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The aqueous sodium-ion battery is a promising alternative to the well-known lithium-ion battery owing to the large abundance of sodium ion resources. Although it is safer than the lithium-ion battery, the voltage window of the sodium-ion battery is narrower than that of the lithium-ion battery, thus limiting its practical implementation. Therefore, a highly concentrated electrolyte is required to address this issue. In the present work, the effect of the salt concentration on the transport properties of water molecules is investigated via theoretical analyses at the quantum mechanical level. A molecular dynamics simulation at the quantum mechanical level revealed that as the salt concentration increases, the ion–water interactions became stronger, leading to a lower diffusivity and a lower electronic band gap. These imply that the superconcentrated aqueous-based electrolytes have high potentials for the sodium-ion battery applications.

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Lithium batteries development are triggered so many efforts in producing electronic devices due to its excellent performance as energy storage systems. One of the appealing points solid polymer electrolytes for developing solid-state lithium batteries. In this study, Solid polymer electrolytes with crosslinked treatment (SPE-C) were prepared from carboxymethyl cellulose-lithium perchlorate (CMC-LiClO4) and citric acid (CA) as a crosslinker via solution casting method. All SPE-C membranes were assembled into lithium battery coin cells. Degree of crosslinked and degradation were measured to observe crosslink formation in SPE-C membranes and confirmed by fourier transform infrared (FTIR), whereas SPE-C in coin cells were characterized by electrochemical impedance spectroscopy (EIS) and linear sweep voltammograms (LSV). The results showed that crosslinked process is successfully obtained with C=O from ester linkage of CA vibration within COO- of CMC for the crosslinking bond formation. The crosslink effect also contributed on enhancing ionic conductivities of SPE-C in coin cells from EIS results. The highest ionic conductivity was obtained in SPE-C2 (1.24×10-7 S/cm) and electrochemically stable in 2.15 V based on LSV measurement. SPE-C2 has good dielectric behavior than the others due to the high ions mobilities for migration process from ion clusters formation, thus it would be useful for further study in obtaining the powerful solid-state lithium polymer batteries.

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A novel thioesterse gene was successfully cloned and sequenced directly from natural sample of Domas Hot Spring, West Java, Indonesia. Homological analysis of the sequence showed that the gene appeared high homology to thioesterase genes with the highest to a putative thioesterase gene from uncultured Acidilobus sp. JCHS at 66% identity. However, phylogenetic analysis showed that the protein was separated from the branch with other known thioesterases. The size of the gene is around 500 base pairs, lied into 2 kb DNA fragment from a random PCR amplicon. The gene was overexpressed in Escherichia coli , a dominant band appeared at 17 kDa in SDS-PAGE with expression level at around 32% of total proteins. The activity of the purified protein using acetyl-CoA as substrate showed that the protein exhibited thioesterase activity. Furthermore, the enzyme also showed esterase activity on p-nitrophenyl ester as substrate. Detail characterization of esterolytic activity showed that the enzyme preferred p-nitrophenyl decanoate as substrate. The optimum activity of the enzyme was at 80 °C and pH 8. Activity of the enzyme was maintained after incubation at 80 °C up to 24 h. In addition, the enzyme was favorable on polar organic solvents. All the data obtained suggested that the enzyme is a novel alkaline thermostable thioesterase.

Skin aging is a condition caused by reactive oxygen species (ROS) and advanced glycation end products (AGEs). Indonesian gingers (Zingiber officinale), which consists of Gajah (GG), Red (MM), and Emprit (EE) ginger, are thought to produce anti-skin aging compounds through enzyme inhibition. The enzymes used in the molecular docking study were collagenase, hyaluronidase, elastase, and tyrosinase. This study aimed to determine the compounds contained in Indonesian ginger rhizome ethanolic extracts using liquid chromatography–mass spectrometry/mass spectrometry to differentiate metabolites contained in the different Indonesian ginger rhizome extracts. A principal component analysis (PCA) and a heat map analysis were used in order to determine which compounds and extracts contained potential anti-skin aging properties based on a molecular docking study. Ascorbic acid was used as a control ligand in the molecular docking study. Ninety-eight compounds were identified in three different ginger rhizomes extracts and were grouped into three separate quadrants. The most potent compound for anti-skin aging in the Indonesian ginger rhizome extracts was octinoxate. Octinoxate showed a high abundance in the EE ginger rhizome extract. Therefore, the EE ginger extract was the Indonesian ginger rhizome extract with the greatest potential for anti-skin aging.

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