A simple theoretical extension to the analysis of photothermal deflection signal for low thermal diffusivity evaluation

A modified amplitude method to analyze the photothermal probe beam deflection signal for the determination of low thermal diffusivity values of materials is proposed. This simple theoretical model, which is an extension of the amplitude method proposed by Quelin et al., takes into account the dependence of the photothermal signal on the height of the probe beam above the sample surface which affects mirage measurements when the thermal diffusivity of the coupling medium is greater than that of the sample. The present work is similar to the modification to the phase method proposed by Bertolotti et al. for determination of low thermal diffusivity. The method can be applied irrespective of whether the sample is optically transparent or optically opaque and is independent of thickness.     

A Multicomponent,Catalyst‐free,One‐Pot Synthesis of Functionalized 1,4‐Dihydroquinolines and Their Antimicrobial Studies

An atom‐efficient, catalyst‐free, and environmentally friendly approach towards the synthesis of substituted 1,4‐dihydroquinolines ( 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j ) through a one‐pot multicomponent reaction involving resorcinol, aromatic aldehyde, acetoacetanilide, and ammonium acetate has been developed. The reactions were carried out under both conventional and microwave irradiation conditions. In general, improvement in rate and yield were observed when reactions were carried out under microwave irradiation compared with classical conditions. Most of the new compounds possessed moderate to significant antibacterial and antifungal activities.     

Synthesis,characterization, and applications with the manifestation of antifungal activity and seed germination properties of nickel doped zinc oxide nano platform by biochemical contrivance

In the recent era, nanotechnology, a rapidly emerging field, has been explored as the most studied field worldwide. The goal of this study is to use neem leaves extract as an effective ‘reducing agent’ and ‘stabilizing agent’ in the green synthesis of bio-medically important Zn_1-XNi_XO (X = 0.00, 0.04, 0.08, 0.12) nanoparticles. The molar concentrations of nickel nitrate and zinc nitrate are varied to produce nickel-doped ZnO nanoparticles. Color change is the first indicator of nanoparticle formation during this biosynthesis. The hexagonal wurtzite structure with good crystallinity is confirmed by X-ray diffraction. FTIR analysis reveals the fact that the Zn–O stretching vibration shifts with the introduction of impurities into the ZnO matrix. UV–Vis spectra show the typical surface plasma resonance around 370 nm and the hydrodynamic diameter is larger than the size calculated from the XRD value, according to DLS. The main finding of this study is that Ni_0.12Zn_0.88O has a strong antifungal activity against and a significant growth rate after treating wheat seeds with biologically synthesized Ni_0.12Zn_0.88O nanoparticles.     

Reduction of 2′-Hydroxy Chalcones Under Phase Transfer Catalysis—A new Method for the Synthesis of Flavan-4-OLS

Reduction of 2′-hydroxy chalcones under phase transfer catalysis conditions is discussed. The products are identified as 2,4-cis-fLavan-4-OLS.     

The melosatins—a novel class of alkaloids from melochia tomentosa1

Details of the isolation of malosatin A, B, and C and the synthesis of melosatin A are presented. Melosatin C has been characterized as 7-methoxy-4-(5-phenylpentyl)isatin. Several Me and OMe substituted isatins are synthesized as models and UV and mass spectra of the series are discussed.     

Simultaneous determination of pseudoephedrine hydrochloride and diphenhydramine hydrochloride in cough syrup by gas chromatography (GC)

A simple, rapid and precise gas chromatographic method has been developed for the simultaneous determination of pseudoephedrine hydrochloride and diphenhydramine hydrochloride in cough syrup, using a SS column of 10% OV 1 on chromosorb W-HP (80-100 mesh) and nitrogen as a carrier gas at a flow rate of 30 ml min(-1). The oven temperature was programmed at 135 degrees C for 1 min, with a rise of 10 degrees C min(-1) up to 250 degrees C (held for 5 min). The injector and detector port temperatures were maintained at 280 degrees C. Detection was carried out using Flame ionization detector. Guaphenesin was used as an internal standard. Results of assay and recovery studies were statistically evaluated for its accuracy and precision.     

Determination of cobalt by substoichiometric thermal neutron activation analysis

A selective method has been developed for the determination of traces of cobalt in different matrices by the sensitive technique of thermal neutron activation analysis employing radiochemical separation and substoichiometric extraction of Co/II/ with iso-nitrosobenzoylacetone into chloroform.     

Contributions of a long side chain to the binding affinity of an anthracene derivative to DNA

Systematic studies on the DNA binding of a new anthracene derivative, carrying a 1,8-octyldiamine side chain, were carried out. Calorimetric, spectroscopic, and helix melting studies show that the side chain, consisting of eight methylene groups, enhances the binding constant by a factor of approximately 35 when compared to the binding of a probe lacking the long side chain. Furthermore, the enthalpy of binding of the long-chain derivative to calf thymus DNA (Delta H = 4.1 +/- 0.1 kcal/mol) is far greater than the sum of the enthalpy changes associated with the binding of the probe lacking the long side chain, and the enthalpy for the binding of 1,8-octyldiamine.2HCl. Strong synergistic effects, therefore, are seen with the long-chain derivative. Spectroscopic data indicate bathochromism, strong hypochromism, and quenching of anthryl fluorescence when the above ligand binds to calf thymus DNA. Fluorescence energy transfer studies and circular dichroism data strongly suggest intercalation of the anthryl ring system. The binding stabilizes the double helix, and the helix melting temperature is increased from 78 degrees C to >90 degrees C. The binding to DNA is reversible, depended on the ionic strength, and the major binding mode was suppressed at high ionic strengths and a new mode begins to dominate binding. Substitution of the anthracene ring with 1,8-octyldiamine chain provided a simple method to enhance the binding constant by nearly a factor of 35.