AIM: To summarize the effects of laparoscopic ethanol injection and radiofrequency ablation (L-EI-RFA), thora- coscopic (T-EI-RFA) and open-surgery assisted EI-RFA (O-EI-RFA) under general anesthesia for the treatment...AIM: To summarize the effects of laparoscopic ethanol injection and radiofrequency ablation (L-EI-RFA), thora- coscopic (T-EI-RFA) and open-surgery assisted EI-RFA (O-EI-RFA) under general anesthesia for the treatment of hepatocellular carcinoma (HCC). METHODS: Time-lag performance of RFA after ethanol injection (Time-lag PEI-RFA) was performed in all cases. The volume of coagulated necrosis and the applied en- ergy for total and per unit volume coagulated necrosis were examined in the groups treated under general (group G) or local anesthesia (group L). RESULTS: The results showed that the total applied energy and the applied energy per unit volume of whole and marginal, coagulated necrosis were significantly larger in group G than those in the group L, resulting in a larger volume of coagulated necrosis in the group G. The rate of local tumor recurrence within one year was extremely low in group G. CONCLUSION: These results suggest that EI-RFA, un- der general anesthesia, may be effective for the treat- ment of HCC because a larger quantity of ethanol and energy could be applied during treatment under pain- free condition for the patients.展开更多
Liver resections are demanding operations which can have life threatening complications although they are performed by experienced liver surgeons. Recently new technologies are applied in the field of liver surgery, h...Liver resections are demanding operations which can have life threatening complications although they are performed by experienced liver surgeons. Recently new technologies are applied in the field of liver surgery, having one goal: safer and easier liver operations. The aim of this article is to address the issue of bloodless liver resection using radiofrequency energy. Radionics, Cool-tipTM System and Tissue Link are some of the devices which are using radiofrequency energy. All information included in this article, refers to these devices in which we have personal experience in our unit of liver surgery. These devices take advantage of its unique combination of radiofrequency current and internal electrode cooling to perform sealing of the small vessels and biliary radicals. Dissection is also feasible with the cool-tip probe. For the purposes of this study patient sex, age, type of disease and type of surgical procedure in association with the duration of parenchymal transection, blood loss, length of hospital stay, morbidity and mortality were analyzed. Cool-tip RF device may provide a unique, simple and rather safe method of bloodless liver resections if used properly. It is indicated mostly in cirrhotic patients with challenging hepatectomies (segment Ⅷ, central resections). The total operative time is eliminated and the average blood loss is significantly decreased. It is important to note that this technique should not be applied near the hilum or the vena cava to avoid damage of these structures.展开更多
According to the fact that the secondary users＇ delay requirements for data transmission are not unitary in cognitive radio networks, the secondary users are divided into two classes, denoted by SU1 and SU2, respecti...According to the fact that the secondary users＇ delay requirements for data transmission are not unitary in cognitive radio networks, the secondary users are divided into two classes, denoted by SU1 and SU2, respectively. It is assumed that SU1 has a higher priority to occupy the primary users＇ unutilized channels than SU2. A preemptive resume priority M/G/1 queuing network is used to model the multiple spectrum handoffs processing. By using a state transition probability matrix and a cost matrix, the average cumulative delays of SU1 and SU2 are calculated, respectively. Numerical results show that the more the primary user＇s traffic load, the more rapidly the SU2＇s cumulative handoff delay grows. Compared with the networks where secondary users are unitary, the lower the SUI＇s arrival rate, the more obviously both SUI＇s and SU2＇s handoff delays decrease. The admission access regions limited by the maximum tolerable delay can also facilitate the design of admission control rules for graded secondary users.展开更多
The influence of summer monsoon on tropical cyclone (TC) genesis over the Bay of Bengal (BoB) is explored using an empirical genesis potential (GP) index. The annual cycle of cyclogenesis frequency over the BoB shows ...The influence of summer monsoon on tropical cyclone (TC) genesis over the Bay of Bengal (BoB) is explored using an empirical genesis potential (GP) index. The annual cycle of cyclogenesis frequency over the BoB shows an asymmetric bimodal pattern with the maximum genesis number appearing in late October and the second largest in early May. The two peaks correspond to the withdrawal and onset of the BoB summer monsoon, respectively. The semimonthly GP index calculated without TC days over the BoB is consistent with TC genesis frequency, indicating that the index captures the monsoon-induced changes in the environment that are responsible for the seasonal variation of TC genesis frequency. Of the four environmental variables (i.e., low-level vorticity, mid-level relative humidity, potential intensity, and vertical wind shear) that enter into the GP index, the potential intensity makes the largest contribution to the bimodal distribution, followed by vertical wind shear due to small wind speed during the summer monsoon onset and withdrawal. The difference in TC genesis frequency between autumn and late spring is mainly owing to the relative humid-ity difference because a divergence (convergence) of horizontal moisture flux associated with cold dry northerlies (warm wet wester-lies) dominates the BoB in late spring (autumn).展开更多
AIM:To evaluate the comparative therapeutic efficacy of radiofrequency ablation (RFA) and hepatic resection (HR) for solitary colorectal liver metastases (CLM).METHODS:A literature search was performed to identify com...AIM:To evaluate the comparative therapeutic efficacy of radiofrequency ablation (RFA) and hepatic resection (HR) for solitary colorectal liver metastases (CLM).METHODS:A literature search was performed to identify comparative studies reporting outcomes for both RFA and HR for solitary CLM.Pooled odds ratios (OR) with 95% confidence intervals (95% CI) were calculated using either the fixed effects model or random effects model.RESULTS:Seven nonrandomized controlled trials studies were included in this analysis.These studies included a total of 847 patients:273 treated with RFA and 574 treated with HR.The 5 years overall survival rates in the HR group were significantly better than those in the RFA group (OR:0.41,95% CI:0.22-0.90,P=0.008).RFA had a higher rate of local intrahe-patic recurrence compared to HR (OR:4.89,95% CI:1.73-13.87,P=0.003).No differences were found between the two groups with respect to postoperative morbidity and mortality.CONCLUSION:HR was superior to RFA in the treatment of patients with solitary CLM.However,the findings have to be carefully interpreted due to the lower level of evidence.展开更多
文摘AIM: To summarize the effects of laparoscopic ethanol injection and radiofrequency ablation (L-EI-RFA), thora- coscopic (T-EI-RFA) and open-surgery assisted EI-RFA (O-EI-RFA) under general anesthesia for the treatment of hepatocellular carcinoma (HCC). METHODS: Time-lag performance of RFA after ethanol injection (Time-lag PEI-RFA) was performed in all cases. The volume of coagulated necrosis and the applied en- ergy for total and per unit volume coagulated necrosis were examined in the groups treated under general (group G) or local anesthesia (group L). RESULTS: The results showed that the total applied energy and the applied energy per unit volume of whole and marginal, coagulated necrosis were significantly larger in group G than those in the group L, resulting in a larger volume of coagulated necrosis in the group G. The rate of local tumor recurrence within one year was extremely low in group G. CONCLUSION: These results suggest that EI-RFA, un- der general anesthesia, may be effective for the treat- ment of HCC because a larger quantity of ethanol and energy could be applied during treatment under pain- free condition for the patients.
文摘Liver resections are demanding operations which can have life threatening complications although they are performed by experienced liver surgeons. Recently new technologies are applied in the field of liver surgery, having one goal: safer and easier liver operations. The aim of this article is to address the issue of bloodless liver resection using radiofrequency energy. Radionics, Cool-tipTM System and Tissue Link are some of the devices which are using radiofrequency energy. All information included in this article, refers to these devices in which we have personal experience in our unit of liver surgery. These devices take advantage of its unique combination of radiofrequency current and internal electrode cooling to perform sealing of the small vessels and biliary radicals. Dissection is also feasible with the cool-tip probe. For the purposes of this study patient sex, age, type of disease and type of surgical procedure in association with the duration of parenchymal transection, blood loss, length of hospital stay, morbidity and mortality were analyzed. Cool-tip RF device may provide a unique, simple and rather safe method of bloodless liver resections if used properly. It is indicated mostly in cirrhotic patients with challenging hepatectomies (segment Ⅷ, central resections). The total operative time is eliminated and the average blood loss is significantly decreased. It is important to note that this technique should not be applied near the hilum or the vena cava to avoid damage of these structures.
基金The National Natural Science Foundation of China(No.60972026,61271207)the National Science and Technology Major Project(No.2010ZX03006-002-01)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education(No.20090092110009)the Specialized Development Foundation for the Achievement Transformation of Jiangsu Province(No.BA2010023)
文摘According to the fact that the secondary users＇ delay requirements for data transmission are not unitary in cognitive radio networks, the secondary users are divided into two classes, denoted by SU1 and SU2, respectively. It is assumed that SU1 has a higher priority to occupy the primary users＇ unutilized channels than SU2. A preemptive resume priority M/G/1 queuing network is used to model the multiple spectrum handoffs processing. By using a state transition probability matrix and a cost matrix, the average cumulative delays of SU1 and SU2 are calculated, respectively. Numerical results show that the more the primary user＇s traffic load, the more rapidly the SU2＇s cumulative handoff delay grows. Compared with the networks where secondary users are unitary, the lower the SUI＇s arrival rate, the more obviously both SUI＇s and SU2＇s handoff delays decrease. The admission access regions limited by the maximum tolerable delay can also facilitate the design of admission control rules for graded secondary users.
基金supported by the National Basic Research Program of China(973Program:2012CB955604)National Natural Science Foundation of China(No.40975038,40830106)the CMA Program(GYHY200906008)
文摘The influence of summer monsoon on tropical cyclone (TC) genesis over the Bay of Bengal (BoB) is explored using an empirical genesis potential (GP) index. The annual cycle of cyclogenesis frequency over the BoB shows an asymmetric bimodal pattern with the maximum genesis number appearing in late October and the second largest in early May. The two peaks correspond to the withdrawal and onset of the BoB summer monsoon, respectively. The semimonthly GP index calculated without TC days over the BoB is consistent with TC genesis frequency, indicating that the index captures the monsoon-induced changes in the environment that are responsible for the seasonal variation of TC genesis frequency. Of the four environmental variables (i.e., low-level vorticity, mid-level relative humidity, potential intensity, and vertical wind shear) that enter into the GP index, the potential intensity makes the largest contribution to the bimodal distribution, followed by vertical wind shear due to small wind speed during the summer monsoon onset and withdrawal. The difference in TC genesis frequency between autumn and late spring is mainly owing to the relative humid-ity difference because a divergence (convergence) of horizontal moisture flux associated with cold dry northerlies (warm wet wester-lies) dominates the BoB in late spring (autumn).
文摘AIM:To evaluate the comparative therapeutic efficacy of radiofrequency ablation (RFA) and hepatic resection (HR) for solitary colorectal liver metastases (CLM).METHODS:A literature search was performed to identify comparative studies reporting outcomes for both RFA and HR for solitary CLM.Pooled odds ratios (OR) with 95% confidence intervals (95% CI) were calculated using either the fixed effects model or random effects model.RESULTS:Seven nonrandomized controlled trials studies were included in this analysis.These studies included a total of 847 patients:273 treated with RFA and 574 treated with HR.The 5 years overall survival rates in the HR group were significantly better than those in the RFA group (OR:0.41,95% CI:0.22-0.90,P=0.008).RFA had a higher rate of local intrahe-patic recurrence compared to HR (OR:4.89,95% CI:1.73-13.87,P=0.003).No differences were found between the two groups with respect to postoperative morbidity and mortality.CONCLUSION:HR was superior to RFA in the treatment of patients with solitary CLM.However,the findings have to be carefully interpreted due to the lower level of evidence.
