Graphene Nanosheets Decorated with Copper Oxide Nanoparticles for the Photodegradation of Methylene Blue

Textile industries extensively use colorants, such as methylene blue, and if disposed off untreated, they contaminate the effluent streams, causing a severe impact on the environment and aquatic life. Photocatalytic degradation has been found as an inevitable approach to treat them. Herein, we decorated the copper oxide nanoparticles on graphene nanosheets during the reflux process. The resultant copper oxide/graphene nanocomposites were analyzed for structural and functional attributes. It was observed that on increasing the copper oxide contents, the z-average size of the resultant nanocomposites decreased. The X-ray diffraction analysis demonstrated the crystalline nature of the nanocomposite. The surface morphology of the copper oxide nanoparticles appeared to be spherical and that of the copper oxide/graphene composite somehow wrinkled. The infrared analysis indicated successful intercalation of precursors in the nanocomposite. The bandgap of copper oxide/graphene nanocomposites varied in the range of 1.03-1.30 eV, which indicated their effective photocatalytic activity. The results demonstrated that after 120 min of exposure, the methylene blue removal efficiency reached 94.0%, 92.2%, and 89.4%(mass fraction) on the copper oxide/graphene nanocomposite at copper oxide nanoparticles to graphene nanosheets ratios of 1:1, 1.5:1, and 2:1 (mass ratio), respectively. The photodegradation performance of the prepared nano-catalyst was found satisfactory even after five cycles.     

Identification of Human Kinin-Forming Enzyme Inhibitors from Medicinal Herbs

The goal of this study was to assess the pharmacological effects of black tea (Camellia sinensis var. assamica) water extract on human kinin-forming enzymes in vitro. Tea is a highly consumed beverage in the world. Factor XII (FXII, Hageman factor)-independent- and -dependent activation of prekallikrein to kallikrein leads to the liberation of bradykinin (BK) from high-molecular-weight kininogen (HK). The excessive BK production causes vascular endothelial and nonvascular smooth muscle cell permeability, leading to angioedema. The prevalence of angiotensin-converting enzyme inhibitor (ACEI)-induced angioedema appears to be through BK. Both histamine and BK are potent inflammatory mediators. However, the treatments for histamine-mediated angioedema are unsuitable for BK-mediated angioedema. We hypothesized that long-term consumption of tea would reduce bradykinin-dependent processes within the systemic and pulmonary vasculature, independent of the anti-inflammatory actions of polyphenols. A purified fraction of the black tea water extract inhibited both kallikrein and activated FXII. The black tea water extracts inhibited factor XII-induced cell migration and inhibited the production of kallikrein on the endothelial cell line. We compared the inhibitory effects of the black tea water extract and twenty-three well-known anti-inflammatory medicinal herbs, in inhibiting both kallikrein and FXII. Surprisingly, arjunglucoside II specifically inhibited the activated factor XII (FXIIa), but not the kallikrein and the activated factor XI. Taken together, the black tea water extract exerts its anti-inflammatory effects, in part, by inhibiting kallikrein and activated FXII, which are part of the plasma kallikrein–kinin system (KKS), and by decreasing BK production. The inhibition of kallikrein and activated FXII represents a unique polyphenol-independent anti-inflammatory mechanism of action for the black tea.     

High-performance Liquid Chromatographic Analysis of Pioglitazone,Gliquidone,Rosuvastatin and Simvastatin in Formulations and Human Serum

Co‐administration of HMG‐CoA reductase with antidiabetic drugs is most common since antidiabetic drugs are mostly prescribed for long term therapy. In the present paper, we describe the simultaneous determination of antidiabetic (pioglitazone hydrochloride and gliquidone) in presence of statins (rosvastatin and simvastatin) in formulations and in human serum using RP‐HPLC technique. The serum samples were subjected to protein precipitation with acetonitrile prior to an HPLC analysis. At a flow rate of 1 mL·min⁻¹ isocratic elution was employed, using mobile phase consisting of methanol/water (90:10, V:V), pH 3.50 with phosphoric acid and absorbance was recorded at 235 nm. The assay was reproducible, linear (concentration range of 5–50 μg·mL⁻¹) and accurate. The LOD and LOQ values were 1.32, 0.28, 0.05 and 0.57 μg·mL⁻¹ and 4.39, 0.93, 0.16 and 1.90 μg·mL⁻¹ for pioglitazone hydrochloride, gliquidone, rosvastatin and simvastatin, respectively. There were no interfering peaks due to the excipients present in the pharmaceutical tablet and serum. Thus, the proposed method is simple and suitable for the analysis of active ingredient in tablet form and human serum.     

Stilbene derivatives from two species of Gnetaceae

Five new stilbene oligomers (gnemonols A, B and C, gnemonoside E and gnetal) were isolated together with 2b-hydroxyampelopsin F and gnetin E from Gnetum gnemon and G. gnemonoides. The structures of the compounds were elucidated on the basis of spectral evidence.     

Properties of single and multiple defect modes in one-dimensional photonic crystals containing left-handed metamaterials

Wave propagation is studied in structures consisting of alternate left- and right-handed layers.Bragg gap and zero-n gap appear in different frequency regions of the structure.The periodicity of the structure is broken by simply reversing the order of the layers in one half of the structure,resulting in defect modes located inside the zero-n gap and Bragg gap.These modes can be made very narrow by adding more layers in the structure.The defect mode located inside the zero-n gap is sensitive to the symmetry of the structure and insensitive to the angle of incidence of the incoming radiation.Multiple modes are also generated inside the gaps by repeating the structural pattern.Thus,a simple structure can be used for single and multiple modes that are important for different applications.     

Fabrication and characterization of nanocrystalline Al,Co:ZnO thin films by a sol–gel dip coating

The consequence of annealing on the micro-structural and electrochemical characteristics of Al doped CoZnO thin films deposited by sol–gel dip coating technique are studied. X-ray diffraction indicates that films have a hexagonal wurtzite structure oriented towards the (100). Optical properties of films are recorded by transmission curves utilising a UV–VIS spectrophotometer. The investigation of the optical transmission spectra indicates that the band gap of the films decrease from 3.99 eV to minimum 3.83 eV upon annealing. All films show room temperature ferromagnetism whose magnetization increases with annealing. Dip coated films possess polycrystalline nanosized grains with porous morphology.     

Understanding the interactions in acrylic copolymer/1‐butyl‐3‐methylimidazolium chloride from solution rheology

The effects of the type and content of comonomers on the rheological properties of acrylic copolymers in 1‐butyl‐3‐methylimidazolium chloride ([BMIM]Cl) were explored. According to the de Gennes scaling law for solution, comparison of intrinsic viscosity and scaling analysis of the exponent in the specific viscosity‐ and relaxation time‐concentration power law indicated that solution of both polyacrylonitrile (PAN) homo‐polymer and copolymer poly(acrylonitrile‐co‐methyl acrylate) (poly(AN‐co‐MA)) in [BMIM]Cl behave in the same manner as neutral polymer in a θ‐solvent. However, [BMIM]Cl acts as a more good solvent for poly(acrylonitrile‐co‐acrylamide) (poly(AN‐co‐AM)). The dissolution and unique rheological behavior of such solutions have been attributed to the interactions between copolymer chains and [BMIM]Cl. The interactions between nitrile group (?C≡N) and 1‐butyl‐3‐methylimidazolium cation ([BMIM]⁺) should interrupt and break the dipolar‐dipolar interactions of PAN resulting in the subsequent dissolution of the polymer in [BMIM]Cl. Such interactions between ?C≡N and [BMIM]⁺ ion are still dominated by the solvating ability of poly(AN‐co‐MA) in [BMIM]Cl, even though carbonyl group (C=O) in MA repeating unit could coordinate to cation of the ionic liquid. The salvation capacity of [BMIM]Cl for poly(AN‐co‐AM) can be evidently improved due to the extra hydrogen bond interactions between ?NH₂ group of AM and anion of [BMIM]Cl. Copyright © 2012 John Wiley & Sons, Ltd.     

Low temperature M?ssbauer and DC magnetization studies in nano-sized Ni substituted Co�CZn ferrites

Studies in the series of nano ferrites pertaining to the stoichiometry Ni_xCo_0.5???xZn_0.5Fe₂O₄, (0?? x ??0.5) show that contrary to the trend in bulk Co?CZn and Ni?CZn ferrites, the observed saturation magnetization of Ni?CZn ferrite (x = 0.5) is larger than Co?CZn ferrite (x = 0) and are due to finite size effects. This is evident from calculations which show that the magnetic particle sizes are 1.6 nm for Co?CZn ferrite and 2.4 nm for Ni?CZn whereas their average crystallite sizes are 5 to 3 nm respectively. Low temperature Mössbauer spectroscopic studies show that this can be attributed to an increase in an ordered core with the increase in Ni content which is reflected as a corresponding increase in the saturation magnetization.     

Orange Peel Derived C‐dots Decorated CuO Nanorods for the Selective Monitoring of Dopamine from Deboned Chicken

A novel electrode based on orange peel derived C‐dots decorated CuO nanorods (CR@C‐dot) modified lead pencil (LP) electrode has been fabricated for highly sensitive and selective monitoring of dopamine (DA). Prior to the functionalization with C‐dot, electrochemical efficacy of CR was evaluated and compared with CuO nano‐needles (CN) and nano‐spheres (CS). The morphology, surface area and composition of synthesized nanoparticles was confirmed through field emission scanning electron microscopy (FE‐SEM), N₂‐adsorption‐desorption isotherm, X‐ray diffraction (XRD), Raman spectroscopy and X‐ray photoelectron spectroscopy (XPS). Our results indicated that CR has high electrocatalytic activity compared to CN and CS by expositing greater fraction of catalytic active sites, large surface area and short diffusion pathways. The electrochemical efficacy of CR is further enhanced by decorating with orange peel derived C‐dots, which surprisingly lead to the integrations of surface‐active sites with current collectors with minimum resistance by acting as an electron transport mediator and providing more surface defects. The developed CR@C‐dot sensor enables highly sensitive and selective recognition of DA detection (0.0007 μM), over good linear range (5–2250 μM) with rapid response time. the developed CR@C‐dot sensor was successfully used to monitor the DA from deboned chicken, thus suggesting reliability of the developed electrode.