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

Flexural behavior of basalt fiber reinforced concrete beams with recycled concrete coarse aggregates

This study investigates the effect of using recycled concrete aggregates (RCA) from construction and demolition (C&D) waste combined with basalt macro-fibers (BMF) on the flexural behavior and ultimate capacity of reinforced concrete (RC) beams experimentally and analytically. A total of 16 RC beam specimens were flexural tested to failure. The investigated parameters include the RCA replacement ratio and the volume fraction of the BMF. Furthermore, the experimental results were also compared against the existing analytical models and code-based equations for conventional concrete. The test results show that the flexural capacity of beams with the addition of BMF was improved. On the other hand, the use of RCA has no remarkable impact on the flexural strength of the tested beams. - 2018 Elsevier LtdThe authors show their gratitude to Qatar University for their financial support through the internal research grant QUUS-CENG-SPR14/15-21. The authors are grateful to the Construction Materials Co L.L.C. (Qatar Quarry Company) for providing the RCA. In addition, the support provided by ReforceTech, AS (Norway) is gratefully acknowledged

Flexural behavior of basalt fiber-reinforced concrete slab strips reinforced with BFRP and GFRP bars

This research investigates experimentally and analytically a novel one-way slab system reinforced with either basalt fiber-reinforced polymer (BFRP) or glass fiber-reinforced polymer (GFRP) longitudinal bars embedded in fiber-reinforced concrete (FRC) incorporating basalt macro-fibers (BMF). Twelve one-way concrete slab strips were prepared and tested to failure under four-point loading configuration. The investigated parameters included the type of fiber-reinforced polymer bars (BFRP and GFRP), the longitudinal reinforcement ratio (1.4 and 2.8, where is the balanced reinforcement ratio), and the volume fraction of the fibers added (0, 0.5, 1, and 2% per volume). The test results demonstrated the promise of BMF to enhance the flexural performance of the tested slab strips in terms of ductility and load-carrying capacities. The formulations of different available codes and design guidelines were used to predict the test results. Comparison between the experimental and predicted results showed the adequacy of the models to predict the flexural performance of the tested slab strips. The findings of this study demonstrated the potential of using the BMF as alternatives to conventional fibers in flexural concrete members.The authors show their gratitude to Qatar Foundation for their financial support through the UREP award No. [UREP18-162-2-065] from the Qatar National Research Fund .Scopu

Properties of fibre-reinforced concrete made with discarded materials

This research paper investigates the physical, chemical and mechanical properties of steel slag aggregates (SSA), gravel aggregates (GLA), natural gabbro aggregates (NGA), and the different fresh and hardened properties of concrete mixtures prepared using SSA, GLA and NGA. Furthermore, this paper presents the compression and flexural test results of different concrete mixtures made with SSA or NGA combined with different volume fractions of basalt macro-fibre (BMF). The investigated parameters included the type of coarse aggregates, the replacement of the recycled aggregates (0, 25, 50, 75 and 100%) and the volume fraction of BMF (0.25% and 1.0%). Test results have shown that replacing NGA with GLA reduces both the compressive and tensile strength of the concrete. However, concrete made with SSA tends to result in a higher compressive strength than that made with NGA. In addition, the test results showed a considerable improvement in mechanical concrete properties with increasing BMF volume fractions.This research work was funded by Slag Aggregate Producer, under Qatar University Research Grant No. QUEX-CENG-SAP-12/13-1 and Qatar University, under its Internal Research Grant No. QUUG-CENG-CAE-14/15-5. In addition, the support provided by ReforceTech (2016), AS (Norway) is gratefully acknowledged.Scopu

Green concrete for a circular economy: A review on sustainability, durability, and structural properties

A primary concern of conventional Portland cement concrete (PCC) is associated with the massive amount of global cement and natural coarse aggregates (NCA) consumption, which causes depletion of natural resources on the one hand and ecological problems on the other. As a result, the concept of green concrete (GC), by replacing cement with supplementary cementitious materials (SCMs) such as ground granulated blast furnace slag (GGBFS), fly ash (FA), silica fume (SF), and metakaolin (MK), or replacing NCA with recycled coarse aggregates, can play an essential role in addressing the environmental threat of PCC. Currently, there is a growing body of literature that emphasizes the importance of implementing GC in concrete applications. Therefore, this paper has conducted a systematic literature review through the peer-reviewed literature database Scopus. A total of 114 papers were reviewed that cover the following areas: (1) sustainability benefits of GC, (2) mechanical behavior of GC in terms of compressive strength, (3) durability properties of GC under several environmental exposures, (4) structural performance of GC in large-scale reinforced beams under shear and flexure, and (5) analytical investigation that compares the GC shear capacities of previously tested beams with major design codes and proposed models. Based on this review, the reader will be able to select the optimum replacement level of cement with one of the SCMs to achieve a certain concrete strength range that would suit a certain concrete application. Also, the analysis of durability performance revealed that the addition of SCMs is not recommended in concrete exposed to a higher temperature than 400?C. Moreover, combining GGBFS with FA in a concrete mix was noticed to be superior to PCC in terms of long-term resistance to sulfate attack. The single most striking observation to emerge from the data comparison of the experimentally tested beams with the available concrete shear design equations is that the beams having up to 70% of FA as a replacement to OPC or up to 100% of RCA as a replacement to NCA were conservatively predicted by the equations of Japan Society of Civil Engineers (JSCE-1997), the American Concrete Institute (ACI 318-19), and the Canadian Standards Association (CSA-A23.3-14).Scopu

Hybrid Split Hopkinson Pressure Bar to Identify Impulse-dependent Wave Characteristics of Viscoelastic Phononic Crystals

There has recently been a rising interest in the nonlinear wave transmission behavior of phononic crystals. However, experimental studies focusing on the nonlinear wave transmission behavior of phononic crystals have been predominantly performed on 1-D granular crystals using customized impact apparatus. In this study, we explore split Hopkinson pressure bar (SHPB) apparatus as a tool to study the nonlinear wave characteristics of a 1-D continuum viscoelastic phononic crystal. In order to resolve experimental challenges relating to signal-to-noise ratios and input impulse magnitudes, we propose a hybrid SHPB system composed of an aluminum input bar and a nylon output bar. For a considered viscoelastic phononic crystal, the application of the hybrid SHPB apparatus enabled us to observe some low transmission frequency zones, which were not identified from the linearly perturbed settings such as the analytical solution and the electrodynamic shaker tests. We further conducted a series of additional FE simulations to ensure the appearance of impulse-dependent low transmission frequency zones of the considered viscoelastic phononic crystal specimen. The additional sets of simulations evidently illustrate the impulse-dependent evolution of wave transmission coefficients, and demonstrate that the impulse-dependent wave transmission behavior can be experimentally investigated by adopting the hybrid SHPB apparatus. Thus, this study shows that the conventional SHPB apparatus can be employed effectively to study the emerging research field of nonlinear wave characteristics of phononic crystals.Acknowledgements The authors thank Qatar University Center for Advanced Materials facilitating the DMA tests of the considered silicon rubber. Thanks are also due to the support of the Center for Computational Research at the University at Buffalo (UB). The authors acknowledge the partial financial support through Qatar National Research Fund (QNRF) Grant No. NPRP8-1568-2-666.Scopu