Fabrication of dense β-calcium orthophosphate with submicrometer-sized grains and its high-temperature superplastic deformation

High-density β-calcium orthophosphate (β-Ca₃(PO₄)₂, also called β-tricalcium phosphate: β-TCP) ceramics with submicrometer-sized grains were fabricated using a pulse-current pressure firing route. The maximum relative density of the β-TCP compacts was 98.7% at 1050 °C and this was accompanied by a translucent appearance. The mean grain size of the β-TCP compacts increased slightly with temperature to reach 0.78 μm at 1000 °C. However, upon further increasing the firing temperature to 1050 °C the mean grain size increased significantly to 1.6 μm. The extent of plastic deformation during tensile testing was examined at temperatures between 900 and 1100 °C using a strain rate in the range 9.26 × 10⁻⁵ to 4.44 × 10⁻⁴ s⁻¹. The maximum tensile strain achieved was 145% for a test temperature of 1000 °C and strain rate of 1.48 × 10⁻⁴ s⁻¹ and this was attributed to the relatively high density and small grain size.     

Heavy-ion-induced luminescence of amorphous SiO2 during nanoparticle formation

Silica glass was implanted with negative 60 keV Cu ions at an ion flux from 5 to 75 μA/cm² up to a fluence of 1 × 10¹⁷ ions/cm² at initial sample temperatures of 300, 573 and 773 K. Spectra of ion-induced photon emission (IIPE) were collected in situ in the range from 250 to 850 nm. Optical absorption spectra of implanted specimens were ex situ measured in the range from 190 to 2500 nm.

IIPE spectra showed a broad band centered around 560 nm (2.2 eV) that was assigned to Cu⁺ solutes. The band appeared at the onset of irradiation, increased in intensity up to a fluence of about 5 × 10¹⁵ ions/cm² and then gradually decreased indicating three stage of the ion beam synthesis of nanoclusters: accumulation of implants, nucleation and growth nanoclusters. The IIPE intensity normalized on the ion flux is independent on the ion flux below 20 μA/cm²at higher fluences. The intensity of the band increased with increasing samples temperature, when optical absorption spectra reveal the increase of Cu nanoparticles size.     

The effects of an angiotensin-converting inhibitor (enalapril) on patients with mild cardiac failure--evaluating cardiac function based on the relationship between daily walking pace and heart rate

BACKGROUND: Heart failure has been evaluated by several methods, the New York Heart Association (NYHA) classification of heart failure based on symptoms being used most frequently. However, the degree of heart failure assessed by these criteria does not always correlate with cardiac function in daily life. HYPOTHESIS: The aim of the study was to evaluate cardiac function based on the walking pace/heart rate (HR) relationship to assess the effects of enalapril, an angiotensin-converting enzyme inhibitor, in patients with mild to moderate cardiac function. METHODS: To evaluate cardiac function objectively, we developed a method using a pedometer to count the steps walked while simultaneously recording HR using a Holter electrocardiograph (ECG). Step-count walk rate (WR) was recorded on the magnetic tape of the Holter apparatus, and both HR and walking pace were calculated automatically by the Holter ECG analysis system. Data were determined every hour, and mean pace and HR were plotted along the x and y axes, respectively. The slope of HR x WR was calculated using the least squares method. The slope and the total number of steps were regarded as indicators of cardiac function and quality of life, respectively. We analyzed 36 subjects, consisting of 8 normal volunteers, 8 patients in New York Heart Association (NYHA) class I. 11 in class II, and 9 in class III chronic mild heart failure, during maximal exercise work load by bicycle ergometer; furthermore, fractional shortening of the left ventricle on echocardiogram was determined in 14 patients with chronic mild heart failure and was compared with the slope of HR x WR. Enalapril was administered at a daily dose of 2.5-10 mg for 1-24 months (mean 6 months) in 60 patients to evaluate the effects of this drug on these parameters. RESULTS: There was a significant inverse relationship between maximal work load and the HR x WR slope, and also between the fractional shortening and the slope, suggesting that the slope may reflect the severity of cardiac dysfunction. Furthermore, the slope decreased significantly from 1.8 +/- 1.26 before enalapril to 1.0 +/- 0.94 (mean +/- standard deviation) after drug administration, while the total number of steps increased significantly from 4842 +/- 3581 to 7804 +/- 4793. CONCLUSION: The slope of the graph relating step count and HR proved to be a good, objective indicator of cardiac function, and enalapril therapy improved this parameter.     

Diagnosis method for live-wire insulation of high-voltage XLPE cables by DC superimposition

Recent preventive maintenance for equipment has grown to include diagnosis of the insulation of cables under hot-line conduction. Much of the equipment constructed during the high-growth period in the 1960s has become obsolete. Recent circumstances make it difficult to obtain a longer service interruption time. Results of a study of the method that measures the live-wire insulation resistance by superimposing dc 50 V to a high-voltage busbar through GPT and forms a bridge with the resistance of a cable insulation are discussed. It is clarified that this live-wire insulation diagnostic method is highly effective at detecting degradation of a cable insulation resistance and is, therefore, suitable for so-called trend monitoring as well.     

Theory and clinical application of functional MRI: 3D-functional brain mapping

Functional magnetic resonance imaging (fMRI) was performed using a clinical 1.5 T MR scanner. Normal volunteers and patients with several neurological disorders were studied with somatosensory stimulation using sponge at right hand and visual stimulation using checkerboard pattern. Both fMR images by gradient echo echo planar imaging and three dimensional gradient echo images were studied. Reconstructed 3 dimensional functional brain mapping was superimposed on 3D anatomical images. Apparent signal increase was observed at contra lateral sensorimotor cortex and secondary sensory cortex with sponge stimulation. In the case of left homonymous hemianopia due to cerebral infarction, increasing signal was only observed surrounding left calcarine fissure by using stimulation of all visual field. In conclusion, fMRI and 3-D functional brain mapping has extremely high potentiality to examine pathophysiology of various neurological disorders.     

Bone lesion in multiple myeloma--bone mineral density measured by dual energy X-ray absorptiometry in multiple myeloma]

The paper discusses some of the factors that affect the onset of osteoporosis, and provides an original model for rehabilitation procedure in this disorder. The type of motor exercises used are indicated, and the sequence in which they are done. There is also a discussion of the significance of the application of physiotherapy equipment. Attention is also drawn in the paper to the possibility of the patient applying rehabilitation procedures independently, under only periodic supervision by the physician.     

Process synthesis by task assignment

An approach by task assignment is presented to determine processing system structures in chemical process design. For given design conditions of major subsystems, which were specified by the results of basic or applied research, a basic flowsheet is determined by task assignments on energy recovery and material flow transportation. An illustrative example shows the usefulness of the present method.