Effect of size and dimensionality on the magnetic moment of transition metals

The effect of size and dimensionality on the magnetic moments of Fe, Co, and Ni have been studied theoretically by confining the atoms to various structural forms such as chains, surfaces, and thin films. The size of these systems is controlled by limiting the number of atoms. A new first‐principles theory is developed that enables us to study the electron spin density of states and moments of atoms in clusters containing two to a few thousand atoms. The theory is based upon the elementary principles governing the tight binding and linear combination of atomic orbitals formulations. It contains no adjustable parameters and can be applied to systems with or without topological symmetry. We have discovered quantum size effects on the magnetic moments of linear chains and these effects disappear when the chains contain more than 20 atoms. We have also found distinct effects of the local environment on the magnetic moment. For example, the moments increase with decreasing coordination number and increasing interatomic distance. Our results will be compared with available experimental and theoretical results

Acupuncture randomized trials (ART) in patients with chronic low back pain and osteoarthritis of the knee - Design and protocols

Background: We report on the study design and protocols of two randomized controlled trials (Acupuncture Randomized Trials = ART) that investigate the efficacy of acupuncture in the treatment of chronic low back pain and osteoarthritis of the knee, respectively. Objective: To investigate whether acupuncture is more efficacious than (a) no treatment or (b) minimal acupuncture in the treatment of low back pain and osteoarthritis. Design: Two randomized, controlled, multicenter trials with three treatment arms and a total follow-up time of 52 weeks. Setting: 30 practitioners and outpatient units in Germany specialized in acupuncture treatment. Patients: 300 patients will be included in each study. In the low back pain trial, patients will be included according to clinical diagnosis. In the osteoarthritis pain trial, patients will be included according to the American College of Rheumatology criteria. Interventions: Patients are randomly assigned to receive either (1) semi-standardized acupuncture (150 patients), (2) minimal acupuncture at non-acupuncture points (75 patients), or (3) no treatment for two months followed by semi-standardized acupuncture (75 patients, waiting list control). Acupuncture treatment consists of 12 sessions per patient over a period of 8 weeks. Main Outcome Measure: The main outcome measure is the difference between baseline and the end of the 8-week treatment period in the following parameters: pain intensity as measured by a visual analogue scale (VAS; 0-100 mm) in the low back pain trial and by the Western Ontario and McMaster Universities Osteoarthritis Score (WOMAC) in the osteoarthritis trial. Outlook: The results of these two studies (available in 2004) will provide health care providers and policy makers with the information needed to make scientifically sound assessments of acupuncture therapy

Adherence to deferasirox among beta-thalassemia major children - A cross-sectional study in a tertiary care hospital

Introduction: Deferasirox, an oral iron chelator has been proved to be very safe and effective in beta-thalassemia major children on chronic blood transfusion (CBT); however, adherence to this medication has always been a challenge. Objectives: The aim of this study is to assess the adherence to oral iron chelator- deferasirox among beta-thalassemia major children receiving CBT by using selfreporting questionnaire and the factors associated with poor adherence to deferasirox. Materials and Methods: A cross- sectional study was conducted enrolling 91 beta-thalassemia major children (aged between 2 and 14 years, transfused with at least 20 units of packed red blood cell, on deferasirox therapy and serum ferritin greater than 1000 ng/ml) by simple consecutive sampling. Pretested interview schedule was used to collect information on sociodemographic status. Morisky Medication Adherence Scale was used to measure adherence. Data were entered in Microsoft Excel student 2017 and analyzed using SPSS software version 24. Results: About 7.5% (7) of the patients reported to be highly adherent, 48.4% (45) moderately, and 41.9% (39) were poorly adherent. The mean (SD) serum ferritin value was lowest (1281.71±326.85 ng/ml) in highly adherent children. Association betweenthe age and serum ferritin with adherence to deferasirox done using one-way ANOVA was found to be statistically significant among the three different groups (p=0.000). Illiteracy negatively affected the degree of adherence, while belonging to a nuclear family positively affected the degree of adherence to deferasirox. Conclusion: A very low-adherence level was observed in this study which needs to be improved through adequate measures

Geometry, electronic structure, and energetics of copper-doped aluminum clusters

Using density functional theory and generalized gradient approximation for exchange-correlation potential, we have calculated the equilibrium geometries and energetics of neutral and negatively charged AlnCu (n=11,12,13,14) clusters. Unlike the alkali atom-doped aluminum clusters in the same size range, the copper atom resides inside the aluminum cluster cage. Furthermore, the 3d and 4s energy levels of Cu hybridize with the valence electrons of Al causing a redistribution of the molecular orbital energy levels of the Aln clusters. However, this redistribution does not affect the magic numbers of AlnCu clusters that could be derived by assuming that Cu donates one electron to the valence levels of Aln clusters. This behavior, brought about by the smaller size and large ionization potential of the copper atom, contributes to the anomalous properties of AlnCu− anions: Unlike AlnX− (X=alkali atom), the mass ion intensities of AlnCu− are similar to those of Al−n. The calculated adiabatic electron affinities are also in very good agreement with experiment

Electronic structure and chemical bonding of 3d-metal dimers ScX, X=Sc-Zn

The electronic and geometrical structures of the ground and excited states of the homonuclear Sc2, mixed ScTi, ScV, ScCr, ScMn, ScFe, ScCo, ScNi, ScCu, and ScZn 3d-metal dimers and their anions have been calculated using the density functional theory with generalized gradient approximation for the exchange-correlation potential. The ground states of the neutral dimers are found to be 5Σ−u (Sc2), 6Σ+ (ScTi), 7Σ+ (ScV), 4Σ+ (ScCr), 3Σ+ (ScMn), 2Δ(ScFe), 1Σ+ (ScCo), 2Σ+ (ScNi), 3Δ(ScCu), and 4Σ+ (ScZn). A natural bond analysis reveals an antiferrimagnetic spin coupling in the ground states of ScCr, ScMn, and ScFe. This is due to the electron transfer from Sc to the opposite atom and specific bond formations. While each dimer has a unique chemical bonding pattern, most curious is the localization of two 4s electrons at both atomic sites in the ground 5Σ−u state of Sc2, which leads to formation of two lone pairs and the bonding scheme: (3d+3d)3α(4s+4s)1β. No appreciable sd hybridization is found for the ground states of the ScX dimers except for ScNi. Even though the electron affinities of the ScX dimers are relatively low and do not exceed 1 eV, each ScX− (except ScCo−) possesses at least two states stable towards detachment of an extra electron