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11.
Arterial wall thickening may be quantitatively assessed by measuring the intima-media thickness (IMT) with high resolution ultrasound. Previous studies have shown a good inter/intraobserver variability of IMT measurements in the common carotid. In this study we evaluated the inter/intraobserver variability of IMT measurements in 10 randomly selected asymptomatic subjects (age 55.4 +/- 6). Two carotids and two femorals were studied in each subject. IMT for each patient was the average of five IMT measurements at the artery bifurcation. Three observers repeated the scanning and the measurements twice with no knowledge of the previous readings. The between observer coefficient of variation (CV) was 8.45%; the intraobserver CV (mean of carotids and femorals) varied from 4.4 to 5.1% for the three observers who measured IMT three times. The mean absolute difference between the first and the third measurement was 0.0738 mm. In conclusion IMT measurement variability is mostly due to differences between observers. The intraobserver variability is very small. IMT measurements at the carotid and femoral bifurcations have a low variability and are a good expression of atherosclerosis as they consider early lesions at the bifurcation level which may not be observed in the common carotid. 相似文献
12.
Two deacetyl-thymosin β4 analogues containing Phe(4Br) or D-Phe(4Br) as position 12 were synthesized by the manual solid-phase method, and their immunological effects on the impaired blastogenic response of phytohemagglutinin-stimulated T lymphocytes of uremic patients with infectious diseases were studied. Bromination of the p-position of Phe12 resulted in a marked restorative effect on the impaired blastogenic response of T lympocytes compared with that of our synthetic deacetyl-thymosin β4 The synthetic [Phe(4Br)12]deacetyl-thymsin β4 was approximately equal in potency to our synthetic [Phe(4F)12]deacetyl-thymosin β4 in uremic patients, but the other analogue, [D-Phe(4Br)12]deacetyl-thymosin β4, had no effect. 相似文献
13.
Mita T. Hirata M. Murata K. Zhang H. 《Industrial Electronics, IEEE Transactions on》1998,45(3):488-495
In the motion control field, a disturbance observer-based disturbance canceling control is often used as a robust control methodology. However, this method is nothing more than an alternative design of an integral controller, and the robust stability issue cannot be directly accounted for. In this paper, an extended H∞ control scheme is proposed as a new robust motion control method which achieves the disturbance cancellation ability and guarantees robust stability automatically 相似文献
14.
For a three-dimensional (3-D) Cherenkov laser composed of a dielectric-loaded rectangular waveguide and a finite-width planar relativistic electron beam, the nonlinear characteristics and efficiency enhancement are investigated with the aid of particle simulation, allowing for the nonlinear properties of the electron beam. The numerical results obtained in the paper are compared with those obtained in the two-dimensional (2-D) analysis. The efficiency enhancement scheme, which was previously proposed for the 2-D case, is found to be effective also for the 3-D case 相似文献
15.
Keishi Sakamoto Atsushi Kasugai Masaki Tsuneoka Koji Takahashi Yukiharu Ikeda Tsuyoshi Imai Takashi Nagashima Mitsuru Ohta Tsuyoshi Kariya Kenichi Hayashi Yoshika Mitsunaka Yosuke Hirata Yasuyuki Itoh Yukio Okazaki 《Journal of Infrared, Millimeter and Terahertz Waves》1997,18(9):1637-1654
A development of 170GHz/500kW level gyrotron was carried out as R&D work of ITER. The oscillation mode is TE31,8. In a short pulse experiment, the maximum power of 750kW was achieved at 85kV/40A. The efficiency was 22%. In the depressed collector operation, 500kW/36%/50ms was obtained. The maximum efficiency of 40% was obtained at PRF=470kW whereas the power decrease by the electron trapping was observed. Pulse extension was done up to 10s at PRF=170kW with the depressed collector operation. The power was limited by the temperature increase of the output window. 相似文献
16.
The oxidation of Fe(II) with dissolved molecular oxygen was studied in sulfuric acid solutions containing 0.2 mol . dm-3 FeSO4 at temperatures ranging from 343 to 363 K. In solutions of sulfuric acid above 0.4 mol . dm-3, the oxidation of Fe (II) was found to proceed through two parallel paths. In one path the reaction rate was proportional
to both [Fe2+]2 and po2, exhibiting an activation energy of 51.6 . kJ mol-1. In another path the reaction rate was proportional to [Fe2+]2, [SO4-], and po2 with an activation energy of 144.6 kJ . mol-1. A reaction mechanism in which the SO4- ions play an important role was proposed for the oxidation of Fe(II). In dilute solutions of sulfuric acid below 0.4 mol
. dm-3, the rate of the oxidation reaction was found to be proportional to both [Fe(II)]2 and Po2, and was also affected by [H+] and [SO2-
4]. The decrease in [H+] resulted in the increase of reaction rate. The discussion was further extended to the effect of Fe (III) on the oxidation
reaction of Fe (II). 相似文献
17.
I Hirata S Kimura T Michihata H Osawa M Kume T Kashima 《Canadian Metallurgical Quarterly》1997,45(8):1173-1177
A 66-year-old male with Beh?et's disease admitted again with hemoptysis. He underwent the resection and direct closure of descending aortic aneurysm 3 years ago, followed without the use of steroid. Chest CT scanning demonstrated a recurrent aneurysm of the descending aorta which was could not be detected on the previous CT only 23 days before. In the current operation, we performed resection, direct closure and wrapping of the aneurysm. The pathological examination showed a true aneurysm of Beh?et's disease. The patient is free from recurrence for 17 months since the operation under steroid therapy. 相似文献
18.
A molecular orbital approach to materials design has recently made great progress. This approach is based on the electronic structure calculations by the DV-Xα cluster method. In this paper recent progress in this approachis reviewed. In particular 相似文献
19.
Highly transparent cellulose hydrogels with physical crosslinkage were prepared from nonaqueous organic cellulose solutions and viscose by coagulating and regenerating cellulose in an aqueous solution containing a water‐miscible organic solvent. Nonaqueous organic cellulose solutions used were LiCl/dimethylacetamide, paraformaldehyde/dimethyl sulfoxide, and triethylammonium chloride/dimethyl sulfoxide. Preparation conditions and physical properties of the transparent cellulose hydrogels were studied. The transparency of the cellulose hydrogels depended on the composition of the aqueous solution containing the organic solvent. Furthermore, transparent cellulose hydrogels from viscose showed high tensile strength. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3020–3025, 2003 相似文献
20.