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- Ademuyiwa, Adesoji O., et al.
(author)
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Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
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In: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Journal article (peer-reviewed)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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| 2. |
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| 3. |
- Thomas, HS, et al.
(author)
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- 2019
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swepub:Mat__t
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| 4. |
- Aboelazayem, Omar, et al.
(author)
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Biodiesel production from high acid value waste cooking oil using supercritical methanol: Esterification kinetics of free fatty acids
- 2017
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Conference paper (peer-reviewed)abstract
- In this study, low quality waste cooking oil with high total acid value, has been used for biodiesel production. The main factors affecting the reaction has been analysed using Response Surface Methodology (RSM). A quadratic model representing the interrelationships between reaction variables and free fatty acids (FFA) conversion has been developed. Analysis of variance (ANOVA) has been used for checking the significance of the predicted model. Numerical optimisation concluded the optimum conditions for maximum conversion of FFA at methanol to oil (M:O) molar ratio, temperature, pressure and time of 35:1, 260oC, 110 bar and 16 minutes, respectively for 98% conversion. The predicted optimum conditions have been validated experimentally resulting in 97.7% conversion of FFA with 0.3% relative error. Kinetic and thermodynamic data of the esterification reaction has been studied resulting in pseudo first order reaction with reaction rate constant (k) of 0.00103 s-1, activation energy of 34.5 kJ/mol and Arrhenius constant of 1.26 s-1. Finally, a kinetic reaction has been simulated resulting in 97% conversion of FFA with 0.716% relative error from the experimental results.
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| 5. |
- Aboelazayem, Omar, et al.
(author)
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Biodiesel Production from High Acid Value Waste Cooking Oil Using Supercritical Methanol: Esterification Kinetics of Free Fatty Acids
- 2017
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In: European Biomass Conference and Exhibition Proceedings, 25thEUBCE, June 2017. - 2282-5819. - 9788889407172 ; , s. 1381-1387
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Conference paper (peer-reviewed)abstract
- In this study, low quality waste cooking oil (WCO) with high total acid value has been used for biodiesel production. The main factors affecting the reaction have been analysed using Response Surface Methodology (RSM). A quadratic model representing the interrelationships between reaction variables and free fatty acids (FFA) conversion has been developed. Analysis of variance (ANOVA) has been used to evaluate the significance of the predicted model. Numerical optimisation predicted the optimum conditions for maximum conversion of FFA at methanol to oil (M:O) molar ratio, temperature, pressure and time of 35:1, 260 °C, 110 bar and 16 min, respectively for 98 % conversion. The predicted optimum conditions have been validated experimentally resulting in 97.7 % conversion of FFA with 0.3 % relative error. Kinetic and thermodynamic data of the esterification reaction has been studied resulting in pseudo first-order reaction with reaction rate constant of 0.00103 s-1, activation energy of 34.5 kJ/mol and Arrhenius constant of 1.26 s-1. Finally, a kinetic reactor has been simulated resulting in 97 % conversion of FFA with 0.716 % relative error from the experimental results.
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| 6. |
- Bayomie, Omar S., et al.
(author)
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Exceeding Pinch limits by process configuration of an existing modern crude oil distillation unit – A case study from refining industry
- 2019
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 231, s. 1050-1058
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Journal article (peer-reviewed)abstract
- Crude Distillation Unit (CDU) represents significant challenge for retrofitting and energy optimisation as the most energy intensive consumer in a conventional crude oil refinery. Pinch Technology and its based-methodologies are found primary keys for decades to energy savings in refining industries for a range of common economic-based and environmental objectives or applications. Typical benefits in energy savings are reported within 20–40% of original designs. However, such savings are limited and questioned when modern refiners are dealt with. The current paper addresses the revamping of a modern refinery exhibiting an existing high energy efficiency (≈93%). This implies the maximum potential energy savings would only be 7% at current process conditions. The present research proposes an algorithm that tackles energy recovery of modern refiners, enabling additional savings beyond the energy targets set by the existing process. The algorithm starts by process simulation and validation against real plant data, followed by a network optimisation, e.g. stream splitting, to reach the energy targets set by Pinch Analysis. The energy targets are then moved to another lower level by performing potential process modifications to reduce the energy consumption further. Results showed that the current modern refinery unit could reach its energy targets by stream splitting modifications with hot energy savings of 2.69 MW. Process modifications resulted in additional energy savings of 31.3% beyond the current level of the existing plant alongside less than a year of payback period for estimated capital investment. An environmental assessment is performed, and comparable reductions were obtained with respect to greenhouse gas, with reduction in CO2 emissions by 45.1%. The proposed retrofit methodology is applicable to minimising energy consumptions of refiners including modern units to achieve energy levels beyond energy targets by new process modifications.
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| 8. |
- Calon, T. G. A., et al.
(author)
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Cytokine expression profile in the bone-anchored hearing system: 12-week results from a prospective randomized, controlled study
- 2018
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In: Clinical Implant Dentistry and Related Research. - : Wiley. - 1523-0899. ; 20:4, s. 606-616
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Journal article (peer-reviewed)abstract
- ObjectiveTo study the effect of implanting the percutaneous bone-anchored hearing system (BAHS) itself and inflammation of the peri-abutment skin warrant clarification. In this study, we aimed to acquire further insight into the immune responses related to BAHS surgery and peri-implant skin inflammation. Materials and MethodsDuring surgery and 12 weeks post-implantation, skin biopsies were obtained. If applicable, additional biopsies were taken during cases of inflammation. The mRNA expression of IL-1, IL-6, IL-8, TNF, IL-17, IL-10, TGF-ss, MIP-1, MMP-9, TIMP-1, COL11, VEGF-A, FGF-2 TLR-2, and TLR-4 was quantified using qRT-PCR. ResultsThirty-five patients agreed to the surgery and 12-week biopsy. Twenty-two patients had mRNA of sufficient quality for analysis. Ten were fitted with a BAHS using the minimally invasive Ponto surgery technique. Twelve were fitted with a BAHS using the linear incision technique with soft-tissue preservation. Five biopsies were obtained during episodes of inflammation. The post-implantation mRNA expression of IL-1 (P = .002), IL-8 (P = .003), MMP9 (P = .005), TIMP-1 (P= .002), and COL11 (P < .001) was significantly up-regulated. IL-6 (P = .009) and FGF-2 (P=.004) mRNA expression was significantly down-regulated after implantation. Within patients, no difference between post-implantation mRNA expression (at 12 weeks) and when inflammation was observed. Between patients, the expression of IL-1 (P = .015) and IL-17 (P = .02) was higher during cases of inflammation compared with patients who had no inflammation at 12-week follow-up. ConclusionsAs part of a randomized, prospective, clinical trial, the present study reports the molecular profile of selected cytokines in the soft tissue around BAHS. Within the limit of this study, the results showed that 12 weeks after BAHS implantation the gene expression of some inflammatory cytokines (IL-8 and IL-1) is still relatively high compared with the baseline, steady-state, expression. The up-regulation of anabolic (COL11) and tissue-remodeling (MMP-9 and TIMP1) genes indicates an ongoing remodeling process after 12 weeks of implantation. The results suggest that IL-1, IL-17, and TNF- may be interesting markers associated with inflammation.
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| 9. |
- Calon, Tim, et al.
(author)
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Multimodal analysis of the tissue response to a bone-anchored hearing implant. : 11.Calon TGA, Johansson ML, Omar O, Shah FA, Budding D, Trobos M, Thomsen P, Stokroos RJ, Palmquist
- 2019
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In: 2nd Politzer Society Meeting/2nd World Congress of Otology, 28 May - 1 June, 2019, Warsaw, Poland..
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Conference paper (other academic/artistic)
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