Active material and interphase structures governing performance in sodium and potassium ion batteries.

Development of energy storage systems is a topic of broad societal and economic relevance, and lithium ion batteries (LIBs) are currently the most advanced electrochemical energy storage systems. However, concerns on the scarcity of lithium sources and consequently the expected price increase have driven the development of alternative energy storage systems beyond LIBs. In the search for sustainable and cost-effective technologies, sodium ion batteries (SIBs) and potassium ion batteries (PIBs) have attracted considerable attention. Here, a comprehensive review of ongoing studies on electrode materials for SIBs and PIBs is provided in comparison to those for LIBs, which include layered oxides, polyanion compounds and Prussian blue analogues for positive electrode materials, and carbon-based and alloy materials for negative electrode materials. The importance of the crystal structure for electrode materials is discussed with an emphasis placed on intrinsic and dynamic structural properties and electrochemistry associated with alkali metal ions. The key challenges for electrode materials as well as the interface/interphase between the electrolyte and electrode materials, and the corresponding strategies are also examined. The discussion and insights presented in this review can serve as a guide regarding where future investigations of SIBs and PIBs will be directed.

The impacts of COVID-19 lockdown on wildlife in Deccan Plateau, India.

The outbreak of the COVID-19 pandemic brought unprecedented changes in human activity via extensive lockdowns worldwide. Large-scale shifts in human activities bestowed both positive and negative impacts on wildlife. Unforeseen reduction in the activities of people allowed wildlife to venture outside of forested areas to exploit newfound habitats and increase their diurnal activities. While on a negative note, a reduction in forest-related law enforcement led to substantial increase in illegal activities such as poaching. We conducted mammal surveys in forested and nearby farmland of a fragmented landscape under two distinct scenarios: pre-lockdown and lockdown. An increase in poaching activities observed during the lockdown period in our study area provided us an opportunity to investigate the impact of the lockdown on wildlife. Camera trapping data of four highly poached mammalian species, namely black-naped hare Lepus nigricollis, wild pig Sus scrofa, four-horned antelope Tetracerus quadricornis and leopard Panthera pardus were considered to investigate activity patterns and habitat use, to understand the effect of lockdown. The pre-lockdown period was used as a baseline to compare any changes in trends of activity patterns, habitat use and detection probabilities of targeted species. Species-specific changes in activity patterns of study species were observed, with an increment in daytime activity during lockdown. The results showed species-specific increase in the habitat use of study species during lockdown. Reduction in the detection probability of all study species was witnessed. This is the first study to highlight the effect of the COVID-19 lockdown on the responses of wildlife by considering the changes in their temporal and spatial use before and during lockdown. The knowledge gained on wildlife during reduced human mobility because of the pandemic aid in understanding the effect of human disturbances and developing future conservation strategies in the shared space, to manage both wildlife and humans.

Genetic manipulation of anti-nutritional factors in major crops for a sustainable diet in future.

The consumption of healthy food, in order to strengthen the immune system, is now a major focus of people worldwide and is essential to tackle the emerging pandemic concerns. Moreover, research in this area paves the way for diversification of human diets by incorporating underutilized crops which are highly nutritious and climate-resilient in nature. However, although the consumption of healthy foods increases nutritional uptake, the bioavailability of nutrients and their absorption from foods also play an essential role in curbing malnutrition in developing countries. This has led to a focus on anti-nutrients that interfere with the digestion and absorption of nutrients and proteins from foods. Anti-nutritional factors in crops, such as phytic acid, gossypol, goitrogens, glucosinolates, lectins, oxalic acid, saponins, raffinose, tannins, enzyme inhibitors, alkaloids, ß-N-oxalyl amino alanine (BOAA), and hydrogen cyanide (HCN), are synthesized in crop metabolic pathways and are interconnected with other essential growth regulation factors. Hence, breeding with the aim of completely eliminating anti-nutrition factors tends to compromise desirable features such as yield and seed size. However, advanced techniques, such as integrated multi-omics, RNAi, gene editing, and genomics-assisted breeding, aim to breed crops in which negative traits are minimized and to provide new strategies to handle these traits in crop improvement programs. There is also a need to emphasize individual crop-based approaches in upcoming research programs to achieve smart foods with minimum constraints in future. This review focuses on progress in molecular breeding and prospects for additional approaches to improve nutrient bioavailability in major crops.

Electrochemical studies of a high voltage Na4Co3(PO4)2P2O7-MWCNT composite through a selected stable electrolyte.

Cathode materials that operate at high voltages are required to realize the commercialization of high-energy-density sodium-ion batteries. In this study, we prepared different composites of sodium cobalt mixed-phosphate with multiwalled carbon nanotubes (Na4Co3(PO4)2P2O7-MWCNTs) by the sol-gel synthesis technique. The crystal structure and microstructure were characterized by using PXRD, TGA, Raman spectroscopy, SEM and TEM. The electrochemical properties of the Na4Co3(PO4)2P2O7-20 wt% MWCNT composite were explored using two different electrolytes. The composite electrode exhibited excellent cyclability and rate capabilities with the electrolyte composed of 1 M sodium hexafluorophosphate in ethylene carbonate:dimethyl carbonate (EC:DMC). The composite electrode delivered stable discharge capacities of 80 mA h g-1 and 78 mA h g-1 at room and elevated (55 °C) temperatures, respectively. The average discharge voltage was around 4.45 V versus Na+/Na, which corresponded to the Co2+/3+ redox couple. The feasibility of the Na4Co3(PO4)2P2O7 cathode for sodium-ion batteries has been confirmed in real time using a full cell configuration vs. NaTi2(PO4)3-20 wt% MWCNT, and it delivers an initial discharge capacity of 78 mA h g-1 at 0.2C rate.

Smooth integral sliding mode controller for the position control of Stewart platform.

This paper proposes the application of a new algorithm for the position control of a Stewart platform. The conventional integral sliding mode controller is a combination of nominal control and discontinuous feedback control hence the overall control is discontinuous in nature. The discontinuity in the feedback control is undesirable for practical applications due to chattering which causes the wear and tear of the mechanical actuators. In this paper the existing integral sliding mode control law for systems with matched disturbances is modified by replacing the discontinuous part by a continuous modified twisting control. This proposed controller is continuous in nature due to the combinations of two continuous controls. The desired position of the platform has been achieved using the proposed controller even in the presence of matched disturbances. The effectiveness of the proposed controller has been proved with the simulation results.

Visco-elastic and flow properties of gelatin from the bone of freshwater fish (Cirrhinus mrigala).

The average yield of gelatin from the bone of freshwater fish (Cirrhinus mrigala) was 6.13%. The fluorescence spectra revealed maximum emission at 303 nm indicating the exposure of chromophores to bulk solvent. The amino acid profile of gelatin revealed a higher proportion of glycine and imino acids. The bloom strength of gelled gelatin was 159.8 g. The average molecular weight of fish bone gelatin was 281 kDa as determined by gel filtration technique. The dynamic oscillatory test of gelatin solution as a function of time and temperature revealed gelling and melting temperatures of 8.0 °C and 17.0 °C, respectively. The flow behavior of gelatin solution as a function of concentrations and temperatures revealed non-Newtonian behavior with pseudo-plastic phenomenon. The Herschel-Bulkley and Casson models were found suitable to study the flow behavior. The emulsion capacity (EC) of gelatin was inversely proportional to its concentration.

Nanofibers: effective generation by electrospinning and their applications.

Electrospinning is the most versatile technology in use today, for the generation of polymer nanoscale fibers. The nano materials generated using this technology have a large surface area and are highly porous making it very useful in many applications in diverse fields such as energy storage, healthcare, biotechnology, environmental engineering, defense and security. The production of the fibers and the morphology can be easily controlled by modifications to the processing parameters. The relatively high production rate and simplicity of the setup makes electrospinning highly attractive. This review summarizes the effect of various processing parameters on the effective generation of nanofibers. By simple modifications to the electric field inside the electrospinning chamber the fiber collection can be easily controlled. In addition, the various applications of electrospun fibers in electronic devices, environmental sensors and filters, energy storage, and in biomedicine such as in tissue engineering, drug delivery and enzyme encapsulation are examined and the current research in each field is also explored in this review.

Synthesis, characterization and electrical properties of carbon coated LiCoPO4 nanoparticles.

Lithium cobalt phosphate (LiCoPO4) nanoparticles were synthesized using modified polyol process. Shape and size of LiCoPO4 nanoparticles were controlled by using poly (vinylpyrrolidone) (PVP) stabilizer. Coating of carbon over the LiCoPO4 nanoparticles was done using the resin coating process to enhance its conductivity. XRD and FTIR results respectively confirm the crystalline phase and structure of pure and carbon coated LiCoPO4 nanoparticles. SEM-EDX results confirm size and shape and also the presence of carbon over LiCoPO4 nanoparticles. Electrical conductivity of pure and carbon coated LiCoPO4 nanoparticles were evaluated by analyzing the measured impedance data using the win fit software. More than three orders of conductivity enhancement was observed in carbon coated LiCoPO4 nanoparticles when compared to pure ones. Further, transport properties like temperature dependence conductivity, AC conductivity, dielectric constant and electric modulus studies were made to find out the bulk and relaxation properties of LiCoPO4 nanoparticles.

Chemical modification of catalytic site of lipase from wheat germ: altered structure-activity profile.

Wheat germ lipase (WGL) was inactivated by chemical modification of histidine, serine and carboxyl groups of Asp/Glu residues with diethyl pyrocarbonate (DEPC), phenyl methyl sulfonyl fluoride (PMSF) and 1-ethyl-3-(3-dimethylaminopropyl) carbodi-imide (EDC), respectively. Loss of activity of WGL was concentration dependent of the inhibitor and at 30 mM PMSF most of the activity of the enzyme was lost. The stoichiometry of modification showed one mole of histidine, serine and two moles of carboxyl groups modified per mole of protein. Kinetic measurements indicated that the inhibition of the enzyme was competitive in nature. The modified enzyme was further characterized by far UV-circular dichroic measurements of the secondary structure and fluorescence spectroscopy. PMSF-modified enzyme showed decreased thermal stability, whereas no change was observed in DEPC-modified enzyme as evidenced by differential scanning calorimetry. These studies indicate that histidine, serine and Asp/Glu residues play an important role in the catalytic function of WGL. The mechanism of loss of activity is due to minor conformational change in the microenvironment of the active site rather than the gross conformational change of the molecule itself.

Effect of urea at lower concentration on the structure of papain--formation of a stable molten globule and its characterization.

Effect of lower concentrations of urea on papain was monitored by optical spectroscopy, calorimetry and partial specific volume measurements. At lower concentrations of urea, papain exhibits a different structure and showed an increase in the intensity of circular dichroic (CD) spectra as compared to the native molecule. At lower concentrations (0.2-1.5 M) of urea, binding of 8-anilino-naphthalene sulfonic acid (ANS) to the papain molecule was higher; at 0.5 M, there was about 50% increase in ANS binding. Both calorimetric and spectroscopic studies indicated an increased thermal stability of the molecule at lower concentrations. At 0.5 M urea concentration, the apparent thermal denaturation temperature increased from a control value of 83 +/- 1 degrees C to 86 +/- 1 degrees C. At isopotential conditions, the partial specific volume of papain was found to be higher in presence of lower concentrations of urea, than the native protein or unfolded molecule. The preferential interaction parameter (deltag3/deltag2)(T,mu1,mu3) showed a negative value in the presence of lower concentrations of urea (0.2-2 M), which was maximum at 1 M urea with a value of -0.019 g/g. Above 3 M urea, the preferential interaction parameter was positive.