VACTERL association is an acronym that includes vertebral anomalies (V), anal atresia (A), cardiac defects (C), tracheoesophageal fistula (TEF) or esophageal atresia (EA), renal anomalies (R), and limb defects (L). Rib abnormalities have rarely been reported with the VACTERL association. The second case of VACTERL association complicated with multiple rib abnormalities will be reported in this case report. A 4-year-old girl who had been diagnosed with congenital cardiovascular disease and received surgical corrections soon after birth consulted our institution by complaining congenital scoliosis. The little girl was diagnosed with VACTERL association (congenital cardiovascular disease, scoliosis with hemivertebra and butterfly vertebra, and nephrolithiasis) and congenital multiple rib abnormalities. The Cobb angle of the main curve was 29.3° before surgery, 19.9° after surgery, and 23° at last follow-up. Multiple rib abnormalities may be seen in the VACTERL association. Clinicians should have a high index of suspicion when evaluating patients with rib abnormalities associated with VACTERL. It is extremely necessary for careful physical examination and detailed auxiliary examination to each system (including echocardiography, computed tomography, magnetic resonance imaging, and so on) when diagnosing VACTERL association. Also, recognizing and understanding the congenital multiple system malformation is important, which aids in the diagnosis of disease and accordingly plan the therapeutic interventions. Early diagnosis of congenital scoliosis with appropriate surgical intervention decreases long-term morbidity.
Vertical low-temperature centrifugal pumps were introduced as well as structure and working principle of metal diaphragm coupling,common faults and cause analysis of vertical centrifugal pumps.The relation of vertical cryogenic pump common faults with the installation condition of the coupling was discussed.In the Turpan-Hami oilfield division hydrocarbon storage and work area,in order to increase and improve the loading capacity,the metal diaphragm coupling was used to replace the fixed coupling.After the transformation,application conditions and economic advantages were analyzed.The results show that the transformation can not only save maintenance time,but also significantly lower maintenance costs,and improve the operating efficiency of pump.
[Objective] The research aimed to study the interference of nitrite in the determination of sulfides and the method of avoidance.[Method] The contents of sulfides were determined by the methylene blue spectrophotometric method and the iodometric method respectively.[Result] During the determination of sulfides with the methylene blue spectrophotometric method and the iodometric method,the determination of sulfides was seriously interfered by nitrite with high concentration.When the nitrite concentration was about 150 mg/L and the S2-concentration was 100 mg/L,the recovery rates of the two methods were 68.27% and 58.21% respectively.The experiment proved that if filter papers had been washed 3 times repeatedly when the iodometric method was used to measure sulfides,the recovery rate could up to 103.84%.[Conclusion] The research can provide reference for reducing the error of determination.
Sandstone reservoirs in Huabei Oilfield are characterized by low porosity, low permeability, high clay content, strong heterogeneity and high reservoir temperature. In order to solve the problems of rapid reaction, short effective penetration distance and secondary precipitation in conventional acid system, a new composite acid system is studied. The experimental results show that the acid-rock reaction speed of the new composite acid system is lower than that of the conventional acid system; the chelating ability of Ca2+, Fe3+ and Mg2+ ions is stronger; the corrosion rate of N80 steel is 1.57g/m2•h, far below the industry standard (10-20g/m2•h); the permeability of the core after acidizing increased by 3.5 times. This new type of composite acid system with slow reaction speed, scale inhibition and deep penetration is of great significance for acidizing low porosity and low permeability sandstone reservoirs in Huabei Oilfield.
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