New sterols from two edible mushrooms, Pleurotus eryngii and Panellus serotinus

Two edible mushrooms, Pleurotus eryngii and Panellus serotinus, have been investigated chemically. Two new sterols, 5alpha,9alpha-epidioxy-8alpha,14alpha-epoxy-(22E)-ergosta-6,22-dien-3beta-ol (1) and 3beta,5alpha-dihydroxyergost-7-en-6-one (2), have been isolated from P. eryngii, together with six known ones (3-8). Compound 1 was also isolated from P. serotinus. The structures of the new compounds were elucidated on the basis of their spectral data.     

Spontaneous copolymerization of 1,3-cycloheptadiene with acrylonitrile in the presence of zinc chloride

The reaction of 1,3-cycloheptadiene (1,3-CHpD) with acrylonitrile (AN) in the presence of ZnCl₂ leads spontaneously to the simultaneous formation of an alternating copolymer and a small amount of cycloadduct. The copolymer has a predominantly cis-1,4-structure. The formation of the charge—transfer complex between 1,3-CHpD and (AN)c (AN coordinated to ZnCl₂) in AN was detected by ultraviolet (UV) spectroscopy. The activation energies for the cycloaddition and for the copolymerization under the conditions used were determined to be 17.6 (in the presence of 1,1-diphenyl-2-picrylhydrazyl) and 16.3 kcal/mole, respectively. The rate of copolymerization in AN was found to depend on the 1.5th power of the concentrations of (AN)c and of 1,3-CHpD. Oxygen and UV irradiation causes an acceleration of the copolymerization only. On the basis of these results the mechanism of the spontaneous copolymerization is discussed and its relation to the cycloaddition in systems of 1,3-cyclodienes and AN in the presence of ZnCl₂ is mentioned.     

Sterol constituents from two edible mushrooms, Lentinula edodes and Tricholoma matsutake

Two new sterols, (22E)-23-methylergosta-5,7,22-trien-beta-ol (1) and 5alpha,6alpha-epoxy-(22E)-ergosta-8,14,22-triene -3beta,7alpha-diol (2), have been isolated from two edible mushrooms, Lentinula edodes and Tricholoma matsutake, respectively, together with twelve known ones (3-14). The structures of the new compounds were elucidated on the basis of their spectral data.     

Resistance fluctuations in integer quantum-Hall transitions

We have studied the resistance fluctuations (RF) in integer quantum-Hall transitions for high-mobility two-dimensional electron gas systems. The role of coherence in RF is examined by investigating the conductance through two scattering regions, that are spatially separated but interfere quantum-mechanically with each other. The phase coherence does not play a substantial role in determining the pattern of RF, whereas it affects the amplitude of RF.     

Effects of digital processing on repeatability assessment of a multiple reaction monitoring liquid chromatography–tandem mass spectrometry system by ISO 11843-7

ISO 11843 part 7 (ISO 11843-7) can provide a standard deviation (SD) of area measurements of a target peak through the stochastic behaviors of instrumental noises. The purpose of this study is to demonstrate that ISO 11843-7 can be applied to assess repeatability in an isocratic liquid chromatography–tandem mass spectrometry (LC–MS/MS) system without repetitive measurements. The relative standard deviation (RSD) of the peak area of ergosterol picolinyl ester, which was used as an example, on a multiple reaction monitoring (MRM) chromatogram was determined by ISO 11843-7. The RSD by ISO 11843-7 (N = 1) was within a 95% confidence band of the RSD by repetitive measurements (N = 6). Moreover, the effects of digital smoothing, such as moving average, were also examined on the repeatability assessment in LC–MS/MS by ISO 11843-7. From the results of the comparisons of the RSDs obtained by ISO 11843-7 and the repetitive measurements, it was shown that suitable RSDs of the peak area were obtained from the smoothed MRM chromatograms by the moving average for narrow data point windows (e.g., one-sixth of the peak width). In conclusion, the utility of repeatability assessment based on ISO 11843-7 has been expanded for the validation of an LC–MS/MS system.     

Four New Lignan Glycosides from Osmanthus fragrans Lour. var. aurantiacus Makino

Four new tetrahydrofuranoid lignan glycosides, (7S,8R,7′R,8′S)‐4,9,4′,7′‐tetrahydroxy‐3,3′‐dimethoxy‐7,9′‐epoxylignan 9‐O‐β‐D ‐glucopyranoside ( 2 ), (7R,8S,7′S,8′R)‐4,9,4′,7′‐tetrahydroxy‐3,3′‐dimethoxy‐7,9′‐epoxylignan 9‐O‐β‐D ‐glucopyranoside ( 3 ), (7R,8S,7′R,8′S)‐4,9,4′,9′‐tetrahydroxy‐3,3′‐dimethoxy‐7,7′‐epoxylignan 9‐O‐β‐D ‐glucopyranoside ( 4 ), and rel‐(7R,8S,7′S,8′R)‐4,9,4′,9′‐tetrahydroxy‐3,3′‐dimethoxy‐7,7′‐epoxylignan 9‐O‐β‐D ‐glucopyranoside ( 5 ), and ten known lignan glycosides, 1 and 6 – 14 , were isolated from the leaves of Osmanthus fragrans Lour. var. aurantiacus Makino . Their structures were established on the basis of spectral and chemical studies.     

Acetate reduction synthesis of Sr2Si5N8:Eu phosphor and its luminescence properties

A novel synthesis method was developed for the efficient red phosphor, Eu²⁺-activated Sr₂Si₅N₈, by employing the strontium acetate as both the reducing agent and strontium source. The phase purity of final product was strongly dependent on the heating rate of the precursors. Sr₂Si₅N₈:Eu²⁺ (2 at%) phosphor presented a broadband excitation spectrum in the range 300–500 nm, matching well with the blue emission (400/460 nm) of current InGaN light-emitting diodes (LEDs). The red emission peaking at 619 nm gave the relatively high (about 155%) intensity compared with the Y₃Al₅O₁₂ (YAG) (P46-Y3) standard phosphor. In addition, the saturated chromatic coordinates (0.638, 0.359) allowed it a promising candidate as a red phosphor in white LEDs application for illumination or display.     

Medicinal carbon tablets for treatment of acetaminophen intoxication: adsorption characteristics of medicinal carbon powder and its tablets

Adsorption characteristics of medicinal carbon powder (JP 14) for acetaminophen were examined at 37 degrees C using conventional incubation in an attempt to obtain an effective oral dosage form. Hydroxypropyl cellulose (HPC) and maltitol (MT), being able to act as a binding agent, were tested as additives. Tablets of medicinal carbon were produced by the wet granulation method. The rate and extent of adsorption of the medicinal carbon powder were roughly similar in water, JP 14 1st fluid (pH 1.2) and JP 14 2nd fluid (pH 6.8). The relationship between concentrations of free and adsorbed acetaminophen indicated that the adsorption followed the Langmuir mode. The maximal adsorption of acetaminophen in water was 0.219 g per gram medicinal carbon powder, little influenced by the addition of MT, but slightly reduced by the addition of HPC. The tablet prepared using MT as a binding agent displayed a favorable hardness and adequate disintegration time. The tablet showed good adsorption potential for acetaminophen, though the adsorption rate and extent of the tablet were reduced to some extent as compared with powder.     

Ubiquitous V-shape density of states in a mixed state of clean limit type II superconductors

It is demonstrated theoretically and experimentally that the low energy density of states N(E) is described by a singular V-shape form N(E)=N(0)(H)+alpha|E|+O(E2) for all clean superconductors in a vortex state, irrespective of the underlying gap structure. The linear term alpha|E| which has not been recognized so far is obtained by exactly evaluating the vortex contribution. Based on microscopic Eilenberger theory N(E) is evaluated for the isotropic gap, line, and point-node gaps to yield a V-shape N(E). Scanning tunneling spectroscopy-STM experiments on NbSe2 and YNi2B2C give direct evidence for this. We provide arguments on the significance of this finding and on the relevance to other experiments.