Single-dose four hour dexamethasone suppression test in normal men and its application for the diagnosis of Cushing's syndrome

As a four hour morning test, plasma cortisol levels were radioimmunoassayed before and at two and four hours after dexamethasone (0, 0.5 mg, 1.0 mg or 2.0 mg) was administered at 8-9 a.m. in 20 normal subjects. The 1.0 mg four hour test was most effective in suppression of cortisol and it showed the same suppressibility as the widely used single-dose overnight test. With the 1.0 mg four hour test, 2 patients with Cushing's syndrome due to adrenal hyperplasia could be differentiated from normal and obese subjects. The four hour morning test would be more useful than the widely used overnight test from the reasons; i) it shows the same suppressibility as the overnight test, ii) it obviates the need for bothersome midnight administration of dexamethasone, iii) because it takes only one morning to perform, it can save a day, iv) and it might be applicable for the differential diagnosis of Cushing's syndrome because 4.0 mg morning test resulted in complete suppression of plasma cortisol in a tested Cushing's syndrome, whereas with even 8.0 mg, plasma cortisol was not suppressed in the overnight test in 2 such patients examined.     

Application of Homomorphic Deconvolution to Dilution Curves

The application of a homomorphic deconvolution technique to indicator dilution curves is investigated. An indicator dilution curve with recirculation is decomposed into the primary circulation and the first recirculation components by homomorphic filtering. First, the method is applied to a simple model in which a dilution curve with recirculation is represented by mathematical functions. The assumed mean transit time and shunt fraction are determined from the two decomposed curves. Second, the method is applied to real data, i.e., the pulmonary time-activity curves from radionuclide angiocardiography. Pulmonary-to-systemic flow ratios are calculated from the areas of two decomposed curves and compaxed with those from cardiac catheterization. It may be concluded that homomorphic deconvolution seems to be a possible method of recovery of the primary circulation curve and also of the first recirculation curve from an indicator dilution curve with recirculation.     

Grain-Boundary Microcracking Due to Thermal Expansion Anisotropy in Aluminum Titanate Ceramics

The relation between grain size and grain-boundary microcracking during cooling in aluminum titanate ceramics was studied. Microcracking temperature was determined by the measurement of thermal contraction and expansion, which was accompanied by acoustic emission. When the ceramics were cooled at a rate of 6°C/min, stress relaxation did not occur below the sintering temperature of 1500°C. The relation between the temperature difference from the sintering temperature to the microcracking temperature and the grain size showed good agreement with the prediction based on the energy criterion of grain-boundary microcracking.     

Computer architecture for intelligent robots

This article proposes a computer architecture suitable for intelligent robots, especially for self-contained intelligent mobile robots. The main principles proposed by the authors are: (1) The robot should be a multiprocessor system with a master, several slave modules and a console. A simple star connection is employed. (2) The master carries user's programs written in a high level language with which a programmer is able to use all basic functions in the robots. It should have a special purpose operating system. (3) Each module is an independent microcomputer system loosely coupled to the master and dedicated to an elementary function such as manipulation, locomotion, sensing, or planning. (4) A serial TTL level or RS232C interface is employed between the master and each module. Two self-contained robots, Yamabico 9 and 10, constructed under these design principles have demonstrated the effectiveness of this proposed architecture.     

Microstructural evolution and its effect on Hall-Petch relationship in friction stir welding of thixomolded Mg alloy AZ91D

Microstructural evolution of a thixomolded magnesium (Mg) alloy AZ91D during friction stir welding was investigated. Friction stir welding resulted in a homogeneous microstructure consisting of fine recrystallised -Mg grains in the thixomolded material. The microstructural homogenisation and refinement was attributed to dynamic recrystallisation accompanied by the dissolution of the eutectic structure during the welding. The grain refinement in the stir zone was effective in increasing the hardness, as predicted by the Hall-Petch equation. The effect of grain size on hardness was smaller than that in conventional and rapidly solidified AZ91. This phenomenon may be explained as being due to the microstructure of the stir zone which consisted of fine equiaxed grains with a high density of dislocations.     

BWR core-wide stability analysis with respect to dominant feedback mechanisms and characteristic poles

BWR core-wide stability is studied from the viewpoint of linear dynamic stability treated via poles of a closed-loop transfer function. The quantitative study is performed using a BWR noise model describing neutronic and thermal-hydraulic core dynamics. Transfer functions of neutron power to reactivity and core inlet flow are derived in explicit forms and their poles are evaluated both numerically and analytically. It is shown that the characteristic poles may be classed into three groups relating to neutronic process, fuel heat transfer and core void dynamics. In particular, the poles for the void dynamics take complex values and hence give rise to core-wide damped oscillation of neutron power. Furthermore, the study of characteristic poles serves for the stability analysis of the Ringhals-1 benchmark test data. It is shown and clarified that two stability indexes, decay ratio and resonance frequency, have clear dependence on reactor power and core inlet flow.     

POLYPHONET: An advanced social network extraction system from the Web

Social networks play important roles in the Semantic Web: knowledge management, information retrieval, ubiquitous computing, and so on. We propose a social network extraction system called POLYPHONET, which employs several advanced techniques to extract relations of persons, to detect groups of persons, and to obtain keywords for a person. Search engines, especially Google, are used to measure co-occurrence of information and obtain Web documents.

Several studies have used search engines to extract social networks from the Web, but our research advances the following points: first, we reduce the related methods into simple pseudocodes using Google so that we can build up integrated systems. Second, we develop several new algorithms for social network mining such as those to classify relations into categories, to make extraction scalable, and to obtain and utilize person-to-word relations. Third, every module is implemented in POLYPHONET, which has been used at four academic conferences, each with more than 500 participants. We overview that system. Finally, a novel architecture called Iterative Social Network Mining is proposed. It utilizes simple modules using Google and is characterized by scalability and relate–identify processes: identification of each entity and extraction of relations are repeated to obtain a more precise social network.