Advances in nanostructured metal-encapsulated porous organic-polymer composites for catalysed organic chemical synthesis

Abstract: Porous organic polymers (POPs) are of growing research interest owing to their high surface areas, stabilities, controllable chemical configurations, and tunable pore volumes. The molecular nanoarchitecture of POP provides metal or metal oxide binding sites, which is promising for the development of advanced heterogeneous catalysts. This article highlights the development of numerous kinds of POPs and key achievements to date, including their functionalization and incorporation of nanoparticles into their framework structures, characterization methods that are predominantly in use for POP-based materials, and their applications as catalysts in several reactions. Scientists today are capable of preparing POP-based materials that show good selectivity, activity, durability, and recoverability, which can help overcome many of the current environmental and industrial problems. These POP-based materials exhibit enhanced catalytic activities for diverse reactions, including coupling, hydrogenation, and acid catalysis

Nafion Titania Nanotubes Nanocomposite Electrolytes for High-Temperature Direct Methanol Fuel Cells

Nafion-based nanocomposite membranes containing various amounts of titania nanotubes (TNTs) as an inorganic filler have been prepared using melt-mixing method and have been investigated for proton exchange membrane applications. The one-dimensional TNTs have been prepared from potassium hydroxide using hydrothermal route and conventional heating. Nafion R1100 in a protonated form was used, and TNT contents were in a range of 0.5–2.0 wt%. The acid-treated composite membranes, at lowest inorganic additive content, exhibited improved properties in terms of thermal stability and methanol (MeOH) permeability. The best performing nanocomposite was the membrane containing only 0.5 wt% TNTs showing ionic conductivity value of 7.2×10-2 S·cm-1 at 26°C and 100% of relative humidity

Apoptotic efficacy of multifaceted biosynthesized silver nanoparticles on human adenocarcinoma cells

Abstract: Metallic nanoparticles (NPs) especially silver (Ag) NPs have shown immense potential in medical applications due to their distinctive physio-chemical and biological properties. This article reports the conjugation of Ag NPs with Rubus fairholmianus extract. The modification of Ag NPs was confirmed using various physico-chemical characterization techniques. The cytotoxic effect of Rubus-conjugated Ag NPs (RAgNPs) was studied by LDH assay and proliferation by ATP assay. The apoptotic inducing ability of the NPs were investigated by Annexin V/PI staining, caspase 3/7 analysis, cytochrome c release, intracellular ROS analysis, Hoechst staining and mitochondrial membrane potential analysis using flow cytometry. The expression of apoptotic proteins caspase 3, Bax and P53 were analyzed using ELISA and caspase 3, Bax using western blotting. Cells treated with 10 µg/mL RAgNPs showed an increased number of cell death by microscopic analysis compared to untreated control cells. The RAgNPs induced a statistically significant dose-dependent decrease in proliferation (p < 0.001 for 5 and 10 µg/mL) and increased cytotoxicity in MCF-7 cells. A 1.83 fold increase in cytotoxicity was observed in cells treated with 10 µg/mL (p < 0.05) compared to the untreated cells. Nuclear damage and intracellular ROS production were observed upon treatment with all tested concentrations of RAgNPs and the highest concentrations (5 and 10 µg/mL) showed significant (p < 0.05, p < 0.01) expression of caspase 3, Bax and P53 proteins. The data strongly suggest that RAgNPs induces cell death in MCF-7 cells through the mitochondrial-mediated intrinsic apoptosis pathway. The present investigation supports the potential of RAgNPs in anticancer drug development

Properties of thermoplastic maize starch-zein composite films prepared by extrusion process under alkaline conditions

DATA AVAILABILITY : Data will be made available on request.This work investigates the effect of the addition of NaOH on the compatibility and material properties of thermoplastic starch-zein composite films produced by a twin-screw extruder. Thermoplastic starch-zein composite films were produced by melt extrusion of glycerol-plasticized starch and zein (3:1 ratio) treated with different concentrations of sodium hydroxide (NaOH) (0 M, 0.05 M, 0.1 M, and 0.2 M NaOH). Scanning Electron Microscope and Confocal laser Scanning Microscope revealed that the composite without NaOH formed a phase-separated morphology with large zein aggregates within the starch matrix. However, the increase in NaOH concentration reduced the size of zein aggregates within the starch-zein composite films, with 0.2 M NaOH having the smallest size of zein aggregates. Dynamic mechanical analysis showed a decrease in glass transition temperature (Tg) and storage modulus (E'), suggesting more molecular chain mobility and efficient plasticization of starch and zein. This efficient plasticization was also confirmed by Fourier-Transform Infrared spectroscopy (FTIR). As a result, there was an optimal increase of 28% in elongation at break in the starch-zein composite film with 0.2 M NaOH. In conclusion, compatible thermoplastic starch-zein composite films with improved elongation at break can be produced with a twin-screw extruder by adding 0.2 M NaOH.DSI/NRF Centre of Excellence in Food Security.http://www.elsevier.com/locate/ijbiomachj2023Consumer ScienceFood Scienc

Structural and Photoprotective Characteristics of Zn-Ti, Zn-Al, and Mg-Al Layered Double Hydroxides—A Comparative Study

Organic UV filters have been known to generate harmful by-products and undergo photoreactive degradation, which ultimately poses a great threat to consumers using sunscreen products. Inorganic UV filters such as TiO2 and ZnO, although considered safer options, are not without threat considering their photocatalytic nature and ability to generate reactive oxygen species. A study was conducted to identify the influence of different metal ions on the photochemical properties of layered double hydroxides (LDH), Zinc-Titanium LDH (Zn-Ti LDH), Zinc-Aluminium LDH (Zn-Al LDH), and Magnesium- Aluminium LDH (Mg-Al LDH) and their prospects in photoprotection. The photocatalytic properties of the LDH were analyzed and compared to TiO2 and ZnO. The intermediate band gaps of Zn-Ti (3.72 eV) and Zn-Al LDH (3.3 eV) proved favorable and safer for the use of these LDH in cosmetic formulations as they offer lower photo-reactivity when compared to cosmetic grade ZnO and TiO2. The in vitro SPF values obtained for formulations containing 2 wt% Zn-Ti and 2 wt% Zn-Al LDH showed promise, with both samples claiming “broad spectrum” protection and valid claims of UVA protection

V-amylose structural characteristics, methods of preparation,significance and potential applications

The amylose component of starch can form complexes known as V-amylose with amphiphilic or hydrophobic ligands. The V-amylose complexes are single, left-handed helices that are arranged as crystalline and amorphous lamellae, which may form distinct nano- or micron-scale structures. V-amylose has potential as a biomaterial for nanoencapsulation of sensitive bioactive and flavor ingredients, modification of rheological behavior of starch-containing products, reduction of starch retrogradation, and postprandial hyperglycaemia in diabetics. Various aspects of V-amylose structure, methods of preparation, factors that affect its formation, and the significance and potential applications of the V-amylose complexes are reviewed.University of Pretoria Commonwealth Scholarship Programme, DST/CSIR Nanotechnology Innovation Centre, and National Research Fund (NRF)http://www.tandfonline.com/doi/abs/hb201

Field Emission Characteristics of SnO

The SnO2/CNT composites were prepared by microwave-assisted wet impregnation at 60°C. The process was optimized by varying the microwave power and reaction time. Raman analysis showed the typical features of the rutile phase of as-synthesized SnO2 nanoparticles on CNTs, which was consistent with the results from X-ray diffraction. Enhanced field emission performance was observed for SnO2/CNTs composite prepared by a microwave method when compared to pure CNTs and SnO2/CNTs composite prepared by conventional wet impregnation. The dependence of emission current density on the electric field followed a Fowler-Nordheim relationship

Development and Characterization of Poly(butylene succinate-co-adipate)/Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with Cowpea Lignocellulosic Fibers as a Filler via Injection Molding and Extrusion Film-Casting

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