1,837 research outputs found
Electronic states of PrCoO: X-ray photoemission spectroscopy and LDA+U density of states studies
Electronic states of PrCoO are studied using x-ray photoemission
spectroscopy. Pr 3d core level and valence band (VB) were recorded
using Mg K source. The core level spectrum shows that the 3d
level is split into two components of multiplicity 4 and 2, respectively due to
coupling of the spin states of the hole in 3d with Pr 4f holes spin
state. The observed splitting is 4.5 eV. The VB spectrum is interpreted using
density of states (DOS) calculations under LDA and LDA+U. It is noted that LDA
is not sufficient to explain the observed VB spectrum. Inclusion of on-site
Coulomb correlation for Co 3d electrons in LDA+U calculations gives DOS which
is useful in qualitative explanation of the ground state. However, it is
necessary to include interactions between Pr 4f electrons to get better
agreement with experimental VB spectrum. It is seen that the VB consists of Pr
4f, Co 3d and O 2p states. Pr 4f, Co 3d and O 2p bands are highly mixed
indicating strong hybridization of these three states. The band near the Fermi
level has about equal contributions from Pr 4f and O 2p states with somewhat
smaller contribution from Co 3d states. Thus in the Zaanen, Sawatzky, and Allen
scheme PrCoO can be considered as charge transfer insulator. The charge
transfer energy can be obtained using LDA DOS calculations and the
Coulomb-exchange energy U' from LDA+U. The explicit values for PrCoO are
= 3.9 eV and U' = 5.5 eV; the crystal field splitting and 3d bandwidth
of Co ions are also found to be 2.8 and 1.8 eV, respectively.Comment: 12 pages, 7 figures; to appear J. Phys.: Condens. Matte
Highly active supported palladium catalyst for the regioselective synthesis of 2-arylpropionic acids by carbonylation
This is the published version. Copyright © Royal Society of Chemistry 1999A catalyst system consisting of supported palladium in the presence of phosphine ligands, TsOH and LiCl catalyses the carbonylation of 1-arylethanols to 2-arylpropionic acids with significantly improved activity and regioselectivity; the catalyst can be recycled with no loss in activity and selecivity
Ex-HABE with User Accountability for Secure Access Control in Cloud
Data outsourcing is becoming a useful and feasible paradigm with the rapid application of service-oriented technologies. Many researchers have tried combination of access control and cryptography to propose a model to protect sensitive information in this outsourcing scenario. However, these combinations in existing approaches have difficulty in key management and key distribution when fine-grained data access is required. Taking the complexity of fine-grained access control policy and the wide-reaching users of cloud in account, this issue would become extremely difficult to iron out. Various system models using attribute-based encryption (ABE) have been proposed however, most of them suffer from heavy overhead in implementing the access control policies. In this paper, a system is proposed with extended hierarchical attribute-based encryption (HABE) by using ciphertext-policy attribute-based encryption (ABE). It uses the hierarchical structure of users and bilinear mapping for generating the keys for various data handlers. Also the system focuses on user tracking by allocating an unique id to user. The system uses traitor tracing along with separation of duty made available by HABE and reduces the scope of key abuse. It is formally proved extended HABE with traitor tracing adds on to user accountability if user tracking for resource is maintained for hierarchical systems.
DOI: 10.17762/ijritcc2321-8169.16042
Highly active water-soluble palladium catalyst for the regioselective carbonylation of vinyl aromatics to 2-arylpropionic acids
This is the published version. Copyright © The Royal Society of Chemistry 2000A novel water-soluble Pd complex containing pyridine carboxylate and TPPTS as ligands is a highly active catalyst for the carbonylation of vinyl aromatics under biphasic conditions and provides high regioselectivity to 2-arylpropionic acids
Cognitive functions in first degree normative relative of patients with schozophrenia
Background: Schizophrenia is severe disorders and imposes a considerable burden on patients, their families and society. Schizophrenia tends to run in family, like most mental disorder shows complex inheritance. Therefore, it is important to increase our knowledge about the disorder. Cognitive dysfunction is one of the core features of Schizophrenia. This study aims to compare the cognitive function of first degree unaffected relative of patient of schizophrenia and a group of healthy control.Methods: The study include 48 first degree normative relative of patient with Schizophrenia and 48 controls. Compared for age, sex, education level. Cognitive functions of each case and control were assessed using TMT (Trail making Test), Paced auditory serial addition Test (PASAT) and Wisconsin card sorting test (WCST-64).Results: First degree relative performed significantly poorly as compared to controls on Wisconsin card sorting Test-64 (WCST-64). No significant difference was observed in tests performances between first degree relative of Schizophrenia and control group for TMT (trail making test) and Paced auditory serial addition Test (PASAT).Conclusions: The study shows possibility of cognitive impairment in first degree normative relative of Schizophrenia with regards to parameters like poor performance in shifting cognitive sets and poor understanding of test. Nevertheless, it is not clear weather this finding is an enduring trait mark or finding that fluctuates with sample size, nature of case and control
INJURY INCIDENCE, DISTRIBUTION, AND SEVERITY DURING A MARATHON TRAINING SEASON AND THE IMPLICATIONS
Marathon runners and their coaches are concerned about the potential for injury during an individual season. No published studies of running injuries address this training season as a meaningful entity. This study reports the incidence of injury and the distribution of injuries for runners (n=75) on two established marathon training teams during an individual season. An injury was defined as affecting seven consecutive days or three consecutive workouts. The incidence/risks of overuse injuries, for marathon runners in a single season were found to be: anterior knee pain (20%), iliotibial band syndrome (29%), plantar fasciitis (1%), Achilles tendonitis (9%) shin splints (16%) and stress fractures (4%). This risk, overall injury distribution, severity and length of longest run prior to presentation of injury are of interest to runners, coaches and biomechanists
DEVELOPMENT OF A DENSITOMETRIC HIGH-PERFORMANCE THIN-LAYER CHROMATOGRAPHIC METHOD FOR THE QUANTITATIVE ANALYSIS OF URSOLIC ACID IN THE LEAVES OF SPECIES OF GENUS TECOMA AND TABEBUIA OF BIGNONIACEAE FAMILY
Objective: A simple and sensitive high-performance thin–layer chromatographic (HPTLC) method was developed for the quantification of ursolic acid in the leaves of three species of genus Tecoma (Tecoma gaudichaudi DC, Tecoma capensis (Thunb.) Lindl, Tecoma stans (L.) Juss. ex Kunth) and genus Tabebuia (Tabebuia rosea Bertol) belong to family Bignoniaceae.Methods: Chromatography was performed on Silica gel 60 F254 precoated HPTLC Plates with optimised mobile phase pet ether: ethyl acetate: formic acid (7:3:0.5, v/v/v). The plate was derivatized with p-anisaldehyde reagent and scanned at 540 nm. The developed method was found to give a compact spot for ursolic acid at Rf value 0.43±0.01. The method was validated using International Council for Harmonization (ICH) guidelines, including linearity, precision, accuracy, and robustness.Results: Ursolic acid was found to be present in four species, i.e., Tecoma gaudichaudi DC (1.48%w/w), Tecoma capensis (Thunb.) Lindl. (0.79%w/w), Tecoma stans (L.) Juss. Ex Kunth (1.11%w/w), Tabebuia rosea (Bertol.) (1.13%w/w). A good linearity relationship was found to be (200-1400ng band−1) with a correlation coefficient (r2) value of 0.9946 with ursolic acid. Limit of detection and limit of quantification was considered to be 40.66, 123.21 ng per band respectively. The developed method was found to be accurate and precise with 1.32%, 1.19% (%RSD) for interday and intraday precision. The accuracy of the method was performed by recovery studies at three different concentration levels, and the average percentage recovery was found to be 98.05% for ursolic acid.Conclusion: The proposed method for the quantitation of ursolic acid was found to be reproducible and simple
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