1,215 research outputs found
Significant enhancement of irreversibility field in clean-limit bulk MgB2
Low resistivity ("clean") MgB2 bulk samples annealed in Mg vapor show an
increase in upper critical field Hc2(T) and irreversibility field Hirr(T) by a
factor of 2 in both transport and magnetic measurements. The best sample
displayed Hirr above 14 T at 4.2 K and 6 T at 20 K. These changes were
accompanied by an increase of the 40 K resistivity from 1.0 to 18 microohm-cm
and a lowering of the resistivity ratio from 15 to 3, while the critical
temperature Tc decreased by only 1-2 K. These results point the way to make
prepare MgB2 attractive for magnet applications.Comment: 3 pages, 4 figures, submitted to Applied Physics Letter
Cu_{2}O as nonmagnetic semiconductor for spin transport in crystalline oxide electronics
We probe spin transport in Cu_{2}O by measuring spin valve effect in
La_{0.7}Sr_{0.3}MnO_{3}/Cu_{2}O/Co and
La_{0.7}Sr_{0.3}MnO_{3}/Cu_{2}O/La_{0.7}Sr_{0.3}MnO_{3} epitaxial
heterostructures. In La_{0.7}Sr_{0.3}MnO_{3}/Cu_{2}O/Co systems we find that a
fraction of out-of-equilibrium spin polarized carrier actually travel across
the Cu_{2}O layer up to distances of almost 100 nm at low temperature. The
corresponding spin diffusion length dspin is estimated around 40 nm.
Furthermore, we find that the insertion of a SrTiO_{3} tunneling barrier does
not improve spin injection, likely due to the matching of resistances at the
interfaces. Our result on dspin may be likely improved, both in terms of
Cu_{2}O crystalline quality and sub-micrometric morphology and in terms of
device geometry, indicating that Cu_{2}O is a potential material for efficient
spin transport in devices based on crystalline oxides.Comment: 15 pages, 10 figure
Critical Field of MGB2 : Crossover from Clean to Dirty Regimes
We have studied the upper critical field, Bc2, in poly-crystalline MgB2
samples in which disorder was varied in a controlled way to carry selectively p
and s bands from clean to dirty limit. We have found that the clean regime
survives when p bands are dirty and s bands are midway between clean and dirty.
In this framework we can explain the anomalous behaviour of Al doped samples,
in which Bc2 decreases as doping increases.Comment: 11 pages, 2 figure
Sex-Specific Impacts of Exercise on Cardiovascular Remodeling
Cardiovascular diseases (CVD) remain the leading cause of death in men and women. Biological sex plays a major role in cardiovascular physiology and pathological cardiovascular remodeling. Traditionally, pathological remodeling of cardiovascular system refers to the molecular, cellular, and morphological changes that result from insults, such as myocardial infarction or hypertension. Regular exercise training is known to induce physiological cardiovascular remodeling and beneficial functional adaptation of the cardiovascular apparatus. However, impact of exercise-induced cardiovascular remodeling and functional adaptation varies between males and females. This review aims to compare and contrast sex-specific manifestations of exercise-induced cardiovascular remodeling and functional adaptation. Specifically, we review (1) sex disparities in cardiovascular function, (2) influence of biological sex on exercise-induced cardiovascular remodeling and functional adaptation, and (3) sex-specific impacts of various types, intensities, and durations of exercise training on cardiovascular apparatus. The review highlights both animal and human studies in order to give an all-encompassing view of the exercise-induced sex differences in cardiovascular system and addresses the gaps in knowledge in the field
Association between the multidimensional prognostic index and mortality during 15 Years of Follow-up in the InCHIANTI Study
Background: Multidimensional Prognostic Index (MPI) is recognized as a prognostic tool in hospitalized patients, but data on the value of MPI in community-dwelling older persons are limited. Using data from a representative cohort of community-dwelling persons, we tested the hypothesis that MPI explains mortality during 15 years of follow-up. Methods: A standardized comprehensive geriatric assessment was used to calculate the MPI and to categorize participants in low-, moderate-, and high-risk classes. The results were reported as hazard ratios (HRs) and the accuracy was evaluated with the area under the curve (AUC), with 95% confidence intervals (CIs) and the C-index. We also reported the median survival time by standard age groups. Results: All 1453 participants (mean age 68.9 years, women = 55.8%) enrolled in the InCHIANTI study at baseline were included. Compared to low-risk group, participants in moderate (HR = 2.10; 95% CI: 1.73-2.55) and high-risk MPI group (HR = 4.94; 95% CI: 3.91-6.24) had significantly higher mortality risk. The C-index of the model containing age, sex, and MPI was 82.1, indicating a very good accuracy of this model in explaining mortality. Additionally, the time-dependent AUC indicated that the accuracy of the model incorporating MPI to age and sex was excellent (>85.0) during the whole follow-up period. Compared to participants in the low-risk MPI group across different age groups, those in moderate- and high-risk groups survived 2.9-7.0 years less and 4.3-8.9 years less, respectively. Conclusions: In community-dwelling individuals, higher MPI values are associated with higher risk of all-cause mortality with a dose-response effect. © 2020 The Author(s) 2020
Enhanced flux pinning in neutron irradiated MgB2
We study the effect of neutron irradiation on the critical current density Jc
of isotopically pure polycrystalline Mg11B2 samples. For fluences in the range
1017-1018 cm-2, Jc is enhanced and its dependence on magnetic field is
significantly improved: we demonstrate that, in this regime, point-like pinning
centers are effectively introduced in the system proportionally to the neutron
fluence. Instead, for larger fluences, a strong suppression of the critical
temperature accompanied by a decrease of both the upper critical field Bc2 and
Jc is found.Comment: 13 pages, 3 igure
Effects of acculturation, coping strategies, locus of control, and self-efficacy on chronic pain: Study of Chinese immigrant women in Italy - insights from a thematic field analysis
Chronic pain represents a common public health concern worldwide. It is a complex phenomenon, owing to the interaction of different factors, including biological, physiological, psychological, environmental, and social variables. Some groups, such as women and immigrants, are particularly vulnerable. However, little is known about how Chinese women in Italy live with and face chronic pain. The present study aimed at filling this knowledge gap by examining the burden of chronic pain in Chinese immigrants in Italy in terms of acculturation processes, perceived control over disease, social networks, and coping strategies. A qualitative approach was used, performing a thematic field analysis. We interviewed 82 Chinese women from different Italian towns (Genoa, Milan, Turin, Bologna, Florence, and Prato) in depth. The sense of belonging to the host culture was strong in our sample. However, this did not simply reflect or translate into a linear engagement with medical systems, as health care pathways were more complex and dual (both Chinese and Western). Chinese women who felt deeply rooted in the Italian environment did not discontinue the use of traditional Chinese medicine. Chronic pain extensively and adversely affected daily life, particularly interfering with work. Coping strategies were mainly adaptive behaviors, being problem focused or maladaptive, relying upon “cope and avoid” mechanisms. Chinese women preferred to use traditional Chinese remedies rather than conventional medicine, while using the Italian system in emergencies. Perceived control over chronic pain was usually external. Finally, Chinese women with chronic pain benefit from social networks and support, which were mainly composed of Chinese peers. In conclusion, our findings underline the tremendous burden of chronic pain affecting all aspects of Chinese women’s lives. Health care workers and providers should be aware of the complexity of chronic pain Therefore, a holistic approach, involving different stakeholders, should be adopted when managing chronic pain and approaching immigrant patients
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