Spatial imaging of Zn and other elements in Huanglongbing-affected grapefruit by synchrotron-based micro X-ray fluorescence investigation

Huanglongbing (HLB) is a highly destructive, fast-spreading disease of citrus, causing substantial economic losses to the citrus industry worldwide. Nutrient levels and their cellular distribution patterns in stems and leaves of grapefruit were analysed after graft-inoculation with lemon scions containing 'Candidatus Liberibacter asiaticus' (Las), the heat-tolerant Asian type of the HLB bacterium. After 12 months, affected plants showed typical HLB symptoms and significantly reduced Zn concentrations in leaves. Micro-XRF imaging of Zn and other nutrients showed that preferential localization of Zn to phloem tissues was observed in the stems and leaves collected from healthy grapefruit plants, but was absent from HLB-affected samples. Quantitative analysis by using standard references revealed that Zn concentration in the phloem of veins in healthy leaves was more than 10 times higher than that in HLB-affected leaves. No significant variation was observed in the distribution patterns of other elements such as Ca in stems and leaves of grapefruit plants with or without graft-inoculation of infected lemon scions. These results suggest that reduced phloem transport of Zn is an important factor contributing to HLB-induced Zn deficiency in grapefruit. Our report provides the first in situ, cellular level visualization of elemental variations within the tissues of HLB-affected citrus. © 2014 © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology

Rasta Resin-TBD-Catalyzed γ-Selective Morita–Baylis–Hillman Reactions of α,γ-Disubstituted Allenones

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Which group velocity of light in a dispersive medium?

The interaction between a light pulse, traveling in air, and a generic linear, non-absorbing and dispersive structure is analyzed. It is shown that energy conservation imposes a constraint between the group velocities of the transmitted and reflected light pulses. It follows that the two fields propagate with group velocities depending on the dispersive properties of the environment (air) and on the transmission properties of the optical structure, and are one faster and the other slower than the incident field. In other words, the group velocity of a light pulse in a dispersive medium is reminiscent of previous interactions. One example is discussed in detail.Comment: To be submitted on PR

An adaptive interpolating MLS based response surface model applied to design optimizations of electromagnetic devices

Author name used in this publication: S. L. HoAuthor name used in this publication: S. Y. Yang2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Water compatible resin for separation and recovery of dissolved precious metals

Trace Contaminants in Water: Genesis, Rapid Detection and Sustainable Removal Processes: abstract no. 353fOpen URL - http://apps.aiche.org/proceedings/Abstract.aspx?PaperID=119742The value of precious metals such as gold to be recovered in the industrial effluents within Pearl River Delta area is over HK$20 million per annual. Furthermore, with the expected tightening of environmental legislation and enforcement in the Mainland China, there is a growing need of effluent treatment technology. Traditionally, ion-exchange resin, polymer ultra-filtration and micro-emulsion are applied in the treatment of plating effluents. However, they all have different weaknesses. Many reports have been published for the separation using aqueous biphasic system. Based on this methodology, polystyrene-grafted-polyglycidol (PS-PG), a water-compatible polymer was synthesized. This type of polymer can be used for gold or silver extraction. After extraction, the recovery of metal can be achieved by direct electro-deposition or reverse extraction using sodium cyanide.postprintThe 2008 AIChE Annual Meeting (AIChE 100), Philadelphia, PA., 16-21 November 2008. In Conference Proceedings, 2008, p. 1-

A combined wavelet-FE method for transient electromagnetic-field computations

Author name used in this publication: S. Y. YangAuthor name used in this publication: S. L. HoAuthor name used in this publication: G. Z. Ni2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Scaling in the Lattice Gas Model

A good quality scaling of the cluster size distributions is obtained for the Lattice Gas Model using the Fisher's ansatz for the scaling function. This scaling identifies a pseudo-critical line in the phase diagram of the model that spans the whole (subcritical to supercritical) density range. The independent cluster hypothesis of the Fisher approach is shown to describe correctly the thermodynamics of the lattice only far away from the critical point.Comment: 4 pages, 3 figure

An improved tabu-based vector optimal algorithm for design optimizations of electromagnetic devices

Author name used in this publication: S. Y. YangAuthor name used in this publication: S. L. HoAuthor name used in this publication: J. M. MachadoAuthor name used in this publication: Edward W. C. Lo2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Star formation histories and evolution of 35 brightest E+A galaxies from SDSS DR5

We pick out the 35 brightest galaxies from Goto's E+A galaxies catalogue which are selected from the Sloan Digital Sky Survey Data Release 5. The spectra of E+As are prominently characterized by the strong Balmer absorption lines but little [Oii] or H_alpha emission lines. In this work we study the stellar populations of the sample galaxies by fitting their spectra using ULySS, which is a robust full spectrum fitting method. We fit each of the sample with 1-population (a single stellar population-a SSP) and 3-population (3 SSPs) models, separately. By 1-population fits, we obtain SSP-equivalent ages and metallicities which correspond to the `luminosity-weighted' averages. By 3-population fits, we divide components into three groups in age (old stellar population-OSP, intermediate-age stellar population-ISP, and young stellar population-YSP), and then get the optimal age, metallicity and population fractions in both mass and light for OSP, ISP and YSP. During the fits, both Pegase.HR/Elodie3.1 and Vazdekis/Miles are used as two independent population models. The two models result in generally consistent conclusions as follows: for all the sample galaxies, YSPs (< 1Gyr) make important contributions to the light. However, the dominant contributors to mass are OSPs. We also reconstruct the smoothing star formation histories (SFHs) by giving star formation rate (SFR) versus evolutionary age. In addition, we fit the E+A sample and 34 randomly selected elliptical galaxies with 2-population (2 SSPs) model. We obtain the equivalent age of old components for each of the E+A sample and elliptical galaxies. By comparison, the old components of E+As are statistically much younger than those of ellipticals. From the standpoint of the stellar population age, this probably provides an evidence for the proposed evolutionary link from E+As to early-types (E/S0s).Comment: 16 pages, 9 figures, Accepted for publication on MNRA

Novel Scaling Behavior for the Multiplicity Distribution under Second-Order Quark-Hadron Phase Transition

Deviation of the multiplicity distribution $P_q$ in small bin from its Poisson counterpart $p_q$ is studied within the Ginzburg-Landau description for second-order quark-hadron phase transition. Dynamical factor $d_q\equiv P_q/p_q$ for the distribution and ratio $D_q\equiv d_q/d_1$ are defined, and novel scaling behaviors between $D_q$ are found which can be used to detect the formation of quark-gluon plasma. The study of $d_q$ and $D_q$ is also very interesting for other multiparticle production processes without phase transition.Comment: 4 pages in revtex, 5 figures in eps format, will be appeared in Phys. Rev.