In-situ observations of phase transformations in titanium

An in-situ laser-scanning confocal microscopy study has been undertaken on the phase transformations in highpurity titanium. Observations of the β-Ti to α-Ti were observed to proceed with a pronounced Widmanstätten plate morphology due to the large β-Ti grain size. An anomalous transformation was also observed, with the α-Ti growing with a defined ledge-like surface relief. The observed transformation morphologies are discussed with reference to the crystallography of the regions, analyzed using electron-backscatter diffraction.     

…On the direct programming of CNC milling equipment

This paper discusses the use of expert software which directly programs Computer Numerical Control (CNC) milling equipment from engineering style Computer-Aided-Design (CAD) drawings. Currently available software provides only semi-automatic programming based upon strict drawing format, user selected tools and user supplied tool path information. (DPS) derives part feature, tool selection, and tool path from “loosely” specified CAD drawings without direct user control. Other CNC programming methods are error prone and are slow to produce accurate CNC programs. The new technology eliminates programming error and completes processing in seconds rather than hours or days, thus providing for a true Computer Integrated Manufacturing (CIM) environment. DPS is in use on various 2D and 3D milling environments as well as on several types of small or personal computers and CAD systems. Additional systems and environments can be supported. DPS is designed to operate efficiently with AutoDesk, Inc.'s AutoCAD and Hewlett Packard 9000/320 ME-10 (HP-UX) based drawings. An additional implementation is running on SCO XENIX/386.

This paper presents technology and productivity improvements for various classes of DPS systems available today. Examples of actual use, productivity improvements and product dependencies are discussed and illustrated.     

Clinical features and prognostic implications of familial hypertrophic cardiomyopathy related to the cardiac myosin-binding protein C gene

BACKGROUND: Little information is available on phenotype-genotype correlations in familial hypertrophic cardiomyopathy that are related to the cardiac myosin binding protein C (MYBPC3) gene. The aim of this study was to perform this type of analysis. METHODS AND RESULTS: We studied 76 genetically affected subjects from nine families with seven recently identified mutations (SASint20, SDSint7, SDSint23, branch point int23, Glu542Gln, a deletion in exon 25, and a duplication/deletion in exon 33) in the MYBPC3 gene. Detailed clinical, ECG, and echocardiographic parameters were analyzed. An intergene analysis was performed by comparing the MYBPC3 group to seven mutations in the beta-myosin heavy-chain gene (beta-MHC) group (n=52). There was no significant phenotypic difference among the different mutations in the MYBPC3 gene. However, in the MYBPC3 group compared with the beta-MHC group, (1) prognosis was significantly better (P<0.0001), and no deaths occurred before the age of 40 years; (2) the age at onset of symptoms was delayed (41+/-19 versus 35+/-17 years, P<0.002); and (3) before 30 years of age, the phenotype was particularly mild because penetrance was low (41% versus 62%), maximal wall thicknesses lower (12+/-4 versus 16+/-7 mm, P<0.03), and abnormal T waves less frequent (9% versus 45%, P<0.02). CONCLUSIONS: These results are consistent with specific clinical features related to the MYBPC3 gene: onset of the disease appears delayed and the prognosis is better than that associated with the beta-MHC gene. These findings could be particularly important for the purpose of clinical management and genetic counseling in familial hypertrophic cardiomyopathy.     

The mental health arena.

If C. A. Kiesler's (1977) comparative analysis of the training of psychologists vs psychiatrists proves to be true after closer inspection, this analysis can document that doctoral-level psychologists have as much (or more) training as psychiatrists yet receive considerably less income. The reasons that psychiatrists dominate mental health settings are reviewed, and it is argued that the mythical nature of the public's collective approaches to physicians should be exposed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mutations in either nucleotide-binding site of P-glycoprotein (Mdr3) prevent vanadate trapping of nucleotide at both sites

Vanadate trapping of nucleotide and site-directed mutagenesis were used to investigate the role of the two nucleotide-binding (NB) sites in the regulation of ATP hydrolysis by P-glycoprotein (mouse Mdr3). Mdr3, tagged with a hexahistidine tail, was overexpressed in the yeast Pichia pastoris and purified to about 90% homogeneity by Ni-affinity chromatography. This protocol yielded purified, reconstituted Mdr3 which exhibited high verapamil stimulation of ATPase activity with a Vmax of 4.2 micromol min-1 mg-1 and a KM of 0.7 mM, suggesting that Mdr3 purified from P. pastoris is highly functional. Point mutations were introduced into the core consensus sequence of the Walker A or B motifs in each of the two NB sites. The mutants K429R, K1072R (Walker A) and D551N, D1196N (Walker B) were functionally impaired and unable to confer cellular resistance to the fungicide FK506 in the yeast Saccharomyces cerevisiae. Single and double mutants (K429R/K1072R, D551N/D1196N) were expressed in P. pastoris, and the effect of these mutations on the ATPase activity of Mdr3 was characterized. Purified reconstituted Mdr3 mutants showed no detectable ATPase activity compared to proteoliposomes purified from negative controls (<5% of wild-type Mdr3). Vanadate readily induced trapping of 8-azido-nucleotide in the wild-type enzyme after a short 10 s incubation, and specific photolabeling of Mdr3 after UV irradiation. No such vanadate-induced trapping/photolabeling was observed in any of the mutants, even after a 60 min trapping period at 37 degrees C. Since vanadate trapping with 8-azido-ATP requires hydrolysis of the nucleotide, the data suggest that 8-azido-ATP hydrolysis is dramatically impaired in all of the mutant proteins (<0.3% activity). These results show that mutations in either NB site prevent single turnover and vanadate trapping of nucleotide in the nonmutant site. These results further suggest that the two NB sites cannot function independently as catalytic sites in the intact molecule. In addition, the N- or C-terminal NB sites appear functionally indistinguishable, and cooperative interactions absolutely required for ATP hydrolysis may originate from both sites.     

Properties of an elementary class of fluids with nondissipative viscous stresses

A class of fluids with both dissipative and nondissipative viscous stresses is analyzed. The class is delineated by the three assumptions, (1) the stress is isotropic, (2) the fluid admits no natural time scale, (3) the Stoke's assumption, tr(t) = − 3p, is satisfied. The constitutive relations are shown to be uniquely determined in terms of the linear bulk viscosity and the linear shear viscosity. The characteristic features of such fluids are obtained and experimental distinguishability between these fluids and the classic Navier-Stokes fluid is examined in detail. In general, it is surprisingly difficult to distinguish between the fluids considered here and the classic Navier-Stokes fluids, even though there are characteristic anomalies associated with the nondissipative stresses.     

Effect of different solutions of preservatives on the endothelial function of coronary arteries in rats

The effects of cold storage and type of preservation solution on coronary endothelial function are not well established. Experiments were designed to evaluate coronary endothelial-dependent relaxation after a 4-hour cold (4 degrees C) storage in different preservation solutions. Rat hearts, mounted in the Langendorff apparatus, were arrested with a 10-minute perfusion of 4 degrees C crystalloid hyperkaliemic cardioplegic solution (CHCS) (KCl 24 mEq/l) and stored for 4 hours in the following preservation solutions: CHCS (n = 6), Krebs-Ringer solution (KR) (n = 6), 0.9% NaCl (NS) (n = 6) and the University of Wisconsin solution (UW) (n = 6). A fifth group (n = 6) was perfused and stored in UW solution. Endothelium-dependent and independent coronary artery vasorelaxations were respectively tested by infusing 5-hydroxytryptamine (5-HT) (10(-6) mol/l) and sodium nitroprusside (SNP) (10(-5) mol/l) before and after the storage period. In hearts stored with CHCS or KR, coronary artery flow increase to 5-HT and SNP infusions were not significantly affected. However, in hearts preserved with NS or UW solutions, 5-HT coronary response was significantly decreased, indicating endothelial dysfunction. In addition to these findings, coronary flow increase to SNP infusion was decreased in the group perfused and stored with UW, suggesting smooth muscle dysfunction. These experiments suggest that 4-hour cold storage in NS or UW impairs endothelial-dependent coronary relaxation in the isolated rat heart model.     

On the functional forms of activity coefficients and their properties

A complete system of partial differential equations is obtained for the logarithms of activity coefficients of real chemical mixtures. All solutions of these equations are obtained under mild regularity conditions and the conditions that the limit of ln (f_α), as n_α/n tends to unity, is equal to zero. It is shown that all of the functions ln (f_α) can be determined if any one of them is a known function of temperature, pressure and the independent mole fractions. These results are used to compute the deviations of partial and total volume, entropy and specific heats at constant pressure, and the laws of mass action from what would be given for ideal mixtures. Conditions for static and dynamic stability of equilibrium are obtained, and a forward time integration procedure is given for satisfaction of the laws of mass balance and the full form of the laws of mass action.     

On a closure of the governing equations of defect dynamics and the resulting theory of the plastic state

The equations of defect dynamics are derived from the single system of relations that specifies the time rate of change of the dislocation densities. The resulting source equations are shown to admit a 12-fold gauge group and the resulting kinematic equations are shown to admit a 15-fold gauge group. The generators of the two gauge groups are determined by the requirements that the Burgers and Frank vectors have their classical representations. This determination results in a unique decomposition of all quantities in terms of sums of internal variables and external geometric variables, and represents the first and second closures of the field equations. The presence of a unique external system of geometric variables permits derivation of the forms of the equations of balance of mass, momentum, moment of momentum and energy. The third closure is obtained through use of the practices of nonequilibrium thermodynamics. This results in a system of equations that determines the dislocation currents in terms of the distortion, the dislocation density and the geometric strain measures. A class of models is exhibited wherein most of the properties of plasticity theories are obtained.     

Programs for computer implementation of the exterior calculus with applications to isovector calculations

Program listings are given in the REDUCE 2 Algebraic Programming system that implement the following operations of the exterior calculus: exterior multiplication, exterior differentiation, inner multiplication, Lie differentiation, and Lie multiplication. These programs realize exterior forms and vector fields by resolving them on unevaluated systems of operators with the necessary algebraic properties. Use of these programs in the computation of isovectors of ideals of exterior forms is illustrated for the case where the ideal is generated by the system of exterior forms of degree two that characterize the equations for shallow water waves.