Вплив товщини плівки на властивості тонких плівок Co-ZnO, отриманих золь-гель методом

Тонкі плівки ZnO, леговані 1 мас. % Co (CZO) різної товщини (3, 5 і 7 шарів, що відповідають товщині 403, 545 і 725 нм) наносяться золь-гель методом на скляні підкладки технікою нанесення покриттів зануренням. Дегідрат ацетату цинку, ацетат кобальту, 2-метоксиетанол і етаноламін використовуються відповідно як первинні матеріали, розчинник і стабілізатор. Термічно відпалені плівки охарактеризовано для вивчення структури, морфології поверхні, електричних та оптичних властивостей. Дифракція рентгенівських променів (XRD) показує, що ці плівки мають полікристалічну гексагональну структуру (структура вюрциту з просторовою групою P63mc), володіють напругою стиску та мають переважну орієнтацію вздовж площини (002). Відзначимо, що при збільшенні товщини розмір частинок зменшується. Морфологію поверхні отриманих тонких плівок CZO досліджують за допомогою атомно-силової мікроскопії (АFМ). Вона виявляє появу однорідної стовпчастої структури та показує, що розмір частинок і середньоквадратична шорсткість CZO збільшуються зі збільшенням товщини. УФ-видима спектроскопія показує (у видимій області) пропускання від 75 до 86 % для всіх плівок, сильне поглинання (в УФ-області) і зменшення оптичної забороненої зони. Крім того, товщина впливає на ближній край смуги (NBE) і видиме випромінювання, що виявляється фотолюмінесценцією. Електропровідність зразка з довжиною хвилі 725 нм становить 4,43 (Ом∙см) – 1.1 wt. % Co-doped ZnO (CZO) thin films of varying thicknesses (3, 5 and 7 layers, which correspond to 403, 545 and 725 nm as thickness) are deposited using the sol-gel method onto glass substrates by dip coating technique. Zinc acetate dehydrate, cobalt acetate, 2-methoxyethanol and ethanolamine are used as primary materials, solvent and stabilizer, respectively. The thermally annealed films are characterized to study the structural, surface morphology, electrical and optical properties. X-ray diffraction (XRD) shows that these films have a polycrystalline hexagonal structure (wurtzite structure with space group P63mc), possessing compressive stress and presenting a preferred orientation along the (002) plane. We note that the particle size increases when the thickness increases. The surface morphology of the prepared CZO thin films is investigated by atomic force microscopy (AFM). It reveals the emergence of a uniform columnar structure and shows that the particle size and the root mean square (RMS) of CZO increase with increasing thickness. UV-visible spectroscopy shows (in the visible region) a transmittance between 75 and 86 % for all the films, strong absorption (in the UV region) and a decrease in the optical band gap. Moreover, the near band edge (NBE) and visible emissions detected by photoluminescence are affected by the thickness. The electrical conductivity of the sample with 725 nm is found to be 4.43 (Ω∙cm) – 1

Applications des bactériocines et bactéries lactiques dans le contrôle des pathogènes alimentaires

International audienc

La Galite Archipelago (Tunisia, North Africa): new geological data and insights for geodynamic evolution of the Maghrebian Chain (African-European plate boundary)

The location of the La Galite Archipelago on the Internal/External Zones of the Maghrebian Chain holds strong interest for the reconstruction of the geodynamic evolution of the Mesomediterranean Microplate-Africa Plate Boundary Zone.New stratigraphic and petrographic data on sedimentary successions intruded upon by plutonic rocks enabled a better definition of the palaeogeographic and palaeotectonic evolutionary model of the area during the early-middle Miocene.The lower Miocene sedimentary units (La Galite Flysch and Numidian-like Flysch) belong to the Mauritanian (internal) and Massylian (external) sub-Domains of the Maghrebian Chain, respectively. These deposits are related to a typical syn-orogenic deposition in the Maghrebian Flysch Basin Domain, successively backthrusted above the internal units. The backthrusting age is post-Burdigalian (probably Langhian-Serravallian) and the compressional phase represents the last stage in the building of the accretionary wedge of the Maghrebian orogen. These flysch units may be co-relatable to the similar well-known formations along the Maghrebian and Betic Chains.The emplacement of potassic peraluminous magmatism, caused local metamorphism in the Late Serravallian-Early Tortonian (14–10 Ma), after the last compressional phase (backthrusting), during an extensional tectonic event. This extensional phase is probably due to the opening of a slab break-off in the deep subduction system.La Galite Archipelago represents a portion of the Maghrebian Flysch Basin tectonically emplaced above the southern margin of the “Mesomediterranean Microplate” which separated the Piemontese-Ligurian Ocean from a southern oceanic branch of the Tethys (i.e. the Maghrebian Flysch Basin).The possible presence of an imbricate thrust system between La Galite Archipelago and northern Tunisia may be useful to exclude the petroleum exploration from the deformed sectors of the offshore area considered

Zoonotic Tuberculosis: A Neglected Disease in the Middle East and North Africa (MENA) Region

Mycobacterium bovis is the etiologic agent of bovine tuberculosis (BTB), a serious infectious disease in both humans and animals. BTB is a zoonotic disease primarily affecting cattle and occasionally humans infected through close contact with infected hosts or the consumption of unpasteurized dairy products. Zoonotic tuberculosis is strongly associated with poverty and poor hygiene, and low- and middle-income countries bear the brunt of the disease. BTB has been increasingly recognized as a growing public health threat in developing countries. However, the lack of effective surveillance programs in many of these countries poses a barrier to accurately determining the true burden of this disease. Additionally, the control of BTB is threatened by the emergence of drug-resistant strains that affect the effectiveness of current treatment regimens. Here, we analyzed current trends in the epidemiology of the disease as well as the antimicrobial susceptibility patterns of M. bovis in the Middle East and North Africa (MENA) region, a region that includes several developing countries. Following PRISMA guidelines, a total of 90 studies conducted in the MENA region were selected. Our findings revealed that the prevalence of BTB among humans and cattle varied significantly according to the population size and country in the MENA region. Most of the available studies were based on culture and/or PCR strategies and were published without including data on antimicrobial resistance and molecular typing. Our findings highlighted the paramount need for the use of appropriate diagnostic tools and the implementation of sustainable control measures, especially at the human/animal interface, in the MENA region