Extrapancreatic necrosis volume:A new tool in acute pancreatitis severity assessment?

BACKGROUND Many scores have been suggested to assess the severity of acute pancreatitis upon onset.The extrapancreatic necrosis volume is a novel,promising score that appears to be superior to other scores investigated so far.AIM To evaluate the discriminatory power of extrapancreatic necrosis volume to identify severe cases of acute pancreatitis.METHODS A total of 123 patients diagnosed with acute pancreatitis at Institute of Gastroenterology and Hepatology,St Spiridon Hospital between January 1,2017 and December 31,2019 were analyzed retrospectively.Pancreatitis was classified according to the revised Atlanta classification(rAC)as mild,moderate,or severe.Severity was also evaluated by computed tomography and classified according to the computed tomography severity index(CTSI)and the modified CTSI(mCTSI).The results were compared with the extrapancreatic volume necrosis to establish the sensitivity and specificity of each method.RESULTS The CTSI and mCTSI imaging scores and the extrapancreatic necrosis volume were highly correlated with the severity of pancreatitis estimated by the rAC(r=0.926,P<0.001 and r=0.950,P<0.001;r=0.784,P<0.001,respectively).The correlation of C-reactive protein with severity was positive but not as strong,and was not significant(r=0.133,P=0.154).The best predictor for the assessment of severe pancreatitis was the extrapancreatic necrosis volume[area under the curve(AUC)=0.993;95%confidence interval(CI):0.981-1.005],with a 99.5%sensitivity and 99.0%specificity at a cutoff value of 167 mL,followed by the mCTSI 2007 score(AUC=0.972;95%CI:0.946-0.999),with a 98.0%sensitivity and 96.5%specificity,and the CTSI 1990 score(AUC=0.969;95%CI:0.941-0.998),with a 97.0%sensitivity and 95.0%specificity.CONCLUSION Radiological severity scores correlate strongly and positively with disease activity.Extrapancreatic necrosis volume shows the best diagnostic accuracy for severe cases.

NEW PERIODIC SOLUTIONS OF ITO'S 5th-ORDER mKdV EQUATION AND ITO'S 7th-ORDER mKdV EQUATION

Based on the modified Jocobi elliptic function expansion method and the modified extended tanh function method,a new algebraic method is presented to obtain mu ltiple travelling wave solutions for nonlinear wave equations.By using the metho d,Ito's 5th order and 7th order mKdV equations are studied in detail and more new exact Jocobi elliptic function periodic solutions are found.With modulus m→1 or m→0,these solutions degenerate into corresponding solitary wave s olutions,shock wave solutions and trigonometric function solutions.

A comparison of APACHE II,BISAP,Ranson’s score and modified CTSI in predicting the severity of acute pancreatitis based on the 2012 revised Atlanta Classification

Objective:Our aim was to prospectively compare the Accuracy of Acute Physiology and Chronic Health Evaluation(APACHE)II,Bedside Index of Severity in Acute Pancreatitis(BISAP),Ranson’s score and modified Computed Tomography Severity Index(CTSI)in predicting the severity of acute pancreatitis based on Atlanta 2012 definitions in a tertiary care hospital in northern India.Methods:Fifty patients with acute pancreatitis admitted to our hospital during the period of March 2015 to September 2016 were included in the study.APACHE II,BISAP and Ranson’s score were calculated for all the cases.Modified CTSI was also determined based on a pancreatic protocol contrast enhanced computerized tomography(CT).Optimal cut-offs for these scoring systems and the area under the curve(AUC)were evaluated based on the receiver operating characteristics(ROC)curve and these scoring systems were compared prospectively.Results:Of the 50 cases,14 were graded as severe acute pancreatitis.Pancreatic necrosis was present in 15 patients,while 14 developed persistent organ failure and 14 needed intensive care unit(ICU)admission.The AUC for modified CTSI was consistently the highest for predicting severe acute pancreatitis(0.919),pancreatic necrosis(0.993),organ failure(0.893)and ICU admission(0.993).APACHE II was the second most accurate in predicting severe acute pancreatitis(AUC 0.834)and organ failure(0.831).APACHE II had a high sensitivity for predicting pancreatic necrosis(93.33%),organ failure(92.86%)and ICU admission(92.31%),and also had a high negative predictive value for predicting pancreatic necrosis(96.15%),organ failure(96.15%)and ICU admission(95.83%).Conclusion:APACHE II is a useful prognostic scoring system for predicting the severity of acute pancreatitis and can be a crucial aid in determining the group of patients that have a high chance of need for tertiary care during the course of their illness and therefore need early resuscitation and prompt referral,especially in resource-limited developing countries.

Numerical analysis of residence time distribution of solids in a bubbling fluidized bed based on the modified structure-based drag model

The residence time distribution （RTD） of solids and the fluidized structure of a bubbling fluidized bed were investigated numerically using computational fluid dynamics simulations coupled with the modified structure-based drag model. A general comparison of the simulated results with theoretical values shows reasonable agreement. As the mean residence time is increased, the RTD initial peak intensity decreases and the RTD curve tail extends farther. Numerous small peaks on the RTD curve are induced by the back- mixing and aggregation of particles, which attests to the non-uniform flow structure of the bubbling fluidized bed. The low value of t50 results in poor contact between phases, and the complete exit age of the overflow particles is much longer for back-mixed solids and those caught in dead regions. The formation of a gulf-stream flow and back-mixing for solids induces an even wider spread of RTD.

A MODIFIED CONJUGATE DIRECTION METHOD FOR COMPUTING THE PSEUDOINVERSF

In this paper we are concerned with the modified conjugate direction method for computing the pseudoinverse by using an orthogonal basis of the range space of A. Numerical results show that the new method retains some main advantages in terms of efficiency and accuracy.