Photoacoust1C Studies on Very Thin Poly(Methyl Methacrylate) Films Prepared by a Cast1Ng-On-Water Method

Photoacoustic (PA) responses from very-thin poly(methyl methacrylate) (PMMA) films were investigated at various lamination conditions. The PA signal increased when the dye-doped films were laminated up to five layers, but tended to saturate beyond five layers. When the blank films were superimposed on the dye-doped film, the signal became smaller. The signal was larger when the dye-doped film was arranged outermost in the laminated film assembly of dye-doped and blank films. The results imply the effect of film vibration on the PA response.     

Roles of adriamycin and adriamycin dimer in antitumor activity of the polymeric micelle carrier system

Adriamycin (ADR) dimer was prepared and its antitumor activity was evaluated with mouse colon adenocarcinoma 26 (C 26). As compared with original ADR, the dimer did not show significant antitumor activity, either in vitro or in vivo. Furthermore, polymeric micelles containing varied ratios of the dimer to the original ADR were prepared. Polymeric micelles with a higher dimer/ADR ratio (9.7) showed significant antitumor activity, but the effective dose shifted higher. Effective doses were found to largely depend on the concentration of the original ADR, rather than that of the dimer at the tumor sites. Therefore, it was presumed that the original ADR played a major role in antitumor activity, and the dimer played a supplementary role to contribute selective delivery of ADR to the tumor sites.     

Far-infrared spectra of some β-hydroquinone clathrates

Far-infrared spectra (400-30 cm^?1) of Nujol mulls of the β-hydroquinone clathrates containing the following guest molecules were investigated: formic acid, formic acid-d₂, methanol, methanol-d₄, acetonitrile, acetonitrile-d₃, sulphur dioxide and also both of methanol and sulphur dioxide. The observed infrared bands of the mulls in the region of 4000-30 cm^?1 were classified into those due to the host lattice and those due to the guest molecules. On the basis of the comparison of the spectra, some bands were assigned to the translational or the rotational vibrations of guest molecules. Appearance of those bands suggested that some guest molecules are considerably bound in the cavities of the host lattice. Effect of temperature change on the bands was also measured.     

Application of intercalated compound of montmorillonite and N,N′-diphenyl-p-phenylenediamine to antioxidant for rubber materials

To extend the lifetime of rubber materials, the intercalated compound consisting of N, N-diphenyl-p-phenylenediamine (DPD) as guest molecule and montmorillonite as host layer was added to chloroprene rubber (CR) and acrylonitrile-butadiene rubber (NBR). These rubber samples were either immersed in a mixture of isooctane and toluene or kept at 140°C in air, and subjected to ozone aging tests. The residual DPD in CR was analysed by high pressure liquid chromatography. Their results were compared with the rubbers of a standard composition, including DPD alone. The solvent-immersed CR containing the intercalated compounds showed more improved ozone-cracking resistance than solvent immersed CR of the standard composition. The residual DPD in CR containing the intercalated compound was more than that in CR of standard composition. However, no significant difference between the specimens containing intercalated compound and those of the standard composition was observed for the solvent-immersed NBR, heat-treated NBR and heat-treated CR.     

Modification of interlayer space of kanemite with trimethylsilyl groups: structure and adsorption properties

Interlayer hydroxyl groups of layered silicate kanemite have been modified with trimethylsilyl groups by the reaction between the hydroxyl groups and trimethylchlorosilane. Expansion of the interlayer space by intercalation of dimethyldialkylammonium ions into the silicate layers enables the silylating reagent to access the hydroxyl groups. An increase in specific surface areas was observed with increasing concentration of trimethylsilyl groups. This result suggests that the interlayer space of kanemite can be used as an effective molecular adsorption space by weakening the interaction between the interlayer hydrogen bonds of hydroxyl groups. The modification of kanemite with trimethylsilyl groups restricted the adsorption of water below a monolayer capacity and was favorable for benzene adsorption.     

The first example of 2,2-dilithiocyanocyclopropanes: generation from 2-bromo-2-sulfinylcyanocyclopropanes with tert-butyllithium, property, and a synthesis of fully substituted cyanocyclopropanes

2,2-Dilithiocyanocyclopropanes were easily generated from 2-bromo-2-(p-tolylsulfinyl)cyanocyclopropanes with tert-butyllithium in toluene at −78 °C through concomitant sulfoxide-lithium and bromine-lithium exchange reactions. The gem-dianions were found to be stable at −78 °C for at least 30 min. Reaction of the gem-dianions with electrophiles gave fully substituted cyanocyclopropanes in moderate yields.     

Pyrimidine derivatives. VI. Synthesis of mono-, di-, tri-, and tetrabromo-substituted pyrimidine derivatives

The following bromo-2,4(1H,3H)-pyrimidinediones possessing a bromo substituent at the 5-position and side chains at the 1- and 6-positions were prepared. The three types of mono-bromo derivatives are: 1-(bromoalkyl)-3,6-dimethyl- 3a-d , 5-bromo-3,6-dimethyl-1-(hydroxyalkyl)- 4a-d , and 1-(acetoxyalkyl)-5-bromo-3,6-dimethyl-2,4(1H,3H)-pyrimidinediones 11a-d . The three types of dibromo derivatives are: 5-bromo-1-(bromoalkyl)-3,6-dimethyl- Sa-d , 1-(acetoxyalkyl)-5-bromo-6-bromomethyl- 8a, 8c , and 8d , and 5-bromo-6-bromomethyl 1-(hydroxyalkyl)-2,4(1H,3H)-pyrimidinediones 9a, 9c , and 9d . Likewise one group of tribromo and one group of tetrabromo derivatives are: 5-bromo-1-(bromoalkyl)-6-bromomethyl -7a-d and 5-bromo-1-(bromoalkyl)-6-dibromomethyl-2,4(1H,3H)-pyrimidinediones 6a-d .     

Production of D-lactic acid by bacterial fermentation of rice starch

D-Lactic acid was synthesized by the fermentation of rice starch using microorganisms. Two species: Lactobacillus delbrueckii and Sporolactobacillus inulinus were found to be active in producing D-lactic acid of high optical purity after an intensive screening test for D-lactic acid bacteria using glucose as substrate. Rice powder used as the starch source was hydrolyzed with a combination of enzymes: alpha-amylase, beta-amylase, and pullulanase to obtain rice saccharificate consisting of maltose as the main component. Its average gross yield was 82.5%. Of the discovered D-lactic acid bacteria, only Lactobacillus delbrueckii could ferment both maltose and the rice saccharificate. After optimizing the fermentation of the rice saccharificate using this bacterium, pilot scale fermentation was conducted to convert the rice saccharificate into D-lactic acid with a D-content higher than 97.5% in a yield of 70%. With this yield, the total yield of D-lactic acid from brown rice was estimated to be 47%, which is almost equal to the L-lactic acid yield from corn. The efficient synthesis of D-lactic acid can open a way to the large scale application of high-melting poly(lactic acid) that is a stereocomplex of poly(L-lactide) and poly(D-lactide). Schematic representation of the production of D-lactic acid starting from brown rice as described here.