Silicon nitride with anisotropic microstructure was fabricated by tape-casting of raw powder slurries with 0-10vol% seed particles of morphologically regulated β-Si3N4 single crystal, followed by gas ...pressure sintering of stacked sheets. The effect of orientation degree and area fraction of large elongated grains on mechanical properties was studied. Fracture toughness (KIC) and bending strength (σf) measured in the direction perpendicular to grain alignment increased with an increase in seeds amount, which was associated with the fact that both orientation degree and area fraction of large elongated grains increased with increasing amount of seeds. The specimen with 5vol% seeds, in which large elongated grains occupy a cross-sectional area of about 46%, exhibited a dominant orientation parallel to the casting direction. The specimen showed high KIC of 11.7MPa·m1/2 and high σf of 1200MPa. Further addition of seeds resulted in a slight decrease in KIC and σf owing to pore generation and coalescense of large elongated grains. On the contrray, KIC and σf measured in the direction parallel to the grain alignment decreased monotonously with an increase in seeds amount.
To evaluate the usefulness of total androgen blockade (TAB) therapy, we retrospectively studied 45 patients with prostate cancer who received TAB therapy as the first-line treatment. The clinical ...stage was A2 in 1 patient, B1 in 10, B2 in 9, C in 6, D1 in 3 and D2 in 16. Seven, 25 and 13 patients had well, moderately and poorly differentiated adenocarcinomas, respectively. The patients were placed on 1 of 3 TAB regimens: Luteinizing hormone-releasing hormone (LH-RH) agonist and flutamide (group 1), LH-RH agonist and chlormadinone acetate (group 2) and a surgical castration and flutamide (or chlormadinone acetate) (group 3). The therapeutic effect was evaluated at 12 weeks according to the response criteria in the general rules for clinical and pathological studies on prostatic cancer. The overall response was partial response (PR) in 35 patients (77.8%), no change (NC) in 6 (13.3%) and progressive disease (PD) in 4 (8.9%). PR was obtained in 81.3, 79.2 and 60% of the patients in groups 1, 2 and 3, respectively. One patient with PD responded briefly to flutamide withdrawal. None of the patients developed any severe adverse effects. In conclusion, the first-line TAB therapy is effective for prostate cancer with a lower risk than estrogens. Relapsed cases should be followed for flutamide withdrawal syndrome during TAB therapy.
Silicon nitride with unidirectionally oriented elongated grains was fabricated by the combination of seeding and extrusion process. Development of such highly anisotropic microstructure is due to the ...high shear stress exerted during the extrusion process, which allowed the unidirectional alignment of rod-like seed particles. Small matrix grains were almost consumed by selective grain growth into larger grains grown from seed particles, consequently, large elongated grains with high aspect ratio were dominant in the microstructure of this material. Such microstructure development is related to the fact that the unidirectional alignment of seeds along a precise direction inhibits mutual impingement of elongated grains during growth along their length direction. Both high strength of about 1.4GPa and high fracture toughness of about 14MPa·m1/2 could be achieved by testing in the direction parallel to grain alignment.
To investigate the effect of microwave heating on grain growth behavior in silicon nitride ceramics, microwave annealing was carried out using a microwave radiation frequency of 28GHz. A comparative ...study of silicon nitride annealed by microwave and by conventional heating was done using scanning elec tron microscopy (SEM) observation and image analysis. Results show that microwave annealing is more effective in enhancing the grain growth and in producing the bi-modal microstructure than conventional heating. In particular, the growth along the c-axis was more remarkable due to the local and selective heating of the liquid phase by the microwave.
Eleven years follow up observation has been done in an adult patient with glycogen storage disease type 1 with special reference to the serum uric acid. In 1969 at the first visit to our hospital, he ...was 20 years old and his serum uric acid was 13.5 mg/dl. Serum uric acid was controlled under 8 mg/dl by administration of benzbromarone or allopurinol. As he felt well he stopped to take any drug since December 1971. Nevertheless his serum uric acid remained at 9.8mg/dl in January 1977 and it was rather lowered to 7.7 mg/dl in October 1980. Laboratory data in 1969 and 1980 showed that lipid metabolism was improved but glucose was not. Although the real reason is not clear, the partial deficiency of enzyme, or an adaptation of metabolism was considered for the spontaneous improvement of uric acid metabolism in this case.
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