Structural assignment of monothiocarbonohydrazones by 1H NMR spectroscopy

Analysis of the 1H NMR spectra of several monothiocarbonohydrazones, some of them synthesized for the first time, shows that they exist as two structural isomers. Whereas, in general, the derivatives of aromatic aldehydes conform to a linear structure, the aliphatic carbonyl derivatives conform to heterocyclic or linear structures, depending on the size of the substituent groups. This dual behaviour is explained in terms of extended conjugation and steric hindrance.

Thermal decomposition of methylammonium perchlorate

The thermal decomposition of methylammonium perchlorate (MAP) has been studied under isothermal and non-isothermal conditions. Differential thermal analysis of MAP showed, in addition to the exotherm due to decomposition, another exotherm at 408° which was observed for the first time. Chemical analysis and the infrared spectrum of the residue left behind after the decomposition proved it to contain NH4ClO4. The results have been explained on the basis of a methyl group transfer in addition to proton transfer in the decomposition process.

Electron spin resonance study of copper(II) doped ferroelectric ammonium sulphate

Single crystal electron spin resonance studies of Cu2+ doped ferroelectric ammonium sulphate ((NH4)2SO4, Tc = 223 K) are reported at 300 and 77 K. The Cu2+ ion is found to enter the lattice interstitially with a trigonal bipyramidal coordination. Proton superhyperfine interaction is found for magnetic field directions close to the a-axis. Changes are observed in the 77 K recordings indicating a distortion of the trigonal bipyramid consistent with crystal structure data. An increase of the proton superhyperfine constant in the ferroelectric phase is indicative of stronger hydrogen bonding. The Cu2+ ion doped as an impurity in a trigonal bipyramid environment in a diamagnetic host lattice is reported for the first time.

Negative differential resistance in GaN nanocrystals above room temperature

Negative differential resistance (NDR) has been observed for the first time above room temperature in gallium nitride nanocrystals synthesized by a simple chemical route. Current-voltage characteristics have been used to investigate this effect through a metal-semiconductor-metal (M-S-M) configuration on SiO2. The NDR effect is reversible and reproducible through many cycles. The threshold voltage is similar to 7 V above room temperature.

Thermal expansion and a new phase transition in pyroelectric LiKSO4

Single crystal macroscopic thermal expansion coefficient measurements have been made on uniaxial lithium potassium sulphate crystal both along and normal to the six fold axis, employing Fizeau’s interferometer method. Measurements were made in the range of −120°C to 500°C. The results show that lithium potassium sulphate exhibits two major anomalies in its expansion coefficients around −95°C and 422°C respectively, the one at −95°C has been observed for the first time. The nature of dimensional changes of the crystal at the upper and lower transition points are opposite in nature. The crystal shows considerable lattice anisotropy. Megaw’s tilt concept has been invoked to explain the relative magnitudes of expansion coefficients alonga andc directions. Structural features responsible for the absence of ferroelectricity in this crystal have been pointed out.

Dilute solution properties of methyl methacrylate�acrylonitrile copolymer (MA1)

This paper deals with studies on the dilute solution properties of methyl methacrylate�acrylonitrile copolymer of 0.289 mole fraction (mf) of acrylonitrile composition. Mark�Houwink parameters for this copolymer have been evaluated in acetonitrile (MeCN), 2-butanone (MEK), dimethylformamide (DMF) and γ-butyrolactone (γ-BL). The solvent power is found to be in the order of MEK < MeCN < DMF < γ-BL at 30°C. Herein, probably for the first time, the steric factor for the copolymer is found to be lower than that for the parent homopolymers and the excess interaction parameter, �AB is found to be negative. This probably suggests that the units are compatible to each other.

An ethnobotanical study of traditional anti-inflammatory plants used by the Lohit community of Arunachal Pradesh, India

Aim of the study: Most people especially in rural areas depend on herbal medicines to treat many diseases including inflammation-related ailments such as rheumatism, muscle swelling, cut wound, accidental bone fracture, insect bites, pains and burn by fire and hot water. The objectives of this study were: to catalog ethno-medicinal plants of Lohit community, ecological status, indigenous folk medicinal uses, morphological parts used and to determine their reported pharmacological studies. Materials and methods: The ethnobotanical information on traditional medicinal plants exclusively used for management of inflammation-related ailments by the Khampti community of Arunachal Pradesh, India was based on first-hand field survey work through semi-structured interviews. Results and conclusion: A total of 34 species in 32 genera and 22 families were encountered during the field survey. Botanical families such as Asteraceae, Euphorbiaceae, Zingiberaceae and Lamiaceae were represented by the highest numbers of species reported in this study. Thirteen plant species, namely: Bombax ceiba, Canarium strictum, Chloranthus erectus, Xanthium indicum, Lycopodium clavatum, Coleus blumei, Batrachospermum atrum, Chlorella vulgaris, Marchantia palmata, Marchantia polymorpha, Eria pannea, Sterculia villosa and Alpinia galanga are reported for the first time for the treatment of inflammation-related diseases.

Comment on "Pseudoelasticity of Cu-Zr nanowires via stress-induced martensitic phase transformations"

Recently, a novel stress-induced phase transformation in an initial < 100 >/{100} B2-CuZr nanowire has been reported for the first time [Sutrakar and Mahapatra, Mater. Lett. 63, 1289 (2009)]. Following this, a martenisitic phase transformation in Cu-Zr nanowire was shown [Cheng et al., Appl. Phys. Lett. 95, 021911 (2009)] using the same idea (Sutrakar and Mahapatra, Mater. Lett. 63, 1289 (2009)]. The pseudoelastic recovery of the bct phase of Cu-Zr by unloading has also been shown [Cheng et al., Appl. Phys. Lett. 95, 021911 (2009)]. They also tested the epitaxial bain path [Alippi et al., Phys. Rev. Lett. 78, 3892 (1997)] and reported that the bct phase in the nanowire is metastable, whereas the bulk counterpart is unstable. This aspect is re-examined in this comment with corrected results.

Polyvanadate-stimulated NADH oxidation by plasma membranes-The need for a mixture of deca and meta forms of vanadate

Polyvanadate solutions obtained by extracting vanadium pentoxide with dilute alkali over a period of several hours contained increasing amounts of decavanadate as characterized by NMR and ir spectra. Those solutions having a metavanadate:decavanadate ratio in the range of 1-5 showed maximum stimulation of NADH oxidation by rat liver plasma membranes. Reduction of decavanadate, but not metavanadate, was obtained only in the presence of the plasma membrane enzyme system. High simulation of activity of NADH oxidation was obtained with a mixture of the two forms of vanadate and this further increased on lowering the pH. Addition of increasing concentrations of decavanadate to metavanadate and vice versa increased the stimulatory activity, reaching a maximum when the metavanadate:decavanadate ratio was in the range of 1-5. Increased stimulatory activity can also be obtained by reaching these ratios by conversion of decavanadate to metavanadate by alkaline phosphate degradation, and of metavanadate to decavanadate by acidification. These studies show for the first time that both deca and meta forms of vanadate present in polyvanadate solutions are needed for maximum activity of NADH oxidation.

Successful recovery of preimplantation embryos by nonsurgical uterine flushing in the bonnet monkey

A major limitation to progress in primate embryology is the lack of an adequate supply of preimplantation embryos. We describe a method for recovering preimplantation-embryos in bonnet monkeys (Macaca radiata ) using a nonsurgical uterine flushing technique similar to the one previously employed in rhesus monkeys. Forty cyclic females were screened for cervical cannulation, and 10% of these had an impassable cervix. Eleven females suitable for cannulation were selected, and 27 menstrual cycles were monitored over a 5-mo period. Seventy-one percent of the cycles showed estrogen peaks, which were observed between Days 9 and 14 of the cycle. Following natural mating, uterine flushings were performed on Days 5 to 8 of pregnancy (Day 0 = the day following the estrogen peak). Of the 27 recovery attempts, 9 (33.3%) resulted in the recovery of ovulation products, including those of an unfertilized oocyte and empty zona (2 cases), retarded cleavage-stage (4 to 8-cell) embryos (4 cases), morula (1 case) and blastocysts (2 cases). These results show, for the first time, that the nonsurgical uterine flushing technique can be successfully performed to recover uterine-stage preimplantation embryos from bonnet monkeys.

Comparative sequence analysis and expression in E-coli of the subgroup I-specific antigen VP6 from a G2 serotype human rotavirus IS2

VP6, the intermediate capsid protein of the virion, specifies subgroup specificity of rotavirus, It is also the most conserved, both at nucleotide and amino acid levels, among group A rotaviruses and is the target of choice for rotavirus detection, In this study we report the sequence of the subgroup I (SGI)-specific VP6 from the serotype G2 strain IS2 isolated from a child suffering from acute diarrhoea in Bangalore ana its comparison with the published VP6 sequences. Interestingly, IS2 gene 6 shared highest homology with that from bovine UK strain and the protein contained substitutions by lysine at amino acid positions 97 and 134, In contrast, the amino acids Met and Glu/Asp at these respective positions are highly conserved in all the other group A rotaviruses sequenced so far, These observations have obvious implications for the evolution of serotype G2 and G2-like strains circulating in India, The SGI VP6, of a human rotavirus, possessing epitopes that are conformationally similar to those found in the native protein in the virion, was successfully expressed in E. coli and purified for the first time by single-step affinity chromatography.

X-ray studies on crystalline complexes involving amino acids and peptides. XXIII. Variability in ionization state, conformation and molecular aggregation in the complexes of succinic acid with DL- and L-lysine

Crystalline complexes of succinic acid with DL- and L-lysine have been prepared and analysed by X-ray diffraction. DL-Lysine complex: C6HIsN202 + 1 2- 1 ~C4H404 .~C4H604, Mr -- 264"2, PI, a = 5"506 (4), =8.070(2), c=14.089(2) A,, a=92.02(1), /3= 100"69 (3), y = 95"85 (3) ~>, Z = 2, Dx = 1"44 g cm -3, R = 0.059 for 2546 observed reflections. Form I of the e-lysine complex: C6HIsN20-, ~ .C4H504, Mr = 264.2, P1, a = 5" 125 (2), b = 8"087 (1), c = 8"689 (1) A,, a = 112.06 (1), /3 = 99.08 (2), y = 93"77(2) °, Z--l, D,,,=1"34(3), Dx=l"34gcm 3 R = 0.033 for 1475 observed reflections. Form II of + I 2- the e-lysine complex: C6H15N202 .,iC4H404 .- 1 I ") 4C4H604.4(C4HsO4""H'"CaH404)" , Mr = 264"2, P1, a = 10.143 (4), b = 10.256 (2), c = 12"916 (3) A,, a = 105.00 (2),/3 = 99-09 (3), y = 92"78 (3)::, Z = 4, Dm= 1"37(4), D,.= 1.38gcm 3, R=0.067 for 2809 observed reflections. The succinic acid molecules in the structures exhibit a variety of ionization states. Two of the lysine conformations found in the complexes have been observed for the first time in crystals containing lysine. Form II of the L-lysine complex is highly pseudosymmetric. In all the complexes, unlike molecules aggregate into separate alternating layers. The basic element of aggregation in the lysine layer in the complexes is an S2-type head-to-tail sequence. This element combines in different ways in the three structures. The basic element of aggre gation in the succinic acid layer in the complexes is a hydrogen-bonded ribbon. The ribbons are interconnected indirectly through amino groups in the lysine layer.

4-Nitro and 4-chloro pyridine-N-oxide complexes of lanthanide perchlorates

Adducts of lanthanide perchlorates with 4-nitro and 4-chloro pyridine-Noxides (4-NPNO and 4-CPNO respectively) have been synthesised for the first time and characterised by analysis, electrolytic conductance, infrared, proton-NMR and electronic spectral data. The complexes are of the compositions Ln2(NPNO)15 (ClO4)6 (Ln = La, Pr, Nd and Gd), Tb(NPNO), (C1O4)6), Ln2(NPNO)13 (C1O4)6) (Ln = Dy, Ho, and Yb); Ln (CPNO)8 (C104)3) (Ln = La, Pr, Nd, Tb, Dy, Ho and Yb) and Ln(CPNO), (C1O4)3) (Ln = Sm and Gd). Conductivity and IR data provide evidence for the non-coordinated nature of the perchlorate groups. IR and NMR spectra suggest coordinationvia the oxygen of the N-oxide group. Electronic spectral shapes of the Nd+3 and Ho+3 complexes are interpreted in terms of eight-and seven-coordinate environments in the case of 4-NPNO complexes and eight-coordination in the case of 4-CPNO complexes. IR data indicate bridged structure in NPNO complexes of lanthanides other than Tb.

Synthesis, characterization, thermal degradation, and comparative chain dynamics studies of weak-link polysulfide polymers

Synthesis, spectroscopic and thermal characterization of two new classes of polysulfide polymers: poly[1(phenoxymethyl) ethylene polysulfide] (PPMEP), and poly [1-(phenoxy) ethylene polysulfide] (PPEP) is presented. The direct pyrolysis mass spectrometry (DP-MS) technique, used to study the thermal degradation behavior of these polysulfide polymers, indicated that the polymers underwent degradation through the weak-links scission. The thermal stability of the polysulfide polymers decreased as the ``rank'' (number of sulfur atoms in the polysulfide linkage; n=1, 2, 4) increased. The main-chain flexibility of these polysulfide polymers in terms of their C-13 NMR spinlattice relaxation time (T-1) measurements on the backbone methine (-CH-) and methylene (-CH2-) carbons are reported here for the first time. A comparative study of the solution chain dynamics indicated that it increased as ``rank'' of the polysulfide linkages decreased as well as by introducing side chain spacers such as, ether (-O-) or methyleneoxy (-CH2O-) groups.

Glycodelin A triggers T cell apoptosis through a novel calcium-independent galactose-binding lectin activity

Glycodelin A (GdA) is one of the progesterone inducible endometrial factors that protect the fetal semiallograft from maternal immune rejection. The immumoregulatory effects of GdA are varied, with diverse effects on the fate and function of most immune cell types. Its effects on T cells are particularly relevant as it is capable of regulating T cell activation, differentiation, as well as apoptosis. We have previously reported that GdA triggers mitochondrial stress and apoptosis in activated T cells by a mechanism that is distinct and independent of its effects on T cell activation. In this study we describe the characterization of a cell surface receptor for GdA on T cells. Our results reveal a novel calcium-independent galactose-binding lectin activity of GdA, which is responsible for its apoptogenic function. This discovery adds GdA to a select group of soluble immunoregulatory lectins that operate within the feto-placental compartment, the only other members being the galectin family proteins. We also report for the first time that both CD4(+) and CD8(+) T cell subsets are equally susceptible to inhibition with GdA, mediated by its novel lectin activity. We demonstrate that GdA selectively recognizes complex-type N-linked glycans on T cell surface glycoproteins. and propose that the galectin-1 glycoprotein receptor CD7 maybe a novel target for GdA on T cells. This study, for the first time, links the lectin activity of GdA to its biological function.