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Find video protocols related to scientific articles indexed in Pubmed.
Clonal Spread of Catalase-Negative ST5/SCCmec II Staphylococcus aureus Carrying the Staphylococcal Enterotoxin A (Sea), Staphylococcal Enterotoxin B (Seb), and Toxic Shock Toxin (Tst) Virulence Genes.
Ann. Clin. Lab. Sci.
PUBLISHED: 11-02-2014
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17 catalase-negative methicillin-resistant Staphylococcus aureus (MRSA) isolates were recovered from respiratory specimens of patients at a 700-bed hospital in Korea. The goal of this study was to determine the molecular characteristics of catalase-negative MRSA strains in Korea for the first time. Characteristics that we explored included kat A gene mutation sequence, sequence type, staphylococcal cassette chromosome (SCC) mec subtype classification, and toxin gene profiles. All 17 isolates showed similar pulsed field gel electrophoresis (PFGE) pattern. Four mutations were identified in the kat A gene of a representative catalase-negative MRSA strain: A602G causing a histidine 201 to arginine change, A695T causing a glutamic acid 232 to valine change, T778A causing a tryptophan 260 to arginine change, and G1438A causing a glycine 480 to serine change. Previous studies suggest that the A695T and T778A mutations may have strong effects on the catalase activity of catalase-negative MRSA. The sequence type (ST) and SCCmec type of this isolate were ST 5 and SCCmec type II, respectively. All 17 isolates harbored toxic shock toxin (tst), staphylococcal enterotoxin A (sea), and staphylococcal enterotoxin B (seb) virulence genes. The mortality rate of the present study was 11.8%, suggesting that the clinical relevance of catalase-negative MRSA requires further study in the future.
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Surface charge regulation of carboxyl terminated polystyrene latex particles and their interactions at the oil/water interface.
Langmuir
PUBLISHED: 10-07-2014
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We study electrostatic interactions of polystyrene particles at an oil/water interface controlled by a chemical reaction of carboxylate surface functional groups. By replacing the carboxyl functional groups with hydrocarbon chains using the well-known EDC (1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide) coupling reaction, the surface charge density decreases while the hydrophobicity of the colloid surface increases. Direct visualization of the particle-laden interface reveals that, depending on the extent of hydrocarbon coupling, the strength of the electrostatic repulsion can be regulated: the repulsive interaction increases with the reaction, removing aggregates, but rapidly decreases if the reaction proceeds too much, forming a large aggregation. This simple reaction, thus, dramatically changes the structures of the colloidal monolayers at the oil/water interface. We conclude that such structural change is the result of change of the repulsive interactions from the oil phase, although interactions in the water phase are also changed slightly.
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Cotransport of multi-walled carbon nanotubes and titanium dioxide nanoparticles in saturated porous media.
Environ. Pollut.
PUBLISHED: 09-02-2014
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The cotransport of multi-walled carbon nanotubes (MWCNTs) and nanoscaled titanium dioxide (nano-TiO2) in porous media were investigated in 1 and 10 mM NaCl at both pH 5 and 7. Nano-TiO2 decreased MWCNTs transport under all conditions. The increased MWCNTs deposition at pH 5 was due to MWCNTs deposition onto previously deposited nano-TiO2 and codeposition of nano-TiO2-MWCNTs aggregates; whereas, codeposition of nano-TiO2-MWCNTs aggregates contributed to the increased MWCNTs deposition at pH 7. MWCNTs increased nano-TiO2 transport under all conditions except in 10 mM NaCl at pH 5. MWCNTs facilitated transport drove to the increased nano-TiO2 transport in 1 mM NaCl at pH 5; whereas, competition of deposition sites and stabilization of nano-TiO2 by MWCNTs mainly caused the increased nano-TiO2 transport at pH 7. Although MWCNTs didn't affect nano-TiO2 breakthrough curve in 10 mM NaCl at pH 5, concurrent aggregation induced straining yet shifted nano-TiO2 retained profile from log-linear to hyper-exponential decreases.
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Demonstration of feasibility of X-ray free electron laser studies of dynamics of nanoparticles in entangled polymer melts.
Sci Rep
PUBLISHED: 08-11-2014
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The recent advent of hard x-ray free electron lasers (XFELs) opens new areas of science due to their exceptional brightness, coherence, and time structure. In principle, such sources enable studies of dynamics of condensed matter systems over times ranging from femtoseconds to seconds. However, the studies of "slow" dynamics in polymeric materials still remain in question due to the characteristics of the XFEL beam and concerns about sample damage. Here we demonstrate the feasibility of measuring the relaxation dynamics of gold nanoparticles suspended in polymer melts using X-ray photon correlation spectroscopy (XPCS), while also monitoring eventual X-ray induced damage. In spite of inherently large pulse-to-pulse intensity and position variations of the XFEL beam, measurements can be realized at slow time scales. The X-ray induced damage and heating are less than initially expected for soft matter materials.
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Influence of clay particles on the transport and retention of titanium dioxide nanoparticles in quartz sand.
Environ. Sci. Technol.
PUBLISHED: 06-17-2014
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This study investigated the influence of two representative suspended clay particles, bentonite and kaolinite, on the transport of titanium dioxide nanoparticles (nTiO2) in saturated quartz sand in both NaCl (1 and 10 mM ionic strength) and CaCl2 solutions (0.1 and 1 mM ionic strength) at pH 7. The breakthrough curves of nTiO2 with bentonite or kaolinite were higher than those without the presence of clay particles in NaCl solutions, indicating that both types of clay particles increased nTiO2 transport in NaCl solutions. Moreover, the enhancement of nTiO2 transport was more significant when bentonite was present in nTiO2 suspensions relative to kaolinite. Similar to NaCl solutions, in CaCl2 solutions, the breakthrough curves of nTiO2 with bentonite were also higher than those without clay particles, while the breakthrough curves of nTiO2 with kaolinite were lower than those without clay particles. Clearly, in CaCl2 solutions, the presence of bentonite in suspensions increased nTiO2 transport, whereas, kaolinite decreased nTiO2 transport in quartz sand. The attachment of nTiO2 onto clay particles (both bentonite and kaolinite) were observed under all experimental conditions. The increased transport of nTiO2 in most experimental conditions (except for kaolinite in CaCl2 solutions) was attributed mainly to the clay-facilitated nTiO2 transport. The straining of larger nTiO2-kaolinite clusters yet contributed to the decreased transport (enhanced retention) of nTiO2 in divalent CaCl2 solutions when kaolinite particles were copresent in suspensions.
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Nanoscopic management of molecular packing and orientation of small molecules by a combination of linear and branched alkyl side chains.
ACS Nano
PUBLISHED: 06-06-2014
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We synthesized a series of acceptor-donor-acceptor-type small molecules (SIDPP-EE, SIDPP-EO, SIDPP-OE, and SIDPP-OO) consisting of a dithienosilole (SI) electron-donating moiety and two diketopyrrolopyrrole (DPP) electron-withdrawing moieties each bearing linear n-octyl (O) and/or branched 2-ethylhexyl (E) alkyl side chains. X-ray diffraction patterns revealed that SIDPP-EE and SIDPP-EO films were highly crystalline with pronounced edge-on orientation, whereas SIDPP-OE and SIDPP-OO films were less crystalline with a radial distribution of molecular orientations. Near-edge X-ray absorption fine structure spectroscopy disclosed an edge-on orientation with a molecular backbone tilt angle of ?22° for both SIDPP-EE and SIDPP-EO. Our analysis of the molecular packing and orientation indicated that the shorter 2-ethylhexyl groups on the SI core promote tight ?-? stacking of the molecular backbone, whereas n-octyl groups on the SI core hinder close ?-? stacking to some degree. Conversely, the longer linear n-octyl groups on the DPP arms facilitate close intermolecular packing via octyl-octyl interdigitation. Quantum mechanics/molecular mechanics molecular dynamics simulations determined the optimal three-dimensional positions of the flexible alkyl side chains of the SI and DPP units, which elucidates the structural cause of the molecular packing and orientation explicitly. The alkyl-chain-dependent molecular stacking significantly affected the electrical properties of the molecular films. The edge-on oriented molecules showed high hole mobilities in organic field-effect transistors, while the radially oriented molecules exhibited high photovoltaic properties in organic photovoltaic cells. These results demonstrate that appropriate positioning of alkyl side chains can modulate crystallinity and molecular orientation in SIDPP films, which ultimately have a profound impact on carrier transport and photovoltaic performance.
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Porous Ca-based bead sorbents for simultaneous removal of SO2, fine particulate matters, and heavy metals from pilot plant sewage sludge incineration.
J. Hazard. Mater.
PUBLISHED: 05-29-2014
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In this study, a porous calcium-based sorbent was prepared for simultaneous removal of SO2, particulate matter (PM), and heavy metals generated during incineration of sewage sludge. The prepared sorbent was confirmed to have a 3-dimensional-network pore structure, a high specific surface area of 68.5m(2)/g, and gas permeability of 1.12×10(-10)m(2). Laboratory-scale tests indicated that there was an improvement in the performance of SO2 removal as the porosity and the specific surface area of the sorbent increased. Additionally, increasing reaction temperature led to greater SO2 removal. Meanwhile, the SL-4 and LS-3 sorbents prepared in this study were installed for operation during pilot tests treating the sewage sludge combustion gas generated by a fluidized incinerator in order to compare and evaluate their feasibility for use in industrial applications. The results showed that the reactivity between SO2 and the starting material of the sorbent (Ca(OH)2>CaCO3), as well as the high specific surface area of the sorbent, were confirmed to be critical factors that improved the performance of SO2 removal. Notably, the results confirmed that both fine PM (?1?m) and heavy metals were simultaneously removed with increasing efficiency over the time of operation.
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Pyrrolidone carboxylic acid levels or caspase-14 expression in the corneocytes of lesional skin correlates with clinical severity, skin barrier function and lesional inflammation in atopic dermatitis.
J. Dermatol. Sci.
PUBLISHED: 05-07-2014
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Dry skin in atopic dermatitis (AD) mainly results from barrier impairment due to deficiency of ceramide and natural moisturizing factors including pyrrolidone carboxylic acid (PCA) in stratum corneum (SC). Caspase-14 cleaves filaggrin monomers to free amino acids and their derivatives such as PCA, contributing natural moisturizing factors. Cytokines in the corneocytes represent cutaneous inflammation severity of AD patients.
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Treatment outcome of localized prostate cancer by 70 Gy hypofractionated intensity-modulated radiotherapy with a customized rectal balloon.
Radiat Oncol J
PUBLISHED: 05-02-2014
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We aimed to analyze the treatment outcome and long-term toxicity of 70 Gy hypofractionated intensity-modulated radiotherapy (IMRT) for localized prostate cancer using a customized rectal balloon.
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High crystalline dithienosilole-cored small molecule semiconductor for ambipolar transistor and nonvolatile memory.
ACS Appl Mater Interfaces
PUBLISHED: 04-18-2014
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We characterized the electrical properties of a field-effect transistor (FET) and a nonvolatile memory device based on a solution-processable low bandgap small molecule, Si1TDPP-EE-C6. The small molecule consisted of electron-rich thiophene-dithienosilole-thiophene (Si1T) units and electron-deficient diketopyrrolopyrrole (DPP) units. The as-spun Si1TDPP-EE-C6 FET device exhibited ambipolar transport properties with a hole mobility of 7.3×10(-5) cm2/(Vs) and an electron mobility of 1.6×10(-5) cm2/(Vs). Thermal annealing at 110 °C led to a significant increase in carrier mobility, with hole and electron mobilities of 3.7×10(-3) and 5.1×10(-4) cm2/(Vs), respectively. This improvement is strongly correlated with the increased film crystallinity and reduced ?-? intermolecular stacking distance upon thermal annealing, revealed by grazing incidence X-ray diffraction (GIXD) and atomic force microscopy (AFM) measurements. In addition, nonvolatile memory devices based on Si1TDPP-EE-C6 were successfully fabricated by incorporating Au nanoparticles (AuNPs) as charge trapping sites at the interface between the silicon oxide (SiO2) and cross-linked poly(4-vinylphenol) (cPVP) dielectrics. The device exhibited reliable nonvolatile memory characteristics, including a wide memory window of 98 V, a high on/off-current ratio of 1×10(3), and good electrical reliability. Overall, we demonstrate that donor-acceptor-type small molecules are a potentially important class of materials for ambipolar FETs and nonvolatile memory applications.
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Evaluation of PCR-Reverse Blot Hybridization Assay, REBA Sepsis-ID Test, for Simultaneous Identification of Bacterial Pathogens and mecA and van Genes from Blood Culture Bottles.
Ann Lab Med
PUBLISHED: 03-17-2014
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The aim of this study was to evaluate a newly developed PCR-based reverse blot hybridization assay (PCR-REBA), REBA Sepsis-ID (M&D, Wonju, Korea), to rapidly detect the presence of bacteremia and antimicrobial resistance gene in blood culture samples.
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Evaluation of the INNOVANCE PFA P2Y assay and its association with CYP2C19 genotypes.
Platelets
PUBLISHED: 03-13-2014
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Abstract The purpose of this study was to evaluate associations between INNOVANCE PFA P2Y (PFA P2Y) test results and CYP2C19 genotypes and provide baseline data for PFA P2Y testing to establish a therapeutic monitoring strategy for clopidogrel. A total of 75 new patients with acute coronary syndrome with planned percutaneous coronary intervention were enrolled between June 2012 and September 2012. All patients received clopidogrel at an initial loading dose of 600?mg followed by a 75-mg daily maintenance dose. Blood samples were obtained on the third morning after clopidogrel loading. PFA P2Y, VerifyNow P2Y12 and VASP assays were used to determine platelet inhibition due to clopidogrel, and the Verigene CYP2C19 test was used for CYP2C19 genotyping. The genotype frequency of 75 patients was as follows: CYP2C19 *1/*1 (wild type), 28 (37.3%); *1/*2, 31 (41.3%); *1/*3, 4 (5.3%); *2/*2, 5 (6.7%); *2/*3, 5 (6.7%); *1/*17, 1 (1.3%); and *2/*17, 1 (1.3%). Classified according to CYP2C19 genotypes, there were 29 (38.7%) extensive metabolizers (EM) or ultra rapid metabolizers (UM), 35 (46.7%) intermediate metabolizers (IM), and 10 (13.3%) poor metabolizers (PM). Median (interquartile range) PFA P2Y closure times (seconds) were 119 (101-260), 300 (130-300) and 300 (300-300) in the PM, IM and EM or UM groups, respectively (p??0.05). Compared with non-carriers, carriers of reduced function CYP2C19 alleles tended to have higher platelet reactivity after clopidogrel treatment. The cut-off for PM versus other groups (IM and EM or UM) was ?141 seconds (AUC 0.704, sensitivity 70%, specificity 76.6%) on the ROC curve. A statistically significant correlation between PFA P2Y (seconds) and VerifyNow (PRU) was found (??=?-0.47, p?
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Bioleaching of arsenic from highly contaminated mine tailings using Acidithiobacillus thiooxidans.
J. Environ. Manage.
PUBLISHED: 01-22-2014
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The behavior of arsenic (As) bioleaching from mine tailings containing high amount of As (ca. 34,000 mg/kg) was investigated using Acidithiobacillus thiooxidans to get an insight on the optimal conditions that would be applied to practical heap and/or tank bioleaching tests. Initial pH (1.8-2.2), temperature (25-40 °C), and solid concentration (0.5-4.0%) were employed as experimental parameters. Complementary characterization experiments (e.g., XRD, SEM-EDS, electrophoretic mobility, cell density, and sulfate production) were also carried out to better understand the mechanism of As bioleaching. The results showed that final As leaching efficiency was similar regardless of initial pH. However, greater initial As leaching rate was observed at initial pH 1.8 than other conditions, which could be attributed to greater initial cell attachment to mine tailings. Unlike the trend observed when varying the initial pH, the final As leaching efficiency varied with the changes in temperature and solid concentration. Specifically, As leaching efficiency tended to decrease with increasing temperature due to the decrease in the bacterial growth rate at higher temperature. Meanwhile, As leaching efficiency tended to increase with decreasing solid concentration. The results for jarosite contents in mine tailings residue after bioleaching revealed that much greater amount of the jarosite was formed during the bioleaching reaction at higher solid concentration, suggesting that the coverage of the surface of the mine tailings by jarosite and/or the co-precipitation of the leached As with jarosite could be a dominant factor reducing As leaching efficiency.
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Influence of sulfate and phosphate on the deposition of plasmid DNA on silica and alumina-coated surfaces.
Colloids Surf B Biointerfaces
PUBLISHED: 01-09-2014
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The influence of sulfate and phosphate on the deposition kinetics of plasmid DNA on solid surfaces was examined at a constant 300mM ionic strength in both NaCl-Na2SO4 and NaCl-NaH2PO4-Na2HPO4 mixing solutions with varied sulfate and phosphate concentrations at pH 6.0 by utilizing a quartz crystal microbalance with dissipation (QCM-D). Two representative solid surfaces, both silica and alumina-coated surfaces, were concerned in this study. To better understand the effects of sulfate and phosphate on plasmid DNA deposition, QCM-D data were complemented by diffusion coefficients and zeta potentials of DNA as a function of examined solution conditions. The presence of sulfate and phosphate in solutions decreased the deposition efficiencies of plasmid DNA on both silica and alumina-coated surfaces. Moreover, the deposition efficiencies decreased with increasing concentrations of sulfate/phosphate. With sulfate/phosphate ions present in solutions, the deposition kinetics of plasmid DNA on both silica and alumina-coated surfaces were mainly controlled by classic Derjaguin-Landau-Verwey-Overbeek (DLVO) interactions.
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Quantitative ultrasound characterization of tumor cell death: ultrasound-stimulated microbubbles for radiation enhancement.
PLoS ONE
PUBLISHED: 01-01-2014
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The aim of this study was to assess the efficacy of quantitative ultrasound imaging in characterizing cancer cell death caused by enhanced radiation treatments. This investigation focused on developing this ultrasound modality as an imaging-based non-invasive method that can be used to monitor therapeutic ultrasound and radiation effects. High-frequency (25 MHz) ultrasound was used to image tumor responses caused by ultrasound-stimulated microbubbles in combination with radiation. Human prostate xenografts grown in severe combined immunodeficiency (SCID) mice were treated using 8, 80, or 1000 µL/kg of microbubbles stimulated with ultrasound at 250, 570, or 750 kPa, and exposed to 0, 2, or 8 Gy of radiation. Tumors were imaged prior to treatment and 24 hours after treatment. Spectral analysis of images acquired from treated tumors revealed overall increases in ultrasound backscatter intensity and the spectral intercept parameter. The increase in backscatter intensity compared to the control ranged from 1.9±1.6 dB for the clinical imaging dose of microbubbles (8 µL/kg, 250 kPa, 2 Gy) to 7.0±4.1 dB for the most extreme treatment condition (1000 µL/kg, 750 kPa, 8 Gy). In parallel, in situ end-labelling (ISEL) staining, ceramide, and cyclophilin A staining demonstrated increases in cell death due to DNA fragmentation, ceramide-mediated apoptosis, and release of cyclophilin A as a result of cell membrane permeabilization, respectively. Quantitative ultrasound results indicated changes that paralleled increases in cell death observed from histology analyses supporting its use for non-invasive monitoring of cancer treatment outcomes.
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Nuclear and chloroplast diversity and phenotypic distribution of rice (Oryza sativa L.) germplasm from the democratic people's republic of Korea (DPRK; North Korea).
Rice (N Y)
PUBLISHED: 01-01-2014
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Rice accounts for 43% of staple food production in the Democratic People's Republic of Korea (DPRK). The most widely planted rice varieties were developed from a limited number of ancestral lines that were repeatedly used as parents in breeding programs. However, detailed pedigrees are not publicly available and little is known about the genetic, phenotypic, and geographical variation of DPRK varieties.
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Real-time PCR TaqMan assay for rapid screening of bloodstream infection.
Ann. Clin. Microbiol. Antimicrob.
PUBLISHED: 01-01-2014
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Sepsis is one of the main causes of mortality and morbidity. The rapid detection of pathogens in blood of septic patients is essential for adequate antimicrobial therapy and better prognosis. This study aimed to accelerate the detection and discrimination of Gram-positive (GP) and Gram-negative (GN) bacteria and Candida species in blood culture samples by molecular methods.
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Effect of carbon nanotubes on the transport and retention of bacteria in saturated porous media.
Environ. Sci. Technol.
PUBLISHED: 09-30-2013
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This study investigated the influence of carbon nanotubes (CNTs) on the transport and retention behaviors of bacteria (E. coli) in packed porous media at both low and high ionic strength in NaCl and CaCl2 solutions. At low ionic strengths (5 mM NaCl and 0.3 mM CaCl2), both breakthrough curves and retained profiles of bacteria with CNTs (both 5 and 10 mg L(-1)) were equivalent to those without CNTs, indicating the presence of CNTs did not affect the transport and retention of E. coli at low ionic strengths. The results were supported by those from cell characterization tests (i.e., viability, surface properties, sizes), which showed no significant difference between with and without CNTs. In contrast, breakthrough curves of bacteria with CNTs were lower than those without CNTs at high ionic strengths (25 mM NaCl and 1.2 mM CaCl2), suggesting that the presence of CNTs decreased cell transport at high ionic strengths. The enhanced bacterial deposition in the presence of CNTs was mainly observed at segments near the column inlet, leading to much steeper retained profiles relative to those without CNTs. Additional transport experiments conducted with sand columns predeposited with CNTs revealed that the codeposition of bacteria with CNTs, as well as the deposition of the cell-CNTs cluster formed in cell suspension due to cell bridging effect, largely contributed to the increased deposition of bacteria at high ionic strengths in porous media.
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Coherent X-ray scattering beamline at port 9C of Pohang Light Source II.
J Synchrotron Radiat
PUBLISHED: 07-17-2013
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The coherent X-ray scattering beamline at the 9C port of the upgraded Pohang Light Source (PLS-II) at Pohang Accelerator Laboratory in Korea is introduced. This beamline provides X-rays of 5-20?keV, and targets coherent X-ray experiments such as coherent diffraction imaging and X-ray photon correlation spectroscopy. The main parameters of the beamline are summarized, and some preliminary experimental results are described.
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Core-shell strain structure of zeolite microcrystals.
Nat Mater
PUBLISHED: 05-23-2013
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Zeolites are crystalline aluminosilicate minerals featuring a network of 0.3-1.5-nm-wide pores, used in industry as catalysts for hydrocarbon interconversion, ion exchangers, molecular sieves and adsorbents. For improved applications, it is highly useful to study the distribution of internal local strains because they sensitively affect the rates of adsorption and diffusion of guest molecules within zeolites. Here, we report the observation of an unusual triangular deformation field distribution in ZSM-5 zeolites by coherent X-ray diffraction imaging, showing the presence of a strain within the crystal arising from the heterogeneous core-shell structure, which is supported by finite element model calculation and confirmed by fluorescence measurement. The shell is composed of H-ZSM-5 with intrinsic negative thermal expansion whereas the core exhibits a different thermal expansion behaviour due to the presence of organic template residues, which usually remain when the starting materials are insufficiently calcined. Engineering such strain effects could have a major impact on the design of future catalysts.
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Comparison of the AdvanSure HBV real-time PCR test with three other HBV DNA quantification assays.
Ann. Clin. Lab. Sci.
PUBLISHED: 05-23-2013
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We compared the AdvanSure hepatitis B virus real-time polymerase chain reaction (AdvanSure HBV) kit with three other HBV DNA quantification assays and evaluated its performance.
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Cotransport of titanium dioxide and fullerene nanoparticles in saturated porous media.
Environ. Sci. Technol.
PUBLISHED: 05-23-2013
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This study investigated the cotransport of titanium dioxide nanoparticles (nTiO2) and fullerene nanoparticles (nC60), two of the most widely utilized nanoparticles, in saturated quartz sand under a series of ionic strengths in NaCl solutions (0.1-10 mM) at both pH 5 and 7. Under all examined ionic strengths at pH 5, both breakthrough curves and retained profiles of nTiO2 in the copresence of nC60 were similar to those without nC60, indicating that nC60 nanoparticles copresent in suspensions did not significantly affect the transport and retention of nTiO2 in quartz sand at pH 5. In contrast, under all examined ionic strengths at pH 7, the breakthrough curves of nTiO2 in the copresence of nC60 in suspensions were higher and the retained profiles were lower than those without nC60, which demonstrated that the presence of nC60 in suspensions increased the rate of transport (decreased retention) of nTiO2 in quartz sand at pH 7. Competition of deposition sites on quartz sand surfaces by the copresence of nC60 was found to contribute to the increased nTiO2 transport at pH 7. Under all examined ionic strength conditions at both pH 5 and 7, the breakthrough curves of nC60 were reduced in the copresence of nTiO2, and the corresponding retained profiles were higher than those without nTiO2, indicating that the presence of nTiO2 decreased the transport of nC60 in quartz sand. Co-deposition of nC60 with nTiO2 in the form of nTiO2-nC60 clusters as well as the deposition of nC60 onto previously deposited nTiO2 were responsible for the increased nC60 deposition in the presence of nTiO2 at pH 5, whereas deposition of nC60 onto surfaces of predeposited nTiO2 was found to be responsible for the increased nC60 deposition at pH 7.
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Impact of genetic abnormalities on the prognoses and clinical parameters of patients with multiple myeloma.
Ann Lab Med
PUBLISHED: 03-18-2013
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We reviewed patients with multiple myeloma (MM) in order to assess the incidence of genetic abnormalities and their associations with clinical parameters, risk groups, and prognosis.
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Enteral nutritional intake in adult korean intensive care patients.
Am. J. Crit. Care
PUBLISHED: 03-05-2013
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Nutritional support is important for maximizing clinical outcomes in critically ill patients, but enteral nutritional intake is often inadequate.
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Effects of biophysical parameters in enhancing radiation responses of prostate tumors with ultrasound-stimulated microbubbles.
Ultrasound Med Biol
PUBLISHED: 01-18-2013
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We show here that ultrasound-stimulated microbubbles can enhance cell death within tumors when combined with radiation. The aim of this study was to investigate how different ultrasound parameters, different microbubble concentrations and different radiation doses interact to enhance cell death. Prostate xenograft tumors (PC-3) in severe combined immunodeficiency mice were subjected to ultrasound treatment at various peak negative pressures (250, 570 and 750 kPa) at a center frequency of 500 kHz, different microbubble concentrations (8, 80 and 1000 ?L/kg) and different radiation doses (0, 2 and 8 Gy). Twenty-four hours after treatment, tumors were excised and assessed for cell death. Histologic analyses revealed that increases in radiation dose, microbubble concentration and ultrasound pressure promoted apoptotic cell death and disruption within tumors by as much as 21%, 30% and 43%, respectively. Comparable increases in ceramide, a cell death mediator, were identified using immunohistochemistry. We also show here that even clinically used microbubble concentrations combined with ultrasound can induce significant enhancement of cell death.
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Influence of sulfate on the transport of bacteria in quartz sand.
Colloids Surf B Biointerfaces
PUBLISHED: 01-10-2013
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The influence of sulfate on the transport of bacteria in packed quartz sand was examined at a constant 25mM ionic strength with the sulfate concentration progressively increased from 0 to 20mM at pH 6.0. Two representative cell types, Escherichia coli BL21 (Gram-negative) and Bacillus subtilis (Gram-positive), were used to determine the effect of sulfate on cell transport behavior. For both examined cell types, the breakthrough plateaus in the presence of sulfate in suspensions were higher and the corresponding retained profiles were lower than those without sulfate ions, indicating that the presence of sulfate in suspensions increased cell transport in packed quartz sand regardless of the examined cell types (Gram-positive or Gram-negative). Moreover, the enhancement of bacteria transport induced by the presence of sulfate was more pronounced with increasing sulfate concentration from 5 to 20mM. In contrast with the results for EPS-present bacteria, the presence of sulfate in solutions did not change the transport behavior for EPS-removed cells. The zeta potentials of EPS-present cells with sulfate were found to be more negative relative to those without sulfate in suspensions, whereas, the zeta potentials for EPS-removed cells in the presence of sulfate were similar as those without sulfate. We proposed that sulfate could interact with EPS on cell surfaces and thus negatively increased the zeta potentials of bacteria, contributing to the increased transport in the presence of sulfate in suspensions.
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Bactericidal mechanisms of Ag?O/TNBs under both dark and light conditions.
Water Res.
PUBLISHED: 01-02-2013
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Ag(2)O/TNBs were fabricated by depositing Ag(2)O nanoparticles on the surface of TiO(2) nanobelts (TNBs). The disinfection activities of Ag(2)O/TNBs on two representative bacterial types: Gram-negative Escherichia coli ATCC15597 and Gram-positive Bacillus subtilis, were examined under both dark and visible light conditions. Ag(2)O/TNBs exhibited stronger bactericidal activities than Ag(2)O nanoparticles and TNBs under both dark and light conditions. For both cell types, disinfection effects of Ag(2)O/TNBs were greater under light conditions relative to those under dark conditions. The bactericidal mechanisms of Ag(2)O/TNBs under both dark and light conditions were explored. Ag(+) ions released from Ag(2)O/TNBs did not contribute to the bactericidal activity of Ag(2)O/TNBs under dark conditions, whereas the released Ag(+) ions showed bactericidal activity under visible light irradiation conditions. Active species (H(2)O(2), O(2)(-)·, and e(-)) generated by Ag(2)O/TNBs played important roles in the disinfection processes under both dark and visible light irradiation conditions. Without the presence of active species, the direct contact of Ag(2)O/TNBs with bacterial cells had no bactericidal effect.
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Vpr-binding protein antagonizes p53-mediated transcription via direct interaction with H3 tail.
Mol. Cell. Biol.
PUBLISHED: 12-19-2011
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HIV-1 Vpr-binding protein (VprBP) has been implicated in the regulation of both DNA replication and cell cycle progression, but its precise role remains unclear. Here we report that VprBP regulates the p53-induced transcription and apoptotic pathway. VprBP is recruited to p53-responsive promoters and suppresses p53 transactivation in the absence of stress stimuli. To maintain target promoters in an inactive state, VprBP stably binds to nucleosomes by recognizing unacetylated H3 tails. Promoter-localized deacetylation of H3 tails is a prerequisite for VprBP to tether and act as a bona fide inhibitor at p53 target genes. VprBP knockdown leads to activation of p53 target genes and causes an increase in DNA damage-induced apoptosis. Moreover, phosphorylation of VprBP at serine 895 impairs the ability of VprBP to bind H3 tails and to repress p53 transactivation. Our results thus reveal a new role for VprBP in regulation of the p53 signaling pathway, as well as molecular mechanisms of cancer development related to VprBP misregulation.
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Effects of Schisandra chinensis extract on the contractility of corpus cavernosal smooth muscle (CSM) and Ca2+ homeostasis in CSM cells.
BJU Int.
PUBLISHED: 09-27-2011
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Whats known on the subject? And what does the study add? Schisandra chinensis extract (SCE) has been known to have relaxative effects on penile smooth muscle. A recent study showed that SCE could enhance slidenafil citrate-induced relaxation of penile corpus cavernosum. The current study investigated the mechanism of action of SCE and its constituents on corporal smooth muscle cells. And this study shows that SCE induced relaxation of CSM primarily through an endothelium independent pathway and the relaxation effects of SCE on corporal smooth muscle are, in part, due to the activation of K(+) channels and inhibition of TRPC6 channels, resulting in decreased [Ca(2+)].
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Helical silicon/silicon oxide core-shell anodes grown onto the surface of bulk silicon.
Nano Lett.
PUBLISHED: 09-16-2011
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We demonstrate a simple route for preparing Si/SiO(x) urchin-like structures in which Si/SiO(x) core-shell nanocoils protruded out from the surface of bulk Si, via high-temperature annealing of Pt-decorated Si powders. The carbon-coated urchin-like anodes with micro- and nanostructured composite exhibit a significantly improved electrochemical performance with a high specific capacity of 1600 mAh/g and a superior cycling performance of 70 cycles at a rate of 0.2 C due to the nanocoil conformation and SiO(x) buffer layer. More importantly, the composite results in a significantly enhanced the volumetric capacity with ?3780 mAh/cc, compared to bulk Si (?2720 mAh/cc) after fully lithiation to 0 V.
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Deposition kinetics of MS2 bacteriophages on clay mineral surfaces.
Colloids Surf B Biointerfaces
PUBLISHED: 08-31-2011
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The deposition of bacteriophage MS2 on bare and clay-coated silica surfaces was examined in both monovalent (NaCl) and divalent (CaCl(2) and MgCl(2)) solutions under a wide range of environmentally relevant ionic strength and pH conditions by utilizing a quartz crystal microbalance with dissipation (QCM-D). Two types of clay, bentonite and kaolinite, were concerned in this study. To better understand MS2 deposition mechanisms, QCM-D data were complemented by zeta potentials measurements and Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction forces calculation. In both monovalent and divalent solutions, deposition efficiencies of MS2 increased with increasing ionic strength both on bare and clay-coated surfaces, which agreed with the trends of interaction forces between MS2 and solid surface and thus was consistent with DLVO theory. The presence of divalent ions (Ca(2+) and Mg(2+)) in solutions greatly increased virus deposition on both silica and clay deposited surfaces. Coating silica surfaces with clay minerals, either kaolinite or bentonite, could significantly increase MS2 deposition.
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Selective requirement of H2B N-Terminal tail for p14ARF-induced chromatin silencing.
Nucleic Acids Res.
PUBLISHED: 08-16-2011
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The N-terminal tail of histone H2B is believed to be involved in gene silencing, but how it exerts its function remains elusive. Here, we report the biochemical characterization of p14ARF tumor suppressor as a transcriptional repressor that selectively recognizes the unacetylated H2B tails on nucleosomes. The p14ARF-H2B tail interaction is functional, as the antagonistic effect of p14ARF on chromatin transcription is lost upon deletion or acetylation of H2B tails. Gene expression profiling and chromatin immunoprecipitation studies emphasize the significance of H2B deacetylation and p14ARF recruitment in establishing a repressive environment over the cell cycle regulatory genes. Moreover, HDAC1-mediated H2B deacetylation, especially at K20, constitutes an essential step in tethering p14ARF near target promoters. Our results thus reveal a hitherto unknown role of p14ARF in the regulation of chromatin transcription, as well as molecular mechanisms governing the repressive action of p14ARF.
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Influence of humic acid on the transport behavior of bacteria in quartz sand.
Colloids Surf B Biointerfaces
PUBLISHED: 07-17-2011
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The significance of natural organic matter (NOM) on the transport of bacteria in packed porous media (quartz sand) was examined in both NaCl and CaCl(2)-NaCl mixing solutions at pH 6.0. Three representative cell types (with EPS), Rhodococcus sp. QL2 (Gram-positive, non-motile), Escherichia coli BL21 (Gram-negative, non-motile), and E. coli C3000 (Gram-negative, motile), were utilized to systematically determine the influence of NOM (Suwannee River humic acid (SRHA)) on cell transport behavior. To investigate the significance of SRHA on transport of bacteria without EPS on cell surfaces, experiments for treated cells with the removal of EPS from cell surfaces were also performed. The breakthrough plateaus for all examined bacteria with the presence of SRHA (1 mg L(-1)) in solutions were higher than those with the absence of SRHA under all examined conditions, indicating that the presence of SRHA in solutions enhanced cell transport regardless of cell types (Gram-negative or Gram-positive), motility (non-motile or motile), presence or absence of EPS on cell surfaces, and solution chemistry (ionic strength and ion valence). Zeta potentials for bacteria and quartz sand with the presence of SRHA were similar as those without SRHA present in solutions, suggesting that SRHA did not alter the surface charge of bacteria or sand, thus the enhanced cell transport by SRHA was not likely driven by alteration in the surface charge of either cell or quartz sand. SRHA pre-equilibration experiments demonstrated that the site competition by a portion of SRHA and the repelling deposition by suspended SRHA contributed to the decreased cell deposition observed with the presence of SRHA in bacteria suspension.
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Histone variant H3.3 stimulates HSP70 transcription through cooperation with HP1?.
Nucleic Acids Res.
PUBLISHED: 07-08-2011
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Histone variant H3.3 and heterochromatin protein 1? (HP1?) are two functional components of chromatin with role in gene transcription. However, the regulations of their dynamics during transcriptional activation and the molecular mechanisms underlying their actions remain poorly understood. Here, we provide evidence that heat shock-induced transcription of the human HSP70 gene is regulated via the coordinated and interdependent action of H3.3 and HP1?. H3.3 and HP1? are rapidly co-enriched at the human HSP70 promoters upon heat shock in a manner that closely parallels the initiation of transcription. Knockdown of H3.3 prevents the stable recruitment of HP1?, inhibits active histone modifications, and attenuates HSP70 promoter activity. Likewise, knockdown of HP1? leads to the decreased levels of H3.3 in the promoter regions and the repression of HSP70 genes. HP1? selectively recognizes particular modification states of H3.3 in the nucleosome for its action. Moreover, HP1? is overexpressed in three representative cancer cell lines, and its knockdown leads to reduction in HSP70 gene transcription and inhibition of cancer cell proliferation. We conclude that the physical and functional interactions between H3.3 and HP1? make a unique contribution to acute HSP70 transcription and cancer development related to the misregulation of this transcription event.
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p53 requires an intact C-terminal domain for DNA binding and transactivation.
J. Mol. Biol.
PUBLISHED: 05-04-2011
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The tumor suppressor p53 plays a critical role in mediating cellular response to a wide range of environmental stresses. p53 regulates these processes mainly by acting as a short-lived DNA binding protein that stimulates transcription from numerous genes involved in cell cycle arrest, programmed cell death, and other processes. To investigate the importance of the C-terminal domain of p53, we generated a series of deletion and point mutations in this region and analyzed their effects on p53 transcription activity. Our results show that C-terminal deletion and point mutations at K320 and K382 abolish p53-mediated transcription in the context of DNA or chromatin. This defect is specific for DNA molecules because inactive mutants fail to bind a consensus p53 response element in both free DNA and nucleosomes. Chromatin immunoprecipitation assays further substantiate the importance of the p53 C-terminal domain for the targeted localization of p53 and the concomitant recruitment of p300 onto p53-responsive genes. Moreover, a synthetic peptide comprising the last 30 amino acids of p53 interacts with the N-terminal and C-terminal domains of p53 and antagonizes p53-dependent transcription. Taken together, our data reveal a functional requirement for the p53 C-terminal domain in p53 transactivation and support a working model in which the C-terminus serves as a positive regulator for N-terminal activation and central DNA binding domains.
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A topical Chinese herbal mixture improves epidermal permeability barrier function in normal murine skin.
Exp. Dermatol.
PUBLISHED: 02-18-2011
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Chinese herbal medicine (CHM) has been shown to have beneficial effects for both skin disorders with barrier abnormality and as skin care ingredients. Yet, how CHM exerts their benefits is unclear. As most, if not all, inflammatory dermatoses are accompanied by abnormal permeability barrier function, we assessed the effects of topical CHM extracts on epidermal permeability barrier function and their potential mechanisms. Topical CHM accelerated barrier recovery following acute barrier disruption. Epidermal lipid content and mRNA expression of fatty acid and ceramide synthetic enzymes increased following topical CHM treatment in addition to mRNA levels for the epidermal glucosylceramide transport protein, ATP-binding cassette A12. Likewise, CHM extract increased mRNA expression of antimicrobial peptides both in vivo and in vitro. These results demonstrate that the topical CHM extract enhances epidermal permeability barrier function, suggesting that topical CHM could provide an alternative regimen for the prevention/treatment of inflammatory dermatoses accompanied by barrier abnormalities.
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Changes in nutritional status in ICU patients receiving enteral tube feeding: a prospective descriptive study.
Intensive Crit Care Nurs
PUBLISHED: 02-01-2011
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This study aimed to assess the changes in nutritional status in Korean ICU patients receiving enteral feeding, and to understand the contribution of baseline nutritional status and energy intake to nutritional changes during the ICU stay.
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Influence of natural organic matter on the deposition kinetics of extracellular polymeric substances (EPS) on silica.
Colloids Surf B Biointerfaces
PUBLISHED: 01-24-2011
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The influence of humic acid and alginate, two major components of natural organic matter (NOM), on deposition kinetics of extracellular polymeric substances (EPS) on silica was examined in both NaCl and CaCl(2) solutions over a wide range of environmentally relevant ionic strengths utilizing a quartz crystal microbalance with dissipation. Deposition kinetics of both soluble EPS and bound EPS extracted from four bacterial strains with different characteristics was investigated. EPS deposition on humic acid-coated silica surfaces was found to be much lower than that on bare silica surfaces under all examined conditions. In contrast, pre-coating the silica surfaces with alginate enhanced EPS deposition in both NaCl and CaCl(2) solutions. More repulsive electrostatic interaction between EPS and surface contributed to the reduced EPS deposition on humic acid-coated silica surface. The trapping effect induced by the rough alginate layer resulted in the greater EPS deposition on alginate-coated surfaces in NaCl solutions, whereas surface heterogeneities on alginate layer facilitated favorable interactions with EPS in CaCl(2) solutions. The presence of dissolved background humic acid and alginate in solutions both significantly retarded EPS deposition on silica surfaces due to the greater steric and electrostatics repulsion.
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Differences of urease activity and expression of associated genes according to gastric topography.
Helicobacter
PUBLISHED: 01-19-2011
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We hypothesize that pH difference between acid-secreting corpus and non-secreting antrum might influence the activity of H. pyloris urease and/or related genes. We therefore measured urease activity and the expression of amiE whose encoded protein that hydrolyzes short-chain amides to produce ammonia.
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Large scale chiral chromatography for the separation of an enantiomer to accelerate drug development.
Chirality
PUBLISHED: 01-06-2011
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There are several approaches to produce enantiomerically pure drug substances, such as recrystallization, catalytic process (ligand and enzyme), indirect chromatographic resolution, and direct chromatographic resolution. However, the use of preparative chromatography with chiral stationary phases seems to be most effective for early phase projects, where the time and resources on the developments need to be minimized to get the drug candidates into the clinical studies. We showed that by following a well-defined process, chiral chromatography can be easily scaled up from an analytical system to a pilot plant system. We also used the results from a multicolumn continuous chromatography (MCC) study to conclude that MCC can be a cost-effective production method for chiral manufacturing.
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Implications of cation exchange on clay release and colloid-facilitated transport in porous media.
J. Environ. Qual.
PUBLISHED: 09-07-2010
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Column experiments were conducted to study chemical factors that influence the release of clay (kaolinite and quartz minerals) from saturated Ottawa sand of different sizes (710,360, and 240 microm). A relatively minor enhancement of clay release occurred when the pH was increased (5.8 to 10) or the ionic strength (IS) was decreased to deionized (DI) water. In contrast, clay release was dramatically enhanced when monovalent Na+ was exchanged for multivalent cations (e.g., Ca2+ and Mg2+) on the clay and sand and then the solution IS was reduced to DI water. This solution chemistry sequence decreased the adhesive force acting on the clay as a result of an increase in the magnitude of the clay and sand zeta potential with cation exchange, and expansion of the double layer thickness with a decrease in IS to DI water. The amount of clay release was directly dependent on the Na+ concentration of the exchanging solution and on the initial clay content of the sand (0.026-0.054% of the total mass). These results clearly demonstrated the importance of the order and magnitude of the solution chemistry sequence on clay release. Column results and scanning electron microscope (SEM) images also indicated that the clay was reversibly retained on the sand, despite predictions of irreversible interaction in the primary minimum. One plausible explanation is that adsorbed cations increased the separation distance between the clay-solid interfaces as a result of repulsive hydration forces. A cleaning procedure was subsequently developed to remove clay via cation exchange and IS reduction; SEM images demonstrated the effectiveness of this approach. The transport of Cu2+ was then shown to be dramatically enhanced by an order of magnitude in peak concentration by adsorption on clays that were released following cation exchange and IS reduction.
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Transport and retention of fullerene nanoparticles in natural soils.
J. Environ. Qual.
PUBLISHED: 09-07-2010
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Commercial production and use of fullerene (C60) nanomaterials will inevitably lead to their release into the environment, where knowledge of C60 fate and transport is limited. In this study, a series of one-dimensional column experiments was conducted to assess the transport and retention of nanoscale fullerene aggregates (nC60) in water-saturated soils. Under the experimental conditions, complete retention of nC60 was observed in columns (2.5 cm inside diameter x 11 cm length) packed with Appling or Webster soil, which contain 0.75 and 3.33% organic carbon by weight, respectively. When the volume of aqueous nC60 suspension (approximately 4.5 mg L(-1)) applied to Appling soil was increased from 5 to 65 pore volumes, the travel distance increased from 3 to 8 cm, and the retention capacity approached a limiting value of 130 microg g(-1), although nC60 was not detected in the column effluent. The addition of 20 mg C L(-1) Suwannee River humic acid to the influent suspension increased the nC60 transport in Appling soil but did not resul in breakthrough. Attempts to simulate the experimental data using clean-bed filtration theory were not satisfactory, yielding retention profiles that failed to match observed data. Subsequent incorporation of a limiting retention capacity expression into the mathematical model resulted in accurate predictions of the measured nC60 retention profiles and transport behavior. The sizable retention capacities observed in this study suggest that transport of nC60 is limited in relatively fine-textured soils containing appreciable amounts of clay minerals and organic matter, with substantial accumulation of nC60 aggregates near the point of release.
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Influence of solution chemistry on the deposition and detachment kinetics of RNA on silica surfaces.
Colloids Surf B Biointerfaces
PUBLISHED: 06-22-2010
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The deposition kinetics of RNA extracted from both virus and bacteria on silica surfaces were examined in both monovalent (NaCl) and divalent (CaCl(2)) solutions under a wide range of environmentally relevant ionic strength and pH conditions by utilizing a quartz crystal microbalance with dissipation (QCM-D). To better understand the RNA deposition mechanisms, QCM-D data were complemented by diffusion coefficients and zeta potentials of RNA as a function of examined solution chemistry conditions. Favorable deposition of RNA on poly-l-lysine-coated (positively charged) silica surfaces was governed by the convective-diffusive transport of RNA to the surfaces. The deposition kinetics of RNA on bare silica surfaces were controlled by classic Derjaguin-Landau-Verwey-Overbeek (DLVO) interactions. The presence of divalent cations (Ca(2+)) in solutions greatly enhanced the deposition kinetics of RNA on silica surfaces. Solution pH also affected the deposition behavior of RNA on silica surfaces. Release experiments showed that detachment of RNA from silica surfaces was significant in NaCl solutions, whereas, the deposited RNA on silica surfaces in CaCl(2) solutions was more likely to be irreversible.
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Automated heart-type fatty acid-binding protein assay for the early diagnosis of acute myocardial infarction.
Am. J. Clin. Pathol.
PUBLISHED: 06-17-2010
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We compared an automated quantitative heart-type fatty acid-binding protein (H-FABP) assay with other cardiac-marker assays to examine its usefulness as an early diagnostic marker of acute myocardial infarction (AMI). Serum samples for cardiac troponin T (cTnT), creatine kinase-MB isozyme (CK-MB), myoglobin, and H-FABP were obtained from 64 patients with AMI and 53 patients with other conditions (control group). H-FABP was measured by using 2 immunoassays, the H-FABP enzyme-linked immunosorbent assay (ELISA; Biocheck, Foster City, CA) and the H-FABP latex turbidimetric immunoassay (LTIA; HBI, Anyang, Korea). Sensitivities of assays for cTnT, CK-MB, myoglobin, H-FABP (by ELISA), H-FABP (by LTIA), and electrocardiogram (ECG) for the diagnosis of AMI at hospital admission were 39.1%, 59.4%, 64.1%, 68.7%, 70.3%, and 54.7%, respectively. Specificities of cTnT, CK-MB, myoglobin, H-FABP (by ELISA), H-FABP (by LTIA), and ECG were 98.1%, 71.7%, 81.1%, 77.4%, 90.6%, and 92.5%, respectively. The automated H-FABP (by LTIA) is superior to cTnT, CK-MB, myoglobin, and H-FABP (by ELISA) tests for the diagnosis of AMI in patients admitted within 4 hours from the onset of chest pain.
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Synthesis and characterization of dexamethasone-conjugated linear polyethylenimine as a gene carrier.
J. Cell. Biochem.
PUBLISHED: 06-01-2010
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Linear polyethylenimine (25 kDa, LPEI25k) has been shown to be an effective non-viral gene carrier with higher transfection and lower toxicity than branched polyethylenimine (BPEI) of comparable molecular weight. In this study, dexamethasone was conjugated to LPEI25k to improve the efficiency of gene delivery. Dexamethasone is a synthetic glucocorticoid receptor ligand. Dexamethasone-conjugated LPEI25k (LPEI-Dexa) was evaluated as a gene carrier in various cells. Gel retardation assays showed that LPEI-Dexa completely retarded plasmid DNA (pDNA) at a 0.75:1 weight ratio (LPEI/pDNA). LPEI-Dexa had the highest transfection efficiency at a 2:1 weight ratio (LPEI-Dexa/DNA). At this ratio, the size of the LPEI-Dexa/pDNA complex was approximately 125 nm and the zeta potential was 35 mV. LPEI-Dexa had higher transfection efficiency than LPEI and Lipofectamine 2000. In addition, the cytotoxicity of LPEI-Dexa was much lower than that of BPEI (25 kDa, BPEI25k). In conclusion, LPEI-Dexa has a high transfection efficiency and low toxicity and can therefore be used for non-viral gene delivery.
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Contribution of extracellular polymeric substances on representative gram negative and gram positive bacterial deposition in porous media.
Environ. Sci. Technol.
PUBLISHED: 03-06-2010
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The significance of extracellular polymeric substances (EPS) on cell transport and retained bacteria profiles in packed porous media (quartz sand) was examined by direct comparison of the overall deposition kinetics and retained profiles of untreated bacteria (with EPS) versus those of treated cells (without EPS) from the same cell type. Four representative cell types, Pseudomonas sp. QG6 (gram-negative, motile), mutant Escherichia coli BL21 (gram-negative, nonmotile), Bacillus subtilis (gram-positive, motile), and Rhodococcus sp. QL2 (gram-positive, nonmotile), were employed to systematically determine the influence of EPS on cell transport and deposition behavior. Packed column experiments were conducted for the untreated and treated cells in both NaCl (four ionic strength ranging from 2.5 mM to 20 mM) and CaCl(2) (5 mM) solutions at pH 6.0. The breakthrough plateaus of untreated bacteria were lower than those of treated bacteria for all four cell types under all examined conditions (in both NaCl and CaCl(2) solutions), indicating that the presence of EPS on cell surfaces enhanced cell deposition in porous media regardless of cell type and motility. Retained profiles of both untreated and treated cells for all four cell types deviated from classic filtration theory (log-linear decreases). However, the degree of deviation was greater for all four untreated cells, indicating that the presence of EPS on cell surfaces increased the deviation of retained profiles from classic filtration theory. Elution experiments demonstrated that neither untreated nor treated cells preferentially deposited in secondary energy minima. Furthermore, the release of previously deposited cells in the secondary energy minima did not change the shape of retained cell profiles, indicating that deposition in secondary energy minima did not produce the observed deviations of retained profiles from classic filtration theory.
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Post-prandial lipid levels for assessing target goal achievement in type 2 diabetic patients taking statin.
J. Korean Med. Sci.
PUBLISHED: 02-17-2010
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It is inconvenient to perform serum lipid analysis in fasting state in diabetic patients with drug treatment. In patients with statin treatment and Asian diet, it has not been clearly known whether non-fasting values could be used for the clinical decision making in diabetic patients. In this study, fasting and post-prandial plasma lipid profiles of hospitalized type 2 diabetic patients taking statin, were measured in whom standard diabetic breakfast in traditional Korean style were provided. In repeated-measures ANOVA, there were no significant differences among fasting, post-prandial 2 and 4 hr low-density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol values. When compared to fasting levels, both post-prandial 2 hr and 4 hr LDL cholesterol levels were misclassified as not achieved target goal only in 4% of patients. Post-prandial HDL cholesterol matched with fasting values in women, without exception. In conclusion, the fasting and post-prandial LDL and HDL cholesterol levels are not significantly different each other and can be used in the assessment of achieving target goal in type 2 diabetes taking statin after Korean diet.
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Hysteresis of colloid retention and release in saturated porous media during transients in solution chemistry.
Environ. Sci. Technol.
PUBLISHED: 02-09-2010
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Saturated packed column and micromodel transport studies were conducted to gain insight on mechanisms of colloid retention and release under unfavorable attachment conditions. The initial deposition of colloids in porous media was found to be a strongly coupled process that depended on solution chemistry and pore space geometry. During steady state chemical conditions, colloid deposition was not a readily reversible process, and micromodel photos indicated that colloids were immobilized in the presence of fluid drag. Upon stepwise reduction in eluting solution ionic strength (IS), a sharp release of colloids occurred in each step which indicates that colloid retention depends on a balance of applied (hydrodynamic) and resisting (adhesive) torques which varied with pore space geometry, surface roughness, and interaction energy. When the eluting fluid IS was reduced to deionized water, the final retention locations occurred near grain-grain contacts, and colloid aggregation was sometimes observed in micromodel experiments. Significant amounts of colloid retention hysteresis with IS were observed in the column experiments, and it depended on the porous medium (glass beads compared with sand), the colloid size (1.1 and 0.5 mum), and on the initial deposition IS. These observations were attributed to weak adhesive interactions that depended on the double layer thickness (e.g., the depth of the secondary minimum and/or nanoscale heterogeneity), colloid mass transfer on the solid phase to regions where the torque and force balances were favorable for retention, the number and extent of grain-grain contacts, and surface roughness.
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Comparison of antiplatelet potency of sarpogrelate, aspirin, and beraprost in healthy volunteers according to in-vitro closure time.
Blood Coagul. Fibrinolysis
PUBLISHED: 02-04-2010
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This open-label prospective study compared the antiplatelet potency of sarpogrelate, aspirin, and beraprost in 20 healthy volunteers according to in-vitro closure time. Volunteers were assigned to receive sarpogrelate, aspirin, or beraprost for 14 days, then given 14 days of washout, then switched to another of these medications. We measured in-vitro closure time using a platelet function analyzer with collagen/epinephrine (CEPI). We also measured bleeding time, von Willebrand factor (vWF), D-dimer, high sensitivity C-reactive protein (hs-CRP), and fibrinogen. Baseline parameters were normal in all individuals and were not significantly different among the three groups. In patients who received sarpogrelate, there was no difference in CEPI-closure time at baseline and after 14 days. Aspirin and beraprost significantly prolonged the day 14 CEPI-closure time compared with baseline, from 145 +/- 37 to 259 +/- 41 s (P < 0.0001) and from 134 +/- 37 to 150 +/- 27 s (P = 0.035), respectively. The CEPI-closure time change was greater for aspirin than for beraprost (178 +/- 28 vs. 112 +/- 20%, P < 0.0001). None of the drugs changed the bleeding times of levels of vWF, D-dimer, hs-CRP, and fibrinogen. In conclusion, ingestion of aspirin (100 mg daily) and beraprost (120 microg daily) for 14 days significantly prolonged in-vitro closure time but ingestion of saprogrelate (300 mg daily) for 14 days did not. Aspirin was superior to beraprost in antiplatelet potency, as assessed by in-vitro closure time with CEPI.
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Syndecan-2 regulates cell migration in colon cancer cells through Tiam1-mediated Rac activation.
Biochem. Biophys. Res. Commun.
PUBLISHED: 11-23-2009
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Expression of the cell surface adhesion receptor syndecan-2 is known to be involved in the regulation of cancer cell migration. However, the molecular mechanism of syndecan-2-mediated cell migration remains unknown. Here we report that Rac contributes to the regulation of syndecan-2-mediated cancer cell migration. Overexpression of syndecan-2 enhanced migration and invasion of human colon adenocarcinoma cells Caco-2 and HCT116 cells. In parallel with the increased cell migration/invasion, syndecan-2 overexpression enhanced Rac activity, while dominant negative Rac (RacN17) diminished syndecan-2-mediated increased cancer cell migration. In addition syndecan-2 expression increased membrane localization of Tiam1 and syndecan-2-mediated cell migration/invasion of Caco-2 cells was diminished when Tiam1 levels were knocked-down with small inhibitory RNAs. Furthermore, oligomerization-defective syndecan-2 mutants failed to increase membrane localization of Tiam1, activation of Rac and subsequent cell migration of both Caco-2 and HCT116 cells. Taken together, these results suggest that syndecan-2 regulates cell migration of colon carcinoma cells through Tiam1-dependent Rac activation in colon cancer cells.
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Surface characteristics and adhesion behavior of Escherichia coli O157:H7: role of extracellular macromolecules.
Biomacromolecules
PUBLISHED: 09-15-2009
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Experiments were conducted using enterohemorrhagic Escherichia coli O157:H7 cells to investigate the influence of extracellular macromolecules on cell surface properties and adhesion behavior to quartz sand. Partial removal of the extracellular macromolecules on cells by a proteolytic enzyme (proteinase K) was confirmed using Fourier transform infrared spectroscopy analyses. The proteinase K treated cells exhibited more negative electrophoretic mobility (EPM) at an ionic strength (IS) < or = 1 mM, a slightly lower isoelectric point, and were less hydrophobic as compared to the untreated cells. Potentiometric titration results indicated that the total site concentration (i.e., the total amount of exposed functional groups per cell) on the treated cells was approximately 22% smaller than the untreated cells, while the dissociation constants were almost identical. Analysis of the EPM data using soft particle theory showed that the removal of extracellular macromolecules resulted in polymeric layers outside the cell surface that were less electrophoretically soft. The more negative mobility for the treated cells was likely due to the combined effects of a change in the distribution of functional groups and an increase in the charges per unit volume after enzyme treatment and not just removal of extracellular macromolecules. The proteolytic digestion of extracellular macromolecules led to a significant difference in the cell adhesion to quartz sand. The adhesion behavior for treated cells was consistent with DLVO theory and increased with IS due to less negativity in the EPM. In contrast, the adhesion behavior of untreated cells was much more complex and exhibited a maximum at IS = 1 mM. The treated cells exhibited less adhesion than the untreated cells when the IS < or = 1 mM due to their more negative EPM. However, when the IS > or = 10 mM, a sudden decrease in the removal efficiency was observed only for the untreated cells even through EPM values were similar for both treated and untreated cells. This result suggested that an additional non-DLVO type interaction, electrosteric repulsion, occurred at higher IS (> or =10 mM in this study) for the untreated cells due to the presence of extracellular macromolecules that hindered cell adhesion to the quartz surface. This finding provides important insight into the role of macromolecule-induced E. coli O157:H7 interactions in aquatic environments.
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[Comparison of quantitative results among two automated Rapid Plasma Reagin (RPR) assays and a manual RPR test].
Korean J Lab Med
PUBLISHED: 09-04-2009
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We compared two automated Rapid Plasma Reagin (RPR) assay kits with a manual RPR assay kit to evaluate the possibility of using the two automated RPR assays as an alternative to the manual RPR assay for a quantitative monitoring.
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Prevalence and risk factors for aspirin and clopidogrel resistance in patients with coronary artery disease or ischemic cerebrovascular disease.
Ann. Clin. Lab. Sci.
PUBLISHED: 08-12-2009
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The objective of this study was to identify possible risk factors associated with a lack of response to aspirin and clopidogrel treatments in patients with coronary or cerebral ischemic artery disease. A point-of-care analyzer, VerifyNow (Accumetrics, San Diego, CA), was used to measure adenosine-5-diphosphate and platelet P2YI2 receptor blockage to investigate the responses of a group of 197 patients to aspirin and/ or clopidogrel therapies (aspirin therapy, 178; clopidogrel therapy, 139; both drugs, 144). Of these 197 patients, 135 (68.5%) had coronary artery disease and 72 (31.5%) had ischemic cerebrovascular disease. Aspirin resistance was defined as an ARU (aspirin reaction units) > or =550, and clopidogrel resistance was defined as platelet inhibition <20%. Twenty-five of 178 aspirin users (14.0%) were resistant to aspirin, and 54 of 139 (38.8%) clopidogrel users were resistant to clopidogrel. The data indicate that low hemoglobin (Hb) level in aspirin users and high systolic and diastolic blood pressures in clopidogrel users are significantly related to treatment resistance (p < 0.05). The latter finding is possibly due to the greater adhesiveness and increased aggregability of platelets in hypertensive patients.
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Escherichia coil O157:H7 transport in saturated porous media: role of solution chemistry and surface macromolecules.
Environ. Sci. Technol.
PUBLISHED: 07-17-2009
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The transport and deposition behavior of Escherichia coli O157: H7 was investigated in saturated packed-bed columns and micromodel systems over a range of ionic strength (IS) (1, 10, and 100 mM) and pH (5.8, 8.4, and 9.2) conditions. At a given IS, elevated solution pH resulted in decreased deposition as a result of the increase in the measured zeta potential of the quartz sand. This deposition trend was consistent with predictions from classic Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Conversely, the E. coil O157:H7 deposition was inversely proportionalto IS (1-100 mM) at high pH conditions (8.4 and 9.2), whereas no effect of IS was observed at pH 5.8. This deposition trend was not consistent with DLVO theory, but could be explained by pH-associated electrosteric stabilization. This phenomenon is driven by the pH-dependent protonated state of functional groups on E. coil O157:H7 surface macromolecules and the corresponding conformational state of the bacterial polymers. Results from this study demonstrate that retention of E. coil O157:H7 cells in porous media is a complex process that depends on the solution chemistry, cell-cell interactions, and pore structure. The findings in this study also imply that previous work conducted at lower pH and IS conditions may underestimate E. coli O157:H7 travel distance in higher salt and pH groundwater environments.
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Colorectal cancer cell-derived microvesicles are enriched in cell cycle-related mRNAs that promote proliferation of endothelial cells.
BMC Genomics
PUBLISHED: 06-30-2009
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Various cancer cells, including those of colorectal cancer (CRC), release microvesicles (exosomes) into surrounding tissues and peripheral circulation. These microvesicles can mediate communication between cells and affect various tumor-related processes in their target cells.
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Coupled factors influencing the transport and retention of Cryptosporidium parvum oocysts in saturated porous media.
Water Res.
PUBLISHED: 06-09-2009
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The coupled role of solution ionic strength (IS), hydrodynamic force, and pore structure on the transport and retention of viable Cryptosporidium parvum oocyst was investigated via batch, packed-bed column, and micromodel systems. The experiments were conducted over a wide range of IS (0.1-100 mM), at two Darcy velocities (0.2 and 0.5 cm/min), and in two sands (median diameters of 275 and 710 microm). Overall, the results suggested that oocyst retention was a complex process that was very sensitive to the solution IS, the Darcy velocity, and the grain size. Increasing IS led to enhanced retention of oocysts in the column, which is qualitatively consistent with predictions of Derjaguin-Landau-Verwey-Overbeek theory. Conversely, increasing velocity and grain size resulted in less retention of oocysts in the column due to the difference in the fluid drag force and the rates of mass transfer from the liquid to the solid phase and from high to low velocity regions. Oocyst retention was controlled by a combined role of low velocity regions, weak attractive interactions, and/or steric repulsion. The contribution of each mechanism highly depended on the solution IS. In particular, micromodel observations indicated that enhanced oocyst retention occurred in low velocity regions near grain-grain contacts under highly unfavorable conditions (IS=0.1 mM). Oocyst retention was also found to be influenced by weak attractive interactions (induced by the secondary energy minimum, surface roughness, and/or nanoscale chemical heterogeneity) when the IS=1 mM. Reversible retention of oocysts to the sand in batch and column studies under favorable attachment conditions (IS=100 mM) was attributed to steric repulsion between the oocysts and the sand surface due to the presence of oocyst surface macromolecules. Comparison of experimental observations and theoretical predictions from classic filtration theory further supported the presence of this weak interaction due to steric repulsion.
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Requirement of histone methyltransferase SMYD3 for estrogen receptor-mediated transcription.
J. Biol. Chem.
PUBLISHED: 06-09-2009
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SMYD3 is a SET domain-containing protein with histone methyltransferase activity on histone H3-K4. Recent studies showed that SMYD3 is frequently overexpressed in different types of cancer cells, but how SMYD3 regulates the development and progression of these malignancies remains unknown. Here, we report the previously unrecognized role of SMYD3 in estrogen receptor (ER)-mediated transcription via its histone methyltransferase activity. We demonstrate that SMYD3 functions as a coactivator of ERalpha and potentiates ERalpha activity in response to ligand. SMYD3 directly interacts with the ligand binding domain of ER and is recruited to the proximal promoter regions of ER target genes upon gene induction. Importantly, our chromatin immunoprecipitation analyses provide compelling evidence that SMYD3 is responsible for the accumulation of di- and trimethylation of H3-K4 at the induced ER target genes. Furthermore, RNA interference-directed down-regulation of SMYD3 reveals that SMYD3 is required for ER-regulated gene transcription in estrogen signaling pathway. Thus, our results identify SMYD3 as a new coactivator for ER-mediated transcription, providing a possible link between SMYD3 overexpression and breast cancer.
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Clock gene mouse period2 overexpression inhibits growth of human pancreatic cancer cells and has synergistic effect with cisplatin.
Anticancer Res.
PUBLISHED: 05-06-2009
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Circadian rhythms are the daily oscillations of multiple biological processes regulated by an endogenous clock. The Period2 gene is essential in controlling the circadian rhythm and plays an important role in tumor suppression. We examined whether the overexpression of the mouse Period2 gene (mPer2) in cultured tumor cells from human tissues inhibits cell growth, using the recombinant adenovirus vector AdmPer2. The overexpression of mPer2 in human pancreatic cancer cells (Panc1, Aspc1) reduced cellular proliferation and induced apoptotic cell death. Infection with AdmPer2 also inhibited cell-cycle progression, inducing arrest at the G(2)-M phase. Western blotting analyses confirmed that infection with AdmPer2 reduced Bcl-X(L), Cdc2 and cyclin B1 protein, whereas it increased Bax protein in Aspc1 cells. The overexpression of mPer2 suppressed Cdc2 kinase activity. Moreover, infection with AdmPer2 resulted in dose-dependent synergic cell killing effects with the anticancer agent cisplatin (CDDP) in human pancreatic cancer cells. This synergic effect might be related to the reduction of Bcl-X(L) induced by infection with AdmPer2. Our results suggest that the circadian gene Period2 may play an important role in suppression of cell proliferation in human cancer, and additionally Period2 gene expression level may influence the sensitivity to cisplatin depending on Bcl-X(L) expression level.
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Dexamethasone-conjugated polyethylenimine as an efficient gene carrier with an anti-apoptotic effect to cardiomyocytes.
J Gene Med
PUBLISHED: 03-21-2009
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Dexamethasone is a potent glucocorticoid with anti-inflammatory effects. Dexamethasone can protect ischemic cardiomyocytes from apoptosis. To apply the anti-apoptotic effect of dexamethasone to ischemic disease gene therapy, dexamethasone-conjugated polyethylenimine (PEI-Dexa) was synthesized and evaluated as an anti-apoptotic gene carrier.
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Myeloid differentiation factor 88 regulates basal and UV-induced expressions of IL-6 and MMP-1 in human epidermal keratinocytes.
J. Invest. Dermatol.
PUBLISHED: 02-28-2009
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Myeloid differentiation factor 88 (MyD88) is known as an adaptor protein for the Toll-like receptor (TLR) family and participates in signal transduction by binding to the cytoplasmic Toll/IL-1 receptor (TIR) domains of activated TLR. In this study, we demonstrated that expression of MyD88 is increased in photoaged skin compared with intrinsic aged human skin of the same elderly individuals, and that acute UV irradiation increases MyD88 expression in human skin in vivo. To investigate the effects of these high levels of MyD88 in photoaged skin and acutely UV-irradiated skin, human epidermal keratinocytes were infected with adenovirus expressing wild-type (MyD88wt), dominant-positive (MyD88DeltaC), and dominant-negative (MyD88DeltaN) MyD88 forms. Overexpression of MyD88wt and MyD88DeltaC, but not of MyD88DeltaN, increased the basal expressions of IL-6 and matrix metalloproteinase-1 (MMP-1) in human epidermal keratinocytes. Moreover, overexpression of MyD88DeltaN prevented UV-induced expressions of IL-6 and MMP-1 by inhibiting UV-induced activation of NF-kappaB and activating protein-1. These results suggest that MyD88 is important in IL-6 and MMP-1 expressions in both acutely UV-irradiated skin and in chronically sun-exposed human skin.
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Escherichia coli transport in porous media: influence of cell strain, solution chemistry, and temperature.
Colloids Surf B Biointerfaces
PUBLISHED: 02-03-2009
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Packed bed column and complementary characterization experiments were carried out with two Escherichia coli strains (D21 g and XL1-Blue) under a range of ionic strength (IS) and valence (KCl, CaCl(2), and artificial groundwater) to determine the role of bacterial strain and solution chemistry on cell adhesion. Increasing IS and valence had a marked effect on the electrokinetic and surface properties of bacteria and quartz grains; hence resulting in a greater rate of deposition. Distinct deposition trends were observed for the two cell strains, with greater retention observed for D21 g versus XL1-Blue across the range of IS. Selected transport and characterization experiments were also conducted with the D21 g cells, finding deposition also increasing with IS and valence. In the presence of Ca(2+) bacterial deposition behavior deviated from anticipated trends and it is concluded from additional analysis that Ca(2+) ions influence bacterial surface charge, hydrophobicity, and extracellular polymers. Further transport experiments were conducted with the D21 g cells and colloids to establish the role of temperature (4, 10 and 25 degrees C). Results suggested that a combination of specific and non-specific interactions occurring between the cells and quartz determines the extent of deposition, rather than transport from the bulk to the collector surface.
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Macromolecule mediated transport and retention of Escherichia coli O157:H7 in saturated porous media.
Water Res.
PUBLISHED: 01-28-2009
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The role of extracellular macromolecules on Escherichia coli O157:H7 transport and retention was investigated in saturated porous media. To compare the relative transport and retention of E. coli cells that are macromolecule rich and deficient, macromolecules were partially cleaved using a proteolytic enzyme. Characterization of bacterial cell surfaces, cell aggregation, and experiments in a packed sand column were conducted over a range of ionic strength (IS). The results showed that macromolecule-related interactions contribute to retention of E. coli O157:H7 and are strongly linked to solution IS. Under low IS conditions (IS < or = 0.1 mM), partial removal of the macromolecules resulted in a more negative electrophoretic mobility of cells and created more unfavorable conditions for cell-quartz and cell-cell interactions as suggested by Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energy profiles and cell aggregation kinetics. Consequently, less retention was observed for enzyme treated cells in the corresponding column experiments. In addition, a time-dependent deposition process (i.e., ripening) was observed for untreated cells, but not for treated cells, supporting the fact that the macromolecules enhanced cell-cell interactions. Additional column experiments for untreated cells under favorable conditions (IS > or = 1 mM) showed that a significant amount of the cells were reversibly retained in the column, which contradicts predictions of DLVO theory. Furthermore, a non-monotonic cell retention profile was observed under favorable attachment conditions. These observations indicated that the presence of macromolecules hindered irreversible interactions between the cells and the quartz surface.
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Prevalence of p16 methylation and prognostic factors in plasma cell myeloma at a single institution in Korea.
Ann Lab Med
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The primary purpose of this study was to investigate the prevalence and characteristics of p16 methylation and determine the prognostic implications of the clinical data, hematologic data, and p16 methylation changes in plasma cell myeloma (PCM).
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Bactericidal activity of Ag-doped multi-walled carbon nanotubes and the effects of extracellular polymeric substances and natural organic matter.
Colloids Surf B Biointerfaces
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The objective of this study was to determine the bactericidal mechanisms of Ag-doped multi-walled carbon nanotube (MWCNT) nanoparticles (Ag(0)/MWCNTs) to Escherichia coli DH5?. The contributions of silver ion dissolution, reactive species, and direct contact on bacteria inactivation were systematically determined. The relatively higher survival rate of bacteria exposed to 0.02mgL(-1) Ag(+) ions (the maximum concentration of Ag(+) ions dissolved from Ag(0)/MWCNTs) suggested that the antibacterial property of Ag(0)/MWCNTs was not caused by silver ion dissolution. The effects of each reactive species ((·)OH, H(2)O(2), (·)O(2)(-), h(+), and e(-)) on the disinfection process were investigated by using multiple scavengers, and the results showed that (·)OH(b), (·)OH(s), and h(+) play important roles in bactericidal actions. The significance of (·)OH(b), (·)OH(s), and h(+) in the disinfection process was further confirmed in the partition systems combined with scavenger. The antibacterial effects of these reactive species mainly arose through direct contact of the nanocomposites with the bacteria. The effects of extracellular polymeric substances (EPS) and natural organic matter (NOM) on the inactivation of bacteria were also investigated. The lower antibacterial effect observed for EPS-rich bacteria relative to EPS-poor bacteria demonstrated the protective effects of EPS in the disinfection system. The decreased bacterial toxicity effect acquired by the addition of humic acid (as the model NOM) in the disinfection system demonstrated the influence of NOM on the bacterial toxicity of nanocomposites, where the sorption of NOM onto the surface of the nanocomposites contributed to the decreased antibacterial effects.
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Association between Household Income and Asthma Symptoms among Elementary School Children in Seoul.
Environ Health Toxicol
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This study examined the association between socioeconomic factors and asthma symptoms.
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Initial transport and retention behaviors of ZnO nanoparticles in quartz sand porous media coated with Escherichia coli biofilm.
Environ. Pollut.
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The significance of biofilm on the transport and deposition behaviors of ZnO nanoparticles were examined under a series of environmentally relevant ionic strength at two fluid velocities of 4 m-d(-1) and 8 m-d(-1). Biofilm enhanced nanoparticles retention in porous media under all examined conditions. The greater deposition was also observed in extracellular polymeric substances (EPS) coated surfaces by employment of quartz microbalance with dissipation (QCM-D) system. Derjaguin-Landau-Verwey-Overbeek (DLVO) failed to interpret more ZnO nanoparticles deposition on biofilm (EPS) coated silica surfaces. Chemical interaction and physical morphology of biofilm contributed to this greater deposition (retention). Biofilm affected the spacial distribution of retained ZnO nanoparticles as well. Relatively steeper slope of retained profiles were observed in the presence of biofilm, corresponding to the greater deviation from colloid filtration theory (CFT). Pore space constriction via biofilm induced more nanoparticle trapped in the column inlet, leading to greater deviations (?ln k(f)) from the CFT.
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Influence of nutrient conditions on the transport of bacteria in saturated porous media.
Colloids Surf B Biointerfaces
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The influence of nutrient conditions on the transport of bacteria in packed porous media was examined in both NaCl and CaCl(2)-NaCl mixed solutions at pH 6.0. Two representative cell types, Bacillus subtilis (Gram-positive) and Escherichia coli DH5? (Gram-negative), were used to determine the influence of nutrient conditions on cell transport behavior. Under all examined solution conditions, the breakthrough plateaus in the presence of background nutrients in solutions for both examined bacteria types were higher than those without nutrients, indicating that the presence of nutrients in solution enhanced the bacteria transport regardless of the examined cell type (Gram-positive or Gram-negative) and solution chemistry (ionic strength and ion valence). The increased bacteria transport induced by the presence of nutrient in solutions was probably not driven by the changes in the sizes of bacteria, cell surface properties (i.e., zeta potentials), or the contents of extracellular polymeric substances (EPS) since these properties were not obviously changed by the presence of nutrients in solutions. Nutrient pre-equilibration experiments demonstrated that the deposition site competition by nutrients contributed to the increased bacteria transport observed with the presence of nutrients in bacterial suspension. Additional nutrient effects on cell transport were examined from the column experiments conducted in the absence of nutrients for the cells under 2-day starvation. Starvation of bacteria also increased the bacteria transport in porous media. The sizes of bacteria, zeta potentials of bacteria, and the EPS composition were changed by the starvation process, which might be responsible for the increased transport of starved bacteria observed for both cell types examined under all solution conditions.
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Interferon gamma mRNA quantitative real-time polymerase chain reaction for the diagnosis of latent tuberculosis: a novel interferon gamma release assay.
Diagn. Microbiol. Infect. Dis.
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The interferon gamma (IFN-?) release assay (IGRA) is widely used as a diagnostic method for latent tuberculosis infection (LTBI). The QuantiFERON-TB Gold and QuantiFERON-TB Gold In-tube (QFT-IT) tests measure plasma IFN-? levels using enzyme-linked immunosorbent assay (ELISA), and T-SPOT.TB counts IFN-?-producing cells using enzyme-linked immunosorbent spot assay. IFN-? mRNA was evaluated as an indicator of IGRA in comparison with QFT-IT IFN-? ELISA in 46 subjects with active TB and in 73 at low risk for TB. Significant IFN-? mRNA expression was detected from 30 min and peaked 4 h after stimulation with MTB antigens or mitogen. This was defined as the optimal time point for IFN-? mRNA real-time polymerase chain reaction (PCR). The sensitivities of IFN-? mRNA real-time PCR and IFN-? ELISA were 84.8% (39/46) and 89.1% (41/46), respectively (no significant difference). Although the specificities of IFN-? ELISA was 4.1% higher than that of IFN-? mRNA real-time PCR (60.3% versus 56.2%), the difference was not statistically significant. The overall agreement between IFN-? mRNA real-time PCR and IFN-? ELISA was 79.8% (kappa = 0.475). Whilst there was no difference in the performance of IFN-? mRNA real-time PCR and IFN-? ELISA, IFN-? mRNA real-time PCR was superior to IFN-? ELISA in terms of the time required for detection of MTB infection.
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Why patients in critical care do not receive adequate enteral nutrition? A review of the literature.
J Crit Care
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Enteral nutrition is frequently used to provide nutrients for critically ill patients. However, only about half of critically ill enterally fed patients receive their energy requirements. Underfeeding is associated with detrimental clinical outcomes including infection, pressure ulcers, impaired wound healing, prolonged hospital stays, and increased morbidity and mortality. This literature review was conducted to identify major barriers to adequate enteral nutrition intake in critically ill adults and to identify gaps in the research literature. Studies (n = 30) reviewed addressed adult patients in critical care, published since 1999, and written in English. Findings showed that factors that explain inadequate enteral nutritional intake include delayed initiation of enteral nutrition and slow advancement of infusion rate, underprescription, incomplete delivery of prescribed nutrition, and frequent interruption of enteral nutrition. Frequent interruption was caused by diagnostic tests, surgical procedures, gastrointestinal intolerance, feeding tube problems, and routine nursing procedures. There are no standardized protocols that address these barriers to receiving adequate enteral intake. Such protocols must be developed, implemented, and tested to address undernutrition and mitigate the negative consequences of inadequate enteral intake.
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