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排序方式: 共有106条查询结果,搜索用时 15 毫秒
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Improved wetland remote sensing in Yellowstone National Park using classification trees to combine TM imagery and ancillary environmental data 总被引:6,自引:0,他引:6
The U.S. Fish and Wildlife Service uses the term palustrine wetland to describe vegetated wetlands traditionally identified as marsh, bog, fen, swamp, or wet meadow. Landsat TM imagery was combined with image texture and ancillary environmental data to model probabilities of palustrine wetland occurrence in Yellowstone National Park using classification trees. Model training and test locations were identified from National Wetlands Inventory maps, and classification trees were built for seven years spanning a range of annual precipitation. At a coarse level, palustrine wetland was separated from upland. At a finer level, five palustrine wetland types were discriminated: aquatic bed (PAB), emergent (PEM), forested (PFO), scrub-shrub (PSS), and unconsolidated shore (PUS). TM-derived variables alone were relatively accurate at separating wetland from upland, but model error rates dropped incrementally as image texture, DEM-derived terrain variables, and other ancillary GIS layers were added. For classification trees making use of all available predictors, average overall test error rates were 7.8% for palustrine wetland/upland models and 17.0% for palustrine wetland type models, with consistent accuracies across years. However, models were prone to wetland over-prediction. While the predominant PEM class was classified with omission and commission error rates less than 14%, we had difficulty identifying the PAB and PSS classes. Ancillary vegetation information greatly improved PSS classification and moderately improved PFO discrimination. Association with geothermal areas distinguished PUS wetlands. Wetland over-prediction was exacerbated by class imbalance in likely combination with spatial and spectral limitations of the TM sensor. Wetland probability surfaces may be more informative than hard classification, and appear to respond to climate-driven wetland variability. The developed method is portable, relatively easy to implement, and should be applicable in other settings and over larger extents. 相似文献
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Liana Sargsyan Austin R. Swisher Alisa P. Hetrick Hongzhe Li 《International journal of molecular sciences》2022,23(13)
Combining aminoglycosides and loop diuretics often serves as an effective ototoxic approach to deafen experimental animals. The treatment results in rapid hair cell loss with extended macrophage presence in the cochlea, creating a sterile inflammatory environment. Although the early recruitment of macrophages is typically neuroprotective, the delay in the resolution of macrophage activity can be a complication if the damaged cochlea is used as a model to study subsequent therapeutic strategies. Here, we applied a high dose combination of systemic gentamicin and furosemide in C57 BL/6 and CBA/CaJ mice and studied the ototoxic consequences in the cochlea, including hair cell survival, ribbon synaptic integrity, and macrophage activation up to 15-day posttreatment. The activity of macrophages in the basilar membrane was correlated to the severity of cochlear damage, particularly the hair cell damage. Comparatively, C57 BL/6 cochleae were more vulnerable to the ototoxic challenge with escalated macrophage activation. In addition, the ribbon synaptic deterioration was disproportionately limited when compared to the degree of outer hair cell loss in CBA/CaJ mice. The innate and differential otoprotection in CBA/CaJ mice appears to be associated with the rapid activation of cochlear macrophages and a certain level of synaptogenesis after the combined gentamicin and furosemide treatment. 相似文献
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Vadym Burchak Fritz Koch Leonard Siebler Sonja Haase Verena K. Horner Xenia Kempter G. Bjrn Stark Ute Schepers Alisa Grimm Stefan Zimmermann Peter Koltay Sandra Strassburg Günter Finkenzeller Filip Simunovic Florian Lampert 《International journal of molecular sciences》2022,23(14)
Introduction: Three-dimensional bioprinting can be considered as an advancement of the classical tissue engineering concept. For bioprinting, cells have to be dispersed in hydrogels. Recently, a novel semi-synthetic thiolene hydrogel system based on norbornene-functionalized gelatin (GelNB) and thiolated gelatin (GelS) was described that resulted in the photoclick hydrogel GelNB/GelS. In this study, we evaluated the printability and biocompatibility of this hydrogel system towards adipose-tissue-derived mesenchymal stem cells (ASCs). Methods: GelNB/GelS was synthesized with three different crosslinking densities (low, medium and high), resulting in different mechanical properties with moduli of elasticity between 206 Pa and 1383 Pa. These hydrogels were tested for their biocompatibility towards ASCs in terms of their viability, proliferation and differentiation. The extrusion-based bioprinting of ASCs in GelNB/GelS-high was performed to manufacture three-dimensional cubic constructs. Results: All three hydrogels supported the viability, proliferation and chondrogenic differentiation of ASCs to a similar extent. The adipogenic differentiation of ASCs was better supported by the softer hydrogel (GelNB/GelS-low), whereas the osteogenic differentiation was more pronounced in the harder hydrogel (GelNB/GelS-high), indicating that the differentiation fate of ASCs can be influenced via the adaption of the mechanical properties of the GelNB/GelS system. After the ex vivo chondrogenic differentiation and subcutaneous implantation of the bioprinted construct into immunocompromised mice, the production of negatively charged sulfated proteoglycans could be observed with only minimal inflammatory signs in the implanted material. Conclusions: Our results indicate that the GelNB/GelS hydrogels are very well suited for the bioprinting of ASCs and may represent attractive hydrogels for subsequent in vivo tissue engineering applications. 相似文献
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Charles E. Carraher Jr. Michael R. Roner Anthony G. Campbell Alisa Moric-Johnson Lindsey Miller Paul Slawek 《国际聚合物材料杂志》2018,67(8):469-479
Polyesters were formed from the reaction of the salt of camphoric acid and Group IVB metallocene dichlorides using the interfacial polycondenzation process. The polyesters were formed in good yields with moderate chain lengths. Fourier transform infrared spectroscopy shows bands characteristic of the presence of both reactants with new bands characteristic of the formation of the M?O and M–O(CO) linkage present. The polymers largely exist in a bridging geometry of the carbonyl groups about the metal atom. Nuclear magnetic resonance shows the presence of bands derived from both reactants. Matrix-assisted laser desorption/ionization mass spectroscopy shows ion fragments to three units for the polymers with isotopic abundance characteristic of the presence of metal atoms in the ion fragment clusters. All the polymers exhibit good ability to inhibit all the tested cancer cell lines but the zironocene and hafnocene polymers exhibit especially good inhibition of the tested cancer cell lines that included two pancreatic cancer cell lines. They represent a potential new group of anticancer drugs. 相似文献
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Alisa Schnellbaecher Anton Lindig Maxime Le Mignon Tim Hofmann Brit Pardon Stephanie Bellmaine Aline Zimmer 《International journal of molecular sciences》2021,22(12)
Biomanufacturing processes may be optimized by storing cell culture media at room temperature, but this is currently limited by their instability and change in color upon long-term storage. This study demonstrates that one of the critical contributing factors toward media browning is tryptophan. LC-MS technology was utilized to identify tryptophan degradation products, which are likely formed primarily from oxidation reactions. Several of the identified compounds were shown to contribute significantly to color in solutions but also to exhibit toxicity against CHO cells. A cell-culture-compatible antioxidant, a-ketoglutaric acid, was found to be an efficient cell culture media additive for stabilizing components against degradation, inhibiting the browning of media formulations, and decreasing ammonia production, thus providing a viable method for developing room-temperature stable cell culture media. 相似文献
8.
Davis Hasker P.; Cohen Alisa; Gandy Michele; Colombo Paul; VanDusseldorp Gene; Simolke Neil; Romano Jane 《Canadian Metallurgical Quarterly》1990,104(2):288
The effects of age on implicit memory were assessed in elderly and young adults using 2 priming procedures. Subjects also completed the Wechsler Adult Intelligence Scale—Revised (WAIS—R), 3 tests to assess frontal lobe function, and 2 recall and 2 recognition tests of explicit memory. In Experiment 1, subjects were exposed to the low-frequency member of a homophone pair in a test purported to assess general knowledge. Subsequently, subjects completed a spelling test that contained the previously presented homophones to assess priming. Young subjects demonstrated priming (p?p?p? 相似文献
9.
Cytosine arabinoside (Ara-C) has been used in the treatment of acute myeloid leukemia. However, rapid deamination reduces its effectiveness. Polymeric matrices containing ara-C were prepared in polyether polyurethane copolymer to form a protective, supply of ara-C. Release studies from these devices showed linear relationships between Q, the amount release per unit area, versus the square root of time. Burst effects were predominant at higher loading doses. The diffusivity values indicated that enough drug could pass through the polymer for the combination to have potential application as implants in cancer therapy. 相似文献
10.
Intimates can rely on a number of strategies to protect their relationships from potential threats. In the present article, the authors investigate a new strategy: to discount flattering comments received from an attractive alternative to a dating partner by making a situational attribution. However, the authors did not expect everyone to adopt this strategy, as not everyone is likely sufficiently motivated to override both the tendencies to make dispositional attributions and to accept positive feedback from others. Dating and single participants were informed that an attractive alternative's positive impression of them had been made freely or under constraint. As expected, dating participants in the constraint condition were less likely than were those in the no-constraint condition to believe that the alternative's impression of them was genuine. In contrast, single participants believed that the confederate's impression of them was genuine, irrespective of their experimental condition. Self-esteem further moderated this effect. As hypothesised, only dating participants with low self-esteem were sufficiently motivated to recognise the situational constraint and discount the positive feedback. High self-esteem daters who were less inclined to discount the positive feedback instead protected their relationships by devaluing the alternative's attractiveness compared to singles. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献