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101.
Predictive models, based on environmental and water quality variables, have been used to improve the timeliness and accuracy of recreational water quality assessments, but their effectiveness has not been studied in inland waters. Sampling at eight inland recreational lakes in Ohio was done in order to investigate using predictive models for Escherichia coli and to understand the links between E. coli concentrations, predictive variables, and pathogens. Based upon results from 21 beach sites, models were developed for 13 sites, and the most predictive variables were rainfall, wind direction and speed, turbidity, and water temperature. Models were not developed at sites where the E. coli standard was seldom exceeded. Models were validated at nine sites during an independent year. At three sites, the model resulted in increased correct responses, sensitivities, and specificities compared to use of the previous day''s E. coli concentration (the current method). Drought conditions during the validation year precluded being able to adequately assess model performance at most of the other sites. Cryptosporidium, adenovirus, eaeA (E. coli), ipaH (Shigella), and spvC (Salmonella) were found in at least 20% of samples collected for pathogens at five sites. The presence or absence of the three bacterial genes was related to some of the model variables but was not consistently related to E. coli concentrations. Predictive models were not effective at all inland lake sites; however, their use at two lakes with high swimmer densities will provide better estimates of public health risk than current methods and will be a valuable resource for beach managers and the public.  相似文献   
102.
Fossil footprints preserve the only direct evidence of the external foot morphologies and gaits of extinct hominin taxa. However, their interpretation requires an understanding of the complex interaction among foot anatomy, foot function, and soft sediment mechanics. We applied an experimental approach aimed at understanding how one measure of foot function, the distribution of plantar pressure, influences footprint topography.  相似文献   
103.
This study addresses how the human temporal bone develops the population-specific pattern of morphology observed among adults and at what point in ontogeny those patterns arise. Three-dimensional temporal bone shape was captured using 15 landmarks on ontogenetic series of specimens from seven modern human populations. Discriminant function analysis revealed that population-specific temporal bone morphology is evident early in ontogeny, with significant shape differences among many human populations apparent prior to the eruption of the first molar. As early as five years of age, temporal bone shape reflects population history and can be used to reliably sort populations, although those in closer geographic proximity and molecular affinity are more likely to be misclassified. The deviation of cold-adapted populations from this general pattern of congruence between temporal bone morphology and genetic distances, identified in previous work, was confirmed here in adult and subadult specimens, and was revealed to occur earlier in ontogeny than previously recognized. Significant differences exist between the ontogenetic trajectories of some pairs of populations, but not among others, and the angles of these trajectories do not reflect genetic relationships or final adult temporal bone size. Significant intrapopulation differences are evident early in ontogeny, with differences becoming amplified by divergent trajectories in some groups. These findings elucidate how the congruence between adult human temporal bone morphology and population history develops, and reveal that this pattern corresponds closely to that described previously for facial ontogeny.  相似文献   
104.
The enteric nervous system (ENS) is a vital part of the autonomic nervous system that regulates many gastrointestinal functions, including motility and secretion. All neurons and glia of the ENS arise from neural crest-derived cells that migrate into the gastrointestinal tract during embryonic development. It has been known for many years that a subpopulation of the enteric neural crest-derived cells expresses pan-neuronal markers at early stages of ENS development. Recent studies have demonstrated that some enteric neurons exhibit electrical activity from as early as E11.5 in the mouse, with further maturation of activity during embryonic and postnatal development. This article discusses the maturation of electrophysiological and morphological properties of enteric neurons, the formation of synapses and synaptic activity, and the influence of neural activity on ENS development.  相似文献   
105.
Hepatocyte nuclear factor 4α (HNF4α) regulates liver type fatty acid binding protein (L-FABP) gene expression. Conversely as shown herein, L-FABP structurally and functionally also interacts with HNF4α. Fluorescence resonance energy transfer (FRET) between Cy3-HNF4α (donor) and Cy5-L-FABP (acceptor) as well as FRET microscopy detected L-FABP in close proximity (∼80 Å) to HNF4α, binding with high affinity Kd ∼250–300 nM. Circular dichroism (CD) determined that the HNF4α/L-FABP interaction altered protein secondary structure. Finally, L-FABP potentiated transactivation of HNF4α in COS7 cells. Taken together, these data suggest that L-FABP provides a signaling path to HNF4α activation in the nucleus.  相似文献   
106.
The morphology of the teliospores of Puccinia smyrnii has been variously described as warted, or reticulate, or a combination of both patterns. Spores were examined by LM and SEM, and shown to be irregularly warted. The sequence of development of the spores was examined by TEM. Four phases of wall differentiation were recognised. The ornamentation results from a differential deposition of secondary wall components, which are concentrated into invaginations of the cytoplasm. The subsequent exsertion of these invaginations, and concomitant disappearance of the primary wall, reveal the irregular warts of the mature spore. This mode of ornament formation is compared with other rust spore forms, and contrasted with that already outlined for Puccinia chaerophylli, a truly reticulatespored Umbelliferous rust. Combined SEM and TEM observations suggest an explanation for the erroneous LM interpretations.  相似文献   
107.
The optimization of a potent and highly selective series of dual mTORC1 and mTORC2 inhibitors is described. An initial focus on improving cellular potency whilst maintaining or improving other key parameters, such as aqueous solubility and margins over hERG IC50, led to the discovery of the clinical candidate AZD8055 (14). Further optimization, particularly aimed at reducing the rate of metabolism in human hepatocyte incubations, resulted in the discovery of the clinical candidate AZD2014 (21).  相似文献   
108.
A novel series of indole/indazole-aminopyrimidines was designed and synthesized with an aim to achieve optimal potency and selectivity for the c-Jun kinase family or JNKs. Structure guided design was used to optimize the series resulting in a significant potency improvement. The best compound (17) has IC50 of 3 nM for JNK1 and 20 nM for JNK2, with greater than 40-fold selectivity against other kinases with good physicochemical and pharmacokinetic properties.  相似文献   
109.
A proteomics survey of human placental syncytiotrophoblast (ST) apical plasma membranes revealed peptides corresponding to flotillin-1 (FLOT1) and flotillin-2 (FLOT2). The flotillins belong to a class of lipid microdomain-associated integral membrane proteins that have been implicated in clathrin- and caveolar-independent endocytosis. In the present study, we characterized the expression of the flotillin proteins within the human placenta. FLOT1 and FLOT2 were coexpressed in placental lysates and BeWo human trophoblast cells. Immunofluorescence microscopy of first-trimester and term placentas revealed that both proteins were more prominent in villous endothelial cells and cytotrophoblasts (CTs) than the ST. Correspondingly, forskolin-induced fusion in BeWo cells resulted in a decrease in FLOT1 and FLOT2, suggesting that flotillin protein expression is reduced following trophoblast syncytialization. The flotillin proteins co-localized with a marker of fluid-phase pinocytosis, and knockdown of FLOT1 and/or FLOT2 expression resulted in decreased endocytosis of cholera toxin B subunit. We conclude that FLOT1 and FLOT2 are abundantly coexpressed in term villous placental CTs and endothelial cells, and in comparison, expression of these proteins in the ST is reduced. These findings suggest that flotillin-dependent endocytosis is unlikely to be a major pathway in the ST, but may be important in the CT and endothelium.  相似文献   
110.
Although mate choice by males does occur in nature, our understanding of its importance in driving evolutionary change remains limited compared with that for female mate choice. Recent theoretical models have shown that the evolution of male mate choice is more likely when individual variation in male mating effort and mating preferences exist and positively covary within populations. However, relatively little is known about the nature of such variation and its maintenance within natural populations. Here, using the Trinidadian guppy (Poecilia reticulata) as a model study system, we report that mating effort and mating preferences in males, based on female body length (a strong correlate of fecundity), positively covary and are significantly variable among subjects. Individual males are thus consistent, but not unanimous, in their mate choice. Both individual mating effort (including courtship effort) and mating preference were significantly repeatable. These novel findings support the assumptions and predictions of recent evolutionary models of male mate choice, and are consistent with the presence of additive genetic variation for male mate choice based on female size in our study population and thus with the opportunity for selection and further evolution of large female body size through male mate choice.  相似文献   
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