Pressure dependence of NMR spectroscopy for studying intermolecular interactions 1H NMR in organic solvents involving the nitroxide radical

Pressure effects on ¹H chemical shifts and relaxation rates in organic solvents containing the nitroxide radical have been observed. ¹H chemical shifts with pressure and pressure-broadenings for hydrogen bonding between proton-donor molecules and the nitroxide radical have been observed.     

Theoretical analysis of correlation between ionization threshold fluence in IR‐MALDI and IR absorption spectrum of matrix molecules

To investigate the correlation between the wavelength dependence of ionization threshold fluence of target molecule in matrix‐assisted laser desorption/ionization by infrared (IR) laser and the IR absorption spectrum of matrix molecule, we have analyzed the IR absorption spectra of four matrix molecules using density functional theory and correlated ab initio molecular orbital method. The calculated IR absorption spectra of the isolated molecules showed more qualitative correlation with the wavelength dependence of ionization threshold fluence than those of the solid state structures. We can consider that a portion of matrix molecules lost the ordered crystal structure and that the transition to the diluted or isolated state occurred at the early process of IR laser irradiation. © 2012 Wiley Periodicals, Inc.     

Measurement of the total active 8B solar neutrino flux at the Sudbury Neutrino Observatory with enhanced neutral current sensitivity

The Sudbury Neutrino Observatory has precisely determined the total active (nu(x)) 8B solar neutrino flux without assumptions about the energy dependence of the nu(e) survival probability. The measurements were made with dissolved NaCl in heavy water to enhance the sensitivity and signature for neutral-current interactions. The flux is found to be 5.21 +/- 0.27(stat)+/-0.38(syst) x 10(6) cm(-2) s(-1), in agreement with previous measurements and standard solar models. A global analysis of these and other solar and reactor neutrino results yields Deltam(2)=7.1(+1.2)(-0.6) x 10(-5) eV(2) and theta=32.5(+2.4)(-2.3) degrees. Maximal mixing is rejected at the equivalent of 5.4 standard deviations.     

Characterization of preformed plasmas with an interferometer for ultra-short high-intensity laser-plasma interactions

The evolution of an Al preformed plasma produced by a prepulse was observed before and after the arrival of the main pulse by an interferometer using a femtosecond probe pulse. A central density depression due to the ponderomotive force of the main laser pulse in the preformed plasma with a 100 m scale length was clearly visible after the main pulse irradiation at an intensity of 5×10¹⁶ W/cm². The temporal profiles of the prepulse, characterized by a cross-correlation in conjunction with a precise density profile measurement by an interferometer, contribute to the better understanding of femtosecond laser-matter interactions. PACS 52.38.-r; 52.50.Jm; 52.70.-m     

Photocyclization reaction of a diarylmaleimide derivative in polar solvents

Photochromism of a symmetric diarylmaleimide derivative, having two thiophene rings (1), and a non-symmetric derivative having a S,S-dioxide thiophene ring and a thiophene ring (2) as the aryl moieties, was studied in various solvents. The photocyclization quantum yield of gradually decreased with increasing the solvent polarity and the reaction was not observed in polar solvents, such as ethanol and acetonitrile; on the other hand, such a strong solvent dependence of the photocyclization reaction was not observed for ; the different behavior is attributed to the weaker electron donating ability of the S,S-dioxide thiophene ring.     

Synthesis and biological activity of novel 5-(omega-aryloxyalkyl)oxazole derivatives as brain-derived neurotrophic factor inducers

A novel series of 5-(omega-aryloxyalkyl)oxazole derivatives was prepared and their effects on brain-derived neurotrophic factor (BDNF) production were evaluated in human neuroblastoma (SK-N-SH) cells. Syntheses were performed by construction of an oxazole ring as a key reaction. Most of the 5-(omega-aryloxyalkyl)oxazole derivatives markedly increased BDNF production in SK-N-SH cells. 4-(4-Chlorophenyl)-2-(2-methyl-1H-imidazol-1-yl)-5-[3-(2-methoxyphenoxy)propyl]-1, 3-oxazole, one of the most promising compounds, showed potent activity (EC(50)=7.9 microM) and the improvement of the motor nerve conduction velocity and the tail-flick response accompanied by a recovery of the brain-derived neurotrophic factor level in the sciatic nerve of streptozotocin (STZ)-diabetic rats.     

Doubly-bridged binuclear complexes of oxomolybdenum(V) and oxotungsten(V) containing sexadentate ligands

Binuclear oxomolybdenum(V) and oxotungsten(V) complexes of the type, [M ₂(O)₂(-X)(-X ¹)], where M=Mo, W;X.X ¹=O, S; L=edta, pdta (n=2-), tpen, tppn (n=2+) (edta^4– =ethylenediaminetetraacetate(4–), pdta=R- orR,S-propylenediaminetetraacetate(4–), tpen=N,N,N ¹,N¹-tetrakis(2-pyridyhnethyl)-ethylenediamine, and tppn=R- orR,S-N,N,N ¹,N¹-tetrakis(2-pyridylmethyl)-propylenediami ne) are reviewed with respect to their preparation, structure, spectroscopic properties, reactivities, and in particular asymmetric distortion around the bicyclo [4.1.1 ] type core and stereoselectivity related to this distortion,Dedicated to Professor Jiaxi Lu on the occasion of his 80th birthday and in recognition of his pioneering contributions.     

Spectra of graphs attached to the space of melodies

For any integer n greater than or equal to two, two intimately related graphs on the vertices of the n-dimensional cube are introduced. All of their eigenvalues are found to be integers, and the largest and the smallest ones are also determined. As a byproduct, certain kind of generating function for their spectra is introduced and shown to be quite effective to compute the eigenvalues of some broader class of adjacency matrices of graphs.     

Measurement of fallout with rain in Hiroshima and several sites in Japan from the Fukushima reactor accident

Fallout with rain from the Fukushima reactor accident was monitored for about two months in Higashi-Hiroshima City, Hiroshima, Japan, from March 20 to May 23, 2011. Gamma-ray (γ-ray) spectra measured using a low background HPGe spectrometer showed clear evidence of fission products—¹³¹I, ¹³⁷Cs, and ¹³⁴Cs. The ¹³¹I was observed on March 27 and April 8, while ¹³⁷Cs and ¹³⁴Cs were observed on March 27, April 18, and April 22. The ¹³¹I, ¹³⁷Cs, and ¹³⁴Cs activity concentrations in rainwater collected in Hiroshima reached 0.44 ± 0.09 on April 8, 0.17 ± 0.01 on April 18, and 0.15 ± 0.01 Bq/L on April 18, 2011, respectively. These activity levels were compared with global results collected from the Northern Hemisphere. Several samples of rainwater that were collected in Chiba (Kashiwa) on March 21, April 11, and May 12; Tokyo (Nerima) on March 21 and April 11; Osaka (Hirano) on April 8; Nara (Kitakatsuragi) on April 9; and Fukushima (Fukushima) on April 19, were also measured by our spectrometer and compared. Among these samples of rainwater collected at different locations in Japan, the one collected at Kashiwa City, Chiba Prefecture, on March 21 showed the highest activity concentrations of 6072 ± 1,   632 ± 4,   766 ± 3,   637 ± 1,   97.6 ± 0.8, and 752 ± 2 Bq/L for ¹³¹I,   ¹³²I,   ¹³²Te,   ¹³⁴Cs,   ¹³⁶Cs, and ¹³⁷Cs, respectively. The health risks due to these high activity levels were considered in terms of several regulations. The ratio of the activites for the isotopes ¹³¹I to ¹³⁷Cs and ¹³⁴Cs to ¹³⁷Cs were compared with the other measurements and discussed.