Influence d'une infection expérimentale à Trypanosoma congolense sur la fonction sexuelle des béliers Djallonké et Sahéliens en zone subhumide

Influence of an experimental Trypanosoma congolense infection on the reproductive function of Djallonké and Sahelian rams in subhumid zone. To measure the effect of African animal trypanosomosis (AAT) on male reproductive function, eight 18-24 month old Djallonké (ID; 31.2 ± 2.95 kg) and Sahelian (IS; 41.7 ± 4.64 kg) rams were infected with 104 Trypanosoma congolense. Eight other Djallonké (CD) and Sahelian (CS) rams with similar bodyweight and ages were used as uninfected controls. Four weeks after infection, ID and IS were treated with a trypanocidal drug, while maintained under observation. The evolution of clinical parameters shows a higher aptitude of Djallonké than Sahelian to control the effects of infection. This interbreed difference in susceptibility to AAT was confirmed by the higher weight losses in IS (-31.3 g) when compared to ID (-12.8 g) as to CD and CS rams. The effect of a T. congolense infection consisted in a decreased libido in IS (33 s) when compared to ID (22.1 s) (P > 0.05). The results indicate a significant effect of breed on ejaculate volume (CS: 1.23 ml vs CD: 0.88 ml; P < 0.05). Otherwise, breed did not significantly affect the other spermatic parameters. CD sperm cells concentration (3,293.4 x 106.ml-1), total abnormality rate (15.3%), dead sperm cells rate (13.9%), mobile sperm cells rate (75.5%), individual (3.76) and mass motilities (3.94) did not differ (P > 0.05) from those of CS (respectively 3,481.7 x 106.ml-1; 17.3%; 12.4%; 74.9%; 3.77; 3.36). However, the later produced 26% more total sperm cells than CD (P > 0.05). The infection reduced ejaculate volume by 15.8 and 14.5%, (P > 0.05), production of total sperm cells by 18.2 and 13.3% (P > 0.05) and the rate of mobile sperm cells by 14.2 and 27.9% (P < 0.05) respectively for Djallonké and Sahelian rams. The results show a dysfunctional state of testicles due to the harmful effects of AAT infection, hence the increase in dead sperm cells by 69.8 and 74.3% (P > 0.05) and in the rate of total abnormal sperm cells by 23.6 and 24.1% (P > 0.05) respectively for ID and IS rams when compared respectively to CD and CS animals. Harmful effects often more pronounced in Sahelian breeds during this experiment could indicate a higher susceptibility of this breed to AAT in comparison with Djallonké. One Sahelian ram died two weeks post-infection and azoospermia was observed in another one six weeks after chemotherapy and the disappearance of parasites from the bloodstream

Traitements ethno-vétérinaires des parasitoses digestives des petits ruminants dans le plateau central du Burkina Faso

La présente étude visait d\'une part, à mieux comprendre les motivations des éleveurs à recourir aux méthodes traditionnelles de soins pour leurs animaux, et d\'autre part, à recenser les remèdes utilisés dans la région du plateau central du Burkina Faso. Elle s\'est déroulée de juin à octobre 2006 en deux étapes : i) une phase de groupe (focus-group screening) avec un formulaire-guide d\'entretien comme support d\'interview semi-structurées (ISS) auprès de 101 éleveurs et ii) une phase individuelle sous la forme d\'enquêtes formelles avec un formulaire administré successivement à 21 tradipraticiens vétérinaires reconnus compétents dans le traitement des parasitoses digestives des petits ruminants par la communauté des éleveurs. Les résultats ont montré que 50.5% des éleveurs utilisaient concomitamment la médecine vétérinaire moderne et celle traditionnelle pour soigner les animaux malades. Les tradipraticiens vétérinaires qui prestent pour ces éleveurs sont âgés en moyenne de 57,6 ans et sont analphabètes. Les remèdes traditionnels proposés pour lutter contre les parasites digestifs des petits ruminants de la région sont essentiellement à base de plantes locales (88,8%) composées de douze (12) espèces appartenant à neuf (9) familles botaniques. Leurs modes de préparation et d\'administration aux animaux sont décrits selon les dires des tradipraticiens enquêtés. Keywords: Pharmacopée vétérinaire; parasites digestifs; petits ruminants; région centrale, Burkina Faso. International Journal of Biological and Chemical Sciences Vol. 1 (3) 2007: pp. 397-30

Antistatic polymer materials

ABSTRACT: Introduction. In connection with the growing demand for living and working conditions in civil and industrial construction, there is an increasing need for high-quality building materials with the required set of performance properties. Polymer reinforced composite materials are promising materials in the construction industry due to their high strength, durability, reliability and economy. Polymers such as polyvinyl chloride, polyurethanes, polyacrylates, epoxy resins, polypropylene are used in construction for the manufacture of decorative elements, self-leveling floors, coatings for appliances and equipment. However, the use of polymeric materials creates risks of electric shock due to the generation of static charge. The use of electrically conductive nanomaterials as fillers makes it possible to reduce the resistivity of polymeric materials and slow down the flow of electric charges. Main part. This review article presents the benefits and drawbacks of antistatic additives for polymer materials used in industry and in the construction industry. Conclusion. An analysis of the literature has shown that over the past seven years, the largest number of relevant papers has been devoted to carbon materials as antistatic additives (8 articles), metal and metal oxide nanoparticles (7 articles), ionic liquids (7 articles), and polyaniline (7 articles). The most studied characteristics of antistatic polymer materials are the specific surface RS and volume RV resistances. According to the reviewed articles, metal and metal oxide nanoparticles are the most suitable antistatic additives to polymeric materials, since they are well dispersed in the polymer matrix. However, further research is needed to eliminate the negative effect of nanoparticles on the mechanical properties of polymeric material

Morphological assessment of Niger Kuri cattle using multivariate methods

A total of 406 adult cows and 34 bulls belonging to the Niger Kuri cattle population were assessed for 16 body measurements and 11 qualitative traits to contribute to the characterization of this unique cattle breed. Body measurements included facial, horn, ear and rump lengths; facial, cranial, shoulder, pelvic and ischium widths; height at withers and at hips; muzzle circumference; heart girth; body and tail lengths; and thorax depth. Qualitative traits included cephalic profile, ear shape, muzzle pigmentation, eyelid pigmentation, hoof pigmentation, horn colour, dewlap size, backline profile, horn shape, spotting pattern, and coat colour pattern. Data were analysed jointly with 377 individuals from four other West African taurine cattle breeds (N’Dama, Lagunaire, Lobi and Somba) using multivariate statistical methods, including canonical and correspondence analyses. Among the breeds analysed, Kuri cattle had the highest mean values for all body measurements: height at withers and body length had mean values of 124.0 ± 0.4 and 146.8 ± 1.0 cm in Kuri cows, respectively, and 126.0 ± 2.2 and 155.7 ± 3.6 cm, respectively, in Kuri bulls. Canonical analysis allowed the construction of contour plots to illustrate the high differentiation between Kuri cattle and the other breeds, regardless of the sex of the individuals. Further, the Mahalanobis distance matrices showed that pairs involving Kuri cattle had the higher differentiation of these populations. Correspondence analysis carried out on these 11 qualitative traits allowed the researchers to ascertain a clear differentiation between the Kuri and the other taurine cattle breeds. The N’Dama, Lagunaire, Lobi, and Somba breeds did not show clear differentiation at qualitative-type trait level with 75% confidence regions computed for these four breeds being highly intermingled. In the current data, Kuri cattle had the highest frequency in qualitative features, such as concave cephalic profile, dropped ears, non-pigmented muzzle and grey-coloured horns, which are absent in West African taurine and zebu cattle breeds, according to the literature. The current evidence would suggest that unique Kuri cattle type features may result from breeding decisions rather than from zebu admixture. This work confirms that at type trait level Kuri cattle is a unique population within the West African taurine cattle group. The implementation of genetic analyses aiming at ascertaining the degree of uniqueness of the breed is advised.Keywords: Body measurements, Bos taurus, multivariate analyses, qualitative traits, West African cattl

Meningococcal carriage and cerebrospinal meningitis after MenAfriVac mass immunization in Burkina Faso

The aims of this study were to evaluate the impact of conjugate vaccine A, MenAfriVac, on Neisseria meningitidis (Nm) asymptomatic carriage and cerebrospinal meningitis in three health districts (Bogodogo, Kaya, and Dandé) of Burkina Faso. Asymptomatic carriage of Nm was assessed by performing cross-sectional studyrepeated (rounds 1 to 10) before and after introduction of the conjugate vaccine against serogroup A of N. meningitidis (NmA), MenAfriVac. In each round at least 1,500 people were enrolled in each district for a month. Data oncases of meningococcal meningitis in the three studied health districts were collected through meningitides epidemiological surveillance of Burkina Faso.Nm was identified in680 of 23,885 throat swabs before vaccination (2. 84%)withNmYasthe dominant serogroup(1.87%). During the same period (2009 and 2010), 891 cases of suspected meningitis were reported in the three health districts among whom 42 were due toNm (4.71%) withNmX (3.70%) asthe most frequently identified serogroup. After vaccination, Nm was identified in 1117 of 27,245 pharyngeal samples (6.42%); NmX (4.42%) wasthe dominantserogroup. From 2011 to 2013, 965 cases of suspected meningitis were reported in all health facilities in the three studied health districts located in the geographical study area; 91 was due toNm (9.43%) andNmWasthe most commonserogroup(52 cases= 5.38%).After introduction of conjugate vaccine A (MenAfriVac), the NmAserogroup almost disappeared both in asymptomatic carriers and in patients with cerebrospinal meningitis. However the presence of the NmW and NmXserogroups, which appear to have replaced serogroup A, is very worrying with regard to meningitis prevention and control in Burkina Faso. It appears necessary to strengthen surveillance and laboratory diagnosis of the different meningococcal serogroups circulating in Africa.Keywords: meningococcal meningitis, serogroups W and X, meningococcal carriage, MenAfriVac

Direct detection of shigella in stool specimens by use of a metagenomic approach

The underestimation of Shigella species as a cause of childhood diarrhea disease has become increasingly apparent with quantitative PCR (qPCR)-based diagnostic methods versus culture. We sought to confirm qPCR-based detection of Shigella via a metagenomics approach. Three groups of samples were selected from diarrheal cases from the Global Enteric Multicenter Study: nine Shigella culture-positive and qPCR-positive (culture+ qPCR+) samples, nine culture-negative but qPCR-positive (culture- qPCR+) samples, and nine culture-negative and qPCR-negative (culture- qPCR-) samples. Fecal DNA was sequenced using paired-end Illumina HiSeq, whereby 3.26 × 108 ± 5.6 × 107 high-quality reads were generated for each sample. We used Kraken software to compare the read counts specific to Shigella among the three groups. The proportions of Shigella-specific nonhuman sequence reads between culture+ qPCR+ (0.65 ± 0.42%) and culture- qPCR+ (0.55 ± 0.31%) samples were similar (Mann-Whitney U test, P = 0.627) and distinct from the culture- qPCR- group (0.17 ± 0.15%, P \u3c 0.05). The read counts of sequences previously targeted by Shigella/enteroinvasive Escherichia coli (EIEC) qPCR assays, namely, ipaH, virA, virG, ial, ShET2, and ipaH3, were also similar between the culture+ qPCR+ and culture- qPCR+ groups and distinct from the culture- qPCR- groups (P \u3c 0.001). Kraken performed well versus other methods: its precision and recall of Shigella were excellent at the genus level but variable at the species level. In summary, metagenomic sequencing indicates that Shigella/EIEC qPCR-positive samples are similar to those of Shigella culture-positive samples in Shigella sequence composition, thus supporting qPCR as an accurate method for detecting Shigella

Sheet Molding Compound Automotive Component Reliability Using a Micromechanical Damage Approach

The mastering of product reliability is essential for industrial competitiveness. If for metallic materials the topic is well-known, especially in automotive industry, Original Equipment Manufacturers are expecting strong support of their suppliers to full-fill the lack data. This paper presents a new original approach, using a micromechanical based on damage model to address the problem of reliability of Sheet Molding Compound (SMC) components. The first part demonstrates the inadequacy of the standard method of reliability on SMC material through its application on the new Peugeot 3008. In fact, the very flat S-N curve of SMC, and in general, composite materials is not appropriate for acceleration effect. The proposed model correlates the stress, damage and strength with both cycle number and slamming velocity. It emphasizes the relation between the effective distribution with the slamming velocity effect. Then, a new reliability approach based on a micromechanical fatigue/damage model was developed. The definition of new probability distributions based on damage was necessary to apply properly the stress-resistance approach. It allows taking into account the velocity effect by switching in damage space. Finally, applying this new methodology on the Peugeot 3008, leads to the definition of the optimal validation laboratory tests to ensure the reliability. Indeed, the required number of cycles to ensure reliability has been reduced significantly. Micromechanical damage reliability approach could be an efficient way to ensure the reliability of short fiber reinforcement composite components used in industrial context.Authors address a strong acknowledgment to E. FEIGE and Y. HAMOY, from PSA, for the data provided. Their comments and advices were also very useful.We are grateful to Mr. OZOUF for teaching and advices on the general topic of reliability