Simulation of residual stresses at holes in tempered glass: a parametric study

This work presents a full 3D numerical study of the residual stresses in tempered (toughened) glass near holes using Narayanaswamy’s model for the tempering process. It is the objective of the paper to elucidate the influence on the minimal residual compressive stresses at holes from variations in: the far-field stress, plate thickness, hole diameter and the interaction between holes and edges and corners. The work presents novel results for the sensitivity of the residual stresses to geometric features and provides a design tool for estimating residual stresses at holes for different geometries. An example of how to extrapolate the results in terms of far-field stresses is given.     

Theoretical analysis of tuning properties for a phase-tunable DFBlaser

The device consists of a conventional or a λ/4-shifted DFB (distributed-feedback) laser monolithically integrated with an external waveguide section with separate electrodes for phase control. Tuning curves are presented for threshold current, frequency, linewidth, and output power. The analysis demonstrates a generally higher side mode suppression and larger frequency tuning range but also a larger linewidth for the λ/4-shifted device compared to the device with a conventional DFB section     

Stability and dynamic properties of multi-electrode laser diodesusing a Green's function approach

In DFB (distributed feedback) lasers, the shape of the longitudinal intensity and carrier density distributions changes above threshold as a result of spatial hole burning. The longitudinally distributed coupling of spontaneous emission into the lasing mode also plays an important role for the noise properties. The authors demonstrate how both effects can be included in a dynamic analysis. They extend their previously developed theory for multielectrode lasers to enable calculation of stability properties as well as small-signal modulation responses and noise spectra. The theory is used to study global and local stability of the stationary solutions (modes). The numerical results for several laser structures are presented. It is shown that symmetric DFB lasers are likely to exhibit pitchfork bifurcations in their static tuning characteristics as the current is increased. The authors discuss how the presence or proximity of such instabilities can affect the modulation and noise properties, and in particular, the spectral linewidth     

Digitalis-like and vasoconstrictor effects of endogenous digoxin-like factor(s) from the venom of Bufo marinus toad

Digitalis glycoside-like properties of the Bufo marinus toad crude venom and one of its constituents, bufalin, were studied in various assay systems. In concentrations 0.3-30 micrograms/ml crude venom increased the contractility of isolated electrically driven rat atria, constricted rat aortic rings, inhibited ouabain-sensitive Na+,K(+)-ATPase in rat erythrocytes and the Na+,K(+)-pump in rat aorta, and cross-reacted with antidigoxin antibody from the dissociation enhanced lanthanide fluoroimmunoassay (DELFIA). These effects were unaffected by adrenoceptor blockers and the 5-HT antagonist, deseril, but were blocked by antidigoxin antibody. Bufalin (10-30 microM) increased myocardial contractility and inhibited Na+,K(+)-ATPase in rat erythrocytes similarly to crude Bufo marinus venom. In rat aorta bufalin showed weak and delayed vasoconstrictor activity which was antagonized by 2 microM phentolamine, and had a biphasic effect on the Na+,K(+)-pump; 0.5-1.0 microM bufalin stimulated the pump, while higher concentrations inhibited its activity. Although the effects of bufalin were blocked by antidigoxin antibody, bufalin showed very low digoxin-like immunoreactivity in the DELFIA. These observations suggest that, in addition to bufalin, Bufo marinus venom contains at least one more digitalis-like steroid with significant intrinsic vasoconstrictor activity which, unlike bufalin, constricts the blood vessels acting directly via inhibition of the sodium pump in the vascular smooth muscle membrane.     

Human gamma-interferon expression in the mammary gland of transgenic mice

Transgenic mice carrying a hybrid gene consisting of ovine beta-lactoglobulin gene sequences and human gamma-interferon (hIFN-g) cDNA were produced. hIFN-g expression in the mammary gland of two lactating transgenic founder females was found. The concentration of active hIFN-g in the milk was estimated as being ca. 1800 IU/ml. The hIFN-g ability to express in the mammary gland was found in the progeny of transgenic founder male.