Novel wet laid nonwoven carbon fiber mats and their composites

In the wake of lightweight and specific strength, composite materials are increasingly used for few decades. In order to meet the industry production rates, a novel mixing method has been developed in this work that provides more control on fiber length and homogeneity in wet-laid (WL) carbon fiber (CF) mats. The WL process has been adopted from papermaking industries to produce non-woven CF fiber mats.This work investigates the production of CF mats in three main phases; (a) First, the mixing regime of the WL method is explored to optimize the process of fiber dispersion. Experimental and theoretical computational fluid dynamics (CFD) studies have been conducted to understand the different factors of the process, in order to obtain the most optimal time of production. Mats produced are imaged through the Back Light Scattering (BLS) technique and computationally analyzed using a Matlab generated code to determine the fiber density distribution through pixel counts and compare the improved results of the mixing method developed in this work to the traditional propeller mixing. Processing time was reduced by 60% to produce a mat on laboratory scale with optimal characteristics; (b) Second composites were made from mats produced by each of the two mixing methods presented in the first part of the work. An object oriented finite element analysis (OFF) investigated the isotropic nature of the composites. The mechanical properties of these composites were evaluated in tensile, flex and inter laminar shear (ILSS). Tensile data showed improvement in standard deviation between samples collected from plates made with mats produced through the innovated mixing method when comparing them to composites made with the mats produced through the traditional method; and (c) Third, the in-plane permeability of the mats was analyzed in respect to changes in the fiber length and mats grammage per square meter (gsm) and a link between local permeability in response to changes in complex geometries is investigated.The novel mixing method for fiber distribution in WL discussed in this work presents an innovation in composites production, leading to improved production rate of nonwoven CF mats, ease of production and reproducibility of composites

Biopsy-Proven Acute Tubular Necrosis due to Vancomycin Toxicity

Vancomycin (VAN) has been associated with acute kidney injury (AKI) since it has been put into clinical use in the 1950's. Early reports of AKI were likely linked to the impurities of the VAN preparation. With the advent of the more purified forms of VAN, the incidence of AKI related to VAN were limited to acute interstitial nephritis (AIN) or as a potentiating agent to other nephrotoxins such as Aminoglycosides. VAN as the sole etiologic factor for nephrotoxic acute tubular necrosis (ATN) has not been described. Here, we report a case of biopsy-proven ATN resulting from VAN

Numerical Validation of Analytical Homogenization Models for the Case of Randomly Distributed and Oriented Ellipsoidal Fibers Reinforced Composites

Résumé Le développement de nouveaux matériaux composites peut s'avérer long et coûteux. Il serait alors pertinent d'avoir des outils capables de prédire le comportement mécanique de matériaux composites avant qu'ils ne soient réellement fabriqués. L'utilisation de tels outils permettrait de réduire le temps et les coûts reliés aux tests de certification. Plusieurs méthodes analytiques existent pour prédire les propriétés mécaniques de composites. Les plus connues sont la règle des mélanges et la théorie classique des laminés. Dans la plupart des cas, ces méthodes fournissent des prédictions inexactes puisqu'elles ne prennent pas en considération toute l'information disponible reliée à la microstructure. Les modèles d'homogénéisation analytiques prédisent les propriétés mécaniques effectives de matériaux hétérogènes en utilisant des informations reliées à la microstructure (les propriétés des phases, leur fraction volumique, la forme et l'orientation des renforts, etc.). Toutefois, il n'existe pas d'étude systématique et approfondie où l'on évalue la précision de ces modèles pour une vaste gamme de propriétés mécaniques et géométriques des phases. Dans le but de valider la performance des modèles analytiques, leurs prédictions doivent être comparées à celles obtenues par des méthodes numériques. Les différentes méthodes numériques utilisées dans la littérature sont coûteuses en terme de temps de calcul, ce qui a limité la gamme de composites étudiée. De plus, la plupart des études ont été réalisées sans avoir rigoureusement déterminé le Volume Élémentaire Représentatif (VER). L'objectif principal de cette thèse était de valider la performance des modèles d'homogénéisation analytiques à prédire les propriétés mécaniques effectives et les statistiques des champs locaux de composites renforcés par des fibres elliptiques aléatoirement distribuées et orientées. Étant donnée qu'une grande campagne de validation était planifiée, un outil numérique complètement automatisé a été développé. Ce dernier a traité deux étapes indépendantes: i)la génération aléatoire des microstructures représentatives et ii)le calcul exact des propriétés effectives. Les microstructures représentatives ont été générées en utilisant une approche basée sur la dynamique moléculaire. Un nouveau algorithme performant et efficace a été développé dans le but de générer des arrangements constitués d'ellipsoïdes aléatoirement distribués et orientés. L'algorithme proposé a été capable de générer tous les types d'ellipsoïdes à hautes fractions volumiques et/ou rapports de forme. Les propriétés effectives et les statistiques des champs locaux ont été obtenues avec précision en utilisant une technique basée sur les Transformées de Fourier Rapides (TFR). Les prédictions de l'outil numérique ont été comparées à celles des modèles d'homogénéisation analytiques les plus connus pour une vaste gamme de propriétés mécaniques des phases et de fractions volumiques et rapports de forme des fibres. La campagne de validation a impliqué un rigoureux processus de détermination du VER et approximativement 1800 différents composites à fibres elliptiques ont été étudiés.----------ABSTRACT The development of new composite materials can be a long and expensive process. It would therefore be relevant to have predictive tools that can predict the mechanical behavior of composites before their fabrication. Using these tools could lead to shorter certification time and cost reductions. Several analytical approaches exist for predicting the mechanical properties of composites. The best known are the Rule of Mixtures and the Classical Lamination Theory. In most cases, both approaches lead to inaccurate predictions since they do not take into account all the available information about the microstructure. Analytical homogenization models rely on microstructural information (e.g., constituents properties, volume fraction, shape, orientation, etc.) to predict the effective mechanical properties of heterogeneous materials. However, no systematic and thorough study evaluates the accuracy of these models for a wide range of constituents mechanical and geometrical properties. In order to validate the performance of analytical models, their predictions should be compared to those obtained by numerical methods. The different numerical methods that have been used in the literature had a high computational cost, which has limited the investigated range of composites. Furthermore, most numerical studies were performed without conducting a rigorous Representative Volume Element (RVE) determination process. The main purpose of this thesis was to validate the performance of analytical homogenization models at predicting the effective mechanical properties and local field statistics of randomly distributed and oriented ellipsoidal fibers reinforced composites. Since a large validation campaign was planned, a fully automated numerical tool was developed. The latter dealt with two independent steps: i)random generation of the representative microstructures and ii) accurate computation of the effective properties. The representative microstructures were generated using a molecular dynamics approach. A new computationally-efficient algorithm was developed for generating packings of randomly distributed and oriented ellipsoids. The proposed algorithm was able to generate all types of ellipsoids with high volume fractions and/or aspect ratios. The effective properties and local field statistics were accurately computed using a Fast Fourier Transforms (FFT) based technique. The predictions of the numerical tool were compared to those of the best known analytical homogenization models for a broad range of phases mechanical properties, fibers volume fractions and aspect ratios. The validation campaign involved a thorough and rigorous RVE determination process and approximately, 1800 different ellipsoidal fibers reinforced composites were studied. A validity domain was attributed to each analytical model. It was found that no analytical homogenization model stands out of the others as being more accurate over the studied range of phases mechanical and geometrical properties. However, if a single model was to be chosen to predict the effective properties and local field statistics of ellipsoidal fibers reinforced composites, this thesis recommend the Lielens' model

Identification of Enhancer of Zeste Homolog 2 Expression in Peripheral Circulating Tumor Cells in Metastatic Prostate Cancer Patients: A Preliminary Study

transcriptional repressor, is reportedly over-expressed in metastatic prostate cancer. In this study, we analyzed EZH2 mRNA in circulating tumor cells (CTCs) in peripheral blood as a biomarker in patients with metastatic prostate cancer. Patients and Methods: Ber-EP4 coated immunomagnetic beads were used to harvest CTCs, and mRNA was isolated by oligodT conjugated immunomagnetic beads. Reverse transcriptasepolymerase chain reaction for EZH2 mRNA was performed and the expression density was measured. The sensitivity of this test for detection of EZH2 mRNA was determined by serial dilutions of a human prostate cancer cell line. Blood samples were collected from 20 patients each with metastatic or localized prostate cancer and 10 healthy volunteers. Results: Sensitivity experiments showed that the test was highly sensitive as it could detect 10 tumor cells per 5 mL. EZH2 mRNA expression was obtained from peripheral blood samples of patients and control subjects. EZH2 mRNA expression density in the metastatic prostate cancer group was significantly higher than in the control (p = 0.023) and localized prostate cancer groups (p = 0.019). There was no difference between the control and localized prostate cancer groups (p> 0.05). Conclusion: EZH2 mRNA expression in circulating epithelial cells represents a promising marker for detecting early metastasis in prostate cancer. However, more specific and sensitive techniques for detection of CTCs are needed to avoid mononuclear cell contamination

Public procurement, regional integration, and the belt and road initiative

Published: 21 May 2021China's Belt and Road Initiative (BRI) is a mechanism through which countries can upgrade connectivity-related infrastructure, including through cross-border projects, complementing traditional sources of finance. An overarching goal of the BRI is to reduce trade costs between China and partner countries, in part by helping to integrate regional markets. The large-scale borrowing associated with BRI projects has given rise to potential debt servicing and sustainability concerns. The rate of return of BRI regional infrastructure projects depends in part on the integrity of public procurement processes and realizing value-for-money objectives. To date BRI projects financed by Chinese institutions have been largely awarded to Chinese companies. Enhancing transparency of BRI procurement processes and international cooperation among countries participating in the BRI would help achieve value for money goals and support the integration of BRI countries

Review: Carbon Nanotubes and Chronic Granulomatous Disease

Use of nanomaterials in manufactured consumer products is a rapidly expanding industry and potential toxicities are just beginning to be explored. Combustion-generated multiwall carbon nanotubes (MWCNT) or nanoparticles are ubiquitous in non-manufacturing environments and detectable in vapors from diesel fuel, methane, propane, and natural gas. In experimental animal models, carbon nanotubes have been shown to induce granulomas or other inflammatory changes. Evidence suggesting potential involvement of carbon nanomaterials in human granulomatous disease, has been gathered from analyses of dusts generated in the World Trade Center disaster combined with epidemiological data showing a subsequent increase in granulomatous disease of first responders. In this review we will discuss evidence for similarities in the pathophysiology of carbon nanotube-induced pulmonary disease in experimental animals with that of the human granulomatous disease, sarcoidosis

Effect of pregnancy prolongation in early-onset pre-eclampsia on postpartum maternal cardiovascular, renal and metabolic function in primiparous women: an observational study.

OBJECTIVE: To evaluate the association between deferred delivery in early-onset pre-eclampsia and offspring outcome and maternal cardiovascular, renal and metabolic function in the postpartum period. DESIGN: Observational study. SETTING: Tertiary referral hospital. POPULATION: Nulliparous women diagnosed with pre-eclampsia before 34 weeks' gestation who participated in a routine postpartum cardiovascular risk assessment programme. Women with hypertension, diabetes mellitus or renal disease prior to pregnancy were excluded. METHODS: Regression analyses were performed to assess the association between pregnancy prolongation and outcome measures. MAIN OUTCOME MEASURES: Offspring outcome and prevalence of deviant maternal cardiovascular, renal and metabolic function. RESULTS: The study population included 564 women with a median pregnancy prolongation of 10 days (interquartile range [IQR] 4-18) who were assessed at on average 8 months (IQR 6-12) postpartum. Pregnancy prolongation after diagnosis resulted in a decrease in infant mortality (adjusted odd ratio [aOR] 0.907, 95% CI 0.852-0.965 per day prolongation). This improvement in offspring outcome was associated with an elevated risk of moderately increased albuminuria (aOR 1.025, 95% CI 1.006-1.045 per day prolongation), but not with aberrant cardiac geometry, cardiac systolic or diastolic dysfunction, persistent hypertension or metabolic syndrome. CONCLUSION: Pregnancy prolongation in early-onset pre-eclampsia is associated with improved offspring outcome and survival. These effects do not appear to be deleterious to short-term maternal cardiovascular and metabolic function but are associated with a modest increase in risk of residual albuminuria. TWEETABLE ABSTRACT: Pregnancy prolongation in pre-eclampsia has only a limited effect on postpartum maternal cardiovascular function

Update to the College of American Pathologists Reporting on Thyroid Carcinomas

Background The reporting of thyroid carcinomas follows the recommendations of the College of American Pathologists (CAP) protocols and includes papillary carcinoma, follicular carcinoma, anaplastic carcinoma and medullary carcinoma. Despite past and recent efforts, there are a number of controversial issues in the classification and diagnosis of thyroid carcinomas (TC) that, potentially impact on therapy and prognosis of patients with TC. Discussion The most updated version of the CAP thyroid cancer protocol incorporates recent changes in histologic classification as well as changes in the staging of thyroid cancers as per the updated American Joint Commission on Cancer staging manual. Among the more contentious issues in the pathology of thyroid carcinoma include the defining criteria for tumor invasiveness. While there are defined criteria for invasion, there is not universal agreement in what constitutes capsular invasion, angioinvasion and extrathyroidal invasion. Irrespective of the discrepant views on invasion, pathologists should report on the presence and extent (focal, widely) of capsular invasion, angioinvasion and extrathyroidal extension. These findings assist clinicians in their assessment of the recurrence risk and potential for metastatic disease. It is beyond the scope of this paper to detail the entire CAP protocol for thyroid carcinomas; rather, this paper addresses some of the more problematic issues confronting pathologists in their assessment and reporting of thyroid carcinomas. Conclusion The new CAP protocol for reporting of thyroid carcinomas is a step toward improving the clinical value of the histopathologic reporting of TC. Large meticulous clinico-pathologic and molecular studies with long term follow up are still needed in order to increase the impact of microscopic examination on the prognosis and management of TC

Cardiac output assessment in pregnancy: comparison of two automated monitors with echocardiography.

OBJECTIVE: To compare non-invasive hemodynamic measurements obtained in pregnant and postpartum women using two automated cardiac output monitors against those obtained by two-dimensional (2D) transthoracic echocardiography (TTE). METHODS: This was a cross-comparison study into which we recruited 114 healthy women, either with normal singleton pregnancy (across all three trimesters) or within 72 hours following delivery. Cardiac output estimations were obtained non-invasively using two different monitors, Ultrasound Cardiac Output Monitor (USCOM®, which uses continuous-wave Doppler analysis of transaortic blood flow) and Non-Invasive Cardiac Output Monitor (NICOM®, which uses thoracic bioreactance), and 2D-TTE. The performance of each monitor was assessed relative to that of TTE by calculating bias, precision, 95% limits of agreement and mean percentage difference (MPD). Intraobserver repeatability was assessed for both monitors and interobserver reproducibility was assessed for USCOM, NICOM being operator-independent. RESULTS: Following exclusions due to poor-quality results of a monitor or TTE, or for medical reasons, our analysis included 98 women (29 in the first trimester, 25 in the second and 21 in the third, and 23 postpartum). For cardiac output estimation, when compared with TTE, USCOM had a bias ranging from 0.4 to 0.9 L/min. The MPD of USCOM was 29% in the third-trimester cohort. NICOM had a bias ranging from -1.0 to 0.6 L/min, with a MPD of 32% in the third-trimester group. There was limited agreement between the cardiac output monitors and TTE in the first and second trimesters, with a MPD of 38% for USCOM in both first and second trimesters, and 71% and 61% for NICOM in first and second trimesters, respectively. For cardiac output estimation using USCOM, we found excellent intraobserver repeatability (intraclass correlation coefficient (ICC), 0.97; 95% CI, 0.95-0.98) and interobserver reproducibility (ICC, 0.90; 95% CI, 0.81-0.94), and the repeatability for NICOM was comparable (ICC, 0.95; 95% CI, 0.93-0.97). CONCLUSIONS: We found good agreement of both USCOM and NICOM when compared with 2D-TTE, specifically in the third trimester of pregnancy. Both devices had good intraobserver repeatability and either had good interobserver reproducibility or were operator-independent. Future studies should take into account the significant differences in the precise maternal hemodynamic values obtained by these devices, and consider developing device-specific reference ranges in pregnancy and the postpartum period. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd