Arc plasma jet flow in the air was investigated under a bridge-type contacts in a DC 270 V resistive circuit. We characterized the arc plasma jet flow appearance at different currents by using high-speed photography, ...Arc plasma jet flow in the air was investigated under a bridge-type contacts in a DC 270 V resistive circuit. We characterized the arc plasma jet flow appearance at different currents by using high-speed photography, and two polished contacts were used to search for the relationship between roughness and plasma jet flow. Then, to make the nature of arc plasma jet flow phenomena clear, a simplified model based on magnetohydrodynamic （MHD） theory was established and calculated. The simulated DC arc plasma was presented with the temperature distribution and the current density distribution. Furthermore, the calculated arc flow velocity field showed that the circular vortex was an embodiment of the arc plasma jet flow progress. The combined action of volume force and contact surface was the main reason of the arc jet flow.展开更多
BK virus (BKV) may cause nephropathy in renal transplant recipients receiving immunosuppressive therapy, resulting in renal dysfunction and, possibly graft loss. However, the positive and negative predictive values of...BK virus (BKV) may cause nephropathy in renal transplant recipients receiving immunosuppressive therapy, resulting in renal dysfunction and, possibly graft loss. However, the positive and negative predictive values of BK viral load are still controversial. In this prospective, single-center study, BKV DNA was measured 1, 3 and 6 months after transplantation. The viral load in urine and plasma was quantified with the real-time Q-PCR (Argen kit) in 73 renal allograft recipients Three of them showed acute rejection. To determine the cutoff value of viral load, 60 sera samples of healthy blood donors, matched for age and sex, were tested. The mean plasmatic viral load one month post-transplantation was statistically higher in renal transplant recipients (17.23 copies/ml) compared to that in controls (2 copies/ml) (p: 0.06). This difference of the distribution of viremia values is more evident in the third and sixth month (p: 0.002 and 0.010 respectively). Furthermore, analysis of the kinetic of viral load revealed an average rise of viremia at 3 months (1589.14 copies/ml) followed by its decrease at 6 months (249.75 copies/ml). However, the difference was not statistically significant. The same is true for the distribution of values of viruria and in all cases the average viral load was statistically higher in urine than in plasma. In addition, this study did not shown significant relationsheep between viremia/viruria and the occurrence of acute rejection, the renal function deterioration, the source of allograft or immunosuppressive therapy protocol. If the results of this study demonstrate the importance of the replication of BKV in renal transplant patients from the first month compared to that in immunocompetent subjects, the screening of the DNA of this virus does not appear to have a prognostic value in the occurrence of acute rejection. However, the plasma and urine monitoring of BKV load beyond 6 months , not appear to exclude the relationsheep between these two biomarkers and the occurrence of chronic graft dysfunction.展开更多
Background: The success of antiretroviral therapy requires better virological monitoring. We described the virological profile of patients on combined antiretroviral therapy (cART) for HIV/AIDS in Bangui, Central Afri...Background: The success of antiretroviral therapy requires better virological monitoring. We described the virological profile of patients on combined antiretroviral therapy (cART) for HIV/AIDS in Bangui, Central African Republic (CAR). Methods: In this prospective cohort study of patients who had been on combined antiretroviral therapy treatment (cART) for at least 12 months in Bangui, only one HIV plasma viral load per patient was realized at the Institut Pasteur of Bangui, between April 4th and November 28th, 2017. Sociodemographic and biological data were collected. Blood samples were taken for viral load. The biocentric generic human immunodeficiency virus (HIV) load test was used to quantify a ribonucleic acid (RNA) HIV-1. Data were analyzed with Stata software version 14. Chi-squared test was used to analyse viral load according to sex and age. The level of significance was set at P ≤ 0.05. Results: A total of 3569 patients were recruited, with a mean age of 40 years (median, 42 years;range, 1 - 84), patients aged 40 - 49 predominating (34.2%). The sex ratio was 0.4. No virus was detectable in plasma from 49.2% of patients, while 42.4% had virological failure (viral load, ≥1000 copies/mL) according to WHO criteria. The risk for virological failure decreased with age (P = 0.001) and was higher among females than males (P = 0.001). Conclusions: The rate of virological failure among patients on cART is very high in the CAR, despite the availability of and access to monitoring of HIV plasma viral load in Bangui. Therefore, adherence to treatment should be evaluated and reinforced in Bangui, CAR.展开更多
基金supported by National Natural Science Foundation of China(Nos.51307030,51277038)
文摘Arc plasma jet flow in the air was investigated under a bridge-type contacts in a DC 270 V resistive circuit. We characterized the arc plasma jet flow appearance at different currents by using high-speed photography, and two polished contacts were used to search for the relationship between roughness and plasma jet flow. Then, to make the nature of arc plasma jet flow phenomena clear, a simplified model based on magnetohydrodynamic （MHD） theory was established and calculated. The simulated DC arc plasma was presented with the temperature distribution and the current density distribution. Furthermore, the calculated arc flow velocity field showed that the circular vortex was an embodiment of the arc plasma jet flow progress. The combined action of volume force and contact surface was the main reason of the arc jet flow.
文摘BK virus (BKV) may cause nephropathy in renal transplant recipients receiving immunosuppressive therapy, resulting in renal dysfunction and, possibly graft loss. However, the positive and negative predictive values of BK viral load are still controversial. In this prospective, single-center study, BKV DNA was measured 1, 3 and 6 months after transplantation. The viral load in urine and plasma was quantified with the real-time Q-PCR (Argen kit) in 73 renal allograft recipients Three of them showed acute rejection. To determine the cutoff value of viral load, 60 sera samples of healthy blood donors, matched for age and sex, were tested. The mean plasmatic viral load one month post-transplantation was statistically higher in renal transplant recipients (17.23 copies/ml) compared to that in controls (2 copies/ml) (p: 0.06). This difference of the distribution of viremia values is more evident in the third and sixth month (p: 0.002 and 0.010 respectively). Furthermore, analysis of the kinetic of viral load revealed an average rise of viremia at 3 months (1589.14 copies/ml) followed by its decrease at 6 months (249.75 copies/ml). However, the difference was not statistically significant. The same is true for the distribution of values of viruria and in all cases the average viral load was statistically higher in urine than in plasma. In addition, this study did not shown significant relationsheep between viremia/viruria and the occurrence of acute rejection, the renal function deterioration, the source of allograft or immunosuppressive therapy protocol. If the results of this study demonstrate the importance of the replication of BKV in renal transplant patients from the first month compared to that in immunocompetent subjects, the screening of the DNA of this virus does not appear to have a prognostic value in the occurrence of acute rejection. However, the plasma and urine monitoring of BKV load beyond 6 months , not appear to exclude the relationsheep between these two biomarkers and the occurrence of chronic graft dysfunction.
文摘Background: The success of antiretroviral therapy requires better virological monitoring. We described the virological profile of patients on combined antiretroviral therapy (cART) for HIV/AIDS in Bangui, Central African Republic (CAR). Methods: In this prospective cohort study of patients who had been on combined antiretroviral therapy treatment (cART) for at least 12 months in Bangui, only one HIV plasma viral load per patient was realized at the Institut Pasteur of Bangui, between April 4th and November 28th, 2017. Sociodemographic and biological data were collected. Blood samples were taken for viral load. The biocentric generic human immunodeficiency virus (HIV) load test was used to quantify a ribonucleic acid (RNA) HIV-1. Data were analyzed with Stata software version 14. Chi-squared test was used to analyse viral load according to sex and age. The level of significance was set at P ≤ 0.05. Results: A total of 3569 patients were recruited, with a mean age of 40 years (median, 42 years;range, 1 - 84), patients aged 40 - 49 predominating (34.2%). The sex ratio was 0.4. No virus was detectable in plasma from 49.2% of patients, while 42.4% had virological failure (viral load, ≥1000 copies/mL) according to WHO criteria. The risk for virological failure decreased with age (P = 0.001) and was higher among females than males (P = 0.001). Conclusions: The rate of virological failure among patients on cART is very high in the CAR, despite the availability of and access to monitoring of HIV plasma viral load in Bangui. Therefore, adherence to treatment should be evaluated and reinforced in Bangui, CAR.
