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Involute gears have traditionally been the preferred choice for gear transmission systems due to their simplicity and interchangeability. However, there are applications where they do not provide the most durable and efficient solution. While the cost of implementing optimized non-involute gears in most applications often outweighs their comparative advantages, the advent of additive manufacturing has opened up possibilities for designers to explore alternative gear tooth profiles. This is particularly relevant in the realm of plastic gears, where optimized non-involute gears produced through 3D printing can address their primary drawbacks, such as surface durability and wear resistance. In this study, a comprehensive free-form optimization process was conducted to determine the optimal tooth profile that minimizes wear on 3D printed spur gears during operation. The tooth flank geometry was represented using a 4th order B-spline curve, and a genetic algorithm was employed to determine the optimum positions of the control points aiming to minimize wear depth across the tooth flanks. The spur gears were manufactured using Fused Deposition Modeling (FDM) with PLA material. The parameters of the additive manufacturing process were experimentally fine-tuned to achieve the best possible accuracy. To evaluate the performance of the optimized free-form gears, two case studies were implemented, demonstrating that the optimized gears achieved a remarkable reduction of average wear depth by more than 50% and a reduction of maximum wear depth by more than 69% compared to standard involute gears. To further validate the effectiveness of the optimization method, experiments were carried out using an FZG test rig. The profiles of the tooth flanks were measured on a Coordinate Measuring Machine (CMM) before and after the experiments to compare the wear depth against the standard involute gears. The results revealed a significant improvement in the wear resistance of the tooth flanks, with a reduction of wear depth of 44.1%.

Abstract Introduction We report the case of a patient with a benign multicystic peritoneal mesothelioma and describe its appearance on computed tomography scans and ultrasonography, in correlation with gross clinical and pathological findings. Case presentation A 72-year-old Caucasian woman presented to our emergency department with acute abdomen signs and symptoms. A clinical examination revealed a painful palpable mass in her left abdomen. Abdominal ultrasonography and computed tomography demonstrated the presence of a large cystic mass in her left upper abdomen, adjacent to her left hemidiaphragm. The lower border of the mass extended to the upper margin of her pelvis. A complete resection of the lesion was performed. Pathological analysis showed a benign multicystic peritoneal mesothelioma. Conclusions Benign multicystic peritoneal mesothelioma is a rare lesion with a non-specific appearance on imaging. Its diagnosis always requires pathological analysis.

Abstract Background Although local excision (ampullectomy) was first described by Halsted in 1899, its adequacy as an alternative surgical treatment for the ampullary tumors is still a matter of debate. The aim of this study was to evaluate the results of ampullectomy as a curative treatment for benign and malignant tumors arising from the ampulla, in a 14-year single-institution experience. Methods From 1990 to 2004, a total of 20 patients of adenocarcinoma (12) or adenoma (8) of the ampulla of Vater underwent local excision. Clinical data were collected and morbidity, mortality, as well as long-term survival were evaluated. The usefulness of several pre or intraoperative diagnostic methods was also recorded. Median follow-up was 85 (range 6–180) months. Results The combination of endoscopic preoperative biopsies and intraoperative frozen section examination adequately diagnosed ampullary tumors in all cases. The postoperative morbidity and mortality were 0%, whereas the 3 and 5-year survival rates for the patients with adenocarcinoma was 75 % and 33.3 % respectively. All the patients with adenoma are still alive without any sign of recurrence. Conclusion In our series, local excision was a safe option, associated with satisfactory long-term survival rates in patients with benign lesions and in those with small(

Abstract Background Metastases from hepatocellular carcinoma (HCC) can be found in the lung and adrenal gland. We report case of a patient who presented with adrenal metastasis as the first clinical manifestation of HCC. Case presentation A patient was referred for surgical treatment for a tumor in retro-peritoneal space. The computerized tomography (CT) scan revealed a mass originating from the left adrenal gland. The patient underwent left adrenalectomy and the exploration of abdominal cavity did not reveal any other palpable lesions. Histologically, the resected lesion was a poorly differentiated metastatic tumor from HCC. Seven months later patient was readmitted complaining of cachexia, icterus, and significant weight loss. CT scan revealed hyperdense lesions of the liver Conclusion HCC may have atypical presentations like in present case. Fine needle aspiration/tru-cut® biopsy might be useful in the investigation of an accidentally discovered adrenal mass regardless of the size and can lead to the detection of a primary tumor.

BACKGROUND Solitary parathyroid adenomas are the leading cause of primary hyperparathyroidism in 0% to 85% of cases. Diagnosis of parathyroid adenoma is based on typical clinical presentation of hypercalcemia, biochemical profile, and modern imaging studies. The purpose of this article is to present the diagnostic and therapeutic approach used for a 73-year-old female patient with a giant parathyroid adenoma measuring 5×2.5×2.5 cm and weighing 30 grams. CASE REPORT A 73-year-old female was referred to the outpatient clinic of our Surgical Department with the diagnosis of primary hyperparathyroidism. The patient suffered from typical symptoms of hypercalcemia such as weakness, bone disease, and recurrent nephrolithiasis; she had a painless cervical mass for 5 months. Primary hyperparathyroidism was confirmed based on the patient's biochemical profile, which showed increased levels of serum calcium and parathyroid hormone. SestaMIBI scintigraphy with 99mTechnetium and cervical ultrasonography revealed a large nodule at the inferior pole of the right lobe of the thyroid gland. Intraoperatively, a giant parathyroid adenoma was found and excised. Additionally, levels of intact parathyroid hormone (IOiPTH) were determined intraoperatively and a 95% reduction was found, 20 minutes after the removal of the adenoma. CONCLUSIONS This is an extremely rare case of a giant solitary parathyroid adenoma. Diagnosis of a giant hyperfunctioning solitary parathyroid adenomas was based on clinical presentation, biochemical profile, and imaging studies. Selective treatment was based on surgical excision combined with IOiPTH levels measurement.

Introduction: Intestinal wound healing is an essential process for surgical reconstruction of the digestive tract. The purpose of this study is to evaluate the effect of perioperative administration of glutamine and synbiotics on the biological behavior of intestinal mucosal barrier and the healing of colonic anastomosis in rats., Material and Methods: 80 Wistar rats were divided in five groups. A: Control. B: Mechanical bowel preparation and antibiotics.C: Glutamine. D: Synbiotics. E: Glutamine and synbiotics. The animals were sacrificed on 3rd and 7th postoperative day., Results: Zero mortality and no septic complications were noted. On 3rd postoperative days, a significant weight loss was observed in all groups in comparison with the preoperative weights, but on the 7th day in groups C and E, in contrast with the other groups, weight loss was not significant. On the 3rd postoperative day, neoangiogenesis, inflammatory infiltration and fibroblast activity were significantly enhanced in group E compared to control. On the 7th postoperative day in group E fibroblast activity was significantly enhanced and inflammatory infiltration was significantly limited compared to control. The bursting pressures as well as the hydroxyproline tissue content were significantly higher in the group E on 3rd and 7th postoperative days. The percentage of positive mesenteric lymph node cultures were significantly limited in group E compared to control., Conclusions: The administration of synbiotics in conjunction with glutamine resulted in increasing the mechanical strength of the anastomosis, thus increasing the bursting pressure and decreasing or effacing of anastomotic dehiscence and limiting bacterial translocation.

Introduction: We report the case of a patient with a benign multicystic peritoneal mesothelioma and describe its appearance on computed tomography scans and ultrasonography, in correlation with gross clinical and pathological findings., Case Presentation: A 72-year-old Caucasian woman presented to our emergency department with acute abdomen signs and symptoms. A clinical examination revealed a painful palpable mass in her left abdomen. Abdominal ultrasonography and computed tomography demonstrated the presence of a large cystic mass in her left upper abdomen, adjacent to her left hemidiaphragm. The lower border of the mass extended to the upper margin of her pelvis. A complete resection of the lesion was performed. Pathological analysis showed a benign multicystic peritoneal mesothelioma., Conclusions: Benign multicystic peritoneal mesothelioma is a rare lesion with a non-specific appearance on imaging. Its diagnosis always requires pathological analysis.

Background: A rare case of Mirizzi syndrome with atypical presentation is reported., Case Report: An 81-year-old woman with a known history of cholelithiasis presented with epigastric discomfort and indigestion. Imaging investigations revealed Mirizzi syndrome, while a cholecystobiliary fistula at the junction of the hepatic ducts was recognized intraoperatively and treated successfully with cholecystectomy and Roux-en-Y hepaticojejunostomy. During two years' follow-up the patient remains free of biliary symptoms., Conclusions: Diagnosis of Mirizzi syndrome requires a high degree of clinical suspicion, especially in cases without obstructive jaundice. A fistula at the level of the confluence of the hepatic ducts is a rare topographic variant of the syndrome that may need a totally different surgical approach.

Background: The aim of this retrospective study was to evaluate the outcome of laparoscopic cholecystectomies (LCs) performed in our Academic Surgical Unit, and the impact of our policy not to perform intraoperative cholangiograms (IOCs) on the incidence of bile duct injuries (BDIs)., Materials and Methods: Data was collected for the time period from 1992 (when the laparoscopic procedure was first introduced in our Unit) until 2005. During this time, 1851 patients underwent an LC. Patients with a history of jaundice, ultasonographic bile duct dilatation, bile duct stones, or deranged liver function tests were referred initially for an endoscopic retrograde cholangiopancreatography procedure. An IOC was not performed on any patient., Results: The conversion rate was 23.9% among the patients with acute cholecystitis and 1.6% among the patients with a noninflamed gallbladder. This difference was statistically significant. The morbidity reached 1.1%, as minor or major complications were present in 22 of 1851 patients. Complications consisted of BDI in 7 patients (0.37%). Six patients presented with minor BDI. Two of the BDIs occurred among the group of patients with acute cholecystitis, whereas the remaining 5 occurred in the group of patients with a noninflamed gallbladder. This distribution was not statistically significant., Conclusions: The low BDI rate in our series allowed us to recommend an LC procedure without an IOC. Performing a cholangiogram either routinely or selectively is not wrong. However, adherence to a meticulous hemostatic technique, thorough knowledge of the anatomy, and a low threshold for conversion may also enable satisfactory results to be achieved.

The aim of this experimental study was to investigate the contribution of insulin-like growth factor I (IGF)-I in the colonic healing process when injected intraperitoneally after colon resection. Forty male Wistar rats were used. Rats in the control group were injected with 3 mL of a solution of 0.9% NaCl intraperitoneally after the operation and on postoperative day 2, 4, and 6. Rats in the IGF-I group received recombinant human IGF-I in a dose of 2 mg/kg body weight intraperitoneally, immediately after the colonic anastomosis was performed and on postoperative day 2, 4, and 6. All rats were killed on postoperative day 7. The hydroxyproline tissue content was significantly higher in the IGF-1 group than in the control group. The bursting pressures were also significantly higher in IGF-1 group than in the control group. The weight change between the groups differed significantly; in the control group the average weight decreased about 5% postoperatively, while in the IGF-1 group the average weight increased about 6%. The average inflammatory cell infiltration score was significantly higher in the control group. Neoagiogenesis did not differ significantly between the two groups. The fibroblast activity differed significantly between the two groups, as the control group had significantly less fibroblasts compared to the IGF-1 group. In conclusion, IGF-I when given intraperitoneally stimulates the healing of colonic anastomoses in the rats. Further studies are required in order to determine whether this effect is dose related.

Background: Although local excision (ampullectomy) was first described by Halsted in 1899, its adequacy as an alternative surgical treatment for the ampullary tumors is still a matter of debate. The aim of this study was to evaluate the results of ampullectomy as a curative treatment for benign and malignant tumors arising from the ampulla, in a 14-year single-institution experience., Methods: From 1990 to 2004, a total of 20 patients of adenocarcinoma (12) or adenoma (8) of the ampulla of Vater underwent local excision. Clinical data were collected and morbidity, mortality, as well as long-term survival were evaluated. The usefulness of several pre or intraoperative diagnostic methods was also recorded. Median follow-up was 85 (range 6-180) months., Results: The combination of endoscopic preoperative biopsies and intraoperative frozen section examination adequately diagnosed ampullary tumors in all cases. The postoperative morbidity and mortality were 0%, whereas the 3 and 5-year survival rates for the patients with adenocarcinoma was 75 % and 33.3 % respectively. All the patients with adenoma are still alive without any sign of recurrence., Conclusion: In our series, local excision was a safe option, associated with satisfactory long-term survival rates in patients with benign lesions and in those with small(<2 cm), pT1, well differentiated ampullary tumours without nodal involvement.

Background: Metastases from hepatocellular carcinoma (HCC) can be found in the lung and adrenal gland. We report case of a patient who presented with adrenal metastasis as the first clinical manifestation of HCC., Case Presentation: A patient was referred for surgical treatment for a tumor in retro-peritoneal space. The computerized tomography (CT) scan revealed a mass originating from the left adrenal gland. The patient underwent left adrenalectomy and the exploration of abdominal cavity did not reveal any other palpable lesions. Histologically, the resected lesion was a poorly differentiated metastatic tumor from HCC. Seven months later patient was readmitted complaining of cachexia, icterus, and significant weight loss. CT scan revealed hyperdense lesions of the liver., Conclusion: HCC may have atypical presentations like in present case. Fine needle aspiration/tru-cut biopsy might be useful in the investigation of an accidentally discovered adrenal mass regardless of the size and can lead to the detection of a primary tumor.