Background Tourniquets used during total knee arthroplasty may lead to many complications. The aim of this study was to determine perioperative blood loss and its clinical relevance in total knee replacement surgery a...Background Tourniquets used during total knee arthroplasty may lead to many complications. The aim of this study was to determine perioperative blood loss and its clinical relevance in total knee replacement surgery after applying a tourniquet.Methods From June 2009 to October 2009, 60 consecutive patients who underwent routine total knee arthroplasty were randomly divided into two groups and were treated with or without a tourniquet （30 patients/group）. There were no significant differences in patient baseline characteristics between the two groups. We compared the two groups of patients in terms of intra- and postoperative bleeding, invisible or visible bleeding, and total blood loss.Results None of the patients showed poor wound healing, lower extremity deep venous thrombosis or other complications. The amount of blood loss during surgery was lower in the tourniquet group than in the control group （P〈0.01）. However, postoperative visible bleeding （P 〈0.05） and occult bleeding （P 〈0.05） were significantly greater in the toumiquet group than in the control group. There was no significant difference in the total amount of blood loss between the two groups （P 〉0.05）.Conclusions Tourniquet can reduce bleeding during total knee replacement surgery, but is associated with greater visible and invisible blood loss.展开更多
Background:Aspirin has demonstrated safety and efficacy for venous thromboembolism(VTE)prophylaxis following total hip arthroplasty(THA);however,inconsistent dose regimens have been reported in the literature.This stu...Background:Aspirin has demonstrated safety and efficacy for venous thromboembolism(VTE)prophylaxis following total hip arthroplasty(THA);however,inconsistent dose regimens have been reported in the literature.This study aimed to evaluate and compare the safety and efficacy of 100 mg aspirin twice daily with rivaroxaban in VTE prophylaxis following THA.Methods:Patients undergoing elective unilateral primary THA between January 2019 and January 2020 were prospectively enrolled in the study and randomly allocated to receive 5 weeks of VTE prophylaxis with either oral enteric-coated aspirin(100 mg twice daily)or rivaroxaban(10 mg once daily).Medication safety and efficacy were comprehensively evaluated through symptomatic VTE incidence,deep vein thrombosis(DVT)on Doppler ultrasonography,total blood loss(TBL),laboratory bloodwork,Harris hip score(HHS),post-operative recovery,and the incidence of other complications.Results:We included 70 patients in this study;34 and 36 were allocated to receive aspirin and rivaroxaban prophylaxis,respectively.No cases of symptomatic VTE occurred in this study.The DVT rate on Doppler ultrasonography in the aspirin group was not significantly different from that in the rivaroxaban group(8.8%vs.8.3%,χ^(2)=0.01,P=0.91),confirming the non-inferiority of aspirin for DVT prophylaxis(χ^(2)=2.29,P=0.01).The calculated TBL in the aspirin group(944.9 mL[658.5-1137.8 mL])was similar to that in the rivaroxaban group(978.3 mL[747.4-1740.6mL])(χ^(2)=1.55,P=0.12).However,there were no significant inter-group differences in HHS at post-operative day(POD)30(Aspirin:81.0[78.8-83.0],Rivaroxaban:81.0[79.3-83.0],χ^(2)=0.43,P=0.67)and POD 90(Aspirin:90.0[89.0-92.0],Rivaroxaban:91.5[88.3-92.8],χ^(2)=0.77,P=0.44),the incidence of bleeding events(2.9%vs.8.3%,χ^(2)=0.96,P=0.33),or gastrointestinal complications(2.9%vs.5.6%,χ^(2)=1.13,P=0.29).Conclusion:In terms of safety and efficacy,the prophylactic use of 100 mg aspirin twice daily was not statistically different from that of rivaroxaban in preventing展开更多
This paper discusses the influence of various volute designs on volute overall performance for a certain centrifu- gal compressor with both vaned and vaneless diffuser. Firstly, based on a free vortex flow pattern and...This paper discusses the influence of various volute designs on volute overall performance for a certain centrifu- gal compressor with both vaned and vaneless diffuser. Firstly, based on a free vortex flow pattern and the assumption of a circumferentially uniform flow at the design condition, a corrected method for volute design is adopted. By means of this method, corresponding to five geometric parameters affecting the volute overall performance, ten volute cases are designed. Secondly, the numerical simulation is employed and the detailed flow field and losses in different volutes with different geometric parameters are analyzed. The numerical investigation reveals that in all of the five geometric parameters, the radial location of the cross-section has the strongest influence on the performance of the volute. The non-uniform volute inlet formed by the upward vaned diffuser outlet flow is another important factor. Finally a relatively better value of D1/D2 is concluded.展开更多
To overcome the limitations posed by three-dimensional corner separation,this paper proposes a novel flow control technology known as passive End-Wall(EW)self-adaptive jet.Two single EW slotted schemes(EWS1 and EWS2),...To overcome the limitations posed by three-dimensional corner separation,this paper proposes a novel flow control technology known as passive End-Wall(EW)self-adaptive jet.Two single EW slotted schemes(EWS1 and EWS2),alongside a combined(COM)scheme featuring double EW slots,were investigated.The results reveal that the EW slot,driven by pressure differentials between the pressure and suction sides,can generate an adaptive jet with escalating velocity as the operational load increases.This high-speed jet effectively re-excites the local low-energy fluid,thereby mitigating the corner separation.Notably,the EWS1 slot,positioned near the blade leading edge,exhibits relatively low jet velocities at negative incidence angles,causing jet separation and exacerbating the corner separation.Besides,the EWS2 slot is close to the blade trailing edge,resulting in massive low-energy fluid accumulating and separating before the slot outlet at positive incidence angles.In contrast,the COM scheme emerges as the most effective solution for comprehensive corner separation control.It can significantly reduce the total pressure loss and improve the static pressure coefficient for the ORI blade at 0°-4° incidence angles,while causing minimal negative impact on the aerodynamic performance at negative incidence angles.Therefore,the corner stall is delayed,and the available incidence angle range is broadened from -10°--2°to -10°-4°.This holds substantial promise for advancing the aerodynamic performance,operational stability,and load capacity of future highly loaded compressors.展开更多
Biological activities of marine benthos such as burrowing and feeding may change sediment characteristics.We conducted three experiments to examine the potential of using juveniles of a spoon worm Urechis unicinctus t...Biological activities of marine benthos such as burrowing and feeding may change sediment characteristics.We conducted three experiments to examine the potential of using juveniles of a spoon worm Urechis unicinctus to improve the quality of organically contaminated coastal sediment.Sediment samples were collected from a site that was heavily contaminated with organic matter (Seonso) and two sites that were clean (Myo-do,Dolsan-do).Urechis juveniles,obtained by artificial fertilization and cultured in the laboratory,were introduced to the sediment (weight 3 kg,depth 10 cm) at a density of 500 individuals per aquarium (length 50 cm,width 35 cm,height 30 cm) (Experiment 1),or at densities ranging from 100 to 900 individuals per beaker (Experiment 2).To examine how sediment contamination can be modified by the effects of Urechis,500 individuals (per aquarium) were exposed to the Seonso contaminated sediment that had been mixed with 0-100% clean sand (Experiment 3).Each experiment lasted two months and sediment samples were collected every 15 d to determine the several indexes of sediment quality,which included acid volatile sulfide (AVS),chemical oxygen demand (COD) and total ignition loss (TIL).In Experiment 1,the existence of Urechis did not result in significant changes in quality indexes in the sediments collected from Myo-do,Dolsan-do.However,AVS,COD and TIL of the Seonso sediment all decreased significantly after co-incubation with Urechis juveniles for 30 to 45 d.Experiment 2 showed that a density of at least 300 juveniles per beaker was necessary to significantly reduce all three quality indexes,and the magnitude of reduction was positively correlated with juvenile density.Experiment 3 revealed that Urechis juveniles were effective in reducing the AVS,COD and TIL of the Seonso sediment that had been mixed with 60%,80%,and 80% of clean sand,respectively.The results of the present study therefore indicated that juveniles of this spoon worm have the potential to be used to improve the quality of organically con展开更多
文摘Background Tourniquets used during total knee arthroplasty may lead to many complications. The aim of this study was to determine perioperative blood loss and its clinical relevance in total knee replacement surgery after applying a tourniquet.Methods From June 2009 to October 2009, 60 consecutive patients who underwent routine total knee arthroplasty were randomly divided into two groups and were treated with or without a tourniquet （30 patients/group）. There were no significant differences in patient baseline characteristics between the two groups. We compared the two groups of patients in terms of intra- and postoperative bleeding, invisible or visible bleeding, and total blood loss.Results None of the patients showed poor wound healing, lower extremity deep venous thrombosis or other complications. The amount of blood loss during surgery was lower in the tourniquet group than in the control group （P〈0.01）. However, postoperative visible bleeding （P 〈0.05） and occult bleeding （P 〈0.05） were significantly greater in the toumiquet group than in the control group. There was no significant difference in the total amount of blood loss between the two groups （P 〉0.05）.Conclusions Tourniquet can reduce bleeding during total knee replacement surgery, but is associated with greater visible and invisible blood loss.
基金supported by the National Nature Science Foundation in China(No.81871740).
文摘Background:Aspirin has demonstrated safety and efficacy for venous thromboembolism(VTE)prophylaxis following total hip arthroplasty(THA);however,inconsistent dose regimens have been reported in the literature.This study aimed to evaluate and compare the safety and efficacy of 100 mg aspirin twice daily with rivaroxaban in VTE prophylaxis following THA.Methods:Patients undergoing elective unilateral primary THA between January 2019 and January 2020 were prospectively enrolled in the study and randomly allocated to receive 5 weeks of VTE prophylaxis with either oral enteric-coated aspirin(100 mg twice daily)or rivaroxaban(10 mg once daily).Medication safety and efficacy were comprehensively evaluated through symptomatic VTE incidence,deep vein thrombosis(DVT)on Doppler ultrasonography,total blood loss(TBL),laboratory bloodwork,Harris hip score(HHS),post-operative recovery,and the incidence of other complications.Results:We included 70 patients in this study;34 and 36 were allocated to receive aspirin and rivaroxaban prophylaxis,respectively.No cases of symptomatic VTE occurred in this study.The DVT rate on Doppler ultrasonography in the aspirin group was not significantly different from that in the rivaroxaban group(8.8%vs.8.3%,χ^(2)=0.01,P=0.91),confirming the non-inferiority of aspirin for DVT prophylaxis(χ^(2)=2.29,P=0.01).The calculated TBL in the aspirin group(944.9 mL[658.5-1137.8 mL])was similar to that in the rivaroxaban group(978.3 mL[747.4-1740.6mL])(χ^(2)=1.55,P=0.12).However,there were no significant inter-group differences in HHS at post-operative day(POD)30(Aspirin:81.0[78.8-83.0],Rivaroxaban:81.0[79.3-83.0],χ^(2)=0.43,P=0.67)and POD 90(Aspirin:90.0[89.0-92.0],Rivaroxaban:91.5[88.3-92.8],χ^(2)=0.77,P=0.44),the incidence of bleeding events(2.9%vs.8.3%,χ^(2)=0.96,P=0.33),or gastrointestinal complications(2.9%vs.5.6%,χ^(2)=1.13,P=0.29).Conclusion:In terms of safety and efficacy,the prophylactic use of 100 mg aspirin twice daily was not statistically different from that of rivaroxaban in preventing
文摘This paper discusses the influence of various volute designs on volute overall performance for a certain centrifu- gal compressor with both vaned and vaneless diffuser. Firstly, based on a free vortex flow pattern and the assumption of a circumferentially uniform flow at the design condition, a corrected method for volute design is adopted. By means of this method, corresponding to five geometric parameters affecting the volute overall performance, ten volute cases are designed. Secondly, the numerical simulation is employed and the detailed flow field and losses in different volutes with different geometric parameters are analyzed. The numerical investigation reveals that in all of the five geometric parameters, the radial location of the cross-section has the strongest influence on the performance of the volute. The non-uniform volute inlet formed by the upward vaned diffuser outlet flow is another important factor. Finally a relatively better value of D1/D2 is concluded.
基金sponsored by the National Natural Science Foundation of China(No.52106057)the National Major Science and Technology Projects of China(No.2017-Ⅱ-0001-0013)+2 种基金Fundamental Research Funds for the Central Universities of China(No.D5000210483)the Foundation of State Level Key Laboratory of Airfoil and Cascade Aerodynamics of China(Nos.D5150210006 and D5050210015)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University of China(No.CX2023012).
文摘To overcome the limitations posed by three-dimensional corner separation,this paper proposes a novel flow control technology known as passive End-Wall(EW)self-adaptive jet.Two single EW slotted schemes(EWS1 and EWS2),alongside a combined(COM)scheme featuring double EW slots,were investigated.The results reveal that the EW slot,driven by pressure differentials between the pressure and suction sides,can generate an adaptive jet with escalating velocity as the operational load increases.This high-speed jet effectively re-excites the local low-energy fluid,thereby mitigating the corner separation.Notably,the EWS1 slot,positioned near the blade leading edge,exhibits relatively low jet velocities at negative incidence angles,causing jet separation and exacerbating the corner separation.Besides,the EWS2 slot is close to the blade trailing edge,resulting in massive low-energy fluid accumulating and separating before the slot outlet at positive incidence angles.In contrast,the COM scheme emerges as the most effective solution for comprehensive corner separation control.It can significantly reduce the total pressure loss and improve the static pressure coefficient for the ORI blade at 0°-4° incidence angles,while causing minimal negative impact on the aerodynamic performance at negative incidence angles.Therefore,the corner stall is delayed,and the available incidence angle range is broadened from -10°--2°to -10°-4°.This holds substantial promise for advancing the aerodynamic performance,operational stability,and load capacity of future highly loaded compressors.
文摘Biological activities of marine benthos such as burrowing and feeding may change sediment characteristics.We conducted three experiments to examine the potential of using juveniles of a spoon worm Urechis unicinctus to improve the quality of organically contaminated coastal sediment.Sediment samples were collected from a site that was heavily contaminated with organic matter (Seonso) and two sites that were clean (Myo-do,Dolsan-do).Urechis juveniles,obtained by artificial fertilization and cultured in the laboratory,were introduced to the sediment (weight 3 kg,depth 10 cm) at a density of 500 individuals per aquarium (length 50 cm,width 35 cm,height 30 cm) (Experiment 1),or at densities ranging from 100 to 900 individuals per beaker (Experiment 2).To examine how sediment contamination can be modified by the effects of Urechis,500 individuals (per aquarium) were exposed to the Seonso contaminated sediment that had been mixed with 0-100% clean sand (Experiment 3).Each experiment lasted two months and sediment samples were collected every 15 d to determine the several indexes of sediment quality,which included acid volatile sulfide (AVS),chemical oxygen demand (COD) and total ignition loss (TIL).In Experiment 1,the existence of Urechis did not result in significant changes in quality indexes in the sediments collected from Myo-do,Dolsan-do.However,AVS,COD and TIL of the Seonso sediment all decreased significantly after co-incubation with Urechis juveniles for 30 to 45 d.Experiment 2 showed that a density of at least 300 juveniles per beaker was necessary to significantly reduce all three quality indexes,and the magnitude of reduction was positively correlated with juvenile density.Experiment 3 revealed that Urechis juveniles were effective in reducing the AVS,COD and TIL of the Seonso sediment that had been mixed with 60%,80%,and 80% of clean sand,respectively.The results of the present study therefore indicated that juveniles of this spoon worm have the potential to be used to improve the quality of organically con
