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Find video protocols related to scientific articles indexed in Pubmed.
A regenerable cobalt oxide loaded magnetosphere catalyst from fly ash for mercury removal in coal combustion flue gas.
Environ. Sci. Technol.
PUBLISHED: 11-18-2014
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To remove Hg0 in coal combustion flue gas and eliminate secondary mercury pollution of spent catalyst, a new regenerable magnetic catalyst based on cobalt oxide loaded magnetospheres from fly ash (Co-MF) was developed. The catalyst with optimal loading 5.8% cobalt species attained approximately 95% Hg0 removal efficiency at 150? under simulated flue gas atmosphere. O2 could enhance the Hg0 removal activity of magnetospheres catalyst via Mars-Maessen mechanism. SO2 displayed inhibitive effect on Hg0 removal capacity. NO with lower concentration could promote the Hg0 removal efficiency. However, when increased the NO concentration to 300ppm, a slightly inhibitive effect of NO was observed. In the presence of 10 ppm HCl, above 95.5% Hg0 removal efficiency was attained, which was attributed to the formation of active chlorine species on the surface. H2O presented seriously inhibitive effect on Hg0 removal efficiency. Repeated oxidation - regeneration cycles demonstrated that the spent Co-MF catalyst could be regenerated effectively via thermally treated at 400? for 2h.
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Research on effect of minor bupleurum decoction of proliferation and apoptosis of esophageal cancer cell strain eca-109 cell.
Pak J Pharm Sci
PUBLISHED: 09-29-2014
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The research protocol is MTT (Methyl ThiazolylTetrazolium) method, Hoechst33342 staining method and flow cytometry detection to observe the effect of minor bupleurum decoction on proliferation inhibition and apoptosis-inducing of esophageal cancer cell strain Eca-109 cell and its purpose is to discuss the effect. The result of MTT method shows that minor buplerum decoction can obviously inhibit proliferation of esophageal cancer cell strain Eca-109 cell. Apoptosis number ofesophageal cancer cell increased with the increase of concentration of tetrandrine by the Hoechst 35528 staining experiment of cancer cell in three different concentrations. Flow cytometry detection result showed that cells in cell cycle G0/G1 of esophageal cancer cell strain Eca-109 cell increased obviously and cell in s period decreased significantly. This research proved that minor bupleurum decoction had anti-tumor effect and can influent proliferation and apoptosis of esophageal cancer cell strain Eca-109 cell.
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Research for the influence of telomerase inhibitors on myeloma cell and therapy.
Pak J Pharm Sci
PUBLISHED: 09-29-2014
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This paper aims to study the effect of telomerase inhibitors zidovudine (AZT) on cell morphology,survival rate and telomerase activity of in-vitro culture myeloma cell line (U266).It has provided experiment basis for applying telomerase inhibitors in multiple myeloma treatment. The myeloma cell line in logarithmic phase (U266) could be divided into AZT group and negative control group, which are added with 100 ?L AZT respectively and diluted into different concentrations with culture solution (1,10,100 and 1000 ?mol-L-(1)) of AZT, as well as culture solution of the same volume. After cultivating for 24, 48, 72 h, morphological changes of U266 cell is observed under optical microscope. Survival rate of cell is detected with MTT method, the change of telomerase activity is detected with TRAP-PCR-ELISA method. There is significant change in U266 cell morphology after AZT effect, their volume has been smaller and shrunken. Its shape has changed from short spindle to polygon or irregular shape, and broken away from the neighboring cells. Through comparing with control group, the survival rate of U266 cell in AZT group has decreased significantly (P<0.05), it represents time and concentration dependence. Median lethal concentration of AZT on U266 cell (IC50) is 1000?mol-L-(1).The drop in telomerase activity has decreased by 55.74% (P<0.05) through applying 1000 ?mol-L-(1) AZT on U266 cell for 72 h. AZT has significant inhibiting effect on the proliferation of myeloma cell line, and could reduce the telomerase activity of myeloma cell.
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Highly reversible and large lithium storage in mesoporous si/c nanocomposite anodes with silicon nanoparticles embedded in a carbon framework.
Adv. Mater. Weinheim
PUBLISHED: 08-28-2014
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A magnesiothermic reduction approach is designed to synthesize mesoporous Si/C nanocomposites with ultrasmall, uniform silicon nanoparticles (ca. 3 nm) embedded in a rigid mesoporous carbon framework. The resultant mesoporous Si/C nanocomposites present excellent performance with high reversible capacity, good Coulombic efficiency and rate capability, and outstanding cycling stability in lithium-ion battery applications.
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[Gravity frequency and its monitoring application of EEG spectrum in the vigilance operation].
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi
PUBLISHED: 07-22-2014
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It is an important means to study the electrical activity of the brain's nerve cells by exploring physiological information of the EEGs from the frequency domain. The gravity frequency is one of the global parameters with using this method. We used the multitaper spectrum method (MTM) spectrum estimation method of good performance to calculate the EEG spectrum and its gravity frequency of subjects under vigilance and vigilance decrement state. The results showed that the gravity frequency of vigilance state was higher than that of vigilance decrement state, the gravity frequency became smaller along with the vigilance decrement, and the location of the gravity frequency shifted to the left in the spectrum. Finally, the monitoring curve of the gravity frequency was acquired by designing an algorithm, and it was used to online monitoring vigilance operators.
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Effect of triptolide on the regulation of ATP?binding cassette transporter A1 expression in lipopolysaccharide?induced acute lung injury of rats.
Mol Med Rep
PUBLISHED: 07-21-2014
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The aim of this study was to investigate the effect of triptolide on ATP?binding cassette transporter A1 (ABCA1) expression in lipopolysaccharide (LPS)?induced acute lung injury (ALI) in rats. Thirty male Sprague Dawley rats weighing 200?250 g were randomly divided into six groups: Normal (N, n=5), Control (C, n=5), LPS (L, n=5), Triptolide 25 µg (TP1, n=5), Triptolide 50 µg (TP2, n=5) and Triptolide 100 µg (TP3, n=5). The N group was not administered anything; the C group was administered 5 ml/kg normal saline intravenously and 7.5 ml/kg 1% dimethylsulfoxide (DMSO) intraperitoneally; the L group was administered 5 mg/kg 0.1% LPS and 1% DMSO; and the TP1, TP2 and TP3 groups were separately injected with 0.1% LPS and 25, 50 or 100 µg/kg triptolide, respectively. All groups had the same liquid?injection volume. Arterial blood gases, tumor necrosis factor?? (TNF??) and ABCA1 expression and general pathology were examined following the treatments. It was found that increasing the triptolide dose in the TP1?3 groups resulted in an increase in the expression of ABCA1 mRNA and protein. As compared with the L group, the ABCA1 expression showed a significant increase in TP2 and TP3 groups (P<0.05). In addition, the expression level of TNF?? was significantly increased in the L and TP1 groups, as compared with that in the N or C groups (P<0.05). Conversely, a marked decrease in TNF?? expression was detected in the TP2 and TP3 groups, as compared with the L or TP1 groups (P<0.05). In conclusion, this study found that triptolide could promote the expression of ABCA1 mRNA and protein and inhibit other inflammatory factors during LPS?induced ALI in rats. Regulating the expression of ABCA1 may be one of the protective mechanisms of triptolide. Furthermore, triptolide?induced increases in ABCA1 expression occurred in a dose?dependent manner between 25 and 100 µg/kg.
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Enhanced sodium-ion battery performance by structural phase transition from two-dimensional hexagonal-SnS2 to orthorhombic-SnS.
ACS Nano
PUBLISHED: 07-14-2014
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Structural phase transitions can be used to alter the properties of a material without adding any additional elements and are therefore of significant technological value. It was found that the hexagonal-SnS2 phase can be transformed into the orthorhombic-SnS phase after an annealing step in an argon atmosphere, and the thus transformed SnS shows enhanced sodium-ion storage performance over that of the SnS2, which is attributed to its structural advantages. Here, we provide the first report on a SnS@graphene architecture for application as a sodium-ion battery anode, which is built from two-dimensional SnS and graphene nanosheets as complementary building blocks. The as-prepared SnS@graphene hybrid nanostructured composite delivers an excellent specific capacity of 940 mAh g(-1)and impressive rate capability of 492 and 308 mAh g(-1) after 250 cycles at the current densities of 810 and 7290 mA g(-1), respectively. The performance was found to be much better than those of most reported anode materials for Na-ion batteries. On the basis of combined ex situ Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and ex situ X-ray diffraction, the formation mechanism of SnS@graphene and the synergistic Na-storage reactions of SnS in the anode are discussed in detail. The SnS experienced a two-structural-phase transformation mechanism (orthorhombic-SnS to cubic-Sn to orthorhombic-Na3.75Sn), while the SnS2 experienced a three-structural-phase transformation mechanism (hexagonal-SnS2 to tetragonal-Sn to orthorhombic-Na3.75Sn) during the sodiation process. The lesser structural changes of SnS during the conversion are expected to lead to good structural stability and excellent cycling stability in its sodium-ion battery performance. These results demonstrate that the SnS@graphene architecture offers unique characteristics suitable for high-performance energy storage application.
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Studies of traditional Chinese medicine monomer on HeLa cell of cervical cancer.
Pak J Pharm Sci
PUBLISHED: 07-13-2014
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This paper is to study the effect of traditional Chinese medicine monomer including quercetin, curcumin and Glaucocalyxin A on Hela cell of cervical cancer. The inhibiting effect of quercetin, curcumin and Glaucocalyxin A on HeLa cells' proliferation is detected through using MTT method. Analysis for the effect of quercetin, curcumin and Glaucocalyxin A on proliferation cycle of Hela cell is performed through adopting flow cytometry. Three kinds of traditional Chinese medicine monomer can inhibit the growth of Hela cell, and they show dependent relationship between time and dose. Quercetin, curcumin and Glaucocalyxin A could inhibit cell proliferation, probably through making Hela cell be in stagnation and inducing its apoptosis.
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Histone modifications contribute to cellular replicative and hydrogen peroxide-induced premature senescence in human embryonic lung fibroblasts.
Free Radic. Res.
PUBLISHED: 03-10-2014
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Histone modifications are major post-translational mechanisms responsible for regulation of gene transcription involved in cellular senescence. By using immunofluorescence and Western blot, we showed that the global acetylated levels of histone H3 and H4 were significantly reduced in both replicative and premature senescence of human embryonic lung fibroblasts. However the whole trimethylated level of histone H4 lysine 20 was higher in senescent cells. The alterations in the mRNA and protein levels of histone acetyltransferases (HATs), histone methyltransferase (HMT), and histone deacetylases (HDACs) indicate that differential expression exists between replicative and premature senescent cells. Meanwhile, the reduced activity of HDACs was accompanied by cellular senescence. By employing the quantitative chromatin immunoprecipitation assay in detecting specific histone modifications in senescence-related genes including p53 and p16, it was demonstrated that the mRNA expression of p53 was associated with increased H4 acetylation in replicative senescence and increased H4 acetylation and trimethylation of histone H3 at lysine 4 (H3K4me3) in premature senescence. Both acetylation and trimethylation of H3 were involved in replicative senescence, while the acetylation of histone H3 and H4 was predominant in premature senescence, contributing to the mRNA expression of p16. In summary, the global hypoacetylation of histone H3 and H4 and the hypertrimethylation of histone H4 lysine 20 account for epigenetic characteristics in senescence, controlled by HATs, HMT, and HDACs differentially between replicative and premature senescence. Taken together, these findings suggest that the specific histone modifications are involved in regulating the expression of genes related to senescence of human embryonic lung fibroblasts.
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Dual-pore mesoporous carbon@silica composite core-shell nanospheres for multidrug delivery.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 02-01-2014
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Monodispersed mesoporous phenolic polymer nanospheres with uniform diameters were prepared and used as the core for the further growth of core-shell mesoporous nanorattles. The hierarchical mesoporous nanospheres have a uniform diameter of 200?nm and dual-ordered mesopores of 3.1 and 5.8?nm. The hierarchical mesostructure and amphiphilicity of the hydrophobic carbon cores and hydrophilic silica shells lead to distinct benefits in multidrug combination therapy with cisplatin and paclitaxel for the treatment of human ovarian cancer, even drug-resistant strains.
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Biphase stratification approach to three-dimensional dendritic biodegradable mesoporous silica nanospheres.
Nano Lett.
PUBLISHED: 01-31-2014
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A kind of novel uniform monodispersed three-dimensional dendritic mesoporous silica nanospheres (3D-dendritic MSNSs) has been successfully synthesized for the first time. The 3D-dendritic MSNSs can have hierarchical mesostructure with multigenerational, tunable center-radial, and dendritic mesopore channels. The synthesis was carried out in the heterogeneous oil-water biphase stratification reaction system, which allowed the self-assembly of reactants taking place in the oil-water interface for one-pot continuous interfacial growth. The average pore size of each generation for the 3D-dendritic MSNSs can be adjusted from 2.8 to 13 nm independently, which can be controlled by the varied hydrophobic solvents and concentration of silica source in the upper oil phase. The thickness of each generation can be tuned from ? 5 to 180 nm as desired, which can be controlled by the reaction time and amount of silica source. The biphase stratification approach can also be used to prepare other core-shell and functional mesoporous materials such as Au nanoparticle@3D-dendritic MSNS and Ag nanocube@3D-dendritic MSNS composites. The 3D-dendritic MSNSs show their unique advantage for protein loading and releasing due to their tunable large pore sizes and smart hierarchical mesostructures. The maximum loading capacity of bovine ?-lactoglobulin with 3D-dendritic MSNSs can reach as high as 62.1 wt % due to their large pore volume, and the simulated protein releasing process can be tuned from 24 to 96 h by flexible mesostructures. More importantly, the releasing rates are partly dependent on the hierarchical biodegradation, because the 3D-dendritic MSNSs with larger pore sizes have faster simulated biodegradation rates in simulated body fluid. The most rapid simulated biodegradation can be finished entirely in 24 h, which has been greatly shortened than two weeks for the mesoporous silica reported previously. As the inorganic mesoporous materials, 3D-dendritic MSNSs show excellent biocompatibility, and it would have a hopeful prospect in the clinical applications.
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Mesoporous silica-coated plasmonic nanostructures for surface-enhanced Raman scattering detection and photothermal therapy.
Adv Healthc Mater
PUBLISHED: 01-26-2014
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The design and fabrication of core-shell and yolk-shell nanostructures with surface plasmon resonance (SPR)-active center protected by permeable mesoporous channels can raise the new vitality into the catalysis and biological applications. Hybrid plasmonic-mesoporous silica nanocarriers consisting of Ag and Au-Ag alloy nanoparticles are fabricated through spatially confined galvanic replacement approach. The plasmonic absorption peaks can be finely controlled to the near-infrared (NIR) region (500-790 nm) that is beneficial for tissue transmittance. The mesoporous silica shell facilitates also protection of Au-Ag cores and affords the channels between the exterior and interior capsule environments, thereby endowing the multiple applications. In the present work, it is successfully demonstrated that mesoporous silica-coated Au-Ag alloy core-shell and yolk-shell nanocarriers can serve as good substrates for surface-enhanced Raman scattering (SERS) detection. The SERS signal intensities of nanocarriers are highly dependent on the SPR peaks and the contents of gold. Simultaneously, the synthesized Au-Ag@mSiO2 nanocarriers with SPR peak at ?790 nm can be applied in NIR-sensitive SERS detection and photothermal therapy.
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Both PAR1 and PAR2 Promote Seedling Photomorphogenesis in Multiple Light Signaling Pathways.
Plant Physiol.
PUBLISHED: 12-12-2013
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Arabidopsis seedlings undergo photomorphogenesis in the light and etiolation in the dark. Light-activated photoreceptors transduce the light signals through a series of photomorphogenesis promoting or repressing factors to modulate many developmental processes in plants, such as photomorphogenesis and shade avoidance. CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) is a conserved RING finger E3 ubiquitin ligase, which mediates degradation of several photomorphogenesis promoting factors, including ELONGATED HYPOCOTYL5 (HY5) and LONG HYPOCOTYL IN FAR-RED1 (HFR1), through a 26S proteasome-dependent pathway. PHYTOCHROME RAPIDLY REGULATED 1 (PAR1) was first detected as an early repressed gene in both phytochrome (phy) A-mediated far-red (FR) and phyB-mediated red (R) signaling pathways, and subsequent studies showed that both PAR1 and PAR2 are negative factors of shade avoidance in Arabidopsis. However, the role of PAR1 and PAR2 in seedling de-etiolation and their relationships with other photomorphogenesis promoting and repressing factors are largely unknown. Here, we confirmed that both PAR1 and PAR2 redundantly enhance seedling de-etiolation in multiple photoreceptor signaling pathways. Their transcript abundances are repressed by phyA, phyB, and cryptochrome 1 (CRY1) under FR, R, and blue (B) light conditions, respectively. Both PAR1 and PAR2 act downstream of COP1, and COP1 mediates the degradation of PAR1 and PAR2 through the 26S proteasome pathway. Both PAR1 and PAR2 act in a separate pathway from HY5 and HFR1 under different light conditions, except for sharing in the same pathway with HFR1 under FR light. Together, our results substantiate that PAR1 and PAR2 are positive factors functioning in multiple photoreceptor signaling pathways during seedling de-etiolation.
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Large pore mesostructured cellular silica foam coated magnetic oxide composites with multilamellar vesicle shells for adsorption.
Chem. Commun. (Camb.)
PUBLISHED: 11-28-2013
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Herein, large pore mesostructured cellular silica foam coated magnetic oxide composites (MO@MCFs) with multilamellar vesicle shells (MO@MLVs) were obtained, which exhibited a large pore (>10 nm), strong magnetic response (38 emu g(-1)), excellent protein adsorption and slow drug-release capacity.
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Sol-Gel Design Strategy for Ultradispersed TiO2 Nanoparticles on Graphene for High-Performance Lithium Ion Batteries.
J. Am. Chem. Soc.
PUBLISHED: 11-25-2013
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The rational design and controllable synthesis of strongly coupled inorganic/graphene hybrids represents a long-standing challenge for developing advanced catalysts and energy-storage materials. Here, we report a simple sol-gel method toward creating ultradispersed TiO2 nanoparticles on graphene with an unprecedented degree of control based on the precise separation and manipulation of nanoparticles nucleated, grown, anchored, and crystallized and the reduction of graphene oxide (GO). The hybrid materials show ultradispersed anatase nanoparticles (?5 nm), ultrathin thickness (?3 layers), and a high surface area of ?229 m(2)/g and exhibit a high specific capacity of ?94 mA h g(-1) at ?59 C, which is twice as that of mechanically mixed composites (?41 mA h g(-1)), demonstrating the potential of strongly synergistic coupling effects for advanced functional systems.
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[Profile of P66SHC expression and histone modifications in replicative cell senescence and oxidative-stress induced premature senescence].
Wei Sheng Yan Jiu
PUBLISHED: 11-14-2013
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To study the profile of P66SHc expression and histone modifications in replicatively senescenct cells and oxidative-stress inducing premature senescenct cells.
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The relationship between dietary vitamin A intake and the levels of sialic acid in the breast milk of lactating women.
J. Nutr. Sci. Vitaminol.
PUBLISHED: 09-26-2013
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Sialic acid (SA) is an important nutrient but few studies have examined the link between dietary intake and breast milk sialic acid. The purpose of this observational study was to assess the potential relationship between human breast milk sialic acid levels and dietary nutrition intake 40 d postpartum. The study population included 90 healthy women who were lactating. Human breast milk SA concentrations were measured using fluorescence detector-high performance liquid chromatography (HPLC-FLD) analysis and nutritional intake was estimated by a computerized validated food frequency questionnaire. SA in human breast milk was bound to free oligosaccharides (82.35%), protein (15.27%) and free sialic acid (2.37%). The findings of this study indicate that subjects with higher milk SA levels showed statistically higher levels of vitamin A compared with subjects with lower SA levels (423.48±172.29 vs. 602.22±126.46 ?g/d, p=0.000). In addition, there was a certain association (standardized coefficients=0.713; p=0.000) between breast milk SA and vitamin A intake in healthy young subjects. This study demonstrated that dietary vitamin A intake has a certain relationship with breast milk SA concentrations. This may be attributed to the influence of vitamin A on sialic acid glycoprotein and sialic acid mucopolysaccharide in the human body or the common food sources for vitamin A and sialic acid. Additional study is required to further investigate this relationship.
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Triptolide ameliorates lipopolysaccharide-induced acute lung injury in rats.
Eur. J. Med. Res.
PUBLISHED: 09-25-2013
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Acute lung injury (ALI) is a serious clinical syndrome with a high rate of mortality. In this study, the effects of triptolide on lipopolysaccharide (LPS)-induced ALI in rats were investigated.
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A microfluidic device for rapid screening of chemotaxis-defective Caenorhabditis elegans mutants.
Biomed Microdevices
PUBLISHED: 08-24-2013
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Behavioral Caenorhabditis elegans mutants are sought for the purposes of neurobiological research. Until now, large numbers of worms with neuronal defects have been obtained through mutagenesis techniques. However, the existing screening procedures are not only time-consuming and low-throughput, but also tedious and labor-intensive. Therefore, developing a rapid and convenient method to overcome these difficulties is necessary. The present study demonstrates for the first time a microdevice for the rapid screening of chemotaxis-defective mutants based on their chemotactic response. The microchip is capable of automatic introduction, local immobilization, and controllable generation of concentration gradients during the screening assays. With this device, six C. elegans behavioral assays can be performed using various attractants without requiring anesthetics for local capture, and ten mutants are effectively isolated from 10(4) mutagenized worms in 100 min. The microfluidics-based method is robust enough to sort the chemotaxis-defective worms with 91 % accuracy from a large population of wild type animals during a mutagenesis screen.
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The control of CD8+ T cell responses is preserved in perforin-deficient mice and released by depletion of CD4+CD25+ regulatory T cells.
J. Leukoc. Biol.
PUBLISHED: 07-24-2013
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Immune suppression by Treg has been demonstrated in a number of models, but the mechanisms of this suppression are only partly understood. Recent work has suggested that Tregs may suppress by directly killing immune cell populations in vivo in a perforin- and granzyme B-dependent manner. To establish whether perforin is necessary for the regulation of immune responses in vivo, we examined OVA-specific CD8(+) T cell responses in WT and PKO mice immunized with OVA and ?-GalCer and the expansion of WT OT-I CD8(+) T cells adoptively transferred into WT or PKO mice immunized with DC-OVA. We observed similar expansion, phenotype, and effector function of CD8(+) T cells in WT and PKO mice, suggesting that CD8(+) T cells were subjected to a similar amount of regulation in the two mouse strains. In addition, when WT and PKO mice were depleted of Tregs by anti-CD25 mAb treatment before DC-OVA immunization, CD8(+) T cell proliferation, cytotoxicity, and cytokine production were increased similarly, suggesting a comparable involvement of CD25(+) Tregs in controlling T cell proliferation and effector function in these two mouse strains. These data suggest that perforin expression is not required for normal immune regulation in these models of in vivo CD8(+) T cell responses induced by immunization with OVA and ?-GalCer or DC-OVA.
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Increased numbers of monocyte-derived dendritic cells during successful tumor immunotherapy with immune-activating agents.
J. Immunol.
PUBLISHED: 07-15-2013
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Local treatment with selected TLR ligands or bacteria such as bacillus Calmette-Guérin increases antitumor immune responses and delays tumor growth. It is thought that these treatments may act by activating tumor-associated dendritic cells (DCs), thereby supporting the induction of antitumor immune responses. However, common parameters of successful immune activation have not been identified. We used mouse models to compare treatments with different immune-activating agents for the ability to delay tumor growth, improve priming of tumor-specific T cells, and induce early cytokine production and DC activation. Treatment with polyinosinic-polycytidylic acid or a combination of monosodium urate crystals and Mycobacterium smegmatis was effective at delaying the growth of s.c. B16 melanomas, orthotopic 4T1 mammary carcinomas, and reducing 4T1 lung metastases. In contrast, LPS, monosodium urate crystals, or M. smegmatis alone had no activity. Effective treatments required both NK1.1(+) and CD8(+) cells, and resulted in increased T cell priming and the infiltration of NK cells and CD8(+) T cells in tumors. Unexpectedly, both effective and ineffective treatments increased DC numbers and the expression of costimulatory molecules in the tumor-draining lymph node. However, only effective treatments induced the rapid appearance of a population of monocyte-derived DCs in the draining lymph node, early release of IL-12p70 and IFN-?, and low IL-10 in the serum. These results suggest that the activation of existing DC subsets is not sufficient for the induction of antitumor immune responses, whereas early induction of Th1 cytokines and monocyte-derived DCs are features of successful activation of antitumor immunity.
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An integrated microfluidic platform for evaluating in vivo antimicrobial activity of natural compounds using a whole-animal infection model.
Lab Chip
PUBLISHED: 07-03-2013
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The nematode Caenorhabditis elegans is a useful model host for pathogenesis research that can be infected by a large number of human pathogens. Conventionally, nematode-pathogen infection assays are mainly performed on agar medium which are labor-intensive and time-consuming. To overcome these challenges, we develop for the first time an integrated microfluidic device for evaluating in vivo antimicrobial activity of natural compounds, which allows infection and anti-infection assays to be sequentially and automatically carried out in liquid medium. The device consists of a worm dispenser with 32 trap-construction chambers and concentration gradient generators, in which the processes of introduction, dispensation, confinement of worms in the chamber and drug delivery to the chamber can be integrated into a single device. In addition, the operation of the device is simple and does not require any expensive robotic fluid handling systems to dispense samples. To demonstrate the ability of this device, we devise an on-line screening experiment using a Caenorhabditis elegans-Staphylococcus aureus infection model and characterize the survival rate of the infected worms treated with antibiotics. Then, we applied the system to evaluate the antibacterial activity of several components of rhubarb: aloe-emodin, rhein and emodin at various concentrations. The device is able to load uniform worms into each chamber within 10 min and then generate various chemical concentrations automatically and simultaneously. Furthermore, the on-chip method only requires 6 h to establish the infection model and 48 h to perform the subsequent treatments. Based on the excellent advantages and scalable properties of microfluidics, the microfluidic platform holds a great potential in high-throughput screening for antimicrobials.
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Fluorimetric urease inhibition assay on a multilayer microfluidic chip with immunoaffinity immobilized enzyme reactors.
Anal. Biochem.
PUBLISHED: 06-02-2013
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We fabricated a three-layer polydimethylsiloxane (PDMS)-based microfluidic chip for realizing urease inhibition assay with sensitive fluorescence detection. Procedures such as sample prehandling, enzyme reaction, reagent mixing, fluorescence derivatization, and detection can be readily carried out. Urease reactors were prepared by adsorption of rabbit immunoglobulin G (IgG) and immunoreaction with urease-conjugated goat anti-rabbit IgG. Acetohydroxamic acid (AHA) as a competitive inhibitor of urease was tested on the chip. Microfluidically generated gradient concentrations of AHA with substrate (urea) were loaded into urease reactors. After incubation, the produced ammonia was transported out of reactors and then reacted with o-phthalaldehyde (OPA) to generate fluorescent products. Urease inhibition was indicated by a decrease in fluorescence signal detected by microplate reader. The IC50 value of AHA was determined and showed good agreement with that obtained in microplate. The presented device combines several steps of the analytical process with advantages of low reagent consumption, reduced analysis time, and ease of manipulation. This microfluidic approach can be extended to the screening of inhibitory compounds in drug discovery.
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Usefulness of real-time 3-dimensional echocardiography to identify and quantify left ventricular dyssynchrony in patients with Kawasaki disease.
J Ultrasound Med
PUBLISHED: 05-30-2013
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The role of left ventricular (LV) dyssynchrony in Kawasaki disease is unknown. This study sought to establish values for real-time 3-dimensional (3D) echocardiographically derived LV dyssynchrony parameters and identify and quantify LV dyssynchrony in patients with Kawasaki disease.
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Arabidopsis phytochrome B promotes SPA1 nuclear accumulation to repress photomorphogenesis under far-red light.
Plant Cell
PUBLISHED: 01-31-2013
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Phytochrome A (phyA) is the primary photoreceptor mediating deetiolation under far-red (FR) light, whereas phyB predominantly regulates light responses in red light. SUPPRESSOR OF PHYA-105 (SPA1) forms an E3 ubiquitin ligase complex with CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1), which is responsible for the degradation of various photomorphogenesis-promoting factors, resulting in desensitization to light signaling. However, the role of phyB in FR light signaling and the regulatory pathway from light-activated phytochromes to the COP1-SPA1 complex are largely unknown. Here, we confirm that PHYB overexpression causes an etiolation response with reduced ELONGATED HYPOCOTYL5 (HY5) accumulation under FR light. Notably, phyB exerts its nuclear activities and promotes seedling etiolation in both the presence and absence of phyA in response to FR light. PhyB acts upstream of SPA1 and is functionally dependent on it in FR light signaling. PhyB interacts and forms a protein complex with SPA1, enhancing its nuclear accumulation under FR light. During the dark-to-FR transition, phyB is rapidly imported into the nucleus and facilitates nuclear SPA1 accumulation. These findings support the notion that phyB plays a role in repressing FR light signaling. Activity modulation of the COP1-SPA E3 complex by light-activated phytochromes is an effective and pivotal regulatory step in light signaling.
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Chlorophyll Deficiency in the Maize elongated mesocotyl2 Mutant Is Caused by a Defective Heme Oxygenase and Delaying Grana Stacking.
PLoS ONE
PUBLISHED: 01-01-2013
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Etiolated seedlings initiate grana stacking and chlorophyll biosynthesis in parallel with the first exposure to light, during which phytochromes play an important role. Functional phytochromes are biosynthesized separately for two components. One phytochrome is biosynthesized for apoprotein and the other is biosynthesized for the chromophore that includes heme oxygenase (HO).
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Core-shell Ag@SiO2@mSiO2 mesoporous nanocarriers for metal-enhanced fluorescence.
Chem. Commun. (Camb.)
PUBLISHED: 10-04-2011
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A novel mesoporous nanocarrier consisting of a silver core, a silica spacer with controlled thickness and a fluorophores-loaded mesoporous silica shell was fabricated for the metal-enhanced fluorescence (MEF) and Förster resonance energy transfer (FRET) effects.
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Hydrothermal etching assisted crystallization: a facile route to functional yolk-shell titanate microspheres with ultrathin nanosheets-assembled double shells.
J. Am. Chem. Soc.
PUBLISHED: 09-15-2011
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We report a facile "hydrothermal etching assisted crystallization" route to synthesize Fe(3)O(4)@titanate yolk-shell microspheres with ultrathin nanosheets-assembled double-shell structure. The as-prepared microspheres possess a uniform size, tailored shell structure, good structural stability, versatile ion-exchange capability, high surface area, large magnetization, and exhibit a remarkable catalytic performance.
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Synthesis of well-dispersed layered double hydroxide core@ordered mesoporous silica shell nanostructure (LDH@mSiO?) and its application in drug delivery.
Nanoscale
PUBLISHED: 08-22-2011
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We demonstrate an efficient synthesis of novel layered double hydroxide mesoporous silica core-shell nanostructures (LDH@mSiO(2)) that have a hexagonal MgAl-LDH nanoplate core and an ordered mesoporous silica shell with perpendicularly oriented channels via a surfactant-templating method. Transmission electron microscopy, X-ray diffraction and N(2) sorption analyses confirmed that the obtained nanostructures have uniform accessible mesopores (?2.2 nm), high surface area (?430 m(2) g(-1)), and large pore volume (?0.22 cm(3) g(-1)). Investigations of drug release and bio-imaging showed that this material has a slow release effect of ibuprofen and good biocompatibility. This work provides an economical approach to fabricate LDH@mSiO(2) core-shell nanostructures, which may have great potential in broad drug delivery and hyperthermia therapy applications.
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Rare earth metal bis(amide) complexes bearing amidinate ancillary ligands: synthesis, characterization, and performance as catalyst precursors for cis-1,4 selective polymerization of isoprene.
Dalton Trans
PUBLISHED: 02-14-2011
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A family of rare earth metal bis(amide) complexes bearing monoanionic amidinate [RC(N-2,6-Me(2)C(6)H(3))(2)](-) (R = cyclohexyl (Cy), phenyl (Ph)) as ancillary ligands were synthesized and characterized. One-pot salt metathesis reaction of anhydrous LnCl(3) with one equivalent of amidinate lithium [RC(N-2,6-Me(2)C(6)H(3))(2)]Li, following the introduction of two equivalents of NaN(SiMe(3))(2) in THF at room temperature afforded the neutral and unsolvated mono(amidinate) rare earth metal bis(amide) complexes [RC(N-2,6-Me(2)C(6)H(3))(2)]Y[N(SiMe(3))(2)](2) (R = Cy (1); R = Ph (2)), and the "ate" mono(amidinate) rare earth metal bis(amide) complex [CyC(N-2,6-Me(2)C(6)H(3))(2)]Lu[N(SiMe(3))(2)](2)(?-Cl)Li(THF)(3) (3) in 61-72% isolated yields. These complexes were characterized by elemental analysis, NMR spectroscopy, FT-IR spectroscopy, and X-ray single crystal diffraction. Single crystal structural determination revealed that the central metal in complexes 1 and 2 adopts a distorted tetrahedral geometry, and in complex 3 forms a distorted trigonal bipyramidal geometry. In the presence of AlMe(3), and in combination with one equimolar amount of [Ph(3)C][B(C(6)F(5))(4)], complexes 1 and 2 showed high activity towards isoprene polymerization to give high molecular weight polyisoprene (M(n) > 10(4)) with good cis-1,4 selectivity (>90%).
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Facile synthesis of highly stable and well-dispersed mesoporous ZrO(2)/carbon composites with high performance in oxidative dehydrogenation of ethylbenzene.
Phys Chem Chem Phys
PUBLISHED: 07-28-2010
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Highly ordered mesoporous ZrO(2)/carbon (FDU-15) composites have been synthesized via a facile evaporation induced triconstituent co-assembly (EISA) approach by using Pluronic F127 as a template and zirconium oxychloride octahydrate and resol as Zr and carbon sources. The synthesized mesoporous composites exhibit a highly ordered two-dimensional (2-D) hexagonal mesostructure with relatively high specific surface areas (up to 947 m(2) g(-1)), pore sizes around 3.8 nm and high pore volumes (up to 0.71 cm(3) g(-1)). The results clearly show that the crystalline zirconia nanoparticles (ca. 1.9-3.9 nm) are well-dispersed in amorphous matrices of the ordered mesoporous carbon FDU-15 materials, which construct the nanocomposites. The ordered mesostructures of the obtained ZrO(2)/FDU-15 composites can be well-retained even at the high pyrolysis temperature (up to 900 degrees C), suggesting a high thermal stability. The zirconia content of the ZrO(2)/FDU-15 composites can be tunable in a wide range (up to 47%). Moreover, the resultant mesoporous ZrO(2)/FDU-15 composites exhibit high catalytic activity in oxidative dehydrogenation (ODH) of ethylbenzene (EB) to styrene (ST), with high ethylbenzene conversion (59.6%) and styrene selectivity (90.4%), which is mainly attributed to the synergistic catalytic effect between the oxygen-containing groups located on the carbon pore walls and weakly basic sites of the nanocrystalline ZrO(2). Furthermore, the high specific surface areas and opening pore channels are also responsible for their high catalytic activity. Therefore, it is a very promising catalyst material in styrene production on an industrial scale.
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Epigenetic enhancement of p66Shc during cellular replicative or premature senescence.
Toxicology
PUBLISHED: 07-19-2010
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The cytoplasmic protein p66Shc is expressed in a wide range of cell types, initially believed to be involved in signaling pathways that regulate cell growth and oxidative stress. Here the epigenetic alterations in the promoter of p66Shc were investigated in replicative senescence and in premature senescence induced by hydrogen peroxide in human embryonic pulmonary fibroblast cells. In both cases p66Shc expression was elevated compared to that seen in growing cultures. However, methylation-specific PCR and bisulfite sequencing revealed that the CpG sites were hypermethylated in all cultures. In addition, quantitative chromatin immunoprecipitation showed increased histone H4 acetylation and histone H3 Lys-4 methylation during replicative senescence, while the increased acetylation of histone H3 and H4, as well as increased H3 Lys-4 methylation, was seen in premature senescence persistence. These findings suggest that histone modifications of p66Shc might be the molecular event in cellular senescence. Taken together, the epigenetic enhancement of p66Shc is associated with the specifically increased histone acetylation and methylation, which may contribute to cellular replicative senescence or premature senescence.
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Tibia tumor-induced cancer pain involves spinal p38 mitogen-activated protein kinase activation via TLR4-dependent mechanisms.
Brain Res.
PUBLISHED: 02-24-2010
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Molecular mechanisms underlying bone cancer pain are poorly understood. Recently, p38 mitogen-activated protein kinase (MAPK) activation was shown to play a major role not only in the production of proinflammatory cytokines but also in the progression of inflammatory and neuropathic pain. We have demonstrated that tactile allodynia and spontaneous pain of female rats with tibia tumors were correlated with the increase of both phosphorylated-p38MAPK (p-p38MAPK) and proinflammatory cytokines (IL-1beta and TNF-alpha) in the spinal cord 6 days after Walker 256 cells inoculation. This change was specific to bone cancer pain because rats without tibia tumors failed to show such an increase. On the other hand, a 3-day administration [4 microg/rat/day, intrathecally (i.t.)] of 4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole (SB203580), an inhibitor of p38MAPK, could suppress tactile allodynia and spontaneous pain of the bone cancer pain rats and decrease the phosphorylation of p38 as well as the expression of IL-1beta and TNF-alpha. To characterize the cellular events upstream of p38MAPK, we have examined the role of the toll-like receptor 4 (TLR4), which had been suggested to be involved in pain hypersensitivity. We found that prolonged knockdown of TLR4 during the 3-day administration of TLR4 small interfering RNA (siRNA; 2 microg/rat/day, i.t.) could attenuate hyperalgesia developed by Walker 256 cells inoculation and decrease the phosphorylation of p38 as well as the increase of IL-1beta and TNF-alpha expression. These results demonstrate that TLR4-dependent phosphorylation of p38MAPK in spinal cord of rats might contribute to the development and maintenance of bone cancer pain, and p38MAPK and TLR4 would possibly be the potential targets for pain therapy.
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Mesoporous silica encapsulating upconversion luminescence rare-earth fluoride nanorods for secondary excitation.
Langmuir
PUBLISHED: 02-04-2010
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Mesoporous silica encapsulating upconversion luminescence NaYF(4) nanorods with uniform core-shell structures have been successfully synthesized by the surfactant-assistant sol-gel process. The thickness of ordered mesoporous silica shells can be adjusted from 50 to 95 nm by varying the amount of hydrolyzed silicate oligomer precursors from tetraethyl orthosilicate (TEOS), which further influences the BET surface area, pore volume, and the luminescence intensity. After coated with mesoporous silica shells, the hydrophobic nanorods is rendered to hydropholic simultaneously. The obtained beta-NaYF(4)@SiO(2)@mSiO(2) core-shell nanorods possess high surface area (71.2-196 m(2) g(-1)), pore volume (0.07-0.17 cm(3) g(-1)), uniform pore size distribution (2.3 nm), and accessible channels. Furthermore, the uniform core-shell nanorods show strong upconversion luminescence property similar to the hexagonal upconversion cores. The open mesopores can not only provide convenient transmission channels but also offer the huge location for accommodation of large molecules, such as fluorescent dyes and quantum dots. The secondary-excitation fluorescence of Rhodamine B is generated from the upconversion rare-earth fluoride nanorods cores to the fluorescent dyes loaded in the mesoporous silica shells.
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Direct triblock-copolymer-templating synthesis of ordered nitrogen-containing mesoporous polymers.
J Colloid Interface Sci
PUBLISHED: 08-13-2009
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Ordered nitrogen-containing mesoporous carbonaceous polymers have been synthesized via a direct triblock-copolymer-templating process by using soluble, low-molecular-weight urea-phenol-formaldehyde (UPF) resin as an organic precursor and amphiphilic triblock copolymer Pluronic F127 as a template. Characterization using small-angle X-ray scattering (SAXS), N(2) sorption, transmission electron microscopy (TEM), elemental analysis, thermogravimetric analysis (TG), Fourier transform infrared (FTIR), and water adsorption techniques reveals that the obtained nitrogen-containing mesoporous polymers possess ordered structures, high surface areas (385-420 m(2)/g), large pore sizes (3.1-3.6nm) and pore volumes (0.25-0.44cm(3)/g), and high nitrogen content (2.69-2.94%). Various mesostructures, such as two-dimensional (2-D) hexagonal (space group, p6mm) and 3-D body-centered cubic (Im3 m) symmetries, can be obtained by simply adjusting the mass ratio of UPF/F127. The content of nitrogen in the mesoporous polymers can also be easy varied by changing the amount of urea and the reaction time of UPF resin precursors. Compared with the nitrogen-free mesoporous polymer, the obtained mesoporous carbonaceous polymers show a more hydrophilic nature and thus evidently higher water adsorption capacity. The presence of nitrogen groups can also significantly improve the adsorption performance of Fe(III) ions.
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[Study on the replicative and premature senescence induced by hydrogen peroxide of human embryonic lung fibroblasts].
Wei Sheng Yan Jiu
PUBLISHED: 05-05-2009
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To study both cellular replicative and prematuce senescence induced by hydrogen peroxide (H2O2) of human embryonic lung fibroblasts (HEFs).
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Severe vitamin D-deficiency and the health of North China children.
Matern Child Health J
PUBLISHED: 04-01-2009
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To determine the health and nutritional status of rural Chinese children ages 12-24 months.
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Inefficient boosting of antitumor CD8(+) T cells by dendritic-cell vaccines is rescued by restricting T-cell cytotoxic functions.
Oncoimmunology
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Dendritic cells (DCs) are powerful activators of primary and secondary immune responses and have promising activity as anticancer vaccines. However, various populations of immune cells, including natural killer cells, regulatory T cells and especially cytotoxic T lymphocytes (CTLs), can inhibit DC function through cytotoxic clearance. Spontaneous tumor-specific CTL responses are frequently observed in patients before immunotherapy, and it is unclear how such pre-existing responses may affect DC vaccines. We used an adoptive transfer model to show that DC vaccination fail to induce the expansion of pre-existing CTLs or increase their production of interferon ? (IFN?). The expansion and effector differentiation of naïve host CD8(+) T cells was also suppressed in the presence of CTLs of the same specificity. Suppression was caused by the cytotoxic functions of the adoptively transferred CTLs, as perforin-deficient CTLs could respond to DC vaccination by expanding and increasing IFN? production. Proliferation and effector differentiation of host CD8(+) T cells as well as resistance to tumor challenge were also significantly increased. Expression of perforin by antitumor CTLs was critical in regulating the survival of vaccine DCs, while FAS/FASL and TRAIL/DR5 had a significant, but comparatively smaller, effect. We conclude that perforin-expressing CTLs can suppress the activity of DC-based vaccines and prevent the expansion of naïve and memory CD8(+) T cells as well as antitumor immune responses. We suggest that, paradoxically, temporarily blocking the cytotoxic functions of CTLs at the time of DC vaccination should result in improved vaccine efficiency and enhanced antitumor immunity.
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Quantification of lactate in synovia by microchip with contactless conductivity detection.
Anal. Biochem.
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This article describes the determination of lactate in synovia by microchip capillary electrophoresis (MCE) integrated with contactless conductivity detection (CCD). The optimal running buffer consists of 10mM tris(hydroxymethyl)aminomethane, 1 mM HCl, and 0.1 mM hexadecyltrimethylammonium bromide (pH 9.1). The quantitative measurement of lactate in dilute synovia samples can be finished in less than 40s. The results indicated that the peak area had a good linear relationship with lactate concentration in the range of 20 to 1000 ?M, and the correlation coefficient was 0.9984. The average recovery was from 96.6% to 106.1%, and the interday relative standard deviation was less than 4.0% (n=6). The limit of detection (signal/noise=3) reached 6.5 ?M. To validate the assay results, we compared the current method with the high-performance liquid chromatography method by measuring lactate in synovia samples. The data analysis verified that there was no significant difference between the two methods. Due to significant features such as low cost, integration, and miniaturization, the MCE-CCD method may have great potential in clinical diagnosis.
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Silica nanoparticles capture atmospheric lead: implications in the treatment of environmental heavy metal pollution.
Chemosphere
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Lead (Pb) contamination in the air is a severe global problem, most notably in China. Removal of Pb from polluted air remains a significant challenge. It is unclear what potential effects silica nanoparticles (SiNPs) exposure can have on atmospheric Pb. Here we first characterized the features of SiNPs by measuring the particle size, zeta potential and the specific surface area of SiO(2) particles using a Nicomp 380/ZLS submicron particle sizer, the Brunauer-Emmett-Teller (BET) method and transmission electronic microscopy (TEM). We measured the content of the metal Pb adsorbed by SiNPs exposed to two Pb polluted electric battery plants using inductively coupled plasma mass spectrometry (ICP-MS). It is found that SiNPs exposed to two Pb polluted electric battery plants absorb more atmospheric Pb compared to either blank control or micro-sized SiO(2) particles in a time-dependent manner. This is the first study demonstrating that SiNPs exposure can absorb atmospheric Pb in the polluted environment. These novel findings indicate that SiNPs have potential to serve as a significant adsorbent of Pb from industrial pollution, implicating a potentially novel application of SiNPs in the treatment of environmental heavy metal pollution.
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One-step hydrothermal synthesis of carboxyl-functionalized upconversion phosphors for bioapplications.
Chemistry
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In this paper, we report a facile one-step hydrothermal method to synthesize phase-, size-, and shape-controlled carboxyl-functionalized rare-earth fluorescence upconversion phosphors by using a small-molecule binary acid, such as malonic acid, oxalic acid, succinic acid, or tartaric acid as capping agent. The crystals, from nano- to microstructures with diverse shapes that include nanospheres, microrods, hexagonal prisms, microtubes, microdisks, polygonal columns, and hexagonal tablets, can be obtained with different reaction times, reaction temperatures, molar ratios of capping agent to sodium hydroxide, and by varying the binary acids. Fourier transform infrared, thermogravimetric analysis, and upconversion luminescence spectra measurements indicate that the synthesized NaYF(4):Yb/Er products with hydrophilic carboxyl-functionalized surface offer efficient upconversion luminescent performance. Furthermore, the antibody/secondary antibody conjugation can be realized by the carboxyl-functionalized surfaces of the upconversion phosphors, thus indicating the potential bioapplications of these kinds of materials.
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A single nucleotide polymorphism at the Vrn-D1 promoter region in common wheat is associated with vernalization response.
Theor. Appl. Genet.
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Facultative wheat varieties adapt to a particular environment. But the molecular basis for the facultative growth habit is not clear relative to winter and spring growth habit. Two sets of wheat varieties were chosen for this study. Set 1 comprised ten spring accessions and Set 2 comprised ten facultative accessions. All accessions had been tested by the previously described allele-specific markers and shown having the same allelic composition of vrn-A1 vrn-B1 Vrn-D1 and vrn-B3. Here we examined whether differences in growth habit might be associated with as yet unidentified sequence variation at Vrn-D1 locus. A region including the intron 1 deletion, the entire reading frame from a cDNA template and a part of promoter region of the dominant Vrn-D1 gene in each of the accessions was sequenced, and a single nucleotide polymorphism was found between facultative accessions and spring accessions in the CArG-box at the promoter region. The novel allele in facultative accessions was designated as Vrn-D1b. The investigation of an F(2) population segregating for Vrn-D1b and Vrn-D1a (previously, Vrn-D1) in the greenhouse under long days without vernalization showed that the plants with Vrn-D1b homozygous allele headed 32 days later and had about three more leaves than the plants with Vrn-D1a homozygous allele. As Vrn-D1b has the same deletion in intron 1 as Vrn-D1a, and, in addition, a single nucleotide mutation at promoter region, and is associated with facultative growth habit, we suggest that the promoter mutation may modify the basal activity level of an allele of VRN1 that is already active (due to the loss of segments in intron 1). Our finding further supports that both the promoter and intron 1 regulatory affect vernalization response and work independently.
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A versatile kinetics-controlled coating method to construct uniform porous TiO2 shells for multifunctional core-shell structures.
J. Am. Chem. Soc.
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The development of a simple and reproducible route to prepare uniform core@TiO(2) structures is urgent for realizing multifunctional responses and harnessing multiple interfaces for new or enhanced functionalities. Here, we report a versatile kinetics-controlled coating method to construct uniform porous TiO(2) shells for multifunctional core-shell structures. By simply controlling the kinetics of hydrolysis and condensation of tetrabutyl titanate (TBOT) in ethanol/ammonia mixtures, uniform porous TiO(2) shell core-shell structures can be prepared with variable diameter, geometry, and composition as a core (e.g., ?-Fe(2)O(3) ellipsoids, Fe(3)O(4) spheres, SiO(2) spheres, graphene oxide nanosheets, and carbon nanospheres). This method is very simple and reproducible, yet important, which allows an easy control over the thickness of TiO(2) shells from 0 to ~25, ~45, and ~70 nm. Moreover, the TiO(2) shells possess large mesoporosities and a uniform pore size of ~2.5 nm, and can be easily crystallized into anatase phase without changing the uniform core-shell structures.
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Murine CD4+ T cell responses are inhibited by cytotoxic T cell-mediated killing of dendritic cells and are restored by antigen transfer.
PLoS ONE
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Cytotoxic T lymphocytes (CTL) provide protection against pathogens and tumors. In addition, experiments in mouse models have shown that CTL can also kill antigen-presenting dendritic cells (DC), reducing their ability to activate primary and secondary CD8(+) T cell responses. In contrast, the effects of CTL-mediated killing on CD4(+) T cell responses have not been fully investigated. Here we use adoptive transfer of TCR transgenic T cells and DC immunization to show that specific CTL significantly inhibited CD4(+) T cell proliferation induced by DC loaded with peptide or low concentrations of protein antigen. In contrast, CTL had little effect on CD4(+) T cell proliferation induced by DC loaded with high protein concentrations or expressing antigen endogenously, even if these DC were efficiently killed and failed to accumulate in the lymph node (LN). Residual CD4(+) T cell proliferation was due to the transfer of antigen from carrier DC to host APC, and predominantly involved skin DC populations. Importantly, the proliferating CD4(+) T cells also developed into IFN-? producing memory cells, a property normally requiring direct presentation by activated DC. Thus, CTL-mediated DC killing can inhibit CD4(+) T cell proliferation, with the extent of inhibition being determined by the form and amount of antigen used to load DC. In the presence of high antigen concentrations, antigen transfer to host DC enables the generation of CD4(+) T cell responses regardless of DC killing, and suggests mechanisms whereby CD4(+) T cell responses can be amplified.
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Direct imaging the upconversion nanocrystal core/shell structure at the subnanometer level: shell thickness dependence in upconverting optical properties.
Nano Lett.
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Lanthanide-doped upconversion nanoparticles have shown considerable promise in solid-state lasers, three-dimensional flat-panel displays, and solar cells and especially biological labeling and imaging. It has been demonstrated extensively that the epitaxial coating of upconversion (UC) core crystals with a lattice-matched shell can passivate the core and enhance the overall upconversion emission intensity of the materials. However, there are few papers that report a precise link between the shell thickness of core/shell nanoparticles and their optical properties. This is mainly because rare earth fluoride upconversion core/shell structures have only been inferred from indirect measurements to date. Herein, a reproducible method to grow a hexagonal NaGdF(4) shell on NaYF(4):Yb,Er nanocrystals with monolayer control thickness is demonstrated for the first time. On the basis of the cryo-transmission electron microscopy, rigorous electron energy loss spectroscopy, and high-angle annular dark-field investigations on the core/shell structure under a low operation temperature (96 K), direct imaging the NaYF(4):Yb,Er@NaGdF(4) nanocrystal core/shell structure at the subnanometer level was realized for the first time. Furthermore, a strong linear link between the NaGdF(4) shell thickness and the optical response of the hexagonal NaYF(4):Yb,Er@NaGdF(4) core/shell nanocrystals has been established. During the epitaxial growth of the NaGdF(4) shell layer by layer, surface defects of the nanocrystals can be gradually passivated by the homogeneous shell deposition process, which results in the obvious enhancement in overall UC emission intensity and lifetime and is more resistant to quenching by water molecules.
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Development of a microplate reader compatible microfluidic chip for ELISA.
Biomed Microdevices
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We report a novel microfluidic device use for sandwich enzyme-linked immunoassay assay (ELISA). The related procedures including the introduction of reagents, dilution and distribution of samples, as well as immobilization of enzyme can be readily carried out on a poly (dimethylsiloxane) (PDMS) chip. Particularly, this microfluidic chip comprising of two distinct parallel units, and has an identical dimension as a conventional microtiter plate, which offers access to the directly quantitative detection by the microplate reader. Gradient-concentration reacting solutions at six different concentrations level generated by the microfluidic channel network are simultaneously transported to 24 reaction chambers to form enzymatic products. Alkaline phosphatase (ALP), 4-methylumbelliferyl phosphate (4-MUP) and KH(2)PO(4) are used as enzyme-substrate-inhibitor model, to demonstrate the utility of the developed microchip-based enzyme inhibitor assay. Various conditions such as the surface treatment of chip channels, fluids velocities, substrate concentration, and buffer pH are investigated. The present microfluidic device for ELISA holds several advantages, for instance frugal usage of samples and reagents, less of operating time, favorably integrated configuration, ease of manipulation, and could be explored to a variety of high throughput drug screening.
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Transcriptome analysis of stem development in the tumourous stem mustard Brassica juncea var. tumida Tsen et Lee by RNA sequencing.
BMC Plant Biol.
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Tumourous stem mustard (Brassica juncea var. tumida Tsen et Lee) is an economically and nutritionally important vegetable crop of the Cruciferae family that also provides the raw material for Fuling mustard. The genetics breeding, physiology, biochemistry and classification of mustards have been extensively studied, but little information is available on tumourous stem mustard at the molecular level. To gain greater insight into the molecular mechanisms underlying stem swelling in this vegetable and to provide additional information for molecular research and breeding, we sequenced the transcriptome of tumourous stem mustard at various stem developmental stages and compared it with that of a mutant variety lacking swollen stems.
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RhoE functions as a tumor suppressor in esophageal squamous cell carcinoma and modulates the PTEN/PI3K/Akt signaling pathway.
Tumour Biol.
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Emerging evidence indicates that RhoE as novel member of the Rho GTPases family plays an essential role in carcinogenesis and tumor progression of human various tumors, but the functional significance of RhoE in human esophageal squamous cell carcinoma (ESCC) is still unclear. In the current study, RhoE expression in ESCC tissues and cells was examined, and the biological functions of RhoE in ESCC cells were determined. The results revealed that RhoE expression at mRNA and protein levels was significantly downregulated in ESCC tissues and cell lines (P < 0.05). RhoE expression was tightly associated with differentiation degree, clinical staging, and lymph node metastasis of the patients with ESCC (P < 0.05), but no significant correlations were found between RhoE expression and gender or age of the patients with ESCC (P > 0.05). Additionally, we found that downregulation of RhoE expression in ESCC cells promoted cell proliferation, cell cycle progression, as well as cell invasion in vitro, and inhibited cell apoptosis. Conversely, upregulation of RhoE expression in ESCC cells inhibited cell proliferation, arrested cell cycle at G0/G1 phase, reduced cell invasion, and promoted cell apoptosis. Furthermore, the downregulation of RhoE expression significantly reduced PTEN level and enhanced pAkt level; however, elevation of RhoE expression markedly increased PTEN level and decreased pAkt level. Stepwise investigations demonstrated that overexpression of RhoE in ESCC cells increased the expressions of p27 and bax proteins but decreased the expressions of cyclin D1 and bcl-2 proteins. These data demonstrate that RhoE may play a driving role in the development and progression of ESCC, and targeting the RhoE may be an effective and feasible approach for treatment of ESCC.
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[An analytic method of wavelet energy value to evaluate the contraction intensity of uterus].
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi
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The data of uterine contraction pressure is the information source for extracting uterine contractions status. Because there is a variety of interference existing in contraction pressure data, commonly used methods such as uterine contraction intensity integration method can not obtain decent evaluation results. We used the bior 2.4 biorthogonal wavelet to decompose and reconstruct the pressure data in order to obtain the best denoising effect. Combining with the denoised results, we proposed an algorithm of the wavelet energy value. Based on the algorithm, we calculated the curve of wavelet energy value. It was proved that using the curve of wavelet energy value can better identify contractions waveform and evaluation contractions intensity.
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P2Y1 purinoceptor inhibition reduces extracellular signal-regulated protein kinase 1/2 phosphorylation in spinal cord and dorsal root ganglia: implications for cancer-induced bone pain.
Acta Biochim. Biophys. Sin. (Shanghai)
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It remains unclear as to whether P2Y1 purinergic receptor (P2Y1R) and the molecules that act downstream, such as extracellular signal-regulated protein kinase 1/2 (ERK1/2), are involved in the development of cancer-induced bone pain (CIBP) in vivo. Here, we investigated the role of the P2Y1R in the modulation of CIBP-associated nociception in spinal cord and dorsal root ganglia (DRG). A CIBP model was established by inoculating Walker 256 gland carcinoma cells into the tibia of female rats. Tactile allodynia and spontaneous pain were assessed using von Frey filaments and ambulatory scores. The results showed that both the paw withdrawal latency to tactile allodynia and the ambulatory score to spontaneous pain were significantly different between the CIBP group and the sham group on days 7-9 post-inoculation (P< 0.01). Furthermore, rats in the CIBP group also showed a progressive increase in ambulatory score, which is different from the sham group (P< 0.01). Furthermore, P2Y1R mRNA and phosphorylated ERK1/2 (p-ERK1/2) protein expression levels were increased in the spinal dorsal horn and DRG of the CIBP group relative to the sham group. However, intrathecal injection of the P2Y1R antagonist MRS2179 decreased P2Y1R mRNA and p-ERK1/2 protein expression in the spinal dorsal horn and DRG (P< 0.01). These results provide evidence that the inhibition of P2Y1R-mediated ERK1/2 phosphorylation in the spinal dorsal horn and DRG can attenuate nociception transmission.
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Allergen-specific CTL require perforin expression to suppress allergic airway inflammation.
J. Immunol.
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Allergen-specific CTL have a protective effect on allergic airway inflammation, a function thought to be mediated by cytokines, especially IFN-?. However, the contribution of cytotoxic function to this protective effect has not been investigated. We examined the contribution of cytotoxic function to the therapeutic effect of allergen-specific CTL in allergic airway inflammation. We used a murine model of allergic airway inflammation in which mice were sensitized to OVA and then challenged with the same Ag via the intranasal route. CTL were elicited in these mice by immunization with dendritic cells (DC) or by adoptive transfer of in vitro-activated CD8(+) T cells. Hallmark features of allergic asthma, such as infiltration of eosinophils in the bronchoalveolar lavage fluid and mucus production, were assessed. Suppression of allergic airway inflammation by allergen-specific CTL was critically dependent on the expression of perforin, a key component of the cytotoxic machinery. Both perforin-sufficient and perforin-deficient allergen-specific CTL were recovered from the lungs of allergen-sensitized mice and upregulated CD69 expression and secreted the cytokines IFN-? and TNF-? upon intranasal allergen challenge. However, only perforin-sufficient CTL inhibited eosinophil infiltration in the airway, mucus production, and cytokine accumulation in the bronchoalveolar lavage fluid. Treatment with allergen-specific CTL, but not their perforin-deficient counterparts, was also associated with a decrease in the number of DC in the mediastinal lymph node. Our data suggest that the cytotoxic function of allergen-specific CD8(+) T cells is critical to their ability to moderate allergic airway inflammation.
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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.