1,154 research outputs found
Possible signatures of mixed-parity superconductivity in doped polar SrTiO3 films
Superconductors that possess both broken spatial inversion symmetry and
spin-orbit interactions exhibit a mix of spin singlet and triplet pairing.
Here, we report on measurements of the superconducting properties of
electron-doped, strained SrTiO3 films. These films have an enhanced
superconducting transition temperature and were previously shown to undergo a
transition to a polar phase prior to becoming superconducting. We show that
some films show signatures of an unusual superconducting state, such as an
in-plane critical field that is higher than both the paramagnetic and orbital
pair breaking limits. Moreover, nonreciprocal transport, which reflects the
ratio of odd versus even pairing interactions, is observed. Together, these
characteristics indicate that these films provide a tunable platform for
investigations of unconventional superconductivity
A Hierarchical Approach to Protein Molecular Evolution
Biological diversity has evolved despite the essentially infinite complexity
of protein sequence space. We present a hierarchical approach to the efficient
searching of this space and quantify the evolutionary potential of our approach
with Monte Carlo simulations. These simulations demonstrate that non-homologous
juxtaposition of encoded structure is the rate-limiting step in the production
of new tertiary protein folds. Non-homologous ``swapping'' of low energy
secondary structures increased the binding constant of a simulated protein by
relative to base substitution alone. Applications of our approach
include the generation of new protein folds and modeling the molecular
evolution of disease.Comment: 15 pages. 2 figures. LaTeX styl
Alcohols increase calmodulin affinity for Ca2+ and decrease target affinity for calmodulin
AbstractIt has been proposed that alcohols and anesthetics selectively inhibit proteins containing easily disrupted motifs, e.g., α-helices. In this study, the calcineurin/calmodulin/Ca2+ enzyme system was used to examine the effects of alcohols on calmodulin, a protein with a predominantly α-helical structure. Calcineurin phosphatase activity and Ca2+ binding were monitored as indicators of calmodulin function. Alcohols inhibited enzyme activity in a concentration-dependent manner, with two-, four- and five-carbon n-alcohols exhibiting similar leftward shifts in the inhibition curves for calmodulin-dependent and -independent activities; the former was slightly more sensitive than the latter. Ca2+ binding was measured by flow dialysis as a direct measure of calmodulin function, whereas, with the addition of a binding domain peptide, measured calmodulin–target interactions. Ethanol increased the affinity of calmodulin for Ca2+ in the presence and absence of the peptide, indicating that ethanol stabilizes the Ca2+ bound form of calmodulin. An increase in Ca2+ affinity was detected in a calmodulin binding assay, but the affinity of calmodulin for calcineurin decreased at saturating Ca2+. These data demonstrate that although specific regions within proteins may be more sensitive to alcohols and anesthetics, the presence of α-helices is unlikely to be a reliable indicator of alcohol or anesthetic potency
Decreased Vision and Junctional Scotoma from Pituicytoma
Pituicytomas are rare neoplasms of the sellar region. We report a case of vision loss and a junctional scotoma in a 43-year-old woman caused by compression of the optic chiasm by a pituitary tumor. The morphological and immunohistochemical characteristics of the tumor were consistent with the diagnosis of pituicytoma. The tumor was debulked surgically, and the patient's vision improved
Detection of Candida species in vaginal samples in a clinical laboratory setting.
OBJECTIVE: To present the detection rates of Candida species in vaginal samples from patients visiting physicians. METHODS: The presence of C. albicans, C. glabrata, C. parapsilosis and C. tropicalis in 3978 vaginal swabs from patients in six US states was detected by PCR amplification. RESULTS: Candida DNA was detected in 33.1% of the population studied. Of the 1316 positive samples, 80.2% contained C. albicans, 14.3% contained C. glabrata, 5.9% contained C. parapsilosis and 8.0% contained C. tropicalis. Comparing samples by patients' state of residence revealed an association with the detection of C. glabrata (p = 0.029). Comparing samples by patients' age revealed a decrease in the overall detection of Candida (p < 0.001) and C. albicans (p < 0.001), concomitant with an increase in the detection of C. glabrata (p < 0.001) and C. parapsilosis (p = 0.025). CONCLUSIONS: These results provide geographic- and age-specific data on four Candida species associated with vaginitis
Автоматическая синхронизация генераторов
Исследование методов синхронизации генератора, в частности, точная синхронизация и самосинхронизация. В работе проводилось исследование определения оптимальных параметров включения генератора на параллельную работу. Проверялось влияние основных параметров, подключаемого к сети генератора, на возникновение ударных токов.Investigation of synchronization methods of the generator, in particular, precise synchronization and self-synchronization.In work the research of definition of optimum parameters of generator inclusion on parallel work was carried out. The effect of the main parameters connected to the generator network on the occurrence of shock currents was checked
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