Natural products(NPs)have historically been a fundamental source for drug discovery.Yet the complex nature of NPs presents substantial challenges in pinpointing bioactive constituents,and corresponding targets.In the ...Natural products(NPs)have historically been a fundamental source for drug discovery.Yet the complex nature of NPs presents substantial challenges in pinpointing bioactive constituents,and corresponding targets.In the present study,an innovative natural product virtual screening-interaction-phenotype(NP-VIP)strategy that integrates virtual screening,chemical proteomics,and metabolomics to identify and validate the bioactive targets of NPs.This approach reduces false positive results and enhances the efficiency of target identification.Salvia miltiorrhiza(SM),a herb with recognized therapeutic potential against ischemic stroke(IS),was used to illustrate the workflow.Utilizing virtual screening,chemical proteomics,and metabolomics,potential therapeutic targets for SM in the IS treatment were identified,totaling 29,100,and 78,respectively.Further analysis via the NP-VIP strategy highlighted five high-confidence targets,including poly[ADP-ribose]polymerase 1(PARP1),signal transducer and activator of transcription 3(STAT3),amyloid precursor protein(APP),glutamate-ammonia ligase(GLUL),and glutamate decarboxylase 67(GAD67).These targets were subsequently validated and found to play critical roles in the neuroprotective effects of SM.The study not only underscores the importance of SM in treating IS but also sets a precedent for NP research,proposing a comprehensive approach that could be adapted for broader pharmacological explorations.展开更多
In the long process of living, working and fighting against diseases, the Jing people have formed a medical system with their own characteristics, which has made great contributions to the hygiene and health of the et...In the long process of living, working and fighting against diseases, the Jing people have formed a medical system with their own characteristics, which has made great contributions to the hygiene and health of the ethnic group and is still playing an important role today. As an indispensable part of Chinese traditional medicine system, Jingzu medicine has its own unique advantages and characteristics, which need to be further explored and sorted out. In this paper, the characteristics and advantages of Peking medicine were summarized from the characteristics of medicine use.展开更多
The ablation behaviour of(Hf-Ta-Zr-Nb)C high entropy carbide(HEC4)was studied at temperatures above 2100℃using a plasma flame gun in air.The microstructures,phase and chemical compositions of the HEC4 samples were in...The ablation behaviour of(Hf-Ta-Zr-Nb)C high entropy carbide(HEC4)was studied at temperatures above 2100℃using a plasma flame gun in air.The microstructures,phase and chemical compositions of the HEC4 samples were investigated after ablation.The mass ablation rate of the HEC4 samples increased with increasing ablation time from 0.21 mg cm^(−2)s^(−1)for 60 s to 0.45 mg cm^(−2)s^(−1)for 120 s.Com-pared to the mono-and binary carbides with commonly decreased mass and thickness after ablation,the HEC4 samples with the increased mass and thickness after ablation showed good resistance to mechan-ical scouring at such high temperatures and an oxidation controlled ablation mechanism.The ablation processes mainly include the oxidation of the carbide,the phase separation of the oxides,the melting of oxides,and the diffusion of oxygen.A composition gradient in the oxide layer was detected due to the different melting temperatures of the different oxides;Nb-Ta rich oxides formed at the front surface melted and became enriched at the edge of the samples,and the Zr-Hf rich oxides were enriched in the centre of the samples.The oxide layer with complex compositions and phase distributions acted as an effective ablation barrier.展开更多
The Chang’E-4 mission has been exploring the lunar farside.Two scientific targets of the rover onboard are(1)resolving the possible mineralogy related to the South Pole-Aitken basin and(2)understanding the subsurface...The Chang’E-4 mission has been exploring the lunar farside.Two scientific targets of the rover onboard are(1)resolving the possible mineralogy related to the South Pole-Aitken basin and(2)understanding the subsurface processes at the lunar farside.Publications to date that are based on the reflectance spectra and radar data obtained by the rover have shown a persistent inconsistency about the local stratigraphy.To explain both the abnormal surface topography at the landing site and the unexpected radargram observed by the rover,the Alder crater has been frequently reported to be older than the mare basalts at that landing site.However,this argument is not supported by earlier geological mapping nor recent crater statistics.Resolving this controversy is critical for a full understanding of the geological history of the landing area and for correct interpretations of the scientific data returned.Employing detailed crater statistics,rigorous statistical analyses,and an updated crater chronology function,this study is determined to resolve the relative ages of the Alder crater,Finsen crater,and the mare basalts on the floor of Von Kármán.Our results reveal that while background secondaries and local resurfacing have widely occurred in the study area,affecting age determinations,the statistics are significant enough to conclude that the Alder crater is the oldest among the three targets.This independent constraint is consistent with both the crosscutting relationships of different terrains in this area and global stratigraphic mapping.Our results exclude Alder as a possible contributor of the post-mare deposits at the landing site,appealing for a more systematic stratigraphy study to resolve the provenances of these deposits.展开更多
Microcystin-LR （MC-LR） is the most abundant and toxic microcystin congener and has been classified as a potential human carcinogen （Group 2B） by the International Agency for Research on Cancer. However, the mechan...Microcystin-LR （MC-LR） is the most abundant and toxic microcystin congener and has been classified as a potential human carcinogen （Group 2B） by the International Agency for Research on Cancer. However, the mechanisms underlying the genotoxic effects of MC-LR during chronic exposure are still poorly understood. In the present study, human-hamster hybrid （AL） cells were exposed to MC-LR for varying lengths of time to investigate the role of nitrogen radicals in MC-LR-induced genotoxicity. The mutagenic potential at the CD59 locus was more than 2-fold higher （p 〈 0.01） in AL ceUs exposed to a cytotoxic concentration （1 μmol/L） of MC-LR for 30 days than in untreated control ceils, which was consistent with the formation of micronucleus. MC-LR caused a dose-dependent increase in nitric oxide （NO） production in treated cells. Moreover, this was blocked by concurrent treatment with the NO synthase inhibitor NC-methyl-L-arginine （L-NMMA）, which suppressed MC-LR- induced mutations as well. The survival of mitochondrial DNA-depleted （pO） AL ceils was markedly decreased by MC-LR treatment compared to that in AL cells, while the CD59 mutant fraction was unaltered. These results provided clear evidence that the genotoxicity associated with chronic MC-LR exposure in mammalian cells was mediated by NO and might be considered as a basis for the development of therapeutics that prevent carcinogenesis.展开更多
The Lidang circular structure in the center of the Guangxi Province is about 8 km in diameter. This structure appears as an abnormal shallow depression that has disturbed the rather harmonic regional joint systems. It...The Lidang circular structure in the center of the Guangxi Province is about 8 km in diameter. This structure appears as an abnormal shallow depression that has disturbed the rather harmonic regional joint systems. Its unique occurrence in the whole region, the circular morphology, negative topography, and the spatial distribution of interior and exterior strata are all consistent with those of impact craters that are formed by asteroidal or cometary collision. To test the impact hypothesis, we carried out both field investigation and remote sensing study of this structure. Regional geological history suggests that if the impact hypothesis were correct, the impact event should have occurred at or after the Early Permian. Field investigation found that the strata inside and outside the crater are dominated by parallel stacks of Lower and Upper Permian limestone that have various thicknesses and different mud contents. The layers of limestone within and outside the circular structure have identical attitudes;no structural disturbances were visible in the outcrops. Field investigations provide conclusive evidence against the impact cratering hypothesis. A high-resolution digital elevation model shows that the spatial distribution of rounded mountains within the structure is controlled by faint but continual extension of joints, suggesting that the crater interior has gone through a much higher degree of erosion. Therefore, regional joints that had once existed within the crater are preserved less well than exterior terrains, forming the abruptly disrupted circular depression. Differential erosion, as the possible formation mechanism of the Lidang structure, is consistent with the different mud contents found between the interior and exterior limestone. The circular outline of this structure may correspond to the shape of the original deposition basin. In conclusion, the Lidang circular structure is a polje formed by karstification, not an astrobleme.展开更多
INTRODUCTION Japan’s first successful lunar landing mission,Smart Lander for Investigating Moon(SLIM),was landed on the Moon on January 19th,2024.SLIM made a precise landing within 100 m of the targeted landing zone(...INTRODUCTION Japan’s first successful lunar landing mission,Smart Lander for Investigating Moon(SLIM),was landed on the Moon on January 19th,2024.SLIM made a precise landing within 100 m of the targeted landing zone(central coordinates 13.316°S,25.251°E),which is located around the Shioli crater(D=270 m,central coordinates as 13.33°S,25.23°E)in the southwestern ejecta of the Theophilus crater(D=98.6 km,central coordinates as 11.45°S,26.28°E).展开更多
Objective:To explore the effectiveness and safety of cardiac rehabilitation qigong exercise in stable coronary artery disease(CAD)patients undergoing phaseⅢrehabilitation.Methods:This was a randomized controlled tria...Objective:To explore the effectiveness and safety of cardiac rehabilitation qigong exercise in stable coronary artery disease(CAD)patients undergoing phaseⅢrehabilitation.Methods:This was a randomized controlled trial.A total of 59 stable CAD patients undergoing phaseⅢrehabilitation treated in Sports Medicine Hospital from March 2017 to September 2017 were enrolled after meeting the inclusion criteria and then divided into cardiac rehabilitation qigong exercise group(n=30)receiving a 12-week intervention and control group(n=29).All participants were assessed at baseline and at 12-week intervention for the primary outcome,that was treadmill test parameter and the secondary outcomes including physical fitness,body composition,bone mineral density,and cardiac ultrasound B-mode imaging.Results:There were no significant differences in baseline demographics between the two groups.After a 12-week cardiac rehabilitation qigong exercise intervention,compared with the control group,ΔV02(initial 1352.63±340.95 vs 12 weeks 1594.57±467.14)vs(initial 1363.83±322.90 vs 12 weeks 1323.76±318.92)(P=.003),ΔVO2/kg(initial 21.23±3.56 vs 12 weeks 24.75±5.11)vs(initial 21.01±3.71 vs 12 weeks 20.35±3.66)(P=.002),ΔMETS(initial 6.19±1.12 vs 12 weeks 7.16±1.60)vs(initial 6.00±1.19 vs 12 weeks 5.86±1.23)(P=.001),ΔVO2/HR(P=.027),ΔSV(P=.014),ΔOUES(P=.012),Δhand-grip strength(P=.002),Δflexibility(P=.001),Δbalance(P=.002),ΔT-score(P=.042),ΔBQI(P=.018).However,Δresting systolic blood pressure(P=.004)andΔresting diastolic pressure(P=.012)decreased in the cardiac rehabilitation qigong exercise group.Conclusion:Cardiac rehabilitation qigong exercise can improve cardiopulmonary aerobic capacity,physical fitness,bone mineral density in patients with stable CAD,suggesting that certain effect and safety for stable CAD patients undergoing phaseⅢrehabilitation can be obtained.展开更多
To improve the corrosion resistance of Cf/SiC composites in a water vapor oxygen coupled environment,the bilayer Yb_(2)Si_(2)O_(7)/SiC and tri-layer Yb2Si2O7/(SiCw-Mullite,SM)/SiC environment barrier coatings were des...To improve the corrosion resistance of Cf/SiC composites in a water vapor oxygen coupled environment,the bilayer Yb_(2)Si_(2)O_(7)/SiC and tri-layer Yb2Si2O7/(SiCw-Mullite,SM)/SiC environment barrier coatings were designed and prepared on the surface of Cf/SiC composites by chemical vapor deposition and sol-gel method united with air spraying.Results show that the mass loss of bi-layer Yb_(2)Si_(2)O_(7)/SiC coating coated samples was 17.24×10^(-3) g cm^(-2) after 200 h oxidation at 1673 K,and the average compression strength retention rate was only 79.44% due to the formation of wide penetrating cracks.Comparatively,SiC whiskers in SM middle coating can not only increase the crack propagation resistance of mullite middle coating,but also alleviate the difference of coefficient of thermal expansion between Yb_(2)Si_(2)O_(7) outer coating and mullite middle coating.Therefore,the mass loss of trilayer Yb_(2)Si_(2)O_(7)/SM/SiC coating coated samples was only 2.93×10^(-3) g cm^(-2) after 200 h oxidation at 1673 K,and the average compression strength retention rate was up to 98.79%.展开更多
In the post-Covid-19 pandemic era,it is more difficult for some Chinese schools in Europe to provide online extra classes for overseas Chinese children after school hours,as they did previously.To meet students'mu...In the post-Covid-19 pandemic era,it is more difficult for some Chinese schools in Europe to provide online extra classes for overseas Chinese children after school hours,as they did previously.To meet students'multifaceted learning needs,online extra classes teaching,including online Chinese language classes and some online art classes,is increasingly being offered as a supplement to the diversity of teaching activities in Chinese schools in Europe,with the ultimate goal of improving the learning abilities of overseas Chinese children while relieving pressure on teaching resources in schools.Children’s learning self-efficacy in online extracurricular courses has its own uniqueness,which can be considered from three dimensions,including learning confidence,learning ability,and self-assessment ability.This study aims to examine the factors influencing the self-efficacy of overseas Chinese children and to make optimization suggestions for better teaching methods.In search of that,an online questionnaire survey with 127 participants from overseas Chinese children agedtowas collected.The findings indicate that the role of learning confidence in overseas Chinese children outweighs their learning ability and self-assessment ability.Gender and age have a negligible effect on self-efficacy but have an impact on learning confidence.Chinese schools in Europe do not need to show gender differences when conducting classroom activities in online teaching to improve the online self-efficacy of Chinese children,and efforts should also be made to keep the courage of older students to trial and error.Teachers are expected to investigate more aspects of their students'personalities in future classrooms rather than sticking to a consistent and unchanging teaching model.展开更多
Hf-based carbides are highly desirable candidate materials for oxidizing environments above 2000℃.However,the static oxidation behavior at their potential service temperatures remains unclear.To fill this gap,the sta...Hf-based carbides are highly desirable candidate materials for oxidizing environments above 2000℃.However,the static oxidation behavior at their potential service temperatures remains unclear.To fill this gap,the static oxidation behavior of(Hf,Ti)C and the effect of Ti substitutions were investigated in air at 2500℃ under an oxygen partial pressure of 4.2 kPa.After oxidation for 2000 s,the thickness of the oxide layer on the surface of(Hf,Ti)C bulk ceramic is reduced by 62.29%compared with that on the HfC monocarbide surface.The dramatic improvement in oxidation resistance is attributed to the unique oxide layer structure consisting of various crystalline oxycarbides,HfO_(2),and carbon.The Ti-rich oxycarbide((Ti,Hf)C_(x)O_(y))dispersed within HfO_(2) formed the major structure of the oxide layer.A coherent boundary with lattice distortion existed at the HfO2/(Ti,Hf)C_(x)O_(y) interface along the(111)crystal plane direction,which served as an effective oxygen diffusion barrier.The Hfrich oxycarbide((Hf,Ti)CxOy)together with(Ti,Hf)C_(x)O_(y),HfO_(2),and precipitated carbon constituted a dense transition layer,ensuring favorable bonding between the oxide layer and the matrix.The Ti content affects the oxidation resistance of(Hf,Ti)C by determining the oxide layer's phase distribution and integrity.展开更多
High-hardness rock-salt structured transitional metal carbides(TMC)are attracting substantial interest as potential next-generation thermal protection materials.However,the intrinsic brittleness of TMC ceramics impede...High-hardness rock-salt structured transitional metal carbides(TMC)are attracting substantial interest as potential next-generation thermal protection materials.However,the intrinsic brittleness of TMC ceramics impedes their performance in aerodynamically harsh environments.In this work,a promising strategy is proposed to introduce plasticity in TaC–HfC solid solutions by manipulating carbon deficiency.The approach combines density-functional theory(DFT)with experiments and takes Pugh's ratio(k)as the criteria.Depletion of carbon atoms in TaC–HfC solid solutions results in the de-localizing of valence electrons,deviation of spatial modulus along different crystal plane directions,and leading to significant elastic anisotropy.The carbon deficient Ta_(0.8)Hf_(0.2)C_(0.8) is predicted to be a‘softer phase’with reduced modulus and Pugh's ratio(k=0.58).A series of Ta1–xHfxCy(x=0.2 and 0.8,y=0.8,0.9,and 1.0)bulk ceramics are experimentally fabricated by an excessive metal alloying method.Trigonal and hexagonal close-packed structured carbides are derived when the carbon deficiency y decreased to 0.7.The indentation modulus drops from 641.8±14.8 GPa for Ta_(0.8)Hf_(0.2)C_(1.0) to 555.8±9.9 GPa for Ta0.8Hf0.2C0.8.The specific stoichiometric composition of Ta_(0.8)Hf_(0.2)C_(0.8) is experimentally verified to possess both plasticity(k=0.41)and ultra-high nanohardness(41.3±1.3 GPa).展开更多
Objective:The aim of this study was to evaluate the effects of traditional Chinese exercises (TCEs) on stroke risk factors in patients with pre-hypertension or mild-to-moderate essential hypertension.Methods:We perfor...Objective:The aim of this study was to evaluate the effects of traditional Chinese exercises (TCEs) on stroke risk factors in patients with pre-hypertension or mild-to-moderate essential hypertension.Methods:We performed searches of seven electronic databases for studies published from their inception until July 2017.We included randomized controlled trials (RCTs) of the effects of TCEs with or without health education on stroke risk factors in patients with prehypertension or mild-to-moderate essential hypertension.Outcomes were independently extracted from each study by two authors and were pooled to determine risk ratios and standardized mean differences.materials-methodsResults:We included 15 RCTs,involving 1272 hypertensive participants.Compared with no intervention,TCEs were associated with a clinically meaningful amelioration of stroke risk factors,including reductions in systolic blood pressure (SBP),diastolic blood pressure (DBP),fasting blood glucose,blood lipids,and waist-to-hip ratio,and improved quality of life.Compared with health education,TCEs reduced SBP but had no effect on DBP.Compared with health education alone,TCEs plus health education resulted in an amelioration of stroke risk factors.No serious adverse events were reported.resultsConclusion:TCEs may be effective alongside health education in ameliorating stroke risk factors in individuals with pre-hypertension or mild-to-moderate essential hypertension.However,the current evidence is insufficient due to poor methodology and lack of adequate safety data.Further rigorously-designed RCTs are warranted.conclusion.展开更多
Based on the description of feedback in the literature and the classification of feedback by different scholars,this paper discusses the efficiency and possible issues of the teachers’use of different feedback in the...Based on the description of feedback in the literature and the classification of feedback by different scholars,this paper discusses the efficiency and possible issues of the teachers’use of different feedback in the teaching of second language writing.Through interviews with experienced English majors,this paper further demonstrates the importance of teachers'use of feedback in second language writing teaching.At the end of the paper,the author also shows that the combination of different feedback according to specific situations in teaching can better promote the writing proficiency of second language learners.展开更多
Nanoadditives offer a promising way to reduce friction and wear.In this study,an organic-inorganic hybrid material composed of MXene quantum dots(MQDs)and cetyl trimethylammonium bromide decorated covalent organic fra...Nanoadditives offer a promising way to reduce friction and wear.In this study,an organic-inorganic hybrid material composed of MXene quantum dots(MQDs)and cetyl trimethylammonium bromide decorated covalent organic frameworks(CNUS-2)is successfully constructed via an electrostatic self-assembly strategy.The combination of MQDs and CNUS-2 not only increases the interlayer spacing of NUS-2 but also mitigates the self-aggregation of MQDs,maximizing the advantages of their intrinsic characteristics.Owing to the synergistic lubrication effect of zero-dimensional MQDs and two-dimensional NUS-2,improved lubricity and interfacial bonding ability are realized.In addition,the relative slip between the CNUS-2@MQDs sheets can reduce friction and anti-wear.As expected,different levels of CNUS-2@MQDs effectively boost the tribological properties.The friction coefficient(0.097)and wear volume(1.48×10^(5)µm^(3))of PAO-10 oil are reduced by 46.7%and 92.6%respectively,after the introduction of the 3.0 wt%CNUS-2@MQDs nanocomposite.Furthermore,the abundant oxygen-containing functional groups in CNUS-2 can accelerate the formation of adsorption and tribochemical reaction films,whereas the MQDs can repair worn surfaces,resulting in superior lubrication performance under variable load,temperature,and frequency conditions.This work not only effectively improves lubrication performance by developing a unique CNUS-2@MQDs nanocomposite,but also provides a reference for the design of novel lubricant additives.展开更多
基金supported by the National Natural Science Foundations of China(Grant No.:82204584)Liaoning Provincial Science and Technology Projects,China(Project No.:2021JH1/10400055).
文摘Natural products(NPs)have historically been a fundamental source for drug discovery.Yet the complex nature of NPs presents substantial challenges in pinpointing bioactive constituents,and corresponding targets.In the present study,an innovative natural product virtual screening-interaction-phenotype(NP-VIP)strategy that integrates virtual screening,chemical proteomics,and metabolomics to identify and validate the bioactive targets of NPs.This approach reduces false positive results and enhances the efficiency of target identification.Salvia miltiorrhiza(SM),a herb with recognized therapeutic potential against ischemic stroke(IS),was used to illustrate the workflow.Utilizing virtual screening,chemical proteomics,and metabolomics,potential therapeutic targets for SM in the IS treatment were identified,totaling 29,100,and 78,respectively.Further analysis via the NP-VIP strategy highlighted five high-confidence targets,including poly[ADP-ribose]polymerase 1(PARP1),signal transducer and activator of transcription 3(STAT3),amyloid precursor protein(APP),glutamate-ammonia ligase(GLUL),and glutamate decarboxylase 67(GAD67).These targets were subsequently validated and found to play critical roles in the neuroprotective effects of SM.The study not only underscores the importance of SM in treating IS but also sets a precedent for NP research,proposing a comprehensive approach that could be adapted for broader pharmacological explorations.
文摘In the long process of living, working and fighting against diseases, the Jing people have formed a medical system with their own characteristics, which has made great contributions to the hygiene and health of the ethnic group and is still playing an important role today. As an indispensable part of Chinese traditional medicine system, Jingzu medicine has its own unique advantages and characteristics, which need to be further explored and sorted out. In this paper, the characteristics and advantages of Peking medicine were summarized from the characteristics of medicine use.
基金financially supported by the National Natural Science Foundation of China (Nos. 51602325, 91960102, and 51572224)the Natural Science Foundation of Shanghai (No.20ZR1465400)+1 种基金111 Project (No. BP0820014)financial support from China Scholarship Council
文摘The ablation behaviour of(Hf-Ta-Zr-Nb)C high entropy carbide(HEC4)was studied at temperatures above 2100℃using a plasma flame gun in air.The microstructures,phase and chemical compositions of the HEC4 samples were investigated after ablation.The mass ablation rate of the HEC4 samples increased with increasing ablation time from 0.21 mg cm^(−2)s^(−1)for 60 s to 0.45 mg cm^(−2)s^(−1)for 120 s.Com-pared to the mono-and binary carbides with commonly decreased mass and thickness after ablation,the HEC4 samples with the increased mass and thickness after ablation showed good resistance to mechan-ical scouring at such high temperatures and an oxidation controlled ablation mechanism.The ablation processes mainly include the oxidation of the carbide,the phase separation of the oxides,the melting of oxides,and the diffusion of oxygen.A composition gradient in the oxide layer was detected due to the different melting temperatures of the different oxides;Nb-Ta rich oxides formed at the front surface melted and became enriched at the edge of the samples,and the Zr-Hf rich oxides were enriched in the centre of the samples.The oxide layer with complex compositions and phase distributions acted as an effective ablation barrier.
基金the B-type Strategic Priority Program of the Chinese Academy of Sciences(Grant No.XDB41000000)the Science and Technology Development Fund of Macao(0042/2018/A2)+1 种基金the National Natural Science Foundation of China(No.41773063)the pre-research Project on Civil Aerospace Technologies(No.D020201 and D020202)that is funded by Chinese National Space Administration.
文摘The Chang’E-4 mission has been exploring the lunar farside.Two scientific targets of the rover onboard are(1)resolving the possible mineralogy related to the South Pole-Aitken basin and(2)understanding the subsurface processes at the lunar farside.Publications to date that are based on the reflectance spectra and radar data obtained by the rover have shown a persistent inconsistency about the local stratigraphy.To explain both the abnormal surface topography at the landing site and the unexpected radargram observed by the rover,the Alder crater has been frequently reported to be older than the mare basalts at that landing site.However,this argument is not supported by earlier geological mapping nor recent crater statistics.Resolving this controversy is critical for a full understanding of the geological history of the landing area and for correct interpretations of the scientific data returned.Employing detailed crater statistics,rigorous statistical analyses,and an updated crater chronology function,this study is determined to resolve the relative ages of the Alder crater,Finsen crater,and the mare basalts on the floor of Von Kármán.Our results reveal that while background secondaries and local resurfacing have widely occurred in the study area,affecting age determinations,the statistics are significant enough to conclude that the Alder crater is the oldest among the three targets.This independent constraint is consistent with both the crosscutting relationships of different terrains in this area and global stratigraphic mapping.Our results exclude Alder as a possible contributor of the post-mare deposits at the landing site,appealing for a more systematic stratigraphy study to resolve the provenances of these deposits.
基金supported by the National Basic Research Program (973) of China (No. 2014CB932002)the Chinese Academy of Sciences Strategic Priority Research Program (No. XDB14030502)the National Natural Science Foundation of China (Nos. 21177133, U1232144)
文摘Microcystin-LR （MC-LR） is the most abundant and toxic microcystin congener and has been classified as a potential human carcinogen （Group 2B） by the International Agency for Research on Cancer. However, the mechanisms underlying the genotoxic effects of MC-LR during chronic exposure are still poorly understood. In the present study, human-hamster hybrid （AL） cells were exposed to MC-LR for varying lengths of time to investigate the role of nitrogen radicals in MC-LR-induced genotoxicity. The mutagenic potential at the CD59 locus was more than 2-fold higher （p 〈 0.01） in AL ceUs exposed to a cytotoxic concentration （1 μmol/L） of MC-LR for 30 days than in untreated control ceils, which was consistent with the formation of micronucleus. MC-LR caused a dose-dependent increase in nitric oxide （NO） production in treated cells. Moreover, this was blocked by concurrent treatment with the NO synthase inhibitor NC-methyl-L-arginine （L-NMMA）, which suppressed MC-LR- induced mutations as well. The survival of mitochondrial DNA-depleted （pO） AL ceils was markedly decreased by MC-LR treatment compared to that in AL cells, while the CD59 mutant fraction was unaltered. These results provided clear evidence that the genotoxicity associated with chronic MC-LR exposure in mammalian cells was mediated by NO and might be considered as a basis for the development of therapeutics that prevent carcinogenesis.
基金supported by National Natural Science Foundation of China (Nos. 41773063 and 41830214)the Science and Technology Development Fund (FDCT) of Macao (0042/2018/A2)the Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) (Nos. CUG180601)
文摘The Lidang circular structure in the center of the Guangxi Province is about 8 km in diameter. This structure appears as an abnormal shallow depression that has disturbed the rather harmonic regional joint systems. Its unique occurrence in the whole region, the circular morphology, negative topography, and the spatial distribution of interior and exterior strata are all consistent with those of impact craters that are formed by asteroidal or cometary collision. To test the impact hypothesis, we carried out both field investigation and remote sensing study of this structure. Regional geological history suggests that if the impact hypothesis were correct, the impact event should have occurred at or after the Early Permian. Field investigation found that the strata inside and outside the crater are dominated by parallel stacks of Lower and Upper Permian limestone that have various thicknesses and different mud contents. The layers of limestone within and outside the circular structure have identical attitudes;no structural disturbances were visible in the outcrops. Field investigations provide conclusive evidence against the impact cratering hypothesis. A high-resolution digital elevation model shows that the spatial distribution of rounded mountains within the structure is controlled by faint but continual extension of joints, suggesting that the crater interior has gone through a much higher degree of erosion. Therefore, regional joints that had once existed within the crater are preserved less well than exterior terrains, forming the abruptly disrupted circular depression. Differential erosion, as the possible formation mechanism of the Lidang structure, is consistent with the different mud contents found between the interior and exterior limestone. The circular outline of this structure may correspond to the shape of the original deposition basin. In conclusion, the Lidang circular structure is a polje formed by karstification, not an astrobleme.
基金supported by the National Natural Science Foundation of China(Nos.42241108,42302263,62227901)the Strategic Priority Research Program of Chinese Academy of Science(No.XDB41000000).
文摘INTRODUCTION Japan’s first successful lunar landing mission,Smart Lander for Investigating Moon(SLIM),was landed on the Moon on January 19th,2024.SLIM made a precise landing within 100 m of the targeted landing zone(central coordinates 13.316°S,25.251°E),which is located around the Shioli crater(D=270 m,central coordinates as 13.33°S,25.23°E)in the southwestern ejecta of the Theophilus crater(D=98.6 km,central coordinates as 11.45°S,26.28°E).
文摘Objective:To explore the effectiveness and safety of cardiac rehabilitation qigong exercise in stable coronary artery disease(CAD)patients undergoing phaseⅢrehabilitation.Methods:This was a randomized controlled trial.A total of 59 stable CAD patients undergoing phaseⅢrehabilitation treated in Sports Medicine Hospital from March 2017 to September 2017 were enrolled after meeting the inclusion criteria and then divided into cardiac rehabilitation qigong exercise group(n=30)receiving a 12-week intervention and control group(n=29).All participants were assessed at baseline and at 12-week intervention for the primary outcome,that was treadmill test parameter and the secondary outcomes including physical fitness,body composition,bone mineral density,and cardiac ultrasound B-mode imaging.Results:There were no significant differences in baseline demographics between the two groups.After a 12-week cardiac rehabilitation qigong exercise intervention,compared with the control group,ΔV02(initial 1352.63±340.95 vs 12 weeks 1594.57±467.14)vs(initial 1363.83±322.90 vs 12 weeks 1323.76±318.92)(P=.003),ΔVO2/kg(initial 21.23±3.56 vs 12 weeks 24.75±5.11)vs(initial 21.01±3.71 vs 12 weeks 20.35±3.66)(P=.002),ΔMETS(initial 6.19±1.12 vs 12 weeks 7.16±1.60)vs(initial 6.00±1.19 vs 12 weeks 5.86±1.23)(P=.001),ΔVO2/HR(P=.027),ΔSV(P=.014),ΔOUES(P=.012),Δhand-grip strength(P=.002),Δflexibility(P=.001),Δbalance(P=.002),ΔT-score(P=.042),ΔBQI(P=.018).However,Δresting systolic blood pressure(P=.004)andΔresting diastolic pressure(P=.012)decreased in the cardiac rehabilitation qigong exercise group.Conclusion:Cardiac rehabilitation qigong exercise can improve cardiopulmonary aerobic capacity,physical fitness,bone mineral density in patients with stable CAD,suggesting that certain effect and safety for stable CAD patients undergoing phaseⅢrehabilitation can be obtained.
基金This work was funded by the National Natural Science Foundation of China(Grant No.52102122 and 52075555)Natural Science Foundation of Hunan Province(Grant No.2021JJ10057 and Grant No.2020JJ4116)the National Defense Basic Scientific Research Program of China(fund from National Key Laboratory of Science and Technology on Highstrength Structural Materials,Central South University,Changsha 410083,China)。
文摘To improve the corrosion resistance of Cf/SiC composites in a water vapor oxygen coupled environment,the bilayer Yb_(2)Si_(2)O_(7)/SiC and tri-layer Yb2Si2O7/(SiCw-Mullite,SM)/SiC environment barrier coatings were designed and prepared on the surface of Cf/SiC composites by chemical vapor deposition and sol-gel method united with air spraying.Results show that the mass loss of bi-layer Yb_(2)Si_(2)O_(7)/SiC coating coated samples was 17.24×10^(-3) g cm^(-2) after 200 h oxidation at 1673 K,and the average compression strength retention rate was only 79.44% due to the formation of wide penetrating cracks.Comparatively,SiC whiskers in SM middle coating can not only increase the crack propagation resistance of mullite middle coating,but also alleviate the difference of coefficient of thermal expansion between Yb_(2)Si_(2)O_(7) outer coating and mullite middle coating.Therefore,the mass loss of trilayer Yb_(2)Si_(2)O_(7)/SM/SiC coating coated samples was only 2.93×10^(-3) g cm^(-2) after 200 h oxidation at 1673 K,and the average compression strength retention rate was up to 98.79%.
基金This paper is funded by research project of National College Student Innovation and Entrepreneurship Project of Wenzhou University in 2022,“A Study of Teaching Practices and Validity of Online Extra Classes of Chinese Schools in Europe”under Project No.202210351019 and research project of Wenzhou University Student Scientific Research Project(“Challenge Cup”Special Project)in 2022“Qiaozhiqiao-Chinese Ethnic Identity Education of Overseas Chinese Children”under Project No.2022kx220.
文摘In the post-Covid-19 pandemic era,it is more difficult for some Chinese schools in Europe to provide online extra classes for overseas Chinese children after school hours,as they did previously.To meet students'multifaceted learning needs,online extra classes teaching,including online Chinese language classes and some online art classes,is increasingly being offered as a supplement to the diversity of teaching activities in Chinese schools in Europe,with the ultimate goal of improving the learning abilities of overseas Chinese children while relieving pressure on teaching resources in schools.Children’s learning self-efficacy in online extracurricular courses has its own uniqueness,which can be considered from three dimensions,including learning confidence,learning ability,and self-assessment ability.This study aims to examine the factors influencing the self-efficacy of overseas Chinese children and to make optimization suggestions for better teaching methods.In search of that,an online questionnaire survey with 127 participants from overseas Chinese children agedtowas collected.The findings indicate that the role of learning confidence in overseas Chinese children outweighs their learning ability and self-assessment ability.Gender and age have a negligible effect on self-efficacy but have an impact on learning confidence.Chinese schools in Europe do not need to show gender differences when conducting classroom activities in online teaching to improve the online self-efficacy of Chinese children,and efforts should also be made to keep the courage of older students to trial and error.Teachers are expected to investigate more aspects of their students'personalities in future classrooms rather than sticking to a consistent and unchanging teaching model.
基金This work was supported by the National Natural Science Foundation of China grant numbers[52072410].
文摘Hf-based carbides are highly desirable candidate materials for oxidizing environments above 2000℃.However,the static oxidation behavior at their potential service temperatures remains unclear.To fill this gap,the static oxidation behavior of(Hf,Ti)C and the effect of Ti substitutions were investigated in air at 2500℃ under an oxygen partial pressure of 4.2 kPa.After oxidation for 2000 s,the thickness of the oxide layer on the surface of(Hf,Ti)C bulk ceramic is reduced by 62.29%compared with that on the HfC monocarbide surface.The dramatic improvement in oxidation resistance is attributed to the unique oxide layer structure consisting of various crystalline oxycarbides,HfO_(2),and carbon.The Ti-rich oxycarbide((Ti,Hf)C_(x)O_(y))dispersed within HfO_(2) formed the major structure of the oxide layer.A coherent boundary with lattice distortion existed at the HfO2/(Ti,Hf)C_(x)O_(y) interface along the(111)crystal plane direction,which served as an effective oxygen diffusion barrier.The Hfrich oxycarbide((Hf,Ti)CxOy)together with(Ti,Hf)C_(x)O_(y),HfO_(2),and precipitated carbon constituted a dense transition layer,ensuring favorable bonding between the oxide layer and the matrix.The Ti content affects the oxidation resistance of(Hf,Ti)C by determining the oxide layer's phase distribution and integrity.
基金supported by the National Natural Science Foun-dation of China(nos.52073299,51902329)Shanghai Sailing Pro-gram(no.22YF1455700)+4 种基金Natural Science Foundation of Shanghai(no.20ZR1465400)Youth Innovation Promotion Association(CAS,no.2022251)T.Cs.and J.D.acknowledge the financial support of projects:VEGA 2/0174/21T.Cs.was supported by the project Strengthecs(no.H2020-MSCA-IF)of the Slovak Academy of SciencesJ.D.gratefully acknowledge the support of ESET and Alexander von Humboldt Foundations.
文摘High-hardness rock-salt structured transitional metal carbides(TMC)are attracting substantial interest as potential next-generation thermal protection materials.However,the intrinsic brittleness of TMC ceramics impedes their performance in aerodynamically harsh environments.In this work,a promising strategy is proposed to introduce plasticity in TaC–HfC solid solutions by manipulating carbon deficiency.The approach combines density-functional theory(DFT)with experiments and takes Pugh's ratio(k)as the criteria.Depletion of carbon atoms in TaC–HfC solid solutions results in the de-localizing of valence electrons,deviation of spatial modulus along different crystal plane directions,and leading to significant elastic anisotropy.The carbon deficient Ta_(0.8)Hf_(0.2)C_(0.8) is predicted to be a‘softer phase’with reduced modulus and Pugh's ratio(k=0.58).A series of Ta1–xHfxCy(x=0.2 and 0.8,y=0.8,0.9,and 1.0)bulk ceramics are experimentally fabricated by an excessive metal alloying method.Trigonal and hexagonal close-packed structured carbides are derived when the carbon deficiency y decreased to 0.7.The indentation modulus drops from 641.8±14.8 GPa for Ta_(0.8)Hf_(0.2)C_(1.0) to 555.8±9.9 GPa for Ta0.8Hf0.2C0.8.The specific stoichiometric composition of Ta_(0.8)Hf_(0.2)C_(0.8) is experimentally verified to possess both plasticity(k=0.41)and ultra-high nanohardness(41.3±1.3 GPa).
文摘Objective:The aim of this study was to evaluate the effects of traditional Chinese exercises (TCEs) on stroke risk factors in patients with pre-hypertension or mild-to-moderate essential hypertension.Methods:We performed searches of seven electronic databases for studies published from their inception until July 2017.We included randomized controlled trials (RCTs) of the effects of TCEs with or without health education on stroke risk factors in patients with prehypertension or mild-to-moderate essential hypertension.Outcomes were independently extracted from each study by two authors and were pooled to determine risk ratios and standardized mean differences.materials-methodsResults:We included 15 RCTs,involving 1272 hypertensive participants.Compared with no intervention,TCEs were associated with a clinically meaningful amelioration of stroke risk factors,including reductions in systolic blood pressure (SBP),diastolic blood pressure (DBP),fasting blood glucose,blood lipids,and waist-to-hip ratio,and improved quality of life.Compared with health education,TCEs reduced SBP but had no effect on DBP.Compared with health education alone,TCEs plus health education resulted in an amelioration of stroke risk factors.No serious adverse events were reported.resultsConclusion:TCEs may be effective alongside health education in ameliorating stroke risk factors in individuals with pre-hypertension or mild-to-moderate essential hypertension.However,the current evidence is insufficient due to poor methodology and lack of adequate safety data.Further rigorously-designed RCTs are warranted.conclusion.
文摘Based on the description of feedback in the literature and the classification of feedback by different scholars,this paper discusses the efficiency and possible issues of the teachers’use of different feedback in the teaching of second language writing.Through interviews with experienced English majors,this paper further demonstrates the importance of teachers'use of feedback in second language writing teaching.At the end of the paper,the author also shows that the combination of different feedback according to specific situations in teaching can better promote the writing proficiency of second language learners.
基金supported by the National Natural Science Foundation of China(22109127)the China Postdoctoral Science Foundation(2021M702666)+1 种基金the Youth Project of"Shaanxi High-level Talents Introduction Plan",the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(2023-TS-02)the"Special Lubrication and Sealing for Aerospace"Shaanxi Provincial Science and Technology Innovation Team(2024RS-CXTD-63)。
文摘Nanoadditives offer a promising way to reduce friction and wear.In this study,an organic-inorganic hybrid material composed of MXene quantum dots(MQDs)and cetyl trimethylammonium bromide decorated covalent organic frameworks(CNUS-2)is successfully constructed via an electrostatic self-assembly strategy.The combination of MQDs and CNUS-2 not only increases the interlayer spacing of NUS-2 but also mitigates the self-aggregation of MQDs,maximizing the advantages of their intrinsic characteristics.Owing to the synergistic lubrication effect of zero-dimensional MQDs and two-dimensional NUS-2,improved lubricity and interfacial bonding ability are realized.In addition,the relative slip between the CNUS-2@MQDs sheets can reduce friction and anti-wear.As expected,different levels of CNUS-2@MQDs effectively boost the tribological properties.The friction coefficient(0.097)and wear volume(1.48×10^(5)µm^(3))of PAO-10 oil are reduced by 46.7%and 92.6%respectively,after the introduction of the 3.0 wt%CNUS-2@MQDs nanocomposite.Furthermore,the abundant oxygen-containing functional groups in CNUS-2 can accelerate the formation of adsorption and tribochemical reaction films,whereas the MQDs can repair worn surfaces,resulting in superior lubrication performance under variable load,temperature,and frequency conditions.This work not only effectively improves lubrication performance by developing a unique CNUS-2@MQDs nanocomposite,but also provides a reference for the design of novel lubricant additives.
