On the Casson invariant of homology 3-spheres of Mazur type

We compute the Casson invariant for some integral homology 3-spheres. We also show that for every integer n, there exists an integral homology 3-sphere of Mazur type with the Casson invariant 2n.     

Species and organ differences of sulphate conjugation of p-nitrophenol in liver and platelets.

Sulphate conjugation of p-nitrophenol (p-NP) in the liver and platelet cytosol of guinea pigs, rabbits and dogs were studied. The dependency of phenol sulphotransferase (PST) activity on p-NP concentration in the liver of guinea pigs and rabbits and in the platelets of guinea pigs were similar to that reported for the liver (Mizuma et al., J. Pharmacobio-Dyn., 6, 851 (1983)) and platelets (Nakamura et al., J. Pharm. Pharmacol., 42, 207 (1990)) of rats. There was one peak of PST activity on p-NP at the concentration of 1 to 10 microM, and the PST activity was increased again with an increase of p-NP concentration above the original concentration. On the other hand, a peak in PST activity on p-NP at the concentration of 1 to 10 microM was not observed in the platelets of rabbits and dogs. These results indicated species and organ differences in PST activity on p-NP in liver and platelets. The biphasic activities of the PST and p-NP in platelets and liver of rat and guinea pig were similar to that reported in humans (Reiter et al., Naunyn-Schmiedeberg's Arch. Pharmacol., 324, 140 (1983)).     

LASER PHOTOLYSIS STUDY ON POLY(N-VINYLCARBAZOLE) ADSORBED ON CELLULOSE SUBSTRATE

Abstract Triplet state and photoinduced charge separation dynamics under adsorption was Confirmed for the first time for the polymer without or with coadsorbed electron acceptor, respectively. The absorption spectrum of the triplet polymer is similar to the T_n← T₁ band of N -ethylcarbazole, showing no appreciable interchromophoric interaction. Absorption spectra of the coadsorbed systems comprise the polymer cation and electron acceptor anion. The ion radicals on the cellulose substrate undergo mutual recombination, and simple uni- and bimolecular decay kinetics do not hold. This mechanism was compared with that for poly( N -vinylcarbazole) film.     

Synthesis of poly(lactide‐ran‐MOHEL) and its biodegradation with proteinase K

Homopoly(L ‐lactide) and homopoly(D,L ‐lactide) were almost inert for biodegradation with tricine buffer or normal enzymes such as bromelain, pronase, and cholesterol esterase but biodegradable with proteinase K. Significantly enhanced biodegradation was observed when an optically active (R)‐ or (S)‐3‐methyl‐4‐oxa‐6‐hexanolide (MOHEL) unit was introduced into poly(L ‐lactide) [poly(L ‐LA)] or poly(D,L ‐lactide) [poly(D,L ‐LA)] sequences. Poly[L ‐LA‐ran‐(R)‐MOHEL] in molar ratios of 86/14 to 43/57 showed good biodegradability that was independent of crystallinity. The biodegradation of polymers with proteinase K increased in the following order: poly[D,L ‐LA‐ran‐(R)‐MOHEL] > poly[L ‐LA‐ran‐(R)‐MOHEL] > poly[D,L ‐LA‐ran‐(S)‐MOHEL] > poly[L ‐LA‐ran‐(S)‐MOHEL] > poly(R)‐MOHEL > poly(D,L ‐LA). The number‐average molecular weight, molecular weight distribution, glass‐transition temperature, and melting temperature did not change before and after the biodegradation of poly[L ‐LA‐ran‐(R)‐MOHEL], indicating that the degradation occurred from the polymer surface. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1374–1381, 2001     

Specific oxygen-binding to a polymer-supported N,N-disalicylidenethylenediaminocobalt complex

A polymer membrane containing N,N-disalicylidenethylenediaminocobalt (Co(salen)) was prepared. The Co(salen) supported in the polymer not only worked as a reversible and specific oxygen-adsorbent but discontinuously bound oxygen at the atmospheric oxygen partial pressure of ca. 15 cmHg to give an on-off-like oxygen-binding curve. Oxygen permeation through the Co(salen) membrane was also augmented in the higher upstream oxygen pressure region, which was caused by the specific oxygen-binding to the Co(salen) fixed in the membrane.