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Search Results: 1 - 10 of 530896 matches for " Eugene S. B. Zhang "
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Isolation and Evaluation of Oil-Producing Microalgae from Subtropical Coastal and Brackish Waters
David K. Y. Lim, Sourabh Garg, Matthew Timmins, Eugene S. B. Zhang, Skye R. Thomas-Hall, Holger Schuhmann, Yan Li, Peer M. Schenk
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0040751
Abstract: Microalgae have been widely reported as a promising source of biofuels, mainly based on their high areal productivity of biomass and lipids as triacylglycerides and the possibility for cultivation on non-arable land. The isolation and selection of suitable strains that are robust and display high growth and lipid accumulation rates is an important prerequisite for their successful cultivation as a bioenergy source, a process that can be compared to the initial selection and domestication of agricultural crops. We developed standard protocols for the isolation and cultivation for a range of marine and brackish microalgae. By comparing growth rates and lipid productivity, we assessed the potential of subtropical coastal and brackish microalgae for the production of biodiesel and other oil-based bioproducts. This study identified Nannochloropsis sp., Dunaniella salina and new isolates of Chlorella sp. and Tetraselmis sp. as suitable candidates for a multiple-product algae crop. We conclude that subtropical coastal microalgae display a variety of fatty acid profiles that offer a wide scope for several oil-based bioproducts, including biodiesel and omega-3 fatty acids. A biorefinery approach for microalgae would make economical production more feasible but challenges remain for efficient harvesting and extraction processes for some species.
NK Cells Promote Th-17 Mediated Corneal Barrier Disruption in Dry Eye
Xiaobo Zhang, Eugene A. Volpe, Niral B. Gandhi, Chris S. Schaumburg, Karyn F. Siemasko, Solherny B. Pangelinan, Scott D. Kelly, Adrian C. Hayday, De-Quan Li, Michael E. Stern, Jerry Y. Niederkorn, Stephen C. Pflugfelder, Cintia S. De Paiva
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0036822
Abstract: Background The conjunctiva contains a specialized population of lymphocytes that reside in the epithelium, named intraepithelial lymphocytes (IEL). Methodology/Principal Findings Here we characterized the IEL population prior to and after experimental desiccating stress (DS) for 5 or 10 days (DS5, DS10) and evaluated the effect of NK depletion on DS. The frequency of IELs in normal murine conjunctiva was CD3+CD103+ (~22%), CD3+γδ+ (~9.6%), CD3+NK+ (2%), CD3?NK+ (~4.4%), CD3+CD8α (~0.9%), and CD4 (~0.6%). Systemic depletion of NK cells prior and during DS led to a decrease in the frequency of total and activated DCs, a decrease in T helper-17+ cells in the cervical lymph nodes and generation of less pathogenic CD4+T cells. B6.nude recipient mice of adoptively transferred CD4+T cells isolated from NK-depleted DS5 donor mice showed significantly less corneal barrier disruption, lower levels of IL-17A, CCL20 and MMP-3 in the cornea epithelia compared to recipients of control CD4+T cells. Conclusions/Significance Taken together, these results show that the NK IELs are involved in the acute immune response to desiccation-induced dry eye by activating DC, which in turn coordinate generation of the pathogenic Th-17 response.
Disruption of TGF-β Signaling Improves Ocular Surface Epithelial Disease in Experimental Autoimmune Keratoconjunctivitis Sicca
Cintia S. De Paiva, Eugene A. Volpe, Niral B. Gandhi, Xiaobo Zhang, Xiaofen Zheng, John D. Pitcher, William J. Farley, Michael E. Stern, Jerry Y. Niederkorn, De-Quan Li, Richard A. Flavell, Stephen C. Pflugfelder
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0029017
Abstract: Background TGF-β is a pleiotropic cytokine that can have pro- or anti-inflammatory effects depending on the context. Elevated levels of bioactive TGF-β1 in tears and elevated TGF-β1mRNA transcripts in conjunctiva and minor salivary glands of human Sj?gren's Syndrome patients has also been reported. The purpose of this study was to evaluate the response to desiccating stress (DS), an experimental model of dry eye, in dominant-negative TGF-β type II receptor (CD4-DNTGFβRII) mice. These mice have a truncated TGF-β receptor in CD4+ T cells, rendering them unresponsive to TGF-β. Methodology/Principal Findings DS was induced by subcutaneous injection of scopolamine and exposure to a drafty low humidity environment in CD4-DNTGFβRII and wild-type (WT) mice, aged 14 weeks, for 5 days. Nonstressed (NS) mice served as controls. Parameters of ocular surface disease included corneal smoothness, corneal barrier function and conjunctival goblet cell density. NS CD4-DNTGFβRII at 14 weeks of age mice exhibited a spontaneous dry eye phenotype; however, DS improved their corneal barrier function and corneal surface irregularity, increased their number of PAS+ GC, and lowered CD4+ T cell infiltration in conjunctiva. In contrast to WT, CD4-DNTGFβRII mice did not generate a Th-17 and Th-1 response, and they failed to upregulate MMP-9, IL-23, IL-17A, RORγT, IFN-γ and T-bet mRNA transcripts in conjunctiva. RAG1KO recipients of adoptively transferred CD4+T cells isolated from DS5 CD4-DNTGFβRII showed milder dry eye phenotype and less conjunctival inflammation than recipients of WT control. Conclusions/Significance Our results showed that disruption of TGF-β signaling in CD4+ T cells causes paradoxical improvement of dry eye disease in mice subjected to desiccating stress.
A late origin of the extant eukaryotic diversity: divergence time estimates using rare genomic changes
Diana Chernikova, Sam Motamedi, Miklós Csür?s, Eugene V Koonin, Igor B Rogozin
Biology Direct , 2011, DOI: 10.1186/1745-6150-6-26
Abstract: We applied the genome-wide analysis of rare genomic changes associated with conserved amino acids (RGC_CAs) and used several independent techniques to obtain date estimates for the divergence of the major lineages of eukaryotes with calibration intervals for insects, land plants and vertebrates. The results suggest an early divergence of monocot and dicot plants, approximately 340 Mya, raising the possibility of plant-insect coevolution. The divergence of bilaterian animal phyla is estimated at ~400-700 Mya, a range of dates that is consistent with cladogenesis immediately preceding the Cambrian explosion. The origin of opisthokonts (the supergroup of eukaryotes that includes metazoa and fungi) is estimated at ~700-1,000 Mya, and the age of LECA at ~1,000-1,300 Mya. We separately analyzed the red algal calibration interval which is based on single fossil. This analysis produced time estimates that were systematically older compared to the other estimates. Nevertheless, the majority of the estimates for the age of the LECA using the red algal data fell within the 1,200-1,400 Mya interval.The inference of a "young LECA" is compatible with the latest of previously estimated dates and has substantial biological implications. If these estimates are valid, the approximately 1 to 1.4 billion years of evolution of eukaryotes that is open to comparative-genomic study probably was preceded by hundreds of millions years of evolution that might have included extinct diversity inaccessible to comparative approaches.This article was reviewed by William Martin, Herve Philippe (nominated by I. King Jordan), and Romain Derelle.Estimation of divergence dates for biological taxa from molecular data is a perilous exercise fraught by artifacts which become progressively more severe for events further in the past [1,2]. There are many factors that hamper molecular time estimates, especially for ancient events. Some of the most important problems are violations of the molecular clock, unc
Homoplasy in genome-wide analysis of rare amino acid replacements: the molecular-evolutionary basis for Vavilov's law of homologous series
Igor B Rogozin, Karen Thomson, Miklós Csür?s, Liran Carmel, Eugene V Koonin
Biology Direct , 2008, DOI: 10.1186/1745-6150-3-7
Abstract: We provide a direct estimate of the level of homoplasy caused by parallel changes and reversals among the RGC_CAMs using 462 alignments of orthologous genes from 19 eukaryotic species. It is shown that the impact of parallel changes and reversals on the results of phylogenetic inference using RGC_CAMs cannot explain the observed support for the Coelomata clade. In contrast, the evidence in support of the Ecdysozoa clade, in large part, can be attributed to parallel changes. It is demonstrated that parallel changes are significantly more common in internal branches of different subtrees that are separated from the respective common ancestor by relatively short times than in terminal branches separated by longer time intervals. A similar but much weaker trend was detected for reversals. The observed evolutionary trend of parallel changes is explained in terms of the covarion model of molecular evolution. As the overlap between the covarion sets in orthologous genes from different lineages decreases with time after divergence, the likelihood of parallel changes decreases as well.The level of homoplasy observed here appears to be low enough to justify the utility of RGC_CAMs and other types of RGCs for resolution of hard problems in phylogeny. Parallel changes, one of the major classes of events leading to homoplasy, occur much more often in relatively recently diverged lineages than in those separated from their last common ancestor by longer time intervals of time. This pattern seems to provide the molecular-evolutionary underpinning of Vavilov's law of homologous series and is readily interpreted within the framework of the covarion model of molecular evolution.This article was reviewed by Alex Kondrashov, Nicolas Galtier, and Maximilian Telford and Robert Lanfear (nominated by Laurence Hurst).With the rapid growth of the collection of sequenced genomes from diverse taxa, reconstruction of the evolutionary history of organisms on the basis of full-scale comparison of
A Hybrid Long-Distance Entanglement Distribution Protocol
Jonatan B. Brask,Ioannes Rigas,Eugene S. Polzik,Ulrik L. Andersen,Anders S. Sorensen
Physics , 2010, DOI: 10.1103/PhysRevLett.105.160501
Abstract: We propose a hybrid (continuous-discrete variable) quantum repeater protocol for distribution of entanglement over long distances. Starting from entangled states created by means of single-photon detection, we show how entangled coherent state superpositions, also known as `Schr\"odinger cat states', can be generated by means of homodyne detection of light. We show that near-deterministic entanglement swapping with such states is possible using only linear optics and homodyne detectors, and we evaluate the performance of our protocol combining these elements.
Features of Malus Law in the Region of X-Ray Radiation  [PDF]
Andrey N. Volobuev, Eugene S. Petrov, Eugene L. Ovchinnikov
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.37080
Abstract: The light propagation through system a polarizer-analyzer is investigated on the basis of quantum conceptions about the nature of light. It is shown, that Malus law based on principles of classical electrodynamics not completely takes into account all effects which can occur at the light propagation through system a polarizer-analyzer. The phenomenon of possible change of frequency of light in particular drops out, for example in the region of X-ray radiation. The deduction of Malus law based on quantum principles is given. For comparison the differential effective section of interaction of a photon and electron with take into account of rotation of a plane of polarization of a photon in Compton’s effect is found.
Thermal Electromagnetic Radiation of Rarefied Gas  [PDF]
Andrey N. Volobuev, Eugene S. Petrov, Eugene L. Ovchinnikov
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.43040
Abstract:

The Boltzmann kinetic equation for rarefied radiating gas is found. It is shown, that process of radiation is defined by excitation of atoms at their collision, and also spontaneous radiation of quantums at transition of electrons to the basic power level and the compelled radiation of quantums at collision of the excited atoms. It is shown, that distributions on velocities of the excited and not excited atoms submit to various laws. Distinctions in laws of distribution of the excited and not excited atoms define power parameters of radiating gas, and also a share of radiating molecules in gas.

Influence β-radioactive radiation on tissues of the organism  [PDF]
Andrey N. Volobuev, Eugene S. Petrov, Eugene L. Ovchinnikov
Natural Science (NS) , 2012, DOI: 10.4236/ns.2012.412A137
Abstract:

Research of interaction of β-radioactive radiation with biotissue of an organism is lead. It is shown, that during electrons moderation there is a brake electromagnetic radiation usually in an X-ray range. There are derivatives of the formulas in not relativistic and relativistic variant for a finding of dependence of a flux brake electromagnetic radiation from frequency, of charging number elements of a biotissue, of a parameter of efficiency braking of electrons, of initial intensity of a flux of electrons and initial energy of electrons, is given.

Role of the Reference Frame in Angular Photon Distribution at Electron-Positron Annihilation  [PDF]
Andrey N. Volobuev, Eugene S. Petrov, Eugene L. Ovchinnikov
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.56045
Abstract:

The reasons of angular photon distribution occurrence at electron-positron annihilation are considered. It is shown that angular photon distribution is consequence of Doppler’s effect in the reference frame of the electron and positron mass center. In the reference frame bound with moving electron the angular photon distribution is absent. But it is replaced by the Doppler’s shift of photons frequencies. The received results are applied to the analysis of a positron-emission tomograph work.

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