153 research outputs found

    Influence of elevated carbon dioxide concentrations on methane emission and its associated soil microflora in rice ecosystem

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    The dynamics of methane emission and its associated soil microflora in rice ecosystem as a response to elevated CO2 concentrations were studied in open top chamber (OTC) conditions. The treatments consisted of three levels of CO2 (396, 550 and 750 µmol mol-1) and three levels of nitrogen (0, 150 and 200 kg ha-1) and replicated five times in a completely randomized design. The data showed that elevated [CO2] significantly (P ? 0.01) increased the DOC throughout the cropping period with the values ranging from 533 to 722 mg L-1 and 368 to 501 mg L-1 in C750 and Camb, respectively. Methane emission rates were monitored regularly during the experiment period and it was revealed that elevated [CO2] had increased the methane emissions regardless of stages of crop growth.  It was observed that methane emissions were significantly higher under [CO2] of 750 µmol mol-1 by 33 to 54 per cent over the ambient [CO2] of 396 µmol mol-1. Consistent with the observed increases in methane flux, the enumeration of methanogens showed a significant (P ? 0.01) increase under elevated [CO2] with the population ranging from 5.7 to 20.1 x 104 CFU g-1 of dry soil and 5.1 to 16.9 x 104 CFU g-1 of dry soil under C750 and Camb concentrations, respectively. Interestingly, even though higher methanotrophs population was recorded under elevated [CO2], it could not circumvent the methane emission. Overall, the results of OTC studies suggest that methane mitigation strategies need to be explored for the future high CO2 environments.

    Heteroleptic copper(I) complexes with coumarin-substituted aminodiphosphine and diimine ligands: synthesis and photophysical studies

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    The synthesis of heteroleptic Cu(I) complexes with coumarin-functionalized aminodiphosphine and diimine ligands is described. The complexes show yellow to deep-red phosphorescence in the solid state at ambient temperature with quantum yields up to 21%. The emission color of the complexes can be tuned by systematic modifications in the ligand system

    Quasistatic Resonators Based Triple-Mode Notched Microstrip Bandpass Filter

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    This article discusses new approach for design and development of triple-mode notched microstrip bandpass filter based on quasistatic resonators(QR). The proposed approach is composed of two Quasistatic resonant elements; Horizontal plane Split ring resonator (HP-SRR), Vertical plane split ring resonator (VP-SRR) and a single asymmetric step impedance resonator (A-SIR) with parallel coupled feed structure. An additional attenuation pole realized by VP-SRR in desired passband, tunes the dual-mode response to triple mode and enhances the 3dB bandwidth without changing the dimensions of basic the filter cell. The HP-SRR realizes a notch at WiMAX band (IEEE 802.11a lower band) in the desired passband. Further by changing the impedance of VP-SRR and HP-SRR both the location of additional attenuation pole frequency and notch band can be controlled. The proposed approach results in compact, notched wideband, filter design

    Crystal structures and magnetic order of La{0.5+delta}A{0.5-delta}Mn{0.5+epsilon}Ru{0.5-epsilon}O{3} (A= Ca, Sr, Ba): Possible orbital glass ferromagnetic state

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    The crystallographic and magnetic properties of La{0.5+delta}A{0.5-delta}Mn{0.5+epsilon}Ru{0.5-epsilon}O{3} (A= Ca, Sr, Ba) were investigated by means of neutron powder diffraction. All studied samples show the orthorhombic perovskite crystal structure, space group Pnma, with regular (Mn,Ru)O{6} octahedra and no chemical ordering of the Mn3+ and Ru4+ ions. Ferromagnetic spin structures were observed below Tc ~ 200-250 K, with an average ordered moment of ~ 1.8-2.0 Bohr magnetons per (Mn,Ru). The observation of long-range ferromagnetism and the absence of orbital ordering are rationalized in terms a strong Mn-Ru hybridization, which may freeze the orbital degree of freedom and broaden the eg valence band, leading to an orbital-glass state with carrier-mediated ferromagnetism

    Monitoring vegetation dynamics using multi-temporal Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) images of Tamil Nadu

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    Vegetation indices serve as an essential tool in monitoring variations in vegetation. The vegetation indices used often, viz., normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) were computed from MODIS vegetation index products. The present study aimed to monitor vegetation's seasonal dynamics by using time series NDVI and EVI indices in Tamil Nadu from 2011 to 2021. Two products characterize the global range of vegetation states and processes more effectively. The data sources were processed and the values of NDVI and EVI were extracted using ArcGIS software. There was a significant difference in vegetation intensity and status of vegetation over time, with NDVI having a larger value than EVI, indicating that biomass intensity varies over time in Tamil Nadu. Among the land cover classes, the deciduous forest showed the highest mean values for NDVI (0.83) and EVI (0.38), followed by cropland mean values of NDVI (0.71) and EVI (0.31) and the lowest NDVI (0.68) and EVI (0.29) was recorded in the scrubland. The study demonstrated that vegetation indices extracted from MODIS offered valuable information on vegetation status and condition at a short temporal time period

    Phase‐Dependent Long Persistent Phosphorescence in Coumarin‐Phosphine‐Based Coinage Metal Complexes

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    A coumarin functionalized aminodiphosphine has been introduced as a bidentate ligand in coinage metal chemistry. Mono-, di-, and trimetallic copper and silver complexes were synthesized with this ligand. The hybrid character of the ligand led to compounds with rich luminescence properties. These include coumarin-based blue fluorescence, observed as a sole emission in solution at room temperature, and green phosphorescence, which is efficient at low temperatures and dominates the spectra of the metal complexes. In the rigid environment of frozen solutions, the green phosphorescence shows an unusually long (for metal complexes) decay on the seconds timescale in high quantum yield. In addition, a red phosphorescence, which may be assigned to the triplet state localized in the phosphine-M3_{3}Cl2_{2} (M=Cu, Ag), is observed for the trinuclear complexes at low temperature. Neither the second-long phosphorescence nor the red emission is observed for the coumarin ligand, thus they must be a result of the coordination to coinage metal clusters. The excited states in these compounds were also investigated by femtosecond transient absorption spectroscopy and quantum chemical calculations

    Effect of growth regulators and micronutrients on quality parameters in cashew (Anacardium occidentale L.)

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    Cashew (Anacardium occidentale L.) is an important tropical nut crop of social and economic importance worldwide. However, the crop is threatened with the low yield. In the present study, an attempt was made to test the effects of plant growth hormones as well as micronutrients on nut and apple quality of cashew var. Bhaskara. Significant differences in kernel weight, shelling percentage, carbohydrates and starch content of cashew kernel and juice content of cashew apple were observed with the foliar application of growth hormones and micronutrients. The foliar application of ethrel @ 50 ppm increased shelling percentage (35.8%), carbohydrate content (21.63%), sugar content (6.26%), protein content (32.4%), starch content (31.42%), juice content (78.3%) and total soluble solids (120 Brix). Further, the foliar spray of zinc sulphate (0.5%) + borax (0.1%) increased shelling (36.13%), protein content (32.15%), starch content (32.03%) among all the treatments tested. Furthermore, higher cashew apple juice content (78%) and total soluble solids (120Brix) was also recorded with the foliar spray of zinc sulphate (0.5%) + borax (0.1%)

    Targeted Deletion of Neuropeptide Y (NPY) Modulates Experimental Colitis

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    Neurogenic inflammation plays a major role in the pathogenesis of inflammatory bowel disease (IBD). We examined the role of neuropeptide Y (NPY) and neuronal nitric oxide synthase (nNOS) in modulating colitis.Colitis was induced by administration of dextran sodium sulphate (3% DSS) or streptomycin pre-treated Salmonella typhimurium (S.T.) in wild type (WT) and NPY (NPY(-/-)) knockout mice. Colitis was assessed by clinical score, histological score and myeloperoxidase activity. NPY and nNOS expression was assessed by immunostaining. Oxidative stress was assessed by measuring catalase activity, glutathione and nitrite levels. Colonic motility was assessed by isometric muscle recording in WT and DSS-treated mice.DSS/S.T. induced an increase in enteric neuronal NPY and nNOS expression in WT mice. WT mice were more susceptible to inflammation compared to NPY(-/-) as indicated by higher clinical & histological scores, and myeloperoxidase (MPO) activity (p<0.01). DSS-WT mice had increased nitrite, decreased glutathione (GSH) levels and increased catalase activity indicating more oxidative stress. The lower histological scores, MPO and chemokine KC in S.T.-treated nNOS(-/-) and NPY(-/-)/nNOS(-/-) mice supported the finding that loss of NPY-induced nNOS attenuated inflammation. The inflammation resulted in chronic impairment of colonic motility in DSS-WT mice. NPY -treated rat enteric neurons in vitro exhibited increased nitrite and TNF-alpha production.NPY mediated increase in nNOS is a determinant of oxidative stress and subsequent inflammation. Our study highlights the role of neuronal NPY and nNOS as mediators of inflammatory processes in IBD
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