Crystal structure of nonadentate tricompartmental ligand derived from pyridine-2,6-dicarboxylic acid: Spectroscopic, electrochemical and thermal investigations of its transition metal(II) complexes

The coordinating behavior of a new dihydrazone ligand, 2,6-bis(3- methoxysalicylidene)hydrazinocarbonylpyridine towards manganese(II), cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) has been described. The metal complexes were characterized by magnetic moments, conductivity measurements, spectral (IR, NMR, UV-Vis, FAB-Mass and EPR) and thermal studies. The ligand crystallizes in triclinic system, space group P-1, with α = 98.491(10)°, β = 110.820(10)° and γ = 92.228(10)°. The cell dimensions are a = 10.196(7) , b = 10.814(7) , c = 10.017(7) , Z = 2 and V = 1117.4(12). IR spectral studies reveal the nonadentate behavior of the ligand. All the complexes are neutral in nature and possess six-coordinate geometry around each metal center. The X-band EPR spectra of copper(II) complex at both room temperature and liquid nitrogen temperature showed unresolved broad signals with giso = 2.106. Cyclic voltametric studies of copper(II) complex at different scan rates reveal that all the reaction occurring are irreversible. © 2011 Elsevier B.V

NMR and NQR Fluctuation Effects in Layered Superconductors

We study the effect of thermal fluctuations of the s-wave order parameter of a quasi two dimensional superconductor on the nuclear spin relaxation rate near the transition temperature Tc. We consider both the effects of the amplitude fluctuations and the Berezinskii-Kosterlitz-Thouless (BKT) phase fluctuations in weakly coupled layered superconductors. In the treatment of the amplitude fluctuations we employ the Gaussian approximation and evaluate the longitudinal relaxation rate 1/T1 for a clean s-wave superconductor, with and without pair breaking effects, using the static pair fluctuation propagator D. The increase in 1/T1 due to pair breaking in D is overcompensated by the decrease arising from the single particle Green's functions. The result is a strong effect on 1/T1 for even a small amount of pair breaking. The phase fluctuations are described in terms of dynamical BKT excitations in the form of pancake vortex-antivortex (VA) pairs. We calculate the effect of the magnetic field fluctuations caused by the translational motion of VA excitations on 1/T1 and on the transverse relaxation rate 1/T2 on both sides of the BKT transitation temperature T(BKT)<Tc. The results for the NQR relaxation rates depend strongly on the diffusion constant that governs the motion of free and bound vortices as well as the annihilation of VA pairs. We discuss the relaxation rates for real multilayer systems where the diffusion constant can be small and thus increase the lifetime of a VA pair, leading to an enhancement of the rates. We also discuss in some detail the experimental feasibility of observing the effects of amplitude fluctuations in layered s-wave superconductors such as the dichalcogenides and the effects of phase fluctuations in s- or d-wave superconductors such as the layered cuprates.Comment: 38 pages, 12 figure

The Molecular Epidemiology of Clostridioides difficile Infection in Central India: A Prospective Observational Cohort Study

This prospective observational cohort study aimed to establish and compare baseline rates of Clostridioides difficile infection (CDI) in community and hospitalized patients in Nagpur and rural Melghat Maharashtra, including adults aged ≥18 years with a diagnosis of diarrhoea as defined as 3 or more loose stools in a 24 h period. All diarrhoeal samples were tested for CDI using the C. diff Quik Chek Complete enzyme immunoassay. C. difficile-positive stool samples were characterised by toxigenic culture, antimicrobial susceptibility testing and PCR ribotyping. C. difficile testing was performed on 1683 patients with acute diarrhoea. A total of 54 patients (3.21%; 95% CI: 2.42–4.17) tested positive for both the GDH antigen and free toxin. The risk factors for CDI included the presence of co-morbidities, antibiotic usage, and immunosuppression. The detected PCR ribotypes included 053-16, 017, 313, 001, 107, and 216. Our findings show that toxigenic C. difficile is an important but neglected aetiologic agent of infective diarrhoea in Central India. These results underscore the need to enhance the awareness and testing of patients with diarrhoea in India regarding the presence of toxigenic C. difficile, particularly in high-risk individuals with multiple co-morbidities, immunosuppression, and recent or ongoing antibiotic exposure or hospitalization

The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set

Background Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables. Methods Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set. Results Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001). Conclusions The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy

Synthesis and spectral investigation of manganese(II), cadmium(II) and oxovanadium(IV) complexes with 2,6-diacetylpyridine bis(2-aminobenzoylhydrazone): crystal structure of manganese(II) and cadmium(II) complexes

The chelating behavior of 2,6-diacetylpyridine bis(2-aminobenzoylhydrazone) (H2dapa) towards manganese(II), cadmium(II) and oxovanadium(IV) ions has been studied by elemental analyses, conductance measurements, magnetic properties and spectral (IR, 1H NMR, UV–Vis and EPR) studies. The IR spectral studies suggest the pentadentate nature of the ligand with pyridine nitrogen, two azomethine nitrogens and two carbonyl oxygen atoms as the ligating sites. Six coordinate structure for [VO(H2dapa)]SO4 · H2O and seven coordinate structures for [Mn(H2dapa)(Cl)(H2O)]Cl · 2H2O and [Cd(H2dapa)Cl2] · H2O complexes have been proposed. Pentagonal bipyramidal geometry for [Mn(H2dapa)(Cl)(H2O)]Cl · 2H2O and [Cd(H2dapa)(Cl2)] · H2O complexes was confirmed by single crystal analysis. The X-band EPR spectra of the oxovanadium(IV) and manganese(II) complexes in the polycrystalline state at room (300 K) and also at liquid nitrogen temperature (77 K) were recorded and their salient features are reported

Ga46Sb54 Material for Fast Switching and Pb Free Soldering Reflow Process Complying Phase Change Memory

The properties of Ga46Sb54 material have been studied with respect to its usefulness for phase change memory PCM . An unusual inverse optical contrast where the crystalline phase has lower reflectance than amorphous phase compared to typical phase change materials was observed. The high crystallization temperature of thin film ensures this material s excellent data retention. This material has been demonstrated to pass 260 amp; 9702;C solder reflow thermal cycling as determined from optical laser testing and also prototype PCM device testing. The short SET time of 60 ns realized in Ga46Sb54 devices makes this material very attractive with respect to fast switching and high temperature data retentio