23 research outputs found
Distribution of the Asiatic golden cat (Catopuma temminckii) and variations in its coat morphology in China
Abstract Of the 12 wild felid species found in China, Asiatic golden cat (Catopuma temminckii) is one of the least studied species. This medium‐sized cat with a prominently polymorphic coat was once distributed across much of southern China, but is believed to have experienced severe decline and range contraction during the past decades, primarily due to anthropogenic pressures. A lack of knowledge of its current distribution, ecology, and natural history has greatly hindered the implementation of conservation and management actions for this species. In this study, for the first time, we compiled the state‐wide occurrence records (N = 409), mainly from the camera‐trapping surveys, of Asiatic golden cats from 2008 to 2019, and predicted its distribution across the country through species distribution modeling using random forest algorithm. The results showed that the predicted habitats were mainly located in southwest China and suggested a rather low probability of possible current distribution across its vast historic range in central, eastern, and southern China. We divided its current range into four geographic regions (i.e., Qinling Mountains, Hengduan Mountains, East Himalayas, and southern Yunnan region) and considered the cats in each region as a regional population within the country. From the 287 camera‐trapping detections with photographs and/or videos collected across all populations, we identified six coat morphs and determined their occurrence percentages: common golden (47.4%), spotted (20.9%), red (13.6%), dark cinnamon (10.1%), melanistic (7.0%), and gray (1.0%). The complexity of coat morph composition within regional populations showed an increasing gradient from northeast to southwest. Among the four regional populations, the East Himalayas hosted the highest abundance and coat variation with all six morphs recorded. Our study results update the current distribution and coat morphology variations of this elusive cat in China and provide important knowledge to guide future research and conservation planning for this threatened species
A Muti-Substrate Flavonol <i>O</i>-glucosyltransferases from Safflower
To explore the complete biosynthesis process of flavonoid glycosides in safflower, specifically the key glycosyltransferase that might be involved, as well as to develop an efficient biocatalyst to synthesize flavonoid glycosides, a glycosyltransferase CtUGT4, with flavonoid-O-glycosyltransferase activity, was identified in safflower. The fusion protein of CtUGT4 was heterologously expressed in Escherichia coli, and the target protein was purified. The recombinant protein can catalyze quercetin to form quercetin-7-O-glucoside, and kaempferol to form kaempferol-3-O in vitro, and a series of flavones, flavonols, dihydroflavones, chalcones, and chalcone glycosides were used as substrates to generate new products. CtUGT4 was expressed in the tobacco transient expression system, and the enzyme activity results showed that it could catalyze kaempferol to kaempferol-3-O-glucoside, and quercetin to quercetin-3-O-glucoside. After overexpressing CtUGT4 in safflower, the content of quercetin-3-O-rutinoside in the safflower florets increased significantly, and the content of quercetin-3-O-glucoside also tended to increase, which preliminarily confirmed the function of CtUGT4 flavonoid-O-glycosyltransferase. This work demonstrated the flavonoid-O-glycosyltransferase function of safflower CtUGT4 and showed differences in the affinity for different flavonoid substrates and the regioselectivity of catalytic sites in safflower, both in vivo and in vitro, providing clues for further research regarding the function of UGT genes, as well as new ideas for the cultivation engineering of the directional improvement of effective metabolites in safflower
Temperature gradient zoning of steel beams without paving layers in China
The solar temperature field and its temperature effects on the straddle monorail tourist transportation system (SMTTS) significantly affect its mechanical performance. To investigate the distribution law of the daylight temperature field of the unpaved steel beams, the daylight temperature fields of box-type and I-sectional steel beams in different regions were measured and simulated. With the simulation results, the vertical temperature gradient curves of the unpaved steel girders were determined. Afterward, with the historical meteorological data as variables, the parameters of the extreme value model of generalized extreme value (GEV) distribution were obtained, and the representative values of temperature differences in China, based on the recurrence period, were analyzed. By analyzing the temperature difference values in 34 cities in China, an empirical prediction formula for the representative temperature difference value with three parameters was proposed, and the temperature gradient partition was established. The results indicated that the vertical temperature gradients of closed-section steel box girders are about 2–3 °C greater than that of open-section I-beams. Moreover, there are apparent geographical differences in the temperature difference values of steel girders
Graph neural network based approach to automatically assigning common weakness enumeration identifiers for vulnerabilities
Abstract Vulnerability reports are essential for improving software security since they record key information on vulnerabilities. In a report, CWE denotes the weakness of the vulnerability and thus helps quickly understand the cause of the vulnerability. Therefore, CWE assignment is useful for categorizing newly discovered vulnerabilities. In this paper, we propose an automatic CWE assignment method with graph neural networks. First, we prepare a dataset that contains 3394 real world vulnerabilities from Linux, OpenSSL, Wireshark and many other software programs. Then, we extract statements with vulnerability syntax features from these vulnerabilities and use program slicing to slice them according to the categories of syntax features. On top of slices, we represent these slices with graphs that characterize the data dependency and control dependency between statements. Finally, we employ the graph neural networks to learn the hidden information from these graphs and leverage the Siamese network to compute the similarity between vulnerability functions, thereby assigning CWE IDs for these vulnerabilities. The experimental results show that the proposed method is effective compared to existing methods
Short-term exposure to antimony induces hepatotoxicity and metabolic remodeling in rats
Antimony (Sb) poses a significant threat to human health due to sharp increases in its exploitation and application globally, but few studies have explored the pathophysiological mechanisms of acute hepatotoxicity induced by Sb exposure. We established an in vivo model to comprehensively explore the endogenous mechanisms underlying liver injury induced by short-term Sb exposure. Adult female and male Sprague-Dawley rats were orally administrated various concentrations of potassium antimony tartrate for 28 days. After exposure, the serum Sb concentration, liver-to-body weight ratio, and serum glucose levels significantly increased in a dose-dependent manner. Body weight gain and serum concentrations of biomarkers of hepatic injury (e.g., total cholesterol, total protein, alkaline phosphatase, and the aspartate aminotransferase/alanine aminotransferase ratio) decreased with increasing Sb exposure. Through integrative non-targeted metabolome and lipidome analyses, alanine, aspartate, and glutamate metabolism; phosphatidylcholines; sphingomyelins; and phosphatidylinositols were the most significantly affected pathways in female and male rats exposed to Sb. Additionally, correlation analysis showed that the concentrations of certain metabolites and lipids (e.g., deoxycholic acid, N-methylproline, palmitoylcarnitine, glycerophospholipids, sphingomyelins, and glycerol) were significantly associated with hepatic injury biomarkers, indicating that metabolic remodeling may be involved in apical hepatotoxicity. Our study demonstrated that short-term exposure to Sb induces hepatotoxicity, possibly through a glycolipid metabolism disorder, providing an important reference for the health risks of Sb pollution
Feasibility of a Percutaneous and Non-Fluoroscopic Procedure for Transcatheter Mitral Valve Edge-to-Edge Repair
Background: Transcatheter edge-to-edge repair (TEER) of the mitral valve has emerged as an alternative treatment for mitral regurgitation (MR). However, the high radiation exposure during the process has been associated with multiple adverse effects for medical staff. In this study, we assessed the feasibility and safety of TEER performed solely under the echocardiographic (echo) guidance. Methods: Between April 2021 to August 2021, we retrospectively collected characteristics of 23 patients with MR who underwent TEER under echocardiographic guidance exclusively. Follow-up evaluations were performed at 1- , 3-months and 1-year post procedure. Results: All 23 patients (mean age, 66.1 ± 12.1 years; 65.2% males) successfully underwent echo-guided TEER, with 22 patients under transesophageal echo (TEE) guidance and 1 patient under transthoracic echo (TTE) guidance for severe esophageal stenosis. Of the patients, 60.9% received 1 implant and 39.1% received 2 implants. The median total procedural time was 130 (interquartile range, IQR: 90–150) min and the device procedure time was 73 (IQR: 58–100) min. The median length of stay was 6 (IQR: 5–9) days. At 3-months follow-up, 63.6% of patients had an MR ≤1+ and 90.9% had an MR ≤2+ (p < 0.001 vs. baseline). Improvement in functional status was observed, with 40.9% of patients classified as New York Heart Association (NYHA) functional class I and 45.5% as NYHA functional class II (p < 0.001 compared to baseline) at 3-months. At 1-year follow-up, 90.4% maintained MR reduction with MR ≤2+ (p < 0.001 vs. baseline). Single leaflet device attachment (SLDA) occurred in one patient (4.3%) 1-week post procedure. Conclusions: This retrospective, single-center, and pilot study demonstrates the feasibility, safety, and low complication rates of TEER guided solely by echocardiography. Our findings support the systematic use of echocardiography as the sole guidance modality for TEER, highlighting its potential as an alternative to fluoroscopy-guided procedures. Further multicenter and comparative studies are warranted to confirm these results and provide a more comprehensive evaluation of this approach
Design of a graphene-based core–shell structure for the improvement of photothermic performance
Complete Suppression of Phase Segregation in Mixed-Halide Perovskite Nanocrystals under Periodic Heating
Under continuous light illumination, it is known that localized domains with segregated halide compositions form in semiconducting mixed-halide perovskites, thus severely limiting their optoelectronic applications due to the negative changes in bandgap energies and charge-carrier characteristics. Here mixed-halide perovskite CsPbBr1.2I1.8 nanocrystals are deposited onto an indium tin oxide substrate, whose temperature can be rapidly changed by ≈10 °C in a few seconds by applying or removing an external voltage. Such a sudden temperature change induces a temporary transition of CsPbBr1.2I1.8 nanocrystals from the segregated phase to the mixed phase, the latter of which can be permanently maintained when the light illumination is coupled with periodic heating cycles. These findings mark the emergence of a practical solution to the detrimental phase-segregation problem, given that a small temperature modulation is readily available in various fundamental studies and practical devices of mixed-halide perovskites.</p