Optimization of Fixture Number in Large Thin-Walled Parts Assembly Based on IPSO

There are lots of researches on fixture layout optimization for large thin-walled parts.Current researches focus on the positioning problem,i.e.,optimizing the positions of a constant number of fixtures.However,how to determine the number of fixtures is ignored.In most cases,the number of fixtures located on large thin-walled parts is determined based on engineering experience,which leads to huge fixture number and extra waste.Therefore,this paper constructs an optimization model to minimize the number of fixtures.The constraints are set in the optimization model to ensure that the part deformation is within the surface profile tolerance.In addition,the assembly gap between two parts is also controlled.To conduct the optimization,this paper develops an improved particle swarm optimization(IPSO)algorithm by integrating the shrinkage factor and adaptive inertia weight.In the algorithm,particles are encoded according to the fixture position.Each dimension of the particle is assigned to a sub-region by constraining the optional position range of each fixture to improve the optimization efficiency.Finally,a case study on ship curved panel assembly is provided to prove that our method can optimize the number of fixtures while meeting the assembly quality requirements.This research proposes a method to optimize the number of fixtures,which can reduce the number of fixtures and achieve deformation control at the same time.

Novel subtype of obesity influencing the outcomes of sleeve gastrectomy:Familial aggregation of obesity

BACKGROUND Differences in the preoperative characteristics and weight loss outcomes after sleeve gastrectomy(SG)between patients with familial aggregation of obesity(FAO)and patients with sporadic obesity(SO)have not been elucidated.AIM To explore the impact of SG on weight loss and the alleviation of obesity-related comorbidities in individuals with FAO.METHODS A total of 193 patients with obesity who underwent SG were selected.Patients with FAO/SO were matched 1:1 by propensity score matching and were categorized into 4 groups based on the number of first-degree relatives with obesity(1 SO vs 1FAO,2SO vs 2FAO).The baseline characteristics,weight loss outcomes,prevalence of obesity-related comorbidities and incidence of major surgeryrelated complications were compared between groups.RESULTS We defined FAO as the presence of two or more first-degree relatives with obesity.Patients with FAO did not initially show significant differences in baseline data,short-term postoperative weight loss,or obesity-related comorbidities when compared to patients with SO preoperatively.However,distinctions between the two groups became evident at the two-year mark,with statistically significant differences in both percentage of total weight loss(P=0.006)and percentage of excess weight loss(P<0.001).The FAO group exhibited weaker remission of type 2 diabetes mellitus(T2DM)(P=0.031),hyperlipidemia(P=0.012),and non-alcoholic fatty liver disease(NAFLD)(P=0.003)as well as a lower incidence of acid reflux(P=0.038).CONCLUSION FAO patients is associated with decreased mid-to-long-term weight loss outcomes;the alleviation of T2DM,hyperlipidemia and NAFLD;and decreased incidence of acid reflux postoperatively.

Development of Fixture Layout Optimization for Thin-Walled Parts:A Review

An increasing number of researchers have researched fixture layout optimization for thin-walled part assembly during the past decades.However,few papers systematically review these researches.By analyzing existing literature,this paper summarizes the process of fixture layout optimization and the methods applied.The process of optimization is made up of optimization objective setting,assembly variation/deformation modeling,and fixture layout optimization.This paper makes a review of the fixture layout for thin-walled parts according to these three steps.First,two different kinds of optimization objectives are introduced.Researchers usually consider in-plane variations or out-of-plane deformations when designing objectives.Then,modeling methods for assembly variation and deformation are divided into two categories:Mechanism-based and data-based methods.Several common methods are discussed respectively.After that,optimization algorithms are reviewed systematically.There are two kinds of optimization algorithms:Traditional nonlinear programming and heuristic algorithms.Finally,discussions on the current situation are provided.The research direction of fixture layout optimization in the future is discussed from three aspects:Objective setting,improving modeling accuracy and optimization algorithms.Also,a new research point for fixture layout optimization is discussed.This paper systematically reviews the research on fixture layout optimization for thin-walled parts,and provides a reference for future research in this field.

Meter-Scale Thin-Walled Structure with Lattice Infill for Fuel Tank Supporting Component of Satellite:Multiscale Design and Experimental Verification

Lightweight thin-walled structures with lattice infill are widely desired in satellite for their high stiffness-to-weight ratio and superior buckling strength resulting fromthe sandwich effect.Such structures can be fabricated bymetallic additive manufacturing technique,such as selective laser melting(SLM).However,the maximum dimensions of actual structures are usually in a sub-meter scale,which results in restrictions on their appliance in aerospace and other fields.In this work,a meter-scale thin-walled structure with lattice infill is designed for the fuel tank supporting component of the satellite by integrating a self-supporting lattice into the thickness optimization of the thin-wall.The designed structure is fabricated by SLM of AlSi10Mg and cold metal transfer welding technique.Quasi-static mechanical tests and vibration tests are both conducted to verify the mechanical strength of the designed large-scale lattice thin-walled structure.The experimental results indicate that themeter-scale thin-walled structure with lattice infill could meet the dimension and lightweight requirements of most spacecrafts.

An electromagnetic semi-active dynamic vibration absorber for thin-walled workpiece vibration suppression in mirror milling

As critical components of aircraft skins and rocket fuel storage tank shells,large thin-walled workpieces are susceptible to vibration and deformation during machining due to their weak local stiffness.To address these challenges,we propose a novel tunable electromagnetic semi-active dynamic vibration absorber(ESADVA),which integrates with a magnetic suction follower to form a followed ESADVA(follow-ESADVA)for mirror milling.This system combines a tunable magnet oscillator with a follower,enabling real-time vibration absorption and condition feedback throughout the milling process.Additionally,the device supports self-sensing and frequency adjustment by providing feedback to a linear actuator,which alters the distance between magnets.This resolves the traditional issue of being unable to directly monitor vibration at the machining point due to space constraints and tool interference.The frequency shift characteristics and vibration absorption performance are comprehensively investigated.Theoretical and experimental results demonstrate that the prototyped follow-ESADVA achieves frequency synchronization with the milling tool,resulting in a vibration suppression rate of approximately 47.57%.Moreover,the roughness of the machined surface decreases by18.95%,significantly enhancing the surface quality.The results of this work pave the way for higher-quality machined surfaces and a more stable mirror milling process.

Functional Roux-en-Y Gastric Bypass (F-RYGB), with Preservation of Duodenal Access: Report of Two Revisional Cases of Sleeve Gastrectomy

Objective: This case report aimed to demonstrate a possible neuromuscular effect of Latarjet nerves transection or truncal vagotomy, in association with sleeve gastrectomy plus antrojejunostomy, in order to reproduce a Roux-en-Y gastric bypass (RYGB) mechanistic principles, in patients with previous Sleeve Gastrectomy (SG) who had had weight regain, with or without concomitant gastroesophageal reflux disease (GERD). Background: Sleeve gastrectomy (SG) is one of the most frequently performed bariatric operations worldwide. Nevertheless, weight regain and gastroesophageal reflux disease (GERD) have been consistently demonstrated, in association with this technique, which may require a revisional procedure. RYGB is an option in such a situation but, implies in gastrointestinal exclusions, which represents a shortcoming of this revision. Surpassing this inconvenient would be of great value for the patients. Methods: We describe herein two cases of SG revision for weight regain and GERD, with a follow-up of one year. Gastroesophageal reflux disease was evaluated by validated questionnaire, upper endoscopy, seriography, high resolution manometry (HRM) and impedance pHmetry (I-pHmetry), in the pre and postoperative periods. A re-Sleeve Gastrectomy with antrojejunal anastomosis was done in both cases, after informed consents. The Latarjet nerves were transected in one case, due to a bleeding in the left gastric vessels and a truncal vagotomy was required in the other, to appropriately treat an associated hiatal hernia. Results: In the postoperative evaluation it was observed a pyloric spasm in both cases, during seriography and endoscopy, kept until the one-year follow-up. There was unidirectional contrast flow to the gastrointestinal anastomosis, filling the jejunal limb, in radiologic contrast study. No contrast passed through the pylorus. Nonetheless, the duodenum was kept endoscopically accessible. In the one-year evaluation, weight loss was adequate and GERD resolution was obtained in both cases, confirmed by endoscopic and functional esophageal assessment, together with symptoms questionnaire. Conclusion: The association of Latarjet nerves sectioning or truncal vagotomy with re-sleeve gastrectomy plus gastrointestinal anastomosis (antrojejunal), in a revision for a failed sleeve, can represent a technical approach, to reproduce RYGB results, without exclusions and with duodenum endoscopic accessibility maintenance. It maybe could be applied for primary surgeries. Additional studies are necessary to confirm this hypothesis.

Numerical Analysis of Cold-Formed Thin-Walled Steel Short Columns with Pitting Corrosion during Bridge Construction

Pitting corrosion is harmful during bridge construction,which will lead to uneven roughness of steel surfaces and reduce the thickness of steel.Hence,the effect of pitting corrosion on the mechanical properties of cold-formed thin-walled steel stub columns is studied,and the empirical formulas are established through regression fitting to predict the ultimate load of web and flange under pitting corrosion.In detail,the failure modes and load-displacement curves of specimens with different locations,area ratios,and depths are obtained through a large number of non-linear finite element analysis.As for the specimens with pitting corrosion on the web,all the specimens are subject to local buckling failure,and the failure mode will not change with pitting corrosion,but the failure location will change with pitting corrosion location;the size,location,and area ratio of pitting corrosion have little influence on the ultimate load of cold-formed thin-walled steel short columns,but the loss rate of pitting corrosion section area has a greater impact on the ultimate bearing capacity.As for the specimen with flange pitting corrosion,the location and area ratio of pitting corrosion have less influence on the ultimate load of cold-formed thin-walled steel short columns,and the section area loss rate has greater influence on the ultimate bearing capacity;the impact of web pitting corrosion on the ultimate load is greater than that of flange pitting corrosion under the same condition of pitting corrosion section area.The prediction formulas of limit load which are suitable for pitting corrosion of web and flange are established,which can provide a reference for performance evaluation of corroded cold-formed thin-walled steel.

Association between operative position and postoperative nausea and vomiting in patients undergoing laparoscopic sleeve gastrectomy

BACKGROUND Bariatric surgery is one of the most effective ways to treat morbid obesity,and postoperative nausea and vomiting(PONV)is one of the common complications after bariatric surgery.At present,the mechanism of the high incidence of PONV after weight-loss surgery has not been clearly explained,and this study aims to investigate the effect of surgical position on PONV in patients undergoing bariatric surgery.AIM To explore the effect of the operative position during bariatric surgery on PONV.METHODS Data from obese patients,who underwent laparoscopic sleeve gastrectomy(LSG)in the authors’hospital between June 2020 and February 2022 were divided into 2 groups and retrospectively analyzed.Multivariable logistic regression analysis and the t-test were used to study the influence of operative position on PONV.RESULTS There were 15 cases of PONV in the supine split-leg group(incidence rate,50%)and 11 in the supine group(incidence rate,36.7%)(P=0.297).The mean operative duration in the supine split-leg group was 168.23±46.24 minutes and 140.60±32.256 minutes in the supine group(P<0.05).Multivariate analysis revealed that operative position was not an independent risk factor for PONV(odds ratio=1.192,95%confidence interval:0.376-3.778,P=0.766).CONCLUSION Operative position during LSG may affect PONV;however,the difference in the incidence of PONV was not statistically significant.Operative position should be carefully considered for obese patients before surgery.

Research on Sleeve Grouting Density Detection Based on the Impact Echo Method

Grouting defects are an inherent challenge in construction practices,exerting a considerable impact on the operational structural integrity of connections.This investigation employed the impact-echo technique for the detection of grouting anomalies within connections,enhancing its precision through the integration of wavelet packet energy principles for damage identification purposes.A series of grouting completeness assessments were meticulously conducted,taking into account variables such as the divergent material properties of the sleeves and the configuration of adjacent reinforcement.The findings revealed that:(i)the energy distribution for the highstrength concrete cohort predominantly occupied the frequency bands 42,44,45,and 47,whereas for other groups,it was concentrated within the 37 to 40 frequency band;(ii)the delineation of empty sleeves was effectively discernible by examining the wavelet packet energy ratios across the spectrum of frequencies,albeit distinguishing between sleeves with 50%and full grouting density proved challenging;and(iii)the wavelet packet energy analysis yielded variable detection outcomes contingent on the material attributes of the sleeves,demonstrating heightened sensitivity when applied to ultrahigh-performance concrete matrices and GFRP-reinforced steel bars.

Left lower lobe sleeve resection for the clear cell variant of pulmonary mucoepidermoid carcinoma:A case report

BACKGROUND Pulmonary mucoepidermoid carcinoma(PMEC)is a rare malignancy that arises from minor salivary glands within the tracheobronchial tree.The clear cell variant of PMEC is exceptionally uncommon and presents notable diagnostic challenges,primarily attributable to its morphological similarity to other tumors containing clear cells.CASE SUMMARY A 22-year-old male,formerly in good health,came in with a two-month duration of persistent cough and production of sputum.Subsequent imaging and bronchoscopy examinations revealed a 2 cm tumor in the distal left main bronchus,which resulted in complete atelectasis of the left lung.Further assessment via positron emission tomography/computed tomography scans and endoscopic biopsy confirmed the primary malignant nature of the tumor,charac-terized by clear cell morphology in most of the tumor cells.The patient underwent a left lower lobe sleeve resection accompanied by systematic mediastinal lymph node dissection.Molecular pathology analysis subsequently revealed a CRTC3-MAML2 gene fusion,leading to a definitive pathological diagnosis of the clear cell variant of PMEC,staged as T2N0M0.After surgery,the patient experienced a smooth recovery and exhibited no signs of recurrence during the one-and-a-half-year follow-up period.CONCLUSION This article describes an unusual case of a clear cell variant of PMEC characterized by the presence of a CRTC3-MAML2 gene fusion in a 22-year-old male.The patient underwent successful left lower lobe sleeve resection.This case underscores the distinctive challenges associated with diagnosing and treating this uncommon malignancy,underscoring the importance of precise diagnosis and personalized treatment strategies.

Nerve growth factor-basic fibroblast growth factor poly-lactide co-glycolid sustained-release microspheres and the small gap sleeve bridging technique to repair peripheral nerve injury

We previously prepared nerve growth factor poly-lactide co-glycolid sustained-release microspheres to treat rat sciatic nerve injury using the small gap sleeve technique.Multiple growth factors play a synergistic role in promoting the repair of peripheral nerve injury;as a result,in this study,we added basic fibroblast growth factors to the microspheres to further promote nerve regeneration.First,in an in vitro biomimetic microenvironment,we developed and used a drug screening biomimetic microfluidic chip to screen the optimal combination of nerve growth factor/basic fibroblast growth factor to promote the regeneration of Schwann cells.We found that 22.56 ng/mL nerve growth factor combined with 4.29 ng/mL basic fibroblast growth factor exhibited optimal effects on the proliferation of primary rat Schwann cells.The successfully prepared nerve growth factor-basic fibroblast growth factor-poly-lactide-co-glycolid sustained-release microspheres were used to treat rat sciatic nerve transection injury using the small gap sleeve bridge technique.Compared with epithelium sutures and small gap sleeve bridging alone,the small gap sleeve bridging technique combined with drug-free sustained-release microspheres has a stronger effect on rat sciatic nerve transfection injury repair at the structural and functional level.

Boundary Element Analysis forModeⅢCrack Problems of Thin-Walled Structures from Micro-to Nano-Scales

This paper develops a new numerical framework for modeⅢcrack problems of thin-walled structures by integrating multiple advanced techniques in the boundary element literature.The details of special crack-tip elements for displacement and stress are derived.An exponential transformation technique is introduced to accurately calculate the nearly singular integral,which is the key task of the boundary element simulation of thin-walled structures.Three numerical experiments with different types of cracks are provided to verify the performance of the present numerical framework.Numerical results demonstrate that the present scheme is valid for modeⅢcrack problems of thin-walled structures with the thickness-to-length ratio in the microscale,even nanoscale,regime.

Endoscopic sleeve gastroplasty in class Ⅲ obesity:Efficacy, safety, and durability outcomes in 404 consecutive patients

BACKGROUND Endoscopic sleeve gastroplasty(ESG) is an effective therapy for class Ⅰ-Ⅱ obesity, but there are knowledge gaps in the published literature about its implementation in patients with class Ⅲ obesity [body mass index(BMI) ≥ 40 kg/m2].AIM To evaluate the safety, clinical efficacy, and durability of ESG in adults with class Ⅲ obesity.METHODS This was a retrospective cohort study that used prospectively collected data on adults with BMI ≥ 40 kg/m2who underwent ESG and longitudinal lifestyle counseling at two centers with expertise in endobariatric therapies from May 2018-March 2022. The primary outcome was total body weight loss(TBWL) at 12 mo. Secondary outcomes included changes in TBWL, excess weight loss(EWL) and BMI at various time points up to 36 mo, clinical responder rates at 12 and 24 mo, and comorbidity improvement. Safety outcomes were reported through the study duration. One-way ANOVA test was performed with multiple Tukey pairwise comparisons for TBWL, EWL, and BMI over the study duration.RESULTS 404 consecutive patients(78.5% female, mean age 42.9 years, mean BMI 44.8 ± 4.7 kg/m2) were enrolled. ESGs were performed using an average of 7 sutures, over 42 ± 9 min, and with 100% technical success. TBWL was 20.9 ± 6.2% at 12 mo, 20.5 ± 6.9% at 24 mo, and 20.3 ± 9.5% at 36 mo. EWL was 49.6 ± 15.1% at 12 mo, 49.4 ± 16.7% at 24 mo, and 47.1 ± 23.5% at 36 mo. There was no difference in TBWL at 12, 15, 24, and 36 mo from ESG. TBWL exceeding 10%, 15%, and 20% was achieved by 96.7%, 87.4%, and 55.6% of the cohort at 12 mo, respectively. Of the cohort with the relevant comorbidity at time of ESG, 66.1% had improvement in hypertension, 61.7% had improvement in type Ⅱ diabetes, and 45.1% had improvement in hyperlipidemia over study duration. There was one instance of dehydration requiring hospitalization(0.2% serious adverse event rate).CONCLUSION When combined with longitudinal nutritional support, ESG induces effective and durable weight loss in adults with class Ⅲ obesity, with improvement in comorbidities and an acceptable safety profile.

Numerical study on erosion behavior of sliding sleeve ball seat for hydraulic fracturing based on experimental data

The sleeve sealing ball seat is one of the important components in the multistage fracturing process of horizontal wells.The erosion and wear of the surface will decrease the sealing performance of the fracturing ball and the ball seat.This leads to pressure leakage during the fracturing process and fracturing failure.In this paper,combined with the actual ball seat materials and working conditions during the fracturing process,the erosion tests of ductile iron and tungsten carbide materials under different erosion speeds,angles,and mortar concentrations are carried out.Then the erosion test results were analyzed by mathematical fitting,and a set of erosion models suitable for sliding sleeve setting ball seat materials were innovatively established.For the first time,this paper combines the erosion model obtained from the experiment and the computational fluid dynamics(CFD)with Fluent software to simulate the erosion of the ball seat.Based on the simulation results,the morphology of the sliding sleeve seat ball after erosion is predicted.Through analysis of the test and simulation results,it is showed that the erosion rate of tungsten carbide material is lower and the wear resistance is better under the condition of small angle erosion.This research can offer a strong basis for fracturing site selection,surface treatment methods,and prediction of failure time of ball seats.

Geometric Accuracy and Energy Absorption Characteristics of 3D Printed Continuous Ramie Fiber Reinforced Thin-Walled Composite Structures

The application of continuous natural fibers as reinforcement in composite thin-walled structures offers a feasible approach to achieve light weight and high strength while remaining environmentally friendly.In addition,additive manufacturing technology provides a favorable process foundation for its realization.In this study,the printability and energy absorption properties of 3D printed continuous fiber reinforced thin-walled structures with different configurations were investigated.The results suggested that a low printing speed and a proper layer thickness would mitigate the printing defects within the structures.The printing geometry accuracy of the structures could be further improved by rounding the sharp corners with appropriate radii.This study successfully fabricated structures with vari-ous configurations characterized by high geometric accuracy through printing parameters optimization and path smoothing.Moreover,the compressive property and energy absorption characteristics of the structures under quasi-static axial compression were evaluated and compared.It was found that all studied thin-walled structures exhibited progressive folding deformation patterns during compression.In particular,energy absorption process was achieved through the combined damage modes of plastic deformation,fiber pullout and delamination.Furthermore,the com-parison results showed that the hexagonal structure exhibited the best energy absorption performance.The study revealed the structure-mechanical property relationship of 3D printed continuous fiber reinforced composite thin-walled structures through the analysis of multiscale failure characteristics and load response,which is valuable for broadening their applications.

Laparoscopic Sleeve Gastrectomy following Pylorus-Preserving Pancreaticoduodenectomy

Background: A 35-year-old married female (68 kg, 150 cm, BMI: 30.2) with pancreatic divisum complicated chronic pancreatitis and underwent pylorus-preserving pancreaticoduodenectomy in 2010. After that, her condition was well. However, body weight gained progressively to 76 kg (BMI: 33.7) and hypertension developed. During these two years, tried exercise and medication control for hypertension, but in vain. She received a laparoscopic sleeve gastrectomy in October 2013. The post-operative course was uneventful. Methods: We applied three ports for laparoscopic operation, including two 12 mm and one 5 mm trocars. The liver was not needed to be elevated due to adhesion. The operative time was 75 minutes. Results: The patient’s body weight was 10 kg reduced in the first two months and reduced to 59 kg 6 months later. Conclusions: We report a case that received laparoscopic sleeve gastrectomy following pylorus-preserving pancreaticoduodenectomy due to pancreatic divisum. This case encourages us to extend the indication of laparoscopic sleeve gastrectomy.

Effect of laparoscopic sleeve gastrectomy on related variables of obesity complicated with polycystic ovary syndrome

BACKGROUND Polycystic ovary syndrome(PCOS)is closely related to obesity,and weight loss can significantly improve the metabolic,endocrine and reproductive functions of obese individuals with PCOS.However,the efficacy of laparoscopic sleeve gastrectomy(LSG)for obesity with PCOS are unclear.AIM The purpose of the study was to investigate the effect of LSG on related variables in obese patients with PCOS.METHODS A retrospective analysis was performed on 32 obese patients with PCOS who received LSG treatment at the Third Hospital of Shanxi Medical University from 2013 to 2020.The changes in anthropometric indices,insulin,testosterone,estradiol,follicle stimulating hormone(FSH),luteinizing hormone(LH),menstrual cycle and LH/FSH ratio before and 1 mo,3 mo,6 mo and 12 mo after the operation were statistically analyzed.RESULTS At 1 mo,3 mo,6 mo and 12 mo after surgery,the anthropometric indices,such as body weight and body mass index,of all patients were lower than those before the operation.The percentage excess weight loss(EWL%)at 1 mo,3 mo,6 mo and 1 year of follow-up were 25,40,46 and 65,respectively.The PCOS-related indices,such as insulin,testosterone,estradiol,follicle stimulating hormone(FSH),luteinizing hormone(LH)and menstrual cycle,were improved to varying degrees.During the 1-year follow-up,the average serum testosterone decreased from preoperative 0.72 ng/mL to 0.43 ng/mL(P<0.05),average fasting insulin level(9.0 mIU/mL,preoperative 34.2 mil,LH level,4.4 mIU/mL,preoperative 6.1 mIU/mL).The level of FSH(3.8 U/L,4.8 U/p0.05)and the ratio of LH/FSH(0.7,1.3/p0.05)were more relieved than those before surgery.During the postoperative follow-up,it was found that the menstrual cycle of 27 patients(nasty 27)returned to normal,and 6 patients(18%)who intended to become pregnant became pregnant within 1 year after surgery.CONCLUSION The weight loss effect of LSG is obvious and affirmative,and the endocrine index of obese patients with PCOS is also improved to some extent,although the mechanism is not clear.Laparoscopic sleeve gastrectomy is expected to become a backup choice for patients with polycystic ovaries in the future.

Sleeve Gastrectomy Associated with Antral Lesion Resection and Roux-en-Y Antrojejunal Reconstruction

Obesity has been growing worldwide, reaching epidemic proportions. Bariatric surgery is the most effective and durable treatment for severe obesity and related diseases. Roux-en-Y Gastric Bypass (RYGB) and Sleeve Gastrectomy (SG) are the most frequently performed bariatric operations, with long-term good results, in terms of weight loss and comorbidities control. Gastroesophageal Reflux Disease (GERD) is commonly associated with obesity. In general, it precludes the indication of sleeve gastrectomy, since this technique has a refluxogenic potential, as shown in many studies. In such cases, RYGB is considered the best surgery, reaching good weight loss and gastroesophageal reflux disease control. The drawback of this technique is that it leaves the remnant stomach, the duodenum, and the proximal part of the jejunum inaccessible. Besides, RYGB makes transoral endoscopic access to the biliary tree impossible. For all these reasons, this bariatric technique is not indicated in cases of gastric polyposis, gastric dysplasia, or strong family history of cancer, among others. We report a case of a morbidly obese patient with intense GERD, for whom a RYGB was precluded due to her strong family history of cancer, even knowing that it would be the best choice for reflux disease control. Instead, SG was chosen, even knowing it could worsen the gastroesophageal reflux disease. The patient signed an informed consent, after being fully enlightened about the risks. During the surgery, a small subserosal whitish lesion was detected, near the pylorus, on the anterior wall of the antrum. Thinking in a Gastrointestinal Stromal Tumor (GIST), it was resected, with a 2 cm safety margin, leaving a 4 to 5 cm hole on the gastric wall. The decision to maintain the proposed sleeve gastrectomy was made, to avoid leaving a remnant stomach, in a patient with such a strong family history of cancer. In the area of the resected lesion, an intraoperative decision was made not to just close the big gastric hole, being afraid of causing some anatomic or functional disturbance in gastric emptying. Instead, we decided to use the gastric opening to construct a Roux-en-Y antrotrojejunal anastomosis, with a 50 cm alimentary limb and a 200 cm biliopancreatic limb. Accordingly, it was performed a sleeve gastrectomy, associated with an antrojejunostomy in a Roux-en-Y fashion. The patient had an uneventful postoperative course. In the second year, she achieved normal weight and good nutritional status, without gastroesophageal reflux symptoms complaints. Seriography study shows that most of the contrast material passes through the antrojejunal anastomosis, instead of the pylorus, while the duodenum is endoscopically patent. This case report shows an unexpected surgical finding that led to a tactic of adding a Roux-en-Y gastric bypass in the antrum, associated with a sleeve gastrectomy, a strategy that may be adopted in cases of morbidly obese patients with important GERD, for whom gastrointestinal exclusions are contraindicated. To confirm this hypothesis, controlled studies are needed.

Fibroblast growth factor 15,induced by elevated bile acids,mediates the improvement of hepatic glucose metabolism after sleeve gastrectomy

BACKGROUND Fibroblast growth factor(FGF)15/19,which is expressed in and secreted from the distal ileum,can regulate hepatic glucose metabolism in an endocrine manner.The levels of both bile acids(BAs)and FGF15/19 are elevated after bariatric surgery.However,it is unclear whether the increase in FGF15/19 is induced by BAs.Moreover,it remains to be understood whether FGF15/19 elevations contribute to improvements in hepatic glucose metabolism after bariatric surgery.AIM To investigate the mechanism of improvement of hepatic glucose metabolism by elevated BAs after sleeve gastrectomy(SG).METHODS By calculating and comparing the changes of body weight after SG with SHAM group,we examined the weight-loss effect of SG.The oral glucose tolerance test(OGTT)test and area under the curve of OGTT curves were used to assess the anti-diabetic effects of SG.By detecting the glycogen content,expression and activity of glycogen synthase as well as the glucose-6-phosphatase(G6Pase)and phosphoenolpyruvate carboxykinase(Pepck),we evaluated the hepatic glycogen content and gluconeogenesis activity.We examined the levels of total BA(TBA)together with the farnesoid X receptor(FXR)-agonistic BA subspecies in systemic serum and portal vein at week 12 post-surgery.Then the histological expression of ileal FXR and FGF15 and hepatic FGF receptor 4(FGFR4)with its corresponding signal pathways involved in glucose metabolism were detected.RESULTS After surgery,food intake and body weight gain of SG group was decreased compare with the SHAM group.The hepatic glycogen content and glycogen synthase activity was significantly stimulated after SG,while the expression of the key enzyme for hepatic gluconeogenesis:G6Pase and Pepck,were depressed.TBA levels in serum and portal vein were both elevated after SG,the FXR-agonistic BA subspecies:Chenodeoxycholic acid(CDCA),lithocholic acid(LCA)in serum and CDCA,DCA,LCA in portal vein were all higher in SG group than that in SHAM group.Consequently,the ileal expression of FXR and FGF15 were also advanced in SG group.Moreover,the hepatic expression of FGFR4 was stimulated in SG-operated rats.As a result,the activity of its corresponding pathway for glycogen synthesis:FGFR4-Ras-extracellular signal regulated kinase pathway was stimulated,while the corresponding pathway for hepatic gluconeogenesis:FGFR4-cAMP regulatory element-binding protein-peroxisome proliferator-activated receptorγcoactivator-1αpathway was suppressed.CONCLUSION Elevated BAs after SG induced FGF15 expression in distal ileum by activating their receptor FXR.Furthermore,the promoted FGF15 partly mediated the improving effects on hepatic glucose metabolism of SG.

State of art on the mechanisms of laparoscopic sleeve gastrectomy in treating type 2 diabetes mellitus

Obesity and type-2 diabetes mellitus(T2DM)are metabolic disorders.Obesity increases the risk of T2DM,and as obesity is becoming increasingly common,more individuals suffer from T2DM,which poses a considerable burden on health systems.Traditionally,pharmaceutical therapy together with lifestyle changes is used to treat obesity and T2DM to decrease the incidence of comorbidities and allcause mortality and to increase life expectancy.Bariatric surgery is increasingly replacing other forms of treatment of morbid obesity,especially in patients with refractory obesity,owing to its many benefits including good long-term outcomes and almost no weight regain.The bariatric surgery options have markedly changed recently,and laparoscopic sleeve gastrectomy(LSG)is gradually gaining popularity.LSG has become an effective and safe treatment for type-2 diabetes and morbid obesity,with a high cost-benefit ratio.Here,we review the mechanism associated with LSG treatment of T2DM,and we discuss clinical studies and animal experiments with regard to gastrointestinal hormones,gut microbiota,bile acids,and adipokines to clarify current treatment modalities for patients with obesity and T2DM.