Chance discovery in medicine — Detection of rare risky events in chronic diseases —

One of the most important characteristics of chance discovery is that it focuses on the specific events or patterns in which the essential nature of an applied domain is implicitly included. The understanding and forecasting of such patterns and events will have a significant impact on decision making in the applied domain. This paper discusses the meaning of chance discovery from the viewpoint of medicine. Since chance discovery in medicine can be viewed as the way to find a suitable occasion for some critical actions or to check the dangerous possibilities, called rare risky events, detection and interpretation of rare but important events are ones of the components that supports chance discovery. According to this observation, several approaches for detecting rare events were introduced and evaluated by a small dataset on neurological diseases. Experimental results show that a set of events which include rare risky events can be detected by the introduced detection method, though interpretation by domain experts is required for selection of such events. Shusaku Tsumoto, Ph.D.: He graduated from Osaka University, School of Medicine in 1989. After residents of neurology in Chiba University Hospital, he was involved in developing hospital information system in Chiba University Hospital. He moved to Tokyo Medical University in 1993 and started his research on rough sets and data mining in medicine. He received his Ph.D (Computer Science) from Tokyo Institute of Technology in 1997, and is now a Professor at Department of Medical Informatics, Shimane Medical University. His interests include approximate reasoning, data mining, fuzzy sets, knowledge acquisition, mathematical theory of data mining, and rough sets (alphabetical order).     

Development of a composite boring bar

A composite boring bar, whose stability against chattering is superior to not only conventional steel bars but also cemented carbide bars, has recently been developed. The main material of this composite bar is pitch-based carbon fiber reinforced plastic. Carbon fibers aligned unidirectionally in the longitudinal direction of the bars give high bending stiffness. Four types of bar having different shaped steel cores were designed by FEM analysis and produced for actual testing. A bar having a cross-shaped steel core shows the best cutting capability and stability amongst all bars designed. This bar can be used when the length (L) and diameter (D) ratio L/D is 7 or even at severe conditions while a cemented carbide bar cannot control the chatter vibration even if the L/D is less than 6. Emphasis should be placed on the fact that the cross-shaped steel core can increase the bending stiffness of the bar in both tangential and radial directions by constraining the shear deformation of the fiber layers without sacrificing the increase of resonant frequencies.     

Superplasticity of mullite-zirconia composite

Tension tests of mullite-zirconia composite were conducted at elevated temperature. A superplastic elongation of 122% could be achieved at an initial strain rate of 2.86×10^–5s^–1 at 1550°C. Strain hardening was observed at strain rates from 1.42×10^–4 to 2.86×10^s–5s^–1 at 1550°C. The addition of zirconia grains to the mullite matrix increased the creep rate of the composite.     

Comparison of measured and predicted field strengths of medium frequency sky waves over short distances in Japan

Nighttime sky waves of four medium frequencies were observed at distances of not larger than about 300 km in Japan for one to two years of high and low solar activities. The sporadic E (Es) layer always appeared with high probability. Analyzing these data, the following results were obtained: 1) the measured median field strengths are different by at least more than 7 dB from full wave predicted values for the international reference ionosphere (IRI) without the Es-layer. But these agree fairly well with the full wave calculation for IRI with the Es-layer, 2) the field strength approximates the Rayleigh distribution, 3) according to the data for high solar activity, the sky wave appears rapidly after sunset, and during the two to six hours after sunset all median field strengths are about constant.     

Endoscopic appearances of hemorrhagic peptic ulcers and efficacy of H2-receptor antagonists

BACKGROUND/AIMS: In this retrospective study, we compared the effects of histamine H2-receptor antagonists to those of antacids and anticholinergics in patients with hemorrhagic ulcers with various endoscopic appearances of bleeding. PATIENTS AND METHODS: Patients with hemorrhagic ulcers (n = 376) were examined by emergency endoscopy and were treated with 1) antacids and anticholinergic drugs or 2) H2-receptor antagonists. RESULTS: In ulcer patients with oozing or fresh red coagulation, H2-receptor antagonists ceased further hemorrhage more effectively (65.9% of the cases) than antacids and anticholinergic drugs (46.7%). In patients with projectile bleeding, both of the treatments failed to stop hemorrhage. There were no significant differences in favorable outcome in the patients only with old black coagulation between antacid and anticholinergic drugs-treated group and H2-receptor antagonists-treated group (94.4% and 93.8%, respectively). CONCLUSIONS: The results suggest that H2-receptor antagonists are more effective than antacids and anticholinergic drugs in patents with peptic ulcer with fresh coagulation or oozing, but not with projectile bleeding or old black coagulation. The results also indicate that endoscopic appearances of peptic ulcer bleeding are good predictors for the effects of medication.     

Measurement of absolute intensity of weak magnetic fields using rf biased SQUID

A method to measure the absolute intensity of a weak magnetic field is described. We used a superconducting material as a sensor and detected its magnetization change between the superconducting state and the normal state at the transition temperature. The magnetization change measured by the SQUID system is proportional to the component of the absolute intensity of the magnetic field at the superconductor specimen which in parallel with the axis of the astatic pick up coils. A resolution as good as 10^?5 Oe has been obtained. The practical limit of the resolution of this method is also discussed.     

Development of a time-resolved fluorometric detection system using diffusion-enhanced energy transfer

A novel detection system using both emission energy transfer and time-resolved fluorometry (TRF) was developed, with a europium chelate as the energy donor and a novel fluorophore SNR1, excitable with long-wavelength light corresponding to europium emission, as the energy acceptor. When the donor and acceptor molecules were mixed in solution, energy transfer was observed without direct attachment of the donor and the acceptor, via a diffusion-enhanced energy-transfer mechanism. Thus, the acceptor emission can be detected as a long-lifetime fluorescence in TRF. When the fluorescence properties of the acceptor molecule are changed by interaction with an enzyme or other bioactive molecule, the change can be detected as a long-lived sensitized emission. If we develop or select suitable acceptor molecules, this simple and convenient system should be applicable to a wide variety of bioactive molecules. Since it is based on TRF, it can be used for high-resolution assay.     

A review and evaluation on constructive heuristics to optimise product mix based on the Theory of Constraints

In this paper, we address the problem of defining the product mix in order to maximise a system's throughput. This problem is well known for being NP-Complete and therefore, most contributions to the topic focus on developing heuristics that are able to obtain good solutions for the problem in a short CPU time. In particular, constructive heuristics are available for the problem such as that by Fredendall and Lea, and by Aryanezhad and Komijan. We propose a new constructive heuristic based on the Theory of Constraints and the Knapsack Problem. The computational results indicate that the proposed heuristic yields better results than the existing heuristic.