Distribution and densitometry mapping of L1-CAM Immunoreactivity in the adult mouse brain – light microscopic observation

Background  

The importance of L1 expression in the matured brain is suggested by physiological and behavioral studies showing that L1 is related to hippocampal plasticity and fear conditioning. The distribution of L1 in mouse brain might provide a basis for understanding its role in the brain.     

Diffraction efficiency increase by corona discharge in photoinduced surface-relief gratings on an azo polymer film

The diffraction efficiency of a surface-relief grating (SRG) was dramatically increased by corona discharge. We fabricated this SRG by applying surface modulation to azo polymer films, using laser interference fringes. The electric charge was deposited upon the SRG by a corona discharge in an oven. The first-order diffraction efficiency measured before and after corona discharge above the glass-transition temperature increased from ~2% to ~40% in a SRG written with a circularly polarized beam. The relief depth of the SRG as measured with an atomic-force microscope also increased, from ~130 nm to ~450 nm. The increase in diffraction efficiency was independent of the writing polarization.     

Electron emission from surfaces of alkali halides under the impact of metastable helium and neon atoms

Energy distributions of the electrons ejected from the evaporated film surfaces of LiF, LiCl, LiBr, NaF and NaCl by the impact of metastable He and Ne atoms have been measured. The observed distribution curves have two distinct structures: one peak is identified as the valence band structure caused by Penning ionization, while the other peak is ascribed to scattered electrons. The positions of the valence band peaks are shifted to lower ionization energy from the corresponding photoelectron peaks (by 0.1–1.5 eV depending on the substance). In contrast to the photoelectron spectra, the structure attributable to conduction bands appears only very weakly. The relative intensity of the peak caused by scattered electrons is either strong or weak depending on the combination of the metastable atom and the sample. The interpretation of this observation is that the scattered electron peak is enhanced when the energy of the metastable atom exceeds twice the band gap energy, i.e. when the electron—electron scattering of Penning electrons in the solid is feasible.     

BIOLOGICALLY EFFECTIVE DOSE OF SOLAR ULTRAVIOLET RADIATION ESTIMATED BY SPORE DOSIMETRY IN TOKYO SINCE 1980

Abstract— The biologically effective dose of solar UV radiation has been measured in Tokyo since 1980 using Bacillus subtills spores. To determine the cumulative dose in a half day, several samples of UV-sensitive spores were exposed in successive intervals from the solar-noon time. Because fluence-survival curves were exponential, the number of lethal hits received by the spores was calculated for each interval and termed inactivation dose (ID). The total number of hits obtained in a half day (half-day ID) was correlated with the amount of global insolation by a power-function regression. The regression analyses were performed for the data collected on 35 days from 1980 to 1986 and for the data collected on 53 days from 1989 to 1991. The latter data set yielded significantly larger estimates of half-day ID relative to the insolation than the former. These analyses suggested that the biologically effective dose relative to the insolation increased about 30% at some time in the later part of 1980s at this location. Changes of solar activity, air pollution and stratospheric ozone layer were considered as potentially responsible for this increase, but identification of the causative factors requires further efforts.     

Comparison of the relative intensities of penning electron spectrum and photoelectron spectrum. Unsaturaated hydrocarbons

The Ne* (³P₂) Penning electron spectra and the Ne I photoelectron spectra of ethylene, benzene, 1,3-butadiene, and styrene were compared. The π bands in the Penning spectra showed enhancement relative to the σ bands in comparison with the corresponding photoelectron spectra, suggesting that Penning electron spectroscopy has potential value for the assignment of photoelectron bands.     

Detection of chondroitin sulfate-binding proteins on the membrane

Chondroitin sulfate is a ubiquitous component of proteoglycans that is present both in the extracellular matrix and at the cell surface of various tissues. Until recently, chondroitin sulfate has attracted less attention than heparan sulfate and dermatan sulfate, owing to the limited number of known chondroitin sulfate-binding proteins. To determine the biological function of chondroitin sulfate, biotinylated probes were prepared and used to search for binding proteins. Chondroitin sulfates A, C, D, and E were biotinylated through either the uronic acid or the residual core peptide. Lysates from mouse Lewis lung carcinoma (3LL) cells were blotted onto a nitrocellulose membrane after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the membrane was treated with the biotinylated chondroitin sulfates. Among the chondroitin sulfate variants, the E type showed the most intense bands upon visualization of the membrane with avidin-conjugated alkaline phosphatase and the appropriate substrates. The binding of chondroitin sulfate E to proteins in the cell lysate was not affected by the A, C or D variants but was reduced by treatment with dermatan sulfate. Lysates from 3LL cells were also treated with biotinylated chondroitin sulfate E and, after two-dimensional (2-D) electrophoresis and blotting, several chondroitin sulfate E-binding proteins including lamins and heterogeneous nuclear ribonucleoproteins were identified by mass spectrometry.     

Construction of the multidecker anthracene-silver(I) system by intramolecular pi-pi interactions

As a continuation of the study on the construction of the multidecker aromatic compounds with pi-pi interactions, the anthracene derivatives 9,10-dimethylanthracene (dman), 9,10-diphenylanthracene (dpan), and 7,12-dimethylbenz[a]anthracene (dmban) have been studied toward complexation with the silver(I) ion. The crystal structures of [Ag(dman)(0.5)(p-xylene)(ClO(4))], [Ag(2)(dpan)(0.5)(C(6)H(6))(0.5)(CF(3)SO(3))(2)], and [Ag(2)(dmban)(2)(ClO(4))(2)](p-xylene), together with the metal-free ligand dpan, have been determined by single-crystal X-ray diffraction. These pi-electron-rich aromatic compounds are found to have great promise as an approach to the effective self-assembly of high nuclearity in a multilayer fashion.     

Syntheses and structures of photochromic silver(I) coordination polymers with cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethene

Five novel silver(I) coordination polymers with cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3- thienyl)ethene (cis-dbe) were synthesized and are characterized in this paper. Treatment of AgCF(3)SO(3) or AgCF(3)CO(2) with cis-dbe afforded [Ag(2)(cis-dbe)(CF(3)SO(3))(2)] (1) and [Ag(2)(cis-dbe)(CF(3)CO(2))(2)] (2), and both complexes exhibit a 1-D infinite chain structure with two cyano groups and two thienyl groups of the ligand bridging four metal ions. Reaction of AgC(n)()F(2)(n)(+1)CO(2) with cis-dbe gave rise to an unprecedented cocrystallization of a 2-D sheet structure, [Ag(2)(cis-dbe)(C(n)F(2)(n)(+1)CO(2))(2)], where n = 2 (3), 3 (4), and 4 (5). Upon irradiation with 450 nm light, these five silver(I) complexes turned orange or red from yellow, and the color reverted to yellow on exposure to 560 nm light, indicative of the reversible cyclization/ring-opening reaction occurring in the crystalline phase. Furthermore, different anions gave not only the different structural dimensions but also the different photoresponsive patterns. The correlation between the crystal structures and the photochromic reactivity is discussed.