Unidirectional Rashba spin splitting in single layer WS2(1-x)Se2xalloy.

Atomically thin two-dimensional (2D) layered semiconductors such as transition metal dichalcogenides have attracted considerable attention due to their tunable band gap, intriguing spin-valley physics, piezoelectric effects and potential device applications. Here we study the electronic properties of a single layer WS1.4Se0.6alloys. The electronic structure of this alloy, explored using angle resolved photoemission spectroscopy, shows a clear valence band structure anisotropy characterized by two paraboloids shifted in one direction of thek-space by a constant in-plane vector. This band splitting is a signature of a unidirectional Rashba spin splitting with a related giant Rashba parameter of 2.8 ± 0.7 eV Å. The combination of angle resolved photoemission spectroscopy with piezo force microscopy highlights the link between this giant unidirectional Rashba spin splitting and an in-plane polarization present in the alloy. These peculiar anisotropic properties of the WS1.4Se0.6alloy can be related to local atomic orders induced during the growth process due the different size and electronegativity between S and Se atoms. This distorted crystal structure combined to the observed macroscopic tensile strain, as evidenced by photoluminescence, displays electric dipoles with a strong in-plane component, as shown by piezoelectric microscopy. The interplay between semiconducting properties, in-plane spontaneous polarization and giant out-of-plane Rashba spin-splitting in this 2D material has potential for a wide range of applications in next-generation electronics, piezotronics and spintronics devices.

Hybridization and localized flat band in the WSe2/MoSe2heterobilayer.

Nearly localized moiré flat bands in momentum space, arising at particular twist angles, are the key to achieve correlated effects in transition-metal dichalcogenides. Here, we use angle-resolved photoemission spectroscopy (ARPES) to visualize the presence of a flat band near the Fermi level of van der Waals WSe2/MoSe2heterobilayer grown by molecular beam epitaxy. This flat band is localized near the Fermi level and has a width of several hundred meVs. By combining ARPES measurements with density functional theory calculations, we confirm the coexistence of different domains, namely the reference 2H stacking without layer misorientation and regions with arbitrary twist angles. For the 2H-stacked heterobilayer, our ARPES results show strong interlayer hybridization effects, further confirmed by complementary micro- Raman spectroscopy measurements. The spin-splitting of the valence band atKis determined to be 470 meV. The valence band maximum (VBM) position of the heterobilayer is located at the Γ point. The energy difference between the VBM at Γ and theKpoint is of -60 meV, which is a stark difference compared to individual single monolayer WSe2and monolayer WSe2, showing both a VBM atK.

Acute cholestasis as uncommon onset of Kawasaki disease: a case report.

BACKGROUND: Kawasaki disease (KD) or mucocutaneous lymph node syndrome is a vasculitis that mostly occurs in young children. Adult-onset KD (AKD) is rare and often misdiagnosed. Here we report a rare case of KD with cholestasis as principal symptom. CASE PRESENTATION: A 43-year-old caucasian man was admitted to our hospital for high fever, lack of appetite related to nausea and vomiting, headache and significant malaise. Physical examination highlighted fever, increasing jaundice, bilateral laterocervical lymph nodes, erythema of the palms, and strikingly red lips and conjunctiva. The clinical course was complicated by arterial hypotension, tachycardia, decreasing haemoglobin, increasing acute phase reactants tests, and multiorgan failure. Due to cardiovascular instability the patient was admitted to the local Intensive Care Unit. Chest X-ray, abdominal ultrasound, chest and abdominal CT and Colangio Magnetic Resonance were normal. Jaundice was investigated and infections, autoimmune diseases or drugs adverse reactions, were excluded. Also coronary artery computed tomography was carried out excluding coronary artery aneurysms. Broad-spectrum antibiotics were not effective. After exclusion other possible conditions, diagnosis of KD was set. He was treated with high doses of corticosteroids and acetylsalicylic acid and clinical conditions as well as laboratory exams improved. CONCLUSIONS: This report dealing with an adult onset of atypical KD may be of benefit to physicians of various specialties, including primary care doctors, hospital internists, intensivists and gastroenterologists due to its peculiarities. It demonstrates that a case of prolonged fever unresponsive to antibiotics and related to cholestatic jaundice, oedema or erythema of the extremity associated with desquamation of feet and hands, and red eyes, may suggest atypical form of KD.

High performance tunnel field effect transistors based on in-plane transition metal dichalcogenide heterojunctions.

In-plane heterojunction tunnel field effect transistors based on monolayer transition metal dichalcogenides are studied by means of self-consistent non-equilibrium Green's functions simulations and an atomistic tight-binding Hamiltonian. We start by comparing several heterojunctions before focusing on the most promising ones, i.e. WTe2-MoS2 and MoTe2-MoS2. The scalability of those devices as a function of channel length is studied, and the influence of backgate voltages on device performance is analyzed. Our results indicate that, by fine-tuning the design parameters, those devices can yield extremely low subthreshold swings (<5 mV/decade) and I ON/I OFF ratios higher than 108 at a supply voltage of 0.3 V, making them ideal for ultra-low power consumption.

The impact of dizziness on quality-of-life in the elderly.

Dizziness is a common medical condition that has been related to falls in the elderly, and it is, therefore, considered a severe social health problem. Particularly in the elderly, the impact of dizziness may be relevant, as it has been linked to several conditions, such as isolation, depression, reduced self autonomy, and self control. The social, functional, and psychological well-being of those affected can be hampered significantly, thus reducing the quality-of-life (QoL) perception. In addition, due to the aging of the population in the developed world, dizziness is becoming a growing public health problem; an optimal management of this condition includes, nowadays, the improvement of rehabilitative programs, as well as the evaluation of QoL status and its management. The aim of this paper is to evaluate the impact of dizziness on the QoL in the elderly, also analyzing the instruments available, nowadays, to evaluate QoL of dizzy patients.

Circaseptan Periodicity of Cardiovascular Diseases.

The occurrence of cardiovascular events shows a different distribution during the week, with many studies reporting a Monday peak, possibly related to the role of stress associated with commencing weekly activities. Furthermore, a higher mortality has been observed among patients hospitalized for cardiovascular and other disorders on weekends, a phenomenon known as "weekend effect." Such effect may be explained by a higher level of disease severity among patients admitted over the weekend, and/or by a poorer quality of care associated with shortage of staff, lower experience of personnel, and limited availability of therapeutic and diagnostic procedures.

Risk factors for renal disease and urinary abnormalities in men and women: data from the World Kidney Day in the province of Ferrara, Italy.

BACKGROUND: Chronic kidney disease (CKD) is a worldwide health problem due to its morbidity and mortality, and cost. World Kidney Day (WKD) has been planned to improve disease prevention. The aim of this study was to evaluate CKD risk factors and urinary abnormalities, collected on WKD along several years, in men and women. PATIENTS AND METHODS: Between 2006 and 2012, 1980 subjects, of whom 1012 women, from general population living in Ferrara area, a town in the north-east of Italy, were investigated. For each participant age, sex, smoking, hypertensive and diabetic status, body mass index (BMI), waist circumference (WC), and blood pressure (BP) were obtained. Moreover, body shape index (BSI) was calculated. All subjects underwent dipstick urinalysis. RESULTS: Men had higher BMI, WC, and BP than women. Women had higher prevalence of abdominal obesity and higher BSI (0.0951 ± 0.0105 vs. 0.0920 ± 0.0071 m(11/6)kg(-2/3)), while men had higher prevalence of overweight. In women, hematuria and leukocyturia were more prevalent (16.9% vs. 12.8%; OR 95%CI 1.161 (1.042-1.294); p = 0.012; 18.5% vs. 7% OR 95%CI 1.538 (1.403-1.676); p < 0.001, respectively), while glycosuria was less frequent (4.2% vs. 8.8% OR 95%CI 0.642 (0.501-0.822); p < 0.001) than in men. Frequency of proteinuria was similar in the two sexes. Venn diagrams indicate a different overlap of urinary abnormalities in the two sexes. CONCLUSIONS: Risk factors for CKD collected during the WKD appear to be different in the two sexes, and urinary abnormalities overlap differently. Data collected during the WKD are related to sex, and women deserve greater attention.

Quantum Confinement and Electronic Structure at the Surface of van der Waals Ferroelectric α-In2Se3.

Two-dimensional (2D) ferroelectric (FE) materials are promising compounds for next-generation nonvolatile memories due to their low energy consumption and high endurance. Among them, α-In2Se3 has drawn particular attention due to its in- and out-of-plane ferroelectricity, whose robustness has been demonstrated down to the monolayer limit. This is a relatively uncommon behavior since most bulk FE materials lose their ferroelectric character at the 2D limit due to the depolarization field. Using angle resolved photoemission spectroscopy (ARPES), we unveil another unusual 2D phenomenon appearing in 2H α-In2Se3 single crystals, the occurrence of a highly metallic two-dimensional electron gas (2DEG) at the surface of vacuum-cleaved crystals. This 2DEG exhibits two confined states, which correspond to an electron density of approximately 1013 electrons/cm2, also confirmed by thermoelectric measurements. Combination of ARPES and density functional theory (DFT) calculations reveals a direct band gap of energy equal to 1.3 ± 0.1 eV, with the bottom of the conduction band localized at the center of the Brillouin zone, just below the Fermi level. Such strong n-type doping further supports the quantum confinement of electrons and the formation of the 2DEG.

Quasi van der Waals Epitaxy of Rhombohedral-Stacked Bilayer WSe2 on GaP(111) Heterostructure.

The growth of bilayers of two-dimensional (2D) materials on conventional 3D semiconductors results in 2D/3D hybrid heterostructures, which can provide additional advantages over more established 3D semiconductors while retaining some specificities of 2D materials. Understanding and exploiting these phenomena hinge on knowing the electronic properties and the hybridization of these structures. Here, we demonstrate that a rhombohedral-stacked bilayer (AB stacking) can be obtained by molecular beam epitaxy growth of tungsten diselenide (WSe2) on a gallium phosphide (GaP) substrate. We confirm the presence of 3R-stacking of the WSe2 bilayer structure using scanning transmission electron microscopy (STEM) and micro-Raman spectroscopy. Also, we report high-resolution angle-resolved photoemission spectroscopy (ARPES) on our rhombohedral-stacked WSe2 bilayer grown on a GaP(111)B substrate. Our ARPES measurements confirm the expected valence band structure of WSe2 with the band maximum located at the Γ point of the Brillouin zone. The epitaxial growth of WSe2/GaP(111)B helps to understand the fundamental properties of these 2D/3D heterostructures, toward their implementation in future devices.

[Falls and renal function: a dangerous association]. / Cadute e funzione renale: un'associazione pericolosa.

Falls are an important health problem and the risk of falling increases with age. The costs due to falls are related to the progressive decline of patients' clinical conditions, with functional inability inducing increasing social costs, morbidity and mortality. Renal dysfunction is mostly present in elderly people who often have several comorbidities. Risk factors for falls have been classified as intrinsic and extrinsic, and renal dysfunction is included among the former. Chronic kidney disease per se is an important risk factor for falls, and the risk correlates negatively with creatinine clearance. Vitamin D deficiency, dysfunction of muscles and bones, nerve degeneration, cognitive decline, electrolyte imbalance, anemia, and metabolic acidosis have been reported to be associated with falls. Falls seem to be very frequent in dialysis patients: 44% of subjects on hemodialysis fall at least once a year with a 1-year mortality due to fractures of 64%. Male sex, comorbidities, predialysis hypotension, and a history of previous falls are the main risk factors, together with events directly related to renal replacement therapy such as biocompatibility of the dialysis membrane, arrhythmias, fluid overload and length of dialysis treatment. Peripheral nerve degeneration and demyelination as well as altered nerve conduction resulting in muscular weakness and loss of peripheral sensitivity are frequent when the glomerular filtration rate is less than 12 mL/min. Moreover, depression and sleep disorders can also increase the risk of falls. Kidney function is an important parameter to consider when evaluating the risk of falls in the elderly, and the development of specific guidelines for preventing falls in the uremic population should be considered.

Evidence for highly p-type doping and type II band alignment in large scale monolayer WSe2/Se-terminated GaAs heterojunction grown by molecular beam epitaxy.

Two-dimensional materials (2D) arranged in hybrid van der Waals (vdW) heterostructures provide a route toward the assembly of 2D and conventional III-V semiconductors. Here, we report the structural and electronic properties of single layer WSe2 grown by molecular beam epitaxy on Se-terminated GaAs(111)B. Reflection high-energy electron diffraction images exhibit sharp streaky features indicative of a high-quality WSe2 layer produced via vdW epitaxy. This is confirmed by in-plane X-ray diffraction. The single layer of WSe2 and the absence of interdiffusion at the interface are confirmed by high resolution X-ray photoemission spectroscopy and high-resolution transmission microscopy. Angle-resolved photoemission investigation revealed a well-defined WSe2 band dispersion and a high p-doping coming from the charge transfer between the WSe2 monolayer and the Se-terminated GaAs substrate. By comparing our results with local and hybrid functionals theoretical calculation, we find that the top of the valence band of the experimental heterostructure is close to the calculations for free standing single layer WSe2. Our experiments demonstrate that the proximity of the Se-terminated GaAs substrate can significantly tune the electronic properties of WSe2. The valence band maximum (VBM, located at the K point of the Brillouin zone) presents an upshift of about 0.56 eV toward the Fermi level with respect to the VBM of the WSe2 on graphene layer, which is indicative of high p-type doping and a key feature for applications in nanoelectronics and optoelectronics.

Temporal variation of heart failure hospitalization: does it exist?

Congestive heart failure (CHF) is the end stage of many cardiac diseases, and one of the leading causes of mortality and morbidity around the world. Coronary heart disease and hypertension (either singly or together) are the main etiology for CHF. It has been reported that major acute cardiovascular events (myocardial infarction, sudden death, cardiac arrest, ischemic and hemorrhagic stroke, pulmonary embolism, rupture/dissection of aortic aneurysms) do not occur randomly through time, but exhibit a specific temporal periodicity characterized by seasonal (winter), weekly (Monday), and circadian (morning) patterns of onset. Thus, because the major causes of CHF present a temporal pattern, in the past several years some studies have investigated the temporal variation of CHF hospitalization and mortality, with results indicating the possibility of a preference for winter months, Mondays, and nighttime, respectively.

Estimation of renal function in patients with eating disorders.

BACKGROUND: Renal function could be evaluated with different equations such as Cockcroft-Gault formula (C-G), Mayo Clinic Quadratic (MAYO) and four MDRD variables. Clinical application of different formulae in conditions with severe energy restriction or in obese subjects is still a matter of investigation. METHOD: Renal function of 55 anorexia nervosa (AN) and 44 bulimia nervosa (BN) patients was evaluated with C-G formula for creatinine clearance calculation, and glomerular filtration rate (GFR) was estimated with MAYO and MDRD equations. RESULTS: BN group was older and had higher weight, body mass index (BMI), body surface area than AN subjects; however, their mean BMI was in the normal range. AN group had better renal function than BN one when it was evaluated with MAYO and MDRD; on the contrary, it was worse when it was calculated with C-G. The results obtained from the three formulae were poorly correlated and Bland-Altman analysis confirmed that the results of the three formulae were not in agreement. DISCUSSION: C-G is inaccurate when it is applied to obese or cachectic subjects. MDRD underestimates renal function in normal-high GFR. MAYO seems to be a good alternative to the other equations leading to correct classification of patients; therefore, it should be used to diagnose eating disorder subjects as renal insufficient.

Risk factors for metabolic syndrome in stable Italian renal transplant patients.

BACKGROUND: The prevalence of metabolic syndrome (MS) in renal transplant recipients (RTR) is still under investigation. METHODS: We performed a cross-sectional study of 107 stable RTR who were diagnosed as having MS defined by the Adult Treatment Panel III of the National Cholesterol Education Program (NCEP-ATP III) criteria. Anthropometric, clinical and biochemical data were collected. RESULTS: Mean age of the patients studied was 55 ± 11 years (72 male, 35 female), dialysis duration before transplantation 30 ± 31 months, time since transplantation 42 ± 13 months. Mean serum creatinine was 1.68 ± 0.64 mg/dl; creatinine clearance by Cockcroft-Gault formula 53 ± 20 ml/min, glomerular filtration rate by 4-variable MDRD formula 48 ± 18 ml/min/1.73 m(2). Thirty-seven patients (34.5%) had MS. The MS patients had higher weight (76 ± 13 vs. 68 ± 12 kg, p = 0.0033), body mass index (BMI) (26 ± 4 vs. 24 ± 3 kg/m(2), p = 0.0025), waist circumference (101 ± 11 vs. 90 ± 11 cm, p < 0.0001), prevalence of BMI >25 k/m(2) (57 vs. 34%, p = 0.0254), prevalence of diabetes mellitus before transplantation (8 vs. 0%, p = 0.0157), glycaemia (104 ± 31 vs. 87 ± 11 mg/dl, p = 0.0002), and triglyceridaemia (225 ± 105 vs. 112 ± 35 mg/dl, p < 0.0001). They also showed lower levels of high-density lipoprotein cholesterol (48 ± 15 vs. 68 ± 17 mg/dl, p < 0.0001). Multiple logistic regression analysis showed that only BMI was independently associated with MS (OR 1.21, 95% CI 1.06-1.37, p = 0.0037). CONCLUSIONS: MS according to NCEP-ATP III criteria appears to be present in about one-third of RTR, and even small increases in BMI above 25 kg/m(2) may determine the presence of MS in these patients. Therefore the preventive value of lifestyle modifications is very important for such patients, in order to strictly maintain body fat accumulation within the normal range.

Evidence-based statin prescription for cardiovascular protection in renal impairment.

Dyslipidemia is a well-known risk factor for cardiovascular disease in the general population, and the cardioprotective role of statins is well established. However, although cardiovascular disease is the major cause of morbidity and mortality in chronic kidney disease (CKD), the role of statin therapy is still under investigation. In CKD the atherosclerotic burden is high and pathophysiology of dyslipidemia is complex; however, the majority of large-scale statin trials excluded patients with CKD. Statins could have different effects in the different stages of CKD. Two large trials involving haemodialysis patients showed unfavourable results, whereas in renal transplant subjects as well as in early CKD subjects, statins reduced cardiovascular risk. The studies involving early CKD patients are post-hoc analyses of large trials and they showed that statins are more effective in secondary than in primary prevention. The aim of this study was to evaluate the effectiveness of statins for prevention of cardiovascular events by calculating the number of patients needed to be treated in different interventional trials. We conclude that dyslipidemia is a modifiable cardiovascular risk and statins appear to be an effective treatment especially in the early stages of CKD. Patients on renal replacement therapy could obtain an advantage from this treatment; however, the patient's clinical prognosis should be taken into account when evaluating treatment.

Strain and Spin-Orbit Coupling Engineering in Twisted WS2/Graphene Heterobilayer.

The strain in hybrid van der Waals heterostructures, made of two distinct two-dimensional van der Waals materials, offers an interesting handle on their corresponding electronic band structure. Such strain can be engineered by changing the relative crystallographic orientation between the constitutive monolayers, notably, the angular misorientation, also known as the "twist angle". By combining angle-resolved photoemission spectroscopy with density functional theory calculations, we investigate here the band structure of the WS2/graphene heterobilayer for various twist angles. Despite the relatively weak coupling between WS2 and graphene, we demonstrate that the resulting strain quantitatively affects many electronic features of the WS2 monolayers, including the spin-orbit coupling strength. In particular, we show that the WS2 spin-orbit splitting of the valence band maximum at K can be tuned from 430 to 460 meV. Our findings open perspectives in controlling the band dispersion of van der Waals materials.

Posterior reversible encephalopathy syndrome in an 87-year-old woman with Escherichia coli bloodstream infection.

We present the case of an 87-year-old woman with history of hypertension, hypercholesterolemia, ischemic heart diseases, urinary tract infections, and cerebrovascular disease who experienced a transient clinical picture characterized by confusion, lethargy, and acute renal dysfunction in the course of urinary tract infection with Escherichia coli bacteremia. Escherichia coli bloodstream infection was associated with brain computed tomography (CT) and magnetic resonance imaging (MRI) patterns in which the lesion distribution was consistent with posterior reversible encephalopathy syndrome (PRES). Diagnosis of PRES was confirmed by demonstration of vasogenic edema on apparent diffusion coefficient (ADC) maps and near-complete resolution of clinical manifestations at discharge.