Comparison of methods to enumerate bacteria in dental unit water lines

Millipore HPC samplers are simple, self-contained test devices that can be used by personnel in dental offices who do not have microbiologic training to easily and economically monitor dental unit water quality without laboratory support. This study evaluated the correlation of HPC samplers to R2A agar for enumerating planktonic bacteria in dental unit treatment water. Eight different dental units were sampled. Five replicates were performed for each media at each dilution. The Pearson correlation coefficient between the R2A agar and HPC sampler is 0.89. These data suggest HPC samplers correlate with conventional laboratory-based R2A culture techniques for determining dental unit water line contamination.     

Structural Features and Transport Properties of La(Sr)Fe1-xNixO3-δ– Ce0.9Gd0.1O2-δ Nanocomposites—Advanced Materials for IT SOFC Cathodes

Mixed ionic?electronic conducting nanocomposites comprising complex oxides - perovskite (lanthanum-strontium nickelate-ferrite [LSFN]) and gadolinium-doped ceria (GDC) have been prepared via ultrasonic dispersion of nanocrystalline powders of LSFN_x and GDC in organic solvent with addition of surfactant, followed by drying and sintering up to 1300°C. Their structural and surface properties have been studied by x-ray diffraction, ultraviolet–visible (UV-vis) electron spectroscopy, transmission electron microscopy with elemental analysis, and x-ray photoelectron spectroscopy. Results of impedance spectroscopy, oxygen isotope exchange, O₂ temperature-programmed desorption, weight, and conductivity relaxation experiments have revealed a strong positive effect of perovskite?fluorite nanodomain interfaces in composite on the oxygen mobility and reactivity. Testing in wet H₂/air feeds for a button-size cell with functionally graded LSFN_0.4–GDC cathode layer supported on a thin YSZ layer covering Ni/YSZ cermet has demonstrated high and stable performance, promising for the practical application in the intermediate temperature range.     

Acquired deafness: a multi-dimensional experience

The aim of this study was to investigate the subjective experience of acquired deafness using quantitative (questionnaire) and qualitative (interview) methods. This paper presents findings from the questionnaire data. Eighty-seven people (of whom 38 had acquired a profound loss) participated in the study. The questionnaire contained items designed to examine both audiological and non-audiological aspects of deafened people's experiences. It also sought to measure the extent to which those aspects affect their quality of life. The questionnaire included three variables (i.e. reported frequency and impact of depression, and overall effect of deafness on one's life) as broad indicators of adjustment. Seventy-three respondents (including all but one of the profound group) completed the questionnaire. Factor analysis of the questionnaire data identified six major themes (with variance > 10%) underlying the personal experience of acquired deafness. Three themes--communicative deprivation, restriction, and malinteraction by hearing people--dealt with observable aspects of respondents' experience. Multiple regression found that these factor themes associated with biomedical variables. The remaining three themes dealt with less tangible aspects of the deafness experience. These themes--feelings of distress in interaction, feelings of abandonment and benefit from positive experiences--did not associate with biomedical variables. Finally, multiple regression indicates that respondents' factor scores predict the impact of deafness at least as strongly as their audiological and social characteristics.     

PCR analysis of microsatellite DNA markers: possibility of erroneous determination of genotypes

A comparative study of two techniques for the PCR genotyping of highly polymorphic tandem repeats was carried out by the example of a triplet repeat in the myotonin protein kinase gene. Sequencing denaturing gels were shown to yield more precise results in the analysis of amplification products.     

Estimating Basic Characteristics of Arrival Processes in Telecommunication Networks by Empirical Data

Considering the realistic teletraffic analysis in advanced telecommunication networks, the estimation of basic characteristics of arrival processes by empirical data is an important subject of current research. Using independent observations of the interarrival times between events and the mean numbers of events in intervals of fixed length, we propose methods to estimate the intensity of a nonhomogeneous arrival stream, particularly a Poisson process, and the renewal function of a renewal process. We formulate the estimation task as stochastically ill-posed problem and apply procedures for the stabilization of the estimates.     

Human T-cell receptor V beta gene polymorphism and multiple sclerosis

Population-based genetic associations have been reported between RFLPs detected with probes corresponding to the genes encoding the beta chain of the T-cell receptor for antigen (TCRB) and a variety of autoimmune disorders. In the case of multiple sclerosis (MS), these studies have localized a putative disease-associated gene to a region of approximately 110 kb in length, located within the TCRB locus. In the current study, all 14 known TCRBV (variable region) genes within the region of localization were mapped and identified. The nucleotide sequences of these genes were determined in a panel of six MS patients and six healthy controls, who were human-leukocyte antigen and TCRB-RFLP haplotype matched. Nine of the 14 TCRBV genes studied showed evidence of polymorphism. PCR-based assays for each of these polymorphic genes were developed, and allele and genotype frequencies were determined in a panel of DNA samples from 48 MS patients and 60 control individuals. No significant differences in allele, genotype, or phenotype frequencies were observed between the MS patients and controls for any of the 14 TCRBV-gene polymorphisms studied. In light of the extensive linkage disequilibrium across the region studied, the saturating numbers of polymorphisms examined, and the direct sequence analysis of all BV genes in the region, these results suggest that it is unlikely that germ-line polymorphism in the TCRBV locus makes a major contribution to MS susceptibility.(ABSTRACT TRUNCATED AT 250 WORDS)