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1.
Trisomy 18 is a chromosomal disorder giving multiple anomalies. Its frequency depends on maternal age. We report a 28-year-old woman in her first pregnancy, who underwent first trimester scanning for screening. Due to increased nuchal translucency and exomphalos, chorionic villous sampling was performed. Cytogenetic diagnosis was trisomy 18 and termination of pregnancy was carried out immediately.  相似文献   
2.
A population-based probability sample of elderly individuals (n = 426), who were originally studied between 1981 and 1986 (mean age at initial study was 72.5 years), were followed for mortality. Those with > or = 30 respiratory disturbances per hour of sleep had significantly shorter survival (p = 0.0034), but the respiratory disturbance index (RDI) was not an independent predictor of death. When Cox proportional hazards analysis was done, only age (the strongest predictor), cardiovascular disease and pulmonary disease were independent predictors of death. It may be that factors that are secondary to or associated with sleep-disordered breathing (SDB), such as cardiovascular or pulmonary disease, predispose these elderly to death.  相似文献   
3.
Photoadditions of ethylene and of cyclopentene to Δ4 - and Δ4,6-3-ketosteroids gave mixtures of cis -4α,5α and trans -4α. 5β adducts. In the case of cyclopentene and Δ4,6-androstadiene-3-one-17β-ol propionate, only the trans adduct was observed. Cis -4β,5β adducts were obtained by base-catalyzed isomerization of the trans adducts. The ratio of cis:trans adducts varied considerably with solvent, temperature, and olefin concentration in steroid reactions but not in reactions with cyclohexenone. The different types of adducts exhibited markedly different ORD curves in agreement with the structures assigned. Carbonyl maxima of trans adducts appeared at shorter wavelengths than maxima of cis adducts in both infrared and ultraviolet spectra. The infrared shifts provide a convenient method for differentiating between cis and trans fused isomers.  相似文献   
4.
In a probabilistic analysis of a stochastic structure, it is important to identify the design point—the point of most probable failure. When both the resistance and load term of the limit state function are random, a modified joint probability density function is formulated, and the design point is obtained by searching for the maximum point of this function. The modification is done by introducing the finite element solution for the load term into the original basic joint probability density function of the random variables. For threshold value problems, the design point is obtained by searching for the maximum point of the original joint probability function, conditional upon the finite element solution being equal to the threshold value. Once the design point is identified, the index of reliability can be found using known techniques for structures with independent and dependent random variables, normally and non-normally distributed. The solution is obtained without the need for any derivatives of the load term with respect to the random variables, thus no modifications are required in the finite element code used. The solution requires an algorithm that finds the maximum value of the objective function in a well defined variable space. Several numerical examples are presented, including cases of random fields, which are discretized by stochastic finite element into random variables. The library module of design optimization of the finite element code employed (ANSYS) is used to find the design point. Applying the proposed method permits the designer to perform probabilistic analysis with computational tools already available.  相似文献   
5.
Scintigraphic methods used in intraoral and extraoral implantology allow the evaluation of bone metabolism in the peri-implant zones, providing anatomic images and functional dynamics information on the osteointegration process. Twenty-five patients who underwent implantation operations for the application of intra- and extraoral prostheses were studied using technetium 99 m single photon emission computed tomographic (SPECT) procedures to evaluate osteointegration dynamics at 3 weeks, and 3, 6, 12, and 24 months. The study demonstrates that radiation emission peaks 3 weeks after surgery with the maximal bone remodeling activity and 6 months after surgery after the functional loading of the implants only in intraoral fixtures. High uptake past the eighth month after surgery has never been detected and must be considered abnormal. SPECT offers the possibility of obtaining a three-dimensional reconstruction of the photon emission of selected structures. The use of these nuclear medicine methods in addition to traditional-type radiological procedures introduces new possibilities, although still in the clinical experimentation phase, for early diagnosis and inserted implant prognosis.  相似文献   
6.
Carbon cloth reinforced RF (Resorcinol Formaldehyde) aerogel films have been produced with extremely high RC ratio (molar ratio of resorcinol to catalyst) or with no catalyst at all. The gels were subcritically dried. Carbon aerogel films were obtained by pyrolysis of the RF aerogel films. The structure of the composite porous films was investigated using infrared spectrometer, optical and electron scanning microscope. The IR measurements indicated that the bottom surface reflectance of the films is higher than the top surface. The microscopical pictures revealed that the bottom surface of the films has a denser structure than the top surface, and the presence of carbon cloth in the sol-gel process strongly influences the structure of the films. The carbon cloth fibers act as catalytic sites. The particles are more likely to form around the fibers instead of within the sol. This leads to a somewhat reduced specific surface area as was shown via N2 sorption and BET analysis.Using the 4-probe method the electrical conductivity of the carbon cloth reinforced carbon films was found to be higher than that of pure carbon aerogel films.  相似文献   
7.
OBJECTIVE: The role of steroid hormones in the control of human parturition has been a subject of debate. Activation of the fetal hypothalamic-pituitary-adrenal axis leading to an increase in plasma cortisol is followed by the onset of parturition in sheep. In contrast, androgens, specifically, dehydroepiandrosterone sulfate, have been implicated in the control of parturition in nonhuman primates. The purpose of this study was to determine the relationship between human fetal plasma cortisol and dehydroepiandrosterone sulfate and the onset of preterm labor in patients with preterm premature rupture of the membranes. STUDY DESIGN: Fetal blood sampling was performed in 51 patients with preterm premature rupture of membranes who were not in labor on admission. Amniotic fluid was cultured for aerobic and anaerobic bacteria and mycoplasmas. Corticosteroids had not been administered before fetal blood sampling. Cortisol and dehydroepiandrosterone sulfate were measured with sensitive and specific immunoassays. Analysis was conducted with nonparametric statistics and survival analysis. RESULTS: (1) Patients who went into spontaneous labor and delivered within 7 days of cordocentesis had a significantly higher median level of fetal plasma cortisol but not of dehydroepiandrosterone sulfate than those delivered after 7 days (for fetal plasma cortisol: median 8.35 [4.7 to 12.4] micrograms/dL vs median 4.75 [3.0 to 10.4] micrograms/dL, P <.0001; for fetal plasma dehydroepiandrosterone sulfate: median 154.4 [8.6 to 333.8] micrograms/dL vs median 194.6 [96.7 to 402.5] micrograms/dL, P =.09). (2) The cordocentesis-to-delivery interval was significantly shorter in patients with a fetal plasma cortisol value of >/=7 micrograms/dL (derived by receiver-operating characteristic curve analysis) than in those with fetal cortisol <7 micrograms/dL (median 49 [4 to 1849] hours vs median 325 [11 to 2590] hours, P <.001). (3) Fetal plasma cortisol, but not maternal cortisol, was an independent predictor of the duration of pregnancy after we adjusted for gestational age and the results of amniotic fluid culture (hazards ratio 2.9, P <.05). (4) There was a significant correlation between fetal plasma cortisol and fetal plasma interleukin-6 (r = 0.3, P <.05). (5) A strong relationship was found between the fetal plasma cortisol/dehydroepiandrosterone sulfate ratio and the interval to delivery (P <.005). CONCLUSION: An elevation in fetal plasma cortisol but not dehydroepiandrosterone sulfate was followed by the onset of spontaneous preterm labor in patients with preterm premature rupture of the membranes.  相似文献   
8.
Splenosis is the heterotopic autotransplantation of splenic tissue that usually follows traumatic splenectomy. The clinical significance of these splenic implants and the need for surgical removal is debatable. A case of a 35 year old woman, with post-traumatic splenectomy presenting with low abdominal pain and pelvic mass is reported. Laparoscopic removal of the pelvic splenic implants dispelled all complaints.  相似文献   
9.
OBJECTIVES: The objective of this study was to clarify the autonomic, central and peripheral nervous effects of vibrating-tool operation. METHODS: The ECG R-R interval variability (CVRR), including the C-CVHF, C-CVLF (two component CVs of the CVRR reflecting parasympathetic and sympathetic activities, respectively) and the power spectral densities (PSDHF and PSDLF) after autoregressive analysis, short-latency somatosensory evoked potentials (SSEP), distribution of nerve conduction velocities (DCV), and median and radial nerve conduction velocities (NCVs) were measured in 17 vibrating-tool operators and the same number of age-matched control subjects. Some of the operators complained of white finger even in summer as soon as they arrived at the cold workplace. DESIGN: The significance of the differences in neurophysiological data between the exposed and unexposed groups and the associations between these data in the former were investigated. RESULTS: The CVRR, C-CVHF and PSDHF were significantly lower in the vibrating-tool operators than in the matched controls. The N9-N13 interpeak latency of the SSEP, i.e., conduction time of the cervico-spinobulbar pathway, in the operators was significantly prolonged as compared with the controls; the faster velocities of the DCV and the NCVs were significantly slowed in the operators. The N9-N13 interpeak latency in the operators was significantly correlated with the C-CVHF. CONCLUSION: Complex stressors of local vibration, cold, noise and heavy work, seem to affect the cervico-spinobulbar, parasympathetic and peripheral nerve functions. Also, parasympathetic hypofunction may imply a consequence in brainstem pathology induced by cold exposure in addition to vibration.  相似文献   
10.
Highly insulating aerogel glazing for solar energy usage   总被引:1,自引:0,他引:1  
Granular silica aerogels have been integrated into highly-insulating translucent glazing. This work was performed within the large R&D project ISOTEG pursued by the ZAE Bayern. To avoid settlement of the granules, which often occurred in earlier glazing concepts and even caused destruction of the glazing, the granules were sandwiched between a double skin sheet made of PMMA. The sheet was mounted between two low-e coated glass panes. To optimize the thermal insulation, krypton was used as filling gas. This construction allows to achieve heat transfer coefficients of less than 0.4 W/(m2 K). Optimized granular layers provide high solar transmittance of 65% for a thickness of 20 mm. Thus a total solar energy transmittance of 35% for the whole glazing unit is achieved. The glazing has a thickness of less than 50 mm. Such aerogel glazings can be integrated into solar wall systems or used as lightscattering daylighting elements with vanishing energy losses over the heating period even for north facade integration. Optical and thermal properties of the developed granular aerogels as well as the thermal properties of the whole glazing unit are reported.  相似文献   
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