Role of scattering-factor anisotropy in electron, positron, and photon holography

We have studied the angular anisotropy in the scattering factor of electrons, positrons, and photons in solids. We show that as a function of angle, the maximum number of dips in the scattering factor's magnitude and jumps of near π in its phase are related to the angular momenta of the bound and resonance states of the potential. The effect of the scattering factor's anisotropy on low-energy electron and positron holographic wave-front reconstruction is discussed. Applying the variable-axis small-cone method, a good-quality reconstructed image is only possible within angular regions where the scattering factor is near isotropic. Thus the usable window for low-energy electron wave-front reconstruction is element dependent; the window size decreases as the atomic number increases. Positrons, on the other hand, are like photons and are not bound by the potential. For positrons or photons, there is no elemental dependence of the usable window and the entire backscattering regime is suitable for holographic reconstruction. We have established two rules that predict the maximum number of magnitude dips and phase jumps in the scattering factor for any element.published_or_final_versio

Proteomic analysis during larval development and metamorphosis of the spionid polychaete Pseudopolydora vexillosa

<p>Abstract</p> <p>Background</p> <p>While the larval-juvenile transition (metamorphosis) in the spionid polychaete <it>Pseudopolydora vexillosa </it>involves gradual morphological changes and does not require substantial development of juvenile organs, the opposite occurs in the barnacle <it>Balanus amphitrite</it>. We hypothesized that the proteome changes during metamorphosis in the spionids are less drastic than that in the barnacles. To test this, proteomes of pre-competent larvae, competent larvae (ready to metamorphose), and juveniles of <it>P. vexillosa </it>were compared using 2-dimensional gel electrophoresis (2-DE), and they were then compared to those of the barnacle.</p> <p>Results</p> <p>Unlike the significant changes found during barnacle metamorphosis, proteomes of competent <it>P. vexillosa </it>larvae were more similar to those of their juveniles. Pre-competent larvae had significantly fewer protein spots (384 spots), while both competent larvae and juveniles expressed about 660 protein spots each. Proteins up-regulated during competence identified by MALDI-TOF/TOF analysis included a molecular chaperon (calreticulin), a signal transduction regulator (tyrosin activation protein), and a tissue-remodeling enzyme (metallopeptidase).</p> <p>Conclusions</p> <p>This was the first time to study the protein expression patterns during the metamorphosis of a marine polychaete and to compare the proteomes of marine invertebrates that have different levels of morphological changes during metamorphosis. The findings provide promising initial steps towards the development of a proteome database for marine invertebrate metamorphosis, thus deciphering the possible mechanisms underlying larval metamorphosis in non-model marine organisms.</p

Phosphoproteome analysis during larval development and metamorphosis in the spionid polychaete Pseudopolydora vexillosa

<p>Abstract</p> <p>Background</p> <p>The metamorphosis of the spionid polychaete <it>Pseudopolydora vexillosa </it>includes spontaneous settlement onto soft-bottom habitats and morphogenesis that can be completed in a very short time. A previous study on the total changes to the proteome during the various developmental stages of <it>P. vexillosa </it>suggested that little or no <it>de novo </it>protein synthesis occurs during metamorphosis. In this study, we used multicolor fluorescence detection of proteins in 2-D gels for differential analysis of proteins and phosphoproteins to reveal the dynamics of post-translational modification proteins in this species. A combination of affinity chromatography, 2D-PAGE, and mass spectrometry was used to identify the phosphoproteins in pre-competent larvae, competent larvae, and newly metamorphosed juveniles.</p> <p>Results</p> <p>We reproducibly detected 210, 492, and 172 phosphoproteins in pre-competent larvae, competent larvae, and newly metamorphosed juveniles, respectively. The highest percentage of phosphorylation was observed during the competent larval stage. About 64 stage-specific phosphoprotein spots were detected in the competent stage, and 32 phosphoproteins were found to be significantly differentially expressed in the three stages. We identified 38 phosphoproteins, 10 of which were differentially expressed during metamorphosis. These phosphoproteins belonged to six categories of biological processes: (1) development, (2) cell differentiation and integrity, (3) transcription and translation, (4) metabolism, (5) protein-protein interaction and proteolysis, and (6) receptors and enzymes.</p> <p>Conclusion</p> <p>This is the first study to report changes in phosphoprotein expression patterns during the metamorphosis of the marine polychaete <it>P. vexillosa</it>. The higher degree of phosphorylation during the process of attaining competence to settle and metamorphose may be due to fast morphological transitions regulated by various mechanisms. Our data are consistent with previous studies showing a high percentage of phosphorylation during competency in the barnacle <it>Balanus amphitrite </it>and the bryozoan <it>Bugula neritina</it>. The identified phosphoproteins may play an important role during metamorphosis, and further studies on the location and functions of important proteins during metamorphosis are warranted.</p

Dysfunctional allele of the mannose binding protein (MBP) gene in rheumatoid arthritis (RA) - a preliminary study

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Differential replication of avian influenza H9N2 viruses in human alveolar epithelial A549 cells

Avian influenza virus H9N2 isolates cause a mild influenza-like illness in humans. However, the pathogenesis of the H9N2 subtypes in human remains to be investigated. Using a human alveolar epithelial cell line A549 as host, we found that A/Quail/Hong Kong/G1/97 (H9N2/G1), which shares 6 viral "internal genes" with the lethal A/Hong Kong/156/97 (H5N1/97) virus, replicates efficiently whereas other H9N2 viruses, A/Duck/Hong Kong/Y280/97 (H9N2/Y280) and A/Chicken/Hong Kong/G9/97 (H9N2/G9), replicate poorly. Interestingly, we found that there is a difference in the translation of viral protein but not in the infectivity or transcription of viral genes of these H9N2 viruses in the infected cells. This difference may possibly be explained by H9N2/G1 being more efficient on viral protein production in specific cell types. These findings suggest that the H9N2/G1 virus like its counterpart H5N1/97 may be better adapted to the human host and replicates efficiently in human alveolar epithelial cells

Extending the Operating Range of Electric Spring using Back-To-Back Converter: Hardware Implementation and Control

This paper presents the first hardware implementation and control of an electric spring based on a back-to-back converter configuration. Because of its ability to provide both active and reactive power compensation, this back-to-back electric spring (ES-B2B) can substantially extend the operating range of the original version of the electric spring (ES-1) and provide enhanced voltage support and suppression functions. The hardware system and control of the ES-B2B have been successfully developed and tested. The experimental results have confirmed the effectiveness of the ES-B2B in supporting and suppressing the mains voltage. Particularly, the voltage suppression ability of the ES-B2B is superior over that of ES-1. The use of ES-B2B in a simulation study of a weak power grid has also been conducted. The ES-B2B has been found to be highly effective in mitigating voltage fluctuation caused by intermittent renewable power generation

Doctor-diagnosed sleep apnoea in Hong Kong adolescents: prevalence and associations with night-eating and dinner time

Li Ka Shing Faculty of Medicine Frontiers SeriesSession -: Big Data and Precision Medicine: e-Poster no. 17Symposia Theme: ‘MOOCs in Postmodern Asia’ (Oct 27, 2014) and ‘Big Data and Precision Medicine’ (Oct 28, 2014)published_or_final_versio

The K526R substitution in viral protein ​PB2 enhances the effects of E627K on influenza virus replication

Host-adaptive strategies, such as the E627K substitution in the ​PB2 protein, are critical for replication of avian influenza A viruses in mammalian hosts. Here we show that mutation ​PB2-K526R is present in some human H7N9 influenza isolates, in nearly 80% of H5N1 human isolates from Indonesia and, in conjunction with E627K, in almost all seasonal H3N2 viruses since 1970. Polymerase complexes containing ​PB2-526R derived from H7N9, H5N1 or H3N2 viruses exhibit increased polymerase activity. ​PB2-526R also enhances viral transcription and replication in cells. In comparison with viruses carrying 627K, H7N9 viruses carrying both 526R and 627K replicate more efficiently in mammalian (but not avian) cells and in mouse lung tissues, and cause greater body weight loss and mortality in infected mice. ​PB2-K526R interacts with nuclear export protein and our results suggest that it contributes to enhance replication for certain influenza virus subtypes, particularly in combination with 627K.published_or_final_versio

Mammalian adaptation markers in avian-origin H7N9 virus, a comprehensive investigation in isolates and clinical specimens from the H7N9 influenza affected area

Oral PresentationsBackground: An avian-origin H7N9 virus emerged in eastern China in February 2013 and has since caused 133 confirmed human infections (Gao R, et al. N Engl J Med. 2013;368:1888-1897). We have compared human isolates and avian viruses isolated from epidemiologically linked poultry markets and confirmed that the human infections were caused by direct transmission from a poultry source (Chen Y, et al. Lancet. 2013;381:1916-1985). In addition to the Q226L substitution in the HA, which may provide virus with some ability to bind to human-type receptors, what other adaptations has this virus gained to make it different from other avian influenza viruses? Materials and Methods: We characterized H7N9 and other related H7 and N9 subtype viruses isolated in April 2013 from local poultry markets that were associated with human infections. Genetic mutations, polymerases activity, growth kinetic in mammalian and avian cells and replication ability in mice were determined using reverse genetic versions of H7N9 virus. Results: Replication ability and growth kinetics of the avian H7 subtype influenza viruses were compared in avian and mammalian cell lines. Our data suggest that the reassortant H7N9 virus has adapted to, and may have become established in, land-based poultry. It is currently not clear if this virus may still be circulating in some poultry populations, continuing to evolve and posing a threat for further human infections. We studied the virus genome for mammalian adaptation markers by performing sequence analysis on virus isolates and RT-PCR products derived from samples obtained from 46 patients hospitalized in the First Affiliated Hospital of Zhejiang University Medical School, Hangzhou, China. Virus adaptation markers in the HA, NA and PB2 genes were analyzed in sequential samples. Multiple adaptation markers were identified in these genes of clinical isolates and serial respiratory samples. Our data showed that the avian-origin H7N9 has attempted to adapt to replicate in human cells using various mechanisms already displayed by other viruses. An in vitro assay showed that viruses with substitutions at these positions exhibit enhanced RNP polymerase activity, and a study of growth kinetics demonstrated that isolates carrying these adaptation markers replicate to a higher titer in mammalian cells. Replication efficiency of these clinical variants was also evaluated in mice. As neuraminidase inhibitors are used as the first line of antiviral drugs for the treatment of H7N9 infection, we also analyzed oseltamivir resistance-associated mutations in the NA genes of viruses shed in either serial nasal swab or sputum specimens obtained from 40 of the hospitalized patients. Conclusions: This study provides a comprehensive analysis of avian-origin H7N9 virus from poultry and in human infections. The novel H7N9 virus attempted multiple adaptive strategies for efficient replication in humans. Further characterization of this H7N9 avian influenza virus for understanding the mechanism of replication adaptation and the role in efficient human transmission is necessary.published_or_final_versio