Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Background: 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

On the strain to the onset of serrated flow in a magnesium alloy

Acoustic emission and transverse strain measurements are used to show that small strain bands appear superimposed onto the homogeneous deformation from the onset of gross plastic deformation. The strain carried by the bands gradually increases until they completely suppress the uniform deformation, at strains between 1.5% and 5%, depending on the strain rate. When this happens, macroscopic serrations are detected in the stress-strain curve. The results are discussed in terms of a current non-diffusional theory for the Portevin-Le Chatelier effect. (c) 2007 Acta Materialia Inc.. Published by Elsevier Ltd. All rights reserved

Influence of alumina and zirconia nanoparticles on mechanical properties and damping of magnesium

Magnesium polycrystals reinforced with 3 % (vol.) ZrO₂ nanoparticles and 3 % (vol.) AI2₂O₃ nanoparticles were deformed in tension at a constant strain rate at temperatures between 20 and 300°C. The yield stress of both materials decreases rapidly with temperature. The flow stress of Mg+AI2₂O₃ is higher than that of Mg+ZrO₂. Ductility of the composite with zirconia is substantially higher. The difference in the deformation behaviour of both composites is very probably caused by difference in bonding between matrix and ceramic nanoparticles.Поликристаллы магния, упрочненные 3% наночастиц ZrO₂ и 3% наночастиц AI₂O₃, были деформированы растяжением при постоянной скорости деформации в температурном интервале 20-300°C. Предел текучести обоих материалов быстро уменьшается с температурой. Напряжение текучести Mg+AI₂O₃ выше, чем у Mg+ZrO₂. Пластичность композита с цирконием существенно выше. Разница в поведении двух композитов при деформации является скорее всего результатом различия в прочности связи между матрицей и керамическими наночастицами.Полікристали магнію, зміцнені 3 % наночастинок ZrO₂ та 3 % наночастинок AI₂O₃, були деформовані розтягом при постійній швидкості деформації у температурному інтервалі 20-300°С. Границя текучості Mg+AI₂O₃ вища, ніж у Mg+ZrO₂. Пластичність композиту з цирконієм значно вища. Різниця в поведінці обох композитів при деформації є, найімовірніше, наслідком різниці міцності зв’язування матриці з керамічними наночастинками

Modeling of hardening and softening processes in Mg alloys

The tensile deformation behavior of a range of supersaturated Mg-Al solid solutions and an as-cast magnesium alloy AM60 has been studied. The Mg-Al alloys were tested at room temperature while the alloy AM60 was tested in the temperature range 293-573 K. The differences in the deformation behavior of the alloys is discussed in terms of hardening and softening processes. In order to identify which processes were active, the stress dependence of the strain-hardening coefficient was assessed using Lukac and Balik's model of hardening and softening. The analysis indicates that hardening involves solid solution hardening and interaction with forest dislocations and non-dislocation obstacles such as second phase particles. Cross slip is not a significant recovery process in the temperature range 293-423 K. At temperatures between 473 and 523 K the analysis suggests that softening is controlled by cross slip and climb of dislocations. At temperatures above 523 K softening seems to be controlled by dynamic recrystallisation. (C) 2004 Elsevier B.V. All rights reserved

Thermal stability of composites with the microcrystalline copper matrix

Translated from Czech (Report of the Dept. of Metal Physics, Charles Univ., Prague, 1998)SIGLEAvailable from British Library Document Supply Centre-DSC:9023.190(VR-Trans--8730)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Mechanical properties of Mg-Li-Al alloys reinforced by short saffil fibres

Translated from Czech (Kovove Mater. 2001 (1) p. 1-9)SIGLEAvailable from British Library Document Supply Centre-DSC:9023.190(10234)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Effect of thermal stress upon internal friction in Mg-Sc alloys

Translated from Czech (Kovove Mater. 1999 (5) 324-330)Available from British Library Document Supply Centre-DSC:9023.190(9710)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Deformation behaviour of alpha Zr and Zr-Sn alloys

Translated from Czech (Report of the Dept. of Metals Physics, Charles University, Prague (CZ), 1996)Available from British Library Document Supply Centre-DSC:9023.19000(VR-Trans--8399)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Internal friction in a Mg matrix composite after thermal cycling between room temperature and various upper temperatures

Translated from Czech (Report of the Dept. of Metal Physics, Charles univ., Prague, 1998)Available from British Library Document Supply Centre-DSC:9023.190(VR-Trans--8763)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Effect of thermal stress on internal friction in Mg-Sc alloys

Translated from Slovak (Kovove Mater. 1999 (5) 324-330)Available from British Library Document Supply Centre-DSC:9023.190(9735) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo