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81.
Pramodkumar D. Jadhav Yang Zuo Youn Young Shim Jianheng Shen Martin J. T. Reaney Ning Zhang Yong Wang 《International Journal of Food Science & Technology》2018,53(8):1972-1982
Linusorbs (LOs; a.k.a. cyclolinopeptides) are naturally occurring orbitides derived from flaxseed. These compounds consist of 8–10 amino acid residues, which are linked via an N ‐ to C‐terminal peptide bond with molecular masses of approximately 1 kDa. The LO circular structure makes them candidates for metal binding studies. Flaxseed extracts are known to suppress Pb and Cd toxicity. Hence, four metal salts surveyed include Zn(CH3COO)2, ZnSO4, Pb(CH3COO)2 and Cd(NO3)2 with pure LOs 1–5 . Proton NMR spectra indicated interaction of LOs with metal salts in solution and were used to determine impacts of methionine oxidation on interactions with metal ions. The methyl group of methionine S,S ‐ dioxide of related LOs did not show the same shift in the presence of Zn(CH3COO)2 and Pb(CH3COO)2 observed in their methionine S ‐ oxide analogues. Metal complexes were observed forming at 10?2 m to 10?4 m but not at lower concentrations (10?5 m to 10?8 m ). Mass spectrometry data confirmed that metal binding strength varied by metal in the order Zn(CH3COO)2<Pb(CH3COO)2<ZnSO4<Cd(NO3)2. 相似文献
82.
Ganeriwal S. Tsigkogiannis I. Shim H. Tsiatsis V. Srivastava M.B. Ganesan D. 《Networking, IEEE/ACM Transactions on》2009,17(3):843-856
Radio duty cycling has received significant attention in sensor networking literature, particularly in the form of protocols for medium access control and topology management. While many protocols have claimed to achieve significant duty-cycling benefits in theory and simulation, these benefits have often not translated into practice. The dominant factor that prevents the optimal usage of the radio in real deployment settings is time uncertainty between sensor nodes which results in overhead in the form of long packet preambles, guard bands, and excessive control packets for synchronization. This paper proposes an uncertainty-driven approach to duty-cycling, where a model of long-term clock drift is used to minimize the duty-cycling overhead. First, we use long-term empirical measurements to evaluate and analyze in-depth the interplay between three key parameters that influence long-term synchronization: synchronization rate, history of past synchronization beacons, and the estimation scheme. Second, we use this measurement-based study to design a rate-adaptive, energy-efficient long-term time synchronization algorithm that can adapt to changing clock drift and environmental conditions, while achieving application-specific precision with very high probability. Finally, we integrate our uncertainty-driven time synchronization scheme with the BMAC medium access control protocol, and demonstrate one to two orders of magnitude reduction in transmission energy consumption with negligible impact on packet loss rate. 相似文献
83.
In this work, to study the characteristics of carbon fiber-reinforced composites with different fiber cross-section types, such as round, C, and hollow-shape, the thermal conductivity and mechanical properties were investigated and compared. The thermal conductivity was measured by means of steady-state method to the parallel and perpendicular direction of reinforcing fibers. The mechanical properties were evaluated by a variety of test methods i.e., flexural, interlaminar shear strength, and impact strength. As a result, it was found that the thermal conductivity was greatly depended on the cross-section type of the reinforcing fibers, as well as, the reinforcing orientation. Especially, the anisotropy factor (k
///k
) and the thermal diffusivity factor (///) of C and hollow-type carbon fiber-reinforced composites showed about two times higher values than those of round-type one. Also, the mechanical results showed that C and hollow-type carbon fibers-reinforced composites had higher values than those of round-type one in all mechanical tested. These results were probably due to the basic properties of non-circular (C and hollow-type) carbon fiber which can improve interfacial binding forces and widen interfacial contact area between reinforcement and matrix, resulting in effectively transferring the applied stress. 相似文献
84.
Mixed Dimensional Coupling in Finite Element Stress Analysis 总被引:4,自引:0,他引:4
Many analysis models utilize finite elements of reduced dimension. However, to capture stress concentrations at local details,
it would be desirable to combine the reduced dimensional element types with higher dimensional elements in a single finite
element model. It is therefore important in such cases to integrate into the analyses some scheme for coupling the element
types that conforms to the governing equations of the problem. In this paper, a novel method that can correctly couple beams
to solids, beams to shells and shells to solids for elastic problems is presented. The approach adopted is to equate the work
done on either side of the interface between dimensions, and this leads to multi-point constraint equations, thus providing
a relationship among nodal degrees of freedom between the differing element types. Example results show that the proposed
technique does not introduce any spurious stresses at the dimensional interfaces.
ID="A1" Correspondence and offprint requests to: C. G. Armstrong, School of Mechanical and Manufacturing Engineering, The Queen's University of Belfast, Ashby Building,
Stranmillis Road, Belfast BT9 5AH, Northern Ireland. E-mail: c.armstrong@qub.ac.uk 相似文献
85.
Short communication: lack of stage-specific embryonic antigen-1 expression by bovine embryos and primordial germ cells 总被引:1,自引:0,他引:1
The objective of this study was to determine whether stage-specific embryonic antigen-1, a cellular marker commonly used to identify murine undifferentiated embryonic cells, is also a useful marker for bovine pluripotent cells. Expression of stage-specific embryonic antigen-1 was examined by indirect immunohistochemistry on bovine preimplantation embryos and on primordial germ cells contained in the genital ridge. Expression of stage-specific embryonic antigen-1 was not observed in any of the cleavage-stage bovine embryos examined, including one-cell, two-cell, four-cell, eight-cell, morula, and blastocyst stages, nor in tissue sections of bovine genital ridges collected from embryos on d 34, 37, and 40 of gestation. As expected, expression of stage-specific embryonic antigen-1 was detected on murine preimplantation embryos and on murine teratocarcinoma cells. Results of this study indicate that, unlike in the mouse, stage-specific embryonic antigen-1 is not a useful cellular marker for pluripotent bovine embryonic cells or bovine primordial germ cells. 相似文献
86.
Sang Chul Shim Fumitaka Tsukihashi Nobuo Sano 《Metallurgical and Materials Transactions B》1993,24(2):333-337
Although a great number of works on BaO-bearing fluxes for refining Fe-Cr and Fe-Mn alloys have been carried out, there still
remain several unresolved problems on using them in the refining process. The principal aim of the present study is to understand
the thermodynamic properties of the BaO-MnO system, which has been shown to be very effective for dephosphorization of Fe-Mn
alloys. The activity of manganese oxide in the BaO-MnO flux was measured at 1573 and 1673 K by equilibrating the flux, a Ag-Mn
alloy, and a gas mixture of CO and CO2 as functions of the flux composition and temperature. The influence of BaF2, which is an effective additive for lowering the melting temperature of the flux, on the thermodynamics of the BaO-MnO system,
including the solubility of MnO in the BaO-BaF2 system, was also investigated. 相似文献
87.
The present study was carried out to examine the changes in functional properties of cholesterol-removed whipping cream by beta-cyclodextrin (beta-CD) treatment. The cholesterol removal rate reached over 90% in cream before whipping in all conditions (different stirring time and speed) applied. The apparent viscosity of beta-CD treated cream after whipping increased with increased stirring time and speed. Comparatively, the overrun percentage reached to 150%, and foam instability was measured as 2.5 ml deformed cream with lower stirring time (10 min) and speed (400 rpm). The thiobarbituric acid value of cholesterol-removed whipping cream increased from 0.08 to 0.14 stored at 4 degrees C during 4 wk; however, no difference was found compared with that of control. Above results indicated that beta-CD treatment process for cholesterol removal did not show a profound adverse effect on functional properties of cream after whipping. 相似文献
88.
89.
Poly(L-lactide)-block-poly(ethylene oxide)-block-poly(L-lactide) triblock copolymers (PLLA-b-PEO-b-PLLA) were fractionated in terms of the number of LLA units by liquid chromatography at the critical condition (LCCC) of PEO block. The fractionated samples were identified using MALDI-TOF mass spectrometry. The dependence of the LCCC retention of the diblock and triblock copolymers on the degree of polymerization of PLLA block(s) follows Martin's rule very well. Unlike the case of PEO-b-PLLA diblock copolymer reported earlier (Lee, H.; et al. Macromolecules 1999, 32, 4143), however, a splitting of the elution peaks containing the same number of LLA units was found. The peak splitting was ascribed to the different length distributions of PLLA blocks at the two ends of the PEO block. From the relative intensities of the peaks, the split peaks were assigned to different isomeric structures of the PLLA blocks. From these results we conclude that the interaction of the triblock copolymers with the stationary phase is affected by the distribution of the interacting blocks at the two ends of the center PEO block, in addition to the total number of LLA units in the triblock copolymer. 相似文献
90.
The cure rate of diglycidyl ether of bisphenol A (DGEBA)/4,4-methylene dianiline (MDA) system with or without MDA-endcapped carboxyl-terminated butadiene acrylonitrile (CTBN) rubber was studied by autocatalytic cure rate expression. All the cumulative conversion curves for DGEBA/MDA system with or without MDA-endcapped CTBN (20 phr) showed s-shape and this meant that the two systems followed the typical autocatalytic reaction. The cure rate of the system with MDA-endcapped CTBN (20 phr) was faster than that of the system without MDA-endcapped CTBN (20 phr). The activation energies of k
1 and k
2 for DGEBA/MDA system were 54.01 kJ/mol and 44.06 kJ/mol, respectively and those of k
1 and k
2 for the system with MDA-endcapped CTBN (20 phr) were 47.71 kJ/mol and 40.95 kJ/mol. 相似文献