Organic–inorganic nanocomposites prepared from fluoro-aramid and silica

Fluoro-aramid-based sol/gel-derived nanocomposites were synthesized by condensing a mixture of 4,4′-(hexafluoro-isopropylidene)dianiline and 1,3-phenylenediamine with terephthaloylchloride (TPC) in dimethylacetamide. TPC was added in slight excess to produce amide chains with carbonyl chloride end groups and then replaced with alkoxy groups using aminophenyltrimethoxysilane to develop bonding with the silica network. Mechanical, dynamic mechanical thermal, water absorption and morphological measurements were carried out on the thin hybrid films. Increase in the tensile strength and modulus was observed as compared to pristine polyamide. The thermal decomposition temperature was found in the range of 400–500 °C. The water absorption was found to be reduced with higher silica content. The glass transition temperature and the storage moduli increased with increasing silica concentration. The maximum increase in the T _g value (345 °C) was observed with 20 wt% silica. Scanning electron microscopy revealed the uniform distribution of silica in the matrix with an average particle size ranging from 8 to 50 nm.     

Stable gaseous aziridinium ions

Gaseous protonated aziridine ions are produced at the threshold from β-phenoxyethylamine molecular ions. The evidence for this is collisional activation spectra, using various precursors (including labelled analogues) under electron impact and field ionization conditions. Partial conversion to the acyclic \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} {\rm CH = }\mathop {\rm N}\limits^ + {\rm H}_{\rm 2} $\end{document} isomer occurs at higher electron energies and is rationalized by means of a potential energy surface constructed from energetic data.     

In-situ green synthesis of highly active GSH-capped Pt–Au–Ag-hybrid nanoclusters

Recently much attention has been paid to the application of metal hybrid nanoparticles in industrial catalytic fields because of their super-efficient catalytic activity and attractive properties. We explored a novel strategy to prepare GSH-capped Pt–Au–Ag-hybrid nanoclusters through the synergistic effect between ascorbic acid(VC) and glutathione(GSH) with chloroplatinic acid, chloroauric acid, and silver nitrate as precursors. The potential utilization of as-prepared GSH-capped Pt–Au–Aghybrid nanoclusters for catalytic applications has been evaluated through the reduction of 4-nitrophenol(4-NP) with NaBH4; we obtained the kinetic data by monitoring with UV-Vis spectroscopy. Our results illustrate that GSH-capped Pt–Au– Ag-hybrid nanoclusters could facilitate the process of reduction of 4-NP in a way that is unprecedented. This approach may offer a novel, non-cytotoxicity, efficient catalyst for industry.     

Experimental comparison of performance and emission characteristics of 4-stroke CI engine operated with Roselle and Jatropha biodiesel blends

The environmental degradation, combined with the continuous depletion of the world's fossil fuel reserves, has forced the search for alternative fuels. This study was performed to investigate the performance of novel biodiesels in the CI engine. The experiments were performed at three different compressions ratios (16:1, 17:1, 18:1) and four loading conditions (25%, 50%, 75%, 100%). Different types of fuels such as jatropha biodiesel (JB), roselle biodiesel (RB), and ternary biodiesel (TB) were prepared and analyzed. The thermal performance of different fuels was analyzed in terms of brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), and exhaust gas temperature (EGT). The emission characteristics such as CO₂ emission, NO_x emission, and smoke emission were analyzed for all types of fuels. The results of these fuels in the engine were compared with mineral diesel (MD). The BTE was increased with increasing compression ratios and loads for all types of fuels. The BSFC was increased with increasing compression ratios but decreased with increasing loads. The increase in emission of NO_x was observed at higher compression ratios and loads. However, the CO₂ emission was decreased at higher loads and lower compression ratio. The performance curves achieved with a 20% jatropha biodiesel blend showed results that were approximate to those obtained with pure MD. The comparative analysis between different fuels showed that JB exhibit higher thermal performance as compared to other biodiesels. Therefore, JB can be a better alternative to conventional fuel.     

Biomedical Applications of Scutellaria edelbergii Rech. f.: In Vitro and In Vivo Approach

In the current study, in vitro antimicrobial and antioxidant activities and in vivo anti-inflammatory and analgesic activities of Scutellaria edelbergii Rech. f. (crude extract and subfractions, i.e., n-hexane, ethyl acetate (EtOAc), chloroform, n-butanol (n-BuOH) and aqueous) were explored. Initially, extraction and fractionation of the selected medicinal plant were carried out, followed by phytochemical qualitative tests, which were mostly positive for all the extracts. EtOAc fraction possessed a significant amount of phenolic (79.2 ± 0.30 mg GAE/g) and flavonoid (84.0 ± 0.39 mg QE/g) content. The EtOAc fraction of S. edelbergii exhibited appreciable antibacterial activity against Gram-negative (Escherichia coli and Klebsiella pneumoniae) strains and significant zones of inhibition were observed against Gram-positive bacterial strains (Bacillus subtilis and Staphylococcus aureus). However, it was found inactive against Candida Albicans and Fusarium oxysporum fungal strains. The chloroform fraction was the most effective with an IC₅₀ value of 172 and 74 µg/mL against DPPH (1,1-Diphenyl-2-picryl-hydrazyl) and ABTS assays, in comparison with standard ascorbic acid 59 and 63 µg/mL, respectively. Moreover, the EtOAc fraction displayed significant in vivo anti-inflammatory activity (54%) using carrageenan-induced assay and significant (55%) in vivo analgesic activity using acetic acid-induced writing assay. In addition, nine known compounds, ursolic acid (UA), ovaul (OV), oleanolic acid (OA), β-sitosterol (BS), micromeric acid (MA), taraxasterol acetate (TA), 5,3′,4′-trihydroxy-7-methoxy flavone (FL-1), 5,7,4′-trihydroxy-6,3′-dimiethoxyflavone (FL-2) and 7-methoxy catechin (FL-3), were isolated from methanolic extract of S. edelbergii. These constituents have never been obtained from this source. The structures of all the isolated constituents were elucidated by spectroscopic means. In conclusion, the EtOAc fraction and all other fractions of S. edelbergii, in general, displayed a significant role as antibacterial, free radical scavenger, anti-inflammatory and analgesic agents which may be due to the presence of these constituents and other flavonoids.     

Selenium Alleviates the Adverse Effect of Drought in Oilseed Crops Camelina (Camelina sativa L.) and Canola (Brassica napus L.)

Drought poses a serious threat to oilseed crops by lowering yield and crop failures under prolonged spells. A multi-year field investigation was conducted to enhance the drought tolerance in four genotypes of Camelina and canola by selenium (Se) application. The principal aim of the research was to optimize the crop yield by eliciting the physio-biochemical attributes by alleviating the adverse effects of drought stress. Both crops were cultivated under control (normal irrigation) and drought stress (skipping irrigation at stages i.e., vegetative and reproductive) conditions. Four different treatments of Se viz., seed priming with Se (75 μM), foliar application of Se (7.06 μM), foliar application of Se + Seed priming with Se (7.06 μM and 75 μM, respectively) and control (without Se), were implemented at the vegetative and reproductive stages of both crops. Sodium selenite (Na₂SeO₃), an inorganic compound was used as Se sources for both seed priming and foliar application. Data regarding physiochemical, antioxidants, and yield components were recorded as response variables at crop maturity. Results indicated that WP, OP, TP, proline, TSS, TFAA, TPr, TS, total chlorophyll contents, osmoprotectant (GB, anthocyanin, TPC, and flavonoids), antioxidants (APX, SOD, POD, and CAT), and yield components (number of branches per plant, thousand seed weight, seed, and biological yields were significantly improved by foliar Se + priming Se in both crops under drought stress. Moreover, this treatment was also helpful in boosting yield attributes under irrigated (non-stress) conditions. Camelina genotypes responded better to Se application as seed priming and foliar spray than canola for both years. It has concluded that Se application (either foliar or priming) can potentially alleviate adverse effects of drought stress in camelina and canola by eliciting various physio-biochemicals attributes under drought stress. Furthermore, Se application was also helpful for crop health under irrigated condition.     

Ferroptosis: A New Road towards Cancer Management

Ferroptosis is a recently described programmed cell death mechanism that is characterized by the buildup of iron (Fe)-dependent lipid peroxides in cells and is morphologically, biochemically, and genetically distinct from other forms of cell death, having emerged to play an important role in cancer biology. Ferroptosis has significant importance during cancer treatment because of the combination of factors, including suppression of the glutathione peroxidase 4 (Gpx4), cysteine deficiency, and arachidonoyl (AA) peroxidation, which cause cells to undergo ferroptosis. However, the physiological significance of ferroptosis throughout development is still not fully understood. This current review is focused on the factors and molecular mechanisms with the diagrammatic illustrations of ferroptosis that have a role in the initiation and sensitivity of ferroptosis in various malignancies. This knowledge will open a new road for research in oncology and cancer management.     

Redox behavior of juglone in buffered aq.: Ethanol media

The present work reports the redox mechanism of 5-hydroxynaphthalene-1,4-dione (HND), commonly known as juglone, in buffered aqueous media having 50% of ethanol. HND followed different mechanistic routes depending upon the pH of the media and more than one pK_a were evaluated from the changes in the slope of the E_p vs. pH plot. The change of pH from acidic to neutral conditions was found to switch the mechanism from CEC to EE mechanism. Pulse techniques were utilized to determine the number of electrons involved in the oxidation and/or the reduction step and to ensure the nature of the redox process. Based upon the obtained results, an electrode reaction mechanism was proposed. Computational studies of HND supported the experimental results. UV-Visible spectroscopy was also employed for the detailed characterization of the compound in a wide range of pH and for the determination of its pK_a.     

In Vivo Antistress Effects of Synthetic Flavonoids in Mice: Behavioral and Biochemical Approach

Natural flavonoids, in addition to some of their synthetic derivatives, are recognized for their remarkable medicinal properties. The present study was designed to investigate the in vitro antioxidant and in vivo antistress effect of synthetic flavonoids (flavones and flavonols) in mice, where stress was induced by injecting acetic acid and physically through swimming immobilization. Among the synthesized flavones (F1–F6) and flavonols (OF1–OF6), the mono para substituted methoxy containing F3 and OF3 exhibited maximum scavenging potential against DPPH (2,2-diphenyl-1-picrylhydrazyl) with IC₅₀ of 31.46 ± 1.46 μg/mL and 25.54 ± 1.21 μg/mL, respectively. Minimum antioxidant potential was observed for F6 and OF6 with IC₅₀ values of 174.24 ± 2.71 μg/mL and 122.33 ± 1.98 μg/mL, respectively, in comparison with tocopherol. The ABTS scavenging activity of all the synthesized flavones and flavonols were significantly higher than observed with DPPH assay, indicating their potency as good antioxidants and the effectiveness of ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) assay in evaluating antioxidant potentials of chemical substances. The flavonoids-treated animals showed a significant (* p < 0.05, ** p < 0.01 and *** p < 0.001, n = 8) reduction in the number of writhes and an increase in swimming endurance time. Stressful conditions changed plasma glucose, cholesterol and triglyceride levels, which were used as markers when evaluating stress in animal models. The level of these markers was nearly brought to normal when pre-treated with flavones and flavonols (10 mg/kg) for fifteen days in experimental animals. These compounds also considerably reduced the levels of lipid peroxidation (TBARS: Thiobarbituric acid reactive substances), which was significant (* p < 0.05, ** p < 0.01 and *** p < 0.001, n = 8) compared to the control group. A significant rise in the level of catalase and SOD (super oxide dismutase) was also observed in the treated groups. Diazepam (2 mg/kg) was used as the standard drug. Additionally, the flavonoids markedly altered the weight of the adrenal glands, spleen and brain in stress-induced mice. The findings of the study suggest that these flavonoids could be used as a remedy for stress and are capable of ameliorating diverse physiological and biochemical alterations associated with stressful conditions. However, further experiments are needed to confirm the observed potentials in other animal models, especially in those with a closer resemblance to humans. Toxicological evaluations are also equally important.     

Core-shell microgel stabilized silver nanoparticles for catalytic reduction of aryl nitro compounds

Silver nanoparticles loaded into shell of poly (styrene-N-isopropylmethacrylamide-co-acrylic acid) core shell [P (SNA-CS)] gel particles were synthesized and analyzed by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), ultraviolet–visible spectroscopy (UV–vis) and dynamic light scattering (DLS). Catalytic activity of Ag@P (SNA-CS) particles was investigated by reducing p-nitroaniline (p-NA) into p-aminoaniline (p-AA) in the presence of sodium borohydride (NaBH₄) reductant. Molecules of the substrate adsorbed on the surface of silver nanoparticles interact with borohydride ions (BH₄⁻) to form p-AA. Other nitroarenes like o-nitroaniline (o-NA), p-nitrophenol (p-NP) o-nitrophenol (o-NP), 2,4-dinitrophenol(2,4-DNP) were also reduced into their corresponding aryl amines using Ag@P (SNA-CS) composite microgels as catalyst. Reported catalyst efficiently reduced the nitro aromatic compounds individually as well as simultaneously at ambient temperature. Effect of different reaction conditions (catalyst dose, concentration of NaBH₄ and concentration of p-NA) on reaction completion time, value of apparent rate constant (k_app) and reduction efficiency of the catalyst for reduction of p-NA was also demonstrated. Ag@P (SNA-CS) catalyst was found to be able to retain activity up to four cycles.