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861.
Dean C Adams 《BMC evolutionary biology》2010,10(1):72
Background
Parallel evolution can occur when common environmental factors exert similar selective forces on morphological variation in populations in different geographic localities. Competition can also generate morphological shifts, and if competing species co-occur in multiple geographic regions, then repeated instances of competitively-driven morphological divergence (character displacement) can occur. Despite the importance of character displacement for inferring the role of selection in morphological evolution however, replicated instances of sympatric morphological divergence are understudied. 相似文献862.
The development of policy approaches for reducing nitrogen pollution to coastal waters of the USA 总被引:1,自引:0,他引:1
Robert W. Howarth 《中国科学C辑(英文版)》2005,48(2):791-806
Two-thirds of the coastal rivers and bays in the United States are degraded from nutrient pollution, and nitrogen inputs these waters continue to increase. The nitrogen comes from a variety of sources, including runoff from agricultural fields, concentrated animal feeding operations, atmospheric deposition from fossil fuel combustion, and sewage and septic wastes. Technical solutions for nitrogen pollution exist at reasonable cost. That most of these solutions have not yet been implemented to any significant extent across the United States suggests that new policy approaches are necessary. The best solution may involve a combination of voluntary and mandatory approaches, applying different approaches to different sources of nitrogen pollution. A watershed-based approach that relies heavily on voluntary mechanisms (such as crop-yield insurance to reduce over-fertilization) is likely to be the most effective for some sources of nitrogen (such as runoff from agricultural fields), while a uniform national regulatory approach may be better for others (such as NOx emissions from fossil fuel combustion). Implementation of management strategies should be carefully coupled to monitoring programs to assess the effectiveness of these strategies. While both nitrogen and phosphorus are important to control, the focus should be on nitrogen management, in part because nitrogen is more generally the causal agent of coastal eutrophication. Also, while nitrogen-control practices tend to also reduce phosphorus pollution, phosphorus-control practices often have little effect on nitrogen. Although current scientific and technical knowledge is sufficient to begin to make substantial progress toward solving coastal nitrogen pollution, progress will be made more quickly and more cost effectively with increased investment in appropriate scientific research. 相似文献
863.
864.
Weiduan Xu Jianmin Chen Glenn Yamasaki John E. Murphy Baisong Mei 《Molecular biotechnology》2010,45(3):248-256
Many therapeutic proteins require appropriate glycosylation for their biological activities and plasma half life. Coagulation
factor VIII (FVIII) is a glycoprotein which has extensive post-translational modification by N-linked glycosylation. The terminal
sialic acid in the N-linked glycans of FVIII is required for maximal circulatory half life. The extent of FVIII sialylation
can be determined by high pH anion-exchange chromatography coupled with a pulse electrochemical detector (HPAEC-PED), but
this requires a large amount of purified protein. Using FVIII as a model, the objective of the present study was to develop
assays that enable detection and prediction of sialylation deficiency at an early stage in the process and thus prevent downstream
product quality excursions. Lectin ECA (Erythrina Cristagalli) binds to unsialylated Galβ1-4 GlcNAc and the ECA-binding level (i.e., terminal Gal(β1-4) exposure) is inversely proportional
to the level of sialylation. By using ECA, a cell-based assay was developed to measure the global sialylation profile in FVIII
producing cells. To examine the Galβ1-4 exposure on the FVIII molecule in bioreactor tissue culture fluid (TCF), an ELISA-based
ECA-FVIII binding assay was developed. The ECA-binding specificity in both assays was assessed by ECA-specific sugar inhibitors
and neuraminidase digestion. The ECA-binding specificity was also independently confirmed by a ST3GAL4 siRNA knockdown experiment.
To establish the correlation between Galβ1-4 exposure and the HPAEC-PED determined FVIII sialylation value, the FVIII containing
bioreactor TCF and the purified FVIII samples were tested with ECA ELISA binding assay. The results indicated an inverse correlation
between ECA binding and the corresponding HPAEC-PED sialylation value. The ECA-binding assays are cost effective and can be
rapidly performed, thereby making them effective for in-process monitoring of protein sialylation. 相似文献
865.
Maintaining up-to-date annotation on reference genomes is becoming more important, not less, as the ability to rapidly and
cheaply resequence genomes expands. 相似文献
866.
Malliya Gounder Palanichamy Cai-Ling Zhang Bikash Mitra Boris Malyarchuk Miroslava Derenko Tapas Kumar Chaudhuri Ya-Ping Zhang 《BMC evolutionary biology》2010,10(1):304
Background
Tracing the genetic origin of central European farmer N1a lineages can provide a unique opportunity to assess the patterns of the farming technology spread into central Europe in the human prehistory. Here, we have chosen twelve N1a samples from modern populations which are most similar with the farmer N1a types and performed the complete mitochondrial DNA genome sequencing analysis. To assess the genetic and phylogeographic relationship, we performed a detailed survey of modern published N1a types from Eurasian and African populations. 相似文献867.
Dane Bicanic Darko Dimitrovski Svjetlana Luterotti Ksenija Marković Charlotte van Twisk Josephus G. Buijnsters Otto Dóka 《Food biophysics》2010,5(1):24-33
The trans-lycopene content of fresh tomato homogenates was assessed by means of the laser photoacoustic spectroscopy, the laser optothermal
window, micro-Raman spectroscopy, and colorimetry; none of these methods require the extraction from the product matrix prior
to the analysis. The wet chemistry method (high-performance liquid chromatography) was used as the absolute quantitative method.
Analytical figures of merit for all methods were compared statistically; best linear correlation was achieved for the chromaticity
index a* and chroma C*. 相似文献
868.
Igor Lipušček Marko Bohanec Leon Oblak Lidija Zadnik Stirn 《The International Journal of Life Cycle Assessment》2010,15(4):359-367
Background, aim and scope
Although life cycle assessment is frequently used in scientific studies of product comparison, many practitioners are looking for improvements in the normalisation, grouping and weighting of life cycle inventory results. Local conditions, which are well known to local experts, are very important to these steps. The goal of this work was to develop a computer-based decision support system for classifying wood products according to their influence on the environment in their whole life cycle. The model specifically addresses local conditions in the Republic of Slovenia and was developed by Slovenian experts. 相似文献869.
870.
Inclusion of carbonation during the life cycle of built and recycled concrete: influence on their carbon footprint 总被引:1,自引:0,他引:1
Frank Collins 《The International Journal of Life Cycle Assessment》2010,15(6):549-556