2,079 research outputs found
Molecular basis for resistance of acanthamoeba tubulins to all major classes of antitubulin compounds
Tubulin is essential to eukaryotic cells and is targeted by several antineoplastics, herbicides, and antimicrobials. We demonstrate that Acanthamoeba spp. are resistant to five antimicrotubule compounds, unlike any other eukaryote studied so far. Resistance correlates with critical amino acid differences within the inhibitor binding sites of the tubulin heterodimers
The Anomalous Hall Effect in YBaCuO
The temperature dependence of the normal state Hall effect and
magnetoresistance in YBaCuO is investigated using the Nearly
Antiferromagnetic Fermi Liquid description of planar quasiparticles. We find
that highly anisotropic scattering at different regions of the Fermi surface
gives rise to the measured anomalous temperature dependence of the resistivity
and Hall coefficient while yielding the universal temperature dependence of the
Hall angle observed for both clean and dirty samples. This universality is
shown to arise from the limited momentum transfers available for the anomalous,
spin fluctuation scattering and is preserved for any system with strong
antiferromagnetic correlations.Comment: REVTeX, 10 pages + 4 figures in a single (compressed/uuencoded)
PostScript fil
Taurodontism in the first permanent molars in Van der Woude syndrome compared to isolated cleft palate
Objectives: To analyse prevalence, pattern, and severity of taurodontism in individuals with Van der Woude syndrome (VWS) exhibiting cleft palate and compare with aged-matched non-syndromic cleft palate (NSCP) and non-cleft controls. Materials and methods: One hundred and seventy-eight dental panoramic tomographs (DPTs) (105 girls and 73 boys) consisting of 42 VWS patients (x = 8.55 +/- 1.02 years), 42 NSCP patients (x = 8.59 +/- 1.02 years), and 94 normative non-cleft children (x = 8.79 +/- 1.16 years) were assessed and their first permanent molars evaluated. Measurement 3 of the taurodontism index developed by Shifman and Chanannel with the Tulensalo modification was used. Prevalence, pattern, and severity were compared between groups. Statistical differences were determined by one-way analysis of variance and Fisher test. Repeatability was calculated by Cohens Kappa test. Results: The prevalence of taurodontic molars was 59.5% in VWS, 45.2% in NSCP, and 26.6% in non-cleft controls.The prevalence and severity of taurodontism in VWS and NSCP were significantly higher than in non-cleft children in all first permanent molars. There was no significant difference in prevalence and severity between VWS and NSCP. The odds for having taurodontism in the VWS group was approximately double compared to the NSCP group. Most of the taurodontic molars showed hypotaurodontism and taurodontism occurred bilaterally more frequently than unilaterally. Conclusion: This study shows a higher prevalence of taurodontism in VWS and NSCP. Most taurodontic molars are hypotaurodontic and most occur bilaterally.Peer reviewe
Behavior of an Escolar Lepidocybium flavobrunneum in the Windward Passage as Determined by Popup Satellite Archival Tagging
In June 2003, fisheries research was conducted in the Windward Passage using a chartered commercial pelagic longline vessel (Rice and Snodgrass 2003). This paper describes the habitat use by an escolar in this location tagged with a pop-up satellite archival tag (PSAT) that remained attached to the fish for 14 d. Data recovered from the PSAT were used to directly document diel vertical migration and ambient temperature range for the first time in a mesopelagic teleost
Noggin null allele mice exhibit a microform of holoprosencephaly
Holoprosencephaly (HPE) is a heterogeneous craniofacial and neural developmental anomaly characterized in its most severe form by the failure of the forebrain to divide. In humans, HPE is associated with disruption of Sonic hedgehog and Nodal signaling pathways, but the role of other signaling pathways has not yet been determined. In this study, we analyzed mice which, due to the lack of the Bmp antagonist Noggin, exhibit elevated Bmp signaling. Noggin−/− mice exhibited a solitary median maxillary incisor that developed from a single dental placode, early midfacial narrowing as well as abnormalities in the developing hyoid bone, pituitary gland and vomeronasal organ. In Noggin−/− mice, the expression domains of Shh, as well as the Shh target genes Ptch1 and Gli1, were reduced in the frontonasal region at key stages of early facial development. Using E10.5 facial cultures, we show that excessive BMP4 results in reduced Fgf8 and Ptch1 expression. These data suggest that increased Bmp signaling in Noggin−/− mice results in downregulation of the hedgehog pathway at a critical stage when the midline craniofacial structures are developing, which leads to a phenotype consistent with a microform of HP
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Autothermal Reforming of Natural Gas to Synthesis Gas
This Project Final Report serves to document the project structure and technical results achieved during the 3-year project titled Advanced Autothermal Reformer for US Dept of Energy Office of Industrial Technology. The project was initiated in December 2001 and was completed March 2005. It was a joint effort between Sandia National Laboratories (Livermore, CA), Kellogg Brown & Root LLC (KBR) (Houston, TX) and Süd-Chemie (Louisville, KY). The purpose of the project was to develop an experimental capability that could be used to examine the propensity for soot production in an Autothermal Reformer (ATR) during the production of hydrogen-carbon monoxide synthesis gas intended for Gas-to-Liquids (GTL) applications including ammonia, methanol, and higher hydrocarbons. The project consisted of an initial phase that was focused on developing a laboratory-scale ATR capable of reproducing conditions very similar to a plant scale unit. Due to budget constraints this effort was stopped at the advanced design stages, yielding a careful and detailed design for such a system including ATR vessel design, design of ancillary feed and let down units as well as a PI&D for laboratory installation. The experimental effort was then focused on a series of measurements to evaluate rich, high-pressure burner behavior at pressures as high as 500 psi. The soot formation measurements were based on laser attenuation at a view port downstream of the burner. The results of these experiments and accompanying calculations show that soot formation is primarily dependent on oxidation stoichiometry. However, steam to carbon ratio was found to impact soot production as well as burner stability. The data also showed that raising the operating pressure while holding mass flow rates constant results in considerable soot formation at desirable feed ratios. Elementary reaction modeling designed to illuminate the role of CO2 in the burner feed showed that the conditions in the burner allow for the direct participation of CO2 in the oxidation chemistry
An attempt to predict success in a vocational rehabilitation program
The purposes of the present study were: to replicate earlier research that had suggested four factors which were related to success in a VR program; to test the ability of a multiple regression equation formed from these four factors to predict success in an independent VR sample; and to evaluate the Phillips Scale of Premorbid Adjustment as a predictor of success in the program. Data for the 40 subjects that had been used by the earlier study were employed in forming a multiple regression equation. Additional data pertaining to the four measures were gathered on an independent sample of 44 subjects. In Group I a significant positive relationship (R = .56, p <.05) between the four variables and success was indicated; however, when the data from subjects in Group II were fitted into the equation, the predictions were far less accurate. Inter-correlations of the variables were computed for both groups. These correlations indicated no significant relationships between any of the four factors and success for Group II. Therefore, this study did not find support for the findings of the previous research
Dental Epithelial Stem Cells Express the Developmental Regulator Meis1
MEIS1 is a key developmental regulator of several organs and participates in stem cell maintenance in different niches. However, despite the murine continuously growing incisor being a well described model for the study of adult stem cells, Meis1 has not been investigated in a dental context. Here, we uncover that Meis1 expression in the tooth is confined to the epithelial compartment. Its expression arises during morphogenesis and becomes restricted to the mouse incisor epithelial stem cell niche, the labial cervical loop. Meis1 is specifically expressed by Sox2(+) stem cells, which give rise to all dental epithelial cell lineages. Also, we have found that Meis1 in the incisor is coexpressed with potential binding partner Pbx1 during both embryonic and adult stages. Interestingly, Meis2 is present in different areas of the forming tooth and it is not expressed by dental epithelial stem cells, suggesting different roles for these two largely homologous genes. Additionally, we have established the expression patterns of Meis1 and Meis2 during tongue, hair, salivary gland and palate formation. Finally, analysis of Meis1-null allele mice indicated that, similarly, to SOX2, MEIS1 is not essential for tooth initiation, but might have a role during adult incisor renewal.Peer reviewe
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