New approach of semiconductor laser related technologies for ultrafast photonics

Ultrashort laser pulses offer new jump in information and communication technology. Especially semiconductor laser based ultrafast photonic devices and systems are promising. We review our new approaches for femtosecond pulse generation, and thin film technology for broad band semiconductor optical amplifiers.     

Thermogravimetric Analysis of Aromatic Polyamides with Benzimidazolyl Side Group

The TG studies are presented for isomers of benzimidazolyl-substituted polyamides (BIPA). The TG data are compared with those polyamides (PA) of identical backbones without substitution, in view of the mechanism of thermal degradation. The TG mass loss curves divided to three temperature ranges reflect the decomposition reactions in the respective temperature ranges: (1) cleavage of single bonds of nitrogen to aromatic ring, (2) random scission of single bonds, (3) condensation of the remained rings. Liberation of benzimidazole rings occurs in the temperature range (2). The final product, char, contains benzimidazole rings. Terephthaloyl-rich BIPA's retard liberation of benzimidazole from the decomposed polymer. This revised version was published online in August 2006 with corrections to the Cover Date.     

Structural Analysis of Electroplated Amorphous-Nanocrystalline Ni-W

 Ductile nickel-tungsten (Ni-W) alloys containing about 20–21 at.%W were electroplated onto copper substrates. The development of the amorphous/nanocrystalline microstructure towards a complete crystallization by isochronal heat treatments in vacuum was monitored by different methods. For medium annealing temperatures a solid-solution of W in the fcc-Ni lattice was achieved resulting in an increased hardness. For temperatures of 600 °C and upward recrystallization started and thermodynamically stable intermetallic compounds like Ni₄W and NiW were formed. A third phase, containing more than 80 at.%W was also detected but could not be identified so far. Only by combination of different methods and especially by use of analytical TEM structural analysis and phase identification in these amorphous-nanocrystalline Ni-W alloys were successful.     

A note on chordal bound graphs and posets

We study relations between induced subgraphs and (n,m)-subposets. Using properties of (n,m)-subposets, we consider a characterization of chordal double bound graphs in terms of forbidden subposets. Furthermore, we deal with properties of a poset whose double bound graph is isomorphic to its upper bound graph or its comparability graph, etc.     

On the analysis of intermediate–energy Coulomb excitation experiments

In a recent publication [C.A. Bertulani, G. Cardella, M. De Napoli, G. Raciti, E. Rapisarda, Phys. Lett. B 650 (2007) 233] the validity of analysis methods used for intermediate-energy Coulomb excitation experiments was called into question. Applying a refined theory large corrections of results in the literature seemed needed. We show that this is not the case and that the large deviations observed in above mentioned reference are due to the use of the wrong experimental parameters in that publication. We furthermore show that an approximate expression derived in above mentioned reference is in fact equivalent to the theory of Winther and Alder, an analysis method often used in the literature.     

p42MAPK-mediated phosphorylation of xEIAP/XLX in <Emphasis Type="Italic">Xenopus</Emphasis> cytostatic factor-arrested egg extracts

Background  

BIR family proteins are evolutionarily conserved anti-apoptotic molecules. One member of Xenopus BIR family proteins, xEIAP/XLX, is a weak apoptosis inhibitor and rapidly degraded in a cell-free apoptotic execution system derived from interphase egg extracts. However, unfertilized eggs are naturally arrested at the metaphase of meiosis II by the concerted activities of Mos-MEK-p42MAPK-p90Rsk kinase cascade (cytostatic factor pathway) and many mitotic kinases. Previous studies suggest that cytostatic factor-arrested egg extracts are more resistant to spontaneous apoptosis than interphase egg extracts in a p42MAPK-dependent manner. We tested whether xEIAP/XLX might be phosphorylated in cytostatic factor-arrested egg extracts, and also examined whether xEIAP/XLX could be functionally regulated by phosphorylation.     

Biradical character of linear π-conjugated oligomer dications composed of thiophene, pyrrole, and methylthio end-capping units

Combined DFT calculations and UV-vis-NIR, ESR, and SQUID measurements revealed that the ground-state electronic structure of a linear π-conjugated oligomer dication composed of two pyrrole and six or seven thiophene rings and methylthio end-capping units is dominated by a singlet biradical character.     

Test compounds for detecting the silanol effect on the elution of ionized amines in reversed‐phase LC

The effectiveness of several basic compounds for testing silica‐based stationary phases was reviewed by applying them to recent columns for reversed‐phase HPLC. Most octadecylsilylated (C18) stationary phases, prepared as a base‐deactivated material from high‐purity silica gel with endcapping, provided excellent peak shape and column efficiency for the bases including benzylamine and amitriptyline that once caused problems and were subsequently employed for testing silanol activities. However, a cyclic tertiary amine, dextrometorphan, was eluted as an acceptable peak from only a few columns at neutral pH. Such a more sensitive probe is expected to contribute to further improvement of the stationary phase for reversed‐phase HPLC.