483 research outputs found
Spin-Waves in the Mid-Infrared Spectrum of Antiferromagnetic YBaCuO
The mid-infrared spin-wave spectrum of antiferromagnetic
YBaCuO\ was determined by infrared transmission and reflection
measurements (\bbox{k} \!\! \parallel c) at ~K.\@ Excitation of
single magnons of the optical branch was observed at
~meV.\@ Two further peaks at ~meV
() and ~meV
() both belong to the two-magnon spectrum. Linear
spin wave theory is in good agreement with the measured two-magnon spectrum,
and allows to determine the exchange constant to be about ~meV,
whereas the intrabilayer coupling is approximately .Comment: 3 figures in uuencoded for
Acute exposure to simulated nocturnal train noise leads to impaired sleep quality and endothelial dysfunction in young healthy men and women: a sex-specific analysis
A series of human field studies demonstrated that simulated nocturnal traffic noise exposure impaired sleep quality and endothelial function, which could be significantly improved after intake of vitamin C in case of endothelial function. However, it remains unclear whether these changes follow a sex-specific pattern. Thus, we aimed to analyze the effect of simulated nocturnal train noise exposure on sleep quality, endothelial function and its associated changes after vitamin C intake, and other hemodynamic and biochemical parameters in young healthy men and women. We used data from a randomized crossover study, wherein 70 healthy volunteers (50% women) were each exposed to one control pattern (regular background noise) and two different train noise scenarios (30 or 60 train noise events per night, with average sound pressure levels of 52 and 54 dB(A), respectively, and peak sound level of 73-75 dB(A)) in their homes for three nights. After each night, participants visited the study center for the measurement of endothelial function as well as other hemodynamic and biochemical parameters. Sleep quality measured via self-report was significantly impaired after noise 30 and noise 60 nights in both men and women (p < 0.001 vs. control). Likewise, endothelial function measured by flow-mediated dilation (FMD) was significantly impaired after noise 30 and noise 60 nights in both men and women (p < 0.001 vs. control). While in women, vitamin C intake significantly improved FMD after both noise 30 and noise 60 study nights compared to control nights, no significant changes were observed in men. Exposure to simulated nocturnal train noise impairs sleep quality and endothelial function in both men and women, whereas a significant improvement of endothelial function after noise exposure and vitamin C intake could only be observed in women. These findings suggest for the first time that in men other mechanisms such as oxidative stress causing endothelial dysfunction may come into play
Vascular effects and safety of dalcetrapib in patients with or at risk of coronary heart disease: the dal-VESSEL randomized clinical trial
Aims High-density lipoprotein cholesterol (HDL-C) is inversely associated with cardiovascular (CV) events and thus an attractive therapeutic target. However, in spite of marked elevations in HDL-C, the first cholesterol transport protein (CETP) inhibitor torcetrapib raised blood pressure (BP), impaired endothelial function, and increased CV mortality and morbidity. Dalcetrapib is a novel molecule acting on CETP with a different chemical structure to torcetrapib. As HDL stimulates nitric oxide (NO), suppresses inflammation, and exerts protective CV effects, we investigated the effects of dalcetrapib on endothelial function, blood pressure, inflammatory markers, and lipids in patients with, or at risk of, coronary heart disease (CHD) in a double-blind randomized placebo-controlled trial (clinicaltrials.gov number NCT00655538). Methods and results Patients with target low-density lipoprotein cholesterol (LDL-C) levels received dalcetrapib 600 mg/day or placebo for 36 weeks on top of standard therapy (including statins). The primary outcome measures were the change from baseline of flow-mediated dilatation (%FMD) of the right brachial artery after 5 min of cuff occlusion at 12 weeks and the 24 h ambulatory blood pressure monitoring (ABPM) at week 4. Secondary outcomes included change from baseline in FMD after 36 weeks and the change in ABPM at 12 and 36 weeks, changes in HDL-C, LDL-C, triglycerides, CETP activity, as well as standard safety parameters. Four hundred seventy-six patients were randomized. Baseline FMD was 4.1 ± 2.2 and 4.0 ± 2.4% with placebo or dalcetrapib, respectively and did not change significantly from placebo after 12 and 36 weeks (P = 0.1764 and 0.9515, respectively). After 4, 24, and 36 weeks of treatment with dalcetrapib, CETP activity decreased by 51, 53, and 56% (placebo corrected, all P < 0.0001), while at weeks 4, 12, and 36 HDL-C increased by 25, 27, and 31% (placebo corrected, all P < 0.0001). Low-density lipoprotein cholesterol levels did not change. At baseline, ABPM was 125 ± 12/74 ± 8mmHg in the placebo and 128 ± 11/75 ± 7mmHg in the dalcetrapib group (P = 0.3372 and 0.1248, respectively, placebo-corrected change from baseline) and did not change for up to 36 weeks. Biomarkers of inflammation, oxidative stress, and coagulation did not change during follow-up except for Lp-PLA2 mass levels which increased by 17% (placebo corrected). Overall 7 patients given dalcetrapib and 8 patients given placebo experienced at least one pre-specified adjudicated event (11 events with dalcetrapib and 12 events with placebo). Conclusion The dal-VESSEL trial has established the tolerability and safety of CETP-inhibition with dalcetrapib in patients with or at risk of CHD. Dalcetrapib reduced CETP activity and increased HDL-C levels without affecting NO-dependent endothelial function, blood pressure, or markers of inflammation and oxidative stress. The dal-OUTCOMES trial (NCT00658515) will show whether dalcetrapib improves outcomes in spite of a lack of effect on endothelial functio
The ophthalmic branch of the Gutenberg Health Study: study design, cohort profile and self-reported diseases
This paper describes the study design, methodology, cohort profile and self-reported diseases in the ophthalmological branch of the Gutenberg Health Study (GHS).The GHS is an ongoing, prospective, interdisciplinary, single-center, population-based cohort study in Germany. The main goals of the ophthalmological section are to assess the prevalence and incidence of ocular diseases and to explore risk factors, genetic determinants and associations with systemic diseases and conditions. The eye examination at baseline included a medical history, self-reported eye diseases, visual acuity, refractive errors, intraocular pressure, visual field, pachymetry, keratometry, fundus photography and tear sampling. The 5-year follow-up visit additionally encompassed optical coherence tomography, anterior segment imaging and optical biometry. The general examination included anthropometry; blood pressure measurement; carotid artery ultrasound; electrocardiogram; echocardiography; spirometry; cognitive tests; questionnaires; assessment of mental conditions; and DNA, RNA, blood and urine sampling.Of 15,010 participants (aged 35-74 years at the time of inclusion), ocular data are available for 14,700 subjects (97.9%). The mean visual acuity (standard deviation), mean spherical equivalent, median decimal visual acuity, and mean intraocular pressure were 0.08 (0.17) logMar, -0.42 (2.43) diopters, 0.9 and 14.24 (2.79) mm Hg, respectively. The frequencies of self-reported strabismus, glaucoma, surgery for retinal detachment and retinal vascular occlusions were 2.7%, 2.3%, 0.2% and 0.4%, respectively.The GHS is the most extensive dataset of ophthalmic diseases and conditions and their risk factors in Germany and one of the largest cohorts worldwide. This dataset will provide new insight in the epidemiology of ophthalmic diseases and related medical specialties
Effects of gaseous and solid constituents of air pollution on endothelial function
Ambient air pollution is a leading cause of non-communicable disease globally. The largest proportion of deaths and morbidity due to air pollution is now known to be due to cardiovascular disorders. Several particulate and gaseous air pollutants can trigger acute events (e.g. myocardial infarction, stroke, heart failure). While the mechanisms by which air pollutants cause cardiovascular events is undergoing continual refinement, the preponderant evidence support rapid effects of a diversity of pollutants including all particulate pollutants (e.g. course, fine, ultrafine particles) and gaseous pollutants such as ozone, on vascular function. Indeed alterations in endothelial function seem to be critically important in transducing signals and eventually promoting cardiovascular disorders such as hypertension, diabetes, and atherosclerosis. Here, we provide an updated overview of the impact of particulate and gaseous pollutants on endothelial function from human and animal studies. The evidence for causal mechanistic pathways from both animal and human studies that support various hypothesized general pathways and their individual and collective impact on vascular function is highlighted. We also discuss current gaps in knowledge and evidence from trials evaluating the impact of personal-level strategies to reduce exposure to fine particulate matter (PM2.5) and impact on vascular function, given the current lack of definitive randomized evidence using hard endpoints. We conclude by an exhortation for formal inclusion of air pollution as a major risk factor in societal guidelines and provision of formal recommendations to prevent adverse cardiovascular effects attributable to air pollution
Infrared Conductivity in Layered -wave Superconductors
We calculate the infrared conductivity of a stack of coupled, two-dimensional
superconducting planes within the Fermi liquid theory of superconductivity. We
include the effects of random scattering processes and show that the presence
of even a small concentration of resonant impurities, in a -wave
superconductor, has an important effect on both the in-plane and -axis
transport properties, which could serve as signatures for -wave pairing.Comment: 18 pages in a RevTex (3.0) file plus 5 postscript figures
(uuencoded). Replaced with minor changes as it will appear in the Physical
Review B {\bf 52} issue 1 Oct. 199
Prevalence of depression and anxiety among participants with glaucoma in a population-based cohort study : the Gutenberg Health Study
Background
To investigate the prevalence of depression and anxiety among subjects with self-reported glaucoma and the association between self-reported glaucoma and depression respectively anxiety in a European cohort.
Methods
A study sample of 14,657 participants aged 35 to 74 years was investigated in a population-based cohort study. All participants reported presence or absence of glaucoma. Ophthalmological examinations were carried out in all participants and demographic and disease related information were obtained by interview. Depression was assessed with the Patient Health Questionnaire (PHQ-9), and generalized anxiety with the two screening items (GAD-2) of the short form of the GAD-7 (Generalized Anxiety Disorder-7 Scale). Prevalence of depression and generalized anxiety were investigated for subjects with and without self-reported glaucoma. Logistic regression analyses with depression, respectively anxiety as dependent variable and self-reported glaucoma as independent variable were conducted and adjusted for socio-demographic factors, systemic comorbidities (arterial hypertension, myocardial infarction, stroke, diabetes mellitus, chronic obstructive pulmonary disease, cancer), ocular diseases (cataract, macular degeneration, corneal diseases, diabetic retinopathy), visual acuity, intraocular pressure, antiglaucoma eye drops (sympathomimetics, parasympathomimetics, carbonic anhydrase inhibitors, beta-blockers, prostaglandins) and general health status.
Results
293 participants (49.5% female) reported having glaucoma. Prevalence of depression among participants with and without self-reported glaucoma was 6.6% (95%-CI 4.1–10.3) respectively 7.7% (95%-CI 7.3–8.2), and for anxiety 5.3% (95%-CI 3.1–8.7) respectively 6.6% (95%-CI 6.2–7.1). Glaucoma was not associated with depression (Odds ratio 1.10, 95%-CI 0.50–2.38, p = 0.80) or anxiety (1.48, 95%-CI 0.63–3.30, p = 0.35) after adjustment for socio-demographic factors, ocular/systemic diseases, ocular parameters, antiglaucoma drugs and general health status. A restriction to self-reported glaucoma cases either taking topical antiglaucoma medications or having a history of glaucoma surgery did not alter the result.
Conclusions
This is the first study analyzing both depression and anxiety among glaucoma patients in a European cohort. Subjects with and without self-reported glaucoma had a similar prevalence of depression and anxiety in our population-based sample. Self-reported glaucoma was not associated with depression or anxiety. A lack of a burden of depressive symptoms may result from recruitment from a population-based sample as compared to previous study groups predominantly recruited from tertiary care hospitals
An Alternative Pathway of Imiquimod-Induced Psoriasis-Like Skin Inflammation in the Absence of Interleukin-17 Receptor A Signaling
Topical application of imiquimod (IMQ) on the skin of mice induces inflammation with common features found in psoriatic skin. Recently, it was postulated that IL-17 has an important role both in psoriasis and in the IMQ model. To further investigate the impact of IL-17RA signaling in psoriasis, we generated IL-17 receptor A (IL-17RA)–deficient mice (IL-17RAdel) and challenged these mice with IMQ. Interestingly, the disease was only partially reduced and delayed but not abolished when compared with controls. In the absence of IL-17RA, we found persisting signs of inflammation such as neutrophil and macrophage infiltration within the skin. Surprisingly, already in the naive state, the skin of IL-17RAdel mice contained significantly elevated numbers of Th17- and IL-17-producing γδ T cells, assuming that IL-17RA signaling regulates the population size of Th17 and γδ T cells. Upon IMQ treatment of IL-17RAdel mice, these cells secreted elevated amounts of tumor necrosis factor-α, IL-6, and IL-22, accompanied by increased levels of the chemokine CXCL2, suggesting an alternative pathway of neutrophil and macrophage skin infiltration. Hence, our findings have major implications in the potential long-term treatment of psoriasis by IL-17-targeting drugs
No evidence for an association of plasma homocysteine levels and refractive error - Results from the population-based Gutenberg Health Study (GHS)
Purpose There is a strong association between severe hyperhomocysteinemia and myopia. Thus we studied the hypothesis that even moderately increased levels of homocysteine (Hcy) might be a potentially treatable risk factor for myopia. Methods The Gutenberg Health Study (GHS) is a population-based, prospective, observational cohort study in Germany, including 15,010 participants aged between 35 and 74 at recruitment. The baseline examination was conducted from 2007-2012. Refraction was measured using autorefraction (HARK 599, Carl Zeiss AG, Jena, Germany). Hcy was measured by an immunoassay. We included only phakic participants without a history of corneal surgery or corneal laser treatment. We used linear regression models to evaluate the potential association between Hcy and refraction at baseline, and between Hcy and change in refraction between baseline and 5-year-follow-up examination. We used generalized estimating equation models to account for the correlation between fellow eyes. Results We included 13,749 participants, categorized as having no myopia (spherical equivalent > -0.75 D, 65.2%), low myopia (-0.75 D-2.75 D, 21.5%), moderate myopia (-3.00 D- 5.75 D, 9.8%) and high myopia (≤ -6
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