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131.
The variation of risk estimates in second trimester maternal serum screening for Down's syndrome has been shown to be considerable in quality control schemes, i.e. UKNEQAS. We studied the biological variation of risk estimates in 16 women through pregnancy. The maternal serum markers alpha-fetoprotein (AFP), human chorionic gonadotrophin (hCG), unconjugated estriol (uE3) and β-hCG were determined six times during late first to late second trimester, and the associated likelihood ratios for Down syndrome were calculated. The interpersonal variation of markers, as well as that of the likelihood ratio, was much greater than the intrapersonal variation. The average intrapersonal standard deviation (SD) of the triple test log likelihood ratio was 0.2291, corresponding to a central 95-percentile interval 0.36–2.81 of the likelihood ratio. The interpersonal SD of the log likelihood ratio was 0.5482, corresponding to a central 95-percentile interval 0.08–11.87 of the likelihood ratio. The large difference between the intra- and interpersonal variation makes it unlikely that biological variation through pregnancy is a major contributor to the variation of risk estimates obtained several times in the same pregnancy. Rather, improvements in analytical quality and laboratory management must be expected to result in reduced variation and, in consequence, better performance of screening. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
132.
W. Kutzelnigg R. Hoppe W. Stoll L. Horner M. J. S. Dewar U. Hofmann H. Ruschig G. Möllenstedt F. Lynen Imogen Rüsse L. Jaenicke H. Autrum W. Kreutz H. F. Linskens J. Reinert W. Rüdiger D. Claus E. Thenius J. Jacobs W. Wickler K. Keil G. Müller R. Lüst G. L. Krol K. Senghas H. Elsässer 《Die Naturwissenschaften》1969,56(3):147-152
133.
Claus Nissen A. v. Wacek Karl Freudenberg Hans Stille Walter Gross 《Die Naturwissenschaften》1939,27(31):535-536
134.
Bart De Keersmaecker Hilde Van Esch Dominique Van Schoubroeck Filip Claus Philippe Moerman Luc De Catte 《黑龙江环境通报》2013,33(3):292-295
We report the prenatal sonographic detection of a fetus with megalencephaly, polymicrogyria, postaxial polydactyly and hydrocephaly. Only 14 patients have been reported in the literature so far, all but one were diagnosed postnatally. The polymicrogyria in the frontoparietal lobe was confirmed by prenatal magnetic resonance imaging. Additionally, a hypoplastic thymus as seen in a 22q11 deletion was present. Although polymicrogyria along with pre-axial polydactyly has been described in 22q11 deletion, the diagnosis of Di George syndrome was ruled out. The etiology of megalencephaly, polymicrogyria, postaxial polydactyly and hydrocephaly has not been revealed yet. A dominant as well as recessive inheritance has been suggested. © 2013 John Wiley & Sons, Ltd. 相似文献
135.
136.
Fu-Lin Evelyn Chu Eric D. Lund Paul R. Littreal Kate E. Ruck Ellen Harvey Jean-René Le Coz Yanic Marty Jeanne Moal Philippe Soudant 《Marine Biology》2009,156(2):155-169
The kinetics and efficiency of sterol production and bioconversion of phytosterols in two heterotrophic protists Oxyrrhis marina and Gyrodinium dominans were examined by feeding them two different algal species (Rhodomonas salina and Dunaliella tertiolecta) differing in sterol profiles. R. salina contains predominantly brassicasterol (≅99%) and <2% cholesterol. The major sterols in D. tertiolecta are ergosterol (45–49%), 7-dehydroporiferasterol (29–31%) and fungisterol (21–26%). O. marina fed R. salina metabolized dietary brassicasterol to produce 22-dehydrocholesterol and cholesterol. O. marina fed D. tertiolecta metabolized dietary sterols to produce cholesterol, 22-dehydrocholesterol, brassicasterol and stigmasterol. G. dominans fed either R. salina or D. tertiolecta metabolized dietary sterols to make cholesterol, brassicasterol and a series of unknown sterols. When protists were fed R. salina, which contains cholesterol, the levels of cholesterol were increased to a magnitude of nearly 5- to 30-fold at the phytoplankton-heterotrophic
protist interface, equivalent to a production of 172.5 ± 16.2 and 987.7 ± 377.7 ng cholesterol per mg R. salina carbon consumed by O. marina and G. dominans, respectively. When protists were fed D. tertiolecta, which contains no cholesterol, a net production of cholesterol by the protists ranged from 123.2 ± 30.6 to 871.8 ± 130.8 ng
per mg algal C consumed. Cholesterol is not only the dominant sterol, but a critical precursor for many physiologically functional
biochemicals in higher animal. As intermediates, these heterotrophic protists increase the amount of cholesterol at the phytoplankton–zooplankton
interface available to higher trophic levels relative to zooplankton feeding on algae directly. 相似文献
137.
138.
139.
Steven J. Wright Evelyn Habit Sara Adlerstein Oscar Parra Jeremy D. Semrau 《Sustainability Science》2009,4(1):29-36
A course for upper division undergraduate students was developed in response to a request for a cross-disciplinary course
in environmental sustainability with an emphasis on an international issue. The topic selected for the course focused on the
energy needs for Chile and a proposal for five hydropower projects on the Baker and Pascua Rivers in the Patagonia area. Collaborations
between the University of Michigan (USA) and the University of Concepción (Chile) to develop the course led to a plan to offer
a parallel course at both universities, with the students of both courses participating in a site visit to Patagonia. The
courses were structured to enhance learning through interdisciplinary team-based activities. The courses were taught in a
seminar format, with invited lecturers to provide background information on technical, environmental, economic, social, and
political issues surrounding hydropower development in general and the proposed projects in particular. The students combined
this information with insights obtained during the site visit to prepare a variety of course products, notably an assessment
of the concerns of the various affected stakeholder groups. Assessment of the course outcomes is discussed. 相似文献
140.
Hooper HL Jurkschat K Morgan AJ Bailey J Lawlor AJ Spurgeon DJ Svendsen C 《Environment international》2011,37(6):1111-1117
Manufactured nanoparticles (NPs) are increasingly being used in a range of consumer products and are already entering the environment. NP ZnO is one of the most widely used and potentially toxic NPs in aquatic exposures. It is likely that ZnO nanoparticles will also be bioavailable to soil organisms, studies on ZnO NP toxicity in a soil matrix are lacking. We exposed the earthworm Eisenia veneta to uncoated NP ZnO (<100 nm) dosed to soil and food at 250 and 750 mg Zn kg(-1) for 21 d. Concurrent exposures of equivalent ionic Zn were conducted with ZnCl(2) and for both forms effects on life history traits, immune activity and Zn body concentrations were compared. Despite slightly higher measured body concentrations, NP ZnO generally had less impact than ZnCl(2) on measured traits. At 750 mg Zn kg(-1), reproduction declined by 50% when exposed to NP ZnO but was almost completely inhibited by ZnCl(2). Similarly, immune activity was unaffected by NP ZnO but was suppressed by 20% when exposed to ZnCl(2). Scanning electron microscopy analysis of worm tissues following 24h aqueous exposure showed the presence of ZnO particles suggesting that NPs can be taken up in particulate form. This may explain the reduced effects at similar body concentrations seen in the soil study. Our findings suggest that risk assessments do not need to go beyond considering the metal component of NP ZnO in soils at least for the larger size uncoated particles considered here. 相似文献