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11.
An association between various abnormal mid-trimester maternal serum analyte values and adverse perinatal outcome has been reported. From an original sample of 14 857 women, we observed five women who were ‘screen-positive’ for both neural tube defects [maternal serum alpha-fetoprotein (MSAFP) ≥2·5 multiples of the median] and Down syndrome [risk ≥1/274 using MSAFP, maternal serum unconjugated oestriol (MSuE3), maternal serum human chorionic gonadotropin (MShCG), and maternal age]. The four patients who elected to undergo amniocentesis all demonstrated both normal karyotype and normal amniotic fluid AFP levels. All five cases were associated with intrauterine growth retardation (IUGR) and abnormal pregnancy outcomes. Two cases exhibiting severe IUGR on ultrasound examination were terminated at 19·1 and 21·2 weeks, respectively; the former also exhibited fetal calcifications and positive maternal serology for toxoplasmosis. In another case, fetal demise occurred at 36 weeks' gestation in a patient who had been treated for syphilis in the second trimester. Neither infection was confirmed in fetal tissue studies. Though resulting in live births, the remaining two cases required operative deliveries; emergency Caesarean sections for fetal distress were performed at 38 and 32 weeks, respectively, the latter case being associated with severe pre-eclampsia. We conclude that elevated mid-trimester MSAFP levels concurrent with maternal serum analyte values associated with increased risk for fetal Down syndrome may presage a poor perinatal outcome, particularly IUGR and possibly congenital infection.  相似文献   
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Measurement of personal exposure to ambient level particulate concentrations is often extremely difficult because of a lack of personal exposure monitors capable of collecting measurable quantities within a meaningful sampling period. A new personal exposure monitor for two fractions of inhalable particulates (i.e., the 3–15 μm aerodynamic diameter and the < 3 μm or respirable fraction) has been developed and characterized. This monitor is capable of collecting a sample of each fraction that is quantifiable with ambient concentrations of inhalable/respirable particulates as low as 25 μg/m3 in a 24-h sampling period. Wind tunnel tests have been made on the particulate personal exposure monitor to determine sampling efficiency as a function of relative wind speed and orientation with respect to the sampler.  相似文献   
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Riftia pachyptila Jones, 1981, lives in association with a chemoautotrophic, sulfide-oxidizing -Proteobacterium that occurs in a specialized organ, the trophosome. Ultrastructurally different bacterial subpopulations occur in different regions of the trophosome lobules (central rods, median small cocci, peripheral large cocci) and contain vesicles, which have been proposed to be sites of elemental sulfur storage. Differently colored trophosomes have been suggested to reflect different amounts of elemental sulfur in the tissue. In this study, the presence of elemental sulfur (S0) was confirmed in the vesicles of the symbionts of R. pachyptila by electron energy loss spectrography (EELS). The proportion of (two-dimensional) area occupied by sulfur vesicles in the cells was found to be strongly correlated with trophosome color, both in individuals with uniformly colored trophosomes and individuals that exhibited a gradual color change along the length of their trophosomes. Elemental sulfur content was highly variable between individuals from a single collection, suggesting a high degree of microhabitat heterogeneity within vestimentiferan aggregations.Communicated by O. Kinne, Oldendorf/Luhe  相似文献   
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Calcification rate in the coral Acropora cervicornis was reduced significantly when exposed for 24 h to 100-ppm kaolin, but was unchanged in corals exposed to 50-ppm kaolin. Calcification rate returned to control levels during a 48-h recovery period. Most free amino acids (FAA) in the FAA pool decreased significantly in corals exposed to 100-ppm kaolin, but were unchanged in corals exposed to 50-ppm kaolin. After a 48-h recovery period, the FAA pool remained considerably below control levels in the 100-ppm exposed corals and dropped below control levels in the 50-ppm exposed corals. Calcification rate dropped less and later during the exposure period in the growing tip than in sections further down the stalk. The reduction in FAA pool size was considerably larger in the growing tip than further down the stalk. Soluble protein concentration remained unchanged during both exposure and recovery. The data are consistent with the interpretation that turbidity not only causes a decrease in photosynthetic rate and the synthesis of small molecules, but also causes a large increase in the utilization of stored organic molecules for such metabolically costly processes as mucus production and sediment removal.  相似文献   
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Avifaunal Collapse in West African Forest Fragments   总被引:7,自引:0,他引:7  
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Enteric viruses are often present in low numbers in various water matrices. Virus sampling therefore involves multiple concentration steps to condense large samples down to small volumes for detection by cell culture or molecular assays. The NanoCeram® Virus Sampler has been demonstrated to be effective for the recovery of viruses from tap water, surface waters, and seawater. The goal of this study was to evaluate a new method using NanoCeram® filters for the recovery of poliovirus 1 (PV-1) from treated wastewater. Activated sludge effluent samples were spiked with PV-1 and concentrated in side-by-side tests by two methods: (1) NanoCeram® filtration, elution with sodium polyphosphate buffer, secondary concentration via centrifugal ultrafiltration; and (2) 1MDS filtration, elution with beef extract, secondary concentration via organic flocculation. The virus retention and elution efficiencies did not differ significantly between the two methods. In contrast, the secondary concentrate volume was smaller for the NanoCeram® method (8.4 vs. 30 mL) and the secondary concentration efficiencies were different between the two methods with 98 % for centrifugal ultrafiltration (NanoCeram®) and 45 % for organic flocculation (1MDS). The overall method efficiencies were significantly different (P ≤ 0.05) with the NanoCeram® method yielding a 57 % and the 1MDS a 23 % virus recovery. In addition, there appeared to be less interference with viral detection via polymerase chain reaction with the NanoCeram® concentrates. This NanoCeram® method therefore is able to efficiently recover PV-1 from large volumes of wastewater and may serve as an inexpensive alternative to the standard 1MDS filter method for such applications.  相似文献   
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Environmental Science and Pollution Research - Considering the prevailing wave of global warming and other environmental challenges, which can be attributed to increasing environmental pollution as...  相似文献   
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Environmental Science and Pollution Research - The study determines the development of the sustainability reporting domain using a dataset of publications extracted from the Web of Science (WoS)...  相似文献   
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