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Structural Studies of Jennite and 1.4 nm Tobermorite: Disordered Layering along the [100] of Jennite
Dwight Viehland Lijian J. Yuan Z. Xu Xian-Dong Cong R. James Kirkpatrick 《Journal of the American Ceramic Society》1997,80(12):3021-3028
Transmission electron microscopy of synthetic jennite reveals strong streaking in the electron diffraction patterns along the [100], along which dark-field imaging and lattice fringing confirm the presence of a layering with a striation-like morphology. The average periodicity between the layers is ∼35 Å; however, there is significant variation around this value in the range of 20-40 Å, which is in agreement with the range of periodicities that are associated with the streaking in the diffraction patterns. These results clearly demonstrate the presence of a layering along the [100] with a periodicity that varies spatially throughout the specimen, which results in the presence of a disordered modulated structure. We believe that the disorder is induced by frozen-in fluctuations in the local calcium:silicon ratio, which correspondingly results in fluctuations in the local structural order and periodicity of the modulated structure. Similar studies of 1.4-nm tobermorite have revealed streaking along the [100]; however, it was weak and diffuse. 相似文献
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Although object-based attention enhances perceptual processing of information appearing within the boundaries of a selected object, little is known about the consequences for information in the object's surround. The authors show that distance from an attended object's center of mass determines reaction time (RT) to targets in the surround. Of 2 targets in the surround, both equidistant from a cue, the target closer to the center of mass was detected faster. Moreover, RT was shown to be a linear function of distance from the center of mass of a fixed, attended object, and changes to the shape of the object and its center of mass predictably altered RT. Object-based attention leads to a pattern of facilitation in the surround that may contribute to the organization of visual scenes. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Mehrmohammadi M Qu M Ma LL Romanovicz DK Johnston KP Sokolov KV Emelianov SY 《Nanotechnology》2011,22(41):415105
As applications of nanoparticles in medical imaging and biomedicine rapidly expand, the interactions of nanoparticles with living cells have become an area of active interest. For example, intracellular accumulation of nanoparticles-an important part of cell-nanoparticle interaction-has been well studied using plasmonic nanoparticles and optical or optics-based techniques due to the change in optical properties of the nanoparticle aggregates. However, magnetic nanoparticles, despite their wide range of clinical applications, do not exhibit plasmonic-resonant properties and therefore their intracellular aggregation cannot be detected by optics-based imaging techniques. In this study, we investigated the feasibility of a novel imaging technique-pulsed magneto-motive ultrasound (pMMUS)-to identify intracellular accumulation of endocytosed magnetic nanoparticles. In pMMUS imaging a focused, high intensity, pulsed magnetic field is used to excite the cells labeled with magnetic nanoparticles, and ultrasound imaging is then used to monitor the mechanical response of the tissue. We demonstrated previously that clusters of magnetic nanoparticles amplify the pMMUS signal in comparison to the signal from individual nanoparticles. Here we further demonstrate that pMMUS imaging can identify interaction between magnetic nanoparticles and living cells, i.e.?intracellular accumulation of nanoparticles within the cells. The results of our study suggest that pMMUS imaging can not only detect the presence of magnetic nanoparticles but also provides information about their intracellular accumulation non-invasively and in real-time. 相似文献
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Previs MJ VanBuren P Begin KJ Vigoreaux JO LeWinter MM Matthews DE 《Analytical chemistry》2008,80(15):5864-5872
The identification and quantification of specific phosphorylation sites within a protein by mass spectrometry has proved challenging when measured from peptides after protein digestion because each peptide has a unique ionization efficiency that alters with modification, such as phosphorylation, and because phosphorylation can alter cleavage by trypsin, shifting peptide distribution. In addition, some phosphorylated peptides generated by tryptic digest are small and hydrophilic and, thus, are not retained well on commonly used C18 columns. We have developed a novel C-terminal peptide (2)H-labeling derivatization strategy and a mass balance approach to quantify phosphorylation. We illustrate the application of our method using electrospray ionization liquid chromatography-mass spectrometry by quantifying phosphorylation of troponin I with protein kinase A and protein kinase C. The method also improves the retention and elution of hydrophilic peptides. The method defines phosphorylation without having to measure the phosphorylated peptides directly or being affected by variable miscleavage. Measurement of phosphorylation is shown to be linear (relative standard error <5%) with a detection limit of <10%. 相似文献
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A process has been developed for extracting the corn oil from distillers’ grains rather than the incoming corn. Yields by
various methods of recovery are considered. Solvent extraction by the use of low boiling petroleum naphthas was adopted. Pilot
unit extraction and refining was followed by oil acceptance by refiners. Feeding tests showed the extracted grains to be superior
to the original distillers’ grains.
The 100-ton extraction plant expects to be in full operation the early part of 1938. 相似文献