Spectral characterization of a tunable alexandrite laser by rubidium absorption at 780 nm

Rubidium vapor was used to characterize the output of a tunable, pulsed alexandrite laser operating at 780 nm. Rubidium spectra were obtained at temperatures of 23, 50, 110, and 140°C. Excellent agreement was obtained with computer-synthesized spectra which yielded values for the effective laser bandwidth at different operating conditions. The model assumed a Voigt profile for the rubidium5^{2}P_{3/2} leftarrow 5^{2}S_{1/2}transition and a Gaussian profile for the laser pulse. The model also showed that the laser output was spectrally compact with no evidence of energy outside the narrow 780 nm central feature.     

Effect of Enameling on the Strength and Dynamic Fatigue of Soda–Lime–Silica Float Glass

The effect of a glass enamel coating on the strength and fatigue behavior of float glass was investigated. Commercially available enamel that was comprised of Cu₂Cr₂O₄ pigment particles in a bismuth-zinc borosilicate glass matrix was applied to a soda–lime–silica float glass via screen printing, followed by fusion at elevated temperature. Strengths of the enameled specimens were evaluated in biaxial flexure using a ring-on-ring (ROR) test geometry, and the data were analyzed using a conventional two-parameter Weibull distribution. Enameling was found to significantly degrade the strength of the float glass. There was no statistical difference in the characteristic strengths of samples enameled on the air side (66 MPa) compared with samples enameled on the tin side (61 MPa) of the float glass. Fractographic analysis revealed that the failures in the enameled float glass samples initiated at pores and pigment aggregates in the enamel, whereas failures in float glass samples initiated solely from surface flaws. Dynamic fatigue tests were performed on enameled float glass and indented float glass samples to determine the effect of the enamel on the stress corrosion behavior of the enameled components. There was no statistically significant difference between the stress corrosion exponents for the float glass and enameled float glass specimens.     

Identification of new sesquiterpenoids in cephalic secretion of cuckoo bee,Nomada lathburiana (Apoidea,Anthophoridae)

A series of new sesquiterpene ketones and norsesquiterpene ketones could be identified from the cephalic secretion of females of the cuckoo bee,Nomada lathburiana (K.). The major component proved to be 2,6,10-trimethylundeca-(5E)-2,5,9-trien-4-one. Large amounts of high-boiling-point straight-chain hydrocarbons serve as solvents for the volatile, unstable ketones.     

Improved Approximations for Guarding 1.5-Dimensional Terrains

We present a 4-approximation algorithm for the problem of placing the fewest guards on a 1.5D terrain so that every point of the terrain is seen by at least one guard. This improves on the previous best approximation factor of 5 (see King in Proceedings of the 13th Latin American Symposium on Theoretical Informatics, pp. 629–640, 2006). Unlike most of the previous techniques, our method is based on rounding the linear programming relaxation of the corresponding covering problem. Besides the simplicity of the analysis, which mainly relies on decomposing the constraint matrix of the LP into totally balanced matrices, our algorithm, unlike previous work, generalizes to the weighted and partial versions of the basic problem.     

On convection in aluminum reduction cells

The convection pattern in the bath electrolyte and the cathode metal of 150 kamp prebaked anode aluminum reduction cells has been studied by means of radioactive tracers. The initial distribution of the tracers—²⁴Na for the bath and¹⁹⁸Au for the metal phase-indicates a fast circulating movement with vortices at the ends in both phases. Circulation rates up to 100 cm per sec were observed, and an average value seemed to be 10 cm per sec. The implications of the convection on the mechanism of the secondary reactions, the dissolution of alumina in the bath electrolyte and the distribution of carbon particles in the cell are discussed.     

Requirement of Src kinase Lyn for induction of DNA synthesis by granulocyte colony-stimulating factor

Treatment of cells with granulocyte colony-stimulating factor (G-CSF) leads to tyrosine phosphorylation of cellular proteins. G-CSF stimulates both the activation of protein tyrosine kinases Lyn, Jak1, and Jak2 and the association of these enzymes with the G-CSF receptor. Wild-type, lyn-deficient, and syk-deficient chicken B lymphocyte cell lines were transfected with the human G-CSF receptor, and stable transfectants were studied. G-CSF-dependent tyrosyl phosphorylation of Jak1 and Jak2 occurred in all three cell lines. Wild-type and syk-deficient transfectants responded to G-CSF in a dose-responsive fashion with increased thymidine incorporation, but none of the clones of lyn-deficient transfectants did. Ectopic expression of Lyn, but not that of c-Src, in the lyn-deficient cells restored their mitogenic responsiveness to G-CSF. Ectopic expression in wild-type cells of the kinase-inactive form of Lyn, but not of the kinase-inactive form of Jak2, inhibited thymidine incorporation in response to G-CSF. These studies show that the absence of Lyn results in the loss of mitogenic signaling in the G-CSF signaling pathway and that activation of Jak1 or Jak2 is not sufficient to cause mitogenesis.     

Association of precipitating anti-adrenal anti-adrenal antibodies with moniliasis-polyendocrinopathy syndrome

The association of precipitating anti-adrenal antibodies with different subgroups of idiopathic Addison's disease were studied. We had previously found these antibodies in patients with the moniliasis-polyendocrinopathy syndrome. Sera of 36 adult patients suffering from different froms of Addison's disease were examined for the presence of adrenal antibodies demonstrable either by immunofluorescence (IFL) or by gel diffusion. 3 of the 17 patients with tuberculous and 17 of 19 patients with idiopathic Addison's disease had IFL antibodies but only one had precipitating antibodies. There was one typical case of Schmidt's syndrome, and four additional cases with Addison's disease combined with diabetes or thyroiditis, who may later develop the syndrome. None of htese patients had precipitating anti-adrenal antibodies. The only patients with precipitating adrenal antibodies had the moniliasis-polyendocrinopathy syndrome. He was not typical as Addison' disease appeared unusually late and he did not have hypoparathyroidism. The presence of precipitating anti-adrenal antibodies in this patient, and the absence of these in other groups of Addison's disease, is further evidence for the association of precipitating antibodies with the moniliasis-polyendocrinopathy syndrome.