680 research outputs found

    Systematic shell-model study on spectroscopic properties in the south region of 208^{208}Pb

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    We aim to study the properties of nuclei in the south region of 208^{208}Pb systematically, including the binding and excitation energies and electromagnetic properties, in order to predict unknown properties of these nuclei, such as isomerism, utilizing a theoretical model which describes the experimentally known properties precisely. We also address whether the N=126N=126 shell closure is robust or not when the proton number decreases from 208^{208}Pb. We performed large-scale shell-model calculations with a new Hamiltonian suggested in the present work. The model space is taken as the five proton orbits within 50<Z8250<Z\leqslant82 and the thirteen neutron orbits within 82<N18482<N\leqslant184. And one-particle one-hole excitation is allowed across the N=126N=126 gap. The Hamiltonian is constructed by combining the existing Hamiltonians, KHHE (with adjustment of its proton-proton part) and KHPE, and the monopole based universal interaction. The shell-model results well reproduce the experimentally observed binding energies and spectroscopic properties, such as isomerism, core excitation, and electromagnetic properties. Some possible isomeric states in neutron-rich Pb, Tl, and Hg isotopes are predicted with transition energies and half-lives. We also examine the effective charges and the quenching of the gg factors suitable for this region by systematic comparisons between observed and calculated electromagnetic properties. A new Hamiltonian is constructed for nuclei in the south region of 208^{208}Pb, mainly including Pb, Tl, Hg, Au, Pt, Ir, Os, Re, and W isotopes around N=126N=126, and provides them reasonable descriptions on nuclear properties including binding energies, excitation energies and electromagnetic properties through comprehensive and systematic studies

    Anticancer Gene Transfer for Cancer Gene Therapy

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    Gene therapy vectors are among the treatments currently used to treat malignant tumors. Gene therapy vectors use a specific therapeutic transgene that causes death in cancer cells. In early attempts at gene therapy, therapeutic transgenes were driven by non-specific vectors which induced toxicity to normal cells in addition to the cancer cells. Recently, novel cancer specific viral vectors have been developed that target cancer cells leaving normal cells unharmed. Here we review such cancer specific gene therapy systems currently used in the treatment of cancer and discuss the major challenges and future directions in this field

    Genome structure of cotton revealed by a genome-wide SSR genetic map constructed from a BC1 population between gossypium hirsutum and G. barbadense

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    <p>Abstract</p> <p>Background</p> <p>Cotton, with a large genome, is an important crop throughout the world. A high-density genetic linkage map is the prerequisite for cotton genetics and breeding. A genetic map based on simple polymerase chain reaction markers will be efficient for marker-assisted breeding in cotton, and markers from transcribed sequences have more chance to target genes related to traits. To construct a genome-wide, functional marker-based genetic linkage map in cotton, we isolated and mapped expressed sequence tag-simple sequence repeats (EST-SSRs) from cotton ESTs derived from the A<sub>1</sub>, D<sub>5</sub>, (AD)<sub>1</sub>, and (AD)<sub>2 </sub>genome.</p> <p>Results</p> <p>A total of 3177 new EST-SSRs developed in our laboratory and other newly released SSRs were used to enrich our interspecific BC<sub>1 </sub>genetic linkage map. A total of 547 loci and 911 loci were obtained from our EST-SSRs and the newly released SSRs, respectively. The 1458 loci together with our previously published data were used to construct an updated genetic linkage map. The final map included 2316 loci on the 26 cotton chromosomes, 4418.9 cM in total length and 1.91 cM in average distance between adjacent markers. To our knowledge, this map is one of the three most dense linkage maps in cotton. Twenty-one segregation distortion regions (SDRs) were found in this map; three segregation distorted chromosomes, Chr02, Chr16, and Chr18, were identified with 99.9% of distorted markers segregating toward the heterozygous allele. Functional analysis of SSR sequences showed that 1633 loci of this map (70.6%) were transcribed loci and 1332 loci (57.5%) were translated loci.</p> <p>Conclusions</p> <p>This map lays groundwork for further genetic analyses of important quantitative traits, marker-assisted selection, and genome organization architecture in cotton as well as for comparative genomics between cotton and other species. The segregation distorted chromosomes can be a guide to identify segregation distortion loci in cotton. The annotation of SSR sequences identified frequent and rare gene ontology items on each chromosome, which is helpful to discover functions of cotton chromosomes.</p

    Optimizing expression and purification of an ATP-binding gene gsiA from Escherichia coli k-12 by using GFP fusion

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    The cloning, expression and purification of the glutathione (sulfur) import system ATP-binding protein (gsiA) was carried out. The coding sequence of Escherichia coli gsiA, which encodes the ATP-binding protein of a glutathione importer, was amplified by PCR, and then inserted into a prokaryotic expression vector pWaldo-GFPe harboring green fluorescent protein (GFP) reporter gene. The resulting recombinant plasmid pWaldo-GFP-GsiA was transformed into various E. coli strains, and expression conditions were optimized. The effect of five E. coli expression strains on the production of the recombinant gsiA protein was evaluated. E. coli BL21 (DE3) was found to be the most productive strain for GsiA-GFP fusion-protein expression, most of which was insoluble fraction. However, results from in-gel and Western blot analysis suggested that expression of recombinant GsiA in Rosetta (DE3) provides an efficient source in soluble form. By using GFP as reporter, the most suitable host strain was conveniently obtained, whereby optimizing conditions for overexpression and purification of the proteins for further functional and structural studies, became, not only less laborious, but also time-saving

    Intestinal Absorption and First-Pass Metabolism of Polyphenol Compounds in Rat and Their Transport Dynamics in Caco-2 Cells

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    <div><h3>Background</h3><p>Polyphenols, a group of complex naturally occurring compounds, are widely distributed throughout the plant kingdom and are therefore readily consumed by humans. The relationship between their chemical structure and intestinal absorption, transport, and first-pass metabolism remains unresolved, however.</p> <h3>Methods</h3><p>Here, we investigated the intestinal absorption and first-pass metabolism of four polyphenol compounds, apigenin, resveratrol, emodin and chrysophanol, using the <em>in vitro</em> Caco-2 cell monolayer model system and <em>in situ</em> intestinal perfusion and <em>in vivo</em> pharmacokinetic studies in rats, so as to better understand the relationship between the chemical structure and biological fate of the dietary polyphenols.</p> <h3>Conclusion</h3><p>After oral administration, emodin and chrysophanol exhibited different absorptive and metabolic behaviours compared to apigenin and resveratrol. The differences in their chemical structures presumably resulted in differing affinities for drug-metabolizing enzymes, such as glucuronidase and sulphatase, and transporters, such as MRP2, SGLT1, and P-glycoprotein, which are found in intestinal epithelial cells.</p> </div

    Tumor-suppressor activity of RRIG1 in breast cancer

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    <p>Abstract</p> <p>Background</p> <p>Retinoid receptor-induced gene-1 (RRIG1) is a novel gene that has been lost in several types of human cancers. The aim of this study was to determine whether RRIG1 plays a role in breast cancer, such as in the suppression of breast cancer cell growth and invasion.</p> <p>Methods</p> <p>Immunohistochemistry was used to detect RRIG1 expression in breast tissue specimens. Gene transfection was used to restore or knock down RRIG1 expression in breast cancer cell lines for analysis of cell viability, colony formation, and migration/invasion potential. Reverse-transcription polymerase chain reaction and western blot assays were used to detect the changes in gene expression. The RhoA activation assay was used to assess RRIG1-induced inhibition of RhoA activity.</p> <p>Results</p> <p>The immunohistochemical data showed that <it>RRIG1 </it>expression was reduced in breast cancer tissues compared with normal and atypical hyperplastic breast tissues. <it>RRIG1 </it>expression was inversely correlated with lymph node metastasis of breast cancer but was not associated with the status of hormone receptors, such as estrogen receptor, progesterone receptor, or HER2. Furthermore, restoration of <it>RRIG1 </it>expression inhibited proliferation, colony formation, migration, and invasion of breast cancer cells. Expression of RRIG1 also reduced phosphorylated Erk1/2 and Akt levels; c-Jun, MMP9, and Akt expressions; and RhoA activity. In contrast, knockdown of RRIG1 expression promoted breast cancer cell proliferation, colony formation, migration, and invasion potential.</p> <p>Conclusion</p> <p>The data from the current study indicated that <it>RRIG1 </it>expression was reduced or lost in breast cancer and that restoration of RRIG1 expression suppressed breast cancer cell growth and invasion capacity. Future studies will determine the underlying molecular mechanisms and define RRIG1 as a tumor-suppressor gene in breast cancer.</p

    Asian dust storm observed at a rural mountain site in southern China : chemical evolution and heterogeneous photochemistry

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    Author name used in this publication: Nie, W.Author name used in this publication: Wang, T.Author name used in this publication: Xue, L. K.Author name used in this publication: Wang, X. F.Author name used in this publication: Gao, X. M.Author name used in this publication: Zhang, Q. Z.Author name used in this publication: Wang, W. X.2012-2013 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    The two sides of cytokine signaling and glaucomatous optic neuropathy

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    The mechanistic study of glaucoma pathogenesis has shifted to seeking to understand the effects of immune responses on retinal ganglion cell damage and protection. Cytokines are the hormonal factors that mediate most of the biological effects in both the immune and nonimmune systems. CD4-expressing T helper cells are a major source of cytokine production and regulation. Type 1 helper T (Th1) cells are characterized by the production of proinflammatory cytokines such as interferon-gamma, interleukin (IL)-2, IL-12, IL-23, and tumor necrosis factor-alpha while type 2 helper T (Th2) cells are characterized by the production of IL-4, IL-5, IL-6, and IL-10. The balance of Th1/Th2 cytokine production influences many pathological processes and plays both causative and protective roles in neuron damages. Growing evidence indicates that imbalances of Th1/Th2 cytokine production are involved in neural damage or protection in many neurological diseases. In this review, we discuss the possible roles of Th1/Th2 cytokine production and imbalance of Th1/Th2 cytokines in retina, especially glaucomatous optic neuropathy
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