The aim of this study was to examine whether vitamin C reduced mortality when adjutant therapy of patients with septic shock and severe sepsis compared with placebo by meta-analysis. Eligible trials were identified fr...The aim of this study was to examine whether vitamin C reduced mortality when adjutant therapy of patients with septic shock and severe sepsis compared with placebo by meta-analysis. Eligible trials were identified from Pubmed, Embase, Ovid, and the Cochrane database. Four randomized controlled trials (RCT) and two retrospective studies were published between 2000 and 2017 met the inclusion criteria and suitable for meta-analysis. The data were analyzed with randomized-effects or fixed-effects models using Review Manager Version 5.3. Four randomized studies with a total of 109 participants were suitable for meta-analysis. The heterogeneity was assessed by calculating the Q and I2 methods. A random-effects approach instead of a fixed-effects analysis was undertaken if I2 > 50%. Adjuvant vitamin C did not associate with a reduction in mortality as compared with placebo, it is occurred similarly in both RCT studies and retrospective studies. However, high doses of vitamin C (>50 mg/kg/day) significant reduced the mortality rate of severe sepsis patients. And administration of high doses of vitamin C to therapy severe sepsis did not significantly reduce the ICU length of stay. The results suggested a trend toward reducing mortality in severe sepsis and septic shock patients’ adjuvant with vitamin C. Further multicenter large randomized controlled trials are necessary to determine the potential benefits of vitamin C in patients with severe sepsis and septic shock.展开更多
The critical angle is the angle at which the contrast of oil slicks reverse their contrasts against the surrounding oil-free seawater under sunglint.Accurate determination of the critical angle can help estimate surfa...The critical angle is the angle at which the contrast of oil slicks reverse their contrasts against the surrounding oil-free seawater under sunglint.Accurate determination of the critical angle can help estimate surface roughness and refractive index of the oil slicks.Although it’s difficult to determine a certain critical angle,the potential critical angle range help to improve the estimation accuracy.In this study,the angle between the viewing direction and the direction of mirror reflection is used as an indicator for quantifying the critical angle and could be calculated from the solar/viewing geometry from observations of the Moderate Resolution Imaging Spectroradiometer(MODIS).The natural seep oil slicks in the Gulf of Mexico were first delineated using a customized segmentation approach to remove noise and apply a morphological filter.On the basis of the histograms of the brightness values of the delineated oil slicks,the potential range of the critical angle was determined,and then an optimal critical angle between oil slicks and seawater was then determined from statistical and regression analyses in this range.This critical angle corresponds to the best fitting between the modeled and observed surface roughness of seep oil slicks and seawater.展开更多
文摘The aim of this study was to examine whether vitamin C reduced mortality when adjutant therapy of patients with septic shock and severe sepsis compared with placebo by meta-analysis. Eligible trials were identified from Pubmed, Embase, Ovid, and the Cochrane database. Four randomized controlled trials (RCT) and two retrospective studies were published between 2000 and 2017 met the inclusion criteria and suitable for meta-analysis. The data were analyzed with randomized-effects or fixed-effects models using Review Manager Version 5.3. Four randomized studies with a total of 109 participants were suitable for meta-analysis. The heterogeneity was assessed by calculating the Q and I2 methods. A random-effects approach instead of a fixed-effects analysis was undertaken if I2 > 50%. Adjuvant vitamin C did not associate with a reduction in mortality as compared with placebo, it is occurred similarly in both RCT studies and retrospective studies. However, high doses of vitamin C (>50 mg/kg/day) significant reduced the mortality rate of severe sepsis patients. And administration of high doses of vitamin C to therapy severe sepsis did not significantly reduce the ICU length of stay. The results suggested a trend toward reducing mortality in severe sepsis and septic shock patients’ adjuvant with vitamin C. Further multicenter large randomized controlled trials are necessary to determine the potential benefits of vitamin C in patients with severe sepsis and septic shock.
基金Natural Science Foundation of Jiangsu Province[Grant no.BK20160023] National Natural Science Foundation of China[Grant Nos.41771376,41371014,61675099]the National Key Research and Development Program of China[Grant no.2016YFC1400901].
文摘The critical angle is the angle at which the contrast of oil slicks reverse their contrasts against the surrounding oil-free seawater under sunglint.Accurate determination of the critical angle can help estimate surface roughness and refractive index of the oil slicks.Although it’s difficult to determine a certain critical angle,the potential critical angle range help to improve the estimation accuracy.In this study,the angle between the viewing direction and the direction of mirror reflection is used as an indicator for quantifying the critical angle and could be calculated from the solar/viewing geometry from observations of the Moderate Resolution Imaging Spectroradiometer(MODIS).The natural seep oil slicks in the Gulf of Mexico were first delineated using a customized segmentation approach to remove noise and apply a morphological filter.On the basis of the histograms of the brightness values of the delineated oil slicks,the potential range of the critical angle was determined,and then an optimal critical angle between oil slicks and seawater was then determined from statistical and regression analyses in this range.This critical angle corresponds to the best fitting between the modeled and observed surface roughness of seep oil slicks and seawater.
