Articles de revues : « Polymeric mask »

1

Canavese, G., S. L. Marasso, M. Quaglio, M. Cocuzza, C. Ricciardi et C. F. Pirri. « Polymeric mask protection for alternative KOH silicon wet etching ». Journal of Micromechanics and Microengineering 17, n^o 7 (15 juin 2007) : 1387–93. http://dx.doi.org/10.1088/0960-1317/17/7/022.

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Li, Xingzhou, et Yan Gong. « Design of Polymeric Nanofiber Gauze Mask to Prevent Inhaling PM2.5 Particles from Haze Pollution ». Journal of Chemistry 2015 (2015) : 1–5. http://dx.doi.org/10.1155/2015/460392.

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Recently, PM2.5 (particulate matter with diameter of 2.5 micron or less) has become a major health hazard from the polluted air in many cities in China. The regular gauze masks are used to prevent inhaling the PM2.5 fine particles; however, those masks are not able to filter out the PM2.5 because of the large porosity of the mask materials. Some well-prevented masks usually have poor breathability, which increases other health risks. In this study, a polysulfone based nanofiber for mask filtration material was synthesized by electrospinning. That nanofiber mask material was characterized by SEM, air permeability test, and PM2.5 trapping experiment. The results indicate that nanofiber mask material can efficiently filter out the PM2.5 particles and simultaneously preserve a good breathability. We attribute such improvement to the nanoscaled fibers, having the same porosity as that of regular gauze mask but with extremely reduced local interfiber space.

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Wibisono, Yusuf, Cut Rifda Fadila, Saiful Saiful et Muhammad Roil Bilad. « Facile Approaches of Polymeric Face Masks Reuse and Reinforcements for Micro-Aerosol Droplets and Viruses Filtration : A Review ». Polymers 12, n^o 11 (28 octobre 2020) : 2516. http://dx.doi.org/10.3390/polym12112516.

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Since the widespread of severe acute respiratory syndrome of coronavirus 2 (SARS-CoV-2) disease, the utilization of face masks has become omnipresent all over the world. Face masks are believed to contribute to an adequate protection against respiratory infections spread through micro-droplets among the infected person to non-infected others. However, due to the very high demands of face masks, especially the N95-type mask typically worn by medical workers, the public faces a shortage of face masks. Many papers have been published recently that focus on developing new and facile techniques to reuse and reinforce commercially available face masks. For instance, the N95 mask uses a polymer-based (membrane) filter inside, and the filter membrane can be replaced if needed. Another polymer sputtering technique by using a simple cotton candy machine could provide a cheap and robust solution for face mask fabrication. This review discuss the novel approaches of face mask reuse and reinforcement specifically by using membrane-based technology. Tuning the polymeric properties of face masks to enhance filterability and virus inactivity is crucial for future investigation.

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Jeon, Sangheon, Pyunghwa Han, Jeonghwa Jeong, Wan Sik Hwang et Suck Won Hong. « Highly Aligned Polymeric Nanowire Etch-Mask Lithography Enabling the Integration of Graphene Nanoribbon Transistors ». Nanomaterials 11, n^o 1 (25 décembre 2020) : 33. http://dx.doi.org/10.3390/nano11010033.

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Graphene nanoribbons are a greatly intriguing form of nanomaterials owing to their unique properties that overcome the limitations associated with a zero bandgap of two-dimensional graphene at room temperature. Thus, the fabrication of graphene nanoribbons has garnered much attention for building high-performance field-effect transistors. Consequently, various methodologies reported previously have brought significant progress in the development of highly ordered graphene nanoribbons. Nonetheless, easy control in spatial arrangement and alignment of graphene nanoribbons on a large scale is still limited. In this study, we explored a facile, yet effective method for the fabrication of graphene nanoribbons by employing orientationally controlled electrospun polymeric nanowire etch-mask. We started with a thermal chemical vapor deposition process to prepare graphene monolayer, which was conveniently transferred onto a receiving substrate for electrospun polymer nanowires. The polymeric nanowires act as a robust etching barrier underlying graphene sheets to harvest arrays of the graphene nanoribbons. On varying the parametric control in the process, the size, morphology, and width of electrospun polymer nanowires were easily manipulated. Upon O2 plasma etching, highly aligned arrays of graphene nanoribbons were produced, and the sacrificial polymeric nanowires were completely removed. The graphene nanoribbons were used to implement field-effect transistors in a bottom-gated configuration. Such approaches could realistically yield a relatively improved current on–off ratio of ~30 higher than those associated with the usual micro-ribbon strategy, with the clear potential to realize reproducible high-performance devices.

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Kim, Jin Tae, et Choon-Gi Choi. « Absorber embedded x-ray mask for high aspect ratio polymeric optical components ». Journal of Micromechanics and Microengineering 15, n^o 3 (14 janvier 2005) : 615–19. http://dx.doi.org/10.1088/0960-1317/15/3/025.

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Foffa, Ilenia, Paola Losi, Paola Quaranta, Alice Cara, Tamer Al Kayal, Mario D’Acunto, Gianluca Presciuttini, Mauro Pistello et Giorgio Soldani. « A Copper nanoparticles-based polymeric spray coating : Nanoshield against Sars-Cov-2 ». Journal of Applied Biomaterials & ; Functional Materials 20 (janvier 2022) : 228080002210763. http://dx.doi.org/10.1177/22808000221076326.

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Face masks are an effective protection tool to prevent bacterial and viral transmission. However, commercial face masks contain filters made of materials that are not capable of inactivating either SARS-CoV-2. In this regard, we report the development of an antiviral coating of polyurethane and Copper nanoparticles on a face mask filter fabricated with a spray technology that is capable of inactivating more than 99% of SARS-CoV-2 particles in 30 min of contact.

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Dalvi-Malhotra, J., X. F. Zhong, C. Planje, G. Brand et K. Yess. « A spin-on photosensitive polymeric etch protection mask for anisotropic wet etching of silicon ». Journal of Micromechanics and Microengineering 18, n^o 2 (9 janvier 2008) : 025029. http://dx.doi.org/10.1088/0960-1317/18/2/025029.

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Baek, Jae Yun, Kyung Mook Kang, Hyeong Jun Kim, Ju Hyeon Kim, Ju Hwan Lee, Gilyong Shin, Jei Gyeong Jeon et al. « Manufacturing Process of Polymeric Microneedle Sensors for Mass Production ». Micromachines 12, n^o 11 (5 novembre 2021) : 1364. http://dx.doi.org/10.3390/mi12111364.

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In this work, we present a fabrication process for microneedle sensors made of polylactic acid (PLA), which can be utilized for the electrochemical detection of various biomarkers in interstitial fluid. Microneedles were fabricated by the thermal compression molding of PLA into a laser machined polytetrafluoroethylene (PTFE) mold. Sensor fabrication was completed by forming working, counter, and reference electrodes on each sensor surface by Au sputtering through a stencil mask, followed by laser dicing to separate individual sensors from the substrate. The devised series of processes was designed to be suitable for mass production, where multiple microneedle sensors can be produced at once on a 4-inch wafer. The operational stability of the fabricated sensors was confirmed by linear sweep voltammetry and cyclic voltammetry at the range of working potentials of various biochemical molecules in interstitial fluid.

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Fitri, Raissa, Hariyadi Dharmawan Syahputra, Nasri Nasri, Vera Estefania Kaban et Zulmai Rani. « Formulation of a biocellulose mask containing the essence of Aloe vera (L.) Burm.f combination with vitamin E as anti-aging ». ScienceRise : Pharmaceutical Science, n^o 6(40) (30 décembre 2022) : 36–42. http://dx.doi.org/10.15587/2519-4852.2022.268987.

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Most ageing processes are accelerated due to an increasing amount of endogenic stress from outdoor or indoor activity overload. The essence of aloe vera is formulated in the form of a biocellulose mask. It is one of the solutions to deliver essence within polymeric substances, obtained through the fermentation process with the help of Acetobacter xyllinum. The aim of this study is to enhance anti-ageing activity derived from Aloe vera (L) essence combined with vitamin E, thus in the form of a biocellulose mask that will prolong skin contact and reduce the main cotton sheet mask problem of deforestation, hence its eco-friendly benefit. Material and methods: Twelve volunteers around 25 to 45 years old are subjected to a biocellulose mask containing Aloe vera essence combined with vitamin E for at least 4 weeks to achieve a balanced skin criterion including wrinkles, spots, facial pores, and moisture. Aloe vera and vitamin E constituents within F0; F1, F2; F3, [0%, 0%]; [0%, 1%]; [5%, 0 %] and [5 %, 1 %] as per the following. Results: Results showed that bio-cellulose masks containing 5 % Aloe vera with 1 % of vitamin E essence in F3 provide a beneficial anti-ageing activity rather than other biocellulose mask preparations. Conclusion: Biocellulose mask through the fermentation process can improve skin conditions, the formula combined with the well-known activity of aloe vera as an exfoliating agent and antioxidant vitamin E, it can not only provide skin rejuvenation but also provide anti-ageing activity

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Lu, Wen-Chi, Ching-Yi Chen, Chia-Jung Cho, Manikandan Venkatesan, Wei-Hung Chiang, Yang-Yen Yu, Chen-Hung Lee, Rong-Ho Lee, Syang-Peng Rwei et Chi-Ching Kuo. « Antibacterial Activity and Protection Efficiency of Polyvinyl Butyral Nanofibrous Membrane Containing Thymol Prepared through Vertical Electrospinning ». Polymers 13, n^o 7 (1 avril 2021) : 1122. http://dx.doi.org/10.3390/polym13071122.

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Human safety, health management, and disease transmission prevention have become crucial tasks in the present COVID-19 pandemic situation. Masks are widely available and create a safer and disease transmission–free environment. This study presents a facile method of fabricating masks through electrospinning nontoxic polyvinyl butyral (PVB) polymeric matrix with the antibacterial component Thymol, a natural phenol monoterpene. Based on the results of Japanese Industrial Standards and American Association of Textile Chemists and Colorists methods, the maximum antibacterial value of the mask against Gram-positive and Gram-negative bacteria was 5.6 and 6.4, respectively. Moreover, vertical electrospinning was performed to prepare Thymol/PVB nanofiber masks, and the effects of parameters on the submicron particulate filtration efficiency (PFE), differential pressure, and bacterial filtration efficiency (BFE) were determined. Thorough optimization of the small-diameter nanofiber–based antibacterial mask led to denser accumulation and improved PFE and pressure difference; the mask was thus noted to meet the present pandemic requirements. The as-developed nanofibrous masks have the antibacterial activity suggested by the National Standard of the Republic of China (CNS 14774) for general medical masks. Their BFE reaches 99.4%, with a pressure difference of <5 mmH2O/cm2. The mask can safeguard human health and promote a healthy environment.

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Poulin, Jerome, et Raman Kashyap. « Novel tuneable on-fiber polymeric phase-mask for fiber and planar waveguide Bragg grating fabrication ». Optics Express 13, n^o 12 (2005) : 4414. http://dx.doi.org/10.1364/opex.13.004414.

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Rahim, Rosminazuin Ab, Badariah Bais, Burhanuddin Yeop Majlis et Gandi Sugandi. « ProTEK PSB coating as an alternative polymeric protection mask for KOH bulk etching of silicon ». Microsystem Technologies 19, n^o 6 (3 avril 2013) : 905–14. http://dx.doi.org/10.1007/s00542-013-1794-z.

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Volpe, Annalisa, Filippo Maria Conte Capodacqua, Valeria Garzarelli, Elisabetta Primiceri, Maria Serena Chiriacò, Caterina Gaudiuso, Francesco Ferrara et Antonio Ancona. « Femtosecond Laser Fabrication of Microporous Membranes for Biological Applications ». Micromachines 13, n^o 9 (23 août 2022) : 1371. http://dx.doi.org/10.3390/mi13091371.

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The possibility of fabricating micrometric pore size membranes is gaining great interest in many applications, from studying cell signaling, to filtration. Currently, many technologies are reported to fabricate such microsystems, the choice of which depends strictly on the substrate material and on the final application. Here, we demonstrate the capability with a single femtosecond laser source and experimental setup to fabricate micromembranes both on polymeric and multilayer metallic substrate, without the need for moulds, mask, and complex facilities. In particular, the flexibility of laser drilling was exploited to obtain microfilters with pore size of 8 and 18 µm in diameter, on metallic and polymeric substrate, respectively, and controlled distribution. For evaluating the possibility to use such laser-fabricated membranes into biological assay, their biocompatibility has been investigated. To this aim, as a proof of concept, we tested the two materials into viability tests. The culture of mammalian cells on these microfabricated membranes were studied showing their compatibility with cells.

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Lee, Hong-Ji, Che-Lun Hung, Chia-Hao Leng, Nan-Tzu Lian, Ling-Wu Young, Tahone Yang, Kuang-Chao Chen et Chih-Yuan Lu. « Etch Defect Characterization and Reduction in Hard-Mask-Based Al Interconnect Etching ». International Journal of Plasma Science and Engineering 2008 (23 septembre 2008) : 1–5. http://dx.doi.org/10.1155/2008/154035.

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This paper identifies the defect adders, for example, post hard-mask etch residue, post metal etch residue, and blocked etch metal island and investigates the removal characteristics of these defects within the oxide-masked Al etching process sequence. Post hard-mask etch residue containing C atom is related to the hardening of photoresist after the conventional post-RIE ashing at 275∘C. An in situ O2-based plasma ashing on RIE etcher was developed to prevent the photoresist hardening from the high-ashing temperature; followed wet stripping could successfully eliminate such hardened polymeric residue. Post metal etch residue was caused from the attack of the Al sidewall by Cl atoms, and too much CHF3 addition in the Al main etch step passivated the surface of Al resulting in poor capability to remove the Al-containing residue. The lower addition of CHF3 in the Al main etch step would benefit from the residue removal. One possibility of blocked etch metal island creating was due to the micromasking formed on the opening of TiN during the hard-mask patterning. We report that an additional TiN surface pretreatment with the Ar/CHF3/N2 plasmas could reduce the impact of the micromasking residues on blocked metal etch.

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Forouzmehr, Matin, Serges Zambou, Kimmo Lahtonen, Mari Honkanen, Rafi Md Nazmul Anam, Aleksi Ruhanen, Chakra Rokaya, Donald Lupo et Paul R. Berger. « Selective atomic layer deposition on flexible polymeric substrates employing a polyimide adhesive as a physical mask ». Journal of Vacuum Science & ; Technology A 39, n^o 1 (janvier 2021) : 012405. http://dx.doi.org/10.1116/6.0000566.

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Peinador, R. I., José I. Calvo et Roger Ben Aim. « Comparison of Capillary Flow Porometry (CFP) and Liquid Extrusion Porometry (LEP) Techniques for the Characterization of Porous and Face Mask Membranes ». Applied Sciences 10, n^o 16 (17 août 2020) : 5703. http://dx.doi.org/10.3390/app10165703.

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This work aims to study the characterization of several membrane filters by using capillary flow porometry (CFP) and liquid extrusion porometry (LEP) to obtain their pore size distributions (PSD) and mean pore diameters (davg). Three polymeric membranes of different materials namely, polyethylene (PET), cellulose nitrate (CN), and FM (face mask), and one inorganic (namely, alumina Al2O3) from ultrafiltration (UF)/microfiltration (MF) and particle separation were analyzed using a pressure constant fluid/liquid extrusion porometer, developed at institute de la filtration et techniques séparatives (IFTS). Several porosimetric fluids have been used to wet and penetrate into the porous/fiber structure. The results show the accuracy of the setup on characterizing membranes in the UF/MF range by CFP, with reasonable agreement with nominal data of the filters. Additionally, LEP extension of the equipment obtained good agreement with nominal data and the CFP results, while filters presenting a microstructure of highly interconnected pores (face mask) resulted in clear differences in terms of resulting PSD and average sizes when CFP and LEP results are compared.

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Beardslee, Luke A., Dimitrius A. Khaladj et Magnus Bergkvist. « Preliminary Investigation of a Sacrificial Process for Fabrication of Polymer Membranes with Sub-Micron Thickness ». MRS Proceedings 1621 (2014) : 113–18. http://dx.doi.org/10.1557/opl.2014.69.

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ABSTRACTHere we present a single mask sacrificial molding process that allows ultrathin 2-dimensional membranes to be fabricated using biocompatible polymeric materials. For initial investigations, polycaprolactone (PCL) was chosen as a model material. The process is capable of creating 250-500 nm thin, through-hole PCL membranes with various geometries, pore-sizes and spatial features approaching 2.5 micrometers using contact photolithography. The technique uses a mold created from two layers of lift-off resist (LOR). The upper layer is patterned, while the lower layer acts as a sacrificial release layer for the polymer membrane. For mold fabrication, photoresist on top of the layers of lift-off resist is patterned using conventional photolithography. During development the mask pattern is transferred onto the first LOR layer and the photoresist is removed using acetone, leaving behind a thin mold. The mold is filled with a solution of the desired polymer. Subsequently, both the patterned and lower LOR layers are dissolved by immersion in an alkaline solution. The membrane can be mounted onto support structures pre-release to facilitate handling.

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Dardano, Principia, Selene De Martino, Mario Battisti, Bruno Miranda, Ilaria Rea et Luca De Stefano. « One-Shot Fabrication of Polymeric Hollow Microneedles by Standard Photolithography ». Polymers 13, n^o 4 (9 février 2021) : 520. http://dx.doi.org/10.3390/polym13040520.

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Microneedles (MNs) are an emerging technology in pharmaceutics and biomedicine, and are ready to be commercialized in the world market. However, solid microneedles only allow small doses and time-limited administration rates. Moreover, some well-known and already approved drugs need to be re-formulated when supplied by MNs. Instead, hollow microneedles (HMNs) allow for rapid, painless self-administrable microinjection of drugs in their standard formulation. Furthermore, body fluids can be easily extracted for analysis by a reverse use of HMNs, thus making them perfect for sensing issues and theranostics applications. The fabrication of HMNs usually requires several many-step processes, increasing the costs and consequently decreasing the commercial interest. Photolithography is a well-known fabrication technique in microelectronics and microfluidics that fabricates MNs. In this paper, authors show a proof of concept of a patented, easy and one-shot fabrication of two kinds of HMNs: (1) Symmetric HMNs with a “volcano” shape, made by using a photolithographic mask with an array of transparent symmetric rings; and (2) asymmetric HMNs with an oblique aperture, like standard hypodermic steel needles, made by using an array of transparent asymmetric rings, defined by two circles, which centers are slightly mismatched. Simulation of light propagation, fabrication process, and preliminary results on ink microinjection are presented.

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Kong, Seonho, Jin Chul Yang et Jin Young Park. « Caffeine-imprinted conducting polymeric films with 2D hierarchical pore arrays prepared via colloidal mask-assisted electrochemical polymerization ». Sensors and Actuators B : Chemical 260 (mai 2018) : 587–92. http://dx.doi.org/10.1016/j.snb.2018.01.070.

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Kolya, Haradhan, et Chun-Won Kang. « A New Approach for Agricultural Water Management Using Pillows Made from COVID-19 Waste Face Masks and Filled with a Hydrogel Polymer : Preliminary Studies ». Agriculture 13, n^o 1 (6 janvier 2023) : 152. http://dx.doi.org/10.3390/agriculture13010152.

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Face masks have become an essential commodity during the COVID-19 pandemic, and their use rises daily. Excessive face mask use will likely continue to combat the virus and bacterial impacts in the long term. Afterward, used face masks are hazardous to the environment since most are made of nonbiodegradable porous polymeric fibrous materials. Thus, finding new ways to recycle waste face masks is urgently needed. Similarly, managing agricultural water for irrigation is a crucial challenge in saving water. This study demonstrates an approach for recycling face masks as bag- or small-sized pillows filled with superabsorbent polymers (SAPs) for the slow release of water near plant roots. Previous studies have reported that SAPs or hydrogel could boost soil’s water retention capacity, mixed with hydrogel/SAP. However, mixing SAPs into soil is improper because biodegradation generates low toxic organic molecules and contaminates soil and surface water. The objective of this research was to develop a face mask reuse approach, reduce irrigation water using polymers, and reduce toxic contamination in the soil. Here, swollen SAPs were taken inside the pillow and buried near plants, and the growth of the plants was studied. The moisture of the inner soil was constant for a long time, boosting plant growth. Afterward, the face mask pillows could be removed from the soil and maintained for further use. This new approach could be helpful in pot farming. This approach could contribute to the circular economy and the development of environmental sustainability.

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Sarkar, Sudipta K., et Dipti Gupta. « Low temperature flash light curing of spray coated zirconium oxide gate dielectric for flexible, fully patterned and low voltage operated organic thin film transistor ». MRS Advances 2, n^o 23 (2017) : 1273–78. http://dx.doi.org/10.1557/adv.2017.289.

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ABSTRACTIn this work, we present low temperature flash light based curing of spray coated high-k zirconium oxide (ZrOx) thin film to realize low voltage operated flexible and fully patterned organic thin film transistors (OTFTs). A simple sol-gel technique was followed to prepare ZrOx from a zirconium complex. By spraying the precursor solution onto substrate through shadow mask, a patterned film was obtained. On the other hand subsequent flash light curing of the coated film not only reduced processing time but also allowed us to fabricate device on polymeric flexible substrate. Spectroscopic analysis confirmed formation of ZrOx film from the solution of zirconium complex. Finally as prepared ZrOx was used as gate dielectric layer in OTFT structure to keep operating voltage as low as -3V. Flexible polyethylenetrephthalate (PET) sheet was used as flexible substrate and pentacene was used as organic active layer. Each and every layer was deposited through metal made shadow mask to develop fully patterned OTFT. Field effect mobility and ON/OFF ratio of as fabricated transistor was found to be as high as 1.2 cm2V-1S-1 and 105 respectively.

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Dizbay-Onat, Melike. « Evaluation of Physical Adsorption Properties of the Activated Carbon Layers Used in the Commercial Face Mask Inserts ». Eng 4, n^o 1 (1 février 2023) : 434–43. http://dx.doi.org/10.3390/eng4010026.

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When the coronavirus disease 2019 (COVID-19) pandemic spread globally, wearing face masks in public became one of the most effective protective measures. Subsequently, due to the increasing demand for face masks, researchers explored feasible approaches to optimize their efficiency. The outcome of this research provides insights into the adsorption performance of four commercial face mask filter inserts with activated carbon layers (ACL). The results showed that the ACL of the inserts has very low Brunauer, Emmett, and Teller (BET) surface areas (2–33 m2/g) and low carbon percentages (19–31%). Physical adsorption analysis revealed non-uniform micropore size distributions in all samples. In addition, non-woven structures were obtained through scanning electron microscopy (SEM). The experimental outcomes show that the ACL in the purchased face masks is low-quality adsorbent and not pure carbonaceous material; polymeric components may be predominant.

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Parvulescu, Catalin, Elena Manea, Paul Schiopu et Raluca Gavrila. « Fabrication of Micro-Lens Array Obtained by Anisotropic Wet Etching of Silicon ». Defect and Diffusion Forum 369 (juillet 2016) : 71–76. http://dx.doi.org/10.4028/www.scientific.net/ddf.369.71.

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This paper presents the fabrication of a micro-lens array surface with a single-mask process and two etching steps with KOH water solution. Numerical analysis of optics was used to determine the optimal design parameters such as curvature sagitta and radius. The dimension of each lens is 20μm x 20μm. We used anisotropic etching of <100> silicon through a circular and squar mask to produce a pyramidal pit formed by four (111) planes. The oxide mask is stripped and the immersion of the sample in the etchant solution favors the etching of (411) plane transforming the pit into a smooth hemispherical cavity. An intermediate stage exists when a wider 19.470 <411> - face pyramid replaces the initial 54.740 inverted pyramid. The dependence of surface roughness on concentration and temperature of KOH is investigated in the range of 25%-40% and 60°C-80°C, respectively, and compared between them. The surface profiles and roughness was characterized by AFM. The etching depth and radius of micro-lens array was obtained from the SEM images and AFM data. Also, the array of concave depressions was directly used as a mould for replication of KER-2500 transparent polymeric silicon from Shin-Etsu with a refractive index n=1.41. The perfectly matched array of micro-lenses can be detached from substrate and used as a local solar concentrator. Optical properties such as the focal length of the plano-convex micro-lens array, obtained by replication, are measured and analyzed.

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Brochocka, Agnieszka, Aleksandra Nowak et Paweł Kozikowski. « Influence of Carbon Sorbent Quantity on Breakthrough Time in Absorbent Filters for Antismog Half Mask Application ». Materials 15, n^o 2 (13 janvier 2022) : 584. http://dx.doi.org/10.3390/ma15020584.

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In this article, we present polymer non-woven fabrics with the addition of carbon sorbents being tested to estimate the breakthrough time and efficient protection against vapors present in smog. For this purpose, three substances were selected, which constitute an inhalation hazard and are smog components: cyclohexane, toluene, and sulfur dioxide. It was demonstrated that an increased quantity of carbon sorbent in polymeric filters significantly prolongs the breakthrough time. However, high sorbent quantities may increase the filter surface mass and air flow resistance. To optimize the protective parameters with functionality, a compromise between the two has to be found. By comparing the breakthrough times for different carbon sorbent quantities, the optimal filter composition was elaborated. The analyzed non-woven fabrics were manufactured by the melt-blown process and filled with ball-milled carbon sorbents supplied directly into the fabric blowing nozzle. Both protective performance and textural properties were analyzed for two commercially available carbon sorbents. Furthermore, it was proven that high values of sorbent-specific surface area translates directly into greater filter performance.

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Urbina, Javier, Rodrigo Tuesta, Luis Chirre, Antonella Hadzich et Santiago Flores. « Copper Tannate (CuTn) Based Coating on 3D Printed Face Masks ». Materials Science Forum 1066 (13 juillet 2022) : 93–98. http://dx.doi.org/10.4028/p-fvm81w.

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The impact of COVID-19 crisis on global supply chains caused a critical shortage of essential goods like medical devices. Additionally, massive consumption increased mask contamination and waste. 3D printing has become a fast and versatile manufacturing alternative that prevents a single use of masks. However, SARS-CoV-2 virus can persist on plastic surfaces for days. This study proposes the optimization of 3D printed masks, by applying a coating rich in hydrolyzable tannins and copper, in order to diminish the virus presence. Different paints were formulated with copper tannate and applied on thermoplastic polyurethane 3D panels to test bacterial stability. Results showed a significant reduction of colony-forming units on coated polymeric surfaces. Paints pigmented with copper tannates could improve the protection provided by printed masks, even against the COVID-19 virus.

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Cabral, Patrícia D., Telma Domingues, George Machado, Alexandre Chicharo, Fátima Cerqueira, Elisabete Fernandes, Emília Athayde, Pedro Alpuim et Jérôme Borme. « Clean-Room Lithographical Processes for the Fabrication of Graphene Biosensors ». Materials 13, n^o 24 (15 décembre 2020) : 5728. http://dx.doi.org/10.3390/ma13245728.

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This work is on developing clean-room processes for the fabrication of electrolyte-gate graphene field-effect transistors at the wafer scale for biosensing applications. Our fabrication process overcomes two main issues: removing surface residues after graphene patterning and the dielectric passivation of metallic contacts. A graphene residue-free transfer process is achieved by using a pre-transfer, sacrificial metallic mask that protects the entire wafer except the areas around the channel, source, and drain, onto which the graphene film is transferred and later patterned. After the dissolution of the mask, clean gate electrodes are obtained. The multilayer SiO2/SiNx dielectric passivation takes advantage of the excellent adhesion of SiO2 to graphene and the substrate materials and the superior impermeability of SiNx. It hinders native nucleation centers and breaks the propagation of defects through the layers, protecting from prolonged exposition to all common solvents found in biochemistry work, contrary to commonly used polymeric passivation. Since wet etch does not allow the required level of control over the lithographic process, a reactive ion etching process using a sacrificial metallic stopping layer is developed and used for patterning the passivation layer. The process achieves devices with high reproducibility at the wafer scale.

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Waegner, Martin, Mathias Schröder, Gunnar Suchaneck, Heinz Sturm, Christiane Weimann, Lukas M. Eng et Gerald Gerlach. « Domain Formation in Nano-patterned PZT Thin Films ». MRS Proceedings 1454 (2012) : 267–72. http://dx.doi.org/10.1557/opl.2012.1230.

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ABSTRACTIn this work, reactive magnetron-sputtered Pb(Zr,Ti)O3thin films were used to fabricate well-ordered nanodot arrays by means of nanosphere lithography (NSL). NSL is based on a two-step etch process by means of, firstly adjusting the diameter of polystyrene spheres in the self-assembled polymeric nanosphere mask using reactive ion etching, and secondly transferring the mask to the substrate by ion milling with adjusted heights. Hence, structures with different aspect ratios can be fabricated.Piezoresponse force microscopy was used as the inspection tool on both non-patterned and patterned films. Both the topography and polarization out of plane and in plane was deduced in this mode. Grains of nanodots with low aspect ratio form domain structures comparable to domains in non-patterned films. In contrast to that, nanodots with a higher aspect ratio form particular structures. The in-plane amplitude images show mostly a bisectioned domain assembly, while the out-of-plane amplitude images show in some cases more complex structures like “c”-shaped domains or multi-domains around a center domain.The patterning of the ferroelectric material was shown to affect the formation of ferroelectric domains. The initial polycrystalline, randomly-ordered films are re-oriented and show domain structures depending on nanodisc diameter and aspect ratio. This may enable tailoring of ferroelectric materials in their piezoelectric and pyroelectric properties by patterning.

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Tang, Tingji, Curt Planje, Ramachandran K. Trichur, Xing-Fu Zhong, Shelly Fowler, Gu Xu, Kimberly Yess, Xie Shao et Daniel J. Vestyck. « Novel Polymeric Protective Coatings for Hydrofluoric Acid Vapor Etching during MEMS Release Etch ». Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2010, DPC (1 janvier 2010) : 000942–70. http://dx.doi.org/10.4071/2010dpc-tp24.

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Micro-electro-mechanical system (MEMS) is rapidly becoming a critical part of advanced fabrication technology such as cellular phones, micromirrors, radio frequency (RF) devices, microprobes, and pressure sensors. Release etching of a sacrificial layer of silicon oxide plays an important role in creating the moving parts during these MEMS device fabrication. Traditionally, wet fluorinated etchants have been applied in order to achieve release etching, by which liquid surface tension can cause the MEMS microstructures to stick together (“stiction”) upon removing from aqueous bath or during the drying of released wet-etched structure. It has been demonstrated that using a hydrofluoric acid (HF) vapor release etch can efficiently circumvent stiction phenomena owing to the fact that it substantially eliminates the surface tension that causes the stiction. Conventionally, inorganic based films such as silicon nitride, alumina, SiC, polysilicon, amorphous silicon, and aluminum etc were used as vapor HF etch-resistant mask materials, which require very high temperature and vacuum deposition techniques often lengthy, complicated and costly. Herein, a novel spin-on and polymeric blanket HF-resistant coating material is presented to provide protection of both silicon oxide and aluminum against HF attack during vapor HF etching. Our newly developed polymeric coatings can be processed at lower temperature (<250 °C) and thinner films (less than 10μm) for extended vapor HF etching period (longer than 1 hour). Hence, our vapor HF resistant materials will enable the MEMS industry to significantly lower the cost of manufacturing MEMS devices and will significantly simplify the manufacturing process as well.

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Nurherdiana, Silvana Dwi. « Polymer Technology Outlook Study : Face Shields for Responding SARS-CoV2 Pandemic ». International Journal of Eco-Innovation in Science and Engineering 2, n^o 01 (7 juillet 2021) : 20–24. http://dx.doi.org/10.33005/ijeise.v2i01.38.

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The coronavirus disease 2019 (SARS-CoV2) has attracted most interest in current years due to the worst impact for the global public health. In this situation, the whole world requires wearing face shield and mask as the personal protective equipment, especially for medical personnel. Polymer technology have been introduced as a helping tool against SARS-CoV2 by producing healthcare product such as face shield as the first line of resistance due to it was cost effectiveness, sterile nature, versatility and easy to modify. This article clarifies the discussion about face shields in the polymer technology as the point of view and aims at providing a deeper understanding about polymer, polymeric material, synthesis methodology and its application for responding SARS-CoV2 pandemic in a form of face shields. The study of the synthesis route and methodology, chemical and physical properties of the polymer for face shields have also been described.

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Adhikari, Rameshwar, Suraj Baidya, Gaurav Das, Lekh Nath Khatiwada, Shankar Prasad Khatiwada, Tshering Lama, Ganesh Kunwar Chhetri et al. « Innovating protectives gears for frontline health professionals in the COVID-19 pandemic at a low resource setting ». Applied Science and Technology Annals 1, n^o 1 (30 juin 2020) : 48–50. http://dx.doi.org/10.3126/asta.v1i1.30272.

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We communicate briefly about the innovation of protective gear (such as Hazmat suit) and respirator mask that can be used by health care professionals as mouth and nose protection tools against the penetration of the microscopic particles containing highly contagious species into the body. As a research and development support to the local entrepreneurs willing to come up with innovative products, the structural and some surface functional properties of the polymeric materials available in local market were analyzed in comparison to the commercially available gears and masks. It has been found that the respirator masks, equivalent in structure and functional properties as the common commercially available protective gears could be developed that can be used by front-line health professionals for protection against contagious environment. The research has paved way to manufacture highly useful health care products at significantly lower costs under low resource setting.

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Ogbuoji, Ebuka A., Lauren Stephens, Amber Haycraft, Eric Wooldridge et Isabel C. Escobar. « Non-Solvent Induced Phase Separation (NIPS) for Fabricating High Filtration Efficiency (FE) Polymeric Membranes for Face Mask and Air Filtration Applications ». Membranes 12, n^o 7 (21 juin 2022) : 637. http://dx.doi.org/10.3390/membranes12070637.

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Protection against airborne viruses has become very relevant since the outbreak of SARS-CoV-2. Nonwoven face masks along with heating, ventilation, and air conditioning (HVAC) filters have been used extensively to reduce infection rates; however, some of these filter materials provide inadequate protection due to insufficient initial filtration efficiency (FE) and FE decrease with time. Flat sheet porous membranes, which have been used extensively to filter waterborne microbes and particulate matter due to their high FE have the potential to filter air pollutants without compromising its FE over time. Therefore, in this study, single layer polysulfone (PSf) membranes were fabricated via non-solvent induced phase separation (NIPS) and were tested for airflow rate, pressure drop and FE. Polyethylene glycol (PEG) and glycerol were employed as pore-forming agents, and the effect of the primary polymer and pore-forming additive molecular weights (MW) on airflow rate and pressure drop were studied at different concentrations. The thermodynamic stability of dope solutions with different MWs of PSf and PEG in N-methylpyrrolidone (NMP) at different concentrations was determined using cloud-point measurements to construct a ternary phase diagram. Surface composition of the fabricated membranes was characterized using contact angle and X-ray photoelectron spectroscopy (XPS), while membrane morphology was characterized by SEM, and tensile strength experiments were performed to analyze the membrane mechanical strength (MS). It was observed that an increase in PSf and PEG molecular weight and concentration increased airflow and decreased pressure drop. PSf60:PEG20:NMP (15:15:70)% w/w showed the highest air flow rate and lowest pressure drop, but at the expense of the mechanical strength, which was improved significantly by attaching the membrane to a 3D-printed polypropylene support. Lastly, the FE values of the membranes were similar to those of double-layer N95 filters and significantly higher than those of single layer of N95, surgical mask and HVAC (MERV 11) filters.

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Wasilewska, Katarzyna, et Katarzyna Winnicka. « Ethylcellulose–A Pharmaceutical Excipient with Multidirectional Application in Drug Dosage Forms Development ». Materials 12, n^o 20 (17 octobre 2019) : 3386. http://dx.doi.org/10.3390/ma12203386.

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Polymers constitute the most important group of excipients utilized in modern pharmaceutical technology, playing an essential role in the development of drug dosage forms. Synthetic, semisynthetic, and natural polymeric materials offer opportunities to overcome different formulative challenges and to design novel dosage forms for controlled release or for site-specific drug delivery. They are extensively used to design therapeutic systems, modify drug release, or mask unpleasant drug taste. Cellulose derivatives are characterized by different physicochemical properties, such as swellability, viscosity, biodegradability, pH dependency, or mucoadhesion, which determine their use in industry. One cellulose derivative with widespread application is ethylcellulose. Ethylcellulose is used in pharmaceutical technology as a coating agent, flavoring fixative, binder, filler, film-former, drug carrier, or stabilizer. The aim of this article is to provide a broad overview of ethylcellulose utilization for pharmaceutical purposes, with particular emphasis on its multidirectional role in the development of oral and topical drug dosage forms.

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Carreiras-Suárez, Sandra, Lidia Domínguez-Ramos et Massimo Lazzari. « Study of the Long-Term Aging of Polypropylene-Made Disposable Surgical Masks and Filtering Facepiece Respirators ». Polymers 15, n^o 4 (17 février 2023) : 1001. http://dx.doi.org/10.3390/polym15041001.

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The main purpose of this work is to contribute to understanding the mechanism of oxidation of the polymeric components of common disposable masks used during the COVID-19 pandemic to offer the chemical basis to understand their long-term behavior under typical environmental conditions. Artificial aging of representative mask layers under isothermal conditions (110 °C) or accelerated photoaging showed that all the PP-made components underwent a fast oxidation process, following the typical hydrocarbon oxidation mechanism. In particular, yellowing and the melting temperature drop are early indicators of their diffusion-limited oxidation. Morphology changes also induced a loss of mechanical properties, observable as embrittlement of the fabric fibers. Results were validated through preliminary outdoor aging of masks, which allows us to predict they will suffer fast and extensive oxidation only in the case of contemporary exposure to sunlight and relatively high environmental temperature, leading to their extensive breakdown in the form of microfiber fragments, i.e., microplastics.

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Militky, Jiri, Ondrej Novak, Dana Kremenakova, Jakub Wiener, Mohanapriya Venkataraman, Guocheng Zhu, Juming Yao et Arun Aneja. « A Review of Impact of Textile Research on Protective Face Masks ». Materials 14, n^o 8 (13 avril 2021) : 1937. http://dx.doi.org/10.3390/ma14081937.

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COVID-19, classified as SARS-CoV-2, is causing an ongoing global pandemic. The pandemic has resulted in the loss of lives and has caused economic hardships. Most of the devices used to protect against the transmission of the novel COVID-19 disease are related to textile structures. Hence, the challenge for textile professionals is to design and develop suitable textile structures with multiple functionalities for capturing viruses, passivating them, and, at the same time, having no adverse effects on humans during the complete period of use. In addition to manufacturing efficient, biocompatible, and cost-effective protective face masks, it is also necessary to inform the public about the benefits and risks of protective face mask materials. The purpose of this article is to address the concerns of efficiency and efficacy of face masks by primarily reviewing the literature of research conducted at the Technical University of Liberec. The main focus is on the presentation of problems related to the specification of aims of face mask applications, mechanisms of capture, durability, and modes of sterilization. The recommendations, instead of conclusions, are addressed to the whole textile society because they should be leading players in the design, creation, and proper treatment of face masks due to their familiarity with the complex behavior of textile structures and targeted changes of structural hierarchy starting from polymeric chains (nano-level) and ending in planar textile structures (millimeter level) due to action by mechanical, physical and chemical fields. This becomes extremely critical to saving hundreds of thousands of lives from COVID-19.

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Hiiuk, Volodymyr M., Vasyl Mykhailovych, Sergiu Shova, Irina A. Golenya et Il'ya A. Gural'skiy. « Crystal structure of poly[[diaquatetra-μ₂-cyanido-platinum(II)iron(II)] methanol 4/3-solvate] : a three-dimensional Hofmann clathrate analogue ». Acta Crystallographica Section E Crystallographic Communications 78, n^o 2 (25 janvier 2022) : 216–19. http://dx.doi.org/10.1107/s2056989022000573.

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In the title polymeric coordination compound, {[FePt(CN)4(H2O)2]·1.33CH3OH} n , the FeII cation (site symmetry 4/mm.m) is coordinated by the N atoms of four cyanide anions (CN−) and the O atoms of two water molecules, forming a nearly regular [FeN4O2] octahedron. According the Fe—N and Fe—O bond lengths, the FeII atom is in the high-spin state. The cyanide anions act in a bridging manner to connect the FeII and PtII atoms. The [Pt(CN)4]2– moieties (Pt with site symmetry 4/mm.m) have a perfect square-planar shape. The latter anion is located perpendicular to the FeN4 plane, thus ensuring the creation of a three-dimensional framework. The crystal structure features methanol solvent molecules of which 4/3 were located per FeII cation. These solvent molecules are located in hexagonal pores; they interact with coordinating water molecules through weak hydrogen bonds. Other guest molecules could not be modelled in a satisfactory way and their contribution to the scattering was removed by a mask procedure.

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Martínez, Alba, Sandra González-Lana, Laura Asín, Jesús M. de la Fuente, Cees W. M. Bastiaansen, Dirk J. Broer et Carlos Sánchez-Somolinos. « Nano-Second Laser Interference Photoembossed Microstructures for Enhanced Cell Alignment ». Polymers 13, n^o 17 (31 août 2021) : 2958. http://dx.doi.org/10.3390/polym13172958.

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Photoembossing is a powerful photolithographic technique to prepare surface relief structures relying on polymerization-induced diffusion in a solventless development step. Conveniently, surface patterns are formed by two or more interfering laser beams without the need for a lithographic mask. The use of nanosecond pulsed light-based interference lithography strengthens the pattern resolution through the absence of vibrational line pattern distortions. Typically, a conventional photoembossing protocol consists of an exposure step at room temperature that is followed by a thermal development step at high temperature. In this work, we explore the possibility to perform the pulsed holographic exposure directly at the development temperature. The surface relief structures generated using this modified photoembossing protocol are compared with those generated using the conventional one. Importantly, the enhancement of surface relief height has been observed by exposing the samples directly at the development temperature, reaching approximately double relief heights when compared to samples obtained using the conventional protocol. Advantageously, the light dose needed to reach the optimum height and the amount of photoinitiator can be substantially reduced in this modified protocol, demonstrating it to be a more efficient process for surface relief generation in photopolymers. Kidney epithelial cell alignment studies on substrates with relief-height optimized structures generated using the two described protocols demonstrate improved cell alignment in samples generated with exposure directly at the development temperature, highlighting the relevance of the height enhancement reached by this method. Although cell alignment is well-known to be enhanced by increasing the relief height of the polymeric grating, our work demonstrates nano-second laser interference photoembossing as a powerful tool to easily prepare polymeric gratings with tunable topography in the range of interest for fundamental cell alignment studies.

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Murrieta-Rico, Fabian N., Rosario I. Yocupicio-Gaxiola, Joel Antúnez-García, Armando Reyes-Serrato, Perla Sánchez et Vitalii Petranovskii. « Textile Functionalization Using LTA and FAU Zeolitic Materials ». Polymers 15, n^o 1 (26 décembre 2022) : 99. http://dx.doi.org/10.3390/polym15010099.

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COVID-19 has drawn worldwide attention to the need for personal protective equipment. Face masks can be transformed from passive filters into active protection. For this purpose, it is sufficient to apply materials with oligodynamic effect to the fabric of the masks, which makes it possible to destroy infectious agents that have fallen on the mask with aerosol droplets from the air stream. Zeolites themselves are not oligodynamic materials, but can serve as carriers for nanoparticles of metals and/or compounds of silver, zinc, copper, and other materials with biocidal properties. Such a method, when the particles are immobilized on the surface of the substrate, will increase the lifetime of the active oligodynamic material. In this work, we present the functionalization of textile materials with zeolites to obtain active personal protective equipment with an extended service life. This is done with the aim to extend the synthesis of zeolitic materials to polymeric fabrics beyond cotton. The samples were characterized using XRD, SEM, and UV-Vis spectroscopy. Data of physicochemical studies of the obtained hybrid materials (fabrics with crystals grown on fibers) will be presented, with a focus on the effect of fabrics in the growth process of zeolites.

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Gazioglu, Dilek Taskin, Fatih Dumludag, Mustafa Coskun et Savas Berber. « Fabrication and characterization of P3HT --- based OFETs with TPU --- polymeric gate dielectric prepared by electrospinning method with different thicknesses ». Физика и техника полупроводников 56, n^o 7 (2022) : 719. http://dx.doi.org/10.21883/ftp.2022.07.52767.9808a.

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Current work reports the manufacturing and electrical characteristics of organic field-effect transistors in the top-contact bottom-gate configurations utilizing solution - processed poly (3-hexylthiophene) films as an active semiconducting layer and thermoplastic polyurethane as gate insulator. A spin coating chemical polymerization technology and an electrospinning tool for polymeric mats production were used to prepare uniform organic thin films with controlled thickness from their solutions. Commercially available flat glass slides were used as the starting substrate. To form the gate electrode a thin layer of metal such as gold (Au) or silver (Ag) was deposited on the glass surface substrates by thermal evaporation through a shadow mask. Thermoplastic polyurethane insulating films with different thicknesses were electrospun from precursor solution on the substrates with Au or Ag electrodes. Patterned Au and/or Ag drain and source electrodes were deposited directly on the surface of as - fabricated poly(3-hexylthiophene) organic semiconductor layer. We used two kinds of metals that have different work functions and their combinations to investigate the influence of the source, drain and gate electrode materials on the output characteristics of fabricated organic thin film transistors. All fabricated of organic field-effect transistor devices showed typical p-type channel characteristics. Additionally, the effects of thermoplastic polyurethane gate dielectric thickness as well as the influence of processing parameters on electrical performances of organic field-effect transistors fabricated were also investigated. Results show that all developed transistors exhibit good and stable performance up to a relatively high drain voltage of ~50 V and the drain-source current up to ~0.5 μA. Keywords: organic field-effect transistors, P3HT organic semiconductor, TPU gate dielectric, electrical characteristics.

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Reinas, Alexandre Espada, Jaqueline Hoscheid, Priscila Miyuki Outuki et Mara Lane Carvalho Cardoso. « Preparation and characterization of microcapsules of Pterodon pubescens Benth. by using natural polymers ». Brazilian Journal of Pharmaceutical Sciences 50, n^o 4 (décembre 2014) : 919–30. http://dx.doi.org/10.1590/s1984-82502014000400028.

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An oleaginous fraction obtained from an alcohol extract of the fruit of Pterodon pubescensBenth. (FHPp) was microencapsulated in polymeric systems. These systems were developed using a complex coacervation method and consisted of alginate/medium-molecular-weight chitosan (F1-MC), alginate/chitosan with greater than 75% deacetylation (F2-MC), and alginate/low-molecular-weight chitosan (F3-MC). These developed systems have the potential to both mask the taste of the extract, and to protect its constituents against possible chemical degradation. The influence of the formulation parameters and process were determined by chemical profiling and measurement of the microencapsulation efficiency of the oleaginous fraction, and by assessment of microcapsule morphology. The obtained formulations were slightly yellow, odorless, and had a pleasant taste. The average diameters of the microcapsules were 0.4679 µm (F2-MC), 0.5885 µm (F3-MC), and 0.9033 µm (F1-MC). The best formulation was F3-MC, with FHPp microencapsulation efficiency of 61.01 ± 2.00% and an in vitro release profile of 75.88 ± 0.45%; the content of vouacapans 3-4 was 99.49 ± 2.80%. The best model to describe the release kinetics for F1-MC and F3-MC was that proposed by Higuchi; however, F2-MC release displayed first-order kinetics; the release mechanism was of the supercase II type for all formulations.

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Wang, Yuer, Huahao Fan et Yigang Tong. « Unveil the Secret of the Bacteria and Phage Arms Race ». International Journal of Molecular Sciences 24, n^o 5 (22 février 2023) : 4363. http://dx.doi.org/10.3390/ijms24054363.

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Bacteria have developed different mechanisms to defend against phages, such as preventing phages from being adsorbed on the surface of host bacteria; through the superinfection exclusion (Sie) block of phage’s nucleic acid injection; by restricting modification (R-M) systems, CRISPR-Cas, aborting infection (Abi) and other defense systems to interfere with the replication of phage genes in the host; through the quorum sensing (QS) enhancement of phage’s resistant effect. At the same time, phages have also evolved a variety of counter-defense strategies, such as degrading extracellular polymeric substances (EPS) that mask receptors or recognize new receptors, thereby regaining the ability to adsorb host cells; modifying its own genes to prevent the R-M systems from recognizing phage genes or evolving proteins that can inhibit the R-M complex; through the gene mutation itself, building nucleus-like compartments or evolving anti-CRISPR (Acr) proteins to resist CRISPR-Cas systems; and by producing antirepressors or blocking the combination of autoinducers (AIs) and its receptors to suppress the QS. The arms race between bacteria and phages is conducive to the coevolution between bacteria and phages. This review details bacterial anti-phage strategies and anti-defense strategies of phages and will provide basic theoretical support for phage therapy while deeply understanding the interaction mechanism between bacteria and phages.

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Baumers, Martin, Ricky Wildman, Martin Wallace, Jae Yoo, Brett Blackwell, Phil Farr et Clive J. Roberts. « Using total specific cost indices to compare the cost performance of additive manufacturing for the medical devices domain ». Proceedings of the Institution of Mechanical Engineers, Part B : Journal of Engineering Manufacture 233, n^o 4 (13 juin 2018) : 1235–49. http://dx.doi.org/10.1177/0954405418774591.

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The label additive manufacturing, also known as three-dimensional printing, serves as an umbrella term for a number of technologies designed to deposit product geometries directly from build materials and digital design information. However, as a relatively recent addition to the spectrum of manufacturing processes, the relationship between process type, system characteristics and cost performance is still broadly unclear for several technology types. To address this gap, the current research develops comprehensive and robust additive manufacturing cost models for two less-studied polymeric additive manufacturing technology variants, material jetting and mask projection stereolithography. Despite sharing the fundamental principle of photopolymerization, the operating processes of both systems are markedly different. This is reflected in the constructed cost models, which incorporate process maps to capture ancillary process elements, ensure efficient capacity utilisation through optimised build volume packing and approximate the expected cost impact of build failure. On this basis, this article estimates a set of specific cost indices reflecting the overall total cost performance of the investigated systems in an example application from the medical devices domain. Specific cost results range from £2.01 to £1.19/cm3 deposited on the Objet Connex 260 system and from £1.59 to £1.00/cm3 of material deposited on the Perfactory system. These results are discussed in the context of similar cost indices extracted from the empirical engineering literature. This article shows that next to increases in build speed, improvements in overall process automation and process stability are needed to enhance the commercial proposition of the investigated technology variants.

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Abou-Taleb, Heba A., Wesam W. Mustafa, Tarek Saad Makram, Lamiaa N. Abdelaty, Hesham Salem et Hamdy Abdelkader. « Vardenafil Oral Dispersible Films (ODFs) with Advanced Dissolution, Palatability, and Bioavailability ». Pharmaceutics 14, n^o 3 (26 février 2022) : 517. http://dx.doi.org/10.3390/pharmaceutics14030517.

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Oral, quick response, and on demand, also known as a spontaneous oral treatment for erectile dysfunction, is highly needed by both patients and physicians. Vardenafil is selective (fewer side effects) and more effective in difficult-to-treat conditions than sildenafil. This study aims at fostering the dual objectives of using biomolecules such as artificial sweetening agents to solubilize and mask the bitterness of vardenafil loaded on biodegradable polymeric materials (PVA, MC, SA, and PVP K30) to fabricate oral, fast-dissolving films (vardenafil ODFs) in the mouth without the need for water to ingest the dosage form. Furthermore, coprecipitated-dispersed mixtures of vardenafil and three sweeteners (sorbitol, acesulfame K, and sucralose) were prepared and characterized using FTIR, DSC, and solubility studies. Moreover, eight different vardenafil ODFs were prepared using the solvent-casting method. Modified gustatory sensation test, in vitro disintegration, and release studies were performed. In addition, the optimized ODF (F8) was compared with the commercial film-coated tablets pharmacokinetically (relative bioavailability, onset, and duration of actions were estimated). The results indicated that the three sweetening agents had comparable solubilizing capacity. However, both sucralose- and acesulfame K-based ODFs have a more enhanced sweet and palatable taste than sorbitol-sweetened ODF. The SA- and PVP K30-based ODFs showed significantly faster disintegration times and release rates than MC. In conclusion, PVA has good film-forming properties, but a higher ratio of PVA adversely affected the disintegration and release characteristics. The % relative bioavailability for ODF was 126.5%, with a superior absorption rate constant (Ka) of 1.2-fold. The Cmax and estimated Tmax were compared to conventional film-coated tablets.

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Ruiz-Velasco, Gabriela, Francisco Martínez-Flores, Juan Morales-Corona, Roberto Olayo-Valles et Roberto Olayo. « Polymeric Scaffolds For Skin ». Macromolecular Symposia 374, n^o 1 (août 2017) : 1600133. http://dx.doi.org/10.1002/masy.201600133.

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Hwang, Sun-Tak. « Adsorbent-filled polymeric membranes ». Macromolecular Symposia 118, n^o 1 (juin 1997) : 407–12. http://dx.doi.org/10.1002/masy.19971180154.

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Mang, Thomas, et Friedhelm Haulena. « Recycling of polymeric composites ». Macromolecular Symposia 135, n^o 1 (décembre 1998) : 147–56. http://dx.doi.org/10.1002/masy.19981350117.

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Dean, Robert N., et Lauren E. Beckingham. « A PCB Sensor for Magnetic Materials ». Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2019, DPC (1 janvier 2019) : 001323–42. http://dx.doi.org/10.4071/2380-4491-2019-dpc-presentation_tha3_026.

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Printed circuit board (PCB) sensors are a sensor technology where the layout of traces on a PCB has been optimized so that the traces electromagnetically interact with the surrounding environment. These types of sensors can be manufactured at very low cost using standard commercially available low-cost printed circuit board fabrication. Exposed conductive electrodes on the circuit board are useful for measuring the electrical conductivity of the surrounding environment, and these sensors have been used in applications such as salinity measurement and dissolved ion content measurement of aqueous solutions. Insulated interdigitated electrode sensors are useful for capacitively analyzing the surrounding environment, and these sensors have been used to detect the presence of liquid water and to measure the moisture content of substances in physical contact with the sensor. Additionally, by measuring the complex impedance of the capacitive sensor over a wide frequency range, information concerning the chemical composition of the substance in contact with the sensor can be determined. In addition to conducive and capacitive PCB sensors, the third type of PCB sensor would be an inductive sensor. Although it is challenging to realize 3D coils in PCB technology, planar inductors can be realized in a single Cu layer on a PCB, and insulated from the environment using a cover layer of polymeric solder mask. This type of electrode structure can inductively couple with magnetic materials in close proximity to the sensor. A variety of magnetic materials exist, including iron, nickel and cobalt. Additionally, many alloys of these elements are also magnetic. Of particular interest are corrosion products with magnetic properties, such as iron(III) oxide, Fe3O2, also known as common rust. A thin layer of iron(III) oxide powder deposited on the sensor's active area results in a measureable increase in the sensor's inductance. As such, an inductive PCB sensor could be a low-cost option for detecting the presence of some corrosion products in its operating environment.

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Karakosta, Paraskevi, Eleni Koumlili, Olga Kammona et Costas Kiparissides. « Antimicrobial Agent-Containing Polymeric Materials ». Macromolecular Symposia 331-332, n^o 1 (octobre 2013) : 144–51. http://dx.doi.org/10.1002/masy.201300085.

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Esposito, Elisabetta, et Rita Cortesi. « Polymeric microparticles for fenretinide administration ». Macromolecular Symposia 345, n^o 1 (novembre 2014) : 14–23. http://dx.doi.org/10.1002/masy.201400054.

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Braun, Dietrich, et Goetz P. Hellmann. « Chemical modification of polymeric hydrocarbons ». Macromolecular Symposia 129, n^o 1 (mars 1998) : 43–51. http://dx.doi.org/10.1002/masy.19981290105.

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Möhwald, Helmuth, Heinz Lichtenfeld, S. Moya, Andreas Voigt, H. Bäumler, Gleb Sukhorukov, Frank Caruso et Edwin Donath. « From polymeric films to nanoreactors ». Macromolecular Symposia 145, n^o 1 (octobre 1999) : 75–81. http://dx.doi.org/10.1002/masy.19991450109.

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