Copper nanoparticles catalysed an efficient one-pot multicomponents synthesis of chromenes derivatives and its antibacterial activity

In this study, copper nanoparticles (Cu NPs) were synthesised by using diethylenetriamine as a protective agent in chemical reduction method. The obtained nanoparticles were characterised by various spectroscopic techniques like powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR), UV–visible spectroscopy, energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermal analysis (TG/DTA). The structure and composition were estimated by PXRD, FTIR, EDS, UV–visible and TG/DTA techniques, while particles size and morphology behaviours were investigated by SEM and TEM instrumentation. A noteworthy, average particle size of nanoparticles was found around 40 nm with spherical shapes. Furthermore, the applications part of NPs were studied as a catalyst for one-pot solvent-free green synthesis of 3,4-dihydropyrano[c]chromenes from different aromatic aldehydes, malonitrile and 4-hydroxycoumarin by stirring at 80 °C. Moreover, the antibacterial properties of NPs were assessed in vitro against human bacterial pathogen such as Staphylococcus aureus, Escherichia coli, Klebsiella sp. and Pseudomonas aruginosa using agar well diffusion method. Gram positive bacteria S. aureus (18 mm) exhibited a maximum zone of inhibition at 60 µg/ml of Cu NPs. Nonetheless, antibacterial activities of Cu NPs (10–100 µg) were compared with four well-known antibiotics likes amikacin (30 mcg), ciprofloxacin (5 mcg), gentamicin (5 mcg) and norfloxacin (10 mcg). This study indicates that Cu NPs exhibited a strong antibacterial activity against all the test pathogens even at lower concentration.     

Efficient solar photo-electrochemical hydrogen generation using nanocrystalline CeFeO3 synthesized by a modified microwave assisted method

Pure phase of CeFeO₃ perovskite was synthesized by using a modified microwave-assisted method and was systematically studied by photo-electrochemical (PEC) investigations for water splitting reaction. Characterization studies confirm the formation of crystalline orthorhombic single phase perovskite structure with space group Pbnm and having agglomerated sponge-like morphology with nano size grains. DRS shows broad absorption in UV–Visible region, while tauc plot also inferred estimated band gap of 1.9 eV. The photo-activity of their screen printed thin film was analyzed by PEC studies, which includes photocurrent, EIS spectra, MS-plot, J-V plots. On illumination, EIS analysis of CeFeO₃ reveals improved charge transfer at interfaces of semiconductor/electrolyte. The photocurrent density difference of CeFeO₃ was increased to 6.9 mA cm^?2 at an applied bias of 1.5 V vs (Ag/AgCl). PEC H₂ evolution shows significant cumulative hydrogen rate of 12.3 μmol cm^?2 h^?1. All these results reveal that the microwave-synthesized CeFeO₃ is a potential candidate for PEC application under the visible light illumination.     

Hydrogen Distribution in Nuclear Reactor Containment During Accidents and Associated Heat and Mass Transfer Issues—A Review

Hydrogen generation during the progression of an accident in a nuclear reactor and its release into the containment comprise an important safety concern in the management of severe accidents in nuclear power plants. The distribution of hydrogen within the containment has important bearing on possibility, mode, and consequence of combustion in the containment. Hence, several small- and large-scale facilities have been built to study the distribution of released hydrogen. Further, several numerical studies and intercomparison exercises on hydrogen distribution have been carried out. The present review summarizes the experimental and numerical studies on hydrogen distribution and suggests opportunities for further studies.     

A deformation induced order-disorder transition in isotactic polypropylene

In this study, isotactic polypropylene (i-PP) has been deformed by uniaxial compression to draw ratios up to 16×, and at draw temperatures from 30°C to 140°C. An order-disorder transition in the crystals is observed at draw temperatures well above the stability limit, 70°C, reported for the disordered phase; Furthermore, this disordered phase (called smectic) is found to induce ductility and improve the efficiency of draw. The deformation induced smectic phase has been characterized using WAXS, DSC, and on-line compression load versus draw ratio measurements. In consequence, a set of process conditions are offered to optimize draw. A mechanism for plastic deformation of i-PP is also suggested, using the smectic phase as a probe.     

Herbs-are they safe enough? an overview

Drugs based on herbs have become a common form of therapy as well as for prophylaxis because they are often perceived as being natural and therefore harmless. Today they are one of the hottest trends and most sought after in the field of nutrition or herbal therapeutics. As the use of complementary medicine grows, so does the knowledge that many compounds in common use not only have a significant effect on the body but may also interact with pharmaceuticals and also with other alternative products. Concurrent use of herbs with drugs may mimic, magnify, or oppose the effect of drugs leading to herb-drug interactions. Currently, there is very little information published on herb-herb or herb-drug interactions as compared to the use of herbs which is progressively growing across the world. Many reports of herb-drug interactions are sketchy and lack laboratory analysis of suspect preparations. Health-care practitioners should caution patients against mixing herbs and pharmaceutical drugs. The article reviews the recent literature on the adverse effects of herbal remedies including the most widely sold herbal medicinal products, like liquorice, garlic, ginger, green tea, and turmeric, etc., and reinforce the safety aspect of herbal products, which are considered to be relatively safe by common people.