Time Courses and Time‐Resolved Spectra of Firefly Bioluminescence Initiated by Two Methods of ATP Injection and Photolysis of Caged ATP

The time‐dependent characteristics of firefly bioluminescence initiated by manual injection of adenosine triphosphate (ATP) into buffer solution containing luciferin (Ln), luciferase (Luc) and Mg²⁺ were measured with a resolution of 10 ms, and compared with those obtained by photolysis of caged ATP. The time course depends on pH; both rise and decay rates decrease when pH is lowered from 7.8 to 6.8. In contrast, the parameter λ in the kinetic formula related to diffusion of ATP is almost independent of pH. The pH dependence of the time course of bioluminescence can be explained by the same pH tendency as the rate of ATP binding at the active site of Luc. The time‐resolved spectra can be decomposed into two Gaussian components with maxima at 2.2 and 2.0 eV. At pH 7.8, the band at 2.2 eV is more intense than that at 2.0 eV for all three concentration conditions. At lower pH, the band at 2.2 eV becomes weaker than that at 2.0 eV. The intensity ratio of the 2.0 and 2.2 eV bands is constant for duration time of 600 s for both injection and photolysis experiments, and the above conclusions are unaffected by the concentration ratio [Ln]/[Luc].     

Synthesis and Photocatalytic Property of Hectorite/(Pt,TiO2) and H4Nb6O17/(Pt,TiO2) Nanocomposites

Abstract

TiO₂ and Pt have been intercalated in hectorite and H₄Nb₆O₁₇. The height of TiO₂ and Pt pillars was less than 0.8 nm and the band gap energy of TiO₂ pillars was ca. 3.3 eV. Both hectorite/TiO₂ and H₄Nb₆O₁₇(Pt, TiO₂) were capable of hydrogen evolution following irradiation from a high pressure mercury are (λ > 290 nm) in the presence of methanol as a sacrificial hole acceptor and the hydrogen evolution was enhanced by co-incorporation of Pt, although hectorite and hectorite/Pt did not show photocatalytic activity. Incorporation of Pt or Pt and TiO₂ in the interlayer of H₄Nb₆O₁₇ has resulted in enhanced photo evolution of hydrogen, however, TiO₂ alone in the interlayer of H₄Nb₆O₁₇ showed adverse photocatalytic activity.     

Three-dimensional visualization of columnar vortices in rotating Rayleigh–Bénard convection

Journal of Visualization -  To enrich the three-dimensional experimental details of vortex structures in rotating Rayleigh–Bénard convection, we established a technique...     

A Novel Reactivity of Phosphanylalumane (>P−Al<): Reversible Addition of a Saturated Interelement Bond to Olefins

The reversible addition of olefins to a phosphanylalumane, P−Al single-bond species, was investigated. The P−Al bond added to ethylene and relatively small terminal alkenes (propylene and hex-1-ene) at room temperature to give the corresponding alkene adducts. Heating the terminal alkene adducts released the corresponding alkenes and regenerated the P−Al bond, but no release of ethylene was observed even under vacuum conditions. The reactivity of ethylene adduct as a new saturated C₂ vicinal P/Al-based FLP was also investigated. The ethylene adduct was found to undergo complexation with nitriles to give the corresponding nitrile adducts to the Al center, which retained the ethylene tether as in the case of the corresponding P/B-based FLP. However, the reactivity of ethylene toward CO₂ and benzaldehyde differed from that of the P/B system giving the corresponding adducts.     

Copper–Oxygen Dynamics in the Tyrosinase Mechanism

The dinuclear copper enzyme, tyrosinase, activates O₂ to form a (μ-η²:η²-peroxido)dicopper(II) species, which hydroxylates phenols to catechols. However, the exact mechanism of phenolase reaction in the catalytic site of tyrosinase is still under debate. We herein report the near atomic resolution X-ray crystal structures of the active tyrosinases with substrate l -tyrosine. At their catalytic sites, CuA moved toward l -tyrosine (CuA1 → CuA2), whose phenol oxygen directly coordinates to CuA2, involving the movement of CuB (CuB1 → CuB2). The crystal structures and spectroscopic analyses of the dioxygen-bound tyrosinases demonstrated that the peroxide ligand rotated, spontaneously weakening its O−O bond. Thus, the copper migration induced by the substrate-binding is accompanied by rearrangement of the bound peroxide species so as to provide one of the peroxide oxygen atoms with access to the phenol substrate's ϵ carbon atom.     

Champion data comparison in nuclear research institutes in Europe,the U. S., and Japan

Bibliometric analysis was carried out for champion data comparisons among prestigious nuclear research institutes (PNRI) existed in Japan, the U. S., France, and Germany. The analysis was relied on database INIS (IAEA), ECD (DOE), WOS (Thomson), and SCOPUS (Elsevier). INIS is advanced, key ex-post evaluating tool for determining general research paper-based champion. Over the 30-year time span of research paper publication, the world champion among 11 PNRI is JAERI confirmed by INIS but ORNL confirmed by ECD, WOS, and SCOPUS, the latter two collected journal submitted research paper. Five years ago JAERI is the 3rd ranked institutes following ORNL and ANL. INIS database results revealed that CEA/Grenoble is the French domestic champion regarding research paper publication. Five years ago it was CEA/Saclay. Results from analytical tools used in bibliometric studies should be viewed with careful consideration to learn of any influencing factors because different characteristics exhibited by individual databases can sometimes generate conflicting bibliometric results. This was true among INIS, ECD, WOS, and SCOPUS when looking at trends especially between 5-year periods.     

Study of Proton Resonances in ~(22)Mg by Resonant Elastic Scattering of ~(21)Na+p and Its Astrophysical Implication in ~(18)Ne(α,p)~(21)Na Reaction Rate

Proton resonant states in ~(22)Mg have been investigated by the resonant elastic scattering of ~(21)Na+p.The ~(21)Na beam with a mean energy of 4.00 MeV/u was separated by the CNS radioactive ion beam separator(CRIB) and bombarded a thick(CH_2)_n target.The energy spectra of recoiled protons were measured at scattering angles of θ_(cm)～172° and 146°,respectively.A new state at 7.06 MeV has been observed clearly and another new one at 7.28 MeV is tentatively identified due to its low statistics.The proton resonant parameters were deduced from an R-matrix analysis of the differential cross section data.The astrophysical resonant reaction rate for the ~(18)Ne(α,p) ~(21)Na reaction has been estimated,and it is about five times larger than that assumed before.     

Novel potassium channel activators. II. Synthesis and pharmacological evaluation of 3,4-dihydro-2H-1,4-benzoxazine derivatives: modification of the aromatic part.

Three new series of analogues related to 3,4-dihydro-2H-1,4-benzoxazine derivative 1a were synthesized and evaluated for their potassium channel activating activity. In the first series I, where the 6,7-positions were disubstituted, it was found that an electron-withdrawing substituent was preferable at the 6 position, but either an electron-withdrawing or releasing substituent without bulkiness was tolerated at the 7 position. In the second series II, where several heterocycles were introduced into the 6,7-positions, the oxadiazole derivative 6 showed more potent activity than cromakalim. In the third series III, where the benzene ring was replaced by a pyridine ring, borane complex 16 had equivalent activity to cromakalim. Especially, compound 6 showed a potent hypotensive effect with a long duration of action in the spontaneous hypertensive rat and had a lesser increasing effect on intracranial pressure in dogs than 1a and levcromakalim, showing a good profile as an antihypertensive agent.     

Orthorhombic B2CN crystal synthesized by high pressure and temperature

B_0.54C_0.28N_0.18 precursor powder with turbostratic structure was prepared by using melamine and boric acid. The precursor was transformed into orthorhombic B₂CN under definite high pressure and temperature conditions. The composition of the orthorhombic B₂CN powder is B_0.47C_0.23N_0.30. Its lattice parameters are a=0.4776 nm, b=0.4585 nm and c=0.3629 nm. A strong absorption band from 1088 to 1385 cm⁻¹ of orthorhombic B₂CN was observed by infrared measurement. In the photoluminescence (PL) spectrum of orthorhombic B₂CN powder measured at room temperature, a broad peak corresponding to its band-edge emission centers at 374 nm.     

Massless and quantized modes of kinks in the phase space of superconducting gaps

We investigated quantized modes of kinks in the phase space of superconducting gaps in a superconductor with multiple gaps. The kink is described by the sine-Gordon model in a two-gap superconductor and by the double sine-Gordon model in a three-gap superconductor. A fractional-flux vortex exists at the edge of the kink, and a fractional-flux vortex will be stable in a three-gap superconductor with time-reversal symmetry breaking. The kink and fractional-flux vortex exhibit massless modes as a sliding motion. We show further that there are one zero-energy mode (massless mode) and quantized excitation modes in kinks, which are characteristic features of multi-gap superconductors. The equation of quantized modes for the double sine-Gordon model is solved numerically. The correction to the ground-state energy is calculated based on the renormalization theory.