A new level at 192.5 keV in Ge

In the experiments on ⁷⁴Ge(d, pγ)⁷⁵Ge, a 52.5±0.1 keV γ-ray was found in ⁷⁵Ge with a half-life of 216±5 ns. From the analysis of the γ-ray spectra the conversion coefficient of the 52.5 keV γ-ray was determined. Then, a new level of is confirmed to exist at 192.5 keV. The reduced transition probabilities of the 52.5 keV transition are deduced to be (6.9^+5.6 _−2.1) × 10⁻⁵ for B(M1) and 31⁺³ ₋₂ for B(E2) in Weisskopf units.     

A rotational band in82Zr

The neutron deficient nucleus⁸²Zr has been studied through the reaction⁵⁸Ni(²⁸Si, 2p 2n)⁸²Zr with a calculated cross section of 0.3% of the total fusion cross section atE(²⁸Si)=128 MeV. Gamma rays from excited states of⁸²Zr were measured and identified using the NORDBALL escape-suppression array at the Niels Bohr Institute. Reaction channel selection was performed by use of neutron and charged particle detector arrays in conjunction with the germanium detectors. A rotational band in⁸²Zr has been identified with spins up to 20 ? by analysis of reaction channel selectedγ-γ coincidence matrices. Band crossings were identified at frequencies 0.57 and 0.69 MeV.     

Enhancement effect of high-frequency noise of injection lasers with reflected waves due to direct modulation

It is found experimentally that the high-frequency noise of an injection laser associated with wave injection due to external reflection is significantly increased when the direct modulation is applied. It is clarified that the noise enhancement effect is caused by the increasing of the quantum shot noise of the injection laser due to the current modulation. The high- frequency noise of the narrow stripe laser is smaller than that of the wide stripe laser.     

Three-variable reversible Gray-Scott model

Even though the field of nonequilibrium thermodynamics has been popular and its importance has been suggested by Demirel and Sandler [J. Phys. Chem. B 108, 31 (2004)], there are only a few investigations of reaction-diffusion systems from the aspect of thermodynamics. A possible reason is that model equations are complicated and difficult to analyze because the corresponding chemical reactions need to be reversible for thermodynamical calculations. Here, we introduce a simple model for calculation of entropy production rate: a three-variable reversible Gray-Scott model. The rate of entropy production in self-replicating pattern formation is calculated, and the results are compared with those reported based on the Brusselator model in the context of biological cell division.     

Formation, deactivation and transformation of stereospecific active sites on TiCl4/dibutylphthalate/Mg(OEt)2 catalyst induced by short time reaction with Al-alkyl cocatalyst

Formation, deactivation and transformation of stereospecific active sites on TiCl₄/dibutylphthalate (DBP)/Mg(OEt)₂ Ziegler–Natta catalyst induced by short time reaction with triethylaluminum (TEA) cocatalyst (with TEA pretreatment time from 0 to 600 s) were investigated by stopped-flow propene polymerization combined with temperature rising elution fractionation (TREF) and GPC methods. It was demonstrated that both formation and deactivation of active sites with broad multiplicity in isospecificity on the catalyst are slow reactions with an induction period of ca. 0.2 s. It was most important to find that the formation of active sites with the highest isospecificity strongly depends on the interaction between the catalyst and cocatalyst (up to 60 s of pretreatment) even in the presence of internal donor. This newly observed phenomenon (according to our knowledge) suggested that the transformation of monometallic active sites (aspecific or less isospecific) into bimetallic active sites (highly isospecific) through reversible complexing with TEA cocatalyst (or its reaction product diethylaluminum chloride (DEAC)) in Ziegler–Natta catalysts cannot be overlooked even in the presence of internal electron donor. The existence of –OC₂H₅ ligand in the catalyst most probably gave birth to a new group of active titanium species. The stability of active sites increases with increasing isospecificity in the early stage of pretreatment (up to 60 s of pretreatment). While all the active sites became relatively stable in the later stage of pretreatment (from 60 to 600 s of pretreatment). The extraction of internal donor DBP by TEA from the catalyst within the pretreatment procedure is found to initiate from 60 s of pretreatment resulting in slight transformation of isospecific active sites into aspecific sites.     

VISUALIZATION OF ULTRAVIOLET LIGHT-INDUCED THYMINE DIMERS IN DNA BY IMMUNOELECTRON MICROSCOPY

Abstract— To see the damage of DNA due to ultravoilet-B more distinctly, immunoelectron microscopic studies using a monoclonal antibody against cyclobutane-type thymine dimers were performed. As a result, we could detect the existence of thymine dimers on human genomic DNA and _pUC18 plasmid DNA visually. This technique can be useful to locate the photoproducts formed on DNA.     

Orientation of dye molecules in DNA-based films with chain alignment and judgment of their DNA-binding modes

Novel composite films of chain-oriented DNA, which contain the DNA-binding dyes aligned in specific orientation, were successfully prepared by drying the solution under a horizontal magnetic field. Most of the dye-DNA composite films showed linear dichroism, as revealed by polarized ultraviolet-visible (UV-vis) spectroscopy. The intercalators, ethidium bromide and acridine orange, were fixed in chain-oriented DNA films in a similar binding manner as in solutions. Also, Hoechst 33258 and 4',6-diamidino-2-phenylindole were found to be aligned along the minor groove, even in the solid films. Thus, our new method of preparing dye-DNA composite films with chain orientation is useful for aligning small molecules, and it will provide views of the novel anisotropic materials expected in various application fields. We used this method to prepare composite DNA films with newly designed original compounds. Seven of nine dyes were judged to bind obviously to DNA as intercalators by polarized UV-vis spectroscopy. The DNA-binding manners were further analyzed by fluorescence anisotropy measurements. On the basis of the curves for the rotational angle dependence of the anisotropy, we were able to estimate the angles between the transition-dipole moments of dyes and the aligned chain axis of DNA. Interestingly, two original compounds were found to be in the tilted forms with regard to the plane of base pairs. We emphasize here that the method using aligned dye-DNA films is very convenient for identifying the binding modes of the compounds for double-stranded DNA.     

Distribution of cyclic species in network formation: Microscopic theory of branching process in Ag-R-B f−g model

The distribution of cyclic species is explored for an irreversible A_g-R-B_f-g model on the basis of the concept of the “m tree” which was introduced in a preceding report by the authors. On the assumption of equal reactivity, the explicit solution is derived; i.e., for a sufficiently concentrated solution the concentration of cyclicj-mers can be expressed as \(\left[ {R_j } \right] = \left( {k_{Rj} /k_L } \right)\left[ {\left( {f - g} \right)D_B } \right]^j \omega _j /j\) , wherek _Rj andk _L are the rate constants of cyclicj-mer formation and interconnection, respectively, and $$\omega _j = \sum\limits_{k = 0}^{[j/2]} {\left( {_{2k}^j } \right)} \alpha ^k $$ where α=(g ? 1)(f ? g ? 1)/g(f ? g) and [j/2] is the Gauss' symbol. Forg → 1, ω_j → 1, so that the solution reduces to the A-R-B_f?1 case. At a critical point one observes the strong divergence of the chances ∑ φ_j of cyclization.