VOLUME 42, NO2, APR-2020

Structural, Topographical and Optoelectronic Properties of ZnIn2S4 Thin Films Deposited from Dual Source Using Aerosol Assisted Chemical Vapour Deposition (AACVD) Technique

The ZnIn2S4 (ZIS) thin films have been successfully developed from a homogeneous toluene solution of dithiocarbamate complexes of zinc and indium with formula [Zn(S2CNCy2)2(py)] (1) and [In(S2CNCy2)3].2py (2) via aerosol assisted chemical vapor deposition (AACVD) technique. Deposition experiments were carried out at 500oC in an inert atmosphere of argon gas on FTO substrate. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and Raman spectroscopy have been used for the determination of phase purity, surface topography of the uniformly distributed particles and oxidation states of the elements present in thin films. Further UV-visible spectrophotometry elucidates that the thin films absorbs in entire visible region and give estimated band gap energy of 2.37 eV. The photoelectrochemical (PEC) response in terms of linear scan voltammetry (LSV) provides a photocurrent density 2.27 mA.cm-2 at 0.7 V vs Ag/AgCl/3M KCl using 0.05 M sodium sulphide solution under AM 1.5 G illumination (100 mW.cm-2). The LSV results are further reinforced by electrochemical impedance spectroscopy (EIS) that gives charge transfer resistance (Rct) value of 5.7 x 104 Ω under dark conditions and reduces to 3.7 x 104 Ω under illumination.read more

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Umar Daraz, Tariq Mahmood Ansari, Shafique Ahmad Arain, Muhammad Adil Mansoor and Muhammad Mazhar

Characterization of Sol-gel Prepared Silica Supported NiO-CuO Composites

Silica (SiO2) supported nickel oxide-copper oxide (NiO-CuO) composites were synthesized through alkoxide route of sol-gel process using tetraethyl ortthosilicate (TEOS), nickel nitrate hexahydrate and copper nitrate trihydrate as precursors. A series of different compositions were prepared varying NiO:CuO molar ratios keeping all other process parameters constant. The gels thus obtained were calcined at a moderate temperature i.e. 500ºC for one hour. The crystal structure and thermal stability of metal oxide particles embedded in silica matrix were studied using X-ray diffraction technique (XRD) and differential scanning calorimetry (DSC-TGA) respectively. The purity of the composites was checked by Infrared spectroscopy (IR) whereas the composite formation was confirmed by scanning electron microscopy. The results revealed that crystals of NiO and CuO nanoparticles aggregated to form spheres of variable sizes were successfully embedded in the amorphous silica matrix composed of silica particles agglomerated to form clusters.read more

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Samreen Zahra, Dr. Narjis Naz, Dr. Muhammad Zia-ur-Rehman, Muhammad Irfan Asma Sheikh and Sania Izhar

Rapid and Sensitive Bioanalytical Method Development and Validation for Quantification of Metoprolol Using LC-MS/MS in Human Plasma

A novel, accurate, simple and selective LC-MS/MS method was developed and validated for the determination of metoprolol in human plasma. Due to structural resemblance Propranolol was selected as internal standard. Anti coagulant used was K2 EDTA. Metoprolol, used in the therapy and management of hypertension, myocardial infraction and other cardio vascular diseases. Liquid – liquid extraction technique with tert-butyl methyl ether was applied for the extraction of analyte from human plasma. Kromasil C18 column (5µ, 100 × 4.6 mm) with an isocratic mobile phase of 5mM Ammonium Formate pH 3.5 and Acetonitrile (15:85 % V/V) was used for the resolution. Sample ionization was done with Electrospray ionization technique in positive ion mode. Selectivity was enhanced by tandem mass spectrometric analysis via two multiple reaction monitoring (MRM) transitions, m/z 268.15→115.90 for metoprolol and 260.17→115.90 for Propranolol respectively. The linearity of the method was established over a concentration range of 1.505 – 538.254 ng/mL, in human plasma, with the precision and accuracy ranging from 4.67 to 7.41% and 90.66 to 98.15% respectively. The stability of the analyte was evaluated in plasma under different storage conditions.read more

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Beludari Mohammed Ishaq, Lingareddygari Siva Sanker Reddy, Gajula Mahaboob Basha, Munna Sreenivasulu, Challa Madhusudhana Chetty and Hindustan Abdul Ahad

Interaction of Nitroglycerin with Bovine Serum Albumin and the Influence of Metal Ions on the Binding

The effect of Cu2+, Ca2+, Mg2+and Zn2+ on the interaction between nitroglycerin and bovine serum albumin was investigated. The bimolecular quenching rate constant, the Stern-Volmer quenching constant, the binding constants and the number of binding sites were calculated in the absence and presence of Cu2+, Ca2+, Mg2+and Zn2+. The quenching constants of nitroglycerin to bovine serum albumin were increased in the presence of metal ions. Static quenching mechanism was also confirmed. The binding constants of nitroglycerin to bovine serum albumin were influenced by different metal ions. The enthalpy change, free energy chang, entropy change and the distance between the donor and the acceptor at different temperatures were calculated. The results indicated that energy transfer from bovine serum albumin to nitroglycerin occurs with high probability.read more

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Chengman Bao, Jialian Wang, Xuehong Tong, Chunli Zhang, Xinhui Tang

Potassium-Promoted Three-Dimensional Mesoporous Pt/MnO2 for Formaldehyde Elimination at Zero Degree

In this work, three-dimensional mesoporous MnO2, K/MnO2, Pt/MnO2 and K-Pt/MnO2 catalysts were prepared through hard-template method. The additional K/Pt had significantly improved the HCHO oxidation activity. The K-Pt/MnO2 catalyzed complete HCHO oxidation was achieved at 0℃ with space velocity (GHSV) at 50000 ml/(g·h). With the excellent catalytic performance, K-Pt/MnO2 exhibited a higher ratio of Oads(surface adsorbed oxygen)/Olatt(surface lattice oxygen) and Mn3+/Mn4+ ions than the other catalysts. Meanwhile, it was still stable after running a 70h reaction. Overall, the K-Pt/MnO2 was a promising material for HCHO elimination.read more

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Shengnan Guan, Wenzhi Li, Jianru Ma, Qingchuan Liu, Kun Chen and Qi Zhang

Novel Synthesis Method, Characterization and Bioactivities of a Copper(Ⅱ)-Hesperetin Complex Using Ion Exchange Column

A copper(Ⅱ)-hesperetin complex formulated as [Cu(L)2(H2O)2]·H2O ("L" represented the ligand hesperetin) was synthesized using a novel ion-exchanging resin column method, based on the integration of the separation of hesperetin on hesperetin-loaded resins and the reaction of hesperetin with Cu2+ using CuCl2 as an eluent and reacting reagent. The feasibility of this new method was testified firstly. Results indicated the D296 macroporous strong basic anion exchange resin could effectively adsorb hesperetin and the saturated adsorption capacity was 143.5 mg per mL resin. The favorable concentration of CuCl2 was 0.4 mol/L for the elution and the coordination process of hesperetin. The characterization of the copper(Ⅱ) complex was done by theoretical quantum chemical calculation, elemental and thermal analyses, UV-Vis absorption spectra, FTIR spectra and XRD analysis, results testified that the 4-carbonyl group and 5-hydroxyl group of hesperetin were involved in the coordination reaction. The comparison between hesperetin and its copper(Ⅱ) complex about their bioactivities like the inhibitory effect of α-amylase, antioxidant activities and solubility were evaluated. Results showed the bioactivities of the copper(Ⅱ) complex was better than that of hesperetin.read more

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Huan Wang, Boru Chen and Siming Zhu

Molecular Docking Studies on Gingerol Analogues toward Mushroom Tyrosinase

The gingerol presents the starting point of our work which aims to discover new inhibitors of the tyrosinase enzyme. Therefore, we have studied the activity of gingerol derivatives as inhibitors against mushroom tyrosinase based on the molecular docking. Molecular docking studies were performed on a series of gingerol analogues retrieved from Zinc database (with 70% as similarity threshold). The gingerol analogues were docked within the active site region of mushroom tyrosinase (PDB: 2Y9X) using Molegro Virtual Docker V.5.0. The results of molecular docking studies revealed that some analogues of gingerol have higher Moldock score (in terms of negative energy) than gingerol and the experimentally known inhibitors of tyrosinase, and showed favourable molecular interactions exhibiting common molecular interaction with Ala323, Met280 and Asn260 residues of tyrosinase. Furthermore, the top docked compounds used in this work do not violate the Lipinsky rule of five.read more

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Sabrina. Benouis, Fouad. Ferkous, Khairedine. Kraim, Ahmed. Allali, Youcef. Saihi

Antioxidant and Phenolic Characterization with HPLC of Various Extract of Verbascum glomeratum Linneus

Verbascum L. species have been used since ancient times in traditional medicine thanks to their bioactive compounds. In this study, we evaluated the antioxidant activity and phenolic contents of ethanolic and acetonic extract of Verbascum glomeratum that collected from Denizli, Turkey. The antioxidant activity were evaluated by using various methods (β-carotene/linoleic acid, ferric reducing power assays (FRAP), radical scavenging assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2'-azino-bis-3-ethyl benzthiazoline-6-sulphonic acid (ABTS), phoshomolibdenum methods) and total phenolic, flavonoid and tannin contents in the extracts were determined. Antioxidant activity was determined as β-carotene/linoleic acid (%58.5±0.021), DPPH (IC50: 1.220±0.025) and ABTS (IC50:1.552±0.021), ferric reducing antioxidant power (FRAP) (4.151±0.056 mgTE/g), phoshomolibdenum assay (8.218±0.015 mgAE/g) total phenolic, total flavonoid and tannin contents was found as (4.41±0.007 mgGAE/mL), (87.142±0.009 µQE/g), and (30.178±0.008 mgCEs/g) respectively, and then 14 different phenolic compounds in ethanol extracts was carried out by HPLC. Epicatechin (2742.09 µg/g) and 2,5dihidroksi (2544.96 µg/g) were the most abundant phenolic constituents in the extracts. According the results, the extract of V. glomeratum may be considered as a potential source of biological agents.read more

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Çiğdem Aydin, Akgul Rakhimzhanova, Özge Kilinçarslan and Ramazan Mammadov

Structure, Dielectric Properties and Impedance Spectroscopy of BaTi0.97(Zn,V,Ta)0.03O3 Ceramics

BaTi0.97Zn0.01V0.01Ta0.01O3¬ sample was prepared using the conventional mixed oxide sintering route. The samples were characterized using X-ray diffraction, Raman spectroscopy, Scanning Electron Microscopy and Impedance spectroscopy. Structure of the sample was analyzed using Rietveld analysis which showed the formation of tetragonal symmetry. Raman spectroscopy was also in agreement with the XRD results, further indicating the ferroelectric signature in the sample. Electrical microstructure analyzed by impedance spectroscopy analysis revealed two electroactive regions in the sample, belonging to the grain boundary and bulk. An extrinsic conduction mechanism was observed across the sample. Dielectric properties as a function of temperature demonstrated phase transition (TC) at ~ 94 °C, with relative permittivity ~ 3280 at TC. Antiferroelectric-like double hysteresis loops were observed in P-E analysis. The energy storage density was calculated to be 0.26 J/cm3 at an electric field of 50 kV/cm, indicating that BaTi0.97Zn0.01V0.01Ta0.01O3¬ ceramics can be potentially useful base materials for high density energy storage capacitors.read more

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Raz Muhammad, Sajid Ali, Yaseen Iqbal, Amir Khesro and Muhammad Uzair

Synthesis, Characterization and Antioxidant Activity of Nickel(II) Schiff Base Complexes Derived from 4-(Dimethylamino)benzaldehyde

Nickel(II) complexes of the following Schiff base ligands derived from 4-(dimethylamino)benzaldehyde were synthesised: (Z)-1-(4-(dimethylamino)benzylideneamino)-propan-1-ol through condensation with 1-amino-propan-1-ol, (N1E,N2E)-N1,N2-bis(4-dimethylamino)benzylidene)benzene-1,2-diamine through condensation with benzene-1,2-diamine and 2-((4-dimethylamino)benzylidene)amino)phenol through condensation with 2-aminophenol. The synthesised Schiff bases and the resultant Ni(II) complexes were all isolated as crystals and characterized by melting point, elemental analysis, infrared spectroscopy, NMR spectroscopy, mass spectrometry and by conductance measurements. Antioxidant activity of the Ni(II) complexes was tested by assay with the free radical compound 2,2-diphenyl-1-picrylhydrazyl (DPPH).read more

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Nighat Nawaz, Irshad Ahmad, Nizam M. Darwesh, Amjad Wahab, Sadeeq ur Rahman, Abdul Sajid, Farhan A. Khan, Sher B. Khan, Simon G. Patching and 1Kamal Uddin