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1.
This paper presents applications of microwaves and millimeter waves for the characterization of teeth. This is done by measuring the complex permittivity over the frequency range from 0.04 to 40 GHz. These measurements have revealed that dental caries are significantly more lossy to microwaves and millimeter waves than the healthy tooth, and this difference can be used for dental diagnosis. The experimental results have been confirmed by using the finite-difference time-domain (FDTD) method. In addition, millimeter-wave heating of the lossy dental caries can be used as a sterilization treatment. It is concluded that millimeter waves can be used for dental medical diagnosis as well as dental medical treatment 相似文献
2.
Within the context of an extensive study of electroconvulsive therapy at the Psychiatric Clinic of the University of Bonn 15 patients suffering from therapy-resistant Major depression (DSM III-R) were examined with a detailed psychometric test battery, containing memory- and nonmemory tests. The test battery had been applied short time before, during and after the treatment with 10 ECT applied unilateral over the nondominant hemisphere. Comparing the test performances before and 1-2 days after the end of the series there were only few remarkable changes: a significant decrease was diagnosed exclusively in 30 min delayed recall of verbal items, while visual short-term memory and visual-constructive performance showed a significant improvement (in spite of unilateral stimulation on the right side). None of the other cognitive functions inclusively speed of performances and reaction time was detracted short time after the end of the ECT-treatment, instead all the measures improved albeit not significantly. Between responders to treatment (50% improvement in HAMD) and non-responders no significant differences neither before nor after the treatment were detected. The non-responders had in nearly all of the tests some better (but not significantly) results despite being older than the group of responders. 相似文献
3.
BACKGROUND: The study was carried out to evaluate the correlation between blood-retinal barrier (BRB) permeability and the progression of diabetic retinopathy (DR), defined by development of "need for photocoagulation", over a 7-year period by means of vitreous fluorometry (VF). METHODS: Forty type 2 diabetic patients with minimal or no retinopathy, aged 40-65 years (mean 53.9 + 7.3 years), were followed up prospectively for 7 years. Investigations including standard ophthalmological examination, fundus photography, fluorescein angiography and VF were performed at entry and 1, 4, 5 and 7 years later. Only one eye per patient was included in the study. Need for photocoagulation was based on Early Treatment Diabetic Retinopathy Study protocols and decided by the attending ophthalmologist. RESULTS: After 7 years of follow-up a total of 22 of the 40 eyes had received photocoagulation. The eyes that needed photocoagulation were those that had higher VF values at the entry of the study and showed higher rates of deterioration (initial values 5.1 + 1.9 vs 2.8 + 1.5 x 10(-6) min-1, P < 0.001; annual increase in leakage for the first year, 1.5 + 0.8 vs 0.5 + 1.0 x 10(-6) min-1, P < 0.001,). The eyes that did not need photocoagulation during the 7 years of follow-up showed stable VF readings (-0.1 + 1.2 x 10(-6) min-1, difference between initial values and 7 years later). CONCLUSIONS: Abnormally high VF values and their rapid increase over time are good indicators of progression and worsening of the retinopathy in diabetes type 2. 相似文献
4.
Yoshio Ebisu 《Metallurgical and Materials Transactions B》2011,42(2):341-369
A numerical method for analyzing solidification phenomena of multicomponent alloys is presented. This method consists of macroscopic
transport governing equations expressed in terms of a nonlinear multicomponent alloy model, which is coupled with the microscopic
dendritic solidification model to estimate permeability. Numerical simulations were performed for channel segregation in a
steel ingot and for freckles in a Ni-base IN718 remelted ingot and in Ni-10 wt pct Al directionally solidified (DS) ingots.
The results show good agreement with experimental observations. The electromagnetic (EM) braking effect by static magnetic
field was incorporated into the numerical method, and the anisotropic behavior of magnetic field was investigated on the DS
Ni-10 wt pct Al ingots. Application of relatively low magnetic fields in the transverse to the growth direction (B
x
or B
y
) resulted in formation of distorted freckles as a result of the nonuniform liquid flow induced in the transverse direction.
It is shown that a considerably high magnetic field is required to suppress the distorted freckles and other freckles developed
in longitudinal direction. However, there is a risk of the breakdown of DS. On the other hand, when applying the magnetic
fields parallel to the growth direction (B
z
), the number of freckles inversely increased at low magnetic fields, but the freckles were eliminated by about the same level
of high magnetic field as that of B
x
or B
y
. Because the parallel magnetic field suppresses the liquid flow vector components uniformly within the transverse plane,
the nonuniform flow does not occur in the transverse directions. As a result, it suppresses the flow in the growth direction.
It is envisioned that the application of the parallel magnetic field is beneficial in the commercial production of DS castings. 相似文献
5.
Kazuyuki Yagi Yukito Ebisu Joichi Sugimura Seiji Kajita Toshihide Ohmori Atsushi Suzuki 《Tribology Letters》2011,43(3):361-368
In this study, a direct observation of a point contact area was conducted to understand the scuffing phenomenon. The contact
area was produced between a rotating sapphire disc and a stationary steel ball and it was lubricated using n-hexadecane. The image detected by a colour digital CCD camera, load, and friction were synchronously recorded by a computer
during the test. It was found that wear debris produced in the contact area played an important role in the wear process,
which includes running-in and scuffing. In the test, debris particles accumulated in the inlet zone, and some particles entered
the contact area to cause abrasive wear of the ball surface, even in the light-load stages. During the running-in process,
the abrasive wear by debris particles changed the conformity between the sliding surfaces. In the high-load stage, just before
the occurrence of scuffing, the whole contact area was flattened at once. When scuffing occurred, the contact area suddenly
expanded. The conformity of the contact area was dramatically changed during its expansion. The flattening of the whole contact
area and dramatic expansion with changing the conformity seemed to play important roles in scuffing. 相似文献
6.
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. 相似文献
7.
Azakami H Teramura I Matsunaga T Akimichi H Noiri Y Ebisu S Kato A 《Journal of Bioscience and Bioengineering》2006,102(2):110-117
Quorum sensing (QS) is a process by which bacteria communicate using secreted chemical signaling molecules called autoinducers (AIs). By this process, many bacterial species modulate the expression of a wide variety of physiological functions in response to changes in population density. In this study, the periodontal pathogen Eikenella corrodens was observed to secrete type 2 signaling molecules. An ortholog of luxS, the gene required for AI-2 synthesis in Vibrio harveyi, was isolated from the E. corrodens genome. A V. harveyi bioassay showed luxS functionality in E. corrodens and the ability of luxS to complement the luxS-negative phenotype of Escherichia coli DH5alpha. AI activity was detected in the supernatant, and the maximum expression of AI-2 was observed during the late exponential phase. To determine the potential role of luxS in the colonization processes, an E. corrodens luxS mutant was constructed and tested for its capacity to form an in vitro biofilm on a polystyrene surface. The biofilm forming efficiency of the luxS mutant was approximately 1.3-fold greater than that of the wild type. These data suggest that a LuxS-dependent signal plays a role in the biofilm formation by E. corrodens. 相似文献
8.
Nakano T Tokumura A Umakoshi Y Imazato S Ehara A Ebisu S 《Journal of materials science. Materials in medicine》2001,12(8):703-706
Crystallinity of hydroxyapatite reflecting crystal size and crystal elastic strain was controlled by the mechanical grinding (MG) technique using a set of container and balls made of SUS304 stainless steel or agate. Variation in the crystallinity through MG was monitored by the XRD method and represented by the broadening of the diffraction peak. Effect of changes in crystallite size and strain on the crystallinity was also examined using the Hall-plot method.Crystallinity rapidly decreased with milling time. Significant crystallographic diffraction peaks disappeared and a broad diffraction around 2=32° was observed after MG for 72 h. The broadening was dominantly due to an increase in crystal strain in addition to fine crystallite size. Contamination from the container and balls during MG was more suppressed using agate than SUS304 stainless steel.The recovery process of crystallinity during heating between 300 °C and 1200 °C was examined focusing on the decrease in residual elastic strain. Low crystallinity was maintained at annealing temperatures below 800 °C but lattice defects were recovered above 1000 °C.© 2001 Kluwer Academic Publishers 相似文献
9.
10.
The process of retirement planning is a difficult one for a physician. The Planning process should address the areas of Investment Planning, Estate Planning, and Risk Management. This article examines each of these dimensions with special emphasis on Modern Portfolio Theory as the basis for investment planning. 相似文献