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41.
We have previously shown that an oral glucose load increased both calciuria and oxaluria while the ingestion of fructose induced a rise in calciuria and a decrease in oxaluria. This latter effect remains unclear and might be linked to the reduced intestinal oxalate absorption subsequent to digestive intolerance in some subjects. Such a hypothesis could be enlightened by the study of a parenteral fructose load. Therefore in 7 healthy subjects, we compared the effects of fructose infusion (F) (15 min iv infusion at 0.185 mmol/kg BW/min) to a control glucose infusion (G) on urinary calcium and oxalate. In this study, glycemia and insulinemia increased less after (F) than after (G) (respectively + 21% vs + 216%, p < 0.001 and + 230% vs + 402%, p < 0.05) and phosphatemia decreased less after (F) than after (G) (-7% vs -14%, p < 0.05). Urinary calcium and oxalate increased only after (F) (respectively + 64%, p < 0.01 and + 60%, p < 0.05). Urinary uric acid, another urolithiasis factor, increased after both (F) and (G) (respectively + 45%; p < 0.01 and + 42%; p < 0.01) but uricemia increased only after (F) (+ 25%; p < 0.01). Our results suggest an additional reason to avoid the use of fructose in parenteral nutrition, particularly in individuals with a known history of either calcium oxalate or urate urolithiasis.  相似文献   
42.
We consider ad hoc wireless networks that use directional antennas and have limited energy resources. To explore quantitatively the advantage offered by the use of directional antennas over the case of omnidirectional antennas, we consider the case of connection-oriented multicast traffic. Building upon our prior work on multicasting algorithms, we introduce two protocols that exploit the use of directional antennas and evaluate their performance, We observe significant improvement with respect to the omnidirectional case, in terms of both energy efficiency and network lifetime. Additionally, we show that further substantial increase in the network's lifetime can be achieved by incorporating a simple measure of a node's residual energy into the node's cost function.  相似文献   
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A new compact millimeter-wave distance-measurement sensor prototype has been developed. The sensor is a step-frequency radar implemented using coherent heterodyne technique. It operates in Ka-band (26.5-40 GHz) and is realized using MICs and MMICs. The sensor transmits sinusoidal signals of incremental frequencies and demodulates the received signals into base-band I/Q signals for processing. Experimental results show that the sensor is capable of measuring distance with less than 0.2 inch of absolute error and a low transmitted power of only -20±3 dBm  相似文献   
45.
We investigated predisposing factors for the development of heterotopic ossification in a retrospective study of 637 hip arthroplasties, of which 484 were unilateral, 62 bilateral and 29 revision operations. The frequency of heterotopic ossification after a primary hip arthroplasty was 57 percent. In a univariate analysis, men, patients with hypertrophic arthrosis, and cemented arthroplasty were all at risk of developing heterotopic ossification. After a multivariate analysis, the male sex and the cemented arthroplasty remained as significant factors. In bilateral operations, the contralateral side developed heterotopic ossification in 82 percent when the primary hip operation had already caused ossification. There was no increase in ossifications after the contralateral operation. Half of the revision operations had an increase of heterotopic ossification from 1 to 4 Brooker classes.  相似文献   
46.
OBJECTIVE: To study the effects of thevetoside (TS), a cardiac glycoside, and an inhibitor of Na+, K(+)-ATPase, on tumor cells cultured in vitro. METHODS: The cytotoxic effects of TS on tumor cells were determined by trypan blue dye exclusion, neutral red vital staining and clonogenic assay. The time-effect relationship and growth inhibition of tumor cells by TS were assayed with trypan blue exclusion method. RESULTS: TS at low doses (0.005-0.1 mg.L-1), with dose dependence, was able to kill SMMC-7721, SGC-7901 and HeLa cells. IC50 values for SMMC-7721, SGC-7901 and HeLa cells were 0.007, 0.011 and 0.018 mg.L-1 by trypan blue dye exclusion test and 0.016, 0.055 and 0.078 mg.L-1 by neutral red vital staining test. TS inhibited the clonal forming rate of SMMC-7721 and SGC-7901 significantly with IC50 values of 0.021 and 0.036 mg.L-1, respectively. Only when the cells were continuously treated with TS for more than 8 hours, the drug-induced cell lethality could be displayed and strengthened quickly. The growth of tumor cells was notably inhibited after they were exposed to 0.1 microgram/ml of TS for 12 hours. All the experimental results of antitumor activity in vitro showed that SMMC-7721 was most sensitive to TS among the three kinds of tumor cells. CONCLUSIONS: TS has cytotoxic action on tumor cells cultured in vitro and this lethal effect must have an action process, in which tumor cells are not dead but suffer from deadly injury and lost the capability of unlimited proliferation.  相似文献   
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48.
Primary graft rejection after marrow transplantation occurs more frequently in patients receiving HLA-haploidentical compared with HLA-identical sibling transplants. Both human and experimental animal data suggest that the cells responsible for this phenomenon are either host natural killer (NK) cells, T cells, or both. To investigate the mechanisms of graft rejection, we have developed a canine model of marrow transplantation, which uses DLA-nonidentical unrelated donors in the absence of postgrafting immunosuppression. In this model most animals rejected their marrow grafts after a preparative regimen of 9.2 Gy total body irradiation (TBI). However, engraftment of DLA-nonidentical marrow can be facilitated when the recipients are pretreated with monoclonal antibody (MoAb) S5, which recognizes CD44. In this report, we extended these observations by first cloning the canine CD44 and, next, mapping the epitope recognized by S5, which was located in a region conserved among human and canine CD44 and was distinct from the hyaluronan binding domain. However, in vitro binding of S5 caused a conformational change in CD44, which allowed increased hyaluronan binding. Then, we reexamined the in vivo model of marrow transplantation and compared results with MoAb S5 to those with two other anti-CD44 MoAbs, IM7 and S3. Only MoAb S5 significantly increased the engraftment rate of DLA-nonidentical unrelated marrow, whereas the two other anti-CD44 MoAbs were ineffective. The enhanced in vivo effect was not related to differences in the MoAbs' avidities, since both S5 and IM7 had equivalent binding to CD44, but most likely related to the specific epitope that S5 recognizes. Thus, this study shows that the effect of the anti-CD44 MoAb S5 in facilitating engraftment is epitope specific and if one is to use an anti-CD44 to facilitate engraftment of marrow in humans, one cannot assume that any anti-CD44 would work.  相似文献   
49.
Our previous receiver operating characteristic (ROC) study indicated that the detection accuracy of microcalcifications by radiologists is significantly reduced if mammograms are digitized at 0.1 mm x 0.1 mm. Our recent study also showed that detection accuracy by computer decreases as the pixel size increases from 0.035 mm x 0.035 mm. It is evident that very large matrix sizes have to be used for digitizing mammograms in order to preserve the information in the image. Efficient compression techniques will be needed to facilitate communication and archiving of digital mammograms. In this study, we evaluated two compression techniques: full frame discrete cosine transform (DCT) with entropy coding and Laplacian pyramid hierarchical coding (LPHC). The dependence of their efficiency on the compression parameters was investigated. The techniques were compared in terms of the trade-off between the bit rate and the detection accuracy of subtle microcalcifications by an automated detection algorithm. The mean-square errors in the reconstructed images were determined and the visual quality of the error images was examined. It was found that with the LPHC method, the highest compression ratio achieved without a significant degradation in the detectability was 3.6:1. The full frame DCT method with entropy coding provided a higher compression efficiency of 9.6:1 at comparable detection accuracy. The mean-square errors did not correlate with the detection accuracy of the microcalcifications. This study demonstrated the importance of determining the quality of the decompressed images by the specific requirements of the task for which the decompressed images are to be used. Further investigation is needed for selection of optimal compression technique for digital mammograms.  相似文献   
50.
The purpose of this study is to evaluate the effect of one abrasive cleaner, one non-abrasive cleaner and one non-abrasive alcohol-based cleaner on the lens parameter stability of the NOVALENS. Twenty-four lenses, all NOVALENS material of identical design, were cleaned 100 times each. Eight lenses were cleaned with MiraFlow (CIBA Vision), eight lenses with Optic-Free Daily Cleaner and eight lenses with the Gas Permeable Daily Cleaner (PBH). The base curve radius, center thickness and power were verified immediately before, immediately after and (per manufacturer's recommendation) 4 hours after cleaning at baseline, 25, 50, 75 and 100 cleanings. Lens toricity of approximately 0.50D was found with all three cleaners after 100 cleanings. No change in lens power or center thickness was found. It was concluded that extreme care must be taken in handling the NOVALENS due to the potential of induced warpage.  相似文献   
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