442 research outputs found

    Intrinsic optical dichroism in the chiral superconducting state of Sr2_{2}RuO4_{4}

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    We present an analysis of the Hall conductivity σxy(ω,T)\sigma_{xy}(\omega, T) in time reversal symmetry breaking states of exotic superconductors. We find that the dichroic signal is non-zero in systems with inter-band order parameters. This new intrinsic mechanism may explain the Kerr effect observed in strontium ruthenate and possibly other superconductors. We predict coherence factor effects in the temperature dependence of the imaginary part of the ac Hall conductivity Imσxy(ω,T) Im\sigma_{xy}(\omega, T), which can be tested experimentally.Comment: 4+ pages, 4 figures, published versio

    Superconductivity and incommensurate spin fluctuations in a generalized t-J model for the cuprates

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    We consider the slave-fermion Schwinger-boson decomposition of an effective model obtained through a systematic low-energy reduction of the three-band Hubbard Hamiltonian. The model includes a three-site term t'' similar to that obtained in the large-U limit of the Hubbard model but of opposite sign for realistic or large O-O hopping. For parameters close to the most realistic ones for the cuprates, the mean-field solution exhibits d+s superconductivity (predominantly d_{x^2-y^2}) with a dependence on doping x very similar to the experimentally observed. We also obtained incommensurate peaks at wave vectors near π(1,1+(−)2x)\pi (1,1 +(-) 2x) in the spin structure factor, which also agree with experiment.Comment: 9 pages, latex, 2 figures, to appear in Europhys. Let

    The Older the Better: Infanticide Is Age-Related for Both Victims and Perpetrators in Captive Long-Tailed Macaques

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    In wild primates, infanticide is a risk that is especially prevalent when a new male takes over the alpha position. Insight into risk factors related to infanticide may decrease the incidence of infanticide in captivity during male introductions. We investigated several risk factors of infanticide derived from hypotheses explaining infanticide in the wild and tested this in captive long-tailed macaques (Macaca fascicularis) using demographic data spanning a 25.5-year period. Factors that are related to infanticide in the wild explained a large proportion, but not all incidences, of infanticide in captivity. Consistent with the wild data, infants young enough to decrease the interbirth interval (<215 days) were at risk of being killed. In contrast to studies from the wild, infanticidal males were more than 2.5 years younger than non-infanticidal males. This indicates that captive settings can lead to new risks since relatively young males may gain the alpha position, promoting infanticide. Therefore, we propose the adolescent male risk hypothesis as a captive risk factor in which subadult males pose a risk of infanticide. In conclusion, the ages of both males and infants are related to infanticide in captivity and have to be taken into account during male introductions

    The impact of energetic electron precipitation on mesospheric hydroxyl during a year of solar minimum

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    In 2008 a sequence of geomagnetic storms occurred triggered by high-speed solar wind streams from coronal holes. Improved estimates of precipitating fluxes of energetic electrons are derived from measurements on board the NOAA/POES 18 satellite using a new analysis technique. These fluxes are used to quantify the direct impact of energetic electron precipitation (EEP) during solar minimum on middle atmospheric hydroxyl (OH) measured from the Aura satellite. During winter, localized longitudinal density enhancements in the OH are observed over northern Russia and North America at corrected geomagnetic latitudes poleward of 55°. Although the northern Russia OH enhancement is closely associated with increased EEP at these longitudes, the strength and location of the North America enhancement appear to be unrelated to EEP. This OH density enhancement is likely due to vertical motion induced by atmospheric wave dynamics that transports air rich in atomic oxygen and atomic hydrogen downward into the middle atmosphere, where it plays a role in the formation of OH. In the Southern Hemisphere, localized enhancements of the OH density over West Antarctica can be explained by a combination of enhanced EEP due to the local minimum in Earth's magnetic field strength and atmospheric dynamics. Our findings suggest that even during solar minimum, there is substantial EEP-driven OH production. However, to quantify this effect, a detailed knowledge of where and when the precipitation occurs is required in the context of the background atmospheric dynamics.publishedVersio

    Rationale and design of the CORE (COrticosteroids REvised) study:protocol

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    Introduction Corticosteroids are an important pillar in many anti-inflammatory and immunosuppressive treatment regimens and are available in natural and synthetic forms, which are considered equipotent if clinical bioequivalence data are used. Current clinical bioequivalence data are however based on animal studies or studies with subjective endpoints. Furthermore, advancement in steroid physiology with regard to metabolism, intracellular handling and receptor activation have not yet been incorporated. Therefore, this study aims to re-examine the clinical bioequivalence and dose effects of the most widely used synthetic corticosteroids, prednisolone and dexamethasone. Methods and analysis In this double-blind, randomised cross-over clinical trial, 24 healthy male and female volunteers aged 18-75 years, will be included. All volunteers will randomly receive either first a daily dose of 7.5 mg prednisolone for 1 week, immediately followed by a daily dose of 30 mg prednisolone for 1 week, or first a presumed clinical bioequivalent dose of 1.125 mg dexamethasone per day, immediately followed by 4.5 mg of dexamethasone per day for 1 week. After a wash-out period of 4-8 weeks, the other treatment will be applied. The primary study endpoint is the difference in free cortisol excretion in 24 hours urine. Secondary endpoints will include differences in immunological parameters, blood pressure and metabolic measurements. Ethics and dissemination This study has been approved by the Medical Ethics Committee of the University Medical Center Groningen (METC 2020.398). The results of this study will be submitted for publication in peer-reviewed journals

    Maternal Anxiety, Infant Stress, and the Role of Live-Performed Music Therapy during NICU Stay in The Netherlands

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    Having an infant in the neonatal intensive care unit (NICU) elicits maternal anxiety, which may hamper parent−child bonding. We performed a prospective cohort study to describe anxiety in mothers of infants born before 30 weeks of gestation during NICU stay in The Netherlands, and investigated the influence of infant stress and gestational age. Second, we performed a randomized-controlled live-performed music therapy trial (LPMT trial) to investigate whether music therapy applied to the infant alleviated maternal anxiety. The relation between infant stress, gestational age, and maternal anxiety was measured in 45 mother−infant dyads, using the Neonatal Infant Stressor Scale and the State-Trait Anxiety Inventory (STAI). The effect of LPMT on anxiety was assessed in 21 mothers whose infants were assigned to either LPMT (n = 12) or waitlist (n = 9). Mothers completed the STAI before and after this period. Maternal anxiety decreased over time in all mothers, and was strongly related with infant stress (r = 0.706, p < 0.001), but not with gestational age. Anxiety scores decreased by 12% after LMPT, and increased by 1% after a waitlist period (p = 0.30). Our results indicate that LPMT in the weeks after birth may accelerate the reduction of maternal anxiety. Further research should focus on the effects on mother−child bonding

    Immune Activation Caused By Vascular Oxidation Promotes Fibrosis And Hypertension

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    Vascular oxidative injury accompanies many common conditions associated with hypertension. In the present study, we employed mouse models with excessive vascular production of ROS (tg(sm/p22phox) mice, which overexpress the NADPH oxidase subunit p22(phox) smooth muscle, and mice with vascular-specific deletion of extracellular SOD) and have shown that these animals develop vascular collagen deposition, aortic stiffening, renal dysfunction, and hypertension with age. T cells from tg(5m/p22phox) mice produced high levels of IL-17A and IFN-gamma. Crossing tg(sm/p22phox) mice with lymphocyte-deficient Rag1(-/-) mice eliminated vascular inflammation, aortic stiffening, renal dysfunction, and hypertension; however, adoptive transfer of T cells restored these processes. Isoketal-protein adducts, which are immunogenic, were increased in aortas, DCs, and macrophages of tg(sm/P22Phox) mice. Autologous pulsing with tg(sm/p22phox) aortic homogenates promoted DCs of tg(sm/p22phox) mice to stimulate T cell proliferation and production of IFN-gamma, IL-17A, and TNF-alpha. Treatment with the superoxide scavenger tempol or the isoketal scavenger 2-hydroxybenzylamine (2-HOBA) normalized blood pressure; prevented vascular inflammation, aortic stiffening, and hypertension; and prevented DC and T cell activation. Moreover, in human aortas, the aortic content of isoketal adducts correlated with fibrosis and inflammation severity. Together, these results define a pathway linking vascular oxidant stress to immune activation and aortic stiffening and provide insight into the systemic inflammation encountered in common vascular diseases.12615067NIH [DK059637, DK020593]NIH R01 [HL105294, HL039006, HL108701]VITA [HHSN268201400010C]American Heart Association predoctoral fellowship [13PRE14480008]NIH K08 [1K08HL121671]Vanderbilt Physician Scientist Development AwardNIH F32 [1F32HL124972-01][P01 HL58000

    Abundant kif21b is associated with accelerated progression in neurodegenerative diseases

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    Kinesin family member 21b (kif21b) is one of the few multiple sclerosis (MS) risk genes with a presumed central nervous system function. Kif21b belongs to the kinesin family, proteins involved in intracellular transport of proteins and organelles. We hypothesised that kif21b is involved in the neurodegenerative component of MS and Alzheimer¿s (AD) disease. Post-mortem kinesin expression was assessed in 50 MS, 58 age and gender matched non-demented controls (NDC) and 50 AD. Kif21b expression was five-fold increased in AD compared to MS and NDC aged below 62 years (p¿=¿8*10¿5), three-fold between 62¿72 years (p¿=¿0.005) and not different above 72 years. No significant differences were observed between MS and NDC. In AD, kif21b expression was two-fold increased in Braak stage 6 (scoring for density of neurofibrillary tangles) compared with stage 5 (p¿=¿0.003). In MS patients, kif21b correlated with the extent of grey matter demyelination (Spearman¿s rho¿=¿0.31, p¿=¿0.03). Abundant kif21b, defined as expression above the median, was associated with a two-fold accelerated development of the Kurtzke Expanded Disability Status Scale (EDSS) 6.0 (median time in low kif21b group 16 years vs. high kif21b 7.5 years, log-rank test p¿=¿0.04) in MS. Given the genetic association of kif21b with MS, the results were stratified according to rs12122721[A] single nucleotide polymorphism (SNP). No association was found between kif21b expression or the time to EDSS 6 in kif21b risk SNP carriers compared to non-risk carriers. Kif21b was expressed in astrocytes in addition to neurons. Upon astrocyte activation, kif21b increased nine-fold. Abundant kif21b expression is associated with severe MS and AD pathology and with accelerated neurodegeneration independent of the kif21b risk SNP

    Pain, fatigue, depressive symptoms and sleep disturbance in young adults with cerebral palsy

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    Purpose: Investigate pain, fatigue, depressive symptoms and sleep disturbance in young adults with cerebral palsy compared to references. Materials and methods: Young adults with cerebral palsy (n = 97, aged 21-34 years) and age-matched references from the general population (n = 190) rated pain using a numeric rating scale and fatigue, depressive symptoms, sleep disturbance and global health using Patient-Reported Outcomes Measurement Information System (R) short forms. Scores were compared between cerebral palsy subgroups and the reference population. Correlation coefficients and linear regression analyses assessed interrelationships of health issues and associations with global health. Results: Individuals with Gross Motor Function Classification System level I had less pain, fatigue and depressive symptoms, while individuals with levels II and III-V had more pain (53% and 56%, p <0.001) and those with levels III-V more fatigue (39%, p = 0.035) than references (pain: 26%, fatigue: 14%). Pain and fatigue were more interrelated (correlation coefficients: 0.71 vs. 0.41) and stronger associated with global mental health in individuals with cerebral palsy. Conclusions: Young adults with Gross Motor Function Classification System levels II-V report more pain and those with levels III-V report more fatigue than references. Pain and fatigue are highly interrelated and specifically relate to mental health in individuals with cerebral palsy
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