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Hydrothermal combustion based ZnO nanoparticles from Croton bonplandianum: Characterization and evaluation of antibacterial and antioxidant potential
No full textThe present study reports facile phytomediated synthesis of ZnO nanoparticles (ZnO NPs) using hydrothermal combustion from Croton bonplandianum Bail. The characterization studies revealed that an average 44 nm size spherical ZnO NPs with high zinc composition having good crystalline nature. FTIR analysis confirmed the presence of functional groups O-H, sp3 C-H bend, and alkoxy C-O functional groups which might be involved in capping and reduction for ZnO NPs synthesis. The biosynthesized ZnO NPs exhibited potent antibacterial activity against Gram-positive and Gram-negative bacteria. The MIC results revealed that ZnO NPs were most effective against Bacillus cereus whereas least sensitive towards Pseudomonas aeruginosa and Vibrio parahaemolyticus. This investigation suggests that biosynthesized ZnO NPs are promising agents for antibacterial and antioxidant applications in the biomedical field
Performance assessment of CHIRPS, MSWEP, SM2RAIN-CCI, and TMPA precipitation products across India
No full textAccurate long-term estimates of precipitation at fine spatiotemporal resolution are vital for several applications ranging from hydrometeorology to climatology. The availability of a good network of rain gauges, and high precipitation variability associated with two annual monsoon systems and complex topography make India a suitable test-bed to assess the performance of any satellite-based precipitation product This study assesses the performance of latest versions of four multi-satellite precipitation products: (i) Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS), (ii) Multi-Source Weighted-Ensemble Precipitation (MSWEP), (iii) SM2RAIN-Climate Change Initiative (SM2RAIN-CCI), and (iv) TRMM Multisatellite Precipitation Analysis (TMPA) across India using gauge-based observations for the period of 1998-2015 at monthly scale. These four multi-satellite precipitation products are essentially based on different algorithms and input data sets. Among these multi-satellite precipitation products, SM2RAIN-CCI is the only product that does not use rain gauge observations for bias adjustment. Results indicate that CHIRPS and TMPA are comparable to gauge-based precipitation estimates at all-India and sub-regional scales followed by MSWEP estimates. However, SM2RAIN-CCI largely underestimates precipitation across the country as compared to gauge-based observations. The systematic error component in SM2RAIN-CCI dominates as compared to random error component, which suggests the need of a suitable bias correction to SM2RAIN-CCI before integrating it in any application. The overall results indicate that CHIRPS data set could be used for long-term precipitation analyses with rather higher confidence
Synthesis and structural characterization of orange red light emitting Sm3+ activated BiOCl phosphor for WLEDs applications
No full textWe report, synthesis of orange red light emitting Sm3+ activated BiOCl phosphors at relatively low temperature (400 degrees C) and shorter duration of 1 h. Rietveld refined results confirmed that all the compounds crystallized in the tetragonal structure with space group P4/nmm (No. 129). Functional group analysis were carried out by Fourier transform infrared (FT-IR) and Raman spectroscopy. The Photoluminescent (PL) experiment results reveal that, an intense PL transition at 598 nm ((4)G(5/2) -> H-6(7/2)) corresponds to orange red emission at lambda(ex) = 408 nm. The maximum emission intensity was observed for BiOCl: Sm3+ (3 mol%) phosphor, above this concentration quenching takes place due to charge exchange with neighboring Sm3+ ions. Time resolved fluorescence spectroscopic result reveals that, the decay curve is bi-exponential in nature and having long lifetime (tau = 0.58 ms). The obtained CIE and CCT values suggest that these phosphors having excellent color purity (similar to 90%) and low correlated color temperature. These results suggest that, Sm3+ activated BiOCl can be a potential red phosphor materials for WLEDs and other optoelectronics applications. (C) 2019 Elsevier B.V. All rights reserved
Combinatorial Design of Molecule using Activity-Linked Substructural Topological Information as Applied to Antitubercular Compounds
No full textBackground: Generating a large number of compounds using combinatorial methods increases the possibility of finding novel bioactive compounds. Although some combinatorial structure generation algorithms are available, any method for generating structures from activity-linked substructural topological information is not yet reported. Objective: To develop a method using graph-theoretical techniques for generating structures of antitubercular compounds combinatorially from activity-linked substructural topological information, predict activity and prioritize and screen potential drug candidates. Methods: Activity related vertices are identified from datasets composed of both active and inactive or, differently active compounds and structures are generated combinatorially using the topological distance distribution associated with those vertices. Biological activities are predicted using topological distance based vertex indices and a rule based method. Generated structures are prioritized using a newly defined Molecular Priority Score (MPS). Results: Studies considering a series of Acid Alkyl Ester (AAE) compounds and three known antitubercular drugs show that active compounds can be generated from substructural information of other active compounds for all these classes of compounds. Activity predictions show high level of success rate and a number of highly active AAE compounds produced high MPS score indicating that MPS score may help prioritize and screen potential drug molecules. A possible relation of this work with scaffold hopping and inverse Quantitative Structure-Activity Relationship (iQSAR) problem has also been discussed. Conclusion: The proposed method seems to hold promise for discovering novel therapeutic candidates for combating Tuberculosis and may be useful for discovering novel drug molecules for the treatment of other diseases as well
Influence of orbital two-channel Kondo effect on anomalous Hall effect in ferrimagnetic composites of LaNiO3 and CoFe2O4
No full textIn this report, we have investigated the magnetoresistance (MR) and Hall effect of the ferrimagnetic composites containing LaNiO3 and CoFe2O4 (CFO) (with CFO content 15% and 20%) which exhibit orbital two-channel Kondo (2CK) effect and therefore pronounced resistivity upturn at low temperature. Both composites manifest a negative to positive crossover in MR with increasing temperature. The MR is described by the Khosla and Fisher model of spin fluctuations scattering of conduction electrons and the two-band theory based on hybridized p-d sub-bands. The Hall resistivity of the composites consists of both ordinary and anomalous part. The negative sign of the ordinary Hall coefficient suggests electrons as the dominating charge carriers. The coefficient of anomalous Hall resistivity (R-S) follows the scaling relation (R-S = a rho(xx) + b rho(2)(xx)) with longitudinal resistivity (rho(xx)) at high temperature above the resistivity upturn. However, at low temperature R-S shows non-monotonous behaviour and deviates from the scaling relation where orbital 2CK effect takes place. More detailed study below the resistivity upturn of the composite with 20% CFO reveals that this deviation occurs around the Kondo temperature. This breakdown of scaling relation around the Kondo temperature indicates the possible influence of orbital 2CK on the anomalous Hall effect
Measurement of the top quark mass in the all- jets final state at root s=13 TeV and combination with the lepton plus jets channel
No full textA top quark mass measurement is performed using 35.9 fb - 1 of LHC proton- proton collision data collected with the CMS detector at v s = 13 TeV. The measurement uses the tt all- jets final state. A kinematic fit is performed to reconstruct the decay of the tt system and suppress themultijet background. Using the ideogram method, the top quark mass ( mt) is determined, simultaneously constraining an additional jet energy scale factor ( JSF). The resulting value of mt = 172.34 +/- 0.20 ( stat+ JSF) +/- 0.70 ( syst) GeV is in good agreement with previous measurements. In addition, a combined measurement that uses the tt lepton+ jets and all- jets final states is presented, using the same mass extraction method, and provides an mt measurement of 172.26 +/- 0.07 ( stat+ JSF) +/- 0.61 ( syst) GeV. This is the first combined mt extraction from the lepton+ jets and all- jets channels through a single likelihood function
Phase diagram of the half-filled ionic Hubbard model in the limit of strong correlations
No full textWe investigate the ionic Hubbard model (IHM) at half-filling in the limit of strong correlations and large ionic potential. The low-energy effective Hamiltonian in this limit, obtained by a similarity transformation, is a modified t-J model with effective second-neighbor hopping terms. We explore the possibilities of d-wave pairing and extended s-wave pairing superconducting (SC) phases on a two-dimensional square lattice at zero temperature within a Gutzwiller projected renormalized mean-field theory. In the sector of solutions that forbid spin-ordering, the system shows a finite nonzero d-wave as well as extended s-wave pairing amplitude for Delta similar to U >> t. The width of the superconducting phase in U - Delta regime shrinks with increase in U and Delta, though the extended s-wave pairing phase is higher in energy than the d-wave pairing superconducting phase. But in a spin-resolved renormalized mean-field calculation, which allows for an antiferromagnetic (AF) order along with the d-wave or extended s-wave pairing, the SC phase is no longer viable and the system shows a direct transition from an AF ordered phase to a paramagnetic band insulator. Except for a thin sliver of a half-metallic AF phase close to the AF transition point, most of the AF ordered phase is a Mott insulator. We benchmarked the AF Mott insulator to band insulator transition within the Gutzwiller projected renormalized mean-field theory against the dynamical mean-field theory solved using continuous time quantum Monte Carlo. Our work suggests that the ground-state phase diagram of the IHM at half-filling in the limit of extreme correlations does not have any SC phase. The SC phase seen in the paramagnetic sector is a metastable phase, being higher in energy than the AF Mott insulator phase
Enantiospecific syntheses of oxacyclodecanes from carvone via mild Lewis acid mediated etherifcation
No full textAn efficient enantiospecific syntheses of oxatri-/tetra-cyclodecanes have been accomplished starting from (R)-carvone. A mild Lewis acid (BF3.OEt2) mediated intramolecular etherification is used as the key step. Structurally aesthetic tri- and tetracyclic ethers have been synthesized
Three-Dimensional Modelling of Heterogeneous Coastal Aquifer: Upscaling from Local Scale
No full textThe aquifer heterogeneity is often simplified while conceptualizing numerical model due to lack of field data. Conducting field measurements to estimate all the parameters at the aquifer scale may not be feasible. Therefore, it is essential to determine the most significant parameters which require field characterization. For this purpose, the sensitivity analysis is performed on aquifer parameters, viz., anisotropic hydraulic conductivity, effective porosity and longitudinal dispersivity. The results of the sensitivity index and root mean square deviation indicated, that the longitudinal dispersivity and anisotropic hydraulic conductivity are the sensitive aquifer parameters to evaluate seawater intrusion in the study area. The sensitive parameters are further characterized at discrete points or at local scale by using regression analysis. The longitudinal dispersivity is estimated at discrete well points based on Xu and Eckstein regression formula. The anisotropic hydraulic conductivity is estimated based on established regression relationship between hydraulic conductivity and electrical resistivity with R-2 of 0.924. The estimated hydraulic conductivity in x and y-direction are upscaled by considering the heterogeneous medium as statistically homogeneous at each layer. The upscaled model output is compared with the transversely isotropic model output. The bias error and root mean square error indicated that the upscaled model performed better than the transversely isotropic model. Thus, this investigation demonstrates the necessity of considering spatial heterogeneous parameters for effective modelling of the seawater intrusion in a layered coastal aquifer
Phenylacetylene as a gas phase sliding balance for solvating alcohols
No full textPhenylacetylene offers two similarly attractive binding sites to OH containing solvent molecules, the phenyl ring and the acetylenic triple bond. By systematically varying the solvent molecule and by methylating aromatic or acetylenic CH groups, the docking preference can be controlled. It ranges from almost exclusive acetylene docking to predominant phenyl docking, depending on how electron density is deposited into the conjugated system and how large the London dispersion interaction is. FTIR spectroscopy of supersonic jet expansions is used to observe the competitive docking preferences in phenylacetylene and some of its methylated derivatives. A new data evaluation procedure that estimates band strength uncertainties based on a Monte Carlo approach is introduced. We test how well two density functionals (B3LYP-D3 and M06-2X) in combination with a def2-TZVP basis set are able to describe the docking switch. B3LYP-D3 is slightly biased towards acetylenic hydrogen bond docking and M06-2X is strongly biased towards phenyl hydrogen bond docking. More accurate theoretical predictions are invited and some previous experimental assignments are questioned