Effect of rotational relaxation on the intensity and polarization of fluorescence emission caused by sequential two-photo excitation

General formulas are derived for the intensity and the degree of polarization of the S_m-fluorescence emission (m ? 2) of a sample excited by the sequential two-photon excitation process (S_n ← S₁ ← S₀, n ? 2) with plane-polarized pulsed light. They show how the S_m-fluorescence intensity and anisotropy depend on the relative orientation of the relevant transition dipoles within a molecule and on the degree of rotational relaxation of molecules in the intermediate state (S₁) and in the S_m state (for the case m = n), or in the S_n → S_m process (m ≠ n).     

Total synthesis of (+)-pedamide. A new,remote controlled asymmetric induction

Total synthesis of optically active pedamide $\text{2}$, one of the tetrahydropyran moieties of the potent insect poison pederine $\text{1}$, was achieved by employing a new, remote controlled asymmetric reduction of a ketone as key step.     

Observation of antinormally ordered Hanbury Brown-Twiss correlations

We have measured antinormally ordered Hanbury Brown-Twiss correlations for coherent states of the electromagnetic field by using a stimulated parametric down-conversion process. Photons were detected by stimulated emission, rather than by absorption, so that the detection responded not only to actual photons but also to zero-point fluctuations via spontaneous emission. The observed correlations were distinct from normally ordered ones as they showed excess positive correlations, i.e., photon bunching effects, which arose from the thermal nature of zero-point fluctuations.     

Identification of Arabidopsis genes regulated by high light-stress using cDNA microarray

In plants, excess light has the potential to damage the photosynthetic apparatus. The damage is caused in part by reactive oxygen species (ROS) generated by electrons leaking from the photosynthetic electron transport system. To investigate the mechanisms equipped in higher plants to reduce high light (HL) stress, we surveyed the response of 7000 Arabidopsis genes to HL, taking advantage of the recently developed microarray technology. Our analysis revealed that 110 genes had a positive response to a 3 h treatment at a light intensity of 150 W m(-2). In addition to the scavenging enzymes of ROS, the genes involved in biosynthesis of lignins and flavonoids are activated by HL and actually resulted in increased accumulation of lignins and anthocyanins. Comparing the HL-responsive genes with drought-inducible genes identified with the same microarray system revealed a dense overlap between HL- and drought-inducible genes. In addition, we have identified 10 genes that showed upregulation by HL, drought, cold and also salt stress. These genes include RD29A, ERD7, ERD10, KIN1, LEA14 and COR15a, most of which are thought to be involved in the protection of cellular components.     

On finite -submodules of Selmer groups of elliptic curves

In this note, we give another proof of a result of R. Greenberg on the non-existence of non-trivial finite -submodules of Selmer groups.

     

Experimental and Numerical Analysis of Thermal Deformation of Electronic Packages,QFP and MCM

0Introduction Anelectronicpackageisgenerallyconstructedwithanactivesiliconchip,mountisland,gold wires,leadframesandsoldersasshowninFig.1(a).Toprotectfromtheenvironment,thesilicon chipisusuallyencapsulatedinresin.SincethesematerialshavedifferentCTE(coefficientofthermal expansion),stressandstrainaregeneratedbyinternalheatinginserviceoperationorthermalloading fromtheenvironment[1].Insomecases,thismaycausefailureofthewireandcrackinganddebonding insidethepackage.Thereliabilityofelectronicpackages…     

Development of a numerical wave tank for analysis of nonlinear and irregular wave field

A numerical wave-absorption filter has been developed for an open boundary condition in the analysis of nonlinear and irregular wave evolution. The filter is composed of a simulated sponge layer and Sommerfeld's radiation condition at the outer edge of the layer. The wave-absorption characteristics of the filter have been investigated by applying the linear potential theory and a two-dimensional nonlinear boundary element model. In both cases, the filter is found to he applicable for a wide range of wave parameters. In order to realize an idealized “numerical wave tank”, the present model also incorporates a nonreflective wave generator in the computational domain composed of a series of vertically aligned point sources. Numerous numerical experiments demonstrate that the present approach is effective in generating an arbitrary wave profile without reflection not only at the open boundaries but also at the wave generator.     

Stimulated Brillouin scattering and its dependences on strain and temperature in a high-delta optical fiber with F-doped depressed inner cladding

Stimulated Brillouin scattering (SBS) in a high-delta fiber with F-doped depressed inner cladding is studied through considering the interaction of acoustic and optical modes in the fiber. It is found that the number of acoustic modes in the fiber is reduced and the frequency spacing between neighboring modes is enlarged because of the F doping. The dependences of SBS on strain and temperature are measured and compared for each acoustic mode to investigate the feasibility of discriminative sensing of strain and temperature by use of the fiber.     

Arginine improves protein elution in hydrophobic interaction chromatography. The cases of human interleukin-6 and activin-A

The effects of arginine on protein binding and elution in hydrophobic interaction chromatography (HIC) were examined using recombinant human interleukin-6 (IL-6) and activin-A. Binding of IL-6 in the presence of ammonium sulfate (AS) was tested using low- and high-substituted phenyl-sepharose. While inclusion of arginine during loading of IL-6 resulted in incomplete binding to the low-substituted phenyl-sepharose, binding was complete to the high-substituted phenyl-sepharose. Arginine facilitated elution of IL-6 from both columns. These results demonstrate that arginine weakens hydrophobic interactions between IL-6 and the phenyl-sepharose. More drastic results were obtained using activin-A, which showed undetectable recovery from phenyl-sepharose. Although no apparent elution of activin-A was observed from butyl-sepharose in aqueous buffer alone, the addition of arginine to the buffer resulted in partial elution recovery and, together with ethanol, resulted in greatly improved recovery of the protein. Two arginine derivatives, acetylarginine and agmatine, were also effective. These results show that arginine improves protein elution in HIC.     

Synthesis and fluorescence of 2h‐pyrone derivatives for organic light‐emitting diodes (OLED)

2H‐Pyrone derivatives were synthesized through the reaction of aryl acetyl compounds with ketene dithioacetals in the presence of sodium hydroxide, and they showed very strong fluorescence in the solid state. The light‐emitting region of these 2H‐pyrones is 447‐630 nm in the solid states.