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Find video protocols related to scientific articles indexed in Pubmed.
Dually Actuated Triple Shape Memory Polymers of Cross-Linked Polycyclooctene-Carbon Nanotube/Polyethylene Nanocomposites.
ACS Appl Mater Interfaces
PUBLISHED: 10-28-2014
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In this work, electrically and thermally actuated triple shape memory polymers (SMPs) of chemically cross-linked polycyclooctene (PCO)-multiwalled carbon nanotube (MWCNT)/polyethylene (PE) nanocomposites with co-continuous structure and selective distribution of fillers in PCO phase are prepared. We systematically studied not only the microstructure including morphology and fillers' selective distribution in one phase of the PCO/PE blends, but also the macroscopic properties including thermal, mechanical, and electrical properties. The co-continuous window of the immiscible PCO/PE blends is found to be the volume fraction of PCO (v(PCO)) of ca. 40-70 vol %. The selective distribution of fillers in one phase of co-continuous blends is obtained by a masterbatch technique. The prepared triple SMP materials show pronounced triple shape memory effects (SMEs) on the dynamic mechanical thermal analysis (DMTA) and the visual observation by both thermal and electric actuations. Such polyolefin samples with well-defined microstructure, electrical actuation, and triple SMEs might have potential applications as, for example, multiple autochoke elements for engines, self-adjusting orthodontic wires, and ophthalmic devices.
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The Effects of Macrophage-Stimulating Protein on the Migration, Proliferation and Collagen Synthesis of Skin Fibroblasts in Vitro and in Vivo.
Tissue Eng Part A
PUBLISHED: 10-16-2014
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Macrophage-stimulating protein (MSP), an important cytokine with multiple functions, is highly expressed in adipose mesenchymal stem cells-conditioned medium (ASC-CM). ASCs can effectively promote wound healing through paracrine mechanism, suggesting that MSP may play a critical role in wound healing. Through binding to its receptor, RON, it can activate epithelial cells and work as an inflammatory mediator. In this study, we found RON was also expressed on dermal fibroblasts and investigated the effects of MSP on proliferation, migration and collagen synthesis of fibroblasts. With the treatment of different concentrations of MSP (0, 1, 10, 20, 50, and 100ng/ml) on fibroblasts, proliferation, migration and collagen synthesis were analyzed by CCK-8, transwell and RT-PCR. Under the treatment of MSP, the migration, Collagen I ,?synthesis and MMP1 mRNA expression of fibroblasts were up-regulated significantly, although there was no effect on fibroblasts proliferation, and the optimal concentration of MSP for migration and collagen synthesis was 10ng/ml. In the in vivo study, 10ng/ml MSP was applied to full-thickness skin wound with bacterial cellulose membranes, and this treatment could accelerate the wound healing rate and increased the collagen synthesis of wound sites. This study suggested that MSP appears to promote the migration of fibroblasts, enhances collagen synthesis and remodeling, and to effectively improve wound healing.
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Estimating Position of Mobile Robots From Omnidirectional Vision Using an Adaptive Algorithm.
IEEE Trans Cybern
PUBLISHED: 09-30-2014
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This paper presents a novel and simple adaptive algorithm for estimating the position of a mobile robot with high accuracy in an unknown and unstructured environment by fusing images of an omnidirectional vision system with measurements of odometry and inertial sensors. Based on a new derivation where the omnidirectional projection can be linearly parameterized by the positions of the robot and natural feature points, we propose a novel adaptive algorithm, which is similar to the Slotine-Li algorithm in model-based adaptive control, to estimate the robot's position by using the tracked feature points in image sequence, the robot's velocity, and orientation angles measured by odometry and inertial sensors. It is proved that the adaptive algorithm leads to global exponential convergence of the position estimation errors to zero. Simulations and real-world experiments are performed to demonstrate the performance of the proposed algorithm.
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Facile preparation of an n-type reduced graphene oxide field effect transistor at room temperature.
Chem. Commun. (Camb.)
PUBLISHED: 09-27-2014
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We introduce a facile method to prepare an n-type reduced graphene oxide field effect transistor at room temperature via a typical Benkeser reduction using lithium and ethylenediamine.
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PDGF receptor-? promotes TGF-? signaling in hepatic stellate cells via transcriptional and posttranscriptional regulation of TGF-? receptors.
Am. J. Physiol. Gastrointest. Liver Physiol.
PUBLISHED: 08-28-2014
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Platelet-derived growth factor (PDGF) and transforming growth factor-? (TGF-?) signaling are required for hepatic stellate cell (HSC) activation under pathological conditions such as liver metastatic tumor growth. These two signaling pathways are functionally divergent; PDGF signaling promotes proliferation and migration of HSCs, and TGF-? induces transdifferentiation of quiescent HSCs into myofibroblasts. Although PDGF signaling is implicated in TGF-?-mediated epithelial mesenchymal transition of tumor cells, the role of PDGF receptors in TGF-? activation of HSCs has not been investigated. Here we report that PDGF receptor-? (PDGFR-?) is required for TGF-? signaling of cultured human HSCs although HSCs express both PDGF-? and -? receptors. PDGFR-? knockdown inhibits TGF-?-induced phosphorylation and nuclear accumulation of SMAD2 with no influence on AKT or ERK phosphorylation associated with noncanonical TGF-? signaling. PDGFR-? knockdown suppresses TGF-? receptor I (T?RI) but increases T?RII gene transcription. At the protein level, PDGFR-? is recruited to T?RI/T?RII complexes by TGF-? stimulation. PDGFR-? knockdown blocks TGF-?-mediated internalization of T?RII and induces accumulation of T?RII at the plasma membrane, thereby inhibiting TGF-? phosphorylation of SMAD2. Functionally, knockdown of PDGFR-? reduces paracrine effects of HSCs on colorectal cancer cell proliferation and migration in vitro. In mice and patients, colorectal cancer cell invasion of the liver induces upregulation of PDGFR-? of HSCs. In summary, our finding that PDGFR-? knockdown inhibits SMAD-dependent TGF-? signaling by repressing T?RI transcriptionally and blocking endocytosis of TGF-? receptors highlights a convergence of PDGF and TGF-? signaling for HSC activation and PDGFR-? as a therapeutic target for liver metastasis and other settings of HSC activation.
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Monolayer MoS2 Films Supported by 3D Nanoporous Metals for High-Efficiency Electrocatalytic Hydrogen Production.
Adv. Mater. Weinheim
PUBLISHED: 08-20-2014
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The "edge-free" monolayer MoS2 films supported by 3D nanoporous gold show high catalytic activities towards HER, originating from large out-of-plane strains that are geometrically required to manage the 3D curvature of bicontinuous nanoporosity. The large lattice bending leads to local semiconductor-to-metal transition of 2H MoS2 and the formation of catalytically active sites for HER.
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Dynamism of the mitral annulus: a spatial and temporal analysis.
J. Cardiothorac. Vasc. Anesth.
PUBLISHED: 08-15-2014
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In this study, the authors sought to investigate the extent and timing of changes in mitral annular area during the cardiac cycle. Particularly, the authors assessed whether these changes were limited to the posterior part of the annulus or were more global in nature.
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PAAT, a novel ATPase and trans-regulator of mitochondrial ABC transporters, is critically involved in the maintenance of mitochondrial homeostasis.
FASEB J.
PUBLISHED: 07-25-2014
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ATP-binding cassette (ABC) transporters are implicated in a diverse range of physiological and pathophysiological processes, such as cholesterol and lipid transportation and multidrug resistance. Despite the considerable efforts made in understanding of the cellular function of ABC proteins, the regulation mechanism of this type of protein is still poorly defined. Here we report the identification and functional characterization of a novel ATPase protein, protein associated with ABC transporters (PAAT), in humans. PAAT contains a nucleotide-binding domain (NBD)-like domain and a signal for intramitochondrial sorting. We showed that PAAT is localized in both the cytoplasm and the mitochondria and has an intrinsic ATPase activity. PAAT physically interacts with the 3 known mitochondrial inner membrane ABC proteins, ABCB7, ABCB8, and ABCB10, but not ABCB1, ABCB6, or ABCG2, and functionally regulates the transport of ferric nutrients and heme biosynthesis. Significantly, PAAT deficiency promotes cell death, reduces mitochondrial potential, and sensitizes mitochondria to oxidative stress-induced DNA damages. Our experiments revealed that PAAT is a novel ATPase and a trans-regulator of mitochondrial ABC transporters that plays an important role in the maintenance of mitochondrial homeostasis and cell survival.-Yang, X., Yang, J., Li, L., Sun, L., Yi, X., Han, X., Si, W., Yan, R., Chen, Z., Xie, G., Li, W., Shang, Y., Liang, J. PAAT, a novel ATPase and trans-regulator of mitochondrial ABC transporters, is critically involved in the maintenance of mitochondrial homeostasis.
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Studies on Quantitative Determination of Total Alkaloids and Berberine in Five Origins of Crude Medicine "Sankezhen"
J Chromatogr Sci
PUBLISHED: 07-12-2014
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The roots of Berberis plants are widely used as a traditional Chinese medicine called "Sankezhen", having the activities of antibacterial and anti-inflammatory, and the ingredients are alkaloids. This work aims to study and compare the total alkaloids and individual alkaloid (berberine) contents in roots and stems from five origins of Berberis plants (Berberis soulieana Schneid., B. henryana Schneid., B. triacanthophora Fedde, B. gagnepainii Schneid. and B. bergmanniae Schneid.) and provides some references for resource and quality evaluation of the medicine. Acid dye colorimetry and high-performance liquid chromatography were used in the determination. The results showed that the contents for the total alkaloids in root and stem samples were in the range of 1.60-4.72% and 0.76-2.70%, while those of the berberine were 0.70-2.92% and 0.23-1.07%. With higher contents of the total alkaloids and berberine, the roots of B. soulieana, B. gagnepainii and B. bergmanniae were good sources of "Sankezhen". Meanwhile, the contents were also high in stems of the three plants, indicating that the stems were likely to be alternative sources of "Sankezhen" after further research. As the results of precision, stability and recovery tests shown, the methods were simple, rapid and reliable, and provided valuable basis for quality evaluation and new resource investigation of "Sankezhen".
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Substantial performance improvement in inverted polymer light-emitting diodes via surface plasmon resonance induced electrode quenching control.
ACS Appl Mater Interfaces
PUBLISHED: 07-10-2014
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Inverted-type polymer light-emitting diodes with Au nanoparticles modified ITO cathode has exhibited improved brightness from 5900 to 15,000 cd m(-2) (1.5-fold enhancement) and enhanced luminous efficiency from 4.4 to 10.5 cd A(-1) (1.4-fold enhancement), when greenish emissive polymer-P-PPV was applied as active layer. Both the experimental and theoretical results show that it is mainly attributed to effective overlapping between local surface plasmon resonance induced by Au nanopartices and excitons quenching region at ZnO/P-PPV interface, which makes originally electrode-quenched excitons emissive and increases excitons efficiency.
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The First Five-Membered-Heterocycle-Fused Subphthalocyanine Analogues: Chiral?Tri(benzo[b]thiopheno)subporphyrazines.
Chemistry
PUBLISHED: 06-29-2014
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Two tri(benzo[b]thiopheno)subporphyrazine regioisomers with C3 and C1 molecular symmetry have been isolated from the cyclotrimerization of benzo[b]thiophene-2,3-dicarbonitrile as the first five-membered-heterocycle-fused subphthalocyanine analogues. Optical resolution of both regioisomers was achieved by using a chiral HPLC technique, affording the first chiral subphthalocyanine analogues.
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Whole-exome sequencing of endometriosis identifies frequent alterations in genes involved in cell adhesion and chromatin-remodeling complexes.
Hum. Mol. Genet.
PUBLISHED: 06-26-2014
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Endometriosis is a complex and enigmatic disease that arises from the interplay among multiple genetic and environmental factors. The defining feature of endometriosis is the deposition and growth of endometrial tissues at sites outside of the uterine cavity. Studies to date have established that endometriosis is heritable but have not addressed the causal genetic variants for this disease. Here, we conducted whole-exome sequencing to comprehensively search for somatic mutations in both eutopic and ectopic endometrium from 16 endometriosis patients and five normal control patients using laser capture microdissection. We compared the mutational landscape of ectopic endometrium with the corresponding eutopic sample from endometriosis patients compared with endometrium from normal women and identified previously unreported mutated genes and pathway alternations. Statistical analysis of exome data identified that most genes were specifically mutated in both eutopic and ectopic endometrium cells. In particular, genes that are involved in biological adhesion, cell-cell junctions, and chromatin-remodeling complex(es) were identified, which partially supports the retrograde menstruation theory that proposes that endometrial cells are refluxed through the fallopian tubes during menstruation and implanted onto the peritoneum or pelvic organs. Conspicuously, when we compared exomic mutation data for paired eutopic and ectopic endometrium, we identified a mutational signature in both endometrial types for which no overlap in somatic single nucleotide variants were observed. These mutations occurred in a mutually exclusive manner, likely because of the discrepancy in endometriosis pathology and physiology, as eutopic endometrium rapidly regrows, and ectopic endometrial growth is inert. Our findings provide, to our knowledge, an unbiased view of the landscape of genetic alterations in endometriosis and vital information for indicating that genetic alterations in cytoskeletal and chromatin-remodeling proteins could be involved in the pathogenesis of endometriosis, thus implicating a novel therapeutic possibility for endometriosis.
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Synthesis and spectroscopic properties of chiral binaphthyl-linked subphthalocyanines.
Chem. Commun. (Camb.)
PUBLISHED: 06-06-2014
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Chiral binaphthyl-linked subphthalocyanines (SubPcs) (1) have been prepared by the cyclotrimerization reaction of a phthalonitrile linked with (R)- and (S)-2,2'-binaphthyl in the presence of BCl3, and characterized by various spectroscopies including NMR, electronic absorption, CD, and MCD, as well as electrochemistry.
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Imaging of buried 3D magnetic rolled-up nanomembranes.
Nano Lett.
PUBLISHED: 06-06-2014
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Increasing performance and enabling novel functionalities of microelectronic devices, such as three-dimensional (3D) on-chip architectures in optics, electronics, and magnetics, calls for new approaches in both fabrication and characterization. Up to now, 3D magnetic architectures had mainly been studied by integral means without providing insight into local magnetic microstructures that determine the device performance. We prove a concept that allows for imaging magnetic domain patterns in buried 3D objects, for example, magnetic tubular architectures with multiple windings. The approach is based on utilizing the shadow contrast in transmission X-ray magnetic circular dichroism (XMCD) photoemission electron microscopy and correlating the observed 2D projection of the 3D magnetic domains with simulated XMCD patterns. That way, we are not only able to assess magnetic states but also monitor the field-driven evolution of the magnetic domain patterns in individual windings of buried magnetic rolled-up nanomembranes.
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A Single Rolled-Up Si Tube Battery for the Study of Electrochemical Kinetics, Electrical Conductivity, and Structural Integrity.
Adv. Mater. Weinheim
PUBLISHED: 06-04-2014
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A lab-on-chip device is demonstrated for probing the electrochemical kinetics, electrical properties, and structure integrity of a single Si rolled-up tube as the anode in lithium-ion batteries (LIBs). Cyclic voltammetry of the tube exhibits better-resolved peaks than of the planar film due to the enhanced diffusion. The tube is wrinkled after cycling. The tube could be used as a promising ultra-microelectrode for other voltammetry research.
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A correlation study of the expression of resistin and glycometabolism in muscle tissue after traumatic brain injury in rats.
Chin. J. Traumatol.
PUBLISHED: 06-04-2014
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To investigate the expression pattern of resistin (RSTN) in skeletal muscle tissue and its influence on glycometabolism in rats with traumatic brain injury (TBI).
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Low-temperature solution-processable Ni(OH)2 ultrathin nanosheet/N-graphene nanohybrids for high-performance supercapacitor electrodes.
Nanoscale
PUBLISHED: 04-28-2014
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A novel and facile strategy is developed to fabricate highly nitrogen-doped graphene (N-graphene) based layered, quasi-two-dimensional nanohybrids with ultrathin nanosheet nanocrystals using a low-temperature, solution processing method for high-performance supercapacitor electrodes. High N doping can be achieved together with one of the lowest oxygen content in chemically reduced graphene and related nanohybrids at low temperature by large-scale residue defects of chemically reduced graphene. The layered, quasi-two-dimensional nanohybrids or heterostructures of ultrathin Ni(OH)2 nanosheet nanocrystal/N-graphene can be applied in supercapacitor electrodes with ultrahigh capacitances of ?1551 F g(-1), excellent rate performance in the scan measurements (from 2 mV s(-1) to 100 mV s(-1)) and in the discharge tests (from 1.5 A g(-1) to 30 A g(-1)) and good cycling stability. Moreover, the capacitance of Ni(OH)2 nanosheet/N-graphene nanohybrids is two and one orders of magnitude higher than that for pure nanocrystals and for the physical mixture of nanocrystal/N-graphene, respectively. Electron transfer in supercapacitor electrodes based on nanohybrids is over 100 times faster than that in electrodes from pure nanocrystals and several tens of times faster than that in electrodes from nanocrystal/N-graphene mixtures. This low-temperature method may provide a low-cost, solution-processable and easily scalable route to high-performance graphene nanohybrid electrodes for energy applications.
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Tricuspid Annulus: A Three-Dimensional Deconstruction and Reconstruction.
Ann. Thorac. Surg.
PUBLISHED: 04-19-2014
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Before clinical manifestation of regurgitation, the tricuspid annulus dilates and flattens when right ventricular dysfunction is potentially reversible. That makes the case for a prophylactic tricuspid annuloplasty even in the absence of significant tricuspid regurgitation. Owing to the appreciation of the favorable prognostic value of tricuspid annuloplasty, the geometry of the normal tricuspid annulus merits critical analysis.
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The cytochrome P450 genes of channel catfish: their involvement in disease defense responses as revealed by meta-analysis of RNA-Seq data sets.
Biochim. Biophys. Acta
PUBLISHED: 04-18-2014
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Cytochrome P450s (CYPs) encode one of the most diverse enzyme superfamily in nature. They catalyze oxidative reactions of endogenous molecules and exogenous chemicals.
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Poloxamer-188 Can Attenuate Blood-Brain Barrier Damage to Exert Neuroprotective Effect in Mice Intracerebral Hemorrhage Model.
J. Mol. Neurosci.
PUBLISHED: 03-27-2014
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Blood-brain barrier (BBB) disruption and brain edema formation play important roles in the secondary neuronal death and neurological dysfunction induced by intracerebral hemorrhage (ICH). Poloxamer 188 (P188), a multiblock copolymer surfactant, has been shown to be capable of sealing damaged cell membranes and decrease neuronal cell death. In this study, we explored whether P188 had a protective effect against ICH and its underlying mechanisms. Male ICR mice were subjected to infusion of type IV collagenase (to induce ICH) of saline (for shams) into the left striatum. The results showed that P188-12 mg post-treatment by tail intravenous injection significantly ameliorated the neurological symptoms and brain edema, attenuated BBB permeability, and decreased cell insults and injury volume at 24 and 72 h after ICH. Furthermore, P188 maintained the protein levels of tight junction (TJ) proteins including claudin-5, occludin, and zonula occludens-1, and reversed the increases of nuclear factor-kappaB (NF-?B), matrix metalloproteinase (MMP)-2, and MMP-9 protein expression at 72 h post ICH. Immunofluorescence showed P188 treatment rearranged the structure of TJ proteins in a continuous and linear pattern. Therefore, the present study concludes that P188 can protect against ICH, and the protective effect was associated with preventing BBB disruption through NF-?B-MMPs-mediated TJ proteins degradation.
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Destabilizing LSD1 by Jade-2 promotes neurogenesis: an antibraking system in neural development.
Mol. Cell
PUBLISHED: 03-24-2014
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Histone H3K4 demethylase LSD1 plays an important role in stem cell biology, especially in the maintenance of the silencing of differentiation genes. However, how the function of LSD1 is regulated and the differentiation genes are derepressed are not understood. Here, we report that elimination of LSD1 promotes embryonic stem cell (ESC) differentiation toward neural lineage. We showed that the destabilization of LSD1 occurs posttranscriptionally via the ubiquitin-proteasome pathway by an E3 ubiquitin ligase, Jade-2. We demonstrated that Jade-2 is a major LSD1 negative regulator during neurogenesis in vitro and in vivo in both mouse developing cerebral cortices and zebra fish embryos. Apparently, Jade-2-mediated degradation of LSD1 acts as an antibraking system and serves as a quick adaptive mechanism for re-establishing epigenetic landscape without more laborious transcriptional regulations. As a potential anticancer strategy, Jade-2-mediated LSD1 degradation could potentially be used in neuroblastoma cells to induce differentiation toward postmitotic neurons.
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Pathogen recognition receptors in channel catfish: IV. Identification, phylogeny and expression analysis of peptidoglycan recognition proteins.
Dev. Comp. Immunol.
PUBLISHED: 03-15-2014
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Peptidoglycan recognition proteins (PGRPs) can recognize bacterial cell wall (peptidoglycan) and activate innate immune system. In addition to its function as pathogen recognition receptors (PRRs), PGRPs are also involved in directly killing bacteria, and regulating multiple signaling pathways. Recently, we have reported catfish PRRs including nucleotide-binding domain, leucine-rich repeat containing receptors (NLRs), retinoic acid inducible gene I (RIG-I) like receptors (RLRs), and Toll-like receptors (TLRs). In this study, we identified and characterized the PGRP gene family in channel catfish which included two members, PGLYRP-5 and PGLYRP-6. Phylogenetic analysis, syntenic analysis and protein structural analysis were conducted to determine their identities and evolutionary relationships. In order to gain insight into the roles of PGRPs in catfish innate immune responses, quantitative real-time PCR was used to investigate the expression profiles in catfish healthy tissues and after bacterial infection. Both PGLYRP-5 and PGLYRP-6 were ubiquitously expressed in all 12 healthy tissues, and most highly expressed in gill and spleen, respectively. Distinct expression patterns were observed for PGRPs after infection with Edwardsiella ictaluri and Flavobacterium columnare, both Gram-negative bacteria. After infection with E. ictaluri, both PGLYRP-5 and PGLYRP-6 were significantly down-regulated at a certain time-point, while both genes were generally up-regulated in the gill after infection with F. columnare. Collectively, these findings suggested that PGRPs may play complex roles in the host immune response to bacterial pathogens in catfish.
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JMJD6 promotes colon carcinogenesis through negative regulation of p53 by hydroxylation.
PLoS Biol.
PUBLISHED: 03-01-2014
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Jumonji domain-containing 6 (JMJD6) is a member of the Jumonji C domain-containing family of proteins. Compared to other members of the family, the cellular activity of JMJD6 is still not clearly defined and its biological function is still largely unexplored. Here we report that JMJD6 is physically associated with the tumor suppressor p53. We demonstrated that JMJD6 acts as an ?-ketoglutarate- and Fe(II)-dependent lysyl hydroxylase to catalyze p53 hydroxylation. We found that p53 indeed exists as a hydroxylated protein in vivo and that the hydroxylation occurs mainly on lysine 382 of p53. We showed that JMJD6 antagonizes p53 acetylation, promotes the association of p53 with its negative regulator MDMX, and represses transcriptional activity of p53. Depletion of JMJD6 enhances p53 transcriptional activity, arrests cells in the G1 phase, promotes cell apoptosis, and sensitizes cells to DNA damaging agent-induced cell death. Importantly, knockdown of JMJD6 represses p53-dependent colon cell proliferation and tumorigenesis in vivo, and significantly, the expression of JMJD6 is markedly up-regulated in various types of human cancer especially in colon cancer, and high nuclear JMJD6 protein is strongly correlated with aggressive clinical behaviors of colon adenocarcinomas. Our results reveal a novel posttranslational modification for p53 and support the pursuit of JMJD6 as a potential biomarker for colon cancer aggressiveness and a potential target for colon cancer intervention.
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Development of the catfish 250K SNP array for genome-wide association studies.
BMC Res Notes
PUBLISHED: 02-28-2014
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Quantitative traits, such as disease resistance, are most often controlled by a set of genes involving a complex array of regulation. The dissection of genetic basis of quantitative traits requires large numbers of genetic markers with good genome coverage. The application of next-generation sequencing technologies has allowed discovery of over eight million SNPs in catfish, but the challenge remains as to how to efficiently and economically use such SNP resources for genetic analysis.
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In vitro particle image velocity measurements in a model root canal: flow around a polymer rotary finishing file.
J Endod
PUBLISHED: 02-26-2014
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Root canal irrigation is vital to thorough debridement and disinfection, but the mechanisms that contribute to its effectiveness are complex and uncertain. Traditionally, studies in this area have relied on before-and-after static comparisons to assess effectiveness, but new in situ tools are being developed to provide real-time assessments of irrigation. The aim in this work was to measure a cross section of the velocity field in the fluid flow around a polymer rotary finishing file in a model root canal.
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Vasodilator-stimulated phosphoprotein promotes activation of hepatic stellate cells by regulating Rab11-dependent plasma membrane targeting of transforming growth factor beta receptors.
Hepatology
PUBLISHED: 02-25-2014
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Liver microenvironment is a critical determinant for development and progression of liver metastasis. Under transforming growth factor beta (TGF-?) stimulation, hepatic stellate cells (HSCs), which are liver-specific pericytes, transdifferentiate into tumor-associated myofibroblasts that promote tumor implantation (TI) and growth in the liver. However, the regulation of this HSC activation process remains poorly understood. In this study, we tested whether vasodilator-stimulated phosphoprotein (VASP) of HSCs regulated the TGF-?-mediated HSC activation process and tumor growth. In both an experimental liver metastasis mouse model and cancer patients, colorectal cancer cells reaching liver sinusoids induced up-regulation of VASP and alpha-smooth muscle actin (?-SMA) in adjacent HSCs. VASP knockdown in HSCs inhibited TGF-?-mediated myofibroblastic activation of HSCs, TI, and growth in mice. Mechanistically, VASP formed protein complexes with TGF-? receptor II (T?RII) and Rab11, a Ras-like small GTPase and key regulator of recycling endosomes. VASP knockdown impaired Rab11 activity and Rab11-dependent targeting of T?RII to the plasma membrane, thereby desensitizing HSCs to TGF-?1 stimulation. Conclusions: Our study demonstrates a requirement of VASP for TGF-?-mediated HSC activation in the tumor microenvironment by regulating Rab11-dependent recycling of T?RII to the plasma membrane. VASP and its effector, Rab11, in the tumor microenvironment thus present therapeutic targets for reducing TI and metastatic growth in the liver. (Hepatology 2014).
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Nanoporous metal enhanced catalytic activities of amorphous molybdenum sulfide for high-efficiency hydrogen production.
Adv. Mater. Weinheim
PUBLISHED: 02-19-2014
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We fabricated a robust electrocatalyst by chemically depositing an ultrathin layer of amorphous molybdenum sulfide on the internal surface of dealloyed nanoporous gold. The catalyst exhibits superior electrocatalysis toward hydrogen evolution reaction in both acidic and neutral media with 2-6 times improvement in catalytic activies compared to other molybdenum sulfide based materials.
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Direct electrochemistry and electrocatalysis of hemoglobin in graphene oxide and ionic liquid composite film.
Mater Sci Eng C Mater Biol Appl
PUBLISHED: 02-18-2014
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In this paper a novel sensing platform based on graphene oxide (GO), ionic liquid (IL) 1-ethyl-3-methylimidazolium tetrafluoroborate and Nafion for the immobilization of hemoglobin (Hb) was adopted with a carbon ionic liquid electrode (CILE) as the substrate electrode, which was denoted as Nafion/Hb-GO-IL/CILE. Spectroscopic results suggested that Hb molecules were not denatured in the composite. A pair of well-defined redox peaks appeared on the cyclic voltammogram, which was attributed to the realization of direct electron transfer of Hb on the electrode. Electrochemical behaviors of Hb entrapped in the film were carefully investigated by cyclic voltammetry with the electrochemical parameters calculated. Based on the catalytic ability of the immobilized Hb, Nafion/Hb-GO-IL/CILE exhibited excellent electrocatalytic behavior towards the reduction of different substrates such as trichloroacetic acid in the concentration range from 0.01 to 40.0mM with the detection limit as 3.12 ?M (3?), H2O2 in the concentration range from 0.08 to 635.0 ?M with the detection limit as 0.0137 ?M (3?) and NaNO2 in the concentration range from 0.5 to 800.0 ?M with the detection limit as 0.0104 ?M (3?). So the proposed bioelectrode could be served as a new third-generation electrochemical sensor without mediator.
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The synergistic effect of nanoporous AuPd alloy catalysts on highly chemoselective 1,4-hydrosilylation of conjugated cyclic enones.
Chem. Commun. (Camb.)
PUBLISHED: 02-18-2014
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The nanoporous AuPd (AuPdNPore) alloy catalyst showed superior chemoselectivity and high catalytic activity for the direct 1,4-hydrosilylation of the conjugated cyclic enones with hydrosilane in comparison with the monometallic nanoporous Au and Pd catalysts. The enhanced catalytic properties of AuPdNPore arise mainly from the nanoporous structure and the synergistic effect of the AuPd alloy.
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Fluorescent graphene quantum dot nanoprobes for the sensitive and selective detection of mercury ions.
Spectrochim Acta A Mol Biomol Spectrosc
PUBLISHED: 02-17-2014
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Graphene quantum dots were prepared by ultrasonic route and served as a highly selective water-soluble probe for sensing of Hg(2+). The fluorescence emission spectrum of graphene quantum dots was at about 430nm. In the presence of Hg(2+), the fluorescence of the quantum dots significantly quenched. And the fluorescence intensity gradually decreased with the increasing concentration of Hg(2+). The change of fluorescence intensity is directly proportional to the concentration of Hg(2+). Under optimum conditions, the linear range for the detection of Hg(2+) was 8.0×10(-7) to 9×10(-6)M with a detection limit of 1.0×10(-7)M. In addition, the preliminary mechanism of fluorescence quenching was discussed in the paper. The constructed sensor with high sensitivity and selectivity, simple, rapid properties makes it valuable for further application.
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A rapid nested polymerase chain reaction method to detect circulating cancer cells in breast cancer patients using multiple marker genes.
Oncol Lett
PUBLISHED: 02-14-2014
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The aim of the present study was to develop a simple and rapid method for the detection of circulating cancer cells using multiple tumor markers and to investigate the clinical significance of circulating cancer cells in breast cancer patients. A novel rapid nested polymerase chain reaction (PCR) assay, with high sensitivity and specificity, was evaluated, which was considered to be suitable for clinical application. The rapid nested PCR method was used to detect the circulating cancer cells of 142 breast cancer patients, using a panel of marker genes (FAM83A, NPY1R and KRT19), which were identified by the Digital Gene Expression Displayer Tool of the National Cancer Institute-Cancer Genome Anatomy Project. In total, 79.6% of the 142 breast cancer patient blood samples were found to express at least one tumor marker. In addition, the number of positive markers was found to significantly correlate with the disease stage and presence of distant metastasis. Furthermore, positivity for more than one tumor marker appeared to predict a reduced survival time in breast cancer patients.
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Atomic observation of catalysis-induced nanopore coarsening of nanoporous gold.
Nano Lett.
PUBLISHED: 02-13-2014
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Dealloyed nanoporous metals have attracted much attention because of their excellent catalytic activities toward various chemical reactions. Nevertheless, coarsening mechanisms in these catalysts have not been experimentally studied. Here, we report in situ atomic-scale observations of the structural evolution of nanoporous gold during catalytic CO oxidation. The catalysis-induced nanopore coarsening is associated with the rapid diffusion of gold atoms at chemically active surface steps and the surface segregation of residual Ag atoms, both of which are stimulated by the chemical reaction. Our observations provide the first direct evidence that planar defects hinder nanopore coarsening, suggesting a new strategy for developing structurally stable and highly active heterogeneous catalysts.
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Resolvin E1 reduces hepatic fibrosis in mice with Schistosoma japonicum infection.
Exp Ther Med
PUBLISHED: 02-10-2014
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The aim of this study was to investigate whether resolvin E1 (RvE1) protects against hepatic fibrosis in a murine model of liver fibrosis induced by Schistosoma japonicum infection. A total of 30 pathogen-free Kunming mice were randomly and equally divided into three groups: Control (uninfected, untreated), model (infected, untreated) and RvE1 intervention (infected, RvE1-treated; 100 ng daily). The mice were infected with Schistosoma japonicum by inoculating the abdominal skin with 20±2 cercariae to induce models of liver fibrosis. The area and numbers of the granulomas in the livers were assessed through histopathology after 70 days of treatment. The levels of tumor necrosis factor (TNF)-? and interferon (IFN)-? were evaluated in the serum by enzyme-linked immunosorbent assay (ELISA). The expression levels of TNF-? were detected in the hepatic tissue by reverse transcription-polymerase chain reaction and western blot analysis. The activity levels of alanine aminotransferase and aspartate aminotransferase were determined in the serum by ELISA. The expression levels of laminin (LN), hyaluronic acid (HA), procollagen type III (PC-III) and type IV collagen (IV-C) were detected in the serum by radioimmunoassays. The results revealed that the mean area of the granulomas was smaller in the RvE1 intervention group compared with that in the model group. Following RvE1 treatment, the serum levels of TNF-? were lower than those in the model group, while the serum levels of IFN-? were higher compared with those in the model group. The expression levels of TNF-? were lower in the hepatic tissue following RvE1 treatment compared with those in the model group. The indicators of liver fibrosis, the levels of LN, HA, PC-III and IV-C in the serum, were lower following RvE1 treatment than those in the model group. In conclusion, RvE1 treatment may reduce the growth of granulomas, thereby slowing the process of hepatic fibrosis, and this effect may be the result of anti-inflammatory and immune system adjustment.
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Analysis of 52 Rab GTPases from channel catfish and their involvement in immune responses after bacterial infections.
Dev. Comp. Immunol.
PUBLISHED: 01-31-2014
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Rab genes, encoding a large family of monomeric G-proteins, contain over 60 members in the human genome. They have been recognized as crucial regulators for membrane trafficking including cargo sorting, vesicle formation, budding, motility, docking, fusion, secretory and endocytic pathway of host immune responses. However, little is known of the Rab gene family in teleost fish species. The development of full-length transcripts and whole genome sequences allow the identification and annotation of Rab GTPase gene family in catfish. In this study, a total of 52 Rab genes were identified from catfish cDNA and genome databases. Phylogenetic analysis assigned them into eleven subfamilies. Most Rab GTPases are conserved among vertebrates, though some of which are absent in fish genomes. Analysis of multiple RNA-seq datasets, along with real time PCR analysis revealed up-regulation of 10 Rab genes after bacterial infection. These included Rab3a, Rab4a, Rab4b, Rab5a, Rab5c, Rab7a, Rab9a, Rab11a, Rab11b, and Rab33a. Their up-regulation are temporally and spatially regulated in various tissues, but mostly induced at early stages after infection and in the gill and liver tissues, with the exception of Rab5c that is mostly up-regulated in the head kidney and trunk kidney. The complex pattern of their induced expression suggested both specific and cooperative actions of a these Rab genes in the acute immune responses to bacterial infection.
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Identification and Analysis of Genome-Wide SNPs Provide Insight into Signatures of Selection and Domestication in Channel Catfish (Ictalurus punctatus).
PLoS ONE
PUBLISHED: 01-01-2014
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Domestication and selection for important performance traits can impact the genome, which is most often reflected by reduced heterozygosity in and surrounding genes related to traits affected by selection. In this study, analysis of the genomic impact caused by domestication and artificial selection was conducted by investigating the signatures of selection using single nucleotide polymorphisms (SNPs) in channel catfish (Ictalurus punctatus). A total of 8.4 million candidate SNPs were identified by using next generation sequencing. On average, the channel catfish genome harbors one SNP per 116 bp. Approximately 6.6 million, 5.3 million, 4.9 million, 7.1 million and 6.7 million SNPs were detected in the Marion, Thompson, USDA103, Hatchery strain, and wild population, respectively. The allele frequencies of 407,861 SNPs differed significantly between the domestic and wild populations. With these SNPs, 23 genomic regions with putative selective sweeps were identified that included 11 genes. Although the function for the majority of the genes remain unknown in catfish, several genes with known function related to aquaculture performance traits were included in the regions with selective sweeps. These included hypoxia-inducible factor 1?· HIF?? ¨ and the transporter gene ATP-binding cassette sub-family B member 5 (ABCB5). HIF1?· is important for response to hypoxia and tolerance to low oxygen levels is a critical aquaculture trait. The large numbers of SNPs identified from this study are valuable for the development of high-density SNP arrays for genetic and genomic studies of performance traits in catfish.
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Hp1404, a new antimicrobial peptide from the scorpion Heterometrus petersii.
PLoS ONE
PUBLISHED: 01-01-2014
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Antimicrobial peptides have attracted much interest as a novel class of antibiotics against a variety of microbes including antibiotics resistant strains. In this study, a new cationic antimicrobial peptide Hp1404 was identified from the scorpion Heterometrus petersii, which is an amphipathic ?-helical peptide and has a specific inhibitory activity against gram-positive bacteria including methicillin-resistant Staphylococcus aureus. Hp1404 can penetrate the membrane of S. aureus at low concentration, and disrupts the cellular membrane directly at super high concentration. S. aureus does not develop drug resistance after multiple treatments with Hp1404 at sub MIC concentration, which is possibly associated with the antibacterial mechanism of the peptide. In addition, Hp1404 has low toxicity to both mammalian cells (HC?? ?=? 226.6 µg/mL and CC?? > 100 µg/mL) and balb-c mice (Non-toxicity at 80 mg/Kg by intraperitoneal injection and LD?? ?=? 89.8 mg/Kg by intravenous injection). Interestingly, Hp1404 can improve the survival rate of the MRSA infected balb-c mice in the peritonitis model. Taken together, Hp1404 may have potential applications as an antibacterial agent.
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The relationship between seven common polymorphisms from five DNA repair genes and the risk for breast cancer in northern Chinese women.
PLoS ONE
PUBLISHED: 01-01-2014
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Converging evidence supports the central role of DNA damage in progression to breast cancer. We therefore in this study aimed to assess the potential interactions of seven common polymorphisms from five DNA repair genes (XRCC1, XRCC2, XRCC3, XPA and APEX1) in association with breast cancer among Han Chinese women.
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Hydrogen sulfide offers neuroprotection on traumatic brain injury in parallel with reduced apoptosis and autophagy in mice.
PLoS ONE
PUBLISHED: 01-01-2014
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Hydrogen sulfide (H2S), a novel gaseous mediator, has been recognized as an important neuromodulator and neuroprotective agent in the central nervous system. The present study was undertaken to study the effects of exogenous H2S on traumatic brain injury (TBI) and the underlying mechanisms. The effects of exogenous H2S on TBI were examined by using measurement of brain edema, behavior assessment, propidium iodide (PI) staining, and Western blotting, respectively. Compared to TBI groups, H2S pretreatment had reduced brain edema, improved motor performance and ameliorated performance in Morris water maze test after TBI. Immunoblotting results showed that H2S pretreatment reversed TBI-induced cleavage of caspase-3 and decline of Bcl-2, suppressed LC3-II, Beclin-1 and Vps34 activation and maintained p62 level in injured cortex and hippocampus post TBI. The results suggest a protective effect and therapeutic potential of H2S in the treatment of brain injury and the protective effect against TBI may be associated with regulating apoptosis and autophagy.
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A nanomembrane-based wavelength-tunable high-speed single-photon-emitting diode.
Nano Lett.
PUBLISHED: 11-08-2013
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We demonstrate an all-electrically operated wavelength-tunable on demand single-photon source for the first time. The device consists of a light-emitting diode in the form of a semiconductor nanomembrane containing self-assembled quantum dots integrated onto a piezoelectric crystal. Triggered single photons are generated via injection of ultrashort electrical pulses into the diode, while their energy can be precisely tuned over a broad range by varying the voltage applied to the piezoelectric crystal. High speed operation of this single-photon-emitting diode up to 0.8 GHz is demonstrated. These results represent an important step toward the realization of electrically driven sources of indistinguishable photons on demand.
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Porphyrin-POSS molecular hybrids.
Chemistry
PUBLISHED: 11-01-2013
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Porphyrin-POSS hybrid: Porphyrin-POSS molecular hybrid composites (see scheme; POSS = polyhedral oligomeric silsesquioxanes) were synthesized and structurally characterized, allowing the realization of truly homogenous dispersion of basic functional building blocks between organic and inorganic components at the molecular level. These materials allow the optimization of aggregation/association behavior and thus the functional optical properties of the porphyrinato zinc compounds.
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Stereochemistry and solid-state structure of an intrinsically chiral meso-patterned porphyrin: case study by NMR and single-crystal X-ray diffraction analysis.
J. Org. Chem.
PUBLISHED: 09-24-2013
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A C1-symmerical meso-substituted ABCD-type porphyrin, [5-phenyl-10-(2-hydroxynaphthyl)-15-(4-hydroxyphenyl)porphyrinato]zinc(II) (1), has been synthesized and characterized. The molecular structure of 1 has been determined by single-crystal X-ray diffraction analysis. The complex 1 crystallizes in a triclinic system with one pair of enantiomeric molecules per unit cell. Resolution of the racemic mixture has been achieved by chiral HPLC techniques. In particular, the absolute configurations of the enantiomers have been assigned from NMR spectroscopic analysis with L-Phe-OMe as the chiral solvating agent (CSA). The assignments have also been unambiguously confirmed by single-crystal X-ray diffraction analysis. The present results suggest that the CSA-NMR anisotropy strategy is applicable for the stereochemistry determination of chiral host-guest complexes with multiple intermolecular interactions. In addition, the multiple intermolecular interactions between the enantiomerically pure porphyrin S-1 and L-Phe-OMe are proved in the solid state by single-crystal X-ray diffraction analysis.
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Highly bendable, conductive, and transparent film by an enhanced adhesion of silver nanowires.
ACS Appl Mater Interfaces
PUBLISHED: 09-11-2013
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Recently, silver nanowires (AgNWs) have attracted considerable interest for their potential application in flexible transparent conductive films (TCFs). One challenge for the commercialization of AgNW-based TCFs is the low conductivity and stability caused by the weak adhesion forces between the AgNWs and the substrate. Here, we report a highly bendable, conductive, and transparent AgNW film, which consists of an underlying poly(diallyldimethyl-ammonium chloride) (PDDA) and AgNW composite bottom layer and a top layer-by-layer (LbL) assembled graphene oxide (GO) and PDDA overcoating layer (OCL). We demonstrated that PDDA could increase the adhesion between the AgNW and the substrate to form a uniform AgNW network and could also serve to improve the stability of the GO OCL. Hence, a highly bendable, conductive, and transparent AgNW-PDDA-GO composite TCF on a poly(ethylene terephthalate) (PET) substrate with Rs ? 10 ?/sq and T ? 91% could be made by an all-solution processable method at room temperature. In addition, our AgNW-PDDA-GO composite TCF is stable without degradation after exposure to H2S gas or sonication.
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Up-conversion luminescence of gold nanospheres when excited at nonsurface plasmon resonance wavelength by a continuous wave laser.
Nano Lett.
PUBLISHED: 08-08-2013
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We show that, when gold nanospheres are excited at the red side of the surface plasmon resonance (SPR) wavelength at 592 nm by a continuous wave (CW) laser, they give substantial up-converted luminescence in the SPR wavelength range. The luminescence intensity scales as a second-order function of the excitation power, with a quantum yield ~1/50 of down-conversion luminescence when illuminated at a power of 30 MW/cm(2). The luminescence spectrum is completely different than the SPR profile, indicating a new emission mechanism possibly involving interband transitions coupled with phonons or localized vibration of neighboring gold atoms. Such luminescence is also observed to be substantial for short gold nanorods with an aspect ratio of ~2 but weak for bulk gold. This study provides new insight to the understanding of gold nanoparticle luminescence and opens a new detection scheme for gold nanoparticle-based biological imaging.
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Bulk segregant RNA-seq reveals expression and positional candidate genes and allele-specific expression for disease resistance against enteric septicemia of catfish.
BMC Genomics
PUBLISHED: 07-30-2013
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The application of RNA-seq has accelerated gene expression profiling and identification of gene-associated SNPs in many species. However, the integrated studies of gene expression along with SNP mapping have been lacking. Coupling of RNA-seq with bulked segregant analysis (BSA) should allow correlation of expression patterns and associated SNPs with the phenotypes.
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Magnetic Microstructure of Rolled-Up Single-Layer Ferromagnetic Nanomembranes.
Adv. Mater. Weinheim
PUBLISHED: 07-01-2013
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The magnetic microstructure of rolled-up magnetic nanomembranes is revealed both theoretically and experimentally. Two types of nanomembranes are considered, one with a non-magnetic spacer layer and the other without. Experimentally, by using different materials and tuning the dimensions of the rolled-up nanomembranes, domain patterns consisting of spiral-like and azimuthally magnetized domains are observed, which are in qualitative agreement with the theoretical predictions.
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Self-Grown Oxy-Hydroxide@ Nanoporous Metal Electrode for High-Performance Supercapacitors.
Adv. Mater. Weinheim
PUBLISHED: 06-30-2013
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A binder-free self-grown oxy-hydroxide@nanoporous Ni-Mn hybrid electrode with high capacitance and cyclic stability is fabricated by electrochemical polarization of a dealloyed nanoporous Ni-Mn alloy. Combined with the low material costs, high electrochemical stability, and environmentally friendly nature, this novel electrode holds great promise for applications in high-capacity commercial supercapacitors.
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MT1-MMP prevents growth inhibition by three dimensional fibronectin matrix.
Biochem. Biophys. Res. Commun.
PUBLISHED: 05-29-2013
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The extracellular microenvironment plays a key role in regulation of cellular functions and growth control. We show here that membrane-type 1 matrix metalloproteinase (MT1-MMP) acts as a growth promoter in confluent culture. When MT1-MMP was silenced in HT1080 fibrosarcoma cells, cells created three dimensional (3D) fibronectin matrix in a confluent culture, and growth of cells embedded within it was retarded. Formation of 3D fibronectin matrix initiated by MT1-MMP silencing was impeded by knockdown of either FN or integrin ??, which resulted in restoration of cell growth. When cells in 3D fibronectin matrix were treated with integrin ?? inhibitory antibody, cells underwent S phase entry. These results suggest that MT1-MMP prevents growth suppression by 3D fibronectin matrix, which is mediated through integrin ??.
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Mouse models for graft arteriosclerosis.
J Vis Exp
PUBLISHED: 05-29-2013
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Graft arteriosclerois (GA), also called allograft vasculopathy, is a pathologic lesion that develops over months to years in transplanted organs characterized by diffuse, circumferential stenosis of the entire graft vascular tree. The most critical component of GA pathogenesis is the proliferation of smooth muscle-like cells within the intima. When a human coronary artery segment is interposed into the infra-renal aortae of immunodeficient mice, the intimas could be expand in response to adoptively transferred human T cells allogeneic to the artery donor or exogenous human IFN-? in the absence of human T cells. Interposition of a mouse aorta from one strain into another mouse strain recipient is limited as a model for chronic rejection in humans because the acute cell-mediated rejection response in this mouse model completely eliminates all donor-derived vascular cells from the graft within two-three weeks. We have recently developed two new mouse models to circumvent these problems. The first model involves interposition of a vessel segment from a male mouse into a female recipient of the same inbred strain (C57BL/6J). Graft rejection in this case is directed only against minor histocompatibility antigens encoded by the Y chromosome (present in the male but not the female) and the rejection response that ensues is sufficiently indolent to preserve donor-derived smooth muscle cells for several weeks. The second model involves interposing an artery segment from a wild type C57BL/6J mouse donor into a host mouse of the same strain and gender that lacks the receptor for IFN-? followed by administration of mouse IFN-? (delivered via infection of the mouse liver with an adenoviral vector. There is no rejection in this case as both donor and recipient mice are of the same strain and gender but donor smooth muscle cells proliferate in response to the cytokine while host-derived cells, lacking receptor for this cytokine, are unresponsive. By backcrossing additional genetic changes into the vessel donor, both models can be used to assess the effect of specific genes on GA progression. Here, we describe detailed protocols for our mouse GA models.
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Effect of traditional Chinese medicine (Xiaochaihu Tang) on the expression of MMP-2 and MMP-9 in rats with endometriosis.
Exp Ther Med
PUBLISHED: 05-22-2013
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The aim of this study was to explore the effect of a traditional Chinese medicine (Xiaochaihu Tang, XCHT) on the expression of matrix metalloproteinase-2 (MMP-2) and MMP-9 in rats with endometriosis (EMs). A total of 48 specific-pathogen-free (SPF) female Sprague-Dawley (SD) rats were randomly divided into control (n=8) and EMs (n=40) groups. The EMs model was established using a surgical procedure. At 21 days, the rats with EMs were screened and divided into four subgroups (n=8): the model control, low-dose (7.5 g/kg) XCHT-treated, high-dose (15 g/kg) XCHT-treated and gestrinone-treated (0.5 mg/kg) groups. Following 21 days of treatment, the rats were sacrificed. Reverse transcription-polymerase chain reaction (RT-PCR) and western blotting were used to examine the mRNA and protein levels of MMP-2 and MMP-9 in the endometrium. The expression levels of MMP-2 and MMP-9 were significantly increased in the rats with EMs compared with those in normal rats. Moreover, XCHT was able to significantly inhibit the expression of MMP-2 and MMP-9 compared with that in the model control group. In conclusion, XCHT was able to decrease the expression of MMP-2 and MMP-9 in the ectopic endometrium. The present results may provide a potential theoretical basis for the therapy of EMs.
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microRNA-7 suppresses the invasive potential of breast cancer cells and sensitizes cells to DNA damages by targeting histone methyltransferase SET8.
J. Biol. Chem.
PUBLISHED: 05-17-2013
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SET8 (SET domain containing 8) is a histone H4 lysine 20 (H4K20)-specific monomethyltransferase in higher eukaryotes that exerts diverse functions in transcription regulation, DNA repair, tumor metastasis, and genome integrity. The activity of SET8 is tightly controlled during cell cycle through post-translational modifications, including ubiquitination, phosphorylation, and sumoylation. However, how the expression of SET8 is regulated is not fully understood. Here, we report that microRNA-7 is a negative regulator of SET8. We demonstrated that microRNA-7 inhibits H4K20 monomethylation and suppresses epithelial-mesenchymal transition and the invasive potential of breast cancer cells. We showed that microRNA-7 promotes spontaneous DNA damages and sensitizes cells to induced DNA damages. Our experiments provide a molecular mechanism for the regulation of SET8 and extend the biological function of microRNA-7 to DNA damage response, supporting the pursuit of microRNA-7 as a potential target for breast cancer intervention.
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RNA-Seq reveals expression signatures of genes involved in oxygen transport, protein synthesis, folding, and degradation in response to heat stress in catfish.
Physiol. Genomics
PUBLISHED: 04-30-2013
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Temperature is one of the most prominent abiotic factors affecting ectotherms. Most fish species, as ectotherms, have extraordinary ability to deal with a wide range of temperature changes. While the molecular mechanism underlying temperature adaptation has long been of interest, it is still largely unexplored with fish. Understanding of the fundamental mechanisms conferring tolerance to temperature fluctuations is a topic of increasing interest as temperature may continue to rise as a result of global climate change. Catfish have a wide natural habitat and possess great plasticity in dealing with environmental variations in temperature. However, no studies have been conducted at the transcriptomic level to determine heat stress-induced gene expression. In the present study, we conducted an RNA-Seq analysis to identify heat stress-induced genes in catfish at the transcriptome level. Expression analysis identified a total of 2,260 differentially expressed genes with a cutoff of twofold change. qRT-PCR validation suggested the high reliability of the RNA-Seq results. Gene ontology, enrichment, and pathway analyses were conducted to gain insight into physiological and gene pathways. Specifically, genes involved in oxygen transport, protein folding and degradation, and metabolic process were highly induced, while general protein synthesis was dramatically repressed in response to the lethal temperature stress. This is the first RNA-Seq-based expression study in catfish in response to heat stress. The candidate genes identified should be valuable for further targeted studies on heat tolerance, thereby assisting the development of heat-tolerant catfish lines for aquaculture.
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SOCS1 Prevents Graft Arteriosclerosis by Preserving Endothelial Cell Function.
J. Am. Coll. Cardiol.
PUBLISHED: 04-11-2013
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The aim of this study was to determine the role of Suppressor of Cytokine Signaling 1 (SOCS1) in graft arteriosclerosis (GA).
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Non-invasive measurement of glucose uptake of skeletal muscle tissue models using a glucose nanobiosensor.
Biosens Bioelectron
PUBLISHED: 04-05-2013
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Skeletal muscle tissues play a significant role to maintain the glucose level of whole body and any dysfunction of this tissue leads to the diabetes disease. A culture medium was created in which the muscle cells could survive for a long time and meanwhile it did not interfere with the glucose sensing. We fabricated a model of skeletal muscle tissues in vitro to monitor its glucose uptake. A nanoporous gold as a high sensitive nanobiosensor was then successfully developed and employed to detect the glucose uptake of the tissue models in this medium upon applying the electrical stimulation in a rapid, and non-invasive approach. The response of the glucose sensor was linear in a wide concentration range of 1-50 mM, with a detection limit of 3 ?M at a signal-to-noise ratio of 3.0. The skeletal muscle tissue was electrically stimulated during 24 h and glucose uptake was monitored during this period. During the first 3 h of stimulation, electrically stimulated muscle tissue consumed almost twice the amount of glucose than counterpart non-stimulated sample. In total, the glucose consumption of muscle tissues was higher for the electrically stimulated tissues compared to those without applying the electrical field.
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Boron-phenylpyrrin dyes: facile synthesis, structure, and pH-sensitive properties.
Chemistry
PUBLISHED: 04-04-2013
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Boron-phenylpyrrin dyes: In the presence of BF3?OEt2, 4-(diethylamino)salicylaldehyde reacts with substituted pyrroles to give boron-phenylpyrrin dyes, which contain a central boron-containing seven-membered ring. Upon protonation in acidic solution, the complexes, with a large Stokes shift, exhibit a color change and a unique red shift in both the electronic absorption and fluorescence emission spectra (see picture), thus rendering them new analogues of boron-dipyrrin dyes that can be used as pH sensors.
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Magnetoresistive emulsion analyzer.
Sci Rep
PUBLISHED: 03-25-2013
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We realize a magnetoresistive emulsion analyzer capable of detection, multiparametric analysis and sorting of ferrofluid-containing nanoliter-droplets. The operation of the device in a cytometric mode provides high throughput and quantitative information about the dimensions and magnetic content of the emulsion. Our method offers important complementarity to conventional optical approaches involving ferrofluids, and paves the way to the development of novel compact tools for diagnostics and nanomedicine including drug design and screening.
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Activation of coagulation, anti-coagulation, fibrinolysis and the complement system in patients with urticaria.
Asian Pac. J. Allergy Immunol.
PUBLISHED: 03-23-2013
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Recently released studies indicate that activation of blood coagulation may be involved in causing urticaria.
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An important role of matrix metalloproteinase-8 in angiogenesis in vitro and in vivo.
Cardiovasc. Res.
PUBLISHED: 03-19-2013
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Growing evidence suggests a close association of plaque angiogenesis with atherosclerotic plaque formation and progression, and an important role of matrix metalloproteinase (MMP) in angiogenesis and atherosclerosis. We attempted to investigate the functional involvements of MMP8 in angiogenesis.
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Side-by-side comparison of the biological characteristics of human umbilical cord and adipose tissue-derived mesenchymal stem cells.
Biomed Res Int
PUBLISHED: 02-28-2013
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Both human adipose tissue-derived mesenchymal stem cells (ASCs) and umbilical cord-derived mesenchymal stem cells (UC-MSCs) have been explored as attractive mesenchymal stem cells (MSCs) sources, but very few parallel comparative studies of these two cell types have been made. We designed a side-by-side comparative study by isolating MSCs from the adipose tissue and umbilical cords from mothers delivering full-term babies and thus compared the various biological aspects of ASCs and UC-MSCs derived from the same individual, in one study. Both types of cells expressed cell surface markers characteristic of MSCs. ASCs and UC-MSCs both could be efficiently induced into adipocytes, osteoblasts, and neuronal phenotypes. While there were no significant differences in their osteogenic differentiation, the adipogenesis of ASCs was more prominent and efficient than UC-MSCs. In the meanwhile, ASCs responded better to neuronal induction methods, exhibiting the higher differentiation rate in a relatively shorter time. In addition, UC-MSCs exhibited a more prominent secretion profile of cytokines than ASCs. These results indicate that although ASCs and UC-MSCs share considerable similarities in their immunological phenotype and pluripotentiality, certain biological differences do exist, which might have different implications for future cell-based therapy.
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Adsorption of 1-butyl-3-methylimidazolium chloride ionic liquid by functional carbon microspheres from hydrothermal carbonization of cellulose.
Environ. Sci. Technol.
PUBLISHED: 02-22-2013
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Functional carbonaceous material (FCM) loaded with carboxylic groups was prepared by hydrothermal carbonization of cellulose in the presence of acrylic acid. The resulting FCM was used as adsorbent for recovery of a water-soluble ionic liquid, 1-butyl-3-methyl-imidazolium chloride ([BMIM][Cl]). The FCM consisted of microspheres (100-150 nm) and had a low surface area (ca. 20 m(2)/g), but exhibited adsorption capacity comparable to that of commercial activated carbon which can be attributed to the presence of high content of polar oxygenated groups (-OH, -C?O, -COOH) as revealed by spectral analyses. Sorption of [BMIM][Cl] onto FCM adsorbent could be well-described by pseudo-second-order kinetics. Thermodynamic and adsorption isothermal analyses revealed that the adsorption process was spontaneous, exothermic, and could be described by the Freundlich adsorption model. The FCM adsorbent could be regenerated effectively and recycled for at least three times without loss of adsorption capacity. The results of this work provide a facile method for production of functional carbonaceous materials from renewable resources that can be used for treatment of aqueous streams containing small concentrations of ionic liquid, [BMIM][Cl].
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Functional involvements of heterogeneous nuclear ribonucleoprotein A1 in smooth muscle differentiation from stem cells in vitro and in vivo.
Stem Cells
PUBLISHED: 01-22-2013
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To investigate the functional involvements of heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) in smooth muscle cell (SMC) differentiation from stem cells, embryonic stem cells were cultivated on collagen IV-coated plates to allow for SMC differentiation. We found that hnRNPA1 gene and protein expression was upregulated significantly during differentiation and coexpressed with SMC differentiation markers in the stem cell-derived SMCs as well as embryonic SMCs of 12.5 days of mouse embryos. hnRNPA1 knockdown resulted in downregulation of smooth muscle markers and transcription factors, while enforced expression of hnRNPA1 enhanced the expression of these genes. Importantly, knockdown of hnRNPA1 also resulted in impairment of SMC differentiation in vivo. Moreover, we demonstrated that hnRNPA1 could transcriptionally regulate SMC gene expression through direct binding to promoters of Acta2 and Tagln genes using luciferase and chromatin immunoprecipitation assays. We further demonstrated that the binding sites for serum response factor (SRF), a well-investigated SMC transcription factor, within the promoter region of the Acta2 and Tagln genes were responsible for hnRNPA1-mediated Acta2 and Tagln gene expression using in vitro site-specific mutagenesis and luciferase activity analyses. Finally, we also demonstrated that hnRNPA1 upregulated the expression of SRF, myocyte-specific enhancer factor 2c (MEF2c), and myocardin through transcriptional activation and direct binding to promoters of the SRF, MEF2c, and Myocd genes. Our findings demonstrated that hnRNPA1 plays a functional role in SMC differentiation from stem cells in vitro and in vivo. This indicates that hnRNPA1 is a potential modulating target for deriving SMCs from stem cells and cardiovascular regenerative medicine.
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Recent advances in bioprocessing application of membrane chromatography.
Biotechnol. Adv.
PUBLISHED: 01-20-2013
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Compared to traditional chromatography using resins in packed-bed columns, membrane chromatography is a relatively new and immature bioseparation technology based on the integration of membrane filtration and liquid chromatography into a single-stage operation. Over the past decades, advances in membrane chemistry have yielded novel membrane devices with high binding capacities and improved mass transfer properties, significantly increasing the bioprocessing efficiency for purification of biomolecules. Due to the disposable nature, low buffer consumption, and reduced equipment costs, membrane chromatography can significantly reduce downstream bioprocessing costs. In this review, we discuss technological merits and disadvantages associated with membrane chromatography as well as recent bioseparation applications with a particular attention on purification of large biomolecules.
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Pathogen recognition receptors in channel catfish: III phylogeny and expression analysis of Toll-like receptors.
Dev. Comp. Immunol.
PUBLISHED: 01-17-2013
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Toll-like receptors (TLRs) were the earliest characterized and the most extensively studied pathogen recognition receptors (PRRs). The majority of tetrapod TLR orthologs have been found in teleost fish. In addition, a group of "fish-specific" TLRs have been identified. In catfish, a number of TLR-related sequences have been reported, but systematic phylogenetic analyses have not been conducted. In this study, we conducted phylogenetic and comparative analysis of 20 catfish TLR genes against their counterparts from various species. TLR25 and TLR26 are TLRs identified only in channel catfish. Phylogenetic analyses suggested that four catfish TLR genes have duplicated copies in the genome, i.e., TLR4, TLR5, TLR8, and TLR20. Six fish-specific TLRs were identified, and the vast majority of these belong to the TLR11 subfamily. In healthy catfish tissues, most of the tested TLR genes were ubiquitously expressed although expression levels varied among the 11 tested tissues. We tested nine TLRs for their expression in response to Edwardsiella ictaluri infection. They were significantly up-regulated in the spleen and liver, but down-regulated in the head kidney, suggesting their involvement in the immune responses against the intracellular bacterial pathogen in a tissue-specific manner in catfish, perhaps through rapid migration of phagocytes to infection sites.
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Geometry-induced spin-ice structures prepared by self-organization on the nanoscale.
Nanotechnology
PUBLISHED: 01-16-2013
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We use non-close packed colloidal lithography to prepare hexagonal magnetic antidot arrays with varying diameters at a period of 205 nm. Smaller antidots are attractive for applications as spin waveguides in magnonics. Larger antidots form a magnetically frustrated system, i.e. Kagome spin-ice, as we prove by magnetic force microscopy. The simple but effective approach successfully extends the limits of top-down lithography previously used to study spin-ice configurations and emergent magnetic monopoles towards smaller structures.
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The expression changes of cystathionine-?-synthase in brain cortex after traumatic brain injury.
J. Mol. Neurosci.
PUBLISHED: 01-13-2013
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Cystathionine-?-synthase (CBS) catalyzes the condensation of serine with homocysteine to form cystathionine and occupies a crucial regulatory position between the methionine cycle and the biosynthesis of cysteine by transsulfuration. It was reported that CBS was a novel marker of both differentiation and proliferation for certain cell types, suggesting that CBS represents a survival-promoting protein. However, its expression and function in the central nervous system lesion are not well understood. To investigate changes of CBS after traumatic brain injury (TBI) and its possible role, mice TBI model was established by controlled cortical impact system, and the expression and cellular localization of CBS after TBI was investigated in the present study. Western blot analysis revealed that CBS was present in normal mice brain cortex. It gradually decreased, reached a valley at the third day after TBI, and then restored to basal level. Importantly, more CBS was colocalized with neuron. In addition, Western blot detection showed that the third day postinjury was also the apoptosis peak indicated by the elevated expression of caspase-3. Importantly, immunohistochemistry analysis revealed that injury-induced expression of CBS was colabeled by Bcl-2 and had no co-localization with caspase-3. These data suggested that CBS may be implicated in the apoptosis of neuron and involved in the pathophysiology of brain after TBI.
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[Gly14]-Humanin offers neuroprotection through glycogen synthase kinase-3? inhibition in a mouse model of intracerebral hemorrhage.
Behav. Brain Res.
PUBLISHED: 01-11-2013
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Perihematomal brain edema formation and consequent cell death contribute to second brain injury resulting in severe neurological deficits and sometimes delayed fatality after intracerebral hemorrhage (ICH). [Gly14]-Humanin (HNG), a variant of Humanin (HN) in which the 14th amino acid serine is replaced with glycine, reduced Alzheimers disease-relevant insults and improved neurological deficits in an ischemia stroke model. In the study, we aimed to evaluate whether HNG posttreatment attenuated early brain injury after ICH and whether the protective effect was associated with regulation of apoptosis via phosphatidylinositol 3-kinase (PI3K)-Akt/GSK-3? signaling. Male ICR mice were subjected to infusion of Type IV collagenase (to induce ICH) of saline (for shams) into the left striatum. ICH animals received vehicle, HNG (1 or 2.5 ?g in 100 ?l saline) administration intraperitoneally 1h post injury. Compared with vehicle, HNG-2.5 ?g treatment improved neurological outcome and reduced brain edema at 24 and 72 h after surgery (P<0.05), but wortmannin (15 ?g/kg, 90 min before HNG-2.5 ?g, intravenously) obliterated the effect. HNG-2.5 ?g also reduced cell insults and injury volume at 24 and 72 h after surgery (P<0.05, vs. vehicle). Furthermore, HNG-2.5 ?g treatment increased p-Akt and Bcl-2 and decreased p-GSK-3?, cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase expressions in the ipsilateral hemisphere (P<0.05, vs. vehicle), however, the effect was reversed by wortmannin. In conclusion, HNG treatment improved functional and morphological outcomes after experimental ICH in mice and the protective effect was associated with suppressing apoptosis through PI3K-Akt/GSK-3? signaling pathway.
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A comparison study between CT angiography with 64-multislice spiral computed tomography and selective X-ray coronary angiography.
Exp Ther Med
PUBLISHED: 01-10-2013
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The aim of this study was to evaluate the diagnostic value of 64-multislice spiral computed tomography (64-MSCT) for coronary stenosis compared with selective X-ray coronary angiography (SCA). Patients with chest pain, chest tightness or coronary stenosis received SCA and they acted as the controls. The sensitivity and accuracy of 64-MSCT were analyzed as compared with SCA. Images from 64-MSCT were obtained for 95 patients. For the diagnosis of myocardial bridge, 64-MSCT coronary CT angiography (CTA) is superior to SCA. In cases of mild coronary stenosis, combined with clinical symptoms, patients may choose to receive conservative treatment instead of SCA. However, cases of moderate coronary stenosis should receive SCA to determine the diagnosis. In conclusion, no difference was observed between 64-MSCT coronary CTA and SCA in their ability to exclude true negative diagnoses and diagnosing true positives of coronary disease. The 64-MSCT coronary CTA method produces improved image quality for diagnosis of coronary stenosis and is a non-invasive, reliable and effective method for the diagnosis of the severity of coronary stenosis.
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Dynamic change of hydrogen sulfide after traumatic brain injury and its effect in mice.
Neurochem. Res.
PUBLISHED: 01-08-2013
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Hydrogen sulfide (H2S) is a lipid-soluble, endogenously produced gaseous messenger molecule collectively known as gasotransmitter. Over the last several decades, gasotransmitters have emerged as potent cytoprotective mediators in various models of tissue and cellular injury. In this study, we performed a weight-drop traumatic brain injury (TBI) model in adult mice and investigated changes of H2S and its possible role in the pathogenesis after TBI. Expression of Cystathionine-?-synthase (CBS) mRNA as H2S-producing enzymes in mouse brain was determined by reverse transcriptase-polymerase chain reaction (RT-PCR). From the results of RT-PCR, it was found that the expression of CBS was down-regulated in mouse brain cortex and hippocampus after brain injury. Western blot analysis revealed that CBS was present in normal mouse brain cortex and the hippocampus. It gradually decreased, reached its lowest level and then increased. Hydrogen sulfide in the cortex and hippocampus exhibited dynamic changes after brain injury, in parallel with CBS mRNA and protein expression. Moreover, pretreatment with the H2S donor (NaHS) could protect the neuron against the injury induced by TBI. Noticeably, the H2S donor NaHS could reduce TBI-induced injury assessed with lesion volume. These data suggested that H2S may have a therapeutic potential against neuron damage.
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A variant upstream of IFNL3 (IL28B) creating a new interferon gene IFNL4 is associated with impaired clearance of hepatitis C virus.
Nat. Genet.
PUBLISHED: 01-06-2013
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Chronic infection with hepatitis C virus (HCV) is a common cause of liver cirrhosis and cancer. We performed RNA sequencing in primary human hepatocytes activated with synthetic double-stranded RNA to mimic HCV infection. Upstream of IFNL3 (IL28B) on chromosome 19q13.13, we discovered a new transiently induced region that harbors a dinucleotide variant ss469415590 (TT or ?G), which is in high linkage disequilibrium with rs12979860, a genetic marker strongly associated with HCV clearance. ss469415590[?G] is a frameshift variant that creates a novel gene, designated IFNL4, encoding the interferon-?4 protein (IFNL4), which is moderately similar to IFNL3. Compared to rs12979860, ss469415590 is more strongly associated with HCV clearance in individuals of African ancestry, although it provides comparable information in Europeans and Asians. Transient overexpression of IFNL4 in a hepatoma cell line induced STAT1 and STAT2 phosphorylation and the expression of interferon-stimulated genes. Our findings provide new insights into the genetic regulation of HCV clearance and its clinical management.
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Fuel-free locomotion of Janus motors: magnetically induced thermophoresis.
ACS Nano
PUBLISHED: 01-04-2013
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We present fuel-free locomotion of magnetic spherical Janus motors driven by magnetically induced thermophoresis--a self-diffusive propulsion of an object in any liquid media due to a local temperature gradient. Within this approach an ac magnetic field is applied to induce thermophoretic motion of the objects via heating a magnetic cap of the particles, while an additional dc magnetic field is used to orient Janus motors and guide their motion on a long time scale. Full control over the motion is achieved due to specific properties of ultrathin 100-nm-thick Permalloy (Py, Fe??Ni?? alloys) magnetic films resulting in a topologically stable magnetic vortex state in the cap structure of Janus motors. Realized here magnetically induced thermophoretic locomotion does not require catalytic chemical reactions that imply toxic reagents. In this respect, we addressed and successfully solved one of the main shortcomings in the field of artificial motors, namely being fully controlled and remain biocompatible. Therefore, our approach is attractive for biotechnological in vitro assays and even in vivo operations, since the functioning of Janus motors offers low toxicity; it is not dependent on the presence of the fuel molecules in solution. Furthermore, the suggested magnetic ac excitation is superior compared to the previously proposed optically induced heating using lasers as it does not require transparent packaging.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.