A geoelectrical survey using the electrical resistivity method was carried out in the Mayo Boki (Northern Cameroon), to investigate the subsurface layering and evaluation of the limestone characteristics. In addition ...A geoelectrical survey using the electrical resistivity method was carried out in the Mayo Boki (Northern Cameroon), to investigate the subsurface layering and evaluation of the limestone characteristics. In addition to geological data collection, three vertical electrical soundings and one electrical resistivity profile were measured. Joint interpretation of the DC data allows us to obtain reliable 1D models of the resistivity distribution. The interpretation of the field data was carried out using the RES2DINV software, which converts the apparent resistivity as a function of electrode spacing to the true resistivity as a function of depth in two dimensions. The results obtained from the electrical resistivity survey showed that: 1) A limestone layer was put in evidence at a depth of 4 m and the thickness varies from 13 m to 44 m;2) The limestone layer resistivity is ranged from 125 to 2410 ohm.m;3) An area of probable limestone deposit with interesting thicknesses have been identified. These facts are useful for future mining exploration as drilling map definition and operations. The geologic section of a nearby location termed resistivity profile was delineated and its total depth was found to be 57 m, which corroborates the lithologs of the boreholes from the area. The correlation of geological data and the geoelectric section has led to envisage pursuing exploration activities. Based on the limestone layer characteristics extracted from this DC investigation, the exploration drilling operations have to be initiated in order to define the limestone resource over the area of study, which will certainly enables to built the exploitation project prefeasibility document.展开更多
Background and Aims:Patients with cirrhosis of the liver have high mortality after surgery.We investigated the mortality in patients with cirrhosis of the liver who underwent surgery other than liver transplant and ap...Background and Aims:Patients with cirrhosis of the liver have high mortality after surgery.We investigated the mortality in patients with cirrhosis of the liver who underwent surgery other than liver transplant and applied the Mayo clinic model to predict mortality and compare with the observed mortality.We also studied the association of the observed mortality with the Child-Turcotte-Pugh(CTP)class and the model for end-stage liver disease(MELD)and model for end-stage liver disease-sodium(MELD-Na)scores.Methods:The electronic records database of our hospital was accessed to analyze the data of 133 cirrhotic patients who underwent various surgeries under general anesthesia from October 2009 to June 2017.The Mayo risk score was applied to each and used to calculate predicted mortality;the MELD and MELD-Na scores were also calculated.Telephonic interview was performed with the patients and or their relative to ascertain survival or time of death after surgery,when the information was not available from the hospital records.Results:The all-cause observed mortality rates at postoperative days 30 and 90 and at 1 year were 12%,20.3%and 26.3%respectively.The area under the receiver operating characteristic curve values for the Mayo model as a predictor of 30-day,90-day and 1-year mortality were 0.836,0.828 and 0.744 respectively.Good correlation was seen for observed mortality with CTP class and with MELD and MELD-Na scores.Conclusions:The Mayo model for predicting postoperative mortality in patients with cirrhosis of the liver demonstrated good correlation in this study.The strength of prediction of mortality by Mayo risk score calculation was similar at postoperative days 30 and 90 but decreased at 1-year after the surgery.Good correlation was seen for the observed mortality with MELD,MELD-Na and CTP scores.展开更多
文摘A geoelectrical survey using the electrical resistivity method was carried out in the Mayo Boki (Northern Cameroon), to investigate the subsurface layering and evaluation of the limestone characteristics. In addition to geological data collection, three vertical electrical soundings and one electrical resistivity profile were measured. Joint interpretation of the DC data allows us to obtain reliable 1D models of the resistivity distribution. The interpretation of the field data was carried out using the RES2DINV software, which converts the apparent resistivity as a function of electrode spacing to the true resistivity as a function of depth in two dimensions. The results obtained from the electrical resistivity survey showed that: 1) A limestone layer was put in evidence at a depth of 4 m and the thickness varies from 13 m to 44 m;2) The limestone layer resistivity is ranged from 125 to 2410 ohm.m;3) An area of probable limestone deposit with interesting thicknesses have been identified. These facts are useful for future mining exploration as drilling map definition and operations. The geologic section of a nearby location termed resistivity profile was delineated and its total depth was found to be 57 m, which corroborates the lithologs of the boreholes from the area. The correlation of geological data and the geoelectric section has led to envisage pursuing exploration activities. Based on the limestone layer characteristics extracted from this DC investigation, the exploration drilling operations have to be initiated in order to define the limestone resource over the area of study, which will certainly enables to built the exploitation project prefeasibility document.
文摘Background and Aims:Patients with cirrhosis of the liver have high mortality after surgery.We investigated the mortality in patients with cirrhosis of the liver who underwent surgery other than liver transplant and applied the Mayo clinic model to predict mortality and compare with the observed mortality.We also studied the association of the observed mortality with the Child-Turcotte-Pugh(CTP)class and the model for end-stage liver disease(MELD)and model for end-stage liver disease-sodium(MELD-Na)scores.Methods:The electronic records database of our hospital was accessed to analyze the data of 133 cirrhotic patients who underwent various surgeries under general anesthesia from October 2009 to June 2017.The Mayo risk score was applied to each and used to calculate predicted mortality;the MELD and MELD-Na scores were also calculated.Telephonic interview was performed with the patients and or their relative to ascertain survival or time of death after surgery,when the information was not available from the hospital records.Results:The all-cause observed mortality rates at postoperative days 30 and 90 and at 1 year were 12%,20.3%and 26.3%respectively.The area under the receiver operating characteristic curve values for the Mayo model as a predictor of 30-day,90-day and 1-year mortality were 0.836,0.828 and 0.744 respectively.Good correlation was seen for observed mortality with CTP class and with MELD and MELD-Na scores.Conclusions:The Mayo model for predicting postoperative mortality in patients with cirrhosis of the liver demonstrated good correlation in this study.The strength of prediction of mortality by Mayo risk score calculation was similar at postoperative days 30 and 90 but decreased at 1-year after the surgery.Good correlation was seen for the observed mortality with MELD,MELD-Na and CTP scores.
