Experimental Investigation of Additive Manufacturing of Continuous Carbon Fiber Composites with Multifunctional Electro-Tensile Properties

Manufacturing processes for monofunctional and multifunctional materials vary depending on the design optimization. Multifunctional continuous carbon fiber composites provide great potential in achieving coupled structural and electrical properties for their applications in aircraft, unmanned aircraft systems, and spacecraft. Proper optimization of tensile and electrical properties offers benefits early in the design and continuous operational safety phases to obtain coupled multifunctional properties. In this paper, fused filament fabrication additive manufacturing (AM) technique was used to fabricate continuous carbon fiber solid laminated composites test coupons. The proposed new method characterizes the electrical conductivity’s coupled effects on the tensile properties, including the failure loads and modes. This paper addresses a novel way of integrating electrical function into the composites that significantly reduce weight, potentially replacing the bulky electrical wires. Tensile and electrical conductivity tests were concurrently conducted on coupons, and the results were plotted and tabulated. The results showed the multifunctional properties of the maximum ultimate tensile strength of 392 MPa with the maximum tensile load of 8907 N, and resistance of 37.5 G·Ω. The average values for ultimate tensile strength and maximum load were 371 MPa and 8459 N, respectively.     

New-onset diabetes in COVID-19 and clinical outcomes: A systematic review and meta-analysis

BACKGROUNDDiabetes mellitus (DM) is associated with adverse clinical outcomes and high mortality in patients with coronavirus disease 2019 (COVID-19). The relationship between diabetes and COVID-19 is known to be bidirectional.AIMTo analyze the rate of new-onset diabetes in COVID-19 patients and compare the clinical outcomes of new-onset diabetes, pre-existing diabetes, hyperglycemic, and non-diabetes among COVID-19 patients.METHODSWe used the Meta-analysis of Observational Studies in Epidemiology statement for the present meta-analysis. Online databases were searched for all peer-reviewed articles published until November 6, 2020. Articles were screened using Covidence and data extracted. Further analysis was done using comprehensive meta-analysis. Among the 128 studies detected after thorough database searching, seven were included in the quantitative analysis. The proportion was reported with 95% confidence interval (CI) and heterogeneity was assessed using I².RESULTSAnalysis showed that 19.70% (CI: 10.93-32.91) of COVID-19 patients had associated DM, and 25.23% (CI: 19.07-32.58) had associated hyperglycemia. The overall mortality rate was 15.36% (CI: 12.57-18.68) of all COVID-19 cases, irrespective of their DM status. The mortality rate was 9.26% among non-diabetic patients, 10.59% among patients with COVID-19 associated hyperglycemia, 16.03% among known DM patients, and 24.96% among COVID-19 associated DM patients. The overall occurrence of adverse events was 20.52% (CI: 14.21-28.70) among COVID-19 patients in the included studies, 15.29% among non-diabetic patients, 20.41% among patients with COVID-19 associated hyperglycemia, 20.69% among known DM patients, and 45.85% among new-onset DM. Meta-regression showed an increasing rate of mortality among new hyperglycemic patients, known diabetics, and new-onset DM patients in comparison to those without diabetes.CONCLUSIONA significantly higher rate of new onset DM and hyperglycemia was observed. Higher mortality rates and adverse events were seen in patients with new-onset DM and hyperglycemia than in the non-diabetic population.     

Diagnostic accuracy of glycogen phosphorylase BB for myocardial infarction: A systematic review and meta‐analysis

PurposeWe tried to investigate the diagnostic accuracy of glycogen phosphorylase BB as a cardiac marker for myocardial infarction.MethodsWe searched through different electronic databases (PubMed, Google‐scholar, Embase, and Cochrane Library) to locate relevant articles. Studies, with sufficient data to reconstruct a 2 × 2 contingency table, met our inclusion criteria were included. Three reviewers independently screened the articles. Discrepancies were resolved by other reviewers. Unpublished data were requested from the authors of the study via email. Subsequently, data extraction was done using a standardized form and quality assessment of studies using the QUADAS‐2 tool. Meta‐analysis was done using a bivariate model using R software.ResultsFourteen studies were selected for the final evaluation, which yielded the summary points: pooled sensitivity 87.77% (77.52%–93.72%, I² = 86%), pooled specificity 88.45% (75.59%–94.99%, I² = 88%), pooled DOR 49.37(14.53–167.72, I² = 89%), and AUC of SROC was 0.923. The lambda value of the HSROC curve was 3.670. The Fagan plot showed that GPBB increases the pretest probability of myocardial infarction from 46% to 81% when positive, and it lowers the same probability to 12% when negative.ConclusionWith these results, we can conclude that GPBB has modest accuracy in screening myocardial infarction, but the limitations of the study warrant further high‐quality studies to confirm its usefulness in predicting myocardial infarction (MI).     

Electronic,mechanical, optical and piezoelectric properties of glass-like sodium silicate (Na2SiO3) under compressive pressure

The structural, mechanical, electronic, optical and piezoelectric properties of Na₂SiO₃ are studied under varying compressive unidirectional pressure (0–50 GPa with a difference of 10 GPa) using density functional theory (DFT). The calculated structural properties agree well with previously reported results. At 12 GPa, our calculation shows a structural phase transition from orthorhombic Cmc2₁ to triclinic P1. The mechanical profile of Na₂SiO₃ structures under different compressive unidirectional pressures are analysed by calculating the elastic moduli, Poisson’s ratio and eigenvalues of stiffness matrix. Our study shows the mechanical stability of the system up to a pressure of 40 GPa. Herein, we have obtained an indirect band gap of 2.97 eV at 0 GPa. Between 0–50 GPa, the band gaps are within the range 2.62 to 3.46 eV. The system in our study possesses a wide band gap and high optical absorption in the UV-Vis range of electromagnetic radiation. The calculated static refractive indices η^x,y,z(0) are close to unity suggesting its transparency. For piezoelectric properties, we have reported the total Cartesian polarization. Our calculations have revealed that Na₂SiO₃ is a promising candidate for optoelectronic devices while its application in ferroelectric and piezoelectric devices could be improved with further research.

Structural phase transitionoccurs from space group Cmc2₁ to C11 at 12 GPA under compressive unidirectional pressure in Na₂SiO₃.     

Post-transplant lymphoproliferative disorders (PTLD)-from clinical to metabolic profiles-a single center experience and review of literature

Post-transplant lymphoproliferative disorders (PTLD) are among the most serious complications after solid organ transplantation (SOT). Monomorphic diffuse large B-cell lymphoma (DLBCL) is the most common subtype of PTLD. Historically, outcomes of PTLD have been poor with high mortality rates and allograft loss, although this has improved in the last 10 years. Most of our understanding about PTLD DLBCL is extrapolated from studies in non-PTLD DLBCL, and while several clinical factors have been identified and validated for predicting non-PTLD DLBCL outcomes, the molecular profile of PTLD DLBCL has not yet been characterized. Compartment-specific metabolic reprograming has been described in non-PTLD DLBCL with a lactate uptake metabolic phenotype with high monocarboxylate transporter 1 (MCT1) expression associated with worse outcomes. The aim of our study was to compare the outcomes of PTLD in our transplant center to historic cohorts, as well as study a subgroup of our PTLD DLBCL tumors and compare metabolic profiles with non-PTLD DLBCL. We performed a retrospective single institution study of all adult patients who underwent a SOT between the years 1992-2018, who were later diagnosed with PTLD. All available clinical information was extracted from the patients’ medical records. Tumor metabolic markers were studied in a subgroup of PTLD DLBCL and compared to a group of non-PTLD DLBCL. Thirty patients were diagnosed with PTLD following SOT in our center. Median time from SOT to PTLD diagnosis was 62.8 months (IQR 7.6; 134.4), with 37% of patients diagnosed with early PTLD, and 63% with late PTLD. The most common PTLD subtype was DLBCL. Most patients were treated with reduction of their immunosuppression (RIS) including a group who were switched from calcineurin inhibitor (CNI) to mTOR inhibitor based IS, in conjunction with standard anti-lymphoma chemoimmunotherapy. Progression free survival of the PTLD DLBCL cohort was calculated at 86% at 1 year, and 77% at 3 and 5-years, with overall survival of 86% at 1 and 3-years, and 75% at 5 years. Death censored allograft survival in the kidney cohort was 100% at 1 year, and 93% at 3, 5 and 10 years. MCT1 H scores were significantly higher in a subset of the non-PTLD DLBCL patients than in a PTLD DLBCL cohort. Our data is concordant with improved PTLD outcomes in the last 10 years. mTOR inhibitors could be an alternative to CNI as a RIS strategy. Finally, PTLD DLBCL may have a distinct metabolic profile with reduced MCT1 expression compared to non-PTLD DLBCL, but further studies are needed to corroborate our limited cohort findings and to determine if a specific metabolic profile is associated with outcomes.     

Community-based interventions for diarrhoeal diseases and acute respiratory infections in Nepal

Problem

Acute diarrhoeal diseases and acute respiratory infections (ARIs) are the most common causes of child mortality worldwide. Safe, effective and inexpensive solutions are available for prevention and control, but they do not reach needy communities.

Approach

Interventions based on research were designed to train and engage community health volunteers (CHVs) to implement a community-based control programme in Nepal. With the advent of the Integrated Management of Childhood Illnesses (IMCI) strategy, this programme subsequently emerged as a community-based IMCI but retained its mainstream activities. We reviewed and analysed policy decisions and programme development, implementation and expansion.

Local setting

Severe resource constraints and difficult terrain limit access to health-care facilities in many parts of Nepal.

Relevant changes

In districts with interventions, more cases of acute diarrhoea and of ARIs (including pneumonia) were reported. The proportion of diarrhoea cases with dehydration and the proportion of ARI cases with pneumonia were significantly lower in districts with interventions. Case fatality rates due to acute diarrhoea and the proportion of severe pneumonia among ARI cases across the country showed a significant trend towards a decrease from 2004 to 2007. Nepal has succeeded in training many CHVs and is on course to meet the Millennium Development Goal for child mortality.

Lessons learnt

The burden of acute diarrhoea and ARIs can be reduced by training and engaging CHVs to implement community-based case management and prevention strategies. Monitoring, supervision and logistical support are essential. Policy decisions based on evidence from national research contributed to the success of the programme.     

Diet-microbiome-immune interplay in multiple sclerosis: Understanding the impact of phytoestrogen metabolizing gut bacteria

Multiple sclerosis (MS) is a chronic and progressive autoimmune disease of the central nervous system (CNS), with both genetic and environmental factors contributing to the pathobiology of the disease. Although HLA genes have emerged as the strongest genetic factor linked to MS, consensus on the environmental risk factors is lacking. Recently, the gut microbiota has garnered increasing attention as a potential environmental factor in MS, as mounting evidence suggests that individuals with MS exhibit microbial dysbiosis (changes in the gut microbiome). Thus, there has been a strong emphasis on understanding the role of the gut microbiome in the pathobiology of MS, specifically, factors regulating the gut microbiota and the mechanism(s) through which gut microbes may contribute to MS. Among all factors, diet has emerged to have the strongest influence on the composition and function of gut microbiota. As MS patients lack gut bacteria capable of metabolizing dietary phytoestrogen, we will specifically discuss the role of a phytoestrogen diet and phytoestrogen metabolizing gut bacteria in the pathobiology of MS. A better understanding of these mechanisms will help to harness the enormous potential of the gut microbiota as potential therapeutics to treat MS and other autoimmune diseases.     

The Association of Childhood Pneumonia with Household Air Pollution in Nepal: Evidence from Nepal Demographic Health Surveys

Introduction

Childhood pneumonia is a major cause of mortality worldwide while household air pollution (HAP) is a major contributor to childhood pneumonia in low and middle-income countries. This paper presents the prevalence trend of childhood pneumonia in Nepal and assesses its association with household air pollution.

Methods

The study analysed data from the 2006, 2011 and 2016 Nepal Demographic Health Surveys (NDHS). It calculated the prevalence of childhood pneumonia and the factors that cause household air pollution. The association of childhood pneumonia and HAP was assessed using univariate and multi-variate analysis. The population attributable fraction (PAF) of indoor pollution for causing pneumonia was calculated using 2016 NDHS data to assess the burden of pneumonia attributable to HAP factors.

Results

The prevalence of childhood pneumonia decreased in Nepal between 2006 and 2016 and was higher among households using polluting cooking fuels. There was a higher risk of childhood pneumonia among children who lived in households with no separate kitchens in 2011 [Adjusted risk ratio (ARR) 1.40, 95% CI 1.01–1.97] and in 2016 (ARR 1.93, 95% CI 1.14–3.28). In 2016, the risk of children contracting pneumonia in households using polluting fuels was double (ARR 1.98, 95% CI 1.01–3.92) that of children from households using clean fuels. Based on the 2016 data, the PAF for pneumonia was calculated as 30.9% for not having a separate kitchen room and 39.8% for using polluting cooking fuel.

Discussion for Practice

Although the occurrence of childhood pneumonia in Nepal has decreased, the level of its association with HAP remained high.