Experimental Investigation of the Impact of Cathode Grade on Sludge Formation at the Cathode Block-Aluminum Interface of Hall–Héroult Cells

Metallurgical and Materials Transactions B - The presence of resistive sludge on the cathode surface in Hall–Héroult cells can increase the aluminum production costs and reduces cell...     

Influence of density, elasticity, and structure on ultrasound transmission through trabecular bone cylinders

The aim of this in vitro study is to evaluate the potentiality of quantitative ultrasound (QUS) to separate information on density, elasticity, and structure on specimens of trabecular bone. Fifteen cylinders of spongy bone extracted from equine vertebrae were progressively demineralized and subjected to QUS, micro computed tomography (muCT), Dual energy X-ray absorptiometry (DXA) at various mineralization levels. Eventually all cylinders underwent a compression test to calculate the Young's modulus. Correlation analysis shows that speed of sound (SOS) is strictly associated to bone mineral density (BMD), Young's modulus, and all muCT parameters except for degree of anisotropy (DA). Fast wave amplitude (FWA) is directly correlated with bone surface and total volume ratio (BS/TV) and trabecular separation (Tb Sp), and inversely correlated with trabecular number (Tb N). Because muCT parameters were strictly correlated to BMD and Young's modulus data, partial correlation analysis was performed between SOS, FWA, and structural and elastic data in order to eliminate the effect of density. SOS was significantly correlated to bone volume and total volume ratio (BV/TV), BS/TV, and Young's modulus, and FWA was significantly correlated to Tb Sp only. These results show that SOS is strongly influenced by volumetric mineral bone density and elastic modulus of the specimen, and FWA is mainly affected by trabecular separation independently on density. Therefore, SOS and FWA are able to provide different and complementary information, at least on trabecular bone samples.     

Coating of ZrO2 supports with a biological glass

The possibility of obtaining a good bioactive coating on biomedical devices made with zirconia ceramic was considered. Yttria partially stabilized zirconia was used to produce suitable substrates. The obtained adhesion was good (66±13 MPa) and encouraging for biomedical applications. Small microcrystals formed inside and on the surface of the glass layer. These microcrystals transformed the glass into a glass-ceramic. An accurate investigation of the nature of this microcrystal formation was carried out to verify its compatibility with the planned biomedical applications. © 1998 Chapman & Hall     

Gentic risk for schizophrenia, birthweight, and cerebral ventricular enlargement.

Recent work by Silverton, Finello, Mednick, and F. Schulsinger (1985) indicates a relation between low birthweight and cerebral ventricular enlargement, as assessed in adulthood, in a group of subjects at risk for schizophrenia. In the present study, we examined the role of low birthweight in ventricular enlargement and tested the hypothesis that low birth weight interacts with a genetic predisposition for schizophrenia in its association with enlarged ventricles. This study reports on 34 subjects of the Danish high-risk-for-schizophrenia prospective study. Birthweight, paternal schizophrenia spectrum disorder (PSSD), and an interaction term for these two variables were analyzed in a regression with ventricle-to-brain ratio (VBR) as the dependent variable. As in Silverton et al. (1985), birthweight significantly contributed to the variance in VBR. Although PSSD did not significantly contribute to the variance in VBR, there was a significant interaction effect of birthweight and PSSD on VBR. Results were discussed in terms of a diathesis-stress model of schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Expression and enzymic activity of ecto 5''-nucleotidase in the human male genital tract

The factor structure of the Millon Clinical Multiaxial Inventory (Millon, 1994; MCMI-III) was assessed among 444 African American inpatient substance abusers and constitutes the first factor analysis of the MCMI-III. We found 3 main factors: General Maladjustment, Paranoid Behavior/Thinking With Detached Emotionality, and Antisocial Acting Out. These factors were essentially similar to previous findings of factor studies with the MCMI and MCMI-II across diverse populations. This factor invariance should lend credibility to the revised test and spur additional research into its psychometric properties.     

Long-term in vivo experimental investigations on magnesium doped hydroxyapatite bone substitutes

Despite several efforts to find suitable alternatives to autologous bone, no bone substitute currently available provides the same characteristics and properties. Nevertheless, among the wide range of materials proposed as bone substitutes, calcium phosphate materials represent the most promising category and the present study is aimed at improving the knowledge on non-stoichiometric magnesium-doped hydroxyapatite substitutes (Mg-HA), tested in two different formulations: Mg-HA Putty and Mg-HA Granules. These bone substitutes were implanted bilaterally into iliac crest bone defects in healthy sheep and comparative histological, histomorphometric, microhardness and ultrastructural assessments were performed 9, 12, 18 and 24 months after surgery to elucidate bone tissue apposition, mineralization and material degradation in vivo. The results confirmed that the biomimetic bone substitutes provide a histocompatible and osteoconductive structural support, during the bone formation process, and give essential information about the in vivo resorption process and biological behavior of biomimetic bone substitutes.     

Growth on poly(l-lactic acid) porous scaffold preserves CD73 and CD90 immunophenotype markers of rat bone marrow mesenchymal stromal cells

Few data are available on the effect of biomaterials on surface antigens of mammalian bone marrow-derived, adult mesenchymal stromal cells (MSCs). Since poly(l-lactic acid) or PLLA is largely used in tissue engineering of human bones, and we are developing a reverse engineering program to prototype with biomaterials the vascular architecture of bones for their bioartificial reconstruction, both in humans and animal models, we have studied the effect of porous, flat and smooth PLLA scaffolds on the immunophenotype of in vitro grown, rat MSCs in the absence of any coating, co-polymeric enrichment, and differentiation stimuli. Similar to controls on plastic, we show that our PLLA scaffold does not modify the distribution of some surface markers in rat MSCs. In particular, the maintained expression of CD73 and CD90 on two different subpopulations (small and large cells) is consistent with their adhesion to the PLLA scaffold through specialized appendages, and to their prominent content in actin. In addition, our PLLA scaffold favours retention of the intermediate filament desmin, believed a putative marker of undifferentiated state. Finally, it preserves all rat MSCs morphotypes, and allows for their survival, adhesion to the substrate, and replication. Remarkably, a subpopulation of rat MSCs grown on our PLLA scaffold exhibited formation of membrane protrusions of uncertain significance, although in a size range and morphology compatible with either motility blebs or shedding vesicles. In summary, our PLLA scaffold has no detrimental effect on a number of features of rat MSCs, primarily the expression of CD73 and CD90.     

Development of a Mild Procedure for the Addition of Bisulfite to Electrophilic Olefins

The sulfonylation of activated alkenes is an important yet unexplored reaction due to the harshness of conditions required. We have identified a procedure which allowed the reaction of alkenes with equimolar amounts of bisulfite at room temperature.