A pilot survey of impression materials and techniques used by dentists in the fabrication of fixed indirect restorations

Objective: To assess the choice of impression material and impression technique used by Nigerian dentists for the fabrication of cast restoration. Method: A self administered questionnaire was distributed to dentists present at two national dental meeting held at Abuja and Lagos in 2011. The questionnaire assessed their choice of impression materials and technique. Result: Fifty one out of 70 questionnaires were returned filled giving a response rate of 73%. There were 54.9% of the respondents who reported addition curing silicone impression as their first choice material for cast restorations, while 27.4% use alginate as first choice impression. The use of stock plastic trays by the respondents was significantly higher than metal and custom trays. Two-third of the respondents poured their impressions within one hour. All the respondents poured alginate impression after 15 minutes. A significantly high percentage (76%) of the respondents did not retract the free gingival before taking impression. Conclusion: The use of alginate impressions to produce cast restorations was common among the respondents. Since no previous study has documented the use of alginate to produce accurate fitting cast restorations, there is need to investigate the accuracy of alginate impressions in a clinical setting.Keywords: Impression material, impression technique, impression trayNig Dent J Vol 20 No. 1 Jan - June 201

Decomposing the rural–urban gap in factors associated with childhood immunisation in sub-Saharan Africa: evidence from surveys in 23 countries

Background: About 31 million children in sub-Saharan Africa (SSA) suffer from immunisation preventable diseases yearly and more than half a million children die because of lack of access to immunisation. Immunisation coverage has stagnated at 72% in SSA over the past 6 years. Due to evidence that full immunisation of children may be determined by place of residence, this study aimed at investigating the rural–urban differential in full childhood immunisation in SSA. Methods: The data used for this study consisted of 26 241 children pooled from 23 Demographic and Health Surveys conducted between 2010 and 2018 in SSA. We performed a Poisson regression analysis with robust Standard Errors (SEs) to determine the factors associated with full immunisation status for rural and urban children. Likewise, a multivariate decomposition analysis for non-linear response model was used to examine the contribution of the covariates to the observed rural and urban differential in full childhood immunisation. All analyses were performed using Stata software V.15.0 and associations with a p<0.05 were considered statistically significant. Results: More than half of children in urban settings were fully immunised (52.8%) while 59.3% of rural residents were not fully immunised. In all, 76.5% of rural–urban variation in full immunisation was attributable to differences in child and maternal characteristics. Household wealth was an important component contributing to the rural–urban gap. Specifically, richest wealth status substantially accounted for immunisation disparity (35.7%). First and sixth birth orders contributed 7.3% and 14.9%, respectively, towards the disparity while 7.9% of the disparity was attributable to distance to health facility. Conclusion: This study has emphasised the rural–urban disparity in childhood immunisation, with children in the urban settings more likely to complete immunisation. Subregional, national and community-level interventions to obviate this disparity should target children in rural settings, those from poor households and women who have difficulties in accessing healthcare facilities due to distance

Chiral models in dilaton-Maxwell gravity

We study symmetry properties of the Einstein-Maxwell theory nonminimaly coupled to the dilaton field. We consider a static case with pure electric (magnetic) Maxwell field and show that the resulting system becomes a nonlinear sigma-model wich possesses a chiral representation. We construct the corresponding chiral matrix and establish a representation which is related to the pair of Ernst-like potentials. These potentials are used for separation of the symmetry group into the gauge and nongauge (charging) sectors. New variables, which linearize the action of charging symmetries, are also established; a solution generation technique based on the use of charging symmetries is formulated. This technique is used for generation of the elecricaly (magneticaly) charged dilatonic fields from the static General Relativity ones.Comment: 9 pages in LaTex; published in Gen. Rel. Grav. 32 (2000) pp 1389-139

Chromosome segregation in Archaea : SegA– and SegB–DNA complex structures provide insights into segrosome assembly

Genome segregation is a vital process in all organisms. Chromosome partitioning remains obscure in Archaea, the third domain of life. Here, we investigated the SegAB system from Sulfolobus solfataricus. SegA is a ParA Walker-type ATPase and SegB is a site-specific DNA-binding protein. We determined the structures of both proteins and those of SegA–DNA and SegB–DNA complexes. The SegA structure revealed an atypical, novel non-sandwich dimer that binds DNA either in the presence or in the absence of ATP. The SegB structure disclosed a ribbon–helix–helix motif through which the protein binds DNA site specifically. The association of multiple interacting SegB dimers with the DNA results in a higher order chromatin-like structure. The unstructured SegB N-terminus plays an essential catalytic role in stimulating SegA ATPase activity and an architectural regulatory role in segrosome (SegA–SegB–DNA) formation. Electron microscopy results also provide a compact ring-like segrosome structure related to chromosome organization. These findings contribute a novel mechanistic perspective on archaeal chromosome segregation

Prevalence of intestinal parasitic infections among HIV patients in Benin City, Nigeria

This study was carried out to determine the presence of intestinal parasites and their correlation with CD4+ T-cell counts and demographics among human immunodeficiency virus (HIV)-positive patients in Benin City, Nigeria. Stool specimens from 2,000 HIV-positive patients and 500 controls (HIV-negative individuals) were examined for ova, cysts, or parasites, using standard procedures. In addition, patient's blood samples were analyzed for CD4 counts by flow cytometry. An overall prevalence rate of 15.3% was observed among HIV-positive patients while 6.2% was noted among non-HIV subjects. HIV status was a significant (P<0.0001) risk factor for acquiring intestinal parasitic infections. Male gender, CD4 count <200cell/µl, and diarrhea were significantly associated with an increased prevalence of intestinal parasitic infections among HIV-positive patients. The level of education, occupation, and source of water among HIV patients significantly (P<0.0001) affected the prevalence of intestinal parasitic infections. Ascaris lumbricoides was the most predominant parasite in both HIV-positive patients and controls. A CD4 count <200 cells/µl was significantly associated with only Isospora belli and Cryptosporidium infections. The presence of pathogenic intestinal parasites such as A. lumbricoides, hookworm, Giardia intestinalis, Entamoeba histolytica, Trichuris trichiura, and Taenia species among HIV-infected persons should not be neglected. Cryptosporidium species and I. belli were the opportunistic parasites observed in this study. Routine screening for intestinal parasites in HIV-positive patients is advocated

Microarray Analysis of the Effect of Streptococcus equi subsp. zooepidemicus M-Like Protein in Infecting Porcine Pulmonary Alveolar Macrophage

Streptococcus equi subsp. zooepidemicus (S. zooepidemicus), which belongs to Lancefield group C streptococci, is an important pathogen of domesticated species, causing septicemia, meningitis and mammitis. M-like protein (SzP) is an important virulence factor of S. zooepidemicus and contributes to bacterial infection and antiphagocytosis. To increase our knowledge of the mechanism of SzP in infection, we profiled the response of porcine pulmonary alveolar macrophage (PAM) to infection with S. zooepidemicus ATCC35246 wild strain (WD) and SzP-knockout strain (KO) using the Roche NimbleGen Porcine Genome Expression Array. We found SzP contributed to differential expression of 446 genes, with upregulation of 134 genes and downregulation of 312 genes. Gene Ontology category and KEGG pathway were analyzed for relationships among differentially expressed genes. These genes were represented in a variety of functional categories, including genes involved in immune response, regulation of chemokine production, signal transduction and regulation of apoptosis. The reliability of the data obtained from the microarray was verified by performing quantitative real-time PCR on 12 representative genes. The data will contribute to understanding of SzP mediated mechanisms of S. zooepidemicus pathogenesis

Characterization and simulation of cDNA microarray spots using a novel mathematical model

<p>Abstract</p> <p>Background</p> <p>The quality of cDNA microarray data is crucial for expanding its application to other research areas, such as the study of gene regulatory networks. Despite the fact that a number of algorithms have been suggested to increase the accuracy of microarray gene expression data, it is necessary to obtain reliable microarray images by improving wet-lab experiments. As the first step of a cDNA microarray experiment, spotting cDNA probes is critical to determining the quality of spot images.</p> <p>Results</p> <p>We developed a governing equation of cDNA deposition during evaporation of a drop in the microarray spotting process. The governing equation included four parameters: the surface site density on the support, the extrapolated equilibrium constant for the binding of cDNA molecules with surface sites on glass slides, the macromolecular interaction factor, and the volume constant of a drop of cDNA solution. We simulated cDNA deposition from the single model equation by varying the value of the parameters. The morphology of the resulting cDNA deposit can be classified into three types: a doughnut shape, a peak shape, and a volcano shape. The spot morphology can be changed into a flat shape by varying the experimental conditions while considering the parameters of the governing equation of cDNA deposition. The four parameters were estimated by fitting the governing equation to the real microarray images. With the results of the simulation and the parameter estimation, the phenomenon of the formation of cDNA deposits in each type was investigated.</p> <p>Conclusion</p> <p>This study explains how various spot shapes can exist and suggests which parameters are to be adjusted for obtaining a good spot. This system is able to explore the cDNA microarray spotting process in a predictable, manageable and descriptive manner. We hope it can provide a way to predict the incidents that can occur during a real cDNA microarray experiment, and produce useful data for several research applications involving cDNA microarrays.</p