Identification of mono-and few- layer graphene: Raman study

International audienceIn this theoretical work, the Raman spectra were analyzed by considering the origin of the G peak, its shape, position and relative intensity as a function of the number of graphene layers. By using the spectral moment's method, the Raman spectra of mono, bi and few-layers of graphene are calculated and a good agreement was found with group theory concerning the number of the Raman-active modes and the Raman measurements. Our results provide a Raman analysis to evaluate the number of layers in multilayer graphene

Analysis of a SIRI epidemic model with distributed delay and relapse

We investigate the global behaviour of a SIRI epidemic model with distributed delay and relapse. From the theory of functional differential equations with delay, we prove that the solution of the system is unique, bounded, and positive, for all time. The basic reproduction number $R_{0}$ for the model is computed. By means of the direct Lyapunov method and LaSalle invariance principle, we prove that the disease free equilibrium is globally asymptotically stable when $R_{0} < 1$. Moreover, we show that there is a unique endemic equilibrium, which is globally asymptotically stable, when $R_{0} > 1$.Comment: This is a preprint of a paper whose final and definite form is with 'Statistics Opt. Inform. Comput.', Vol. 7, No 2 (2019). See [http://www.iapress.org]. Submitted 26/July/2018; Revised and Accepted 22/Dec/201

Incidence and Outcome of the Radial Nerve Injury following Open Fracture of the Humerus

Background: Radial nerve injury is the most common peripheral nerve injury associated with humeral shaft fracture and can result in significant motor impairment of the arm and the wrist.Objectives: To evaluate the incidence, pattern and outcome of the radial nerve injury following open fracture of the humerus.Material and Methods: This is a multicentre cross-sectional descriptive study. It included all patients with radial nerve injuries following open fracture of the humerus presented to orthopaedic departments of the major hospitals in Khartoum State, Sudan during the period June 2009 - June 2013. Collected data were processed using SPSS computer package version 17.Result: A total of 48 patients were included, 34 males and 14 females (ratio 1.5: 1). Mean age ± standard error of mean of 30.71 ± 1.78 years (ranged 4 – 64 years). About 60.4% of injuries were due to gunshot and 24 (50.0%) patients were from conflict areas. Most of the injuries were in left side in about 68.8% of patients. The common patterns of the humeral fractures associated with radial nerve injury were open comminuted and transverse of middle or distal part. Neurapraxia was common type of radial nerve injury in about 89.6%. About 91.7% of the patients were treated conservatively and 81.3% of them recovered completely.Conclusions: Most of the radial nerve injuries following open fracture of the humerus were caused by gunshot injury in male soldiers mainly in the distal and middle parts. The fractures were mainly displaced comminuted and transverse types. The commonest type of radial nerve palsy was neurapraxia in 89.6% of cases. Most of the patients were treated conservatively and 81.3% of them recovered spontaneously after the first two months.Keywords: Neurapraxia, Repair, Recovery, Gun shot, Sudan

An e-learning reproductive health module to support improved student learning and interaction: a prospective interventional study at a medical school in Egypt

<p>Abstract</p> <p>Background</p> <p>The Public Health (PH) course at the medical college of Cairo University is based on traditional lectures. Large enrollment limits students' discussions and interactions with instructors.</p> <p>Aim</p> <p>Evaluate students' learning outcomes as measured by improved knowledge acquisition and opinions of redesigning the Reproductive Health (RH) section of the PH course into e-learning and assessing e-course utilization.</p> <p>Methods</p> <p>This prospective interventional study started with development of an e-learning course covering the RH section, with visual and interactive emphasis, to satisfy students' diverse learning styles. Two student groups participated in this study. The first group received traditional lecturing, while the second volunteered to enroll in the e-learning course, taking online course quizzes. Both groups answered knowledge and course evaluation questionnaires and were invited to group discussions. Additionally, the first group answered another questionnaire about reasons for non-participation.</p> <p>Results</p> <p>Students participating in the e-learning course showed significantly better results, than those receiving traditional tutoring. Students who originally shunned the e-course expressed eagerness to access the course before the end of the academic year. Overall, students using the redesigned e-course reported better learning experiences.</p> <p>Conclusions</p> <p>An online course with interactivities and interaction, can overcome many educational drawbacks of large enrolment classes, enhance student's learning and complement pit-falls of large enrollment traditional tutoring.</p

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10&nbsp;years; 78.2% included were male with a median age of 37&nbsp;years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Structure and Raman Spectra of C60 and C70 Fullerenes Encased into Single-Walled Boron Nitride Nanotubes: A Theoretical Study

International audienceWe report the structures and the nonresonant Raman spectra of hybrid systems composed of carbon fullerenes (C60 and C70) encased within single walled boron nitride nanotube. The optimal structure of these systems are derived from total energy minimization using a convenient Lennard-Jones expression of the van derWaals intermolecular potential. The Raman spectra have been calculated as a function of nanotube diameter and fullerene concentration using the bond polarizability model combined with the spectral moment method. These results should be useful for the interpretation of the experimental Raman spectra of boron nitride nanotubes encasing C60 and C70 fullerenes

PDF Research Detection of hiatal hernias: comparison of high-resolution manometry and physician reported in an obese-predominant population

Background The diagnosis of a hiatal hernia (HH) can be made by barium oesophagram or upper endoscopy. Data regarding the ability of high-resolution manometry (HRM) with oesophageal pressure topography (OPT) to identify HH remains limited. We aim to assess the diagnostic accuracy of the automated localisation on high-resolution manometry compared with physician visual interpretation on the detection of HH. Methods Patients (n=181) from West Virginia, Pennsylvania, Maryland, Virginia and Ohio, undergoing HRM with OPT from 1 January 2015 to 1 December 2017 were reviewed. The BMIs of this patient population are of the highest in the USA. Demographics, presenting symptoms, laboratory data, endoscopic findings, radiographic findings, and HRM findings were collected. Diagnosis of HH through HRM automated identification of oesophageal landmarks were compared with diagnosis by physician visual interpretation of OPT. Results Automated identification of HH using HRM had high specificity (99.1%), but low sensitivity (11.4%). Physician visual interpretation of OPT similarly had high specificity (82.9%, 83.8%), but low sensitivity (30.0%, 28.6%). Automated identification of HH had a greater positive predictive value (88.9%) compared with physician visual interpretation (52.5%, 52.6%) but was found to have a similar negative predictive value (63.9%) as physician visual interpretation (65.3%, 65.0%). Conclusion Compared with physician visual interpretation of OPT, automated identification of HH was more specific, but less sensitive in the diagnosis of HH. Use of automated identification of HH using HRM alone may lead to an increased number of false negatives, and subsequent underdiagnosis of this condition

The Expression of Circulating miR-497 and Metadherin in Hepatocellular Carcinoma: Relation to the Tumor Characteristics and Patients’ Survival

Objectives: This study aimed to evaluate the prognostic significance and relationship of miR-497 and metadherin to hepatocellular carcinoma (HCC) tumor characteristics and patients’ survival. Methods: This study enrolled 120 (60 HCC patients and 60 healthy) subjects. Serum miR-497 and metadherin mRNA relative expression were analyzed by real-time quantitative reverse transcription polymerase chain reaction. The overall survival (OS) of HCC patients was assessed using the Kaplan–Meier curve and log-rank test. Results: Serum miR-497 showed statistically significant downregulation in HCC patients compared to controls (p &lt; 0.001). Serum metadherin mRNA relative expression was significantly upregulated in HCC patients compared to controls (p &lt; 0.001). Both serum miR-497 and metadherin mRNA expression were significantly associated with the number of tumor foci (p = 0.028 and 0.001, respectively), tumor size (p = 0.022 and &lt;0.001, respectively), nodal metastasis (p = 0.003 and 0.003, respectively), distant metastasis (p = 0.003 and 0.003, respectively), vascular invasion (p = 0.040 and &lt;0.001, respectively), and BCLC staging (p = 0.043 and 0.004, respectively). The overall survival was lower in patients with low miR-497 expression (p = 0.046) and in patients with high metadherin expression (p &lt; 0.001). Conclusions: The expression levels of miR-497 showed downregulation in HCC patients, but metadherin expression showed upregulation. Both markers were inversely related and closely correlated with tumor characteristics and patients’ survival