Vectorial finite-element method without spurious solutions for dielectric waveguide problems

A new vectorial finite-element method for the analysis of dielectric waveguide problems is formulated in terms of all three components of the magnetic field H. In this approach, the relation div H = 0 is satisfied and the spurious non-physical solutions do not appear.     

An 18-ns 1-Mbit CMOS SRAM

A 1-Mb (256 K×4 b) CMOS static random-access memory with a high-resistivity load cell was developed with 0.7-μm CMOS process technology. This SRAM achieved a high-speed access of 18 ns. The SRAM uses a three-phase back-bias generator, a bus level-equalizing circuit and a four-stage sense amplifier. A small 4.8×8.5-μm² cell was realized by the use of a triple-polysilicon structure. The grounded second-polysilicon layer increases cell capacitance and suppresses α-particle-induced soft errors. The chip size measures 7.5×12 mm²     

Autonomic nervous system dysfunction in elderly hypertensive patients with abnormal diurnal blood pressure variation: relation to silent cerebrovascular disease

To investigate the relationships among diurnal blood pressure (BP) variations and autonomic nervous system dysfunction, we assessed heart rate variability (HRV) using power spectral analysis of the 24-hour RR interval in 51 asymptomatic elderly hypertensive patients with various patterns of nocturnal BP fall. The extreme-dippers with marked nocturnal BP fall (n=16) had lower asleep low-frequency power (LF)/high-frequency power (HF) ratios (a relative index of sympathetic nervous system activity), while the nondippers without nocturnal BP fall (n=18) had lower awake LF/HF ratios and asleep/awake ratio for HF (an index of parasympathetic nervous activity), when compared with dippers with appropriate nocturnal BP fall (n=17). The incidence of multiple lacunar infarction detected by brain magnetic resonance imaging was 56% in the extreme-dippers and 38% in the nondippers, and both were markedly higher than that (6.3%) in the dippers (both P<.01). There was no significant relationship between the BP level and any HRV parameter for either the daytime or nighttime period. The asleep/awake ratio for systolic BP was significantly correlated with the asleep/awake ratio for HF (r= -.363, P<.01) and with the asleep/awake ratio for the LF/HF ratio (r=.540, P<.001), regardless of whether multiple lacunar infarction was present. In conclusion, the autonomic nervous system activity is not related to high BP level per se, rather its diurnal variation is more important as a determinant of the diurnal BP patterns, regardless of the presence or absence of cerebrovascular disease.     

Surgical experience in patients with Marfan's syndrome and cardiovascular disease

10 patients with Marfan's syndrome and cardiovascular disease were operated at Tohoku University Hospital from 1971 to 1988. Surgery included composite valve graft replacement of ascending aortic aneurysm with aortic regurgitation in 5 patients and prosthetic mitral valve replacement in three patients; two had resection of aneurysm with Dacron tube replacement. Operative mortality was 10%. Two late death occurred (22%). It was suggested that regular follow-up examination is important in these patients to detect new lesions and to evaluate known lesion.     

Development of thick wall 2.25Cr-1MoNiNb steel forgings for steam generators of fast breeder reactors

The large and thick forgings made of 2.25Cr-1MoNiNb steel are required for vessel material of steam generator (SG) of the fast breeder reactor SNR 300.In order to study the feasibility of 2.25Cr-1MoNiNb steel heavy section forging, chemical composition, melting practice and ingot making, hot working and heat treatment conditions were investigated. The following recommendations were derived: (1) 0.04% C, 0.10% ΔNb, (2) application of electro-slag remelting process, (3) grain refining by hot working, (4) two-step austenitizing at 1020°C.Based on these recommendations, the actual products such as hollow cylinders with maximum 290 mm thickness, solid bars with 420 mm diameter and forged plates with maximum 185 mm thickness could be supplied for application in the helical coiled SG of the SNR 300. Statistical analysis of the products showed the sufficient and isotropic material properties, which fulfill the requirements of the basic safety rules.     

A possible mechanism for hyperthermic radiosensitization mediated through hyperthermic lability of Ku subunits in DNA-dependent protein kinase

DNA-dependent protein kinase (DNA-PK), composed of p470 catalytic subunit and p85/p70 heterodimer of Ku autoantigen, is considered a critical enzyme in DNA double-strand break repair. We purified DNA-PK from human leukaemic MOLT-4 cells by successive column chromatography and separated into p470 and Ku subunits by ultracentrifugation in glycerol gradient. We studied hyperthermic stability of DNA-PK holoenzyme and its separated subunits to test a possible role of DNA-PK in hyperthermic radiosensitization. DNA-PK was found to lose its activity rapidly at hyperthermic 44 degrees C, and further, Ku subunits instead of p470 catalytic subunits were found to be sensitive to hyperthermia. These results indicate a possibility that hyperthermic radiosensitization is mediated through the heat lability of Ku subunits of DNA-PK, impairing repair of radiation-induced double-strand break of DNA.