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Du, Cheng Bin, Wei Qing Chen, and Fa Xue Wan. "Influence of HLB Parameters of Surfactants on Properties of Magneto-Rheological Fluid." Advanced Materials Research 97-101 (March 2010): 843–47. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.843.
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The hydrophilic-lipophilic balance (HLB) parameters of surfactants have a significant effect on properties of surfactants and determine the effects of surfactants. The magneto-rheological fluid (MRF) is prepared by using the two typical HLB parameters of surfactants including Polyethylene Glycol and oleic acid in order to improve the property of MRF. Polyethylene Glycol (PEG) whose HLB parameter is 20 has strong hydrophilic. Oleic acid whose HLB parameter is 1 has strong lipophilic. The results indicate that magnetic properties of magnetic particles and rheological properties of MRF can hardly be changed by adding surfactants. The sedimentary stability of MRF adding lipophilic surfactants is superior to that of MRF adding hydrophilic surfactants, and the stability of MRF adding two surfactants increases significantly.
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Zapolski, Remigiusz, Monika Gasztych, Beata Jastrząb-Miśkiewicz, Alina Jankowska-Konsur, and Witold Musiał. "The Properties of the Monolayers of Sorbitan Lipids as Informative Factors on the Hydrophilic–Lipophilic Balance Value of Their Mixtures, Proposed for Dermatological Applications." Molecules 30, no. 8 (2025): 1841. https://doi.org/10.3390/molecules30081841.
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This study investigates the correlation between the hydrophilic–lipophilic balance (HLB) values and the π–A isotherm parameters of surfactant monolayers composed of sorbitan esters, specifically sorbitan monopalmitate, sorbitan tristearate, sorbitan monooleate, and sorbitan sesquioleate. The surfactant mixtures were prepared, and their π-A isotherms were recorded. The HLB values calculated for each mixture were in the range 2.10–6.70. The HLB values were compared to compression parameters, including the ratios of the slopes and the ratios of the intercepts, which were between 0.19 and 4.00 and between 0.64 and 1.77, respectively, across the monolayer compression stages. The findings indicate a significant relationship between HLB values and isotherm parameters, particularly for systems with sorbitan monooleate and sorbitan sesquioleate. A value of determination coefficient of 0.95 was found for the linear equation representing the slope ratios as a function of HLB, whereas the intercept ratios, as a linear function of HLB, gave a lower value of 0.71. The results allow for the use of the π–A Langmuir isotherm to experimentally estimate the value of the HLB in mixtures of the sorbitol esters of fatty acids, whose value is an important parameter in the selection of optimized topical and transdermal formulations, highlighting the specific formulations that enhance active substance delivery while minimizing skin irritation potential.
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Ranjan, Das. "Modulation of the proton transfer dynamics of a 3-hydroxychromone dye in nonionic micelles : The role of the hydrophile-lipophile balance parameter." Journal of Indian Chemical Society Vol. 90, Aug 2013 (2013): 1093–103. https://doi.org/10.5281/zenodo.5785501.
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Department of Chemistry, West Bengal State University, Barasat, Kolkata-700 126, India <em>E-mail:</em> ranjan.das68@gmail.com Fax : 91-33-25241977 <em>Manuscript received online 19 July 2012, revised 21 August 2012, accepted 22 August 2012</em> The photo physics of 2-(2<em>' </em>-furyl)-3-hydroxychromone (FHC) was explored in three different non-ionic micelles of Triton X-100, Brij-58 and Tween-20. FHC exhibits a dual emission, attributable to the excited normal (N<strong>*</strong>) and tautomer (T<strong>*</strong>) forms resulting from an excited state intramolecular proton transfer (ESIPT) reaction (N<strong>*→</strong>T<strong>*</strong>). The ESIPT dynamics of FHC in the non-ionic micelles demonstrates a dependence on the hydrophile-lipophile balance (HLB) parameter of the surfactants by an increase in the kinetic constant of ESIPT reaction (<em><sup>k</sup></em>PT) with a decrease in HLB. A comparison of the difference in positions of the N<strong>*</strong> and T<strong>*</strong> band maxima, (V<sub>N</sub><strong><sub>*</sub> </strong>- V<sub>T*</sub>), between the micelles and polar protic solvents indicates to location of the dye in the polar palisade layer of the non-ionic micelles, which were further corroborated from the time-resolved anisotropy measurements. The slowest ESIPT dynamics in Tween-20 among the three non-ionic micelles is attributed to its relatively stronger hydration than others, and originates from its highest HLB value of 16.7, whereas a weaker hydration owing to a lower HLB value of 13.5 leads to the fastest proton-transfer dynamics in Triton X-100. However, in addition to the lower HLB value of its constituent surfactants, weaker hydration of the Triton X-100 micelles than the other two may originate from a weaker micelle-water interaction due to its more rigid environment.
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Smejkal, Gary, Vera Gross, and Alexander Lazarev. "Theoretical and Experimental Determinations of the Hydrophilic–Lipophilic Balance (HLB) of Representative Oils and Lecithins." Colloids and Interfaces 8, no. 2 (2024): 21. http://dx.doi.org/10.3390/colloids8020021.
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The hydrophilic–lipophilic balance (HLB) is a valuable parameter used to determine the relative hydrophobicity of a compound based on its chemical structure. This semi-empirical parameter has been instrumental in formulating oil-in-water and water-in-oil emulsions using well-characterized ingredients with known HLB values. However, recent trends toward the use of minimally processed “virgin” oils of therapeutic or nutritional value may render the reported “required HLB” values inaccurate. Minimally processed oils can contain numerous compounds at varying or unknown concentrations, rendering the HLB value incalculable. Factors such as regional source, growing season, and processing method contribute to the variability in oil composition. Furthermore, the solubilization of lipophilic bioactives in oils can significantly alter the HLB of the oil phase in a concentration-dependent manner. This complicates the formulation of emulsions, as the HLB values of both the oil phase and emulsifiers must be closely matched to achieve stable formulations. This study presents a simple and efficient experimental method to determine an HLB value of a complex ingredient without resorting to lengthy Design-of-Experiment (DoE) matrices and trial-and-error approaches. The optimal HLB of a formulation can be determined from a series of experiments in which two well-characterized surfactants of known HLB values are mixed at varying proportions with an unknown oil phase, where the HLB of the oil is considered to match the HLB value of the surfactants combined at the proportion at which nanoemulsions with the smallest, most stable oil droplets are formed. Similarly, when the HLB values of the oil phase and other contributing components are precisely known, the unknown HLB of a complex natural surfactant can be calculated. These calculations assist in formulating emulsions efficiently and effectively by ensuring optimal compatibility among all the components.
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Tubtimsri, Sukannika, Chutima Limmatvapirat, Pornsak Sriamornsak, and Sontaya Limmatvapirat. "Determination of Required Hydrophile-Lipophile Balance Value of Modified Coconut Oil." Advanced Materials Research 1060 (December 2014): 172–75. http://dx.doi.org/10.4028/www.scientific.net/amr.1060.172.
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Hydrophile–lipophile balance (HLB) is a key parameter for formulation of emulsions. Recently, modified coconut oil (MCO) was successfully developed as antimicrobial oil and was attempted to use as active ingredient in emulsions. Therefore, the aim of this study was to determine the required HLB of MCO. The emulsions was produced with different ratios of emulsifier mixtures of Tween® 80 and Span® 80 , giving HLB from 4.3 to 15.0 and was investigated in respect of their emulsions stability. The result showed that an emulsion with HLB value of 12 demonstrated the most stable in terms of smallest droplet size and minimal size distribution. The stability was also later confirmed by centrifugation and temperature cycling. The emulsions which possessed HLB values closed to required HLB demonstrated minimal creaming and cracking upon accelerated stability study. In conclusion, this study could provide the guideline for formulation of the stable MCO emulsions which may be further developed into suitable dosage form.
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Zuhran, M., Gatot Mudjiono, and Retno Dyah Puspitarini. "The Effect of Citrus Farming Practices on Huanglongbing (HLB) Disease Severity in Sambas, West Kalimantan." Jurnal Hortikultura Indonesia 12, no. 2 (2021): 108–16. http://dx.doi.org/10.29244/jhi.12.2.108-116.
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Beberapa praktik budidaya dilaporkan mempengaruhi kesesuaian agroekosistem bagi perkembangan penyakit tanaman. Namun demikian, praktik-praktik budidaya jeruk yang mempengaruhi perkembangan penyakit huanglongbing (HLB) dan serangga vektornya yaitu kutu loncat jeruk (KLJ) Diaphorina citri belum banyak diketahui. Penelitian ini mempelajari pengaruh praktik budidaya jeruk terhadap intensitas penyakit HLB melalui survei singkat selama dua minggu pada 37 kebun jeruk yang berlokasi di Kabupaten Sambas. Parameter pengamatan adalah intensitas serangan penyakit HLB, kelimpahan KLJ, dan praktik budidaya yang diterapkan. Pengaruh praktik budidaya terhadap intensitas serangan penyakit HLB dianalisis melalui structural equation modeling berbasis partial least squares (SEM-PLS). Hasil penelitian menunjukkan tingkat penggunaan pestisida, kualitas saluran drainase, dan kepadatan tanaman jeruk berpengaruh positif terhadap intensitas serangan penyakit HLB, sedangkan tingkat keanekaragaman vegetasi dan pemberian pupuk kimia berpengaruh negatif terhadap intensitas serangan penyakit HLB. Pengendalian gulma, kualitas tanah, dan pemangkasan pemeliharaan tidak mempengaruhi intensitas HLB. Oleh karena itu, penanaman jeruk sebaiknya menerapkan sistem polikultur, menggunakan beragam varietas, dan jarak tanam tidak terlalu rapat. Pemberian hara yang dapat meningkatkan ketahanan tanaman jeruk terhadap serangan KLJ hendaknya ditingkatkan. Pengendalian hama dan penyakit tanaman disarankan dilakukan secara terpadu sehingga insektisida hanya digunakan ketika populasi hama mencapai ambang ekonomi.
 Kata kunci: huanglongbing, jeruk, kutu loncat jeruk, praktik budidaya
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Fang, Qingchao, Xin Zhao, Sunbo Li, Zhengsong Qiu, Zhiyuan Wang, and Qi Geng. "Effect of Surfactants with Different Hydrophilic–Lipophilic Balance on the Cohesive Force between Cyclopentane Hydrate Particles." Journal of Marine Science and Engineering 10, no. 9 (2022): 1255. http://dx.doi.org/10.3390/jmse10091255.
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Effective control of the cohesive force between hydrate particles is the key to prevent their aggregation, which then causes pipeline blockage. The hydrophilic–lipophilic balance (HLB) value of surfactants was proposed as an important parameter for the evaluation and design of hydrate anti-agglomerants. A microscopic manipulation method was used to measure the cohesive forces between cyclopentane hydrate particles in the presence of Tween and Span series surfactants with different HLB values; moreover, the measured cohesive force was compared with the results of calculations based on the liquid bridge force model. Combined with the surface morphology and wettability of the hydrate particles, we analyzed the mechanism by which surfactants with different HLB values influence the cohesion between hydrate particles. The results show that for both Tween (hydrophilic, HLB > 10) and Span (hydrophobic, HLB < 10) surfactants, the cohesive force between cyclopentane hydrate particles decreased with decreasing HLB. The experimental results were in good agreement with the results of calculations based on the liquid bridge force model. The cohesive force between hydrate particles increased with increasing concentration of Tween surfactants, while in the case of the Span series, the cohesive force decreased with increasing surfactant concentration. In the formation process of cyclopentane hydrate particles, the aggregation of low-HLB surfactant molecules at the oil–water or gas–water interface increases the surface roughness and hydrophobicity of the hydrate particles and inhibits the formation of liquid bridges between particles, thus reducing the cohesion between particles. Therefore, the hydrate aggregation and the associated blockage risks can be reduced.
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Flores-Sánchez, J. L., G. Mora-Aguilera, E. Loeza-Kuk, et al. "Diffusion Model for Describing the Regional Spread of Huanglongbing from First-Reported Outbreaks and Basing an Area Wide Disease Management Strategy." Plant Disease 101, no. 7 (2017): 1119–27. http://dx.doi.org/10.1094/pdis-04-16-0418-re.
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Huanglongbing (HLB), a recent worldwide spreading disease on citrus, was detected in July 2009 in Yucatan State of Mexico. The objective of this study was to evaluate the fit of diffusion and classic disease gradient models to large-scale HLB spatial data originated from initial foci to improve sampling, monitoring, and control strategies for Diaphorina citri, vector of Candidatus Liberibacter asiaticus (CLas), putative agent of HLB. Four transect routes were selected: Yuc-1, Yuc-2, QRoo-1, and QRoo-2, based on the directionality of the prevailing winds and foci location of HLB infected plants. In these routes, 35 sites, 5 to 20 km apart, were selected for monthly evaluation during a 12-month period. A 10-insect sample and disease incidence and severity of HLB, further confirmed by PCR, were assessed per site. Mexican lime was more vulnerable (67.5%) than sweet orange (14%). Also, leaf symptoms were mostly found with homogeneous distribution but rarely reaching 100% of the tree canopy during the 12-month period. The diffusion model provided the best fit among the family of time-gradient curves (r2 = 0.90 to 0.99) due to the flexibility of a three-parameter model. The gradients were well conformed to the model in a 25 to 82.6 km range, having the east-west direction the longest effect. Yuc-2 and QRoo-2 transects showed 82.6 and 43.9 km gradients with a diffusion coefficient (Do) of 0.15 and 0.09, respectively. This study constitutes the first quantitative evidence of the regional spread of CLas from a single focus and the application of a flexible model that improved the fit and allowed to better compare different gradients. These results are useful to determine the size of Regional Areas of Diaphorina citri Control (ARCO), a management program currently implemented in Mexico to combat HLB.
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Wangpradit, Nuntika, Susanna Macha, Nabeelah Phooteh, Nurakmal Yusohyo, Amuna Waedoloh, and Sirikhwan Manee. "Determination of required hydrophilic-lipophilic balance of Amesiodendron chinense (Merr.) Hu oil and development of stable cream formulation." OCL 29 (2022): 29. http://dx.doi.org/10.1051/ocl/2022011.
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Amesiodendron chinense (Merr.) Hu oil is reported to use for the treatment of skin disease by Thai folk medicine. Its hydrophilic-lipophilic balance (HLB) value is very important for developing a stable cream formulation. This study aimed to determine the required hydrophilic-lipophilic balance (rHLB) value of Amesiodendron chinense (Merr.) Hu oil and to develop a stable cream formulation. Herbal cream containing Amesiodendron chinense (Merr.) Hu oil was prepared by phase inversion temperature technique using water, Tween80, and Span60. The first series of 11 emulsions with HLB values ranging from 5.0 to 15.0 and the second series of eight emulsions with a smaller interval in HLB values from 5.0 to 7.8 were prepared. rHLB of coconut oil was also determined for validation of methodology. Creaming index is the established parameter to determine rHLB and to develop stable emulsion. Emulsions with optimum emulsifier concentration resulted in less percentage-creaming index. Utilizing determined rHLB, Amesiodendron chinense (Merr.) Hu cream was formulated and evaluated for different physical parameters including viscosity, color, odor, texture, and pH. Finally, the results showed the rHLB value of coconut oil and Amesiodendron chinense (Merr.) Hu oil was 5.4 and 6.2, respectively. The stable creams were developed with a 3% emulsifier. Physical parameters were found to be consistent over 6 cycles of accelerated stability test under 4 and 45○C. Physical properties of cream evaluation ensure the stability of the developed cream. rHLB value of Amesiodendron chinense (Merr.) Hu oil was exhibited, and the stable creams were successfully formulated by utilizing determined rHLB.
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Periadnadi, Periadnadi, Diah Kharisma Sari, and Nurmiati Nurmiati. "ISOLASI DAN KEBERADAAN KHAMIR POTENSIAL PEMFERMENTASI NIRA AREN (Arenga pinnata Merr.) DARI DATARAN RENDAH DAN DATARAN TINGGI DI SUMATERA BARAT." Bioeksperimen: Jurnal Penelitian Biologi 4, no. 1 (2018): 29–36. http://dx.doi.org/10.23917/bioeksperimen.v4i1.5927.
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Penelitian bertujuan untuk mengisolasi dan mengkarakter khamir potensial pemfermentasi nira aren segar dari dataran rendah dan dataran tinggi di Sumatera Barat. Penelitian menggunakan metode eksperimen yang hasilnya disajikan secara deskriptif. Parameter yang diamati meliputi total mikroba, total khamir, uji potensi isolat khamir melalui uji fermentasi, karakter morfologi isolat khamir potensial pemfermentasi secara in vitro, serta analisis biokimiawi nira aren. Hasil penelitian menunjukkan bahwa keberadaan mikroba alami nira aren tertinggi terdapat pada sampel PAM1 (168 x 104 cfu/ml), total khamir tertinggi terdapat pada sampel HLB (85 x 104 cfu/ml), sedangkan presentase khamir tertinggi terdapat pada sampel HLB (69,1%). Uji potensi isolat melalui uji fermentasi diperoleh 5 isolat yang positifmemfermentasi alkohol. Berdasarkan karakter morfologi isolat-isolat khamir dari beberapa lokasi sampel secara in vitro didapatkan 3 isolat genus Hanseniaspora, 1 isolat genus Schizosaccharomyces, dan 1 isolat genus Saccharomyces.
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Hariyadi, Dewi Melani, Noorma Rosita, and Fitria Nugrahaeni. "Formulation, Characteristic Evaluation, Stress Test and Effectiveness Study of Matrix Metalloproteinase-1 (MMP-1) Expression of Glutathione Loaded Alginate Microspheres and Gel." Pharmaceutical Sciences 24, no. 4 (2018): 304–12. http://dx.doi.org/10.15171/ps.2018.44.
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Background: The present study aimed to formulate and evaluate the stability, characteristics and effectiveness of glutathione-loaded alginate microspheres through increased lipophilicity using surfactant with a Hydrophylic-Lipophilic Balance (HLB) value equal to 7. The selection of glutathione as an antioxidant was based on its prominent role in maintaining intracellular redox balance. Alginate was used as the polymer, while calcium chloride constituted a cross-linking agent and Tween and Span were employed as surfactants. Methods: The study applied an ionotropic gelation-aerosolization method. Microspheres were characterized by their morphology, size, drug loading, entrapment efficiency and yield. Stress testing utilized a forced degradation method, while an effectiveness study of glutathione incorporated a Matrix Metalloproteinase I (MMP-1) parameter on mouse skin. Glutathione-microspheres, to which had been added surfactants with a HLB value equal to 7, were compared to those without surfactants. Results: Microspheres demonstrated both high yield and encapsulation efficiency. From the stability study conducted, it was evident that the glutathione-microspheres with additional surfactant were more stable than glutathione with surfactant, but without microspheres. Similarly, the glutathione-microspheres with additional surfactant were more stable than the glutathione without surfactant. The in vivo effectivity showed lipophilic glutathione microspheres were able to decrease MMP-1 expression in the dermis tissue of mice. Conclusion: The results of freeze-dried glutathione-loaded alginate microspheres with surfactant with a HLB value equal to 7 can be utilized as potential glutathione delivery systems.
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Fernandes, Caio P., Manuela P. Mascarenhas, Fiorella M. Zibetti, et al. "HLB value, an important parameter for the development of essential oil phytopharmaceuticals." Revista Brasileira de Farmacognosia 23, no. 1 (2013): 108–14. http://dx.doi.org/10.1590/s0102-695x2012005000127.
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Pedroso, Mateus Silva, Terezinha Aparecida Guedes, Willian Luís de Oliveira, Werica Bruna da Silva Valim, William Mario de Carvalho Nunes, and Vanderly Janeiro. "Huanglongbing vector insect counting (HLB) by GAMLSS." Acta Scientiarum. Technology 46, no. 1 (2024): e62579. http://dx.doi.org/10.4025/actascitechnol.v46i1.62579.
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Citriculture is one of the most important agricultural activities globally, with Brazil being one of the leading world producers. Thus, such activity is essential for the country's economy and the producers who depend on it. In this sense, the fight against Huanglongbing, one of the most devastating citrus diseases caused by vector insects, is essential to guarantee the quality of the fruit and avoid economic losses. The present work analyzed the counting of insect vectors in a commercial orange orchard in an observational study carried out in the municipality of Paranavaí, state of Paraná, Brazil, using the methodologies of generalized linear mixed models (GLMM) and generalized additive models for location, scale, and form (GAMLSS), with Negative Binomial probability distribution. Data were obtained by counting insects trapped in sticky traps at twelve fixed points in the orchard at three different heights and collected over seven fortnights. The results indicated that the GAMLSS model presented better results by including the linear predictor for modeling the scale parameter associated with the study factors based on the AIC criterion and diagnostic analysis tools.
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Singh, Ashok Kumar, Lovely Kumari, Kavita Dhariyal, et al. "Design, Synthesis, Theoretical, Spectroscopic and Molecular Docking Studies of Ruthenium and Zinc Complexes and their Antimycobacterial Study." Asian Journal of Chemistry 34, no. 10 (2022): 2611–22. http://dx.doi.org/10.14233/ajchem.2022.23867.
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The six mononuclear complexes of ruthenium and zinc viz. [Ru(bpy)2(HL1)]Cl (ML1), [Ru(bpy)2(HL2)]Cl (ML2), [Ru(bpy)2(HL3)]Cl (ML3), [ZnCl(H2O)HL1]Cl (ML4), [ZnCl(H2O)HL2]Cl (ML5), [ZnCl(H2O)HL3]Cl (ML6); bpy = 2,2′-bipyridyl, HL = substituted thiosemicarbazone: HL1 = Cl, HL2 = OCH3, HL3 = OCH2Ph) were synthesized and characterized by elemental analysis, IR, 1H and 13C NMR, UV-Vis and ESI-MS spectroscopy techniques. The gas phase geometries of all the complexes have been optimized by density functional theory (DFT). The antimycobacterial activity of all the compounds was performed initially at 100 μM concentration, followed by MIC determination studies with compounds, which showed 90% reduction in fluorescence intensity. In addition, molecular docking analysis was performed to know the interactions between complexes and their probable binding sites in penicillin binding protein (PBP2). The 90% reduction in fluorescence intensity of the mycobacterial cultures were observed with HL2, HL3 and ML3. The MIC determination study showed good inhibition of ML3 and HL3 treated cultures even at 25 μM concentration. The potential activity shown by HL3 and ML3 cultures shows to be promising compounds, which may be further optimized for improved antimycobacterial activity. Electronic properties and various reactivity descriptors have been determined theoretically and an attempt has been perform to establish the correlation between biological activity and these parameters for the concerned metal complexes.
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Jovanovic, Slobodan, and Aleksandra Nastasovic. "On the formation of porous structure during the synthesis of macroporous copolymers based on glycidyl methacrylate." Chemical Industry 58, no. 11 (2004): 487–92. http://dx.doi.org/10.2298/hemind0411487j.
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The results obtained during the investigation of the influence of the inert component composition and the type of copolymerization reaction on the porosity parameters of the macroporous copolymer of glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGMA) [abbreviated poly(GMA-co-EG-DMA)] are presented. A mixture of cyclohexanol and aliphatic alcohol or non-ionic surfactants with hydrophilic-lipophilic balance values (HLB) of 5 or 9 was used as the inert component. The copolymerization was performed in suspension and in a cast. It was shown that poly(GMA-co-EGDMA) samples with enhanced porosity were obtained in the case of copolymerization in a cast, compared with samples obtained by suspension copolymerization. Also, it was concluded that the inert component solubility parameter cannot be used as the only criterium which determines the formation of the macro porous structure in poly(GMA-co-EGDMA).
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Sahota, Ravin S., and Sam M. Dakka. "Investigation the Stability of Water in Oil Biofuel Emulsions Using Sunflower Oil." ChemEngineering 4, no. 2 (2020): 36. http://dx.doi.org/10.3390/chemengineering4020036.
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Targets to reduce CO2 emissions by 75% and NOx emissions by 90% by 2050 in aviation have been set by The Advisory Council for Aviation Research and Innovation in Europe. Sustainable fuels, e.g., emulsified biofuel, have demonstrated promise in reducing emissions and greenhouse gases. The aim of this project is to investigate the stability of a water in oil emulsion using sunflower oil. The primary objective is to achieve an emulsion which is stable for at least 4 days, and the secondary objective is to investigate how altering the emulsification parameter values of the surfactant hydrophilic-lipophilic balance (HLB), energy density and sonotrode depth in an ultrasonication procedure can impact the stability. The stability of each emulsion was measured over a period of 14 days. The main outcome is that two of the 14 emulsions made remained stable for at least 14 days using a surfactant HLB of five, which proved to be the optimum value from those tested. The results also show that, by using the sonotrode in a higher starting position, emulsions achieved a greater stability. Furthermore, over-processing of the emulsion was determined, with the point of over-processing lying between an energy density of 75 and 200 W.s/mL.
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Zhang, Lei, and Guohe Que. "Influence of the HLB parameter of surfactants on the dispersion properties of brine in residue." Colloids and Surfaces A: Physicochemical and Engineering Aspects 320, no. 1-3 (2008): 111–14. http://dx.doi.org/10.1016/j.colsurfa.2008.01.035.
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Esquena, J., and C. Solans. "Influence of the HLB parameter of nonionic surfactants on normal and reversed-phase thin layer chromatography." Colloids and Surfaces A: Physicochemical and Engineering Aspects 189, no. 1-3 (2001): 85–92. http://dx.doi.org/10.1016/s0927-7757(01)00583-0.
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Salager, Jean-Louis, Raquel Antón, Johnny Bullón, Ana Forgiarini, and Ronald Marquez. "How to Use the Normalized Hydrophilic-Lipophilic Deviation (HLDN) Concept for the Formulation of Equilibrated and Emulsified Surfactant-Oil-Water Systems for Cosmetics and Pharmaceutical Products." Cosmetics 7, no. 3 (2020): 57. http://dx.doi.org/10.3390/cosmetics7030057.
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The effects of surfactant molecules involved in macro-, mini-, nano-, and microemulsions used in cosmetics and pharmaceuticals are related to their amphiphilic interactions with oil and water phases. Basic ideas on their behavior when they are put together in a system have resulted in the energy balance concept labeled the hydrophilic-lipophilic deviation (HLD) from optimum formulation. This semiempirical equation integrates in a simple linear relationship the effects of six to eight variables including surfactant head and tail, sometimes a cosurfactant, oil-phase nature, aqueous-phase salinity, temperature, and pressure. This is undoubtedly much more efficient than the hydrophilic-lipophilic balance (HLB) which has been used since 1950. The new HLD is quite important because it allows researchers to model and somehow predict the phase behavior, the interfacial tension between oil and water phases, their solubilization in single-phase microemulsion, as well as the corresponding properties for various kinds of macroemulsions. However, the HLD correlation, which has been developed and used in petroleum applications, is sometimes difficult to apply accurately in real cases involving ionic–nonionic surfactant mixtures and natural polar oils, as it is the case in cosmetics and pharmaceuticals. This review shows the confusion resulting from the multiple definitions of HLD and of the surfactant parameter, and proposes a “normalized” Hydrophilic-Lipophilic Deviation (HLDN) equation with a surfactant contribution parameter (SCP), to handle more exactly the effects of formulation variables on the phase behavior and the micro/macroemulsion properties.
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Kurnia, Rani, Dian Asfriany Nurfalah, Deana Wahyuningrum, Taufan Marhaendrajana, and Utjok W.R Siagian. "Lessons Learned in Interfacial Tension Prediction Using a Mixture of Sulfonate- and Ethoxylate-based Surfactants in a Waxy Oil-brine System." Journal of Engineering and Technological Sciences 55, no. 6 (2023): 627–38. http://dx.doi.org/10.5614/j.eng.technol.sci.2023.55.6.1.
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The chemical-enhanced oil recovery (CEOR) method is applied to change reservoir rock or fluid characteristics by injecting alkaline, surfactant, and polymer or a combination of two or three of the compounds. Surfactant flooding improves oil recovery by reducing the interfacial tension between oil and water. Selecting reservoir surfactants, especially microemulsions, requires careful screening. This study predicted waxy oil system interfacial tension using surfactant mixtures at below- and above-optimum salinity. To predict the interfacial tension, microemulsion types, HLB, ideal salinity, and HLD were used. The study predicted oil-surfactant-water interfacial tension using SAE, FEO, and their mixtures. We improved the Huh equation by adding a fitting parameter, β, to accommodate the transition from type III to type II microemulsions as salinity increases. With increasing salinity, anionic surfactant’s hydrophilic-hydrophobic interactions change, affecting the values and surfactant layer thickness. This study improved hydrophilic-lipophilic deviation (HLDN) by establishing a fixed interval for nonionic surfactants. Van der Waals attraction, values and interface surfactant layer thickness are connected, reflecting the fact that lower values reduce interfacial tension better. This study also found that surfactant packing at the oil-water interface increases the order of the oil-solution ratio and the microemulsion values with polarity.
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Tale Masoule, Mohammad Sadegh, and Ali Ghahremaninezhad. "The Relationship between Molecular Structure and Foaming of Poly(ethylene glycol)—Poly(propylene glycol) Triblock Surfactants in Cementitious Materials." Buildings 14, no. 7 (2024): 2100. http://dx.doi.org/10.3390/buildings14072100.
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This study investigates the relationship between the molecular structure and foaming of poly(ethylene glycol) and poly(propylene glycol) triblock copolymers in Portland cement pastes. Four copolymers with different molecular structures were studied at varying concentrations. All copolymers showed a reduction in surface tension of the cement pore solution; however, only some of them demonstrated foaming and air entraining in cement paste. The results indicated that the molecular structure parameter, hydrophilic-to-lipophilic balance (HLB), has a direct relationship with the foaming and air-entraining performance of the copolymers. The total organic carbon measurements showed very small adsorption of these non-ionic copolymers on hydrating cement particles due to the lack of surface charge needed to interact with the heterogeneously charged surface of hydrating cement. In addition, these copolymers did not seem to affect the flow of cement paste due to a lack of adsorption on cement particles. The cement paste modified with the copolymers showed increased water sorption compared to the control paste due to the increased capillary porosity and slight increase in pore surface hydrophilicity. However, the freeze-thaw resistance was shown to improve with an increase in the number of air voids in the modified cement pastes. The findings establish the relationship between molecular properties of copolymers and their air-entraining performance in cement paste to mitigate the damages caused by freeze-thaw action.
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Taj, Muhammad Babar, Muneera D. F. Alkahtani, Uzma Ali, et al. "New Heteroleptic 3D Metal Complexes: Synthesis, Antimicrobial and Solubilization Parameters." Molecules 25, no. 18 (2020): 4252. http://dx.doi.org/10.3390/molecules25184252.
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The microbial resistance to current antibiotics is increasing day by day, which in turn accelerating the development of new effective drugs. Several studies have proved the high antimicrobial potential of the interaction of several organic ligands with a variety of metal ions. In the present study, a conventional method has been adopted in the synthesis of twelve new heteroleptic complexes of cobalt (II), nickel (II), copper (II) and zinc (II) using three aldimines, namely, (HL1 ((E)-2-((4-chloro-2-hydroxybenzylidene)amino)-3,4-dimethyl-5-phenylcyclopent-2-en-1-one), HL2 ((Z)-3-((4-chlorobenzylidene)amino)-4-hydroxy-5-nitrobenzenesulfonic acid) HL3 (2,2′-((1,2-phenylenebis(azaneylylidene))bis(methaneylylidene))diphenol)) as primary ligands, while phenyl glycine was the secondary ligand. The synthesized compounds were characterized by UV-vis, IR and multinuclear (1H and 13C) NMR spectroscopy, elemental analysis, and electrical conductance. The IR study revealed the coordination of the aldimine derivatives with the -OH and N atom of imine moiety. In contrary to this, the phenyl glycine coordinated to the metal ions via oxygen of carboxylate and nitrogen of the amino group. The spectroscopic analysis unveiled the tetrahedral geometry of the synthesized metal (II) complexes, except for ligand HL3 which exhibited octahedral geometry. The synthesized compounds generally showed antibacterial activity for all microbes, except Ni (II) complexes lacking sensitivity. Furthermore, to access the bioavailability, the synthesized complexes were screened for their solubilization in the micellar media of sodium lauryl sulphate. The metal complex–surfactant interaction was revealed by UV-vis spectroscopy and electrical conductivity measurements.
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ZGODA, MARIAN, WIESLA WHRECZUCH, MARCIN WOSKOWICZ, MICHAL NACHAJSKI, and MICHAL KOLODZIEJCZYK. "Surfactants from the group of fatty acids polyoxyethylenated esters. Part I. Hydrophylic-lipophilic equilibrium (HLB), solubility parameter and a type of surface activity of the rape oil fatty acids methyl esters oxyethylenation products." Polimery 48, no. 05 (2003): 365–70. http://dx.doi.org/10.14314/polimery.2003.365.
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Yu, Qibin, Fanwei Dai, Riccardo Russo, et al. "Phenotypic and Genetic Variation in Morphophysiological Traits in Huanglongbing-Affected Mandarin Hybrid Populations." Plants 12, no. 1 (2022): 42. http://dx.doi.org/10.3390/plants12010042.
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Huanglongbing (HLB) caused by ‘Candidatus Liberibacter asiaticus’ (CLas) is the most costly disease for the global citrus industry. Currently, no effective tools have been found to control HLB. Most commercial citrus varieties are susceptible to HLB, though some citrus hybrid cultivars have reduced sensitivity to the disease. Citrus breeding populations contain a large diversity of germplasm, with thousands of unique genotypes exhibiting a broad range of phenotypes. Understanding phenotypic variation and genetic inheritance in HLB-affected mandarin hybrid populations are crucial for breeding tolerant citrus varieties. In this study, we assessed 448 diverse mandarin hybrids coming from 30 crosses, and 45 additional accessions. For HLB tolerance, we measured HLB severity visual score and CLas titers by qPCR. We also measured seven morphophysiological traits indirectly related to HLB tolerance with leaf area index (LAI), leaf area (LA), leaf mass per area (LMA), photosystem II parameters (Fv/Fo, Fv/Fm), and photochemical performance index (PIabs). By estimating the genetic variation in five half-sib families, we estimated the heritability of phenotypic traits and found a significant genetic effect on HLB visual score and photosynthesis parameters, which indicates opportunities for the genetic improvement of HLB tolerance. In addition, although it is easy to identify infected trees based on HLB symptomatic leaves, visually phenotyping whole trees can be difficult and inconsistent due to the interpersonal subjectivity of characterization. We investigated their relationships and found that LAI was highly correlated with HLB score, with correlation coefficients of r = 0.70 and r = 0.77 for the whole population and five half-sib families, respectively. Photochemical parameters showed significant correlation with HLB severity and responded differentially with the side of the canopy. Our study suggests that LAI and photochemical parameters could be used as a rapid and cost-effective method to evaluate HLB tolerance and inheritance in citrus breeding programs.
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Khuimphukhieo, Ittipon, Jose Carlos Chavez, Chuanyu Yang, et al. "Assessing Huanglongbing Severity and Canopy Parameters of the Huanglongbing-Affected Citrus in Texas Using Unmanned Aerial System-Based Remote Sensing and Machine Learning." Sensors 24, no. 23 (2024): 7646. https://doi.org/10.3390/s24237646.
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Huanglongbing (HLB), also known as citrus greening disease, is a devastating disease of citrus. However, there is no known cure so far. Recently, under Section 24(c) of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), a special local need label was approved that allows the trunk injection of antimicrobials such as oxytetracycline (OTC) for HLB management in Florida. The objectives of this study were to use UAS-based remote sensing to assess the effectiveness of OTC on the HLB-affected citrus trees in Texas and to differentiate the levels of HLB severity and canopy health. We also leveraged UAS-based features, along with machine learning, for HLB severity classification. The results show that UAS-based vegetation indices (VIs) were not sufficiently able to differentiate the effects of OTC treatments of HLB-affected citrus in Texas. Yet, several UAS-based features were able to determine the severity levels of HLB and canopy parameters. Among several UAS-based features, the red-edge chlorophyll index (CI) was outstanding in distinguishing HLB severity levels and canopy color, while canopy cover (CC) was the best indicator in recognizing the different levels of canopy density. For HLB severity classification, a fusion of VIs and textural features (TFs) showed the highest accuracy for all models. Furthermore, random forest and eXtreme gradient boosting were promising algorithms in classifying the levels of HLB severity. Our results highlight the potential of using UAS-based features in assessing the severity of HLB-affected citrus.
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Haque, Anzarul, Muzaffar Iqbal, Mariam K. Alamoudi, and Prawez Alam. "A Selective and Accurate LC-MS/MS Method for Simultaneous Quantification of Valsartan and Hydrochlorothiazide in Human Plasma." Separations 10, no. 2 (2023): 119. http://dx.doi.org/10.3390/separations10020119.
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The fixed dose combination of valsartan (VAL) and hydrochlorothiazide (HCTZ) is the most commonly prescribed medicine for the effective treatment of hypertension. In this study, a simple sensitive and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous quantitation of VAL and HCTZ in human plasma by using irbesartan (IRB) and hydroflumethiazide (HFMZ) as their specific internal standards (ISs). HLB cartridge-based solid-phase extraction was used for the extraction of analytes and ISs. The chromatographic separation was achieved on Lichrocart RP Select (125 × 4 mm), 5 nm with the mobile phase composition of acetonitrile: 10 mM ammonium acetate buffer: 95:05, v/v, at flow rate of 0.5 mL/min. The turbo ion electrospray ionization in negative mode was used as ion source for the sample ionization. The precursor to product ion transitions were 434.10 > 179.10 (VAL), 295.70 > 204.90 (HCTZ), 427.10 > 192.90 (IRB), and 329.90 > 302.40 (HFMZ) for detection and quantification of analytes and their ISs. The retention times of VAL and HCTZ were 1.90 min and 2.30 min, respectively. The range for the calibration curves of VAL and HCTZ were 50.2–6018.6 ng/mL and 1.25–507.63 ng/mL, respectively, with good linearity having correlation coefficient values of ≥0.995 for both VAL and HCTZ. All validation parameter results (selectivity, precision and accuracy, matrix effects and stabilities) were within the acceptable range as per USFDA guideline for bioanalytical method validation. The intra-day and inter-day accuracy data for VAL were within the range of 105.68–114.22% and 98.41–108.16%, respectively, whereas for HCTZ they were 87.01–101.18% and 95.16–99.37%, respectively. The ion suppression effects produced for VAL and ion enhancement effects produced for HCTZ were insignificant according to the proposed sample cleanup procedure. The developed LC-MS/MS method was successfully applied to bioequivalence study on healthy volunteers.
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Sharma, Prerana. "Stimulated Raman scattering of ultra intense hollow Gaussian beam in relativistic plasma." Laser and Particle Beams 33, no. 3 (2015): 489–98. http://dx.doi.org/10.1017/s0263034615000488.
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AbstractEffect of relativistic nonlinearity on stimulated Raman scattering (SRS) of laser beam propagating carrying null intensity in center [hollow Gaussian beam (HGB)] is studied in collisionless plasma. The construction of the equations is done employing the fluid theory which is developed with partial differential equation and Maxwell's equations. The phenomenon of SRS is shown along with the excitation of seed plasma wave considering relativistic nonlinearity. The power of plasma wave is observed for higher order of HGB. The Raman back reflectivity is studied numerically for various orders of hollow Gaussian laser beam (HGLB) and the numerical analysis shows that these parameters play vital role on reflectivity characteristics. It is observed that the Raman back reflectivity is less for the higher order of HGLB.
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Osipova, S. V., A. V. Rudikovskii, A. V. Permyakov, et al. "Physiological responses to water deficiency in bread wheat (Triticum aestivum L.) lines with genetically different leaf pubescence." Vavilov Journal of Genetics and Breeding 24, no. 8 (2020): 813–20. http://dx.doi.org/10.18699/vj20.678.
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Studying the relationship between leaf pubescence and drought resistance is important for assessing Triticum aestivum L. genetic resources. The aim of the work was to assess resistance of common wheat genotypes with different composition and allelic state of genes that determine the leaf pubescence phenotype. We compared the drought resistance wheat variety Saratovskaya 29 (S29) with densely pubescent leaves, carrying the dominant alleles of the Hl1 and Hl3 genes, and two near isogenic lines, i: S29 hl1, hl3 and i: S29 Hl2aesp, with the introgression of the additional pubescence gene from diploid species Aegilops speltoides. Under controlled conditions of the climatic chamber, the photosynthetic pigments content, the activity of ascorbate-glutathione cycle enzymes and also the parameters of chlorophyll fluorescence used to assess the physiological state of the plants photosynthetic apparatus were studied in the leaves of S29 and the lines. Tolerance was evaluated using the comprehensive index D, calculated on the basis of the studied physiological characteristics. The recessive state of pubescence genes, as well as the introduction of the additional Hl2aesp gene, led to a 6-fold decrease in D. Under the water deficit influence, the fluorescence parameters profile changed in the lines, and the viability index decreased compared with S29. Under drought, the activity of ascorbate peroxidase, glutathione reductase and dehydroascorbate reductase in the line i: S29 hl1, hl3 decreased 1.9, 3.3 and 2.3 times, in the line i: S29 Hl2aesp it decreased 1.8, 3.6 and 1.8 times respectively, compared with S29. In a hydroponic greenhouse, line productivity was studied. Compared with S29, the thousand grains mass in the line i: S29 hl1, hl3 under water deficit was reduced. The productivity of the line i: S29 Hl2aesp was significantly reduced regardless of water supply conditions in comparison with S29. Presumably, the revealed effects are associated with violations of cross-regulatory interactions between the proteins of the trichome formation network and transcription factors that regulate plant growth and stress response.
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Shahzad, Faisal, Davie M. Kadyampakeni, and Tripti Vashisth. "Effect of Growing Media pH on Performance of Huanglongbing-Affected Young Citrus Trees." Agronomy 11, no. 3 (2021): 439. http://dx.doi.org/10.3390/agronomy11030439.
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Since the advent of Huanglongbing (HLB) disease, Florida’s citrus production has dropped by 70%. HLB-affected trees decline rapidly under high pH growing conditions. Limited nutrient availability at high soil pH has been speculated to be the cause of such rapid decline in HLB-affected trees; however, such decline is not observed in healthy citrus trees. Therefore, the objective of this study was to understand the nutrient uptake, physiological, and molecular responses of healthy (HLY) and HLB-affected (HLB) sweet orange (Citrus sinensis (L.) Osbeck) trees when grown in media maintained at different pH levels 6.0, 7.0, or 8.0. Overall, the performance of HLY and HLB trees decreased with the increase in pH conditions. HLB trees showed a significant inverse correlation between growth parameters (leaf number, shoot growth, SPAD value, stem water potential) and growing media pH whereas no such correlation was observed for HLY trees. Interesting, superior performance of HLB trees at pH 6.0 coincided with higher accumulation of Fe, Mn, and N in whole plant body as compared to high pH treatments. In contrast, HLY tree performance was significantly better at pH 7.0 compared to other pH conditions. At pH 7.0, stress related genes were upregulated in HLB leaves as compared to HLY leaves, indicating the stress response in terms of leaf abscission, reduced growth, and natural aging process was exacerbated in HLB trees at higher pH treatments. Altogether, all the physiological and molecular observations supports an interaction between HLB trees and pH, where HLB trees at pH 6.0 perform better than at higher pH.
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Sagaram, Madhulika, and Jacqueline K. Burns. "Leaf Chlorophyll Fluorescence Parameters and Huanglongbing." Journal of the American Society for Horticultural Science 134, no. 2 (2009): 194–201. http://dx.doi.org/10.21273/jashs.134.2.194.
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Chlorophyll fluorescence and photochemical and nonphotochemical quenching parameters were measured in 20 genotypes of Citrus spp. or relatives grown in the greenhouse and commercial ‘Valencia’ sweet orange (Citrus sinensis) trees at two Florida locations. The purpose was to determine the utility of measurements for early huanglongbing [HLB (Candidatus Liberibacter asiaticus)] detection in asymptomatic trees and to examine the leaf response to HLB infection. Polymerase chain reaction (PCR)-negative healthy and PCR-positive symptomatic, asymptomatic, and distant asymptomatic leaves were used for fluorescence analysis using a portable chlorophyll fluorometer. Greenhouse-grown genotypes were separated into mild, moderate, and severe symptom groups based on leaf mottling, color, and size. In general, mild symptom genotypes were characterized by increased photosystem II (PSII) excitation pressure and unregulated heat dissipation and decreased regulated heat dissipation, whereas moderate and severe symptom genotypes increased loss of photosynthetic efficiency and increased unregulated and regulated heat dissipation. Distant asymptomatic leaves could be distinguished from healthy ones in moderate and severe symptom genotypes by increased total and regulated heat dissipation measurements. In the field, overall photosynthetic efficiency and total regulated heat dissipation measurements could distinguish between healthy and asymptomatic ‘Valencia’ sweet orange leaves at the location with slow or more recent infection, but not at the location where infection appeared to progress faster or was of longer duration. Starch content followed a similar pattern. The results indicate that no single measurement uniquely described the relationship between HLB and the host in asymptomatic and healthy leaves, but accuracy of field-based detection could be strengthened by a combination of total nonphotochemical quenching, overall photosynthetic efficiency, starch content, and PCR analyses. Chlorophyll fluorescence and quenching measurements suggest a PSII-based explanation for, and temperature dependency of, leaf symptom development.
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Zapolski, Remigiusz, та Witold Musiał. "The Response Surface Methodology for Assessment of HLB Values of Mixtures of Non-Ionic Surfactants Using Parameters from Their π-A Isotherms". Molecules 29, № 10 (2024): 2351. http://dx.doi.org/10.3390/molecules29102351.
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The aim of the work was to determine important parameters of the course of π-A isotherms, which can determine the HLB (hydrophilic-lipophilic balance) value of surfactant mixtures with selected structural features, such as a straight or branched hydrocarbon chain and a double bond, using RSM (response surface methodology) computational methods. Mixtures of surfactants derived from fatty acids and sorbitan with specific HLB values were evaluated by Langmuir trough. The resulting elasticity modules (ELM) and molecules surfaces (SAM) were evaluated via response surface methodology and respective equations were calculated. The π-A isotherm determined in a Langmuir trough and the ELM and SAM parameters determined on the basis of this isotherm may be useful for determining the HLB of a fixed surfactant mixture. The RSM method used, in which ELM and SAM were assumed as two independent variables, can be a useful technique for tracking the influence of individual molecular characteristics on the hydrophilic-lipophilic properties of mixtures of surfactant compounds. Changes in HLB as a dependent variable can be described as a function of ELM and SAM.
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Phuyal, Dinesh, Thiago Assis Rodrigues Nogueira, Arun D. Jani, Davie M. Kadyampakeni, Kelly T. Morgan, and Rhuanito Soranz Ferrarezi. "‘Ray Ruby’ Grapefruit Affected by Huanglongbing II. Planting Density, Soil, and Foliar Nutrient Management." HortScience 55, no. 9 (2020): 1420–32. http://dx.doi.org/10.21273/hortsci15255-20.
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Since the arrival of Huanglongbing (HLB) disease in Florida, several management approaches, including modification of orchard architecture design and nutritional therapy, have been explored. High-density plantings anticipate early economic returns from HLB-affected orchards. With no cure available for HLB, balanced nutrient application through soil and foliar spraying can mitigate the disease. A 2-year study was conducted to investigate the effects of three grapefruit (Citrus paradisi) planting densities [single-row (300 and 440 trees per ha), and double-row high-density (975 trees per ha)], two controlled-release fertilizer (CRF) blends, and foliar-applied micronutrients (FAM) (a blend of B, Mn, and Zn at 0, 1.5, 3, and 6 times the recommended rates) on grapefruit growth and fruit yield, physiological parameters, and foliar nutrient concentrations in an HLB-affected orchard. All the trees tested positive for HLB based on real-time quantitative polymerase chain reaction (qPCR) test. The highest planting density resulted in the lowest trunk diameter and canopy volume. Despite lower yield per tree in 2019–20, 975 trees per ha planting induced the greatest fruit and solid yields per ha. Also, the fruit produced from 975 trees per ha planting tended to be acidic with the deposition of more soluble solids. Use of CRF with higher micronutrients increased canopy volume with the expense of reduced fruit number in 2019–20. FAM did not affect cycle threshold (Ct) value and tree growth parameters. Fruit yield, photosynthesis rate, and stomatal conductance (gS) decreased, and all leaf nutrient concentrations except B increased in 2019–20 with all FAM rates tested. In conclusion, our study showed that high-density planting optimizes yield under HLB-endemic conditions. In addition, supplemental soil and foliar micronutrient application do not enhance yield of HLB-affected trees over a 2-year timeframe, warranting further research for confirmation of results.
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Islam, Md Rashidul, Md Nazmul Islam, Md Zahangir Alam, Md Mosharraf Hossain, Md Al Mobasher Hussen, and Mohammad Monirul Hasan Tipu. "Chemical inducers, nutrient management, guava intercropping and insecticides can reduce huanglongbing incidence and severity in Sweet orange." Archives of Agriculture and Environmental Science 5, no. 4 (2020): 436–46. http://dx.doi.org/10.26832/24566632.2020.050401.
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Huanglongbing (HLB) or citrus greening is the most economically devastating disease of citrus in the world. HLB is a vector-borne disease and transmitted by Asian Citrus psyllid (ACP). HLB is now a serious threat to the cultivation and expansion of Sweet orange and Mandarin in Bangladesh. As no suitable cure is available against the disease, inducing plant immunity by chemical inducers or nutrient management and intercropping could be an effective way to combat this challenge. In this study, two inducers viz., Bion (Acibenzolar S-methyl) and Bactroban (Bismerthizol), nutrients formulations SICOGREEN® (soil application) and foliar spray, intercropping with guava, spraying guava leaf extract (10%), foliar spray with insect growth regulators (IGR) such as Heron (Lufenuron), insecticides such as Neonicotinoids/Imidachloropid + Thiomethoxam and foliar spray of Beauveria bassiana (Commercial formulation) showed comparatively better performance as compared to untreated control considering both HLB incidence and severity in both locations (Haluaghat and Bhaluka) of Sweet orange orchards. All these treatments reduced HLB incidence by 57.5 to 89.44% and HLB severity by 54.16 to 80.35% in Sweet orange considering both Haluaghat and Bhaluka orchards. The results revealed that Bion (Acibenzolar S-methyl), nutrients formulations SICOGREEN® (soil and foliar application), intercropping with guava, spraying guava leaf extract, foliar spray of insecticides can be integrated to reduce HLB incidence and severity in Sweet orange. Some of these treatments have also some positive effects on plant growth and yield parameters of Sweet orange as compared to control. These results comprehensively suggest that chemical inducers and nutrient management seem a better alternative to control HLB aimed to increase tree lifespan and productivity.
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Bhandari, Deepak, and Anant P. Regmi. "Influence of Long-term Use of Organic and Inorganic Nutrients on HLB Disease of Wheat under Rice-Wheat Cropping Pattern." Nepal Agriculture Research Journal 9 (November 30, 2014): 76–84. http://dx.doi.org/10.3126/narj.v9i0.11644.
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Helminthosporium leaf blight (HLB) is one of the most destructive diseases of wheat in terai (plain) region of Nepal. This study was conducted to determine the effect of long-term application of various levels of nitrogen (N), phosphorus (P), potassium (K) and organic nutrients on HLB disease of wheat. The experiment was superimposed on long-term fertility experiment conducted in RCB design with three replications under rice-wheat cropping pattern at National wheat research program (NWRP), Bhairahawa, Nepal. The treatments include various combinations of nitrogen 100 kg ha-1, phosphorus 0 and 60 kg ha-1, and potash 0, 50 and 100 kg ha-1 with or without Sesbania (Sesbania cannabina) and farm yard manure (FYM). Area under disease progress curve (AUDPC) was calculated using the disease scores and yield parameters were recorded. Among the inorganic nutrients, long-term deficiency of potash in the field markedly enhances the HLB disease. Application of phosphorus in various doses increased the HLB severity in absence of potash. Regular application of at least potash 50 kg ha- 1 in wheat noticeably reduced the HLB disease. Regular use of FYM 10 ton ha-1 for long-term considerably reduced the HLB disease but long-term use of Sesbania as green manure did not show any impact on HLB severity. Inclusion of potash in nutrients considerably increased the yield and thousand grain weight (TGW) of wheat. In long term, balanced use of inorganic and organic nutrients with special attention on regular inclusion of potash and FYM in the nutrient combinations is vital in suppression of HLB disease under rice-wheat cropping pattern.Nepal Agric. Res. J. Vol. 9, 2009, pp. 76-84DOI: http://dx.doi.org/10.3126/narj.v9i0.11644
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Huang, Huasheng, Jizhong Deng, Yubin Lan, et al. "Detection of Helminthosporium Leaf Blotch Disease Based on UAV Imagery." Applied Sciences 9, no. 3 (2019): 558. http://dx.doi.org/10.3390/app9030558.
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Helminthosporium leaf blotch (HLB) is a serious disease of wheat causing yield reduction globally. Usually, HLB disease is controlled by uniform chemical spraying, which is adopted by most farmers. However, increased use of chemical controls have caused agronomic and environmental problems. To solve these problems, an accurate spraying system must be applied. In this case, the disease detection over the whole field can provide decision support information for the spraying machines. The objective of this paper is to evaluate the potential of unmanned aerial vehicle (UAV) remote sensing for HLB detection. In this work, the UAV imagery acquisition and ground investigation were conducted in Central China on April 22th, 2017. Four disease categories (normal, light, medium, and heavy) were established based on different severity degrees. A convolutional neural network (CNN) was proposed for HLB disease classification. The experiments on data preprocessing, classification, and hyper-parameters tuning were conducted. The overall accuracy and standard error of the CNN method was 91.43% and 0.83%, which outperformed other methods in terms of accuracy and stabilization. Especially for the detection of the diseased samples, the CNN method significantly outperformed others. Experimental results showed that the HLB infected areas and healthy areas can be precisely discriminated based on UAV remote sensing data, indicating that UAV remote sensing can be proposed as an efficient tool for HLB disease detection.
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Šilha, Josef, Milan Bareš, Ivo Zeman, and Jan Šmidrkal. "The HLB number determination of polyoxyethylene surfactants." Collection of Czechoslovak Chemical Communications 54, no. 4 (1989): 945–52. http://dx.doi.org/10.1135/cccc19890945.
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The Hydrophile-Lipophile-Balance (HLB) numbers were evaluated on the basis of three different, commonly used methods of determination and calculation, in a series of lauric, resp. stearic acids and lauryl alcohol oxyethylenation products prepared by an alkali-catalyzed reaction in a similar scale of hydrophobe: ethylene oxide molar ratios. The results showed that, due to the different principles of the used methods, the HLB numbers were obtained with a great variance, limiting their use as parameters for estimation of the application effectiveness of non-ionic surfactants of the polyoxyethylene type. The HLB concept was not found able to consider the complicated composition of the studied types of surfactants and to provide relevant information in the already mentioned sense.
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Abdelouahab, Mohammed-Salah, René Lozi, and Guanrong Chen. "Complex Canard Explosion in a Fractional-Order FitzHugh–Nagumo Model." International Journal of Bifurcation and Chaos 29, no. 08 (2019): 1950111. http://dx.doi.org/10.1142/s0218127419501116.
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This article investigates the complex phenomena of canard explosion with mixed-mode oscillations, observed from a fractional-order FitzHugh–Nagumo (FFHN) model. To rigorously analyze the dynamics of the FFHN model, a new mathematical notion, referred to as Hopf-like bifurcation (HLB), is introduced. HLB provides a precise definition for the change between a fixed point and an [Formula: see text]-asymptotically [Formula: see text]-periodic solution of the fractional-order dynamical system, as well as the stability of the FFHN model and the appearance of the HLB. The existence of canard oscillations in the neighborhoods of such HLB points are numerically investigated. Using a new algorithm, referred to as the global-local canard explosion search algorithm, the appearance of various patterns of solutions is revealed, with an increasing number of small-amplitude oscillations when two key parameters of the FFHN model are varied. The numbers of such oscillations versus the two parameters, respectively, are perfectly fitted using exponential functions. Finally, it is conjectured that chaos could occur in a two-dimensional fractional-order autonomous dynamical system, with the fractional order close to one. After all, the article demonstrates that the FFHN model is a very simple two-dimensional model with an incredible ability to present the complex dynamics of neurons.
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Tirado-Corbalá, Rebecca, Elvin Román-Paoli, Alejandro E. Segarra-Carmona, Consuelo Estévez de Jensen, and Dania Rivera-Ocasio. "Early Response of ‘Mexican’ Lime, ‘Fina’ Clementine Mandarin, and ‘Campbell’ Valencia Orange on Selected Rootstocks Grown under Fertigation Practices in an Oxisol in Puerto Rico." Horticulturae 8, no. 6 (2022): 513. http://dx.doi.org/10.3390/horticulturae8060513.
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In Puerto Rico, Huanglongbing (HLB), detected in 2009, continues to produce losses in orchards across the island. Efforts to produce clean propagation materials and select different combinations of scions and rootstocks to mitigate the disease have been a priority. In 2016, an experiment was established in Isabela in Coto clay series soils at 120 m to assess ‘Mexican’ lime, ‘Fina’ clementine mandarin, and ‘Campbell’ Valencia orange grafted in ‘Swingle’ citrumelo, ‘HRS 812’, and ‘HRS 897’. Tree growth parameters, tree fruit production, HLB incidences, and tree mortality were evaluated under a fertigation system. Higher fruit production was obtained with ‘Fina’ clementine mandarin and ‘Campbell’ Valencia orange when grafted in ‘HRS 812’ followed by ‘HRS 897’. ‘Mexican’ lime had higher fruit production when grafted in ‘HRS 897’. On the basis of total fruit production and HLB incidence, ‘HRS 812’ was outstanding, yielding fruits with higher values even though they were infected with HLB. Moreover, ‘HRS 897’ rootstock was demonstrated to be a potential rootstock for the Puerto Rico conditions.
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Yang, Chao-Feng, Zhi-Hong Yin, Wen-Bin Shangguan, and Xiao-Cheng Duan. "A Study on the Dynamic Performance for Hydraulically Damped Rubber Bushings with Multiple Inertia Tracks and Orifices: Parameter Identification and Modeling." Shock and Vibration 2016 (2016): 1–16. http://dx.doi.org/10.1155/2016/3695950.
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Hydraulically damped rubber bushings (HDBs) are important for vehicle noise, vibration, and harshness (NVH) performance as they are able to decay the vehicle’s oscillation induced by engine and road. The dynamic stiffness and loss angle of an HDB are crucial and it is significant to investigate the relations between the design parameters with the dynamic stiffness and loss angle. Therefore, the force-deflection relation of the HDB is measured statically and the dynamic stiffness and loss angle are measured dynamically and the test data are analyzed with a view to examine how the measurement results are influenced by the design parameters (the number of the fluid tracks). Compared with the results predicted by a nonlinear lumped parameter model whose parameters are extracted by a parameter identification technique, using the model, the effect of the main rubber and the fluid track on the dynamic stiffness and the loss angle is investigated. A unified analytical model of HDB is also developed with the purpose of predicting the static and dynamic characteristics, and the predictions are shown to be well correlated with the measurement data. The good correlation suggests the validity of the model and the parameter identification implementation.
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Levy, Amit, Taylor Livingston, Chunxia Wang, Diann Achor, and Tripti Vashisth. "Canopy Density, but Not Bacterial Titers, Predicts Fruit Yield in Huanglongbing-Affected Sweet Orange Trees." Plants 12, no. 2 (2023): 290. http://dx.doi.org/10.3390/plants12020290.
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In Florida, almost all citrus trees are affected with Huanglongbing (HLB), caused by Candidatus Liberibacter asiaticus (CLas). We characterized various parameters of HLB-affected sweet orange trees in response to yield-improving nutritional treatment, including canopy volume, canopy density and CLas Ct values, and found that the treatment improved yield and maintained canopy density for over three years, whereas untreated HLB-affected trees declined in canopy density. The nutritional treatment did not affect CLas titer or the tree canopy volume suggesting that canopy density is a better indicator of fruit yield. To further validate the importance of canopy density, we evaluated three independent orchards (different in tree age or variety) to identify the specific traits that are correlated with fruit yields. We found that canopy density and fruit detachment force (FDF), were positively correlated with fruit yields in independent trials. Canopy density accurately distinguished between mild and severe trees in three field trials. High and low producing HLB trees had the same Ct values. Ct values did not always agree with CLas number in the phloem, as visualized by transmission electron microscopy. Our work identifies canopy density as an efficient trait to predict yields of HLB-affected trees and suggests canopy health is more relevant for yields than the CLas population.
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Pramudono, B., and H. B. Mat. "Demulsifier Selection Based On The Evaluation Of Demulsification Performance Indicators." REAKTOR 9, no. 2 (2017): 58. http://dx.doi.org/10.14710/reaktor.9.2.58-66.
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A method for characterizing and selecting demulsifiers has been developed. The development was based on either the relationships between the demulsification parameters and demulsifier performance or demulsifier characteristics and demulsifier performance. The importance of each of these parameters to performance was discussed. The result was eight demulsification performance indicators consisting of the percentage of water separation, percentage of oil separation, demulsification efficiency, demulsification effectiveness, partition coefficient, interfacial pressure, interfacial activity, and Hydrophilic Balance (HLB). Quantification of the indicators conducted by determination of the performance indexes for each indicator. It was obtained from the condition that the demulsifier exhibits good performance. Additionally, the study found a correlation between the parameters it self. The demulsifier effectiveness as well as the interfacial pressure reaches a maximum value when the partition coefficient closed unity. Increasing of the interfacial pressure, in consequence, will increase both the demulsifier effectiveness and interfacial activity. The effect of both the HLB and molecular weight on the percentage of separation indicates a weak correlation.Keywords :A method for characterizing and selecting demulsifiers has been developed. The development was based on either the relationships between the demulsification parameters and demulsifier performance or demulsifier characteristics and demulsifier performance. The importance of each of these parameters to performance was discussed. The result was eight demulsification performance indicators consisting of the percentage of water separation, percentage of oil separation, demulsification efficiency, demulsification effectiveness, partition coefficient, interfacial pressure, interfacial activity, and Hydrophilic Balance (HLB). Quantification of the indicators conducted by determination of the performance indexes for each indicator. It was obtained from the condition that the demulsifier exhibits good performance. Additionally, the study found a correlation between the parameters it self. The demulsifier effectiveness as well as the interfacial pressure reaches a maximum value when the partition coefficient closed unity. Increasing of the interfacial pressure, in consequence, will increase both the demulsifier effectiveness and interfacial activity. The effect of both the HLB and molecular weight on the percentage of separation indicates a weak correlation.Keywords : Chemical demulsifier, demulsifier performance, demulsification parameters, performance index
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Cass, J. F., and S. J. Hogan. "Two dimensionless parameters and a mechanical analogue for the HKB model of motor coordination." Biological Cybernetics 115, no. 4 (2021): 343–64. http://dx.doi.org/10.1007/s00422-021-00879-5.
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AbstractThe widely cited Haken–Kelso–Bunz (HKB) model of motor coordination is used in an enormous range of applications. In this paper, we show analytically that the weakly damped, weakly coupled HKB model of two oscillators depends on only two dimensionless parameters; the ratio of the linear damping coefficient and the linear coupling coefficient and the ratio of the combined nonlinear damping coefficients and the combined nonlinear coupling coefficients. We illustrate our results with a mechanical analogue. We use our analytic results to predict behaviours in arbitrary parameter regimes and show how this led us to explain and extend recent numerical continuation results of the full HKB model. The key finding is that the HKB model contains a significant amount of behaviour in biologically relevant parameter regimes not yet observed in experiments or numerical simulations. This observation has implications for the development of virtual partner interaction and the human dynamic clamp, and potentially for the HKB model itself.
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Deng, Xiaoling, Zihao Zhu, Jiacheng Yang, et al. "Detection of Citrus Huanglongbing Based on Multi-Input Neural Network Model of UAV Hyperspectral Remote Sensing." Remote Sensing 12, no. 17 (2020): 2678. http://dx.doi.org/10.3390/rs12172678.
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Citrus is an important cash crop in the world, and huanglongbing (HLB) is a destructive disease in the citrus industry. To efficiently detect the degree of HLB stress on large-scale orchard citrus trees, an UAV (Uncrewed Aerial Vehicle) hyperspectral remote sensing tool is used for HLB rapid detection. A Cubert S185 (Airborne Hyperspectral camera) was mounted on the UAV of DJI Matrice 600 Pro to capture the hyperspectral remote sensing images; and a ASD Handheld2 (spectrometer) was used to verify the effectiveness of the remote sensing data. Correlation-proven UAV hyperspectral remote sensing data were used, and canopy spectral samples based on single pixels were extracted for processing and analysis. The feature bands extracted by the genetic algorithm (GA) of the improved selection operator were 468 nm, 504 nm, 512 nm, 516 nm, 528 nm, 536 nm, 632 nm, 680 nm, 688 nm, and 852 nm for the HLB detection. The proposed HLB detection methods (based on the multi-feature fusion of vegetation index) and canopy spectral feature parameters constructed (based on the feature band in stacked autoencoder (SAE) neural network) have a classification accuracy of 99.33% and a loss of 0.0783 for the training set, and a classification accuracy of 99.72% and a loss of 0.0585 for the validation set. This performance is higher than that based on the full-band AutoEncoder neural network. The field-testing results show that the model could effectively detect the HLB plants and output the distribution of the disease in the canopy, thus judging the plant disease level in a large area efficiently.
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Adeleke, A. A., and F. A. Oladimeji. "Effect of Hydrophile-Lipophile Balance (HLB) of Mixed Surfactants on In-Vitro Release Profile of Ibuprofen from Semi-Synthetic Suppository Bases." Nigerian Journal of Pharmaceutical Research 17, no. 1 (2021): 109–17. http://dx.doi.org/10.4314/njpr.v17i1.12.
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Background: The emphasis on the use of surfactants in enhancing drug release from fatty suppository bases has always been on the concentration and type of surfactants. However, the Hydrophile-Lipophile Balance (HLB) of the surfactants added can be of significant effect.Objective: The study aimed at evaluating the effect of HLB of the incorporated mixed surfactants on the physical and release properties of Ibuprofen suppositories formulated with semi-synthetic fatty bases.Methodology: The preparations were carried out using 1 g mould. Ibuprofen suppositories, each containing 200 mg of Ibuprofen with semi-synthetic fatty bases (Witepsol® H15, Suppocire® CM), were prepared by fusion method. Mixed surfactants (Span® 80 and Tween® 80) were added at 4 %w/w in varied ratios to give HLB values of 4.3 to 15.0. The physical properties and release profile of the suppositories were evaluated using established procedures.Results: The physical properties of the suppositories met the standard specified in the BP. Addition of mixed surfactants greatly influenced the release of the Ibuprofen from the formulations with optimum release at lipophilic HLB (4.3) and hydrophilic HLB (12.0) for formulations in Suppocire® CM and Witepsol® H15, respectively. The release parameters majorly fitted into Higuchi’s model. The release mechanism was non-Fickian and Fickian for formulations in Suppocire® CM and Witepsol® H15, respectively.Conclusion: The variations observed in the release profiles of Ibuprofen from the suppository bases indicate that HLB value of mixed surfactants can be employed in modifying drug release from semi-synthetic fatty bases
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Hamido, Said A., Kelly T. Morgan, and Davie M. Kadyampakeni. "The Effect of Huanglongbing on Young Citrus Tree Water Use." HortTechnology 27, no. 5 (2017): 659–65. http://dx.doi.org/10.21273/horttech03830-17.
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Understanding the role of Huanglongbing (HLB) caused by Candidatus Liberibacter asiaticus on citrus (Citrus sp.) water use is critical for determining if changes in water management of commercial citrus orchards affected by this disease is necessary. Reference evapotranspiration (ETo) is the most used methodology for irrigation scheduling, particularly in light of reports that indicate the lack of water for irrigation will become a major problem in many places around the world including Florida. The objectives of this study were to determine citrus tree water relationship [water use, sap flow, and stem water potential (Ψ)] as affected by ETo and HLB. The study was initiated on Jan. 2014 on two sweet orange (Citrus sinensis) cultivars included Hamlin and Valencia grown in a fine sandy soil texture (sandy, siliceous, and hyberthermic Arenic Alaquods) in a greenhouse. Twelve weighing lysimeters of each cultivar (six HLB-affected and six nonaffected trees) were used to determine selected water relation parameters. Results indicated a significant reduction in water use, Ψ, and sap flow for affected trees when compared with nonaffected trees. Citrus water use of healthy trees during the 2-year study was 31% and 27% greater than HLB-affected trees for ‘Hamlin’ and ‘Valencia’, respectively. Lower water use of HLB-affected trees resulted in 10% and 15% greater available soil water content than healthy ‘Hamlin’ and ‘Valencia’ trees, respectively. Therefore, reducing the water supply for HLB-affected trees than healthy trees may be a desirable practice that would lead to significant water savings.
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Wang, Jianping, Shujing Gao, Yueli Luo, and Dehui Xie. "Threshold Dynamics of a Huanglongbing Model with Logistic Growth in Periodic Environments." Abstract and Applied Analysis 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/841367.
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We analyze the impact of seasonal activity of psyllid on the dynamics of Huanglongbing (HLB) infection. A new model about HLB transmission with Logistic growth in psyllid insect vectors and periodic coefficients has been investigated. It is shown that the global dynamics are determined by the basic reproduction numberR0which is defined through the spectral radius of a linear integral operator. IfR0< 1, then the disease-free periodic solution is globally asymptotically stable and ifR0> 1, then the disease persists. Numerical values of parameters of the model are evaluated taken from the literatures. Furthermore, numerical simulations support our analytical conclusions and the sensitive analysis on the basic reproduction number to the changes of average and amplitude values of the recruitment function of citrus are shown. Finally, some useful comments on controlling the transmission of HLB are given.
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Ahmed Hassan Abdel Salam, Ahmed Hassan Abdel Salam. "Synthesis, Structural Chemistry, and Biological Studies on Various Divalent Copper Chelates of Novel Ligands Derived from Food Preservative, Dehydroacetic Acid, with Anilines." Journal of the chemical society of pakistan 41, no. 6 (2019): 1055. http://dx.doi.org/10.52568/000823/jcsp/41.06.2019.
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Various six coordinated copper(II) complexes of novel (E)-4-hydroxy-6-methyl-3-(1-(p-tolylimino) ethyl-2H-pyran-2-one (HL1) and (E)-3-(1-(4-chlorophenylimino) ethyl-4-hydroxy-6-methyl-2H-pyran-2-one (HL2) derived from 3-Acetyl-2-hydroxy-6-methyl-4H-pyran-4-one (dehydroacetic acid, DHA) and aniline derivatives (p-chloroaniline and p-toluidine) were fabricated. The coordination mode of Schiff base donor atoms with copper ions was well investigated by thermal and elemental analyses, FTIR, UV-vis, 1H, 13C-NMR spectral tools and measurements of magnetic susceptibility as well as molar conductance at ambient temperature. The novel neutral bidentate Schiff base ligands (HL1 and HL2) linked to Cu(II) cation via the azomethine-N and hydroxyl-O atoms and to acetate and nitrate anions in bidentate bridging mode to form polymeric octahedral complexes. The thermal study showed the stepwise removal of water of hydration and anions and decomposition of these chelates. The decomposition products were examined and the relative thermal stabilities of these chelates were evaluated. Different parameters of activation were derived from the thermal curves by Coats–Redfern methodology. The degradation steps of the metal complexes had positive free energy values indicating their non-spontaneous nature. The antifungal and antibacterial activities of all investigated compounds were also studied. The magnetic susceptibility measurements and conductance data were investigated and provided evidence for the non-electrolytic character of the complexes.
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Nisa, Khairun, Suryadi Islami, Erlin Listiyaningsih, Rizki Arisandi, and Azmi Adha Nurhaniefah. "Comparison of Red Blood Cell Parameters as Metabolic Indicator in Stunted and Nonstunted Children." International Journal of Nutrition, Pharmacology, Neurological Diseases 14, no. 2 (2024): 213–19. http://dx.doi.org/10.4103/ijnpnd.ijnpnd_1_24.
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Introduction: Stunting occurs as a result of chronic malnutrition, which triggers changes in metabolic function, which are usually characterized by impaired blood profiles in stunted children. This study aims to compare the red blood cell (RBC) Parameters in stunted and nonstunted children. Methods: This study used laboratory observational analytic methods with a cross-sectional approach. The study included a total of 74 participants aged 6–10 years. Primary data was collected by collecting sociodemographic data from the subjects, measuring anthropometric variables, and taking blood samples to analyze the erythrocyte index based on the hematological parameters of RBCs, including hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). Data analysis was performed using the one-way ANOVA test for erythrocytes, HGB, HCT, and Kruskal–Wallis for MCV, MCH, and MCHC at 95% confidence level. Result: The participants consisted of 33 males and 41 females. Based on the World Health Organization classification of anthropometric measurements, it was found that 46 children were normal, 18 were classified as stunting, and the remaining 10 were severe stunting. Conclusion: RBC parameter analysis based on hematological parameters found that in the male group, there were significantly lower RBC counts, HGB, HCT, MCH, and MCHC in stunting and severe stunting children compared to the nonstunted or normal children, whereas in the female group, the significant lower result found in the parameter of RBC counts, HGB, HCT, and MCV.
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Angel, Jorge Evelio, Erick Geovanni Hernández, Néstor Andrés Herrera, et al. "Comparison of DNA extraction methods for detection of citrus huanglongbing in Colombia." Agronomía Colombiana 32, no. 1 (2014): 7–13. http://dx.doi.org/10.15446/agron.colomb.v32n1.40544.
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Four DNA citrus plant tissue extraction protocols and three methods of DNA extraction from vector psyllid Diaphorina citriKuwayama (Hemiptera: Psyllidae) were compared as part of the validation process and standardization for detection of huanglongbing (HLB). The comparison was done using several criterias such as integrity, purity and concentration. The best quality parameters presented in terms of extraction of DNA from plant midribs tissue of citrus, were cited by Murray and Thompson (1980) and Rodríguez et al. (2010), while for the DNA extraction from psyllid vectors of HLB, the best extraction method was suggested by Manjunath et al.(2008).
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Taylor, Rachel A., Erin A. Mordecai, Christopher A. Gilligan, Jason R. Rohr, and Leah R. Johnson. "Mathematical models are a powerful method to understand and control the spread of Huanglongbing." PeerJ 4 (November 3, 2016): e2642. http://dx.doi.org/10.7717/peerj.2642.
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Huanglongbing (HLB), or citrus greening, is a global citrus disease occurring in almost all citrus growing regions. It causes substantial economic burdens to individual growers, citrus industries and governments. Successful management strategies to reduce disease burden are desperately needed but with so many possible interventions and combinations thereof it is difficult to know which are worthwhile or cost-effective. We review how mathematical models have yielded useful insights into controlling disease spread for other vector-borne plant diseases, and the small number of mathematical models of HLB. We adapt a malaria model to HLB, by including temperature-dependent psyllid traits, “flushing” of trees, and economic costs, to show how models can be used to highlight the parameters that require more data collection or that should be targeted for intervention. We analyze the most common intervention strategy, insecticide spraying, to determine the most cost-effective spraying strategy. We find that fecundity and feeding rate of the vector require more experimental data collection, for wider temperatures ranges. Also, the best strategy for insecticide intervention is to spray for more days rather than pay extra for a more efficient spray. We conclude that mathematical models are able to provide useful recommendations for managing HLB spread.