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Artykuły w czasopismach na temat „Medicinal chemistry-Polystyrene”
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Rokhum, Lalthazuala, i Ghanashyam Bez. "Recent Application of Polystyrene-supported Triphenylphosphine in Solid-Phase Organic Synthesis". Current Organic Chemistry 23, nr 6 (4.07.2019): 643–78. http://dx.doi.org/10.2174/1385272822666181026115752.
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Recent years have witnessed a fast development of solid phase synthetic pathways, a variety of solid-supported reagent and its applications in diverse synthetic strategies and pharmaceutical applicability’s. Polymer-supported triphenylphosphine is getting a lot of applications owing to the speed and simplicity in the process. Furthermore, ease of recyclability and reuse of polymer-supported triphenylphosphine added its advantages. This review covers a wide range of useful organic transformations which are accomplished using cross-linked polystyrene-supported triphenylphosphine with the aim of giving renewed interest in the field of organic and medicinal-combinatorial chemistry.
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Carlton, Robert A., Edward Orton, Charles E. Lyman i James E. Roberts. "Qualitative Analysis of Solid Phase Synthesis Reaction Products by X-ray Spectrometry". Microscopy and Microanalysis 3, nr 6 (listopad 1997): 520–29. http://dx.doi.org/10.1017/s1431927697970409.
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Abstract: A novel method for the synthesis of polypeptides using polystyrene/divinylbenzene copolymers as solid supports has drawn the attention of medicinal, pharmaceutical, and agricultural chemists because of its utility in combinatorial chemistry and parallel synthesis. In this method, arrays of solid-phase organic synthesis experiments are conducted simultaneously thereby enabling the preparation of large numbers of novel compounds over a short time period. The analysis of organic compounds attached to polymer supports presents unique challenges to chemists. This study presents some results of the application of energy-dispersive X-ray spectrometry (EDS) in the environmental scanning electron microscope (ESEM) to this problem. EDS in the ESEM has the advantages of minimal sample size, speed, and simplicity because the analyses are performed without special specimen preparation. The progress of a two-step synthetic transformation was followed using EDS-ESEM by the presence of a sulfur peak in the first synthetic step and by a bromine peak in the second step. The synthetic products were also evaluated by infrared spectroscopy and by elemental analysis (ion chromatography). The agreement of the qualitative analysis among all three techniques was good. Analysis by EDS-ESEM not only complements current analytical techniques in solid phase synthesis; it also provides insight into the details of the synthetic transformation.
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Li, Jin, Yajun Zheng, Wei Mi, Theoneste Muyizere i Zhiping Zhang. "Polystyrene-impregnated paper substrates for direct mass spectrometric analysis of proteins and peptides in complex matrices". Analytical Methods 10, nr 24 (2018): 2803–11. http://dx.doi.org/10.1039/c8ay01081a.
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Li, Yandan, Miao Li, Zhen Li, Lei Yang i Xiang Liu. "Effects of particle size and solution chemistry on Triclosan sorption on polystyrene microplastic". Chemosphere 231 (wrzesień 2019): 308–14. http://dx.doi.org/10.1016/j.chemosphere.2019.05.116.
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Krueger, Martin C., Bettina Seiwert, Andrea Prager, Shangwei Zhang, Bernd Abel, Hauke Harms i Dietmar Schlosser. "Degradation of polystyrene and selected analogues by biological Fenton chemistry approaches: Opportunities and limitations". Chemosphere 173 (kwiecień 2017): 520–28. http://dx.doi.org/10.1016/j.chemosphere.2017.01.089.
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Li, Qiongfang, Bo Zhang, Naresh Kasoju, Jinmin Ma, Aidong Yang, Zhanfeng Cui, Hui Wang i Hua Ye. "Differential and Interactive Effects of Substrate Topography and Chemistry on Human Mesenchymal Stem Cell Gene Expression". International Journal of Molecular Sciences 19, nr 8 (9.08.2018): 2344. http://dx.doi.org/10.3390/ijms19082344.
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Variations in substrate chemistry and the micro-structure were shown to have a significant effect on the biology of human mesenchymal stromal cells (hMSCs). This occurs when differences in the surface properties indirectly modulate pathways within numerous signaling networks that control cell fate. To understand how the surface features affect hMSC gene expression, we performed RNA-sequencing analysis of bone marrow-derived hMSCs cultured on tissue culture-treated polystyrene (TCP) and poly(l-lactide) (PLLA) based substrates of differing topography (Fl: flat and Fs: fibrous) and chemistry (Pr: pristine and Am: aminated). Whilst 80% of gene expression remained similar for cells cultured on test substrates, the analysis of differentially expressed genes (DEGs) revealed that surface topography significantly altered gene expression more than surface chemistry. The Fl and Fs topologies introduced opposite directional alternations in gene expression when compared to TCP control. In addition, the effect of chemical treatment interacted with that of topography in a synergistic manner with the Pr samples promoting more DEGs than Am samples in all gene ontology function groups. These findings not only highlight the significance of the culture surface on regulating the overall gene expression profile but also provide novel insights into cell-material interactions that could help further design the next-generation biomaterials to facilitate hMSC applications. At the same time, further studies are required to investigate whether or not the observations noted correlate with subsequent protein expression and functionality of cells.
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Holdcroft, Steven, Ben-Zhong Tang i James E. Guillet. "Two-photon chemistry: facile synthesis of naphthalene- and anthracene-labelled polystyrene by photolysis of aromatic esters". Journal of the Chemical Society, Chemical Communications, nr 5 (1991): 280. http://dx.doi.org/10.1039/c39910000280.
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Van, Bing. "The Properties of Resin Supports and Their Effects on Solid Phase Organic Synthesis". Combinatorial Chemistry & High Throughput Screening 1, nr 4 (grudzień 1997): 215–29. http://dx.doi.org/10.2174/1386207301666220125213328.
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Solvated resin supports are important carriers for solid-phase organic synthesis in combinatorial chemistry and high-throughput parallel synthesis. The physical properties of resin, resin swelling and dynamic solvation, effects of solvated supports on synthesis, kinetics, site interaction, and product purity are reviewed. Selective solvation of resin alters the local reactivity and accessibility of the bound substrate and the mobility of the entrapped reagent. Resin solvation changes during the course of the reaction when the attached substrate changes its polarity or other physicochemical properties. Selective adsorption determines the reaction kinetics and the action of a phase-transfer catalyst further improves the reaction on resin. Sites interact with each other in 1% DVB polystyrene resins to varying degrees depending on solvent, resin, and reactivity of the pendant groups. Total site isolation seems only achievable by controlling several factors simultaneously such as lower loading and steric hindrance. Through the proper selection of resin and solvent, alternating solvents to accommodate dynamic solvation of the resin, optimization of kinetics when changing solid supports and a careful control of resin impurities, solid-phase organic synthesis can lead to high quality combinatorial libraries.
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Abdulkareem, Asma, Aya E. Abusrafa, Sifani Zavahir, Salma Habib, Patrik Sobolčiak, Marian Lehocky, Hana Pištěková, Petr Humpolíček i Anton Popelka. "Novel Slippery Liquid-Infused Porous Surfaces (SLIPS) Based on Electrospun Polydimethylsiloxane/Polystyrene Fibrous Structures Infused with Natural Blackseed Oil". International Journal of Molecular Sciences 23, nr 7 (27.03.2022): 3682. http://dx.doi.org/10.3390/ijms23073682.
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Hydrophobic fibrous slippery liquid-infused porous surfaces (SLIPS) were fabricated by electrospinning polydimethylsiloxane (PDMS) and polystyrene (PS) as a carrier polymer on plasma-treated polyethylene (PE) and polyurethane (PU) substrates. Subsequent infusion of blackseed oil (BSO) into the porous structures was applied for the preparation of the SLIPS. SLIPS with infused lubricants can act as a repellency layer and play an important role in the prevention of biofilm formation. The effect of polymer solutions used in the electrospinning process was investigated to obtain well-defined hydrophobic fibrous structures. The surface properties were analyzed through various optical, macroscopic and spectroscopic techniques. A comprehensive investigation of the surface chemistry, surface morphology/topography, and mechanical properties was carried out on selected samples at optimized conditions. The electrospun fibers prepared using a mixture of PDMS/PS in the ratio of 1:1:10 (g/g/mL) using tetrahydrofuran (THF) solvent showed the best results in terms of fiber uniformity. The subsequent infusion of BSO into the fabricated PDMS/PS fiber mats exhibited slippery behavior regarding water droplets. Moreover, prepared SLIPS exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli bacterium strains.
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Vasil’eva, Irina, Olga Morozova, Galina Shumakovich i Alexander Yaropolov. "Betaine-Based Deep Eutectic Solvent as a New Media for Laccase-Catalyzed Template-Guided Polymerization/Copolymerization of Aniline and 3-Aminobenzoic Acid". International Journal of Molecular Sciences 23, nr 19 (27.09.2022): 11409. http://dx.doi.org/10.3390/ijms231911409.
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Deep eutectic solvents (DESs) can compensate for some of the major drawbacks of traditional organic solvents and ionic liquids and meet all requirements of green chemistry. However, the potential of their use as a medium for biocatalytic reactions has not been adequately studied. In this work we used the DES betaine-glycerol with a molar ratio of 1:2 as co-solvent for enzymatic template-guided polymerization/copolymerization of aniline (ANI) and 3-aminobenzoic acid (3ABA). The laccase from the basidial fungus Trametes hirsuta and air oxygen served as catalyst and oxidant, respectively. Sodium polystyrene sulfonate (PSS) was used as template. Interpolyelectrolyte complexes of homopolymers polyaniline (PANI) and poly(3-aminobenzoic acid) (P3ABA) and copolymer poly(aniline-co-3-aminobenzoic acid) (P(ANI-3ABA)) were prepared and their physico-chemical properties were studied by UV-Vis and FTIR spectroscopy and cyclic voltammetry. According to the results obtained by atomic force microscopy, PANI/PSS had a granular shape, P(ANI-3ABA)/PSS had a spherical shape and P3ABA/PSS had a spindle-like shape. The copolymer showed a greater antimicrobial activity against Escherichia coli and Staphylcocus aureus as compared with the homopolymers. The minimal inhibitory concentration of the P(ANI-3ABA)/PSS against the gram-positive bacterium S. aureus was 0.125 mg mL−1.
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Slepička, Petr, Silvie Rimpelová, Vladimíra Svobodová Pavlíčková, Nikola Slepičková Kasálková, Klaudia Hurtuková, Dominik Fajstavr i Václav Švorčík. "Mammalian Cell Interaction with Periodic Surface Nanostructures". International Journal of Molecular Sciences 23, nr 9 (23.04.2022): 4676. http://dx.doi.org/10.3390/ijms23094676.
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Here, we report on the nanopatterning of different aromatic polymer substrates achieved by KrF excimer laser treatment. The conditions for the construction of the laser-induced periodic surface structures, the so-called LIPSS pattern, were established by optimized laser fluence and a number of pulses. The polymer substrates were polyethylene naphthalate (PEN), polyethersulfone (PES), and polystyrene (PS), which were chosen since they are thermally, chemically, and mechanically resistant polymers with high absorption coefficients at the excimer laser wavelength. The surface morphology of the treated substrates was investigated by atomic force microscopy and scanning electron microscopy, and the roughness and effective surface area on the modified samples were determined. Elemental concentration was characterized by energy-dispersive (EDX) analysis, surface chemistry was determined with X-ray photoelectron spectroscopy (XPS). The samples with the formation of LIPSS induced by 10 mJ·cm−2 with 1000, 3000, and 6000 pulses were used for subsequent in vitro cytocompatibility tests using human cells from osteosarcoma (U-2 OS). The LIPSS pattern and its ability of significant cell guidance were confirmed for some of the studied samples. Cell morphology, adhesion, and proliferation were evaluated. The results strongly contribute to the development of novel applications using nanopatterned polymers, e.g., in tissue engineering, cell analysis or in combination with metallization for sensor construction.
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Hirama, Hirotada, Ryutaro Otahara, Shinya Kano, Masanori Hayase i Harutaka Mekaru. "Characterization of Nanoparticle Adsorption on Polydimethylsiloxane-Based Microchannels". Sensors 21, nr 6 (11.03.2021): 1978. http://dx.doi.org/10.3390/s21061978.
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Nanoparticles (NPs) are used in various medicinal applications. Exosomes, bio-derived NPs, are promising biomarkers obtained through separation and concentration from body fluids. Polydimethylsiloxane (PDMS)-based microchannels are well-suited for precise handling of NPs, offering benefits such as high gas permeability and low cytotoxicity. However, the large specific surface area of NPs may result in nonspecific adsorption on the device substrate and thus cause sample loss. Therefore, an understanding of NP adsorption on microchannels is important for the operation of microfluidic devices used for NP handling. Herein, we characterized NP adsorption on PDMS-based substrates and microchannels by atomic force microscopy to correlate NP adsorptivity with the electrostatic interactions associated with NP and dispersion medium properties. When polystyrene NP dispersions were introduced into PDMS-based microchannels at a constant flow rate, the number of adsorbed NPs decreased with decreasing NP and microchannel zeta potentials (i.e., with increasing pH), which suggested that the electrostatic interaction between the microchannel and NPs enhanced their repulsion. When exosome dispersions were introduced into PDMS-based microchannels with different wettabilities at constant flow rates, exosome adsorption was dominated by electrostatic interactions. The findings obtained should facilitate the preconcentration, separation, and sensing of NPs by PDMS-based microfluidic devices.
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Krueger, Martin C., Ulrike Hofmann, Monika Moeder i Dietmar Schlosser. "Potential of Wood-Rotting Fungi to Attack Polystyrene Sulfonate and Its Depolymerisation by Gloeophyllum trabeum via Hydroquinone-Driven Fenton Chemistry". PLOS ONE 10, nr 7 (6.07.2015): e0131773. http://dx.doi.org/10.1371/journal.pone.0131773.
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Masetto, Thomas, Kai Matzenbach, Thomas Reuschel, Sebastian-Alexander Tölke, Klaus Schneider, Lea Marie Esser, Marco Reinhart, Laura Bindila, Christoph Peter i Matthias Grimmler. "Comprehensive Comparison of the Capacity of Functionalized Sepharose, Magnetic Core, and Polystyrene Nanoparticles to Immuno-Precipitate Procalcitonin from Human Material for the Subsequent Quantification by LC-MS/MS". International Journal of Molecular Sciences 24, nr 13 (30.06.2023): 10963. http://dx.doi.org/10.3390/ijms241310963.
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Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. The fast and accurate diagnosis of sepsis by procalcitonin (PCT) has emerged as an essential tool in clinical medicine. Although in use in the clinical laboratory for a long time, PCT quantification has not yet been standardized. The International Federation of Clinical Chemistry working group on the standardization of PCT (IFCC-WG PCT) aims to provide an LC-MS/MS-based reference method as well as the highest metrological order reference material to address this diagnostic need. Here, we present the systematic evaluation of the efficiency of an immuno-enrichment method, based on functionalized Sepharose, magnetic-core, or polystyrene (latex) nano-particles, to quantitatively precipitate PCT from different human sample materials. This method may be utilized for both mass spectrometric and proteomic purposes. In summary, only magnetic-core nano-particles functionalized by polyclonal PCT antibodies can fulfil the necessary requirements of the international standardization of PCT. An optimized method proved significant benefits in quantitative and specific precipitation as well as in the subsequent LC-MS/MS detection of PCT in human serum samples or HeLa cell extract. Based on this finding, further attempts of the PCT standardization process will utilize a magnetic core-derived immuno-enrichment step, combined with subsequent quantitative LC-MS/MS detection.
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Shim, Na Young, i Jung Sun Heo. "Performance of the Polydopamine-Graphene Oxide Composite Substrate in the Osteogenic Differentiation of Mouse Embryonic Stem Cells". International Journal of Molecular Sciences 22, nr 14 (7.07.2021): 7323. http://dx.doi.org/10.3390/ijms22147323.
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Graphene oxide (GO) is a biocompatible material considered a favorable stem cell culture substrate. In this study, GO was modified with polydopamine (PDA) to facilitate depositing GO onto a tissue culture polystyrene (PT) surface, and the osteogenic performance of the PDA/GO composite in pluripotent embryonic stem cells (ESCs) was investigated. The surface chemistry of the PDA/GO-coated PT surface was analyzed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). A high cell viability of ESCs cultured on the PDA/GO composite-coated surface was initially ensured. Then, the osteogenic differentiation of the ESCs in response to the PDA/GO substrate was assessed by alkaline phosphatase (ALP) activity, intracellular calcium levels, matrix mineralization assay, and evaluation of the mRNA and protein levels of osteogenic factors. The culture of ESCs on the PDA/GO substrate presented higher osteogenic potency than that on the uncoated control surface. ESCs cultured on the PDA/GO substrate expressed significantly higher levels of integrin α5 and β1, as well as bone morphogenetic protein receptor (BMPR) types I and II, compared with the control groups. The phosphorylation of extracellular signal-regulated kinase (ERK)1/2, p38, and c-Jun-N-terminal kinase (JNK) mitogen-activated protein kinases (MAPKs) was observed in ESCs culture on the PDA/GO substrate. Moreover, BMP signal transduction by SMAD1/5/8 phosphorylation was increased more in cells on PDA/GO than in the control. The nuclear translocation of SMAD1/5/8 in cells was also processed in response to the PDA/GO substrate. Blocking activation of the integrin α5/β1, MAPK, or SMAD signaling pathways downregulated the PDA/GO-induced osteogenic differentiation of ESCs. These results suggest that the PDA/GO composite stimulates the osteogenic differentiation of ESCs via the integrin α5/β1, MAPK, and BMPR/SMAD signaling pathways.
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Cosnier, Serge, Paulo Henrique Buzzetti, Yannig Nedellec, Monica Brachi, Karine Gorgy, Chantal Gondran, Dan Shan i Redouane Borsali. "(Keynote) Bioelectrocatalytic Systems Based on Microcapsules, Glyconanoparticles and Microcavities". ECS Meeting Abstracts MA2022-01, nr 49 (7.07.2022): 2079. http://dx.doi.org/10.1149/ma2022-01492079mtgabs.
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For four decades, the functionalization of electrodes by biomaterials based on electrogenerated polymers, carbon nanotubes and / or nano-objects, was widely used in the field of analytical chemistry and energy conversion. Recently, we redesigned enzymatic bioelectrodes in order to produce original objects. An innovative concept of reagentless biosensors based on enzymatic reduction of oxygen was developed by trapping and releasing the substrate of the enzyme (catechol) from the structure of the biosensor. A polyurethane support modified by two perforated microcapsules filled with catechol was easily transformed into a bioelectrode by the successive deposition of multiwalled carbon nanotubes and a mixture of laponite clay and tyrosinase enzyme [1]. On the other hand, the development of glyconanoparticles resulting from the self-assembly of block copolymers composed of polystyrene and cyclodextrin as an inclusion site will be reported. These glyconanoparticles, which are stable in suspension in aqueous media, have an outer layer composed of cyclodextrin [2]. The latter allows a post-functionalization of the nanoparticle by hydrophobic molecules through host-guest interactions. It appears that it is possible to modulate the site density of βCD at the surface of the shell of the hybrid glyconanoparticles while maintaining its inclusion properties. Moreover, the anchoring of glyconanoparticles to the surface of electrodes has been carried out by host-guest interactions with electrogenerated polymers. The efficient immobilization of the nanoparticles allows the anchoring of multilayers of biotinylated glucose oxidase. Finally, a new generation of bioelectrodes for oxygen reduction and electrical energy production will be described. This approach is based on the design of flat electrodes made of permeable and conductive materials defining a very thin microcavity with a large surface area containing, in a microvolume, enzymes in powder form. The concept has been demonstrated with bilirubin oxidase (BOD) for the electroenzymatic reduction of oxygen in water. Besides the influence of the amount of enzyme trapped in the microcavity on the performance of the bioelectrode, the functionalization of the electrodes by adsorption of redox mediators or compounds allowing an orientation of the BOD favorable to electron transfer was also explored. After 5 months of storage in an aqueous buffer, the bioelectrode exhibits 20% of its initial electro-enzymatic activity. Y. Nedellec, C. Gondran, K. Gorgy, S. MC Murtry, O. El Mazria, P. Agostini, S. Cosnier. Biosens. Bioelectron., 180, 113137-113141(2021). M. Carrière, P. H. M. Buzzetti, K. Gorgy, M. Mumtaz, C. Travelet, R. Borsali, S. Cosnier. Nanomaterials 11 (2021) 1162. doi.org/10.3390/nano11051162.
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Lonergan, Alex, i Colm O'Dwyer. "Methods to Tune the Optical Response of Porous Photonic Crystal Structures". ECS Meeting Abstracts MA2022-01, nr 47 (7.07.2022): 1984. http://dx.doi.org/10.1149/ma2022-01471984mtgabs.
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Photonic crystals are periodic dielectric structures which selectively tune the wavelengths of light propagating through the material1 2. The highly ordered, repeating structural lattice induces a photonic bandgap or stopband which inhibits or partially attenuates certain frequencies of light, similar to the electronic bandgap with forbidden energies present in semiconductor materials3. These forbidden frequencies are blocked in transmission and reflected from the material surface. The inherent sensitivity of this photonic response to repeating lattice size dimensions and the magnitude of the refractive index contrast between the constituent materials allows for tailored optical behaviour by adjusting the photonic crystal structural parameters or environment4 5. A range of interesting applications using both the photonic bandgap and material porosity have emerged, predicated on the ability to accurately forecast the wavelength position of the photonic response. Colorimetric sensors6 7, photocatalysts8 9 and solar cells10 are prime examples of these types of applications; the porosity of the photonic crystal facilitates greater material infiltration and reactions, while the photonic bandgap acts to enhance the optical component of the process. Critically, the use of these structures is tied to our ability to predict and interpret the signature optical response. Here, we examine several techniques which can be used modify the photonic bandgap/stopband for photonic crystal structures. For TiO2 and SnO2 inverse opal photonic crystals, we explore how solvent infiltration into the highly porous network red-shifts the observed photonic response. Using solvents with different refractive indices, we apply the shifted photonic stopband data to determine the fill fraction of solid material comprising the photonic crystal network. We also examine functionalization of artificial opal and inverse opal photonic crystals with metal films. We detail the emergence of a consistent photonic stopband blue-shift with increasing metal content and propose a reduction in the effective refractive index of the entire photonic crystal introduced by the specific properties of the metal film. Importantly, the effects investigated here are broadly applicable to a range of realistic operating conditions across many disciplines where an understanding of the photonic stopband is paramount to the application. References Yablonovitch, E., Inhibited Spontaneous Emission in Solid-State Physics and Electronics. Physical Review Letters 1987, 58 (20), 2059-2062. John, S., Strong localization of photons in certain disordered dielectric superlattices. Physical Review Letters 1987, 58 (23), 2486-2489. Joannopoulos, J. D.; Villeneuve, P. R.; Fan, S., Photonic crystals: putting a new twist on light. Nature 1997, 386 (6621), 143-149. Blanford, C. F.; Schroden, R. C.; Al-Daous, M.; Stein, A., Tuning Solvent-Dependent Color Changes of Three-Dimensionally Ordered Macroporous (3DOM) Materials Through Compositional and Geometric Modifications. Advanced Materials 2001, 13 (1), 26-29. Aguirre, C. I.; Reguera, E.; Stein, A., Tunable Colors in Opals and Inverse Opal Photonic Crystals. Advanced Functional Materials 2010, 20 (16), 2565-2578. Zhang, Y.; Qiu, J.; Hu, R.; Li, P.; Gao, L.; Heng, L.; Tang, B. Z.; Jiang, L., A visual and organic vapor sensitive photonic crystal sensor consisting of polymer-infiltrated SiO2 inverse opal. Physical Chemistry Chemical Physics 2015, 17 (15), 9651-9658. Li, H.; Chang, L.; Wang, J.; Yang, L.; Song, Y., A colorful oil-sensitive carbon inverse opal. Journal of Materials Chemistry 2008, 18 (42), 5098-5103. Chen, J. I. L.; von Freymann, G.; Choi, S. Y.; Kitaev, V.; Ozin, G. A., Amplified Photochemistry with Slow Photons. Advanced Materials 2006, 18 (14), 1915-1919. Collins, G.; Lonergan, A.; McNulty, D.; Glynn, C.; Buckley, D.; Hu, C.; O'Dwyer, C., Semiconducting Metal Oxide Photonic Crystal Plasmonic Photocatalysts. Advanced Materials Interfaces 2020, 7 (8), 1901805. Liu, L.; Karuturi, S. K.; Su, L. T.; Tok, A. I. Y., TiO2 inverse-opal electrode fabricated by atomic layer deposition for dye-sensitized solar cell applications. Energy & Environmental Science 2011, 4 (1), 209-215. Figure 1 SEM images and optical transmission spectra for (a) TiO2 and (b) SnO2 inverse opals. In each case the wavelength position of the photonic stopband is red-shifted significantly when a solvent infiltrates the porous photonic crystal network. SEM images and optical transmission spectra for (c) artificial polystyrene opals coated with a gold film and (d) TiO2 inverse opals coated with a copper film. Metal film incorporation into the photonic crystal network acts to consistent blue-shift the observed photonic stopband. Figure 1
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Nikolić, Sandra, Suzana Živanović, Miloš Papić, Marina Gazdić Janković, Miodrag Stojković i Biljana Ljujić. "Nanoplastics as a Potential Environmental Health Factor: From Molecular Interaction to Altered Cellular Function and Human Diseases". Serbian Journal of Experimental and Clinical Research, 29.01.2021. http://dx.doi.org/10.2478/sjecr-2020-0049.
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Abstract The problem of plastic pollution is becoming increasingly important and has attracted great interest in the last few years. Polystyrene is one of the most used plastic types in the food and beverage industry, medical and laboratory devices. Increased plastic production and increased food, water, and air pollution and contact with nanoplastics may cause long-lasting changes and predispose to adverse developmental and degenerative diseases through mechanisms that are not yet understood. The aim of this article is to provide an overview of current knowledge to plastics, especially polystyrene, and their impact on the human health. In particular, we discuss the major sources of plastic waste, polystyrene surface chemistry, as well as mechanisms by which plastics degrade in the environment. We also provide an insight into cellular uptake mechanism and the molecular interaction of polystyrene nanoparticles and human cells. This review offers scientists and clinicians useful information and could be used as a starting point for more in-depth analysis of nanoplastics as a potential environmental health factor.
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Manivannan, M., S. Sathiya Nathan, P. Sasikumar, L. Ramkumar, D. Navaneethan, P. Prabu, F. Mary Anjalin, N. Dharamarj, Mohammed S. Alqahtani i Mohamed Abbas. "Review on applications of Pullulan in bone tissue engineering: Blends and composites with natural and synthetic polymers". Polymers and Polymer Composites 31 (12.08.2023). http://dx.doi.org/10.1177/09673911231192810.
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Pullulan (PUL) has a diverse range of applicationsdue to its many therapeutic benefits, including biodegradability, biocompatibility, nontoxicity, antimicrobial activity, and adsorption. They are combined with chitosan, polyvinyl pyrrolidone (PVP), polycaprolactone (PCL), heparin, fluorescent polystyrene nanoparticles (PS-NPs), and carboxyl Pullulan to develop properties such as thermal stability, mechanical properties, pH resistance, chemical stability, toughness. The effects of Pullulan content on the properties of the solution, as well as the morphology of the resultant nanofibers, were investigated >80%. The concept of a scaffold can be a useful notion to improve the mechanical behavior of hydrogel-based scaffolds. Compositional analysis by Differential scanning calorimetry (DSC) revealed that Pullulan might enhance the mechanical properties of the nanofibers. This review focuses on the combination and analysis of Pullulan blends and composites of natural and synthetic polymers, as well as their capability in biomedical fields and bone tissue engineering, for example in drug delivery, insulin delivery, food industry, medicinal and biomedical applications, antimicrobial wound dressings, cancer cell targeting, anticancer vaccine improvement, new biopolymer development, food product development and sensing. The electro spinning procedure and the materials employed in it will be covered in this review. The use of Pullulan electrospun nanofibers structures in tissue engineering will also be covered in this paper. The benefits, restrictions, and future opinions were studied. This is because of Pullulan-based polymers have a variety of properties.
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Surette, Mark C., Denise M. Mitrano i Kim R. Rogers. "Extraction and concentration of nanoplastic particles from aqueous suspensions using functionalized magnetic nanoparticles and a magnetic flow cell". Microplastics and Nanoplastics 3, nr 1 (27.01.2023). http://dx.doi.org/10.1186/s43591-022-00051-1.
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AbstractAlthough a considerable knowledge base exists for environmental contamination from nanoscale and colloidal particles, significant knowledge gaps exist regarding the sources, transport, distribution, and effects of microplastic pollution (plastic particles < 5 mm) in the environment. Even less is known regarding nanoplastic pollution (generally considered to be plastic particles < 1 μm). Due to their small size, nanoplastics pose unique challenges and potential risks. We herein report a technique focused on the concentration and measurement of nanoplastics in aqueous systems. Hydrophobically functionalized magnetic nanoparticles (HDTMS-FeNPs) were used as part of a method to separate and concentrate nanoplastics from environmentally relevant matrices, here using metal-doped polystyrene nanoplastics (PAN-Pd@NPs) to enable low-level detection and validation of the separation technique. Using a magnetic separation flow cell, PAN-Pd@NPs were removed from suspensions and captured on regenerated cellulose membranes. Depending on the complexity of solution chemistry, variable extraction rates were possible. PAN-Pd@NPs were recovered from ultrapure water, synthetic freshwater, synthetic freshwater with a model natural organic matter isolate (NOM; Suwannee River Humic Acid), and from synthetic marine water, with recoveries for PAN-Pd@NPs of 84.9%, 78.9%, 70.4%, and 56.1%, respectively. During the initial method testing, it was found that the addition of NaCl was needed in the ultrapure water, synthetic freshwater and synthetic fresh water with NOM to induce particle aggregation and attachment. These results indicate that magnetic nanoparticles in combination with a flow-through system is a promising technique to extract nanoplastics from aqueous suspensions with various compositions.
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Andone Rotaru, B. A., M. Girlovanu, A. Vulpoi, I. Botiz i S. Boca. "P-018 Structural and biocompatibility analysis of gold nanoparticle integrated polymeric scaffolds for infertility diagnosis". Human Reproduction 38, Supplement_1 (1.06.2023). http://dx.doi.org/10.1093/humrep/dead093.385.
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Abstract Study question Can infertility diagnosis and sperm selection be improved by using bio- nanotechnologies? Summary answer Gold nanoparticle integrated biopolymeric scaffolds show good biocompatibility when interacting with human sperm cells, being suitable to be used as cell sorting and biosensing platforms. What is known already Microfluidic platforms are used in sperm selection for increasing the in-vitro fertilization success but they are limited by the exclusive analysis of sperm cell motility. The integration of microfluidic platforms with nanomaterials such as nanopatterned substrates can greatly enhance the selectivity and the sensitivity of the detection. The accuracy can be further improved by employing the intrinsic properties of gold nanoparticles (optical properties, high biocompatibility, surface chemistry favoring the conjugation of specific biomolecules), which makes them suitable for the successful development of precise and reliable detection assays, so far used to a limited extent in infertility research and clinical approaches. Study design, size, duration Concentration, motility and morphology of spermatozoa were analyzed in semen samples collected for spermogram. The normozoospermic and teratozoospermic samples were selected and prepared by density gradient centrifugation. The sediment obtained contained 100% motile spermatozoa, which were incubated on the thin films for 24h. After 24h, the probe from each incubation dish was collected and the survival rate was analyzed using the Makler chamber. Participants/materials, setting, methods Thin films of atactic polystyrene, chitosan and mixtures of each of the two polymers with gold nanoparticles were used to produce scaffolds of microchannels. The substrates were morphologically characterized by optical microscopy, scanning transmission electron microscopy and atomic force microscopy. Normozoospermic and teratozoospermic sperm samples were collected and incubated on the scaffolds. After 24h incubation, the viability was assessed by counting the motile spermatozoa under microscopic observation. Statistical analysis was performed using two-way ANOVA test. Main results and the role of chance Analysis of the sperm cell viability incubated on the polymeric scaffolds revealed good biocompatibility with higher survival rate in the case of chitosan-gold nanoparticle integrated samples. In multiple comparisons of normozoospermic samples, the survival rates of the sample incubated on the chitosan thin films to the control sample were 18% to 80% (-62%) (p = 0.0143), 16.66% to 45% (-28.34%) (p = 0.0143), 0% to 15.38% (-15.38%) (p = 0.0239), 4.76% to 55.35% (-50.59%) (p = 0.0239). In multiple comparisons of teratozoospermic samples, the survival rates of the sample incubated on the chitosan thin films to the control sample were 14.67% to 41% (-26.33%) (p = 0.0143), 0% to 44.82% (-33.82%) (p = 0.0239). For polystyrene, the viability was 0% which excludes its further use in infertility-related assays due to its high cytotoxicity. Overall, the colloidal gold nanoparticles integrated into the polymeric matrix improved the biocompatibility of the films. For example, citrate gold nanoparticles of spherical shape and sizes of about 20 nm increased the survival rate of normozoospermic samples, while PEGylation of nanoparticles showed further improvement of the biocompatibility. The influence of the particle type, composition and coating material onto the spermatozoa viability is currently under investigation for optimizing the effectiveness of the polymeric scaffolds. Limitations, reasons for caution NA Wider implications of the findings Due to the unique properties of gold nanoparticles, the nanoparticle-polymer scaffold systems have the potential to become the foundation of a precise biosensor that can enhance the accuracy of the current approaches in infertility assessment. Trial registration number Not applicable
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"Raymond John Heaphy Beverton, C. B. E., 29 August 1922 - 23 July 1995". Biographical Memoirs of Fellows of the Royal Society 42 (listopad 1996): 24–38. http://dx.doi.org/10.1098/rsbm.1996.0003.
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Ray Beverton was born on the 29 August 1922, the only child of Edgar John Beverton and Dorothy Sybil Mary Beverton. His father was a commercial artist and his mother, too, came from an artistic family; indeed an ancestor was Sir Thomas Heaphy, a portrait painter and official war artist at Waterloo. Another forebear won the V.C. As a young child Ray acquired enthusiasms for music, fishing and football, activities which were dear to him throughout his life; in later years he became very fond of sailing. He was a regular supporter of West Ham United - the Hammers - until he moved to Swindon. When eight years old he entered his first angling competition and in later life he rarely took a holiday or trip abroad without his fishing rods. He went to school at the Forest School, Snaresbrook and then to Downing College, Cambridge (1940-42), where he read physics, chemistry and mathematics in Part I of the Natural Sciences Tripos. Between 1942 and 1945 he worked at the Operational Research Group developing polystyrene and latex for the insulation of coaxial cables for radar. During this time he retained his links with Cambridge and when in 1945, Michael Graham, the newly appointed Director of Fisheries Research, asked his former tutor, Sir James Gray, F.R.S, for an able young graduate to extend his studies on the exploitation of the North Sea cod (Graham 1935, 1938 a ), Ray was introduced to him. Ray wrote ‘I first met Michael Graham in the late summer of 1945 in a small space carved out of the racks of dusty files in St Stephen’s House. He gave me a copy of his book, The Fish Gate (Graham 1943). Within a month he took me with him on a Grimsby trawler to the Barents Sea fishing grounds’ (1)*. Ray suffered badly from sea sickness and wrote three letters of resignation, which fortunately he did not send. He spent a year in Lowestoft from 1945-46. During this time he wrote the first chapter of Graham’s Buckland lecture (2), one of a series which are given from time to time by scientists to audiences of fishermen; both Ray and Michael used the English language well, if differently. The amalgam is a delightful study of Frank Buckland, one of the ancestors of fisheries research. In 1946, Ray returned to Cambridge to read zoology in Part II of the Tripos and he gained the top first class degree in his year and the Smart Prize for zoology; he also won a Blue for soccer. He returned to Lowestoft in 1947 and married Kathleen Edith Marner the same year. They had three daughters, Susan, Valerie and Julia. *Numbers in this form refer to the bibliography at the end of the text.