Galactic Foreground Constraints on Primordial B-mode Detection for Ground-based Experiments

Contamination by polarized foregrounds is one of the biggest challenges for future polarized cosmic microwave background (CMB) surveys and the potential detection of primordial B-modes. Future experiments, such as Simons Observatory (SO) and CMB-S4, will aim at very deep observations in relatively small (f sky ∼ 0.1) areas of the sky. In this work, we investigate the forecasted performance, as a function of the survey field location on the sky, for regions over the full sky, balancing between polarized foreground avoidance and foreground component separation modeling needs. To do this, we simulate observations by an SO-like experiment and measure the error bar on the detection of the tensor-to-scalar ratio, σ(r), with a pipeline that includes a parametric component separation method, the Correlated Component Analysis, and the use of the Fisher information matrix. We forecast the performance over 192 survey areas covering the full sky and also for optimized low-foreground regions. We find that modeling the spectral energy distribution of foregrounds is the most important factor, and any mismatch will result in residuals and bias in the primordial B-modes. At these noise levels, σ(r) is not especially sensitive to the level of foreground contamination, provided the survey targets the least-contaminated regions of the sky close to the Galactic poles.

Extensive Abdominal Skin Necrosis Following Anterior Component Separation for a Large Ventral Hernia: A Case Report

Introduction: Hernia surgery is one of the most common operative procedures, performed in about 20 million cases per year all over the world, with ventral hernia accounting for about 30% of the cases. Although the introduction of the anterior component separation (ACS) method, popularized primarily by Oscar Ramirez, has greatly facilitated the closure of the largest abdominal wall defects, the 30-year experience in this technique has pointed to the risk of ischemic skin complications consequential to the major subcutaneous tissue dissection required. The aim of this case presentation of a patient who developed extensive necrosis of the abdominal wall skin following ACS procedure is to emphasize the importance of preserving rectus abdominis perforator blood vessels in order to preserve skin vitality.Case Presentation: We present a case of a 58-year-old female patient with a large recurrent ventral hernia. The hernial defect was closed by placing a large (30 × 25 cm) polypropylene mesh in the retro-rectus space using the Rives-Stoppa technique. To facilitate upper fascia closure ACS according to Ramirez was performed bilaterally. The rectus perforator vessels were not preserved. Recovery of the patient was complicated with the extensive abdominal skin necrosis which was successfully treated with negative pressure wound therapy.Discussion: Transection of the musculocutaneous perforators of the epigastric artery during ACS results with the compromised blood supply of the abdominal skin depending solely upon the intercostal arteries. Skin ischemia following ACS is a serious complication that can be presented with extensive necrosis associated with high morbidity and even mortality, while the treatment is long lasting, complex, and expensive. Considering the ever-increasing prevalence of large ventral hernias, ever greater popularity of the ACS technique, and the growing proportion of surgeons performing large ventral hernia operations independently, we think that the role of preserving perforated rectus vessels has not been emphasized enough. Therefore, the objective of this case study is to stimulate surgeons to preserve skin vascularity and promote it in their routine in order to avoid these severe postoperative complications.

Mitochondrial Transplantation Attenuates Cerebral Ischemia-Reperfusion Injury: Possible Involvement of Mitochondrial Component Separation

Background. Mitochondrial dysfunctions play a pivotal role in cerebral ischemia-reperfusion (I/R) injury. Although mitochondrial transplantation has been recently explored for the treatment of cerebral I/R injury, the underlying mechanisms and fate of transplanted mitochondria are still poorly understood. Methods. Mitochondrial morphology and function were assessed by fluorescent staining, electron microscopy, JC-1, PCR, mitochondrial stress testing, and metabolomics. Therapeutic effects of mitochondria were evaluated by cell viability, reactive oxygen species (ROS), and apoptosis levels in a cellular hypoxia-reoxygenation model. Rat middle cerebral artery occlusion model was applied to assess the mitochondrial therapy in vivo. Transcriptomics was performed to explore the underlying mechanisms. Mitochondrial fate tracking was implemented by a variety of fluorescent labeling methods. Results. Neuro-2a (N2a) cell-derived mitochondria had higher mitochondrial membrane potential, more active oxidative respiration capacity, and less mitochondrial DNA copy number. Exogenous mitochondrial transplantation increased cellular viability in an oxygen-dependent manner, decreased ROS and apoptosis levels, improved neurobehavioral deficits, and reduced infarct size. Transcriptomic data showed that the differential gene enrichment pathways are associated with metabolism, especially lipid metabolism. Mitochondrial tracking indicated specific parts of the exogenous mitochondria fused with the mitochondria of the host cell, and others were incorporated into lysosomes. This process occurred at the beginning of internalization and its efficiency is related to intercellular connection. Conclusions. Mitochondrial transplantation may attenuate cerebral I/R injury. The mechanism may be related to mitochondrial component separation, altering cellular metabolism, reducing ROS, and apoptosis in an oxygen-dependent manner. The way of isolated mitochondrial transfer into the cell may be related to intercellular connection.

A Comparison of Component Separation With Porcine Acellular Dermal Reinforcement to Bovine Acellular Dermal Matrix in the Repair of Significant Midline Ventral Hernia Defects

Background The optimal material for reinforcement of complex abdominal ventral hernia repair (VHR) remains controversial. Biologic prostheses such as porcine and bovine acellular dermal matrix (PADM/BADM) have shown favorable results, but few head-to-head comparisons between the two types exist. We sought to provide such a comparison. Methods We performed a retrospective cohort study comparing 40 consecutive patients who underwent open component separation (CS/VHR) with PADM reinforcement to 39 consecutive patients who underwent open CS/VHR with BADM reinforcement at our institution. Patient characteristics, outcomes, complications, reoperations, and hernia recurrences were obtained by chart review. Fisher’s exact and t-test analyses compared patient characteristics and outcomes between the 2 cohorts. Statistical significance was set as P < .05. Results Patient groups did not differ significantly in race (P=.36), age (P=.8), BMI (P=.34), sex (P=.09), steroid usage (p-1.00), COPD (P=.43), number of previous abdominal operations (P=.66), and duration of follow-up (P=.65). There were significantly more smokers in the PADM group (37.5% vs 12.8%, P=.01). Mean defect size was significantly greater in the PADM group (372.5 cm2 vs 292. cm2 in the BADM group, P=.001) as was the number of Ventral Hernia Working Group (VHWG) grade III/IV hernias (65.0% vs 38.4%, P=.02). Recurrence rates were lower in the BADM group, (12.5% vs 5.1%, P=.26), as was recurrence or complications requiring reoperation (17.5% vs 5.1%, P=.15). Postoperative wound events were also significantly lower in the BADM group (30.0% vs 2.6%, P=.001). Conclusions In our series, CS/BADM was associated with significantly fewer wound complications. Recurrences and complications requiring reoperation were also fewer, which trended toward but did not reach statistical significance, presumably due to the small sample size. These findings indicating superiority of BADM over PADM are potentially confounded by the higher percentage of smokers, the larger mean defect size, and the higher number of VHWG III/IV patients in the PADM group. Further prospective study of these findings is warranted.

O50 ALTERATIONS IN THE ABDOMINAL WALL MUSCULATURE AFTER ENDOSCOPIC ANTERIOR AND OPEN POSTERIOR COMPONENT SEPARATION

Aim Effects of component separation (CS) on abdominal wall musculature have only been investigated in smaller case series. The study aimed to compare abdominal wall alterations following endoscopic anterior component separation (EACS) or transverse abdominis release (TAR). Material and Methods Computed tomography scans were evaluated in patients who underwent open ventral hernia repair with TAR or EACS. Lateral abdominal wall muscle thickness and displacement were compared with preoperative images after bilateral CS and the undivided side postoperatively after unilateral CS. Results In total, 105 patients were included. The mean defect width was 12.2 cm. Fifty-five (52%) and 15 (14%) underwent bilateral and unilateral EACS, respectively. Five (5%) and 14 (13%) underwent bilateral and unilateral TAR, respectively. Sixteen (15%) underwent unilateral EACS and contralateral TAR. Complete fascial closure was achieved in 103 (98%) patients. The external oblique and transverse abdominis muscles were significantly laterally displaced with a mean of 2.74 cm (95% CI 2.29-3.19 cm) and 0.82 cm (0.07-1.57 cm) after EACS and TAR, respectively. The combined thickness of the lateral muscles was significantly decreased after EACS (mean decrease 10.5% [5.8-15.6%]) and insignificantly decreased after TAR (mean decrease 2.6% [-4.8-9.5%]), mean reduction difference EACS versus TAR 0.22 cm (-0.01-0.46 cm). One (1%) patient developed an iatrogenic linea semilunaris hernia after EACS. The recurrence rate was 19% after mean 1.7 years follow-up. Conclusions The divided muscle was significantly more laterally displaced after EACS compared with TAR. The thickness of the lateral muscles was slightly decreased after EACS and unchanged after TAR.