Current Perspectives on Chemical Sciences Vol. 9

This study aimed to find the characteristics of mechanical, morphological, and thermal properties of poly(vinyl alcohol) (PVA)/ bentonite nanocomposites. The method used in making nanocomposites is a sol-gel method. The natural bentonite (size of 35.26 nm) obtained from North Sumatra, Indonesia, was added to the solution of poly(vinyl alcohol) with the quantity varied, namely 0, 2, 4, 6, 8 wt %. The nanocomposites yielded were then characterized by using tensile test, scanning electron microscopy, and differential scanning calorimetry. The results showed that the maximum weight of added bentonite, which improved the mechanical properties and produced a more homogenous surface, was 6 wt %, whereas the variation of 2, 4, and 8 wt % of bentonite resulted in a decreased elasticity modulus. However, thermal properties are preferable to improve in the 0 wt % of bentonite.

Natural compounds play very important role in drug development. Natural extracts from plants have been used for several years for different purposes and now a days uses as alternative remedies and food preservatives. In recent years, a great significant attention has been drawn to natural compounds rather than synthetic compounds due to their less side effects or without side effects in therapeutic. Present work deals with chemical composition & in vitro antibacterial activity of methanolic extracts of five ginger accessions collected from different places of Uttarakhand. Molecular docking is performed between phytocompounds identified through GC-MS analysis and bacterial protein PDB ID: 1QFE and PDB ID: 2VF5. By comparing the scoring results of compositions in extracts of ginger rhizome with bacterial protein, we can infer antibacterial activity about selected phytocompounds. Molecular-docking analysis and antimicrobial test proved that methanolic extract of ginger accession  from Dharchula had strong antibacterial effects. However, despite their potential, the use of natural antimicrobials in food systems remains limited mainly due to the side effects of undesirable flavor or aroma. Therefore, further research is needed to determine the optimum levels of antibacterials that can be safely applied in food systems without unduly altering any sensory characteristics.

Millets are climate-resilient crops adapting to wide range of ecological conditions requiring less irrigation with better growth and productivity in low nutrient input conditions depending minimal on artificial fertilizers and vulnerability to environmental stresses. The nutritionally superior millets are still confined to the traditional consumers and populations of lower economic strata. There is need to revive the importance of millet groups as health foods to enhance food and nutritional security. Millets due to their nutritive value have potential health benefits to prevent cancers, decrease the occurrence of cardiovascular diseases, reduce tumor proliferation, lower blood pressure, risk of heart diseases, cholesterol content, rate of fat absorption, delayed gastric emptying and increased gastrointestinal bulk. Value-addition to millet grains as ready-to-eat and ready-to-cook items offers good opportunity to farmers for enhanced income generation, promotes production and marketing leading to nutritional security, employment and revenue generation. These are nutritious with health benefits requiring significantly lesser inputs and cost of cultivation along with naturally being tolerant to most biotic and abiotic stresses. These features of millets accentuate them as crops of choice in the present scenario.

Duplex stainless steels with varying chromium content are taken and subject to heat treatment between the temperatures ranges of 900 to 1000°C to understand the phase stability of ferrite at such elevated temperatures. It is well observed that, ferrite is the active phase in duplex stainless steel as the austenite grains remains unchanged after heat treatment. Also, formation of sigma in ferrite phases affects the toughness of the material, even though austenite is present in large amount. It is also observed that, higher the aging temperature, higher is the kinetics of formation sigma phase in duplex stainless steel. In addition to Cr, Mo increases the affinity of formation of sigma phase.

The impetus behind this effort centers upon the improvement of a more robust understanding of the microstructural qualities, materials surface, and bulk chemistry, as well as properties of cold sprayed conventional copper and nanostructured copper coatings, in so far as they relate to antipathogenic contact killing and inactivation applications. Therefore, the role of high strain rate induced severe plastic deformation states, microstructures, electrochemical behaviors, surface chemistry, and surface roughness were characterized for two copper cold spray material consolidations, which were produced from conventionally gas-atomized copper powder as well as a nano-agglomerated and spray-dried copper feedstock powder, during this work. Prior work has revealed greater antipathogenic efficacy concerning the respective nanostructured Cu coating versus the conventional Cu coating. Thus, the microstructural analysis was performed to establish differences between the two coatings such that their respective pathogen killing and/or inactivation rates could be deductively and experimentally attributed to. Results from advanced laser-induced projectile impact testing, X-ray diffraction, scanning electron microscopy, electron backscatter diffraction, scanning transmission microscopy, nanoindentation testing, energy-dispersive X-ray spectroscopy, confocal microscopy, atomic force microscopy, linear polarization, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, and copper ion release assessment, among other experimental methods, were performed and pursued during the research and results considered herein.

In present report novel oxazine were prepared from starting materials chalcone and urea (1). The resulting compound 6-(4-chlorophenyl)-4-phenyl-6H-1,3-Oxazin-2-amine(2) was further reacted with ethyl 2-cyano-3,3-bis (methylthio) acrylate in the presence of catalytic amount of potassium carbonate in DMF under reflux condition that offered novel 2-(4-chlorophenyl)-8-(methylthio)-6-oxo-4-phenyl-4,6,9,9 a-tetrahydropyrimido[2,1-b][1,3]oxazine-7- carbonitrile (3). The synthesized compounds were characterized by spectral methods. The compound (3) possesses replaceable methylthio (-SCH₃) group at 8 position. The compound (3) react with various nucleophiles like substituted aromatic amines, aromatic phenols, hetryl amines and active methylene compounds to give 2-(4- chlorophenyl)-8-(substituted)-6-oxo-4-phenyl-4,6,9,9a-tetrahydropyrimido[2,1-b][1,3] oxazine-7-carbonitrile in good yields. In compound (3) cyano and thiomethyl groups are at adjacent position it also undergoes cyclization to give polycyclic heterocyclic compound.

Practical activities are an essential component of science teaching and learning. Nowadays the majority of school laboratories is well equipped with experimental devices and computer based experiment systems (Vernier, Pasco). The key question of our research is, whether using all this equipment make teaching physics more effective. The aim of the paper is to discuss the efficiency of laboratory work and experiments provided by teachers so as by learners at various types of schools. Physics is an experimental science and laboratory work is the most important way how to verify the theoretical concepts. Students so as researchers must have an opportunity to judge their ideas. What strategies within the use of experiments we need to develop or enrich students´ scientific knowledge? Examples how to design learning outcomes of hands on experiments so as computer based experiments in the content of school curricula will be presented.

In the periodic table of elements, indium is located within group 13, and has the atomic number 49. Indium is classified as one of the chemical elements of post-transition metals. Indium is silvery-white in color, soft, and possesses a high level of malleability. Although indium is a relatively rare element, it is indispensable in industry applications worldwide. German metallurgists discovered indium in 1863. It was not until the early 1990s, however, that scientists in the field of synthetic organic chemistry attempted genuine studies to explore the roles of indium or indium-related reagents. Focusing on indium or indium-related reagents, many recent investigations have led to significant advances in synthetic organic chemistry. Various applications have been examined and a growing number of useful chemical transformations using indium or indium-related reagents are being revealed and reported. Chemical transformations of the reactive functional groups are an essential point, particularly for the successful implementation of a sequence of multiple-step chemical schemes. For this purpose, a variety of strategic reaction methodologies have been developed, including those utilizing indium or indium-related reagents. Indium metal was discovered to be useful for the protection and deprotection of functional groups, while trivalent indium Lewis acids have been effective in a wide variety of chemical transformations. This chapter describes an efficient oxone-mediated esterification of aldehydes using indium(III) triflate, which is also one of the trivalent indium Lewis acids. Esterification is performed primarily on aromatic and heterocyclic aldehydes. The results show the effectiveness of this esterification methodology and suggest the potential in the further development of these reagents, which could enhance the field of synthetic organic chemistry.

In the present investigation, an attempt was made to synthesise different compositions of PVA/gelatin hydrogels by gamma irradiation technique. A mixture of PVA and gelatin aqueous solutions of similar concentration at different weight ratios namely, 100/0, 75/25, 50/50, 25/75, and 0/100 respectively and exposed to gamma irradiation dose of 25 kGy. Further, the prepared sample were analysed for structural and morphological characteristics using powder XRD and FESEM analysis respectively. Significant changes in the structural and morphological characteristics were observed for different PVA and gelatin concentration. The swelling studies were carried out at different pH values and the swelling data was fitted to power law expression to know the swelling mechanism of the PVA/gelatin hydrogels. The swelling characteristics of PVA/gelatin hydrogels found to increase with gelatin percentage. The PVA/gelatin hydrogels of different concentrations exhibited better swelling ability with tailored functionalities making them a better material for various biomedical applications. The overall result obtained signifies that the PVA/gelatin hydrogels could be used for various biomedical applications such as wound dressing and drug delivery systems.

In this paper, we discuss the equilibrium properties of Coulomb glass in two and three dimensions. We have used Monte Carlo simulation to obtain various thermodynamic properties. The system is annealed from a temperature much greater than than the transition temperature to very small temperatures below it. At small disorders our results differ from other simulations. The critical exponents are different at small disorders from the short range random field Ising model.

A new approach to solving systems of linear partial differential equations of the first order has been offered. We use the methods of simultaneous reduction of several matrices. Sometimes, this allows to get an analytical solution or to significantly simplify the problem.

Synthesis of novel thiadiazoles is one of the important aspects in the development of therapeutic drugs. Emphasizing the properties of the new compounds having potential novel structural features and biological applications have been current research in medicinal chemistry. In this connection, here reporting the synthesis and characterization of 5-[substituted]-1, 3, 4-thiadiazol-2-amines (1-7). All the prepared compounds were characterized by spectroscopic methods viz.¹H-NMR, ¹³C{¹H}-NMR, FT-IR, and LC-MS. The DNA binding interactions of the 1,3,4-thiadiazoles were undertaken by absorption and fluorescence spectroscopy methods. The results reveal that the compounds are avid binders to DNA via. Groove binding mode. The DNA cleavage studies of the compounds were carried out in presence and absence of H₂O₂ using gel electrophoresis.