By considering the effect of suspended solid particles in the ordinary equations for two-dimension inviscid incompressible mixing layer, the Rayleigh equation and the modified Rayleigh equation are obtained. And then,...By considering the effect of suspended solid particles in the ordinary equations for two-dimension inviscid incompressible mixing layer, the Rayleigh equation and the modified Rayleigh equation are obtained. And then, by solving the corresponding eigen-value equations with numerical computational method, the relation curves between perturbation frequency and spacial growth rate of the mixing layer for the varying particle loading, ratio of particle velocity to fluid velocity and Stokes number are got. Sever al important conclusions on the effect of suspended solid particles on unstability of the mixing layer are presented in the end by analyzing all the relation curves.展开更多
The unstability of cytoplasmic male sterilities (CMS) of Brassica napus Lwas stud-ied from 1989 to 1992,and the results indicated: 1. The occurrence of trace-pollen plants In sterilematerials was caused by nuclear pol...The unstability of cytoplasmic male sterilities (CMS) of Brassica napus Lwas stud-ied from 1989 to 1992,and the results indicated: 1. The occurrence of trace-pollen plants In sterilematerials was caused by nuclear polygenes of the maintainers; 2. Progenies of partial sterility typeshowed segregation of sterile, partially sterile (with trace pollen )and fertile plants; 3. High andlow temperature CMS lines were crossed and its progenies manifested complex segregation; 4.There was a tendency to increase the fertility with successive selfing of the high temperatureCMS line.展开更多
BACKGROUND Unstable intertrochanteric fractures in elderly patients require effective surgical management,with both cementless bipolar hemiarthroplasty(CBHA)and proximal femoral nail anti-rotation(PFNA)being valid tre...BACKGROUND Unstable intertrochanteric fractures in elderly patients require effective surgical management,with both cementless bipolar hemiarthroplasty(CBHA)and proximal femoral nail anti-rotation(PFNA)being valid treatment options to reduce morbidity and mortality.AIM To evaluate and compare the outcomes of CBHA and PFNA in treatment of unstable intertrochanteric fractures.METHODS A comprehensive search was conducted to identify relevant studies discussing the outcomes of using both CBH and PFNA in treatment of unstable intertrochanteric fractures.Studies published up to January 1,2025 were searched across multiple databases,including PubMed,EMBASE,Scopus,Web of Science,Cochrane Library,and Google Scholar.Full texts of the selected articles were retrieved,reviewed,and independently assessed by the investigators.Discrepancies were resolved by consensus,with any remaining disagreements being arbitrated by a third author.RESULTS This meta-analysis included three studies,all of which were retrospective,involving a total of 240 patients.The follow-up period for participants was at least 12 months.CBHA was associated with significantly higher blood loss compared to PFNA[mean differences(MD):129.14,95%CI(52.51,205.77),P=0.001],though heterogeneity was high(I²=97%).Operative time showed no significant difference initially[MD:6.10,95%CI(-13.34,25.54),P=0.54],but after excluding one study,BHA had longer operative times[MD:21.51,95%CI(18.60,24.41),P<0.00001].Hospital stay and Harris scores showed no significant differences between groups.CBHA facilitated faster progression to weight-bearing[MD:-11.92,95%CI(-22.46,-1.39),P=0.03]and a lower incidence of prosthetic loosening[risk ratio:0.21,95%CI(0.05,0.92),P=0.04].Refracture and thrombus formation rates were comparable between the two groups.CONCLUSION CBHA offers shorter weight-bearing duration and reduced prosthetic loosening but incurs greater blood loss and longer operative times compared to PFNA.Both techniques show comparable functional recovery,hospital stay,refracture,and thrombus risks.Clinical choice should prioritize early mobilization or surgical minimalism,guided by patient needs.Further prospective studies are warranted.展开更多
Pre-injection is a technique that involves injecting grout materials into the ground prior to excavation,with the aim of stabilizing the surrounding rock mass.This paper introduces an analytical closed-form model for ...Pre-injection is a technique that involves injecting grout materials into the ground prior to excavation,with the aim of stabilizing the surrounding rock mass.This paper introduces an analytical closed-form model for determining the ground reaction curve of tunnels in rock masses exhibiting elastic-brittleplastic behavior and adhering to the Mohr-Coulomb failure criterion.The model incorporates the reinforced region created by the pre-injection method.When the rock mass is reinforced through preinjection,plastic regions can form independently in both the natural and injected rock masses.This leads to six distinct modes of the problem.The analytical model presented in this paper considers three possible scenarios for the development of plastic regions.Each scenario comprises four stages,with each stage representing a different mode of the problem.While injecting the rock mass can enhance its strength and stiffness,it may also increase the brittleness of the injected rock mass and create stress concentrations within it,particularly when brittle grouts are used.As a result,this can elevate the risk of rockburst due to unstable failure.The results obtained from the model demonstrate that ductile grout performs exceptionally well in controlling tunnel convergence in rock masses,as it accommodates deformation without sudden failure,even in squeezing rock mass conditions.Conversely,the use of brittle grouts should be approached with caution,particularly in squeezing rock masses,due to their susceptibility to rockburst incidents.展开更多
Background and Objective Inflammation plays a pivotal role in the progression of coronary artery disease(CAD).High-sensitivity C-reactive protein(hsCRP)serves as a well-established biomarker for assessing cardiovascul...Background and Objective Inflammation plays a pivotal role in the progression of coronary artery disease(CAD).High-sensitivity C-reactive protein(hsCRP)serves as a well-established biomarker for assessing cardiovascular inflammation risk.However,the specific intestinal microbiota alteration contributing to increased inflammation remains unclear.Therefore,the present study investigated the correlation between the intestinal microbiota and inflammation in patients with unstable angina(UA).Methods A cohort of 92 patients with UA was recruited for this study.The plasma hsCRP level was measured via a CardioPhase hsCRP assay,fecal samples were collected after admission,and 16S rRNA sequencing was conducted to identify the fecal microbial profile.The participants were classified into two groups according to the median hsCRP level(1.11 mg/L).The composition of the fecal microbiota was compared between patients with hsCRP≥1.11 mg/L and those with hsCRP<1.11 mg/L.Additionally,the correlations between the fecal microbiota and clinical characteristics were analyzed.Results A notable reduction in the relative abundance of Akkermansia was observed in patients with hsCRP≥1.11 mg/L,whereas the diversity of the fecal microbiota was not significantly different between patients with hsCRP≥1.11 mg/L and those with hsCRP<1.11 mg/L.Furthermore,the abundance of Akkermansia was negatively correlated with hsCRP levels.Conclusion This study suggested a significant association between decreased levels of Akkermansia and inflammatory risk in patients with UA.These findings underscore the potential role of the intestinal microbiota in contributing to inflammation in UA patients.Further work is needed on the mechanism by which the microbiota contributes to inflammatory risk.展开更多
As 2025 unfolds,global economic growth remains lackluster,protectionism is intensifying,and key markets are grappling with weak growth prospects and mounting debt burdens.As the external environment grows ever more un...As 2025 unfolds,global economic growth remains lackluster,protectionism is intensifying,and key markets are grappling with weak growth prospects and mounting debt burdens.As the external environment grows ever more uncertain and unstable,China is poised at a pivotal crossroads in its economic transformation.展开更多
BACKGROUND Pedicle screw fixation is frequently used to treat unstable thoracolumbar injuries;however,the rate of instrumentation failure remains considerable.The primary contributing factor leading to instrumentation...BACKGROUND Pedicle screw fixation is frequently used to treat unstable thoracolumbar injuries;however,the rate of instrumentation failure remains considerable.The primary contributing factor leading to instrumentation failure is poor bone quality.On the other hand,some evidence suggests that surgical tactics can influence long-term instrumentation stability.AIM To assess factors that influence the stability of spinal instrumentation in patients with thoracolumbar injuries.METHODS This study is a non-randomized single center ambispective evaluation of 204 consecutive patients(117 men;87 women)with unstable thoracolumbar injuries.All patients underwent either stand-alone or combined with anterior column reconstruction instrumentation.In cases with spinal cord and nerve root injuries,either posterior or anterior decompression were performed.Patients with pedicle screw loosening were identified via computed tomography imaging.Out of those,cases with clinically significant instrumentation failure were registered.RESULTS The rate of pedicle screw loosening detected by computed tomography was inversely correlated with bone radiodensity figures and an increased association with the number of instrumented levels,residual kyphotic deformity,laminectomy,and lumbosacral fixation.Intermediate screws and anterior reconstruction were associated with a clinically relevant decreased risk of pedicle screw loosening development.Either complete or partial posterior fusion within instrumented levels was capable of decreasing instrumentation failure risk,while extensive decompression with laminectomy and at least one-level total facetectomy were associated with an increased risk of instrumentation failure.Anterior decompression does not have a negative impact on instrumentation stability.CONCLUSION Intermediate screws,anterior reconstruction and posterior tension band preservation are associated with decreased rates of instrumentation instability development.Posterior fusion is beneficial in terms of instrumentation failure prevention.展开更多
Due to the coexistence of compressibility,viscosity,and threedimensional effects,laminar flow is difficult to maintain for high-speed boundary layer on complex geometries.The unstable disturbance waves in the boundary...Due to the coexistence of compressibility,viscosity,and threedimensional effects,laminar flow is difficult to maintain for high-speed boundary layer on complex geometries.The unstable disturbance waves in the boundary layer are excited and rapidly increase during the receptivity process,so sufficiently large Reynolds stress causes the basic flow velocity profile to change,and the formation of turbulence is inevitable.展开更多
In this paper,a nonlinear control approach for an unstable networked plant in the presence of actuator and sensor limitations using robust right coprime factorization is proposed.The actuator is limited by upper and l...In this paper,a nonlinear control approach for an unstable networked plant in the presence of actuator and sensor limitations using robust right coprime factorization is proposed.The actuator is limited by upper and lower constraints and the sensor in the feedback loop is subjected to network-induced unknown time-varying delay and noise.With this nonlinear control method,we first employ right coprime factorization based on isomorphism and operator theory to factorize the plant,so that bounded input bounded output(BIBO)stability can be guaranteed.Next,continuous-time generalized predictive control(CGPC)is utilized for the unstable operator of the right coprime factorized plant to guarantee inner stability and enables the closed-loop dynamics of the system with predictive characteristics.Meanwhile,a second-Do F(degrees of freedom)switched controller that satisfies a perturbed Bezout identity and a robustness condition is designed.By using the CGPC controller that possesses predictive behavior and the second-Do F switched stabilizer,the overall stability of the plant subjected to actuator limitations is guaranteed.To address sensor limitations that exist in networked plants in the form of delay and noise which often cause system performance degradation,we implement an identity operator definition in the feedback loop to compensate for these adverse effects.Further,a pre-operator is designed to ensure that the plant output tracks the reference input.Finally,the effectiveness of the proposed design scheme is demonstrated by simulations.展开更多
Convectively unstable processes caused by dense water subsidence are common occurrences in high-latitude oceanic regions,and significantly modulate mass and heat transport and mixing processes in the ocean.An idealize...Convectively unstable processes caused by dense water subsidence are common occurrences in high-latitude oceanic regions,and significantly modulate mass and heat transport and mixing processes in the ocean.An idealized numerical experiment using the large eddy simulation method was conducted to analyze the three-dimensional flow field structure and the mechanism for dense water subsidence.Specifically,a negative salt flux is set at the sea surface,in which salt flux enters the sea surface to simulate the icing and salting-out phenomena that occur at high latitudes.Results show that the mean-state 3D flow field of dense water subsidence exhibits a hollow conical distribution.The horizontal flow field is characterized by a cyclonic vortex that driven primarily by the pressure gradient and influenced by the Coriolis effect.Moreover,the inverse vertical pressure gradient generated by this vortex inhibits the sinking of the plume,leading to its off-axis deflection and the development of an anticyclonic precession.In addition,the impact of rotation on the structure of a sinking plume within a stratified environment is discussed.Both horizontal vortex intensity and cone angle of the hollow cone flow field are increased with increasing rotation rate,resulting in a decrease in the plume’s maximum sinking depth.Variances in rotation direction cause the horizontal vortex and sinking plumes of dense water in the northern and southern hemispheres to rotate in opposite directions.展开更多
Objective:To evaluate and analyze the actual efficacy of percutaneous vertebroplasty in the treatment of old unstable osteoporotic spinal fractures.Methods:From March 2023 to March 2024,46 patients with old unstable o...Objective:To evaluate and analyze the actual efficacy of percutaneous vertebroplasty in the treatment of old unstable osteoporotic spinal fractures.Methods:From March 2023 to March 2024,46 patients with old unstable osteoporotic spinal fractures in our hospital were included in this study.They were divided into the conventional group and the observation group based on treatment differences,with 23 patients in each group.The conventional group received conservative drug therapy,while the observation group underwent percutaneous vertebroplasty.The following indicators were compared and analyzed between the two groups:clinical treatment effect and improvement in physical function indicators.Results:The treatment efficiency of the observation group was 95.65%(22/23),while that of the conventional group was 69.57%(16/23).There was a significant difference between the groups,and the treatment effect of the observation group was significantly better(P<0.05).After treatment,the scores of physical status,daily living ability,functional independence,and life obstacles in the observation group were(89.33±4.08),(88.72±4.08),(90.41±2.89),(72.35±3.22),respectively,while those in the conventional group were(68.54±4.21),(67.42±4.11),(73.48±2.75),(72.35±3.22).There was a significant difference between the groups,and the improvement in physical function indicators in the observation group was more pronounced(P<0.05).Conclusion:For patients with old unstable osteoporotic spinal fractures,the basic value of percutaneous vertebroplasty is significant.It can not only improve clinical efficacy and safety but also promote the gradual recovery of patients'physical function indicators.It is recommended for clinical reference and practical application.展开更多
Understanding the unstable evolution of railway slopes is the premise for preventing slope failure and ensuring the safe operation of trains.However,as two major factors affecting the stability of railway slopes,few s...Understanding the unstable evolution of railway slopes is the premise for preventing slope failure and ensuring the safe operation of trains.However,as two major factors affecting the stability of railway slopes,few scholars have explored the unstable evolution of railway slopes under the joint action of rainfall-vibration.Based on the model test of sandy soil slope,the unstable evolution process of slope under locomotive vibration,rainfall,and rainfall-vibration joint action conditions was simulated in this paper.By comparing and analyzing the variation trends of soil pressure and water content of slope under these conditions,the change laws of pore pressure under the influence of vibration and rainfall were explored.The main control factors affecting the stability of slope structure under the joint action conditions were further defined.Combined with the slope failure phenomena under these three conditions,the causes of slope instability resulting from each leading factor were clarified.Finally,according to the above conclusions,the unstable evolution of the slope under the rainfall-vibration joint action was determined.The test results show that the unstable evolution process of sandy soil slope,under the rainfall-vibration joint action,can be divided into:rainfall erosion cracking,vibration promotion penetrating,and slope instability sliding three stages.In the process of slope unstable evolution,rainfall and vibration play the roles of inducing and promoting slide respectively.In addition,the deep cracks,which are the premise for the formation of the sliding surface,and the violent irregular fluctuation of soil pressure,which reflects the near penetration of the sliding surface,constitute the instability characteristics of the railway slope together.This paper reveals the unstable evolution of sandy soil slopes under the joint action of rainfall-vibration,hoping to provide the theoretical basis for the early warning and prevention technology of railway slopes.展开更多
The abrupt occurrence of the Zhongbao landslide is totally unexpected,resulting in the destruction of local infrastructure and river blockage.To review the deformation history of the Zhongbao landslide and prevent the...The abrupt occurrence of the Zhongbao landslide is totally unexpected,resulting in the destruction of local infrastructure and river blockage.To review the deformation history of the Zhongbao landslide and prevent the threat of secondary disasters,the small baseline subsets(SBAS)technology is applied to process 59 synthetic aperture radar(SAR)images captured from Sentinel-1A satellite.Firstly,the time series deformation of the Zhongbao landslide along the radar line of sight(LOS)direction is calculated by SBAS technology.Then,the projection transformation is conducted to determine the slope displacement.Furthermore,the Hurst exponent of the surface deformation along the two directions is calculated to quantify the hidden deformation development trend and identify the unstable deformation areas.Given the suddenness of the Zhongbao landslide failure,the multi-temporal interferometric synthetic aperture radar(InSAR)technology is the ideal tool to obtain the surface deformation history without any monitoring equipment.The obtained deformation process indicates that the Zhongbao landslide is generally stable with slow creep deformation before failure.Moreover,the Hurst exponent distribution on the landslide surface in different time stages reveals more deformation evolution information of the Zhongbao landslide,with partially unstable areas detected before the failure.Two potential unstable areas after the Zhongbao landslide disaster are revealed by the Hurst exponent distribution and verified by the GNSS monitoring results and deformation mechanism discussion.The method combining SBASInSAR and Hurst exponent proposed in this study could help prevent and control secondary landslide disasters.展开更多
BACKGROUND Coronary stent implantation is usually used to treat unstable angina to alleviate stenosis or occlusion,promoting blood flow restoration and alleviating symptoms such as myocardial ischemia.And postoperativ...BACKGROUND Coronary stent implantation is usually used to treat unstable angina to alleviate stenosis or occlusion,promoting blood flow restoration and alleviating symptoms such as myocardial ischemia.And postoperative cardiac rehabilitation is essential for enhancing recovery and prognosis.Nevertheless,conventional rehabilitation lacks specificity,particularly for elderly patients with multiple comorbidities and poor compliance,rendering it less effective.AIM To investigate the effects of systematic cardiac rehabilitation training in elderly patients with unstable angina following coronary stenting intervention.METHODS A retrospective enrollment was conducted comprising fifty-four elderly patients with unstable angina pectoris who underwent systematic cardiac rehabilitation training after receiving coronary intervention as the rehabilitation group,while fifty-three elderly patients who received basic nursing and rehabilitation guidance measures after coronary intervention were assigned to the control group.Differences in Seattle Angina Questionnaire scores,survival quality(SF-36)scores,cardiopulmonary exercise function assessment index,echocardiographic cardiac function index,and adverse cardiovascular events were compared between the two groups.RESULTS After intervention,the rehabilitation group observed greater VO2 Max,maximum metabolic equivalent,eft ventricular ejection fraction,left ventricular end-diastolic diameter and smaller left ventricular end-systolic diameter.And the rehabilitation group observed greater scores of physical activity limitation,stable angina pectoris,treatment satisfaction,and SF-36 score.The incidence of adverse cardiovascular events in the two groups,showed no significant difference.CONCLUSION Systematic cardiac rehabilitation following coronary stenting in elderly patients with unstable angina pectoris can enhance cardiac function recovery,consequently enhancing both quality of life and cardiopulmonary exercise tolerance.展开更多
BACKGROUND Among the most frequent hip fractures are trochanteric fractures,which usually occur from low-energy trauma like minor falls,especially in older people with osteoporotic bones.AIM To evaluate the treatment ...BACKGROUND Among the most frequent hip fractures are trochanteric fractures,which usually occur from low-energy trauma like minor falls,especially in older people with osteoporotic bones.AIM To evaluate the treatment efficacy of dynamic condylar screws(DCS)and proximal femoral nails(PFN)for unstable intertrochanteric fractures.METHODS To find pertinent randomized controlled trials and retrospective observational studies comparing PFN with DCS for the management of unstable femoral intertrochanteric fractures,a thorough search was carried out.For research studies published between January 1996 and April 2024,PubMed,EMBASE,Scopus,Web of Science,Cochrane Library,and Google Scholar were all searched.The complete texts of the papers were retrieved,vetted,and independently examined by two investigators.Disputes were settled by consensus,and any disagreements that persisted were arbitrated by a third author.RESULTS This study included six articles,comprising a total of 173 patients.Compared to the DCS,the PFN had a shorter operation time[mean difference(MD):-41.7 min,95%confidence interval(95%CI):-63.04 to-20.35,P=0.0001],higher success rates with closed reduction techniques[risk ratio(RR):34.05,95%CI:11.12-104.31,P<0.00001],and required less intraoperative blood transfusion(MD:-1.4 units,95%CI:-1.80 to-1.00,P<0.00001).Additionally,the PFN showed shorter fracture union time(MD:-6.92 wk,95%CI:-10.27 to-3.57,P<0.0001)and a lower incidence of reoperation(RR:0.37,95%CI:0.17-0.82,P=0.01).However,there was no discernible variation regarding hospital stay,implant-related complications,and infections.CONCLUSION Compared to DCS,PFN offers shorter operative times,reduces the blood transfusions requirements,achieves higher closed reduction success,enables faster fracture healing,and lowers reoperation incidence.展开更多
Objective:To analyze the effect of using continuity of care for elderly patients with coronary heart disease(CHD)with unstable angina pectoris(UAP)and its impact on their quality of life.Methods:100 cases of elderly p...Objective:To analyze the effect of using continuity of care for elderly patients with coronary heart disease(CHD)with unstable angina pectoris(UAP)and its impact on their quality of life.Methods:100 cases of elderly patients with CHD with UAP admitted to our hospital from March 2022 to March 2023 were selected and grouped into an observation group and a control group of 50 cases each according to the randomized number table method.The nursing effect and quality of life of the observation group(continuity nursing)and the control group(routine nursing)were compared.Results:The total effective rate of nursing care was 96.00%observation group and 80.00%for the control group,and the differences were significant(χ2=6.061,P<0.05).Patients in the observation group had fewer episodes(1.42±0.21)times/week and a shorter duration(5.46±0.39)min,which were better than the control group(t=3.465,2.973;P<0.05).The depression self-rating depression scale(SDS)score(42.16±6.64)and anxiety self-rating scale(SAS)score(32.26±7.35)in the observation group were lower and the quality of life was higher as compared to that of the control group(P<0.05).Conclusion:Continuous nursing care improved the nursing effect of elderly CHD with UAP patients,promoted the alleviation of UAP symptoms,improved patient mentality,and improved their quality of life.Hence,continuous nursing care possesses significant clinical application value.展开更多
With pursuing high energy density batteries,traditional graphite anode could be unable to meet current needs[1-4].The high-capacity anodes have attracted increasing attention,such as lithium anodes and alloy-type anod...With pursuing high energy density batteries,traditional graphite anode could be unable to meet current needs[1-4].The high-capacity anodes have attracted increasing attention,such as lithium anodes and alloy-type anodes[5-8].Silicon anode,as a high-capacity alloy-type anode(3579 mAh/g),has attracted great attention[9].However,due to its unique electrochemical mechanism,significant changes in volume and morphology during charge/discharge process could lead to the decrease in cycling stability[9,10].Therefore,it is still challenging for silicon anode in tackling volume expansion and unstable interfaces.展开更多
Central venous catheterization(CVC) is an invasive procedure for administering fluids,nutrients,and drugs;monitoring central venous pressure;performing pulmonary artery catheterization;and placing transvenous pacemake...Central venous catheterization(CVC) is an invasive procedure for administering fluids,nutrients,and drugs;monitoring central venous pressure;performing pulmonary artery catheterization;and placing transvenous pacemakers in intensive care units and all specialties,from anesthesia to emergency medicine,for the treatment of trauma and hemodynamically unstable pediatric and adult patients.[1,2]Complications have been observed in more than 15% of patients who underwent CVC.Mechanical,infectious,and thrombotic complications have been reported in 5%–19%,5%–26%,and 2%–26% of patients,respectively.[3] Malposition,on the other hand,is common in subclavian catheter insertion and is usually associated with an initially misplaced guidewire.[4]展开更多
Robotic percutaneous coronary intervention(R-PCI)is a novel technology in which operators can manipulate guidewires and catheter devices in interventional cardiology.This approach provides great benefits to interventi...Robotic percutaneous coronary intervention(R-PCI)is a novel technology in which operators can manipulate guidewires and catheter devices in interventional cardiology.This approach provides great benefits to interventional cardiologists in terms of reducing both radiation exposure and orthopedic injuries.Several large,high-quality cohort studies have confirmed the short-term safety and high technical success rate of R-PCI.However,randomized long-term data are still needed before adopting them as part of standard coronary interventions.Furthermore,tele-stenting for complex coronary lesions has significant potential for R-PCI.We need to overcome the present relevant challenges for its application such as inherent delays,bedside care for unstable patients from R-PCIs to manual PCIs(M-PCIs),incompatibility for a thrombus aspiration catheter and heavily calcified lesions.There is a great future in laboratory workflow teams,3D-printed anatomical models and multiple joint collaborative control algorithms.This narrative review summarizes the latest developments in R-PCI,with a focus on developments in robotic technology,and discusses the current and future potential use of R-PCI in clinical practice globally.展开更多
文摘By considering the effect of suspended solid particles in the ordinary equations for two-dimension inviscid incompressible mixing layer, the Rayleigh equation and the modified Rayleigh equation are obtained. And then, by solving the corresponding eigen-value equations with numerical computational method, the relation curves between perturbation frequency and spacial growth rate of the mixing layer for the varying particle loading, ratio of particle velocity to fluid velocity and Stokes number are got. Sever al important conclusions on the effect of suspended solid particles on unstability of the mixing layer are presented in the end by analyzing all the relation curves.
文摘The unstability of cytoplasmic male sterilities (CMS) of Brassica napus Lwas stud-ied from 1989 to 1992,and the results indicated: 1. The occurrence of trace-pollen plants In sterilematerials was caused by nuclear polygenes of the maintainers; 2. Progenies of partial sterility typeshowed segregation of sterile, partially sterile (with trace pollen )and fertile plants; 3. High andlow temperature CMS lines were crossed and its progenies manifested complex segregation; 4.There was a tendency to increase the fertility with successive selfing of the high temperatureCMS line.
文摘BACKGROUND Unstable intertrochanteric fractures in elderly patients require effective surgical management,with both cementless bipolar hemiarthroplasty(CBHA)and proximal femoral nail anti-rotation(PFNA)being valid treatment options to reduce morbidity and mortality.AIM To evaluate and compare the outcomes of CBHA and PFNA in treatment of unstable intertrochanteric fractures.METHODS A comprehensive search was conducted to identify relevant studies discussing the outcomes of using both CBH and PFNA in treatment of unstable intertrochanteric fractures.Studies published up to January 1,2025 were searched across multiple databases,including PubMed,EMBASE,Scopus,Web of Science,Cochrane Library,and Google Scholar.Full texts of the selected articles were retrieved,reviewed,and independently assessed by the investigators.Discrepancies were resolved by consensus,with any remaining disagreements being arbitrated by a third author.RESULTS This meta-analysis included three studies,all of which were retrospective,involving a total of 240 patients.The follow-up period for participants was at least 12 months.CBHA was associated with significantly higher blood loss compared to PFNA[mean differences(MD):129.14,95%CI(52.51,205.77),P=0.001],though heterogeneity was high(I²=97%).Operative time showed no significant difference initially[MD:6.10,95%CI(-13.34,25.54),P=0.54],but after excluding one study,BHA had longer operative times[MD:21.51,95%CI(18.60,24.41),P<0.00001].Hospital stay and Harris scores showed no significant differences between groups.CBHA facilitated faster progression to weight-bearing[MD:-11.92,95%CI(-22.46,-1.39),P=0.03]and a lower incidence of prosthetic loosening[risk ratio:0.21,95%CI(0.05,0.92),P=0.04].Refracture and thrombus formation rates were comparable between the two groups.CONCLUSION CBHA offers shorter weight-bearing duration and reduced prosthetic loosening but incurs greater blood loss and longer operative times compared to PFNA.Both techniques show comparable functional recovery,hospital stay,refracture,and thrombus risks.Clinical choice should prioritize early mobilization or surgical minimalism,guided by patient needs.Further prospective studies are warranted.
文摘Pre-injection is a technique that involves injecting grout materials into the ground prior to excavation,with the aim of stabilizing the surrounding rock mass.This paper introduces an analytical closed-form model for determining the ground reaction curve of tunnels in rock masses exhibiting elastic-brittleplastic behavior and adhering to the Mohr-Coulomb failure criterion.The model incorporates the reinforced region created by the pre-injection method.When the rock mass is reinforced through preinjection,plastic regions can form independently in both the natural and injected rock masses.This leads to six distinct modes of the problem.The analytical model presented in this paper considers three possible scenarios for the development of plastic regions.Each scenario comprises four stages,with each stage representing a different mode of the problem.While injecting the rock mass can enhance its strength and stiffness,it may also increase the brittleness of the injected rock mass and create stress concentrations within it,particularly when brittle grouts are used.As a result,this can elevate the risk of rockburst due to unstable failure.The results obtained from the model demonstrate that ductile grout performs exceptionally well in controlling tunnel convergence in rock masses,as it accommodates deformation without sudden failure,even in squeezing rock mass conditions.Conversely,the use of brittle grouts should be approached with caution,particularly in squeezing rock masses,due to their susceptibility to rockburst incidents.
基金supported by the National Natural Science Foundation of China(No.82030016,No 82230011 and No.82200533).
文摘Background and Objective Inflammation plays a pivotal role in the progression of coronary artery disease(CAD).High-sensitivity C-reactive protein(hsCRP)serves as a well-established biomarker for assessing cardiovascular inflammation risk.However,the specific intestinal microbiota alteration contributing to increased inflammation remains unclear.Therefore,the present study investigated the correlation between the intestinal microbiota and inflammation in patients with unstable angina(UA).Methods A cohort of 92 patients with UA was recruited for this study.The plasma hsCRP level was measured via a CardioPhase hsCRP assay,fecal samples were collected after admission,and 16S rRNA sequencing was conducted to identify the fecal microbial profile.The participants were classified into two groups according to the median hsCRP level(1.11 mg/L).The composition of the fecal microbiota was compared between patients with hsCRP≥1.11 mg/L and those with hsCRP<1.11 mg/L.Additionally,the correlations between the fecal microbiota and clinical characteristics were analyzed.Results A notable reduction in the relative abundance of Akkermansia was observed in patients with hsCRP≥1.11 mg/L,whereas the diversity of the fecal microbiota was not significantly different between patients with hsCRP≥1.11 mg/L and those with hsCRP<1.11 mg/L.Furthermore,the abundance of Akkermansia was negatively correlated with hsCRP levels.Conclusion This study suggested a significant association between decreased levels of Akkermansia and inflammatory risk in patients with UA.These findings underscore the potential role of the intestinal microbiota in contributing to inflammation in UA patients.Further work is needed on the mechanism by which the microbiota contributes to inflammatory risk.
文摘As 2025 unfolds,global economic growth remains lackluster,protectionism is intensifying,and key markets are grappling with weak growth prospects and mounting debt burdens.As the external environment grows ever more uncertain and unstable,China is poised at a pivotal crossroads in its economic transformation.
基金Supported by AI For Spinal Surgery Planning and Results Assessment Project under the“Priority 2030”Academic Leadership Initiative,No.6.18-01/240724-15.
文摘BACKGROUND Pedicle screw fixation is frequently used to treat unstable thoracolumbar injuries;however,the rate of instrumentation failure remains considerable.The primary contributing factor leading to instrumentation failure is poor bone quality.On the other hand,some evidence suggests that surgical tactics can influence long-term instrumentation stability.AIM To assess factors that influence the stability of spinal instrumentation in patients with thoracolumbar injuries.METHODS This study is a non-randomized single center ambispective evaluation of 204 consecutive patients(117 men;87 women)with unstable thoracolumbar injuries.All patients underwent either stand-alone or combined with anterior column reconstruction instrumentation.In cases with spinal cord and nerve root injuries,either posterior or anterior decompression were performed.Patients with pedicle screw loosening were identified via computed tomography imaging.Out of those,cases with clinically significant instrumentation failure were registered.RESULTS The rate of pedicle screw loosening detected by computed tomography was inversely correlated with bone radiodensity figures and an increased association with the number of instrumented levels,residual kyphotic deformity,laminectomy,and lumbosacral fixation.Intermediate screws and anterior reconstruction were associated with a clinically relevant decreased risk of pedicle screw loosening development.Either complete or partial posterior fusion within instrumented levels was capable of decreasing instrumentation failure risk,while extensive decompression with laminectomy and at least one-level total facetectomy were associated with an increased risk of instrumentation failure.Anterior decompression does not have a negative impact on instrumentation stability.CONCLUSION Intermediate screws,anterior reconstruction and posterior tension band preservation are associated with decreased rates of instrumentation instability development.Posterior fusion is beneficial in terms of instrumentation failure prevention.
文摘Due to the coexistence of compressibility,viscosity,and threedimensional effects,laminar flow is difficult to maintain for high-speed boundary layer on complex geometries.The unstable disturbance waves in the boundary layer are excited and rapidly increase during the receptivity process,so sufficiently large Reynolds stress causes the basic flow velocity profile to change,and the formation of turbulence is inevitable.
文摘In this paper,a nonlinear control approach for an unstable networked plant in the presence of actuator and sensor limitations using robust right coprime factorization is proposed.The actuator is limited by upper and lower constraints and the sensor in the feedback loop is subjected to network-induced unknown time-varying delay and noise.With this nonlinear control method,we first employ right coprime factorization based on isomorphism and operator theory to factorize the plant,so that bounded input bounded output(BIBO)stability can be guaranteed.Next,continuous-time generalized predictive control(CGPC)is utilized for the unstable operator of the right coprime factorized plant to guarantee inner stability and enables the closed-loop dynamics of the system with predictive characteristics.Meanwhile,a second-Do F(degrees of freedom)switched controller that satisfies a perturbed Bezout identity and a robustness condition is designed.By using the CGPC controller that possesses predictive behavior and the second-Do F switched stabilizer,the overall stability of the plant subjected to actuator limitations is guaranteed.To address sensor limitations that exist in networked plants in the form of delay and noise which often cause system performance degradation,we implement an identity operator definition in the feedback loop to compensate for these adverse effects.Further,a pre-operator is designed to ensure that the plant output tracks the reference input.Finally,the effectiveness of the proposed design scheme is demonstrated by simulations.
基金Supported by the National Natural Science Foundation of China(Nos.42250710152,42192562)the Southern Laboratory of Ocean Science and Engineering(Guangdong Zhuhai)(No.SML 2020 SP 007)。
文摘Convectively unstable processes caused by dense water subsidence are common occurrences in high-latitude oceanic regions,and significantly modulate mass and heat transport and mixing processes in the ocean.An idealized numerical experiment using the large eddy simulation method was conducted to analyze the three-dimensional flow field structure and the mechanism for dense water subsidence.Specifically,a negative salt flux is set at the sea surface,in which salt flux enters the sea surface to simulate the icing and salting-out phenomena that occur at high latitudes.Results show that the mean-state 3D flow field of dense water subsidence exhibits a hollow conical distribution.The horizontal flow field is characterized by a cyclonic vortex that driven primarily by the pressure gradient and influenced by the Coriolis effect.Moreover,the inverse vertical pressure gradient generated by this vortex inhibits the sinking of the plume,leading to its off-axis deflection and the development of an anticyclonic precession.In addition,the impact of rotation on the structure of a sinking plume within a stratified environment is discussed.Both horizontal vortex intensity and cone angle of the hollow cone flow field are increased with increasing rotation rate,resulting in a decrease in the plume’s maximum sinking depth.Variances in rotation direction cause the horizontal vortex and sinking plumes of dense water in the northern and southern hemispheres to rotate in opposite directions.
文摘Objective:To evaluate and analyze the actual efficacy of percutaneous vertebroplasty in the treatment of old unstable osteoporotic spinal fractures.Methods:From March 2023 to March 2024,46 patients with old unstable osteoporotic spinal fractures in our hospital were included in this study.They were divided into the conventional group and the observation group based on treatment differences,with 23 patients in each group.The conventional group received conservative drug therapy,while the observation group underwent percutaneous vertebroplasty.The following indicators were compared and analyzed between the two groups:clinical treatment effect and improvement in physical function indicators.Results:The treatment efficiency of the observation group was 95.65%(22/23),while that of the conventional group was 69.57%(16/23).There was a significant difference between the groups,and the treatment effect of the observation group was significantly better(P<0.05).After treatment,the scores of physical status,daily living ability,functional independence,and life obstacles in the observation group were(89.33±4.08),(88.72±4.08),(90.41±2.89),(72.35±3.22),respectively,while those in the conventional group were(68.54±4.21),(67.42±4.11),(73.48±2.75),(72.35±3.22).There was a significant difference between the groups,and the improvement in physical function indicators in the observation group was more pronounced(P<0.05).Conclusion:For patients with old unstable osteoporotic spinal fractures,the basic value of percutaneous vertebroplasty is significant.It can not only improve clinical efficacy and safety but also promote the gradual recovery of patients'physical function indicators.It is recommended for clinical reference and practical application.
基金supported by the Major Research Plan of the National Natural Science Foundation of China(Grant No.42027806)the Key Programme of the Natural Science Foundation of China(Grant No.41630639)National Natural Science Foundation of China General Program(Grant No.42372324).
文摘Understanding the unstable evolution of railway slopes is the premise for preventing slope failure and ensuring the safe operation of trains.However,as two major factors affecting the stability of railway slopes,few scholars have explored the unstable evolution of railway slopes under the joint action of rainfall-vibration.Based on the model test of sandy soil slope,the unstable evolution process of slope under locomotive vibration,rainfall,and rainfall-vibration joint action conditions was simulated in this paper.By comparing and analyzing the variation trends of soil pressure and water content of slope under these conditions,the change laws of pore pressure under the influence of vibration and rainfall were explored.The main control factors affecting the stability of slope structure under the joint action conditions were further defined.Combined with the slope failure phenomena under these three conditions,the causes of slope instability resulting from each leading factor were clarified.Finally,according to the above conclusions,the unstable evolution of the slope under the rainfall-vibration joint action was determined.The test results show that the unstable evolution process of sandy soil slope,under the rainfall-vibration joint action,can be divided into:rainfall erosion cracking,vibration promotion penetrating,and slope instability sliding three stages.In the process of slope unstable evolution,rainfall and vibration play the roles of inducing and promoting slide respectively.In addition,the deep cracks,which are the premise for the formation of the sliding surface,and the violent irregular fluctuation of soil pressure,which reflects the near penetration of the sliding surface,constitute the instability characteristics of the railway slope together.This paper reveals the unstable evolution of sandy soil slopes under the joint action of rainfall-vibration,hoping to provide the theoretical basis for the early warning and prevention technology of railway slopes.
基金support from the National Key R&D Program of China(Grant No.2021YFB3901403)Project supported by graduate research and innovation foundation of Chongqing,China(Grant No.CYS23115)Special project for performance incentive and guidance of scientific research institutions in Chongqing(Grant No.cstc2021jxjl120011)are greatly appreciated。
文摘The abrupt occurrence of the Zhongbao landslide is totally unexpected,resulting in the destruction of local infrastructure and river blockage.To review the deformation history of the Zhongbao landslide and prevent the threat of secondary disasters,the small baseline subsets(SBAS)technology is applied to process 59 synthetic aperture radar(SAR)images captured from Sentinel-1A satellite.Firstly,the time series deformation of the Zhongbao landslide along the radar line of sight(LOS)direction is calculated by SBAS technology.Then,the projection transformation is conducted to determine the slope displacement.Furthermore,the Hurst exponent of the surface deformation along the two directions is calculated to quantify the hidden deformation development trend and identify the unstable deformation areas.Given the suddenness of the Zhongbao landslide failure,the multi-temporal interferometric synthetic aperture radar(InSAR)technology is the ideal tool to obtain the surface deformation history without any monitoring equipment.The obtained deformation process indicates that the Zhongbao landslide is generally stable with slow creep deformation before failure.Moreover,the Hurst exponent distribution on the landslide surface in different time stages reveals more deformation evolution information of the Zhongbao landslide,with partially unstable areas detected before the failure.Two potential unstable areas after the Zhongbao landslide disaster are revealed by the Hurst exponent distribution and verified by the GNSS monitoring results and deformation mechanism discussion.The method combining SBASInSAR and Hurst exponent proposed in this study could help prevent and control secondary landslide disasters.
文摘BACKGROUND Coronary stent implantation is usually used to treat unstable angina to alleviate stenosis or occlusion,promoting blood flow restoration and alleviating symptoms such as myocardial ischemia.And postoperative cardiac rehabilitation is essential for enhancing recovery and prognosis.Nevertheless,conventional rehabilitation lacks specificity,particularly for elderly patients with multiple comorbidities and poor compliance,rendering it less effective.AIM To investigate the effects of systematic cardiac rehabilitation training in elderly patients with unstable angina following coronary stenting intervention.METHODS A retrospective enrollment was conducted comprising fifty-four elderly patients with unstable angina pectoris who underwent systematic cardiac rehabilitation training after receiving coronary intervention as the rehabilitation group,while fifty-three elderly patients who received basic nursing and rehabilitation guidance measures after coronary intervention were assigned to the control group.Differences in Seattle Angina Questionnaire scores,survival quality(SF-36)scores,cardiopulmonary exercise function assessment index,echocardiographic cardiac function index,and adverse cardiovascular events were compared between the two groups.RESULTS After intervention,the rehabilitation group observed greater VO2 Max,maximum metabolic equivalent,eft ventricular ejection fraction,left ventricular end-diastolic diameter and smaller left ventricular end-systolic diameter.And the rehabilitation group observed greater scores of physical activity limitation,stable angina pectoris,treatment satisfaction,and SF-36 score.The incidence of adverse cardiovascular events in the two groups,showed no significant difference.CONCLUSION Systematic cardiac rehabilitation following coronary stenting in elderly patients with unstable angina pectoris can enhance cardiac function recovery,consequently enhancing both quality of life and cardiopulmonary exercise tolerance.
文摘BACKGROUND Among the most frequent hip fractures are trochanteric fractures,which usually occur from low-energy trauma like minor falls,especially in older people with osteoporotic bones.AIM To evaluate the treatment efficacy of dynamic condylar screws(DCS)and proximal femoral nails(PFN)for unstable intertrochanteric fractures.METHODS To find pertinent randomized controlled trials and retrospective observational studies comparing PFN with DCS for the management of unstable femoral intertrochanteric fractures,a thorough search was carried out.For research studies published between January 1996 and April 2024,PubMed,EMBASE,Scopus,Web of Science,Cochrane Library,and Google Scholar were all searched.The complete texts of the papers were retrieved,vetted,and independently examined by two investigators.Disputes were settled by consensus,and any disagreements that persisted were arbitrated by a third author.RESULTS This study included six articles,comprising a total of 173 patients.Compared to the DCS,the PFN had a shorter operation time[mean difference(MD):-41.7 min,95%confidence interval(95%CI):-63.04 to-20.35,P=0.0001],higher success rates with closed reduction techniques[risk ratio(RR):34.05,95%CI:11.12-104.31,P<0.00001],and required less intraoperative blood transfusion(MD:-1.4 units,95%CI:-1.80 to-1.00,P<0.00001).Additionally,the PFN showed shorter fracture union time(MD:-6.92 wk,95%CI:-10.27 to-3.57,P<0.0001)and a lower incidence of reoperation(RR:0.37,95%CI:0.17-0.82,P=0.01).However,there was no discernible variation regarding hospital stay,implant-related complications,and infections.CONCLUSION Compared to DCS,PFN offers shorter operative times,reduces the blood transfusions requirements,achieves higher closed reduction success,enables faster fracture healing,and lowers reoperation incidence.
文摘Objective:To analyze the effect of using continuity of care for elderly patients with coronary heart disease(CHD)with unstable angina pectoris(UAP)and its impact on their quality of life.Methods:100 cases of elderly patients with CHD with UAP admitted to our hospital from March 2022 to March 2023 were selected and grouped into an observation group and a control group of 50 cases each according to the randomized number table method.The nursing effect and quality of life of the observation group(continuity nursing)and the control group(routine nursing)were compared.Results:The total effective rate of nursing care was 96.00%observation group and 80.00%for the control group,and the differences were significant(χ2=6.061,P<0.05).Patients in the observation group had fewer episodes(1.42±0.21)times/week and a shorter duration(5.46±0.39)min,which were better than the control group(t=3.465,2.973;P<0.05).The depression self-rating depression scale(SDS)score(42.16±6.64)and anxiety self-rating scale(SAS)score(32.26±7.35)in the observation group were lower and the quality of life was higher as compared to that of the control group(P<0.05).Conclusion:Continuous nursing care improved the nursing effect of elderly CHD with UAP patients,promoted the alleviation of UAP symptoms,improved patient mentality,and improved their quality of life.Hence,continuous nursing care possesses significant clinical application value.
文摘With pursuing high energy density batteries,traditional graphite anode could be unable to meet current needs[1-4].The high-capacity anodes have attracted increasing attention,such as lithium anodes and alloy-type anodes[5-8].Silicon anode,as a high-capacity alloy-type anode(3579 mAh/g),has attracted great attention[9].However,due to its unique electrochemical mechanism,significant changes in volume and morphology during charge/discharge process could lead to the decrease in cycling stability[9,10].Therefore,it is still challenging for silicon anode in tackling volume expansion and unstable interfaces.
文摘Central venous catheterization(CVC) is an invasive procedure for administering fluids,nutrients,and drugs;monitoring central venous pressure;performing pulmonary artery catheterization;and placing transvenous pacemakers in intensive care units and all specialties,from anesthesia to emergency medicine,for the treatment of trauma and hemodynamically unstable pediatric and adult patients.[1,2]Complications have been observed in more than 15% of patients who underwent CVC.Mechanical,infectious,and thrombotic complications have been reported in 5%–19%,5%–26%,and 2%–26% of patients,respectively.[3] Malposition,on the other hand,is common in subclavian catheter insertion and is usually associated with an initially misplaced guidewire.[4]
文摘Robotic percutaneous coronary intervention(R-PCI)is a novel technology in which operators can manipulate guidewires and catheter devices in interventional cardiology.This approach provides great benefits to interventional cardiologists in terms of reducing both radiation exposure and orthopedic injuries.Several large,high-quality cohort studies have confirmed the short-term safety and high technical success rate of R-PCI.However,randomized long-term data are still needed before adopting them as part of standard coronary interventions.Furthermore,tele-stenting for complex coronary lesions has significant potential for R-PCI.We need to overcome the present relevant challenges for its application such as inherent delays,bedside care for unstable patients from R-PCIs to manual PCIs(M-PCIs),incompatibility for a thrombus aspiration catheter and heavily calcified lesions.There is a great future in laboratory workflow teams,3D-printed anatomical models and multiple joint collaborative control algorithms.This narrative review summarizes the latest developments in R-PCI,with a focus on developments in robotic technology,and discusses the current and future potential use of R-PCI in clinical practice globally.
