Croissance et caractérisation de nanostructures de Ge et Si déposées sur des substrats d'oxyde cristallin à forte permittivité LaA1O3

Les mémoires flash non volatiles - utilisées dans les ordinateurs, téléphones portables ou clés USB - peuvent être constituées de nanocristaux semiconducteurs (SC) insérées dans une matrice isolante. Elles nécessitent l'élaboration d'hétérostructures de type "oxyde/SC/oxyde/Si(00l)" et la maîtrise de chaque interface. Dans ce cadre, nous avons étudié les mécanismes de croissance initiale du Si et du Ge (SC) sur des substrats d'oxyde cristallins LaA1O3(001) à forte permittivité (high-k). Les propriétés chimiques et structurales ont été déterminées in-situ par photoémission X (XPS et XPD) et par diffraction d'électrons (RHEED et LEED) puis ex-situ par microscopies en champ proche (AFM) et en transmission (HRTEM). Le substrat LaAlO3(001) propre présente une reconstruction de surface c(2x2) attribuée à des lacunes d'O en surface. Les croissances de Si et Ge ont été réalisées par épitaxie par jet moléculaire (MBE), soit à température ambiante suivies de recuits, soit à haute température. L'épitaxie requiert des températures de dépôt supérieures à 550C. Le mode de croissance est de type Volmer Weber caractérisé par la formation d'îlots cristallins de dimensions nanométriques et de forte densité. Ces îlots sont relaxés et présentent une interface abrupte avec le substrat. Quant aux îlots de Ge, ils ont majoritairement des orientations aléatoires avec néanmoins une relation d'épitaxie privilégiée, la même que celle du Si.Non-volatile flash memory used in computers, mobile phones and USB-keys can be made up of nanocrystals (SC) inserted in an insulating matrix. It requires development of "Oxide/SC/oxide/Si (001)" type hetero-structures and the control of each interface. Within this framework, we studied the initial growth mechanisms of Si and Ge (SC) on LaA1O3(001) crystal oxide substrates with high permittivity (high-k). Chemical and structural properties have been studied in-situ by X-Ray photoemission (XPS and XPD) and electron diffraction (RHEED and LEED) technics and ex situ by atomic force microscopy (AFM) and high resolution tunneling electron microscopy (HRTEM). Clean LaA1O3(001) substrate contains a c(2x2) surface reconstruction which attributed to gaps of oxygen (O) on the surface. Si and Ge have been deposited by molecular bearn epitaxy (MBE), at room temperature followed by series of annealings at high temperatures. Epitaxy requires temperature more than 550C for the deposition. Volmer Weber growth mode was characterized by the formation of nanometric densely packed islands. These islands are relaxed and have an abrupt interface with the substrate. Islands of Ge have mostly random orientations with nevertheless epitaxy privileged relationship, same as that of the Si.MULHOUSE-SCD Sciences (682242102) / SudocSudocFranceF

Communicable Diseases Among Refugees with a Focus on the Middle East

During the past few years, millions of refugees from the Middle East and North Africa fled their countries to almost everywhere in the globe. Civil wars and acts of violence are the main reasons behind the exodus of populations seeking a better life and more secure living conditions. In fact, the current conflict in Syria and Iraq led to massive influx of refugees worldwide and in particular to neighboring countries of the Middle East. This refugee situation is unparalleled since the end of World War II. Besides the individual tragedies of refugees, a public health disaster is being witnessed in the countries of origin which, in many instances, affect the hosting countries as well. Many of these hosting countries witnessed a re-emergence of numerous communicable diseases as a result of the influx of refugees; they were unprepared, and their health sectors did not deliver the adequate response. In this chapter, we review major sexually transmitted diseases in refugees, with a focus on the Middle East. We also discuss the major actions taken in response to the ongoing displacement of refugees by the Government of Lebanon and suggest solutions and recommendations to the Lebanese public health system which is facing new urgent challenges

Oral manifestations of inflammatory bowel disease

Inflammatory bowel diseases (IBD), including Crohn\u2019s disease and ulcerative colitis, have important extraintestinal manifestations, notably in the oral cavity. These oral manifestations can constitute important clinical clues in the diagnosis and management of IBD, and include changes at the immune and bacterial levels. Aphthous ulcers, pyostomatitis vegetans, cobblestoning and gingivitis are important oral findings frequently observed in IBD patients. Their presentations vary considerably and might be well diagnosed and distinguished from other oral lesions. Infections, drug side effects, deficiencies in some nutrients and many other diseases involved with oral manifestations should also be taken into account. This article discusses the most recent findings on the oral manifestations of IBD with a focus on bacterial modulations and immune changes. It also includes an overview on options for management of the oral lesions of IBD

Multispacer sequence typing of Coxiella burnetii from milk and hard tick samples from ruminant farms in Lebanon

his study was carried out to detect and characterize Coxiella burnetii in ruminant milk samples and in different tick species from seropositive farms in four Lebanese regions. Milk and tick samples were screened for C. burnetii presence by quantitative real-time PCR (qPCR) targeting IS1111 region followed by multispacer sequence typing (MST). The overall positive percentages of 9.6% (27/282) and 95.45% (84/88) for C. burnetii were recorded in ruminant milk and tick samples, respectively. In detail, the C. burnetii DNA was recorded in 52/54 (96.3%) of Rhipicephalus annulatus, 20/21 (95.24%) of Rhipicephalus turanicus, 6/6 (100%) of Hyalomma anatolicum, 5/6 (83.3%) of Rhipicephalus sanguineus and 1/1 of Rhipicephalus bursa. After genotyping of some IS1111-positive samples (17/111), different MST genotypes were identified. Out of 15 positive ticks, 10 were infected with MST2 genotype, 4 were infected with MST7 genotype and 1 was infected with MST57. Moreover, genotypes MST20 and MST58 were found in one cow and one goat milk samples, respectively. The present study confirmed the high genetic diversity of C. burnetii in Lebanon

VALPROIC ACID INDUCES APOPTOSIS AND INCREASES CXCR7 EXPRESSION IN EPITHELIAL OVARIAN CANCER CELL LINE SKOV-3.

Background: The chemokine receptor, CXCR7 is described to play a biologically relevant role in tumor growth and spread. Recently, it was reported that CXCR7 overexpression is associated with an unfavorable prognosis and metastatis of epithelial ovarian cancer (EOC). Aware that, several reports indicated that Histone deacetylases (HDACs) regulate the expression and activity of many proteins involved in both cancer initiation and progression, the aim of this work, was to study the effect of the HDAC inhibitor valproic acid (VPA) on the expression of CXCR7 as well as its impact on survival function in the epithelial ovarian cell line (SKOV-3). Methods: cells were cultured with varying concentrations of VPA (1, 2, 3, 4, 5 and 10 mM) for different durations (0, 12 h, 24 h and 48 h). Cell survival was assessed by Neutral red assay and by colony counting which being stained with crystal violet. CXCR7 expression was determined at mRNA level using quantitative real-time PCR (qRT-PCR) or at the protein level using western blotting. Results: VPA reduces cell survival of SKOV-3 cancer cells. The inhibition effect of VPA was dose and time-dependent. Exposure to VPA at concentrations above 2 mM at 24 h resulted in an increase expression of CXCR7 at both the mRNA and protein levels . Conclusion: These observations provide, for the first time, a better insight into the epigenetic mechanisms involved in regulating CXCR7 expression in EOC and will open new avenues for evaluating drugs that specifically stimulate the apoptosis of EOC with minimal unwanted side effect

VALPROIC ACID INDUCES APOPTOSIS AND INCREASES CXCR7 EXPRESSION IN EPITHELIAL OVARIAN CANCER CELL LINE SKOV-3.

Background: The chemokine receptor, CXCR7 is described to play a biologically relevant role in tumor growth and spread. Recently, it was reported that CXCR7 overexpression is associated with an unfavorable prognosis and metastatis of epithelial ovarian cancer (EOC). Aware that, several reports indicated that Histone deacetylases (HDACs) regulate the expression and activity of many proteins involved in both cancer initiation and progression, the aim of this work, was to study the effect of the HDAC inhibitor valproic acid (VPA) on the expression of CXCR7 as well as its impact on survival function in the epithelial ovarian cell line (SKOV-3). Methods: cells were cultured with varying concentrations of VPA (1, 2, 3, 4, 5 and 10 mM) for different durations (0, 12 h, 24 h and 48 h). Cell survival was assessed by Neutral red assay and by colony counting which being stained with crystal violet. CXCR7 expression was determined at mRNA level using quantitative real-time PCR (qRT-PCR) or at the protein level using western blotting. Results: VPA reduces cell survival of SKOV-3 cancer cells. The inhibition effect of VPA was dose and time-dependent. Exposure to VPA at concentrations above 2 mM at 24 h resulted in an increase expression of CXCR7 at both the mRNA and protein levels . Conclusion: These observations provide, for the first time, a better insight into the epigenetic mechanisms involved in regulating CXCR7 expression in EOC and will open new avenues for evaluating drugs that specifically stimulate the apoptosis of EOC with minimal unwanted side effect

Sex disparities in food consumption patterns, dietary diversity and determinants of self-reported body weight changes before and amid the COVID-19 pandemic in 10 Arab countries

The COVID-19 pandemic along with its confinement period boosted lifestyle modifications and impacted women and men differently which exacerbated existing gender inequalities. The main objective of this paper is to assess the gender-based differentials in food consumption patterns, dietary diversity and the determinants favoring weight change before and amid the COVID-19 pandemic among Arab men and women from 10 Arab countries. A cross-sectional study was conducted based on a convenience sample of 12,447 households\u27 family members (mean age: 33.2 ± 12.9; 50.1% females) and information from participants aged 18 years and above was collected about periods before and during the pandemic. Findings showed that, during the COVID-19 period, the dietary diversity, declined by 1.9% among females compared to males (0.4%) (p \u3c 0.001) and by 1.5% among overweight participants (p \u3c 0.001) compared to their counterparts. To conclude, gender-sensitive strategies and policies to address weight gain and dietary diversity during emergent shocks and pandemics are urgently needed in the region

Dietary Diversity in the Eastern Mediterranean Region Before and During the COVID-19 Pandemic: Disparities, Challenges, and Mitigation Measures

The COVID-19 pandemic has revealed the Eastern Mediterranean Region's food system's fragility posing severe challenges to maintaining healthy sustainable lifestyle. The aim of this cross-sectional study (N = 13,527 household's family members, mean age: 30.3 ±11.6, 80% women) is to examine the impact of the COVID-19 pandemic on food consumption patterns and household's dietary diversity in 10 Eastern Mediterranean countries. A food frequency questionnaire was used to investigate the consumption patterns along with the calculation of the Food Consumption Score (FCS), a proxy indicator of dietary diversity. Data collected on cooking attitudes, shopping and food stock explore the community mitigation measures. In the overall population, before and during the pandemic, most food groups were consumed less or equal to 4 times per week. As evident from our findings and considering that the pandemic may be better, but it's not over, small to moderate changes in food consumption patterns in relatively short time periods can become permanent and lead to substantial poor dietary diversity over time. While it is a priority to mitigate the immediate impact, one area of great concern is the long-term effects of this pandemic on dietary patterns and dietary diversity in Eastern Mediterranean households. To conclude, the COVID-19 crisis revealed the region's unpreparedness to deal with a pandemic. While the aggressive containment strategy was essential for most countries to help prevent the spread, it came at a high nutritional cost, driving poor dietary diversity.This research was funded by the Research Foundation Flanders (G047518N) and Flanders Innovation and Entrepreneurship (HBC.2018.0397). These funding sources had no role in the design of the study, the analysis and interpretation of the data or the writing of, nor the decision to publish the manuscript

Call for emergency action to restore dietary diversity and protect global food systems in times of COVID-19 and beyond: Results from a cross-sectional study in 38 countries

Background: The COVID-19 pandemic has revealed the fragility of the global food system, sending shockwaves across countries' societies and economy. This has presented formidable challenges to sustaining a healthy and resilient lifestyle. The objective of this study is to examine the food consumption patterns and assess diet diversity indicators, primarily focusing on the food consumption score (FCS), among households in 38 countries both before and during the first wave of the COVID-19 pandemic. Methods: A cross-sectional study with 37 207 participants (mean age: 36.70 ± 14.79, with 77 % women) was conducted in 38 countries through an online survey administered between April and June 2020. The study utilized a pre-tested food frequency questionnaire to explore food consumption patterns both before and during the COVID-19 periods. Additionally, the study computed Food Consumption Score (FCS) as a proxy indicator for assessing the dietary diversity of households. Findings: This quantification of global, regional and national dietary diversity across 38 countries showed an increment in the consumption of all food groups but a drop in the intake of vegetables and in the dietary diversity. The household's food consumption scores indicating dietary diversity varied across regions. It decreased in the Middle East and North Africa (MENA) countries, including Lebanon (p < 0.001) and increased in the Gulf Cooperation Council countries including Bahrain (p = 0.003), Egypt (p < 0.001) and United Arab Emirates (p = 0.013). A decline in the household's dietary diversity was observed in Australia (p < 0.001), in South Africa including Uganda (p < 0.001), in Europe including Belgium (p < 0.001), Denmark (p = 0.002), Finland (p < 0.001) and Netherland (p = 0.027) and in South America including Ecuador (p < 0.001), Brazil (p < 0.001), Mexico (p < 0.0001) and Peru (p < 0.001). Middle and older ages [OR = 1.2; 95 % CI = [1.125–1.426] [OR = 2.5; 95 % CI = [1.951–3.064], being a woman [OR = 1.2; 95 % CI = [1.117–1.367], having a high education (p < 0.001), and showing amelioration in food-related behaviors [OR = 1.4; 95 % CI = [1.292–1.709] were all linked to having a higher dietary diversity. Conclusion: The minor to moderate changes in food consumption patterns observed across the 38 countries within relatively short time frames could become lasting, leading to a significant and prolonged reduction in dietary diversity, as demonstrated by our findings.Revisión por pare

Call for emergency action to restore dietary diversity and protect global food systems in times of COVID-19 and beyond: Results from a cross-sectional study in 38 countries

Background: The COVID-19 pandemic has revealed the fragility of the global food system, sending shockwaves across countries\u27 societies and economy. This has presented formidable challenges to sustaining a healthy and resilient lifestyle. The objective of this study is to examine the food consumption patterns and assess diet diversity indicators, primarily focusing on the food consumption score (FCS), among households in 38 countries both before and during the first wave of the COVID-19 pandemic. Methods: A cross-sectional study with 37 207 participants (mean age: 36.70 ± 14.79, with 77 % women) was conducted in 38 countries through an online survey administered between April and June 2020. The study utilized a pre-tested food frequency questionnaire to explore food consumption patterns both before and during the COVID-19 periods. Additionally, the study computed Food Consumption Score (FCS) as a proxy indicator for assessing the dietary diversity of households. Findings: This quantification of global, regional and national dietary diversity across 38 countries showed an increment in the consumption of all food groups but a drop in the intake of vegetables and in the dietary diversity. The household\u27s food consumption scores indicating dietary diversity varied across regions. It decreased in the Middle East and North Africa (MENA) countries, including Lebanon (p \u3c 0.001) and increased in the Gulf Cooperation Council countries including Bahrain (p = 0.003), Egypt (p \u3c 0.001) and United Arab Emirates (p = 0.013). A decline in the household\u27s dietary diversity was observed in Australia (p \u3c 0.001), in South Africa including Uganda (p \u3c 0.001), in Europe including Belgium (p \u3c 0.001), Denmark (p = 0.002), Finland (p \u3c 0.001) and Netherland (p = 0.027) and in South America including Ecuador (p \u3c 0.001), Brazil (p \u3c 0.001), Mexico (p \u3c 0.0001) and Peru (p \u3c 0.001). Middle and older ages [OR = 1.2; 95 % CI = [1.125–1.426] [OR = 2.5; 95 % CI = [1.951–3.064], being a woman [OR = 1.2; 95 % CI = [1.117–1.367], having a high education (p \u3c 0.001), and showing amelioration in food-related behaviors [OR = 1.4; 95 % CI = [1.292–1.709] were all linked to having a higher dietary diversity. Conclusion: The minor to moderate changes in food consumption patterns observed across the 38 countries within relatively short time frames could become lasting, leading to a significant and prolonged reduction in dietary diversity, as demonstrated by our findings