Analyse des résonateurs diélectriques anisotropes uniaxiaux par la méthode du raccordement modal

In this paper, an extension of the mode matching method to the analysis of uniaxial anisotropic dielectric resonators is presented. The study will focus on the dominant TE_01δ though an extension to higher order modes is straightforward. The dependency of the dominant mode resonant frequency on the anisotropy parameters is analyzed in detail. Numerical results are in a very good agreement with the literature.     

Migratory behaviour and desiccation tolerance of protostrongylid nematode first-stage larvae

Migration of first-stage larvae (L1) from faeces to soil is a crucial stage in the life-history of protostrongylids transmitted via land snails. Migration of Muellerius cf. capillaris and a Cystocaulus sp. L1 from fresh Nubian ibex (Capra ibex nubiana) faeces (48-50% water content, W.C.) to substrate soils (at 100% r.h., 26 degrees C) was measured experimentally using dry (3 +/- 1% W.C.), wet (31 +/- 0.43% W.C.) and flooded (48.4 +/- 2.45% W.C.) soils. The highest migration rates (90.4 +/- 1.6% migration) in both species occurred on flooded soils when the faecal pellet W.C. reached 90%. The next highest migration rates (43.2 +/- 3.6% migration, at 60% faecal W.C.) were on the wet soils and no migration occurred on dry soil or dry-substrate papers. Migration rates did not differ significantly (P > 0.05) between species. Active Theba pisana were not infected by M. cf. capillaris L1 on dry infested soils, but were infected following rehydration of the same soils. By day 10, L1 of M. cf. capillaris demonstrated lower survival rates in water and in 97% and 76% r.h. (74.5%, 15.2% and 1.9%, respectively) than the Cystocaulus sp. (97.5%, 43.8%, 43.3%) and Protostrongylus sp. (97.9%, 43.2%, 23.8%, P < 0.05). All three nematodes had a remarkably high survival rate (> 99% overall survival, by day 10) when exposed directly to 0% r.h. at 23 degrees C. Results demonstrate the ability of L1 to survive extreme desiccation through anhydrobiosis. Migration of L1 from faeces to soil can take place only during rains which coincide with peak activity of land snails in desert habitat.     

A pilot study of oral sumatriptan as intermittent prophylaxis of menstruation-related migraine

Headaches associated with menstruation are often resistant to abortive and preventative medications. We performed an open-label study in 20 female migraineurs, employing oral sumatriptan perimenstrually as short-term prophylaxis of menstrual migraine. In 126 sumatriptan-treated cycles, headache was absent in 52.4% and reduced in severity by 50% or greater in 42%. Breakthrough headaches were rare and significantly reduced in severity compared with baseline headaches.     

A novel nucleic acid-binding protein that interacts with human rad51 recombinase

Using the yeast two-hybrid system, we isolated a cDNA encoding a novel human protein, named Pir51, that strongly interacts with human Rad51 recombinase. Analysis in vitro confirmed the interaction between Rad51 and Pir51. Pir51 mRNA is expressed in a number of human organs, most notably in testis, thymus, colon and small intestine. The Pir51 gene locus was mapped to chromosome 12p13.1-13. 2 by fluorescence in situ hybridization. The Pir51 protein was expressed in Escherichia coli and purified to near homogeneity. Biochemical analysis shows that the Pir51 protein binds both single- and double-stranded DNA, and is capable of aggregating DNA. The protein also binds RNA. The Pir51 protein may represent a new member of the multiprotein complexes postulated to carry out homologous recombination and DNA repair in mammalian cells.     

Relationship between phase variation in colony morphology, intrastrain variation in cell wall physiology, and nasopharyngeal colonization by Streptococcus pneumoniae

Streptococcus pneumoniae undergoes phase variation in colony morphology, which has been implicated as a factor in the pathogenesis of pneumococcal disease. Phenotypic differences between opaque and transparent colony forms correlate with differences in rates of autolysis. This study examined whether differences in autolysis are caused by differences in expression of the major amidase, LytA, or the structure of its peptidoglycan substrate. No significant difference was detected by high-pressure liquid chromatography analysis of stem peptides released after treatment of purified peptidoglycan with amidase. Differences in the rate of digestion of purified cell walls, furthermore, did not correlate with susceptibility to autolysis. Lower levels of autolysis in opaque variants, however, was associated with decreased levels of immunodetectable LytA on colony immunoblots and Western blots (immunoblots). Diminished cell-surface-associated LytA in opaque variants was also demonstrated by whole-cell inhibition enzyme-linked immunosorbent assay. Since transparent variants have been shown both to colonize the nasopharynx more efficiently in an animal model and to express more surface-exposed LytA, it was determined whether LytA contributes to colonization in a neonatal rat model of pneumococcal carriage. Defined mutants in the lytA gene were used to show that there was no significant contribution by LytA to nasopharyngeal colonization in this model. Although the expression of LytA was shown to undergo phase variation in association with colony morphology, lytA mutants are still capable of phenotypic variation in colony morphology, which suggests that other factors are responsible for intrastrain differences which affect colonization.     

Novel classes of Azospirillum brasilense mutants with defects in the assembly and functioning of polar and lateral flagella

Present paper is aimed at assessing the effect of hypoxic gaseous mixtures intended for the use as the fire suppression agents within closed volumes on the basis of argon with addition of carbonic acid on the body of mammalia. Three experiments were performed on the male white laboratory Wistar rats. It is indicated that argon adding to the hypoxic mixtures containing 4-5% volume increases animal survivability as compared to analogous nitrogen-based mixtures. An addition of 4-8% volume of carbonic acid impairs the of animal condition and reduces the survival rate. There noted a pronounced negative effect of the increased temperature on the survival time in the hypoxic media. One can draw inference about the principal possibility of using argon for formation of the hypoxic gaseous mixtures possessing fire suppression properties.     

Short peptide-based tolerogens without self-antigenic or pathogenic activity reverse autoimmune disease

An immunodominant epitope of myelin basic protein (MBP), VHFFKNIVTPRTP (p87-99), is a major target of T cells in brain lesions of multiple sclerosis (MS), and this peptide can trigger experimental autoimmune encephalomyelitis (EAE). We designed truncated peptides based on this pathogenic 13-mer that are not antigenic. These short peptides reduced production of IFN-gamma and TNF-alpha in vivo. Moreover, paraplegic rats given the 7-mer FKNIVTP in soluble form showed total reversal of paralysis in 24 h. Truncated peptides that are too small to stimulate antigenic responses to pathogenic regions of myelin basic protein are nevertheless effective tolerogens and are able to anergize autoreactive T cells. Short peptide-based tolerogens, devoid of immunogenic and pathogenic potential, may be attractive for therapy of autoimmune diseases.