末次冰期全球气候波动频繁,影响了哺乳动物的演化和迁移历史。汉中天坑群丰富的地质生物记录是重要的古气候、古环境研究材料,并使用石笋重建了秦巴地区末次冰期的季风演化历史。汉中天坑群考察过程中发现的东方剑齿象化石也为认识晚第...末次冰期全球气候波动频繁,影响了哺乳动物的演化和迁移历史。汉中天坑群丰富的地质生物记录是重要的古气候、古环境研究材料,并使用石笋重建了秦巴地区末次冰期的季风演化历史。汉中天坑群考察过程中发现的东方剑齿象化石也为认识晚第四纪古生物演化历史和生态环境响应提供了重要的参考资料。文章对东方剑齿象样品进行铀系(U-Th)和碳十四(14C)测年,并参考化石上结晶的碳酸钙铀系年龄,判断汉中天坑群天星岩东方剑齿象的生存时代约为27.5kyr BP(kyr=千年;BP=Before the present, present定义为1950年)附近MIS3阶段的DO暖事件。结合已有的石笋氧同位素序列和其他的古气候记录,推测MIS3时期汉中地区气候很可能比现代更温暖湿润,剑齿象从北方迁移到秦岭南部并演化为东方剑齿象,而且主要依靠南方广泛而稳定存在的C_(3)植被为食。到末次盛冰期,气候极端寒冷,东方剑齿象灭绝,而亚洲象因为觅食生态灵活存活至今,生存区间退缩到了西南亚热带地区。展开更多
Objective Helicobacter pylori(HP)infection is associated with non-alcoholic fatty liver disease(NAFLD)and insulin resistance;however,the correlation between HP eradication and NAFLD remains controversial.This systemat...Objective Helicobacter pylori(HP)infection is associated with non-alcoholic fatty liver disease(NAFLD)and insulin resistance;however,the correlation between HP eradication and NAFLD remains controversial.This systematic review and meta-analysis examined the effect of HP treatment on clinical and laboratory parameters in NAFLD patients.Methods We conducted a literature search of the PubMed,Embase,Scopus,and Web of Science databases through Septem-ber 2023 for randomized controlled trials(RCTs)examining the effect of HP treatment on NAFLD patients versus lifestyle changes alone.The primary outcome was the change in steatosis parameters.The secondary endpoints were changes in anthropometric parameters,inflammatory markers(TNF-α),and metabolic parameters(fasting blood glucose,homeostasis model assessment of insulin resistance,AST/ALT,and lipid profile).The random effects model was used to calculate the standardized mean difference(SMD)with associated 95%confidence intervals(CIs)for our desired outcome.Results Four RCTs met our inclusion criteria.A total of 453 patients were included(mean age 42.8 years,58.5%males),228(50.3%)of whom were in the HP eradication group and 225(49.7%)of whom were in the lifestyle modification group.Compared with lifestyle modification alone,HP eradication had a significant effect on reducing liver steatosis and TNF-αlevels(SMD:-0.9;95%CI-14.67,-3.82,I^(2)=0%and SMD:-6.3;95%CI-9.04,-3.56,I^(2)=0%,respectively).No sig-nificant effect on other metabolic parameters was found.Conclusions HP eradication significantly reduced liver steatosis and TNF-αlevels in NAFLD patients.However,HP eradi-cation did not significantly affect other metabolic indices compared to lifestyle changes alone.展开更多
Polymer flooding is an important means of improving oil recovery and is widely used in Daqing,Xinjiang,and Shengli oilfields,China.Different from conventional injection media such as water and gas,viscoelastic polymer...Polymer flooding is an important means of improving oil recovery and is widely used in Daqing,Xinjiang,and Shengli oilfields,China.Different from conventional injection media such as water and gas,viscoelastic polymer solutions exhibit non-Newtonian and nonlinear flow behavior including shear thinning and shear thickening,polymer convection,diffusion,adsorption,retention,inaccessible pore volume,and reduced effective permeability.However,available well test model of polymer flooding wells generally simplifies these characteristics on pressure transient response,which may lead to inaccurate results.This work proposes a novel two-phase numerical well test model to better describe the polymer viscoelasticity and nonlinear flow behavior.Different influence factors that related to near-well blockage during polymer flooding process,including the degree of blockage(inner zone permeability),the extent of blockage(composite radius),and polymer flooding front radius are explored to investigate these impacts on bottom hole pressure responses.Results show that polymer viscoelasticity has a significant impact on the transitional flow segment of type curves,and the effects of near-well formation blockage and polymer concentration distribution on well test curves are very similar.Thus,to accurately interpret the degree of near-well blockage in injection wells,it is essential to first eliminate the influence of polymer viscoelasticity.Finally,a field case is comprehensively analyzed and discussed to illustrate the applicability of the proposed model.展开更多
Background:Over the past 50 years,the incidence of obesity has gradually increased,necessitating investigation into the multifactorial contributors to this disease,including the gut microbiota.Bacteria within the huma...Background:Over the past 50 years,the incidence of obesity has gradually increased,necessitating investigation into the multifactorial contributors to this disease,including the gut microbiota.Bacteria within the human gut microbiome communicate using a density-dependent process known as quorum sensing(QS),in which autoinducer(AI)molecules(e.g.,N-acyl-homoserine lactones[AHLs])are produced to enable bacterial interactions and regulate gene expression.Methods:We aimed to disrupt QS using quorum quenching(QQ)lactonases GcL and SsoPox,which cleave AHL signaling molecules in a taxa-specific manner based on differing enzyme affinities for different substrates.We hypothesized that QQ hinders signals from obesity-associated pathobionts,thereby slowing or preventing obesity.Results:In a murine model of dietinduced obesity,we observed GcL and SsoPox treatments have separate sex-dependent and dose-dependent effects on intestinal community composition and diversity.Notably,male mice given 2 mg/mL SsoPox exhibited significant changes in the relative abundances of gram-negative taxa,including Porphyromonadaceae,Akkermansiaceae,Muribaculaceae,and Bacteroidales(Kruskal-Wallis p<0.001).Additionally,we used covariance matrix network analysis to model bacterial taxa co-occurrence due to QQ enzyme administration.There were more associations among taxa in control mice,particularly among gram-negative bacteria,whereas mice receiving SsoPox had the fewest associations.Conclusions:Overall,our study establishes proof of concept that QQ is a targetable strategy for microbial control in vivo.Further characterization and dosage optimization of QQ enzymes are necessary to harness their therapeutic capability for the treatment of chronic microbial-associated diseases.展开更多
Introduction:Non–muscle-invasive bladder cancer(NMIBC)is a common malignancy worldwide.While Bacillus Calmette-Guérin(BCG)is standard of care for treatment for most patients with high-risk NMIBC,many will either...Introduction:Non–muscle-invasive bladder cancer(NMIBC)is a common malignancy worldwide.While Bacillus Calmette-Guérin(BCG)is standard of care for treatment for most patients with high-risk NMIBC,many will either not respond to BCG initially or will eventually develop BCG-unresponsive disease.A treatment option in BCG-unresponsive disease is nadofaragene firadenovec-vncg(Adstiladrin),a nonreplicating adenoviral vector–based gene therapy approved by the US Food and Drug Administration(FDA)for the treatment of adults with high-risk BCGunresponsive NMIBC with carcinoma in situ with or without papillary tumors.Objective:To review safety outcomes of participants who received the FDA-approved dose of nadofaragene firadenovec(3×10^(11)vp/mL)across phase 2(NCT01687244)and phase 3(NCT02773849)studies.Methods:Data from the phase 2 and phase 3 studies were collected and analyzed.The findings were reported using descriptive statistics to summarize the key outcomes observed across studies.Results:Common adverse events(AEs)among nadofaragene firadenovec recipients were leakage of fluid around the urinary catheter,fatigue,bladder spasm,chills,dysuria,and micturition urgency.Most study drug–related AEs were mild and localized,with no grade 4 or 5 study drug–related AEs observed in either study.Study drug–related AEs were generally transient,with most study drug–related AEs having a median duration of≤2.0 days in the phase 3 study.Discontinuation rates due to study drug–related AEs were low,with none(0%)in the phase 2 study and three(1.9%)in the phase 3 study.No specific postmarketing surveillance was required by the FDA besides routine pharmacovigilance monitoring;no new real-world safety signals have been observed.Conclusion:Nadofaragene firadenovec demonstrated a favorable and tolerable safety profile across its clinical study program,allowing for broad patient selection among those with high-risk BCG-unresponsive NMIBC.展开更多
Women with adult congenital heart disease(CHD)face unique challenges during pregnancy,as gestational cardiovascular(CV)and hemodynamic changes can exacerbate underlying cardiac conditions.While these adaptations are w...Women with adult congenital heart disease(CHD)face unique challenges during pregnancy,as gestational cardiovascular(CV)and hemodynamic changes can exacerbate underlying cardiac conditions.While these adaptations are well tole-rated in women with structurally and functionally normal hearts,they pose sig-nificant risks for those with adult CHD(ACHD),whether repaired,palliated,or with residual defects.Maternal CHD is associated with an increased risk of ad-verse CV events,including stroke,heart failure,arrhythmias,and thromboem-bolic complications during pregnancy and the peripartum period.Effective mana-gement requires a multidisciplinary team,including cardiologists,perinatologists,anesthesiologists,and other skilled care providers.Risk stratification tools such as the modified World Health Organization classification,CARPREG II,and ZA-HARA scores are useful for predicting maternal and fetal outcomes and guiding clinical decision-making.Preconception counseling plays a critical role in asse-ssing individual risks,optimizing cardiac function,and educating patients about potential complications.Future research should prioritize innovative therapies,including targeted pharmacological agents and minimally invasive interventions,alongside improved screening methods to identify high-risk patients before symp-tomatic disease manifests.This review synthesizes current literature on managing pregnant women with ACHD,highlights gaps in clinical practice,and explores future directions to enhance care.Addressing these challenges is essential to improving maternal and fetal outcomes and ensuring comprehensive,patient-centered care throughout the reproductive journey.展开更多
The big underground powerhouse cavern of the China Baihetan hydropower plant is 438m long,34m wide,and 88.7m high.It is cut by a weak interlayer shear zone and its high sidewall poses a huge stability problem.This pap...The big underground powerhouse cavern of the China Baihetan hydropower plant is 438m long,34m wide,and 88.7m high.It is cut by a weak interlayer shear zone and its high sidewall poses a huge stability problem.This paper reports our successful solution of this problem through numerical simulations and a replacement-tunnel scheme in the detailed design stage and close site monitoring in the excavation stage.Particularly,in the detail design stage,mechanical parameters of the shear zone were carefully determined through laboratory experiments and site tests.Then,deformation of the surrounding rocks and the shear zone under high in situ stress conditions was predicted using 3 Dimensional Distinct Element Code(3DEC).Subsequently,a replacement-tunnel scheme was proposed for the treatment on the shear zone to prevent severe unloading relaxation of surrounding rocks.In the construction period,excavation responses were closely monitored on deformations of surrounding rocks and the shear zone.The effect of local cracking in the replacement tunnels on sidewall stability was evaluated using the strength reduction method.These monitoring results were compared with the predicted numerical simulation in the detailed design stage.It is found that the shear zone greatly modified the deformation mode of the cavern surrounding rocks.Without any treatment,rock mass deformation on the downstream sidewall was larger than 125mm and the shearing deformation of the shear zone was 60–70 mm.These preset replacement tunnels can reduce not only the unloading and relaxation of rock masses but also the maximum shearing deformation of the shear zone by 10–20 mm.The predictions by numerical simulation were in good agreement with the monitoring results.The proposed tunnel-replacement scheme can not only restrain the shear zone deformation but also enhance the safety of surrounding rocks and concrete tunnels.This design procedure offers a good reference for interaction between a big underground cavern and a weak layer zone in the future.展开更多
Brittle rock has the mechanical characteristics of a high ratio of uniaxial compressive strength to tensilestrength, brittle-ductile transition, and so on. The mineral meso-structure of brittle rock shows theinterlock...Brittle rock has the mechanical characteristics of a high ratio of uniaxial compressive strength to tensilestrength, brittle-ductile transition, and so on. The mineral meso-structure of brittle rock shows theinterlocking behavior and there are some microcracks between the mineral grains, so it is difficult toanalyze the mechanical characteristics accurately with a regular constitutive model. The previous numericalmodels have some limitations when applied to brittle rock, that they cannot provide sufficientinternal interlocking and are incapable of considering the microcracks. These limitations are addressedby using the updated flat-joint contact model to join notional polygonal particles with an initial gap andincreasing the particle coordination number by adding flat-joint contacts to more particles that arewithin some non-zero distance of one another via the range coefficient contact identification method. Acomparison of experimental and numerical results confirms that the updated flat-jointed model providesa good match with the mechanical properties of brittle rock. In this paper, we investigate the influence ofmineral meso-structure (micro-cracks, range coefficient, and radius multiplier) on the meso-mechanicalproperties of Jinping dolomitic marble via the updated flat-joint contact model under direct-tension testsand compression tests. It is found that the updated model can reproduce the microstructure effect ofbrittle rock and can better simulate the mechanical characteristics of the brittle rock than conventionalmodels, such as high strength ratio, brittle-ductile transition, initial nonlinearity, and different modulusin compression and tension.展开更多
It is with profound respect and gratitude that we dedicate this special issue of the Journal of Environmental Sciences to the memory of Professor Chuanyong Jing,whose outstanding contributions to environmental science...It is with profound respect and gratitude that we dedicate this special issue of the Journal of Environmental Sciences to the memory of Professor Chuanyong Jing,whose outstanding contributions to environmental sciences have advanced the field and continue to resonate with both academia and the broader environmental community.展开更多
In this article,Deng and Song showed compelling evidence on the connection between heart rate variability(HRV)alterations and cancer in 127 cancer patients compared with healthy reference individuals,highlighting auto...In this article,Deng and Song showed compelling evidence on the connection between heart rate variability(HRV)alterations and cancer in 127 cancer patients compared with healthy reference individuals,highlighting autonomic nervous system dysfunction as a significant physiological manifestation in cancer patients.We discussed that the reduced HRV may be associated with cancer treatments,e.g.,operation,chemotherapy and pain control and psychological response such as depression and anxiety related to the affected cancer.A management such as medicine to mood disturbances related to cancer has been shown a benefit to improve HRV in cancer patients.展开更多
Purpose:This study aimed to provide comparative evidence on the effectiveness of various lifestyle interventions on body composition management for preschool and school-aged children.Methods:PubMed(MEDLINE),Embase,CIN...Purpose:This study aimed to provide comparative evidence on the effectiveness of various lifestyle interventions on body composition management for preschool and school-aged children.Methods:PubMed(MEDLINE),Embase,CINAHL,and Web of Science were systematically searched for this network meta-analysis.Randomized controlled studies(RCTs)that included children aged 4-12 years with no physical or mental conditions;performed at least 1 type of lifestyle intervention;reported change in body mass index(BMI),BMI z-score,or body fat percentage(BFP);and were published between January2010 and August 2023 were included.Results:The final analysis included 91 RCTs with aggregate data for 58,649 children.All interventions were categorized into single-arm approaches(physical activity,diet,and behavioral and informational support)and combined arms approaches(bicomponent and multicomponent treatment).Multicomponent treatment showed significant effectiveness on the reduction of BMI(mean deviation(MD)-0.49,95%confidence interval(95%CI):-0.88 to-0.12),BMI z-score(MD=-0.11,95%CI:-0.18 to-0.04),and BFP(MD=-1.69,95%CI:-2.97 to-0.42)compared to the usual care condition.Bicomponent treatment also significantly reduced BMI(MD=-0.28,95%CI:-0.54 to-0.04)and BMI z-score(MD=-0.07,95%CI:-0.12 to-0.02)compared to usual care.Conclusion:Interventions targeting multiple lifestyle components achieved greater reductions in children's BMI and BFP.Among single-component approaches,physical activity engagement emerged as the most effective.These findings should guide practitioners in recommending comprehensive lifestyle modifications for children.Moreover,children with higher initial BMI and body fat levels tend to exhibit more positive responses to lifestyle interventions aimed at managing obesity.展开更多
文摘末次冰期全球气候波动频繁,影响了哺乳动物的演化和迁移历史。汉中天坑群丰富的地质生物记录是重要的古气候、古环境研究材料,并使用石笋重建了秦巴地区末次冰期的季风演化历史。汉中天坑群考察过程中发现的东方剑齿象化石也为认识晚第四纪古生物演化历史和生态环境响应提供了重要的参考资料。文章对东方剑齿象样品进行铀系(U-Th)和碳十四(14C)测年,并参考化石上结晶的碳酸钙铀系年龄,判断汉中天坑群天星岩东方剑齿象的生存时代约为27.5kyr BP(kyr=千年;BP=Before the present, present定义为1950年)附近MIS3阶段的DO暖事件。结合已有的石笋氧同位素序列和其他的古气候记录,推测MIS3时期汉中地区气候很可能比现代更温暖湿润,剑齿象从北方迁移到秦岭南部并演化为东方剑齿象,而且主要依靠南方广泛而稳定存在的C_(3)植被为食。到末次盛冰期,气候极端寒冷,东方剑齿象灭绝,而亚洲象因为觅食生态灵活存活至今,生存区间退缩到了西南亚热带地区。
文摘Objective Helicobacter pylori(HP)infection is associated with non-alcoholic fatty liver disease(NAFLD)and insulin resistance;however,the correlation between HP eradication and NAFLD remains controversial.This systematic review and meta-analysis examined the effect of HP treatment on clinical and laboratory parameters in NAFLD patients.Methods We conducted a literature search of the PubMed,Embase,Scopus,and Web of Science databases through Septem-ber 2023 for randomized controlled trials(RCTs)examining the effect of HP treatment on NAFLD patients versus lifestyle changes alone.The primary outcome was the change in steatosis parameters.The secondary endpoints were changes in anthropometric parameters,inflammatory markers(TNF-α),and metabolic parameters(fasting blood glucose,homeostasis model assessment of insulin resistance,AST/ALT,and lipid profile).The random effects model was used to calculate the standardized mean difference(SMD)with associated 95%confidence intervals(CIs)for our desired outcome.Results Four RCTs met our inclusion criteria.A total of 453 patients were included(mean age 42.8 years,58.5%males),228(50.3%)of whom were in the HP eradication group and 225(49.7%)of whom were in the lifestyle modification group.Compared with lifestyle modification alone,HP eradication had a significant effect on reducing liver steatosis and TNF-αlevels(SMD:-0.9;95%CI-14.67,-3.82,I^(2)=0%and SMD:-6.3;95%CI-9.04,-3.56,I^(2)=0%,respectively).No sig-nificant effect on other metabolic parameters was found.Conclusions HP eradication significantly reduced liver steatosis and TNF-αlevels in NAFLD patients.However,HP eradi-cation did not significantly affect other metabolic indices compared to lifestyle changes alone.
基金supported by the National Natural Science Foundation of China(52104049)the Young Elite Scientist Sponsorship Program by Beijing Association for Science and Technology(BYESS2023262)。
文摘Polymer flooding is an important means of improving oil recovery and is widely used in Daqing,Xinjiang,and Shengli oilfields,China.Different from conventional injection media such as water and gas,viscoelastic polymer solutions exhibit non-Newtonian and nonlinear flow behavior including shear thinning and shear thickening,polymer convection,diffusion,adsorption,retention,inaccessible pore volume,and reduced effective permeability.However,available well test model of polymer flooding wells generally simplifies these characteristics on pressure transient response,which may lead to inaccurate results.This work proposes a novel two-phase numerical well test model to better describe the polymer viscoelasticity and nonlinear flow behavior.Different influence factors that related to near-well blockage during polymer flooding process,including the degree of blockage(inner zone permeability),the extent of blockage(composite radius),and polymer flooding front radius are explored to investigate these impacts on bottom hole pressure responses.Results show that polymer viscoelasticity has a significant impact on the transitional flow segment of type curves,and the effects of near-well formation blockage and polymer concentration distribution on well test curves are very similar.Thus,to accurately interpret the degree of near-well blockage in injection wells,it is essential to first eliminate the influence of polymer viscoelasticity.Finally,a field case is comprehensively analyzed and discussed to illustrate the applicability of the proposed model.
基金Biotechnology Institute and the MnDrive initiative(to MHE)。
文摘Background:Over the past 50 years,the incidence of obesity has gradually increased,necessitating investigation into the multifactorial contributors to this disease,including the gut microbiota.Bacteria within the human gut microbiome communicate using a density-dependent process known as quorum sensing(QS),in which autoinducer(AI)molecules(e.g.,N-acyl-homoserine lactones[AHLs])are produced to enable bacterial interactions and regulate gene expression.Methods:We aimed to disrupt QS using quorum quenching(QQ)lactonases GcL and SsoPox,which cleave AHL signaling molecules in a taxa-specific manner based on differing enzyme affinities for different substrates.We hypothesized that QQ hinders signals from obesity-associated pathobionts,thereby slowing or preventing obesity.Results:In a murine model of dietinduced obesity,we observed GcL and SsoPox treatments have separate sex-dependent and dose-dependent effects on intestinal community composition and diversity.Notably,male mice given 2 mg/mL SsoPox exhibited significant changes in the relative abundances of gram-negative taxa,including Porphyromonadaceae,Akkermansiaceae,Muribaculaceae,and Bacteroidales(Kruskal-Wallis p<0.001).Additionally,we used covariance matrix network analysis to model bacterial taxa co-occurrence due to QQ enzyme administration.There were more associations among taxa in control mice,particularly among gram-negative bacteria,whereas mice receiving SsoPox had the fewest associations.Conclusions:Overall,our study establishes proof of concept that QQ is a targetable strategy for microbial control in vivo.Further characterization and dosage optimization of QQ enzymes are necessary to harness their therapeutic capability for the treatment of chronic microbial-associated diseases.
基金This work was supported by Ferring Pharmaceuticals Inc.
文摘Introduction:Non–muscle-invasive bladder cancer(NMIBC)is a common malignancy worldwide.While Bacillus Calmette-Guérin(BCG)is standard of care for treatment for most patients with high-risk NMIBC,many will either not respond to BCG initially or will eventually develop BCG-unresponsive disease.A treatment option in BCG-unresponsive disease is nadofaragene firadenovec-vncg(Adstiladrin),a nonreplicating adenoviral vector–based gene therapy approved by the US Food and Drug Administration(FDA)for the treatment of adults with high-risk BCGunresponsive NMIBC with carcinoma in situ with or without papillary tumors.Objective:To review safety outcomes of participants who received the FDA-approved dose of nadofaragene firadenovec(3×10^(11)vp/mL)across phase 2(NCT01687244)and phase 3(NCT02773849)studies.Methods:Data from the phase 2 and phase 3 studies were collected and analyzed.The findings were reported using descriptive statistics to summarize the key outcomes observed across studies.Results:Common adverse events(AEs)among nadofaragene firadenovec recipients were leakage of fluid around the urinary catheter,fatigue,bladder spasm,chills,dysuria,and micturition urgency.Most study drug–related AEs were mild and localized,with no grade 4 or 5 study drug–related AEs observed in either study.Study drug–related AEs were generally transient,with most study drug–related AEs having a median duration of≤2.0 days in the phase 3 study.Discontinuation rates due to study drug–related AEs were low,with none(0%)in the phase 2 study and three(1.9%)in the phase 3 study.No specific postmarketing surveillance was required by the FDA besides routine pharmacovigilance monitoring;no new real-world safety signals have been observed.Conclusion:Nadofaragene firadenovec demonstrated a favorable and tolerable safety profile across its clinical study program,allowing for broad patient selection among those with high-risk BCG-unresponsive NMIBC.
文摘Women with adult congenital heart disease(CHD)face unique challenges during pregnancy,as gestational cardiovascular(CV)and hemodynamic changes can exacerbate underlying cardiac conditions.While these adaptations are well tole-rated in women with structurally and functionally normal hearts,they pose sig-nificant risks for those with adult CHD(ACHD),whether repaired,palliated,or with residual defects.Maternal CHD is associated with an increased risk of ad-verse CV events,including stroke,heart failure,arrhythmias,and thromboem-bolic complications during pregnancy and the peripartum period.Effective mana-gement requires a multidisciplinary team,including cardiologists,perinatologists,anesthesiologists,and other skilled care providers.Risk stratification tools such as the modified World Health Organization classification,CARPREG II,and ZA-HARA scores are useful for predicting maternal and fetal outcomes and guiding clinical decision-making.Preconception counseling plays a critical role in asse-ssing individual risks,optimizing cardiac function,and educating patients about potential complications.Future research should prioritize innovative therapies,including targeted pharmacological agents and minimally invasive interventions,alongside improved screening methods to identify high-risk patients before symp-tomatic disease manifests.This review synthesizes current literature on managing pregnant women with ACHD,highlights gaps in clinical practice,and explores future directions to enhance care.Addressing these challenges is essential to improving maternal and fetal outcomes and ensuring comprehensive,patient-centered care throughout the reproductive journey.
基金Program of China Three Gorges Corporation,Grant/Award Number:BHT 0679-1。
文摘The big underground powerhouse cavern of the China Baihetan hydropower plant is 438m long,34m wide,and 88.7m high.It is cut by a weak interlayer shear zone and its high sidewall poses a huge stability problem.This paper reports our successful solution of this problem through numerical simulations and a replacement-tunnel scheme in the detailed design stage and close site monitoring in the excavation stage.Particularly,in the detail design stage,mechanical parameters of the shear zone were carefully determined through laboratory experiments and site tests.Then,deformation of the surrounding rocks and the shear zone under high in situ stress conditions was predicted using 3 Dimensional Distinct Element Code(3DEC).Subsequently,a replacement-tunnel scheme was proposed for the treatment on the shear zone to prevent severe unloading relaxation of surrounding rocks.In the construction period,excavation responses were closely monitored on deformations of surrounding rocks and the shear zone.The effect of local cracking in the replacement tunnels on sidewall stability was evaluated using the strength reduction method.These monitoring results were compared with the predicted numerical simulation in the detailed design stage.It is found that the shear zone greatly modified the deformation mode of the cavern surrounding rocks.Without any treatment,rock mass deformation on the downstream sidewall was larger than 125mm and the shearing deformation of the shear zone was 60–70 mm.These preset replacement tunnels can reduce not only the unloading and relaxation of rock masses but also the maximum shearing deformation of the shear zone by 10–20 mm.The predictions by numerical simulation were in good agreement with the monitoring results.The proposed tunnel-replacement scheme can not only restrain the shear zone deformation but also enhance the safety of surrounding rocks and concrete tunnels.This design procedure offers a good reference for interaction between a big underground cavern and a weak layer zone in the future.
基金funding support from the National Natural Science Foundation of China(NSFC,Grant No.51428902)the China Scholarship Council(CSC,Grant No.202306270120).
文摘Brittle rock has the mechanical characteristics of a high ratio of uniaxial compressive strength to tensilestrength, brittle-ductile transition, and so on. The mineral meso-structure of brittle rock shows theinterlocking behavior and there are some microcracks between the mineral grains, so it is difficult toanalyze the mechanical characteristics accurately with a regular constitutive model. The previous numericalmodels have some limitations when applied to brittle rock, that they cannot provide sufficientinternal interlocking and are incapable of considering the microcracks. These limitations are addressedby using the updated flat-joint contact model to join notional polygonal particles with an initial gap andincreasing the particle coordination number by adding flat-joint contacts to more particles that arewithin some non-zero distance of one another via the range coefficient contact identification method. Acomparison of experimental and numerical results confirms that the updated flat-jointed model providesa good match with the mechanical properties of brittle rock. In this paper, we investigate the influence ofmineral meso-structure (micro-cracks, range coefficient, and radius multiplier) on the meso-mechanicalproperties of Jinping dolomitic marble via the updated flat-joint contact model under direct-tension testsand compression tests. It is found that the updated model can reproduce the microstructure effect ofbrittle rock and can better simulate the mechanical characteristics of the brittle rock than conventionalmodels, such as high strength ratio, brittle-ductile transition, initial nonlinearity, and different modulusin compression and tension.
文摘It is with profound respect and gratitude that we dedicate this special issue of the Journal of Environmental Sciences to the memory of Professor Chuanyong Jing,whose outstanding contributions to environmental sciences have advanced the field and continue to resonate with both academia and the broader environmental community.
文摘In this article,Deng and Song showed compelling evidence on the connection between heart rate variability(HRV)alterations and cancer in 127 cancer patients compared with healthy reference individuals,highlighting autonomic nervous system dysfunction as a significant physiological manifestation in cancer patients.We discussed that the reduced HRV may be associated with cancer treatments,e.g.,operation,chemotherapy and pain control and psychological response such as depression and anxiety related to the affected cancer.A management such as medicine to mood disturbances related to cancer has been shown a benefit to improve HRV in cancer patients.
文摘Purpose:This study aimed to provide comparative evidence on the effectiveness of various lifestyle interventions on body composition management for preschool and school-aged children.Methods:PubMed(MEDLINE),Embase,CINAHL,and Web of Science were systematically searched for this network meta-analysis.Randomized controlled studies(RCTs)that included children aged 4-12 years with no physical or mental conditions;performed at least 1 type of lifestyle intervention;reported change in body mass index(BMI),BMI z-score,or body fat percentage(BFP);and were published between January2010 and August 2023 were included.Results:The final analysis included 91 RCTs with aggregate data for 58,649 children.All interventions were categorized into single-arm approaches(physical activity,diet,and behavioral and informational support)and combined arms approaches(bicomponent and multicomponent treatment).Multicomponent treatment showed significant effectiveness on the reduction of BMI(mean deviation(MD)-0.49,95%confidence interval(95%CI):-0.88 to-0.12),BMI z-score(MD=-0.11,95%CI:-0.18 to-0.04),and BFP(MD=-1.69,95%CI:-2.97 to-0.42)compared to the usual care condition.Bicomponent treatment also significantly reduced BMI(MD=-0.28,95%CI:-0.54 to-0.04)and BMI z-score(MD=-0.07,95%CI:-0.12 to-0.02)compared to usual care.Conclusion:Interventions targeting multiple lifestyle components achieved greater reductions in children's BMI and BFP.Among single-component approaches,physical activity engagement emerged as the most effective.These findings should guide practitioners in recommending comprehensive lifestyle modifications for children.Moreover,children with higher initial BMI and body fat levels tend to exhibit more positive responses to lifestyle interventions aimed at managing obesity.
