This paper reports the enhancement of long-term oxidation of copper at room temperature by a graphene coating. Previous studies showed that graphene is an effective anticorrosion barrier against ...short-term thermal and electrochemical oxidation of metals. Here, we show that a graphene coating can, on the contrary, accelerate long-term oxidation of an underlying copper substrate in ambient atmosphere at room temperature. After 6 months of exposure in air, both Raman spectroscopy and energy-dispersive X-ray spectroscopy indicated that graphene-coated copper foil had a higher degree of oxidation than uncoated foil, although X-ray photoelectron spectroscopy showed that the surface concentration of Cu2+ was higher for the uncoated sample. In addition, we observed that the oxidation of graphene-coated copper foil was not homogeneous and occurred within micrometer-sized domains. The corrosion enhancement effect of graphene was attributed to its ability to promote electrochemical corrosion of copper.
It is generally accepted that supported graphene is hydrophobic and that its water contact angle is similar to that of graphite. Here, we show that the water contact angles of freshly prepared ...supported graphene and graphite surfaces increase when they are exposed to ambient air. By using infrared spectroscopy and X-ray photoelectron spectroscopy we demonstrate that airborne hydrocarbons adsorb on graphitic surfaces, and that a concurrent decrease in the water contact angle occurs when these contaminants are partially removed by both thermal annealing and controlled ultraviolet-O3 treatment. Our findings indicate that graphitic surfaces are more hydrophilic than previously believed, and suggest that previously reported data on the wettability of graphitic surfaces may have been affected by unintentional hydrocarbon contamination from ambient air.
Laparoscopic redo inguinal hernia (LRIH) repairs are fraught with challenges as the pre-peritoneal space is violated due to previous surgery and the presence of mesh. The purpose of this study was to ...present the feasibility and safety of LRIH in a series of patients with recurrent inguinal hernia following previous endolaparoscopic repair and present technical experiences and clinical outcomes in this subset of patients.
This was a retrospective study from a prospective database of 16 patients who underwent LRIH between March 2014 and December 2020. The decision to do a redo laparoscopic surgery was undertaken after a detailed discussion with the patient. The operative details, challenges faced and tips to overcome difficulties have been explained in detail.
Out of 16 patients (mean age 49.5 years, all men), 15 underwent laparoscopic redo trans-abdominal pre-peritoneal (TAPP) mesh repair and 1 underwent laparoscopic enhanced-view totally extra-peritoneal (eTEP) mesh repair. The mean operating time was 68.5 min for unilateral, 115 min for bilateral TAPP and 90 min for eTEP. The main contributing factors for recurrences were mesh migration, insufficient size of the mesh and inadequate fixation. There was no conversion to open repair. The duration of stay was 1-2 days. There was no documented re-recurrence during the follow-up period of 2-9 years.
Based on our experience, redo laparoscopic inguinal hernia mesh repair after previous endolaparoscopic repair is feasible, effective and safe in experienced hands.
High electrochemical reactivity is required for various energy and sensing applications of graphene grown by chemical vapor deposition (CVD). Herein, we report that heterogeneous electron transfer ...can be remarkably fast at CVD‐grown graphene electrodes that are fabricated without using the conventional poly(methyl methacrylate) (PMMA) for graphene transfer from a growth substrate. We use nanogap voltammetry based on scanning electrochemical microscopy to obtain very high standard rate constants k0≥25 cm s−1 for ferrocenemethanol oxidation at polystyrene‐supported graphene. The rate constants are at least 2–3 orders of magnitude higher than those at PMMA‐transferred graphene, which demonstrates an anomalously weak dependence of electron‐transfer rates on the potential. Slow kinetics at PMMA‐transferred graphene is attributed to the presence of residual PMMA. This unprecedentedly high reactivity of PMMA‐free CVD‐grown graphene electrodes is fundamentally and practically important.
Large‐area graphene grown by chemical vapor deposition shows very high electrochemical reactivity when polystyrene is employed for electrode fabrication instead of the conventional poly(methyl methacrylate). Ultrafast oxidation of ferrocenemethanol (FcMeOH) is monitored by nanogap voltammetry based on scanning electrochemical microscopy, yielding unprecedentedly high standard electron‐transfer rate constants (k0≥25 cm s−1).
Anastomotic stricture formation at the biliary-enteric anastomotic site is the most common complication of Roux-en-Y hepaticojejunostomy performed for post-cholecystectomy bile duct injuries. ...Percutaneous trans-hepatic biliary drainage followed by balloon dilatation is an available minimally invasive option to manage this complication. This will require multiple sittings along with the requirement of extracorporeal shockwave lithotripsy to break the calculi before extracting them through the matured percutaneous tract. This leads to multiple hospital visits with prolonged treatment course. To provide a one stop solution, we adopted a simplified minimally invasive technique of combining laparoscopic and endoscopic approach to dilate the hepaticojejunostomy stricture as well as to extract the stones in the same sitting. A young female presented with cholangitis and hepatolithiasis following a hepaticojejunostomy done for bile duct injury 3 years back. In view of hepatolithiasis proximal to anastomotic stricture, a new technique of Laparo-endoscopy was performed to dilate the hepaticojejunostomy stricture and extract the calculi in the same sitting. This was preferred over percutaneous trans-hepatic biliary drainage which would have required multiple sessions. The patient has been followed up over a period of 4 years. All her parameters have remained within normal limits during the follow-up period. The Laparo-endoscopic approach is safe, feasible, and can provide a one stop solution in selected cases of biliary-enteric anastomotic stricture.
Persistent Müllerian duct syndrome is an intersex disorder which occurs due to the failure of regression of Müllerian structures in genotypical and phenotypical males. It is a rare disorder of male ...internal pseudohermaphroditism with normal secondary sexual characters and XY karyotype. We report a male patient with the diagnosis of bilateral inguinoscrotal hernia with cryptorchidism scheduled for laparoscopic bilateral transabdominal pre-peritoneal (TAPP) mesh repair with bilateral orchidopexy. Intra-operatively, there was a rudimentary uterus with tubes on both sides. Bilateral testicular biopsy was taken to confirm the presence of testicular tissue and to exclude malignancy and ovarian tissue. Hernia surgery was deferred in the first stage. After 2 weeks, he underwent laparoscopic bilateral orchidopexy with TAPP mesh repair. At 6-year follow-up, there is no recurrence of hernia or features of malignancy in the retained testis.
We report an experimental study on the fabrication and characterization of hierarchical graphene/metal grid structures for transparent conductors. The hierarchical structure allows for uniform and ...local current conductivity due to the graphene and exhibits low sheet resistance because the microscale silver grid serves as a conductive backbone. Our samples demonstrate 94% diffusive transmission with a sheet resistance of 0.6 Ω/sq and a direct current to optical conductivity ratio σdc/σop of 8900. The sheet resistance of the hierarchical structure may be improved by over 3 orders of magnitude and with little decrease in transmission compared with graphene. Furthermore, the graphene protects the silver grid from thermal oxidation and better maintains the sheet resistance of the structure at elevated temperature. The graphene also strengthens the adhesion of the metal grid with the substrate such that the structure is more resilient under repeated bending.
Acquired perineal and parastomal hernias are rare but are known complications following extensive pelvic surgeries for oncological reasons with diversion urostoma or colostomy. The occurrence of both ...these hernias in a same patient is even rarer, with exact incidence unknown. Most of the literature describe case reports of combined perineal and parastomal hernias following abdominoperineal resection, which was managed either by open, laparoscopic or by robotic approach. We herein describe the first reported case of perineal and parastomal hernia in a 76-year-old woman following anterior pelvic exenteration and ileal conduit for carcinoma urinary bladder which was managed by total laparoscopic approach with favorable outcome at 1-year follow-up.
Transcriptome-wide association studies (TWAS) are popular approaches to test for association between imputed gene expression levels and traits of interest. Here, we propose an integrative method ...PUMICE (Prediction Using Models Informed by Chromatin conformations and Epigenomics) to integrate 3D genomic and epigenomic data with expression quantitative trait loci (eQTL) to more accurately predict gene expressions. PUMICE helps define and prioritize regions that harbor cis-regulatory variants, which outperforms competing methods. We further describe an extension to our method PUMICE +, which jointly combines TWAS results from single- and multi-tissue models. Across 79 traits, PUMICE + identifies 22% more independent novel genes and increases median chi-square statistics values at known loci by 35% compared to the second-best method, as well as achieves the narrowest credible interval size. Lastly, we perform computational drug repurposing and confirm that PUMICE + outperforms other TWAS methods.
Systemic lupus erythematosus is a heritable autoimmune disease that predominantly affects young women. To improve our understanding of genetic etiology, we conduct multi-ancestry and multi-trait ...meta-analysis of genome-wide association studies, encompassing 12 systemic lupus erythematosus cohorts from 3 different ancestries and 10 genetically correlated autoimmune diseases, and identify 16 novel loci. We also perform transcriptome-wide association studies, computational drug repurposing analysis, and cell type enrichment analysis. We discover putative drug classes, including a histone deacetylase inhibitor that could be repurposed to treat lupus. We also identify multiple cell types enriched with putative target genes, such as non-classical monocytes and B cells, which may be targeted for future therapeutics. Using this newly assembled result, we further construct polygenic risk score models and demonstrate that integrating polygenic risk score with clinical lab biomarkers improves the diagnostic accuracy of systemic lupus erythematosus using the Vanderbilt BioVU and Michigan Genomics Initiative biobanks.
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