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We report on the fabrication of a novel design of GaAs/(In,Ga)As/GaAs radial nanowire heterostructures on a Si 111 substrate, where, for the first time, the growth of inhomogeneous shells on a lattice mismatched core results in straight nanowires instead of bent. Nanowire bending caused by axial tensile strain induced by the (In,Ga)As shell on the GaAs core is reversed by axial compressive strain caused by the GaAs outer shell on the (In,Ga)As shell. Progressive nanowire bending and reverse bending in addition to the axial strain evolution during the two processes are accessed by in situ by x-ray diffraction. The diameter of the core, thicknesses of the shells, as well as the indium concentration and distribution within the (In,Ga)As quantum well are revealed by 2D energy dispersive x-ray spectroscopy using a transmission electron microscope. Shell(s) growth on one side of the core without substrate rotation results in planar-like radial heterostructures in the form of free standing straight nanowires. [ABSTRACT FROM AUTHOR]

Background: Celiac serology can be transiently elevated in patients with type 1 diabetes mellitus (T1DM) and normalized despite gluten consumption. This study aimed to identify the frequency and predictive factors of spontaneous normalization of anti-tissue transglutaminase (anti-TTG-IgA) antibodies in these patients. Methods: The charts of all patients (≤18 years) with T1DM were retrospectively reviewed from 2012 to 2021 at a tertiary care center in Riyadh, Saudi Arabia. The following data were collected: clinical characteristics of the participants, anti-TTG-IgA-immunoglobulin (Ig) A antibody, and histological findings. The outcome of positive anti-TTG-IgA-IgA in patients with T1DM and the predictive factors for spontaneous normalization were investigated. Results: Of the 1,006 patients with T1DM, 138 (13.7%) had elevated anti-TTG-IgA antibodies, celiac disease was diagnosed in 58/138 (42%) patients, spontaneous normalization of anti-TTG-IgA was observed in 65 (47.1%) patients, and fluctuating anti-TTG-IgA antibodies were seen in 15 (10.9%) patients. The patients with anti-TTG-IgA levels at 3–10 times the upper normal limits (UNL), and those with levels ≥10 times UNL were less likely to have spontaneous normalization of anti-TTG-IgA compared to patients with levels at 1–3 times UNL (hazard ratio [HR] = 0.28, 95% confidence interval [Cl] = 0.13–0.61, P = 0.001, and HR = 0.03, 95% Cl = 0.00–0.19, P < 0.001, respectively). Conclusion: Asymptomatic patients with T1DM with mild elevation of anti-TTG-IgA need not be rushed for invasive endoscopy or exposed to an un-needed gluten-free diet but should rather have a regular follow-up of their celiac serology. [ABSTRACT FROM AUTHOR]

This paper addresses the heat and species transfer in a composite cavity linked with a horizontal channel. The cavity comprises a triangular porous layer and one of its vertical sides is exposed to a high temperature and concentration. The mathematical conservation equations are solved numerically using the Galerkin finite element method. The ranges of Reynolds and Richardson numbers are taken to ascertain laminar flow, Re = 50–250 and Ri = 0.1–100. The size of the porous layer is quantified by the thickness of the porous layer Hp = 0.25–1. The problem is studied for two cases of heat and species sources; the opposing case, when the active side is on the right, and assisting case, when the active side is on the left. Results reveal that for specified conditions, the triangular porous layer increases Nusselt and Sherwood numbers by 30% and 32%, respectively, more than the horizontal porous layer. The opposing case gives maximum convective heat transfer, where for Ri = 0.01, the Nusselt number is higher by 61% and 134% for Re = 50 and 250, respectively, while for Ri = 100, the percentages increase are 67% and 43%. [ABSTRACT FROM AUTHOR]

Nanoprobe X‐ray diffraction (nXRD) using focused synchrotron radiation is a powerful technique to study the structural properties of individual semiconductor nanowires. However, when performing the experiment under ambient conditions, the required high X‐ray dose and prolonged exposure times can lead to radiation damage. To unveil the origin of radiation damage, a comparison is made of nXRD experiments carried out on individual semiconductor nanowires in their as‐grown geometry both under ambient conditions and under He atmosphere at the microfocus station of the P08 beamline at the third‐generation source PETRA III. Using an incident X‐ray beam energy of 9 keV and photon flux of 1010 s−1, the axial lattice parameter and tilt of individual GaAs/In0.2Ga0.8As/GaAs core–shell nanowires were monitored by continuously recording reciprocal‐space maps of the 111 Bragg reflection at a fixed spatial position over several hours. In addition, the emission properties of the (In,Ga)As quantum well, the atomic composition of the exposed nanowires and the nanowire morphology were studied by cathodoluminescence spectroscopy, energy‐dispersive X‐ray spectroscopy and scanning electron microscopy, respectively, both prior to and after nXRD exposure. Nanowires exposed under ambient conditions show severe optical and morphological damage, which was reduced for nanowires exposed under He atmosphere. The observed damage can be largely attributed to an oxidation process from X‐ray‐induced ozone reactions in air. Due to the lower heat‐transfer coefficient compared with GaAs, this oxide shell limits the heat transfer through the nanowire side facets, which is considered as the main channel of heat dissipation for nanowires in the as‐grown geometry. [ABSTRACT FROM AUTHOR]

Typically, core–shell–shell semiconductor nanowires (NWs) made from III–V materials with low lattice mismatch grow pseudomorphically along the growth axis, i.e. the axial lattice parameters of the core and shell materials are the same. Therefore, both the structural composition and interface strain of the NWs are encoded along directions perpendicular to the growth axis. Owing to fluctuations in the supplied growth species during molecular beam epitaxy (MBE) growth, structural parameters such as local shell thickness, composition and strain may differ between NWs grown onto the same substrate. This requires structural analysis of single NWs instead of measuring NW ensembles. In this work, the complete structure of single GaAs/(In,Ga)As/GaAs core–shell–shell NW heterostructures is determined by means of X‐ray nanodiffraction using synchrotron radiation. The NWs were grown by MBE on a prepatterned silicon (111) substrate with a core diameter of 50 nm and an (In,Ga)As shell thickness of 20 nm with a nominal indium concentration of 15%, capped by a 30 nm GaAs outer shell. In order to access single NWs with the X‐ray nanobeam being incident parallel to the surface of the substrate, a single row of holes with a separation of 10 µm was defined by electron‐beam lithography to act as nucleation centres for MBE NW growth. These well separated NWs were probed sequentially by X‐ray nanodiffraction, recording three‐dimensional reciprocal‐space maps of Bragg reflections with scattering vectors parallel (out‐of‐plane) and perpendicular (in‐plane) to the NW growth axis. From the out‐of‐plane 111 Bragg reflection, deviations from hexagonal symmetry were derived, together with the diameters of probed NWs grown under the same conditions. The radial NW composition and interface strain became accessible when measuring the two‐dimensional scattering intensity distributions of the in‐plane and reflections, exhibiting well pronounced thickness fringes perpendicular to the NW side planes (truncation rods, TRs). Quantitative values of thickness, composition and strain acting on the (In,Ga)As and GaAs shells were obtained via finite‐element modelling of the core–shell–shell NWs and subsequent Fourier transform, simulating the TRs measured along the three different directions of the hexagonally shaped NWs simultaneously. Considering the experimental constraints of the current experiment, thicknesses and In content have been evaluated with uncertainties of ±2 nm and ±0.01, respectively. Comparing data taken from different single NWs, the shell thicknesses differ from one to another. [ABSTRACT FROM AUTHOR]

Abstract: Cerebral vasospasm secondary to subarachnoid hemorrhage leads to increased cerebrovascular resistance and may cause ischemia in the affected vascular territories. The currently available therapeutic options for treating vasospasm are limited. The effect of ethanol at a concentration of 0.75g/kg body weight on blood flow velocity in the major cerebral arteries was studied. In 31 healthy persons, the major extra- and intracranial cerebral vessels were examined by Doppler ultrasonography before and following oral ingestion of 0.75g/kg body weight of ethanol. An additional 20 healthy subjects served as a control group. Ethanol in the applied concentration significantly increased the systolic, diastolic, and mean blood flow velocities and significantly decreased the pulsatility indices in the middle cerebral artery (MCA). It may reduce vascular resistance and may increase cerebral blood flow in the area supplied by the MCA in healthy persons. [Copyright &y& Elsevier]

Aims - The objective of our study is to compare pharmaco-invasive strategy (PhIS) in terms of safety and efficacy, with primary percutaneous coronary intervention (pPCI) strategy as standard therapy for STEMI patients from remote areas. Background - At present, primary percutaneous coronary intervention (pPCI) is the preferred reperfusion strategy for STEMI patients. However, despite pPCI being the gold standard, it is not always achievable due to variables such as lack of cardiac catheterization services and delays in the first medical contact-to-balloon time. Methods - This observational study is based on a prospective analysis of a cohort of 157 patients with ST-elevation myocardial infarction, over nine months, at Elias University Hospital (EUH). The study assessed the safety and efficacy of a sequence of fibrinolytic therapy in the first contact hospital before being referred to our center for PCI (PhIS, 35 patients, 22.29%) versus angioplasty alone (pPCI, 122 patients, 77.70%) during hospitalization. The primary outcomes studied were in-hospital death, and major adverse cardiac events (MACE), while secondary outcomes were the length of in-hospital stay, and the safety of the procedure. Results - The median reperfusion time was lower for the PhIS group compared to the primary PCI group (4 hours, IQR:6.25 vs 7 hours, IQR:12.38, p<0.05). The left ventricular systolic function (%) on arrival at EUH was higher in the PhIS group compared with the PCI alone group (46.55; 95%CI 42.42-49.15 vs 41.73; 95%CI 39.91-43.34; p=0.04). The mean number of diseased vessels, including the culprit-lesion, were similar in the two groups (2.84 vs 2.82, p=0.09). The in-hospital mortality rate was lower in the PhIS group than in the primary PCI group (1 patient; 2.9% vs 18 patients; 14.80%; p=0.05), while the number of in-hospital major adverse cardiac events (MACE) was not significantly different (17.10% vs 26.20%; p=0.27). There was no difference of the median length of hospitalization (6 days, IQR:2 vs 5 days, IQR:3; p=0.67) for the PhIS, and primary PCI groups, respectively. The safety endpoints of the procedures were similar in the two groups. Conclusions - Pharmaco-invasive strategy (PhIS) had clinical and procedural outcomes (in-hospital MACE, length of in-hospital stay) similar to primary percutaneous coronary intervention (pPCI), in case of long distances to catheterization laboratories. Efficient thrombolysis makes PhIS a viable alternative in saving lives with a lower rate of in-hospital death than pPCI. Performed thrombolysis in a local non-PCI center and referral of the STEMI patients to a 24/7 catheterization laboratory may be a good option for areas where the infrastructure of such facilities is weak. [ABSTRACT FROM AUTHOR]

Coherent X-ray diffraction was used to measure the type, quantity and the relative distances between stacking faults along the growth direction of two individual wurtzite GaAs nanowires grown by metalorganic vapour epitaxy. The presented approach is based on the general property of the Patterson function, which is the autocorrelation of the electron density as well as the Fourier transformation of the diffracted intensity distribution of an object. Partial Patterson functions were extracted from the diffracted intensity measured along the direction in the vicinity of the wurtzite Bragg peak. The maxima of the Patterson function encode both the distances between the fault planes and the type of the fault planes with the sensitivity of a single atomic bilayer. The positions of the fault planes are deduced from the positions and shapes of the maxima of the Patterson function and they are in excellent agreement with the positions found with transmission electron microscopy of the same nanowire. [ABSTRACT FROM AUTHOR]

Coherent X-ray diffraction imaging at symmetric hhh Bragg reflections was used to resolve the structure of GaAs/In0.15Ga0.85As/GaAs core-shell-shell nanowires grown on a silicon (111) substrate. Diffraction amplitudes in the vicinity of GaAs 111 and GaAs 333 reflections were used to reconstruct the lost phase information. It is demonstrated that the structure of the core-shell-shell nanowire can be identified by means of phase contrast. Interestingly, it is found that both scattered intensity in the (111) plane and the reconstructed scattering phase show an additional threefold symmetry superimposed with the shape function of the investigated hexagonal nanowires. In order to find the origin of this threefold symmetry, elasticity calculations were performed using the finite element method and subsequent kinematic diffraction simulations. These suggest that a non-hexagonal (In,Ga)As shell covering the hexagonal GaAs core might be responsible for the observation. [ABSTRACT FROM AUTHOR]