Thiocarbohydrazide as ``Diamine' to Construct Macrocyclic and Side-Off Compartmental Ligands

New dinuclear complexes of macrocycles/macroacycles/oximeshaving a reactive peripheral thioketo functional group were synthesized using2,6-diformyl-p-cresol as parent compound and thiocarbohydrazide/variousdiamines as side arms. Thioenolization and subsequent coordination to metal ionof the thio-keto sulfur is observed in asymmetric macrocycles and oxime complexes,while it is kept away from the coordination sphere in symmetric macrocycles. Magnetic susceptibility measurements over the range 7–300 K confirm that the copper(II) centersof the symmetric and asymmetric macrocycles are antiferromagnetically coupled, withvalues for the exchange coupling constant J through the phenolate oxygens of -610 to-580 cm^-1, respectively. The ligands and their complexes are found to be excellent fungistatic agents.     

Synthesis and Characterization of Yttria-Stabilized Zirconia (YSZ) Nano-Clusters for Thermal Barrier Coatings (TBCs) Applications

Yttria-stabilized zirconia (YSZ) nano-clusters were synthesized by a sol–gel process. The aim was to produce YSZ powders in order to prepare thick coatings for thermal barrier to be applied on gas turbine engine components. Yttrium nitrate hexahydrate and zirconium oxy-chloride octahydrate were used as a source of zirconium, citric acid was taken as a chelating agent, and ethylene glycol was used as a polysterification agent. The synthesized powders were characterized by X-ray diffraction, transmission electron microscopy, thermo-gravimetric analysis and differential scanning calorimetry, and Raman spectroscopy. Furthermore, parameters were critically analyzed in order to synthesize non-transformable (t′) tetragonal crystal structure, which is the best zirconia phase for high temperature thermal barrier coatings applications. In this regard, tetragonal YSZ nano-clusters were heated in an alumina crucible at a temperature of 1200 °C for 100 h.     

Thermal Aggregation of Bovine Serum Albumin in Conventional Buffers: An Insight into Molecular Level Interactions

We have studied the effect of some conventional buffers, which are used frequently for biological research, on the thermal aggregation behavior of bovine serum albumin (BSA). The aggregation kinetics of BSA in buffer solutions were investigated by using UV–Vis spectroscopy. The buffers include sodium phosphate buffer, TRIS buffer and imidazole buffer at physiological pH (7.4). Dynamic light scattering and scanning electron microscopy have been employed to illustrate the size and morphology of protein aggregates. The molecular level interactions of buffer molecules with BSA was probed by various spectroscopic techniques, including UV–Vis, fluorescence, and circular dichroism. The results of this study reveal that the strong interactions of the buffers with protein’s folded/unfolded structures lead to stabilization/destabilization of BSA. We have also explored the possible binding sites of BSA for these buffers using a molecular docking technique.     

Genotoxic and Cytotoxic Properties of Zinc Oxide Nanoparticles Phyto-Fabricated from the Obscure Morning Glory Plant Ipomoea obscura (L.) Ker Gawl

The study was undertaken to investigate the antioxidant, genotoxic, and cytotoxic potentialities of phyto-fabricated zinc oxide nanoparticles (ZnO-NPs) from Ipomoea obscura (L.) Ker Gawl. aqueous leaf extract. The UV-visible spectral analysis of the ZnO-NPs showed an absorption peak at 304 nm with a bandgap energy of 3.54 eV, which are characteristics of zinc nanoparticles. Moreover, the particles were of nano-size (~24.26 nm) with 88.11% purity and were agglomerated as observed through Scanning Electron Microscopy (SEM). The phyto-fabricated ZnO-NPs offered radical scavenging activity (RSA) in a dose-dependent manner with an IC₅₀ of 0.45 mg mL⁻¹. In addition, the genotoxicity studies of ZnO-NPs carried out on onion root tips revealed that the particles were able to significantly inhibit the cell division at the mitotic stage with a mitotic index of 39.49%. Further, the cytotoxic studies on HT-29 cells showed that the phyto-fabricated ZnO-NPs could arrest the cell division as early as in the G0/G1 phase (with 92.14%) with 73.14% cells showing early apoptotic symptoms after 24 h of incubation. The results of the study affirm the ability of phyto-fabricated ZnO-NPs from aqueous leaf extract of I. obscura is beneficial in the cytotoxic application.     

The renaissance in redox flow batteries

Although redox flow batteries were invented as early as 1954, no system development took place until NASA demonstrated an Fe/Cr redox flow battery system in 1970s. In hibernation for several years, redox flow battery systems have begun to catch the attention of policy makers globally. The resurrection of redox flow batteries rests heavily on their techno-economic feasibility as large-scale energy storage systems for emerging grid network that are being developed by climate change mitigation industries, namely, wind and solar. This article reviews various redox flow battery technologies with a cost and market prognosis.     

Emerging trends in miniaturized and microfluidic electrochemical sensing platforms

Electrochemical sensing has established a strong presence in diverse areas. The conventional electrochemical sensing approach consumes large sample volumes and reagents and requires bulky potentiostat, macro-electrodes, and other equipment. The synergistic integration of electrochemical sensing systems with miniaturized or microfluidic electrochemical devices and microelectrodes in a single platform provides rapid analysis with a disposable, reusable, and cost-effective platform for multiplexed point-of-care detections. Such microdevices have created scope for using several materials as electrodes and sensing platforms by using appropriate fabrication techniques. One of the most recent advancements in miniaturized devices includes the integration of automation and Internet of Things to realize fully automated and robust electrochemical microdevices. The review summarizes the emerging trends in fabrication methods of miniaturized and microfluidic devices, their multiple applications in real-time, integration of Internet of Things, automation, identifying research gaps with strategies for bridging these gaps, future outlook, and recent approaches to intelligent electrochemical sensing.     

Dynamical features of the solid motion in gas–solid risers

The trajectories of a solid tracer with the same characteristics as the circulating solids in the risers of two pilot-scale circulating fluidized beds (CFBs), obtained by the computer automated radioactive particle tracking (CARPT) technique, are examined in detail to get further insights into the complex solids dynamics of these systems. The analysis uses tools from the theory of non-linear dynamics and symbolic dynamics. Distinct features of the solids dynamics within the fast fluidization and the dilute phase transport flow regimes are highlighted and related to the operating conditions. The possibility of downflow cluster existence within the central region of the riser is particularly examined.     

Two new isatin derivatives: 1‐benzyl‐4,5,6‐trimethoxyindoline‐2,3‐dione and 1‐benzyl‐5‐fluoroindoline‐2,3‐dione

Isatin (1H‐indole‐2,3‐dione) derivatives represent synthetically useful substrates which can be used to prepare a broad range of heterocyclic compounds. In the title compounds, C₁₈H₁₇NO₅, (I), and C₁₅H₁₀FNO₂, (II), the isatin ring systems are planar and form a dihedral angle of 73.04 (7)° in (I) and 76.82 (11)° in (II) with the benzyl groups. The bicyclic scaffolds in both compounds are almost superimposable, with an r.m.s. deviation of 0.061 Å. The crystal structures of both derivatives are stabilized by C—H...O interactions. These contacts generate an R¹₂(7) ring motif in (I) and a C(7) chain motif in (II).