Explore the vast range of titles available.

Microwave Limb Sounder (MLS) observations showed an obvious variation of ozone concentration during the annular solar eclipse on 21 June 2020 in the mesosphere and upper stratosphere. Ozone concentration slightly reduced near 40 km in the regions of 24°N–36°N, and increased in low latitudes at 40 km. In the heights of 45–60 km, the increase in ozone concentration in most of the regions was obvious. The ozone increases and decreases were more obvious between 60–65 km, where enhancement took the leading role. The nighttime ozone variation was weaker than the daytime in most of the heights of 30–65 km. The variation of HO2 and CO is investigated to study the photochemical and dynamical causes of ozone variation. As HO2 decreased at 1 hPa and increased at 60–65 km, ozone variation shows a mostly reversed relationship to HO2 variation. CO increased at 32–39 km and decreased at 52–60 km, which was related to the upwelling at these heights. The dynamic processes also contributed to the decrease in ozone concentration at 40 km and increase at 50–60 km.

Using the temperature data observed from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER), we investigate the response of the mesosphere and lower thermosphere (MLT) to two medium geomagnetic storms with disparate durations, on 20 April 2018 and 10 April 2022. The high-latitude MLT temperature increase in the Southern hemisphere can reach 40 K during April 2018 geomagnetic storm with a longer duration (Kp values greater than 4 for 15 h), while the temperature variations are less than 10 K for the April 2022 event (Kp values greater than 4 for 6 h). To investigate the different temperature responses to disparate geomagnetic storm durations and understand what physical process results in this difference, we simulated the two events using the thermosphere ionosphere mesosphere electrodynamics general circulation model (TIMEGCM). The simulations show that more particles and energy input in longer-duration geomagnetic storms produce larger ion drag force and pressure gradient force at ~130 km, and then the enhanced two forces cause faster horizontal wind, leading to larger horizontal divergence. Subsequently, the stronger downward vertical wind is transported to the MLT region (below 110 km) and ultimately makes greater temperature increases through adiabatic heating/cooling and vertical advection. Therefore, the effects of the storm’s duration on the MLT temperature are also important.

The impact of the annual solar eclipse, starting on 21st June 2020, attributable to surface ozone concentration (O 3 ) has been investigated in this study. To estimate the influence of the solar eclipse on O 3 better, the variations of one reaction precursor of ozone production [nitrogen dioxide (NO 2 )], coupled with the meteorological factors (including Total Solar Irradiance (TSI), Temperature (T), and Relative Humidity (RH)), were analyzed in Yunnan Province, China. The results show observed O 3 decreases from the beginning of the eclipse, reaching its minimum value when the eclipse left Yunnan province. During the period of the solar eclipse, the O 3 decrease lasted for 20 h with a reduction of more than 40%. The reduction of TSI lasted for 5 h with a maximum at -90%. Simultaneously, the temperature decreased but the relative humidity increased during the reduction in solar radiation. O 3 exhibits a significantly positive correlation with temperature and a negative correlation with relative humidity. However, NO 2 did not show a clear response with changes lasting for 4 h. O 3 and NO 2 show a negative correlation. The influence of CO on O 3 is minor except for Kunming. Thus, O 3 in seriously polluted cities is more sensitive to NO 2 and CO during the eclipse, such as in Kunming.

Focusing on the singularities of a spacecraft using control moment gyros （CMGs） to do the large angle maneuvers, a new mixture steering law is proposed to avoid the singularities. According to this method, if the CMGs are far away from the singular- ity, the Moore-Penrose pseudo-inverse steering law （MP） is used directly. If the CMGs are close to the singularity, instead of solving the inverse matrix, a set of optimal gimbal angles are sought for the singular measurement to reach the maximum, which can avoid the singularities. Simulations show that the designed steering law enables the spacecraft to carry out the large angle maneuver and avoid the singularities simultaneously.

Metal borides/borates have been considered promising as oxygen evolution reaction catalysts; however, to date, there is a dearth of evidence of long-term stability at practical current densities. Here we report a phase composition modulation approach to fabricate effective borides/borates-based catalysts. We find that metal borides in-situ formed metal borates are responsible for their high activity. This knowledge prompts us to synthesize NiFe-Boride, and to use it as a templating precursor to form an active NiFe-Borate catalyst. This boride-derived oxide catalyzes oxygen evolution with an overpotential of 167 mV at 10 mA/cm 2 in 1 M KOH electrolyte and requires a record-low overpotential of 460 mV to maintain water splitting performance for over 400 h at current density of 1 A/cm 2 . We couple the catalyst with CO reduction in an alkaline membrane electrode assembly electrolyser, reporting stable C 2 H 4 electrosynthesis at current density 200 mA/cm 2 for over 80 h. Metal borides/borates are promising candidates to become high-performance alkaline oxygen evolution reaction catalysts. This study reports an in-situ phase composition modulation approach to fabricate boride/borate-based catalysts.

To develop a high throughput colorimetric biosensor for detection of Staphylococcus aureus (SA) based on specific aptamer and catalysis of dsDNA-SYBR Green I (SG I) complex. SA specific aptamer was immobilized on a 96-well plate by hybridization with the capture probe anchored on the plate surface through streptavidin-biotin binding. In presence of SA, the aptamer was dissociated from the capture probe-aptamer duplex due to the stronger interaction between the aptamer and SA. The consequent single-strand capture probe could be hybridized with a three-way junction (TWJ) probe. With the presence of SG I, the dsDNA-SG I complex catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) under photo-irradiation, producing sensitive photo-catalyzed colorimetric response to SA. Under the optimal conditions, the proposed method could directly detect SA with the limit of detection (LOD) at 81 CFU mL −1 in PBS buffer in 5.5 hours, which demonstrated the sensitive and fast quantification of target pathogenic bacteria. The method showed weak colorimetric signal to Escherichia coli and Pseudomonas aeruginosa , indicating the high specificity for SA. In addition, the method can simultaneously detect 96 samples which can be used for high throughput analysis. The designed method may become a powerful tool for pathogenic microorganisms screening in clinical diagnostics, food safety and environmental monitoring.

Two-dimensional (2D) materials with inherent magnetism have attracted considerable attention in the fields of spintronics and condensed matter physics. The anomalous Hall effect (AHE) offers a theoretical foundation for understanding the origins of 2D ferromagnetism (2D-FM) and offers a valuable opportunity for applications in topological electronics. Here, we present uniform and large-size 2D Cr7Te8 nanosheets with varying thicknesses grown using the chemical vapor deposition (CVD) method. The 2D Cr7Te8 nanosheets with robust perpendicular magnetic anisotropy, even a few layers deep, exhibit a Curie temperature (TC) ranging from 180 to 270 K according to the varying thickness of Cr7Te8. Moreover, we observed a temperature-induced reversal in the sign of the anomalous Hall resistance, correlating with changes in the intrinsic Berry curvature. Additionally, the topological Hall effect (THE) observed at low temperatures suggests the presence of non-trivial spin chirality. Our findings about topologically non-trivial magnetic spin states in 2D ferromagnets provide a promising opportunity for new designs in magnetic memory spintronics.

Transition metal phosphides (TMPs) have exhibited decent performance in an oxygen evolution reaction (OER), which is a kinetic bottleneck in many energy storages and conversion systems. Most reported catalysts are composed of three or fewer metallic components. The inherent complexity of multicomponent TMPs with more than four metallic components hinders their investigation in rationally designing the structure and, more importantly, comprehending the component-activity correlation. Through hydrothermal growth and subsequent phosphorization, we reported a facile strategy for combining TMPs with tunable elemental compositions (Ni, Fe, Mn, Co, Cu) on a two-dimensional titanium carbide (MXene) flake. The obtained TMPs/MXene hybrid nanostructures demonstrate homogeneously distributed elements. They exhibit high electrical conductivity and strong interfacial interaction, resulting in an accelerated reaction kinetics and long-term stability. The results of different component catalysts’ OER performance show that NiFeMnCoP/MXene is the most active catalyst, with a low overpotential of 240 mV at 10 mA·cm −2 , a small Tafel slope of 41.43 mV·dec −1 , and a robust long-term electrochemical stability. According to the electrocatalytic mechanism investigation, the enhanced NiFeMnCoP/MXene OER performance is due to the strong synergistic effect of the multi-elemental composition. Our work, therefore, provides a scalable synthesis route for multi-elemental TMPs and a valuable guideline for efficient MXene-supported catalysts design.

CdS is a promising photocatalyst for solar-driven hydrogen production due to its favorable optical properties and electronic structure. However, rapid recombination of photogenerated carriers and photocorrosion significantly limit its practical application. In this study, we developed a sustainable strategy by constructing CdS/ReS2 nanocomposites through hydrothermal interfacial engineering. On this basis, ReS2 nanosheets were intercalated on the surface of CdS by the hydrothermal method for catalyst modification. The introduction of ReS2 can effectively enhance the photoelectrochemical performance of CdS and accelerate the transfer of photogenerated carriers. The effects of different ReS2 loadings on the photocatalytic activity of CdS were explored experimentally, and the data revealed that the photocatalytic hydrogen evolution efficiency reached 50 mmol g−1 h−1 when the loading amount of ReS2 was 7 wt% and did not show any obvious attenuation during four cycles. This study provides a robust surface engineering strategy to enhance the catalytic efficiency of CdS photocatalysts and provides a theoretical basis for its application in photocatalytic hydrogen precipitation. This study also emphasizes the potential of abundant, non-precious metal materials for promoting scalable, environmentally friendly hydrogen production technologies that align with the principles of green chemistry and sustainable energy systems.

Conventional magnetic resonance imaging (MRI) exhibits notable limitations in the diagnosis, grading, and therapeutic assessment of gliomas, making it insufficient to meet the demands of precision medicine. As a chemical exchange saturation transfer MRI technique, amide proton transfer (APT) imaging enables molecular-level visualization by detecting the chemical exchange of amide protons in endogenous mobile proteins and peptides. Previous studies have demonstrated that APT imaging provides substantial advantages over conventional MRI in the diagnosis, grading, and treatment monitoring of gliomas. This review systematically summarizes the development of APT imaging technology, emphasizing its innovative clinical applications, including preoperative grading, differentiation of postoperative recurrence, and dynamic evaluation of radiotherapy and chemotherapy efficacy. Furthermore, it discusses current challenges and future directions for clinical implementation, aiming to offer new perspectives for advancing precision medicine in glioma management.