CMS Silicon Pixel Detector Callibration

The Compact Muon Solenoid (CMS) pixel group at Cornell University is building a silicon pixel detector test station that will model the revolutionary detection and data acquisition system designed for the CMS experiment at the Large Hadron Collider (LHC) at CERN. When fully implemented at the LHC, the detector\u27s sixty-six million pixels will be able to track and time passing charged particles that result from proton-proton collisions happening every twenty-five nanoseconds. With parts of the Cornell test station apparatus already functional, we have begun to understand and optimize the detector\u27s programmable settings that tune its performance. The success of these optimizations has been quantified by performing various calibrations also being developed here, that will also be used at the LHC to ensure that the pixel detector is working properly and taking the most accurate data possible

Sacral nerve stimulation in patients with ileal pouch-anal anastomosis

Purpose: Functional results after proctocolectomy and ileal pouch-anal anastomosis (IPAA) are generally good. However, some patients suffer from high stool frequency or fecal incontinence. Sacral nerve stimulation (SNS) may represent a therapeutic alternative in these patients, but little is known about indication and results. The aim of this study was to evaluate incontinence after IPAA and demonstrate SNS feasibility in these patients. Methods: This retrospective study includes patients who received a SNS between 1993 and 2020 for increased stool frequency or fecal incontinence after proctocolectomy with IPAA for ulcerative colitis. Proctocolectomy was performed in a two- or three-step approach with ileostomy closure as the last step. Demographic, follow-up data and functional results were obtained from the hospital database. Results: SNS was performed in 23 patients. Median follow-up time after SNS was 6.5 years (min. 4.2-max. 8.8). Two patients were lost to follow-up. The median time from ileostomy closure to SNS implantation was 6 years (min. 0.5-max. 14.5). Continence after SNS improved in 16 patients (69%) with a median St. Marks score for anal incontinence of 19 (min. 4-max. 22) before SNS compared to 4 (0-10) after SNS placement (p = 0.012). In seven patients, SNS therapy was not successful. Conclusion: SNS implantation improves symptoms in over two-thirds of patients suffering from high stool frequency or fecal incontinence after proctocolectomy with IPAA. Awareness of the beneficial effects of SNS should be increased in physicians involved in the management of these patients

Inflammation of the rectal remnant endangers the outcome of ileal pouch-anal anastomosis: a case–control study

Background: Inflammation of the rectal remnant may affect the postoperative outcome of ileal pouch-anal anastomosis (IPAA) in patients with ulcerative colitis (UC). We aimed to determine the extent of inflammation in the anastomotic area during IPAA and to investigate the impact of proctitis on postoperative complications and long-term outcomes. Methods: Three hundred thirty-four UC patients with primary IPAA were included in this retrospective case-control study. The histopathologic degree of inflammation in the anastomotic area was graded into three stages of no proctitis ("NOP"), mild to medium proctitis ("MIP"), and severe proctitis ("SEP"). Preoperative risk factors, 30-day morbidity, and follow-up data were assessed. Kaplan-Meier analysis was performed in the event of pouch failure. Results: The prevalence of proctitis was high (MIP 40.4%, and SEP 42.8%). During follow-up, the incidence of complications was highest among SEP: resulting in re-intervention (n = 40; 28.2%, p = 0.017), pouchitis (n = 36; 25.2%, p < 0.01), and pouch failure (n = 32; 22.4%, p = 0.032). The time interval to pouch failure was 5.0 (4.0-6.9) years among NOP, and 1.2 (0.5-2.3) years in SEP (p = 0.036). ASA 3, pouchitis, and pouch fistula were independent risk factors for pouch failure. Conclusion: Proctitis at the time of IPAA is common. A high degree of inflammation is associated with poor long-term outcomes, an effect that declines over time. In addition, a higher degree of proctitis leads to earlier pouch failure

FPGA-accelerated machine learning inference as a service for particle physics computing

New heterogeneous computing paradigms on dedicated hardware with increased parallelization, such as Field Programmable Gate Arrays (FPGAs), offer exciting solutions with large potential gains. The growing applications of machine learning algorithms in particle physics for simulation, reconstruction, and analysis are naturally deployed on such platforms. We demonstrate that the acceleration of machine learning inference as a web service represents a heterogeneous computing solution for particle physics experiments that potentially requires minimal modification to the current computing model. As examples, we retrain the ResNet-50 convolutional neural network to demonstrate state-of-the-art performance for top quark jet tagging at the LHC and apply a ResNet-50 model with transfer learning for neutrino event classification. Using Project Brainwave by Microsoft to accelerate the ResNet-50 image classification model, we achieve average inference times of 60 (10) milliseconds with our experimental physics software framework using Brainwave as a cloud (edge or on-premises) service, representing an improvement by a factor of approximately 30 (175) in model inference latency over traditional CPU inference in current experimental hardware. A single FPGA service accessed by many CPUs achieves a throughput of 600--700 inferences per second using an image batch of one, comparable to large batch-size GPU throughput and significantly better than small batch-size GPU throughput. Deployed as an edge or cloud service for the particle physics computing model, coprocessor accelerators can have a higher duty cycle and are potentially much more cost-effective.Comment: 16 pages, 14 figures, 2 table

Operative outcome of hernia repair with synthetic mesh in immunocompromised patients

Background: The safety of synthetic mesh in elective hernia repair in the setting of immunosuppression lacks national and international consensus. The aim of our analysis was to explore the effects of immunosuppression on the rates of wound complications. Methods: Comparative analysis of immunocompetent and immunocompromised patients with elective mesh repair of inguinal, femoral, primary ventral, incisional or parastomal hernia between January 2001 and December 2013. Immunosuppression included glucocorticoids, biologicals, chemotherapy and chemoradiotherapy. Primary outcome parameter was mesh infection rate. Follow-up questionnaires were completed in written form or by telephone interview. Results: Questionnaire response rate was 59.5% (n= 194) with a median follow-up of 33 (interquartile range: 28-41) months. There were no differences between immunocompromised (n= 40, 20.6%) and immunocompetent patients (n= 154, 79.4%) based on hernia and patient characteristics. Immunosuppression was not associated with the rates of mesh infection (P= 1.000), surgical site infection (SSI,P= 0.330) or re-operation for SSI (P= 0.365), but with higher rates (P= 0.007) and larger odds for hernia recurrence (odds ratio 3.264, 95% confidence interval 1.304-8.172;P= 0.012). Mesh infection also increased the odds for hernia recurrence (odds ratio 11.625; 95% confidence interval 1.754-77.057;P= 0.011). Only in the subset of ventral/incisional hernias, immunocompromised (n= 8, 40%) patients had higher recurrence rates than immunocompetent patients (n= 5, 11.6%;P= 0.017). Patients with SSI reported more frequently moderate to severe dysesthesia at the surgical site (P= 0.013) and would less frequently re-consent to surgery (P= 0.006). Conclusion Immunosuppression does not increase the rate of wound infections after elective hernia repair with synthetic mesh. However, immunosuppression and mesh infection are risk factors for hernia recurrence

Risk factors for upper and lower type prolonged postoperative ileus following surgery for Crohn’s disease

Purpose: Prolonged postoperative ileus (PPOI) is common after bowel resections, especially in Crohn's disease (CD). The pathophysiology of PPOI is not fully understood. PPOI could affect only the upper or lower gastrointestinal (GI) tract. The aim of this study was to assess risk factors for diverse types of PPOI, particularly to differentiate PPOI of upper and lower GI tract. Methods: A retrospective analysis of 163 patients with CD undergoing ileocecal resection from 2015 to 2020 in a single center was performed. PPOI of the upper GI tract was predefined as the presence of vomiting or use of nasogastric tube longer than the third postoperative day. Lower PPOI was predefined as the absence of defecation for more than three days. Independent risk factors were identified by multivariable logistic regression analysis. Results: Overall incidence of PPOI was 42.7%. PPOI of the upper GI tract was observed in 30.7% and lower PPOI in 20.9% of patients. Independent risk factors for upper PPOI included older age, surgery by a resident surgeon, hand-sewn anastomosis, prolonged opioid analgesia, and reoperation, while for lower PPOI included BMI <= 25 kg/m(2), preoperative anemia, and absence of ileostomy. Conclusion: This study identified different risk factors for upper and lower PPOI after ileocecal resection in patients with CD. A differentiated upper/lower type approach should be considered in future research and clinical practice. High-risk patients for each type of PPOI should be closely monitored, and modifiable risk factors, such as preoperative anemia and opioids, should be avoided if possible

Validation of the German Classification of Diverticular Disease (VADIS)—a prospective bicentric observational study

Purpose: The German Classification of Diverticular Disease was introduced a few years ago. The aim of this study was to determine whether Classification of Diverticular Disease enables an exact stratification of different types of diverticular disease in terms of course and treatment. Methods: This was a prospective, bicentric observational trial. Patients aged ≥ 18 years with diverticular disease were prospectively included. The primary endpoint was the rate of recurrence within 2 year follow-up. Secondary outcome measures were Gastrointestinal Quality of Life Index, Quality of life measured by SF-36, frequency of gastrointestinal complaints, and postoperative complications. Results: A total of 172 patients were included. After conservative management, 40% of patients required surgery for recurrence in type 1b vs. 80% in type 2a/b (p = 0.04). Sixty percent of patients with type 2a (micro-abscess) were in need of surgery for recurrence vs. 100% of patients with type 2b (macro-abscess) (p = 0.11). Patients with type 2a reached 123 ± 15 points in the Gastrointestinal Quality of Life Index compared with 111 ± 14 in type 2b (p = 0.05) and higher scores in the “Mental Component Summary” scale of SF-36 (52 ± 10 vs. 43 ± 13; p = 0.04). Patients with recurrent diverticulitis without complications (type 3b) had less often painful constipation (30% vs. 73%; p = 0.006) when they were operated compared with conservative treatment. Conclusion: Differentiation into type 2a and 2b based on abscess size seems reasonable as patients with type 2b required surgery while patients with type 2a may be treated conservatively. Sigmoid colectomy in patients with type 3b seems to have gastrointestinal complaints during long-term follow-up. Trial registration: https://www.drks.de ID: DRKS0000557

Impact of myopenia and myosteatosis on postoperative outcome and recurrence in Crohn’s disease

PURPOSE: Myopenia and myosteatosis have been proposed to be prognostic factors of surgical outcomes for various diseases, but their exact role in Crohn’s disease (CD) is unknown. The aim of this study is to evaluate their impact on anastomotic leakage, CD recurrence, and postoperative complications after ileocecal resection in patients with CD. METHODS: A retrospective analysis of CD patients undergoing ileocecal resection at our tertiary referral center was performed. To assess myopenia, skeletal muscle index (skeletal muscle area normalized for body height) was measured using an established image analysis method at third lumbar vertebra level on MRI cross-sectional images. Muscle signal intensity was measured to assess myosteatosis index. RESULTS: A total of 347 patients were retrospectively analyzed. An adequate abdominal MRI scan within 12 months prior to surgery was available for 223 patients with median follow-up time of 48.8 months (IQR: 20.0–82.9). Anastomotic leakage rate was not associated with myopenia (SMI: p = 0.363) or myosteatosis index (p = 0.821). Patients with Crohn’s recurrence had a significantly lower SMI (p = 0.047) in univariable analysis, but SMI was not an independent factor for recurrent anastomotic stenosis in multivariable analysis (OR 0.951, 95% CI 0.840–1.078; p = 0.434). Postoperative complications were not associated with myopenia or myosteatosis. CONCLUSION: Based on the largest cohort of its kind with a long follow-up time, we could provide some data that MRI parameters for myopenia and myosteatosis may not be reliable predictors of postoperative outcome or recurrence in patients with Crohn’s disease undergoing ileocecal resection

The impact of surgical site infection—a cost analysis

Purpose: Surgical site infection (SSI) occurs in up to 25% of patients after elective laparotomy. We aimed to determine the effect of SSI on healthcare costs and patients' quality of life. Methods: In this post hoc analysis based on the RECIPE trial, we studied a 30-day postoperative outcome of SSI in a single-center, prospective randomized controlled trial comparing subcutaneous wound irrigation with 0.04% polyhexanide to 0.9% saline after elective laparotomy. Total medical costs were analyzed accurately per patient with the tool of our corporate controlling team which is based on diagnosis-related groups in Germany. Results: Between November 2015 and May 2018, 456 patients were recruited. The overall rate of SSI was 28.2%. Overall costs of inpatient treatment were higher in the group with SSI: median 16.685 euro; 19.703 USD (IQR 21.638 euro; 25.552 USD) vs. median 11.235 euro; 13.276 USD (IQR 11.564 euro; 13.656 USD); p < 0.001. There was a difference in surgery costs (median 6.664 euro; 7.870 USD with SSI vs. median 5.040 euro; 5.952 USD without SSI; p = 0.001) and costs on the surgical ward (median 8.404 euro; 9.924 USD with SSI vs. median 4.690 euro; 5.538 USD without SSI; p < 0.001). Patients with SSI were less satisfied with the cosmetic result (4.3% vs. 16.2%; p < 0.001). Overall costs for patients who were irrigated with saline were median 12.056 euro; 14.237 USD vs. median 12.793 euro; 15.107 USD in the polyhexanide group (p = 0.52). Conclusion: SSI after elective laparotomy increased hospital costs substantially. This is an additional reason why the prevention of SSI is important. Overall costs for intraoperative wound irrigation with saline were comparable with polyhexanide