AIM: To analyze the risk factors for central port failure in cancer patients administered chemotherapy, using univariate and multivariate analyses. METHODS: A total of 1348 totally implantable venous access devices (T...AIM: To analyze the risk factors for central port failure in cancer patients administered chemotherapy, using univariate and multivariate analyses. METHODS: A total of 1348 totally implantable venous access devices (TIVADs) were implanted into 1280 cancer patients in this cohort study. A Cox proportional hazard model was applied to analyze risk factors for failure of TIVADs. Log-rank test was used to compare actuarial survival rates. Infection, thrombosis, and surgical complication rates (χ2 test or Fisher's exact test) were compared in relation to the risk factors. RESULTS: Increasing age, male gender and openended catheter use were signifi cant risk factors reducing survival of TIVADs as determined by univariate and multivariate analyses. Hematogenous malignancy decreased the survival time of TIVADs; this reduction was not statistically signifi cant by univariate analysis [hazard ratio (HR) = 1.336, 95% CI: 0.966-1.849, P = 0.080)]. However, it became a signifi cant risk factor by multivariate analysis (HR = 1.499, 95% CI: 1.079-2.083, P = 0.016) when correlated with variables of age, sex and catheter type. Close-ended (Groshong) catheters had a lower thrombosis rate than open-ended catheters (2.5% vs 5%, P = 0.015). Hematogenous malignancy had higher infection rates than solid malignancy (10.5% vs 2.5%, P < 0.001). CONCLUSION: Increasing age, male gender, openended catheters and hematogenous malignancy were risk factors for TIVAD failure. Close-ended catheters had lower thrombosis rates and hematogenous malignancy had higher infection rates.展开更多
Associating liver partition and portal vein ligation for staged hepatectomy(ALPPS) has been recently demonstrated as a method to induce rapid and extensive hypertrophy within a short time and has been employed for a v...Associating liver partition and portal vein ligation for staged hepatectomy(ALPPS) has been recently demonstrated as a method to induce rapid and extensive hypertrophy within a short time and has been employed for a variety of primary and metastatic liver tumors. However, controversies remain due to its high morbidity and mortality. To enable safer surgery, liver surgeons have searched for better technical modifications, such as partial ALPPS, mini-ALPPS, minimally invasive ALPPS, and Terminal branches portal vein Embolization Liver Partition for Planned hepatectomy(TELPP). It seems that TELPP is very promising, because it has the main advantage of ALPPS-the rapid increase of future liver remnant volume, but the morbidity and mortality are much lower because only one surgical operation is required.展开更多
A mechanical model of the quasi-static interface of a mode I crack between a rigid and a pressure-sensitive viscoelastic material was established to investigate the mechanical characteristic of ship-building engineeri...A mechanical model of the quasi-static interface of a mode I crack between a rigid and a pressure-sensitive viscoelastic material was established to investigate the mechanical characteristic of ship-building engineering hi-materials. In the stable growth stage, stress and strain have the same singularity, ie （σ, ε） ∝ r^-1/（n-1）. The variable-separable asymptotic solutions of stress and strain at the crack tip were obtained by adopting Airy＇s stress function and the numerical results of stress and strain in the crack-tip field were obtained by the shooting method. The results showed that the near-tip fields are mainly governed by the power-hardening exponent n and the Poisson ratio v of the pressure-sensitive material. The fracture criterion of mode I quasi-static crack growth in pressure-sensitive materials, according to the asymptotic analyses of the crack-tip field, can be viewed from the perspective of strain.展开更多
This paper deals with an innovative low-loss AC switch, named as TBBS （transistor based bidirectional switch）, based on the association of super-gain BJTs developed by the GREMAN laboratory. The main characterizatio...This paper deals with an innovative low-loss AC switch, named as TBBS （transistor based bidirectional switch）, based on the association of super-gain BJTs developed by the GREMAN laboratory. The main characterization results of the super-gain BJT are reminded to identify the key parameters that are essential to build the TBBS. A complete characterization database in static mode of this new AC switch is discussed. In particular, its forward and reverse-biased features have been measured to see the evolution of the DC current gain as a function of the current density. The TBBS makes sense when using the super-gain BJT （bipolar junction transistor） in reverse mode. It means that the reverse DC current gain has to be sufficient （at least higher than l compared with the conventional BJT one）. This new AC switch is bidirectional in current and voltage, totally controllable （turn-on and turn-off） and the most attractive solution in terms of on-state power losses. Further, its manufacturing process is as easier as existing device such as triac.展开更多
To reveal the water inrush mechanics of underground deep rock mass subjected to dynamic disturbance such as blasting, compression-shear rock crack initiation rule and the evolution of crack tip stress intensity factor...To reveal the water inrush mechanics of underground deep rock mass subjected to dynamic disturbance such as blasting, compression-shear rock crack initiation rule and the evolution of crack tip stress intensity factor are analyzed under static-dynamic loading and seepage water pressure on the basis of theoretical deduction and experimental research. It is shown that the major influence factors of the crack tip stress intensity factor are seepage pressure, dynamic load, static stress and crack angle. The existence of seepage water pressure aggravates propagation of branch cracks. With the seepage pressure increasing, the branch crack experiences unstable extension from stable propagation. The dynamic load in the direction of maximum main stress increases type I crack tip stress intensity factor and its influence on type II crack intensity factor is related with crack angle and material property. Crack initiation angle changes with the dynamic load. The initial crack initiation angle of type I dynamic crack fracture is 70.5°. The compression-shear crack initial strength is related to seepage pressure, confining pressure, and dynamic load. Experimental results verify that the initial crack strength increases with the confining pressure increasing, and decreases with the seepage pressure increasing.展开更多
The effect of electrostatic tractions on the fracture behavior of a dielectric material under mechanical and/or electric loading is analyzed,by studying a pre-cracked parallel-plate capacitor,and illustrated by plots....The effect of electrostatic tractions on the fracture behavior of a dielectric material under mechanical and/or electric loading is analyzed,by studying a pre-cracked parallel-plate capacitor,and illustrated by plots.The results indicate that electrostatic tractions on the electrodes compress the material in front of the crack tip,while electrostatic tractions on the crack faces have the tendency to close the crack and stretch the material behind the crack tip.Mechanical load is the driving force to propagate the crack,while applied electric field retards crack propagation due to the electrostatic tractions.As a direct consequence,the fracture criterion is composed of two parts:the energy release rate must exceed a critical value and the mechanical load must be higher than the critical value for crack opening.展开更多
文摘AIM: To analyze the risk factors for central port failure in cancer patients administered chemotherapy, using univariate and multivariate analyses. METHODS: A total of 1348 totally implantable venous access devices (TIVADs) were implanted into 1280 cancer patients in this cohort study. A Cox proportional hazard model was applied to analyze risk factors for failure of TIVADs. Log-rank test was used to compare actuarial survival rates. Infection, thrombosis, and surgical complication rates (χ2 test or Fisher's exact test) were compared in relation to the risk factors. RESULTS: Increasing age, male gender and openended catheter use were signifi cant risk factors reducing survival of TIVADs as determined by univariate and multivariate analyses. Hematogenous malignancy decreased the survival time of TIVADs; this reduction was not statistically signifi cant by univariate analysis [hazard ratio (HR) = 1.336, 95% CI: 0.966-1.849, P = 0.080)]. However, it became a signifi cant risk factor by multivariate analysis (HR = 1.499, 95% CI: 1.079-2.083, P = 0.016) when correlated with variables of age, sex and catheter type. Close-ended (Groshong) catheters had a lower thrombosis rate than open-ended catheters (2.5% vs 5%, P = 0.015). Hematogenous malignancy had higher infection rates than solid malignancy (10.5% vs 2.5%, P < 0.001). CONCLUSION: Increasing age, male gender, openended catheters and hematogenous malignancy were risk factors for TIVAD failure. Close-ended catheters had lower thrombosis rates and hematogenous malignancy had higher infection rates.
基金Supported by the National Natural Science Foundation of China,No.81570559 and No.81272673
文摘Associating liver partition and portal vein ligation for staged hepatectomy(ALPPS) has been recently demonstrated as a method to induce rapid and extensive hypertrophy within a short time and has been employed for a variety of primary and metastatic liver tumors. However, controversies remain due to its high morbidity and mortality. To enable safer surgery, liver surgeons have searched for better technical modifications, such as partial ALPPS, mini-ALPPS, minimally invasive ALPPS, and Terminal branches portal vein Embolization Liver Partition for Planned hepatectomy(TELPP). It seems that TELPP is very promising, because it has the main advantage of ALPPS-the rapid increase of future liver remnant volume, but the morbidity and mortality are much lower because only one surgical operation is required.
基金Supported by Heilongjiang Province Foundation under Grant No.LC08C02
文摘A mechanical model of the quasi-static interface of a mode I crack between a rigid and a pressure-sensitive viscoelastic material was established to investigate the mechanical characteristic of ship-building engineering hi-materials. In the stable growth stage, stress and strain have the same singularity, ie （σ, ε） ∝ r^-1/（n-1）. The variable-separable asymptotic solutions of stress and strain at the crack tip were obtained by adopting Airy＇s stress function and the numerical results of stress and strain in the crack-tip field were obtained by the shooting method. The results showed that the near-tip fields are mainly governed by the power-hardening exponent n and the Poisson ratio v of the pressure-sensitive material. The fracture criterion of mode I quasi-static crack growth in pressure-sensitive materials, according to the asymptotic analyses of the crack-tip field, can be viewed from the perspective of strain.
文摘This paper deals with an innovative low-loss AC switch, named as TBBS （transistor based bidirectional switch）, based on the association of super-gain BJTs developed by the GREMAN laboratory. The main characterization results of the super-gain BJT are reminded to identify the key parameters that are essential to build the TBBS. A complete characterization database in static mode of this new AC switch is discussed. In particular, its forward and reverse-biased features have been measured to see the evolution of the DC current gain as a function of the current density. The TBBS makes sense when using the super-gain BJT （bipolar junction transistor） in reverse mode. It means that the reverse DC current gain has to be sufficient （at least higher than l compared with the conventional BJT one）. This new AC switch is bidirectional in current and voltage, totally controllable （turn-on and turn-off） and the most attractive solution in terms of on-state power losses. Further, its manufacturing process is as easier as existing device such as triac.
基金Projects(51174228,51174088,51204068,51274097)supported by the National Natural Science Foundation of China
文摘To reveal the water inrush mechanics of underground deep rock mass subjected to dynamic disturbance such as blasting, compression-shear rock crack initiation rule and the evolution of crack tip stress intensity factor are analyzed under static-dynamic loading and seepage water pressure on the basis of theoretical deduction and experimental research. It is shown that the major influence factors of the crack tip stress intensity factor are seepage pressure, dynamic load, static stress and crack angle. The existence of seepage water pressure aggravates propagation of branch cracks. With the seepage pressure increasing, the branch crack experiences unstable extension from stable propagation. The dynamic load in the direction of maximum main stress increases type I crack tip stress intensity factor and its influence on type II crack intensity factor is related with crack angle and material property. Crack initiation angle changes with the dynamic load. The initial crack initiation angle of type I dynamic crack fracture is 70.5°. The compression-shear crack initial strength is related to seepage pressure, confining pressure, and dynamic load. Experimental results verify that the initial crack strength increases with the confining pressure increasing, and decreases with the seepage pressure increasing.
基金supported by the Hong Kong Research Grants Council(Grant No. 622610)supported by the Nanotechnology Program at HKUST
文摘The effect of electrostatic tractions on the fracture behavior of a dielectric material under mechanical and/or electric loading is analyzed,by studying a pre-cracked parallel-plate capacitor,and illustrated by plots.The results indicate that electrostatic tractions on the electrodes compress the material in front of the crack tip,while electrostatic tractions on the crack faces have the tendency to close the crack and stretch the material behind the crack tip.Mechanical load is the driving force to propagate the crack,while applied electric field retards crack propagation due to the electrostatic tractions.As a direct consequence,the fracture criterion is composed of two parts:the energy release rate must exceed a critical value and the mechanical load must be higher than the critical value for crack opening.
