Low temperature studies of grinding effect on the photo and electroluminescence of ZnO electroluminophores

Grinding effect on the photo and electroluminescence of ZnO electroluminophores has been investigated at liquid nitrogen temperature. Changes caused in integral intensity and spectra are in favour of our earlier proposed model.The authors are thankful to Dr. R. K. Thakur for his encouragement and to the University Grants Commision for awarding a Teacher Fellowship to one of them (RPA).     

Thin-Layer Chromatographic Enantioseparation of (RS)-Etodolac Using Indirect Approach

JPC – Journal of Planar Chromatography – Modern TLC - Enantioseparation of (RS)-etodolac was achieved by an indirect approach. Extraction of the drug (RS)-etodolac (Etd) was done from...     

Effect of Salicylic Acid on the Activity of PAL and PHB Geranyltransferase and Shikonin Derivatives Production in Cell Suspension Cultures of Arnebia euchroma (Royle) Johnst—a Medicinally Important Plant Species

Cell suspension cultures of Arnebia euchroma were established from the friable callus on liquid Murashige and Skoog medium supplemented with 6-benzylaminopurine (10.0 μM) and indole-3-butyric acid (5.0 μM). Salicylic acid was used to study its effect on the enzymes which participate in shikonin biosynthesis with respect to metabolite (shikonin) content in the cell suspension culture of A. euchroma. In our study, phenylalanine ammonia lyase and PHB geranyltransferase were selected from the entire biosynthetic pathway. Results showed that phenylalanine ammonia lyase is responsible for growth and PHB geranyltransferase for metabolite production. Salicylic acid exhibited an inverse relationship with the metabolite content (shikonin); salicylic acid (100 μM) completely inhibited shikonin biosynthesis. The results presented in the current study can be successfully employed for the metabolic engineering of its biosynthetic pathway for the enhancement of shikonin, which will not only help in meeting its industrial demand but also lead to the conservation of species in its natural habitat.     

Nano-formulation of 4-Hydroxy-3-methoxybenzohydrazide: Preparation,characterization and studies of antihyperglycemic and antioxidant activities as evaluated through amelioration of pancreatic Dysfunction in experimental animals

In the present work, nanoparticles of previously synthesized 3a derivatives of vanillic acid were synthesized by the nanoprecipitation method. Nanoparticles were further characterized by UV–vis spectroscopy, FTIR spectroscopy, SEM analysis, XRD and zeta sizer. Diabetes was instigated in Wistar albino rats by intraperitoneal (I.P.) administration of Streptozotocin (60 ?mg/kg body weight). Vanillic acid (100 ?mg/kg), 3a (100 ?mg/kg) and 3aNPs (50 ?mg/kg) body weight were given orally for a period of 21 days. Blood glucose level and biochemical parameters such as cholesterol, triglycerides, LDL, HDL, VLDL and antioxidant parameters were assessed by using diagnostic kits. SEM analysis and PDI of 3aNPs was found to be 0.2 which indicate monodisperse distribution. Significant decline in blood glucose level (p ?< ?0.001) was observed in antidiabetic studies along with the lipid lowering and antioxidant effect in dose-dependent manner. The noted results of the study showed that nanoparticles were found to be effective in treating diabetes.     

(RS)‐Propranolol: enantioseparation by HPLC using newly synthesized (S)‐levofloxacin‐based reagent,absolute configuration of diastereomers and recovery of native enantiomers by detagging

Diastereomers of (RS)‐propranolol were synthesized using (S)‐levofloxacin‐based new chiral derivatizing reagents (CDRs). Levofloxacin was chosen as the pure (S)‐enantiomer for its high molar absorptivity (ε_o ～ 24000) and availability at a low price. Its ‐COOH group had N‐hydroxysuccinimide and N‐hydroxybenzotriazole, which acted as good leaving groups during nucleophilic substitution by the amino group of the racemic (RS)‐propranolol; the CDRs were characterized by UV, IR, ¹H‐NMR, high resolution mass spectrometry (HRMS) and carbon, hydrogen, nitrogen, and sulphur fundamental elemental components analyser (CHNS). Diastereomers were separated quantitatively using open column chromatography; absolute configuration of the diastereomers was established and the reagent moiety was detagged under microwave‐assisted acidic conditions. (S)‐ and (R)‐propranolol as pure enantiomers and (S)‐levofloxacin were separated, isolated and characterized. Optimized lowest‐energy structures of the diastereomers were developed using Gaussian 09 Rev. A.02 program and hybrid density functional B3LYP with 6‐31G* basis set (based on density functional theory) for explanation of elution order and configuration. In addition, RP HPLC conditions for separation of diastereomers were optimized with respect to pH, concentration of buffer, flow rate of mobile phase and nature of organic modifier. HPLC separation method was validated as per International Conference on Harmonization guidelines. With the systematic application of various analytical techniques, absolute configuration of the diastereomers (and the native enantiomers) of (RS)‐propranolol was established. Copyright © 2016 John Wiley & Sons, Ltd.     

Resolution of enantiomers of DL-amino acids on silica gel plates impregnated with optically pure (-)-quinine.

TLC resolution of enantiomers from racemic amino acids was achieved on silica gel plates impregnated with optically pure (-)-quinine. The successful solvent systems were butanol-chloroform-acetic acid (3:7:5, v/v) for DL-methionine; 6:8:4, v/v for alanine; 10:1:4; v/v for threonine; and ethyl acetate-carbon tetrachloride-propionic acid (10.5:6.5:3.5, v/v) for valine. Minimum detection limits were found to be different for each of the amino acid, ranging between 0.9 and 3.7 microg. The effects of concentration of impregnating reagent, temperature and pH on resolution of enantiomers have been studied in details.     

Electroluminescence studies of chemically deposited (Zn‐Cd)S:Cu,F films

Electroluminescence (EL) emission has been observed under AC field excitation in chemically deposited (dipping technique) films of (Zn‐Cd)S:Cu,F using substrates of conducting glass plates. Results of XRD, SEM, absorption spectra, transmission spectra, EL emission spectra, voltage, frequency and temperature dependence and brightness waves of EL brightness are presented and discussed. SEM studies show better growth condition in presence of F. X‐ray diffraction studies show diffraction lines due to CdS and ZnS. Both the studies represent average particle sizes of the order of 1Å. Absorption studies show change in band gap due to increasing concentration of ZnS. The observed EL emission (blue‐green region) may be due to Cu, F combination. Results of transmission spectra give band gap similar to those given by absorption spectra. From voltage dependence of EL brightness acceleration‐collision mechanism is found to be effective. Frequency dependence of EL brightness shows first an increase in brightness in the lower frequency range followed by saturation at higher frequencies. Temperature dependence of EL emission shows a maximum at 40°C. Brightness waves consist of primary and secondary waves, which depend on voltage and frequency of excitation & the ambient temperature. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Microwave Assisted,Highly Efficient Solid state N- and S-Alkylation

Secondary amines and thiophenols were alkylated with alkyl and benzyl halides rapidly on alumina supported potassium carbonate under solvent-free conditions using microwaves. Equimolar amounts of the secondary amine/thiophenol and alkyl halide were used. The procedure neither required any strong base nor a PTC. Aniline was also monobenzylated with benzylchloride. Separation of the products from the reactants was very simple by using a nonpolar solvent for desorption.