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171.
Wing dikes and other anthropogenic modifications have heavily altered riverine ecosystems. Recent efforts to reach a compromise between the needs of the river transportation industry and natural resource conservation include dike modification. Dike notching permits water flow through the landward portion of the dike and has been purported to provide suitable habitat for fish and other river biota while maintaining the navigation channel. L‐head dikes are flow‐control structures that create calm backwater‐like habitats downstream. However, few researchers have examined the actual effects of dike notching on water quality or fish communities. We compared standardized catch per unit effort and overall community structure for 50 fish species among un‐notched dikes, notched dikes and L‐head dikes in the Middle Mississippi River, sampled as part of the US Geological Survey's Long‐Term Resource Monitoring Program. There were no differences in standardized catch per unit effort for 64% of the fishes examined. Five species known to be associated with lotic habitats were most abundant near L‐head dikes. Seven species were more abundant at un‐notched dikes than notched dikes, while six species were more abundant at notched dikes than un‐notched dikes. Non‐metric multidimensional scaling suggested differences in overall fish community structure between un‐notched and other dike types. Detailed physical habitat studies should be conducted to better understand the effects of dike modification. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
172.
In this paper, an open-tubular capillary cell affinity chromatography (OT-CAC) method to enrich and separate target cells is described. Open tubular capillaries coated with anti-CD4, anti-CD14, or anti-CD19 antibodies were used as affinity chromatography columns to separate target blood cells. Cells were eluted using either shear force or bubbles. Bubbles were used to elute the captured cells without diluting the captured cells appreciably, while maintaining viability (the viability of the recovered cells was 85.83 +/- 7.34%; the viability of the cells was 90.41 +/- 3.49% before separation). Several aspects of the OT-CAC method were studied, such as the affinity of one antibody between two different cell lines, the effect of shear force, and the recovery of captured cells. Single- and multicell type separations were demonstrated by isolating CD4+ cells with antiCD4 coated capillary and isolating CD4+ and CD19+ cells with two capillaries in tandem from blood samples. In the one cell type isolation test, an average of 87.7% of the recovered cells from antiCD4 capillary were lymphocytes and an average of 97.7% of those lymphocytes were CD4+ cells. In the original blood sample, only 14.2% of the leukocytes were CD4+ cells. Two capillary columns were also run in tandem, separating two blood cell types from a single sample with high purity. The use of different elution shear forces was demonstrated to selectively elute one cell type. This method is an inexpensive, rapid, and effective method to separate target cells from blood samples.  相似文献   
173.
Anion analysis is of great importance to many scientific areas of interest. Problems with negative mode ESI-MS prevent researchers from achieving sensitive detection for anions. Recently, we have shown that cationic reagents can be paired with anions, such that detection can be done in the positive mode, allowing for low limits of detections for anions using ESI-MS. In this analysis, we present the use of 16 newly synthesized flexible linear tricationic ion-paring reagents for the detection of 11 divalent anions. These reagents greatly differ in structure from previously reported trigonal tricationic ion-pairing agents, such that they are far more flexible. Here we present the structural features of these linear trications that make for good ion-pairing agents as well as show the advantage of using these more flexible ion-pairing reagents. In fact, the limit of detection for sulfate using the best linear trication was found to be 25 times lower than when the best rigid trication was used. Also, MS/MS experiments were performed on the trication-dianion complex to significantly reduce the detection limit for many dianions. Limits of detection in this analysis were as low as 50 fg.  相似文献   
174.
Cell化生产一方面可通过强制平衡提升线平衡率、消除无价值劳动时间等方法从而提升工人的效率,另一方面又可通过提升产线的空间利用率,减少在制品来节约生产与储存空间.经实例验证,导入Cell化生产,能将人的生产率提高30%,生产空间节约50%以上.  相似文献   
175.
Lipopolysaccharide (LPS) is a major component of the outer membrane of Gram-negative bacteria. The lipid A region of LPS stimulates the immune system in a structure-dependent manner. We have previously identified the two major lipid A species from Francisella tularensis as asymmetric tetraacylated structures containing four long acyl chains (16 and 18 carbons) and a single phosphate group that is partially modified by galactosamine (Phillips, N. J.; Schilling B.; McLendon, M. K.; Apicella, M. A.; Gibson, B. W. Infect. Immun. 2004, 72, 5340-5348). In the current study, we used matrix-assisted laser desorption/ionization on an intermediate vacuum source (vMALDI) coupled to a linear ion trap (LIT) mass spectrometer in multiple-stage mass fragmentation mode (MSn) to determine the structures of several minor and low abundant lipid A species present in F. tularensis, Francisella novicida, and Francisella philomiragia LPS that have not been previously characterized. Comprehensive vMALDI-MSn fragmentation studies allowed us to deduce the composition and the position of the fatty acid substituents within the lipid A moieties. Unexpectedly, most of these minor lipid A species consisted of multiple isobaric species with acyl chains of various lengths. Moreover, we found that a small portion of these lipid A species may be modified by the addition of a hexose or hexosamine sugar, in addition to the galactosamine that was previously identified. Overall, we found that MSn analysis on the vMALDI-LIT-MS platform was highly efficient and sensitive, allowing for thorough analysis of very minor lipid A species.  相似文献   
176.
Internalization and subcellular localization in HeLa cells of gold nanoparticles modified with the SV40 large T antigen were quantified using inductively coupled plasma optical emission spectroscopy (ICP-OES). Internalization was monitored as a function of incubation time, temperature, nanoparticle diameter, and large T surface coverage. Increasing the amount of large T peptides per gold nanoparticle complex, by either increasing the coverage at constant nanoparticle diameter or by increasing the nanoparticle diameter at constant large T coverage, resulted in more cellular internalization. In addition, nuclear fractionation was performed to quantify nuclear localization of these complexes as a function of large T coverage. In contrast to our prior qualitative investigations of nuclear localization by video-enhanced color differential interference contrast microscopy (VEC-DIC), ICP-OES was able to detect nanoparticles inside fractionated cell nuclei. Although increasing the large T coverage was found to afford higher cell internalization and nuclear targeting, quantitative evaluation of cytotoxicity revealed that higher large T coverages also resulted in greater cytotoxicity. The ICP-OES and nuclear fractionation techniques reported here are valuable tools that can add important quantitative information to optical and electron imaging methods such as VEC-DIC and transmission electron microscopy regarding the fate of nanoparticles in cells.  相似文献   
177.
In the present study, linkages were examined between parental behaviors (maternal practices) at bedtime, emotional availability of mothering at bedtime, and infant sleep quality in a cross-sectional sample of families with infants between 1 and 24 months of age. Observations of maternal behaviors and maternal emotional availability were conducted independently by 2 sets of trained observers who were blind to data being coded by the other. With infant age statistically controlled, specific maternal behaviors at bedtime were unrelated to infant sleep disruptions at bedtime and during the night. By contrast, emotional availability of mothering at bedtime was significantly and inversely related to infant sleep disruption, and, although these links were stronger for younger infants, they were significant for older infants as well. Maternal emotional availability was also inversely linked with mothers' ratings of whether their infants had sleep difficulties. These findings demonstrate that parents' emotional availability at bedtimes may be as important, if not more important, than bedtime practices in predicting infant sleep quality. Results support the theoretical premise that parents' emotional availability to children in sleep contexts promotes feelings of safety and security and, as a result, better-regulated child sleep. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
178.
179.
Many 3D in vitro models induce breast cancer spheroid formation; however, this alone does not recapitulate the complex in vivo phenotype. To effectively screen therapeutics, it is urgently needed to validate in vitro cancer spheroid models against the gold standard of xenografts. A new oxime‐crosslinked hyaluronan (HA) hydrogel is designed, manipulating gelation rate and mechanical properties to grow breast cancer spheroids in 3D. This HA‐oxime breast cancer model maintains the gene expression profile most similar to that of tumor xenografts based on a pan‐cancer gene expression profile (comprising 730 genes) of three different human breast cancer subtypes compared to Matrigel or conventional 2D culture. Differences in gene expression between breast cancer cultures in HA‐oxime versus Matrigel or 2D are confirmed for 12 canonical pathways by gene set variation analysis. Importantly, drug response is dependent on the culture method. Breast cancer cells respond better to the Rac inhibitor (EHT‐1864) and the PI3K inhibitor (AZD6482) when cultured in HA‐oxime versus Matrigel. This study demonstrates the superiority of an HA‐based hydrogel as a platform for in vitro breast cancer culture of both primary, patient‐derived cells and cell lines, and provides a hydrogel culture model that closely matches that in vivo.  相似文献   
180.
Vineyard applications of foliar nitrogen (N) and sulfur were evaluated in the Yadkin Valley of North Carolina in 2011 and 2012 as a means to modify grape composition of Vitis vinifera cv. petit manseng. Four treatments were applied each year in a randomized complete block design with six replicates of six vines each: untreated control, soil N at 30?kg/ha, foliar N at 15?kg/ha and foliar N at 15?kg/ha plus sulfur at 5?kg/ha. Fruit ammonia and yeast assimilable nitrogen (YAN) concentrations increased in foliar-treated vines both seasons compared to control vines. Total glycosides (TGGs) increased ~80% in foliar N/sulfur-treated vines compared to control vines in 2011, and TGGs increased ~157% in foliar N/sulfur-treated vines relative to glycoside level in foliar N alone in 2012. Foliar N and foliar N/sulfur applications increased the majority of amino acid concentrations analyzed in 2011. Measured concentrations of various amino acids, partly responsible for aroma and flavor of petit manseng wines, were differentially dependent on the method of N application. Foliar applied nitrogen may be an effective technique to contribute to berry composition optimization of petit manseng grown in a warm, humid climate.  相似文献   
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