Importance of conduction electron correlation in a Kondo lattice, Ce2CoSi3

Kondo systems are usually described by the interaction of strong correlation induced local moment with the highly itinerant conduction electrons. Here, we study the role of electron correlations among conduction electrons in the electronic structure of a Kondo lattice compound, Ce$_2$CoSi$_3$, using high resolution photoemission spectroscopy and {\it ab initio} band structure calculations, where Co 3$d$ electrons contribute in the conduction band. High energy resolution employed in the measurements helped to reveal signature of Ce 4$f$ states derived Kondo resonance feature at the Fermi level and dominance of Co 3$d$ contributions at higher binding energies in the conduction band. The line shape of the experimental Co 3$d$ band is found to be significantly different from that obtained from the band structure calculations within the local density approximations, LDA. Consideration of electron-electron Coulomb repulsion, $U$ among Co 3$d$ electrons within the LDA+$U$ method leads to a better representation of experimental results. Signature of electron correlation induced satellite feature is also observed in the Co 2$p$ core level spectrum. These results clearly demonstrate the importance of the electron correlation among conduction electrons in deriving the microscopic description of such Kondo systems.Comment: 6 figure

Endophytic Mycoflora of Indian Medicinal Plant, Terminalia arjuna and their Biological Activities

Studies were undertaken to isolate, identify and evaluate the biological activities of endophytic mycoflora of Indian medicinal plant, Terminalia arjuna. A total of 20 isolates of endophytic fungi were obtained from the leaves, twigs and bark tissues of the Terminalia arjuna. Out of 20, six isolates exhibited promising antibacterial, antifungal and anti-inflammatory activities when cultivated at shake flask level. The selected isolates were identified on the basis of morphology and ITS gene sequencing. Three isolates, designated as TA BA 1, TA L1 and TA L2 were identified as Aspergillus flavus whereas; the remaining three endophytic fungi were identified as Diaporthe arengae (TA TW2), Alternaria Sp. (TA TW1) and Lasiodiplodia theobromae (TA BA2). Aspergillus flavus was found as the predominant endophyte in leaves and bark tissues of the plant. The crude extract of the test isolates showed considerable antimicrobial activity against common human bacterial (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Salmonella abony and Bacillus subtilis) and fungal (Candida albicans, Aspergillus niger and Penicilium sp.) pathogens. The extract of Diaporthe arengae (TA TW2) significantly reduced the concentration of DPPH free radical as percent DPPH scavenging activity was found to be highest (69.56%) in comparison with other isolates. The % inhibition of hemolysis of RBCs was found to be highest (82.85%) with Diaporthe arengae (TA TW2) in comparison (83.26%) with standard drug (Ibuprofen). Among all, the extract of the Diaporthe arengae (TA TW2) showed excellent biological activities and hence was subjected to further characterization. The phytochemical investigation of the extract revealed the presence of terpenoids as the major phytoconstituents which was supported by TLC and UV spectroscopic studies. The results indicate that the isolated endophytes could be the valuable source of these bioactive molecules with diverse biological activities. The bioactivities may be attributed to the terpenoids present in the endophytic extract

Evolution of the Kondo resonance feature and its relationship to spin-orbit coupling across the quantum critical point in Ce2Rh{1-x}CoxSi3

We investigate the evolution of the electronic structure of Ce2Rh{1-x}CoxSi3 as a function of x employing high resolution photoemission spectroscopy. Co substitution at the Rh sites in antiferromagnetic Ce2RhSi3 leads to a transition from an antiferromagnetic system to a Kondo system, Ce2CoSi3 via the Quantum Critical Point (QCP). High resolution photoemission spectra reveal distinct signature of the Kondo resonance feature (KRF) and its spin orbit split component (SOC) in the whole composition range indicating finite Kondo temperature scale at the quantum critical point. We observe that the intensity ratio of the Kondo resonance feature and its spin orbit split component, KRF/SOC gradually increases with the decrease in temperature in the strong hybridization limit. The scenario gets reversed if the Kondo temperature becomes lower than the magnetic ordering temperature. While finite Kondo temperature within the magnetically ordered phase indicates applicability of the spin density wave picture at the approach to QCP, the dominant temperature dependence of the spin-orbit coupled feature suggests importance of spin-orbit interactions in this regime.Comment: 6 figure

A retrospective study to evaluate the pattern of spontaneously reported antiretroviral induced adverse drug reactions in a tertiary care hospital

Background: To evaluate the adverse effect profile of spontaneously reported cases of adverse drug reactions due to antiretroviral (ART) drugs in a tertiary care teaching hospital.Methods: A descriptive retrospective study of pattern of ART induced adverse drug reactions (ADRs) spontaneously reported to the Pharmacology department at a tertiary care hospital from January 2011 to December 2016. The details of suspected ADRs including drugs involved, treatment given for ADRs, and the outcome were also documented. These ADRs were analyzed for causality (WHO scale), severity (Hartwig et al. scale), seriousness (ICH E 2A guidelines), preventability (Schumock and Thornton scale) and type based on Edwards and Aronson classification system.Results: Of the 75 cases of ART induced ADRs, reactions were slightly more common in males (52%) and had median age and duration of ART as 36 years and 109 days respectively. Drug induced anemia was the most common presentation followed by cutaneous ADR and zidovudine being the commonest offender. Severity was moderate in 85.3% and causality was probable in 16% and possible in 84% cases. The type reaction was augmented type in 41.3% and not preventable in 76%.Conclusions: Zidovudine is the commonest drug implicated in causing anemia amongst the antiretrovirals. Spontaneous reporting method for antiretroviral pharmacovigilance is insufficient. Targeted spontaneous reporting or cohort event monitoring need to be studied for antiretroviral pharmacovigilance

Fixed drug eruptions to ciprofloxacin - a case report

Fixed drug eruptions (FDE) are common adverse drug reactions and they recur at the same site with each exposure to a particular drug. Drugs inducing FDE are usually those taken intermittently. Most common drugs causing fixed drug eruptions are antibiotics and analgesics. Here, we report a case of FDE to ciprofloxacin which was used in treatment of upper respiratory tract infection

Bacterial and clinical profile of diabetic foot ulcer using optimal culture techniques

Background: Diabetic foot ulcers (DFU) are the complications of diabetes mellitus. The diabetic foot ulcer infections are polymicrobial in nature. If they are not recognized and controlled it leads to many devastating consequences like limb amputation, sepsis, and even mortality. Hence, the present study was undertaken to determine the bacterial and clinical profile of diabetic foot ulcer using optimal culture techniques and the antimicrobial sensitivity pattern of the isolates.Methods: A total number of 103 patients with a foot ulcer of Wagner’s grade II or more and evidence of purulent exudates or edema were included in the study. Swab samples were obtained from the base of ulcers and were sent for bacteriological study. The specimen was processed in the microbiology laboratory for Gram stain, aerobic culture, and anaerobic culture. The organisms isolated were identified by standard procedures and antimicrobial susceptibility was done by Kirby-Bauer disc diffusion method.Results: A total no of 253 organisms were isolated from 103 patients. Out of these, 217 aerobes were isolated, and the most common organism isolated from gram positive bacteria was Staphylococcus aureus, 53 (24.42 %). Pseudomonas aeruginosa, 42 (19.35 %) was the predominant organism isolated from gram negative bacteria. Among the total 36 anaerobes, Bacteroides fragilis group, 17 (47.22 %) was the most common organism isolated. All the gram positive aerobic organisms were found to be sensitive for vancomycin. Among the gram negative organisms, E. coli, Proteus mirabilis, Proteus vulgaris, showed more sensitivity to cefotaxime (90.62%, 91.66%, 75%) respectively. Metronidazole was the drug of choice in case of anaerobes followed by imipenem.Conclusions: It is necessary to identify the etiological factors and susceptible microorganisms responsible for causation of DFU. So that prompt management of diabetic foot ulcers is possible for successful outcome. Appreciation of the causative organisms in diabetic foot and their antibiotic sensitivity is essential for institution of appropriate antibiotic therapy