o-Nitrobenzoyl group as a new amino protecting group for peptide synthesis and the synthesis of some anthranilyl peptides

N (o-nitrobenzoyl)amino acids can be coupled with other amino acids using DCC and the resulting product on hydrogenation gives peptides, containing the anthranilyl group as —NH₂ end group. N (anthranilyl)amino acids or peptides can also be obtained by reaction of isatoic anhydride on amino acids or peptides. The anthranilyl end group is easily cleaved by metal (Cu⁺²) catalysed hydrolysis to give α-amino acid peptides and the insoluble copper(II) anthranilate.     

Effect of corona discharge on cadmium sulphide and lead sulphide films

This paper describes the effect of corona discharge on cadmium sulphide (CdS) and lead sulphide (PbS) films prepared using the chemical route. The property of films before and after exposure to corona has been described in detail. The electronic properties of the CdS and PbS films have been studied by current-voltage (I-V), capacitance-voltage (C-V) measurements. The structural properties and surface morphology were studied by using X-ray diffraction and scanning electron microscopy before and after exposing to Corona discharge. The films displayed the change in surface morphology after exposure to the corona discharge. It has been found that the films showed an increase in resistivity after exposure. This change in property has been attributed to modification in surface states. Time-dependent recovery indicated that room temperature annealing is sufficient to regain the normal resistivity of the films. The experiment was carried with the aim of studying the effect of the interaction of corona discharge on the semiconductor films and its subsequent effects.     

The Roles of Composition and Mesostructure of Cobalt-Based Spinel Catalysts in Oxygen Evolution Reactions

By using the crystalline precursor decomposition approach and direct co-precipitation the composition and mesostructure of cobalt-based spinels can be controlled. A systematic substitution of cobalt with redox-active iron and redox-inactive magnesium and aluminum in a cobalt spinel with anisotropic particle morphology with a preferred 111 surface termination is presented, resulting in a substitution series including Co₃O₄, MgCo₂O₄, Co₂FeO₄, Co₂AlO₄ and CoFe₂O₄. The role of redox pairs in the spinels is investigated in chemical water oxidation by using ceric ammonium nitrate (CAN test), electrochemical oxygen evolution reaction (OER) and H₂O₂ decomposition. Studying the effect of dominant surface termination, isotropic Co₃O₄ and CoFe₂O₄ catalysts with more or less spherical particles are compared to their anisotropic analogues. For CAN-test and OER, Co³⁺ plays the major role for high activity. In H₂O₂ decomposition, Co²⁺ reveals itself to be of major importance. Redox active cations in the structure enhance the catalytic activity in all reactions. A benefit of a predominant 111 surface termination depends on the cobalt oxidation state in the as-prepared catalysts and the investigated reaction.     

Bergenia Genus: Traditional Uses,Phytochemistry and Pharmacology

Bergenia (Saxifragaceae) genus is native to central Asia and encompasses 32 known species. Among these, nine are of pharmacological relevance. In the Indian system of traditional medicine (Ayurveda), “Pashanabheda” (stone breaker) is an elite drug formulation obtained from the rhizomes of B. ligulata. Bergenia species also possess several other biological activities like diuretic, antidiabetic, antitussive, insecticidal, anti-inflammatory, antipyretic, anti-bradykinin, antiviral, antibacterial, antimalarial, hepatoprotective, antiulcer, anticancer, antioxidant, antiobesity, and adaptogenic. This review provides explicit information on the traditional uses, phytochemistry, and pharmacological significance of the genus Bergenia. The extant literature concerned was systematically collected from various databases, weblinks, blogs, books, and theses to select 174 references for detailed analysis. To date, 152 chemical constituents have been identified and characterized from the genus Bergenia that belong to the chemical classes of polyphenols, phenolic-glycosides, lactones, quinones, sterols, tannins, terpenes, and others. B. crassifolia alone possesses 104 bioactive compounds. Meticulous pharmacological and phytochemical studies on Bergenia species and its conservation could yield more reliable compounds and products of pharmacological significance for better healthcare.     

Inclusive ∑±(1385) production inK − p interactions at 110 GeV/c

Results are presented on inclusive production of ∑⁺(1385) and ∑^?(1385) inK ^? p interactions at 110 GeV/c. The inclusive and topological cross sections have been estimated and compared with published results at lower energies. The inclusive cross section of ∑⁺(1385) seems to decrease with c.m. energy, while that of the ∑^?(1385) is nearly constant. The mean charged multiplicity associate to Σ(1385) increases with c.m. energy. The ∑⁺(1385) is produced both in the target fragmentation region and in the central region where ∑^?(1385) is predominantly produced in the central region. Approximately 16% of the Λ's stem from the decay of ∑^±(1385) and the kinematic distributions of these Λ's are not very different from the inclusive Λ's.     

On a Kolmogorov-Smirnov type aligned test in linear regression

For testing the hypothesis that the two distributions differ only in regression lines, parallel or not, asymptotically distribution free test of Kolmogorov-Smirnov type based on certain aligned observations are proposed.     

A new synthesis of aldehydes from acids via reduction of N-acyl saccharins using sodium dihydro bis-(2-methoxy-ethoxy) aluminate

Synthesis of certain aldehydes from the carboxylic acids has been carried by reduction of the corresponding N-acyl saccharins using SDA. The N-acyl saccharins are easily prepared by reaction of an acid with γ-saccharin chloride, which can be used for the next step of reduction without isolation and purification. This provides a convenient and one step synthesis of aldehydes by combining the two reactions, viz., preparation of the N-acyl compound and its reduction. The method has been successfully applied for the reduction of aliphatic, alicyclic, aromatic, and a α,β-unsaturated acids to the corresponding aldehydes and the yields obtained are quite satisfactory.     

Asymptotic normality of H-L estimators based on dependent data

LetX ₁,X ₂, ... be a strictly stationary φ-mixing sequence of r.v.'s with a common continuous cdfF. Let θ be a location parameter ofF. We prove the asymptotic normality of a class of Hodges-Lehmann estimators of θ under various regularity conditions on the mixing number φ and the underlyingF. We also establish the asymptotic linearity of signed rank statistics in the parameter θ. Our results also enable us to study the effect of φ-dependence on the asymptotic power of signed rank tests for testingH ₀: θ=0 againstH _n :θ=θ ₀ n ^?1/2,θ ₀≠0. Finally these results are shown to remain valid for strongly mixing processes {X _i } also.     

The chemical etching of fission fragment tracks in natural fluorite

An experimental study of the mechanism for chemical etching of fission fragment tracks in the natural mineral fluorite is described. A systematic search showed that a 3:1 mixture by volume of sulphuric to hydrochloric acids was a most appropriate etchant. Experiments directed at determining the etching efficiency as a function of solvent temperature are also discussed. The preferential track etch ratioVt/Vg, the track length and the track density all depend upon the time and temperature of annealing.

It is variations of the fission track density in fluorite, with etching time and annealing temperature, which make possible an overall geophysical interpretation of annealing data for the mineral in terms of the paleoisotherm of its intrinsic fission track clock.

An interactive image analysis system INTIMAN, assembled for the swift and automatic readout of fission fragment track measurements, in both crystalline and non-crystalline materials, is described. Normal procedures for measuring and analyzing tracks are outlined.     

110°C thermoluminescence glow peak of quartz — A brief review

The 110°C glow peak of quartz, though unstable at room temperature, has worked wonderfully in archaeology and retrospective dosimetry due to its pre-dose sensitization property. Various aspects of the peak, like its nature, defect centres involved, the impact of different stimuli and its application have been extensively studied. The main aims of this review are to (i) summarize briefly the work carried out on the various facets of this TL glow peak during the last four decades and (ii) identify the areas which need further attention in order to have a better understanding of the luminescence characteristics of this TL peak.