Biomedical subjects

K Muroyama

Publications and source records attributed to K Muroyama.

4 recordsLinked to original sources

PubMed2005

Preparation and characterization of high-specific-surface-area activated carbons from K2CO3-treated waste polyurethane.

An activated carbon with high specific surface area was prepared from polyurethane foam by chemical activation with K2CO3 and the influences of carbonization temperature and impregnation ratio on the pore structure of the prepared activated carbon were investigated. It was found that the specific surface area of the activated carbon was at a maximum value (about 2800 m(2)/g) at a carbonization temperature of 1073 K and at an impregnation ratio of 1.0. It was concluded that the polyurethane foam structure was modified during impregnation by K2CO3, K2CO3 promoted charring during carbonization, and then the weight loss behavior was changed below 700 and above 1000 K, carbon in the char was consumed by K2CO3 reduction, and this led to the high specific surface area. The prepared activated carbon had a very sharp micropore size distribution, compared with the commercial activated carbon having high specific surface area. The amounts of three organic vapors (benzene, acetone, and octane) adsorbed on the prepared activated carbons was much larger than those on the traditional coconut shell AC and the same as those on the commercial activated carbon except for octane. We surmised that the high specific surface area was due to the modification of the carbonization behavior of polyurethane foam by K2CO3.

Journal Article↗

PubMed2001

Methane fermentation of bean curd refuse.

The methane fermentation of bean curd refuse was studied in a 1 l reactor with a draft tube which was operated in a fed-batch mode with a once-a-day feeding cycle using two kinds of methanogens. The effects of substrate loading rate on the methane yield and on the behaviors of the product species were examined. A unified approach was employed for the material balance between the substrate (reactant) and product species based on the elemental carbon content in the species being considered. The classified product species are methane and carbon dioxide in the gas phase, soluble TOCs excluding VFAs, ICs and VFAs in the liquid phase and cells, and the unconverted substrate in the solid phase. It is found that the methane yield increases with the increasing substrate loading rate, reaches a maximum and then decreases with a further increasing loading rate. The maximum methane yield is found to be as high as 53.7% which is very close to the theoretical yield of 55%. It is also found that there is a critical substrate loading rate beyond which the operation becomes impossible due to excessive accumulation of unconverted solids.

Journal Article↗

PubMed2000

Antitumor effect of heat-killed Lactobacillus plantarum L-137 through restoration of impaired interleukin-12 production in tumor-bearing mice.

We have previously reported that heat-killed Lactobacillus plantarum L-137 is a potent inducer of interleukin-12 (IL-12) in vivo as well as in vitro in mice. In order to develop effective usage of L. plantarum L-137 for tumor immunotherapy, we examined its antitumor effect against DBA/2 mice inoculated with syngenic P388D1 tumor cells in different treatment schedules. Daily injection of L. plantarum L-137 from the day of tumor inoculation induced a steep increase in plasma IL-12 only after the first injection but not after subsequent injections, and had no effect on tumor growth and survival time. In contrast, daily injection of L. plantarum L-137 from the 7th day after tumor inoculation exerted a marked antitumor effect but such an effect was not evident in mice treated with L. plantarum L-137 twice a week from the 7th day. IL-12 production was considerably impaired at the first injection but steeply increased after the third injection in the mice injected daily with L. plantarum L-137 from the 7th day. Our results suggest that daily administration of L. plantarum L-137 is required to exert an antitumor effect at the late stages of tumor development when IL-12 production is considerably impaired.

Adjuvants, Immunologic↗

PubMed1999

Immunopotentiating activity of nigerooligosaccharides for the T helper 1-like immune response in mice.

The immunopotentiating activity of nigerooligosaccharides (NOS), a mixture of nigerose, nigerosyl glucose and nigerosyl maltose, was studied in vitro and in vivo in mice. Mitogen-induced proliferation of splenocytes from normal mice was augmented in a dose-dependent manner by nigerose of NOS. NOS enhanced interleukin 12 (IL-12) and interferon-gamma (IFN-gamma) production by normal splenocytes in the presence of the potent IL-12 inducer, heat-killed Lactobacillus plantarum L-137, in vitro. Consistent with the in vitro finding, L. plantarum L-137-induced IL-12 production and IL-2-induced IFN-gamma production were augmented in mice fed with a 14.6% NOS diet for 2 weeks compared with mice fed with a control diet. Notably, mice fed with the NOS diet showed significantly longer survival time than the control mice after the induction of an endogenous infection by administering 5-fluorouracil in a lethal dose. Taken together, these results suggest that NOS may exert immunopotentiating activity through the activation of an IL-12-dependent T helper 1-like immune response.

Animals↗