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1
Szymanowska, Urszula, Monika Karaś, and Justyna Bochnak-Niedźwiecka. "Antioxidant and Anti-Inflammatory Potential and Consumer Acceptance of Wafers Enriched with Freeze-Dried Raspberry Pomace." Applied Sciences 11, no. 15 (2021): 6807. http://dx.doi.org/10.3390/app11156807.
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In this study, the effect of the addition of freeze-dried raspberry pomace on the content of phenolic compounds and the antioxidant and anti-inflammatory activity of wafers was investigated. Particular attention was paid to the biological activity of the potentially bioavailable fraction of polyphenols extracted via gastro-intestinal digestion. In the basic recipe for the waffle dough, flour was replaced with freeze-dried raspberry pomace in the amount of 10%, 20%, 30%, 50%, and 75%. The content of total phenolic compounds, phenolic acids, flavonoids, and anthocyanins in ethanol and buffer extracts and after in vitro digestion increased with the increase in the addition of pomace. A similar relationship was noted for antioxidant properties: ability to neutralize ABTS—2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and DPPH—1,1-diphenyl-2-picrylhydrazyl radicals, iron II chelating ability, and reduction power. The extracts obtained after the simulated digestion showed the highest activities, which confirms that the polyphenols are a potentially bioavailable fraction. Extracts from the fortified wafers effectively inhibited the activity of enzymes involved in the generation of free radicals and induction of inflammation, i.e., xanthine oxidase (XO), lipoxygenase (LOX), and cyclooxygenase 2 (COX-2). The lowest IC50 values were determined for extracts after in vitro digestion. The sensory evaluation of the prepared wafers showed that the wafers fortified with 20% pomace achieved optimal scores. Enrichment of confectionery products with waste products from the fruit and vegetable industry can be a good way to increase the proportion of biologically active polyphenols in the diet and brings benefits to the environment.
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Majeed, Bivragh, Wim De Malsche, Lei Zhang, Paolo Fiorini, Deniz Sabuncuoglu Tezcan, and Philippe Soussan. "Silicon Micro-Fabrication Technologies for Micro-Filters." International Symposium on Microelectronics 2010, no. 1 (2010): 000498–504. http://dx.doi.org/10.4071/isom-2010-wa5-paper1.
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Silicon micro-fabrication techniques allow for the development of microfluidic systems with very accurate control of size and uniformity of structures. In this paper we report on the silicon fabrication process of micro-filters for versatile application in fluidics systems. Micro-filters are composed of an ordered array of pillars and supply channels. Depending on pillar pitch, they can be used for, e.g., electrophoresis, chromatography and purification of biological mixtures. In this paper we focus on high performance liquid chromatography. The process that we have developed for micropillar fabrication consists of defining first 1μm diameter pillars with an inter-pillar distance of 1μm or less in an oxide hard mask with a DUV stepper, stitching is used to form few cm long patterns across the 200mm wafers. Second, the supply channels are defined with 1× alignment lithography. After definition of supply channels, deep reactive ion etching of silicon is performed with an optimised recipe to etch submicron pillars and supply channels of 100μm wide at the same time. The simultaneous etch of both structures avoids complex lithography steps otherwise necessary to protect the pillars while etching the supply channels or vice versa as would be done conventionally. Wafers are then anodically bonded to 200mm Pyrex wafers in order to seal the channels. Pyrex wafer also allows the use of optical detection system. Feed through holes for accessing the supply channels are etched on the backside of Si wafer. Filter characterization has been performed: a plate height of 1μm was measured and successful separation of 3 coumarin dyes is achieved.
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Folch, A., A. Ayon, O. Hurtado, M. A. Schmidt, and M. Toner. "Molding of Deep Polydimethylsiloxane Microstructures for Microfluidics and Biological Applications." Journal of Biomechanical Engineering 121, no. 1 (1999): 28–34. http://dx.doi.org/10.1115/1.2798038.
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Here we demonstrate the microfabrication of deep (>25 μm) polymeric microstructures created by replica-molding polydimethylsiloxane (PDMS) from microfabricated Si substrates. The use of PDMS structures in microfluidics and biological applications is discussed. We investigated the feasibility of two methods for the microfabrication of the Si molds: deep plasma etch of silicon-on-insulator (SOI) wafers and photolithographic patterning of a spin-coated photoplastic layer. Although the SOI wafers can be patterned at higher resolution, we found that the inexpensive photoplastic yields similar replication fidelity. The latter is mostly limited by the mechanical stability of the replicated PDMS structures. As an example, we demonstrate the selective delivery of different cell suspensions to specific locations of a tissue culture substrate resulting in micropatterns of attached cells.
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Kim, Hyungjun, Hanmin Jang, Bongjoong Kim, et al. "Flexible elastomer patch with vertical silicon nanoneedles for intracellular and intratissue nanoinjection of biomolecules." Science Advances 4, no. 11 (2018): eaau6972. http://dx.doi.org/10.1126/sciadv.aau6972.
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Vertically ordered arrays of silicon nanoneedles (Si NNs), due to their nanoscale dimension and low cytotoxicity, could enable minimally invasive nanoinjection of biomolecules into living biological systems such as cells and tissues. Although production of these Si NNs on a bulk Si wafer has been achieved through standard nanofabrication technology, there exists a large mismatch at the interface between the rigid, flat, and opaque Si wafer and soft, curvilinear, and optically transparent biological systems. Here, we report a unique methodology that is capable of constructing vertically ordered Si NNs on a thin layer of elastomer patch to flexibly and transparently interface with biological systems. The resulting outcome provides important capabilities to form a mechanically elastic interface between Si NNs and biological systems, and simultaneously enables direct imaging of their real-time interactions under the transparent condition. We demonstrate its utility in intracellular, intradermal, and intramuscular nanoinjection of biomolecules into various kinds of biological cells and tissues at their length scales.
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Miki, Hiroko, Atsunobu Isobayashi, Tatsuro Saito, and Yoshiaki Sugizaki. "Ionic Liquids With Wafer-Scalable Graphene Sensors for Biological Detection." IEEE Transactions on NanoBioscience 18, no. 2 (2019): 216–19. http://dx.doi.org/10.1109/tnb.2019.2905286.
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Chen, Chong-You, Chang-Ming Wang, Hsiang-Hua Li, Hong-Hseng Chan, and Wei-Ssu Liao. "Wafer-scale bioactive substrate patterning by chemical lift-off lithography." Beilstein Journal of Nanotechnology 9 (January 26, 2018): 311–20. http://dx.doi.org/10.3762/bjnano.9.31.
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The creation of bioactive substrates requires an appropriate interface molecular environment control and adequate biological species recognition with minimum nonspecific attachment. Herein, a straightforward approach utilizing chemical lift-off lithography to create a diluted self-assembled monolayer matrix for anchoring diverse biological probes is introduced. The strategy encompasses convenient operation, well-tunable pattern feature and size, large-area fabrication, high resolution and fidelity control, and the ability to functionalize versatile bioarrays. With the interface-contact-induced reaction, a preformed alkanethiol self-assembled monolayer on a Au surface is ruptured and a unique defect-rich diluted matrix is created. This post lift-off region is found to be suitable for insertion of a variety of biological probes, which allows for the creation of different types of bioactive substrates. Depending on the modifications to the experimental conditions, the processes of direct probe insertion, molecular structure change-required recognition, and bulky biological species binding are all accomplished with minimum nonspecific adhesion. Furthermore, multiplexed arrays via the integration of microfluidics are also achieved, which enables diverse applications of as-prepared substrates. By embracing the properties of well-tunable pattern feature dimension and geometry, great local molecular environment control, and wafer-scale fabrication characteristics, this chemical lift-off process has advanced conventional bioactive substrate fabrication into a more convenient route.
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Berlova, E. V., V. A. Zhukova, N. V. Latukhina, and G. A. Pisarenko. "SPECTRAL INVESTIGATIONS OF NANOCOMPOSITES ON THE BASIS OF POROUS SILICON." Vestnik of Samara University. Natural Science Series 19, no. 3 (2017): 75–84. http://dx.doi.org/10.18287/2541-7525-2013-19-3-75-84.
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The results of experimental studies of porous silicon nanocomposites with biological materials: powder mineral phase of bone (hydroxyapatite) and biochemical solution identical to the natural tear fluid are presented in the work. Layers of porous silicon have been obtained in the process of electrochemical etching silicon wafers. There have been studies of IR reflection spectra of samples of nanocomposites in the range 4000-550 cm-1 produced.
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Knight, Shannon C., Bret A. Unger, and Kurt W. Kolasinski. "Crystallographically Defined Silicon Macropore Membranes." Open Material Sciences 4, no. 1 (2018): 33–41. http://dx.doi.org/10.1515/oms-2018-0004.
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Abstract Laser ablation with nanosecond-pulsed Nd:YAG laser irradiation combined with anisotropic alkaline etching of Si wafers creates 4-20 μm macropores that extend all the way through the wafer. The walls of these macropores are crystallographically defined by the interaction of the anisotropy of the etchant with the orientation of the single-crystal silicon substrate: rectangular/octagonal on Si(001), parallelepiped on Si(110), triangular/hexagonal on Si(111). Laser ablation can create pillars with peak-tovalley heights of over 100 μm. However, with nanosecondpulsed irradiation at 532 nm, the majority of this height is created by growth above the original plane of the substrate whereas for 355 nm irradiation, the majority of the height is located below the initial plane of the substrate. Repeated cycles of ablation and alkaline etching are required for membrane formation. Therefore, irradiating with 355 nm maintained better the crystallographically defined nature of the through-pores whereas irradiation at 532 nm led to more significant pore merging and less regularity in the macropore shapes. Texturing of the substrates with alkaline-etching induced pyramids or near-field modulation of the laser intensity by diffraction off of a grid or grating is used to modulate the growth of ablation pillars and the resulting macropores. Texturing causes the macropores to be more uniform and significantly improves the yield of macropores. The size range of these macropores may make them useful in single-cell biological studies.
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Dekeyser, C. M., C. C. Buron, S. R. Derclaye, A. M. Jonas, J. Marchand-Brynaert, and P. G. Rouxhet. "Degradation of bare and silanized silicon wafer surfaces by constituents of biological fluids." Journal of Colloid and Interface Science 378, no. 1 (2012): 77–82. http://dx.doi.org/10.1016/j.jcis.2012.04.022.
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Song, Enming, Chia-Han Chiang, Rui Li, et al. "Flexible electronic/optoelectronic microsystems with scalable designs for chronic biointegration." Proceedings of the National Academy of Sciences 116, no. 31 (2019): 15398–406. http://dx.doi.org/10.1073/pnas.1907697116.
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Flexible biocompatible electronic systems that leverage key materials and manufacturing techniques associated with the consumer electronics industry have potential for broad applications in biomedicine and biological research. This study reports scalable approaches to technologies of this type, where thin microscale device components integrate onto flexible polymer substrates in interconnected arrays to provide multimodal, high performance operational capabilities as intimately coupled biointerfaces. Specificially, the material options and engineering schemes summarized here serve as foundations for diverse, heterogeneously integrated systems. Scaled examples incorporate >32,000 silicon microdie and inorganic microscale light-emitting diodes derived from wafer sources distributed at variable pitch spacings and fill factors across large areas on polymer films, at full organ-scale dimensions such as human brain, over ∼150 cm2. In vitro studies and accelerated testing in simulated biofluids, together with theoretical simulations of underlying processes, yield quantitative insights into the key materials aspects. The results suggest an ability of these systems to operate in a biologically safe, stable fashion with projected lifetimes of several decades without leakage currents or reductions in performance. The versatility of these combined concepts suggests applicability to many classes of biointegrated semiconductor devices.
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Nagano, T., Mutsumi Touge, and Junji Watanabe. "Thinning Technology of Patterned Silicon Wafer for Micro Pressure Sensor." Key Engineering Materials 291-292 (August 2005): 419–24. http://dx.doi.org/10.4028/www.scientific.net/kem.291-292.419.
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Recently, the research of the gene using the transgenic mouse has been performed for the development of new medicines. However, 600,000 kinds of mice are produced for the elucidation of each gene function. For this reason, the intelligent microchips have been developed to obtain an individual identification and biological information. The ventricular rate of a mouse can be monitored by the micro pressure sensor mounted on the intelligent microchip. In this research, the detailed structure and functions of the micro pressure sensor were investigated by the FEM analysis, and the sensor-chips were manufactured on 6-inch silicon wafer. The wafer thickness had to be reduced owing to the size restriction of the intelligent microchip. The grinding of the 6-inch silicon wafer with 560 µm in thickness with 19200 sensor-chips was carried out by the newly developed thinning technology. After the basic characteristics of a sensor-chip were evaluated, the output profile containing small peaks corresponding to the heartbeat of a transgenic mouse was finally detected using a mounted sensor-chip.
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Yang, Fan, Jun Li, Yin Long, et al. "Wafer-scale heterostructured piezoelectric bio-organic thin films." Science 373, no. 6552 (2021): 337–42. http://dx.doi.org/10.1126/science.abf2155.
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Piezoelectric biomaterials are intrinsically suitable for coupling mechanical and electrical energy in biological systems to achieve in vivo real-time sensing, actuation, and electricity generation. However, the inability to synthesize and align the piezoelectric phase at a large scale remains a roadblock toward practical applications. We present a wafer-scale approach to creating piezoelectric biomaterial thin films based on γ-glycine crystals. The thin film has a sandwich structure, where a crystalline glycine layer self-assembles and automatically aligns between two polyvinyl alcohol (PVA) thin films. The heterostructured glycine-PVA films exhibit piezoelectric coefficients of 5.3 picocoulombs per newton or 157.5 × 10−3 volt meters per newton and nearly an order of magnitude enhancement of the mechanical flexibility compared with pure glycine crystals. With its natural compatibility and degradability in physiological environments, glycine-PVA films may enable the development of transient implantable electromechanical devices.
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Wirkert, Florian J., Michael Paulus, Julia Nase, et al. "X-ray reflectivity measurements of liquid/solid interfaces under high hydrostatic pressure conditions." Journal of Synchrotron Radiation 21, no. 1 (2013): 76–81. http://dx.doi.org/10.1107/s1600577513021516.
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A high-pressure cell forin situX-ray reflectivity measurements of liquid/solid interfaces at hydrostatic pressures up to 500 MPa (5 kbar), a pressure regime that is particularly important for the study of protein unfolding, is presented. The original set-up of this hydrostatic high-pressure cell is discussed and its unique properties are demonstrated by the investigation of pressure-induced adsorption of the protein lysozyme onto hydrophobic silicon wafers. The presented results emphasize the enormous potential of X-ray reflectivity studies under high hydrostatic pressure conditions for thein situinvestigation of adsorption phenomena in biological systems.
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Rafferty, Conor, Mitul Dalal, Dan Davis, et al. "Epidermal electronics for health and fitness monitoring." International Symposium on Microelectronics 2012, no. 1 (2012): 000156–61. http://dx.doi.org/10.4071/isom-2012-ta53.
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Medical deployment of electronics is frequently hampered by boxy, rigid packaging. Biological tissues are soft and curved, while electronic components are hard and angular. The mechanical mismatch can be alleviated by re-packaging electronics in radical new form factors. MC10 has developed a technology platform using ultra-thin components linked with stretchable interconnects and embedded in low modulus polymers which provide an excellent match to biological tissues. The MC10 platform is based on packaging today's high-performance active components in new mechanical form factors. The platform has three key elements: thin silicon embedded in film for flexibility, silicon transfer from foundry CMOS wafers to polymer-coated carriers and flexible metallic interconnect on polymer. On-body and in-body applications are both well suited to the technology platform. Skin-mounted systems resemble electronic tattoos, and can be worn for extended periods without discomfort while providing continuous monitoring. Inside the body, instrumented catheters provide a practitioner with unprecedented electrical information about the interior of the heart.
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El-Hamshary, Hany, Mehrez E. El-Naggar, Ayman El-Faham, M. A. Abu-Saied, M. K. Ahmed, and Mosaed Al-Sahly. "Preparation and Characterization of Nanofibrous Scaffolds of Ag/Vanadate Hydroxyapatite Encapsulated into Polycaprolactone: Morphology, Mechanical, and In Vitro Cells Adhesion." Polymers 13, no. 8 (2021): 1327. http://dx.doi.org/10.3390/polym13081327.
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Series of nanofibrous composites of polycaprolactone (PCL) were fabricated in different compositions of modified hydroxyapatite (HAP). The encapsulated HAP was co-doped with Ag/vanadate ions at different Ag contributions. XRD and FTIR techniques confirmed the powder and fibrous phase formation. Further, the morphological and mechanical behaviors of the electrospun nanofibrous scaffolds containing hydroxyapatite were investigated. The nanofibrous phases were biologically evaluated via studying contact angle, antibacterial, cell viability, and in vitro growth of human fibroblasts cell line (HFB4). It is obvious that silver ions cause gradual deviation in powder grains from wafer-like to cloudy grains. The maximum height of the roughness (Rt) ranged from 902.0 to 956.9 nm, while the valley depth of the roughness (Rv) ranged from 308.3 to 442.8 nm, for the lowest and the highest additional Ag ions for powdered phases. Moreover, the highest contribution of silver through the nanofibrous phases leads to the formation of lowest filaments size ranged from 0.07 to 0.53 µm. Further, the fracture strength was increased exponentially from 2.51 ± 0.35 MPa at zero concentration of silver ions up to 4.23 ± 0.64 MPa at 0.6 Ag/V-HAP@PCL. The fibrous phases were biologically evaluated in terms of antibacterial, cell viability, and in vitro growth of human fibroblasts cell line (HFB4). The nanofibrous composition of 0.8 Ag/V-HAP@PCL reached the maximum potential against E. coli and S. aureus and recorded 20.3 ± 1.1 and 19.8 ± 1.2 mm, respectively. This significant performance of the antibacterial activity and cell viability of co-doped HAP distributed through PCL could recommend these compositions for more research in biological applications, including wound healing.
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Singh, Tripti, and Colleen Chittenden. "Synergistic Ability of Chitosan and Trichoderma harzianum to Control the Growth and Discolouration of Common Sapstain Fungi of Pinus radiata." Forests 12, no. 5 (2021): 542. http://dx.doi.org/10.3390/f12050542.
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An environmentally compatible method for controlling sapstain fungi in wood was evaluated, using a combination of chitosan and an albino strain of Trichoderma harzianum, a biological control agent (BCA). The growth and penetration into the wood of the sapstain fungi Ophiostoma piceae, Leptographium procerum, and Sphaeropsis sapinea were assessed in radiata pine wafers treated with chitosan and BCA, both alone and in combination. Several mycological and microscopic techniques were used, including a gfp (green fluorescent protein) transformed strain of O. piceae for assessing the depth of penetration in the wood samples. The synergy between the chitosan and BCA was evident, and for two tested fungi, only the combination of chitosan and BCA afforded protection. The synnemata (recognized by erect conidiogenous cells bearing conidia) was observed on the surface of the wafers inoculated with L. procerum and O. piceae, but the hyphae were unable to penetrate and melanise. The results suggest that the limited ability of chitosan to penetrate deeply into the wood was compensated by the fast growth of T. harzianum in the inner wood.
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Tintelott, Marcel, Vivek Pachauri, Sven Ingebrandt, and Xuan Thang Vu. "Process Variability in Top-Down Fabrication of Silicon Nanowire-Based Biosensor Arrays." Sensors 21, no. 15 (2021): 5153. http://dx.doi.org/10.3390/s21155153.
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Silicon nanowire field-effect transistors (SiNW-FET) have been studied as ultra-high sensitive sensors for the detection of biomolecules, metal ions, gas molecules and as an interface for biological systems due to their remarkable electronic properties. “Bottom-up” or “top-down” approaches that are used for the fabrication of SiNW-FET sensors have their respective limitations in terms of technology development. The “bottom-up” approach allows the synthesis of silicon nanowires (SiNW) in the range from a few nm to hundreds of nm in diameter. However, it is technologically challenging to realize reproducible bottom-up devices on a large scale for clinical biosensing applications. The top-down approach involves state-of-the-art lithography and nanofabrication techniques to cast SiNW down to a few 10s of nanometers in diameter out of high-quality Silicon-on-Insulator (SOI) wafers in a controlled environment, enabling the large-scale fabrication of sensors for a myriad of applications. The possibility of their wafer-scale integration in standard semiconductor processes makes SiNW-FETs one of the most promising candidates for the next generation of biosensor platforms for applications in healthcare and medicine. Although advanced fabrication techniques are employed for fabricating SiNW, the sensor-to-sensor variation in the fabrication processes is one of the limiting factors for a large-scale production towards commercial applications. To provide a detailed overview of the technical aspects responsible for this sensor-to-sensor variation, we critically review and discuss the fundamental aspects that could lead to such a sensor-to-sensor variation, focusing on fabrication parameters and processes described in the state-of-the-art literature. Furthermore, we discuss the impact of functionalization aspects, surface modification, and system integration of the SiNW-FET biosensors on post-fabrication-induced sensor-to-sensor variations for biosensing experiments.
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Bao, Juncheng, Tomislav Markovic, Luigi Brancato, et al. "Novel Fabrication Process for Integration of Microwave Sensors in Microfluidic Channels." Micromachines 11, no. 3 (2020): 320. http://dx.doi.org/10.3390/mi11030320.
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This paper presents a novel fabrication process that allows integration of polydimethylsiloxane (PDMS)-based microfluidic channels and metal electrodes on a wafer with a micrometer-range alignment accuracy. This high level of alignment accuracy enables integration of microwave and microfluidic technologies, and furthermore accurate microwave dielectric characterization of biological liquids and chemical compounds on a nanoliter scale. The microfluidic interface between the pump feed lines and the fluidic channels was obtained using magnets fluidic connection. The tube-channel interference and the fluidic channel-wafer adhesion was evaluated, and up to a pressure of 700 mBar no leakage was observed. The developed manufacturing process was tested on a design of a microwave-microfluidic capacitive sensor. An interdigital capacitor (IDC) and a microfluidic channel were manufactured with an alignment accuracy of 2.5 μm. The manufactured IDC sensor was used to demonstrate microwave dielectric sensing on deionized water and saline solutions with concentrations of 0.1, 0.5, 1, and 2.5 M.
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Tague, Thomas J., and Lisa M. Miller. "Novel Use of Fluorescence Illumination with an Infrared Microscope." Microscopy Today 8, no. 2 (2000): 26–33. http://dx.doi.org/10.1017/s1551929500057473.
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It has become increasingly obvious that infrared microspectroscopy can be the analysis tool of choice when determining the chemical composition of biological and biomedical samples. Frequently, fluorescence illumination is required for sample characterization, which previously required the use of a separate optical microscope. There has also been a need in the semiconductor manufacturing industry for a single tool for visualizing particle contaminants on integrated wafers as well as the ability to chemically determine their nature. There is now a single microscope platform for conducting rapid Nomarski differential interference contrast and fluorescence illumination sample visualization as well as infrared analysis. This novel infrared microscope has applicability to many fields of investigation, including pharmacology, forensics, cell biology, histology, gemology, and geology.
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López-Garro, Andrés, Ilena Zanella, Geiner Golfín-Duarte, and Maikel Pérez-Montero. "Residencia del tiburón punta blanca de arrecife, Triaenodon obesus, (Carcharhiniformes: Carcharhinidae) en las bahías Chatham y Wafer del Parque Nacional Isla del Coco, Costa Rica." Revista de Biología Tropical 68, S1 (2020): S330—S339. http://dx.doi.org/10.15517/rbt.v68is1.41203.
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Introducción: El tiburón punta blanca (Triaenodon obesus) es una especie de arrecife de aguas tropicales, no migratoria, que ha demostrado no tener una alta conectividad costera, como la observada para otras especies de tiburón, sin embargo posee la distribución más amplia de todas las demás especies de tiburón de arrecife del Indo-Pacífico. T. obesus, es una de las especies de tiburón más comunes en el Parque Nacional Isla del Coco (PNIC), y no presenta una estacionalidad marcada. En las bahías localizadas en el norte del PNIC, Bahía Chatham y Bahía Wafer, reside una saludable población del tiburón punta blanca de arrecife. A pesar de ser una especie abundante en las bahías Chatham y Wafer del PNIC, la información sobre su residencia resulta escaza. Objetivo: Conocer sobre el uso de hábitat y los movimientos del tiburón punta blanca de arrecife mejorará su manejo en el PNIC y en otros lugares del Pacífico Tropical Oriental. Para esto se realizó un estudio preliminar sobre la residencia en las bahías Chatham y Wafer del PNIC, utilizando telemetría acústica. Métodos: Se realizó una expedición de marcaje de tiburones al Parque Nacional Isla del Coco entre el 25 de noviembre al 5 de diciembre del 2014. Durante esta expedición se realizaron 2 giras nocturnas entre las 18:00 y las 22:00 a Bahía Chatham y Bahía Wafer y se marcaron 8 individuos de T. obesus con telemetría acústica y se instalaron dos receptores, uno en cada bahía. Resultados: Entre noviembre 2014 y diciembre 2015 los tiburones punta blanca marcados fueron detectados por los receptores instalados en las bahías en un total de 278 706 ocasiones. Los tiburones T. obesus marcados permanecieron largos periodos en las bahías Chatham y Wafer, El índice de Residencia (IR) medio de los T. obesus marcados fue de 0.97±0,03, reportando una tendencia en la baja del número total de detecciones durante las horas nocturnas. Los tiburones punta blanca de arrecife mostraron una alta fidelidad al sitio de marcaje, que se ve reflejado en los elevados índices de residencia reportados, particularmente altos en comparación con otras especies de tiburón de arrecife. Las detecciones de los tiburones en las bahías tienden a disminuir a partir de las 18:00 horas, cuando el tiburón punta blanca se vuelve activo para cazar en el arrecife. Conclusiones: En conclusión, los tiburones punta blanca poseen una alta residencia y fidelidad, lo cual confirma su bajo rango de hogar. El Área Marina Protegida de la Isla del Coco probablemente brinda una protección efectiva a la población del tiburón punta blanca de la pesca ilegal.
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Zhu, Xiaohua, Maoxia Chen, Xin He, Zili Xiao, Houzhen Zhou, and Zhouliang Tan. "Bioaugmentation treatment of PV wafer manufacturing wastewater by microbial culture." Water Science and Technology 72, no. 5 (2015): 754–61. http://dx.doi.org/10.2166/wst.2015.273.
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The wastewater of silicon photovoltaic (PV) battery manufacturing contained polyethylene glycol (PEG) and detergents, which possessed the characteristics of high content of organics and low bioavailability, and then resulted in high treatment costs. To address the difficulties of existing treatment facilities in stably meeting discharge standards, eight tons of microbial culture (consisting of Bacillus sp. and Rhodococcus sp.) were added into the aerobic treatment unit. Subsequently, the effectiveness of the microbial culture in small-scale biological wastewater treatment was evaluated, and the operating conditions for engineering applications were optimized. The application study showed that the average chemical oxygen demand (COD) removal efficiency reached 95.0% when the pH value was 7, the gas–water ratio was 28:1, the reflux ratio was 50%, which indicated an increase of 51.2% contrasting with the situation without bioaugmentation. The volume load of the treatment facilities after augmentation increased by 127.9% and could tolerate the COD shock load reached 2,340 mg · L−1. At last, the effluence met the class I standard of the Integrated Wastewater Discharge Standard (GB8978–1996).
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Lamberti, Annalisa, Carmen Sanges, Nunzia Migliaccio, et al. "Silicon-Based Technology for Ligand-Receptor Molecular Identification." Journal of Atomic, Molecular, and Optical Physics 2012 (January 11, 2012): 1–5. http://dx.doi.org/10.1155/2012/948390.
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One of the most important goals in the fields of biology and medicine is the possibility to dispose of efficient tools for the characterization of the extraordinary complexity of ligand-receptor interactions. To approach this theme, we explored the use of crystalline silicon (cSi) technology for the realization of a biotechnological device in which the ligand-receptor interactions are revealed by means of optical measurements. Here, we describe a chemical procedure for the functionalization of microwell etched on silicon wafers, and the subsequent anchoring of biological molecules like an antibody anti-A20 murine lymphoma cell line. The optical analysis of the interaction on the biochips between the bound biomolecule and their corresponding ligand indicated that the functionalized cSi is suitable for this application.
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Hemben, Aver, Iva Chianella, and Glenn John Thomas Leighton. "Surface Engineered Iron Oxide Nanoparticles Generated by Inert Gas Condensation for Biomedical Applications." Bioengineering 8, no. 3 (2021): 38. http://dx.doi.org/10.3390/bioengineering8030038.
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Despite the lifesaving medical discoveries of the last century, there is still an urgent need to improve the curative rate and reduce mortality in many fatal diseases such as cancer. One of the main requirements is to find new ways to deliver therapeutics/drugs more efficiently and only to affected tissues/organs. An exciting new technology is nanomaterials which are being widely investigated as potential nanocarriers to achieve localized drug delivery that would improve therapy and reduce adverse drug side effects. Among all the nanocarriers, iron oxide nanoparticles (IONPs) are one of the most promising as, thanks to their paramagnetic/superparamagnetic properties, they can be easily modified with chemical and biological functions and can be visualized inside the body by magnetic resonance imaging (MRI), while delivering the targeted therapy. Therefore, iron oxide nanoparticles were produced here with a novel method and their properties for potential applications in both diagnostics and therapeutics were investigated. The novel method involves production of free standing IONPs by inert gas condensation via the Mantis NanoGen Trio physical vapor deposition system. The IONPs were first sputtered and deposited on plasma cleaned, polyethylene glycol (PEG) coated silicon wafers. Surface modification of the cleaned wafer with PEG enabled deposition of free-standing IONPs, as once produced, the soft-landed IONPs were suspended by dissolution of the PEG layer in water. Transmission electron microscopic (TEM) characterization revealed free standing, iron oxide nanoparticles with size < 20 nm within a polymer matrix. The nanoparticles were analyzed also by Atomic Force Microscope (AFM), Dynamic Light Scattering (DLS) and NanoSight Nanoparticle Tacking Analysis (NTA). Therefore, our work confirms that inert gas condensation by the Mantis NanoGen Trio physical vapor deposition sputtering at room temperature can be successfully used as a scalable, reproducible process to prepare free-standing IONPs. The PEG- IONPs produced in this work do not require further purification and thanks to their tunable narrow size distribution have potential to be a powerful tool for biomedical applications.
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Emter, Othniel, and Bernd Mechler. "Bacillus thuringiensis var.israelensis:— Eine neue Waffe im Kampf gegen Stechmücken." Biologie in unserer Zeit 17, no. 3 (1987): 79–83. http://dx.doi.org/10.1002/biuz.19870170305.
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Liao, Yunn Shiuan, and Wen Yang Peng. "Study of Hole-Machining on Pyrex Wafer by Electrochemical Discharge Machining (ECDM)." Materials Science Forum 505-507 (January 2006): 1207–12. http://dx.doi.org/10.4028/www.scientific.net/msf.505-507.1207.
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The gap control problem in hole-machining of Pyrex® wafer by electrochemical discharge machining (ECDM) to obtain a smooth quality and acceptable material removal rate is studied. Analysis of the pulse signals shows that the average current pulse interval is constant, and it is mainly related to the ion translation conditions, such as the electrolyte concentration and the flushing strategy. The most steady and intense average current density can be obtained if the voltage on-time is around 3 times the average current pulse interval and the voltage off-time is 1/4 of the on-time for bubble film dissipation. The utmost allowable feed rate at each depth is recorded as the reference of the feed rate in real continuous machining to avoid the damage to the wafer. By applying 80% of the extreme allowable feed rate, 99.9% quality-proved holes can be acquired. The diametric error at the entrance or exit is within 6%. Besides, there is no crater-like problem around the hole that facilitates the succeeding bonding process. This study contributes to the successful production of reusable optical biological chips with integrated micro fluidic channels.
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Vargas, José L., and Eric J. Alfaro. "Ultraviolet radiation at Isla del Coco (Cocos Island) National Park, Costa Rica." Revista de Biología Tropical 64, no. 1 (2016): 75. http://dx.doi.org/10.15517/rbt.v64i1.23412.
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<p>Incoming solar energy that reaches the land surface is divided mainly in infrared, visible and UV. UV radiation has wave lengths from 100 to 400 nm. The World Health Organization recommends studies and monitoring of UV radiation because of its biological effects in living organisms.<strong> </strong>The use of automatic Davis weather stations, Vantage Pro Plus/Vantage Pro2 Plus type, with a sensor model 6490, allowed UV radiation measurements at Isla del Coco, Costa Rica, located in the Eastern Tropical Pacific. The stations were set near Chatham Bay (5°32’51” N - 87°02’43” W, 142 m.a.s.l) and Wafer Bay (5°32’24” N - 87°03’26” W, 132 m.a.s.l). Measurements were recorded: Apr. 5-11, 2008, Mar. 1-6, 2009, Apr. 22-27, 2010, Jul. 2-8, 2011 and Mar. 15-21, 2012. Data were described for the cloudiest and sunniest days according to the UV index (UVI) as a standardized value that allows easy data interpretation in terms of the hazard exposure for living beings. This is especially important for coral reefs (the island has the largest Pacific reefs in Costa Rica). The maximum UVI average range in Chatham decrease from 14 for sunny days to 3 for cloudy days, and from 16 to 4 for the sunniest and cloudiest days, respectively. In Wafer, these values were 12 to 4 and 14.2 to 3.0, respectively. The average exposure to UV radiation was considered high for sunny days from 9:30 to 14:30hr in Chatham and from 10:00 to 14:30 in Wafer, but these values for the sunniest days increase from 9:00 to 15:00 in Chatham and from 9:00 to 14:30 in Wafer. The equipment used was able to identify events with extremely high UVI values during the expeditions. The generation and use of this information is useful for understanding and modeling the ecosystem dynamics, and it is also valuable for the rangers’ work and for the tourism sector.</p><div> </div>
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Punbusayakul, Niramol, Lijie Ci, Saikat Talapatra, Werasak Surareungchai, and Pulickel M. Ajayan. "Ultralong Aligned Multi-Walled Carbon Nanotube for Electrochemical Sensing." Journal of Nanoscience and Nanotechnology 8, no. 4 (2008): 2085–90. http://dx.doi.org/10.1166/jnn.2008.060.
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We have investigated electrochemical sensing properties of electrodes fabricated with ultralong aligned multi-walled carbon nanotube (MWNT) bundles synthesized using water-assisted chemical vapor deposition on aluminum (Al) and iron (Fe) coated silicon wafer with ethylene and argon/hydrogen gas as carbon source and buffer gas respectively. Cyclic voltammograms performed on these electrodes show diffusion-controlled-reversible reaction. The dominance of radial diffusion mass transport at these electrodes was also indicated by sigmoidal-shaped voltammograms obtained at various scan rates. These electrodes were able to sense very low concentration of ascorbic acid (∼0.7 μM) and dopamine (∼1.87 μM), two model species often used in electro-analysis. The excellent electrochemical properties along with good single species detection ability suggest that these MWNTs are promising electrode materials for developing very sensitive chemical and/or biological sensors.
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Malik, M. Rizwan, Tie Lin Shi, Zi Rong Tang, and M. Haseeb. "A Boost-Up Method of MEMS-Bulk-Micromachining towards C-MEMS Fabrication for Sensing and Manipulating Bioparticles." Defect and Diffusion Forum 316-317 (May 2011): 59–67. http://dx.doi.org/10.4028/www.scientific.net/ddf.316-317.59.
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Much of the recent ongoing advanced research into the quest for improved etching techniques has brought forth a broad concept for the fabrication of micro/nano-electromechanical systems (MEMS/NEMS) having high accuracy, precision, efficiency, compatibility and through-put of metallic- as well as carbon-composition structural phases. This in turn leads towards a thorough understanding of the sensing, trapping, separating, controlling, positioning, directing, concentrating and manipulating of micro-nano-sized particles - predominantly biological particles - in the emerging MEMS/NEMS technological field. This paper focuses its attention on the easiest means of wet-etching {100}-type silicon wafer surfaces by guiding the choice of [<100> or <010>] orientation (at 45° to the normal orientation). This anisotropic etching is performed in KOH solution. Here, consideration is not concerned to a large extent with process parameters as in anodic oxidation, an intensely doped boron etching stops and silicon wafer surface back-etching. The main concern of the present practical application route involves a passivating material (silicon dioxide, SiO2) and two masking stages (for a two-step etching process). As a example of this method, silicon cantilever beams having vertical edges are produced. It is concluded that the method presented will be helpful in the comprehensive study of resonators, pressure/temperature sensors, three-dimensional carbon micro-electrodes, actuators and accelerometers for bioparticle applications.
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Adatia, Adil, Dan Johnson, and Susan Entz. "Pathogenicity of two new isolates of Metarhizium anisopliae from Canadian soil to Melanoplus bivittatus (Orthoptera: Acrididae) and Tenebrio molitor (Coleoptera: Tenebrionidae)." Canadian Entomologist 142, no. 2 (2010): 128–34. http://dx.doi.org/10.4039/n09-041.
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AbstractWorldwide biological-control research has shown that the fungal entomopathogen Metarhizium anisopliae (Metschnikoff) is an alternative to chemical insecticides for controlling grasshoppers and locusts. The pathogenicity of two recently discovered isolates of M. anisopliae var. anisopliae Driver and Milner from Canadian soil to the key grasshopper pest Melanoplus bivittatus (Say) and the yellow mealworm, Tenebrio molitor L., was determined by means of laboratory bioassays. Insects were fed a single dose of 105 conidia suspended in sunflower oil on food (a standard-size lettuce wafer). Subsequent feeding activity, movement, and mortality were assessed daily. The isolates were equally pathogenic, and similar in pathogenicity to the industry standard, Green Guard (M. anisopliae var. acridum Driver and Milner). Treatment with the three isolates resulted in 50% grasshopper mortality in 5–6 days and 90% mortality in 6–7 days.
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Pancera, S. M., H. Gliemann, D. F. S. Petri, and T. Schimmel. "Adsorption Behaviour of Creatine Phosphokinase onto Silicon Wafers: Comparison between Ellipsometric and Atomic Force Microscopy Data." Microscopy and Microanalysis 11, S03 (2005): 56–60. http://dx.doi.org/10.1017/s1431927605050889.
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Protein adsorption plays a major role in a variety of important technological and biological processes [1-2] and the understanding of the fundamental factors that determine protein adsorption are imperative to the development of biocompatible materials and biotechnological devices [3-4] as for example biosensors [5]. The adsorption of proteins on surfaces is a complex process. Due to the large size and different shapes of these adsorbing particles, the interactions between the adsorbed proteins on the surface can be strongly influentiated by the fact that the particles may undergo conformational changes upon adsorption [6-7]. In a previous work the adsorption behaviour of creatine phosphokinase (CPK) onto hydrophilic (silicon wafers and amino-terminated surfaces) and hydrophobic (Polystyrene, PS, coated wafers) substrates was investigated by means of null-ellipsometry and contact angle measurements [8]. This previous ellipsometric study led to a model, where CPK adsorption takes place in four stages: (i) a diffusive one, where all the arriving biomolecules are immediately adsorbed; (ii) the arriving biomolecules might stick on the latter and afterward diffuse to the free sites on the substrate, followed by conformational changes [6-7], (iii) formation of a monolayer and (iv) continuous and irreversible adsorption. A multilayer system might be formed, as well as aggregation processes might play a role at this stage. In this work Atomic Force Microscopy (AFM) measurements under water were done in order to confirm this four steps model and to observe changes in the film topography and homogeneity along the adsorption process. The thickness of the adsorbed CPK biofilm obtained by ellipsometry was also compared with that obtained by the wet AFM method.
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Aday, Aaron W., Edward K. Duran, Martin Van Denburgh, et al. "Homocysteine Is Associated With Future Venous Thromboembolism in 2 Prospective Cohorts of Women." Arteriosclerosis, Thrombosis, and Vascular Biology 41, no. 7 (2021): 2215–24. http://dx.doi.org/10.1161/atvbaha.121.316397.
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Objective: Case-control studies have identified plasma homocysteine as a risk marker for venous thromboembolism (VTE). Prospective data, particularly among women, are sparse. We examined whether plasma homocysteine associates with incident VTE in 2 large prospective cohorts of women. Approach and Results: In the WHS (Women’s Health Study), a prospective cohort study of 27 555 women ≥45 years old and free of cardiovascular disease and VTE, we assessed baseline homocysteine concentration along with other thrombotic biomarkers for association with future VTE (n=743), pulmonary embolism (n=363), and deep vein thrombosis (n=545). We used a second cohort of 2672 women (n=102 VTE events) in the WAFACS (Women’s Antioxidant and Folic Acid Cardiovascular Study) to corroborate our findings. In age-adjusted analyses, elevated homocysteine, hsCRP (high-sensitivity C-reactive protein), fibrinogen, and sICAM-1 (soluble intercellular adhesion molecule-1) were associated with incident VTE ( P for extreme quartile comparisons and P -trend <0.05). In multivariable models adjusting for body mass index and other traditional VTE risk factors, only the association for homocysteine persisted (HR Q4 , 1.31 [95% CI, 1.06–1.63]). Elevated homocysteine levels were associated with unprovoked pulmonary embolism (HR Q4 , 2.13 [95% CI, 1.30–3.51]) and deep vein thrombosis (HR Q4 , 1.59 [95% CI, 1.05–2.40]) but not provoked events. In WAFACS, elevated homocysteine levels were also associated with VTE events ( P -trend 0.023). Conclusions: Higher plasma homocysteine levels associate with VTE events in 2 cohorts of middle-aged and older women. Among VTE subtypes, homocysteine was associated with unprovoked, but not provoked, events. These data suggest a plausible biological role for homocysteine in the development of VTE. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT00000479, NCT00000541.
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Tsay, Y. G., C. I. Lin, J. Lee, et al. "Optical biosensor assay (OBA)." Clinical Chemistry 37, no. 9 (1991): 1502–5. http://dx.doi.org/10.1093/clinchem/37.9.1502.
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Abstract We describe a new biosensor immunoassay involving optical diffraction to detect clinically important analytes in human body fluids. A silicon wafer is used as a support for immobilization of antigen or antibody. The protein-coated surface is illuminated through a photo mask to create distinct periodic areas of active and inactive protein. When the surface is incubated with a positive sample, antigen-antibody binding occurs only on the active areas. Upon illumination with a light source such as a laser, the resulting biological diffraction grating diffracts the light. A negative sample does not result in diffraction because no antigen-antibody binding occurs to create the diffraction grating. The presence or absence of a diffraction signal differentiates between positive and negative samples, and the intensity of the signal provides a quantitative measure of the analyte concentration. The technique is demonstrated with a quantitative assay of choriogonadotropin in serum.
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Alven, Sibusiso, and Blessing Atim Aderibigbe. "Chitosan and Cellulose-Based Hydrogels for Wound Management." International Journal of Molecular Sciences 21, no. 24 (2020): 9656. http://dx.doi.org/10.3390/ijms21249656.
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Wound management remains a challenge worldwide, although there are several developed wound dressing materials for the management of acute and chronic wounds. The wound dressings that are currently used include hydrogels, films, wafers, nanofibers, foams, topical formulations, transdermal patches, sponges, and bandages. Hydrogels exhibit unique features which make them suitable wound dressings such as providing a moist environment for wound healing, exhibiting high moisture content, or creating a barrier against bacterial infections, and are suitable for the management of exuding and granulating wounds. Biopolymers have been utilized for their development due to their non-toxic, biodegradable, and biocompatible properties. Hydrogels have been prepared from biopolymers such as cellulose and chitosan by crosslinking with selected synthetic polymers resulting in improved mechanical, biological, and physicochemical properties. They were useful by accelerating wound re-epithelialization and also mimic skin structure, inducing skin regeneration. Loading antibacterial agents into them prevented bacterial invasion of wounds. This review article is focused on hydrogels formulated from two biopolymers—chitosan and cellulose—for improved wound management.
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Apkarian, Robert P., Jonathan A. Tarr, Myron J. Kaufmann, and Fredric M. Menger. "High magnification in-lens field emission SE-I SEM of carbon based styrenes, diamonds, and endothelial cell membranes." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 860–61. http://dx.doi.org/10.1017/s0424820100140671.
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High resolution topographic imaging of carbon based samples have been problematic primarily due to the low secondary electron-I yield from specimens of low atomic mass. Both cold cathode and Schottky field emission (SFE) in-lens SEMs produce small beam diameters (5-10 Å) and achieve their highest resolution when operated at high (20-30 keV) accelerating voltages. The Topcon in-lens SFE-SEM/STEM has been in service at Emory U. for four years, and has generated quality images of carbon based materials and biological membranes. Enrichment of the SE-I signal from hydrocarbon based specimens was achieved by the application of a 1 run thick, fine grain Cr film and provided images of 1-2 nm particulate features without decoration or enlargement. Specimen beam interaction and the resultant particle contrast in a high magnification analog image recording was compared for graphitic carbon, diamond, and chromium coated polyvinylstyrene and fenestrated endothelial cell membranes (FECM).Chemical vapor deposition (CVD) was used to deposit various forms of carbon on Si (111) wafers.
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Ashby, Lynn S., and Timothy C. Ryken. "Management of malignant glioma: steady progress with multimodal approaches." Neurosurgical Focus 20, no. 4 (2006): E3. http://dx.doi.org/10.3171/foc.2006.20.4.3.
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✓Despite recent successes in the treatment of cancer with multidisciplinary multimodal treatment approaches, the duration of survival for patients with malignant glioma remains limited. Malignant gliomas represent a class of infiltrative, aggressive neoplasms that are generally resistant to combination therapies. The basic approach to treatment has involved a combination of surgery and radiotherapy. The use of chemotherapy has been met with skepticism because of its limited efficacy and the significant side effects demonstrated in clinical trials. Nevertheless, based on findings in randomized trials of new agents, it has been suggested that further evaluation of the role of chemotherapy is warranted. Temozolomide and Gliadel (carmustine wafers) are generally well tolerated due to their limited systemic toxicity. These agents appear particularly well suited for incorporation into multimodal treatment strategies. Proposed investigations and ongoing clinical trials will be conducted to assess the use of these agents in novel combination therapies. Future treatment strategies may include a wide variety of biological response modifiers, but will need to continue to address local control with surgery, radiation, and adjuvant chemotherapy.
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Trucillo, Paolo, and Ernesto Di Maio. "Classification and Production of Polymeric Foams among the Systems for Wound Treatment." Polymers 13, no. 10 (2021): 1608. http://dx.doi.org/10.3390/polym13101608.
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This work represents an overview on types of wounds according to their definition, classification and dressing treatments. Natural and synthetic polymeric wound dressings types have been analyzed, providing a historical overview, from ancient to modern times. Currently, there is a wide choice of materials for the treatment of wounds, such as hydrocolloids, polyurethane and alginate patches, wafers, hydrogels and semi-permeable film dressings. These systems are often loaded with drugs such as antibiotics for the simultaneous delivery of drugs to prevent or cure infections caused by the exposition of blood vessel to open air. Among the presented techniques, a focus on foams has been provided, describing the most diffused branded products and their chemical, physical, biological and mechanical properties. Conventional and high-pressure methods for the production of foams for wound dressing are also analyzed in this work, with a proposed comparison in terms of process steps, efficiency and removal of solvent residue. Case studies, in vivo tests and models have been reported to identify the real applications of the produced foams.
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Fiorentino, Giuseppe, Ben Jones, Sophie Roth, et al. "Silicon-Quartz Microcapillary Opto-Fluidic Platform Obtained by CMOS-Compatible Die to Wafer 200 mm Dual Bonding Process." Proceedings 2, no. 13 (2018): 1018. http://dx.doi.org/10.3390/proceedings2131018.
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A composite, capillary-driven microfluidic system suitable for transmitted light microscopy of cells (e.g., red and white human blood cells) is fabricated and demonstrated. The microfluidic system consists of a microchannels network fabricated in a photo-patternable adhesive polymer on a quartz substrate, which, by means of adhesive bonding, is then connected to a silicon microfluidic die (for processing of the biological sample) and quartz die (to form the imaging chamber). The entire bonding process makes use of a very low temperature budget (200 °C). In this demonstrator, the silicon die consists of microfluidic channels with transition structures to allow conveyance of fluid utilizing capillary forces from the polymer channels to the silicon channels and back to the polymer channels. Compared to existing devices, this fully integrated platform combines on the same substrate silicon microfluidic capabilities with optical system analysis, representing a portable and versatile lab-on-chip device.
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Al-Kattan, Ahmed, Lamiaa M. A. Ali, Morgane Daurat, Elodie Mattana, and Magali Gary-Bobo. "Biological Assessment of Laser-Synthesized Silicon Nanoparticles Effect in Two-Photon Photodynamic Therapy on Breast Cancer MCF-7 Cells." Nanomaterials 10, no. 8 (2020): 1462. http://dx.doi.org/10.3390/nano10081462.
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Driven by their distinctive physiological activities, biological properties and unique theranostic modalities, silicon nanoparticles (SiNPs) are one of the promising materials for the development of novel multifunctional nanoplatforms for biomedical applications. In this work, we assessed the possibility to use laser-synthesized Si NPs as photosensitizers in two-photon excited photodynamic therapy (TPE-PDT) modality. Herein, we used an easy strategy to synthesize ultraclean and monodispersed SiNPs using laser ablation and fragmentation sequences of silicon wafer in aqueous solution, which prevent any specific purification step. Structural analysis revealed the spherical shape of the nanoparticles with a narrow size distribution centered at the mean size diameter of 62 nm ± 0.42 nm, while the negative surface charge of −40 ± 0.3 mV ensured a great stability without sedimentation over a long period of time. In vitro studies on human cancer cell lines (breast and liver) and healthy cells revealed their low cytotoxicity without any light stimulus and their therapeutic potential under TPE-PDT mode at 900 nm with a promising cell death of 45% in case of MCF-7 breast cancer cells, as a consequence of intracellular reactive oxygen species release. Their luminescence emission inside the cells was clearly observed at UV-Vis region. Compared to Si nanoparticles synthesized via chemical routes, which are often linked to additional modules with photochemical and photobiological properties to boost photodynamic effect, laser-synthesized SiNPs exhibit promising intrinsic therapeutic and imaging properties to develop advanced strategy in nanomedicine field.
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Weis, Robert P., Jean-Luc Montchamp, Jeffery L. Coffer, Darlene Gamal Attiah, and Tejal A. Desai. "Calcified Nanostructured Silicon Wafer Surfaces for Biosensing: Effects of Surface Modification on Bioactivity." Disease Markers 18, no. 4 (2002): 159–65. http://dx.doi.org/10.1155/2002/727014.
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The growth of known biologically-relevant mineral phases on semiconducting surfaces is one strategy to explicitly induce bioactivity in such materials, either for sensing or drug delivery applications. In this work, we describe the use of a spark ablation process to fabricate deliberate patterns of Ca10(PO4)6(OH)2on crystalline Si (calcified nanoporous silicon). These patterns have been principally characterized by scanning electron microscopy in conjunction with elemental characterization by energy dispersive x-ray analysis. This is followed by a detailed comparison of the effects of fibroblast adhesion and proliferation onto calcified nanoporous Si, calcified nanoporous Si derivatized with alendronate, as well as control samples of an identical surface area containing porous SiO2. Fibroblast adhesion and proliferation assays demonstrate that a higher density of cells grow on the Ca3(PO4)2/porous Si/ SiO2structures relative to the alendronate-modified surfaces and porous Si/SiOM2samples.
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Martinson, Mercedes, Nazanin Samadi, Bassey Bassey, Ariel Gomez, and Dean Chapman. "Phase-preserving beam expander for biomedical X-ray imaging." Journal of Synchrotron Radiation 22, no. 3 (2015): 801–6. http://dx.doi.org/10.1107/s1600577515004695.
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The BioMedical Imaging and Therapy beamlines at the Canadian Light Source are used by many researchers to capture phase-based imaging data. These experiments have so far been limited by the small vertical beam size, requiring vertical scanning of biological samples in order to image their full vertical extent. Previous work has been carried out to develop a bent Laue beam-expanding monochromator for use at these beamlines. However, the first attempts exhibited significant distortion in the diffraction plane, increasing the beam divergence and eliminating the usefulness of the monochromator for phase-related imaging techniques. Recent work has been carried out to more carefully match the polychromatic and geometric focal lengths in a so-called `magic condition' that preserves the divergence of the beam and enables full-field phase-based imaging techniques. The new experimental parameters, namely asymmetry and Bragg angles, were evaluated by analysing knife-edge and in-line phase images to determine the effect on beam divergence in both vertical and horizontal directions, using the flat Bragg double-crystal monochromator at the beamline as a baseline. The results show that by using the magic condition, the difference between the two monochromator types is less than 10% in the diffraction plane. Phase fringes visible in test images of a biological sample demonstrate that this difference is small enough to enable in-line phase imaging, despite operating at a sub-optimal energy for the wafer and asymmetry angle that was used.
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Wright, Gus A., Lino Costa, Alexander Terekhov, Dawit Jowhar, William Hofmeister, and Christopher Janetopoulos. "On-Chip Open Microfluidic Devices for Chemotaxis Studies." Microscopy and Microanalysis 18, no. 4 (2012): 816–28. http://dx.doi.org/10.1017/s1431927612000475.
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AbstractMicrofluidic devices can provide unique control over both the chemoattractant gradient and the migration environment of the cells. Our work incorporates laser-machined micro and nanofluidic channels into bulk fused silica and cover slip-sized silica wafers. We have designed “open” chemotaxis devices that produce passive chemoattractant gradients without an external micropipette system. Since the migration area is unobstructed, cells can be easily loaded and strategically placed into the devices with a standard micropipette. The reusable monolithic glass devices have integral ports that can generate multiple gradients in a single experiment. We also used cover slip microfluidics for chemotaxis assays. Passive gradients elicited from these cover slips could be readily adapted for high throughput chemotaxis assays. We have also demonstrated for the first time that cells can be recruited into cover slip ports eliciting passive chemoattractant gradients. This proves, in principle, that intravital cover slip configurations could deliver controlled amounts of drugs, chemicals, or pathogens as well as recruit cells for proteomic or histological analysis in living animals while under microscopic observation. Intravital cover slip fluidics will create a new paradigm for in vivo observation of biological processes.
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Morand, Gabriel, Pascale Chevallier, Cédric Guyon, Michael Tatoulian, and Diego Mantovani. "In-Situ One-Step Direct Loading of Agents in Poly(acrylic acid) Coating Deposited by Aerosol-Assisted Open-Air Plasma." Polymers 13, no. 12 (2021): 1931. http://dx.doi.org/10.3390/polym13121931.
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In biomaterials and biotechnology, coatings loaded with bioactive agents are used to trigger biological responses by acting as drug release platforms and modulating surface properties. In this work, direct deposition of poly(acrylic acid) coatings containing various agents, such as dyes, fluorescent molecules, was achieved by aerosol-assisted open-air plasma. Using an original precursors injection strategy, an acrylic acid aerosol was loaded with an aqueous aerosol and deposited on silicon wafers. Results clearly showed that agents dissolved in the aqueous aerosol were successfully entrapped in the final coating. The effect of aerosols concentration, flow rate, and treatment time, on the coating morphology and the amount of entrapped agents, was also investigated. It was demonstrated that this process has the potential to entrap a tunable amount of any sensible water-soluble agent without altering its activity. To the best of our knowledge, this is the first time that the loading of an aqueous aerosol in coatings deposited by plasma from a liquid aerosol precursor is reported. This innovative approach complements plasma deposition of coatings loaded with bioactive agents from aqueous aerosols with the use of non-volatile liquid precursors.
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Park, Jin Hoo, Yong-Bin Lee, Sang Yoon Kim, Hyung Jun Kim, Young-Soo Jung, and Hwi-Dong Jung. "Accuracy of modified CAD/CAM generated wafer for orthognathic surgery." PLOS ONE 14, no. 5 (2019): e0216945. http://dx.doi.org/10.1371/journal.pone.0216945.
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Moghaddam, Maziar Sedighi, Golrokh Heydari, Mikko Tuominen, et al. "Hydrophobisation of wood surfaces by combining liquid flame spray (LFS) and plasma treatment: dynamic wetting properties." Holzforschung 70, no. 6 (2016): 527–37. http://dx.doi.org/10.1515/hf-2015-0148.
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Abstract The hydrophilic nature of wood surfaces is a major cause for water uptake and subsequent biological degradation and dimensional changes. In the present paper, a thin transparent superhydrophobic layer on pine veneer surfaces has been created for controlling surface wettability and water repellency. This effect was achieved by means of the liquid flame spray (LFS) technique, in the course of which the nanoparticulate titanium dioxide (TiO2) was brought to the surface, followed by plasma polymerisation. Plasma polymerised perfluorohexane (PFH) or hexamethyldisiloxane (HMDSO) were then deposited onto the LFS-treated wood surfaces. The same treatment systems were applied to silicon wafers so as to have well-defined reference surfaces. The dynamic wettability was studied by the multicycle Wilhelmy plate (mWP) method, resulting in advancing and receding contact angles as well as sorption behavior of the samples during repeated wetting cycles in water. Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were employed to characterise the topography and surface chemical compositions and to elucidate the question how the morphology of the nanoparticles and plasma affect the wetting behavior. A multi-scale roughness (micro-nano roughness) was found and this enhanced the forced wetting durability via a superhydrophobic effect on the surface, which was stable even after repeated wetting cycles. The hydrophobic effect of this approach was higher compared to that of plasma modified surfaces with their micro-scale modification.
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Elhami Nik, Farzad, Isabelle Matthiesen, Anna Herland, and Thomas Winkler. "Low-Cost PVD Shadow Masks with Submillimeter Resolution from Laser-Cut Paper." Micromachines 11, no. 7 (2020): 676. http://dx.doi.org/10.3390/mi11070676.
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We characterize an affordable method of producing stencils for submillimeter physical vapor deposition (PVD) by using paper and a benchtop laser cutter. Patterning electrodes or similar features on top of organic or biological substrates is generally not possible using standard photolithography. Shadow masks, traditionally made of silicon-based membranes, circumvent the need for aggressive solvents but suffer from high costs. Here, we evaluate shadow masks fabricated by CO2 laser processing from quantitative filter papers. Such papers are stiff and dimensionally stable, resilient in handling, and cut without melting or redeposition. Using two exemplary interdigitated electrode designs, we quantify the line resolution achievable with both high-quality and standard lenses, as well as the positional accuracy across multiple length scales. Additionally, we assess the gap between such laser-cut paper masks and a substrate, and quantify feature reproduction onto polycarbonate membranes. We find that ~100 µm line widths are achievable independent of lens type and that average positional accuracy is better than ±100 µm at 4”-wafer scale. Although this falls well short of the micron-size features achievable with typical shadow masks, resolution in the tenths to tens of millimeters is entirely sufficient for applications from contact pads to electrochemical cells, allowing new functionalities on fragile materials.
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Shome, Saikat Kumar, Mangal Prakash, Sourav Pradhan, and Arpita Mukherjee. "On Synergistic Integration of Adaptive Dithering Based Internal Model Control for Hysteresis Compensation in Piezoactuated Nanopositioner." Mathematical Problems in Engineering 2015 (2015): 1–19. http://dx.doi.org/10.1155/2015/365141.
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Piezoelectric-stack actuated platforms are very popular in the parlance of nanopositioning with myriad applications like micro/nanofactory, atomic force microscopy, scanning probe microscopy, wafer design, biological cell manipulation, and so forth. Motivated by the necessity to improve trajectory tracking in such applications, this paper addresses the problem of rate dependent hysteretic nonlinearity in piezoelectric actuators (PEA). The classical second order Dahl model for hysteresis encapsulation is introduced first, followed by the identification of parameters through particle swarm optimization. A novel inversion based feedforward mechanism in combination with a feedback compensator is proposed to achieve high-precision tracking wherein the paradoxical concept of noise as a performance enhancer is introduced in the realm of PZAs. Having observed that dither induced stochastic resonance in the presence of periodic forcing reduces tracking error, dither capability is further explored in conjunction with a novel output harmonics based adaptive control scheme. The proposed adaptive controller is then augmented with an internal model control based approach to impart robustness against parametric variations and external disturbances. The proposed control law has been employed to track multifrequency signals with consistent compensation of rate dependent hysteresis of the PEA. The results indicate a greatly improved positioning accuracy along with considerable robustness achieved with the proposed integrated approach even for dual axis tracking applications.
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Feld, Geoffrey K., Michael Heymann, W. Henry Benner, et al. "Low-Zpolymer sample supports for fixed-target serial femtosecond X-ray crystallography." Journal of Applied Crystallography 48, no. 4 (2015): 1072–79. http://dx.doi.org/10.1107/s1600576715010493.
Full textAbstract:
X-ray free-electron lasers (XFELs) offer a new avenue to the structural probing of complex materials, including biomolecules. Delivery of precious sample to the XFEL beam is a key consideration, as the sample of interest must be serially replaced after each destructive pulse. The fixed-target approach to sample delivery involves depositing samples on a thin-film support and subsequent serial introductionviaa translating stage. Some classes of biological materials, including two-dimensional protein crystals, must be introduced on fixed-target supports, as they require a flat surface to prevent sample wrinkling. A series of wafer and transmission electron microscopy (TEM)-style grid supports constructed of low-Zplastic have been custom-designed and produced. Aluminium TEM grid holders were engineered, capable of delivering up to 20 different conventional or plastic TEM grids using fixed-target stages available at the Linac Coherent Light Source (LCLS). As proof-of-principle, X-ray diffraction has been demonstrated from two-dimensional crystals of bacteriorhodopsin and three-dimensional crystals of anthrax toxin protective antigen mounted on these supports at the LCLS. The benefits and limitations of these low-Zfixed-target supports are discussed; it is the authors' belief that they represent a viable and efficient alternative to previously reported fixed-target supports for conducting diffraction studies with XFELs.
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Odzaev, V. B., A. N. Pyatlitski, V. A. Pilipenko, et al. "The influence of uncontrolled technological impurities on the temperature dependence of the gain coefficient of a bipolar n-p-n-transistor." Proceedings of the National Academy of Sciences of Belarus. Physics and Mathematics Series 57, no. 2 (2021): 232–41. http://dx.doi.org/10.29235/1561-2430-2021-57-2-232-241.
Full textAbstract:
Herein, the temperature dependences of the static current gain (β) of bipolar n-p-n-transistors, formed by similar process flows (series A and B), in the temperature range 20–125 °С was investigated. The content of uncontrolled technological impurities in the A series devices was below the detection limit by the TXRF method (for Fe < 4.0 · 109 at/cm2). In series B devices, the entire surface of the wafers was covered with a layer of Fe with an average concentration of 3.4 ∙ 1011 at/cm2; Cl, K, Ca, Ti, Cr, Cu, Zn spots were also observed. It was found that in B series devices at an average collector current level (1.0 ∙ 10–6 < Ic <1.0 ∙ 10–3 A) the static current gain was greater than the corresponding value in A series devices. This was due to the higher efficiency of the emitter due to the high concentration of the main dopant. This circumstance also determined a stronger temperature dependence of β in series B devices due to a significant contribution to its value from the temperature change in the silicon band gap. At Ic < 1.0 ∙ 10–6 A β for B series devices became significantly less than the corresponding values for A series devices and practically ceases to depend on temperature. In series B devices, the recombination-generation current prevailed over the useful diffusion current of minority charge carriers in the base due to the presence of a high concentration of uncontrolled technological impurities. For A series devices at Ic < 10–6 A, the temperature dependence of β practically did not differ from the analogous dependence for the average injection level.
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Buriak, Jillian M. "High surface area silicon materials: fundamentals and new technology." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 364, no. 1838 (2005): 217–25. http://dx.doi.org/10.1098/rsta.2005.1681.
Full textAbstract:
Crystalline silicon forms the basis of just about all computing technologies on the planet, in the form of microelectronics. An enormous amount of research infrastructure and knowledge has been developed over the past half-century to construct complex functional microelectronic structures in silicon. As a result, it is highly probable that silicon will remain central to computing and related technologies as a platform for integration of, for instance, molecular electronics, sensing elements and micro- and nanoelectromechanical systems. Porous nanocrystalline silicon is a fascinating variant of the same single crystal silicon wafers used to make computer chips. Its synthesis, a straightforward electrochemical, chemical or photochemical etch, is compatible with existing silicon-based fabrication techniques. Porous silicon literally adds an entirely new dimension to the realm of silicon-based technologies as it has a complex, three-dimensional architecture made up of silicon nanoparticles, nanowires, and channel structures. The intrinsic material is photoluminescent at room temperature in the visible region due to quantum confinement effects, and thus provides an optical element to electronic applications. Our group has been developing new organic surface reactions on porous and nanocrystalline silicon to tailor it for a myriad of applications, including molecular electronics and sensing. Integration of organic and biological molecules with porous silicon is critical to harness the properties of this material. The construction and use of complex, hierarchical molecular synthetic strategies on porous silicon will be described.
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Fan, Tengjiao, Guohui Sun, Xiaodong Sun, Lijiao Zhao, Rugang Zhong, and Yongzhen Peng. "Tumor Energy Metabolism and Potential of 3-Bromopyruvate as an Inhibitor of Aerobic Glycolysis: Implications in Tumor Treatment." Cancers 11, no. 3 (2019): 317. http://dx.doi.org/10.3390/cancers11030317.
Full textAbstract:
Tumor formation and growth depend on various biological metabolism processes that are distinctly different with normal tissues. Abnormal energy metabolism is one of the typical characteristics of tumors. It has been proven that most tumor cells highly rely on aerobic glycolysis to obtain energy rather than mitochondrial oxidative phosphorylation (OXPHOS) even in the presence of oxygen, a phenomenon called “Warburg effect”. Thus, inhibition of aerobic glycolysis becomes an attractive strategy to specifically kill tumor cells, while normal cells remain unaffected. In recent years, a small molecule alkylating agent, 3-bromopyruvate (3-BrPA), being an effective glycolytic inhibitor, has shown great potential as a promising antitumor drug. Not only it targets glycolysis process, but also inhibits mitochondrial OXPHOS in tumor cells. Excellent antitumor effects of 3-BrPA were observed in cultured cells and tumor-bearing animal models. In this review, we described the energy metabolic pathways of tumor cells, mechanism of action and cellular targets of 3-BrPA, antitumor effects, and the underlying mechanism of 3-BrPA alone or in combination with other antitumor drugs (e.g., cisplatin, doxorubicin, daunorubicin, 5-fluorouracil, etc.) in vitro and in vivo. In addition, few human case studies of 3-BrPA were also involved. Finally, the novel chemotherapeutic strategies of 3-BrPA, including wafer, liposomal nanoparticle, aerosol, and conjugate formulations, were also discussed for future clinical application.