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211.
Wayne H. Persutte B.S. R.D.M.S. Thaddeus W. Kurczynski K. Chaudhuri Roger R. Lenke Lee Woldenberg Ray A. Brinker 《黑龙江环境通报》1990,10(10):631-642
A case of fetal autosomal dominant microcephaly was prenatally diagnosed with ultrasonography in a woman with previously undiagnosed microcephaly. At the time of initial ultrasonographic assessment, the mother was identified to have a markedly small cranium, consistent with maternal microcephaly. The ultrasonographic examination showed the fetal head size to be four standard deviations below the mean for gestational age. Gesta-tional dating from the other biometric parameters and from the last menstrual period was consistent with 31 weeks' gestation. Neurosonographic evaluation of the fetus revealed no obvious structural abnormalities. Serial ultrasonographic examinations at 35 and 38 weeks' gestation showed no changes in the fetal head size. A 2·64 kg male fetus was delivered at term. Neonatal assessment showed the fetal head circumference to be less than the second percentile for gestational age. Neurologic assessment of the neonate with magnetic resonance imaging showed abnormal development of the brain, with small cerebellar and cerebral hemispheres, and pachygyria. These images are compared with the magnetic resonance images of the mother. Our findings of maternal and fetal microcephaly are consistent with autosomal dominant microcephaly. To our knowledge, this is the first report of the prenatal diagnosis of autosomal dominant microcephaly. 相似文献
212.
Herman E. Wyandt Ph.D. Thomas Maker Nancy L. Fisher Shivanand R. Patil Peter Osella Frederick W. Luthardt Charles Kawada Roger Williamson Aubrey Milunsky 《黑龙江环境通报》1990,10(9):569-574
We report three cases of amniocentesis in which mosaicism for trisomy 12 was detected in two or more independent cultures. The parents elected to terminate the pregnancy in all three cases. Follow-up studies in two of the cases confirmed the mosaicism in fetal tissues (in subcutaneous tissue in one case; in fetal lung in the other), but not in blood. No fetal anomalies were evident by ultrasound or at autopsy. These results along with other reported cases demonstrate the difficulty in counselling for mosaic trisomy 12. 相似文献
213.
Acomprehensive,standardized,andthematicallyappropriatemapofCentralAmericanvegetationandlandcovertypeswasdevelopedbyclassifyingtheremotesensedimagery(AVHRR)1km2 相似文献
214.
The goal of this study was to investigate the influence of one variable, natural organic matter, on residual gasoline saturation in sandy soils. Capillary pressure-saturation (Pc−S) relationships (air-gasoline) were determined for three physically-similar sandy soils, with different organic carbon contents (0.086%, 0.89% and 1.65%) and residual gasoline saturations were compared. Two initial moisture conditions, residual water saturation and air-dry, were evaluated. One soil type was packed to two different bulk densities. Visualization of the soils using cryo-scanning electron microscopy was performed to aid in better understanding the role of the organic matter in the soil. The results showed that soils with higher organic contents had higher residual gasoline saturations when starting with an initially air-dry soil. Increasing the bulk density of the same air-dried soil resulted in an increase in residual gasoline saturation. In the presence of a residual water saturation, however, residual gasoline saturations were virtually identical for the three soils and independent of bulk density; approximately 5–10 times lower than in soil that was initially air-dry. The presence of the residual water effectively coated the surface of the soil thereby reducing or eliminating gasoline/soil interactions. Some residual water may also be occupying very small pore spaces, making these locations inaccessible to the gasoline. 相似文献
215.
Juniper (Juniperus monosperma), a small-diameter underutilized material, has been studied as a lignocellulosic biosorbent for removing heavy metals from water. In this study, juniper wood was modified by sulfonation to enhance sorption capacity for cadmium in water. The origin of the enhancement was investigated by observing the sorption behaviors and the change in surface functional group concentrations. Cadmium sorption by all juniper wood biosorbents studied was fast and the sorption capacity decreased with decreasing pH, similar to results found for other biosorbents. Sulfonated juniper was found to have at least twice the sorption capacity for cadmium removal from water compared to that of untreated juniper, though the sorption capacity increased with increasing pH. A slight increase in carboxylate content after sulfonation was likely responsible for a small portion of the enhancement. Elemental analysis showed an increase in sulfur content after sulfonation. Diffuse reflectance infrared Fourier transform (DRIFT) spectra showed a decrease in the band at 1660 cm(-1) in the range of carbonyl groups as a result of sulfonation. This indicates that coniferaldehyde groups in the lignin of juniper wood corresponding to this band were substituted into sulfonic acid groups after sulfonation. This interpretation was supported by both the color forming reaction with phloroglucinol-hydrochloric acid and the reaction mechanisms from the acid sulfite pulping process. Consequently, the enhancement of cadmium sorption capacity of juniper wood by sulfonation mainly originated from the production of sulfonic acid groups, which are binding sites for heavy metals. 相似文献
216.
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218.
C. Roger 《Marine Biology》1973,18(4):317-320
Analysis of the fluctuations of the repletion index of stomachs over a 24 h period allowed us to establish the main features of the feeding behaviour for the most abundant species of euphausiids inhabiting the equatorial and south tropical Pacific Ocean. Although feeding activity never stops completely, its intensity shows usually a rhythm, revealed by a sinusoid-type curve of the repletion index. This rhythm, in most cases, is not synchronous with the day-night alternation; for several species, an increase of the feeding activity is evident as early as 14.00 hrs, i.e., long before the nocturnal ascent of animals toward the surface, when they are still concentrated in the 300 to 600 m water layer. By integrating the data for 9 species, it is shown that the search for food is, as a whole, most active by night (20.00 to 6.00 hrs) in the subsurface layers, but is also quite intense between 14.00 and 20.00 hrs in intermediate and deep layers (300 to 600 m). 相似文献
219.
Andrew S. Cohen Roger Bills Christine Z. Cocquyt A.G. Caljon 《Conservation biology》1993,7(3):667-677
220.
Low level liquid radioactive waste discharges from the Sellafield nuclear fuel reprocessing plant in north west England had
generated environmental inventories of about 3 × 1016 Bq of137Cs, 6.8 × 1014 Bq of239,240Pu and 8.9 × 1014 Bq of241Am by 1990. Most of the239,240Pu and241Am and about 10% of the137Cs has been retained in a deposit of fine marine sediment close to the discharge point. The quantities of radionuclides discharged
annually from Sellafield decreased by two orders of magnitude from the mid-1970s to 1990 but estimated critical group internal
and external exposure decreased by less than one order of magnitude over this period. This indicates that during the period
of reduced discharges, radionuclides already in the environment from previous releases continued to contribute to the critical
group exposure and highlights the need to understand processes controlling the environmental distribution of the radionuclides.
Redistribution of the contaminated marine sediment is potentially of major significance in this context, in particular if
it results in transport of radionuclides to intertidal areas, where contact with the human population is relatively likely.
A review is presented of published work relating to Sellafield waste radionuclides in Irish Sea sediments. Data on temporal
and spatial trends in radionuclide concentrations and activity ratios are collated from a number of sources to show that the
dominant mechanism of radionuclide supply to intertidal areas is by redistribution of the contaminated marine sediment. The
implications of this mechanism of supply for trends in critical group radiation exposure are considered. 相似文献