SynopsisDynamic recrystallization behavior of austenite in 1%/b-bearing HSLA steels as well as 18--8 stainless steel was investigated by hot compression testing. The hot deformation equipment, incorporating a rapid cooling system and an on-line data analysis system, made it possible to investigate the microstructural changes associated with the restoration process by fully suppressing the static recovery and recrystallization. The stress-strain behavior to a strain of 0.70 was investigated in the range of strain rate from 5 x 10-4 to 10 and of temperature from 900 to 1200 °C. Dynamic recrystallization was observed in all the steels deformed under the condition of the Zener-Hollomon parameter being less than 1015 s-1, but it was not observed with the highest strain rate of 10 s-1. An increase of JVb content in the HSLA steels increased the flow stress for any deformation condition and also increased the strain at onset of dynamic recrystallization. Dynamically recrystallized grain size was primarily related to the value of the Zener-Hollomon parameter, but was not influenced by the initial grain size. The microstructural changes accompanying dynamic recovery and dynamic recrystallization were investigated by thin foil TEM observation and related to the results of hardness measurements.

Blue-green alga, Nostoc commune is rich in dietary fiber. To examine the hypocholesterolemic effect, the alga or the dietary fibers were given to the rats fed cholesterol diet. Serum cholesterol elevation was significantly depressed in those rats. Cholesterol increased in the liver of rats given the alga and the fiber. The content of fecal cholesterol and bile acid unchanged. Of the dietary fibers, oxalate-oxalic acid soluble substance (OOSS) found abundant in the alga was most effective in lowering cholesterol in the serum. It seems to depress the elevation of LDL-cholesterol. The mechanism of hypocholesterolemic effect by OOSS remains to be unclear. This study indicated that Nostoc commune is expected to be a new dietary fiber source of possible importance in human nutrition.

SummaryThe significant antihypercholesterolemic effect of the un digested high molecular fraction (HMF) of soybean protein is known in rats, but such an effect has not been shown in humans. The present two experiments were designed to elucidate it in humans. Subjects were female university students who had relatively high serum cholesterol levels for their age. In Experiment 1, subjects took 8% of their total energy from casein, soybean protein isolate (SPI), or HMF daily for 14 days. Five basic menus and snacks were cycled. Energy intakes and daily activities were kept constant and body weight was maintained. The HMF group showed decreased low-density lipoprotein cholesterol (LDL-C) as compared to other groups. In Experiment 2, subjects took 4% of total energy from casein or HMF daily for a menstruation period . Five basic menus and snacks which contained two egg yolks (about 500 mg choles terol) were cycled. Energy intakes and daily activities were kept constant and body weight was maintained. A decrease in LDL-C and an increase in high-density lipoprotein cholesterol (HDL-C) were observed in the HMF group as compared to the casein group. Fecal acidic steroid excretion was greater in the HMF group than in the casein group (p< 0.05). The results confirmed that HMF increases fecal steroid excretion and reduces serum cholesterol levels in humans.