Journal articles on the topic 'Polymers in medicine – Testing'
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1
Salim, Mohammad, Riyanto Teguh Widodo, and Mohamed Ibrahim Noordin. "Proof-of-Concept of Detection of Counterfeit Medicine through Polymeric Materials Analysis of Plastics Packaging." Polymers 13, no. 13 (June 30, 2021): 2185. http://dx.doi.org/10.3390/polym13132185.
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The detection of counterfeit pharmaceuticals is always a major challenge, but the early detection of counterfeit medicine in a country will reduce the fatal risk among consumers. Technically, fast laboratory testing is vital to develop an effective surveillance and monitoring system of counterfeit medicines. This study proposed the combination of Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and Differential Scanning Calorimetry (DSC) for the quick detection of counterfeit medicines, through the polymer analysis of blister packaging materials. A sample set containing three sets of original and counterfeit medicine was analyzed using ATR-FTIR and DSC, while the spectra from ATR-FTIR were employed as a fingerprint for the polymer characterization. Intending to analyze the polymeric material of each sample, DSC was set at a heating rate of 10 °C min−l and within a temperature range of 0- 400 °C, with nitrogen as a purge gas at a flow rate of 20 ml min−an. The ATR-FTIR spectra revealed the chemical characteristics of the plastic packaging of fake and original medicines. Further analysis of the counterfeit medicine’s packaging with DSC exhibited a distinct difference from the original due to the composition of polymers in the packaging material used. Overall, this study confirmed that the rapid analysis of polymeric materials through ATR-FTIR and comparing DSC thermograms of the plastic in their packaging effectively distinguished counterfeit drug products.
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Kejlová, K., J. Labský, D. Jírová, and H. Bendová. "Hydrophilic polymers—biocompatibility testing in vitro." Toxicology in Vitro 19, no. 7 (October 2005): 957–62. http://dx.doi.org/10.1016/j.tiv.2005.06.032.
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Panin, Sergey V., Jiangkun Luo, Dmitry G. Buslovich, Vladislav O. Alexenko, Lyudmila A. Kornienko, Anton V. Byakov, Vitaly N. Paimushin, and Artur R. Shugurov. "Role of Testing Conditions in Formation of Tribological Layers at Line Contacts of Antifriction CF-Reinforced PI- and PEI-Based Composites." Molecules 27, no. 19 (September 27, 2022): 6376. http://dx.doi.org/10.3390/molecules27196376.
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High-strength PI and PEI polymers differ by chemical structure and flexibility of the polymer chains that ensure lower cost and higher manufacturability of the latter. The choice of a particular polymer matrix is of actuality at design of antifriction composites on their basis. In this study, a comparative analysis of tribological behavior of PI and PEI- based composites was carried out with linear contact rubbing. The neat materials, as well as the two- and three-component composites reinforced with chopped carbon fibers, were investigated. The third components were typically used, but were different in nature (polymeric and crystalline) being solid lubricant fillers (PTFE, graphite and MoS2) with characteristic dimensions of several microns. The variable parameters were both load and sliding speed, as well as the counterface material. It was shown that an improvement of the tribological properties could be achieved by the tribological layer formation, which protected their wear track surfaces from the cutting and plowing effects of asperities on the surfaces of the metal and ceramic counterparts. The tribological layers were not formed in both neat polymers, while disperse hardening by fractured CF was responsible for the tribological layer formation in both two- and three component PI- and PEI-based composites. The effect of polymer matrix in tribological behavior was mostly evident in two-component composites (PI/CF, PEI/CF) over the entire P⋅V product range, while extra loading with Gr and MoS2 leveled the regularities of tribological layer formation, as well as the time variation in friction coefficients.
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Kreß, Sebastian, Roland Schaller-Ammann, Jürgen Feiel, Joachim Priedl, Cornelia Kasper, and Dominik Egger. "3D Printing of Cell Culture Devices: Assessment and Prevention of the Cytotoxicity of Photopolymers for Stereolithography." Materials 13, no. 13 (July 6, 2020): 3011. http://dx.doi.org/10.3390/ma13133011.
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3D printing is increasingly important for the rapid prototyping of advanced and tailor-made cell culture devices. In this context, stereolithography represents a method for the rapid generation of prototypes from photocurable polymers. However, the biocompatibility of commercially available photopolymers is largely unknown. Therefore, we evaluated the cytotoxicity of six polymers, two of them certified as biocompatible according to ISO 10993-5:2009, and we evaluated, if coating with Parylene, an inert polymer widely used in medical applications, might shield cells from the cytotoxic effects of a toxic polymer. In addition, we evaluated the processability, reliability, and consistency of the details printed. Human mesenchymal stem cells (MSCs) were used for cytotoxicity testing as they are widely used and promising for numerous applications in regenerative medicine. MSCs were incubated together with printed photopolymers, and the cytotoxicity was assessed. All photopolymers significantly reduced the viability of MSCs while the officially biocompatible resins displayed minor toxic effects. Further, coating with Parylene completely protected MSCs from toxic effects. In conclusion, none of the tested polymers can be fully recommended for rapid prototyping of cell culture devices. However, coating with Parylene can shield cells from toxic effects and thus might represent a viable option until more compatible materials are available.
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TIMOSHIN, Anton, Nikolay MITIN, Alexander OLEYNIKOV, Maria TIMOSHINA, and Evgeniya MITINA. "CLINICAL AND LABORATORY TESTING OF A NEW MODIFICATION OF TWO-LAYER "SILEP" DENTURES USED IN PROSTHETIC DENTISTRY." SOUTHERN BRAZILIAN JOURNAL OF CHEMISTRY 28, no. 28 (June 20, 2020): 53–62. http://dx.doi.org/10.48141/sbjchem.v28.n28.2020.08_timoshin_pgs_53_62.pdf.
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Dentistry is a part of medicine, where various polymer materials were used for the first time. Many factors forced researchers to find more stable, versatile, and hygienic materials for the manufacture of dental products. It is important to note that the search for the ideal polymer dental material is still ongoing. This is because modern polymers, in some cases, do not meet the specified requirements for chemical, physical, strength, and elastic properties. Based on the data on the method of creating and using silicone material for the base of the removable prosthesis "Gossil", an improved silicone material for two-layer dentures "Silep" was developed, as well as a special primer for better connection of the lining with the rigid acrylic base of the prosthesis. To evaluate the most suitable compound, materials were tested for several parameters, such as tensile strength, elongation, and shore hardness. In addition to selecting a suitable material for modification, the selection and testing of an adhesive that allows the chemical bonding of the acrylate surface to the siloxane surface were carried out.
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Timoshin, Anton, Nikolay Mitin, Alexander Oleynikov, Maria Timoshina, and Evgeniya Mitina. "Clinical and Laboratory Testing of a New Modification of Two-Layer "Silep" Dentures Used in Prosthetic Dentistry." Southern Brazilian Journal of Chemistry 28, no. 28 (June 20, 2020): 53–62. http://dx.doi.org/10.37633/sbjc.28(28)2020.53-62.
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Dentistry is a part of medicine, where various polymer materials were used for the first time. Many factors forced researchers to find more stable, versatile, and hygienic materials for the manufacture of dental products. It is important to note that the search for the ideal polymer dental material is still ongoing. This is because modern polymers, in some cases, do not meet the specified requirements for chemical, physical, strength, and elastic properties. Based on the data on the method of creating and using silicone material for the base of the removable prosthesis "Gossil", an improved silicone material for two-layer dentures "Silep" was developed, as well as a special primer for better connection of the lining with the rigid acrylic base of the prosthesis. To evaluate the most suitable compound, materials were tested for several parameters, such as tensile strength, elongation, and shore hardness. In addition to selecting a suitable material for modification, the selection and testing of an adhesive that allows the chemical bonding of the acrylate surface to the siloxane surface were carried out
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J. Mohmmed, Mohmmed, Khalid M. Owaid, and Raouf M. Raouf. "Studies on the Microstructure of Epoxy-Cement Mortar." ECS Transactions 107, no. 1 (April 24, 2022): 17979–97. http://dx.doi.org/10.1149/10701.17979ecst.
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Introduction of polymers into the cement composites improves same of the properties of concretes and mortars. Therefore, the polymer-cement composites are successfully used in construction. The model of microstructure formation in cement composites modified with thermoplastic polymer (pre-mix modifiers) has already been developed and successfully implemented. However, the formation of microstructure in the case of epoxy-cement composites (containing post-mix modifier) demonstrates same peculiarities which should be taken into account when modelling the process. The microstructure of epoxy-cement composites and its formation is discussed in the paper. The model is offered, formulated on the basis of the microscopic observations and results of testing.
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Smutz, W. P., A. U. Daniels, K. P. Andriano, E. P. France, and J. Heller. "Mechanical test methodology for environmental exposure testing of biodegradable polymers." Journal of Applied Biomaterials 2, no. 1 (December 1991): 13–22. http://dx.doi.org/10.1002/jab.770020103.
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Bujanić, Božo, and Matija Košak. "Testing the Force Absorption of Composite Materials to Select the Best for Making a Helmet." Tehnički glasnik 15, no. 4 (November 1, 2021): 581–84. http://dx.doi.org/10.31803/tg-20210513090824.
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The paper presents and describes the procedure of testing the materials that were available for the production of a multifunctional protective helmet. The procedure was carried out at the company Šestan-Busch d.o.o. as part of the EU project for the development and production of a multifunctional protective helmet. The test results showed that carbon fibers polymers as a composite material have the best impact absorption properties which was a key criterion for material selection. Other materials; glass fibers polymers, aramid fibers polymers and combinations in the test procedure showed worse results compared to the selected criterion.
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Kohan, Miroslav, Samuel Lancoš, Marek Schnitzer, Jozef Živčák, and Radovan Hudák. "Analysis of PLA/PHB Biopolymer Material with Admixture of Hydroxyapatite and Tricalcium Phosphate for Clinical Use." Polymers 14, no. 24 (December 7, 2022): 5357. http://dx.doi.org/10.3390/polym14245357.
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One trend in tissue engineering and regenerative medicine is the development of degradable composite polymers. The aim of this study was the comprehensive analysis of Polylactic acid (PLA) / Polyhydroxybutyrate (PHB) + Hydroxyapatite (HA)/ Tricalcium phosphate (TCP) material from filament production to mechanical testing of samples with different infills and the production of an implant replacement for an intervertebral disc. Filament Maker – Composer 450 (3devo; Netherlands) was used to produce filaments. Experimental samples and the implant for the intervertebral disc were made using FDM technology using a DeltiQ2 3D printer (Trilab, Czech Republic). Mechanical testing of experimental samples was performed on an Inspekt TABLE 5 kN (Hegewald & Peschke, Nossen, Germany). Microscopic analysis, cytotoxicity test, and filament diameter analysis using descriptive statistics were also part of the focus. The results of the analysis of the diameter of the filament show that the filament meets the prescribed standard. The cytotoxicity test for PLA/PHB + HA/TCP material showed no toxicity. Microscopic analysis showed an even distribution of the ceramic component in the composite polymer. Mechanical testing showed a reduction in mechanical properties with 75% and 50% of the filling of experimental samples. All experimental samples subjected to mechanical testing showed higher tensile and compressive strength values compared to the values of the mechanical properties of vertebral trabecular bones, as reported in the literature. It can therefore be concluded that the material under investigation, PLA/PHB + HA/TCP appears to be a suitable candidate for hard tissue replacement.
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Guazzotti, Valeria, Anita Gruner, Mladen Juric, Veronika Hendrich, Angela Störmer, and Frank Welle. "Migration Testing of GPPS and HIPS Polymers: Swelling Effect Caused by Food Simulants Compared to Real Foods." Molecules 27, no. 3 (January 26, 2022): 823. http://dx.doi.org/10.3390/molecules27030823.
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Migration kinetic data from general purpose polystyrene (GPPS) and high impact polystyrene (HIPS) were generated for a set of model substances as well as styrene monomer and oligomers at different temperatures (20 °C, 40 °C, 60 °C) using food simulants stipulated in the European Regulation (EU) 10/2011 and real foods like milk, cream and olive oil (20 °C, 40 °C). The extent of polymer swelling was characterized gravimetrically and visual changes of the test specimens after migration contact were recorded. Isooctane and 95% ethanol caused strong swelling and visual changes of HIPS, overestimating real migration into foods especially at high temperatures; GPPS was affected by isooctane only at 60 °C. With 50% ethanol, after 10 days contact at 60 °C or 40 °C both polymers were slightly swollen. Contrary, most of the real foods analyzed caused no detectable swelling or visual changes of the investigated polymers. This study demonstrates that the recommendations provided by EU regulations are not always in agreement with the physicochemical properties of styrenic polymers. The critical point remains the selection of adequate food simulants/testing conditions, since the high overestimation of aggressive media can lead to non-compliance of polystyrene materials even if the migration into real food would be of no concern.
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Abidin, Akhmad Zainal, R. B. Emil Trisatya Nuriman, Narendra Afian Pradipto, and Ridwan P. Putra. "Emulsion Polymers of Carboxymethyl Cellulose and Methyl Methacrylate with Sodium Dodecyl Sulfate Surfactant as Soil Stabilizer." Indo. J. Chem. Res. 9, no. 3 (January 30, 2022): 163–70. http://dx.doi.org/10.30598//ijcr.2022.9-abi.
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Polymer-based materials have gained considerable attention in the road construction sector due to their ability to improve the mechanical strength and durability of soil. In this study, carboxymethyl cellulose-methyl methacrylate (CMC-MMA) emulsion polymers were prepared from different MMA to CMC mass ratios with sodium dodecyl sulfate surfactant. The synthesized materials were homogeneously mixed with laterite soil, and their unconfined compressive strengths were measured using dry and wet methods on a universal testing machine. The results indicated that the polymers were obtained in high yields with optimum solids content. Characterization using Fourier transform infrared confirmed the homopolymerization probability of monomers in the materials with increased MMA fractions. In addition, the viscosity of the graft-copolymers measured at room temperature was in the range of 1.2-3.2 cP. The polymer-stabilized soils exhibited maximum unconfined compressive strengths of 564 and 162 psi, respectively, obtained from the dry and wet methods. In general, the rise of MMA fraction in the treated soils enhanced the compressive strength of the soil, with a slight increase in soil pH. This study unfolds the potential of cellulose-based materials that can be implemented in soil reinforcement technology.
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Puppi, Dario, Gianni Pecorini, and Gianluca Parrini. "Additive Manufacturing of Anatomical Poly(d,l-lactide) Scaffolds." Polymers 14, no. 19 (September 27, 2022): 4057. http://dx.doi.org/10.3390/polym14194057.
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Poly(lactide) (PLA) is one of the most investigated semicrystalline polymers for material extrusion (MEX) additive manufacturing (AM) techniques based on polymer melt processing. Research on its application for the development of customized devices tailored to specific anatomical parts of the human body can provide new personalized medicine strategies. This research activity was aimed at testing a new multifunctional AM system for the design and fabrication by MEX of anatomical and dog-bone-shaped PLA samples with different infill densities and deposition angles. In particular, a commercial PLA filament was employed to validate the computer-aided design (CAD) and manufacturing (CAM) process for the development of scaffold prototypes modeled on a human bone defect. Physical-chemical characterization of the obtained samples by 1H-NMR spectroscopy, size exclusion chromatography (SEC), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) demonstrated a small reduction of polymer molecular weight (~5%) due to thermal processing, as well as that the commercial polymer employed was a semicrystalline poly(d,l-lactide). Mechanical characterization highlighted the possibility of tuning elastic modulus and strength, as well as the elongation at break up to a 60% value by varying infill parameters.
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VYAS, URVASHI, NARENDRA GEHALOT, VIKAS JAIN, and S. C. MAHAJAN. "A REVIEW ON IN SITU GELLING SYSTEM FOR OPHTHALMIC DRUG DELIVERY." Current Research in Pharmaceutical Sciences 11, no. 4 (January 8, 2022): 98–106. http://dx.doi.org/10.24092/crps.2021.110402.
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Ophthalmic drug delivery systems are both fascinating and problematic due to the normal physiological properties of the eyes, which restrict ocular product bioavailability. The development of novel ocular dosage forms for current drugs in order to enhance efficacy and bioavailability, as well as patient compliance and convenience, has become a major focus in the pharmaceutical business. Ocular In-situ gelling systems are a novel type of eye drug delivery systems that begin as a solution but rapidly convert into a thick gel when implanted or inserted into an ocular cavity where active pharmaceuticals are continually delivered. This sol-to-gel phase conversion is influenced by a range of variables, including variations in pH, the presence of ions, and temperature fluctuations. Post-transplantation gel is chosen for its viscosity and bio adhesive qualities, which prolongs the gel's presence in the ocular area and also ensures that the medicine is released slowly and continuously, in contrast to typical eye drops and ointments. This article provides an overview of situ gels, their numerous techniques of gelling, the many types of polymers utilized in situ gels, their gel-based methodologies, and the polymeric testing of situ gels. KEYWORDS: Ophthalmic, In situ gel, bioavailability, polymers, novel, sol-to-gel phase
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Kjellstrand, Per, and Ulf Boberg. "Testing of Polymer Materials: What Methods Should be Used?" Alternatives to Laboratory Animals 19, no. 2 (April 1991): 222–25. http://dx.doi.org/10.1177/026119299101900214.
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Tests, performed over a ten-year period, on 653 polymers intended for use in extracorporeal renal replacement therapy, were evaluated. The test battery used included animal tests, in vitro tests and chemical tests. Some tests were found to have a very low sensitivity. Thus, acute systemic toxicity testing in mice with sodium chloride, ethanol or paraffin oil as extractants was performed on a total of 806 occasions. Only two of these resulted in a “fail” decision. The final outcome of the tests for the majority of materials could be predicted by the results of the UV absorption, chloride, inhibition of cell growth, and tin tests. Of the materials that passed these four tests, less than 2% were not approved on the basis of the whole test battery. The experiments show that only a limited number of tests have to be performed when testing polymers intended for use in extracorporeal renal replacement therapy.
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Senceroglu, Sait, Mohamed Arselene Ayari, Tahereh Rezaei, Fardad Faress, Amith Khandakar, Muhammad E. H. Chowdhury, and Zanko Hassan Jawhar. "Constructing an Intelligent Model Based on Support Vector Regression to Simulate the Solubility of Drugs in Polymeric Media." Pharmaceuticals 15, no. 11 (November 14, 2022): 1405. http://dx.doi.org/10.3390/ph15111405.
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This study constructs a machine learning method to simultaneously analyze the thermodynamic behavior of many polymer–drug systems. The solubility temperature of Acetaminophen, Celecoxib, Chloramphenicol, D-Mannitol, Felodipine, Ibuprofen, Ibuprofen Sodium, Indomethacin, Itraconazole, Naproxen, Nifedipine, Paracetamol, Sulfadiazine, Sulfadimidine, Sulfamerazine, and Sulfathiazole in 1,3-bis[2-pyrrolidone-1-yl] butane, Polyvinyl Acetate, Polyvinylpyrrolidone (PVP), PVP K12, PVP K15, PVP K17, PVP K25, PVP/VA, PVP/VA 335, PVP/VA 535, PVP/VA 635, PVP/VA 735, Soluplus analyzes from a modeling perspective. The least-squares support vector regression (LS-SVR) designs to approximate the solubility temperature of drugs in polymers from polymer and drug types and drug loading in polymers. The structure of this machine learning model is well-tuned by conducting trial and error on the kernel type (i.e., Gaussian, polynomial, and linear) and methods used for adjusting the LS-SVR coefficients (i.e., leave-one-out and 10-fold cross-validation scenarios). Results of the sensitivity analysis showed that the Gaussian kernel and 10-fold cross-validation is the best candidate for developing an LS-SVR for the given task. The built model yielded results consistent with 278 experimental samples reported in the literature. Indeed, the mean absolute relative deviation percent of 8.35 and 7.25 is achieved in the training and testing stages, respectively. The performance on the largest available dataset confirms its applicability. Such a reliable tool is essential for monitoring polymer–drug systems’ stability and deliverability, especially for poorly soluble drugs in polymers, which can be further validated by adopting it to an actual implementation in the future.
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Bochkarev, Leonid N., Yulia P. Parshina, Yana V. Gracheva, Tatyana A. Kovylina, Svetlana A. Lermontova, Larisa G. Klapshina, Aleksey N. Konev, et al. "Red Light-Emitting Water-Soluble Luminescent Iridium-Containing Polynorbornenes: Synthesis, Characterization and Oxygen Sensing Properties in Biological Tissues In Vivo." Molecules 26, no. 21 (October 20, 2021): 6349. http://dx.doi.org/10.3390/molecules26216349.
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New water-soluble polynorbornenes P1–P4 containing oligoether, amino acid groups and luminophoric complexes of iridium(III) were synthesized by ring-opening metathesis polymerization. The polymeric products in organic solvents and in water demonstrate intense photoluminescence in the red spectral region. The polymers P1 and P3 with 1-phenylisoquinoline cyclometalating ligands in iridium fragments reveal 4–6 fold higher emission quantum yields in solutions than those of P2 and P4 that contain iridium complexes with 1-(thien-2-yl)isoquinoline cyclometalating ligands. The emission parameters of P1–P4 in degassed solutions essentially differ from those in the aerated solutions showing oxygen-dependent quenching of phosphorescence. Biological testing of P1 and P3 demonstrates that the polymers do not penetrate into live cultured cancer cells and normal skin fibroblasts and do not possess cytotoxicity within the concentrations and time ranges reasonable for biological studies. In vivo, the polymers display longer phosphorescence lifetimes in mouse tumors than in muscle, as measured using phosphorescence lifetime imaging (PLIM), which correlates with tumor hypoxia. Therefore, preliminary evaluation of the synthesized polymers shows their suitability for noninvasive in vivo assessments of oxygen levels in biological tissues.
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Regev, Clil, Zhongyi Jiang, Roni Kasher, and Yifat Miller. "Distinct Antifouling Mechanisms on Different Chain Densities of Zwitterionic Polymers." Molecules 27, no. 21 (October 31, 2022): 7394. http://dx.doi.org/10.3390/molecules27217394.
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Antifouling polymer coating surfaces are used in widespread industries applications. Zwitterionic polymers have been identified as promising materials in developing polymer coating surfaces. Importantly, the density of the polymer chains is crucial for acquiring superior antifouling performance. This study introduces two different zwitterionic polymer density surfaces by applying molecular modeling tools. To assess the antifouling performance, we mimic static adsorption test, by placing the foulant model bovine serum albumin (BSA) on the surfaces. Our findings show that not only the density of the polymer chain affect antifouling performance, but also the initial orientation of the BSA on the surface. Moreover, at a high-density surface, the foulant either detaches from the surface or anchor on the surface. At low-density surface, the foulant does not detach from the surface, but either penetrates or anchors on the surface. The anchoring and the penetrating mechanisms are elucidated by the electrostatic interactions between the foulant and the surface. While the positively charged ammonium groups of the polymer play major role in the interactions with the negatively charged amino acids of the BSA, in the penetrating mechanism the ammonium groups play minor role in the interactions with the contact with the foulant. The sulfonate groups of the polymer pull the foulant in the penetrating mechanism. Our work supports the design of a high-density polymer chain surface coating to prevent fouling phenomenon. Our study provides for the first-time insights into the molecular mechanism by probing the interactions between BSA and the zwitterion surface, while testing high- and low-densities polymer chains.
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Silver, Frederick H., Michael Gonzalez-Mercedes, and Arielle Mesica. "A Rapid Method to Noninvasively Measure the Viscoelastic Properties of Synthetic Polymers Using Mechanical Vibrations and Photonics." Photonics 9, no. 12 (December 1, 2022): 925. http://dx.doi.org/10.3390/photonics9120925.
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Noninvasive measurement of the viscoelastic properties of both natural and synthetic polymers is important for the analysis of implant design and performance as well as in industrial material development. In this study, we used vibrational optical coherence tomography (VOCT) to compare the elastic and viscoelastic properties of silicone polymers with standard tensile stress–strain measurements. VOCT uses acoustic vibrations and infrared light to measure the resonant frequency of viscoelastic materials. The elastic modulus was calculated from the in-phase deformation of the material at fixed frequencies using an empirical calibration curve. Viscous loss was measured after pulsing the samples based on the ratio of mechanovibrational peak widths to heights. The results showed that the optimal cure time and modulus values obtained using VOCT were like those obtained using conventional tensile testing. VOCT could capture results that were comparable to conventional testing while not destroying the material, suggesting its usefulness for in vivo and in situ measurements as well as for early quality control environments during end-use application and fabrication experiments. We conclude that VOCT is a new technique that is comparable to conventional testing for noninvasively and nondestructively measuring the viscoelastic properties of polymers.
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Zapciu, A., C. Gh Amza, F. Baciu, and M. I. Vasile. "Heat treatment of 3D printed polyethylene terephthalate glycol in a supporting powder bed." IOP Conference Series: Materials Science and Engineering 1182, no. 1 (October 1, 2021): 012083. http://dx.doi.org/10.1088/1757-899x/1182/1/012083.
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Abstract Material extrusion 3D printing is a fabrication process that produces layered polymer parts with complex geometry but with inferior mechanical properties compared to parts made with other methods such as injection molding. Post fabrication heat treatment is a valid post-processing method that reduces the internal thermal stresses and improves layer adhesion in 3D printed polymers, resulting in superior mechanical properties. This study investigates the mechanical changes produced in 3D printed PETG (polyethylene terephthalate glycol-modified) parts after heat treatment. A novel technique is used, where the parts are embedded into a bed of sodium chloride powder in order to prevent deformation during postprocessing. Fully filled 3D printed PETG parts with various geometries are tightly packed in a bed of powder. The parts are subjected to heat treatment at a temperature above the material’s glass transition temperature but below its melting temperature. Destructive and non-destructive testing performed on the treated 3D printed samples shows a substantial improvement of mechanical properties. Tensile strength testing reveals an increase of tensile strength by 40% for parts printed horizontally and by over 100% for parts printed vertically. Increased stiffness is also observed in treated parts. Compressive strength testing shows a strength increase of 43% after treatment. Dimensional measurements made prior to and after treatment show significantly reduced deformation when using the supporting powder method versus unsupported treatment. Scanning electron microscopy (SEM) analysis is used to assess internal structural changes in the polymer after post-processing. This analysis reveals changes in internal void shape and distribution, increased interlayer adhesion and increased interface area of deposited filaments, providing insight into the mechanisms that lead to the improved properties observed in destructive testing. The supporting powder heat treatment allows the fabrication of parts with complex geometry through material extrusion 3D printing while mitigating the inherent disadvantage of the fabrication process of producing parts with inferior mechanical properties.
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Bargan, Alexandra, Mihaela Dorina Onofrei, Iuliana Stoica, Florica Doroftei, Simona Dunca, and Anca Filimon. "Materials Based on Quaternized Polysulfones with Potential Applications in Biomedical Field: Structure–Properties Relationship." International Journal of Molecular Sciences 23, no. 9 (April 25, 2022): 4721. http://dx.doi.org/10.3390/ijms23094721.
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Starting from the bactericidal properties of functionalized polysulfone (PSFQ) and due to its excellent biocompatibility, biodegradability, and performance in various field, cellulose acetate phthalate (CAP) and polyvinyl alcohol (PVA), as well as their blends (PSFQ/CAP and PSFQ/PVA), have been tested to evaluate their applicative potential in the biomedical field. In this context, because the polymer processing starts from the solution phase, in the first step, the rheological properties were followed in order to assess and control the structural parameters. The surface chemistry analysis, surface properties, and antimicrobial activity of the obtained materials were investigated in order to understand the relationship between the polymers’ structure–surface properties and organization form of materials (fibers and/or films), as important indicators for their future applications. Using the appropriate organization form of the polymers, the surface morphology and performance, including wettability and water permeation, were improved and controlled—these being the desired and needed properties for applications in the biomedical field. Additionally, after antimicrobial activity testing against different bacteria strains, the control of the inhibition mechanism for the analyzed microorganisms was highlighted, making it possible to choose the most efficient polymers/blends and, consequently, the efficiency as biomaterials in targeted applications.
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Bargan, Alexandra, Mihaela Dorina Onofrei, Iuliana Stoica, Florica Doroftei, Simona Dunca, and Anca Filimon. "Materials Based on Quaternized Polysulfones with Potential Applications in Biomedical Field: Structure–Properties Relationship." International Journal of Molecular Sciences 23, no. 9 (April 25, 2022): 4721. http://dx.doi.org/10.3390/ijms23094721.
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Starting from the bactericidal properties of functionalized polysulfone (PSFQ) and due to its excellent biocompatibility, biodegradability, and performance in various field, cellulose acetate phthalate (CAP) and polyvinyl alcohol (PVA), as well as their blends (PSFQ/CAP and PSFQ/PVA), have been tested to evaluate their applicative potential in the biomedical field. In this context, because the polymer processing starts from the solution phase, in the first step, the rheological properties were followed in order to assess and control the structural parameters. The surface chemistry analysis, surface properties, and antimicrobial activity of the obtained materials were investigated in order to understand the relationship between the polymers’ structure–surface properties and organization form of materials (fibers and/or films), as important indicators for their future applications. Using the appropriate organization form of the polymers, the surface morphology and performance, including wettability and water permeation, were improved and controlled—these being the desired and needed properties for applications in the biomedical field. Additionally, after antimicrobial activity testing against different bacteria strains, the control of the inhibition mechanism for the analyzed microorganisms was highlighted, making it possible to choose the most efficient polymers/blends and, consequently, the efficiency as biomaterials in targeted applications.
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Gangavarapu, Pranathi, Shane Foister, and Thomas A. Zawodzinski. "Toward Improved Polymer Electrolyte Membranes in a High Temperature, Low Relative Humidity Environment." ECS Meeting Abstracts MA2022-02, no. 41 (October 9, 2022): 1511. http://dx.doi.org/10.1149/ma2022-02411511mtgabs.
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Previous studies on Polymer Electrolyte Membranes have shown that sulfonated polymers exhibit high thermal stability and mechanical properties. The proton conductivity of the sulfonated polymer is strongly dependent upon the degree of sulfonation, where it increases with increasing degree of sulfonation. Also, some observations suggest that densely packed sulfonate groups confer some advantages in allowing more mobile water and protons in the low water content range. In this study bisphenol-based polymers were modified by adding sulfone-amides to form a ball of sulfonates (BOS). Thin, ductile films of the membrane are fabricated by the solution casting method, which resulted in membranes with a thickness of approximately 50 mm. The synthesized copolymers and membranes are characterized by 1 H NMR, FT-IR, ion exchange capacity, water uptake, specific density and proton conductivity measurements. The water uptake and proton conductivity of the membranes are analyzed to determine the impact of varying degrees of sulfonation and side -chains groups within the modified Bisphenol based membranes. Conductivity was tested over a range of temperatures and relative humidity levels simulating potential operating conditions. Water sorption was tested over a range of relative humidity levels to gain an understanding of how relative humidity affects membrane hydration, which is one of the primary factors determining the rate of proton transport in the membrane. In addition, specific density was also measured as density offers insight into membrane hydration and polymer morphology and allows assessment of the mobility of the charge carriers. By studying membranes in this fashion, their performance can be objectively assessed in a controlled environment prior to testing in PEM fuel cells.
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Klopman, Gilles, Dmitri Ptchelintsev, Manton Frierson, Stephen Pennisi, Kevin Renskers, and Michael Dickens. "Multiple Computer Automated Structure Evaluation Methodology as an Alternative to In Vivo Eye Irritation Testing." Alternatives to Laboratory Animals 21, no. 1 (January 1993): 14–27. http://dx.doi.org/10.1177/026119299302100104.
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The Multiple Computer Automated Structure Evaluation (Multi-CASE) methodology was applied to the semi-quantitative analysis of eye irritation potential of 186 organic chemicals. The resulting expert dictionary of substructural attributes indicates that the following functionalities are linked to eye irritation potential: carboxylate and sulphonate groups in anionic surfactants, phenolic moieties in non-ionic surfactants, amino groups, halogenated and unsaturated structures, anhydrides and epoxides. Ester groups were recognised as having a low irritation potential. The Multi-CASE program successfully predicted a priori the eye irritation potential of: 1) 21 individual chemicals; 2) chemical mixtures such as coconut oil, hydrogenated castor oil, rice bran, eucalyptus oils and potassium alginate; and 3) polymers,’ including polyvinyl alcohols, polyvinyl butyral, polyvinyl pyrrolidone, corn starch and nylon. It was found that the structure of the repeat units together, and not that of the individual monomers, is the best predictor of the eye irritation potential of the corresponding polymers. It appears that the repeat units of polymers dilute out the irritation potential of terminal groups normally expected to contribute significant irritation potential to chemicals of lower molecular weight. The Multi-CASE eye irritation model can be used for: 1) in vitro prescreening for eye irritation potential; and 2) design and modification of chemicals when low eye irritation potential is important.
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Godovalov, A. P., M. S. Stepanov, M. V. Yakovlev, E. E. Kobzarenko, and K. A. Batog. "DETERMINATION OF BIOFILM FORMING ACTIVITY OF MICROORGANISMS ON SYNTHETIC POLYMERIC MATERIALS." Russian Clinical Laboratory Diagnostics 64, no. 12 (December 15, 2019): 758–61. http://dx.doi.org/10.18821/0869-2084-2019-64-12-758-761.
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Microorganisms are able to form biofilms on surfaces of biotic and abiotic nature. In turn, in human biotopes there are optimal conditions for the implementation of biofilm-forming activity. Moreover, in medical practice, polymeric materials are often used for drainage or prosthetics, which can also be successfully colonized by bacteria. However, in laboratory practice, the formation of biofilms is usually evaluated on glass or polystyrene. The purpose of the study is to evaluate the methodological features of studying the biofilm-forming activity of microorganisms on the surface of synthetic polymeric materials. We used strains of Staphylococcus aureus ATCC 25923, Escherichia coli K-12, Candida albicans ATCC 10231, as well as synthetic polymeric materials - DentLight Flow light-curing composite material (nano-hybrid fluid composite; Russia), glass ionomer chemical curing Fuji 1 (Japan), cement for temporary fixation of orthopedic constructions TempBond NE (USA), acrylic, polyurethane and polyvinyl chloride. The formation of biofilms in flat-bottomed ELISA plates in this study was considered as a control group. If the polymer belonged to cold curing materials, sterile flat-bottomed tablets were used, the bottom of which was filled with a thin layer of plastic. After hardening of the plastic, biofilms were formed in the tablets. In the second series of experiments, hot cured materials cut into equal parts 5×5×1 mm in size were placed in the wells of a plate and again used to determine biofilm formation with subsequent coloring. To extract the dye, the pieces were transferred to a new plate to exclude the amount of film biomass formed on the walls of the plate wells. In both cases, cultivation was carried out at 37° C for 24-48 hours. The biomass of the film was stained with fuchsin. Statistical data processing was performed using t-Student criterion. For the threshold level of significance, the value p <0.05 was taken. It is established that the proposed options for determining biofilm forming ability are available and indicative. It was revealed that the same microorganisms have individual biofilm formation indicators for each polymer material. The light curing dental composite and polyvinyl chloride exhibit the more pronounced antiadhesive properties than cements and polyurethane. Up to date, most of the studies of biofilm formation have been carried out using glass or polystyrene, which, as a rule, are not used for the manufacture of prostheses, catheters, drains, etc., which makes it difficult to assess the true film-forming activity of microorganisms. The proposed methodological approaches, especially the second option for preparing testing samples, solve this problem. In general, the proposed approaches to testing biofilm-forming activity on polymers are very simple to implement and generally available. For an adequate study of the biofilms formation, it will be advisable to use polymer materials, directly used in medicine, rather than polystyrene tablets, the material of which is found exclusively in laboratory practice.
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Pilia, Marcello, Teja Guda, and Mark Appleford. "Development of Composite Scaffolds for Load-Bearing Segmental Bone Defects." BioMed Research International 2013 (2013): 1–15. http://dx.doi.org/10.1155/2013/458253.
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The need for a suitable tissue-engineered scaffold that can be used to heal load-bearing segmental bone defects (SBDs) is both immediate and increasing. During the past 30 years, various ceramic and polymer scaffolds have been investigated for this application. More recently, while composite scaffolds built using a combination of ceramics and polymeric materials are being investigated in a greater number, very few products have progressed from laboratory benchtop studies to preclinical testing in animals. This review is based on an exhaustive literature search of various composite scaffolds designed to serve as bone regenerative therapies. We analyzed the benefits and drawbacks of different composite scaffold manufacturing techniques, the properties of commonly used ceramics and polymers, and the properties of currently investigated synthetic composite grafts. To follow, a comprehensive review ofin vivomodels used to test composite scaffolds in SBDs is detailed to serve as a guide to design appropriate translational studies and to identify the challenges that need to be overcome in scaffold design for successful translation. This includes selecting the animal type, determining the anatomical location within the animals, choosing the correct study duration, and finally, an overview of scaffold performance assessment.
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Han, Gangqi, Bing Wang, Mengli Jia, Shuxin Ding, Wenxuan Qiu, Yuxuan Mi, Zhimei Mi, et al. "Optimization and evaluation of resveratrol amorphous solid dispersions with a novel polymeric system." Mathematical Biosciences and Engineering 19, no. 8 (2022): 8019–34. http://dx.doi.org/10.3934/mbe.2022375.
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<abstract> <p>The preparation of amorphous solid dispersions using polymers is a commonly used formulation strategy for enhancing the solubility of poorly water-soluble drugs. However, a single polymer often does not bring significantly enhance the solubility or amorphous stability of a poorly water-soluble drug. We found an application of a unique and novel binary polymeric blend in the preparation of solid dispersions. The main purpose of this study is to optimize and evaluate resveratrol (Res) amorphous solid dispersions with a novel polymeric system of poly (vinyl pyrrolidone) (PVP) and carboxymethyl chitosan (CMCS). The influence of three different release factors, the ratio of CMCS to the polymer mixture (CMCS% = X<sub>1</sub>), the ratio of Res to the polymer mixture (Res% = X<sub>2</sub>) and the surfactant (Tween 80 = X<sub>3</sub>), on the characteristics of released Res at various times (Q<sub>5</sub> and Q<sub>30</sub>) was investigated. The computer optimization and contour plots were used to predict the levels of the independent variables as X<sub>1</sub> = 0.17, X<sub>2</sub> = 0.10 and X<sub>3</sub> = 2.94 for maximized responses of Q<sub>5</sub> and Q<sub>30</sub>. Fourier transform infrared spectroscopy (FTIR) results revealed that each polymer formed hydrogen bonds with Res. The solid performance and physical stability of the optimized ternary dispersions were studied with scanning electron microscopy (SEM), powder X-ray diffraction (XRD), modulated differential scanning calorimetry (MDSC) and dissolution testing. SEM, XRD and MDSC analysis demonstrated that the Res was amorphous, and MDSC showed no evidence of phase separation during storage. Dissolution testing indicated a more than fourfold increase in the apparent solubility of the optimized ternary dispersions, which maintained high solubility after 90 days. In our research, we used CMCS as a new carrier in combination with PVP, which not only improved the <italic>in vitro</italic> dissolution of Res but also had better stability.</p> </abstract>
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Pöstges, Florian, Kevin Kayser, Jan Appelhaus, Marius Monschke, Michael Gütschow, Christian Steinebach, and Karl G. Wagner. "Solubility Enhanced Formulation Approaches to Overcome Oral Delivery Obstacles of PROTACs." Pharmaceutics 15, no. 1 (January 3, 2023): 156. http://dx.doi.org/10.3390/pharmaceutics15010156.
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PROteolysis TArgeting Chimaeras (PROTACs) offer new opportunities in modern medicine by targeting proteins that are undruggable to classic inhibitors. However, due to their hydrophobic structure, PROTACs typically suffer from low solubility, and oral bioavailability remains challenging. At the same time, due to their investigative state, the drug supply is meager, leading to limited possibilities in terms of formulation development. Therefore, we investigated the solubility enhancement employing mini-scale formulations of amorphous solid dispersions (ASDs) and liquisolid formulations of the prototypic PROTAC ARCC-4. Based on preliminary supersaturation testing, HPMCAS (L Grade) and Eudragit® L 100-55 (EL 100-55) were demonstrated to be suitable polymers for supersaturation stabilization of ARCC-4. These two polymers were selected for preparing ASDs via vacuum compression molding (VCM), using drug loads of 10 and 20%, respectively. The ASDs were subsequently characterized with respect to their solid state via differential scanning calorimetry (DSC). Non-sink dissolution testing revealed that the physical mixtures (PMs) did not improve dissolution. At the same time, all ASDs enabled pronounced supersaturation of ARCC-4 without precipitation for the entire dissolution period. In contrast, liquisolid formulations failed in increasing ARCC-4 solubility. Hence, we demonstrated that ASD formation is a promising principle to overcome the low solubility of PROTACs.
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Deshevaya, E. A., M. V. Gusarov, and V. А. Tverskoy. "MORPHOLOGY AND ANTIMICROBIAL PROPERTIES OF THE COMPOSITIONS OF POLYVINYL BUTYRAL AND ETHYLENE PROPYLENE RUBBER WITH AROMATIC ALCOHOLS." Aerospace and Environmental Medicine 56, no. 3 (2022): 54–60. http://dx.doi.org/10.21687/0233-528x-2022-56-3-54-60.
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We carried out testing of film-formation and antimicrobial properties of polymer/aromatic alcohol (AA) compositions. The compositions consisted of AA (phenol, resorcin, pyrocatechol, p-methoxyphenol or 4-hydroxybenzoic acid) with polar hydrophilic polyvinyl butyral (PVB) or nonpolar hydrophobic ethylene propylene rubber (SKEP). The polymers and AAs were tested for solubility in various solvents in order to choose those that would be suitable for preparation of simultaneous polymer/AA solutions and ensuing films. Differential scanning calorimetry and IR spectroscopy were used to determine morphology and structure of SKEP/AA and PVB/AA compositions. Since SKEP does not blend with AAs, these compositions are two-phase systems. In contrast, PVB/AA compositions represent monophase systems. PVB compatibility with AAs is explained by establishment of hydrogen bonds. Both types of composition exhibit film-forming properties. SKEP/AA films are characterized by low rigidity, whereas PVB/AA films demonstrate high rigidity. Both types of composition inhibit growth of mold fungi.
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Siddharatha Dhoppalapudi. "Considerations in the formulation of amorphous solid dispersions by hot melt extrusion." GSC Biological and Pharmaceutical Sciences 21, no. 2 (November 30, 2022): 012–21. http://dx.doi.org/10.30574/gscbps.2022.21.2.0421.
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Hot melt extrusion is one of the most popular techniques for the manufacturing of amorphous solid dispersions (ASDs). Over few decades, it has transitioned from lab scale to commercial scale with various products in the market. The current review aims at summarizing various considerations in the formulation development of ASDs using HME. Various types of ASDs from Type I to Type IV are discussed along with the solid state of drug and polymeric carrier in each type. Also, various polymeric carriers used in ASDs are outlined along with information about their glass transition temperature, melting point, hygroscopicity and regulatory status. There are various mechanisms by which the polymeric carriers stabilize the amorphous form of drug in ASDs. These mechanisms are classified as crystallization inhibition, anti-plasticization, intermolecular interactions, and reduction of molecular mobility. These four mechanisms are discussed along with case studies. Finally, various considerations in the formulation of ASDs like, rationale selection of polymers, process design and optimization and stability testing with respect to formulation of ASDs using hot melt extrusion are discussed. In conclusion, the current state of formulating ASDs using HME are discussed and the need for restructuring the formulation approach is mentioned.
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Hessick, Ethan Robert, Karen Dannemiller, and Perena Gouma. "Development of a Novel Lateral Flow Immunoassay for Detection of Harmful Allergens Found in Dust." ECS Meeting Abstracts MA2022-01, no. 55 (July 7, 2022): 2333. http://dx.doi.org/10.1149/ma2022-01552333mtgabs.
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Prior research has shown that specific allergens from house pests, including mice, dust mites, and cockroaches, can lead to worsened symptoms for asthmatic patients. These allergens can be found in indoor environments where dust collects, such as homes, schools, or hospitals. There currently is a need for an accurate, easy-to-use, inexpensive sensor that is capable of detecting and quantifying the amount of these allergens in samples of dust collected in these indoor environments. This sensor would help lead to treatment of pest problems in affected areas and allow for further study of the interaction between these allergens and health outcomes. To create this biosensor, a lateral flow assay has been developed. The developed system uses novel polymer-based materials created by electrospinning. The polymers used in this work include Cellulose Acetate (CA) and Polyvinylpyrrolidone (PVP). Electrospinning is a process where high voltages are used with a syringe pump to create a Taylor cone that sends a polymer jet onto a collector plate. This polymer jet collects on the collector plate as polymer nanofibers, which after aggregation with other nanofibers become a nanofibrous polymer mat. In our work, electrospun polymers have been functionalized for use in traditional portions of a lateral flow immunoassay testing strip. Antibodies encapsulated using polymer processing techniques, and antibodies immobilized onto electrospun polymer material allow for the traditional sandwich detection method when allergen is present. The sandwich detection method makes use of the binding of two antibodies, at different and non-inhibiting binding sites, to a single allergen to cause an observable and measurable color change when the allergen is present. An illustration of the sandwich detection technique is included as the abstract image. One of the antibodies must be immobilized, and the other must be optically labeled for the sandwich to produce a color change. We also have developed a wicking polymer using electrospinning to act as the backbone for our biosensor strips. This is a novel application of electrospun polymers for wicking, and we have worked to characterize and optimize the wicking properties of this material. The use of electrospinning to create functional polymers, which are biocompatible, inexpensive, and relatively safe, poses advantages over the materials typically used in literature, including nitrocellulose, which is a flammability hazard. This novel wicking material has high potential for future use in lateral flow assays and other biosensing techniques that make use of wicking materials. A collaborative group is working to create a phone application that will use the color produced by the strip when a sample is loaded to determine the amount of allergen in the sample and estimate the severity of the indoor environment’s pest problem. The combination of the optical sensor and phone app will enable quantitative measurement of harmful allergens in the dust sample. This will allow the user to take necessary action to remove pests and dust that is worsening asthma symptoms and related health outcomes. Future work in this project includes working to improve the sensitivity of the color change, which will require signal amplification techniques and analysis of different labeling methods. Additionally, the novel wicking material, allergen detection technique, and phone application could be modified to detect other biomolecules of interest for important health, environmental, or related fields. Figure 1
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YİLMAZ, Cagatay, Hafiz Qasim ALİ, and Mehmet YILDIZ. "Klasik Laminasyon Teorisinin Üç Boyutlu Yazıcı ile Eriyik Yığma Modelleme Yöntemi Kullanılarak Üretilmiş Plastiklere Uygulanması ve Tam Alanlı Yüzey Gerinim Haritalanması." Afyon Kocatepe University Journal of Sciences and Engineering 22, no. 2 (April 30, 2022): 342–52. http://dx.doi.org/10.35414/akufemubid.1018774.
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In this study, five differently oriented sets of 3D-printed tensile samples are produced using the Fused Deposition Method (FDM). Among these five sets, three are used to determine the elastic constant to be used in Classical Lamination Theory (CLT), which is generally used to model fiber-reinforced polymers (FRP). Based on the obtained results, CLT is further applied to the remaining two sets of unreinforced 3D-printed polymer samples where the deposition direction varies in each layer. The stress and strain calculated with CLT are then compared with experimental results obtained through tensile testing. The comparison depicts that experimental and CLT results are in good agreement at lower strain levels. In contrast, the stress calculated with CLT deviates from the experimental result at the higher strain levels.Thereafter, a full-field surface strain mapping is applied by using Digital Image Correlation (DIC) Techniques to reveal the damage progression and failure of Fused Deposition Method 3-D Printed Plastics.
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Hubbard, Roger A. "Human Papillomavirus Testing Methods." Archives of Pathology & Laboratory Medicine 127, no. 8 (August 1, 2003): 940–45. http://dx.doi.org/10.5858/2003-127-940-hptm.
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Abstract Testing for human papillomavirus (HPV) relies exclusively on techniques of molecular biology using nucleic acid probes. Tests for HPV using nucleic acid probes have been commercially available since the late 1980s, but early tests were cumbersome, involving the use of nucleic acid probes labeled with radioactive phosphorus (32P). These early HPV tests did not achieve widespread use because they did not detect all oncogenic HPV genotypes. The current commercial HPV detection kit, Digene's Hybrid Capture 2 kit, detects virtually all high-risk oncogenic HPV types, as well as most low-risk nononcogenic HPV genotypes. The Hybrid Capture 2 test format is a proprietary nucleic acid hybridization signal amplification system owned by Digene Corporation. Virtually all test formats for DNA sequence analysis are amenable to applications intended to detect and perhaps quantify the various HPV genotypes. These methods can involve direct hybridization with complementary DNA probes, such as Southern blotting or in situ hybridization, signal amplification, such as the Hybrid Capture 2 method or target nucleic acid amplification, most notably the polymerase chain reaction (PCR). Polymerase chain reaction has been used for HPV detection, genotyping, and viral load determination. General or consensus primer–mediated PCR assays have enabled screening for a broad spectrum of HPV types in clinical specimens using a single PCR reaction. Following amplification using consensus primers, individual HPV genotypes are identified using a variety of methods. Using consensus primers in a test format known as real-time quantitative PCR (RQ-PCR), it is possible to generate viral load (concentration) data from reaction curves generated by monitoring PCR reaction kinetics in real time.
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Merritt, William, Anne Marie Holter, Sharna Beahm, Connor Gonzalez, Timothy A. Becker, Aaron Tabor, Andrew F. Ducruet, Laura S. Bonsmann, Trevor R. Cotter, and Sergey Frenklakh. "Quantifying the mechanical and histological properties of thrombus analog made from human blood for the creation of synthetic thrombus for thrombectomy device testing." Journal of NeuroInterventional Surgery 10, no. 12 (April 25, 2018): 1168–73. http://dx.doi.org/10.1136/neurintsurg-2017-013675.
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BackgroundUntreated ischemic stroke can lead to severe morbidity and death, and as such, there are numerous endovascular blood-clot removal (thrombectomy) devices approved for human use. Human thrombi types are highly variable and are typically classified in qualitative terms – ‘soft/red,’ ‘hard/white,’ or ‘aged/calcified.’ Quantifying human thrombus properties can accelerate the development of thrombus analogs for the study of thrombectomy outcomes, which are often inconsistent among treated patients.Methods‘Soft’human thrombi were created from blood samples ex vivo (ie, human blood clotted in sample vials) and tested for mechanical properties using a hybrid rheometer material testing system. Synthetic thrombus materials were also mechanically tested and compared with the ‘soft’ human blood clots.ResultsMechanical testing quantified the shear modulus and dynamic (elastic) modulus of volunteer human thrombus samples. This data was used to formulate a synthetic blood clot made from a composite polymer hydrogel of polyacrylamide and alginate (PAAM-Alg). The PAAM-Alg interpenetrating network of covalently and ionically cross-linked polymers had tunable elastic and shear moduli properties and shape memory characteristics.ConclusionsDue to its adjustable properties, PAAM-Alg can be modified to mimic various thrombi classifications. Future studies will include obtaining and quantitatively classifying patient thrombectomy samples and altering the PAAM-Alg to mimic the results for use with in vitro thrombectomy studies.
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Povernov, P. A., L. S. Shibryaeva, L. R. Lusova, and A. A. Popov. "Modern polymer composite materials for bone surgery: Problems and prospects." Fine Chemical Technologies 17, no. 6 (January 24, 2023): 514–36. http://dx.doi.org/10.32362/2410-6593-2022-17-6-514-536.
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Objectives. To discuss the main problems and prospects of creating modern osteoplastic materials based on polymer compositions used for bone surgery.Methods. This review summarizes the research works devoted to the creation of materials used for bone implants and issues involved in their practical testing, as well as analyzes and synthesizes data of scientific articles on the following topics: rationale for the use of biodegradable materials in bone surgery; biodegradation and bioreparation bone graft processes; requirements for degradable polymer composite materials (PCMs) for biomedical applications; overview of polymeric materials suitable for use in implant practice; impact of modifications of the PCM on the structure and biological activity of the material in biological media; effect of exhaust and heat treatment on the molecular structure of polyalkanoates.Results. The most promising biodegradable resorbable materials for reparative bone surgery to date are compared. The requirements for these types of materials are formulated and a rationale for their use is provided that takes into account the advantages over traditional metal and ceramic implants. The features of the kinetics and mechanism of biodegradation of implants in their interaction with the bone biological environment of the body from the moment of implant insertion to complete wound healing are considered. As a result of the analysis, factors that may affect the activity of implant decomposition and methods of adjusting the decomposition rate and mechanical characteristics of the material, such as chemical functionalization, the creation of block copolymers, the inclusion of fibers and mineral fillers in the composite, as well as heat treatment and extraction of the composite at the manufacturing stage, were identified. Among the main factors, the influence of the structure of the composite material on its biological activity during interaction with biological media was evaluated. Of polymer materials, the main attention is paid to the most common biodegradable polymers widely used in medicine: polyhydroxybutyrate (PHB) of microbiological origin, polylactide (PLA) and other polymers based on polylactic acid, polycaprolactone (PCL). The effect of their modification by such additives as hydroxyapatite (HAP), chitin and chitosan, and beta-tricalcium phosphate (β-TCF) is considered. Materials based on PHB are concluded as the most promising due to their complete biodegradability to non-toxic products (carbon dioxide and water) and good biocompatibility. Nevertheless, existing compositions based on PHB are not without disadvantages, which include fragility, low elasticity, unstable behavior under high-temperature exposure during processing, implant molding, sterilization, etc., which requires improvement both in terms of polymer modification and in terms of composition of compositions.Conclusions. The review considers approaches to achieving the properties of materials required for perfect implants. The main requirements for implants are optimization of the time of resorption of the osteoplastic matrix, facilitating the resorption of the osteoplastic matrix synchronized in time with the process of bone regeneration. To achieve these requirements, it is necessary to apply technologies that include modification of polymer composite materials by affecting the chemical composition and structure; introduction of fillers; use of chemical functionalization, orientation extraction, heat treatment. The success of using bone materials based on biodegradable polymers is based on an accurate understanding of the mechanism of action of various components of the implant composition and strict compliance with the tightening regulatory requirements of implantation technology.
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Greiner, Dale L., Joshua C. Doloff, Atieh Sadraei, Shady Farah, Michael A. Brehm, Leonard D. Shultz, Robert Langer, and daniel G. Anderson. "Development of a humanized mouse model for functional testing of biomaterial fibrosis." Journal of Immunology 202, no. 1_Supplement (May 1, 2019): 126.37. http://dx.doi.org/10.4049/jimmunol.202.supp.126.37.
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Abstract Implanted biomedical devices reside within tens of millions of patients in the United States alone, and are involved in millions of new surgeries every year. They comprise a major component of modern medicine and are essential for many clinical applications ranging from hip/knee replacement, tissue repair/reconstruction, controlled release, sensing, and cell transplantation. Limiting therapeutic performance and lifespan, immune-mediated foreign body rejection results in sequestration behind dense layers of fibrotic scar tissue. Deeper understanding of wildtype rodent and non-human primate foreign body responses was leveraged to generate a variant of humanized mice that is capable of recapitulating fibrosis following implantation. Cellular and cytokine responses were also determined with multiple biomaterials—hydrogel alginate and polymers polystyrene and polydimethylsiloxane (PDMS), as well as across multiple implant sites. Innate immune macrophages were verified as essential in the development of fibrosis in this model, and that they were capable of crosstalk with mouse fibroblasts for collagen matrix deposition. Cytokine and cytokine-receptor array analysis confirmed core signaling in the fibrotic cascade. Lastly, high-resolution microscopy coupled with multiplexed antibody-capture analyses revealed spatial resolution of rejection responses. This model allows us to investigate dynamic human immune cell interactions with implantables, and offers a surrogate pre-clinical diagnostic for screening biomaterial immunogenicity.
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Kjellstrand, Per, Eva Lindqvist, and Carin Nilsson-Thorell. "Toxicity Testing of Polymer Materials for Dialysis Equipment: Reconsidering In Vivo Testing." Alternatives to Laboratory Animals 28, no. 3 (May 2000): 495–502. http://dx.doi.org/10.1177/026119290002800307.
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Cozma, Vlad, Irina Rosca, Luminita Radulescu, Cristian Martu, Valentin Nastasa, Cristian-Dragos Varganici, Elena-Laura Ursu, Florica Doroftei, Mariana Pinteala, and Carmen Racles. "Antibacterial Polysiloxane Polymers and Coatings for Cochlear Implants." Molecules 26, no. 16 (August 12, 2021): 4892. http://dx.doi.org/10.3390/molecules26164892.
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Within this study, new materials were synthesized and characterized based on polysiloxane modified with different ratios of N-acetyl-l-cysteine (NAC) and crosslinked via UV-assisted thiol-ene addition, in order to obtain efficient membranes able to resist bacterial adherence and biofilm formation. These membranes were subjected to in vitro testing for microbial adherence against S. pneumoniae using standardized tests. WISTAR rats were implanted for 4 weeks with crosslinked siloxane samples without and with NAC. A set of physical characterization methods was employed to assess the chemical structure and morphological aspects of the new synthetized materials before and after contact with the microbiological medium.
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Li, Roman, Dmitry Psarev, Maria Kiba, and Anton Melnikov. "ACCELERATED FATIGUE TEST METHOD POLYMER MATERIALS." SCIENCE IN THE CENTRAL RUSSIA, no. 3 (June 30, 2022): 92–102. http://dx.doi.org/10.35887/2305-2538-2022-3-92-102.
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The issues of durability of bearing assemblies in car transmissions, which are largely determined by the wear of bearing seats due to fretting corrosion, are considered. It has been established that their restoration with polymeric materials can completely eliminate fretting corrosion, significantly increase the service life of bearing assemblies and reduce the cost of car repairs. The durability of the restored fit depends on the resource of the polymer layer between the mating surfaces of the parts of the bearing assembly, and therefore the study of the endurance of new polymeric materials under cyclic loading is an urgent issue. t was revealed that a common drawback of the known methods of fatigue testing is the limited suitability for specimens of various sizes (scale factor). A review and analysis of fatigue testing methods was carried out and, as a result, the following were selected: the Lokati method, the one-sample method, the Kudryavtsev method, the Kravchenko method, the Shubin method. A new method of accelerated bench tests for the endurance of polymer materials is proposed, which is based on the methods of Shubin and Kravchenko. Initially, the durability of polymer fits under cyclic loading is determined with three specified values of the thickness of the polymer coating. The maximum allowable thickness of the polymer fit should be determined by extrapolation of the graphical dependence until it intersects with the ordinate axis (coating thickness). The method includes calculating and using the original similarity criterion, which will allow using the results of bench tests to determine the maximum allowable thickness of the polymer fit for any type of rolling bearing size. The control experiment confirmed the objectivity and correctness of the new method.
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Dragostin, Ionut, Oana-Maria Dragostin, Andreea Teodora Iacob, Maria Dragan, Carmen Lidia Chitescu, Luminita Confederat, Alexandra-Simona Zamfir, Rodica Tatia, Catalina Daniela Stan, and Carmen Lacramioara Zamfir. "Chitosan Microparticles Loaded with New Non-Cytotoxic Isoniazid Derivatives for the Treatment of Tuberculosis: In Vitro and In Vivo Studies." Polymers 14, no. 12 (June 7, 2022): 2310. http://dx.doi.org/10.3390/polym14122310.
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Lately, in the world of medicine, the use of polymers for the development of innovative therapies seems to be a major concern among researchers. In our case, as a continuation of the research that has been developed so far regarding obtaining new isoniazid (INH) derivatives for tuberculosis treatment, this work aimed to test the ability of the encapsulation method to reduce the toxicity of the drug, isoniazid and its new derivatives. To achieve this goal, the following methods were applied: a structural confirmation of isoniazid derivatives using LC-HRMS/MS; the obtaining of microparticles based on polymeric support; the determination of their loading and biodegradation capacities; in vitro biocompatibility using MTT cell viability assays; and, last but not least, in vivo toxicological screening for the determination of chronic toxicity in laboratory mice, including the performance of a histopathological study and testing for liver enzymes. The results showed a significant reduction in tissue alterations, the disappearance of cell necrosis and microvesicular steatosis areas and lower values of the liver enzymes TGO, TGP and alkaline phosphatase when using encapsulated forms of drugs. In conclusion, the encapsulation of INH and INH derivatives with chitosan had beneficial effects, suggesting a reduction in hepatotoxicity and, therefore, the achievement of the aim of this paper.
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Singh, Jasvinder, Tejinder Kaur, Neetu Singh, and Pulak Mohan Pandey. "Biological and mechanical characterization of biodegradable carbonyl iron powder/polycaprolactone composite material fabricated using three-dimensional printing for cardiovascular stent application." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 234, no. 9 (July 1, 2020): 975–87. http://dx.doi.org/10.1177/0954411920936055.
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Biological and mechanical properties of biodegradable polymeric composite materials are strongly influenced by the choice of appropriate reinforcement in the polymer matrix. Non-compatibility of material in the vascular system could obstruct the way of the biological fluids. The concept of development of polymeric composite material for vascular implants is to provide enough support to the vessel and to restore the vessel in the natural state after degradation. In this research, the polycaprolactone composite materials (carbonyl iron powder/polycaprolactone) were developed by reinforcement of the 0%–2% of carbonyl iron powder using the solvent cast three-dimensional printing technique. The physicochemical properties of developed composites were characterized in conjunction with mechanical and biological properties. The mechanical characterizations were assessed by uniaxial tensile testing as well as flexibility testing. The results of mechanical testing assured that carbonyl iron powder/polycaprolactone composites have shown desirable properties for vascular implants. Besides the mechanical characterization, in vitro biological investigations of carbonyl iron powder/polycaprolactone were done for analyzing blood compatibility and cytocompatibility. The results revealed that the materials developed were biocompatible, less hemolytic, and having non-thrombogenic properties indicating the promising applications in the field of cardiovascular applications.
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Padule, Komal, Sonali Shinde, Sohan Chitlange, Prabhanjan Giram, and Dheeraj Nagore. "The Advancement of Herbal-Based Nanomedicine for Hair." Cosmetics 9, no. 6 (November 11, 2022): 118. http://dx.doi.org/10.3390/cosmetics9060118.
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Polymer, lipid, and natural protein-based hair care nanocarriers are in preclinical testing. Nanomedicine has enhanced therapeutic efficacy and decreased side effects. This review examines herbal nanomedicine for hair care. We also reviewed the hair cycle, its morphology, and the mechanisms of herbal-based medicine that regulate the hair cycle to treat hair loss. Nano-formulations have better solubility, permeability, therapeutic efficacy, and prolonged distribution than standard herbal medicines. This review also discussed the nanotechnology barrier and nano formulations for hair loss and growth and includes a recent herbal nanomedicine study. Researchers interested in using herbs to treat hair problems and clinically translating hair care products may find the results presented significant.
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Шакиров, Р. Ф., М. Э. Вальяров, В. А. Ефимов, А. Р. Насыбуллин, Р. В. Фархутдинов, and Т. М. Ишкаев. "SIMULATION OF A SENSOR BASED ON A STRIP BRAGG MICROWAVE STRUCTURE FOR CONTROL OF THE DEGREE OF POLYMERIZATION OF COMPOSITES." Южно-Сибирский научный вестник, no. 5(45) (October 31, 2022): 3–8. http://dx.doi.org/10.25699/sssb.2022.45.5.026.
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Статья посвящена созданию компьютерной модели полоскового СВЧ датчика для определения диэлектрических параметров композитных материалов. Актуальность темы обусловлена широким распространением полимерных материалов в настоящее время. Они широко применяются в аэрокосмических конструкциях, судостроении, автомобилестроении, для создания различных резервуаров и в медицине. Целью работы является создание модели датчика, с помощью которого можно проводить неразрушающие исследования композитного материала во время его полимеризации. В результате была получена модель датчика с достаточной чувствительностью для контроля степени полимеризации композитов. Данное устройство позволит проводить непрерывный неразрушающий контроль полимеризации полимеров. The article is devoted to the creation of a computer model of a strip microwave sensor for determining the dielectric parameters of composite materials. The relevance of the topic is due to the widespread use of polymeric materials at the present time. They are widely used in aerospace structures, shipbuilding, automotive, to create various tanks and in medicine. The aim of the work is to create a sensor model that can be used to conduct non-destructive studies of a composite material during its polymerization. As a result, a sensor model with sufficient sensitivity was obtained to control the degree of polymerization of composites. This device will allow continuous non-destructive testing of polymerization of polymers.
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Siavash Moakhar, Roozbeh, Carolina del Real Mata, Houda Shafique, Mahsa Jalali, Justin de Vries, Julia Strauss, Tamer Abdel Fatah, et al. "(Digital Presentation) Biomimic Nanotemplating Assay Based on Molecularly Imprinted Polymers for the Impedimetric Detection of Sars-Cov-2 and Influenza A Spike Proteins in Untreated Saliva." ECS Meeting Abstracts MA2022-02, no. 63 (October 9, 2022): 2446. http://dx.doi.org/10.1149/ma2022-02632446mtgabs.
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With the continuously fluctuating incidence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), critical gaps in the field of rapid diagnostic testing have been exposed, particularly in the diagnosis of viral respiratory infections. Current gold standard methods rely on real time quantitative polymerase chain reaction (RT-qPCR) for the detection of viral nucleic acids, but these tests are challenged with long turnaround times, costly centralized laboratory equipment and the need for trained personnel to execute the protocols. With the growing number of emerging variants that can evade both immune responses and inoculation, addressing current testing challenges is critical to manage the spread of viral infections. Here, we propose the design of a novel assay based on our previously studied gold nano/micro islands (NMIs) as a core for the fabrication of an ultrathin molecularly imprinted polymer (MIP) for the impedimetric detection of SARS-CoV-2 and Influenza A spike proteins (SPs) in untreated saliva within 10 minutes. The proposed electrofabrication protocol is rapidly adaptable to a diverse repertoire of protein biomarkers; in this work, we demonstrate the impedimetric detection of the SARS-CoV-2 original strain, Alpha B.1.1.7, Delta B.1.617.2 and Omicron B.1.1.529 variant SP, as well as the Influenza A SP within physiologically relevant ranges and at a low limit of detection to enable the diagnosis of acute infections. Validation was performed at two unique test sites with 51 SARS-CoV-2 patient samples to demonstrate an overall 100% sensitivity and 100% specificity of the NMIs/MIPs assay. Robust quantification of the electrochemical assay was confirmed against RT-qPCR, which effectively enabled statistically significant (p < .0005) viral load quantification on a rapid, miniaturized, and ultrasensitive platform. This novel technology presents the development of a quantitative and versatile electrochemical assay with the potential for the rapid detection of current and future viral respiratory infections, which can guide future electrochemical clinical and commercial point-of-care testing platforms.
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Ramirez-Vazquez, Isaias, Fermin Pascual Espino-Cortes, and Carlos Gómez-Yáñez. "Direct Current Inclined Plane Testing on Silicone Rubber Composites Reinforced with Silica Nano Particles." Journal of Nano Research 71 (January 25, 2022): 135–49. http://dx.doi.org/10.4028/www.scientific.net/jnanor.71.135.
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Polymer insulators traditionally used in HVAC (High Voltage Alternating Current) are used in HVDC (High Voltage Direct Current) transmission lines. For these polymer insulators, silicone insulating rubber, based on Polydimethylsiloxane (PDMS), is used in industry to manufacture high voltage insulators for power lines. Silicone rubber material ages due to pollution and environmental factors such as UV (ultraviolet light), rain, and temperature. Moreover, no international standard is available to standardize its functional characteristics to ensure its best performance in HVDC regime. Standards usually define the testing procedures to measure the resistance of the materials to these conditions. One of the tests used to evaluate the performance in AC (alternating current) of the housing material of polymeric insulators is the inclined plane test (IPT). This test has the purpose of assessing the tracking and erosion resistance of housing materials. However, for the IPT, no consensus is reached yet for this testing in Direct Current (DC) voltage. In addition, there are no indications whether the formulations that have been successfully used for HVAC work fine; also, in HVDC regime, or not. In this paper, an investigation of the tracking and erosion resistance under positive DC IPT is presented. In this way, the study was carried out on skirts of an HVAC commercial insulator and samples of a new outstanding composite silicone rubber formulation filled with micro and nano particles. The results show that HVAC silicone rubber formulations could not be suitable for HVDC applications under highly polluted conditions. In the case of the new enhanced composite, it is shown how nano particles used in this material significantly enhance the performance during DC tracking and erosion testing well above other materials tested in previous works. Also, thermogravimetric analysis (TGA) of the composites is used to correlate thermal stability with the DC IPT performance.
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ABDEL-KAREEM, OMAR. "Evaluating the Combined Efficacy of Polymers with Fungicides for Protection of Museum Textiles against Fungal Deterioration in Egypt." Polish Journal of Microbiology 59, no. 4 (2010): 271–80. http://dx.doi.org/10.33073/pjm-2010-041.
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Fungal deterioration is one of the highest risk factors for damage of historical textile objects in Egypt. This paper represents both a study case about the fungal microflora deteriorating historical textiles in the Egyptian Museum and the Coptic museum in Cairo, and evaluation of the efficacy of several combinations of polymers with fungicides for the reinforcement of textiles and their prevention against fungal deterioration. Both cotton swab technique and biodeteriorated textile part technique were used for isolation of fungi from historical textile objects. The plate method with the manual key was used for identification of fungi. The results show that the most dominant fungi isolated from the tested textile samples belong to Alternaria, Aspergillus, Chaetomium, Penicillium and Trichoderma species. Microbiological testing was used for evaluating the usefulness of the suggested conservation materials (polymers combined with fungicides) in prevention of the fungal deterioration of ancient Egyptian textiles. Textile samples were treated with 4 selected polymers combined with two selected fungicides. Untreated and treated textile samples were deteriorated by 3 selected active fungal strains isolated from ancient Egyptian textiles. This study reports that most of the tested polymers combined with the tested fungicides prevented the fungal deterioration of textiles. Treatment of ancient textiles by suggested polymers combined with the suggested fungicides not only reinforces these textiles, but also prevents fungal deterioration and increases the durability of these textiles. The tested polymers without fungicides reduce the fungal deterioration of textiles but do not prevent it completely.
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Strohbach, Anne, Friedemann Maess, Katharina Wulf, Svea Petersen, Niels Grabow, Klaus-Peter Schmitz, Stephan B. Felix, and Raila Busch. "The Role of Biodegradable Poly-(L-lactide)-Based Polymers in Blood Cell Activation and Platelet-Monocyte Interaction." International Journal of Molecular Sciences 22, no. 12 (June 13, 2021): 6340. http://dx.doi.org/10.3390/ijms22126340.
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The main purpose of new stent technologies is to overcome unfavorable material-related incompatibilities by producing bio- and hemo-compatible polymers with anti-inflammatory and anti-thrombogenic properties. In this context, wettability is an important surface property, which has a major impact on the biological response of blood cells. However, the influence of local hemodynamic changes also influences blood cell activation. Therefore, we investigated biodegradable polymers with different wettability to identify possible aspects for a better prediction of blood compatibility. We applied shear rates of 100 s−1 and 1500 s−1 and assessed platelet and monocyte activation as well as the formation of CD62P+ monocyte-bound platelets via flow cytometry. Aggregation of circulating platelets induced by collagen was assessed by light transmission aggregometry. Via live cell imaging, leukocytes were tracked on biomaterial surfaces to assess their average velocity. Monocyte adhesion on biomaterials was determined by fluorescence microscopy. In response to low shear rates of 100 s−1, activation of circulating platelets and monocytes as well as the formation of CD62P+ monocyte-bound platelets corresponded to the wettability of the underlying material with the most favorable conditions on more hydrophilic surfaces. Under high shear rates, however, blood compatibility cannot only be predicted by the concept of wettability. We assume that the mechanisms of blood cell-polymer interactions do not allow for a rule-of-thumb prediction of the blood compatibility of a material, which makes extensive in vitro testing mandatory.
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Floré, Katelijne M. J., and Joris R. Delanghe. "Analytical Interferences in Point-of-Care Testing Glucometers by Icodextrin and its Metabolites: An Overview." Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis 29, no. 4 (July 2009): 377–83. http://dx.doi.org/10.1177/089686080902900403.
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Current point-of-care testing (POCT) glucometers are based on various test principles. Two major method groups dominate the market: glucose oxidase-based systems and glucose dehydrogenase-based systems using pyrroloquinoline quinone (GDH-PQQ) as a cofactor. The GDH-PQQ-based glucometers are replacing the older glucose oxidase-based systems because of their lower sensitivity for oxygen. On the other hand, the GDH-PQQ test method results in falsely elevated blood glucose levels in peritoneal dialysis patients receiving solutions containing icodextrin ( e.g., Extraneal; Baxter, Brussels, Belgium). Icodextrin is metabolized in the systemic circulation into different glucose polymers, but mainly maltose, which interferes with the GDH-PQQ-based method. Clinicians should be aware of this analytical interference. The POCT glucometers based on the GDH-PQQ method should preferably not be used in this high-risk population and POCT glucose results inconsistent with clinical suspicion of hypoglycemic coma should be retested with another testing system.
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Ophale, Shivhar, Shashiprabha L. Gupta, and Arati Dubewar. "Tamra Bhasma preparation by two methods and evaluating their effect on the Liver Function test pre-clinically." International Journal of Ayurvedic Medicine 13, no. 2 (July 8, 2022): 377–83. http://dx.doi.org/10.47552/ijam.v13i2.2549.
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Rasashastra is an important branch of Indian System of Medicine, which deals with the pharmaceutical processes, such as preparations of Bhasmas, Pistis, Kharaliya Rasayanas, Druti, Kupipakva Rasayanas, Parpati, Pottali. It is a well-known fact in the Ayurveda world that Bhasmas are highly efficacious and there are so many preparations of Tamra that are indicated for different ailments. Medicines (kalpas) mentioned in Rasa shastra are used freely in clinical practice by Ayurveda physicians after trial and testing. Now Ayurveda is accepted by world. Due to globalization, it is necessary to prove the Ayurveda drugs with modern parameters. So it can be utilized worldwide to get health. Hence the work taken here is preparation of Tamra Bhasma by two different methods and evaluating their effect on the Liver Function test pre-clinically. Tamra Bhasma preparation by two methods was chosen to compare the difference between direct heat and indirect heat method. Preparation with indirect heat by using sunlight method and with direct heat method resulted into bhasma. Biochemical and Histopathological changes in Liver were observed. Liver function assessment parameters namely serum Bilirubin, SGOT, SGPT, total protein were taken for biochemical evaluation. Also histopathology of Liver and Kidney was taken for study in support of biochemistry. The results were compared with standard drug Silymarine.
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Challenor, Rachel, Nick Theobald, Sue Pinsent, and Helen Mullan. "The management of first episode genital herpes in genitourinary medicine clinics: a national audit in 2006." International Journal of STD & AIDS 18, no. 10 (October 1, 2007): 711–14. http://dx.doi.org/10.1258/095646207782193740.
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A national audit of the management of first episode genital herpes (GH) was undertaken by non-consultant career grade doctors working in genitourinary (GU) medicine clinics in the United Kingdom. In total, 1620 data collection forms were completed (794 men and 826 women). Virus culture is the main detection method (1150, 71%), although polymerase chain reaction (PCR) use is increasing (442, 28%). PCR was significantly associated ( P<0.0001) with fewer negative isolates (29/442, 6.6%) compared with virus culture (174/1150, 15%). Herpes simplex virus type 1 was isolated in 552 cases (46%). For 243 cases (15%), there was no evidence of counselling about GH. A total of 1355 (84%) were screened for other sexually transmitted infections. Serological testing for syphilis was undertaken in 72%. GU medicine clinics are managing first episode GH as broadly outlined in the guidelines. Areas identified for improvement are to increase counselling/written information/testing for syphilis towards 100%.