Fetal magnetic resonance imaging (MRI) of ischemic brain injury

The aim of the present study was to demonstrate the usefulness of fetal magnetic resonance imaging (MRI) in ischemic brain injury. We report seven cases of fetal brain ischemia prenatally suspected on ultrasound (US) and confirmed by fetal MRI. Sonographic abnormalities included ventricular dilatation (n=3), microcephaly (n=1), twin pregnancy with in utero death of a twin and suspected cerebral lesion in the surviving co-twin (n=3). MRI was performed with a 1.0 T unit using half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences between 28 and 35 weeks of gestation. US and MRI images were compared with pathologic findings or postnatal imaging. MRI diagnosed hydranencephaly (n=1), porencephaly (n=2), multicystic encephalomalacia (n=2), unilateral capsular ischemia (n=1), corpus callosum and cerebral atrophy (n=1). In comparison with US, visualization of fetal brain anomalies was superior with MRI. The present cases demonstrate that MRI is a valuable complementary means of investigation when a brain pathology is discovered or suspected during prenatal US. Copyright © 2001 John Wiley & Sons, Ltd.     

Predicting phosphorus losses with the PLEASE model on a local scale in Denmark and the Netherlands

To reduce losses from agricultural soils to surface water, mitigation options have to be implemented as a local scale. For a cost-effective implementation of these measures, an instrument to identify critical areas for P leaching is indispensable. In many countries, P-index methods are used to identify areas as risk for P losses to surface water. In flat areas, where losses by leaching are dominant, these methods have their limitations because leaching is often not described in detail, PLEASE, is a simple mechanistic model designed to stimulate P Losses by leaching at the field scale using a limited amount of local field data. In this study, PLEASE, was applied to 17 lowland sites in Denmark and 14 lowland sites in the Netherlands. Results show that the simple model simulated measured fluxes and concentrations in water from pipe drains, suction cups, and groundwater quite well. The modeling efficiency ranged from 0.92 for modeling total-P fluxes to 0.36 fr modeling concentrations in groundwater. Poor results were obtained for heavy clay soils and eutrophic peat soils, where fluxes and concentration were strongly underestimated by the model. The poot performance for the heavy clay soil can be explained by the transport of P through macropores to the drain pipes and the underestimation of overland flow on this heavy-textured soil. In the eutrophic peat soils, fluxes were underestimated due to the release of P from deep soil layers.     

Incubation time, functional litter diversity, and habitat characteristics predict litter-mixing effects on decomposition

Plant diversity influences many fundamental ecosystem functions, including carbon and nutrient dynamics, during litter breakdown. Mixing different litter species causes litter mixtures to lose mass at different rates than expected from component species incubated in isolation. Such nonadditive litter-mixing effects on breakdown processes often occur idiosyncratically because their direction and magnitude change with incubation time, litter species composition, and ecosystem characteristics. Taking advantage of results from 18 litter mixture experiments in streams, we examined whether the direction and magnitude of nonadditive mixing effects are randomly determined. Across 171 tested litter mixtures and 510 incubation time-by-mixture combinations, nonadditive effects on breakdown were common and on average resulted in slightly faster decomposition than expected. In addition, we found that the magnitude of nonadditive effects and the relative balance of positive and negative responses in mixtures change predictably over time, and both were related to an index of functional litter diversity and selected environmental characteristics. Based on these, it should be expected that nonadditive effects are stronger for litter mixtures made of functionally dissimilar species especially in smaller streams. Our findings demonstrate that effects of litter diversity on plant mixture breakdown are more predictable than generally thought. We further argue that the consequences of current worldwide homogenization in the composition of plant traits on carbon and nutrient dynamics could be better inferred from long-duration experiments that manipulate both functional litter diversity and ecosystem characteristics in "hotspots of biodiversity effects," such as small streams.     

溶剂萃取法再生废机油的研究

用溶剂萃取-白土精制法对4种废机油进行了再生研究,萃取过程剂油质量比为3∶1,萃取温度为60℃,减压蒸馏回收溶剂。白土精制过程中白土质量为油质量的10%,精制温度为185℃。精制后4种废机油的密度、凝点、黏度、闪点、酸值等都有不同程度的改善。     

Optimizing Human Intestinal Enteroids for Environmental Monitoring of Human Norovirus

Human noroviruses (HuNoV) are the leading cause of gastrointestinal illness and environmental monitoring is crucial to prevent HuNoV outbreaks. The recent development of a HuNoV cell culture assay in human intestinal enteroids (HIEs) has enabled detection of infectious HuNoV. However, this complex approach requires adaptation of HIEs to facilitate HuNoV replication from environmental matrixes. Integrating data from 200 experiments, we examined six variables: HIE age, HIE basement membrane compounds (BMC), HuNoV inoculum processing, HuNoV inoculum volume, treatment of data below limit of detection (LOD), and cutoff criteria for determining positive HuNoV growth. We infected HIEs with HuNoV GII.4 Sydney positive stool and determined 1.4 × 10³ genome equivalents per HIE well were required for HuNoV replication. HIE age had minimal effect on assay outcomes. LOD replacement and cutoff affected data interpretation, with lower values resulting in higher estimated HuNoV detection. Higher inoculum volumes lead to minimal decreases in HuNoV growth, with an optimal volume of 250uL facilitating capture of low concentrations of HuNoVs present in environmental isolates. Processing of HuNoV inoculum is valuable for disinfection studies and concentrating samples but is not necessary for all HIE applications. This work enhances the HuNoV HIE cell culture approach for environmental monitoring. Future HIE research should report cell age as days of growth and should clearly describe BMC choice, LOD handling, and positive cutoff.

     

Similar is not the same: Social calls of conspecifics are more effective in attracting wild bats to day roosts than those of other bat species

Many bat species regularly need to find new day roosts as they require numerous shelters each breeding season. It has been shown that bats exchange information about roosts among colony members, and use echolocation and social calls of conspecifics in order to find roosts. However, it is unclear if wild bats discriminate between social calls of conspecifics and other bat species while searching for roosts. Furthermore, the extent that bats are attracted to potential roosts by each of these two call types is unknown. We present a field experiment showing that social calls of conspecifics and other bat species both attract bats to roosts. During two summers, we played back social calls of Bechstein’s bats (Myotis bechsteinii) and Natterer’s bats (Myotis nattereri) from different bat boxes that can serve as roosts for these species. All experimental bat boxes were monitored with infrared video to identify the approaching bat species. Three species (M. bechsteinii, M. nattereri, and Plecotus auritus) approached the boxes significantly more often during nights when bat calls were played compared to nights without playbacks. Bechstein’s bats and Natterer’s bats were both more attracted to social calls of conspecifics than of the other species, whereas P. auritus did not discriminate between calls of either Myotis species. Only Bechstein’s bats entered experimental boxes and only at times when calls from conspecifics were played. Our findings show that wild bats discriminate between social calls of conspecifics and other bat species although they respond to both call types when searching for new roosts.     

Measuring facial symmetry in the wild: a case study in Olive Baboons (Papio anubis)

Individuals under stress and those of intrinsically low quality may have insufficient resources to invest in developing equally on both sides. Such individuals may thus display higher levels of fluctuating asymmetry (FA)—small, random departures from perfect bilateral symmetry. These small deviations from symmetry are often less than 1 % of trait size, similar to variation in symmetry generated by measurement error. Studies regarding FA must thoroughly assess measurement error if reliable conclusions regarding FA and fitness parameters are to be drawn. Although many studies regarding facial symmetry in humans have been conducted, few have been carried out on non-human primates. The primary aim of this study was to assess whether facial FA in a non-human primate, the olive baboon (Papio anubis) can be reliably measured from digital photographs. Facial FA was measured in three sets of bilaterally symmetrical landmarks from digital images of 35 olive baboons at Gashaka-Gumti National Park, Nigeria. Measurement error was found to be low indicating a high level of reliability based on comparisons of values from two photos of the same individual (r?=?0.85). Measurement error was found to be related to the size of the face. This suggests that orientation error increases in large faces and could potentially influence FA scores. These findings highlight the need for FA studies to measure and control error caused by orientation and position of subjects if FA is to be of utility to behavioural ecology and conservation (e.g. if FA reflects whether individuals in a population are suffering from environmental or genetic stress).