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Campbell SD, O'connell AK, Menon S, Su Q, Grobe R. Light scattering regimes along the optical axis in turbid media. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:061909. [PMID: 17280098 DOI: 10.1103/physreve.74.061909] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Indexed: 05/13/2023]
Abstract
We inject an angularly collimated laser beam into a scattering medium of a nondairy creamer-water solution and examine the distribution of the scattered light along the optical axis as a function of the source-detector spacing. The experimental and simulated data obtained from a Monte Carlo simulation suggest four regimes characterizing the transition from unscattered to diffusive light. We compare the data also with theoretical predictions based on a first-order scattering theory for regions close to the source, and with diffusionlike theories for larger source-detector spacings. We demonstrate the impact of the measurement process and the effect of the unavoidable absorption of photons by the detection fiber on the light distribution inside the medium. We show that the range of validity of these theories can depend on the experimental parameters such as the diameter and acceptance angle of the detection fiber.
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Lamb KD, Menon S, Su Q, Grobe R. Nonperturbative retrieval of the scattering strength in one-dimensional media. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:061903. [PMID: 17280092 DOI: 10.1103/physreve.74.061903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Revised: 09/07/2006] [Indexed: 05/13/2023]
Abstract
We examine several approaches on how to use the transmission and reflection amplitudes as functions of the modulation frequency of the laser's intensity to reconstruct the position-dependent scattering coefficient for a simple turbid medium. We explore the region where the contrast between the coefficient and its spatially averaged value is large enough such that perturbative methods fail. We show that in the case of a transillumination geometry, the knowledge of the transmission profile alone is not sufficient for unique image reconstruction, whereas the reflection spectrum allows for a complete inversion. We demonstrate the invertibility for media sampled at only a few positions.
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Wu Z, Shi J, Wang J, Gong M, Su Q. A novel blue-emitting phosphor LiSrPO4:Eu2+ for white LEDs. J SOLID STATE CHEM 2006. [DOI: 10.1016/j.jssc.2006.04.030] [Citation(s) in RCA: 224] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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79
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Hinderliter B, Croll S, Tallman D, Su Q, Bierwagen G. Interpretation of EIS data from accelerated exposure of coated metals based on modeling of coating physical properties. Electrochim Acta 2006. [DOI: 10.1016/j.electacta.2005.12.047] [Citation(s) in RCA: 202] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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80
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Mathew M, Tan L, Su Q, Yang X, Baxter M, Senior E. Bioremediation of 6 % [w/w] Diesel-Contaminated Mainland Soil in Singapore: Comparison of Different Biostimulation and Bioaugmentation Treatments. Eng Life Sci 2006. [DOI: 10.1002/elsc.200620119] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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81
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Menon S, Su Q, Grobe R. Velocity half-sphere model for multiple light scattering in turbid media. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 72:041910. [PMID: 16383423 DOI: 10.1103/physreve.72.041910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Indexed: 05/05/2023]
Abstract
We extend the traditional diffusion theory by distinguishing between the energy radiance in the forward and backward directions at each point in space. This approach leads to a new effective source for the diffusion equation that is nonzero for an anisotropic light source. It differs significantly from the diffusion theory for short source-detector spacings. We derive an analytical solution for the two lowest-order velocity moments of the radiance.
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82
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Chen Z, Li B, Miao M, Yang G, Yin J, Su Q. Simultaneous Determination of Palladium, Platinum and Rhodium by On-Line Column Enrichment and HPLC with 4-Hydroxy-1-Naphthalthiorhodanine as Pre-Column Derivatization Reagents. Mikrochim Acta 2005. [DOI: 10.1007/s00604-005-0385-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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83
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Krekora P, Cooley K, Su Q, Grobe R. Creation dynamics of bound States in supercritical fields. PHYSICAL REVIEW LETTERS 2005; 95:070403. [PMID: 16196767 DOI: 10.1103/physrevlett.95.070403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Indexed: 05/04/2023]
Abstract
Using space-time resolved solutions to relativistic quantum field theory, we analyze the electron-positron creation process from vacuum in the long-time regime in which multiple pairs are produced. We find that for a supercritical potential of finite extension, the time dependence of the production rate of pairs is described by four distinct regimes that have their direct counterparts in the time evolved spatial density of the particles. These regimes include the shape-invariant birth process, an entanglement-induced reduction of interference, a recurrent Pauli suppression of pair production induced by electron-potential scattering, and finally a production halt associated with a population of supercritical and a partial population of subcritical bound states.
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84
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Menon S, Su Q, Grobe R. Generalized diffusion solution for light scattering from anisotropic sources. OPTICS LETTERS 2005; 30:1542-4. [PMID: 16007801 DOI: 10.1364/ol.30.001542] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The traditional diffusion theory, often used for isotropic sources, becomes inaccurate at short source-detector spacings and cannot be applied to media with large absorption or with small scattering strengths. We show that for any type of source anisotropy, a Green's-function-based procedure can remove these limitations. The accuracy of the new approach is examined through a comparison with the numerical solution to the radiative transfer equation.
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85
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Menon S, Su Q, Grobe R. Determination of g and mu using multiply scattered light in turbid media. PHYSICAL REVIEW LETTERS 2005; 94:153904. [PMID: 15904148 DOI: 10.1103/physrevlett.94.153904] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2004] [Indexed: 05/02/2023]
Abstract
We propose an inversion scheme to reconstruct the scattering coefficient mu and the anisotropy factor g that characterize the optical properties of a turbid medium. It is based on a theory for the scattering of light inside the medium from an angularly collimated light source. We demonstrate the feasibility of this method using light scattering data obtained from a Monte Carlo simulation.
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86
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Youil R, Su Q, Toner TJ, Szymkowiak C, Kwan WS, Rubin B, Petrukhin L, Kiseleva I, Shaw AR, DiStefano D. Comparative study of influenza virus replication in Vero and MDCK cell lines. J Virol Methods 2005; 120:23-31. [PMID: 15234806 DOI: 10.1016/j.jviromet.2004.03.011] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2003] [Revised: 03/25/2004] [Accepted: 03/25/2004] [Indexed: 11/25/2022]
Abstract
The choice of a cell line for the production of influenza vaccines is determined by how well the virus is able to replicate and how easily the cell line can be maintained. Madin-Darby canine kidney (MDCK) cells have long been known to successfully support influenza growth. Vero cells are also another well studied candidate cell line. In this work, we have compared these two cell lines for their ability to propagate type A and type B cold-adapted and wild type influenza viruses. The growth of these viruses has been measured as plaque forming units (via plaque assay) as well as viral particle formation (via a novel quantitative RT-PCR assay) to assess the suitability of these cell lines to support the development of live attenuated influenza vaccines. The novel qRT-PCR assay outlined in this work was demonstrated to be an efficient, sensitive and reproducible method for measuring wild type (wt) and cold-adapted (ca) influenza strains. Replicates of six per sample consistently showed an average variation around +/-10%. In this study we have also found qRT-PCR to be a useful method for differentiating between wt and ca influenza strains based on their differing growth characteristics at varying temperatures. This can subsequently be used to assess reassortants prepared from ca donor strains for the purposes of live viral vaccine development. For type A and B influenza viruses studied in this work, MDCK cells supported a more rapid viral growth (measured in terms of genome copies) compared with Vero cells. For the type A viruses studied here, the genome copies: infectious unit (genome copy, gc:infectious unit, iu) ratio was found to be more favorable for Vero cells compared with MDCK cells. For the type B viruses studied in this work, the gc:iu was equivalent in both cell lines tested. Ultimately, however, the use of any new cell line would need to be approved by regulatory agencies prior to its commercial application.
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87
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Chen X, Yang XY, Wang ND, Ding C, Yang YJ, You ZJ, Su Q, Chen JH. Serum lysophosphatidic acid concentrations measured by dot immunogold filtration assay in patients with acute myocardial infarction. Scandinavian Journal of Clinical and Laboratory Investigation 2004; 63:497-503. [PMID: 14743959 DOI: 10.1080/00365510310003265] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In this study the relation between lysophosphatidic acid (LPA) and myocardial infarction was investigated, the typical and simplified methods for measuring serum LPA concentration by dot immunogold filtration assay (DIFA) based on a polyclonal antibody to LPA were developed, and serum LPA concentrations were measured in 31 patients with acute myocardial infarction (AMI) and 12 controls (blood donors) by DIFA. Serum LPA levels were raised more than twofold 8 h after the onset of AMI. Maximal elevation (10.43 mg/L) was found at 48-72 h following onset and remained higher than the control concentration (1.66 mg/L) 7 days after AMI. The rise in serum LPA concentration in AMI patients suggests that LPA might be involved in AMI-related pathophysiology in the cardiovascular system. The simplified DIFA developed in the present study for measuring serum LPA concentration is convenient and highly sensitive.
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88
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Krekora P, Su Q, Grobe R. Relativistic electron localization and the lack of Zitterbewegung. PHYSICAL REVIEW LETTERS 2004; 93:043004. [PMID: 15323758 DOI: 10.1103/physrevlett.93.043004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2003] [Indexed: 05/24/2023]
Abstract
Using space-time resolved solutions to relativistic quantum field theory we analyze the electron-positron pair creation process from vacuum. For early times the entangled electron-positron wave function can be obtained analytically. We show that there are, in principle, no limitations to the localization length of an electron and demonstrate that its spatial probability density can be much narrower than the Compton wavelength. We also find that quantum field theory prohibits the occurrence of Zitterbewegung for an electron.
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89
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Youil R, Kiseleva I, Kwan WS, Szymkowiak C, Toner TJ, Su Q, Klimov A, Rudenko L, Shaw AR. Phenotypic and genetic analyses of the heterogeneous population present in the cold-adapted master donor strain: A/Leningrad/134/17/57 (H2N2). Virus Res 2004; 102:165-76. [PMID: 15084398 DOI: 10.1016/j.virusres.2004.01.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2003] [Revised: 01/23/2004] [Accepted: 01/23/2004] [Indexed: 11/29/2022]
Abstract
For the past three decades the cold-adapted (ca) and temperature sensitive (ts) master donor strain, A/Leningrad/134/17/57 (H2N2) has been successfully used as the basis for the live attenuated reassortant influenza A vaccine. This donor strain was developed from A/Leningrad/134/57 (H2N2) wild-type (wt) virus following 17 passages in eggs at 25 degrees C. Our detailed investigation has revealed that the A/Leningrad/134/17/57 (Len/17) master donor stock is a mixed population comprised of numerous variants of the ca/ts Len/17 influenza virus. We have identified these variants to exhibit a broad range in their temperature sensitive phenotype when assayed on Madin-Darby canine kidney (MDCK) cells at 37 degrees C. A selection of these variant clones has been fully characterized by sequencing in order to understand the variability in the ts phenotype. This study has also addressed the feasibility of using cell culture technology for the propagation and subsequent manufacturing of the cold-adapted influenza vaccine (CAIV), particularly with respect to retaining the defined mutations that contribute toward the ca/ts phenotype.
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Kiseleva I, Su Q, Toner T, Szymkowiak C, Kwan WS, Kraiouchkine N, Rudenko L, Shaw A, Youil R. Development and evaluation of live influenza (LIV) cold-adapted reassortant vaccines in cell culture. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.ics.2004.02.158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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91
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Kiseleva I, Su Q, Toner TJ, Szymkowiak C, Kwan WS, Rudenko L, Shaw AR, Youil R. Cell-based assay for the determination of temperature sensitive and cold adapted phenotypes of influenza viruses. J Virol Methods 2004; 116:71-8. [PMID: 14715309 DOI: 10.1016/j.jviromet.2003.10.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The determination of temperature sensitive (ts) and cold adapted (ca) phenotype for influenza A and B strains has been conducted traditionally using embryonated chicken eggs. As attempts are made to move away from the use of eggs in the manufacturing process of influenza vaccines, it will become useful to develop cell-based assays to support cell culture-based vaccine production. In this study, MDCK cells have been evaluated as a tool for determining the ts and ca phenotypes associated with live attenuated influenza viruses. Direct comparisons were made of these phenotypes carried out in eggs. Reassortants made from the Russian live attenuated influenza donor strains A/Leningrad/134/17/57 (H2N2) and B/USSR/60/69 were prepared entirely in MDCK cells and their phenotypes evaluated using the MDCK cell-based assay. It is concluded that MDCK cells are more sensitive than eggs for the measurement of ts and ca phenotype of influenza viruses (particularly for influenza A) and they provide an alternative means for screening candidate reassortants prior to determining their genome composition.
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92
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Rutherford GH, Marsalli M, Su Q, Grobe R. Imaging in turbid media using modulation frequency scanning. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 68:066618. [PMID: 14754347 DOI: 10.1103/physreve.68.066618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2003] [Indexed: 11/07/2022]
Abstract
We propose an imaging scheme to detect an object inside a turbid medium using intensity modulated waves as a probe. We show how the new degree of freedom represented by the modulation frequency allows sufficient control to reconstruct the image from the scattered wave signal.
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93
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Krekora P, Su Q, Grobe R. Klein paradox in spatial and temporal resolution. PHYSICAL REVIEW LETTERS 2004; 92:040406. [PMID: 14995359 DOI: 10.1103/physrevlett.92.040406] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2003] [Indexed: 05/24/2023]
Abstract
Based on spatially and temporally resolved numerical solutions to the relativistic quantum field equations, we provide a resolution to the controversial issue of how an incoming electron scatters off a supercritical potential step and how the electron-positron pair production is affected by this collision. The treatment of the problem as a correlated three-particle problem suggests revealing insight into the process.
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94
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Palme AE, Su Q, Palsson S, Lascoux M. Extensive sharing of chloroplast haplotypes among European birches indicates hybridization among Betula pendula, B. pubescens and B. nana. Mol Ecol 2004; 13:167-78. [PMID: 14653797 DOI: 10.1046/j.1365-294x.2003.02034.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Extensive sharing of chloroplast haplotypes among the silver birch, Betula pendula Roth., the downy birch, B. pubescens Ehrh., and the dwarf birch, B. nana L., was discovered using polymerase chain reaction-restriction fragment length polymporphism markers. The geographical component of the genetic variation was stronger than the species component: the species were not significantly different while 11% of the variation could be attributed to differentiation between the two main regions studied, Scandinavia and western Russia. All haplotypes occurring in more than 2% of the individuals were shared among the species and the introgression ratios were quite large: 0.79 between B. pubescens and B. pendula and 0.67 between B. pubescens and B. nana. The data also indicate that B. pendula individuals are more similar to sympatric B. pubescens than to B. pendula individuals from nearby forests. However, this trend is not as pronounced when B. pubescens is considered, suggesting that introgression is not symmetrical. The haplotype sharing among the three Betula species is most likely caused by hybridization and subsequent cytoplasmic introgression.
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95
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Menon S, Su Q, Grobe R. Bridging the microscopic and macroscopic theories for light reflected from disordered plane-parallel dielectric slabs. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2003; 68:046614. [PMID: 14683072 DOI: 10.1103/physreve.68.046614] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2003] [Indexed: 05/24/2023]
Abstract
For a system of randomly arranged plane-parallel dielectric layers with randomly varying index of refraction and width, we compare the reflection coefficient derived from the Maxwell equations with that of the Boltzmann theory. For a strictly monochromatic field this coefficient is an oscillatory function of the laser frequency. We show how suitable frequency or ensemble averaging permits a comparison of the two theories. The calculation of the usual Boltzmann scattering coefficient from microscopic parameters can be improved to permit a better agreement with the exact Maxwell data.
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96
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Pan BC, Xiong Y, Su Q, Li AM, Chen JL, Zhang QX. Role of amination of a polymeric adsorbent on phenol adsorption from aqueous solution. CHEMOSPHERE 2003; 51:953-962. [PMID: 12697186 DOI: 10.1016/s0045-6535(03)00038-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Adsorption of seven phenols, one aromatic carboxylic acid and one sulfonated aromatic acid from aqueous solution, by a hypercrosslinked polymeric adsorbent (CHA-111) and the derivative animated by dimethylamine was compared. The results of different adsorption isotherms indicated that amino group on the polymeric matrix played a significant role on adsorption of almost all the employed compounds. For most employed compounds adsorption capacities increase to different degree and significantly for those with lower value of pK(a). It may be attributed to the enhanced adsorbent-adsorbate interaction for amino group introduced on the polymeric matrix. The empirical Freundlich isotherm equation was employed to interpret the adsorbent-adsorbate interaction. The adsorption enthalpy change indicated the uptake of phenols on MCH-111 to be an enhanced physical adsorption because of the hydrogen-bonding interaction. Adsorption kinetic study of phenols on CHA-111 and MCH-111 was also conducted and amino group on the matrix will reduce the adsorption rate for change of pore size distribution and loss of macroprous volume as well as the hydration effect on the surface partly.
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97
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Gao J, Liu Y, Wang X, Yu D, Su Q, Liu C. [Experimental therapy of Pagumogonimus skrjabini infection in rats with triclabendazole]. ZHONGGUO JI SHENG CHONG XUE YU JI SHENG CHONG BING ZA ZHI = CHINESE JOURNAL OF PARASITOLOGY & PARASITIC DISEASES 2003; 17:35-8. [PMID: 12563814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
AIM To observe the therapeutic effect of triclabendazole in rats infected with Pagumogonimus skrjabini. METHODS Metacercariae of P. skrjabini were isolated from crabs (Sinopotamon) collected from two endemic areas (Weiyuan County of Sichuan Province and Wansheng District of Chongqing Municipality). Wistar rats were each infected intraperitoneally with metacercariae. One month and two months after infection, the infected rats were treated with triclabendazole at the total dosage of 300 mg/kg over 2 days, 450 mg/kg over 3 days and 600 mg/kg over 3 days, respectively. RESULTS The worm reduction rates were 50%, 80% and 87% respectively one month after completion of tretment. Dead worms (about 1 mm size) recovered from the muscles, liver, abdominal cavity, chest cavity and lungs were signicantly diminished in size and weight in comparison with those of the control group. Many large (about 1 cm) black-colored distended worm cysts usually with two adult worms and many eggs were found in the lungs of the control rats. Most worm cysts in the treated groups of rats were found to be atrophied, changing into hemorrhagic-necrotic patches. CONCLUSION Triclabendazole is highly active against P. skrjabini in rats.
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98
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Menon S, Su Q, Grobe R. Iterative approach to Maxwell equations for dielectric media of spatially varying refractive index. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2003; 67:046619. [PMID: 12786521 DOI: 10.1103/physreve.67.046619] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2002] [Indexed: 05/24/2023]
Abstract
We propose an iterative method to solve the Maxwell equations for a one-dimensional model system with spatially varying permittivity. We construct solutions that are iterative in the scattering order, equivalent to the number of scattering events along the forward and backward directions. A numerical implementation of this approach is also presented.
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99
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Palmé AE, Su Q, Rautenberg A, Manni F, Lascoux M. Postglacial recolonization and cpDNA variation of silver birch, Betula pendula. Mol Ecol 2003; 12:201-12. [PMID: 12492888 DOI: 10.1046/j.1365-294x.2003.01724.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chloroplast PCR-RFLP markers were used to reconstruct the history of the silver birch, Betula pendula Roth, in Europe since the last glacial maximum (LGM). In birch, fossil pollen maps do not reveal a clear chronological sequence of postglacial spread. If anything, the pollen record suggests that most of Europe was recolonized by birches as early as 10000 bp, probably from populations that remained close to the ice sheets during the LGM. The geographical distribution of haplotypes supports a scenario of early colonization. Two of the 13 haplotypes that were observed are common, representing 35% and 49% of the total sample, respectively. Although one of the common haplotypes is predominant in the NW and the other in the SE, both are present throughout most of the investigated geographical area. Rare haplotypes are geographically restricted. The distribution of the haplotypes reveals five genetic boundaries between groups of haplotypes and allows us to infer patterns of postglacial recolonization. Europe was re-occupied by two main waves of recolonization: one eastern and one western, with origins at intermediate latitudes. Populations in the Iberian Peninsula and in Italy did not take part in the postglacial recolonization of Europe.
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100
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Su Q, Rowley KG, Itsiopoulos C, O'Dea K. Identification and quantitation of major carotenoids in selected components of the Mediterranean diet: green leafy vegetables, figs and olive oil. Eur J Clin Nutr 2002; 56:1149-54. [PMID: 12428183 DOI: 10.1038/sj.ejcn.1601472] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2001] [Revised: 03/08/2002] [Accepted: 03/11/2002] [Indexed: 01/10/2023]
Abstract
OBJECTIVE To characterize the carotenoid content of selected components of the Mediterranean diet commonly eaten by Greek migrants to Melbourne, a population group maintaining a traditional dietary regimen, and who exhibit relatively high circulating carotenoid concentrations and low cardiovascular disease mortality. DESIGN AND SPECIMENS: Opportunistic sampling of wild (sow thistle, amaranth, purslane and dandelion, collected from roadsides and home gardens) and commercially available (chicory, endive) green leafy vegetables and figs in season. Foods were selected on the basis that they are commonly eaten by Greek migrants but not by Anglo-Celtic persons, and had not previously been well-characterized with respect to their carotenoid contents. Extra virgin, cold-pressed olive oil and 'extra light' olive oil were obtained from commercial sources. Specimens were extracted with tetrahydrofuran (or chloroform:methanol for olive oil) and carotenoid contents were quantified using HPLC with UV detection. Two to six specimens of greens and figs were analysed. Dietary intake was assessed by food frequency questionnaire. RESULTS Wild green vegetables contained high concentrations of lutein (sow thistle>amaranth>purslane>dandelion) and beta-carotene (sow thistle>amaranth>purslane=dandelion). Sow thistle and amaranth contained lutein (15 and 13 mg/100 g, respectively) and beta-carotene (3.3 and 4.0 mg/100 g, respectively) at concentrations greater than that seen in the commercially available species of chicory and endive. Figs contained all major carotenoids appearing in plasma, albeit at low concentrations. Extra virgin cold-pressed olive oil contained substantial quantities of lutein and beta-carotene, but the more-refined 'extra light' olive oil did not. CONCLUSIONS These components of the traditional Mediterranean diet contribute to the higher circulating concentrations of carotenoids in Greek migrants compared to Anglo-Celtic Australians. SPONSORSHIP This study largely funded by the National Health and Medical Research Council of Australia (grant no. 974098). Extra virgin olive oil donated by Picuba Foods, Marrickville, NSW, Australia.
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