Yb4LiGe4 - A Yb Mixed Valent Zintl Phase with Strong Electronic Correlations

Single-phase samples of Yb4LiGe4 and Yb5Ge4 were synthesized using high frequency (HF) heat treatment. Yb4LiGe4 crystallizes in orthorhombic space group Pnma with the Gd5Si4 type of crystal structure and lattice parameters a = 7.0571(1) Angs, b = 14.6239(1) Angs, and c = 7.6155(1) Angs. One Yb position in Yb5Ge4 is substituted by the lithium atom and causes a distortion of the germanium tetragons in Yb4LiGe4. Investigation of the electronic state of Yb via magnetic susceptibility and X-ray absorption near-edge spectroscopy (XANES) revealed a presence of two electronic states of ytterbium, 4f13 and 4f14 (mixed valence), in Yb5Ge4 and Yb4LiGe4. Studies of the temperature dependence of the electrical resistivity, magnetization, 7Li spin-lattice relaxation rate and the specific heat indicate that strong electronic correlations are present in Yb4LiGe4, and below approximately 50 K there is a competition between ferromagnetic and antiferromagnetic correlations. Magnetic ordering in Yb4LiGe4, if present, occurs below the reported antiferromagnetic transition temperature of 1.7 K for Yb5Ge4.Comment: 27 Pages, 9 figures, Uncder revie

Determination of the Bending Rigidity of Graphene via Electrostatic Actuation of Buckled Membranes

The small mass and atomic-scale thickness of graphene membranes make them highly suitable for nanoelectromechanical devices such as e.g. mass sensors, high frequency resonators or memory elements. Although only atomically thick, many of the mechanical properties of graphene membranes can be described by classical continuum mechanics. An important parameter for predicting the performance and linearity of graphene nanoelectromechanical devices as well as for describing ripple formation and other properties such as electron scattering mechanisms, is the bending rigidity, {\kappa}. In spite of the importance of this parameter it has so far only been estimated indirectly for monolayer graphene from the phonon spectrum of graphite, estimated from AFM measurements or predicted from ab initio calculations or bond-order potential models. Here, we employ a new approach to the experimental determination of {\kappa} by exploiting the snap-through instability in pre-buckled graphene membranes. We demonstrate the reproducible fabrication of convex buckled graphene membranes by controlling the thermal stress during the fabrication procedure and show the abrupt switching from convex to concave geometry that occurs when electrostatic pressure is applied via an underlying gate electrode. The bending rigidity of bilayer graphene membranes under ambient conditions was determined to be $35.5^{+20}_{-15}$ eV. Monolayers have significantly lower {\kappa} than bilayers

Measuring the optical concurrence of vector beams with an atomic-state interferometer

We investigate the transmission of vector beams, correlated in their polarization and spatial degrees of freedom, through cold atoms in the presence of a transverse magnetic coupling field. The resulting phase-dependent dynamics allow us to imprint the spatially varying polarization of a vector beam onto atomic spin polarizations, thereby establishing a direct link between optical space-polarization correlations and atomic-state interference. We find that the resulting absorption profiles show interference fringes whose modulation strength is given by the squared concurrence of the vector beam, letting us identify optical concurrence from a single absorption image. We expect impact across a diverse range of applications, including spintronics, quantum memories, metrology, and clocks

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Yb4LiGe4\mathrm{Yb_{4}LiGe_{4}} – A Yb mixed valent Zintl phase with strong electronic correlations

Single-phase samples of Yb$_{4}$LiGe$_{4}$ and Yb$_{5}$LiGe$_{4}$ were synthesized using high frequency (HF) heat treatment. Yb$_{4}$LiGe$_{4}$ crystallizes in orthorhombic space group Pnma with the Gd$_5$Si$_4$ type of crystal structure and lattice parameters a = 7.0828(3) Å, b = 14.6415(7) Å, and c = 7.6279(4) Å. One Yb position in Yb$_{5}$LiGe$_{4}$ is substituted by the lithium atom and causes a distortion of the germanium tetragons in Yb$_{4}$LiGe$_{4}$. Investigation of the electronic state of Yb via magnetic susceptibility and X-ray absorption near-edge spectroscopy (XANES) revealed a presence of two electronic states of ytterbium, 4f$^{13}$ and 4f$^{14}$ (mixed valence), in Yb$_{5}$LiGe$_{4}$ and Yb$_{4}$LiGe$_{4}$. Studies of the temperature dependence of the electrical resistivity, magnetization, 7Li spin-lattice relaxation rate and the specific heat indicate that strong electronic correlations are present in Yb$_{4}$LiGe$_{4}$, and below approximately 50 K there is a competition between ferromagnetic and antiferromagnetic correlations. Magnetic ordering in Yb$_{4}$LiGe$_{4}$, if present, occurs below the reported antiferromagnetic transition temperature of 1.7 K for Yb$_{5}$LiGe$_{4}$

Estimated glomerular filtration rate is associated with major bleeding complications but not thromboembolic events, in anticoagulated patients taking warfarin.

BACKGROUND: Decreased glomerular filtration rate is an established risk factor for bleeding but there are limited data on its association with bleeding risk in well-controlled anticoagulated patients taking warfarin. OBJECTIVES: The aim was to investigate the relationship between glomerular filtration rate, major bleeding and thromboembolic complications in patients with tight anticoagulation control. PATIENTS/METHODS: A cohort study of patients from a Swedish quality register for anticoagulation, including all the registered patients that received anticoagulation during 2008 in the anticoagulation center of Skåne University Hospital, Malmö. Key outcome measures were major bleeding and arterial or venous thrombosis during 2008. A total of 3536 patients (2875 treatment years) were included. RESULTS: Total rates of 2.6 (2.0-3.2) bleeding events and 1.8 (1.3-2.3) thrombotic events per 100 treatment years were recorded (75 bleeding and 51 thromboembolic events). Data on estimated glomerular filtration rate were available in 3349 patients. Mean time in therapeutic range (international normalized ratio 2.0-3.0) was 74.5% (n=2894). Major bleeding events were significantly related to age and percentage of time with international normalized ratio >3.0 (P<0.001). Glomerular filtration rate levels <30ml/min/1.73m(2) were particularly associated with high risk of bleeding, especially in elderly patients. No correlation between glomerular filtration rate and thromboembolic events was seen. CONCLUSIONS: With good anticoagulation control as measured by time in therapeutic range, patients had a relatively low risk for major bleeding if their renal function is normal. Despite good anticoagulation control, severely impaired kidney function is associated with a very high yearly risk of major bleeding events

Attenuated mTOR Signaling and Enhanced Autophagy in Adipocytes from Obese Patients with Type 2 Diabetes

Type 2 diabetes (T2D) is strongly linked to obesity and an adipose tissue unresponsive to insulin. The insulin resistance is due to defective insulin signaling, but details remain largely unknown. We examined insulin signaling in adipocytes from T2D patients, and contrary to findings in animal studies, we observed attenuation of insulin activation of mammalian target of rapamycin (mTOR) in complex with raptor (mTORC1). As a consequence, mTORC1 downstream effects were also affected in T2D: feedback signaling by insulin to signal-mediator insulin receptor substrate-1 (IRS1) was attenuated, mitochondria were impaired and autophagy was strongly upregulated. There was concomitant autophagic destruction of mitochondria and lipofuscin particles, and a dependence on autophagy for ATP production. Conversely, mitochondrial dysfunction attenuated insulin activation of mTORC1, enhanced autophagy and attenuated feedback to IRS1. The overactive autophagy was associated with large numbers of cytosolic lipid droplets, a subset with colocalization of perlipin and the autophagy protein LC3/atg8, which can contribute to excessive fatty acid release. Patients with diagnoses of T2D and overweight were consecutively recruited from elective surgery, whereas controls did not have T2D. Results were validated in a cohort of patients without diabetes who exhibited a wide range of insulin sensitivities. Because mitochondrial dysfunction, inflammation, endoplasmic-reticulum stress and hypoxia all inactivate mTORC1, our results may suggest a unifying mechanism for the pathogenesis of insulin resistance in T2D, although the underlying causes might differ