Insights into the Si─H Bonding Configuration at the Amorphous/Crystalline Silicon Interface of Silicon Heterojunction Solar Cells by Raman and FTIR Spectroscopy.

In silicon heterojunction solar cell technology, thin layers of hydrogenated amorphous silicon (a-Si:H) are applied as passivating contacts to the crystalline silicon (c-Si) wafer. Thus, the properties of the a-Si:H is crucial for the performance of the solar cells. One important property of a-Si:H is its microstructure which can be characterized by the microstructure parameter R based on Si─H bond stretching vibrations. A common method to determine R is Fourier transform infrared (FTIR) absorption measurement which, however, is difficult to perform on solar cells for various reasons like the use of textured Si wafers and the presence of conducting oxide contact layers. Here, it is demonstrated that Raman spectroscopy is suitable to determine the microstructure of bulk a-Si:H layers of 10 nm or less on textured c-Si underneath indium tin oxide as conducting oxide. A detailed comparison of FTIR and Raman spectra is performed and significant differences in the microstructure parameter are obtained by both methods with decreasing a-Si:H film thickness.

Choice of Polymer, but Not Mesh Structure Variation, Reduces the Risk of Bacterial Infection with Staphylococcus aureus In Vivo.

BACKGROUND: Synthetic mesh material is of great importance for surgical incisional hernia repair. The physical and biochemical characteristics of the mesh influence mechanical stability and the foreign body tissue reaction. The influence on bacterial infections, however, remains ill-defined. The aim of the present study was to evaluate the influence of a modified mesh structure with variation in filament linking on the occurrence of bacterial infection that is indicated by the occurrence of CD68+, CD4+, and CD8+ cells in two different materials. METHODS: A total of 56 male Sprague Dawley rats received a surgical mesh implant in a subcutaneous abdominal position. The mesh of two different polymers (polypropylene (PP) and polyvinylidenfluoride (PVDF)) and two different structures (standard structure and bold structure with higher filament linking) were compared. During the implantation, the meshes were infected with Staphylococcus (S.) aureus. After 7 and 21 days, meshes were explanted, and the early and late tissue responses to infection were histologically evaluated. RESULTS: Overall, the inflammatory tissue response was higher at 7 days when compared to 21 days. At 7 days, PP meshes of the standard structure (PP-S) showed the strongest inflammatory tissue response in comparison to all the other groups. At 21 days, no statistically significant difference between different meshes was detected. CD8+ cytotoxic T cells showed a significant difference at 21 days but not at 7 days. PP meshes of both structures showed a higher infiltration of CD8+ T cells than PVDF meshes. CD4+ T helper cells differed at 7 days but not at 21 days, and PVDF meshes in a bold structure showed the highest CD4+ T cell count. The number of CD68+ macrophages was also significantly higher in PP meshes in a standard structure when compared to PVDF meshes at 21 days. CONCLUSION: The inflammatory tissue response to S. aureus infection appears to be highest during the early period after mesh implantation. PP meshes showed a higher inflammatory response than PVDF meshes. The mesh material appears to be more important for the risk of infection than the variation in filament linking.

Successful Transplantation of a Liver from a Donor with HELLP Syndrome Undergoing Hypothermic Oxygenated Machine Perfusion (HOPE) Prior to Implantation.

BACKGROUND Liver transplantation (LT) has become the treatment of choice for patients with end-stage liver disease (ESLD). The organ shortage forced clinicians to use livers from donors with certain risk factors, so-called extended-criteria donor (ECD) organs. Hypothermic oxygenated machine perfusion (HOPE) is an alternative to conventional static cold storage and reduces early allograft injury in ECD organs. In this article we present the case of a 45-year-old man with hepatitis B virus (HBV)-associated cirrhosis and hepatocellular carcinoma (HCC) who underwent successful liver transplantation supported by pretransplant hypothermic oxygenated machine perfusion (HOPE) from a 34-year-old extended-criteria donor (ECD) with hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome. CASE REPORT Liver transplantation was scheduled for a 45-year-old man with hepatocellular carcinoma (HCC) due to hepatitis B virus-induced liver cirrhosis. The organ donor was a 34-year-old woman who had developed intracerebral hemorrhage and brain death due to HELLP syndrome after delivery. Compared to the day of admission to the intensive care unit, a decrease in the donor's transaminases was observed prior to organ procurement. Before transplantation, HOPE was conducted after regular back-table preparation of the graft. LT was performed according to the standard surgical techniques and a standardized immunosuppressive regimen was conducted. In the post-transplant period, transaminases peaked directly after the operation and normalized after 1 week. No major surgical complications occurred. The patient was discharged after a 24-day hospital stay with normal liver function. CONCLUSIONS This case report supports the benefits of using HOPE in ECD organs and it should be considered in livers of donors with HELLP syndrome to improve post-transplant outcome.

Optical coherence tomography combined with convolutional neural networks can differentiate between intrahepatic cholangiocarcinoma and liver parenchyma ex vivo.

PURPOSE: Surgical resection with complete tumor excision (R0) provides the best chance of long-term survival for patients with intrahepatic cholangiocarcinoma (iCCA). A non-invasive imaging technology, which could provide quick intraoperative assessment of resection margins, as an adjunct to histological examination, is optical coherence tomography (OCT). In this study, we investigated the ability of OCT combined with convolutional neural networks (CNN), to differentiate iCCA from normal liver parenchyma ex vivo. METHODS: Consecutive adult patients undergoing elective liver resections for iCCA between June 2020 and April 2021 (n = 11) were included in this study. Areas of interest from resection specimens were scanned ex vivo, before formalin fixation, using a table-top OCT device at 1310 nm wavelength. Scanned areas were marked and histologically examined, providing a diagnosis for each scan. An Xception CNN was trained, validated, and tested in matching OCT scans to their corresponding histological diagnoses, through a 5 × 5 stratified cross-validation process. RESULTS: Twenty-four three-dimensional scans (corresponding to approx. 85,603 individual) from ten patients were included in the analysis. In 5 × 5 cross-validation, the model achieved a mean F1-score, sensitivity, and specificity of 0.94, 0.94, and 0.93, respectively. CONCLUSION: Optical coherence tomography combined with CNN can differentiate iCCA from liver parenchyma ex vivo. Further studies are necessary to expand on these results and lead to innovative in vivo OCT applications, such as intraoperative or endoscopic scanning.

["Stop the bleeding"-Acute bleeding control in injuries to the trunk and extremities]. / "Stop the bleeding" ­ akute Blutungskontrolle bei Verletzungen von Körperstamm und Extremitäten.

Trauma-related blood loss is still associated with a high mortality and is a major factor in the development of a deadly triad consisting of acidosis, hypothermia and coagulopathy. Sources of bleeding occur particularly in the thoracic, abdominal and pelvic regions as well as in the extremities. For control of bleeding a timely identification of the source of bleeding and the initiation of a targeted treatment are essential. The principles are to stop the blood loss as soon as possible and to restore the lost volume to avoid the complications associated with traumatic hemorrhage. Surgical treatment in the acute situation is especially important due to its efficiency. The present article focuses on the current literature with respect to the appropriate diagnostic and treatment measures in the thoracic, abdominal and pelvic regions as well as the extremities and describes the latest scientific insights and developments. Available trauma algorithms are presented and the value of various strategies regarding surgical hemostasis for the thorax and abdomen are shown, whereby organ preservation can increasingly be achieved, particularly in the abdomen. With respect to hemostasis in severe pelvic injuries and injuries to the extremities, the regularly used surgical techniques are described and their values are differentially classified.

The impact of the COVID-19 outbreak on emergency general surgery in the first German "hotspot region" Aachen-Heinsberg-A multicentre retrospective cohort study.

This study aimed to observe the impact of the COVID-19 outbreak on acute general surgery in the first German "hotspot" regions of Heinsberg and Aachen, during the first months of the pandemic. The incidence and severity of acute appendicitis, acute cholecystitis and mechanical bowel obstruction, were compared between March and May 2020 and a control period (same months of the previous three years). Pre-, intra- and postoperative data was compared between three regional hospitals of Heinsberg and the closest maximum care, university hospital. A total of 592 operated patients were included, 141 belonging to the pandemic cohort and 451 to the historic cohort. The pandemic group showed higher rates of clinical peritonitis (38% vs. 27%, p = 0.015), higher rates of mean white blood cell count (13.2±4.4 /nl vs. 12.3±4.7 /nl, p = 0.044) and mean C-reactive protein (60.3±81.1 mg/l vs. 44.4±72.6 mg/l, p = 0.015) preoperatively. Specifically in patients with acute appendicitis, there were less patients with catarrhal appendicitis (23% vs. 35%, p = 0.021) and a tendency towards more advanced histological findings in the pandemic cohort. In the university hospital, a 42% reduction in acute operated cases was observed at the onset of the pandemic (n = 30 in 2020 vs. n = 52 in 2019), whereas in the peripheral hospitals of Heinsberg there was only a 10% reduction (n = 111 in 2020 vs. n = 123 in 2019). The onset of the COVID-19 pandemic in our region was accompanied by advanced preoperative and intraoperative findings in patients undergoing emergency general surgery. A greater reduction in acute operated surgical cases was observed at the university hospital, in contrast to the smaller hospitals of Heinsberg, suggesting a possible shift of emergency patients, requiring immediate operation, from maximum care hospital to the periphery.

Impermeable Atomic Layer Deposition for Sputtering Buffer Layer in Efficient Semi-Transparent and Tandem Solar Cells via Activating Unreactive Substrate.

Atomic layer deposition (ALD) turns out to be particularly attractive technology for the sputtering buffer layer when preparing the semi-transparent (ST) perovskite solar cells (PSCs) and the tandem solar cells. ALD process turns to be island growth when the substrate is unreactive with the ALD reactants, resulting in the pin-hole layer, which causes an adverse effect on anti-sputtering. Here, p-i-n structured PSCs with ALD SnOx as sputtering buffer layer are conducted. The commonly used electron transportation layer (ETL) PCBM in the p-i-n structured PVK solar cell is an unreactive substrate that prevents the layer-by-layer growth for the ALD SnOx . PCBM layer is activated by introducing reaction sites to form impermeable ALD layers. By introducing reaction sites/ALD SnOx as sputtering buffer layer, the authors succeed to fabricate ST-PSCs and perovskite/silicon (double-side polished) tandem solar cells with power conversion efficiency (PCE) of 20.25% and 23.31%, respectively. Besides, the unencapsulated device with reaction sites maintains more than 99% of the initial PCE after aging over 5100 h. This work opens a promising avenue to prepare impermeable layer for stable PSCs, ST-PSCs, tandem solar cells, and the related scale-up solar cells.

Optical coherence tomography and convolutional neural networks can differentiate colorectal liver metastases from liver parenchyma ex vivo.

PURPOSE: Optical coherence tomography (OCT) is an imaging technology based on low-coherence interferometry, which provides non-invasive, high-resolution cross-sectional images of biological tissues. A potential clinical application is the intraoperative examination of resection margins, as a real-time adjunct to histological examination. In this ex vivo study, we investigated the ability of OCT to differentiate colorectal liver metastases (CRLM) from healthy liver parenchyma, when combined with convolutional neural networks (CNN). METHODS: Between June and August 2020, consecutive adult patients undergoing elective liver resections for CRLM were included in this study. Fresh resection specimens were scanned ex vivo, before fixation in formalin, using a table-top OCT device at 1310 nm wavelength. Scanned areas were marked and histologically examined. A pre-trained CNN (Xception) was used to match OCT scans to their corresponding histological diagnoses. To validate the results, a stratified k-fold cross-validation (CV) was carried out. RESULTS: A total of 26 scans (containing approx. 26,500 images in total) were obtained from 15 patients. Of these, 13 were of normal liver parenchyma and 13 of CRLM. The CNN distinguished CRLM from healthy liver parenchyma with an F1-score of 0.93 (0.03), and a sensitivity and specificity of 0.94 (0.04) and 0.93 (0.04), respectively. CONCLUSION: Optical coherence tomography combined with CNN can distinguish between healthy liver and CRLM with great accuracy ex vivo. Further studies are needed to improve upon these results and develop in vivo diagnostic technologies, such as intraoperative scanning of resection margins.

Ultra-Fine Polyethylene Hernia Meshes Improve Biocompatibility and Reduce Intraperitoneal Adhesions in IPOM Position in Animal Models.

(1) Introduction: The intraperitoneal onlay mesh technique (IPOM) is widely used to repair incisional hernias. This method has advantages but suffers from complications due to intraperitoneal adhesion formation between the mesh and intestine. An ideal mesh minimizes adhesions and shows good biocompatibility. To address this, newly developed multifilamentous polyethylene (PET) meshes were constructed from sub-macrophage-sized monofilaments and studied regarding biocompatibility and adhesion formation. (2) Methods: We investigated fine (FPET, 72 filaments, 11 µm diameter each) and ultra-fine multifilament (UFPET, 700 filaments, 3 µm diameter each) polyethylene meshes for biocompatibility in subcutaneous implantation in rats. Adhesion formation was analyzed in the IPOM position in rabbits. Geometrically identical mono-filamentous polypropylene (PP) Bard Soft® PP meshes were used for comparison. Histologic and immune-histologic foreign body reactions were assessed in 48 rats after 7 or 21 days (four mesh types, with two different mesh types per rat; n = 6 per mesh type). Additionally, two different mesh types each were placed in the IPOM position in 24 rabbits to compile the Diamond peritoneal adhesion score after the same timeframes. The biocompatibility and adhesion score differences were analyzed with the Kruskal-Wallis nonparametric statistical test. (3) Results: Overall, FPET and, especially, UFPET showed significantly smaller foreign body granulomas compared to PP meshes. Longer observation periods enhanced the differences. Immunohistology showed no significant differences in the cellular immune response and proliferation. UFPET demonstrated significantly reduced peritoneal adhesion formation compared to all other tested meshes after 21 days. (4) Conclusions: Overall, FPET and, especially, UFPET demonstrated their suitability for IPOM hernia meshes in animal models by improving major aspects of the foreign body reaction and reducing adhesion formation.

Novel Elastic Threads for Intestinal Anastomoses: Feasibility and Mechanical Evaluation in a Porcine and Rabbit Model.

Gastrointestinal anastomoses are an important source of postoperative complications. In particular, the ideal suturing material is still the subject of investigation. Therefore, this study aimed to evaluate a newly developed suturing material with elastic properties made from thermoplastic polyurethane (TPU); Polyvinylidene fluoride (PVDF) and TPU were tested in two different textures (round and a modified, "snowflake" structure) in 32 minipigs, with two anastomoses of the small intestine sutured 2 m apart. After 90 days, the anastomoses were evaluated for inflammation, the healing process, and foreign body reactions. A computer-assisted immunohistological analysis of staining for Ki67, CD68, smooth muscle actin (SMA), and Sirius red was performed using TissueFAXS. Additionally, the in vivo elastic properties of the material were assessed by measuring the suture tension in a rabbit model. Each suture was tested twice in three rabbits; No major surgical complications were observed and all anastomoses showed adequate wound healing. The Ki67+ count and SMA area differed between the groups (F (3, 66) = 5.884, p = 0.0013 and F (3, 56) = 6.880, p = 0.0005, respectively). In the TPU-snowflake material, the Ki67+ count was the lowest, while the SMA area provided the highest values. The CD68+ count and collagen I/III ratio did not differ between the groups (F (3, 69) = 2.646, p = 0.0558 and F (3, 54) = 0.496, p = 0.686, respectively). The suture tension measurements showed a significant reduction in suture tension loss for both the TPU threads; Suturing material made from TPU with elastic properties proved applicable for intestinal anastomoses in a porcine model. In addition, our results suggest a successful reduction in tissue incision and an overall suture tension homogenization.

Bowel Obstruction Due to Stenotic Sigmoid Colon Cancer in a 32-Year-Old Patient Presenting in the Third Trimester of Pregnancy: A Case Report of an Interval Surgical Approach.

BACKGROUND Colorectal cancer among pregnant women is a rare entity. If colon cancer is suspected during pregnancy, the diagnosis is a therapeutic challenge that should be managed by a multidisciplinary team of specialists. Standardized therapeutic models do not exist. In this article we present a case of a pregnant patient with stenotic sigmoid colon adenocarcinoma. We describe the interdisciplinary treatment and the 2-step surgical approach used during pregnancy. CASE REPORT A 32-year-old women in week 28.8 of pregnancy was admitted to the Department of Gynecology and Obstetrics, meeting the standard pregnancy criteria of constipation. After a week of unsuccessful conservative treatment, the patient underwent magnetic resonance imaging (MRI), which disclosed a stenosed segment in the sigmoid colon. After an emergency colonoscopy with biopsy sampling, histological analysis confirmed sigmoid adenocarcinoma. In a multidisciplinary consultation of specialists, in which neonatological and oncological aspects were considered, a 2-step surgical plan was established. In the first step (gestational week 29.8), a loop transverse colostomy with intestinal decompression was performed. In the second step (gestational week 32.8), an elective primary caesarean section followed by open oncological sigmoid resection was performed. No postoperative complications occurred in either step. The neonate was healthy and had a birth weight appropriate for the gestational age. CONCLUSIONS In cases of colorectal cancer during pregnancy, staged surgical approaches should be considered to reduce maternal and fetal morbidity.

Strain Modulation for Light-Stable n-i-p Perovskite/Silicon Tandem Solar Cells.

Perovskite/silicon tandem solar cells are promising to penetrate photovoltaic market. However, the wide-bandgap perovskite absorbers used in top-cell often suffer severe phase segregation under illumination, which restricts the operation lifetime of tandem solar cells. Here, a strain modulation strategy to fabricate light-stable perovskite/silicon tandem solar cells is reported. By employing adenosine triphosphate, the residual tensile strain in the wide-bandgap perovskite absorber is successfully converted to compressive strain, which mitigates light-induced ion migration and phase segregation. Based on the wide-bandgap perovskite with compressive strain, single-junction solar cells with the n-i-p layout yield a power conversion efficiency (PCE) of 20.53% with the smallest voltage deficits of 440 mV. These cells also maintain 83.60% of initial PCE after 2500 h operation at the maximum power point. Finally, these top cells are integrated with silicon bottom cells in a monolithic tandem device, which achieves a PCE of 26.95% and improved light stability at open-circuit.

Machine learning prediction model for postoperative outcome after perforated appendicitis.

PURPOSE: Appendectomy for acute appendicitis is one of the most common operative procedures worldwide in both children and adults. In particular, complicated (perforated) cases show high variability in individual outcomes. Here, we developed and validated a machine learning prediction model for postoperative outcome of perforated appendicitis. METHODS: Retrospective analyses of patients with clinically and histologically verified perforated appendicitis over 10 years were performed. Demographic and surgical baseline characteristics were used as competing predictors of single-patient outcomes along multiple dimensions via a random forest classifier with stratified subsampling. To assess whether complications could be predicted in new, individual cases, the ensuing models were evaluated using a replicated 10-fold cross-validation. RESULTS: A total of 163 patients were included in the study. Sixty-four patients underwent laparoscopic surgery, whereas ninety-nine patients got a primary open procedure. Interval from admission to appendectomy was 9 ± 12 h and duration of the surgery was 74 ± 38 min. Forty-three patients needed intensive care treatment. Overall mortality was 0.6 % and morbidity rate was 15%. Severe complications as assessed by Clavien-Dindo > 3 were predictable in new cases with an accuracy of 68%. Need for ICU stay (> 24 h) could be predicted with an accuracy of 88%, whereas prolonged hospitalization (greater than 7-15 days) was predicted by the model with an accuracy of 76%. CONCLUSION: We demonstrate that complications following surgery, and in particular, health care system-related outcomes like intensive care treatment and extended hospitalization, may be well predicted at the individual level from demographic and surgical baseline characteristics through machine learning approaches.

Two Polyurethane Adhesives for PVDF Fixation Show Superior Biocompatibility in a Rat Model.

BACKGROUND: The current standard for open and laparoscopic repair of incisional hernia consist of an abdominal wall augmentation by mesh implantation. However, the ideal fixation method of the prothesis material remains under discussion, due to potential complications of conventional fixation methods such as chronic abdominal pain or intestinal obstruction. As the use of adhesive based mesh fixation is an option of growing interest, the aim of this experimental study was to investigate the strength and biocompatibility of two newly developed polyurethane-based adhesives in comparison to a cyanoacrylatic adhesive, which is currently in clinical use. METHODS: Two experimental polyurethane/urea-based adhesives (Adhesive-A and Adhesive-B) were compared to a conventional cyanoacrylatic adhesive and an untreated control group. Biomechanical testing was carried out using a pull-out test in uniaxial tensile mode, while biocompatibility assessment was performed in a rat model with 40 Sprague-Dawley rats receiving a subcutaneous implanted PVDF mesh fixed by the corresponding adhesive. Histological and immunohistochemical analysis by a Tissue FAXS system examined the tissue integration of the mesh/adhesive combination and characterized the foreign body reaction. RESULTS: Biomechanical testing of the mesh/adhesive combinations showed a minimal strength of 15.08 N without a significant difference between the groups. Cellular penetration into the mesh/adhesive interface was significantly improved after application of polyurethane adhesives and Adhesive-A showed a significantly lower migration of CD68 positive cells to the adhesive sites compared to cyanoacrylate after 7 days. CONCLUSION: The developed polyurethane-based adhesives are a promising alternative with sufficient adhesive strength and superior short-term biocompatibility to cyanoacrylate.

Is sarcopenia a risk factor for reduced diaphragm function following hepatic resection? A study protocol for a prospective observational study.

INTRODUCTION: Sarcopenia is associated with reduced pulmonary function in healthy adults, as well as with increased risk of pneumonia following abdominal surgery. Consequentially, postoperative pneumonia prolongs hospital admission, and increases in-hospital mortality following a range of surgical interventions. Little is known about the function of the diaphragm in the context of sarcopenia and wasting disorders or how its function is influenced by abdominal surgery. Liver surgery induces reactive pleural effusion in most patients, compromising postoperative pulmonary function. We hypothesise that both major hepatic resection and sarcopenia have a measurable impact on diaphragm function. Furthermore, we hypothesise that sarcopenia is associated with reduced preoperative diaphragm function, and that patients with reduced preoperative diaphragm function show a greater decline and reduced recovery of diaphragm function following major hepatic resection. The primary goal of this study is to evaluate whether sarcopenic patients have a reduced diaphragm function prior to major liver resection compared with non-sarcopenic patients, and to evaluate whether sarcopenic patients show a greater reduction in respiratory muscle function following major liver resection when compared with non-sarcopenic patients. METHODS AND ANALYSIS: Transcostal B-mode, M-mode ultrasound and speckle tracking imaging will be used to assess diaphragm function perioperatively in 33 sarcopenic and 33 non-sarcopenic patients undergoing right-sided hemihepatectomy starting 1 day prior to surgery and up to 30 days after surgery. In addition, rectus abdominis and quadriceps femoris muscles thickness will be measured using ultrasound to measure sarcopenia, and pulmonary function will be measured using a hand-held bedside spirometer. Muscle mass will be determined preoperatively using CT-muscle volumetry of abdominal muscle and adipose tissue at the third lumbar vertebra level (L3). Muscle function will be assessed using handgrip strength and physical condition will be measured with a short physical performance battery . A rectus abdominis muscle biopsy will be taken intraoperatively to measure proteolytic and mitochondrial activity as well as inflammation and redox status. Systemic inflammation and sarcopenia biomarkers will be assessed in serum acquired perioperatively. ETHICS AND DISSEMINATION: This trial is open for recruitment. The protocol was approved by the official Independent Medical Ethical Committee at Uniklinik (Rheinish Westphälische Technische Hochschule (RWTH) Aachen (reference EK309-18) in July 2019. Results will be published via international peer-reviewed journals and the findings of the study will be communicated using a comprehensive dissemination strategy aimed at healthcare professionals and patients. TRIAL REGISTRATION NUMBER: ClinicalTrials. gov (EK309-18); Pre-results.

Incisional hernia repair by synthetic mesh prosthesis in patients with inflammatory bowel disease: a comparative analysis.

BACKGROUND: Patients with inflammatory bowel disease (IBD) have a high-life time risk undergoing abdominal surgery and are prone to develop incisional hernias (IH) in the postoperative course. Therefore, we investigated the role of IBD as perioperative risk factor in open ventral hernia repair (OVHR) as well as the impact of IBD on hernia recurrence during postoperative follow-up. METHODS: The postoperative course of 223 patients (Non-IBD (n = 199) and IBD (n = 34)) who underwent OVHR were compared by means of extensive group comparisons and binary logistic regressions. Hernia recurrence was investigated in the IBD group according to the Kaplan-Meier method and risk factors for recurrence determined by Cox regressions. RESULTS: General complications (≥ Clavien-Dindo I) occurred in 30.9% (72/233) and major complications (≥ Clavien-Dindo IIIb) in 7.7% (18/233) of the overall cohort with IBD being the single independent risk-factor for major complications (OR = 4.2, p = 0.007). Further, IBD patients displayed a recurrence rate of 26.5% (9/34) after a median follow-up of 36 months. Multivariable analysis revealed higher rates of recurrence in patients with ulcerative colitis (UC, 8/15, HR = 11.7) compared to patients with Crohn's disease (CD, 1/19, HR = 1.0, p = 0.021). CONCLUSION: IBD is a significant risk factor for major postoperative morbidity after OVHR. In addition, individuals with IBD show high rates of hernia recurrence over time with UC patients being more prone to recurrence than patients with CD.

Stable Organic Passivated Carbon Nanotube-Silicon Solar Cells with an Efficiency of 22.

The organic passivated carbon nanotube (CNT)/silicon (Si) solar cell is a new type of low-cost, high-efficiency solar cell, with challenges concerning the stability of the organic layer used for passivation. In this work, the stability of the organic layer is studied with respect to the internal and external (humidity) water content and additionally long-term stability for low moisture environments. It is found that the organic passivated CNT/Si complex interface is not stable, despite both the organic passivation layer and CNTs being stable on their own and is due to the CNTs providing an additional path for water molecules to the interface. With the use of a simple encapsulation, a record power conversion efficiency of 22% is achieved and a stable photovoltaic performance is demonstrated. This work provides a new direction for the development of high-performance/low-cost photovoltaics in the future and will stimulate the use of nanotubes materials for solar cells applications.

[Sarcopenia and Cachexia-associated Risk in Surgery]. / Der Einfluss von Kachexie und Sarkopenie auf das postoperative Outcome.

Cachexia is defined as a multifactorial syndrome characterised by involuntary progressive weight loss due to a decrease in skeletal muscle mass, with or without a reduction in adipose tissue. The breakdown of muscle tissue is known as sarcopenia. This is clinically defined as loss of muscle mass and/or muscle strength, with loss of muscle strength being more important than muscle mass. Cachexia is responsible for the death of at least 20% of all cancer patients. The incidence in these patients varies, depending on the type of disease, between 80% for patients with gastric and pancreatic cancer, 50% for patients with lung, colon and prostate cancer, and about 40% for patients with breast cancer or leukemia. It is often difficult to distinguish between tumour-associated cachexia and cachexia caused by side effects and complications of oncological therapy. The main clinical feature of cachexia is involuntary weight loss, but this does not always manifest itself clinically, making it much more difficult to identify patients at risk. Not only the long-term outcome of the patient is influenced by cachexia and sarcopenia. Immediate postoperative complication rates (morbidity) are also increased and have profound effects on the burden of disease and the suffering of patients after surgical treatment. Cachexia, sarcopenia and myosteatosis are therefore highly relevant parameters for everyday clinical practice, which have a significant influence on the postoperative outcome of the patient. Several tools have been developed to aid the identification of patients with nutritional risk, i.e. involuntary weight loss, reduced muscle strength and physical condition. Such measures should be a part of our daily clinical routine to ensure the identification of patients with the highest postoperative risk. Novel preconditioning treatment may be beneficial to certain patient groups to reduce postoperative morbidity.

Cross-section modified and highly elastic sutures reduce tissue incision and show comparable biocompatibility: in-vitro and in-vivo evaluation of novel thermoplastic urethane surgical threads.

Surgical sutures are indispensable for a vast majority of operative procedures. An ideal suture is characterized by high tissue compliance without cutting into the mended tissue and optimal biocompatibility. Therefore, we assessed these mechanical and biological properties for novel elastic thermoplastic polyurethane (TPU) and cross-sectional modified "snowflake" sutures. Circular and "snowflake"-shaped TPU threads were manufactured and compared to similar surface modified polyvinylidene fluoride (PVDF) sutures. Regular PVDF sutures were used as the control group. Single-axis tensile test with and without gelatinous tissue surrogates were performed to evaluate the suture incision into the specimens. Biocompatibility was evaluated by subcutaneous implantation (n = 18) in rats for 7 and 21 days. Histology and immunohistology was conducted for assessment of the foreign body reaction. Regular and modified TPU threads showed a significant reduction of incision into the tissue surrogates compared to the control. Both TPU sutures and the modified PVDF sutures achieved comparable biocompatibility versus regular PVDF threads. Detailed histology revealed novel tissue integration into the notches of the surface modified sutures, we termed this newly shaped granuloma "intrafilamentous" granuloma. Elastic TPU threads showed a significant reduction of tissue surrogate incision and suture tension loss. Biocompatibility did not significantly differ from standard PVDF. Histology demonstrated tissue ingrowth following the surface modification of the suture referred to as "intrafilamentous" granuloma. Further in vivo studies are required to illuminate the exact potential of the new sutures to optimize intestinal anastomosis.

First Result of a Tailored Progressive Multistep Approach for the Treatment of Aorto-esophageal Fistulae.

BACKGROUND: Aorto-esophageal fistulae (AEFs) are a rare but serious and life-threatening disease of the mediastinum. Especially, AEF in the presence of infected stent grafts, for example, after thoracic endovascular aortic repair (TEVAR) is only curable by a multistage interdisciplinary surgical approach. This study presents the results of our four-stage approach consisting of bridging TEVAR, esophagectomy, complete stent removal followed by total bovine tube aortic replacement (TBTAR), and finally esophageal reconstruction. METHODS: A case series of four patients from our department receiving a four-stage treatment of AEF is presented in this study. Retrospective database analysis focusing on overall survival, duration of intensive care unit and total hospital stay until discharge, complications, surgical time frame, and completion of chosen surgical treatment course was performed. RESULTS: Overall, four patients surgically treated for AEF since May 2015 were included. A 30-day mortality was 0%, and overall survival at 1 year was 75%. All patients survived more than 5 months and could be discharged after TEVAR and esophagectomy. TBTAR could be performed in two of four patients (50%). Esophageal reconstruction was completed in all patients. Average follow-up was 20.3 ± 1.7 months or until death. CONCLUSION: The acute management of AEF using this approach seems satisfactory, especially for reducing acute short-term mortality. Complete restoration of the circulatory system and digestive tract remains challenging and is associated with high morbidity. We support the application of bridging TEVAR with a staggered approach to further surgical treatment individually tailored to the patient.