Duodenal stenosis resulting from a preduodenal portal vein and an operation for scoliosis

A preduodenal portal vein （PDPV） is known to be a rare cause of duodenal stenosis. We treated a 22-yearold male patient with malnutrition as a result of PDPV and a previously performed operation for scoliosis, who showed an improvement in quality of life after being treated with a combination of nutritional support and surgery. The patient with PDPV had been admitted to our department with duodenal stenosis, ranging from the first to third portions. He had suffered from vomiting since 1 year of age, and he developed malnutrition during the last 6-too period after orthopedic surgery for scoliosis. The stenosis was related to both the PDPV and the previously performed operation for scoliosis. After receiving nutritional support for 6 mo, a gastrojejunostomy with Braun＇s anastomosis for the first portion and a duodenojejunostomy for the second and third portions were performed. The postoperative course was almost uneventful. Three months later, he was discharged and able to attend university. In patients with widespread duodenal stenosis, there may be a complicated cause,such as PDPV and duodenal stretching induced by previous spinal surgery.

VISUALIZATION OF TURBULENT REACTIVE JET BY USING DIRECT NUMERICAL SIMULATION

Direct numerical simulation(DNS)of turbulent planar jet with a second-order chemical reaction(A+B→R)is performed to investigate the processes of mixing and chemical reactions in spatially developing turbulent free shear flows.Reactant A is premixed into the jet flow,and reactant B is premixed into the ambient flow.DNS is performed at three different Damk¨ohler numbers(Da=0.1,1,and 10).Damk¨ohler number is a ratio of a time scale of a flow to that of chemical reactions,and in this study,the large Da means a fast chemical reaction,and the small Da means a slow chemical reaction.The visualization of velocity field shows that the jet flow is developed by entraining the ambient fluid.The visualization of concentration of reactant A shows that concentration of reactant A for Da=1 and 10 becomes very small in the downstream region because the chemical reaction consumes the reactants and reactant A is diffused with the jet development.By comparison of the profiles of chemical reaction rate and concentration of product R,it is found that product R for Da=10 is produced by the chemical reaction at the interface between the jet and the ambient fluids and is diffused into the jet flow,whereas product R for Da=0.1 is produced in the jet flow after reactants A and B are well mixed.