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In order to improve the tribological properties of aluminum alloys, the finite element method was used to simulate the bearing capacity of the lubricant film between the friction pairs of three different textures, such as square pit array, strip groove array and the combined texture array of pits and strip grooves. The influence of different texture sizes on the bearing capacity of oil film was explored. Simulation results show that the lubricant film on combined texture array of pits and strip grooves has the best bearing capacity. The texture array of square pits and strip grooves with regular morphology were prepared on the surface of aluminum alloy specimens by pulsed Nd: YAC laser. The friction properties of combined texture array specimens were tested by the CFT-I high-speed reciprocating friction and wear tester to study the effect of texture geometry on the tribological properties between the contact surfaces of friction pairs. The morphologies of the wear surface of the specimens were observed by the microscopy system. The test results show that compared with the non-textured surface, the average friction coefficient of the combined texture surface is significantly reduced, and the fluctuation range of friction coefficient is small. The specimen with texture size of 80 µm shows the lowest friction coefficient. The variation regulations of wear mark depth on matrix surface by test and the lift coefficient of lubricating oil by simulation are similar, which provides a certain theoretical basis for the design of micro-texture parameters. [ABSTRACT FROM AUTHOR]

Through continuous development, metabolic and bariatric surgery (MBS) has become widely recognized in academic and medical circles. In China, the volume of MBS operations has increased year by year. Therapeutic goals of MBS have evolved from treating obesity to treating Type 2 diabetes mellitus, and further to treating a series of obesity-associated metabolic diseases (including conditions in the endocrine system, circulatory system, respiratory system, reproductive system, and etc). Surgical approach of MBS has also been evolving continuously. Currently the common surgical procedures include laparoscopic Roux-en-Y gastric bypass (LRYGB), laparoscopic sleeve gastrectomy (LSG), laparoscopic adjustable gastric banding (LAGB) and bilio-pancreatic diversion with duodenal switch (BPD-DS). All surgical procedures have pros and cons, and the choice of surgical procedures should be based on the conditions of patients, the surgeon's technical ability, and benefits and operative risks. With the development of MBS, the proportions of different surgical procedures also changed in China. In recent five years, the proportion of AGB has decreased continuously and LAGB is no longer a common procedure. The proportion of LSG has increased rapidly, rising from 9% in 2010 to 55% in 2015. The proportion of RYGB has increased from 57% to 64% between 2010 and 2013, and remained at 45% afterwards. Since 2010, most MBS operations are laparoscopic surgery. 3D Laparoscopic surgery, laparoendoscopic single-site surgery and da Vinci Robotic Surgery have also been introduced in MBS. This review discusses the status quo and changes of MBS in china, as well as the new technology in MBS, aiming to strengthen the information and comprehension of MBS in china.

For the vast majority of morbidly obese patients, surgical treatment remains the only effective way proven to maintain weight loss. Currently adjustable gastric banding (AGB), sleeve gastrectomy (SG), Roux-en-Y gastric bypass(RYGB) are the methods which are recognized as safe, reliable, effective for weight loss, and has been widely used. Along with the increase in the volume of bariatric operations, patients whose primary bariatric operation is not ideal and who need revision surgery are also increasing. Weight loss failure and postoperative complications are two of the main indications for revisional operation. A series of data indicate that revisional operation is an effective treatment for unsuccessful weight loss and complications of primary operation. Surgeons should choose reasonable, correct operation refer to the initial bariatric operation and results. For most patients, the benefits overweigh the risks.