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The breast can be considered conceptually as a cone. This article compares and contrasts short-scar breast reduction techniques with inverted T techniques using the cone model. Four issues are examined-the base of the breast, breast projection, the inframammary fold, and the pedicle. The short-scar techniques focus on reshaping the breast parenchyma, and skin redraping occurs secondarily. Application of this model suggests that these techniques have the advantage of better projection and greater longevity. These techniques seldom give a square shape and are better at dealing with upper pole deficiency. However, the ability of the skin to redrape is the limiting factor; hence, results are less predictable with large-volume breast reductions. The emphasis of this article is on increasing the understanding of the mechanics of breast reduction. It is this factor that will enable appropriate selection of a particular technique. 相似文献
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Firn J Moore JL MacDougall AS Borer ET Seabloom EW HilleRisLambers J Harpole WS Cleland EE Brown CS Knops JM Prober SM Pyke DA Farrell KA Bakker JD O'Halloran LR Adler PB Collins SL D'Antonio CM Crawley MJ Wolkovich EM La Pierre KJ Melbourne BA Hautier Y Morgan JW Leakey AD Kay A McCulley R Davies KF Stevens CJ Chu CJ Holl KD Klein JA Fay PA Hagenah N Kirkman KP Buckley YM 《Ecology letters》2011,14(3):274-281
Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at 39 sites, within eight countries, revealed that species abundances were similar at native (home) and introduced (away) sites - grass species were generally abundant home and away, while forbs were low in abundance, but more abundant at home. Sites with six or more of these species had similar community abundance hierarchies, suggesting that suites of introduced species are assembling similarly on different continents. Overall, we found that substantial changes to populations are not necessarily a pre-condition for invasion success and that increases in species abundance are unusual. Instead, abundance at home predicts abundance away, a potentially useful additional criterion for biosecurity programmes. 相似文献
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Phosphorylation of a 15- to 17-kDa protein correlated with lytic function in cytotoxic T lymphocytes
M C Filiaggi D E McCulley J H Russell 《Journal of immunology (Baltimore, Md. : 1950)》1988,140(8):2702-2707
CTL are activated to lyse their targets through the interaction of the CTL-R and the appropriate Ag on the surface of the target cell. Experiments with tumor-promoting phorbol esters have suggested that the activation and translocation of protein kinase C (PKC) to the CTL membrane may be important in the activation process. We have studied the functional role of PKC in lytic signal transduction by correlating the phosphorylation of a set of CTL membrane proteins bound by the lectin Con A with lytic function in CTL clones. The data obtained indicate that the phosphorylation of a 15- to 17-kDa polypeptide in this subset is associated with the translocation of PKC to the membrane and the stimulation of lytic function. This suggests that the 15- to 17-kDa protein may be a physiologically relevant substrate for PKC translocated to the membrane as a result of Ag-specific perturbation of the CTL-R. 相似文献
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Spatial heterogeneity in species composition constrains plant community responses to herbivory and fertilisation
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Dorothee Hodapp Elizabeth T. Borer W. Stanley Harpole Eric M. Lind Eric W. Seabloom Peter B. Adler Juan Alberti Carlos A. Arnillas Jonathan D. Bakker Lori Biederman Marc Cadotte Elsa E. Cleland Scott Collins Philip A. Fay Jennifer Firn Nicole Hagenah Yann Hautier Oscar Iribarne Johannes M. H. Knops Rebecca L. McCulley Andrew MacDougall Joslin L. Moore John W. Morgan Brent Mortensen Kimberly J. La Pierre Anita C. Risch Martin Schütz Pablo Peri Carly J. Stevens Justin Wright Helmut Hillebrand 《Ecology letters》2018,21(9):1364-1371
Environmental change can result in substantial shifts in community composition. The associated immigration and extinction events are likely constrained by the spatial distribution of species. Still, studies on environmental change typically quantify biotic responses at single spatial (time series within a single plot) or temporal (spatial beta diversity at single time points) scales, ignoring their potential interdependence. Here, we use data from a global network of grassland experiments to determine how turnover responses to two major forms of environmental change – fertilisation and herbivore loss – are affected by species pool size and spatial compositional heterogeneity. Fertilisation led to higher rates of local extinction, whereas turnover in herbivore exclusion plots was driven by species replacement. Overall, sites with more spatially heterogeneous composition showed significantly higher rates of annual turnover, independent of species pool size and treatment. Taking into account spatial biodiversity aspects will therefore improve our understanding of consequences of global and anthropogenic change on community dynamics. 相似文献
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Role of suppressor T cells in herpes simplex virus-induced immune deviation. 总被引:2,自引:1,他引:1
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Herpes simplex virus type 1 inoculated into the anterior chamber of the mouse eye induces suppression of anti-herpes simplex virus T-cell-mediated delayed hypersensitivity. This suppression is virus-specific, and mediated by splenic T lymphocytes, and it can be adoptively transferred to naive recipients. 相似文献
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Conservation of nitrogen increases with precipitation across a major grassland gradient in the Central Great Plains of North America 总被引:1,自引:0,他引:1
Regional analyses and biogeochemical models predict that ecosystem N pools and N cycling rates must increase from the semi-arid
shortgrass steppe to the sub-humid tallgrass prairie of the Central Great Plains, yet few field data exist to evaluate these
predictions. In this paper, we measured rates of net N mineralization, N in above- and belowground primary production, total
soil organic matter N pools, soil inorganic N pools and capture in resin bags, decomposition rates, foliar 15N, and N use efficiency (NUE) across a precipitation gradient. We found that net N mineralization did not increase across
the gradient, despite more N generally being found in plant production, suggesting higher N uptake, in the wetter areas. NUE
of plants increased with precipitation, and δ15N foliar values and resin-captured N in soils decreased, all of which are consistent with the hypothesis that N cycling is
tighter at the wet end of the gradient. Litter decomposition appeared to play a role in maintaining this regional N cycling
trend: litter decomposed more slowly and released less N at the wet end of the gradient. These results suggest that immobilization
of N within the plant–soil system increases from semi-arid shortgrass steppe to sub-humid tallgrass prairie. Despite the fact
that N pools increase along a bio-climatic gradient from shortgrass steppe to mixed grass and tallgrass prairie, this element
becomes relatively more limiting and is therefore more tightly conserved at the wettest end of the gradient. Similar to findings
from forested systems, our results suggest that grassland N cycling becomes more open to N loss with increasing aridity. 相似文献
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Srinivas S. Somanchi Kelsey J. McCulley Anitha Somanchi Leo L. Chan Dean A. Lee 《PloS one》2015,10(10)
Natural killer (NK) cells belong to the innate arm of the immune system and though activated NK cells can modulate immune responses through the secretion of cytokines, their primary effector function is through target cell lysis. Accordingly, cytotoxicity assays are central to studying NK cell function. The 51Chromium release assay, is the “gold standard” for cytotoxicity assay, however, due to concerns over toxicity associated with the use and disposal of radioactive compounds there is a significant interest in non-radioactive methods. We have previously used the calcein release assay as a non-radioactive alternative for studying NK cell cytotoxicity. In this study, we show that the calcein release assay varies in its dynamic range for different tumor targets, and that the entrapped calcein could remain unreleased within apoptotic bodies of lysed tumor targets or incompletely released resulting in underestimation of percent specific lysis. To overcome these limitations, we developed a novel cytotoxicity assay using the Cellometer Vision Image Cytometer and compared this method to standard calcein release assay for measuring NK cell cytotoxicity. Using tumor lines K562, 721.221, and Jurkat, we demonstrate here that image cytometry shows significantly higher percent specific lysis of the target cells compared to the standard calcein release assay within the same experimental setup. Image cytometry is able to accurately analyze live target cells by excluding dimmer cells and smaller apoptotic bodies from viable target cell counts. The image cytometry-based cytotoxicity assay is a simple, direct and sensitive method and is an appealing option for routine cytotoxicity assay. 相似文献