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Find video protocols related to scientific articles indexed in Pubmed.
The room temperature electrochemical synthesis of N-doped graphene and its electrocatalytic activity for oxygen reduction.
Chem. Commun. (Camb.)
PUBLISHED: 11-06-2014
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We report a facile and green electrochemical method using graphene oxide as the precursor to synthesize nitrogen doped graphene at room temperature in ammonia containing aqueous solution. The nitrogen doping content reaches 3.3 at%, and the resultant NG shows excellent activity toward the oxygen reduction reaction.
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Rapid diversification of five Oryza AA genomes associated with rice adaptation.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 11-03-2014
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Comparative genomic analyses among closely related species can greatly enhance our understanding of plant gene and genome evolution. We report de novo-assembled AA-genome sequences for Oryza nivara, Oryza glaberrima, Oryza barthii, Oryza glumaepatula, and Oryza meridionalis. Our analyses reveal massive levels of genomic structural variation, including segmental duplication and rapid gene family turnover, with particularly high instability in defense-related genes. We show, on a genomic scale, how lineage-specific expansion or contraction of gene families has led to their morphological and reproductive diversification, thus enlightening the evolutionary process of speciation and adaptation. Despite strong purifying selective pressures on most Oryza genes, we documented a large number of positively selected genes, especially those genes involved in flower development, reproduction, and resistance-related processes. These diversifying genes are expected to have played key roles in adaptations to their ecological niches in Asia, South America, Africa and Australia. Extensive variation in noncoding RNA gene numbers, function enrichment, and rates of sequence divergence might also help account for the different genetic adaptations of these rice species. Collectively, these resources provide new opportunities for evolutionary genomics, numerous insights into recent speciation, a valuable database of functional variation for crop improvement, and tools for efficient conservation of wild rice germplasm.
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[Effects of shade on photosynthetic characteristics and chlorophyll fluorescence of Ardisia violacea].
Ying Yong Sheng Tai Xue Bao
PUBLISHED: 10-28-2014
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Ardisia violacea is one of the rare and endangered species, and distributes only in Zhejiang and Taiwan Provinces in China. In order to understand the light requirement and adaptability of A. violacea, the effects of different light intensities (shading rate of 90%, 60%, 25%, and the full light) on leaf photosynthetic characteristics and chlorophyll fluorescence of A. violacea were studied. The photosynthetic rate (Pn) and stomatal conductance (g(s)) of A. violacea varied as a bimodal curve with a 'midday depression' phenomenon in full bright light, and as a unimodal curve in the shading treatments. With the increasing shading rate, the Pn and apparent quantum efficiency (AQY) first increased, and then decreased, the light compensation point (LCP) and light saturation point (LSP) decreased, and the g(s), transpiration rate (Tr), original light energy conversion (Fv/Fm) and potential activity of PS II (Fv/Fo) increased. The total quantity of chlorophyll and the carotenoid (Car) content increased, and Chl a/b decreased under shading conditions. When the shading rate was 25%, the specific leaf mass (LMA) and root to shoot (R/T) ratio of A. violacea reached the maximum. A. violacea possessed a strong flexibility to different light environments, suggesting that light could not be the main limiting factor for natural regeneration of A. violacea populations.
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Citrate-capped platinum nanoparticle as a smart probe for ultrasensitive mercury sensing.
Anal. Chem.
PUBLISHED: 10-27-2014
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An easily prepared platinum nanoparticle (PtNP) probe for the sensitive and selective detection of Hg(2+) ions is developed here. The PtNPs with an average size of approximately 2.5 nm were prepared by a reduction method with sodium borohydride and trisodium citrate serving as reductant and stabilizer, respectively. The resulting PtNPs could catalyze the reduction of Hg(2+) by surface-capping citrate. The effect of Hg(2+) uptake implies amalgam formation, which leads to remarkable inhibition of the peroxidase-like activity of citrate-capped PtNPs. On the basis of this effect, a colorimetric mercury sensor was established through the use of citrate-capped PtNPs to catalyze the colorimetric system of 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2. The high specificity of the Hg-Pt interaction provides the excellent selectivity for Hg(2+) over interfering metal ions. The sensitivity of this smart probe to Hg(2+) is extremely excellent with a limit of detection (LOD) as low as 8.5 pM. In view of these advantages, as well as the cost-effectiveness, minimized working steps, and naked-eye observation, we expect that this colorimetric sensor will be a promising candidate for the field detection of toxic Hg(2+) ions in environmental, biological, and food samples.
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Ultrafast waveform synthesis and characterization using coherent Raman sidebands in a reflection scheme.
Opt Express
PUBLISHED: 10-17-2014
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Coherent Raman sidebands have the potential to serve as a source of single cycle pulses. We generate these sidebands by crossing two-color femtosecond laser pulses in a Raman-active crystal. We design a reflection scheme using spherical mirrors to combine coherent Raman sidebands. The sidebands and the driving pulses are refocused back to the Raman crystal and the relative spectral phases are retrieved from an interferogram based on the nonlinear Raman interaction. Furthermore, using a deformable mirror to adjust the spectral phases, we demonstrate that our setup is capable of synthesizing ultrafast waveforms using coherent Raman sidebands.
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Floating Growth of Large-Scale Freestanding TiO2 Nanorod Films at the Gas-Liquid Interface for Additive-Free Li-Ion Battery Applications.
ACS Appl Mater Interfaces
PUBLISHED: 10-03-2014
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The floating growth process of large-scale freestanding TiO2 nanorod films at the gas-liquid interface was investigated. On the basis of the experiments, a self-templated growth scenario was developed to account for the self-assembly process. In the scenario, titanium complexes function not only as the Ti source for the growth of TiO2 but also as a soft template provider for the floating growth. According to the scenario, several new recipes of preparing freestanding TiO2 nanorod films at the gas-liquid interface were developed. The freestanding film was applied to a lithium ion battery as a binder-free and conducting agent-free anode, and good cyclability was obtained. This work may pave a new way to floating and freestanding TiO2 and other semiconductor materials, which has great potential not only in basic science but also in the applications such as materials engineering, Li-ion battery, photocatalyst, dye-sensitized solar cell, and flexible electronics.
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Effects of l-Carnitine, Erythritol and Betaine on Pro-inflammatory Markers in Primary Human Corneal Epithelial Cells Exposed to Hyperosmotic Stress.
Curr. Eye Res.
PUBLISHED: 10-02-2014
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Abstract Purpose: To explore the effects of osmoprotectants on pro-inflammatory mediator production in primary human corneal epithelial cells (HCECs) exposed to hyperosmotic stress. Methods: HCECs cultured in iso-osmolar medium (312 mOsM) were switched to hyperosmotic media with or without prior incubation with 2-20?mM of l-carnitine, erythritol or betaine for different time periods. The mRNA expression and protein production of pro-inflammatory markers in HCECs were evaluated by RT-qPCR and ELISA. Results: Hyperosmolar media significantly stimulated the mRNA and protein expression of pro-inflammatory cytokines, TNF-?, IL-1? and IL-6, and chemokines, IL-8, CCL2 and CCL20 in HCECs in an osmolarity dependent manner. The stimulated expression of these pro-inflammatory mediators was significantly but differentially suppressed by l-carnitine, erythritol or betaine. l-Carnitine displayed the greatest inhibitory effects and down-regulated 54-77% of the stimulated mRNA levels of TNF-? (down from 12.3-5.7 fold), IL-1? (2.2-0.9 fold), IL-6 (7.3-2.9 fold), IL-8 (4.6-2.0 fold), CCL2 (15.3-3.5 fold) and CCL20 (4.1-1.5 fold) in HCECs exposed to 450 mOsM. The stimulated protein production of TNF-?, IL-1?, IL-6 and IL-8 was also significantly suppressed by l-carnitine, erythritol and betaine. l-carnitine suppressed 49-79% of the stimulated protein levels of TNF-? (down from 81.3 to 17.4?pg/ml), IL-1? (56.9-29.2?pg/ml), IL-6 (12.8-4.6?ng/ml) and IL-8 (21.2-10.9?ng/ml) by HCECs exposed to 450 mOsM. Interestingly, hyperosmolarity stimulated increase in mRNA and protein levels of TNF-?, IL-1? and IL-6 were significantly suppressed by a transient receptor potential vanilloid channel type 1 (TRPV1) activation inhibitor capsazepine. Conclusions: l-carnitine, erythritol and betaine function as osmoprotectants to suppress inflammatory responses via TRPV1 pathway in HCECs exposed to hyperosmotic stress. Osmoprotectants may have efficacy in reducing innate inflammation in dry eye disease.
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Comparison of three transgenic Bt rice lines for insecticidal protein expression and resistance against a target pest, Chilo suppressalis (Lepidoptera: Crambidae).
Insect Sci.
PUBLISHED: 09-25-2014
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Two transgenic rice lines (T2A-1 and T1C-19b) expressing cry2A and cry1C genes, respectively, were developed in China, targeting lepidopteran pests including Chilo suppressalis (Walker) (Lepidoptera: Crambidae). The seasonal expression of Cry proteins in different tissues of the rice lines and their resistance to C. suppressalis were assessed in comparison to a Bt rice line expressing a cry1Ab/Ac fusion gene, Huahui 1, which has been granted a biosafety certificate. In general, levels of Cry proteins were T2A-1 > Huahui 1 >T1C-19b among rice lines, and leaf > stem > root among rice tissues. The expression patterns of Cry protein in the rice line plants were similar: higher level at early stages than at later stages with an exception that high Cry1C level in T1C-19b stems at the maturing stage. The bioassay results revealed that the three transgenic rice lines exhibited significantly high resistance against C. suppressalis larvae throughout the rice growing season. According to Cry protein levels in rice tissues, the raw and corrected mortalities of C. suppressalis caused by each Bt rice line were the highest in the seedling and declined through the jointing stage with an exception for T1C-19b providing an excellent performance at the maturing stage. By comparison, T1C-19b exhibited more stable and greater resistance to C. suppressalis larvae than T2A-1, being close to Huahui 1. The results suggest cry1C is an ideal Bt gene for plant transformation for lepidopteran pest control, and T1C-19b is a promising Bt rice line for commercial use for tolerating lepidopteran rice pests. This article is protected by copyright. All rights reserved.
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Organohalide lead perovskite based photodetectors with much enhanced performance.
Chem. Commun. (Camb.)
PUBLISHED: 09-24-2014
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CH3NH3PbI3 based photodetectors were fabricated by a facile low-cost process with much enhanced performance. The rise time changed from 2.7 s to 0.02 s, the decay time from 0.5 s to 0.02 s, and the ON/OFF ratio tripled with improved stability. The results indicate that perovskites are promising light-harvesting materials for photodetectors.
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[Analysis of the phase of left ventricular isovolumic relaxation time in healthy people using dual-channel echocardiography].
Zhongguo Ying Yong Sheng Li Xue Za Zhi
PUBLISHED: 09-24-2014
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To exacted analysis each time interval in isovolumic relaxation time (IVRT) of normal subjects through observin the changes of cardiac structure and hemodynamics during the IVRT. Then to provide the evidence of cardiac resynchronization therapy.
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Transcriptome analysis of the oil-rich tea plant, Camellia oleifera, reveals candidate genes related to lipid metabolism.
PLoS ONE
PUBLISHED: 08-19-2014
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Rapidly driven by the need for developing sustainable sources of nutritionally important fatty acids and the rising concerns about environmental impacts after using fossil oil, oil-plants have received increasing awareness nowadays. As an important oil-rich plant in China, Camellia oleifera has played a vital role in providing nutritional applications, biofuel productions and chemical feedstocks. However, the lack of C. oleifera genome sequences and little genetic information have largely hampered the urgent needs for efficient utilization of the abundant germplasms towards modern breeding efforts of this woody oil-plant.
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Donnan potential caused by polyelectrolyte monolayers.
Langmuir
PUBLISHED: 08-14-2014
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The Donnan potential is successfully isolated from ion pair potential on a ferrocene-labeled polyelectrolyte (DNA) monolayer. The isolated Donnan potential shifts negatively upon the increase in NaClO4 concentration with a slope of -58.8 mV/decade. With the salt concentration grown up to 1 M, the stretched DNA chains in low salt concentration are found to experience a gradual conformation relaxing process. At salt concentrations higher than 2 M, Donnan breakdown occurs where only the ion pair effect modulates the apparent potential. The apparent formal potential also shows strong dependence on solution pH, which reveals that the charge density in the polyelectrolyte monolayer plays an important role in the establishment of Donnan equilibrium.
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In situ synthesis of uniform Fe2O3/BiOCl p/n heterojunctions and improved photodegradation properties for mixture dyes.
Dalton Trans
PUBLISHED: 08-09-2014
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The xFe2O3/yBiOCl composites (xFe/yBi, x/y = 0/100, 5/100, 10/100, 20/100, 30/100 and 40/100 molar ratios) are prepared for the first time through an in situ hydrolysis method under hydrothermal conditions. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and UV-visible diffuse reflectance spectroscopy (UV-DRS). The photodegradation performances of the xFe/yBi samples are investigated using a simulated industrial wastewater mixture containing both rhodamine B (RhB) and methyl orange (MO). The uniform Fe2O3 nanocubes are found to be well distributed on the BiOCl nanosheets. Moreover, the xFe/yBi photocatalysts exhibit unexpectedly higher efficiencies than bare BiOCl or Fe2O3 under ultraviolet light irradiation (? ? 420 nm). Specifically, the degradation rates of the xFe/yBi samples at x/y = 5/100 and 10/100 are four times higher than that of bare BiOCl for MO-RhB mixed dye solutions. Their high photocatalytic activities are mainly attributed to the formation of stable p/n heterojunctions between Fe2O3 and BiOCl, which greatly improve the separation of photogenerated carriers. Importantly, the highly efficient and inexpensive xFe/yBi p/n heterojunctions are expected to be useful in practical industrial wastewater applications involving complicated toxic components.
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A green approach to the synthesis of novel "Desert rose stone"-like nanobiocatalytic system with excellent enzyme activity and stability.
Sci Rep
PUBLISHED: 08-01-2014
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3D hierarchical layer double hydroxides (LDHs) have attracted extensive interest due to their unique electronic and catalytic properties. Unfortunately, the existing preparation methods require high temperature or toxic organic compounds, which limits the applications of the 3D hierarchical LDHs in biocatalysis and biomedicine. Herein, we present a green strategy to synthesize "Desert Rose Stone"-like Mg-Al-CO3 LDH nanoflowers in situ deposited on aluminum substrates via a coprecipitation method using atmospheric carbon dioxide. Using this method, we construct a novel "Desert Rose Stone"-like nanobiocatalytic system by using HRP as the model enzyme. Compared with the free HRP, the HRP/Mg-Al-LDH nanobiocatalytic system exhibits higher catalytic activity and stability. A smaller apparent Michaelis-Menten constant (0.16?mM) of this system suggests that the encapsulated HRP shows higher affinity towards H2O2.
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Remote control of reversible localized protein adsorption in microfluidic devices.
ACS Appl Mater Interfaces
PUBLISHED: 07-31-2014
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We present a facilely prepared graphene oxide (GO)/ poly(dimethylsiloxane) (PDMS) composite by dispersing nanosized GO in PDMS. On the basis of the combination of photothermal effects of GO and grafted thermoresponsive polymer, poly(N-isopropylacrylamide) (PNIPAAm), an optical-driving approach for remote control of localized wettability is realized. And this method has been successfully applied in the spatially controlled reversible protein adsorption in microfluidic devices.
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Highly efficient degradation of dye pollutants by Ce-doped MoO? catalyst at room temperature.
Dalton Trans
PUBLISHED: 07-15-2014
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In order to efficiently degrade organic pollutants via an easily operated method, Ce-doped MoO3 (Ce(x)/MoO3) samples are synthesized by a simple impregnation method. The samples are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), nitrogen sorption isotherms and UV-vis diffused reflectance spectra (UV-DRS), total organic carbon (TOC), infrared spectroscopy (IR) and mass spectrometry (MS) analyses. Furthermore, we have mainly investigated the degradation of different dye pollutants by the Ce(x)/MoO3 samples, including cationic methylene blue (MB), anionic methyl orange (MO), neutral phenol, and a MB-MO mixture dye. For the single-component MB and MO dyes, the highest degradation efficiencies are achieved by Ce(5)/MoO3 and Ce(10)/MoO3 samples. For the MB-MO mixture dyes, the highest degradation efficiency for MB is achieved by a Ce(10)/MoO3 sample. It is surprising that the degradation efficiency of MB in the MB-MO mixture dye solution is higher than that in the single-component MB dye solution, which has been mainly ascribed to the promoting effect of MO. Moreover, a plausible degradation mechanism of the dyes has been proposed and discussed. It should be noted that the degradation reaction is carried out at room temperature and normal atmospheric pressure, and without light irradiation. As a result, this degradation reaction is obviously different from the conventional thermally activated heterogeneous catalysis (or photocatalysis), in which thermal energy (or light irradiation) is indispensable; also different from a sorption technology, in which the pollutants cannot be degraded, but only transformed from one phase to another one. Thus, the reported degradation reaction is a quite promising environmental cleaning technology, which could be widely practically applied.
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Bioinspired copper catalyst effective for both reduction and evolution of oxygen.
Nat Commun
PUBLISHED: 06-17-2014
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In many green electrochemical energy devices, the conversion between oxygen and water suffers from high potential loss due to the difficulty in decreasing activation energy. Overcoming this issue requires full understanding of global reactions and development of strategies in efficient catalyst design. Here we report an active copper nanocomposite, inspired by natural coordination environments of catalytic sites in an enzyme, which catalyzes oxygen reduction/evolution at potentials closely approaching standard potential. Such performances are related to the imperfect coordination configuration of the copper(II) active site whose electron density is tuned by neighbouring copper(0) and nitrogen ligands incorporated in graphene. The electron transfer number of oxygen reduction is estimated by monitoring the redox of hydrogen peroxide, which is determined by the overpotential and electrolyte pH. An in situ fluorescence spectroelectrochemistry reveals that hydroxyl radical is the common intermediate for the electrochemical conversion between oxygen and water.
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Coherent broadband light generation with a double-path configuration.
Appl Opt
PUBLISHED: 06-13-2014
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We generate broadband light by focusing two femtosecond pulses into a Raman-active crystal. By reflecting Raman sideband beams together with the two driving beams back to the same crystal (with a slight spatial offset), we generate sidebands covering a broader spectral range, compared to a single pass. In this novel double-path configuration, multiple Raman sideband beams interact with each other since the phase-matching condition is automatically fulfilled. This scheme enables an enhanced cascaded coherent anti-Stokes scattering process and also doubles the interaction length, thus it allows one to use relatively weak energy pump pulses and thereby avoid optical damage.
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Distance-determined sensitivity in attenuated total reflection-surface enhanced infrared absorption spectroscopy: aptamer-antigen compared to antibody-antigen.
Chem. Commun. (Camb.)
PUBLISHED: 06-06-2014
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Distance-dependent signal intensity in immunoassay by attenuated total reflection-surface enhanced infrared absorption spectroscopy is demonstrated by controlling the distance of target proteins away from the enhancement substrate. Based on this optical near-field effect, sensitive detection of protein molecules with a detection limit of 0.6 nM and investigation of the kinetics and thermodynamics of protein-aptamer/antibody interactions can be achieved.
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A rapid and sensitive method for hydroxyl radical detection on a microfluidic chip using an N-doped porous carbon nanofiber modified pencil graphite electrode.
Analyst
PUBLISHED: 05-20-2014
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Hydroxyl radicals (?OH) play an important role in human diseases. Traditional detection methods are time consuming and require expensive instruments. Here, we present a simple and sensitive method for the detection of hydroxyl radicals on a microfluidic chip using an electrochemical technique. Aniline monomer is electrochemically polymerized on the surface of a pencil graphite electrode and carbonized at 800 °C. The resulting N-doped porous carbon nanofiber-modified pencil graphite electrode is embedded into a microfluidic chip directly as a working electrode. 4-Hydroxybenzoic acid (4-HBA) is selected as the trapping agent owing to its unique 3,4-DHBA product and high trapping efficiency. A low detection limit of 1.0 × 10(-6) M is achieved on the microfluidic chip. As a demonstration, the microfluidic chip is successfully utilized for the detection of ?OH in cigarette smoke. The strong ?-? stacking and hydrophobic interactions between the nitrogen-doped carbon materials and the pencil graphite make the modified electrode well-suited for the microfluidic chip.
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Choline and acetylcholine detection based on peroxidase-like activity and protein antifouling property of platinum nanoparticles in bovine serum albumin scaffold.
Biosens Bioelectron
PUBLISHED: 05-16-2014
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Platinum nanoparticles (PtNPs) in the scaffold of bovine serum albumin (BSA) through biomineralization are found to possess excellent peroxidase-like activity that can catalyze N-ethyl-N-(3-sulfopropyl)-3-methylaniline sodium salt (TOPS) coupled with 4-amino-antipyrine (4-AAP) by the action of hydrogen peroxide to give an obvious purple product. Based on this phenomenon, acetylcholinesterase (AChE) and choline oxidase (ChOx) are used to catalyze ACh and choline to form the active product H2O2 and the as-produced H2O2 is detected optically. Owning to the protection effect of the protein shell, BSA-PtNPs turn out to be very stable and preserve the catalytic activity in the presence of protein and even in the real plasma samples. This protein antifouling property makes the BSA-PtNPs suitable for a wide range of applications in sensors for biological samples. Choline in infant formula and ACh in plasma have been successfully detected.
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Flight-crash events in turbulence.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 05-02-2014
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The statistical properties of turbulence differ in an essential way from those of systems in or near thermal equilibrium because of the flux of energy between vastly different scales at which energy is supplied and at which it is dissipated. We elucidate this difference by studying experimentally and numerically the fluctuations of the energy of a small fluid particle moving in a turbulent fluid. We demonstrate how the fundamental property of detailed balance is broken, so that the probabilities of forward and backward transitions are not equal for turbulence. In physical terms, we found that in a large set of flow configurations, fluid elements decelerate faster than accelerate, a feature known all too well from driving in dense traffic. The statistical signature of rare "flight-crash" events, associated with fast particle deceleration, provides a way to quantify irreversibility in a turbulent flow. Namely, we find that the third moment of the power fluctuations along a trajectory, nondimensionalized by the energy flux, displays a remarkable power law as a function of the Reynolds number, both in two and in three spatial dimensions. This establishes a relation between the irreversibility of the system and the range of active scales. We speculate that the breakdown of the detailed balance characterized here is a general feature of other systems very far from equilibrium, displaying a wide range of spatial scales.
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Conformational change and biocatalysis-triggered spectral shift of single Au nanoparticles.
Chem. Commun. (Camb.)
PUBLISHED: 04-11-2014
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Spectral shift of localized plasmon resonance scattering of guanine-rich DNA modified single Au nanoparticles is observed under a dark field microscope equipped with a spectrometer. The spectra continuously red-shift with the conformational change of the guanine-rich DNA upon associating with K(+), hemin and the biocatalytic growth of the polymer. The scattering spectrum of single nanoparticles is proved to be sensitive both to a subtle conformational change and the biocatalysis process. 20 mM K(+) or 100 ?M H2O2 can trigger a detectable peak shift. The present study paves a new and efficient way to extract chemical information from micro/nanospace.
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[Research on the patterns of upper airway obstructive levels by drug-induced sleep endoscopy].
Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi
PUBLISHED: 04-01-2014
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To identify the patterns of airway collapse in patients with obstructive sleep apnea hypopnea syndrome(OSAHS) by dexmedetomidine induced sleep endoscopy.
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Overexpression of RUNX3 inhibits malignant behaviour of Eca109 cells in vitro and vivo.
Asian Pac. J. Cancer Prev.
PUBLISHED: 03-20-2014
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Runt-related transcription factor 3 (RUNX3) is a tumor suppressor gene whose reduced expression may play an important role in the development and progression of esophageal squamous cell cancer (ESCC). The aim of this study was to investigate the clinical relevance of RUNX3 in ESCC patients and effects of overexpression on biological behaviour of Eca109 cells in vitro and in vivo. Immunohistochemistry was performed to detect the clinical relevance of RUNX3 and lymph node metastasis in 80 ESCC tissues and 40 non-cancerous tissues using the SP method. RT-PCR and Western blotting were applied to assess the RUNX3 level and verify the Eca109 cell line with stable overexpression. Localization of RUNX3 proteins was performed by cell immunofluorescence. CCK-8 and Scrape motility assays were used to determine proliferation and migration and the TUNEL assay to analyze cell apoptosis. Invasive potential was assessed in cell transwell invasion experiments. In nude mice, tumorigenesis in vivo was determined. Results showed decreased expression of RUNX3 in esophageal tissue to be significantly related to lymph node metastasis (LNM) (P<0.01). In addition, construction of a recombinant lentiviral vector and transfection into the human ESCC cell line Eca109 demonstrated that overexpression could inhibit cell proliferation, migration and invasion, and induce apoptosis. The in vivo experiments in mice showed tumorigenicity and invasiveness to be significantly reduced. Taken together, our studies indicate that underexpression of RUNX3 in human ESCC tissue is significantly correlated with progression. Restoration of RUNX3 expression significantly inhibits ESCC cells proliferation, migration, invasion and tumorigenesis.
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Human corneal epithelial cells produce antimicrobial peptides LL-37 and ?-defensins in response to heat-killed Candida albicans.
Ophthalmic Res.
PUBLISHED: 03-18-2014
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To explore the innate response of human corneal epithelial cells (HCECs) exposed to fungus by producing antimicrobial peptides LL-37 and ?-defensins.
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Sensitive assay of protease activity on a micro/nanofluidics preconcentrator fused with the fluorescence resonance energy transfer detection technique.
Anal. Chem.
PUBLISHED: 03-10-2014
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A fast and sensitive assay of protease activity on a micro/nanofluidics preconcentrator combining with fluorescence resonance energy transfer (FRET) detection technique has been developed in a homogeneous real-time format. First, the functionalized nanoprobes are formed by loading dye labeled protein onto gold nanoparticles (AuNPs), in which, the photoluminescence of donor dye was strongly quenched by AuNPs due to FRET mechanisms. For protease activity assay, the nanoprobes are enriched by a micro/nanofluidics preconcentrator. When the target protease is transported to the enriched nanoprobes, cleavage of protein occurs as a consequence of molecular recognition of enzyme to substrate. The release of cleavage fragments from AuNPs nanoprobes leads to the enhancement of fluorescence and enables the protease activity assay on the micro/nanofluidics chip. As a demonstration, digestion of fluorescein isothiocyanate labeled dog serum albumin (FITC-DSA) by trypsin was used as a model reaction. Because of the highly efficient preconcentration and space confinement effect, significantly increased protein cleavage rate and protease assay sensitivity can be achieved with enhanced enzyme activity. The present micro/nanofluidics platform fused with the FRET detection technique is promising for fast and sensitive bioanalysis such as immunoassay, DNA hybridization, drug discovery, and clinical diagnosis.
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Core-shell Ag@SiO(2) nanoparticles concentrated on a micro/nanofluidic device for surface plasmon resonance-enhanced fluorescent detection of highly reactive oxygen species.
Anal. Chem.
PUBLISHED: 03-04-2014
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A micro/nanofluidic device integrating a nanochannel in a microfluidic chip was developed for sensitive fluorescent determination of highly reactive oxygen species (hROS) enhanced by surface plasmon resonance-enhanced fluorescence (SPREF). The nanochannel was simply fabricated by polyaniline nanostructures modified on a glass slide. Core-shell Ag@SiO2 nanoparticles were concentrated in front of the nanochannel for fluorescence enhancement based on the SPREF effect. As a demonstration, hROS in the mainstream of cigarette smoke (CS) were detected by the present micro/nanofluidic device. The fluorescent probe for trapping hROS in puffs of CS employed a microcolumn that was loaded with a composite of DNA (conjugated fluorophores, FAM) and Au membrane (coated on cellulose acetate). With a laser-induced fluorescence detection device, hROS was determined on the basis of the amount of FAM groups generated by DNA cleavage. With the optimization of the trapping efficiency, we detected about 4.91 pmol of hROS/puff in the mainstream CS. This micro/nanofluidic-SPREF system promises a simple, rapid, and highly sensitive approach for determination of hROS in CS and other practical systems.
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Ice crystals growth driving assembly of porous nitrogen-doped graphene for catalyzing oxygen reduction probed by in situ fluorescence electrochemistry.
Sci Rep
PUBLISHED: 02-28-2014
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In recent years, doped carbonaceous materials as alternative catalysts for oxygen reduction reaction (ORR) have received considerable attention due to the low cost and high CO tolerance capability. Different theoretical studies have suggested that oxygen is reduced in a rapid sequence intermediated by diverse oxygen-containing reactive intermediates (ORI). However, due to the short lifetimes of the possible ORI, direct experimental evidence is very difficult to be obtained. Here, we report the synthesis of an ultralight and porous nitrogen-doped graphene (NG) by annealing graphite oxide (GO)-melamine scaffold shaped in ice template. The resultant NG exhibits excellent electrocatalytic activity toward 4e-reduction of oxygen with the onset potential as low as -0.05?V vs. Ag/AgCl in alkaline media. Using this material as model study, sensitive in situ fluorescence spectroelectrochemistry is applied to demonstrate the presence the reactive ORI. The global ORR pathway is unraveled as stepwise electron transfer involving hydroxyl radical as the important intermediate via both inner- and outer-sphere process. This result would likely provide a new insight into the further understanding of ORR mechanism on those intrinsic carbonaceous materials.
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Ophthalmic viscosurgical device-assisted sutureless-incision cataract surgery for a hard nucleus or mature cataract.
J Cataract Refract Surg
PUBLISHED: 02-26-2014
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We describe a modified method of sutureless-incision cataract surgery using an ophthalmic viscosurgical device (OVD) to extract a hard lenticular nucleus or mature cataract. After an isosceles trapezoid-shaped sclerocorneal tunnel and a round 7.0 mm diameter capsulorhexis are made, the nucleus is displaced into the anterior chamber. As OVD is injected, the OVD cannula acts as a slide to guide the nucleus out of the eye. Ophthalmic viscosurgical device-assisted sutureless-incision cataract surgery was used in a consecutive series of 182 eyes with a hard nucleus (57 eyes), mature cataract (47 eyes), or both (78 eyes). No posterior capsule rupture or vitreous loss occurred during surgery and no wound leakage or hypotony occurred postoperatively. The uncorrected visual acuity improved to 20/60 or better in 122 eyes (67%) on the first postoperative day. Ophthalmic viscosurgical device-assisted sutureless-incision cataract surgery, usually without additional instruments or sutures, offers an effective and uncomplicated technique for managing a brunescent or mature cataract.
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Neuroprotective effect of a formula, moschus combined with borneolum synthcticum, from traditional chinese medicine on ischemia stroke in rats.
Evid Based Complement Alternat Med
PUBLISHED: 02-22-2014
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Moschus compatible with borneolum synthcticum is a well-known herb pair in Traditional Chinese Medicine and the present study aims to assess the neuroprotective effect of a formula composed of this herb pair on ischemia stroke in rats. The middle cerebral artery occlusion model of focal cerebral ischemia in rat was performed by using intraluminal suture method. The behavioral scores, infarct volume, and neuron ultrastructure of model and formula-treated rats were investigated after the 2?h of ischemia and 24?h of reperfusion. Meanwhile the expression levels of caspase-3, caspase-9, Bcl-2, and Bax were measured by western blot analysis. The formula treatment showed obvious neuroprotective effect according to significant decrease of the neurological scores (P < 0.01) and the infarct volumes (P < 0.05) when compared to the MCAO group. We also observed that this formula had antiapoptosis activity on neuron cell under electron microscope. Furthermore, our result supported the idea that pro- and postadministration of this formula had an antiapoptosis effect by decreasing remarkably the expression of caspase-3 and caspase-9 (P < 0.05) as well as increasing significantly the ratio of Bcl-2 to Bax (P < 0.01). All evidences demonstrated the neuroprotective effect of this formula on ischemia stroke due to decrease of brain infract volume and modulation of the expression of apoptosis-related proteins.
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In situ growth of porous platinum nanoparticles on graphene oxide for colorimetric detection of cancer cells.
Anal. Chem.
PUBLISHED: 02-20-2014
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A green approach is proposed for in situ growth of porous platinum nanoparticles on graphene oxide (PtNPs/GO). The resulting nanocomposite has been proven to function as peroxidase mimetics that can catalyze the reaction of peroxidase substrate in the presence of hydrogen peroxide. On the basis of the peroxidase-like activity, we used the PtNPs/GO as a signal transducer to develop a colorimetric assay for the direct detection of cancer cells. By using folic acid as a recognition element, a total of 125 cancer cells (MCF-7) can be distinguished by naked-eye observation. We envision that this nanomaterial could be used as a power tool for a wide range of potential applications in biotechnology and medicine.
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Fluorescent hydrogen peroxide sensor based on cupric oxide nanoparticles and its application for glucose and L-lactate detection.
Biosens Bioelectron
PUBLISHED: 02-18-2014
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A novel fluorescent hydrogen peroxide sensor was developed based on the peroxidase-like activity of cupric oxide nanoparticles. Cupric oxide nanoparticles effectively catalyzed the decomposition of hydrogen peroxide into hydroxyl radicals. Then terephthalic acid was oxidized by hydroxyl radical to form a highly fluorescent product. The linear range of hydrogen peroxide estimated to be 5.0 × 10(-6)-2.0 × 10(-4)M with a detection limit of 3.4 × 10(-7)M. Moreover, this detection system enabled the sensing of analytes which can enzymatically generate hydrogen peroxide. By coupling the oxidation of glucose or L-lactate catalyzed by their corresponding oxidase enzymes with terephthalic acid oxidation catalyzed by cupric oxide nanoparticles, sensitive assays of glucose and l-lactate with detection limits of 1.0 × 10(-6) and 4.5 × 10(-8)M were realized. The successful applications of this approach in human serum samples have also been demonstrated.
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Pyramiding expression of maize genes encoding phosphoenolpyruvate carboxylase (PEPC) and pyruvate orthophosphate dikinase (PPDK) synergistically improve the photosynthetic characteristics of transgenic wheat.
Protoplasma
PUBLISHED: 02-10-2014
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Using particle bombardment transformation, we introduced maize pepc cDNA encoding phosphoenolpyruvate carboxylase (PEPC) and ppdk cDNA encoding pyruvate orthophosphate dikinase (PPDK) into the C3 crop wheat to generate transgenic wheat lines carrying cDNA of pepc (PC lines), ppdk (PK lines) or both (PKC lines). The integration, transcription, and expression of the foreign genes were confirmed by Southern blot, Real-time quantitative reverse transcription PCR (Q-RT-PCR), and Western blot analysis. Q-RT-PCR results indicated that the average relative expression levels of pepc and ppdk in the PKC lines reached 10 and 4.6, respectively, compared to their expressions in untransformed plants (set to 1). The enzyme activities of PEPC and PPDK in the PKC lines were 4.3- and 2.1-fold higher, respectively, than in the untransformed control. The maximum daily net photosynthetic rates of the PKC, PC, and PK lines were enhanced by 26.4, 13.3, and 4.5%, respectively, whereas the diurnal accumulations of photosynthesis were 21.3, 13.9, and 6.9%, respectively, higher than in the control. The Fv/Fm of the transgenic plants decreased less than in the control under high temperature and high light conditions (2 weeks after anthesis), suggesting that the transgenic wheat transports more absorbed light energy into a photochemical reaction. The exogenous maize C4-specific pepc gene was more effective than ppdk at improving the photosynthetic performance and yield characteristics of transgenic wheat, while the two genes showed a synergistic effect when they were transformed into the same genetic background, because the PKC lines exhibited improved photosynthetic and physiological traits.
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Preparation of cellulose based microspheres by combining spray coagulating with spray drying.
Carbohydr Polym
PUBLISHED: 02-08-2014
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Porous microspheres of regenerated cellulose with size in range of 1-2 ?m and composite microspheres of chitosan coated cellulose with size of 1-3 ?m were obtained through a two-step spray-assisted approach. The spray coagulating process must combine with a spray drying step to guarantee the formation of stable microspheres of cellulose. This approach exhibits the following two main virtues. First, the preparation was performed using aqueous solution of cellulose as precursor in the absence of organic solvent and surfactant; Second, neither crosslinking agent nor separated crosslinking process was required for formation of stable microspheres. Moreover, the spray drying step also provided us with the chance to encapsulate guests into the resultant cellulose microspheres. The potential application of the cellulose microspheres acting as drug delivery vector has been studied in two PBS (phosphate-buffered saline) solution with pH values at 4.0 and 7.4 to mimic the environments of stomach and intestine, respectively.
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Prevalence of Corneal Astigmatism in Patients before Cataract Surgery in Northern China.
J Ophthalmol
PUBLISHED: 02-07-2014
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Purpose. To analyze the prevalence and presentation patterns of corneal astigmatism in cataract surgery candidates in a teaching hospital in northern China. Methods. From May 1, 2012, to April 30, 2013, partial coherence interferometry (IOLMaster) measurements of all qualified cataract surgery candidates were retrospectively collected and analyzed. Results. The study evaluated 12,449 eyes from 6,908 patients with a mean age of 69.80 ± 11.15 (SD) years. The corneal astigmatism was 0.5 diopters (D) or less in 20.76% of eyes, 1.0?D or more in 47.27% of eyes, 2.0?D or more in 13.16% of eyes, and 3.0?D or more in 3.75% of eyes. With-the-rule astigmatism was found in 30.36% of eyes, while against-the-rule was found in 52.41% of eyes. The percentage of against-the-rule astigmatism increased with age. Conclusion. Our study showed that almost one-half of preoperative eyes (47.27%) in northern China have a corneal astigmatism of 1.0?D or more, indicating that more surgical techniques or toric IOLs are needed to achieve better visual rehabilitation.
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Effects of 5-azacytidine on RUNX3 gene expression and the biological behavior of esophageal carcinoma cells.
Mol Med Rep
PUBLISHED: 01-28-2014
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The present study investigated the effects of 5-azacytidine (5-azaC) on the expression level of the human runt-related transcription factor 3 (RUNX3) gene and the biological behavior of esophageal carcinoma Eca109 cells. The effect of the demethylation reagent 5-azaC on the viability of Eca109 cells was detected by the MTT assay, which demonstrated that 5-azaC inhibited the viability of Eca109 cells in a time- and dose-dependent manner. Although demethylation of other genes may occur following treatment with 5-azaC, we focused on the RUNX3 gene. When treated with 5-azaC at hypoxic levels, the expression of RUNX3 increased and the methylation degree of the RUNX3 gene was decreased significantly in Eca109 cells. 5-azaC at 50 µM demonstrated the highest RUNX3-induction activity, inducing RUNX3 mRNA and protein expression, and decreasing the degree of methylation of the RUNX3 gene. Methylation speci?c PCR indicated that 5-azaC induced RUNX3 expression through demethylation. The abilities of migration and invasion of Eca109 cells were inhibited by 5-azaC. The growth of Eca109 cells treated with 5-azaC in vivo was detected by a tumorigenesis experiment. 5-azaC inhibited the growth of Eca109 xenografts in nude mice. Taken together, our findings demonstrated that the RUNX3 gene is hypermethylated in Eca109 cells and that 5-azaC induces the expression of the RUNX3 gene by demethylation, which inhibits the proliferation, migration and invasion of Eca109 cells.
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Sensitive determination of reactive oxygen species in cigarette smoke using microchip electrophoresis-localized surface plasmon resonance enhanced fluorescence detection.
Lab Chip
PUBLISHED: 01-25-2014
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A sensitive approach to the determination of reactive oxygen species (ROS) in puffs of cigarette smoke (CS) has been developed. The experimental system consists of a microfluidic chip electrophoresis and a laser induced fluorescence (LIF) device enhanced by localized surface plasmon resonance. Core-shell Ag@SiO2 nanoparticles were prepared and then immobilized on the surface of the microchannel to increase the fluorescence intensity based on localized surface plasmon resonance-enhanced fluorescence (LSPREF) effect. The ROS in puffs of CS were trapped via the oxidation of 2',7'-dichlorodihydrofluorescein (DCHF) that had been loaded on polyacrylonitrile (PAN) nanofibers in a micro-column. Determination of ROS was based on the amount of 2',7'-dichlorofluorescein (DCF), which is the sole product from DCHF oxidation. With the optimization of the trapping efficiency, we detected about 8.0 pmol of ROS per puff in the mainstream CS. This microchip electrophoresis-SPREF system enables sensitive quantitation of ROS in CS with low consumption of reagent, material, and analysis time.
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The complete mitochondrial genome of western painted turtle, Chrysemys picta bellii (Chrysemys, Emydidae).
Mitochondrial DNA
PUBLISHED: 01-21-2014
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Abstract In this study, we report the complete mitochondrial genome sequence of western painted turtle, Chrysemys picta bellii. The genome is found to be 16,875?bp in length and has a base composition of A (34.4%), G (13.0%), C (26.0%), and T (26.6%). Similar to other turtles, it contains a typically conserved structure including 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 1 control region (D-loop). Most of the genes are encoded on H-strand, except for the eight tRNA and ND6 genes. All protein-coding genes start with an ATN codon except for COX1 and ND4, which initiate with GTG instead, and terminate with the typical stop codon (TAA/TAG) or a single T (T-) or an unexpected codon of AGG. The complete mitochondrial genome sequence provided here would be useful for further phylogenetic analysis and conservation genetic studies in C. p. bellii.
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Electrochemical immunosensor for detection of topoisomerase based on graphene-gold nanocomposites.
Talanta
PUBLISHED: 01-09-2014
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A facile electrochemical immunosensor based on graphene-three dimensional nanostructure gold nanocomposites (G-3D Au) using simple and rapid one-step electrochemical co-reduction technique was developed for sensitive detection of topoisomerase. The resultant G-3D Au nanocomposites were characterized by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy, and then were used as a substrate for construction of the "sandwich-type" immunosensor. Amperometric current-time curve was employed to monitor the immunoreaction on the protein modified electrode. The proposed method could respond to topoisomerase with a linear calibration range from 0.5 ng mL(-1) to 50 ng mL(-1) with a detection limit of 10 pg mL(-1). This new biosensor exhibited a fast amperometric response, high sensitivity and selectivity, and was successfully used in determining the topoisomerase which was added in human serum with a relative standard deviation (n=5)<5%. The immunosensor served as a significant step toward the practical application of the immunosensor in clinical diagnosis and prognosis monitor.
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Relationship of serum levels of VEGF and TGF-?1 with radiosensitivity of elderly patients with unresectable non-small cell lung cancer.
Tumour Biol.
PUBLISHED: 01-06-2014
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This study aimed to evaluate the relationship of serum levels of vascular endothelial growth factor (VEGF) and transforming growth factor-?1 (TGF-?1) with radiosensitivity of elderly patients with unresectable non-small cell lung cancer (NSCLC) receiving three-dimensional conformal radiation therapy (3D-CRT). Fifty-eight elderly patients with unresectable NSCLC and 40 healthy controls were enrolled in this study. Serum levels of VEGF and TGF-?1 were detected by the enzyme-linked immunosorbent assay (ELISA) method before and after 3D-CRT. Clinical performances of serum VEGF and TGF-?1 levels in predicting radiosensitivity of NSCLC patients with 3D-CRT were evaluated. Serum VEGF and TGF-?1 levels of NSCLC patients were higher than those of health controls (all p??0.05). Serum levels of VEGF and TGF-?1 after 3D-CRT in the effective group were lower compared with the levels before 3D-CRT treatment (p?
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Osmoprotectants suppress the production and activity of matrix metalloproteinases induced by hyperosmolarity in primary human corneal epithelial cells.
Mol. Vis.
PUBLISHED: 01-01-2014
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Hyperosmolarity has been recognized as a proinflammatory stress in the pathogenesis of dry eye disease. This study investigated the suppressive effect of osmoprotectants (L-carnitine, erythritol, and betaine) on the production and activity of matrix metalloproteinases (MMPs) in primary human corneal epithelial cells (HCECs) exposed to hyperosmotic stress.
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Surface modification of porous suspended ceramsite used for water treatment by activated carbon/Fe3O4 magnetic composites.
Environ Technol
PUBLISHED: 12-20-2013
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In this study, porous suspended ceramsite with a specific density close to that of water was prepared by high-temperature calcination using fly ash, feldspar, calcite, fired talc and kaolin as the raw materials. The ceramsite was modified by activated carbon/Fe3O4 magnetic composites. The optimum modification conditions determined by methylene blue adsorption experiment were: KOH/glucose ratio of 1.5:1, carbonization temperature of 400 degrees C, activation temperature of 850 degrees C, activation time of 1 h, and Fe3O4/KOH+glucose ratio of 1:10. The results demonstrated that the adsorption capacity of the modified ceramsite for methylene blue was significantly higher than that of the unmodified ones. The presence of the composites did not lead to significant decrease in the mechanical properties of the modified ceramsite. Moreover, the modified ceramsite showed good resistance towards acid and alkali. The modified ceramsite can be used as biocarrier and adsorbent for a wide range of contaminants in water and can subsequently be removed from the medium by a simple magnetic procedure.
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Alteration of runt-related transcription factor 3 gene expression and biologic behavior of esophageal carcinoma TE-1 cells after 5-azacytidine intervention.
Asian Pac. J. Cancer Prev.
PUBLISHED: 11-02-2013
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5-Azacytidine (5-azaC) was originally identified as an anticancer drug (NSC102876) which can cause hypomethylation of tumor suppressor genes. To assess its effects on runt-related transcription factor 3 (RUNX3), expression levels and the promoter methylation status of the RUNX3 gene were assessed. We also investigated alteration of biologic behavior of esophageal carcinoma TE-1 cells. MTT assays showed 5-azaC inhibited the proliferation of TE-1 cells in a time and dose-dependent way. Although other genes could be demethylated after 5-azaC intervention, we focused on RUNX3 gene in this study. The expression level of RUNX3 mRNA increased significantly in TE-1 cells after treatment with 5-azaC at hypotoxic levels. RT-PCR showed 5-azaC at 50 ?M had the highest RUNX3-induction activity. Methylation-specific PCR indicated that 5-azaC induced RUNX3 expression through demethylation. Migration and invasion of TE-1 cells were inhibited by 5-azaC, along with growth of Eca109 xenografts in nude mice. In conclusion, we demonstrate that the RUNX3 gene can be reactivated by the demethylation reagent 5-azaC, which inhibits the proliferation, migration and invasion of esophageal carcinoma TE-1 cells.
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[Exposure degree of important non-target arthropods to Cry2Aa in Bt rice fields].
Ying Yong Sheng Tai Xue Bao
PUBLISHED: 09-27-2013
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Based on the principle of "risk = hazard x exposure", the selected representative nontarget organisms in the assessment of the potential effects of insect-resistant genetically modified (GM) crops on non-target arthropods in laboratory are generally the arthropod species highly exposed to the insecticidal proteins expressed by the GM crops in farmland ecosystem. In order to understand the exposure degree of the important arthropod species to Cry proteins in Bt rice fields, and to select the appropriate non-target arthropods in the risk assessment of insect-resistant GM crops, the enzyme-linked immunosorbent assay (ELISA) was conducted to measure the Cry2Aa protein concentration in the arthropods collected from the cry2Aa rice fields at different rice growth stages. The results showed that there was a significant difference in the Cry2Aa content protein concentration in different arthropod species. Some species did not contain Cry2Aa protein, while some species contained larger amounts of Cry2Aa protein. Relative to the arthropods colleted after rice anthesis, the arthropods colleted in rice anthesis contained relative higher concentrations of Cry2Aa protein, especially for the predacious arthropods. No Cry proteins were detected in parasitic arthropods. This study provided references for the laboratory assessment of the effects of GM rice on nontarget arthropods.
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An IMPLICATION logic gate based on citrate-capped gold nanoparticles with thiocyanate and iodide as inputs.
Analyst
PUBLISHED: 09-20-2013
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Herein we developed an IMPLICATION logic gate based on citrate-capped AuNPs by employing thiocyanate (SCN(-)) and iodide (I(-)) as inputs, and devised a colorimetric sensor for the determination of I(-) with good selectivity and sensitivity. To the best of our knowledge, this is the first example in which two species of anions serve as inputs to obtain visually observed Boolean outputs. Under the optimum conditions, 0.8 ?M I(-) could induce a significant color change and be recognized by the naked eye. The detection limit is 50 nM by using UV-vis spectroscopy.
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Self-assembly of large-scale floating TiO2 nanorod arrays at the gas-liquid interface.
ACS Appl Mater Interfaces
PUBLISHED: 09-04-2013
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This paper describes a facile one-step synthesis of large-scale floating TiO2 nanorod arrays via a hydrothermal reaction without using any surfactants, which opens a new way to prepare floating photocatalysts for photodecomposition of floating organics and free-standing nanorod arrays for flexible dye-sensitized solar cells. A general model is developed to analyze the driving force for the floating TiO2 film, which may be also useful for other two-dimensional materials to determine the obtainable size of an arbitrary shaped film floated by surface tension and buoyancy.
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Sensitive label-free monitoring of protein kinase activity and inhibition using ferric ions coordinated to phosphorylated sites as electrocatalysts.
Chem. Commun. (Camb.)
PUBLISHED: 08-21-2013
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Ferric ions show high affinity to the kinase-generated phosphorylated sites of peptides. Thus, the high electrocatalytic activity of the coordinated ferric ions toward the reduction of hydrogen peroxide can be used for sensitive label-free monitoring of protein kinase activity and inhibition.
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On-chip selective capture of cancer cells and ultrasensitive fluorescence detection of survivin mRNA in a single living cell.
Lab Chip
PUBLISHED: 08-06-2013
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The rapid recognition of cancer cells and detection of tumor biomarker survivin mRNA plays a critical role in the early diagnosis of many cancers. Based on the integration of specific cancer cell capture and intracellular survivin mRNA detection, this work presents a novel and sensitive on-chip approach for the bioanalysis of survivin mRNA in a single living cell. The microchannel surface was firstly modified with a prostate stem cell antigen (PSCA) monoclonal antibody as the recognition element for prostate cancer cells (PC-3). As a result of the antigen-antibody specific affinity interactions, PC-3 cells could be selectively captured on the microchannel surface. After cell capture, nano-sized graphene oxide-poly(ethylene glycol) bis(amine) (NGO-PEG) was employed as a quencher and carrier of a signal tag, fluorescein isothiocyanate (FITC)-labeled antisense oligonucleotide (F-S1), which is complementary to part of survivin mRNA (target survivin mRNA), to transfect into the captured PC-3 cells. Upon the selective binding of S1 to intracellular survivin mRNA, F-S1 will be released from the NGO-PEG, inducing the fluorescence recovery of FITC. This antibody-based microfluidic device enables simple and inexpensive monitoring of the amount of survivin mRNA in single captured cell without the need for sample pretreatment. The survivin mRNA content in each PC-3 cell was estimated to be (4.8 ± 1.8) × 10(6) copies. This strategy opens a different perspective for ultrasensitive survivin mRNA detection, which may facilitate the early screening for malignancy.
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Dependence of the direct electron transfer activity and adsorption kinetics of cytochrome c on interfacial charge properties.
Analyst
PUBLISHED: 08-06-2013
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With the advantages of in situ analysis and high surface sensitivity, surface-enhanced infrared absorption spectroscopy in attenuated total reflection mode (ATR-SEIRAS) combined with electrochemical methods has been employed to examine the interfacial direct electron transfer activity and adsorption kinetics of cytochrome c (cyt c). This work presents data on cyt c adsorption onto negatively charged mercaptohexanoic acid (MHA) and positively charged 6-amino-1-hexanethiol (MHN) self-assembled monolayers (SAMs) on gold nanofilm surfaces. The adsorbed cyt c displays a higher apparent electron transfer rate constant (33.5 ± 2.4 s(-1)) and apparent binding rate constant (73.1 ± 5.2 M(-1) s(-1)) at the MHA SAMs surface than those on the MHN SAMs surface. The results demonstrate that the surface charge density determines the protein adsorption kinetics, while the surface charge character determines the conformation and orientation of proteins assembled which in turn affects the direct electron transfer activity.
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[Expression of urinary neutrophil gelatinase-associated lipocalin and its clinical significance in children with idiopathic nephrotic syndrome].
Zhongguo Dang Dai Er Ke Za Zhi
PUBLISHED: 07-20-2013
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To investigate the urinary neutrophil gelatinase-associated lipocalin (NGAL) concentration in children with idiopathic nephrotic syndrome (INS) and its clinical significance.
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[Study on the rule of influence of two purification methods on the chemical compositions in aqueous solution of paeoniae radix alba].
Zhong Yao Cai
PUBLISHED: 06-12-2013
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To explore the rule of influence of chitosan flocculation clarification and alcohol precipitation on the chemical compositions in aqueous extract of Paeoniae Radix Alba.
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Graphene-Ruthenium(II) Complex Composites for Sensitive ECL Immunosensors.
Small
PUBLISHED: 05-22-2013
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Non-covalent modi?cation method has been proven as an effective strategy for enhancing the chemical properties of graphene while the structure and electronic properties of graphene can be retained. This work describes a novel strategy to fabricate a solid-state electrochemiluminescent (ECL) immunosensor based on ruthenium(II) complex/3,4,9,10-perylenetetracarboxylic acid (PTCA)/graphene nanocomposites (Ru-PTCA/G) for sensitive detection of ?-fetoprotein (AFP). It is found that immobilization of PTCA and reduction of GO can be simultaneously achieved in one-pot synthesis method under alkaline condition and moderate temperature, forming PTCA/G nanocomposites. Further covalent attachment of ruthenium(II) complex to the PTCA assembled on graphene sheets produces the functional Ru-PTCA/G nanocomposites which show good electrochemical activity and ca. 21 times higher luminescence quantum efficiency than the adsorbed derivative ruthenium(II) complex. The Ru-PTCA/G nanocomposites based solid-state ECL sensor exhibits high stability toward the determination of tripropylamine (TPA) coreactant. In addition, a new ECL immunosensor based on steric hindrance effect is fabricated by cross-linking ?-fetoprotein antibody (anti-AFP) with chitosan covered on Ru-PTCA/G composites modi?ed electrode for detection of cancer biomarker AFP. This ECL immunosensor shows an extremely sensitive response to AFP in a linear range of 5 pg·mL(-1) -10 ng·mL(-1) with a detection limit of 0.2 pg·mL(-1) . The present approach is effective for various molecules immobilization and may become a promising technique for biomolecular detection.
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How does climate influence speciation?
Am. Nat.
PUBLISHED: 05-15-2013
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Variation in climatic conditions over space and time is thought to be an important driver of speciation. However, the role of climate has not been explored in the theoretical literature on speciation, and the theory underlying empirical studies of climate and speciation has come largely from informal, verbal models. In this study, we develop a quantitative model to test a relatively new but theoretically untested model of speciation (speciation via niche conservatism) and to examine the climatic conditions under which speciation via niche conservatism and speciation via niche divergence are most plausible. Our results have three broad implications for the study of speciation: (1) ecological similarity over time (niche conservatism) can be an important part of speciation, despite the traditional emphasis on ecological divergence, (2) long-term directional climate change promotes speciation via niche conservatism for species with low climatic-niche lability, whereas climatic oscillations promote speciation via niche divergence for species with high climatic-niche lability, and (3) population extinction can be a key component of speciation.
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Lagrangian scale of particle dispersion in turbulence.
Nat Commun
PUBLISHED: 05-14-2013
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Transport of mass, heat and momentum in turbulent flows by far exceeds that in stable laminar fluid motions. As turbulence is a state of a flow dominated by a hierarchy of scales, it is not clear which of these scales mostly affects particle dispersion. Also, it is not uncommon that turbulence coexists with coherent vortices. Here we report on Lagrangian statistics in laboratory two-dimensional turbulence. Our results provide direct experimental evidence that fluid particle dispersion is determined by a single measurable Lagrangian scale related to the forcing scale. These experiments offer a new way of predicting dispersion in turbulent flows in which one of the low energy scales possesses temporal coherency. The results are applicable to oceanographic and atmospheric data, such as those obtained from trajectories of free-drifting instruments in the ocean.
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Rapid quantitative analysis of diosgenin in the tubers of Dioscorea zingiberensis C.H. Wright by coupling cellulose enzymolysis and two-phase acid hydrolysis in tandem with HPLC-UV.
Nat. Prod. Res.
PUBLISHED: 05-14-2013
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A rapid method was developed to quantify diosgenin in Rhizoma Dioscoreae Zingiberensis. For the first time, sample solution was prepared by coupling pretreatment of raw material in cellulase and two-phase acid hydrolysis. After reconstitution, analysis was carried out on a C18 column, at 30°C, with acetonitrile and water (70:30, v/v) as mobile phase with flow rate of 1.0 mL min(- 1). Detection was carried out at 202 nm. Good linearity (r(2) = 0.9998) was established between concentration of analyte and peak area. The precision was >99% and the RSD of diosgenin contents for repeatability was 1.81%. The accuracy was supported with recoveries at 98.8%, 101.6% and 101.2%. The sample solution prepared using the proposed method contained higher content of diosgenin and was stable for 48 h. Due to the high efficiency of sample preparation and high reliability of the HPLC method, it is feasible to use this method for routine analysis of diosgenin in the herb.
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[Effect of silencing AEG-1 with small interfering RNA on the proliferation and cell cycle of gastric carcinoma SGC-7901 cells].
Zhonghua Zhong Liu Za Zhi
PUBLISHED: 05-08-2013
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To explore the effect of down-regulation of astrocyte elevated gene-1 (AEG-1) expression on cell proliferation and cell cycle of gastric carcinoma cells, and its possible molecular mechanism.
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[Efficacy of probiotics on ulcerative colitis and its mechanism].
Zhonghua Wei Chang Wai Ke Za Zhi
PUBLISHED: 04-24-2013
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To evaluate the efficacy of probiotics on the treatment outcomes of ulcerative colitis, and explore its possible mechanism.
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Effects of PTTG Down-regulation on Proliferation and Metastasis of the SCL-1 Cutaneous Squamous Cell Carcinoma Cell Line.
Asian Pac. J. Cancer Prev.
PUBLISHED: 04-09-2013
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Aims: To study effects of down-regulation of pituitary tumor-transforming gene (PTTG) on proliferation and metastasis ability of the SCL-1 cutaneous squamous cell carcinoma (CSCC) cell line and explore related mechanisms. Methods: SCL-1 cells were divided into 3 groups (untreated, siRNA control and PTTG siRNA). Cell proliferation assays were performed using a CCK-8 kit and proliferation and metastasis ability were analyzed using Boyden chambers. In addition, expression of MMP-2 and MMP-9 was detected by r-time qPCR and Western blotting. Results: Down-regulation of PTTG could markedly inhibit cell proliferation in SCL-1 cells, compared to untreated and control siRNA groups (P < 0.05). Real-time qPCR demonstrated that expression levels of PTTG, MMP-2 and MMP-9 in the PTTG siRNA group were 0.8%, 23.2% and 21.3% of untreated levels. Western blotting revealed that expression of PTTG, MMP-2 and MMP-9 proteins in the PTTG siRNA group was obviously down-regulated. The numbers of migrating cells (51.38±4.71) in the PTTG siRNA group was obviously lower than that in untreated group (131.33±6.12) and the control siRNA group (127.72±5.20) (P < 0.05), suggesting that decrease of proliferation and metastasis ability mediated by PTTG knock-down may be closely correlated with down-regulation of MMP-2 and MMP-9 expression. Conclusion: Inhibition of PTTG expression may be a new target for therapy of CSCC.
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Blood flow of the acral finger arterioles in patients with type 2 diabetes by quality Doppler profiles.
Cell Biochem. Biophys.
PUBLISHED: 03-26-2013
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Patients with diabetes mellitus exhibit peripheral arterioles lesions that is associated with reduced blood flow. Here, we intended to assess the acral arterioles lesion in patients with type 2 diabetes based on the rate of blood flow by multigate spectral Doppler ultrasonography. Fifty-two patients with type 2 DM were divided into two groups. Group 1 included 13 men and 12 women with an average age of 60.60 ± 14.03 years and a duration of type 2 diabetes for 2.44 ± 1.50 years. Group 2 included 17 men and 11 women with an average age of 64.25 ± 10.84 years and type 2 diabetes for 12.57 ± 6.26 years. Age-matched control subjects (n = 52) were recruited (30 men and 22 woman, mean age of 61.19 ± 10.38 years). A multigate spectral Doppler algorithm was applied to the acral finger of the thumb of the right hand to test the arteriole diameter and hemodynamic parameters, including diameter of the acral finger arterioles (D), area of the blood flow profile of the acral finger arterioles (A max) and hemodynamic parameters. Patients with diabetes exhibited a significant reduction in the arteriole diameter (1.63 ± 0.18 and 1.57 ± 0.22 mm, respectively, P < 0.001 for both) compared to control subjects (2.09 ± 0.17 mm). A max were significantly reduced in patients with diabetes (61.35 ± 10.66 mm(2)/s for group 1 and 46.50 ± 6.59 mm(2)/s for group 2, P < 0.001 for both) compared to that in control subjects (77.93 ± 12.37 mm(2)/s). Furthermore, a significant difference in Amax was found between group 1 and group 2 (P < 0.001). The vascular resistance index (RI) was significantly higher in both patient groups 0.58 ± 0.06 for group 1 (P < 0.001) and 0.64 ± 0.07 for group 2 (P < 0.001) than that in control subjects (0.48 ± 0.04). The RI value of the acral finger arterioles differed significantly between group 1 and group 2 (P < 0.01). Diabetic patients exhibited a weak blood flow in the acral finger arterioles. The multigate spectral Doppler technology can be used to test blood flow in the acral finger arterioles and provide hemodynamic data for systematic analyses of the peripheral arteriole lesions in diabetes.
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Colorimetric sensor based on dual-functional gold nanoparticles: analyte-recognition and peroxidase-like activity.
Food Chem
PUBLISHED: 03-22-2013
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A novel colorimetric sensor based on the interaction ability with specific analytes and peroxidase-like activity of gold nanoparticles was established in this work. Combining the high-affinity binding between bare gold nanoparticles and melamine with signal amplification procedure based on the catalytic activity of gold nanoparticles for oxidation of TMB, melamine with the concentration as low as 0.02 mg/L can be easily distinguished by naked-eye observation. Such system can be adapted through carefully-controlled surface modifications of gold nanoparticles for determination of other targets.
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[Effect of gambogic acid on proliferation of SKM-1 cells and its mechanism].
Zhongguo Shi Yan Xue Ye Xue Za Zhi
PUBLISHED: 03-15-2013
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The aim of this study was to explore the effect of gambogic acid (GA) on MDS SKM-1 cell proliferation, apoptosis and their possible mechanism. Cell proliferation was determined by MTT method. The apoptosis percentage and cell cycle regulation of SKM-1 cells were analyzed by flow cytometry. Morphological features were observed by light microscopy. The mRNA expression of bcl-2 and bax were detected by RT-PCR. The results showed that GA could inhibit the proliferation of SKM-1 cells in a dose- and time-dependent manner (IC50 was 0.37 µg/ml at 48 h), increase the apoptotic percentage of SKM-1 cells, and arrest cell cycle at the G0/G1. The expression of bax mRNA was up-regulated while that of bcl-2 mRNA was down-regulated in SKM-1 cells treated with GA for 48 h. It is concluded that GA can induce apoptosis, which may be related to its effect of arresting cells at phase of G0/G1 and down-regulating bcl-2/bax ratio.
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Synergistic antitumor activity of reversine combined with aspirin in cervical carcinoma in vitro and in vivo.
Cytotechnology
PUBLISHED: 03-10-2013
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A recent report showed that reversine treatment could induce murine myoblasts dedifferentiation into multipotent progenitor cells and inhibit proliferation of some tumors, and other reports showed that apoptosis of lung adenocarcinoma cells could be induced by aspirin. The aim of the present study was to evaluate the synergistic antitumor effects of reversine and aspirin on cervical cancer. The inhibition rate of reversine and aspirin on cervical cancer cell lines (HeLa and U14) was determined by MTT method, cell cycle of HeLa and U14 cells was analyzed by FACS, mitochondrial membrane potential of HeLa and U14 was detected using a JC-1 kit. HeLa and U14 colony formation was analyzed by soft agar colony formation assay. The expression of caspase-3, Bcl-2/Bax, cyclin D1 and p21 was detected by qRT-PCR and Western Blotting. Moreover, tumor weight and tumor volume was assessed using a murine model of cervical cancer with U14 cells subcutaneously (s.c.) administered into the neck, separately or combined with drug administration via the intraperitoneal (i.p.) route. The inhibition rate of cells in the combination group (10 ?mol/L reversine, 10 mmol/L aspirin) increased significantly in comparison to that when the drugs were used alone (P < 0.05); moreover, this combination could synergistically inhibit the proliferation of five cervical cancer cell lines (HeLa, U14, Siha, Caski and C33A). In the therapeutic mouse model, tumor weight and tumor volume of cervical cancer bearing mice was more reduced when compared with the control agents (P < 0.05) in tumor-bearing mice. The combination of reversine and aspirin exerts synergistic growth inhibition and apoptosis induction on cervical cancers cells.
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Handy, rapid and multiplex detection of tumor markers based on encoded silica-hydrogel hybrid beads array chip.
Biosens Bioelectron
PUBLISHED: 02-25-2013
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Malignant tumor has become the leading cause of death worldwide; however, multiplex detection technology could provide great assistance in large-scale population screening of diseases which could effectively reduce the mortality of malignant tumors. Here a microbeads array chip, which could be a perfect alternative method for the early screening, was developed. Silica-hydrogel hybrid bead (SHHB) with photonic encoding, which consists of both silica and hydrogel materials, was manufactured as the carrier of microbeads array for the first time. The SHHB has the advantages of the beads made of silica or hydrogel, but does not have their limitations. Reaction conditions of SHHBs array were optimized and then the fluorescent concentration curves of two widely-used tumor markers, human alpha fetoprotein and carcinoembryonic antigen, were constructed. The accuracy of SHHBs array has been proven according to the comparison between the results obtained by detecting 50 clinical samples with SHHBs array and chemiluminescence immunoassay. A cassette like chip device has also been developed to standardize operational processes and benefit automization in the next work. Hence it is concluded that SHHBs array chip is a handy, rapid and multiplex immunoassay technology, which could imply its practical application in clinical immunoassay in the near future.
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Insights into the "free state" enzyme reaction kinetics in nanoconfinement.
Lab Chip
PUBLISHED: 02-22-2013
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The investigation of enzyme reaction kinetics in nanoconfined spaces mimicking the conditions in living systems is of great significance. Here, a nanofluidics chip integrated with an electrochemical detector has been designed for studying "free state" enzyme reaction kinetics in nanoconfinement. The nanofluidics chip is fabricated using the UV-ablation technique developed in our group. The enzyme and substrate solutions are simultaneously supplied from two single streams into a nanochannel through a Y-shaped junction. The laminar flow forms in the front of the nanochannel, then the two liquids fully mix at their downstream where a homogeneous enzyme reaction occurs. The "free state" enzyme reaction kinetics in nanoconfinement can thus be investigated in this laminar flow based nanofluidics device. For demonstration, glucose oxidase (GOx) is chosen as the model enzyme, which catalyzes the oxidation of beta-d-glucose. The reaction product hydrogen peroxide (H2O2) can be electrochemically detected by a microelectrode aligning to the end of nanochannel. The steady-state electrochemical current responding to various glucose concentrations is used to evaluate the activity of the "free state" GOx under nanoconfinement conditions. The effect of liquid flow rate, enzyme concentration, and nanoconfinement on reaction kinetics has been studied in detail. Results show that the "free state" GOx activity increases significantly compared to the immobilized enzyme and bath system, and the GOx reaction rate in the nanochannel is two-fold faster than that in bulk solution, demonstrating the importance of "free state" and spatial confinement for the enzyme reaction kinetics. The present approach provides an effective method for exploiting the "free state" enzyme activity in nanospatial confinement.
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HIV and hepatitis C virus test uptake at methadone clinics in Southern China: opportunities for expanding detection of bloodborne infections.
BMC Public Health
PUBLISHED: 02-15-2013
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HIV and hepatitis C (HCV) co-infection is highly common among Chinese injection drug users but it is difficult to reach IDUs at traditional VCT (Voluntary HIV counseling treatment) clinics. A new national model integrating HIV/HCV testing with methadone maintenance treatment was started in 2006. The purpose of this study was to investigate HIV and HCV test uptake and associated factors at methadone clinics in Guangdong Province, China.
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Contradiction between plastid gene transcription and function due to complex posttranscriptional splicing: an exemplary study of ycf15 function and evolution in angiosperms.
PLoS ONE
PUBLISHED: 02-15-2013
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Plant chloroplast genes are usually co-transcribed while its posttranscriptional splicing is fairly complex and remains largely unsolved. On basis of sequencing the three complete Camellia (Theaceae) chloroplast genomes for the first time, we comprehensively analyzed the evolutionary patterns of ycf15, a plastid gene quite paradoxical in terms of its function and evolution, along the inferred angiosperm phylogeny. Although many species in separate lineages including the three species reported here contained an intact ycf15 gene in their chloroplast genomes, the phylogenetic mixture of both intact and obviously disabled ycf15 genes imply that they are all non-functional. Both intracellular gene transfer (IGT) and horizontal gene transfer (HGT) failed to explain such distributional anomalies. While, transcriptome analyses revealed that ycf15 was transcribed as precursor polycistronic transcript which contained ycf2, ycf15 and antisense trnL-CAA. The transcriptome assembly was surprisingly found to cover near the complete Camellia chloroplast genome. Many non-coding regions including pseudogenes were mapped by multiple transcripts, indicating the generality of pseudogene transcriptions. Our results suggest that plastid DNA posttranscriptional splicing may involve complex cleavage of non-functional genes.
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Prevalent role of gene features in determining evolutionary fates of whole-genome duplication duplicated genes in flowering plants.
Plant Physiol.
PUBLISHED: 02-08-2013
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The evolution of genes and genomes after polyploidization has been the subject of extensive studies in evolutionary biology and plant sciences. While a significant number of duplicated genes are rapidly removed during a process called fractionation, which operates after the whole-genome duplication (WGD), another considerable number of genes are retained preferentially, leading to the phenomenon of biased gene retention. However, the evolutionary mechanisms underlying gene retention after WGD remain largely unknown. Through genome-wide analyses of sequence and functional data, we comprehensively investigated the relationships between gene features and the retention probability of duplicated genes after WGDs in six plant genomes, Arabidopsis (Arabidopsis thaliana), poplar (Populus trichocarpa), soybean (Glycine max), rice (Oryza sativa), sorghum (Sorghum bicolor), and maize (Zea mays). The results showed that multiple gene features were correlated with the probability of gene retention. Using a logistic regression model based on principal component analysis, we resolved evolutionary rate, structural complexity, and GC3 content as the three major contributors to gene retention. Cluster analysis of these features further classified retained genes into three distinct groups in terms of gene features and evolutionary behaviors. Type I genes are more prone to be selected by dosage balance; type II genes are possibly subject to subfunctionalization; and type III genes may serve as potential targets for neofunctionalization. This study highlights that gene features are able to act jointly as primary forces when determining the retention and evolution of WGD-derived duplicated genes in flowering plants. These findings thus may help to provide a resolution to the debate on different evolutionary models of gene fates after WGDs.
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Knockdown of myeloid differentiation protein-2 reduces acute lung injury following orthotopic autologous liver transplantation in a rat model.
Pulm Pharmacol Ther
PUBLISHED: 01-22-2013
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Acute lung injury (ALI) is a serious complication that commonly occurs during orthotopic liver transplantation (OLT). Toll-like receptor 2/4 (TLR2/4) are the main membrane receptors that respond to inflammatory stimuli and mediate NF-kappa B (NF-?B) signal pathway. We previously showed that TLR2/4 expression on monocytes and serum cytokine levels were increased in patients with ALI induced by OLT. Myeloid differentiation protein-2 (MD-2) expresses the functional domains that combines TLRs and play a key regulatory role in TLRs activation. Therefore, we hypothesized that blocking MD-2 would inhibit the TLR2/4-mediated inflammatory response and lessen ALI induced by liver transplantation.
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