The recent discovery of the Weyl semimetal CeAlSi with simultaneous breaking of inversion and time-reversal symmetries has opened up new avenues for research into the interaction between light and ...topologically protected bands. In this work, we present a comprehensive examination of shift current and injection current responsible for the circular photogalvanic effect in CeAlSi using first-principles calculations. Our investigation identifies a significant injection current of 1.2 mA/V\(^2\) over a broad range in the near-infrared region of the electromagnetic spectrum, exceeding previously reported findings. In addition, we explored several externally controllable parameters to further enhance the photocurrent. A substantial boost in the injection current is observed when applying uniaxial strain along the \(c\)-axis of the crystal \(-\) a 5% strain results in a remarkable 64% increment. The exceptional photocurrent response in CeAlSi suggests that magnetic non-centrosymmetric Weyl semimetals may provide promising opportunities for novel photogalvanic applications.
Four-fifths of all blind or vision impaired people live in middle-income and low-income countries with the African region and parts of Asia and the Middle East bearing the heaviest burden. At the ...same time, we know that around two thirds of all blind people in the world are female. Hence, the poorest (and usually the oldest) women are most likely to have their lives limited by visual impairment. While recent strategies have focussed on international variations in eye health, very few have paid attention to the gender differences that are an inextricable element in these inequalities. This review will explore possible explanations for the advantage of men in the exercise of one of the most basic of human senses. It will show that this cannot be understood through the use of a biomedical approach alone. Broader social perspectives will also be needed in order to create an appropriate knowledge base for tackling global inequalities in blindness.
This study assesses the adsorption of Pb(II) on natural kaolin waste (KRnatural) and on that treated with 3 mol L-1 H2SO4 and HCl. Equilibrium and thermodynamic parameters were determined. The ...results indicate that the values of CEC, specific area and SiO2/Al2O3 ratio (4.6-6.0 cmol kg-1, 14.0-16.0 m² g-1 and 1.16-1.30, respectively) vary only slightly for the adsorbents; the concentration of Pb2+ is much higher than that of other species (PbOH+ and Pb(OH)2). The values of R L, ΔGº, ΔHº and ΔSº are typical of feasible, spontaneous, exothermic and ordered adsorption. The chemisorption on KRnatural is more feasible and ordered.
The essential oils obtained by hydrodistillation of two samples of fresh Mikania glauca leaves collected in different periods were analyzed by gas chromatography (GC) and by GC–mass spectrometry ...(GC–MS). Twenty compounds, representing 99% of the total oil composition, were identified and quantified in sample 1, while forty-five compounds, also representing 99% of the total oil composition, were identified in sample 2. The essential oils from the fresh leaves of both samples were rich in the terpenes. In sample 1 and 2, respectively, α-pinene (27% and 26%), β-pinene (22% and 36%), myrcene (24% and 18%), β-caryophyllene (9% and 6%) and bicyclogermacrene (8% and 4%) were the principal constituents. This demonstrated the predominance of monoterpene hydrocarbons in the essential oil of M. glauca and the influence of the collection period on the concentrations of the components.
An electrochemical biosensor based on sulfonated graphene/polyaniline nanocomposite was developed for urea analysis. Oxidative polymerization of aniline in the presence of sulfonated graphene oxide ...was carried out by electrochemical methods in an aqueous environment. The structural properties of the nanocomposite were characterized by Fourier-transform infrared, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques. The urease enzyme-immobilized sulfonated graphene/polyaniline nanocomposite film showed impressive performance in the electroanalytical detection of urea with a detection limit of 0.050 mM and a sensitivity of 0.85 (μA · cm(-2)·mM(-1). The biosensor achieved a broad linear range of detection (0.12-12.3 mM) with a notable response time of approximately 5 seconds. Moreover, the fabricated biosensor retained 81% of its initial activity (based on sensitivity) after 15 days of storage at 4°C. The ease of fabrication coupled with the low cost and good electrochemical performance of this system holds potential for the development of solid-state biosensors for urea detection.
The Au-Ag bimetallic nanostructures were synthesized independently using three different reducing agents ascorbic acid (C6H8O6), sodium borohydride (NaBH4) and tri-sodium citrate dihydrate ...(C6H9Na3O9) to understand their effect on the morphology of the nanostructures. The nanostructures obtained using the reducing agents mentioned in above order, were found in sprouted potato, cubical, and prolate spheroid (PS) shapes. All the synthesized nanostructures were characterized using energy-dispersive X-ray spectroscopy and extinction spectroscopy. The surface enhanced Raman scattering (SERS) activity of all these nanostructures was studied using Raman probe solutions with micro and nanomolar concentrations. Relatively, the PS shaped nanostructures were found to be more stable and better for SERS studies. Therefore, these nanostructures were further characterized by Transmission electron microscopy and X-ray photoelectron spectroscopy. The usefulness of PS shaped Au-Ag nanostructures was also demonstrated by recording the spectra of both methylene blue (MB) and 4-Aminothiophenol (4-ATP) solutions with femtomolar concentration. The experimental enhancement factor (EEF) was found to be around 1.1 × 1011 in case of MB solution with femtomolar concentration. The possible origin for the EEF is explained using quasi-static theory and Finite Element Method (FEM) based simulations.
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•To investigate the effect of reducing agent on the stability and shape of the Au-Ag bimetallic nanostructures, the nanostrcures have been synthesized using three different reducing agents Ascorbic acid (AA), Sodium borohydride (SB) and Tri-sodium citrate dehydrate (TC).•Nanostructures synthesized using AA, SB, and TC are found in sprouted potato, cubical, and prolate spheroid (PS) shapes, respectively.•SERS activity of the synthesized structures has been studied systematically. The PS shaped nanostructures have been found relatively stable and better for SERS studies.•The SERS detection limit is found lower than 1 fM and the experimental enhancement factor (EEF) is in the order of 1011.•The possible reasons for the EEF have been explained using quasi-static theory and Finite Element Method simulations.
Monolayer of MoSe2, having a typical direct band gap of ∼1.5 eV, is a promising material for optoelectronic and solar cell applications. When this 2D semiconductor is supported on transition metal ...substrates, such as Ni(111) and Cu(111), its electronic structure gets modulated. First principles density functional investigation shows the appearance of de-localized mid-gap states in the density of states. The work function of the semiconductor overlayer gets modified considerably, indicating n-type doping caused by the metal contacts. The charge transfer across the metal-semiconductor junction also significantly enhances the chemical reactivity of the MoSe2 overlayer, as observed by Hydrogen absorption. Furthermore, for Ni contact, there is a signature of induced magnetism in MoSe2 monolayer.
Despite two decades of research, a transcatheter atrial septal defect closure device is not available for clinical use. We have designed a new superelastic Nitinol-Dacron, double-disk, ...self-centering, atrial septal defect closure device and studied its efficacy in a canine model of atrial septal defects.
Atrial septal defects were created surgically in 20 adult dogs using either a 7.5-mm or 10-mm punch. Percutaneous transcatheter closures were attempted using a new device. The device sizes used were 20 mm in 6 dogs, 22 mm in 9, and 25 mm in 5 (22.1 +/- 1.9 mm, mean +/- SD). The stretched atrial septal defect diameter was 10.5 +/- 1.3 mm, and the device to stretched atrial septal defect diameter ratio was 2.1 +/- 0.3. Closures were successful in 19 studies and unsuccessful in 1. Angiography showed a left-to-right shunt in all 20 dogs before closure. Immediately after closure (n = 19), there were no shunts in 17 and trivial shunts in 2. Six dogs were followed for a period of 4.7 +/- 3.0 months (range, 2 to 8 months). The trivial shunt present in 1 animal immediately after closure had closed by the time of the repeat study. Spontaneous embolization of the device was not seen during follow-up. A solitary wire fracture was found 8 months after closure in 1 device. Light microscopy at 8 weeks in 3 dogs showed the devices to be covered by smooth endocardium, enmeshed in mature collagen tissue, with a minimal mononuclear cell infiltration. Retrievability was assessed by deliberately embolizing 4 devices in 2 dogs into the right atrium (n = 1) and pulmonary artery (n = 3). All devices were successfully retrieved with a snare.
This feasibility study demonstrates that this new self-centering atrial septal defect closure device has a number of design features that permit effective and safe closures in a canine model. These results support the investigation of this device in human clinical trials.
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