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  • 1
    Language: English
    In: Science (New York, N.Y.), 20 September 2013, Vol.341(6152), pp.1384-7
    Description: Virtually since the discovery of nitrogen-fixing Rhizobium-legume symbioses, researchers have dreamed of transferring this capability into nonlegume crop species (for example, corn). In general, nonlegumes were assumed to lack the ability to respond to the rhizobial lipo-chitin Nod factors, which are the essential signal molecules that trigger legume nodulation. However, our data indicate that Arabidopsis thaliana plants, as well as other nonlegumes, recognize the rhizobial Nod factor via a mechanism that results in strong suppression of microbe-associated molecular pattern (MAMP)-triggered immunity. The mechanism of action leads to reduced levels of pattern-recognition receptors on the plasma membrane involved in MAMP recognition.
    Keywords: Arabidopsis -- Immunology ; Immunity, Innate -- Immunology ; Lipopolysaccharides -- Immunology
    ISSN: 00368075
    E-ISSN: 1095-9203
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  • 2
    Language: English
    In: Geochimica et Cosmochimica Acta, Sept 15, 2015, Vol.165, p.35(9)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.gca.2015.05.028 Byline: Yan Liang Abstract: Closure temperature is defined as the lower temperature limit at which the element of interest effectively ceases diffusive exchange with its surrounding medium during cooling. Here we generalize the classic equation of Dodson (1973) for cooling mono-mineralic systems to cooling bi-mineralic aggregates by considering diffusive exchange of a trace element between the two minerals in a closed system. We present a simple analytical model that includes key parameters affecting the closure temperature of a trace element in cooling bi-mineralic systems: cooling rate, temperature-dependent diffusion coefficients for the trace element in the two minerals, temperature-dependent partition coefficient of the trace element between the two minerals, effective grain sizes of the two minerals, and volume proportions of the minerals in the system. We show that closure temperatures of a trace element in cooling bi-mineralic systems are bounded by the closure temperatures of the trace element in the two mono-mineralic systems and that our generalized model reduces to Dodson's equation when one of the mineral serves as "an effective infinite" reservoir to the other mineral. Application to closure temperatures of REE in orthopyroxene and clinopyroxene bi-mineralic systems highlights the importance of REE diffusion and partitioning in the pyroxenes as well as clinopyroxene modal abundance and grain size in the systems. Closure temperatures for REE in two-pyroxene bearing equigranular rocks are controlled primarily by diffusion in orthopyroxene unless the modal abundance of clinopyroxene is very small. This has important bearings on the interpretation of temperatures derived from the REE-in-two-pyroxene thermometer. Article History: Received 13 September 2014; Accepted 13 May 2015 Article Note: (miscellaneous) Associate editor: EIC Marc Norman
    ISSN: 0016-7037
    Source: Cengage Learning, Inc.
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  • 3
    Language: English
    In: Geochimica et Cosmochimica Acta, Feb 1, 2013, Vol.102, p.246(15)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.gca.2012.10.035 Byline: Yan Liang, Chenguang Sun, Lijing Yao Abstract: A REE-in-two-pyroxene thermometer for mafic and ultramafic rocks has been developed on the basis of the temperature and pyroxene composition dependent rare earth element (REE) partitioning between coexisting orthopyroxene and clinopyroxene. This trace element based two-pyroxene thermometer is built on two parameterized lattice strain models for REE partitioning between pyroxene and basaltic melt that were independently calibrated using data from pyroxene-melt partitioning experiments (Sun and Liang, 2012; Yao et al., 2012). By treating REE and Y as a group in temperature calculations, one can reduce analytical uncertainties in trace element analysis through least squares inversion of orthopyroxene-clinopyroxene partitioning data, and identify and exclude variations induced by secondary or metasomatic processes. For convenience, a simple robust regression program is provided for temperature inversion. Application of the REE-in-two-pyroxene thermometer to well-equilibrated spinel lherzolite and harzburgite xenoliths from the continental lithosphere demonstrates the internal consistency of the two pyroxene-melt REE partitioning models and the trace and major element based pyroxene thermometers: temperatures derived from the REE-in-two-pyroxene thermometer agree very well with temperatures calculated using major element based pyroxene thermometers. Applications of the REE-in-two-pyroxene thermometer to abyssal peridotites and mafic cumulates reveal a significant difference in the calculated temperatures between the REE and major element based pyroxene thermometers: temperatures derived from the REE-in-two-pyroxene thermometer are consistently higher than those derived from the major element based pyroxene thermometers. This discrepancy in temperature likely results from a difference in diffusion rate and hence closure temperature between the 2+ and 3+ cations in the pyroxenes. An independently calibrated REE-in-two-pyroxene thermometer may offer new insight into the thermal history of mafic and ultramafic rocks from the upper mantle and lower crust. Author Affiliation: Department of Geological Sciences, Brown University, Providence, RI 02912, United States Article History: Received 11 May 2012; Accepted 18 October 2012 Article Note: (miscellaneous) Associate editor: Michael Toplis
    Keywords: Spinel Group -- Analysis ; Xenoliths -- Analysis ; Basalt -- Analysis ; Lithosphere -- Analysis ; Mantle (Geology) -- Analysis ; Measuring Instruments -- Analysis
    ISSN: 0016-7037
    Source: Cengage Learning, Inc.
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  • 4
    Language: English
    In: Electrochimica Acta, Jan 15, 2012, Vol.60, p.456(8)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.electacta.2011.11.103 Byline: Yan Liang, Hongyun Liu, Kaina Zhang, Naifei Hu Keywords: Glucose oxidase; Multi-switchable bioelectrocatalysis; Ferrocenedicarboxylic acid; Poly(N,N-diethylacrylamide); Poly(4-vinylpyridine) Abstract: a* P(DEA-co-4VP) copolymer films containing GOD are polymerized on electrode surface. a* The one-step polymerization is simple and takes only 20min at room temperature. a* CV response of Fc(COOH).sub.2 at film electrodes is sensitive to pH, T, and c.sub.sulfate. a* Based on this, the triply switchable bioelectrocatalysis of glucose can be realized. Author Affiliation: Department of Chemistry, Beijing Normal University, Beijing 100875, PR China Article History: Received 19 September 2011; Revised 21 November 2011; Accepted 25 November 2011
    Keywords: Glucose ; Copolymers ; Oxidases ; Polymerization ; Sulfates
    ISSN: 0013-4686
    Source: Cengage Learning, Inc.
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  • 5
    Language: English
    In: Journal of Hazardous Materials, Dec 15, 2011, Vol.197, p.311(9)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jhazmat.2011.09.093 Byline: Liang Yan, George A. Sorial Keywords: Activated carbon; Adsorption; Chemical activation; Oligomerization; Pore size distribution Abstract: a* BET surface area and microporosity is significantly influenced by the activation process. a* Microporosity is significantly affected by activation temperature and KOH:coal ratio. a* High degree of microporosity is more important than high BET surface area. a* Oligomerization of phenolics is hampered by controlling the activation process for obtaining high microporosity. Author Affiliation: School of Energy, Environmental, Biological, and Medical Engineering, University of Cincinnati, Cincinnati, OH 45221-0071, United States Article History: Received 15 June 2011; Revised 12 August 2011; Accepted 23 September 2011
    Keywords: Coal Industry ; Oligomers ; Adsorption ; Bituminous Coal
    ISSN: 0304-3894
    Source: Cengage Learning, Inc.
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  • 6
    Language: English
    In: Water Research, 01 May 2013, Vol.47(7), pp.2572-2582
    Description: Saturated sand-packed column experiments were conducted to investigate the influence of physicochemical factors on the transport and retention of surfactant stabilized silver nanoparticles (AgNPs). The normalized concentration in breakthrough curves (BTCs) of AgNPs increased with a decrease in solution ionic strength (IS), and an increase in water velocity, sand grain size, and input concentration ( ). In contrast to conventional filtration theory, retention profiles (RPs) for AgNPs exhibited uniform, nonmonotonic, or hyperexponential shapes that were sensitive to physicochemical conditions. The experimental BTCs and RPs with uniform or hyperexponential shape were well described using a numerical model that considers time- and depth-dependent retention. The simulated maximum retained concentration on the solid phase ( ) and the retention rate coefficient ( ) increased with IS and as the grain size and/or decreased. The RPs were more hyperexponential in finer textured sand and at lower because of their higher values of . Conversely, RPs were nonmonotonic or uniform at higher and in coarser sand that had lower values of , and tended to exhibit higher peak concentrations in the RPs at lower velocities and at higher solution IS. These observations indicate that uniform and nonmonotonic RPs occurred under conditions when was approaching filled conditions. Nonmonotonic RPs had peak concentrations at greater distances in the presence of excess amounts of surfactant, suggesting that competition between AgNPs and surfactant diminished close to the column inlet. The sensitivity of the nonmonotonic RPs to IS and velocity in coarser textured sand indicates that AgNPs were partially interacting in a secondary minimum. However, elimination of the secondary minimum only produced recovery of a small portion (〈10%) of the retained AgNPs. These results imply that AgNPs were largely irreversibly interacting in a primary minimum associated with microscopic heterogeneity. ► The presence of surfactant affected the shape of the retention profiles (RPs). ► RPs transitioned from hyperexponential, to nonmonotonic, and then to uniform. ► Nanoparticles mainly irreversibly interacted with microscopic heterogeneity.
    Keywords: Stabilized Silver Nanoparticles ; Saturated Porous Media ; Time- and Depth-Dependent Retention ; Surfactant ; Competitive Attachment ; Engineering
    ISSN: 0043-1354
    E-ISSN: 1879-2448
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  • 7
    Language: English
    In: Geochimica et Cosmochimica Acta, 2010, Vol.74(1), pp.321-339
    Description: Simple models for trace element fractionation during concurrent melting and melt migration in an upwelling steady-state mantle were developed. Based on petrologic considerations, we divided the mantle column into two regions: a single-lithology lower region that consists of partially molten garnet and spinel lherzolites and a double-lithology upper region where high-porosity dunite channels or melt-filled fractures are embedded in a porous lherzolite/harzburgite matrix. Analytical solutions for the case of a constant and uniform relative melting suction rate and a linearly variable relative melt suction rate were obtained. Key parameters and the first order characteristics of melting and melt migration in a 1-D steady-state mantle column were examined through forward calculations and Monte Carlo simulations. Melting in the upwelling single-lithology column is equivalent to non-modal batch melting, whereas melting and melt migration in the double-lithology region can be viewed as a nonlinear combination of batch melting and fractional melting, depending on the amount of melt extracted to the channel. The degree of melting ( ), the degree of melting at the depth of melt-channel initiation ( ) and the relative rate of melt suction are important in controlling the extent of depletion of the incompatible trace element in the matrix. Spatially variable affects the abundance of an incompatible trace element in the melt and residual solid the most in near fractional melting. There is a strong nonlinear trade off among the three parameters. Given , it is possible to constrain and from incompatible trace element abundances in residual peridotite. To explore the dynamics of melt migration in the mantle, we used the two melting models developed in this study and published REE and Y abundances in diopside in abyssal peridotites from the Central Indian Ridge to infer their melting and melt migration history. Overall, the degrees of melting inferred from the trace element data are not sensitive to the value of used in the inversion and ranges from 10% to 15%. The relative rate of melt suction depends slightly on the choice of and ranges from 0.85 to 1.0 for = 0.05 and 0.75 to 0.97 for = 0. Further, the estimated is inversely correlated with , a robust feature independent of the choice of . The upward decrease of in an upwelling mantle column can be understood in terms of melt focusing in the lower part of the double-lithology region. And finally, given and , we found that the permeability and porosity of the lherzolite/harzburgite matrix also increase as a function of in the melting column, with melt fractions ranging from 0.2% to 0.7% for a grain size of 5 mm.
    Keywords: Geology
    ISSN: 0016-7037
    E-ISSN: 1872-9533
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  • 8
    Language: English
    In: Journal of Power Sources, March 15, 2014, Vol.250, p.128(6)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jpowsour.2013.10.085 Byline: Liang Yan, Shikui Yao, Jinfa Chang, Changpeng Liu, Wei Xing Abstract: A novel Pd-based catalyst for formic acid electrooxidation (FAEO) was prepared by annealing commercial Pd/C catalyst under the O.sub.2 atmosphere at 100 [degrees]C, which exhibits excellent catalytic activity and stability for FAEO due to introduction of Pd oxides/hydrous oxides (POHOs). The catalytic activity of the as-prepared catalyst towards FAEO is 1.86 times of the commercial Pd/C catalyst in 0.5 M H.sub.2SO.sub.4 + 0.5 M HCOOH solution. Chronoamperometric curves show obvious improvement of the as-prepared catalyst electrocatalytic stability for FAEO. It is confirmed that POHOs can provide the required oxygen species for intermediate CO oxidation during the oxidation process of formic acid. Author Affiliation: (a) State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, 5625 Renmin Street, Changchun 130022, PR China (b) Laboratory of Advanced Power Sources, Changchun Institute of Applied Chemistry, 5625 Renmin Street, Changchun 130022, PR China (c) University of Chinese Academy of Sciences, Beijing, PR China Article History: Received 3 May 2013; Revised 15 October 2013; Accepted 19 October 2013
    Keywords: Palladium ; Palladium Catalysts ; Oxides ; Organic Acids ; Electrochemical Reactions ; Formic Acid
    ISSN: 0378-7753
    Source: Cengage Learning, Inc.
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  • 9
    Language: English
    In: Materials Letters, April 15, 2013, Vol.97, p.4(4)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.matlet.2013.01.093 Byline: Yan Liang, Yusi Lai, Dong Li, Bin He, Zhongwei Gu Keywords: 9-Nitro-20(S)-camptothecin; Polymeric micelle; Drug delivery; Cinnamic acid Abstract: 9-Nitro-20(S)-camptothecin (9-NC) is a broad-spectrum anticancer drug but its application was limited by its poor solubility in aqueous medium. Novel polymeric micelles were developed for 9-NC delivery. The micelles were fabricated from the self-assembly of amphiphiles with cinnamic acid (CIN) as lipohilic moiety and methoxy poly(ethylene glycol) (mPEG) as hydrophilic segment. The micelles were nontoxic to NIH 3T3 fibroblasts. 9-NC was trapped efficiently in mPEG-DCIN micelles. The release of 9-NC from the micelles with one cinnamic acid molecule as lipophilic moiety (mPEG-CIN) was much faster than that from the micelles with two cinnamic acid molecules as lipophilic moiety (mPEG-DCIN). The in vitro anticancer inhibition study demonstrated that the anticancer activity of 9-NC loaded mPEG-DCIN micelles was much better than that of 9-NC loaded mPEG-CIN micelles. Author Affiliation: National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, China Article History: Received 19 October 2012; Accepted 20 January 2013
    Keywords: Drug Delivery Systems ; Ethylene Glycols
    ISSN: 0167-577X
    Source: Cengage Learning, Inc.
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  • 10
    Language: English
    In: Geochimica et Cosmochimica Acta, 15 January 2016, Vol.173, pp.181-197
    Description: Disequilibrium melting arises when the kinetics of chemical exchange between a residual mineral and partial melt is sluggish compare to the rate of melting. To better understand the role of a finite crystal–melt exchange rate on trace element fractionation during mantle melting, we have developed a disequilibrium melting model for partial melting in an upwelling steady-state column. We use linear kinetics to approximate crystal–melt mass exchange rate and obtain simple analytical solutions for cases of perfect fractional melting and batch melting. A key parameter determining the extent of chemical disequilibrium during partial melting is an element specific dimensionless ratio ( ) defined as the melting rate relative to the solid–melt chemical exchange rate for the trace element of interest. In the case of diffusion in mineral limited chemical exchange, is inversely proportional to diffusivity of the element of interest. Disequilibrium melting is important for the trace element when is comparable to or greater than the bulk solid–melt partition coefficient for the trace element ( ). The disequilibrium fractional melting model is reduced to the equilibrium perfect fractional melting model when is much smaller than . Hence highly incompatible trace elements with smaller mobilities in minerals are more susceptible to disequilibrium melting than moderately incompatible and compatible trace elements. Effect of chemical disequilibrium is to hinder the extent of fractionation between residual solid and partial melt, making the residual solid less depleted and the accumulated melt more depleted in incompatible trace element abundances relative the case of equilibrium melting. Application of the disequilibrium fractional melting model to REE and Y abundances in clinopyroxene in abyssal peridotites from the Central Indian Ridge and the Vema Lithospheric Section, Mid-Atlantic Ridge revealed a positive correlation between the disequilibrium parameter and the degree of melting, which can be explained by an increase in melting rate and a decrease in REE diffusion rate in the upper part of the melting column. Small extent of disequilibrium melting for LREE and equilibrium melting for HREE in the upper part of the melting column can explain the elevated LREE abundances or spoon-shaped REE patterns in clinopyroxene in more refractory abyssal peridotites. The latter has often been attributed to melt refertilization.
    Keywords: Geology
    ISSN: 0016-7037
    E-ISSN: 1872-9533
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