127 research outputs found

    APPLICATIONS OF UV-LIGA AND GRAYSCALE LITHOGRAPHY FOR DISPLAY TECHNOLOGIES

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    In the article MEMS technologies for display production and application presented. UV-LIGA and greyscale lithography based on SU-8 resist approaches were shown. Methods, technologies and structures of heterogeneous materials with soft magnetic properties, pros and cons are discussed. Unique specific parameters of soft magnetic composite material were achieved: magnetic induction of saturation – 2,1 Т, working frequency range – up to 1 MHz, permeability – up to 3000, total loss – 8 W/kg, Curie temperature – above 800 ºС. Electroplating allows deposition of soft magnetic alloys on the conductive substrate. Metals like Fe, Ni, Co with additives like B, P were used to get the best soft magnetic properties. Special codeposition process was developed to allow insertion of soft magnetic composite powder filaments into soft magnetic matrix formed during. It allows developing magnetic micromotors for display production. Simulation of the hybrid step micromotors was carried out in Ansys Maxwell 19. It was demonstrated that it is possible to get 10 mN m tourqe under 25 μm rotor-stator air gap. Only presented microtechnologies can provide such accuracy of the mciromotors elements. As for greyscale photolithography, special grey mask were developed and it was demonstrated the possibility to produce controllable real 3D relief on the SU-8 photoresist. Thus, microtechnologies should be integrated into display technology to provide cost effective production and advanced properties of final products.In the article MEMS technologies for display production and application presented. UV-LIGA and greyscale lithography based on SU-8 resist approaches were shown. Methods, technologies and structures of heterogeneous materials with soft magnetic properties, pros and cons are discussed. Unique specific parameters of soft magnetic composite material were achieved: magnetic induction of saturation – 2,1 Т, working frequency range – up to 1 MHz, permeability – up to 3000, total loss – 8 W/kg, Curie temperature – above 800 ºС. Electroplating allows deposition of soft magnetic alloys on the conductive substrate. Metals like Fe, Ni, Co with additives like B, P were used to get the best soft magnetic properties. Special codeposition process was developed to allow insertion of soft magnetic composite powder filaments into soft magnetic matrix formed during. It allows developing magnetic micromotors for display production. Simulation of the hybrid step micromotors was carried out in Ansys Maxwell 19. It was demonstrated that it is possible to get 10 mN m tourqe under 25 μm rotor-stator air gap. Only presented microtechnologies can provide such accuracy of the mciromotors elements. As for greyscale photolithography, special grey mask were developed and it was demonstrated the possibility to produce controllable real 3D relief on the SU-8 photoresist. Thus, microtechnologies should be integrated into display technology to provide cost effective production and advanced properties of final products

    Helical Chirality: a Link between Local Interactions and Global Topology in DNA

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    DNA supercoiling plays a major role in many cellular functions. The global DNA conformation is however intimately linked to local DNA-DNA interactions influencing both the physical properties and the biological functions of the supercoiled molecule. Juxtaposition of DNA double helices in ubiquitous crossover arrangements participates in multiple functions such as recombination, gene regulation and DNA packaging. However, little is currently known about how the structure and stability of direct DNA-DNA interactions influence the topological state of DNA. Here, a crystallographic analysis shows that due to the intrinsic helical chirality of DNA, crossovers of opposite handedness exhibit markedly different geometries. While right-handed crossovers are self-fitted by sequence-specific groove-backbone interaction and bridging Mg2+ sites, left-handed crossovers are juxtaposed by groove-groove interaction. Our previous calculations have shown that the different geometries result in differential stabilisation in solution, in the presence of divalent cations. The present study reveals that the various topological states of the cell are associated with different inter-segmental interactions. While the unstable left-handed crossovers are exclusively formed in negatively supercoiled DNA, stable right-handed crossovers constitute the local signature of an unusual topological state in the cell, such as the positively supercoiled or relaxed DNA. These findings not only provide a simple mechanism for locally sensing the DNA topology but also lead to the prediction that, due to their different tertiary intra-molecular interactions, supercoiled molecules of opposite signs must display markedly different physical properties. Sticky inter-segmental interactions in positively supercoiled or relaxed DNA are expected to greatly slow down the slithering dynamics of DNA. We therefore suggest that the intrinsic helical chirality of DNA may have oriented the early evolutionary choices for DNA topology

    Development of anti-foulant ultraviolet-assisted polyvinyl alcohol layer on the polysulfone-based nanohybrid membrane for industrial rubber wastewater decontamination

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    Introduction: Membrane fouling has been reported to be one of the bottlenecks of membrane technologies for wastewater treatment. To mitigate its negative impacts, we fabricated polysulfone membrane (PSf) composites made of silica (SiO2) and graphene oxide (GO) nanoparticles that modified with ultraviolet (UV)-assisted polyvinyl alcohol layer on the membrane surface.Methods: The membrane composite was synthesized using non-solvent induced phase separation (NIPS) method. The membrane was further treated by UV irradiation and cross-linked with PVA coating to cope with the fouling problem. The modified membrane was applied for industrial rubber wastewater decontamination.Results: The UV irradiation and cross-linked PVA coating to the PSf/GO-SiO2 membrane improved the pseudo-steady state permeate flux by 60.15% from 20.05 to 50.32 L/m2hr and maintained the permeate flux up to 82.33%. About 85% of total dissolved solids (TDS), 81% of chemical oxygen demand (COD), and 84% of ammonia compound (NH3) with initial concentrations of 335.76, 242.55, 175.19 mg/L, respectively, could be removed after 8 h of membrane treatment. The modified membrane also exhibited an excellent flux recovery ratio of up to 83%.Discussion: The modified membrane changed the fouling mechanism from pore blockage to cake filtration, which signifies the capability of the membrane to tackle severe fouling tendency. The cross-linked UV/PVA coating reduced fouling formation by reducing the adsorptive interactions between the foulant molecules and the membrane surface by enhancing membrane surface hydrophilicity. This implies that incorporating GO/SiO2 nanoparticles with UV irradiation and PVA coating substantially enhanced the physicochemical properties of the PSf membrane

    Alteration of Relative Rates of Biodegradation and Regeneration of Cervical Spine Cartilage through the Restoration of Arterial Blood Flow Access to Rhomboid Fossa: A Hypothesis

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    We found the logical way to prove the existence of the mechanism that maintains the rates of biodegradation and regeneration of cervical spine cartilage. We demonstrate, that after we restore access to arterial blood flow through cervical vertebral arteries to rhomboid fossa it causes the prevalence of regeneration over biodegradation. This is in the frames of consideration of the human body as a dissipative structure. Then the recovery of the body should be considered as a reduction of the relative rates of decay below the regeneration ones. Then the recovery of cervical spine cartilage through redirecting of inner dissipative flow depends on the information about oxygen availability that is provided from oxygen detectors in the rhomboid fossa to the cerebellum. Our proposed approach explains already collected data, which satisfies all the scientific requirements. This allows us to draw conclusions that permit reconsidering the way of dealing with multiple chronic diseases

    Discovery and validation of small-molecule heat-shock protein 90 inhibitors through multimodality molecular imaging in living subjects

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    Up-regulation of the folding machinery of the heat-shock protein 90 (Hsp90) chaperone protein is crucial for cancer progression. The two Hsp90 isoforms (α and β) play different roles in response to chemotherapy. To identify isoform-selective inhibitors of Hsp90(α/β)/cochaperone p23 interactions, we developed a dual-luciferase (Renilla and Firefly) reporter system for high-throughput screening (HTS) and monitoring the efficacy of Hsp90 inhibitors in cell culture and live mice. HTS of a 30,176 small-molecule chemical library in cell culture identified a compound, N-(5-methylisoxazol-3-yl)-2-[4-(thiophen-2-yl)-6-(trifluoromethyl)pyrimidin-2-ylthio]acetamide (CP9), that binds to Hsp90(α/β) and displays characteristics of Hsp90 inhibitors, i.e., degradation of Hsp90 client proteins and inhibition of cell proliferation, glucose metabolism, and thymidine kinase activity, in multiple cancer cell lines. The efficacy of CP9 in disrupting Hsp90(α/β)/p23 interactions and cell proliferation in tumor xenografts was evaluated by non-invasive, repetitive Renilla luciferase and Firefly luciferase imaging, respectively. At 38 h posttreatment (80 mg/kg × 3, i.p.), CP9 led to selective disruption of Hsp90α/p23 as compared with Hsp90β/p23 interactions. Small-animal PET/CT in the same cohort of mice showed that CP9 treatment (43 h) led to a 40% decrease in 18F-fluorodeoxyglucose uptake in tumors relative to carrier control-treated mice. However, CP9 did not lead to significant degradation of Hsp90 client proteins in tumors. We performed a structural activity relationship study with 62 analogs of CP9 and identified A17 as the lead compound that outperformed CP9 in inhibiting Hsp90(α/β)/p23 interactions in cell culture. Our efforts demonstrated the power of coupling of HTS with multimodality molecular imaging and led to identification of Hsp90 inhibitors

    Applications of UV-LIGA and grayscale lithography for display technologies

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    In the article MEMS technologies for display production and application presented. UV-LIGA and greyscale lithography based on SU-8 resist approaches were shown. Methods, technologies and structures of heterogeneous materials with soft magnetic properties, pros and cons are discussed. Unique specific parameters of soft magnetic composite material were achieved: magnetic induction of saturation – 2,1 Т, working frequency range – up to 1 MHz, permeability – up to 3000, total loss – 8 W/kg, Curie temperature – above 800 єС. Electroplating allows deposition of soft magnetic alloys on the conductive substrate. Metals like Fe, Ni, Co with additives like B, P were used to get the best soft magnetic properties. Special codeposition process was developed to allow insertion of soft magnetic composite powder filaments into soft magnetic matrix formed during. It allows developing magnetic micromotors for display production. Simulation of the hybrid step micromotors was carried out in Ansys Maxwell 19. It was demonstrated that it is possible to get 10 mN m tourqe under 25 μm rotor-stator air gap. Only presented microtechnologies can provide such accuracy of the mciromotors elements. As for greyscale photolithography, special grey mask were developed and it was demonstrated the possibility to produce controllable real 3D relief on the SU-8 photoresist. Thus, microtechnologies should be integrated into display technology to provide cost effective production and advanced properties of final products

    Structural diversity of supercoiled DNA

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    By regulating access to the genetic code, DNA supercoiling strongly affects DNA metabolism. Despite its importance, however, much about supercoiled DNA (positively supercoiled DNA, in particular) remains unknown. Here we use electron cryo-tomography together with biochemical analyses to investigate structures of individual purified DNA min icircle topoisomers with defined degrees of supercoiling. Our results reveal that each topoisomer, negative or positive, adopts a unique and surprisingly wide distribution of three-dimensional conformations. Moreover, we uncover striking differences in how the topoisomers handle torsional stress. As negative supercoiling increases, bases are increasingly exposed. Beyond a sharp supercoiling threshold, we also detect exposed bases in positively supercoiled DNA. Molecular dynamics simulations independently confirm the conformational heterogeneity and provide atomistic insight into the flexibility of supercoiled DNA. Our integrated approach reveals the three-dimensional structures of DNA that are essential for its function

    Sticky DNA, a Long GAA·GAA·TTC Triplex That Is Formed Intramolecularly, in the Sequence of Intron 1 of the Frataxin Gene

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    Friedreich's ataxia is caused by the massive expansion of GAA.TTC repeats in intron 1 of the frataxin (X25) gene. Our prior investigations showed that long GAA.TTC repeats formed very stable triplex structures which caused two repeat tracts to adhere to each other (sticky DNA). This process was dependent on negative supercoiling and the presence of divalent metal ions. Herein, we have investigated the formation of sticky DNA from plasmid monomers and dimers; sticky DNA is formed only when two tracts of sufficiently long (GAA.TTC)(n) (n = 59-270) are present in a single plasmid DNA and are in the direct repeat orientation. If the inserts are in the indirect (inverted) repeat orientation, no sticky DNA was observed. Furthermore, kinetic studies support the intramolecular nature of sticky DNA formation. Electron microscopy investigations also provide strong data for sticky DNA as a single long triplex. Hence, these results give new insights into our understanding of the capacity of sticky DNA to inhibit transcription and thereby reduce the level of frataxin protein as related to the etiology of Friedreich's ataxia

    Электрические свойства композитов на основе порошков железа, капсулированных оксидным покрытием

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    The electrical characteristics of composite materials based on iron powders ASC 100.29 (Sweden) were investigated. The surface of powders is encapsulated by an insulating ferrite coating. The conductivity and the thermopower were studied, the cores were made by the pressing method, and then the samples were cut from the cores. The results show that the decrease in the electrical resistance with increasing temperature is due to a change in the contact between the grains in the sample. A change in the boundaries between grains (or domains) creates the conditions for formation of a new magnon, which affects the thermopower coefficient value. The research results can be used in the synthesis of composites with specified electromagnetic characteristics for practical applications.Исследованы электрические характеристики композиционных материалов на основе порошков железа ASC 100.29 (Швеция). Поверхность порошков капсулирована изоляционным ферритным покрытием. Для проведения исследований удельной электропроводности и термоЭДС методом прессования изготавливались сердечники, из которых вырезались образцы. Результаты показывают, что уменьшение величины электросопротивления с ростом температуры обусловлено изменением контакта между зернами в образце. Изменение границ между зернами (или доменами) создает условия образования нового магнона, что оказывает влияние на величину коэффициента термоЭДС. Результаты исследований могут быть использованы при синтезе композитов с заданными электромагнитными характеристиками для практических применений

    Electromagnetic MEMS motors for display technologies

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    The fourth revolution of the industry is powered by a wide range breakthrough, new technology, innovative ideas and creative activities. All these things were naturally born, mostly, by the interdisciplinary science and technology. Soft magnetic composites are the bright example of the different technologies integration to get final commercial technologies to get the final products with enhanced properties. Micro displacement and micro positioning became a very important factor for new display technologies such as inkjet, 3D printing, nanoimprint. New generation of technologies allows increasing productivity and improving quality. MEMS micromotors are the core of such instruments for display production
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