Disbond Detection and Characterization Using Horizontally Polarized Shear Waves and EMAT Probes

Horizontally polarized shear waves offer high sensitivity for inspection of adhesively bonded structures. They produce a strong shear deformation on the adherent-adhesive interface allowing a relatively direct estimation of the adhesive failure (disbonds). Compared to localized conventional point-by-point ultrasonic waves, horizontal shear guided waves can be launched over long distances and larger areas of structural parts can be covered. Guided horizontal shear waves have a multimodal character and do not exhibit mode conversion at interfaces. The first fundamental symmetric shear mode (HS0) propagates non-dispersively in isotropic materials, while higher orders modes are dispersive and behave as guided Lamb waves

Epidemiological and molecular assessment of a rubella outbreak in North-Eastern Italy

International audienceFrom January to June 2008, a rubella outbreak involving 111 laboratory confirmed cases occurred in the Friuli Venezia Giulia (FVG) region of North-Eastern Italy. The outbreak occurred initially in two residential homes for young adults disabled mentally and physically. Subsequently, the epidemic spread to the general population. Young adult cohorts were mostly affected and the mean age of the patients was 26.8 years; the majority of cases were male (73.8%), with a mean age of 26.6 years in males and 27.4 in females. Three pregnant women had a primary infection and two had their pregnancies terminated. Genotyping of sixteen isolates showed the circulation of RUBV 2B, a genotype originating from Asia and South Africa and now present in Europe. In addition, molecular analysis revealed a well defined space-temporal spread of two viruses showing distinct sequences. A seroepidemiological survey carried out in a city within the same geographical area showed that the proportion of women of childbearing age still susceptible to rubella virus was 5.5%, fairly close to the figure (less than 5%) expected by 2010

Epidemic History and Evolutionary Dynamics of Hepatitis B Virus Infection in Two Remote Communities in Rural Nigeria

BACKGROUND: In Nigeria, hepatitis B virus (HBV) infection has reached hyperendemic levels and its nature and origin have been described as a puzzle. In this study, we investigated the molecular epidemiology and epidemic history of HBV infection in two semi-isolated rural communities in North/Central Nigeria. It was expected that only a few, if any, HBV strains could have been introduced and effectively transmitted among these residents, reflecting limited contacts of these communities with the general population in the country. METHODS AND FINDINGS: Despite remoteness and isolation, approximately 11% of the entire population in these communities was HBV-DNA seropositive. Analyses of the S-gene sequences obtained from 55 HBV-seropositive individuals showed the circulation of 37 distinct HBV variants. These HBV isolates belong predominantly to genotype E (HBV/E) (n=53, 96.4%), with only 2 classified as sub-genotype A3 (HBV/A3). Phylogenetic analysis showed extensive intermixing between HBV/E variants identified in these communities and different countries in Africa. Quasispecies analysis of 22 HBV/E strains using end-point limiting-dilution real-time PCR, sequencing and median joining networks showed extensive intra-host heterogeneity and inter-host variant sharing. To investigate events that resulted in such remarkable HBV/E diversity, HBV full-size genome sequences were obtained from 47 HBV/E infected persons and P gene was subjected to Bayesian coalescent analysis. The time to the most recent common ancestor (tMRCA) for these HBV/E variants was estimated to be year 1952 (95% highest posterior density (95% HPD): 1927-1970). Using additional HBV/E sequences from other African countries, the tMRCA was estimated to be year 1948 (95% HPD: 1924-1966), indicating that HBV/E in these remote communities has a similar time of origin with multiple HBV/E variants broadly circulating in West/Central Africa. Phylogenetic analysis and statistical neutrality tests suggested rapid HBV/E population expansion. Additionally, skyline plot analysis showed an increase in the size of the HBV/E-infected population over the last approximately 30-40 years. CONCLUSIONS: Our data suggest a massive introduction and relatively recent HBV/E expansion in the human population in Africa. Collectively, these data show a significant shift in the HBV/E epidemic dynamics in Africa over the last century

UT with SH-Waves and Electromagnetic Ultrasonic (EMUS) -Transducers

In the ultrasonic testing practice of today SV- and longitudinal waves are exclusively used because these wave types can be excited by piezoelectric ultrasonic transducers introduced a long time ago.</p

Inter-population variability of Longidorus euonymus Mali and Hooper, 1974 (Nematoda, Dorylaimida) and comment upon the number of juvenile developmental stages

Longidorus euonymus is distributed widely in central and southern Europe. Nematodes typically have four pre-adult stages, however, there has been confusion in the scientific literature with regard to the number of juvenile developmental stages (JDS) of L. euonymus with three and four JDS being reported. A principal component analysis of published morphometric data from 33 L. euonymus populations unequivocally showed that there were four juvenile developmental stages. Furthermore, 18S rDNA sequence analysis indicated that L. euonymus was more closely related to L. elongatus and L. attenuatus than to L. vineacola. This was in discordance with the original description of the species; however, the maximum likelihood distances between the species were relatively small