Energetics of lower tropospheric ultra-long waves: A key to intra-seasonal variability of Indian monsoon

Analysis of fifty four (1951-2004) years of daily energetics of zonal waves derived from NCEP/ NCAR wind (u and v) data and daily rainfall received over the Indian landmass (real time data) during southwest monsoon season (1 June-30 September) indicate that energetics (momentum transport and kinetic energy) of lower tropospheric ultra-long waves (waves 1 and 2) of low latitudes hold a key to intra-seasonal variability of monsoon rainfall over India. Correlation coefficient between climatology of daily (122 days) energetics of ultra-long waves and climatology of daily rainfall over Indian landmass is 0.9. The relation is not only significant but also has a predictive potential. The normalised plot of both the series clearly indicates that the response period of rainfall to the energetics is of 5-10 days during the onset phase and 4-7 days during the withdrawal phase of monsoon over India. During the established phase of monsoon, both the series move hand-in-hand. Normalised plot of energetics of ultra-long waves and rainfall for individual year do not show marked deviation with respect to climatology. These results are first of its kind and are useful for the short range forecast of rainfall over India

Energetics of lower tropospheric planetary waves over mid latitudes: Precursor for Indian summer monsoon

Based on NCEP/NCAR reanalysis data, kinetic energy and momentum transport of waves 0 to 10 at 850 hPa level are computed from monthly mean zonal (u) and meridional (v) components of wind from equator to 90°N. Fourier technique is used to resolve the wind field into a spectrum of waves: Correlation analysis between All India Seasonal Monsoon Rainfall (AISMR) and energetics of the waves indicates that effective kinetic energy of waves 1, 3 and 4 around 37.5°N in February has significant correlation (99.9) with the subsequent AISMR. A simple linear regression equation between the effective kinetic energy of these three waves and AISMR is developed. Out of 47 years' (1958-2004) data, 32 years (1958-1989) are utilized for developing the regression model and the remaining 15 years (1990-2004) are considered for its verification. Predicted AISMR is in close agreement with observed AISMR. The regression equation based on the dynamics of the planetary waves is thus useful for Long Range Forecasting (LRF) of AISMR. Apart from the regression equation, the study provides qualitative predictors. The scatter diagram between AISMR and effective kinetic energy of waves 1, 3 and 4 around 37.5°N indicates that if the kinetic energy is more (less) than 5 m2s-2, the subsequent monsoon will be good (weak). Stream function fields indicate that high latitude trough axis along 40°E (70°E) leads to a good (weak) monsoon over India

Synthesis of Heterogeneous Li4Ti5O12 Nanostructured Anodes with Long-Term Cycle Stability

The 0D-1D Lithium titanate (Li4Ti5O12) heterogeneous nanostructures were synthesized through the solvothermal reaction using lithium hydroxide monohydrate (Li(OH)·H2O) and protonated trititanate (H2Ti3O7) nanowires as the templates in an ethanol/water mixed solvent with subsequent heat treatment. A scanning electron microscope (SEM) and a high resolution transmission electron microscope (HRTEM) were used to reveal that the Li4Ti5O12 powders had 0D-1D heterogeneous nanostructures with nanoparticles (0D) on the surface of wires (1D). The composition of the mixed solvents and the volume ratio of ethanol modulated the primary particle size of the Li4Ti5O12 nanoparticles. The Li4Ti5O12 heterogeneous nanostructures exhibited good capacity retention of 125 mAh/g after 500 cycles at 1C and a superior high-rate performance of 114 mAh/g at 20C

Polymorphic variants of SCN1A and EPHX1 influence plasma carbamazepine concentration, metabolism and pharmacoresistance in a population of Kosovar Albanian epileptic patients

Aim The present study aimed to evaluate the effects of gene variants in key genes influencing pharmacokinetic and pharmacodynamic of carbamazepine (CBZ) on the response in patients with epilepsy. Materials & Methods Five SNPs in two candidate genes influencing CBZ transport and metabolism, namely ABCB1 or EPHX1, and CBZ response SCN1A (sodium channel) were genotyped in 145 epileptic patients treated with CBZ as monotherapy and 100 age and sex matched healthy controls. Plasma concentrations of CBZ, carbamazepine-10,11-epoxide (CBZE) and carbamazepine-10,11-trans dihydrodiol (CBZD) were determined by HPLC-UV-DAD and adjusted for CBZ dosage/kg of body weight. Results The presence of the SCN1A IVS5-91G>A variant allele is associated with increased epilepsy susceptibility. Furthermore, carriers of the SCN1A IVS5-91G>A variant or of EPHX1 c.337T>C variant presented significantly lower levels of plasma CBZ compared to carriers of the common alleles (0.71±0.28 vs 1.11±0.69 μg/mL per mg/Kg for SCN1A IVS5-91 AA vs GG and 0.76±0.16 vs 0.94±0.49 μg/mL per mg/Kg for EPHX1 c.337 CC vs TT; PG showed a reduced microsomal epoxide hydrolase activity as reflected by a significantly decreased ratio of CBZD to CBZ (0.13±0.08 to 0.26±0.17, pT SNP and SCN1A 3148A>G variants were not associated with significant changes in CBZ pharmacokinetic. Patients resistant to CBZ treatment showed increased dosage of CBZ (657±285 vs 489±231 mg/day; P<0.001) but also increased plasma levels of CBZ (9.84±4.37 vs 7.41±3.43 μg/mL; P<0.001) compared to patients responsive to CBZ treatment. CBZ resistance was not related to any of the SNPs investigated. Conclusions The SCN1A IVS5-91G>A SNP is associated with susceptibility to epilepsy. SNPs in EPHX1 gene are influencing CBZ metabolism and disposition. CBZ plasma levels are not an indicator of resistance to the therapy

Dielectric study of formamide, N-methyl-formamide and N,N-dimethylformamide

613-615Complex permittivity spectra of formamide, N-methylformamide and N,N-dimethylformamide have been determined in the frequency range to MHz-10 GHz using time domain reflectometry technique at different temperatures. Static dielectric constant (ɛo) of formamide and N-methylformamide is 64% and 78% respectively larger than the corresponding value for N,N-dimethylformamide. The activation energies (Hɛ) for these amides are also reported

2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz)-derived [Ru-II(tptz)(acac)(CH3CN)](+) and mixed-valent [(acac)(2)Ru-III{(mu-tptz-H+)(-)}Ru-II(acac)(CH3CN)](+)

Mononuclear [Ru-II(tptz)(acac:)(CH3CN)]ClO4 ((ClO4)-Cl-[1]) and mixed-valent dinuclear [(acac)(2)Ru-III{(mu-tptz-H+)(-)}Ru-II(acac)(CH3CN)]ClO4 ([5]ClO4; acac = acetylacetonate) complexes have been synthesized via the reactions of Ru-II(acac)2(CH3CN)(2) and 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz), in 1:1 and 2:1 molar ratios, respectively. In [1]ClO4, tptz binds with the Ru-II ion in a tridentate N,N,N mode (motif A), whereas in [5]ClO4, tptz: bridges the metal ions unsymmetrically via the tridentate neutral N,N,N mode with the Ru-II center and cyclometalated N,C- state with the Ru-III site (motif F). The activation of the coordinated nitrile function in [1]ClO4 and [5]ClO4 in the presence of ethanol and alkylamine leads to the formation of iminoester ([2]ClO4 and [7]ClO4) and amidine ([4]ClO4) derivatives, respectively. Crystal structure analysis of [2]ClO4 reveals the formation of a beautiful eight-membered water cluster having a chair conformation. The cluster is H-bonded to the pendant pyridyl ring N of tptz and also with the O atom of the perchlorate ion, which, in turn, makes short (C-H-----O) contacts with the neighboring molecule, leading to a H-bonding network. The redox potentials corresponding to the (RuI)-I-I state in both the mononuclear {[(acac)(tptz)Ru-II-N=-C-CH3]ClO4 ([1]ClO4) >> [(acac)(tptz)Ru-II-NH=C(CH3)-OC2H5]ClO4 ([2]ClO4) > [(acac)(tptz)(RuNH2)-N-II-C6H4(CH3)]ClO4 ([3]ClO4) > [(acac)(tptz)Ru-II-NH=C(CH3)-NHC2H5]ClO4 ([4]ClO4)} and dinuclear {[(acac)(2)Ru-III-{mu-tptz-H+)(-)}Ru-II(acac)(N equivalent to C-CH3)]ClO4 {(mu-tptz-H+)(-)}Ru-II(acac)(N equivalent to C-CH3)]ClO4 ([5]ClO4), [(acac)(2)Ru-III[(mu-tptz-H+(N-O ([6]ClO4), [(acac)(2)Ru-III{(mu-tptz-H+)(-)}Ru-II(acac)(NH=C(CH3)-OC2H5)]ClO4([7]ClO4), and [(acac)(2)Ru-III{(mu-tptz-H+)(-)}Ru-II(acac)(NC4H4N)]ClO4 ([8]ClO4), complexes vary systematically depending on the electronic nature of the coordinated sixth ligands. However, potentials involving the Ru-III center in the dinuclear complexes remain more or less invariant. The mixed-valent (RuRuIII)-Ru-II species ([5]ClO4-[8]ClO4) exhibits high comproportionation constant (K-c) values of 1.1 X 10(12)-2 x 109, with substantial contribution from the donor center asymmetry at the two metal sites. Complexes display Ru-II- and Ru-III-based metal-to-ligand and ligand-to-metal charge-transfer transitions, respectively, in the visible region and ligand-based transitions in the UV region. In spite of reasonably high K, values for [5]ClO4[8]ClO4, the expected intervalence charge-transfer transitions did not resolve in the tpical near-IR region up to 2000 nm. The paramagnetic (RuRuIII)-Ru-II species ([5]ClO4-[8]ClO4) displays rhombic electron paramagnetic resonance (EPR) spectra at 77 K ( similar to 2.15 and Delta g similar to 0.5), typical of a low-spin Ru-III ion in a distorted octahedral environment. The one-electron-reduced tptz complexes [RuII(tptz center dot-)(acac)(CH3CN)] (1) and [(acac)(2)Ru-III{mu-tptz-H+)(center dot 2-)}-Ru-II(acac)(CH3CN)] (5), however, show a free-radical-type EPR signal near g = 2.0 with partial metal contribution

Selective recognition of fluoride and acetate by a newly designed ruthenium framework: experimental and theoretical investigations

An effective anion sensor, [Ru-II(bpy)(2)(H2L-)](+) (1(+)), based on a redox and photoactive {Ru-II(bpy)(2)} moiety and a new ligand (H3L = 5-(1H-benzo[d]imidazol-2-yl)-1H-imidazole-4-carboxylic acid), has been developed for selective recognition of fluoride (F-) and acetate (OAc-) ions. Crystal structures of the free ligand, H3L and [1](ClO4) reveal the existence of strong intramolecular and intermolecular hydrogen bonding interactions. The structure of [1](ClO4) shows that the benzimidazole N-H of H2L- is hydrogen bonded with the pendant carboxylate oxygen while the imidazole N-H remains free for possible hydrogen bonding interaction with the anions. The potential anion sensing features of 1(+) have been studied by different experimental and theoretical (DFT) investigations using a wide variety of anions, such as F-, Cl-, Br-, I-, HSO4-, H2PO4-, OAc- and SCN-. Cyclic voltammetry and differential pulse voltammetry established that 1(+) is an excellent electrochemical sensor for the selective recognition kof F- and OAc- anions. 1(+) is also found to be a selective colorimetric sensor for F- or OAc- anions where the MLCT band of the receptor at 498 nm is red shifted to 538 nm in the presence of one equivalent of F- or OAc- with a distinct change in colour from reddish-orange to pink. The binding constant between 1(+) and F- or OAc- has been determined to be logK = 7.61 or 7.88, respectively, based on spectrophotometric titration in CH3CN. The quenching of the emission band of 1(+) at 716 nm (lambda(ex) = 440 nm, Phi = 0.01 at 298 K in CH3CN) in the presence of one equivalent of F- or OAc-, as well as two distinct lifetimes of the quenched and unquenched forms of the receptor 1(+), makes it also a suitable fluorescence-based sensor. All the above experiments, in combination with H-1 NMR, suggest the formation of a 1 : 1 adduct between the receptor (1(+)) and the anion (F- or OAc-). The formation of 1 : 1 adduct {[1(+).F-] or [1(+).OAc-]} has been further evidenced by in situ ESI-MS(+) in CH3CN. Though the receptor, 1(+), is comprised of two N-H protons associated with the coordinated H2L- ligand, only the free imidazole N-H proton participates in the hydrogen bonding interactions with the incoming anions, while the intramolecularly hydrogen bonded benzimidazole N-H proton remains intact as evidenced by the crystal structure of the final product (1). The hydrogen bond mediated anion sensing mechanism, over the direct deprotonation pathway, in 1(+) has been further justified by a DFT study and subsequent NBO analysis

Metal-induced reductive ring opening of 1,2,4,5-tetrazines: Three resulting coordination alternatives, including the new non-innocent 1,2-diiminohydrazido(2-) bridging ligand system

Reaction of 3,6-diaryl-1,2,4,5-tetrazines (aryl = R = phenyl, 2-furyl or 2-thienyl) with 2 equiv of Ru(acac)(2)(CH3-CN)(2) results in reductive tetrazine ring opening to yield diruthenium complexes [(acac)(2)Ru-III(dih-R2-)Ru-III(acac)(2)] bridged by the new 1,2-diiminohydrazido(2-) (dih-R2- = HNC(R)NNC(R)NH2-) ligands. rac/meso diastereoisomers could be detected and separated for the compounds with R = phenyl and 2-thienyl, all species are diamagnetic and were characterized by H-1 NMR spectroscopy. Crystal structure determination of the meso isomers with R = phenyl and 2-thienyl confirmed the 1,2-diiminohydrazido formulation through long N-N (approximate to 1.40 angstrom) and short C=N(H) bonds (approximate to 1.31 angstrom), implying two bridged ruthenium(III) centers at about 4.765 angstrom distance with strong antiferromagnetic coupling. The complexes undergo two reversible and well-separated one-electron reduction and oxidation processes, respectively. EPR Spectroscopy of the paramagnetic intermediates with comproportionation constants K-c > 10(12) and UV-vis-NIR spectroelectrochemistry were used to identify the accessible redox states as [(acac)(2)Ru-II(dih-R2-)Ru-II(acac)(2)](2-), [(acac)(2)Ru-II(dih-Rcenter dot-)Ru-II(acac)(2)](-), [(acac)(2)Ru-II(dih-R2-)Ru-III(acac)(2)], [(acac)(2)Ru-III(dih-Rcenter dot-)Ru-III(acac)(2)](+), and [(acac)(2)Ru-III(dih-R)Ru-III(acac)(2)](2+). While the UV-vis-NIR spectroscopic response of [(acac)(2)Ru(dih-R)Ru(acac)(2)](0/-/2-) is very similar to that of [(bpy)(2)Ru(adc-R)Ru(bpy)(2)](4+/3+/2+), adc-R-2- = 1,2-diacylhydrazido(2-), the EPR result indicating ligand-centered spin for [(acac)(2)Ru-II(dih-Rcenter dot-)Ru-II(acac)(2)](-) despite deceptive NIR absorptions around 1400 nm reveals distinct differences in the electronic structures