7 research outputs found
Hydraulic simulations to evaluate and predict design and operation of the Chashma Right Bank Canal
No full textIrrigation systems / Irrigation canals / Flow control / Velocity / Canal regulation techniques / Hydraulics / Simulation models / Design / Operations / Crop-based irrigation / Distributary canals / Water delivery / Policy / Protective irrigation / Water allocation / Water requirements / Sedimentation / Water distribution / Equity / Water conveyance / Pakistan / Chashma Right Bank Canal
Dual solutions of magnetized radiative flow of Casson Nanofluid over a stretching/shrinking cylinder: Stability analysis
No full textThe enhanced thermal efficiency exhibited by Casson nanofluids offers significant practical applications across various industrial and engineering sectors. This study focuses on the mathematical investigation of the steady magnetohydrodynamic (MHD) boundary layer flow of Casson nanofluid through a stretched/shrinking cylinder, taking into account the effects of suction and thermal radiation. The governing partial differential equations (PDEs) have been subjected to a similarity transformation, resulting in a set of nonlinear ordinary differential equations (ODEs). These ODEs were solved numerically utilizing the code of bvp4c in the software of Matlab which offers high accuracy (4th order). The employed nanofluid model incorporates the effects of Brownian motion and thermophoresis. The present study illustrates the graphical depictions of the impacts of different governing parameters, namely Hartmann (M) number, curvature (γ) parameter, Brownian motion (Nb) parameter, mass suction (S) parameter, thermal radiation (Rd) parameter, and thermophoresis (Nt) parameter, on heat transfer, flow, and mass transfer characteristics. Comprehensive determination and visual presentation of the coefficient of skin friction, local Nusselt number, and local Sherwood number were conducted for a range of estimates of applied parameters. Based on our examination, it has been determined that dual similarity solutions are present within a specific range of mass suction parameters. The relationship between the Casson parameter and various fluid dynamic properties, such as skin friction coefficient, heat transfer rate, and mass transfer rates, has been found to exhibit a decreasing trend. Furthermore, the stability analysis discovered that the first solution exhibits linear stability, whereas the second solution displays linear instability. Additionally, the motivation behind this study is to enhance industrial performance through the optimization of thermal power generation systems, thereby increasing their overall efficiency
Magnetized Casson SA-hybrid nanofluid flow over a permeable moving surface with stability analysis
No full textThis study employs the Tiwari and Das model to numerically evaluate the heat-transfer properties of a magnetized Casson sodium alginate-copper/alumina hybrid nanofluid flow over a permeable moving surface, taking into account the effects of viscous dissipation. Sodium alginate-alumina/copper hybrid nanofluids have garnered significant attention in modern society because of their potential uses in a variety of different industries. The key goal of the study is to examine the effect of the Casson parameter and copper solid volume fraction for skin friction coefficient and Nusselt number against velocity ratio parameter. Additionally, in the present study, velocity and temperature profiles for velocity ratio parameter, suction effect, magnetic parameter, Eckert number, and Prandtl number are also included. Using the bvp4c technique, the PDEs are converted into a set of non-linear ODEs with the use of suitable similarity variables. Dual approaches for controlling parameter using varied Casson fluid parameter and copper solid volume fraction quantities have been identified. Unique solutions, no solutions, and dual solutions exist in specific ranges of parameters. Consequently, beyond the critical values, no solution exists. The rate of heat transfer strengthened as the capacity of the Eckert number augmented. The temperature profile also diminished when the Prandtl number improved. The appearance of the boundary layer separation extension resulted from incorporating the copper solid volume fraction. Finally, stability analysis reveals that the first solution is stable, and the second solution is unstable
Clinical assessment of Renal Ischaemic Injury and the Role of Cryopreservation; Peritoneal Cooling an Non-Heart-Beating Donation and Topical Cooling for Laparoscopic Surgery
No full textAbstract
The project aims focussed on three main areas of study; ischaemic injury assessment, laparoscopic renal cryopreservation and peritoneal cooling for non-heart-beating organ donation. The effects of renal ischaemia represent significant challenges for transplantation and urological surgery in that with sufficient unchecked ischaemic duration, permanent loss of function is inevitable. Prior to consideration of novel approaches to ischaemic protection, aimed at producing improved graft quality for transplantation and an increased safe operating times for partial renal resections, deficiencies in the literature regarding the efficacy of viability testing were targeted. Techniques of ischaemic injury assessment are intended to allow identification of retrieved kidneys which are likely to have lost the potential for adequate function if transplanted. Such organs can then be discarded, thus improving outcomes and decreasing rates of primary non-function.
Results pertaining to ischaemic injury assessment provided support for protocols of viability assessment based on hypothermic machine perfusion. The effect of warm ischaemia on renal viability criteria has been successfully demonstrated in a large animal model, and novel approaches to the use of such assessments have been explored in order to maximise organ resource opportunities and utilisation.
The project has made an important contribution in the technical approach to laparoscopic partial nephrectomy and laparoscopic renal hypothermia. The studies involving the ‘Newcastle Laparoscopic Renal Cooling Device’ succeeded in achieving ‘proof of concept’ with demonstration of effective renal cooling and preservation..
Studies relating to preservation interventions in the porcine model of the uncontrolled NHBD have produced striking results. These results strongly suggest that uncontrolled NHBD centres employing cold in-situ perfusion approaches to preservation would be wise to consider supplementary techniques of organ cooling
Spatial variation in spawning timing for multi-species Acropora assemblages in the Red Sea
No full textSexual reproduction is a crucial process for reef building coral populations to maximize genetic diversity and recover from large scale disturbances. Mass spawning events by Acropora species represent critical opportunities for populations to persist, and a process that is increasingly exploited to actively restore degraded reefs. However, the timing and predictive capacity of coral spawning throughout the broad thermal and environmental regime of the Red Sea – a region also undergoing significant development and active reef restoration – remains patchy. We, therefore, conducted three parallel reef surveys in the central Red Sea (Al-Fahal Reef, Thuwal - Saudi Arabia) and the eastern (Shushah Island - Saudi Arabia) and western (Hurghada – Egypt) coast of the northern Red Sea. Surveys assessed the gravidity of gonads, spawning timing, alignment with the lunar cycle of 21 Acropora spp. (total n= 572 colonies) around the full moons of April and May 2023. Consistent with past observations, synchronous spawning was observed for Acropora spp. in both the central and northern Red Sea during April and May, respectively. Interestingly, corals spawned on the full moon in both Shushah and Thuwal sites. In contrast, corals in Hurghada were independent of the lunar cycle and spawned 7-9 nights before the full moon in May. By integrating our 2023 observations with the historical spawning events in Hurghada and Thuwal (2002-2022), we found that the deviation of spawning timing from the full moon day was correlated with absolute Sea Surface Temperature (SST) (earlier spawning before the full moon day, lower SST) and warming rate (earlier spawning, more rapid warming) in 6-weeks prior to spawning. As such, temperature pattern is likely one of the primary factors governing gamete release, among other factors, that likely influence spawning day within the lunar month. These correlations between SST metrics and spawning timing suggest a potential framework to predict future Acropora spp. spawning dates. Our observations demonstrate the importance of parallel efforts across borders to collect critical data needed to inform management strategies aimed at conserving and restoring coral reefs in this ecologically diverse region.The author(s) declare financial support was received for the research, authorship, and/or publication of this article. The conducted survey received separate funding at each site. Survey at KAUST was funded by the KAUST baseline fund to RP, while the survey at Shushah Island was supported through ongoing work of the KAUST Reefscape Restoration Initiative (KRRI). Furthermore, the work at Hurghada was funded by the Egyptian Environmental Affairs Agency (EEAA). EOO is partially funded by postdoctoral fellowship provided by Ocean Science and Solutions Applied Research Institute (OSSARI), Education, Research, and Innovation (ERI) Sector, NEOM, Tabuk, Saudi Arabia. This research was also supported in part by a grant #NGS-60324R-20 from the National Geographic Society provided to EOO.The authors express gratitude to James Geust, Jesscia Bouwmeester, and Sebastian Schmidt-Roach for their valuable contributions to the sampling design. Additionally, special thanks go to Barbara Ribeiro, Adam Barno, Yusuf El-khaled, Walter Rich (KAUST), and Sean Bull, Gareth Lloyd, Zac Forsman, and the KRRI Coastline dive team (Shushah) Ibrahim Alhamad, Wael Alsobhi, Ma’an Banjar, Mahmoud Gaber, Shadi Magdi, Ahmed Maghrabi, Adel Mustafa, Mohammed Saeed for their tireless support to the fieldwork through logistical support. The graphic design of Figure 3 was courtesy of Hend Nawwar (KAUST). The team is also thankful for all the support received from CMOR (Ramzi Aljahdali and Waleed Aljahdali) and the diving facility (Krasimir Todorov and Saeedullah Soomro) at KAUST to enable night dives. Also, we would like to thank Allen Coral Atlas for enabling visualization of coral reefs distribution along the Red Sea
Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study
No full textBackground: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030. Funding: Wellcome Trust
30-day Morbidity and Mortality after Cholecystectomy for Benign Gallbladder Disease (AMBROSE): A Prospective, International Collaborative Cohort Study
No full textObjective: This study aimed to assess 30-day morbidity and mortality rates following cholecystectomy for benign gallbladder disease and identify the factors associated with complications. Summary background data: Although cholecystectomy is common for benign gallbladder disease, there is a gap in the knowledge of the current practice and variations on a global level. Methods: A prospective, international, observational collaborative cohort study of consecutive patients undergoing cholecystectomy for benign gallbladder disease from participating hospitals in 57 countries between January 1 and June 30, 2022, was performed. Univariate and multivariate logistic regression models were used to identify preoperative and operative variables associated with 30-day postoperative outcomes. Results: Data of 21,706 surgical patients from 57 countries were included in the analysis. A total of 10,821 (49.9%), 4,263 (19.7%), and 6,622 (30.5%) cholecystectomies were performed in the elective, emergency, and delayed settings, respectively. Thirty-day postoperative complications were observed in 1,738 patients (8.0%), including mortality in 83 patients (0.4%). Bile leaks (Strasberg grade A) were reported in 278 (1.3%) patients and severe bile duct injuries (Strasberg grades B-E) were reported in 48 (0.2%) patients. Patient age, ASA physical status class, surgical setting, operative approach and Nassar operative difficulty grade were identified as the five predictors demonstrating the highest relative importance in predicting postoperative complications. Conclusion: This multinational observational collaborative cohort study presents a comprehensive report of the current practices and outcomes of cholecystectomy for benign gallbladder disease. Ongoing global collaborative evaluations and initiatives are needed to promote quality assurance and improvement in cholecystectomy
