Observation of out-of-plane vibrations in few-layer graphene

We report the observation of layer breathing mode (LBM) vibrations in few-layer graphene (FLG) samples of thickness from 2 to 6 layers, exhibiting both Bernal (AB) and rhombohedral (ABC) stacking order. The LBM vibrations are identified using a Raman combination band lying around 1720 cm-1. From double resonance theory, we identify the feature as the LOZO' combination mode of the out-of-plane LBM (ZO') and the in-plane longitudinal optical mode (LO). The LOZO' Raman band is found to exhibit multiple peaks, with a unique line shape for each layer thickness and stacking order. These complex line shapes of the LOZO'-mode arise both from the material-dependent selection of different phonons in the double-resonance Raman process and from the detailed structure of the different branches of LBM in FLG.Comment: 17 pages, 7 figures, supplemental material include

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Total Parenteral Nutrition Successfully Treating Black Esophagus Secondary to Hypovolemic Shock

We present a patient who developed black esophagus secondary to hypovolemic shock and was placed on total parenteral nutrition for three weeks after hospital discharge. The area of interest is the multimodal approach used in treatment of this noncompliant patient. Even with a high mortality rate, this case illustrates a successful outcome of a patient who responded to appropriate immediate therapy resulting in complete resolution of the necrosis with no further development of complications

Lung Adenocarcinoma Presenting as Worsening of Chronic Neck Pain—A Cautionary Tale

Introduction: Neck pain is a common musculoskeletal problem that up to 70% of the world population will experience at some point in their lives. Intramedullary spinal cord metastasis is an exceedingly rare complication of malignancy that affects less than 1% of all patients with cancer. Case report: We report a case of a 61-year-old man who presented to primary care clinic with 1-month history of worsening neck pain with associated neurologic deficits. Despite initial conservative management, the patient continued to have progressive worsening of sensory and motor deficits. Magnetic resonance imaging of the cervical spine showed vasogenic edema of the brain and spinal cord and nodularity at the C4-C5 level. A computed tomography of the chest showed a dense lesion in the left lower lobe of the lung; histopathology of the biopsied specimen was consistent with moderately differentiated lung adenocarcinoma. Conclusions: A high index of suspicion is necessary when chronic neck pain acutely worsens, changes in character, or is accompanied by neurologic deficits. These clinical signs warrant further investigation into a secondary cause of neck pain. Intramedullary spinal cord metastases are rare complications of systemic cancer that commonly present with neck pain and upper extremity paraesthesias; early diagnosis and management are necessary to prevent complications such as spinal cord hemisection syndrome or spinal cord transection

Prospective study on the efficacy of endoscopic through-the-scope tack and suture system for gastric peroral endoscopic myotomy mucosal incision site closure

Background and study aims Mucosal closure after gastric per-oral endoscopic myotomy (G-POEM) can be difficult due to the thick gastric mucosa. We evaluated the use of a novel through-the-scope (TTS) suture system for G-POEM mucosotomy closure. Patients and methods This was a single-center prospective study on consecutive patients who underwent G-POEM with TTS suture closure between February 2022 and August 2022. Technical success was defined as complete mucosotomy closure with TTS suture alone. On subgroup analysis, we compared performance on TTS suturing between the advanced endoscopist and the advanced endoscopy fellow (AEF) under supervision. Results Thirty-six consecutive patients (median age 60 years, interquartile range [IQR] 48.5–67], 72 % women) underwent G-POEM with TTS suture of the mucosotomy. Median mucosal incision length was 2 cm (IQR: 2–2.5). Mean mucosal closure and total procedure time were 17.5 ± 10.8 and 48.4 ± 16.8 minutes, respectively. Technical success was achieved in 24 patients (66.7 %) and 100 % of the cases were adequately closed with a combination of TTS suture and clips. When compared to the advanced endoscopist, the AEF required > 1 TTS suture system for complete closure significantly more frequently (66.7 % vs. 8.3 %, P = 0.009) and more time for mucosal closure (20.4 ± 12.1 vs. 11.9 ± 4.9 minutes, P = 0.03). Conclusions TTS suturing is effective and safe for G-POEM mucosal incision closure. With experience, technical success is high, and most closures may be achieved using a single TTS suture system alone, which has important cost and time implications. Additional comparative trials with other closure devices are need1ed

Novel single‐operator through‐the‐scope traction device for endoscopic submucosal dissection: Outcomes of a multicenter randomized pilot ex‐vivo study in trainees with limited endoscopic submucosal dissection experience (with video)

ObjectivesEndoscopic submucosal dissection is a technically demanding procedure. The pilot study aimed to prospectively evaluate the efficacy and safety of a novel single-operator through-the-scope dynamic traction device among trainees with limited endoscopic submucosal dissection (ESD) experience.MethodsRandomized, controlled, pilot study comparing traction-assisted ESD (T-ESD) versus conventional ESD (C-ESD) in an ex-vivo porcine stomach model. Trainees were randomized to group 1 (T-ESD followed by C-ESD) and group 2 (C-ESD followed by T-ESD). Lesions were created on the gravity-dependent area of the stomachs. The primary outcome was submucosal dissection speed. Secondary outcomes included differences in en-bloc resection, adverse events, and workload, assessed by the National Aeronautical and Space Administration Task Load Index (NASA-TLX).ResultsFive trainees performed two T-ESD and two C-ESD each, for a total of 20 procedures. Submucosal dissection speed was significantly faster in the T-ESD group compared to the C-ESD group (43.32 ± 22.61 vs. 24.19 ± 15.86 mm2/min; p = 0.042). En-bloc resection was achieved in 60% with T-ESD and 70% with C-ESD (p = 1.00). The muscle injury rate was higher in the C-ESD group (50% vs. 10%; p = 0.21) with 1 perforation reported with C-ESD and none with T-ESD. NASA-TLX physical demand was lower with T-ESD compared to C-ESD (4.5 ± 2.17 vs. 6.9 ± 2.50; p = 0.03).ConclusionT-ESD resulted in faster submucosal dissection and less physical demand when compared to C-ESD, as performed by trainees in an ex-vivo gravity-dependent model. Future studies are needed to assess its role in human ESD cases