Etching and dielectric studies on L‐lysine monohydrochloride dihydrate single crystal

The nonlinear optical single crystals of L‐Lysine monohydrochloride dihydrate (L‐LMHCl) have been grown and examined by High‐resolution X‐ray diffraction and etching studies for their perfection. The vibrational frequencies have been identified by the micro‐Raman studies and the dielectric behaviour has been studied and the results are presented in detail. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Weak π-rings

In this paper we establish some characterizations for weak π-rings.     

Piperidone derivative from Dalbergia sympathetica

An alcoholic extract of Dalbergia sympathetica, on column chromatography, yielded a compound which analyzed for C(6)H(11)NO(3) (M(+) 145). The IR spectrum of the compound showed the presence of carbonyl and hydroxyl groups. PMR, (13)C and DEPT NMR spectral studies of the compound showed the presence of one N-methyl, two methine and two methylene groups. A quaternary carbon signal at delta 172.88 ppm was assigned to C-2 carbonyl of the compound. From all the above observations and also from the HMQC 2D NMR spectrum, the compound was identified as 3, 6-dihydroxy-N-methyl-2-piperidone. This is the first report of the natural occurrence of this compound from plant sources.     

Design and fabrication of an ultraviolet photoelectron spectrometer for the study of free molecules

An ultraviolet photoelectron spectrometer for the study of free atoms and molecules has been designed and fabricated with indigeneous components. The spectrometer consists of a 100 mA HeI discharge lamp, 180° hemispherical electron energy analyser (127 mm mean dia) and electron multiplier ratemeter electron detection systems. The resolution of the spectrometer is 90 meV/and the intensity of N₂ (5σ) band is 10⁵ c/sec. The sample inlet and the collision chamber can be heated to 500 K so that solids of low vapour pressure can be studied. Typical spectra of molecules recorded with the instrument are shown. Contribution No. 373 from the Solid State and Structural Chemistry Unit.     

Influence of molecular weight and degree of segregation on local segmental dynamics of ordered block copolymers

Experiments in the context of block copolymer electrolyte materials have observed intriguing dependence of the ionic conductivities upon the polymer molecular weight and the degree of segregation between the blocks. Such results have been partly rationalized by invoking the spatial extent of dynamical inhomogeneities that manifest in ordered phases of block copolymers comprised of a rubbery and a glassy block. Motivated by such observations, we use molecular dynamics simulations to study the extent of spatial inhomogeneities in segmental dynamics of lamellar diblock copolymer systems where the blocks possess different mobilities. We probed the local average relaxation times and the dynamical heterogeneities as a function of distance from the interface. Our results suggest that the relaxation times of rubbery segments are strongly influenced by both the spatial proximity to the interface and the relative mobility of the glassy segments. Scaling of our results indicate that the interfacial width of the ordered phases serves as the length scale underlying the spatial inhomogeneities in segmental dynamics of the fast monomers. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 859–864     

Isolation and characterisation of bioactive isoflavonoids from the roots of Dalbergia horrida

The roots of Dalbergia horrida yielded two new isoflavanones, Dalhorridin (I) - 5,5'-dihydroxy-3',4'-methylenedioxy-5'-prenyl-6',6'-dimethyl-dihydropyrano(2',3' : 7,8)-isoflavanone and Dalhorridinin (II) - 5,7,5'-trihydroxy-3',4'-methylenedioxy-8-[5-methyl-2-(2-hydroxyisopropyl)-1,4-hexadienyl]isoflavanone along with two known isoflavones, Dalspinin and Dalspinosin. Preliminary biological screening of the enriched extract revealed that it showed analgesic, anti-inflammatory, CNS depressant and mild anti-bacterial properties.     

A note on the special unitary group of a division algebra

If is a division algebra with its center a number field and with an involution of the second kind, it is unknown if the group , is trivial. We show that, by contrast, if is a function field in one variable over a number field, and if is an algebra with center and with an involution of the second kind, the group can be infinite in general. We give an infinite class of examples.

     

A physicochemical model for analyzing DNA sequences

In search of an ab initio model to characterize DNA sequences as genes and nongenes, we examined some physicochemical properties of each trinucleotide (codon), which could accomplish this task. We constructed three-dimensional vectors for each double-helical trinucleotide sequence considering hydrogen-bonding energy, stacking energy, and a third parameter, which we provisionally identified with DNA-protein interactions. As this three-dimensional vector moves along any genome, the net orientation of the resultant vector should differ significantly for gene and nongene regions to make a distinction feasible, if the underlying model has some merits. An analysis of 331 prokaryotic genomes comprising a total of 294 786 experimentally verified genes (nonoverlapping) and an equal number of nongenes presents a proof of concept of the model without the need for further parametrization. Also, initial analyses on Saccharomyces cerevisiae and Arabidopsis thaliana suggest that the methodology is extendable to eukaryotes. The physicochemical model (ChemGenome1.0) introduced has the potential to be developed into a gene-finding algorithm and, more pressingly, could be employed for an independent assessment of the annotation of DNA sequences.     

Characterization of melt grown phthalic anhydride single crystal

The bulk organic single crystal of phthalic anhydride (PA) was grown by vertical Bridgman technique. The structural perfection of the grown crystal was analysed by high resolution X‐ray diffraction (Multicrystal X‐ray diffractometry) studies. The thermal and mechanical properties have been studied. The second harmonic generation relative efficiency of Phthalic anhydride crystal is compared with KDP crystal. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)