Preparation and properties of molybdenum and tungsten dinitrogen complexes : `XVI. Electrochemical properties of tungsten and molybdenum diazoalkane complexes

Diazoalkane complexes of type [MF(NNCRR′)(dpe)₂][BF₄] (M = Mo or W; dpe = Ph₂PCH₂CH₂PPh₂), which are easily derived from bis(dinitrogen) complexes [M(N₂)₂(dpe)₂], undergo consecutive one- and two-electron oxidations and reductions under voltammetric conditions at a platinum electrode. The ESR spectra of the species generated by the controlled potential electrolysis show that primary oxidation occurred on the metal atom (M = Mo) and reduction on the two nitrogen atoms in the diazoalkane ligands (M = Mo or W).     

Reactions of palldium(II) compounds with carbon monoxide in alcohol/amine systems : a new route to palladium(O) carbonyl and carboalkoxy-palladium(II) complexes

Palladium(O) carbonyl complexes, Pd(CO)(PPh₃)₃ Pd₃(CO)₃(PPh₃)₃ and Pd₃(CO)₃(PPh₃)₄, can conveniently be prepared by the reaction of (PPh₃)₂PdCl₂ with carbon monoxide at room temperature in methanol/amine systems involving primary and secondary amines such as diethylamine and cyclohexylamine. These carbonyl complexes are interconvertible under suitable conditions. On the other hand, use of tertiary amine such as triethylamine and tri-n-butylamine in place of the above amines give selectively a carbomethoxy complex (PPh₃)₂PdCl(COOCH₃).     

Prolongation of life span of stroke-prone spontaneously hypertensive rats (SHRSP) ingesting persimmon tannin

The effects of persimmon tannin on pathophysiological changes in stroke-prone spontaneously hypertensive rats (SHRSP) were investigated. When the persimmon tannin was chronically ingested by SHRSP, the life span was significantly prolonged, yet the effect on blood pressure was slight. The incidences of brain hemorrhage and infarction were also significantly decreased by this treatment. To elucidate the mechanisms involved in these events, the effects of condensed tannins, including persimmon tannin, on free radicals and lipid peroxidation were examined in vitro. Using electron spin resonance analysis, we found that these tannins have a potent, concentration-dependent scavenging action toward active oxygen free radicals. These tannins strongly inhibited lipid peroxidation in rat brain homogenates, in a concentration-dependent manner. Persimmon tannin inhibited lipid peroxidation similarly to (-)-epigallocatechin. Persimmon tannin was 20 times more effective than alpha-tocopherol in terms of the 50%-inhibitory concentration. The radical scavenging action and inhibition of lipid peroxidation by persimmon tannin may explain, in part, the prolongation of the life span of the SHRSP ingesting persimmon tannin.     

Synthesis of optically active forms of seudenol,the pheromone of douglas fir beetle

(R)-(+)-Seudenol (3-methylcyclohex-2-en-1-ol) and its antipode were synthesized from optically active forms of 3-iodocyclohex-2-en-1-ol by treatment with Me₂CuLi. Their absolute configurations were determined by converting (+)-3-iodocyclohex-2-en-1-ol to the known (R)-(+)-cyclohex-2-en-1-ol.     

Electron spin resonance of phosphorescent triplet molecules observation of the proton hyperfine structure of Δm = ±2 transitions in stretched poly (vinyl alcohol) films

By applying a microwave magnetic field parallel to an external magnetic field, ESR of naphthalene, quinoxaline, quinoline and isoquinoline in their phosphorescent triplet states has been studied at 77 K. The proton hyperfine structures in the Δm = ± 2 transitions were distinctly resolved, especially when the stretched film was used as a host, compared with observations in ethanol glasses. The assignment of these ESR signals was carried out with the aid of the stretched-film method.     

In situ STM imaging of surface dissolution and rearrangement of a Pt-Fe alloy electrocatalyst in electrolyte solution

The formation of a Pt skin layer with predominantly (111)-oriented facets induced by dissolution of Fe atoms in a Pt-Fe alloy for fuel cell applications is investigated for the first time by using in situ electrochemical STM in 0.1 M HClO4 solution.     

Nuclear propelled vessels and neutrino oscillation experiments

We study the effect of naval nuclear reactors on the study of neutrino oscillations. We find that the presence of naval reactors at unknown locations and times may limit the accuracy of future very long baseline reactor-based neutrino oscillation experiments. At the same time, we argue that a nuclear powered surface ship such as a large Russian icebreaker may provide an ideal source for precision experiments.     

The Change of Grip Strength in a Patient with Congenital Myotonic Dystrophy Over a 4-year Period

Myotonic dystrophy (MyD) is a neuromuscular disease that is autosomal dominant and the most common form of muscular dystrophy affecting adults. The clinical features of MyD include a multisystemic disorder characterized by myotonia, progressive muscle weakness and wasting, cataracts, premature balding and mental retardation. The most severe type of MyD is classified as congenital MyD (CMyD). The muscle weakness in CMyD is very severe, but muscle development can be observed in the period of growth. However, no clinical case of this type has been reported yet. Therefore, we report on a girl with CMyD who had an increase in muscle strength over a four-year period. The girl with CMyD participated in this study from the age of 9 to the age of 12. The measurement of muscle strength was recorded as the maximum score of grip strength with the use of dynamometers. Grip strength was assessed once a year by the same two physical therapists. Grip strength of CMyD for each year was markedly weak when compared with the normal controls, but muscle strength changed within some specific growth areas. The muscle weakness in CMyD was remarkable, but the result showed that specific muscle strength of CMyD in childhood was actually increased.     

An anomalous emission excited near the absorption edge of pyrene crystals

Emission spectra and decay times of the fluorescence excited at the absorption edge region in pyrene crystals were measured. At liquid nitrogen temperature, the fluorescence under the excitation at 390 nm is considered as the excimer emission and its band peak shifts a little to the short wavelength in comparison with that of the excimer emission under the excitation at 360 nm. The emission decay times under the excitation at the 390 nm and 360 nm are about 155 ns and 180 ns, respectively, at liquid nitrogen temperature. The former decay time changes its value abruptly near 127 K. This abrupt change of the decay time may be due to the phase transition in pyrene crystals.