A quantitative study of diffracted X-ray intensities from type I natural diamond crystals by high resolution X-ray diffractometry and comparison with nearly perfect silicon single crystals

Results of accurate measurements of peak and integrated intensities of , 111 and 333 reflections of natural diamonds of type I and nearly perfect silicon single crystals are reported. Highly monochromated and collimated MoK _{α 1} exploring beam was used. A quadrupole crystal X-ray diffractometer was employed in (+, −, +) and (+, −, +, −) settings. (111) platelets of diamond and silicon crystals with thicknesses of about 1 mm were selected. High resolution diffraction curves, stationary and traverse topographs were recorded. Diffraction curve half widths of diamond and silicon crystals were in the range: 45–200 arc sec and a few arc sec respectively. The experimental values of integrated intensitiesρ for diamond crystals were found to lie between the theoretical values for ideally perfect and ideally imperfect crystals. Experimental values ofρ for silicon were closer to the “perfect crystal” values. This is consistent with the results of diffractometric and topographic evaluation. The peak intensities of all reflections were higher for diamond crystals in comparison to the silicon crystals. The ratioI _C/I _Si lies in the range 1.3 (111 reflection) to 10.5 and (333) reflections. This is anomalous and cannot be accounted for by considering the degree of perfection, structure factor and difference in absorption coefficient.     

Normal and abnormal heme biosynthesis. 3.(1)Synthesis and metabolism of tripropionate analogues of coproporphyrinogen-III: novel probes for the active site of coproporphyrinogen oxidase

Coproporphyrinogen oxidase (copro'gen oxidase) catalyses the oxidative decarboxylation of two propionate side chains on coproporphyrinogen-III to produce protoporphyrinogen-IX. This process is very poorly understood at a molecular level, and copro'gen oxidase remains one of the least well-characterized enzymes in the heme biosynthetic pathway. To provide a rigorous test for a proposed model for substrate recognition and binding by this enzyme, two tripropionate analogues of copro'gen-III were prepared where an ethyl group replaced one of the usual propionate residues on positions 13 or 17. Although the required substrate probes are porphyrinogens (hexahydroporphyrins), the corresponding porphyrin methyl esters were initially synthesized via tripyrrene and a,c-biladiene intermediates. These were hydrolyzed and reduced with 3% sodium-amalgam to give the unstable porphyrinogens needed for the biochemical investigations. The modified structure with a 13-ethyl moiety was metabolized by avian preparations of copro'gen oxidase to give a monovinylic product, but the isomeric 17-ethylporphyrinogen afforded a divinylic product, albeit with poorer overall conversion. These results strongly support the proposed model for substrate binding at the active site of copro'gen oxidase.     

A single reagent thyroxine radioimmunoassay

An homogenous radioimmunoassay of thyroxine using labelled antigen antibody complex as a single reagent is described. Variation of dose response curve slope with assay incubation time has been studied at two different antisera concentrations. The dissociation constant of the complex was found to be 3.5·10⁻⁴ s⁻¹. The assay involves only three pipettings and requires 45 minutes incubation at 37 °C and 10 μl of serum. Though the assay is essentially a nonequilibrium type, apparent increase in sample values, due to the drift of dose response curve for 45 minutes delay was less than 7.5%. Within and between assay variations were both less than 5% c. v. Assay has been validated by recovery experiments. Analysis of 40 serum samples by the proposed method and by an equilibrium assay gave similar values; r=0.957, Y=0.955X+0.478.     

Synthesis,spectral, DFT,and antimicrobial studies of tin(II) and lead(II) complexes with semicarbazone and thiosemicarbazones derived from (2-hydroxyphenyl)(pyrrolidin-1-yl)methanone

A new series of metal complexes [M(L)₂] (where M = Sn(II), Pb(II), and HL = semicarbazone, thiosemicarbazone or phenylthiosemicarbazone) have been prepared and characterized by elemental analysis, conductance measurements, molecular weight determinations, UV–visible, infrared, and nuclear magnetic resonance (¹H-, ¹³C-, and ¹¹⁹Sn-NMR) spectral studies. Elemental analysis of the metal complexes suggested 1 : 2 (metal–ligand) stoichiometry. Infrared spectra of the complexes agree with coordination to the metal through the nitrogen of the azomethine (>C=N?) and the oxygen/sulfur of the ketonic/thiolic group. Electronic spectra suggest a distorted tetrahedral geometry for all Schiff base complexes. The bond lengths, bond angles, highest occupied molecular orbital, lowest unoccupied molecular orbital, Mulliken atomic charges, and the lowest energy model structure of the complexes have been determined with DFT calculations. Representative Schiff base and its metal chelates have been screened for their in vitro antibacterial activity against four bacteria, Gram-positive (Bacillus cereus, Staphylococcus aureus) and Gram-negative (Escherichia coli, Klebsiella pneumoniae) and four strains of fungus (Penicillium chrysogenum, Aspergillus niger, Rhizopus nigricans, and Alternaria alternata). The metal chelates possess higher antimicrobial activity than the free ligands.     

Peroxidative catalytic oxidation of alcohols catalyzed by heterobinuclear vanadium(V) complexes using H2O2 as terminal oxidizing agents

Here we report the catalytic oxidation of benzylic alcohol, hetero‐aryl alcohols and propargylic alcohols to their corresponding carbonyl compound using heterobimetallic sodium‐dioxidovanadium(V) complexes. The present catalytic oxidation studies proceed at 70 °C using H₂O₂ as terminal oxidant. During the whole process, the complexes react with hydrogen peroxide to form peroxo‐vanadium(V) species. The present study shows the heterogeneity of pre‐catalyst which could be easily recovered and moreover isolation of product is very simple.     

Utilising oleogel as a frying medium for deep fried Indian traditional product (Mathri) to reduce oil uptake

The purpose of this research was to use and analyze the influence of oleogel as a frying medium for developing low fat fried Indian traditional snack (Mathri). As consumer demand for fried foods grows, so does consumer concern about their health, as they are responsible for a variety of health disorders. Carnauba wax and soybean oil were used to produce oleogel in three different concentrations (5, 10 and 15%) which were further examined and used as frying medium. The oleogel effect on the quality attributes of snack were also investigated and compared with the soybean refined oil in this study. It was observed that Mathri fried in oleogel had better moisture retention, color, texture and a lower oil uptake than the Mathri fried in soybean oil. Moisture content in CRW samples ranged from 4 to 5%, but rose to 8.98% in the case of oil samples. Breaking strength of mathri fried in oil was 3382.1 ?g, which was more than the breaking strength of mathri fried in oleogel, which were 1974.8 ?g (5% CRW) and 1092.7 ?g (10% CRW) and 3168.1 ?g (15% CRW). Oleogel fried mathri absorbed 27.7%, 22% and 19.3% less oil than conventionally fried ones. The study shows that mathri with reduced fat and calorie content can be developed to suit the demand among health-conscious consumers for low fatty foods.