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The characteristics of objective lenses and Ca2+-sensitive probes were examined for imaging with a two-photon laser-scanning microscope (TP-LSM). The brightness of the images of beads taken by different objectives greatly varied and depended predominantly on their numerical aperture (NA) and less on transmittance and chirping effects. Lateral and axial resolutions, dx and dz, defined as the half decay length of fluorescence intensity of the image of a spherical bead (0.3 m) were 0.12 and 0.42 microm (objective; 40x/0.75). They are far better than those of confocal microscopes (0.3 and 1.5 microm, respectively) measured similarly (Kuba et al., 1994). dx linearly increased with an increase in 1/NA, while dz linearly increased with an increase in n/(NA)2 (n, refractive index) except for an objective of large NA (1.3). The coverslip compensation of objective lenses greatly affected the shape of the X-Z scanned images of 5.0 microm beads as well as resolutions, indicating a large effect of spherical aberration. Two-photon excitation spectra of Ca2+-sensitive fluorescent probes, indo-1, fura-2 and Oregon Green BAPTA-1, lied in a wavelength range shorter than twice that activated by one-photon absorption, while emission spectra were unchanged. Three-dimensional images of a cultured hippocampal neurone loaded with Oregon Green BAPTA-1 showed fine structures of spines, dendrites and axons, while imaging with FM1-43 localized presynaptic boutons and demonstrated synaptic vesicle turnover. Dyes bleached little during the recording of 100 sectioned images. These characteristics of TP-LSM as well as its ability to image deeper tissues provide excellent means to study dynamic, spatial changes in intracellular substances and structures. To achieve the good performance of a TP-LSM, however, the relevant usage of appropriate objectives and fluorescent probes are required. 相似文献
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Many studies have shown the high correlation between Lunar and Hologic DXA bone mineral density (BMD) measurements despite differences in absolute calibration. However, in clinical practice, raw BMD values (in g/cm2) are not normally used for assessing skeletal status and fracture risk. Instead, the BMD values are expressed in terms of the number of standard deviations above or below the young normal value (commonly referred to as the T-score). If the normative populations of the various systems are consistent, the standard deviation scores should also be consistent. For this reason, the World Health Organization (WHO) recently established diagnostic criteria for osteoporosis based on T-scores and not BMD. However, few studies have compared the instruments in terms of their standard deviation scores. In this study, we used linear regression to compare T-scores in 83 women at L1-4 and 120 women at the femoral neck obtained on a Lunar DPX and a Hologic QDR-1000/W system. patient BMD and T-score measurements were highly correlated between the two systems (r > 0.95). No clinically significant difference in L1-4 T-scores was seen (less than 0.1 SD). However, linear regression analysis confirmed a systematic difference of 0.9 SD between the femoral neck T-scores. This discrepancy is caused by: (1) differences in the normal populations, and (2) differences in statistical models used to determine the young normal mean and standard deviation. In an attempt to correct the discrepancy, the female young normal mean and standard deviation were recalculated for the femoral neck using published epidemiological data from NHANES and existing DXA cross-calibration equations. The Hologic young normal value (mean +/- SD) was redefined as 0.85 +/- 0.11 g/cm2, while the Lunar value was redefined as 1.00 +/- 0.11 g/cm2. When the femoral neck T-scores for the study population were recalculated on the basis of these new values, the results were equivalent between manufactures, effectively eliminating the discrepancy. However, the revised values should be confirmed by additional measurements in young normal adults. 相似文献
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More than 600 cases of ovarian tumors were analyzed for histological type, age of patient, bilateral occurrence, mobility and malignant degeneration in restant ovaries. Tumors of germinal epithelial origin show the highest incidence (24%) of malignant degeneration, tumors of germ cells the lowest (3,5%). Incidence of malignant degeneration increases in relation to the age of the patient from 2% (and under 30 years) to 36,5% (60-70 years). Each form of tumor has its typical age peak, which is about 20 years higher for carcinomas than for their benign counterpart. Bilateral ovarian tumors are malignant in 29%, one-sided only in 13%. Among freely movable ovarian tumors, only 6% enclose a malignant tumor, among adhaerent ones 34%. The examination of the prognosis of granulosacell-tumors, dysgerminomas and teratoblastomas is based on a larger material. 相似文献
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Granulomas and cholestatic--hepatocellular injury associated with phenylbutazone. Report of two cases 总被引:1,自引:0,他引:1
A combined cholestatic-hepatocellular injury and noncaseating granulomas occurred in two patients 1 and 4 weeks after phenylbutazone therapy. Both patients were jaundiced, one had a macular rash, and both had peripheral blood eosinophilia. Symptoms and signs subsided, and abnormal findings from tests of hepatic function rapidly returned to normal following withdrawal of the drug. Sections of liver biopsy specimens 6 months later showed no granulomas or other pathologic changes. Previously reported cases are reviewed. 相似文献
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The European Cognitive Vision project VAMPIRE uses mobile AR-kits to interact with a visual active memory for teaching and retrieval purposes. This paper describes concept and technical realization of the used mobile AR-kits and discusses interactive learning and retrieval in office environments, and the active memory infrastructure. The focus is on 3D interaction for pointing in a scene coordinate system. This is achieved by 3D augmented pointing, which combines inside-out tracking for head pose recovery and 3D stereo human–computer interaction. Experimental evaluation shows that the accuracy of this 3D cursor is within a few centimeters, which is sufficient to point at an object in an office. Finally, an application of the cursor in VAMPIRE is presented, where in addition to the mobile system, at least one stationary active camera is used to obtain different views of an object. There are many potential applications, for example an improved view-based object recognition. 相似文献