Search

Abstract: Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), an antioxidant widely applied in the plastic industry, was used to assist thermal reduction of graphene oxide (GO) on a cotton fabric in air. L-ascorbic acid was also applied for comparison. GO was deposited on the fabric by the padding method. Reduction of GO deposited on fiber surfaces at 180 and 220 °C in air imparted electrical conductivity. For all the materials the conductivity worsened after the reduction during cooling and during the first hours of storage at room conditions. However, the most stable effect of GO reduction was achieved using pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), which assisted the reduction of GO at both 180 and 220 °C, and allowed to obtain the cotton fabric with a stable surface resistivity of 6.6 and 3.7 MΩ/sq, respectively. Moreover, superhydrophobicity of the conductive fabric was achieved by modification with methyltrichlorosilane in an anhydrous environment.Graphical abstract: [ABSTRACT FROM AUTHOR]

Abstract: Highly branched methoxy substituted phenylsilsesquioxane-silicate copolymers were obtained by dehydrocarbon polycondensation of phenylsilane (PhSiH3) with tetramethoxysilane (TMOS) in toluene solution catalyzed by tris(pentafluorophenyl)borane [B(C6F5)3]. This model reaction represents a new non-hydrolytic route to TQ silicone resins, which do not contain reactive and hydrophilic silanol groups and therefore, should be more stable and have better miscibility with some organic polymers. The soluble siloxane copolymers, which do not contain volatile oligomers, were obtained using the PhSiH3:TMOS molar ratios below 0.9. The dehydrocarbon condensation is accompanied by metathetic exchange of hydrosilyl and methoxysilyl functions, which is responsible for the formation of links between units originating from the same comonomer. Competition between the dehydrocarbon condensation and metathesis is consistent with a mechanism involving the transient formation of a tertiary oxonium ion intermediate. 29Si NMR analysis of the copolymer product proves that extensive cyclization occurs during the polycondensation, most likely leading to a significant proportion of ladder and cage like structures. [Copyright &y& Elsevier]

The paper describes preparation and electrical properties of hybrid materials obtained from cotton or polyester woven fabrics that were modified with three-dimensional multiwall carbon nanotube networks deposited on fibers surface and additionally functionalized superhydrophobically. The effects of a degree of multiwall carbon nanotubes deposition on electric resistivity as well as on its temperature dependence, mechanical behavior and of additional hydrophobization, are presented. It is demonstrated that, similarly to cotton, polyester woven fabric can be successfully used to obtain material with superhydrophobic properties by treatment in a trichloromethylsilane solution, in an anhydrous environment. The obtained results demonstrated that - in contrast to cotton fabrics - surface area and water content in polyester fabrics have little influence on the hydrophobic properties of the obtained samples of modified polyester fabrics. [ABSTRACT FROM AUTHOR]

The paper presents the results of modifying and testing modern hybrid polyester–cotton woven fabrics with deposited multi-wall carbon nanotubes and imparted hydrophobicity. The effect of the carbon nanotubes deposited on these fabrics on their conductive properties and hydrophobicity has been assessed. The electro-conductive and hydrophobic composite fabrics obtained in this way, being light, elastic and resistant to mechanical effects, make it possible to be widely used in various industrial fields. [ABSTRACT FROM AUTHOR]

Background and Objectives: More than 430,000 new cases of renal cell carcinoma (RCC) were reported in 2020. Clear cell RCC, which occurs in 80% of cases, is often associated with mutations in the VHL gene, leading to dysregulation of hypoxia-induced transcription factors pathways and carcinogenesis. The purpose of this study is to examine the adverse events (AEs) of cabozantinib treatment and the relationship between individual patient factors and the frequency of their occurrence in detail. Materials and Methods: Seventy-one patients with metastatic RCC were treated with second or further lines of cabozantinib at the Department of Genitourinary Oncology, Maria Sklodowska-Curie National Research Institute of Oncology. Comprehensive data, including demographics, clinicopathological factors, and AEs, were collected from January 2017 to June 2021. This study evaluated the impact of various patient-related factors on the rate of adverse events and treatment tolerance using a Cox proportional hazards model. Results: Cabozantinib-induced AEs were significantly associated with body mass index (BMI), body surface area (BSA), IMDC prognostic score, and treatment line. Notably, patients receiving cabozantinib post-tyrosine kinase inhibitors reported fewer AEs. Dose reduction was unrelated to adverse event frequency, but patients requiring dose reduction were characterized with lower body mass and BSA but not BMI. Conclusions: The factors described make it possible to predict the incidence of AEs, which allows for faster detection and easier management, especially in the high-risk group. AEs should be reported in detail in real-world studies, as their occurrence has a significant impact on prognosis.

Introduction: Urothelial carcinoma is the most common type of urinary tract malignancy. Current treatment options, including platinum-based chemotherapy or immunotherapy, present significant challenges, ranging from limited efficacy to severe toxicities. Recent developments in antibody-drug conjugates (ADC), such as enfortumab vedotin (EV), promise to significantly improve overall survival. The study aims to evaluate the efficacy and tolerability of EV. In addition, we highlight the observed benefits of next-line treatment after progression., Material and Methods: This retrospective study involved 16 patients with advanced urothelial cancer treated with EV at the Department of Genitourinary Oncology, Maria Skłodowska- Curie National Research Institute of Oncology between November 2022 and November 2023. The study evaluated patients' medical history, response to EV treatment, and side effects. Notably, the study included patients who had already exhausted standard treatment options and who were treated with EV through a rescue access procedure., Results: Partial response was observed in 4 out of 9 (44%) patients with available imaging. Common terminology criteria for adverse events (AE) grade 3 and 4 were observed in 3 out of 16 patients, which subsequently required dose reduction., Conclusions: Enfortumab vedotin demonstrates effectiveness in real-world settings in treating advanced urothelial cancer. Proper management of AE in experienced centres may further prolong survival. Personalized treatment and the development of new ADC represent the future for improved patient outcomes., Competing Interests: BSK Honoraria: Angelini, Astellas, Astra Zeneca, Bayer, Bristol Myers Squibb, IPSEN, Janssen, Merck MSD, Novartis, Pfizer. All unrelated to the present paper. JK Honoraria: Angelini, Astellas, Astra Zeneca, Bayer, Bristol Myers Squibb, IPSEN, Janssen, Merck MSD, Novartis, Pfizer, Research Funding: Novartis.The authors declare no conflict of interest., (Copyright © 2023 Termedia.)

The branching and cross-linking of siloxane polymers are important processes in silicone technology. A new type of such a process has been developed, which is a self-restructuring of linear polyhydromethylsiloxane (PHMS). This process involves the reorganization of the PHMS to form a highly branched siloxane polymer or finally a cross-linked siloxane network. It occurs through the transfer of a hydride ion between silicon atoms catalyzed by tris(pentafluoromethyl)borane. Its advantage over existing branching and cross-linking reactions is that it runs at room temperature without a low-molecular-weight cross-linker in the absence of water, silanol groups, or other protic compounds and it does not use metal catalysts. The study of this process was carried out in toluene solution. Its course was followed by 1 H NMR, 29 Si NMR and FTIR, SEC, and gas chromatography. A general mechanism of this new self-restructuring process supported by quantum calculations is proposed. It has been shown that a linear PHMS self-restructured to a highly branched polymer can serve as a pure methylsiloxane film precursor.

Graphene oxide (GO) was deposited on a cotton fabric and then thermally reduced to reduced graphene oxide (rGO) with the assistance of L-ascorbic acid. The GO reduction imparted electrical conductivity to the fabric and allowed for electrochemical deposition of Ag° particles using cyclic voltammetry. Only the Ag°/rGO composite coating imparted antibacterial properties to the fabric against Escherichia coli and Staphylococcus aureus . Ag°/rGO-modified fibers were free of bacterial film, and bacterial growth inhibition zones around the material specimens were found. Moreover, Ag°/rGO-modified fabric became superhydrophobic with WCA of 161°.

A simple and inexpensive method for the preparation of porous SiC microspheres is presented. Polysiloxane microspheres derived from polyhydromethylsiloxane (PHMS) cross-linked with divinylbenzene (DVB) were ceramized under conditions leading to the removal of oxygen from the material. The content of free carbon (C f ) in highly crystalline silicon carbide (SiC) particles can be controlled by using various proportions of DVB in the synthesis of the pre-ceramic material. The chemical structure of the ceramic microspheres was studied by elemental analysis for carbon and oxygen, 29 Si MAS NMR, 13 C MAS NMR, SEM/EDS, XRD and Raman spectroscopies, and their morphology by SEM, nitrogen adsorption and mercury intrusion porosimetries. The gaseous products of the thermal reduction processes formed during ceramization created a porous structure of the microspheres. In the SiC/C f microspheres, meso/micro pores were formed, while in carbon-free SiC, microspheres macroporosity dominated.

Reduction of Ge(OBu)4 with PhMe2SiH catalyzed by B(C6F5)3 at ambient temperature leads to GeH4. We discovered that a higher temperature (above 100 °C) completely changes the reaction course by producing germanium nanoparticles (Ge NPs) in high yield. This process provides a simple one-pot method for Ge NPs synthesis from readily available substrates under mild conditions.

Six liquid branched poly(methylhydrosiloxanes) of new random structures (PMHS-Q), containing quadruple branching units SiO 4/2 (Q), both MeHSiO (D H ) and Me₂SiO (D) chain building units (or only mers MeHSiO), and terminal groups Me₃SiO 0.5 (M) were prepared by a hydrolytic polycondensation method of appropriate organic chlorosilanes and tetraethyl ortosilicate (TEOS), in diethyl ether medium at temperature below 0 °C. Volatile low molecular weight siloxanes were removed by a vacuum distillation at 150⁻155 °C. Yields of PMHS-Q reached from 55⁻69 wt%. Their dynamic viscosities were measured in the Brookfield HBDV+IIcP cone-plate viscometer and ranged from 10.7⁻13.1 cP. Molecular weights (MW) of PMHS-Q (M n = 2440⁻6310 g/mol, M w = 5750⁻10,350 g/mol) and polydispersities of MW (M w /M n = 2.0⁻2.8) were determined by a size exclusion chromatography (SEC). All polymers were characterized by FTIR, ¹H- and 29 Si-NMR, and an elemental analysis. A microstructure of siloxane chains was proposed on a basis of 29 Si-NMR results and compared with literature data.

Antibacterial polysiloxane polymers with pending tert-butylamine groups are a novel class of compounds that are compatible with silicone elastomers, but their mechanism of action is not well understood. The research into their action mechanism was conducted on a polysiloxane copolymer grafted with tert-butylaminoethyl methacrylate and covalently attached fluorescein. Fluorometric measurements results suggest that the polymer forms a stable link with bacteria. The results of β-galactosidase enzyme assay with the use of ortho-nitrophenyl-β-galactoside as a substrate show that the polymer has a damaging effect on bacterial membranes. The scanning and transmission electron micrographs of Escherichia coli cells incubated with the polymer prove further that the polymer's site of action is bacterial cell membranes. In order to investigate the polymer interaction with bacterial membranes the fluorescein labelled polymer was incubated with bacterial cells and membranes isolation and identification method was next applied. The E. coli membrane fractions were identified by light scattering, protein content, oxidase NADH activity and N-phenylnaphtylamine fluorescence measurements, as well as electron microscopy. Oxidase NADH and N-phenylnaphtylamine were the inner membrane markers. The bacterial membranes were then tested for the presence of the polymer. The experiments gave evidence that the copolymer binds to the inner bacterial membrane. Further studies, where the copolymer was incubated with isolated mixed (inner and outer) membrane fractions, proved that the copolymer exerts more destructive effect on E. coli outer membrane. The damaging effect on the membranes is concentration dependent.

Disease-causing bacteria of the genus Aeromonas are able to adhere to pipe materials, colonizing the surfaces and forming biofilms in water distribution systems. The aim of our research was to study how the modification of materials used commonly in the water industry can reduce bacterial cell attachment. Polyvinyl chloride and silicone elastomer surfaces were activated and modified with reactive organo-silanes by coupling or co-crosslinking silanes with the native material. Both the native and modified surfaces were tested using the bacterial strain Aeromonas hydrophila, which was isolated from the Polish water distribution system. The surface tension of both the native and modified surfaces was measured. To determine cell viability and bacterial adhesion two methods were used, namely plate count and luminometry. Results were expressed in colony-forming units (c.f.u.) and in relative light units (RLU) per cm(2). Almost all the chemically modified surfaces exhibited higher anti-adhesive and anti-microbial properties in comparison to the native surfaces. Among the modifying agents examined, poly[dimethylsiloxane-co-(N,N-dimethyl-N-n-octylammoniopropyl chloride) methylsiloxane)] terminated with hydroxydimethylsilyl groups (20 %) in silicone elastomer gave the most desirable results. The surface tension of this modifier, was comparable to the non-polar native surface. However, almost half of this value was due to the result of polar forces. In this case, in an adhesion analysis, only 1 RLU cm(-2) and less than 1 c.f.u. cm(-2) were noted. For the native gumosil, the results were 9,375 RLU cm(-2) and 2.5 × 10(8) c.f.u. cm(-2), respectively. The antibacterial activity of active organo-silanes was associated only with the carrier surface because no antibacterial compounds were detected in liquid culture media, in concentrations that were able to inhibit cell growth.

The coemulsification method suitable for the formulation of microcapsules of n -eicosane coated with a polysiloxane is developed. This method allows to synthesize core-shell microcapsules of paraffin which have the shape of spheres or distorted spheres and are designed for the use as phase change materials. The microcapsules are formed in aqueous phase by the precipitation of n -eicosane together with modified polyhydromethylsiloxane from a common solvent which is miscible with aqueous media. The polysiloxane is modified by the attachment of silylvinyl and alkoxy functions before coemulsification with the paraffin. It also contains the Pt(0) Karstedt catalyst. The microcapsules formed by coemulsification are stabilized by the in situ cross-linking of the polysiloxane shell. The shell is additionally modified by the in situ generation of silanol groups which provide colloidal stabilization of microspheres in aqueous phase. Microcapsules were studied by DSC, SEM, optical polarized microscope, and by thermooptical analysis (TOA).