Let M be a compact n-manifold of positive sectional curvature.We will review classical results on the fundamental group of M,a motivation on the c(n)-cyclic conjecture that the fundamental group of M contains a cyclic...Let M be a compact n-manifold of positive sectional curvature.We will review classical results on the fundamental group of M,a motivation on the c(n)-cyclic conjecture that the fundamental group of M contains a cyclic subgroup of index bounded above by c(n),a constant depending only on n,and we will survey partial results(up to date)on the c(n)-cyclic conjecture.展开更多
The western slope of the Songliao Basin is a gently dipping monoclinal slope featured by stratum overlap, gradual change of stratum inclination and limited fault development, which formed during basin depression inter...The western slope of the Songliao Basin is a gently dipping monoclinal slope featured by stratum overlap, gradual change of stratum inclination and limited fault development, which formed during basin depression interrupted by a tectonic inversion stage. Structure, sedimentation and reser- voir characteristics show that the development of the slope and its sand bodies＇ depositional genesis de- termined the types, distribution and evolution of traps. Up-dip wedge-out traps in distributary channels, lenticular traps in distal sand bars and sand sheets in the delta front are the main lithologic trap types and usually have thin reservoir beds, small areas, and are distributed in clusters and belts. The episode of tectonic inversion led to the formation of structural traps and combination traps. The combination traps are characterized by large numbers of thin oil-bearing beds occurring along fold belts. Matching axial directions of distributary channel sand bodies in delta fronts with channel morphology during the period between deposition of sand bodies and sealing by an unconformity above is the key to the search for large scale traps in a simple slope area.展开更多
We study two-lane totally asymmetric simple exclusion processes(TASEPs)with an intersection.Monte Carlo simulations show that only symmetric phases exist in the system.To verify the existence of asymmetric phases,we c...We study two-lane totally asymmetric simple exclusion processes(TASEPs)with an intersection.Monte Carlo simulations show that only symmetric phases exist in the system.To verify the existence of asymmetric phases,we carry out a cluster mean-field analysis.Analytical results show that the densities of the two upstream segments of the intersection site are always equal,which indicates that the system is not in asymmetric phases.It demonstrates that the spontaneous symmetry breaking does not exist in the system.The density profiles and the boundaries of the symmetric phases are also investigated.We find that the cluster mean-field analysis shows better agreement with simulations than the simple mean-field analysis where the correlation of sites is ignored.展开更多
A complex optical model potential modified by the concept of bonded atom, which takes into consideration the overlapping effect of electron clouds, is employed to calculate the total cross sections for electrons scatt...A complex optical model potential modified by the concept of bonded atom, which takes into consideration the overlapping effect of electron clouds, is employed to calculate the total cross sections for electrons scattering from simple molecules （SO2, H2S, OCS, CS2 and SO3） containing the larger atom, sulfur, at 30-5000eV by using the additivity rule model at Hartree-Fock level. The quantitative molecular total cross section results are compared with those obtained in experiments and other calculations wherever available, and good agreement is obtained. It is shown that the additivity rule model together with the complex optical model potential modified by the concept of bonded atom can give the results closer to the experiments than the one unmodified by it. So, the introduction of bonded-atom concept in complex optical model potential betters the accuracy of the total cross section calculations of electrons from the molecules containing the larger atom, sulfur.展开更多
This paper studies two-lane asymmetric simple exclusion processes(ASEPs)with an intersection.In the upstream segments of the intersection,one particle can move to the next site with rate 1 if the site is empty,and the...This paper studies two-lane asymmetric simple exclusion processes(ASEPs)with an intersection.In the upstream segments of the intersection,one particle can move to the next site with rate 1 if the site is empty,and the other particle can move forward with rate p in the sites of downstream segments.The parameter p can represent the rate of slowing of motion,and the parameter is introduced to investigate spontaneous symmetry breaking(SSB)phenomenon.Extensive Monte Carlo simulations are carried out.It is shown that three symmetric phases exist and the SSB does not exist in the system.Simple mean field approach in which correlation of sites is ignored is firstly adopted to analyze the system,and the system is divided into four independent segments.It is found that the analytical results deviate from the simulation ones,especially when p is small.In addition,the inexsitence of SSB can only be explained qualitatively.Motivated by this,we carry out the cluster mean field analysis in which correlation of five sites is considered.It is shown that densities of the two upstream segments are equal,which demonstrates that the SSB does not exist.It is also shown that,as expected,the cluster mean field analysis performs much better than the simple mean field analysis.展开更多
To overcome the limitations of low efficiency and reliance on manual processes in the measurement of geometric parameters for bridge prefabricated components,a method based on deep learning and computer vision is deve...To overcome the limitations of low efficiency and reliance on manual processes in the measurement of geometric parameters for bridge prefabricated components,a method based on deep learning and computer vision is developed to identify the geometric parameters.The study utilizes a common precast element for highway bridges as the research subject.First,edge feature points of the bridge component section are extracted from images of the precast component cross-sections by combining the Canny operator with mathematical morphology.Subsequently,a deep learning model is developed to identify the geometric parameters of the precast components using the extracted edge coordinates from the images as input and the predefined control parameters of the bridge section as output.A dataset is generated by varying the control parameters and noise levels for model training.Finally,field measurements are conducted to validate the accuracy of the developed method.The results indicate that the developed method effectively identifies the geometric parameters of bridge precast components,with an error rate maintained within 5%.展开更多
Radar cross section(RCS)plays a critical role in modeling target scattering characteristics and enhancing the precision of target detection and localization in integrated sensing and communication(ISAC)systems.This pa...Radar cross section(RCS)plays a critical role in modeling target scattering characteristics and enhancing the precision of target detection and localization in integrated sensing and communication(ISAC)systems.This paper investigates the human body RCS at 26 GHz via multiangle channel measurements under different clothing conditions.Based on calibrated electromagnetic(EM)parameters,the RCS characteristics of the human body in far-field conditions are analyzed using ray-tracing(RT)simulations.Some suggestions for the design of ISAC systems are also discussed.The results provide a solid theoretical foundation and practical reference for the modeling of target scattering characteristics for ISAC channels.展开更多
BACKGROUND Intrathecal bupivacaine is the traditional anesthetic drug used in spinal anesthesia for caesarean sections(CSs),but ropivacaine has emerged as a potential alter-native.This meta-analysis compares the effic...BACKGROUND Intrathecal bupivacaine is the traditional anesthetic drug used in spinal anesthesia for caesarean sections(CSs),but ropivacaine has emerged as a potential alter-native.This meta-analysis compares the efficacy and safety of intrathecal hyper-baric bupivacaine vs hyperbaric ropivacaine for cesarean sections.AIM To systematically evaluate and compare the efficacy and safety of intrathecal hyperbaric bupivacaine and hyperbaric ropivacaine for spinal anesthesia in CSs.METHODS A thorough search of electronic databases was carried out to find pertinent randomized controlled trials(RCTs)comparing intrathecal hyperbaric ropi-vacaine and hyperbaric bupivacaine during CSs.PubMed,Cochrane database,Google Scholar,and Scopus were searched,and papers from January 2000 to January 2024 were deemed eligible and filtered using predetermined inclusion and exclusion criteria.Studies were assessed for methodological quality,and data were extracted for time to adequate anesthesia(sensory and motor blockade),duration of sensory and motor block,hemodynamic changes and side effect profile.The standardized mean difference with 95%CI was used for continuous data.Dichotomous variables were assessed using the Mantel-Haenszel test and the random effect model to compute the odds ratio.RESULTS Total 8 RCTs were selected from a pool of 119 search results for meta-analysis.The meta-analysis evaluated pooled effect sizes and assessed heterogeneity among the studies.The primary objective was to compare key outcomes to identify any significant variances in efficacy and safety profiles between two local anesthetics.The analysis revealed that the difference in the onset of sensory blockade between the two local anesthetics was statistically insignificant(P=0.1586).However,the onset of motor blockade appeared to be faster with bupivacaine(P=0.03589).Additionally,the regression of sensory and motor blockade occurred earlier in the ropivacaine group.Furthermore,the duration of the first analgesic effect was shorter with a significance level of P<0.05.Regarding side effects profile,including hypotension,nausea,and shivering,the study did not observe any significant differences between the two groups.CONCLUSION This meta-analysis offers insights into the effectiveness and safety of hyperbaric bupivacaine vs ropivacaine for cesarean sections.Hyperbaric ropivacaine had a comparable safety profile and faster regression of sensory and motor blockade than hyperbaric bupivacaine,perhaps aiding early mobilization of parturient and facilitating mother-child bonding.Choosing ropivacaine may offer benefits beyond efficacy for cesarean section patients and short surgical procedures.展开更多
Plant roots are widely known to provide mechanical reinforcement to soils against shearing and further increase slope stability.However,whether roots provide reinforcement to loess cyclic re-sistance and how various f...Plant roots are widely known to provide mechanical reinforcement to soils against shearing and further increase slope stability.However,whether roots provide reinforcement to loess cyclic re-sistance and how various factors affect roots reinforcement during seismic loading have rarely been studied.The objective is to conduct a series of cyclic direct simple shear tests and DEM numerical simulation to investigate the cyclic behaviour of rooted loess.The effects of initial static shear stress and loading frequency on the cyclic resistance of root-soil composites were first investigated.After that,cyclic direct simple shear simulations at constant volume were carried out based on the discrete element method(PFC^(3D))to investigate the effects of root geome-try,mechanical traits and root-soil bond strength on the cyclic strength of rooted loess.It was discovered that the roots could effectively improve the cyclic resistance of loess.The cyclic resistance of the root-soil composite decreases with the increase of the initial shear stress,then increases,and improves with the increase of the frequency.The simulation result show that increases in root elastic modulus and root-soil interfacial bond strength can all enhance the cyclic resistance of root-soil composites,and the maximum cyclic resistance of the root-soil composite was obtained when the initial inclination angle of the root system was 90°.展开更多
Background: Cesarean sections have become increasingly prevalent in both developed and developing nations. Nevertheless, postoperative complications, including surgical site infections (SSIs), remain a substantial con...Background: Cesarean sections have become increasingly prevalent in both developed and developing nations. Nevertheless, postoperative complications, including surgical site infections (SSIs), remain a substantial concern that contributes to heightened morbidity and mortality. This study is designed to evaluate the frequency and key determining factors associated with surgical site infections following cesarean section procedures in a tertiary care hospital in Bangladesh. Materials and Methods: This observational cross-sectional study, conducted at the Gynecology Department of Dhaka Medical College Hospital, involved 100 patients aged 15 - 45 who had cesarean deliveries. Data was collected during hospitalization and post-discharge and analyzed to determine the prevalence and relationship between socio-demographic characteristics and surgical site infection. Results: Among the study participants, 14% developed surgical site infections following cesarean operations. More than half of these patients were under the age of 25, with a mean age of 24.45 ± 4.44 years. Surgical site infections were more prevalent in individuals over 30 years old (P-value Conclusion: Post-cesarean surgical site infections are notably prevalent among the participants in this study. Several risk factors have been identified, including age, body mass index (BMI), socioeconomic status, anemia, preterm delivery, personal hygiene practices, regular menstrual cycles, and adherence to antenatal check-ups. The implementation of an effective awareness program, coupled with updated antibiotic protocols, is crucial for significantly reducing the incidence of these infections.展开更多
Tissue clearing combined with high-resolution confocal imaging is a cutting-edge approach for dissecting the three-dimensional(3D)architecture of tissues and deciphering cellular spatial interactions under physiologic...Tissue clearing combined with high-resolution confocal imaging is a cutting-edge approach for dissecting the three-dimensional(3D)architecture of tissues and deciphering cellular spatial interactions under physiological and pathological conditions.Deciphering the spatial interaction of leptin receptor-expressing(LepR^(+))stromal cells with other compartments in the bone marrow is crucial for a deeper understanding of the stem cell niche and the skeletal tissue.In this study,we introduce an optimized protocol for the 3D analysis of skeletal tissues,enabling the visualization of hematopoietic and stromal cells,especially LepR+stromal cells,within optically cleared bone hemisections.Our method preserves the 3D tissue architecture and is extendable to other hematopoietic sites such as calvaria and vertebrae.The protocol entails tissue fixation,decalcification,and cryosectioning to reveal the marrow cavity.Completed within approximately 12 days,this process yields highly transparent tissues that maintain genetically encoded or antibody-stained fluorescent signals.The bone hemisections are compatible with diverse antibody labeling strategies.Confocal microscopy of these transparent samples allows for qualitative and quantitative image analysis using Aivia or Bitplane Imaris software,assessing a spectrum of parameters.With proper storage,the fluorescent signal in the stained and cleared bone hemisections remains intact for at least 2–3 months.This protocol is robust,straightforward to implement,and highly reproducible,offering a valuable tool for tissue architecture and cellular interaction studies.展开更多
Background:Acupuncture has shown potential therapeutic benefits for individuals with simple obesity.However,some researchers argue that some of the effectiveness of acupuncture may be due to the placebo response.Objec...Background:Acupuncture has shown potential therapeutic benefits for individuals with simple obesity.However,some researchers argue that some of the effectiveness of acupuncture may be due to the placebo response.Objective:To understand the placebo response of acupuncture treatment in simple obesity,a systematic review and meta-analysis was designed based on the comparison between sham acupuncture before and after treatment.Search strategy:Eight databases(Pub Med,Web of Science,Cochrane Library,Embase,China National Knowledge Infrastructure,Wanfang Database,China Biology Medicine Database,and Chinese Scientific Journals Database)were searched from inception to August 1,2023.The Me SH search terms comprised obesity and acupuncture.Inclusion criteria:Randomized controlled trials(RCTs)using sham or placebo acupuncture as a control in treating obesity were enrolled.Data extraction and analysis:Two researchers independently extracted data,and the results were crosschecked after completion.Each RCT’s detailed sham/placebo acupuncture treatment protocol was assessed according to the SHam Acupuncture REporting guidelines.The revised Cochrane risk-of-bias tool for randomized trials and the Grading of Recommendations Assessment,Development,and Evaluation(GRADE)system were used to determine the risk of bias and quality of evidence,respectively.Body mass index(BMI)was defined as the primary outcome.Anthropometric parameters and laboratory test parameters related to obesity were defined as secondary outcomes.We used standardized mean difference(SMD)with 95%confidence interval(CI)to calculate treatment effects of outcomes.Results:Fifteen RCTs with a total of 1250 patients were included.The BMI significantly decreased after treatment in the sham acupuncture group compared to baseline(SMD 0.37,95%CI 0.09–0.66;I2=81%,random model;P<0.01).Treatment duration(P=0.02)and other interventions significantly impacted the placebo response rate(P=0.00).Conclusion:The placebo response of sham acupuncture was strong in the RCTs for simple obesity,and the effect sizes differed between various outcomes.The treatment duration and other interventions emerged as potential influencing factors for the placebo response of sham acupuncture.展开更多
Acute pulmonary edema is a leading cause of death in patients with preeclampsia.The authors reported a case of a pregnant woman at 25 weeks of gestation with severe preeclampsia complicated by pulmonary edema,who requ...Acute pulmonary edema is a leading cause of death in patients with preeclampsia.The authors reported a case of a pregnant woman at 25 weeks of gestation with severe preeclampsia complicated by pulmonary edema,who required an emergency cesarean section,posing a significant challenge to the anesthesiologist.The patient had developed Type 1 respiratory failure and needed supplemental oxygen with high-flow nasal oxygen.Due to contraindications for neuraxial anesthesia,the cesarean section was performed under general anesthesia.After induction of anesthesia,the patient’s hypoxemia worsened.Eventually,after treatment with fluid restriction,diuretics,and albumin,oxygenation improved gradually,and the procedure was performed successfully.Both the patient and the newborn had a good prognosis.展开更多
Mg alloy often undergoes shear deformation during industrial processing.While its anisotropy and tension-compression asymmetry have been thoroughly studied under uniaxial loading,the understanding for shear loading is...Mg alloy often undergoes shear deformation during industrial processing.While its anisotropy and tension-compression asymmetry have been thoroughly studied under uniaxial loading,the understanding for shear loading is still lacking.This study employed a rolled AZ31B plate with typical basal texture to investigate the shear behaviors.Positive and negative simple shear experiments were performed at different angles in the transverse plane,whereby the visco-plastic self-consistent model was calibrated to reveal the deformation mechanisms and predict the mechanical responses at various orientations.Positive-negative shear asymmetry is present because extension twinning preferentially operates in one shear direction but is suppressed in the opposite direction.Simple shear induces multiple twin variants,thus impedes twin growth and slows the consumption of matrix,as compared to in-plane compression.For slip dominated simple shear,the interaction between loading-induced rigid body rotation and slip-induced crystal rotation produces distinct hardening behaviors,namely orthogonally asymmetric mechanical responses at complementary loading angles,which is largely absent in uniaxial loading.Finally,simulation results verify that positive-negative shear asymmetry appears only when the deviatoric normal stress on the sheet plane is non-zero.Positive-negative shear asymmetry persists except for the conditions of shear plane parallel to sheet plane,or shear direction parallel or perpendicular to rolling direction.展开更多
Objective:The objective of this study is to determine the effect of nurse-led instructional video(NLIV)on anxiety,satisfaction,and recovery among mothers admitted for cesarean section(CS).Materials and Methods:A quasi...Objective:The objective of this study is to determine the effect of nurse-led instructional video(NLIV)on anxiety,satisfaction,and recovery among mothers admitted for cesarean section(CS).Materials and Methods:A quasi-experimental design was carried out on the mothers scheduled for CS.Eighty participants were selected by a purposive sampling technique,which were divided(40 participants in each group)into an experimental group and a control group.Nurse-led informational video(NLIV)was shown to the experimental group,and routine care was provided for the control group.Modified hospital anxiety scale(HADS),scale for measuring maternal satisfaction in cesarean birth,and obstetric quality of recovery following cesarean delivery were used to assess anxiety,satisfaction,and recovery.Results:Both the experimental and control groups showed significant reductions in anxiety by the first postintervention day(P<0.001),with the experimental group experiencing a greater mean reduction(mean difference[MD]=4.37)than the control group(MD=3.35)but the intergroup difference was not statistically significant(P>0.05).The experimental group reported significantly higher satisfaction scores(175.55±9.42)on the 3rd postoperative day compared to the control group(151.93±14.89;P<0.001).Similarly,the experimental group’s recovery scores(79.90±6.24)were considerably higher than those of the control group(62.45±15.18;P<0.001).On the 3rd postintervention day,satisfaction was significantly associated with age(P<0.001),and recovery with gravidity(P<0.05).Conclusions:NLIV can be used in the preoperative period to reduce anxiety related to CS and to improve satisfaction and recovery after the CS.展开更多
文摘Let M be a compact n-manifold of positive sectional curvature.We will review classical results on the fundamental group of M,a motivation on the c(n)-cyclic conjecture that the fundamental group of M contains a cyclic subgroup of index bounded above by c(n),a constant depending only on n,and we will survey partial results(up to date)on the c(n)-cyclic conjecture.
基金sponsored by the University Science Fund of China (No.292013124)
文摘The western slope of the Songliao Basin is a gently dipping monoclinal slope featured by stratum overlap, gradual change of stratum inclination and limited fault development, which formed during basin depression interrupted by a tectonic inversion stage. Structure, sedimentation and reser- voir characteristics show that the development of the slope and its sand bodies＇ depositional genesis de- termined the types, distribution and evolution of traps. Up-dip wedge-out traps in distributary channels, lenticular traps in distal sand bars and sand sheets in the delta front are the main lithologic trap types and usually have thin reservoir beds, small areas, and are distributed in clusters and belts. The episode of tectonic inversion led to the formation of structural traps and combination traps. The combination traps are characterized by large numbers of thin oil-bearing beds occurring along fold belts. Matching axial directions of distributary channel sand bodies in delta fronts with channel morphology during the period between deposition of sand bodies and sealing by an unconformity above is the key to the search for large scale traps in a simple slope area.
基金Project supported by the National Natural Science Foundation of China(Grant No.11802003).
文摘We study two-lane totally asymmetric simple exclusion processes(TASEPs)with an intersection.Monte Carlo simulations show that only symmetric phases exist in the system.To verify the existence of asymmetric phases,we carry out a cluster mean-field analysis.Analytical results show that the densities of the two upstream segments of the intersection site are always equal,which indicates that the system is not in asymmetric phases.It demonstrates that the spontaneous symmetry breaking does not exist in the system.The density profiles and the boundaries of the symmetric phases are also investigated.We find that the cluster mean-field analysis shows better agreement with simulations than the simple mean-field analysis where the correlation of sites is ignored.
基金Project supported by the National Natural Science Foundation of China （Grant No 10174019）.
文摘A complex optical model potential modified by the concept of bonded atom, which takes into consideration the overlapping effect of electron clouds, is employed to calculate the total cross sections for electrons scattering from simple molecules （SO2, H2S, OCS, CS2 and SO3） containing the larger atom, sulfur, at 30-5000eV by using the additivity rule model at Hartree-Fock level. The quantitative molecular total cross section results are compared with those obtained in experiments and other calculations wherever available, and good agreement is obtained. It is shown that the additivity rule model together with the complex optical model potential modified by the concept of bonded atom can give the results closer to the experiments than the one unmodified by it. So, the introduction of bonded-atom concept in complex optical model potential betters the accuracy of the total cross section calculations of electrons from the molecules containing the larger atom, sulfur.
基金Project supported by the National Natural Science Foundation of China(Grant No.11802003).
文摘This paper studies two-lane asymmetric simple exclusion processes(ASEPs)with an intersection.In the upstream segments of the intersection,one particle can move to the next site with rate 1 if the site is empty,and the other particle can move forward with rate p in the sites of downstream segments.The parameter p can represent the rate of slowing of motion,and the parameter is introduced to investigate spontaneous symmetry breaking(SSB)phenomenon.Extensive Monte Carlo simulations are carried out.It is shown that three symmetric phases exist and the SSB does not exist in the system.Simple mean field approach in which correlation of sites is ignored is firstly adopted to analyze the system,and the system is divided into four independent segments.It is found that the analytical results deviate from the simulation ones,especially when p is small.In addition,the inexsitence of SSB can only be explained qualitatively.Motivated by this,we carry out the cluster mean field analysis in which correlation of five sites is considered.It is shown that densities of the two upstream segments are equal,which demonstrates that the SSB does not exist.It is also shown that,as expected,the cluster mean field analysis performs much better than the simple mean field analysis.
基金The National Natural Science Foundation of China(No.52338011,52378291)Young Elite Scientists Sponsorship Program by CAST(No.2022-2024QNRC0101).
文摘To overcome the limitations of low efficiency and reliance on manual processes in the measurement of geometric parameters for bridge prefabricated components,a method based on deep learning and computer vision is developed to identify the geometric parameters.The study utilizes a common precast element for highway bridges as the research subject.First,edge feature points of the bridge component section are extracted from images of the precast component cross-sections by combining the Canny operator with mathematical morphology.Subsequently,a deep learning model is developed to identify the geometric parameters of the precast components using the extracted edge coordinates from the images as input and the predefined control parameters of the bridge section as output.A dataset is generated by varying the control parameters and noise levels for model training.Finally,field measurements are conducted to validate the accuracy of the developed method.The results indicate that the developed method effectively identifies the geometric parameters of bridge precast components,with an error rate maintained within 5%.
基金supported by the National Natural Science Foundation of China under Grant No.62271043Ministry of Education of China under Grant No.8091B032123Beijing Natural Science Foundation under Grant No.L212029。
文摘Radar cross section(RCS)plays a critical role in modeling target scattering characteristics and enhancing the precision of target detection and localization in integrated sensing and communication(ISAC)systems.This paper investigates the human body RCS at 26 GHz via multiangle channel measurements under different clothing conditions.Based on calibrated electromagnetic(EM)parameters,the RCS characteristics of the human body in far-field conditions are analyzed using ray-tracing(RT)simulations.Some suggestions for the design of ISAC systems are also discussed.The results provide a solid theoretical foundation and practical reference for the modeling of target scattering characteristics for ISAC channels.
文摘BACKGROUND Intrathecal bupivacaine is the traditional anesthetic drug used in spinal anesthesia for caesarean sections(CSs),but ropivacaine has emerged as a potential alter-native.This meta-analysis compares the efficacy and safety of intrathecal hyper-baric bupivacaine vs hyperbaric ropivacaine for cesarean sections.AIM To systematically evaluate and compare the efficacy and safety of intrathecal hyperbaric bupivacaine and hyperbaric ropivacaine for spinal anesthesia in CSs.METHODS A thorough search of electronic databases was carried out to find pertinent randomized controlled trials(RCTs)comparing intrathecal hyperbaric ropi-vacaine and hyperbaric bupivacaine during CSs.PubMed,Cochrane database,Google Scholar,and Scopus were searched,and papers from January 2000 to January 2024 were deemed eligible and filtered using predetermined inclusion and exclusion criteria.Studies were assessed for methodological quality,and data were extracted for time to adequate anesthesia(sensory and motor blockade),duration of sensory and motor block,hemodynamic changes and side effect profile.The standardized mean difference with 95%CI was used for continuous data.Dichotomous variables were assessed using the Mantel-Haenszel test and the random effect model to compute the odds ratio.RESULTS Total 8 RCTs were selected from a pool of 119 search results for meta-analysis.The meta-analysis evaluated pooled effect sizes and assessed heterogeneity among the studies.The primary objective was to compare key outcomes to identify any significant variances in efficacy and safety profiles between two local anesthetics.The analysis revealed that the difference in the onset of sensory blockade between the two local anesthetics was statistically insignificant(P=0.1586).However,the onset of motor blockade appeared to be faster with bupivacaine(P=0.03589).Additionally,the regression of sensory and motor blockade occurred earlier in the ropivacaine group.Furthermore,the duration of the first analgesic effect was shorter with a significance level of P<0.05.Regarding side effects profile,including hypotension,nausea,and shivering,the study did not observe any significant differences between the two groups.CONCLUSION This meta-analysis offers insights into the effectiveness and safety of hyperbaric bupivacaine vs ropivacaine for cesarean sections.Hyperbaric ropivacaine had a comparable safety profile and faster regression of sensory and motor blockade than hyperbaric bupivacaine,perhaps aiding early mobilization of parturient and facilitating mother-child bonding.Choosing ropivacaine may offer benefits beyond efficacy for cesarean section patients and short surgical procedures.
文摘Plant roots are widely known to provide mechanical reinforcement to soils against shearing and further increase slope stability.However,whether roots provide reinforcement to loess cyclic re-sistance and how various factors affect roots reinforcement during seismic loading have rarely been studied.The objective is to conduct a series of cyclic direct simple shear tests and DEM numerical simulation to investigate the cyclic behaviour of rooted loess.The effects of initial static shear stress and loading frequency on the cyclic resistance of root-soil composites were first investigated.After that,cyclic direct simple shear simulations at constant volume were carried out based on the discrete element method(PFC^(3D))to investigate the effects of root geome-try,mechanical traits and root-soil bond strength on the cyclic strength of rooted loess.It was discovered that the roots could effectively improve the cyclic resistance of loess.The cyclic resistance of the root-soil composite decreases with the increase of the initial shear stress,then increases,and improves with the increase of the frequency.The simulation result show that increases in root elastic modulus and root-soil interfacial bond strength can all enhance the cyclic resistance of root-soil composites,and the maximum cyclic resistance of the root-soil composite was obtained when the initial inclination angle of the root system was 90°.
文摘Background: Cesarean sections have become increasingly prevalent in both developed and developing nations. Nevertheless, postoperative complications, including surgical site infections (SSIs), remain a substantial concern that contributes to heightened morbidity and mortality. This study is designed to evaluate the frequency and key determining factors associated with surgical site infections following cesarean section procedures in a tertiary care hospital in Bangladesh. Materials and Methods: This observational cross-sectional study, conducted at the Gynecology Department of Dhaka Medical College Hospital, involved 100 patients aged 15 - 45 who had cesarean deliveries. Data was collected during hospitalization and post-discharge and analyzed to determine the prevalence and relationship between socio-demographic characteristics and surgical site infection. Results: Among the study participants, 14% developed surgical site infections following cesarean operations. More than half of these patients were under the age of 25, with a mean age of 24.45 ± 4.44 years. Surgical site infections were more prevalent in individuals over 30 years old (P-value Conclusion: Post-cesarean surgical site infections are notably prevalent among the participants in this study. Several risk factors have been identified, including age, body mass index (BMI), socioeconomic status, anemia, preterm delivery, personal hygiene practices, regular menstrual cycles, and adherence to antenatal check-ups. The implementation of an effective awareness program, coupled with updated antibiotic protocols, is crucial for significantly reducing the incidence of these infections.
基金National Natural Science Foundation of China(grant number 82272563 to B.S.)National Science and Technology Major Project of the Ministry of Science and Technology of China(grant number 2023ZD0501202 to B.S.)+4 种基金institutional grants allocated to the National Institute of Biological Sciences,Beijing(NIBS)from the Chinese Ministry of Science and Technology,Beijing Municipal Commission of Science and Technology,and Tsinghua Universitythe support from China Pharmaceutical University(grant number 3150140001 to S.F.)National Natural Science Foundation of China(grant numbers 82203653 to S.F.,82371957 to L.W.,and 82371956 to X.C.)Beijing Municipal Public Welfare Development and Reform Pilot Project for Medical Research Institutes(grant number JYY2023-8 to X.C.)Research Grants Council of University Grants Committee Hong Kong(grant numbers 14113723,14108720,14121721,14202920,N_CUHK472/22,C7030-18G,T13-402/17-N,and AoE/M-402/20)。
文摘Tissue clearing combined with high-resolution confocal imaging is a cutting-edge approach for dissecting the three-dimensional(3D)architecture of tissues and deciphering cellular spatial interactions under physiological and pathological conditions.Deciphering the spatial interaction of leptin receptor-expressing(LepR^(+))stromal cells with other compartments in the bone marrow is crucial for a deeper understanding of the stem cell niche and the skeletal tissue.In this study,we introduce an optimized protocol for the 3D analysis of skeletal tissues,enabling the visualization of hematopoietic and stromal cells,especially LepR+stromal cells,within optically cleared bone hemisections.Our method preserves the 3D tissue architecture and is extendable to other hematopoietic sites such as calvaria and vertebrae.The protocol entails tissue fixation,decalcification,and cryosectioning to reveal the marrow cavity.Completed within approximately 12 days,this process yields highly transparent tissues that maintain genetically encoded or antibody-stained fluorescent signals.The bone hemisections are compatible with diverse antibody labeling strategies.Confocal microscopy of these transparent samples allows for qualitative and quantitative image analysis using Aivia or Bitplane Imaris software,assessing a spectrum of parameters.With proper storage,the fluorescent signal in the stained and cleared bone hemisections remains intact for at least 2–3 months.This protocol is robust,straightforward to implement,and highly reproducible,offering a valuable tool for tissue architecture and cellular interaction studies.
基金supported by grants from the National Natural Science Foundation of China(82405192)the Capital’s Funds for Health Improvement and Research(CFH 2022-2-20213,CFH 2022-1-2021)+1 种基金the project of"Friendship Seed Plan"Talent Project of Beijing Friendship Hospital,Capital Medical University(YYZZ202333)Beijing key project of major disease by Chinese medicine and Western medicine(Fatty liver,No.2023BJSZDYNJBXTGG-017)。
文摘Background:Acupuncture has shown potential therapeutic benefits for individuals with simple obesity.However,some researchers argue that some of the effectiveness of acupuncture may be due to the placebo response.Objective:To understand the placebo response of acupuncture treatment in simple obesity,a systematic review and meta-analysis was designed based on the comparison between sham acupuncture before and after treatment.Search strategy:Eight databases(Pub Med,Web of Science,Cochrane Library,Embase,China National Knowledge Infrastructure,Wanfang Database,China Biology Medicine Database,and Chinese Scientific Journals Database)were searched from inception to August 1,2023.The Me SH search terms comprised obesity and acupuncture.Inclusion criteria:Randomized controlled trials(RCTs)using sham or placebo acupuncture as a control in treating obesity were enrolled.Data extraction and analysis:Two researchers independently extracted data,and the results were crosschecked after completion.Each RCT’s detailed sham/placebo acupuncture treatment protocol was assessed according to the SHam Acupuncture REporting guidelines.The revised Cochrane risk-of-bias tool for randomized trials and the Grading of Recommendations Assessment,Development,and Evaluation(GRADE)system were used to determine the risk of bias and quality of evidence,respectively.Body mass index(BMI)was defined as the primary outcome.Anthropometric parameters and laboratory test parameters related to obesity were defined as secondary outcomes.We used standardized mean difference(SMD)with 95%confidence interval(CI)to calculate treatment effects of outcomes.Results:Fifteen RCTs with a total of 1250 patients were included.The BMI significantly decreased after treatment in the sham acupuncture group compared to baseline(SMD 0.37,95%CI 0.09–0.66;I2=81%,random model;P<0.01).Treatment duration(P=0.02)and other interventions significantly impacted the placebo response rate(P=0.00).Conclusion:The placebo response of sham acupuncture was strong in the RCTs for simple obesity,and the effect sizes differed between various outcomes.The treatment duration and other interventions emerged as potential influencing factors for the placebo response of sham acupuncture.
文摘Acute pulmonary edema is a leading cause of death in patients with preeclampsia.The authors reported a case of a pregnant woman at 25 weeks of gestation with severe preeclampsia complicated by pulmonary edema,who required an emergency cesarean section,posing a significant challenge to the anesthesiologist.The patient had developed Type 1 respiratory failure and needed supplemental oxygen with high-flow nasal oxygen.Due to contraindications for neuraxial anesthesia,the cesarean section was performed under general anesthesia.After induction of anesthesia,the patient’s hypoxemia worsened.Eventually,after treatment with fluid restriction,diuretics,and albumin,oxygenation improved gradually,and the procedure was performed successfully.Both the patient and the newborn had a good prognosis.
基金supports of the National Key Research and Development Program of China(Grant No.2023YFB3710900)the National Natural Science Foundation of China(Grant Nos.52071211 and 52071208)。
文摘Mg alloy often undergoes shear deformation during industrial processing.While its anisotropy and tension-compression asymmetry have been thoroughly studied under uniaxial loading,the understanding for shear loading is still lacking.This study employed a rolled AZ31B plate with typical basal texture to investigate the shear behaviors.Positive and negative simple shear experiments were performed at different angles in the transverse plane,whereby the visco-plastic self-consistent model was calibrated to reveal the deformation mechanisms and predict the mechanical responses at various orientations.Positive-negative shear asymmetry is present because extension twinning preferentially operates in one shear direction but is suppressed in the opposite direction.Simple shear induces multiple twin variants,thus impedes twin growth and slows the consumption of matrix,as compared to in-plane compression.For slip dominated simple shear,the interaction between loading-induced rigid body rotation and slip-induced crystal rotation produces distinct hardening behaviors,namely orthogonally asymmetric mechanical responses at complementary loading angles,which is largely absent in uniaxial loading.Finally,simulation results verify that positive-negative shear asymmetry appears only when the deviatoric normal stress on the sheet plane is non-zero.Positive-negative shear asymmetry persists except for the conditions of shear plane parallel to sheet plane,or shear direction parallel or perpendicular to rolling direction.
文摘Objective:The objective of this study is to determine the effect of nurse-led instructional video(NLIV)on anxiety,satisfaction,and recovery among mothers admitted for cesarean section(CS).Materials and Methods:A quasi-experimental design was carried out on the mothers scheduled for CS.Eighty participants were selected by a purposive sampling technique,which were divided(40 participants in each group)into an experimental group and a control group.Nurse-led informational video(NLIV)was shown to the experimental group,and routine care was provided for the control group.Modified hospital anxiety scale(HADS),scale for measuring maternal satisfaction in cesarean birth,and obstetric quality of recovery following cesarean delivery were used to assess anxiety,satisfaction,and recovery.Results:Both the experimental and control groups showed significant reductions in anxiety by the first postintervention day(P<0.001),with the experimental group experiencing a greater mean reduction(mean difference[MD]=4.37)than the control group(MD=3.35)but the intergroup difference was not statistically significant(P>0.05).The experimental group reported significantly higher satisfaction scores(175.55±9.42)on the 3rd postoperative day compared to the control group(151.93±14.89;P<0.001).Similarly,the experimental group’s recovery scores(79.90±6.24)were considerably higher than those of the control group(62.45±15.18;P<0.001).On the 3rd postintervention day,satisfaction was significantly associated with age(P<0.001),and recovery with gravidity(P<0.05).Conclusions:NLIV can be used in the preoperative period to reduce anxiety related to CS and to improve satisfaction and recovery after the CS.
