Rheological and anti-microbial study of silica and silver nanoparticles-reinforced k-carrageenan/hydroxyethyl cellulose composites for food packaging applications

Cellulose - Sustainable food packaging films were developed using a combination of k-Carrageenan (k-C), hydroxyl ethyl cellulose (HEC), silicon dioxide (SiO2), and silver (Ag) nanoparticles. The...     

Comments on “Crystal growth,spectral, optical,and thermal characterization of glycyl-l-alanine hydrochloride (GLAH) single crystal”

The authors of the title paper (J Therm Anal Calorim 2012,110:873–878) report to have grown a dipeptide hydrochloride crystal namely glycyl-l-alanine hydrochloride by the slow evaporation of an aqueous solution containing stoichiometric amounts of l-alanine and glycine and an excess of hydrochloric acid. In this letter, we prove that no such dipeptide hydrochloride can be crystallized simply by mixing two amino acids in aqueous hydrochloric acid.     

Use of surfactant in aniline polymerization with TiO2 to PANI-TiO2 for supercapacitor performance

Polyaniline sulphate salt titanium dioxide composite (PANI-H₂SO₄·TiO₂) was synthesized by chemical in situ polymerization of aniline in the presence of TiO₂. The effect of anionic surfactant (sodium lauryl sulphate) in this reaction was also assessed. During the polymerization reaction, sodium lauryl sulphate (SLS) is converted to dodecyl hydrogen sulphate (DHS) in the presence of acidic medium and gets doped onto polyaniline along with sulphuric acid dopant, i.e. formation of polyaniline-sulphate-dodecyl hydrogen sulphate-titanium dioxide composite (PANI-H₂SO₄-DHS·TiO₂). In the PANI-H₂SO₄-DHS·TiO₂ composite, the presence of DHS is confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDAX) and TiO₂ is confirmed by XRD and EDAX results. In PANI-H₂SO₄-DHS·TiO₂ system, the nanoparticle of TiO₂ (10–20 nm) is uniformly embedded on nanofibres (20–60 nm) of PANI-H₂SO₄-DHS, and some part of PANI-H₂SO₄-DHS·TiO₂ forms core–shell morphology, wherein TiO₂ is in core and PANI-H₂SO₄-DHS in shell forms. Stability of PANI-H₂SO₄-DHS increases due to the incorporation of stable TiO₂. Utility of PANI-TiO₂ composite was carried out in supercapacitor cell system by performing cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopic techniques in 1 M H₂SO₄ solution. Very low values of solution resistance, charge transfer resistance and time constant are obtained between 0.2 and 0.6 V. Initial specific capacitance values for the cell carried out at low and high current densities are found to be 280 and 205 F g^?1, respectively, and after 1,700 charge–discharge cycles, its retention in the specific capacitance values is found to be the same (65–66 %) with coulombic efficiency of 98–100 %. A capacitor can work even at a high discharge rate. The efficiency of oxidizing and doping power increases with the use of a surfactant. Moreover, the use of a long chain surfactant dopant containing polyaniline as an electrode material plays an important role to increase the performance of the supercapacitor by allowing the electrolyte to easily enter and come out from PANI electrodes.     

Electrospun CuFe2O4 nanotubes as anodes for high-performance lithium-ion batteries

Herein,we report on the synthesis and lithium storage properties of electrospun one-dimensional(1D) CuFe_2O_4 nanomaterials.1D CuFe_2O_4nanotubes and nanorods were fabricated by a single spinneret electrospinning method followed by thermal decomposition for removal of polymers from the precursor fibers.The as-prepared CuFe_2O_4 nanotubes with wall thickness of ~50 nm presented diameters of ~150 nm and lengths up to several millimeters.It was found that phase separation between the electrospun composite materials occured during the electrospinning process,while the as-spun precursor nanofibers composed of polyacrylonitrile(PAN),polyvinylpyrrolidone(PVP) and metal salts might possess a core-shell structure(PAN as the core and PVP/metal salts composite as the shell) and then transformed to a hollow structure after calcination.Moreover,as a demonstration of the functional properties of the 1D nanostructure.CuFe_2O_4 nanotubes and nanorods were investigated as anodes for lithium ion batteries(LIBs).It was demonstrated that CuFe_2O_4 nanotubes not only delivered a high reversible capacity of ~816 mAh·g~(-1) at a current density of 200 mA·g~(-1)over 50 cycles,but also showed superior rate capability with respect to counterpart nanorods.Probably,the enhanced electrochemical performance can be attributed to its high specific surface areas as well as the unique hollow structure.     

Hepatoprotective Effect of β-Chitosan from Gladius of Sepioteuthis lessoniana Against Carbon Tetrachloride-Induced Oxidative Stress in Wistar Rats

Chitosan has attracted much attention as a biomedical material, owing to its unique biological activities. In this study, hepatoprotective effect of β-chitosan obtained from the gladius of squid Sepioteuthis lessoniana was studied against carbon tetrachloride (CCl₄)-induced oxidative stress and liver injury in rats. The rats that received β-chitosan along with the administration of CCl₄ showed significantly decreased plasma and tissue alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and total cholesterol, triglyceride (TG) and free fatty acid (FFA) contents, whereas the treatment with β-chitosan alone markedly increased rat hepatic and circulatory superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) and reduced glutathione (GSH) levels and decreased the malondialdehyde level. Histopathological observations recommended the marked hepatoprotective effect of β-chitosan. The CCl₄-induced alterations on circulatory and hepatic antioxidant defence system were normalised by β-chitosan, and it could be concluded that the hepatoprotective effect of chitosan may be due to its antioxidant and antilipidemic property. Therefore, β-chitosan could be considered as antihepatotoxic agent.     

Nano-enabled biosensing systems for intelligent healthcare: towards COVID-19 management

Biosensors are emerging as efficient (sensitive and selective) and affordable analytical diagnostic tools for early-stage disease detection, as required for personalized health wellness management. Low-level detection of a targeted disease biomarker (pM level) has emerged extremely useful to evaluate the progression of disease under therapy. Such collected bioinformatics and its multi-aspects-oriented analytics is in demand to explore the effectiveness of a prescribed treatment, optimize therapy, and correlate biomarker level with disease pathogenesis. Owing to nanotechnology-enabled advancements in sensing unit fabrication, device integration, interfacing, packaging, and sensing performance at point-of-care (POC) has rendered diagnostics according to the requirements of disease management and patient disease profile i.e. in a personalized manner. Efforts are continuously being made to promote the state of art biosensing technology as a next-generation non-invasive disease diagnostics methodology. Keeping this in view, this progressive opinion article describes personalized health care management related analytical tools which can provide access to better health for everyone, with overreaching aim to manage healthy tomorrow timely. Considering accomplishments and predictions, such affordable intelligent diagnostics tools are urgently required to manage COVID-19 pandemic, a life-threatening respiratory infectious disease, where a rapid, selective and sensitive detection of human beta severe acute respiratory system coronavirus (SARS-COoV-2) protein is the key factor.     

Maximum entropy-based variational multiscale element-free Galerkin methods for scalar advection–diffusion problems

Journal of Thermal Analysis and Calorimetry - This paper presents a new parameter-free stability term via Galerkin mesh-free scheme to solve the multiscale behavior of steady-state...     

Sulfur Transfer Reactions of Tetrathiomolybdate in Water: Synthesis of Alkyl Disulfides from Alkyl Halides

Abstract: Reaction of a number of alkyl halides with tetrathiomolybdate in water as the solvent affords the corresponding disulfides in good yields.     

One‐pot direct synthesis of fluorescent polyaniline‐porphyrin macrospheres from porphyrin

Porphyrins are very important chromophores as sensitizer in solar cell. Hole and electron transport layers are being used as an important layer to move the electrons and holes away from the sensitizer molecule to electrodes. In this work, a simple process has been developed for the synthesis of one layer combination of sensitizer and hole transport, that is, polyaniline‐porphyrin (PANI‐TPPS₄) system as a bulk heterojunction. Macrospheres of fluorescent PANI‐TPPS₄ materials were synthesized by one‐pot as well as two step processes directly from porphyrin for the first time. The advantage of this process is no need to isolate sulfonated porphyrin (TPPS₄), which is a difficult process. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Electrochemical characterization of copper chemical mechanical polishing in l-glutamic acid–hydrogen peroxide-based slurries

The effect of l-glutamic acid as complexing agent in the presence of hydrogen peroxide as oxidizer in copper chemical mechanical polishing (CMP) slurry is investigated. In the CMP process, the work surface is moved against a pad, with slurry flowing between the surface and the pad. The polish rate was found to be stable over a wide range of hydrogen peroxide concentration. High concentration of either l-glutamic acid or hydrogen peroxide leads to a reduction in polish rate, but a high concentration of both chemicals does not reduce the polish rate. In the absence of hydrogen peroxide, the Cu polish rate was 0 for all the l-glutamic acid concentrations investigated. However, potentiodynamic polarization curves do not show any sign of passivation when l-glutamic acid was present in the solution. In situ open circuit potential measurements show that copper redox reactions as well as hydrogen peroxide redox reactions contribute in determining the electrochemical behavior. We propose that l-glutamic acid inhibits the copper dissolution by adsorption onto the metallic copper, but enhances copper dissolution by complexing copper ions. The results show that it is possible to conduct controllable copper CMP in mildly acidic slurries with hydrogen peroxide as oxidizer and l-glutamic acid as complexing agent.