Colour in visualisation for computational fluid dynamics

Colour is used in computational fluid dynamic (CFD) simulations in two key ways. First it is used to visualise the geometry and allow the engineers to be confident that the model constructed is a good representation of the engineering situation. Once an analysis has been completed, colour is used in post-processing the data from the simulations to illustrate the complex fluid mechanic phenomena under investigation. This paper describes these two uses of colour and provides some examples to illustrate the key visualisation approaches used in CFD

Evaluation of the preoperative administration of sildenafil on operative and early postoperative outcome after mitral valve replacement in patients with pulmonary hypertension

Background: Mitral valve diseases are commonly associated with pulmonary hypertension. The aim of this study was to evaluate the effect of preoperative administration of sildenafil on the outcome after mitral valve replacement in patients with pulmonary hypertension. Methods: This prospective randomized study was carried out on 67 patients who had a mitral valve replacement and associated high systolic pulmonary artery pressure more than 50 mmHg. Patients were randomized into three groups: group A (n= 20) received preoperative sildenafil for one week, group B (n=22) received sildenafil for one month, and group C (n= 25) did not receive sildenafil. All patients had transthoracic echocardiography preoperatively, one week and one month postoperatively. Results: There was no difference in preoperative and operative variables among groups. Dobutamine support was required in 15 patients (60%) in group C vs. 6 patients (30%) in group A and 5 patients (22.5%) in group B (p= 0.012). Duration of mechanical ventilation was significantly longer in group C (389.2 ± 48.79 minutes) compared to group A and B (295.5 ± 17.01 and 281.4 ± 39.44 minutes, respectively, p<0.001). ICU stay was longer in group C (61.72 ± 13.69 hours) compared to groups A and B (53.55 ± 14.49 and 45.64 ± 13.43 hours, respectively, p=0001). The hospital stay was longer in group C (8.0 ± 1.80 days) compared to group A and B (6.05 ± 0.94 and 6.27 ± 1.24 days, respectively; p< 0.001). The transthoracic echocardiographic study one month after the operation showed that pulmonary artery systolic pressure significantly lower in groups A and B (28.30 ± 3.3 and 28.2 ± 4.98 mmHg, respectively) compared to group C (43.12 ± 4.99 mmHg) (p <0.001). There was no statistically significant difference between groups A and B regarding PASP after five days  (p= 0.287) or one month (p= 0.939). Conclusion: We found that preoperative administration of oral sildenafil in patients with pulmonary hypertension undergoing mitral valve replacement may reduce pulmonary hypertension postoperatively. We could not find a difference in the administration of sildenafil for either one week or one month preoperatively

Coarse-resolution Ecology of Etiological Agent, Vector, and Reservoirs of Zoonotic Cutaneous Leishmaniasis in Libya

Cutaneous leishmaniasis ranks among the tropical diseases least known and most neglected in Libya. World Health Organization reports recognized associations of Phlebotomus papatasi, Psammomys obesus, and Meriones spp., with transmission of zoonotic cutaneous leishmaniasis (ZCL; caused by Leishmania major) across Libya. Here, we map risk of ZCL infection based on occurrence records of L. major, P. papatasi, and four potential animal reservoirs (Meriones libycus, Meriones shawi, Psammomys obesus, and Gerbillus gerbillus). Ecological niche models identified limited risk areas for ZCL across the northern coast of the country; most species associated with ZCL transmission were confined to this same region, but some had ranges extending to central Libya. All ENM predictions were significant based on partial ROC tests. As a further evaluation of L. major ENM predictions, we compared predictions with 98 additional independent records provided by the Libyan National Centre for Disease Control (NCDC); all of these records fell inside the belt predicted as suitable for ZCL. We tested ecological niche similarity among vector, parasite, and reservoir species and could not reject any null hypotheses of niche similarity. Finally, we tested among possible combinations of vector and reservoir that could predict all recent human ZCL cases reported by NCDC; only three combinations could anticipate the distribution of human cases across the country

Video-Assisted Thoracoscopic Surgery versus Open Decortication in Chronic Pleural Empyema

Background: The role of video-assisted thoracoscopic surgery (VATS) for managing organized empyema is still limited. This study compared VATS versus open decortication in patients with chronic pleural empyema. Methods: This randomized controlled trial included 58 patients with stage III empyema. Patients were divided into two groups. Group A (n= 30) included patients who had decortication through an open thoracotomy, and Group B (n= 28) included VATS decortication patients. Two patients in the VATS group were converted to the open approach and were excluded from the analysis. Results: The mean age in Group A was 48.23 ± 8.44 years and 49.79 ± 7.85 years Group B (p= 0.47). There were 16 males (53.3%) in Group A and 15 (63.6%) in Group B (p= 0.99). The operative time was 336.0 ± 67.60 min in Group A and 291.07 ± 56.66 min in Group B (p= 0.01). There was no difference in intraoperative complications between groups. Postoperative hospital stay (p= 0.23) and ICU admission (p= 0.24) did not differ between groups. In Group A, the pain scale was 8 (6- 8), and it was 4 (2- 4) in Group B (p˂ 0.001). No difference was recorded in the postoperative complications between groups. Conclusion:  The outcomes of VATS in managing stage III empyema are comparable to the open approach. VATS has the advantage of lower postoperative pain. VATS could be an alternative to open decortication in patients with stage III pleural empyema

Partial versus Full Sternotomy for Aortic Valve Replacement

Background: Minimal invasive approaches are used more frequently for aortic valve replacement (AVR). This study aimed to compare the outcomes of both minimally invasive upper mini-sternotomy and full sternotomy for AVR. Methods: 100 patients with isolated aortic valve disease were enrolled in this prospective observational study. We grouped the patients according to the technique, group A (n=40) underwent upper J-shaped mini-sternotomy, and group B (n=60) underwent full sternotomy. Study endpoints were operative times and pain score. Results: The mean age of the patients was 46.4±10.1 years. There was no difference in preoperative data between both groups. There was a significant difference in aortic cross-clamp time (87.2± 8.6 vs. 59.2± 6.6  min in group A and B, respectively, p= 0.001), and total bypass time (115.1± 9.2 vs. 75.3± 4.3 min in group A and B, respectively, p= 0.001) between both groups. The total operative time was 341±11.7 and 196.1±18.4 min in groups A and B, respectively (p= 0.001). The ICU stay was 29.4±8.2 hours in group A and 41.2±13.3 hours in group B (p= 0.001). Patients who had mini-sternotomy had lower pain (p= 0.001) and better patient satisfaction score (p< 0.001). Conclusion: J-shaped upper mini-sternotomy is a safe and effective strategy for aortic valve replacement. The procedure may be associated with decreased pain and comparable morbidity to the conventional approach

Sternal healing after bilateral internal mammary arteries use for Coronary artery bypass grafting in diabetic Patients; short-term results

Background:  Bilateral internal mammary artery (BIMA) use may improve long-term outcomes after coronary artery bypass grafting (CABG); however, the risk of infection is high.   Skeletonization of the internal mammary may decrease the risk of infection, especially in patients with diabetes. Our study aimed at evaluation of sternal healing in diabetic patients with different techniques of bilateral internal mammary artery harvesting. Methods: This prospective randomized study included 200 diabetic patients who underwent CABG using BIMA between 2017 and 2019. We divided patients into two groups; Group A had skeletonization of both internal mammary arteries, and Group B had pedicled left mammary and skeletonized right mammary. Patients were observed for three months, post-operatively for any sternal wound problems. Results: There was no significant difference regarding the baseline variables. Type I diabetes mellitus was present in 25% in group A (n= 24) and 13.64% in group B (n= 12) (p= 0.324). There was no difference in harvest time between groups (83 ±4 vs. 81 ±3 minutes in group A vs. B, respectively. P= 0.1). The mean number of grafts was 3± 0.5 in Group A and 3± 0.6 in Group B (p= 0.8). Postoperative drainage was 402.9 ± 174.1 ml in Group A vs. 387.2 ± 153.6 ml in Group B (p= 0.474). The duration of ICU stay did not differ significantly between groups (2± 0.7 in Group A vs. 2± 0.5 in Group B; p= 0.8). Deep sternal wound infection occurred in 4.17% in group A (n= 4) and 4.55% in group B (n= 4) (p= 0.705). Superficial wound infection occurred in eight patients in group A (8.33%) and eight patients in group B (9.1%) (p= 0.59). No patient had sternal dehiscence in group A vs. four patients in group B (4.55%) (p= 0.39). Conclusion: We did not find differences between bilateral mammary artery harvest with skeletonization of both arteries versus skeletonization of the right mammary only on sternal healing nor wound infection in diabetic patients undergoing CABG. A larger study is recommended

Study of process intensification Higee technology applied to the absorption

Treballs Finals de Grau d'Enginyeria Química, Facultat de Química, Universitat de Barcelona, Curs: 2015-2016, Tutor: Jose Maria Gutiérrez GonzálezHigee technology or High-gravity Technology has been widely studied for the intensification of industrial processes such as absorption, desorption, distillation, extraction, among others, in order to find and improve the benefits compared to conventional methods. According to Documents about Best Available Techniques (BREFs), Higee technology is emerging as an alternative to the methods used so far. This work studies Higee technology improvements applied to the absorption process compared to conventional packed columns. The absorption is mainly used to remove pollutant components of a gas stream to avoid leaks outside and/or to recover some component that the stream could contain for production purposes. To achieve the goals of this project, a bibliographic search of Higee technology, studied by different authors, has been performed. In this research, the focus is on the modifications made in recent years in order to show the advantages of this technology compared to the conventional one. After this research, the design of a conventional absorption column and Rotating Packed Bed have been studied in order to make a comparison among the design results and a comparison of these with those obtained experimentally by the different authors. From these studies the main conclusion is that the use of Higee technology get a huge reduction in the volume of the device and it is also possible to use smaller amounts of absorbent liquid. However, Higee technology presents some disadvantages over conventional technology because it is necessary that the absorbent liquid be subjected to a centrifugal force, so this will require greater energy. All these changes make the design more complex and the device suffers a faster wear due to continuous movement and, consequently, it increases the economic cost. Thus, based on studies performed so far, replacing the conventional absorption column for Higee technology is not recommendable. However, it should be further investigated because it has potential to get better results in comparison with conventional processes, either applied in the process studied in this work or applied to another types of processes

May Coronary Artery Bypass Grafting Affect Native Coronary Atherosclerosis progression?

Background: Coronary artery bypass grafting (CABG) continues to be the best standard in the management of severe coronary artery disease (CAD), providing good symptom management and life extension. Although CABG was first performed by reversed saphenous veins (SVGs), surgeons have increasingly adopted arterial conduits because of their longer-term patency and resistance to atherosclerosis. CABG's efficacy may potentially be affected by the extension of atherosclerosis in the native coronary arteries. Few researches have investigated the long-term angiographic disease progression of native coronary arteries after surgical revascularization, or the variables that may impact this progression. Proximal native disease progression was presented to be two to six times more common than distal disease progression, with greater rates of progression in coronaries bypassed by SVGs than arterial grafts. The goal of this research was to determine influence of CABG on the extension of native coronaries atherosclerosis. Methods: This prospective study was established on 25 patients who were diagnosed to have ischemic heart disease in cardiothoracic surgery department in Faculty of Medicine Menoufia University. Results: The study showed that according to the risk factors among the studied cases, smoking was (60%), Dyslipidemia was (32%), HTN was (32%) and Diabetes was (32). According to grafts in proximal lesions, there was progression of atherosclerosis up to total occlusion, but in Distal lesions, there was significant regression of atherosclerosis. As result, there was statistically significant difference between proximal with distal lesions. Also, study showed that there was a significant difference between left system (LAD, D, OM) in comparison with right system (PDA) regarding distal lesion. Our results showed that univariate logistic regression analysis for progression in distal lesion regarding Dyslipidemia and Diabetes. Conclusion: Progression of disease is more evident in coronary segment proximal to anastomosis, while regression of disease is more evident in coronary segment distal to anastomosis with statistically significant difference between them, also the risk of disease progression post CABG was found to be multifactorial, as certain risk factors can affect progression of the disease as Diabetes mellitus and dyslipidemia that were of statistically significance