Science.gov

Sample records for dpd utilizando estrategias

  1. Efficient Algorithms for Langevin and DPD Dynamics.

    PubMed

    Goga, N; Rzepiela, A J; de Vries, A H; Marrink, S J; Berendsen, H J C

    2012-10-09

    In this article, we present several algorithms for stochastic dynamics, including Langevin dynamics and different variants of Dissipative Particle Dynamics (DPD), applicable to systems with or without constraints. The algorithms are based on the impulsive application of friction and noise, thus avoiding the computational complexity of algorithms that apply continuous friction and noise. Simulation results on thermostat strength and diffusion properties for ideal gas, coarse-grained (MARTINI) water, and constrained atomic (SPC/E) water systems are discussed. We show that the measured thermal relaxation rates agree well with theoretical predictions. The influence of various parameters on the diffusion coefficient is discussed.

  2. [Dihydropirymidine dehydrogenase (DPD)--a toxicity marker for 5-fluorouracil?].

    PubMed

    Jedrzychowska, Adriana; Dołegowska, Barbara

    2013-01-01

    In proceedings relating to patients suffering from cancer, an important step is predicting response and toxicity to treatment. Depending on the type of cancer, physicians use the generally accepted schema of treatment, for example pharmacotherapy. 5-fluorouracil (5-FU) is the most widely used anticancer drug in chemotherapy for colon, breast, and head and neck cancer. Patients with dihydropyrimidine dehydrogenase (DPD) deficiency, which is responsible for the metabolism of 5-FU, may experience severe side effects during treatment, and even death. In many publications the need for determining the activity of DPD is discussed, which would protect the patient from the numerous side effects of treatment. However, in practice these assays are not done routinely, despite the high demand. In most cases, a genetic test is used to detect changes in the gene encoding DPD (such as in the USA), but because of the large number of mutations the genetic test cannot be used as a screening test. Dihydropyrimidine dehydrogenase activity has been shown to have high variability among the general population, with an estimated proportion of at least 3-5% of individuals showing low or deficient DPD activity. In this publication we presents data about average dihydropirymidine dehydrogenase activity in various populations of the world (e.g. Japan, Ghana, Great Britain) including gender differences and collected information about the possibility of determination of DPD activity in different countries. Detection of reduced DPD activity in patients with planned chemotherapy will allow a lower dosage of 5-FU or alternative treatment without exposing them to adverse reactions.

  3. Single-particle hydrodynamics in DPD: A new formulation

    NASA Astrophysics Data System (ADS)

    Pan, W.; Pivkin, I. V.; Karniadakis, G. E.

    2008-10-01

    We present a new formulation of dissipative particle dynamics (DPD) that leads to correct hydrodynamics in flows around bluff bodies represented by a single particle. In particular, we introduce a shear drag coefficient and a corresponding term in the dissipative force, which along with the angular momentum incorporate non-central shear forces between particles and preserve angular momentum. We consider several prototype flows to verify the performance of the proposed formulation with comparisons against theoretical and continuum-based simulation results. Our method is similar to the Fluid Particle Method (FPM) of Espanol (Phys. Rev. E, 57 (1998) 2930) and it has the computational and implementation simplicity of the standard DPD approach.

  4. Entanglement effect in polymer melts by Dissipative Particle Dynamics (DPD)

    NASA Astrophysics Data System (ADS)

    Khani, Shaghayegh; Maia, Joao

    2015-03-01

    Dissipative Particle Dynamics (DPD) is a mesoscale simulation method that has shown a very good potential in modeling different soft matter systems from colloidal suspensions to highly entangled polymers. Like any other simulation technique DPD is associated with some deficiencies, for instance in the case of entangled polymers soft repulsions used in DPD allow particle overlap which may result in topology violations that prevent the correct capturing of the entanglement effect. Therefore, in the present work in order to properly reproduce the dynamics and viscoelastic properties of polymers the soft repulsions between the particles are substituted with a repulsive potential between non-adjacent bonds of different FENE chains. Also, DPD is a coarse-grained simulation method that can be used to model time and length scales longer than atomistic models; however, due to the existence of an upper level limit for the level of coarse graining this method is not applicable for the whole mesoscopic range. Thus, this work represents a new approach for tuning the level of coarse-graining by adjusting the simulation parameters. The ability of the method in capturing the entanglement effects is validated by simulating dynamic and viscoelastic properties of polymers.

  5. Reducing the effects of compressibility in DPD-based blood flow simulations through severe stenotic microchannels

    NASA Astrophysics Data System (ADS)

    Gao, Chao; Zhang, Peng; Marom, Gil; Deng, Yuefan; Bluestein, Danny

    2017-04-01

    Viscous fluid flow simulations based on dissipative particle dynamics (DPD) may bear compressible flow effects when flowing through severe stenotic geometries. This is caused by the soft repulsive potential employed in the DPD force field, which limits the particle-based fluid system ability to sustain a large degree of compression. To mitigate this problem, a Morse potential was added to the DPD force field. We studied the fluid properties of the modified fluid model (DPD-Morse) and compared it with a previously published conventional DPD based fluid model. Our DPD-Morse model demonstrated reduced compressibility while preserving other fluid properties such as the fluid density and viscosity. We further investigated the fluid flow properties for a severe 3D stenotic microchannel with a 67% stenosis, using the two models. The DPD fluid model presented a significant density gradient along the flow direction, where the fluid density increased upstream towards the stenosis and decreased downstream from the stenosis before regaining its initial value. In contrast, the DPD-Morse model demonstrated a far better uniform fluid density distribution along the flow direction. We compared both solutions with CFD simulations. The DPD-Morse fluid resembled the behavior of the continuum fluid model whereas DPD fluid deviated from it. To estimate the effect that the difference between the two DPD formulations may have on the platelet activation potential, we have further embedded a platelet model within the flow field and investigated the shear stress accumulation along the platelet transport trajectory. In the stenotic section, the DPD fluid demonstrated a larger stress gradient than the DPD-Morse fluid. The platelet transport period was shorter for the DPD fluid as it generated a larger fluid density gradient that overestimated the acceleration of the platelet through the stenosis. With reduced fluid compressibility, our modified DPD-Morse fluid model was more accurate than the

  6. Comparison of Facts and DPD-Steadifac Procedures for Free and Combined Chlorine in Aqueous Solution.

    DTIC Science & Technology

    1980-01-01

    of Nitrogen Trichloride. 13 2. Interference of Monochloramine on the DPD Procedure in Synthetic Waters ........... ... ..... ... .. 17 3. Comparison... Monochloramine with the FACTS Procedure Using Synthetic Waters ..... ..... ......................... 14 2. Interference of Monochloramine with the DPD...Procedure in Synthetic W.aters .......... ......................... 16 3. Interference of Monochloramine with the DPD-STEADIFAC Modified Procedure in

  7. Qualitative Estimation of Drug Entrapment Efficiency in Polymeric Nano - Micelles Using Dissipative Particle Dynamics (DPD).

    PubMed

    Hadizadeh, Farzin; Shamsara, Jamal

    2017-01-01

    Dissipative particle dynamics (DPD) is a simulation method that has one of its applications in the field of pharmaceutical science and drug delivery. DPD is employed to study morphology and some other characteristics of polymeric nanomicelles. Two systems were considered in this study: system A which includes curcumin, Polycaprolactone (PCL), Polyethylene glycol (PEG) and water beads and system B which includes paclitaxel, Polylactic acid (PLA), PEG and water beads. In this study we focused on the simulation of drug entrapment in polymeric micelles using DPD method. Results indicated that the qualitative comparison of polymeric-micelles with different compositions, after carefully tuning input parameters and simulation conditions, can be successfully performed using DPD. Considering real state of a system for DPD simulation will have a great impact on the reliability of the simulation results. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  8. Etiology of amyloidosis determines myocardial 99mTc-DPD uptake in amyloidotic cardiomyopathy.

    PubMed

    Longhi, Simone; Bonfiglioli, Rachele; Obici, Laura; Gagliardi, Christian; Milandri, Agnese; Lorenzini, Massimiliano; Guidalotti, Pier Luigi; Merlini, Giampaolo; Rapezzi, Claudio

    2015-05-01

    Tc-DPD (Tc-3,3-diphosphono-1,2-propanodicarboxylic acid) has a high affinity for transthyretin (TTR)-infiltrated myocardium, allowing a differential diagnosis with light chain cardiac amyloidosis and other nonamyloidotic cardiomyopathies with a hypertrophic phenotype, in which myocardial tracer uptake is low or absent. Myocardial bone tracer uptake in the rarer forms of amyloidosis (eg, apolipoprotein-related) has been rarely studied. We present 4 cases of cardiac amyloidosis that underwent Tc-DPD scintigraphy; myocardial DPD uptake was present in patients with ATTR, wtTTR and apolipoprotein AI and negative in cases with AL and apolipoprotein AII-related disease.

  9. 99mTc DPD is the preferential bone tracer for diagnosis of cardiac transthyretin amyloidosis.

    PubMed

    Rossi, Pascal; Tessonnier, Laurent; Frances, Yves; Mundler, Olivier; Granel, Brigitte

    2012-08-01

    We emphasize the role of Tc-99m-3,3-diphosphono-1,2-propanodicarboxylicacid (DPD) scintigraphy as a noninvasive tool to distinguish transthyretin (TTR)-related cardiac amyloidosis from other forms of cardiac amyloidosis. We report the case of a 76-year-old male patient suffering from congestive heart failure in whom imaging investigation by DPD scintigraphy showed a strong cardiac uptake highly suggestive of TTR amyloidosis variant. TTR-related cardiac amyloidosis was confirmed on myocardial biopsies by immunohistochemistry analysis. This case supports the growing interest in DPD scintigraphy for typing cardiac amyloidosis and for its contribution in the place of invasive myocardial biopsy.

  10. Dihydropyrimidine dehydrogenase (DPD) expression is negatively regulated by certain microRNAs in human lung tissues.

    PubMed

    Hirota, Takeshi; Date, Yuko; Nishibatake, Yu; Takane, Hiroshi; Fukuoka, Yasushi; Taniguchi, Yuuji; Burioka, Naoto; Shimizu, Eiji; Nakamura, Hiroshige; Otsubo, Kenji; Ieiri, Ichiro

    2012-07-01

    Dihydropyrimidine dehydrogenase (DPD) is important to the antitumor effect of 5-fluorouracil (5-FU). DPD gene (DPYD) expression in tumors is correlated with sensitivity to 5-FU. Because the 5-FU accumulated in cancer cells is also rapidly converted into inactivated metabolites through catabolic pathways mediated by DPD, high DPD activity in cancer cells is an important determinant of the response to 5-FU. DPD activity is highly variable and reduced activity causes a high risk of 5-FU toxicity. Genetic variation in DPYD has been proposed as the main factor responsible for the variation in DPD activity. However, only a small proportion of the activity of DPD can be explained by DPYD mutations. In this study, we found that DPYD is a target of the following microRNAs (miRNA): miR-27a, miR-27b, miR-134, and miR-582-5p. In luciferase assays with HepG2 cells, the overexpression of these miRNAs was associated with significantly decreased reporter activity in a plasmid containing the 3'-UTR of DYPD mRNA. The level of DPD protein in MIAPaca-2 cells was also significantly decreased by the overexpression of these four miRNAs. The results suggest that miR-27a, miR-27b, miR-134, and miR-582-5p post-transcriptionally regulate DPD protein expression. The levels of miRNAs in normal lung tissue and lung tumors were compared; miR-27b and miR-134 levels were significantly lower in the tumors than normal tissue (3.64 ± 4.02 versus 9.75 ± 6.58 and 0.64 ± 0.75 versus 1.48 ± 1.39). DPD protein levels were significantly higher in the tumors. Thus, the decreased expression of miR-27b would be responsible for the high levels of DPD protein. This study is the first to show that miRNAs regulate the DPD protein, and provides new insight into 5-FU-based chemotherapy.

  11. Investigation of particles size effects in Dissipative Particle Dynamics (DPD) modelling of colloidal suspensions

    NASA Astrophysics Data System (ADS)

    Mai-Duy, N.; Phan-Thien, N.; Khoo, B. C.

    2015-04-01

    In the Dissipative Particle Dynamics (DPD) simulation of suspension, the fluid (solvent) and colloidal particles are replaced by a set of DPD particles and therefore their relative sizes (as measured by their exclusion zones) can affect the maximal packing fraction of the colloidal particles. In this study, we investigate roles of the conservative, dissipative and random forces in this relative size ratio (colloidal/solvent). We propose a mechanism of adjusting the DPD parameters to properly model the solvent phase (the solvent here is supposed to have the same isothermal compressibility to that of water).

  12. Morphological transformations in polymer brushes in binary mixtures: DPD study.

    PubMed

    Cheng, Jianli; Vishnyakov, Aleksey; Neimark, Alexander V

    2014-11-04

    Morphological transformations in polymer brushes in a binary mixture of good and bad solvents are studied using dissipative particle dynamics simulations drawing on a characteristic example of polyisoprene natural rubber in an acetone-benzene mixture. A coarse-grained DPD model of this system is built based on the experimental data in the literature. We focus on the transformation of dense, collapsed brush in bad solvent (acetone) to expanded brush solvated in good solvent (benzene) as the concentration of benzene increases. Compared to a sharp globule-to-coil transition observed in individual tethered chains, the collapsed-to-expanded transformation in brushes is found to be gradual without a prominent transition point. The transformation becomes more leveled as the brush density increases. At low densities, the collapsed brush is highly inhomogeneous and patterned into bunches composed of neighboring chains due to favorable polymer-polymer interaction. At high densities, the brush is expanded even in bad solvent due to steric restrictions. In addition, we considered a model system similar to the PINR-acetone-benzene system, but with the interactions between the solvent components worsened to the limit of miscibility. Enhanced contrast between good and bad solvents facilitates absorption of the good solvent by the brush, shifting the collapsed-to-expanded transformation to lower concentrations of good solvent. This effect is especially pronounced for higher brush densities.

  13. cDPD: A new dissipative particle dynamics method for modeling electrokinetic phenomena at the mesoscale.

    PubMed

    Deng, Mingge; Li, Zhen; Borodin, Oleg; Karniadakis, George Em

    2016-10-14

    We develop a "charged" dissipative particle dynamics (cDPD) model for simulating mesoscopic electrokinetic phenomena governed by the stochastic Poisson-Nernst-Planck and the Navier-Stokes equations. Specifically, the transport equations of ionic species are incorporated into the DPD framework by introducing extra degrees of freedom and corresponding evolution equations associated with each DPD particle. Diffusion of ionic species driven by the ionic concentration gradient, electrostatic potential gradient, and thermal fluctuations is captured accurately via pairwise fluxes between DPD particles. The electrostatic potential is obtained by solving the Poisson equation on the moving DPD particles iteratively at each time step. For charged surfaces in bounded systems, an effective boundary treatment methodology is developed for imposing both the correct hydrodynamic and electrokinetics boundary conditions in cDPD simulations. To validate the proposed cDPD model and the corresponding boundary conditions, we first study the electrostatic structure in the vicinity of a charged solid surface, i.e., we perform cDPD simulations of the electrostatic double layer and show that our results are in good agreement with the well-known mean-field theoretical solutions. We also simulate the electrostatic structure and capacity densities between charged parallel plates in salt solutions with different salt concentrations. Moreover, we employ the proposed methodology to study the electro-osmotic and electro-osmotic/pressure-driven flows in a micro-channel. In the latter case, we simulate the dilute poly-electrolyte solution drifting by electro-osmotic flow in a micro-channel, hence demonstrating the flexibility and capability of this method in studying complex fluids with electrostatic interactions at the micro- and nano-scales.

  14. cDPD: A new dissipative particle dynamics method for modeling electrokinetic phenomena at the mesoscale

    NASA Astrophysics Data System (ADS)

    Deng, Mingge; Li, Zhen; Borodin, Oleg; Karniadakis, George Em

    2016-10-01

    We develop a "charged" dissipative particle dynamics (cDPD) model for simulating mesoscopic electrokinetic phenomena governed by the stochastic Poisson-Nernst-Planck and the Navier-Stokes equations. Specifically, the transport equations of ionic species are incorporated into the DPD framework by introducing extra degrees of freedom and corresponding evolution equations associated with each DPD particle. Diffusion of ionic species driven by the ionic concentration gradient, electrostatic potential gradient, and thermal fluctuations is captured accurately via pairwise fluxes between DPD particles. The electrostatic potential is obtained by solving the Poisson equation on the moving DPD particles iteratively at each time step. For charged surfaces in bounded systems, an effective boundary treatment methodology is developed for imposing both the correct hydrodynamic and electrokinetics boundary conditions in cDPD simulations. To validate the proposed cDPD model and the corresponding boundary conditions, we first study the electrostatic structure in the vicinity of a charged solid surface, i.e., we perform cDPD simulations of the electrostatic double layer and show that our results are in good agreement with the well-known mean-field theoretical solutions. We also simulate the electrostatic structure and capacity densities between charged parallel plates in salt solutions with different salt concentrations. Moreover, we employ the proposed methodology to study the electro-osmotic and electro-osmotic/pressure-driven flows in a micro-channel. In the latter case, we simulate the dilute poly-electrolyte solution drifting by electro-osmotic flow in a micro-channel, hence demonstrating the flexibility and capability of this method in studying complex fluids with electrostatic interactions at the micro- and nano-scales.

  15. User Manual and Source Code for a LAMMPS Implementation of Constant Energy Dissipative Particle Dynamics (DPD-E)

    DTIC Science & Technology

    2014-06-01

    Distribution List 20 iv INTENTIONALLY LEFT BLANK. 1 The constant energy dissipative particle dynamics ( DPD -E) method is implemented into the Large-Scale...User Manual and Source Code for a LAMMPS Implementation of Constant Energy Dissipative Particle Dynamics ( DPD -E) by James P. Larentzos...Energy Dissipative Particle Dynamics ( DPD -E) James P. Larentzos Engility Corporation John K. Brennan, Joshua D. Moore, and William D. Mattson

  16. Hydrogen bonding in DPD: application to low molecular weight alcohol-water mixtures.

    PubMed

    Kacar, Gokhan; de With, Gijsbertus

    2016-04-14

    In this work we propose a computational approach to mimic hydrogen bonding in a widely used coarse-grained simulation method known as dissipative particle dynamics (DPD). The conventional DPD potential is modified by adding a Morse potential term to represent hydrogen bonding attraction. Morse potential parameters are calculated by a mapping of energetic and structural properties to those of atomistic scale simulations. By the addition of hydrogen bonding to DPD and with the proposed parameterization, the volumetric mixing behavior of low molecular weight alcohols and water is studied and experimentally observed negative volume excess is successfully predicted, contrary to the conventional DPD implementation. Moreover, the density-dependent DPD parameterization employed provides the asymmetrical shapes of the excess volume curves. In addition, alcohol surface enrichment at the air interface and self-assembly in the bulk is studied. The surface concentrations of alcohols at the air interface compare favorably with the experimental observations at all bulk-phase alcohol fractions and, in consonance with experiment, some clustering is observed.

  17. Delayed Presentation of DPD Deficiency in Colorectal Cancer.

    PubMed

    Law, Lindsey; Rogers, Jane; Eng, Cathy

    2014-05-01

    L, his hemoglobin was 13.1 g/dL, his hematocrit was 39.2%, and his platelet count was 68,000/ìL. He was admitted to the inpatient service and started on empiric antibiotics. His blood cultures remained negative during hospitalization, but stool cultures were positive for C. difficile. His antimicrobial regimen was deescalated to oral vancomycin once his stool volume decreased. He was treated with an institutional compounded mouthwash of diphenhydramine, aluminum/magnesium hydroxide, and viscous lidocaine for the mucositis, which also slowly improved. He was given a dose of growth factor. Neutropenia eventually resolved, with an absolute neutrophil count of 4,820/ìL on the day of discharge. He was discharged 26 days after initiating cycle 1, at which time his myelosuppression and mucositis were also resolved. Throughout his course, he did not report any neurotoxicity. DPD Testing  Due to his severe symptoms of neutropenia, mucositis, and diarrhea, Mr. D. was tested for dihydropyrimidine dehydrogenase (DPD) deficiency. Testing confirmed a heterozygous IVS14+IG>A mutation. For this reason, all further adjuvant therapy was withheld, and he was followed on clinical surveillance only.

  18. Delayed Presentation of DPD Deficiency in Colorectal Cancer

    PubMed Central

    Law, Lindsey; Rogers, Jane; Eng, Cathy

    2014-01-01

    to 160/ìL, his hemoglobin was 13.1 g/dL, his hematocrit was 39.2%, and his platelet count was 68,000/ìL. He was admitted to the inpatient service and started on empiric antibiotics. His blood cultures remained negative during hospitalization, but stool cultures were positive for C. difficile. His antimicrobial regimen was deescalated to oral vancomycin once his stool volume decreased. He was treated with an institutional compounded mouthwash of diphenhydramine, aluminum/magnesium hydroxide, and viscous lidocaine for the mucositis, which also slowly improved. He was given a dose of growth factor. Neutropenia eventually resolved, with an absolute neutrophil count of 4,820/ìL on the day of discharge. He was discharged 26 days after initiating cycle 1, at which time his myelosuppression and mucositis were also resolved. Throughout his course, he did not report any neurotoxicity. DPD Testing  Due to his severe symptoms of neutropenia, mucositis, and diarrhea, Mr. D. was tested for dihydropyrimidine dehydrogenase (DPD) deficiency. Testing confirmed a heterozygous IVS14+IG>A mutation. For this reason, all further adjuvant therapy was withheld, and he was followed on clinical surveillance only. PMID:25089219

  19. Translating DPYD genotype into DPD phenotype: using the DPYD gene activity score.

    PubMed

    Henricks, Linda M; Lunenburg, Carin A T C; Meulendijks, Didier; Gelderblom, Hans; Cats, Annemieke; Swen, Jesse J; Schellens, Jan H M; Guchelaar, Henk-Jan

    2015-01-01

    The dihydropyrimidine dehydrogenase enzyme (DPD, encoded by the gene DPYD) plays a key role in the metabolism of fluoropyrimidines. DPD deficiency occurs in 4-5% of the population and is associated with severe fluoropyrimidine-related toxicity. Several SNPs in DPYD have been described that lead to absent or reduced enzyme activity, including DPYD*2A, DPYD*13, c.2846A>T and c.1236G>A/haplotype B3. Since these SNPs differ in their effect on DPD enzyme activity, a differentiated dose adaption is recommended. We propose the gene activity score for translating DPYD genotype into phenotype, accounting for differences in functionality of SNPs. This method can be used to standardize individualized fluoropyrimidine dose adjustments, resulting in optimal safety and effectiveness.

  20. Application of DPD in the design of polymeric nano-micelles as drug carriers.

    PubMed

    Ramezani, Mohammad; Shamsara, Jamal

    2016-05-01

    Developing new drug carrier systems are of a great importance in the treatment approach for a wide range of diseases. The simulation techniques can be valuable for decreasing the time and cost of developing novel drug carriers. Among the simulation methods there are a vast number of studies using dissipative particle dynamics (DPD) method for the prediction of different aspects of polymeric nano-micelles for encapsulating drugs. Here, we reviewed the results of the studies employing DPD for the simulation of drug loading and release in different polymeric micelles carriers. In some cases the simulation results were compared with the experimental results by the authors that were demonstrated the reliability of the DPD predictions.

  1. DPD epitope-specific glutamic acid decarboxylase GAD)65 autoantibodies in children with Type 1 diabetes

    USDA-ARS?s Scientific Manuscript database

    To study whether DPD epitope-specific glutamate decarboxylase autoantibodies are found more frequently in children with milder forms of Type 1 diabetes. We prospectively evaluated 75 children with new-onset autoimmune Type 1 diabetes, in whom we collected demographic, anthropometric and clinical dat...

  2. (99m)Tc-DPD uptake reflects amyloid fibril composition in hereditary transthyretin amyloidosis.

    PubMed

    Pilebro, Björn; Suhr, Ole B; Näslund, Ulf; Westermark, Per; Lindqvist, Per; Sundström, Torbjörn

    2016-01-01

    Aims In transthyretin amyloid (ATTR) amyloidosis various principal phenotypes have been described: cardiac, neuropathic, or a mixed cardiac and neuropathic. In addition, two different types of amyloid fibrils have been identified (type A and type B). Type B fibrils have thus far only been found in predominantly early-onset V30M and in patients carrying the Y114C mutation, whereas type A is noted in all other mutations currently examined as well as in wild-type ATTR amyloidosis. The fibril type is a determinant of the ATTR V30M disease phenotype. (99m)Tc-DPD scintigraphy is a highly sensitive method for diagnosing heart involvement in ATTR amyloidosis. The objective of this study was to determine the relationship between ATTR fibril composition and (99m)Tc-DPD scintigraphy outcome in patients with biopsy-proven ATTR amyloidosis. Methods Altogether 55 patients with biopsy-proven diagnosis of ATTR amyloidosis and amyloid fibril composition determined were examined by (99m)Tc-DPD scintigraphy. The patients were grouped and compared according to their type of amyloid fibrils. Cardiovascular evaluation included ECG, echocardiography, and cardiac biomarkers. The medical records were scrutinized to identify subjects with hypertension or other diseases that have an impact on cardiac dimensions. Results A total of 97% with type A and none of the patients with type B fibrils displayed (99m)Tc-DPD uptake at scintigraphy (p < 0.001). Findings from analyses of cardiac biomarkers, ECG, and echocardiography, though significantly different, could not differentiate between type A and B fibrils in individual patients. Conclusion In ATTR amyloidosis, the outcome of (99m)Tc-DPD scintigraphy is strongly related to the patients' transthyretin amyloid fibril composition.

  3. Development of DPD coarse-grained models: From bulk to interfacial properties.

    PubMed

    Solano Canchaya, José G; Dequidt, Alain; Goujon, Florent; Malfreyt, Patrice

    2016-08-07

    A new Bayesian method was recently introduced for developing coarse-grain (CG) force fields for molecular dynamics. The CG models designed for dissipative particle dynamics (DPD) are optimized based on trajectory matching. Here we extend this method to improve transferability across thermodynamic conditions. We demonstrate the capability of the method by developing a CG model of n-pentane from constant-NPT atomistic simulations of bulk liquid phases and we apply the CG-DPD model to the calculation of the surface tension of the liquid-vapor interface over a large range of temperatures. The coexisting densities, vapor pressures, and surface tensions calculated with different CG and atomistic models are compared to experiments. Depending on the database used for the development of the potentials, it is possible to build a CG model which performs very well in the reproduction of the surface tension on the orthobaric curve.

  4. Electronic structure and mesoscopic simulations of nonylphenol ethoxylate surfactants. a combined DFT and DPD study.

    PubMed

    Valencia, Diego; Aburto, Jorge; García-Cruz, Isidoro

    2013-08-07

    The aim of this work was to gain insight into the effect of ethylene oxide (EO) chains on the properties of a series of nonylphenol ethoxylate (NPE) surfactants. We performed a theoretical study of NPE surfactants by means of density functional theory (DFT) and dissipative particle dynamics (DPD). Both approximations were used separately to obtain different properties. Four NPEs were selected for this purpose (EO = 4, 7, 11 and 15 length chains). DFT methods provided some electronic properties that are related to the EO units. One of them is the solvation Gibbs energy, which exhibited a linear trend with EO chain length. DPD calculations allow us to observe the dynamic behavior in water of the NPE surfactants. We propose a coarse-grained model which properly simulates the mesophases of each surfactant. This model can be used in other NPEs applications.

  5. Development of DPD coarse-grained models: From bulk to interfacial properties

    NASA Astrophysics Data System (ADS)

    Solano Canchaya, José G.; Dequidt, Alain; Goujon, Florent; Malfreyt, Patrice

    2016-08-01

    A new Bayesian method was recently introduced for developing coarse-grain (CG) force fields for molecular dynamics. The CG models designed for dissipative particle dynamics (DPD) are optimized based on trajectory matching. Here we extend this method to improve transferability across thermodynamic conditions. We demonstrate the capability of the method by developing a CG model of n-pentane from constant-NPT atomistic simulations of bulk liquid phases and we apply the CG-DPD model to the calculation of the surface tension of the liquid-vapor interface over a large range of temperatures. The coexisting densities, vapor pressures, and surface tensions calculated with different CG and atomistic models are compared to experiments. Depending on the database used for the development of the potentials, it is possible to build a CG model which performs very well in the reproduction of the surface tension on the orthobaric curve.

  6. New modified weight function for the dissipative force in the DPD method to increase the Schmidt number

    NASA Astrophysics Data System (ADS)

    Yaghoubi, S.; Shirani, E.; Pishevar, A. R.; Afshar, Y.

    2015-04-01

    To simulate liquid fluid flows with high Schmidt numbers (Sc), one needs to use a modified version of the Dissipative Particle Dynamics (DPD) method. Recently the modifications made by others for the weight function of dissipative forces, enables DPD simulations for Sc, up to 10. In this paper, we introduce a different dissipative force weight function for DPD simulations that allows achieving a solution with higher values of Sc and improving the dynamic characteristics of the simulating fluid. Moreover, by reducing the energy of DPD particles, even higher values of Sc can be achieved. Finally, using the new proposed weight function and kBT =0.2 , the Sc values can reach up to 200.

  7. DPD Simulation of Protein Conformations: From α-Helices to β-Structures.

    PubMed

    Vishnyakov, Aleksey; Talaga, David S; Neimark, Alexander V

    2012-11-01

    We suggest a coarse-grained model for DPD simulations of polypeptides in solutions. The model mimics hydrogen bonding that stabilizes α-helical and β-structures using dissociable Morse bonds between quasiparticles representing the peptide groups amenable to hydrogen bonding. We demonstrate the capabilities of the model by simulating transitions between coil-like, globular, α-helical, and β-hairpin configurations of model peptides, varying Morse potential parameters, the hydrophobicities of residue side chains, and pH, which determines the charges of residue side chains. We construct a model triblock polypeptide mimicking the sequence of residues α-synuclein at two different pHs. The conformations of this model polypeptide depend on pH similarly to the behavior observed experimentally. The suggested approach to accounting for hydrogen bond formation within the general DPD framework may make the DPD method a competitive alternative to CGMD for modeling equilibrium and dynamic properties of proteins and polypeptides, especially during their transport in confined environments.

  8. Adsorption of SDS surfactant inside and around carbon nanotubes with DPD simulation

    NASA Astrophysics Data System (ADS)

    Vo, Minh; Papavassiliou, Dimitrios

    The inner diameter of a carbon nanotube (CNT) is generally from 1 to 20 nm, while its inner space could be filled by certain compounds. In our study, Dissipative Particle Dynamics (DPD) simulations were utilized to investigate the ability of sodium dodecyl sulfate (SDS) to adsorb inside a single-walled CNT. First of all, the DPD interaction parameters for SDS surfactants were validated by determining the CMC of surfactants from DPD calculation. The SDS micelle shape and size in water were also calculated. Water-CNT interactions were obtained from a prior study. When the SDS aqueous system reached equilibrium, an open-ended, hydrophobic CNT (a hollow cylinder in the simulation) was inserted into the solution. The diameter of the CNT varied from 1 to 5 nm. All simulations were run up to 2x106 time steps at room temperature. For the system of water and CNT, the radial and axial density profiles of water were computed and compared with published Molecular Dynamics results. In the presence of SDS, the distribution of water and SDS inside the CNT was found to be comparable to that in bulk solution after the system reached equilibrium. In addition, the diffusivity and residence time of water and SDS inside CNTs of different were calculated. This study would give insights into the dynamics and morphology of surfactants in nanoconfined structures.

  9. [Prevention of severe toxicity from capecitabine, 5-fluorouracil and tegafur by screening for DPD-deficiency].

    PubMed

    Deenen, Maarten J; Cats, Annemieke; Mandigers, Caroline M P W; Soesan, Marcel; Terpstra, Wim E; Beijnen, Jos H; Schellens, Jan H M

    2012-01-01

    Capecitabine, 5-fluorouracil and tegafur form the group called the fluoropyrimidines, which is one of the most frequently prescribed group of anti-cancer drugs for the treatment of (metastatic) colorectal, gastric and breast cancer. The primary enzyme responsible for the inactivation of the fluoropyrimidines is dihydropyrimidine dehydrogenase (DPD). Consequently, patients with an inborn partial DPD deficiency, induced, for example by the polymorphism DPYD*2A, are highly prone to severe, potentially lethal toxicity following a standard dose of fluoropyrimidines. In this article, based on three representative case reports and our prospective study in patients with cancer, we demonstrate the clinical value of prospective screening for DPD deficiency in patients being treated with fluoropyrimidine-based anti-cancer therapy. The results show that upfront genotyping for DPYD*2A followed by a fluoropyrimidine dose reduction of 50% (on average) in patients heterozygous polymorphic for DPYD*2A, significantly reduces the incidence of severe to potentially lethal toxicity compared to historical control patients given full-dose therapy.

  10. Severe fluoropyrimidine toxicity due to novel and rare DPYD missense mutations, deletion and genomic amplification affecting DPD activity and mRNA splicing.

    PubMed

    van Kuilenburg, André B P; Meijer, Judith; Maurer, Dirk; Dobritzsch, Doreen; Meinsma, Rutger; Los, Maartje; Knegt, Lia C; Zoetekouw, Lida; Jansen, Rob L H; Dezentjé, Vincent; van Huis-Tanja, Lieke H; van Kampen, Roel J W; Hertz, Jens Michael; Hennekam, Raoul C M

    2017-03-01

    Dihydropyrimidine dehydrogenase (DPD) is the initial and rate-limiting enzyme in the catabolism of 5-fluorouracil (5FU). Genetic variations in DPD have emerged as predictive risk factors for severe fluoropyrimidine toxicity. Here, we report novel and rare genetic variants underlying DPD deficiency in 9 cancer patients presenting with severe fluoropyrimidine-associated toxicity. All patients possessed a strongly reduced DPD activity, ranging from 9 to 53% of controls. Analysis of the DPD gene (DPYD) showed the presence of 21 variable sites including 4 novel and 4 very rare aberrations: 3 missense mutations, 2 splice-site mutations, 1 intronic mutation, a deletion of 21 nucleotides and a genomic amplification of exons 9-12. Two novel/rare variants (c.2843T>C, c.321+1G>A) were present in multiple, unrelated patients. Functional analysis of recombinantly-expressed DPD mutants carrying the p.I948T and p.G284V mutation showed residual DPD activities of 30% and 0.5%, respectively. Analysis of a DPD homology model indicated that the p.I948T and p.G284V mutations may affect electron transfer and the binding of FAD, respectively. cDNA analysis showed that the c.321+1G>A mutation in DPYD leads to skipping of exon 4 immediately upstream of the mutated splice-donor site in the process of DPD pre-mRNA splicing. A lethal toxicity in two DPD patients suggests that fluoropyrimidines combined with other therapies such as radiotherapy might be particularly toxic for DPD deficient patients. Our study advocates a more comprehensive genotyping approach combined with phenotyping strategies for upfront screening for DPD deficiency to ensure the safe administration of fluoropyrimidines.

  11. A DPYD variant (Y186C) in individuals of african ancestry is associated with reduced DPD enzyme activity.

    PubMed

    Offer, S M; Lee, A M; Mattison, L K; Fossum, C; Wegner, N J; Diasio, R B

    2013-07-01

    5-Fluorouracil (5-FU) is used to treat many aggressive cancers, such as those of the colon, breast, and head and neck. The responses to 5-FU, with respect to both toxicity and efficacy, vary among racial groups, potentially because of variability in the activity levels of the enzyme dihydropyrimidine dehydrogenase (DPD, encoded by the DPYD gene). In this study, the genetic associations between DPYD variations and circulating mononuclear-cell DPD enzyme activity were evaluated in 94 African-American and 81 European-American volunteers. The DPYD-Y186C variant was unique to individuals of African ancestry, and DPD activity was 46% lower in carriers as compared with noncarriers (279 ± 35 vs. 514 ± 168 pmol 5-FU min(-1) mg(-1); P = 0.00029). In this study, 26% of the African Americans with reduced DPD activity were carriers of Y186C. In the African-American cohort, after excluding Y186C carriers, homozygous carriers of C29R showed 27% higher DPD activity as compared with noncarriers (609 ± 152 and 480 ± 152 pmol 5-FU min(-1) mg(-1), respectively; P = 0.013).

  12. Modelling of thrombus growth in flow with a DPD-PDE method.

    PubMed

    Tosenberger, A; Ataullakhanov, F; Bessonov, N; Panteleev, M; Tokarev, A; Volpert, V

    2013-11-21

    Hemostatic plug covering the injury site (or a thrombus in the pathological case) is formed due to the complex interaction of aggregating platelets with biochemical reactions in plasma that participate in blood coagulation. The mechanisms that control clot growth and which lead to growth arrest are not yet completely understood. We model them with numerical simulations based on a hybrid DPD-PDE model. Dissipative particle dynamics (DPD) is used to model plasma flow with platelets while fibrin concentration is described by a simplified reaction-diffusion-advection equation. The model takes into account consecutive stages of clot growth. First, a platelet is weakly connected to the clot and after some time this connection becomes stronger due to other surface receptors involved in platelet adhesion. At the same time, the fibrin mesh is formed inside the clot. This becomes possible because flow does not penetrate the clot and cannot wash out the reactants participating in blood coagulation. Platelets covered by the fibrin mesh cannot attach new platelets. Modelling shows that the growth of a hemostatic plug can stop as a result of its exterior part being removed by the flow thus exposing its non-adhesive core to the flow. © 2013 Elsevier Ltd. All rights reserved.

  13. Parametric study on phase separation of binary mixtures in a lid driven cavity: A DPD study

    NASA Astrophysics Data System (ADS)

    Gidituri, Harinadha; Anand, Vijay; Panchagnula, Mahesh; Vedantam, Srikanth

    2016-11-01

    We investigate the phase separation behavior of binary mixtures in two dimensional periodic and lid driven cavity domains using dissipative particle dynamics (DPD). The effect of DPD parameters like repulsion coefficient, dissipative coefficient, cut-off radius, and weight function exponent on domain size growth has been studied. The phase separation is delayed for low values of repulsion coefficient. Under these conditions, a few clusters of the dispersed phase are distributed in a continuous phase. This is because of weak inter-particle repulsion. As we increase the repulsion coefficient value, this behavior disappears. The domain growth rate is also observed to increase with an increase in the value of the dissipation coefficient as well as cut-off radius. Finally, the dynamics of phase separation in the lid driven cavity problem are significantly different when compared to that in the periodic domain, due to the formation of a stable vortex in the cavity. The vortex results in a dynamic equilibrium between clustering and separation. The distribution of cluster sizes is studied as a function of the driven cavity parameters.

  14. Modelling of platelet-fibrin clot formation in flow with a DPD-PDE method.

    PubMed

    Tosenberger, A; Ataullakhanov, F; Bessonov, N; Panteleev, M; Tokarev, A; Volpert, V

    2016-02-01

    The paper is devoted to mathematical modelling of clot growth in blood flow. Great complexity of the hemostatic system dictates the need of usage of the mathematical models to understand its functioning in the normal and especially in pathological situations. In this work we investigate the interaction of blood flow, platelet aggregation and plasma coagulation. We develop a hybrid DPD-PDE model where dissipative particle dynamics (DPD) is used to model plasma flow and platelets, while the regulatory network of plasma coagulation is described by a system of partial differential equations. Modelling results confirm the potency of the scenario of clot growth where at the first stage of clot formation platelets form an aggregate due to weak inter-platelet connections and then due to their activation. This enables the formation of the fibrin net in the centre of the platelet aggregate where the flow velocity is significantly reduced. The fibrin net reinforces the clot and allows its further growth. When the clot becomes sufficiently large, it stops growing due to the narrowed vessel and the increase of flow shear rate at the surface of the clot. Its outer part is detached by the flow revealing the inner part covered by fibrin. This fibrin cap does not allow new platelets to attach at the high shear rate, and the clot stops growing. Dependence of the final clot size on wall shear rate and on other parameters is studied.

  15. Morphology and Performance of Polymer Solar Cell Characterized by DPD Simulation and Graph Theory

    NASA Astrophysics Data System (ADS)

    Du, Chunmiao; Ji, Yujin; Xue, Junwei; Hou, Tingjun; Tang, Jianxin; Lee, Shuit-Tong; Li, Youyong

    2015-11-01

    The morphology of active layers in the bulk heterojunction (BHJ) solar cells is critical to the performance of organic photovoltaics (OPV). Currently, there is limited information for the morphology from transmission electron microscopy (TEM) techniques. Meanwhile, there are limited approaches to predict the morphology /efficiency of OPV. Here we use Dissipative Particle Dynamics (DPD) to determine 3D morphology of BHJ solar cells and show DPD to be an efficient approach to predict the 3D morphology. Based on the 3D morphology, we estimate the performance indicator of BHJ solar cells by using graph theory. Specifically, we study poly (3-hexylthiophene)/[6, 6]-phenyl-C61butyric acid methyl ester (P3HT/PCBM) BHJ solar cells. We find that, when the volume fraction of PCBM is in the region 0.4 ∼ 0.5, P3HT/PCBM will show bi-continuous morphology and optimum performance, consistent with experimental results. Further, the optimum temperature (413 K) for the morphology and performance of P3HT/PCBM is in accord with annealing results. We find that solvent additive plays a critical role in the desolvation process of P3HT/PCBM BHJ solar cell. Our approach provides a direct method to predict dynamic 3D morphology and performance indicator for BHJ solar cells.

  16. Morphology and Performance of Polymer Solar Cell Characterized by DPD Simulation and Graph Theory

    PubMed Central

    Du, Chunmiao; Ji, Yujin; Xue, Junwei; Hou, Tingjun; Tang, Jianxin; Lee, Shuit-Tong; Li, Youyong

    2015-01-01

    The morphology of active layers in the bulk heterojunction (BHJ) solar cells is critical to the performance of organic photovoltaics (OPV). Currently, there is limited information for the morphology from transmission electron microscopy (TEM) techniques. Meanwhile, there are limited approaches to predict the morphology /efficiency of OPV. Here we use Dissipative Particle Dynamics (DPD) to determine 3D morphology of BHJ solar cells and show DPD to be an efficient approach to predict the 3D morphology. Based on the 3D morphology, we estimate the performance indicator of BHJ solar cells by using graph theory. Specifically, we study poly (3-hexylthiophene)/[6, 6]-phenyl-C61butyric acid methyl ester (P3HT/PCBM) BHJ solar cells. We find that, when the volume fraction of PCBM is in the region 0.4 ∼ 0.5, P3HT/PCBM will show bi-continuous morphology and optimum performance, consistent with experimental results. Further, the optimum temperature (413 K) for the morphology and performance of P3HT/PCBM is in accord with annealing results. We find that solvent additive plays a critical role in the desolvation process of P3HT/PCBM BHJ solar cell. Our approach provides a direct method to predict dynamic 3D morphology and performance indicator for BHJ solar cells. PMID:26581407

  17. DPD with effective pair potential from integral equation theory of molecular liquids

    NASA Astrophysics Data System (ADS)

    Kobryn, Alexander; Nikolić, Dragan; Lyubimova, Olga; Gusarov, Sergey; Kovalenko, Andriy

    2014-03-01

    A coarsening method of soft matter systems in solution is presented, in which the coarse grained (CG) force field is determined based on the statistical mechanical, integral equation theory of molecular liquids in interaction site representation, also known as reference interaction site model (RISM). Coarse graining is accomplished by a structure-matching procedure for solute CG beads without solvent that reproduces the corresponding distribution of all-atom solute in solvent obtained from RISM. Termed as an effective pair potential, the introduced potential of interaction between CG beads includes the effect of solvent and is used in dissipative particle dynamics (DPD) instead of the conservative force potential defined heuristically. It enables high flexibility in specifying the composition of solute CG beads and allows excluding solvent from explicit consideration in DPD. The suggested CG molecular model has been tested computationally and is shown to be a useful tool in investigating both structural and dynamic properties of polymer solutions and a promising platform for studies of macromolecular, supramolecular, and biomolecular systems in solution that require thermodynamic consistency, high accuracy, and computational efficiency. Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta T6G2G8, Canada.

  18. Final Project Report for DPD, Inc. Office Building in Lansing, Michigan

    SciTech Connect

    Deru, M.; Sherman, M.

    2003-03-01

    The National Renewable Energy Laboratory participated with DPD, Inc., in the thermal analysis of buildings constructed using concrete with recycled materials in the aggregate. This project was part of a Phase II Small Business Innovative Research grant to determine how the thermal properties of concrete can be''tuned'' for use in passive solar buildings. DPD Inc. and Michigan State University developed techniques to alter the thermal properties of concrete by introducing recycled materials into the aggregate. Two office/retail buildings were built in Lansing, Michigan for this research. The objective of NREL's involvement was to evaluate the effects of concrete thermal properties on the building performance through energy simulations and monitoring. This report presents a summary of work accomplished on this project, including a predesign analysis of the concrete properties and building designs as well as energy performance analysis after construction. The test results were used to calibrate computer models that were later used to predict long-term performance of the buildings.

  19. Morphology and Performance of Polymer Solar Cell Characterized by DPD Simulation and Graph Theory.

    PubMed

    Du, Chunmiao; Ji, Yujin; Xue, Junwei; Hou, Tingjun; Tang, Jianxin; Lee, Shuit-Tong; Li, Youyong

    2015-11-19

    The morphology of active layers in the bulk heterojunction (BHJ) solar cells is critical to the performance of organic photovoltaics (OPV). Currently, there is limited information for the morphology from transmission electron microscopy (TEM) techniques. Meanwhile, there are limited approaches to predict the morphology /efficiency of OPV. Here we use Dissipative Particle Dynamics (DPD) to determine 3D morphology of BHJ solar cells and show DPD to be an efficient approach to predict the 3D morphology. Based on the 3D morphology, we estimate the performance indicator of BHJ solar cells by using graph theory. Specifically, we study poly (3-hexylthiophene)/[6, 6]-phenyl-C61butyric acid methyl ester (P3HT/PCBM) BHJ solar cells. We find that, when the volume fraction of PCBM is in the region 0.4 ∼ 0.5, P3HT/PCBM will show bi-continuous morphology and optimum performance, consistent with experimental results. Further, the optimum temperature (413 K) for the morphology and performance of P3HT/PCBM is in accord with annealing results. We find that solvent additive plays a critical role in the desolvation process of P3HT/PCBM BHJ solar cell. Our approach provides a direct method to predict dynamic 3D morphology and performance indicator for BHJ solar cells.

  20. Relationship Between the DPD and TS mRNA Expression and the Response to S-1-Based Chemotherapy and Prognosis in Patients with Advanced Gastric Cancer.

    PubMed

    Shen, Xiao-Ming; Zhou, Chong; Lian, Lian; Li, Li-Qun; Li, Wei; Tao, Min

    2015-04-01

    The aim was to determine changes in dihydropyrimidine dehydrogenase (DPD) and thymidylate synthase (TS) mRNAs in the blood of advanced gastric cancer (AGC) patients to see whether these enzymes affected the patients' response to S-1-based chemotherapy and prognosis. For this purpose, pretreatment DPD/TS mRNA expressions were determined in 40 AGC patients using RT-PCR. The patients were then administered with S-1-based regimen (S-1 + cisplatin) and toxicities were recorded. The relationship between the DPD/TS mRNA expressions and the chemotherapy response, drug resistance, and prognosis was analyzed. The data show that DPD mRNA expression correlated significantly with Lauren type while TS mRNA expression correlated with distant metastasis. Patients with higher DPD and/or TS mRNA expression(s) showed poor response, while those with low DPD mRNA expression showed better response to the chemotherapy. Pooled analysis showed that the patients with low DPD/TS mRNA expressions had better therapeutic response. The incidence of bone marrow suppression, diarrhea, and oral mucositis was high in patients with low DPD mRNA expression. Median overall survival (OS) in 40 patients was 13.5 months. It was 17 months for low and 10 months for high DPD (P = 0.044) and TS mRNA expression (P = 0.047). Pooled analysis showed that the patients with both low DPD/TS mRNA expressions had longer OS (P = 0.001). In conclusion, the detection of DPD and/or TS mRNA expression can be used to predict the response to S-1-based chemotherapy, drug resistance, and prognosis in AGC patients as well as to help guide the individualized treatment of gastric cancer.

  1. A Proposal for Adopting the Frequency Response of an Envelope Amplifier with Memoryless DPD EER PA Model

    NASA Astrophysics Data System (ADS)

    Kato, Takayuki; Kogami, Yoshinori; Funahashi, Yuuki; Yamaoka, Atsushi; Yamaguchi, Keiichi; Tanabe, Yasuhiko; Zhou, Jiafeng; Morris, Kevin; T. Watkins, Gavin

    Recently, dynamic power supply voltage techniques, such as an Envelope Elimination and Restoration power amplifier (EER-PA) or Envelope-Tracking Power amplifier (ET-PA), have been attracting much attention because they can maintain high efficiency in large back-off region [1]-[6]. The dynamic power supply voltage techniques cause strong nonlinearity compared to a conventional power amplifier, hence a memoryless Digital Predistortion (DPD) technique is indispensable for these efficiency enhancement techniques. However, the performance of the memoryless DPD is degraded due to the frequency response of the envelope amplifier in the dynamic power supply voltage techniques [7]-[9]. In this paper, we clarify the degradation mechanisms of the memoryless DPD for the EER-PA due to the frequency response of the envelope amplifier based on the results of two-tone tests, and propose an analytical model for improving the performance of the memoryless DPD developed for the EER-PA. In addition, a prototype EER-PA is developed and we demonstrate that the residual distortion of the developed EER-PA with conventional memoryless DPD algorithm is compensated by the new algorithm based on the proposed analytical model. In the two-tone test, third-order intermodulation distortion (IMD3) with a tone spacing from 100kHz to 4MHz is improvement by up to 25dB by the memoryless DPD algorithm based on the proposed model. Measured adjacent channel leakage power ratio (ACPR) of the developed EER-PA is improved from -22.5dBc to -42.5dBc in the OFDM signal test with 1.08MHz bandwidth.

  2. High 99mTc-DPD myocardial uptake in a patient with apolipoprotein AI-related amyloidotic cardiomyopathy.

    PubMed

    Quarta, Candida Cristina; Obici, Laura; Guidalotti, Pier Luigi; Pieroni, Maurizio; Longhi, Simone; Perlini, Stefano; Verga, Laura; Merlini, Giampaolo; Rapezzi, Claudio

    2013-03-01

    Amyloidotic cardiomyopathy is still a widely underdiagnosed condition that usually requires endomyocardial biopsy (EMB) for a definite diagnosis. 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (99mTc-DPD) has proven highly sensitive for detecting amyloidotic cardiomyopathy due to transthyretin-related amyloid deposition. Herein we report the first description of the (99mTc-DPD scintigraphy profile in a patient with suspected amyloidotic cardiomyopathy and a final EMB- and genetically-proven diagnosis of familial apolipoprotein AI amyloidosis due to Leu174Ser variant.

  3. Disodium pentaborate decahydrate (DPD) induced apoptosis by decreasing hTERT enzyme activity and disrupting F-actin organization of prostate cancer cells.

    PubMed

    Korkmaz, Mehmet; Avcı, Cigir Biray; Gunduz, Cumhur; Aygunes, Duygu; Erbaykent-Tepedelen, Burcu

    2014-02-01

    Animal and cell culture studies have showed that boron and its derivatives may be promising anticancer agents in prostate cancer treatment. Thus, DU145 cells were treated with disodium pentaborate decahydrate (DPD) for 24, 48, and 72 h in order to investigate the inhibitor effect and mechanisms of DPD. Then, cell proliferation, telomerase enzyme activity, actin polymerization, and apoptosis were detected by WST-1 assay, qRT-PCR, immunofluorescence labeling, and flow cytometry, respectively. We found that DPD inhibited the growth of human prostate cancer cell line DU145 at the concentration of 3.5 mM for 24 h. Our results demonstrated that 7 mM of DPD treatment prevented the telomerase enzyme activity at the rate of 38 %. Furthermore, DPD has an apoptotic effect on DU145 cells which were examined by labeling DNA breaks. With 7 mM of DPD treatment, 8, 14, and 41 % of apoptotic cells were detected for 24, 48, and 72 h, respectively. Additionally, immunofluorescence labeling showed that the normal organization of actin filaments was disrupted in DPD-exposed cells, which is accompanied by the alteration of cell shape and by apoptosis in targeted cells. Taken together, the results indicate that DPD may exert its cytotoxicity at least partly by interfering with the dynamic properties of actin polymerization and decreasing the telomerase activity. Eventually, for the first time, the results of this study showed that DPD suppressed the activity of telomerase in DU145 cells, and therefore, we suggested that DPD could be an important agent for its therapeutic potential in the treatment of prostate cancer.

  4. A family of time-staggered schemes for integrating hybrid DPD models for polymers: Algorithms and applications

    SciTech Connect

    Symeonidis, Vasileios; Karniadakis, George Em . E-mail: gk@dam.brown.edu

    2006-10-10

    We propose new schemes for integrating the stochastic differential equations of dissipative particle dynamics (DPD) in simulations of dilute polymer solutions. The hybrid DPD models consist of hard potentials that describe the microscopic dynamics of polymers and soft potentials that describe the mesoscopic dynamics of the solvent. In particular, we develop extensions to the velocity-Verlet and Lowe's approaches - two representative DPD time-integrators - following a subcycling procedure whereby the solvent is advanced with a timestep much larger than the one employed in the polymer time-integration. The introduction of relaxation parameters allows optimization studies for accuracy while maintaining the low computational complexity of standard DPD algorithms. We demonstrate through equilibrium simulations that a 10-fold gain in efficiency can be obtained with the time-staggered algorithms without loss of accuracy compared to the non-staggered schemes. We then apply the new approach to investigate the scaling response of polymers in equilibrium as well as the dynamics of {lambda}-phage DNA molecules subjected to shear.

  5. A family of time-staggered schemes for integrating hybrid DPD models for polymers: Algorithms and applications

    NASA Astrophysics Data System (ADS)

    Symeonidis, Vasileios; Karniadakis, George Em

    2006-10-01

    We propose new schemes for integrating the stochastic differential equations of dissipative particle dynamics (DPD) in simulations of dilute polymer solutions. The hybrid DPD models consist of hard potentials that describe the microscopic dynamics of polymers and soft potentials that describe the mesoscopic dynamics of the solvent. In particular, we develop extensions to the velocity-Verlet and Lowe's approaches - two representative DPD time-integrators - following a subcycling procedure whereby the solvent is advanced with a timestep much larger than the one employed in the polymer time-integration. The introduction of relaxation parameters allows optimization studies for accuracy while maintaining the low computational complexity of standard DPD algorithms. We demonstrate through equilibrium simulations that a 10-fold gain in efficiency can be obtained with the time-staggered algorithms without loss of accuracy compared to the non-staggered schemes. We then apply the new approach to investigate the scaling response of polymers in equilibrium as well as the dynamics of λ-phage DNA molecules subjected to shear.

  6. Inhibition of quorum sensing and biofilm formation in Vibrio harveyi by 4-fluoro-DPD; a novel potent inhibitor of signalling.

    PubMed

    Kadirvel, Manikandan; Fanimarvasti, Fariba; Forbes, Sarah; McBain, Andrew; Gardiner, John M; Brown, Gavin D; Freeman, Sally

    2014-05-21

    (S)-4,5-Dihydroxypentane-2,3-dione [(S)-DPD, (1)] is a precursor for , a quorum sensing signalling molecule for inter- and intra-species bacterial communication. The synthesis of its fluoro-analogue, 4-fluoro-5-hydroxypentane-2,3-dione () is reported. An intermediate in this route also enables a new, shorter synthesis of the native (S)-DPD. 4-Fluoro-DPD (2) completely inhibited bioluminescence and bacterial growth of Vibrio harveyi BB170 strain at 12.5 μM and 100 μM, respectively.

  7. Spatially resolved simulations of membrane reactions and dynamics: Multipolar reaction DPD

    NASA Astrophysics Data System (ADS)

    Füchslin, R. M.; Maeke, T.; McCaskill, J. S.

    2009-08-01

    Biophysical chemistry of mesoscale systems and quantitative modeling in systems biology now require a simulation methodology unifying chemical reaction kinetics with essential collective physics. This will enable the study of the collective dynamics of complex chemical and structural systems in a spatially resolved manner with a combinatorially complex variety of different system constituents. In order to allow a direct link-up with experimental data (e.g. high-throughput fluorescence images) the simulations must be constructed locally, i.e. mesoscale phenomena have to emerge from local composition and interactions that can be extracted from experimental data. Under suitable conditions, the simulation of such local interactions must lead to processes such as vesicle budding, transport of membrane-bounded compartments and protein sorting, all of which result from a sophisticated interplay between chemical and mechanical processes and require the link-up of different length scales. In this work, we show that introducing multipolar interactions between particles in dissipative particle dynamics (DPD) leads to extended membrane structures emerging in a self-organized manner and exhibiting the necessary mechanical stability for transport, correct scaling behavior, and membrane fluidity so as to provide a two-dimensional self-organizing dynamic reaction environment for kinetic studies in the context of cell biology. Supplementary material in the form of video files available from the Journal web page at 10.1140/epje/i2009-10482-x and are accessible for authorised users. in here

  8. Revisiting AI-2 quorum sensing inhibitors: direct comparison of alkyl-DPD analogues and a natural product fimbrolide.

    PubMed

    Lowery, Colin A; Abe, Takumi; Park, Junguk; Eubanks, Lisa M; Sawada, Daisuke; Kaufmann, Gunnar F; Janda, Kim D

    2009-11-04

    Quorum sensing (QS) systems have been discovered in a wide variety of bacteria, and mediate both intra- and interspecies communication. The AI-2-based QS system represents the most studied of these proposed interspecies systems and has been shown to regulate diverse functions such as bioluminescence, expression of virulence factors, and biofilm formation. As such, the development of modulatory compounds, both agonists and antagonists, is of great interest for the study of unknown AI-2-based QS systems and the potential treatment of bacterial infections. The fimbrolide class of natural products has exhibited excellent inhibitory activity against AI-2-based QS and as such may be considered the "gold standard" of AI-2 inhibitors. Thus, we sought to include a fimbrolide as a control compound for our recently developed alkyl-DPD panel of AI-2 modulators. Herein, we present a revised synthesis of a commonly studied fimbrolide as well as a direct comparison between the fimbrolide and alkyl-DPD analogues. We demonstrate that our alkyl-DPD analogues are more potent inhibitors of QS in both Vibrio harveyi and Salmonella typhimurium, the two organisms with defined AI-2 QS systems, and in doing so call into question the widely accepted use of fimbrolide-derived compounds as the "gold standard" of AI-2 inhibition.

  9. Genotyping of a family with a novel deleterious DPYD mutation supports the pretherapeutic screening of DPD deficiency with dihydrouracil/uracil ratio.

    PubMed

    Thomas, F; Hennebelle, I; Delmas, C; Lochon, I; Dhelens, C; Garnier Tixidre, C; Bonadona, A; Penel, N; Goncalves, A; Delord, J P; Toulas, C; Chatelut, E

    2016-02-01

    Despite the growing evidence that dihydropyrimidine dehydrogenase deficiency (DPD, encoded by the DPYD gene) confers a higher risk of developing severe toxicity, most patients are not screened for DPD deficiency before fluoropyrimidine treatment. We report here the genetic and phenotypic analyses of DPD in a family related to a patient who died after a first cycle of 5-fluorouracil and in 15 additional retrospective patients having a partial DPD deficiency (as measured by plasma dihydrouracil/uracil ratio). The patient with lethal toxicity was found to be a compound heterozygote for two DPYD mutations: a novel 8-bp duplication (c.168_175dupGAATAATT, p.Phe59Ter) and c.1679T>G (Ile560Ser). The patient's dihydrouracil/uracil ratio indicates complete DPD deficiency. The novel mutation was found in two members of the patient's family. Deleterious DPYD mutations were identified in 9 out of the 15 patients. The relationship between genotype and dihydrouracil/uracil values in the 22 patients of the present study was significant (P = 0.01).

  10. Dissipative particle dynamics (DPD) simulations with fragment molecular orbital (FMO) based effective parameters for 1-Palmitoyl-2-oleoyl phosphatidyl choline (POPC) membrane

    NASA Astrophysics Data System (ADS)

    Doi, Hideo; Okuwaki, Koji; Mochizuki, Yuji; Ozawa, Taku; Yasuoka, Kenji

    2017-09-01

    In dissipative particle dynamics (DPD) simulations, it is necessary to use the so-called χ parameter set that express the effective interactions between particles. Recently, we have developed a new scheme to evaluate the χ parameters in a non-empirical way through a series of fragment molecular orbital (FMO) calculations. As a challenging test, we have performed the DPD simulations using the FMO-based χ parameters for a mixture of 1-Palmitoyl-2-oleoyl phosphatidyl choline (POPC) and water. The structures of both membrane and vesicle were formed successfully. The calculated structural parameters of membrane were in good agreement with experimental results.

  11. Effects of 1, 6-Bis[4-(4-amino-3-hydroxyphenoxy)phenyl]diamantane (DPD), a reactive oxygen species and apoptosis inducing agent, on human leukemia cells in vitro and in vivo

    SciTech Connect

    Chang, Y.F.; Chi, C.W.; Chern, Y.T.; Wang, J.J. . E-mail: ccwang@ntcn.edu.tw

    2005-01-01

    1, 6-Bis[4-(4-amino-3-hydroxyphenoxy)phenyl]diamantine (DPD), a new cytostatic and differentiation inducing agent, was found to inhibit the growth of several cancer cell lines in the National Cancer Institute (NCI) Anticancer Drug Screen system. Previously, we demonstrated that DPD inhibited the growth of human colon cancer cell lines both in vitro and in vivo. In this study, we examined the anticancer effects of DPD on two human leukemia cells lines. DPD exerted growth inhibitory activities in vitro against two human leukemia cell lines, the promyeloid line HL-60 and the lymphoblastic line Molt-3. The in vivo effect of tumor growth suppression by DPD was also observed in mouse xenografts. No acute toxicity was observed after an intra-peritoneal challenge of DPD in 'severe combined immune-deficiency' (SCID) mice twice a week. The in vitro study showed HL-60 was more sensitive to DPD than Molt-3 through induction of G{sub 0}/G{sub 1} cell-cycle arrest with the appearance of a hypodiploid DNA fraction. The increased superoxide (O{sub 2}{sup -}), dissipation of the mitochondrial membrane potential, activation of caspase 3, and increase in annexin V binding were evident before apoptosis in DPD-treated cells. The superoxide dismutase 1 (SOD1) mRNA expression was also decreased in DPD-treated HL-60 and Molt-3 cells. Thus, it appeared that inhibition of SOD might be the major cause for the production of cellular superoxide with concomitant decrease of H{sub 2}O{sub 2} in DPD-treated cells. Addition of antioxidant can reduce DPD-induced mitochondrial damage, caspase activation, and annexin V binding in HL-60 cells. The results suggest that the cellular generation of O{sub 2}{sup -} plays a role in initiating and coordinating DPD-mediated growth arrest and apoptosis of HL-60 cells. Importantly, addition of arsenic trioxide, a compound capable of reactive oxygen species (ROS) generation, significantly enhanced the in vitro activity of DPD. These results suggest that DPD

  12. MD/DPD Multiscale Framework for Predicting Morphology and Stresses of Red Blood Cells in Health and Disease.

    PubMed

    Chang, Hung-Yu; Li, Xuejin; Li, He; Karniadakis, George Em

    2016-10-01

    Healthy red blood cells (RBCs) have remarkable deformability, squeezing through narrow capillaries as small as 3 microns in diameter without any damage. However, in many hematological disorders the spectrin network and lipid bilayer of diseased RBCs may be significantly altered, leading to impaired functionality including loss of deformability. We employ a two-component whole-cell multiscale model to quantify the biomechanical characteristics of the healthy and diseased RBCs, including Plasmodium falciparum-infected RBCs (Pf-RBCs) and defective RBCs in hereditary disorders, such as spherocytosis and elliptocytosis. In particular, we develop a two-step multiscale framework based on coarse-grained molecular dynamics (CGMD) and dissipative particle dynamics (DPD) to predict the static and dynamic responses of RBCs subject to tensile forcing, using experimental information only on the structural defects in the lipid bilayer, cytoskeleton, and their interaction. We first employ CGMD on a small RBC patch to compute the shear modulus, bending stiffness, and network parameters, which are subsequently used as input to a whole-cell DPD model to predict the RBC shape and corresponding stress field. For Pf-RBCs at trophozoite and schizont stages, the presence of cytoadherent knobs elevates the shear response in the lipid bilayer and stiffens the RBC membrane. For RBCs in spherocytosis and elliptocytosis, the bilayer-cytoskeleton interaction is weakened, resulting in substantial increase of the tensile stress in the lipid bilayer. Furthermore, we investigate the transient behavior of stretching deformation and shape relaxation of the normal and defective RBCs. Different from the normal RBCs possessing high elasticity, our simulations reveal that the defective RBCs respond irreversibly, i.e., they lose their ability to recover the normal biconcave shape in successive loading cycles of stretching and relaxation. Our findings provide fundamental insights into the microstructure

  13. MD/DPD Multiscale Framework for Predicting Morphology and Stresses of Red Blood Cells in Health and Disease

    PubMed Central

    Chang, Hung-Yu; Li, Xuejin; Li, He; Karniadakis, George Em

    2016-01-01

    Healthy red blood cells (RBCs) have remarkable deformability, squeezing through narrow capillaries as small as 3 microns in diameter without any damage. However, in many hematological disorders the spectrin network and lipid bilayer of diseased RBCs may be significantly altered, leading to impaired functionality including loss of deformability. We employ a two-component whole-cell multiscale model to quantify the biomechanical characteristics of the healthy and diseased RBCs, including Plasmodium falciparum-infected RBCs (Pf-RBCs) and defective RBCs in hereditary disorders, such as spherocytosis and elliptocytosis. In particular, we develop a two-step multiscale framework based on coarse-grained molecular dynamics (CGMD) and dissipative particle dynamics (DPD) to predict the static and dynamic responses of RBCs subject to tensile forcing, using experimental information only on the structural defects in the lipid bilayer, cytoskeleton, and their interaction. We first employ CGMD on a small RBC patch to compute the shear modulus, bending stiffness, and network parameters, which are subsequently used as input to a whole-cell DPD model to predict the RBC shape and corresponding stress field. For Pf-RBCs at trophozoite and schizont stages, the presence of cytoadherent knobs elevates the shear response in the lipid bilayer and stiffens the RBC membrane. For RBCs in spherocytosis and elliptocytosis, the bilayer-cytoskeleton interaction is weakened, resulting in substantial increase of the tensile stress in the lipid bilayer. Furthermore, we investigate the transient behavior of stretching deformation and shape relaxation of the normal and defective RBCs. Different from the normal RBCs possessing high elasticity, our simulations reveal that the defective RBCs respond irreversibly, i.e., they lose their ability to recover the normal biconcave shape in successive loading cycles of stretching and relaxation. Our findings provide fundamental insights into the microstructure

  14. Interfacial tension in oil-water-surfactant systems: on the role of intra-molecular forces on interfacial tension values using DPD simulations.

    PubMed

    Deguillard, E; Pannacci, N; Creton, B; Rousseau, B

    2013-04-14

    We have computed interfacial tension in oil-water-surfactant model systems using dissipative particle dynamics (DPD) simulations. Oil and water molecules are modelled as single DPD beads, whereas surfactant molecules are composed of head and tail beads linked together by a harmonic potential to form a chain molecule. We have investigated the influence of the harmonic potential parameters, namely, the force constant K and the equilibrium distance r0, on the interfacial tension values. For both parameters, the range investigated has been chosen in agreement with typical values in the literature. Surprisingly, we observe a large effect on interfacial tension values, especially at large surfactant concentration. We demonstrate that, due to a subtle balance between intra-molecular and inter-molecular interactions, the local structure of surfactants at the oil-water interface is modified, the interfacial tension is changed and the interface stability is affected.

  15. Characteristic of core materials in polymeric micelles effect on their micellar properties studied by experimental and dpd simulation methods.

    PubMed

    Cheng, Furong; Guan, Xuewa; Cao, Huan; Su, Ting; Cao, Jun; Chen, Yuanwei; Cai, Mengtan; He, Bin; Gu, Zhongwei; Luo, Xianglin

    2015-08-15

    Polymeric micelles are one important class of nanoparticles for anticancer drug delivery, but the impact of hydrophobic segments on drug encapsulation and release is unclear, which deters the rationalization of drug encapsulation into polymeric micelles. This paper focused on studying the correlation between the characteristics of hydrophobic segments and encapsulation of structurally different drugs (DOX and β-carotene). Poly(ϵ-caprolactone) (PCL) or poly(l-lactide) (PLLA) were used as hydrophobic segments to synthesize micelle-forming amphiphilic block copolymers with the hydrophilic methoxy-poly(ethylene glycol) (mPEG). Both blank and drug loaded micelles were spherical in shape with sizes lower than 50 nm. PCL-based micelles exhibited higher drug loading capacity than their PLLA-based counterparts. Higher encapsulation efficiency of β-carotene was achieved compared with DOX. In addition, both doxorubicin and β-carotene were released much faster from PCL-based polymeric micelles. Dissipative particle dynamics (DPD) simulation revealed that the two drugs tended to aggregate in the core of the PCL-based micelles but disperse in the core of PLLA based micelles. In vitro cytotoxicity investigation of DOX loaded micelles demonstrated that a faster drug release warranted a more efficient cancer-killing effect. This research could serve as a guideline for the rational design of polymeric micelles for drug delivery.

  16. Viscous flow simulation in a stenosis model using discrete particle dynamics: a comparison between DPD and CFD.

    PubMed

    Feng, Rui; Xenos, Michalis; Girdhar, Gaurav; Kang, Wei; Davenport, James W; Deng, Yuefan; Bluestein, Danny

    2012-01-01

    Flow and stresses induced by blood flow acting on the blood cellular constituents can be represented to a certain extent by a continuum mechanics approach down to the order of the μm level. However, the molecular effects of, e.g., adhesion/aggregation bonds of blood clotting can be on the order of nm. The coupling of the disparate length and timescales between such molecular levels and macroscopic transport represents a major computational challenge. To address this challenge, a multiscale numerical approach based on discrete particle dynamics (DPD) methodology derived from molecular dynamics (MD) principles is proposed. The feasibility of the approach was firstly tested for its ability to simulate viscous flow conditions. Simulations were conducted in low Reynolds numbers flows (Re = 25-33) through constricted tubes representing blood vessels with various degrees of stenosis. Multiple discrete particles interacting with each other were simulated, with 1.24-1.36 million particles representing the flow domain and 0.4 million particles representing the vessel wall. The computation was carried out on the massive parallel supercomputer NY BlueGene/L employing NAMD-a parallel MD package for high performance computing (HPC). Typical recirculation zones were formed distal to the stenoses. The velocity profiles and recirculation zones were in excellent agreement with computational fluid dynamics (CFD) 3D Navier-Stokes viscous fluid flow simulations and with classic numerical and experimental results by YC Fung in constricted tubes. This feasibility analysis demonstrates the potential of a methodology that widely departs from a continuum approach to simulate multiscale phenomena such as flow induced blood clotting.

  17. Admittance to specialized palliative care (SPC) of patients with an assessed need: a study from the Danish palliative care database (DPD).

    PubMed

    Adsersen, Mathilde; Thygesen, Lau Caspar; Neergaard, Mette Asbjoern; Bonde Jensen, Anders; Sjøgren, Per; Damkier, Anette; Groenvold, Mogens

    2017-09-01

    Admittance to specialized palliative care (SPC) has been discussed in the literature, but previous studies examined exclusively those admitted, not those with an assessed need for SPC but not admitted. The aim was to investigate whether admittance to SPC for referred adult patients with cancer was related to sex, age, diagnosis, geographic region or referral unit. A register-based study with data from the Danish Palliative Care Database (DPD). From DPD we identified all adult patients with cancer, who died in 2010-2012 and who were referred to and assessed to have a need for SPC (N = 21,597).The associations were investigated using logistic regression models, which also evaluated whether time from referral to death influenced the associations. In the adjusted analysis, we found that admittance was higher for younger patients [e.g., 50-59 versus 80 + years: odds ratio (OR) = 2.03; 1.78-2.33]. There was lower odds of admittance for patients with hematological malignancies and patients from two regions: Capital Region of Denmark and Region of Southern Denmark. Lower admittance among men and patients referred from hospital departments was explained by later referral. In this first nationwide study of admittance to SPC among patients with a SPC need, we found difference in admittance according to age, diagnosis and region. This indicates that prioritization of the limited resources means that certain subgroups with a documented need have reduced likelihood of admission to SPC.

  18. Utility of (11)C-methionine and (11)C-donepezil for imaging of Staphylococcus aureus induced osteomyelitis in a juvenile porcine model: comparison to autologous (111)In-labelled leukocytes, (99m) Tc-DPD, and (18)F-FDG.

    PubMed

    Afzelius, Pia; Alstrup, Aage Ko; Schønheyder, Henrik C; Borghammer, Per; Jensen, Svend B; Bender, Dirk; Nielsen, Ole L

    2016-01-01

    The aim of this study was to compare (11)C-methionine and (11)C-donepezil positron emission tomography (PET) with (111)In-labeled leukocyte and (99m) Tc-DPD (Tc-99m 3,3-diphosphono-1,2-propanedicarboxylic acid) single-photon emission computed tomography (SPECT), and (18)F-fluorodeoxyglucose ((18)F-FDG) PET to improve detection of osteomyelitis. The tracers' diagnostic utility where tested in a juvenile porcine hematogenously induced osteomyelitis model comparable to osteomyelitis in children. Five 8-9 weeks old female domestic pigs were scanned seven days after intra-arterial inoculation in the right femoral artery with a porcine strain of Staphylococcus aureus. The sequential scan protocol included Computed Tomography, (11)C-methionine and (11)C-donepezil PET, (99m) Tc-DPD and (111)In-labelled leukocytes scintigraphy, and (18)F-FDG PET. This was followed by necropsy of the pigs and gross pathology, histopathology, and microbial examination. The pigs developed a total of 24 osteomyelitic lesions, 4 lesions characterized as contiguous abscesses and pulmonary abscesses (in two pigs). By comparing the 24 osteomyelitic lesions, (18)F-FDG accumulated in 100%, (111)In-leukocytes in 79%, (11)C-methionine in 79%, (11)C-donepezil in 58%, and (99m) Tc-DPD in none. Overall, (18)F-FDG PET was superior to (111)In-leukocyte SPECT and (11)C-methionine in marking infectious lesions.

  19. Utility of 11C-methionine and 11C-donepezil for imaging of Staphylococcus aureus induced osteomyelitis in a juvenile porcine model: comparison to autologous 111In-labelled leukocytes, 99mTc-DPD, and 18F-FDG

    PubMed Central

    Afzelius, Pia; Alstrup, Aage KO; Schønheyder, Henrik C; Borghammer, Per; Jensen, Svend B; Bender, Dirk; Nielsen, Ole L

    2016-01-01

    The aim of this study was to compare 11C-methionine and 11C-donepezil positron emission tomography (PET) with 111In-labeled leukocyte and 99mTc-DPD (Tc-99m 3,3-diphosphono-1,2-propanedicarboxylic acid) single-photon emission computed tomography (SPECT), and 18F-fluorodeoxyglucose (18F-FDG) PET to improve detection of osteomyelitis. The tracers’ diagnostic utility where tested in a juvenile porcine hematogenously induced osteomyelitis model comparable to osteomyelitis in children. Five 8-9 weeks old female domestic pigs were scanned seven days after intra-arterial inoculation in the right femoral artery with a porcine strain of Staphylococcus aureus. The sequential scan protocol included Computed Tomography, 11C-methionine and 11C-donepezil PET, 99mTc-DPD and 111In-labelled leukocytes scintigraphy, and 18F-FDG PET. This was followed by necropsy of the pigs and gross pathology, histopathology, and microbial examination. The pigs developed a total of 24 osteomyelitic lesions, 4 lesions characterized as contiguous abscesses and pulmonary abscesses (in two pigs). By comparing the 24 osteomyelitic lesions, 18F-FDG accumulated in 100%, 111In-leukocytes in 79%, 11C-methionine in 79%, 11C-donepezil in 58%, and 99mTc-DPD in none. Overall, 18F-FDG PET was superior to 111In-leukocyte SPECT and 11C-methionine in marking infectious lesions. PMID:28078182

  20. Polymer translocation through a nanopore: DPD study.

    PubMed

    Yang, Kan; Vishnyakov, Aleksey; Neimark, Alexander V

    2013-04-04

    Translocation of a polymer chain through a narrow pore is explored using 3D explicit solvent dissipative particle dynamics simulation. We study the dependence of the translocation dynamics and translocation time τ on the chain length N, driving force magnitude E, and solvent quality. Two types of driving forces are considered: uniform hydrostatic force, which is applied equally to the chain and solvent particles, and uniform electrostatic force, which is applied selectively to the charged particles in the chain and oppositely charged counterions in the solvent. We concluded that the scaling correlations τ ~ E(-ξ) and τ ~ N(β) are valid only for coil-like chains. For globular chains, the exponents ξ and β could not be identified with a reasonable accuracy. While the found value of ξ agrees with published experimental results and does not depend on the driving force type, the exponent β depends on the driving force and solvent quality. This is explained by nonequilibrium effects, as in the systems considered, the time of translocation is comparable with the time of chain relaxation. These effects, manifested in the changes of chain conformation in the process of translocation, were analyzed on the basis of the variation of the gyration radii of cis and trans segments of the chain in normal and lateral directions. A prominent chain expansion was observed for coils and was insignificant for globules. This work demonstrates the feasibility of the 3D dissipative particle dynamics modeling of translocation phenomena and accounting for the electrostatic interactions with explicit counterions, as well as for the solvent quality, in a computationally efficient manner.

  1. Salud mental en desastres naturales: estrategias interventivas con adultos mayores en sectores rurales de Chile.

    PubMed

    Osorio-Parraguez, Paulina; Espinoza, Adriana

    2016-06-01

    En el presente artículo se da a conocer una estrategia de intervención llevada a cabo con adultos mayores en la comuna de Paredones, sexta región de Chile, con posterioridad al terremoto y tsunami del 27 de febrero 2010 en Chile, en el contexto de una investigación sobre fortalezas y vulnerabilidades desplegadas por este grupo etario, con posterioridad a un desastre natural. Se presenta una descripción del desarrollo metodológico de la intervención y de los sustentos teóricos y conceptuales en los que se basa. Como resultado de este proceso, se propone una estrategia que trabaje a través de la identificación de las propias experiencias y fortalezas de los sujetos. De tal forma se minimizan los efectos negativos de los determinantes sociales de la salud (como la edad y el lugar de residencia) en contexto de crisis; permitiendo a los adultos mayores fortalecer sus recursos individuales y colectivos, en pro de su bienestar psicosocial.

  2. Clients with MMPI High D-PD: Therapy Implications.

    ERIC Educational Resources Information Center

    Anderson, Wayne; Bauer, Barbara

    1985-01-01

    Compared personal characteristics of 80 counseling clients with elevated 2-4 (Depression-Psychiatric Deviate) scales on their Minnesota Multiphasic Personality Inventory and 109 clients without elevations. Results indicated that clients with 2-4 elevations were significantly more depressed, had lower self-esteem, and were more likely to come from…

  3. Modeling Viscoelastic Properties of Triblock Copolymers: A DPD Simulation Study

    DTIC Science & Technology

    2009-08-01

    about 0.66 as the copolymer concentration, c , increases from 0.2 to 0.5; however, this increase is less significant at higher concentrations. The...0.40 to about 0.66 as the copolymer concentration, c , increases from 0.2 to 0.5; however, this increase is less significant at higher concentrations. The...is subjected to oscillatory strains, c , of frequency, x, the stress response, r, is necessarily cyclic and can be written Correspondence to: Y. R

  4. Estrategias educativas y de evaluación en la formación de médicos especialistas.

    PubMed

    Gaona-Flores, Verónica Alejandra; Campos-Navarro, Luz Arcelia; Arenas-Osuna, Jesús; Alcalá-Martínez, Enrique

    2017-01-01

    Las estrategias didácticas se han definido como procedimientos, medios o recursos que el docente utiliza para promover el aprendizaje significativo. Identificar las estrategias de enseñanza y de evaluación que utiliza el profesor con residentes en hospitales de tercer nivel de atención médica. Estudio transversal, con profesores de diversas especialidades, en el Centro Médico Nacional La Raza. Se aplicó un cuestionario que valora las estrategias utilizadas en la enseñanza y la evaluación. En una muestra de 90 profesores, 35 especialidades médicas con profesores ayudantes, adjuntos y titulares, las actividades de enseñanza que más realizan son organizar a los alumnos a exponer temas, seguido de realizar preguntas sobre temas vistos. Respecto a las estrategias educativas, la más frecuente fue análisis de casos y aprendizaje basado en problemas. Para evaluación del desempeño teórico, los métodos más utilizados fueron participación en clase, exposición de temas y exámenes. las actividades de enseñanza están basadas en la exposición de temas por los médicos residentes. La estrategia educativa más utilizada fue llevar a cabo análisis de casos clínicos, seguido por aprendizaje basado en problemas. La evaluación del desempeño en aspectos teóricos se realiza a partir de la participación en clase, la exposición de temas y exámenes. Teaching strategies have been defined as procedures, means or resources that teachers used to promote meaningful learning. Identify teaching strategies and evaluation used by the professor with residents in tertiary hospitals health care. This is a cross-sectional study conducted with full, associate and assistant professors of various medical specialties. A questionnaire was applied to evaluate the strategies used by professors to teach and evaluate students. We included a sample of 90 professors in 35 medical specialties. The most frequent teaching activities were: organizing students to develop presentations

  5. Estrategia innovadora enfocada en parejas del mismo sexo para disminuir la infección del VIH en hombres Latinos

    PubMed Central

    Martinez, Omar; Wu, Elwin; Sandfort, Theo; Shultz, Andrew Z.; Capote, Jonathan; Chávez, Silvia; Moya, Eva; Dodge, Brian; Morales, Gabriel; Porras, Antonio; Ovejero, Hugo

    2014-01-01

    Resumen El VIH es un problema de salud importante dentro de la comunidad latina de los Estados Unidos. Gracias a los esfuerzos de prevención, los niveles de contagio entre los latinos se han mantenido estables por más de una década. Sin embargo, esta población sigue siendo afectada a niveles muy altos, en particular entre hombres que tienen sexo con hombres (HSH), de origen latino y que hablan principalmente el idioma español. Existen varios factores que contribuyen a la transmisión del VIH entre esta población, como son: el uso de drogas; la violencia dentro de la pareja; la presencia de infecciones de transmisión sexual; relaciones sexuales sin protección, dentro y fuera de la pareja; el evadir la búsqueda de recursos (prueba y tratamiento adecuado) por temor a ser discriminado o por su estatus migratorio; la escasez de recursos económicos o estado de pobreza y los patrones relacionados a la migración. En particular, Investigaciones Epidemiológicas de Comportamientos han determinado: cómo algunas dinámicas en parejas están directamente asociadas a los comportamientos sexuales de riesgos. En consecuencia, es necesaria mayor investigación para identificar esas dinámicas, y a su vez, realizar intervenciones dirigidas a la reducción de conductas de riesgo enfocadas en parejas de hombres del mismo sexo. En este escrito, se describe la importancia del uso de las relaciones de pareja como estrategia en la reducción de la trasmisión del VIH/SIDA en HSH de origen latino y que hablan principalmente el idioma español en los Estados Unidos. PMID:25580466

  6. Pincharse sin infectarse: estrategias para prevenir la infección por el VIH y el VHC entre usuarios de drogas inyectables

    PubMed Central

    MATEU-GELABERT, P.; FRIEDMAN, S.; SANDOVAL, M.

    2011-01-01

    Resumen Objetivo Desde principios de los noventa, en la ciudad de Nueva York se han implementado con éxito programas para reducir la incidencia del virus de la inmunodeficiencia humana (VIH) y, en menor medida, del virus de la hepatitis C (VHC). A pesar de ello, aproximadamente el 70% de los usuario de drogas inyectables (UDI) están infectados por el VHC. Queremos investigar cómo el 30% restante se las ha arreglado para no infectarse. El Staying safe (nombre original del estudio) explora los comportamientos y mecanismos que ayudan a evitar la infección por el VHC y el VIH a largo plazo. Material y métodos Hemos utilizado el concepto de «desviación positiva» aplicado en otros campos de salud pública. Estudiamos las estrategias, prácticas y tácticas de prevención de aquellos UDI que, viviendo en contextos de alta prevalencia, se mantienen sin infectar por VIH y el VHC, a pesar de haberse inyectado heroína durante años. Los resultados preliminares presentados en este artículo incluyen el análisis de las entrevistas realizadas a 25 UDI (17 doble negativos, 3 doble positivos y 5 con infección por el VHC y sin infección por el VIH). Se usaron entrevistas semiestructuradas que exploraban con detalle la historia de vida de los sujetos, incluyendo su consumo de drogas, redes sociales, contacto con instituciones, relaciones sexuales y estrategias de protección y vigilancia. Resultados La intencionalidad es importante para no infectarse, especialmente durante períodos de involución (períodos donde hay un deterioro económico y/o social que llevan al que se inyecta a situaciones de mayor riesgo). Presentamos tres dimensiones independientes de intencionalidad que conllevan comportamientos que pueden ayudar a prevenir la infección: a) evitar «el mono» (síntomas de abstención) asegurando el acceso a la droga; b) «llevarlo bien» para no convertirse en un junkie y así evitar la «muerte social» y la falta de acceso a los recursos, y c) seguir sin

  7. Influence of surface modification of halloysite nanotubes on their dispersion in epoxy matrix: Mesoscopic DPD simulation

    NASA Astrophysics Data System (ADS)

    Komarov, P.; Markina, A.; Ivanov, V.

    2016-06-01

    The problems of constructing of a meso-scale model of composites based on polymers and aluminosilicate nanotubes for prediction of the filler's spatial distribution at early stages of material formation have been considered. As a test system for the polymer matrix, the mixture of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate as epoxy resin monomers and 4-methylhexahydrophthalic anhydride as curing agent has been used. It is shown that the structure of a mixture of uncured epoxy resin and nanotubes is (mainly) determined by the surface functionalization of nanotubes. The results indicate that only nanotubes with maximum functionalization can preserve a uniform distribution in space.

  8. LAMMPS Implementation of Constant Energy Dissipative Particle Dynamics (DPD-E)

    DTIC Science & Technology

    2014-03-01

    outline, the EOMs are formulated for the VV integration scheme under isoenergetic conditions. 1. For Ni ,...,1= a. ii’ pp ← b. iii t Fpp 2...4 b. iii t Fpp 2 ∆ +← , where ∑ ≠ ++= ij R ij D ij C iji FFFF c. i i ii m t prr ∆+← d. ∑ ≠ ∆ + ∆         −+← ij q ij Rq ij Dq ji ij...pppppppp 2. Deterministic Integration #1: For Ni ,...,1= a. Ciii t Fpp 2 ∆ +← b. i i ii m t prr ∆+← 3. Conservative Force Calculation

  9. Space station MSFC-DPD-235/DR no. CM-02 specification, space station project (modular)

    NASA Technical Reports Server (NTRS)

    Smith, T. D.

    1971-01-01

    The orbiting laboratory which can take many forms and can be configured to house a crew of up to 12 men is discussed. The initial study of the 33-foot-diameter Space Station, launched by the Saturn INT-21 and supporting a complement of 12 crewmen, has been completed and documented. A Modular Space Station comprised of smaller, shuttle-launched modules is described. These modules could ultimately be configured to provide for a crew of the same size as envisioned for the 33-foot-diameter Space Station-but buildup would be gradual, beginning with a small initial crew and progressing toward greater capability by adding modules and crewmen on a flexible schedule.

  10. Space station MSFC-DPD-235/DR no. CM-04 interface and support requirements

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The interface and support performance, design and confirmation requirements are defined for the modular space station and space shuttle programs. The requirements are treated as separate obligations against each modular program and are presented for the following: shuttle orbiter, shuttle booster, launch operations, mission operations, and the research applications module.

  11. Thermostatic and rheological responses of DPD fluid to extreme shear under modified Lees-Edwards boundary condition.

    PubMed

    Moshfegh, Abouzar; Ahmadi, Goodarz; Jabbarzadeh, Ahmad

    2015-12-01

    Thermodynamic, hydrodynamic and rheological interactions between velocity-dependent thermostats of Lowe-Andersen (LA) and Nosé-Hoover-Lowe-Andersen (NHLA), and modified Lees-Edwards (M-LEC) boundary condition were studied in the context of Dissipative Particle Dynamics method. Comparisons were made with original Lees-Edwards method to characterise the improvements that M-LEC offers in conserving the induced shear momentum. Different imposed shear velocities, heat bath collision/exchange frequencies and thermostating probabilities were considered. The presented analyses addressed an unusual discontinuity in momentum transfer that appeared in form of nonphysical jumps in velocity and temperature profiles. The usefulness of M-LEC was then quantified by evaluating the enhancements in obtained effective shear velocity, effective shear rate, Péclet number, and dynamic viscosity. System exchange frequency (Γ) with Maxwellian heat bath was found to play an important role, in that its larger values facilitated achieving higher shear rates with proper temperature control at the cost of deviation from an ideal momentum transfer. Similar dynamic viscosities were obtained under both shearing modes between LA and NHLA thermostats up to Γ = 10, whilst about twice the range of viscosity (1 < η < 20) was calculated for M-LEC at larger probabilities (ΓΔt > %). The main benefits of this modification were to facilitate momentum flow from shear boundaries to the system bulk. In addition, it was found that there exist upper thresholds for imposing shear on the system beyond which temperature cannot be controlled properly and nonphysical jumps reappear.

  12. /sup 99m/Tc-DPD uptake in juvenile hemarthrosis. Scintimetry and autoradiography of the knee in dogs

    SciTech Connect

    Hansen, E.S.; Hjortdal, V.E.; Noer, I.; Christensen, S.B.; Holm, I.E.; Buenger, C.

    1989-03-01

    The pathogenesis of subchondral bone lesions and growth plate affection in hemophilic arthropathy was studied in puppies by means of repeated regional /sup 99m/Tc-diphosphonate scintimetry and contact autoradiography. Unilateral hemarthrosis of the knee was induced by biweekly intraarticular injections of autologous blood for 12 weeks. Hemarthrosis caused an early (2 to 4 weeks) decrease in uptake of /sup 99m/Tc-diphosphonate in the juxtaarticular growth plates (ratio 0.7) and a delayed (8 to 10 weeks) increase in epiphyseal uptake (ratio 1.5). In a recovery phase after hemarthrosis, growth plate uptake returned to normal, while the epiphyseal uptake remained elevated for 8 to 10 weeks. By contact autoradiography, the growth plate uptake was localized to the calcification layer at the metaphyseal aspect of the growth plates, while the epiphyseal uptake mainly was seen in the thin subchondral and subsynovial bone layer and around osteophytes. The changes in uptake of /sup 99m/Tc-diphosphonate following hemarthrosis for 3 months were reversible and could be ascribed to the presence of synovial inflammation.

  13. Space station MSFC-DPD-235/DR no. CM-03 specification, modular space station project, Part 1 CEI

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Contract engineering item specifications for the modular space station are presented. These specifications resulted from the development and allocations of requirements which are concise statements of performance or constraints on performance. Specifications contain requirements for functional performance and for the verification of design solutions.

  14. Space station MSFC-DPD-235/DR no. MA-05 phase C/D program development plan. Volume 2: Phase C/D, programmatic requirements

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The design plan requirements define the design implementation and control requirements for Phase C/D of the Modular Space Station Project and specifically address the Initial Space Station phase of the Space Station Program (modular). It is based primarily on the specific objective of translating the requirements of the Space Station Program, Project, Interface, and Support Requirements and preliminary contract end x item specifications into detail design of the operational systems which comprise the initial space station. This document is designed to guide aerospace contractors in the planning and bidding for Phase C/D.

  15. Clasificación de asterismos utilizando datos astrométricos

    NASA Astrophysics Data System (ADS)

    de Biasi, M. S.; Orellana, R. B.

    Based on accurate positions and proper motion data up to faint magnitudes, we have studied the regions of twenty three objects known in the literature as asterisms. A parametric method was applied to confirm the nature of these objects. The following objects have been classified: Alessi 11, Alessi 17, Brosch 1, Collinder 21, Dol-Dzim 1, Dolidze 31, Dolidze 43, Dolidze 50, Dolidze 51, NGC 272, NGC2063, NGC 2413, NGC 2664, NGC 5155, NGC 5284, NGC 6222, NGC 6360, NGC 6447, NGC 6476, NGC 6480, NGC 6605, NGC 6659, NGC 6728. FULL TEXT IN SPANISH

  16. Tratamiento de mostos utilizando el filtro anaerobio (treatment of must using an anaerobic filter). Master thesis

    SciTech Connect

    Negron, R.M.

    1982-12-01

    This study reports on the feasibility of treating the slops from rum distilleries with an anaerobic filter composed of an oxygen free reactor filled with a plastic filtering media, commercially known as 'Actifil' with a diameter of 5/8 inches (16mm). This filter is similar in appearance to an aerobic biofilter (trickling filter). The main difference between the two systems is that on the anaerobic filter the flow is upward so that the filter medium is always completely submerged.

  17. Urinary deoxypyridinoline excretion for the evaluation of bone turnover in chronic renal failure.

    PubMed

    Coen, G; Mantella, D; Calabria, S; Sardella, D; Manni, M; Fassino, V; D'Anello, E; Giustini, M; Taggi, F

    2000-01-01

    The urinary excretion of deoxypyridinoline (DPD) was evaluated in predialysis chronic renal failure (CRF), together with intact PTH and several classic markers of bone turnover in order to assess whether urine free and total DPD excretion are equivalent parameters of bone turnover in CRF, and to evaluate the relationship between urine DPD excretion, PTH and the other bone markers. The study was carried out in 94 patients with different degrees of renal failure due to various kidney diseases. Besides urinary DPD expressed as free DPD, total DPD, free/total DPD, free DPD/Cr and total DPD/Cr, the following determinations were made: intact PTH, bone alkaline phosphatase (BALP), total alkaline phosphatase (AP), osteocalcin (BGP), serum C-terminal telopeptide of collagen type I (ICTP) and hydroxyproline (OHpro). The patients were divided into 3 groups according to the increasing severity of renal failure (Ccr >40, 40-20, <20 ml/min). The ratio free/total DPD decreased (NS) with advancing renal failure, and was inversely correlated with total DPD excretion. While PTH increased progressively to about four times the values observed in the Ccr >40 group, there was a parallel increase only in BGP and ICTP, parameters retained in the serum with decreasing renal function, while AP, BALP, total DPD and OHpro did not change. However, significant correlations between total DPD/Cr and PTH, BALP, BGP and ICTP were also found. In CRF free DPD is an unreliable index of bone turnover due to a probable interference in its production from the peptide-bound DPD. Total DPD or total DPD/Cr are better used. In spite of the significant correlations observed in advanced renal failure between PTH and most of the parameters examined, a resistance of bone tissue to PTH action in CRF must be considered. Copyright 2000 S. Karger AG, Basel

  18. 40 CFR 142.16 - Special primacy requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...)—Approve DPD colorimetric test kits for free and combined chlorine measurement or approve calibration of... test kits). Approve DPD colorimetric test kits for free and total chlorine measurements. State approval granted under § 141.74(a)(2) of this chapter for the use of DPD colorimetric test kits for free...

  19. 40 CFR 142.16 - Special primacy requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...)—Approve DPD colorimetric test kits for free and combined chlorine measurement or approve calibration of... test kits). Approve DPD colorimetric test kits for free and total chlorine measurements. State approval granted under § 141.74(a)(2) of this chapter for the use of DPD colorimetric test kits for free...

  20. 40 CFR 142.16 - Special primacy requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...)—Approve DPD colorimetric test kits for free and combined chlorine measurement or approve calibration of... test kits). Approve DPD colorimetric test kits for free and total chlorine measurements. State approval granted under § 141.74(a)(2) of this chapter for the use of DPD colorimetric test kits for free...

  1. Transport dissipative particle dynamics model for mesoscopic advection- diffusion-reaction problems

    SciTech Connect

    Zhen, Li; Yazdani, Alireza; Tartakovsky, Alexandre M.; Karniadakis, George E.

    2015-07-07

    We present a transport dissipative particle dynamics (tDPD) model for simulating mesoscopic problems involving advection-diffusion-reaction (ADR) processes, along with a methodology for implementation of the correct Dirichlet and Neumann boundary conditions in tDPD simulations. tDPD is an extension of the classic DPD framework with extra variables for describing the evolution of concentration fields. The transport of concentration is modeled by a Fickian flux and a random flux between particles, and an analytical formula is proposed to relate the mesoscopic concentration friction to the effective diffusion coefficient. To validate the present tDPD model and the boundary conditions, we perform three tDPD simulations of one-dimensional diffusion with different boundary conditions, and the results show excellent agreement with the theoretical solutions. We also performed two-dimensional simulations of ADR systems and the tDPD simulations agree well with the results obtained by the spectral element method. Finally, we present an application of the tDPD model to the dynamic process of blood coagulation involving 25 reacting species in order to demonstrate the potential of tDPD in simulating biological dynamics at the mesoscale. We find that the tDPD solution of this comprehensive 25-species coagulation model is only twice as computationally expensive as the DPD simulation of the hydrodynamics only, which is a significant advantage over available continuum solvers.

  2. Mapping of dissipative particle dynamics in fluctuating hydrodynamics simulations

    NASA Astrophysics Data System (ADS)

    Qiao, R.; He, P.

    2008-03-01

    Dissipative particle dynamics (DPD) is a novel particle method for mesoscale modeling of complex fluids. DPD particles are often thought to represent packets of real atoms, and the physical scale probed in DPD models are determined by the mapping of DPD variables to the corresponding physical quantities. However, the nonuniqueness of such mapping has led to difficulties in setting up simulations to mimic real systems and in interpreting results. For modeling transport phenomena, where thermal fluctuations are important (e.g., fluctuating hydrodynamics), an area particularly suited for DPD method, we propose that DPD fluid particles should be viewed as only (1) to provide a medium in which the momentum and energy are transferred according to the hydrodynamic laws and (2) to provide objects immersed in the DPD fluids the proper random "kicks" such that these objects exhibit correct fluctuation behaviors at the macroscopic scale. We show that, in such a case, the choice of system temperature and mapping of DPD scales to physical scales are uniquely determined by the level of coarse graining and properties of DPD fluids. We also verified that DPD simulation can reproduce the macroscopic effects of thermal fluctuation in particulate suspension by showing that the Brownian diffusion of solid particles can be computed in DPD simulations with good accuracy.

  3. An extended dissipative particle dynamics model

    NASA Astrophysics Data System (ADS)

    Cotter, C. J.; Reich, S.

    2003-12-01

    The method of dissipative particle dynamics (DPD) was introduced by Hoogerbrugge and Koelman (Europhys. Lett., 19 (1992) 155) to study meso-scale material processes. The theoretical investigation of the DPD method was initiated by Espanol (Phys. Rev. E, 52 (1995) 1734) who used a Fokker-Planck formulation of the DPD method and applied the Mori-Zwanzig projection operator calculus to obtain the equations of hydrodynamics for DPD. A current limitation of DPD is that it requires a clear separation of scales between the resolved and unresolved processes. In this letter, we suggest a simple extension of DPD that allows for inclusion of unresolved stochastic processes with exponentially decaying variance for any value of the decay rate, and give an application of this algorithm to the simulation of the shallow-water equations using the Hamiltonian particle-mesh method. The proposed extension is as easy to implement as the standard DPD methods.

  4. Natural convection heat transfer simulation using energy conservative dissipative particle dynamics.

    PubMed

    Abu-Nada, Eiyad

    2010-05-01

    Dissipative particle dynamics with energy conservation (eDPD) was used to study natural convection via Rayleigh-Bénard (RB) problem and a differentially heated enclosure problem (DHE). The current eDPD model implemented the Boussinesq approximation to model the buoyancy forces. The eDPD results were compared to the finite volume solutions and it was found that the eDPD method predict the temperature and flow fields throughout the natural convection domains properly. The eDPD model recovered the basic features of natural convection, such as development of plumes, development of thermal boundary layers, and development of natural convection circulation cells (rolls). The eDPD results were presented via temperature isotherms, streamlines, velocity contours, velocity vector plots, and temperature and velocity profiles. Further useful quantities, such as Nusselt number was calculated from the eDPD results and found to be in good agreement with the finite volume calculations.

  5. The New Room Arrangement as a Teaching Strategy = La Nueva Organizacion del Salon como Estrategia Educativa.

    ERIC Educational Resources Information Center

    Dodge, Diane Trister

    Many typical classroom behavior problems--running in the classroom, inability to make choices, failure to stick with activities, fighting over toys, and poor use of materials-- can be traced to how the room is arranged and how materials are displayed. By making a few changes in the classroom environment, early childhood teachers can create a…

  6. The New Room Arrangement as a Teaching Strategy = La Nueva Organizacion del Salon como Estrategia Educativa.

    ERIC Educational Resources Information Center

    Dodge, Diane Trister

    Many typical classroom behavior problems--running in the classroom, inability to make choices, failure to stick with activities, fighting over toys, and poor use of materials-- can be traced to how the room is arranged and how materials are displayed. By making a few changes in the classroom environment, early childhood teachers can create a…

  7. ESTRATEGIAS PARA HACER EL MEJOR USO DE LA PROTEINA EN RACIONES PARA VACAS LECHERAS

    USDA-ARS?s Scientific Manuscript database

    Dairy cows utilize feed CP with greater efficiency than other ruminants, but still excrete about 2 to 3 times more N in manure than they secrete in milk. This increases milk production costs plus environmental N pollution. Optimizing microbial protein formation in the rumen is the most effective way...

  8. Las estrategias de un lider (The Strategies of a Leader). ERIC Digest.

    ERIC Educational Resources Information Center

    Lashway, Larry

    A decade ago, principals were asked to become instructional leaders who exercised firm control by setting goals, maintaining discipline, and evaluating results. Today, they are encouraged to act as facilitative leaders by building teams, creating networks, and "governing from the center." Rapid shifts in administrative philosophy can be…

  9. Hacia la predicción del Número R de Wolf de manchas solares utilizando Redes Neuronales con retardos temporales

    NASA Astrophysics Data System (ADS)

    Francile, C.; Luoni, M. L.

    We present a prediction of the time series of the Wolf number R of sunspots using "time lagged feed forward neural networks". We use two types of networks: the focused and distributed ones which were trained with the back propagation of errors algorithm and the temporal back propagation algorithm respectively. As inputs to neural networks we use the time series of the number R averaged annually and monthly with the method IR5. As data sets for training and test we choose certain intervals of the time series similar to other works, in order to compare the results. Finally we discuss the topology of the networks used, the number of delays used, the number of neurons per layer, the number of hidden layers and the results in the prediction of the series between one and six steps ahead. FULL TEXT IN SPANISH

  10. Actividad solar del ciclo 23. Predicción del máximo y fase decreciente utilizando redes neuronales

    NASA Astrophysics Data System (ADS)

    Parodi, M. A.; Ceccatto, H. A.; Piacentini, R. D.; García, P. J.

    Different methods have been proposed in order to predict the maximum amplitude of solar cycles, either as a consequence of the intrinsic importance of this event and because of its relation with solar storms and possible effects upon satellites, communication systems, etc. In this work, a neural network solar activity prediction is presented, measured through the sunspot number (SSN). The 16-units neural network, with a 12:3:1 architecture, was trained in a ``feed-forward" propagation way and learning by the so called ``back propagation rule". The annual mean SSN data in the 1700-1975 and 1987-1998 periods were used as the training set. The solar cycle 21 (1976-1986) was taken as the cross-validation data set. After performing the network training we obtained a prediction of the maximum annual mean for the current solar cycle 23, SSNmax= 135 ±17 at the year 2000, which is 13% smaller than the International Consensus Commitee's mean maximum prediction obtained through ``precursor techniques". On the other hand, our prediction is only about 4% smaller than the Consensus's neural network mean prediction. A ``multiple step" prediction technique was also performed and SSN annual mean predicted values for the near-maximum (from the present year 1999 to beyond the maximum) and the declining activity of solar cycle 23 are presented in this work. The sensibility of predictions is also tested. To do so, we changed the interval width and comparated our results with those of a previous neural network prediction and those of others authors using differents methods.

  11. Estudio numerico y experimental del proceso de soldeo MIG sobre la aleacion 6063--T5 utilizando el metodo de Taguchi

    NASA Astrophysics Data System (ADS)

    Meseguer Valdenebro, Jose Luis

    Electric arc welding processes represent one of the most used techniques on manufacturing processes of mechanical components in modern industry. The electric arc welding processes have been adapted to current needs, becoming a flexible and versatile way to manufacture. Numerical results in the welding process are validated experimentally. The main numerical methods most commonly used today are three: finite difference method, finite element method and finite volume method. The most widely used numerical method for the modeling of welded joints is the finite element method because it is well adapted to the geometric and boundary conditions in addition to the fact that there is a variety of commercial programs which use the finite element method as a calculation basis. The content of this thesis shows an experimental study of a welded joint conducted by means of the MIG welding process of aluminum alloy 6063-T5. The numerical process is validated experimentally by applying the method of finite element through the calculation program ANSYS. The experimental results in this paper are the cooling curves, the critical cooling time t4/3, the weld bead geometry, the microhardness obtained in the welded joint, and the metal heat affected zone base, process dilution, critical areas intersected between the cooling curves and the curve TTP. The numerical results obtained in this thesis are: the thermal cycle curves, which represent both the heating to maximum temperature and subsequent cooling. The critical cooling time t4/3 and thermal efficiency of the process are calculated and the bead geometry obtained experimentally is represented. The heat affected zone is obtained by differentiating the zones that are found at different temperatures, the critical areas intersected between the cooling curves and the TTP curve. In order to conclude this doctoral thesis, an optimization has been conducted by means of the Taguchi method for welding parameters in order to obtain an improvement on mechanical properties in aluminum metal joint. Los procesos de soldadura por arco electrico representan unas de las tecnicas mas utilizadas en los procesos de fabricacion de componentes mecanicos en la industria moderna. Los procesos de soldeo por arco se han adaptado a las necesidades actuales, haciendose un modo de fabricacion flexible y versatil. Los resultados obtenidos numericamente en el proceso de soldadura son validados experimentalmente. Los principales metodos numericos mas empleados en la actualidad son tres, metodo por diferencias finitas, metodos por elementos finitos y metodo por volumenes finitos. El metodo numerico mas empleado para el modelado de uniones soldadas, es el metodo por elementos finitos, debido a que presenta una buena adaptacion a las condiciones geometricas y de contorno ademas de que existe una diversidad de programas comerciales que utilizan el metodo por elementos finitos como base de calculo. Este trabajo de investigacion presenta un estudio experimental de una union soldada mediante el proceso MIG de la aleacion de aluminio 6063-T5. El metodo numerico se valida experimentalmente aplicando el metodo de los elementos finitos con el programa de calculo ANSYS. Los resultados experimentales obtenidos son: las curvas de enfriamiento, el tiempo critico de enfriamiento t4/3, geometria del cordon, microdurezas obtenidas en la union soldada, zona afectada termicamente y metal base, dilucion del proceso, areas criticas intersecadas entre las curvas de enfriamiento y la curva TTP. Los resultados numericos son: las curvas del ciclo termico, que representan tanto el calentamiento hasta alcanzar la temperatura maxima y un posterior enfriamiento. Se calculan el tiempo critico de enfriamiento t4/3, el rendimiento termico y se representa la geometria del cordon obtenida experimentalmente. La zona afectada termicamente se obtiene diferenciando las zonas que se encuentran a diferentes temperaturas, las areas criticas intersecadas entre las curvas de enfriamiento y la curva TTP. Para finalizar el trabajo de investigacion se ha realizado una optimizacion, con la aplicacion del metodo de Taguchi, de los parametros de soldeo con el objetivo de obtener una mejora sustancial en las propiedades mecanicas de las uniones metalicas de aluminio.

  12. Transport dissipative particle dynamics model for mesoscopic advection-diffusion-reaction problems

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Yazdani, Alireza; Tartakovsky, Alexandre; Karniadakis, George Em

    2015-07-01

    We present a transport dissipative particle dynamics (tDPD) model for simulating mesoscopic problems involving advection-diffusion-reaction (ADR) processes, along with a methodology for implementation of the correct Dirichlet and Neumann boundary conditions in tDPD simulations. tDPD is an extension of the classic dissipative particle dynamics (DPD) framework with extra variables for describing the evolution of concentration fields. The transport of concentration is modeled by a Fickian flux and a random flux between tDPD particles, and the advection is implicitly considered by the movements of these Lagrangian particles. An analytical formula is proposed to relate the tDPD parameters to the effective diffusion coefficient. To validate the present tDPD model and the boundary conditions, we perform three tDPD simulations of one-dimensional diffusion with different boundary conditions, and the results show excellent agreement with the theoretical solutions. We also performed two-dimensional simulations of ADR systems and the tDPD simulations agree well with the results obtained by the spectral element method. Finally, we present an application of the tDPD model to the dynamic process of blood coagulation involving 25 reacting species in order to demonstrate the potential of tDPD in simulating biological dynamics at the mesoscale. We find that the tDPD solution of this comprehensive 25-species coagulation model is only twice as computationally expensive as the conventional DPD simulation of the hydrodynamics only, which is a significant advantage over available continuum solvers.

  13. Transport dissipative particle dynamics model for mesoscopic advection-diffusion-reaction problems

    PubMed Central

    Yazdani, Alireza; Tartakovsky, Alexandre; Karniadakis, George Em

    2015-01-01

    We present a transport dissipative particle dynamics (tDPD) model for simulating mesoscopic problems involving advection-diffusion-reaction (ADR) processes, along with a methodology for implementation of the correct Dirichlet and Neumann boundary conditions in tDPD simulations. tDPD is an extension of the classic dissipative particle dynamics (DPD) framework with extra variables for describing the evolution of concentration fields. The transport of concentration is modeled by a Fickian flux and a random flux between tDPD particles, and the advection is implicitly considered by the movements of these Lagrangian particles. An analytical formula is proposed to relate the tDPD parameters to the effective diffusion coefficient. To validate the present tDPD model and the boundary conditions, we perform three tDPD simulations of one-dimensional diffusion with different boundary conditions, and the results show excellent agreement with the theoretical solutions. We also performed two-dimensional simulations of ADR systems and the tDPD simulations agree well with the results obtained by the spectral element method. Finally, we present an application of the tDPD model to the dynamic process of blood coagulation involving 25 reacting species in order to demonstrate the potential of tDPD in simulating biological dynamics at the mesoscale. We find that the tDPD solution of this comprehensive 25-species coagulation model is only twice as computationally expensive as the conventional DPD simulation of the hydrodynamics only, which is a significant advantage over available continuum solvers. PMID:26156459

  14. Dissipative particle dynamics of diffusion-NMR requires high Schmidt-numbers

    NASA Astrophysics Data System (ADS)

    Azhar, Mueed; Greiner, Andreas; Korvink, Jan G.; Kauzlarić, David

    2016-06-01

    We present an efficient mesoscale model to simulate the diffusion measurement with nuclear magnetic resonance (NMR). On the level of mesoscopic thermal motion of fluid particles, we couple the Bloch equations with dissipative particle dynamics (DPD). Thereby we establish a physically consistent scaling relation between the diffusion constant measured for DPD-particles and the diffusion constant of a real fluid. The latter is based on a splitting into a centre-of-mass contribution represented by DPD, and an internal contribution which is not resolved in the DPD-level of description. As a consequence, simulating the centre-of-mass contribution with DPD requires high Schmidt numbers. After a verification for fundamental pulse sequences, we apply the NMR-DPD method to NMR diffusion measurements of anisotropic fluids, and of fluids restricted by walls of microfluidic channels. For the latter, the free diffusion and the localisation regime are considered.

  15. Logistics Civil Augmentation Program Support Contract Needs to Comply With Acquisition Rules

    DTIC Science & Technology

    2011-01-07

    The LOGCAP DPD office in Kuwait assumed responsibility for assisting with developing more than $ 1 billion in annual requirements after the operations...The non- LOGCAP requirements were supported by 12 of 13 LOGCAP support contractor employees in the LOGCAP DPD office in Kuwait; only 1 LOGCAP...specialists, 3 cost analysts, and 1 administrative specialist. RICC personnel exercised Option Year 3 in February 2010, and definitized DPD support

  16. Phenotypic and clinical implications of variants in the dihydropyrimidine dehydrogenase gene.

    PubMed

    Kuilenburg, André B P van; Meijer, Judith; Tanck, Michael W T; Dobritzsch, Doreen; Zoetekouw, Lida; Dekkers, Lois-Lee; Roelofsen, Jeroen; Meinsma, Rutger; Wymenga, Machteld; Kulik, Wim; Büchel, Barbara; Hennekam, Raoul C M; Largiadèr, Carlo R

    2016-04-01

    Dihydropyrimidine dehydrogenase (DPD) is the initial and rate-limiting enzyme in the catabolism of the pyrimidine bases uracil, thymine and the antineoplastic agent 5-fluorouracil. Genetic variations in the gene encoding DPD (DPYD) have emerged as predictive risk alleles for 5FU-associated toxicity. Here we report an in-depth analysis of genetic variants in DPYD and their consequences for DPD activity and pyrimidine metabolites in 100 Dutch healthy volunteers. 34 SNPs were detected in DPYD and 15 SNPs were associated with altered plasma concentrations of pyrimidine metabolites. DPD activity was significantly associated with the plasma concentrations of uracil, the presence of a specific DPYD mutation (c.1905+1G>A) and the combined presence of three risk variants in DPYD (c.1905+1G>A, c.1129-5923C>G, c.2846A>T), but not with an altered uracil/dihydrouracil (U/UH2) ratio. Various haplotypes were associated with different DPD activities (haplotype D3, a decreased DPD activity; haplotype F2, an increased DPD activity). Functional analysis of eight recombinant mutant DPD enzymes showed a reduced DPD activity, ranging from 35% to 84% of the wild-type enzyme. Analysis of a DPD homology model indicated that the structural effect of the novel p.G401R mutation is most likely minor. The clinical relevance of the p.D949V mutation was demonstrated in a cancer patient heterozygous for the c.2846A>T mutation and a novel nonsense mutation c.1681C>T (p.R561X), experiencing severe grade IV toxicity. Our studies showed that the endogenous levels of uracil and the U/UH2 ratio are poor predictors of an impaired DPD activity. Loading studies with uracil to identify patients with a DPD deficiency warrants further investigation.

  17. Cytotoxic activity of a synthetic deoxypodophyllotoxin derivative with an opened D-ring.

    PubMed

    Chen, Chuan; Wang, Cui-Cui; Wang, Zhong; Geng, Wen-Yue; Xu, Hui; Song, Xiao-Mei; Luo, Du-Qiang

    2016-05-01

    Podophyllotoxin and its synthetic derivatives are valuable medicinal agents that have antitumor, insecticidal, and antifungal properties. We previously synthesized a deoxypodophyllotoxin derivative with an opened D-ring (DPD) exhibiting potent insecticidal activity. This article was firstly performed to identify the cytotoxicity of DPD toward human cancer cell lines (SGC7901, HeLa, and A549) and normal cell line (HEK293T) using MTT assay. DPD showed potent cytotoxicity against human cancer lines (HeLa and A549) and less cytotoxicity against normal cell lines HEK293T. DPD could also induce the cell cycle arrest at G2/M phase in HeLa cells and significantly increase the phosphorylation (Tyr 15) of CDC2 leading to inactivation of CDC2. The effects of DPD on cellular microtubule networks were detected using immunofluorescence technique in HeLa cells. The immunofluorescence results showed DPD influenced the arrangement and organization of cellular microtubule networks in HeLa cells. Microtubules are long, hollow cylinders made up of polymerized tubulin dimers. Total microtubules were separated after DPD treatment. Western blot results showed that the free polymerized tubulin dimers were obviously increased after DPD treatment. DPD may be a good drug candidate with the therapeutic potential to human cancer by affecting microtubule polymerization.

  18. Polarizable water model for Dissipative Particle Dynamics

    NASA Astrophysics Data System (ADS)

    Pivkin, Igor; Peter, Emanuel

    2015-11-01

    Dissipative Particle Dynamics (DPD) is an efficient particle-based method for modeling mesoscopic behavior of fluid systems. DPD forces conserve the momentum resulting in a correct description of hydrodynamic interactions. Polarizability has been introduced into some coarse-grained particle-based simulation methods; however it has not been done with DPD before. We developed a new polarizable coarse-grained water model for DPD, which employs long-range electrostatics and Drude oscillators. In this talk, we will present the model and its applications in simulations of membrane systems, where polarization effects play an essential role.

  19. Depersonalization Disorder: Disconnection of Cognitive Evaluation from Autonomic Responses to Emotional Stimuli

    PubMed Central

    Michal, Matthias; Koechel, Ansgar; Canterino, Marco; Adler, Julia; Reiner, Iris; Vossel, Gerhard; Beutel, Manfred E.; Gamer, Matthias

    2013-01-01

    Background Patients with depersonalization disorder (DPD) typically complain about emotional detachment. Previous studies found reduced autonomic responsiveness to emotional stimuli for DPD patients as compared to patients with anxiety disorders. We aimed to investigate autonomic responsiveness to emotional auditory stimuli of DPD patients as compared to patient controls. Furthermore, we examined the modulatory effect of mindful breathing on these responses as well as on depersonalization intensity. Methods 22 DPD patients and 15 patient controls balanced for severity of depression and anxiety, age, sex and education, were compared regarding 1) electrodermal and heart rate data during a resting period, and 2) autonomic responses and cognitive appraisal of standardized acoustic affective stimuli in two conditions (normal listening and mindful breathing). Results DPD patients rated the emotional sounds as significantly more neutral as compared to patient controls and standardized norm ratings. At the same time, however, they responded more strongly to acoustic emotional stimuli and their electrodermal response pattern was more modulated by valence and arousal as compared to patient controls. Mindful breathing reduced severity of depersonalization in DPD patients and increased the arousal modulation of electrodermal responses in the whole sample. Finally, DPD patients showed an increased electrodermal lability in the rest period as compared to patient controls. Conclusions These findings demonstrated that the cognitive evaluation of emotional sounds in DPD patients is disconnected from their autonomic responses to those emotional stimuli. The increased electrodermal lability in DPD may reflect increased introversion and cognitive control of emotional impulses. The findings have important psychotherapeutic implications. PMID:24058547

  20. Depersonalization disorder: disconnection of cognitive evaluation from autonomic responses to emotional stimuli.

    PubMed

    Michal, Matthias; Koechel, Ansgar; Canterino, Marco; Adler, Julia; Reiner, Iris; Vossel, Gerhard; Beutel, Manfred E; Gamer, Matthias

    2013-01-01

    Patients with depersonalization disorder (DPD) typically complain about emotional detachment. Previous studies found reduced autonomic responsiveness to emotional stimuli for DPD patients as compared to patients with anxiety disorders. We aimed to investigate autonomic responsiveness to emotional auditory stimuli of DPD patients as compared to patient controls. Furthermore, we examined the modulatory effect of mindful breathing on these responses as well as on depersonalization intensity. 22 DPD patients and 15 patient controls balanced for severity of depression and anxiety, age, sex and education, were compared regarding 1) electrodermal and heart rate data during a resting period, and 2) autonomic responses and cognitive appraisal of standardized acoustic affective stimuli in two conditions (normal listening and mindful breathing). DPD patients rated the emotional sounds as significantly more neutral as compared to patient controls and standardized norm ratings. At the same time, however, they responded more strongly to acoustic emotional stimuli and their electrodermal response pattern was more modulated by valence and arousal as compared to patient controls. Mindful breathing reduced severity of depersonalization in DPD patients and increased the arousal modulation of electrodermal responses in the whole sample. Finally, DPD patients showed an increased electrodermal lability in the rest period as compared to patient controls. These findings demonstrated that the cognitive evaluation of emotional sounds in DPD patients is disconnected from their autonomic responses to those emotional stimuli. The increased electrodermal lability in DPD may reflect increased introversion and cognitive control of emotional impulses. The findings have important psychotherapeutic implications.

  1. Functional study of dextran-graft-poly((2-dimethyl amino)ethyl methacrylate) gene delivery vector for tumor therapy.

    PubMed

    Li, Wen-Bin; Yuan, Wei; Xu, Fu-Jian; Zhao, Chen; Ma, Jie; Zhan, Qi-Min

    2013-07-01

    The obstacle of gene therapy is the shortage of efficient delivery system. The development of the gene delivery system with high transfection efficiency and low toxicity appears to be crucial. Recently, we reported that the dextran-graft-poly((2-dimethyl amino)ethyl methacrylate) (DPD) can be potentially used as efficient gene vector. Herein, DPD was systematically studied for its potential in tumor gene therapy. DPD was synthesized and characterized by agarose gel electrophoresis, particle size and zeta potential. The particle size and zeta potential of the DPD/enhanced green fluorescent protein (pEGFP-C1) plasmid complexes at various N/P ratios were 130-150 nm and about 40 mV, respectively. The results showed that DPD exhibit a higher transfection effect compared with Lipofectamine 2K (Lipo 2K), a commercialized vector. The possibility of DPD in gene therapy was evaluated using p53, a gene that has been wildly applied in the research of cancer gene therapy. DPD/pEGFP-C1-p53 complex was found to be able to inhibit tumor cell proliferation through cell cycle arrest and apoptosis. Moreover, the tumor growth was found to be restrained when DPD/pEGFP-C1-p53 complex was used in a xenograft MCF7 tumor model in vivo. These observations indicated that DPD/pEGFP-C1-p53 complex may be considered to be an efficient delivery system for tumor gene therapy.

  2. 1,6-Bis[4-(4-amino-3-hydroxyphenoxy)phenyl] diamantane potentiates in vitro and in vivo antitumor effects of irinotecan on human colorectal cancer cells.

    PubMed

    Yang, Po-Sheng; Wang, Jane-Jen; Wang, Yea-Hwey; Jan, Woan-Ching; Cheng, Shih-Ping; Hsu, Yi-Chiung

    2016-05-01

    1,6-Bis[4-(4-amino-3-hydroxyphenoxy)phenyl] diamantane (DPD), a diamantane derivative, was previously noted as an anticancer compound through anticancer drug screening with NCI-60 human tumor cells. Irinotecan (CPT-11), a semisynthetic derivative of camptothecin, is clinically active in the treatment of colorectal cancer, with no cross-resistance. The current study conducted a pharmacokinetic evaluation of DPD, an essential component of drug discovery. Subsequent pathway analysis of microarray gene expression data indicated that the anticancer mechanisms of DPD were associated with cell cycle progression and apoptosis. The combined effect of DPD and CPT-11 with regard to the mechanisms of apoptosis-related pathways in COLO 205 cells, and the antitumor effects in colon cancer xenograft mice, were investigated. The plasma concentration and pharmacokinetic parameters of DPD in male albino rats were analyzed following a single dose of DPD by injection. The protein expression of active caspase-3, procaspase-3 and poly ADP-ribose polymerase (PARP) in COLO 205 cells treated with DPD and CPT-11, alone or combined, was evaluated by western blotting. A trypan blue dye exclusion assay revealed that, whilst DPD alone demonstrated good antitumor effects, this effect was potentiated when combined with CPT-11. Combined treatment with DPD and CPT-11 upregulated the expression of cleaved PARP, procaspase-3, caspase-3 and active caspase-3 in COLO 205 cells. In the colon cancer xenograft model, compared with the control (vehicle-treated) mice, the sizes of the tumors were significantly lower in mice treated with DPD and CPT-11, alone or in combination. Thus, DPD may be a potential therapeutic agent for the treatment of colorectal cancer via upregulating apoptosis-related pathways.

  3. Spatial analysis of drug poisoning deaths in the American West, particularly Utah.

    PubMed

    Kerry, Ruth; Goovaerts, Pierre; Vowles, Maureen; Ingram, Ben

    2016-07-01

    Most states in the Western US have high rates of drug poisoning death (DPD), especially New Mexico, Nevada, Arizona and Utah (UT). This seems paradoxical in UT where illicit drug use, smoking and drinking rates are low. To investigate this, spatial analysis of county level DPD data and other relevant factors in the Western US and UT was undertaken. Poisson kriging was used to smooth the DPD data, populate data gaps and improve the reliability of rates recorded in sparsely populated counties. Links between DPD and economic, environmental, health, lifestyle, and demographic factors were investigated at four scales using multiple linear regression. LDS church membership and altitude, factors not previously considered, were included. Spatial change in the strength and sign of relationships was investigated using geographically weighted regression and significant DPD clusters were identified using the Local Moran's I. Economic factors, like the sharp social gradient between rural and urban areas were important to DPD throughout the west. Higher DPD rates were also found in areas of higher elevation and the desert rural areas in the south. The unique characteristics of DPD in UT in terms of health and lifestyle factors, as well as the demographic structure of DPD in the most LDS populous states (UT, Idaho, Wyoming), suggest that high DPD in heavily LDS areas are predominantly prescription opioid related whereas in other Western states a larger proportion of DPD might come from illicit drugs. Drug policies need to be adapted to the geographical differences in the dominant type of drug causing death. Educational materials need to be marketed to the demographic groups at greatest risk and take into account differences in population characteristics between and within States. Some suggestions about how such adaptations can be made are given and future research needs outlined. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Regulation of dihydropyrimidine dehydrogenase in colorectal cancer.

    PubMed

    Johnston, S J; Ridge, S A; Cassidy, J; McLeod, H L

    1999-09-01

    Dihydropyrimidine dehydrogenase (DPD) is responsible for degradation of the pyrimidines uracil and thymine and the inactivation of the chemotherapeutic agent 5-fluorouracil. DPD activity is highly variable in cancer populations, and this variation may influence the antitumor efficacy of 5-fluorouracil. However, little is known about the regulation of DPD mRNA expression in any tissues. Using a reverse transcription competitive PCR assay, we quantified DPD mRNA levels in 10 matched colorectal tumors and adjacent normal mucosae and 7 colorectal liver metastases and adjacent normal livers. Lower levels of DPD mRNA expression were observed in colorectal tumor compared with adjacent normal colon mucosa (median, 0.01 versus 0.37 amole/microg total RNA, P = 0.02). DPD mRNA expression was also lower in metastases than adjacent normal liver tissue (median, 0.11 versus 1.17 amole/microg total RNA, P = 0.001). DPD mRNA expression was higher in normal liver than normal colonic mucosa (median, 1.17 versus 0.37 amole/microg total RNA, P = 0.02). A significant relationship was observed between DPD mRNA and catalytic activity (r(s) = 0.66, P<0.001). The tumor:normal ratio for DPD mRNA, protein, and activity was relatively stable in liver (0.25, 0.55, and 0.51, respectively) but varied considerably in colon (0.085, 0.9, and 1.25, respectively), consistent with enhanced translation of DPD transcript in primary colorectal tumor. This suggests that DPD can be regulated at the levels of both transcription and translation.

  5. 1,6-Bis[4-(4-amino-3-hydroxyphenoxy)phenyl] diamantane potentiates in vitro and in vivo antitumor effects of irinotecan on human colorectal cancer cells

    PubMed Central

    YANG, PO-SHENG; WANG, JANE-JEN; WANG, YEA-HWEY; JAN, WOAN-CHING; CHENG, SHIH-PING; HSU, YI-CHIUNG

    2016-01-01

    1,6-Bis[4-(4-amino-3-hydroxyphenoxy)phenyl] diamantane (DPD), a diamantane derivative, was previously noted as an anticancer compound through anticancer drug screening with NCI-60 human tumor cells. Irinotecan (CPT-11), a semisynthetic derivative of camptothecin, is clinically active in the treatment of colorectal cancer, with no cross-resistance. The current study conducted a pharmacokinetic evaluation of DPD, an essential component of drug discovery. Subsequent pathway analysis of microarray gene expression data indicated that the anticancer mechanisms of DPD were associated with cell cycle progression and apoptosis. The combined effect of DPD and CPT-11 with regard to the mechanisms of apoptosis-related pathways in COLO 205 cells, and the antitumor effects in colon cancer xenograft mice, were investigated. The plasma concentration and pharmacokinetic parameters of DPD in male albino rats were analyzed following a single dose of DPD by injection. The protein expression of active caspase-3, procaspase-3 and poly ADP-ribose polymerase (PARP) in COLO 205 cells treated with DPD and CPT-11, alone or combined, was evaluated by western blotting. A trypan blue dye exclusion assay revealed that, whilst DPD alone demonstrated good antitumor effects, this effect was potentiated when combined with CPT-11. Combined treatment with DPD and CPT-11 upregulated the expression of cleaved PARP, procaspase-3, caspase-3 and active caspase-3 in COLO 205 cells. In the colon cancer xenograft model, compared with the control (vehicle-treated) mice, the sizes of the tumors were significantly lower in mice treated with DPD and CPT-11, alone or in combination. Thus, DPD may be a potential therapeutic agent for the treatment of colorectal cancer via upregulating apoptosis-related pathways. PMID:27123150

  6. Spatial Analysis of Drug Poisoning Deaths in the American West, particularly Utah

    PubMed Central

    Kerry, Ruth; Goovaerts, Pierre; Vowles, Maureen; Ingram, Ben

    2016-01-01

    Background Most states in the Western US have high rates of drug poisoning death (DPD), especially New Mexico, Nevada, Arizona and Utah (UT). This seems paradoxical in UT where illicit drug use, smoking and drinking rates are low. To investigate this, spatial analysis of county level DPD data and other relevant factors in the Western US and UT was undertaken. Methods Poisson kriging was used to smooth the DPD data, populate data gaps and improve the reliability of rates recorded in sparsely populated counties. Links between DPD and economic, environmental, health, lifestyle, and demographic factors were investigated at four scales using multiple linear regression. LDS church membership and altitude, factors not previously considered, were included. Spatial change in the strength and sign of relationships was investigated using geographically weighted regression and significant DPD clusters were identified using the Local Moran’s I. Results Economic factors, like the sharp social gradient between rural and urban areas were important to DPD throughout the west. Higher DPD rates were also found in areas of higher elevation and the desert rural areas in the south. The unique characteristics of DPD in UT in terms of health and lifestyle factors, as well as the demographic structure of DPD in the most LDS populous states (UT, Idaho, Wyoming), suggest that high DPD in heavily LDS areas are predominantly prescription opioid related whereas in other Western states a larger proportion of DPD might come from illicit drugs. Conclusions Drug policies need to be adapted to the geographical differences in the dominant type of drug causing death. Educational materials need to be marketed to the demographic groups at greatest risk and take into account differences in population characteristics between and within States. Some suggestions about how such adaptations can be made are given and future research needs outlined. PMID:27286759

  7. Educacion en Poblaciones Indigenas: Politicas y Estrategias en America Latina. (Education for Indigenous Populations: Policies and Strategies in Latin America).

    ERIC Educational Resources Information Center

    Zuniga, Madeleine, Ed.; And Others

    This document is a compilation of 20 papers from a seminar on educational policy and strategy for educating the indigenous peoples of Latin America and Mexico. There is a growing awareness among linguistics and anthropology specialists and educators of the necessity to validate education that respects the values of an indigenous culture. This…

  8. Steps toward Unifying Dual Language Programs, Common Core State Standards, and Critical Pedagogy: Oportunidades, Estrategias Y Retos

    ERIC Educational Resources Information Center

    Alfaro, Cristina; Durán, Richard; Hunt, Alexandra; Aragón, María José

    2014-01-01

    Recent education reforms have begun to reframe academic discussion and teacher practice surrounding bilingual educational approaches for preparing "21st century, college and career ready" citizens. Given this broader context, in this article we examine ways that we might join implementation of dual language programs, Common Core State…

  9. Educacion en Poblaciones Indigenas: Politicas y Estrategias en America Latina. (Education for Indigenous Populations: Policies and Strategies in Latin America).

    ERIC Educational Resources Information Center

    Zuniga, Madeleine, Ed.; And Others

    This document is a compilation of 20 papers from a seminar on educational policy and strategy for educating the indigenous peoples of Latin America and Mexico. There is a growing awareness among linguistics and anthropology specialists and educators of the necessity to validate education that respects the values of an indigenous culture. This…

  10. Estrategias para mejorar los resultados academicos para las latinas (Strategies for Improving the Educational Outcomes of Latinas). ERIC Digest.

    ERIC Educational Resources Information Center

    Schwartz, Wendy

    The educational experiences of Latinas are affected by the interaction of many factors, including poverty, racism, sexual harassment, and lack of English language proficiency. This Spanish-language digest presents a range of strategies that schools can employ to promote the academic achievement of Latinas. Schools should communicate that Hispanic…

  11. Steps toward Unifying Dual Language Programs, Common Core State Standards, and Critical Pedagogy: Oportunidades, Estrategias Y Retos

    ERIC Educational Resources Information Center

    Alfaro, Cristina; Durán, Richard; Hunt, Alexandra; Aragón, María José

    2014-01-01

    Recent education reforms have begun to reframe academic discussion and teacher practice surrounding bilingual educational approaches for preparing "21st century, college and career ready" citizens. Given this broader context, in this article we examine ways that we might join implementation of dual language programs, Common Core State…

  12. [Tumoral dihydropyrimidine dehydrogenase expression and efficacy of 5-fluorouracil plus leucovorin plus UFT therapy in patients with colorectal cancer].

    PubMed

    Ishida, Hideyuki; Ohsawa, Tomonori; Nakada, Hiroshi; Yokoyama, Masaru; Inokuma, Shigehisa; Shirakawa, Kazuo; Yamada, Hirofumi; Hashimoto, Daijo

    2004-06-01

    The purpose of this study was to examine the relation between tumoral expression of dihydropyrimidine dehydrogenase (DPD), the rate limiting enzyme of the degradation pathway 5-fluorouracil (5-FU), and the efficacy of 5-FU based chemotherapy for colorectal cancer. Twenty-eight colorectal cancer patients who had underwent noncurative resection (n = 16) or had developed recurrence (n = 12) were enrolled. All patients were given 5-FU plus leucovorin intravenously and UFT (1 M Tegafur, 4 M Uracil) perorally. The expression levels of the DPD in the primary lesions were determined by the enzyme-linked immunosorbent assay. Group A (n = 10) consisted of one patient with complete response, 4 with partial response, and 5 with no change (time to disease progression (TTP) > = 90 days). Group B (n = 18) consisted of 14 patients with progressive disease and 4 with NC (time to progression, < 90 days). The tumoral DPD levels did not differ between the groups (p = 0.58). There were no effective cases (n = 6) whose tumoral DPD levels were equal to or more than 83.2 U/mg protein (high DPD expression). There were marked overlaps in the DPD levels between the two groups whose DPD levels were less than 83.0 U/mg protein (moderate or low expression). These results suggest that high expression of tumoral DPD would be predictive to failure of fluoropyrimidine-based treatment. However, it is unlikely to set the optimal cutoff value for predicting the efficacy of this type of chemotherapy.

  13. Application of the dissipative particle dynamics method to the instability problem of a liquid thread

    NASA Astrophysics Data System (ADS)

    Mo, Chao-jie; Qin, Li-zi; Zhao, Fei; Yang, Li-jun

    2016-12-01

    We investigate the application of the dissipative particle dynamics method to the instability problem of a long liquid thread surrounded by another fluid. The dispersion curves obtained from simulations are compared with classic theoretical predictions. The results from standard dissipative particle dynamics (DPD) simulations at first have a tendency of gradually approaching to Tomotika's Stokes flow prediction when the Reynolds number is decreased. But they then abnormally deviate again when the viscosity is very large. The same phenomenon is also confirmed in droplet retraction simulations when also compared with theoretical Stokes flow results. On the other hand, when a hard-core DPD model is used, with the decrease of the Reynolds number the simulation results did finally approach Tomotika's predictions when Re ≈0.1 . A combined presentation of the hard-core DPD results and the standard DPD results, excluding the abnormal ones, demonstrates that they are approximately on a continuum when labeled with Reynolds number. These results suggest that the standard DPD method is a suitable method for investigation of the instability problem of immersed liquid thread in the inertioviscous regime (0.1 DPD fluid, while the hard-core DPD is suitable to overcome this inferiority with standard DPD.

  14. Biological Evaluation of Methods for the Determination of Free Available Chlorine.

    DTIC Science & Technology

    1980-03-01

    methods tested yielded false positive determinations of free chlorine with one or more of the inorganic chloramines . The FACTS procedure was the most...13 Chloramine preparation ............................... 13 Colorimetric tests ................................... 16 Chlorine membrane electrode...50 Biofac ............................................... . 50 Chloramines .......................................... 54 DPD and DPD

  15. Fokker-Planck-Boltzmann equation for dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Marsh, C. A.; Backx, G.; Ernst, M. H.

    1997-05-01

    The algorithm for Dissipative Particle Dynamics (DPD), as modified by Español and Warren, is used as a starting point for proving an H-theorem for the free energy and deriving hydrodynamic equations. Equilibrium and transport properties of the DPD fluid are explicitly calculated in terms of the system parameters for the continuous time version of the model.

  16. Using the Principles of Differentiated Instruction to Improve Professional Development

    ERIC Educational Resources Information Center

    Lentz, Daniel E.

    2014-01-01

    The purpose of this study was to create a model of Differentiated Professional Development (DPD) that is a more effective method of professional development due to the addition of the principles of differentiated instruction (DI). The DPD model was created by combining previous studies on effective elements of professional development with the…

  17. Attributions, appraisals and attention for symptoms in depersonalisation disorder.

    PubMed

    Hunter, Elaine C M; Salkovskis, Paul M; David, Anthony S

    2014-02-01

    A cognitive-behavioural model of depersonalisation disorder (DPD) suggests that catastrophic attributions and appraisals, and increased attention to symptoms, play important roles in the development and maintenance of the disorder. Empirical testing of this model was investigated in three groups: 25 patients with DPD, 21 patients with anxiety (obsessive-compulsive or panic disorder), and 22 psychiatrically healthy participants. Task 1 examined attributions for ambiguous symptoms. Task 2 used a questionnaire to compare the groups on the content, frequency, and conviction in appraisals when participants worried about their health. Task 3 employed four experimental manipulations designed to either increase, or decrease, attention to catastrophic appraisals and/or symptoms of DPD. Results indicate that the DPD group make less normalising attributions for symptoms (Task 1) and have more catastrophic appraisals (Task 2) than those in the Healthy Control group. The DPD and Anxiety groups were similar in their patterns of appraisals and attributions. In Task 3, the DPD group showed a perceived reduction in DPD severity when their attention was focussed on cognitively demanding tasks, whereas the other two groups showed an increase. The findings are consistent with the hypothesis that these cognitive processes play an important role in the development and maintenance of DPD.

  18. Application of the dissipative particle dynamics method to the instability problem of a liquid thread.

    PubMed

    Mo, Chao-Jie; Qin, Li-Zi; Zhao, Fei; Yang, Li-Jun

    2016-12-01

    We investigate the application of the dissipative particle dynamics method to the instability problem of a long liquid thread surrounded by another fluid. The dispersion curves obtained from simulations are compared with classic theoretical predictions. The results from standard dissipative particle dynamics (DPD) simulations at first have a tendency of gradually approaching to Tomotika's Stokes flow prediction when the Reynolds number is decreased. But they then abnormally deviate again when the viscosity is very large. The same phenomenon is also confirmed in droplet retraction simulations when also compared with theoretical Stokes flow results. On the other hand, when a hard-core DPD model is used, with the decrease of the Reynolds number the simulation results did finally approach Tomotika's predictions when Re≈0.1. A combined presentation of the hard-core DPD results and the standard DPD results, excluding the abnormal ones, demonstrates that they are approximately on a continuum when labeled with Reynolds number. These results suggest that the standard DPD method is a suitable method for investigation of the instability problem of immersed liquid thread in the inertioviscous regime (0.1DPD fluid, while the hard-core DPD is suitable to overcome this inferiority with standard DPD.

  19. Assessment of mesoscopic particle-based methods in microfluidic geometries

    NASA Astrophysics Data System (ADS)

    Zhao, Tongyang; Wang, Xiaogong; Jiang, Lei; Larson, Ronald G.

    2013-08-01

    We assess the accuracy and efficiency of two particle-based mesoscopic simulation methods, namely, Dissipative Particle Dynamics (DPD) and Stochastic Rotation Dynamics (SRD) for predicting a complex flow in a microfluidic geometry. Since both DPD and SRD use soft or weakly interacting particles to carry momentum, both methods contain unavoidable inertial effects and unphysically high fluid compressibility. To assess these effects, we compare the predictions of DPD and SRD for both an exact Stokes-flow solution and nearly exact solutions at finite Reynolds numbers from the finite element method for flow in a straight channel with periodic slip boundary conditions. This flow represents a periodic electro-osmotic flow, which is a complex flow with an analytical solution for zero Reynolds number. We find that SRD is roughly ten-fold faster than DPD in predicting the flow field, with better accuracy at low Reynolds numbers. However, SRD has more severe problems with compressibility effects than does DPD, which limits the Reynolds numbers attainable in SRD to around 25-50, while DPD can achieve Re higher than this before compressibility effects become too large. However, since the SRD method runs much faster than DPD does, we can afford to enlarge the number of grid cells in SRD to reduce the fluid compressibility at high Reynolds number. Our simulations provide a method to estimate the range of conditions for which SRD or DPD is preferable for mesoscopic simulations.

  20. Evaluation of clinical value of single nucleotide polymorphisms of dihydropyrimidine dehydrogenase gene to predict 5-fluorouracil toxicity in 60 colorectal cancer patients in China.

    PubMed

    Zhang, Xin; Sun, Butong; Lu, Zhenxia

    2013-01-01

    Dihydropyrimidine dehydrogenase (DPD) activity could be affected by single nucleotide polymorphisms (SNPs), resulting in either no effect, partial or complete loss of DPD activity. To evaluate if SNPs of DPD can be used to predict 5-FU toxicity, we evaluated five SNPs of DPD (14G1A, G1156T, G2194A, T85C and T464A) by TaqMan real time PCR in 60 colorectal cancer patients. Clinical data demonstrated that there was higher correlation between DPD activity and toxic effects of 5-FU (p<0.05). Six patients were positive for G2194A detection, which were all heterozygous. Two patients had lower DPD activities (< 3) with higher toxic effects (≥ stage III) while one patient was also positive for T85C detection. Ten patients were positive for T85C detection. Two patients were homozygous with lower DPD activities and higher toxic effects. Two patients were positive for the T464A detection, which were heterozygous with lower DPD activity and higher toxic effects and also positive for T85C detection. These data clearly indicated that the T464A and homozygous of the T85C are stronger biomarkers to predict the 5-FU toxicity. Our study significantly indicated that the detection for G2194A, T85C and T464A could predict ~13% of 5-FU severe toxic side effects.

  1. Diseno de una Actividad de Aprendizaje Basada en la Argumentacion Dialogica en un curso Virtual de Biotecnologia y su Incidencia en el Desarrollo de Competencias Cientificas

    NASA Astrophysics Data System (ADS)

    Ortiz Benavides, Fedra Lorena

    El proposito de la investigacion fue evaluar la efectividad de una actividad de aprendizaje basado en la argumentacion dialogica en linea y su incidencia en el desarrollo de competencias cientificas. Se fundamenta en la teoria del aprendizaje socio cultural de Vigotsky (1984), los principios del diseno instruccional de la cognicion situada por Hung y Der-Thang (2001) y como estrategia se aplico la argumentacion dialogica utilizando el Modelo Argumentativo de Toulmin MAT (1984). El diseno experimental comparo dos grupos de estudiantes A y B en el curso virtual de Biotecnologia. El grupo A (experimental) desarrollo la discusion a partir de la estrategia disenada para este estudio y el grupo B (control) realizo la discusion desde las actividades tradicionales. El desarrollo de la competencia argumentativa se valoro con el instrumento de evaluacion para argumentacion dialogica en linea propuesta por Clark y Sampson (2008). La evaluacion de las competencias cientificas se realizo a partir de una postprueba. Los datos fueron analizados con pruebas estadisticas no parametricas. Los resultados de la investigacion, indicaron diferencias significativas en el nivel de la competencia argumental en el grupo experimental en comparacion al grupo control. Igualmente se demostro que existe una relacion positiva entre el nivel de desarrollo de la competencia argumentativa y el nivel de desarrollo de las competencias cientificas.

  2. Modeling wrinkled-assisted assembly of ordered nanoparticles and nanorods on a wavy substrate

    NASA Astrophysics Data System (ADS)

    Luppi Sato, Camila; Yeh, Peter; Alexeev, Alexander; Mayer, Martin; Probst, Patrick; Fery, Andreas

    2015-11-01

    Wrinkle-assisted assembly is a technique that allows for fabrication of ordered structures of nanoparticles and nanorods on hydrophilic substrates. As an intermediate step in this process, nanoparticles are deposited within microscopically wrinkled surfaces, where they organize into patterned structures upon solvent evaporation. However, the dependence of the resulting pattern on nanoparticle concentration, particle size and shape, and substrate geometry is not well understood. We develop a model of the ordering process using dissipative particle dynamics (DPD) to predict the resulting nanostructures. We approximate the wavy sheet as a sinusoidal surface. One layer of DPD liquid containing nanoparticles fills the surface, while another layer of DPD fluid acts as the gaseous phase. We model the evaporative process by gradually replacing DPD liquid particles with DPD gaseous particles. The results of our work are useful in designing surface patterns that exhibit strong plasmonic coupling. Financial support from NSF CAREER Award DMR-1255288 is gratefully acknowledged.

  3. [Education for patients with fibromyalgia. A systematic review of randomised clinical trials].

    PubMed

    Elizagaray-Garcia, Ignacio; Muriente-Gonzalez, Jorge; Gil-Martinez, Alfonso

    2016-01-16

    Objetivo. Analizar la efectividad de la educacion al paciente con fibromialgia sobre el dolor, calidad de vida y funcionalidad. Sujetos y metodos. La busqueda de articulos se realizo utilizando bases de datos electronicas. Los criterios de inclusion fueron: estudios clinicos aleatorizados y controlados (ECA), realizados en pacientes con fibromialgia, donde la intervencion terapeutica se basara en la educacion al paciente, y publicados en ingles y castellano. Dos revisores independientes analizaron la calidad metodologica utilizando la escala PEDro. Resultados. Se seleccionaron cinco ECA, de los cuales cuatro presentaron una calidad metodologica buena. En tres de los estudios, la educacion al paciente, en combinacion con otra intervencion basada en ejercicio terapeutico, mejoro los resultados en las variables que evaluaron el dolor y la calidad de vida en comparacion con las mismas intervenciones realizadas por separado. Ademas, un ECA de buena calidad metodologica mostro que la educacion al paciente activo vias neurales inhibitorias descendentes del dolor. El analisis cualitativo muestra evidencia fuerte-moderada acerca de que la educacion al paciente, en combinacion con otras intervenciones de ejercicio terapeutico, ofrece resultados positivos en las variables de dolor, calidad de vida y funcionalidad. Conclusiones. La educacion al paciente por si sola no ha mostrado ser efectiva sobre el dolor, la calidad de vida ni la funcionalidad en pacientes con fibromialgia. Existe evidencia fuerte de la efectividad de la combinacion de educacion al paciente con ejercicio y estrategias activas de afrontamiento sobre el dolor, la calidad de vida y la funcionalidad a corto, medio y largo plazo en pacientes con fibromialgia.

  4. Immunohistochemical demonstration of fluoropyrimidine-metabolizing enzymes in various types of cancer.

    PubMed

    Kamoshida, Shingo; Shiogama, Kazuya; Shimomura, Ryoichi; Inada, Ken-Ichi; Sakurai, Yoichi; Ochiai, Masahiro; Matuoka, Hiroshi; Maeda, Kotaro; Tsutsumi, Yutaka

    2005-11-01

    Fluoropyrimidines [5-Fluorouracil (5-FU) and its prodrugs] have been widely used in the treatment of solid cancers. The anticancer effects primarily depend on intratumoral levels of enzymes metabolizing the drugs, such as dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyltransferase (OPRT), thymidine phosphorylase (TP), and thymidylate synthase (TS). In order to know the tumor types susceptible to respective fluoropyrimidines, we investigated the expression of DPD, OPRT, TP and TS in various types of cancer with the immunoperoxidase method. These four enzymes existed in all of the cancer types studied, such as pulmonary, gastric, colorectal, hepatic, cholecystic, pancreatic, renal, urocystic, and mammary cancers. Respective types of cancers presented characteristic immunohistochemical features as follows: pulmonary adenocarcinoma, DPD- and TP-high; pulmonary squamous cell carcinoma, TS- and TP-high; intestinal-type gastric adenocarcinoma, TP-high; diffuse-type gastric adenocarcinoma, DPD-low and TS-high; colorectal adenocarcinoma, DPD- and TP-low, hepatocellular carcinoma, DPD-high, and TS- and OPRT-low; cholecystic adenocarcinoma, DPD- and TS-high; renal cell carcinoma, DPD-low, and OPRT- and TP-high; urocystic transitional cell carcinoma, DPD-high and OPRT-low; and mammary ductal carcinoma, OPRT-low, and TS- and TP-high. The enzyme expression pattern in cancer tissue was generally similar to that of their normal counterparts. However, TP immunoreactivity in adenocarcinomas of the lung, stomach and gallbladder, and urothelial carcinoma of the urinary bladder was stronger, and DPD immunoreactivity in adenocarcinoma of the breast was weaker, when compared with normal epithelial cells. Non-epithelial cells were also positive for these enzymes. These results indicated that the key enzymes influencing the effects of fluoropyrimidines differ from cancer to cancer. Fluoropyrimidine treatment may be selected, based on the simultaneous immunohistochemical

  5. Impact of intratumoral expression levels of fluoropyrimidine-metabolizing enzymes on treatment outcomes of adjuvant S-1 therapy in gastric cancer.

    PubMed

    Kim, Ji-Yeon; Shin, Eun; Kim, Jin Won; Lee, Hye Seung; Lee, Dae-Won; Kim, Se-Hyun; Lee, Jeong-Ok; Kim, Yu Jung; Kim, Jee Hyun; Bang, Soo-Mee; Ahn, Sang-Hoon; Park, Do Joong; Lee, Jong Seok; Lee, Ju-Seog; Kim, Hyung-Ho; Lee, Keun-Wook

    2015-01-01

    We analyzed the expression levels of fluoropyrimidine-metabolizing enzymes (thymidylate synthase [TS], dihydropyrimidine dehydrogenase [DPD], thymidine phosphorylase [TP] and orotate phosphoribosyltransferase [OPRT]) to identify potential biomarkers related to treatment outcomes in gastric cancer (GC) patients receiving adjuvant S-1 chemotherapy. In this study, 184 patients who received curative gastrectomy (D2 lymph node dissection) and adjuvant S-1 were included. Immunohistochemistry and quantitative reverse transcription polymerase chain reaction were performed to measure the protein and mRNA levels of TS, DPD, TP, and OPRT in tumor tissue. In univariate analysis, low intratumoral DPD protein expression was related to poorer 5-year disease-free survival (DFS; 78% vs. 88%; P = 0.068). Low intratumoral DPD mRNA expression (1st [lowest] quartile) was also related to poorer DFS (69% vs. 90%; P < 0.001) compared to high intratumoral DPD expression (2nd to 4th quartiles). In multivariate analyses, low intratumoral DPD protein or mRNA expression was related to worse DFS (P < 0.05), irrespective of other clinical variables. TS, TP, and OPRT expression levels were not related to treatment outcomes. Severe non-hematologic toxicities (grade ≥ 3) had a trend towards more frequent development in patients with low intratumoral DPD mRNA expression (29% vs. 16%; P = 0.068). In conclusion, GC patients with high intratumoral DPD expression did not have inferior outcome following adjuvant S-1 therapy compared with those with low DPD expression. Instead, low intratumoral DPD expression was related to poor DFS.

  6. Utero-placental vascularisation in normal and preeclamptic and intra-uterine growth restriction pregnancies: third trimester quantification using 3D power Doppler with comparison to placental vascular morphology (EVUPA): a prospective controlled study

    PubMed Central

    Duan, Jie; Chabot-Lecoanet, Anne-Claire; Perdriolle-Galet, Estelle; Christov, Christophe; Hossu, Gabriela; Cherifi, Aboubaker; Morel, Olivier

    2016-01-01

    Introduction Preeclampsia (PE) and intra-uterine growth restriction (IUGR) are two major pregnancy complications related to chronic utero-placental hypoperfusion. Three-dimensional power Doppler (3DPD) angiography has been used for the evaluation of utero-placental vascularisation and three vascular indices have been calculated: the vascularisation index (VI), flow index (FI) and vascularisation-FI (VFI). However, several technical endpoints hinder the clinical use of 3DPD as physical characteristics and machine settings may affect 3DPD indices, and so its clinical significance is not yet clear. Objectives The primary objective is to better understand the clinical significance of 3DPD indices by evaluating the relationship between these indices and placental morphometry. Secondary objectives are (i) to determine the impact of machine settings and physical characteristics on 3DPD indices, and (ii) to evaluate physio-pathological placental vascularisation patterns. Methods and analysis This is a prospective controlled study. We expect to include 112 women: 84 with normal pregnancies and 28 with PE and/or IUGR (based on our former cohort study on 3DPD indices for PE and/or IUGR prediction (unpublished data)). Within 72 h before planned or semi-urgent caesarean section, utero-placental 3DPD images with five different machine settings will be acquired. Placentas will be collected and examined after surgery and stereological indices (volume density, surface density, length density) calculated. The 3DPD indices (VI, FI and VFI) of the placenta and adjacent myometrium will be calculated. Correlation between Doppler and morphological indices will be evaluated by Pearson or Spearman tests. Agreement between 3DPD indices and morphological indices will be assessed by Bland and Altman plots. The impact of Doppler settings and maternal characteristics on 3DPD indices will be evaluated with a multivariate linear regression model. Ethics The study and related consent forms have

  7. Molecular identification of Nocardia species using the sodA gene: Identificación molecular de especies de Nocardia utilizando el gen sodA.

    PubMed

    Sánchez-Herrera, K; Sandoval, H; Mouniee, D; Ramírez-Durán, N; Bergeron, E; Boiron, P; Sánchez-Saucedo, N; Rodríguez-Nava, V

    2017-09-01

    Currently for bacterial identification and classification the rrs gene encoding 16S rRNA is used as a reference method for the analysis of strains of the genus Nocardia. However, it does not have enough polymorphism to differentiate them at the species level. This fact makes it necessary to search for molecular targets that can provide better identification. The sodA gene (encoding the enzyme superoxide dismutase) has had good results in identifying species of other Actinomycetes. In this study the sodA gene is proposed for the identification and differentiation at the species level of the genus Nocardia. We used 41 type species of various collections; a 386 bp fragment of the sodA gene was amplified and sequenced, and a phylogenetic analysis was performed comparing the genes rrs (1171 bp), hsp65 (401 bp), secA1 (494 bp), gyrB (1195 bp) and rpoB (401 bp). The sequences were aligned using the Clustal X program. Evolutionary trees according to the neighbour-joining method were created with the programs Phylo_win and MEGA 6. The specific variability of the sodA genus of the genus Nocardia was analysed. A high phylogenetic resolution, significant genetic variability, and specificity and reliability were observed for the differentiation of the isolates at the species level. The polymorphism observed in the sodA gene sequence contains variable regions that allow the discrimination of closely related Nocardia species. The clear specificity, despite its small size, proves to be of great advantage for use in taxonomic studies and clinical diagnosis of the genus Nocardia.

  8. Detección automática de NEOs en imágenes CCD utilizando la transformada de Hough

    NASA Astrophysics Data System (ADS)

    Ruétalo, M.; Tancredi, G.

    El interés y la dedicación por los objetos que se acercan a la órbita de la Tierra (NEOs) ha aumentado considerablemente en los últimos años, tanto que se han iniciado varias campañas de búsqueda sistemática para aumentar la población identificada de éstos. El uso de placas fotográficas e identificación visual está siendo sustituído, progresivamente, por el uso de cámaras CCD y paquetes de detección automática de los objetos en las imágenes digitales. Una parte muy importante para la implementación exitosa de un programa automatizado de detección de este tipo es el desarrollo de algoritmos capaces de identificar objetos de baja relación señal-ruido y con requerimientos computacionales no elevados. En el presente trabajo proponemos la utilización de la transformada de Hough (utilizada en algunas áreas de visión artificial) para detectar automáticamente trazas, aproximadamente rectilíneas y de baja relación señal-ruido, en imágenes CCD. Desarrollamos una primera implementación de un algoritmo basado en ésta y lo probamos con una serie de imágenes reales conteniendo trazas con picos de señales de entre ~1 σ y ~3 σ por encima del nivel del ruido de fondo. El algoritmo detecta, sin inconvenientes, la mayoría de los casos y en tiempos razonablemente adecuados.

  9. Factibilidad de aplicación del test cosmológico de Alcock-Paczyski utilizando vacíos cósmicos

    NASA Astrophysics Data System (ADS)

    Correa, C. M.; Paz, D.; Padilla, N.; Angulo, R.

    2017-10-01

    We designed a version of the Alcock-Paczyński cosmological test using the void-galaxy cross-correlation function in redshift space. For this purpose, we developed a model that reproduces the geometric and dynamical distortions observed on the correlation isocontours, which allow to extract cosmological information. The model fundamentally depends on the matter density parameter, , and the redshift of the voids, . In order to calibrate the test, we used the Millennium XXL Simulation. Specifically, we evaluated the sensitivity of the fitting process as a function of redshift covering a wide range: , in view of the depth of the new generation of galaxy surveys.

  10. Role of p21 as a determinant of 1,6-Bis[4-(4-amino-3-hydroxyphenoxy)phenyl] diamantane response in human HCT-116 colon carcinoma cells.

    PubMed

    Wang, Jane-Jen; Hung, Hui-Fang; Huang, Min-Li; Lee, Hui-Ju; Chern, Yaw-Terng; Chang, Yuh-Fang; Chi, Chin-Wen; Hsu, Yi-Chiung

    2012-02-01

    1,6-Bis[4-(4-amino-3-hydroxyphenoxy)phenyl]diamantane (DPD) induces growth inhibition in human cancer cells. In our previous study, we discovered that DPD irreversibly inhibits the growth of Colo 205 colon cancer cells at the G0/G1 phase and induces cell differentiation. However, the detailed mechanism is still unknown. In this study, we examined the functional importance of p21 and p53 in DPD-induced anticancer effects. We used three isogenic cell lines, HCT-116, HCT-116 p53-/- and HCT-116 p21-/-, to evaluate the roles of p21 and p53 in the in vitro anticancer effects of DPD. The in vivo anti-proliferative effect of DPD was demonstrated by HCT-116 and HCT-116 p21-/- xenograft models. DPD significantly inhibited the growth as well as increased the number of HCT-116 cells in the G0/G1 phase, but not in HCT-116 p53-/- and HCT-116 p21-/- cells examined by flow cytometry. Additionally, western blot analysis showed that DPD treatment induced p21, but not p53 protein expression in HCT-116 cells. The p21-associated cell cycle regulated proteins, such as cyclin D, CDK4 and pRb were decreased after DPD treatment in HCT-116 cells. The DPD-increased G0/G1 phase and induced cell cycle regulated protein expression were not observed in HCT-116 p21-/- and HCT-116 p53-/- cells. DPD decreased cell migration in HCT-116 and HCT-116 p53-/- but not in HCT-116 p21-/- cells. p21 was required for the DPD-induced in vitro anti-colon cancer effect. The in vivo study also showed that DPD significantly inhibited tumor growth through p21 signaling. Our results clearly demonstrate that DPD-induced in vitro and in vivo anticancer effects through the activation of p21 in HCT-116 cells.

  11. Striking Discrepancy of Anomalous Body Experiences with Normal Interoceptive Accuracy in Depersonalization-Derealization Disorder

    PubMed Central

    Michal, Matthias; Reuchlein, Bettina; Adler, Julia; Reiner, Iris; Beutel, Manfred E.; Vögele, Claus; Schächinger, Hartmut; Schulz, André

    2014-01-01

    Background Disembodiment is a core feature of depersonalization disorder (DPD). Given the narratives of DPD patients about their disembodiment and emotional numbing and neurobiological findings of an inhibition of insular activity, DPD may be considered as a mental disorder with specific impairments of interoceptive awareness and body perception. Methods We investigated cardioceptive accuracy (CA) of DPD patients (n = 24) as compared to healthy controls (n = 26) with two different heartbeat detection tasks (“Schandry heartbeat counting task” and “Whitehead heartbeat discrimination task”). Self-rated clearness of body perception was measured by questionnaire. Results Contrary to our hypothesis, DPD patients performed similarly to healthy controls on the two different heartbeat detection tasks, and they had equal scores regarding their self-rated clearness of body perception. There was no correlation of the severity of “anomalous body experiences” and depersonalization with measures of interoceptive accuracy. Only among healthy controls CA in the Schandry task was positively correlated with self-rated clearness of body perception. Depersonalization was unrelated to severity of depression or anxiety, while depression and anxiety were highly correlated. Anxiety and depression did not modify the associations of depersonalization with interoceptive accuracy. Conclusions Our main findings highlight a striking discrepancy of normal interoception with overwhelming experiences of disembodiment in DPD. This may reflect difficulties of DPD patients to integrate their visceral and bodily perceptions into a sense of their selves. This problem may be considered an important target for psychotherapeutic treatment approaches. PMID:24587061

  12. Effect of graphite particle size and content on the formation mechanism of detonation polycrystalline diamond

    NASA Astrophysics Data System (ADS)

    Tong, Y.; Cao, Y.; Liu, R.; Shang, S. Y.; Huang, F. L.

    2017-05-01

    The formation mechanism of detonation polycrystalline diamond (DPD) generated from the detonation of a mixed RDX/graphite explosive is investigated. It is found experimentally that the DPD conversion rate decreases with both the content and the particle size of the graphite. Moreover, the particle sizes of the generated DPD powder are analyzed, which shows that, with the decrease in the graphite particle size, the mean number diameter of DPD decreases, but the mean volume diameter increases. In addition, with the help of scanning electron microscopy, it is observed that the in situ phase change occurs in the graphite particles, by which the small particles combine to form numerous large DPD particles. Based on both the experimental data and the classical ZND detonation model, we divide such a DPD synthesis process into two stages: In the first stage, the in situ phase change from graphite to diamond is dominant, supplemented by some coalescence growth at high pressure and temperature, which is affected mainly by the detonation performance of the mixed explosive under consideration. In the second stage, the graphitization of DPD caused by the residual heat is dominant, which is affected mainly by the unloading rate of the particle temperature.

  13. Shock Simulations of Single-Site Coarse-Grain RDX using the Dissipative Particle Dynamics Method with Reactivity

    NASA Astrophysics Data System (ADS)

    Sellers, Michael; Lisal, Martin; Schweigert, Igor; Larentzos, James; Brennan, John

    2015-06-01

    In discrete particle simulations, when an atomistic model is coarse-grained, a trade-off is made: a boost in computational speed for a reduction in accuracy. Dissipative Particle Dynamics (DPD) methods help to recover accuracy in viscous and thermal properties, while giving back a small amount of computational speed. One of the most notable extensions of DPD has been the introduction of chemical reactivity, called DPD-RX. Today, pairing the current evolution of DPD-RX with a coarse-grained potential and its chemical decomposition reactions allows for the simulation of the shock behavior of energetic materials at a timescale faster than an atomistic counterpart. In 2007, Maillet et al. introduced implicit chemical reactivity in DPD through the concept of particle reactors and simulated the decomposition of liquid nitromethane. We have recently extended the DPD-RX method and have applied it to solid hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) under shock conditions using a recently developed single-site coarse-grain model and a reduced RDX decomposition mechanism. A description of the methods used to simulate RDX and its tranition to hot product gases within DPD-RX will be presented. Additionally, examples of the effect of microstructure on shock behavior will be shown. Approved for public release. Distribution is unlimited.

  14. A liver stress-endocrine nexus promotes metabolic integrity during dietary protein dilution.

    PubMed

    Maida, Adriano; Zota, Annika; Sjøberg, Kim A; Schumacher, Jonas; Sijmonsma, Tjeerd P; Pfenninger, Anja; Christensen, Marie M; Gantert, Thomas; Fuhrmeister, Jessica; Rothermel, Ulrike; Schmoll, Dieter; Heikenwälder, Mathias; Iovanna, Juan L; Stemmer, Kerstin; Kiens, Bente; Herzig, Stephan; Rose, Adam J

    2016-09-01

    Dietary protein intake is linked to an increased incidence of type 2 diabetes (T2D). Although dietary protein dilution (DPD) can slow the progression of some aging-related disorders, whether this strategy affects the development and risk for obesity-associated metabolic disease such as T2D is unclear. Here, we determined that DPD in mice and humans increases serum markers of metabolic health. In lean mice, DPD promoted metabolic inefficiency by increasing carbohydrate and fat oxidation. In nutritional and polygenic murine models of obesity, DPD prevented and curtailed the development of impaired glucose homeostasis independently of obesity and food intake. DPD-mediated metabolic inefficiency and improvement of glucose homeostasis were independent of uncoupling protein 1 (UCP1), but required expression of liver-derived fibroblast growth factor 21 (FGF21) in both lean and obese mice. FGF21 expression and secretion as well as the associated metabolic remodeling induced by DPD also required induction of liver-integrated stress response-driven nuclear protein 1 (NUPR1). Insufficiency of select nonessential amino acids (NEAAs) was necessary and adequate for NUPR1 and subsequent FGF21 induction and secretion in hepatocytes in vitro and in vivo. Taken together, these data indicate that DPD promotes improved glucose homeostasis through an NEAA insufficiency-induced liver NUPR1/FGF21 axis.

  15. On the importance of shear dissipative forces in coarse-grained dynamics of molecular liquids.

    PubMed

    Izvekov, Sergei; Rice, Betsy M

    2015-04-28

    In this work we demonstrate from first principles that the shear frictions describing dissipative forces in the direction normal to the vector connecting the coarse-grained (CG) particles in dissipative particle dynamics (DPD) could be dominant for certain real molecular liquids at high-resolution coarse-graining. This is in contrast to previous works on bottom-up DPD modeling and indicates that such liquids cannot be simulated accurately using the conventional form of DPD which relies only on frictions in the radial direction. Specifically, we describe the development of fully bottom-up CG models for liquid hexahydro-1,3,5-trinitro-s-triazine (RDX) which are incorporated into the DPD method. Consistent with the microscopic foundation of DPD dynamics, the conservative part of the DPD models is obtained by the multi-scale coarse-graining (MS-CG) approach, which implements the pairwise decomposition of the atomistic potential of mean force (PMF) in CG coordinates. The radial and shear distant-dependent friction coefficients in a parameter-free form are derived systematically from microscopic velocity and force correlation data along system trajectories using a recently proposed approach [J. Chem. Phys., 2014, 140, 104104]. The shear dissipative forces for the reported system appear to be dominant. We discuss the implications of dominant shear dissipation on dynamical and transport properties of CG liquids such as diffusion and viscosity as revealed by simulations of liquid RDX using the new MS-CG/DPD models.

  16. A liver stress-endocrine nexus promotes metabolic integrity during dietary protein dilution

    PubMed Central

    Maida, Adriano; Zota, Annika; Sjøberg, Kim A.; Sijmonsma, Tjeerd P.; Pfenninger, Anja; Christensen, Marie M.; Gantert, Thomas; Fuhrmeister, Jessica; Rothermel, Ulrike; Schmoll, Dieter; Heikenwälder, Mathias; Iovanna, Juan L.; Stemmer, Kerstin; Herzig, Stephan; Rose, Adam J.

    2016-01-01

    Dietary protein intake is linked to an increased incidence of type 2 diabetes (T2D). Although dietary protein dilution (DPD) can slow the progression of some aging-related disorders, whether this strategy affects the development and risk for obesity-associated metabolic disease such as T2D is unclear. Here, we determined that DPD in mice and humans increases serum markers of metabolic health. In lean mice, DPD promoted metabolic inefficiency by increasing carbohydrate and fat oxidation. In nutritional and polygenic murine models of obesity, DPD prevented and curtailed the development of impaired glucose homeostasis independently of obesity and food intake. DPD-mediated metabolic inefficiency and improvement of glucose homeostasis were independent of uncoupling protein 1 (UCP1), but required expression of liver-derived fibroblast growth factor 21 (FGF21) in both lean and obese mice. FGF21 expression and secretion as well as the associated metabolic remodeling induced by DPD also required induction of liver-integrated stress response–driven nuclear protein 1 (NUPR1). Insufficiency of select nonessential amino acids (NEAAs) was necessary and adequate for NUPR1 and subsequent FGF21 induction and secretion in hepatocytes in vitro and in vivo. Taken together, these data indicate that DPD promotes improved glucose homeostasis through an NEAA insufficiency–induced liver NUPR1/FGF21 axis. PMID:27548521

  17. Modeling of advection-diffusion-reaction processes using transport dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Yazdani, Alireza; Tartakovsky, Alexandre; Karniadakis, George Em

    2015-11-01

    We present a transport dissipative particle dynamics (tDPD) model for simulating mesoscopic problems involving advection-diffusion-reaction (ADR) processes, along with a methodology for implementation of the correct Dirichlet and Neumann boundary conditions in tDPD simulations. In particular, the transport of concentration is modeled by a Fickian flux and a random flux between tDPD particles, and the advection is implicitly considered by the movements of Lagrangian particles. To validate the proposed tDPD model and the boundary conditions, three benchmark simulations of one-dimensional diffusion with different boundary conditions are performed, and the results show excellent agreement with the theoretical solutions. Also, two-dimensional simulations of ADR systems are performed and the tDPD simulations agree well with the results obtained by the spectral element method. Finally, an application of tDPD to the spatio-temporal dynamics of blood coagulation involving twenty-five reacting species is performed to demonstrate the promising biological applications of the tDPD model. Supported by the DOE Center on Mathematics for Mesoscopic Modeling of Materials (CM4) and an INCITE grant.

  18. The Impact of the Expression Level of Intratumoral Dihydropyrimidine Dehydrogenase on Chemotherapy Sensitivity and Survival of Patients in Gastric Cancer: A Meta-Analysis

    PubMed Central

    Zhang, Cong; Liu, Hongpeng; Ma, Bin; Song, Yongxi; Gao, Peng; Xu, Yingying; Yu, Dehao

    2017-01-01

    The potential impact that the intratumoral expression level of dihydropyrimidine dehydrogenase (DPD) has on chemotherapy sensitivity and long-term survival for gastric cancer (GC) patients remains controversial; therefore, this study seeks to clarify this issue. Our meta-analysis was performed using Review Manager (RevMan) 5.3 software. In vitro drug sensitivity tests, correlation coefficients between sensitivity to 5-fluorouracil (5-FU), and expression levels of intratumoral DPD were used as effective indexes to analyse. Overall survival (OS) and progression-free survival (PFS) were used as endpoints for patient outcome, and hazard ratios (HRs) and 95% confidence intervals (CIs) were noted as measures of effect. There were 15 eligible studies including 1805 patients for the final analysis. The analysis revealed a statistically significant difference between the expression level of intratumoral DPD activity, DPD mRNA levels, and sensitivity to 5-FU in GC patients, with high expression levels of intratumoral DPD resulting in low sensitivity to 5-FU. However, no matter what therapeutic regimens were used, there was no significant difference for patient outcomes between high and low DPD expression groups, either in OS or in PFS. In conclusion, high levels of intratumoral DPD expression have a negative impact on sensitivity to 5-FU in GC patients, but no prognostic value for long-term survival was uncovered. PMID:28255193

  19. Novel disease-causing mutations in the dihydropyrimidine dehydrogenase gene interpreted by analysis of the three-dimensional protein structure.

    PubMed Central

    van Kuilenburg, André B P; Dobritzsch, Doreen; Meinsma, Rutger; Haasjes, Janet; Waterham, Hans R; Nowaczyk, Malgorzata J M; Maropoulos, George D; Hein, Guido; Kalhoff, Hermann; Kirk, Jean M; Baaske, Holger; Aukett, Anne; Duley, John A; Ward, Kate P; Lindqvist, Ylva; van Gennip, Albert H

    2002-01-01

    Dihydropyrimidine dehydrogenase (DPD) deficiency is an autosomal recessive disease characterized by thymine-uraciluria in homozygous deficient patients. Cancer patients with a partial deficiency of DPD are at risk of developing severe life-threatening toxicities after the administration of 5-fluorouracil. Thus, identification of novel disease-causing mutations is of the utmost importance to allow screening of patients at risk. In eight patients presenting with a complete DPD deficiency, a considerable variation in the clinical presentation was noted. Whereas motor retardation was observed in all patients, no patients presented with convulsive disorders. In this group of patients, nine novel mutations were identified including one deletion of two nucleotides [1039-1042delTG] and eight missense mutations. Analysis of the crystal structure of pig DPD suggested that five out of eight amino acid exchanges present in these patients with a complete DPD deficiency, Pro86Leu, Ser201Arg, Ser492Leu, Asp949Val and His978Arg, interfered directly or indirectly with cofactor binding or electron transport. Furthermore, the mutations Ile560Ser and Tyr211Cys most likely affected the structural integrity of the DPD protein. Only the effect of the Ile370Val and a previously identified Cys29Arg mutation could not be readily explained by analysis of the three-dimensional structure of the DPD enzyme, suggesting that at least the latter might be a common polymorphism. Our data demonstrate for the first time the possible consequences of missense mutations in the DPD gene on the function and stability of the DPD enzyme. PMID:11988088

  20. Dihydropyrimidine Dehydrogenase Is a Prognostic Marker for Mesenchymal Stem Cell-Mediated Cytosine Deaminase Gene and 5-Fluorocytosine Prodrug Therapy for the Treatment of Recurrent Gliomas.

    PubMed

    Chung, Taemoon; Na, Juri; Kim, Young-Il; Chang, Da-Young; Kim, Young Il; Kim, Hyeonjin; Moon, Ho Eun; Kang, Keon Wook; Lee, Dong Soo; Chung, June-Key; Kim, Sung-Soo; Suh-Kim, Haeyoung; Paek, Sun Ha; Youn, Hyewon

    2016-01-01

    We investigated a therapeutic strategy for recurrent malignant gliomas using mesenchymal stem cells (MSC), expressing cytosine deaminase (CD), and prodrug 5-Fluorocytosine (5-FC) as a more specific and less toxic option. MSCs are emerging as a novel cell therapeutic agent with a cancer-targeting property, and CD is considered a promising enzyme in cancer gene therapy which can convert non-toxic 5-FC to toxic 5-Fluorouracil (5-FU). Therefore, use of prodrug 5-FC can minimize normal cell toxicity. Analyses of microarrays revealed that targeting DNA damage and its repair is a selectable option for gliomas after the standard chemo/radio-therapy. 5-FU is the most frequently used anti-cancer drug, which induces DNA breaks. Because dihydropyrimidine dehydrogenase (DPD) was reported to be involved in 5-FU metabolism to block DNA damage, we compared the survival rate with 5-FU treatment and the level of DPD expression in 15 different glioma cell lines. DPD-deficient cells showed higher sensitivity to 5-FU, and the regulation of DPD level by either siRNA or overexpression was directly related to the 5-FU sensitivity. For MSC/CD with 5-FC therapy, DPD-deficient cells such as U87MG, GBM28, and GBM37 showed higher sensitivity compared to DPD-high U373 cells. Effective inhibition of tumor growth was also observed in an orthotopic mouse model using DPD- deficient U87MG, indicating that DPD gene expression is indeed closely related to the efficacy of MSC/CD-mediated 5-FC therapy. Our results suggested that DPD can be used as a biomarker for selecting glioma patients who may possibly benefit from this therapy.

  1. Dihydropyrimidine Dehydrogenase Is a Prognostic Marker for Mesenchymal Stem Cell-Mediated Cytosine Deaminase Gene and 5-Fluorocytosine Prodrug Therapy for the Treatment of Recurrent Gliomas

    PubMed Central

    Chung, Taemoon; Na, Juri; Kim, Young-il; Chang, Da-Young; Kim, Young Il; Kim, Hyeonjin; Moon, Ho Eun; Kang, Keon Wook; Lee, Dong Soo; Chung, June-Key; Kim, Sung-Soo; Suh-Kim, Haeyoung; Paek, Sun Ha; Youn, Hyewon

    2016-01-01

    We investigated a therapeutic strategy for recurrent malignant gliomas using mesenchymal stem cells (MSC), expressing cytosine deaminase (CD), and prodrug 5-Fluorocytosine (5-FC) as a more specific and less toxic option. MSCs are emerging as a novel cell therapeutic agent with a cancer-targeting property, and CD is considered a promising enzyme in cancer gene therapy which can convert non-toxic 5-FC to toxic 5-Fluorouracil (5-FU). Therefore, use of prodrug 5-FC can minimize normal cell toxicity. Analyses of microarrays revealed that targeting DNA damage and its repair is a selectable option for gliomas after the standard chemo/radio-therapy. 5-FU is the most frequently used anti-cancer drug, which induces DNA breaks. Because dihydropyrimidine dehydrogenase (DPD) was reported to be involved in 5-FU metabolism to block DNA damage, we compared the survival rate with 5-FU treatment and the level of DPD expression in 15 different glioma cell lines. DPD-deficient cells showed higher sensitivity to 5-FU, and the regulation of DPD level by either siRNA or overexpression was directly related to the 5-FU sensitivity. For MSC/CD with 5-FC therapy, DPD-deficient cells such as U87MG, GBM28, and GBM37 showed higher sensitivity compared to DPD-high U373 cells. Effective inhibition of tumor growth was also observed in an orthotopic mouse model using DPD- deficient U87MG, indicating that DPD gene expression is indeed closely related to the efficacy of MSC/CD-mediated 5-FC therapy. Our results suggested that DPD can be used as a biomarker for selecting glioma patients who may possibly benefit from this therapy. PMID:27446484

  2. No-slip boundary condition in finite-size dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Ranjith, S. Kumar; Patnaik, B. S. V.; Vedantam, Srikanth

    2013-01-01

    Dissipative particle dynamics (DPD) is an efficient, particle based mesoscopic numerical scheme to simulate dynamics of complex fluids and micro-flows, with spatio-temporal scales in the range of micrometers and microseconds. While the traditional DPD method treated particles as point masses, a modified DPD scheme was introduced recently [W. Pan, I.V. Pivkin, G.E. Karniadakis, Single-particle hydrodynamics in DPD: a new formulation, Europhysics Letters 84 (2008) 10012] by including transverse forces between finite sized particles in addition to the central forces of the standard DPD. The capability of a DPD scheme to solve confined wall bounded flows, depends on its ability to model the flow boundaries and effectively impose the classical no-slip boundary condition. Previous simulations with the modified DPD scheme used boundary conditions from the traditional DPD schemes, resorting to the velocity reversal of re-inserted particles which cross the solid wall. In the present work, a new method is proposed to impose no-slip or tunable slip boundary condition by controlling the non-central dissipative components in the modified DPD scheme. The solid wall is modeled in such a way that the fluid particles feel the presence of a continuous wall rather than a few discrete frozen particles as in conventional wall models. The fluid particles interact with the walls using a modified central repulsive potential to reduce the spurious density fluctuations. Several different benchmark problems (Poiseuille flow, lid-driven cavity and flow past circular cylinder) were solved using the new approach to demonstrate its validity.

  3. Dissipative Particle Dynamics at Isoenergetic Conditions Using Shardlow-Like Splitting Algorithms

    DTIC Science & Technology

    2013-09-01

    Fpp F p rr Fpp . (13) The following outline summarizes a practical implementation of the SSA-VV for the DPD-E variant. 1...1 (i) Ciii t Fpp 2   (ii) i i ii m t prr  3. Conservative Force Calculation:  NiCi 1F 4. Deterministic Integration #2 for Ni...1 C iii t Fpp 2   3. Computational Details The SSA-VV for the DPD-E variant was tested using both the standard DPD fluid (6) and a

  4. Dysgenetic polycystic disease of the parotid gland: Report of a case and review of the literature

    PubMed Central

    Kumar, KR Ashok; Mahadesh, Jyothi; Setty, Suhas

    2013-01-01

    Dysgenetic polycystic disease (DPD) is a rare cystic lesion affecting mainly the parotid salivary glands with only 14 reported cases in English literature. DPD of parotids is more common in females, common in younger age group, mostly bilateral in occurrence and commonly affects the superficial lobe. Surgery is performed for symptomatic relief and cosmosis. We report a case of a unilateral DPD of the parotid gland with distinctive histopathology. Patient was treated by performing total parotidectomy with preservation of the facial nerve. PMID:24250087

  5. Defensin of the zebra mussel (Dreissena polymorpha): molecular structure, in vitro expression, antimicrobial activity, and potential functions.

    PubMed

    Xu, Wei; Faisal, Mohamed

    2010-07-01

    A 409 bp full length defensin gene was cloned and sequenced based on an expressed sequence tag (EST) obtained from a normalized zebra mussel (Dreissena polymorpha) foot cDNA library developed in our laboratory. The D. polymorpha defensin (Dpd) gene encoded a peptide with 76 amino acid residues. The mature Dpd contains 54 amino acids with a fully functional insect defensin A domain. Homologue searching against GenBank database suggested that this Dpd was phylogenetically close to defensins from a group of insects with six conserved cysteine residues. Predicted with homology-modeling method, the three-dimensional structure of Dpd also demonstrated a significant similarity with insect defensin A. The recombinant Dpd was in vitro expressed through an Escherichia coli expression system. The antimicrobial activities of the refolded recombinant Dpd were found against the growth of Morganella sp., Plesiomonas shigelloides, Edwardsiella tarda, E. coli and Staphylococcus aureus aureus (ATCC12598) with the minimal inhibition concentration (MIC) 0.35, 0.43, 1.16, 6.46, and 30.39 microM, respectively. However, with less than 50 microM no detectable inhibition activities were observed against the other four Gram-negative bacteria (Aeromonas salmonicida salmonicida, Motile Aeromonas, Flavobacterium sp., Pseudomonas fluorescens, Shewanella putrifaciens), as well as the other Gram-positive bacteria (Bacillus megaterium ATCC14581, Carnobacterium maltaromaticum ATCC27865, Enterococcus faecalis ATCC19433, and Micrococcus leteus ATCC4698), and the yeast Saccharomyces cerevisiae. The RNA fluorescent in situ hybridization (FISH) of Dpd in the zebra mussel suggested that the Dpd was expressed in a variety of tissues, such as foot, retractor muscle, ctenidium, mantle, hemocytes, gonad, digestive gland, and intestine. By using the quantitative PCR, the expression level of Dpd in the zebra mussel foot was the highest, followed by the muscle. By comparing the amount of Dpd transcripts in the

  6. A mesoscopic simulation of material ---Advances in Dissipative particle dynamics research

    NASA Astrophysics Data System (ADS)

    Xue, Zhaolin

    2017-09-01

    A mesoscopic simulation of material --Dissipative particle dynamics(DPD), as the bond between macroscopic and microscopic simulation, had been increasingly draw attention in the research of soft matters, including the flowing condition and the morphological structure. The method of DPD simulation had been applied extensively in the fields of soft matters such as biomacromolecule and the flows of polymers since the DPD simulation has an advantage in time and space scale. In this article, the origin, the theoretical model and the development of dissipative particle dynamics are introduced at first. Subsequently, the advances in the simulation of complex fluids and polymers are reviewed. Finally, the future development and application are concluded.

  7. Dissipative Particle Dynamics interaction parameters from ab initio calculations

    NASA Astrophysics Data System (ADS)

    Sepehr, Fatemeh; Paddison, Stephen J.

    2016-02-01

    Dissipative Particle Dynamics (DPD) is a commonly employed coarse-grained method to model complex systems. Presented here is a pragmatic approach to connect atomic-scale information to the meso-scale interactions defined between the DPD particles or beads. Specifically, electronic structure calculations were utilized for the calculation of the DPD pair-wise interaction parameters. An implicit treatment of the electrostatic interactions for charged beads is introduced. The method is successfully applied to derive the parameters for a hydrated perfluorosulfonic acid ionomer with absorbed vanadium cations.

  8. A stochastic boundary forcing for dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Altenhoff, Adrian M.; Walther, Jens H.; Koumoutsakos, Petros

    2007-07-01

    The method of dissipative particle dynamics (DPD) is an effective, coarse grained model of the hydrodynamics of complex fluids. DPD simulations of wall-bounded flows are however often associated with spurious fluctuations of the fluid properties near the wall. We present a novel stochastic boundary forcing for DPD simulations of wall-bounded flows, based on the identification of fluctuations in simulations of the corresponding homogeneous system at equilibrium. The present method is shown to enforce accurately the no-slip boundary condition, while minimizing spurious fluctuations of material properties, in a number of benchmark problems.

  9. Implicit and self-attributed dependency needs in dependent and histrionic personality disorders.

    PubMed

    Bornstein, R F

    1998-08-01

    Theorists speculate that dependent personality disorder (DPD) and histrionic personality disorder (HPD) are both associated with high levels of implicit (i.e., unconscious) dependency needs but speculate that only DPD is associated with high levels of self-attributed (i.e., conscious) dependency needs. To test this hypothesis, 444 undergraduates (236 women and 208 men) completed the Personality Diagnostic Questionnaire-Revised (PDQ-R), along with widely used measures of implicit dependency needs (the Rorschach Oral Dependency Scale; ROD), and self-attributed dependency needs (the Interpersonal Dependency Inventory; IDI). Correlational analyses and comparisons of IDI and ROD scores in participants scoring above and below the PDQ-R DPD and HPD thresholds supported theorists' speculations regarding implicit and self-attributed dependency needs in DPD and HPD. Implications of these results are discussed, and suggestions for future studies are offered.

  10. Determination of macroscopic transport coefficients of a dissipative particle dynamics solvent

    NASA Astrophysics Data System (ADS)

    Azarnykh, Dmitrii; Litvinov, Sergey; Bian, Xin; Adams, Nikolaus A.

    2016-01-01

    We present an approach to determine macroscopic transport coefficients of a dissipative particle dynamics (DPD) solvent. Shear viscosity, isothermal speed of sound, and bulk viscosity result from DPD-model input parameters and can be determined only a posteriori. For this reason approximate predictions of these quantities are desirable in order to set appropriate DPD input parameters. For the purpose of deriving an improved approximate prediction we analyze the autocorrelation of shear and longitudinal modes in Fourier space of a DPD solvent for Kolmogorov flow. We propose a fitting function with nonexponential properties which gives a good approximation to these autocorrelation functions. Given this fitting function we improve significantly the capability of a priori determination of macroscopic solvent transport coefficients in comparison to previously used exponential fitting functions.

  11. Pairwise adaptive thermostats for improved accuracy and stability in dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Leimkuhler, Benedict; Shang, Xiaocheng

    2016-11-01

    We examine the formulation and numerical treatment of dissipative particle dynamics (DPD) and momentum-conserving molecular dynamics. We show that it is possible to improve both the accuracy and the stability of DPD by employing a pairwise adaptive Langevin thermostat that precisely matches the dynamical characteristics of DPD simulations (e.g., autocorrelation functions) while automatically correcting thermodynamic averages using a negative feedback loop. In the low friction regime, it is possible to replace DPD by a simpler momentum-conserving variant of the Nosé-Hoover-Langevin method based on thermostatting only pairwise interactions; we show that this method has an extra order of accuracy for an important class of observables (a superconvergence result), while also allowing larger timesteps than alternatives. All the methods mentioned in the article are easily implemented. Numerical experiments are performed in both equilibrium and nonequilibrium settings; using Lees-Edwards boundary conditions to induce shear flow.

  12. Assignment of the human dihydropyrimidine dehydrogenase gene (DPYD) to chromosome region 1p22 by fluorescence in situ hybridization

    SciTech Connect

    Takai, Setsuo; Fernandez-Salguero, Pedro; Kimura, Shioko

    1994-12-01

    Dihydropyrimidine dehydrogenase (DPD, EC 1.3.1.2) is the initial and rate-limiting enzyme in the three-step pathway of uracil and thymine catabolism leading to the formation of {beta}-alanine and {beta}-aminobutyric acid, respectively. Several studies have demonstrated the importance of DPD in cancer patients, particularly in those lacking or having only low levels of activity. Patients exhibiting severe toxicity when administered 5-fluorouracil were shown to have low DPD activity. Studies of affected families demonstrated that the deficiency was inherited in an autosomal recessive pattern. DPD deficiency is one of several inherited disorders of pyrimidine metabolism, clinically termed thymine-uracil-uria. 14 refs., 1 fig.

  13. Nonlinearity mitigation for high-speed optical OFDM transmitters using digital pre-distortion.

    PubMed

    Bao, Yuan; Li, Zhaohui; Li, Jianping; Feng, Xinhuan; Guan, Bai-ou; Li, Guifang

    2013-03-25

    Optical orthogonal frequency-division multiplexing (OOFDM) signal is sensitive to nonlinear distortions induced by optical modulators. We propose and experimentally demonstrate a digital pre-distortion (DPD) algorithm to linearize the optical modulators including electro-absorption modulated lasers (EML) and Mach-Zehnder modulators (MZM) used in high-speed OOFDM transmitters. By using an adaptive DPD algorithm with a learning structure, the inverse transfer function of a modulator, which is based on a polynomial model, has been obtained. In the experiment, the performance improvements with and without considering the memory effects of the DPD model are illustrated. The two typical kinds of high-speed OOFDM signals with a bit rate up to 30-Gb/s have been implemented experimentally. The results show that the nonlinear distortion induced by optical modulators can be compensated by using the DPD algorithm to substantially improve the optical modulation index.

  14. Bone Markers

    MedlinePlus

    ... from the amino terminal end of the protein matrix; another marker used to monitor therapy. Deoxypyridinoline (DPD) – a collagen breakdown product with a ring structure. Pyridinium Crosslinks – a group of collagen breakdown products ...

  15. The Role of Cognitive-Behavioural Therapy for Patients with Depression in Parkinson's Disease

    PubMed Central

    Charidimou, Andreas; Seamons, John; Selai, Caroline; Schrag, Anette

    2011-01-01

    Depression is a common complication of Parkinson's disease (PD) with considerable impact on patients' quality of life. However, at present the most appropriate treatment approach is unclear. There are limited data on antidepressant medications in PD-associated depression (dPD) and those available suggest limited efficacy and tolerability of these drugs. Cognitive behavioural therapy (CBT) has been shown to be an effective treatment of depressive disorders. Treatment of dPD with CBT may pose particular challenges, including possible different pathophysiology, physical and mental comorbidities, and barriers to treatment through disability, which do not allow simple transfer of these results to patients with dPD. However, a number of case reports, case series, and small pilot studies suggest that this is a promising treatment for patients with PD. We here summarise the published evidence on this treatment in dPD. PMID:21766001

  16. Pairwise adaptive thermostats for improved accuracy and stability in dissipative particle dynamics

    SciTech Connect

    Leimkuhler, Benedict Shang, Xiaocheng

    2016-11-01

    We examine the formulation and numerical treatment of dissipative particle dynamics (DPD) and momentum-conserving molecular dynamics. We show that it is possible to improve both the accuracy and the stability of DPD by employing a pairwise adaptive Langevin thermostat that precisely matches the dynamical characteristics of DPD simulations (e.g., autocorrelation functions) while automatically correcting thermodynamic averages using a negative feedback loop. In the low friction regime, it is possible to replace DPD by a simpler momentum-conserving variant of the Nosé–Hoover–Langevin method based on thermostatting only pairwise interactions; we show that this method has an extra order of accuracy for an important class of observables (a superconvergence result), while also allowing larger timesteps than alternatives. All the methods mentioned in the article are easily implemented. Numerical experiments are performed in both equilibrium and nonequilibrium settings; using Lees–Edwards boundary conditions to induce shear flow.

  17. Dependent personality disorder: a critical review.

    PubMed

    Disney, Krystle L

    2013-12-01

    Dependent personality disorder (DPD) has evolved from an abstract idea rooted in a historic and psychoanalytic context to a codified diagnosis in the DSM-IV-TR. This comprehensive review paper chronicles the evolution of DPD through each version of the DSM. Major topics relevant to the disorder are also investigated, including gender and cultural considerations, stability and manifestations of DPD across different developmental stages, comorbidity issues, and others. The purpose of this review is to provide a broad yet comprehensive examination of the complex angles of maladaptive dependency and to identify essential next steps in furthering our knowledge of this disorder. The paper concludes with a discussion of shortcomings in the body of research relevant to DPD, along with specific suggestions for improvement in this field of study.

  18. A pivotal role for beta-aminoisobutyric acid and oxidative stress in dihydropyrimidine dehydrogenase deficiency?

    PubMed

    van Kuilenburg, A B P; Stroomer, A E M; Abeling, N G G M; van Gennip, A H

    2006-01-01

    Dihydropyrimidine dehydrogenase (DPD) constitutes the first step of the pyrimidine degradation pathway in which the pyrimidine bases uracil and thymine are catabolised to beta-alanine and beta-aminoisobutyric acid (beta-AIB), respectively. The mean concentration of beta-AIB was approximately 5- to 8-fold lower in urine of patients with a DPD deficiency, when compared to age-matched controls. Comparable levels of 8-hydroxydeoxyguanosine (8-OHdG) were present in urine from controls and DPD patients at the age <2 year. In contrast, slightly elevated levels of 8-OHdG were detected in urine from DPD patients with an age >2 year, suggesting the presence of increased oxidative stress.

  19. Dihydropyrimidine dehydrogenase mutation in neoadjuvant chemotherapy in head and neck cancers: Myth or reality?

    PubMed Central

    Patil, Vijay M.; Noronha, Vanita; Joshi, Amit; Zanwar, Saurabh; Ramaswamy, Anant; Arya, Supreeta; Mahajan, Abhishek; Bhattacharjee, Atanu; Prabhash, Kumar

    2016-01-01

    Purpose: The docetaxel, 5-fluorouracil (5-FU), and cisplatin (TPF) regimen in India is associated with high percentages of Grade 3–4 toxicity. This analysis was planned to evaluate the incidence of dihydropyrimidine dehydrogenase (DPD) mutation in patients with severe gastrointestinal toxicity, to assess whether the mutation could be predicted by a set of clinical criteria and whether it has any impact on postneoadjuvant chemotherapy response. Methods: All consecutive patients who received TPF regimen in head and neck cancers between January 2015 and April 2015 were selected. Patients who had predefined set of toxicities in Cycle 1 were selected for DPD mutation testing. Depending on the results, C2 doses were modified. Postcompletion of two cycles, patients underwent radiological response assessment. Descriptive statistics has been performed. The normally distributed continuous variables were compared by unpaired Student's t-test, whereas variables which were not normally distributed by Wilcoxon sum rank test. For noncontinuous variables, comparison was performed by Fisher's exact test. Results: Out of 34 patients, who received TPF, 12 were selected for DPD testing, and 11 (32.4%, 95% confidence interval [95% CI]: 19.1–49.3%) had DPD mutation. The predictive accuracy of the criteria for the tested DPD mutations was 81.3% (95% CI: 62.1–100%). Of the 11 DPD mutation positive patients, except for one patient, all others received the second cycle of TPF. The dose adjustments done in 5-FU were 50% dose reduction in 9 patients and no dose reduction in one patient. The response rate in DPD mutated patients was 27.3% (3/11) and that in DPD nonmutated/nontested was 39.1% (9/23) (P = 0.70). Conclusion: In this small study, it seems that the incidence of DPD mutation is more common in Indian then it's in the Caucasian population. Clinical toxicity criteria can accurately predict for DPD mutation. Postdose adjustments of 5-FU from C2 onward, TPF can safely be delivered

  20. Processing the Interspecies Quorum-sensing Signal Autoinducer-2 (AI-2)

    SciTech Connect

    J Marques; P Lamosa; C Russell; R Ventura; C Maycock; M Semmelhack; S Miller; K Xavier

    2011-12-31

    The molecule (S)-4,5-dihydroxy-2,3-pentanedione (DPD) is produced by many different species of bacteria and is the precursor of the signal molecule autoinducer-2 (AI-2). AI-2 mediates interspecies communication and facilitates regulation of bacterial behaviors such as biofilm formation and virulence. A variety of bacterial species have the ability to sequester and process the AI-2 present in their environment, thereby interfering with the cell-cell communication of other bacteria. This process involves the AI-2-regulated lsr operon, comprised of the Lsr transport system that facilitates uptake of the signal, a kinase that phosphorylates the signal to phospho-DPD (P-DPD), and enzymes (like LsrG) that are responsible for processing the phosphorylated signal. Because P-DPD is the intracellular inducer of the lsr operon, enzymes involved in P-DPD processing impact the levels of Lsr expression. Here we show that LsrG catalyzes isomerization of P-DPD into 3,4,4-trihydroxy-2-pentanone-5-phosphate. We present the crystal structure of LsrG, identify potential catalytic residues, and determine which of these residues affects P-DPD processing in vivo and in vitro. We also show that an lsrG deletion mutant accumulates at least 10 times more P-DPD than wild type cells. Consistent with this result, we find that the lsrG mutant has increased expression of the lsr operon and an altered profile of AI-2 accumulation and removal. Understanding of the biochemical mechanisms employed by bacteria to quench signaling of other species can be of great utility in the development of therapies to control bacterial behavior.

  1. Altered directional connectivity between emotion network and motor network in Parkinson's disease with depression

    PubMed Central

    Liang, Peipeng; Deshpande, Gopikrishna; Zhao, Sinan; Liu, Jiangtao; Hu, Xiaoping; Li, Kuncheng

    2016-01-01

    Abstract Depression is common in patients with Parkinson's disease (PD), which can make all the other symptoms of PD much worse. It is thus urgent to differentiate depressed PD (DPD) patients from non-depressed PD (NDPD). The purpose of the present study was to characterize alterations in directional brain connectivity unique to Parkinson's disease with depression, using resting state functional magnetic resonance imaging (rs-fMRI). Sixteen DPD patients, 20 NDPD patients, 17 patients with major depressive disorder (MDD) and 21 healthy control subjects (normal controls [NC]) underwent structural MRI and rs-fMRI scanning. Voxel-based morphometry and directional brain connectivity during resting-state were analyzed. Analysis of variance (ANOVA) and 2-sample t tests were used to compare each pair of groups, using sex, age, education level, structural atrophy, and/or HAMD, unified PD rating scale (UPDRS) as covariates. In contrast to NC, DPD showed significant gray matter (GM) volume abnormalities in some mid-line limbic regions including dorsomedial prefrontal cortex and precuneus, and sub-cortical regions including caudate and cerebellum. Relative to NC and MDD, both DPD and NDPD showed significantly increased directional connectivity from bilateral anterior insula and posterior orbitofrontal cortices to left inferior temporal cortex. As compared with NC, MDD and NDPD, alterations of directional connectivity in DPD were specifically observed in the pathway from bilateral anterior insula and posterior orbitofrontal cortices to right basal ganglia. Resting state directional connectivity alterations were observed between emotion network and motor network in DPD patients after controlling for age, sex, structural atrophy. Given that these alterations are unique to DPD, it may provide a potential differential biomarker for distinguishing DPD from NC, NDPD, and MDD. PMID:27472694

  2. Dissipative particle dynamics simulations in the grand canonical ensemble: applications to polymer brushes.

    PubMed

    Goujon, Florent; Malfreyt, Patrice; Tildesley, Dominic J

    2004-04-19

    We have used the dissipative particle dynamics (DPD) method in the grand canonical ensemble to study the compression of grafted polymer brushes in good solvent conditions. The force-distance profiles calculated from DPD simulations in the grand canonical ensemble are in very good agreement with the self-consistent field (SCF) theoretical models and with experimental results for two polystyrene brush layers grafted onto mica surfaces in toluene.

  3. Protocol Development and Equivalency Testing of the FACTS Procedure for Chlorine Residual Determination in Drinking Water.

    DTIC Science & Technology

    1984-03-15

    titration is capable of differentiating free chlorine (HOCl/OCI-), monochloramine (NH Cl), and dichloramine (NHC1 2 ) and is generally the method of choice...chlorine, Appendix D. A study has recently been reported that details the kinetics of monochloramine oxidation of DPD (19) and confirms the previous...studies ’*-- (5-13). From the kinetic expressions it was shown that the monochloramine interference with the DPD test is dependent in pH, monochloramine

  4. Processing the Interspecies Quorum-sensing Signal Autoinducer-2 (AI-2)

    PubMed Central

    Marques, João C.; Lamosa, Pedro; Russell, Caitlin; Ventura, Rita; Maycock, Christopher; Semmelhack, Martin F.; Miller, Stephen T.; Xavier, Karina B.

    2011-01-01

    The molecule (S)-4,5-dihydroxy-2,3-pentanedione (DPD) is produced by many different species of bacteria and is the precursor of the signal molecule autoinducer-2 (AI-2). AI-2 mediates interspecies communication and facilitates regulation of bacterial behaviors such as biofilm formation and virulence. A variety of bacterial species have the ability to sequester and process the AI-2 present in their environment, thereby interfering with the cell-cell communication of other bacteria. This process involves the AI-2-regulated lsr operon, comprised of the Lsr transport system that facilitates uptake of the signal, a kinase that phosphorylates the signal to phospho-DPD (P-DPD), and enzymes (like LsrG) that are responsible for processing the phosphorylated signal. Because P-DPD is the intracellular inducer of the lsr operon, enzymes involved in P-DPD processing impact the levels of Lsr expression. Here we show that LsrG catalyzes isomerization of P-DPD into 3,4,4-trihydroxy-2-pentanone-5-phosphate. We present the crystal structure of LsrG, identify potential catalytic residues, and determine which of these residues affects P-DPD processing in vivo and in vitro. We also show that an lsrG deletion mutant accumulates at least 10 times more P-DPD than wild type cells. Consistent with this result, we find that the lsrG mutant has increased expression of the lsr operon and an altered profile of AI-2 accumulation and removal. Understanding of the biochemical mechanisms employed by bacteria to quench signaling of other species can be of great utility in the development of therapies to control bacterial behavior. PMID:21454635

  5. Impact of 5-fluorouracil metabolizing enzymes on chemotherapy in patients with resectable colorectal cancer.

    PubMed

    Ochiai, Takumi; Umeki, Masahiko; Miyake, Hiroshi; Iida, Tatsumi; Okumura, Minoru; Ohno, Kazuhide; Sakamoto, Masashi; Miyoshi, Nobukazu; Takahashi, Masahiko; Tsumura, Hidenori; Tokunaga, Yukihiko; Naitou, Haruhiko; Fukui, Takuji

    2014-09-01

    Although 5-fluorouracil (5-FU) is an important drug for colorectal cancer (CRC) treatment, no useful biomarker is currently available to predict treatment response. Since 5-FU is converted into active or inactive forms by orotate phosphoribosyltransferase (OPRT) or dihydropyrimidine dehydrogenase (DPD), a correlation between these enzymes and response to 5-FU has been suggested. However, such a correlation has not been investigated prospectively. Therefore, in the present study, we aimed to prospectively evaluate whether OPRT and DPD were predictive factors of the response to 5-FU treatment in patients with resectable CRC. The present investigation was designed as a multicenter prospective cohort study. OPRT and DPD activities were assessed in biopsy samples, obtained surgically from patients with resectable CRC. The OPRT/DPD ratio was calculated and the cut-off values for this ratio were determined for 5-year disease-free survival (DFS) and overall survival (OS). Patients were treated with 5-FU/leucovorin (LV) regimens and oral 5-FU. The endpoint of this study was the correlation between the OPRT/DPD ratio and 5-year DFS and OS. The cut-off value for the OPRT/DPD ratio was determined by using the maximum χ2 statistic method against 5-year DFS and OS. Sixty-eight patients were enrolled from July 2003 to May 2005. The median follow-up period was 1925 days. The OPRT/DPD ratio cut-off values for 5-year DFS and OS were 0.015 and 0.013, respectively. During the 5-year DFS and OS periods, patients with higher cut-off values had a better prognosis than those with lower ratios (P=0.03 and 0.02, respectively). In conclusion, our results suggest that the OPRT/DPD ratio could be a predictive factor for response to 5-FU/LV adjuvant chemotherapy.

  6. Altered directional connectivity between emotion network and motor network in Parkinson's disease with depression.

    PubMed

    Liang, Peipeng; Deshpande, Gopikrishna; Zhao, Sinan; Liu, Jiangtao; Hu, Xiaoping; Li, Kuncheng

    2016-07-01

    Depression is common in patients with Parkinson's disease (PD), which can make all the other symptoms of PD much worse. It is thus urgent to differentiate depressed PD (DPD) patients from non-depressed PD (NDPD).The purpose of the present study was to characterize alterations in directional brain connectivity unique to Parkinson's disease with depression, using resting state functional magnetic resonance imaging (rs-fMRI).Sixteen DPD patients, 20 NDPD patients, 17 patients with major depressive disorder (MDD) and 21 healthy control subjects (normal controls [NC]) underwent structural MRI and rs-fMRI scanning. Voxel-based morphometry and directional brain connectivity during resting-state were analyzed. Analysis of variance (ANOVA) and 2-sample t tests were used to compare each pair of groups, using sex, age, education level, structural atrophy, and/or HAMD, unified PD rating scale (UPDRS) as covariates.In contrast to NC, DPD showed significant gray matter (GM) volume abnormalities in some mid-line limbic regions including dorsomedial prefrontal cortex and precuneus, and sub-cortical regions including caudate and cerebellum. Relative to NC and MDD, both DPD and NDPD showed significantly increased directional connectivity from bilateral anterior insula and posterior orbitofrontal cortices to left inferior temporal cortex. As compared with NC, MDD and NDPD, alterations of directional connectivity in DPD were specifically observed in the pathway from bilateral anterior insula and posterior orbitofrontal cortices to right basal ganglia.Resting state directional connectivity alterations were observed between emotion network and motor network in DPD patients after controlling for age, sex, structural atrophy. Given that these alterations are unique to DPD, it may provide a potential differential biomarker for distinguishing DPD from NC, NDPD, and MDD.

  7. Hidden Sylvatic Foci of the Main Vector of Chagas Disease Triatoma infestans: Threats to the Vector Elimination Campaign?

    PubMed Central

    Schachter-Broide, Judith; Dujardin, Jean-Pierre; Dotson, Ellen M.; Kitron, Uriel; Gürtler, Ricardo E.

    2011-01-01

    Background Establishing the sources of reinfestation after residual insecticide spraying is crucial for vector elimination programs. Triatoma infestans, traditionally considered to be limited to domestic or peridomestic (abbreviated as D/PD) habitats throughout most of its range, is the target of an elimination program that has achieved limited success in the Gran Chaco region in South America. Methodology/Principal Findings During a two-year period we conducted semi-annual searches for triatomine bugs in every D/PD site and surrounding sylvatic habitats after full-coverage spraying of pyrethroid insecticides of all houses in a well-defined rural area in northwestern Argentina. We found six low-density sylvatic foci with 24 T. infestans in fallen or standing trees located 110–2,300 m from the nearest house or infested D/PD site detected after insecticide spraying, when house infestations were rare. Analysis of two mitochondrial gene fragments of 20 sylvatic specimens confirmed their species identity as T. infestans and showed that their composite haplotypes were the same as or closely related to D/PD haplotypes. Population studies with 10 polymorphic microsatellite loci and wing geometric morphometry consistently indicated the occurrence of unrestricted gene flow between local D/PD and sylvatic populations. Mitochondrial DNA and microsatellite sibship analyses in the most abundant sylvatic colony revealed descendents from five different females. Spatial analysis showed a significant association between two sylvatic foci and the nearest D/PD bug population found before insecticide spraying. Conclusions Our study shows that, despite of its high degree of domesticity, T. infestans has sylvatic colonies with normal chromatic characters (not melanic morphs) highly connected to D/PD conspecifics in the Argentinean Chaco. Sylvatic habitats may provide a transient or permanent refuge after control interventions, and function as sources for D/PD reinfestation. The

  8. Underlying manifestations of developmental phonological disorders in French-speaking pre-schoolers.

    PubMed

    Brosseau-Lapré, Françoise; Rvachew, Susan

    2016-11-17

    This study examined the psycholinguistic profiles of Quebec French-speaking children with developmental phonological disorders (DPD). The purpose was to determine whether the endophenotypes that have been identified in English-speaking children with DPD are similarly associated with speech impairment in French-speaking children. Seventy-two children with DPD and ten children with normally developing speech, aged four to six years, received a comprehensive assessment battery that included measures at the phenotype level (i.e. measures of overt speech production skills) and endophenotype level (i.e. measures of potential underlying core deficits such as phonological processing or oral motor impairments). The majority of the children with DPD presented with a psycholinguistic profile indicative of difficulties with phonological processing. Phonological processing skills also explained unique variance in speech production accuracy, indicating that French-speaking children with DPD, who produce different surface speech errors than English-speaking children with DPD, are nonetheless very similar with regards to their underlying psycholinguistic profile.

  9. Shock simulations of a single-site coarse-grain RDX model using the dissipative particle dynamics method with reactivity

    NASA Astrophysics Data System (ADS)

    Sellers, Michael S.; Lísal, Martin; Schweigert, Igor; Larentzos, James P.; Brennan, John K.

    2017-01-01

    In discrete particle simulations, when an atomistic model is coarse-grained, a tradeoff is made: a boost in computational speed for a reduction in accuracy. The Dissipative Particle Dynamics (DPD) methods help to recover lost accuracy of the viscous and thermal properties, while giving back a relatively small amount of computational speed. Since its initial development for polymers, one of the most notable extensions of DPD has been the introduction of chemical reactivity, called DPD-RX. In 2007, Maillet, Soulard, and Stoltz introduced implicit chemical reactivity in DPD through the concept of particle reactors and simulated the decomposition of liquid nitromethane. We present an extended and generalized version of the DPD-RX method, and have applied it to solid hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Demonstration simulations of reacting RDX are performed under shock conditions using a recently developed single-site coarse-grain model and a reduced RDX decomposition mechanism. A description of the methods used to simulate RDX and its transition to hot product gases within DPD-RX is presented. Additionally, we discuss several examples of the effect of shock speed and microstructure on the corresponding material chemistry.

  10. Genetic and environmental contributions to the co-occurrence of depressive personality disorder and DSM-IV personality disorders.

    PubMed

    Ørstavik, Ragnhild E; Kendler, Kenneth S; Røysamb, Espen; Czajkowski, Nikolai; Tambs, Kristian; Reichborn-Kjennerud, Ted

    2012-06-01

    One of the main controversies with regard to depressive personality disorder (DPD) concerns the co-occurrence with the established DSM-IV personality disorders (PDs). The main aim of this study was to examine to what extent DPD and the DSM-IV PDs share genetic and environmental risk factors, using multivariate twin modeling. The DSM-IV Structured Interview for Personality was applied to 2,794 young adult twins. Paranoid PD from Cluster A, borderline PD from Cluster B, and all three PDs from Cluster C were independently and significantly associated with DPD in multiple regression analysis. The genetic correlations between DPD and the other PDs were strong (.53-.83), while the environmental correlations were moderate (.36-.40). Close to 50% of the total variance in DPD was disorder specific. However, only 5% was due to disorder-specific genetic factors, indicating that a substantial part of the genetic vulnerability to DPD also increases the vulnerability to other PDs.

  11. Implicit Self-Esteem in Borderline Personality and Depersonalization Disorder

    PubMed Central

    Hedrick, Alexis N.; Berlin, Heather A.

    2012-01-01

    Self-perception is disrupted in people with borderline personality disorder (BPD) and depersonalization disorder (DPD), fluctuating with sudden shifts in affect in BPD and experienced as detached in DPD. Measures of implicit self-esteem (ISE), free from conscious control and presentation biases, may highlight how such disruptions of self-concept differentially affect these two populations on an unconscious level. We examined ISE using the Implicit Association Test, along with measures of emotion, behavior, and temperament, in BPD (n = 18), DPD (n = 18), and healthy control (n = 35) participants. DPD participants had significantly higher ISE and were more harm avoidant than BPD and control participants, while BPD participants had more “frontal” behaviors and impulsivity and less self-directedness and cooperativeness than DPD and control participants. Thus, while BPD and DPD commonly overlap in terms of dissociative symptoms and emotional irregularities, differences in self-esteem, behavior, and temperament can help identify where they diverge in terms of their cognition, behavior, and ultimately underlying neurobiology. PMID:22493585

  12. Probing autoinducer-2 based quorum sensing: the biological consequences of molecules unable to traverse equilibrium states.

    PubMed

    Tsuchikama, Kyoji; Lowery, Colin A; Janda, Kim D

    2011-09-02

    Bacteria have developed a cell-to-cell communication system, termed quorum sensing (QS), which allows for the population-dependent coordination of their behavior via the exchange of chemical signals. Autoinducer-2 (AI-2), a class of QS signals derived from 4,5-dihydroxy-2,3-pentandione (DPD), has been revealed as a universal signaling molecule in a variety of bacterial species. In spite of considerable interest, the study of putative AI-2 based QS systems remains a challenging topic in part due to the rapid interconversion between the linear and cyclic forms of DPD. Herein, we report the design and development of efficient syntheses of carbocyclic analogues of DPD, which are locked in the cyclic form. The synthetic analogues were evaluated for the modulation of AI-2-based QS in Vibrio harveyi and Salmonella typhimurium. No agonists were uncovered in either V. harveyi or S. typhimurium assay, whereas weak to moderate antagonists were found against V. harveyi. On the basis of NMR analyses and DFT calculations, the heterocyclic oxygen atom within DPD appears necessary to promote hydration at the C3 position of cyclic DPD to afford the active tetrahydroxy species. These results also shed light on the interaction between the heterocyclic oxygen atom and receptor proteins as well as the importance of the linear form and dynamic equilibrium of DPD as crucial requirements for activation of AI-2 based QS circuits.

  13. Construction of dissipative particle dynamics models for complex fluids via the Mori-Zwanzig formulation.

    PubMed

    Li, Zhen; Bian, Xin; Caswell, Bruce; Karniadakis, George Em

    2014-11-21

    We present a bottom-up coarse-graining procedure to construct mesoscopic force fields directly from microscopic dynamics. By grouping many bonded atoms in the molecular dynamics (MD) system into a single cluster, we compute both the conservative and non-conservative interactions between neighboring clusters. In particular, we perform MD simulations of polymer melts to provide microscopic trajectories for evaluating coarse-grained (CG) interactions. Subsequently, dissipative particle dynamics (DPD) is considered as the effective dynamics resulting from the Mori-Zwanzig (MZ) projection of the underlying atomistic dynamics. The forces between finite-size clusters have, in general, both radial and transverse components and hence we employ four different DPD models to account differently for such interactions. Quantitative comparisons between these DPD models indicate that the DPD models with MZ-guided force fields yield much better static and dynamics properties, which are consistent with the underlying MD system, compared to standard DPD with empirical formulae. When the rotational motion of the particle is properly taken into account, the entire velocity autocorrelation function of the MD system as well as the pair correlation function can be accurately reproduced by the MD-informed DPD model. Since this coarse-graining procedure is performed on an unconstrained MD system, our framework is general and can be used in other soft matter systems in which the clusters can be faithfully defined as CG particles.

  14. Screenwriting: A Strategy for the Improvement of Writing Instructional Practices (La escritura de guiones: una estrategia para mejorar las prácticas instruccionales de escritura)

    ERIC Educational Resources Information Center

    Amado, Hernán

    2010-01-01

    This article presents a pedagogical experience that addresses the use of an instructional strategy called screenwriting aimed at improving the teaching of writing in an educational context. This pedagogical intervention took place in a private English language school, where three adult students willingly participated to create their own short…

  15. Biblioteca Virtual de Salud Enfermería Regional: Trayectoria de Construcción, Fuentes de Información, Estrategias y Próximos Pasos.

    PubMed Central

    Lana, Francisco C. F.; Malvárez, Silvina

    2012-01-01

    Resumen La BVS Enfermeria constituye un nuevo paradigma en enfermería una vez que o modelo representa una expansión de la cooperación técnica y ha como objetivos centrales promover la ampliación del acceso la información sobre enfermería la través del acceso universal equitativo y construir un patrimonio informacional en enfermería, ayudando la mejorar la formación y práctica de enfermería a actuar con compromiso ético-social en el área de educación, investigación y atención a la salud. Como resultado del proceso de sensibilización, verifica-se la construcción de Bibliotecas Virtuales de Enfermería en varios países (Brasil, Argentina, Bolívia y Uruguay). La expectativa es que las BVS’s nacionais convergen a un gran portal que se está construyendo en una colaboración con BIREME/OPS/OMS, de la Asesoría Regional de Enfermería de la OPS-Washington y de Ministerio de Salud del Brasil, así como instituciones líderes en la producción del conocimiento en enfermería Iberoamérica. PMID:24199093

  16. Training in Metacognitive Strategies for Students' Vocabulary Improvement by Using Learning Journals (Entrenamiento de estrategias metacognitivas para mejorar vocabulario a través de diarios de aprendizaje)

    ERIC Educational Resources Information Center

    Diaz, Itala

    2015-01-01

    This study examined the effects of metacognitive strategies to help beginning young learners with difficulties increasing and retaining vocabulary. This was a qualitative study in which participants first went through metacognitive strategy instruction to provide awareness of learning strategies. Following this instruction, students underwent a…

  17. Foreign Language Learning: Strategies in the Context of STEM Education (Estrategias de Aprendizaje de Lenguas Extranjeras en el Contexto de la Educación STEM)

    ERIC Educational Resources Information Center

    Han, Turgay

    2015-01-01

    This study aims at providing an insightful evaluation of the EFL strategies used by first-year STEM (science, technology, engineering, and mathematics) students, and their perceptions of their own use of strategies. The 147 participants were undergraduate level, first-year engineering students at a state university in Turkey. Their ages ranged…

  18. Investigacion Educativa: Areas - Politicas - Estrategias y Proyectos del ICOLPE, 2 (Educational Research: Topics, Policies, Strategies, and Projects of the Colombian Institute of Pedagogy, 2),

    ERIC Educational Resources Information Center

    Ministerio de Educacion Nacional, Bogota (Colombia). Instituto Colombiano de Pedagogia.

    This booklet defines and establishes guidelines for educational research in Colombia. Sections describe basic philosophy and objectives, types of research, policies for educational investigation, governmental role, and principle areas for educational research. A listing of current and proposed research projects is provided. The final section…

  19. Reading Strategies to Develop Higher Thinking Skills for Reading Comprehension (Estrategias de lectura para el desarrollo de habilidades de pensamiento para la comprensión de lectura)

    ERIC Educational Resources Information Center

    Echeverri Acosta, Luz Marina; McNulty Ferri, Maria

    2010-01-01

    This paper reports an action research project which examined the foreign language reading comprehension of public school eighth graders who experienced a directed reading-thinking approach with strategies for comprehension and application. The strategies used were prediction, prior knowledge, graphic organizers, and questions. Data analyzed…

  20. Building up Autonomy through Reading Strategies (Formación en autonomía a través de estrategias de lectura)

    ERIC Educational Resources Information Center

    Izquierdo Castillo, Alexander; Jiménez Bonilla, Sonia

    2014-01-01

    This article reports on an action research project conducted with six ninth grade students in a rural public school in Colombia. The purpose of the study was to determine how the implementation of three reading strategies (skimming, scanning, and making predictions), when reading topics selected by learners, helps them to improve their reading…

  1. Evangelizacion Indigena en Cuba (1512-1550): Estrategia y Razones de su Fracaso (Evangelization of Indigenous People in Cuba (1512-1550): Strategies and Reasons for its Failure).

    ERIC Educational Resources Information Center

    Puentes, Roberto Valdes; Reyes, Francisco Barroso

    2000-01-01

    Presents the different moments and contents of the strategies of the evangelization process practiced by the Spanish during the conquest and colonization of Cuba, as well as possible reasons for its failure. States that the Indians were enslaved and directed through evangelism toward acculturation. (BT)

  2. La Red Regional Replad: Una Estrategia Innovadora para la Capacitacion de Administradores Educacionales (The Regional Network Replad: An Innovative Strategy for the Training and Preparation of Educational Administrators).

    ERIC Educational Resources Information Center

    Jimenez Espinoza, Jorge

    This document presents an overview, analysis, and historical assessment of the Major Project for Education in Latin America and the Caribbean. Conferences, regional meetings, and outcomes from the inception of the project in 1979 are described. This project stresses the establishment of a regional network for exchange of information, experiences,…

  3. Evangelizacion Indigena en Cuba (1512-1550): Estrategia y Razones de su Fracaso (Evangelization of Indigenous People in Cuba (1512-1550): Strategies and Reasons for its Failure).

    ERIC Educational Resources Information Center

    Puentes, Roberto Valdes; Reyes, Francisco Barroso

    2000-01-01

    Presents the different moments and contents of the strategies of the evangelization process practiced by the Spanish during the conquest and colonization of Cuba, as well as possible reasons for its failure. States that the Indians were enslaved and directed through evangelism toward acculturation. (BT)

  4. La Red Regional Replad: Una Estrategia Innovadora para la Capacitacion de Administradores Educacionales (The Regional Network Replad: An Innovative Strategy for the Training and Preparation of Educational Administrators).

    ERIC Educational Resources Information Center

    Jimenez Espinoza, Jorge

    This document presents an overview, analysis, and historical assessment of the Major Project for Education in Latin America and the Caribbean. Conferences, regional meetings, and outcomes from the inception of the project in 1979 are described. This project stresses the establishment of a regional network for exchange of information, experiences,…

  5. Deoxypyridinoline in the Urine of Rats with Unloaded Hindlimbs

    NASA Technical Reports Server (NTRS)

    Arnaud, Sara B.; Navidi, M.; Wren, J.; Holton, Emily M. (Technical Monitor)

    1997-01-01

    The urinary excretion of deoxypyridinoline (U-Dpd), a nonreducible collagen crosslink in bone released by osteoclastic activity, is thought to be an accurate marker of bone resorption. The role of increased resorption in the osteopenia of a space flight model which unloads the hindlimbs by suspending the tail is controversial. To assess skeletal resorption in the model we measured U-Dpd (Pyrilinks-D, Metro Biosystems, Inc.) in serial 24 hour urine specimens collected from 250 a (Y) and 450 a (M) male rats with unloaded hindlimbs for four weeks. Both groups of rats were fed AIN76 diets with calcium restricted to 0.2% in Y and to 0.1 % in M. Blood was obtained after 28 days for parathyroid hormone (PTH), 1,25-dihydroxyvitamin D (1,25-D) and alkaline phosphatase (Alkptase). Basal U-Dpd was higher and more variable in Y than M (475+/-200 vs 67+/-9, nM/mM creatinine, p<.001). Repeated measures ANOVA in Y revealed decreases in U-Dpd, 36% in control (C) and 24% in unloaded (S) rats (p<.005). There was a nadir in YS on the 14th day not observed in YC (p<.05). U-Dpd in MC showed no change, but increased in MS by the 14th day and remained elevated. At the end of the experiment, body weights in both Y and M were less in S than C (337+/-16 vs 306+/-12g and 485+/-10 vs 461+/-6g, p=.002). Bill was inversely related to U-Dpd only in M (r=0.699, p=.024). PTH, similar in C and S in Y (52+/-15 vs 42+/-7pg/ml, NS) and M (68+/-13 vs 61+/-12, NS), was unrelated to U-Dpd. 1,25-D tended toward higher values in YC than YS (197+/-103 vs 119+/-30, NS) and correlated with U-Dpd (0.773, p=.015). Alkptase, 1.3 times higher in Y than M, was similar in C and S at the end of unloading. These findings indicate that bone resorption, as reflected by U-Dpd, is suppressed in young and stimulated in mature rats exposed to a space flight model. U-Dpd reflects reduced growth from the diet change in young control and experimental rats and loss of Bill in mature animals exposed to the space flight model, 2

  6. Deoxypyridinoline in the Urine of Rats with Unloaded Hindlimbs

    NASA Technical Reports Server (NTRS)

    Arnaud, Sara B.; Navidi, M.; Wren, J.; Holton, Emily M. (Technical Monitor)

    1997-01-01

    The urinary excretion of deoxypyridinoline (U-Dpd), a nonreducible collagen crosslink in bone released by osteoclastic activity, is thought to be an accurate marker of bone resorption. The role of increased resorption in the osteopenia of a space flight model which unloads the hindlimbs by suspending the tail is controversial. To assess skeletal resorption in the model we measured U-Dpd (Pyrilinks-D, Metro Biosystems, Inc.) in serial 24 hour urine specimens collected from 250 a (Y) and 450 a (M) male rats with unloaded hindlimbs for four weeks. Both groups of rats were fed AIN76 diets with calcium restricted to 0.2% in Y and to 0.1 % in M. Blood was obtained after 28 days for parathyroid hormone (PTH), 1,25-dihydroxyvitamin D (1,25-D) and alkaline phosphatase (Alkptase). Basal U-Dpd was higher and more variable in Y than M (475+/-200 vs 67+/-9, nM/mM creatinine, p<.001). Repeated measures ANOVA in Y revealed decreases in U-Dpd, 36% in control (C) and 24% in unloaded (S) rats (p<.005). There was a nadir in YS on the 14th day not observed in YC (p<.05). U-Dpd in MC showed no change, but increased in MS by the 14th day and remained elevated. At the end of the experiment, body weights in both Y and M were less in S than C (337+/-16 vs 306+/-12g and 485+/-10 vs 461+/-6g, p=.002). Bill was inversely related to U-Dpd only in M (r=0.699, p=.024). PTH, similar in C and S in Y (52+/-15 vs 42+/-7pg/ml, NS) and M (68+/-13 vs 61+/-12, NS), was unrelated to U-Dpd. 1,25-D tended toward higher values in YC than YS (197+/-103 vs 119+/-30, NS) and correlated with U-Dpd (0.773, p=.015). Alkptase, 1.3 times higher in Y than M, was similar in C and S at the end of unloading. These findings indicate that bone resorption, as reflected by U-Dpd, is suppressed in young and stimulated in mature rats exposed to a space flight model. U-Dpd reflects reduced growth from the diet change in young control and experimental rats and loss of Bill in mature animals exposed to the space flight model, 2

  7. Computing the non-Markovian coarse-grained interactions derived from the Mori-Zwanzig formalism in molecular systems: Application to polymer melts.

    PubMed

    Li, Zhen; Lee, Hee Sun; Darve, Eric; Karniadakis, George Em

    2017-01-07

    Memory effects are often introduced during coarse-graining of a complex dynamical system. In particular, a generalized Langevin equation (GLE) for the coarse-grained (CG) system arises in the context of Mori-Zwanzig formalism. Upon a pairwise decomposition, GLE can be reformulated into its pairwise version, i.e., non-Markovian dissipative particle dynamics (DPD). GLE models the dynamics of a single coarse particle, while DPD considers the dynamics of many interacting CG particles, with both CG systems governed by non-Markovian interactions. We compare two different methods for the practical implementation of the non-Markovian interactions in GLE and DPD systems. More specifically, a direct evaluation of the non-Markovian (NM) terms is performed in LE-NM and DPD-NM models, which requires the storage of historical information that significantly increases computational complexity. Alternatively, we use a few auxiliary variables in LE-AUX and DPD-AUX models to replace the non-Markovian dynamics with a Markovian dynamics in a higher dimensional space, leading to a much reduced memory footprint and computational cost. In our numerical benchmarks, the GLE and non-Markovian DPD models are constructed from molecular dynamics (MD) simulations of star-polymer melts. Results show that a Markovian dynamics with auxiliary variables successfully generates equivalent non-Markovian dynamics consistent with the reference MD system, while maintaining a tractable computational cost. Also, transient subdiffusion of the star-polymers observed in the MD system can be reproduced by the coarse-grained models. The non-interacting particle models, LE-NM/AUX, are computationally much cheaper than the interacting particle models, DPD-NM/AUX. However, the pairwise models with momentum conservation are more appropriate for correctly reproducing the long-time hydrodynamics characterised by an algebraic decay in the velocity autocorrelation function.

  8. Computing the non-Markovian coarse-grained interactions derived from the Mori-Zwanzig formalism in molecular systems: Application to polymer melts

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Lee, Hee Sun; Darve, Eric; Karniadakis, George Em

    2017-01-01

    Memory effects are often introduced during coarse-graining of a complex dynamical system. In particular, a generalized Langevin equation (GLE) for the coarse-grained (CG) system arises in the context of Mori-Zwanzig formalism. Upon a pairwise decomposition, GLE can be reformulated into its pairwise version, i.e., non-Markovian dissipative particle dynamics (DPD). GLE models the dynamics of a single coarse particle, while DPD considers the dynamics of many interacting CG particles, with both CG systems governed by non-Markovian interactions. We compare two different methods for the practical implementation of the non-Markovian interactions in GLE and DPD systems. More specifically, a direct evaluation of the non-Markovian (NM) terms is performed in LE-NM and DPD-NM models, which requires the storage of historical information that significantly increases computational complexity. Alternatively, we use a few auxiliary variables in LE-AUX and DPD-AUX models to replace the non-Markovian dynamics with a Markovian dynamics in a higher dimensional space, leading to a much reduced memory footprint and computational cost. In our numerical benchmarks, the GLE and non-Markovian DPD models are constructed from molecular dynamics (MD) simulations of star-polymer melts. Results show that a Markovian dynamics with auxiliary variables successfully generates equivalent non-Markovian dynamics consistent with the reference MD system, while maintaining a tractable computational cost. Also, transient subdiffusion of the star-polymers observed in the MD system can be reproduced by the coarse-grained models. The non-interacting particle models, LE-NM/AUX, are computationally much cheaper than the interacting particle models, DPD-NM/AUX. However, the pairwise models with momentum conservation are more appropriate for correctly reproducing the long-time hydrodynamics characterised by an algebraic decay in the velocity autocorrelation function.

  9. Factors predicting the response to oral fluoropyrimidine drugs: a phase II trial on the individualization of postoperative adjuvant chemotherapy using oral fluorinated pyrimidines in stage III colorectal cancer treated by curative resection (ACT-01 Study).

    PubMed

    Mori, Takeo; Ohue, Masayuki; Takii, Yasumasa; Hashizume, Tadashi; Kato, Tomoyuki; Kotake, Kenjiro; Sato, Toshihiko; Tango, Toshiro

    2013-02-01

    We evaluated the predictive relevance of several biomarkers on the survival of patients with stage III colorectal cancer treated with adjuvant chemotherapy of oral fluoropyrimidines. This was a multicenter phase II trial on adult patients with histologically confirmed resected stage III (Dukes' C) colorectal cancer. Patients received oral doxifluridine (800 mg/m2/day) in 3 divided doses, or oral uracil/tegafur (UFT) (400 mg/m2/day) in 2 divided doses for 5 days, every 7 days for 12 months with a 5-year follow-up. Outcome measures were disease-free survival and tissue markers [thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD) protein levels and TP, DPD, thymidylate synthase (TS) and orotate phosphoribosyltransferase (OPRT) mRNA levels in tumor samples and TS tandem-repeat type in blood samples]. There was a significant association between the intratumoral TP/DPD enzyme ratio and disease-free survival when the model included the drug, the parameter and the interactions between them [hazard ratio (HR)=2.76; P=0.00469]. The 5-year disease-free survival rate was statistically significantly higher in patients with high TP/DPD ratios [median ≥2.63: 71.9%; 95% confidence interval (CI) 61.4-80.0] compared to patients with low TP/DPD ratios (<2.63: 57.0%; 95% CI 46.3-66.3) (log-rank P=0.0277) following adjuvant therapy with oral fluoropyrimidines. No significant association was observed between the intratumoral TP/DPD enzyme ratio (cut-off value 2.0) and the disease-free survival rate in the doxifluridine group; primary endpoint (log-rank P=0.6850). The magnitude of the intratumoral TP/DPD enzyme ratio may be a potential indicator for the individualization of postoperative adjuvant chemotherapy with oral fluoropyrimidines for stage III colorectal cancer.

  10. New insights in dihydropyrimidine dehydrogenase deficiency: a pivotal role for beta-aminoisobutyric acid?

    PubMed

    Van Kuilenburg, André B P; Stroomer, Alida E M; Van Lenthe, Henk; Abeling, Nico G G M; Van Gennip, Albert H

    2004-04-01

    DPD (dihydropyrimidine dehydrogenase) constitutes the first step of the pyrimidine degradation pathway, in which the pyrimidine bases uracil and thymine are catabolized to beta-alanine and the R-enantiomer of beta-AIB (beta-aminoisobutyric acid) respectively. The S-enantiomer of beta-AIB is predominantly derived from the catabolism of valine. It has been suggested that an altered homoeostasis of beta-alanine underlies some of the clinical abnormalities encountered in patients with a DPD deficiency. In the present study, we demonstrated that only a slightly decreased concentration of beta-alanine was present in the urine and plasma, whereas normal levels of beta-alanine were present in the cerebrospinal fluid of patients with a DPD deficiency. Therefore the metabolism of beta-alanine-containing peptides, such as carnosine, may be an important factor involved in the homoeostasis of beta-alanine in patients with DPD deficiency. The mean concentration of beta-AIB was approx. 2-3-fold lower in cerebrospinal fluid and urine of patients with a DPD deficiency, when compared with controls. In contrast, strongly decreased levels (10-fold) of beta-AIB were present in the plasma of DPD patients. Our results demonstrate that, under pathological conditions, the catabolism of valine can result in the production of significant amounts of beta-AIB. Furthermore, the observation that the R-enantiomer of beta-AIB is abundantly present in the urine of DPD patients suggests that significant cross-over exists between the thymine and valine catabolic pathways.

  11. Observação do abrilhantamento de limbo solar e de estruturas filamentares em 48 ghz utilizando a técnica de regularização adaptativa

    NASA Astrophysics Data System (ADS)

    Machado, W. R. S.; Mascarenhas, N.; Costa, J. E. R.; Silva, A. V. R.

    2003-08-01

    O radiotelescópio do Itapetinga tem sido utilizado em campanhas de observações de explosões solares gerando um grande número de mapas diários em 48 GHz como sub-produto destas observações. A resolução espacial do telescópio de 14m do Itapetinga nesta freqüência é de aproximadamente dois minutos de arco. Estruturas de interesse para análise da atmosfera solar quiescente tais como os filamentos e o anel de abrilhantamento do limbo são de dimensão angular moderada da ordem ou ligeiramente menores que a resolução do telescópio. É conhecido que a convolução da função de espalhamento do telescópio, PSF (padrão de ganho do feixe) borra as estruturas de dimensão angular abaixo do HPBW (largura a meia potência do feixe) e portanto é comum a busca por técnicas de restauração que eliminem pelo menos em parte este borramento. Estudamos a restauração destas radioimagens usando a técnica de regularização adaptativa e os resultados ressaltam estas estruturas espaciais de pequeno contraste. O algoritmo da regularização adaptativa faz uso de k imagens, chamadas protótipos, obtidas através da variação de parâmetros de um filtro de regularização. Para controle da qualidade da restauração utilizamos uma imagem de alta resolução espacial obtida na linha H-a e a PSF do Itapetinga para borrá-la. Pequenos desvios, entre a PSF utilizada para o borramento e a PSF utilizada na restauração, produziram alguns desvios notáveis na imagem restaurada porém a adição de ruído nas simulações de restauração foram mais influentes no cálculo da rugosidade da imagem e portanto mais limitante para a restauração. Apresentamos como nosso primeiro resultado uma imagem em 48 GHz com a presença clara do abrilhantamento de limbo que não estava evidente na imagem original e traços de estruturas filamentares, porém ainda sem grande evidência.

  12. Gas Diffusivity And Air Permeability In Sandy Soils: Effect Of Particle Size, Compaction And Sample Scale

    NASA Astrophysics Data System (ADS)

    Hamamoto, S.; Kawamoto, K.; Moldrup, P.; Komatsu, T.

    2007-12-01

    The transport and fate of gases in soils is mainly governed by gas diffusion and advection. The gas diffusivity (Dp/D0) is the transport parameter for the gas diffusion due to gas concentration gradient, while the air permeability (ka) is the transport parameter for advective gas transport due to soil-air pressure gradient. Hence, those gas transport parameters play a crucial role in simulating transport of gaseous contaminants such as volatile organic chemicals and in quantifying emission and exchange of greenhouse gases from/at the soil- atmosphere interface. In this study, we measured Dp/D0 and ka for total of six sandy soils and examined the effects of soil physical properties such as particle size, soil compaction, and sample scale on the gas transport parameters. Toyoura sand (0.106-0.50 mm) and Narita sands with three different particle size fractions (0.106-0.25, 0.25- 0.425, 0.425-0.85 mm) were used as experimental materials for the measurements of Dp/D0 and ka. The sand materials were repacked with given bulk densities into small-scale cores of 100 cm3 (for all materials) and large-scale cores of 2120 cm3 (only for Toyoura sand) at given water contents. In addition to the measurements, Dp/D0 and ka of Oso Flaco fine sand and Oakley sand from literature were also analyzed in this study. For all sand materials, we observed the threshold soil-air content (ɛth) below which Dp/D0 and ka are negligible, and measured Dp/D0 and ka increased linearly with increasing air-filled porosity (ɛ) from ɛth to soil total porosity (Φ). At high ɛ, sand materials with larger average particle diameter (APD) gave higher Dp/D0 and ka than those with smaller APD sands at a given ɛ due to the existence of rapid air flow through the highly continuous large pores. At low ɛ near the ɛth however, the measured Dp/D0 for large APD sands were lower than those for small APD sands. The measurements for Narita sand fractions with different bulk densities indicated that soil

  13. A comparison of methods for measuring serum and urinary markers of bone metabolism in cats.

    PubMed

    DeLaurier, A; Jackson, B; Pfeiffer, D; Ingham, K; Horton, M A; Price, J S

    2004-08-01

    Biochemical markers of bone cell activity have recently been shown to be useful for monitoring skeletal health in domestic animals, including dogs and horses. The aim of this study was to evaluate a number of biochemical assays, originally developed for use in humans, for their ability to measure indicators of bone cell activity in serum and urine of normal cats over a range of ages. Bone alkaline phosphatase (BAP), a marker of bone formation, was measured in serum using wheatgerm lectin precipitation (WGL) and by ELISA. The curve derived from serial dilution of feline serum was parallel with the ELISA standard curve, indicating species cross-reactivity, and there was a significant relationship between assays (rs = 0.97, P < 0.001). Deoxypyridinoline (DPD), a marker of bone resorption, was measured in its total form in urine by HPLC and ELISA, and in its free form in serum and urine by ELISA. The dilution curve for free DPD in urine showed parallelism with the assay standard curve; however, the curves for total DPD in urine and serum did not. A significant relationship was established between total urinary DPD (HPLC) with total serum DPD (rs = 0.69, P < 0.001), and with free urinary DPD (rs = 0.95, P < 0.001) concentrations. Carboxy-terminal telopeptide of type I collagen (CTX) concentration, another marker of bone resorption, was measured in serum and urine by ELISA, and there was a significant relationship between assays (rs = 0.82, P < 0.001). CTX could not be measured reliably using an auto-analysis method. A significant relationship was established between total urinary DPD (HPLC) with serum CTX (rs = 0.59, P < 0.05), and urinary CTX (rs = 0.65, P < 0.001) concentrations. BAP (ELISA and WGL), total urinary DPD (HPLC), urinary CTX (ELISA), and serum CTX (ELISA) concentrations were significantly inversely correlated with age (rs = -0.66, -0.88, -0.61, -0.70, and -0.51, P < 0.05 respectively). Cats under two years of age had significantly higher BAP, total

  14. Echo contrast-enhanced three-dimensional power Doppler of intracranial arteries.

    PubMed

    Postert, T; Braun, B; Pfundtner, N; Sprengelmeyer, R; Meves, S; Przuntek, H; Büttner, T

    1998-09-01

    The purpose of this study was to evaluate the potential of contrast-enhanced three-dimensional (3-D) power Doppler (CE3DPD) in the assessment of intracranial vascular structures, and to compare the results with unenhanced 3-D power Doppler (3DPD) and magnetic resonance angiography (MRA) findings. We insonated 25 patients without cerebrovascular diseases through the temporal bone window using 3DPD and CE3DPD; for comparison, 13 patients underwent MRA. Identification rates of vascular segments and of small branches of intracranial vessels were evaluated by two independent investigators blinded to MRA results. In 21 patients with adequate insonation conditions, CE3DPD significantly improved identification rates compared to 3DPD for the complete visualization of the P1 segment (80.9 vs. 19.0%, p < 0.005, P2 segment (80.9 vs. 42.8%, p < 0.05 and A1 segment (85.7 vs. 38.1%, p < 0.005). Furthermore, CE3DPD depicted, in significantly more examinations, branches of the middle (MCA) and posterior cerebral artery (PCA). Interobserver agreement was higher than 95% for the main intracranial segments and branches of the MCA, but relatively low (80.1-85.7%) for branches of the PCA. In comparison to CE3DPD, MRA identified only parieto-occipital branches of the PCA, temporal branches of the MCA, frontal branches of the anterior cerebral artery and the MCA bifurcation more frequently and accurately. In 4 patients with inadequate acoustic temporal bone windows, the application of a galactose-based microbubble suspension allowed clear 3-D visualization of almost all major intracranial vascular segments and some branches of the large arteries. In conclusion, CE3DPD is a more sensitive ultrasonic tool compared to unenhanced 3-D reconstructions. It makes 3-D ultrasound imaging of the basal cerebral circulation easier to perform and interpret, by providing an improved spatially oriented display of image position. As such, this method may increase operator diagnostic confidence level under

  15. Coarse-grained model of water diffusion and proton conductivity in hydrated polyelectrolyte membrane

    SciTech Connect

    Lee, Ming-Tsung; Vishnyakov, Aleksey; Neimark, Alexander V.

    2016-01-07

    Using dissipative particle dynamics (DPD), we simulate nanoscale segregation, water diffusion, and proton conductivity in hydrated sulfonated polystyrene (sPS). We employ a novel model [Lee et al. J. Chem. Theory Comput. 11(9), 4395-4403 (2015)] that incorporates protonation/deprotonation equilibria into DPD simulations. The polymer and water are modeled by coarse-grained beads interacting via short-range soft repulsion and smeared charge electrostatic potentials. The proton is introduced as a separate charged bead that forms dissociable Morse bonds with the base beads representing water and sulfonate anions. Morse bond formation and breakup artificially mimics the Grotthuss mechanism of proton hopping between the bases. The DPD model is parameterized by matching the proton mobility in bulk water, dissociation constant of benzenesulfonic acid, and liquid-liquid equilibrium of water-ethylbenzene solutions. The DPD simulations semi-quantitatively predict nanoscale segregation in the hydrated sPS into hydrophobic and hydrophilic subphases, water self-diffusion, and proton mobility. As the hydration level increases, the hydrophilic subphase exhibits a percolation transition from isolated water clusters to a 3D network. The analysis of hydrophilic subphase connectivity and water diffusion demonstrates the importance of the dynamic percolation effect of formation and breakup of temporary junctions between water clusters. The proposed DPD model qualitatively predicts the ratio of proton to water self-diffusion and its dependence on the hydration level that is in reasonable agreement with experiments.

  16. Dissipative particle dynamics simulation of dilute polymer solutions—Inertial effects and hydrodynamic interactions

    SciTech Connect

    Zhao, Tongyang; Wang, Xiaogong; Jiang, Lei; Larson, Ronald G.

    2014-07-01

    We examine the accuracy of dissipative particle dynamics (DPD) simulations of polymers in dilute solutions with hydrodynamic interaction (HI), at the theta point, modeled by setting the DPD conservative interaction between beads to zero. We compare the first normal-mode relaxation time extracted from the DPD simulations with theoretical predictions from a normal-mode analysis for theta chains. We characterize the influence of bead inertia within the coil by a ratio L{sub m}/R{sub g}, where L{sub m} is the ballistic distance over which bead inertia is lost, and R{sub g} is the radius of gyration of the polymer coil, while the HI strength per bead h* is determined by the ratio of bead hydrodynamic radius (r{sub H}) to the equilibrium spring length. We show how to adjust h* through the spring length and monomer mass, and how to optimize the accuracy of DPD for fixed h* by increasing the friction coefficient (γ ≥ 9) and by incorporating a nonlinear distance dependence into the frictional interaction. Even with this optimization, DPD simulations exhibit deviations of over 20% from the theoretical normal-mode predictions for high HI strength with h* ≥ 0.20, for chains with as many as 100 beads, which is a larger deviation than is found for Stochastic rotation dynamics simulations for similar chains lengths and values of h*.

  17. Distortion and flow of nematics simulated by dissipative particle dynamics.

    PubMed

    Zhao, Tongyang; Wang, Xiaogong

    2014-05-14

    In this study, we simulated distortion and flow of nematics by dissipative particle dynamics (DPD). The nematics were modeled by a binary mixture that contained rigid rods composed of DPD particles as mesogenic units and normal DPD particles as solvent. Elastic distortions were investigated by monitoring director orientation in space under influences of boundary anchoring and external fields. Static distortion demonstrated by the simulation is consistent with the prediction of Frank elastic theory. Spatial distortion profile of the director was examined to obtain static elastic constants. Rotational motions of the director under influence of the external field were simulated to understand the dynamic process. The rules revealed by the simulation are in a good agreement with those obtained from dynamical experiments and classical theories for nematics. Three Miesowicz viscosities were obtained by using external fields to hold the orientation of the rods in shear flows. The simulation showed that the Miesowicz viscosities have the order of ηc > ηa > ηb and the rotational viscosity γ1 is about two orders larger than the Miesowicz viscosity ηb. The DPD simulation correctly reproduced the non-monotonic concentration dependence of viscosity, which is a unique property of lyotropic nematic fluids. By comparing simulation results with classical theories for nematics and experiments, the DPD nematic fluids are proved to be a valid model to investigate the distortion and flow of lyotropic nematics.

  18. Incorporation of memory effects in coarse-grained modeling via the Mori-Zwanzig formalism.

    PubMed

    Li, Zhen; Bian, Xin; Li, Xiantao; Karniadakis, George Em

    2015-12-28

    The Mori-Zwanzig formalism for coarse-graining a complex dynamical system typically introduces memory effects. The Markovian assumption of delta-correlated fluctuating forces is often employed to simplify the formulation of coarse-grained (CG) models and numerical implementations. However, when the time scales of a system are not clearly separated, the memory effects become strong and the Markovian assumption becomes inaccurate. To this end, we incorporate memory effects into CG modeling by preserving non-Markovian interactions between CG variables, and the memory kernel is evaluated directly from microscopic dynamics. For a specific example, molecular dynamics (MD) simulations of star polymer melts are performed while the corresponding CG system is defined by grouping many bonded atoms into single clusters. Then, the effective interactions between CG clusters as well as the memory kernel are obtained from the MD simulations. The constructed CG force field with a memory kernel leads to a non-Markovian dissipative particle dynamics (NM-DPD). Quantitative comparisons between the CG models with Markovian and non-Markovian approximations indicate that including the memory effects using NM-DPD yields similar results as the Markovian-based DPD if the system has clear time scale separation. However, for systems with small separation of time scales, NM-DPD can reproduce correct short-time properties that are related to how the system responds to high-frequency disturbances, which cannot be captured by the Markovian-based DPD model.

  19. Symmetry boundary condition in dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Pal, Souvik; Lan, Chuanjin; Li, Zhen; Hirleman, E. Daniel; Ma, Yanbao

    2015-07-01

    Dissipative particle dynamics (DPD) is a coarse-grained particle method for modeling mesoscopic hydrodynamics. Most of the DPD simulations are carried out in 3D requiring remarkable computation time. For symmetric systems, this time can be reduced significantly by simulating only one half or one quarter of the systems. However, such simulations are not yet possible due to a lack of schemes to treat symmetric boundaries in DPD. In this study, we propose a numerical scheme for the implementation of the symmetric boundary condition (SBC) in both dissipative particle dynamics (DPD) and multibody dissipative particle dynamics (MDPD) using a combined ghost particles and specular reflection (CGPSR) method. We validate our scheme in four different configurations. The results demonstrate that our scheme can accurately reproduce the system properties, such as velocity, density and meniscus shapes of a full system with numerical simulations of a subsystem. Using a symmetric boundary condition for one half of the system, we demonstrate about 50% computation time saving in both DPD and MDPD. This approach for symmetric boundary treatment can be also applied to other coarse-grained particle methods such as Brownian and Langevin Dynamics to significantly reduce computation time.

  20. Incorporation of memory effects in coarse-grained modeling via the Mori-Zwanzig formalism

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Bian, Xin; Li, Xiantao; Karniadakis, George Em

    2015-12-01

    The Mori-Zwanzig formalism for coarse-graining a complex dynamical system typically introduces memory effects. The Markovian assumption of delta-correlated fluctuating forces is often employed to simplify the formulation of coarse-grained (CG) models and numerical implementations. However, when the time scales of a system are not clearly separated, the memory effects become strong and the Markovian assumption becomes inaccurate. To this end, we incorporate memory effects into CG modeling by preserving non-Markovian interactions between CG variables, and the memory kernel is evaluated directly from microscopic dynamics. For a specific example, molecular dynamics (MD) simulations of star polymer melts are performed while the corresponding CG system is defined by grouping many bonded atoms into single clusters. Then, the effective interactions between CG clusters as well as the memory kernel are obtained from the MD simulations. The constructed CG force field with a memory kernel leads to a non-Markovian dissipative particle dynamics (NM-DPD). Quantitative comparisons between the CG models with Markovian and non-Markovian approximations indicate that including the memory effects using NM-DPD yields similar results as the Markovian-based DPD if the system has clear time scale separation. However, for systems with small separation of time scales, NM-DPD can reproduce correct short-time properties that are related to how the system responds to high-frequency disturbances, which cannot be captured by the Markovian-based DPD model.

  1. Incorporation of memory effects in coarse-grained modeling via the Mori-Zwanzig formalism

    SciTech Connect

    Li, Zhen; Bian, Xin; Karniadakis, George Em; Li, Xiantao

    2015-12-28

    The Mori-Zwanzig formalism for coarse-graining a complex dynamical system typically introduces memory effects. The Markovian assumption of delta-correlated fluctuating forces is often employed to simplify the formulation of coarse-grained (CG) models and numerical implementations. However, when the time scales of a system are not clearly separated, the memory effects become strong and the Markovian assumption becomes inaccurate. To this end, we incorporate memory effects into CG modeling by preserving non-Markovian interactions between CG variables, and the memory kernel is evaluated directly from microscopic dynamics. For a specific example, molecular dynamics (MD) simulations of star polymer melts are performed while the corresponding CG system is defined by grouping many bonded atoms into single clusters. Then, the effective interactions between CG clusters as well as the memory kernel are obtained from the MD simulations. The constructed CG force field with a memory kernel leads to a non-Markovian dissipative particle dynamics (NM-DPD). Quantitative comparisons between the CG models with Markovian and non-Markovian approximations indicate that including the memory effects using NM-DPD yields similar results as the Markovian-based DPD if the system has clear time scale separation. However, for systems with small separation of time scales, NM-DPD can reproduce correct short-time properties that are related to how the system responds to high-frequency disturbances, which cannot be captured by the Markovian-based DPD model.

  2. A phase-field approach to no-slip boundary conditions in dissipative particle dynamics and other particle models for fluid flow in geometrically complex confined systems.

    PubMed

    Xu, Zhijie; Meakin, Paul

    2009-06-21

    Dissipative particle dynamics (DPD) is an effective mesoscopic particle model with a lower computational cost than molecular dynamics because of the soft potentials that it employs. However, the soft potential is not strong enough to prevent the DPD particles that are used to represent the fluid from penetrating solid boundaries represented by stationary DPD particles. A phase-field variable, phi(x,t), is used to indicate the phase at point x and time t, with a smooth transition from -1 (phase 1) to +1 (phase 2) across the interface. We describe an efficient implementation of no-slip boundary conditions in DPD models that combines solid-liquid particle-particle interactions with reflection at a sharp boundary located with subgrid scale accuracy using the phase field. This approach can be used for arbitrarily complex flow geometries and other similar particle models (such as smoothed particle hydrodynamics), and the validity of the model is demonstrated by DPD simulations of flow in confined systems with various geometries.

  3. Bottom-up derivation of conservative and dissipative interactions for coarse-grained molecular liquids with the conditional reversible work method

    SciTech Connect

    Deichmann, Gregor; Marcon, Valentina; Vegt, Nico F. A. van der

    2014-12-14

    Molecular simulations of soft matter systems have been performed in recent years using a variety of systematically coarse-grained models. With these models, structural or thermodynamic properties can be quite accurately represented while the prediction of dynamic properties remains difficult, especially for multi-component systems. In this work, we use constraint molecular dynamics simulations for calculating dissipative pair forces which are used together with conditional reversible work (CRW) conservative forces in dissipative particle dynamics (DPD) simulations. The combined CRW-DPD approach aims to extend the representability of CRW models to dynamic properties and uses a bottom-up approach. Dissipative pair forces are derived from fluctuations of the direct atomistic forces between mapped groups. The conservative CRW potential is obtained from a similar series of constraint dynamics simulations and represents the reversible work performed to couple the direct atomistic interactions between the mapped atom groups. Neopentane, tetrachloromethane, cyclohexane, and n-hexane have been considered as model systems. These molecular liquids are simulated with atomistic molecular dynamics, coarse-grained molecular dynamics, and DPD. We find that the CRW-DPD models reproduce the liquid structure and diffusive dynamics of the liquid systems in reasonable agreement with the atomistic models when using single-site mapping schemes with beads containing five or six heavy atoms. For a two-site representation of n-hexane (3 carbons per bead), time scale separation can no longer be assumed and the DPD approach consequently fails to reproduce the atomistic dynamics.

  4. Bottom-up derivation of conservative and dissipative interactions for coarse-grained molecular liquids with the conditional reversible work method.

    PubMed

    Deichmann, Gregor; Marcon, Valentina; van der Vegt, Nico F A

    2014-12-14

    Molecular simulations of soft matter systems have been performed in recent years using a variety of systematically coarse-grained models. With these models, structural or thermodynamic properties can be quite accurately represented while the prediction of dynamic properties remains difficult, especially for multi-component systems. In this work, we use constraint molecular dynamics simulations for calculating dissipative pair forces which are used together with conditional reversible work (CRW) conservative forces in dissipative particle dynamics (DPD) simulations. The combined CRW-DPD approach aims to extend the representability of CRW models to dynamic properties and uses a bottom-up approach. Dissipative pair forces are derived from fluctuations of the direct atomistic forces between mapped groups. The conservative CRW potential is obtained from a similar series of constraint dynamics simulations and represents the reversible work performed to couple the direct atomistic interactions between the mapped atom groups. Neopentane, tetrachloromethane, cyclohexane, and n-hexane have been considered as model systems. These molecular liquids are simulated with atomistic molecular dynamics, coarse-grained molecular dynamics, and DPD. We find that the CRW-DPD models reproduce the liquid structure and diffusive dynamics of the liquid systems in reasonable agreement with the atomistic models when using single-site mapping schemes with beads containing five or six heavy atoms. For a two-site representation of n-hexane (3 carbons per bead), time scale separation can no longer be assumed and the DPD approach consequently fails to reproduce the atomistic dynamics.

  5. Conditional reasoning in Asperger's syndrome and depersonalization disorder.

    PubMed

    Lawrence, Emma Jane; Dumigan, Rachael; Schoenberg, Poppy; Mauricio, Sierra; Murphy, Declan G; David, Anthony S

    2012-09-01

    Conditional reasoning premises can be systematically manipulated to elicit specific response patterns. This is useful for investigating the reasoning style of people who report clinical symptoms. We administered a standardized conditional reasoning task to 16 participants with a diagnosis of Asperger's syndrome (AS), 16 participants with a diagnosis of depersonalization disorder (DPD), and 32 intelligence-quotient-matched controls. Premises were manipulated for a) context, with some being embedded within extra statements, and b) content, neutral or emotional. Both the AS and DPD participants were less likely to incorporate exceptions to the given premises than the controls, indicating difficulties with mental flexibility, although this effect was less marked in the DPD group. It seems the AS participants were also less influenced than the controls by statements that highlight possible alternative consequences. However, this effect was less robust than that observed with statements detailing exceptions, suggesting it may be because of general problems with executive function rather than difficulties in processing contextual information. We did not observe the expected difference between the DPD participants and the controls when reasoning with emotional premises. Overall, these data suggest that the DPD and AS participants have distinct reasoning styles, which may be of use for interventions based on cognitive change.

  6. The roles of dominos and nonsimultaneous chains in kidney paired donation.

    PubMed

    Gentry, S E; Montgomery, R A; Swihart, B J; Segev, D L

    2009-06-01

    Efforts to expand kidney paired donation have included matching nondirected donors (NDDs) to incompatible pairs. In domino paired donation (DPD), an NDD gives to the recipient of an incompatible pair, beginning a string of simultaneous transplants that ends with a living donor giving to a recipient on the deceased donor waitlist. Recently, nonsimultaneous extended altruistic donor (NEAD) chains were introduced. In a NEAD chain, the last donor of the string of transplants initiated by an NDD is reserved to donate at a later time. Our aim was to project the impact of each of these strategies over 2 years of operation for paired donation programs that also allocate a given number of NDDs. Each NDD facilitated an average of 1.99 transplants using DPD versus 1.90 transplants using NEAD chains (p = 0.3), or 1.0 transplants donating directly to the waitlist (p < 0.001). NEAD chains did not yield more transplants compared with simultaneous DPD. Both DPD and NEAD chains relax reciprocality requirements and rebalance the blood-type distribution of donors. Because traditional paired donation will leave many incompatible pairs unmatched, novel approaches like DPD and NEAD chains must be explored if paired donation programs are to help a greater number of people.

  7. Coarse-grained model of water diffusion and proton conductivity in hydrated polyelectrolyte membrane

    NASA Astrophysics Data System (ADS)

    Lee, Ming-Tsung; Vishnyakov, Aleksey; Neimark, Alexander V.

    2016-01-01

    Using dissipative particle dynamics (DPD), we simulate nanoscale segregation, water diffusion, and proton conductivity in hydrated sulfonated polystyrene (sPS). We employ a novel model [Lee et al. J. Chem. Theory Comput. 11(9), 4395-4403 (2015)] that incorporates protonation/deprotonation equilibria into DPD simulations. The polymer and water are modeled by coarse-grained beads interacting via short-range soft repulsion and smeared charge electrostatic potentials. The proton is introduced as a separate charged bead that forms dissociable Morse bonds with the base beads representing water and sulfonate anions. Morse bond formation and breakup artificially mimics the Grotthuss mechanism of proton hopping between the bases. The DPD model is parameterized by matching the proton mobility in bulk water, dissociation constant of benzenesulfonic acid, and liquid-liquid equilibrium of water-ethylbenzene solutions. The DPD simulations semi-quantitatively predict nanoscale segregation in the hydrated sPS into hydrophobic and hydrophilic subphases, water self-diffusion, and proton mobility. As the hydration level increases, the hydrophilic subphase exhibits a percolation transition from isolated water clusters to a 3D network. The analysis of hydrophilic subphase connectivity and water diffusion demonstrates the importance of the dynamic percolation effect of formation and breakup of temporary junctions between water clusters. The proposed DPD model qualitatively predicts the ratio of proton to water self-diffusion and its dependence on the hydration level that is in reasonable agreement with experiments.

  8. Comparison of colorimetric and membrane introduction mass spectrometry techniques for chloramine analysis.

    PubMed

    Lee, Wontae; Westerhoff, Paul; Yang, Xin; Shang, Chii

    2007-07-01

    Three methods for the determination of chloramines in water were compared using pH-buffered nanopure water and natural organic matter (NOM) solutions. We investigated whether the N,N-diethyl-p-phenylenediamine (DPD) colorimetric method and/or an adapted indophenol method (Hach MonochlorF) are suitable for determining the concentration of monochloramine in drinking water. Membrane introduction mass spectrometry (MIMS) was used as a reference analysis method to determine the different chloramine species in water. All methods measured monochloramine accurately in Nanopure water, but the DPD colorimetric method measured higher residuals (inorganic and organic chloramines) than MonochlorF or MIMS when in the presence of NOM due to organic chloramines. The indophenol method (MonochlorF) accurately detected only monochloramine and not other chloramine forms. Overall, the monochloramine concentration measured by MonochlorF was comparable with the MIMS results. A combined chlorine residual approach by the DPD colorimetric method does not differentiate between monochloramine and organic chloramines. Therefore, DPD colorimetric methods can overestimate disinfection efficacy in chloraminated water systems because of interference from organic chloramines that have no or poor bactericidal ability. Compared with the DPD colorimetric method, MonochlorF is a better choice for chloraminated water systems.

  9. Structural and dynamic characterization of ultrafine fibers based on the poly-3-hydroxybutyrate-dipyridamole system

    NASA Astrophysics Data System (ADS)

    Olkhov, A. A.; Karpova, S. G.; Staroverova, O. V.; Krutikova, A. A.; Orlov, N. A.; Kucherenko, E. L.; Iordanskii, A. L.

    2016-11-01

    The fibrous materials (the mats) based on poly-3-hydroxybutyrate (PHB) containing the drug, dipiridomole (DPD) were produced by electrospinning (ES). Thermophysical and dynamical properties of the single filaments and the mats were studied by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and probe electron paramagnetic resonance spectroscopy (EPR). The effect of annealing temperature on the structure and crystallinity of the fibers was examined. It was shown that the loading of DPD influences on both the melting enthalpy and the morphology of the fibers. Besides the analysis of EPR spectra revealed that there are two populations of spin-probes distributed in the rigid and nonrigid amorphous regions of the PHB fibers respectively. For all fibrous materials with different content of DPD (0-5%) the correlation between thermophysical (DSC) and dynamic data (EPR) was observed.

  10. Measurements of excess heat from a Pons-Fleischmann type electrolytic cell using palladium sheet

    SciTech Connect

    Storms, E.K.

    1992-09-01

    Two pieces of palladium sheet were loaded with deuterium in a Pons-Fleischmann type electrolytic cell and measurements were made of heat production. One sheet produced a steady increase in excess power that reached 7.5 watts (20% of input power) before the study was interrupted. A second similar sheet from a different batch of palladium did not produce any measurable excess power. There was a difference between the loading behavior, the maximum stoichiometry, and the presence of excess volume in the deuteride made from these materials. The first sheet contained 0.8% excess volume after deloading from D/Pd=0.82 to D/Pd=0.73, and the second sheet contained 13.5 % excess volume while at D/Pd=0.75. The high excess volume in the latter case is an indication of internal cracks.

  11. Measurements of excess heat from a Pons-Fleischmann type electrolytic cell using palladium sheet

    SciTech Connect

    Storms, E.K.

    1992-01-01

    Two pieces of palladium sheet were loaded with deuterium in a Pons-Fleischmann type electrolytic cell and measurements were made of heat production. One sheet produced a steady increase in excess power that reached 7.5 watts (20% of input power) before the study was interrupted. A second similar sheet from a different batch of palladium did not produce any measurable excess power. There was a difference between the loading behavior, the maximum stoichiometry, and the presence of excess volume in the deuteride made from these materials. The first sheet contained 0.8% excess volume after deloading from D/Pd=0.82 to D/Pd=0.73, and the second sheet contained 13.5 % excess volume while at D/Pd=0.75. The high excess volume in the latter case is an indication of internal cracks.

  12. Mesoscopic simulation of a thinning liquid bridge using the dissipative particle dynamics method.

    PubMed

    Mo, Chao-jie; Yang, Li-jun; Zhao, Fei; Cui, Kun-da

    2015-08-01

    In this research, the dissipative particle dynamics method was used to investigate the problem of thinning and breakup in a liquid bridge. It was found that both the inertial-force-dominated thinning process and the thermal-fluctuation-dominated thinning process can be reproduced with the dissipative particle dynamics (DPD) method by varying the simulation parameters. A highly suspect viscous thinning regime was also found, but the conclusion is not irrefutable because of the complication of the shear viscosity of DPD fluid. We show in this article that the DPD method can serve as a good candidate to elucidate crossover problem in liquid bridge thinning from being hydrodynamics dominated to being thermal fluctuation dominated.

  13. Consistent scaling of thermal fluctuations in smoothed dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Vázquez-Quesada, Adolfo; Ellero, Marco; Español, Pep

    2009-01-01

    Dissipative particle dynamics (DPD) as a model of fluid particles suffers from the problem that it has no physical scale associated with the particles. Therefore, a DPD simulation requires an ambiguous fine-tuning of the model parameters with the physical parameters. A corrected version of DPD that does not suffer from this problem is smoothed dissipative particle dynamics (SDPD) [P. Español and M. Revenga, Phys. Rev. E 67, 026705 (2003)]. SDPD is, in fact, a version of the well-known smoothed particle hydrodynamics method, albeit with the proper inclusion of thermal fluctuations. Here, we show that SDPD produces the proper scaling of the fluctuations as the resolution of the simulation is varied. This is investigated in two problems: the Brownian motion of a spherical colloidal particle and a polymer molecule in suspension.

  14. Dissipative particle dynamics simulation of flow generated by two rotating concentric cylinders: II. Lateral dissipative and random forces

    NASA Astrophysics Data System (ADS)

    Filipovic, N.; Haber, S.; Kojic, M.; Tsuda, A.

    2008-02-01

    Traditional DPD methods address dissipative and random forces exerted along the line connecting neighbouring particles. Espanol (1998 Phys. Rev. E 57 2930-48) suggested adding dissipative and random force components in a direction perpendicular to this line. This paper focuses on the advantages and disadvantages of such an addition as compared with the traditional DPD method. Our benchmark system comprises fluid initially at rest occupying the space between two concentric cylinders rotating with various angular velocities. The effect of the lateral force components on the time evolution of the simulated velocity profile was also compared with that of the known analytical solution. The results show that (i) the solution accuracy at steady state has improved and the error has been reduced by at least 30% (in one case by 75%), (ii) the DPD time to reach steady state has been halved, (iii) the CPU time has increased by only 30%, and (iv) no significant differences exist in density and temperature distributions.

  15. Consistent scaling of thermal fluctuations in smoothed dissipative particle dynamics.

    PubMed

    Vázquez-Quesada, Adolfo; Ellero, Marco; Español, Pep

    2009-01-21

    Dissipative particle dynamics (DPD) as a model of fluid particles suffers from the problem that it has no physical scale associated with the particles. Therefore, a DPD simulation requires an ambiguous fine-tuning of the model parameters with the physical parameters. A corrected version of DPD that does not suffer from this problem is smoothed dissipative particle dynamics (SDPD) [P. Espanol and M. Revenga, Phys. Rev. E 67, 026705 (2003)]. SDPD is, in fact, a version of the well-known smoothed particle hydrodynamics method, albeit with the proper inclusion of thermal fluctuations. Here, we show that SDPD produces the proper scaling of the fluctuations as the resolution of the simulation is varied. This is investigated in two problems: the Brownian motion of a spherical colloidal particle and a polymer molecule in suspension.

  16. Simulating the frontal instability of lock-exchange density currents with dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Li, Yanggui; Geng, Xingguo; Wang, Heping; Zhuang, Xin; Ouyang, Jie

    2016-06-01

    The frontal instability of lock-exchange density currents is numerically investigated using dissipative particle dynamics (DPD) at the mesoscopic particle level. For modeling two-phase flow, the “color” repulsion model is adopted to describe binary fluids according to Rothman-Keller method. The present DPD simulation can reproduce the flow phenomena of lock-exchange density currents, including the lobe-and-cleft instability that appears at the head, as well as the formation of coherent billow structures at the interface behind the head due to the growth of Kelvin-Helmholtz instability. Furthermore, through the DPD simulation, some small-scale characteristics can be observed, which are difficult to be captured in macroscopic simulation and experiment.

  17. A theoretical investigation into the conformational changes of dibenzo- p-dioxin, thianthrene, and selenanthrene

    NASA Astrophysics Data System (ADS)

    Kim, Sunghwan; Kwon, Younghi; Lee, Jong-Phil; Choi, Seung-Youl; Choo, Jaebum

    2003-08-01

    Theoretical ab initio calculations using the HF and B3LYP methods have been carried out to investigate the conformational differences of three cyclic rings, dibenzo- p-dioxin (DPD), thianthrene (THT), and selenanthrene (SET). The physical origin for the conformational preference of each molecule has been studied using the natural bond orbital (NBO) analysis. The NBO results indicate that DPD exists in a planar form due to strong electron delocalization caused by the specific orbital interaction, nπ→ πCC∗, around the X atom. On the other hand, THT and SET exist as puckered forms with high inversion barriers due to less effective electron delocalization. The NBO analysis also shows that the conformational stabilization in DPD is caused by a more effective overlap of the 2 pz- πCC∗ orbitals, compared with the overlap of the 3 pz- πCC∗ orbitals in THT.

  18. Mesoscopic simulation of a thinning liquid bridge using the dissipative particle dynamics method

    NASA Astrophysics Data System (ADS)

    Mo, Chao-jie; Yang, Li-jun; Zhao, Fei; Cui, Kun-da

    2015-08-01

    In this research, the dissipative particle dynamics method was used to investigate the problem of thinning and breakup in a liquid bridge. It was found that both the inertial-force-dominated thinning process and the thermal-fluctuation-dominated thinning process can be reproduced with the dissipative particle dynamics (DPD) method by varying the simulation parameters. A highly suspect viscous thinning regime was also found, but the conclusion is not irrefutable because of the complication of the shear viscosity of DPD fluid. We show in this article that the DPD method can serve as a good candidate to elucidate crossover problem in liquid bridge thinning from being hydrodynamics dominated to being thermal fluctuation dominated.

  19. Analysis of the effects of disk tilt on the differential-phase-detection signal in a high-density DVD read-only disk driver.

    PubMed

    Shen, Quanhong; Xu, Duanyi

    2006-06-10

    A high-density DVD (HD-DVD) is one of the high-density optical storage technology newly designed to meet the demands of high-definition video broadcasting that is very sensitive to the radial tilt of a disk. An analytic model based on diffraction theory is presented in detail to calculate the tracking error signal of a HD-DVD read-only disk driver by using the differential-phase-detection (DPD) method when radial tilt of a disk occurs. The effects of the tilt on a DPD signal in a HD-DVD read-only disk driver are quantified and compared to those in a DVD read-only disk driver. Experimental measurements for the DPD signal under different radial tilt angles in a HD-DVD read-only disk driver are also reported.

  20. A five-factor model description of depressive personality disorder.

    PubMed

    Vachon, David D; Sellbom, Martin; Ryder, Andrew G; Miller, Joshua D; Bagby, R Michael

    2009-10-01

    This investigation extends previous work on Five-Factor Model (FFM) personality disorder profiles. Specifically, a FFM expert consensus prototype for Depressive Personality Disorder (DPD) using the 30 facets of the NEO Personality Inventory-Revised (NEO PI-R) was developed. Initial validation of this prototype in a psychiatric population employed several clinical scales. When combined with trait information yielded by criteria translation and empirical approaches, the composite FFM profile emphasized several facets that represent the core components of DPD. In addition to several traits represented by the current DSM conceptualization of DPD, such as depressiveness, anxiousness, self-consciousness, and low tendermindedness, the composite profile was also characterized by several unrepresented traits, such as high modesty and low positive emotionality, warmth, assertiveness, trust, and achievement striving. Future definitions of depressive personality, conceptualized either as a DSM-V personality disorder or as a multifaceted construct, should consider these additional traits.

  1. Use of the Daily Phone Diary to Study Religiosity and Mood: Convergent Validity.

    PubMed

    Szczesniak, Rhonda D; Zou, Yuanshu; Dimitriou, Sophia M; Quittner, Alexandra L; Grossoehme, Daniel H

    2017-01-01

    Studies of religious/spiritual behavior frequently rely on self-reported questionnaire data, which is susceptible to bias. The Daily Phone Diary (DPD) was developed to minimize bias in reporting activities and behavior across a 24-hour period. A cross-sectional study of 126 parents of children with cystic fibrosis was used to establish the validity of the DPD to study religious/spiritual behaviors. Longitudinal models were used to determine the odds of improved mood during religious/spiritual activities. Convergent validity was found. Participants had increased odds of improved mood during religious/spiritual activities compared to nonreligious/spiritual activities. Associations with gender and religious affiliations were found. The DPD is a valid tool for studying religious/spiritual activities and opens novel avenues for chaplaincy research and the development of chaplaincy interventions incorporating these findings.

  2. Gaussian-inspired auxiliary non-equilibrium thermostat (GIANT) for Dissipative Particle Dynamics simulations

    NASA Astrophysics Data System (ADS)

    Jamali, Safa; Boromand, Arman; Khani, Shaghayegh; Maia, Joao

    2015-12-01

    We present in this letter an auxiliary thermostat for non-equilibrium simulations in Dissipative Particle Dynamics based on the Gaussian distribution of particle velocities in the fluid. We demonstrate the ability of the thermostat to maintain the temperature under a wide range of shear rates and dissipative parameters, and to extend the shear rate window accessible by DPD significantly. The effect of proposed method on the viscosity of a DPD fluid is studied which is particularly of interest when the rheological behavior of a complex fluids is subject of DPD simulations. Furthermore, performance of the proposed method is compared to the ones from the well-known Lowe-Andersen scheme in regards to temperature and viscosity measurements.

  3. Maladaptive variants of conscientiousness and agreeableness.

    PubMed

    Samuel, Douglas B; Gore, Whitney L

    2012-12-01

    Although reasonably strong support has been obtained for the Five-Factor Model's (FFM) ability to account for the existing personality disorder (PD) constructs, the support for obsessive-compulsive PD (OCPD) and dependent PD (DPD) has been relatively less consistent. Specifically, the expected correlation between OCPD and the FFM trait of Conscientiousness has varied in magnitude across studies while DPD has, at times, also evinced rather weak relationships with FFM Agreeableness. We determined that these inconsistencies were due primarily to the reliance on FFM measures that lack adequate fidelity to assess the maladaptive aspects of high Conscientiousness and Agreeableness. When alternative measures were utilized, the correlations were generally large and in line with expectations. We conclude that OCPD and DPD can be fruitfully conceptualized within the FFM but encourage the use of measures that provide a comprehensive assessment of both the adaptive and maladaptive aspects of the FFM traits. © 2012 The Authors. Journal of Personality © 2012, Wiley Periodicals, Inc.

  4. Particle-layering effect in wall-bounded dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Litvinov, Sergey; Ellero, Marco; Hu, Xiangyu; Adams, Nikolaus A.

    2010-12-01

    Dissipative particle dynamics (DPD) is a mesoscopic simulation method that describes “clusters” of molecules as a single numerical particle. DPD is a very effective method but it introduces numerical artifacts through the coarse-graining procedure, such as particle ordering in the near-wall region. These artifacts can result in nonphysical phenomena during a simulation of a polymer tethered to the wall undergoing shear flow: polymer sticking and overextension for higher shear rates. In this paper we report that a version of DPD with a so-called solidification boundary formulation and conservative-force interactions based on the equation of state allows to reduce number density fluctuations in near-wall region significantly.

  5. Dissipative Particle Dynamics Simulations for Phospholipid Membranes Based on a Four-To-One Coarse-Grained Mapping Scheme

    PubMed Central

    Li, Xiaoxu; Gao, Lianghui; Fang, Weihai

    2016-01-01

    In this article, a new set of parameters compatible with the dissipative particle dynamics (DPD) force field is developed for phospholipids. The coarse-grained (CG) models of these molecules are constructed by mapping four heavy atoms and their attached hydrogen atoms to one bead. The beads are divided into types distinguished by charge type, polarizability, and hydrogen-bonding capacity. First, we derive the relationship between the DPD repulsive force and Flory-Huggins χ-parameters based on this four-to-one CG mapping scheme. Then, we optimize the DPD force parameters for phospholipids. The feasibility of this model is demonstrated by simulating the structural and thermodynamic properties of lipid bilayer membranes, including the membrane thickness, the area per lipid, the lipid tail orientation, the bending rigidity, the rupture behavior, and the potential of mean force for lipid flip-flop. PMID:27137463

  6. Use of Daily Phone Diary to study religiosity and mood: Convergent validity

    PubMed Central

    Szczesniak, Rhonda D.; Zou, Yuanshu; Dimitriou, Sophia M.; Quittner, Alexandra L.; Grossoehme, Daniel H.

    2017-01-01

    Studies of religious/spiritual behavior frequently rely on self-reported questionnaire data, which is susceptible to bias. The Daily Phone Diary (DPD) was developed to minimize bias in reporting activities and behavior across a 24-hour period. A cross-sectional study of 126 parents of children with cystic fibrosis was used to establish the validity of the DPD to study religious/spiritual behaviors. Longitudinal models were used to determine the odds of improved mood during religious/spiritual activities. Convergent validity was found. Participants had increased odds of improved mood during religious/spiritual activities compared to non-religious/spiritual activities. Associations with gender and religious affiliations were found. The DPD is a valid tool for studying religious/spiritual activities and opens novel avenues for chaplaincy research and the development of chaplaincy interventions incorporating these findings. PMID:27869567

  7. Altered patterns of heartbeat-evoked potentials in depersonalization/derealization disorder: neurophysiological evidence for impaired cortical representation of bodily signals.

    PubMed

    Schulz, André; Köster, Susann; Beutel, Manfred E; Schächinger, Hartmut; Vögele, Claus; Rost, Silke; Rauh, Manfred; Michal, Matthias

    2015-06-01

    Core features of depersonalization/derealization disorder (DPD) are emotional numbing and feelings of disembodiment. Although there are several neurophysiological findings supporting subjective emotional numbing, the psychobiology of disembodiment remains unclear. Heartbeat-evoked potentials (HEPs), which are considered psychophysiological indicators for the cortical representation of afferent signals originating from the cardiovascular system, were assessed in 23 patients with DPD and 24 healthy control individuals during rest and while performing a heartbeat perception task. Absolute HEP amplitudes did not differ between groups. Nevertheless, healthy individuals showed higher HEPs during the heartbeat perception task than during rest, whereas no such effect was found in patients with DPD (p = .031). Patients with DPD had higher total levels of salivary α-amylase than did healthy individuals (9626.6 [8200.0] versus 5344.3 [3745.8] kU min/l; p = .029), but there were no group differences in cardiovascular measures (heart rate = 76.2 [10.1] versus 74.3 [7.5] beats/min, p = .60; normalized low-frequency heart rate variability = 0.63 [0.15] versus 0.56 [0.15] normalized units, p = .099; low frequency/high frequency ratio = 249.3 [242.7] versus 164.8 [108.8], p = .10), salivary cortisol (57.5 [46.7] versus 55.1 [43.6] nmol min/l, p = .86), or cortisone levels (593.2 [260.3] versus 543.8 [257.1] nmol min/l, p = .52). These results suggest altered cortical representation of afferent signals originating from the cardiovascular system in patients with DPD, which may be associated with higher sympathetic tone. These findings may reflect difficulties of patients with DPD to attend to their actual bodily experiences.

  8. Effects of a bolus injection of 5-fluorouracil on dihydropyrimidine dehydrogenase activity in rats receiving continuous infusion of 5-fluorouracil.

    PubMed

    Kobuchi, Shinji; Hayashi, Asuka; Taniguchi, Mayu; Ito, Yukako; Tamura, Takao; Sakaeda, Toshiyuki

    2016-09-01

    The options for improving the chemotherapeutic regimen consisting of bolus plus infusion of 5-fluorouracil (5-FU) include omitting the 5-FU bolus injection. We examined the effects of a 5-FU bolus injection on the activity of dihydropyrimidine dehydrogenase (DPD), which is the first and rate-limiting enzyme of 5-FU catabolism, in rats. The rats were divided into three groups, and then continuous infusion (50 mg/m(2)/h) for 4 h was started with a bolus injection of saline, 20 mg/kg 5-FU, or 60 mg/kg 5-FU. Plasma 5-FU, uracil (Ura), dihydrouracil (UH2) levels, and hepatic DPD activity were determined after administration of 5-FU. The half-life after the end of the infusion (t 1/2, 4-8 h) of 5-FU in the rats given the bolus injection was significantly longer than in those that had been given saline, and it increased with increasing 5-FU bolus injection dosage (r = 0.801, p < 0.01). The plasma UH2/Ura ratio, an indirect biomarker of hepatic DPD activity, tended to be lower in the rats that had received a 5-FU bolus injection than in those that had not, and it remained low after infusion ended. The hepatic DPD activity in rats that had received a 5-FU bolus injection was significantly lower than in those that had not. Negative correlation was observed between DPD activity and bolus injection dosage (r = -0.691, p < 0.05). A bolus injection suppresses hepatic DPD activity and its effects are dependent on dosage, resulting in slower elimination of 5-FU from the blood and contributing to long-term systemic exposure to 5-FU.

  9. Danish Palliative Care Database

    PubMed Central

    Groenvold, Mogens; Adsersen, Mathilde; Hansen, Maiken Bang

    2016-01-01

    Aims The aim of the Danish Palliative Care Database (DPD) is to monitor, evaluate, and improve the clinical quality of specialized palliative care (SPC) (ie, the activity of hospital-based palliative care teams/departments and hospices) in Denmark. Study population The study population is all patients in Denmark referred to and/or in contact with SPC after January 1, 2010. Main variables The main variables in DPD are data about referral for patients admitted and not admitted to SPC, type of the first SPC contact, clinical and sociodemographic factors, multidisciplinary conference, and the patient-reported European Organisation for Research and Treatment of Cancer Quality of Life Questionaire-Core-15-Palliative Care questionnaire, assessing health-related quality of life. The data support the estimation of currently five quality of care indicators, ie, the proportions of 1) referred and eligible patients who were actually admitted to SPC, 2) patients who waited <10 days before admission to SPC, 3) patients who died from cancer and who obtained contact with SPC, 4) patients who were screened with European Organisation for Research and Treatment of Cancer Quality of Life Questionaire-Core-15-Palliative Care at admission to SPC, and 5) patients who were discussed at a multidisciplinary conference. Descriptive data In 2014, all 43 SPC units in Denmark reported their data to DPD, and all 9,434 cancer patients (100%) referred to SPC were registered in DPD. In total, 41,104 unique cancer patients were registered in DPD during the 5 years 2010–2014. Of those registered, 96% had cancer. Conclusion DPD is a national clinical quality database for SPC having clinically relevant variables and high data and patient completeness. PMID:27822111

  10. Gene expression in colorectal cancer and in vitro chemosensitivity to 5-fluorouracil: a study of 88 surgical specimens.

    PubMed

    Yoshinare, Kentaro; Kubota, Tetsuro; Watanabe, Masahiko; Wada, Norihito; Nishibori, Hideki; Hasegawa, Hirotoshi; Kitajima, Masaki; Takechi, Teiji; Fukushima, Masakazu

    2003-07-01

    To predict the sensitivity of colorectal cancer to 5-fluorouracil (5-FU), we compared the gene expression of surgically obtained colorectal cancer specimens with chemosensitivity to 5-FU as detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay. Eighty-eight patients with advanced and/or metastatic colorectal cancer provided written informed consent and entered the trial from September 2000 to October 2001. Fresh surgical specimens were used for the MTT assay, and sensitivity to 5-FU was evaluated at a cutoff concentration of 50 microg/ml and 48-h incubation time. Frozen samples were stored at - 80 degrees C until mRNA analysis of thymidylate synthetase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP), es-nucleoside transporter (NT), and E2F1 by real-time RT-PCR. The correlations between the variables were analyzed, and the predictive value of these mRNAs was assessed statistically using a receiver operating characteristic (ROC) curve. NT and DPD, TP and DPD, and TP and NT mRNA expression levels correlated significantly, while TS and E2F1 showed no correlations. High NT expression was associated with low sensitivity to 5-FU (P < 0.013), as were high DPD and E2F1 expression (P < 0.022 for both). High TP mRNA expression correlated with low sensitivity to 5-FU (P < 0.034), although high TS mRNA expression did not. ROC curves indicated that DPD and NT mRNAs were possible predictors of sensitivity to 5-FU, with cutoff values of 0.6 and 0.4, respectively. The sensitivity of colorectal cancer to 5-FU may be regulated by DPD, the rate-limiting enzyme of catabolism, and NT, an important transmembrane transporter of nucleosides.

  11. Myocardial uptake of bone scintigraphic agents associated with increased pulmonary uptake.

    PubMed

    Bach-Gansmo, Tore; Wien, Tale N; Løndalen, Ayca; Halvorsen, Erling

    2016-05-01

    Due to delivery problems with the most commonly used bone scintigraphic agent medronate-(99m)Tc-methylene diphosphonate (MDP) (medronate), several regional institutions changed, at various time points, to (99m)Tc-dicarboxypropane diphosphonate (DPD) (Teceos) from 2010. Extraosseous uptake, in particular, myocardial uptake, was observed in a number of patient examined with DPD, with reduced quality of the bone scans. Additionally, an increase in pulmonary uptake was apparent in many of these patients. The aim of this quality control was to assess pulmonary soft tissue uptake in the patients with high myocardial uptake. A retrospective analysis of the 2435 bone scintigraphies performed during a 3-year period revealed relatively intense myocardial uptake in 10 of the 1195 patients examined with DPD (Teceos). A comparison of pulmonary uptake in a control group of age- and gender-matched subjects and a control group of patients examined with the same preparation of DPD were assessed. In patients with cardiac uptake of DPD, it could also be shown a relatively intense background uptake in the lungs with significantly higher uptake ratio over intercostals regions versus the abdomen, compared to the control groups. Furthermore, we found, as already well documented, a significantly lower bone to soft tissue uptake in these patients, as quantified by a femur to surrounding soft tissue ratio. Cardiac uptake of bone scintigraphic agents is associated with high pulmonary uptake. This may be a sign of pulmonary involvement which may give extraosseous bone tracer uptake its own importance and DPD a new role. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  12. Perspective: Dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Español, Pep; Warren, Patrick B.

    2017-04-01

    Dissipative particle dynamics (DPD) belongs to a class of models and computational algorithms developed to address mesoscale problems in complex fluids and soft matter in general. It is based on the notion of particles that represent coarse-grained portions of the system under study and allow, therefore, reaching time and length scales that would be otherwise unreachable from microscopic simulations. The method has been conceptually refined since its introduction almost twenty five years ago. This perspective surveys the major conceptual improvements in the original DPD model, along with its microscopic foundation, and discusses outstanding challenges in the field. We summarize some recent advances and suggest avenues for future developments.

  13. Mesoscale simulation of polymer reaction equilibrium: Combining dissipative particle dynamics with reaction ensemble Monte Carlo. II. Supramolecular diblock copolymers

    NASA Astrophysics Data System (ADS)

    Lísal, Martin; Brennan, John K.; Smith, William R.

    2009-03-01

    We present an alternative formulation of the reaction ensemble dissipative particle dynamics (RxDPD) method [M. Lísal, J. K. Brennan, and W. R. Smith, J. Chem. Phys. 125, 16490 (2006)], a mesoscale simulation technique for studying polymer systems in reaction equilibrium. The RxDPD method combines elements of dissipative particle dynamics (DPD) and reaction ensemble Monte Carlo (RxMC), and is primarily targeted for the prediction of the system composition, thermodynamic properties, and phase behavior of reaction equilibrium polymer systems. The alternative formulation of the RxDPD method is demonstrated by considering a supramolecular diblock copolymer (SDC) melt in which two homopolymers, An and Bm, can reversibly bond at terminal binding sites to form a diblock copolymer, AnBm. We consider the effect of the terminal binding sites and the chemical incompatibility between A- and B-segments on the phase behavior. Both effects are found to strongly influence the resulting phase behavior. Due to the reversible nature of the binding, the SDC melt can be treated as the reaction equilibrium system An+Bm⇌AnBm. To simulate the An+Bm⇌AnBm melt, the system contains, in addition to full An, Bm, and AnBm polymers, two fractional polymers: one fractional polymer either fAn or fBm, and one fractional polymer fAnBm, which have fractional particles at the ends of the polymer chains. These fractional particles are coupled to the system via a coupling parameter. The time evolution of the system is governed by the DPD equations of motion, accompanied by random changes in the coupling parameter. Random changes in the coupling parameter mimic forward and reverse reaction steps as in the RxMC approach, and they are accepted with a probability derived from the expanded ensemble grand canonical partition function. Unlike the original RxDPD method that considers coupling of entire fractional polymers to the system, the expanded ensemble framework allows a stepwise coupling, thus

  14. Tracking and Trapping a Hacker: An Actual Takedown

    DTIC Science & Technology

    2010-04-01

    1 Fi led 06/26/2009 Page 18 of 19 ( DPD ) aviation unit. Detective Bill Cox, a DPD officer working with the. FBJ tn a task force role, c.onfinned that...Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per...to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1 . REPORT DATE APR

  15. Dissipative particle dynamics simulation of contact angle hysteresis on a patterned solid/air composite surface.

    PubMed

    Kong, Bin; Yang, Xiaozhen

    2006-02-28

    We have studied two types of topological substrates--the continuous solid substrates (CSS) and the discontinuous solid substrates (DSS)--by using the dissipative particle dynamics (DPD) method for a better understanding of the contact angle hysteresis on two such substrates. After the validation of DPD in the system, we found that DSS has a different distribution of the metastable states from that of CSS and that DSS has relatively larger contact angle hysteresis at lower temperature. Obtained results also show that CSS is more suitable for making an ultrahydrophobic or ultralyophobic surface than DSS from the point of view of dynamic wettability.

  16. FY04-Q4 REPORT: LX-17 MODELING

    SciTech Connect

    Gee, R; Fried, L

    2004-11-30

    TATB containing explosives tend to permanently expand as their temperatures are increased or thermally cycled, a phenomenon known as ''ratchet-growth.'' Mesoscale simulations using dissipative particle dynamics (DPD) have been carried out in order to study the geometric packing effects of TATB pressed powders under stress conditions. Further, our mesoscale simulations of polycrystalline TATB pressed powders have been used to predict hot-spot changes as a function of temperature (thermal cycling) and confinement. Our DPD simulations showed irreversible permanent growth in the mesoscale pressed powders only when crystal fracture induced by the anisotropic thermal expansion of TATB was incorporated into the model.

  17. Dissipative particle dynamics simulation on paclitaxel loaded PEO-PPO-PEO block copolymer micelles.

    PubMed

    Wang, Zhigao; Jiang, Jie

    2014-03-01

    Self-assembly behavior of the polymer drug loading micelle PEO-PPO-PEO was studied using dissipative particle dynamics (DPD) simulation method with various simulation steps. The distributions of drugs in polymer carriers were also investigated with different drug feed ratios. Polymer carriers distributed on the surface of the spherical micelle, and drugs were almost encapsulated in the inner of the micelle. Our simulation work demonstrates that the DPD simulation is effective to study the drug loaded systems and can give useful guidance on the design and preparation of new drug carriers with tailored properties.

  18. Perspective: Dissipative particle dynamics.

    PubMed

    Español, Pep; Warren, Patrick B

    2017-04-21

    Dissipative particle dynamics (DPD) belongs to a class of models and computational algorithms developed to address mesoscale problems in complex fluids and soft matter in general. It is based on the notion of particles that represent coarse-grained portions of the system under study and allow, therefore, reaching time and length scales that would be otherwise unreachable from microscopic simulations. The method has been conceptually refined since its introduction almost twenty five years ago. This perspective surveys the major conceptual improvements in the original DPD model, along with its microscopic foundation, and discusses outstanding challenges in the field. We summarize some recent advances and suggest avenues for future developments.

  19. On the comparisons between dissipative particle dynamics simulations and self-consistent field calculations of diblock copolymer microphase separation

    NASA Astrophysics Data System (ADS)

    Sandhu, Paramvir; Zong, Jing; Yang, Delian; Wang, Qiang

    2013-05-01

    To highlight the importance of quantitative and parameter-fitting-free comparisons among different models/methods, we revisited the comparisons made by Groot and Madden [J. Chem. Phys. 108, 8713 (1998), 10.1063/1.476300] and Chen et al. [J. Chem. Phys. 122, 104907 (2005), 10.1063/1.1860351] between their dissipative particle dynamics (DPD) simulations of the DPD model and the self-consistent field (SCF) calculations of the "standard" model done by Matsen and Bates [Macromolecules 29, 1091 (1996), 10.1021/ma951138i] for diblock copolymer (DBC) A-B melts. The small values of the invariant degree of polymerization used in the DPD simulations do not justify the use of the fluctuation theory of Fredrickson and Helfand [J. Chem. Phys. 87, 697 (1987), 10.1063/1.453566] by Groot and Madden, and their fitting between the DPD interaction parameters and the Flory-Huggins χ parameter in the "standard" model also has no rigorous basis. Even with their use of the fluctuation theory and the parameter-fitting, we do not find the "quantitative match" for the order-disorder transition of symmetric DBC claimed by Groot and Madden. For lamellar and cylindrical structures, we find that the system fluctuations/correlations decrease the bulk period and greatly suppress the large depletion of the total segmental density at the A-B interfaces as well as its oscillations in A- and B-domains predicted by our SCF calculations of the DPD model. At all values of the A-block volume fractions in the copolymer f (which are integer multiples of 0.1), our SCF calculations give the same sequence of phase transitions with varying χN as the "standard" model, where N denotes the number of segments on each DBC chain. All phase boundaries, however, are shifted to higher χN due to the finite interaction range in the DPD model, except at f = 0.1 (and 0.9), where χN at the transition between the disordered phase and the spheres arranged on a body-centered cubic lattice is lower due to N = 10 in the DPD

  20. Antioxidant assay using genetically engineered bioluminescent Escherichia coli

    NASA Astrophysics Data System (ADS)

    Bartolome, Amelita; Macalino, Bernadette; Pastoral, Ian Lemuel; Sevilla, Fortunato, III

    2006-02-01

    A new antioxidant activity assay based on the reactive oxygen species (ROS)-inducible bacterial strain (E. coli DPD2511) is described. The strain harbors the plasmid pKatG::luxCDABE and responds to hydrogen peroxide treatment by increasing light emission at 490 nm. Antioxidant capacity is evaluated through the ability of an agent to inhibit the hydrogen peroxide-induced bioluminescence of E. coli DPD2511. Applicability of the developed assay in detecting levels of antioxidants in various aqueous plant extracts is demonstrated. The assay was validated against 2,2-diphenylpicrylhydrazyl (DPPH) assay, a known antioxidant assay.

  1. UNDERNUTRITION, SERUM VITAMIN B12, FOLIC ACID AND DEPRESSIVE SYMPTOMS IN OLDER ADULTS.

    PubMed

    Brito Noronha, Mafalda; Almeida Cunha, Nathalie; Agra Araújo, Daniela; Flamínio Abrunhosa, Sofia; Nunes Rocha, Ada; Freitas Amaral, Teresa

    2015-07-01

    Antecedentes: la cuestión del posible vínculo entre la desnutrición y los síntomas depresivos, considerando el efecto de las deficiencias de vitamina B12 y de folato, es de importancia práctica porque estas son potencialmente prevenibles y tratables. Este estudio tiene como objetivo evaluar si la desnutrición está relacionada con los síntomas depresivos, teniendo en cuenta el efecto de los niveles plasmáticos de vitamina B12 y de folato. Método: un estudio transversal se llevó a cabo en una muestra de 84 adultos mayores que viven en hogares de cuidado. Se obtuvieron datos sobre el estado nutricional utilizando Mini-Nutritional Assessment, los niveles séricos de ácido fólico y vitamina B12, la capacidad cognitiva, la dependencia funcional, y/o los síntomas de comportamiento depresivo. Los síntomas de depresión se midieron utilizando la versión de 20 ítems de la Escala de Depresión del Centro de Estudios Epidemiológicos. Resultados: cincuenta y tres adultos mayores estaban en riesgo de depresión (63,1%). De ellos, el 34% estaban en riesgo de desnutrición. Aunque se encontró una alta frecuencia de adultos mayores con bajos niveles plasmáticos de vitamina B12 (42,9%) y niveles más bajos de ácido fólico (5,9%), no se encontraron diferencias significativas en relación con la existencia de síntomas depresivos. En el análisis multivariable se observó un aumento en el riesgo de depresión entre los participantes con riesgo nutricional OR = 3,47 (1,05 a 11,46), mientras tener bajos niveles de ácido fólico y vitamina B12 no se asociaron con el riesgo de depresión. Conclusión: entre los adultos mayores desnutridos se observó un aumento en el riesgo de depresión, independientemente del ácido fólico y del estado de la vitamina B12. Estos resultados ponen de manifiesto la necesidad de implementar estrategias preventivas, especialmente dirigidas a los adultos mayores que viven en hogares de cuidado.

  2. Global skeletal uptake of 99mTc-methylene diphosphonate (GSU) in patients affected by endocrine diseases: comparison with biochemical markers of bone turnover.

    PubMed

    Scillitani, A; Dicembrino, F; Chiodini, I; Minisola, S; Fusilli, S; Di Giorgio, A; Garrubba, M; D'Aloiso, L; Frusciante, V; Torlontano, M; Modoni, S; Trischitta, V; Trischitta, V; Carnevale, V

    2002-10-01

    This study aimed to clinically validate the global skeletal uptake (GSU) of (99m)Tc-methylene diphosphonate ((99m)Tc-MDP), and to compare it with a marker of bone formation (i.e. serum osteocalcin or OC) and an index of bone resorption (i.e. urinary deoxypyridinoline or U-DPD) in different endocrine disorders affecting the skeleton. We studied 29 female patients with thyrotoxicosis (TT), 27 with primary hyperparathyroidism (PHPT), 16 with acromegaly (AC), 15 with Cushing's syndrome (CS), and altogether 110 healthy women matched for age, BMI and menstrual status. In all subjects total body digital scan images (TBDS) were acquired at 5 min and at 4 h after the administration of (99m)Tc-MDP; the whole body retention (WBR) of the tracer was measured by counting two identical sets of rectangular ROIs, and GSU was subsequently calculated by drawing an irregular ROI on 4 h TBDS images. Serum OC was assessed by IRMA and urinary DPD by fluorometric detection after reverse phase high pressure chromatography. In TT patients GSU (40.0 +/- 5.1 vs 36.5 +/- 4.8%), OC (19.1 +/- 11.8 vs 7.1 +/- 2.9 microg/l) and U-DPD (62.4 +/- 42.7 vs 19.5 +/- 5.3 pmol/pmol) were significantly ( p<0.01) higher than in controls. PHPT patients showed GSU (47.2 +/- 6.6 vs 37.8 +/- 5.3%), OC (38.6 +/- 40.9 vs 8.2 +/- 2.5 microg/l), and U-DPD (55.0 +/- 51.3 vs 21.9 +/- 6.1 pmol/pmol) values significantly ( p<0.001) higher than controls. In CS patients, GSU (39.6 +/- 6.4 vs 32.7 +/- 3.5%; p<0.01) and U-DPD (22.8 +/- 8.4 vs 16.5 +/- 2.7 pmol/pmol; p<0.05) were higher, whereas OC (3.6 +/- 2.4 vs 5.2 +/- 1.9 mg/l; p<0,05) was lower than in controls. In AC patients, GSU (34.9 +/- 5.3 vs 35.2 +/- 3.4%) did not differ significantly from controls, whereas OC (16.8 +/- 8.8 vs 6.9 +/- 2.9 microg/l; p<0.001) and U-DPD (30.9 +/- 13.6 vs 21.0 +/- 5.7 pmol/pmol; p<0.01) were higher. Stepwise multivariate linear regression analysis was performed with disease activity, creatinine clearance, age, and years since

  3. Nuevas estrategias de gestión, tratamiento y valorización de los efluentes organicos pecuarios: Experiencias en USDA. (Management strategies for organic livestock effluents,innovative treatment and valorization)

    USDA-ARS?s Scientific Manuscript database

    En la actualidad el impacto potencial de los residuos ganaderos en el medio-ambiente representa uno de los desafíos más grandes de la agricultura. Las tecnologías de tratamiento pueden tener un importante papel en el manejo de los residuos ganaderos dando más flexibilidad en los programas de la apli...

  4. Iranian EFL and Indian ESL College Students' Beliefs about Reading Strategies in L2 (Creencias de estudiantes universitarios iraníes EFL e hindúes ESL acerca de las estrategias de lectura en L2)

    ERIC Educational Resources Information Center

    Karbalaei, Alireza

    2010-01-01

    The notion of "learner beliefs" has garnered much attention in the field of second language acquisition. Although different studies have been conducted to study learners' beliefs about language learning, little research has looked into the issue of L2 readers' beliefs and their relations to reading strategies. This study investigated…

  5. A Baseline Study of Strategies to Promote Critical Thinking in the Preschool Classroom (Un Estudio de Base sobre Estrategias para la Promoción de Pensamiento Critico en las Aulas de Preescolar)

    ERIC Educational Resources Information Center

    León, Jenny Melo

    2015-01-01

    The purpose of this study was to identify the different incidents of critical thinking in five preschool classrooms in one school, and the instructional strategies preschool teachers employed in the development of children's critical thinking. The participants in this study were five self-contained preschool teachers and their corresponding…

  6. A strategy for weight loss based on healthy dietary habits and control of emotional response to food.

    PubMed

    Pontes Torrado, Yolanda; García-Villaraco Velasco, Ana; Hernández Galiot, Ana; Goñi Cambrodón, Isabel

    2015-06-01

    Introducción: el sedentarismo y los hábitos alimentarios poco saludables son las principales causas de un balance energético negativo y un exceso de peso corporal. El estilo de vida del patrón de dieta mediterránea reduce significativamente los factores de riesgo de enfermedades no transmisibles. Por otra parte, las emociones tienen un poderoso efecto en el comportamiento alimentario. Existe una relación directa entre la elección de alimentos, las emociones y el aumento de la ingesta energética. Objetivo: conocer el comportamiento emocional de los individuos para facilitar el establecimiento de pautas dietéticas personalizadas basadas en hábitos alimentarios saludables y aumentar la fidelidad del paciente hasta conseguir el peso deseado. Material y métodos: 99 personas adultas con sobrepeso fueron sometidos a un programa de reducción de peso basado en establecer unos hábitos alimentarios y un estilo de vida saludables. La adhesión al patrón de dieta Mediterránea y el efecto de las emociones en la elección de alimentos se determinaron utilizando los cuestionarios MEDAS (Mediterranean Diet Adherence Screener) y EEQ (Emocional Eater Questionnaire), respectivamente. Resultados: la población estudiada era sedentaria, consumía una dieta poco saludable y su conducta alimentaria era dependiente de las emociones. La mayoría de los participantes (66% mujeres y 71% hombres) fueron clasificados como comedores emocionales. Durante el programa de tratamiento, los participantes modificaron sus hábitos alimentarios y su estilo de vida, consiguiendo reducir el peso corporal en al menos un 10% respecto al peso inicial. Conclusión: conocer la relación entre la ingesta de alimentos y las emociones permite personalizar la estrategia dietética para disminuir el peso corporal y la tasa de abandono.

  7. INTERVENCIÓN EDUCATIVA EFECTIVA EN VIH PARA MUJERES

    PubMed Central

    Miner, Sarah; Poupin, Lauren; Bernales, Margarita; Ferrer, Lilian; Cianelli, Rosina

    2016-01-01

    RESUMEN En Chile se estima que aproximadamente 38 mil personas viven con el Virus de Inmunodeficiencia Humana [VIH]. En el año 2001, 1.092 mujeres chilenas vivían con VIH, actualmente se cree que hay más de 7.600 mujeres con el virus. Frente a estas cifras surge la necesidad de crear estrategias de prevención dirigidas a mujeres chilenas. Objetivo analizar los estudios ya realizados en la prevención de VIH para determinar qué aspectos se deben incluir en programas exitosos de prevención de VIH en mujeres. Diseño y Método se realizó una revisión de la literatura utilizando la base de datos Proquest, CINAHL, Pubmed y Scielo. Los límites comprendieron: textos completos, de los últimos 10 años, de acceso gratuito y escrito en español o inglés. Se seleccionaron 15 artículos para la revisión. Resultados todos los artículos comprenden la evaluación del efecto de una intervención sobre conocimiento y conductas relacionadas con VIH/SIDA. Catorce muestran resultados significativos en cambios positivos de conducta o conocimientos relacionados con la prevención de VIH. Conclusiones los programas de prevención de VIH en mujeres pueden ser efectivos para lograr cambios de conducta y de conocimiento. Las intervenciones exitosas son aquellas basadas en teorías o modelos de prevención y en cambios de conductas, todas adaptadas a la cultura de la población estudiada. PMID:27667897

  8. NUTRITIONAL SUPPORT FOR FULMINANT HEPATITIS.

    PubMed

    Ramos Figueira, Estela Regina; Rocha Filho, Joel Avancini; Souto Nacif, Lucas; Carneiro D'Albuquerque, Luiz; Linetzky Waitzberg, Dan

    2015-12-01

    Introducción: la hepatitis fulminante se asocia a un exacerbado hipercatabolismo, la hipoglicemia y la hiperamonemia están acompañadas por la liberación de citocinas proinflamatorias y hormonas catabólicas en la circulación sistémica, empeorando la condición clínica del paciente. El apoyo nutricional es un elemento crucial para la recuperación de estos pacientes. Objetivos: el objetivo de esta revisión es actualizar el apoyo nutricional para la hepatitis fulminante. Métodos: la revisión se llevó a cabo mediante la búsqueda electrónica en Medline-PubMed, utilizando malla de términos. Resultados y discusión: no hay muchos datos disponibles sobre el apoyo nutricional para lahepatitis fulminante o fallo hepático agudo. Las estrategias de intervención nutricional inicial se centran en el control de los trastornos metabólicos de la hepatitis fulminante descritos anteriormente, que deben ser individualizadas de acuerdo a la gravedad de la situación clínica del paciente. Energía y proteína se pueden proporcionar en cantidades de 25‑40 kcal / kg / día y 0,8-1,2 g / kg / día, respectivamente. La terapia nutricional enteral está indicada en pacientes con encefalopatía avanzada o para aquellos que no pueden ser adecuadamente alimentados por vía oral. Se debe obtener una euglicemia y la ingesta de proteínas puede estar basada en fórmulas de BCAA. Los lípidos se pueden administrar como suplemento energético con precaución. Una terapia nutricional adecuada puede potencialmente reducir la morbilidad y la mortalidad de los pacientes con hepatitis fulminante.

  9. [A case of liver metastasis of rectal cancer demonstrating complete response to 5-FU + Leucovorin + UFT].

    PubMed

    Ishida, Hideyuki; Ohsawa, Tomonori; Takeuchi, Ikuya; Nakada, Hiroshi; Inokuma, Shigehisa; Hoshino, Takanobu; Daijo, Hashimoto

    2002-04-01

    Dihydropyrimidine dehydrogenase (DPD) is a rate-limiting enzyme that metabolizes 5-fluorouracil (5-FU). We report a patient with metachronous liver metastasis from rectal cancer with low expression of DPD, who demonstrated complete response to chemotherapy comprising 5-FU, Leucovorin, and UFT. A 53-year-old man underwent macroscopically curative proctectomy with coloanal anastomosis for lower rectal cancer (Curability B). The DPD level in the primary tumor determined by an enzyme-linked immunosorbent assay was extremely low (10.3 U/mg.protein). Three months postoperatively, 5-FU (333 mg/m2) + Leucovorin (200 mg/m2) therapy (once a week for 3 weeks with a one-week rest interval, repeatedly) was started as an adjuvant therapy. However, computed tomography demonstrated a solitary liver metastasis 3 cm in size 1 month later. Chemotherapy was continued with dose escalation of 5-FU (500 mg/m2) and with oral administration of UFT-E (400 mg/body, daily). Five months later, computed tomography did not detect the liver metastasis, and this finding was maintained for two months (complete response). This case provides evidence that a low expression of DPD in the primary lesion is related to a favorable response of liver metastasis to 5-FU-based systemic chemotherapy.

  10. Teaching for Change: The Difference, Power, and Discrimination Model

    ERIC Educational Resources Information Center

    Xing, Jun, Ed.; Li, Judith, Ed.; Roper, Larry D., Ed.; Shaw, Susan M., Ed.

    2006-01-01

    Over the past three decades, American higher education has witnessed a shift in demographics which has created a more diverse student body. However, many university campuses remain unsupportive or even hostile to minority faculty and students. This anthology introduces to readers the Difference, Power, and Discrimination (DPD) Program, a…

  11. An evaluation of the effect of age and the peri-parturient period on bone metabolism in dairy cows as measured by serum bone-specific alkaline phosphatase activity and urinary deoxypyridinoline concentration.

    PubMed

    Sato, Reiichiro; Onda, Ken; Kato, Hajime; Ochiai, Hideharu; Kawai, Kazuhiro; Iriki, Tsunenori; Kaneko, Kazuyuki; Yamazaki, Yukio; Wada, Yasunori

    2013-08-01

    Various biochemical markers help to evaluate the state of bone turnover in humans and could be used during the peri-parturient period in dairy cows when calcium (Ca) metabolism changes dramatically. To investigate this, the peri-partum characteristics of serum bone-specific alkaline phosphatase (BAP) and urinary deoxypyridinoline (DPD) were investigated. Both serum BAP activity and urinary DPD concentrations were increased and demonstrated wide variability in younger animals, and these findings were consistent with other bone turnover markers. Around the time of parturition, serum Ca concentration and serum BAP activity in multiparous cows were significantly lower than in primiparous cows, but urinary DPD concentration was unchanged. The use of BAP as a bone formation marker appears to be valuable for evaluating bone remodelling status in cows, but the specificity of the test needs to be confirmed. The DPD/BAP ratio around parturition demonstrated a clear difference in bone turnover status between the two parity groups with multiparous cows demonstrating increased signs of bone resorption compared with primiparous cows, corresponding to the Ca requirement for milk production. In future studies, the applicability of the ratio of bone resorption marker to bone formation marker should be evaluated for bone turnover assessment.

  12. Sensorimotor gating characteristics of violent men with comorbid psychosis and dissocial personality disorder: Relationship with antisocial traits and psychosocial deprivation.

    PubMed

    Sedgwick, Ottilie; Young, Susan; Greer, Ben; Arnold, Jack; Parsons, Aisling; Puzzo, Ignazio; Terracciano, Mariafatima; Das, Mrigendra; Kumari, Veena

    2017-07-06

    Evidence suggests violence amongst those with psychosis is not aetiologically homogeneous, and that a large proportion of those who engage in violent behaviour have a comorbid antisocial personality disorder. Initial investigations indicate that this subgroup has distinct historical and neuropsychological characteristics, which may indicate diverse treatment needs. This study investigated sensorimotor gating characteristics of violent men with diagnoses of both psychosis and dissocial personality disorder (DPD) (n=21) relative to violent men with psychosis alone (n=12), DPD alone (n=14) and healthy, non-violent male controls (n=27), using the prepulse inhibition (PPI) paradigm. The results indicated that, relative to the psychosis alone and healthy control groups, the comorbid group had lower PPI, especially at 60-ms prepulse-to-pulse interval. The DPD group took an intermediary position and did not differ from any group. Antisocial personality traits (factor two scores of the Psychopathy Checklist - Revised), and greater severity of childhood psychosocial deprivation (including physical and sexual abuse), were significantly correlated with poor PPI across the clinical sample. The findings suggest diverse sensorimotor gating profiles amongst subgroups of violent offenders, with comorbid psychosis and DPD showing most impairment. This is consistent with a 'double dose' of deficit explanation amongst those with both diagnoses, explained at least in part by presence of antisocial personality traits and childhood psychosocial deprivation. Copyright © 2017. Published by Elsevier B.V.

  13. Modeling of mesoscopic electrokinetic phenomena using charged dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Deng, Mingge; Li, Zhen; Karniadakis, George

    2015-11-01

    In this work, we propose a charged dissipative particle dynamics (cDPD) model for investigation of mesoscopic electrokinetic phenomena. In particular, this particle-based method was designed to simulate micro- or nano- flows which governing by Poisson-Nernst-Planck (PNP) equation coupled with Navier-Stokes (NS) equation. For cDPD simulations of wall-bounded fluid systems, a methodology for imposing correct Dirichlet and Neumann boundary conditions for both PNP and NS equations is developed. To validate the present cDPD model and the corresponding boundary method, we perform cDPD simulations of electrostatic double layer (EDL) in the vicinity of a charged wall, and the results show good agreement with the mean-field theoretical solutions. The capacity density of a parallel plate capacitor in salt solution is also investigated with different salt concentration. Moreover, we utilize the proposed methodology to study the electroosmotic and electroosmotic/pressure-driven flow in a micro-channel. In the last, we simulate the dilute polyelectrolyte solution both in bulk and micro-channel, which show the flexibility and capability of this method in studying complex fluids. This work was sponsored by the Collaboratory on Mathematics for Mesoscopic Modeling of Materials (CM4) supported by DOE.

  14. Energy-conserving dissipative particle dynamics with temperature-dependent properties

    SciTech Connect

    Li, Zhen; Tang, Yu-Hang; Lei, Huan; Caswell, Bruce; Karniadakis, George E.

    2014-05-01

    The dynamic properties of fluid, including diffusivity and viscosity, are temperature-dependent and can significantly influence the flow dynamics of mesoscopic non-isothermal systems. To capture the correct temperature-dependence of a fluid, an energy-conserving dissipative particle dynamics (eDPD) model is developed by expressing the weighting terms of the dissipative force and the random force as functions of temperature. The diffusivity and viscosity of liquid water at various temperatures ranging from 273 K to 373 K are used as examples for verifying the proposed model. Simulations of a Poiseuille flow and a steady case of heat conduction for reproducing the Fourier law are carried out to validate the present eDPD formulation and the thermal boundary conditions. Results show that the present eDPD model recovers the standard DPD model when isothermal fluid systems are considered. For non-isothermal fluid systems, the present model can predict the diffusivity and viscosity consistent with available experimental data of liquid water at various temperatures. Moreover, an analytical formula for determining the mesoscopic heat friction is proposed. The validity of the formula is confirmed by reproducing the experimental data for Prandtl number of liquid water at various temperatures. The proposed method is demonstrated in water but it can be readily extended to other liquids. (C) 2014 Elsevier Inc. All rights reserved.

  15. Chlorine Analysis - Wastewater. Training Module 5.125.2.77.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with the laboratory procedures for determining the combined chlorine residual of a wastewater sample. Included are objectives, instructor guides, student handouts, and transparency masters. This module considers the amperometric, DPD,…

  16. Conserving the linear momentum in stochastic dynamics: Dissipative particle dynamics as a general strategy to achieve local thermostatization in molecular dynamics simulations.

    PubMed

    Passler, Peter P; Hofer, Thomas S

    2017-02-15

    Stochastic dynamics is a widely employed strategy to achieve local thermostatization in molecular dynamics simulation studies; however, it suffers from an inherent violation of momentum conservation. Although this short-coming has little impact on structural and short-time dynamic properties, it can be shown that dynamics in the long-time limit such as diffusion is strongly dependent on the respective thermostat setting. Application of the methodically similar dissipative particle dynamics (DPD) provides a simple, effective strategy to ensure the advantages of local, stochastic thermostatization while at the same time the linear momentum of the system remains conserved. In this work, the key parameters to employ the DPD thermostats in the framework of periodic boundary conditions are investigated, in particular the dependence of the system properties on the size of the DPD-region as well as the treatment of forces near the cutoff. Structural and dynamical data for light and heavy water as well as a Lennard-Jones fluid have been compared to simulations executed via stochastic dynamics as well as via use of the widely employed Nose-Hoover chain and Berendsen thermostats. It is demonstrated that a small size of the DPD region is sufficient to achieve local thermalization, while at the same time artifacts in the self-diffusion characteristic for stochastic dynamics are eliminated. © 2016 Wiley Periodicals, Inc.

  17. Enzymatic polymerization of high molecular weight DNA amphiphiles that self-assemble into star-like micelles.

    PubMed

    Tang, Lei; Tjong, Vinalia; Li, Nan; Yingling, Yaroslava G; Chilkoti, Ashutosh; Zauscher, Stefan

    2014-05-21

    High molecular weight ssDNA amphiphiles are synthesized by enzymatic polymerization. These highly asymmetric diblock DNA copolymers self-assemble into "hairy", star-like micelles, shown in the AFM image and the DPD snapshot. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Determination of Free Available Chlorine in Denitrified Wastewater Effluent

    DTIC Science & Technology

    1993-01-01

    of chloramines, particularly monochloramine , on the free available chlorine residual measurements made using the DPD method was significant. The...hypochorous acid, hypochlorite ion, and aqueous chlorine, CI.,q)) and combined chlorine ( monochloramine , dichloramine, and nitrogen trichloride) was not...neutral molecule resembling water in structure, it diffuses across cell membranes quite easily. Chloramines, such as monochloramine , are much weaker

  19. Illuminating a neglected clinical issue: societal costs of interpersonal dependency and dependent personality disorder.

    PubMed

    Bornstein, Robert F

    2012-07-01

    To determine the degree to which patients with high levels of trait dependency or dependent personality disorder (DPD) engage in behaviors that harm themselves and others (e.g., domestic violence, child abuse). Six domains of literature were reviewed: (a) dependency as a risk factor for physical illness; (b) health care utilization and expenditures; (c) global and domain-specific functional impairment; (d) violence toward others; (e) victimization by others; and (f) self-harm. High levels of trait dependency and DPD are associated with elevated risk for physical illness, partner and child abuse, and suicidality, as well as with high levels of functional impairment and increased health care expenditure. Contrary to clinical lore, trait dependency and DPD are associated with behaviors that lead to myriad negative consequences for the dependent person, those close to them, and society as a whole. These patterns have noteworthy implications for assessment and treatment of dependent patients and suggest that DPD should be included as a diagnostic category in the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition. © 2012 Wiley Periodicals, Inc.

  20. Functional connectivity comparison of the default mode network in non-depressed Parkinson disease and depressed Parkinson disease

    NASA Astrophysics Data System (ADS)

    Han, Yuan; Li, Rui; Liu, Jiangtao; Yao, Li; Wu, Xia

    2011-03-01

    Examining the spontaneous activity to understand the neural mechanism of brain disorders and establish neuroimaging-based disease-related biomarkers is a focus in recent resting-state functional MRI (fMRI) studies. The present study hypothesized that resting activity in the default mode network (DMN), which was used for characterizing the resting-state human brain might be different in patients with depressed Parkinson disease (dPD) compared with non-depressed Parkinson disease (ndPD) patients. To test the hypothesis, we firstly employed the Group independent component analysis (ICA) approach to isolate the DMN for the two groups by analyzing the resting-state fMRI data from a group of 12 patients with dPD and a group of 12 age-matched ndPD subjects. Between-group comparison of the functional connectivity in the DMN was then performed to examine the impact of depression on the intrinsic activity in PD. We found 1) the core region from the network the medial prefrontal cortex (MPFC) show significant decreased activity in dPD group compared with ndPD group; 2) the activity in MPFC has significant negative correlation with behavioral measure; 3) the resting activity intensity of MPFC is suggested to be a promising biomarker for distinguishing dPD from ndPD.

  1. Douglas-fir displays a range of growth responses to temperature, water, and Swiss needle cast in western Oregon, USA

    EPA Science Inventory

    Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) growth in the Pacific Northwest is affected by climatic, edaphic factors and Swiss needle cast (SNC) disease. We examine Douglas-fir growth responses to temperature, dewpoint deficit (DPD), soil moisture, and SNC ...

  2. Flow in complex domains simulated by Dissipative Particle Dynamics driven by geometry-specific body-forces

    NASA Astrophysics Data System (ADS)

    Yazdani, Alireza; Deng, Mingge; Caswell, Bruce; Karniadakis, George Em

    2016-01-01

    We demonstrate how the quality of simulations by Dissipative Particle Dynamics (DPD) of flows in complex geometries is greatly enhanced when driven by body forces suitably tailored to the geometry. In practice, the body force fields are most conveniently chosen to be the pressure gradient of the corresponding Navier-Stokes (N-S) flow. In the first of three examples, the driving-force required to yield a stagnation-point flow is derived from the pressure field of the potential flow for a lattice of counter-rotating line vortices. Such a lattice contains periodic squares bounded by streamlines with four vortices within them. Hence, the DPD simulation can be performed with periodic boundary conditions to demonstrate the value of a non-uniform driving-force without the need to model real boundaries. The second example is an irregular geometry consisting of a 2D rectangular cavity on one side of an otherwise uniform channel. The Navier-Stokes pressure field for the same geometry is obtained numerically, and its interpolated gradient is then employed as the driving-force for the DPD simulation. Finally, we present a third example, where the proposed method is applied to a complex 3D geometry of an asymmetric constriction. It is shown that in each case the DPD simulations closely reproduce the Navier-Stokes solutions. Convergence rates are found to be much superior to alternative methods; in addition, the range of convergence with respect to Reynolds number and Mach number is greatly extended.

  3. Liquid-liquid equilibria for soft-repulsive particles: improved equation of state and methodology for representing molecules of different sizes and chemistry in dissipative particle dynamics.

    PubMed

    Liyana-Arachchi, Thilanga P; Jamadagni, Sumanth N; Eike, David; Koenig, Peter H; Siepmann, J Ilja

    2015-01-28

    Three developments are presented that significantly expand the applicability of dissipative particle dynamics (DPD) simulations for symmetric and non-symmetric mixtures, where the former contain particles with equal repulsive parameter for self-interactions but a different repulsive parameter for cross-interactions, and the latter contain particles with different repulsive parameters also for the self-interactions. Monte Carlo and molecular dynamics simulations for unary phases covering a wide range of repulsive parameters and of densities for single-bead DPD particles point to deficiencies of the Groot and Warren equation of state (GW-EOS) [J. Chem. Phys. 107, 4423 (1997)]. A revised version, called rGW-EOS, is proposed here that is significantly more accurate over a wider range of parameters/densities. The second development is the generalization of the relationship between the Flory-Huggins χ parameter and the repulsive cross-interaction parameter when the two particles involved have different molecular volumes. The third aspect is an investigation of Gibbs ensemble Monte Carlo simulation protocols, which demonstrates the importance of volume fluctuations and excess volumes of mixing even for equimolar symmetric mixtures of DPD particles. As an illustrative example, the novel DPD methodology is applied to the prediction of the liquid-liquid equilibria for acetic anhydride/(n-hexane or n-octane) binary mixtures.

  4. Teaching for Change: The Difference, Power, and Discrimination Model

    ERIC Educational Resources Information Center

    Xing, Jun, Ed.; Li, Judith, Ed.; Roper, Larry D., Ed.; Shaw, Susan M., Ed.

    2006-01-01

    Over the past three decades, American higher education has witnessed a shift in demographics which has created a more diverse student body. However, many university campuses remain unsupportive or even hostile to minority faculty and students. This anthology introduces to readers the Difference, Power, and Discrimination (DPD) Program, a…

  5. Dissipative particle dynamics for systems with high density of charges: Implementation of electrostatic interactions

    NASA Astrophysics Data System (ADS)

    Gavrilov, A. A.; Chertovich, A. V.; Kramarenko, E. Yu.

    2016-11-01

    In this work, we study the question of how to introduce electrostatic interactions in dissipative particle dynamics (DPD) method in order to correctly reproduce the properties of systems with high density of charges, including those with inhomogeneous charge distribution. To this end, we formulate general requirements for the electrostatic force in DPD and propose a new functional form of the force which suits better for satisfying these requirements than the previously used ones. In order to verify the proposed model, we study the problem of a single polyelectrolyte chain collapse and compare the results with molecular dynamics (MD) simulations in which the exact Coulomb force is used. We show that an excellent quantitative agreement between MD and DPD models is observed if the length parameter D of the proposed electrostatic force is chosen properly; the recommendations concerning the choice of this parameter value are given based on the analysis of a polyelectrolyte chain collapse behavior. Finally, we demonstrate the applicability of DPD with the proposed electrostatic force to studying microphase separation phenomenon in polyelectrolyte melts and show that the same values of D as in the case of single chain collapse should be used, thus indicating universality of the model. Due to the charge correlation attraction, a long-range order in such melts can be observed even at zero Flory-Huggins parameter.

  6. On the connection between dissipative particle dynamics and the Itô-Stratonovich dilemma

    NASA Astrophysics Data System (ADS)

    Farago, Oded; Grønbech-Jensen, Niels

    2016-02-01

    Dissipative Particle Dynamics (DPD) is a popular simulation model for investigating hydrodynamic behavior of systems with non-negligible equilibrium thermal fluctuations. DPD employs soft core repulsive interactions between the system particles, thus allowing them to overlap. This supposedly permits relatively large integration time steps, which is an important feature for simulations on large temporal scales. In practice, however, an increase in the integration time step leads to increasingly larger systematic errors in the sampling statistics. Here, we demonstrate that the prime origin of these systematic errors is the multiplicative nature of the thermal noise term in Langevin's equation, i.e., the fact that it depends on the instantaneous coordinates of the particles. This lead to an ambiguity in the interpretation of the stochastic differential Langevin equation, known as the Itô-Stratonovich dilemma. Based on insights from previous studies of the dilemma, we propose a novel algorithm for DPD simulations exhibiting almost an order of magnitude improvement in accuracy, and nearly twice the efficiency of commonly used DPD Langevin thermostats.

  7. Collaborative Knowledge Building Using the Design Principles Database

    ERIC Educational Resources Information Center

    Kali, Yael

    2006-01-01

    In this study we describe a mechanism for supporting a community of learning scientists who are exploring educational technologies by helping them to share and collaboratively build design knowledge. The Design Principles Database (DPD) is intended to be built and used by this community to provide an infrastructure for participants to publish,…

  8. Coarse-grained explicit solvent simulation of the translational and rotational diffusion of a spherical particle in a polymer solution

    NASA Astrophysics Data System (ADS)

    Pryamitsyn, Victor; Ganesan, Venkat

    We use an extension of DPD model to address the dynamical properties of a colloid particle in an unentangled semi-dilute polymer solution. Solvent and monomers are represented as DPD particles.The colloid particle is represented as a larger DPD particle with the rotational degrees of freedom and tangential component of the dissipative and random DPD interactions with the solvent and monomers. This allows us to model a finite slip length boundary condition at the particle fluid interface and study translational Dt and rotational Dr diffusivities of a spherical particle. For zero polymer concentration our results agree with the Stokes-Einstein (SE) theory. Fore dilute and semi-dilute polymer solutions we have found that polymer dynamic follow the Zimm model in a dilute regime and the Rouse model at high polymer concentration. For particles smaller than the polymer Rg observed Dt is much high than SE prediction for R >Rg SE prediction recovers. We have found that increase of Dr relative to SE is rather correlated to the R/Rg ratio than R/ξ, where ξ is the thickness of a depletion shell around the particle. Dr is very sensitive to the slip length at the particle fluid interface and insensitive to R/Rg.

  9. Consistent model reduction of polymer chains in solution in dissipative particle dynamics: Model description

    NASA Astrophysics Data System (ADS)

    Moreno, Nicolas; Nunes, Suzana P.; Calo, Victor M.

    2015-11-01

    We introduce a framework for model reduction of polymer chain models for dissipative particle dynamics (DPD) simulations, where the properties governing the phase equilibria such as the characteristic size of the chain, compressibility, density, and temperature are preserved. The proposed methodology reduces the number of degrees of freedom required in traditional DPD representations to model equilibrium properties of systems with complex molecules (e.g., linear polymers). Based on geometrical considerations we explicitly account for the correlation between beads in fine-grained DPD models and consistently represent the effect of these correlations in a reduced model, in a practical and simple fashion via power laws and the consistent scaling of the simulation parameters. In order to satisfy the geometrical constraints in the reduced model we introduce bond-angle potentials that account for the changes in the chain free energy after the model reduction. Following this coarse-graining process we represent high molecular weight DPD chains (i.e., ≥ 200 beads per chain) with a significant reduction in the number of particles required (i.e., ≥ 20 times the original system). We show that our methodology has potential applications modeling systems of high molecular weight molecules at large scales, such as diblock copolymer and DNA.

  10. Developing Instructional Leaders: Using Mixed Methods to Explore the Black Box of Planned Change in Principals' Professional Practice

    ERIC Educational Resources Information Center

    Barnes, Carol A.; Camburn, Eric; Sanders, Beth R.; Sebastian, James

    2010-01-01

    Purpose: This study examines learning, and both cognitive and behavioral change among a sample of randomly assigned urban principals, half of whom participated in a sustained, district-based professional development program (DPD). Research Methods: Latent class analyses of daily log data, qualitative typology development, and case studies of…

  11. Depressive Personality Disorder: A Comparison of Three Self-Report Measures

    ERIC Educational Resources Information Center

    Miller, Joshua D.; Tant, Adam; Bagby, R. Michael

    2010-01-01

    Depressive personality disorder (DPD) was included in the appendix of the "Diagnostic and Statistical Manual of Mental Disorders", Fourth Edition ("DSM-IV") for further study. Questions abound regarding this disorder in terms of its distinctiveness from extant diagnostic constructs and clinical significance.This study examines…

  12. Relationship between alexithymia and dependent personality disorder: a dimensional analysis.

    PubMed

    Loas, Gwenolé; Baelde, Olympe; Verrier, Annie

    2015-02-28

    The present study had two aims and used two different samples. The first aim was to determine if alexithymia and dependent personality disorder (DPD) are distinct or overlapping constructs. The second aim was to determine the specificity and the stability of the relationship between alexithymia and DPD. The first study used exploratory principal components analysis (PCA) in a sample of 477 non-clinical subjects who completed three questionnaires measuring alexithymia (Twenty item Toronto Alexithymia Scale, i.e. TAS-20), dependent personality disorder (Dependent Personality Questionnaire, i.e. DPQ) and depression (Beck Depression Inventory-II, i.e. BDI-II). The second study used a sample of 305 subjects consecutively admitted to an outpatient department of legal medicine. The subjects completed (at admission and 3 months later) the Structured Clinical Interview for DSM-IV, screen questionnaire (SCID-II-SQ), the TAS-20 and the BDI. Multiple regressions were done. For the first study, the PCA yielded a four-factor solution with no overlap of the significant factor loadings for the items from each scale and with the factors corresponding to their respective construct. For the second study, multiple regressions showed that only avoidant personality disorder was an independent predictor of the TAS-20 scores. Alexithymia is a construct that is distinct and separate from DPD and depression. Alexithymia is not a stable feature of DPD while it is a core feature of avoidant personality disorder. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Grey matter alterations in patients with depersonalization disorder: a voxel-based morphometry study

    PubMed Central

    Daniels, Judith K.; Gaebler, Michael; Lamke, Jan-Peter; Walter, Henrik

    2015-01-01

    Background To our knowledge, no whole brain investigation of morphological aberrations in dissociative disorder is available to date. Previous region-of-interest studies focused exclusively on amygdalar, hippocampal and parahippocampal grey matter volumes and did not include patients with depersonalization disorder (DPD). We therefore carried out an explorative whole brain study on structural brain aberrations in patients with DPD. Methods We acquired whole brain, structural MRI data for patients with DPD and healthy controls. Voxel-based morphometry was carried out to test for group differences, and correlations with symptom severity scores were computed for grey matter volume. Results Our study included 25 patients with DPD and 23 controls. Patients exhibited volume reductions in the right caudate, right thalamus and right cuneus as well as volume increases in the left dorsomedial prefrontal cortex and right somatosensory region that are not a direct function of anxiety or depression symptoms. Limitations To ensure ecological validity, we included patients with comorbid disorders and patients taking psychotropic medication. Conclusion The results of this first whole brain investigation of grey matter volume in patients with a dissociative disorder indentified structural alterations in regions subserving the emergence of conscious perception. It remains unknown if these alterations are best understood as risk factors for or results of the disorder. PMID:25285875

  14. Dissipative particle dynamics with an effective pair potential from integral equation theory of molecular liquids.

    PubMed

    Kobryn, Alexander E; Nikolić, Dragan; Lyubimova, Olga; Gusarov, Sergey; Kovalenko, Andriy

    2014-10-16

    We present a method of DPD simulation based on a coarse-grained effective pair potential obtained from the DRISM-KH molecular theory of solvation. The theory is first used to calculate the radial distribution functions of all-atom solute monomers in all-atom solvent and then to invert them into an effective pair potential between coarse-grained beads such that their fluid without solvent accounts for molecular specificities and solvation effects in the all-atom system. Bonded interactions are sampled in relatively short MD of the all-atom system and modeled with best multi-Gaussian fit. Replacing the heuristically defined conservative force potential in DPD, the coarse-grained effective pair potential is free from the artificial restrictions on potential range and shape and on equal volume of solute and solvent blobs inherent in standard DPD. The procedure is flexible in specifying coarse-grained mapping and enormously increases computational efficiency by eliminating solvent. The method is validated on polystyrene chains of various length in toluene at finite concentrations for room and polystyrene glass transition temperature. It yields the chain elastic properties and diffusion coefficient in good agreement with experiment and all-atom MD simulations. DPD with coarse-grained effective pair potential is capable of predicting both structural and dynamic properties of polymer solutions and soft matter with high accuracy and computational efficiency.

  15. Building a Distributed Product Description for the Joint Strike Fighter

    DTIC Science & Technology

    2001-05-15

    Jim Hollenbach Simulation Strategies , Inc. DPD Project Coordinator Building a Distributed Product Description for the Joint Strike Fighter... Strategies , Inc. Performing Organization Report Number Sponsoring/Monitoring Agency Name(s) and Address(es) NDIA (National Defense Industrial...Approved for public release; distribution is unlimited. JSF SBA Strategy for EMD • Fall 2001: Down-select to one Weapon System Contractor, enter

  16. Investigation of broadband digital predistortion for broadband radio over fiber transmission systems

    NASA Astrophysics Data System (ADS)

    Zhang, Xiupu; Liu, Taijun; Shen, Dongya

    2016-12-01

    In future broadband cloud radio access networks (C-RAN), front-haul transmission systems play a significant role in performance and cost of C-RAN. Broadband and high linearity radio over fiber (RoF) transmission systems are considered a promising solution for the front-haul. Digital linearization is one possible solution for RoF front-haul. In this paper, we investigate RF domain digital predistortion (DPD) linearization for broadband RoF front-haul. The implemented DPD is first investigated in 2.4 GHz WiFi over fiber transmission systems at 36 Mb/s, and more than 8-dB and 5.6-dB improvements of error vector magnitude (EVM) are achieved in back to back (BTB) and after 10 km single mode fiber (SMF) transmission. Further, both WiFi and ultra wide band (UWB) wireless signals are transmitted together, in which the DPD has linearization bandwidth of 2.4 GHz. It is shown that the implemented DPD leads to EVM improvements of 4.5-dB (BTB) and 3.1-dB (10 km SMF) for the WiFi signal, and 4.6-dB (BTB) and 4-dB (10 km SMF) for the broadband UWB signal.

  17. Accelerating Calculations of Reaction Dissipative Particle Dynamics in LAMMPS

    DTIC Science & Technology

    2017-05-17

    reaction kinetics to GPUs and investigating different matrix representations for the stoichiometric matrices in Eqs. 1 and 2. Finally, we summarize the...used for the stoichiometric matrices in Eqs. 1 and 2. 3. Analysis 3.1 Performance and Strong Scaling of Baseline DPD-RX The performance on Thunder

  18. Douglas-fir displays a range of growth responses to temperature, water, and Swiss needle cast in western Oregon, USA

    EPA Science Inventory

    Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) growth in the Pacific Northwest is affected by climatic, edaphic factors and Swiss needle cast (SNC) disease. We examine Douglas-fir growth responses to temperature, dewpoint deficit (DPD), soil moisture, and SNC ...

  19. Lingual kinematics during rapid syllable repetition in Parkinson's disease.

    PubMed

    Wong, Min Ney; Murdoch, Bruce E; Whelan, Brooke-Mai

    2012-01-01

    Rapid syllable repetition tasks are commonly used in the assessment of motor speech disorders. However, little is known about the articulatory kinematics during rapid syllable repetition in individuals with Parkinson's disease (PD). To investigate and compare lingual kinematics during rapid syllable repetition in dysarthric speakers with PD (DPD), non-dysarthric speakers with PD (NDPD) and a group of healthy controls. Electromagnetic articulography was used to record tongue-tip and tongue-back movement in five DPD and five NDPD participants during rapid repetition of /ta/and /ka/syllables, and matched with six healthy controls. Results revealed significant between-group differences for most of the kinematic parameters measured but comparable rapid syllable repetition rates. Post-hoc analyses indicated that the DPD participants, when compared with the NDPD participants, had similar range but prolonged duration of lingual movement. The DPD and NDPD participants had primarily increased range and prolonged duration of lingual movement accompanied by increased speed parameters, when compared with healthy controls. The findings of the present study contradict theories that suggest that the clinical features of hypokinetic dysarthria, including articulatory imprecision, are the outcome of restrictions in the range of movement of the muscles of the articulators. The observed prolonged duration of lingual movement in PD may plausibly be due to the observed increased range of lingual movement rather than slowness of lingual movement. © 2012 Royal College of Speech and Language Therapists.

  20. Assessment of dependency by the FFDI: Comparisons to the PID-5 and maladaptive agreeableness.

    PubMed

    Gore, Whitney L; Widiger, Thomas A

    2015-11-01

    The present study explores the validity of the Five Factor Dependency Inventory (FFDI), a measure of dependent personality traits from the perspective of the five factor model, examined across three separate samples and two studies. The first study examined the FFDI with respect to the traits assigned to assess dependent personality disorder (DPD) by the DSM-5 work group, two measures of DSM-IV-TR DPD and three measures of dependent traits, sampling 184 Mechanical Turk participants and 83 students (the latter oversampled for DPD features). Based on responses from an additional 137 students, the second study investigated the role of maladaptive agreeableness in dependency by examining the FFDI in relation to the interpersonal circumplex using three alternative measures. Discriminant validity was provided with respect to DSM-5 traits and the interpersonal circumplex. Incremental validity was provided with respect to the ability of the FFDI to account for variance within DPD measures beyond the variance explained by DSM-5 traits. Implications for the assessment of dependency and the proposed DSM-5 dimensional trait model are discussed. Copyright © 2015 John Wiley & Sons, Ltd.

  1. Nonsimultaneous chains and dominos in kidney- paired donation-revisited.

    PubMed

    Ashlagi, I; Gilchrist, D S; Roth, A E; Rees, M A

    2011-05-01

    Since 2008, kidney exchange in America has grown in part from the incorporation of nondirected donors in transplant chains rather than simple exchanges. It is controversial whether these chains should be performed simultaneously 'domino-paired donation', (DPD) or nonsimultaneously 'nonsimultaneous extended altruistic donor, chains (NEAD). NEAD chains create 'bridge donors' whose incompatible recipients receive kidneys before the bridge donor donates, and so risk reneging by bridge donors, but offer the opportunity to create more transplants by overcoming logistical barriers inherent in simultaneous chains. Gentry et al. simulated whether DPD or NEAD chains would produce more transplants when chain segment length was limited to three transplants, and reported that DPD performed at least as well as NEAD chains. As this finding contrasts with the experience of several groups involved in kidney-paired donation, we performed simulations that allowed for longer chain segments and used actual patient data from the Alliance for Paired Donation. When chain segments of 4-6 transplants are allowed in the simulations, NEAD chains produce more transplants than DPD. Our simulations showed not only more transplants as chain length increased, but also that NEAD chains produced more transplants for highly sensitized and blood type O recipients.

  2. Dissipative Particle Dynamics simulation of colloidal suspensions

    NASA Astrophysics Data System (ADS)

    Jamali, Safa; Boromand, Arman; Maia, Joao

    2014-03-01

    DPD as a mesoscale method was firstly proposed to study dynamics of suspensions under flow condition. However the proposed method failed to capture shear properties of suspensions because it lacked: first a potential to reproduce lubrication forces and second a clear definition for the colloid surface. Recently we reported a modified DPD method which defines colloidal particles as particles with hard core and a dissipative coat. An additional lubrication force was introduced to include the short-range hydrodynamics that are not captured in original DPD. The model was found to be able to reproduce shear properties of suspensions for a wide range of different systems, from monodisperse to bimodal with different volume fractions, compositions and size ratios. In present work our modified DPD method is employed to study both equilibrium and flow properties of colloidal suspension. Zero shear viscosity of suspension is measured using Green-Kubo expressions and the results are compared to theoretical predictions. Furthermore, structure formation in suspensions is studied in respect to energy landscape of the fluid both at rest and under flow.

  3. Noninvasive markers of bone metabolism in the rhesus monkey: normal effects of age and gender

    NASA Technical Reports Server (NTRS)

    Cahoon, S.; Boden, S. D.; Gould, K. G.; Vailas, A. C.

    1996-01-01

    Measurement of bone turnover in conditions such as osteoporosis has been limited by the need for invasive iliac bone biopsy to reliably determine parameters of bone metabolism. Recent advances in the area of serum and urinary markers of bone metabolism have raised the possibility for noninvasive measurements; however, little nonhuman primate data exist for these parameters. The purpose of this experiment was to define the normal range and variability of several of the newer noninvasive bone markers which are currently under investigation in humans. The primary intent was to determine age and gender variability, as well as provide some normative data for future experiments in nonhuman primates. Twenty-four rhesus macaques were divided into equal groups of male and female according to the following age groupings: 3 years, 5-10 years, 15-20 years, and > 25 years. Urine was collected three times daily for a four-day period and measured for several markers of bone turnoverm including pyridinoline (PYD), deoxypyrodinoline (DPD), hydroxyproline, and creatinine. Bone mineral density measurements of the lumbar spine were performed at the beginning and end of the study period. Serum was also obtained at the time of bone densitometry for measurement of osteocalcin levels by radioimmunoassay. There were no significant differences in bone mineral density, urine PYD, or urine DPD based on gender. Bone density was lowest in the youngest animals, peaked in the 15-20-year group, but again decreased in the oldest animals. The osteocalcin, PYD, and DPD levels followed an inversely related pattern to bone density. The most important result was the relative age insensitivity of the ratio of PYD:DPD in monkeys up to age 20 years. Since bone density changes take months or years to become measurable and iliac biopsies are invasive, the PYD/DPD marker ratio may have important implications for rapid noninvasive measurement of the effects of potential treatments for osteoporosis in the non

  4. Structural, spectroscopic, and reactivity comparison of xanthene- and dibenzofuran-bridged cofacial bisporphyrins.

    PubMed

    Chang, Christopher J; Baker, Erin A; Pistorio, Bradford J; Deng, Yongqi; Loh, Zhi-Heng; Miller, Scott E; Carpenter, Scott D; Nocera, Daniel G

    2002-06-17

    A comparison of the structure, spectroscopy, and oxygen atom-transfer reactivity of cofacial bisporphyrins anchored by xanthene (DPX) and dibenzofuran (DPD) pillars is presented. The synthesis and characterization of dicopper(II) and dinickel(II) complexes of DPD completes a homologous series of homobimetallic zinc(II), copper(II), and nickel(II) complexes for both cofacial platforms. X-ray crystallographic analysis of the parent free-base porphyrins H(4)DPX (1) and H(4)DPD (5) confirms the face-to-face arrangement of the two porphyrin macrocycles with a large available range of vertical pocket sizes: 1 (C(80)H(92)Cl(2)N(8)O), triclinic, space group P1 macro, a = 13.5167(12) A, b = 21.7008(18) A, c = 23.808(2) A, alpha = 80.116(2) degrees, beta = 76.832(2) degrees, gamma = 80.4070(10) degrees, Z = 4; 5 (C(80)H(83)N(8)O(2)), monoclinic, space group C2/c, a = 22.666(2) A, b = 13.6749(14) A, c = 42.084(4) A, beta = 94.554(2) degrees, Z = 8. EPR spectroscopy of dicopper(II) derivatives Cu(2)DPX (3) and Cu(2)DPD (7) complements the crystallographic studies by probing intramolecular metal-metal arrangements in frozen solution. Exciton interactions between the porphyrin subunits in fluid solution are revealed by steady-state and time-resolved electronic absorption and emission spectroscopy. The resulting compilation of structural and spectroscopic data provides a benchmark for the use of these and related platforms for the activation of small-molecule substrates. A structure-function relation is developed for the photoinduced oxygen atom-transfer reactions of bisiron(III) mu-oxo derivatives of DPX and DPD. The efficiency of the photochemical process is markedly dependent (approximately 10(4)-fold) on the vertical flexibility of cofacial architecture provided by the spacer.

  5. Homogenization of global radiosonde humidity data

    NASA Astrophysics Data System (ADS)

    Blaschek, Michael; Haimberger, Leopold

    2016-04-01

    The global radiosonde network is an important source of upper-air measurements and is strongly connected to reanalysis efforts of the 20th century. However, measurements are strongly affected by changes in the observing system and require a homogenization before they can be considered useful in climate studies. In particular humidity measurements are known to show spurious trends and biases induced by many sources, e.g. reporting practices or freezing of the sensor. We propose to detect and correct these biases in an automated way, as has been done with temperature and winds. We detect breakpoints in dew point depression (DPD) time series by employing a standard normal homogeneity test (SNHT) on DPD-departures from ERA-Interim. In a next step, we calculate quantile departures between the latter and the earlier part near the breakpoints of the time series, going back in time. These departures adjust the earlier distribution of DPD to the latter distribution, called quantile matching, thus removing for example a non climatic shift. We employ this approach to the existing radiosonde network. In a first step to verify our approach we compare our results with ERA-Interim data and brightness temperatures of humidity-sensitive channels of microwave measuring radiometers (SSMIS) onboard DMSP F16. The results show that some of the biases can be detected and corrected in an automated way, however large biases that impact the distribution of DPD values originating from known reporting practices (e.g. 30 DPD on US stations) remain. These biases can be removed but not corrected. The comparison of brightness temperatures from satellite and radiosondes proofs to be difficult as large differences result from for example representative errors.

  6. Testing a Neurobiological Model of Depersonalization Disorder Using Repetitive Transcranial Magnetic Stimulation☆

    PubMed Central

    Jay, Emma-Louise; Sierra, Mauricio; Van den Eynde, Frederique; Rothwell, John C.; David, Anthony S.

    2014-01-01

    Background Depersonalization disorder (DPD) includes changes in subjective experiencing of self, encompassing emotional numbing. Functional magnetic resonance imaging (fMRI) has pointed to ventrolateral prefrontal cortex (VLPFC) inhibition of insula as a neurocognitive correlate of the disorder. Objective We hypothesized that inhibition to right VLPFC using repetitive transcranial magnetic stimulation (rTMS) would lead to increased arousal and reduced symptoms. Methods Patients with medication-resistant DSM-IV DPD (N = 17) and controls (N = 20) were randomized to receive one session of right-sided rTMS to VLPFC or temporo-parietal junction (TPJ). 1Hz rTMS was guided using neuronavigation and delivered for 15 min. Co-primary outcomes were: (a) maximum skin conductance capacity, and (b) reduction in depersonalization symptoms (Cambridge Depersonalisation Scale (CDS) [state version]). Secondary outcomes included spontaneous fluctuations (SFs) and event-related skin conductance responses. Results In patients with DPD, rTMS to VLPFC led to increased electrodermal capacity, namely maximum skin conductance deflections. Patients but not controls also showed increased SFs post rTMS. Patients who had either VLPFC or TPJ rTMS showed a similar significant reduction in symptoms. Event-related electrodermal activity did not change. Conclusions A single session of right-sided rTMS to VLPFC (but not TPJ) significantly increased physiological arousal capacity supporting our model regarding the relevance of increased VLPFC activity to emotional numbing in DPD. rTMS to both sites led to reduced depersonalization scores but since this was independent of physiological arousal, this may be a non-specific effect. TMS is a potential therapeutic option for DPD; modulation of VLPFC, if replicated, is a plausible mechanism. PMID:24439959

  7. Comparative analysis of Debrecen sunspot catalogues

    NASA Astrophysics Data System (ADS)

    Győri, L.; Ludmány, A.; Baranyi, T.

    2017-02-01

    Sunspot area data are important for studying solar activity and its long-term variations. At the Debrecen Heliophysical Observatory, we compiled three sunspot catalogues: the Debrecen Photoheliographic Data (DPD), the SDO/HMI Debrecen Data (HMIDD) and the SOHO/MDI Debrecen Data. For comparison, we also compiled an additional sunspot catalogue, the Greenwich Photoheliographic Data, from the digitized Royal Greenwich Observatory images for 1974-76. By comparing these catalogues when they overlap in time, we can investigate how various factors influence the measured area of sunspots, and, in addition, we can derive area cross-calibration factors for these catalogues. The main findings are as follows. Poorer seeing increases the individual corrected spot areas and decreases the number of small spots. Interestingly, the net result of these two effects for the total corrected spot area is zero. DPD daily total corrected sunspot areas are 5 per cent smaller than the HMIDD ones. Revised DPD daily total corrected umbra areas are 9 per cent smaller than those of HMIDD. The Greenwich photoheliographic areas are only a few per cent smaller than DPD areas. A 0.2° difference between the north directions of the DPD and MDI images is found. This value is nearly the same as was found (0.22°) by us in a previous paper comparing HMI and MDI images. The area measurement practice (spots smaller than 10 mh were not directly measured but an area of 2 mh was assigned to each) of the Solar Observing Optical Network cannot explain the large area deficit of the Solar Observing Optical Network.

  8. Interoceptive–reflective regions differentiate alexithymia traits in depersonalization disorder

    PubMed Central

    Lemche, Erwin; Brammer, Michael J.; David, Anthony S.; Surguladze, Simon A.; Phillips, Mary L.; Sierra, Mauricio; Williams, Steven C.R.; Giampietro, Vincent P.

    2013-01-01

    It is unclear to what degree depersonalization disorder (DPD) and alexithymia share abnormal brain mechanisms of emotional dysregulation. We compared cerebral processing of facial expressions of emotion in individuals with DPD to normal controls (NC). We presented happy and sad emotion expressions in increasing intensities from neutral (0%) through mild (50%) to intense (100%) to DPD and non-referred NC subjects in an implicit event-related fMRI design, and correlated respective brain activations with responses on the 20-item Toronto Alexithymia Scale (TAS-20) and its three subscales F1-F3. The TAS-20 predicts clinical diagnosis of DPD with a unique variance proportion of 38%. Differential regression analysis was utilized to ascertain brain regions for each alexithymia subscale. Differential regions of total alexithymia severity for happy emotion were the globus pallidus externus; for identifying feelings (TAS-20 F1 subscale), the right anterior insula; for description of feelings (F2), the right dorsal mid-anterior cingulate gyrus (BA 24); and for externally oriented cognitive style (F3), the left paracingulate gyrus (BA 32). For sad emotion, the differential region for the total TAS-20 score was the dorsal anterior cingulate gyrus (BA 24); for TAS-20 F1, the left inferior anterior insula; for TAS-20 F2, the right PCC (BA 31); and for TAS-20 F3, the right orbital gyrus (BA 10). Supporting our hypotheses, the ascertained brain regions for TAS-20 subscales subserve interoception, monitoring and reflection of internal states and emotion. The presented analyses provide evidence that alexithymia plays a substantial role in emotional dysregulation in DPD, presumably based on restrictions in interoception. PMID:23932225

  9. Microsatellite instability in colorectal cancer and association with thymidylate synthase and dihydropyrimidine dehydrogenase expression

    PubMed Central

    2009-01-01

    Background Microsatellite instability (MSI) refers to mutations in short motifs of tandemly repeated nucleotides resulting from replication errors and deficient mismatch repair (MMR). Colorectal cancer with MSI has characteristic biology and chemosensitivity, however the molecular basis remains unclarified. The association of MSI and MMR status with outcome and with thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) expression in colorectal cancer were evaluated. Methods MSI in five reference loci, MMR enzymes (hMSH2, hMSH6, hMLH1 and hPMS2), thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) expression were assessed in paraffin embedded tumor specimens, and associated with outcome in 340 consecutive patients completely resected for colorectal cancer stages II-IV and subsequently receiving adjuvant 5-fluorouracil therapy. Results MSI was found in 43 (13.8%) tumors. Absence of repair protein expression was assessed in 52 (17.0%) tumors, which had primarily lost hMLH1 in 39 (12.7%), hMSH2 in 5 (1.6%), and hMSH6 in 8 (2.6%) tumors. In multivariate analysis MSI (instable) compared to MSS (stable) tumors were significantly associated with lower risk of recurrence (hazard ratio (HR) = 0.3; 95% CI: 0.2–0.7; P = 0.0007) and death (HR = 0.4; 95% CI: 0.2–0.9; P = 0.02) independently of the TS and DPD expressions. A direct relationship between MSI and TS intensity (P = 0.001) was found, while there was no significant association with DPD intensity (P = 0.1). Conclusion The favourable outcome of MSI colorectal carcinomas is ascribed mainly to the tumor biology and to a lesser extent to antitumor response to 5-fluorouracil therapy. There is no evidence that differential TS or DPD expression may account for these outcome characteristics. PMID:19154585

  10. Electrostatics in dissipative particle dynamics using Ewald sums with point charges

    NASA Astrophysics Data System (ADS)

    Terrón-Mejía, Ketzasmin A.; López-Rendón, Roberto; Gama Goicochea, Armando

    2016-10-01

    A proper treatment of electrostatic interactions is crucial for the accurate calculation of forces in computer simulations. Electrostatic interactions are typically modeled using Ewald-based methods, which have become some of the cornerstones upon which many other methods for the numerical computation of electrostatic interactions are based. However, their use with charge distributions rather than point charges requires the inclusion of ansatz for the solutions of the Poisson equation, since there is no exact solution known for smeared out charges. The interest in incorporating electrostatic interactions at the scales of length and time that are relevant for the study the physics of soft condensed matter has increased considerably. Using mesoscale simulation techniques, such as dissipative particle dynamics (DPD), allows us to reach longer time scales in numerical simulations, without abandoning the particulate description of the problem. The main problem with incorporating electrostatics into DPD simulations is that DPD particles are soft and those particles with opposite charge can form artificial clusters of ions. Here we show that one can incorporate the electrostatic interactions through Ewald sums with point charges in DPD if larger values of coarse-graining degree are used, where DPD is truly mesoscopic. Using point charges with larger excluded volume interactions, the artificial formation of ionic pairs with point charges can be avoided and one obtains correct predictions. We establish ranges of parameters useful for detecting boundaries where artificial formation of ionic pairs occurs. Lastly, using point charges we predict the scaling properties of polyelectrolytes in solvents of varying quality, and obtain predictions that are in agreement with calculations that use other methods and with recent experimental results.

  11. A multiple time stepping algorithm for efficient multiscale modeling of platelets flowing in blood plasma

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Zhang, Na; Deng, Yuefan; Bluestein, Danny

    2015-03-01

    We developed a multiple time-stepping (MTS) algorithm for multiscale modeling of the dynamics of platelets flowing in viscous blood plasma. This MTS algorithm improves considerably the computational efficiency without significant loss of accuracy. This study of the dynamic properties of flowing platelets employs a combination of the dissipative particle dynamics (DPD) and the coarse-grained molecular dynamics (CGMD) methods to describe the dynamic microstructures of deformable platelets in response to extracellular flow-induced stresses. The disparate spatial scales between the two methods are handled by a hybrid force field interface. However, the disparity in temporal scales between the DPD and CGMD that requires time stepping at microseconds and nanoseconds respectively, represents a computational challenge that may become prohibitive. Classical MTS algorithms manage to improve computing efficiency by multi-stepping within DPD or CGMD for up to one order of magnitude of scale differential. In order to handle 3-4 orders of magnitude disparity in the temporal scales between DPD and CGMD, we introduce a new MTS scheme hybridizing DPD and CGMD by utilizing four different time stepping sizes. We advance the fluid system at the largest time step, the fluid-platelet interface at a middle timestep size, and the nonbonded and bonded potentials of the platelet structural system at two smallest timestep sizes. Additionally, we introduce parameters to study the relationship of accuracy versus computational complexities. The numerical experiments demonstrated 3000x reduction in computing time over standard MTS methods for solving the multiscale model. This MTS algorithm establishes a computationally feasible approach for solving a particle-based system at multiple scales for performing efficient multiscale simulations.

  12. A Multiple Time Stepping Algorithm for Efficient Multiscale Modeling of Platelets Flowing in Blood Plasma.

    PubMed

    Zhang, Peng; Zhang, Na; Deng, Yuefan; Bluestein, Danny

    2015-03-01

    We developed a multiple time-stepping (MTS) algorithm for multiscale modeling of the dynamics of platelets flowing in viscous blood plasma. This MTS algorithm improves considerably the computational efficiency without significant loss of accuracy. This study of the dynamic properties of flowing platelets employs a combination of the dissipative particle dynamics (DPD) and the coarse-grained molecular dynamics (CGMD) methods to describe the dynamic microstructures of deformable platelets in response to extracellular flow-induced stresses. The disparate spatial scales between the two methods are handled by a hybrid force field interface. However, the disparity in temporal scales between the DPD and CGMD that requires time stepping at microseconds and nanoseconds respectively, represents a computational challenge that may become prohibitive. Classical MTS algorithms manage to improve computing efficiency by multi-stepping within DPD or CGMD for up to one order of magnitude of scale differential. In order to handle 3-4 orders of magnitude disparity in the temporal scales between DPD and CGMD, we introduce a new MTS scheme hybridizing DPD and CGMD by utilizing four different time stepping sizes. We advance the fluid system at the largest time step, the fluid-platelet interface at a middle timestep size, and the nonbonded and bonded potentials of the platelet structural system at two smallest timestep sizes. Additionally, we introduce parameters to study the relationship of accuracy versus computational complexities. The numerical experiments demonstrated 3000x reduction in computing time over standard MTS methods for solving the multiscale model. This MTS algorithm establishes a computationally feasible approach for solving a particle-based system at multiple scales for performing efficient multiscale simulations.

  13. A Multiple Time Stepping Algorithm for Efficient Multiscale Modeling of Platelets Flowing in Blood Plasma

    PubMed Central

    Zhang, Peng; Zhang, Na; Deng, Yuefan; Bluestein, Danny

    2015-01-01

    We developed a multiple time-stepping (MTS) algorithm for multiscale modeling of the dynamics of platelets flowing in viscous blood plasma. This MTS algorithm improves considerably the computational efficiency without significant loss of accuracy. This study of the dynamic properties of flowing platelets employs a combination of the dissipative particle dynamics (DPD) and the coarse-grained molecular dynamics (CGMD) methods to describe the dynamic microstructures of deformable platelets in response to extracellular flow-induced stresses. The disparate spatial scales between the two methods are handled by a hybrid force field interface. However, the disparity in temporal scales between the DPD and CGMD that requires time stepping at microseconds and nanoseconds respectively, represents a computational challenge that may become prohibitive. Classical MTS algorithms manage to improve computing efficiency by multi-stepping within DPD or CGMD for up to one order of magnitude of scale differential. In order to handle 3–4 orders of magnitude disparity in the temporal scales between DPD and CGMD, we introduce a new MTS scheme hybridizing DPD and CGMD by utilizing four different time stepping sizes. We advance the fluid system at the largest time step, the fluid-platelet interface at a middle timestep size, and the nonbonded and bonded potentials of the platelet structural system at two smallest timestep sizes. Additionally, we introduce parameters to study the relationship of accuracy versus computational complexities. The numerical experiments demonstrated 3000x reduction in computing time over standard MTS methods for solving the multiscale model. This MTS algorithm establishes a computationally feasible approach for solving a particle-based system at multiple scales for performing efficient multiscale simulations. PMID:25641983

  14. Noninvasive markers of bone metabolism in the rhesus monkey: normal effects of age and gender

    NASA Technical Reports Server (NTRS)

    Cahoon, S.; Boden, S. D.; Gould, K. G.; Vailas, A. C.

    1996-01-01

    Measurement of bone turnover in conditions such as osteoporosis has been limited by the need for invasive iliac bone biopsy to reliably determine parameters of bone metabolism. Recent advances in the area of serum and urinary markers of bone metabolism have raised the possibility for noninvasive measurements; however, little nonhuman primate data exist for these parameters. The purpose of this experiment was to define the normal range and variability of several of the newer noninvasive bone markers which are currently under investigation in humans. The primary intent was to determine age and gender variability, as well as provide some normative data for future experiments in nonhuman primates. Twenty-four rhesus macaques were divided into equal groups of male and female according to the following age groupings: 3 years, 5-10 years, 15-20 years, and > 25 years. Urine was collected three times daily for a four-day period and measured for several markers of bone turnoverm including pyridinoline (PYD), deoxypyrodinoline (DPD), hydroxyproline, and creatinine. Bone mineral density measurements of the lumbar spine were performed at the beginning and end of the study period. Serum was also obtained at the time of bone densitometry for measurement of osteocalcin levels by radioimmunoassay. There were no significant differences in bone mineral density, urine PYD, or urine DPD based on gender. Bone density was lowest in the youngest animals, peaked in the 15-20-year group, but again decreased in the oldest animals. The osteocalcin, PYD, and DPD levels followed an inversely related pattern to bone density. The most important result was the relative age insensitivity of the ratio of PYD:DPD in monkeys up to age 20 years. Since bone density changes take months or years to become measurable and iliac biopsies are invasive, the PYD/DPD marker ratio may have important implications for rapid noninvasive measurement of the effects of potential treatments for osteoporosis in the non

  15. Innovative Procedure for the, in Situ, Measurement of the Resistive Thermal Coefficient of H(D)/Pd during Electrolysis:. Cross-Comparison of New Elements Detected in the Th-Hg-Pd-D(H) Electrolytic Cells

    NASA Astrophysics Data System (ADS)

    Celani, Francesco; Spallone, A.; Righi, E.; Trenta, G.; Catena, C.; D'Agostaro, G.; Quercia, P.; Andreassi, V.; Marini, P.; di Stefano, V.; Nakamura, M.; Mancini, A.; Sona, P. G.; Fontana, F.; Gamberale, L.; Garbelli, D.; Celia, E.; Falcioni, F.; Marchesini, M.; Novaro, E.; Mastromatteo, U.

    2006-02-01

    In the framework of cold fusion studies one of the most important parameters is the deuterium (D) to palladium (Pd) ratio, D/Pd. It is well known that the value of this parameter is related to the normalised resistivity (R/R0) of the D-Pd system. When at high D/Pd ratios (i.e. at low R/R0 values) some excess heat occurs, the Pd wire temperature increase and, as a consequence, the apparent R/R0 value also increases. This effect might give raise to ambiguous data interpretation: similar results are in fact expected in case of a Pd wire degassing (i.e. decreasing of D/Pd ratio). To solve this problem, we developed an innovative procedure and a suitable experimental set-up for the in situ measurement of the Resistive Temperature Coefficient (which is affected only by the real D/Pd ratio) during electrolysis. We will report the results on the hydrogen and deuterium loading of thin (50 μm), and long (60cm) Pd wires, immersed in a solution of C2H5OD (or C2H5OH) and D2O (or H2O), with addition of thorium (Th) and mercury (Hg) salts at micromolar concentrations. Evidence of "transmutations" of some elements occasionally present on the Pd surface, and sometimes also in the electrolytic solution, have often been claimed in cold fusion experiments. In the present work, unexpected elements have been detected by high-resolution ICP-MS analysis. Some of these elements have also an isotopic composition different from the natural one.

  16. Accelerated bone turnover identifies hemiplegic patients at higher risk of demineralization.

    PubMed

    Del Puente, A; Pappone, N; Servodio Iammarrone, C; Esposito, A; Scarpa, R; Costa, L; Caso, F; Bardoscia, A; Del Puente, A

    2016-01-01

    Immobilization osteoporosis represents a severe complication in hemiplegic patients (HPs), causing fragility fractures, which may occur during rehabilitation reducing functional recovery and survival. The aim of the study was to investigate determinants of bone loss, independent from length of immobilization, which may be useful in early identification of HPs at higher risk of demineralization. Forty-eight HPs of both sexes underwent anthropometric measurements, evaluation of scores of spasticity and of lower limb motory capacity. Laboratory tests were performed. On serum: calcium; phosphorus; creatinine; ALP; iPTH; 25(OH) vitamin-D; sex hormones; Δ4-androstenedione; DHEA-S; insulin; IGF-1; FT3; FT4; TSH; c-AMP. On urine: c-AMP and calcium/creatinine ratio. Two bone turnover markers were measured: serum osteocalcin (BGP) and urinary deoxypyridinoline (DPD). Bone mineral density was determined at both femoral necks, defining a percentage difference in bone loss between paretic and non-paretic limb, thus controlling for the complex cofactors involved. Only bone turnover markers significantly and directly correlated with the entity of demineralization, controlling for age, sex and length of immobilization in the multivariate analysis (BGP coefficient estimate=0.008; SE=0.003; p=0.020; DPD coefficient estimate=0.005; SE=0.002; p=0.036). BGP and DPD are not dependent on anthropometric and endocrine-metabolic parameters, disability patterns and duration of immobilization, thus represent independent determinants of the degree of demineralization. A cutoff was defined for BGP and DPD above which subjects show significantly greater risk of demineralization. The immobilization event generates more severe bone loss when it occurs in subjects with higher bone turnover. BGP and DPD measurements may be of primary importance for early identification of HPs at risk, with relevant preventive implications.

  17. Detection of low-molecular-mass plasma peptides in the cavernous and systemic blood of healthy men during penile flaccidity and rigidity--an experimental approach using the novel differential peptide display technology.

    PubMed

    Tammen, Harald; Hess, Rüdiger; Uckert, Stefan; Becker, Armin J; Stief, Christian G; Knappe, Peter Schulz; Schrader, Michael; Jonas, Udo

    2002-05-01

    To use Differential Peptide Display (DPD) technology to evaluate the patterns of low-molecular-mass peptides and small proteins in the systemic and cavernous blood taken from healthy adult male volunteers during the penile stages of flaccidity and rigidity. Results from basic research implicate a role of various peptides in the control of mammalian penile erectile tissue. Nevertheless, it is not yet known which particular peptides are essential in the regulation of penile flaccidity, tumescence, rigidity, and detumescence. Five healthy male subjects were exposed to visual and tactile erotic stimuli to elicit penile erection. Whole blood was simultaneously aspirated from the corpus cavernosum and cubital vein during penile flaccidity and rigidity. Plasma aliquots were subjected to DPD analysis by means of matrix-assisted-laser-desorption-ionization mass mapping and electrospray-ionization quadrupole--time-of-flight mass spectrometry. High-resolution two-dimensional peptide mass mapping revealed differences in the systemic and cavernous plasma samples related to penile flaccidity and rigidity. Distinct signals were recognized in the cavernous but not in the systemic plasma obtained during flaccidity. These signals were not registered in the plasma samples obtained from the corpus cavernosum during rigid erection. Although one signal was identified as the blood coagulation-activating peptide XIIIa, the remaining two signals could not be related to any known peptide. These signals may represent unknown local peptidergic factors that might be involved in the regulation of penile flaccidity. Our study demonstrates that DPD is a feasible method for detecting differences in the cavernous and systemic blood in relation to the different functional conditions of the penile erectile tissue. Additional studies using DPD should include the analysis of blood samples taken from the cavernous meshwork of healthy subjects during penile tumescence and detumescence to establish DPD as

  18. Dissipative particle dynamics study of translational diffusion of rigid-chain rodlike polymer in nematic phase

    NASA Astrophysics Data System (ADS)

    Zhao, Tongyang; Wang, Xiaogong

    2013-09-01

    In this study, dissipative particle dynamics (DPD) method was employed to investigate the translational diffusion of rodlike polymer in its nematic phase. The polymer chain was modeled by a rigid rod composed of consecutive DPD particles and solvent was represented by independent DPD particles. To fully understand the translational motion of the rods in the anisotropic phase, four diffusion coefficients, D_{||}u, D_ bot u, D_{||}n, D_ bot n were obtained from the DPD simulation. By definition, D_{||}n and D_ bot n denote the diffusion coefficients parallel and perpendicular to the nematic director, while D_{||}u and D_ bot u denote the diffusion coefficients parallel and perpendicular to the long axis of a rigid rod u. In the simulation, the velocity auto-correlation functions were used to calculate the corresponding diffusion coefficients from the simulated velocity of the rods. Simulation results show that the variation of orientational order caused by concentration and temperature changes has substantial influences on D_{||}u and D_ bot u. In the nematic phase, the changes of concentration and temperature will result in a change of local environment of rods, which directly influence D_{||}u and D_ bot u. Both D_{||}n and D_ bot n can be represented as averages of D_{||}u and D_ bot u, and the weighted factors are functions of the orientational order parameter S2. The effect of concentration and temperature on D_{||}n and D_ bot n demonstrated by the DPD simulation can be rationally interpreted by considering their influences on D_{||}u, D_ bot u and the order parameter S2.

  19. Biochemical markers for bone turnover predict risk of vertebral fractures in postmenopausal women over 10 years: the Japanese Population-based Osteoporosis (JPOS) Cohort Study.

    PubMed

    Tamaki, J; Iki, M; Kadowaki, E; Sato, Y; Chiba, Y; Akiba, T; Matsumoto, T; Nishino, H; Kagamimori, S; Kagawa, Y; Yoneshima, H

    2013-03-01

    We evaluated how bone turnover might predict vertebral fracture risk in postmenopausal women over 10 years. After adjusting for age and femoral neck bone mineral density, high bone-specific alkaline phosphatase and total and free deoxypyridinoline at baseline predicted increased vertebral fracture risk in women with ≥ 5 years since menopause. The aim was to evaluate the ability of bone turnover markers (BTMs) in predicting vertebral fractures. Participants in the 1996 baseline survey of the JPOS Cohort Study included 522 postmenopausal women, with no diseases or medications affecting bone metabolism. Vertebral fractures were ascertained in three follow-up surveys (1999, 2002, and 2006). Initial fracture events were diagnosed morphometrically. The Poisson regression model was applied to estimate the rate ratio (RR) of the following log-transformed BTM values at baseline: osteocalcin and bone-specific alkaline phosphatase (BAP) in serum and C-terminal cross-linked telopeptide of type I collagen, total deoxypyridinoline (tDPD), and free deoxypyridinoline (fDPD) in urine. Eighty-three fracture events were diagnosed over a median follow-up period of 10.0 years. RR per standard deviation (SD) (95 % confidence interval) for BAP was 4.38 (1.45, 13.21) among 65 subjects with years since menopause (YSM) < 5 years. RRs per SD (95 % confidence interval) for BAP, tDPD, and fDPD were 1.39 (1.12, 1.74), 1.32 (1.05, 1.67), and 1.40 (1.12, 1.76), respectively, after adjusting for age and femoral neck bone mineral density (FN BMD) among 457 subjects with YSM ≥ 5 years. Of the 451 women followed at least once until 2002, RRs per SD for BAP, tDPD, and fDPD adjusted for age and FN BMD over 6 years were not significantly different from those over 10 years. BAP was associated with vertebral fracture risk among early postmenopausal women. BTMs can predict vertebral fractures independently of BMD among late postmenopausal women over a 10-year follow-up period.

  20. A simple analytical procedure to replace HPLC for monitoring treatment concentrations of chloramine-T on fish culture facilities

    USGS Publications Warehouse

    Dawson, Verdel K.; Meinertz, Jeffery R.; Schmidt, Larry J.; Gingerich, William H.

    2003-01-01

    Concentrations of chloramine-T must be monitored during experimental treatments of fish when studying the effectiveness of the drug for controlling bacterial gill disease. A surrogate analytical method for analysis of chloramine-T to replace the existing high-performance liquid chromatography (HPLC) method is described. A surrogate method was needed because the existing HPLC method is expensive, requires a specialist to use, and is not generally available at fish hatcheries. Criteria for selection of a replacement method included ease of use, analysis time, cost, safety, sensitivity, accuracy, and precision. The most promising approach was to use the determination of chlorine concentrations as an indicator of chloramine-T. Of the currently available methods for analysis of chlorine, the DPD (N,N-diethyl-p-phenylenediamine) colorimetric method best fit the established criteria. The surrogate method was evaluated under a variety of water quality conditions. Regression analysis of all DPD colorimetric analyses with the HPLC values produced a linear model (Y=0.9602 X+0.1259) with an r2 value of 0.9960. The average accuracy (percent recovery) of the DPD method relative to the HPLC method for the combined set of water quality data was 101.5%. The surrogate method was also evaluated with chloramine-T solutions that contained various concentrations of fish feed or selected densities of rainbow trout. When samples were analyzed within 2 h, the results of the surrogate method were consistent with those of the HPLC method. When samples with high concentrations of organic material were allowed to age more than 2 h before being analyzed, the DPD method seemed to be susceptible to interference, possibly from the development of other chloramine compounds. However, even after aging samples 6 h, the accuracy of the surrogate DPD method relative to the HPLC method was within the range of 80–120%. Based on the data comparing the two methods, the U.S. Food and Drug Administration

  1. A simple analytical procedure to replace HPLC for monitoring treatment concentrations of chloramine-T on fish culture facilities

    USGS Publications Warehouse

    Dawson, V.K.; Meinertz, J.R.; Schmidt, L.J.; Gingerich, W.H.

    2003-01-01

    Concentrations of chloramine-T must be monitored during experimental treatments of fish when studying the effectiveness of the drug for controlling bacterial gill disease. A surrogate analytical method for analysis of chloramine-T to replace the existing high-performance liquid chromatography (HPLC) method is described. A surrogate method was needed because the existing HPLC method is expensive, requires a specialist to use, and is not generally available at fish hatcheries. Criteria for selection of a replacement method included ease of use, analysis time, cost, safety, sensitivity, accuracy, and precision. The most promising approach was to use the determination of chlorine concentrations as an indicator of chloramine-T. Of the currently available methods for analysis of chlorine, the DPD (N,N-diethyl-p-phenylenediamine) colorimetric method best fit the established criteria. The surrogate method was evaluated under a variety of water quality conditions. Regression analysis of all DPD colorimetric analyses with the HPLC values produced a linear model (Y=0.9602 X+0.1259) with an r2 value of 0.9960. The average accuracy (percent recovery) of the DPD method relative to the HPLC method for the combined set of water quality data was 101.5%. The surrogate method was also evaluated with chloramine-T solutions that contained various concentrations of fish feed or selected densities of rainbow trout. When samples were analyzed within 2 h, the results of the surrogate method were consistent with those of the HPLC method. When samples with high concentrations of organic material were allowed to age more than 2 h before being analyzed, the DPD method seemed to be susceptible to interference, possibly from the development of other chloramine compounds. However, even after aging samples 6 h, the accuracy of the surrogate DPD method relative to the HPLC method was within the range of 80-120%. Based on the data comparing the two methods, the U.S. Food and Drug Administration has

  2. Analysis of 5-fluorouracil-related enzymes in pulmonary neuroendocrine carcinoma: differences in biological properties compared to epithelial carcinoma.

    PubMed

    Nagasaki, Toshiya; Tsuchiya, Tomoshi; Tagawa, Tsutomu; Honda, Sumihisa; Yamasaki, Naoya; Miyazaki, Takuro; Hidaka, Shigekazu; Hayashi, Tomayoshi; Nagayasu, Takeshi

    2010-11-01

    Dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyl transferase (OPRT), and thymidylate synthase (TS) levels correlate with sensitivity and resistance to 5-fluorouracil (5-FU). Few data are available on these enzymes in pulmonary neuroendocrine carcinoma, because 5-FU appears to have minimal effect on such carcinomas. This study investigated 5-FU-related enzymes in large-cell neuroendocrine carcinoma (LCNEC; n = 31) and small-cell lung carcinoma (SCLC; n = 15), comparing expression levels with epithelial carcinomas including adenocarcinoma (ADC; n = 34) and squamous cell carcinoma (SCC; n = 13) obtained from 93 patients with primary lung tumors. Levels of 5-FU-related enzyme mRNA were analyzed by laser capture microdissection, compared with immunohistochemical findings and correlated with clinicopathologic factors. LCNEC and SCLC showed significantly higher TS and OPRT mRNA levels than ADC. SCLC exhibited significantly higher TS mRNA levels than LCNEC (P = .002). LCNEC displayed significantly lower DPD mRNA levels than ADC (P < .001), with a similar tendency in SCLC. SCC showed significantly lower DPD (P < .01) and higher OPRT (P < .001) mRNA levels than ADC. When we divide the data by pathology into epithelial carcinoma and neuroendocrine carcinoma, malignant potentials and prognoses correlated with mRNA levels in epithelial carcinoma, but not in neuroendocrine carcinoma. Immunohistochemically, neuroendocrine carcinomas were immunonegative for DPD. A significant correlation was found between enzymatic mRNA and protein expression for DPD (R = .500) and a weak correlation was observed for TS (R = .294). Neuroendocrine carcinomas show characteristic patterns of expression for 5-FU-related enzymes, including low DPD mRNA and protein level and high TS mRNA level compared with adenocarcinomas. These results partially explain why 5-FU-based chemotherapy shows minimal efficacy against SCLC. Conversely, clinicopathological data and survival analysis indicates

  3. Un Marco Abierto: Un Manual de Matematicas y Ciencas Utilizando Inteligencias Multiples Disenado para Estudiantes Bilingues de Educacion General y Especial (An Open Framework: A Math and Science Manual Utilizing Multiple Intelligences Designed for Bilingual Students in General and Special Education).

    ERIC Educational Resources Information Center

    New York City Board of Education, Brooklyn, NY. Office of Bilingual Education.

    This manual incorporates a Multiple Intelligences perspective into its presentation of themes and lesson ideas for Spanish-English bilingual elementary school students in grades 4-8 and is designed for both gifted and special education uses. Each unit includes practice activities, semantic maps to illustrate and help organize ideas as well as…

  4. Combined simulation and experimental study of large deformation of red blood cells in microfluidic systems.

    PubMed

    Quinn, David J; Pivkin, Igor; Wong, Sophie Y; Chiam, Keng-Hwee; Dao, Ming; Karniadakis, George Em; Suresh, Subra

    2011-03-01

    We investigate the biophysical characteristics of healthy human red blood cells (RBCs) traversing microfluidic channels with cross-sectional areas as small as 2.7 × 3 μm. We combine single RBC optical tweezers and flow experiments with corresponding simulations based on dissipative particle dynamics (DPD), and upon validation of the DPD model, predictive simulations and companion experiments are performed in order to quantify cell deformation and pressure-velocity relationships for different channel sizes and physiologically relevant temperatures. We discuss conditions associated with the shape transitions of RBCs along with the relative effects of membrane and cytosol viscosity, plasma environments, and geometry on flow through microfluidic systems at physiological temperatures. In particular, we identify a cross-sectional area threshold below which the RBC membrane properties begin to dominate its flow behavior at room temperature; at physiological temperatures this effect is less profound.

  5. Combined Simulation and Experimental Study of Large Deformation of Red Blood Cells in Microfluidic Systems

    PubMed Central

    Quinn, David J.; Pivkin, Igor; Wong, Sophie Y.; Chiam, Keng-Hwee; Dao, Ming; Karniadakis, George Em; Suresh, Subra

    2011-01-01

    We investigate the biophysical characteristics of healthy human red blood cells (RBCs) traversing microfluidic channels with cross-sectional areas as small as 2.7 × 3 μm. We combine single RBC optical tweezers and flow experiments with corresponding simulations based on dissipative particle dynamics (DPD), and upon validation of the DPD model, predictive simulations and companion experiments are performed in order to quantify cell deformation and pressure–velocity relationships for different channel sizes and physiologically relevant temperatures. We discuss conditions associated with the shape transitions of RBCs along with the relative effects of membrane and cytosol viscosity, plasma environments, and geometry on flow through microfluidic systems at physiological temperatures. In particular, we identify a cross-sectional area threshold below which the RBC membrane properties begin to dominate its flow behavior at room temperature; at physiological temperatures this effect is less profound. PMID:21240637

  6. Concurrent material point method and molecular dynamics approach for simulating transient responses

    NASA Astrophysics Data System (ADS)

    Chen, Zhen; Su, Yu-Chen; Zhang, Hetao; Jiang, Shan; Sewell, Thomas D.

    2017-01-01

    To effectively simulate multiscale transient responses such as impact and penetration without the need to invoke a master/slave treatment, the multiscale material point method (Multi-MPM) is being developed wherein molecular dynamics (MD) at the nanoscale or dissipative particle dynamics (DPD) at the mesoscale are handled concurrently within the framework of the original MPM (continuum scale). The proposed numerical scheme for concurrently linking different scales is described here along with a preliminary error analysis. Representative examples for concurrent MPM and DPD and concurrent MPM and MD simulations were presented at SCCM-2015. Because the original MPM is an extension from computational fluid dynamics to solid dynamics, the proposed Multi-MPM might also become robust for dealing with multiphase interactions involving failure evolution.

  7. Mesoscale modeling of polyelectrolyte brushes with salt.

    PubMed

    Ibergay, Cyrille; Malfreyt, Patrice; Tildesley, Dominic J

    2010-06-03

    We report dissipative particle dynamics (DPD) simulations of a polyelectrolyte brush under athermal solvent conditions. The electrostatic interactions are calculated using the particle-particle particle-mesh (PPPM) method with charges distributed over the particles. The polymer beads, counterions, co-ions, and solvent particles are modeled explicitly. The DPD simulations show a dependence of the brush height on the grafting density and the charge fraction that is typical of the nonlinear osmotic brush regime. We report the effect of the addition of salt on the structural properties of the brush. In the case of a polyelectrolyte brush with a high surface coverage, the simulations reproduce the transition between the nonlinear osmotic brush regime where the thickness of the brush is independent of the salt concentration and the salted regime where the brush height decreases weakly with the salt concentration.

  8. Mesoscopic simulation of entanglements using dissipative particle dynamics: application to polymer brushes.

    PubMed

    Goujon, Florent; Malfreyt, Patrice; Tildesley, Dominic J

    2008-07-21

    We use a simple spring-spring repulsion to model entanglements between polymers in dissipative particle dynamics (DPD) simulations. The model is applied to a polymer brushes system to study lubrication. We demonstrate that this method leads to mechanical equilibrium in polymer brushes using the normal DPD time step. The number of bond crossings is calculated to provide a quantitative description of the entanglement. We demonstrate that it is possible to avoid 99% of the bond crossings with the values of spring-spring repulsion that can be used without significantly decreasing the time step. A shear force is applied to the system to study the effect of the decrease in the bond crossings on the structure and rheological properties of the brushes. In particular, we show how the friction coefficient increases with the decrease in the bond crossings of the polymers.

  9. Electro-optic spectral tuning in a fan-out double-prism domain periodically poled lithium niobate intracavity optical parametric oscillator.

    PubMed

    Chang, W K; Chung, H P; Lin, Y Y; Chen, Y H

    2016-08-15

    We report on the design and experimental demonstration of an electro-optically tunable, pulsed intracavity optical parametric oscillator (IOPO) based on a unique fan-out double-prism domain periodically poled lithium niobate (DPD PPLN) in a diode-pumped Nd:YVO4 laser. The PPLN device combines the functionalities of fan-out and ramped duty-cycle domain structured nonlinear crystals, working simultaneously as a continuous grating-period quasi-phase-matched optical parametric downconverter and an electro-optic beam deflector/Q switch in the laser system. When driving the fan-out DPD PPLN with a voltage pulse train and varying the DC offset of the pulse train, a pulsed IOPO was realized with its signal and idler being electro-optically tunable over the 1880 and 2453 nm bands at spectral tuning rates of 13.5 (measured) and 25.8 (calculated) nm/(kV/mm), respectively.

  10. Formation of incoherent deformation twin boundaries in a coarse-grained Al-7Mg alloy

    NASA Astrophysics Data System (ADS)

    Jin, S. B.; Zhang, K.; Bjørge, R.; Tao, N. R.; Marthinsen, K.; Lu, K.; Li, Y. J.

    2015-08-01

    Deformation twinning has rarely been observed in coarse grained Al and its alloys except under some extreme conditions such as ultrahigh deformation strain or strain rates. Here, we report that a significant amount of Σ3 deformation twins could be generated in a coarse-grained Al-7 Mg alloy by dynamic plastic deformation (DPD). A systematic investigation of the Σ3 boundaries shows that they are Σ3{112} type incoherent twin boundaries (ITBs). These ITBs have formed by gradual evolution from copious low-angle deformation bands through <111>-twist Σ boundaries by lattice rotation. These findings provide an approach to generate deformation twin boundaries in high stacking fault energy metallic alloys. It is suggested that high solution content of Mg in the alloy and the special deformation mode of DPD played an important role in formation of the Σ and ITBs.

  11. Analysis of the self-assembling and the defect annihilation processes in DSA using meso-scale simulation

    NASA Astrophysics Data System (ADS)

    Morita, Hiroshi; Norizoe, Yuki

    2015-03-01

    Recently, directed self-assembly (DSA) method is focused on as a next generation lithography technique. We performed the DPD simulations to analyze the self-assembling process of block copolymer in DSA using OCTA (in detail, see http://octa.jp) system. Using DPD simulation, we can obtain the phase separated structures at each moment consisted by block copolymer chains. As those structures are consisted by polymer chains, an analysis can be done on those structures. In this paper, we study the dynamics of end particles in the defect annihilation process to understand the dynamics of self-assembling of block copolymer in DSA. From our analysis, the end particles moves in advance than the change of domain structure in the defect annihilation process.

  12. Dislocation-pipe diffusion in nitride superlattices observed in direct atomic resolution

    PubMed Central

    Garbrecht, Magnus; Saha, Bivas; Schroeder, Jeremy L.; Hultman, Lars; Sands, Timothy D.

    2017-01-01

    Device failure from diffusion short circuits in microelectronic components occurs via thermally induced migration of atoms along high-diffusivity paths: dislocations, grain boundaries, and free surfaces. Even well-annealed single-grain metallic films contain dislocation densities of about 1014 m−2; hence dislocation-pipe diffusion (DPD) becomes a major contribution at working temperatures. While its theoretical concept was established already in the 1950s and its contribution is commonly measured using indirect tracer, spectroscopy, or electrical methods, no direct observation of DPD at the atomic level has been reported. We present atomically-resolved electron microscopy images of the onset and progression of diffusion along threading dislocations in sequentially annealed nitride metal/semiconductor superlattices, and show that this type of diffusion can be independent of concentration gradients in the system but governed by the reduction of strain fields in the lattice. PMID:28382949

  13. Analysis of the Differential Phase Detection Signal in Multi-level Run-Length Limited Read-Only Disk Driver

    NASA Astrophysics Data System (ADS)

    Shen, Quanhong; Pei, Jing; Xu, Haizheng; Wang, Lin; Xu, Duanyi

    2006-07-01

    Multilevel run-length-limited (ML-RLL) recording technology could be employed to increase the capacity of the read-only disc without changing optical and mechanical units. In this paper, the tracking error signal (TES) of differential phase detection (DPD) for ML-RLL digital versatile disk (DVD) read-only disk driver is analyzed in both theoretical and experimental way, the uniformity and symmetry of which are worse than that of the DVD read-only disk driver. The variation of peak to peak (PP) value distribution of the DPD signal in open loop of ML-RLL DVD read-only disk driver is about 2.6 times of that of the conventional DVD driver while the asymmetry is about 4 times. It is predicted that some improvements of the tracking servo system are needed in ML-RLL system.

  14. Modeling of polyethylene, poly(l-lactide), and CNT composites: a dissipative particle dynamics study

    PubMed Central

    2011-01-01

    Dissipative particle dynamics (DPD), a mesoscopic simulation approach, is used to investigate the effect of volume fraction of polyethylene (PE) and poly(l-lactide) (PLLA) on the structural property of the immiscible PE/PLLA/carbon nanotube in a system. In this work, the interaction parameter in DPD simulation, related to the Flory-Huggins interaction parameter χ, is estimated by the calculation of mixing energy for each pair of components in molecular dynamics simulation. Volume fraction and mixing methods clearly affect the equilibrated structure. Even if the volume fraction is different, micro-structures are similar when the equilibrated structures are different. Unlike the blend system, where no relationship exists between the micro-structure and the equilibrated structure, in the di-block copolymer system, the micro-structure and equilibrated structure have specific relationships. PMID:21711494

  15. Dislocation-pipe diffusion in nitride superlattices observed in direct atomic resolution

    NASA Astrophysics Data System (ADS)

    Garbrecht, Magnus; Saha, Bivas; Schroeder, Jeremy L.; Hultman, Lars; Sands, Timothy D.

    2017-04-01

    Device failure from diffusion short circuits in microelectronic components occurs via thermally induced migration of atoms along high-diffusivity paths: dislocations, grain boundaries, and free surfaces. Even well-annealed single-grain metallic films contain dislocation densities of about 1014 m-2 hence dislocation-pipe diffusion (DPD) becomes a major contribution at working temperatures. While its theoretical concept was established already in the 1950s and its contribution is commonly measured using indirect tracer, spectroscopy, or electrical methods, no direct observation of DPD at the atomic level has been reported. We present atomically-resolved electron microscopy images of the onset and progression of diffusion along threading dislocations in sequentially annealed nitride metal/semiconductor superlattices, and show that this type of diffusion can be independent of concentration gradients in the system but governed by the reduction of strain fields in the lattice.

  16. Dislocation-pipe diffusion in nitride superlattices observed in direct atomic resolution.

    PubMed

    Garbrecht, Magnus; Saha, Bivas; Schroeder, Jeremy L; Hultman, Lars; Sands, Timothy D

    2017-04-06

    Device failure from diffusion short circuits in microelectronic components occurs via thermally induced migration of atoms along high-diffusivity paths: dislocations, grain boundaries, and free surfaces. Even well-annealed single-grain metallic films contain dislocation densities of about 10(14) m(-2); hence dislocation-pipe diffusion (DPD) becomes a major contribution at working temperatures. While its theoretical concept was established already in the 1950s and its contribution is commonly measured using indirect tracer, spectroscopy, or electrical methods, no direct observation of DPD at the atomic level has been reported. We present atomically-resolved electron microscopy images of the onset and progression of diffusion along threading dislocations in sequentially annealed nitride metal/semiconductor superlattices, and show that this type of diffusion can be independent of concentration gradients in the system but governed by the reduction of strain fields in the lattice.

  17. Microstructural Analysis of Orientation-Dependent Recovery and Recrystallization in a Modified 9Cr-1Mo Steel Deformed by Compression at a High Strain Rate

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenbo; Zhang, Yubin; Mishin, Oleg V.; Tao, Nairong; Pantleon, Wolfgang; Juul Jensen, Dorte

    2016-09-01

    The evolution of the microstructure and texture during annealing of a modified ferritic/martensitic 9Cr-1Mo steel compressed by dynamic plastic deformation (DPD) to a strain of 2.3 has been investigated using transmission electron microscopy and electron backscatter diffraction. It is found that the duplex <111> + <100> fiber texture formed by DPD is transformed during annealing to a dominant <111> fiber texture, and that crystallites of the <111> component have an advantage during both nucleation and growth. Detailed characterization of the microstructural morphology, and estimation of the stored energies in <111>- and <100>-oriented regions in deformed and annealed samples, as well as investigations of the growth of recrystallizing grains, are used to analyze the annealing behavior. It is concluded that recrystallization in the given material occurs by a combination of oriented nucleation and oriented growth.

  18. Dissipative particle dynamics: Systematic parametrization using water-octanol partition coefficients.

    PubMed

    Anderson, Richard L; Bray, David J; Ferrante, Andrea S; Noro, Massimo G; Stott, Ian P; Warren, Patrick B

    2017-09-07

    We present a systematic, top-down, thermodynamic parametrization scheme for dissipative particle dynamics (DPD) using water-octanol partition coefficients, supplemented by water-octanol phase equilibria and pure liquid phase density data. We demonstrate the feasibility of computing the required partition coefficients in DPD using brute-force simulation, within an adaptive semi-automatic staged optimization scheme. We test the methodology by fitting to experimental partition coefficient data for twenty one small molecules in five classes comprising alcohols and poly-alcohols, amines, ethers and simple aromatics, and alkanes (i.e., hexane). Finally, we illustrate the transferability of a subset of the determined parameters by calculating the critical micelle concentrations and mean aggregation numbers of selected alkyl ethoxylate surfactants, in good agreement with reported experimental values.

  19. Imaging dynamics on the F + H2O -> HF + OH potential energy surfaces from wells to barriers.

    PubMed

    Otto, Rico; Ma, Jianyi; Ray, Amelia W; Daluz, Jennifer S; Li, Jun; Guo, Hua; Continetti, Robert E

    2014-01-24

    The study of gas-phase reaction dynamics has advanced to a point where four-atom reactions are the proving ground for detailed comparisons between experiment and theory. Here, a combined experimental and theoretical study of the dissociation dynamics of the tetra-atomic FH2O system is presented, providing snapshots of the F + H2O → HF + OH reaction. Photoelectron-photofragment coincidence measurements of the dissociative photodetachment (DPD) of the F(-)(H2O) anion revealed various dissociation pathways along different electronic states. A distinct photoelectron spectrum of stable FH-OH complexes was also measured and attributed to long-lived Feshbach resonances. Comparison to full-dimensional quantum calculations confirms the sensitivity of the DPD measurements to the subtle dynamics on the low-lying FH2O potential energy surfaces over a wide range of nuclear configurations and energies.

  20. Simulation on electrical field distribution and fiber falls in melt electrospinning.

    PubMed

    Wang, Xin; Liu, Yong; Zhang, Chi; An, Ying; He, Xuetao; Yang, Weimin

    2013-07-01

    Electrospinning is now a typical way of direct and consecutive producing nanofibers. In order to comprehensively understand the change of fiber chains in falling process of electrospinning, the article import dissipative particle dynamics (DPD) mesoscale simulation method into electrospinning study. In current work, an electrical force formula is proposed after simulation of the distribution of electrostatic field in electrospinning using Finite Element Method. Then, various electrostatic force, temperature and viscosity in electrospinning system are qualitatively simulated by DPD simulation. Results showed that the falling velocity of fiber increased with the increase of electrostatic force. It was found that the lower the polymer viscosity, the quicker the fiber falls. And the diameter of fiber significantly increased with augment of viscosity. Both of above are agree with experimental results. We also found that the falling velocity of fiber is in contrast with length of polymer chains, which has not been found in experiments.

  1. Emotional memory and perception of emotional faces in patients suffering from depersonalization disorder.

    PubMed

    Montagne, Barbara; Sierra, Mauricio; Medford, Nick; Hunter, Elaine; Baker, Dawn; Kessels, Roy P C; de Haan, Edward H F; David, Anthony S

    2007-08-01

    Previous work has shown that patients with depersonalization disorder (DPD) have reduced physiological responses to emotional stimuli, which may be related to subjective emotional numbing. This study investigated two aspects of affective processing in 13 patients with DPD according to the DSM-IV criteria and healthy controls: the perception of emotional facial expressions (anger, disgust, fear, happiness, sadness, and surprise) and memory for emotional stimuli. Results revealed a specific lack of sensitivity to facial expression of anger in patients, but normal enhancement of memory for peripheral aspects of arousing emotional material. The results are consistent with altered processing of threat-related stimuli but intact consolidation processes, at least when the stimuli involved are potently arousing.

  2. Dissipative particle dynamics: Systematic parametrization using water-octanol partition coefficients

    NASA Astrophysics Data System (ADS)

    Anderson, Richard L.; Bray, David J.; Ferrante, Andrea S.; Noro, Massimo G.; Stott, Ian P.; Warren, Patrick B.

    2017-09-01

    We present a systematic, top-down, thermodynamic parametrization scheme for dissipative particle dynamics (DPD) using water-octanol partition coefficients, supplemented by water-octanol phase equilibria and pure liquid phase density data. We demonstrate the feasibility of computing the required partition coefficients in DPD using brute-force simulation, within an adaptive semi-automatic staged optimization scheme. We test the methodology by fitting to experimental partition coefficient data for twenty one small molecules in five classes comprising alcohols and poly-alcohols, amines, ethers and simple aromatics, and alkanes (i.e., hexane). Finally, we illustrate the transferability of a subset of the determined parameters by calculating the critical micelle concentrations and mean aggregation numbers of selected alkyl ethoxylate surfactants, in good agreement with reported experimental values.

  3. Cognitive-behavioral therapy for patients with Parkinson's disease and comorbid major depressive disorder.

    PubMed

    Farabaugh, Amy; Locascio, Joseph J; Yap, Liang; Growdon, John; Fava, Maurizio; Crawford, Christine; Matthews, John; McCutchen, Jesse; Buchin, Jacqueline; Pava, Joel; Alpert, Jonathan E

    2010-01-01

    Depression has been recognized as a common feature of Parkinson's disease (PD), and is the most prevalent psychiatric disorder in PD patients. The authors sought to determine whether cognitive-behavioral therapy (CBT) is effective in the treatment of depression within the context of PD (dPD). The authors enrolled 8 depressed PD patients into an open treatment study of 12 weeks of individual CBT treatment. There was a significant linear decrease in mean Hamilton Rating Scale for Depression (17-item) scores over Weeks 0 to 12, and 57% of patients (4/7) met criteria for remission at endpoint. This uncontrolled study suggests that CBT may be effective in treating dPD and may be an alternative or adjunct to pharmacological treatment.

  4. Dihydropyrimidine Dehydrogenase Deficiency in Two Malaysian Siblings with Abnormal MRI Findings

    PubMed Central

    Chen, Bee Chin; Mohd Rawi, Rowani; Meinsma, Rutger; Meijer, Judith; Hennekam, Raoul C.M.; van Kuilenburg, André B.P.

    2014-01-01

    Dihydropyrimidine dehydrogenase (DPD) deficiency is an autosomal recessive disorder of the pyrimidine metabolism. Deficiency of this enzyme leads to an accumulation of thymine and uracil and a deficiency of metabolites distal to the catabolic enzyme. The disorder presents with a wide clinical spectrum, ranging from asymptomatic to severe neurological manifestations, including intellectual disability, seizures, microcephaly, autistic behavior, and eye abnormalities. Here, we report on an 11-year-old Malaysian girl and her 6-year-old brother with DPD deficiency who presented with intellectual disability, microcephaly, and hypotonia. Brain MRI scans showed generalized cerebral and cerebellar atrophy and callosal body dysgenesis in the boy. Urine analysis showed strongly elevated levels of uracil in the girl and boy (571 and 578 mmol/mol creatinine, respectively) and thymine (425 and 427 mmol/mol creatinine, respectively). Sequence analysis of the DPYD gene showed that both siblings were homozygous for the mutation c.1651G>A (pAla551Thr). PMID:25565930

  5. High permeability explains the vulnerability of the carbon store in drained tropical peatlands

    NASA Astrophysics Data System (ADS)

    Baird, Andy J.; Low, Robert; Young, Dylan; Swindles, Graeme T.; Lopez, Omar R.; Page, Susan

    2017-02-01

    Tropical peatlands are an important global carbon (C) store but are threatened by drainage for palm oil and wood pulp production. The store's stability depends on the dynamics of the peatland water table, which in turn depend on peat permeability. We found that an example of the most abundant type of tropical peatland—ombrotrophic domes—has an unexpectedly high permeability similar to that of gravel. Using computer simulations of a natural peat dome (NPD) and a ditch-drained peat dome (DPD) we explored how such high permeability affects water tables and peat decay. High permeability has little effect on NPD water tables because of low hydraulic gradients from the center to the margin of the peatland. In contrast, DPD water tables are consistently deep, leaving the upper meter of peat exposed to rapid decay. Our results reveal why ditch drainage precipitates a rapid destabilization of the tropical peatland C store.

  6. Dietary calcium, sodium, phosphorus, and protein and bone metabolism in elderly Japanese women: a pilot study using the duplicate portion sampling method.

    PubMed

    Nakamura, Kazutoshi; Hori, Yasushi; Nashimoto, Mitsue; Okuda, Yoko; Miyazaki, Hideo; Kasai, Yasunori; Yamamoto, Masaharu

    2004-04-01

    Associations between dietary factors and bone metabolism in Asians have not been thoroughly investigated. The purpose of this study was to determine the effect of dietary intake of calcium (Ca), phosphorus (P), sodium (Na), and protein on bone metabolism in elderly Japanese women by the duplicate portion sampling method. The subjects were 43 healthy female volunteers (mean age, 68.3 y; standard deviation, 6.8). Dietary nutrients were directly determined by using a 24-h duplicate meal portion. Serum osteocalcin and bone alkaline phosphatase and urinary deoxypyridinoline (DPD) and type I collagen cross-linked N-telopeptides (NTX-I) were measured as markers of bone turnover. Hormones related to bone metabolism, including serum 25-hydroxyvitamin D(3), 1,25-dihydroxyvitamin D(3), and intact parathyroid hormone also were determined. Urinary parameters were corrected for urinary creatinine concentration. The mean (standard deviation) daily dietary intakes of Ca, P, Na, and protein were 660 (195) mg, 996 (208) mg, 4080 (1142) mg, and 63.9 (15.5) g, respectively. Dietary Ca was negatively correlated with urinary DPD (r = -0.417, P = 0.005) and NTX-I (r = -0.324, P = 0.034), and dietary P was negatively correlated with urinary DPD (r = -0.307, P = 0.045). Multiple regression analysis showed that only dietary Ca was associated with urinary DPD and NTX-I. Dietary Ca intake was significantly associated with bone resorption markers, but no other dietary factors were associated with any of the biochemical markers. The major factor having an adverse effect on the bone health of the elderly Japanese women is low Ca intake and not other dietary minerals or protein.

  7. Search for CHARM pentaquarks in ZEUS at HERA

    SciTech Connect

    Eisenberg, Yehuda

    2006-02-11

    Using the full 1996 - 2000 ZEUS data at HERA (121 pb-1) we have searched for the {theta}{sub c}{sup 0}(3100) pentaquark in the photoproduction and DIS regime. The search has yielded negative results. The 95% C.L. upper limits on the visible rate R({theta}{sub c}{sup 0} {yields} D*p/D*) is 0.23% (0.35% for DIS)

  8. Continuation through Singularity of Continuum Multiphase Algorithms

    DTIC Science & Technology

    2013-03-01

    15]. The connection between MDPD and SPH was then clarified by Español and Revenga [16], who introduced a smoothed DPD (SDPD) method as a SPH...and H. A. Posch, Phys. Rev. E 62, 4968 (2000). [16] P. Español and M. Revenga, Phys. Rev. E 67, 026705 (2003). [17] P. Español , M. Serrano, and H. C

  9. A portable toxicity biosensor using freeze-dried recombinant bioluminescent bacteria.

    PubMed

    Choi, Sue Hyung; Gu, Man Bock

    2002-05-01

    A portable biosensor has been developed to meet the demands of field toxicity analysis. This biosensor consists of three parts, a freeze-dried biosensing strain within a vial, a small light-proof test chamber, and an optic-fiber connected between the sample chamber and a luminometer. Various genetically engineered bioluminescent bacteria were freeze-dried to measure different types of toxicity based upon their modes of action. GC2 (lac::luxCDABE), a constitutively bioluminescent strain, was used to monitor the general toxicity of samples through a decrease in its bioluminescence, while specific toxicity was detected through the use of strains such as DPD2540 (fabA::luxCDABE), TV1061 (grpE::luxCDABE), DPD2794 (recA::luxCDABE), and DPD2511 (katG::luxCDABE). These inducible strains show an increase in bioluminescence under specific stressful conditions, i.e. membrane-, protein-, DNA-, and oxidative-stress, respectively. The toxicity of a sample could be detected by measuring the bioluminescence 30 min after addition to the freeze-dried strains. In an attempt to enhance the sensitivity of the freeze-dried cells, glucose and Tween 80 were tested as additives. It was found that the addition of glucose had a negative effect on the viability of the freeze-dried cells, while samples having Tween 80 showed an increase in their viability. On the other hand, the addition of either Tween 80 or glucose decreased the final bioluminescent response of DPD2540 in response to 4-chlorophenol. Using these strains, many different chemicals were tested and characterized. This portable biosensor, with a very simple protocol, can be used for field sample analysis and the monitoring of various water systems on-site.

  10. The First Case of Severe Takotsubo Cardiomyopathy Associated with 5-Fluorouracil in a Patient with Abnormalities of Both Dihydropyrimidine Dehydrogenase (DPYD) and Thymidylate Synthase (TYMS) Genes

    PubMed Central

    Smith, Melissa; Maloney, Antonio

    2016-01-01

    5-Fluorouracil (5-FU) is the backbone of the chemotherapy regimens approved for treatment of many malignancies, especially colorectal cancer (CRC). The incidence of cardiotoxicity associated with 5-FU ranges between 1.5% to 18% and is most commonly manifested as anginal symptoms. Cardiomyopathy is very rarely reported with 5-FU and capecitabine. A 35-year-old Caucasian male with T3, N1, M0 rectal cancer after the initial neoadjuvant chemoradiation with 5FU/LV followed by surgical abdominoperineal resection (APR), began mFOLFOX6 in the adjuvant setting. Following the first treatment, he developed severe cardiomyopathy, with a drop in ejection fraction (EF) to 19% from normal. The cardiac workup showed no ischemic or other etiologies to explain this cardiac event. He was a nonsmoker and only occasionally drank alcohol. He had no previous or family history of heart disease and had normal cholesterol level. He was treated for severe congestive heart failure (CHF). When the patient presented to us for second opinion, we decided to examine him for dihydropyrimidine dehydrogenase (DPD) deficiency and thymidylate synthase (TYMS) polymorphism. The patient was found to be heterozygous for the c.85T>C mutation, resulting in reduced DPYD enzymatic activity and homozygous for TYMS 5’TSER genotype 2R/2R *f. Our group first identified and reported P453L (1358C>T) type DPYD germline mutation in a patient who developed 5-FU induced cardiotoxicity. In this paper, we describe the first case of cardiomyopathy related to DPD deficiency and homozygous polymorphism of TYMS in a patient with colon cancer following 5-FU containing regimen. Fluorouracil-related cardiomyopathy has to be anticipated and treated to prevent the serious consequence of cardiac dysfunction. The prospective testing for DPD deficiency in patients might prevent DPD-deficient patients from severe toxicity or even death, and therefore the development of a unified screening method is warranted. PMID:27752409

  11. Biomechanics of Hybrid Anterior Cervical Fusion and Artificial Disc Replacement in 3-Level Constructs: An In Vitro Investigation

    PubMed Central

    Liao, Zhenhua; Fogel, Guy R.; Pu, Ting; Gu, Hongsheng; Liu, Weiqiang

    2015-01-01

    Background The ideal surgical approach for cervical disk disease remains controversial, especially for multilevel cervical disease. The purpose of this study was to investigate the biomechanics of the cervical spine after 3-level hybrid surgery compared with 3-level anterior cervical discectomy and fusion (ACDF). Material/Methods Eighteen human cadaveric spines (C2-T1) were evaluated under displacement-input protocol. After intact testing, a simulated hybrid construct or fusion construct was created between C3 to C6 and tested in the following 3 conditions: 3-level disc plate disc (3DPD), 3-level plate disc plate (3PDP), and 3-level plate (3P). Results Compared to intact, almost 65~80% of motion was successfully restricted at C3-C6 fusion levels (p<0.05). 3DPD construct resulted in slight increase at the 3 instrumented levels (p>0.05). 3PDP construct resulted in significant decrease of ROM at C3-C6 levels less than 3P (p<0.05). Both 3DPD and 3PDP caused significant reduction of ROM at the arthrodesis level and produced motion increase at the arthroplasty level. For adjacent levels, 3P resulted in markedly increased contribution of both upper and lower adjacent levels (p<0.05). Significant motion increases lower than 3P were only noted at partly adjacent levels in some conditions for 3DPD and 3PDP (p<0.05). Conclusions ACDF eliminated motion within the construct and greatly increased adjacent motion. Artificial cervical disc replacement normalized motion of its segment and adjacent segments. While hybrid conditions failed to restore normal motion within the construct, they significantly normalized motion in adjacent segments compared with the 3-level ACDF condition. The artificial disc in 3-level constructs has biomechanical advantages compared to fusion in normalizing motion. PMID:26529430

  12. Altered Resting-State Brain Activity and Connectivity in Depressed Parkinson's Disease.

    PubMed

    Hu, Xiao; Song, Xiaopeng; Li, Erfeng; Liu, Jiajia; Yuan, Yonggui; Liu, Weiguo; Liu, Yijun

    2015-01-01

    Depressive symptoms are common in Parkinson's disease (PD), but the neurophysiological mechanisms of depression in PD are poorly understood. The current study attempted to examine disrupted spontaneous local brain activities and functional connectivities that underlie the depression in PD. We recruited a total of 20 depressed PD patients (DPD), 40 non-depressed PD patients (NDPD) and 43 matched healthy controls (HC). All the subjects underwent neuropsychological tests and resting-state fMRI scanning. The between-group differences in the amplitude of low frequency fluctuations (ALFF) of BOLD signals were examined using post-hoc tests after the analysis of covariance. Compared with the NDPD and HC, the DPD group showed significantly increased ALFF in the left median cingulated cortex (MCC). The functional connectivity (FC) between left MCC and all the other voxels in the brain were then calculated. Compared with the HC and NDPD group, the DPD patients showed stronger FC between the left MCC and some of the major nodes of the default mode network (DMN), including the post cingulated cortex/precuneus, medial prefrontal cortex, inferior frontal gyrus, and cerebellum. Correlation analysis revealed that both the ALFF values in the left MCC and the FC between the left MCC and the nodes of DMN were significantly correlated with the Hamilton Depression Rating Scale score. Moreover, higher local activities in the left MCC were associated with increased functional connections between the MCC and the nodes of DMN in PD. These abnormal activities and connectivities of the limbic-cortical circuit may indicate impaired high-order cortical control or uncontrol of negative mood in DPD, which suggested a possible neural mechanism of the depression in PD.

  13. Method with high-throughput screening potential for antioxidative substances using Escherichia coli biosensor katG'::lux.

    PubMed

    Tienaho, Jenni; Sarjala, Tytti; Franzén, Robert; Karp, Matti

    2015-11-01

    A new method is described for the rapid real-time screening of antioxidative properties using a recombinant Escherichia coli DPD2511 biosensor. This microplate technique, without time-consuming pre-incubations and handling, has potential for a high-throughput search of bioactive compounds. Special emphasis was given to obtaining highly reliable and repeatable results. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Radio Frequency Emitter Geolocation Using Cubesats

    DTIC Science & Technology

    2014-03-27

    estimate the signal propagation time. TOA depends on precision timing between the signal source and the receiver. This research focuses on the... depends on the distance between the sensors, the range to the target, and the bandwidth of 16 the signal of interest (SOI). Resolution is especially...2.3.4 Single Step Approach. The DPD algorithm takes a different approach to solving for position with a set of receivers. Weiss and Amar [18], along

  15. Emotional Experience and Awareness of Self: Functional MRI Studies of Depersonalization Disorder

    PubMed Central

    Medford, Nick; Sierra, Mauricio; Stringaris, Argyris; Giampietro, Vincent; Brammer, Michael J.; David, Anthony S.

    2016-01-01

    This paper presents functional MRI work on emotional processing in depersonalization disorder (DPD). This relatively neglected disorder is hallmarked by a disturbing change in the quality of first-person experience, almost invariably encompassing a diminished sense of self and an alteration in emotional experience such that the sufferer feels less emotionally reactive, with emotions experienced as decreased or “damped down,” so that emotional life seems to lack spontaneity and subjective validity. Here we explored responses to emotive visual stimuli to examine the functional neuroanatomy of emotional processing in DPD before and after pharmacological treatment. We also employed concurrent skin conductance measurement as an index of autonomic arousal. In common with previous studies we demonstrated that in DPD, there is attenuated psychophysiological response to emotional material, reflected in altered patterns of (i) regional brain response, (ii) autonomic responses. By scanning participants before and after treatment we were able to build on previous findings by examining the changes in functional MRI response in patients whose symptoms had improved at time 2. The attenuation of emotional experience was associated with reduced activity of the insula, whereas clinical improvement in DPD symptoms was associated with increased insula activity. The insula is known to be implicated in interoceptive awareness and the generation of feeling states. In addition an area of right ventrolateral prefrontal cortex emerged as particularly implicated in what may be “top-down” inhibition of emotional responses. The relevance of these findings to the wider study of emotion, self-related processes, and interoception is discussed. PMID:27313548

  16. Effect of Bioaerosol on the Release of Iodine from Iodine Treated Filters

    DTIC Science & Technology

    2011-12-01

    proportional to the total I2 concentration ( HACH 2003; Lee et al., 2009). Ten mL of the collection medium was analyzed at a wavelength of 530 nm...using a DR⁄4000 V spectrophotometer ( HACH , Loveland, CO, USA). The detection limit of this spectrophotometer using HACH Program: 2100 provided in the...using HACH Program: 2100 with the DPD method was established; the R2 value was 0.9992 as shown in Figure 3. The iodine concentration of each test

  17. Bone turnover in malnourished children.

    PubMed

    Branca, F; Robins, S P; Ferro-Luzzi, A; Golden, M H

    Pyridinoline (PYD) and deoxypyridinoline (DPD) are cross-linking aminoacids of collagen that are located mainly in bone and cartilage. When bone matrix is resorbed these cross-links are quantitatively excreted in the urine and therefore represent specific markers. We have measured the urinary excretion rate of PYD and DPD in 46 severely malnourished boys to assess their skeletal turnover and to relate this to their subsequent rate of growth. The children were aged 13 months (SD 6), and height-for-age was -3.6 (1.6) Z-score, and weight-for-height was -2.4 (0.8) Z-score. PYD excretion when malnourished and after "recovery" was 11.2 (4.6) nmol h-1m-2 and 32.2 (10.8) nmol h-1m-2 and DPD excretion was 2.6 (1.3) nmol h-1m-2 and 7.5 (3.0) nmol h-1m-2, respectively. The ratio of the two cross-links did not change with recovery. These data show that cartilage and bone turnover is much lower in the malnourished than in the recovered child. There was no difference in the degree of depression of turnover between the children with marasmus, marasmic-kwashiorkor, or kwashiorkor. The rate of height gain during recovery was significantly related to cross-link excretion, age, and weight-for-height on admission. These three factors accounted for 44% of the variance in the height velocity of the children. PYD and DPD excretion rate could be used to assess therapeutic interventions designed to alleviate stunting.

  18. Detection of pulmonary calcification in haemodialised patients by whole-body scintigraphy and the impact of the calcification to parameters of spirometry.

    PubMed

    Rajkovača, Zvezdana; Kovačević, Peđa; Jakovljević, Biljana; Erić, Zelimir

    2010-11-01

    The early diagnosis of metastatic pulmonary calcification is beneficial, as some patients may develop restrictive changes in respiratory function or in some cases lethal acute respiratory distress. The aim of the study was to evaluate whether scanning with ⁹⁹(m)Tc DPD might be useful in early diagnosis of pulmonary calcification in setting of chronic renal failure and hemodialysis and if presence of pulmonary calcification is associated with an abnormality in respiratory parameters. Forty-two patients with end-stage renal disease, who were treated by regular haemodialysis, were investigated. Twenty five (59.5%) out of forty two patients had increased lung uptake of ⁹⁹(m)Tc DPD at whole body scintigraphy-grade 2 group. These patients were on dialysis 149±26 months compared with 57±16 months in 17 patients with a normal lung uptake of ⁹⁹(m)Tc DPD at whole body scintigraphy- grade 1 group (p<0.01). In grade 2 group 22 patients (88%) had significantly lower (p<0.01) parameters of spirometry (FEF25-75, FEF75 FEF50, FEF25) compared to predicted values while in grade 1 group the parameters were significantly lower in only six patients (35.3%). There was statistically insignificant difference between these two groups regarding parathyroid hormone level (p>0.05). These observations confirm previous findings that scintigraphy with ⁹⁹(m)Tc DPD may be efficious in early diagnosis of pulmonary calcification in hemodialised patients as well as the fact that spirometry is useful in patients with confirmed pulmonary calcifications.

  19. Variabilidad de la Estación de Crecimiento en la Región Sur de Tamaulipas en condiciones climaticas actuales y futuras.

    NASA Astrophysics Data System (ADS)

    Medina-Barrios, M.; Conde-Alvarez, C.; Gay-Garcia, C.

    2007-05-01

    El impacto de la variabilidad y cambio climáticos, afectan el potencial agrícola de la Región Sur de Tamaulipas. Además de los cambios estacionales, bajos rendimientos agrícolas, el manejo de los cultivos y las políticas locales de producción, existe la incertidumbre del mercado regional para los pequeños y grandes productores. La diversificación agrícola ha sido una alternativa para enfrentar las condiciones imperantes en esta región. Pero ésta ha provocado la fragmentación territorial, por lo que sólo algunos productores logran competir en un mercado nacional. Existe una preocupación generalizada por buscar soluciones que permitan que la población que es afectada por la inseguridad de la producción agrícola y económica, pueda adaptarse a las variaciones climáticas que afectan el proceso productivo. La seguridad alimentaría queda sujeta a la fluctuación de las importaciones para los sectores básicos y a las estrategias mercantiles de empresas trasnacionales. La percepción local sugiere un número creciente de eventos climatológicos extremos, constantes y severos en los últimos 20 años, con el aumento creciente de pérdidas económicas. El análisis se centra en la disponibilidad de agua, agregándose un aspecto de capital importancia como es la variabilidad interanual de la lluvia, que condiciona muy fuertemente el riesgo agrícola en el trópico seco, siendo ésta la que determina el momento de inicio de la estación favorable para el crecimiento y su duración. En este trabajo se han obtenido modelos de la distribución espacial de la precipitación y temperaturas, para el escenario base 1961-1990, el escenario actual 1971-2000, para algunos años El Niño y La Niña, así como para los escenarios de Cambio Climático HADLEY, ECHAM y GFDL, con escenarios A2 y B2, para las décadas de los 20s y 50s, para establecer el inicio y duración de la Estación de Crecimiento, utilizando Sistemas de Información Geográfica (ArcView). Estos

  20. An osteogenesis imperfecta case with breast cancer.

    PubMed

    Taira, Fumi; Shimizu, Hideo; Kosaka, Taijiro; Saito, Mitsue; Kasumi, Fujio

    2014-11-01

    Osteogenesis imperfecta (OI) is a rare connective tissue disease characterized by abnormalities of type 1 collagen and an increased risk of bone fractures. Several OI cases with malignancies have been reported. Herein, we describe an OI case with breast cancer. A 36-year-old premenopausal woman with OI was admitted to our hospital for evaluation of a right breast lump. We diagnosed right breast cancer with axillary and parasternal lymph node metastasis (T2N3M0 stage IIIC). The tumor had increased in size and tumor markers were elevated after 10 months of hormone therapy. We performed a right mastectomy and axillary dissection. She subsequently received adjuvant chemotherapy and radiotherapy. She is currently taking trastuzumab and tamoxifen. Anesthesia is challenging in OI patients because of difficulty with airway control and intubation. We performed the mastectomy in this case without difficulty by working in cooperation with experienced anesthesiologists, orthopedists, and other medical personnel. Some OI patients reportedly have severe 5-fluorouracil (5-FU) toxicity related to dihydropyrimidine dehydrogenase (DPD) deficiency. DPD is the main enzyme involved in the catabolism of 5-FU. Our present case also had low DPD activity and we thus chose epirubicin and cyclophosphamide for chemotherapy. Our search of the literature yielded only two OI cases with breast cancer as of April 2011. To our knowledge, this is the first case reported in Japan.

  1. Bone Density, Osteocalcin and Deoxypyridinoline for Early Detection of Osteoporosis in Obese Children.

    PubMed

    El-Dorry, Ghada; Ashry, Hala; Ibrahim, Tarek; Elias, Tahany; Alzaree, Fatma

    2015-09-15

    This study aimed at comparing between bone density using DEXA, serum osteocalcin and urinary DPD in obese and non obese prepubertal children. After taking the consent of eighty children they were subjected to: full examination, anthropometric measurements, blood samples were withdrawn to determine serum osteocalcin, Ca, Ph, alkaline phosphatase, and urinary DPD. Bone densities, body composition of the whole body were examined using DEXA. Data were analyzed using SPSS. All anthropometric variables showed significant increase in obese children except for height in comparison to control group. Total mass, lean + BMC, lean, fat, area, BMC, BMD and Z score of the whole body were significantly increased in obese children. Serum calcium showed significant increase while alkaline phosphatase was significantly decreased in obese children. DPD showed no significant difference between obese and non obese children. Significant negative correlation was found between ca, lean, lean + BMC and total mass. Serum alkaline phosphatase showed also a significant negative correlation with (lean + BMC and total mass). Serum osteocalcin showed negative significant correlation with area, BMC, BMD, lean and Z score. Obese children showed significant increase in anthropometric and DEXA parameters, increase in serum calcium and significant decrease in serum alkaline phosphatase. Osteocalcin was negatively correlated with most of DEXA results.

  2. Establishing a clinically relevant cutoff to the Dependency Scale from the dimensional clinical personality inventory.

    PubMed

    Carvalho, Lucas de F; Pianowski, Giselle; Filho, Nelson H

    2017-05-01

    The Clinical Dimensional Personality Inventory (IDCP) is a 163-item self-report tool developed for the assessment of 12 dimensions of personality pathology. One of the scales comprising the instrument-the Dependency scale-is intended to provide psychometric information on traits closely related to the Dependent Personality Disorder (DPD). In the present study, we used both Item Response Theory modeling and Receiver Operating Characteristic curve analysis to establishing a clinically meaningful cutoff for the IDCP Dependency Scale. Participants were 2.481 adults, comprised by outpatients diagnosed with DPD, outpatients diagnosed with other PDs, and adults from the general population. The Wright's item map graphing technique revealed that outpatients were located at the very high levels in the latent scale continuum of the Dependency Scale, with a very large effect size for the mean difference between patients and non-patients. The ROC curve analysis supported a cutoff at 2.3 points in the Dependency Scale, which yielded 0.86 of sensitivity and 0.79 of specificity. Findings from the present investigation suggest the IDCP Dependency Scale is useful as a screening tool of the core features of the DPD. We address potential clinical applications for the instrument, and discuss limitations from the present study. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  3. Application of mesoscale simulation to explore the aggregate morphology of pH-sensitive nanoparticles used as the oral drug delivery carriers under different conditions.

    PubMed

    Wang, Yan; Chen, Bo Zhi; Liu, Yue Jin; Wu, Zhi Min; Guo, Xin Dong

    2017-03-01

    The pH-sensitive nanoparticles are selected as the potentially promising oral protein and peptide drug carriers due to their excellent performance. With the poly (lactic-co-glycolic acid)/hydroxypropyl methylcellulose phthalate (PLGA/HP55) nanoparticle as a model nanoparticle, the structure-property relationship of nanoparticles with different conditions is investigated by dissipative particle dynamics (DPD) simulations in our work. In the oral drug delivery system, the poly (lactic-co-glycolic acid) (PLGA) is hydrophobic polymer, hydroxypropyl methylcellulose phthalate (HP55) is pH-sensitive enteric polymer which used to protect the nanoparticles through the stomach and polyvinyl alcohol (PVA) is hydrophilic polymer as the stabilizer. It can be seen from DPD simulations that all polymer molecules form spherical core-shell nanoparticles with stabilizer PVA molecules adsorbed on the outer surface of the PLGA/HP55 matrix at certain compositions. The DPD simulation study can provide microscopic insight into the formation and morphological changes of pH-sensitive nanoparticles which is useful for the design of new materials for high-efficacy oral drug delivery. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Extremely rapid acclimation of Escherichia coli to high temperature over a few generations of a fed-batch culture during slow warming

    PubMed Central

    Guyot, Stéphane; Pottier, Laurence; Hartmann, Alain; Ragon, Mélanie; Hauck Tiburski, Julia; Molin, Paul; Ferret, Eric; Gervais, Patrick

    2014-01-01

    This study aimed to demonstrate that adequate slow heating rate allows two strains of Escherichia coli rapid acclimation to higher temperature than upper growth and survival limits known to be strain-dependent. A laboratory (K12-TG1) and an environmental (DPD3084) strain of E. coli were subjected to rapid (few seconds) or slow warming (1°C 12 h−1) in order to (re)evaluate upper survival and growth limits. The slow warming was applied from the ancestral temperature 37°C to total cell death 46–54°C: about 30 generations were propagated. Upper survival and growth limits for rapid warming (46°C) were lower than for slow warming (46–54°C). The thermal limit of survival for slow warming was higher for DPD3084 (50–54°C). Further experiments conducted on DPD3084, showed that mechanisms involved in this type of thermotolerance were abolished by a following cooling step to 37°C, which allowed to imply reversible mechanisms as acclimation ones. Acquisition of acclimation mechanisms was related to physical properties of the plasma membrane but was not inhibited by unavoidable appearance of aggregated proteins. In conclusion, E.coli could be rapidly acclimated within few generations over thermal limits described in the literature. Such a study led us to propose that rapid acclimation may give supplementary time to the species to acquire a stable adaptation through a random mutation. PMID:24357618

  5. A look-up-table digital predistortion technique for high-voltage power amplifiers in ultrasonic applications.

    PubMed

    Gao, Zheng; Gui, Ping

    2012-07-01

    In this paper, we present a digital predistortion technique to improve the linearity and power efficiency of a high-voltage class-AB power amplifier (PA) for ultrasound transmitters. The system is composed of a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), and a field-programmable gate array (FPGA) in which the digital predistortion (DPD) algorithm is implemented. The DPD algorithm updates the error, which is the difference between the ideal signal and the attenuated distorted output signal, in the look-up table (LUT) memory during each cycle of a sinusoidal signal using the least-mean-square (LMS) algorithm. On the next signal cycle, the error data are used to equalize the signal with negative harmonic components to cancel the amplifier's nonlinear response. The algorithm also includes a linear interpolation method applied to the windowed sinusoidal signals for the B-mode and Doppler modes. The measurement test bench uses an arbitrary function generator as the DAC to generate the input signal, an oscilloscope as the ADC to capture the output waveform, and software to implement the DPD algorithm. The measurement results show that the proposed system is able to reduce the second-order harmonic distortion (HD2) by 20 dB and the third-order harmonic distortion (HD3) by 14.5 dB, while at the same time improving the power efficiency by 18%.

  6. Transvaginal 3-d power Doppler ultrasound evaluation of the fetal brain at 10-13 weeks' gestation.

    PubMed

    Hata, Toshiyuki; Tanaka, Hirokazu; Noguchi, Junko

    2012-03-01

    The objective of this study was to measure the fetal brain volume (FBV) and vascularization and blood flow using transvaginal 3-D power Doppler (3DPD) ultrasound late in the first trimester of pregnancy. 3DPD ultrasound examinations with the VOCAL imaging analysis program were performed on 36 normal fetuses from 10-13 weeks' gestation. FBV and 3DPD indices related to the fetal brain vascularization (vascularization index [VI], flow index [FI] and vascularization flow index [VFI]) were calculated in each fetus. Intra- and interclass correlation coefficients and intra- and interobserver agreements of measurements were assessed. FBV was curvilinearly correlated well with the gestational age (R2 = 0.861, p < 0.0001). All 3-D power Doppler indices (VI, FI and VFI) showed no change at 10-13 weeks' gestation. FBV and all 3-D power Doppler indices (VI, FI and VFI) showed a correlation > 0.82, with good intra- and interobserver agreement. Our findings suggest that 3-D ultrasound is a superior means of evaluating the FBV in utero, and that 3-D power Doppler ultrasound histogram analysis may provide new information on the assessment of fetal brain perfusion.

  7. Bone Remodeling Monitor

    NASA Technical Reports Server (NTRS)

    Foucar, Charlie; Goldberg, Leslie; Hon, Bodin; Moore, Shannon; Williams, Evan

    2009-01-01

    The impact of bone loss due to different mechanical loadings in microgravity is a major concern for astronauts upon reintroduction to gravitational forces in exploration missions to the Moon and Mars. it has been shown that astronauts not only lose bone at differing rates, with levels up to 2% per month, but each astronaut will respond to bone loss treatments differently. Pre- and post-flight imaging techniques and frozen urine samples for post-flight laboratory immunoassays To develop a novel, non-invasive, highly . sensitive, portable, intuitive, and low-powered device to measure bone resorption levels in 'real time' to provide rapid and Individualized feedback to maximize the efficacy of bone loss countermeasures 1. Collect urine specimen and analyze the level of bone resorption marker, DPD (deoxypridinoline) excreted. 2. Antibodies specific to DPD conjugated with nanoshells and mixed with specimen, the change in absorbance from agglutination is measured by an optical device. 3. The concentration of DPD is displayed and recorded on a PDA

  8. Ventrolateral prefrontal cortex repetitive transcranial magnetic stimulation in the treatment of depersonalization disorder: A consecutive case series.

    PubMed

    Jay, Emma-Louise; Nestler, Steffen; Sierra, Mauricio; McClelland, Jessica; Kekic, Maria; David, Anthony S

    2016-06-30

    Case reports and an open trial have reported promising responses to repetitive transcranial magnetic stimulation (rTMS) to prefrontal and temporo-parietal sites in patients with depersonalization disorder (DPD). We recently showed that a single session of rTMS to the ventrolateral prefrontal cortex (VLPFC) was associated with a reduction in symptoms and increase in physiological arousal. Seven patients with medication-resistant DSM-IV DPD received up to 20 sessions of right-sided rTMS to the VLPFC for 10 weeks. Stimulation was guided using neuronavigation software based on participants' individual structural MRIs, and delivered at 110% of resting motor threshold. A session consisted of 1Hz repetitive TMS for 15min. The primary outcome measure was reduction in depersonalization symptoms on the Cambridge Depersonalization Scale (CDS). Secondary outcomes included scores on the Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI). 20 sessions of rTMS treatment to right VLPFC significantly reduced scores on the CDS by on average 44% (range 2-83.5%). Two patients could be classified as "full responders", four as "partial" and one a non-responder. Response usually occurred within the first 6 sessions. There were no significant adverse events. A randomized controlled clinical trial of VLPFC rTMS for DPD is warranted.

  9. Influence of carbon-based nanomaterials on lux-bioreporter Escherichia coli.

    PubMed

    Jia, Kun; Marks, Robert S; Ionescu, Rodica E

    2014-08-01

    The cytotoxic effects of carbon-based nanomaterials are evaluated via the induction of luminescent genetically engineered Escherichia coli bacterial cells. Specifically, two engineered E. coli bacteria strains of DPD2794 and TV1061 were incubated with aqueous dispersion of three carbon allotropes (multi-wall carbon nanotubes (MWCNTs), graphene nanosheets and carbon black nanopowders) with different concentrations and the resulting bioluminescence was recorded at 30°C and 25°C, respectively. The corresponding optical density changes of bacterial cells in the presence of various carbon nanomaterials were recorded as well. Based on these results, E. coli DPD2794 bacterial induction responds to a greater degree than E. coli TV1061 bacteria when exposed to various carbon-based nanomaterials. Finally, the surface morphology of E. coli DPD2794 bacteria cells before and after carbon-based nanomaterials treatment was observed using a field emission scanning electron microscope (FESEM), from which morphological changes from the presence of carbon-based nanomaterials were observed and discussed.

  10. Evaluation of TS-1 based treatment and expression of thymidylate synthase and dihydropyrimidine dehydrogenase on oral squamous cell carcinoma.

    PubMed

    Obara, Seiji; Yamamoto, Kazumi; Hosogai, Nao; Yoshimura, Yasuro

    2005-03-01

    Seventeen oral squamous cell carcinoma (SCC) patients underwent chemotherapy with TS-1 (8 males and 9 females, mean age; 75.1 years, range; 47-102 years). TS-1 permitted five cases of oral chemotherapy on an outpatient basis and 8 cases in elder patients over 80-years of age. Excepting five patients who underwent TS-1 therapy as post-operative adjuvant chemotherapy, the therapeutic efficacy of TS-1 in 12 patients with or without irradiation, surgery or chemotherapy resulted in 3 cases of complete response (CR), 6 cases of partial response (PR), 3 cases of stable disease (SD), with no progressive disease (PD) cases (overall response rate; 75%). SCC samples obtained from biopsy were immunohistochemically stained with anti-TS and DPD polyclonal antibody. Although the statistical significance was not clear, the expression of TS and DPD for CR cases was lower than that for SD cases. TS-1 therapy improved quality of life (QOL) especially in elder patients with oral SCC, and our immunohistochemical results suggested the predictive possibilities of TS and DPD expression in response to TS-1.

  11. Dissipative particle dynamics with attractive and repulsive particle-particle interactions

    SciTech Connect

    Paul Meakin; Moubin Liu; Hai Huang

    2006-01-01

    In molecular dynamics simulations, a combination of short-range repulsive and long-range attractive interactions allows the behavior of gases, liquids, solids, and multiphase systems to be simulated. We demonstrate that dissipative particle dynamics (DPD) simulations with similar pairwise particle-particle interactions can also be used to simulate the dynamics of multiphase fluids. In these simulations, the positive, short-range, repulsive part of the interaction potentials were represented by polynomial spline functions such as those used as smoothing functions in smoothed particle hydrodynamics, and the negative long-range part of the interaction has the same form but a different range and amplitude. If a single spline function corresponding to a purely repulsive interaction is used, the DPD fluid is a gas, and we show that the Poiseuille flow of this gas can be described accurately by the Navier-Stokes equation at low Reynolds numbers. In a two-component system in which the purely repulsive interactions between different components are substantially larger than the purely repulsive intracomponent interactions, separation into two gas phases occurs, in agreement with results obtained using DPD simulations with standard repulsive particle-particle interactions. Finally, we show that a combination of short-range repulsive interactions and long-range attractive interactions can be used to simulate the behavior of liquid drops surrounded by a gas. Similar models can be used to simulate a wide range of processes such as multiphase fluid flow through fractures and porous media with complex geometries and wetting behaviors.

  12. A Coarse-Grained Simulation of Rheology of Colloidal Suspensions and Polymer Nano-Composites

    NASA Astrophysics Data System (ADS)

    Pryamitsyn, Victor

    2005-03-01

    We extend DPD model to address dynamical properties of suspensions of solid particles in complex fluids. In this approach, the solvent particles (polymer segments) are represented as DPD particles. In contrast, the solute particles are represented as spherical hard particles of appropriate size. To provide proper shear friction and grip of the colloids and solvent we utilize Espanol's extensions over standard DPD model by adding rotational degree of freedom and rotational friction and non-central dissipative and random forces. For non-polymeric fluids, our results focus on the equilibrium dynamics and the steady state shear rheological behavior for a range of volume fractions of the suspension, and demonstrate excellent agreement with many published experimental and theoretical results. Moreover, we are also able to track the glass transition of our suspension and associated dynamical signatures in both the diffusivities and the rheological properties of our suspension. For polymeric fluid, we have studied influence of polymer-particle friction and particle concentration on polymer matrix relaxation dynamics, particle diffusion and rheology of the composite. Our results suggest that the simulation approach can be used as a mesoscale model to examine quantitatively the rheological properties of colloidal suspensions in complex fluid solvents such as polymeric melts and solutions, as well as allied dynamical phenomena such as phase ordering in mixtures of block copolymers and particles.

  13. Autoinducer 2: a concentration-dependent signal for mutualistic bacterial biofilm growth

    USGS Publications Warehouse

    Rickard, A.H.; Palmer, R.J.; Blehert, D.S.; Campagna, S.R.; Semmelhack, M.F.; Egland, P.G.; Bassler, B.L.; Kolenbrander, P.E.

    2006-01-01

    4,5-dihydroxy-2,3-pentanedione (DPD), a product of the LuxS enzyme in the catabolism of S-ribosylhomocysteine, spontaneously cyclizes to form autoinducer 2 (AI-2). AI-2 is proposed to be a universal signal molecule mediating interspecies communication among bacteria. We show that mutualistic and abundant biofilm growth in flowing saliva of two human oral commensal bacteria, Actinomyces naeslundii T14V and Streptococcus oralis 34, is dependent upon production of AI-2 by S. oralis 34. A luxS mutant of S. oralis 34 was constructed which did not produce AI-2. Unlike wild-type dual-species biofilms, A. naeslundii T14V and an S. oralis 34 luxS mutant did not exhibit mutualism and generated only sparse biofilms which contained a 10-fold lower biomass of each species. Restoration of AI-2 levels by genetic or chemical (synthetic AI-2 in the form of DPD) complementation re-established the mutualistic growth and high biomass characteristic for the wild-type dual-species biofilm. Furthermore, an optimal concentration of DPD was determined, above and below which biofilm formation was suppressed. The optimal concentration was 100-fold lower than the detection limit of the currently accepted AI-2 assay. Thus, AI-2 acts as an interspecies signal and its concentration is critical for mutualism between two species of oral bacteria grown under conditions that are representative of the human oral cavity. ?? 2006 Blackwell Publishing Ltd.

  14. Heritability of markers of bone metabolism

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.; Zwart, S. R.; Hargens, A. R.

    2005-01-01

    Several classic twin studies show genetic effects on markers of bone health, including bone mineral density and parathyroid hormone (PTH). This study was performed to assess the relative contribution of genetics to biochemical markers of bone metabolism. Fifteen sets of identical twins (8 male, 7 female) were housed in a clinical research center where diet was controlled (15% protein, 55% carbohydrate, 30% fat) for 3 consecutive days. Each day, 24-h urine pools were collected and N-telopeptide (NTX), deoxypyridinoline (DPD), calcium, and serum PTH were measured. The broad-sense heritability factor (H2) is an estimation of the portion of the total variance of a given phenotype that is attributable to genetic variance. H2 was estimated from the correlation coefficient of the phenotype data. H2 for NTX was 94% for males and 80% for females, DPD was 88% for males and 97% for females, urinary calcium excretion was 97% for males and 90% for females, and PTH was 92% for males and 79% for females. Since environmental variability was minimized for the 3 days of data collection, these heritability factors are likely overestimated. Nonetheless, the data support the concept that PTH is a predominantly heritable trait, and suggest that NTX, DPD, and calcium excretion are as well. These biochemical data support the previously documented heritability of bone health.

  15. Microstructure and annealing behavior of a modified 9Cr-1Mo steel after dynamic plastic deformation to different strains

    NASA Astrophysics Data System (ADS)

    Zhang, Z. B.; Mishin, O. V.; Tao, N. R.; Pantleon, W.

    2015-03-01

    The microstructure, hardness and tensile properties of a modified 9Cr-1Mo steel processed by dynamic plastic deformation (DPD) to different strains (0.5 and 2.3) have been investigated in the as-deformed and annealed conditions. It is found that significant structural refinement and a high level of strength can be achieved by DPD to a strain of 2.3, and that the microstructure at this strain contains a large fraction of high angle boundaries. The ductility of the DPD processed steel is however low. Considerable structural coarsening of the deformed microstructure without pronounced recrystallization takes place during annealing of the low-strain and high-strain samples for 1 h at 650 °C and 600 °C, respectively. Both coarsening and partial recrystallization occur in the high-strain sample during annealing at 650 °C for 1 h. For this sample, it is found that whereas coarsening alone results in a loss of strength with only a small gain in ductility, coarsening combined with pronounced partial recrystallization enables a combination of appreciably increased ductility and comparatively high strength.

  16. Parameterization of a mesoscopic model for the self-assembly of linear sodium alkyl sulfates

    NASA Astrophysics Data System (ADS)

    Mai, Zhaohuan; Couallier, Estelle; Rakib, Mohammed; Rousseau, Bernard

    2014-05-01

    A systematic approach to develop mesoscopic models for a series of linear anionic surfactants (CH3(CH2)n - 1OSO3Na, n = 6, 9, 12, 15) by dissipative particle dynamics (DPD) simulations is presented in this work. The four surfactants are represented by coarse-grained models composed of the same head group and different numbers of identical tail beads. The transferability of the DPD model over different surfactant systems is carefully checked by adjusting the repulsive interaction parameters and the rigidity of surfactant molecules, in order to reproduce key equilibrium properties of the aqueous micellar solutions observed experimentally, including critical micelle concentration (CMC) and average micelle aggregation number (Nag). We find that the chain length is a good index to optimize the parameters and evaluate the transferability of the DPD model. Our models qualitatively reproduce the essential properties of these surfactant analogues with a set of best-fit parameters. It is observed that the logarithm of the CMC value decreases linearly with the surfactant chain length, in agreement with Klevens' rule. With the best-fit and transferable set of parameters, we have been able to calculate the free energy contribution to micelle formation per methylene unit of -1.7 kJ/mol, very close to the experimentally reported value.

  17. Implementing Multiscale Fluid Simulations using Multiscale Universal Interface

    NASA Astrophysics Data System (ADS)

    Tang, Yu-Hang; Kudo, Shuhei; Bian, Xin; Li, Zhen; Karniadakis, George; Crunch Team

    2015-11-01

    The power of multiscale fluid simulations lies in its ability to recover a hierarchical levels of details by choreographing multiple solvers, thus extending the length and time scale accessible given a fixed amount of computing power. However, practical difficulties frequently arise when stitching together solvers which were not designed to be coupled, and would often result in tedious and unsustainable coding effort. The Multiscale Universal Interface (MUI) aims to solve this problem by exposing a small set of generalized programming interfaces that can be dropped into existing solvers with minimal intrusion. Three deployment cases will be given for demonstrating real-world applications of MUI. In the first case we used MUI to implement simulations of polymer-grafted surface in flow using Smoothed Particle Hydrodynamics/Dissipative Particle Dynamics (SPH/DPD) and state variable coupling. In the second case we constructed coupled DPD/Finite Element Method (FEM) simulation of conjugate heat transfer in heterogeneous coolant. In the third case we built hybrid DPD/molecular dynamics (MD) simulations by blending the forces on atoms at interface regions. Supported by the DOE Collaboratory on Mathematics for Mesoscopic Modeling of Materials (CM4) and AFOSR FA9550-12-1-0463. Computer hours at ORNL allocated through INCITE BIP118 and DD102.

  18. Complexity-reduced digital predistortion for subcarrier multiplexed radio over fiber systems transmitting sparse multi-band RF signals.

    PubMed

    Pei, Yinqing; Xu, Kun; Li, Jianqiang; Zhang, Anxu; Dai, Yitang; Ji, Yuefeng; Lin, Jintong

    2013-02-11

    A novel multi-band digital predistortion (DPD) technique is proposed to linearize the subcarrier multiplexed radio-over-fiber (SCM-RoF) system transmitting sparse multi-band RF signal with large blank spectra between the constituent RF bands. DPD performs on the baseband signal of each individual RF band before up-conversion and RF combination. By disregarding the blank spectra, the processing bandwidth of the proposed DPD technique is greatly reduced, which is only determined by the baseband signal bandwidth of each individual RF band, rather than the entire bandwidth of the combined multi-band RF signal. Experimental demonstration is performed in a directly modulated SCM-RoF system transmitting two 64QAM modulated OFDM signals on 2.4GHz band and 3.6GHz band. Results show that the adjacent channel power (ACP) is suppressed by 15dB leading to significant improvement of the EVM performances of the signals on both of the two bands.

  19. Mesoscopic Simulation Methods for Polymer Dynamics

    NASA Astrophysics Data System (ADS)

    Larson, Ronald

    2015-03-01

    We assess the accuracy and efficiency of mesoscopic simulation methods, namely Brownian Dynamics (BD), Stochastic Rotation Dynamics (SRD) and Dissipative Particle Dynamics (DPD), for polymers in solution at equilibrium and in flows in microfluidic geometries. Both SRD and DPD use solvent ``particles'' to carry momentum, and so account automatically for hydrodynamic interactions both within isolated polymer coils, and with other polymer molecules and with nearby solid boundaries. We assess quantitatively the effects of artificial particle inertia and fluid compressibility and show that they can be made small with appropriate choice of simulation parameters. We then use these methods to study flow-induced migration of polymer chains produced by: 1) hydrodynamic interactions, 2) streamline curvature or stress-gradients, and 3) convection of wall depletion zones. We show that huge concentration gradients can be produced by these mechanisms in microfluidic geometries that can be exploited for separation of polymers by size in periodic contraction-expansion geometries. We also assess the range of conditions for which BD, SRD or DPD is preferable for mesoscopic simulations. Finally, we show how such methods can be used to simulate quantitatively the swimming of micro-organisms such as E. coli. In collaboration with Lei Jiang and Tongyang Zhao, University of Michigan, Ann Arbor, MI.

  20. Sodium zeolite a supplementation and its impact on the skeleton of dairy calves.

    PubMed

    Turner, K K; Nielsen, B D; O'Connor-Robison, C I; Rosenstein, D S; Marks, B P; Nielsen, F H; Orth, M W

    2008-02-01

    Twenty calves were placed on study at 3 days of age and were placed according to birth order into one of two groups: SS, which received 0.05% BW sodium zeolite A (SZA) added to their milk replacer, and CO, which received only milk replacer. Blood samples were taken on days 0, 30, and 60 for osteocalcin (OC) and deoxypyridinoline (DPD) analysis. On day 60, the calves were euthanized, and synovial fluid, articular cartilage, and both fused metacarpals were collected for bone quality analyses such as architecture and mechanical properties, mineral composition, and glycosaminoglycan concentration. There were no differences in OC concentrations because of treatment (p = 0.12), and CO calves had lower DPD concentrations than SS calves (p = 0.01), but the OC-to-DPD ratio was not different between treatments (p = 0.98). No differences in bone architecture or mechanical properties were detected. SZA supplementation increased cortical bone (p = 0.0002) and articular cartilage (p = 0.05) aluminum content. Glycosaminoglycan concentrations were not different in synovial fluid or cartilage. Supplementation of SZA appeared to alter the rate of bone turnover without altering bone strength. Aluminum concentrations in the bone and cartilage increased, which may be a concern, although the long-term consequences of such remain to be determined.

  1. Application of Berendsen barostat in dissipative particle dynamics for nonequilibrium dynamic simulation.

    PubMed

    Lin, Yuqing; Pan, Dingyi; Li, Jiaming; Zhang, Lingxin; Shao, Xueming

    2017-03-28

    The Berendsen barostat from molecular dynamics simulation is applied in both standard dissipative particle dynamics (DPD) and many-body dissipative particle dynamics (MDPD) simulations. The original Berendsen barostat works well in (M)DPD simulation of a single-component system under constant pressure condition and in nonequilibrium dynamic processes. The partial Berendsen barostat is proposed for multi-component system simulation with (M)DPD. The displacement rescaling process of the Berendsen barostat is only applied on the particles outside the center region, acting as a pressure "boundary condition." The center part forms the free zone, in which the interface shape and nonequilibrium dynamic behavior between different phases can be captured properly. An immiscible bubble in the second fluid under constant pressure condition is studied, and the oscillation of the bubble radius and fluctuation of systempressure can be obtained by the current barostat. Preliminary models for bubble growing and collapsing under square pressure wave and bubble oscillation under harmonic pressure wave are also reported in the current simulation. It shows that the partial Berendsen barostat is suitable for the modeling of nonequilibrium process of single or few droplets/bubbles in multi-component systems.

  2. A critical comparison of two high-throughput ascorbate analyses methods for plant samples.

    PubMed

    Ueda, Yoshiaki; Wu, Linbo; Frei, Michael

    2013-09-01

    Ascorbate (AsA) is an important metabolite involved in stress response and development of plants. Therefore it is necessary to quantify the AsA content in many fields of plant science, including high throughput and critical applications. In this study we compared two different microplate-based AsA assays, which are suitable for high throughput applications: an ascorbate oxidase (AO)-based assay and a dipyridyl (DPD)-based assay. These methods were compared in critical applications, i.e. (i) when AsA concentrations were very low such as in apoplastic extracts, (ii) when plants contained pigments interfering with the spectrometric measurements, and (iii) when plants contained high iron concentration interfering with the color reactions. The precision of measurements was higher with the DPD method, as illustrated by higher recovery rates of internal AsA standards. On the other hand, the AO method was more sensitive to low levels of AsA. This was an advantage in determining apoplastic AsA concentration in rice, which was substantially lower than that of whole tissues. The AO method also had the advantage that plant pigments and high iron concentrations in plants tissues did not interfere with the analysis, as opposed to the DPD assay. In conclusion, both assays had advantages and the choice of a suitable method depends on the specific application.

  3. Quantitative analysis of the enzymes associated with 5-fluorouracil metabolism in prostate cancer biopsies.

    PubMed

    Tanaka, Tomoaki

    2011-01-01

    Orotate phosphoribosyl transferase (OPRT) is the initial enzyme of 5-FU activation, in which 5-FU is converted to 5-fluorouridinemonophosphate. Dihydropyrimidine dehydrogenase (DPD) is a degrading enzyme that catabolizes 5-FU. In this study, we investigated the expression of these enzymes in normal prostate gland (NP), hormone-sensitive prostate cancer (HSPC), and hormone-refractory prostate cancer (HRPC). The prostatic tissue specimens were obtained from patients who had undergone prostate needle biopsies without any treatments or with PSA failure after initial androgen deprivation. The tissue samples derived from formalin-fixed, paraffin-embedded (FFPE) sections were prepared by laser-capture microdissection, and from them RNA was extracted. The levels of OPRT and DPD mRNA expression were examined by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). The level of OPRT mRNA expression in the HSPC or the HRPC specimens was significantly higher than that in the NP specimens. There was a significant correlation between OPRT mRNA expression levels and the tumor pathological grade. Furthermore, the OPRT/ DPD expression ratio, a powerful predictive factor to evaluate 5-FU sensitivity, in the HRPC group was significantly higher than that in the low-grade HSPC group. Thus, the quantitative evaluation for these enzymes based on phosphorylation of 5-FU may be an effective option for some prostate cancer patients, particularly HRPC group.

  4. Overexpression of orotate phosphoribosyl transferase in hormone-refractory prostate cancer.

    PubMed

    Tanaka, Tomoaki; Kawashima, Hidenori; Matsumura, Kentaro; Yamashita-Hosono, Tomoko; Yoshimura, Rikio; Kuratsukuri, Katsuyuki; Harimoto, Koji; Nakatani, Tatsuya

    2009-01-01

    Orotate phosphoribosyl transferase (OPRT) is the initial enzyme of 5-fluorouracil (5-FU) activation, in which 5-FU is converted to 5-fluorouridinemonophosphate. Dihydropyrimidine dehydrogenase (DPD) is a degrading enzyme that catabolizes 5-FU. In this study, we investigated the expression of these enzymes in normal prostate gland (NP), hormone-sensitive prostate cancer (HSPC) and hormone-refractory prostate cancer (HRPC). Forty-two prostatic tissue specimens were obtained from patients who had undergone prostate needle biopsies without any treatments or with PSA failure after initial androgen deprivation. The tissue samples derived from formalin-fixed, paraffin-embedded sections were made by laser-captured microdissection and from those RNA was extracted. The levels of OPRT and DPD mRNA expression were examined by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). The level of OPRT mRNA expression in the HSPC or the HRPC specimens was significantly higher than that in the NP specimens. Immunohistochemical staining for OPRT revealed strong expression of OPRT in prostate cancer cells. There was a significant correlation between OPRT mRNA expression levels and the tumor pathological grade. Furthermore, the OPRT/DPD expression ratio, a powerful predictive factor to evaluate 5-FU sensitivity, in the HRPC group was significantly higher than that in the low grade HSPC group. Thus, 5-FU may be an effective option for some HRPC patients.

  5. Decision peptide-driven: a free software tool for accurate protein quantification using gel electrophoresis and matrix assisted laser desorption ionization time of flight mass spectrometry.

    PubMed

    Santos, Hugo M; Reboiro-Jato, Miguel; Glez-Peña, Daniel; Nunes-Miranda, J D; Fdez-Riverola, Florentino; Carvallo, R; Capelo, J L

    2010-09-15

    The decision peptide-driven tool implements a software application for assisting the user in a protocol for accurate protein quantification based on the following steps: (1) protein separation through gel electrophoresis; (2) in-gel protein digestion; (3) direct and inverse (18)O-labeling and (4) matrix assisted laser desorption ionization time of flight mass spectrometry, MALDI analysis. The DPD software compares the MALDI results of the direct and inverse (18)O-labeling experiments and quickly identifies those peptides with paralleled loses in different sets of a typical proteomic workflow. Those peptides are used for subsequent accurate protein quantification. The interpretation of the MALDI data from direct and inverse labeling experiments is time-consuming requiring a significant amount of time to do all comparisons manually. The DPD software shortens and simplifies the searching of the peptides that must be used for quantification from a week to just some minutes. To do so, it takes as input several MALDI spectra and aids the researcher in an automatic mode (i) to compare data from direct and inverse (18)O-labeling experiments, calculating the corresponding ratios to determine those peptides with paralleled losses throughout different sets of experiments; and (ii) allow to use those peptides as internal standards for subsequent accurate protein quantification using (18)O-labeling. In this work the DPD software is presented and explained with the quantification of protein carbonic anhydrase.

  6. An automatic falling drop system based on multicommutation process for photometric chlorine determination in bleach.

    PubMed

    da Silva Borges, Sivanildo; Reis, Boaventura F

    2007-09-26

    In this work an automatic photometric procedure for the determination of chlorine in bleach samples employing N,N'-diethyl-p-phenylenediamine (DPD) as chromogenic reagent is described. The procedure was based on a falling drop system where the analyte (Cl(2)) was collected by a DPD solution drop (50 microL) after its delivery from the sample bulk that was previously acidified. The flow system was designed based on the multicommutation process assembling a set of three-way solenoid valves, which under microcomputer control afforded facilities to handle sample and reagent solution in order to control analyte delivering and solution drop generation. The analyte volatilization was improved by coupling online a little heating device. The detection system comprised a green LED (515 nm) and a phototransistor. Aiming to prove the usefulness of the proposed procedure a set of bleach samples was analyzed. Comparing the results with those obtained with reference method no significant difference at 95% confidence level was observed. Other profitable features such as a linear response ranging from 15 up to 100 mgL(-1) Cl(2) (R=0.999); a detection limit of 4.5 mgL(-1) Cl(2) estimated based on the 3 sigma criterion; a relative standard deviation of 2.5% (n=10) using a typical bleach sample containing 25.0 mgL(-1) Cl(2); a consumption of 55 microg of DPD per determination; and a analytical frequency of 20 determinations per hour were also achieved.

  7. Triple-decker: Interfacing atomistic-mesoscopic-continuum flow regimes

    SciTech Connect

    Fedosov, Dmitry A.; Karniadakis, George Em

    2009-03-01

    Multiscale flow phenomena in microfluidic and biomedical applications require the use of heterogeneous modeling approaches. In this paper we present a hybrid method based on coupling the Molecular Dynamics (MD) method, the Dissipative Particle Dynamics (DPD) method, and the incompressible Navier-Stokes (NS) equations. MD, DPD, and NS are formulated in separate subdomains and are coupled via an overlapping region by communicating state information at the subdomain boundaries. Imposition of boundary conditions in the MD and DPD systems involves particle insertion and deletion, specular wall reflection and body force terms. The latter includes a boundary pressure force in order to minimize near-boundary density fluctuations, and an adaptive shear force which enforces the tangential velocity component of boundary conditions. The triple-decker algorithm is verified for prototype flows, including simple and multi-layer fluids (Couette, Poiseuille, and lid-driven cavity), using highly accurate reference solutions. A zero-thickness interface is also possible if it is aligned with the flow streamlines.

  8. Heritability of markers of bone metabolism

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.; Zwart, S. R.; Hargens, A. R.

    2005-01-01

    Several classic twin studies show genetic effects on markers of bone health, including bone mineral density and parathyroid hormone (PTH). This study was performed to assess the relative contribution of genetics to biochemical markers of bone metabolism. Fifteen sets of identical twins (8 male, 7 female) were housed in a clinical research center where diet was controlled (15% protein, 55% carbohydrate, 30% fat) for 3 consecutive days. Each day, 24-h urine pools were collected and N-telopeptide (NTX), deoxypyridinoline (DPD), calcium, and serum PTH were measured. The broad-sense heritability factor (H2) is an estimation of the portion of the total variance of a given phenotype that is attributable to genetic variance. H2 was estimated from the correlation coefficient of the phenotype data. H2 for NTX was 94% for males and 80% for females, DPD was 88% for males and 97% for females, urinary calcium excretion was 97% for males and 90% for females, and PTH was 92% for males and 79% for females. Since environmental variability was minimized for the 3 days of data collection, these heritability factors are likely overestimated. Nonetheless, the data support the concept that PTH is a predominantly heritable trait, and suggest that NTX, DPD, and calcium excretion are as well. These biochemical data support the previously documented heritability of bone health.

  9. Simulation analysis of directed self-assembly for hole multiplication in guide pattern

    NASA Astrophysics Data System (ADS)

    Muramatsu, M.; Nakano, T.; Tomita, T.; Yamamoto, K.; Matsuzaki, K.; Kitano, T.

    2014-03-01

    In this report, morphology of cylinders by block copolymer (BCP) in the corner rounded rectangle guide patterns is analyzed by simulation and compared with experimental results. In the case of the hole-multiplication, selection the guide pattern size and the affinity of wall and under layer is necessary for stable micro structure. To search the good guide conditions, Ohta-Kawasaki (OK) model and dissipative particle dynamics (DPD) are used. OK model is well known as low cost simulation method, therefore it is expected to use for searching the good guide area roughly from wide range. DPD is one of the strong candidates for DSA simulation, and it is used for prediction of the micro structure. As results, the guide size area which has two PMMA cylinders by 2D OK model seems consistent with experimental results, 3D micro structure by OK model and DPD are comparable, 3D simulations have good agreements with experimental results observed by CD-SEM and STEM. Especially two cylinders connected each other at some point predicted by 3D simulation is observed actually. These simulation approaches will be important to decide the lithography mask design, film stack and pre-treatment conditions for more complex multiplication process, for example, the cut mask application.

  10. A retrospective study on TS mRNA expression and prediction of the effects of adjuvant oral 5-fluorouracil in breast cancer

    PubMed Central

    AKI, FUMINORI; BANDO, YOSHIMI; TAKAHASHI, TETSUYUKI; UEHARA, HISANORI; NUMOTO, SATOSHI; ITO, SUEYOSHI; SASA, MITSUNORI; IZUMI, KEISUKE

    2010-01-01

    Nucleic acid-metabolizing enzymes, such as thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP) and orotate phosphoribosyl transferase (OPRT), have attracted attention as candidates for response determinants of 5-fluorouracil (5-FU). Whether the expression levels of these enzymes can be adopted as valuable parameters for 5-FU sensitivity in breast cancer has yet to be elucidated. In the present study, intratumoral mRNA expression of TS, DPD, TP and OPRT were determined in formalin-fixed paraffin-embedded surgical specimens collected from 217 breast cancer patients, using the Danenberg Tumor Profile method, which combines microdissection and real-time-polymerase chain reaction. The significance of these enzymes as prognostic and 5-FU efficacy-predicting factors was evaluated. Our data showed that a low DPD expression is related to a high nuclear grade and other factors including hormone receptor-negativity. Low expression levels of TP were found in hormone receptor-negative tumors. TS and OPRT expression were not related to various clinicopathological factors, but patients with a high TS mRNA expression showed a significantly poorer prognosis in cases where 5-FU was not administered. The efficacy of 5-FU was more significant when administered for more than 6 months in the group with a high TS mRNA expression. These data suggest that TS mRNA expression in breast cancer tissue is an ideal predictor of outcomes for patients with no administration of 5-FU, and of the efficacy of 5-FU. PMID:22870098

  11. Evidence of Increased Bone Resorption in Neurofibromatosis Type 1 Using Urinary Pyridinium Crosslink Analysis

    PubMed Central

    STEVENSON, DAVID A.; SCHWARZ, ELISABETH L.; VISKOCHIL, DAVID H.; MOYER-MILEUR, LAURIE J.; MURRAY, MARY; FIRTH, SEAN D.; D’ASTOUS, JACQUES L.; CAREY, JOHN C.; PASQUALI, MARZIA

    2011-01-01

    Although neurofibromatosis type 1 (NF1) is a neuro-cutaneous disorder, skeletal abnormalities such as long-bone dysplasia, scoliosis, sphenoid wing dysplasia, and osteopenia are observed. To investigate the role of bone resorption as a mechanism for the bony abnormalities, we selected urinary pyridinium crosslinks (collagen degradation products excreted in urine) as a measure of bone resorption in NF1. Bone resorption was evaluated by quantitative assessment of the urinary excretion of pyridinium crosslinks [pyridinoline (Pyd) and deoxypyridinoline (Dpd)]. Total (free plus peptide-bound) pyridinium crosslinks from the first morning urines from 59 NF1 children (ages 5–19) were extracted and analyzed (17 children with a localized skeletal dysplasia, and 42 without). The data were compared with a healthy reference population without NF1 (n = 99). Multivariate analyses, controlling for age showed statistically significant increases for Dpd (p < 0.001) and the Dpd/Pyd ratio (p < 0.001) in NF1 individuals with and without a skeletal dysplasia. NF1 children have an increase in the urinary excretion of pyridinium crosslinks, reflecting increased bone resorption. The effects of NF1 haploinsufficiency likely contribute to abnormal bone remodeling, either directly or indirectly by aberrant Ras signaling, potentially predisposing NF1 individuals to localized skeletal defects. PMID:18317233

  12. Analysis of structure and dynamics of superfine polyhydroxybutyrate fibers for targeted drug delivery

    NASA Astrophysics Data System (ADS)

    Olkhov, A.; Kucherenko, E.; Pantyukhov, P.; Zykova, A.; Karpova, S.; Iordanskii, A.

    2017-02-01

    Creation of polymer matrix systems for targeted drug delivery into a living organism is a challenging problem of modern treatment of various diseases and injuries. Poly-3-hydroxybutyrate (PHB) is commonly used for development of therapeutic systems. The aim of this article is to examine the changes in structure and morphology of fibers in presence of dipyridamole (DPD) as model drug for controlled release. It was found that addition of dipyridamole led to disappearance of spindle-shaped nodules on fibers of PHB in comparison with pure PHB. The research of thermophysical parameters showed that specific melting enthalpy (and the degree of crystallinity) of PHB fibers increased with the addition of DPD. With the increasing of DPD content in PHB fibers, more perfect and equilibrium crystal structure was formed. According to analysis of intercrystalline regions of PHB fibers, it was found that as the crystallinity of PHB in intergranular regions rose, the corresponding decrease of radical rotation speed was observed. It was concluded that fibers of PHB can be used for creating therapeutic systems for targeted and prolonged drug delivery.

  13. THE EFFECT OF PROBIOTIC FERMENTED MILK THAT INCLUDES BIFIDOBACTERIUM LACTIS CNCM I-2494 ON THE REDUCTION OF GASTROINTESTINAL DISCOMFORT AND SYMPTOMS IN ADULTS: A NARRATIVE REVIEW.

    PubMed

    Waitzberg, Dan L; Quilici, Flávio A; Michzputen, Sender; Friche Passos, Maria do Carmo

    2015-08-01

    Objetivo: determinar la eficacia de la leche fermentada con Bifidobacterium lactis CNCM I-2429 en la reducción de el malestar gastrointestinal (GI) en adultos sanos. Métodos: se realizó una búsqueda sistemática en la literatura para identificar estudios que informaron del uso de B. animalis spp. lactis para molestias/ confort GI en adultos sanos. Se identificaron un total de 5.329 registros, de estos se evaluaron 99 artículos de texto completo. Las búsquedas de ensayos adicionales se realizaron utilizando los nombres de los autores de cada estudio identificado y varias bases de datos relevantes. La selección de los estudios se llevó a cabo de acuerdo con las guías de Artículos de Información Preferidos para Revisiones Sistemáticas y Meta-Análisis (PRISMA). Los estudios eran incluidos si eran ensayos randomizados controlados, si los sujetos de estudio eran adultos sanos y si el grupo de intervención recibió B. lactis CNCM I-2494. Se excluyeron los estudios que no eran randomizados, que incluían adultos que no estaban sanos, que incluían el uso de cualquier otra intervención o si comparaban diferentes productos sin un grupo placebo. La calidad metodológica de los estudios se evaluó utilizando la Escala de Calidad de Oxford y la Evaluación Cochrane de ocultamiento. No fue posible un metaanálisis. Resultados: la estrategia de búsqueda identificó dos estudios que incluyeron un total de 538 mujeres sanas, con edades entre 18 a 60 años, de peso normal o sobrepeso (IMC de 18-30 kg/m2). En uno de los estudios las molestias GI disminuyeron significativamente en el grupo de probióticos frente al grupo control, sin diferencias en el otro. El porcentaje de respondedores para el bienestar GI fue mayor en el grupo de probióticos frente al grupo control en el primer estudio, pero no en el segundo. Los síntomas GI se redujeron significativamente en el grupo probiótico frente al grupo control en ambos estudios. La función intestinal solo se evaluó en

  14. Alfabetización en Astronomía de docentes de Educación Primaria y de Educación Secundaria en La Plata

    NASA Astrophysics Data System (ADS)

    De Biasi, M. S.; Orellana, R. B.

    2014-10-01

    La educación de este siglo tiene como uno de sus retos alcanzar la alfabetización cientfica de todos los ciudadanos para que comprendan y tomen decisiones sobre el mundo natural y sus cambios originados por la actividad humana utilizando el conocimiento científico. En esta misión los docentes de los niveles obligatorios de enseñanza juegan un papel clave por su rol de agentes multiplicadores del conocimiento. Se requiere, entonces de una adecuada alfabetización en ciencias de los docentes o, como mínimo, que dominen los temas científicos a enseñar. En el campo de la Astronomía, numerosas investigaciones han señalado que maestros de primaria y estudiantes de profesorados poseen una escasa formación en estos temas (Camino 1995 y 1999, Gangui 2010), que frecuentemente presentan a los alumnos concepciones alternativas o no científicas de los fenómenos astronómicos cotidianos (Kriner 2004, Vega Navarro 2007, Gangui et al 2010); a lo que se suma la presentación confusa o errónea de algunos temas astronómicos en los textos escolares (Kriner 2004). Desde 2011, la Facultad de Ciencias Astronómicas y Geofísicas, UNLP, ofrece un curso de capacitación destinado a fortalecer y actualizar los contenidos académicos y didácticos de los docentes del distrito La Plata utilizando diversas estrategias didácticas. Los contenidos comprenden los temas astronómicos de los diseños curriculares vigentes. La evaluación diagnóstica de los conocimientos previos de los docentes cursantes sobre los contenidos de mayor presencia en los diseños curriculares mostró resultados similares a las investigaciones arriba mencionadas. Referente a los movimientos de la Tierra, en promedio, el 54% poseía conceptos erróneos y el 16% no los sabía; con referencia a la Luna el 56% poseía conceptos erróneos y un 4% no los sabía. Los resultados del curso mostraron que el 95% de los docentes revirtió sus conceptos previos erróneos, que adquirió criterios para la búsqueda de

  15. Presentación del estudio "Links" de hombres que tienes sexo con hombres en Buenos Aires, Argentina.

    PubMed

    Carballo-Diéguez, Alex; Avila, María M; Balán, Iván C; Marone, Rubén; Pando, María A; Barreda, Victoria

    2011-03-01

    Estudios previos en Buenos Aires reportaron altas prevalencias de HIV entre HSH, con valores que oscilan entre 9 y 14% durante casi 10 años de continuo testeo. El objetivo principal de este estudio fue la evaluación de factores relacionados al comportamiento de alto riesgo para transmisión del HIV entre HSH entre los que se incluyen el conocimiento y factores emocionales, socioculturales y ambientales. Por otro lado se realizó la estimación de prevalencia e incidencia de HIV utilizando RDS (Respondent Driven Sampling), así como la presencia de otras infecciones de transmisión sexual. Por último se evaluaron los hábitos de testeo para HIV indagando que factores facilitan o impiden su realización. El estudio constó de dos fases, en primer lugar una fase cualitativa y posteriormente una fase cuantitativa con una duración total de 4 años y medio. Durante la fase cualitativa se realizaron 44 entrevistas individuales en profundidad, 8 grupos focales y 10 observaciones etnográficas (hoteles, baños públicos ("teteras"), cines pornográficos, fiestas privadas, dark rooms y discotecas). Durante la fase cuantitativa del estudio se realizó el reclutamiento de 500 participantes que provinieron de la Ciudad Autónoma de Buenos Aires, así como del Gran Buenos Aires. El reclutamiento se comenzó con 16 participantes llamados semillas. Se realizó el diagnóstico de infección por HIV, hepatitis B y C (HBV y HCV), Treponema pallidum, Virus Papiloma Humano (HPV) y Chlamidias. La colaboración establecida entre los grupos de trabajo enfocados en áreas diversas posibilitó el abordaje conjunto de nuevas estrategias de investigación antes no exploradas en nuestro país. Los resultados más relevantes de esta investigación serán progresivamente publicados en sucesivos números de Actualizaciones en SIDA.

  16. [EFFECTS OF INGESTING CARBOHYDRATE-PROTEIN SUPPLEMENTS DURING EXERCISE ON ENDURANCE PERFORMANCE: A SYSTEMATIC REVIEW].

    PubMed

    Espino-González, Ever; Muñoz-Daw, María de Jesús; Candia-Lujan, Ramon

    2015-11-01

    Introducción: las bebidas deportivas ayudan a mejorar el rendimiento físico de forma significativa debido a su aporte de carbohidratos, electrolitos y agua. Sin embargo, en las últimas décadas se ha encontrado que ingerir una bebida deportiva con proteína durante el ejercicio mejora el rendimiento físico, produce menores pérdidas de peso corporal inducidas por la deshidratación y ayuda a disminuir el daño muscular postejercicio en comparación con una bebida únicamente con carbohidratos y electrolitos. Objetivo: analizar los principales estudios sobre la efectividad de la ingesta de un suplemento con carbohidratos, proteína y electrolitos durante el ejercicio. Método: se realizó una búsqueda automatizada en Google académico, EBSCO, PubMEd y Scopus, utilizando las palabras clave: Carbohydrate-protein and performance y Added protein and sports drink. Se evaluó la calidad metodológica de los ensayos y se tomó en cuenta que la ingesta del suplemento fuera durante el ejercicio. Resultados: de los veinte artículos que se incluyeron, trece obtuvieron resultados en los que la ingesta de una bebida deportiva con proteína generó mejoras significativas en el rendimiento físico en comparación con una bebida únicamente con carbohidratos y electrolitos, o un placebo. Discusión: aumentar el contenido calórico de las bebidas deportivas al agregar proteína es probablemente una estrategia más efectiva en comparación con disminuir el contenido de carbohidratos para igualar la cantidad de energía. Conclusiones: el consumo de proteína durante el ejercicio posiblemente sirva como una ayuda ergogénica, retardando el tiempo hasta llegar al agotamiento. Sin embargo, hace falta más evidencia que así lo demuestre.

  17. Comunicación de pareja y VIH en mujeres en desventaja social

    PubMed Central

    Rosina Cianelli, A.; Lilian Ferrer, L.; Margarita Bernales, S.; Natalia Villegas, R.

    2009-01-01

    Introducción La epidemia de VIH y SIDA se ha diseminado rápidamente a nivel mundial tendiendo a la feminización, pauperización y heterosexualización. La comunicación de pareja en torno el VIH es descrita como uno de los factores protectores en la adquisición de esta enfermedad, favoreciendo la adopción de conductas sexuales seguras tales como la negociación de pareja y la utilización de preservativo, consideróndose como un pilar fundamental en la incorporación de medidas de autocuidado en la sexualidad femenina. Objetivo Determinar el nivel de comunicación de pareja en torno al VIH en mujeres chilenas en desventaja social. Metodología Cuatrocientas noventa y seis mujeres contestaron la entrevista inicial de la investigación “Testing an HIV/AIDS Prevention Intervention for Chilean Women” (RO1 TW 006977 PI Cianelli). Se utilizó la escala “Health protective sexual communication scale (HPC)” (0–10 puntos). Se realizó un análisis descriptivo utilizando el programa SPSS 16.0. Resultados El promedio del nivel de comunicación de pareja fue de 3,26 ± 2,7 puntos con la pareja principal, de 2,52 ± 2,48 puntos con una segunda pareja y de 0 puntos con una tercera pareja. Los temas de menor comunicación entre las parejas fueron el uso de preservativo y la realización del test para VIH antes de tener relaciones sexuales. Conclusión Las mujeres de la muestra presentan bajos niveles de comunicación de pareja en relación a VIH con todas sus parejas sexuales. Son necesarias estrategias que potencien este tópico dentro de las intervenciones de prevención de VIH y SIDA de manera de fortalecer la adopción de conductas de autocuidado en torno al tema. PMID:19936328

  18. Anthropometric indicators of obesity as predictors of cardiovascular risk in the elderly.

    PubMed

    Vidal Martins, Marcos; Queiroz Ribeiro, Andréia; Martinho, Karina Oliveira; Silva Franco, Fernanda; Danésio de Souza, Jacqueline; Bacelar Duarte de Morais, Keila; Gonçalves Leite, Isabel Cristina; Araújo Tinôco, Adelson Luiz

    2015-06-01

    Introducción: diversos indicadores antropométricos se pueden utilizar como predictores de riesgo cardiovascular en los ancianos. Objetivo: evaluar la capacidad predictiva de las medidas antropométricas en la identificación de riesgo cardiovascular en pacientes ancianos en la Estrategia Salud de la Familia de Viçosa-MG. Metodología: se realizó un estudio epidemiológico transversal con 349 ancianos. El riesgo cardiovascular se calculó mediante la relación de los niveles de triglicéridos con niveles de HDL-colesterol (TG / HDL-c). Las variables antropométricas medidas fueron: circunferencia de la cintura, índice de masa corporal, relación cintura-altura e índice de conicidad. Se realizó una evaluación bioquímica de triglicéridos y HDL-colesterol. Las mediciones antropométricas también estaban relacionados con el riesgo cardiovascular utilizando la característica (ROC) Curvas Receiver Operating. Resultados: los resultados observados indican que todos estos índices antropométricos se pueden usar para predecir el riesgo cardiovascular en los hombres. Sin embargo, en las mujeres, solo el IMC mostró capacidad predictiva. Los puntos de corte identificados aparecieron muy cerca de los puntos de corte recomendados y reconocidos en otros estudios, con la excepción de la circunferencia de la cintura, que se mide en el punto medio entre la última costilla y la cresta ilíaca, que mostró una diferencia considerable. Conclusión: todos los índices antropométricos se pueden usar para predecir el riesgo cardiovascular en hombres y mujeres. La circunferencia de la cintura en el punto medio entre la última costilla y la cresta ilíaca era la mejor medida antropométrica para predecir el riesgo cardiovascular en los varones y la circunferencia de cintura más pequeña y cintura-altura fueron las mejores medidas antropométricas en las mujeres.

  19. [STRATEGIES TO IMPROVE THE NUTRITIONAL AND HEALTH CHARACTERISTICS OF MEAT PIE OF MURCIA].

    PubMed

    Ruiz-Cano, Domingo; Zamora, Salvador; Frutos, María José; López-Jiménez, José Ángel; Pérez-Llamas, Francisca

    2015-12-01

    Objetivos: mejorar la composición nutritiva y las características saludables del pastel de carne de Murcia (PCM), manteniendo sus apreciadas cualidades organolépticas y el diseño de un PCM funcional, mediante la adición de un ingrediente natural rico en fuctooligosacáridos. Métodos: mediante cambios relacionados con el tipo y cantidad de algunos de sus ingredientes se han elaborado diversas formulaciones del PCM (PCM saludable y PCM funcional). Se ha determinado la composición nutritiva, el valor calórico, el perfil de ácidos grasos y la calidad de la grasa. Además, se han valorado diversos atributos sensoriales y la aceptación global utilizando una escala descriptiva hedónica de nueve puntos. Resultados y discusión: el PCM saludable presenta un menor contenido de energía (15,4%), grasa total (39%), grasa saturada (48%) y sal (45%), así como una disminución de la potencial capacidad aterogénica (27%), trombogénica (30%) e hipercolesterolémica (30%) que el PCM tradicional. De las cuatro cantidades ensayadas (2,5, 5, 10 y 15%), solo la sustitución del 2,5 y 5% del ingrediente funcional no disminuyeron la aceptación global del PCM funcional, en comparación con el PCM tradicional. Conclusiones: los cambios en la formulación han mejorado la composición nutritiva y las características saludables del PCM tradicional, manteniendo sus cualidades organolépticas. El PCM funcional, elaborado con el ingrediente funcional al 5%, representa una mejora factible en las características funcionales del alimento estudiado. Estas estrategias contribuyen a mantener este tipo de alimentos tradicionales y a evitar la pérdida en la cultura, identidad y herencia gastronómica de España en general y de la Región de Murcia en particular.

  20. Presentación del estudio “Links” de hombres que tienes sexo con hombres en Buenos Aires, Argentina

    PubMed Central

    Carballo-Diéguez, Alex; Ávila, María M; Balán, Iván C.; Marone, Rubén; Pando, María A.; Barreda, Victoria

    2011-01-01

    Resumen Estudios previos en Buenos Aires reportaron altas prevalencias de HIV entre HSH, con valores que oscilan entre 9 y 14% durante casi 10 años de continuo testeo. El objetivo principal de este estudio fue la evaluación de factores relacionados al comportamiento de alto riesgo para transmisión del HIV entre HSH entre los que se incluyen el conocimiento y factores emocionales, socioculturales y ambientales. Por otro lado se realizó la estimación de prevalencia e incidencia de HIV utilizando RDS (Respondent Driven Sampling), así como la presencia de otras infecciones de transmisión sexual. Por último se evaluaron los hábitos de testeo para HIV indagando que factores facilitan o impiden su realización. El estudio constó de dos fases, en primer lugar una fase cualitativa y posteriormente una fase cuantitativa con una duración total de 4 años y medio. Durante la fase cualitativa se realizaron 44 entrevistas individuales en profundidad, 8 grupos focales y 10 observaciones etnográficas (hoteles, baños públicos (“teteras”), cines pornográficos, fiestas privadas, dark rooms y discotecas). Durante la fase cuantitativa del estudio se realizó el reclutamiento de 500 participantes que provinieron de la Ciudad Autónoma de Buenos Aires, así como del Gran Buenos Aires. El reclutamiento se comenzó con 16 participantes llamados semillas. Se realizó el diagnóstico de infección por HIV, hepatitis B y C (HBV y HCV), Treponema pallidum, Virus Papiloma Humano (HPV) y Chlamidias. La colaboración establecida entre los grupos de trabajo enfocados en áreas diversas posibilitó el abordaje conjunto de nuevas estrategias de investigación antes no exploradas en nuestro país. Los resultados más relevantes de esta investigación serán progresivamente publicados en sucesivos números de Actualizaciones en SIDA. PMID:25264397

  1. Cardiovascular diseases in older patients with osteoporotic hip fracture: prevalence, disturbances in mineral and bone metabolism, and bidirectional links

    PubMed Central

    Fisher, A; Srikusalanukul, W; Davis, M; Smith, P

    2013-01-01

    Background Considerable controversy exists regarding the contribution of mineral/bone metabolism abnormalities to the association between cardiovascular diseases (CVDs) and osteoporotic fractures. Aims and methods To determine the relationships between mineral/bone metabolism biomarkers and CVD in 746 older patients with hip fracture, clinical data were recorded and serum concentrations of parathyroid hormone (PTH), 25-hydroxyvitamin D, calcium, phosphate, magnesium, troponin I, parameters of bone turnover, and renal, liver, and thyroid functions were measured. Results CVDs were diagnosed in 472 (63.3%) patients. Vitamin D deficiency was similarly prevalent in patients with (78.0%) and without (82.1%) CVD. The CVD group had significantly higher mean PTH concentrations (7.6 vs 6.0 pmol/L, P < 0.001), a higher prevalence of secondary hyperparathyroidism (SPTH) (PTH > 6.8 pmol/L, 43.0% vs 23.3%, P < 0.001), and excess bone resorption (urinary deoxypyridinoline corrected by creatinine [DPD/Cr] > 7.5 nmol/μmol, 87.9% vs 74.8%, P < 0.001). In multivariate regression analysis, SHPT (odds ratio [OR] 2.6, P = 0.007) and high DPD/Cr (OR 2.8, P = 0.016) were independent indictors of CVD. Compared to those with both PTH and DPD/Cr in the normal range, multivariate-adjusted ORs for the presence of CVD were 17.3 (P = 0.004) in subjects with SHPT and 9.7 (P < 0.001) in patients with high DPD/Cr. CVD was an independent predicator of SHPT (OR 2.8, P = 0.007) and excess DPD/Cr (OR 2.5, P = 0.031). CVD was predictive of postoperative myocardial injury, while SHPT was also an independent predictor of prolonged hospital stay and in-hospital death. Conclusion SHPT and excess bone resorption are independent pathophysiological mediators underlying the bidirectional associations between CVD and hip fracture, and therefore are important diagnostic and therapeutic targets. PMID:23460043

  2. Added Value of 3D Proton-Density Weighted Images in Diagnosis of Intracranial Arterial Dissection

    PubMed Central

    Kim, Jin Woo; Kim, Young Dae; Lee, Seung-Koo; Lim, Soo Mee; Oh, Se Won

    2016-01-01

    Background An early and reliable diagnosis of intracranial arterial dissection is important to reduce the risk of neurological complication. The purpose of this study was to assess the clinical usefulness of three-dimensional high-resolution MRI (3D-HR-MRI) including pre- and post-contrast T1-weighted volumetric isotropic turbo spin echo acquisition with improved motion-sensitized driven equilibrium preparation (3D-iMSDE-T1) and proton-density weighted image (3D-PD) in detecting dissection and to evaluate the added value of 3D-PD in diagnosing intracranial arterial dissection. Methods We retrospectively recruited patients who underwent 3D-HR-MRI with clinical suspicion of arterial dissection. Among them, we selected patients who were diagnosed with definite dissection according to the Spontaneous Cervicocephalic Arterial Dissections Study criteria. For each patient, the presence of intimal flap, intramural hematoma, and vessel dilatation were evaluated independently by two neuroradiologists on each sequence. Interobserver agreement was assessed. Results Seventeen patients (mean age: 41 ± 10 [SD] years; 13 men) were diagnosed with definite dissection. The intimal flaps were more frequently detected on 3D-PD (88.2%, 15/17) than on 3D-iMSDE-T1 (29.4%, 5/17), and post-contrast 3D-iMSDE-T1 (35.3%, 6/17; P = 0.006 and P = 0.004, respectively). No significant difference was found in the detection rate of intramural hematomas (59–71%) and vascular dilatations (47%) on each sequence. Interobserver agreement for detection of dissection findings showed almost perfect agreement (k = 0.84–1.00), except for detection of intimal flaps on pre-contrast 3D-iMSDE-T1 (k = 0.62). After addition of 3D-PD to pre- and post-contrast 3D-iMSDE-T1, more patients were diagnosed with definite dissection with the initial MRI (88.2% vs. 47.1%; P = 0.039). Conclusions The intimal flap might be better visualized on the 3D-PD sequence than the 3D-iMSDE-T1 sequences, allowing diagnosis of

  3. Multi-scale coarse-graining of non-conservative interactions in molecular liquids

    SciTech Connect

    Izvekov, Sergei Rice, Betsy M.

    2014-03-14

    A new bottom-up procedure for constructing non-conservative (dissipative and stochastic) interactions for dissipative particle dynamics (DPD) models is described and applied to perform hierarchical coarse-graining of a polar molecular liquid (nitromethane). The distant-dependent radial and shear frictions in functional-free form are derived consistently with a chosen form for conservative interactions by matching two-body force-velocity and three-body velocity-velocity correlations along the microscopic trajectories of the centroids of Voronoi cells (clusters), which represent the dissipative particles within the DPD description. The Voronoi tessellation is achieved by application of the K-means clustering algorithm at regular time intervals. Consistently with a notion of many-body DPD, the conservative interactions are determined through the multi-scale coarse-graining (MS-CG) method, which naturally implements a pairwise decomposition of the microscopic free energy. A hierarchy of MS-CG/DPD models starting with one molecule per Voronoi cell and up to 64 molecules per cell is derived. The radial contribution to the friction appears to be dominant for all models. As the Voronoi cell sizes increase, the dissipative forces rapidly become confined to the first coordination shell. For Voronoi cells of two and more molecules the time dependence of the velocity autocorrelation function becomes monotonic and well reproduced by the respective MS-CG/DPD models. A comparative analysis of force and velocity correlations in the atomistic and CG ensembles indicates Markovian behavior with as low as two molecules per dissipative particle. The models with one and two molecules per Voronoi cell yield transport properties (diffusion and shear viscosity) that are in good agreement with the atomistic data. The coarser models produce slower dynamics that can be appreciably attributed to unaccounted dissipation introduced by regular Voronoi re-partitioning as well as by larger

  4. Longitudinal Study of Hepatitis A Infection by Saliva Sampling: The Kinetics of HAV Markers in Saliva Revealed the Application of Saliva Tests for Hepatitis A Study.

    PubMed

    Amado Leon, Luciane Almeida; de Almeida, Adilson José; de Paula, Vanessa Salete; Tourinho, Renata Santos; Villela, Daniel Antunes Maciel; Gaspar, Ana Maria Coimbra; Lewis-Ximenez, Lia Laura; Pinto, Marcelo Alves

    2015-01-01

    Despite the increasing numbers of studies investigating hepatitis A diagnostic through saliva, the frequency and the pattern of hepatitis A virus (HAV) markers in this fluid still remains unknown. To address this issue, we carried on a longitudinal study to examine the kinetics of HAV markers in saliva, in comparison with serum samples. The present study followed-up ten patients with acute hepatitis A infection during 180 days post diagnosis (dpd). Total anti-HAV was detected in paired serum and saliva samples until the end of the follow-up, showing a peak titer at 90th. However, total anti-HAV level was higher in serum than in saliva samples. This HAV marker showed a probability of 100% to be detected in both serum and saliva during 180 dpd. The IgM anti-HAV could be detected in saliva up to 150 dpd, showing the highest frequency at 30th, when it was detected in all individuals. During the first month of HAV infection, this acute HAV marker showed a detection probability of 100% in paired samples. The detection of IgM anti-HAV in saliva was not dependent on its level in serum, HAV-RNA detection and/or viral load, since no association was found between IgM anti-HAV positivity in saliva and any of these parameter (p>0.05). Most of the patients (80%) were found to contain HAV-RNA in saliva, mainly at early acute phase (30th day). However, it was possible to demonstrate the HAV RNA presence in paired samples for more than 90 days, even after seroconversion. No significant relationship was observed between salivary HAV-RNA positivity and serum viral load, demonstrating that serum viral load is not predictive of HAV-RNA detection in saliva. Similar viral load was seen in paired samples (on average 104 copies/mL). These data demonstrate that the best diagnostic coverage can be achieved by salivary anti-HAV antibodies and HAV-RNA tests during 30-90 dpd. The long detection and high probability of specific-HAV antibodies positivity in saliva samples make the assessment of

  5. Pharmacokinetics of 5-fluorouracil and increased hepatic dihydropyrimidine dehydrogenase activity levels in 1,2-dimethylhydrazine-induced colorectal cancer model rats.

    PubMed

    Kobuchi, Shinji; Ito, Yukako; Okada, Kae; Imoto, Kazuki; Takada, Kanji

    2013-09-01

    To investigate the hepatic dihydropyrimidine dehydrogenase (DPD) activity in colorectal cancer (CRC), which is critically important to create a patient-specific dosing regimen, we performed 5-FU pharmacokinetic studies in 1,2-dimethylhydrazine-induced CRC model rats (CRC rats). After rats received 5-FU intravenous (IV) bolus injections, the area under the plasma concentration-time curve (AUC) and elimination half-life (t 1/2) in CRC rats (10.02 ± 0.37 μg h mL(-1), 0.30 ± 0.02 h, respectively) were significantly lower than that in control rats (13.46 ± 1.20 μg h mL(-1), 0.52 ± 0.05 h, respectively), whereas total plasma clearance (CLtot) in CRC rats (2.01 ± 0.07 L h(-1) kg(-1)) was significantly increased compared with that in control rats (1.54 ± 0.14 L h(-1) kg(-1)). Conversely, the avoidance ratio of the hepatic first-pass effect was approximately 20 % lower than that in control rats. Of interest is that hepatic DPD activity levels and the dihydrouracil-uracil ratio (UH2/Ura ratio) in plasma, which may act as a potential biomarker to evaluate hepatic DPD activity levels, were significantly increased in CRC rats. These results suggest that the decrease of hepatic availability in CRC rats is brought about by the increase in intrinsic clearance induced by the increase in DPD activity, resulting in a decrease in AUC and t 1/2 and an increase in CLtot after 5-FU IV bolus injection. Along with a proper dosing regimen for patients with CRC, a hepatic DPD activity monitoring system, such as the determination of UH2/Ura ratio in plasma, is desirable.

  6. Longitudinal Study of Hepatitis A Infection by Saliva Sampling: The Kinetics of HAV Markers in Saliva Revealed the Application of Saliva Tests for Hepatitis A Study

    PubMed Central

    Amado Leon, Luciane Almeida; de Almeida, Adilson José; de Paula, Vanessa Salete; Tourinho, Renata Santos; Villela, Daniel Antunes Maciel; Gaspar, Ana Maria Coimbra; Lewis-Ximenez, Lia Laura; Pinto, Marcelo Alves

    2015-01-01

    Despite the increasing numbers of studies investigating hepatitis A diagnostic through saliva, the frequency and the pattern of hepatitis A virus (HAV) markers in this fluid still remains unknown. To address this issue, we carried on a longitudinal study to examine the kinetics of HAV markers in saliva, in comparison with serum samples. The present study followed-up ten patients with acute hepatitis A infection during 180 days post diagnosis (dpd). Total anti-HAV was detected in paired serum and saliva samples until the end of the follow-up, showing a peak titer at 90th. However, total anti-HAV level was higher in serum than in saliva samples. This HAV marker showed a probability of 100% to be detected in both serum and saliva during 180 dpd. The IgM anti-HAV could be detected in saliva up to 150 dpd, showing the highest frequency at 30th, when it was detected in all individuals. During the first month of HAV infection, this acute HAV marker showed a detection probability of 100% in paired samples. The detection of IgM anti-HAV in saliva was not dependent on its level in serum, HAV-RNA detection and/or viral load, since no association was found between IgM anti-HAV positivity in saliva and any of these parameter (p>0.05). Most of the patients (80%) were found to contain HAV-RNA in saliva, mainly at early acute phase (30th day). However, it was possible to demonstrate the HAV RNA presence in paired samples for more than 90 days, even after seroconversion. No significant relationship was observed between salivary HAV-RNA positivity and serum viral load, demonstrating that serum viral load is not predictive of HAV-RNA detection in saliva. Similar viral load was seen in paired samples (on average 104 copies/mL). These data demonstrate that the best diagnostic coverage can be achieved by salivary anti-HAV antibodies and HAV-RNA tests during 30–90 dpd. The long detection and high probability of specific-HAV antibodies positivity in saliva samples make the assessment of

  7. Self-Assembly and Critical Aggregation Concentration Measurements of ABA Triblock Copolymers with Varying B Block Types: Model Development, Prediction, and Validation.

    PubMed

    Aydin, Fikret; Chu, Xiaolei; Uppaladadium, Geetartha; Devore, David; Goyal, Ritu; Murthy, N Sanjeeva; Zhang, Zheng; Kohn, Joachim; Dutt, Meenakshi

    2016-04-21

    The dissipative particle dynamics (DPD) simulation technique is a coarse-grained (CG) molecular dynamics-based approach that can effectively capture the hydrodynamics of complex systems while retaining essential information about the structural properties of the molecular species. An advantageous feature of DPD is that it utilizes soft repulsive interactions between the beads, which are CG representation of groups of atoms or molecules. In this study, we used the DPD simulation technique to study the aggregation characteristics of ABA triblock copolymers in aqueous medium. Pluronic polymers (PEG-PPO-PEG) were modeled as two segments of hydrophilic beads and one segment of hydrophobic beads. Tyrosine-derived PEG5K-b-oligo(desaminotyrosyl tyrosine octyl ester-suberate)-b-PEG5K (PEG5K-oligo(DTO-SA)-PEG5K) block copolymers possess alternate rigid and flexible components along the hydrophobic oligo(DTO-SA) chain, and were modeled as two segments of hydrophilic beads and one segment of hydrophobic, alternate soft and hard beads. The formation, structure, and morphology of the initial aggregation of the polymer molecules in aqueous medium were investigated by following the aggregation dynamics. The dimensions of the aggregates predicted by the computational approach were in good agreement with corresponding results from experiments, for the Pluronic and PEG5K-oligo(DTO-SA)-PEG5K block copolymers. In addition, DPD simulations were utilized to determine the critical aggregation concentration (CAC), which was compared with corresponding results from an experimental approach. For Pluronic polymers F68, F88, F108, and F127, the computational results agreed well with experimental measurements of the CAC measurements. For PEG5K-b-oligo(DTO-SA)-b-PEG5K block polymers, the complexity in polymer structure made it difficult to directly determine their CAC values via the CG scheme. Therefore, we determined CAC values of a series of triblock copolymers with 3-8 DTO-SA units using DPD

  8. [Subjective memory complaints, perceived stress and coping strategies in young adults].

    PubMed

    Molina-Rodriguez, Sergio; Pellicer-Porcar, Olga; Mirete-Fructuoso, Marcos; Martinez-Amoros, Estefanía

    2016-04-16

    Introduccion. Las quejas subjetivas de memoria son cada vez mas frecuentes entre los adultos jovenes. En la actualidad, no existe bibliografia que analice la relacion entre las quejas de memoria, el estres percibido y las estrategias de afrontamiento de forma conjunta en adultos jovenes. Objetivo. Determinar la contribucion del estres percibido y diferentes estrategias de afrontamiento sobre las quejas subjetivas de memoria en adultos jovenes sanos. Sujetos y metodos. La muestra estuvo compuesta por 299 universitarios, el 71,6% mujeres, con una edad media de 22,54 ± 4,73 años. La variable 'quejas de memoria' se midio con el cuestionario de fallos de memoria; la variable 'estres percibido', con la escala de estres percibido, y las variables referidas a estrategias de afrontamiento, con el inventario de estrategias de afrontamiento. Resultados. Las variables que presentan una mayor aportacion a la varianza de las quejas de memoria son, en primer lugar, estres percibido y estrategias de afrontamiento positivas centradas en el problema, y, en segundo lugar, estrategias de afrontamiento negativas centradas en la emocion y en el problema. Las estrategias de afrontamiento positivas centradas en la emocion presentan una aportacion nula. Conclusion. Una vez mas se evidencia la influencia del estres sobre los procesos de memoria. El empleo de estrategias de afrontamiento positivas centradas en el problema, como la reestructuracion cognitiva y la resolucion de problemas, puede resultar beneficioso para atenuar la presencia de quejas de memoria, y es necesario realizar una mayor investigacion al respecto.

  9. Effects of Strategy Instruction in an EFL Reading Comprehension Course: A Case Study (Efectos de la instrucción de estrategias en un curso de comprensión de lectura en inglés como lengua extranjera: un estudio de caso)

    ERIC Educational Resources Information Center

    Lopera Medina, Sergio

    2012-01-01

    Strategy instruction is useful in teaching contexts. This paper examines the effects of strategy instruction in an EFL reading comprehension course carried out with 26 undergraduate students at a Colombian university. As a research method, a case study was implemented. There were three instruments with which to collect data: reading comprehension…

  10. Improving Eleventh Graders' Reading Comprehension through Text Coding and Double Entry Organizer Reading Strategies (Mejoramiento de la comprensión lectora de estudiantes de grado once mediante las estrategias de lectura de codificación de texto y organizador de doble entrada)

    ERIC Educational Resources Information Center

    Mahecha, Rocío; Urrego, Stella; Lozano, Erika

    2011-01-01

    In this article we report on an innovation project developed with a group of eleventh graders at a public school in Bogotá. Its aim was to encourage students to improve reading comprehension of texts in English. It was conducted taking into account students' needs, interests and level of English. To do it, we implemented two reading strategies:…

  11. Cuidado de Ninos con Necesidades Especiales en el Hogar: Manual de Estrategias y Actividades para Proveedores que Cuidan Ninos en Sus Hogares (Children with Special Needs in Family Day Care Homes: A Handbook of Approaches and Activities for Family Day Care Home Providers).

    ERIC Educational Resources Information Center

    de la Brosse, Beatrice

    Practical information and sample teaching activities for child caregivers who work with young developmentally disabled children in family day care settings are provided in this manual. Each chapter shares a typical experience a caregiver may have with a particular child. Chapter 1 focuses on getting to know a new child, initial expectations, and…

  12. Using Case Study Methodology to Approach the Views of Teachers of English on Classroom Disciplinary Strategies (Uso de la metodología de estudio de casos para aproximarse a las concepciones de profesores de inglés sobre las estrategias disciplinarias en el aula)

    ERIC Educational Resources Information Center

    Díaz Larenas, Claudio

    2012-01-01

    This qualitative study aims at identifying the disciplinary strategies claimed to be used by a group of five secondary classroom teachers of English in public or semi-public schools in Chile. To conduct this research, a semi-structured interview was applied to participants. The data were analyzed using the principles of semantic content analysis…

  13. "On Air": Participation in an Online Radio Show to Foster Speaking Confidence. A Cooperative Learning-Based Strategies Study ("Al aire": participación en un programa de radio en línea para fomentar la confianza al hablar. Un estudio basado en estrategias de aprendizaje cooperativo)

    ERIC Educational Resources Information Center

    Lemos Tello, Nubia Consuelo

    2012-01-01

    The daily observation of class sessions has enabled me to recognize that students possess a feeling of self-distrust in oral activities. For this reason, I designed a study carried out with a group of twelve eighth graders. This article illustrates an action research project conducted to enhance students' confidence when speaking on an online…

  14. Exploring Knowledge of English Speaking Strategies in 8th and 12th Graders (Exploración del conocimiento de las estrategias de expresión oral en inglés en estudiantes de los grados octavo y doceavo)

    ERIC Educational Resources Information Center

    Diaz Larenas, Claudio

    2011-01-01

    This article presents a research study that analyses eighth and twelfth graders' knowledge of speaking strategies to communicate in English. The Oral Communication Strategy Inventory, developed by Nakatani in 2006, was applied to 108 students belonging to the public, semi-public and private educational sectors in Chile. The findings show that 8th…

  15. Building ESP Content-Based Materials to Promote Strategic Reading (Diseño de materiales basados en contenidos para fomentar estrategias de lectura en un curso de inglés con propósitos específicos)

    ERIC Educational Resources Information Center

    Bautista Barón, Myriam Judith

    2013-01-01

    This article reports on an action research project that proposes to improve the reading comprehension and vocabulary of undergraduate students of English for Specific Purposes--explosives majors, at a police training institute in Colombia. I used the qualitative research method to explore and reflect upon the teaching-learning processes during…

  16. Quality of life and religious-spiritual coping in palliative cancer care patients.

    PubMed

    Matos, Ticiane Dionizio de Sousa; Meneguin, Silmara; Ferreira, Maria de Lourdes da Silva; Miot, Helio Amante

    2017-07-10

    voluntários saudáveis, por meio de questionário utilizando dados sociodemográficos, o McGill Quality of Life Questionnaire e o Coping Religioso-Espiritual-Breve. foram entrevistados 192 participantes que apresentaram boa qualidade de vida e alta utilização do Coping Religioso-Espiritual. Houve maior uso de Coping Religioso-Espiritual negativo no Grupo A, assim como menor bem-estar físico, psicológico e de qualidade de vida. Observou-se associação entre escores de qualidade de vida e Coping Religioso-Espiritual (p<0,01) em ambos os grupos. Sexo masculino, religião católica e escore de Coping Regioso-Espiritual-Breve influenciaram, de forma independente, os escores de qualidade de vida (p<0,01). ambos os grupos apresentaram escores altos de qualidade de vida e de Coping Espiritual-Religioso. Participantes do sexo masculino, praticantes de religião católica e com maiores escores de Coping Espiritual-Religioso apresentaram melhor percepção de qualidade de vida, sugerindo que essa estratégia de enfrentamento possa ser estimulada em pacientes sob cuidados paliativos. comparar la calidad de vida y el coping religioso-espiritual de pacientes en cuidados paliativos oncológicos con un grupo de participantes sanos; evaluar si la calidad de vida percibida está asociada a las estrategias de coping religioso-espiritual; identificar las variables clínicas y sociodemográficas relacionadas a la calidad de vida y al coping religioso-espiritual. estudio transversal, desarrollado con 96 pacientes de ambulatorio de cuidados paliativos en un hospital público en el interior del Estado de São Paulo, Brasil, y 96 voluntarios sanos, mediante cuestionario utilizando datos sociodemográficos, el McGill Quality of Life Questionnaire y el Coping Religioso-Espiritual-Breve. fueron entrevistados 192 participantes que presentaron buena calidad de vida y alta utilización del Coping Religioso-Espiritual. Fue encontrado mayor uso de Coping Religioso-Espiritual negativo en el Grupo A

  17. Primary care for diabetes mellitus patients from the perspective of the care model for chronic conditions.

    PubMed

    Salci, Maria Aparecida; Meirelles, Betina Hörner Schlindwein; Silva, Denise Maria Guerreiro Vieira da

    2017-03-09

    ATLAS.ti, utilizando la técnica de análisis de contenido dirigida. en el ámbito micro, la atención estaba distante de la integralidad de las acciones necesarias para asistir a las personas con enfermedad crónica y estaba centrada en el modelo biomédico. En el ámbito meso, existía desarticulación entre los profesionales de la Estrategia Salud de la Familia, entre estos y los usuarios, familia y comunidad. En el ámbito macro, se identificó ausencia de estrategias directivas para la implementación de las políticas públicas para la diabetes en la práctica asistencial. la implementación del Modelo de Atención a las Condiciones Crónicas representa un gran reto, necesitando principalmente de profesionales y gestores preparados para trabajar con enfermedades crónicas y abiertos a romper con el modelo tradicional. avaliar a atenção à saúde desenvolvida pelos integrantes da Atenção Primária à Saúde às pessoas com diabetes mellitus na perspectiva do Modelo de Atenção às Condições Crônicas. estudo qualitativo, com referencial teórico do Pensamento Complexo e do Modelo de Atenção às Condições Crônicas e metodológico da pesquisa avaliativa. Para a coleta de dados foram realizadas 38 entrevistas com profissionais de saúde e gestores; observação das atividades realizadas pelas equipes de saúde; e análise de 25 prontuários de pessoas que recebiam esse atendimento. A análise de dados teve auxílio do software ATLAS.ti, utilizando a técnica de análise de conteúdo dirigida. no âmbito micro, a assistência estava distante da integralidade das ações necessárias para assistir às pessoas com doença crônica e estava centrada no modelo biomédico. No âmbito meso, existia desarticulação entre os profissionais da Estratégia Saúde da Família, destes com os usuários, família e comunidade. No âmbito macro, identificou-se ausência de estratégias diretivas para a implementação das políticas públicas para o diabetes na pr

  18. [Comparison of the classification of pulmonary hypertension due to left heart disease according to transpulmonary pressure gradient or diastolic pressure difference methods].

    PubMed

    Zhang, Hao; Zhang, Haifeng; Sun, Wei; Sheng, Yanhui; Yang, Rong; Xu, Dongjie; Zhou, Fang; Xu, Ying; Zhou, Yanli; Kong, Xiangqing; Li, Xinli

    2015-09-01

    To compare the features of patients with pulmonary hypertension due to left heart disease classified according to transpulmonary gradient (TGP) or diastolic pressure difference (DPD). Thirty-three patients with pulmonary hypertension due to left heart disease diagnosed by right heart catheterization were enrolled. Patients were divided into two groups according to TPG: 17 patients with TPG ≤ 12 mmHg (1 mmHg = 0.133 kPa) and 16 patients with TPG > 12 mmHg; or divided into two groups according to DPD: 23 patients with DPD < 7 mmHg and 10 patients with DPD ≥ 7 mmHg. McNemar's method was used to test the agreement of the two classification methods. Below are the patients features according to the classification by TPG: central venous pressure ((9.0 ± 2.5) vs. (12.7 ± 5.4) mmHg), mean right atria pressure ((9.1 ± 2.4) vs. (12.8 ± 5.2) mmHg), right heart systolic pressure ((45.5 ± 9.8) vs. (66.8 ± 15.4) mmHg), right heart mean pressure ((22.6 ± 5.2) vs. (33.1 ± 7.5) mmHg), pulmonary systolic pressure ((44.2 ± 10.3) vs. (64.8 ± 14.2) mmHg), pulmonary diastolic pressure ((24.2 ± 4.5) vs. (33.1 ± 8.3) mmHg), pulmonary mean pressure ((32.3 ± 5.7) vs. (45.8 ± 8.6) mmHg), cardiac index ((2.6 ± 1.0) vs. (1.9 ± 0.9) L · min(-1) · m(-2)), right heart EF ((31.2 ± 12.6)% vs. (22.6 ± 7.1) %) and pulmonary vascular resistance ((2.3 ± 0.8) vs. (6.3 ± 2.6) Wood) were significantly different between the two groups (all P < 0.05). According to the classification of DPD, only right heart diastolic pressure ((7.4 ± 3.7) vs. (11.5 ± 5.7) mmHg), pulmonary diastolic pressure ((25.9 ± 6.4) vs. (34.7 ± 8.0) mmHg) and pulmonary vascular resistance ((3.3 ± 2.0) vs. (6.2 ± 3.4) Wood) were significantly different between the two groups (all P < 0.05). These was a weak agreement (κ = 0.386 6, 95% CI: 0.092 2-0.681 0) between the two classification methods. TPG classification is superior to DPD classification for pulmonary hypertension patients due to left heart

  19. Multiscale Universal Interface: A concurrent framework for coupling heterogeneous solvers

    NASA Astrophysics Data System (ADS)

    Tang, Yu-Hang; Kudo, Shuhei; Bian, Xin; Li, Zhen; Karniadakis, George Em

    2015-09-01

    Concurrently coupled numerical simulations using heterogeneous solvers are powerful tools for modeling multiscale phenomena. However, major modifications to existing codes are often required to enable such simulations, posing significant difficulties in practice. In this paper we present a C++ library, i.e. the Multiscale Universal Interface (MUI), which is capable of facilitating the coupling effort for a wide range of multiscale simulations. The library adopts a header-only form with minimal external dependency and hence can be easily dropped into existing codes. A data sampler concept is introduced, combined with a hybrid dynamic/static typing mechanism, to create an easily customizable framework for solver-independent data interpretation. The library integrates MPI MPMD support and an asynchronous communication protocol to handle inter-solver information exchange irrespective of the solvers' own MPI awareness. Template metaprogramming is heavily employed to simultaneously improve runtime performance and code flexibility. We validated the library by solving three different multiscale problems, which also serve to demonstrate the flexibility of the framework in handling heterogeneous models and solvers. In the first example, a Couette flow was simulated using two concurrently coupled Smoothed Particle Hydrodynamics (SPH) simulations of different spatial resolutions. In the second example, we coupled the deterministic SPH method with the stochastic Dissipative Particle Dynamics (DPD) method to study the effect of surface grafting on the hydrodynamics properties on the surface. In the third example, we consider conjugate heat transfer between a solid domain and a fluid domain by coupling the particle-based energy-conserving DPD (eDPD) method with the Finite Element Method (FEM).

  20. Relationships between myocardial injury, all-cause mortality, vitamin D, PTH, and biochemical bone turnover markers in older patients with hip fractures.

    PubMed

    Fisher, Alexander A; Southcott, Emma K; Srikusalanukul, Wichat; Davis, Michael W; Hickman, Peter E; Potter, Julia M; Smith, Paul N

    2007-01-01

    This study examined the relationships between myocardial injury as indicated by serum cardiac troponin I (cTnI) elevation, 25 hydroxyvitamin D [25(OH)D], and PTH status and biochemical markers of bone metabolism in older patients with hip fracture (HF). In 238 consecutive patients (mean age 81.9 +/- 7.8 yr; 72% women) with low trauma HF, serum concentrations of cTnI, 25(OH)D, PTH, calcium, phosphorus, magnesium, osteocalcin, bone-specific alkaline phosphatase (BAP), and urine excretion of free deoxypyridinoline (DPD) and N-terminal cross-linked teleopeptide of type I collagen (NTx) were measured and clinical data were collected prospectively. Myocardial injury (cTnI >0.06 microg/L) presented in 29%, 25(OH)D deficiency (<50 nmol/L) in 81.6%, elevated PTH (>6.5 pmol/L) in 53%, and excessive bone resorption (increased DPD and/or NTx excretion) in 93.7%. Multivariate logistic regression showed that elevated serum PTH level is a major predictor of peri-operative myocardial injury (OR = 2.13; 95% CI 1.01-4.51; p = 0.049) and in-hospital all-cause mortality (OR = 18.5; 95% CI 2.0-72.3; p = 0.010), independent of age, sex, 25(OH)D status, and comorbidities. The degree of hyperparathyroidism was associated with the risk of cTnI elevation and the mortality rate. In cTnI positive patients, PTH levels correlated with cTnI concentrations (r = 0.28; p = 0.026) and urine DPD exretion (r = 0.37; p = 0.004). These results suggest for the first time that in older patients with HF, elevated PTH level is associated with peri-operative myocardial injury and in-hospital all-cause mortality, and that elevated PTH level contributes to both disturbed bone metabolism and poor outcomes.

  1. Molecular patterns in deficient mismatch repair colorectal tumours: results from a French prospective multicentric biological and genetic study

    PubMed Central

    Etienne-Grimaldi, M-C; Mahamat, A; Chazal, M; Laurent-Puig, P; Olschwang, S; Gaub, M-P; Formento, J-L; Formento, P; Sudaka, A; Boige, V; Abderrahim-Ferkoune, A; Benchimol, D; André, T; Houry, S; Faucheron, J-L; Letoublon, C; Gilly, F-N; Delpero, J-R; Lasser, P; Pradere, B; Pezet, D; Penault-Llorca, F; Milano, G

    2014-01-01

    Background: To test the prognostic value of tumour protein and genetic markers in colorectal cancer (CRC) and examine whether deficient mismatch repair (dMMR) tumours had a distinct profile relative to proficient mismatch repair (pMMR) tumours. Methods: This prospective multicentric study involved 251 stage I–III CRC patients. Analysed biomarkers were EGFR (binding assay), VEGFA, thymidylate synthase (TS), thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) expressions, MMR status, mutations of KRAS (codons 12–13), BRAF (V600E), PIK3CA (exons 9 and 20), APC (exon 15) and P53 (exons 4–9), CpG island methylation phenotype status, ploidy, S-phase, LOH. Results: The only significant predictor of relapse-free survival (RFS) was tumour staging. Analyses restricted to stage III showed a trend towards a shorter RFS in KRAS-mutated (P=0.005), BRAF wt (P=0.009) and pMMR tumours (P=0.036). Deficient mismatch repair tumours significantly demonstrated higher TS (median 3.1 vs 1.4) and TP (median 5.8 vs 3.5) expression relative to pMMR (P<0.001) and show higher DPD expression (median 14.9 vs 7.9, P=0.027) and EGFR content (median 69 vs 38, P=0.037) relative to pMMR. Conclusions: Present data suggesting that both TS and DPD are overexpressed in dMMR tumours as compared with pMMR tumours provide a strong rationale that may explain the resistance of dMMR tumours to 5FU-based therapy. PMID:24800948

  2. Increased urinary indoxyl sulfate (indican): new insights into gut dysbiosis in Parkinson's disease.

    PubMed

    Cassani, Erica; Barichella, Michela; Cancello, Raffaella; Cavanna, Ferruccio; Iorio, Laura; Cereda, Emanuele; Bolliri, Carlotta; Zampella Maria, Paola; Bianchi, Francesca; Cestaro, Benvenuto; Pezzoli, Gianni

    2015-04-01

    Changes in the composition of gut microflora have been associated with an increase in chronic diseases. Indican urinary concentration is one of the most common and easily assessable markers of intestinal dysbiosis. Little information is available on intestinal dysbiosis in Parkinson's disease (PD). We decided to investigate indican urinary concentrations in a cohort of PD patients. A case-control study including PD patients (N = 68) on treatment with levodopa (PD) or on no pharmacological treatment (De Novo, DPD; N=34) and an age and gender-matched healthy control group (CTR; N=50). Main confounders, such as nutritional habits and constipation diagnosed according to Rome III criteria, were also investigated. Indican urinary concentrations were significantly higher in PD and DPD than in CTR (P < 0.001 and P < 0.01, respectively). In PD patients the concentrations were unrelated to the presence of constipation, whereas this symptom was associated with higher concentrations in controls (P=0.043). The frequency of dairy product consumption was also positively associated with increased concentrations (P=0.008). Predictors of indican concentrations were sought by multivariate linear regression analysis. The higher indican urinary concentrations found in both DPD (P=0.045) and PD (P=0.023) patients persisted after adjustment for age, gender, BMI, constipation and consumption of dairy products. Gut dysbiosis seems to be an important issue in PD, independently of the presence of constipation and starting from the early stages of the disease. The role of gut dysbiosis in the pathogenesis of PD deserves further investigation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Changes in skeletal collagen crosslinks and matrix hydration in high and low turnover chronic kidney disease

    PubMed Central

    Allen, Matthew R.; Newman, Christopher L.; Chen, Neal; Granke, Mathilde; Nyman, Jeffry S.; Moe, Sharon M.

    2015-01-01

    Purpose/Introduction Clinical data have documented a clear increase in fracture risk associated with chronic kidney disease (CKD). Preclinical studies have shown reductions in bone mechanical properties although the tissue-level mechanisms for these differences remain unclear. The goal of this study was to assess collagen cross-links and matrix hydration, two variables known to affect mechanical properties, in animals with either high or low turnover CKD. Methods At 35 weeks of age (>75% reduction in kidney function), the femoral diaphysis of male Cy/+ rats with high or low bone turnover rates, along with normal littermate (NL) controls, were assessed for collagen cross-links (pyridinoline (PYD), deoxypyridinoline (DPD), and pentosidine (PE)) using a high performance liquid chromatography (HPLC) assay as well as pore and bound water per volume (pw and bw) using a 1H nuclear magnetic resonance (NMR) technique. Material-level biomechanical properties were calculated based on previously published whole bone mechanical tests. Results Cortical bone from animals with high turnover disease had lower Pyd and Dpd crosslink levels (−21% each), lower bw (−10%), higher PE (+71%), and higher pw (+46%), compared to NL. Animals with low turnover had higher Dpd, PE (+71%), and bw (+7%) along with lower pw (−60%) compared to NL. Both high and low turnover animals had reduced material-level bone toughness compared to NL animals as determined by three-point bending. Conclusions These data document an increase in skeletal PE with advanced CKD that is independent of bone turnover rate and inversely related to decline in kidney function. Although hydration changes occur in both high and low turnover disease, the data suggest that non-enzymatic collagen crosslinks may be a key factor in compromised mechanical properties of CKD. PMID:25466530

  4. Multiscale Universal Interface: A concurrent framework for coupling heterogeneous solvers

    SciTech Connect

    Tang, Yu-Hang; Kudo, Shuhei; Bian, Xin; Li, Zhen; Karniadakis, George Em

    2015-09-15

    Graphical abstract: - Abstract: Concurrently coupled numerical simulations using heterogeneous solvers are powerful tools for modeling multiscale phenomena. However, major modifications to existing codes are often required to enable such simulations, posing significant difficulties in practice. In this paper we present a C++ library, i.e. the Multiscale Universal Interface (MUI), which is capable of facilitating the coupling effort for a wide range of multiscale simulations. The library adopts a header-only form with minimal external dependency and hence can be easily dropped into existing codes. A data sampler concept is introduced, combined with a hybrid dynamic/static typing mechanism, to create an easily customizable framework for solver-independent data interpretation. The library integrates MPI MPMD support and an asynchronous communication protocol to handle inter-solver information exchange irrespective of the solvers' own MPI awareness. Template metaprogramming is heavily employed to simultaneously improve runtime performance and code flexibility. We validated the library by solving three different multiscale problems, which also serve to demonstrate the flexibility of the framework in handling heterogeneous models and solvers. In the first example, a Couette flow was simulated using two concurrently coupled Smoothed Particle Hydrodynamics (SPH) simulations of different spatial resolutions. In the second example, we coupled the deterministic SPH method with the stochastic Dissipative Particle Dynamics (DPD) method to study the effect of surface grafting on the hydrodynamics properties on the surface. In the third example, we consider conjugate heat transfer between a solid domain and a fluid domain by coupling the particle-based energy-conserving DPD (eDPD) method with the Finite Element Method (FEM)

  5. Helicobacter pylori perceives the quorum-sensing molecule AI-2 as a chemorepellent via the chemoreceptor TlpB

    PubMed Central

    Rader, Bethany A.; Wreden, Christopher; Hicks, Kevin G.; Sweeney, Emily Goers; Ottemann, Karen M.

    2011-01-01

    Helicobacter pylori moves in response to environmental chemical cues using a chemotaxis two-component signal-transduction system. Autoinducer-2 (AI-2) is a quorum-sensing signal produced by the LuxS protein that accumulates in the bacterial environment in a density-dependent manner. We showed previously that a H. pylori luxS mutant was defective in motility on soft agar plates. Here we report that deletion of the luxS gene resulted in swimming behaviour with a reduced frequency of stops as compared to the wild-type strain. Stopping frequency was restored to wild-type levels by genetic complementation of the luxS mutation or by addition of synthetic 4,5-dihydroxy-2,3-pentanedione (DPD), which cyclizes to form AI-2. Synthetic DPD also increased the frequency of stops in wild-type H. pylori, similar to the behaviour induced by the known chemorepellent HCl. We found that whereas mutants lacking the chemoreceptor genes tlpA, tlpC or tlpD responded to an exogenous source of synthetic DPD, the chemoreceptor mutant tlpB was non-responsive to a gradient or uniform distribution of the chemical. Furthermore, a double mutant lacking both tlpB and luxS exhibited chemotactic behaviour similar to the tlpB single mutant, whereas a double mutant lacking both tlpB and the chemotransduction gene cheA behaved like a nonchemotactic cheA single mutant, supporting the model that tlpB functions in a signalling pathway downstream of luxS and upstream of cheA. We conclude that H. pylori perceives LuxS-produced AI-2 as a chemorepellent via the chemoreceptor TlpB. PMID:21602215

  6. Amino acid supplementation alters bone metabolism during simulated weightlessness

    NASA Technical Reports Server (NTRS)

    Zwart, S. R.; Davis-Street, J. E.; Paddon-Jones, D.; Ferrando, A. A.; Wolfe, R. R.; Smith, S. M.

    2005-01-01

    High-protein and acidogenic diets induce hypercalciuria. Foods or supplements with excess sulfur-containing amino acids increase endogenous sulfuric acid production and therefore have the potential to increase calcium excretion and alter bone metabolism. In this study, effects of an amino acid/carbohydrate supplement on bone resorption were examined during bed rest. Thirteen subjects were divided at random into two groups: a control group (Con, n = 6) and an amino acid-supplemented group (AA, n = 7) who consumed an extra 49.5 g essential amino acids and 90 g carbohydrate per day for 28 days. Urine was collected for n-telopeptide (NTX), deoxypyridinoline (DPD), calcium, and pH determinations. Bone mineral content was determined and potential renal acid load was calculated. Bone-specific alkaline phosphatase was measured in serum samples collected on day 1 (immediately before bed rest) and on day 28. Potential renal acid load was higher in the AA group than in the Con group during bed rest (P < 0.05). For all subjects, during bed rest urinary NTX and DPD concentrations were greater than pre-bed rest levels (P < 0.05). Urinary NTX and DPD tended to be higher in the AA group (P = 0.073 and P = 0.056, respectively). During bed rest, urinary calcium was greater than baseline levels (P < 0.05) in the AA group but not the Con group. Total bone mineral content was lower after bed rest than before bed rest in the AA group but not the Con group (P < 0.05). During bed rest, urinary pH decreased (P < 0.05), and it was lower in the AA group than the Con group. These data suggest that bone resorption increased, without changes in bone formation, in the AA group.

  7. Targeting miR-21 enhances the sensitivity of human colon cancer HT-29 cells to chemoradiotherapy in vitro

    SciTech Connect

    Deng, Jun; Lei, Wan; Fu, Jian-Chun; Zhang, Ling; Li, Jun-He; Xiong, Jian-Ping

    2014-01-17

    Highlight: •MiR-21 plays a significant role in 5-FU resistance. •This role might be attributed to targeting of hMSH2 as well as TP and DPD via miR-21 targeted hMSH2. •Indirectly targeted TP and DPD to influence 5-FU chemotherapy sensitivity. -- Abstract: 5-Fluorouracil (5-FU) is a classic chemotherapeutic drug that has been widely used for colorectal cancer treatment, but colorectal cancer cells are often resistant to primary or acquired 5-FU therapy. Several studies have shown that miR-21 is significantly elevated in colorectal cancer. This suggests that this miRNA might play a role in this resistance. In this study, we investigated this possibility and the possible mechanism underlying this role. We showed that forced expression of miR-21 significantly inhibited apoptosis, enhanced cell proliferation, invasion, and colony formation ability, promoted G1/S cell cycle transition and increased the resistance of tumor cells to 5-FU and X radiation in HT-29 colon cancer cells. Furthermore, knockdown of miR-21 reversed these effects on HT-29 cells and increased the sensitivity of HT-29/5-FU to 5-FU chemotherapy. Finally, we showed that miR-21 targeted the human mutS homolog2 (hMSH2), and indirectly regulated the expression of thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD). These results demonstrate that miR-21 may play an important role in the 5-FU resistance of colon cancer cells.

  8. Smoothed dissipative particle dynamics with angular momentum conservation

    SciTech Connect

    Müller, Kathrin Fedosov, Dmitry A. Gompper, Gerhard

    2015-01-15

    Smoothed dissipative particle dynamics (SDPD) combines two popular mesoscopic techniques, the smoothed particle hydrodynamics and dissipative particle dynamics (DPD) methods, and can be considered as an improved dissipative particle dynamics approach. Despite several advantages of the SDPD method over the conventional DPD model, the original formulation of SDPD by Español and Revenga (2003) [9], lacks angular momentum conservation, leading to unphysical results for problems where the conservation of angular momentum is essential. To overcome this limitation, we extend the SDPD method by introducing a particle spin variable such that local and global angular momentum conservation is restored. The new SDPD formulation (SDPD+a) is directly derived from the Navier–Stokes equation for fluids with spin, while thermal fluctuations are incorporated similarly to the DPD method. We test the new SDPD method and demonstrate that it properly reproduces fluid transport coefficients. Also, SDPD with angular momentum conservation is validated using two problems: (i) the Taylor–Couette flow with two immiscible fluids and (ii) a tank-treading vesicle in shear flow with a viscosity contrast between inner and outer fluids. For both problems, the new SDPD method leads to simulation predictions in agreement with the corresponding analytical theories, while the original SDPD method fails to capture properly physical characteristics of the systems due to violation of angular momentum conservation. In conclusion, the extended SDPD method with angular momentum conservation provides a new approach to tackle fluid problems such as multiphase flows and vesicle/cell suspensions, where the conservation of angular momentum is essential.

  9. Smoothed dissipative particle dynamics with angular momentum conservation

    NASA Astrophysics Data System (ADS)

    Müller, Kathrin; Fedosov, Dmitry A.; Gompper, Gerhard

    2015-01-01

    Smoothed dissipative particle dynamics (SDPD) combines two popular mesoscopic techniques, the smoothed particle hydrodynamics and dissipative particle dynamics (DPD) methods, and can be considered as an improved dissipative particle dynamics approach. Despite several advantages of the SDPD method over the conventional DPD model, the original formulation of SDPD by Español and Revenga (2003) [9], lacks angular momentum conservation, leading to unphysical results for problems where the conservation of angular momentum is essential. To overcome this limitation, we extend the SDPD method by introducing a particle spin variable such that local and global angular momentum conservation is restored. The new SDPD formulation (SDPD+a) is directly derived from the Navier-Stokes equation for fluids with spin, while thermal fluctuations are incorporated similarly to the DPD method. We test the new SDPD method and demonstrate that it properly reproduces fluid transport coefficients. Also, SDPD with angular momentum conservation is validated using two problems: (i) the Taylor-Couette flow with two immiscible fluids and (ii) a tank-treading vesicle in shear flow with a viscosity contrast between inner and outer fluids. For both problems, the new SDPD method leads to simulation predictions in agreement with the corresponding analytical theories, while the original SDPD method fails to capture properly physical characteristics of the systems due to violation of angular momentum conservation. In conclusion, the extended SDPD method with angular momentum conservation provides a new approach to tackle fluid problems such as multiphase flows and vesicle/cell suspensions, where the conservation of angular momentum is essential.

  10. Blood Flow: Multi-scale Modeling and Visualization

    SciTech Connect

    2010-01-01

    Multi-scale modeling of arterial blood flow can shed light on the interaction between events happening at micro- and meso-scales (i.e., adhesion of red blood cells to the arterial wall, clot formation) and at macro-scales (i.e., change in flow patterns due to the clot). Coupled numerical simulations of such multi-scale flow require state-of-the-art computers and algorithms. Along with developing methods for multi-scale computations, techniques for multi-scale visualizations must be designed. This animation presents early results of joint efforts of teams from Brown University and Argonne National Laboratory to develop a multi-scale visualization methodology. It illustrates a flow of healthy (red) and diseased (blue) blood cells with a Dissipative Particle Dynamics (DPD) method. Each blood cell is represented by a mesh made of 500 DPD-particles, and small spheres show a sub-set of the DPD particles representing the blood plasma, while instantaneous streamlines and slices represent the ensemble average velocity. Credits: Science: Leopold Grinberg and George Karniadakis, Brown University Visualization: Joseph A. Insley and Michael E. Papka, Argonne National Laboratory This research used resources of the Argonne Leadership Computing Facility at Argonne National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under contract DE-AC02-06CH11357. This research was supported in part by the National Science Foundation through the PetaApps program and used TeraGrid resources provided by National Institute for Computational Sciences.

  11. Orotate phosphoribosyltransferase is overexpressed in malignant pleural mesothelioma: Dramatically responds one case in high OPRT expression

    PubMed Central

    Hamamoto, Yoichiro; Takeoka, Shinjiro; Mouri, Atsuto; Fukusumi, Munehisa; Wakuda, Kazushige; Ibe, Tatsuya; Honma, Chie; Arimoto, Yoshihito; Yamada, Kazuaki; Wagatsuma, Miyuki; Tashiro, Akito; Kamoshida, Shingo; Kamimura, Mitsuhiro

    2016-01-01

    ABSTRACT Objective: Malignant pleural mesothelioma (MPM) is a rare and aggressive, treatment-resistant cancer. Pemetrexed, an inhibitor of thymidylate synthase (TS), is used worldwide for MPM as a first-line chemotherapy regimen. However, there is little consensus for a second-line chemotherapy. S-1, a highly effective dihydropyrimidine dehydrogenase (DPD)-inhibitory fluoropyrimidine, mainly acts via a TS inhibitory mechanism similar to pemetrexed. Orotate phosphoribosyltransferase (OPRT) is a key enzyme related to the first step activation of 5-fluorouracil (5-FU) for inhibiting RNA synthesis. We investigated 5-FU related-metabolism proteins, especially focusing on OPRT expression, in MPM Methods and Patients: Fifteen MPM patients who were diagnosed between July 2004 and December 2013 were enrolled. We examined the protein levels of 5-FU metabolism-related enzymes (TS, DPD, OPRT, and thymidine phosphorylase [TP]) in 14 cases Results: High TS, DPD, OPRT, and TP expressions were seen in 28.6%, 71.4%, 85.7%, and 35.7% of patients, respectively. We found that OPRT expression was extremely high in MPM tissue. We experienced one remarkable case of highly effective S-1 combined therapy for pemetrexed refractory MPM. This case also showed high OPRT protein expression Conclusion: The present study suggests that OPRT expression is high in MPM tumors. Although pemetrexed is mainly used for MPM chemotherapy as a TS inhibitor, S-1 has potential as an anticancer drug not only as a TS inhibitor but also inhibiting RNA synthesis through the OPRT pathway. This is the first report investigating OPRT protein expressions in MPM. PMID:27274438

  12. Amino acid supplementation alters bone metabolism during simulated weightlessness

    NASA Technical Reports Server (NTRS)

    Zwart, S. R.; Davis-Street, J. E.; Paddon-Jones, D.; Ferrando, A. A.; Wolfe, R. R.; Smith, S. M.

    2005-01-01

    High-protein and acidogenic diets induce hypercalciuria. Foods or supplements with excess sulfur-containing amino acids increase endogenous sulfuric acid production and therefore have the potential to increase calcium excretion and alter bone metabolism. In this study, effects of an amino acid/carbohydrate supplement on bone resorption were examined during bed rest. Thirteen subjects were divided at random into two groups: a control group (Con, n = 6) and an amino acid-supplemented group (AA, n = 7) who consumed an extra 49.5 g essential amino acids and 90 g carbohydrate per day for 28 days. Urine was collected for n-telopeptide (NTX), deoxypyridinoline (DPD), calcium, and pH determinations. Bone mineral content was determined and potential renal acid load was calculated. Bone-specific alkaline phosphatase was measured in serum samples collected on day 1 (immediately before bed rest) and on day 28. Potential renal acid load was higher in the AA group than in the Con group during bed rest (P < 0.05). For all subjects, during bed rest urinary NTX and DPD concentrations were greater than pre-bed rest levels (P < 0.05). Urinary NTX and DPD tended to be higher in the AA group (P = 0.073 and P = 0.056, respectively). During bed rest, urinary calcium was greater than baseline levels (P < 0.05) in the AA group but not the Con group. Total bone mineral content was lower after bed rest than before bed rest in the AA group but not the Con group (P < 0.05). During bed rest, urinary pH decreased (P < 0.05), and it was lower in the AA group than the Con group. These data suggest that bone resorption increased, without changes in bone formation, in the AA group.

  13. Comparison of site-specific gene expression levels in primary tumors and synchronous lymph node metastases in advanced gastric cancer.

    PubMed

    Naruke, Akira; Azuma, Mizutomo; Takeuchi, Atsuko; Ishido, Kenji; Katada, Chikatoshi; Sasaki, Tohru; Higuchi, Katsuhiko; Tanabe, Satoshi; Saegusa, Makoto; Koizumi, Wasaburo

    2015-04-01

    Many malignant tumors consist of heterogeneous subpopulations of cells. This heterogeneity is associated with genetic characteristics. However, it remains unclear whether gene expression levels differ among specific sites of tumors in gastric cancer. We studied differences in gene expression levels among specific sites of primary tumors and synchronous lymph node metastases, using formalin-fixed, paraffin-embedded specimens resected surgically from 48 patients with previously untreated advanced gastric cancer. Specimens were obtained by laser-captured microdissection from five regions: (1) nonneoplastic mucosa, (2) surface layer (mucosa) of the primary tumor (surface sections), (3) middle layer (submucosa) of the primary tumor (middle sections), (4) the deepest layer of the primary tumor (muscularis propria or deeper) at the site of deepest invasion (deep sections), and (5) level 1 synchronous lymph node metastasis (lymph node metastases). Expression levels of the following target genes were determined by quantitative real-time polymerase chain reaction: thymidylate synthase (TS), thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD), epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), and hypoxia-inducible factor-1α (HIF1α). TP, DPD, EGFR, and HIF1α gene expression levels were significantly higher in deep sections than in surface sections. TP, EGFR, VEGF, and HIF1α gene expression levels were significantly higher in lymph node metastases than in surface sections. TP, DPD, EGFR, VEGF, and HIF1α gene expression levels were positively correlated with the specific samples harvested from the tumors. Our results show that the expression levels of some genes in tumor cells can change in specific sites of tumors and can become higher in association with tumor progression.

  14. Variability of collagen crosslinks: impact of sample collection period.

    PubMed

    Smith, S M; Dillon, E L; DeKerlegand, D E; Davis-Street, J E

    2004-04-01

    Because of the variability of collagen crosslinks, their use as markers for bone resorption is often criticized. We hypothesized that the variability could be reduced by collecting urine for 24 hours (or longer) instead of using single voids, and by not normalizing to creatinine. Urine samples were collected from 22 healthy subjects during two or more 24-hour periods. Each 24-hour pool and each 2nd void of the day were analyzed for N-telopeptide (NTX), pyridinium (PYD), and deoxypyridinoline (DPD) crosslinks. Data were analyzed by using linear regression. For NTX, R2 for the two, 2nd-void samples (n = 38) was 0.55, whereas R2 for the two 24-hour pools was 0.51 or 0.52, expressed per day or per creatinine. For PYD and DPD, R2 for the 2nd-void samples was 0.26 and 0.18, R2 for the 24-hour pools expressed per day was 0.58 and 0.74, and R2 for the 24-hour pools expressed per creatinine was 0.65 and 0.76, respectively. Regression of the 2nd void and the corresponding 24-hour pool, expressed per day, yielded R2 = 0.19, 0.19, and 0.08, for NTX, PYD, and DPD, respectively (n = 76 each). For the 2nd-void sample and its corresponding 24-hour pool, expressed per creatinine, R2 = 0.24, 0.33, and 0.08, respectively. In a separate study, the coefficient of variation for NTX was reduced (P < 0.05) when data from more than one 24-hour collection were combined. Thus, the variability inherent in crosslink determinations can be reduced by collecting urine for longer periods. In research studies, the high variability of single-void collections, compounded by creatinine normalization, may alter or obscure findings.

  15. Possible role of thymidine phosphorylase in gynecological tumors as an individualized treatment strategy

    PubMed Central

    Shida, Masako; Yasuda, Masanori; Fujita, Mariko; Miyazawa, Masaki; Kajiwara, Hiroshi; Hirasawa, Takeshi; Ikeda, Masae; Matsui, Naruaki; Muramatsu, Toshinari; Mikami, Mikio

    2016-01-01

    Thymidine phosphorylase (TP) is structurally similar to platelet-derived endothelial cell growth factor, and it activates 5-fluorouracil (5-FU) prodrugs and also promotes angiogenesis. In the present study, the possibility of using TP expression as a biomarker for 5-FU prodrugs, and the significance of TP as an angiogenic factor, were investigated in patients with gynecological tumors. The subjects enrolled in the study were 188 patients with gynecological tumors who provided informed consent and underwent tumor resection at the Department of Obstetrics and Gynecology of Tokai University Hospital between February 2002 and January 2010. Measurement of the enzymatic activity of TP and dihydropyrimidine dehydrogenase (DPD) was performed by enzyme-linked immunosorbent assay. In addition, immunohistochemistry (IHC) analysis of microvessels by monochrome imaging, western blotting and reverse transcription-polymerase chain reaction were performed. The mean TP activity and the TP/DPD ratio were increased in squamous cell carcinoma of the cervix (306.9 and 2.2 U/mg protein, respectively) and adenosquamous carcinoma (317.6 and 1.4 U/mg protein, respectively) compared with benign tumors and other malignancies, including endometrial (uterine) carcinoma, ovarian serous adenocarcinoma and ovarian mucinous adenocarcinoma. However, these parameters were also elevated in other histological types of cancer such as clear cell adenocarcinoma of the ovary (115.2 and 2.1 U/mg protein, respectively), in which the microvessel area was the largest of all the histological types analyzed. Since high TP expression and a high TP/DPD ratio were identified in other tumors besides cervical cancer, it is possible that patients for whom 5-FU prodrugs are indicated could be selected appropriately if their TP activity is determined and their TP expression is analyzed by IHC prior to initiation of the treatment. PMID:27899985

  16. Analysis of hydrodynamic fluctuations in heterogeneous adjacent multidomains in shear flow

    NASA Astrophysics Data System (ADS)

    Bian, Xin; Deng, Mingge; Tang, Yu-Hang; Karniadakis, George Em

    2016-03-01

    We analyze hydrodynamic fluctuations of a hybrid simulation under shear flow. The hybrid simulation is based on the Navier-Stokes (NS) equations on one domain and dissipative particle dynamics (DPD) on the other. The two domains overlap, and there is an artificial boundary for each one within the overlapping region. To impose the artificial boundary of the NS solver, a simple spatial-temporal averaging is performed on the DPD simulation. In the artificial boundary of the particle simulation, four popular strategies of constraint dynamics are implemented, namely the Maxwell buffer [Hadjiconstantinou and Patera, Int. J. Mod. Phys. C 08, 967 (1997), 10.1142/S0129183197000837], the relaxation dynamics [O'Connell and Thompson, Phys. Rev. E 52, R5792 (1995), 10.1103/PhysRevE.52.R5792], the least constraint dynamics [Nie et al., J. Fluid Mech. 500, 55 (2004), 10.1017/S0022112003007225; Werder et al., J. Comput. Phys. 205, 373 (2005), 10.1016/j.jcp.2004.11.019], and the flux imposition [Flekkøy et al., Europhys. Lett. 52, 271 (2000), 10.1209/epl/i2000-00434-8], to achieve a target mean value given by the NS solver. Going beyond the mean flow field of the hybrid simulations, we investigate the hydrodynamic fluctuations in the DPD domain. Toward that end, we calculate the transversal autocorrelation functions of the fluctuating variables in k space to evaluate the generation, transport, and dissipation of fluctuations in the presence of a hybrid interface. We quantify the unavoidable errors in the fluctuations, due to both the truncation of the domain and the constraint dynamics performed in the artificial boundary. Furthermore, we compare the four methods of constraint dynamics and demonstrate how to reduce the errors in fluctuations. The analysis and findings of this work are directly applicable to other hybrid simulations of fluid flow with thermal fluctuations.

  17. Modelling thrombosis using dissipative particle dynamics method

    PubMed Central

    Filipovic, N; Kojic, M; Tsuda, A

    2008-01-01

    Aim. Arterial occlusion is a leading cause of cardiovascular disease. The main mechanism causing vessel occlusion is thrombus formation, which may be initiated by the activation of platelets. The focus of this study is on the mechanical aspects of platelet-mediated thrombosis which includes the motion, collision, adhesion and aggregation of activated platelets in the blood. A review of the existing continuum-based models is given. A mechanical model of platelet accumulation onto the vessel wall is developed using the dissipative particle dynamics (DPD) method in which the blood (i.e. colloidal-composed medium) is treated as a group of mesoscale particles interacting through conservative, dissipative, attractive and random forces. Methods. Colloidal fluid components (plasma and platelets) are discretized by mesoscopic (micrometre-size) particles that move according to Newton's law. The size of each mesoscopic particle is small enough to allow tracking of each constituent of the colloidal fluid, but significantly larger than the size of atoms such that, in contrast to the molecular dynamics approach, detailed atomic level analysis is not required. Results. To test this model, we simulated the deposition of platelets onto the wall of an expanded tube and compared our computed results with the experimental data of Karino et al. (Miscrovasc. Res. 17, 238–269, 1977). By matching our simulations to the experimental results, the platelet aggregation/adhesion binding force (characterized by an effective spring constant) was determined and found to be within a physiologically reasonable range. Conclusion. Our results suggest that the DPD method offers a promising new approach to the modelling of platelet-mediated thrombosis. The DPD model includes interaction forces between platelets both when they are in the resting state (non-activated) and when they are activated, and therefore it can be extended to the analysis of kinetics of binding and other phenomena relevant to

  18. Changes in markers of bone formation and resorption in a bed rest model of weightlessness

    NASA Technical Reports Server (NTRS)

    Lueken, S. A.; Arnaud, S. B.; Taylor, A. K.; Baylink, D. J.

    1993-01-01

    To study the mechanism of bone loss in physical unloading, we examined indices of bone formation and bone resorption in the serum and urine of eight healthy men during a 7 day -6 degrees head-down tilt bed rest. Prompt increases in markers of resorption--pyridinoline (PD), deoxypyridinoline (DPD), and hydroxyproline (Hyp)/g creatinine--during the first few days of inactivity were paralleled by tartrate-resistant acid phosphatase (TRAP) with significant increases in all these markers by day 4 of bed rest. An index of formation, skeletal alkaline phosphatase (SALP), did not change during bed rest and showed a moderate 15% increase 1 week after reambulation. In contrast to SALP, serum osteocalcin (OC) began increasing the day preceding the increase in Hyp, remained elevated for the duration of the bed rest, and returned to pre-bed rest values within 5 days of reambulation. Similarly, DPD increased significantly at the onset of bed rest, remained elevated for the duration of bed rest, and returned to pre-bed rest levels upon reambulation. On the other hand, the other three indices of resorption, Hyp, PD, and TRAP, remained elevated for 2 weeks after reambulation. The most sensitive indices of the levels of physical activity proved to be the noncollagenous protein, OC, and the collagen crosslinker, DPD. The bed rest values of both these markers were significantly elevated compared to both the pre-bed rest values and the post-bed rest values. The sequence of changes in the circulating markers of bone metabolism indicated that increases in serum OC are the earliest responses of bone to head-down tilt bed rest.

  19. The course of selected bone resorption marker concentrations in response to short-term hypocalcemia experimentally induced with disodium EDTA infusions in dairy cows.

    PubMed

    Liesegang, A; Eicher, R; Sassi, M L; Risteli, J; Riond, J L; Wanner, M

    2000-10-01

    The collagen metabolites hydroxyproline (HYP), deoxypyridinoline (DPD), and the carboxyterminal telopeptide of type I collagen (ICTP) are suitable markers for bone resorption in humans and several animal species. The purpose of this study was to describe the course of bone resorption markers during short-term hypocalcemia induced with disodium ethylenediaminetetraacetic acid (Na2EDTA) and to investigate whether bone resorption is increased in dairy cows under these conditions. EDTA infusions have been used as a model for periparturient paresis in dairy cows and to estimate the calcium mobilization rate from body reserves in ruminants. In this study, hypocalcemia was induced by means of a 5% Na2EDTA infusion (0.55 mg/kg/min Na2EDTA for 5 h = total dose of 100.6 g). Two experiments were conducted: (1) Six 4-11 years-old Brown Swiss cows were infused intravenously with EDTA for 5 h. Blood and urine samples were taken repeatedly from 1 day before until 10 days after infusion. (2) Towards the end of the lactation, the experiment was repeated with the same animals after a 14-day-period of feeding a low calcium diet (26 g/animal per day). The EDTA-infusion induced hypocalcemia and hypophosphatemia. The HYP-, DPD- and ICTP-concentration remained mainly unaffected during both infusions. Only DPD showed an increase during infusion and HYP an increase 2 days after the infusion. In conclusion, the EDTA infusion had little effect on the concentrations of the measured bone markers, which may be due to the fact that the serum calcium pool was refilled by increased absorption of Ca via the gastrointestinal tract. From these results, it can be concluded that bone resorption was not influenced by EDTA infusion.

  20. Comparison among the methods for hydrogen peroxide measurements to evaluate advanced oxidation processes: Application of a spectrophotometric method using copper(II) ion and 2,9-dimethyl-1,10-phenanthroline

    SciTech Connect

    Kosaka, Koji; Yamada, Harumi; Matsui, Saburo; Echigo, Shinya; Shishida, Kenichi

    1998-12-01

    Hydrogen peroxide (H{sub 2}O{sub 2}) in the range of several tens to several hundreds of micromoles per liter is usually added to the process water in advanced oxidation processes (AOPs). In this study, a spectrophotometric method using copper(II) ion and 2,9-dimethyl-1, 10-phenanthroline (DMP) for measuring H{sub 2}O{sub 2} concentration was compared with other methods [i.e., spectrophotometric methods using titanium oxalate and N,N-diethyl-p-phenylenediamine (DPD) and a fluorometric method using p-hydroxyphenyl acetic acid (POHPAA)]. Particular attention was paid to sensitivities and effects of coexisting substances. The most sensitive method was the fluorometric method, followed in order by DPD, DMP, and the titanium oxalate colorimetric method; their detection limits in 1-cm cells were 0.16, 0.77, 0.80, and 29 {micro}M, respectively. Therefore, the DMP method was found to be reasonably sensitive when applied to AOPs. In the DMP method, copper(II)-DMP complexes react with humic acid, and colored chemicals are produced. However, the slopes of the calibration curves of H{sub 2}O{sub 2} containing up to 10 mg of C L{sup {minus}1} from humic acid did not change significantly as compared to that in ultrapure water. The effect of chlorine on the DMP method was not observed up to at least 23 {micro}M (0.8 mg of Cl L{sup {minus}1}) of free chlorine, although the DPD and fluorometric methods are known to be interfered by chlorine. From this study, it was concluded that the DMP method is suitable to be used in AOPs.

  1. Predicting dynamics and rheology of blood flow: A comparative study of multiscale and low-dimensional models of red blood cells

    PubMed Central

    Pan, Wenxiao; Fedosov, Dmitry A.; Caswell, Bruce; Karniadakis, George Em

    2011-01-01

    We compare the predictive capability of two mathematical models for red blood cells (RBCs) focusing on blood flow in capillaries and arterioles. Both RBC models as well as their corresponding blood flows are based on the dissipative particle dynamics (DPD) method, a coarse-grained molecular dynamics approach. The first model employs a multiscale description of the RBC (MS-RBC), with its membrane represented by hundreds or even thousands of DPD-particles connected by springs into a triangular network in combination with out-of-plane elastic bending resistance. Extra dissipation within the network accounts for membrane viscosity, while the characteristic biconcave RBC shape is achieved by imposition of constraints for constant membrane area and constant cell volume. The second model is based on a low-dimensional description (LD-RBC) constructed as a closed torus-like ring of only 10 large DPD colloidal particles. They are connected into a ring by worm-like chain (WLC) springs combined with bending resistance. The LD-RBC model can be fitted to represent the entire range of nonlinear elastic deformations as measured by optical-tweezers for healthy and for infected RBCs in malaria. MS-RBCs suspensions model the dynamics and rheology of blood flow accurately for any vessel size but this approach is computationally expensive for vessel diameters above 100 microns. Surprisingly, the much more economical suspensions of LD-RBCs also capture the blood flow dynamics and rheology accurately except for small-size vessels comparable to RBC diameter. In particular, the LD-RBC suspensions are shown to properly capture the experimental data for the apparent viscosity of blood and its cell-free layer (CFL) in tube flow. Taken together, these findings suggest a hierarchical approach in modeling blood flow in the arterial tree, whereby the MS-RBC model should be employed for capillaries and arterioles below 100 microns, the LD-RBC model for arterioles, and the continuum description for

  2. The role of Sp1 and Sp3 in the constitutive DPYD gene expression.

    PubMed

    Zhang, Xue; Li, Lin; Fourie, Jeanne; Davie, James R; Guarcello, Vincenzo; Diasio, Robert B

    2006-05-01

    Dihydropyrimidine dehydrogenase (DPD), the initial and rate-limiting enzyme in the 5-fluorouracil (5-FU) catabolic pathway, has been implicated as one of the factors determining the efficacy and toxicity of the anticancer agent 5-FU. Studies have attributed variation in DPD activity partially to alterations at the transcriptional level of DPYD gene. We investigated the transcription factors implicated in the constitutive expression of DPYD by utilizing a 174-bp fragment of the DPYD promoter region in which three consensus Sp protein binding sites (SpA, SpB and SpC) were predicted. The binding of Sp1 and Sp3 transcription factors to this region was detected by electrophoretic mobility shift and chromatin immunoprecipitation assays. By ectopically expressing human Sp1 and Sp3 in Sp-deficient Drosophila S2 cells, we demonstrated that Sp1 is a strong activator, while Sp3 by its own is a weak activator of the DPYD promoter. Moreover, Sp3 may serve as a competitor of Sp1, thus decreasing the Sp1 induced promoter activity. SpA, SpB and SpC sites are all Sp1 inducible. In the full activation of the DPYD promoter in human cell lines, the SpB site is essential; the SpC site works cooperatively with SpB, while SpA has minor promoter activity. These studies provide further insight into the molecular mechanisms underlying the heterogeneity of DPD activity, and may facilitate the efficacy and safety of 5-FU-based chemotherapy.

  3. Self-assembly in Nafion membranes upon hydration: water mobility and adsorption isotherms.

    PubMed

    Vishnyakov, Aleksey; Neimark, Alexander V

    2014-09-25

    By means of dissipative particle dynamics (DPD) and Monte Carlo (MC) simulations, we explored geometrical, transport, and sorption properties of hydrated Nafion-type polyelectrolyte membranes. Composed of a perfluorinated backbone with sulfonate side chains, Nafion self-assembles upon hydration and segregates into interpenetrating hydrophilic and hydrophobic subphases. This segregated morphology determines the transport properties of Nafion membranes that are widely used as compartment separators in fuel cells and other electrochemical devices, as well as permselective diffusion barriers in protective fabrics. We introduced a coarse-grained model of Nafion, which accounts explicitly for polymer rigidity and electrostatic interactions between anionic side chains and hydrated metal cations. In a series of DPD simulations with increasing content of water, a classical percolation transition from a system of isolated water clusters to a 3D network of hydrophilic channels was observed. The hydrophilic subphase connectivity and water diffusion were studied by constructing digitized replicas of self-assembled morphologies and performing random walk simulations. A non-monotonic dependence of the tracer diffusivity on the water content was found. This unexpected behavior was explained by the formation of large and mostly isolated water domains detected at high water content and high equivalent polymer weight. Using MC simulations, we calculated the chemical potential of water in the hydrated polymer and constructed the water sorption isotherms, which extended to the oversaturated conditions. We determined that the maximum diffusivity and the onset of formation of large water domains corresponded to the saturation conditions at 100% humidity. The oversaturated membrane morphologies generated in the canonical ensemble DPD simulations correspond to the metastable and unstable states of Nafion membrane that are not realized in the experiments.

  4. Collagen degradation products and proinflammatory cytokines in systemic and localized scleroderma.

    PubMed

    Becvár, R; Hulejová, H; Braun, M; Stork, J

    2007-01-01

    The aim of this study was to assess the degradation of collagen type I and proinflammatory cytokines in systemic and localized scleroderma compared with psoriasis and healthy controls. Total 99 individuals were examined - 24 with SSc, 22 with LSc, 39 patients with PsV and 14 healthy controls. U-PD and U-DPD were measured using a sensitive isocratic HPLC method. Serum levels of IL-6 and soluble IL-2R were assayed using commercial ELISA kits. In the SSc group U-PD and U-DPD levels (nmol/mmol creatinine) were increased compared with controls (P = 0.001) and with PsV (P = 0.006). IL-6 levels were increased compared with controls (P = 0.004) and with PsV (P = 0.002). IL-2R concentrations were insignificantly increased in comparison with controls and were lower than in PsV, but the difference was not significant. In the LSc group excretion of U-PD and U-DPD did not differ from controls, but was insignificantly decreased compared with PsV. IL-6 levels were increased compared with controls (P = 0.001) and also with PsV (P = 0.03). IL-2R concentrations were significantly increased in comparison with controls only (P = 0.03). In patients with SSc our data have shown the most intensive collagen degradation and simultaneously an active inflammation, as documented by IL-6, which reflects the pathological processes in the skin and visceral organs compared with PsV patients and healthy individuals. In the LSc group collagen degradation was similar to that in control groups, but a certain inflammatory activity was observed.

  5. Effects of raloxifene and estradiol on bone turnover parameters in intact and ovariectomized rats.

    PubMed

    Canpolat, S; Tug, N; Seyran, A D; Kumru, S; Yilmaz, B

    2010-03-01

    This study was designed to investigate effects of raloxifene (RLX) and estradiol on bone formation and resorption in intact and ovariectomized (ovx) rat models. In the intact model, a total of 24 adult female rats were divided into three groups: Controls subcutaneously received saline alone. RLX (2 mg/kg) and estradiol (30 microg/kg) were injected to two groups of animals for a period of 6 weeks at two daily intervals. In the second model, rats (n = 24) were ovx and allowed to recover for a period of at least 3 weeks. Control group received vehicle alone. Remaining rats were divided into two groups and injected with RLX (2 mg/kg) and estradiol (30 microg/kg) for 6 weeks. Urine samples were collected from all animals 24 h after the last drug administration. Urinary deoxypyridinoline (DPD) was measured by ELISA. Serum parathyroid hormone (PTH), calcitonin, and osteocalcin levels were measured by immunoradiometric method. Serum concentrations of alkaline phosphatase (ALP), Ca, and inorganic phosphate were determined by enzymatic-colorimetric method. Lumbar vertebrae (L2) of all animals were dissected out and processed for histopathological evaluation. Removal of ovaries significantly elevated urinary DPD levels (p < 0.01) compared with intact controls. Treatment of both intact and ovx rats with estradiol resulted in significant decreases (p < 0.01) in DPD values. RLX administration had no significant effect in the intact rats, but it remarkably reduced bone turnover in the ovx animals (p < 0.001). Both estradiol and RLX produced conflicting effects on serum ALP, osteocalcin, and PTH levels in both animal models. These findings suggest that RLX exerts its protective effects by reducing bone resorption, similar to that of estradiol, in ovx rats.

  6. Force Sensor-less Workspace Virtual Impedance Control Considering Resonant Vibration for Industrial Robot

    NASA Astrophysics Data System (ADS)

    Tungpataratanawong, Somsawas; Ohishi, Kiyoshi; Miyazaki, Toshimasa; Katsura, Seiichiro

    The motion control paradigm provides sufficient performance in many elementary industrial tasks. However, only stiff motion the robot cannot accommodate the interaction force under constrained motion. In such situation, the robot is required to perform interaction behavior with the environment. The conventional impedance control schemes require force-sensing devices to feedback force signals to the controllers. The force-sensing device is therefore indispensable and the performance of the system also depends on the quality of this device. This paper proposes a novel strategy for force sensor-less impedance control using disturbance observer and dynamic model of the robot to estimate the external force. In motion task, the robust D-PD (derivative-PD) control is used with feedforward inverse-dynamic torque compensation to ensure robustness and high-speed response with flexible joint model. When robot is in contact with environment, the proposed force sensor-less scheme impedance control with inner-loop D-PD control is utilized. D-PD control uses both position and speed as the references to implement the damping and stiffness characteristic of the virtual impedance model. In addition, the gravity and friction force-feedback compensation is computed by the same dynamic model, which is used in external force estimation. The flexible-joint robot model is utilized in both disturbance observer and motion control design. The workspace impedance control for robot interaction with human operator is implemented on the experimental setup three-degree-of-freedom (3-DOF) robot manipulator to assure the ability and performance of the proposed force sensor-less scheme for flexible-joint industrial robot.

  7. Feasibility of ecological momentary assessment to characterize adolescent postoperative diet and activity patterns after weight loss surgery.

    PubMed

    Ratcliff, Megan B; Zeller, Meg H; Inge, Thomas H; Hrovat, Kathleen B; Modi, Avani C

    2014-01-01

    Adherence to postoperative lifestyle recommendations may be associated with weight outcomes among weight loss surgery (WLS) patients, but it is difficult to objectively assess and has not been reported among adolescents. Methods of assessment that are ecologically valid and provide important contextual information related to adherence are needed. The objective of this pilot study was to demonstrate the feasibility of using a form of ecological momentary assessment (i.e., daily phone diaries; DPD) to assess postoperative diet and activity patterns among a sample of adolescent WLS patients to determine adherence to best-practice lifestyle recommendations. University Hospital. Eight adolescent WLS patients completed 3 consecutive DPDs at 12 and 18 months postsurgery. Ninety-four percent of DPD's were completed with an average 20.9 ± 5.0 activities/day. Although adolescents engaged in recommended lifestyle behaviors (e.g.,≥ 30 min moderate physical activity/d; duration of meals/snacks ≥ 20 min) some of the time, few were adherent to postoperative physical activity and dietary recommendations the majority of the time. The DPD provides a feasible and informative methodology for assessing adherence behaviors among adolescent WLS patients. It is a relatively low burden method that may be useful in identifying behavioral targets for postoperative intervention. Adherence to postoperative lifestyle recommendations may be a serious concern among this cohort. These preliminary data shed light on potential targets for postoperative intervention. Targeting nonadherence is essential in not only improving health outcomes but in deciphering the true potential effectiveness of WLS in this at-risk population. Copyright © 2014 American Society for Metabolic and Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

  8. Variability of collagen crosslinks: impact of sample collection period

    NASA Technical Reports Server (NTRS)

    Smith, S. M.; Dillon, E. L.; DeKerlegand, D. E.; Davis-Street, J. E.

    2004-01-01

    Because of the variability of collagen crosslinks, their use as markers for bone resorption is often criticized. We hypothesized that the variability could be reduced by collecting urine for 24 hours (or longer) instead of using single voids, and by not normalizing to creatinine. Urine samples were collected from 22 healthy subjects during two or more 24-hour periods. Each 24-hour pool and each 2nd void of the day were analyzed for N-telopeptide (NTX), pyridinium (PYD), and deoxypyridinoline (DPD) crosslinks. Data were analyzed by using linear regression. For NTX, R2 for the two, 2nd-void samples (n = 38) was 0.55, whereas R2 for the two 24-hour pools was 0.51 or 0.52, expressed per day or per creatinine. For PYD and DPD, R2 for the 2nd-void samples was 0.26 and 0.18, R2 for the 24-hour pools expressed per day was 0.58 and 0.74, and R2 for the 24-hour pools expressed per creatinine was 0.65 and 0.76, respectively. Regression of the 2nd void and the corresponding 24-hour pool, expressed per day, yielded R2 = 0.19, 0.19, and 0.08, for NTX, PYD, and DPD, respectively (n = 76 each). For the 2nd-void sample and its corresponding 24-hour pool, expressed per creatinine, R2 = 0.24, 0.33, and 0.08, respectively. In a separate study, the coefficient of variation for NTX was reduced (P < 0.05) when data from more than one 24-hour collection were combined. Thus, the variability inherent in crosslink determinations can be reduced by collecting urine for longer periods. In research studies, the high variability of single-void collections, compounded by creatinine normalization, may alter or obscure findings.

  9. Predicting dynamics and rheology of blood flow: A comparative study of multiscale and low-dimensional models of red blood cells

    SciTech Connect

    Pan, Wenxiao; Fedosov, Dmitry A.; Caswell, Bruce; Karniadakis, George E.

    2011-05-27

    In this work we compare the predictive capability of two mathematical models for red blood cells (RBCs) focusing on blood flow in capillaries and arterioles. Both RBC models as well as their corresponding blood flows are based on the dissipative particle dynamics (DPD) method, a coarse-grained molecular dynamics approach. The first model employs a multiscale description of the RBC (MS-RBC), with its membrane represented by hundreds or even thousands of DPD-particles connected by springs into a triangular network in combination with out-of-plane elastic bending resistance. Extra dissipation within the network accounts for membrane viscosity, while the characteristic biconcave RBC shape is achieved by imposition of constraints for constant membrane area and constant cell volume. The second model is based on a low-dimensional description (LD-RBC) constructed as a closed torus-like ring of only 10 large DPD colloidal particles. They are connected into a ring by worm-like chain (WLC) springs combined with bending resistance. The LD-RBC model can be fitted to represent the entire range of nonlinear elastic deformations as measured by optical-tweezers for healthy and for infected RBCs in malaria. MS-RBCs suspensions model the dynamics and rheology of blood flow accurately for any size vessel but this approach is computationally expensive above 100 microns. Surprisingly, the much more economical suspensions of LD-RBCs also capture the blood flow dynamics and rheology accurately except for vessels with sizes comparable to RBC diameter. In particular, the LD-RBC suspensions are shown to properly capture the experimental data for the apparent viscosity of blood and its cell-free layer (CFL) in tube flow. Taken together, these findings suggest a hierarchical approach in modeling blood flow in the arterial tree, whereby the MS-RBC model should be employed for capillaries and arterioles below 100 microns, the LD-RBC model for arterioles, and the continuum description for

  10. Changes in markers of bone formation and resorption in a bed rest model of weightlessness

    NASA Technical Reports Server (NTRS)

    Lueken, S. A.; Arnaud, S. B.; Taylor, A. K.; Baylink, D. J.

    1993-01-01

    To study the mechanism of bone loss in physical unloading, we examined indices of bone formation and bone resorption in the serum and urine of eight healthy men during a 7 day -6 degrees head-down tilt bed rest. Prompt increases in markers of resorption--pyridinoline (PD), deoxypyridinoline (DPD), and hydroxyproline (Hyp)/g creatinine--during the first few days of inactivity were paralleled by tartrate-resistant acid phosphatase (TRAP) with significant increases in all these markers by day 4 of bed rest. An index of formation, skeletal alkaline phosphatase (SALP), did not change during bed rest and showed a moderate 15% increase 1 week after reambulation. In contrast to SALP, serum osteocalcin (OC) began increasing the day preceding the increase in Hyp, remained elevated for the duration of the bed rest, and returned to pre-bed rest values within 5 days of reambulation. Similarly, DPD increased significantly at the onset of bed rest, remained elevated for the duration of bed rest, and returned to pre-bed rest levels upon reambulation. On the other hand, the other three indices of resorption, Hyp, PD, and TRAP, remained elevated for 2 weeks after reambulation. The most sensitive indices of the levels of physical activity proved to be the noncollagenous protein, OC, and the collagen crosslinker, DPD. The bed rest values of both these markers were significantly elevated compared to both the pre-bed rest values and the post-bed rest values. The sequence of changes in the circulating markers of bone metabolism indicated that increases in serum OC are the earliest responses of bone to head-down tilt bed rest.

  11. Olfactory Deficits in MCI as Predictor of Improved Cognition on Donepezil

    DTIC Science & Technology

    2015-04-01

    those of the author( s ) and should not be construed as an official Department of the Army position, policy or decision unless so designated by other...Improved Cognition on Donepezil. 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) Davangere Devanand, M.D. Betty Diamond 5d. PROJECT NUMBER...5e. TASK NUMBER E-Mail: dpd3@cumc.columbia.edu 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) AND ADDRESS(ES) 8

  12. The Fleischmann-Pons phenomenon; Different perspective

    SciTech Connect

    Ray, M.K.S.; Saini, R.D.; Das, D.; Chattopadhyay, G.; Parthasarathy, R.; Garg, S.P.; Venkataramani, R.; Sen, B.K.; Iyengar, T.S.; Kutty, K.K. )

    1992-11-01

    This paper reports on attempts which have been made to initiate the Fleischmann-Pons phenomenon through selective perturbations during experimental studies in divided electrolytic cells. Despite wide variations in the operating parameters and the attainment of high loading (sometimes up to D/Pd [approx] 2), the phenomenon was not observed either during the unperturbed electrolysis or on physical perturbation. However, instances of its occurrence were observed when the state of equilibrium of the deuterated cathode (having a scale free portion) was chemically perturbed by oxygen. This observation, viewed in light of available information, is indicative of oxygen playing a vital role in the phenomenon.

  13. Effect of berberine on bone mineral density in SAMP6 as a senile osteoporosis model.

    PubMed

    Li, Huiying; Miyahara, Tatsuro; Tezuka, Yasuhiro; Tran, Quan Le; Seto, Hikaru; Kadota, Shigetoshi

    2003-01-01

    The effects of berberine in senescence accelerated mice P6 (SAMP6) were investigated to learn whether the alkaloid affects bone mineral density (BMD). Oral administration of berberine (10 mg/kg/d) to male and female mice for 22 weeks resulted in an increase in BMD in both sexes. A decreased concentration of deoxypyridinoline (Dpd) in urine was only observed in female mice. There was no effect on body or tibia weight or on the concentration of procollagen type I carboxyterminal extension peptide (PICP) in serum.

  14. Immune Suppression and Inflammation in the Progression of Breast Cancer

    DTIC Science & Technology

    2008-03-01

    B220-PE, CD11c-PE, I-A/I-E-FITC, DPd P-FITC, CD86-PE, CD80-FITC, CD40-PE, CD44-FITC, CD14-FITC, CD23-FITC, CD31-FITC, CD34-FITC, CD16/ CD32 -FITC, rat...CD80 CD8 PDL2 CD16/ CD32 CD34 CD23 F4/80 DEC205 Log Fluorescence Gr1 4T1 MSC Isotype/Biotin Control 4T1/IL-1β MSC IL-1R A B CD11b G r1 4T1 4T1/IL-1β

  15. Recent Applications of Mesoscale Modeling to Nanotechnology and Drug Delivery

    SciTech Connect

    Maiti, A; Wescott, J; Kung, P; Goldbeck-Wood, G

    2005-02-11

    Mesoscale simulations have traditionally been used to investigate structural morphology of polymer in solution, melts and blends. Recently we have been pushing such modeling methods to important areas of Nanotechnology and Drug delivery that are well out of reach of classical molecular dynamics. This paper summarizes our efforts in three important emerging areas: (1) polymer-nanotube composites; (2) drug diffusivity through cell membranes; and (3) solvent exchange in nanoporous membranes. The first two applications are based on a bead-spring-based approach as encoded in the Dissipative Particle Dynamics (DPD) module. The last application used density-based Mesoscale modeling as implemented in the Mesodyn module.

  16. Current Development of Anti-Cancer Drug S-1

    PubMed Central

    Giri, Anil; Shakya, Suraj; Shakya, Sujana; Sapkota, Binaya; Pramod, KC

    2016-01-01

    S-1 is a novel oral fluoropyrimidine derivative, widely used for treating gastric, pancreatic, lung, head, neck and breast carcinomas. It is designed to enhance the clinical utility of an oral fluoropyrimidine and is associated with low gastrointestinal toxicity. S-1 consists of three pharmacological agents (at a molar ratio of 1:0.4:1)-Tegafur (FT), a prodrug of 5-Fluorouracil (5-FU), 5-Chloro-2-4-Dihydroxypyridine (CDHP), which inhibits the activity of Dihydropyrimidine Dehydrogenase (DPD) and Oxonic Acid (Oxo), which reduces Gastrointestinal (GI) toxicity of 5-FU. The present article reviews the current development of clinical study of S-1. PMID:28050491

  17. Effects of food enriched with egg yolk hydrolysate (bone peptide) on bone metabolism in orchidectomized dogs.

    PubMed

    Kobayashi, Toyokazu; Koie, Hiroshi; Watanabe, Arisa; Ino, Arisa; Watabe, Kazuya; Kim, Mujo; Kanayama, Kiichi; Otsuji, Kazuya

    2015-04-01

    We examined the effects of chicken egg hydrolysate (also known as "bone peptide" or BP) on bone metabolism in 5- to 8-month-old orchidectomized dogs. The bone formation marker serum bone alkaline phosphatase (BAP) and the bone resorption marker urine deoxypyridinoline (DPD) were used as indicators to measure changes in bone metabolism. The following results were observed that Serum BAP was higher in dogs fed BP-enriched food throughout the clinical investigation. Serum BAP was statistically significantly higher in dogs fed BP-enriched food than in dogs fed non-BP-enriched food at 2 months after orchidectomy. This suggests that BP promoted bone formation immediately after orchidectomy.

  18. A test of systematic coarse-graining of molecular dynamics simulations: Transport properties.

    PubMed

    Fu, Chia-Chun; Kulkarni, Pandurang M; Shell, M Scott; Leal, L Gary

    2013-09-07

    To what extent can a "bottom-up" mesoscale fluid model developed through systematic coarse-graining techniques recover the physical properties of a molecular scale system? In a previous paper [C.-C. Fu, P. M. Kulkarni, M. S. Shell, and L. G. Leal, J. Chem. Phys. 137, 164106 (2012)], we addressed this question for thermodynamic properties through the development of coarse-grained (CG) fluid models using modified iterative Boltzmann inversion methods that reproduce correct pair structure and pressure. In the present work we focus on the dynamic behavior. Unlike the radial distribution function and the pressure, dynamical properties such as the self-diffusion coefficient and viscosity in a CG model cannot be matched during coarse-graining by modifying the pair interaction. Instead, removed degrees of freedom require a modification of the equations of motion to simulate their implicit effects on dynamics. A simple but approximate approach is to introduce a friction coefficient, γ, and random forces for the remaining degrees of freedom, in which case γ becomes an additional parameter in the coarse-grained model that can be tuned. We consider the non-Galilean-invariant Langevin and the Galilean-invariant dissipative particle dynamics (DPD) thermostats with CG systems in which we can systematically tune the fraction φ of removed degrees of freedom. Between these two choices, only DPD allows both the viscosity and diffusivity to match a reference Lennard-Jones liquid with a single value of γ for each degree of coarse-graining φ. This friction constant is robust to the pressure correction imposed on the effective CG potential, increases approximately linearly with φ, and also depends on the interaction cutoff length, rcut, of the pair interaction potential. Importantly, we show that the diffusion constant and viscosity are constrained by a simple scaling law that leads to a specific choice of DPD friction coefficient for a given degree of coarse-graining. Moreover, we

  19. A test of systematic coarse-graining of molecular dynamics simulations: Transport properties

    NASA Astrophysics Data System (ADS)

    Fu, Chia-Chun; Kulkarni, Pandurang M.; Shell, M. Scott; Leal, L. Gary

    2013-09-01

    To what extent can a "bottom-up" mesoscale fluid model developed through systematic coarse-graining techniques recover the physical properties of a molecular scale system? In a previous paper [C.-C. Fu, P. M. Kulkarni, M. S. Shell, and L. G. Leal, J. Chem. Phys. 137, 164106 (2012)], 10.1063/1.4759463, we addressed this question for thermodynamic properties through the development of coarse-grained (CG) fluid models using modified iterative Boltzmann inversion methods that reproduce correct pair structure and pressure. In the present work we focus on the dynamic behavior. Unlike the radial distribution function and the pressure, dynamical properties such as the self-diffusion coefficient and viscosity in a CG model cannot be matched during coarse-graining by modifying the pair interaction. Instead, removed degrees of freedom require a modification of the equations of motion to simulate their implicit effects on dynamics. A simple but approximate approach is to introduce a friction coefficient, γ, and random forces for the remaining degrees of freedom, in which case γ becomes an additional parameter in the coarse-grained model that can be tuned. We consider the non-Galilean-invariant Langevin and the Galilean-invariant dissipative particle dynamics (DPD) thermostats with CG systems in which we can systematically tune the fraction ϕ of removed degrees of freedom. Between these two choices, only DPD allows both the viscosity and diffusivity to match a reference Lennard-Jones liquid with a single value of γ for each degree of coarse-graining ϕ. This friction constant is robust to the pressure correction imposed on the effective CG potential, increases approximately linearly with ϕ, and also depends on the interaction cutoff length, rcut, of the pair interaction potential. Importantly, we show that the diffusion constant and viscosity are constrained by a simple scaling law that leads to a specific choice of DPD friction coefficient for a given degree of coarse

  20. Osteogenesis Imperfecta, Pseudoachalasia, and Gastric Cancer

    PubMed Central

    Mizrak, Dilsa; Alkan, Ali; Erdogdu, Batuhan; Utkan, Gungor

    2015-01-01

    Osteogenesis imperfecta (OI) is a rare, inherited skeletal disorder characterized by abnormalities of type 1 collagen. Malignancy is rarely reported in patients with OI and it was suggested that this disease can protect against cancer. Here, we report a 41-year-old woman with symptoms of achalasia where repeated treatment of pneumatic dilation and stent replacement was unsuccessful; therefore, surgery was performed. Pathology showed gastric adenocarcinoma unexpectedly. Chemotherapy was given after assessing dihydropyrimidine dehydrogenase (DPD) enzyme activity, which can be deficient in OI patients. This is the first report of gastric cancer mimicking achalasia in a patient with OI. PMID:25874139

  1. Dissipative particle dynamics simulation on the self-assembly and disassembly of pH-sensitive polymeric micelle with coating repair agent

    NASA Astrophysics Data System (ADS)

    Wang, Xiumin; Gao, Jianbang; Wang, Zhikun; Xu, Jianchang; Li, Chunling; Sun, Shuangqing; Hu, Songqing

    2017-10-01

    Dissipative particle dynamics (DPD) simulations were applied to investigate the coating repair agent dicyclopentadience (DCPD) in pH-sensitive micelles. The results show micelles self-assembled from triblock copolymers with strong hydrophobic interaction are not conducive to loading DCPD, and only micelles with weak interaction parameter can encapsulate DCPD well. After protonation, the structure of micelle was disassembled and DCPD beads have a stronger ability to shrink polymer chains and exposed to water. This work provides mesoscopic insight into self-assembly and disassembly of desired agent-loaded micelle, and might be useful for the design of new materials for agent delivery.

  2. Conductivity of carbon nanotube polymer composites

    SciTech Connect

    Wescott, J T; Kung, P; Maiti, A

    2006-11-20

    Dissipative Particle Dynamics (DPD) simulations were used to investigate methods of controlling the assembly of percolating networks of carbon nanotubes (CNTs) in thin films of block copolymer melts. For suitably chosen polymers the CNTs were found to spontaneously self-assemble into topologically interesting patterns. The mesoscale morphology was projected onto a finite-element grid and the electrical conductivity of the films computed. The conductivity displayed non-monotonic behavior as a function of relative polymer fractions in the melt. Results are compared and contrasted with CNT dispersion in small-molecule fluids and mixtures.

  3. Effects of tumor necrosis factor-related apoptosis-inducing ligand alone and in combination with fluoropyrimidine anticancer agent, S-1, on tumor growth of human oral squamous cell carcinoma xenografts in nude mice.

    PubMed

    Itashiki, Yasutaka; Harada, Koji; Ferdous, Tarannum; Yoshida, Hideo

    2007-01-01

    Chemotherapy has shown little antitumor activity against advanced oral squamous cell carcinoma (OSCC) patients. Therefore, there is an urgent need to develop more effective therapeutic methods for patients with advanced OSCC. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the tumor necrosis factor ligand family that selectively induces apoptosis of cancer cells. S-1 is a new oral antineoplastic agent that can induce apoptosis in various types of cancer cells, including OSCC. Hence, combined treatment of cancer cells with TRAIL and S-1 might exert dramatic antitumor effects on OSCC cells. In this study, the response of human OSCC cells to TRAIL alone and in combination with S-1 was examined using nude mouse xenograft models. S-1 (10 mg/kg/day, 5 times/week) was administered orally and TRAIL (1 mg/kg, 5 times/week) was injected into peritumoral tissue for three weeks. Apoptotic cells were detected by a TUNEL method. The protein expression of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and orotate phosphoribosyl transferase (OPRT) were assessed using immunohistochemistry; their gene expression was determined using microdissection and RT-PCR, and their protein levels using ELISA. Combined therapy of TRAIL and S-1 exerted antitumor effects on human OSCC xenografts markedly and significantly induced apoptotic cells in tumors treated with TRAIL plus S-1. Immunohistochemistry showed that the expressions of TS and DPD were down-regulated, and that OPRT expression was up-regulated in tumors treated with TRAIL plus S-1. In the same way, microdissection and RT-PCR revealed that the expression of TS and DPD mRNA was down-regulated and that expression of OPRT mRNA was up-regulated in tumors administered the combined treatment. Moreover, ELISA indicated that the protein levels of TS and DPD were down-regulated, and that OPRT was up-regulated in tumors treated with the combined therapy. During the experimental period, no loss

  4. Dissipative-particle-dynamics model of biofilm growth

    SciTech Connect

    Xu, Zhijie; Meakin, Paul; Tartakovsky, Alexandre M.; Scheibe, Timothy D.

    2011-06-13

    A dissipative particle dynamics (DPD) model for the quantitative simulation of biofilm growth controlled by substrate (nutrient) consumption, advective and diffusive substrate transport, and hydrodynamic interactions with fluid flow (including fragmentation and reattachment) is described. The model was used to simulate biomass growth, decay, and spreading. It predicts how the biofilm morphology depends on flow conditions, biofilm growth kinetics, the rheomechanical properties of the biofilm and adhesion to solid surfaces. The morphology of the model biofilm depends strongly on its rigidity and the magnitude of the body force that drives the fluid over the biofilm.

  5. Recommendations for Creating a Resource Management System to Support the Colombian Army in a New Environment

    DTIC Science & Technology

    1992-04-15

    1.4 percent of GNP versus 6.1 for Europe, 5.9 for the United States, and 4.2 for Africa (figures of military expenditures, 1988 ). 4 The result is...Colombia: Political Constitution of 1991, FBIS-LAT-91-170-S, 3 September 1991. 7. Presidencia de la Republica, Estrategia Nacional Contra la Violencia, El...Russack, 1973. Presidencia de la Republica, Colombia, Estrategia Nacional contra la Violencia, El Tiempo Newspaper, Supplement, May 1991. Quade, E

  6. Rheological properties of Cubic colloidal suspensions

    NASA Astrophysics Data System (ADS)

    Boromand, Arman; Maia, Joao

    2016-11-01

    Colloidal and non-colloidal suspensions are ubiquitous in many industrial application. There are numerous studies on these systems to understand and relate their complex rheological properties to their microstructural evolution under deformation. Although most of the experimental and simulation studies are centered on spherical particles, in most of the industrial applications the geometry of the colloidal particles deviate from the simple hard sphere and more complex geometries exist. Recent advances in microfabrication paved the way to fabricate colloidal particles with complex geometries for applications in different areas such as drug delivery where the fundamental understanding of their dynamics has remained unexplored. In this study, using dissipative particle dynamics, we investigate the rheological properties of cubic (superball) particles which are modeled as the cluster of core-modified DPD particles. Explicit representation of solvent particles in the DPD scheme will conserve the full hydrodynamic interactions between colloidal particles. Rheological properties of these cubic suspensions are investigated in the dilute and semi-dilute regimes. The Einstein and Huggins coefficients for these particles with different superball exponent will be calculate which represent the effect of single particle's geometry and multibody interactions on viscosity, respectively. The response of these suspensions is investigated under simple shear and oscillatory shear where it is shown that under oscillation these particles tend to form crystalline structure giving rise to stronger shear-thinning behavior recently measured experimentally.

  7. Limitations of three-dimensional power Doppler angiography in preoperative evaluation of ovarian tumors.

    PubMed

    Silvestre, Liliane; Martins, Wellington P; Candido-Dos-Reis, Francisco J

    2015-07-29

    This study describes the accuracy of three-dimensional power Doppler (3D-PD) angiography as secondary method for differential diagnosis of ovarian tumors. Seventy-five women scheduled for surgical removal of adnexal masses were assessed by transvaginal ultrasound. Ovarian tumors were classified by IOTA simple rules and two three-dimensional blocks were recorded. In a second step analyses, a 4 cm(3) spherical sample was obtained from the highest vascularized solid area of each stored block. Vascularization index (VI), flow index (FI) and vascularization-flow index (VFI) were calculated. The repeatability was assessed by concordance correlation coefficient (CCC) and limits of agreement (LoA), and diagnostic accuracy by area under ROC curve. IOTA simple rules classified 26 cases as benign, nine as inconclusive and 40 as malignant. There were eight false positive and no false negative. Among the masses classified as inconclusive or malignant by IOTA simple rules, the CCCs were 0.91 for VI, 0.70 for FI, and 0.86 for VFI. The areas under ROC curve were 0.82 for VI, 0.67 for FI and 0.81 for VFI. 3D-PD angiography presented considerable intraobserver variability and low accuracy for identifying false positive results of IOTA simple rules.

  8. Sorivudine and 5-fluorouracil; a clinically significant drug-drug interaction due to inhibition of dihydropyrimidine dehydrogenase

    PubMed Central

    Diasio, Robert B

    1998-01-01

    Sorivudine (1-β-d-arabinofuranosyl-E-5-[2-bromovinyl] uracil; BV-araU; SQ32,756) is an antimetabolite which is a synthetic analogue of thymidine. This drug has demonstrated antiviral activity against varicella zoster virus, herpes simplex type 1 virus, and Epstein-Barr virus. Clinical studies in Japan and subsequently worldwide showed this drug to be a potent agent for treating varicella zoster infections. Although in general well tolerated, a fatal drug interaction with fluoropyrimidine drugs was subsequently observed. While three deaths resulting from this interaction were recognized to have occurred during the initial clinical evaluation in Japan, the full impact of the interaction was not recognized in Japan until post-marketing when an additional 23 cases of severe toxicity were reported including 16 patients who subsequently died from fluoro-pyrimidine toxicity. Worldwide recognition of this potentially fatal drug-drug interaction led to subsequent disapproval in the US and elsewhere. The interaction has been shown to be due to suppression of 5-fluorouracil (5-FU) catabolism, resulting in higher levels of 5-FU than would normally be observed. The mechanism of this interaction is mediated through inhibition of the 5-FU rate-limiting catabolizing enzyme dihydropyrimidine dehydrogenase (DPD) by the BV-araU metabolite BVU. This drug-drug interaction of sorivudine and 5-FU further emphasizes the critical importance of DPD on the clinical pharmacology of 5-FU. PMID:9690942

  9. A combination of biochemical markers of cartilage and bone turnover, radiographic damage and body mass index to predict the progression of joint destruction in patients with rheumatoid arthritis treated with disease-modifying anti-rheumatic drugs.

    PubMed

    Hashimoto, Jun; Garnero, Patrick; van der Heijde, Désirée; Miyasaka, Nobuyuki; Yamamoto, Kazuhiko; Kawai, Shinichi; Takeuchi, Tsutomu; Yoshikawa, Hideki; Nishimoto, Norihiro

    2009-01-01

    The aim of this study was to evaluate the predictive value of biological, radiological and clinical parameters for the progression of radiographic joint damage in rheumatoid arthritis (RA) patients treated with conventional disease-modifying anti-rheumatic drugs (DMARDs). We analyzed the 145 patients with active RA for less than 5 years who were participating in the prospective 1-year randomized controlled trial of tocilizumab (SAMURAI trial) as a control arm treated with conventional DMARDs. Progression of joint damage was assessed by sequential radiographs read by two independent blinded X-ray readers and scored for bone erosion and joint space narrowing (JSN) using the van der Heijde-modified Sharp method. Multivariate analysis revealed that increased urinary levels of C-terminal crosslinked telopeptide of type II collagen (U-CTX-II), an increased urinary total pyridinoline/total deoxypyridinoline (U-PYD/DPD) ratio and low body mass index (BMI) at baseline were independently associated with a higher risk for progression of bone erosion. In addition to these three variables, the JSN score at baseline was also significantly associated with an increased risk of progression of the JSN score and total Sharp score. High baseline U-CTX-II levels, U-PYD/DPD ratio and JSN score and a low BMI are independent predictive markers for the radiographically evident joint damage in patients with RA treated with conventional DMARDs.

  10. Measurements of excess heat from a Pons-Fleischmann-type electrolytic cell using palladium sheet

    SciTech Connect

    Storms, E. )

    1993-03-01

    Two pieces of palladium sheet similar to that used by Takahashi were loaded with deuterium in a Pons-Fleischmann-type electrolytic cell, and heat production was measured. One sheet produced a steady increase in excess power that reached 7.5 W (20% of input power) before the study was interrupted. A second similar sheet from a different batch of palladium did not produce any measurable excess power. There were differences in the loading behavior, the maximum stoichiometry, and the presence of excess volume in the deuteride made from these materials. The first sheet contained 0.8% excess volume after having been deloaded from its maximum deuterium/palladium (D/Pd) ratio of 0.82 to 0.73, and the second sheet contained 13.5% excess volume while at its maximum ratio of 0.75. The high excess volume in the latter case is an indication of internal escape paths that reduce the required high D/Pd ratio. 30 refs., 17 figs., 3 tabs.

  11. Graphene quantum dot as a green and facile sensor for free chlorine in drinking water.

    PubMed

    Dong, Yongqiang; Li, Geli; Zhou, Nana; Wang, Ruixue; Chi, Yuwu; Chen, Guonan

    2012-10-02

    Free chlorine was found to be able to destroy the passivated surface of the graphene quantum dots (GQDs) obtained by pyrolyzing citric acid, resulting in significant quenching of their fluorescence (FL) signal. After optimizing some experimental conditions (including response time, concentration of GQDs, and pH value of solution), a green and facile sensing system has been developed for the detection of free residual chlorine in water based on FL quenching of GQDs. The sensing system exhibits many advantages, such as short response time, excellent selectivity, wide linear response range, and high sensitivity. The linear response range of free chlorine (R(2) = 0.992) was from 0.05 to 10 μM. The detection limit (S/N = 3) was as low as 0.05 μM, which is much lower than that of the most widely used N-N-diethyl-p-phenylenediamine (DPD) colorimetric method. This sensing system was finally used to detect free residual chlorine in local tap water samples. The result agreed well with that by the DPD colorimetric method, suggesting the potential application of this new, green, sensitive, and facile sensing system in drinking water quality monitoring.

  12. Hybrid smoothed dissipative particle dynamics and immersed boundary method for simulation of red blood cells in flows.

    PubMed

    Ye, Ting; Phan-Thien, Nhan; Lim, Chwee Teck; Peng, Lina; Shi, Huixin

    2017-06-01

    In biofluid flow systems, often the flow problems of fluids of complex structures, such as the flow of red blood cells (RBCs) through complex capillary vessels, need to be considered. The smoothed dissipative particle dynamics (SDPD), a particle-based method, is one of the easy and flexible methods to model such complex structure fluids. It couples the best features of the smoothed particle hydrodynamics (SPH) and dissipative particle dynamics (DPD), with parameters having specific physical meaning (coming from SPH discretization of the Navier-Stokes equations), combined with thermal fluctuations in a mesoscale simulation, in a similar manner to the DPD. On the other hand, the immersed boundary method (IBM), a preferred method for handling fluid-structure interaction problems, has also been widely used to handle the fluid-RBC interaction in RBC simulations. In this paper, we aim to couple SDPD and IBM together to carry out the simulations of RBCs in complex flow problems. First, we develop the SDPD-IBM model in details, including the SDPD model for the evolving fluid flow, the RBC model for calculating RBC deformation force, the IBM for treating fluid-RBC interaction, and the solid boundary treatment model as well. We then conduct the verification and validation of the combined SDPD-IBM method. Finally, we demonstrate the capability of the SDPD-IBM method by simulating the flows of RBCs in rectangular, cylinder, curved, bifurcated, and constricted tubes, respectively.

  13. Multi-dimensional crest factor reduction and digital predistortion for multi-band radio-over-fiber links.

    PubMed

    Chen, Hao; Li, Jianqiang; Yin, Chunjing; Xu, Kun; Dai, Yitang; Yin, Feifei

    2014-08-25

    A multi-dimensional crest factor reduction (MD-CFR) technique is proposed to improve the performance and efficiency of multi-band radio-over-fiber (RoF) links. Cooperating with multi-dimensional digital predistortion (MD-DPD), MD-CFR increases the performance of both directly-modulated and externally-modulated RoF links, in terms of error vector magnitude (EVM) and adjacent channel power ratio (ACPR). For directly-modulated RoF link, more than 5 dB output ACPR reduction is obtained, output EVMs are reduced from 11.83% and 12.47% to 7.51% and 7.26% for two bands respectively, while only a slight improvement to 11.58% and 10.78% is obtained solely using MD-DPD. Similar results are achieved in externally-modulated RoF link. Given a threshold in EVM or ACPR, the RF power transmit efficiency is also further enhanced.

  14. Determination of rapid chlorination rate constants by a stopped-flow spectrophotometric competition kinetics method.

    PubMed

    Song, Dean; Liu, Huijuan; Qiang, Zhimin; Qu, Jiuhui

    2014-05-15

    Free chlorine is extensively used for water and wastewater disinfection nowadays. However, it still remains a big challenge to determine the rate constants of rapid chlorination reactions although competition kinetics and stopped-flow spectrophotometric (SFS) methods have been employed individually to investigate fast reaction kinetics. In this work, we proposed an SFS competition kinetics method to determine the rapid chlorination rate constants by using a common colorimetric reagent, N,N-diethyl-p-phenylenediamine (DPD), as a reference probe. A kinetic equation was first derived to estimate the reaction rate constant of DPD towards chlorine under a given pH and temperature condition. Then, on that basis, an SFS competition kinetics method was proposed to determine directly the chlorination rate constants of several representative compounds including tetracycline, ammonia, and four α-amino acids. Although Cl2O is more reactive than HOCl, its contribution to the overall chlorination kinetics of the test compounds could be neglected in this study. Finally, the developed method was validated through comparing the experimentally measured chlorination rate constants of the selected compounds with those obtained or calculated from literature and analyzing with Taft's correlation as well. This study demonstrates that the SFS competition kinetics method can measure the chlorination rate constants of a test compound rapidly and accurately.

  15. Dissipative particle dynamics simulations of the viscosities of molten TNT and molten TNT suspensions containing nanoparticles.

    PubMed

    Zhou, Yang; Li, Yixue; Qian, Wen; He, Bi

    2016-09-01

    Based on dissipative particle dynamics (DPD) methods and experimental data, we used an empirical relationship between the DPD temperature and the real temperature to build a model that describes the viscosity of molten TNT fluids. The errors in the predicted viscosity based on this model were no more than 2.3 %. We also studied the steady-state shear rheological behavior of molten TNT fluids containing nanoparticles ("nanofluids"). The dependence of the nanofluid viscosity on the temperature was found to satisfy an Arrhenius-type equation, η = Ae (B/T) , where B, the flow activation energy, depends on particle content, size, and shape. We modified the Einstein-type viscosity model to account for the effects of nanoparticle solvation in TNT nanofluids. The resulting model was able to correctly predict the viscosities of suspensions containing nano- to microsized particles, and did not require any changes to the physical background of Einstein's viscosity theory. Graphical Abstract The revised Einstein viscosity model that correctly predict the viscosity of TNT suspensions containing nanoparticles.

  16. Mesoscale Simulations and Experimental Studies of pH-Sensitive Micelles for Controlled Drug Delivery.

    PubMed

    Wang, Yan; Li, Qiu Yu; Liu, Xu Bo; Zhang, Can Yang; Wu, Zhi Min; Guo, Xin Dong

    2015-11-25

    The microstructures of doxorubicin-loaded micelles prepared from block polymers His(x)Lys10 (x = 0, 5, 10) conjugated with docosahexaenoic acid (DHA) are investigated under different pH conditions, using dissipative particle dynamics (DPD) simulations. The conformation of micelles and the DOX distributions in micelles were obviously influenced by pH values and the length of the histidine segment. At pH >6.0, the micelles self-assembled from the polymers were dense and compact. The drugs were entrapped well within the micellar core. The particle size increases as the histidine length increases. With the decrease of pH value to be lower than 6.0, there was no distinct difference for the micelles self-assembled from the polymer without histidine residues. However, the micelles prepared from the polymers with histidine residues shows a structural transformation from dense to swollen conformation, leading to an increased particle size from 10.3 to 14.5 DPD units for DHD-His10Lys10 micelles. This structural transformation of micelles can accelerate the DOX release from micelles under lower pH conditions. The in vitro drug release from micelles is accelerated by the decrease of pH value from 7.4 (physiological environment) to 5.0 (lysosomal environment). The integration of simulation and experiments might be a valuable method for the optimization and design of biomaterials for drug delivery with desired properties.

  17. Viscosity measurement techniques in Dissipative Particle Dynamics

    NASA Astrophysics Data System (ADS)

    Boromand, Arman; Jamali, Safa; Maia, Joao M.

    2015-11-01

    In this study two main groups of viscosity measurement techniques are used to measure the viscosity of a simple fluid using Dissipative Particle Dynamics, DPD. In the first method, a microscopic definition of the pressure tensor is used in equilibrium and out of equilibrium to measure the zero-shear viscosity and shear viscosity, respectively. In the second method, a periodic Poiseuille flow and start-up transient shear flow is used and the shear viscosity is obtained from the velocity profiles by a numerical fitting procedure. Using the standard Lees-Edward boundary condition for DPD will result in incorrect velocity profiles at high values of the dissipative parameter. Although this issue was partially addressed in Chatterjee (2007), in this work we present further modifications (Lagrangian approach) to the original LE boundary condition (Eulerian approach) that will fix the deviation from the desired shear rate at high values of the dissipative parameter and decrease the noise to signal ratios in stress measurement while increases the accessible low shear rate window. Also, the thermostat effect of the dissipative and random forces is coupled to the dynamic response of the system and affects the transport properties like the viscosity and diffusion coefficient. We investigated thoroughly the dependency of viscosity measured by both Eulerian and Lagrangian methodologies, as well as numerical fitting procedures and found that all the methods are in quantitative agreement.

  18. Hybrid smoothed dissipative particle dynamics and immersed boundary method for simulation of red blood cells in flows

    NASA Astrophysics Data System (ADS)

    Ye, Ting; Phan-Thien, Nhan; Lim, Chwee Teck; Peng, Lina; Shi, Huixin

    2017-06-01

    In biofluid flow systems, often the flow problems of fluids of complex structures, such as the flow of red blood cells (RBCs) through complex capillary vessels, need to be considered. The smoothed dissipative particle dynamics (SDPD), a particle-based method, is one of the easy and flexible methods to model such complex structure fluids. It couples the best features of the smoothed particle hydrodynamics (SPH) and dissipative particle dynamics (DPD), with parameters having specific physical meaning (coming from SPH discretization of the Navier-Stokes equations), combined with thermal fluctuations in a mesoscale simulation, in a similar manner to the DPD. On the other hand, the immersed boundary method (IBM), a preferred method for handling fluid-structure interaction problems, has also been widely used to handle the fluid-RBC interaction in RBC simulations. In this paper, we aim to couple SDPD and IBM together to carry out the simulations of RBCs in complex flow problems. First, we develop the SDPD-IBM model in details, including the SDPD model for the evolving fluid flow, the RBC model for calculating RBC deformation force, the IBM for treating fluid-RBC interaction, and the solid boundary treatment model as well. We then conduct the verification and validation of the combined SDPD-IBM method. Finally, we demonstrate the capability of the SDPD-IBM method by simulating the flows of RBCs in rectangular, cylinder, curved, bifurcated, and constricted tubes, respectively.

  19. Adaptive resolution simulations coupling atomistic water to dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Zavadlav, Julija; Praprotnik, Matej

    2017-09-01

    Multiscale methods are the most efficient way to address the interlinked spatiotemporal scales encountered in soft matter and molecular liquids. In the literature reported hybrid approaches span from quantum to atomistic, coarse-grained, and continuum length scales. In this article, we present the hybrid coupling of the molecular dynamics (MD) and dissipative particle dynamics (DPD) methods, bridging the micro- and mesoscopic descriptions. The interfacing is performed within the adaptive resolution scheme (AdResS), which is a linear momentum conserving coupling technique. Our methodology is hence suitable to simulate fluids on the micro/mesoscopic scale, where hydrodynamics plays an important role. The presented approach is showcased for water at ambient conditions. The supramolecular coupling is enabled by a recently developed clustering algorithm SWINGER that assembles, disassembles, and reassembles clusters as needed during the course of the simulation. This allows for a seamless coupling between standard atomistic MD and DPD models. The developed framework can be readily applied to various applications in the fields of materials and life sciences, e.g., simulations of phospholipids and polymer melts, or to study the red blood cells behavior in normal and disease states.

  20. GPU-accelerated red blood cells simulations with transport dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Blumers, Ansel L.; Tang, Yu-Hang; Li, Zhen; Li, Xuejin; Karniadakis, George E.

    2017-08-01

    Mesoscopic numerical simulations provide a unique approach for the quantification of the chemical influences on red blood cell functionalities. The transport Dissipative Particle Dynamics (tDPD) method can lead to such effective multiscale simulations due to its ability to simultaneously capture mesoscopic advection, diffusion, and reaction. In this paper, we present a GPU-accelerated red blood cell simulation package based on a tDPD adaptation of our red blood cell model, which can correctly recover the cell membrane viscosity, elasticity, bending stiffness, and cross-membrane chemical transport. The package essentially processes all computational workloads in parallel by GPU, and it incorporates multi-stream scheduling and non-blocking MPI communications to improve inter-node scalability. Our code is validated for accuracy and compared against the CPU counterpart for speed. Strong scaling and weak scaling are also presented to characterize scalability. We observe a speedup of 10 . 1 on one GPU over all 16 cores within a single node, and a weak scaling efficiency of 91% across 256 nodes. The program enables quick-turnaround and high-throughput numerical simulations for investigating chemical-driven red blood cell phenomena and disorders.

  1. Application of Dissipative Particle Dynamics to the Study of a Red Blood Cell in Simple Shear Flow

    NASA Astrophysics Data System (ADS)

    Ye, Ting; Phan-Thien, Nhan; Khoo, Boo Cheong; Lim, Chwee Teck

    2014-11-01

    The present work reports an attempt to apply the dissipative particle dynamics (DPD) method to study the dynamic behaviors of a red blood cell (RBC) in simple shear flow. The simulation system is discretized into four types of particles, namely wall particles, fluid particles, membrane particles and internal particles. The particle interaction is modeled by the DPD method, and the membrane particles are connected into a viscoelastic triangular network to represent the RBC membrane. As benchmarking tests, we simulate the deformation of a spherical capsule in shear flow and compare it with the past study, and also examine the effect of computational domain size. After that, we investigate the dynamics of a RBC in shear flow at different membrane shear and bending moduli. Our simulations reproduce the tank-treading, trembling and tumbling motions of the RBC at the shear modulus Es = 6, 60 and 600 μN/m, respectively. Moreover, we find that the RBC undergoes a trembling motion when its bending modulus is large enough, where the obvious stretching and smoothing of the RBC occur alternately in shape.

  2. A file of red blood cells in tube flow: A three-dimensional numerical study

    NASA Astrophysics Data System (ADS)

    Ye, Ting; Phan-Thien, Nhan; Khoo, Boo Cheong; Lim, Chwee Teck

    2014-09-01

    The rheology of a file of red blood cells (RBCs) in a tube flow is investigated based on a three-dimensional (3D) computational model using the dissipative particle dynamics (DPD) method. The 3D model consists of a discrete RBC model to describe the RBC deformation, a Morse potential model to characterize the cell-cell interaction, and a DPD model to provide all the relevant information on the suspension flow. Three important features of the suspension flow are simulated and analyzed, (i) the effect of the tube hematocrit, (ii) the effect of the cell spacing, and (iii) the effect of the flow velocity. We first study the cell deformation and the rheology of suspension at different tube hematocrit. The results show that the cell deformation decreases with increasing tube hematocrit, and a good agreement between the simulation and available experiments is found for the discharge hematocrit and relative apparent viscosity of RBC suspension. We then analyze the effect of non-uniform cell spacing, where the cell-cell interaction goes into effect, showing that a non-uniform cell spacing has a slight effect on the cell deformation, and almost has no effect on the rheology of suspension. We finally study the effect of the flow velocity and show that a typical plug-flow velocity profile is observed. The results also show that the cell deformation increases with increasing flow velocity, as expected. The discharge hematocrit also increases, but the relative apparent viscosity decreases, with increasing flow velocity.

  3. Simulation of a single red blood cell flowing through a microvessel stenosis using dissipative particle dynamics.

    PubMed

    Xiao, L L; Chen, S; Lin, C S; Liu, Y

    2014-03-01

    The motion and deformation of a single red blood cell flowing through a microvessel stenosis was investigated employing dissipative particle dynamics (DPD) method. The numerical model considers plasma, cytoplasm, the RBC membrane and the microvessel walls, in which a three dimensional coarse-grained spring RBC. The suspending plasma was modelled as an incompressible Newtonian fluid and the vessel walls were regarded as rigid body. The body force exerted on the free DPD particles was used to drive the flow. A modified bounce-back boundary condition was enforced on the membrane to guarantee the impenetrability. Adhesion of the cell to the stenosis vessel surface was mediated by the interactions between receptors and ligands. Firstly, the motion of a single RBC in a microfluidic channel was simulated and the results were found in agreement with the experimental data cited by [1]. Then the mechanical behavior of the RBC in the microvessel stenosis was studied. The effects of the bending rigidity of membrane, the size of the stenosis and the driven body force on the deformation and motion of red blood cell were discussed.

  4. Single droplet drying step characterization in microsphere preparation.

    PubMed

    Al Zaitone, Belal; Lamprecht, Alf

    2013-05-01

    Spray drying processes are difficult to characterize since process parameters are not directly accessible. Acoustic levitation was used to investigate microencapsulation by spray drying on one single droplet facilitating the analyses of droplet behavior upon drying. Process parameters were simulated on a poly(lactide-co-glycolide)/ethyl acetate combination for microencapsulation. The results allowed quantifying the influence of process parameters such as temperature (0-40°C), polymer concentration (5-400 mg/ml), and droplet size (0.5-1.37 μl) on the drying time and drying kinetics as well as the particle morphology. The drying of polymer solutions at temperature of 21°C and concentration of 5 mg/ml, shows that the dimensionless particle diameter (Dp/D0) approaches 0.25 and the particle needs 350 s to dry. At 400 mg/ml, Dp/D0=0.8 and the drying time increases to one order of magnitude and a hollow particle is formed. The study demonstrates the benefit of using the acoustic levitator as a lab scale method to characterize and study the microparticle formation. This method can be considered as a helpful tool to mimic the full scale spray drying process by providing identical operational parameters such as air velocity, temperature, and variable droplet sizes. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Low to moderate alcohol consumption on serum vitamin D and other indicators of bone health in postmenopausal women in a controlled feeding study.

    PubMed

    Mahabir, S; Baer, D J; Pfeiffer, R M; Li, Y; Watkins, B A; Taylor, P R

    2014-11-01

    The objective of this study was to evaluate the effect of 8 weeks of no alcohol, low (1 drink or 15 g/day) and moderate (2 drinks or 30 g/day) alcohol consumption on markers of bone health: fasting serum 25-hydroxy vitamin D (25(OH)D), osteocalcin (OC), bone-specific alkaline phosphatase (BSAP), urine deoxypyridinoline (DPD) and helical peptide (HP) in postmenopausal women (n=51). Compared with no alcohol, 1 or 2 drinks/day for 8 weeks had no significant impact on any of the bone markers. Within each alcohol group, obese women had significantly lower serum 25(OH)D and higher DPD concentrations than normal weight women. Season significantly affected the concentrations of serum 25(OH)D, but there was no significant interaction between alcohol and season on serum 25(OH)D concentrations. Low or moderate alcohol consumption for 8 weeks had no significant impact on markers of bone health in postmenopausal women.

  6. Three-dimensional ultrasound evaluation of the placenta.

    PubMed

    Hata, T; Tanaka, H; Noguchi, J; Hata, K

    2011-02-01

    Conventional two-dimensional (2D) ultrasound has been widely used for the evaluation of the placenta during pregnancy. This 2D ultrasound evaluation includes the morphology, anatomy, location, implantation, anomaly, size, and color/power and pulsed Doppler sonographic assessment of the placenta. The introduction of three-dimensional (3D) ultrasound would facilitate the novel assessment of the placenta, such as surface-rendered imaging and volume measurement. With the recent advances in 3D power Doppler (3DPD) ultrasound as well as quantitative 3DPD histogram analysis, quantitative and qualitative assessments of the vascularization and blood flow of the placenta have become feasible. These novel techniques may assist in the evaluation of the feto-placental function, and offer potential advantages relative to conventional 2D sonographic assessments. 3D ultrasound may be an important modality in future placental research, in the evaluation of feto-placental insufficiency in clinical practice, and in the prediction of fetal growth restriction and pre-eclampsia, although some limitations regarding the assessment of the placenta employing 3D ultrasound still remain unresolved. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. Counterintuitive cooperative endocytosis of like-charged nanoparticles in cellular internalization: computer simulation and experiment.

    PubMed

    Li, Ye; Yuan, Bing; Yang, Kai; Zhang, Xianren; Yan, Bing; Cao, Dapeng

    2017-02-24

    The nanoparticles (NPs) functionalized with charged ligands are of particular significance due to their potential drug/gene delivery and biomedical applications. However, the molecular mechanism of endocytosis of the charged NPs by cells, especially the effect of the NP-NP and NP-biomembrane interactions on the internalization pathways is still poorly understood. In this work, we systematically investigate the internalization behaviors of the positively charged NPs by combining experiment technology and dissipative particle dynamics (DPD) simulation. We experimentally find an interesting but highly counterintuitive phenomenon, i.e. the multiple positively charged NPs prefer to enter cells cooperatively although the like-charged NPs have obvious electrostatic repulsion. Furthermore, we adopt the DPD simulation to confirm the experimental findings, and reveal that the mechanism of the cooperative endocytosis between like-charged NPs is definitely caused by the interplay of particle size, the charged ligand density on particle surface and local concentration of NPs. Importantly, we not only observe the normal cooperative endocytosis of like-charged NPs in cell biomembrane like neutral NP case, but also predict the 'bud' cooperative endocytosis of like-charged NPs which is absence in the neutral NP case. The results indicate that electrostatic repulsion between the positively charged nanoparticles plays an important role in the 'bud' cooperative endocytosis of like-charged NPs.

  8. Environmental monitoring of ivermectin excreted in spring climatic conditions by treated cattle on dung fauna and degradation of faeces on pasture.

    PubMed

    Iglesias, Lucía E; Fusé, Luis A; Lifschitz, Adrián L; Rodríguez, Edgardo M; Sagüés, María F; Saumell, Carlos A

    2011-05-01

    The effect of ivermectin excreted in faeces of cattle treated in late winter on the arthropods and the degradation of faeces on pasture were evaluated. Four calves of similar age and weight were allocated to two groups, one group was treated subcutaneously with ivermectin and the other group remained as untreated control. From faeces collected from both groups at 3, 7, 14, 21 and 28 days post-treatment (dpt), three faecal pats of 1 kg each were made and deposited on a mixed paddock. One quarter of each faecal pat was removed at 10, 20, 30 and 60 days postdeposition (dpd) to determine the concentration of ivermectin, the organic matter content, and to collect colonising dung arthropods. Concentrations at days 3 and 7 pt were significantly higher than at the other dpt (p<0.05). The highest ivermectin concentrations were found in samples from 3 dpt (p<0.05). The organic matter percentage was not significantly different between treatments. An edaphic fauna characterised the colonisation of the faeces by organisms. Although arthropods' abundance differences were not significant except for the 28 dpt at 30 dpd (p<0.0003), fewer organisms were collected from the ivermectin group at all times.

  9. Effects of magnesium intake deficiency on bone metabolism and bone tissue around osseointegrated implants.

    PubMed

    Belluci, Marina Montosa; Giro, Gabriela; del Barrio, Ricardo Andrés Landazuri; Pereira, Rosa Maria Rodrigues; Marcantonio, Elcio; Orrico, Silvana Regina Perez

    2011-07-01

    This study evaluated the effect of magnesium dietary deficiency on bone metabolism and bone tissue around implants with established osseointegration. For this, 30 rats received an implant in the right tibial metaphysis. After 60 days for healing of the implants, the animals were divided into groups according to the diet received. Control group (CTL) received a standard diet with adequate magnesium content, while test group (Mg) received the same diet except for a 90% reduction of magnesium. The animals were sacrificed after 90 days for evaluation of calcium, magnesium, osteocalcin and parathyroid hormone (PTH) serum levels and the deoxypyridinoline (DPD) level in the urine. The effect of magnesium deficiency on skeletal bone tissue was evaluated by densitometry of the lumbar vertebrae, while the effect of bone tissue around titanium implants was evaluated by radiographic measurement of cortical bone thickness and bone density. The effect on biomechanical characteristics was verified by implant removal torque testing. Magnesium dietary deficiency resulted in a decrease of the magnesium serum level and an increase of PTH and DPD levels (P ≤ 0.05). The Mg group also presented a loss of systemic bone mass, decreased cortical bone thickness and lower values of removal torque of the implants (P ≤ 0.01). The present study concluded that magnesium-deficient diet had a negative influence on bone metabolism as well as on the bone tissue around the implants. © 2010 John Wiley & Sons A/S.

  10. Counterintuitive cooperative endocytosis of like-charged nanoparticles in cellular internalization: computer simulation and experiment

    NASA Astrophysics Data System (ADS)

    Li, Ye; Yuan, Bing; Yang, Kai; Zhang, Xianren; Yan, Bing; Cao, Dapeng

    2017-02-01

    The nanoparticles (NPs) functionalized with charged ligands are of particular significance due to their potential drug/gene delivery and biomedical applications. However, the molecular mechanism of endocytosis of the charged NPs by cells, especially the effect of the NP-NP and NP-biomembrane interactions on the internalization pathways is still poorly understood. In this work, we systematically investigate the internalization behaviors of the positively charged NPs by combining experiment technology and dissipative particle dynamics (DPD) simulation. We experimentally find an interesting but highly counterintuitive phenomenon, i.e. the multiple positively charged NPs prefer to enter cells cooperatively although the like-charged NPs have obvious electrostatic repulsion. Furthermore, we adopt the DPD simulation to confirm the experimental findings, and reveal that the mechanism of the cooperative endocytosis between like-charged NPs is definitely caused by the interplay of particle size, the charged ligand density on particle surface and local concentration of NPs. Importantly, we not only observe the normal cooperative endocytosis of like-charged NPs in cell biomembrane like neutral NP case, but also predict the ‘bud’ cooperative endocytosis of like-charged NPs which is absence in the neutral NP case. The results indicate that electrostatic repulsion between the positively charged nanoparticles plays an important role in the ‘bud’ cooperative endocytosis of like-charged NPs.

  11. Coulometric assay of deuterium loading levels in palladium electrodes. Technical report

    SciTech Connect

    Lawson, D.R.; Tierney, M.J.; Cheng, I.F.; Van Dyke, L.S.; Espenscheid, M.W.

    1990-12-06

    We report in this paper measurements of hydrogen (H) and deuterium (D) loading stoichiometries in Pd electrodes. We accomplished these analyses using an electrochemical method developed for in situ determination of palladium deuteride stoichiometries. The electrochemical method quantifies the amount of deuterium incorporated into the metal lattice by collecting the charge released during the potential controlled discharge of deuterium loaded Pd electrodes. In addition, ex situ gravimetric analyses were used to confirm electrochemically measured D/Pd atom ratios. Gravimetric analyses were also used in cases where the diameter of the Pd electrode precluded the relatively slow diffusion-limited electrochemical discharge method. A variety of electrolytic factors were studied to determine what conditions, if any, promote the greatest absorption of deuterium into the Pd lattice. We observed loading values of 0.73 + or - 0.02 deuterium atoms per Pd lattice atom under all the electrolytic conditions studied in LiOD and D2SO4 solutions. As found in previous studies, H/Pd values were approximately 10% higher than D/Pd values.

  12. Cross-linguistic comparison of speech errors produced by English- and French-speaking preschool-age children with developmental phonological disorders.

    PubMed

    Brosseau-Lapré, Françoise; Rvachew, Susan

    2014-04-01

    Twenty-four French-speaking children with developmental phonological disorders (DPD) were matched on percentage of consonants correct (PCC)-conversation, age, and receptive vocabulary measures to English-speaking children with DPD in order to describe how speech errors are manifested differently in these two languages. The participants' productions of consonants on a single-word test of articulation were compared in terms of feature-match ratios for the production of target consonants, and type of errors produced. Results revealed that the French-speaking children had significantly lower match ratios for the major sound class features [+ consonantal] and [+ sonorant]. The French-speaking children also obtained significantly lower match ratios for [+ voice]. The most frequent type of errors produced by the French-speaking children was syllable structure errors, followed by segment errors, and a few distortion errors. On the other hand, the English-speaking children made more segment than syllable structure and distortion errors. The results of the study highlight the need to use test instruments with French-speaking children that reflect the phonological characteristics of French at multiple levels of the phonological hierarchy.

  13. A polymer microgel at a liquid-liquid interface: theory vs. computer simulations.

    PubMed

    Rumyantsev, Artem M; Gumerov, Rustam A; Potemkin, Igor I

    2016-08-10

    We propose a mean-field theory and dissipative particle dynamics (DPD) simulations of swelling and collapse of a polymer microgel adsorbed at the interface of two immiscible liquids (A and B). The microgel reveals surface activity and lowers A-B interfacial tension. Attempting to occupy as large an interfacial area as possible, the microgel undergoes anisotropic deformation and adopts a flattened shape. Spreading over the interface is restricted by polymer subchain elasticity. The equilibrium shape of the microgel at the interface depends on its size. Small microgels are shown to be more oblate than the larger microgels. Increasing microgel cross-link density results in stronger reduction of the surface tension and weaker flattening. As the degree of immiscibility of A and B liquids increases, the microgel volume changes in a non-monotonous fashion: the microgel contraction at moderate immiscibility of A and B liquids is followed by its swelling at high incompatibility of the liquids. The segregation regime of the liquids within and outside the microgel is different. Being segregated outside the microgel, the liquids can be fully (homogeneously) mixed or weakly segregated within it. The density profiles of the liquids and the polymer were plotted under different conditions. The theoretical and the DPD simulation results are in good agreement. We hope that our findings will be useful for the design of stimuli responsive emulsions, which are stabilized by the microgel particles, as well as for their practical applications, for instance, in biocatalysis.

  14. The Preemptive Stocker Dispatching Rule of Automatic Material Handling System in 300 mm Semiconductor Manufacturing Factories

    NASA Astrophysics Data System (ADS)

    Wang, C. N.; Lin, H. S.; Hsu, H. P.; Wang, Yen-Hui; Chang, Y. P.

    2016-04-01

    The integrated circuit (IC) manufacturing industry is one of the biggest output industries in this century. The 300mm wafer fabs is the major fab size of this industry. The automatic material handling system (AMHS) has become one of the most concerned issues among semiconductor manufacturers. The major lot delivery of 300mm fabs is used overhead hoist transport (OHT). The traffic jams are happened frequently due to the wide variety of products and big amount of OHTs moving in the fabs. The purpose of this study is to enhance the delivery performance of automatic material handling and reduce the delay and waiting time of product transportation for both hot lots and normal lots. Therefore, this study proposes an effective OHT dispatching rule: preemptive stocker dispatching (PSD). Simulation experiments are conducted and one of the best differentiated preemptive rule, differentiated preemptive dispatching (DPD), is used for comparison. Compared with DPD, The results indicated that PSD rule can reduce average variable delivery time of normal lots by 13.15%, decreasing average variable delivery time of hot lots by 17.67%. Thus, the PSD rule can effectively reduce the delivery time and enhance productivity in 300 mm wafer fabs.

  15. Development of a stability-indicating HPLC method of etifoxine with characterization of degradation products by LC-MS/TOF, 1H and 13C NMR.

    PubMed

    Djabrouhou, Nadia; Guermouche, Moulay-Hassane

    2014-11-01

    This paper describes a new LC-MS/TOF method for the degradation products determination when Etifoxine (ETI) is submitted to different stress conditions. Chromatography is performed by using Kromasil C18 column (250mm×4.6mm, 5μm particle size). The selected mobile phase consists of formate buffer 0.02M, pH 3 and methanol (70/30, v/v). ETI is submitted to oxidative, acidic, basic, hydrolytic, thermal and UV light degradations. Detection is made at 254nm by photodiode array detector and mass spectrometry. A number of degradation products (DPs) called DPA, DPB, DPC and DPD are found depending on the stress; DPA with heat, DPA and DPB in acidic media or under UV-light; DPA, DPB and DPC under basic stress; DPA, DPB, DPC and DPD with oxidation. LC-MS/TOF is used to characterize the four DPs of ETI resulting from different stress conditions. (1)H and (13)C NMR are used to confirm the DP structures. The ETI fragmentation pathway is proposed. The method is validated with reference to International Conference on Harmonization guidelines and ETI are selectively determined in presence of its DPs, demonstrating its stability-indicating nature. Finally, for the validation step, specificity, linearity, accuracy and precision are determined for ETI and its DPs.

  16. Multiscale study of the self-organized gradient effect of novel hole injection material PEDOT:PSS:PFI

    NASA Astrophysics Data System (ADS)

    Huang, Min

    2016-09-01

    Conducting polymers, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been widely used as the hole injection layer (HIL) in many applications. However, in OLEDs the commonly used PEDOT:PSS has been found to have serious problems due to its inefficient holeinjection, inefficient electron-blocking, and substantial quenching of excitons close to the PEDOT:PSS. In the literature, tetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octene-sulfonic acid copolymer, one of perfluorinated ionomers (PFI), was introduced into the PEDOT:PSS layer to develop a gradient work function (WF) by self-organization of the PFI. In this contribution, the self-organized gradient effect of this novel PEDOT:PSS:PFI layer were studied using multiscale analysis and dissipative particle dynamics (DPD) simulation. The DPD inter particle repulsion parameters and intramolecular bonding parameters were obtained by reverse mapping of a series of molecular dynamics simulations similar to that used in the earlier contributions. The calculated Flory-Huggins parameters indicated that the Nafion portion of the copolymer attracts PSS while the entire PFI molecule repulses PEDOT, which results in a PFI rich interface and a vertical gradient concentration distribution of PEDOT along the vertical direction of the film layer.

  17. Adaptive resolution simulations coupling atomistic water to dissipative particle dynamics.

    PubMed

    Zavadlav, Julija; Praprotnik, Matej

    2017-09-21

    Multiscale methods are the most efficient way to address the interlinked spatiotemporal scales encountered in soft matter and molecular liquids. In the literature reported hybrid approaches span from quantum to atomistic, coarse-grained, and continuum length scales. In this article, we present the hybrid coupling of the molecular dynamics (MD) and dissipative particle dynamics (DPD) methods, bridging the micro- and mesoscopic descriptions. The interfacing is performed within the adaptive resolution scheme (AdResS), which is a linear momentum conserving coupling technique. Our methodology is hence suitable to simulate fluids on the micro/mesoscopic scale, where hydrodynamics plays an important role. The presented approach is showcased for water at ambient conditions. The supramolecular coupling is enabled by a recently developed clustering algorithm SWINGER that assembles, disassembles, and reassembles clusters as needed during the course of the simulation. This allows for a seamless coupling between standard atomistic MD and DPD models. The developed framework can be readily applied to various applications in the fields of materials and life sciences, e.g., simulations of phospholipids and polymer melts, or to study the red blood cells behavior in normal and disease states.

  18. Flow-induced translocation of polymers through a fluidic channel: a dissipative particle dynamics simulation study.

    PubMed

    Guo, Jiayi; Li, Xuejin; Liu, Yuan; Liang, Haojun

    2011-04-07

    The dynamics of flow-induced translocation of polymers through a fluidic channel has been studied by dissipative particle dynamics (DPD) approach. Unlike implicit solvent models, the many-body energetic and hydrodynamic interactions are preserved naturally by incorporating explicit solvent particles in this approach. The no-slip wall boundary and the adaptive boundary conditions have been implemented in the modified DPD approach to model the hydrodynamic flow within a specific wall structure of fluidic channel and control the particles' density fluctuations. The results show that the average translocation time versus polymer chain length satisfies a power-law scaling of τ ∼N(1.152). The conformational changes and translocation dynamics of polymers through the fluidic channel have also been investigated in our simulations, and two different translocation processes, i.e., the single-file and double-folded translocation events, have been observed in detail. These findings may be helpful in understanding the conformational and dynamic behaviors of such polymer and/or DNA molecules during the translocation processes.

  19. Dissipative particle dynamics modeling of blood flow in arterial bifurcations

    NASA Astrophysics Data System (ADS)

    Li, Xuejin; Lykov, Kirill; Pivkin, Igor V.; Karniadakis, George Em

    2013-11-01

    The motion of a suspension of red blood cells (RBCs) flowing in bifurcations is investigated using both low-dimensional RBC (LD-RBC) and multiscale RBC (MS-RBC) models based on dissipative particle dynamics (DPD). The blood flow is first simulated in a symmetric geometry between the diverging and converging channels to satisfy the periodic flow assumption along the flow direction. The results show that the flowrate ratio of the daughter channels and the feed hematocrit level has considerable influence on blood-plasma separation. We also propose a new method to model the inflow and outflow boundaries for the blood flow simulations: the inflow at the inlet is duplicated from a fully developed flow generated by DPD fluid with periodic boundary conditions; the outflow in two adjacent regions near the outlet is controlled by adaptive forces to keep the flowrate and velocity gradient equal, while the particles leaving the microfluidic channel at the outlet at each time step are removed from the system. The simulation results of the developing flow match analytical solutions from continuum theory. Plasma skimming and the all-or-nothing phenomenon of RBCs in bifurcation have been investigated in the simulations. The simulation results are consistent with previous experimental results and theoretical predictions. This work is supported by the NIH Grant R01HL094270.

  20. Dispersion/Aggregation of polymer grafted nanorods in a polymer matrix studied by Dissipative Particle Dynamics

    NASA Astrophysics Data System (ADS)

    Maia, Joao; Khani, Shaghayegh

    2015-03-01

    Nanorods are incorporated into polymer matrices for fabricating composite materials with enhanced physical and mechanical properties.The final macroscopic properties of the composites are directly related to the dispersion and organization of the nanoparticles in the matrix. For instance, a significant improvement in the mechanical properties of the nanorod-polymer composites is observed upon formation of a percolating network. One way of controlling the assembly of nanorods in the polymer medium is adjusting the chemical interactions which is done through grafting polymer chains on the surface of the rods. The recent developments in the computational techniques have paved the road for further understanding of the controlled dispersion and aggregation of nanorods in polymer matrices. In this study, Dissipative Particle Dynamics (DPD) is employed in order to investigate the effect of enthalpic and entopic variables on the phase behavior of the abovementioned nanocomposites. In DPD, the interaction parameter between the components of the systems can be mapped onto the Flory-Huggins χ-parameter via well-known Groot-Warren expression. This works studies the effect of the enthalpic and entropic variables on phase transitions. The main goal is to provide a phase diagram than can be used to guide the experiments in designing new materials.

  1. Simulation and experimental study of rheological properties of CeO2-water nanofluid

    NASA Astrophysics Data System (ADS)

    Loya, Adil; Stair, Jacqueline L.; Ren, Guogang

    2015-10-01

    Metal oxide nanoparticles offer great merits over controlling rheological, thermal, chemical and physical properties of solutions. The effectiveness of a nanoparticle to modify the properties of a fluid depends on its diffusive properties with respect to the fluid. In this study, rheological properties of aqueous fluids (i.e. water) were enhanced with the addition of CeO2 nanoparticles. This study was characterized by the outcomes of simulation and experimental results of nanofluids. The movement of nanoparticles in the fluidic media was simulated by a large-scale molecular thermal dynamic program (i.e. LAMMPS). The COMPASS force field was employed with smoothed particle hydrodynamic potential (SPH) and discrete particle dynamics potential (DPD). However, this study develops the understanding of how the rheological properties are affected due to the addition of nanoparticles in a fluid and the way DPD and SPH can be used for accurately estimating the rheological properties with Brownian effect. The rheological results of the simulation were confirmed by the convergence of the stress autocorrelation function, whereas experimental properties were measured using a rheometer. These rheological values of simulation were obtained and agreed within 5 % of the experimental values; they were identified and treated with a number of iterations and experimental tests. The results of the experiment and simulation show that 10 % CeO2 nanoparticles dispersion in water has a viscosity of 2.0-3.3 mPas.

  2. Improvement of charged particles transport across a transverse magnetic filter field by electrostatic trapping of magnetized electrons

    SciTech Connect

    Das, B. K. Hazarika, P.; Chakraborty, M.; Bandyopadhyay, M.

    2014-07-15

    A study on the transport of charged particles across a magnetic filter field has been carried out in a double plasma device (DPD) and presented in this manuscript. The DPD is virtually divided into two parts viz. source and target regions by a transverse magnetic field (TMF) which is constructed by inserting strontium ferrite magnets into two stainless steel rectangular tubes. Plasma electrons are magnetized but ions are unmagnetized inside the TMF region. Negative voltages are applied to the TMF tubes in order to reduce the loss of electrons towards them. Plasma is produced in the source region by filament discharge method and allowed to flow towards the target region through this negatively biased TMF. It is observed that in the target region, plasma density can be increased and electron temperature decreased with the help of negatively biased TMF. This observation is beneficial for negative ion source development. Plasma diffusion across the negatively biased TMF follows Bohm or anomalous diffusion process when negative bias voltage is very less. At higher negative bias, diffusion coefficient starts deviating from the Bohm diffusion value, associated with enhanced plasma flow in the target region.

  3. Experimental observations and dissipative particle dynamic simulations on microstructures of pH-sensitive polymer containing amorphous solid dispersions.

    PubMed

    Sun, Mengchi; Li, Bingyu; Li, Yanchun; Liu, Yangdan; Liu, Qi; Jiang, Hailun; He, Zhonggui; Zhao, Yongshan; Sun, Jin

    2017-01-30

    Amorphous solid dispersion (ASD) technique is an effective strategy to increase the dissolution rate of poorly soluble drugs. However, it is inherently unstable, and the molecular basis for achieving kinetic stability is not well understood. In this study, lacidipine-Eudragit_E_100 solid dispersions with 20% drug loading were prepared using the solvent evaporation. Dissolution tested showed that ASD had a significantly high rate, which was dependent on the pH of the medium. Based on time-dependent measurement of supersaturation and particle size, inhibition of crystal growth by Eudragit_E_100 differed at pH 1.2 and 6.8 to a great extent. Dissipative particle dynamic (DPD) simulation revealed that at pH 1.2, the swollen microstructures of the particles were associated with rapid drug release. At pH 6.8, a compacted microstructure of small amorphous particle-aggregated large particles was associated with slow dissolution. The DPD simulation provides insight into the structural basis for experimental observations, and thus is a useful tool to investigate the microstructures of ASD.

  4. A Novel Pickup Head Design for DVD-Multi System

    NASA Astrophysics Data System (ADS)

    Huang, Der-Ray; Ju, Jau-Jiu; Wei, Li-Ding; Chang, Chi-Lone; Shih, Hsi-Fu; Yang, Tzu-Ping

    2001-02-01

    This paper introduces a novel holographic optical element (HOE) pattern design to generate focusing and tracking signal for using in digital versatile disc DVD-multi pickup heads. The digital verstile disk (DVD) multi drive will be able to read disks written in the DVD-ROM, DVD-video, DVD-audio, DVD-R/W, and DVD-R formats. DVD multi drive will also be able to write disks in the DVD-RAM and DVD-RW/R formats. The HOE design provides the focusing error signal and both differential phase detection (DPD) and pushpull tracking signals for DVD-ROM disks and rewritable land-groove disks. The HOE pattern is divided into two main regions. The inner region is for focus detection and the outer region is for DPD and Pushpull tracking detection. In this study, a rotary actuator is used to reduce the tilt angle of the objective lens in the DVD-multi pickup head. The finite element method of the actuator is studied to analyze the resonance of the structure and the magnetic field of the voice coil motor.

  5. A novel action of histone deacetylase inhibitors in a protein aggresome disease model.

    PubMed

    Corcoran, Lisa J; Mitchison, Timothy J; Liu, Qing

    2004-03-23

    Protein inclusions are associated with a number of neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). Whether protein aggregates are toxic or beneficial to cells is not known. In ALS animal models, mutant SOD1 forms aggresome-like structures in motor neurons and astrocytes. To better understand the role of protein aggregation in the progression of disease etiology, we performed a screen for small molecules that disrupt aggresome formation in cultured cells. After screening 20,000 compounds, we obtained two groups of compounds that specifically prevented aggresome formation. One group consists mainly of cardiac glycosides and will be the subject of another study. The second group contains two compounds: one is a known histone deacetylase (HDAC) inhibitor, Scriptaid, and the other is a Flavin analog, DPD. Cells treated with these molecules still contained microaggregates, but these microaggregates were not transported to microtubule organizing centers (MTOCs). The defect in transport was linked to modulation of the dynein/dynactin machinery as treatment with Scriptaid or DPD reversed mSOD-induced insolubilization of the dynactin subunits P50 dynamitin and P150(glued). Our findings suggest a connection between HDAC activity and aggresome formation and also lay the groundwork for a direct test of the role of aggresome formation in ALS etiology.

  6. Programmable tactile pattern presentations operational under MRI to investigate neural mechanisms of tactile shape discrimination.

    PubMed

    Yang, Jiajia; Wu, Jinglong; He, Jiping

    2011-09-30

    We have developed a novel tactile presentation system for assessing and training cognitive function on tactile senses. The device is operational in magnetic resonance imaging (MRI) environment and capable of investigating the underlying neural mechanisms of tactile pattern discrimination. The primary components of the system include a finger movement control unit (FCU), a disk for multiple tactile pattern delivery (DPD), and a force-sensing unit (FSU). An ultrasonic motor rotates the DPD to deliver different tactile patterns for cognitive sensitivity test. We evaluated the operational reliability and the performance of the system in a MRI environment. The results showed that the system performance was not affected by the magnetic field, nor did the system operation interfere with the magnetic field either. The results from the two functional MRI experiments also indicated that the brain activation can be reliably detected with the present system. Furthermore, a tactile pattern discrimination experiment was conducted using the system to investigate cognitive characteristics of shape discrimination under active and passive touch conditions. We found that the mean accuracy of discrimination under active touch was significantly higher than that under passive touch. The high accuracy and magnetic field compatibility of the device suggest that the device provides a powerful means of investigating the neural mechanisms of perception and cognitive function for touch discrimination.

  7. [A case of advanced colon cancer with metastases to both para-aortic lymph nodes and cervical vertebrae effectively treated by TS-1 therapy].

    PubMed

    Ohnuma, Masaru; Uchiyama, Tetsuyuki; Abe, Tomoya; Nakagawa, Kei; Kamiyama, Yasuhiko; Watanabe, Mika; Moriya, Takuya; Ise, Hideo

    2006-04-01

    The patient was a 68-year-old woman who had cecal cancer with para-aortic lymph node metastases. Ileocecal resection was performed palliatively. Since metastasis to cervical vertebrae was detected after the operation, she received radiation therapy of 14 Gy to improve neck pain. Chemotherapy with TS-1 (80 mg/day) was started on an outpatient basis (4 weeks administration followed by a 2-week drug-free period). After 4 courses of this chemotherapy, metastases to both para-aortic lymph nodes and cervical vertebrae were remarkably reduced on CT and PET. Throughout the period of treatment, there was no adverse effect and this treatment has been maintained. In conclusion, this case seems significant from the viewpoint of achieving a partial response to TS-1 and maintaining a high quality of life. Moreover,we identified the presence of TS and DPD using an immunohistochemical staining technique. The primary tumor was positive for DPD stain test and negative for TS stain test. It was suggested that this cancer especially would respond to TS-1 chemotherapy.

  8. Elevation of circulating serotonin improves calcium dynamics in the peripartum dairy cow.

    PubMed

    Weaver, Samantha R; Prichard, Austin P; Endres, Elizabeth L; Newhouse, Stefanie A; Peters, Tonia L; Crump, Peter M; Akins, Matthew S; Crenshaw, Thomas D; Bruckmaier, Rupert M; Hernandez, Laura L

    2016-07-01

    Hypocalcemia is a metabolic disorder that affects dairy cows during the transition from pregnancy to lactation. Twelve multiparous Holstein cows and twelve multiparous Jersey cows were intravenously infused daily for approximately 7 days prepartum with either saline or 1.0mg/kg bodyweight of the immediate precursor to serotonin synthesis, 5hydroxy-l-tryptophan (5-HTP). On infusion days, blood was collected before, after, and at 2, 4, and 8h postinfusion. Blood and urine were collected daily before the infusion period, for 14 days postpartum and on day 30 postpartum. Milk was collected daily during the postpartum period. Feed intake and milk yield were unaffected by 5-HTP infusion postpartum. Cows infused with 5-HTP had elevated circulating serotonin concentrations prepartum. Infusion with 5-HTP induced a transient hypocalcemia in Jersey cows prepartum, but not in any other treatment. Holstein cows infused with saline had the highest milk calcium on the day of and day after parturition. Postpartum, circulating total calcium tended to be elevated, and urine deoxypyridinoline (DPD) concentrations were elevated in Holstein cows infused with 5-HTP. Overall, Jerseys had higher urine DPD concentrations postpartum when compared with Holsteins. Taken together, these data warrant further investigation of the potential therapeutic benefit of 5-HTP administration prepartum for prevention of hypocalcemia. Further research should focus on delineation of mechanisms associated with 5-HTP infusion that control calcium homeostasis during the peripartum period in Holstein and Jersey cows. © 2016 Society for Endocrinology.

  9. 5-Fluorouracil catabolism to 5-fluoro-5,6-dihydrouracil is reduced by acute liver impairment in mice

    SciTech Connect

    Innocenti, Federico; Danesi, Romano; Bocci, Guido; Natale, Gianfranco . E-mail: gianfranco.natale@anist.med.unipi.it; Del Tacca, Mario

    2005-03-01

    This study investigated the effect of acute liver damage on the inactivation of 5-fluorouracil (5-FU) to its main catabolite 5-fluoro-5,6-dihydrouracil (5-FUH{sub 2}) in mice. Plasma pharmacokinetics of 5-FU and 5-FUH{sub 2} in mice receiving 5-FU (10, 30, and 90 mg/kg) were compared to those in mice pretreated with carbon tetrachloride and receiving the same 5-FU doses. Carbon tetrachloride-induced hepatic damage was histopathologically examined under light microscopy and serum transaminases and dihydropyrimidine dehydrogenase activities were also measured. Liver histopathology and elevated aminotransferase activity levels confirmed the presence of liver damage. 5-FU C{sub max} and AUC both increased up to 71% in mice with liver damage. This was reflected by decreased 5-FUH{sub 2} production, since 5-FUH{sub 2} C{sub max} and AUC levels decreased up to 47% and 61%, respectively. Metabolic ratios between 5-FUH{sub 2} and 5-FU AUCs were considerably decreased as well, further suggesting that liver damage caused a reduction in 5-FU catabolism. DPD activity was not altered in damaged livers. The present results indicate that 5-FU disposition in mice could be profoundly altered in the presence of severe liver impairment, potentially leading to enhanced anabolic activation of 5-FU. This effect seems to be ascribed to a reduction of viable hepatocytes, rather than to an inactivation of DPD activity.

  10. pH-sensitive drug loading/releasing in amphiphilic copolymer PAE-PEG: integrating molecular dynamics and dissipative particle dynamics simulations.

    PubMed

    Luo, Zhonglin; Jiang, Jianwen

    2012-08-20

    Molecular dynamics (MD) and dissipative particle dynamics (DPD) simulations are integrated to investigate the loading/releasing of anti-cancer drug camptothecin (CPT) in pH-sensitive amphiphilic copolymer, composed of hydrophobic poly(β-amino ester) (PAE) and hydrophilic methyl ether-capped poly(ethylene glycol) (PEG). MD simulation is used to estimate the Flory-Huggins interaction parameters and miscibility of binary components. On this basis, DPD simulation is applied to examine the micellization of PAE-PEG, CPT loading in PAE-PEG, and CPT releasing in PAEH-PEG. With increasing concentration, PAE-PEG forms spherical then disk-like micelles and finally vesicles, as a competitive counterbalance of free energies for the formation of shell, interface and core. CPT loading in PAE-PEG micelles/vesicles is governed by adsorption-growth-micellization mechanism, and CPT is loaded into both hydrophobic core and interface of hydrophobic core/hydrophilic shell. The predicted loading efficiency is close to experimental value. Similar to literature reports, the loading of high concentration of CPT is observed to cause morphology transition from micelles to vesicles. Upon protonation, CPT is released from micelles/vesicles by swelling-demicellization-releasing mechanism. This multi-scale simulation study provides microscopic insight into the mechanisms of drug loading and releasing, and might be useful for the design of new materials for high-efficacy drug delivery.

  11. The aggregation and diffusion of asphaltenes studied by GPU-accelerated dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Wang, Sibo; Xu, Junbo; Wen, Hao

    2014-12-01

    The heavy crude oil consists of thousands of compounds and much of them have large molecular weights and complex structures. Studying the aggregation and diffusion behavior of asphaltenes can facilitate the understanding of the heavy crude oil. In previous studies, the fused aromatic rings were treated as rigid bodies so that dissipative particle dynamics (DPD) integrated with the quaternion method can be used to study asphaltene systems. In this work, DPD integrated with the quaternion method is implemented on graphics processing units (GPUs). Compared with the serial program, tens of times speedup can be achieved when simulations performed on a single GPU. Using multiple GPUs can provide faster computation speed and more storage space for simulations of significant large systems. By using large systems, simulations of the asphaltene-toluene system at extremely dilute concentrations can be performed. The determined diffusion coefficients of asphaltenes are similar to that in experimental studies. At last, the aggregation behavior of asphaltenes in heptane was investigated, and the simulation results agreed with the modified Yen model. Monomers, nanoaggregates and clusters were observed from the simulations at different concentrations.

  12. Evaluation of approaches to quantify total residual oxidants in ballast water management systems employing chlorine for disinfection.

    PubMed

    Zimmer-Faust, Amity G; Ambrose, Richard F; Tamburri, Mario N

    2014-01-01

    With the maturation and certification of several ballast water management systems that employ chlorine as biocide to prevent the spread of invasive species, there is a clear need for accurate and reliable total residual oxidants (TRO) technology to monitor treatment dose and assure the environmental safety of treated water discharged from ships. In this study, instruments used to measure TRO in wastewater and drinking water applications were evaluated for their performance in scenarios mimicking a ballast water treatment application (e.g., diverse hold times, temperatures, and salinities). Parameters chosen for testing these technologies in the past do not reflect conditions expected during ballast water treatment. Salinity, temperature, and oxidant concentration all influenced the response of amperometric sensors. Oxidation reduction potential (ORP) sensors performed more consistently than amperometric sensors under different conditions but it may be difficult to correlate ORP and TRO measurements for the multitude of biogeochemical conditions found naturally in ballast water. N,N-diethyl-p-phenylenediamine (DPD) analyzers and amperometric sensors were also tested under intermittent sampling conditions mimicking a ballasting scenario, with cyclical dosage and discharge operations. When sampling was intermittent, amperometric sensors required excessive response and conditioning times, whereas DPD analyzers provided reasonable estimates of TRO under the ballasting scenario.

  13. Volatile disinfection by-product analysis from chlorinated indoor swimming pools.

    PubMed

    Weaver, William A; Li, Jing; Wen, Yuli; Johnston, Jessica; Blatchley, Michael R; Blatchley, Ernest R

    2009-07-01

    Chlorination of indoor swimming pools is practiced for disinfection and oxidation of reduced compounds that are introduced to water by swimmers. However, there is growing concern associated with formation for chlorinated disinfection by-products (DBPs) in these settings. Volatile DBPs are of particular concern because they may promote respiratory ailments and other adverse health effects among swimmers and patrons of indoor pool facilities. To examine the scope of this issue, water samples were collected from 11 pools over a 6month period and analyzed for f