A study of the T2 defect and the emission properties of the E3 deep level in annealed melt grown ZnO single crystals

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Effect of exercise on cardiac autonomic function in females with rheumatoid arthritis

The objective of this study is to evaluate the effect of exercise on cardiac autonomic function as measured by short-term heart rate variability (HRV) in females suffering from rheumatoid arthritis (RA). Females with confirmed RA were randomly assigned to an exercise group (RAE) and a sedentary group (RAC). RAE was required to train under supervision two to three times per week, for 3 months. Three techniques (time domain, frequency domain and Poincaré plot analyses) were used to measure HRV at baseline and study completion. At baseline, RAC (n018) had a significantly higher variability compared to RAE (n019) for most HRV indicators. At study completion, the variables showing significant changes (p00.01 to 0.05) favoured RAE in all instances. Wilcoxon signed rank tests were performed to assess changes within groups from start to end. RAE showed significant improvement for most of the standing variables, including measurements of combined autonomic influence, e.g. SDRR (p00.002) and variables indicating only vagal influence, e.g. pNN50 (p00.014). RAC mostly deteriorated with emphasis on variables measuring vagal influence (RMSSD, pNN50, SD1 and HF (ms2)). Study results indicated that 12 weeks of exercise intervention had a positive effect on cardiac autonomic function as measured by short-term HRV, in females with RA. Several of the standing variables indicated improved vagal influence on the heart rate. Exercise can thus potentially be used as an instrument to improve cardiac health in a patient group known for increased cardiac morbidity.http://www.springerlink.com/content/102818

Knotted vs. Unknotted Proteins: Evidence of Knot-Promoting Loops

Knotted proteins, because of their ability to fold reversibly in the same topologically entangled conformation, are the object of an increasing number of experimental and theoretical studies. The aim of the present investigation is to assess, on the basis of presently available structural data, the extent to which knotted proteins are isolated instances in sequence or structure space, and to use comparative schemes to understand whether specific protein segments can be associated to the occurrence of a knot in the native state. A significant sequence homology is found among a sizeable group of knotted and unknotted proteins. In this family, knotted members occupy a primary sub-branch of the phylogenetic tree and differ from unknotted ones only by additional loop segments. These "knot-promoting" loops, whose virtual bridging eliminates the knot, are found in various types of knotted proteins. Valuable insight into how knots form, or are encoded, in proteins could be obtained by targeting these regions in future computational studies or excision experiments

The Effect Of Stress On Antioxidative Potential Of Serum

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Electrical characterization of defects in heavy-ion implanted n-type Ge

Deep-level transient spectroscopy was used to investigate the electrically active defects introduced in n-type Ge during heavy-ion implantation of 160 keV ions. Various noble heavy-ions were used for implantation and the main defects introduced were found to be electron traps with energy levels at E-C - 0.09 eV, E-C - 0.15 eV and E-C - 0.30 eV. Another defect with a level at E-C - 0.38 eV, shown to be the E-center (V-Sb defect), is also present in a very low concentration. The main defects in heavy-ion implanted Ge are different from those introduced by MeV electron irradiation, where the main defect is the E-center. Since electron irradiation introduces mainly point defects, this indicates that heavy-ion implantation introduces defects of a more extended nature, such as vacancy and/or interstitial clusters and their combinations with impurities or foreign species in the Ge. We have also demonstrated that these defects are not species related. (C) 2007 Elsevier B.V. All rights reserved.status: publishe