670 research outputs found
Early resistance change and stress/electromigration evolution in near bamboo interconnects
A complete description for early resistance change and mechanical stress evolution in near-bamboo interconnects, related to the electromigration, is given in this paper. The proposed model, for the first time, combines the stress/vacancy concentration evolution with the early resistance change of the Al line with a near-bamboo microstructure, which has been proven to be a fast technique for prediction of the MTF of a line compared to the conventional (accelerated) stres
Analysis of Binding Site Hot Spots on the Surface of Ras GTPase
We have recently discovered an allosteric switch in Ras, bringing an additional level of complexity to this GTPase whose mutants are involved in nearly 30% of cancers. Upon activation of the allosteric switch, there is a shift in helix 3/loop 7 associated with a disorder to order transition in the active site. Here, we use a combination of multiple solvent crystal structures and computational solvent mapping (FTMap) to determine binding site hot spots in the “off” and “on” allosteric states of the GTP-bound form of H-Ras. Thirteen sites are revealed, expanding possible target sites for ligand binding well beyond the active site. Comparison of FTMaps for the H and K isoforms reveals essentially identical hot spots. Furthermore, using NMR measurements of spin relaxation, we determined that K-Ras exhibits global conformational dynamics very similar to those we previously reported for H-Ras. We thus hypothesize that the global conformational rearrangement serves as a mechanism for allosteric coupling between the effector interface and remote hot spots in all Ras isoforms. At least with respect to the binding sites involving the G domain, H-Ras is an excellent model for K-Ras and probably N-Ras as well. Ras has so far been elusive as a target for drug design. The present work identifies various unexplored hot spots throughout the entire surface of Ras, extending the focus from the disordered active site to well-ordered locations that should be easier to target
Identification of health needs and problems of Black employees in the Germiston City Health Department
The aim of this study was to identify the health needs and problems of black
employees within the Germiston City Health Department in order to indicate a
possible relationship between such needs and problems and a high rate of
absenteeism.
Although the findings could relate to all employees, this study was limited to
black employees only. Data was collected by means of observation, perusal of
health records and personal interviews with personnel as well as with the
selected sample. The results of the study highlighted the specific health needs
and problems of employees as well as factors which could influence their health
status and which could contribute to the problem of absenteeism. The main
factors identified included interalia poor working conditions and unsatisfactory
methods of solving employees problems. Relevant recommendations were made ;·
to address the problem of absenteeism in the Germiston City Health DepartmentHealth StudiesM.A. (Nursing Science
Liquid heat capacity in the approach from the solid state: anharmonic theory
Calculating liquid energy and heat capacity in general form is an open
problem in condensed matter physics. We develop a recent approach to liquids
from the solid state by accounting for the contribution of anharmonicity and
thermal expansion to liquid energy and heat capacity. We subsequently compare
theoretical predictions to the experiments results of 5 commonly discussed
liquids, and find a good agreement with no free fitting parameters. We discuss
and compare the proposed theory to previous approaches.Comment: 8 pages, 6 figure
Quantum localization in rough billiards
We study the level spacing statistics p(s) and eigenfunction properties in a
billiard with a rough boundary. Quantum effects lead to localization of
classical diffusion in the angular momentum space and the Shnirelman peak in
p(s) at small s. The ergodic regime with Wigner-Dyson statistics is identified
as a function of roughness. Applications for the Q-spoiling in optical
resonators are also discussed.Comment: revtex, 4 pages, 5 figure
- …