An efficacy of ‘nano’ in brannerite-type CoV2O6 conversion electrode for lithium batteries

Among the classical anodes, conversion anodes play a unique role due to their capability to provide initial discharge capacity that is higher than the theoretical capacity.

Tweaking Electrical and Dielectric Properties of Nickel Oxide Nanocrystals by Varying the Surfactant

The influence of cationic cetyltrimethylammonium bromide (CTAB) and neutral polymeric polyvinylpyrrolidone (PVP) surfactants on electrical and dielectric properties of NiO nanocrystals is investigated. It is demonstrated that, compressive strain of nanocrystals is higher with PVP than that of CTAB. Consequently surfactant type has significant influence on intrinsic defects of nanocrystals. This is attributed to the difference in stabilization of metallic ions against agglomeration that leads to variation in rate of hydrolysis. Particularly, in the case of PVP assisted synthesis, higher stabilization leads to slow nucleation rate with lower defect density. As a result the hopping time of charge carriers decreases which in turn enhances the conductivity of nanocrystals as evidenced from the shifting of dielectric loss peak to higher frequency.

Stability and Hopf bifurcation analysis of a diffusive predator–prey model with Smith growth

In this paper, we consider a diffusive Holling–Tanner predator–prey model with Smith growth subject to Neumann boundary condition. We analyze the local stability, existence of a Hopf bifurcation at the co-existence of the equilibrium and stability of bifurcating periodic solutions of the system in the absence of diffusion. Furthermore the Turing instability and Hopf bifurcation analysis of the system with diffusion are studied. Finally numerical simulations are given to demonstrate the effectiveness of the theoretical analysis.

Polyamine metabolism influences antioxidant defense mechanism in foxtail millet (Setaria italica L.) cultivars with different salinity tolerance

KEY MESSAGE

Polyamines can regulate the expression of antioxidant enzymes and impart plants tolerance to abiotic stresses. A comparative analysis of polyamines, their biosynthetic enzymes at kinetic and at transcriptional level, and their role in regulating the induction of antioxidant defense enzymes under salt stress condition in two foxtail millet (Setaria italica L.) cultivars, namely Prasad, a salt-tolerant, and Lepakshi, a salt-sensitive cultivar was conducted. Salt stress resulted in elevation of free polyamines due to increase in the activity of spermidine synthase and S-adenosyl methionine decarboxylase enzymes in cultivar Prasad compared to cultivar Lepakshi under different levels of NaCl stress. These enzyme activities were further confirmed at the transcript level via qRT-PCR analysis. The cultivar Prasad showed a greater decrease in diamine oxidase and polyamine oxidase activity, which results in the accumulation of polyamine pools over cultivar Lepakshi. Generation of free radicals, such as O 2 (·-) and H2O2, was also analyzed quantitatively. A significant increase in O 2 (·-) and H2O2 in the cultivar Lepakshi compared with cultivar Prasad was recorded in overall pool sizes. Further, histochemical staining showed lesser accumulation of O 2 (·-) and of H2O2 in the leaves of cultivar Prasad than cultivar Lepakshi. Our results also suggest the ability of polyamine oxidation in regulating the induction of antioxidative defense enzymes, which involve in the elimination of toxic levels of O 2 (·-) and H2O2, such as Mn-superoxide dismutase, catalase and ascorbate peroxidase. The contribution of polyamines in modulating antioxidative defense mechanism in NaCl stress tolerance is discussed.

Investigations on the rate performance of LiFePO4/CeO2 composite materials via polyol technique for rechargeable lithium batteries

Surface modification of LiFePO₄ using CeO₂ cathode materials has been prepared by polyol technique with a chemical combination route. CeO₂ has been formed as solid solution on LiFePO₄ surface, which provides better EC performances.

Influence of alkaline mineralizer on structural and optical properties of ZrO2 nanoparticles

In this work, the influence of different alkaline mineralizers on structural and optical properties of zirconia nanoparticles synthesized by chemical co-precipitation technique using zirconium oxychloride octahydrate (ZrOCI2 x 8H2O) as precursor is studied. The mineralizers used for the synthesis of nanoparticles are NaOH and NH4OH. X-ray diffraction, Fourier Transform Infrared (FTIR) spectroscopy, UV-visible absorption spectroscopy and Photoluminescence (PL) spectroscopy were used for characterizing the nanoparticles. Structural analysis of the sample synthesized using NaOH shows monoclinic phase as predominant one, however when NH4OH is used the major phases are cubic and tetragonal. The difference is attributed to the number of hydroxyl ions produced and their rate of release during the reaction process. The presence of these phases in both samples is further confirmed by vibrational bands of FT-IR spectra. Also, the low energy bands due to the presence of defects in nanoparticles are also explicitly observed in the photoluminescence spectra. Further the defects lead to a red shift in the band gap of ZrO2 which is observed when the samples are subjected to UV-absorption spectroscopy analysis. It has been demonstrated that zirconia nanoparticles with desired structural properties can be synthesized by changing the type of mineralizer without the necessity of doping.

Study of metallic fibrous nanoparticle aggregate produced using femtosecond laser radiation under ambient conditions

In this study, we report formation of weblike fibrous nanoparticle aggregate due to irradiation of bulk iron, aluminium and titanium samples using femtosecond laser radiation at MHz pulse repetition frequency in air at atmospheric pressure. Electron microscopy analysis revealed that the nanostructure is formed due to aggregation of polycrystalline nanoparticles of the respective constituent materials. The nanoparticle diameter varies between 5 and 40 nm and they are covered with an oxide layer of a few nanometres thick. X-ray diffraction and micro-Raman analysis revealed metallic and oxide phases in the nanostructure. The formation of a nanoparticle aggregate is explained by nucleation and condensation of vapour in the plasma plume and by phase explosion. Moreover the laser interaction time plays a significant role in the generation of nanostructure from bulk metals. This study provides evidence that femtosecond laser irradiation can be an ambient condition physical method for metallic fibrous nanoparticle aggregate generation.

Synthesis of Nanoscale Tips Using Femtosecond Laser Radiation under Ambient Condition

We report a unique growth of platelet-shaped nanoscale tips of transparent dielectric using femtosecond laser radiation at MHz pulse repetition rate with nitrogen background gas flow under ambient condition. The tips grew with sharp nanoscale apex while their base and lengths are of the order of few hundred nanometers. In the absence of nitrogen, the irradiation leads to nanofibrous structure formation. The collision between the nitrogen gas atoms and the vapor species slows down plume expansion and lead to an increase of nanoparticles size. This prevents the fibrous structure formation and provides appropriate condition for nanoscale tips growth.

Synthesis of Glass Nanofibers Using Femtosecond Laser Radiation Under Ambient Condition

We report the unique growth of nanofibers in silica and borosilicate glass using femtosecond laser radiation at 8 MHz repetition rate and a pulse width of 214 fs in air at atmospheric pressure. The nanofibers are grown perpendicular to the substrate surface from the molten material in laser-drilled microvias where they intertwine and bundle up above the surface. The fibers are few tens of nanometers in thickness and up to several millimeters in length. Further, it is found that at some places nanoparticles are attached to the fiber surface along its length. Nanofiber growth is explained by the process of nanojets formed in the molten liquid due to pressure gradient induced from the laser pulses and subsequently drawn into fibers by the intense plasma pressure. The attachment of nanoparticles is due to the condensation of vapor in the plasma.

Peritoneal dialysis in a patient with neurogenic bladder and chronic kidney disease with ventriculoperitoneal shunt

Long-term dialysis in children with multiple handicaps has become easier with the advent of continuous ambulatory peritoneal dialysis (PD). Due to the widespread use of PD and the long survival of patients with spina bifida, an increasing number of patients with spina bifida are on PD. The viability and safety of PD in spina bifida patients with a ventriculoperitoneal shunt (VPS) have been a matter of concern. Some authors consider the presence of a VPS a relative contraindication for PD, but more recent reports suggest that PD under close monitoring is not contraindicated. We report a 17-year-old girl born with meningomyelocele, hydrocephalus and neurogenic bladder who was maintained on VPS. She reached end-stage renal failure 17 years later and was put on PD based on family and patient preference. She had an uneventful course in the initial 9 months, but later developed fungal peritonitis which was successfully managed with catheter withdrawal and an intravenous antifungal agent (amphotercin 0.75 mg/kg). Simultaneous ventricle-aspirated cerebrospinal fluid was sterile. To our knowledge, this is the first report of fungal infection in such a patient. Although we share the view that PD is not an absolute contraindication in patients with a functioning VPS, its likely complications, especially infectious complications in developing countries, should be kept in mind before initiating PD in such patients.

Comparison of artificial neural network and regression models in the prediction of urban stormwater quality

Urban stormwater quality is influenced by many interrelated processes. However, the site-specific nature of these complex processes makes stormwater quality difficult to predict using physically based process models. This has resulted in the need for more empirical techniques. In this study, artificial neural networks (ANN) were used to model urban stormwater quality. A total of 5 different constituents were analyzed-chemical oxygen demand, lead, suspended solids, total Kjeldahl nitrogen, and total phosphorus. Input variables were selected using stepwise linear regression models, calibrated on logarithmically transformed data. Artificial neural networks models were then developed and compared with the regression models. The results from the analyses indicate that multiple linear regression models were more applicable for predicting urban stormwater quality than ANN models.

Reduced mitochondrial coenzyme Q10 levels in HepG2 cells treated with high-dose simvastatin: A possible role in statin-induced hepatotoxicity?

Lowering of low-density lipoprotein cholesterol is well achieved by 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins). Statins inhibit the conversion of HMG-CoA to mevalonate, a precursor for cholesterol and coenzyme Q10 (CoQ10). In HepG2 cells, simvastatin decreased mitochondrial CoQ10 levels, and at higher concentrations was associated with a moderately higher degree of cell death, increased DNA oxidative damage and a reduction in ATP synthesis. Supplementation of CoQ10, reduced cell death and DNA oxidative stress, and increased ATP synthesis. It is suggested that CoQ10 deficiency plays an important role in statin-induced hepatopathy, and that CoQ10 supplementation protects HepG2 cells from this complication.