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101.
Swanson HK Johnston TA Schindler DW Bodaly RA Whittle DM 《Environmental science & technology》2006,40(5):1439-1446
We compared total mercury concentrations ([Hg]) among 6 forage fish species in 25 central Canadian lakes and related [Hg] to adjusted-delta15N (an index of trophic position), delta13C, growth rate, and a suite of environmental variables. Growth rates were also compared among species and related to environmental variables. We found that rainbow smelt (Osmerus mordax), a recent invader in many of these lakes, had intermediate [Hg] and growth rates relative to other species. Forage fish growth rates differed significantly among species and were related to latitude (inverse relationship) and lake conductivity (positive relationship). Mercury concentrations also differed significantly among species and the strongest predictors were growth rate and lake conductivity; [Hg] was significantly and negatively related to both. Adjusted-delta15N explained very little variation in [Hg] and was significant only when the analysis was restricted to biotic variables. These results indicate that biomagnification may not be observed at fine scales of trophic differentiation and that rainbow smelt are unlikely to cause post-invasion [Hg] increases in most predatory fish species. 相似文献
102.
Cytotoxicity of human RNase-based immunotoxins requires cytosolic access and resistance to ribonuclease inhibition 总被引:1,自引:0,他引:1
Immunotoxins are targeted therapeutics designed to kill cancer cells. The targeting moiety of an immunotoxin selectively binds to a tumor cell and targets it for death via an attached toxin. Because the toxins are typically of plant or bacterial origin, their clinical use is limited by immunogenicity and nonspecific toxicity. To circumvent these problems, we have begun to engineer immunotoxins containing human pancreatic ribonuclease. Here we describe the generation of ribonuclease mutants designed to evade a ubiquitous cytosolic inhibitor that would otherwise block cytotoxicity. Two mutants retained catalytic activity and were relatively resistant to the inhibitor. To deliver them to human T leukemic cells, these ribonuclease variants were fused to a single chain Fv fragment specific for CD 7.The ribonuclease-sFv fusion proteins bound CD 7(+) T cells and were internalized yet were not cytotoxic. Transfection of the proteins directly into the cytosol reduced cell viability, suggesting that the failure of the immunotoxins to kill cells when added externally resulted from the inability of the ribonuclease moiety to access the cytosol efficiently. Our results indicate appropriate intracellular routing, as well as resistance to inhibition, is critical to the cytotoxicity of human ribonuclease-based immunotoxins. 相似文献
103.
This paper presents the design of a multichannel imaging system where the different optical channels have a different angular resolution and field-of-view. Such an imaging system is able to resolve fine details in a small region of interest through the channel that has the highest angular resolution (0.0096°) while controlling the surrounding region through the channel that has the widest field-of-view (2×40°). An interesting feature of such a multichannel, multiresolution imaging system is that various image processing algorithms can be applied at different segments of the image sensor. We have designed a three channel imaging system where each optical channel consists of four aspheric lens surfaces. These three imaging channels share a single image sensor with a resolution of 1440×960 and a 10 μm pixel size. All imaging channels have diffraction-limited performance ensuring good overall image quality. 相似文献
104.
Jeffrey T. Rominger Anne F. Lightbody Heidi M. Nepf 《Canadian Metallurgical Quarterly》2010,136(12):994-1002
Vegetation was added to a fully developed sandy point bar in the meander of a constructed stream. Significant changes in the flow structure and bed topography were observed. As expected, the addition of vegetative resistance decreased the depth-averaged streamwise velocity over the bar and increased it in the open region. In addition, the secondary circulation increased in strength but became confined to the deepest section of the channel. Over the point bar, the secondary flow was entirely outward, i.e., toward the outer bank. The changes in flow led to changes in bar shape. Although the region of the bar closest to the inner bank accumulated sediment, erosion of the bar and the removal of plants by scouring were observed at the interface between the planted bar and the open channel. 相似文献
105.
Mirjam Frischknecht Theodorus H.E. Meuwissen Beat Bapst Franz R. Seefried Christine Flury Dorian Garrick Heidi Signer-Hasler Christian Stricker Anna Bieber Ruedi Fries Ingolf Russ Johann Sölkner Alessandro Bagnato Birgit Gredler-Grandl 《Journal of dairy science》2018,101(2):1292-1296
The accuracy of genomic prediction determines response to selection. It has been hypothesized that accuracy of genomic breeding values can be increased by a higher density of variants. We used imputed whole-genome sequence data and various single nucleotide polymorphism (SNP) selection criteria to estimate genomic breeding values in Brown Swiss cattle. The extreme scenarios were 50K SNP chip data and whole-genome sequence data with intermediate scenarios using linkage disequilibrium-pruned whole-genome sequence variants, only variants predicted to be missense, or the top 50K variants from genome-wide association studies. We estimated genomic breeding values for 3 traits (somatic cell score, nonreturn rate in heifers, and stature) and found differences in accuracy levels between traits. However, among different SNP sets, accuracy was very similar. In our analyses, sequence data led to a marginal increase in accuracy for 1 trait and was lower than 50K for the other traits. We concluded that the inclusion of imputed whole-genome sequence data does not lead to increased accuracy of genomic prediction with the methods. 相似文献
106.
Heidi Hiitiö Satu Pyörälä Suvi Taponen Päivi Rajala-Schultz Heli Simojoki 《Journal of dairy science》2018,101(6):5267-5276
Diagnosis of bovine intramammary infection (IMI) has traditionally been based on bacterial culture, but currently IMI can also be detected with DNA based methods, such as multiplex real-time PCR. The aim of this study was to describe the elimination of bacteria in experimentally induced IMI on the quarter level, using conventional bacterial culture (BC) and multiplex real-time PCR. Two coagulase-negative staphylococcal species, Staphylococcus epidermidis and Staphylococcus simulans, were experimentally inoculated into 14 healthy quarters of 8 dairy cows during 4 consecutive study periods. Intramammary infections were followed with 20 milk samplings per each quarter. Milk somatic cell count was monitored to evaluate the inflammation process in the quarters. Four quarters cured spontaneously during the study period according to the culture. The PCR detected staphylococcal DNA from these quarters for several days after they were defined as cured in BC. Agreement between BC and PCR results varied from substantial to almost perfect agreement for the first 36 h postchallenge, decreasing to moderate levels toward the end of the sampling period. Based on this study, we recommend collecting possible follow-up samples to assess the bacteriological cure from IMI not until 2 to 3 wk after the onset of mastitis or after the quarter milk somatic cell count has normalized when PCR is used. 相似文献
107.
Ashiq Mohammad Dhekne Pushkar Hamada Atef Saad Sahu Puspendu Mahato B. Minz R. K. Ghosh Chowdhury Sandip Pentti Karjalainen L. 《Metallurgical and Materials Transactions A》2017,48(10):4842-4856
Metallurgical and Materials Transactions A - The evolution of microstructure and texture of a two-phase austenite-ferrite twinning-induced plasticity steel during cold rolling was investigated and... 相似文献
108.
AbstractKenya is among the first countries in sub-Saharan Africa to formally require the assessment of public policies, plans and programs. National strategic environmental assessment (SEA) guidelines were finalized in 2012 to adapt and enhance SEA practice in the Kenyan context. The purpose of this research was to examine recent Kenyan SEA, with a particular emphasis on public participation, by developing and applying an analysis framework that both incorporates commonly accepted SEA principles and approaches and is cognizant of the national context in shaping SEA practice. Results reveal that a number of SEA practices are consistent with the framework in the nine cases considered, such as containing standard SEA components and developing monitoring plans. A requirement that each SEA must include educating the public about SEA is an innovative local adaptation. Results also show a number of practices that are still emerging, such as initiating SEA early and disseminating results to the participants. We conclude that SEA is still developing in Kenya, but processes for conducting it are slowly adapting to the Kenyan context. 相似文献
109.
Fatty Acid Profile of Sunshine Bass: I. Profile Change is Affected by Initial Composition and Differs Among Tissues 总被引:1,自引:0,他引:1
Fatty acid (FA) composition of fillet tissue can be tailored by transitioning fish from alternative lipid-based, low long-chain polyunsaturated fatty acid (LC-PUFA) grow-out feeds to high LC-PUFA "finishing" feeds. To address whether grow-out feed composition influences the responsiveness of fillet tissue to finishing, sunshine bass (SB, Morone chrysops x M. saxatilis) were reared to a submarketable size on grow-out feeds containing fish oil (FO) or a 50:50 blend of FO and coconut (CO), grapeseed (GO), linseed (LO), or poultry (PO) oil. For the final 8 weeks of the trial, fish were either maintained on assigned grow-out feeds or finished with the 100% FO feed. Production performance was unaffected by dietary lipid source, but fillet FA profile generally conformed to nutritional history. Regardless of grow-out regimen, finishing had a significant restorative effect on fillet FA composition; however, complete restoration of control levels of 20:5n-3, 22:6n-3, total LC-PUFA and n-3:n-6 FA ratio was achieved only among fish fed the CO-based grow-out feed. Saturated fatty acids (SFA) appear to be preferential catabolic substrates, whereas medium-chain and long-chain PUFA are selectively deposited in tissues. Provision of SFA in grow-out feeds appears to optimize selective FA metabolism and restoration of beneficial fillet FA profile during finishing. 相似文献
110.
De Brabandere H Forsgard N Israelsson L Petterson J Rydin E Waldebäck M Sjöberg PJ 《Analytical chemistry》2008,80(17):6689-6697
The structures of organic phosphorous (P) compounds in aquatic sediments are to a large extent unknown although these compounds are considered to play an important role in regulating lake trophic status. To enhance identification of these compounds, a liquid chromatography (LC) method for their separation was developed. The stationary phase was porous graphitic carbon (PGC), and the mobile phases used in the gradient elution were compatible with both inductive coupled plasma atomic emission spectroscopy (ICP-AES) and electrospray ionization tandem mass spectrometry (ESI-MS/MS). With LC-ICP-AES, eight different P containing peaks could be observed in the P chromatogram indicating that at least eight different P compounds were separated. With the setup of an information dependent acquisition (IDA) with ESI-MS/MS, the mass over charge ( m/ z) of compounds containing a phosphate group (H 2PO 3 (-), m/ z 97) could be measured and further fragmentation experiments gave additional information on the structure of almost 40 separated P compounds, several were verified to be nucleotides. ICP-AES was very suitable in the development of the LC method and allowed screening and quantification of P compounds. The presented LC-ESI-MS/MS technique was able to identify several sediment organic P compounds. 相似文献