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- Ademuyiwa, Adesoji O., et al.
(författare)
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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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Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Tidskriftsartikel (refereegranskat)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. |
- Thomas, HS, et al.
(författare)
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- 2019
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swepub:Mat__t
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| 5. |
- Zaki, Zaki I., et al.
(författare)
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Combustion synthesis of NbC/ZrO2 composites : Influence of Cr additives on the microstructure and mechanical properties
- 2021
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Ingår i: International Journal of Applied Ceramic Technology. - : John Wiley & Sons. - 1546-542X .- 1744-7402. ; 18:5, s. 1502-1509
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Tidskriftsartikel (refereegranskat)abstract
- Composites of NbC/ZrO2 reinforced with different weight ratios of Cr metal were prepared by dynamic compaction combustion from a blend of Nb2O5-Zr-Cr powders. Factors controlling the synthesis process, the microstructure and the mechanical properties of the samples, such as Cr wt% and the compression loads were studied. The samples were characterized by XRD, SEM, porosity and hardness measurements. The porosity value of sample with no additives was high and reached 31.6 vol%. A sudden decrease in the sample porosity to 2.4 vol % was noticed for sample containing 3.0 wt% of Cr. A high density sample with less than 2.0 vol % porosity and a maximum hardness of 1038 HV was produced using 5.0 wt% Cr under 300 MPa compression load. Detailed thermodynamic calculations for the effect of Cr additives on the physico-chemical properties of the system were introduced.
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| 6. |
- El-Sadek, M.H., et al.
(författare)
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Non-isothermal carbothermic reduction kinetics of mechanically activated ilmenite containing self-reducing mixtures
- 2018
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Ingår i: Journal of thermal analysis and calorimetry (Print). - : Springer. - 1388-6150 .- 1588-2926. ; 131:3, s. 2457-2465
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Tidskriftsartikel (refereegranskat)abstract
- Effect of mechanical activation on carbothermic reduction kinetics and mechanism of ilmenite concentrate containing self-reducing mixture has been investigated using a combination of thermogravimetry and X-ray diffraction. Thermogravimetric comparative study of mechanically activated and non-activated ilmenite concentrate containing self-reducing mixtures with C/O molar ratio of 1.5 was conducted non-isothermally. The samples were heated up to 1573 K at three different heating rates (10, 15, and 20 K min−1) under controlled atmosphere. The reduction mechanism of mechanically activated mixture was followed by X-ray diffraction analysis of arrested samples at different reduction extents. In addition, reaction kinetics was further investigated and corresponding kinetic parameters were estimated using isoconversional (model-free) and model-fitting (Coats–Redfern) methods.
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| 7. |
- Ellabban, Mohamed A., et al.
(författare)
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Virtual planning of the anterolateral thigh free flap for heel reconstruction
- 2022
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Ingår i: Microsurgery. - : WILEY. - 0738-1085 .- 1098-2752. ; 42:5, s. 460-469
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Tidskriftsartikel (refereegranskat)abstract
- Purpose three dimensional (3-D) virtual planning is an example of computer assisted surgery that improved management of composite tissue defects. However, converting the 3-D construct into two dimensional format is challenging. The purpose of this study was to assess 3-D virtual planning of complex heel defects for better optimized reconstruction. Patients and methods a prospective analysis of 10 patients [9 male and 1 female; mean age = 27.9 years] with post-traumatic heel defects was performed. Heel defects comprised types II (three patients) or III (seven patients) according to Hidalgo and Shaw and were managed using anterolateral thigh (ALT) free flap adopting 3-D virtual planning of the actual defect which was converted into a silicone two dimensional mold. The mean definitive size of the defects was 63.4 cm(3). Functional, aesthetic, and sensory evaluations of both donor and recipient sites were performed 1 year after surgery. Results Six patients received thinned ALT (mean size = 139 cm(3)) while four patients received musculofasciocutaneous ALT flap (mean size = 199 cm(3)). One flap exhibited partial skin flap necrosis. Another flap was salvaged after re-exploration secondary to venous congestion. The mean follow-up was 20.2 months. The Maryland foot score showed 4 excellent, 5 good, and 1 fair cases. The mean American Orthopedic Foot and Ankle hind foot scoring was 76.3 (range: 69-86). All patients regained their walking capability. Conclusions 3-D virtual planning of complex heel defects facilitates covering non-elliptical defects while harvesting a conventional elliptical flap with providing satisfactory functional outcomes and near-normal contour, volume, and sensibility.
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| 8. |
- Haenssle, H A, et al.
(författare)
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Man against machine: diagnostic performance of a deep learning convolutional neural network for dermoscopic melanoma recognition in comparison to 58 dermatologists.
- 2018
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Ingår i: Annals of Oncology. - : Elsevier BV. - 1569-8041 .- 0923-7534. ; 29:8, s. 1836-1842
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Tidskriftsartikel (refereegranskat)abstract
- Deep learning convolutional neural networks (CNN) may facilitate melanoma detection, but data comparing a CNN's diagnostic performance to larger groups of dermatologists are lacking.Google's Inception v4 CNN architecture was trained and validated using dermoscopic images and corresponding diagnoses. In a comparative cross-sectional reader study a 100-image test-set was used (level-I: dermoscopy only; level-II: dermoscopy plus clinical information and images). Main outcome measures were sensitivity, specificity and area under the curve (AUC) of receiver operating characteristics (ROC) for diagnostic classification (dichotomous) of lesions by the CNN versus an international group of 58 dermatologists during level-I or -II of the reader study. Secondary end points included the dermatologists' diagnostic performance in their management decisions and differences in the diagnostic performance of dermatologists during level-I and -II of the reader study. Additionally, the CNN's performance was compared with the top-five algorithms of the 2016 International Symposium on Biomedical Imaging (ISBI) challenge.In level-I dermatologists achieved a mean (±standard deviation) sensitivity and specificity for lesion classification of 86.6% (±9.3%) and 71.3% (±11.2%), respectively. More clinical information (level-II) improved the sensitivity to 88.9% (±9.6%, P=0.19) and specificity to 75.7% (±11.7%, P<0.05). The CNN ROC curve revealed a higher specificity of 82.5% when compared with dermatologists in level-I (71.3%, P<0.01) and level-II (75.7%, P<0.01) at their sensitivities of 86.6% and 88.9%, respectively. The CNN ROC AUC was greater than the mean ROC area of dermatologists (0.86 versus 0.79, P<0.01). The CNN scored results close to the top three algorithms of the ISBI 2016 challenge.For the first time we compared a CNN's diagnostic performance with a large international group of 58 dermatologists, including 30 experts. Most dermatologists were outperformed by the CNN. Irrespective of any physicians' experience, they may benefit from assistance by a CNN's image classification.This study was registered at the German Clinical Trial Register (DRKS-Study-ID: DRKS00013570; https://www.drks.de/drks_web/).
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| 9. |
- Zaki, Zaki I., et al.
(författare)
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Synthesis of Vanadium Carbide by Mechanical Activation Assisted Carbothermic Reduction
- 2020
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Ingår i: Materials. - : MDPI. - 1996-1944. ; 13:19
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Tidskriftsartikel (refereegranskat)abstract
- Vanadium carbide is known, for its hardness and other unique properties, as a refractory material. The synthesis of vanadium carbide is always associated with the utilization of expensive active metals, such as aluminum, calcium and magnesium, as a reducing agent to extract the vanadium metal from its corresponding oxide, followed by carbidization. The carbidization of reduced vanadium requires a complicated process and elevated temperature. Mechanical activation to synthesize vanadium carbide from its corresponding oxide and carbon source represents a promising, straightforward and less energy-intensive route. In the present study, vanadium carbide is synthesized by the carbothermic reduction of a mechanically activated mixture of V2O5 and carbon black as reducing agents without any additives. The reduction process is monitored by means of thermogravimetric analysis. The reduction products are characterized by X-ray diffraction and field emission scanning electron microscope. It is found that V8C7 with an average crystallite size of 88 nm can be synthesized from a V2O5-C mixture after milling for 15 h and further heating at 1050 °C for 1 h in an inert atmosphere.
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