Sound attenuation in one-dimensional magnetic systems at finite temperatures

Sound attenuattion constants are calculated for the one-dimensional ferro- and antiferromagnetic systems at finite temperatures. Their frequency dependences, in both cases, turn out to be $\text{ω}{}^{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}_{\mathrm{<mtext>k</mtext>}}\text{if}\text{ω}{}_{\mathrm{<mtext>k</mtext>}}\text{? ω}{}_{\mathrm{c}}\text{and}\text{ω}{}^2{}_{\mathrm{<mtext>k</mtext>}}\text{if}\text{ω}{}_{\mathrm{<mtext>k</mtext>}}\text{?ω}{}_{\mathrm{c}}$, where ω_c is a “cut-off” frequency related to the three-dimensional anisotropic interactions.     

POSSIBLE ROLE OF METALLOTHIONEIN IN THE CELLULAR DEFENSE MECHANISM AGAINST UVB IRRADIATION IN NEONATAL HUMAN SKIN FIBROBLASTS

Abstract: The role of metallothionein (MT) in protecting skin cells against UVB irradiation was investigated. Fibroblast strains from normal adult (HS-K) and neonatal (NB1RGB) human skins as well as keratinocyte strains from human skin (SV40-HSK) and newborn Balb/c mouse skin (Pam 212) were exposed to UVB irradiation.
The sensitivity of HS-K and NB1RGB cells to UVB irradiation was similar; those of SV40-HSK and Pam 212 cells were two- and six-fold as sensitive to UVB irradiation as HS-K cells, respectively. The HS-K cells contained the greatest cellular reduced form of glutathione (GSH) levels compared to the three other skin cells: the levels were 13-, 7- and 6-fold of those in NB1RGB, SV40-HSK and Pam 212 cells, respectively. These results indicated that the sensitivity of skin cells to UVB irradiation was not always associated with their endogenous GSH levels. In particular, despite the fact that NB1RGB cells contained a relatively small amount of GSH, they were less sensitive to UVB irradiation.
NB1RGB cells contained 4–30 times more MT than those in other skin cells examined. The sulfhydryl residues of MT molecules in the NB1RGB cells were estimated to be mostly unoccupied by metals, suggesting they act in a similar way to those of GSH. Moreover, NB1RGB cells in which the MT content was elevated by dexamethasone (1 μ M ) or Zn²⁺ (7 μg/mL) treatment were more resistant to UVB irradiation than nontreated ones.
These results suggest that, at least in neonatal human skin fibroblasts, MT may play a role in protection against UVB irradiation.     

Acoustic emission induced by tritium decay

An observation of signals of acoustic emission induced by tritium decay is reported. The equipment consisting of PZT detectors, preamplifiers, low-cut filters and computer evaluation was used in this study as a differential system. The result shows that the two types of clear signals of acoustic emission are induced by tritium decay. They seem to be related to some radiation effects due to tritium irradiation, and not to acoustic waves during tritium decay events.     

Formation of hot hexafluorobenzene in the 193 nm photolysis

Time-resolved absorption spectra of hexafluorobenzene vapor have been observed with ArF laser (193 nm) excitation. The initial intermediate is postulated to be due to HFB2(S₀) (hot hexafluorobenzene, with internal energy of 639 kj/mol) because the transient spectrum can be simulated as part of the S₃(¹E_1u) ← S₀ transition at 3050 K.     

Determination of perturbed angular correlation parameter\overline {G_{22} } for111In in hydrochloric acid solutions by the sum peak methodfor111In in hydrochloric acid solutions by the sum peak method

Application of the sum peak method to indium solutions in hydrochloric acid has been studied. A calibration line to determine a PAC parameter \(\overline {G_{22} } \) has been adopted using two samples with known values of \(\overline {G_{22} } \) . The results show feasibility of the method because of its simplicity and of smaller amounts of radioactivity required in the measurement compared to the ordinary PAC method.     

The local time of self-intersections of Brownian motions as generalized Brownian functionals

In this Letter, we show that the local time of self-intersections ofd-dimensional Brownian motions is a generalized Brownian functional in the sense of Hida.     

1-Phosphacephalosporin. I. Synthesis of racemic 7-unsubstituted-1-phosphadethia-3-cephem 1-oxides

The novel unnatural ring system, 1-phosphacephalosporin, was synthesized for the first time from 4-acetoxy-2-azetidinone.     

Efficient N-sulfenylation of 2-azetidinones using S-substituted thiophthalimides

Reaction of N-unsubstituted β-lactams with various S-substituted thiophthalimides provides an efficient route to the corresponding N-thio-2-azetidinones.