Articoli di riviste: "Colored PV"

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Abdulmunem, Abdulmunem R., Abdullateef A. Jadallah, Hisham A. Hoshi e Mohammed H. Jabal. "Effect of Colored Filters on PV Panels Temperature and Performance under Baghdad Meteorological Condition". Tikrit Journal of Engineering Sciences 25, n. 4 (15 dicembre 2018): 45–49. http://dx.doi.org/10.25130/tjes.25.4.08.

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In this work, the influence of colors of filters upon the photovoltaic panels rising temperature and electrical performance was studied under Baghdad Meteorological Condition. Basing on the energy analysis of a photovoltaic solar system and by using the photonic theory, the available energy on the PV plane system has been evaluated. Seven colored filters each with (85W) PV modules were used in this case study, to reveal the impact of colored filters upon the electrical productivity of PV panel with the variation in the temperature caused by these filters. There is the main issue of this work is to show how the performance of PV module by imposing colored filter and hence how and to how much improve it by reducing the cell temperature in hot climate. Outcomes showed that the PV technology is affected by the color filters. In other words, red filter gives light have least photons energy, and violet filter gives light have the most photons energy and green is between the two. So, red colors filter gives highest PV panel temperature comparative with others filters, while violet color filter was the lowest. PV module with the lowest temperature colored filter gives the best electrical performance than others.

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Song, Hyung-Jun, e Hyunho Lee. "Colored Photovoltaics via Printing Technology". Journal of Flexible and Printed Electronics 1, n. 1 (agosto 2022): 29–44. http://dx.doi.org/10.56767/jfpe.2022.1.1.29.

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Building integrated photovoltaic (BIPV) plays an essential role in realizing net-zero energy buildings. Unlike utility-scale photovoltaic (PV) power plants, the aesthetic of BIPV is a crucial issue for entering the market. Therefore, the demand for colored PV increases rapidly to fulfilling the increased energy consumption in an urban area. In this review, we would like to introduce the current status of colored PVs and four dominant printing-based approaches for demonstrating them. First, the Fabry-Perot filter, controlling the device's thickness, intensifies the PVs' color. Secondly, bandgap engineering of the light-absorbing layer enables us to generate a color by transmitting a specific range of incident light. Third, the selective layer, multiple stack of two dielectric layer, provides color to PVs. Lastly, the printing of luminophore on the top of PVs makes them colorful by converting high energy photons to visible ones. The progress of colored PV technology will help PVs enter into BIPV market by providing an aesthetic view to them.

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Hategan, Sergiu-Mihai, e Marius Paulescu. "Spectral Factor of Colored Solar Cells: A Case Study on the Main Urban Areas in Romania". International Journal of Photoenergy 2022 (27 agosto 2022): 1–7. http://dx.doi.org/10.1155/2022/8494818.

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PV modules for Building-Integrated Photovoltaic (BIPV) applications are made of different colors aimed at raising the visual aesthetic of the building. But a colored coating applied to the surface of a basic PV module is inherently associated to a decrease in conversion efficiency. From a different perspective, the efficiency of a PV module is evaluated under the industry standard test conditions (STC). Due to spectral mismatch, the efficiency of a PV module operating in outdoor conditions may substantially differ from the standard value evaluated at STC. In this study, the influence of spectral solar irradiance distribution on the colored PV module efficiency is evaluated in terms of spectral factor (SF). SF quantifies the relative power gain or loss caused by the spectral difference from STC. The theory is illustrated with a case study on the main four urban areas in Romania. The actual solar radiation spectrum is estimated with the simple Leckner spectral solar irradiance model, based on atmospheric parameters retrieved from the Aerosol Robotic Network (AERONET). The results emphasize that the aesthetic of BIPV comes at a high energy cost: depending on the color, a coating applied on the surface of a crystalline silicon PV module may reduce its conversion efficiency even by half.

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Njok, A. O., J. C. Ogbulezie e N. A. Akonjom. "Evaluation of the Performance of Photovoltaic System under different Wavelengths from Artificial Light in a Controlled Environment". Journal of Applied Sciences and Environmental Management 26, n. 6 (30 giugno 2022): 1015–20. http://dx.doi.org/10.4314/jasem.v26i6.4.

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Photovoltaics cell behave in a unique way when light falls on it. The objective of this work is to evaluate the performance of photovoltaic system under different wavelengths from artificial light in a controlled environment. Measurements were first taken from the PV module in the absence of the filters, followed by each filter been placed individually and measurement taken correspondingly. From the results obtained the PV module was most efficient when the yellow colored filter was employed and least efficient with the blue filter (revealing a difference of 2% in efficiency between them). Nevertheless, the photovoltaic module surpassed the efficiencies reached with the application of the colored filters when left open to the natural spectrum.

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Okoth, Michael, Joseph Aloo e Jasper Imungi. "Storage Stability of Refined Oil From Lake Victoria Nile Perch (Lates Niliticus) Viscera". Current Research in Nutrition and Food Science Journal 3, n. 3 (23 dicembre 2015): 237–42. http://dx.doi.org/10.12944/crnfsj.3.3.07.

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Nile perch (Lates niloticus) viscera oil was extracted by wet rendering method and refined by neutralization, deodorization and winterization. After winterization, the oil was decanted and separated by filtration into a low melting point fraction (LMPF) and a high melting point fraction (HMPF). The two fractions were used to carry out storage stability study. Each fraction was stored at room temperature (19 – 23oC) for a period of 20 weeks in transparent and amber colored glass containers. The oil fractions were subjected to quality tests to assess their storage stability. The effects of package color and storage duration were assessed by analyzing for the content of free fatty acids (FFA) as oleic acid and the peroxide value (PV) at the beginning of storage and at intervals of two weeks during storage. The resulting data were subjected to statistical analysis (p ≤ 0.05) using GenStat software, 13th edition. There was a general increase in FFA and PV, with significant differences between oil fractions and package color over storage time. For FFA, there was no interaction between the oil fraction and package color while for PV there was significant interaction between the oil fraction and package color. FFA increased from 0.26% to 0.59% for LMPF in clear package, 0.26 – 0.43% for LMPF in red package, 0.22 – 0.85% for HMPF in clear package, and 0.22 – 0.69% for HMPF in red package. PV increased from 0.50 mEq O2/kg oil to 11.65 mEq O2/kg oil for LMPF in clear package, from 0.5058 mEq O2/kg oil to 10.58 mEq O2/kg oil for LMPF in red package, from 1.01 mEq O2/kg oil to 9.94 mEq O2/kg oil for HMPF in clear package, after 20 weeks, and from 1.01 mEq O2/kg oil – 6.86 mEq O2/kg oil for HMPF in red package after 14 weeks. The levels of FFA and PV of LMPF in colored package remained within the CODEX limits of 0.3% and 5 mEq O2/kg oil respectively for refined fish oils up to 18 weeks. The FFA of HMPF surpassed the limit after 6 and 10 weeks for transparent and colored packages respectively. The FFA of LMPF in transparent package surpassed the limit after 8 weeks. Only low melting point oil fraction in transparent pack had PV above limit at 18 weeks. Results showed that colored package is more suitable for both oil fractions studied. In terms of FFA and PV, HMPF and LMPF can retain good quality at ambient temperatures for 10 and 18 weeks respectively.

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Basher, Mohammad Khairul, Mohammad Nur-E-Alam, Md Momtazur Rahman, Steven Hinckley e Kamal Alameh. "Design, Development, and Characterization of Highly Efficient Colored Photovoltaic Module for Sustainable Buildings Applications". Sustainability 14, n. 7 (4 aprile 2022): 4278. http://dx.doi.org/10.3390/su14074278.

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The building integrated photovoltaic (BIPV) system is one of the contributors which has enormous potential to reach the goal of net-zero energy buildings (NZEB) that significantly reduce the use of fossil fuels that contribute to global warming. However, the limitations of the visual and aesthetic appearance of current BIPV systems make this aspiration unlikely. This study investigates the limitations of the single-color-based PV modules that are dull in appearance and have low photo-conversion efficiency (PCE). In order to solve this issue, we designed, developed, and characterized micro-patterned-based multicolored photovoltaic (MPCPV) modules which are applicable to net-zero building and development. Our newly developed MPCPV module exhibits an aesthetically attractive and flexible building color suitable for industrial application. Furthermore, the MPCPV module possesses an efficiency of 9.6%, which is 4.1% higher than a single-color PV module (5.5%) but closer to conventional thin-film PV modules. In addition, the other output parameters, such as short-circuit current (Isc), open-circuit voltage (Voc), maximum power (Pmax), and fill factor (FF), indicate that our developed colored PV module is suitable for modern infrastructures that will enable energy generation on-site without compromising the aesthetic appearance. Finally, this research will have a substantial influence on the NZEB and will play an important part in the development of a sustainable environment.

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Saw, Min Hsian, Jai Prakash Singh, Yan Wang, Karl Erik Birgersson e Yong Sheng Khoo. "Electrical Performance Study of Colored c-Si Building-Integrated PV Modules". IEEE Journal of Photovoltaics 10, n. 4 (luglio 2020): 1027–34. http://dx.doi.org/10.1109/jphotov.2020.2981820.

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Habets, R., Z. Vroon, B. Erich, N. Meulendijks, D. Mann e P. Buskens. "Structural color coatings for high performance BIPV". IOP Conference Series: Earth and Environmental Science 855, n. 1 (1 ottobre 2021): 012011. http://dx.doi.org/10.1088/1755-1315/855/1/012011.

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Abstract Building integrated photovoltaics (BIPV) offer aesthetics and freedom of design for architects and home owners. This can accelerate implementation and free up new spaces for solar energy harvesting at building level, which is a necessary step towards a climate neutral built environment. Colored solar panels with high conversion efficiency and low cost price are an important development for large scale market penetration of BIPV. Here we report a solution processed structural color coating for solar panels and solar collectors. We show that virtually any color can be prepared, that the desired coating stack can be designed using optical calculations and that the exact color can be produced via a low cost solution process. Furthermore, we show that the light transmission for the colored glass plates is still very high, exceeding commonly used absorbing colors and enables very high solar cell efficiency. The colored PV panels have been tested in real environment and via accelerated lifetime testing for 3 years without any performance decline or degradation.

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Kazem, Hussein A., e Miqdam T. Chaichan. "The Impact of Using Solar Colored Filters to Cover the PV Panel in Its Outcomes". Scholars Bulletin 2, n. 7 (luglio 2016): 464–69. http://dx.doi.org/10.21276/sb.2016.2.7.5.

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Riedel, Benjamin, Paul Messaoudi, Ya Brigitte Assoa, Philippe Thony, Rayan Hammoud, Laure-Emmanuelle Perret-Aebi e John A. Tsanakas. "Color coated glazing for next generation BIPV: performance vs aesthetics". EPJ Photovoltaics 12 (2021): 11. http://dx.doi.org/10.1051/epjpv/2021012.

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Through the H2020 BE-SMART project, we work on the validation and industrialization of new materials (and processes) for manufacturing next-generation cost-efficient, reliable and highly aesthetic/performing BIPV. On this basis, we aim at introducing novel multifunctional and transformative BIPV elements, in the concept/form of Energy Positive Glazing (EPoG). The project's developments so far indicate the high potential of e.g. using colored encapsulants, interferential filter technique and/or ceramic-based colored glazing for implementing novel “transformative” BIPV with high aesthetic quality. Yet, since BIPV's primary function is electricity production, we need to understand and quantify the impact of such coloration solutions on the performance (and reliability, in longer terms) of future BIPV. In this paper, we present an experimental comparative study on the optical and electrical performance of multiple color coated and patterned BIPV glazing solutions, towards their upscaling and commercialization. In particular, we performed optical transmission measurements and light intensity-/angle-depent IV characterization on 25 different colored glass samples and 10 different colored/patterned glass PV laminates respectively. The measurement results and their discussion presented in this paper provide valuable insights into the optical-electrical performance of the investigated colored BIPV glazing, as well as a first identification of BIPV industry-relevant colors and patterns with the best potential “compromise” between aesthetics and performance, for future energy positive glazing applications.

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Roslan, N., M. E. Ya’acob, D. Jamaludin, Y. Hashimoto, M. H. Othman, A. Noor Iskandar, M. R. Ariffin et al. "Dye-Sensitized Solar Cell (DSSC): Effects on Light Quality, Microclimate, and Growth of Orthosiphon stamineus in Tropical Climatic Condition". Agronomy 11, n. 4 (26 marzo 2021): 631. http://dx.doi.org/10.3390/agronomy11040631.

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The main challenge facing greenhouse designers is to achieve environment-appropriate greenhouses, especially in tropical regions. The excess radiant energy transmitted into the greenhouse predisposes plants to photo-inhibition and consequently reduces crop production. Lately, photovoltaic (PV) modules are equipped as a greenhouse rooftop to minimize the level of irradiation and air temperature in the greenhouse, simultaneously improving its energy consumption. Nevertheless, due to the low level of irradiation, denser conventional PV internal shading would influence the cultivated crops’ growth. Thus, Dye Sensitized Solar Cell (DSSC) possesses several attractive features such as transparent, sensitive to low light levels, and various color options that render DSSC a perfect choice able to serve substantially in energy buildings. This study assessed the microclimate conditions inside the greenhouse with semi-transparent DSSC mounted on top of it, describing the Photosynthetic Photon Flux Density (PPFD) (µmol m−2 s−1), Vapor Pressure Deficit VPD (kPa), relative humidity (%), and also temperature (°C). The Overall Thermal Transfer Value (OTTV), which indicates the average thermal energy transmission rate across the external layer of a structure envelope, is also presented. The effects of colored DSSC in altering the spectral of sunlight in reference to the Orthosiphon stamineus growth responses were determined. The information of the condition of DSSC greenhouse microclimate helps to identify the information for designing PV greenhouses and to produce income from both electric power and agronomic activity.

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Gangopadhyay, Utpal, Sukhendu Jana, Sayan Das, Sutapa Garain e Soma Ray. "Antireflective Nanocomposite Based Coating on Crystalline Silicon Solar Cells for Building-Integrated Photovoltaic Systems". Conference Papers in Energy 2013 (29 maggio 2013): 1–6. http://dx.doi.org/10.1155/2013/829260.

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Building-integrated photovoltaic (BIPV) systems represent an interesting, alternative approach for increasing the available area for electricity production and potentially for further reducing the cost of solar electricity. In BIPV systems, the visual impression of a solar module becomes important, including its color. However, the range of solar cell colours and shapes currently on offer to architects and BIPV system designers is still very limited, and this is a barrier to the widespread use of PV modules as a constructional “material.” The color of a solar module is determined by the color of the cells in the module, which is given by the antireflection coating (ARC). However, access to efficient, but differently colored, solar cells is important for the further development of BIPV systems. In this paper, we have used Diamond-like nanocomposite layer as an Antireflective Nanocomposite based (ARNAB) coating material for crystalline silicon solar cell, and the impact of varying the color of an ARC upon the optical characteristics and efficiency of a solar cell is investigated. In addition to a comparison of the optical characteristics of such solar cells, the effect of using colored ARCs on solar cell efficiency is quantified using the solar cell modeling tool PC1D.

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Ivey, M. L. Lewis, S. Wright e S. A. Miller. "Report of Bacterial Leaf Spot on Collards and Turnip Leaves in Ohio". Plant Disease 86, n. 2 (febbraio 2002): 186. http://dx.doi.org/10.1094/pdis.2002.86.2.186a.

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In 2000, circular water-soaked lesions typical of bacterial leaf spot were observed on leaves of collards (Brassica oleracea L. var. viridis) throughout commercial fields in northwest Ohio. Light brown, rectangular, water-soaked lesions were observed on turnip leaves (Brassica rapa L.). Bacterial streaming from lesions on both crops was observed microscopically. Cream colored, fluorescent colonies were isolated from diseased tissues on Pseudomonas F medium, and eight representative colonies (four from collards and four from turnip) were selected and purified. Fatty acid methyl ester analysis was performed on all of the isolates. Two from collards and two from turnip were identified as Pseudomonas syringae pv. maculicola (mean similarity index = 0.82 [MIDI Inc., Newark, DE]). DNA extracts from pure cultures of the P. syringae pv. maculicola strains were used as template in a polymerase chain reaction (PCR) assay with primers derived from the region of the coronatine gene cluster controlling synthesis of the coronafacic acid moiety found in P. syringae pv. tomato and P. syringae pv. maculicola (CorR and CorF2) (D. Cuppels, personal communication). DNA from P. syringae pv. tomato strain DC3000 and P. syringae pv. maculicola strain 88–10 (2) served as positive controls, while water and DNA from Xanthomonas campestris pv. vesicatoria strain Xcv 767 were used as negative controls. The expected 0.65-kb PCR product was amplified from three of four strains (two from turnip and one from collards) and the positive control DNA, but not from the negative controls. Pathogenicity tests were performed twice on 6-week-old turnip (‘Forage Star’, ‘Turnip Topper’, ‘Turnip Alamo’, ‘Turnip 7’), collard (‘Champion’) and mustard (Brassica juncea L. ‘Southern Giant Curl’) seedlings using the three PCR-positive strains. Premisted seedlings were spray-inoculated separately with each of the three strains (2 × 108 CFU/ml, 5 ml per plant) and a water control. Greenhouse temperatures were maintained at 20 ± 1°C. For both tests, all strains caused characteristic lesions on all of the crucifer cultivars within 5 days after inoculation; the control plants did not develop symptoms. To satisfy Koch's postulates, one of the turnip strains was reisolated from ‘Turnip Topper’ plants, and the collard strain was reisolated from ‘Champion’ plants. The three original and two reisolated strains induced a hypersensitive response in Mirabilis jalapa L. and Nicotiana tabacum L. var. xanthia plants 24 h after inoculation with a bacterial suspension (1 × 108 CFU/ml). The original and reisolated strains were compared using rep-PCR with the primer BOXA1R (1). The DNA fingerprints of the reisolated strains were identical to those of the original strains. To our knowledge, this is the first report of bacterial leaf spot on commercially grown collards and turnip greens in Ohio. References: (1) B. Martin et al. Nucleic Acids Res. 20:3479, 1992. (2) R. A. Moore et al. Can. J. Microbiol. 35:910, 1989.

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Gumtow, R. L., A. A. Khan, A. M. Bocsanczy, J. M. F. Yuen, A. J. Palmateer e D. J. Norman. "First Report of a Leaf Spot Disease of Golden Dewdrop (Duranta erecta) Caused by Pseudomonas cichorii and a Xanthomonas Species in Florida". Plant Disease 97, n. 6 (giugno 2013): 836. http://dx.doi.org/10.1094/pdis-12-12-1117-pdn.

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Duranta erecta (Verbenaceae) is used extensively in southern states as an ornamental shrub and has replaced boxwood as the most common short hedge accenting flower beds. Over the past 2 years, during warm wet periods, dark necrotic leaf spots have been observed on golden dewdrop plants in Florida. Isolations from these spots on Difco nutrient agar (NA) consistently yielded two types of bacterial colonies that were not always simultaneously present: 1) round butyrous, bright yellow and 2) flat cream-colored. Both were 2 mm in size after 48 h, gram-negative, and produced a hypersensitivity reaction (HR) on tobacco cv Hicks. Yellow colony bacteria were oxidase negative and non-fluorescent on King's medium B (KMB) (1). Cream-colored colony bacteria were oxidase positive and fluorescent on KMB. Three isolates of both types were selected for further study. Partial 16S rDNA sequencing and fatty acid analysis (FAME) MIDI Microbial Identification System (Microbial ID, Inc., Newark, DE) were used for identification of strains. The 16S rDNA primers used were; forward primer AMB14 5′-TCCAGCAATGCCGCGTGTGT-3′ and reverse primer AMB13 5′-CATCCACCGCTTGTGCGGGT-3′. The PCR program consisted of an initial denaturing cycle of 95°C for 2 min followed by 30 cycles of denaturing at 95°C for 30 s, annealing at 60°C for 40 s and extension at 72°C for 1 min and one final extension at 72°C for 10 min. Using FAME analysis, the three strains of the cream-colored colony type were identified as Pseudomonas cichorii with high similarity values (0.907, 0.961, 0.819) and this corresponded well with the 16S rDNA sequences where 99% sequence identity was observed with P. cichorii strain JBC1 16S ribosomal RNA gene, partial sequence GenBank Accession No. JF951725. Two of the three yellow colony strains were identified by MIDI FAME profiles as Xanthomonas axonopodis pv. manihotis with similarity coefficients of 0.767 and 0.826. The third strain had a low similarity match to X. a. pv. carotae (0.541). The 16S rDNA sequencing of these strains showed 98% sequence identity to X. citri subsp. citri strain SA1 16S ribosomal RNA gene only, partial sequence identity JQ890091.1, thus indicating a possible undescribed X. axonopodis pathovar. To satisfy Koch's postulates, three golden dewdrop ‘Golden Mound’ plants were sprayed with a suspension of 108 CFU/ml of a 2-day NA culture of each strain, bagged for 24 h to raise humidity, and placed in a greenhouse. A strain of P. cichorii (P409) isolated from chrysanthemum was used as a positive control when comparing cream-colored strains. A saline buffered control was used as a negative control. Within 3 weeks, leaf spots developed on plants sprayed with each of the six strains, including positive control strain of P. cichorii. Reisolations yielded the same type of colony as the originally inoculated strain. Inoculation experiments were repeated three times with a minimum of three plants per isolate with similar results. To our knowledge, this is the first report in the United States of bacterial leaf spot caused by P. cichorii and X. axonopodis on golden dewdrop. An earlier morphological and physiological description of a Xanthomonas sp. was done on Duranta in India in 1962 (2). Due to the difficulty in controlling bacterial diseases and the popularity of Duranta spp. in the landscape, these diseases may present a problem in ornamental trade. References: (1) E. O. King et al. J. Lab. Clin. Med. 44:301, 1954. (2) M. C. Srinivasan et al. Proc. Indian Acad. Sci. 56:88, 1962.

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Katsigiannis, Yiannis A., Pavlos S. Georgilakis e George J. Tsinarakis. "A Novel Colored Fluid Stochastic Petri Net Simulation Model for Reliability Evaluation of Wind/PV/Diesel Small Isolated Power Systems". IEEE Transactions on Systems, Man, and Cybernetics - Part A: Systems and Humans 40, n. 6 (novembre 2010): 1296–309. http://dx.doi.org/10.1109/tsmca.2010.2052607.

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Lu, Shi-En, e Dennis C. Gross. "Drippy Pod of White Lupine: A New Bacterial Disease Caused by a Pathovar of Brenneria quercina". Plant Disease 94, n. 12 (dicembre 2010): 1431–40. http://dx.doi.org/10.1094/pdis-05-10-0365.

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Drippy pod is a unique bacterial disease of Mediterranean white lupine (Lupinus albus) that first appeared in commercial fields in Eastern Washington State in the mid-1980s. The disease is most noticeable in the field as water-soaked lesions on lupine pods that produce an abundance of whitish-colored ooze with a sticky and foamy consistency. As the disease progresses, yellowing of lupine plants occurs with ooze characteristically dripping down the infected pods and stems and solidifying. A gram-negative rod-shaped bacterium with facultative anaerobic growth was repeatedly isolated from infected lupine tissues, and subsequently confirmed by Koch's postulates to infect lupines. Physiological and biochemical tests, including the API 20E and 50CHE strip assays, showed a highly uniform phenotype for the lupine strains that was distinctive for the genus Brenneria and most closely resembled the oak pathogen Brenneria quercina. Furthermore, sequence analyses of the 16S rDNA gene and the 16S-23S intergenic region of lupine strains revealed the highest similarity (>97%) to the corresponding regions of B. quercina and less similarity to the next closest species, B. salicis. Fatty acid profiling demonstrated that lupine strains were qualitatively similar in composition to Brenneria spp., and supported placement of the drippy pod bacterium in the species B. quercina. Oak strains of B. quercina, however, did not incite drippy pod disease on lupine. Consequently, the lupine strains that cause bacterial drippy pod disease were classified as B. quercina pv. lupinicola pv. nov.

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Wagih, Elsayed E., e Jacqueline Fletcher. "Zymoblot, a new microtechnique used to detect enzyme activity in spiroplasmas and bacteria". Canadian Journal of Microbiology 39, n. 5 (1 maggio 1993): 543–47. http://dx.doi.org/10.1139/m93-077.

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A new microtechnique that detects enzyme activity in prokaryotes is described. The technique, designated zymoblot, is based on the immobilization of negatively charged enzymes from an alkaline extract spotted onto a nitrocellulose membrane. The presence of specific enzyme activity in the extract is selectively assayed with a reaction mixture containing the corresponding substrate. The enzyme–substrate reaction produces an insoluble colored product that accumulates at the site. The zymoblot technique offers the advantages of simplicity, sensitivity, reproducibility, speed, and the use of microquantities of reactants. The protein in the spot can be visualized by a technique termed "proteinblot," in which the protein is stained with Coomassie blue. Esterase and tyrosinase were detected by the zymoblot method in six spiroplasmas including four strains of Spiroplasma citri, one of Spiroplasma kunkelii, and one of Spiroplasma melliferum, and two bacteria, Pseudomonas syringae pv. syringae B301D and Escherichia coli K-12. Acid phosphatase, alkaline phosphatase, alanine dehydrogenase, peroxidase, and 6-phosphogluconate dehydrogenase were not detected in any of the spiroplasmas, but were each detected in one or both of the walled bacteria.Key words: spiroplasma, enzyme, protein, zymoblot.

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Hayes, Ryan J., Mark A. Trent, Beiquan Mou, Ivan Simko, Samantha J. Gebben e Carolee T. Bull. "Baby Leaf Lettuce Germplasm Enhancement: Developing Diverse Populations with Resistance to Bacterial Leaf Spot Caused by Xanthomonas campestris pv. vitians". HortScience 49, n. 1 (gennaio 2014): 18–24. http://dx.doi.org/10.21273/hortsci.49.1.18.

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Baby leaf lettuce cultivars with resistance to bacterial leaf spot (BLS) caused by Xanthomonas campestris pv. vitians (Xcv) are needed to reduce crop losses. The objectives of this research were to assess the genetic diversity for BLS resistance in baby leaf lettuce cultivars and to select early generation populations of lettuce with BLS resistance. Greenhouse experiments using artificial Xcv inoculations were conducted to assess BLS resistance in 35 cultivars of 10 lettuce types used in baby leaf production and in F2 through F3:4 progeny from ‘Batavia Reine des Glaces’ (BLS-resistant, green leaf color) × ‘Eruption’ (BLS-susceptible, red leaf color). Higher disease severity was identified in red leaf and red romaine cultivars compared with other types, indicating the need to target these types for resistance breeding. Selection for BLS resistance and red-colored leaves was therefore conducted among 486 F2 plants, 38 F2:3 families, and two populations of F3:4 families from ‘Batavia Reine des Glaces’ × ‘Eruption’. Two populations were identified with uniform levels of BLS resistance equivalent to ‘Batavia Reine des Glaces’ and variable leaf morphology and color. These populations can be used by private and publicly employed lettuce breeders to select for diverse types of lettuce cultivars suitable for baby leaf production and with BLS resistance.

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Tasliah, Tasliah, Mahrup Mahrup e Joko Prasetiyono. "Identifikasi Molekuler Hawar Daun Bakteri (Xanthomonas oryzae pv. oryzae) dan Uji Patogenisitasnya pada Galur-galur Padi Isogenik". Jurnal AgroBiogen 9, n. 2 (23 agosto 2016): 49. http://dx.doi.org/10.21082/jbio.v9n2.2013.p49-57.

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Identification of Xanthomonas oryzae pv. oryzae (Xoo) based on molecular analysis has been introduced just few years ago. This method used some specific primers for Xoo and can be done quickly. The purposes of this research were to identify isolate Xoo originated from five locations in Indonesia and to determine the level of pathogenicity of these bacteria. Studies were conducted in the greenhouse and the Molecular Biology Laboratory of ICABIOGRAD, from 2011 to 2012. Bacterial isolates were taken from five regions in Indonesia, namely: West Sumatra, West Java, Central Java, South Sulawesi, and West Kalimantan. The specific primers of Xoo were Xoo2967, Xoo80, and Xoo. Results showed that 216 isolates could be grown to form yellow colored colonies, which belongs to a criterian for Xoo. Molecular analysis demonstrated that 189 isolates were Xoo and 27 isolates were not. Amplification of DNA of the isolates resulted a 337 bp PCR product for primer Xoo2976, 700 bp for primer Xoo80 and 534 bp for primer Xoo. Pathogenicity tests of the Xoo isolates showed xa5, Xa7, and Xa21 resistance genes were still effective againts BLB pathogens originated from those five regions, with percentage of resistance were 93.57, 77.49, and 85.37%, respectively.

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Koike, S. T., H. R. Azad e D. C. Cooksey. "First Report of Bacterial Leaf Spot of Spinach Caused by a Pseudomonas syringae Pathovar in California". Plant Disease 86, n. 8 (agosto 2002): 921. http://dx.doi.org/10.1094/pdis.2002.86.8.921a.

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Abstract (sommario):

In 2000 and 2001, a new disease was observed on commercial spinach (Spinacia oleracea) in the Salinas Valley, Monterey County, CA. Initial symptoms were water-soaked, irregularly shaped leaf spots (2 to 3 mm diameter). As the disease developed, spots enlarged to as much as 1 to 2 cm, were vein-delimited, and turned dark brown. Faint chlorotic halos sometimes surrounded the spots. Death of large areas of the leaf occurred if spots coalesced. Spots were visible from the adaxial and abaxial sides of leaves, and no fungal structures were observed. The disease occurred on newly expanded and mature foliage. No fungi were isolated from the spots. However, cream-colored bacterial colonies were consistently isolated on sucrose peptone agar, and these strains were nonfluorescent on King's medium B. Strains were positive for levan and negative for oxidase, arginine dihydrolase, and nitrate reductase. Strains did not grow at 36°C, did not rot potato slices, but induced a hypersensitive reaction in tobacco (Nicotiana tabacum cv. Turk). These results suggested the bacterium was similar to Pseudomonas syringae. Fatty acid methyl ester (FAME) analysis (MIS-TSBA 4.10, MIDI Inc., Newark, DE) indicated the strains were highly similar (80.1 to 89.3%) to P. syringae pv. maculicola. However, in contrast to P. syringae pv. maculicola, the spinach strains did not utilize the carbon sources erythritol, L+tartrate, L lactate, and DL-homoserine. Pathogenicity of 10 strains was tested by growing inoculum in nutrient broth shake cultures for 48 h, diluting to 106 CFU/ml, and spraying 4-week-old plants of spinach cv. Bossanova. Control plants were sprayed with sterile nutrient broth. After 5 to 8 days in a greenhouse (24 to 26°C), leaf spots identical to those observed in the field developed on cotyledons and true leaves of inoculated plants. Strains were reisolated from the spots and identified as P. syringae. Control plants remained symptomless. The 10 strains were also inoculated on beet (Beta vulgaris), Swiss chard (Beta vulgaris subsp. cicla), cilantro (Coriandrum sativum), and spinach. Spinach showed leaf spots after 8 days; however, none of the other plants developed symptoms. Two strains were inoculated onto spinach cvs. Califlay, Lion, Nordic IV, Polka, Resistoflay, Rushmore, RZ 11, Spinnaker, Springfield, Viroflay, and Whitney. Leaf spot developed on all cultivars, and the pathogen was reisolated. Because the FAME data indicated a similarity between the spinach pathogen and P. syringae pv. maculicola, we inoculated sets of spinach cv. Bolero, cabbage (Brassica oleracea subsp. capitata cv. Grenedere), and cauliflower (Brassica oleracea subsp. botrytis cv. White Rock) with three P. syringae pv. maculicola and three spinach strains. Cabbage and cauliflower developed leaf spots only when inoculated with P. syringae pv. maculicola; spinach had leaf spots only when inoculated with the spinach strains. All inoculation experiments were done twice, and the results of the two tests were the same. To our knowledge, this is the first report of bacterial leaf spot of spinach in California caused by a nonfluorescent P. syringae, and the first record of this disease in the United States. Biochemical characteristics and limited host range of the pathogen indicate the California strains are likely the same as the P. syringae pv. spinaciae pathogen that was reported in Italy (1) and Japan (2). References: (1) C. Bazzi et al. Phytopathol. Mediterr. 27:103, 1988. (2) K. Ozaki et al. Ann. Phytopathol. Soc. Jpn. 64:264, 1998.

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21

Amin, Tabasia, Vishal Gupta, Akash Sharma, Pardeep Kumar Rai, Vijay Kumar Razdan, Satish Kumar Sharma, Santosh Kumar Singh et al. "Distribution of Xanthomonas oryzae pv. oryzae Pathotypes in Basmati-Rice-Growing Areas of Jammu and Kashmir, India". Agronomy 13, n. 3 (27 febbraio 2023): 713. http://dx.doi.org/10.3390/agronomy13030713.

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Rice is an important staple food for more than half of the world’s population. Though the genetic potential of commonly cultivated varieties of rice is diminished due to various biotic and abiotic constraints, bacterial leaf blight (BLB) of rice caused by Xanthomonas oryzae pv. oryzae (Xoo) is considered one of its most destructive diseases in India. Based on morpho-cultural characteristics, bacterial pathogens isolated from the leaves of a rice plant showing typical BLB symptoms were identified as Xanthomonas oryzae pv. oryzae. Morphological studies revealed that the pathogen is Gram-negative, a short rod, with rounded ends, single or in pairs, light yellow, circular, whitish yellow to straw-colored, convex, yellow, slightly raised, motile with a single polar flagellum, capsulate and non-spore-forming. Biochemical tests, viz., the Gram reaction, KOH test and catalyst test, showed a positive reaction for all the isolates. Twenty isolates of Xoo were collected from the basmati-growing areas of the Jammu, Samba and Kathua districts in the Jammu sub-tropics during 2019, and their pathogenicity was confirmed on five susceptible rice cultivars, viz., Basmati-370, Pusa-1121, TN-1, SJR and Jaya, by the leaf-clipping method, and subsequently, Koch’s postulate was established in each case. Seven Xoo pathotypes, viz., Pathotype 1, Pathotype 2, Pathotype 3, Pathotype 4, Pathotype 5, Pathotype 6 and Pathotype 7, were identified from the total sample of 20 isolates. Pathotype 2 was the most dominant (100%), followed by Pathotype 5 (44.44%), Pathotype 4 (40%), Pathotype 6 (40%), Pathotype 7 (33.33%), Pathotype 3 (22.22%) and Pathotype 1 (20%), in the Jammu sub-tropics. In Jammu district, Pathotype 5 was highly distributed (44.44%) followed by Pathotype 7 (33.33%) and Pathotype 3 (22.22%). Pathotype 4 and Pathotype 6 each showed a 40 percent distribution in Kathua district, followed by Pathotype 1 (20%). Only one pathotype, i.e., Pathotype 2, was recorded in Samba district with a 100 percent distribution. Five genes, viz., Xa13, Xa4, Xa13 and Xa5 + Xa13, showed complete resistance, whereas Xa4, Xa5, Xa7, Xa8, Xa21, Xa4 + Xa5 and Xa4 + Xa21 showed susceptible response against the test isolates. It was observed that most of the single BLB-resistant genes were moderately to highly susceptible to almost all the Xoo isolates, whereas combinations of BLB resistance genes possessed high resistance against all the Xoo isolates. The studies revealed that diverse pathogenic variations existed in the Xoo population in the basmati-growing region of Jammu and Kashmir. Based on the response exhibited by Xoo isolates on differential lines, seven pathotypes (Pathotype 1–7) were identified, and their virulence spectrum on rice differentials showed the occurrence of 5, 3, 10, 10, 20, 10 and 15 percent, respectively, in the Jammu sub-tropics. To develop durable and sustainable resistant cultivars, it is essential to identify predominate race(s) in a specific geographical area and continuously monitor the virulence pattern there.

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22

Koike, S. T., D. M. Henderson, C. T. Bull, P. H. Goldman e R. T. Lewellen. "First Report of Bacterial Leaf Spot of Swiss Chard Caused by Pseudomonas syringae pv. aptata in California". Plant Disease 87, n. 11 (novembre 2003): 1397. http://dx.doi.org/10.1094/pdis.2003.87.11.1397b.

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Abstract (sommario):

From 1999 through 2003, a previously unreported disease was found on commercial Swiss chard (Beta vulgaris subsp. cicla) in the Salinas Valley, (Monterey County) California. Each year the disease occurred sporadically throughout the long growing season from April through September. Initial symptoms were water-soaked leaf spots that measured 2 to 3 mm in diameter. As disease developed, spots became circular to ellipsoid, 3 to 8 mm in diameter, and tan with distinct brown-to-black borders. Spots were visible from the adaxial and abaxial sides. Cream-colored bacterial colonies were consistently isolated from spots. Strains were fluorescent on King's medium B, levan positive, oxidase negative, and arginine dihydrolase negative. Strains did not rot potato slices but induced a hypersensitive reaction on tobacco (Nicotiana tabacum cv. Turk). The isolates, therefore, belong in LOPAT group 1 (1). Fatty acid methyl esters (FAME) analysis (MIS-TSBA version 4.10, MIDI Inc., Newark, DE) gave variable results that included Pseudomonas syringae, P. cichorii, and P. viridiflava with similarity indices ranging from 0.91 to 0.95. BOX-polymerase chain reaction (PCR) analysis gave identical banding patterns for the chard isolates and for known P. syringae pv. aptata strains, including the pathotype strain CFBP1617 (2). The bacteria were identified as P. syringae. Pathogenicity of 11 strains was tested by growing inoculum in nutrient broth shake cultures for 48 h, diluting to 10 × 6 CFU/ml, and spraying onto 5-week-old plants of Swiss chard cvs. Red, White, Silverado, and CXS2547. Untreated control plants were sprayed with sterile nutrient broth. After 7 to 10 days in a greenhouse (24 to 26°C), leaf spots similar to those observed in the field developed on all inoculated plants. Strains were reisolated from the spots and identified as P. syringae. Control plants remained symptomless. To investigate the host range of this pathogen, the same procedures were used to inoculate three strains onto other Chenopodiaceae plants: five cultivars of sugar beet (B. vulgaris), and one cultivar each of spinach (Spinacia oleracea) and Swiss chard. In addition, five chard strains and strain CFBP1617 were inoculated onto two cultivars of sunflower (Helianthus annuus), and one cultivar each of cantaloupe (Cucumis melo), sugar beet, spinach, and Swiss chard. All Swiss chard, cantaloupe, sunflower, and sugar beet plants developed leaf spots after 7 days. The pathogen was reisolated from spots and confirmed to be the same bacterium using BOX-PCR analysis. Spinach and untreated controls failed to show symptoms. All inoculation experiments were done at least twice and the results were the same. The phenotypic data, fatty acid and genetic analyses, and pathogenicity tests indicated that these strains are P. syringae pv. aptata. To our knowledge this is the first report of bacterial leaf spot of commercially grown Swiss chard in California caused by P. syringae pv. aptata. The disease was particularly damaging when it developed in Swiss chard fields planted for “baby leaf” fresh market products. Such crops are placed on 2-m wide beds, planted with high seed densities, and are sprinkler irrigated. This disease has been reported from Asia, Australia, Europe, and other U.S. states. References: (1) R. A. Lelliott et al. J. Appl. Bacteriol. 29:470, 1966. (2) J. L. W. Rademaker et al. Mol. Microbiol. Ecol. Man. 3.4.3:1–27, 1998.

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23

Huong, Duyen Do Tran, Nagendran Rajalingam e Yong Hoon Lee. "Characterization of Virulence Function of Pseudomonas cichorii Avirulence Protein E1 (AvrE1) during Host Plant Infection". Plant Pathology Journal 37, n. 5 (1 ottobre 2021): 494–501. http://dx.doi.org/10.5423/ppj.nt.07.2021.0108.

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Abstract (sommario):

Pseudomonas cichorii secretes effectors that suppress defense mechanisms in host plants. However, the function of these effectors, including avirulence protein E1 (AvrE1), in the pathogenicity of P. cichorii, remains unexplored. In this study, to investigate the function of avrE1 in P. cichorii JBC1 (PcJBC1), we created an avrE1-deficient mutant (JBC1ΔavrE1) using CRISPR/Cas9. The disease severity caused by JBC1ΔavrE1 in tomato plants significantly decreased by reducing water soaking during early infection stage, as evidenced by the electrolyte leakage in infected leaves. The disease symptoms caused by JBC1ΔavrE1 in the cabbage midrib were light-brown spots compared to the dark-colored ones caused by PcJBC1, which indicates the role of AvrE1 in cell lysis. The avrE1-deficient mutant failed to elicit cell death in non-host tobacco plants. Disease severity and cell death caused by JBC1ΔavrE1 in host and non-host plants were restored through heterologous complementation with avrE1 from Pseudomonas syringae pv. tomato DC3000 (PstDC3000). Overall, our results indicate that avrE1 contributes to cell death during early infection, which consequently increases disease development in host plants. The roles of PcJBC1 AvrE1 in host cells remain to be elucidated.

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24

Chowdappa, Srinivas, Shubha Jagannath, Narasimhamurthy Konappa, Arakere C. Udayashankar e Sudisha Jogaiah. "Detection and Characterization of Antibacterial Siderophores Secreted by Endophytic Fungi from Cymbidium aloifolium". Biomolecules 10, n. 10 (6 ottobre 2020): 1412. http://dx.doi.org/10.3390/biom10101412.

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Endophytic fungi from orchid plants are reported to secrete secondary metabolites which include bioactive antimicrobial siderophores. In this study endophytic fungi capable of secreting siderophores were isolated from Cymbidium aloifolium, a medicinal orchid plant. The isolated extracellular siderophores from orchidaceous fungi act as chelating agents forming soluble complexes with Fe3+. The 60% endophytic fungi of Cymbidium aloifolium produced hydroxamate siderophore on CAS agar. The highest siderophore percentage was 57% in Penicillium chrysogenum (CAL1), 49% in Aspergillus sydowii (CAR12), 46% in Aspergillus terreus (CAR14) by CAS liquid assay. The optimum culture parameters for siderophore production were 30 °C, pH 6.5, maltose and ammonium nitrate and the highest resulting siderophore content was 73% in P. chrysogenum. The total protein content of solvent-purified siderophore increased four-fold compared with crude filtrate. The percent Fe3+ scavenged was detected by atomic absorption spectra analysis and the highest scavenging value was 83% by P. chrysogenum. Thin layer chromatography of purified P. chrysogenum siderophore showed a wine-colored spot with Rf value of 0.54. HPLC peaks with Rts of 10.5 and 12.5 min were obtained for iron-free and iron-bound P. chrysogenum siderophore, respectively. The iron-free P. chrysogenum siderophore revealed an exact mass-to-charge ratio (m/z) of 400.46 and iron-bound P. chrysogenum siderophore revealed a m/z of 453.35. The solvent-extracted siderophores inhibited the virulent plant pathogens Ralstonia solanacearum, that causes bacterial wilt in groundnut and Xanthomonas oryzae pv. oryzae which causes bacterial blight disease in rice. Thus, bioactive siderophore-producing endophytic P. chrysogenum can be exploited in the form of formulations for development of resistance against other phytopathogens in crop plants.

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25

Dutta, B., T. Ingram, R. D. Gitaitis, D. B. Langston, T. Brenneman, T. M. Webster e R. F. Davis. "First Report of Bacterial Blight of Sugar Beet Caused by Pseudomonas syringae pv. aptata in Georgia, USA". Plant Disease 98, n. 10 (ottobre 2014): 1423. http://dx.doi.org/10.1094/pdis-03-14-0235-pdn.

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Sugar beet (Beta vulgaris L.) is not currently a commercial crop in Georgia, but experimental plantings as a winter rotational crop are promising in terms of yield and industrial sugar production (T. Brenneman, personal communication). A disease outbreak of suspected bacterial origin occurred in sugar beet plots (experimental lines Beta Seed energy beet ‘BTS ENC115,’ ‘BTS EGC184,’ ‘BTS EGC195,’ and ‘BTS 1EN6702’) in Tift Co., GA, in December 2012, at ~35% incidence. Foliar symptoms included circular to irregular spots, each with a tan center and dark margin. Ten leaves/experimental line with leaf spot symptoms were collected, and bacterial isolations made on King's B agar medium. After 48 h of incubation, cream-colored, fluorescent yellow, round colonies with smooth margins were isolated. The isolates were each gram negative, oxidase negative, non-pectolytic on potato, arginine dihydrolase negative, produced levan, and gave a hypersensitivity response (HR) on tobacco. These characteristics indicated that the isolates belonged to Pseudomonas syringae van Hall LOPAT group Ia (3). The 16S-23S rRNA (internal transcribed regions) (1) from four foliar isolates (SB-1, SB-2, SB-3, and SB-4), one/experimental line, was amplified, and the resultant PCR products were sequenced and BLAST searched in GenBank. The 16S-23S rRNA sequences matched those of P. syringae pv. syingae (Pss) (KF023189) and P. syringae pv. aptata (Psa) (AY342167.1) with 96 to 98% and 97 to 99% sequence identity, respectively. Also, the percent similarity of the 16S-23S rRNA sequences among the four isolates was >99% (KJ922021 to 24 for SB-1 to SB-4, respectively). The four test isolates also had ≤89 and ≤99% similarity with Pss and Psa, respectively, when tested with BIOLOG (Hayward, CA). In addition, four sugarbeet isolates along with a type strain of Psa (NCPPB 3539) were amplified using a PCR primer pair that detected the presence of the avrPphE gene, an avirulence gene present in Psa but absent in Pss (2). The type strain of Pss (NCPPB 1770) was not amplified using this primer pair. BOX-PCR analysis gave identical banding patterns for the four isolates as that of a type strain of Psa. In two independent experiments, 3-week-old seedlings of the sugar beet cv. Beta EGR099 (n = 10 seedlings/isolate/experiment) were spray-inoculated with a sterilized water suspension of 1 × 108 CFU/ml of each of the isolates. All of the inoculated seedlings developed symptoms (water-soaked lesions that developed into necrotic spots) 10 days after inoculation (DAI) in greenhouse conditions (~30°C and ~80% RH). All of the seedlings inoculated with the type strain of Psa also produced typical bacterial blight symptoms at 10 DAI. In contrast, five control seedlings inoculated with sterilized water remained asymptomatic, and target bacterial colonies were not re-isolated from the leaves of these plants. Bacterial colonies were re-isolated from symptomatic seedlings, and showed similar characteristics based on physiological tests, BIOLOG profile, BOX-PCR analysis, and positive amplification with the avrPphE PCR assay, which indicated that these strains were Psa. To our knowledge, this is the first report of Psa in sugarbeet in Georgia. The fact that a Psa strain was also isolated from a sugar beet seed lot (data not shown) suggested that the pathogen may have been introduced on contaminated seeds. Knowledge of the presence of Psa in the agro-ecosystem of Georgia may encourage scientists to implement integrated management practices for this pathogen. References: (1) C. Guasp et al. Int. J. Syst. Evol. Microbiol. 50:1629, 2000. (2) Y. Inoue and Y. Takikawa. Page 687 in: Presentations 6th Int. Conf. Pseudomonas syringae Pathovars and Related Pathogens, 2003. (3) R. A. Lelliot et al. J. Appl. Bacteriol. 29:470, 1966.

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26

Koike, S. T., e C. T. Bull. "First Report of Bacterial Leaf Spot of Italian Dandelion (Cichorium intybus) Caused by a Pseudomonas syringae Pathovar in California". Plant Disease 90, n. 2 (febbraio 2006): 245. http://dx.doi.org/10.1094/pd-90-0245a.

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Abstract (sommario):

Italian dandelion (Cichorium intybus) is a leafy, nonhead forming chicory plant that is eaten as a fresh vegetable in salads. During the late summer (August through October) of 2002, in the Salinas Valley (Monterey County) in California, a previously unreported disease was found in commercial Italian dandelion fields. Early symptoms were angular, vein delimited, dark, water-soaked leaf spots that measured 2 to 7 mm in diameter. As disease developed, spots retained angular edges but exhibited various irregular shapes. Spots commonly formed along the edges of the leaves; in some cases these spots developed into lesions that measured between 10 and 30 mm long. Spots were visible from adaxial and abaxial sides and were dull black in color. A cream-colored pseudomonad was consistently isolated from leaf spots that were macerated and streaked onto sucrose peptone agar. Fungi were not recovered from any of the spots. Recovered strains were blue-green fluorescent when streaked onto King's medium B agar. Bacterial strains were levan positive, oxidase negative, and arginine dihydrolase negative. Strains did not rot potato slices but induced a hypersensitive reaction on tobacco (Nicotiana tabacum cv. Turk). These data indicated that the bacteria belonged to LOPAT group 1 of Pseudomonas syringae (1). Pathogenicity of six strains was tested by growing inoculum in nutrient broth shake cultures for 48 h, diluting to 106 CFU/ml, and spraying onto 12 6-week-old plants of Italian dandelion cv. Catalogna Special. Untreated control plants were sprayed with sterile nutrient broth. After 10 to 12 days in a greenhouse (24 to 26°C), leaf spots similar to those observed in the field developed on all inoculated plants. Strains were reisolated from the spots and identified as P. syringae. Control plants remained symptomless. These inoculation experiments were done twice and the results were the same. Amplification of repetitive bacterial sequences (repetitive sequence-based polymerase chain reaction [rep-PCR]) demonstrated that all Italian dandelion strains had the same rep-PCR fingerprint, which differed from fingerprints of P. syringae pv. tagetis and P. syringae pv. tabaci. Additionally, toxin specific primers did not amplify tagetitoxin or tabtoxin biosynthesis genes from Italian dandelion strains. To our knowledge, this is the first report of bacterial leaf spot of commercially grown Italian dandelion in California caused by a P. syringae pathovar. Because fields were irrigated with overhead sprinklers, the disease was severe in several fields and as much as 30% of those plantings were not harvested. Reference: (1) R. A. Lelliott et al. J. Appl. Bacteriol. 29:470, 1966.

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27

Corrao, Rossella. "Mechanical Tests on Innovative BIPV Façade Components for Energy, Seismic, and Aesthetic Renovation of High-Rise Buildings". Sustainability 10, n. 12 (30 novembre 2018): 4523. http://dx.doi.org/10.3390/su10124523.

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Abstract (sommario):

The paper shows the results of mechanical tests carried out on prototypes of a new Building Integrated Photovoltaic (BIPV) component developed by the author and SBskin Smart Building Skin s.r.l. This patented innovative component is able to merge structural function, insulation proprieties, and production of clean energy for retrofit actions and/or the construction of translucent façades in high-rise buildings located in different climatic contexts. Due to colored PV cells integrated into 3 Dimensional (3D) glass components and the dry-assembly system used for assembling them into precast and pre-stressed panels, an easy and creative customization of the product is allowed. Green energy production, safety, and energy efficiency of buildings can be assured in accordance with the environmental conditions and users’ needs. The pre-stressing force used to improve the mechanical resistance of the panel toward horizontal forces due to winds and earthquakes guarantees the construction of secure translucent and active building envelopes. The paper summarizes the features of this innovative and patented BIPV product by focusing on its mechanical behavior. Laboratory tests are described and commented for underlining the benefits derived from the use of the dry-assembly system and of the supporting structure made of plastic for the construction of the panels. Bending and breaking strength tests have been carried out on two sq.m of panel prototypes, which have been dry-assembled through a supporting structure made of Polypropylene (PP) in order to compare the results with the theoretical calculations derived from the Finite Element (FE) simulations. Cyclic mechanical testing of the panel has been also carried out to verify its behavior under cyclic loading and understanding its ability to counteract the actions of the wind and earthquake.

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28

Koike, S. T., M. P. Bolda e C. T. Bull. "Pseudomonas Blight Caused by Pseudomonas syringae on Raspberry in California". Plant Disease 98, n. 8 (agosto 2014): 1151. http://dx.doi.org/10.1094/pdis-01-14-0041-pdn.

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Abstract (sommario):

In February 2013 in coastal California (Santa Cruz County), plantings of red raspberry (Rubus idaeus var. strigosus) exhibited symptoms of a previously undocumented disease. Initial symptoms were small (less than 5 mm wide), angular, water-soaked lesions on leaf and petiole tissues of recently emerged foliage. Lesions were observable from both adaxial and abaxial leaf surfaces. As disease progressed, lesions enlarged and coalesced, resulting in significant dark brown to black blighting of the foliage. The foliage of severely affected plants was stunted and wilted. The disease affected 5 ha and incidence was approximately 30%. Cream-colored bacterial colonies were isolated from surface disinfested symptomatic tissue that was macerated and streaked onto King's medium B (KMB) and sucrose peptone agar (SPA). Fungi were not recovered from any tissue that was surface disinfested and placed into acidified potato dextrose agar. Four representative strains were fluorescent on KMB and gram-negative based on lysis by KOH. Strains were positive for levan formation, negative for oxidase and arginine dihydrolase, and did not cause soft rot on potato slices but induced a hypersensitive response in tobacco (Nicotiana tabacum L. cv. Samsun); strains thus belonged to Lelliot's LOPAT group 1, P. syringae (3). All four strains had identical DNA fragment-banding patterns generated by repetitive extragenic palindromic sequence (rep)-PCR using the BOXA1R primer (4). The pattern generated was different than all P. syringae pathovars in genomospecies 1 including P. syringae pv. syringae. According to multilocus sequence analysis conducted by previously described methods, the strains are most closely related to P. syringae pv. aceris and P. syringae pv. solidagae in genomospecies 1 (1). Potted raspberry plants were used to test four strains for pathogenicity. Inoculum was prepared by growing the bacteria on SPA for 48 h and suspending the bacteria in sterile distilled water (SDW) for a final concentration of approximately 107 CFU/ml. Suspensions were sprayed until runoff onto three replicate plants per strain. Control plants were sprayed with SDW until runoff. Plants were enclosed in plastic bags for 24 h and then maintained in a greenhouse (23 to 25°C). After 7 to 8 days, water soaked lesions developed on all inoculated plants; lesions later turned dark brown and appeared similar to symptoms observed in the field. Plants treated with water developed no symptoms. Bacteria re-isolated onto KMB from symptomatic tissues were fluorescent and appeared identical to the bacteria used to inoculate the plants; two selected re-isolated strains were identical to the original strains according to rep-PCR, fluorescence, and LOPAT reactions. The experiment was repeated and disease development and recovery of fluorescent strains on KMB was identical to the first experiment. To our knowledge, this is the first report of Pseudomonas blight of raspberry, caused by P. syringae, in California. Affected plants initially were stunted in growth but later in the summer exhibited no lasting effects from the disease. Pseudomonas blight has been reported in the Pacific Northwest region of the United States, the British Columbia region of Canada, and Serbia (2). References: (1) C. T. Bull et al. Phytopathology 101:847, 2011. (2) Z. Ivanovic et al. Eur. J. Plant Pathol. 134:191, 2012. (3) R. A. Lelliott. J. Appl. Bacteriol. 29:470, 1966. (4) A. S. A. Marques, et al. Genet. Mol. Biol. 31:106. 2008.

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Park, Jeeyoung, Dirk Hengevoss e Stephen Wittkopf. "Industrial Data-Based Life Cycle Assessment of Architecturally Integrated Glass-Glass Photovoltaics". Buildings 9, n. 1 (29 dicembre 2018): 8. http://dx.doi.org/10.3390/buildings9010008.

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Abstract (sommario):

Worldwide, an increasing number of new buildings have photovoltaics (PV) integrated in the building envelope. In Switzerland, the use of coloured PV façades has become popular due to improved visual acceptance. At the same time, life cycle assessment of buildings becomes increasingly important. While a life cycle inventory for conventional glass-film PV laminates is available, this is not the case for glass-glass laminates, and in particular, coloured front glasses. Only conventional glass-film PV laminates are considered in databases, some of which are partly outdated. Our paper addresses this disparity, by presenting life cycle inventory data gathered from industries producing coloured front glass by digital ceramic printing and manufacturing glass-glass PV laminates. In addition, we applied this data to a hypothetical façade made of multi-coloured glass-glass laminates and its electricity generation in terms of Swiss eco-points, global warming potential, and cumulative energy demand as impact indicators. The results of the latter show that the effect of the digital ceramic printing is negligible (increase of 0.1%), but the additional glass (4% increase) and reduction of electricity yield (20%) are significant in eco-points. The energy pay-back time for a multi-coloured PV façade is 8.1 years, which decreases by 35% to 5.3 years when replacing the glass rain cladding in an existing façade, leaving 25 years for surplus electricity generation.

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30

Lee, Mordecai. "A Progressive Era Idea for Reforming Government that Didn’t Make It: Recall of Judicial Decisions". Public Voices 13, n. 1 (18 novembre 2016): 58. http://dx.doi.org/10.22140/pv.50.

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As a reform movement and an academic discipline, American public administrationgenerally coalesced during the Progressive era (1890-1920). Progressive reforms for the public sector seeped deeply into the DNA of the field, including separation of civil servants from politics, reliance on expertise, fewer elected offices, and public reporting of agency activities. However, not all of the governmental reforms proposed during this era were enacted. One of the most controversial and least known was Theodore Roosevelt’s proposal in 1912 that the voters be able to have a referendum on major court decisions, permitting them to overturn those decisions. His idea was only enacted in Colorado, where it remained on the books until 1921. This article reviews the original concept and its history in Colorado.

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31

Cinelli, T., D. Rizzo, G. Marchi e G. Surico. "First Report of Knot Disease Caused by Pseudomonas savastanoi on Sweet Olive in Central Italy". Plant Disease 97, n. 3 (marzo 2013): 419. http://dx.doi.org/10.1094/pdis-09-12-0818-pdn.

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In April 2012 the presence of hyperplastic outgrowths on trunks, branches, and twigs of sweet olive plants, Osmanthus fragrans Lour (Fam. Oleaceae), was recorded in two ornamental hedges made up of five and four plants, respectively, in the city center of Montecatini (Pistoia-Italy). All sweet olive plants were seriously affected by the disease with outgrowths appearing either singly or close together, often forming a single mass that could extend up to 20 cm along the stems, occasionally surrounding the entire circumference. The symptoms observed on O. fragrans closely resembled those induced by the bacterium Pseudomonas savastanoi on Olea europea (common olive) and other plant species. Suspecting a bacterial origin of the disorder, young knots were collected from four diseased plants and used for bacterial isolation with standard techniques on nutrient sucrose agar medium (1). After 3 days of incubation at 26°C, non-levan forming colonies about 3 mm in diameter that were circular, convex, smooth, and cream colored with entire margins appeared on the surface of the agar medium. Purified isolates were gram negative, levan negative, oxidase negative, potato rot negative, arginine dihydrolase negative, showed a tobacco hypersensitive reaction, and tested positive to PCR screening for the presence of the iaaM (tryptophan-2-monooxygenase), iaaH (indoleacetamide hydrolase), ptz (isopentenyl transferase) (1) and iaaL (IAA-lysine synthethase) (3) genes. Three isolates were selected arbitrarily and further characterized by sequencing a fragment of the housekeeping genes rpoD (sigma factor 70) and pgi (phosphoglucose isomerase) (2). All sequenced gene fragments, of 620 bp and 552 bp for the rpoD and pgi genes, respectively, were identical to those of P. savastanoi pv. savastanoi strain NCPPB3335. The pathogenicity of the three isolates was verified on three O. fragrans plants and three Olea europea (cv. Frantoio) plants. Per each isolate, three 1-cm wounds were made on the branches of each plant using a sterile scalpel dipped in a bacterial suspension (1 × 108 CFU/ml). P. savastanoi pv. savastanoi PVFi-t2b isolated from olive was also inoculated as reference strain. After 30 days, all isolates including the reference strain induced typical knots on both plant species while no symptoms were observed on wounds inoculated with sterile water. Bacteria were reisolated from induced knots and Koch's postulates were confirmed. On the basis of biochemical tests, PCR screening, pathogenicity testing, and sequence analyses, the causal agent of knot disease on O. fragrans was identified as P. savastanoi. The potential susceptibility of O. aquifolium Sieb. to the causal agent of olive knot disease has been demonstrated in the past by means of artificial inoculations but interestingly, in the same trials, O. fragrans had tested negative (4). To the best of our knowledge, this is the world's first report of O. fragrans as natural host of P. savastanoi, which extends the growing list of cultivated and ornamental plant species affected by this phytopathogenic bacterium. References: (1) G. Marchi et al. Eur J. Plant Pathol. 112:101, 2005. (2) N. Parkinson et al. Plant Pathol. 60:338, 2011. (3) R. Penyalver et al. Appl. Environ. Microbiol. 66:2673, 2000. (4) C. O. Smith. Phytopathology 12:271, 1922.

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32

Pravettoni, Mauro, Loris Manni e Sebastian Dittmann. "Light Emitting Diodes in the Experimental Practice for the Characterization of Novel Photovoltaics". MRS Proceedings 1771 (2015): 45–50. http://dx.doi.org/10.1557/opl.2015.367.

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ABSTRACTLight Emitting Diodes (LEDs) have recently gained importance in the experimental practice of photovoltaic (PV) devices. LEDs have already been proposed as the alternative to conventional xenon or halogen based solar simulators. Multi-junction PV devices use coloured LEDs in experimental tools as well: LEDs can transform a conventional solar simulator in a spectrally adjustable simulator for spectral characterization of multi-junction modules. Other useful applications include evaluating the dependence of the electrical parameters on the average photon energy and spectral responsivity measurements of multi-junction PV devices.

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Ganeva, Daniela, e Nevena Bogatzevska. "Sources of resistance to races R0 and R1 of Pseudomonas syringae PV. tomato - agent of bacterial speck on tomato". Genetika 49, n. 1 (2017): 139–49. http://dx.doi.org/10.2298/gensr1701139g.

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Tomato breeding lines with fruit colour different from the traditional red colour were studied in order to search for sources of resistance to races R0 and R1 of Pseudomonas syringae pv. tomato. As a result of selection of healthy plants with hypersensitive response (HR), the resistance was stabilized and perspective lines gene-carriers of resistance to bacterial speck were chosen. Lines L1078 and L1083 with brown-red (black) coloured fruits and line L1130 with purple-red fruits possess a complex resistance to races R0 and R1. It was established that two of the lines with rose-coloured tomato fruits (L1088 and L584) were resistant to race 1 of P. syringae pv. tomato. These lines possessed valuable economic and morphological characters and they could be used in combinative and heterosis breeding for development of resistance to bacterial speck varieties.

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34

Gent, David H., Jillian M. Lang, Michael E. Bartolo e Howard F. Schwartz. "Inoculum Sources and Survival of Xanthomonas axonopodis pv. allii in Colorado". Plant Disease 89, n. 5 (maggio 2005): 507–14. http://dx.doi.org/10.1094/pd-89-0507.

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Xanthomonas leaf blight, caused by the bacterium Xanthomonas axonopodis pv. allii, is an emerging disease of onion in the western United States and worldwide, but few management strategies have been developed because little is known about disease epidemiology and pathogen survival. Therefore, we sought to identify and quantify primary inoculum sources of the pathogen in Colorado. Growth chamber and field studies evaluated survival and dissemination of X. axonopodis pv. allii in association with weed, alternate host, and volunteer onion plants, irrigation water, and crop debris. Epiphytic X. axonopodis pv. allii was recovered from the foliage of nine asymptomatic weed species and Medicago sativa, but the bacterium was not recovered from plants in locations where an epidemic of Xanthomonas leaf blight did not occur the prior year. The bacterium also was isolated from volunteer onion with characteristic Xanthomonas leaf blight symptoms. A rifampicin mutant of X. axonopodis pv. allii strain O177 was recovered consistently from the irrigation tail water of onion fields inoculated with the bacterium; populations as large as 3.02 × 104 CFU/ml were recovered. X. axonopodis pv. allii was recovered from infested onion leaves 9 months after they were placed on the soil surface or buried to a depth of 25 cm, but culturable populations of the pathogen decreased 104 to 106 more in buried leaves. Cultural practices that avoid or eliminate X. axonopodis pv. allii inoculum sources should reduce Xanthomonas leaf blight losses to onion.

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35

Ibarra, Jorge, Jacob Snelling, Kathleen Alexander e Ned Tisserat. "Leaf Spotting of Turkish Filbert in Colorado Caused by Xanthomonas arboricola pv. corylina and Pseudomonas syringae pv. syringae". Plant Health Progress 13, n. 1 (gennaio 2012): 43. http://dx.doi.org/10.1094/php-2012-0517-01-br.

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Turkish filbert is a medium-sized tree native to southwest Asia and southeast Europe. It is well-adapted to urban settings, although its use as an ornamental in the United States has been limited. In 2010 and 2011, Turkish filberts at a site in Boulder, CO, exhibited leaf spotting, partial defoliation, and shoot dieback. Xanthomonas arboricola pv. corylina and Pseudomonas syringae pv. syringae were consistently isolated from leaf spots whereas X. arboricola pv. corylina was the only bacterium isolated from blight shoots. This is the first report of X. arboricola pv. corylina on Turkish Filbert in Colorado. Accepted for publication 7 March 2012. Published 17 May 2012.

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36

Hu, Yong Qiang, e Ming Yu Wang. "PV System Power Forecasting Based on Neural Network with Fuzzy Processing of Weather Factors". Advanced Materials Research 860-863 (dicembre 2013): 172–75. http://dx.doi.org/10.4028/www.scientific.net/amr.860-863.172.

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A short-term PV system power forecasting method is presented in the paper based on neural network considering fuzzy characteristics of weather factors. Weather factors that affect PV system power output mainly include temperature, radiation intensity, rain and relative humidity which are all of strong fuzziness. The paper firstly made use of membership functions to process their fuzziness. Then, the historical power data of a PV system was put into neural network together with fuzzy processed historical weather data to train the network, therefore, neural network that be able to forecast PV power was get. Finally, data of an actual PV system in Colorado was employed to methods with and without fuzzy processing of weather factors, results show that the method with fuzzy processing is more accurate than that without fuzzy processing.

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37

Gent, David H., e Howard F. Schwartz. "Effect of Nitrogen Fertilization and Seed Contamination on Epiphytic Populations of Xanthomonas axonopodis pv. allii and Development of Xanthomonas Leaf Blight of Onion". Plant Health Progress 6, n. 1 (gennaio 2005): 12. http://dx.doi.org/10.1094/php-2005-0331-01-rs.

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Abstract (sommario):

Xanthomonas leaf blight of onion, caused by Xanthomonas axonopodis pv. allii, is a yield-limiting disease in Colorado, for which few effective management strategies are available. The effects of rates of nitrogen fertilization and levels of seed contamination by X. axonopodis pv. allii on epiphytic populations of the pathogen and subsequent disease development were determined in field studies over two years. Epiphytic populations of a rifampicin-resistant mutant were quantified from bulked, asymptomatic leaf tissue using a leaf wash assay. There was no significant relationship between nitrogen fertilization treatment and epiphytic population development, but excessive nitrogen (> 200 kg/ha) fertilization increased disease severity 27 to 50% compared with non-fertilized and low (112 kg/ha) nitrogen fertilizer treatments in 2004. Seed inoculated with various levels of X. axonopodis pv. allii did not result in persistent epiphytic populations of the bacterium or development of symptoms, even at 107 CFU/g of seed. The results of these studies suggest moderate rates of nitrogen fertilization may reduce severity of Xanthomonas leaf blight compared to higher rates, and that seed contamination by X. axonopodis pv. allii may be of limited importance for disease development under the semi-arid conditions of furrow-irrigated onion production in Colorado. Accepted for publication 13 March 2005. Published 31 March 2005.

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38

Moretti, C., R. Fakhr e R. Buonaurio. "Calendula officinalis: A New Natural Host of Pseudomonas viridiflava in Italy". Plant Disease 96, n. 2 (febbraio 2012): 285. http://dx.doi.org/10.1094/pdis-08-11-0691.

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In November 2010, small necrotic spots surrounded by chlorotic halos, which sometimes enlarged and coalesced to form large dead areas, were observed on leaves of marigold (Calendula officinalis L.) plants grown in the Medieval Garden at the Agricultural Faculty of Perugia (central Italy). Cream-colored bacterial colonies were consistently isolated on nutrient agar (NA) from the diseased leaf tissues. Four representative selected strains, which were gram negative, fluorescent on King's medium B, and had oxidative but not fermentative metabolism, were subjected to a pathogenicity test by inoculating 1-month-old marigold plants. To prepare the inoculum, the bacterial strains were grown on NA at 27°C for 24 h, suspended in sterile deionized water, and adjusted to 1 × 106 CFU/ml. Sterile water was used for control plants. Marigold leaves were infiltrated with a glass atomizer at high pressure, and plants were kept in a growth chamber at 22 to 24°C, 70 μE·m–2·s–1 illumination and 12-h light period, and 80% relative humidity. Small, water-soaked necrotic spots were observed 10 days after inoculation, and the bacterium with the same cultural features of the original strains was reisolated from inoculated plants. For bacterial identification, the four original strains and two reisolates were subjected to LOPAT tests. They were levan negative, oxidase negative, potato rot positive, arginine dihydrolase negative, and tobacco hypersensitive response positive. These results were similar to those obtained with the type strain LMG 2352T of Pseudomonas viridiflava (Burkholder) Dowson. When 16S rDNA was amplified with the universal primers, P0 (6-27f Escherichia coli) and P6 (1515-1495r E. coli), and digested with the endonucleases, SacI and HinfI as previously reported (2), an identical restriction profile was obtained for marigold strains and reisolates and P. viridiflava strains, LMG 2352T, LMG 2353, LMG 5397, and NCPPB 1382. A completely different profile was obtained for P. syringae pv. syringae LMG 1247T. The 16S rDNA (1,364 bp) and the gyrB (570 bp) sequences of two selected marigold strains (GenBank Accession Nos. JN406504 and JN406505; JN406506 and JN406507), amplified by using universal and previously reported PCR primers (3), respectively, shared 100% sequence identity with P. viridiflava (GenBank Accession Nos. HM190229 and AY606763) for 16S rDNA and gyrB gene, respectively. On the basis of biochemical, physiological, molecular, and pathogenicity tests, it was concluded that the bacteria isolated from marigold leaves are P. viridiflava. To our knowledge, this is the first report of C. officinalis as a natural host of P. viridiflava. The plant was previously reported as a host of the bacterium by artificial inoculation (1). References: (1) J. F. Bradbury. Guide to Plant Pathogenic Bacteria. CAB International, Egham, UK, 1986. (2) A. J. González et al. Appl. Environ. Microbiol. 69:2936, 2003. (3) E. M. Goss et al. Genetics 169:21, 2005.

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Gent, David H., Jillian M. Lang e Howard F. Schwartz. "Epiphytic Survival of Xanthomonas axonopodis pv. allii and X. axonopodis pv. phaseoli on Leguminous Hosts and Onion". Plant Disease 89, n. 6 (giugno 2005): 558–64. http://dx.doi.org/10.1094/pd-89-0558.

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Xanthomonas leaf blight of onion (Allium cepa), caused by Xanthomonas axonopodis pv. allii, and common bacterial blight of dry bean (Phaseolus vulgaris), caused by Xanthomonas axonopodis pv. phaseoli, are perennial problems in the Central High Plains of the United States. Onion and dry bean are commonly grown in rotation in Colorado, but it is unknown if X. axonopodis pv. allii and X. axonopodis pv. phaseoli survive epiphytically or pathogenically on dry bean and onion, respectively. Under high humidity growth chamber conditions, epiphytic X. axonopodis pv. allii populations increased on alfalfa, chickpea, dry bean, lentil, and soybean, but the epiphytic populations were at least 10-fold greater on onion. When artificially inoculated under field conditions, epiphytic populations of X. axonopodis pv. allii were recovered from dry bean, lentil, and onion, but the bacterium did not persist on chickpea or soybean. Epiphytic X. axonopodis pv. phaseoli was recovered from symptomless onion plants in fields cropped to dry bean the prior year, but not from fields cropped to a host other than dry bean. Close rotation of onion and dry bean may allow X. axonopodis pv. allii and X. axonopodis pv. phaseoli to persist epiphytically, and crop rotation schemes may need to be altered to reduce survival of these pathogens in onion and dry bean cropping systems.

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Šujanová, Paulína, e Jozef Hraška. "Measurement and Calculation of Luminous Characteristics of Photovoltaic Glazing Samples". Applied Mechanics and Materials 824 (gennaio 2016): 724–31. http://dx.doi.org/10.4028/www.scientific.net/amm.824.724.

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Photovoltaic glazing is a relatively novel type of glazing material, suitable for application in nearly-zero energy buildings. As a special type of building integrated photovoltaic (BIPV), it generates energy from solar radiation and ensures the performance characteristics of building envelope. This paper presents a combined approach of evaluation of luminous characteristics of glazing based on photopic and circadian action spectra. Measurements were performed on 6 photovoltaic glazing samples with amorphous silicon solar cells. The samples differ in type of spacing and rear glazing colour. The results have shown that PV glazing with coloured glazing should be used with caution, especially in rooms with high daylighting requirements. Obtained results can be used during designing process to evaluate impact of PV glazing on visual comfort.

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41

Pelle, Martina, Elena Lucchi, Laura Maturi, Alexander Astigarraga e Francesco Causone. "Coloured BIPV Technologies: Methodological and Experimental Assessment for Architecturally Sensitive Areas". Energies 13, n. 17 (1 settembre 2020): 4506. http://dx.doi.org/10.3390/en13174506.

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Energy flexibility in buildings is gaining momentum with the introduction of new European directives that enable buildings to manage their own energy demand and production, by storing, consuming or selling electricity according to their need. The transition towards a low-carbon energy system, through the promotion of on-site energy production and enhancement of self-consumption, can be supported by building-integrated photovoltaics (BIPV) technologies. This paper investigates the aesthetic and technological integration of hidden coloured PV modules in architecturally sensitive areas that seem to be the best possibility to favour a balance between conservation and energy issues. First, a multidisciplinary methodology for evaluating the aesthetic and technical integration of PV systems in architecturally sensitive area is proposed, referring to the technologies available on the market. Second, the experimental characterisation of the technical performance specific BIPV modules and their comparison with standard modules under standard weather condition are analysed, with the aim of acquiring useful data for comparing the modules’ integration properties and performance. For this purpose, new testbeds have been set up to investigate the aesthetic integration and the energy performances of innovative BIPV products. The paper describes the analyses carried out to define the final configuration of these experimental testbeds. Finally, the experimental characterisation at standard test conditions of two coloured BIPV modules is presented and the experimental design for the outdoor testing is outlined.

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42

Agarkova, I. V., P. A. Lambrecht, A. K. Vidaver e R. M. Harveson. "Genetic diversity among Curtobacterium flaccumfaciens pv. flaccumfaciens populations in the American High Plains". Canadian Journal of Microbiology 58, n. 6 (giugno 2012): 788–801. http://dx.doi.org/10.1139/w2012-052.

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Curtobacterium flaccumfaciens pv. flaccumfaciens is a Gram-positive bacterium and has reemerged as an incitant of bacterial wilt in common (dry, edible) beans in western Nebraska, eastern Colorado, and southeastern Wyoming. Curtobacterium flaccumfaciens pv. flaccumfaciens is diverse phenotypically and genotypically and is represented by several different pathogen color variants. The population structure of 67 strains collected between 1957 and 2009, including some isolated from alternate hosts, was determined with 3 molecular typing techniques: amplified fragment length polymorphism (AFLP), repetitive extragenic palindromic polymerase chain reaction (rep-PCR), and pulsed-field gel electrophoresis (PFGE). All 3 typing techniques showed a great degree of population heterogeneity, but they were not congruent in cluster analysis of the C. flaccumfaciens pv. flaccumfaciens populations. Cluster analysis of a composite data set (AFLP, PFGE, and rep-PCR) using averages from all experiments yielded 2 distinct groups: cluster A included strains with colonies of yellow, orange, and pink pigments, and cluster B had strains of only yellow pigment. Strains producing purple extracellular pigment were assigned to both clusters. Thus, C. flaccumfaciens pv. flaccumfaciens is diverse phenotypically and genotypically.

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43

Zumbado Gutiérrez, Leana, e Juan José Romero Zúñiga. "Factores asociados a la contaminación con Campylobacter spp. termotolerante en pollos de engorde, en tres niveles de la cadena avícola, para consumo humano en Costa Rica." Revista Ciencias Veterinarias 34, n. 2 (14 gennaio 2017): 81. http://dx.doi.org/10.15359/rcv.34-2.2.

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Campylobacter spp. es una bacteria destacada por ser causa frecuente de infecciones transmitidas por alimentos, tanto en países desarrollados como en vías de desarrollo. Se realizó un estudio transversal, entre marzo y julio del 2015, con el fin de obtener la prevalencia nacional de Campylobacter spp. en pollo de engorde para consumo humano. Se utilizó un diseño de muestreo simultáneo en tres niveles de la cadena productiva avícola costarricense: 152 muestras en granja (CC), 104 en planta (CA) y 96 en puntos de venta (PV). Se elaboró formularios de variables asociadas al manejo en las plantas (CC y CA) y los PV. Los formularios, en las plantas, incluyeron variables relacionadas con datos generales como: ubicación y volumen de producción, buenas prácticas higiénicas y de manufactura (BPHM), procesos, y HACCP. En PV se evaluó aspectos relacionados con BPHM, temperatura del producto, y precio por kg de pollo limpio, entre otros. Se determinó como factores de riesgo los siguientes: tiempo de espera de animales vivos en andén > 60 minutos (RP = 2.28, IC 95% 1.23-4.21); velocidad de proceso <120 aves/min (RP=1.51, IC95% 1.09-2.10); temperatura del agua del chiller ≤0.5ºC (RP 1.60, IC95% 1.18-2.17); sin separación física entre matrices de diferente origen animal en PV (RP=1.78, IC95% 1.43-2.20) y precio en PV ≤2000 colones/kg de pollo limpio (RP=1.73, IC95% 1.21-2.46). La prevalencia encontrada de Campylobacter spp. es alta. Representa un peligro para la salud pública en Costa Rica. Por tal motivo, se debe implementar intervenciones bactericidas más eficientes contra este agente y mejorar las BPHM en cada eslabón de la cadena de producción.

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44

Arias, Silvina L., Charles C. Block, Derrick A. Mayfield, Gem Santillana, Michael J. Stulberg, Kirk D. Broders, Tamra A. Jackson-Ziems e Gary P. Munkvold. "Occurrence in Seeds and Potential Seed Transmission of Xanthomonas vasicola pv. vasculorum in Maize in the United States". Phytopathology® 110, n. 6 (giugno 2020): 1139–46. http://dx.doi.org/10.1094/phyto-08-19-0306-r.

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This paper reports original evidence regarding the potential role of seed transmission of Xanthomonas vasicola pv. vasculorum in the epidemiology of bacterial leaf streak (BLS) in maize. We evaluated the occurrence of the pathogen on seeds from diseased fields and its subsequent transmission to seedlings. In 2016 and 2017, X. vasicola pv. vasculorum was detected by TaqMan PCR from 22 of 41 maize seed lots harvested from naturally infected fields in Colorado, Nebraska, and Iowa. However, many of the PCR-positive samples did not yield culturable X. vasicola pv. vasculorum colonies. The highest levels of seed contamination were detected in dent maize and popcorn from NE and CO. Seed transmission was evaluated in greenhouse grow-outs from eight seed lots, totaling more than 14,000 plants. Putative seed transmission events from naturally contaminated seed lots, estimated from PCR results, occurred at a frequency between 0.1 and 0.5% in 10-seedling pooled samples and at a frequency of 2.7% from individual plant assays. However, no seedling symptoms were observed during these assays and live X. vasicola pv. vasculorum colonies were not recovered from PCR-positive seedlings. In contrast, seed transmission was readily demonstrated from artificially contaminated seed lots, including typical symptoms and recovery of live bacteria. Seed transmission consistently occurred from seeds soaked in bacterial suspensions with concentrations of ≥106 CFU/ml, suggesting that a threshold population of the bacterium is necessary for the development of BLS symptoms and recovery of live bacteria. The low bacterial populations on naturally contaminated seeds apparently were not sufficient to result in diseased seedlings.

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45

Carvajal, A. M., M. E. Martínez e R. De la Barra. "Estructura y diversidad de razas bovinas en Patagonia verde". Archivos de Zootecnia 70, n. 270 (15 aprile 2021): 178–84. http://dx.doi.org/10.21071/az.v70i270.5470.

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Patagonia Verde (PV) corresponde a un territorio del sur de Chile moldeado por un clima y geografía agrestes que hacen patente el requerimiento de biotipos bovinos muy bien adaptados. Tradicionalmente se han utilizado como reproductores bovinos Hereford y cruzas con Overo Colorado, pero sin realizarse evaluaciones genéticas de la progenie. Por tanto, en miras de establecer un programa de mejoramiento se requiere conocer el estado de los rebaños en términos de su pureza racial. El objetivo de este trabajo fue obtener información acerca de la distribución y estructura de los rebaños bovinos presentes en PV. La identificación de los biotipos o razas se realizó mediante observación directa de cada animal evaluando sus descriptores raciales. Se incluyeron animales de cualquier edad y sexo, y aquellos pobremente diferenciados o con mezclas en sus descriptores fueron clasificados como híbridos. El análisis y caracterización de los rebaños se realizó mediante clusterización aglomerativa jerárquica de forma de identificar patrones en la estructura de rebaño. La composición de cada clúster fue analizada mediante estadística descriptiva y las diferencias entre los biotipos y su distribución mediante ANOVA y test de Fisher LSD (p

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46

Urrea, Carlos A., e Robert M. Harveson. "Identification of Sources of Bacterial Wilt Resistance in Common Bean (Phaseolus vulgaris)". Plant Disease 98, n. 7 (luglio 2014): 973–76. http://dx.doi.org/10.1094/pdis-04-13-0391-re.

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Abstract (sommario):

Over the last decade, bacterial wilt, caused by Curtobacterium flaccumfaciens pv. flaccumfaciens, has reemerged in the Central High Plains (Nebraska, Colorado, and Wyoming) and has been identified in almost 500 fields. Affected fields were planted with bean (Phaseolus vulgaris) from multiple market classes and seed sources, including yellow, great northern, pinto, kidney, cranberry, black, navy, pink, and small red, and incidence varied from trace levels to >90%. One wilt-resistant bean, ‘Emerson’, is available today but it is grown on a limited basis as a specialized cultivar for targeted markets in Europe and cannot be grown in all fields where the disease has recently been identified. Thus, we are faced with an emerging problem that must be addressed by utilizing newly developed resistant cultivars. This study was initiated to evaluate the Phaseolus National Plant Germplasm System (NPGS) bean collection for resistance to C. flaccumfaciens pv. flaccumfaciens in the ongoing effort to develop a new wilt-resistant cultivar adapted to this region. In total, 467 entries, including accessions from the NPGS, several commercial great northern and pinto cultivars, and University of Nebraska experimental lines, were screened with a highly virulent orange strain of C. flaccumfaciens pv. flaccumfaciens previously recovered from an infected great northern bean plant in Nebraska. Bacterial wilt severity ratings were 1.0 to 9.0 (0 to 90% incidence). Of the 427 accessions from the NPGS, only 1 showed resistance (0.23%), 19 showed intermediate resistances (4.45%), and the remainder were susceptible (95.34%). PI 325691 was identified as a source of bacterial wilt resistance. It was screened against six additional C. flaccumfaciens pv. flaccumfaciens strains and still produced resistant reactions. PI 325691 is a wild common bean (P. vulgaris) collected 8 miles South of Tzitzio, Michoacán, Mexico; however, it has a small seed size (5.3 g 100−1 seeds) that is commercially unacceptable. It will take several backcrosses to transfer this resistance to bacterial wilt and recover the seed size into a cultivated bean.

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Uchanski, Mark, Thomas Hickey, Jennifer Bousselot e Kurt L. Barth. "Characterization of Agrivoltaic Crop Environment Conditions Using Opaque and Thin-Film Semi-Transparent Modules". Energies 16, n. 7 (25 marzo 2023): 3012. http://dx.doi.org/10.3390/en16073012.

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Abstract (sommario):

Agrivoltaics (APV), the co-location of agriculture and photovoltaics (PV), addresses an inherent competition for land usage. Taking the same dual-use concept to the urban landscape, rooftop APV can provide locally grown food in areas of need while providing distributed energy generation. In this multi-year investigation, different APV plots in northern Colorado, USA, were studied for crop metrics, light transmission, air temperature, soil/substrate temperature and moisture. Crops were grown under different solar panel types including opaque silicon and opaque and semi-transparent (ST) thin-film CdTe technologies. Growth conditions were characterized showing generally improved conditions and moderated temperatures under the panels. The ST-CdTe panels had increased photosynthetically active radiation (PAR) compared to both opaque panel types without a significant corresponding increase in temperature.

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48

Couty, Philippe, e Christophe Arn. "SmarSolar : PV production forecast used by the Swiss team, winner of the U.S. Department of Energy Solar Decathlon competition 2017 Denver, Colorado". Journal of Physics: Conference Series 1343 (novembre 2019): 012091. http://dx.doi.org/10.1088/1742-6596/1343/1/012091.

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49

Caddick, Mark X., Alan G. Brownlee e Herbert N. Arst. "Phosphatase regulation inAspergillus nidulans: responses to nutritional starvation". Genetical Research 47, n. 2 (aprile 1986): 93–102. http://dx.doi.org/10.1017/s0016672300022916.

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SUMMARYThe regulation of the syntheses of a number of phosphatases in the fungusAspergillus nidulanshas been examined. Levels of the intracellular alkaline phosphatase P11 are increased by starvation for carbon, nitrogen, phosphorus or sulphur. There is, however, no evidence that any of the wide domain regulatory genes which mediate sufficiency-triggered repression for each of these elements involved. A possible interpretation is that all four forms of starvation result in accumulation of an inducing metabolite. ThepalcA gene has been identified as a wide domain, probably positive-acting regulatory gene mediating phosphate repression. ThepalcA product controls the syntheses of alkaline phosphatase PI, acid phosphatases PIII and PV, a phosphodiesterase lacking phosphomonoesterase activity and probably also a phosphate permease. Mutations resulting in derepression of phosphate-repressible activities at acid but not alkaline growth pH define a gene designatedpacJ.pacJ mutations also confer arsenate resistance at low but not high pH. It is likely that phosphate derepression and arsenate resistance result from reduced uptake of H2PO4−. Finally, phosphatase regulation might be less complex than previously thought. Mutations designatedrand mapping at several loci apparently have no effect on phosphatase. They enhance phosphatase colony staining but this occurs even if the phosphatase substrates are omitted from the staining mixtures.rmutations appear to promote reactions converting the diazonium salts used for phosphatase staining to coloured precipitates.

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Harveson, R. M., H. F. Schwartz, A. K. Vidaver, P. A. Lambrecht e K. L. Otto. "New Outbreaks of Bacterial Wilt of Dry Bean in Nebraska Observed from Field Infections". Plant Disease 90, n. 5 (maggio 2006): 681. http://dx.doi.org/10.1094/pd-90-0681a.

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Bacterial wilt caused by Curtobacterium flaccumfaciens pv. flaccumfaciens was one of the more problematic diseases of dry bean (Phaseolus vulgaris L.) throughout the irrigated High Plains (Colorado, Nebraska, and Wyoming) in the 1960s and early 1970s, but has not been observed since that time. However, in August of 2003, plants exhibiting wilting and irregular, interveinal necrotic foliar lesions surrounded by a bright yellow border were found in three dry bean fields (market class Great Northern) in Scotts Bluff County, Nebraska. During 2004, plants exhibiting identical symptoms were additionally found occurring in more than 40 dry bean fields in western Nebraska. Affected fields were planted with dry bean from multiple market classes and seed sources, including yellow bean, Great Northern bean, and pinto bean, and incidence varied from trace levels to 80 to 90%. Isolations were made from leaf and stem tissues and seeds collected after harvest from infected plants, and all yielded slow-growing, creamy yellow or orange, fluidal colonies on nutrient broth-yeast extract medium. The bacterium was identified as C. flaccumfaciens pv. flaccumfaciens based on cell morphology (coryneformshaped motile rods), positive Gram stain and KOH reactions, fatty acid profiles, and BIOLOG (Hayward, CA) identifications. Great Northern (cv. Orion) plants were inoculated by bacterial suspensions (5 × 107 CFU/ml) injected into leaf axils adjacent to the first fully expanded trifoliolate and were incubated in the greenhouse under ambient conditions fluctuating between 24 and 35°C. Wilting symptoms developed 7 days after inoculation with foliar necrosis and yellowing symptoms appearing after 24 days. Identical bacterial colonies were reisolated from inoculated tissues, completing Koch's postulates. Although recent reports of wilt have been made in North Dakota (2) and western Canada (1) in 1995 and 2002, respectively, they were based only on the presence of discolored seeds observed in dockage from processing plants after harvest. To our knowledge, this report represents the first widespread observations of bacterial wilt from field infections in Nebraska in more than 30 years. References: (1) J. R. Venette et al. Plant Dis. 79:966, 1995. (2) T. F. Hsieh et al. Plant Dis: 86:1275, 2002.

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