Latest Research on Disulphide : Dec 2021

Electric-field-induced superconductivity at 9.4 K in a layered transition metal disulphide MoS2

Electro-static carrier doping was attempted in a layered transition metal disulphide MoS2 by constructing an electric double-layer transistor with an ionic liquid. With the application of gate voltage VG higher than 3 V, a metallic behavior was observed in the MoS2 channel. We found an onset of electric field-induced superconductivity in the field induced metallic phase. A maximum TC ∼ 9.4 K was observed, which could be higher than those in chemically doped bulk materials.[1]


A novel oxidative stress marker in patients with Alzheimer’s disease: dynamic thiol–disulphide homeostasis

Objective
The aim of this study was to evaluate the dynamic thiol–disulphide homeostasis as an oxidative stress parameter, using a newly proposed method, in patients with Alzheimer’s disease.

Methods
In total, 97 participants were included in the study. Among them, 51 had been diagnosed with Alzheimer’s disease, and the remaining 46 were healthy individuals. Total thiol (–SH+–S–S–) levels and native thiol (–SH) levels in serum of each participant were measured. The amount of dynamic disulphide bonds (–S–S–) and (–S–S–) ×100/(–SH), (–S–S–) ×100/(–SH+–S–S–), and –SH×100/(–SH+–S–S–) ratios were calculated from these values. The obtained data were used to compare Alzheimer’s disease patients with healthy individuals.

Results
The average total thiol and native thiol levels of patient with Alzheimer’s disease in the study were found to be significantly lower than those levels of healthy individuals. In addition, in the patient group, the –S–S–×100/–S–S+–SH ratio was found to be significantly higher, whereas the –SH×100/–S–S+–SH ratio was found to be significantly lower compared with healthy individuals. Total thiol and native thiol levels, dynamic disulphide bond amount, and –S–S–×100/–SH, –S–S–×100/–S–S+–SH, and –SH×100/–S–S+–SH ratios were not found to be correlated with mini mental state examination score or duration of disease. Conclusion
Recent studies have shown that oxidative stress is the one of the molecular changes underlying the pathogenesis of Alzheimer’s disease. In this study, we have investigated the dynamic thiol–disulphide homeostasis in patients with Alzheimer’s disease, using a novel method.[2]


Evaluation of Mechanical Properties of Aluminium Alloy (Al-2024) Reinforced with Molybdenum Disulphide (MOS2) Metal Matrix Composites

The results of an experimental investigation on the mechanical properties of molybdenum disulphide (MOS2, also called molydisulphide) powders reinforced in aluminium alloy (Al-2024) composite samples are reported in this paper. MOS2 powders of approximately 40 μm particle size were reinforced in an aluminium alloy matrix to produce composite samples of ratios, 1, 2, 3, 4 & 5 weight % through stir casting technique. The fabricated composite specimens were subjected to a series of tests to evaluate the mechanical properties such as hardness and tensile strength. The same are compared with the base alloy. SEM and XRD analysis was carried out to analyze the microstructure and the dispersion of the reinforced particles in the alloy matrix. It was fairly observed from the results that, the hardness and tensile strength increased with the increase in wt. % of reinforcement particles in the matrix up to 4% addition of reinforcement and the hardness and tensile strength decreased for 5% addition of reinforcement in the matrix. The SEM and XRD results revealed the homogeneous dispersion of MOS2 particles in the matrix.[3]


Functional and Evolutionary Genomics of Protein Disulphide Isomerase (PDI) Gene Family in Wheat and Its Wild relatives: A Review

Mature wheat grain contain 8-20% proteins. The storage proteins of wheat determine the characteristics and unique properties of its flour in the process of pasta and bread-making and eventually the quality of the finished products obtained. The storage proteins play an integral role in determining the visco-elastic properties of wheat dough, a feature of high quality wheat. The genes, encoding storage proteins as well as factors that may affect their deposition, such as molecular chaperones and foldase enzymes, are of particular interest to wheat industry. Genomic, cDNA and promoter sequences of the three homoeologous gene encoding the “typical” PDI has been already cloned and characterized. Recently, eight new non-homoeologous wheat genes were cloned and characterized in bread wheat. Study characterizing the variability in a 700 bp region comprising 600 bp of 5’ upstream putative promoter region and 100 bp of the first exon of the typical PDI gene in 15 accessions of Triticum urartu (AA), Aegilops speltoides (BB) and Aegilops taushcii (DD), from diverse origin and Triticum aestivum cv Chinese Spring (AABBDD) has also been completed recently. This review explains how functional and evolutionary genomics tools aid in the study of a gene family and its promoter. [4]


Adsorption Energies of Lithium and Sodium Ions on Vanadium Disulphide: A DFT Study

Various energy sources are utilized at present with a challenge of energy storage in many cases. The existing rechargeable storage batteries which include sodium-ion and lithium-ion batteries have some limitations in their gravimetric capacities. Ab initio methods based on density functional theory (DFT) was used to investigate the adsorption of lithium ions and sodium ions on layered Vanadium disulphide. Metallic VS2 monolayer has a higher theoretical gravimetric capacity of 466mAh/g. This study showed that Sodium adsorbs on monolayer VS2 with lower adsorption energy of -2.00eV compared to Lithium (1.47eV) and it is more stable. [5]


Reference

[1] Taniguchi, K., Matsumoto, A., Shimotani, H. and Takagi, H., 2012. Electric-field-induced superconductivity at 9.4 K in a layered transition metal disulphide MoS2. Applied Physics Letters, 101(4), p.042603.

[2] Gumusyayla, S., Vural, G., Bektas, H., Deniz, O., Neselioglu, S. and Erel, O., 2016. A novel oxidative stress marker in patients with Alzheimer’s disease: dynamic thiol–disulphide homeostasis. Acta neuropsychiatrica, 28(6), pp.315-320.

[3] Rebba, B. and Ramanaiah, N., 2014. Evaluation of mechanical properties of aluminium alloy (Al-2024) reinforced with molybdenum disulphide (MOS2) metal matrix composites. Procedia Materials Science, 6, pp.1161-1169.

[4] Dhanapal, A.P. and Porceddu, E., 2013. Functional and evolutionary genomics of protein disulphide isomerase (PDI) gene family in wheat and its wild relatives: a review. Annual Research & Review in Biology, pp.935-958.

[5] Murila, G.I., Manyali, G.S. and Wafula, H.B., 2019. Adsorption Energies of Lithium and Sodium Ions on Vanadium Disulphide: A DFT Study. Journal of Materials Science Research and Reviews, pp.1-6.


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