BACKGROUND Radiologic adjacent segment degeneration(ASDeg)can occur after spinal surgery.Adjacent segment disease(ASDis)is defined as the development of new clinical symptoms corresponding to radiographic changes adja...BACKGROUND Radiologic adjacent segment degeneration(ASDeg)can occur after spinal surgery.Adjacent segment disease(ASDis)is defined as the development of new clinical symptoms corresponding to radiographic changes adjacent to the level of previous spinal surgery.Greater pre-existing ASDeg is generally considered to result in more severe ASDis;nonetheless,whether the ASDeg status before index surgery influences the postoperative risk of revision surgery due to ASDis warrants investigation.AIM To identify possible risk factors for ASDis and verify the concept that greater preexisting ASDeg leads to more severe ASDis.METHODS Data from 212 patients who underwent posterior decompression with Dynesys stabilization from January 2006 to June 2016 were retrospectively analyzed.Patients who underwent surgery for ASDis were categorized as group A(n=13),whereas those who did not were classified as group B(n=199).Survival analysis and Cox proportional hazards models were used to compare the modified Pfirrmann grade,University of California-Los Angeles grade,body mass index,number of Dynesys-instrumented levels,and age.RESULTS The mean time of reoperation was 7.22(1.65–11.84)years in group A,and the mean follow-up period was 6.09(0.10–12.76)years in group B.No significant difference in reoperation risk was observed:Modified Pfirrmann grade 3 vs 4(P=0.53)or 4 vs 5(P=0.46)for the upper adjacent disc,University of California-Los Angeles grade 2 vs 3 for the upper adjacent segment(P=0.66),age of<60 vs>60 years(P=0.9),body mass index<25 vs>25 kg/m2(P=0.3),and sex(P=0.8).CONCLUSION Greater preexisting upper ASDeg was not associated with a higher rate of reoperation for ASDis after Dynesys surgery.Being overweight tended to increase reoperation risk after Dynesys surgery for ASDis.展开更多
This research aims to simulate a gravity flow fractionation—the process to fractionate erythrocytes through gravitational field using ANSYS simulation software. A particular microfluidic channel was designed as a sep...This research aims to simulate a gravity flow fractionation—the process to fractionate erythrocytes through gravitational field using ANSYS simulation software. A particular microfluidic channel was designed as a separation device. The gravitational equilibrium conditions of the erythrocytes and gravitational field as the parameters were chosen, then deriving the erythrocytes’ path through numerical simulations. After the actual analog measurements, there is no big difference between the flow velocity and the pressure under +/–10% atmosphere condition. According to the simulation results, the particle with the size 8 μm (similar to the erythrocyte size) can be separated to the outside channel and discharged from the collecting area, other particles with the size 9 μm will stay in the fluid motion and can be collected in the final collection area for preservation. Through the analog analysis by using the software-ANSYS-Fluent, the complete flowing path of the particles and the feasibility of the Gravity-Flow Fractionation can be directly proven.展开更多
A configuration consisting of a double slit and pipe in conjunction with moving fluid is proposed to manipulate a broadband light source through the interference spectrum. Theoretical analysis shows that, by varying t...A configuration consisting of a double slit and pipe in conjunction with moving fluid is proposed to manipulate a broadband light source through the interference spectrum. Theoretical analysis shows that, by varying the speed of the fluid, the scheme can act as a special dynamic frequency filter and produce regular dark lines that may serve as an optical frequency ruler.展开更多
基金The study was approved by our institutional review board,Research Ethics Committee China Medical University and Hospital,Taichung,Taiwan(Protocol No.:CMUH108-REC2-133).
文摘BACKGROUND Radiologic adjacent segment degeneration(ASDeg)can occur after spinal surgery.Adjacent segment disease(ASDis)is defined as the development of new clinical symptoms corresponding to radiographic changes adjacent to the level of previous spinal surgery.Greater pre-existing ASDeg is generally considered to result in more severe ASDis;nonetheless,whether the ASDeg status before index surgery influences the postoperative risk of revision surgery due to ASDis warrants investigation.AIM To identify possible risk factors for ASDis and verify the concept that greater preexisting ASDeg leads to more severe ASDis.METHODS Data from 212 patients who underwent posterior decompression with Dynesys stabilization from January 2006 to June 2016 were retrospectively analyzed.Patients who underwent surgery for ASDis were categorized as group A(n=13),whereas those who did not were classified as group B(n=199).Survival analysis and Cox proportional hazards models were used to compare the modified Pfirrmann grade,University of California-Los Angeles grade,body mass index,number of Dynesys-instrumented levels,and age.RESULTS The mean time of reoperation was 7.22(1.65–11.84)years in group A,and the mean follow-up period was 6.09(0.10–12.76)years in group B.No significant difference in reoperation risk was observed:Modified Pfirrmann grade 3 vs 4(P=0.53)or 4 vs 5(P=0.46)for the upper adjacent disc,University of California-Los Angeles grade 2 vs 3 for the upper adjacent segment(P=0.66),age of<60 vs>60 years(P=0.9),body mass index<25 vs>25 kg/m2(P=0.3),and sex(P=0.8).CONCLUSION Greater preexisting upper ASDeg was not associated with a higher rate of reoperation for ASDis after Dynesys surgery.Being overweight tended to increase reoperation risk after Dynesys surgery for ASDis.
文摘This research aims to simulate a gravity flow fractionation—the process to fractionate erythrocytes through gravitational field using ANSYS simulation software. A particular microfluidic channel was designed as a separation device. The gravitational equilibrium conditions of the erythrocytes and gravitational field as the parameters were chosen, then deriving the erythrocytes’ path through numerical simulations. After the actual analog measurements, there is no big difference between the flow velocity and the pressure under +/–10% atmosphere condition. According to the simulation results, the particle with the size 8 μm (similar to the erythrocyte size) can be separated to the outside channel and discharged from the collecting area, other particles with the size 9 μm will stay in the fluid motion and can be collected in the final collection area for preservation. Through the analog analysis by using the software-ANSYS-Fluent, the complete flowing path of the particles and the feasibility of the Gravity-Flow Fractionation can be directly proven.
基金supported by the National Science Council of Taiwan,China(No.101-2221-E-005-062-MY3)the National Chung Hsing University,China
文摘A configuration consisting of a double slit and pipe in conjunction with moving fluid is proposed to manipulate a broadband light source through the interference spectrum. Theoretical analysis shows that, by varying the speed of the fluid, the scheme can act as a special dynamic frequency filter and produce regular dark lines that may serve as an optical frequency ruler.
