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Heat treatment processes play a pivotal role in optimizing the microstructure and mechanical properties of Mg-Li alloys, thereby enhancing their performance and expanding their potential applications in structural and lightweight engineering fields. In this study, the influence of solution and aging treatments on the microstructure, phase transformation, and microhardness of friction-stir-processed (FSPed) LAZ931 Mg-Li alloy was investigated to obtain the optimal solution treatment temperature and time. An optimal solution treatment at 460 °C for 0.5 h under an Ar gas atmosphere facilitated complete α-phase dissolution with subsequent aging at 125 °C, triggering precipitation-mediated hardening. An X-ray diffraction (XRD) analysis identified a new MgLi2Al phase in the stirring zone (SZ) in addition to the α, β, and AlLi phases. Aging kinetics at 125 °C showed that SZ hardness increased to 110.5 HV after solution treatment, which was 5.3% higher than the base metal (BM). After 3 h of aging, microhardness peaked at 86.5 HV before decreasing due to the decomposition of the metastable MgLi2Al phase into the stable AlLi phase. The microhardness stabilized at around 78 HV, which was 16.2% higher than that of the original SZ. These experimental results provide a fundamental understanding of property structure for meeting the growing demand for lightweight materials and improving material properties.

Land cover land use (LCLU) products provide essential information for numerous environmental and human studies. Here, we assess the accuracy of eleven global and regional products over the conterminous U.S. using 25,000 high-confidence randomly distributed samples. Results show that in general, the National Land Cover Database (NLCD) and the Land Change Monitoring, Assessment and Projection (LCMAP) outperform other multi-class products, both in terms of higher individual class accuracy and with accuracy variability across classes. More specifically, F1 accuracy comparisons between the best performing USGS and non-USGS products indicate: (i) similar performance for the water class, (ii) USGS product outperformance in the developed (+1.3%), grass/shrub (+3.2%) and tree cover (+4.2%) classes, and (iii) non-USGS product (WorldCover) gains in the cropland (+5.1%) class. The NLCD and LCMAP also outperformed specialized single-class products, such as the Hansen Global Forest Change, the Cropland Data Layer and the Global Artificial Impervious Areas, while offering comparable results to the Global Surface Water Dynamics product. Spatial visualizations also allowed accuracy comparisons across different geographic areas. In general, the NLCD and LCMAP have disagreements mainly in the middle and southeastern part of conterminous U.S. while Esri, WorldCover and Dynamic World have most errors in the western U.S. Comparisons were also undertaken on a subset of the reference data, called spatial edge samples, that identifies samples surrounded by neighboring samples of different class labels, thus excluding easy-to-classify homogenous areas. There, the WorldCover product offers higher accuracies for the highly dynamic grass/shrub (+4.4%) and cropland (+8.1%) classes when compared to the NLCD and LCMAP products. An important conclusion while looking at these challenging samples is that except for the tree class (78%), the best performing products per class range in accuracy between 55% and 70%, which suggests that there is substantial room for improvement.

Pancreatic resection is a critical treatment for pancreatic cancer and other pancreatic diseases. Somatostatin analogs are commonly used to prevent complications following pancreatic resection, but their efficacy and safety remain debated. Following PRISMA guidelines, a systematic search was conducted across multiple databases, including PubMed, EMBASE, Scopus, Cochrane Library, Ovid, ClinicalTrials.gov, Web of Science, CNKI, and WanFang Data. The search focused on studies comparing the use of somatostatin analogs after pancreatic surgery. Key outcomes included postoperative pancreatic fistula (POPF), clinically relevant POPF (CR-POPF), mortality, and morbidity. Statistical analysis was performed using a consistency model, calculating relative risk ratios (RR) with 95% confidence intervals (CI), and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool was used to assess the quality of evidence. In the absence of stratification based on the surgical procedure, For POPF prevention, pasireotide showed a relative risk (RR) of 0.46 (95% CI: 0.23, 0.87, Low) compared to placebo, and octreotide had an RR of 0.76 (95% CI: 0.66, 0.88, Moderate). Somatostatin and vapreotide showed no significant differences. In preventing CR-POPF, pasireotide had an RR of 0.46 (95% CI: 0.23, 0.86, Low), somatostatin had an RR of 0.60 (95% CI: 0.36, 0.99, Moderate), and octreotide had an RR of 0.61 (95% CI: 0.39, 0.94, Moderate). Regarding postoperative mortality, vapreotide showed an RR of 0 (95% CI: 0.00, 0.29, Low), while octreotide, somatostatin and pasireotide did not demonstrate significant effects. For reducing morbidity, octreotide had an RR of 0.74 (95% CI: 0.66, 0.82, Moderate), somatostatin had an RR of 0.76 (95% CI: 0.66, 0.87, Moderate), vapreotide and pasireotide showed no significant effect.In Pancreaticoduodenectomy subgroup, somatostatin showed an RR of 0.22(95% CI: 0.03, 0.84, Moderate) for preventing CR-POPF.For all the other outcomes, neither somatostatin nor octreotide proved effective. While robust evidence confirms the efficacy of octreotide in preventing POPF, a critical concern regarding its inconsistent efficacy within the PD subgroup persists. This variability indicates that the overall clinical benefit of octreotide may be predominantly attributable to its utility in non-PD pancreatic resections.

Myocardial ischemia-reperfusion injury (MIRI) is an important complication in the treatment of heart failure, and its treatment has not made satisfactory progress. Nitroxyl (HNO) showed protective effects on the heart failure, however, the effect and underlying mechanism of HNO on MIRI remain largely unclear. MIRI model in this study was established to induce H9C2 cell injury through hypoxia/reoxygenation (H/R) in vitro. The cell viability was assessed by cell counting kit-8 assay. The effect of HNO on the apoptosis was detected by flow cytometry. DCFH-DA fluorescent probe method was applied to detect the level of intracellular reactive oxygen species (ROS). The morphology of mitochondria and autophagosomes were observed by transmission electron microscopy. Apoptosis, autophagy and PI3K/Akt/mTOR pathway-related proteins were detected by western blot. The viability of H9C2 cells was significantly increased in the HNO group. HNO inhibited apoptosis and regulated expressions of key apoptotic protein, including Bax and Bcl-2. HNO reduced ROS levels and alleviated H/R-induced mitochondrial damage. HNO also inhibited autophagy and regulated expressions of key autophagy-related molecules, including LC3II, p62 and Beclin1. Further experiments demonstrated that the effects of HNO were mediated through upregulation of PI3K/Akt/mTOR pathway. Rapamycin reversed the inhibition of HNO on H/R-induced autophagy in H9C2 cells, which abrogated the protective effect of HNO. This study provided the first evidence that HNO protected H/R-induced cardiomyocytes through inhibiting autophagy via the activation PI3K/Akt/mTOR pathway.

A virtual learning community (VLC) is a learning-based integrated platform based on a network sharing mechanism. In a VLC, users are not only the extractors of knowledge results but also the source of the platform knowledge base. The continuous knowledge sharing and communication of VLC users promote the sustainable development of the community. Studying the continuous use behavior of users in the VLC for the sustainable development of the community is of great importance. This study introduces the perceptual normativeness, perceptual enjoyment, perceptual interactivity, and perceptual value variables on the basis of the extended expectation confirmation model of the information system continuance model. After checking and correcting the prediction questionnaire twice, we adopted the \"Questionnaire Star\" network system to distribute the questionnaire and conducted offline questionnaire surveys of borrowers of Shandong University Library, University of Jinan Library, and Shandong Library. A theoretical model of the continuous use behavior of users in the VLC is constructed using the structural equation model. The survey data were empirically analyzed to explore the influencing factors and mechanism of the continuous use behavior of users in the VLC. Interaction perception, value perception, and perceptual normativeness exerted a significant positive impact on user-perceived usefulness and expectation confirmation, whereas perceptual enjoyment had little effect on perceived usefulness. This study also summarized the relationship between users' continuous use behavior, continuous willingness and perceived usefulness, expectation confirmation, satisfaction, self-efficacy, and contributing factors in the VLC on the basis of the data results. Suggestions for solving the identified problems are put forward.

The direct current circuit breakers are considered a promising option to protect the transmission line against commonly appearing line-to-ground fault. However, the challenges of losses in the nonoperational stage, escalation of response against fault current, and large fault current handling capability remain the debatable issues for direct current circuit breakers. This paper introduces a novel topology of the hybrid circuit breaker with fault-current-limiting characteristics, which contains three branches: the main branch, fault-current-limiting branch, and energy absorption branch. The main branch includes a mechanical switch, breaker impedance, and bidirectional power electronics switches. In the fault-current-limiting branch, a fault-current-limiting circuit is introduced which contains n numbers of bidirectional switches and current-limiting inductors, which are connected in series to make the design modular in nature. During the normal working stage, the current flows through the main branch of the breaker. Once a fault in the system is confirmed, the fault current is transferred to the fault-current-limiting branch. At this stage, the intensity of the fault current is reduced significantly using the fault-current-limiting circuit, and finally, the residual current is shifted to the energy absorption branch. The working principle, design considerations, and parametric analysis concerning the design of hybrid circuit breakers are incorporated in this paper. The performance of the proposed breaker is evaluated using a three-terminal voltage-source converter-based high-voltage direct current transmission network; for this purpose, a PSCAD/EMTDC simulation tool is used. The performance of the proposed breaker is also compared with other topologies. The comparative analysis shows that the proposed breaker is a good alternative considering high fault current interruption requirements, response time against fault current, and power losses.

Iron is increasingly recognized to influence glucose metabolism. However, evidence about the linkage between body iron stores and the risk of developing gestational diabetes mellitus (GDM) is still inconclusive. We aimed to prospectively investigate the association of serum ferritin concentrations with GDM. We studied 847 women from Peking University International Hospital from December 2017 to March 2019. Serum ferritin concentrations were measured three times during pregnancy (gestational weeks 6-12, 24-28 and 32-34). GDM was diagnosed by a 75-g oral-glucose-tolerance test (OGTT) at 24-28 weeks' gestation. Logistic regression analyses were carried out to determine the influence of serum ferritin at the first and second trimester on the risk of developing GDM. Among 847 participants, 73 women (8.6%) developed GDM. The median (IQR) of serum ferritin concentrations were 50.6 (32.4-75.5) ng/mL at gestational weeks 6-12, 19.7 (12.0-28.4) ng/mL at gestational weeks 24-28 and 19.4 (11.4-27.2) ng/mL at gestational weeks 32-34. The median serum ferritin concentrations were all significantly higher in women with GDM than those without GDM at the first, second and third trimester. Ferritin concentrations were positively correlated with the risk of GDM; the adjusted OR (95% CI) for highest vs lowest quartile was 2.97 (1.36, 6.51) at the first trimester and 2.64 (1.26, 5.54) at the second trimester. Elevated serum ferritin concentrations in the first and second trimester during pregnancy are both independently associated with increased risk of GDM.

Iron is increasingly recognized to influence glucose metabolism. However, evidence about the linkage between body iron stores and the risk of developing gestational diabetes mellitus (GDM) is still inconclusive. We aimed to prospectively investigate the association of serum ferritin concentrations with GDM. We studied 847 women from Peking University International Hospital from December 2017 to March 2019. Serum ferritin concentrations were measured three times during pregnancy (gestational weeks 6-12, 24-28 and 32-34). GDM was diagnosed by a 75-g oral-glucose-tolerance test (OGTT) at 24-28 weeks' gestation. Logistic regression analyses were carried out to determine the influence of serum ferritin at the first and second trimester on the risk of developing GDM. Among 847 participants, 73 women (8.6%) developed GDM. The median (IQR) of serum ferritin concentrations were 50.6 (32.4-75.5) ng/mL at gestational weeks 6-12, 19.7 (12.0-28.4) ng/mL at gestational weeks 24-28 and 19.4 (11.4-27.2) ng/mL at gestational weeks 32-34. The median serum ferritin concentrations were all significantly higher in women with GDM than those without GDM at the first, second and third trimester. Ferritin concentrations were positively correlated with the risk of GDM; the adjusted OR (95% CI) for highest vs lowest quartile was 2.97 (1.36, 6.51) at the first trimester and 2.64 (1.26, 5.54) at the second trimester. Elevated serum ferritin concentrations in the first and second trimester during pregnancy are both independently associated with increased risk of GDM.

As the share of renewable energy generation continues to increase, the new-type power system exhibits the characteristics of coordinated operation between the main grid, distribution networks, and microgrids. The microgrid is primarily concerned with achieving self-balancing between power sources, the network, loads, and storage. In decentralized multi-microgrid (MMG) access scenarios, the aggregation of distributed energy within a region enables the unified optimization of scheduling, which improves regional energy self-sufficiency while mitigating the impact and risks of distributed energy on grid operations. However, the cooperative operation of MMGs involves interactions among various stakeholders, and the absence of a reasonable operational mechanism can result in low energy utilization, uneven resource allocation, and other issues. Thus, designing an effective MMG operation strategy that balances the interests of all stakeholders has become a key area of focus in the industry. This paper examines the definition and structure of MMGs, analyzes their current operational challenges, compiles existing research methods and practical experiences, explores synergistic operational mechanisms and strategies for MMGs under different transaction models, and puts forward prospects for future research directions.

Semiconductor lasers with extremely low threshold power require a combination of small volume active region with high-quality-factor cavities. For ridge lasers with highly reflective coatings, an ultra-low threshold demands significantly suppressing the diffraction loss at the facets of the laser. Here, we demonstrate that introducing a subwavelength aperture in the metallic highly reflective coating of a laser can correct the phase front, thereby counter-intuitively enhancing both its modal reflectivity and transmissivity at the same time. Theoretical and experimental results manifest a decreasing in the mirror loss by over 40% and an increasing in the transmissivity by 10 4 . Implementing this method on a small-cavity quantum cascade laser, room-temperature continuous-wave lasing operation at 4.5 μm wavelength with an electrical consumption power of only 143 mW is achieved. Our work suggests possibilities for future portable applications and can be implemented in a broad range of optoelectronic systems. Low threshold lasing is widely required, especially for portable systems. Here the authors design a circular subwavelength metallic aperture in a QCL to shape its phase front and control diffraction losses, which in turn allows a lower threshold dissipation power, enabling the fabrication of shorter cavities.