1,133 research outputs found
Accurate calculation of the interaction of a barium monofluoride molecule with an argon atom: A step towards using matrix isolation of BaF for determining the electron electric dipole moment
Calculations of the BaF-Ar triatomic system are performed with a relativistic
Hamiltonian and coupled cluster theory at the CCSD(T) level for 1386 positions
of the Ar atom relative to the BaF molecule. Calculations are repeated with
increasing basis sets (double-, triple-, quadruple- and quintuple-zeta), and
these are extrapolated to estimate the complete-basis-set limit. The resulting
energies provide a potential energy for the interaction of an Ar atom with a
BaF molecule. A fit is presented that parametrizes this potential. This work is
needed for an understanding of the position, modes of motion and energy shifts
of BaF isolated in an Ar matrix. This understanding will guide the EDM
collaboration in its pursuit of a precision measurement of the electron
electric dipole moment using BaF isolated in a cryogenic Ar matrix
20 T Compact Superconducting Outsert Employing Y123 Coated Conductors for a 45 T Hybrid Magnet
Infrared magneto-optical properties of (III,Mn)V ferromagetic semiconductors
We present a theoretical study of the infrared magneto-optical properties of
ferromagnetic (III,Mn)V semiconductors. Our analysis combines the kinetic
exchange model for (III,Mn)V ferromagnetism with Kubo linear response theory
and Born approximation estimates for the effect of disorder on the valence band
quasiparticles. We predict a prominent feature in the ac-Hall conductivity at a
frequency that varies over the range from 200 to 400 meV, depending on Mn and
carrier densities, and is associated with transitions between heavy-hole and
light-hole bands. In its zero frequency limit, our Hall conductivity reduces to
the -space Berry's phase value predicted by a recent theory of the
anomalous Hall effect that is able to account quantitatively for experiment. We
compute theoretical estimates for magnetic circular dichroism, Faraday
rotation, and Kerr effect parameters as a function of Mn concentration and free
carrier density. The mid-infrared response feature is present in each of these
magneto-optical effects.Comment: 11 pages, 5 figure
The association of pain with suicidal ideation and suicide attempts with depressive symptoms among adults aged ≥50 years from low- and middle-income countries
Objectives: We aimed to examine the relationship of pain with suicidal ideation and suicide attempts with depressive symptoms among adults aged ≥50 years from six low- and middle-income countries (LMICs) (China, Ghana, India, Mexico, Russia, and South Africa). Methods: Cross-sectional, community-based, nationally representative data from the WHO Study on global AGEing and adult health were analyzed. Self-reported information on past 12-month suicidal ideation and suicide attempts among people with depressive symptoms was collected. Pain was assessed with the question “Overall in the last 30 days, how much of bodily aches or pain did you have?” With answer options: “none”, “mild”, “moderate”, “severe/extreme”. Multivariable logistic regression was done to assess associations. Results: Data on 34,129 adults aged ≥50 years (mean [SD] age 62.4 [16.0] years; males 47.9%) were analyzed. Compared to no pain, mild, moderate, and severe/extreme pain were associated with 2.83 (95% CI = 1.51–5.28), 4.01 (95% CI = 2.38–6.76), and 12.26 (95% CI = 6.44–23.36) times higher odds for suicidal ideation. For suicide attempt, only severe/extreme pain was associated with significantly increased odds (OR = 4.68; 95% CI = 1.67–13.08). Conclusions: In this large sample of older adults from multiple LMICs, pain was strongly associated with suicidal thoughts and suicide attempts with depressive symptoms. Future studies should assess whether addressing pain among older people in LMICs may lead to reduction in suicidal thoughts and behaviors
Lifetime self-reported arthritis is associated with elevated levels of mental health burden: A multi-national cross sectional study across 46 low- and middle-income countries
Population-based studies investigating the relationship of arthritis with mental health outcomes are lacking, particularly among low- and middle-income countries (LMICs). We investigated the relationship between arthritis and mental health (depression spectrum, psychosis spectrum, anxiety, sleep disturbances and stress) across community-dwelling adults aged ≥18 years across 46 countries from the World Health Survey. Symptoms of psychosis and depression were established using questions from the Mental Health Composite International Diagnostic Interview. Severity of anxiety, sleep problems, and stress sensitivity over the preceding 30 days were self-reported. Self-report lifetime history of arthritis was collected, including presence or absence of symptoms suggestive of arthritis: pain, stiffness or swelling of joints over the preceding 12-months. Multivariable logistic regression analyses were undertaken. Overall, 245,706 individuals were included. Having arthritis increased the odds of subclinical psychosis (OR = 1.85; 95%CI = 1.72–1.99) and psychosis (OR = 2.48; 95%CI = 2.05–3.01). People with arthritis were at increased odds of subsyndromal depression (OR = 1.92; 95%CI = 1.64–2.26), a brief depressive episode (OR = 2.14; 95%CI = 1.88–2.43) or depressive episode (OR = 2.43; 95%CI = 2.21–2.67). Arthritis was also associated with increased odds for anxiety (OR = 1.75; 95%CI = 1.63–1.88), sleep problems (OR = 2.23; 95%CI = 2.05–2.43) and perceived stress (OR = 1.43; 95%CI = 1.33–1.53). Results were similar for middle-income and low-income countries. Integrated interventions addressing arthritis and mental health comorbidities are warranted to tackle this considerable burden
Correlates of physical activity among community-dwelling adults aged 50 or over in six low- and middle-income countries
Background:
Considering that physical activity is associated with healthy ageing and helps to delay, prevent, or manage a plethora of non-communicable diseases in older adults, there is a need to investigate the factors that influence physical activity participation in this population. Thus, we investigated physical activity correlates among community-dwelling older adults (aged ≥50 years) in six low- and middle-income countries.
Methods:
Cross-sectional data were analyzed from the World Health Organization’s Study on Global Ageing and Adult Health. Physical activity was assessed by the Global Physical Activity Questionnaire. Participants were dichotomized into low (i.e., not meeting 150 minutes of moderate physical activity per week) and moderate-to-high physically active groups. Associations between physical activity and a range of correlates were examined using multivariable logistic regressions.
Results:
The overall prevalence (95%CI) of people not meeting recommended physical activity levels in 34,129 participants (mean age 62.4 years, 52.1% female) was 23.5% (22.3%-24.8%). In the multivariable analysis, older age and unemployment were significant sociodemographic correlates of low physical activity. Individuals with low body mass index (<18.5kg/m2), bodily pain, asthma, chronic back pain, chronic obstructive pulmonary disease, hearing problems, stroke, visual impairment, slow gait, and weak grip strength were less likely to meet physical activity targets in the overall sample (P<0.05). The associations varied widely between countries.
Conclusion:
Our data illustrates that a multitude of factors influence physical activity target achievement in older adults, which can inform future interventions across low- and middle-income countries to assist people of this age group to engage in regular physical activity. Future prospective cohort studies are also required to investigate the directionality and mediators of the relationships observed
Expression of UV-Sensitive Parapinopsin in the Iguana Parietal Eyes and Its Implication in UV-Sensitivity in Vertebrate Pineal-Related Organs
The pineal-related organs of lower vertebrates have the ability to discriminate different wavelengths of light. This wavelength discrimination is achieved through antagonistic light responses to UV or blue and visible light. Previously, we demonstrated that parapinopsin underlies the UV reception in the lamprey pineal organ and identified parapinopsin genes in teleosts and frogs of which the pineal-related organs were reported to discriminate light. In this study, we report the first identification of parapinopsin in the reptile lineage and show its expression in the parietal eye of the green iguana. Spectroscopic analysis revealed that iguana parapinopsin is a UV-sensitive pigment, similar to lamprey parapinopsin. Interestingly, immunohistochemical analyses using antibodies specific to parapinopsin and parietopsin, a parietal eye green-sensitive pigment, revealed that parapinopsin and parietopsin are colocalized in the outer segments of the parietal eye photoreceptor cells in iguanas. These results strongly suggest that parapinopsin underlies the wavelength discrimination involving UV reception in the iguana parietal eye. The current findings support the idea that parapinopsin is a common photopigment underlying the UV-sensitivity in wavelength discrimination of the pineal-related organs found from lampreys to reptiles
Schottky barrier heights at polar metal/semiconductor interfaces
Using a first-principle pseudopotential approach, we have investigated the
Schottky barrier heights of abrupt Al/Ge, Al/GaAs, Al/AlAs, and Al/ZnSe (100)
junctions, and their dependence on the semiconductor chemical composition and
surface termination. A model based on linear-response theory is developed,
which provides a simple, yet accurate description of the barrier-height
variations with the chemical composition of the semiconductor. The larger
barrier values found for the anion- than for the cation-terminated surfaces are
explained in terms of the screened charge of the polar semiconductor surface
and its image charge at the metal surface. Atomic scale computations show how
the classical image charge concept, valid for charges placed at large distances
from the metal, extends to distances shorter than the decay length of the
metal-induced-gap states.Comment: REVTeX 4, 11 pages, 6 EPS figure
Telomerase activity of the Lugol-stained and -unstained squamous epithelia in the process of oesophageal carcinogenesis
Up-regulation of telomerase has been reported in many cancers. Our aim was to characterize telomerase activity in various states of the oesophagus to facilitate better understanding of carcinogenesis of oesophageal squamous cell carcinoma. During endoscopic examinations, we obtained 45 Lugol-stained normal epithelia, 31 Lugol-unstained epithelia (14 oesophagitis, 7 mild dysplasia, 5 severe dysplasia and 5 intramucosal cancer) and 9 advanced cancer. Telomerase activity was semi-quantified by a telomeric repeat amplification protocol using enzyme-linked immunosorbent assay, and expression of human telomerase reverse transcriptase mRNA was examined by in situ hybridization. In the Lugol-stained normal epithelia, telomerase activity increased in proportion to the increase of severity of the accompanying lesions, with a rank order of advanced cancer, intramucosal cancer, mild dysplasia and oesophagitis. In the Lugol-unstained lesions and advanced cancer, telomerase activity was highest in advanced cancer. Up-regulation of telomerase in normal squamous epithelium may be a marker of progression of oesophageal squamous cell carcinoma. Copyright 2001 Cancer Research Campaign © 2001 Cancer Research Campaignhttp://www.bjcancer.co
HIV-1 competition experiments in humanized mice show that APOBEC3H imposes selective pressure and promotes virus adaptation
APOBEC3 (A3) family proteins are DNA cytosine deaminases recognized for contributing to
HIV-1 restriction and mutation. Prior studies have demonstrated that A3D, A3F, and A3G
enzymes elicit a robust anti-HIV-1 effect in cell cultures and in humanized mouse models.
Human A3H is polymorphic and can be categorized into three phenotypes: stable, intermediate,
and unstable. However, the anti-viral effect of endogenous A3H in vivo has yet to be
examined. Here we utilize a hematopoietic stem cell-transplanted humanized mouse model
and demonstrate that stable A3H robustly affects HIV-1 fitness in vivo. In contrast, the selection
pressure mediated by intermediate A3H is relaxed. Intriguingly, viral genomic RNA
sequencing reveled that HIV-1 frequently adapts to better counteract stable A3H during replication
in humanized mice. Molecular phylogenetic analyses and mathematical modeling
suggest that stable A3H may be a critical factor in human-to-human viral transmission.
Taken together, this study provides evidence that stable variants of A3H impose selective
pressure on HIV-1
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