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A fully integrated 0.18 [micro]m DC-DC buck converter using a low-swing 'stacked driver' configuration is reported in this paper. A high switching frequency of 660 MHz reduces filter components to fit on chip, but this suffers from high switching losses. These losses are reduced using: 1) low-swing drivers; 2) supply stacking; and 3) introducing a charge transfer path to deliver excess charge from the positive metal-oxide semiconductor drive chain to the load, thereby recycling the charge. The working prototype circuit converts 2.2 to 0.75-1.0 V at 40-55 mA. Design and simulation of an improved circuit is also included that further improves the efficiency by enhancing the charge recycling path, providing automated zero voltage switching (ZVS) operation, and synchronizing the half-swing gating signals. Index Terms--Charge recycling, integrated output filter, low-power stacked driver, subgigahertz switching, switch mode DC-DC converter.

Aim: The current study aimed to evaluate EGD findings effects on laparoscopic Roux-en-Y gastric bypass (RYGB) plan and time in areas with a high prevalence of Helicobacter pylori infection. Background: Esophagogastroduodenoscopy (EGD) and Helicobacter pylori testing are routine parts of preoperative assessment of bariatric surgery at many centers Methods: This was a cross-sectional study of all patients underwent EGD and histopathological examination before laparoscopic RYGB in three gastroenterology centers in Iran between January 2018 and December 2020. Results In total, 637 patients (52.4% female) were enrolled, of which 46.8% had no abnormal mucosal appearance. In 1.7%, surgery was canceled (gastric adenocarcinoma, gastric intestinal metaplasia, GIST, and esophageal varices). The prevalence of H. pylori was 61.5%, and there was no statistical difference between groups of normal and abnormal EGD; however, surgery was postponed after H. pylori eradication in both groups. Overall, 44.4% of patients with esophagitis (any grade), peptic ulcer disease, erosive and non-erosive gastritis/duodenitis, and short segment Barret's esophagus needed medical management. Small- or medium-sized sliding hiatal hernias were seen in 18.7% of patients with no effect on surgery. Moreover, 88.8% of patients with normal mucosal appearance were asymptomatic, but 92.6% in the group with abnormal EGD were symptomatic (p=0.01). Changes in surgical plan and time occurred in 63.6%, but after eliminating H. pylori eradication, it was 15.4%. Conclusion: Considering gastric cancer and the high prevalence of H. pylori in Iran, using EGD and histopathological examination as an investigation in the preoperative assessment would have a significant impact on patients undergoing RYGB surgery. [ABSTRACT FROM AUTHOR]

Aim: The current study aimed to investigate the risk factors, endoscopic findings, and treatments of upper gastrointestinal bezoars. Background: Bezoars are compact masses formed by the accumulation of dietary fiber, undigested food, hair, or medications. The majority of bezoars are asymptomatic, but they may cause serious symptoms or even life-threatening events such as bleeding, obstruction, or perforation Methods: This retrospective study was conducted in three gastroenterology clinics between January 2016 and December 2019. Bezoars were detected in 109 of 15,830 endoscopy records (0.68%). Results A total of 103 patients (52.4% male) were enrolled in this study. Mean patient age was 60.5±11.3 years. The most frequent risk factors were history of gastric surgery (25.2%), diabetes mellitus (21.3%), hypothyroidism (15.5%), trichophagia (5.8%), and anxiety disorders (2.9%), respectively. The most common endoscopic findings were peptic ulcers (34.9%), erosive gastritis/duodenitis (12.6%), and reflux esophagitis (10.6%). While bezoars were most commonly observed in the stomach (84.4%), the majority of them were phytobezoars (92.2%). The mean number of endoscopic interventions for each patient was 1.5 (range, 1-4). Endoscopy was successful in removing bezoars in 85.4%. Conclusion: The synergistic effect of multiple factors for a long time, such as gastrointestinal surgery, diabetes mellitus or psychiatric disorders, may lead to bezoar formation. These risk factors should be avoided or treated in order to prevent bezoar formation and subsequent life-threatening complications. [ABSTRACT FROM AUTHOR]

Introduction: Gastrointestinal complaints are common in patients with kidney failure. The aim of this study was to investigate the effect of creatinine clearance on Helicobacter pylori (HP) eradication rate in patients with peptic ulcer disease.Materials and Methods: In this clinical trial, 132 patients with a range of kidney function (normal to end-stage renal disease) and peptic ulcer disease with HP infection were enrolled and divided into 5 groups by their creatinine clearance. For all patients, a 14-day standard regimen of triple therapy for peptic ulcer was started with omeprazole, 20 mg; clarithromycin, 500 mg; and amoxicillin, 1 g; twice per day. After 6 weeks, HP eradication rate were evaluated and compared between the groups with urea breath test.Results: The mean age of the participants was 44.84 ± 12.20 years and 68 (51.5%) were women. The five groups were not significantly different in terms of age, sex distribution, or body mass index. The results of urea breath test at 6 weeks were positive in 23 patients (17.4%). There was no significant difference in HP eradication rate (negative urea breath test) between the five groups.Conclusions: This study showed no association between the success rate of eradication of HP infection and kidney function. [ABSTRACT FROM AUTHOR]