Comparing Five and Lower-Dimensional Grain Boundary Character and Energy Distributions in Copper: Experiment and Molecular Statics Simulation

Metallurgical and Materials Transactions A - The misorientation of 515 grain boundaries has been determined using electron backscatter diffraction data from an 18 μm thick copper foil with...     

Managing complex orthodontic problems: the use of implants for anchorage

In congestive heart failure captopril modifies the left ventricular filling pattern mainly by unloading the heart. We investigated whether the structural characteristics of the left ventricle may influence the acute effects of captopril on this pattern in patients with untreated hypertensive (H group, 6 patients) or idiopathic (I group, 14 patients) cardiomyopathy. We evaluated changes of pulsed Doppler mitral flow, of systemic arterial and wedge pulmonary pressures 40 min after 25 mg captopril administered sublingually, and correlated these changes with the M-mode echocardiographic relative wall thickness index (h/r). Baseline mean arterial pressure (H = 137 +/- 20 mm Hg, mean +/- SD, I = 95 +/- 19 mm Hg; p < 0.001), and h/r (H = 0.38 +/- 0.03, I = 0.28 +/- 0.09; p < 0.05) were greater in the high blood pressure group; wedge pressure, echocardiographic biplane ejection fraction, and Doppler indexes of the left ventricular filling were similar in the two populations. After captopril, ejection fraction did not change significantly, mean arterial pressure decreased significantly in hypertensive patients (H group, baseline = 137 +/- 20, captopril = 119 +/- 10, p = 0.02; I group, baseline = 95 +/- 19, captopril = 90 +/- 24, p = nonsignificant), and the wedge pressure was reduced by the same extent in both groups (H group, baseline = 27.7 +/- 3, captopril = 21 +/- 7, p < 0.05; I group, baseline = 20 +/- 12, captopril = 15 +/- 8, p < 0.05). In the H group early mitral flow increased [(E wave integral) x (mitral annulus area)] by 38 +/- 15%, and was almost steady in the I group (-1.3 +/- 30%; group H vs. I = p < 0.01); late mitral flow [(A wave integral) x (mitral annulus area)] showed a pattern exactly opposite to this (H = +0.4 +/- 40%, I = +38 +/- 19; p < 0.01). In the whole population there was a significant correlation between the early/late flow ratio variations and baseline h/r (r = 0.6, p < 0.05). In chronic congestive heart failure, changes in left ventricular filling with captopril are related to h/r: a higher index, as recorded in the H group, is associated with "true normalization' of the filling pattern after captopril; a lower index, as recorded in the I group, is associated with "pseudonormalization' despite a similar decrease of left ventricular filling pressure.     

Preparation of sols from water-alcohol solutions of tetraethyl orthosilicate and SnCl<Subscript>4</Subscript> and the effect of sol composition on the surface morphology of sol-gel films

We describe a process for the preparation of sols from water-alcohol solutions of tetraethyl orthosilicate and SnCl₄. The kinetics of this process have been studied by measuring the electrical conductivity of the sols, and the optical absorption spectra of the sols have been measured. The surface morphology of films prepared from the sols has been examined by scanning electron microscopy. The results are used to assess the influence of preparation conditions, sol composition, and processes underlying sol formation on the surface morphology of the gas-sensing films prepared from the sols.     

The concept of synergism in radiobiology]

We have demonstrated previously that pemphigus vulgaris (PV)-IgG induces activation of phospholipase C (PLC), production of inositol 1,4,5-trisphosphate, and a rapid transient increase in [Ca2+]i in cultured human keratinocytes, leading to secretion of plasminogen activator and cell-cell detachment in cell culture. In the current study, to examine the involvement of protein kinase C (PKC) in the mechanism of blister formation in PV, we studied the PV-IgG-induced translocation of PKC isozymes from the cytosol to the particulate/cytoskeleton (p/c) fractions and the activation of PKC in human keratinocytes. Cells cultured in Eagle's minimum essential medium were incubated with PV-IgGs for 30 s, 1 min, 5 min, or 30 min. PV-IgG binding to the cell surface antigen (desmoglein III) induced translocation of PKC-alpha from the cytosol to the p/c fractions within 30 s, with a peak at 1 min that lasted at least 30 min. PKC-delta also was translocated within 1 min and reached a peak at 5 min but was reduced to basal levels at 30 min. Alternatively, PKC-eta translocation to the p/c fraction was induced slowly, taking more than 5 min, and was reduced to approximately half-maximum at 30 min, whereas PKC-zeta translocation reached a maximum at 30 s, rapidly returning to baseline by 5 min after PV-IgG stimulation. The total PKC activity in the p/c fraction also was increased after PV-IgG exposure, peaked at 1 min, and was sustained for at least 30 min. These findings suggest that a unique activation profile of PKC isomers may be involved in mediating the intracellular signaling events induced by PV-IgG binding to desmoglein III in cultured human keratinocytes.     

A strain of the yeast Saccharomyces cerevisiae for testing environmental mutagens based on interaction of the mutations rad2 and him1

The interaction between mutations at the RAD2 and HIM1 genes was studied. The RAD2 gene encodes endonuclease involved in nucleotide excision repair. Mutants at this gene are highly sensitive to the lethal effect of a variety of mutagens. The product of the HIM1 gene is needed for correction of mismatched bases and repair of premutational DNA damage. Mutations in this gene lead to the formation of the mutator phenotype and high sensitivity to induced mutagenesis. The double rad2 him1 mutant manifested the synergic type of interaction. The level of UV-induced mutagenesis in the double mutant was five times higher than in single mutants, and the absolute yield of forward mutations in five genes controlling adenine biosynthesis was 1 to 2%. UV-induced mutagenesis was increased, at low doses, by several orders of magnitude in the double mutant, compared to the wild-type strain. The high level of mutagenesis in this mutant was caused by ethyl and methyl methanesulfonate. These properties of the stock with the double rad2 him1 mutation makes it promising as a tester in analysis of the gene toxicity of different substances.