Explore the vast range of titles available.

Semiconductor heterostructures are the fundamental platform for many important device applications such as lasers, light-emitting diodes, solar cells, and high-electron-mobility transistors. Analogous to traditional heterostructures, layered transition metal dichalcogenide heterostructures can be designed and built by assembling individual single layers into functional multilayer structures, but in principle with atomically sharp interfaces, no interdiffusion of atoms, digitally controlled layered components, and no lattice parameter constraints. Nonetheless, the optoelectronic behavior of this new type of van der Waals (vdW) semiconductor heterostructure is unknown at the single-layer limit. Specifically, it is experimentally unknown whether the optical transitions will be spatially direct or indirect in such hetero-bilayers. Here, we investigate artificial semiconductor heterostructures built from single-layer WSe ₂ and MoS ₂. We observe a large Stokes-like shift of ∼100 meV between the photoluminescence peak and the lowest absorption peak that is consistent with a type II band alignment having spatially direct absorption but spatially indirect emission. Notably, the photoluminescence intensity of this spatially indirect transition is strong, suggesting strong interlayer coupling of charge carriers. This coupling at the hetero-interface can be readily tuned by inserting dielectric layers into the vdW gap, consisting of hexagonal BN. Consequently, the generic nature of this interlayer coupling provides a new degree of freedom in band engineering and is expected to yield a new family of semiconductor heterostructures having tunable optoelectronic properties with customized composite layers.

Optical control of magnetization using femtosecond laser without applying any external magnetic field offers the advantage of switching magnetic states at ultrashort time scales. Recently, all-optical helicity-dependent switching (AO-HDS) has drawn a significant attention for potential information and data storage device applications. In this work, we employ element and magnetization sensitive photoemission electron microscopy (PEEM) to investigate the role of heating in AO-HDS for thin films of the rare-earth transition-metal alloy TbFe. Spatially resolved measurements in a 3–5 μm sized stationary laser spot demonstrate that AO-HDS is a local phenomenon in the vicinity of thermal demagnetization in a ‘ring’ shaped region. The efficiency of AO-HDS further depends on a local temperature profile around the demagnetized region and thermally activated domain wall motion. We also demonstrate that the thickness of the film determines the preferential switching direction for a particular helicity.

Semiconductor heterostructures are the fundamental platform for many important device applications such as lasers, light-emitting diodes, solar cells and high-electron-mobility transistors. Analogous to traditional heterostructures, layered transition metal dichalcogenide (TMDC) heterostructures can be designed and built by assembling individual single-layers into functional multilayer structures, but in principle with atomically sharp interfaces, no interdiffusion of atoms, digitally controlled layered components and no lattice parameter constraints. Nonetheless, the optoelectronic behavior of this new type of van der Waals (vdW) semiconductor heterostructure is unknown at the single-layer limit. Specifically, it is experimentally unknown whether the optical transitions will be spatially direct or indirect in such hetero-bilayers. Here, we investigate artificial semiconductor heterostructures built from single layer WSe2 and MoS2 building blocks. We observe a large Stokes-like shift of ~100 meV between the photoluminescence peak and the lowest absorption peak that is consistent with a type II band alignment with spatially direct absorption but spatially indirect emission. Notably, the photoluminescence intensity of this spatially indirect transition is strong, suggesting strong interlayer coupling of charge carriers. The coupling at the hetero-interface can be readily tuned by inserting hexagonal BN (h-BN) dielectric layers into the vdW gap. The generic nature of this interlayer coupling consequently provides a new degree of freedom in band engineering and is expected to yield a new family of semiconductor heterostructures having tunable optoelectronic properties with customized composite layers.

Ferroic materials (ferromagnetic, ferroelectric, ferroelastic) usually divide into domains with different orientations of their order parameter. Coupling different ferroic systems creates new functionalities, for instance the electrical control of macroscopic magnetic properties including magnetization and coercive field. Here we show that ferroelastic domains can be used to control both magnetic order and magnetization direction at the nanoscale with a voltage. We use element-specific x-ray imaging to map the magnetic domains as a function of temperature and voltage in epitaxial FeRh on ferroelastic BaTiO3. Exploiting the nanoscale phase-separation of FeRh, we locally interconvert between ferromagnetism and antiferromagnetism with a small electric field just above room temperature. Our results emphasize the importance of nanoscale ferroic domain structure to achieve enhanced coupling in artificial multiferroics.

Implementation of antiferromagnetic compounds as active elements in spintronics has been hindered by their insensitive nature against external perturbations which causes difficulties in switching among different antiferromagnetic spin configurations. Electrically-controllable strain gradient can become a key parameter to tune the antiferromagnetic states of multiferroic materials. We have discovered a correlation between an electrically-written straight-stripe mixed-phase boundary and an in-plane antiferromagnetic spin axis in highly-elongated La-5%-doped BiFeO\\(_{3}\\) thin films by performing polarization-dependent photoemission electron microscopy in conjunction with cluster model calculations. Model Hamiltonian calculation for the single-ion anisotropy including the spin-orbit interaction has been performed to figure out the physical origin of the link between the strain gradient present in the mixed phase area and its antiferromagnetic spin axis. Our findings enable estimation of the strain-gradient-induced magnetic anisotropy energy per Fe ion at around 5\\(\\times\\)10\\(^{-12}\\) eV m, and provide a new pathway towards an electric-field-induced 90\\(^{\\circ}\\) rotation of antiferromagnetic spin axis at room temperature by flexomagnetism.

Diffractive optical elements (DOEs) are increasingly used in electro-optical systems due to their design flexibility, which offers advantages over refractive optics. Although determining the point spread function (PSF) is straightforward when the plane wave is parallel to the surface normal of DOE, a comprehensive method is needed for the plane waves with an angle of incidence. Therefore, this paper proposes a general approach in order to determine the PSF under non-normal illumination of plane waves. Although the numerical PSF is specifically proposed for the Fresnel zone plate (FZP) diffractive lens, the method is adaptable to any DOE. The simulation results were validated against the Zemax optical design software for angular incidences ranging from − 60° to + 60⁰, and the results were shared. Additionally, the paraxial approximation of the PSF was proposed and verified using ZEMAX for angular incidences between −10° and + 10°. Finally, a simplified approximation for the Fresnel number, applicable to FZPs was proposed. Consequently, this research presents a novel method that can be applied to all types of DOEs for determining the numerical PSF non-normal illumination of plane waves. The proposed approach also allows for the calculation of the modulation transfer function (MTF) for diffractive optical elements in such scenarios. By incorporating the angle of incidence into PSF analysis, this work makes a significant advancement in the field of diffractive optics.

Global warming has become the center of worldwide environmental concerns, especially in recent years. One of the ways to deal with global warming that causes climate change is to adopt the renewable energy power technique. Different renewable energy sources such as solar, wind, hydro, ocean, geothermal, and bioenergy are currently the backbone of green and sustainable economic growth. However, renewable energy sites are directly or indirectly dependent on environmental, social, and technical criteria.The main objective of this paper is to identify potential best renewable energy site alternatives using the maximum entropy model (MaxEnt) and Geographical Information systems (GIS). Thus, the framework formed by the findings will guide investors in the renewable energy sector. The results showed that suitable areas for solar and wind were mainly located in the Hatay and Mersin of the Eastern Mediterranean Region in Turkey. The energy suitability site maps indicate that 8% (3.42 km 2 ) and 3.39% (1554 km 2 ) of the total study area have suitability and very suitability for solar and wind energy respectively. Moreover, it is seen that 44.82% (20,689km 2 ) of the regions are the same when suitable and very suitable regions are overlaid for the installation of solar and wind energy sites. The receiver operating characteristic (ROC) curve was used to evaluate model performance. The area under the curve (AUC) values are calculated 0.87 and 0.95 for solar and wind energy, respectively. Relying on realistic data, this paper proposes an innovative method to identify suitable areas for solar and wind power plants. The maps obtained to contribute to renewable energy production will be useful for creating future strategies in the Mediterranean region.

Background Hypocholesterolemia is the most frequently encountered lipid abnormality in sickle cell disease (SCD). We enrolled pediatric patients to determine the relationships between lipid profile and parameters of hemolysis, oxidative stress and chronic inflammation in SCD. Methods The study involved 35 pediatric SCD patients and 19 healthy controls. Patients were crisis-free and had not received transfusions for the last 3 months. Total cholesterol, triglyceride, HDL-C, LDL-C, VLDL-C, apolipoprotein A1, apolipoprotein B, LCAT, LDH, bilirubin, haptoglobin, iron, ferritin, hemin, serum amyloid A (SAA), myeloperoxidase (MPO), uric acid, ALT and GGT levels were evaluated in patients’ blood. Results Patients had hypocholesterolemia depicted by lower levels of total cholesterol, HDL-C, LDL-C, as well as Apolipoprotein A1 and Apolipoprotein B compared to controls. The chronic hemolysis of SCD was evident in patients by higher LDH and bilirubin and almost undetectable haptoglobin levels. Hemin levels (as a measure of oxidized heme) were significantly increased in patients with SCD. Inflammation markers, SAA and MPO, were significantly increased in the patients as well. There were negative correlations between HDL-C and LDH, and Apo A1 and SAA. Hemin was positively correlated to MPO. Conclusion Hemolysis was associated with decreased HDL –C, and Inflammation was linked to decreased apolipoprotein A1 levels in our SCD patients. Therefore, we suggest that the HDL particle is altered during the course of the disease. The altered HDL in SCD may become dysfunctional and result with a slowing down of the reverse cholesterol transport.

Purpose This study aimed to evaluate clinical pharmacist’s contribution to the pneumococcal vaccination rate by providing education to cancer patients in hospital settings. Methods This study was conducted in 2 tertiary-care hospitals’ medical oncology outpatient clinics. Patients over 18 years of age and diagnosed with cancer for less than 2 years, in remission stage, and have not previously received the pneumococcal vaccine were included. Patients were randomized to intervention and control groups. The intervention group was provided vaccination education and recommended to receive the PCV13 vaccine. The control group received routine care. Patients’ knowledge about pneumonia/pneumococcal vaccine, Vaccine Attitude Examination Scale (VAX) score, and vaccination rates were evaluated at baseline and 3 months after the education. Results A total of 235 patients (intervention: 117, control: 118) were included. The mean age ± SD was 57.86 ± 11.88 years in the control and 60.68 ± 11.18 years in the intervention groups. The numbers of correct answers about pneumonia/pneumococcal vaccine ( p  = 0.482) and VAX scores ( p  = 0.244) of the groups were similar at baseline. After the intervention, the median (IQR) number of correct answers in intervention group [10(3)] was higher than control group [8(4)] ( p  < 0.001). After the education, the total VAX score (mean ± SD) was less in intervention group (33.09 ± 7.018) than the control group (36.07 ± 6.548) ( p  = 0.007). Three months after the education, 20.2% of the patients in the intervention and 6.1% in the control groups were vaccinated with pneumococcal vaccine ( p  = 0.003). Conclusions The pneumococcal vaccination rate in cancer patients has increased significantly by the education provided by a clinical pharmacist in hospital settings.

PurposeTo assess the use of virtual monochromatic images (VMI) for discrimination of affected and non-affected bowel walls in patients with Crohn’s disease (CD) as well as to compare mural enhancement between patients with and without CD.Materials and methodsThis retrospective study included 61 patients (47 with CD, 14 without CD). Attenuation value (AV), signal-to noise ratio (SNR), and contrast-to-noise ratio (CNR) were obtained at VMI energy levels from 40 to 110 keV in 10 keV increment. Analyses were performed among affected and non-affected bowel walls in CD patients, as well as from bowel walls in patients without CD. Image quality and mural enhancement were evaluated at VMI energy levels at 40, 70, and 110 keV.ResultsAt all energy levels of VMI, each quantitative data for AV, SNR, and CNR showed statistically significant difference between diseased and non-diseased bowel walls in CD patients. In the quantitative assessment of patients with and without CD, the optimal AV and SNR were obtained at 40 keV, and the optimal CNR was obtained at 70 keV. For the qualitative assessment, the best image quality and mural enhancement were obtained at 70 keV and 40 keV, respectively.ConclusionVMI are helpful for the differentiation of affected bowel walls in CD patients, providing high diagnostic accuracy.