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971.
Double trisomies are a rare occurrence. We report the first case of a Down and Klinefelter's syndrome (48,XXY,+21) in a fetus that was prenatally diagnosed during the 15th week of pregnancy. Even though the nasal bone was present, and the color-Doppler study of the ductus venosus and the nuchal thickness were normal, the maternal serum test results indicated an increased risk of Down syndrome and consequentially a genetic amniocentesis was performed. A 48,XXY,+21 karyotype was observed and the patient decided to terminate the pregnancy. In this case, we did not find the typical ultrasound (US) signs that would have led us to the chromosomopathy; furthermore, we emphasize the advantages of using biochemical screening which, in our case, were crucial in arriving at the correct diagnosis. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
972.
Karen Hardy Stephen Buckley Matthew J. Collins Almudena Estalrrich Don Brothwell Les Copeland Antonio García-Tabernero Samuel García-Vargas Marco de la Rasilla Carles Lalueza-Fox Rosa Huguet Markus Bastir David Santamaría Marco Madella Julie Wilson ángel Fernández Cortés Antonio Rosas 《Die Naturwissenschaften》2012,99(8):617-626
Neanderthals disappeared sometime between 30,000 and 24,000?years ago. Until recently, Neanderthals were understood to have been predominantly meat-eaters; however, a growing body of evidence suggests their diet also included plants. We present the results of a study, in which sequential thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) were combined with morphological analysis of plant microfossils, to identify material entrapped in dental calculus from five Neanderthal individuals from the north Spanish site of El Sidrón. Our results provide the first molecular evidence for inhalation of wood-fire smoke and bitumen or oil shale and ingestion of a range of cooked plant foods. We also offer the first evidence for the use of medicinal plants by a Neanderthal individual. The varied use of plants that we have identified suggests that the Neanderthal occupants of El Sidrón had a sophisticated knowledge of their natural surroundings which included the ability to select and use certain plants. 相似文献
973.
Despite a rapidly improving fossil record, the reproductive biology of Mesozoic birds remains poorly known: only a handful of undisputed, isolated Cretaceous eggs (some containing embryonic remains) are known. We report here the first fossil evidence for a breeding colony of Mesozoic birds, preserved at the Late Cretaceous (Maastrichtian) Oarda de Jos (Od) site in the Sebe? area of Transylvania, Romania. A lens of calcareous mudstone with minimum dimensions of 80?cm length, 50?cm width and 20?cm depth contains thousands of tightly packed, morphologically homogenous eggshell fragments, seven near-complete eggs and neonatal and adult avialan skeletal elements. Eggshell forms 70–80?% of the matrix, and other fossils are entirely absent. The bones exhibit clear characters of the Cretaceous avialan clade Enantiornithes, and the eggshell morphology is also consistent with this identification. Both taphonomy and lithology show that the components of this lens were deposited in a single flood event, and we conclude that it represents the drowned remains of a larger enantiornithine breeding colony, swamped by rising water, washed a short distance and deposited in a shallow, low-energy pond. The same fate often befalls modern bird colonies. Such a large concentration of breeding birds suggests aquatic feeding in this species, augments our understanding of enantiornithine biology and shows that colonial nesting was not unique to crown birds. 相似文献
974.
A simulated landfill biocover microcosm consisting of a modifying ceramsite material and compost were investigated. Results show that the mixture can improve the material porosity and achieve a stable and highly efficient (100%) methane oxidation over an extended operating period. The diversity of the methanotrophic community in the microcosm was assessed. Type I methanotrophs were enhanced in the microcosm due to the increased air diffusion and distribution, whereas the microbial diversity and population density of type II methanotrophs were not significantly affected. Moreover, the type I methanotrophic community structure significantly varied with the reactor height, whereas that of type II methanotrophic communities did not exhibit a spatial variation. Phylogenetic analysis showed that type I methanotroph-based nested polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) resulted in the detection of eight different populations, most of which are related to Methylobacter sp., whereas that of type II resulted in the detection of nine different populations, most of which are related to Methylocystaceae. Methanotrophic community analysis also indicated that a number of new methanotrophic genera not closely related to any known methanotrophic populations were present. 相似文献
975.
Xiaoping Zhou Xiaoke Wang Lei Tong Hongxing Zhang Fei Lu Feixiang Zheng Peiqiang Hou Wenzhi Song Zhiyun Ouyang 《环境科学学报(英文版)》2012,24(12):2104-2112
The significant warming in urban environment caused by the combined effects of global warming and heat island has stimulated widely development of urban vegetations. However, it is less known of the climate feedback of urban lawn in warmed environment. Soil warming effect on net ecosystem exchange (NEE) of carbon dioxide during the transition period from winter to spring was investigated in a temperate urban lawn in Beijing, China. The NEE (negative for uptake) under soil warming treatment (temperature was about 5℃ higher than the ambient treatment as a control) was -0.71 μmol/(m2.sec), the ecosytem was a CO2 sink under soil warming treatment, the lawn ecosystem under the control was a CO2 source (0.13 μmol/(m2.sec)), indicating that the lawn ecosystem would provide a negative feedback to global warming. There was no significant effect of soil warming on nocturnal NEE (i.e., ecosystem respiration), although the soil temperature sensitivity (Q10) of ecosystem respiration under soil warming treatment was 3.86, much lower than that in the control (7.03). The CO2 uptake was significantly increased by soil warming treatment that was attributed to about 100% increase of α (apparent quantum yield) and Amax (maximum rate of photosynthesis). Our results indicated that the response of photosynthesis in urban lawn is much more sensitive to global warming than respiration in the transition period. 相似文献
976.
基于PCR-TGGE技术的餐厨垃圾厌氧消化微生物群落结构解析 总被引:1,自引:0,他引:1
为了解不同负荷下单相餐厨垃圾厌氧消化反应器内微生物群落结构演替特征,在单相厌氧消化反应器负荷为2.0~8.5kg·m-·3d-1(以VS计)的不同负荷条件下取样,运用16SrDNA的PCR-TGGE技术对反应器内微生物进行动态追踪.同时,运用Dice系统和NMDS软件对PCR-TGGE图谱进行分析.结果表明,负荷为4.0~6.0kg·m-·3d-1时,微生物群落结构变化不大;负荷为6.0~7.0kg·m-·3d-1时,微生物群落结构变化较为明显;负荷分别为7.0~8.0kg·m-·3d-1及8.5kg·m-·3d-1时,微生物群落结构变化最为明显.纵观整个过程,在餐厨垃圾厌氧消化反应器有机负荷在2.0~8.5kg·m-·3d-1下厌氧反应器内的微生物群落结构存在明显的阶段性演替;负荷为7.0kg·m-·3d-1时微生物群落结构的丰富度最好. 相似文献
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