60 research outputs found
Molecular epidemiology of canine parvovirus in Morocco
No full textSince it first emergence in the mid-1970's, canine parvovirus 2 (CPV-2) has evolved giving rise to new antigenic variants termed CPV-2a, CPV-2b and CPV-2c, which have completely replaced the original strain and had been variously distributed worldwide. In Africa limited data are available on epidemiological prevalence of these new types. Hence, the aim of the present study was to determine circulating variants in Morocco. Through TaqMan-based real-time PCR assay, 91 samples, collected from symptomatic dogs originating from various cities between 2011 and 2015, were diagnosed. Positive specimens were characterised by means of minor groove binder (MGB) probe PCR. The results showed that all samples but one (98.9%) were CPV positive, of which 1 (1.1%) was characterised as CPV-2a, 43 (47.7%) as CPV-2b and 39 (43.3%) as CPV-2c. Interestingly, a co-infection with CPV-2b and CPV-2c was detected in 4 (4.4%) samples and 3 (3.3%) samples were not characterised. Sequencing of the full VP2 gene revealed these 3 uncharacterised strains as CPV-2c, displaying a change G4068A responsible for the replacement of aspartic acid with asparagine at residue 427, impacting the MGB probe binding. In this work we provide a better understanding of the current status of prevailing CPV strains in northern Africa
Mycobacterium bovis infection in cattle in Morocco: preparation and evaluation of chemical extracts for use in detection of immune responses
No full textSodium deoxycholate (DOC) was utilized to extract immunologically-active cell wall components of virulent M. bovis and M. avium, isolated from cattle in Morocco and M. fortuitum as well as related organisms e.g., N. asteroides and R. equi. The extracts from M. bovis, N. asteroides, M. fortuitum, and M. avium, were fractionated by size exclusion chromatography using Sephadex S-200. Two fractions (1 and 2) were obtained at absorbance of 280 nm. Fraction 1 of M. bovis, M. avium, M. fortuitum and of N. asteroides and nonfractionated DOC extract of R. equi elicited delayed-type hypersensitivity responses in homologously or heterologously sensitized guinea-pigs. Significant enzyme-linked immunosorbent assay values were obtained using sera from cattle 4 weeks after sensitization with homologous bacterial preparations (p < 0.01). Significant ELISA cross-reactions were observed in M. bovis or M. avium sensitized calves, using heterologous antigens;Mycobacteriologic examinations conducted on tissues collected from 246 cows in 5 major abattoirs of Morocco, revealed that M. bovis was isolated from 29.67% of the cattle examined. Mycobacteria other than M. bovis (MOTT) were isolated from tissues of 23 carcasses (9.34%). Three had lesions compatible with tuberculosis; M. bovis was not isolated;An indirect enzyme-linked immunosorbent assay using M. bovis PPD or M. bovis DOC fraction 1 as antigens was used for detecting antibodies in sera of cattle from which M. bovis was isolated. The sensitivity for M. bovis PPD was 76.71% and for DOC extract of M. bovis was 79.45%; the specificity was of 90% and 92%, respectively. These values are similar to those achieved by the tuberculin skin test (71);Investigations conducted on five selected herds in Morocco using the cervical intradermal tuberculin test and ELISA revealed that cattle in three herds were tuberculous. The comparative cervical tuberculin test using M. bovis and M. avium PPD's at equal concentration was conducted within 24 hours of a positive or suspect skin response; no reactors were identified in the remaining two herds;Combination of ELISA and tuberculin skin test conducted on animals from tuberculous herds was found to be more sensitive than either test conducted alone.</p
Low cost manufacturing of light trapping features on multi-crystalline silicon solar cells : jet etching method and cost analysis
No full textThesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (p. 127-128).An experimental study was conducted in order to determine low cost methods to improve the light trapping ability of multi-crystalline solar cells. We focused our work on improving current wet etching methods to achieve the desired light trapping features which consists in micro-scale trenches with parabolic cross-sectional profiles with a target aspect ratio of 1.0. The jet etching with a hard mask method, which consists in impinging a liquid mixture of hydrofluoric, nitric and acetic acids through the opening of hard mask, was developed. First, a computational fluid dynamics simulation was conducted to determine the desired jet velocity and angle to be used in our experiments. We find that using a jet velocity of 3 m/s and a jetting angle of 45° yields the necessary flow characteristics for etching high aspect ratio features. Second, we performed experiments to determine the effect of jet etching using a photo-resist mask and thermally grown silicon oxide mask on multiple silicon substrates : , , and multi-crystalline silicon. Compared to a baseline of etching with no jet, we find that the jet etching process can improve the light trapping ability of the baseline features by improving their aspect ratio up to 65.2% and their light trapping ability up to 38.1%. The highest aspect ratio achieved using the jet etching process was 0.62. However, it must be noted that the repeatability of the results was not consistent: significant variations in the results of the same experiment occurred, making the jet etching process promising but difficult to control. Finally, we performed a cost analysis in order to determine the minimum efficiency that a jet etching process would have to achieve to be cost competitive and its corresponding features aspect ratio. We find that a minimum cell efficiency of 16.63% and feature aspect ratios of 0.57 are necessary for cost competitiveness with current solar cell manufacturing technology.by Amine Berrada Sounni.S.M.in Technology and PolicyS.M
Migrant Necropolitics at the Table: Civilized Cannibalism in Mahi Binebine\u27s \u3cem\u3eCannibales\u3c/em\u3e
No full textIn Cannibales, the Maghrebi Francophone author Mahi Binebine revisits the encounter between the so-called “cannibals” and the European colonizer in the context of illegal immigration where bodies become commodities exchangeable for social improvements creating a different form of cannibalism. It is no longer the usual dichotomy between the civilized and the savage that is at work but rather a “civilized” European imperialist who feeds himself on a migrant’s flesh. This article argues that this representation works as a “colonial fragment” from the past but contextualized in today’s globalization. Binebine’s morbid depiction of an ambivalent postcolonial cannibalistic encounter translates as a representation of migrants in terms of cannibalistic necropolitics. The illegal migrant has no choice but to be swallowed by a narcissistic exocannibalism which seeks to incorporate what it feeds on to a total unity suggesting a bleak future not only for illegal migrants but for globalization as possibly devouring itself
Ligophorus hamzati Hafidi & Diamanka & Rkhami & Pariselle 2013, n. sp.
No full textLigophorus hamzati n. sp. (Fig. 5) TYPE MATERIAL. — Holotype MNHN HEL315; paratypes MNHN (9) HEL316, BMNH (10) 2012.12.17.4. MATERIAL EXAMINED. — 30 specimens mounted in ammonium picrate-glycerol. TYPE HOST. — Liza grandisquamis (Mugilidae). SITE OF INFECTION. — Gills, between secondary gill lamellae. TYPE LOCALITY. — Grand Lahou Lagoon, Ivory Coast (5°08’11”N, 5°01’33”E). ETYMOLOGY. — Hamzati is given for Hamzat, name of the son of the first author of this article. FIG. 5. – Ligophorus hamzati n. sp.: morphological structures as in Fig. 1. Abbreviations: see Material & Methods. Scale bar: 30 µm. DESCRIPTION Flattened adult, 580 ± 33 (410-537) [30] long and 80 ± 10 (65-116) [30] wide at gonad level, pharynx: 26 (20-33) [28] larger diameter. Haptor well demarcated with 14 marginal hooks: 13 ± 0.9 (8-17) [360] long. Dorsal anchor with guard two time longer than shaft: a = 43 ± 4 (34-50) [60]; b = 34 ± 3 (28-39) [60]; c = 6 ± 0.7 (4-7) [60]; d = 13 ± 1.5 (9-16) [60]; e = 7 ± 0.8 (6-9) [60]. Dorsal bar V-shaped: 20 ± 2 (17-24) [30] long, 4 ± 0.7 (3-6) [30] wide and 7 ± 1.1 (5-10) [30] high. Ventral anchor: a = 42 ± 2 (36-45) [60]; b = 34 ± 2 (31-37) [60]; c = 7 ± 0.8 (5-10) [60]; d = 11 ± 1.3 (8-14) [60]; e = 7 ± 0.6 (6-9) [60]. Ventral bar, 39 ± 3 (32-47) [30] long and 9 ± 2 (6-13) [30] wide, with small antero-median protuberance and two lateral and symmetrical expansions: 10 ± 3 (4-18) [30] apart. MCO as copulatory tube: 92 ± 6 (81-100) [30] long, passes through a tubular accessory piece, 48 ± 7 (38-59) [30] long, with bifurcated distal extremity, each branches bifurcated also. Vagina: 51 ± 10 (21-67) [30] long. REMARKS This species is distinguished from all Ligophorus species by the shape of the accessory piece of the copulatory organ, which is bifurcated two times at its distal extremities. DISCUSSION The co-existence of fish hosts with a great difference in Ligophorus species richness is not exceptional. Euzet & Suriano (1977) observed only one species (Lig. angustus Euzet & Suriano, 1977) from Chelon labrosus (Risso, 1827) in the Mediterranean Sea, whereas the other mullet species may be parasitized by at least two species. Six species were reported from Liza carinata by Dmitrieva et al. (2012) and from Liza subviridis by Soo and Lim (2012), and at least 14 species were reported from M. cephalus by Dmitrieva et al. (2012). Similar differences in monogenean species richness were reported from cichlid hosts in West Africa by Pariselle et al. (2003). These authors drew a parallel between parasite species richness and host genetic diversity, which were both shaped by fluctuations of host populations through bottleneck or vicariant events. Therefore, in the case of Ligophorus from studied African mugilids, only the population of Liza bandialensis, which is endemic to a very limited area in Senegal, may have suffered numerous bottleneck events, leading to reductions in its size, and in turn to the loss of all its monogenean parasites. Among the three other widely distributed Liza species in Africa, Liza falcipinnis, which was infected by only one Ligophorus species, may have had a more stable history (and thus, a lower genetic and parasitic diversity) when compared to Liza grandisquamis, which was infected by three Ligophorus species and Liza dumerili, which according to Berrada Rkhami et al. (1993) was infected by over ten Ligophorus species.Published as part of Hafidi, Fouzia El, Diamanka, Arfang, Rkhami, Ouafae Berrada & Pariselle, Antoine, 2013, New species of Ligophorus (Monogenea, Ancyrocephalidae), parasite of Liza spp. (Teleostei, Mugilidae) off the Northwestern African coast, pp. 215-225 in Zoosystema 35 (2) on pages 222-224, DOI: 10.5252/z2013n2a6, http://zenodo.org/record/516044
Étude séro-épidémiologique des principales maladies infectieuses abortives chez la vache laitière au Maroc
No full textDans le but de déterminer l'importance des avortements et la séroprévalence de six infections abortives à savoir la brucellose, la leptospirose, la néosporose, la fièvre Q, la salmonellose et l'infection par l'herpèsvirus bovin 4 (BoHV-4) chez les vaches laitières au Maroc, une enquête séro-épidémiologique a été menée au niveau de cinq grands élevages des régions de Fès et du Gharb au Maroc, où des avortements ont souvent été signalés. Un total de 252 sérums a été collecté à partir de femelles de différents âges et une enquête rétrospective, se basant sur des questionnaires et sur les registres des exploitations, a été réalisée sur un total de 4144 femelles entre 2018 et 2022. Des anticorps dirigés contre les agents pathogènes étudiés ont été détectés par des tests ELISA indirecte dans 75,7 % des échantillons testés, avec une séroprévalence globale de 46% pour Leptospira hardjo, 25% pour Neospora caninum, 43% pour Coxiella burnetii, 50% pour le BoHV-4. Quant à Salmonella, des anticorps contre le sérovar Dublin ont été identifiés dans deux élevages avec une séroprévalence moyenne de 2%. Les indicateurs sérologiques de co-infections étaient fréquemment observés. L'absence d'évidence de facteurs non infectieux épidémiologiquement liés aux avortements suggère que les agents étudiés doivent être considérés comme des facteurs de risque importants dans la dynamique du syndrome observé, même si des investigations complémentaires sont nécessaires pour identifier les causes de l'avortement.
Mots clés: Maladies abortives, brucellose, leptospirose, néosporose, la fièvre Q, salmonellose, herpèsvirus bovin 4, Maro
Pathogénicité de l\u27adénovirus aviaire sérotype 11 sur les embryons de poulet exempts d\u27agents pathogènes spécifiques
No full textInclusion body hepatitis (IBH) associated with fowl aviadenovirus (FAdV) infection has a world-wide distribution, especially for broilers aged 3 to 5 weeks, causing significant economic losses to poultry industry. In present study, we evaluated the pathogenicity of Moroccan FAdV serotype 11 (MOR111115 strain) in specific pathogen free (SPF) white leghorn chicken embryos. FAdV (titre 10?/ml) was inoculated to SPF embryonated chicken eggs through the chorioallontoic membrane (CAM). The mortality, gross and microscopical lesions of the embryos were evaluated and the presence of the virus was checked by PCR. 100% cumulative embryonic mortality was observed at 7 days post-infection (dpi). The inoculated embryos were hemorragic and the liver was friable and swollen, with yellow to greenish discoloration. Microscopically, we highlighted a multifocal necrosis of hepatocytes groups with the presence of basophilic and eosinophilic intra-nuclear inclusion bodies within hepatocytes. The presence of the virus was confirmed by conventional polymerase chain reaction based on hexon gene from liver.that is a major target organ of FAdV infections. This is the first study of pathogenicity of fowl aviadenovirus in SPF chicken embryos in Morocco.
Keywords: Fowl aviadenovirus-11, Inclusion body hepatitis, Pathogenicity, Chicken embryosL\u27hépatite à corps d\u27inclusion (IBH) associée à l\u27infection par l\u27aviadénovirus aviaire (FAdV) a une distribution mondiale, en particulier chez les poulets de chair âgés de 3 à 5 semaines, entraînant des pertes économiques importantes de l\u27industrie avicole. Dans la présente étude, nous avons évalué la pathogénicité du virus FAdV- sérotype 11 isolé au Maroc (souche MOR111115) chez les embryons de poulets exempts d’agent pathogène (SPF). Le FAdV (titre 10? / ml) a été inoculé à des œufs embryonnés SPF à travers la membrane chorioallontoique (CAM). La mortalité, les lésions macroscopiques et microscopiques des embryons ont été évaluées et la présence du virus a été confirmé par réaction de polymérisation en chaine (PCR). La mortalité embryonnaire cumulative de 100% a été observée 7 jours après l\u27infection (dpi). Les embryons inoculés étaient hémorragiques et le foie était hypertrophié et friable, avec une décoloration jaune à verdâtre. Au microscope, nous avons mis en évidence une nécrose multifocale des groupes d\u27hépatocytes avec la présence de corps d\u27inclusion intra-nucléaires basophiles et éosinophiles dans les hépatocytes. La présence du virus a été confirmée par PCR conventionnelle basée sur le gène hexon à partir des prélèvements du foie, qui constitue l’organe cible des infections à FAdV. Il s\u27agit de la première étude de la pathogénicité de l\u27aviadénovirus aviaire dans les embryons de poulet SPF au Maroc.
Mots clés: Adénovirus aviaire, Hépatite à corps d’inclusion, Pathogénicité, Embryon de poule
Atypical cerebral MRI imaging findings in a patient with isolated neurosarcoidosis
No full textSarcoidosis is a rare, chronic, granulomatous disease of unknown etiology and primarily effects the lymphatic and respiratory systems. The central nervous system (CNS) is unusually implicated in sarcoidosis patients. We describe a rare magnetic resonance imaging (MRI) findings in a case of isolated neurosarcoidosis. The evaluation of suspect patients requires radiological imaging studies, especially MRIs. The diagnosis of neurosarcoidosis is clinically challenging, MRI studies are effective in detecting CNS inflammation but lack specificity
SPARK : an educator\u27s look at connection in 21st century American schools
No full textConnection, creativity in the classroom and miracles are possible, even in today\u27s standardized climate. The author gives examples that prove damaged systems can be overcome and difficult situations surmounted. Her hope is that this integrative master\u27s project will show a true exploration of what it means to have an inner voice, to find and free it, and eventually express it
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