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排序方式: 共有436条查询结果,搜索用时 15 毫秒
1.
Shruti Deshmukh Stephen Burbine Erin Keaney Shib Shankar Banerjee Artee Panwar Christopher Peters Mary Herndon Derrick Rockosi Joey Mead Carol Barry 《Polymer Engineering and Science》2020,60(11):2782-2792
Highly-filled polymer systems include color masterbatches, feedstocks for powder injection molding, and rigid sheets with high levels of flame retardants, but they have not been explored for flexible sheet. This work investigated the (a) selecting a polymer matrix with enough melt strength and flexibility to form a stable sheet with high filler loading, (b) the maximum achievable filler loading for the sheet, and (c) optimizing the process of extruding a highly-filled flexible polymer system. Extrusion grade low-density polyethylene (LDPE) provided sufficient flexibility and permitted a maximum filler loading of 36 vol% (~78 wt%). Good dispersion of the nanoparticle filler, however, required two passes through multiple screw extruders and a small reduction in the viscosity of the LDPE. Sheet with thickness of 415 μm, surface roughness of <1 μm, and sufficient flexibility was extruded continuously at a rate of 10 m/min., but it required a more traditional coat hanger manifold to prevent filler hang up in the sheet die. The filler particles were distributed uniformly through the core and skin of the sheet, giving the sheet good mechanical properties. 相似文献
2.
James F. Mead Mitsu Kayama Raymond Reiser 《Journal of the American Oil Chemists' Society》1960,37(9):438-440
Summary Following injection ofTilapia mossambica with acetate-1-C14, their fatty acids were isolated, fractionated, and degraded. The high content of linoleic and arachidonic acids was evidently
derived from the diet. Degradation of these acids revealed a distribution of carbon-14 similar to that found in similar studies
on mammals.
This paper is based on work performed under contract No. AT-04-1-gen-12 between the Atomic Energy Commission and the University
of California at Los Angeles.
Part of this work was carried out at the Hawaii Marine Laboratory, where it was supported by a grant from the Pauley Fund.
Partially supported by a training grant from the National Heart Institute. Bethesda, Md. 相似文献
3.
Werten Paul J.L.; Carver John A.; Jaenicke Rainer; de Jong Wilfried W. 《Protein engineering, design & selection : PEDS》1996,9(11):1021-1028
ß-Crystallins are structural lens proteins with aconserved two-domain structure and variable N- and C-terminalextensions. These extensions are assumed to be involved in quaternaryinteractions within the ß-crystallin oligomers orwith other lens proteins. Therefore, the production of ßA3-and ßAl-crystallin from the single ßA3/A1mRNA by dual translation initiation is of interest. These crystallinsare identical, except that ßAl has a much shorterN-terminal extension than ßA3. This rare mechanismhas been conserved for over 250 million years during the evolutionof the ßA3/A1 gene, suggesting that the generationof different N-terminal extensions confers a selective advantage.We therefore compared the stability and association behaviourof recombinant ßA3- and ßAl-crystallin.Both proteins are equally stable in urea- and pH-induced denaturationexperiments. Gel filtration and analytical ultracentrifugationestablished that ßA3 and ßA1 both form homodimers.In the water-soluble proteins of bovine lens, ßA3and ßA1 are present in the same molecular weight fractions,indicating that they oligomerize equally with other ß-crystallins.1H-NMR spectroscopy showed that residues Met1 to Asn22 of theN-terminal extension of ßA3 have great flexibilityand are solvent exposed, excluding them from protein interactionsin the homodimer. These results indicate that the differentN-terminal extensions of ßA3 and ßA1 donot affect their homo- or heteromeric interactions. 相似文献
4.
The question of how affect arises and what affect indicates is examined from a feedback-based viewpoint on self-regulation. Using the analogy of action control as the attempt to diminish distance to a goal, a second feedback system is postulated that senses and regulates the rate at which the action-guiding system is functioning. This second system is seen as responsible for affect. Implications of these assertions and issues that arise from them are addressed in the remainder of the article. Several issues relate to the emotion model itself; others concern the relation between negative emotion and disengagement from goals. Relations to 3 other emotion theories are also addressed. The authors conclude that this view on affect is a useful supplement to other theories and that the concept of emotion is easily assimilated to feedback models of self-regulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
I Shiraishi DG Simpson W Carver R Price T Hirozane L Terracio TK Borg 《Canadian Metallurgical Quarterly》1997,29(8):2041-2052
Vinculin is a cytoskeletal protein that is believed to be an essential component in the linkage of cytoskeletal actin filaments to the plasma membrane. To investigate the precise function of vinculin in the development of cardiac myofibrils, antisense oligodeoxynucleotides complementary to vinculin mRNA were used to perturb the expression of the protein during myofibril assembly and arrangement in mouse cardiac myocytes. Fetal (day 18-20 post-conception) mouse cardiac myocytes were isolated by collagenase digestion, separated by Percoll density gradient centrifugation, and plated on aligned collagen gels. By 72 h of culture, mouse myocytes displayed an elongated in vivo-like phenotype in parallel with the aligned fibrils of the collagen gels with polarized arrays of myofibrils. Two different antisense oligonucleotides (20-mer) altered the formation of the tissue-like phenotype of myocytes. These antisense oligonucleotides suppressed vinculin protein expression at 43.5+/-26.8% and 48.7+/-20.9% when compared to myocytes that were not treated. Examination of these myocytes by confocal scanning laser and transmission electron microscopy revealed a disruption of the aligned in vivo-like phenotype, assembly of thick and thin filaments, and formulation of Z-bands. Random sequence 20-mer oligonucleotides used as controls had little detectable effect on vinculin protein expression (94.2+/-14.8%), cell shape, normal alignment or assembly of myofibrils. These results indicate that vinculin is a critical cytoskeletal component, that functions in the determination of cell shape and the arrangement and organization of developing myofibrils. 相似文献
6.
For many profoundly hearing-impaired listeners (hearing loss > 90 dB HL) speechreading is the most important means of communication; amplified speech may provide, at best, additional information to speechreading. In order to improve audiovisual communication, three speech pattern elements comprising voice-fundamental frequency (f0), the first formant (F1), and the first and the second formant (F1F2) were presented as supplements to speechreading. A fourth condition consisted of a natural speech supplement, a fifth of speechreading only. Twenty subjects were tested; all audiovisual speech scores were significantly higher than the purely visual scores. Audiovisual scores for amplified, natural speech were significantly higher than those for f0 and F1F2 coded speech. Scores for natural speech and for F1 coded speech were not significantly different. The relations between the increase in audiovisual speech scores over the visual scores and measures of difference limen for frequency (DLf) and gap detection were not clear. The most prominent correlations with the speech scores were found for the DLf at 125 Hz and for gap detection. 相似文献
7.
8.
Bob Brader Rachel C LeeRudy Plarre Wendell BurkholderG.Barrie Kitto Chuan Kao Lynn PolstonEleanora Dorneanu Ioana SzaboBill Mead Bob RouseDon Sullins Royal Denning 《Journal of Stored Products Research》2002,38(1):75-86
In collaboration with the United States Department of Agriculture and a number of major milling companies, the “Insect-Detect” immunoassay for analyzing insect contamination in grains has been compared with three more traditional methods, X-ray analysis, cracking and flotation, and the insect fragment test (IFT). Testing was carried out in blind fashion using clean wheat samples that were spiked with differing numbers of grain kernels infested with late instar larvae of the granary weevil (Sitophilus granarius (L.)). Three different laboratories analyzed the samples for each of the four methods. The collaborative trials showed that the insect immunoassay clearly provided the most accurate measurement of actual insect infestation, followed by X-ray analysis. While both cracking and flotation and IFT procedures provided a general measure of contamination, they showed much greater variability. 相似文献
9.
Ferreira AJ Ferreira CS Knobl T Moreno AM Bacarro MR Chen M Robach M Mead GC 《Journal of food protection》2003,66(3):490-492
In this study, a new competitive-exclusion (CE) product, Mucosal Starter Culture (MSC), was compared with two other CE products (Aviguard and Avifree) commercially available in Brazil to evaluate their ability to protect newly hatched chicks against colonization by a strain of Salmonella Kedougou. This study was based on a previously published and recommended method for such products. Separate groups of the chicks were dosed orally with the respective treatment materials and challenged 24 h later, and their ceca were examined for Salmonella 5 days after challenge. Under the test conditions, only MSC and Aviguard gave statistically significant (P < 0.05) protection to the chicks, but the MSC treatment yielded the lowest mean level of cecal carriage and the smallest proportion of Salmonella-positive birds. 相似文献
10.
A 225 GHz polarimetric radar 总被引:2,自引:0,他引:2
An incoherent 225-GHz polarimetric radar capable of measuring the Mueller matrix of point and distributed targets is described. The transmitter employs an extended interaction oscillator that transmit 60-W pulses of 50- to 600-ns duration. Incoherent measurements of the Mueller matrix are achieved by transmitting four linearly independent polarizations and measuring the scattered wave using a dual-polarized receiver. A novel calibration technique that requires a single in-scene reflector is presented. Polarimetric measurements are presented of a dihedral corner reflector and foliage which are the first polarimetric measurements reported at this wavelength. The foliage measurements indicate a pronounced sensitivity of the polarimetric data to fine-scale surface structure 相似文献