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991.
It has recently been reported that there exists a new 'RING-finger' protein family among the zinc-finger (Zf) proteins. Previously, we had isolated the mouse Mel-18 cDNA (mMel-18) encoding the nuclear RING-finger protein that exhibits an ability to bind to a nonspecific DNA column. Here, we have isolated and characterized the human Mel-18 cDNA (hMel-18) using the mMel-18 cDNA as a probe. The deduced hMel-18 protein contains 344 amino acids (38 kDa) with a RING-finger motif, a helix-loop-helix (HLH)-like structure and a Pro/Ser-rich region. The hMel-18 gene is conserved among vertebrates. Its mRNA is highly expressed in placenta, lung and kidney, but the level is low in liver, pancreas and skeletal muscle. Using in situ hybridization, we mapped hMel-18 to band q22 of chromosome 12. It is possible that the Mel-18/bmi-1 gene family represents a mammalian homologue of the Drosophila polycomb gene group.  相似文献   
992.
993.
The dissolution of titanium in simulated interstitial electrolyte (SIE), human serum in SIE (serum/SIE) and 8.0 mM ethylenediaminetetraacetic acid (EDTA) in SIE (EDTA/SIE) was measured in vitro. Titanium fibre samples were immersed in these solutions and maintained at 37°C, 10% O2, 5% CO2 and 97±3% relative humidity for 0–5000 h. The concentration of titanium released was quantified using electrothermal atomic absorption spectroscopy. Changes in oxide stoichiometry were determined by Auger electron spectroscopy after processing and immersion in the test solutions. The oxide became nearly stoichiometric TiO2 after immersion, suggesting equilibration of the surface with the solutions. Solution ligands enhanced the magnitude of dissolution, with EDTA>serum/SIE>SIE. The dissolution kinetics were empirically fitted by a two-phase logarithmic relationship. The first phase of dissolution (t<300 h) was dominated by equilibration of the oxide with the solution and the second phase (t>300 h) by mass diffusion. The dissolution kinetics were similar for the EDTA/SIE and serum/SIE solutions, indicating that the mechanisms of dissolution for each solution may be the same.  相似文献   
994.
Previously, we have shown that embryonic day 12 thymus anlage cultured alone cannot develop into the mature organ but degenerates. In the present study, we investigated the cause of this insufficient organogenesis of embryonic day 12 thymus anlage in organ culture. We cocultured embryonic day 12 thymus anlages with various cell lines as pellets formed by centrifugation. In coculture with fibroblastic cell lines, but not with thymic epithelial cell lines, embryonic day 12 thymus anlages developed to support full T cell differentiation, and expressed mature stromal cell markers, Ia and Kb. By pellet culture of thymus anlages and fibroblastic cell lines transfected with a beta-galactosidase expression vector, we analyzed the distribution of added fibroblastic cells in pellets. The added fibroblastic cells constituted neither thymic capsule nor septa but disappeared after about 2 weeks in culture. Moreover, immunohistochemical studies indicated that added fibroblastic cells were adjacent to mesenchymal cells of thymus anlage. Our results strongly suggest that added fibroblastic cells support the development of the thymus anlage through interaction with its mesenchymal cells.  相似文献   
995.
A high common mode voltage (Vcm) relative to earth ground is produced on the myocardium during the delivery of a defibrillator pulse and can generate a differential error signal when potential gradients are recorded with bipolar electrodes and isolation amplifiers. The error signal is proportional to Vcm, and therefore, a reduction in Vcm improves the accuracy of the potential gradient data. Experiments were conducted on 5 dogs to determine whether Vcm can be controlled using a bridge circuit. The bridge circuit consisted of a 5 kΩ power rheostat in parallel with the transthoracic resistance of the dog. The variable contact of the rheostat was connected to earth ground, and by adjusting the rheostat, Vcm on the myocardium could be varied. In each dog, 20 A shocks were delivered through stainless steel transthoracic electrodes. Point contact electrodes sutured to the epicardium were used to measure Vcm. It was determined that Vcm could be reduced to approximately zero at a given electrode on the heart. In addition, for the 5 dogs studied, the maximum measured Vcm on the heart was only 10% of the transthoracic voltage when the bridge circuit was balanced for an interior point in the heart  相似文献   
996.
Persistence of the hypoglossal artery is an unusual congenital abnormality of the carotid arterial system, and the simultaneous occurrence of atheromatous disease in the internal carotid artery and persistent hypoglossal artery is even more uncommon. Carotid surgery in this situation is challenging, and the surgeon must be aware of potential inherent pitfalls. A 74-year-old woman with asymptomatic stenosis of both internal carotid and hypoglossal arteries associated with occlusion of the contralateral internal carotid artery underwent successful revascularization. The anatomy of this unusual lesion and the surgical strategies, which included cranial nerve dissection and mandibular subluxation, are reviewed.  相似文献   
997.
The anisotropy of the resistivity and thermoelectric power (TEP)S of Nd1.85Ce0.15CuO4?δ single crystal (T c =17 K) has been investigated. In the temperature rangeT c <T<300 K the ratioρ cab≈104 and the dependencesρ ab (T) andρ c (T) change from quadratic to linear atT~200 K. The dependencesS ab (T) andS c (T) reach a maximum atT>T c and then decrease almost linearly with increasing temperature, changing sign from positive to negative nearT~ 150 K. The features of the resistivity and TEP temperature dependences (the lawρT 2 changing toρ∝T, the change in the sign of S with temperature, and the low TEP anisotropy at largeρ anisotropy) have been interpreted in the framework of the narrow-band model.  相似文献   
998.
At the university hospital of emergency surgery in Innsburck and at the emergency services department of the hospital in Schwaz, anterior cruciate ligament reconstruction was performed in 467 patients between January 1992 and September 1993. In 117 cases, a double semitendinous tendon was used as an autograft. A total of 60 of these patients were followed up at an average of 20 months (13-33) after reconstruction. The results were rated according to the OAK and the Tegner scores. Objective measurements of instability were carried out by a KT 1000 arthrometer. In addition, 21 patients underwent computer-interfaced dynamometer testing using a Cybex 6000. Standardized loading of the thigh muscles was performed at angular velocities of 60 degrees/s (3 repetitions) and 240 degrees/s (30 repetitions): peak torques and total work were analyzed. The mean age was 23.5 years (17-55): 48 were male, 21 female. The main reasons for the ACL ruptures were sports injuries (51 cases). The patients were classified into three groups according to the data of the repair (group 1 reconstruction up to 1 week after trauma-28 patients: group 2: reconstruction between the 2nd and 6th week after trauma-15 patients: group 3: reconstruction 6 and more weeks after trauma-26 patients). In group 1. additional ruptures of the menisci. lesions of the MCL. and chondromalacia were seen in 71.4%. in group 2 in 73.3% and in group 3 in 80.8%. The average rating in the OAK score was 90.16 points: 38 patients (55.70%) had excellent results. 18(26.09%) were good. 9(13.04%) were fair and 4(5.80%) were poor. The Tegner activity score showed a reduction of 0.36 points on average. The largest amount of anterior translation was performed with the KT 1000 manual drawer test (2.29 mm on average compared with the contralateral side). Dynamometer testing showed a statistically significant difference in flexor and extensor mechanism (compared with the non-involved side) in both peak torques and total work. A repeat arthroscopy became necessary in five cases: arthrofibrosis in three and incipient joint infection in two cases.  相似文献   
999.
Rectangular waveguides with two L-shaped septa attached to the broad walls in antipodal configuration have been shown theoretically by the authors (see ibid. vol.40, no.4, p.777-781, 1992) to be an improved variant of the double T-septa guide having larger cut-off wavelength and broader bandwidth of the dominant TE mode. Numerical data on the attenuation, impedance, and power handling capability of this new type of broadband guide are presented as additional design information  相似文献   
1000.
A new minimum zone method for evaluating flatness errors   总被引:1,自引:0,他引:1  
A new minimum zone method for flatnes error analyis is proposed in this article. Based on the criteria for the minimum zone solution and strict rules for data exchange, a simple and rapid algorithm, called the control plane rotation scheme, is developed for the flatness analysis of a flat surface. Experimental work was performed, and some examples are given in terms of the minimum zone and least-squares solutions.  相似文献   
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