A Half-analytical Elastic Solution for 2D Analysis of Cracked Pavements

International audienceThis paper presents a half-analytical elastic solution convenient for parametric studies of 2D cracked pavements. The pavement structure is reduced to three elastic and homogeneous equivalent layers resting on a soil. In a similar way than the Pasternak's modelling for concrete pavements, the soil is modelled by one layer, named shear layer, connected to Winkler's springs in order to ensure the transfer of shear stresses between the pavement structure and the springs. The whole four-layer system is modelled using a specific model developed for the analysis of delamination in composite materials. It reduces the problem by one dimension and gives access to regular interface stresses between layers at the edge of vertical cracks allowing the initial debonding analysis. In 2D plane strain conditions, a system of twelve-second order differential equations is written analytically. This system is solved numerically by the finite difference method (Newmark) computed in the free Scilab software. The calculus tool allows analysis of the impact of material characteristics changing, loads and locations of cracks in pavements on the distribution of mechanical fields. The approach with fracture mechanic concepts is well suited for practical use and for some subsequent numerical developments in 3D

Immune Response of Molluscs

In common with other invertebrates, molluscs are known to have internal immune response against foreign particles and organisms. The innate immunity of molluscs reflects the inherent non-specific response that provides the first line of defense. Anatomic barriers, phagocytic cells, and physiological components are the main elements of the innate immune response in molluscs. It is composed of both cellular and humoral elements. The cellular components are the circulating hemocytes. Small invaders are eliminated by the phagocytic hemocytes, while large invaders are eliminated by encapsulation. The ingested foreign particles are then hemolyzed by the action of certain toxic enzymes that catalyze oxidative burst reactions capable of killing pathogens and foreign invaders. Humoral components of molluscan immunity involve nitric oxide, lysozyme activity, lectins, and the phenyloxidase system. The current chapter sheds light on the elements of the molluscan innate immune system and presents a case study of the immune response of Lymnaea stagnalis mollusc against Chaetogaster limnaei parasite. The effect of the parasite on some humoral immune response parameters such as nitric oxide, phenol oxidase, and lysozyme production was investigated. In conclusion, the snail Lymnaea stagnalis exerts humoral immune response against Chaetogaster limnaei parasite. However, this response is insufficient to eliminate the parasite

Role of Poultry Research in Increasing Consumption of PUFA in Humans

In recent years, polyunsaturated fatty acids (PUFA) have received considerable attention in both human and animal nutrition. As a mean of increasing the low consumption of long chain n-3 PUFA by humans consuming diets, there has been some interest in the enrichment of poultry meat with these fatty acids for people seeking healthy lifestyles. Dietary supplementation with n-3 PUFA, such as these found in fish oil and linseed oil, were found to have nutritional benefits in humans. Modulation of fatty acid profiles as a result of n-3 PUFA incorporation is well documented in humans, rodents, and poultry. The current chapter focuses on enriching poultry meat with these beneficial fatty acids to increase its consumption by human beings

Expression of e-cadherin, n-cadherin and snail and their correlation with clinicopathological variants: an immunohistochemical study of 132 invasive ductal breast carcinomas in Egypt

OBJECTIVE: To evaluate the expression of the cell adhesion molecules E-cadherin and N-cadherin and the transcription factor Snail in invasive ductal breast carcinomas and to determine their relationships with clinicopathological features. METHODS: Immunohistochemistry was used to examine E-cadherin, N-cadherin, and Snail protein expression in 132 invasive breast carcinomas. RESULTS: The expression of E-cadherin was decreased (negative or weak) in 37.1% of invasive carcinomas, while N-cadherin and Snail overexpression were detected in 51.9% and 40.9% of carcinomas, respectively. Low E-cadherin expression was significantly correlated with poorly differentiated carcinoma (53.1%), positive node status (80.9%), poor Nottingham Prognostic Index (64.7%), and the presence of estrogen and progesterone receptors. Overexpression of N-cadherin and Snail were also significantly correlated with poorly differentiated carcinoma, positive node status, and poor Nottingham Prognostic Index but were correlated with the absence of hormone receptors. Loss of E-cadherin immunoexpression was strongly associated with the presence of membranous N-cadherin (87.8%) and nuclear Snail (69.4%). CONCLUSION: Loss of E-cadherin and overexpression of N-cadherin and Snail in breast carcinomas may play a central role in the development of invasive ductal breast carcinoma. These biomarkers may provide a valuable reference for the study of invasive ductal carcinoma progression and to characterize the biological behavior of the tumor. In the future, increased N-cadherin and decreased E-cadherin expression may be used as indicators of the progression and prognosis of invasive ductal carcinoma

Outil 2D d'analyse mécanique et paramétrique des chaussées fissurées

Ce papier présente un outil de calcul rapide et utile à l'ingénieur pour l'analyse des champs mécaniques dans les structures multicouches de chaussée fissurées. La chaussée est choisie équivalente à trois couches élastiques et homogènes reposant sur un sol. Le sol est modélisé au moyen d'une couche dite de cisaillement ajoutée à un massif de ressorts élastiques (Massif de Winkler) afin d'assurer le transfert des contraintes de cisaillement entre la chaussée et les ressorts. Le quadri-couche total (3 couches de chaussée plus 1 couche de cisaillement) est modélisé à l'aide d'un modèle simplifié (M4-5n) développé pour l'analyse du délaminage des matériaux composites. Le système de douze équations différentielles d'ordre 2 résultant, écrit complètement analytiquement, est résolu par différences finies (Newmark) dans le cas 2D des déformations planes. Sur une chaussée contenant une fissure verticale le long d'une de ses couches, les solutions semi-analytiques sont obtenues en moins d'une seconde. Cet outil autorise ainsi des études paramétriques telles que la distribution des champs mécaniques (en particulier les contraintes d'interface) en fonction de la position de la charge plus ou moins distante de la fissure verticale. Cette nouvelle modélisation montre son efficacité par rapport à l'emploi d'un code aux éléments finis classique

Mixed FE solution of the layerwise model M4-5n with emphasis on embedded discontinuities

CFRAC2017, Fifth International Conference on Computational Modeling of Fracture and Failure of Materials and Structures, NANTES, FRANCE, 14-/06/2017 - 16/06/2017A general solving method for the plate-type model called M4-5n, relying on mixed finite elements is presented hereafter. In particular, we explain how embedded discontinuities in a multilayer pavement structure can be easily taken into account using the numerical approach developed... As an illustration, the approach developed is used to simulate the mechanical response of a pavement structure with cracks on which a full-scale accelerated fatigue test was performed

The Role of UNICEF's Intervention Programs in Improving Polio Coverage During the Humanitarian Crisis in Yemen

Even before the current crisis, the humanitarian situation in Yemen was suffering from many problems affecting the life’s standards of the population. The poor humanitarian situation in the country resulted from many factors such as political instability, multiple localized conflicts and chronic underdevelopment. All those factors led Yemen to become one of the poorest countries in the Middle East as the majority of its population lives below the poverty threshold. Moreover, when the armed conflict started in March 2015 the civilian infrastructures in the country impacted heavily including hospitals, schools, roads, bridges, public services such as water and sanitation services. In addition, the whole country started experiencing a great shortage of supplies such as food and medications which unfortunately caused mass risks to millions of people. Polio is one of the highest infectious viral diseases affecting young children, although it is considered a vaccine-preventable disease the children in Yemen still exposing to it. Therefore, fighting against polio was one of the United Nations Children's Fund (UNICEF) battles as children in Yemen were always exposed to the danger of being affected by that disease. This research aims to provide an assessment regarding the major interventions that UNICEF uses to deliver the immunization service including polio vaccines to children during the current humanitarian crisis in the country. The data collection was conducted by using a mixed-method to collect the data from 108 sampled households in addition to the structured interviews with the key informant personnel such as the health facilities management, immunization supervisors and UNICEF’s key personnel. The analysis of the results showed that UNICEF’s support has a positive impact on the immunization programme in Yemen. However, a point to be highlighted is that the coverage rate improves slowly due to several challenges faced by the population during the humanitarian crisis. The massive displaced movement due to the conflict caused more iv pressure on the health facilities which became unable to provide some areas with immunization services. The conflict also causes a decrease in the number of mobile immunization teams and national vaccination campaigns. In addition, it was found that many immunization interventions are carried out without developing a monitoring plan or training the health workers on the reporting system including data collection, analysis and calculating coverage rate or drop-out rate. This study proposed recommendations to resolve these challenges, the aid agencies such as UNICEF need to put some pressure on the conflict parties to facilitate the INGOs' work without delaying their humanitarian aids. Also, UNICEF needs to prioritize its financial and technical support to increase the number of health personnel in the expanded programme on immunization staff and mobile immunization members to be able to deliver the immunization services and handle the extra workload caused by the current humanitarian crisis. The study also recommends strengthening the immunization information system at all levels; monitoring, evaluation, on-site supervision and disease surveillance. The immunization programme should develop a detailed monitoring and evaluation plan to ensure acceptable standards of quality and effectiveness in the implemented immunization interventions

Childhood and adolescent obesity: Primary Health Care Physicians’ perspectives from Riyadh, Saudi Arabia

BACKGROUND & OBJECTIVES: Primary health care (PHC) physicians are foremost to confront childhood and adolescent obesity. Our objective was to evaluate PHC Physicians perspectives for managing overweight/obesity in children and adolescents. METHODS: PHC services from eight public hospitals in Riyadh participated. A self-administered tool maintaining anonymity evaluated facilitators and barriers for managing overweight/obese children and adolescent patients. Physicians who \u27always\u27 recommended weight management for an overweight / obese patient during past year, by involving patient, parents, and others were classified as having positive and appropriate practice. RESULTS: Of the 58 respondents, 51.7% had appropriate practices. Lack of patient motivation (82.2%), and parental involvement (70.7%) were the major barriers. Physicians with appropriate practices differed in perspectives from those with less appropriate practices by attending continued education forums (p\u3c0.026), referring patients to sub-specialty (p\u3c 0.041), clinical knowledge (p\u3c0.039), convinced on interventions (p\u3c0.017), low concern for precipitating eating disorders (p\u3c0.019), comfortable in examining obese patients (p\u3c0.020), and considered patient\u27s readiness for weight change (p\u3c 0.007). CONCLUSION: Efforts are needed to equip PHC physicians in managing overweight and obesity in Saudi children and adolescents

Selected Dietary Nutrients and the Prevalence of Metabolic Syndrome in Adult Males and Females in Saudi Arabia: A Pilot Study

published_or_final_versio