Multiscale investigation of pore structure heterogeneity in carbonate rocks using digital imaging and SCAL measurements: A case study from Upper Jurassic limestones, Abu Dhabi, UAE.

This study presents a comprehensive analysis of rock properties for a selected group of six carbonate reservoir rock samples revealing complex structures at various length scales. Experimental laboratory methods as well as image analysis techniques were conducted in this study to characterize the macro- and micro-pores in mud- and grain-dominated limestones samples from the Upper Jurassic Arab Formation (Arab D member). Mercury Injection Capillary Pressure (MICP), porosimeter, and permeameter lab measurements were employed to assess the pore network heterogeneity and complexity. In addition, a multiscale rock imaging approach was implemented to detect grain and pore phases at several length scales using Thin Sections (TS), Scanning Electron Microscopy (SEM), Focused Ion Beam Scanning Electron Microscopy (FIB-SEM), as well as 3D X-ray Computed Tomography (CT), and micro-computed tomography images (MCT). Furthermore, the multifractal analysis method was applied on the MICP and FIB-SEM to characterize quantitatively the heterogeneity of the pores in the studied samples. Heterogeneous samples 3R, 4M, 5W, and 6M display the highest non-uniformity degree Δα values, falling within the range of [1.21, 1.39] based on FIB-SEM images. Samples 1G, 2R, 3R, and 5W exhibit more heterogeneous pore structure, with Δα values ranging from 0.73 to 1.49 based on the MICP experiments. The results and findings confirm the effectiveness of multifractal parameters Δα and the asymmetry degree in the vertical axis Δf(α) in quantifying and characterizing rock heterogeneity.

Experimental and digital investigations of heterogeneity in lower cretaceous carbonate reservoir using fractal and multifractal concepts.

Characterization and prediction of reservoir heterogeneity are crucial for hydrocarbon production. This study applies the multifractal theory using both numerical and experimental data to characterize quantitatively the heterogeneity of pore structures in Lower Cretaceous limestone reservoir from the United Arab Emirates. Fractal dimensions calculated from three dimensional digital images showed good correlation (R2 = + 0.69) with experimental high-pressure mercury injection (HPMI) measurements. Moreover, both experimental and numerical fractal dimensions correlate well with experimental HPMI porosity measurements. Multifractal parameters such as the non-uniformity degree of the pore structures Δα, the asymmetry degree in the vertical axis Δf(α), the concentration of pore size distribution α0 and the asymmetry degree in the horizontal axis Rd estimated from digital and experimental data correlated well and revealed ability to quantitatively describe samples heterogeneity. The ranges of digital and experimental multifractal parameters provided the means to differentiate between homogeneous and heterogeneous samples.

The Design and Validation of a Self-Assessment Questionnaire of Critical Appraisal of Medical Literature Skills in Medical Students.

Introduction: Critical appraisal of medical literature is a challenging step of the evidence-based medicine practice. Many assessment questionnaires have been published in the literature, but they have mainly focused on all the evidence-based medicine practice process. The authors aimed to develop and validate a questionnaire assessing the critical appraisal skills of medical students from the same Faculty. Methods: The questionnaire was developed by item generation through a review of the literature and an expert committee. The questionnaire was validated in terms of content validity and construct validity. Fitness of data for analysis was checked through Kaiser-Meyer-Olkin (KMO) and Bartlett's sphericity. Construct validity was carried out using a principal axis exploratory factor analysis (EFA) with 'varimax' rotation to study the internal structure of the questionnaire and to extract the test major factors. The questionnaire was administrated to a cohort of under and postgraduate medical students (n=84) to evaluate the test reliability and select the best items. The reliability of the questionnaire was assessed by Cronbach's alpha coefficient to evaluate the internal consistency. The correlations between the self-confidence and satisfaction dimension score, the critical thinking dimension score, the learning style dimension score, the Fresno-adapted test scores and the total score were assessed using the Spearman's correlation test. Results: The questionnaire consisted of 31 items. A factorial analysis grouped the items into 3 dimensions that consisted of the self-confidence and satisfaction dimension, the critical thinking dimension and the learning style dimension. Cronbach's alpha accounted for 0.95, CI95% [0.9-1] for the entire questionnaire. The factor analysis explained 79.51% of the variance. The external validity assessment based on a Spearman's correlation study highlighted a weak correlation between the total scores and the critical thinking dimension and the self-perception and satisfaction dimension. Conclusion: In spite of the limitations of this study, mainly the small number of the students recruited, the questionnaire seems to measure with adequate reliability the competences of under and postgraduate medical students.

Green, zero-waste pathway to fabricate supported nanocatalysts and anti-kinetoplastid agents from sugarcane bagasse.

The conversion processes of sugarcane into direct-consumption sugar and juice are generating a tremendous amount of waste, the so-called sugarcane bagasse (SCB). Biochar preparation is among the practical solutions aiming to manage and valorize SCB into high added-value functional material (FM). Herein, we propose a novel zero-waste pathway to fabricate two FMs from one biomass. The SCB was first macerated and ultrasonicated to obtain the natural extract that served as bio-reducing medium. Then, the H2O/EtOH-extracted SCB was in-situ impregnated with a bimetallic solution of copper and silver nitrates. The process produced an intermediate composite (FM0), Ag/Cu-Ag+/Cu2+-loaded SCB which was carbonized to elaborate Ag/Cu-Biochar (FM1), free Ag/Cu nanoparticles (FM2) were obtained by microwaving the residual liquid waste. FM1 exhibited high catalytic activity for the total Fenton-like degradation of methylene blue. The experimental data followed the pseudo-first and the pseudo-second order rate laws with apparent degradation rate constants K1 45 10-3 min-1 and K2 0.115 g.mg-1.min-1, respectively. FM0, FM1 and FM2 were tested as new anti-kinetoplastid materials against two flagellated protozoans namely the Leishmania spp and the Trypanosoma cruzi. Notably, Ag/Cu (FM2) showed exceptional leishmanicidal and trypanocidal effects with IC50 values of 2.909 ± 0.051, 3.580 ± 0.016 and 3.020 ± 0.372 ppm for L.donovani, L. amazonensis and Trypanosoma cruzi, respectively. In this way, we combine green chemistry and agrowaste valorization in a full zero-waste process, to address the 3rd (indicator 3.3.5) and 6th (indicator 6.3.1) United Nations sustainable development goals, ″Good Health and Well-Being″ and ″Clean Water and Sanitation″.

Is critical thinking potential correlated to critical appraisal skills of medical literature?

INTRODUCTION: Critical appraisal of medical literature is a mandatory skill to practice evidence-based medicine. The relation between the critical appraisal skills and the critical thinking potential has been rarely assessed in the literature. AIM: To assess the relation of critical thinking potential to critical appraisal of medical literature competencies. Besides, they tried to highlight the variation of the critical thinking potential according to the students' level. METHODS: The authors conducted a mixed study associating a quantitative and a qualitative approach. The study included second year (SYME), third year (TYME) and postgraduate medical students (CME) and family doctors (FD) from the same faculty of medicine. All the students received the same active training focused on critical appraisal of medical literature. They were asked to fulfil a pre-requisite test and a self-assessment questionnaire before the training session and a final test after the training. The self-assessment questionnaire was conceived by an expert committee and assessed the main characteristics of critical thinking consisting of sensitivity to context, self-correction and search for criteria. Three months after the training, the students were interviewed using a semi-structured interview. The SPSS software 16.0 was used. RESULTS: In our study, 58.9% of the students presented a high critical thinking potential profile. Their scores varied according to their levels with better scores in SYME and FD and intermediate scores in TYME and CME. The pre-requisite test scores varied according to the critical thinking profile and the level. On the other hand, final test scores didn't differ according to the critical thinking profile or the level. CONCLUSION: Our results put emphasis on the variation of the critical thinking potential according to the students' levels. The better results of the SYME students in comparison to those in the TYME put emphasis on the necessity of changing curriculum in order to enhance the sensitivity and the inclination of the students.

A qualitative study about critical appraisal of medical literature learning among medical students.

INTRODUCTION: Skills in critical appraisal of medical literature are compulsory to achieve in medical practice. This step is the third step of the evidence-based medicine process whose main role is to bridge a gap between scientific evidence and practice. Acquiring skills in critical appraisal of the literature has been reported to be challenging for the trainees with different limits according to their levels, backgrounds or specialties. AIM: To assess the limits and factors influencing the practice of appraising literature of different students from the same faculty. This faculty included training of biostatistics and preventive medicine in the curriculum during the first 2 years of medical education without linking this learning to the evidence-based medicine practice. METHODS: The authors performed a qualitative study including volunteers who attended voluntarily the same training about critical appraisal of medical literature. The study was based on a satisfaction questionnaire fulfilled by all the participants at the end of the training and on an individual semi-structured interviews programmed 3 months after the training. The satisfaction questionnaire was rated by the authors. The authors proceeded also to a content analysis of the interviews following 3 steps: pre-analysis, treatment of the results, and interpretation. RESULTS: All the participants (95) fulfilled the questionnaire. The satisfaction's mean score revealed a general moderate satisfaction. Eleven students agreed to be interviewed: Five students from the third year of medical education, 2 students from the second year of medical education, 2 postgraduate students and 2 family doctors. The main themes discussed by the interviewees consisted of training organization, the assessment, the impact on research and the impact on the care process. CONCLUSION: To promote EBM learning, medical students first need to actively participate to interactive learning, introduced early and gradually into the curriculum and integrating all specialties including postgraduate students.

Spontaneous rupture of a left omental artery aneurysm treated by transcatheter arterial embolization: A case report.

Background: Omental artery aneurysms are extremely rare. Their rupture is related to high mortality and often treated by open surgery. We describe a case of a spontaneous rupture of a left omental artery aneurysm (OAA) that was successfully treated by transcatheter arterial embolization (TAE). Case presentation: A 68-year-old man presented with acute abdominal pain. On examination, he was hypotensive and tachycardic with a blood pressure of 90/50 mm Hg. He had diffuse abdominal distension and tenderness.An abdominal enhanced computed tomography scan (CT) showed a rupture of the left OAA responsible for moderate hemoperitoneum. We performed a successful TAE. Conclusion: Ruptured OAA causes high mortality. OAA represents the rarest form of splanchnic artery aneurysms. Interventional radiology permits to avoid unnecessary surgery.TAE is a safe procedure to control ruptured OAA. We highlight the importance of a rapid embolization if the patient is hemodynamically stable.

Risk stratifying patients with non-varicosic upper gastrointestinal hemorrhage using the Glasgow-Blatchford score: A case series of 91 patients.

Introduction: Non-variceal upper gastrointestinal hemorrhage (NVUGIH) often leads to systematic hospitalization and emergency endoscopy. However, in most cases, it does not constitute an immediate life threat. This study aimed to evaluate the Glasgow-Blatchford Score (GBS) in predicting the need for transfusions, and/or endoscopic or surgical treatments. Materials and methods: We conducted a retrospective monocentric study including 91 patients admitted in the general surgery department of the Hospital La Rabta Tunis for a NVUGIH.Univariate analysis was performed with the Student t-test for continuous variables and with the Chi-square test for categorical variables. For a cut-off point of 9, we calculated the sensibility and the sensitivity of the GBS to predict the need for transfusions and/or hemostatic procedure. Results: During the study period, 91 patients were admitted for NVUGIH. Sixty-one patients (67%) were transfused. Seven patients (7.7%) underwent emergency surgery and two patients had endoscopic hemostasis.The predictive factors for the use of transfusion and/or hemostasic treatments were: Age >50 years, ASA score, HR ≥ 90 bpm, pallor, Hb ≤ 9,5 g/dl, Urea ≥9,7 mmol/L.For a cut-off of 9 points of the GBS, sensitivity was 85.71% and specificity 92.86%. The positive predictive value was 96%. The negative predictive value was 74%. Conclusion: The main interest of the GBS lies in dispatching the patients between intensive care units for therapeutic intervention (if GBS> = 9) and ordinary hospitalization for surveillance (if GBS <9). It then makes it possible to rationalize the management of patients with digestive hemorrhage to identify those requiring hospital treatments (transfusion, endoscopic treatment, or surgery).

Simulation and Validation of Porosity and Permeability of Synthetic and Real Rock Models Using Three-Dimensional Printing and Digital Rock Physics.

A standard digital rock physics workflow aims to simulate petrophysical properties of rock samples using few millimeter size subsets scanned with X-ray microtomography at a high resolution of around 1 µm. The workflow is mainly based on image analysis and simulation procedures at a subset scale leading to potential uncertainties and errors that cannot be quantified experimentally. To overcome the gap between scales, we propose to integrate three-dimensional (3D) printing technology to generate enlarged subsets at a scale where experimental measurements are feasible to validate simulated results. In this study, we 3D printed synthetic and real samples and compared digital and experimental rock properties. The most challenging phase in the workflow consists of the difficulties encountered while cleaning the 3D printed samples to remove the support material. Results for subsets extracted from synthetic, sandstone, and carbonate samples showed good agreement between digital and experimental measurements for porosity values less than 12% and a range of permeability values between 100 and 2000 mD.

Surgical treatment for bleeding ileal varices: A case report.

INTRODUCTION AND IMPORTANCE: Bleeding from ileal varices is a rare and a life-threatening situation. Its management is difficult and includes endoscopic, surgical and interventional radiology treatment. Here we report a successful emergency surgery for bleeding ileal varices in a patient with cirrhosis due to autoimmune hepatitis. PRESENTATION OF A CASE: A 60-year-old woman was admitted for rectal bleeding. She had a history of autoimmune hepatitis. She was treated by endoscopic ligation for oesophageal varices. Eso-gastro-duodenal fibroscopy and colonoscopy failed to reveal the bleeding site. CT scan was then performed showing ileal varices due to a portocaval shunt, there was a communication between the superior mesenteric vein and the right internal iliac vein. As the embolization was not feasible and the bleeding did not stop, an exploratory laparotomy was performed showing two dilated veins on the surface of the ileal wall, communicating with the right internal iliac vein. We performed a ligation of the vessels. Postoperative course was uneventful. DISCUSSION: Ectopic varices are a rare case of gastrointestinal bleeding. Most of those patients have portal hypertension and liver cirrhosis. Diagnosing bleeding ileal varices is difficult because endoscopic examination can't always reveal the bleeding site. Interventional radiology is a good option for patients having bleeding ileal varices knowing that they often have advanced liver cirrhosis making them poor candidates for surgery. Haemostasis by endoscopy is often temporary and bleeding frequently recurs. Surgery should be considered if non-invasive treatments failed to ensure the haemostasis. CONCLUSION: Bleeding ileal varices is a rare situation. Interventional radiology and endoscopy can be good options. If not feasible, surgical treatment should not be delayed.

Management of an uncommon T-Cell lymphoma revealed by an anastomotic dehiscence in Crohn's disease: A case report.

INTRODUCTION AND IMPORTANCE: T-cell lymphoma degeneration in pancolic crohn's disease is scarce. It is mostly related to long-standing inflammatory bowel disease in patients under immunosuppressants. We reviewed the clinical, endoscopic, radiological and histologic data of the patient as well as the literature dealing with T-cell lymphoma arising from pancolic crohn's disease. CASE PRESENTATION: We describe in this paper an unusual case of a female young patient who underwent emergency surgery for per endoscopic perforation of the right colon while being under azathioprine. She had a subtotal colectomy with ileostomy and sigmoidostomy. After six months, we restored the digestive continuity through an ileorectal anastomosis. She was kept in remission on azathioprine. After one year, she presented with a pelvic abscess revealing a dehiscence of the ileorectal anastomosis leading to a surgical drainage and resection of the anastomosis associated with terminal ileostomy and closure of the rectal stump. Pathology examination revealed T cell lymphoma arising from the ileorectal anastomosis. DISCUSSION: Patients with long-standing IBD have an increased risk of developing colorectal cancer. The onset of a malignant lymphoma during the course of the CD is scarce. Some studies haves failed to identify crohn's disease as a risk factor of lymphoma whereas other ones have succeeded to. Immunosuppressants are reported to have carcinogenic effect. Rarely, lymphoma degeneration can be revealed by intestinal complications such as perforation like in our case. CONCLUSION: Many studies reported lymphoma degeneration of crohn's disease after long-term immunosuppressant therapy. However, rapid T-cell lymphoma degeneration revealed by anastomotic dehiscence in crohn's disease made our case unique and interesting.

Similarities and differences between tutoring and mentoring in medical education.

Supporting medical students involves two broad concepts that are often confused, namely tutoring and mentoring. These approaches, implemented in a heterogeneous way in medical schools, have been the topic of numerous publications. The objective of this update was therefore to define, then clarify, based on a literature review, the common characteristics and the differences between tutoring and mentoring in medical studies.

Pore-Scale Modeling of the Effect of Wettability on Two-Phase Flow Properties for Newtonian and Non-Newtonian Fluids.

The Darcy-scale properties of reservoir rocks, such as capillary pressure and relative permeability, are controlled by multiphase flow properties at the pore scale. In the present paper, we implement a volume of fluid (VOF) method coupled with a physically based dynamic contact angle to perform pore-scale simulation of two-phase flow within a porous medium. The numerical model is based on the resolution of the Navier-Stokes equations as well as a phase fraction equation incorporating a dynamic contact angle model with wetting hysteresis effect. After the model is validated for a single phase, a two-phase flow simulation is performed on both a Newtonian and a non-Newtonian fluid; the latter consists of a polymer solution displaying a shear-thinning power law viscosity. To investigate the effects of contact angle hysteresis and the non-Newtonian nature of the fluid, simulations of both drainage and imbibition are carried out in order to analyze water and oil saturation-particularly critical parameters such as initial water saturation (Swi) and residual oil saturation (Sor) are assessed in terms of wettability. Additionally, the model sensitivities to the consistency factor (χ), the flow behavior index (n), and the advancing and receding contact angles are tested. Interestingly, the model correctly retrieves the variation in Sor and wettability and predicts behavior over a wide range of contact angles that are difficult to probe experimentally.

Progress and impact of the publications of the Faculty of Medicine of Tunis: A 55 years study.

BACKGROUND: Over the past few years, efforts have been made to ensure that the teachers of the Faculty of Medicine of Tunis (FMT) cite their affiliation to the FMT and the University of Tunis El Manar in addition to their hospital institutions and their research structure in their publications. AIMS: In this study, we proposed to evaluate the FMT's membership in the publications of its teachers, to identify the different types of publications and to estimate the real number. METHODS: In this bibliometric cross-sectional study, we retrieved the FMT publications indexed in medline/pubmed database (1964-June2019). We have chosen the keywords corresponding to the publications of group1 (referenced FMT) and group2 (referenced FMT or annexed hospital-university institutions). Next, we calculated the rate of group1 on group2 and sorted the different types of items in group2. Finally, We estimated, after randomization, the actual number of FMT publications for a 99% confidence interval (99% CI). RESULTS: For groups 1 and 2, 1477 and 5194 publications were retrieved, respectively. The FMT membership rate averaged 28% ranging from 4% (1990-2010) to 44% (2011-2019). Of the FMT publications, 30% were free of charge and 55% were original articles. After a draw for 300 group2 publications, the estimated number of total FMT publications was between 4519 and 4934 for a 99% CI. CONCLUSIONS: It is essential to mention its affiliation to «the Faculty of Medicine of Tunis¼ and to «the University of Tunis El Manar¼ in order to improve the visibility and ranking of our two academic institutions.

Visible-light-driven CO2 reduction on dye-sensitized NiO photocathodes decorated with palladium nanoparticles.

The thin-layer-stacked dye-sensitized NiO photocathodes decorated with palladium nanoparticles (nPd) can be used for the visible-light-driven selective reduction of CO2, mostly to CO, at potentials starting as low as 0 V vs. RHE (compared to -0.6 V in the dark for electrocatalysis). The photosensitization of NiO by the organic dye P1, with a surface coverage of 1.5 × 10-8 mol cm-2, allows the hybrid material to absorb light in the 400-650 nm range. In addition, it improves the stability and the catalytic activity of the final material decorated with palladium nanoparticles (nPd). The resulting multi-layered-type photocathode operates according to the electron-transfer-cascade mechanism. On the one hand, the photosensitizer P1 plays a central role as it generates excited-state electrons and transfers them to nPd, thus producing the catalytically active hydride material PdH x . On the other hand, the dispersed nPd, absorb/adsorb hydrogen and accumulate electrons, thus easing the reductive electrocatalysis process by further driving the separation of charges at the photoelectrochemical interface. Surface analysis, morphology, and roughness have been assessed using SEM, EDS, and AFM imaging. Both conventional electrochemical and photoelectrochemical experiments have been performed to confirm the catalytic activity of hybrid photocathodes toward the CO2 reduction. The recorded cathodic photocurrents have been found to be dependent on the loading of Pd nanoparticles. A sufficient amount of loaded catalyst facilitates the electron transfer cascade, making the amount of dye grafted at the surface of the electrode the limiting parameter in catalysis. The formation of CO as the main reaction product is postulated, though the formation of traces of other small organic molecules (e.g. methanol) cannot be excluded.

Teaching of evidence-based medicine principles in Family medicine curriculum: a descriptive study.

BACKGROUND: Family medicine was considered officially and legally in early 2019 in Tunisia. In order to help general practitioners to fit with the new profile of family doctors, the faculty of medicine of Tunis launched an MBA curriculum in 2018. Teaching evidence-based-medicine (EBM) principals was planned in a one-day training and was divided into a morning lecture-based session and an afternoon work team session. AIM: To assess the acceptability of this training by the participants and to highlight the consequences of this tutoring on the research skills of the trainees. METHODS: This is a cross sectional, prospective and descriptive study including the trainees registered in the MBA curriculum. A web site was created and contained a pre-test. After the work team session, the participants were asked to fulfill a post test and a feed back form. RESULTS: 20 trainees participated to the training day. 17 participants agreed to fulfil the pre-test, the post test and the feed back form. The mean and the median scores of the pre-test were estimated respectively to 11.19 and 14/20. The mean score and the median of the post-tests scores were estimated respectively to 12.69, and 14/20. No significant statistical difference was observed between the pre and post test scores (p=0.2). The majority of the trainees were totally satisfied with the training program. 13/17 participants estimated their needs' scale in EBM practice to 4/5. CONCLUSION: Our results highlighted the acceptability of EBM teaching in family medicine curriculum. The absence of significant difference pre test and post test scores can be explained by the fact that all participants obtained their doctorate and were able to perform a critical appraisal of medical articles.

Assessment of the quality of the change of surgical wound dressings by the nursing staff in a university hospital of Tunis.

BACKGROUND: Infection of surgical wounds is the main cause of nosocomial infections. In the event of a defect in the care chain, in particular, during the change of the postoperative dressings, the infectious risk would be increased. AIM: To evaluate the gestures of change of dressing practiced by nurses of a university hospital department of surgery, in order to observe the insufficiencies. METHODS: We conducted a two-month-duration prospective, descriptive study having a qualitative approach, consisting of a protocol for observing nursing procedures carried out during the implementation of postoperative dressings in a university hospital surgery department from Tunis. A five-item observation grid was developed based on the nursing procedures that should be performed during dressing rehabilitation. RESULTS: This observation was made on 48 changes of dressings made by 13 nurses (eight women and five men). Inadequacies were noted during the preparation of the gesture, the preparation of the equipment, the execution of the act, the storage of the equipment and the transmission of the care to the rest of the nursing staff. CONCLUSION: The results of our study are consistent with a deficiency of the quality of repair of wounds by the nurses. They show a poor application of the rules of asepsis when repairing surgical wounds. This would be only partly due to inadequate staff training, as the majority of participating nurses were found to be familiar with the basics of the means and methods used to prevent infection of a wound. Other causes are lack of staff and work overload, lack of adequate material for the given care as well as lack of self-responsibility for its nursing practice. The resolution of these problems requires the setting up of an epidemiological surveillance system and the in-service training of the staff involved.

Encapsulating sclerosing peritonitis : two rare observations and literature review.

Sclerosing encapsulating peritonitis (SEP) is a rare and little known pathological entity. It is a chronic fibro-inflammatory disease of the peritoneum, resulting in the formation of a thick fibrous membrane, which engages partially or totally the abdominal organs. Clinical and radiological signs make the diagnosis difficult to establish preoperatively. We present two original observations of SEP illustrating different clinical presentations, diagnostic and therapeutic means. His diagnosis requires a peritoneal biopsy. The treatment is not completely established. Surgical treatment is difficult, involving viscerolysis and multiple incisions of the fibrous membrane. Despite the current progress in therapeutic management, the prognosis remains pejorative, with significant mortality.