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Sample records for aggregated transfer factors

  1. Aggregated Transfer Factors For Small Mammals Collected From the Exposed Sediments Of A 137 Cs Contaminated Reservoir

    SciTech Connect

    Paller, Michael H.; Jannika, G. Timothy; Wike, Lynn D

    2005-10-04

    {sup 137}Cs transfer factors were computed for small mammals collected from the dried sediment areas of a partially drained, contaminated reservoir. Soil {sup 137}Cs concentrations were heterogeneous on small and large spatial scales, with a geometric mean of 253.1 Bq/kg dry weight. About 50% of the variance in cotton rat Sigmodon hispidus tissue {sup 137}Cs levels was explained by variation in soil {sup 137}Cs levels. Soil to animal transfer factors (whole body dry weight) averaged 6.0 for cotton rats and 1.2 for cotton mice Peromyscus gossypinus. These values are similar to {sup 137}Cs transfer factors for herbivorous, homeothermic animals from other contaminated ecosystems. Site-specific transfer factors can significantly affect the estimation of dose. In the RESRAD-BIOTA dose model, the default transfer factor for {sup 137}Cs in terrestrial animals is 110 resulting in an estimate of radiation dose to terrestrial biota that is 16 times more than the dose calculated with the actual measured transfer factor.

  2. Retrospective determination of 137Cs specific activity distribution in spruce bark and bark aggregated transfer factor in forests on the scale of the Czech Republic ten years after the Chernobyl accident.

    PubMed

    Suchara, I; Rulík, P; Hůlka, J; Pilátová, H

    2011-04-15

    The (137)Cs specific activities (mean 32Bq kg(-1)) were determined in spruce bark samples that had been collected at 192 sampling plots throughout the Czech Republic in 1995, and were related to the sampling year. The (137)Cs specific activities in spruce bark correlated significantly with the (137)Cs depositions in areas affected by different precipitation sums operating at the time of the Chernobyl fallout in 1986. The ratio of the (137)Cs specific activities in bark and of the (137)Cs deposition levels yielded bark aggregated transfer factor T(ag) about 10.5×10(-3)m(-2)kg(-1). Taking into account the residual specific activities of (137)Cs in bark 20Bq kg(-1) and the available pre-Chernobyl data on the (137)Cs deposition loads on the soil surface in the Czech Republic, the real aggregated transfer factor after and before the Chernobyl fallout proved to be T*(ag)=3.3×10(-3)m(-2)kg(-1) and T**(ag)=4.0×10(-3)m(-2)kg(-1), respectively. The aggregated transfer factors T*(ag) for (137)Cs and spruce bark did not differ significantly in areas unequally affected by the (137)Cs fallout in the Czech Republic in 1986, and the figures for these aggregated transfer factors were very similar to the mean bark T(ag) values published from the extensively affected areas near Chernobyl. The magnitude of the (137)Cs aggregated transfer factors for spruce bark for the pre-Chernobyl and post-Chernobyl period in the Czech Republic was also very similar. The variability in spruce bark acidity caused by the operation of local anthropogenic air pollution sources did not significantly influence the accumulation and retention of (137)Cs in spruce bark. Increasing elevation of the bark sampling plots had a significant effect on raising the remaining (137)Cs specific activities in bark in areas affected by precipitation at the time when the plumes crossed, because the sums of this precipitation increased with elevation (covariable). PMID:21377193

  3. Exciton Transfer in Carbon Nanotube Aggregates for Energy Harvesting Applications

    NASA Astrophysics Data System (ADS)

    Davoody, Amirhossein; Karimi, Farhad; Knezevic, Irena

    Carbon nanotubes (CNTs) are promising building blocks for organic photovoltaic devices, owing to their tunable band gap, mechanical and chemical stability. We study intertube excitonic energy transfer between pairs of CNTs with different orientations and band gaps. The optically bright and dark excitonic states in CNTs are calculated by solving the Bethe-Salpeter equation. We calculate the exciton transfer rates due to the direct and exchange Coulomb interactions, as well as the second-order phonon-assisted processes. We show the importance of phonons in calculating the transfer rates that match the measurements. In addition, we discuss the contribution of optically inactive excited states in the exciton transfer process, which is difficult to determine experimentally. Furthermore, we study the effects of sample inhomogeneity, impurities, and temperature on the exciton transfer rate. The inhomogeneity in the CNT sample dielectric function can increase the transfer rate by about a factor of two. We show that the exciton confinement by impurities has a detrimental effect on the transfer rate between pairs of similar CNTs. The exciton transfer rate increases monotonically with increasing temperature. Support by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-SC0008712.

  4. Implications of epidermal growth factor (EGF) induced egf receptor aggregation.

    PubMed Central

    Wofsy, C; Goldstein, B; Lund, K; Wiley, H S

    1992-01-01

    To investigate the role of receptor aggregation in EGF binding, we construct a mathematical model describing receptor dimerization (and higher levels of aggregation) that permits an analysis of the influence of receptor aggregation on ligand binding. We answer two questions: (a) Can Scatchard plots of EGF binding data be analyzed productively in terms of two noninteracting receptor populations with different affinities if EGF induced receptor aggregation occurs? No. If two affinities characterize aggregated and monomeric EGF receptors, we show that the Scatchard plot should have curvature characteristic of positively cooperative binding, the opposite of that observed. Thus, the interpretation that the high affinity population represents aggregated receptors and the low affinity population nonaggregated receptors is wrong. If the two populations are interpreted without reference to receptor aggregation, an important determinant of Scatchard plot shape is ignored. (b) Can a model for EGF receptor aggregation and EGF binding be consistent with the "negative curvature" (i.e., curvature characteristic of negatively cooperative binding) observed in most Scatchard plots of EGF binding data? Yes. In addition, the restrictions on the model parameters required to obtain negatively curved Scatchard plots provide new information about binding and aggregation. In particular, EGF binding to aggregated receptors must be negatively cooperative, i.e., binding to a receptor in a dimer (or higher oligomer) having one receptor already bound occurs with lower affinity than the initial binding event. A third question we consider is whether the model we present can be used to detect the presence of mechanisms other than receptor aggregation that are contributing to Scatchard plot curvature. For the membrane and cell binding data we analyzed, the best least squares fits of the model to each of the four data sets deviate systematically from the data, indicating that additional factors are

  5. Cellular factors modulating the mechanism of tau protein aggregation.

    PubMed

    Fontaine, Sarah N; Sabbagh, Jonathan J; Baker, Jeremy; Martinez-Licha, Carlos R; Darling, April; Dickey, Chad A

    2015-05-01

    Pathological accumulation of the microtubule-associated protein tau, in the form of neurofibrillary tangles, is a major hallmark of Alzheimer's disease, the most prevalent neurodegenerative condition worldwide. In addition to Alzheimer's disease, a number of neurodegenerative diseases, called tauopathies, are characterized by the accumulation of aggregated tau in a variety of brain regions. While tau normally plays an important role in stabilizing the microtubule network of the cytoskeleton, its dissociation from microtubules and eventual aggregation into pathological deposits is an area of intense focus for therapeutic development. Here we discuss the known cellular factors that affect tau aggregation, from post-translational modifications to molecular chaperones. PMID:25666877

  6. Cellular factors modulating the mechanism of tau protein aggregation

    PubMed Central

    Fontaine, Sarah N.; Sabbagh, Jonathan J.; Baker, Jeremy; Martinez-Licha, Carlos R.; Darling, April

    2015-01-01

    Pathological accumulation of the microtubule-associated protein tau, in the form of neurofibrillary tangles, is a major hallmark of Alzheimer’s disease, the most prevalent neurodegenerative condition worldwide. In addition to Alzheimer’s disease, a number of neurodegenerative diseases, called tauopathies, are characterized by the accumulation of aggregated tau in a variety of brain regions. While tau normally plays an important role in stabilizing the microtubule network of the cytoskeleton, its dissociation from microtubules and eventual aggregation into pathological deposits is an area of intense focus for therapeutic development. Here we discuss the known cellular factors that affect tau aggregation, from post-translational modifications to molecular chaperones. PMID:25666877

  7. Energy transfer in aggregates of bacteriochlorophyll c self-assembled with azulene derivatives.

    PubMed

    Matěnová, Martina; Lorelei Horhoiu, Viviana; Dang, Florian-Xuan; Pospíšil, Petr; Alster, Jan; Burda, Jaroslav V; Balaban, Teodor Silviu; Pšenčík, Jakub

    2014-08-21

    Bacteriochlorophyll (BChl) c is the main light-harvesting pigment of certain photosynthetic bacteria. It is found in the form of self-assembled aggregates in the so-called chlorosomes. Here we report the results of co-aggregation experiments of BChl c with azulene and its tailored derivatives. We have performed spectroscopic and quantum chemical characterization of the azulenes, followed by self-assembly experiments. The results show that only azulenes with sufficient hydrophobicity are able to induce aggregation of BChl c. Interestingly, only azulene derivatives possessing a conjugated phenyl ring were capable of efficient (∼50%) excitation energy transfer to BChl molecules. These aggregates represent an artificial light-harvesting complex with enhanced absorption between 220 and 350 nm compared to aggregates of pure BChl c. The results provide insight into the principles of self-assembly of BChl aggregates and suggest an important role of the π-π interactions in efficient energy transfer. PMID:24999619

  8. A Fluorescence Resonance Energy Transfer Assay For Monitoring α- Synclein Aggregation in a Caenorhabditis Elegans Model For Parkinson's Disease.

    PubMed

    Nagarajan, Archana; Bodhicharla, Rakesh; Winter, Jody; Anbalagan, Charumathi; Morgan, Kevin; Searle, Mark; Nazir, Aamir; Adenle, Ademola; Fineberg, April; Brady, Declan; Vere, Kelly; Richens, Jo; O'Shea, Paul; Bell, David; de-Pomerai, David

    2015-01-01

    The aggregation of α-synuclein (Syn or S) to form insoluble fibrils is important in the pathogenesis of Parkinson's disease, but key risk factors remain ill-defined. We have developed Fluorescence Resonance Energy Transfer (FRET)-based assays for α-synuclein aggregation, using Green Fluorescent Protein variants Cerulean (C) or Venus (V), fused to each other (CV, VC) or to human synuclein (SC, SV etc). Bacterially expressed proteins were purified to homogeneity, and C-terminal fusions SC and SV largely retained their ability to aggregate in vitro. FRET signals from mixtures of SC and SV were used to monitor aggregation. These fusion genes were linked to the C. elegans unc-54 myosin promoter to generate integrated transgenic strains. Increased FRET signals, indicative of S aggregation, were observed following treatment of unc-54::SC + unc-54::SV double transgenic worms with low concentrations of mercury or chlorpyrifos, or with RNAi against hsp-70 and hip-1. Opposite changes in Yellow Fluorescent Protein (YFP) fluorescence in an unc-54::SV strain (NL5901) are likely to reflect FRET from Yellow Fluorescent Protein to aggregates of Syn fusion protein. This could provide the basis for a high throughput screening assay, which could be used for studying the effects of toxic chemicals and environmental pollutants on the aggregation of proteins such as Syn in vivo. PMID:26295817

  9. Proton transfer in oxidized adenosine self-aggregates.

    PubMed

    Capobianco, Amedeo; Caruso, Tonino; Celentano, Maurizio; La Rocca, Mario Vincenzo; Peluso, Andrea

    2013-10-14

    The UV-vis and the IR spectra of derivativized adenosine in dichloromethane have been recorded during potentiostatic oxidation at an optically transparent thin layer electrode. Oxidized adenosine shows a broad Zundel like absorption extending from 2800 up to 3600 cm(-1), indicating that a proton transfer process is occurring. Theoretical computations predict that proton transfer is indeed favored in oxidized 1:1 self-association complexes and allow to assign all the observed transient spectroscopic signals. PMID:24116647

  10. Prion aggregates transfer through tunneling nanotubes in endocytic vesicles

    PubMed Central

    Zhu, Seng; Victoria, Guiliana Soraya; Marzo, Ludovica; Ghosh, Rupam; Zurzolo, Chiara

    2015-01-01

    Abstract Transmissible spongiform encephalopathies (TSEs) are a group of neurodegenerative diseases caused by the misfolding of the cellular prion protein to an infectious form PrPSc. The intercellular transfer of PrPSc is a question of immediate interest as the cell-to-cell movement of the infectious particle causes the inexorable propagation of disease. We have previously identified tunneling nanotubes (TNTs) as one mechanism by which PrPSc can move between cells. Here we investigate further the details of this mechanism and show that PrPSc travels within TNTs in endolysosomal vesicles. Additionally we show that prion infection of CAD cells increases both the number of TNTs and intercellular transfer of membranous vesicles, thereby possibly playing an active role in its own intercellular transfer via TNTs. PMID:25996400

  11. Excitation transfer pathways in excitonic aggregates revealed by the stochastic Schrödinger equation

    SciTech Connect

    Abramavicius, Vytautas Abramavicius, Darius

    2014-02-14

    We derive the stochastic Schrödinger equation for the system wave vector and use it to describe the excitation energy transfer dynamics in molecular aggregates. We suggest a quantum-measurement based method of estimating the excitation transfer time. Adequacy of the proposed approach is demonstrated by performing calculations on a model system. The theory is then applied to study the excitation transfer dynamics in a photosynthetic pigment-protein Fenna-Matthews-Olson (FMO) aggregate using both the Debye spectral density and the spectral density obtained from earlier molecular dynamics simulations containing strong vibrational high-frequency modes. The obtained results show that the excitation transfer times in the FMO system are affected by the presence of the vibrational modes; however, the transfer pathways remain the same.

  12. Proaggregant nuclear factor(s) trigger rapid formation of α-synuclein aggregates in apoptotic neurons.

    PubMed

    Jiang, Peizhou; Gan, Ming; Yen, Shu-Hui; Moussaud, Simon; McLean, Pamela J; Dickson, Dennis W

    2016-07-01

    Cell-to-cell transmission of α-synuclein (αS) aggregates has been proposed to be responsible for progressive αS pathology in Parkinson disease (PD) and related disorders, including dementia with Lewy bodies. In support of this concept, a growing body of in vitro and in vivo experimental evidence shows that exogenously introduced αS aggregates can spread into surrounding cells and trigger PD-like pathology. It remains to be determined what factor(s) lead to initiation of αS aggregation that is capable of seeding subsequent propagation. In this study we demonstrate that filamentous αS aggregates form in neurons in response to apoptosis induced by staurosporine or other toxins-6-hydroxy-dopamine and 1-methyl-4-phenylpyridinium (MPP+). Interaction between αS and proaggregant nuclear factor(s) is associated with disruption of nuclear envelope integrity. Knocking down a key nuclear envelop constituent protein, lamin B1, enhances αS aggregation. Moreover, in vitro and in vivo experimental models demonstrate that aggregates released upon cell breakdown can be taken up by surrounding cells. Accordingly, we suggest that at least some αS aggregation might be related to neuronal apoptosis or loss of nuclear membrane integrity, exposing cytosolic α-synuclein to proaggregant nuclear factors. These findings provide new clues to the pathogenesis of PD and related disorders that can lead to novel treatments of these disorders. Specifically, finding ways to limit the effects of apoptosis on αS aggregation, deposition, local uptake and subsequent propagation might significantly impact progression of disease. PMID:26839082

  13. Photoinduced Charge and Energy Transfer Processes in Molecular Aggregates

    SciTech Connect

    John F. Endicott

    2009-10-20

    This project involved the experimental probing of the electronic excited states generated by photoinduced (center-to-center) electron and energy transfer processes in several classes of transition metal donor/acceptor (D/A) complexes. Some of the general properties inferred from these studies should be useful in the design of new systems for energy conversion applications. Pursuit of the project goals has involved the determination of electron transfer efficiencies and the detailed study of variations in the electronic spectra of D/A complexes. This has resulted in the study of some very fundamental issues of photoinduced charge transfer and the identification of some of the constraints on its efficiency. The experimental studies of the competition between the degradative non-radiative unimolecular relaxation of transition metal excited states and their transfer of charge from these excited states to external acceptors have involved a range of techniques such as transient decay kinetics, photoacoustic calorimetry and transient or stationary state spectroscopy. The substrates synthesized for these studies were selected to provide model systems, or series of model systems to probe the validity of models of electronic excited states and their reactivity. The work during the last few years has focused largely, but not exclusively, on the use of emission spectral band shapes to probe the properties of charge transfer (CT) excited states. Bandshape variations are one of the very few approaches for systematically probing electronic excited states and good band shape resolution is necessary in order to gain information about the structural variations that correlate with excited state reactivity. Differences in molecular structure correlate with differences in chemical reactivity, and the variations in emission bandshapes are well known to relate to variations in the molecular structural differences between the excited and ground electronic states. However, it is has been

  14. Factors Affecting Transfer of Training in Thailand

    ERIC Educational Resources Information Center

    Yamnill, Siriporn; McLean, Gary N.

    2005-01-01

    To begin the validation process for the Learning Transfer System Inventory (LTSI) in Thailand, research replicating Holton, Bates, and Ruona's study (2000) was conducted in Thailand. The LTSI was administered to 1,029 employees. Exploratory factor analysis and MANOVA were used to identify factors. A factor structure almost identical to that of…

  15. Strategy of ring-shaped aggregates in excitation energy transfer for removing disorder-induced shielding

    NASA Astrophysics Data System (ADS)

    Tei, Go; Nakatani, Masatoshi; Ishihara, Hajime

    2013-06-01

    Peripheral light harvesting complex (LH2), which is found in photosynthetic antenna systems of purple photosynthetic bacteria, has important functions in the photosynthetic process, such as harvesting sunlight and transferring its energy to the photosynthetic reaction center. The key component in excitation energy transfer (EET) between LH2s is B850, which is a characteristic ring-shaped aggregate of pigments usually formed by 18 or 16 bacteriochlorophylls in LH2. We theoretically study the strategy of the ring-shaped aggregate structure, which maximizes EET efficiency, by using the standard Frenkel exciton model and the self-consistent calculation method for the Markovian quantum master equation and Maxwell equation. As a result, we have revealed a simple but ingenious strategy of the ring-shaped aggregate structure. The combination of three key properties of the ring unit system maximizes the EET efficiency, namely the large dipole moment of aggregates causes the basic improvement of EET efficiency, and the isotropic nature and the large occupying area are critically effective to remove the disorder-induced shielding that inhibits EET in the presence of the randomness of orientation and alignment of carriers of excitation energy.

  16. Utilising tetraphenylethene as a dual activator for intramolecular charge transfer and aggregation induced emission.

    PubMed

    Zhang, Guo-Feng; Aldred, Matthew P; Gong, Wen-Liang; Li, Chong; Zhu, Ming-Qiang

    2012-08-11

    We report a simple design and synthesis of a donor-acceptor tetraphenylethene-naphthalimide (TPE-NI) dyad, in which TPE acts both as an electron-donor for intramolecular charge transfer (ICT) and activator for aggregation induced emission (AIE). Strong solvent-dependent photoluminescence covering almost the whole visible spectrum and AIE in its nanoparticle state compared to its solution state are demonstrated. PMID:22745935

  17. An Aggregate IRT Procedure for Exploratory Factor Analysis

    ERIC Educational Resources Information Center

    Camilli, Gregory; Fox, Jean-Paul

    2015-01-01

    An aggregation strategy is proposed to potentially address practical limitation related to computing resources for two-level multidimensional item response theory (MIRT) models with large data sets. The aggregate model is derived by integration of the normal ogive model, and an adaptation of the stochastic approximation expectation maximization…

  18. Aggregation-induced emission: a simple strategy to improve chemiluminescence resonance energy transfer.

    PubMed

    Zhang, Lijuan; He, Nan; Lu, Chao

    2015-01-20

    The emergence of aggregation-induced emission (AIE) has opened up a new avenue for scientists. There is a great demand for the development of a new generation chemiluminescence resonance energy transfer (CRET) acceptors with AIE characteristics due to the aggregation-caused chemiluminescence (CL) quenching effect commonly observed in the conventional fluorophore CL acceptors at high concentrations. However, the systematical studies involving in AIE-amplified CL are still scarce. Herein, it is the first report that the gold nanocluster aggregates (a type of well-defined AIE molecules) are used to study their influence on the bis(2,4,6-trichlorophenyl) oxalate (TCPO)-H2O2 CL reaction. Interestingly, the AIE molecules in the diluted solution are unable to boost the CL signal of the TCPO-H2O2 system, but their aggregates display a strongly enhanced CL emission compared to their counterparts of fluorophore molecules, thanks to the unique AIE effect of gold nanoclusters. In comparison to rhodamine B with the aid of an imidazole catalyst, the detection limit of the gold nanocluster aggregate-amplified CL probe for H2O2 (S/N = 3) is low in the absence of any catalyst. Finally, the other two typical AIE molecules, Au(I)-thiolate complexes and 9,10-bis[4-(3-sulfonatopropoxyl)-styryl]anthracene (BSPSA), are investigated to verify the generality of the AIE molecule-amplified CL emissions. These results demonstrate effective access to highly fluorescent AIE molecules with practical applications in avoiding the aggregation-induced CL quenching at high concentrations, which can be expected to provide a novel and sensitive platform for the CL amplified detection. PMID:25526522

  19. Enhanced thermal conductivity by aggregation in heat transfer nanofluids containing metal oxide nanoparticles and carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Wensel, Jesse; Wright, Brian; Thomas, Dustin; Douglas, Wayne; Mannhalter, Bert; Cross, William; Hong, Haiping; Kellar, Jon; Smith, Pauline; Roy, Walter

    2008-01-01

    An approximately 10% increase in the thermal conductivity (TC) of heat transfer nanofluids containing metal oxide nanoparticles and carbon nanotubes has been determined with very low percentage loading (around 0.02wt%) of these two nanomaterials. These fluids are very stable and the viscosity remains approximately the same as water. A possible explanation for these interesting results is the aggregation of metal oxide particles on the surface of nanotubes by electrostatic attraction and form the aggregation chain along the nanotube. Time dependant magnetic results demonstrate that, under the influence of a strong outside magnetic field, the TC value decreases. Also, the TC value decreases when the pH is shifted from 7 to 11.45.

  20. Photoinduced charge-transfer dynamics simulations in noncovalently bonded molecular aggregates.

    PubMed

    Medrano, Carlos R; Oviedo, M Belén; Sánchez, Cristián G

    2016-06-01

    The rational design of new materials as prototype systems for organic solar cells remains challenging. Perylene diimide has emerged as a promising material to replace fullerene derivatives because of its synthetic flexibility, leading to the manipulation of their optical properties. As a result of their fused aromatic core that favors π-π stacking interactions, the aggregation of these molecules can reach highly ordered nanostructures as one-dimensional nanofibers, with a fast photoinduced charge transfer mechanism. In this article, we present an atomistic description of the photoexcited exciton dynamics in noncovalently bonded perylene diimides by time integration of the electron density in the presence of external time varying electric fields. We show that our approach is able to capture and explain the physics that underlies the charge transport mechanism through perylene diimide aggregates. PMID:27189740

  1. Frequency Factors in a Landscape Model of Filamentous Protein Aggregation

    NASA Astrophysics Data System (ADS)

    Buell, Alexander K.; Jamie R. Blundell; Dobson, Christopher M.; Welland, Mark E.; Terentjev, Eugene M.; Knowles, Tuomas P. J.

    2010-06-01

    Using quantitative measurements of protein aggregation rates, we develop a kinetic picture of protein conversion from a soluble to a fibrillar state which shows that a single free energy barrier to aggregation controls the addition of protein molecules into amyloid fibrils, while the characteristic sublinear concentration dependence emerges as a natural consequence of finite diffusion times. These findings suggest that this reaction does not follow a simple chemical mechanism, but rather operates in a way analogous to the landscape models of protein folding defined by stochastic dynamics on a characteristic energy surface.

  2. HESI EXPOSURE FACTORS DATABASE FOR AGGREGATE AND CUMULATIVE RISK ASSESSMENT

    EPA Science Inventory

    In recent years, the risk analysis community has broadened its use of complex aggregate and cumulative residential exposure models (e.g., to meet the requirements of the 1996 Food Quality Protection Act). The value of these models is their ability to incorporate a range of inp...

  3. Characteristics of Intramolecular Charge Transfer by J-Aggregates in Merocyanine Dye LB Films.

    PubMed

    Yang, Chang Heon; Kwon, Young-Soo; Shin, Hoon-Kyu

    2016-06-01

    In this study, for the development of future molecular electronic devices, we have investigated the characteristics of the aggregates of Langmuir-Blodgett films. The characteristics of intramolecular charge transfer by J-aggregates in merocyanine dye LB films have been studied experimentally by using UV irradiation and heat treatment. In addition to intramolecular charge transfer, we also studied the conjugation and energy changes of the molecules. In case a dye is thinned by LB method, the alkyl chain is often displaced in order to form a mono-molecular film with ease. Since the molecular association form is often made by self-organization of molecules themselves, in case the dye and the alkyl chain are strongly bonded by the covalent bond, it may be said that the properties of the LB film to be built up are almost determined at the time of synthesis of film-forming molecules. Meanwhile, since, in case LB film is fabricated by the diffusion absorption method, the cohesive force between the water-soluble dye and the surface-active mono-molecular film is electrostatic, the dye molecule can move relatively freely on the air/water interface, which may be regarded as a two-dimensional crystal growth process. PMID:27427711

  4. Photoinduced electron transfer reaction in polymer-surfactant aggregates: Photoinduced electron transfer between N,N-dimethylaniline and 7-amino coumarin dyes

    SciTech Connect

    Chakraborty, Anjan; Seth, Debabrata; Setua, Palash; Sarkar, Nilmoni

    2008-05-28

    Photoinduced electron transfer between coumarin dyes and N,N-dimethylaniline has been investigated by using steady state and picosecond time resolved fluorescence spectroscopy in sodium dodecyl sulphate (SDS) micelles and PVP-polyvinyl pyrrolidone (SDS) polymer-surfactant aggregates. A slower rate of electron transfer is observed in PVP-SDS aggregates than in polymer-free SDS micelles. A Marcus type inversion is observed in the correlation of free energy change in comparison with the electron transfer rate. The careful investigation reveals that C-151 deviates from the normal Marcus inverted region compared to its analogs C-152 and C-481 due to slower rotational relaxation and smaller translational diffusion coefficient.

  5. The Effect of Ovine Secreted Soluble Factors on Human Dermal Papilla Cell Aggregation

    PubMed Central

    Sari, Agnes Rosarina Prita; Rufaut, Nicholas Wolfgang; Jones, Leslie Norman; Sinclair, Rodney Daniel

    2016-01-01

    Context: In androgenetic alopecia, follicular miniaturization and dynamic changes to the hair cycle produce patterned baldness. The most effective treatment for baldness is hair transplantation surgery. The major limitation to hair transplantation is the availability of donor hair from the relatively unaffected occipital scalp. Hair induction with in vitro expansion of donor follicle populations has the potential to overcome this. The major obstacle to this is that in vitro expansion of human dermal papilla cell (DPC) colonies is associated with irreversible loss of aggregative behavior and hair follicle-inductive potential. In contrast, cultured ovine DPCs maintain these properties after extensive proliferation. Aims: To determine whether aggregating ovine DPC secrete factors that enhance the aggregative behavior or inductive potential of human DPC. Subjects and Methods: Fluorescently-labelled ovine DPC were mixed in culture with human DPC at passage number seven-nine, which had lost their aggregative behavior. The effects of different culture substrates and medium compositions on aggregative behavior were determined. Ovine and human papilla cells were co-cultured, separated by a permeable membrane to determine whether the ovine cells secrete soluble factors that affect human papilla cells. Results: In direct co-culture experiments, well-formed aggregates were produced by 90:10 human:ovine and 50:50 human:ovine DPC mixtures. In contrast, unmixed human DPC remained in a monolayer state after 18 days. Both human and ovine DPC had a higher tendency to aggregate in medium containing 20% (v/v) lamb serum (LS) compared to 10% (v/v) fetal calf serum (FCS). In co-culture experiments separated with permeable membrane, the human DPC aggregates were bigger and more rapidly formed with the addition of ovine secreted soluble factors. Conclusions: Soluble factors secreted by ovine DPC and present in LS increase the aggregative behavior of human DPC. These molecules might

  6. Effect of social and environmental factors on ant aggregation: a general response?

    PubMed

    Depickère, Stéphanie; Fresneau, Dominique; Deneubourg, Jean-Louis

    2008-09-01

    In social species, the interactions that occur between individuals and also between individuals and their environment can lead to various spatial distributions. Our goal was to understand how both factors (social and environmental) can affect such spatial distribution of individuals. Aggregation experiments were conducted on the ant Crematogaster scutellaris: the level of inter-attraction between individuals was characterized and the influence of an environmental factor (light intensity) was studied. Two ethological castes (brood-tenders and foragers) were tested, showing a strong and similar aggregation pattern-although faster for foragers. This difference could be explained by a higher degree of inter-attraction for brood-tenders, resulting in longer interaction time and therefore a slower aggregation rate. We also showed the influence of light conditions by carrying out experiments in total darkness and under red light. C. scutellaris appeared highly sensitive to the red light, aggregating just underneath it. Nevertheless, the level of aggregation is not affected by the luminosity condition. These results are discussed in relation to the ecology of the species, and are compared with results obtained in another ant species, Lasius niger, which exhibits a similar response to aggregation. We propose, therefore, a general link between the level/pattern of aggregation and polyethism in ants. PMID:18706421

  7. Energy transfer dynamics in trimers and aggregates of light-harvesting complex II probed by 2D electronic spectroscopy

    SciTech Connect

    Enriquez, Miriam M.; Zhang, Cheng; Tan, Howe-Siang; Akhtar, Parveen; Garab, Győző; Lambrev, Petar H.

    2015-06-07

    The pathways and dynamics of excitation energy transfer between the chlorophyll (Chl) domains in solubilized trimeric and aggregated light-harvesting complex II (LHCII) are examined using two-dimensional electronic spectroscopy (2DES). The LHCII trimers and aggregates exhibit the unquenched and quenched excitonic states of Chl a, respectively. 2DES allows direct correlation of excitation and emission energies of coupled states over population time delays, hence enabling mapping of the energy flow between Chls. By the excitation of the entire Chl b Q{sub y} band, energy transfer from Chl b to Chl a states is monitored in the LHCII trimers and aggregates. Global analysis of the two-dimensional (2D) spectra reveals that energy transfer from Chl b to Chl a occurs on fast and slow time scales of 240–270 fs and 2.8 ps for both forms of LHCII. 2D decay-associated spectra resulting from the global analysis identify the correlation between Chl states involved in the energy transfer and decay at a given lifetime. The contribution of singlet–singlet annihilation on the kinetics of Chl energy transfer and decay is also modelled and discussed. The results show a marked change in the energy transfer kinetics in the time range of a few picoseconds. Owing to slow energy equilibration processes, long-lived intermediate Chl a states are present in solubilized trimers, while in aggregates, the population decay of these excited states is significantly accelerated, suggesting that, overall, the energy transfer within the LHCII complexes is faster in the aggregated state.

  8. A factor from Actinomyces viscosus T14V that specifically aggregates Streptococcus sanguis H1.

    PubMed Central

    Mizuno, J; Cisar, J O; Vatter, A E; Fennessey, P V; McIntire, F C

    1983-01-01

    A highly specific aggregation factor for Streptococcus sanguis H1 (AFH1) was obtained by lysozyme treatment of Actinomyces viscosus T14V. At 1 micrograms/ml, AFH1 aggregated a suspension of S. sanguis H1, with which A. viscosus T14V coaggregates by a mechanism not inhibited by lactose: even at much higher levels AFH1 caused little or no aggregation of streptococci from other coaggregation groups (J. O. Cisar et al., Infect. Immun. 24:742-752, 1979). The most active fraction of AFH1 obtained by gel chromatography (near the void volume of Bio-Gel A1.5 m) reacted as a single antigen with anti-A. viscosus T14V serum and was unrelated to the fimbrial antigens of A. viscosus T14V. Smaller molecular fractions, at high levels, inhibited aggregation of S. sanguis H1 by high-molecular-weight AFH1 as well as coaggregation of S. sanguis H1 with A. viscosus T14V. The AFH1 fraction with high aggregating activity was composed of approximately 53% cell wall components (alanine, glutamine, lysine, N-acetylglucosamine, and N-acetylmuramic acid). 40% polysaccharide (N-acetylgalactosamine, rhamnose, and 6-deoxytalose), and 7% protein; teichoic acid was not detected. The fraction which inhibited aggregation and coaggregation contained much less of the cell wall constituents and more of the polysaccharide than the fraction with potent aggregating activity. Aggregation was completely prevented either by treating AFH1 with 0.01 M periodate at 25 degrees C for 4 h or by treating S. sanguis H1 with heat or pronase. A role for electrostatic forces in the aggregation was indicated by: (i) NaCl inhibition of aggregation, and (ii) a great decrease in aggregation potency as a result of chemical modification of either cationic or anionic groups of AFH1. On the other hand, NaCl reversed the aggregation only very weakly. The overall data suggest that a carbohydrate-protein interaction may be dominant in the aggregation of S. sanguis H1 by AFH1 and in the coaggregation of S. sanguis H1 with A

  9. Confirmatory Factor Analysis of Transfer Student Adjustment

    ERIC Educational Resources Information Center

    Young, Jacob T. N.; Litzler, Elizabeth

    2013-01-01

    Transfer students' adjustment to college has received substantial attention by researchers. This focus has predominately investigated the observation of "transfer shock": a decrease in grade point average (GPA) experienced after transferring. In response to the persistent focus on transfer shock, growing attention has been directed…

  10. Enterococcus faecalis Ebp pili are important for cell-cell aggregation and intraspecies gene transfer.

    PubMed

    La Rosa, Sabina Leanti; Montealegre, Maria Camila; Singh, Kavindra V; Murray, Barbara E

    2016-05-01

    Enterococcus faecalis is an opportunistic pathogen that ranks among the leading causes of biofilm-associated infections. We previously demonstrated that the endocarditis- and biofilm-associated pili (Ebp) of E. faecalis play a major role in biofilm formation, adherence to abiotic surfaces and experimental infections. In this study, derivatives of E. faecalis strain OG1 were engineered to further characterize functions of Ebp pili. Loss of pili resulted in a 36-fold decrease in the number of closely associated cells when OG1RFΔebpABC was mixed with OG1SSpΔebpABC, compared with mixing the Ebp+ parental strains. In addition, using the Ebp+ parental strains as donor and recipient, we found a statistically significant increase (280-360 %, P < 0.05) in the frequency of plasmid transfer versus using Ebp-  mutants in the conjugation experiments. These results demonstrate a previously unrecognized role of Ebp pili, namely, as important contributors to microscale cell aggregation and horizontal spread of genetic material. PMID:26967674

  11. Embryo aggregation does not improve the development of interspecies somatic cell nuclear transfer embryos in the horse.

    PubMed

    Gambini, Andrés; De Stéfano, Adrián; Jarazo, Javier; Buemo, Carla; Karlanian, Florencia; Salamone, Daniel Felipe

    2016-09-01

    The low efficiency of interspecies somatic cell nuclear transfer (iSCNT) makes it necessary to investigate new strategies to improve embryonic developmental competence. Embryo aggregation has been successfully applied to improve cloning efficiency in mammals, but it remains unclear whether it could also be beneficial for iSCNT. In this study, we first compared the effect of embryo aggregation over in vitro development and blastocyst quality of porcine, bovine, and feline zona-free (ZF) parthenogenetic (PA) embryos to test the effects of embryo aggregation on species that were later used as enucleated oocytes donors in our iSCNT study. We then assessed whether embryo aggregation could improve the in vitro development of ZF equine iSCNT embryos after reconstruction with porcine, bovine, and feline ooplasm. Bovine- and porcine-aggregated PA blastocysts had significantly larger diameters compared with nonaggregated embryos. On the other hand, feline- and bovine-aggregated PA embryos had higher blastocyst cell number. Embryo aggregation of equine-equine SCNT was found to be beneficial for embryo development as we have previously reported, but the aggregation of three ZF reconstructed embryos did not improve embryo developmental rates on iSCNT. In vitro embryo development of nonaggregated iSCNT was predominantly arrested around the stage when transcriptional activation of the embryonic genome is reported to start on the embryo of the donor species. Nevertheless, independent of embryo aggregation, equine blastocyst-like structures could be obtained in our study using domestic feline-enucleated oocytes. Taken together, these results reported that embryo aggregation enhance in vitro PA embryo development and embryo quality but effects vary depending on the species. Embryo aggregation also improves, as expected, the in vitro embryo development of equine-equine SCNT embryos; however, we did not observe positive effects on equine iSCNT embryo development. Among oocytes

  12. Aggregation-induced emission of diarylamino-π-carborane triads: effects of charge transfer and π-conjugation.

    PubMed

    Cho, Yang-Jin; Kim, So-Yoen; Cho, Minji; Han, Won-Sik; Son, Ho-Jin; Cho, Dae Won; Kang, Sang Ook

    2016-04-14

    Carborane-based donor-π-acceptor triads (D-π-A-π-D) bearing triarylamine moieties were synthesised. All the monomeric triads showed a blue-green emission in a dilute solution, which was assigned as an intramolecular charge-transfer (CT) emission. The intramolecular CT emission showed large Stokes shifts at a higher solvent polarity. The intramolecular CT emission further shifted to a longer wavelength with the increase in π-conjugation. Interestingly, a strong red emission was observed in highly concentrated solutions or in the solid state, which was assigned as an aggregation-induced emission (AIE). Moreover, the AIE strongly depended on solvent polarity. A large Stokes shift in AIE was attributed to the strong CT character. The changes in the dipole moment for the AIE state and monomer emission were evaluated using the Lippert-Mataga relationship. The density functional theory calculations showed that the change in electron distribution between the aryl amino group (highest occupied molecular orbital, HOMO) and the carborane moiety (lowest unoccupied molecular orbital, LUMO) indicates the intramolecular CT character, and the emission colour changes were attributed to the HOMO-LUMO energy gap controlled by the π-extension of the phenylene linker. The electrochemical properties such as oxidation and reduction potentials were consistent with theoretical calculation results. The emission properties were affected by two main factors: solvent polarity and solubility. PMID:26996491

  13. Structure and Excitation Transfer Pathways in the Chlorophyll-Carotenoid Aggregate of the Photosynthetic Unit of Purple Bacteria

    NASA Astrophysics Data System (ADS)

    Schulten, Klaus

    1998-03-01

    The absorption of light by light harvesting complexes and transfer of electronic excitation to the photosynthetic reaction center (RC) has been investigated on the basis of an atomic level model of the so-called photosynthetic unit of the photosynthetic bacterium Rb. sphaeroides. The photosynthetic unit combines in the intracytoplasmic membrane a nanometric (20-100 nm) assembly of three protein complexes: (i) the photosynthetic reaction center, (ii) a ring-shaped light harvesting complex LH-I, and (iii) multiple copies of a similar complex, LH-II. The unit has been modeled using the known structure of LH-II of Rs. molischianum. The lecture describes in detail the organization of chromophores involved in primary light absorption and excitation transfer: a hierarchy of ring-shaped chlorophyl aggregates with attached carotenoids. A quantum-mechanical description of the entire light harvesting process is developed employing electron structure calculations of individual and aggregated chlorophylls and carotenoids and associated effective Hamiltonian descriptions. The transfer times calculated, ranging between 100 fs and 100 ps for various processes, are found in close agreement with measured transfer rates. The results suggest that excitons are the key carriers of the excitation transfered. The photoprotection of chlorophylls by chlorophylls through triplet excitation transfer is also described.

  14. Different Factors for Different Causes: Analysis of the Spatial Aggregations of Fire Ignitions in Catalonia (Spain).

    PubMed

    González-Olabarria, José Ramón; Mola-Yudego, Blas; Coll, Lluis

    2015-07-01

    The present study analyzes the effects of different socioeconomic factors on the frequency of fire ignition occurrence, according to different original causes. The data include a set of documented ignition points in the region of Catalonia for the period 1995-2008. The analysis focused on the spatial aggregation patterns of the ignitions for each specific ignition cause. The point-based data on ignitions were interpolated into municipality-level information using kernel methods as the basis for defining five ignition density levels. Afterwards, the combination of socioeconomic factors influencing the ignition density levels of the municipalities was analyzed for each documented cause of ignition using a principal component analysis. The obtained results confirmed the idea that both the spatial aggregation patterns of fire ignitions and the factors defining their occurrence were specific for each of the causes of ignition. Intentional fires and those of unknown origin were found to have similar spatial aggregation patterns, and the presence of high ignition density areas was related to high population and high unemployment rates. Additionally, it was found that fires originated from forest work, agricultural activities, pasture burning, and lightning had a very specific behavior on their own, differing from the similarities found on the spatial aggregation of ignitions originated from smokers, electric lines, machinery, campfires, and those of intentional or unknown origin. PMID:25736559

  15. Structural Basis for Protein anti-Aggregation Activity of the Trigger Factor Chaperone*

    PubMed Central

    Saio, Tomohide; Guan, Xiao; Rossi, Paolo; Economou, Anastassios; Kalodimos, Charalampos G.

    2014-01-01

    Molecular chaperones prevent aggregation and misfolding of proteins but scarcity of structural data has impeded an understanding of the recognition and anti-aggregation mechanisms. Here we report the solution structure, dynamics and energetics of three Trigger Factor (TF) chaperone molecules in complex with alkaline phosphatase (PhoA) captured in the unfolded state. Our data show that TF uses multiple sites to bind to several regions of the PhoA substrate protein primarily through hydrophobic contacts. NMR relaxation experiments show that TF interacts with PhoA in a highly dynamic fashion but as the number and length of the PhoA regions engaged by TF increases, a more stable complex gradually emerges. Multivalent binding keeps the substrate protein in an extended, unfolded conformation. The results show how molecular chaperones recognize unfolded polypeptides and how by acting as unfoldases and holdases prevent the aggregation and premature (mis)folding of unfolded proteins. PMID:24812405

  16. Factors Affecting Training Transfer: Participants' Motivation to Transfer Training, Literature Review

    ERIC Educational Resources Information Center

    Alawneh, Muhammad K.

    2008-01-01

    This article investigates factors that motivate participants in learning and training activities to transfer skills, knowledge and attitude from the learning setting to the workplace. Based on training transfer theories hypothesized by Holton (1996), one of the major theories that affect an organization's learning is motivation to transfer theory.…

  17. Aggregation of germlings is a major contributing factor towards mycelial heterogeneity of Streptomyces

    PubMed Central

    Zacchetti, Boris; Willemse, Joost; Recter, Brand; van Dissel, Dino; van Wezel, Gilles P.; Wösten, H. A. B.; Claessen, Dennis

    2016-01-01

    Streptomycetes are filamentous bacteria that produce numerous valuable compounds, including the majority of clinically used antibiotics. At an industrial scale, most of these compounds are produced in bioreactors. Growth of streptomycetes under these conditions is characterized by the formation of complex mycelial particles, whose sizes follow a bimodal distribution. Given the correlation between specific productivity and morphology, this size heterogeneity poses a potential drawback in industry. Recent work indicates that mycelial morphology is controlled by a number of genes that encode proteins required for the synthesis of cell surface-associated glycans. Using a quantifiable system based on fluorescent markers, we here show that these glycans mediate aggregation between germlings and young mycelia, yielding mycelial particles that originate from many different individuals. We also demonstrate that at later time points aggregation between distinct particles is no longer detectable. Notably, the absence of the corresponding glycan synthases yields mycelia that are homogeneous in size, identifying mycelial aggregation as a driving factor towards size heterogeneity. Given that aggregation is widespread within streptomycetes and can also occur between different Streptomyces strains, our work paves the way to improve Streptomyces as a cell factory for the production of known metabolites, but possibly also to discover new ones. PMID:27244565

  18. Aggregation of germlings is a major contributing factor towards mycelial heterogeneity of Streptomyces.

    PubMed

    Zacchetti, Boris; Willemse, Joost; Recter, Brand; van Dissel, Dino; van Wezel, Gilles P; Wösten, H A B; Claessen, Dennis

    2016-01-01

    Streptomycetes are filamentous bacteria that produce numerous valuable compounds, including the majority of clinically used antibiotics. At an industrial scale, most of these compounds are produced in bioreactors. Growth of streptomycetes under these conditions is characterized by the formation of complex mycelial particles, whose sizes follow a bimodal distribution. Given the correlation between specific productivity and morphology, this size heterogeneity poses a potential drawback in industry. Recent work indicates that mycelial morphology is controlled by a number of genes that encode proteins required for the synthesis of cell surface-associated glycans. Using a quantifiable system based on fluorescent markers, we here show that these glycans mediate aggregation between germlings and young mycelia, yielding mycelial particles that originate from many different individuals. We also demonstrate that at later time points aggregation between distinct particles is no longer detectable. Notably, the absence of the corresponding glycan synthases yields mycelia that are homogeneous in size, identifying mycelial aggregation as a driving factor towards size heterogeneity. Given that aggregation is widespread within streptomycetes and can also occur between different Streptomyces strains, our work paves the way to improve Streptomyces as a cell factory for the production of known metabolites, but possibly also to discover new ones. PMID:27244565

  19. Methylene transfer or carbometalation? A theoretical study to determine the mechanism of lithium carbenoid-promoted cyclopropanation reactions in aggregation and solvation States.

    PubMed

    Ke, Zhuofeng; Zhao, Cunyuan; Phillips, David Lee

    2007-02-01

    Density functional theory calculations for the lithium carbenoid-promoted cyclopropanations in aggregation and solvation states are presented in order to investigate the controversy of the mechanistic dichotomy, that is, the methylene-transfer mechanism and the carbometalation mechanism. The methylene-transfer mechanism represents the reaction reality, whereas the carbometalation pathway does not appear to compete significantly with the methylene-transfer pathway and should be ruled out as a major factor. A simple model calculation for monomeric lithium carbenoid-promoted cyclopropanations with ethylene in the gas phase is not sufficient to reflect the reaction conditions accurately or to determine the reaction mechanism since its result is inconsistent with the experimental facts. The aggregated lithium carbenoids are the most probable reactive species in the reaction system. The calculated reaction barriers of the methylene-transfer pathways are 10.1 and 8.0 kcal/mol for the dimeric (LiCH2F)2 and tetrameric (LiCH2F)4 species, respectively, compared with the reaction barrier of 16.0 kcal/mol for the monomeric LiCH2F species. In contrast, the reaction barriers of the carbometalation pathways are 26.8 kcal/mol for the dimeric (LiCH2F)2 and 33.9 kcal/mol for the tetrameric (LiCH2F)4 species, compared with the reaction barrier of 12.5 kcal/mol for the monomeric LiCH2F species. The effects of solvation were investigated by explicit coordination of the solvent molecules to the lithium centers. This solvation effect is found to enhance the methylene-transfer pathway, while it is found to impede the carbometalation pathway instead. The combined effects of the aggregation and solvation lead to barriers to reaction in the range of 7.2-9.0 kcal/mol for lithium carbenoid-promoted cyclopropanation reactions along the methylene-transfer pathway. Our computational results are in good agreement with the experimental observations. PMID:17253804

  20. Racial and Cultural Factors and Learning Transfer

    ERIC Educational Resources Information Center

    Closson, Rosemary

    2013-01-01

    Baldwin and Ford (1988) specifically include learner characteristics as one of three key inputs into the learning transfer process but infrequently (actually almost never) has race, ethnicity, or culture been included as a variable when describing trainee characteristics. For the most part one is left to speculate as to the potential influence…

  1. Some Factors Influencing Transfer of Simulator Training.

    ERIC Educational Resources Information Center

    Caro, Paul W.

    Studies of transfer of training may be used to determine whether simulator training improves pilot performance in an aircraft. Some approaches to determining simulator training effectiveness, such as surveys of pilot and instructor opinions, are not considered particularly reliable. Several other approaches have also been suggested. One factor…

  2. Ingestion Pathway Transfer Factors for Plutonium and Americium

    SciTech Connect

    Blanchard, A.

    1999-07-28

    Overall transfer factors for major ingestion pathways are derived for plutonium and americium. These transfer factors relate the radionuclide concentration in a given foodstuff to deposition on the soil. Equations describing basic relationships consistent with Regulatory Guide 1.109 are followed. Updated values and coefficients from IAEA Technical Reports Series No. 364 are used when a available. Preference is given to using factors specific to the Savannah River Site.

  3. Electronic and Nuclear Factors in Charge and Excitation Transfer

    SciTech Connect

    Piotr Piotrowiak

    2004-09-28

    We report the and/or state of several subprojects of our DOE sponsored research on Electronic and Nuclear Factors in Electron and Excitation Transfer: (1) Construction of an ultrafast Ti:sapphire amplifier. (2) Mediation of electronic interactions in host-guest molecules. (3) Theoretical models of electrolytes in weakly polar media. (4) Symmetry effects in intramolecular excitation transfer.

  4. A Compendium of Transfer Factors for Agricultural and Animal Products

    SciTech Connect

    Staven, Lissa H.; Napier, Bruce A.; Rhoads, Kathleen; Strenge, Dennis L.

    2003-06-02

    Transfer factors are used in radiological risk assessments to estimate the amount of radioactivity that could be present in a food crop or organism based on the calculated concentration in the source medium (i.e., soil or animal feed). By calculating the concentration in the food, the total intake can be estimated and a dose calculated as a result of the annual intake. This report compiles transfer factors for radiological risk assessments, using common food products, including meats, eggs, and plants. Transfer factors used were most often selected from recommended values listed by national or international organizations for use in radiological food chain transport calculations. Several methods of estimation and extrapolation were used for radionuclides not listed in the primary information sources. Tables of transfer factors are listed by element and information source for beef, eggs, fish, fruit, grain, leafy vegetation, milk, poultry, and root vegetables.

  5. Factors affecting crystallization, dispersion, and aggregation of calcium oxalate monohydrate in various urinary environments

    NASA Astrophysics Data System (ADS)

    Christmas, Kimberly Gail

    The mechanisms for the formation of kidney stones are not well understood. One possible mechanism is the formation of aggregates in the nephron tubules of the kidneys. However, altering the urinary environment may be a method to help prevent the recurrence of the formation of kidney stones. The primary inorganic constituent found in kidney stones of North American patients is calcium oxalate monohydrate (COM). In this research, studies on the effect of mixing rate on COM precipitation showed that rapid mixing compared to slow mixing produced smaller particle sizes and a narrower particle size distribution due to the more uniform supersaturation level. The findings are consistent with the general contention that mixing directly influences nucleation rate while mixing rate has relatively little influence over rate of growth in precipitation processes. Screening and central composite experimental designs are used to determine the effect of various factors on the aggregation and dispersion characteristics of previously grown calcium oxalate monohydrate (COM) crystals in artificial urinary environments of controlled variables. The variables examined are pH, calcium, oxalate, pyrophosphate, citrate, and protein concentrations in ultrapure water and artificial urine. Optical density measurements, zeta potential analysis, particle size analyzer, optical microscopy, AFM force measurements, protein adsorption, and ions and small molecule adsorption have been used to assess the state of aggregation and dispersion of the COM crystals and to elucidate the mechanisms involved in such a complex system. The data indicate that our model protein, mucin, acts as a dispersant. This is attributed to steric hindrance resulting from the adsorbed mucoprotein. Oxalate, however, promotes aggregation. Interesting interactions between protein and oxalate along with protein and citrate are observed. Such interactions (synergistic or antagonistic) are found to depend on the concentrations of

  6. Electron transfer mediation by aqueous C₆₀ aggregates in H₂O₂/UV advanced oxidation of indigo carmine.

    PubMed

    Ge, Ling; Moor, Kyle; Zhang, Bo; He, Yiliang; Kim, Jae-Hong

    2014-11-21

    C60 fullerene has long been known to exhibit favorable electron accepting and shuttling properties, but little is known about the possibility of electron transfer mediation by fullerene aggregates (nC60) in water. In this study, we investigated the electron shuttling capabilities of nC60 using UV/H2O2 as a model oxidation process in the presence of an electron donor, indigo carmine (IC). nC60 addition to the IC/H2O2 system was found to drastically increase IC degradation and shift the reactive oxygen species (ROS) balance, favoring the formation of superoxide and perhydroxyl radical species compared to hydroxyl radicals. Results indicate that nC60 can act as an electron mediator, where the adsorbed IC donates an electron to nC60, which is subsequently transferred to H2O2 or perhydroxyl radical. PMID:25268845

  7. Binding and aggregation of pro-atrial natriuretic factor by calcium.

    PubMed

    Thibault, G; Doubell, A F

    1992-04-01

    Analysis of atrial secretory granule content by sodium dodecyl sulfate-gel electrophoresis followed by a 45Ca2+ overlay assay indicates that a 17,000 protein binds 45Ca2+. This protein, which can be immunostained by atrial natriuretic factor (ANF) antiserum, corresponds to proANF. Ca2+ binding is proportional to the amount of proANF and pH dependent. Generation of ANF-(1-98) by thrombin digestion of proANF does not affect Ca2+ binding. Blocking the carboxyl groups of proANF and the use of NH2-terminal fragments bearing those carboxyl groups demonstrated that the Ca(2+)-interaction site is probably located within the highly acidic portion (11-30) of the propeptide. Ca2+ binding to proANF induces its aggregation that can be verified by sedimentation. ProANF aggregation is Ca2+ dependent, being optimal at 10 mM, partially pH dependent, and greatly increased by high concentrations of proANF. However, because of its relatively low-binding affinity, Ca2+ can be substituted by other divalent cations such as Sr2+, Ba2+, or Mg2+. The high level of Ca2+ in atrial secretory granules and the aggregation of proANF in the presence of Ca2+ suggest a possible involvement of these physicochemical properties in the condensed state of the matrix of secretory granules. Indeed, detergent solubilization of the membrane of the secretory granules in presence of Ca2+ resulted only in a partial dissolution of the dense core matrix. We therefore postulate that, in the Golgi complex, proANF and Ca2+ associate to form a condensed aggregate that helps package secretory material into secretory vesicles. PMID:1533094

  8. Electron transfer mediation by aqueous C60 aggregates in H2O2/UV advanced oxidation of indigo carmine

    NASA Astrophysics Data System (ADS)

    Ge, Ling; Moor, Kyle; Zhang, Bo; He, Yiliang; Kim, Jae-Hong

    2014-10-01

    C60 fullerene has long been known to exhibit favorable electron accepting and shuttling properties, but little is known about the possibility of electron transfer mediation by fullerene aggregates (nC60) in water. In this study, we investigated the electron shuttling capabilities of nC60 using UV/H2O2 as a model oxidation process in the presence of an electron donor, indigo carmine (IC). nC60 addition to the IC/H2O2 system was found to drastically increase IC degradation and shift the reactive oxygen species (ROS) balance, favoring the formation of superoxide and perhydroxyl radical species compared to hydroxyl radicals. Results indicate that nC60 can act as an electron mediator, where the adsorbed IC donates an electron to nC60, which is subsequently transferred to H2O2 or perhydroxyl radical.C60 fullerene has long been known to exhibit favorable electron accepting and shuttling properties, but little is known about the possibility of electron transfer mediation by fullerene aggregates (nC60) in water. In this study, we investigated the electron shuttling capabilities of nC60 using UV/H2O2 as a model oxidation process in the presence of an electron donor, indigo carmine (IC). nC60 addition to the IC/H2O2 system was found to drastically increase IC degradation and shift the reactive oxygen species (ROS) balance, favoring the formation of superoxide and perhydroxyl radical species compared to hydroxyl radicals. Results indicate that nC60 can act as an electron mediator, where the adsorbed IC donates an electron to nC60, which is subsequently transferred to H2O2 or perhydroxyl radical. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr03647f

  9. Transfer of chemicals from feed to animal products: The use of transfer factors in risk assessment.

    PubMed

    Leeman, W R; Van Den Berg, K J; Houben, G F

    2007-01-01

    The human risk assessment of feed contaminants has often been hampered by a lack of knowledge concerning their behaviour when consumed by livestock. To gain a better understanding of the transfer of contaminants from animal feed to animal products, a meta-analysis of public literature was made. Data concerning feed contaminant concentrations, feeding periods, residue levels in animal products, and other parameters were gathered and recorded. For each case a 'transfer factor', which was defined as the ratio of the concentration of a chemical in an animal product to the concentration of the chemical in animal feed, was calculated. Scientifically founded transfer factors were calculated and analysed for groups of chemicals based on their contaminant classes or physicochemical properties. These database-derived transfer factors enable a more accurate risk assessment in the case of a feed contamination, and enable rapid risk management decision-making and/or intervention. PMID:17164211

  10. Maize beta-glucosidase-aggregating factor is a polyspecific jacalin-related chimeric lectin, and its lectin domain is responsible for beta-glucosidase aggregation.

    PubMed

    Kittur, Farooqahmed S; Lalgondar, Mallikarjun; Yu, Hyun Young; Bevan, David R; Esen, Asim

    2007-03-01

    In certain maize genotypes, called "null," beta-glucosidase does not enter gels and therefore cannot be detected on zymograms after electrophoresis. Such genotypes were originally thought to be homozygous for a null allele at the glu1 gene and thus devoid of enzyme. We have shown that a beta-glucosidase-aggregating factor (BGAF) is responsible for the "null" phenotype. BGAF is a chimeric protein consisting of two distinct domains: the disease response or "dirigent" domain and the jacalin-related lectin (JRL) domain. First, it was not known whether the lectin domain in BGAF is functional. Second, it was not known which of the two BGAF domains is involved in beta-glucosidase binding and aggregation. To this end, we purified BGAF to homogeneity from a maize null inbred line called H95. The purified protein gave a single band on SDS-PAGE, and the native protein was a homodimer of 32-kDa monomers. Native and recombinant BGAF (produced in Escherichia coli) agglutinated rabbit erythrocytes, and various carbohydrates and glycoproteins inhibited their hemagglutination activity. Sugars did not have any effect on the binding of BGAF to the beta-glucosidase isozyme 1 (Glu1), and the BGAF-Glu1 complex could still bind lactosyl-agarose, indicating that the sugar-binding site of BGAF is distinct from the beta-glucosidase-binding site. Neither the dirigent nor the JRL domains alone (produced separately in E. coli) produced aggregates of Glu1 based on results from pull-down assays. However, gel shift and competitive binding assays indicated that the JRL domain binds beta-glucosidase without causing it to aggregate. These results with those from deletion mutagenesis and replacement of the JRL domain of a BGAF homolog from sorghum, which does not bind Glu1, with that from maize allowed us to conclude that the JRL domain of BGAF is responsible for its lectin and beta-glucosidase binding and aggregating activities. PMID:17210577

  11. Temperature- and field-dependent energy transfer in CdSe nanocrystal aggregates studied by magneto-photoluminescence spectroscopy.

    PubMed

    Blumling, Daniel E; Tokumoto, Takahisa; McGill, Stephen; Knappenberger, Kenneth L

    2012-08-21

    The influence of temperature and applied magnetic fields on photoluminescence (PL) emission and electronic energy transfer (ET) of both isolated and aggregated CdSe nanocrystals was investigated. Following 400-nm excitation, temperature-dependent, intensity-integrated and energy-resolved PL measurements were used to quantify the emission wavelength and amplitude of isolated CdSe nanocrystals. The results indicated an approximately three-fold increase in PL intensity upon decreasing the temperature from 300 K to 6 K; this was attributed to a reduction of charge carrier access to nanocrystal surface trap states and suppression of thermal loss channels. Temperature-dependent PL measurements of aggregated CdSe nanocrystals, which included both energy-donating and -accepting particles, were analyzed using a modified version of Förster theory. Temperature-dependent ET efficiency increased from 0.55 to 0.75 upon decreasing the sample temperature from 225 K to 6 K, and the ET data contained the same trend observed for the PL of isolated nanoclusters. The application of magnetic fields to increase nanocrystal ET efficiency was studied using magneto-photoluminescence measurements recorded at a sample temperature of 1.6 K. We demonstrated that the exciton fine structure population of the donor was varied using applied magnetic fields, which in turn dictated the PL yield and the resultant ET efficiency of the CdSe nanocrystal aggregate system. The experimental data indicated an ET efficiency enhancement of approximately 7%, which was limited by the random orientation of the spherical nanocrystals in the thin film. PMID:22767253

  12. Effects of platelet inhibitors on propyl gallate-induced platelet aggregation, protein tyrosine phosphorylation, and platelet factor 3 activation.

    PubMed

    Xiao, Hongyan; Kovics, Richard; Jackson, Van; Remick, Daniel G

    2004-04-01

    Propyl gallate (PG) is a platelet agonist characterized by inducing platelet aggregation, protein tyrosine phosphorylation, and platelet factor 3 activity. The mechanisms of platelet activation following PG stimulation were examined by pre-incubating platelets with well-defined platelet inhibitors using platelet aggregation, protein tyrosine phosphorylation, activated plasma clotting time, and annexin V binding by flow cytometry. PG-induced platelet aggregation and tyrosine phosphorylation of multiple proteins were substantially abolished by aspirin, apyrase, and abciximab (c7E3), suggesting that PG is associated with activation of platelet cyclooxygenase 1, adenosine phosphate receptors, and glycoprotein IIb/IIIa, respectively. The phosphorylation of the cytoskeletal enzyme pp60(c-src) increased following PG stimulation, but was blunted by pre-incubation of platelets with aspirin, apyrase, and c7E3, suggesting that tyrosine kinase is important for the signal transduction of platelet aggregation. Propyl gallate also activates platelet factor 3 by decreasing the platelet coagulation time and increasing platelet annexin V binding. Platelet incubation with aspirin, apyrase, and c7E3 did not alter PG-induced platelet coagulation and annexin V binding. The results suggest that platelet factor 3 activation and membrane phosphotidylserine expression were not involved with activation of platelet cyclooxygenase, adenosine phosphate receptors, and glycoprotein IIb/IIIa. PG is unique in its ability to stimulate platelet aggregation and coagulation simultaneously, and platelet inhibitors in this study affect only platelet aggregation but not platelet coagulation. PMID:15060414

  13. Humidity and aggregate content correction factors for air-coupled ultrasonic evaluation of concrete.

    PubMed

    Berriman, J; Purnell, P; Hutchins, D A; Neild, A

    2005-02-01

    This paper describes the use of non-contact ultrasound for the evaluation of concrete. Micromachined capacitance transducers are used to transmit ultrasonic longitudinal chirp signals through concrete samples using air as the coupling medium, and a pulse compression technique is then employed for measurement of time of flight through the sample. The effect on the ultrasonic wave speed of storing concrete samples, made with the same water/cement ratio, at different humidity levels is investigated. It is shown that there is a correlation between humidity and speed of sound, allowing a correction factor for humidity to be derived. A strong positive linear correlation between aggregate content and speed of sound was then observed; there was no obvious correlation between compressive strength and speed of sound. The results from the non-contact system are compared with that from a contact system, and conclusions drawn concerning coupling of energy into the samples. PMID:15567195

  14. Transfer Factors for Contaminant Uptake by Fruit and Nut Trees

    SciTech Connect

    Napier, Bruce A.; Fellows, Robert J.; Minc, Leah D.

    2013-11-20

    Transfer of radionuclides from soils into plants is one of the key mechanisms for long-term contamination of the human food chain. Nearly all computer models that address soil-to-plant uptake of radionuclides use empirically-derived transfer factors to address this process. Essentially all available soil-to-plant transfer factors are based on measurements in annual crops. Because very few measurements are available for tree fruits, samples were taken of alfalfa and oats and the stems, leaves, and fruits and nuts of almond, apple, apricot, carob, fig, grape, nectarine, pecan, pistachio (natural and grafted), and pomegranate, along with local surface soil. The samples were dried, ground, weighed, and analyzed for trace constituents through a combination of induction-coupled plasma mass spectrometry and instrumental neutron activation analysis for a wide range of naturally-occurring elements. Analysis results are presented and converted to soil-to-plant transfer factors. These are compared to commonly used and internationally recommended values. Those determined for annual crops are very similar to commonly-used values; those determined for tree fruits show interesting differences. Most macro- and micronutrients are slightly reduced in fruits; non-essential elements are reduced further. These findings may be used in existing computer models and may allow development of tree-fruit-specific transfer models.

  15. Aggregate Exposure and Cumulative Risk Assessment--Integrating Occupational and Non-occupational Risk Factors.

    PubMed

    Lentz, T J; Dotson, G S; Williams, P R D; Maier, A; Gadagbui, B; Pandalai, S P; Lamba, A; Hearl, F; Mumtaz, M

    2015-01-01

    Occupational exposure limits have traditionally focused on preventing morbidity and mortality arising from inhalation exposures to individual chemical stressors in the workplace. While central to occupational risk assessment, occupational exposure limits have limited application as a refined disease prevention tool because they do not account for all of the complexities of the work and non-occupational environments and are based on varying health endpoints. To be of greater utility, occupational exposure limits and other risk management tools could integrate broader consideration of risks from multiple exposure pathways and routes (aggregate risk) as well as the combined risk from exposure to both chemical and non-chemical stressors, within and beyond the workplace, including the possibility that such exposures may cause interactions or modify the toxic effects observed (cumulative risk). Although still at a rudimentary stage in many cases, a variety of methods and tools have been developed or are being used in allied risk assessment fields to incorporate such considerations in the risk assessment process. These approaches, which are collectively referred to as cumulative risk assessment, have potential to be adapted or modified for occupational scenarios and provide a tangible path forward for occupational risk assessment. Accounting for complex exposures in the workplace and the broader risks faced by the individual also requires a more complete consideration of the composite effects of occupational and non-occupational risk factors to fully assess and manage worker health problems. Barriers to integrating these different factors remain, but new and ongoing community-based and worker health-related initiatives may provide mechanisms for identifying and integrating risk from aggregate exposures and cumulative risks from all relevant sources, be they occupational or non-occupational. PMID:26583907

  16. Aggregate Exposure and Cumulative Risk Assessment—Integrating Occupational and Non-occupational Risk Factors

    PubMed Central

    Lentz, T. J.; Dotson, G. S.; Williams, P. R.D.; Maier, A.; Gadagbui, B.; Pandalai, S. P.; Lamba, A.; Hearl, F.; Mumtaz, M.

    2015-01-01

    Occupational exposure limits have traditionally focused on preventing morbidity and mortality arising from inhalation exposures to individual chemical stressors in the workplace. While central to occupational risk assessment, occupational exposure limits have limited application as a refined disease prevention tool because they do not account for all of the complexities of the work and non-occupational environments and are based on varying health endpoints. To be of greater utility, occupational exposure limits and other risk management tools could integrate broader consideration of risks from multiple exposure pathways and routes (aggregate risk) as well as the combined risk from exposure to both chemical and non-chemical stressors, within and beyond the workplace, including the possibility that such exposures may cause interactions or modify the toxic effects observed (cumulative risk). Although still at a rudimentary stage in many cases, a variety of methods and tools have been developed or are being used in allied risk assessment fields to incorporate such considerations in the risk assessment process. These approaches, which are collectively referred to as cumulative risk assessment, have potential to be adapted or modified for occupational scenarios and provide a tangible path forward for occupational risk assessment. Accounting for complex exposures in the workplace and the broader risks faced by the individual also requires a more complete consideration of the composite effects of occupational and non-occupational risk factors to fully assess and manage worker health problems. Barriers to integrating these different factors remain, but new and ongoing community-based and worker health-related initiatives may provide mechanisms for identifying and integrating risk from aggregate exposures and cumulative risks from all relevant sources, be they occupational or non-occupational. PMID:26583907

  17. Deuteron form factor measurements at low momentum transfers

    NASA Astrophysics Data System (ADS)

    Schlimme, B. S.; Achenbach, P.; Beričič, J.; Böhm, R.; Bosnar, D.; Correa, L.; Distler, M. O.; Esser, A.; Fonvieille, H.; Friščić, I.; Griffioen, K. A.; Huan, Y.; Kegel, S.; Kohl, Y.; Merkel, H.; Mihovilovič, M.; Müller, J.; Müller, U.; Pochodzalla, J.; Schoth, M.; Schulz, F.; Sfienti, C.; Širca, S.; Štajner, S.; Thiel, M.; Weber, A.

    2016-03-01

    A precise measurement of the elastic electron-deuteron scattering cross section at four-momentum transfers of 0.24 fm-1 ≤ Q ≤ 2.7 fm-1 has been performed at the Mainz Microtron. In this paper we describe the utilized experimental setup and the necessary analysis procedure to precisely determine the deuteron charge form factor from these data. Finally, the deuteron charge radius rd can be extracted from an extrapolation of that form factor to Q2 = 0.

  18. University Technology Transfer Factors as Predictors of Entrepreneurial Orientation

    ERIC Educational Resources Information Center

    Kirkman, Dorothy M.

    2011-01-01

    University technology transfer is a collaborative effort between academia and industry involving knowledge sharing and learning. Working closely with their university partners affords biotechnology firms the opportunity to successfully develop licensed inventions and gain access to novel scientific and technological discoveries. These factors may…

  19. Effects of class I heparin binding growth factor and fibronectin on platelet adhesion and aggregation

    SciTech Connect

    Greisler, H.P.; Klosak, J.J.; Steinam, S.J.; Lam, T.M.; Burgess, W.H.; Kim, D.U. )

    1990-05-01

    Fibronectin and heparin binding growth factor-type 1 have been affixed to vascular graft surfaces to enhance the attachment and the proliferation of transplanted endothelial cells, respectively. The current study examines the effect of fibronectin and heparin binding growth factor-type 1 on platelet adhesion and activation in vivo and on platelet aggregation in vitro. Expanded polytetrafluoroethylene prostheses (5 cm x 4 mm internal diameter) were treated either with fibronectin (n = 9), fibronectin/heparin/heparin binding growth factor-type 1/heparin (n = 12), or neither (n = 13) and were interposed into canine aortoiliac systems bilaterally. Autogenous radiolabeled (Indium 111 oxine, 650 microCi) platelets were injected intravenously before reestablishment of circulation. Perfusion was maintained for 30 minutes, and prostheses were removed with segments of native aorta and distal iliac arteries bilaterally. Specimens were examined for thrombus-free surface area, by gamma well counting for adherent radiolabeled platelets, and by light microscopy and transmission and scanning electron microscopic techniques. Results showed that both the fibronectin and fibronectin/heparin/heparin binding growth factor-type 1/heparin pretreated prostheses contained significantly greater numbers of platelets and adherent radioactivity than did control graft segments when normalized to their ipsilateral iliac arteries. Fibronectin/heparin/heparin binding growth factor-type 1/heparin pretreated prostheses contained 27 +/- 16 times more radioactivity per square millimeter than ipsilateral iliac arteries, fibronectin pretreated prostheses had 13 +/- 8 times more radioactivity per square millimeter than ipsilateral iliac arteries, and untreated expanded polytetrafluoroethylene had 4 +/- 3 times more radioactivity per square millimeter than ipsilateral iliac arteries.

  20. Increased Tau Phosphorylation and Aggregation in Mice Overexpressing Corticotropin-Releasing Factor

    PubMed Central

    Campbell, Shannon N.; Zhang, Cheng; Monte, Louise; Roe, Allyson D.; Rice, Kenner C.; Taché, Yvette; Masliah, Eliezer; Rissman, Robert A.

    2014-01-01

    Clinical and basic science research suggests that stress and/or changes in central stress signaling intermediates may be involved in Alzheimer’s disease (AD) pathogenesis. Although the links between stress and AD remain unsettled, data from our group and others have established that stress exposure in rodents may confer susceptibility to AD pathology by inducing hippocampal tau phosphorylation (tau-P). Work in our lab has shown that stress-induced tau-P requires activation of the type-1 corticotropin-releasing factor receptor (CRFR1). CRF overexpressing (CRF-OE) mice are a model of chronic stress that display cognitive impairment at 9–10 month of age. In this study we used 6–7 month old CRF-OE mice to examine whether sustained exposure to CRF and stress steroids would impact hippocampal tau-P and kinase activity in the presence or absence of the CRFR1-specific antagonist, R121919, given daily for 30 days. CRF-OE mice had significantly elevated tau-P compared to wild type (WT) mice at the AT8 (S202/T204), PHF-1 (S396/404), S262, and S422 sites. Treating CRF-OE mice with R121919 blocked phosphorylation at the AT8 (S202/T204) and PHF-1 (S396/404) sites, but not at the S262 and S422 sites and reduced phosphorylation of c-Jun N Terminal Kinase (JNK). Examination of hippocampal extracts from CRF-OE mice at the ultrastructural level revealed negatively stained round/globular aggregates that were positively labeled by PHF-1. These data suggest critical roles for CRF and CRFR1 in tau-P and aggregation and may have implications for the development of AD cognitive decline. PMID:25125464

  1. Factor V Activator from Daboia russelli russelli Venom Destabilizes β-Amyloid Aggregate, the Hallmark of Alzheimer Disease*

    PubMed Central

    Bhattacharjee, Payel; Bhattacharyya, Debasish

    2013-01-01

    Formation of plaque by fibrils of β-amyloid (Aβ) peptide in the brain is the characteristic feature of Alzheimer disease (AD). Inhibition of the process of aggregate formation from Aβ-monomer and destabilization of the aggregate could be useful for prevention and propagation of the disease respectively. Russell's viper venom (RVV) contains protein(s) that destabilize Aβ aggregates as revealed from the thioflavin T assay. The active component was identified as factor V activator (RVV-V). Among the possible mechanisms of destabilization, RVV-V-mediated proteolysis was ruled out from mass spectrometric data and the thioflavin T assay. The alternate hypothesis that small peptides derived from RVV-V destabilize the aggregate is better supported by experimental results. Six small peptides were synthesized using RVV-V as the template, and three unrelated peptides were synthesized to serve as controls. Destabilization of Aβ aggregate by these peptides was studied using spectrofluorometric assays, atomic force microscopy, transmission electron microscopy, and confocal microscopy. Among the peptides, CTNIF and the mixture of the six peptides were most potent in converting the aggregates to the monomeric state and thus, preventing cytotoxicity in SH-SY5Y human neuroblastoma cells. The control peptides failed to show similar effects. Moreover, some of these peptides are stable in blood for 24 h. Therefore, these venom-derived peptides offer an encouraging opportunity to prevent amyloidosis and may provide information to combat AD. PMID:23986449

  2. Homolog of the maize beta-glucosidase aggregating factor from sorghum is a jacalin-related GalNAc-specific lectin but lacks protein aggregating activity.

    PubMed

    Kittur, Farooqahmed S; Yu, Hyun Young; Bevan, David R; Esen, Asim

    2009-03-01

    Recently, we identified the maize beta-glucosidase aggregating factor (BGAF) as a jacalin-related lectin (JRL) and showed that its lectin domain is responsible for beta-glucosidase aggregation. By searching for BGAF homologs in sorghum, we identified and obtained an EST clone and determined its complete sequence. The predicted protein had the same modular structure as maize BGAF, shared 67% sequence identity with it, and revealed the presence of two potential carbohydrate-binding sites (GG...ATYLQ, site I and GG...GVVLD, site II). Maize BGAF1 is the only lectin from a class of modular JRLs containing an N-terminal dirigent and a C-terminal JRL domain, whose sugar specificity and beta-glucosidase aggregating activity have been studied in detail. We purified to homogeneity a BGAF homolog designated as SL (Sorghum lectin) from sorghum and expressed its recombinant version in Escherichia coli. The native protein had a molecular mass of 32 kD and was monomeric. Both native and recombinant SL-agglutinated rabbit erythrocytes, and inhibition assays indicated that SL is a GalNAc-specific lectin. Exchanging the GG...GVVLD motif in SL with that of maize BGAF1 (GG...GIAVT) had no effect on GalNAc-binding, whereas binding to Man was abolished. Substitution of Thr(293) and Gln(296) in site I to corresponding residues (Val(294) and Asp(297)) of maize BGAF1 resulted in the loss of GalNAc-binding, indicating that site I is responsible for generating GalNAc specificity in SL. Gel-shift and pull-down assays after incubating SL with maize and sorghum beta-glucosidases showed no evidence of interaction nor were any SL-protein complexes detected in sorghum tissue extracts, suggesting that the sorghum homolog does not participate in protein-protein interactions. PMID:19056785

  3. Axial form factor of the nucleon at large momentum transfers

    NASA Astrophysics Data System (ADS)

    Anikin, I. V.; Braun, V. M.; Offen, N.

    2016-08-01

    Motivated by the emerging possibilities to study threshold pion electroproduction at large momentum transfers at Jefferson Laboratory following the 12 GeV upgrade, we provide a short theory summary and an estimate of the nucleon axial form factor for large virtualities in the Q2=1 - 10 GeV2 range using next-to-leading-order light-cone sum rules.

  4. Two cell surface proteins bind the sponge Microciona prolifera aggregation factor.

    PubMed

    Varner, J A; Burger, M M; Kaufman, J F

    1988-06-15

    Two extracellular matrix cell surface proteins which bind the proteoglycan-like aggregation factor from the marine sponge Microciona prolifera (MAF) and which may function as physiological receptors for MAF were identified and characterized for the first time. By probing nitrocellulose blots of nonreducing sodium dodecyl sulfate gels containing whole sponge cell protein with iodinated MAF, a 210- and a 68-kDa protein, which have native molecular masses of approximately 200-400 and 70 kDa, were identified. MAF binding to blots is species-specific. It is also sensitive to reduction and is completely abolished by pretreatment of live cells with proteases, as was cellular aggregation, indicating that the 210- and 68-kDa proteins may be located on the cell surface. The additional observations that the 68 kDa is an endoglycosidase F-sensitive glycoprotein and that antisera against whole sponge cells or membranes can immunoprecipitate the 210 kDa when prebound to intact cells are consistent with a cell surface location. Both proteins can be isolated from sponge cell membranes and from the sponge skeleton (insoluble extracellular matrix), but the 210-kDa MAF-binding protein can also be found in the soluble extracellular matrix (buffer washes of cells and skeleton) as well. A third MAF-binding protein of molecular mass 95 kDa was also found in the sponge extracellular matrix but rarely on cells. Both of the cell-associated 210- and 68-kDa proteins are nonintegral membrane proteins, based on Triton X-114 phase separation, flotation of liposomes containing sponge membrane lysates, and their extraction from membranes by buffer washes. Both proteins bind MAF affinity resins, indicating that they each exhibit a moderate affinity for MAF under native conditions. They can also be separated from each other and from the bulk of the protein in an octylpolyoxyethylene extract of membranes by fast protein liquid chromatography Mono Q anion exchange chromatography, as assessed by native

  5. Geologic and societal factors affecting the international oceanic transport of aggregate

    USGS Publications Warehouse

    Langer, W.H.

    1995-01-01

    Crushed stone and sand and gravel are the two main sources of natural aggregate, and together comprise approximately half the volume and tonnage of mined material in the United States. Natural aggregate is a bulky, heavy material without special or unique properties, and it is commonly used near its source of production to minimize haulage cost. However, remoteness is no longer an absolute disqualifier for the production of aggregate. Today interstate aggregate routinely is shipped hundreds of kilometers by rail and barge. In addition, during 1992, the United States imported 1,317,000 metric tons of aggregate from Canada and 1,531,000 metric tons from Mexico. A number of ports on the Atlantic Coast and Gulf Coast of the United States receive imports of crushed stone from foreign sources for transport to various parts of the eastern United States. These areas either lack adequate supplies of aggregate or are augmenting their supplies because they have difficulties meeting current demand. These difficulties may include poor stone quality, environmental permitting problems, or transportation. Certain societal and geologic conditions of New York City and Philadelphia along the Atlantic Coast, and Tampa and New Orleans along the Gulf Coast, are discussed to demonstrate the different combinations of issues that contribute to the economic viability of importing crushed stone. ?? 1995 Oxford University Press.

  6. Chlorophyll a Franck-Condon factors and excitation energy transfer

    SciTech Connect

    Pieper, J. ||; Voigt, J.; Small, G.J. |

    1999-04-01

    The Franck-Condon factors for the S{sub 1}(Q{sub y}) {leftrightarrow} S{sub 0} electronic transition of chlorophyll (Chl) molecules are important for understanding excitation energy transfer in photosynthetic complexes. Currently, there are two sets of Chl a Frank-Condon factors for over 40 modes, one determined by spectral hole burning and the other by fluorescence line narrowing. Those obtained by the latter spectroscopy are, on average, a factor of 30 times smaller than the hole burning values. Nonline-narrowed fluorescence results for the light-harvesting complex 2 of photosystem 2 at 4.2 K are presented that agree quite well with the hole burning but not the fluorescence line narrowing values.

  7. Studies on Resistance Transfer Factor Deoxyribonucleic Acid in Escherichia coli

    PubMed Central

    Silver, Richard P.; Falkow, Stanley

    1970-01-01

    A variant of the derepressed R factor, R1, which does not contain any of the drug resistance markers, and represents, in large part, the resistance transfer factor (RTF) was studied in Escherichia coli. RTF deoxyribonucleic acid (DNA) was specifically labeled in a female cell after conjugation. Physical characterization of the molecule showed that RTF possessed an average molecular weight of 50 × 106 daltons and a buoyant density of 1.709 g/cm3. By comparison to R1, we calculate that the region of DNA carrying the drug resistance genes is therefore about 20% of the R1 molecule and has a buoyant density of approximately 1.716 g/cm3. These results support the hypothesis that the single species of R-factor DNA observed in E. coli represents a composite of the 1.709 and 1.716 g/cm3 replicons seen in Proteus. PMID:4919749

  8. Effects of extraction methods and factors on leaching of metals from recycled concrete aggregates.

    PubMed

    Bestgen, Janile O; Cetin, Bora; Tanyu, Burak F

    2016-07-01

    Leaching of metals (calcium (Ca), chromium (Cr), copper, (Cu), iron (Fe), and zinc (Zn)) of recycled concrete aggregates (RCAs) were investigated with four different leachate extraction methods (batch water leach tests (WLTs), toxicity leaching procedure test (TCLP), synthetic precipitation leaching procedure test (SPLP), and pH-dependent leach tests). WLTs were also used to perform a parametric study to evaluate factors including (i) effects of reaction time, (ii) atmosphere, (iii) liquid-to-solid (L/S) ratio, and (iv) particle size of RCA. The results from WLTs showed that reaction time and exposure to atmosphere had impact on leaching behavior of metals. An increase in L/S ratio decreased the effluent pH and all metal concentrations. Particle size of the RCA had impact on some metals but not all. Comparison of the leached concentrations of metals from select RCA samples with WLT method to leached concentrations from TCLP and SPLP methods revealed significant differences. For the same RCA samples, the highest metal concentrations were obtained with TCLP method, followed by WLT and SPLP methods. However, in all tests, the concentrations of all four (Cr, Cu, Fe, and Zn) metals were below the regulatory limits determined by EPA MCLs in all tests with few exceptions. pH-dependent batch water leach tests revealed that leaching pattern for Ca is more cationic whereas for other metals showed more amphoteric. The results obtained from the pH-dependent tests were evaluated with geochemical modeling (MINTEQA2) to estimate the governing leaching mechanisms for different metals. The results indicated that the releases of the elements were solubility-controlled except Cr. PMID:26996910

  9. Aggregation of Minnesota water-use data and transfer of data to the National Water-Use Data System; procedures and programs

    USGS Publications Warehouse

    Trotta, L.C.

    1988-01-01

    The Minnesota Water-Use Data System stores data on the quantity of withdrawals and discharge in Minnesota. To transfer these data into the U.S. Geological Survey 's National Water-Use Data System properly, certain procedures must be followed. Uniform data categorization and entry allows comparison of water use from State to State. The data in the National Water-Use Data System are aggregated by county and by watershed (hydrologic unit). This report documents the data aggregation and transfer process as developed by the Minnesota Department of Natural Resources, the Minnesota State Planning Agency/Planning Information Center, and the U.S. Geological Survey as part of the National Water-Use Information Program. (USGS)

  10. On the nature of canopy illumination due to differences in elemental orientation and aggregation for radiative transfer

    NASA Astrophysics Data System (ADS)

    Govind, Ajit

    2014-10-01

    The nature of canopy radiative transfer mechanism (CRTM) describes the amount of beam penetration through a canopy and governs the nature of canopy illumination, i.e. the abundance of sunlit and shaded portions. Realistic representation of canopy illumination is critical for simulating various canopy biophysical processes associated with vegetated land surfaces. The adequate representation of CRTM can be attributed to the parameterizations of the two main canopy characteristics: the foliage projection (G-function) and the clumping effect (Ω function). Herein, using various types of G and Ω functions developed in a previous study, I tested 15 CRTM scenarios that combine different types of G and Ω functions to predict the dynamics of sunlit fraction (ɛ) of canopies having a wide range of plant area index (Ptotal) at various solar zenith angles (SZAs). It was observed that, for a given Ptotal, ɛ decreases as the SZA increases. However, ɛ significantly changed in accordance with the type of G and Ω functions used. Scenarios that employed random distribution of elements in space (S-4, S-9, and S-14) consistently returned larger ɛ values even at lower SZAs. This means that ignoring the clumping behavior of canopies could result in greater proportion of sunlit elements thereby reducing the beam penetration deeper into the canopy as opposed to those canopies where the elements are more aggregated. Beyond 70° SZA, almost all the scenarios returned similar ɛ values for a given Ptotal, which implied that the methods used is less sensitive at higher SZAs. The values of ɛ calculated by all the scenarios were significantly different from the S-6 (the ideal case). This observation highlights the importance of explicitly describing the G and Ω functions to adequately depict canopy illumination conditions.

  11. Effects of ion aggregation on the intervalence transfer band of the mixed-valence biferrocenium cation in solution

    SciTech Connect

    Lowery, M.D.; Hammack, W.S.; Drickamer, H.G.; Hendrickson, D.N.

    1987-12-23

    The concentration dependence of the energy (E/sup op/) of the intervalence transfer (IT) electronic absorption band of mixed-valence biferrocenium triiodide dissolved in either nitrobenzene or dichloromethane is examined. In nitrobenzene, E/sup op/ increases rapidly from approx. 5.57 to approx. 6.05 x 10/sup 3/ cm/sup -1/ in the 0.24-0.4 mM range, whereupon further increases in the concentration of biferrocenium triiodide lead to E/sup op/ increasing more gradually to a value approx. 6.3 x 10/sup 3/ cm/sup -1/ at 24 mM. On the other hand, the full width at half maximum (..delta.. anti v/sub 1/2) and the transition moment of the IT band decrease with increasing concentration for biferrocenium triiodide in nitrobenzene. E/sup op/ increases, ..delta.. anti v/sub 1/2 remains constant, and the transition moment of the IT band increases with increasing concentration for biferrocenium triiodide in dichloromethane in the more limited range of 0.30-0.95 mM. These concentration dependencies of the IT band for biferrocenium triiodide are attributable to variable degrees of ion aggregation in solution. The concentration dependencies of the electrical conductivity of solutions of biferrocenium triiodide in either nitrobenzene or dichloromethane substantiate this proposal. IT band contours obtained at different concentrations are fit to the PKS vibronic model to yield parameters that characterize the electronic and vibronic coupling within the mixed-valence biferrocenium cation.

  12. Soil type as factor controlling the effects of forest transformation to agricultural use in soil aggregation and related properties

    NASA Astrophysics Data System (ADS)

    Chrenková, Katarína; Mataix-Solera, Jorge; Dlapa, Pavel; Arcenegui, Victoria

    2014-05-01

    The stability of aggregates has an important role in soil functioning and its behavior to avoid erosion and degradation, the ability to transfer liquids and gases, which are important features for crop production and ecosystem health (Tisdall and Oades, 1982). It's also a property that is highly influenced by land use and management (Angers et al., 1993). The stability of aggregates provides key information about the capacity of soil functions that defines the soil quality. This study has aimed to identify the long-term effects of forest transformation on agricultural use on soil structure and related properties. For the research was chosen seven localities in the Alicante Province (E Spain) with different soil types in all cases to compare how the land use changes can affect as a function of soil type and characteristics. In every site, samples were collected from agricultural land use (dry crops with tillage management), and in forest areas close to them with similar soil type that are used as references. On the samples, selected physical and chemical properties were analyzed such as Soil aggregate stability (AS), Organic matter (OM), Mean weight diameter (MWD) of aggregates and Water repellency (WR). As expected, in all cases the AS was significant lower in agricultural sites than in forest. But in some cases the differences were much higher than in others. In forest sites the AS varied between 46 to 82% while in agricultural sites ranged between 14 to 45%. The results showed strong positive correlation of AS with OM. The lowest initial values of AS were found in wettable sandy soils. The agricultural land use lead to relative decrease in AS by 39 to 79% compared to forest soils, indicating that some soils are much more vulnerable to land use than others. These differences can be explained mainly because intrinsic soil properties, such as OM content, texture, and WR. Particularly, the decrease in OM content and absence of WR are responsible for the decrease in

  13. Preparation and properties of the specific anti-influenza virus transfer factor

    PubMed Central

    2010-01-01

    Specific anti-influenza virus and normal transfer factors prepared in an experimental animal model, the pig, have been tested for their components, characteristics, and activity of known specificity. Two transfer factors are small molecular mixture which consist entirely or partly of polypeptides and polynucleosides. Moreover, the biological activity of transfer factors could be approved by Rosettes test and specific skin test. The study would lay a foundation for the research and development of other specific transfer factor. PMID:20836866

  14. Quantitative analysis of intrinsic and extrinsic factors in the aggregation mechanism of Alzheimer-associated Aβ-peptide

    PubMed Central

    Meisl, Georg; Yang, Xiaoting; Frohm, Birgitta; Knowles, Tuomas P. J.; Linse, Sara

    2016-01-01

    Disease related mutations and environmental factors are key determinants of the aggregation mechanism of the amyloid-β peptide implicated in Alzheimer's disease. Here we present an approach to investigate these factors through acquisition of highly reproducible data and global kinetic analysis to determine the mechanistic influence of intrinsic and extrinsic factors on the Aβ aggregation network. This allows us to translate the shift in macroscopic aggregation behaviour into effects on the individual underlying microscopic steps. We apply this work-flow to the disease-associated Aβ42-A2V variant, and to a variation in pH as examples of an intrinsic and an extrinsic perturbation. In both cases, our data reveal a shift towards a mechanism in which a larger fraction of the reactive flux goes via a pathway that generates potentially toxic oligomeric species in a fibril-catalyzed reaction. This is in agreement with the finding that Aβ42-A2V leads to early-onset Alzheimer’s disease and enhances neurotoxicity. PMID:26758487

  15. HEALTH AND ENVIRONMENTAL SCIENCES INSTITUTE'S EXPOSURE FACTORS DATABASE FOR AGGREGATE AND CUMULATIVE RISK ASSESSMENT

    EPA Science Inventory

    In recent years, the risk analysis community has broadened its use of complex aggregate and cumulative residential exposure models (e.g., to meet the requirements of the 1996 Food Quality Protection Act). The value of these models is their ability to incorporate a range of input...

  16. Environmental factors affecting twitching motility, biofilm development, and aggregation by Xylella fastidiosa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The bacterial pathogen Xylella fastidiosa causes many important plant diseases in different crops such as citrus, grapes, almond and coffee. While disease symptoms expressed by this pathogen are not completely understood, it is widely accepted that blockage of xylem vessels by aggregates of the bact...

  17. Aggregation of adverse behaviors and its affecting factors among young military conscripts in Taiwan.

    PubMed

    Wu, Der-Min; Chu, Nain-Feng; Lin, Yaoh-Shiang; Lai, Hsiang-Ru

    2007-06-01

    The authors studied the prevalence of the aggregation in common lifestyle habits, namely, cigarette smoking, alcohol drinking, and betel-nut chewing and the demographic correlates of individual aggregation in these lifestyle behaviors among young military conscripts in Taiwan. Cross-sectional screening was conducted among conscripts in southern and eastern sections of Taiwan from Aug. 1st to Dec. 31st 2001. Totally, 3913 conscripts who had more than 1 month of service were included in this multistage sampling study. Information on smoking, drinking, and betel-nut chewing habits were ascertained as part of a self-administered questionnaire completed by examinees at the service unit. Aggregation in lifestyle habits was studied by comparing the observed and expected proportions (O/E ratio) with their 95% confidence intervals (CI) for zero, one, two, and three simultaneously occurring lifestyle habits. The study results showed a significant clustering of lifestyle habits studied; the number of subjects was greater than expected in groups with two (for cigarette smoking and betel-nut chewing, O/E ratio=1.17, 95%CI=1.06-1.28), and three (O/E ratio=5.63, 95%CI=5.06-6.20) lifestyle habits. Determinants for this clustering of lifestyle habits included lower educational levels and residential area in southern and eastern sections of Taiwan. There was a significant individual aggregation in lifestyle habits including cigarette smoking, alcohol drinking, and betel-nut chewing in the health survey among young military conscripts. In addition, young military conscripts with low educational levels and residential area in southern and eastern sections of Taiwan had an apparent tendency toward the aggregation in these lifestyle habits. PMID:17107751

  18. Influence of risk behavior aggregation in different categories of physical activity on the occurrence of cardiovascular risk factors

    PubMed Central

    2013-01-01

    Background We aimed to verify the association of risk behavior aggregation in different categories of physical activity (PA) with the presence of cardiovascular risk factors (RF) employees at a public university. Method We analyzed data of 376 employees, which were visited in their workplace for measurement of weight, height and questionnaires to identify the risk behaviors and risk factors. Chi-square test was used to analyze the association between the dependent and independent variables and binary logistic regression was used to construct a multivariate model for the observed associations. Results Associations were found between the aggregation of following risk behaviors: smoking, alcohol consumption and physical inactivity, considered in different categories of PA, and the increase in RF, except for the presence of hypertriglyceridemia. Individuals with two or more risk behaviors in occupational PA category are more likely to be hypertensive (3.04 times) and diabetes (3.44 times). For the free time PA category, these individuals were 3.18 times more likely to have hypercholesterolemia and for locomotion PA, more likely to be hypertensive (2.42 times) and obese (2.51 times). Conclusion There are association between the aggregation of two or more risk behaviors and the presence of cardiovascular RF. PMID:23800219

  19. AIDS and transfer factor: myths, certainties and realities.

    PubMed

    Viza, D

    1996-01-01

    At the end of the 20th century, the triumph of biology is as indisputable as that of physics was at the end of the 19th century, and so is the might of the inductive thought. Virtually all diseases have been seemingly conquered and HIV, the cause of AIDS, has been fully described ten years after the onset of the epidemic. However, the triumph of biological science is far from being complete. The toll of several diseases, such as cancer, continues to rise and the pathogenesis of AIDS remains elusive. In the realm of inductive science, the dominant paradigm can seldom be challenged in a frontal attack, especially when it is apparently successful, and only what Kuhn calls "scientific revolutions" can overthrow it. Thus, it is hardly surprising that the concept of transfer factor is considered with contempt, and the existence of the moiety improbable: over forty years after the introduction of the concept, not only its molecular structure remains unknown, but also its putative mode of action contravenes dogmas of both immunology and molecular biology. And when facts challenge established dogmas, be in religion, philosophy or science, they must be suppressed. Thus, results of heterodox research become henceforth nisi-i.e., valid unless cause is shown for rescinding them, because they challenge the prevalent paradigm. However, when observations pertain to lethal disorders, their suppression in the name of dogmas may become criminal. Because of the failure of medical science to manage the AIDS pandemic, transfer factor, which has been successfully used for treating or preventing viral infections, may today overcome a priori prejudice and rejection more swiftly. In science, as in life, certainties always end up by dying, and Copernicus' vision by replacing that of Ptolemy. PMID:8993753

  20. Soil-to-crop transfer factors of tellurium.

    PubMed

    Yang, Guosheng; Zheng, Jian; Tagami, Keiko; Uchida, Shigeo

    2014-09-01

    Stable tellurium (Te) concentrations in 148 sets of agricultural soil and associated crop samples were measured in this study to obtain soil-to-crop transfer factor (TF) of Te. We used a recently developed simple method that applies digestion of samples with aqua regia and sector field inductively coupled plasma mass spectrometry to measure low Te levels in these samples. Geometric mean (GM) concentrations of Te in soil and crops were 75μgkg(-1)-dry (range: 15-850μgkg(-1)-dry) and 1.8μgkg(-1)-dry (range: 0.1-120μgkg(-1)-dry), respectively; the Te concentration range was significantly wider in crops than in soil. Using these data, we calculated TFs and obtained their range from 1.3×10(-3) to 1.1×10(-1). The GM of TF for upland field crops was calculated to be 2.0×10(-2) and for brown rice was 3.1×10(-2); all crop types had the similar GMs of their TF values. Data comparison for TF of Te was carried out with six elements, which are present in anionic forms in soil environment like Te is, i.e. P, Br, As, Se, Mo, and I. TFs of Te and I showed the highest correlation factor for upland field crops by t-test (r=0.577, p<0.001), but no correlation was found for brown rice. We considered it likely that different water management practices in upland fields and paddy fields affected the Te transfer from soil to crops. PMID:24997965

  1. A study of estrogen metabolic clearance rates and transfer factors

    PubMed Central

    Hembree, W. C.; Bardin, C. W.; Lipsett, M. B.

    1969-01-01

    We have attempted to measure the metabolic clearance rates (MCR) and the transfer factors of estradiol (E2) and estrone (E1) during 2-hr and 12-hr infusions. When estradiol-3H was infused for 2 hr, apparent equilibrium was reached at 70 min; the 12-hr infusions showed that plasma estradiol-3H levels increased slowly throughout the infusion. When estrone-3H was infused, constancy of estrone-3H levels was not attained in either the 2-hr infusions or in the two 12-hr infusions. The tritium level in the metabolite of the infused estrogen did not become constant in 50% of the short infusions and increased during all the long infusions. Thus, the conversion ratios CE1E2 and CE2E1 continually changed and transfer factors could not be calculated. The apparent “MCR'S” calculated on the basis of the 2-hr studies expressed as liters/24 hr per m2 ±SD were: “MCRE1” (women) 980 ±94, (men) 1170 ±95; “MCRE2” (women) 615 ±17, (men) 830 ±30. The estradiol “MCR's” differed significantly between men and women. “MCRE2” was the same using either estradiol-14C or -3H and was unchanged by the infusion of 170 μg of estradiol daily. Postmenopausal women had estrogen “MCR's” in the same range as premenopausal women. Excess glucocorticoids increased the “MCRE2.” PMID:5822587

  2. Initial solidification phenomena: Factors affecting heat transfer in strip casting

    NASA Astrophysics Data System (ADS)

    Nolli, Paolo

    In the last few years a few companies have announced the final stage of the commercial development of strip casting of steels. In strip casting heat extraction and productivity are limited by the thermal resistance at the interface between processed material and moving mold (rolls for twin-roll strip casters). Among many factors influencing interfacial heat transfer, films of various composition, either formed during casting or deposited before casting on the surface of the rolls, melt superheat and gas atmosphere composition can have a significantly positive or negative effect on the achieved heat transfer rate. From an industrial point view, methods to improve interfacial heat transfer rates must be found, in order to increase productivity. The objective of this research project is to assess if it is feasible to improve heat transfer rates during solidification of steel in direct contact with a copper mold: (1) by the application of thin coatings on the mold surface; (2) by adding a reactive gas species containing sulfur in the gas shrouding where casting is performed. To address the former, solidification experiments were performed with the mold surface either kept uncoated or coated with coatings of different compositions. To address the latter, the experiments were performed in gas shrouding atmospheres with or without sulphydric acid. It was observed that the resulting heat extraction rates were improved by the application of certain coatings and by the addition of H2S to the gas atmosphere. These findings prove that the application of coatings and the use of small amounts of reactive gaseous species containing sulfur may be methods to increase productivity in strip casting. The effect of superheat and the effect of naturally deposited oxides (Mn-oxide) were also evaluated experimentally. A numerical study of the effect of the critical undercooling on the productivity of a twin-roll strip caster showed that the maximum allowable casting speed can be increased

  3. PM4 crystalline silica emission factors and ambient concentrations at aggregate-producing sources in California.

    PubMed

    Richards, John R; Brozell, Todd T; Rea, Charles; Boraston, Geoff; Hayden, John

    2009-11-01

    The California Construction and Industrial Minerals Association and the National Stone, Sand, & Gravel Association have sponsored tests at three sand and gravel plants in California to compile crystalline silica emission factors for particulate matter (PM) of aerodynamic diameter of 4 microm or less (PM4) and ambient concentration data. This information is needed by industrial facilities to evaluate compliance with the Chronic Reference Exposure Level (REL) for ambient crystalline silica adopted in 2005 by the California Office of Environmental Health Hazard Assessment. The REL applies to PM4 respirable PM. Air Control Techniques, P.C. sampled for PM4 crystalline silica using a conventional sampler for PM of aerodynamic diameter of 2.5 microm or less (PM2.5), which met the requirements of 40 Code of Federal Regulations Part 50, Appendix L. The sample flow rate was adjusted to modify the 50% cut size to 4 microm instead of 2.5 microm. The filter was also changed to allow for crystalline silica analyses using National Institute for Occupational Safety and Health (NIOSH) Method 7500. The particle size-capture efficiency curve for the modified Appendix L instrument closely matched the performance curve of NIOSH Method 0600 for PM4 crystalline silica and provided a minimum detection limit well below the levels attainable with NIOSH Method 0600. The results of the tests indicate that PM4 crystalline silica emissions range from 0.000006 to 0.000110 lb/t for screening operations, tertiary crushers, and conveyor transfer points. The PM4 crystalline silica emission factors were proportional to the crystalline silica content of the material handled in the process equipment. Measured ambient concentrations ranged from 0 (below detectable limit) to 2.8 microg/m3. All values measured above 2 microg/m3 were at locations upwind of the facilities being tested. The ambient PM4 crystalline silica concentrations measured during this study were below the California REL of 3 microg/m3

  4. Reduction in aggregation and energy transfer of quantum dots incorporated in polystyrene beads by kinetic entrapment due to cross-linking during polymerization.

    PubMed

    Vaidya, Shyam V; Couzis, Alex; Maldarelli, Charles

    2015-03-17

    We report the development of barcoded polystyrene microbeads, approximately 50 μm in diameter, which are encoded by incorporating multicolored semiconductor fluorescent nanocrystals (quantum dots or QDs) within the microbeads and using the emission spectrum of the embedded QDs as a spectral label. The polymer/nanocrystal bead composites are formed by polymerizing emulsified liquid droplets of styrene monomer and QDs suspended in an immiscible continuous phase (suspension polymerization). We focus specifically on the effect of divinylbenzene (DVB) added to cross-link the linearly growing styrene polymer chains and the effect of this cross-linking on the state of aggregation of the nanocrystals in the composite. Aggregated states of multicolor QDs give rise to nonradiative resonance energy transfer (RET) which distorts the emission label from a spectrum recorded in a reference solvent in which the nanocrystals are well dispersed and unaggregated. A simple barcode is chosen of a mixture of QDs emitting at 560 (yellow) and 620 nm (red). We find that for linear chain growth (no DVB), the QDs aggregate as is evident from the emission spectrum and the QD distribution as seen from confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM) images. Increasing the extent of cross-linking by the addition of DVB is shown to significantly decrease the aggregation and provide a clear label. We suggest that in the absence of cross-linking, linearly growing polymer chains, through enthalpic and entropic effects, drive the nanocrystals into inclusions, while cross-linking kinetically entraps the particle and prevents their aggregation. PMID:25674811

  5. Platelet-activating factor mediates the cytotoxicity induced by W7FW14F apomyoglobin amyloid aggregates in neuroblastoma cells.

    PubMed

    Sirangelo, Ivana; Giovane, Alfonso; Maritato, Rosa; D'Onofrio, Nunzia; Iannuzzi, Clara; Giordano, Antonio; Irace, Gaetano; Balestrieri, Maria Luisa

    2014-12-01

    W7FW14F apomyoglobin (W7FW14F ApoMb) amyloid aggregates induce cytotoxicity in SH-SY5Y human neuroblastoma cells through a mechanism not fully elucidated. Amyloid neurotoxicity process involves calcium dyshomeostasis and reactive oxygen species (ROS) production. Another key mediator of the amyloid neurotoxicity is Platelet-Activating Factor (PAF), an inflammatory phospholipid implicated in neurodegenerative diseases. Here, with the aim at evaluating the possible involvement of PAF signaling in the W7FW14F ApoMb-induced cytotoxicity, we show that the presence of CV3899, a PAF receptor (PAF-R) antagonist, prevented the detrimental effect of W7FW14F ApoMb aggregates on SH-SY5Y cell viability. Noticeably, we found that the activation of PAF signaling, following treatment with W7FW14F ApoMb, involves a decreased expression of the PAF acetylhydroase II (PAF-AH II). Interestingly, the reduced PAF-AH II expression was associated with a decreased acetylhydrolase (AH) activity and to an increased sphingosine-transacetylase activity (TA(S)) with production of N-acetylsphingosine (C2-ceramide), a well known mediator of neuronal caspase-dependent apoptosis. These findings suggest that an altered PAF catabolism takes part to the molecular events leading to W7FW14F ApoMb amyloid aggregates-induced cell death. PMID:25053109

  6. Uptake and transfer factors of 137Cs by mushrooms.

    PubMed

    Heinrich, G

    1992-01-01

    The 137Cs content of 118 species (668 samples) of higher fungi collected in the period from August 1984 to October 1989 at three different locations in Styria, Austria, was determined by gamma-spectrometry. The Cs-content of most mushrooms has been increasing since September 1986. In order to find out which factors determine the 137Cs-contamination of mushrooms and the transfer-value soil to mushroom, the concentration of total and plant-available radiocesium in soils as well as the pH-value, the content of humus, clay, silt, sand, exchangeable cations, the composition of the clay minerals, and the particle size distribution of the soils of two different locations were examined. The higher the 137Cs contamination of the soil, the thicker the layer of humus and the higher the content of humus, the lower the pH-value, and the lower the amount of essential cations, especially of K+, the higher the amount of 137Cs plant-available will be. Therefore, the contamination of the mushrooms in the coniferous forest of Koralpenblick (1000 m) is higher than in the mixed forest at the Rosenberg around Graz at approx. 500 m height. Of 26 different species of mushrooms measured at both sites, only 61% show the highest TF-values soil to mushrooms also at the Koralpenblick. In the spruce forest at Koralpenblick there are many species of mushrooms with high 137Cs-contamination which were not found at the Rosenberg. However, the properties of the species to which a mushroom belongs are more important than environmental conditions and soil properties. The transfer values of 40K stay within narrow bounds, whereas those of 137Cs differ widely. PMID:1589573

  7. Different Factors Affecting Human ANP Amyloid Aggregation and Their Implications in Congestive Heart Failure

    PubMed Central

    Millucci, Lia; Paccagnini, Eugenio; Ghezzi, Lorenzo; Bernardini, Giulia; Braconi, Daniela; Laschi, Marcella; Consumi, Marco; Spreafico, Adriano; Tanganelli, Piero; Lupetti, Pietro; Magnani, Agnese; Santucci, Annalisa

    2011-01-01

    Aims Atrial Natriuretic Peptide (ANP)-containing amyloid is frequently found in the elderly heart. No data exist regarding ANP aggregation process and its link to pathologies. Our aims were: i) to experimentally prove the presumptive association of Congestive Heart Failure (CHF) and Isolated Atrial Amyloidosis (IAA); ii) to characterize ANP aggregation, thereby elucidating IAA implication in the CHF pathogenesis. Methods and Results A significant prevalence (85%) of IAA was immunohistochemically proven ex vivo in biopsies from CHF patients. We investigated in vitro (using Congo Red, Thioflavin T, SDS-PAGE, transmission electron microscopy, infrared spectroscopy) ANP fibrillogenesis, starting from α-ANP as well as the ability of dimeric β-ANP to promote amyloid formation. Different conditions were adopted, including those reproducing β-ANP prevalence in CHF. Our results defined the uncommon rapidity of α-ANP self-assembly at acidic pH supporting the hypothesis that such aggregates constitute the onset of a fibrillization process subsequently proceeding at physiological pH. Interestingly, CHF-like conditions induced the production of the most stable and time-resistant ANP fibrils suggesting that CHF affected people may be prone to develop IAA. Conclusions We established a link between IAA and CHF by ex vivo examination and assessed that β-ANP is, in vitro, the seed of ANP fibrils. Our results indicate that β-ANP plays a crucial role in ANP amyloid deposition under physiopathological CHF conditions. Overall, our findings indicate that early IAA-related ANP deposition may occur in CHF and suggest that these latter patients should be monitored for the development of cardiac amyloidosis. PMID:21814559

  8. Kinetic study of the aggregation and lipid mixing produced by alpha-sarcin on phosphatidylglycerol and phosphatidylserine vesicles: stopped-flow light scattering and fluorescence energy transfer measurements.

    PubMed Central

    Mancheño, J. M.; Gasset, M.; Lacadena, J.; Ramón, F.; Martínez del Pozo, A.; Oñaderra, M.; Gavilanes, J. G.

    1994-01-01

    alpha-Sarcin is a fungal cytotoxic protein that inactivates the eukaryotic ribosomes. A kinetic study of the aggregation and lipid mixing promoted by this protein on phosphatidylglycerol (PG) and phosphatidylserine (PS) vesicles has been performed. Egg yolk PG, bovine brain PS, dimyristoyl-PG (DMPG) and dimyristoyl-PS (DMPS) vesicles have been considered. The initial rates of the vesicle aggregation induced by the protein have been measured by stopped-flow 90 degrees light scattering. The formation of a vesicle dimer as the initial step of this process was deduced from the second-order dependence of the initial rates on phospholipid concentration. The highest alpha-sarcin concentration studied did not inhibit the vesicle aggregation, indicating that many protein molecules are involved in the vesicle cross-linking. These are common characteristics of the initial steps of the aggregation produced by alpha-sarcin in the four types of phospholipid vesicles considered. However, the kinetics of the scattering values revealed that more complex changes occurred in the later steps of the aggregation process of egg PG and brain PS vesicles than in those of their synthetic counterparts. alpha-Sarcin produced lipid mixing in vesicles composed of DMPG or DMPS, which was measured by fluorescence resonance energy transfer assays. A delay in the onset of the process, dependent on the protein concentration, was observed. Measurement of the rates of lipid mixing revealed that the process is first order on phospholipid concentration. Egg PG and brain PS vesicles did not show lipid mixing, although they avidly aggregated. However, alpha-sarcin was able to promote lipid mixing in heterogeneous systems composed of egg PG+DMPG or brain PS+DMPS vesicles. The dilution of the fluorescence probes was faster when these were incorporated into the bilayers made of synthetic phospholipids than were present in those made of natural phospholipids. The bilayer destabilization produced by the

  9. Effects of stress and other environmental factors on horizontal plasmid transfer assessed by direct quantification of discrete transfer events.

    PubMed

    Johnsen, Anders R; Kroer, Niels

    2007-03-01

    Selection pressure may affect the horizontal transfer of plasmids. The inability to distinguish between gene transfer and the growth of transconjugants complicates testing. We have developed a method that enables the quantification of discrete transfer events. It uses large numbers of replicate matings (192 or 384) in microtiter wells and the counting of transfer-positive and transfer-negative wells. We applied the method to study the transfer of the IncP1 plasmid pRO103 between Escherichia coli and Pseudomonas putida strains. pRO103 encodes resistance to mercury and tetracycline and partial degradation of 2,4-dichlorophenoxyacetic acid (2,4-D). The results showed positive correlation between transfer and donor metabolic activity, and an optimal temperature for transfer of 29 degrees C. On stimulation of donor activity, the optimal temperature was decreased to 24.5 degrees C. HgCl(2) above 1.0 microg L(-1) negatively affected transfer, whereas 2,4-D up to 0.3 mM had no effect. The negative effect of mercury was shown to be a result of stressing of the recipient. No effects of mercury on transfer could be detected by traditional filter mating. Thus, the method is superior to filter mating and, as the experimental design allows the manipulation of individual parameters, it is ideal for the assessment and comparison of effects of environmental factors on plasmid transfer. PMID:17100984

  10. Standardisation of gas mixtures for estimating carbon monoxide transfer factor.

    PubMed Central

    Kendrick, A. H.; Laszlo, G.

    1993-01-01

    BACKGROUND--The American Thoracic Society recommends that the inspired concentration used for the estimation of carbon monoxide transfer factor (TLCO) mixture should be 0.25-0.35% carbon monoxide, 10-14% helium, 17-21% oxygen, balance nitrogen. Inspired oxygen influences alveolar oxygen and hence carbon monoxide uptake, such that transfer factor increases by 0.35% per mm Hg decrease in alveolar oxygen. To aid in the standardisation of TLCO either a known inspired oxygen concentration should be used, or TLCO should be corrected to a standard inspired oxygen concentration. The range of gas mixtures used in practice and the implications for cost and accuracy have been investigated. METHODS--A questionnaire was sent to 185 respiratory units in the UK requesting information on (1) the method used to estimate TLCO, (2) the manufacturer of the equipment, (3) the mixture used, (4) whether "medical quality" gas was ordered, and (5) the level of satisfaction with supplier service. RESULTS--Replies were received from 106 units. Most used the single breath breath holding method for which 17 different test mixtures were ordered. One unit also used the single breath exhalation method. Inspired oxygen ranged from 17.94% to 25%, giving a wide variation in alveolar oxygen and hence TLCO. Forty seven units ordered a specific inspired oxygen, the rest ordering "air" as balance. The cost per litre of gas varied greatly, with the mixture 14% helium, 0.28% carbon monoxide, balance air (17.9% oxygen) and 10% helium, 0.28% carbon monoxide, balance air (18.8% oxygen) being cheapest to produce. Ordering a specific inspired oxygen concentration increased the cost. Large cylinders of gas were cheaper for the same mixture. The mixture for the exhalation method was the most expensive. Sixty seven units ordered "medical quality" gas and six assumed this was supplied. Twenty nine (27%) were dissatisfied with their supplier due to (1) poor service, (2) long delivery times, (3) costs, or (4

  11. Differences in factors influencing the familial aggregation of febrile convulsion in population and hospital patients.

    PubMed

    Tsai, J J; Huang, M C; Lung, F W; Huang, C C; Change, Y C

    1996-11-01

    Socio-demographic data, initial clinical manifestations, outcome and family aggregation of febrile convulsion (FC) were compared between 85 population and 364 multicenter patients. More patients presented with clustering of seizures and had recurrence of FC in multicenter group than in population group. Multicenter patients had more fever episodes per year, more day-card attendance and a higher incidence of FC history in their parents. The odds ratio of FC in the siblings was 6:1 in population group and 12:1 in multicenter group. Lower socioeconomic status influenced the presence of FC in the sibling of population group. Instead, FC histories in the father and paternal cousins of probands had influence on the presence of FC in the siblings of multicenter group. We conclude that the population FC sample rather than the hospital sample is the more representative. And there are differences not only in the clinical manifestations but also in the effect of environmental and genetic influences on the family aggregation in population and hospital patients. PMID:8947282

  12. Factors Differentiating Hospital Transfers from Long-term Care Facilities with High and Low Transfer Rates.

    ERIC Educational Resources Information Center

    Teresi, Jeanne A.; And Others

    1991-01-01

    Examined differences among nursing homes in rates at which they transfer patients to hospitals. Data from nursing staff and charts on 286 most recent transfers from 10 nursing homes revealed that, from relatively equivalent patient populations, high-rate facilities transferred more chronically ill, physically frail patients and patients with…

  13. Sub-Nanosecond Resonance Energy Transfer in the Near-Infrared within Self-Assembled Conjugates of PbS Quantum Dots and Cyanine Dye J-Aggregates.

    PubMed

    Wang, Chen; Weiss, Emily A

    2016-08-01

    Energy transfer (EnT) of near-infrared (NIR) excitons enables applications in harvesting of solar energy and biological imaging. Fast exciton extraction from NIR-absorbing Pb-chalcogenide quantum dots (QDs) may allow utilization of the photon downconversion (multiple exciton generation) process that occurs in those QDs to amplify signal in QD-based sensors or photocurrent in QD-based photovoltaics. This paper describes subnanosecond extraction of NIR excitons from PbS QDs by adsorbed J-aggregates of cyanine dye in aqueous dispersions. The QD/J-aggregate complexes form through electrostatic self-assembly, and the rate and yield of EnT within the complexes can be optimized by adjusting spectral overlap between QD emission and the J-aggregate absorption, which are controlled by density of charged ligands on the QD surface and the pH. The primary EnT pathways have rate constants ranging from (800 ps)(-1) to (2.2 ns)(-1), which are 1-2 orders of magnitude faster than previously reported examples with PbS QDs as exciton donors. The fastest EnT process occurs in 90 ps and is potentially competitive with Auger recombination of biexcitonic states in PbS QDs. PMID:27359272

  14. General and specific factors in the intersensory transfer of form.

    NASA Technical Reports Server (NTRS)

    Clark, J. L.; Warm, J. S.; Schumsky, D. A.

    1972-01-01

    This study assessed the relative contributions of specific and nonspecific components to intersensory transfer between vision and touch. A paired-associate paradigm was used in which visual metric figures and their tactual analogs served as stimuli, and familiar adjectives were the responses. Positive intersensory transfer, characterized by symmetry across modalities was obtained. The contribution of nonspecific learning to this effect was negligible. Intersensory transfer was found to be less efficient than the empirically determined maximum level of intrasensory transfer possible in this task.

  15. Influence of the Valine Zipper Region on the Structure and Aggregation of the Basic Leucine Zipper (bZIP) Domain of Activating Transcription Factor 5 (ATF5)

    PubMed Central

    Ciaccio, Natalie A.; Reynolds, T. Steele; Middaugh, C. Russell; Laurence, Jennifer S.

    2012-01-01

    Protein aggregation is a major problem for biopharmaceuticals. While the control of aggregation is critically important for the future of protein pharmaceuticals, mechanisms of aggregate assembly, particularly the role that structure plays, are still poorly understood. Increasing evidence indicates that partially folded intermediates critically influence the aggregation pathway. We have previously reported the use of the basic leucine zipper (bZIP) domain of Activating Transcription Factor 5 (ATF5) as a partially folded model system to investigate protein aggregation. This domain contains three regions with differing structural propensity: a N-terminal polybasic region, a central helical leucine zipper region, and a C-terminal extended valine zipper region. Additionally, a centrally positioned cysteine residue readily forms an intermolecular disulfide bond that reduces aggregation. Computational analysis of ATF5 predicts that the valine zipper region facilitates self-association. Here we test this hypothesis using a truncated mutant lacking the C-terminal valine zipper region. We compare the structure and aggregation of this mutant to the wild-type (WT) form under both reducing and non-reducing conditions. Our data indicate that removal of this region results in a loss of alpha-helical structure in the leucine zipper and a change in the mechanism of self-association. The mutant form displays increased association at low temperature but improved resistance to thermally induced aggregation. PMID:23067245

  16. Spatial and seasonal factors are key determinants in the aggregation of helminths in their definitive hosts: Pseudamphistomum truncatum in otters (Lutra lutra).

    PubMed

    Sherrard-Smith, E; Perkins, S E; Chadwick, E A; Cable, J

    2015-01-01

    Parasites are typically aggregated within their host populations. The most heavily infected hosts are frequently cited as targets for optimal disease control. Yet a heavily infected individual is not necessarily highly infective and does not automatically contribute a higher proportion of infective parasitic stages than a host with fewer parasites. Here, Pseudamphistomum truncatum (Opisthorchiida) parasitic infection within the definitive otter host (Lutra lutra) is used as a model system. The hypothesis tested is that variation in parasite abundance, aggregation and egg production (fecundity, as a proxy of host infectivity) can be explained by abiotic (season and region) or biotic (host age, sex and body condition) factors. Parasite abundance was affected most strongly by the biotic factors of age and body condition, such that adults and otters with a higher condition index had heavier infections than sub-adults or those with a lower condition index, whilst there were no significant differences in parasite abundance among the seasons, regions (ecological regions defined by river catchment boundaries) or host sexes. Conversely, parasite aggregation was affected most strongly by the abiotic factors of season and region, which were supported by four different measures of parasite aggregation (the corrected moment estimate k, Taylor's Power Law, the Index of Discrepancy D, and Boulinier's J). Pseudamphistomum truncatum was highly aggregated within otters, with aggregation stronger in the Midlands (England) and Wales than in the southwestern region of the United Kingdom. Overall, more parasites were found in fewer hosts during the summer, which coincides with the summer peak in parasite fecundity. Combined, these data suggest that (i) few otters carry the majority of P. truncatum parasites and that there are more infective stages (eggs) produced during summer; and (ii) abiotic factors are most influential when describing parasite aggregation whilst biotic factors have

  17. Student Perceptions of Factors Contributing to Community-College-to-University Transfer Success

    ERIC Educational Resources Information Center

    Gard, Dwight R.; Paton, Valerie; Gosselin, Kevin

    2012-01-01

    The transfer process includes areas such as academic preparation and advisement, transfer evaluation, financial aid, and psychosocial factors. A descriptive, exploratory method was employed to capture the perceptions of a transfer student cohort regarding their experiences in transitioning from lower division community college enrollment to…

  18. Factors in the Transfer of Governance-Facilitation Skills within Farmers' Marketing Organizations in Uganda

    ERIC Educational Resources Information Center

    Miiro, Richard F.; Mazur, Robert E.; Matsiko, Frank B.

    2012-01-01

    Purpose: Training transfer has been examined for formal industrial and service organizations in developed countries but rarely for rural organizations in sub-Saharan Africa. This study sought to identify transfer system factors that best explain the transfer of governance-facilitation skills provided to leaders of farmers' marketing organizations…

  19. Antiplatelet aggregation and platelet activating factor (PAF) receptor antagonistic activities of the essential oils of five Goniothalamus species.

    PubMed

    Moharam, Bushra Abdulkarim; Jantan, Ibrahim; Ahmad, Fasihuddin bin; Jalil, Juriyati

    2010-08-01

    Nine essential oils, hydrodistilled from different parts of five Goniothalamus species (G. velutinus Airy-Shaw, G. woodii Merr., G. clemensii Ban, G. tapis Miq. and G. tapisoides Mat Salleh) were evaluated for their ability to inhibit platelet aggregation in human whole blood using an electrical impedance method and their inhibitory effects on platelet activating factor (PAF) receptor binding with rabbit platelets using 3H-PAF as a ligand. The chemical composition of the oils was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The bark oil of G. velutinus was the most effective sample as it inhibited both arachidonic acid (AA) and ADP-induced platelet aggregation with IC(50) values of 93.6 and 87.7 microg/mL, respectively. Among the studied oils, the bark oils of G. clemensii, G. woodii, G. velutinus and the root oil of G. tapis showed significant inhibitory effects on PAF receptor binding, with IC(50 )values ranging from 3.5 to 10.5 microg/mL. The strong PAF antagonistic activity of the active oils is related to their high contents of sesquiterpenes and sesquiterpenoids, and the individual components in the oils could possibly produce a synergistic effect in the overall antiplatelet activity of the oils. PMID:20714290

  20. High Quality Factor Resonators for Inductive Power Transfer Systems

    NASA Astrophysics Data System (ADS)

    Etemadrezaei, Mohammad

    In this dissertation, the Inductive Power Transfer (IPT) systems for multi-MHz frequency of operation are investigated, and new ideas for magnetic link inductive coils are presented. (Abstract shortened by ProQuest.).

  1. Platelet aggregation values in patients with cardiovascular risk factors are reduced by verbascoside treatment. A randomized study.

    PubMed

    Campo, Gianluca; Pavasini, Rita; Biscaglia, Simone; Ferri, Alessandra; Andrenacci, Elisa; Tebaldi, Matteo; Ferrari, Roberto

    2015-07-01

    Verbascoside, a phenolic compound, showed several favorable biological activities, including an antiplatelet activity. No in vivo studies tested its efficacy and safety in subjects with cardiovascular (CV) factors. The aim of this randomized, single-center, double-blind, phase II study was to assess the efficacy and tolerability of verbascoside intake for the modulation of platelet aggregation (PA) values in subjects with cardiovascular (CV) risk factors. One-hundred subjects with at least one CV risk factor (age >65 years, diabetes mellitus, hypertension, current cigarettes use, hyperlidemia, waist circumference >102 cm in male or >88 cm in female) were enrolled and randomly assigned to receive placebo or verbascoside 50mg or verbascoside 100mg. PA was measured at baseline and after 2 weeks of study drug assumption, with light transmittance aggregometry (arachidonic acid, AA, 1 μM and adenosine diphosphate, ADP, 5 μM). Two weeks of treatment with placebo or verbascoside 50mg did not modify PA values (both after AA and ADP stimuli). On the contrary, after 2 weeks of verbascoside 100mg, PA values decreased significantly (from 51 ± 13% to 39 ± 15%, p<0.01 after AA; from 60 ± 12% to 49 ± 15%, p = 0.01 after ADP). No serious adverse events were reported during the study, and no subjects discontinued the study because of adverse events. We conclude that long-term intake of verbascoside 100mg significantly reduces PA values in subjects with CV risk factors. PMID:25846253

  2. Abiotic factors in colony formation: effects of nutrition and light on extracellular polysaccharide production and cell aggregates of Microcystis aeruginosa

    NASA Astrophysics Data System (ADS)

    Yang, Zhen; Kong, Fanxiang

    2013-07-01

    Colony morphology is important for Microcystis to sustain a competitive advantage in eutrophic lakes. The mechanism of colony formation in Microcystis is currently unclear. Extracellular polysaccharide (EPS) has been reported to play an important role in cell aggregate formation of some phytoplankton. Microcystis aeruginosa was cultivated under varied abiotic conditions, including different nutrient, light, and temperature conditions, to investigate their effects on EPS production and morphological change. The results show that nutrient concentration and light intensity have great effects on EPS productionin M. aeruginosa. There was a considerable increase in EPS production after M. aeruginosa was cultivated in adjusted culture conditions similar to those present in the field (28.9 mg C/L, 1.98 mg N/L, 0.65 mg P/L, light intensity: 100 μmol/(m2 · s)). These results indicate that abiotic factors might be one of the triggers for colony formation in Microcystis.

  3. Ratiometric fluorescent ion detection in water with high sensitivity via aggregation-mediated fluorescence resonance energy transfer using a conjugated polyelectrolyte as an optical platform.

    PubMed

    Le, Van Sang; Kim, Boram; Lee, Wonho; Jeong, Ji-Eun; Yang, Renqiang; Woo, Han Young

    2013-05-14

    A cationic conjugated polyelectrolyte was designed and synthesized based on poly(fluorene-co-phenylene) containing 5 mol% benzothiadiazole (BT) as a low energy trap and 15-crown-5 as a recognizing group for potassium ions. A potassium ion can form a sandwich-type 2:1 Lewis acid-based complex with 15-crown-5, to cause the intermolecular aggregation of polymers. This facilitates inter-chain fluorescence resonance energy transfer (FRET) to a low-energy BT segment, resulting in fluorescent signal amplification, even at dilute analyte concentrations. Highly sensitive and selective detection of K(+) ions was demonstrated in water. The linear response of ratiometric fluorescent signal as a function of [K(+) ] allows K(+) quantification in a range of nanomolar concentrations with a detection limit of ≈0.7 × 10(-9) M. PMID:23417971

  4. The growth factor inhibitor suramin reduces apoptosis and cell aggregation in protein-free CHO cell batch cultures.

    PubMed

    Zanghi, J A; Renner, W A; Bailey, J E; Fussenegger, M

    2000-01-01

    We have previously shown that Chinese hamster ovary (CHO) cells capable of growing in medium free of exogenous proteins die by apoptosis during all stages of a batch culture (Zanghi et al., 1999). On the basis of the hypothesis that extracellular death factors might be important in apoptosis under these conditions, we examined the effect of the growth factor inhibitor and antitumor agent suramin on CHO cell growth and apoptosis in serum-free culture. Suramin protected against apoptosis during exponential growth, as indicated by the absence of DNA laddering and an increase in cell viability from roughly 70% to above 95%. Suramin also effectively dispersed cell aggregates so that single-cell suspension culture was possible. However, suramin did not protect against apoptosis during the death phase, in contrast to serum, suggesting that antiapoptotic factors in the serum remain to be discovered. The increased viable cell yield following suramin supplementation resulted in a 40% increase in product yield, based on results with cells expressing recombinant secreted alkaline phosphatase. Polysulfated compounds dextran sulfate and polyvinyl sulfate worked nearly as well as suramin in dispersing cell clumps and increasing viable cell yield, which implies that suramin's high sulfate group density may be responsible for its effects in cell culture. In addition, suramin was beneficial for long-term adaptation of CHO cells to protein-free media suspension culture, and the compound was synergistic with insulin in accelerating this adaptation time. PMID:10835230

  5. Factors Affecting the Development of Somatic Cell Nuclear Transfer Embryos in Cattle

    PubMed Central

    AKAGI, Satoshi; MATSUKAWA, Kazutsugu; TAKAHASHI, Seiya

    2014-01-01

    Nuclear transfer is a complex multistep procedure that includes oocyte maturation, cell cycle synchronization of donor cells, enucleation, cell fusion, oocyte activation and embryo culture. Therefore, many factors are believed to contribute to the success of embryo development following nuclear transfer. Numerous attempts to improve cloning efficiency have been conducted since the birth of the first sheep by somatic cell nuclear transfer. However, the efficiency of somatic cell cloning has remained low, and applications have been limited. In this review, we discuss some of the factors that affect the developmental ability of somatic cell nuclear transfer embryos in cattle. PMID:25341701

  6. Functional roles of aggregation-promoting-like factor in stress tolerance and adherence of Lactobacillus acidophilus NCFM.

    PubMed

    Goh, Yong Jun; Klaenhammer, Todd R

    2010-08-01

    Aggregation-promoting factors (Apf) are secreted proteins that have been associated with a diverse number of functional roles in lactobacilli, including self-aggregation, the bridging of conjugal pairs, coaggregation with other commensal or pathogenic bacteria, and maintenance of cell shape. In silico genome analysis of Lactobacillus acidophilus NCFM identified LBA0493 as a 696-bp apf gene that encodes a putative 21-kDa Apf protein. Transcriptional studies of NCFM during growth in milk showed apf to be one of the most highly upregulated genes in the genome. In the present study, reverse transcriptase-quantitative PCR (RT-QPCR) analysis revealed that the apf gene was highly induced during the stationary phase compared to that during the logarithmic phase. To investigate the functional role of Apf in NCFM, an Delta apf deletion mutant was constructed. The resulting Delta apf mutant, NCK2033, did not show a significant difference in cell morphology or growth compared to that of the NCFMDelta upp reference strain, NCK1909. The autoaggregation phenotype of NCK2033 in planktonic culture was unaffected. Additional phenotypic assays revealed that NCK2033 was more susceptible to treatments with oxgall bile and sodium dodecyl sulfate (SDS). Survival rates of NCK2033 decreased when stationary-phase cells were exposed to simulated small-intestinal and gastric juices. Furthermore, NCK2033 in the stationary phase showed a reduction of in vitro adherence to Caco-2 intestinal epithelial cells, mucin glycoproteins, and fibronectin. The data suggest that the Apf-like proteins may contribute to the survival of L. acidophilus during transit through the digestive tract and, potentially, participate in the interactions with the host intestinal mucosa. PMID:20562289

  7. Soil-to-plant transfer factors for radiocesium and radiostrontium in agricultural systems

    SciTech Connect

    Nisbet, A.F.; Woodman, R.F.M.

    2000-03-01

    A database of soil-to-plant transfer factors for radiocesium and radiostrontium has been compiled for arable crops from published and unpublished sources. The database is more extensive than previous compilations of data published by the International Union of Radioecologists, containing new information for Scandinavia and Greece in particular. It also contains ancillary data on important soil characteristics. The database is sub-divided into 28 soil-crop combinations, covering four soil types and seven crop groups. Statistical analyses showed that transfer factors for radiocesium could not generally be predicted as a function of climatic region, type of experiment, age of contamination, or silt characteristics. However, significant relationships accounting for more than 30% of the variability in transfer factor were identified between transfer factors for radiostrontium and soil pH/organic matter status for a few soil-crop combinations. Best estimate transfer factors for radiocesium and radiostrontium were calculated for 28 soil-crop combinations, based on their geometric means: only the edible parts were considered. To predict the likely value of future individual transfer factors, 95% confidence intervals were also derived. A comparison of best estimate transfer factors derived in this study with recommended values published by the International Union of Radioecologists in 1989 and 1992 was made for comparable soil-crop groupings. While there were no significant differences between the best estimate values derived in this study and the 1992 data, radiological assessments that still use 1989 data may be unnecessarily cautious.

  8. Analytical heat transfer of a porous media: An analysis of the thermal characteristics of synthetic lightweight aggregate

    NASA Astrophysics Data System (ADS)

    Hellickson, Timothy H.

    The thermal insulative properties of a sustainable concrete-based aggregate infused with recycling waste plus fly-ash are investigated to define the effective thermal conductivity based upon optimal volume ratio of the constituent materials. The complex structures were characterized with the use of metallographic sectioning and image processing by exploiting the information given by the gradient of the color held within the image. Next, a tri-skeleton mesh was mapped over the image and a finite element analysis was conducted. The output of the finite element analysis was the temperature contour and an integrated flux over each surface from which the effective thermal conductivity of the material could be calculated via Fourier's Law. The development of a new methodology that evaluates the effective thermal conductivity for a conductivity ratio of less than 10 and a volume density of 0.60 was developed based upon the material properties, the microscopic geometry and a non-interaction approximation. Lastly, the results of the thermal test were used validate the finite element program.

  9. von Willebrand factor fibers promote cancer-associated platelet aggregation in malignant melanoma of mice and humans.

    PubMed

    Bauer, Alexander T; Suckau, Jan; Frank, Kathrin; Desch, Anna; Goertz, Lukas; Wagner, Andreas H; Hecker, Markus; Goerge, Tobias; Umansky, Ludmila; Beckhove, Philipp; Utikal, Jochen; Gorzelanny, Christian; Diaz-Valdes, Nancy; Umansky, Viktor; Schneider, Stefan W

    2015-05-14

    Tumor-mediated procoagulatory activity leads to venous thromboembolism and supports metastasis in cancer patients. A prerequisite for metastasis formation is the interaction of cancer cells with endothelial cells (ECs) followed by their extravasation. Although it is known that activation of ECs and the release of the procoagulatory protein von Willebrand factor (VWF) is essential for malignancy, the underlying mechanisms remain poorly understood. We hypothesized that VWF fibers in tumor vessels promote tumor-associated thromboembolism and metastasis. Using in vitro settings, mouse models, and human tumor samples, we showed that melanoma cells activate ECs followed by the luminal release of VWF fibers and platelet aggregation in tumor microvessels. Analysis of human blood samples and tumor tissue revealed that a promoted VWF release combined with a local inhibition of proteolytic activity and protein expression of ADAMTS13 (a disintegrin-like and metalloproteinase with thrombospondin type I repeats 13) accounts for this procoagulatory milieu. Blocking endothelial cell activation by the low-molecular-weight heparin tinzaparin was accompanied by a lack of VWF networks and inhibited tumor progression in a transgenic mouse model. Our findings implicate a mechanism wherein tumor-derived vascular endothelial growth factor-A (VEGF-A) promotes tumor progression and angiogenesis. Thus, targeting EC activation envisions new therapeutic strategies attenuating tumor-related angiogenesis and coagulation. PMID:25977583

  10. The Influence of Transfer System Factors and Training Elapsed Time on Transfer in a Healthcare Organization

    ERIC Educational Resources Information Center

    Mihalko, Beverly J.

    2010-01-01

    Organizations and other sponsors of training face increasing pressure to demonstrate the value or impact of their training programs on individual and organizational performance. A critical element in the validation of training effectiveness is the permanent transfer of learned knowledge, skills, and behaviors to the workplace. The generalization…

  11. Relation of pulmonary vessel size to transfer factor in subjects with airflow obstruction

    SciTech Connect

    Musk, A.W.

    1983-11-01

    In a group of 61 consecutive patients undergoing assessment of airflow obstruction, a significant linear relation was demonstrated between measurements of the diameter of the midzonal pulmonary vessels on the plain chest radiographs and transfer factor (diffusing capacity for carbon monoxide) (r = 0.46, p < 0.001). Since reduction in transfer factor has been shown to relate to structural emphysema, reduction in midzone vessel caliber implies the same. However, in the individual patient neither the transfer factor nor structural emphysema can be reliably predicted from midzone vessel diameters alone.

  12. PSYCHOLOGICAL AND EDUCATIONAL FACTORS IN TRANSFER OF TRAINING, PHASE I. FINAL REPORT.

    ERIC Educational Resources Information Center

    STOLUROW, LAWRENCE M.

    A FINAL REPORT WAS MADE OF THE ACTIVITIES PURSUED IN PHASE 1 OF A 10-YEAR PROJECT DEALING WITH THE PSYCHOLOGICAL AND EDUCATIONAL FACTORS INVOLVED IN TRANSFER OF TRAINING. PHASE I CONSISTED OF A SURVEY OF THE EXISTENT DATA AND CONCEPTS OF TRANSFER OF TRAINING IN AN ATTEMPT (1) TO SUMMARIZE, INTEGRATE, CONSOLIDATE, AND INTERPRET RESEARCH FINDINGS…

  13. Perception of Transfer Climate Factors in the Macro and Micro Organizational Work Environment

    ERIC Educational Resources Information Center

    Diggs, Byron Kenneth

    2011-01-01

    This qualitative study was designed to provide insight on the perceived transfer climate factors in the macro and micro organizational work environment that may influence an employee's willingness to transfer what was learned in a training program to the job. More specifically, the purpose of the study was to delineate descriptive patterns and…

  14. An Extracellular Serine/Threonine-Rich Protein from Lactobacillus plantarum NCIMB 8826 Is a Novel Aggregation-Promoting Factor with Affinity to Mucin

    PubMed Central

    Hevia, Arancha; Martínez, Noelia; Ladero, Víctor; Álvarez, Miguel A.; Margolles, Abelardo

    2013-01-01

    Autoaggregation in lactic acid bacteria is directly related to the production of certain extracellular proteins, notably, aggregation-promoting factors (APFs). Production of aggregation-promoting factors confers beneficial traits to probiotic-producing strains, contributing to their fitness for the intestinal environment. Furthermore, coaggregation with pathogens has been proposed to be a beneficial mechanism in probiotic lactic acid bacteria. This mechanism would limit attachment of the pathogen to the gut mucosa, favoring its removal by the human immune system. In the present paper, we have characterized a novel aggregation-promoting factor in Lactobacillus plantarum. A mutant with a knockout of the D1 gene showed loss of its autoaggregative phenotype and a decreased ability to bind to mucin, indicating an adhesion role of this protein. In addition, heterologous production of the D1 protein or an internal fragment of the protein, characterized by its abundance in serine/threonine, strongly induced autoaggregation in Lactococcus lactis. This result strongly suggested that this internal fragment is responsible for the bioactivity of D1 as an APF. To our knowledge, this is the first report on a gene coding for an aggregation-promoting factor in Lb. plantarum. PMID:23892754

  15. Simulation of a Wireless Power Transfer System for Electric Vehicles with Power Factor Correction

    SciTech Connect

    Pickelsimer, Michael C; Tolbert, Leon M; Ozpineci, Burak; Miller, John M

    2012-01-01

    Wireless power transfer has been a popular topic of recent research. Most research has been done to address the limitations of coil-to-coil efficiency. However, little has been done to address the problem associated with the low input power factor with which the systems operate. This paper details the steps taken to analyze a wireless power transfer system from the view of the power grid under a variety of loading conditions with and without power factor correction.

  16. Transforming growth factor-beta 1 stimulates synthesis of proteoglycan aggregates in calf articular cartilage organ cultures

    SciTech Connect

    Morales, T.I. )

    1991-04-01

    Previous work showed that transforming growth factor-beta 1 (TGF-beta 1), added alone to bovine cartilage organ cultures, stimulated (35S)sulfate incorporation into macromolecular material but did not investigate the fidelity of the stimulated system to maintain synthesis of cartilage-type proteoglycans. This paper provides evidence that chondrocytes synthesize the appropriate proteoglycan matrix under TGF-beta 1 stimulation: (1) there is a coordinated increase in hyaluronic acid and proteoglycan monomer synthesis, (2) link-stable proteoglycan aggregates are assembled, (3) the hybrid chondroitin sulfate/keratan sulfate monomeric species is synthesized, and (4) there is an increase in protein core synthesis. Some variation in glycosylation patterns was observed when proteoglycans synthesized under TGF-beta 1 stimulation were compared to those synthesized under basal conditions. Thus comparing TGF-beta 1 to basal samples respectively, the monomers were larger (Kav on Sepharose CL-2B = 0.29 vs 0.41), the chondroitin sulfate chains were longer by approximately 3.5 kDa, the percentage of total glycosaminoglycan in keratan sulfate increased slightly from approximately 4% (basal) to approximately 6%, and the unsulfated disaccharide decreased from 28% (basal) to 12%. All of these variations are in the direction of a more anionic proteoglycan. Since the ability of proteoglycans to confer resiliency to the cartilage matrix is directly related to their anionic nature, these changes would presumably have a beneficial effect on tissue function.

  17. An antagonistic activity of etizolam on platelet-activating factor (PAF). In vitro effects on platelet aggregation and PAF receptor binding.

    PubMed

    Mikashima, H; Takehara, S; Muramoto, Y; Khomaru, T; Terasawa, M; Tahara, T; Maruyama, Y

    1987-08-01

    The antagonistic effect of etizolam, an anti-anxiety drug, on platelet-activating factor (PAF) was investigated in rabbit platelets in vitro. Etizolam inhibited PAF-induced aggregation in a dose-dependent manner, with an IC50 of 3.8 microM, about one tenth that of triazolam (IC50 = 30 microM). At 300 microM, it inhibited both ADP and arachidonic acid-induced aggregation only slightly, while the other anti-anxiety drugs tested had no effect on PAF-induced aggregation even at this concentration. Etizolam and triazolam inhibited the specific binding of 3H-PAF to PAF receptor sites on washed rabbit platelets with IC50 values of 22 nM and 320 nM, respectively. Diazepam and estazolam were inactive even at 1 microM. These results indicate that etizolam is a specific antagonist of PAF. PMID:2890779

  18. Factors affecting the efficiency of embryo transfer in the domestic ferret (Mustela putorius furo).

    PubMed

    Li, Ziyi; Sun, Xingshen; Chen, Juan; Leno, Gregory H; Engelhardt, John F

    2006-07-15

    Embryo transfer (ET) to recipient females is a foundational strategy for a number of assisted reproductive technologies, including cloning by somatic cell nuclear transfer. In an attempt to develop efficient ET in domestic ferrets, factors affecting development of transferred embryo were investigated. Unilateral and bilateral transfer of zygotes or blastocysts in the oviduct or uterus was evaluated in recipient nulliparous or primiparous females. Developing fetuses were collected from recipient animals 21 days post-copulation and examined. The percentage of fetal formation was different (P<0.05) for unilateral and bilateral transfer of zygotes (71%) in nulliparous females with bilateral transfer (56%) in primiparous recipients. The percentage (90%) of fetal formation in nulliparous recipients following unilateral transfer of blastocysts was higher (P<0.05) than that observed in primiparous recipients with bilateral ET (73%). Notably, the percentage of fetal formation was higher (P<0.05) when blastocyts were transferred as compared to zygotes (90% versus 71%). Transuterine migration of embryos occurred following all unilateral transfers and also in approximately 50% of bilateral transfers with different number of embryos in each uterine horn. These data will help to facilitate the development of assisted reproductive strategies in the ferret and could lead to the use of this species for modeling human disease and for conservation of the endangered Mustelidae species such as black-footed ferret and European mink. PMID:16330092

  19. Family Aggregation and Risk Factors in Phobic Disorders over Three-Generations in a Nation-Wide Study

    PubMed Central

    Steinhausen, Hans-Christoph; Jakobsen, Helle; Meyer, Andrea; Jørgensen, Povl Munk; Lieb, Roselind

    2016-01-01

    evidence for the family aggregation and further risk factors in PHO. In contrast to anxiety disorders and other major mental disorders the family load of PHO in this nation-wide study was rather low. PMID:26785257

  20. Impact of Particle Aggregation on Nanoparticle Reactivity

    NASA Astrophysics Data System (ADS)

    Jassby, David

    2011-12-01

    The prevalence of nanoparticles in the environment is expected to grow in the coming years due to their increasing pervasiveness in consumer and industrial applications. Once released into the environment, nanoparticles encounter conditions of pH, salinity, UV light, and other solution conditions that may alter their surface characteristics and lead to aggregation. The unique properties that make nanoparticles desirable are a direct consequence of their size and increased surface area. Therefore, it is critical to recognize how aggregation alters the reactive properties of nanomaterials, if we wish to understand how these properties are going to behave once released into the environment. The size and structure of nanoparticle aggregates depend on surrounding conditions, including hydrodynamic ones. Depending on these conditions, aggregates can be large or small, tightly packed or loosely bound. Characterizing and measuring these changes to aggregate morphology is important to understanding the impact of aggregation on nanoparticle reactive properties. Examples of decreased reactivity due to aggregation include the case where tightly packed aggregates have fewer available surface sites compared to loosely packed ones; also, photocatalytic particles embedded in the center of large aggregates will experience less light when compared to particles embedded in small aggregates. However, aggregation also results in an increase in solid-solid interfaces between nanoparticles. This can result in increased energy transfer between neighboring particles, surface passivation, and altered surface tension. These phenomena can lead to an increase in reactivity. The goal of this thesis is to examine the impacts of aggregation on the reactivity of a select group of nanomaterials. Additionally, we examined how aggregation impacts the removal efficiency of fullerene nanoparticles using membrane filtration. The materials we selected to study include ZnS---a metal chalcogenide

  1. Corticotropin-releasing factor receptor-dependent effects of repeated stress on tau phosphorylation, solubility, and aggregation

    PubMed Central

    Rissman, Robert A.; Staup, Michael A.; Lee, Allyson Roe; Justice, Nicholas J.; Rice, Kenner C.; Sawchenko, Paul E.

    2012-01-01

    Exposure and/or sensitivity to stress have been implicated as conferring risk for development of Alzheimer's disease (AD). Although the basis for such a link remains unclear, we previously reported differential involvement of corticotropin-releasing factor receptor (CRFR) 1 and 2 in acute stress-induced tau phosphorylation (tau-P) and solubility in the hippocampus. Here we examined the role of CRFRs in tau-P induced by repeated stress and the structural manifestations of altered tau solubility. Robust tau-P responses were seen in WT and CRFR2 null mice exposed to repeated stress, which were sustained at even 24 h after the final stress exposure. A portion of phosphorylated tau in these mice was sequestered in detergent-soluble cellular fractions. In contrast, CRFR1 and CRFR double-KO mice did not exhibit repeated stress-induced alterations in tau-P or solubility. Similarly, treatment with CRFR1 antagonist attenuated repeated stress-induced tau-P. Using histochemical approaches in a transgenic CRFR1 reporter mouse line, we found substantial overlap between hippocampal CRFR1 expression and cells positive for phosphorylated tau after exposure to repeated stress. Ultrastructural analysis of negatively stained extracts from WT and CRFR2 null mice identified globular aggregates that displayed positive immunogold labeling for tau-P, as well as conformational changes in tau (MC1) seen in early AD. Given that repeated stress exposure results in chronic increases in hippocampal tau-P and its sequestration in an insoluble (and potentially prepathogenic) form, our data may define a link between stress and an AD-related pathogenic mechanism. PMID:22451915

  2. Dynamic structure factor for large aggregate clusters with internal motions: a self-consistent light-scattering study on conjugated polymer solutions.

    PubMed

    Wen, Yu H; Lin, Po C; Hua, Chi C; Chen, Show A

    2011-12-15

    The aggregation properties of a standard conjugated polymer, poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV), in two distinct solvents (chloroform and toluene) and a range of polymer concentrations (c = 0.1-3 mg/mL) have been unequivocally resolved using combined dynamic and static light scatterings (DLS/SLS). The prime challenges for analyzing this peculiar, practically important, solution system arise from the wide size distribution and unknown aggregate morphology, as well as pronounced interferences between translational and internal motions of aggregate clusters of considerably varying size. To cope with these central difficulties, we propose a self-consistent formulation for analyzing the dynamic structure factor in DLS experiment by extending an existing theory on free-draining bead-spring chains that explicitly accounts for internal fluctuations, along with two candidate form factors on Gaussian coil and rigid sphere, respectively, serving as two limiting cases to be discriminated in combined DLS and SLS measurements. Given that no accessibility to ultrasmall angular resolutions is a prerequisite, the suggested protocol can readily be carried out in conventional light-scattering apparatus. The present analyses unanimously support the rigid-sphere form factor in describing the entire set of light-scattering data on MEH-PPV solutions, differing from early small-angle neutron/X-ray scattering interpretations suggesting certain 2D fractal structures for the aggregation network. Scrutiny into the interior dynamics of aggregate clusters further disclosed that the segmental motions are noticeably more suppressed than for usual, nonaggregated polymer solutions, and no existing theories based on the bead-spring picture can yet capture the observed scaling behavior as manifested by the present data. Accordingly, we report several first-revealed properties of MEH-PPV solutions on the aggregate morphology, the size distribution (and mean size

  3. Factors that influence passive transfer of immunoglobulins in foals.

    PubMed

    LeBlanc, M M; Tran, T; Baldwin, J L; Pritchard, E L

    1992-01-15

    Effects of farm management, breed, mare age, gestation duration, and climatologic factors on colostral specific gravity, colostral IgG concentration, and foal serum IgG concentration were evaluated. Climatologic variables measured were daily maximal, minimal, and mean air temperature, precipitation, average relative humidity, and total solar radiation. Presuckle, postpartum colostrum samples were collected from 140 Standardbred, 94 Thoroughbred, and 59 Arabian mares from January through June during 1985 and 1986. Thoroughbred (farm A, n = 61; farm B, n = 33) and Arabian (farm C, n = 45; farm D, n = 14) mares were located in Ocala, Fla; Standardbred mares (farm E) were in Montgomery, NY. Mares from farms A, B, D, and E foaled in box stalls, and mares from farm C foaled in sand paddocks. Mares with premature lactation greater than 12 hours were not included in the study. Foals were clinically normal at birth and suckled colostrum without assistance within 2 hours of parturition. Specific gravity of presuckle colostrum samples was measured by use of an equine colostrometer. Blood samples were collected 18 hours after parturition from 253 of the 293 foals (n = 45, 25, 32, 13, 138 on farms A through E, respectively) to determine serum concentration of IgG. The IgG concentrations in colostrum and serum were measured by single radial immunodiffusion. Data were analyzed by multiple regression or chi 2 analysis. The most important determinants of foal serum IgG concentration were the IgG content and specific gravity of presuckle colostrum samples (P less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1559872

  4. A simple parameterization for quality factor as a function of linear energy transfer

    NASA Technical Reports Server (NTRS)

    Townsend, Lawrence W.; Wilson, John; Cucinotta, Francis A.

    1987-01-01

    The paper presents a simple analytic approximation of the radiation quality factor (Q) as a function of linear energy transfer for use in radiation protection calculations. The paper also presents estimated quality factors in water for protons over a broad range of incident energies. It is shown that the quality factors are less than unity for all proton energies greater than 13 MeV.

  5. Construction aggregates

    USGS Publications Warehouse

    Tepordei, V.V.

    1995-01-01

    Part of the 1994 Industrial Minerals Review. The production, consumption, and applications of construction aggregates are reviewed. In 1994, the production of construction aggregates, which includes crushed stone and construction sand and gravel combined, increased 7.7 percent to 2.14 Gt compared with the previous year. These record production levels are mostly a result of funding for highway construction work provided by the Intermodal Surface Transportation Efficiency Act of 1991. Demand is expected to increase for construction aggregates in 1995.

  6. [Production of a dialysable transfer factor of cell mediated immunity by lymphoblastoid cells in continuous proliferation].

    PubMed

    Goust, J M; Viza, D; Moulias, R; Trejdosiewicz, L; Lesourd, B; Marescot, M R; Prévot, A

    1975-01-20

    Four lymphoblastoid cell lines tested in this work contain normally a dialysable moiety having by ultraviolet spectroscopy, column chromatography (Biogel P 10) and chemically the same properties than human dialysable Transfer Factor (TFd), but unable to transfer cell mediated immune response against common antigens. Two of them are able to do so after incubation with minimal amounts of TFd. Production of a molecule identical to human TFd is possible in some lymphoblastoid cell lines after induction with TFd. PMID:808340

  7. Factors affecting transfer of polycyclic aromatic hydrocarbons from made tea to tea infusion.

    PubMed

    Lin, Daohui; Zhu, Lizhong; Luo, Lan

    2006-06-14

    Factors affecting transfer percentages of 12 polycyclic aromatic hydrocarbons (PAHs) were investigated, including tea variety, tea/water ratio (TWR, g/mL), brewing times, washed tea or unwashed tea, and covered cup or uncovered cup. It was observed that %PAH transfer varied with tea variety and increased with the decrease of TWR. The mean %PAH transfer with TWR = 1/150 was 1.12 and 1.65 times higher than that with TWR = 1/100 and 1/50, respectively. %PAH transfer reduced greatly as the brewing times increased. The mean %PAH transfer in the first brewing time occupied 51.6% of the total three mean %PAH transfers in the three brewing times. The mean %PAH transfer decreased by 30.4% after the tea had been washed immediately before brewing. Brewing the tea within uncovered cup diminished %PAH transfer by a degree of 4.31-31.7% compared to brewing the tea within a covered cup. PMID:16756366

  8. Cell surface-associated aggregation-promoting factor from Lactobacillus gasseri SBT2055 facilitates host colonization and competitive exclusion of Campylobacter jejuni.

    PubMed

    Nishiyama, Keita; Nakazato, Akiko; Ueno, Shintaro; Seto, Yasuyuki; Kakuda, Tsutomu; Takai, Shinji; Yamamoto, Yuji; Mukai, Takao

    2015-11-01

    Campylobacter jejuni, one of the most common causes of gastroenteritis worldwide, is transmitted to humans through poultry. We previously reported that Lactobacillus gasseri SBT2055 (LG2055) reduced C. jejuni infection in human epithelial cells in vitro and inhibited pathogen colonization of chickens in vivo. This suggested that the LG2055 adhesion and/or co-aggregation phenotype mediated by cell-surface aggregation-promoting factors (APFs) may be important for the competitive exclusion of C. jejuni. Here, we show that cell surface-associated APF1 promoted LG2055 self-aggregation and adhesion to human epithelial cells and exhibited high affinity for the extracellular matrix component fibronectin. These effects were absent in the apf1 knockout mutant, indicating the role of APF1 in LG2055-mediated inhibition of C. jejuni in epithelial cells and chicken colonization. Similar to APF1, APF2 promoted the co-aggregation of LG2055 and C. jejuni but did not inhibit C. jejuni infection. Our data suggest a pivotal role for APF1 in mediating the interaction of LG2055 with human intestinal cells and in inhibiting C. jejuni colonization of the gastrointestinal tract. We thus provide new insight into the health-promoting effects of probiotics and mechanisms of competitive exclusion in poultry. Further research is needed to determine whether the probiotic strains reach the epithelial surface. PMID:26239091

  9. Ultrastructural Study on Ultra-Low Frequency Electromagnetic Fields and Transfer Factor Effects on Skin Ulcers

    SciTech Connect

    Cadena, M. S. Reyes; Chapul, L. Sanchez; Perez, Javier; Garcia, M. N. Jimenez; Lopez, M. A. Jimenez; Espindola, M. E. Sanchez; Perez, R. Paniagua; Hernandez, N. A.; Paniagua, G.; Uribe, F.; Nava, J. J. Godina; Segura, M. A. Rodriguez

    2008-08-11

    We determined the effect of 120Hz ultra low frequency electromagnetic field (ELF) on the healing process of skin in 20 Wistar rats distributed in four groups in which chronic dermal ulcers had been produced. The first two groups received a dose of the transfer factor and interferon-beta (IFN-{beta}) every 24 h during 12 days. The third group (positive control) received only electromagnetic field (ELF) sessions, and in the fourth group (negative control), no treatment was applied. The electromagnetic field was applied through a Helmholtz coils; 30 Gauss of intensity. Results shown histological changes that improve the healing process in animals subjected to ELF together with the transfer factor.

  10. Energy transfer between a nanosystem and its host fluid: A multiscale factorization approach

    SciTech Connect

    Sereda, Yuriy V.; Espinosa-Duran, John M.; Ortoleva, Peter J.

    2014-02-21

    Energy transfer between a macromolecule or supramolecular assembly and a host medium is considered from the perspective of Newton's equations and Lie-Trotter factorization. The development starts by demonstrating that the energy of the molecule evolves slowly relative to the time scale of atomic collisions-vibrations. The energy is envisioned to be a coarse-grained variable that coevolves with the rapidly fluctuating atomistic degrees of freedom. Lie-Trotter factorization is shown to be a natural framework for expressing this coevolution. A mathematical formalism and workflow for efficient multiscale simulation of energy transfer is presented. Lactoferrin and human papilloma virus capsid-like structure are used for validation.

  11. Ultrastructural Study on Ultra-Low Frequency Electromagnetic Fields and Transfer Factor Effects on Skin Ulcers

    NASA Astrophysics Data System (ADS)

    Cadena, M. S. Reyes; Chapul, L. Sánchez; Pérez, Javiér; García, M. N. Jiménez; López, M. A. Jiménez; Espíndola, M. E. Sánchez; Perez, R. Paniagua; Hernández, N. A.; Paniagua, G.; Uribe, F.; Nava, J. J. Godina; Segura, M. A. Rodríguez

    2008-08-01

    We determined the effect of 120Hz ultra low frequency electromagnetic field (ELF) on the healing process of skin in 20 Wistar rats distributed in four groups in which chronic dermal ulcers had been produced. The first two groups received a dose of the transfer factor and interferon-beta (IFN-β) every 24 h during 12 days. The third group (positive control) received only electromagnetic field (ELF) sessions, and in the fourth group (negative control), no treatment was applied. The electromagnetic field was applied through a Helmholtz coils; 30 Gauss of intensity. Results shown histological changes that improve the healing process in animals subjected to ELF together with the transfer factor.

  12. Energy transfer between a nanosystem and its host fluid: A multiscale factorization approach

    NASA Astrophysics Data System (ADS)

    Sereda, Yuriy V.; Espinosa-Duran, John M.; Ortoleva, Peter J.

    2014-02-01

    Energy transfer between a macromolecule or supramolecular assembly and a host medium is considered from the perspective of Newton's equations and Lie-Trotter factorization. The development starts by demonstrating that the energy of the molecule evolves slowly relative to the time scale of atomic collisions-vibrations. The energy is envisioned to be a coarse-grained variable that coevolves with the rapidly fluctuating atomistic degrees of freedom. Lie-Trotter factorization is shown to be a natural framework for expressing this coevolution. A mathematical formalism and workflow for efficient multiscale simulation of energy transfer is presented. Lactoferrin and human papilloma virus capsid-like structure are used for validation.

  13. Weighted aggregation

    NASA Technical Reports Server (NTRS)

    Feiveson, A. H. (Principal Investigator)

    1979-01-01

    The use of a weighted aggregation technique to improve the precision of the overall LACIE estimate is considered. The manner in which a weighted aggregation technique is implemented given a set of weights is described. The problem of variance estimation is discussed and the question of how to obtain the weights in an operational environment is addressed.

  14. Factors affecting the efficiency of foal production in a commercial oocyte transfer program.

    PubMed

    Riera, Fernando L; Roldán, Jaime E; Gomez, José; Hinrichs, Katrin

    2016-04-01

    Transfer of donor oocytes to the oviducts of inseminated recipient mares (oocyte transfer, OT) presents a valuable method for production of foals from otherwise infertile mares. Little information is available, however, on factors affecting success of OT in a clinical setting. We report the findings over three breeding seasons in a commercial OT program developed at an equine embryo transfer center in Argentina. Overall, 25 mares were enrolled, and 197 follicle aspiration procedures were performed. The average mare age was 23 years. Follicle aspiration was performed with a needle placed through the flank; the oocyte recovery rate per follicle aspirated was 149 of 227 (66%). Induction of donor ovulation with deslorelin + hCG resulted in a significantly higher oocyte recovery rate than did induction with deslorelin alone (75% vs. 58%). There was no significant effect of mare age (17-20, 21-24, or 25-27 years) on oocyte recovery rate. Twelve oocytes were degenerating or lost during handling; transfer of the remaining 137 oocytes resulted in 42 pregnancies (31%) at 14 days. Of these, 32 (23% per transfer) went on to produce a foal or ongoing pregnancy. Transfer of oocytes recovered with a compact cumulus, without donor follicle induction, or less than 20 hours after induction was associated with a significantly reduced pregnancy rate (1/16, 6%), as was use of noncycling, hormone-treated recipients (2/22, 9%). To evaluate management factors affecting pregnancy rate, noncycling, hormone-treated recipients were disregarded, and only procedures using mature (expanded cumulus) oocytes recovered and transferred on the standard schedule (n = 99) were included. Mare age did not significantly affect rates of pregnancy or pregnancy loss. Similar pregnancy rates were obtained using recipients inseminated from 1 to 27 hours before transfer. Counterintuitively, insemination of recipients immediately (1-2 hours) after aspiration of the recipient follicle was associated with

  15. The Role of Individual and Training Design Factors on Training Transfer

    ERIC Educational Resources Information Center

    Bhatti, Muhammad Awais; Kaur, Sharan

    2010-01-01

    Purpose: The purpose of this study is to highlight the role of individual and training design factors on training transfer. Design/methodology/approach: A review of the literature is conducted, and this review highlights a dual role of perceived content validity in the form of increasing self-efficacy and the role of trainees' reaction. The study…

  16. Monte Carlo direct view factor and generalized radiative heat transfer programs

    NASA Technical Reports Server (NTRS)

    Mc Williams, J. L.; Scates, J. H.

    1969-01-01

    Computer programs find the direct view factor from one surface segment to another using the Monte carlo technique, and the radioactive-transfer coefficients between surface segments. An advantage of the programs is the great generality of problems treatable and rapidity of solution from problem conception to receipt of results.

  17. PSYCHOLOGICAL AND EDUCATIONAL FACTORS IN TRANSFER OF TRAINING, PHASE I. QUARTERLY REPORTS 2 AND 3.

    ERIC Educational Resources Information Center

    STOLUROW, LAWRENCE M.

    PSYCHOLOGICAL AND EDUCATIONAL FACTORS INVOLVED IN THE TRANSFER OF TRAINING WERE STUDIED BY USE OF PROGRAMED SELF-INSTRUCTION USING TEACHING MACHINES. THIS MEDIUM WAS CHOSEN BECAUSE IT PROVIDES LABORATORY-LIKE CONDITIONS SUCH AS STABILIZED METHODS, AND STIMULUS CONTROL INCLUDING CONTROL OF TEACHER PERSONALITY, PLUS A STEP-BY-STEP RECORD OF THE…

  18. Factors Associated with Transfer of Training in Workplace E-Learning

    ERIC Educational Resources Information Center

    Park, Ji-Hye; Wentling, Tim

    2007-01-01

    Purpose--The purpose of this study is to investigate the effect of factors associated with e-learning, particularly computer attitudes and usability, on transfer of training in workplace e-learning courses. Design/methodology/approach--This study relied on quantitative data obtained from four online survey questionnaires. The sample of this study…

  19. DEVELOPMENT OF AN AIR-TO-LEAF VAPOR PHASE TRANSFER FACTOR FOR DIOXINS AND FURANS

    EPA Science Inventory

    Results of an experiment in which grass was grown in a greenhouse and outdoors, and in soils of different concentration levels of dioxins and furans, were used in a modeling exercise to derive an air-to-leaf vapor phase transfer factor. The purpose of the experiment was to under...

  20. A Transfer Learning Approach for Applying Matrix Factorization to Small ITS Datasets

    ERIC Educational Resources Information Center

    Voß, Lydia; Schatten, Carlotta; Mazziotti, Claudia; Schmidt-Thieme, Lars

    2015-01-01

    Machine Learning methods for Performance Prediction in Intelligent Tutoring Systems (ITS) have proven their efficacy; specific methods, e.g. Matrix Factorization (MF), however suffer from the lack of available information about new tasks or new students. In this paper we show how this problem could be solved by applying Transfer Learning (TL),…

  1. Factors Influencing Pronunciation Accuracy: L1 Negative Transfer, Task Variables and Individual Aptitude

    ERIC Educational Resources Information Center

    Liu, Qian

    2011-01-01

    This paper investigates the influence of three factors on pronunciation accuracy of Chinese adult foreign language learners. Ten target sounds including phonemes and syllables are included in the pre-test, an analysis of which shows that the mispronunciation of the randomly chosen target sounds mainly results from L1 negative transfer. It is…

  2. Factors Contributing to the Upward Transfer of Baccalaureate Aspirants Beginning at Community Colleges

    ERIC Educational Resources Information Center

    Wang, Xueli

    2012-01-01

    This study examined factors associated with the upward transfer of baccalaureate aspirants beginning at community colleges. Based on data from the National Education Longitudinal Study of 1988 and the Postsecondary Education Transcript Study, a sequential logistic regression analysis was conducted to predict bachelor's degree-seeking community…

  3. Occurrence of platelet-activating factor (PAF) and an endogenous inhibitor of platelet aggregation in diffuse cutaneous mastocytosis.

    PubMed Central

    Macpherson, J L; Kemp, A; Rogers, M; Mallet, A I; Toia, R F; Spur, B; Earl, J W; Chesterman, C N; Krilis, S A

    1989-01-01

    We have identified PAF in the blister fluid from a patient with bullous mastocytosis, a rare form of mast-cell disease. We have found a novel endogenous inhibitor of platelet aggregation which obscured the presence of the PAF in unprocessed blister fluid and in ethanol or lipid extracts. The PAF was characterized by the demonstration of chromatographic, mass spectral and biological properties identical to those of authentic PAF. Thus this is the first demonstration of PAF in biological fluid from a patient with mastocytosis. High levels of immunoreactive prostaglandin D2 (PGD2) and histamine were also present in the blister fluid. The interaction between PAF and the inhibitor of platelet aggregation in patients with systemic mastocytosis may provide an explanation for some of the manifestations of the disease, in particular the episodic hypotension, cutaneous flushing and pallor. PMID:2805409

  4. A Novel Direct Factor Xa Inhibitory Peptide with Anti-Platelet Aggregation Activity from Agkistrodon acutus Venom Hydrolysates

    PubMed Central

    Chen, Meimei; Ye, Xiaohui; Ming, Xin; Chen, Yahui; Wang, Ying; Su, Xingli; Su, Wen; Kong, Yi

    2015-01-01

    Snake venom is a natural substance that contains numerous bioactive proteins and peptides, nearly all of which have been identified over the last several decades. In this study, we subjected snake venom to enzymatic hydrolysis to identify previously unreported bioactive peptides. The novel peptide ACH-11 with the sequence LTFPRIVFVLG was identified with both FXa inhibition and anti-platelet aggregation activities. ACH-11 inhibited the catalytic function of FXa towards its substrate S-2222 via a mixed model with a Ki value of 9.02 μM and inhibited platelet aggregation induced by ADP and U46619 in a dose-dependent manner. Furthermore, ACH-11 exhibited potent antithrombotic activity in vivo. It reduced paralysis and death in an acute pulmonary thrombosis model by 90% and attenuated thrombosis weight in an arterio-venous shunt thrombosis model by 57.91%, both at a dose of 3 mg/kg. Additionally, a tail cutting bleeding time assay revealed that ACH-11 did not prolong bleeding time in mice at a dose of 3 mg/kg. Together, our results reveal that ACH-11 is a novel antithrombotic peptide exhibiting both FXa inhibition and anti-platelet aggregation activities, with a low bleeding risk. We believe that it could be a candidate or lead compound for new antithrombotic drug development. PMID:26035670

  5. Controlled Dual Growth Factor Delivery From Microparticles Incorporated Within Human Bone Marrow-Derived Mesenchymal Stem Cell Aggregates for Enhanced Bone Tissue Engineering via Endochondral Ossification

    PubMed Central

    Dang, Phuong N.; Dwivedi, Neha; Phillips, Lauren M.; Yu, Xiaohua; Herberg, Samuel; Bowerman, Caitlin; Solorio, Loran D.; Murphy, William L.

    2016-01-01

    Bone tissue engineering via endochondral ossification has been explored by chondrogenically priming cells using soluble mediators for at least 3 weeks to produce a hypertrophic cartilage template. Although recapitulation of endochondral ossification has been achieved, long-term in vitro culture is required for priming cells through repeated supplementation of inductive factors in the media. To address this challenge, a microparticle-based growth factor delivery system was engineered to drive endochondral ossification within human bone marrow-derived mesenchymal stem cell (hMSC) aggregates. Sequential exogenous presentation of soluble transforming growth factor-β1 (TGF-β1) and bone morphogenetic protein-2 (BMP-2) at various defined time courses resulted in varying degrees of chondrogenesis and osteogenesis as demonstrated by glycosaminoglycan and calcium content. The time course that best induced endochondral ossification was used to guide the development of the microparticle-based controlled delivery system for TGF-β1 and BMP-2. Gelatin microparticles capable of relatively rapid release of TGF-β1 and mineral-coated hydroxyapatite microparticles permitting more sustained release of BMP-2 were then incorporated within hMSC aggregates and cultured for 5 weeks following the predetermined time course for sequential presentation of bioactive signals. Compared with cell-only aggregates treated with exogenous growth factors, aggregates with incorporated TGF-β1- and BMP-2-loaded microparticles exhibited enhanced chondrogenesis and alkaline phosphatase activity at week 2 and a greater degree of mineralization by week 5. Staining for types I and II collagen, osteopontin, and osteocalcin revealed the presence of cartilage and bone. This microparticle-incorporated system has potential as a readily implantable therapy for healing bone defects without the need for long-term in vitro chondrogenic priming. Significance This study demonstrates the regulation of chondrogenesis

  6. Controlled Dual Growth Factor Delivery From Microparticles Incorporated Within Human Bone Marrow-Derived Mesenchymal Stem Cell Aggregates for Enhanced Bone Tissue Engineering via Endochondral Ossification.

    PubMed

    Dang, Phuong N; Dwivedi, Neha; Phillips, Lauren M; Yu, Xiaohua; Herberg, Samuel; Bowerman, Caitlin; Solorio, Loran D; Murphy, William L; Alsberg, Eben

    2016-02-01

    Bone tissue engineering via endochondral ossification has been explored by chondrogenically priming cells using soluble mediators for at least 3 weeks to produce a hypertrophic cartilage template. Although recapitulation of endochondral ossification has been achieved, long-term in vitro culture is required for priming cells through repeated supplementation of inductive factors in the media. To address this challenge, a microparticle-based growth factor delivery system was engineered to drive endochondral ossification within human bone marrow-derived mesenchymal stem cell (hMSC) aggregates. Sequential exogenous presentation of soluble transforming growth factor-β1 (TGF-β1) and bone morphogenetic protein-2 (BMP-2) at various defined time courses resulted in varying degrees of chondrogenesis and osteogenesis as demonstrated by glycosaminoglycan and calcium content. The time course that best induced endochondral ossification was used to guide the development of the microparticle-based controlled delivery system for TGF-β1 and BMP-2. Gelatin microparticles capable of relatively rapid release of TGF-β1 and mineral-coated hydroxyapatite microparticles permitting more sustained release of BMP-2 were then incorporated within hMSC aggregates and cultured for 5 weeks following the predetermined time course for sequential presentation of bioactive signals. Compared with cell-only aggregates treated with exogenous growth factors, aggregates with incorporated TGF-β1- and BMP-2-loaded microparticles exhibited enhanced chondrogenesis and alkaline phosphatase activity at week 2 and a greater degree of mineralization by week 5. Staining for types I and II collagen, osteopontin, and osteocalcin revealed the presence of cartilage and bone. This microparticle-incorporated system has potential as a readily implantable therapy for healing bone defects without the need for long-term in vitro chondrogenic priming. Significance: This study demonstrates the regulation of chondrogenesis

  7. Transfer of Drug Resistance Factors to the Dimorphic Bacterium CAULOBACTER CRESCENTUS

    PubMed Central

    Ely, Bert

    1979-01-01

    The P-type drug resistance factors RP4, RK2, R702, R68.45, and the N-type drug resistance factor R46 are transferred to Caulobacter crescentus at high frequencies. They are stably maintained and their antibiotic resistances are expressed. Experiments with RP4 have shown that intergeneric transfer of RP4 occurs with greater than 90% of the recipient cells in filter matings between Escherichia coli donors and C. crescentus recipients. Reciprocal matings with C. crescentus donors are less efficient, but still occur at a frequency of 10-1. C. crescentus strains maintain RP4 as a plasmid, are sensitive to RP4-specific phage, and segregate phage-resistant cells at a frequency of 10-4 to 10-5. The RP4 plasmid can be used in several ways: (1) the RP4 plasmid will promote chromosomal exchange between C. crescentus strains at frequencies ranging from 10-6 to 10-8; (2) RP4 will promote the transfer of nonconjugative colE1 plasmids from E. coli to C. crescentus; once transferred, the colE1 plasmid is stably maintained under nonselective conditions, can be transferred serially, and segregates independently from RP4; and (3) RP4 can be used to introduce transposons into the C. crescentus chromosome, providing the basis for additional genetic techniques. PMID:378764

  8. Construction aggregates

    USGS Publications Warehouse

    Langer, W.H.; Tepordei, V.V.; Bolen, W.P.

    2000-01-01

    Construction aggregates consist primarily of crushed stone and construction sand and gravel. Total estimated production of construction aggregates increased in 1999 by about 2% to 2.39 Gt (2.64 billion st) compared with 1998. This record production level continued an expansion that began in 1992. By commodities, crushed stone production increased 3.3%, while sand and gravel production increased by about 0.5%.

  9. Construction aggregates

    USGS Publications Warehouse

    Tepordei, V.V.

    1994-01-01

    Part of a special section on industrial minerals in 1993. The 1993 production of construction aggregates increased 6.3 percent over the 1992 figure, to reach 2.01 Gt. This represents the highest estimated annual production of combined crushed stone and construction sand and gravel ever recorded in the U.S. The outlook for construction aggregates and the issues facing the industry are discussed.

  10. Proteins aggregation and human diseases

    NASA Astrophysics Data System (ADS)

    Hu, Chin-Kun

    2015-04-01

    Many human diseases and the death of most supercentenarians are related to protein aggregation. Neurodegenerative diseases include Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), frontotemporallobar degeneration, etc. Such diseases are due to progressive loss of structure or function of neurons caused by protein aggregation. For example, AD is considered to be related to aggregation of Aβ40 (peptide with 40 amino acids) and Aβ42 (peptide with 42 amino acids) and HD is considered to be related to aggregation of polyQ (polyglutamine) peptides. In this paper, we briefly review our recent discovery of key factors for protein aggregation. We used a lattice model to study the aggregation rates of proteins and found that the probability for a protein sequence to appear in the conformation of the aggregated state can be used to determine the temperature at which proteins can aggregate most quickly. We used molecular dynamics and simple models of polymer chains to study relaxation and aggregation of proteins under various conditions and found that when the bending-angle dependent and torsion-angle dependent interactions are zero or very small, then protein chains tend to aggregate at lower temperatures. All atom models were used to identify a key peptide chain for the aggregation of insulin chains and to find that two polyQ chains prefer anti-parallel conformation. It is pointed out that in many cases, protein aggregation does not result from protein mis-folding. A potential drug from Chinese medicine was found for Alzheimer's disease.

  11. Highly Efficient Far Red/Near-Infrared Solid Fluorophores: Aggregation-Induced Emission, Intramolecular Charge Transfer, Twisted Molecular Conformation, and Bioimaging Applications.

    PubMed

    Lu, Hongguang; Zheng, Yadan; Zhao, Xiaowei; Wang, Lijuan; Ma, Suqian; Han, Xiongqi; Xu, Bin; Tian, Wenjing; Gao, Hui

    2016-01-01

    The development of organic fluorophores with efficient solid-state emissions or aggregated-state emissions in the red to near-infrared region is still challenging. Reported herein are fluorophores having aggregation-induced emission ranging from the orange to far red/near-infrared (FR/NIR) region. The bioimaging performance of the designed fluorophore is shown to have potential as FR/NIR fluorescent probes for biological applications. PMID:26576818

  12. 134Cs transfer factors to green gram and soybean as influenced by waste mica.

    PubMed

    Sreenivasa Chari, M; Manjaiah, K M; Sachdev, P; Sachdev, M S

    2012-02-01

    Greenhouse pot culture experiment was carried out to study the (134)Cs transfer factors from soils to green gram and soybean as influenced by waste mica application (@ 0, 10, 20, 40 g mica kg(-1) soil) and compared with muriate of potash (MOP) application (0.17 g kg(-1) soil). For the study, the soils were contaminated with (134)Cs radionuclide @ 37 kBq kg(-1) soil. The shoot biomass and K uptake by crops were significantly improved with waste mica application (@ 40 g kg(-1) soil). Compared to control, waste mica and MOP application significantly improved the yield, K content in plant and its uptake. Amongst the soils, crops grown in vertisol recorded higher shoot biomass compared to inceptisol and ultisol. Irrespective of the treatments, higher (134)Cs transfer factors were seen in ultisol (0.30) as compared to inceptisol (0.16) and vertisol (0.13). It was observed that higher the K concentration in soil and plant, lowered (134)Cs transfer to green gram and soybean. The study recommended that waste mica @ 20 g kg(-1) would be useful for checking the (134)Cs transfer factors from soils to green gram and soybean. PMID:22115435

  13. The ultrasonic-enhanced factor of mass-transfer coefficient in the supercritical carbon dioxide extraction

    NASA Astrophysics Data System (ADS)

    Luo, Benyi; Lu, Yigang

    2008-10-01

    Based on several hypotheses about the process of supercritical carbon dioxide extraction, the onflow around the solute granule is figured out by the Navier-Stocks equation. In combination with the Higbie’s solute infiltration model, the link between the mass-transfer coefficient and the velocity of flow is found. The mass-transfer coefficient with the ultrasonical effect is compared with that without the ultrasonical effect, and then a new parameter named the ultrasonic-enhanced factor of mass-transfer coefficient is brought forward, which describes the mathematical model of the supercritical carbon dioxide extraction process enhanced by ultrasonic. The model gives out the relationships among the ultrasonical power, the ultrasonical frequency, the radius of solute granule and the ultrasonic-enhanced factor of mass-transfer coefficient. The results calculated by this model fit well with the experimental data, including the extraction of Coix Lacryma-jobi Seed Oil (CLSO) and Coix Lacryma-jobi Seed Ester (CLSE) from coix seeds and the extraction of Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) from the alga by means of the ultrasonic-enhanced supercritical carbon dioxide extraction (USFE) and the supercritical carbon dioxide extraction (SFE) respectively. This proves the rationality of the ultrasonic-enhanced factor model. The model provides a theoretical basis for the application of ultrasonic-enhanced supercritical fluid extraction technique.

  14. Recoil polarization measurements of the proton electromagnetic form factor ratio at high momentum transfer

    SciTech Connect

    Andrew Puckett

    2009-12-01

    Electromagnetic form factors are fundamental properties of the nucleon that describe the effect of its internal quark structure on the cross section and spin observables in elastic lepton-nucleon scattering. Double-polarization experiments have become the preferred technique to measure the proton and neutron electric form factors at high momentum transfers. The recently completed GEp-III experiment at the Thomas Jefferson National Accelerator Facility used the recoil polarization method to extend the knowledge of the proton electromagnetic form factor ratio GpE/GpM to Q2 = 8.5 GeV2. In this paper we present the preliminary results of the experiment.

  15. Scale-model charge-transfer technique for measuring enhancement factors

    NASA Technical Reports Server (NTRS)

    Kositsky, J.; Nanevicz, J. E.

    1991-01-01

    Determination of aircraft electric field enhancement factors is crucial when using airborne field mill (ABFM) systems to accurately measure electric fields aloft. SRI used the scale model charge transfer technique to determine enhancement factors of several canonical shapes and a scale model Learjet 36A. The measured values for the canonical shapes agreed with known analytic solutions within about 6 percent. The laboratory determined enhancement factors for the aircraft were compared with those derived from in-flight data gathered by a Learjet 36A outfitted with eight field mills. The values agreed to within experimental error (approx. 15 percent).

  16. Survey of literature on convective heat transfer coefficients and recovery factors for high atmosphere thermometry

    NASA Technical Reports Server (NTRS)

    Chung, S.

    1973-01-01

    Heat transfer phenomena of rarefied gas flows is discussed based on a literature survey of analytical and experimental rarefied gas dynamics. Subsonic flows are emphasized for the purposes of meteorological thermometry in the high atmosphere. The heat transfer coefficients for three basic geometries are given in the regimes of free molecular flow, transition flow, slip flow, and continuum flow. Different types of heat phenomena, and the analysis of theoretical and experimental data are presented. The uncertainties calculated from the interpolation rule compared with the available experimental data are discussed. The recovery factor for each geometry in subsonic rarefied flows is also given.

  17. Experimental methodologies and preliminary transfer factor data for estimation of dermal exposures to particles.

    PubMed

    Rodes, C E; Newsome, J R; Vanderpool, R W; Antley, J T; Lewis, R G

    2001-01-01

    Developmental efforts and experimental data that focused on quantifying the transfer of particles on a mass basis from indoor surfaces to human skin are described. Methods that utilized a common fluorescein-tagged Arizona Test Dust (ATD) as a possible surrogate for housedust and a uniform surface dust deposition chamber to permit estimation of particle mass transfer for selected dust size fractions were developed. Particle transfers to both wet and dry skin were quantified for contact events with stainless steel, vinyl, and carpeted surfaces that had been pre-loaded with the tagged test dust. To better understand the representativeness of the test dust, a large housedust sample was collected and analyzed for particle size distribution by mass and several metals (Pb, Mn, Cd, Cr, and Ni). The real housedust sample was found to have multimodal size distributions (mg/g) for particle-phase metals. The fluorescein tagging provided surface coatings of 0.11-0.36 ng fluorescein per gram of dust. The predominant surface location of the fluorescein tag would best represent simulated mass transfers for contaminant species coating the surfaces of the particles. The computer-controlled surface deposition chamber provided acceptably uniform surface coatings with known particle loadings on the contact test panels. Significant findings for the dermal transfer factor data were: (a) only about 1/3 of the projected hand surface typically came in contact with the smooth test surfaces during a press; (b) the fraction of particles transferred to the skin decreased as the surface roughness increased, with carpeting transfer coefficients averaging only 1/10 those of stainless steel; (c) hand dampness significantly increased the particle mass transfer; (d) consecutive presses decreased the particle transfer by a factor of 3 as the skin surface became loaded, requiring approximately 100 presses to reach an equilibrium transfer rate; and (e) an increase in metals concentration with decreasing

  18. Platelet factor XIIIa release during platelet aggregation and plasma clot strength measured by thrombelastography in patients with coronary artery disease treated with clopidogrel.

    PubMed

    Kreutz, Rolf P; Owens, Janelle; Lu, Deshun; Nystrom, Perry; Jin, Yan; Kreutz, Yvonne; Desta, Zeruesenay; Flockhart, David A

    2015-01-01

    It has been estimated that up to half of circulating factor XIIIa (FXIIIa) is stored in platelets. The release of FXIIIa from platelets upon stimulation with adenosine diphosphate (ADP) in patients with coronary artery disease treated with dual antiplatelet therapy has not been previously examined. Samples from 96 patients with established coronary artery disease treated with aspirin and clopidogrel were examined. Platelet aggregation was performed by light transmittance aggregometry in platelet-rich plasma (PRP), with platelet-poor plasma (PPP) as reference, and ADP 5 µM as agonist. Kaolin-activated thrombelastography (TEG) was performed in citrate PPP. PRP after aggregation was centrifuged and plasma supernatant (PSN) collected. FXIIIa was measured in PPP and PSN. Platelet aggregation after stimulation with ADP 5 µM resulted in 24% additional FXIIIa release in PSN as compared to PPP (99.3 ± 27 vs. 80.3 ± 24%, p < 0.0001). FXIIIa concentration in PSN correlated with maximal plasma clot strength (TEG-G) (r = 0.48, p < 0.0001), but not in PPP (r = 0.15, p = 0.14). Increasing quartiles of platelet-derived FXIIIa were associated with incrementally higher TEG-G (p = 0.012). FXIIIa release was similar between clopidogrel responders and non-responders (p = 0.18). In summary, platelets treated with aspirin and clopidogrel release a significant amount of FXIIIa upon aggregation by ADP. Platelet-derived FXIIIa may contribute to differences in plasma TEG-G, and thus, in part, provide a mechanistic explanation for high clot strength observed as a consequence of platelet activation. Variability in clopidogrel response does not significantly influence FXIIIa release from platelets. PMID:24833046

  19. Platelet Factor XIIIa Release During Platelet Aggregation and Plasma Clot Strength Measured by Thrombelastography in Patients with Coronary Artery Disease Treated with Clopidogrel

    PubMed Central

    Kreutz, Rolf P.; Owens, Janelle; Lu, Deshun; Nystrom, Perry; Jin, Yan; Kreutz, Yvonne; Desta, Zeruesenay; Flockhart, David A.

    2016-01-01

    It has been estimated that up to half of circulating Factor XIIIa (FXIIIa) is stored in platelets. The release of FXIIIa from platelets upon stimulation with ADP in patients with coronary artery disease treated with dual antiplatelet therapy has not been previously examined. Samples from 96 patients with established coronary artery disease treated with aspirin and clopidogrel were examined. Platelet aggregation was performed by light transmittance aggregometry (LTA) in platelet rich plasma (PRP) with platelet poor plasma (PPP) as reference and ADP 5μM as agonist. Kaolin activated TEG was performed in citrate PPP. PRP after aggregation was centrifuged and plasma supernatant (PSN) collected. FXIIIa was measured in PPP and PSN. Platelet aggregation after stimulation with ADP 5μM resulted in 24% additional FXIIIa release in PSN as compared to PPP (99.3 ± 27 vs. 80.3 ± 24 %, p<0.0001). FXIIIa concentration in PSN correlated with maximal plasma clot strength (TEG-G) (r=0.48, p<0.0001), but not in PPP (r=0.15, p=0.14). Increasing quartiles of platelet derived FXIIIa were associated with incrementally higher TEG-G (p=0.012). FXIIIa release was similar between clopidogrel responders and non-responders (p=0.18). In summary, platelets treated with aspirin and clopidogrel release a significant amount of FXIIIa upon aggregation by ADP. Platelet derived FXIIIa may contribute to differences in plasma TEG-G, and thus in part provide a mechanistic explanation for high clot strength observed as a consequence of platelet activation. Variability in clopidogrel response does not significantly influence FXIIIa release from platelets. PMID:24833046

  20. Strand Transfer and Elongation of HIV-1 Reverse Transcription Is Facilitated by Cell Factors In Vitro

    PubMed Central

    Warrilow, David; Warren, Kylie; Harrich, David

    2010-01-01

    Recent work suggests a role for multiple host factors in facilitating HIV-1 reverse transcription. Previously, we identified a cellular activity which increases the efficiency of HIV-1 reverse transcription in vitro. Here, we describe aspects of the activity which shed light on its function. The cellular factor did not affect synthesis of strong-stop DNA but did improve downstream DNA synthesis. The stimulatory activity was isolated by gel filtration in a single fraction of the exclusion volume. Velocity-gradient purified HIV-1, which was free of detectable RNase activity, showed poor reverse transcription efficiency but was strongly stimulated by partially purified cell proteins. Hence, the cell factor(s) did not inactivate an RNase activity that might degrade the viral genomic RNA and block completion of reverse transcription. Instead, the cell factor(s) enhanced first strand transfer and synthesis of late reverse transcription suggesting it stabilized the reverse transcription complex. The factor did not affect lysis of HIV-1 by Triton X-100 in the endogenous reverse transcription (ERT) system, and ERT reactions with HIV-1 containing capsid mutations, which varied the biochemical stability of viral core structures and impeded reverse transcription in cells, showed no difference in the ability to be stimulated by the cell factor(s) suggesting a lack of involvement of the capsid in the in vitro assay. In addition, reverse transcription products were found to be resistant to exogenous DNase I activity when the active fraction was present in the ERT assay. These results indicate that the cell factor(s) may improve reverse transcription by facilitating DNA strand transfer and DNA synthesis. It also had a protective function for the reverse transcription products, but it is unclear if this is related to improved DNA synthesis. PMID:20949087

  1. [Team-based community psychiatry: importance of context factors and transferability of evidence from studies].

    PubMed

    Weinmann, S; Gühne, U; Kösters, M; Gaebel, W; Becker, T

    2012-07-01

    The German Society for Psychiatry, Psychotherapy and Neurology (DGPPN) guidelines on psychosocial interventions for people with severe mental illness appraise the transferability of results of trials evaluating community-based mental health services to the German situation. This assessment has to draw on research results on factors determining effectiveness. This must be seen against the background of a lack of high-quality trials in Germany. The article discusses system, context and setting factors related to the transfer of evidence on community-based service models from other countries. These issues are discussed on the basis of evidence concerning the models of case management, assertive community treatment and community mental health teams. International differences in study findings are highlighted and the importance of treatment-as-usual in influencing study results is emphasized. The more control services including elements of community-based care there are and the less the pressure to reduce inpatient treatment (threshold to inpatient care admission), the smaller the relative effect sizes of innovative care models will be.In the absence of direct evidence, careful examination of transferability is required before introducing health care models. Research has revealed solid evidence for several factors influencing the effects of innovative community mental health care. Among key factors in the care of people with severe mental illness, home visits and joint team responsibility for both psychiatric and social care were identified. This evidence can facilitate the adaptation of successful mental health care models in Germany. PMID:22688090

  2. Measured elemental transfer factors for boreal hunter/gatherer scenarios: fish, game and berries.

    PubMed

    Sheppard, S C; Long, J M; Sanipelli, B

    2010-11-01

    The environmental assessment of long-term nuclear waste management requires data to estimate food chain transfers for radionuclides in various environmental settings. For key elements such as iodine (I) and chlorine (Cl), there is a paucity of transfer factor data, particularly outside of agricultural food chains. This study dealt with transfers of I, Cl and 28 other elements to foods that would be typical of boreal hunter/gatherer lifestyles, as well as being common foods for modern recreational and subsistence hunters. Food/substrate concentration ratios (CRs) and related transfer factors for eight species of widely distributed fish, whitetail deer (Odocoileus virginianus), Canada geese (Branta canadensis) and wild blueberries (Vaccinium myrtilloides) were measured and compared to the literature. Limited data were obtained for caribou (Rangifer tarandus), elk (Cervus elaphus) and moose (Alces americanus). Freshwater sediment Kd values and CRs for a ubiquitous freshwater macrophyte were also obtained. The CRs for I in fish were 29Lkg(-1) in edible muscle (fillets) of large-bodied species and 85Lkg(-1) for whole, small-bodied fish. The logCRs for fish and macrophytes were correlated across elements. For several elements, the Kds for sediments in deep water were approximately 4-fold higher than for littoral samples. The elemental transfers to wild animals for some elements were notably different than the literature indicates for domestic animals. It is argued that the transfer data obtained using indigenous elements from real environmental settings, as opposed to contaminant elements in experimental or impacted environments, are especially relevant to assessment of long-term impacts. PMID:20619514

  3. Transfer Students in STEM Majors: Gender Differences in the Socialization Factors that Influence Academic and Social Adjustment

    ERIC Educational Resources Information Center

    Jackson, Dimitra Lynette

    2010-01-01

    The purposes of this study were (a) to examine the socialization factors of community college transfer students in Science, Technology, Engineering and Mathematics (STEM); (b) to examine the socialization factors that impact the academic and social adjustment of community college transfer students in STEM majors; and (c) to understand how female…

  4. Effect of Plant and Environmental Factors on ALS-resistant Gene Transfer from ClearfieldTM Rice to Red Rice.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Imazethapyr-resistant gene from ClearfieldTM (CL) rice varieties transfers through pollen flow to red rice (Oryza sativa L.), a noxious weed in rice production in southern states. Factors which affect gene transfer rate include, but are not limited to, plant and environmental factors. Thus, we aimed...

  5. Social Factors that Impact Women's Practice of Breast Self-Examination: A Challenge to the Transfer of Training Literature

    ERIC Educational Resources Information Center

    London, Patricia A.; Flannery, Daniele D.

    2004-01-01

    The purpose of the qualitative study was to understand how social factors might help or hinder the training transfer process. Specifically, this qualitative research looked at the meanings a group of women attached to social factors that might influence their practice of breast self-exam. Implications for transfer of training are suggested.…

  6. PSYCHOLOGICAL AND EDUCATIONAL FACTORS IN TRANSFER OF TRAINING, SECTION TWO--BIBLIOGRAPHY OF STUDIES OF TRANSFER OF TRAINING.

    ERIC Educational Resources Information Center

    STOLUROW, LAWRENCE M.; AND OTHERS

    THIS BIBLIOGRAPHY ON TRANSFER OF LEARNING STUDIES WAS COMPLETED FOR U.S. OFFICE OF EDUCATION CONTRACT NO. 4-20-002 AS APPENDIX "A" (SECTION TWO) TO THE FINAL REPORT. IT CONTAINS 1,775 TITLES FROM THE PERIOD 1890 TO 1966 ON TRANSFER OF LEARNING. THE CONCERN WAS TO COMPILE THE EMPIRICALLY BASED PRINCIPLES RELATING TO TRANSFER OF TRAINING IN A FORM…

  7. Enhanced expression of Aggrus (T1alpha/podoplanin), a platelet-aggregation-inducing factor in lung squamous cell carcinoma.

    PubMed

    Kato, Yukinari; Kaneko, Mika; Sata, Makoto; Fujita, Naoya; Tsuruo, Takashi; Osawa, Motoki

    2005-01-01

    Aggrus (T1alpha/podoplanin, known as a specific marker for type I alveolar cells or lymphatic endothelial cells) is a transmembrane sialoglycoprotein that aggregates platelets. Previously, we showed that upregulated expression of Aggrus occurs in colorectal tumors or testicular tumors and could be associated with platelet-aggregating activity and metastatic ability. In testicular tumors, Aggrus is specifically expressed in seminoma. The present study investigates Aggrus expression in human primary lung cancer tissues of different types. Microarray analysis demonstrated that aggrus was significantly expressed in squamous cell carcinoma (10/15; 66.7%). Immunohistochemical analysis also showed that the incidence of positive staining in sections of squamous cell carcinoma (7/8; 87.5%) was higher than that in adenocarcinoma (2/13; 15.4%). Furthermore, Aggrus expression was detected in a squamous cell carcinoma cell line, NCI-H226, by real-time PCR. These findings indicated that overexpression of Aggrus occurred in squamous cell carcinoma of the lung. Therefore, Aggrus could be a useful diagnostic marker for squamous cell carcinoma of the lung. PMID:16006773

  8. Factors that influence the use of safe patient transfer technique in home care service.

    PubMed

    Skoglind-Öhman, Ingegerd; Kjellberg, Katarina

    2011-01-01

    The aim of this pilot study was to explore whether home care service personnel used knowledge and skills in transfer technique in their daily work; knowledge and skills gained by participating in training programmes, and to identify factors that may hinder and support their use. Focus group interviews were held with 2 home care service groups in 2 Swedish towns. Individual interviews were conducted with the personnel's managers, unit leaders and safety representatives. Qualitative content analysis was used. The findings revealed that the personnel tried to use their knowledge and skills. However, there were both hindering and supporting factors for the use of safe work technique. The findings indicate that training programmes in transfer technique should not be implemented as isolated actions without considering the physical environment, the wishes of persons receiving care and their relatives, the work organisation, the safety culture and the role of managers. PMID:22152508

  9. Analysis of spectral radiative heat transfer using discrete exchange factor method

    NASA Astrophysics Data System (ADS)

    Zhang, Yinqiu; Naraghi, M. H. N.

    1993-09-01

    A solution technique is developed for spectral radiative heat-transfer problems. The formulation is based on the discrete exchange factor (DEF) method and uses Edward's (1976) wide band model to obtain spectral data. The results of the analyses of three cases were found to be in excellent agreement with those of the zonal method and differ by less than 5 percent from those of the discrete-ordinates method.

  10. Transfer of spleen cells expanded by T cell growth factor suppresses arthritis induced in rats.

    PubMed Central

    Ogawa, H; Tsunematsu, T

    1987-01-01

    The effects of transfer of T cell growth factor (TCGF)-expanded spleen cells after concanavalin A (Con A) stimulation into syngeneic Lewis rats were studied. The recipient rats were immunized with complete Freund's adjuvant for induction of adjuvant arthritis (AA) or chick type II collagen in incomplete Freund's adjuvant for induction of collagen-induced arthritis (CIA) on day 0. Each of 5 X 10(7) cultured cells without mitogenic stimulation, 2 X 10(7) Con A-stimulated cells, or 1 X 10(7) TCGF-expanded cells cultured for 8 days (4 days X 2 culture cycles) after Con A stimulation was given on days 0 and 7. Both transfers of the cultured cells without stimulation and TCGF-expanded cells markedly diminished the severity of AA and CIA. On the contrary, transfer of Con A-stimulated cells led to no suppressive activity. In addition, transfer to TCGF-expanded cells significantly lowered the titre of anti-type II collagen antibody compared to that of control rats. The transfer of 1 X 10(7) TCGF-expanded cells was optimal for suppressing AA, in terms of cell number. This observation suggests that these cells were much more effective than were the unstimulated cultured cells, for which more than five times the number was required for the same suppressive activity. As far as the phenotypic proportion of helper (W3/13) and suppressor (OX-8) cells is concerned, we found no significant differences between the cultured cell groups and the freshly separated spleen cell group. The precise mechanism of these suppressive effects is the subject of further study. The transfer of TCGF-expanded cells appears to have a potent immunomodulatory effect. PMID:3497743

  11. Direct phylogenetic evidence for lateral transfer of elongation factor-like gene

    PubMed Central

    Kamikawa, Ryoma; Inagaki, Yuji; Sako, Yoshihiko

    2008-01-01

    Genes encoding elongation factor-like (EFL) proteins, which show high similarity to elongation factor-1α (EF-1α), have been found in phylogenetically distantly related eukaryotes. The sporadic distribution of “EFL-containing” lineages within “EF-1α-containing” lineages indirectly, but strongly, suggests lateral gene transfer as the principal driving force in EFL evolution. However, one of the most critical aspects in the above hypothesis, the donor lineages in any putative cases of lateral EFL gene transfer, remained unclear. In this study, we provide direct evidence for lateral transfer of an EFL gene through the analyses of 10 diatom EFL genes. All diatom EFL homologues tightly clustered in phylogenetic analyses, suggesting acquisition of the exogenous EFL gene early in diatom evolution. Our survey additionally identified Thalassiosira pseudonana as a eukaryote bearing EF-1α and EFL genes and secondary EFL gene loss in Phaeodactylum tricornutum, the complete genome of which encodes only the EF-1α gene. Most importantly, the EFL phylogeny recovered a robust grouping of homologues from diatoms, the cercozoan Bigelowiella natans, and the foraminifer Planoglabratella opecularis, with the diatoms nested within the Bigelowiella plus Planoglabratella (Rhizaria) grouping. The particular relationships recovered are further consistent with two characteristic sequence motifs. The best explanation of our data analyses is an EFL gene transfer from a foraminifer to a diatom, the first case in which the donor–recipient relationship was clarified. Finally, based on a reverse transcriptase quantitative PCR assay and the genome information of Thalassiosira and Phaeodactylum, we propose the loss of elongation factor function in Thalassiosira EF-1α. PMID:18458344

  12. Aggregation and Aggregate Carbon in a Forested Southeastern Coastal Plain Spodosol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil aggregation is influenced by the soil environment and is a factor in soil carbon sequestration. Sandy Coastal Plain soils often do not have the clay to promote aggregation nor have been considered soils with high levels of aggregation. This study was conducted to examine the aggregate morpholog...

  13. Heat transfer and friction factors in the ribbed square convergent and divergent channels

    NASA Astrophysics Data System (ADS)

    Lee, M. S.; Ahn, S. W.

    2016-06-01

    Heat transfer and friction factors are reported for the measurements of turbulent flows in the convergent and divergent square channels with one-sided ribbed wall as well as two opposite in-line ribbed walls. The study covers three different hydraulic diameter ratios between inlet and exit at the test section such as Dho/Dhi = 0.75, 1.0, and 1.33 and Reynolds numbers in the range of 25,000-79,000. The channels, composing of ten isolated copper sections in the length of test section of 1 m, have the hydraulic diameter of 87.5 mm for the straight channel (Dho/Dhi = 1.0); the rib height-to-hydraulic diameter is 0.114; the rib pitch-to-height ratio equals 10. On the contrary to public opinion that the friction factor depends on the portion of the ribbed area, the total friction factor in the two opposite ribbed walls are lower than in the one-sided ribbed wall in the divergent channel of Dho/Dhi = 1.33 because the total pressure, summing positive dynamic and negative static pressures, is acted. The results show that the two opposite ribbed divergent channel of Dho/Dhi = 1.33 provides the best heat transfer enhancement and the two opposite ribbed convergent channel of Dho/Dhi = 0.75 provides the worst friction factor enhancement, and the ribbed divergent channels are generally recommended.

  14. Factors and perceptions that influence women's decisions to have a single embryo transferred.

    PubMed

    de Lacey, S; Davies, M; Homan, G; Briggs, N; Norman, R J

    2007-11-01

    The aim of this study was to identify factors that inhibit or promote the adoption of single embryo transfer (SET). A cohort of 163 women patients receiving IVF/intracytoplasmic sperm injection treatment, comprising 87 women choosing SET and 63 women choosing double embryo transfer (DET), were interviewed using a structured questionnaire. The data were compared using logistic regression analysis. Confidence in the chance of pregnancy with SET, younger age and first treatment were predictive of a decision for SET. Preference for a healthy and singleton pregnancy was predictive but perceptions of the incidence or risk of multiple gestation were not. Factors such as a sense of time urgency and past experience of treatment were significant and predictive of diminished choice of SET. The clinic doctor was an important influencing factor. The results of this study confirm that improved pregnancy rates in SET coupled with an official clinic policy to promote SET in younger, first cycle patients influenced many women to choose SET. However, repeated treatment, advancing age and urgency to become pregnant are factors that moderate a woman's choice for SET. PMID:18028744

  15. Mechanisms of Antibiotic Resistance Determined by Resistance-Transfer Factors1

    PubMed Central

    Unowsky, Joel; Rachmeler, Martin

    1966-01-01

    Unowsky, Joel (Northwestern University Medical School, Chicago, Ill.), and Martin Rachmeler. Mechanisms of antibiotic resistance determined by resistance-transfer factors. J. Bacteriol. 92:358–365. 1966.—This study was concerned with the mechanism of expression of drug resistance carried by resistance-transfer (R) factors of two types: fi− (negative fertility inhibition) and fi+ (positive fertility inhibition). The levels of drug resistance determined by R factors used in this study were similar to those reported by other investigators. A new finding was that Escherichia coli carrying the fi− episome was resistant to 150 to 200 μg/ml of streptomycin. The growth kinetics of R factor-containing cells were similar in the presence or absence of streptomycin, chloramphenicol, and tetracycline, but a period of adaptation was necessary before cells began exponential growth in the presence of tetracycline. By use of radioactive antibiotics, it was shown that cells containing the fi− episome were impermeable to tetracycline and streptomycin, whereas cells containing the fi+ episome were impermeable only to chloramphenicol. Cell-free extracts from fi+ and fi− cells were sensitive to the antibiotics tested in the polyuridylic acid-stimulated incorporation of phenylalanine into protein. PMID:16562121

  16. Pheromone-Regulated Expression of Sex Pheromone Plasmid pAD1-Encoded Aggregation Substance Depends on at Least Six Upstream Genes and a cis-Acting, Orientation-Dependent Factor

    PubMed Central

    Muscholl-Silberhorn, Albrecht B.

    2000-01-01

    Conjugative transfer of Enterococcus faecalis-specific sex pheromone plasmids relies on an adhesin, called aggregation substance, to confer a tight cell-to-cell contact between the mating partners. To analyze the dependence of pAD1-encoded aggregation substance, Asa1, on pheromone induction, a variety of upstream fragments were fused to an α-amylase reporter gene, amyL, by use of a novel promoter probe vector, pAMY-em1. For pheromone-regulated α-amylase activity, a total of at least six genes, traB, traC, traA, traE1, orfY, and orf1, are required: TraB efficiently represses asa1 (by a mechanism unrelated to its presumptive function in pheromone shutdown, since a complete shutdown is observed exclusively in the presence of traC); only traC can relieve traB-mediated repression in a pheromone-dependent manner. In addition to traB, traA is required but not sufficient for negative control. Mutational inactivation of traE1, orfY, or orf1, respectively, results in a total loss of α-amylase activity for constructs normally mediating constitutive expression. Inversion of a fragment covering traA, P0, and traE1 without disrupting any gene or control element switches off amyL or asa1 expression, indicating the involvement of a cis-acting, orientation-dependent factor (as had been shown for plasmid pCF10). Unexpectedly, pAD1 represses all pAMY-em1 derivatives in trans, while its own pheromone-dependent functions are unaffected. The discrepancy between the new data and those of former studies defining TraE1 as a trans-acting positive regulator is discussed. PMID:10850999

  17. Response to platelet-activating factor in human platelets stored and aged in plasma. Decrease in aggregation, phosphoinositide turnover, and receptor affinity

    SciTech Connect

    Shukla, S.D.; Morrison, W.J.; Klachko, D.M.

    1989-07-01

    Human platelet concentrates were stored in polyolefin bags at 22 to 24 degrees C on a horizontal shaker for up to 8 days. At different intervals, aliquots of platelet-rich plasma (PRP) were removed aseptically and five variables, i.e., platelet counts, morphology, platelet-activating factor (PAF)-stimulated aggregation, phosphoinositide turnover, and (3H)PAF binding to platelet receptors, were studied. The number of platelets did not change during the 8 days of storage. Scanning electron microscopy of the platelets revealed a gradual morphologic change from biconcave flat discs to irregular, crenated forms. The PAF-induced aggregation of platelets declined with time of storage. A decrease to 50 percent of the Day 1 aggregatory response to PAF was evident on Day 2, and there was a further decline to about 20 percent by Day 6. Similarly, PAF receptor-coupled phosphoinositide turnover, as monitored by 32P incorporation into individual phosphoinositides, decreased dramatically with storage. After 2 to 3 days of storage, the phosphoinositide turnover was reduced to 50 percent of the original response, and it continued to decline to about 25 percent of original response by Day 5 or 6. The binding of (3H)PAF to washed human platelets indicated subtle changes between Days 2 and 4, which became more noticeable by Day 6. These results have raised the possibility of changes in the number of the receptors and/or their affinity for the ligand during storage. We conclude that although the number of platelets was maintained during storage for 8 days, a general deterioration of their responses to PAF occurred at the levels of cell surface receptor, transmembrane signaling (phosphoinositide turnover), and response (aggregation).

  18. 100% Classification Accuracy Considered Harmful: The Normalized Information Transfer Factor Explains the Accuracy Paradox

    PubMed Central

    Valverde-Albacete, Francisco J.; Peláez-Moreno, Carmen

    2014-01-01

    The most widely spread measure of performance, accuracy, suffers from a paradox: predictive models with a given level of accuracy may have greater predictive power than models with higher accuracy. Despite optimizing classification error rate, high accuracy models may fail to capture crucial information transfer in the classification task. We present evidence of this behavior by means of a combinatorial analysis where every possible contingency matrix of 2, 3 and 4 classes classifiers are depicted on the entropy triangle, a more reliable information-theoretic tool for classification assessment. Motivated by this, we develop from first principles a measure of classification performance that takes into consideration the information learned by classifiers. We are then able to obtain the entropy-modulated accuracy (EMA), a pessimistic estimate of the expected accuracy with the influence of the input distribution factored out, and the normalized information transfer factor (NIT), a measure of how efficient is the transmission of information from the input to the output set of classes. The EMA is a more natural measure of classification performance than accuracy when the heuristic to maximize is the transfer of information through the classifier instead of classification error count. The NIT factor measures the effectiveness of the learning process in classifiers and also makes it harder for them to “cheat” using techniques like specialization, while also promoting the interpretability of results. Their use is demonstrated in a mind reading task competition that aims at decoding the identity of a video stimulus based on magnetoencephalography recordings. We show how the EMA and the NIT factor reject rankings based in accuracy, choosing more meaningful and interpretable classifiers. PMID:24427282

  19. 100% classification accuracy considered harmful: the normalized information transfer factor explains the accuracy paradox.

    PubMed

    Valverde-Albacete, Francisco J; Peláez-Moreno, Carmen

    2014-01-01

    The most widely spread measure of performance, accuracy, suffers from a paradox: predictive models with a given level of accuracy may have greater predictive power than models with higher accuracy. Despite optimizing classification error rate, high accuracy models may fail to capture crucial information transfer in the classification task. We present evidence of this behavior by means of a combinatorial analysis where every possible contingency matrix of 2, 3 and 4 classes classifiers are depicted on the entropy triangle, a more reliable information-theoretic tool for classification assessment. Motivated by this, we develop from first principles a measure of classification performance that takes into consideration the information learned by classifiers. We are then able to obtain the entropy-modulated accuracy (EMA), a pessimistic estimate of the expected accuracy with the influence of the input distribution factored out, and the normalized information transfer factor (NIT), a measure of how efficient is the transmission of information from the input to the output set of classes. The EMA is a more natural measure of classification performance than accuracy when the heuristic to maximize is the transfer of information through the classifier instead of classification error count. The NIT factor measures the effectiveness of the learning process in classifiers and also makes it harder for them to "cheat" using techniques like specialization, while also promoting the interpretability of results. Their use is demonstrated in a mind reading task competition that aims at decoding the identity of a video stimulus based on magnetoencephalography recordings. We show how the EMA and the NIT factor reject rankings based in accuracy, choosing more meaningful and interpretable classifiers. PMID:24427282

  20. Holographic characterization of protein aggregates

    NASA Astrophysics Data System (ADS)

    Wang, Chen; Zhong, Xiao; Ruffner, David; Stutt, Alexandra; Philips, Laura; Ward, Michael; Grier, David

    Holographic characterization directly measures the size distribution of subvisible protein aggregates in suspension and offers insights into their morphology. Based on holographic video microscopy, this analytical technique records and interprets holograms of individual aggregates in protein solutions as they flow down a microfluidic channel, without requiring labeling or other exceptional sample preparation. The hologram of an individual protein aggregate is analyzed in real time with the Lorenz-Mie theory of light scattering to measure that aggregate's size and optical properties. Detecting, counting and characterizing subvisible aggregates proceeds fast enough for time-resolved studies, and lends itself to tracking trends in protein aggregation arising from changing environmental factors. No other analytical technique provides such a wealth of particle-resolved characterization data in situ. Holographic characterization promises accelerated development of therapeutic protein formulations, improved process control during manufacturing, and streamlined quality assurance during storage and at the point of use. Mrsec and MRI program of the NSF, Spheryx Inc.

  1. Neutron spectroscopic factors of Ar34 and Ar46 from (p,d) transfer reactions

    NASA Astrophysics Data System (ADS)

    Lee, Jenny; Tsang, M. B.; Bazin, D.; Coupland, D.; Henzl, V.; Henzlova, D.; Kilburn, M.; Lynch, W. G.; Rogers, A. M.; Sanetullaev, A.; Sun, Z. Y.; Youngs, M.; Charity, R. J.; Sobotka, L. G.; Famiano, M.; Hudan, S.; Shapira, D.; O'Malley, P.; Peters, W. A.; Chae, K. Y.; Schmitt, K.

    2011-01-01

    Single-neutron-transfer measurements using (p,d) reactions have been performed at 33 MeV per nucleon with proton-rich Ar34 and neutron-rich Ar46 beams in inverse kinematics. The extracted spectroscopic factors are compared to the large-basis shell-model calculations. Relatively weak quenching of the spectroscopic factors is observed between Ar34 and Ar46. The experimental results suggest that neutron correlations have a weak dependence on the asymmetry of the nucleus over this isotopic region. The present results are consistent with the systematics established from extensive studies of spectroscopic factors and dispersive optical-model analyses of Ca40-49 isotopes. They are, however, inconsistent with the trends obtained in knockout-reaction measurements.

  2. Extracellular Vesicles from Trypanosoma brucei Mediate Virulence Factor Transfer and Cause Host Anemia.

    PubMed

    Szempruch, Anthony J; Sykes, Steven E; Kieft, Rudo; Dennison, Lauren; Becker, Allison C; Gartrell, Anzio; Martin, William J; Nakayasu, Ernesto S; Almeida, Igor C; Hajduk, Stephen L; Harrington, John M

    2016-01-14

    Intercellular communication between parasites and with host cells provides mechanisms for parasite development, immune evasion, and disease pathology. Bloodstream African trypanosomes produce membranous nanotubes that originate from the flagellar membrane and disassociate into free extracellular vesicles (EVs). Trypanosome EVs contain several flagellar proteins that contribute to virulence, and Trypanosoma brucei rhodesiense EVs contain the serum resistance-associated protein (SRA) necessary for human infectivity. T. b. rhodesiense EVs transfer SRA to non-human infectious trypanosomes, allowing evasion of human innate immunity. Trypanosome EVs can also fuse with mammalian erythrocytes, resulting in rapid erythrocyte clearance and anemia. These data indicate that trypanosome EVs are organelles mediating non-hereditary virulence factor transfer and causing host erythrocyte remodeling, inducing anemia. PMID:26771494

  3. [Viral transfer of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in gene therapy].

    PubMed

    Wędrowska, Ewelina; Wandtke, Tomasz; Dyczek, Andrzej; Woźniak, Joanna

    2015-01-01

    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively induces carcinoma cell death through the extrinsic pathway of apoptosis. Preclinical trials of gene therapy have been conducted using viral transfer of the TRAIL transgene into prostate, bladder, breast, kidney, liver, non-small cell lung cancer and also glioblastoma cells. Experiments in vitro demonstrated the extensive apoptosis of target cells as well as frequent disease regression or remission. TRAIL transfer did not show any side effects, opposite to chemotherapy. Encouraging results of TRAIL-related gene therapy were observed in rheumatoid arthritis and type 1 diabetes. Adenoviral vectors (AdV) encoding TRAIL are the most promising tool in anti-tumor therapy. They have undergone numerous modifications by increasing transfection efficiency and transgene expression in target cells. However, only one clinical phase I trial has been performed. AdV encoding the TRAIL transgene caused local inflammation and apoptosis in patients with prostate cancer. PMID:27259213

  4. Transfer of R factors to and between genetically marked sublines of Rhizobium japonicum.

    PubMed

    Kuykendall, L D

    1979-05-01

    Plasmids R1822 and pRD1 of the P-1 incompatibility group, for which Rhizobium japonicum had not previously been shown to serve as host, were introduced into a strain of R. japonicum. Acquisition of R68 and R68.45 plasmids by this Rhizobium was equivocal. Transfer of R1822 from Pseudomonas aeruginosa and of pRD1 from Escherichia coli to R. japonicum was unambiguous, because the exconjugants subsequently cotransferred the three R-factor resistance determinants (kanamycin, tetracycline, and penicillin) between genetically marked sublines of strain I-110. Under optimal conditions the transfer of R1822 and pRD1 occurred at frequencies of approximately 10(-3) in plate matings of strains bearing as many as five dissimilar genetic markers. In matings with R1822 on membrane filters, recombinants were formed at incidences as high as 4%. PMID:114109

  5. Strategic factors in the development of the National Technology Transfer Network

    NASA Technical Reports Server (NTRS)

    Root, Jonathan F.; Stone, Barbara A.

    1993-01-01

    Broad consensus among industry and government leaders has developed over the last decade on the importance of applying the U.S. leadership in research and development (R&D) to strengthen competitiveness in the global marketplace, and thus enhance national prosperity. This consensus has emerged against the backdrop of increasing economic competition, and the dramatic reduction of military threats to national security with the end of the Cold War. This paper reviews the key factors and considerations that shaped - and continue to influence - the development of the Regional Technoloty Transfer Centers (RTTC) and the National Technology Transfer Center (NTTC). Also, the future role of the national network in support of emerging technology policy initiatives will be explored.

  6. Construction aggregates

    USGS Publications Warehouse

    Tepordei, V.V.

    1993-01-01

    Part of a special section on the market performance of industrial minerals in 1992. Production of construction aggregates increased by 4.6 percent in 1992. This increase was due, in part, to the increased funding for transportation and infrastructure projects. The U.S. produced about 1.05 Gt of crushed stone and an estimated 734 Mt of construction sand and gravel in 1992. Demand is expected to increase by about 5 percent in 1993.

  7. Construction aggregates

    USGS Publications Warehouse

    Tepordei, V.V.

    1996-01-01

    Part of the Annual Commodities Review 1995. Production of construction aggregates such as crushed stone and construction sand and gravel showed a marginal increase in 1995. Most of the 1995 increases were due to funding for highway construction work. The major areas of concern to the industry included issues relating to wetlands classification and the classification of crystalline silica as a probable human carcinogen. Despite this, an increase in demand is anticipated for 1996.

  8. Construction aggregates

    USGS Publications Warehouse

    Nelson, T.I.; Bolen, W.P.

    2007-01-01

    Construction aggregates, primarily stone, sand and gravel, are recovered from widespread naturally occurring mineral deposits and processed for use primarily in the construction industry. They are mined, crushed, sorted by size and sold loose or combined with portland cement or asphaltic cement to make concrete products to build roads, houses, buildings, and other structures. Much smaller quantities are used in agriculture, cement manufacture, chemical and metallurgical processes, glass production and many other products.

  9. Growth factor enhanced retroviral gene transfer to the adult central nervous system.

    PubMed

    King, L A; Mitrophanous, K A; Clark, L A; Kim, V N; Rohll, J B; Kingsman, A J; Colello, R J

    2000-07-01

    The use of viral vectors for gene delivery into mammalian cells provides a new approach in the treatment of many human diseases. The first viral vector approved for human clinical trials was murine leukemia virus (MLV), which remains the most commonly used vector in clinical trials to date. However, the application of MLV vectors is limited since MLV requires cells to be actively dividing in order for transduction and therefore gene delivery to occur. This limitation precludes the use of MLV for delivering genes to the adult CNS, where very little cell division is occurring. However, we speculated that this inherent limitation of ML V may be overcome by utilizing the known mitogenic effect of growth factors on cells of the CNS. Specifically, an in vivo application of growth factor to the adult brain, if able to induce cell division, could enhance MLV-based gene transfer to the adult brain. We now show that an exogenous application of basic fibroblast growth factor induces cell division in vivo. Under these conditions, where cells of the adult brain are stimulated to divide, MLV-based gene transfer is significantly enhanced. This novel approach precludes any vector modifications and provides a simple and effective way of delivering genes to cells of the adult brain utilizing MLV-based retroviral vectors. PMID:10918476

  10. Single-Phase, Turbulent Heat-Transfer Friction-Factor Data Base Flow Enhanced Tb

    1994-01-21

    Heat-exchanger designers need to know what type of performance improvement can be obtained before they will consider enhanced tubes. In particular, they need access to the heat-transfer coefficients and friction-factor values of enhanced tube types that are commercially available. To compile these data from the numerous publications and reports in the open literature is a formidable task that can discourage the designer from using them. A computer program that contains a comprehensive data base withmore » a search feature would be a handy tool for the designer to obtain an estimate of the performance improvement that can be obtained with a particular enhanced tube geometry. In addition, it would be a valuable tool for researchers who are developing and/or validating new prediction methods. This computer program can be used to obtain friction-factor and/or heat-transfer data for a broad range of internally enhanced tube geometries with forced-convective turbulent flow. The program has search features; that is the user can select data for tubes with a particular enhancement geometry range or data obtained from a particular source or publication. The friction factor data base contains nearly 5,000 points and the heat-transfer data base contains more than 4,700 points. About 360 different tube geometries are included from the 36 different sources. Data for tubes with similar geometries and the same and/or different types can be easily extracted with the sort feature of this data base and compared. Users of the program are heat-exchanger designers, enhanced tubing suppliers, and research organizations or academia who are developing or validating prediction methods.« less

  11. Interhospital transfer: an independent risk factor for mortality in the surgical intensive care unit.

    PubMed

    Arthur, Katherine R; Kelz, Rachel R; Mills, Angela M; Reinke, Caroline E; Robertson, Mathew P; Sims, Carrie A; Pascual, Jose L; Reilly, Patrick M; Holena, Daniel N

    2013-09-01

    Interhospital transfer (IHT) is associated with mortality in medical and mixed intensive care units (ICUs), but few studies have examined this relationship in a surgical ICU (SICU) setting. We hypothesized that IHT is associated with increased mortality in SICU patients relative to ICU patients admitted within the hospital. We reviewed SICU and transfer center databases from a tertiary academic center over a 2-year period. Inclusion criteria included age 18 years or older and SICU admission 24 hours or greater. Demographic data, admission service, and Acute Physiology and Chronic Health Evaluation (APACHE) II scores were captured. The primary end point was ICU mortality. Univariate logistic regression was used to test the association between variables and mortality. Factors found to be associated with mortality at P < 0.1 were entered into a multivariable model. Of 4542 admissions, 416 arrived by IHT. Compared with the non-IHT group, the IHT group was older (age 58.3 years [interquartile range, 47.8 to 70.6] vs. 57.8 years [interquartile range, 44.1 to 68.8] years, P = 0.036), sicker (APACHE II score 16.5 [interquartile range, 12 to 23] vs. 14 [interquartile range, 10 to 20], P < 0.001), and more likely to be white (82% [n = 341] vs. 69% [n = 2865], P < 0.001). Mortality rates in IHT patients were highest on the emergency surgery (18%), transplant surgery (16%), and gastrointestinal surgery (8%) services. After adjusting for age and APACHE II score, IHT remained a risk factor for ICU mortality (odds ratio, 1.60; 95% confidence interval, 1.04 to 2.45; P = 0.032) in SICU patients. Interhospital transfer is an independent risk factor for mortality in the SICU population; this risk is unevenly distributed through service lines. Further efforts to determine the cause of this association are warranted. PMID:24069990

  12. Intermedia transfer factors for fifteen toxic pollutants released to air basins in California

    SciTech Connect

    McKone, T.E.; Daniels, J.I.; Chiao, F.F.; Hsieh, D.P.H.

    1993-10-01

    This report provides a summary definition of the intermedia-transfer factors (ITFs). Methods are discussed for estimating these parameters in the absence of measured values, and the estimation errors inherent in these estimation methods are considered. A detailed summary is provided of measured and estimated ITF values for fifteen air contaminants. They include: 1,3 butadiene; cadmium; cellosolve; cellosolve acetate; chloroform; di-2-ethylhexylphthalate; 1,4-dioxame; hexachlorobenzene; inorganic arsenic; inorganic lead; nickel; tetrachloroethylene; toluene; toluene-2,4-diisocyanate; and 1,3-xylene. Recommendations are made regarding the expected value and variance in these values for use in exposure models.

  13. Selection of terrestrial transfer factors for radioecological assessment models and regulatory guides

    SciTech Connect

    Ng, Y.C.; Hoffman, F.O.

    1983-01-01

    A parameter value for a radioecological assessment model is not a single value but a distribution of values about a central value. The sources that contribute to the variability of transfer factors to predict foodchain transport of radionuclides are enumerated. Knowledge of these sources, judgement in interpreting the available data, consideration of collateral information, and established criteria that specify the desired level of conservatism in the resulting predictions are essential elements when selecting appropriate parameter values for radioecological assessment models and regulatory guides. 39 references, 4 figures, 5 tables.

  14. Measurement of the Electric Form Factor of the Neutron at High Momentum Transfer

    SciTech Connect

    Jonathan Miller

    2009-06-01

    The E02-013 collaboration's precision measurement of the electric form factor of the neutron at high momentum took place in Hall A of Jefferson Laboratory [1]. Four kinematic points spread in Q2 from 1.2 to 3.5 (GeV/c)2 reach the region of momentum transfer where there is little ambiguity that the form factors are dominated by the valence quarks. The electric form factor provides important constraints on the generalized parton distributions (GPDs) of the nucleon and therefore to understand the currently unknown quark angular orbital moments. The talk presented newly obtained results for GnE including at Q2 of 2.5 (GeV/c)2. These measurements provide access to twice the range of momentum transfer for complete iso-spin decomposition of the nucleon form factors. The form factors of the u and d quarks were also presented. The measurement used a double polarization asymmetry method [2][3] with He polarized up to 55% (provided by a novel hybrid alkali optical pumping scheme utilizing a Rb & K mixture) and the highly polarized (85%) electron beam at CEBAF. A specially constructed detector package consisting of an electron spectrometer, named Big-Bite, with a solid angle of 95 msr and a large neutron detector were used to detect the particles in the reaction {sup 3}H{rvec e}({rvec e},e',h). The experimental apparatus provided more than 100 times better Figure-of-Merit than other GnE experiments utilizing polarized targets; for more information see [4].

  15. Examining the Factor Structure and Predictive Ability of the German-Version of the Learning Transfer Systems Inventory

    ERIC Educational Resources Information Center

    Bates, Reid; Kauffeld, Simone; Holton, Elwood F., III

    2007-01-01

    Purpose: The purpose of this research is to examine the construct and predictive ability of a German version of the Learning Transfer Systems Inventory (GLTSI), an instrument designed to assess a constellation of 16 factors known to influence the transfer of training in work settings. Design/methodology/approach: The survey data for this study was…

  16. Studies on soil to grass transfer factor (Fv) and grass to milk transfer coefficient (Fm) for cesium in Kaiga region.

    PubMed

    Karunakara, N; Ujwal, P; Yashodhara, I; Rao, Chetan; Sudeep Kumara, K; Dileep, B N; Ravi, P M

    2013-10-01

    Detailed studies were carried out to establish site-specific soil to grass transfer factors (Fv) and grass to cow milk transfer coefficients (Fm) for radioactive cesium ((137)Cs) and stable cesium (Cs) for Kaiga region, where a nuclear power station has been in operation for more than 10 years. The study included adopted cows, cows of local farmers, and cows from the dairy farm. A grass field was developed specifically for the study and 2 local breed cows were adopted and allowed to graze in this grass field. The soil and grass samples were collected regularly from this field and analyzed for the concentrations of (137)Cs and stable Cs to evaluate the soil to grass Fv values. The milk samples from the adopted cows were analyzed for the (137)Cs and stable Cs concentrations to evaluate Fm values. For comparison, studies were also carried out in dominant grazing areas in different villages around the nuclear power plant and the cows of local farmers which graze in these areas were identified and milk samples were collected and analyzed regularly. The geometric mean values of Fv were found to be 1.1 × 10(-1) and 1.8 × 10(-1) for (137)Cs and stable Cs, respectively. The Fm of (137)Cs had geometric mean values of 1.9 × 10(-2) d L(-1) and 4.6 × 10(-2) d L(-1), respectively, for adopted Cows 1 and 2; 1.7 × 10(-2) d L(-1) for the cows of local farmers, and 4.0 × 10(-3) d L(-1) for the dairy farm cows. The geometric mean values of Fm for stable Cs were similar to those of (137)Cs. The Fm value for the dairy farm cows was an order of magnitude lower than those for local breed cows. The Fm values observed for the local breed cows were also an order of magnitude higher when compared to the many values reported in the literature and in the IAEA publication. Possible reasons for this higher Fm values were identified. The correlation between Fv and Fm values for (137)Cs and stable Cs and their dependence on the potassium content ((40)K and stable K) in

  17. Effect of alcohol aggregation on the retention factors of chiral solutes with an amylose-based sorbent: modeling and implications for the adsorption mechanism.

    PubMed

    Tsui, Hung-Wei; Franses, Elias I; Wang, Nien-Hwa Linda

    2014-02-01

    Various displacement models in the literature have been widely used for understanding the adsorption mechanisms of solutes in various chromatography systems. The models were used for describing the often-observed linear plots of the logarithms of the retention factor versus the logarithms of the polar modifier concentration CI(0). The slopes of such a plot was inferred to be equal to the number of the displaced modifier molecules upon adsorption of one solute molecule, and were generally found to be greater than 1. In this study, the retention factors of four structurally related chiral solutes, ethyl lactate (EL), methyl mandelate (MM), benzoin (B), and pantolactone (PL), were measured for the amylose tris[(S)-α-methylbenzylcarbamate] sorbent, or AS, as a function of the concentration of isopropanol (IPA) in n-hexane. With increasing IPA concentration CI(0), the slopes increase from less than 1, at a concentration range from 0.13 to 1.3M, to slightly more than 1 at higher concentrations. Such slopes cannot be explained by the conventional retention models. It was found previously for monovalent solutes that such slopes can only be explained when the aggregation of the mobile phase modifier, isopropyl alcohol, was accounted for. A new retention model is presented here, accounting for alcohol aggregation, multivalent solute adsorption, multivalent solute-alcohol complexation, alcohol adsorption, and solute intra hydrogen-bonding, which occur in these four solutes. The slope is found to be controlled by three key dimensionless groups, the fraction of the sorbent binding sites covered by IPA, the fraction of the solute molecules in complex form, and the fraction of the IPA molecules in aggregate form. The limiting slope at a very high IPA concentration is equal to the value of (x+y)/n, where x is the number of the solute-sorbent binding sites and y is the number of the alcohol molecules in the solute-alcohol complex, and n is the alcohol aggregation number. The model

  18. Literature Review and Assessment of Plant and Animal Transfer Factors Used in Performance Assessment Modeling

    SciTech Connect

    Robertson, David E.; Cataldo, Dominic A.; Napier, Bruce A.; Krupka, Kenneth M.; Sasser, Lyle B.

    2003-07-20

    A literature review and assessment was conducted by Pacific Northwest National Laboratory (PNNL) to update information on plant and animal radionuclide transfer factors used in performance-assessment modeling. A group of 15 radionuclides was included in this review and assessment. The review is composed of four main sections, not including the Introduction. Section 2.0 provides a review of the critically important issue of physicochemical speciation and geochemistry of the radionuclides in natural soil-water systems as it relates to the bioavailability of the radionuclides. Section 3.0 provides an updated review of the parameters of importance in the uptake of radionuclides by plants, including root uptake via the soil-groundwater system and foliar uptake due to overhead irrigation. Section 3.0 also provides a compilation of concentration ratios (CRs) for soil-to-plant uptake for the 15 selected radionuclides. Section 4.0 provides an updated review on radionuclide uptake data for animal products related to absorption, homeostatic control, approach to equilibration, chemical and physical form, diet, and age. Compiled transfer coefficients are provided for cow’s milk, sheep’s milk, goat’s milk, beef, goat meat, pork, poultry, and eggs. Section 5.0 discusses the use of transfer coefficients in soil, plant, and animal modeling using regulatory models for evaluating radioactive waste disposal or decommissioned sites. Each section makes specific suggestions for future research in its area.

  19. Driving Cartilage Formation in High-Density Human Adipose-Derived Stem Cell Aggregate and Sheet Constructs Without Exogenous Growth Factor Delivery

    PubMed Central

    Dang, Phuong N.; Solorio, Loran D.

    2014-01-01

    An attractive cell source for cartilage tissue engineering, human adipose-derived stem cells (hASCs) can be easily expanded and signaled to differentiate into chondrocytes. This study explores the influence of growth factor distribution and release kinetics on cartilage formation within 3D hASC constructs incorporated with transforming growth factor-β1 (TGF-β1)-loaded gelatin microspheres. The amounts of microspheres, TGF-β1 concentration, and polymer degradation rate were varied within hASC aggregates. Microsphere and TGF-β1 loading concentrations were identified that resulted in glycosaminoglycan (GAG) production comparable to those of control aggregates cultured in TGF-β1-containing medium. Self-assembling hASC sheets were then engineered for the production of larger, more clinically relevant constructs. Chondrogenesis was observed in hASC-only sheets cultured with exogenous TGF-β1 at 3 weeks. Importantly, sheets with incorporated TGF-β1-loaded microspheres achieved GAG production similar to sheets treated with exogenous TGF-β1. Cartilage formation was confirmed histologically via observation of cartilage-like morphology and GAG staining. This is the first demonstration of the self-assembly of hASCs into high-density cell sheets capable of forming cartilage in the presence of exogenous TGF-β1 or with TGF-β1-releasing microspheres. Microsphere incorporation may bypass the need for extended in vitro culture, potentially enabling hASC sheets to be implanted more rapidly into defects to regenerate cartilage in vivo. PMID:24873753

  20. Isolation and cloning of a C-type lectin from the hexactinellid sponge Aphrocallistes vastus: a putative aggregation factor.

    PubMed

    Gundacker, D; Leys, S P; Schröder, H C; Müller, I M; Müller, W E

    2001-01-01

    Among the sponges (Porifera), the oldest group of metazoans in phylogenetic terms, the Hexactinellida is considered to have diverged earliest from the two other sponge classes, the Demospongiae and Calcarea. The Hexactinellida are unusual among all Metazoa in possessing mostly syncytial rather than cellular tissues. Here we describe the purification of a cell adhesion molecule with a size of 34 kDa (in its native form; 24 kDa after deglycosylation) from the hexactinellid sponge Aphrocallistes vastus. This adhesion molecule was previously found to agglutinate preserved cells and membranes in a non-species-specific manner (Müller, W. E. G., Zahn, R. K, Conrad, J., Kurelec, B., and Uhlenbruck, G. [1984] Cell adhesion molecules in the haxactinellid Aphrocallistes vastus: species-unspecific aggregationfactor. Differentiation, 26, 30--35). The fact that the aggregation process required Ca(2+) and was inhibited by bird's nest glycoprotein and D-galactose but not by D-mannose or N-acetyl-D-galactosamine suggests that this cell adhesion molecule is a C-type lectin. To test this assumption, two highly similar C-type lectins were cloned from A.vastus. The deduced polypeptides of the two cDNA species isolated classified these molecules as C-type lectins. The calculated M(r) of the 191 aa long sequences were 22,022 and 22,064, respectively. The C-type lectins showed highest similarity to C-type lectins (type-II membrane proteins) from higher metazoan phyla; these molecules are absent in non-Metazoa. The two sponge C-type lectins contain the conserved domains known from other C-type lectins (e.g., disulfide bonds, the amino acids known to be involved in Ca(2+)-binding, as well as the amino acids involved in the specificity of binding to D-galactose) and a hydrophobic N-terminal region. The N-terminal part of the purified C-type lectin was identical with the corresponding region of the deduced polypeptide from the cDNA. It is proposed that the A.vastus lectins might bind to the

  1. Neutron spectroscopic factors of 55Ni hole-states from (p,d) transfer reactions

    NASA Astrophysics Data System (ADS)

    Sanetullaev, A.; Tsang, M. B.; Lynch, W. G.; Lee, Jenny; Bazin, D.; Chan, K. P.; Coupland, D.; Henzl, V.; Henzlova, D.; Kilburn, M.; Rogers, A. M.; Sun, Z. Y.; Youngs, M.; Charity, R. J.; Sobotka, L. G.; Famiano, M.; Hudan, S.; Shapira, D.; Peters, W. A.; Barbieri, C.; Hjorth-Jensen, M.; Horoi, M.; Otsuka, T.; Suzuki, T.; Utsuno, Y.

    2014-09-01

    Spectroscopic information has been extracted on the hole-states of 55Ni, the least known of the quartet of nuclei (55Ni, 57Ni, 55Co and 57Cu), one nucleon away from 56Ni, the N=Z=28 double magic nucleus. Using the H1(Ni56,d)Ni55 transfer reaction in inverse kinematics, neutron spectroscopic factors, spins and parities have been extracted for the f7/2, p3/2 and the s1/2 hole-states of 55Ni. These new data provide a benchmark for large basis calculations that include nucleonic orbits in both the sd and pf shells. State of the art calculations have been performed to describe the excitation energies and spectroscopic factors of the s1/2 hole-state below Fermi energy.

  2. Heat Transfer and Friction-Factor Methods Turbulent Flow Inside Pipes 3d Rough

    1994-01-21

    Three-dimensional roughened internally enhanced tubes have been shown to be one of the most energy efficient for turbulent, forced convection applications. However, there is only one prediction method presented in the open literature and that is restricted to three-dimensional sand-grain roughness. Other roughness types are being proposed: hemispherical sectors, truncated cones, and full and truncated pyramids. There are no validated heat-transfer and friction-factor prediction methods for these different roughness shapes that can be used inmore » the transition and fully rough region. This program calculates the Nusselt number and friction factor values, for a broad range of three-dimensional roughness types such as hemispherical sectors, truncated cones, and full and truncated pyramids. Users of this program are heat-exchangers designers, enhanced tubing suppliers, and research organizations or academia who are developing or validating prediction methods.« less

  3. Construction aggregates

    USGS Publications Warehouse

    Bolen, W.P.; Tepordei, V.V.

    2001-01-01

    The estimated production during 2000 of construction aggregates, crushed stone, and construction sand and gravel increased by about 2.6% to 2.7 Gt (3 billion st), compared with 1999. The expansion that started in 1992 continued with record production levels for the ninth consecutive year. By commodity, construction sand and gravel production increased by 4.5% to 1.16 Gt (1.28 billion st), while crushed stone production increased by 1.3% to 1.56 Gt (1.72 billion st).

  4. Do maise and wheat chloroplast protein synthesis elongation factor, EF-Tu, protect Rubisco activase from thermal aggregation and inactivation?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize (Zea mays L.) chloroplast protein synthesis elongation factor, EF-Tu, has been implicated in the development of heat tolerance. The precursor of this protein (pre-EF-Tu) has been shown to display chaperone activity, as it protected heat labile citrate synthase and malate dehydrogenase from the...

  5. Statistical iterative reconstruction using fast optimization transfer algorithm with successively increasing factor in Digital Breast Tomosynthesis

    NASA Astrophysics Data System (ADS)

    Xu, Shiyu; Zhang, Zhenxi; Chen, Ying

    2014-03-01

    Statistical iterative reconstruction exhibits particularly promising since it provides the flexibility of accurate physical noise modeling and geometric system description in transmission tomography system. However, to solve the objective function is computationally intensive compared to analytical reconstruction methods due to multiple iterations needed for convergence and each iteration involving forward/back-projections by using a complex geometric system model. Optimization transfer (OT) is a general algorithm converting a high dimensional optimization to a parallel 1-D update. OT-based algorithm provides a monotonic convergence and a parallel computing framework but slower convergence rate especially around the global optimal. Based on an indirect estimation on the spectrum of the OT convergence rate matrix, we proposed a successively increasing factor- scaled optimization transfer (OT) algorithm to seek an optimal step size for a faster rate. Compared to a representative OT based method such as separable parabolic surrogate with pre-computed curvature (PC-SPS), our algorithm provides comparable image quality (IQ) with fewer iterations. Each iteration retains a similar computational cost to PC-SPS. The initial experiment with a simulated Digital Breast Tomosynthesis (DBT) system shows that a total 40% computing time is saved by the proposed algorithm. In general, the successively increasing factor-scaled OT exhibits a tremendous potential to be a iterative method with a parallel computation, a monotonic and global convergence with fast rate.

  6. Dis-aggregation of an insoluble porphyrin in a calixarene matrix: characterization of aggregate modes by extended dipole model.

    PubMed

    de Miguel, Gustavo; Martín-Romero, María T; Pedrosa, José M; Muñoz, Eulogia; Pérez-Morales, Marta; Richardson, Tim H; Camacho, Luis

    2008-03-21

    In this paper, the different aggregation modes of a water-insoluble porphyrin (EHO) mixed with an amphiphilic calix[8]arene (C8A), at the air-water interface and in Langmuir-Blodgett (LB) film form, are analyzed as a function of the mixed composition. The strategy used to control the EHO aggregation has consisted of preparing mixed thin films containing EHO and C8A, in different ratios, at the air-water interface. Therefore, the increase of the C8A molar ratio in the mixed film diminishes the aggregation of the EHO molecules, although such an effect must be exclusively related to the dilution of the porphyrin. The reflection spectra of the mixed C8A-EHO films registered at the air-water interface, show a complex Soret band exhibiting splitting, hypochromicity and broadening features. Also, during the transfer process at high surface pressure, it has been shown that the EHO molecules are ejected from the C8A monolayer and only a fraction of porphyrin is transferred to the solid support, in spite of a complete transfer for the C8A matrix. The complex structure of the reflection spectra at the air-water interface, as well as the polarization dependence of the absorption spectra for the mixed LB films, indicate the existence of four different arrangements for the EHO hosted in the C8A matrix. The aggregate formation is governed by two factors: the attraction between the porphyrin rings which minimizes their separation, and the alkyl chain interactions, that is, hydrophobic effect and/or steric hindrance which determine and restrict the possible aggregation structures. By using the extended dipole model, the assignment of the spectral peaks observed to different EHO aggregates is shown. PMID:18327313

  7. The Time-Dependent Transfer Factor of Radiocesium from Soil to Game Animals in Japan after the Fukushima Dai-ichi Nuclear Accident.

    PubMed

    Tagami, Keiko; Howard, Brenda J; Uchida, Shigeo

    2016-09-01

    Since the Fukushima Dai-ichi accident, monitoring of tissues from hunted game animals ensures compliance with the standard food limits for radionuclides in Japan. We quantified the transfer of (137)Cs from contaminated land to game animals using the Aggregated transfer factor (Tag = activity concentration in meat [Bq kg(-1) fw]/amount in soil [Bq m(-2)]) of (137)Cs for Asian black bear, wild boar, sika deer, green pheasant, copper pheasant and wild duck, collected between 2011 and 2015. Open data sources were used from Fukushima, Miyagi, Ibaraki, Tochigi, and Gunma prefectures. Our initially compiled data showed that the maximum reported (137)Cs activity concentration in wild boar after the Fukushima Dai-ichi accident were lower than those reported after the Chernobyl accident. The geometric mean Tag values (m(2)kg(-1) fw) of (137)Cs in 2015 for Asian black bear, wild boar, sika deer and copper pheasant were similar (1.9-5.1) × 10(-3) while those for green pheasant and wild duck were about 1 order of magnitude lower at (1.0-2.2) × 10(-4). Effective half-lives were 1.2-6.9 y except for sika deer and copper pheasant where no decreases were found. In contrast to the Chernobyl accident, no seasonal change occurred in the meat (137)Cs activity concentrations of the wild animals during the study period. PMID:27513196

  8. Perception of Lay People Regarding Determinants of Health and Factors Affecting It: An Aggregated Analysis from 29 Countries

    PubMed Central

    ZAHRA, Aqeela; LEE, Eun-Whan; SUN, Li-Yuan; PARK, Jae-Hyun

    2015-01-01

    Background: This study aimed to evaluate the perception of lay people regarding determinants of health at global level and factors affecting it. Methods: Data was collected from International Social Survey Program (ISSP) and World Bank website. Multilevel regression analysis was done and lay people’s perception regarding health behavior, environment, poverty and genes as health determinants was assessed. Various socio demographic factors were used as independent variables. Results: The highest percentage of people agreed environment as determinant of health. An inverse relationship was observed between GNI quartiles and an individual’s agreement with poverty, health behavior, and environment as health determinant. There was a significant negative association of females with health damaging behavior (P<0.05) and positive association with environment and genes (P<0.05) as health determinants. Elderly people agreed with poverty as determinant of health (P<0.05). GNI was negatively related to environment (P<0.05) and poverty (P<0.05) as health determinant. Conclusion: The common public is now becoming aware of a broadened concept of health and people belonging to different backgrounds have different perceptions regarding determinants of health. Our results show that highest percentage of people agreed with environment as determinant of health, which is consistent with scientific view of increased burden of disease, caused by environmental factors. Thus, tailored health programs and policies that address an individual’s specific problems are likely to induce a change in behavior and attitude, hence decreasing the disease burden. PMID:26811813

  9. Foliar transfer into the biosphere: review of translocation factors to cereal grains.

    PubMed

    Colle, C; Madoz-Escande, C; Leclerc, E

    2009-09-01

    A review of the published literature about foliar transfer radionuclides to cereal grains was carried out with a special interest for translocation factors. Translocation describes the distribution of radionuclides within the plant after foliar deposition and radionuclide absorption onto the surface of leaves. It mainly depends on elements and the plant growth stage. The collected data were derived from both in-field and greenhouse experiments. They were analysed in order to select those coming from a contamination simulating a sprinkling irrigation or a rain. The data set contains 307 values. For each radionuclide the translocation factor values were sorted according to 5 characteristic stages of the cereal vegetative cycle: leaf development-tillering, stem elongation, earing-flowering, grain growth and ripening. Wheat, barley and rye have been treated together, independently of rice. For mobile elements such as cesium, the translocation factor is maximum when the contamination occurred at the earing-flowering stage. For less mobile elements such as strontium this maximum occurred for a foliar contamination at the grain growth stage. This review enabled us to propose the most probable value as well as the range of variation of translocation factors for some radionuclides according to the cereal vegetative cycle. Moreover, from these results, a radionuclide classification is proposed according to three mobility groups. PMID:19019504

  10. Isolation, cDNA cloning, and characterization of an 18-kDa hemagglutinin and amebocyte aggregation factor from Limulus polyphemus.

    PubMed

    Fujii, N; Minetti, C A; Nakhasi, H L; Chen, S W; Barbehenn, E; Nunes, P H; Nguyen, N Y

    1992-11-01

    characterized hemagglutinin has been termed Limulus 18K agglutination-aggregation factor (18K-LAF). PMID:1429596

  11. Transfer factors as immunotherapy and supplement of chemotherapy in experimental pulmonary tuberculosis

    PubMed Central

    FABRE, R A; PÉREZ, T M; AGUILAR, L D; RANGEL, M J; ESTRADA-GARCÌA, I; HERNÁNDEZ-PANDO, R; ESTRADA PARRA, S

    2004-01-01

    Problems of logistics, compliance and drug resistance point to an urgent need for immunotherapeutic strategies capable of shortening the current six month antibiotic regimens used to treat tuberculosis. One potential immunotherapeutic agent is transfer factors. Transfer factors (TF) are low molecular weight dialysable products from immune cells which transmit the ability to express delayed-type hypersensitivity (DTH) and cell mediated immunity from sensitized donors to nonimmune recipients. In this study we determined the efficiency of TF as immunotherapy to treat experimental tuberculosis. When BALB/c mice are infected via the trachea with Mycobacterium tuberculosis H37Rv there is an initial phase of partial resistance dominated by Th-1 type cytokines plus tumour necrosis factor-alpha (TNFα) and the inducible isoform of nitric oxide synthase (iNOS), followed by a phase of progressive disease characterized by increasing expression of IL-4, diminished expression of TNFα and iNOS, and low DTH. Animals in this late progressive phase of the disease (day 60) were treated with different doses of TF (one injection per week) obtained from spleen cells when the peak of immune protection in this animal model is reached (day 21), or with different doses of TF from peripheral leucocytes of PPD + healthy subjects. We show here that the treatment with murine or human TF restored the expression of Th-1 cytokines, TNFα and iNOS provoking inhibition of bacterial proliferation and significant increase of DTH and survival. This beneficial effect was dose dependent. Interestingly, murine TF in combination with conventional chemotherapy had a synergistic effect producing significant faster elimination of lung bacteria loads than chemotherapy alone. PMID:15086383

  12. Improved Induction of Immune Tolerance to Factor IX by Hepatic AAV-8 Gene Transfer

    PubMed Central

    Cooper, Mario; Nayak, Sushrusha; Hoffman, Brad E.; Terhorst, Cox; Cao, Ou

    2009-01-01

    Abstract Gene therapy for hemophilia B has been shown to result in long-term expression and immune tolerance to factor IX (F.IX) after in vivo transduction of hepatocytes with adeno-associated viral (AAV-2) vectors in experimental animals. An optimized protocol was effective in several strains of mice with a factor 9 gene deletion (F9−/−). However, immune responses against F.IX were repeatedly observed in C3H/HeJ F9−/− mice. We sought to establish a gene transfer protocol that results in sustained expression without a requirement for additional manipulation of the immune system. Compared with AAV-2, AAV-8 was more efficient in transgene expression and induction of tolerance to F.IX in three different strains of wild-type mice. At equal vector doses, AAV-8 induced transgene product-specific regulatory CD4+CD25+FoxP3+ T cells at significantly higher frequency. Moreover, sustained correction of hemophilia B in C3H/HeJ F9−/− mice without antibody formation was documented in all animals treated with ≥4 × 1011 vector genomes (VG)/kg and in 80% of mice treated with 8 × 1010 VG/kg. Therefore, it is possible to develop a gene transfer protocol that reliably induces tolerance to F.IX largely independent of genetic factors. A comparison with other studies suggests that additional parameters besides plateau levels of F.IX expression contributed to the improved success rate of tolerance induction. PMID:19309290

  13. From Dark to Light to Fluorescence Resonance Energy Transfer (FRET): Polarity-Sensitive Aggregation-Induced Emission (AIE)-Active Tetraphenylethene-Fused BODIPY Dyes with a Very Large Pseudo-Stokes Shift.

    PubMed

    Şen, Esra; Meral, Kadem; Atılgan, Serdar

    2016-01-11

    The work presented herein is devoted to the fabrication of large Stokes shift dyes in both organic and aqueous media by combining dark resonance energy transfer (DRET) and fluorescence resonance energy transfer (FRET) in one donor-acceptor system. In this respect, a series of donor-acceptor architectures of 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) dyes substituted by one, two, or three tetraphenylethene (TPE) luminogens were designed and synthesised. The photophysical properties of these three chromophore systems were studied to provide insight into the nature of donor-acceptor interactions in both THF and aqueous media. Because the generation of emissive TPE donor(s) is strongly polarity dependent, due to its aggregation-induced emission (AIE) feature, one might expect the formation of appreciable fluorescence emission intensity with a very large pseudo-Stokes shift in aqueous media when considering FRET process. Interestingly, similar results were also recorded in THF for the chromophore systems, although the TPE fragment(s) of the dyes are non-emissive. The explanation for this photophysical behaviour lies in the DRET. This is the first report on combining two energy-transfer processes, namely, FRET and DRET, in one polarity-sensitive donor-acceptor pair system. The accuracy of the dark-emissive donor property of the TPE luminogen is also presented for the first time as a new feature for AIE phenomena. PMID:26617068

  14. Chemical elements in pearl oysters (Paxyodon ponderosus), phytoplankton and estuarine sediments from eastern Amazon (Northern Brazil): Bioaccumulation factors and trophic transfer factors

    NASA Astrophysics Data System (ADS)

    Vilhena, Maria P. S. P.; Costa, Marcondes L.; Berrêdo, José F.; Paiva, Rosildo S.; Souza, Crisvaldo C. S.

    2016-04-01

    The current study was conducted near Barcarena County, which is a mid-sized urban center where aluminum ore processing industries (bauxite) and Vila do Conde cargo terminal are located. It aims to discuss the bioaccumulation factors as well as factors related to the trophic transfer of chemical elements in water, oyster, phytoplankton and bottom sediments from an estuary in the Brazilian Northern coast. The bioaccumulation factor (BAF), trophic transfer factor (TTF) and biota-sediment-water were used to correlate the contents of chemical elements found in organisms. The sediment, surface water, phytoplankton and pearl oysters chemical composition was analyzed by ICP-OES and ICP-MS. Pearl oysters showed K, Ca, Mg, P, Mn, Fe, Zn, Al, Ba and Pb accumulation, which concentration increase is associated with their diet (phytoplankton). Al concentrations are 14 times higher in pearl oysters (Paxyodon ponderosus), assuming that they are associated with wastewater emissions and with industrialization processes in the area. BAF and BSAF values are 1000 times higher than the metal concentrations in water and bioavailable fraction concentrations. The oyster-phytoplankton trophic transfer factor indicates that P, Ba, Ca, Na, Cd and Zn showed the largest transfers (from 5 to 19). These trophic transfers may be sufficient to cause significant ecotoxicological effects on the region biota.

  15. Single-Phase Active Boost Rectifier with Power Factor Correction for Wireless Power Transfer Applications

    SciTech Connect

    Chinthavali, Madhu Sudhan; Onar, Omer C; Miller, John M; Tang, Lixin

    2013-01-01

    Wireless Power Transfer (WPT) technology is a novel research area in the charging technology that bridges utility and the automotive industries. There are various solutions that are currently being evaluated by several research teams to find the most efficient way to manage the power flow from the grid to the vehicle energy storage system. There are different control parameters that can be utilized to compensate for the change in the impedance. To understand the power flow through the system this paper presents a novel approach to the system model and the impact of different control parameters on the load power. The implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation is also discussed.

  16. Lifetime and g-factor measurements of excited states using Coulomb excitation and alpha transfer reactions

    NASA Astrophysics Data System (ADS)

    Guevara, Z. E.; Torres, D. A.

    2016-07-01

    In this contribution the challenges in the use of a setup to simultaneously measure lifetimes and g-factor values will be presented. The simultaneous use of the transient field technique and the Doppler Shift Attenuation Method, to measure magnetic moments and lifetimes respectively, allows to obtain a complete characterization of the currents of nucleons and the deformation in excited states close to the ground state. The technique is at the moment limited to Coulomb excitation and alpha-transfer reactions, what opens an interesting perspective to consider this type of experiments with radioactive beams. The use of deep-inelastic and fusion-evaporation reactions will be discussed. An example of a setup that makes use of a beam of 106Cd to study excited states of 110Sn and the beam nuclei itself will be presented.

  17. Biota-sediment accumulation and trophic transfer factors for extremely hydrophobic polychlorinated biphenyls

    SciTech Connect

    Maruya, K.A.; Lee, R.F.

    1998-12-01

    Polychlorinated biphenyls (PCBs) in fish, invertebrates, and sediment from a contaminated tidal creek system in coastal Georgia (USA) were traced to Aroclor 1268, a mixture of hepta through decachlorinated homologs used at a former chlor/alkali plant adjacent to the study site. The base 10 logarithm of the octanol/water partition coefficient (K{sub ow}) for the 15 most abundant Aroclor 1268 components in these samples ranged from 6.7 to >9. The composite mean biota-sediment accumulation factor (BSAF) for these congeners was 3.1, 0.81, and 0.28 for yearling striped mullet, spotted sea trout, and grass shrimp, respectively, species representing three trophic levels of the local food web. Individual congener BSAFs were negatively correlated with log K{sub ow} for all three species. The composite mean trophic transfer factor (TTF{sub lip}), defined as the ratio of lipid-normalized PCB concentrations in fish to grass shrimp, was higher for mullet (12) than for sea trout (2.9). Individual TTF{sub lip} values were two to three times higher for Cl{sub 7} and Cl{sub 8} homologs that were substituted at all four ortho positions, suggesting a difference in PCB retention based on chlorine substitution patterns. The relative magnitude of BSAFs and TTF{sub lip} values indicated that sediment-ingesting forage species like mullet efficiently accumulate PCBs and are an important link in the food web transfer of sediment-ingesting forage in this system. The negative linear relationships between BSAF and log K{sub ow} established in this study are among the first to be reported in the field for extremely hydrophobic PCBs.

  18. Transfer factors of natural radionuclides and (137)Cs from soil to plants used in traditional medicine in central Serbia.

    PubMed

    Djelic, Gorica; Krstic, Dragana; Stajic, Jelena M; Milenkovic, Biljana; Topuzovic, Marina; Nikezic, Dragoslav; Vucic, Dusica; Zeremski, Tijana; Stankovic, Milan; Kostic, Dragana

    2016-07-01

    Transfer factors of natural radionuclides and (137)Cs from soil to plants used in traditional medicine were determined. The transfer factors (TF) were calculated as Bq kg(-1) of dry plant per Bq kg(-1) of dry soil. Mass activity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs in soil and plant samples were measured with high purity germanium detector (HPGe). The concentrations of As, Co, Cr, Cu, Mn, Ni, Pb and Zn were determined, as well as the cation exchange capacity (CEC) and the content of exchangeable cations (Ca, Mg, K, Na). Wide ranges of values were obtained for all the metals, especially for Cr and Ni. The Absalom model was used for determination of the amount of (137)Cs transferred from soil to plant based on soil characteristics such as pH, exchangeable potassium, humus and clay contents. The estimated transfer factors were in the range from 0.011 to 0.307 with an arithmetic mean of 0.071, median of 0.050, geometric mean of 0.053 and geometric standard deviation (GSD) of 2.08. This value agreed well with that calculated from the measurements of 0.069, geometric mean 0.040 and GSD 3.19. Correlations between radionuclides, metals, physicochemical properties and transfer factors were determined by Spearman correlation coefficient. There was a strong positive correlation between (137)Cs transfer factor and the ratio of transfer factor for K and (137)Cs. Principal Component Analysis (PCA) was performed in order to identify some pattern of data. PMID:27082759

  19. Local convective heat transfer coefficient and friction factor of CuO/water nanofluid in a microchannel heat sink

    NASA Astrophysics Data System (ADS)

    Chabi, A. R.; Zarrinabadi, S.; Peyghambarzadeh, S. M.; Hashemabadi, S. H.; Salimi, M.

    2016-06-01

    Forced convective heat transfer in a microchannel heat sink (MCHS) using CuO/water nanofluids with 0.1 and 0.2 vol% as coolant was investigated. The experiments were focused on the heat transfer enhancement in the channel entrance region at Re < 1800. Hydraulic performance of the MCHS was also estimated by measuring friction factor and pressure drop. Results showed that higher convective heat transfer coefficient was obtained at the microchannel entrance. Maximum enhancement of the average heat transfer coefficient compared with deionized water was about 40 % for 0.2 vol% nanofluid at Re = 1150. Enhancement of the convective heat transfer coefficient of nanofluid decreased with further increasing of Reynolds number.

  20. Modification of an impulse-factoring orbital transfer technique to account for orbit determination and maneuver execution errors

    NASA Technical Reports Server (NTRS)

    Kibler, J. F.; Green, R. N.; Young, G. R.; Kelly, M. G.

    1974-01-01

    A method has previously been developed to satisfy terminal rendezvous and intermediate timing constraints for planetary missions involving orbital operations. The method uses impulse factoring in which a two-impulse transfer is divided into three or four impulses which add one or two intermediate orbits. The periods of the intermediate orbits and the number of revolutions in each orbit are varied to satisfy timing constraints. Techniques are developed to retarget the orbital transfer in the presence of orbit-determination and maneuver-execution errors. Sample results indicate that the nominal transfer can be retargeted with little change in either the magnitude (Delta V) or location of the individual impulses. Additonally, the total Delta V required for the retargeted transfer is little different from that required for the nominal transfer. A digital computer program developed to implement the techniques is described.

  1. Direct transfer of transforming growth factor beta 1 gene into arteries stimulates fibrocellular hyperplasia.

    PubMed Central

    Nabel, E G; Shum, L; Pompili, V J; Yang, Z Y; San, H; Shu, H B; Liptay, S; Gold, L; Gordon, D; Derynck, R

    1993-01-01

    The arterial wall responds to thrombosis or mechanical injury through the induction of specific gene products that increase cellular proliferation and connective tissue formation. These changes result in intimal hyperplasia that is observed in restenosis and the early phases of atherosclerosis. Transforming growth factor beta 1 (TGF-beta 1) is a secreted multi-functional protein that plays an important role in embryonal development and in repair following tissue injury. However, the function of TGF-beta 1 in vascular cell growth in vivo has not been defined. In this report, we have evaluated the role of TGF-beta 1 in the pathophysiology of intimal and medial hyperplasia by gene transfer of an expression plasmid encoding active TGF-beta 1 into porcine arteries. Expression of TGF-beta 1 in normal arteries resulted in substantial extracellular matrix production accompanied by intimal and medial hyperplasia. Increased procollagen, collagen, and proteoglycan synthesis in the neointima was demonstrated by immunohistochemistry relative to control transfected arteries. Expression of TGF-beta 1 induced a distinctly different program of gene expression and biologic response from the platelet-derived growth factor B (PDGF B) gene: procollagen synthesis induced by TGF-beta 1 was greater, and cellular proliferation was less prominent. These findings show that TGF-beta 1 differentially modulates extracellular matrix production and cellular proliferation in the arterial wall in vivo and could play a reparative role in the response to arterial injury. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8248168

  2. Transference factors as a tool for the estimation of arsenic milk concentration.

    PubMed

    Pérez-Carrera, Alejo; Alvarez-Gonçalvez, Cristina V; Fernández-Cirelli, Alicia

    2016-08-01

    The Chaco Pampean Plain of central Argentina represents one of the largest regions with high levels of arsenic (As) in groundwater. The aim of this study was the assessment of a biotransference factor (BTF) as a tool for the estimation of As concentration in cow's milk from As drinking water concentration. Total As content in livestock drinking water, soil, forage, and milk was determined in farms located in an area of high As groundwater, in order to analyze the relation between As uptake and its transfer to milk. The concentrations of As in milk ranged from 0.5 to 8.0 μg/L. From the results obtained, drinking water may be considered the main source of exposure to As, and the biotransference factor for milk ranges from 1.5 × 10(-5) to 4.3 × 10(-4). Therefore, BTF provides a simple tool for the estimation of arsenic levels in milk through the As livestock drinking water content. PMID:27155835

  3. Polarization Factors and Spin-Transfer Torque in Magnetic Tunneling Junctions

    NASA Astrophysics Data System (ADS)

    Slonczewski, John

    2004-03-01

    Recent advances in fabrication of magnetic tunnel junctions having small RA enhance the prospect of 2-terminal memory elements using spin transfer for writing and TMR for reading. Using Bardeen theory, I find a sufficient condition for the existence of the tunnel-effective polarization factors which I-V experiments support. The mere presence of an ideal crystalline slab within the barrier suffices, regardless of electron structure and atomic disorder within the magnets and interface regions. I find the moment-coplanar torque density L_R=(h/4π e)P_LJ_0sin θ acting on a right magnet with applied voltage V. Here, P_L(V) and P_R(V) are the polarization factors of the left and right magnets, and J_0(V) is the mean current density in the conventional expression J=J_0(1+P_LP_Rs θ ). This connection between LR and J may aid laboratory exploration of junction technology for current-driven switching by study of J(V,θ ) prior to the difficult fabrication of pillars having submicron dimensions.

  4. Plasmid Transfer of Plasminogen K1-5 Reduces Subcutaneous Hepatoma Growth by Affecting Inflammatory Factors

    PubMed Central

    Koch, Lea A.; Strassburg, Christian P.; Raskopf, Esther

    2014-01-01

    There is evidence that plasminogen K1-5 (PlgK1-5) directly affects tumour cells and inflammation. Therefore, we analysed if PlgK1-5 has immediate effects on hepatoma cells and inflammatory factors in vitro and in vivo. In vitro, effects of plasmid encoding PlgK1-5 (pK1-5) on Hepa129, Hepa1-6, and HuH7 cell viability, apoptosis, and proliferation as well as VEGF and TNF-alpha expression and STAT3-phosphorylation were investigated. In vivo, tumour growth, proliferation, vessel density, and effects on vascular endothelial growth factor (VEGF) and tumour necrosis factor alpha (TNF-alpha) expression were examined following treatment with pK1-5. In vivo, pK1-5 halved cell viability; cell death was increased by up to 15% compared to the corresponding controls. Proliferation was not affected. VEGF, TNF-alpha, and STAT3-phosphorylation were affected following treatment with pK1-5. In vivo, ten days after treatment initiation, pK1-5 reduced subcutaneous tumour growth by 32% and mitosis by up to 77% compared to the controls. Vessel density was reduced by 50%. TNF-alpha levels in tumour and liver tissue were increased, whereas VEGF levels in tumours and livers were reduced after pK1-5 treatment. Taken together, plasmid gene transfer of PlgK1-5 inhibits hepatoma (cell) growth not only by reducing vessel density but also by inducing apoptosis, inhibiting proliferation, and triggering inflammation. PMID:24895598

  5. Bacterial α2-macroglobulins: colonization factors acquired by horizontal gene transfer from the metazoan genome?

    PubMed Central

    Budd, Aidan; Blandin, Stephanie; Levashina, Elena A; Gibson, Toby J

    2004-01-01

    Background Invasive bacteria are known to have captured and adapted eukaryotic host genes. They also readily acquire colonizing genes from other bacteria by horizontal gene transfer. Closely related species such as Helicobacter pylori and Helicobacter hepaticus, which exploit different host tissues, share almost none of their colonization genes. The protease inhibitor α2-macroglobulin provides a major metazoan defense against invasive bacteria, trapping attacking proteases required by parasites for successful invasion. Results Database searches with metazoan α2-macroglobulin sequences revealed homologous sequences in bacterial proteomes. The bacterial α2-macroglobulin phylogenetic distribution is patchy and violates the vertical descent model. Bacterial α2-macroglobulin genes are found in diverse clades, including purple bacteria (proteobacteria), fusobacteria, spirochetes, bacteroidetes, deinococcids, cyanobacteria, planctomycetes and thermotogae. Most bacterial species with bacterial α2-macroglobulin genes exploit higher eukaryotes (multicellular plants and animals) as hosts. Both pathogenically invasive and saprophytically colonizing species possess bacterial α2-macroglobulins, indicating that bacterial α2-macroglobulin is a colonization rather than a virulence factor. Conclusions Metazoan α2-macroglobulins inhibit proteases of pathogens. The bacterial homologs may function in reverse to block host antimicrobial defenses. α2-macroglobulin was probably acquired one or more times from metazoan hosts and has then spread widely through other colonizing bacterial species by more than 10 independent horizontal gene transfers. yfhM-like bacterial α2-macroglobulin genes are often found tightly linked with pbpC, encoding an atypical peptidoglycan transglycosylase, PBP1C, that does not function in vegetative peptidoglycan synthesis. We suggest that YfhM and PBP1C are coupled together as a periplasmic defense and repair system. Bacterial α2-macroglobulins might

  6. Factors Influencing Lava-Substrate Heat Transfer and Implications for Thermomechanical Erosion

    NASA Technical Reports Server (NTRS)

    Fagents, S. A.; Greeley, R.; Lenat, J. F. (Editor)

    2001-01-01

    We develop numerical simulations of basaltic lava flowing laminarly over a basalt substrate in order to examine the details of the lava dynamics and thermal boundary layers and to understand the implications for substrate heating. As the initial stage of a larger study of thermomechanical erosion in different planetary environments, we aim to understand why erosion occurs on Earth, why erosion features are not ubiquitous given the high temperatures involved, and whether it is a plausible mechanism for the formation of planetary channels such as lunar sinuous rilles and Venusian canali. Here we confine our attention to terrestrial lavas with well-known properties and eruption parameters. With relatively simple computational fluid dynamic simulations, most closely representing tube-fed hawaiian basalts (for which erosion has been documented), we demonstrate the importance of incorporating several key factors in models of lava flow/ substrate heat transfer, which have commonly been neglected in previous treatments. By addressing the interaction of the flow dynamics and heat transfer in the lava, our work suggests that the development of a temperature gradient in the base of the lava, even for undeveloped flow, has a significant influence on substrate temperature. The sensitivity of the lava-substrate interface temperature to the thermophysical properties of the lava and substrate suggests that a delicate balance is required for partial melting to occur. Thus, it might take weeks of continuous flow to initiate partial melting of the substrate at distances of several kilometers from the vent. These durations exceed the periods of stability typical of lava flowing in tubes; pauses, blockages, surges, and break-outs frequently disrupt the flow. However, natural irregularities in the flow dynamics or substrate topography might help to initiate and maintain substrate melting on shorter timescales by disturbing the intimately coupled dynamic and thermal boundary layers

  7. AAV-mediated delivery of the transcription factor XBP1s into the striatum reduces mutant Huntingtin aggregation in a mouse model of Huntington's disease

    SciTech Connect

    Zuleta, Amparo; Vidal, Rene L.; Armentano, Donna; Parsons, Geoffrey; Hetz, Claudio

    2012-04-13

    Highlights: Black-Right-Pointing-Pointer The contribution of ER stress to HD has not been directly addressed. Black-Right-Pointing-Pointer Expression of XBP1s using AAVs decreases Huntingtin aggregation in vivo. Black-Right-Pointing-Pointer We describe a new in vivo model of HD based on the expression of a large fragment of mHtt-RFP. -- Abstract: Huntington's disease (HD) is caused by mutations that expand a polyglutamine region in the amino-terminal domain of Huntingtin (Htt), leading to the accumulation of intracellular inclusions and progressive neurodegeneration. Recent reports indicate the engagement of endoplasmic reticulum (ER) stress responses in human HD post mortem samples and animal models of the disease. Adaptation to ER stress is mediated by the activation of the unfolded protein response (UPR), an integrated signal transduction pathway that attenuates protein folding stress by controlling the expression of distinct transcription factors including X-Box binding protein 1 (XBP1). Here we targeted the expression of XBP1 on a novel viral-based model of HD. We delivered an active form of XBP1 locally into the striatum of adult mice using adeno-associated vectors (AAVs) and co-expressed this factor with a large fragment of mutant Htt as a fusion protein with RFP (Htt588{sup Q95}-mRFP) to directly visualize the accumulation of Htt inclusions in the brain. Using this approach, we observed a significant reduction in the accumulation of Htt588{sup Q95}-mRFP intracellular inclusion when XBP1 was co-expressed in the striatum. These results contrast with recent findings indicating a protective effect of XBP1 deficiency in neurodegeneration using knockout mice, and suggest a potential use of gene therapy strategies to manipulate the UPR in the context of HD.

  8. Plasmid Specificity of The Origin of Transfer of Sex Factor F

    PubMed Central

    Reeves, Peter; Willetts, Neil

    1974-01-01

    The ability of F-like plasmids to promote transfer from the F origin of transfer was determined. Chromosome transfer was measured from plasmid derivatives of RecA− Hfr deletion strains which had lost all the F transfer genes but which in some cases retained, and in others had also lost, the origin sequence. ColV2 and ColVBtrp could initiate transfer from the F origin, but R100-1, R1-19, and R538-1 drd could not. These results can be correlated with the plasmid specificity of the traI components of the different plasmid transfer systems, supporting the hypothesis that the origin of transfer is the site of action of the traI product. Most F-like plasmids, including R1-19 and R538-1 drd, could transfer ColE1, consistent with previous findings that the (plasmid-specific) traI product is not necessary for ColE1 transfer by Flac; ColE1 transfer may be initiated by a ColE1-or host-determined product. R100-1 and R136fin− could not transfer ColE1 efficiently, apparently because of differences residing in their pilus-forming genes. PMID:4608577

  9. Effect of ferrite addition above the base ferrite on the coupling factor of wireless power transfer for vehicle applications

    NASA Astrophysics Data System (ADS)

    Batra, T.; Schaltz, E.; Ahn, S.

    2015-05-01

    Power transfer capability of wireless power transfer systems is highly dependent on the magnetic design of the primary and secondary inductors and is measured quantitatively by the coupling factor. The inductors are designed by placing the coil over a ferrite base to increase the coupling factor and reduce magnetic emissions to the surroundings. Effect of adding extra ferrite above the base ferrite at different physical locations on the self-inductance, mutual inductance, and coupling factor is under investigation in this paper. The addition can increase or decrease the mutual inductance depending on the placement of ferrite. Also, the addition of ferrite increases the self-inductance of the coils, and there is a probability for an overall decrease in the coupling factor. Correct placement of ferrite, on the other hand, can increase the coupling factor relatively higher than the base ferrite as it is closer to the other inductor. Ferrite being a heavy compound of iron increases the inductor weight significantly and needs to be added judiciously. Four zones have been identified in the paper, which shows different sensitivity to addition of ferrite in terms of the two inductances and coupling factor. Simulation and measurement results are presented for different air gaps between the coils and at different gap distances between the ferrite base and added ferrite. This paper is beneficial in improving the coupling factor while adding minimum weight to wireless power transfer system.

  10. Kinetic model for erythrocyte aggregation.

    PubMed

    Bertoluzzo, S M; Bollini, A; Rasia, M; Raynal, A

    1999-01-01

    It is well known that light transmission through blood is the most widely utilized method for the study of erythrocyte aggregation. The curves obtained had been considered empirically as exponential functions. In consequence, the process becomes characterized by an only parameter that varies with all the process factors without discrimination. In the present paper a mathematical model for RBC aggregation process is deduced in accordance with von Smoluchowski's theory about the kinetics of colloidal particles agglomeration. The equation fitted the experimental pattern of the RBC suspension optical transmittance closely and contained two parameters that estimate the most important characteristics of the aggregation process separately, i.e., (1) average size of rouleaux at equilibrium and (2) aggregation rate. The evaluation of the method was assessed by some factors affecting erythrocyte aggregation, such as temperature, plasma dilutions, Dextran 500, Dextran 70 and PVP 360, at different media concentrations, cellular membrane alteration by the alkylating agent TCEA, and decrease of medium osmolarity. Results were interpreted considering the process characteristics estimated by the parameters, and there were also compared with similar studies carried out by other authors with other methods. This analysis allowed us to conclude that the equation proposed is reliable and useful to study erythrocyte aggregation. PMID:10660481

  11. AggLb Is the Largest Cell-Aggregation Factor from Lactobacillus paracasei Subsp. paracasei BGNJ1-64, Functions in Collagen Adhesion, and Pathogen Exclusion In Vitro

    PubMed Central

    Miljkovic, Marija; Strahinic, Ivana; Tolinacki, Maja; Zivkovic, Milica; Kojic, Snezana; Golic, Natasa; Kojic, Milan

    2015-01-01

    Eleven Lactobacillus strains with strong aggregation abilities were selected from a laboratory collection. In two of the strains, genes associated with aggregation capability were plasmid located and found to strongly correlate with collagen binding. The gene encoding the auto-aggregation-promoting protein (AggLb) of Lactobacillus paracasei subsp. paracasei BGNJ1-64 was cloned using a novel, wide-range-host shuttle cloning vector, pAZILSJ. The clone pALb35, containing a 11377-bp DNA fragment, was selected from the SacI plasmid library for its ability to provide carriers with the aggregation phenotype. The complete fragment was sequenced and four potential ORFs were detected, including the aggLb gene and three surrounding transposase genes. AggLb is the largest known cell-surface protein in lactobacilli, consisting of 2998 aa (318,611 Da). AggLb belongs to the collagen-binding superfamily and its C-terminal region contains 20 successive repeats that are identical even at the nucleotide level. Deletion of aggLb causes a loss of the capacity to form cell aggregates, whereas overexpression increases cellular aggregation, hydrophobicity and collagen-binding potential. PCR screening performed with three sets of primers based on the aggLb gene of BGNJ1-64 enabled detection of the same type of aggLb gene in five of eleven selected aggregation-positive Lactobacillus strains. Heterologous expression of aggLb confirmed the crucial role of the AggLb protein in cell aggregation and specific collagen binding, indicating that AggLb has a useful probiotic function in effective colonization of host tissue and prevention of pathogen colonization. PMID:25955159

  12. Visualization of two transfer RNAs trapped in transit during elongation factor G-mediated translocation

    PubMed Central

    Ramrath, David J. F.; Lancaster, Laura; Sprink, Thiemo; Mielke, Thorsten; Loerke, Justus; Noller, Harry F.; Spahn, Christian M. T.

    2013-01-01

    During protein synthesis, coupled translocation of messenger RNAs (mRNA) and transfer RNAs (tRNA) through the ribosome takes place following formation of each peptide bond. The reaction is facilitated by large-scale conformational changes within the ribosomal complex and catalyzed by elongtion factor G (EF-G). Previous structural analysis of the interaction of EF-G with the ribosome used either model complexes containing no tRNA or only a single tRNA, or complexes where EF-G was directly bound to ribosomes in the posttranslocational state. Here, we present a multiparticle cryo-EM reconstruction of a translocation intermediate containing two tRNAs trapped in transit, bound in chimeric intrasubunit ap/P and pe/E hybrid states. The downstream ap/P-tRNA is contacted by domain IV of EF-G and P-site elements within the 30S subunit body, whereas the upstream pe/E-tRNA maintains tight interactions with P-site elements of the swiveled 30S head. Remarkably, a tight compaction of the tRNA pair can be seen in this state. The translocational intermediate presented here represents a previously missing link in understanding the mechanism of translocation, revealing that the ribosome uses two distinct molecular ratchets, involving both intra- and intersubunit rotational movements, to drive the synchronous movement of tRNAs and mRNA. PMID:24324168

  13. Transfer factor, lung volumes, resistance and ventilation distribution in healthy adults.

    PubMed

    Verbanck, Sylvia; Van Muylem, Alain; Schuermans, Daniel; Bautmans, Ivan; Thompson, Bruce; Vincken, Walter

    2016-01-01

    Monitoring of chronic lung disease requires reference values of lung function indices, including putative markers of small airway function, spanning a wide age range.We measured spirometry, transfer factor of the lung for carbon monoxide (TLCO), static lung volume, resistance and ventilation distribution in a healthy population, studying at least 20 subjects per sex and per decade between the ages of 20 and 80 years.With respect to the Global Lung Function Initiative reference data, our subjects had average z-scores for forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC of -0.12, 0.04 and -0.32, respectively. Reference equations were obtained which could account for a potential dependence of index variability on age and height. This was done for (but not limited to) indices that are pertinent to asthma and chronic obstructive pulmonary disease studies: forced expired volume in 6 s, forced expiratory flow, TLCO, specific airway conductance, residual volume (RV)/total lung capacity (TLC), and ventilation heterogeneity in acinar and conductive lung zones.Deterioration in acinar ventilation heterogeneity and lung clearance index with age were more marked beyond 60 years, and conductive ventilation heterogeneity showed the greatest increase in variability with age. The most clinically relevant deviation from published reference values concerned RV/TLC values, which were considerably smaller than American Thoracic Society/European Respiratory Society-endorsed reference values. PMID:26585426

  14. Intercellular transfer of tissue factor via the uptake of tumor-derived microvesicles.

    PubMed

    Lima, Luize G; Leal, Ana Carolina; Vargas, Gabriele; Porto-Carreiro, Isabel; Monteiro, Robson Q

    2013-10-01

    Coagulation proteins play a critical role in numerous aspects of tumor biology. Cancer cells express tissue factor (TF), the protein that initiates blood clotting, which frequently correlates with processes related to cell aggressiveness, including primary tumor growth, invasion, and metastasis. It has been demonstrated that TF gets incorporated into tumor-derived microvesicles (MVs), a process that has been correlated with cancer-associated thrombosis. Here, we describe the exchange of TF-bearing MVs between breast cancer cell lines with different aggressiveness potential. The highly invasive and metastatic MDA-MB-231 cells displayed higher surface levels of functional TF compared with the less aggressive MCF-7 cells. MVs derived from MDA-MB-231 cells were enriched in TF and accelerated plasma coagulation, but MCF-7 cell-derived MVs expressed very low levels of TF. Incubating MCF-7 cells with MDA-MB-231 MVs significantly increased the TF activity. This phenomenon was not observed upon pretreatment of MVs with anti-TF or annexin-V, which blocks phosphatidylserine sites on the surface of MVs. Our data indicated that TF-bearing MVs can be transferred between different populations of cancer cells and may therefore contribute to the propagation of a TF-related aggressive phenotype among heterogeneous subsets of cells in a tumor. PMID:23993901

  15. Gene Transfer of Brain-derived Neurotrophic Factor (BDNF) Prevents Neurodegeneration Triggered by FXN Deficiency.

    PubMed

    Katsu-Jiménez, Yurika; Loría, Frida; Corona, Juan Carlos; Díaz-Nido, Javier

    2016-05-01

    Friedreich's ataxia is a predominantly neurodegenerative disease caused by recessive mutations that produce a deficiency of frataxin (FXN). Here, we have used a herpesviral amplicon vector carrying a gene encoding for brain-derived neurotrophic factor (BDNF) to drive its overexpression in neuronal cells and test for its effect on FXN-deficient neurons both in culture and in the mouse cerebellum in vivo. Gene transfer of BDNF to primary cultures of mouse neurons prevents the apoptosis which is triggered by the knockdown of FXN gene expression. This neuroprotective effect of BDNF is also observed in vivo in a viral vector-based knockdown mouse cerebellar model. The injection of a lentiviral vector carrying a minigene encoding for a FXN-specific short hairpin ribonucleic acid (shRNA) into the mouse cerebellar cortex triggers a FXN deficit which is accompanied by significant apoptosis of granule neurons as well as loss of calbindin in Purkinje cells. These pathological changes are accompanied by a loss of motor coordination of mice as assayed by the rota-rod test. Coinjection of a herpesviral vector encoding for BDNF efficiently prevents both the development of cerebellar neuropathology and the ataxic phenotype. These data demonstrate the potential therapeutic usefulness of neurotrophins like BDNF to protect FXN-deficient neurons from degeneration. PMID:26849417

  16. Free functional muscle transfer failure and thrombophilic gene mutations as a potential risk factor: a case report.

    PubMed

    Vekris, Marios D; Ovrenovits, Maria; Dova, Lefkothea; Beris, Alexandros E; Soucacos, Panayiotis N; Kolaitis, Nikolaos; Vartholomatos, George

    2007-01-01

    The evolution of microsurgery popularized the free functioning muscle transfers as secondary procedures to reanimate paralyzed extremities after severance of the brachial plexus, especially when the surgeon deals with late cases. Studies considering transplantation, describe thrombophilic factors as a cause of severe complications after transplantation, such as acute or early rejection episodes, delayed graft function, or chronic graft dysfunction. It is the first time that thrombophilia associated with free muscle-graft rejection is reported. A young man who had two free functional muscle transfers for brachial plexus reconstruction in the same forearm within an interval of 6 months. The free functional muscle transfer was failed in both cases because of vein thrombosis and subsequent arterial clot. The possibility of thrombophilia was investigated and during the genetic investigation it was discovered that he was heterozygous for the mutations of factor V, G1691A-Leiden, A4070G and homozygous for the MTHFR C677T mutation. PMID:17295258

  17. Perceptions of a Learning Organization and Factors within the Work Environment That Influence Transfer of Training in Law Enforcement

    ERIC Educational Resources Information Center

    Hunter-Johnson, Yvonne

    2012-01-01

    The purpose of this study was to determine law enforcement officers' perception of factors within the workplace that influence transfer of training and their perception of the organization being a learning organization. The study actually had three parts. First, it intended to investigate the perception of law enforcement officers regarding…

  18. Learning What Matters: Exploring the Factors Affecting Learning Transfers in Child Welfare Competencies and Career Interest in Child Welfare

    ERIC Educational Resources Information Center

    Liao, Aries Meng-Wei

    2012-01-01

    The understanding of the factors impacting MSW students' interests and motivation to learn child welfare competencies, and how they affect learning transfer of the subject is important for the development of a knowledgeable, competent, and committed workforce that serves children and families in the United States. Practitioners need to attain…

  19. Transfer factors and effective half-lives of (134)Cs and (137)Cs in different environmental sample types obtained from Northern Finland: case Fukushima accident.

    PubMed

    Koivurova, Matias; Leppänen, Ari-Pekka; Kallio, Antti

    2015-08-01

    The Fukushima NPP accident caused a small but detectable cesium fallout in northern Finland, of the order of 1 Bq/m(2). This fallout transferred further to soil, water, flora and fauna. By using modern HPGe detector systems traces of (134)Cs from the Fukushima fallout were observed in various samples of biota. In northern Finland different types of environmental samples such as reindeer meat, berries, fish, lichens and wolf were collected during 2011-2013. The observed (134)Cs concentrations varied from 0.1 Bq/kg to a few Bq/kg. By using the known (134)Cs/(137)Cs ratio observed in Fukushima fallout the increase of the Fukushima accident to the (137)Cs concentrations was found to vary from 0.06 % to 6.9 % depending on the sample type. The aggregated transfer factors (Tag) and effective half-lives (Teff) for (134)Cs and (137)Cs were also determined and then compared with known values found from earlier studies which are calculated based on the fallout from the Chernobyl accident. Generally, the Tag and Teff values determined in this study were found to agree with the values found in the earlier studies. The Teff values were sample-type specific and were found to vary from 0.91 to 2.1 years for (134)Cs and the estimates for (137)Cs ranged between 1.6 and 19 years. Interestingly, the ground lichens had the longest Teff whereas the beard lichen had the shortest. In fauna, highest Tag values were determined for wolf meat ranging between 1.0 and 2.2 m(2)/kg. In flora, the highest Tag values were determined for beard lichens, ranging from 1.9 m(2)/kg to 3.5 m(2)/kg. PMID:25935505

  20. Aqueous Al2O3 nanofluids: the important factors impacting convective heat transfer

    NASA Astrophysics Data System (ADS)

    Cao, Jianguo; Ding, Yulong; Ma, Caiyun

    2014-12-01

    A high accuracy, counter flow double pipe heat exchanger system is designed for the measurement of convective heat transfer coefficients with different nanofluids. Both positive and negative enhancement of convective heat transfer of alumina nanofluids are found in the experiments. A modified equation was proposed to explain above phenomena through the physic properties of nanofluids such as thermal conductivity, special heat capacity and viscosity.

  1. External and Institutional Factors Affecting Community College Student-Transfer Activity.

    ERIC Educational Resources Information Center

    Banks, Debra L.

    A study was conducted to identify the environmental conditions and relationships between external and institutional conditions that have a significant effect upon student transfer activity. A sample of 78 colleges in 15 states were selected from institutions participating in a national transfer project; 42% were located in Texas or California. The…

  2. Predisposition Factors of Career and Technical Education Transfer Students: A Hermeneutic Phenomenology Study

    ERIC Educational Resources Information Center

    Hioki, Warren; Lester, Derek; Martinez, Mario

    2015-01-01

    Six college students, who were career and technical education (CTE) transfer students in the state of Nevada, were interviewed Spring Semester of 2009. The study used a hermeneutic phenomenology framework as the method to identify those predisposition variables that heavily influenced the students in their decision to transfer to a senior…

  3. Assessing Dynamic Spectral Causality by Lagged Adaptive Directed Transfer Function and Instantaneous Effect Factor

    PubMed Central

    Xu, Haojie; Lu, Yunfeng; Zhu, Shanan

    2014-01-01

    It is of significance to assess the dynamic spectral causality among physiological signals. Several practical estimators adapted from spectral Granger causality have been exploited to track dynamic causality based on the framework of time-varying multivariate autoregressive (tvMVAR) models. The non-zero covariance of the model’s residuals has been used to describe the instantaneous effect phenomenon in some causality estimators. However, for the situations with Gaussian residuals in some autoregressive models, it is challenging to distinguish the directed instantaneous causality if the sufficient prior information about the “causal ordering” is missing. Here, we propose a new algorithm to assess the time-varying causal ordering of tvMVAR model under the assumption that the signals follow the same acyclic causal ordering for all time lags and to estimate the instantaneous effect factor (IEF) value in order to track the dynamic directed instantaneous connectivity. The time-lagged adaptive directed transfer function (ADTF) is also estimated to assess the lagged causality after removing the instantaneous effect. In the present study, we firstly investigated the performance of the causal-ordering estimation algorithm and the accuracy of IEF value. Then, we presented the results of IEF and time-lagged ADTF method by comparing with the conventional ADTF method through simulations of various propagation models. Statistical analysis results suggest that the new algorithm could accurately estimate the causal ordering and give a good estimation of the IEF values in the Gaussian residual conditions. Meanwhile, the time-lagged ADTF approach is also more accurate in estimating the time-lagged dynamic interactions in a complex nervous system after extracting the instantaneous effect. In addition to the simulation studies, we applied the proposed method to estimate the dynamic spectral causality on real visual evoked potential (VEP) data in a human subject. Its usefulness in

  4. Modifiers of mutant huntingtin aggregation

    PubMed Central

    Teuling, Eva; Bourgonje, Annika; Veenje, Sven; Thijssen, Karen; de Boer, Jelle; van der Velde, Joeri; Swertz, Morris; Nollen, Ellen

    2011-01-01

    Protein aggregation is a common hallmark of a number of age-related neurodegenerative diseases, including Alzheimer’s, Parkinson’s, and polyglutamine-expansion disorders such as Huntington’s disease, but how aggregation-prone proteins lead to pathology is not known. Using a genome-wide RNAi screen in a C. elegans-model for polyglutamine aggregation, we previously identified 186 genes that suppress aggregation. Using an RNAi screen for human orthologs of these genes, we here present 26 human genes that suppress aggregation of mutant huntingtin in a human cell line. Among these are genes that have not been previously linked to mutant huntingtin aggregation. They include those encoding eukaryotic translation initiation, elongation and translation factors, and genes that have been previously associated with other neurodegenerative diseases, like the ATP-ase family gene 3-like 2 (AFG3L2) and ubiquitin-like modifier activating enzyme 1 (UBA1). Unravelling the role of these genes will broaden our understanding of the pathogenesis of Huntington’s disease. PMID:21915392

  5. "A Hand Hold for a Little Bit": Factors Facilitating the Success of Community College Transfer Students to a Large Research University

    ERIC Educational Resources Information Center

    Townsend, Barbara K.; Wilson, Kristin

    2006-01-01

    To understand factors affecting the academic and social integration of community college transfer students, we interviewed 19 students who transferred to one state's large Research-Extensive university. We inquired about the transfer process, efforts of the university to orient and assist them, and perceptions of the university versus the…

  6. Picomolar platelet-activating factor mobilizes Ca to change platelet shape without activating phospholipase C or protein kinase C; simultaneous fluorometric measurement of intracellular free Ca concentration and aggregation.

    PubMed

    James-Kracke, M R; Sexe, R B; Shukla, S D

    1994-11-01

    The purpose of this study was to investigate signal transduction mechanisms activated by low and high concentrations of platelet-activating factor (PAF) in rabbit platelets and to contrast the responses to those induced by thrombin. We measured changes in intracellular free calcium ([Ca++]i) with fura2, while monitoring light scatter simultaneously as a measure of shape change and aggregation in a dual-excitation dual-emission spectrofluorometer. An abrupt 20% fall in light scatter, coincident with the peak of the [Ca++]i, indicated shape change in Ca-containing or Ca-free medium and was blocked by BAPTA loading and 10 microM cytochalasin B. A secondary decline in light scatter, indicating aggregation, occurred only in Ca-containing medium and only under conditions favoring protein kinase C (PKC) activation. PAF at 10(-12) M did not increase 1,4,5-inositol triphosphate content, which suggested PKC would not be activated. However, PAF at 10(-12) rapidly increased [Ca++]i to 900 nM in 7 sec seemingly by Ca influx through receptor-operated channels inducing shape change. PAF at 10(-9) and 10(-8) M increased [Ca++]i to 2 microM in 12 sec and induced both shape change and aggregation. However, in platelets pretreated with 100 nM staurosporine to inhibit protein kinases, 10(-9) M PAF did not cause aggregation even though [Ca++]i still rose to 2 microM, which indicated that PKC plays a role in aggregation but not in Ca++ mobilization.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7965802

  7. Investigating the mechanisms leading to protein aggregation

    NASA Astrophysics Data System (ADS)

    McNamara, Ruth; McManus, Jennifer J.

    2014-03-01

    The formation of protein aggregates is a feature of several diseases and is a problem during the manufacture of biopharmaceutical and protein based food products. During processing, stability may become compromised leading to the condensation of proteins to form non-native aggregates. The aim of this work is to induce aggregation on model proteins by the imposition of a particular stress to evaluate the extent of aggregation and to assess the degree of structural change to the protein. Aggregation of two proteins, lysozyme and bovine serum albumin has been induced by several mechanisms. Using various techniques (electrophoresis, HPLC, spectroscopic analysis, and microscopic techniques) both the level of aggregation extent of protein unfolding has been investigated for a range of solution conditions. Our results show that the amount of aggregation depends strongly on the mechanism by which non-native aggregation proceeds, and within each mechanism, solution conditions are an important factor. With the exception of aggregation by self-association (which is concentration dependent), the appearance of aggregation is driven by structural changes induced by the applied stress (heat, chemical denaturant, oxidation or contact with a surface). Author would like to acknowledge support from Science Foundation Ireland (SFI), National University of Maynooth John and Pat Hume Scholarship.

  8. Bouncing behavior of microscopic dust aggregates

    NASA Astrophysics Data System (ADS)

    Seizinger, A.; Kley, W.

    2013-03-01

    Context. Bouncing collisions of dust aggregates within the protoplanetary disk may have a significant impact on the growth process of planetesimals. Yet, the conditions that result in bouncing are not very well understood. Existing simulations studying the bouncing behavior used aggregates with an artificial, very regular internal structure. Aims: Here, we study the bouncing behavior of sub-mm dust aggregates that are constructed applying different sample preparation methods. We analyze how the internal structure of the aggregate alters the collisional outcome and we determine the influence of aggregate size, porosity, collision velocity, and impact parameter. Methods: We use molecular dynamics simulations where the individual aggregates are treated as spheres that are made up of several hundred thousand individual monomers. The simulations are run on graphic cards (GPUs). Results: Statistical bulk properties and thus bouncing behavior of sub-mm dust aggregates depend heavily on the preparation method. In particular, there is no unique relation between the average volume filling factor and the coordination number of the aggregate. Realistic aggregates bounce only if their volume filling factor exceeds 0.5 and collision velocities are below 0.1 ms-1. Conclusions: For dust particles in the protoplanetary nebula we suggest that the bouncing barrier may not be such a strong handicap in the growth phase of dust agglomerates, at least in the size range of ≈100 μm.

  9. The Proton Elastic Form Factor Ratio mu(p) G**p(E)/G**p(M) at Low Momentum Transfer

    SciTech Connect

    G. Ron; J. Glister; B. Lee; K. Allada; W. Armstrong; J. Arrington; A. Beck; F. Benmokhtar; B.L. Berman; W. Boeglin; E. Brash; A. Camsonne; J. Calarco; J. P. Chen; Seonho Choi; E. Chudakov; L. Coman; B. Craver; F. Cusanno; J. Dumas; C. Dutta; R. Feuerbach; A. Freyberger; S. Frullani; F. Garibaldi; R. Gilman; O. Hansen; D. W. Higinbotham; T. Holmstrom; C.E. Hyde; H. Ibrahim; Y. Ilieva; C. W. de Jager; X. Jiang; M. K. Jones; A. Kelleher; E. Khrosinkova; E. Kuchina; G. Kumbartzki; J. J. LeRose; R. Lindgren; P. Markowitz; S. May-Tal Beck; E. McCullough; D. Meekins; M. Meziane; Z.-E. Meziani; R. Michaels; B. Moffit; B.E. Norum; Y. Oh; M. Olson; M. Paolone; K. Paschke; C. F. Perdrisat; E. Piasetzky; M. Potokar; R. Pomatsalyuk; I. Pomerantz; A. Puckett; V. Punjabi; X. Qian; Y. Qiang; R. Ransome; M. Reyhan; J. Roche; Y. Rousseau; A. Saha; A.J. Sarty; B. Sawatzky; E. Schulte; M. Shabestari; A. Shahinyan; R. Shneor; S. ˇ Sirca; K. Slifer; P. Solvignon; J. Song; R. Sparks; R. Subedi; S. Strauch; G. M. Urciuoli; K. Wang; B. Wojtsekhowski; X. Yan; H. Yao; X. Zhan; X. Zhu

    2007-11-01

    High precision measurements of the proton elastic form factor ratio have been made at four-momentum transfers, Q^2, between 0.2 and 0.5 GeV^2. The new data, while consistent with previous results, clearly show a ratio less than unity and significant differences from the central values of several recent phenomenological fits. By combining the new form-factor ratio data with an existing cross-section measurement, one finds that in this Q^2 range the deviation from unity is primarily due to GEp being smaller than the dipole parameterization.

  10. Platelet aggregation test

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003669.htm Platelet aggregation test To use the sharing features on this page, please enable JavaScript. The platelet aggregation blood test checks how well platelets , a ...

  11. Thermodynamics of Protein Aggregation

    NASA Astrophysics Data System (ADS)

    Osborne, Kenneth L.; Barz, Bogdan; Bachmann, Michael; Strodel, Birgit

    Amyloid protein aggregation characterizes many neurodegenerative disorders, including Alzheimer's, Parkinson's, and Creutz- feldt-Jakob disease. Evidence suggests that amyloid aggregates may share similar aggregation pathways, implying simulation of full-length amyloid proteins is not necessary for understanding amyloid formation. In this study we simulate GNNQQNY, the N-terminal prion-determining domain of the yeast protein Sup35 to investigate the thermodynamics of structural transitions during aggregation. We use a coarse-grained model with replica-exchange molecular dynamics to investigate the association of 3-, 6-, and 12-chain GNNQQNY systems and we determine the aggregation pathway by studying aggregation states of GN- NQQNY. We find that the aggregation of the hydrophilic GNNQQNY sequence is mainly driven by H-bond formation, leading to the formation of /3-sheets from the very beginning of the assembly process. Condensation (aggregation) and ordering take place simultaneously, which is underpinned by the occurrence of a single heat capacity peak only.

  12. Platelet aggregation test

    MedlinePlus

    The platelet aggregation blood test checks how well platelets , a part of blood, clump together and cause blood to clot. ... Decreased platelet aggregation may be due to: Autoimmune ... Fibrin degradation products Inherited platelet function defects ...

  13. Influence of chemical and biological factors on trophic transfer of persistent organic pollutants in the northwater polynya marine food web.

    PubMed

    Fisk, A T; Hobson, K A; Norstrom, R J

    2001-02-15

    Persistent organic pollutants (POPs) and stable isotopes of nitrogen (delta 15N) were measured in zooplankton (6 species), a benthic invertebrate (Anonyx nugax), Arctic cod (Boreogadus saida), seabirds (6 species), and ringed seals (Phoca hispida) collected in 1998 in the Northwater Polynya to examine effects of biological and chemical factors on trophic transfer of POPs in an Arctic marine food web. Strong positive relationships were found between recalcitrant POP concentrations (lipid corrected) and trophic level based on stable isotopes of nitrogen, providing clear evidence of POP biomagnification in Arctic marine food webs. Food web magnification factors (FWMFs), derived from the slope of the POP--trophic level relationship, provided an overall magnification factor for the food web but over and underestimated biomagnification factors (BMFs) based on predator--prey concentrations in poikilotherms (fish) and homeotherms (seabirds and mammals), respectively. Greater biomagnification in homeotherms was attributed to their greater energy requirement and subsequent feeding rates. Within the homeotherms, seabirds had greater BMFs than ringed seals, consistent with greater energy demands in birds. Scavenging from marine mammal carcasses and accumulation in more contaminated winter habitats were considered important variables in seabird BMFs. Metabolic differences between species resulted in lower than expected BMFs, which would not be recognized in whole food web trophic level--POP relationships. The use of sigma POP groups, such as sigma PCB, is problematic because FWMFs and BMFs varied considerably between individual POPs. FWMFs of recalcitrant POPs had a strong positive relationship with log octanol--water partition coefficient (Kow). Results of this study show the utility of using delta 15N to characterize trophic level and trophic transfer of POPs but highlight the effects of species and chemical differences on trophic transfer of POPs that can be overlooked when

  14. Transfer Rates of Texas Hispanic Community College Students to 4-Year Institutions: Selected Institutional Factors

    ERIC Educational Resources Information Center

    Klement, Emily Conrady

    2012-01-01

    The purpose of this non-experimental, quantitative study was to determine how well selected institutional characteristics explain the variance in Hispanic community college students' transfer rates to 4-year institutions. Due to the rapidly growing Texas Hispanic population, understanding challenges to their educational attainment has become…

  15. EXPERIMENTAL METHODOLOGIES AND PRELIMINARY TRANSFER FACTOR DATA FOR ESTIMATION OF DERMAL EXPOSURES TO PARTICLES

    EPA Science Inventory

    Developmental efforts and experimental data are described that focused on quantifying the transfer of particles on a mass basis from indoor surfaces to human skin. Methods were developed that utilized a common fluorescein-tagged Arizona Test Dust (ATD) as a possible surrogate ...

  16. Factors Affecting Persistence of Undergraduate Students in a Fisheries and Wildlife Program: Transfer Students

    ERIC Educational Resources Information Center

    Wolter, Bjorn H. K.; Millenbah, Kelly F.; Montgomery, Robert A.; Schneider, James W.

    2011-01-01

    Transfer students are of recognized importance to postsecondary education and every year feed thousands of students into natural resources programs across America. This influx of students can have a sustaining effect on many academic programs, including fisheries and wildlife programs, which are suffering from a nation-wide decrease in interest…

  17. Learning Factors Transfer Analysis: Using Learning Curve Analysis to Automatically Generate Domain Models

    ERIC Educational Resources Information Center

    Pavlik, Philip I. Jr.; Cen, Hao; Koedinger, Kenneth R.

    2009-01-01

    This paper describes a novel method to create a quantitative model of an educational content domain of related practice item-types using learning curves. By using a pairwise test to search for the relationships between learning curves for these item-types, we show how the test results in a set of pairwise transfer relationships that can be…

  18. Role of paf-acether in the mediation of pathophysiological responses to aggregated immunoglobulins. Studies with the platelet-activating factor receptor antagonist BN 52021.

    PubMed

    Fernandez-Gallardo, S; Cano, E; Braquet, P; Sanchez Crespo, M

    1988-01-01

    Sprague-Dawley rats were challenged with an intravenous (i.v.) infusion of soluble aggregates of immunoglobulin G. Animals receiving a dose of aggregates of 40 mg/kg showed a significantly reduced time of lysis of diluted blood clot, which paralleled the appearance in plasma of tissue-type plasminogen activator. These changes occurred about 5-10 min after the challenge, which is a more protracted time-course than that observed in response to paf-acether. A significant increase in serum levels of N-acetylglucosaminidase was also observed in the animals several minutes after challenge. Blood neutrophil count showed a 50% reduction that reached its maximum at 10 min and was followed by an overshoot after 30 min. In experiments in rats previously depleted of circulating PMN by treatment with vinblastine, no significant differences were observed in N-acetylglucosaminidase release as compared to non-treated animals. Since prior evidence indicated that endogenously generated paf-acether could be a mediator responsible for these changes, at least to some extent, the compound BN 52021, a specific antagonist of the paf-acether receptor was given to these animals prior to the challenge with the complexes. All the above mentioned responses were significantly reduced by BN 52021, which is in keeping with the hypothesis involving endogenous paf-acether release in the mediation of these changes. By contrast, BN 52021 did not interfere with the clearance of the aggregates from the circulation, which seems to be a beneficial mechanism to reduce immune-mediated tissue injury. These data extend the number of paf-acether mediated pathophysiological changes that can be observed in response to immune aggregates. PMID:3139574

  19. Evaluating recipient and embryo factors that affect pregnancy rates of embryo transfer in beef cattle.

    PubMed

    Spell, A R; Beal, W E; Corah, L R; Lamb, G C

    2001-07-15

    The objectives of this experiment were to determine the effects of corpus luteum characteristics, progesterone concentration, donor-recipient synchrony, embryo quality, type, and developmental stage on pregnancy rates after embryo transfer. We synchronized 763 potential recipients for estrus using one of two synchronization protocols: two doses of PGF2alpha (25 mg i.m.) given 11 d apart (Location 1); and, a single norgestomet implant for 7 d with one dose of PGF2alpha (25 mg i.m.) 24 h before implant removal (Location 2). At embryo transfer, ovaries were examined by rectal palpation and ultrasonography. Of the 526 recipients presented for embryo transfer, 122 received a fresh embryo and 326 received a frozen embryo. Pregnancy rates were greater (P < 0.05) with fresh embryos (83%) than frozen-thawed embryos (69%). Pregnancy rates were not affected by embryo grade, embryo stage, donor-recipient synchrony, or the palpated integrity of the CL. Corpus luteum diameter and luteal tissue volume increased as days post-estrus for the recipients increased. However, pregnancy rates did not differ among recipients receiving embryos 6.5 to 8.5 days after estrus (P > 0.1). There was a significant, positive simple correlation between CL diameter or luteal tissue volume and plasma progesterone concentration (r = 0.15, P < 0.01 and r = 0.18, P < 0.01, respectively). There were no significant differences in mean CL diameter, luteal volume or plasma progesterone concentration among recipients that did or did not become pregnant after embryo transfer. We conclude that suitability of a potential embryo transfer recipient is determined by observed estrus and a palpable corpus luteum, regardless of size or quality. PMID:11480620

  20. Characteristics of heavy metal transfer and their influencing factors in different soil-crop systems of the industrialization region, China.

    PubMed

    Chen, Hongyan; Yuan, Xuyin; Li, Tianyuan; Hu, Sun; Ji, Junfeng; Wang, Cheng

    2016-04-01

    Soil heavy metals and their bioaccumulation in agricultural products have attracted widespread concerns, yet the transfer and accumulation characteristics of heavy metals in different soil-crop systems was rarely investigated. Soil and crop samples were collected from the typical agricultural areas in the Yangtze River Delta region, China. The concentrations of Cu, Pb, Zn, Cd and Hg in the soils, roots and grains of rice (Oryza Sativa L.), wheat (Triticum L.) and canola (Brassica napus L.) were determined in this study. Transfer ability of heavy metals in soil-rice system was stronger than those in soil-wheat and soil-canola systems. The wheat showed a strong capacity to transfer Zn, Cu and Cd from root to the grain while canola presented a restricting effect to the intake of Cu and Cd. Soil pH and total organic matter were major factors influencing metal transfer from soil to rice, whereas soil Al2O3 contents presented a negative effect on heavy metal mobility in wheat and canola cultivation systems. The concentration of Zn and Cd in crop grains could well predicted according to the stepwise multiple linear regression models, which could help to quantitatively evaluate the ecologic risk of heavy metal accumulation in crops in the study area. PMID:26771531

  1. CFD analysis of heat transfer and friction factor charaterstics in a circular tube fitted with horizontal baffles twisted tape inserts

    NASA Astrophysics Data System (ADS)

    Salman, Sami D.; Kadhum, Abdul Amir H.; Takriff, Mohd S.; Bakar Mohamad, Abu

    2013-12-01

    Swirl/vortex flow generator is an important form of passive augmentation techniques. Twisted-tape is one of the most important members of this form which is used extensively in different type heat exchangers. This paper reports the effect of twisted tape inserts on heat transfer and friction factor characteristics in circular tube under constant heat flux and laminar flow conditions using CFD simulation. Plain twisted tape inserts with twist ratios (y = 2.93, 3.91) and baffled twisted tape inserts with twist ratio (y = 2.93) have been used for the simulation using Fluent version 6.3.26. The results obtained by simulation matched with the literature correlations for plain tube with the discrepancy of less than ± 8% for Nusselt number and ± 6.25% for friction factor. The results have also revealed that the heat transfer in term of the Nusselt number enhanced with increases of Reynolds number, decreases of twist ratio and baffle insert. Among the various twist ratios, the twisted tape with twist ratio of y=2.93 and baffle is offered a maximum heat transfer enhancement.

  2. Transfer factor of 131I from the fallout to human thyroid dose equivalent after the Chernobyl accident.

    PubMed

    Beno, M; Mikulecký, M; Hrabina, J

    1992-01-01

    A similar pattern of variation with time in observed maxima of daily dose equivalent rates in human thyroids (TD - microSv.d-1) and of daily fallout radioactivities (FR - kBq.m-2) has been found after the Chernobyl accident. An estimate of the time-lag between the maxima in TD lines and the preceding FR peaks was made of about seven days for adult and nine days for juveniles. Applying this time-lag it was possible to estimate transfer factors from the fallout to thyroid dose equivalent: the highest estimated values were 221 microSv/kBq.m-2 for adult and 641 microSv/kBq.m-2 for juvenile thyroids. These values differ from those published by UNSCEAR (United Nations 1988), which have been calculated for various regions of Czechoslovakia, from ingestion and inhalation intake estimates. A broad variation of transfer factor values could be expected to result from such transfer calculations using ingestion and inhalation estimates. The findings also support the concept of a need for prolonged iodine prophylaxy after emissions of radioiodine into the environment. PMID:1609058

  3. Modulation Transfer Function Measurement of Infrared Focal-Plane Arrays with Small Fill Factors

    NASA Astrophysics Data System (ADS)

    de la Barrière, Florence; Druart, Guillaume; Guérineau, Nicolas; Rommeluère, Sylvain; Mugnier, Laurent; Gravrand, Olivier; Baier, Nicolas; Lhermet, Nicolas; Destefanis, Gérard; Derelle, Sophie

    2012-10-01

    This paper describes an original method to measure the modulation transfer function (MTF) of an infrared focal-plane array (IRFPA), based on a diffraction grating called a continuously self-imaging grating (CSIG). We give a general methodology to design the test bench, and we describe the data processing approach which has been developed to extract relevant information about the size of the photodiodes and filtering effects. The MTF measurement capability of this method is illustrated with a cooled IRFPA.

  4. Identification and quantification of factors affecting neonatal immunological transfer in dairy calves in the UK.

    PubMed

    MacFarlane, J A; Grove-White, D H; Royal, M D; Smith, R F

    2015-06-13

    The object of the study was to quantify the prevalence of failure of passive transfer in UK dairy farms and to identify variables that had a significant impact on the rate of immunological transfer. In a six-month study of 444 calvings from seven UK dairy farms, 26 per cent of calves failed to receive adequate immunoglobulin transfer as judged by a plasma total protein (pTP) concentration less than 5.6 g/dl. Colostrum immunoglobulin concentration, indirectly measured using Brix refractometry, showed wide variations with samples ranging from 10.3 to 34.7 Brix units. Thirty-seven per cent of samples were below the suggested cut-off Brix score for colostrum quality of 22 per cent. Potential associations between covariates and plasma protein concentration were investigated using multiple linear regression models. The covariate with the greatest impact on the pTP concentration was the farm on which the calf was born (P<0.05). A significant but small association was demonstrated between colostrum immunoglobulin concentration and calf pTP concentration (P<0.01). Multiple linear regression models suggested that the time of colostrum collection after calving, parity of the dam, and the individual farm were associated with the Brix measurements (P<0.05). This study suggested that veterinary review of colostrum protocols on farm with emphasis on prompt collection and dosing after calving remains a simple and effective measure to improve passive transfer and thus calf health on UK dairy farms. PMID:25861824

  5. Ethrel-stimulated prolongation of latex flow in the rubber tree (Hevea brasiliensis Muell. Arg.): an Hev b 7-like protein acts as a universal antagonist of rubber particle aggregating factors from lutoids and C-serum.

    PubMed

    Shi, Min-Jing; Cai, Fu-Ge; Tian, Wei-Min

    2016-02-01

    Ethrel is the most effective stimuli in prolonging the latex flow that consequently increases yield per tapping. This effect is largely ascribed to the enhanced lutoid stability, which is associated with the decreased release of initiators of rubber particle (RP) aggregation from lutoid bursting. However, the increase in both the bursting index of lutoids and the duration of latex flow after applying ethrel or ethylene gas in high concentrations suggests that a new mechanism needs to be introduced. In this study, a latex allergen Hev b 7-like protein in C-serum was identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI TOF MS). In vitro analysis showed that the protein acted as a universal antagonist of RP aggregating factors from lutoids and C-serum. Ethrel treatment obviously weakened the effect of C-serum on RP aggregation, which was closely associated with the increase in the level of the Hev b 7-like protein and the decrease in the level of the 37 kDa protein, as revealed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), western blotting analysis and antibody neutralization. Thus, the increase of the Hev b 7-like protein level or the ratio of the Hev b 7-like protein to the 37 kDa protein in C-serum should be primarily ascribed to the ethrel-stimulated prolongation of latex flow duration. PMID:26381537

  6. Summarizing lecture: factors influencing enzymatic H-transfers, analysis of nuclear tunnelling isotope effects and thermodynamic versus specific effects

    PubMed Central

    Marcus, R.A

    2006-01-01

    In the articles in this Discussion, a wide variety of topics are treated, including reorganization energy, initially introduced for electron transfers (‘environmentally assisted tunnelling’), nuclear tunnelling, H/D and C12/C13 kinetic isotope effects (KIEs), the effect of changes of distal and nearby amino acid residues using site-directed mutagenesis, and dynamics versus statistical effects. A coordinate-free form of semi-classical theory is used to examine topics on data such as tunnelling versus ‘over-the-barrier’ paths and temperature and pressure effects on KIEs. The multidimensional semi-classical theory includes classically allowed and classically forbidden transitions. More generally, we address the question of relating kinetic to thermodynamic factors, as in the electron transfer field, so learning about specific versus thermodynamic effects in enzyme catalysis and KIEs. PMID:16873131

  7. The Use of Iteration Factors Method in the Solution of Multilevel Radiative Transfer Problems in Stellar Atmospheres

    NASA Astrophysics Data System (ADS)

    Kuzmanovska-Barandovska, O.

    2012-12-01

    The NLTE problem of formation of spectral lines is one of the most difficult ones to deal with; due to the important role of scattering processes it is nonlocal and for the multilevel case it is additionally nonlinear. Therefore, the problem requires simultaneous solution of radiative transfer (RT) and statistical equilibrium (SE) equations which can be achieved through iterative procedure. There is still a great need of efficient numerical methods for a solution of NLTE radiative transfer problems as they are a necessary step of stellar atmospheres modelling and other important astrophysical problems. In the thesis we develop fast and accurate numerical method that uses iteration factors. The method is based on the use of quasi-invariant functions - iteration factors, in a simple iterative procedure. Defined as ratios of the moments (integrals of angles and frequencies) of radiation field intensities, the factors are calculated on the beginning of each iterative step from the current solution and then used to obtain its correction. In the thesis we extend iteration factors method developed for a solution of linear problems - monochromatic problem and two-level atom line transfer problems to the solution of a more generalized multilevel problem of spectral line formation with complete redistribution and no background continuum. The additional difficulty arises from the non linear coupling of atomic level populations and the radiation filed intensities in the corresponding spectral lines. In the thesis we suggest and describe in details four iterative procedures that use two families of iteration factors defined for a constant property medium and two different approaches for a simultaneous solution of nonlinear RT and SE equations: (1) linearization of the equations with respect to all relevant variables and (2) modification of the SE equations in order to make them linear. In both approaches the substitution of the linearized SE equations in the moments of RT

  8. [Vascular endothelium as a factor in information transfer between the cardiovascular and immune systems].

    PubMed

    Stvrtinová, V; Ferencík, M; Hulín, I; Jahnová, E

    1998-01-01

    In health, the vascular endothelium forms a multifunctional interface between the circulating blood and various tissues and organs of the body. It constitutes a selectively permeable barrier for macromolecules, as well as a nonthrombogenic and nonadhesive container that actively maintains the fluidity of blood. It is a metabolically active endocrine organ, serving as the source of multiple factors and mediators that are critical for normal homeostasis. These include vasodilators (nitric oxide, prostacyclin, endothelium-derived hyperpolarizing factor), vasoconstrictors (endothelin-1, thromboxane A2, prostaglandin H2 and components of the renin angiotensin system), various pro- and antithrombotic factors (e.g. tissue factor, platelet activating factor--PAF, von Willebrand factor), fibrinolytic activators and inhibitors (e.g. tissue plasminogen activator, plasminogen activator inhibitor-1), potent arachidonate metabolites (prostanoids), leukocyte adhesion molecules (e.g. E-selectin, P-selectin, intercellular adhesion molecule-1--ICAM-1, vascular cell adhesion molecule-1--VCAM-1), and multiple cytokines with activities of growth stimulators and inhibitors, transforming growth factors, proinflammatory and antiinflammatory mediators, tumour necrosis factors and chemotactic factors (chemokines). Besides these essential activities controlling the cardiovascular system, the endothelial cells represent an important part of the immune system as well. They have a pivotal role in the initiation and development of defensive and damaging inflammatory responses. Therefore endothelium can be considered as being the central equipment for the mutual exchange of life important information between the cardiovascular and immune systems. This in turn is leading to rapid advances in understanding the pathogenesis of some of the most serious and most common diseases, including inflammation, atherosclerosis and hypertension. (Tab. 7, Ref. 89.) PMID:9588073

  9. Measurements of the elastic electromagnetic form factor ratio {mu}pGEp/GMp via polarization transfer

    SciTech Connect

    Olivier Gayou; Oleksandr Glamazdin; Andrei Afanasev; Arunava Saha; Brendan Fox; Bogdan Wojtsekhowski; C. Chang; Cathleen Jones; Charles Glashausser; Charles Perdrisat; D. Crovelli; Daniel Simon; David Meekins; Demetrius Margaziotis; Dipangkar Dutta; Edgar Kooijman; Elaine Schulte; Edward Brash; Edward Kinney; Eugene Chudakov; Feng Xiong; Franco Garibaldi; Garth Huber; Gerfried Kumbartzki; Guido Urciuoli; Haiyan Gao; Jordan Hovdebo; James Kelly; Javier Gomez; Jens-Ole Hansen; Jian-Ping Chen; John Calarco; John LeRose; Joseph Mitchell; Juncai Gao; Konrad Aniol; Kamal Benslama; Kathy McCormick; Cornelis De Jager; Cornelis de Jager; Kevin Fissum; Krishni Wijesooriya; Louis Bimbot; Ludyvine Morand; Luminita Todor; Moskov Amarian; Marat Rvachev; Mark Jones; Martin Epstein; Meihua Liang; Michael Kuss; Nilanga Liyanage; Adam Sarty; Paul Ulmer; Pete Markowitz; Peter Bosted; R. Holt; Riad Suleiman; Richard Lindgren; Rikki Roche; Robert Michaels; Roman Pomatsalyuk; Ronald Gilman; Ronald Ransome; Stephen Becher; Scott Dumalski; Salvatore Frullani; Seonho Choi; Sergey Malov; Sonja Dieterich; Steffen Strauch; Steve Churchwell; Ting Chang; Viktor Gorbenko; Vina Punjabi; Wang Xu; Xiangdong Ji; Zein-Eddine Meziani; Zhengwei Chai

    2001-09-01

    We present measurements of the ratio of the proton elastic electromagnetic form factors, {mu}pGEp/GMp. The Jefferson Lab Hall A Focal Plane Polarimeter was used to determine the longitudinal and transverse components of the recoil proton polarization in ep elastic scattering; the ratio of these polarization components is proportional to the ratio of the two form factors. These data reproduce the observation of Jones et al. [Phys. Rev. Lett. 84, 1398 (2000)], that the form factor ratio decreases significantly from unity above Q2 = 1 GeV2.

  10. Impact of plant and environmental factors on ALS-resistant gene transfer rate from ClearfieldTM rice to red rice biotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pollen-mediated transfer of ALS-resistant gene from ClearfieldTM (CL) rice to red rice can affect the population dynamics and long-term management of red rice. To mitigate gene flow, it is important to understand the plant and environmental factors which affect gene transfer rate. This experiment ai...

  11. Transfer of tumour necrosis factor-α via colostrum to foals.

    PubMed

    Secor, E J; Matychak, M B; Felippe, M J B

    2012-01-01

    This study aimed to determine whether TNF-α is transferred to equine neonates via colostrum and the relationship between TNF-α and IgG concentrations in the equine neonate. Colostrum, presuckle and postsuckle foal serum samples were collected from healthy mares and their foals. Equine TNF-α ELISA and IgG SRID kits were used to determine the concentrations of TNF-α and IgG, respectively. Statistical analysis was performed using the Spearman rank correlation. TNF-α concentrations in all presuckle foal serum were below the limit of detection in 15/16 foals and increased in postsuckle foal serum to a mean concentration of 7.7 x 10(4) pg/ml. TNF-α concentrations in postsuckle foal serum and colostrum showed significant correlation (rho=0.668; P=0.005). However, TNF-α and IgG concentrations in colostrum or postsuckle foal serum did not correlate (rho<-0.016; P>0.05). Ratios of TNF-α/IgG in colostrum or postsuckle foal serum showed significant correlation (rho=0.750; P=0.0008). These results indicate that TNF-α is transferred to the foal via colostrum absorption and may play a role in early immunity. PMID:22027187

  12. Therapeutic Protein Aggregation: Mechanisms, Design, and Control

    PubMed Central

    Roberts, Christopher J.

    2014-01-01

    While it is well known that proteins are only marginally stable in their folded states, it is often less well appreciated that most proteins are inherently aggregation-prone in their unfolded or partially unfolded states, and the resulting aggregates can be extremely stable and long-lived. For therapeutic proteins, aggregates are a significant risk factor for deleterious immune responses in patients, and can form via a variety of mechanisms. Controlling aggregation using a mechanistic approach may allow improved design of therapeutic protein stability, as a complement to existing design strategies that target desired protein structures and function. Recent results highlight the importance of balancing protein environment with the inherent aggregation propensities of polypeptide chains. PMID:24908382

  13. Transfer students in STEM majors at a Midwestern University: Academic and social involvement factors that influence student success

    NASA Astrophysics Data System (ADS)

    Lopez, Carlos

    There is soon-to-be a shortage of qualified U.S. workers in science, technology, engineering, and mathematics (STEM). As a result, many science-related jobs are being filled by technically-skilled foreign workers. If the U.S wants to maintain its global economic leadership, then it must ensure a continuous growth of highly-trained individuals in STEM disciplines. Therefore, American institutions of higher education, including community colleges, must identify potential factors that contribute to the lack of interest in STEM majors, as well as the low rate of success of students who enter STEM majors but struggle to finish their degrees. The purpose of this study was to ascertain the perceptions of community college transfer students who are pursuing bachelor degrees in STEM majors at Iowa State University (ISU). What were their transfer experiences and what influenced their academic success in STEM. Participants were encouraged to share their transfer experiences while at the community college as well as their experiences on the ISU campus. They were also asked about their level of academic involvement, their relationships with faculty, and their participation in peer group activities prior to and after transferring. The research design included both quantitative and qualitative components, which provided an in-depth look at the experiences of STEM non-engineering and engineering students. Quantitative data include students' background characteristics, demographic information, and college activities at the community college and ISU. Qualitative data were used to illuminate students' overall transfer experience and their successful journey in STEM fields. The combination of quantitative and qualitative methods allowed a better understanding of the strategies students put into practice once they transfer from a community college to a four-year institution in pursuit of a STEM bachelor's degree. The results of this study suggest that there is an association among the

  14. SiC MOSFET Based Single Phase Active Boost Rectifier with Power Factor Correction for Wireless Power Transfer Applications

    SciTech Connect

    Onar, Omer C; Tang, Lixin; Chinthavali, Madhu Sudhan; Campbell, Steven L; Miller , John M.

    2014-01-01

    Wireless Power Transfer (WPT) technology is a novel research area in the charging technology that bridges the utility and the automotive industries. There are various solutions that are currently being evaluated by several research teams to find the most efficient way to manage the power flow from the grid to the vehicle energy storage system. There are different control parameters that can be utilized to compensate for the change in the impedance due to variable parameters such as battery state-of-charge, coupling factor, and coil misalignment. This paper presents the implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation. The proposed SiC MOSFET based single phase active front end rectifier with PFC resulted in >97% efficiency at 137mm air-gap and >95% efficiency at 160mm air-gap.

  15. Oxygen Transport and Stem Cell Aggregation in Stirred-Suspension Bioreactor Cultures

    PubMed Central

    Wu, Jincheng; Rostami, Mahboubeh Rahmati; Cadavid Olaya, Diana P.; Tzanakakis, Emmanuel S.

    2014-01-01

    Stirred-suspension bioreactors are a promising modality for large-scale culture of 3D aggregates of pluripotent stem cells and their progeny. Yet, cells within these clusters experience limitations in the transfer of factors and particularly O2 which is characterized by low solubility in aqueous media. Cultured stem cells under different O2 levels may exhibit significantly different proliferation, viability and differentiation potential. Here, a transient diffusion-reaction model was built encompassing the size distribution and ultrastructural characteristics of embryonic stem cell (ESC) aggregates. The model was coupled to experimental data from bioreactor and static cultures for extracting the effective diffusivity and kinetics of consumption of O2 within mouse (mESC) and human ESC (hESC) clusters. Under agitation, mESC aggregates exhibited a higher maximum consumption rate than hESC aggregates. Moreover, the reaction-diffusion model was integrated with a population balance equation (PBE) for the temporal distribution of ESC clusters changing due to aggregation and cell proliferation. Hypoxia was found to be negligible for ESCs with a smaller radius than 100 µm but became appreciable for aggregates larger than 300 µm. The integrated model not only captured the O2 profile both in the bioreactor bulk and inside ESC aggregates but also led to the calculation of the duration that fractions of cells experience a certain range of O2 concentrations. The approach described in this study can be employed for gaining a deeper understanding of the effects of O2 on the physiology of stem cells organized in 3D structures. Such frameworks can be extended to encompass the spatial and temporal availability of nutrients and differentiation factors and facilitate the design and control of relevant bioprocesses for the production of stem cell therapeutics. PMID:25032842

  16. Oxygen transport and stem cell aggregation in stirred-suspension bioreactor cultures.

    PubMed

    Wu, Jincheng; Rostami, Mahboubeh Rahmati; Cadavid Olaya, Diana P; Tzanakakis, Emmanuel S

    2014-01-01

    Stirred-suspension bioreactors are a promising modality for large-scale culture of 3D aggregates of pluripotent stem cells and their progeny. Yet, cells within these clusters experience limitations in the transfer of factors and particularly O2 which is characterized by low solubility in aqueous media. Cultured stem cells under different O2 levels may exhibit significantly different proliferation, viability and differentiation potential. Here, a transient diffusion-reaction model was built encompassing the size distribution and ultrastructural characteristics of embryonic stem cell (ESC) aggregates. The model was coupled to experimental data from bioreactor and static cultures for extracting the effective diffusivity and kinetics of consumption of O2 within mouse (mESC) and human ESC (hESC) clusters. Under agitation, mESC aggregates exhibited a higher maximum consumption rate than hESC aggregates. Moreover, the reaction-diffusion model was integrated with a population balance equation (PBE) for the temporal distribution of ESC clusters changing due to aggregation and cell proliferation. Hypoxia was found to be negligible for ESCs with a smaller radius than 100 µm but became appreciable for aggregates larger than 300 µm. The integrated model not only captured the O2 profile both in the bioreactor bulk and inside ESC aggregates but also led to the calculation of the duration that fractions of cells experience a certain range of O2 concentrations. The approach described in this study can be employed for gaining a deeper understanding of the effects of O2 on the physiology of stem cells organized in 3D structures. Such frameworks can be extended to encompass the spatial and temporal availability of nutrients and differentiation factors and facilitate the design and control of relevant bioprocesses for the production of stem cell therapeutics. PMID:25032842

  17. Factors enhancing Agrobacterium tumefaciens-mediated gene transfer in peanut (Arachis hypogaea L.)

    NASA Technical Reports Server (NTRS)

    Egnin, M.; Mora, A.; Prakash, C. S.; Mortley, D. G. (Principal Investigator)

    1998-01-01

    Parameters enhancing Agrobacterium-mediated transfer of foreign genes to peanut (Arachis hypogaea L.) cells were investigated. An intron-containing beta-glucuronidase uidA (gusA) gene under the transcriptional control of CaMV 35S promoter served as a reporter. Transformation frequency was evaluated by scoring the number of sectors expressing GUS activity on leaf and epicotyl explants. The 'Valencia Select' market type cv. New Mexico was more amenable to Agrobacterium transformation than the 'runner' market type cultivars tested (Florunner, Georgia Runner, Sunrunner, or South Runner). The disarmed Agrobacterium tumefaciens strain EHA101 was superior in facilitating the transfer of uidA gene to peanut cells compared to the disarmed strain C58. Rinsing of explants in half-strength Murashige-Skoog (MS) media prior to infection by Agrobacterium significantly increased the transformation efficiency. The use of cocultivation media containing high auxin [1.0 or 2.5 mg/l (4.53 micromolar or 11.31 micromolar) 2,4-D] and low cytokinin [0.25 or 0.5 mg/l (1.0 micromolar or 2.0 micromolar) BA] promoted higher transformation than either hormone-free or thidiazuron-containing medium. The polarity of the epicotyl during cocultivation was important; explants incubated in an inverted (vertically) manner followed by a vertically upright position resulted in improved transformation and shoot regeneration frequencies. Preculture of explants in MS basal medium or with 2.5 mg thidiazuron per l prior to infection drastically decreased the number of transformed zones. The optimized protocol was used to obtain transient transformation frequencies ranging from 12% to 36% for leaf explants, 15% to 42% for epicotyls. Initial evidence of transformation was obtained by polymerase chain reaction and subsequently confirmed by Southern analysis of regenerated plants.

  18. JLab Measurement of the He4 Charge Form Factor at Large Momentum Transfers

    NASA Astrophysics Data System (ADS)

    Camsonne, A.; Katramatou, A. T.; Olson, M.; Sparveris, N.; Acha, A.; Allada, K.; Anderson, B. D.; Arrington, J.; Baldwin, A.; Chen, J.-P.; Choi, S.; Chudakov, E.; Cisbani, E.; Craver, B.; Decowski, P.; Dutta, C.; Folts, E.; Frullani, S.; Garibaldi, F.; Gilman, R.; Gomez, J.; Hahn, B.; Hansen, J.-O.; Higinbotham, D. W.; Holmstrom, T.; Huang, J.; Iodice, M.; Jiang, X.; Kelleher, A.; Khrosinkova, E.; Kievsky, A.; Kuchina, E.; Kumbartzki, G.; Lee, B.; LeRose, J. J.; Lindgren, R. A.; Lott, G.; Lu, H.; Marcucci, L. E.; Margaziotis, D. J.; Markowitz, P.; Marrone, S.; Meekins, D.; Meziani, Z.-E.; Michaels, R.; Moffit, B.; Norum, B.; Petratos, G. G.; Puckett, A.; Qian, X.; Rondon, O.; Saha, A.; Sawatzky, B.; Segal, J.; Shabestari, M.; Shahinyan, A.; Solvignon, P.; Subedi, R. R.; Suleiman, R.; Sulkosky, V.; Urciuoli, G. M.; Viviani, M.; Wang, Y.; Wojtsekhowski, B. B.; Yan, X.; Yao, H.; Zhang, W.-M.; Zheng, X.; Zhu, L.; Jefferson Lab Hall A Collaboration

    2014-04-01

    The charge form factor of He4 has been extracted in the range 29 fm-2≤Q2≤77 fm-2 from elastic electron scattering, detecting He4 recoil nuclei and electrons in coincidence with the high resolution spectrometers of the Hall A Facility of Jefferson Lab. The measurements have uncovered a second diffraction minimum for the form factor, which was predicted in the Q2 range of this experiment. The data are in qualitative agreement with theoretical calculations based on realistic interactions and accurate methods to solve the few-body problem.

  19. A Semi-Empirical Method to Estimate the Response Factors for VOCs in Proton-Transfer Reaction Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Li, S.; Leithead, A.; De Gouw, J. A.; Warneke, C.; Graus, M.; Veres, P. R.; Murphy, S. M.

    2013-12-01

    Volatile organic compounds are essential in sustaining atmospheric chemical processes which lie at the heart of most atmospheric environmental issues. Recent advances in VOC measurement technologies have allowed rapid detection of the primary VOCs and their oxidation products. Proton-Transfer-Reaction Mass Spectrometry (PTRMS) has been widely used to determine air concentrations of many hydrocarbons and oxygenated hydrocarbons rapidly. The recent advance in PTRMS with time-of-flight mass (TOF) detection, allows hundreds of VOC compounds to be detected simultaneously and rapidly. Converting these detected signals into air concentrations is a challenge. This is usually accomplished with calibrations using a limited number of target compounds at known concentrations. However, for the hundreds of masses in the PTR mass spectrum particularly from TOF detectors, conversion to air concentration is not always practical nor possible if their compound identities are not known. Here, we have developed a new method to estimate the response factors for VOCs to convert the measured ion signals into air concentrations. This method is based on semi-empirical calculations of the rate constants for the proton transfer reactions between the hydronium ion and target hydrocarbons using polarizabilities and permanent dipole moments, and extrapolation to unknown hydrocarbons. The method is further validated with calibration results for selected hydrocarbons. Using these response factors, conversion to air concentrations for many signals in a PTR MS of unknown chemical structures can be accomplished.

  20. Factors influencing ALS-resistant gene transfer from CL (tm) rice to red rice.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red rice (Oryza sativa L.) is hard to control due to its genetic similarity to cultivated rice. Herbicide-resistant Clearfield ™ (CL) rice now offers an excellent option for red rice control. However, sustainability of CL technology at the producers’ level will be dictated by various factors. Promi...

  1. Satisfaction Levels and Factors Influencing Satisfaction With Use of a Social App for Neonatal and Pediatric Patient Transfer Information Systems: A Questionnaire Study Among Doctors

    PubMed Central

    Choi, Iee; Kim, Sun Jun; Cho, Soo Chul; Kim, Il Nyeo

    2016-01-01

    Background The treatment of neonatal and pediatric patients is limited to certain medical institutions depending on treatment difficulty. Effective patient transfers are necessary in situations where there are limited medical resources. In South Korea, the government has made a considerable effort to establish patient transfer systems using various means, such as websites, telephone, and so forth. However, in reality, the effort has not yet been effective. Objective In this study, we ran a patient transfer information system using a social app for effective patient transfer. We analyzed the results, satisfaction levels, and the factors influencing satisfaction. Methods Naver Band is a social app and mobile community application which in Korea is more popular than Facebook. It facilitates group communication. Using Naver Band, two systems were created: one by the Neonatal Intensive Care Unit and the other by the Department of Pediatrics at Chonbuk National University Children's Hospital, South Korea. The information necessary for patient transfers was provided to participating obstetricians (n=51) and pediatricians (n=90). We conducted a survey to evaluate the systems and reviewed the results retrospectively. Results The number of patients transferred was reported to increase by 65% (26/40) obstetricians and 40% (23/57) pediatricians. The time taken for transfers was reported to decrease by 72% (29/40) obstetricians and 59% (34/57) pediatricians. Satisfaction was indicated by 83% (33/40) obstetricians and 89% (51/57) pediatricians. Regarding factors influencing satisfaction, the obstetricians reported communication with doctors in charge (P=.03) and time reduction during transfers (P=.02), whereas the pediatricians indicated review of the diagnosis and treatment of transferred patients (P=.01) and the time reduction during transfers (P=.007). Conclusions The users were highly satisfied and different users indicated different factors of satisfaction. This finding

  2. Brain-derived neurotrophic factor: subcellular compartmentalization and interneuronal transfer as visualized with anti-peptide antibodies.

    PubMed Central

    Wetmore, C; Cao, Y H; Pettersson, R F; Olson, L

    1991-01-01

    The recent cloning of a second member of the nerve growth factor family, brain-derived neurotrophic factor (BDNF), has prompted investigation into the cells that express this factor's mRNA and protein. In the present study, antibodies raised against unique peptide sequences within the porcine BDNF protein detect BDNF-like immunoreactivity in neurons in rat hippocampal and cortical areas consistent with the distribution of BDNF mRNA as detected with in situ hybridization. Within these neurons, BDNF-like immunoreactivity was observed in the cytoplasm, dendrites, and nuclei. In addition, BDNF immunoreactivity was observed in the cytoplasm of cholinergic neurons that do not express detectable levels of BDNF mRNA. Thus, anti-peptide antibodies can be used to detect this neurotrophic factor protein in cytoplasmic sites of synthesis and in areas of probable action. We propose that one form of the BDNF protein enters the nucleus and may directly influence transcription, while another fraction of the protein is transported out of the synthesizing cell and can be detected, after retrograde axonal transport, in cytoplasmic granules in the perikarya of cholinergic neurons. These basal forebrain cholinergic neurons project to regions enriched in BDNF-synthesizing cells and are known to be responsive to BDNF in vitro. Our data provide information regarding the cellular distribution of BDNF protein in vivo and suggest a dendro-axonic interneuronal transfer of BDNF as well as an additional, intracellular signaling pathway not previously thought to occur in postmitotic neurons in brain. Images PMID:1946410

  3. Aggregations in Flatworms.

    ERIC Educational Resources Information Center

    Liffen, C. L.; Hunter, M.

    1980-01-01

    Described is a school project to investigate aggregations in flatworms which may be influenced by light intensity, temperature, and some form of chemical stimulus released by already aggregating flatworms. Such investigations could be adopted to suit many educational levels of science laboratory activities. (DS)

  4. Factors affecting stepladder stability during a lateral weight transfer: a study in healthy young adults.

    PubMed

    Yang, Bing-Shiang; Ashton-Miller, James A

    2005-09-01

    A fall from a stepladder is often initiated by a loss of lateral stability. An inverted pendulum model of the human, validated by experiment, was used to determine the feasible range of whole-body center of mass (COM) states for which weight can be transferred laterally on a ladder tread without a ladder rail losing contact with the ground ("no lift-off" stability region). The results show that the size of the feasible no lift-off region was inversely proportional to the height of the tread above the ground, the distance of the stance foot from the ipsilateral rail, and lateral ground inclination angle. For given initial COM kinematics on a tread height equal to 40% human body height, a stance-foot location equal to one-eighth tread width and a 3.5 degrees ground inclination had approximately equivalent effects on the no lift-off region size. Ladder stability was three times more sensitive to tread height than to foot location. Laterally-exerted impulsive hand-tool forces should generally be limited to 8% body weight. These findings can lead to improved ladder designs and safety instructions for stepladder users. PMID:15970205

  5. Characterization of human dialyzable transfer factor from normal and chronic lymphoid leukemia sources.

    PubMed

    Goust, J M; Marescot, M R; Lesourd, B; Doumercq, S; Moulias, R

    1976-01-01

    Dialysates of lymphomonocytes can be roughly quantified through the use of optical density and measurements of RNA and protein contents. Dialysates of normal lymphocytes (N-TFd) contain about 224 +/- 67 mug of RNA-like material per 10(8) cells, 75 to 90% of which is eluted in fractions II and III on Biogel P10 chromatography. In contrast, dialysates of lymphocytes from patients suffering chronic lymphoid leukemia (CLL-TFd) contain approximately 12 times less RNA-like material (about 27 +/- 11 mug per 10(8) lymphocytes) and have a different characteristic chromatographic pattern. Bioassays with crude dialysates confirm (a) that N-TFd increases 3H-thymidine incorporation by nonsenstitized lymphocytes "in vitro" in the presence of PPD, and (b) that inbred Lewis rats develop positive skin tests (systemic transfer) after receiving injections of N-TFd or of fractions II and III from Biogel fractionation of N-TFd. Neither test gives positive results when CLL-TFd is used. PMID:817750

  6. Antiplatelet aggregation principles from Ephemerantha lonchophylla.

    PubMed

    Chen, C C; Huang, Y L; Teng, C M

    2000-05-01

    Bioactivity-directed separation led to the identification of four compounds, viz. denbinobin (1), 3,7-dihydroxy-2,4-dimethoxyphenanthrene (2), 3-methylgigantol (3), and erianthridin (4) from the ethanolic extract of Ephemerantha lonchophylla. Antiplatelet tests were carried out using 4 different aggregation inducers, viz. arachidonic acid (AA), thrombin, collagen and platelet activating factor (PAF). The results indicated that only compounds 2, 3, and 4 exhibited generally significant anti-aggregation activities with that against AA-induced aggregation being most effective. Estimated IC50, values in this regard for 2, 3, and 4 were 24 microM, 30 microM and 9 microM, respectively. PMID:10865460

  7. Biological framework for soil aggregation: Implications for ecological functions.

    NASA Astrophysics Data System (ADS)

    Ghezzehei, Teamrat; Or, Dani

    2016-04-01

    Soil aggregation is heuristically understood as agglomeration of primary particles bound together by biotic and abiotic cementing agents. The organization of aggregates is believed to be hierarchical in nature; whereby primary particles bond together to form secondary particles and subsequently merge to form larger aggregates. Soil aggregates are not permanent structures, they continuously change in response to internal and external forces and other drivers, including moisture, capillary pressure, temperature, biological activity, and human disturbances. Soil aggregation processes and the resulting functionality span multiple spatial and temporal scales. The intertwined biological and physical nature of soil aggregation, and the time scales involved precluded a universally applicable and quantifiable framework for characterizing the nature and function of soil aggregation. We introduce a biophysical framework of soil aggregation that considers the various modes and factors of the genesis, maturation and degradation of soil aggregates including wetting/drying cycles, soil mechanical processes, biological activity and the nature of primary soil particles. The framework attempts to disentangle mechanical (compaction and soil fragmentation) from in-situ biophysical aggregation and provides a consistent description of aggregate size, hierarchical organization, and life time. It also enables quantitative description of biotic and abiotic functions of soil aggregates including diffusion and storage of mass and energy as well as role of aggregates as hot spots of nutrient accumulation, biodiversity, and biogeochemical cycles.

  8. Characterization of a myeloma patient with a life-threatening hemorrhagic diathesis: presence of a lambda dimer protein inhibiting shear-induced platelet aggregation by binding to the A1 domain of von Willebrand factor.

    PubMed

    Shinagawa, Atsushi; Kojima, Hiroshi; Berndt, Michael C; Kaneko, Shin; Suzukawa, Kazumi; Hasegawa, Yuichi; Shigeta, Osamu; Nagasawa, Toshiro

    2005-05-01

    We have identified a patient with IgD lambda-type multiple myeloma who was characterized by a severe bleeding tendency, especially after puncture of arterial vessels. Both the bleeding time (>25 min) and activated partial thromboplastin time (APTT) were prolonged. To clarify the underlying pathogenesis, we purified the APTT-prolonging activity from the patient's serum. The purified protein was a highly negatively-charged homodimer of the lambda light chain. The lambda dimer protein (M-protein) inhibited ristocetinand high shear-induced platelet aggregation, dependent on platelet glycoprotein Ibalpha (GPIbalpha), but not epinephrine-, collagen-, ADP-, thrombin-, or botrocetin-induced platelet aggregation. The lambda dimer protein inhibited the binding of platelets to immobilized or ristocetin-treated von Willebrand factor (VWF). Furthermore, a 39/34 kD fragment of VWF encompassing the A1 domain specifically bound to the immobilized lambda dimer protein in the presence of ristocetin, suggesting that the lambda dimer protein directly binds to the A1 domain of VWF. To help elucidate the binding site within the A1 domain, binding of ristocetin-treated VWF to the immobilized lambda dimer protein was assayed in the presence of various anti-A1 domain monoclonal antibodies. Based on these data, we conclude that the lambda dimer protein binds to the region of the A1 domain composed of helices alpha3 and alpha4 and thus interferes with VWF-GPIbalpha interaction. The existence of a protein that inhibits high shear-induced platelet aggregation in acquired von Willebrand disease (VWD) has only rarely been reported. The results suggest that the hemostatic function in arteries with high shear force is profoundly disrupted if the binding of GPIbalpha to VWF is abrogated, supporting the relevance of shear-induced VWF interaction with GPIbalpha in the initiation of the hemostatic process. PMID:15886805

  9. Transference and "the Rebbe" idiographic and nomothetic factors in the psychoanalysis of Lubavitch Chassidim.

    PubMed

    Schulman, Martin A; Kaplan, Ricki S

    2013-12-01

    The Lubavitch Chassidim are one of several ultra-orthodox groups within Judaism. Their central focus is on their leader or Rebbe, who is seen as not only the possessor of all wisdom but also having supernatural powers. In working therapeutically with Lubavitch, one needs to distinguish if the beliefs of the individual are unique to them or reflect the belief system of the community. If the former, then it obviously needs to be analyzed. If the latter, then it is seen as an identification with the group and reflective of the need for group cohesion and often a regulator of self-esteem. The following article demonstrates these factors. PMID:23824957

  10. Scattering cross-section emission factors for visibility and radiative transfer applications: military vehicles traveling on unpaved roads.

    PubMed

    Moosmüller, Hans; Varma, Ravi; Arnott, W Patrick; Kuhns, Hampden D; Etyemezian, Vicken; Gillies, John A

    2005-11-01

    Emission factors for particulate matter (PM) are generally reported as mass emission factors (PM mass emitted per time or activity) as appropriate for air quality standards based on mass concentration. However, for visibility and radiative transfer applications, scattering, absorption, and extinction coefficients are the parameters of interest, with visibility standards based on extinction coefficients. These coefficients (dimension of inverse distance) equal cross-section concentrations, and, therefore, cross-section emission factors are appropriate. Scattering cross-section emission factors were determined for dust entrainment by nine vehicles, ranging from light passenger vehicles to heavy military vehicles, traveling on an unpaved road. Each vehicle made multiple passes at multiple speeds while scattering and absorption coefficients, wind velocity and dust plume profiles, and additional parameters were measured downwind of the road. Light absorption of the entrained PM was negligible, and the light extinction was primarily caused by scattering. The resulting scattering cross-section emission factors per vehicle kilometer traveled (vkt) range from 12.5 m2/vkt for a slow (16 km/ hr), light (1176 kg) vehicle to 3724 m2/vkt for a fast (64 km/hr), heavy (17,727 kg) vehicle and generally increase with vehicle speed and mass. The increase is approximately linear with speed, yielding emission factors per vkt and speed ranging from 4.2 m2/(vkt km/hr) to 53 m2/(vkt km/hr). These emission factors depend approximately linearly on vehicle mass within the groups of light (vehicle mass < or =3100 kg) and heavy (vehicle mass >8000 kg) vehicles yielding emission factors per vkt, speed, and mass of 0.0056 m2/(vkt km/hr kg) and 0.0024 m2/(vkt km/hr kg), respectively. Comparison of the scattering cross-section and PM mass emission factors yields average mass scattering efficiencies of 1.5 m2/g for the light vehicles and of 0.8 m2/g for the heavy vehicles indicating that the heavy

  11. Physiological mechanisms, behavioral and psychological factors influencing the transfer of milk from mothers to their young.

    PubMed

    Jonas, Wibke; Woodside, Barbara

    2016-01-01

    This article is part of a Special Issue "Parental Care".Producing milk to support the growth of their young is a central element of maternal care in mammals. In spite of the facts that ecological constraints influence nursing frequency, length of time until weaning and the composition of milk, there is considerable similarity in the anatomy and physiology of milk production and delivery across mammalian species. Here we provide an overview of cross species variation in nursing patterns and milk composition as well as the mechanisms underlying mammary gland development, milk production and letdown. Not all women breastfeed their infants, thus in later sections we review studies of factors that facilitate or impede the initiation and duration of breastfeeding. The results of these investigations suggest that the decisions to initiate and maintain breastfeeding are influenced by an array of personal, social and biological factors. Finally, studies comparing the development of breastfed and formula fed infants as well as those investigating associations between breastfeeding, maternal health and mother/infant interaction are reviewed. Leading health agencies including the World Health Organization and CDC advocate breastfeeding for at least the first 6months postpartum. To achieve these rates will require not only institutional support but also a focus on individual mother/infant dyads and their experience. PMID:26232032

  12. Influence of Phenylalanine on Carotenoid Aggregation

    NASA Astrophysics Data System (ADS)

    Lu, L.; Ni, X.; Luo, X.

    2015-01-01

    The carotenoids lutein and β-carotene form, in 1:1 ethanol-water mixtures H-aggregates, of different strengths. The effects of phenylalanine on these aggregates were recorded by UV-Vis absorption, steady-state fluorescence, and Raman spectra. The H-aggregate of lutein was characterized by a large 78 nm blue shift in the absorption spectra, confirming the strong coupling between hydroxyl groups of adjacent molecules. The 15 nm blue shift in the β-carotene mixture also indicates that it was assembled by weak coupling between polyenes. After adding phenylalanine, the reducing absorption strength of the aggregates of lutein and reappearance of vibrational substructure indicate that the hydroxyl and amino groups of phenylalanine may coordinate to lutein and disaggregate the H-aggregates. However, phenylalanine had no effect on aggregates of β-carotene. The Raman spectra show three bands of carotenoids whose intensities decreased with increasing phenylalanine concentration. The frequency of ν1 corresponding to the length of the conjugated region was more sensitive to the solution of lutein. This coordination of phenylalanine to lutein could increase the length of the conjugated region. In addition, phenylalanine significantly affected the excited electronic states of carotenoids, which were crucial in the energy transfer from carotenoids to chlorophyll a in vivo.

  13. Two protocols to treat thin endometrium with granulocyte colony-stimulating factor during frozen embryo transfer cycles.

    PubMed

    Xu, Bin; Zhang, Qiong; Hao, Jie; Xu, Dabao; Li, Yanping

    2015-04-01

    The efficacy of two granulocyte colony-stimulating factor (G-CSF) protocols for thin endometrium were investigated. Eighty-two patients were diagnosed with thin endometrium (<7 mm). Thirty patients with previously cancelled embryo transfers received intrauterine G-CSF in subsequent frozen embryo transfer (FET) cycles. Patients were divided into the G-CSF only and G-CSF with endometrial scratch subgroups. Compared with previous cycles, endometrial thickness increased from 5.7 ± 0.7 mm to 8.1 ± 2.1 mm after G-CSF treatment (P < 0.001). Endometrial thickness increases were not significantly different between the two subgroups. The G-CSF with endometrial scratch subgroup established nominally higher though non-significant clinical pregnancy and live birth rates than the G-CSF only subgroup (53.8 % versus 42.9% and 38.5% versus 28.6%, respectively). Fifty-two patients underwent FET despite edometrial thickness less than 7 mm, and were included as controls. Significantly higher embryo implantation and clinical pregnancy rates were observed in the G-CSF group compared with the control group (31.5% versus 13.9%; P < 0.01; 48.1% versus 25.0%; P = 0.038, respectively). Endometrial scracth did not impair G-CSF treatment for thin endometrium and favoured pregnancy and live birth rates. For patients with thin endometrium, embryo transfer cancellation and G-CSF treatment in subsequent FET cycles is beneficial. PMID:25682303

  14. Combined factors influencing the aggregation and deposition of nano-TiO2 in the presence of humic acid and bacteria.

    PubMed

    Chowdhury, Indranil; Cwiertny, David M; Walker, Sharon L

    2012-07-01

    This study investigates the contributions of natural organic matter (NOM) and bacteria to the aggregation and deposition of TiO(2) nanoparticles (TNPs) in aquatic environments. Transport experiments with TNPs were conducted in a microscopic parallel plate system and a macroscopic packed-bed column using fluorescently tagged E. coli as a model organism and Suwannee River Humic Acid as a representative NOM. Notably, TNPs were labeled with fluorescein isothiocyanate allowing particles and cells to be simultaneously visualized with a fluorescent microscope. Results from both experimental systems revealed that interactions among TNPs, NOM, and bacteria exhibited a significant dependence on solution chemistry (pH 5 and 7) and ion valence (K(+) and Ca(2+)), and that these interactions subsequently affect TNPs deposition. NOM and E. coli significantly reduced deposition of TNPs, with NOM having a greater stabilizing influence than bacteria. Ca(2+) ions played a significant role in these interactions, promoting formation of large clusters of TNPs, NOM, and bacteria. TNPs transport in the presence of both NOM and E. coli resulted in much less deposition than in the presence of NOM or E. coli alone, indicating a complex combination of interactions involved in stabilization. Generally, over the aquatic conditions considered, the extent of TNPs deposition follows: without NOM or bacteria > with bacteria only > with NOM only > combined bacteria and NOM. This trend should allow better prediction of the fate of TNPs in complex aquatic systems. PMID:22455349

  15. Trichostatin A specifically improves the aberrant expression of transcription factor genes in embryos produced by somatic cell nuclear transfer

    PubMed Central

    Inoue, Kimiko; Oikawa, Mami; Kamimura, Satoshi; Ogonuki, Narumi; Nakamura, Toshinobu; Nakano, Toru; Abe, Kuniya; Ogura, Atsuo

    2015-01-01

    Although mammalian cloning by somatic cell nuclear transfer (SCNT) has been established in various species, the low developmental efficiency has hampered its practical applications. Treatment of SCNT-derived embryos with histone deacetylase (HDAC) inhibitors can improve their development, but the underlying mechanism is still unclear. To address this question, we analysed gene expression profiles of SCNT-derived 2-cell mouse embryos treated with trichostatin A (TSA), a potent HDAC inhibitor that is best used for mouse cloning. Unexpectedly, TSA had no effect on the numbers of aberrantly expressed genes or the overall gene expression pattern in the embryos. However, in-depth investigation by gene ontology and functional analyses revealed that TSA treatment specifically improved the expression of a small subset of genes encoding transcription factors and their regulatory factors, suggesting their positive involvement in de novo RNA synthesis. Indeed, introduction of one of such transcription factors, Spi-C, into the embryos at least partially mimicked the TSA-induced improvement in embryonic development by activating gene networks associated with transcriptional regulation. Thus, the effects of TSA treatment on embryonic gene expression did not seem to be stochastic, but more specific than expected, targeting genes that direct development and trigger zygotic genome activation at the 2-cell stage. PMID:25974394

  16. Trichostatin A specifically improves the aberrant expression of transcription factor genes in embryos produced by somatic cell nuclear transfer.

    PubMed

    Inoue, Kimiko; Oikawa, Mami; Kamimura, Satoshi; Ogonuki, Narumi; Nakamura, Toshinobu; Nakano, Toru; Abe, Kuniya; Ogura, Atsuo

    2015-01-01

    Although mammalian cloning by somatic cell nuclear transfer (SCNT) has been established in various species, the low developmental efficiency has hampered its practical applications. Treatment of SCNT-derived embryos with histone deacetylase (HDAC) inhibitors can improve their development, but the underlying mechanism is still unclear. To address this question, we analysed gene expression profiles of SCNT-derived 2-cell mouse embryos treated with trichostatin A (TSA), a potent HDAC inhibitor that is best used for mouse cloning. Unexpectedly, TSA had no effect on the numbers of aberrantly expressed genes or the overall gene expression pattern in the embryos. However, in-depth investigation by gene ontology and functional analyses revealed that TSA treatment specifically improved the expression of a small subset of genes encoding transcription factors and their regulatory factors, suggesting their positive involvement in de novo RNA synthesis. Indeed, introduction of one of such transcription factors, Spi-C, into the embryos at least partially mimicked the TSA-induced improvement in embryonic development by activating gene networks associated with transcriptional regulation. Thus, the effects of TSA treatment on embryonic gene expression did not seem to be stochastic, but more specific than expected, targeting genes that direct development and trigger zygotic genome activation at the 2-cell stage. PMID:25974394

  17. Charged Dust Aggregate Interactions

    NASA Astrophysics Data System (ADS)

    Matthews, Lorin; Hyde, Truell

    2015-11-01

    A proper understanding of the behavior of dust particle aggregates immersed in a complex plasma first requires a knowledge of the basic properties of the system. Among the most important of these are the net electrostatic charge and higher multipole moments on the dust aggregate as well as the manner in which the aggregate interacts with the local electrostatic fields. The formation of elongated, fractal-like aggregates levitating in the sheath electric field of a weakly ionized RF generated plasma discharge has recently been observed experimentally. The resulting data has shown that as aggregates approach one another, they can both accelerate and rotate. At equilibrium, aggregates are observed to levitate with regular spacing, rotating about their long axis aligned parallel to the sheath electric field. Since gas drag tends to slow any such rotation, energy must be constantly fed into the system in order to sustain it. A numerical model designed to analyze this motion provides both the electrostatic charge and higher multipole moments of the aggregate while including the forces due to thermophoresis, neutral gas drag, and the ion wakefield. This model will be used to investigate the ambient conditions leading to the observed interactions. This research is funded by NSF Grant 1414523.

  18. JLab Measurement of the 4He Charge Form Factor at Large Momentum Transfers

    SciTech Connect

    Camsonne, Alexandre; Katramatou, A. T.; Olson, M.; Sparveris, Nikolaos; Acha, Armando; Allada, Kalyan; Anderson, Bryon; Arrington, John; Baldwin, Alan; Chen, Jian-Ping; Choi, Seonho; Chudakov, Eugene; Cisbani, Evaristo; Craver, Brandon; Decowski, Piotr; Dutta, Chiranjib; Folts, Edward; Frullani, Salvatore; Garibaldi, Franco; Gilman, Ronald; Gomez, Javier; Hahn, Brian; Hansen, Jens-Ole; Higinbotham, Douglas; Holmstrom, Timothy; Huang, Jian; Iodice, Mauro; Kelleher, Aidan; Khrosinkova, Elena; Kievsky, A.; Kuchina, Elena; Kumbartzki, Gerfried; Lee, Byungwuek; LeRose, John; Lindgren, Richard; Lott, Gordon; Lu, H.; Marcucci, Laura; Margaziotis, Demetrius; Markowitz, Pete; Marrone, Stefano; Meekins, David; Meziani, Zein-Eddine; Michaels, Robert; Moffit, Bryan; Norum, Blaine; Petratos, Gerassimos; Puckett, Andrew; Qian, Xin; Rondon-Aramayo, Oscar; Saha, Arunava; Sawatzky, Bradley; Segal, John; Hashemi, Mitra; Shahinyan, Albert; Solvignon-Slifer, Patricia; Subedi, Ramesh; Suleiman, Riad; Sulkosky, Vincent; Urciuoli, Guido; Viviani, Michele; Wang, Y.; Wojtsekhowski, Bogdan; Yan, X.; Yao, H.; Zhang, W. -M.; Zheng, X.; Zhu, L.

    2014-04-01

    The charge form factor of 4He has been extracted in the range 29 fm-2 <= Q2 <= 77 fm-2 from elastic electron scattering, detecting 4He nuclei and electrons in coincidence with the High Resolution Spectrometers of the Hall A Facility of Jefferson Lab. The results are in qualitative agreement with realistic meson-nucleon theoretical calculations. The data have uncovered a second diffraction minimum, which was predicted in the Q2 range of this experiment, and rule out conclusively long-standing predictions of dimensional scaling of high-energy amplitudes using quark counting.

  19. Aggregate and the environment

    USGS Publications Warehouse

    Langer, William H.; Drew, Lawrence J.; Sachs, J.S.

    2004-01-01

    This book is designed to help you understand our aggregate resources-their importance, where they come from, how they are processed for our use, the environmental concerns related to their mining and processing, how those concerns are addressed, and the policies and regulations designed to safeguard workers, neighbors, and the environment from the negative impacts of aggregate mining. We hope this understanding will help prepare you to be involved in decisions that need to be made-individually and as a society-to be good stewards of our aggregate resources and our living planet.

  20. A method to rapidly create protein aggregates in living cells

    PubMed Central

    Miyazaki, Yusuke; Mizumoto, Kota; Dey, Gautam; Kudo, Takamasa; Perrino, John; Chen, Ling-chun; Meyer, Tobias; Wandless, Thomas J.

    2016-01-01

    The accumulation of protein aggregates is a common pathological hallmark of many neurodegenerative diseases. However, we do not fully understand how aggregates are formed or the complex network of chaperones, proteasomes and other regulatory factors involved in their clearance. Here, we report a chemically controllable fluorescent protein that enables us to rapidly produce small aggregates inside living cells on the order of seconds, as well as monitor the movement and coalescence of individual aggregates into larger structures. This method can be applied to diverse experimental systems, including live animals, and may prove valuable for understanding cellular responses and diseases associated with protein aggregates. PMID:27229621

  1. Variability of the soil-to-plant radiocaesium transfer factor for Japanese soils predicted with soil and plant properties.

    PubMed

    Uematsu, Shinichiro; Vandenhove, Hildegarde; Sweeck, Lieve; Van Hees, May; Wannijn, Jean; Smolders, Erik

    2016-03-01

    Food chain contamination with radiocaesium (RCs) in the aftermath of the Fukushima accident calls for an analysis of the specific factors that control the RCs transfer. Here, soil-to-plant transfer factors (TF) of RCs for grass were predicted from the potassium concentration in soil solution (mK) and the Radiocaesium Interception Potential (RIP) of the soil using existing mechanistic models. The mK and RIP were (a) either measured for 37 topsoils collected from the Fukushima accident affected area or (b) predicted from the soil clay content and the soil exchangeable potassium content using the models that had been calibrated for European soils. An average ammonium concentration was used throughout in the prediction. The measured RIP ranged 14-fold and measured mK varied 37-fold among the soils. The measured RIP was lower than the RIP predicted from the soil clay content likely due to the lower content of weathered micas in the clay fraction of Japanese soils. Also the measured mK was lower than that predicted. As a result, the predicted TFs relying on the measured RIP and mK were, on average, about 22-fold larger than the TFs predicted using the European calibrated models. The geometric mean of the measured TFs for grass in the affected area (N = 82) was in the middle of both. The TFs were poorly related to soil classification classes, likely because soil fertility (mK) was obscuring the effects of the soil classification related to the soil mineralogy (RIP). This study suggests that, on average, Japanese soils are more vulnerable than European soils at equal soil clay and exchangeable K content. The affected regions will be targeted for refined model validation. PMID:26717351

  2. Intramyocardial transfer of hepatocyte growth factor as an adjunct to CABG: phase I clinical study.

    PubMed

    Kim, J S; Hwang, H Y; Cho, K R; Park, E-A; Lee, W; Paeng, J C; Lee, D S; Kim, H-K; Sohn, D-W; Kim, K-B

    2013-07-01

    The purpose of this phase I clinical trial was to evaluate the safety, tolerability and potential efficacy of VM202, naked DNA expressing two isoforms of hepatocyte growth factor, as an adjunct therapy to coronary artery bypass grafting (CABG) in patients with ischemic heart disease (IHD). Nine patients were assigned to receive increasing doses (0.5 to 2.0 mg) of VM202 injected into the right coronary artery (RCA) territory following completion of CABG for the left coronary artery territory. Patients were evaluated for safety and tolerability, and changes in myocardial functions were monitored via echocardiography, cardiac magnetic resonance imaging and myocardial single photon emission computed tomography throughout 6-month follow-up period. No serious complication related to VM202 was observed throughout the 6-month follow-up period. Global myocardial functions (wall motion score index, P=0.0084; stress perfusion, P=0.0002) improved during the follow-up period. In the RCA region, there was an increase in the stress perfusion (baseline vs 3-month, P=0.024; baseline vs 6-month, P=0.024) and also in the wall thickness of the diastolic and systolic phases. Intramyocardial injection of VM202 can be safely used in IHD patients with the tolerable dose of 2.0 mg. In addition, VM202 might appear to have improved regional myocardial perfusion and wall thickness in the injected region. PMID:23151518

  3. Human transfer factor in vitro. II. Augmentation of the secretion of leucocyte migration inhibitory factor (LIF) by leucocyte dialysate and by its components L-serine and glycine.

    PubMed Central

    Ashorn, R G; Räsänen, L; Marnela, K M; Krohn, K J

    1979-01-01

    The effect of human transfer factor (TF) or its components L-serine and/or glycine in tuberculin (PPD), or leucoagglutinin (LA) induced leucocyte migration inhibitory factor (LIF) secretion was studied. Augmentation of LIF secretion was seen with low concentration ( = 0.078 g/l) of TF when lymphocytes were cultured in minimum essential medium for suspension cultures (MEM-S), a culture medium lacking L-serine and glycine. High concentrations (0.3125-5.0 g/l dry weight) of TF were inhibitory in MEM-S. In RPMI 1640, a culture medium containing L-serine and glycine, TF was either inhibitory or had no effect. The combination of L-serine and glycine, at concentrations equivalent or lower than the optimum of TF, had an augmenting effect on LIF secretion identical to that of TF, but no inhibition at higher concentrations was seen. The results indicate that human TF contains components which have suppressive or augmenting effects on LIF secretion in vitro. The augmenting effect may be mainly due to L-serine and glycine and thus not related to TF's activity in vivo. PMID:385187

  4. Development of a general equation to determine the transfer factor feed-to-meat for radiocesium on the basis of the body mass of domestic animals

    SciTech Connect

    Nalezinski, S.; Ruehm, W.; Wirth, E.

    1996-05-01

    Transfer factors from feed to meat (5{sub {integral}}), taken from literature for monogastric animals and ruminants have been correlated to their corresponding animal body mass (m{sub b}). Taking all data into account, a close relationship between both transfer factor and body mass becomes evident, yielding a regression function of (T{sub {integral}} = 8.0 x m{sub b}{sup {minus}0.91}) (r = -0.97). For monogastric animals (including poultry), the corresponding relationships are T{sub {integral}} = 1.9 x m{sub b}{sup {minus}0.72} (r = 0.78). The equations offer the opportunity to estimate the transfer factor for individual animals more precisely taking individual body masses into account. They are of interest for animals, on which no or only poor data concerning radiocesium transfer factors are available. The determination of radiocesium transfer factors are reduced to a simple weighing process. 17 refs., 1 fig., 2 tabs.

  5. Protein Colloidal Aggregation Project

    NASA Technical Reports Server (NTRS)

    Oliva-Buisson, Yvette J. (Compiler)

    2014-01-01

    To investigate the pathways and kinetics of protein aggregation to allow accurate predictive modeling of the process and evaluation of potential inhibitors to prevalent diseases including cataract formation, chronic traumatic encephalopathy, Alzheimer's Disease, Parkinson's Disease and others.

  6. Structural and Formulation Factors Influencing Pyridinium Lipid-based Gene Transfer

    PubMed Central

    Zhu, Lin; Lu, Yan; Miller, Duane D.; Mahato, Ram I.

    2009-01-01

    A series of pyridinium lipids containing a heterocyclic ring and a nitrogen atom were synthesized to determine the structure-activity relationship for gene delivery. Pyrylium chloroaluminate was synthesized by monoacylation of mesityl oxide and converted into pyrylium hexafluorophosphate, which was used as the key intermediate for reaction with different primary amines, to yield hydroxyethylpyridinium hexafluorophosphate and aminoethylpyridinium hexafluorophosphate. Acylation of these pyridinium salts with different types of fatty acid chlorides afforded the final pyridinium lipids, which were mixed with a co-lipid, such as L-alpha-dioleoylphosphatidylethanolamine (DOPE) and cholesterol (Chol) to prepare cationic liposomes by sonication. These liposomes were mixed with plasmid DNA encoding enhanced green fluorescent protein (pCMS-EGFP) or luciferase (pDNA3-Luc) and transfected into Chinese Hamster Ovary (CHO) cells. Several factors including hydrophobic anchor chain length, anchor chain type, configuration of double bond, linker type, co-lipid type, cationic lipid: co-lipid molar ratio, charge ratio (N/P), and cell type had significant influence on transfection efficiency and cytotoxicity. Pyridinium lipids with amide linker showed significantly higher transfection efficiency compared to their ester counterparts. Liposomes prepared at 1:1 molar ratio of pyridinium lipid and co-lipid showed higher transfection efficiency when either DOPE or cholesterol was used as a co-lipid to prepare cationic liposomes for complex formation with plasmid DNA at 3:1(+/−) charge ratio. Pyridinium liposomes based on hydrophobic anchor chain length of 16 showed higher transfection efficiency and lower cytotoxicity. The pyridinium lipid with trans-configuration of the double bond in fatty acid chain showed higher transfection efficiency than its counterpart with cis-configuration at the same fatty acid chain length. In the presence of serum, C16:0 and Lipofectamine significantly

  7. Silt-clay aggregates on Mars

    NASA Technical Reports Server (NTRS)

    Greeley, R.

    1979-01-01

    Viking observations suggest abundant silt and clay particles on Mars. It is proposed that some of these particles agglomerate to form sand size aggregates that are redeposited as sandlike features such as drifts and dunes. Although the binding for the aggregates could include salt cementation or other mechanisms, electrostatic bonding is considered to be a primary force holding the aggregates together. Various laboratory experiments conducted since the 19th century, and as reported here for simulated Martian conditions, show that both the magnitude and sign of electrical charges on windblown particles are functions of particle velocity, shape and composition, atmospheric pressure, atmospheric composition and other factors. Electrical charges have been measured for saltating particles in the wind tunnel and in the field, on the surfaces of sand dunes, and within dust clouds on earth. Similar, and perhaps even greater, charges are proposed to occur on Mars, which could form aggregates of silt and clay size particles

  8. Protein aggregation and misfolding: good or evil?

    NASA Astrophysics Data System (ADS)

    Pastore, Annalisa; Temussi, Pierandrea

    2012-06-01

    Protein aggregation and misfolding have important implications in an increasing number of fields ranging from medicine to biology to nanotechnology and material science. The interest in understanding this field has accordingly increased steadily over the last two decades. During this time the number of publications that have been dedicated to protein aggregation has increased exponentially, tackling the problem from several different and sometime contradictory perspectives. This review is meant to summarize some of the highlights that come from these studies and introduce this topical issue on the subject. The factors that make a protein aggregate and the cellular strategies that defend from aggregation are discussed together with the perspectives that the accumulated knowledge may open.

  9. A Member of the Arabidopsis Mitochondrial Transcription Termination Factor Family Is Required for Maturation of Chloroplast Transfer RNAIle(GAU).

    PubMed

    Romani, Isidora; Manavski, Nikolay; Morosetti, Arianna; Tadini, Luca; Maier, Swetlana; Kühn, Kristina; Ruwe, Hannes; Schmitz-Linneweber, Christian; Wanner, Gerhard; Leister, Dario; Kleine, Tatjana

    2015-09-01

    Plastid gene expression is crucial for organelle function, but the factors that control it are still largely unclear. Members of the so-called mitochondrial transcription termination factor (mTERF) family are found in metazoans and plants and regulate organellar gene expression at different levels. Arabidopsis (Arabidopsis thaliana) mTERF6 is localized in chloroplasts and mitochondria, and its knockout perturbs plastid development and results in seedling lethality. In the leaky mterf6-1 mutant, a defect in photosynthesis is associated with reduced levels of photosystem subunits, although corresponding messenger RNA levels are unaffected, whereas translational capacity and maturation of chloroplast ribosomal RNAs (rRNAs) are perturbed in mterf6-1 mutants. Bacterial one-hybrid screening, electrophoretic mobility shift assays, and coimmunoprecipitation experiments reveal a specific interaction between mTERF6 and an RNA sequence in the chloroplast isoleucine transfer RNA gene (trnI.2) located in the rRNA operon. In vitro, recombinant mTERF6 bound to its plastid DNA target site can terminate transcription. At present, it is unclear whether disturbed rRNA maturation is a primary or secondary defect. However, it is clear that mTERF6 is required for the maturation of trnI.2. This points to an additional function of mTERFs. PMID:26152711

  10. Optimal policies for aggregate recycling from decommissioned forest roads.

    PubMed

    Thompson, Matthew; Sessions, John

    2008-08-01

    To mitigate the adverse environmental impact of forest roads, especially degradation of endangered salmonid habitat, many public and private land managers in the western United States are actively decommissioning roads where practical and affordable. Road decommissioning is associated with reduced long-term environmental impact. When decommissioning a road, it may be possible to recover some aggregate (crushed rock) from the road surface. Aggregate is used on many low volume forest roads to reduce wheel stresses transferred to the subgrade, reduce erosion, reduce maintenance costs, and improve driver comfort. Previous studies have demonstrated the potential for aggregate to be recovered and used elsewhere on the road network, at a reduced cost compared to purchasing aggregate from a quarry. This article investigates the potential for aggregate recycling to provide an economic incentive to decommission additional roads by reducing transport distance and aggregate procurement costs for other actively used roads. Decommissioning additional roads may, in turn, result in improved aquatic habitat. We present real-world examples of aggregate recycling and discuss the advantages of doing so. Further, we present mixed integer formulations to determine optimal levels of aggregate recycling under economic and environmental objectives. Tested on an example road network, incorporation of aggregate recycling demonstrates substantial cost-savings relative to a baseline scenario without recycling, increasing the likelihood of road decommissioning and reduced habitat degradation. We find that aggregate recycling can result in up to 24% in cost savings (economic objective) and up to 890% in additional length of roads decommissioned (environmental objective). PMID:18481140

  11. Optimal Policies for Aggregate Recycling from Decommissioned Forest Roads

    NASA Astrophysics Data System (ADS)

    Thompson, Matthew; Sessions, John

    2008-08-01

    To mitigate the adverse environmental impact of forest roads, especially degradation of endangered salmonid habitat, many public and private land managers in the western United States are actively decommissioning roads where practical and affordable. Road decommissioning is associated with reduced long-term environmental impact. When decommissioning a road, it may be possible to recover some aggregate (crushed rock) from the road surface. Aggregate is used on many low volume forest roads to reduce wheel stresses transferred to the subgrade, reduce erosion, reduce maintenance costs, and improve driver comfort. Previous studies have demonstrated the potential for aggregate to be recovered and used elsewhere on the road network, at a reduced cost compared to purchasing aggregate from a quarry. This article investigates the potential for aggregate recycling to provide an economic incentive to decommission additional roads by reducing transport distance and aggregate procurement costs for other actively used roads. Decommissioning additional roads may, in turn, result in improved aquatic habitat. We present real-world examples of aggregate recycling and discuss the advantages of doing so. Further, we present mixed integer formulations to determine optimal levels of aggregate recycling under economic and environmental objectives. Tested on an example road network, incorporation of aggregate recycling demonstrates substantial cost-savings relative to a baseline scenario without recycling, increasing the likelihood of road decommissioning and reduced habitat degradation. We find that aggregate recycling can result in up to 24% in cost savings (economic objective) and up to 890% in additional length of roads decommissioned (environmental objective).

  12. A potential screening factor for accumulation of cholesteyl ester transfer protein deficiency in East Asia: Schistosoma japonicum.

    PubMed

    Yokoyama, Shinji

    2014-04-01

    Cholesteryl ester transfer protein (CETP)-deficiency manifests a unique plasma lipoprotein profile without other apparent symptoms. It is highly common in East Asia while rather rare anywhere else. A potential environmental screening factor(s) may therefore contribute to this eccentric distribution, such as its selective advantage against a regional illness, most likely an infectious disease, in relation to plasma lipoproteins. Blood flukes use the host plasma lipoproteins as nutrient sources through the lipoprotein receptor-like systems. Its Asian-specific species, Schistosoma (S) japonicum, which has been endemic in East Asia, takes up cholesteryl ester (CE) from high-density lipoprotein (HDL) for the embryonation of their eggs to miracidia, a critical step of the hepatic pathogenesis of this parasite, but poorly from HDL of CETP-deficiency. CD36-related protein (CD36RP) was cloned from the adults and the eggs of S. japonicum, with 1880-bp encoding 506 amino-acid residues exhibiting the CD36 domains and two transmembrane regions. Its extracellular domain selectively bound human HDL but neither LDL nor CETP-deficiency HDL, and the antibody against the extracellular domain suppressed the selective HDL-CE uptake and embryonation of the eggs. When infected with S. japonicum, wild-type mice developed less hepatic granulomatosis than CETP-transgenic mice by the ectopic egg embryonation. CD36RP is thus a candidate receptor of S. japonicum to facilitate uptake of HDL-CE necessary for egg embryonation. Abnormal HDL caused by CETP-deficiency retards this process and thereby protects the patients from development of hepatic lesions. S. japonicum infection is a potential screening factor for high prevalence of CETP deficiency in East Asia. PMID:24388961

  13. Plasmid-based transient human stromal cell-derived factor-1 gene transfer improves cardiac function in chronic heart failure

    PubMed Central

    Sundararaman, S; Miller, T J; Pastore, J M; Kiedrowski, M; Aras, R; Penn, M S

    2011-01-01

    We previously demonstrated that transient stromal cell-derived factor-1 alpha (SDF-1) improved cardiac function when delivered via cell therapy in ischemic cardiomyopathy at a time remote from acute myocardial infarction (MI) rats. We hypothesized that non-viral gene transfer of naked plasmid DNA-expressing hSDF-1 could similarly improve cardiac function. To optimize plasmid delivery, we tested SDF-1 and luciferase plasmids driven by the cytomegalovirus (CMV) promoter with (pCMVe) or without (pCMV) translational enhancers or α myosin heavy chain (pMHC) promoter in a rodent model of heart failure. In vivo expression of pCMVe was 10-fold greater than pCMV and pMHC expression and continued over 30 days. We directly injected rat hearts with SDF-1 plasmid 1 month after MI and assessed heart function. At 4 weeks after plasmid injection, we observed a 35.97 and 32.65% decline in fractional shortening (FS) in control (saline) animals and pMHC-hSDF1 animals, respectively, which was sustained to 8 weeks. In contrast, we observed a significant 24.97% increase in animals injected with the pCMVe-hSDF1 vector. Immunohistochemistry of cardiac tissue revealed a significant increase in vessel density in the hSDF-1-treated animals compared with control animals. Increasing SDF-1 expression promoted angiogenesis and improved cardiac function in rats with ischemic heart failure along with evidence of scar remodeling with a trend toward decreased myocardial fibrosis. These data demonstrate that stand-alone non-viral hSDF-1 gene transfer is a strategy for improving cardiac function in ischemic cardiomyopathy. PMID:21472007

  14. Inadequate passive immune transfer in puppies: definition, risk factors and prevention in a large multi-breed kennel.

    PubMed

    Mila, H; Feugier, A; Grellet, A; Anne, J; Gonnier, M; Martin, M; Rossig, L; Chastant-Maillard, S

    2014-09-01

    The prevalence of neonatal mortality is high in the canine species and far from well-studied. In most domestic neonates, an appropriate colostrum intake is a key element of the control of neonatal mortality. The aim of this study was to evaluate the impact of passive immune transfer on puppy mortality, assessed through serum immunoglobulin G (IgG) concentration at 2 days of age. Factors impacting passive immune transfer and the value of an oral immunoglobulin supplementation to prevent it were also analyzed. A total of 149 puppies from 34 litters (12 breeds) within one breeding kennel were included. Blood samples were collected at 2 days of age and colostrum was collected from their dams 1 day after whelping to assay IgG concentration. Puppies were weighed at birth and at 2 days of age for calculation of growth rate. Mortality was recorded until 3 weeks of age. Seventy randomly assigned puppies were orally supplemented with hyper-immunized adult plasma twice within the first 8h of life. IgG concentration at 2 days of age was significantly correlated with weight gain during the first 2 days of life. The multivariable model with litter as a random effect demonstrated that neonatal mortality was not influenced by breed size, sex, supplementation, litter size, nor colostrum IgG concentration, but by puppy IgG concentration at 2 days of age. According to the ROC curve, the minimal IgG concentration at and below which puppies were at higher risk of death was determined at 230 mg/dl. Puppy IgG concentration was significantly associated with growth rate, but not with breed size, sex, supplementation, litter size or colostrum IgG concentration in a multivariable model with litter as a random effect. This study demonstrates that neonatal mortality in puppies is related to the quality of passive immune transfer. The oral supplementation with hyper-immunized canine plasma neither decreased risk of mortality, nor improved serum IgG concentration at 2 days of age in puppies

  15. Automatic analysis of microscopic images of red blood cell aggregates

    NASA Astrophysics Data System (ADS)

    Menichini, Pablo A.; Larese, Mónica G.; Riquelme, Bibiana D.

    2015-06-01

    Red blood cell aggregation is one of the most important factors in blood viscosity at stasis or at very low rates of flow. The basic structure of aggregates is a linear array of cell commonly termed as rouleaux. Enhanced or abnormal aggregation is seen in clinical conditions, such as diabetes and hypertension, producing alterations in the microcirculation, some of which can be analyzed through the characterization of aggregated cells. Frequently, image processing and analysis for the characterization of RBC aggregation were done manually or semi-automatically using interactive tools. We propose a system that processes images of RBC aggregation and automatically obtains the characterization and quantification of the different types of RBC aggregates. Present technique could be interesting to perform the adaptation as a routine used in hemorheological and Clinical Biochemistry Laboratories because this automatic method is rapid, efficient and economical, and at the same time independent of the user performing the analysis (repeatability of the analysis).

  16. Aggregate Remote Memory Copy Interface

    2006-02-23

    The purpose of the Aggregate Remote Memory Copy (ARMCI) library is to provide a general- purpose, efficient, and Widely portable remote memory access (RMA) operations (one-sided communication) optimized for Contiguous and noncontiguous (strided, scatter/gather, I/O vector) data transfers. In addition, ARMCI includes a set of atomic and mutual exclusion operations. The development ARMCI is driven by the need to support the global-addres space communication model in context of distributed regular or irregular distributed data structures,more » communication libraries, and compilers. ARMCI is a standalone system that could be used to support user-level libraries and applications that use MPI or PVM.« less

  17. Charge form factor of the neutron at low momentum transfer from the 2H-->(e-->,e'n)1H reaction.

    PubMed

    Geis, E; Kohl, M; Ziskin, V; Akdogan, T; Arenhövel, H; Alarcon, R; Bertozzi, W; Booth, E; Botto, T; Calarco, J; Clasie, B; Crawford, C B; DeGrush, A; Donnelly, T W; Dow, K; Farkhondeh, M; Fatemi, R; Filoti, O; Franklin, W; Gao, H; Gilad, S; Hasell, D; Karpius, P; Kolster, H; Lee, T; Maschinot, A; Matthews, J; McIlhany, K; Meitanis, N; Milner, R G; Rapaport, J; Redwine, R P; Seely, J; Shinozaki, A; Sirca, S; Sindile, A; Six, E; Smith, T; Steadman, M; Tonguc, B; Tschalaer, C; Tsentalovich, E; Turchinetz, W; Xiao, Y; Xu, W; Zhang, C; Zhou, Z; Zwart, T

    2008-07-25

    We report new measurements of the neutron charge form factor at low momentum transfer using quasielastic electrodisintegration of the deuteron. Longitudinally polarized electrons at an energy of 850 MeV were scattered from an isotopically pure, highly polarized deuterium gas target. The scattered electrons and coincident neutrons were measured by the Bates Large Acceptance Spectrometer Toroid (BLAST) detector. The neutron form factor ratio GEn/GMn was extracted from the beam-target vector asymmetry AedV at four-momentum transfers Q2=0.14, 0.20, 0.29, and 0.42 (GeV/c)2. PMID:18764321

  18. Crushed aggregates for roads and their properties for frost protection

    NASA Astrophysics Data System (ADS)

    Kuznetsova, Elena; Willy Danielsen, Svein

    2015-04-01

    of the road system. According to new specification; the size of large stones for this layer should be maximum 0.5 m (longest edge) or ½ layer thickness. And minimum 30% of stones should be less than 90 mm. Fines content (<0.063 mm) should be maximum 15% of the material less than 22.4 mm. Analysing these new requirements, several questions are arising. First of all how this materials size will affect heat exchange in the layer, secondly - if the allowable fines content will make the materials frost susceptible. For calculations of frost protection layer thickness the knowledge of thermal conductivity of the aggregate layers is required. Handbook for geotechnical investigations of the soils provides this data for natural gravel which is limited by 0.7 - 1.3 W/mK. But when it comes to the crushed rocks, it can be significantly increased due to the higher conductivity of minerals (especially if they contain high amount of quartz), as well as due to higher effective conductivity. In rock-fill materials, i.e. materials with large particles and low degree of saturation, convection and radiation are the predominant heat transfer mechanisms. Convection and radiation can increase the effective conductivity by factor 2-10. Lebeau and Konrad (2007) showed that convection heat transfer could lead to the formation of undesirable permafrost conditions in toe drains of embankment dams located in Northern Quebec, i.e. in areas where there are no naturally occurring permafrost soils. In a frost design method the required parameter values of crushed rock aggregates are thermal conductivity, density and water content. The heat transfer during the freezing of natural soils is assumed proportional to thermal conductivity of the material. In a coarse-grained material with abundant pore space, convective heat transfer and radiation may be a considerable factor, sometimes even more significant than conduction. Specifications used by pavement engineers in most countries are solely based on

  19. Transfer factor of the radionuclides in food crops from high-background radiation area of south west India.

    PubMed

    Shanthi, G; Thanka Kumaran, J Thampi; Gnana Raj, G Allen; Maniyan, C G

    2012-04-01

    It is necessary to obtain the transfer factor (TF) of long-lived radionuclides because soil type and vegetation can affect TF. We studied the food crops commonly consumed by the general public of Kanyakumari district of south India. The main focus was on rice, fruits, vegetables and tapioca because the consumption of these is high. The soil to rice TF for the radionuclides, (226)Ra, (232)Th, (238)U and (40) K are 8.8×10(-2), 14.2×10(-2), 5.8×10(-2) and 6.3×10(-2), respectively. The TF of tapioca for (226)Ra, (232)Th, (238)U and (40) K are 6.2×10(-2) , 11×10(-2), 1.9×10(-2) and 8.9×10(-2), respectively. For fruits and vegetables, the TFs are low. In the majority of the crops the non-edible parts accumulate more radionuclides than the edible parts. PMID:21680604

  20. BASELINE PARAMETER UPDATE FOR HUMAN HEALTH INPUT AND TRANSFER FACTORS FOR RADIOLOGICAL PERFORMANCE ASSESSMENTS AT THE SAVANNAH RIVER SITE

    SciTech Connect

    Coffield, T; Patricia Lee, P

    2007-01-31

    The purpose of this report is to update parameters utilized in Human Health Exposure calculations and Bioaccumulation Transfer Factors utilized at SRS for Performance Assessment modeling. The reason for the update is to utilize more recent information issued, validate information currently used and correct minor inconsistencies between modeling efforts performed in SRS contiguous areas of the heavy industrialized central site usage areas called the General Separations Area (GSA). SRS parameters utilized were compared to a number of other DOE facilities and generic national/global references to establish relevance of the parameters selected and/or verify the regional differences of the southeast USA. The parameters selected were specifically chosen to be expected values along with identifying a range for these values versus the overly conservative specification of parameters for estimating an annual dose to the maximum exposed individual (MEI). The end uses are to establish a standardized source for these parameters that is up to date with existing data and maintain it via review of any future issued national references to evaluate the need for changes as new information is released. These reviews are to be added to this document by revision.

  1. Soil-to-root vegetable transfer factors for (226)Ra, (232)Th, (40)K, and (88)Y in Malaysia.

    PubMed

    Asaduzzaman, Kh; Khandaker, Mayeen Uddin; Amin, Y M; Bradley, D A; Mahat, R H; Nor, R M

    2014-09-01

    Soil-to-plant transfer factors (TFs) are of fundamental importance in assessing the environmental impact due to the presence of radioactivity in soil and agricultural crops. Tapioca and sweet potato, both root crops, are popular foodstuffs for a significant fraction of the Malaysian population, and result in intake of radionuclides. For the natural field conditions experienced in production of these foodstuffs, TFs and the annual effective dose were evaluated for the natural radionuclides (226)Ra, (232)Th, (40)K, and for the anthropogenic radionuclide (88)Y, the latter being a component of fallout. An experimental tapioca field was developed for study of the time dependence of plant uptake. For soil samples from all study locations other than the experimental field, it has been shown that these contain the artificial radionuclide (88)Y, although the uptake of (88)Y has only been observed in the roots of the plant Manihot esculenta (from which tapioca is derived) grown in mining soil. The estimated TFs for (226)Ra and (232)Th for tapioca and sweet potato are very much higher than that reported by the IAEA. For all study areas, the annual effective dose from ingestion of tapioca and sweet potato are estimated to be lower than the world average (290 μSv y(-1)). PMID:24814722

  2. Development of a Cell-Based Fluorescence Resonance Energy Transfer Reporter for Bacillus anthracis Lethal Factor Protease

    SciTech Connect

    Kimura, R H; Steenblock, E R; Camarero, J A

    2007-03-22

    We report the construction of a cell-based fluorescent reporter for anthrax lethal factor (LF) protease activity using the principle of fluorescence resonance energy transfer (FRET). This was accomplished by engineering an Escherichia coli cell line to express a genetically encoded FRET reporter and LF protease. Both proteins were encoded in two different expression plasmids under the control of different tightly controlled inducible promoters. The FRET-based reporter was designed to contain a LF recognition sequence flanked by the FRET pair formed by CyPet and YPet fluorescent proteins. The length of the linker between both fluorescent proteins was optimized using a flexible peptide linker containing several Gly-Gly-Ser repeats. Our results indicate that this FRET-based LF reporter was readily expressed in E. coli cells showing high levels of FRET in vivo in the absence of LF. The FRET signal, however, decreased 5 times after inducing LF expression in the same cell. These results suggest that this cell-based LF FRET reporter may be used to screen genetically encoded libraries in vivo against LF.

  3. Technology meets aggregate

    SciTech Connect

    Wilson, C.; Swan, C.

    2007-07-01

    New technology carried out at Tufts University and the University of Massachusetts on synthetic lightweight aggregate has created material from various qualities of fly ash from coal-fired power plants for use in different engineered applications. In pilot scale manufacturing tests an 'SLA' containing 80% fly ash and 20% mixed plastic waste from packaging was produced by 'dry blending' mixed plastic with high carbon fly ash. A trial run was completed to produce concrete masonry unit (CMU) blocks at a full-scale facility. It has been shown that SLA can be used as a partial substitution of a traditional stone aggregate in hot asphalt mix. 1 fig., 2 photos.

  4. The cell aggregating propensity of probiotic actinobacterial isolates: isolation and characterization of the aggregation inducing peptide pheromone.

    PubMed

    Muthu Selvam, Ramu; Vinothini, Gopal; Palliyarai Thaiyammal, Sethuramalingam; Latha, Selvanathan; Chinnathambi, Arunachalam; Dhanasekaran, Dharumadurai; Padmanabhan, Parasuraman; Ali Alharbi, Sulaiman; Archunan, Govindaraju

    2016-01-01

    The auto-aggregating ability of a probiotic is a prerequisite for colonization and protection of the gastrointestinal tract, whereas co-aggregation provides a close interaction with pathogenic bacteria. Peptide pheromone mediated signaling has been studied in several systems. However, it has not yet been explored in prokaryotes, especially actinobacteria. Hence, in the present study, the diffusible aggregation promoting factor was purified from the culture supernatant of a potent actinobacterial probiont and characterized using 20 different actinobacterial cultures isolated from the gut region of chicken and goat. The results showed that the pheromone-like compound induces the aggregation propensity of treated isolates. The factor was found to be a heat stable, acidic pH resistant, low molecular weight peptide which enhances the biofilm forming ability of other actinobacterial isolates. The aggregation promoting factor represents a bacterial sex factor (pheromone) and its characterization confirms its usage in the probiotic formulation. PMID:26754920

  5. Soil to rice transfer factors for (226)Ra, (228)Ra, (210)Pb, (40)K and (137)Cs: a study on rice grown in India.

    PubMed

    Karunakara, N; Rao, Chetan; Ujwal, P; Yashodhara, I; Kumara, Sudeep; Ravi, P M

    2013-04-01

    India is the second largest producer of rice (Oryza sativa L.) in the world and rice is an essential component of the diet for a majority of the population in India. However, detailed studies aimed at the evaluation of radionuclide transfer factors (F(v)) for the rice grown in India are almost non-existent. This paper presents the soil to rice transfer factors for natural ((226)Ra, (228)Ra, (40)K, and (210)Pb) and artificial ((137)Cs) radionuclides for rice grown in natural field conditions on the West Coast of India. A rice field was developed very close to the Kaiga nuclear power plant and the water required for this field was drawn from the cooling water discharge canal of the power plant. For a comparative study of the radionuclide transfer factors, rice samples were also collected from the rice fields of nearby villages. The study showed that the (226)Ra and (228)Ra activity concentrations were below detection levels in different organs of the rice plant. The soil to un-hulled rice grain (40)K transfer factor varied in the range of 6.5 × 10(-1) to 2.9 with a mean of 0.15 × 10(1), and of (210)Pb varied in the range of <1.2 × 10(-2) to 8.1 × 10(-1) with a mean of 1.4 × 10(-1), and of (137)Cs varied in the range of 6.6 × 10(-2) to 3.4 × 10(-1) with a mean of 2.1 × 10(-1). The mean values of un-hulled grain to white rice processing retention factors (F(r)) were 0.12 for (40)K, 0.03 for (210)Pb, and 0.14 for (137)Cs. Using these processing retention factors, the soil to white rice transfer factors were estimated and these were found to have mean values of 1.8 × 10(-1), 4.2 × 10(-3), and 3.0 × 10(-2) for (40)K, (210)Pb, and (137)Cs, respectively. The study has shown that the transfer of (40)K was higher for above the ground organs than for the root, but (210)Pb and (137)Cs were retained in the root and their transfer to above the ground organs of the rice plant is significantly lower. PMID:23266913

  6. Aggregates, broccoli and cauliflower

    NASA Astrophysics Data System (ADS)

    Grey, Francois; Kjems, Jørgen K.

    1989-09-01

    Naturally grown structures with fractal characters like broccoli and cauliflower are discussed and compared with DLA-type aggregates. It is suggested that the branching density can be used to characterize the growth process and an experimental method to determine this parameter is proposed.

  7. Evaluation of red blood cell aggregation in diabetes by computerized image analysis.

    PubMed

    Foresto, P; D'Arrigo, M; Carreras, L; Cuezzo, R E; Valverde, J; Rasia, R

    2000-01-01

    Red blood cell (RBC) aggregation has been widely studied and its importance is well established in the rheology of microcirculation. RBC aggregation is a major factor responsible for the flow properties of blood. Increased RBC aggregation has been observed in several pathological states. Therefore, the measurement of erythrocyte aggregation is rheologically important for quantifying flow abnormality in pathological conditions. Normal RBC under low flow or at rest form rouleaux aggregates, while abnormal RBC aggregation may lead to the formation of irregular aggregate structures, which may be induced by cell-associated factors (reduced membrane sialic acid levels) but also by extracellular factors. The main objective of the present investigation was to study RBC aggregate morphology in diabetic patients, using direct microscopic observation and numerical processing of recorded digitized images. Blood samples were obtained from 20 diabetic patients and from 15 normal control subjects. The aggregate morphology was quantified by the so-called Aggregate Shape Parameter (ASP) defined as the ratio of the aggregate projected area to its square perimeter. ASP appeared significantly higher (p < 10(-5)) in diabetic patients (0.65 +/- 0.18) than in normal controls (0.28 +/- 0.15). This rheo-optical method based on the theoretical model for rouleaux aggregates provides a useful reference for measuring deviations of RBC aggregate morphology. Increased aggregation of RBC resulting from a decreased sialylation of glycophorins may be an important factor in the development of vascular diseases and in the microcirculation impairment. PMID:11188894

  8. Metaconcrete: Engineered aggregates for enhanced dynamic performance

    NASA Astrophysics Data System (ADS)

    Mitchell, Stephanie J.

    This work presents the development and investigation of a new type of concrete for the attenuation of waves induced by dynamic excitation. Recent progress in the field of metamaterials science has led to a range of novel composites which display unusual properties when interacting with electromagnetic, acoustic, and elastic waves. A new structural metamaterial with enhanced properties for dynamic loading applications is presented, which is named metaconcrete. In this new composite material the standard stone and gravel aggregates of regular concrete are replaced with spherical engineered inclusions. Each metaconcrete aggregate has a layered structure, consisting of a heavy core and a thin compliant outer coating. This structure allows for resonance at or near the eigenfrequencies of the inclusions, and the aggregates can be tuned so that resonant oscillations will be activated by particular frequencies of an applied dynamic loading. The activation of resonance within the aggregates causes the overall system to exhibit negative effective mass, which leads to attenuation of the applied wave motion. To investigate the behavior of metaconcrete slabs under a variety of different loading conditions a finite element slab model containing a periodic array of aggregates is utilized. The frequency dependent nature of metaconcrete is investigated by considering the transmission of wave energy through a slab, which indicates the presence of large attenuation bands near the resonant frequencies of the aggregates. Applying a blast wave loading to both an elastic slab and a slab model that incorporates the fracture characteristics of the mortar matrix reveals that a significant portion of the supplied energy can be absorbed by aggregates which are activated by the chosen blast wave profile. The transfer of energy from the mortar matrix to the metaconcrete aggregates leads to a significant reduction in the maximum longitudinal stress, greatly improving the ability of the material

  9. Numerical Investigation of Heat Transfer and Friction Factor Characteristics in a Circular Tube Fitted with V-Cut Twisted Tape Inserts

    PubMed Central

    Salman, Sami D.; Kadhum, Abdul Amir H.; Takriff, Mohd S.; Mohamad, Abu Bakar

    2013-01-01

    Numerical investigation of the heat transfer and friction factor characteristics of a circular fitted with V-cut twisted tape (VCT) insert with twist ratio (y = 2.93) and different cut depths (w = 0.5, 1, and 1.5 cm) were studied for laminar flow using CFD package (FLUENT-6.3.26). The data obtained from plain tube were verified with the literature correlation to ensure the validation of simulation results. Classical twisted tape (CTT) with different twist ratios (y = 2.93, 3.91, 4.89) were also studied for comparison. The results show that the enhancement of heat transfer rate induced by the classical and V-cut twisted tape inserts increases with the Reynolds number and decreases with twist ratio. The results also revealed that the V-cut twisted tape with twist ratio y = 2.93 and cut depth w = 0.5 cm offered higher heat transfer rate with significant increases in friction factor than other tapes. In addition the results of V-cut twist tape compared with experimental and simulated data of right-left helical tape inserts (RLT), it is found that the V-cut twist tape offered better thermal contact between the surface and the fluid which ultimately leads to a high heat transfer coefficient. Consequently, 107% of maximum heat transfer was obtained by using this configuration. PMID:24078795

  10. An Exploratory Examination of Organizational Factors Leading to Transfer of Hispanic Students: A Case Study. ASHE Annual Meeting Paper.

    ERIC Educational Resources Information Center

    Laden, Berta Vigil

    Hispanics are the fastest growing ethnic group nationally, yet they continue to be undereducated and underemployed. This paper discusses one community college's success in preparing and transfering Hispanic students to 4-year institutions. The study examined a San Francisco Bay Area high transfer community college, which was experiencing an…

  11. In-Hospital Mortality among Rural Medicare Patients with Acute Myocardial Infarction: The Influence of Demographics, Transfer, and Health Factors

    ERIC Educational Resources Information Center

    Muus, Kyle J.; Knudson, Alana D.; Klug, Marilyn G.; Wynne, Joshua

    2011-01-01

    Context/Purpose: Most rural hospitals can provide medical care to acute myocardial infarction (AMI) patients, but a need for advanced cardiac care requires timely transfer to a tertiary hospital. There is little information on AMI in-hospital mortality predictors among rural transfer patients. Methods: Cross-sectional retrospective analyses on…

  12. Expression of human factor IX in rabbit hepatocytes by retrovirus-mediated gene transfer: Potential for gene therapy of hemophilia B

    SciTech Connect

    Thompson, A.R. Puget Sound Blood Center, Seattle, WA ); Darlington, G. ); Armentano, D.; Woo, S.L.C.

    1990-08-01

    Hemophilia B (Christmas disease) is a chromosome X-linked blood clotting disorder which results when factor IX is deficient or functionally defective. The enzyme is synthesized in the liver, and the existence of animal models for this genetic disease will permit the development of somatic gene therapy protocols aimed at transfer of the functional gene into the liver. The authors report the construction of an N2-based recombinant retroviral vector, NCMVFIX, for efficient transfer and expression of human factor IX cDNA in primary rabbit hepatocytes. In this construct the human cytomegalovirus immediate early promoter directs the expression of factor IX. Hepatocytes were isolated from 3-week-old New Zealand White rabbits, infected with the recombinant virus, and analyzed for secretion of active factor IX. The infected rabbit hepatocytes produced human factor IX that is indistinguishable from enzyme derived from normal human plasma. The recombinant protein is sufficiently {gamma}-carboxylated and is functionally active in clotting assays. These results establish the feasibility of using infected hepatocytes for the expression of this protein and are a step toward the goal of correcting hemophilia B by hepatic gene transfer.

  13. 137Cs Inter-Plant Concentration Ratios Provide a Predictive Tool for Coral Atolls with Distinct Benefits Over Transfer Factors

    SciTech Connect

    Robison, W L; Hamilton, T F; Bogen, K; Corado, C L; Kehl, S R

    2007-07-17

    Inter-plant concentration ratios (IPCR), [Bq g{sup -1} {sup 137}Cs in coral atoll tree food-crops/Bq g{sup -1} {sup 137}Cs in leaves of native plant species whose roots share a common soil volume], can replace transfer factors (TF) to predict {sup 137}Cs concentration in tree food-crops in a contaminated area with an aged source term. The IPCR strategy has significant benefits relative to TF strategy for such purposes in the atoll ecosystem. IPCR strategy applied to specific assessments takes advantage of the fact tree roots naturally integrate 137Cs over large volumes of soil. Root absorption of {sup 137}Cs replaces large-scale, expensive soil sampling schemes to reduce variability in {sup 137}Cs concentration due to inhomogeneous radionuclide distribution. IPCR [drinking-coconut meat (DCM)/Scaevola (SCA) and Tournefortia (TOU) leaves (native trees growing on all atoll islands)] are log normally distributed (LND) with geometric standard deviation (GSD) = 1.85. TF for DCM from Enewetak, Eneu, Rongelap and Bikini Atolls are LND with GSD's of 3.5, 3.0, 2.7, and 2.1, respectively. TF GSD for Rongelap copra coconut meat is 2.5. IPCR of Pandanus fruit to SCA and TOU leaves are LND with GSD = 1.7 while TF GSD is 2.1. Because IPCR variability is much lower than TF variability, relative sampling error of an IPCR field sample mean is up 6- to 10-fold lower than that of a TF sample mean if sample sizes are small (10 to 20). Other IPCR advantages are that plant leaf samples are collected and processed in far less time with much less effort and cost than soil samples.

  14. Lung Transfer Factor in Middle Aged Asymptomatic Male Smokers of a City from West India: A Cross-Sectional Study

    PubMed Central

    Gadhavi, Bhakti P.; Mehta, Hemant B.; Shah, Chinmay J.; Gokhale, Pradnya A.; Makwana, Amit H.

    2016-01-01

    Introduction Smoking is an increasingly popular indulgence in India. Assessment by routine spirometry falls short of direct functional parameter like Diffusion Lung Capacity (DLC), also known as lung transfer factor (LTF). Aim To measure LTF amongst middle aged male smokers and to study various correlates for it. Materials and Methods Total of 45 asymptomatic male current smokers were enrolled for this cross-sectional study conducted at pulmonary function testing lab of Physiology Department of our college. Smoking history was evaluated and smoking index was defined by product of number smoked per day and years smoked. We used instrument Ultima PFX of Medgraphic Company. After pre syringe calibration LTF was measured by Methane mixture using protocols of ATS. Parameters measured were Dlco-uncorrected, corrected and normalized to VA (alveolar volume). Results were compared for statistical significance and significance was set as p <0.05. Results In case group of 45(25 bidi and 20 cigarette smokers) mean age was 30 years, mean duration was 8 years, mean smoking index was 60. We found small insignificant decline in actual LTF values than predicted which was not significantly different between bidi and cigarette smokers. Duration, age and intensity of smoking were negatively and significantly correlated with LTF value while anthropometric parameters were not. Conclusion Smoking adversely affects LTF in young asymptomatic current male smoker that further declines with severity of smoking and with duration regardless of type of smoking. With years to come, these alterations can largely be prevented by smoking cessation, at least theoretically. PMID:27134864

  15. (137)Cs inter-plant concentration ratios provide a predictive tool for coral atolls with distinct benefits over transfer factors.

    PubMed

    Robison, William L; Hamilton, Terry F; Bogen, Kenneth T; Conrado, Cynthia L; Kehl, Steven R

    2008-01-01

    Inter-plant concentration ratios (IPCR) [Bqg(-1)(137)Cs in coral atoll tree food crops/Bqg(-1)(137)Cs in leaves of native plant species whose roots share a common soil volume] can replace transfer factors (TF) to predict (137)Cs concentration in tree food crops in a contaminated area with an aged source term. The IPCR strategy has significant benefits relative to TF strategy for such purposes in the atoll ecosystem. IPCR strategy applied to specific assessments takes advantage of the fact that tree roots naturally integrate (137)Cs over large volumes of soil. Root absorption of (137)Cs replaces large-scale, expensive soil sampling schemes to reduce variability in (137)Cs concentration due to inhomogeneous radionuclide distribution. IPCR [drinking-coconut meat (DCM)/Scaevola (SCA) and Tournefortia (TOU) leaves (native trees growing on all atoll islands)] are log-normally distributed (LND) with geometric standard deviation (GSD)=1.85. TF for DCM from Enewetak, Eneu, Rongelap and Bikini Atolls are LND with GSDs of 3.5, 3.0, 2.7, and 2.1, respectively. TF GSD for Rongelap copra coconut meat is 2.5. IPCR of Pandanus fruit to SCA and TOU leaves are LND with GSD=1.7 while TF GSD is 2.1. Because IPCR variability is much lower than TF variability, relative sampling error of an IPCR field sample mean is up 6- to 10-fold lower than that of a TF sample mean if sample sizes are small (10-20). Other IPCR advantages are that plant leaf samples are collected and processed in far less time with much less effort and cost than soil samples. PMID:17904254

  16. Soil-to-Crop Transfer Factors of Naturally Occurring Radionuclides and Stable Elements for Long-Term Dose Assessment

    SciTech Connect

    Uchida, S.; Tagami, K.

    2007-07-01

    A soil-to-crop transfer factor, TF, is a key parameter that directly affects the internal dose assessment for the ingestion pathway, however, obtaining TFs of various long-lived radionuclides occurred during operation of nuclear power plants is difficult because most of them could not be found in natural environments. In this study, therefore, we collected crops and their associated soils throughout Japan and measured more than 50 elements to obtain TFs under equilibrium conditions. The TFs were calculated for 42 elements (Li, Na, Mg, Al, Si, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Y, Mo, Cd, Sn, I, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tl, Pb, Th and U) from their concentrations in both crop and soil samples. The TF is defined as the concentration of an isotope in a crop (in Bq/kg or mg/kg dry weight) divided by the concentration of the isotope in soil (in Bq.kg or mg/kg dry weight). Probability distributions of TFs for 62 upland field crops were usually log-normal type so that geometric means (GMs) were calculated. The values for the elements of interest from the viewpoint of long-term dose assessment were 2.5E-02 for Se, 7.9E-02 for Sr, 3.1E-03 for Cs, 4.2E-04 for Th and 4.6E-04 for U. Leafy vegetable showed the highest TFs for all the elements among the crop groups. It was clear that these data were usually within the 95% confidence limits of TFs compiled by IAEA in Technical Report Series 364. (authors)

  17. Bioavailability and soil-to-plant transfer factors as indicators of potentially toxic element contamination in agricultural soils.

    PubMed

    Adamo, Paola; Iavazzo, Pietro; Albanese, Stefano; Agrelli, Diana; De Vivo, Benedetto; Lima, Annamaria

    2014-12-01

    Soil pollution in agricultural lands poses a serious threat to food safety, and suggests the need for consolidated methods providing advisory indications for soil management and crop production. In this work, the three-step extraction procedure developed by the EU Measurement and Testing Programme and two soil-to-plant transfer factors (relative to total and bioavailable concentration of elements in soil) were applied on polluted agricultural soils from southern Italy to obtain information on the retention mechanisms of metals in soils and on their level of translocation to edible vegetables. The study was carried out in the Sarno river plain of Campania, an area affected by severe environmental degradation potentially impacting the health of those consuming locally produced vegetables. Soil samples were collected in 36 locations along the two main rivers flowing into the plain. In 11 sites, lettuce plants were collected at the normal stage of consumption. According to Italian environmental law governing residential soils, and on the basis of soil background reference values for the study area, we found diffuse pollution by Be, Sn and Tl, of geogenic origin, Cr and Cu from anthropogenic sources such as tanneries and intensive agriculture, and more limited pollution by Pb, Zn and V. It was found that metals polluting soils as a result of human activities were mainly associated to residual, oxidizable and reducible phases, relatively immobile and only potentially bioavailable to plants. By contrast, the essential elements Zn and Cu showed a tendency to become more readily mobile and bioavailable as their total content in soil increased and were more easily transported to the edible parts of lettuce than other pollutants. According to our results, current soil pollution in the studied area does not affect the proportion of metals taken up by lettuce plants and there is a limited health risk incurred. PMID:25217740

  18. Molecular Cloning of a Xylosyltransferase That Transfers the Second Xylose to O-Glucosylated Epidermal Growth Factor Repeats of Notch*

    PubMed Central

    Sethi, Maya K.; Buettner, Falk F. R.; Ashikov, Angel; Krylov, Vadim B.; Takeuchi, Hideyuki; Nifantiev, Nikolay E.; Haltiwanger, Robert S.; Gerardy-Schahn, Rita; Bakker, Hans

    2012-01-01

    The extracellular domain of Notch contains epidermal growth factor (EGF) repeats that are extensively modified with different O-linked glycans. O-Fucosylation is essential for receptor function, and elongation with N-acetylglucosamine, catalyzed by members of the Fringe family, modulates Notch activity. Only recently, genes encoding enzymes involved in the O-glucosylation pathway have been cloned. In the Drosophila mutant rumi, characterized by a mutation in the protein O-glucosyltransferase, Notch signaling is impaired in a temperature-dependent manner, and a mouse knock-out leads to embryonic lethality. We have previously identified two human genes, GXYLT1 and GXYLT2, encoding glucoside xylosyltransferases responsible for the transfer of xylose to O-linked glucose. The identity of the enzyme further elongating the glycan to generate the final trisaccharide xylose-xylose-glucose, however, remained unknown. Here, we describe that the human gene C3ORF21 encodes a UDP-xylose:α-xyloside α1,3-xylosyltransferase, acting on xylose-α1,3-glucoseβ1-containing acceptor structures. We have, therefore, renamed it XXYLT1 (xyloside xylosyltransferase 1). XXYLT1 cannot act on a synthetic acceptor containing an α-linked xylose alone, but requires the presence of the underlying glucose. Activity on Notch EGF repeats was proven by in vitro xylosylation of a mouse Notch1 fragment recombinantly produced in Sf9 insect cells, a bacterially expressed EGF repeat from mouse Notch2 modified in vitro by Rumi and Gxylt2 and in vivo by co-expression of the enzyme with the Notch1 fragment. The enzyme was shown to be a typical type II membrane-bound glycosyltransferase localized in the endoplasmic reticulum. PMID:22117070

  19. Transfer factor of (90)Sr and (137)Cs to lettuce and winter wheat at different growth stage applications.

    PubMed

    Al Attar, Lina; Al-Oudat, Mohammad; Safia, Bassam; Ghani, Basem Abdul

    2015-12-01

    The effect of clay soil contamination time on the transfer factors (Fvs) of (137)Cs and (90)Sr was investigated in four different growth stages of winter wheat and lettuce crops. The experiment was performed in an open field using lysimeters. The Fvs were the ratio of the activity concentrations of the radionuclides in crops to those in soil, both as dry weight (Bq kg(-1)). Significant difference of log-Fvs was evaluated using one-way Analysis of Variance (ANOVA). Basically, Fvs of (90)Sr were higher than those of (137)Cs, despite of the application stage or crop' variety. Higher Fvs for both radionuclides were observed for lettuce in comparison to winter wheat. Fvs of (90)Sr showed comparable trends for both crops with enhanced Fvs obtained when contamination occurred in early stages, i.e. 1.20 for lettuce and 0.88 and 0.02 for winter wheat, straw and grains, respectively. Despite the fluctuation noted in the pattern of Fvs for (137)Cs, soil contaminated at the second stage gave the highest Fvs for lettuce and grains, with geometric means of 0.21 and 0.01, respectively. However, wheat-straw showed remarkable increase in Fv for the latest contamination (ripening stage), about 0.06. It could be concluded that soil contamination at early growth stages would represent high radiological risk for the scenarios studied with an exception to (137)Cs in winter wheat-straw which reflected greater hazard at the latest application. PMID:26318772

  20. Phosphorus recovery from wastewater by struvite crystallization: property of aggregates.

    PubMed

    Ye, Zhilong; Shen, Yin; Ye, Xin; Zhang, Zhaoji; Chen, Shaohua; Shi, Jianwen

    2014-05-01

    Struvite crystallization is a promising method to remove and recover phosphorus from wastewater to ease both the scarcity of phosphorus rock resources and water eutrophication worldwide. To date, although various kinds of reactor systems have been developed, supporting methods are required to control the struvite fines flushing out of the reactors. As an intrinsic property, aggregation is normally disregarded in the struvite crystallization process, although it is the key factor in final particle size and therefore guarantees phosphorus recovery efficiency. The present study developed a method to analyze the characteristics of struvite aggregates using fractal geometry, and the influence of operational parameters on struvite aggregation was evaluated. Due to its typical orthorhombic molecular structure, struvite particles are prone to crystallize into needle or rod shapes, and aggregate at the corners or edges of crystals. The determined fractal dimension (Dpf) of struvite aggregates was 1.52-1.31, with the corresponding range of equivalent diameter (d0.5) at 295.9-85.4 μm. Aggregates formed in relatively low phosphorus concentrations (3.0-5.0 mmol/L) and mildly alkaline conditions (pH 9.0-9.5) displayed relatively compact structures, large aggregate sizes and high aggregation strength. Increasing pH values led to continuous decrease of aggregate sizes, while the variation of Dpf was insignificant. As to the aggregate evolution, fast growth in a short time followed by a long steady stage was observed. PMID:25079629

  1. Individual Preferences and Social Interactions Determine the Aggregation of Woodlice

    PubMed Central

    Devigne, Cédric; Broly, Pierre; Deneubourg, Jean-Louis

    2011-01-01

    Background The aggregation of woodlice in dark and moist places is considered an adaptation to land life and most studies are focused on its functionality or on the behavioural mechanisms related to the individual's response to abiotic factors. Until now, no clear experimental demonstration was available about aggregation resulting from inter-attraction between conspecifics. Methodology/Main Findings We present the dynamics of aggregation, not previously described in detail in literature, as being independent of the experimental conditions: homogeneous and heterogeneous environments with identical or different shelters. Indeed whatever these conditions, the aggregation is very quick. In less than 10 minutes more than 50% of woodlice were aggregated in several small groups in the homogeneous environment or under shelters in the heterogeneous environment. After this fast aggregation, woodlice progressively moved into a single aggregate or under one shelter. Conclusions/Significance Here we show for the first time that aggregation in woodlice implies a strong social component and results from a trade-off between individual preferences and inter-attraction between individuals. Moreover, our results reveal that the response to the heterogeneities affects only the location of the aggregates and not the level of aggregation, and demonstrate the strong inter-attraction between conspecifics which can outweigh individual preferences. This inter-attraction can lead to situations that could seem sub-optimal. PMID:21364761

  2. Robotic technology evolution and transfer

    NASA Technical Reports Server (NTRS)

    Marzwell, Neville I.

    1992-01-01

    A report concerning technology transfer in the area of robotics is presented in vugraph form. The following topics are discussed: definition of technology innovation and tech-transfer; concepts relevant for understanding tech-transfer; models advanced to portray tech-transfer process; factors identified as promoting tech-transfer; factors identified as impeding tech-transfer; what important roles do individuals fulfill in tech-transfer; federal infrastructure for promoting tech-transfer; federal infrastructure for promoting tech-transfer; robotic technology evolution; robotic technology transferred; and recommendations for successful robotics tech-transfer.

  3. Photophoretic force on aggregate grains

    NASA Astrophysics Data System (ADS)

    Matthews, Lorin S.; Kimery, Jesse B.; Wurm, Gerhard; de Beule, Caroline; Kuepper, Markus; Hyde, Truell W.

    2016-01-01

    The photophoretic force may impact planetary formation by selectively moving solid particles based on their composition and structure. This generates collision velocities between grains of different sizes and sorts the dust in protoplanetary discs by composition. This numerical simulation studied the photophoretic force acting on fractal dust aggregates of μm-scale radii. Results show that aggregates tend to have greater photophoretic drift velocities than spheres of similar mass or radii, though with a greater spread in the velocity. While the drift velocities of compact aggregates continue to increase as the aggregates grow larger in size, fluffy aggregates have drift velocities which are relatively constant with size. Aggregates formed from an initially polydisperse size distribution of dust grains behave differently from aggregates formed from a monodisperse population, having smaller drift velocities with directions which deviate substantially from the direction of illumination. Results agree with microgravity experiments which show the difference of photophoretic forces with aggregation state.

  4. Protein aggregates in Huntington's disease.

    PubMed

    Arrasate, Montserrat; Finkbeiner, Steven

    2012-11-01

    Huntington's disease (HD) is an incurable neurodegenerative disease characterized by abnormal motor movements, personality changes, and early death. HD is caused by a mutation in the IT-15 gene that expands abnormally the number of CAG nucleotide repeats. As a result, the translated protein huntingtin contains disease-causing expansions of glutamines (polyQ) that make it prone to misfold and aggregate. While the gene and mutations that cause HD are known, the mechanisms underlying HD pathogenesis are not. Here we will review the state of knowledge of HD, focusing especially on a hallmark pathological feature-intracellular aggregates of mutant Htt called inclusion bodies (IBs). We will describe the role of IBs in the disease. We speculate that IB formation could be just one component of a broader coping response triggered by misfolded Htt whose efficacy may depend on the extent to which it clears toxic forms of mutant Htt. We will describe how IB formation might be regulated and which factors could determine different coping responses in different subsets of neurons. A differential regulation of IB formation as a function of the cellular context could, eventually, explain part of the neuronal vulnerability observed in HD. PMID:22200539

  5. Metaconcrete: designed aggregates to enhance dynamic performance

    NASA Astrophysics Data System (ADS)

    Mitchell, Stephanie J.; Pandolfi, Anna; Ortiz, Michael

    2014-04-01

    We propose a new type of concrete for the attenuation of elastic waves induced by dynamic excitation. In this metamaterial, which we call metaconcrete, the stone, sand, and gravel aggregates of standard concrete are replaced with spherical inclusions consisting of a heavy metal core coated with a soft outer layer. These engineered aggregates can be tuned so that particular frequencies of a propagating blast wave will activate resonant oscillations of the heavy mass within the inclusions. The resonant behavior causes the system to exhibit negative effective mass, and this interaction between the wave motion and the resonant aggregates results in the attenuation of the applied dynamic loading. We introduce the concept of negative mass by deriving the effective momentum mass for the system and we define the geometrical and material parameters for the design of resonant aggregates. We develop finite element models for the analysis of metaconcrete behavior, defining a section of slab containing a periodic arrangement of inclusions. By computing the energy histories for the system when subject to a blast load, we show that there is a transfer of energy between the inclusions and the surrounding mortar. The inclusions are able to absorb a significant portion of the applied energy, resulting in a reduction in the amount of stress carried by the mortar phase and greatly improving the ability of the material to resist damage under explosive dynamic loading.

  6. Microwave fields have little effect on α-synuclein aggregation in a Caenorhabditis elegans model of Parkinson's disease.

    PubMed

    de Pomerai, David I; Iqbal, Nooria; Lafayette, Ivan; Nagarajan, Archana; Kaviani Moghadam, Mehri; Fineberg, April; Reader, Tom; Greedy, Steve; Smartt, Chris; Thomas, David W P

    2016-02-01

    Potential health effects of radiofrequency (RF) radiation from mobile phones arouse widespread public concern. RF fields from handheld devices near the brain might trigger or aggravate brain tumors or neurodegenerative diseases such as Parkinson's disease (PD). Aggregation of neural α-synuclein (S) is central to PD pathophysiology, and invertebrate models expressing human S have helped elucidate factors affecting the aggregation process. We have recently developed a transgenic strain of Caenorhabditis elegans carrying two S constructs: SC tagged with cyan (C) blue fluorescent protein (CFP), and SV with the Venus (V) variant of yellow fluorescent protein (YFP). During S aggregation in these SC+SV worms, CFP, and YFP tags are brought close enough to allow Foerster Resonance Energy Transfer (FRET). As a positive control, S aggregation was promoted at low Hg(2+) concentrations, whereas higher concentrations activated stress-response genes. Using two different exposure systems described previously, we tested whether RF fields (1.0 GHz CW, 0.002-0.02 W kg(-1); 1.8 GHz CW or GSM, 1.8 W kg(-1)) could influence S aggregation in SC+SV worms. YFP fluorescence in similar SV-only worms provided internal controls, which should show opposite changes due to FRET quenching during S aggregation. No statistically significant changes were observed over several independent runs at 2.5, 24, or 96 h. Although our worm model is sensitive to chemical promoters of aggregation, no similar effects were attributable to RF exposures. PMID:26879225

  7. Aggregation kinetics and structure of cryoimmunoglobulins clusters

    NASA Astrophysics Data System (ADS)

    Spirito, M. De; Chiappini, R.; Bassi, F. Andreasi; Stasio, E. Di; Giardina, B.; Arcovito, G.

    2002-02-01

    Cryoimmunoglobulins are pathological antibodies characterized by a temperature-dependent reversible insolubility. Rheumatoid factors (RF) are immunoglobulins possessing anti-immunoglobulin activity and usually consist of an IgM antibody that recognizes IgG as antigen. These proteins are present in sera of patients affected by a large variety of different pathologies, such as HCV infection, neoplastic and autoimmune diseases. Aggregation and precipitation of cryoimmunoglobulins, leading to vasculiti, are physical phenomena behind such pathologies. A deep knowledge of the physico-chemical mechanisms regulating such phenomena plays a fundamental role in biological and clinical applications. In this work, a preliminary investigation of the aggregation kinetics and of the final macromolecular structure of the aggregates is presented. Through static light scattering techniques, the gyration radius Rg and the fractal dimension Dm of the growing clusters have been determined. However, while the initial aggregation mechanism could be described using the universal reaction-limited cluster-cluster aggregation (RLCCA) theory, at longest times from the beginning of the process, the RLCCA theory fails and a restructuring of clusters is observed together with an increase of the cluster fractal dimension Dm up to a value Dm∼3. The time tn, at which the restructuring takes place, and the final cluster size can be modulated by varying the quenching temperature.

  8. Hydrogen-bonded aggregates in precise acid copolymers

    SciTech Connect

    Lueth, Christopher A.; Bolintineanu, Dan S.; Stevens, Mark J. Frischknecht, Amalie L.

    2014-02-07

    We perform atomistic molecular dynamics simulations of melts of four precise acid copolymers, two poly(ethylene-co-acrylic acid) (PEAA) copolymers, and two poly(ethylene-co-sulfonic acid) (PESA) copolymers. The acid groups are spaced by either 9 or 21 carbons along the polymer backbones. Hydrogen bonding causes the acid groups to form aggregates. These aggregates give rise to a low wavevector peak in the structure factors, in agreement with X-ray scattering data for the PEAA materials. The structure factors for the PESA copolymers are very similar to those for the PEAA copolymers, indicating a similar distance between aggregates which depends on the spacer length but not on the nature of the acid group. The PEAA copolymers are found to form more dimers and other small aggregates than do the PESA copolymers, while the PESA copolymers have both more free acid groups and more large aggregates.

  9. Dynamics of fire ant aggregations

    NASA Astrophysics Data System (ADS)

    Tennenbaum, Michael; Hu, David; Fernandez-Nieves, Alberto

    Fire ant aggregations are an inherently active system. Each ant harvests its own energy and can convert it into motion. The motion of individual ants contributes non-trivially to the bulk material properties of the aggregation. We have measured some of these properties using plate-plate rheology, where the response to an applied external force or deformation is measured. In this talk, we will present data pertaining to the aggregation behavior in the absence of any external force. We quantify the aggregation dynamics by monitoring the rotation of the top plate and by measuring the normal force. We then compare the results with visualizations of 2D aggregations.

  10. A compilation of radionuclide transfer factors for the plant, meat, milk, and aquatic food pathways and the suggested default values for the RESRAD code

    SciTech Connect

    Wang, Y.Y.; Biwer, B.M.; Yu, C.

    1993-08-01

    The ongoing development and revision of the RESRAD computer code at Argonne National Laboratory requires update of radionuclide transfer factors for the plant, meat, milk, and aquatic food pathways. Default values for these transfer factors used in published radiological assessment reports are compiled and compared with values used in RESRAD. The differences among the reported default values used in different radiological assessment codes and reports are also discussed. In data comparisons, values used in more recent reports are given more weight because more recent experimental work tends to be conducted under better-defined laboratory or field conditions. A new default value is suggested for RESRAD if one of the following conditions is met: (1) values used in recent reports are an order of magnitude higher or lower than the default value currently used in RESRAD, or (2) the same default value is used in several recent radiological assessment reports.

  11. DEVELOPMENT AND EVALUATION OF AN AGGREGATE SURFACE SAMPLING METHOD FOR USE IN ASSESSING DERMAL EXPOSURES OF YOUNG CHILDREN

    EPA Science Inventory

    In the macroactivity approach, dermal exposure is estimated using empirically-derived transfer coefficients to aggregate the mass transfer associated with a series of contacts with a contaminated medium. The macroactivity approach affords the possibility of developing screenin...

  12. Measurements of the proton elastic-form-factor ratio mu pG p E/G p M at low momentum transfer.

    PubMed

    Ron, G; Glister, J; Lee, B; Allada, K; Armstrong, W; Arrington, J; Beck, A; Benmokhtar, F; Berman, B L; Boeglin, W; Brash, E; Camsonne, A; Calarco, J; Chen, J P; Choi, Seonho; Chudakov, E; Coman, L; Craver, B; Cusanno, F; Dumas, J; Dutta, C; Feuerbach, R; Freyberger, A; Frullani, S; Garibaldi, F; Gilman, R; Hansen, O; Higinbotham, D W; Holmstrom, T; Hyde, C E; Ibrahim, H; Ilieva, Y; de Jager, C W; Jiang, X; Jones, M K; Kang, H; Kelleher, A; Khrosinkova, E; Kuchina, E; Kumbartzki, G; LeRose, J J; Lindgren, R; Markowitz, P; May-Tal Beck, S; McCullough, E; Meekins, D; Meziane, M; Meziani, Z-E; Michaels, R; Moffit, B; Norum, B E; Oh, Y; Olson, M; Paolone, M; Paschke, K; Perdrisat, C F; Piasetzky, E; Potokar, M; Pomatsalyuk, R; Pomerantz, I; Puckett, A; Punjabi, V; Qian, X; Qiang, Y; Ransome, R; Reyhan, M; Roche, J; Rousseau, Y; Saha, A; Sarty, A J; Sawatzky, B; Schulte, E; Shabestari, M; Shahinyan, A; Shneor, R; Sirca, S; Slifer, K; Solvignon, P; Song, J; Sparks, R; Subedi, R; Strauch, S; Urciuoli, G M; Wang, K; Wojtsekhowski, B; Yan, X; Yao, H; Zhan, X; Zhu, X

    2007-11-16

    High-precision measurements of the proton elastic form-factor ratio, mu pG p E/G p M, have been made at four-momentum transfer, Q2, values between 0.2 and 0.5 GeV2. The new data, while consistent with previous results, clearly show a ratio less than unity and significant differences from the central values of several recent phenomenological fits. By combining the new form-factor ratio data with an existing cross-section measurement, one finds that in this Q2 range the deviation from unity is primarily due to G p E being smaller than expected. PMID:18233135

  13. Making Graphene Resist Aggregation

    NASA Astrophysics Data System (ADS)

    Luo, Jiayan

    Graphene-based sheets have stimulated great interest in many scientific disciplines and shown promise for wide potential applications. Among various ways of creating single atomic layer carbon sheets, a promising route for bulk production is to first chemically exfoliate graphite powders to graphene oxide (GO) sheets, followed by reduction to form chemically modified graphene (CMG). Due to the strong van der Waals attraction between graphene sheets, CMG tends to aggregate. The restacking of sheets is largely uncontrollable and irreversible, thus it reduces their processability and compromises properties such as accessible surface area. Strategies based on colloidal chemistry have been applied to keep CMG dispersed in solvents by introducing electrostatic repulsion to overcome the van der Waals attraction or adding spacers to increase the inter-sheet spacing. In this dissertation, two very different ideas that can prevent CMG aggregation without extensively modifying the material or introducing foreign spacer materials are introduced. The van der Waals potential decreases with reduced overlapping area between sheets. For CMG, reducing the lateral dimension from micrometer to nanometer scale should greatly enhance their colloidal stability with additional advantages of increased charge density and decreased probability to interact. The enhanced colloidal stability of GO and CMG nanocolloids makes them especially promising for spectroscopy based bio-sensing applications. For potential applications in a compact bulk solid form, the sheets were converted into paper-ball like structure using capillary compression in evaporating aerosol droplets. The crumpled graphene balls are stabilized by locally folded pi-pi stacked ridges, and do not unfold or collapse during common processing steps. They can tightly pack without greatly reducing the surface area. This form of graphene leads to scalable performance in energy storage. For example, planer sheets tend to aggregate and

  14. Structure of Viral Aggregates

    NASA Astrophysics Data System (ADS)

    Barr, Stephen; Luijten, Erik

    2010-03-01

    The aggregation of virus particles is a particular form of colloidal self-assembly, since viruses of a give type are monodisperse and have identical, anisotropic surface charge distributions. In small-angle X-ray scattering experiments, the Qbeta virus was found to organize in different crystal structures in the presence of divalent salt and non-adsorbing polymer. Since a simple isotropic potential cannot explain the occurrence of all observed phases, we employ computer simulations to investigate how the surface charge distribution affects the virus interactions. Using a detailed model of the virus particle, we find an asymmetric ion distribution around the virus which gives rise to the different phases observed.

  15. From Aggregate Availability to Sustainability in California

    NASA Astrophysics Data System (ADS)

    Testa, S. M.; Parrish, J. G.

    2012-12-01

    California leads the nation in the production of sand and gravel, and ranks second behind Texas in the production of portland cement. Prior to 1960, the California Geological Survey (CGS, formerly the Division of Mines and Geology) and the State Mining and Geology Board (SMGB, formerly State Mining Board) placed an emphasis "in obtaining and providing information of benefit to the State's mineral industry". By the late 1960s, the Division initiated activities in the area of geologic hazards, and also expressed concern over the loss of aggregate resources via urbanization, which were among the state's most valuable mineral resource. Under the California Surface Mining and Reclamation Act of 1975 (SMARA), the State Geologist classifies mineral resources solely on geologic factors, and without regard to existing land use and land ownership. Following classification, the SMGB may consider "designating" such lands should the classified area contain mineral resources of regional or statewide economic significance and that may be needed to meet future demands. In 1979, the classification of aggregate resources in the three-county area of Los Angeles, Orange, and Ventura, was completed, with designation of such resources in Los Angeles County in 1981. Maps and descriptions of the designated mineral lands were placed in the California Public Resources Code and officially transmitted to those county and city governments having permitting authority over the use of those lands. In 1999, the SMGB in concert with CGS implemented the SMARA Regional Synthesis Map series, with the first (and last) of the series covering the Los Angeles Basin. This map was very useful for regional planners and the general citizenry since it provided a broader perspective not readily apparent in the smaller scale Production-Consumption (P-C) regional maps. CGS's statewide Aggregate Availability Map, commonly referred to as Map Sheet 52, was developed in 2002 and updated in 2006. The purpose of Map 52

  16. Effect of nuclear factor κB inhibition on serotype 9 adeno-associated viral (AAV9) minidystrophin gene transfer to the mdx mouse.

    PubMed

    Reay, Daniel P; Niizawa, Gabriela A; Watchko, Jon F; Daood, Molly; Reay, Ja'Nean C; Raggi, Eugene; Clemens, Paula R

    2012-01-01

    Gene therapy studies for Duchenne muscular dystrophy (DMD) have focused on viral vector-mediated gene transfer to provide therapeutic protein expression or treatment with drugs to limit dystrophic changes in muscle. The pathological activation of the nuclear factor (NF)-κB signaling pathway has emerged as an important cause of dystrophic muscle changes in muscular dystrophy. Furthermore, activation of NF-κB may inhibit gene transfer by promoting inflammation in response to the transgene or vector. Therefore, we hypothesized that inhibition of pathological NF-κB activation in muscle would complement the therapeutic benefits of dystrophin gene transfer in the mdx mouse model of DMD. Systemic gene transfer using serotype 9 adeno-associated viral (AAV9) vectors is promising for treatment of preclinical models of DMD because of vector tropism to cardiac and skeletal muscle. In quadriceps of C57BL/10ScSn-Dmd(mdx)/J (mdx) mice, the addition of octalysine (8K)-NF-κB essential modulator (NEMO)-binding domain (8K-NBD) peptide treatment to AAV9 minidystrophin gene delivery resulted in increased levels of recombinant dystrophin expression suggesting that 8K-NBD treatment promoted an environment in muscle tissue conducive to higher levels of expression. Indices of necrosis and regeneration were diminished with AAV9 gene delivery alone and to a greater degree with the addition of 8K-NBD treatment. In diaphragm muscle, high-level transgene expression was achieved with AAV9 minidystoophin gene delivery alone; therefore, improvements in histological and physiological indices were comparable in the two treatment groups. The data support benefit from 8K-NBD treatment to complement gene transfer therapy for DMD in muscle tissue that receives incomplete levels of transduction by gene transfer, which may be highly significant for clinical applications of muscle gene delivery. PMID:22231732

  17. Crushed aggregates for roads and their properties for frost protection

    NASA Astrophysics Data System (ADS)

    Kuznetsova, Elena; Willy Danielsen, Svein

    2015-04-01

    of the road system. According to new specification; the size of large stones for this layer should be maximum 0.5 m (longest edge) or ½ layer thickness. And minimum 30% of stones should be less than 90 mm. Fines content (<0.063 mm) should be maximum 15% of the material less than 22.4 mm. Analysing these new requirements, several questions are arising. First of all how this materials size will affect heat exchange in the layer, secondly - if the allowable fines content will make the materials frost susceptible. For calculations of frost protection layer thickness the knowledge of thermal conductivity of the aggregate layers is required. Handbook for geotechnical investigations of the soils provides this data for natural gravel which is limited by 0.7 - 1.3 W/mK. But when it comes to the crushed rocks, it can be significantly increased due to the higher conductivity of minerals (especially if they contain high amount of quartz), as well as due to higher effective conductivity. In rock-fill materials, i.e. materials with large particles and low degree of saturation, convection and radiation are the predominant heat transfer mechanisms. Convection and radiation can increase the effective conductivity by factor 2-10. Lebeau and Konrad (2007) showed that convection heat transfer could lead to the formation of undesirable permafrost conditions in toe drains of embankment dams located in Northern Quebec, i.e. in areas where there are no naturally occurring permafrost soils. In a frost design method the required parameter values of crushed rock aggregates are thermal conductivity, density and water content. The heat transfer during the freezing of natural soils is assumed proportional to thermal conductivity of the material. In a coarse-grained material with abundant pore space, convective heat transfer and radiation may be a considerable factor, sometimes even more significant than conduction. Specifications used by pavement engineers in most countries are solely based on

  18. Assessing Student Expertise in Introductory Physics with Isomorphic Problems. II. Effect of Some Potential Factors on Problem Solving and Transfer

    ERIC Educational Resources Information Center

    Chandralekha; Singh

    2008-01-01

    In this paper, we explore the use of isomorphic problem pairs (IPPs) to assess introductory physics students' ability to solve and successfully transfer problem-solving knowledge from one context to another in mechanics. We call the paired problems "isomorphic" because they require the same physics principle to solve them. We analyze written…

  19. Hispanic Student Success: Factors Influencing the Persistence and Transfer Decisions of Latino Community College Students Enrolled in Developmental Education

    ERIC Educational Resources Information Center

    Crisp, Gloria; Nora, Amaury

    2010-01-01

    This study examined the impact of a set of theoretically-derived predictor variables on the persistence and transfer of Hispanic community college students. Early models of student persistence have been validated primarily among 4-year college students. While the constructs have been well-established, the relationships of those relevant factors…

  20. Examining Factors Affecting Beginning Teachers' Transfer of Learning of ICT-Enhanced Learning Activities in Their Teaching Practice

    ERIC Educational Resources Information Center

    Agyei, Douglas D.; Voogt, Joke

    2014-01-01

    This study examined 100 beginning teachers' transfer of learning when utilising Information Communication Technology-enhanced activity-based learning activities. The beginning teachers had participated in a professional development program that was characterised by "learning technology by collaborative design" in their final year of…

  1. A Comparison of Factors Related to University Students' Learning: College-Transfer and Direct-Entry from High School Students

    ERIC Educational Resources Information Center

    Acai, Anita; Newton, Genevieve

    2015-01-01

    Articulation agreements between colleges and universities, whereby students with two-year college diplomas can receive advancement toward a four-year university degree, are provincially mandated in some Canadian provinces and highly encouraged in others. In this study, we compared learning in college transfer and direct-entry from high school…

  2. Taurine and platelet aggregation

    SciTech Connect

    Nauss-Karol, C.; VanderWende, C.; Gaut, Z.N.

    1986-03-01

    Taurine is a putative neurotransmitter or neuromodulator. The endogenous taurine concentration in human platelets, determined by amino acid analysis, is 15 ..mu..M/g. In spite of this high level, taurine is actively accumulated. Uptake is saturable, Na/sup +/ and temperature dependent, and suppressed by metabolic inhibitors, structural analogues, and several classes of centrally active substances. High, medium and low affinity transport processes have been characterized, and the platelet may represent a model system for taurine transport in the CNS. When platelets were incubated with /sup 14/C-taurine for 30 minutes, then resuspended in fresh medium and reincubated for one hour, essentially all of the taurine was retained within the cells. Taurine, at concentrations ranging from 10-1000 ..mu..M, had no effect on platelet aggregation induced by ADP or epinephrine. However, taurine may have a role in platelet aggregation since 35-39% of the taurine taken up by human platelets appears to be secreted during the release reaction induced by low concentrations of either epinephrine or ADP, respectively. This release phenomenon would imply that part of the taurine taken up is stored directly in the dense bodies of the platelet.

  3. Microelectrode Measurements of the Activity Distribution in Nitrifying Bacterial Aggregates

    PubMed Central

    de Beer, D.; van den Heuvel, J. C.; Ottengraf, S. P. P.

    1993-01-01

    Microelectrodes for ammonium, oxygen, nitrate, and pH were used to study nitrifying aggregates grown in a fluidized-bed reactor. Local reactant fluxes and distribution of microbial activity could be determined from the microprofiles. The interfacial fluxes of the reactants closely reflected the stoichiometry of bacterial nitrification. Both ammonium consumption and nitrate production were localized in the outer shells, with a thickness of approximately 100 to 120 μm, of the aggregates. Under conditions in which ammonium and oxygen penetrated the whole aggregate, nitrification was restricted to this zone; oxygen was consumed in the central parts of the aggregates as well, probably because of oxidation of dead biomass. A sudden increase of the oxygen concentration to saturation (pure oxygen) was inhibitory to nitrification. The pH profiles showed acidification in the aggregates, but not to an inhibitory level. The distribution of activity was determined by the penetration depth of oxygen during aggregate development in the reactor. Mass transfer was significantly limited by the boundary layer surrounding the aggregates. Microelectrode measurements showed that the thickness of this layer was correlated with the diffusion coefficient of the species. Determination of the distribution of nitrifying activity required the use of ammonium or nitrate microelectrodes, whereas the use of oxygen microelectrodes alone would lead to erroneous results. Images PMID:16348875

  4. Synthesis and aggregation behavior of a hexameric quaternary ammonium surfactant.

    PubMed

    Fan, Yaxun; Hou, Yanbo; Xiang, Junfeng; Yu, Defeng; Wu, Chunxian; Tian, Maozhang; Han, Yuchun; Wang, Yilin

    2011-09-01

    A star-shaped hexameric quaternary ammonium surfactant (PAHB), bearing six hydrophobic chains and six charged hydrophilic headgroups connected by an amide-type spacer group, was synthesized. The self-assembly behavior of the surfactant in aqueous solution was studied by surface tension, electrical conductivity, isothermal titration microcalorimetry, dynamic light scattering, cryogenic transmission electron microscopy, and NMR techniques. The results reveal that there are two critical aggregate concentrations during the process of aggregation, namely C(1) and C(2). The aggregate transitions are proved to be caused by the changes of the surfactant configuration through hydrophobic interaction among the hydrocarbon chains. Below C(1), PAHB may present a star-shaped molecular configuration due to intramolecular electrostatic repulsion among the charged headgroups, and large aggregates with network-like structure are observed. Between C(1) and C(2), the hydrophobic interaction among the hydrophobic chains may become stronger to make the hydrophobic chains of the PAHB molecules curve back and pack more closely, and then the network-like aggregates transfer to large spherical aggregates of ∼100 nm. Beyond C(2), the hydrophobic interaction may become strong enough to cause the PAHB molecular configuration to turn into a pyramid-like shape, resulting in the transition of the spherical large aggregates to spherical micelles of ∼10 nm. Interestingly, the PAHB displays high emulsification ability to linear fatty alkyls even at very low concentration. PMID:21797217

  5. Aggregates from natural and recycled sources; economic assessments for construction applications; a materials flow study

    USGS Publications Warehouse

    Wilburn, David R.; Goonan, Thomas G.

    1998-01-01

    Increased amounts of recycled materials are being used to supplement natural aggregates (derived from crushed stone, sand and gravel) in road construction. An understanding of the economics and factors affecting the level of aggregates recycling is useful in estimating the potential for recycling and in assessing the total supply picture of aggregates. This investigation includes a descriptive analysis of the supply sources, technology, costs, incentives, deterrents, and market relationships associated with the production of aggregates.

  6. Theories Supporting Transfer of Training.

    ERIC Educational Resources Information Center

    Yamnill, Siriporn; McLean, Gary N.

    2001-01-01

    Reviews theories about factors affecting the transfer of training, including theories on motivation (expectancy, equity, goal setting), training transfer design (identical elements, principle, near and far), and transfer climate (organizational). (Contains 36 references.) (SK)

  7. Apple Procyanidins Suppress Amyloid β-Protein Aggregation

    PubMed Central

    Toda, Toshihiko; Sunagawa, Tadahiro; Kanda, Tomomasa; Tagashira, Motoyuki; Shirasawa, Takuji; Shimizu, Takahiko

    2011-01-01

    Procyanidins (PCs) are major components of the apple polyphenols (APs). We previously reported that treatment with PC extended the mean lifespan of Caenorhabditis elegans (Sunagawa et al., 2011). In order to estimate the neuroprotective effects of PC, we investigated the antiaggregative activity of PC on amyloid β-protein (Aβ) aggregation, which is a pathological hallmark of Alzheimer's disease. We herein report that PC significantly suppressed Aβ42 aggregation and dissociated Aβ42 aggregates in a dose-dependent manner, indicating that PC is a potent suppressor of Aβ aggregation. Furthermore, PC significantly inhibited Aβ42 neurotoxicity and stimulated proliferation in PC-12 cells. These results suggested that the PC and AP acted as neuroprotective factors against toxic Aβ aggregates. PMID:21826271

  8. Aggregation dynamics of rigid polyelectrolytes

    NASA Astrophysics Data System (ADS)

    Tom, Anvy Moly; Rajesh, R.; Vemparala, Satyavani

    2016-01-01

    Similarly charged polyelectrolytes are known to attract each other and aggregate into bundles when the charge density of the polymers exceeds a critical value that depends on the valency of the counterions. The dynamics of aggregation of such rigid polyelectrolytes are studied using large scale molecular dynamics simulations. We find that the morphology of the aggregates depends on the value of the charge density of the polymers. For values close to the critical value, the shape of the aggregates is cylindrical with height equal to the length of a single polyelectrolyte chain. However, for larger values of charge, the linear extent of the aggregates increases as more and more polymers aggregate. In both the cases, we show that the number of aggregates decrease with time as power laws with exponents that are not numerically distinguishable from each other and are independent of charge density of the polymers, valency of the counterions, density, and length of the polyelectrolyte chain. We model the aggregation dynamics using the Smoluchowski coagulation equation with kernels determined from the molecular dynamics simulations and justify the numerically obtained value of the exponent. Our results suggest that once counterions condense, effective interactions between polyelectrolyte chains short-ranged and the aggregation of polyelectrolytes are diffusion-limited.

  9. Chorioretinitis with a combined defect in T and B lymphocytes and granulocytes. A new syndrome successfully treated with dialyzable leukocyte extracts (transfer factor).

    PubMed

    Kyong, C U; Wilson, G B; Fudenberg, H H; Goust, J M; Richardson, P; Echerd, J

    1980-06-01

    A patient with immune deficiency, recurrent pyogenic infections and active chorioretinitis is described; in addition to agammaglobulinemia, both quantitative and qualitative T-cell deficiencies were documented. Furthermore, the patient's granulocytes (polymorphonuclear leukocytes), although normal in their bactericidal capacity for Staphylococcus, responded poorly to both leukocyte migration inhibition factor and neutrophil immobilizing factor obtained from normal cells. The immunologic features of this patient appear to comprise a new syndrome. Remarkable diminution of the ocular lesions and increased visual acuity occurred within two months after the initiation of therapy with dialyzable leukocyte extracts (transfer factor). Concurrent testing of the patient's cell-mediated immunity showed increased numbers of circulating T lymphocytes and improved T-cell function following dialyzable leukocyte extract [DLE] therapy. The dramatic clinical results indicate that similar therapy may prove to be beneficial in other patients with chorioretinitis and T-cell deficiency. PMID:6992573

  10. Measurements of heat transfer coefficients and friction factors in rib-roughened channels simulating leading-edge cavities of a modern turbine blade

    SciTech Connect

    Taslim, M.E.; Li, T.; Spring, S.D.

    1997-07-01

    Leading edge cooling cavities in modern gas turbine blades play an important role in maintaining the leading edge temperature at levels consistent with air foil design life. These cavities often have a complex cross-sectional shape to be compatible with the external contour of the blade at the leading edge. A survey of many existing geometries shows that, for analytical as well as experimental analyses, such cavities can be simplified in shape by a four-sided polygon with one curved side similar to the leading edge curvature, a rectangle with one semicircular side (often the smaller side) or a trapezoid, the smaller base of which is replaced by a semicircle. Furthermore, to enhance the heat transfer coefficient in these cavities, they are mostly roughened on three sides with ribs of different geometries. Experimental data on friction factors and heat transfer coefficients in such cavities are rare if not nonexistent. A liquid crystal technique was used in this experimental investigation to measure heat transfer coefficients in six test sections representing the leading-edge cooling cavities. Both straight and tapered ribs were configured on the two opposite sidewalls in a staggered arrangement with angles of attack to the mainstream flow, {alpha}, of 60 and 90 deg. The ribs on the curved surface were of constant cross section with an angle of attack 90 deg to the flow. Heat transfer measurements were performed on the straight sidewalls, as well as on the round surface adjacent to the blade leading edge. Effects such as rib angle of attack to the mainstream flow and constant versus tapered rib cross-sectional areas were also investigated. Nusselt numbers, friction factors, and thermal performances are reported for nine rib geometries in six test sections.

  11. Technology Transfer Issues and a New Technology Transfer Model

    ERIC Educational Resources Information Center

    Choi, Hee Jun

    2009-01-01

    The following are major issues that should be considered for efficient and effective technology transfer: conceptions of technology, technological activity and transfer, communication channels, factors affecting transfer, and models of transfer. In particular, a well-developed model of technology transfer could be used as a framework for…

  12. Neuroactive Multifunctional Tacrine Congeners with Cholinesterase, Anti-Amyloid Aggregation and Neuroprotective Properties

    PubMed Central

    Kozurkova, Maria; Hamulakova, Slavka; Gazova, Zuzana; Paulikova, Helena; Kristian, Pavol

    2011-01-01

    The review summarizes research into the highly relevant topics of cholinesterase and amyloid aggregation inhibitors connected to tacrine congeners, both of which are associated with neurogenerative diseases. Various opinions will be discussed regarding the dual binding site inhibitors which are characterized by increased inhibitor potency against acetylcholin/butyrylcholine esterase and amyloid formation. It is suggested that these compounds can both raise levels of acetylcholine by binding to the active site, and also prevent amyloid aggregation. In connection with this problem, the mono/dual binding of the multifunctional derivatives of tacrine, their mode of action and their neuroprotective activities are reported. The influence of low molecular compounds on protein amyloid aggregation, which might be considered as a potential therapeutic strategy in the treatment of Alzheimer's disease is also reported. Finally, attention is paid to some physico-chemical factors, such as desolvation energies describing the transfer of the substrate solvated by water, the metal-chelating properties of biometals reacting with amyloid precursor protein, amyloid beta peptide and tau protein.

  13. Exploring the Contextual Factors Related to Transfer of Learning in a High School Implementation of the eMINTS Program

    ERIC Educational Resources Information Center

    Kaplan, Lorie F.

    2011-01-01

    Truly impacting teacher practices is a challenge for educational professional development (PD) providers. Typically, little attention is paid to the factors within the environment to which the educators return and how those factors will impact participants' ability to integrate what they have learned into their teaching practices. Even for…

  14. Shaping the Growth Behaviour of Biofilms Initiated from Bacterial Aggregates.

    PubMed

    Melaugh, Gavin; Hutchison, Jaime; Kragh, Kasper Nørskov; Irie, Yasuhiko; Roberts, Aled; Bjarnsholt, Thomas; Diggle, Stephen P; Gordon, Vernita D; Allen, Rosalind J

    2016-01-01

    Bacterial biofilms are usually assumed to originate from individual cells deposited on a surface. However, many biofilm-forming bacteria tend to aggregate in the planktonic phase so that it is possible that many natural and infectious biofilms originate wholly or partially from pre-formed cell aggregates. Here, we use agent-based computer simulations to investigate the role of pre-formed aggregates in biofilm development. Focusing on the initial shape the aggregate forms on the surface, we find that the degree of spreading of an aggregate on a surface can play an important role in determining its eventual fate during biofilm development. Specifically, initially spread aggregates perform better when competition with surrounding unaggregated bacterial cells is low, while initially rounded aggregates perform better when competition with surrounding unaggregated cells is high. These contrasting outcomes are governed by a trade-off between aggregate surface area and height. Our results provide new insight into biofilm formation and development, and reveal new factors that may be at play in the social evolution of biofilm communities. PMID:26934187

  15. Shaping the Growth Behaviour of Biofilms Initiated from Bacterial Aggregates

    PubMed Central

    Melaugh, Gavin; Hutchison, Jaime; Kragh, Kasper Nørskov; Irie, Yasuhiko; Roberts, Aled; Bjarnsholt, Thomas; Diggle, Stephen P.; Gordon, Vernita D.; Allen, Rosalind J.

    2016-01-01

    Bacterial biofilms are usually assumed to originate from individual cells deposited on a surface. However, many biofilm-forming bacteria tend to aggregate in the planktonic phase so that it is possible that many natural and infectious biofilms originate wholly or partially from pre-formed cell aggregates. Here, we use agent-based computer simulations to investigate the role of pre-formed aggregates in biofilm development. Focusing on the initial shape the aggregate forms on the surface, we find that the degree of spreading of an aggregate on a surface can play an important role in determining its eventual fate during biofilm development. Specifically, initially spread aggregates perform better when competition with surrounding unaggregated bacterial cells is low, while initially rounded aggregates perform better when competition with surrounding unaggregated cells is high. These contrasting outcomes are governed by a trade-off between aggregate surface area and height. Our results provide new insight into biofilm formation and development, and reveal new factors that may be at play in the social evolution of biofilm communities. PMID:26934187

  16. Self-aggregation and its dependence on domain size

    NASA Astrophysics Data System (ADS)

    Jeevanjee, N.; Romps, D. M.

    2012-12-01

    When evaluating a single-column model against a cloud-resolving model (CRM), the choice of CRM domain size can exert a substantial influence on the results. In particular, recent studies have shown that self-aggregation of convection in numerical models occurs only beyond a certain threshold domain size of about 200-300 km. We present evidence that, in the absence of cold pools, self-aggregation can actually occur in any size domain, implying that self-aggregation is a more universal tendency than previously thought. At small (~ 50 km) domains, however, the degree of aggregation (as measured by the precipitable water in the dry region) is quite small. As the domain size increases, though, the degree of aggregation increases as well, peaking in the same 200-300 km regime in which the transition from un-aggregated to self-aggregated convection (with cold pools) has been seen to occur. We will discuss some of the factors responsible for setting this scale. 2D horizontal plots of boundary-layer specific humidity for different domain sizes. The different degrees of aggregation are evident

  17. Influence of porosity on collisions between dust aggregates

    NASA Astrophysics Data System (ADS)

    Gunkelmann, Nina; Ringl, Christian; Urbassek, Herbert M.

    2016-04-01

    Context. Collisions between dust particles may lead to agglomerate growth or fragmentation, depending on the porosity of the dust and the collision velocity. Aims: We study the effect of agglomerate porosity and collision velocity on aggregate fragmentation and agglomeration. Methods: Granular-mechanics simulations are used to study the outcome of head-on dust aggregate collisions. The aggregates are composed of silica grains of 0.76 μm radius and have filling factors of between 0.08 and 0.21. The simulations incorporate repulsive and viscoelastic, dissipative normal forces, and intergrain adhesion. The tangential forces are composed of gliding, rolling, and torsional friction. To study the effect of aggregate porosity, we prepared spherical aggregates with identical radius but differing particle numbers. Results: The threshold velocity for agglomerate fragmentation decreases with the porosity of the aggregates. Porous aggregates tend to fragment more easily, and the fragments are irregularly shaped. In the agglomeration regime, the merged aggregate is more compact than the initial collision partners. The collision velocity at which compaction is highest is independent of the initial porosity.

  18. Experimental determination of average turbulent heat transfer and friction factor in stator internal rib-roughened cooling channels.

    PubMed

    Battisti, L; Baggio, P

    2001-05-01

    In gas turbine cooling design, techniques for heat extraction from the surfaces exposed to the hot stream are based on the increase of the inner heat transfer areas and on the promotion of the turbulence of the cooling flow. This is currently obtained by casting periodic ribs on one or more sides of the serpentine passages into the core of the blade. Fluid dynamic and thermal behaviour of the cooling flow have been extensively investigated by means of experimental facilities and many papers dealing with this subject have appeared in the latest years. The evaluation of the average value of the heat transfer coefficient most of the time is inferred from local measurements obtained by various experimental techniques. Moreover the great majority of these studies are not concerned with the overall average heat transfer coefficient for the combined ribs and region between them, but do focus just on one of them. This paper presents an attempt to collect information about the average Nusselt number inside a straight ribbed duct. Series of measurements have been performed in steady state eliminating the error sources inherently connected with transient methods. A low speed wind tunnel, operating in steady state flow, has been built to simulate the actual flow condition occurring in a rectilinear blade cooling channel. A straight square channel with 20 transverse ribs on two sides has been tested for Re of about 3 x 10(4), 4.5 x 10(4) and 6 x 10(4). The ribbed wall test section is electrically heated and the heat removed by a stationary flow of known thermal and fluid dynamic characteristics. PMID:11460662

  19. Factors Determining the Efficiency of Porcine Somatic Cell Nuclear Transfer: Data Analysis with Over 200,000 Reconstructed Embryos.

    PubMed

    Liu, Tianbin; Dou, Hongwei; Xiang, Xi; Li, Lin; Li, Yong; Lin, Lin; Pang, Xinzhi; Zhang, Yijie; Chen, Yu; Luan, Jing; Xu, Ying; Yang, Zhenzhen; Yang, Wenxian; Liu, Huan; Li, Feida; Wang, Hui; Yang, Huanming; Bolund, Lars; Vajta, Gabor; Du, Yutao

    2015-12-01

    Data analysis in somatic cell nuclear transfer (SCNT) research is usually limited to several hundreds or thousands of reconstructed embryos. Here, we report mass results obtained with an established and consistent porcine SCNT system (handmade cloning [HMC]). During the experimental period, 228,230 reconstructed embryos and 82,969 blastocysts were produced. After being transferred into 656 recipients, 1070 piglets were obtained. First, the effects of different types of donor cells, including fetal fibroblasts (FFs), adult fibroblasts (AFs), adult preadipocytes (APs), and adult blood mesenchymal (BM) cells, were investigated on the further in vitro and in vivo development. Compared to adult donor cells (AFs, APs, BM cells, respectively), FF cells resulted in a lower blastocyst/reconstructed embryo rate (30.38% vs. 37.94%, 34.65%, and 34.87%, respectively), but a higher overall efficiency on the number of piglets born alive per total blastocysts transferred (1.50% vs. 0.86%, 1.03%, and 0.91%, respectively) and a lower rate of developmental abnormalities (10.87% vs. 56.57%, 24.39%, and 51.85%, respectively). Second, recloning was performed with cloned adult fibroblasts (CAFs) and cloned fetal fibroblasts (CFFs). When CAFs were used as the nuclear donor, fewer developmental abnormalities and higher overall efficiency were observed compared to AFs (56.57% vs. 28.13% and 0.86% vs. 1.59%, respectively). However, CFFs had an opposite effect on these parameters when compared with CAFs (94.12% vs. 10.87% and 0.31% vs. 1.50%, respectively). Third, effects of genetic modification on the efficiency of SCNT were investigated with transgenic fetal fibroblasts (TFFs) and gene knockout fetal fibroblasts (KOFFs). Genetic modification of FFs increased developmental abnormalities (38.96% and 25.24% vs. 10.87% for KOFFs, TFFs, and FFs, respectively). KOFFs resulted in lower overall efficiency compared to TFFs and FFs (0.68% vs. 1.62% and 1.50%, respectively). In conclusion, this is the

  20. Cluster-cluster aggregation simulation in a concentrated suspension.

    PubMed

    Kusaka, Yasuyuki; Fukasawa, Tomonori; Adachi, Yasuhisa

    2011-11-01

    The collision radius of a floc is an indispensable parameter for the precise description of the rate of aggregation during the development of particle flocs with a wide size distribution. Herein, we report on the characteristics of the collision radius of fractal aggregates formed by off-lattice diffusion-limited cluster-cluster aggregation (DLCCA) simulations, and discuss aggregation kinetics based on the value of the estimated collision radius. The collision radius has a fractal relationship with the number of primary particles that compose the floc. Further, the obtained fractal dimensions of flocs increase from the normally accepted value of 1.6-1.8 to a value of ~2.5 when the initial volume fraction is above 8%. From an assessment of the partial radial distribution function of the particles, the increase of the fractal dimensions determined by the collision radius can be attributed to a change in the spatial distribution of neighboring particles. The DLCCA simulation also reveals an apparent increase in the rate of aggregation upon an increase in the initial volume fraction. For a relatively low initial volume fraction, the enhancement of the aggregation rate is expressed by a population balance equation taking into account additional factors, i.e., transient collision flux among particles/flocs, excluded volumes, and polydispersed features of flocs. However, for cases with high initial volume fractions, the population balance model that accounts for these three factors overestimates the aggregation rate, which supports the concept of a caging effect. PMID:21840531

  1. Peptide aggregation in neurodegenerative disease.

    PubMed

    Murphy, Regina M

    2002-01-01

    In the not-so-distant past, insoluble aggregated protein was considered as uninteresting and bothersome as yesterday's trash. More recently, protein aggregates have enjoyed considerable scientific interest, as it has become clear that these aggregates play key roles in many diseases. In this review, we focus attention on three polypeptides: beta-amyloid, prion, and huntingtin, which are linked to three feared neurodegenerative diseases: Alzheimer's, "mad cow," and Huntington's disease, respectively. These proteins lack any significant primary sequence homology, yet their aggregates possess very similar features, specifically, high beta-sheet content, fibrillar morphology, relative insolubility, and protease resistance. Because the aggregates are noncrystalline, secrets of their structure at nanometer resolution are only slowly yielding to X-ray diffraction, solid-state NMR, and other techniques. Besides structure, the aggregates may possess similar pathways of assembly. Two alternative assembly pathways have been proposed: the nucleation-elongation and the template-assisted mode. These two modes may be complementary, not mutually exclusive. Strategies for interfering with aggregation, which may provide novel therapeutic approaches, are under development. The structural similarities between protein aggregates of dissimilar origin suggest that therapeutic strategies successful against one disease may have broad utility in others. PMID:12117755

  2. Topics in Probabilistic Judgment Aggregation

    ERIC Educational Resources Information Center

    Wang, Guanchun

    2011-01-01

    This dissertation is a compilation of several studies that are united by their relevance to probabilistic judgment aggregation. In the face of complex and uncertain events, panels of judges are frequently consulted to provide probabilistic forecasts, and aggregation of such estimates in groups often yield better results than could have been made…

  3. Mineral of the month: aggregates

    USGS Publications Warehouse

    Tepordei, Valentin V.

    2005-01-01

    Natural aggregates, consisting of crushed stone, and sand and gravel, are a major contributor to economic health, and have an amazing variety of uses. Aggregates are among the most abundant mineral resources and are major basic raw materials used by construction, agriculture and other industries that employ complex chemical and metallurgical processes.

  4. Does Shining Light on Gold Colloids Influence Aggregation?

    PubMed Central

    Bhattacharya, Susmita; Narasimha, Suda; Roy, Anushree; Banerjee, Soumitro

    2014-01-01

    In this article we revisit the much-studied behavior of self-assembled aggregates of gold colloidal particles. In the literature, the electrostatic interactions, van der Waals interactions, and the change in free energy due to ligand-ligand or ligand-solvent interactions are mainly considered to be the dominating factors in determining the characteristics of the gold aggregates. However, our light scattering and imaging experiments clearly indicate a distinct effect of light in the growth structure of the gold colloidal particles. We attribute this to the effect of a non-uniform distribution of the electric field in aggregated gold colloids under the influence of light. PMID:24909824

  5. Factors affecting the chemical exchange saturation transfer of Creatine as assessed by 11.7 T MRI.

    PubMed

    Saito, Shigeyoshi; Mori, Yuki; Tanki, Nobuyoshi; Yoshioka, Yoshichika; Murase, Kenya

    2015-01-01

    Chemical exchange saturation transfer (CEST) is a new contrast enhancement approach for imaging exogenous or endogenous substances such as creatine (Cr), amide protons, and glutamate in the human body. An increase in field strength is beneficial for CEST imaging because of the increased chemical shift and longer longitudinal relaxation time (T1). In high-field magnetic resonance imaging (MRI), establishing and evaluating the CEST effect is important for optimizing the magnetization transfer (MT) saturation radio frequency (RF) pulses. In this study, the CEST effect on Cr was evaluated at different concentrations in pH phantoms by appropriately selecting MT saturation RF pulses using 11.7 T MRI. The results showed that the CEST efficiency increased gradually with increasing applied saturation RF pulse power and that it was affected by the number of saturation RF pulses and their bandwidths. However, spillover effects were observed with higher saturation RF pulse powers. In conclusion, we successfully performed in vitro Cr CEST imaging under optimized conditions of MT saturation RF pulses. PMID:25477238

  6. Mechanics of fire ant aggregations

    NASA Astrophysics Data System (ADS)

    Tennenbaum, Michael; Liu, Zhongyang; Hu, David; Fernandez-Nieves, Alberto

    2016-01-01

    Fire ants link their bodies to form aggregations; these can adopt a variety of structures, they can drip and spread, or withstand applied loads. Here, by using oscillatory rheology, we show that fire ant aggregations are viscoelastic. We find that, at the lowest ant densities probed and in the linear regime, the elastic and viscous moduli are essentially identical over the spanned frequency range, which highlights the absence of a dominant mode of structural relaxation. As ant density increases, the elastic modulus rises, which we interpret by alluding to ant crowding and subsequent jamming. When deformed beyond the linear regime, the aggregation flows, exhibiting shear-thinning behaviour with a stress load that is comparable to the maximum load the aggregation can withstand before individual ants are torn apart. Our findings illustrate the rich, collective mechanical behaviour that can arise in aggregations of active, interacting building blocks.

  7. Mechanics of fire ant aggregations.

    PubMed

    Tennenbaum, Michael; Liu, Zhongyang; Hu, David; Fernandez-Nieves, Alberto

    2016-01-01

    Fire ants link their bodies to form aggregations; these can adopt a variety of structures, they can drip and spread, or withstand applied loads. Here, by using oscillatory rheology, we show that fire ant aggregations are viscoelastic. We find that, at the lowest ant densities probed and in the linear regime, the elastic and viscous moduli are essentially identical over the spanned frequency range, which highlights the absence of a dominant mode of structural relaxation. As ant density increases, the elastic modulus rises, which we interpret by alluding to ant crowding and subsequent jamming. When deformed beyond the linear regime, the aggregation flows, exhibiting shear-thinning behaviour with a stress load that is comparable to the maximum load the aggregation can withstand before individual ants are torn apart. Our findings illustrate the rich, collective mechanical behaviour that can arise in aggregations of active, interacting building blocks. PMID:26501413

  8. Molecular aggregation of humic substances

    USGS Publications Warehouse

    Wershaw, R. L.

    1999-01-01

    Humic substances (HS) form molecular aggregates in solution and on mineral surfaces. Elucidation of the mechanism of formation of these aggregates is important for an understanding of the interactions of HS in soils arid natural waters. The HS are formed mainly by enzymatic depolymerization and oxidation of plant biopolymers. These reactions transform the aromatic and lipid plant components into amphiphilic molecules, that is, molecules that consist of separate hydrophobic (nonpolar) and hydrophilic (polar) parts. The nonpolar parts of the molecules are composed of relatively unaltered segments of plant polymers and the polar parts of carboxylic acid groups. These amphiphiles form membrane-like aggregates on mineral surfaces and micelle-like aggregates in solution. The exterior surfaces of these aggregates are hydrophilic, and the interiors constitute separate hydrophobic liquid-like phases.

  9. Imbibition kinetics of spherical aggregates

    NASA Astrophysics Data System (ADS)

    Hébraud, Pascal; Lootens, Didier; Debacker, Alban

    The imbibition kinetics of a millimeter-sized aggregate of 300 nm diameter colloidal particles by a wetting pure solvent is studied. Three successive regimes are observed : in the first one, the imbibition proceeds by compressing the air inside the aggregate. Then, the solvent stops when the pressure of the compressed air is equal to the Laplace pressure at the meniscus of the wetting solvent in the porous aggregate. The interface is pinned and the aggregate slowly degases, up to a point where the pressure of the entrapped air stops decreasing and is controlled by the Laplace pressure of small bubbles. Depending on the curvature of the bubble, the system may then be in an unstable state. The imbibition then starts again, but with an inner pressure in equilibrium with these bubbles. This last stage leads to the complete infiltration of the aggregate.

  10. Immunogenicity of Therapeutic Protein Aggregates.

    PubMed

    Moussa, Ehab M; Panchal, Jainik P; Moorthy, Balakrishnan S; Blum, Janice S; Joubert, Marisa K; Narhi, Linda O; Topp, Elizabeth M

    2016-02-01

    Therapeutic proteins have a propensity for aggregation during manufacturing, shipping, and storage. The presence of aggregates in protein drug products can induce adverse immune responses in patients that may affect safety and efficacy, and so it is of concern to both manufacturers and regulatory agencies. In this vein, there is a lack of understanding of the physicochemical determinants of immunological responses and a lack of standardized analytical methods to survey the molecular properties of aggregates associated with immune activation. In this review, we provide an overview of the basic immune mechanisms in the context of interactions with protein aggregates. We then critically examine the literature with emphasis on the underlying immune mechanisms as they relate to aggregate properties. Finally, we highlight the gaps in our current understanding of this issue and offer recommendations for future research. PMID:26869409

  11. Transfer of Learning. Symposium.

    ERIC Educational Resources Information Center

    2002

    This document contains three papers on transfer of training and human resources. "The Effect of Organizational Support, Management Support, and Peer Support on Transfer of Training" (Susan E. Cromwell, Judith A. Kolb) reports on a longitudinal study of work environment factors that affect transfer of training in a university supervisory skills…

  12. Aggregation, lipid exchange, and metastable phases of dimyristoylphosphatidylethanolamine vesicles.

    PubMed

    Pryor, C; Bridge, M; Loew, L M

    1985-04-23

    A new fluorescent lipid analogue, bimanephosphatidylcholine, has been synthesized for use in lipid bilayers. This probe is well suited as an energy-transfer donor with N-(7-nitro-2,1,3-benzoxadiazol-4-yl)phosphatidylethanolamine as the acceptor. Dimyristoylphosphatidylethanolamine vesicles are prepared by sonication at pH 9 and characterized by electron microscopy and other methods. Resonance energy transfer between separately labeled donor and acceptor vesicles is monitored during HCl-induced aggregation to determine the kinetics of lipid randomization. Light scattering is also monitored to measure the kinetics of aggregation. The light scattering shows a marked reversal with NaOH while the energy transfer does not, indicating lipid exchange during a reversibly aggregated state; the extent of energy transfer suggests that only lipids in the outer monolayers exchange. The gel to liquid-crystalline phase transition temperature in HCl-treated vesicles is found to be 47 degrees C with diphenylhexatriene. The initial sonicated dispersion does not show a sharp phase transition. In vesicles labeled with both donor and acceptor probes, a small, irreversible increase in energy transfer is obtained upon lowering and then restoring the pH. These results suggest a metastable phase in the sonicated vesicles containing a randomized distribution of lipid and probes within the bilayers; the thermodynamically favored phase, whose formation is triggered by the pH shock, contains domains within which the probe lipids are more highly concentrated. PMID:3995010

  13. Insulin-like growth factor-1 prevents miR-122 production in neighbouring cells to curtail its intercellular transfer to ensure proliferation of human hepatoma cells

    PubMed Central

    Basu, Sudarshana; Bhattacharyya, Suvendra N.

    2014-01-01

    miRNAs are 20–22 nt long post-transcriptional regulators in metazoan cells that repress protein expression from their target mRNAs. These tiny regulatory RNAs follow tissue and cell-type specific expression pattern, aberrations of which are associated with various diseases. miR-122 is a liver-specific anti-proliferative miRNA that, we found, can be transferred via exosomes between human hepatoma cells, Huh7 and HepG2, grown in co-culture. Exosomal miR-122, expressed and released by Huh7 cells and taken by miR-122 deficient HepG2 cells, was found to be effective in repression of target mRNAs and to reduce growth and proliferation of recipient HepG2 cells. Interestingly, in a reciprocal process, HepG2 secretes Insulin-like Growth Factor 1 (IGF1) that decreases miR-122 expression in Huh7 cells. Our observations suggest existence of a reciprocal interaction between two different hepatic cells with distinct miR-122 expression profiles. This interaction is mediated via intercellular exosome-mediated miR-122 transfer and countered by a reciprocal IGF1-dependent anti-miR-122 signal. According to our data, human hepatoma cells use IGF1 to prevent intercellular exosomal transfer of miR-122 to ensure its own proliferation by preventing expression of growth retarding miR-122 in neighbouring cells. PMID:24813441

  14. The Rebound Condition of Dust Aggregates Revealed by Numerical Simulation of Their Collisions

    NASA Astrophysics Data System (ADS)

    Wada, Koji; Tanaka, Hidekazu; Suyama, Toru; Kimura, Hiroshi; Yamamoto, Tetsuo

    2011-08-01

    Collisional growth of dust aggregates is a plausible root of planetesimals forming in protoplanetary disks. However, a rebound of colliding dust aggregates prevents dust from growing into planetesimals. In fact, rebounding aggregates are observed in laboratory experiments but not in previous numerical simulations. Therefore, the condition of rebound between dust aggregates should be clarified to better understand the processes of dust growth and planetesimal formation. We have carried out numerical simulations of aggregate collisions for various types of aggregates and succeeded in reproducing a rebound of colliding aggregates under specific conditions. Our finding is that in the rebound process, the key factor of the aggregate structure is the coordination number, namely, the number of particles in contact with a particle. A rebound is governed by the energy dissipation along with restructuring of the aggregates and a large coordination number inhibits the restructuring at collisions. Results of our numerical simulation for various aggregates indicate that they stick to each other when the mean coordination number is less than 6, regardless of their materials and structures, as long as their collision velocity is less than the critical velocity for fragmentation. This criterion of the coordination number would correspond to a filling factor of ~0.3, which is somewhat larger than that reported in laboratory experiments. In protoplanetary disks, dust aggregates are expected to have low bulk densities (<0.1 g cm-3) during their growth, which would prevent dust aggregates from rebounding. This result supports the formation of planetesimals with direct dust growth in protoplanetary disks.

  15. Non-Radiative Energy Transfer Mediated by Hybrid Light-Matter States.

    PubMed

    Zhong, Xiaolan; Chervy, Thibault; Wang, Shaojun; George, Jino; Thomas, Anoop; Hutchison, James A; Devaux, Eloise; Genet, Cyriaque; Ebbesen, Thomas W

    2016-05-17

    We present direct evidence of enhanced non-radiative energy transfer between two J-aggregated cyanine dyes strongly coupled to the vacuum field of a cavity. Excitation spectroscopy and femtosecond pump-probe measurements show that the energy transfer is highly efficient when both the donor and acceptor form light-matter hybrid states with the vacuum field. The rate of energy transfer is increased by a factor of seven under those conditions as compared to the normal situation outside the cavity, with a corresponding effect on the energy transfer efficiency. The delocalized hybrid states connect the donor and acceptor molecules and clearly play the role of a bridge to enhance the rate of energy transfer. This finding has fundamental implications for coherent energy transport and light-energy harvesting. PMID:27072296

  16. Checking for reversibility of aggregation of UV-irradiated glycogen phosphorylase b under crowding conditions.

    PubMed

    Eronina, Tatiana B; Mikhaylova, Valeriya V; Chebotareva, Natalia A; Makeeva, Valentina F; Kurganov, Boris I

    2016-05-01

    It is believed that the initial stages of protein aggregation are reversible and can be reversed by simple dilution, whereas prolonged exposure to factors responsible for denaturing proteins (for example, to elevated temperatures) results in the formation of irreversible aggregates. A new approach has been developed to discriminate the stage of the formation of reversible aggregates. Aggregation of UV-irradiated glycogen phosphorylase b (UV-Phb) was studied at 10, 25 and 37°C in the presence of crowders (polyethylene glycol and Ficoll-70) using dynamic light scattering and analytical ultracentrifugation (pH 6.8; 0.1M NaCl). The dilution of the protein solution in the course of aggregation at 10°C results in the breakdown of protein aggregates suggesting that the aggregation process is reversible. When aggregation of UV-Phb is studied at 37°C, reversibility is lacking. Chemical chaperones (arginine, proline) induce the breakdown of protein aggregates of UV-Phb formed at 10°C. In the experiments carried out at 37°C in the presence of crowder the addition of arginine results in disintegration of protein aggregates only at early stages of the aggregation process. It is assumed that general pathway of protein aggregation includes the formation of reversible, completely dissociable, partly dissociable and irreversible aggregates. PMID:26853826

  17. Public Policy, Technology Adoption, and Aggregate Energy Efficiency

    SciTech Connect

    Harrington, W.; Kopp, R.J.; Morgenstern, R.D.; Pizer, W.A.; Shih, J.S.

    1999-04-01

    This research examines the factors that influence the adoption of new energy-saving technologies among U.S. manufacturing plants and explores their potential impact on aggregate energy efficiency. We conduct this analysis using two models: a conventional diffusion model and a stand-alone model of new technology adoption we develop in this paper. The latter model allows us to compute effects on aggregate efficiency based solely on adoption data.

  18. Evolution of a Sigma Factor: An All-In-One of Gene Duplication, Horizontal Gene Transfer, Purifying Selection, and Promoter Differentiation

    PubMed Central

    López-Leal, Gamaliel; Cevallos, Miguel A.; Castillo-Ramírez, Santiago

    2016-01-01

    Sigma factors are an essential part of bacterial gene regulation and have been extensively studied as far as their molecular mechanisms and protein structure are concerned. However, their molecular evolution, especially for the alternative sigma factors, is poorly understood. Here, we analyze the evolutionary forces that have shaped the rpoH sigma factors within the alphaproteobacteria. We found that an ancient duplication gave rise to two major groups of rpoH sigma factors and that after this event horizontal gene transfer (HGT) occurred in rpoH1 group. We also noted that purifying selection has differentially affected distinct parts of the gene; singularly, the gene segment that encodes the region 4.2, which interacts with the −35 motif of the RpoH-dependent genes, has been under relaxed purifying selection. Furthermore, these two major groups are clearly differentiated from one another regarding their promoter selectivity, as rpoH1 is under the transcriptional control of σ70 and σ32, whereas rpoH2 is under the transcriptional control of σ24. Our results suggest a scenario in which HGT, gene loss, variable purifying selection and clear promoter specialization occurred after the ancestral duplication event. More generally, our study offers insights into the molecular evolution of alternative sigma factors and highlights the importance of analyzing not only the coding regions but also the promoter regions. PMID:27199915

  19. Perspectives on Preference Aggregation.

    PubMed

    Regenwetter, Michel

    2009-07-01

    For centuries, the mathematical aggregation of preferences by groups, organizations, or society itself has received keen interdisciplinary attention. Extensive theoretical work in economics and political science throughout the second half of the 20th century has highlighted the idea that competing notions of rational social choice intrinsically contradict each other. This has led some researchers to consider coherent democratic decision making to be a mathematical impossibility. Recent empirical work in psychology qualifies that view. This nontechnical review sketches a quantitative research paradigm for the behavioral investigation of mathematical social choice rules on real ballots, experimental choices, or attitudinal survey data. The article poses a series of open questions. Some classical work sometimes makes assumptions about voter preferences that are descriptively invalid. Do such technical assumptions lead the theory astray? How can empirical work inform the formulation of meaningful theoretical primitives? Classical "impossibility results" leverage the fact that certain desirable mathematical properties logically cannot hold in all conceivable electorates. Do these properties nonetheless hold true in empirical distributions of preferences? Will future behavioral analyses continue to contradict the expectations of established theory? Under what conditions do competing consensus methods yield identical outcomes and why do they do so? PMID:26158988

  20. Quantifying data retention of perpendicular spin-transfer-torque magnetic random access memory chips using an effective thermal stability factor method

    SciTech Connect

    Thomas, Luc Jan, Guenole; Le, Son; Wang, Po-Kang

    2015-04-20

    The thermal stability of perpendicular Spin-Transfer-Torque Magnetic Random Access Memory (STT-MRAM) devices is investigated at chip level. Experimental data are analyzed in the framework of the Néel-Brown model including distributions of the thermal stability factor Δ. We show that in the low error rate regime important for applications, the effect of distributions of Δ can be described by a single quantity, the effective thermal stability factor Δ{sub eff}, which encompasses both the median and the standard deviation of the distributions. Data retention of memory chips can be assessed accurately by measuring Δ{sub eff} as a function of device diameter and temperature. We apply this method to show that 54 nm devices based on our perpendicular STT-MRAM design meet our 10 year data retention target up to 120 °C.

  1. Fire effects on soil aggregation: A review

    NASA Astrophysics Data System (ADS)

    Mataix-Solera, J.; Cerdà, A.; Arcenegui, V.; Jordán, A.; Zavala, L. M.

    2011-11-01

    Fire can affect soil properties depending on a number of factors including fire severity and soil type. Aggregate stability (AS) refers to soil structure resilience in response to external mechanical forces. Many authors consider soil aggregation to be a parameter reflecting soil health, as it depends on chemical, physical and biological factors. The response of AS to forest fires is complex, since it depends on how fire has affected other related properties such as organic matter content, soil microbiology, water repellency and soil mineralogy. Opinions differ concerning the effect of fire on AS. Some authors have observed a decrease in AS in soils affected by intense wildfire or severe laboratory heating. However, others have reported increases. We provide an up to date review of the research on this topic and an analysis of the causes for the different effects observed. The implications for soil system functioning and for the hydrology of the affected areas are also discussed. Generally, low severity fires do not produce notable changes in AS, although in some cases an increase has been observed and attributed to increased water repellency. In contrast, high severity fires can induce important changes in this property, but with different effects depending on the type of soil affected. The patterns observed can vary from a disaggregation as a consequence of the organic matter destruction, to a strong aggregation if a recrystallization of some minerals such as Fe and Al oxyhydroxides occurs when they are present in sufficient quantities in the soil, after exposure to high temperatures. Because of the complexity of the different possible effects and reasons for the potential changes in the fire-affected soil aggregates, the inclusion of other parameters in the studies is necessary to understand the results. The suggested parameters to include in the examination of AS are: soil organic matter, microbial biomass, water repellency, texture, aggregate size distribution

  2. Iron deficiency leads to inhibition of oxygen transfer and enhanced formation of virulence factors in cultures of Pseudomonas aeruginosa PAO1.

    PubMed

    Kim, Eun-Jin; Sabra, Wael; Zeng, An-Ping

    2003-09-01

    Pseudomonas aeruginosa PAO1 was recently found to exhibit two remarkable physiological responses to oxidative stress: (1) a strong reduction in the efficiency of oxygen transfer from the gas phase into the liquid phase, thus causing oxygen limitation in the culture and (2) formation of a clear polysaccharide capsule on the cell surface. In this work, it has been shown that the iron concentration in the culture plays a crucial role in evoking these phenomena. The physiological responses of two P. aeruginosa PAO1 isolates (NCCB 2452 and ATCC 15692) were examined in growth media with varied iron concentrations. In a computer-controlled bioreactor cultivation system for controlled dissolved oxygen tension (pO2), a strong correlation between the exhaustion of iron and the onset of oxygen limitation was observed. The oxygen transfer rate of the culture, characterized by the volumetric oxygen transfer coefficient, kLa, significantly decreased under iron-limited conditions. The formation of alginate and capsule was more strongly affected by iron concentration than by oxygen concentration. The reduction of the oxygen transfer rate and the subsequent oxygen limitation triggered by iron deficiency may represent a new and efficient way for P. aeruginosa PAO1 to adapt to growth conditions of iron limitation. Furthermore, the secretion of proteins into the culture medium was strongly enhanced by iron limitation. The formation of the virulence factor elastase and the iron chelators pyoverdine and pyochelin also significantly increased under iron-limited conditions. These results have implications for lung infection of cystic fibrosis patients by P. aeruginosa in view of the prevalence of iron limitation at the site of infection and the respiratory failure leading to death. PMID:12949186

  3. Monodisperse magnetite nanofluids: Synthesis, aggregation, and thermal conductivity

    NASA Astrophysics Data System (ADS)

    Jiang, Wei; Wang, Liqiu

    2010-12-01

    Magnetic nanofluids possess some unique properties that can significantly affect their thermal conductivity. We synthesize monodispersed magnetite (Fe3O4) nanofluids in toluene with the particle size from 4 to 12 nm and obtain aqueous nanofluids by a simple "one-step" phase transfer. Even without the effect of external field, the magnetic-interaction-induced self-assembled aggregation can still be significant in magnetite nanofluids. Investigation of the microstructures of self-assembled aggregation is carried out by the dynamic light scattering, which unveils the variation of aggregated configurations with particle concentration and time. Based on the calculation from the existing models, the aggregates decrease the thermal conductivity of both themselves and the entire system, mainly due to the less solid contents and weaker mobility compared with the single particles as well as the increase in interfacial thermal resistance. As the manifestation of the aggregation-structure variation, the measured thermal conductivity is of a wavelike shape as a function of particle concentration. The particle coating layers are also of importance in cluster formation so that nanofluid thermal conductivity can be manipulated for some nanofluids by changing the stabilizer used and thus controlling the particle aggregated structures. Due to the effects of temperature, viscosity and coating layers, the thermal conductivity for aqueous system varies in a different way as that for the toluene system.

  4. Analysis of aggregation of platelets in thrombosis

    NASA Astrophysics Data System (ADS)

    Ahuja, Suresh

    Platelets are key players in thrombus formation by first rolling over collagen bound von Willebrand factor followed by formation of a stable interaction with collagen. The first adhered platelets bind additional platelets until the whole injury is sealed off by a platelet aggregate. The coagulation system stabilizes the formed platelet plug by creating a tight fibrin network, and then wound contraction takes place because of morphological changes in platelets. Coagulation takes place by platelet activation and aggregation mainly through fibrinogen polymerization into fibrin fibers. The process includes multiple factors, such as thrombin, plasmin, and local shear-rate which regulate and control the process. Coagulation can be divided into two pathways: the intrinsic pathway and the extrinsic pathway. The intrinsic pathway is initiated by the exposure of a negatively charged. It is able to activate factor XII, using a complex reaction that includes prekallikrein and high-molecular-weight kininogen as cofactors.. Thrombin is the final enzyme that is needed to convert fibrinogen into fibrin. The extrinsic pathway starts with the exposure of tissue factor to the circulating blood, which is the major initiator of coagulation. There are several feedback loops that reinforce the coagulation cascade, resulting in large amounts of thrombin. It is dependent on the presence of pro-coagulant surfaces of cells expressing negatively charged phospholipids--which include phosphatidylserine (PS)--on their outer membrane. PS-bearing surfaces are able to increase the efficiency of the reactions by concentrating and co-localizing coagulation factors.. Aggregation of platelets are analyzed and compared to adhesion of platelet to erythrocyte and to endothelial cells. This abstract is replacing MAR16-2015-020003.

  5. Scalable evaluation of platelet aggregation by the degree of blood migration

    NASA Astrophysics Data System (ADS)

    Song, Suk-Heung; Lim, Chae-Seung; Shin, Sehyun

    2013-12-01

    Platelet aggregation plays a key role in vascular thrombosis. Antiplatelet drug therapy is commonly used for the prevention of abnormal platelet aggregation. So, measuring platelet aggregation function is critically important in clinical field. Here, we introduce a scalable evaluation method of platelet aggregation measured with the degree of blood migration through microchannel in a microfluidic chip. Unlike conventional methods that require expertise with system physics to operate devices, our approach is using microfluidics system, which requires only a syringe vacuum. The scalable migration factors, migration distance and touchdown time, are capable of distinguishing various antiplatelet drug effects under microfluidics and would be effective for the quick and easy evaluation of quantitative platelet aggregation.

  6. A Measurement of the neutron electric form factor at very large momentum transfer using polaried electrions scattering from a polarized helium-3 target

    SciTech Connect

    Kelleher, Aidan

    2010-02-01

    Knowledge of the electric and magnetic elastic form factors of the nucleon is essential for an understanding of nucleon structure. Of the form factors, the electric form factor of the neutron has been measured over the smallest range in Q2 and with the lowest precision. Jefferson Lab experiment 02-013 used a novel new polarized 3 He target to nearly double the range of momentum transfer in which the neutron form factor has been studied and to measure it with much higher precision. Polarized electrons were scattered off this target, and both the scattered electron and neutron were detected. Gn E was measured to be 0.0242 ± 0.0020(stat) ± 0.0061(sys) and 0.0247 ± 0.0029(stat) ± 0.0031(sys) at Q2 = 1.7 and 2.5 GeV2 , respectively.

  7. Network tuned multiple rank aggregation and applications to gene ranking

    PubMed Central

    2015-01-01

    With the development of various high throughput technologies and analysis methods, researchers can study different aspects of a biological phenomenon simultaneously or one aspect repeatedly with different experimental techniques and analysis methods. The output from each study is a rank list of components of interest. Aggregation of the rank lists of components, such as proteins, genes and single nucleotide variants (SNV), produced by these experiments has been proven to be helpful in both filtering the noise and bringing forth a more complete understanding of the biological problems. Current available rank aggregation methods do not consider the network information that has been observed to provide vital contributions in many data integration studies. We developed network tuned rank aggregation methods incorporating network information and demonstrated its superior performance over aggregation methods without network information. The methods are tested on predicting the Gene Ontology function of yeast proteins. We validate the methods using combinations of three gene expression data sets and three protein interaction networks as well as an integrated network by combining the three networks. Results show that the aggregated rank lists are more meaningful if protein interaction network is incorporated. Among the methods compared, CGI_RRA and CGI_Endeavour, which integrate rank lists with networks using CGI [1] followed by rank aggregation using either robust rank aggregation (RRA) [2] or Endeavour [3] perform the best. Finally, we use the methods to locate target genes of transcription factors. PMID:25708095

  8. Role of Ionic Strength in Staphylococcal Cell Aggregation.

    PubMed

    Vanzieleghem, Thomas; Couniot, Numa; Herman-Bausier, Philippe; Flandre, Denis; Dufrêne, Yves F; Mahillon, Jacques

    2016-07-26

    Cell aggregation plays a key role in biofilm formation and pathogenesis of Staphylococcus species. Although the molecular basis of aggregation in Staphylococci has already been extensively investigated, the influence of environmental factors, such as ionic strength, remains poorly understood. In this paper, we report a new type of cellular aggregation of Staphylococci that depends solely on ionic strength. Seven strains out of 14, all belonging to staphylococcal species, formed large cell clusters within minutes in buffers of ionic strength ranging from 1.5 to 50 mM, whereas isolates belonging to other Gram-positive species did not display this phenotype. Atomic force microscopy (AFM) with chemically functionalized tips provided direct evidence that ionic strength modulates cell surface adhesive properties through changes in cell surface charge. The optimal ionic strength for aggregation was found to be strain dependent, but in all cases, bacterial aggregates formed at an ionic strength of 1.5-50 mM were rapidly dispersed in a solution of higher ionic strength, indicating a reversibility of the cell aggregation process. These findings suggest that some staphylococcal isolates can respond to ionic strength as an external stimulus to trigger rapid cell aggregation in a way that has not yet been reported. PMID:27364477

  9. Effects of Intramolecular Distance between Amyloidogenic Domains on Amyloid Aggregation

    PubMed Central

    Ko, Ahra; Kim, Jin Ryoun

    2012-01-01

    Peptide/protein aggregation is implicated in many amyloid diseases. Some amyloidogenic peptides/proteins, such as those implicated in Alzheimer’s and Parkinson’s diseases, contain multiple amyloidogenic domains connected by “linker” sequences displaying high propensities to form turn structures. Recent studies have demonstrated the importance of physicochemical properties of each amino acid contained in the polypeptide sequences in amyloid aggregation. However, effects on aggregation related to the intramolecular distance between amyloidogenic domains, which may be determined by a linker length, have yet to be examined. In the study presented here, we created peptides containing two copies of KFFE, a simple four-residue amyloidogenic domain, connected by GS-rich linker sequences with different lengths yet similar physicochemical properties. Our experimental results indicate that aggregation occurred most rapidly when KFFE domains were connected by a linker of an intermediate length. Our experimental findings were consistent with estimated entropic contribution of a linker length toward formation of (partially) structured intermediates on the aggregation pathway. Moreover, inclusion of a relatively short linker was found to inhibit formation of aggregates with mature fibril morphology. When the results are assimilated, our study demonstrates that intramolecular distance between amyloidogenic domains is an important yet overlooked factor affecting amyloid aggregation. PMID:23202890

  10. Solubis: a webserver to reduce protein aggregation through mutation.

    PubMed

    Van Durme, Joost; De Baets, Greet; Van Der Kant, Rob; Ramakers, Meine; Ganesan, Ashok; Wilkinson, Hannah; Gallardo, Rodrigo; Rousseau, Frederic; Schymkowitz, Joost

    2016-08-01

    Protein aggregation is a major factor limiting the biotechnological and therapeutic application of many proteins, including enzymes and monoclonal antibodies. The molecular principles underlying aggregation are by now sufficiently understood to allow rational redesign of natural polypeptide sequences for decreased aggregation tendency, and hence potentially increased expression and solubility. Given that aggregation-prone regions (APRs) tend to contribute to the stability of the hydrophobic core or to functional sites of the protein, mutations in these regions have to be carefully selected in order not to disrupt protein structure or function. Therefore, we here provide access to an automated pipeline to identify mutations that reduce protein aggregation by reducing the intrinsic aggregation propensity of the sequence (using the TANGO algorithm), while taking care not to disrupt the thermodynamic stability of the native structure (using the empirical force-field FoldX). Moreover, by providing a plot of the intrinsic aggregation propensity score of APRs corrected by the local stability of that region in the folded structure, we allow users to prioritize those regions in the protein that are most in need of improvement through protein engineering. The method can be accessed at http://solubis.switchlab.org/. PMID:27284085

  11. Factors Determining the Risk of Inadvertent Retroviral Transduction of Male Germ Cells After In Utero Gene Transfer in Sheep

    PubMed Central

    Park, Paul J.; Colletti, Evan; Ozturk, Ferhat; Wood, Josh A.; Tellez, Joe; Almeida-Porada, Graça

    2009-01-01

    Abstract The possibility of permanent genetic changes to the germline is central to the bioethics of in utero gene therapy (IUGT) because of the concern of inadvertent potentially deleterious alterations to the gene pool. Despite presumed protection of the male germline due to early germ cell (GC) compartmentalization, we reported that GCs within the developing ovine testes are transduced at low levels after retrovirus-mediated IUGT, thus underscoring the need for a thorough understanding of GC development in clinically predictive models to determine the optimal time to perform IUGT and avoid germline modification. In the present studies, we used the fetal sheep model to analyze GCs for phenotype, location, proliferation, and incidence of transduction after IUGT at various fetal ages to learn when during development the nascent germline is likely to be at greatest risk of retrovirus-mediated alteration. Our studies show that although GCs were transduced at all injection ages, the levels of transduction varied by nearly 700-fold as a function of the age at transfer. After remaining largely quiescent as they migrated to/settled within nascent sex cords, GCs began active cycling before cord closure was complete, suggesting this is likely the point at which they would be most susceptible to retroviral transduction. Furthermore, we observed that compartmentalization of GCs continued into early postnatal life, suggesting the male germline may be vulnerable to low-level inadvertent retroviral vector modification throughout fetal life, but that this risk can be minimized by performing IUGT later in gestation. PMID:19301473

  12. Factors determining the risk of inadvertent retroviral transduction of male germ cells after in utero gene transfer in sheep.

    PubMed

    Park, Paul J; Colletti, Evan; Ozturk, Ferhat; Wood, Josh A; Tellez, Joe; Almeida-Porada, Graça; Porada, Christopher

    2009-03-01

    The possibility of permanent genetic changes to the germline is central to the bioethics of in utero gene therapy (IUGT) because of the concern of inadvertent potentially deleterious alterations to the gene pool. Despite presumed protection of the male germline due to early germ cell (GC) compartmentalization, we reported that GCs within the developing ovine testes are transduced at low levels after retrovirus-mediated IUGT, thus underscoring the need for a thorough understanding of GC development in clinically predictive models to determine the optimal time to perform IUGT and avoid germline modification. In the present studies, we used the fetal sheep model to analyze GCs for phenotype, location, proliferation, and incidence of transduction after IUGT at various fetal ages to learn when during development the nascent germline is likely to be at greatest risk of retrovirus-mediated alteration. Our studies show that although GCs were transduced at all injection ages, the levels of transduction varied by nearly 700-fold as a function of the age at transfer. After remaining largely quiescent as they migrated to/settled within nascent sex cords, GCs began active cycling before cord closure was complete, suggesting this is likely the point at which they would be most susceptible to retroviral transduction.Furthermore, we observed that compartmentalization of GCs continued into early postnatal life, suggesting the male germline may be vulnerable to low-level inadvertent retroviral vector modification throughout fetal life, but that this risk can be minimized by performing IUGT later in gestation. PMID:19301473

  13. Geometric radiation exchange factors for axial radiative transfer in an LWR core filled with absorbing-emitting gases

    SciTech Connect

    Chan, S.H.; Cho, D.H.

    1984-01-01

    A reactor core filled with an emitting-absorbing mixture (like steam, hydrogen gas and fission gases) is considered. Analysis is provided to evaluate axial radiative heat exchange of a rod bundle with a nonuniform axial temperature distribution. The necessary radiation exchange shape factors (geometric mean absorptance, emittance and transmittance) between segments of the complex rod bundle arrangement are presented. They are applicable to arbitrary sizes of segments, well suited for numerical computations.

  14. The delay in transfer between the emergency department and the critical care unit for patients with an acute cardiac event--in hospital factors.

    PubMed

    Grech, C; Pannell, D; Smith-Sparrow, T

    2001-11-01

    The Lyell McEwin Health Service (LMHS) is a major public hospital located in the northern suburbs of Adelaide, a region where the death rate from ischaemic heart disease (IHD) is higher than the expected death rate in the population. A retrospective case note study conducted at this hospital investigated the duration that patients with unstable angina pectoris (UA) or acute myocardial infarction (AMI) spent in the emergency department (ED) before admission to the critical care unit (CCU) and the factors that contributed to delays of greater than 70 minutes. All patients admitted to the LMHS over an 18 month period with a discharge diagnosis related group (DRG) for AMI and UA were included in the study. A total of 667 case notes were examined; 403 of these cases met the inclusion criteria for the study. The mean duration between arrival in the ED and subsequent admission to the CCU was found to be 161 minutes. DRG was a major factor in the length of time spent in the ED. The mean duration for patients with AMI was 124 minutes, whilst for UA the duration was 190 minutes (difference = 66 minutes, p<0.001). Other factors that were significant were gender (females = mean duration 29 minutes > males, p=0.015), and mode of transport to the ED (arrival by ambulance mean duration 30 minutes < private transport, Recommendations arising from this study included that a system be established to enable the rapid assessment of all patients suspected of suffering AMI and UA, inclusive of their expeditious transfer to the CCU. In addition, a staff development programme was proposed to ensure medical and nursing staff became aware of a bias in this hospital toward transferring male patients in a shorter timeframe than females with the same DRG. PMID:11806510

  15. Dye-capped semiconductor nanoclusters. Excited state and photosensitization aspects of rhodamine 6G H-aggregates bound to SiO{sub 2} and SnO{sub 2} colloids

    SciTech Connect

    Nasr, C. |; Liu, D.; Kamat, P.V.; Hotchandani, S.

    1996-06-27

    SiO{sub 2} and SnO{sub 2} colloids are capped with a cationic dye, rhodamine 6G, by electrostatic interaction. The close packing of these dye molecules on the negatively charged SiO{sub 2} and SnO{sub 2} colloid results in the formation of H-aggregates. These aggregates are nonfluorescent but can inject electrons from the excited state into SnO{sub 2} colloids. The photophysical and photochemical properties of rhodamine-6G-aggregate on SiO{sub 2} and SnO{sub 2} colloids have been investigated using picosecond laser flash photolysis. Charge injection from the excited dye aggregate into SnO{sub 2} nanocrystallites occurs with a rate constant of 5.5 x 10{sup 9} s{sup -1}. The application of these dye aggregates in extending the photoresponse of nanocrystalline SnO{sup 2} film has been demonstrated by constructing a photoelectrochemical cell. A maximum incident photon-to-photocurrent efficiency of nearly 1% was observed for the photosensitized current generation. Fast reverse electron transfer between the injected electron and the cation radical of the dye aggregate is a limiting factor in maximizing the incident photon-to-photocurrent efficiency (IPCE). 65 refs., 11 figs.

  16. Prion-like transmission of neuronal huntingtin aggregates to phagocytic glia in the Drosophila brain

    PubMed Central

    Pearce, Margaret M.P.; Spartz, Ellen J.; Hong, Weizhe; Luo, Liqun; Kopito, Ron R.

    2015-01-01

    The brain has a limited capacity to self-protect against protein aggregate-associated pathology, and mounting evidence supports a role for phagocytic glia in this process. We have established a Drosophila model to investigate the role of phagocytic glia in clearance of neuronal mutant huntingtin (Htt) aggregates associated with Huntington disease. We find that glia regulate steady-state numbers of Htt aggregates expressed in neurons through a clearance mechanism that requires the glial scavenger receptor Draper and downstream phagocytic machinery. Remarkably, some of these engulfed neuronal Htt aggregates effect prion-like conversion of soluble, wild-type Htt in the glial cytoplasm. We provide genetic evidence that this conversion depends strictly on the Draper signaling pathway, unveiling a previously unanticipated role for phagocytosis in transfer of pathogenic protein aggregates in an intact brain. These results suggest a potential mechanism by which phagocytic glia contribute to both protein aggregate-related neuroprotection and pathogenesis in neurodegenerative disease. PMID:25866135

  17. Aggregate breakdown of nanoparticulate titania

    NASA Astrophysics Data System (ADS)

    Venugopal, Navin

    Six nanosized titanium dioxide powders synthesized from a sulfate process were investigated. The targeted end-use of this powder was for a de-NOx catalyst honeycomb monolith. Alteration of synthesis parameters had resulted principally in differences in soluble ion level and specific surface area of the powders. The goal of this investigation was to understand the role of synthesis parameters in the aggregation behavior of these powders. Investigation via scanning electron microscopy of the powders revealed three different aggregation iterations at specific length scales. Secondary and higher order aggregate strength was investigated via oscillatory stress rheometry as a means of simulating shear conditions encountered during extrusion. G' and G'' were measured as a function of the applied oscillatory stress. Oscillatory rheometry indicated a strong variation as a function of the sulfate level of the particles in the viscoelastic yield strengths. Powder yield stresses ranged from 3.0 Pa to 24.0 Pa of oscillatory stress. Compaction curves to 750 MPa found strong similarities in extrapolated yield point of stage I and II compaction for each of the powders (at approximately 500 MPa) suggesting that the variation in sulfate was greatest above the primary aggregate level. Scanning electron microscopy of samples at different states of shear in oscillatory rheometry confirmed the variation in the linear elastic region and the viscous flow regime. A technique of this investigation was to approach aggregation via a novel perspective: aggregates are distinguished as being loose open structures that are highly disordered and stochastic in nature. The methodology used was to investigate the shear stresses required to rupture the various aggregation stages encountered and investigate the attempt to realign the now free-flowing constituents comprising the aggregate into a denser configuration. Mercury porosimetry was utilized to measure the pore size of the compact resulting from

  18. An amino-terminal domain of Enterococcus faecalis aggregation substance is required for aggregation, bacterial internalization by epithelial cells and binding to lipoteichoic acid.

    PubMed

    Waters, Christopher M; Hirt, Helmut; McCormick, John K; Schlievert, Patrick M; Wells, Carol L; Dunny, G M

    2004-05-01

    Aggregation substance (AS), a plasmid-encoded surface protein of Enterococcus faecalis, plays important roles in virulence and antibiotic resistance transfer. Previous studies have suggested that AS-mediated aggregation of enterococcal cells could involve the binding of this protein to cell wall lipoteichoic acid (LTA). Here, a method to purify an undegraded form of Asc10, the AS of the plasmid pCF10, is described. Using this purified protein, direct binding of Asc10 to purified E. faecalis LTA was demonstrated. Equivalent binding of Asc10 to LTA purified from INY3000, an E. faecalis strain that is incapable of aggregation, was also observed. Surprisingly, mutations in a previously identified aggregation domain from amino acids 473 to 683 that abolished aggregation had no effect on LTA binding. In frame deletion analysis of Asc10 was used to identify a second aggregation domain located in the N-terminus of the protein from amino acids 156 to 358. A purified Asc10 mutant protein lacking this domain showed reduced LTA binding, while a purified N-terminal fragment from amino acids 44-331 had high LTA binding. Like the previously described aggregation domain, the newly identified Asc10((156-358)) aggregation domain was also required for efficient internalization of E. faecalis into HT-29 enterocytes. Thus, Asc10 possess two distinct domains required for aggregation and eukaryotic cell internalization: an N-terminal domain that promotes binding to LTA and a second domain located near the middle of the protein. PMID:15130132

  19. Carbon mineralization and microbial biomass in soil aggregates from two tillage systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil quality is a concept of many interrelated factors that perform in concert to improve soil productivity. Few of the factors for soil quality are microbial biomass, soil aggregate fractions, and carbon mineralization in different aggregate fractions that are influenced by the agricultural practic...

  20. Monosized aggregates -- A new model

    SciTech Connect

    Gopal, M.

    1997-08-01

    For applications requiring colloidal particles, it is desirable that they be monosized to better control the structure and the properties. In a number of systems, the monosized particles come together to form aggregates that are also monosized. A model is presented here to explain the formation of these monosized aggregates. This is of particular importance in the fields of ceramics, catalysis, pigments, pharmacy, photographic emulsions, etc.

  1. Distinct stress conditions result in aggregation of proteins with similar properties.

    PubMed

    Weids, Alan J; Ibstedt, Sebastian; Tamás, Markus J; Grant, Chris M

    2016-01-01

    Protein aggregation is the abnormal association of proteins into larger aggregate structures which tend to be insoluble. This occurs during normal physiological conditions and in response to age or stress-induced protein misfolding and denaturation. In this present study we have defined the range of proteins that aggregate in yeast cells during normal growth and after exposure to stress conditions including an oxidative stress (hydrogen peroxide), a heavy metal stress (arsenite) and an amino acid analogue (azetidine-2-carboxylic acid). Our data indicate that these three stress conditions, which work by distinct mechanisms, promote the aggregation of similar types of proteins probably by lowering the threshold of protein aggregation. The proteins that aggregate during physiological conditions and stress share several features; however, stress conditions shift the criteria for protein aggregation propensity. This suggests that the proteins in aggregates are intrinsically aggregation-prone, rather than being proteins which are affected in a stress-specific manner. We additionally identified significant overlaps between stress aggregating yeast proteins and proteins that aggregate during ageing in yeast and C. elegans. We suggest that similar mechanisms may apply in disease- and non-disease settings and that the factors and components that control protein aggregation may be evolutionary conserved. PMID:27086931

  2. Distinct stress conditions result in aggregation of proteins with similar properties

    PubMed Central

    Weids, Alan J.; Ibstedt, Sebastian; Tamás, Markus J.; Grant, Chris M.

    2016-01-01

    Protein aggregation is the abnormal association of proteins into larger aggregate structures which tend to be insoluble. This occurs during normal physiological conditions and in response to age or stress-induced protein misfolding and denaturation. In this present study we have defined the range of proteins that aggregate in yeast cells during normal growth and after exposure to stress conditions including an oxidative stress (hydrogen peroxide), a heavy metal stress (arsenite) and an amino acid analogue (azetidine-2-carboxylic acid). Our data indicate that these three stress conditions, which work by distinct mechanisms, promote the aggregation of similar types of proteins probably by lowering the threshold of protein aggregation. The proteins that aggregate during physiological conditions and stress share several features; however, stress conditions shift the criteria for protein aggregation propensity. This suggests that the proteins in aggregates are intrinsically aggregation-prone, rather than being proteins which are affected in a stress-specific manner. We additionally identified significant overlaps between stress aggregating yeast proteins and proteins that aggregate during ageing in yeast and C. elegans. We suggest that similar mechanisms may apply in disease- and non-disease settings and that the factors and components that control protein aggregation may be evolutionary conserved. PMID:27086931

  3. Friction factors and heat transfer coefficients in turbulated cooling passages of different aspect ratios. I - Experimental results

    NASA Astrophysics Data System (ADS)

    Taslim, M. E.; Spring, S. D.

    1987-06-01

    In advanced turbine airfoil cooling designs where multiple-pass cooling circuits are used, a range of cooling passage aspect ratios (height/width) are encountered. The objective of this experimental investigation was to determine the effect that increasing aspect ratios have on friction factors and Nusselt numbers in internal cooling passages with rib-roughened (turbulated) surfaces. Aspect ratios ranging from 0.5 to 3.5 were tested over a Reynolds number range of 30,000 to 190,000. Each aspect ratio was tested at three different turbulator-height/hydraulic-diameter ratios and at a constant turbulator-height/pitch ratio of 0.10.

  4. Model for amorphous aggregation processes

    NASA Astrophysics Data System (ADS)

    Stranks, Samuel D.; Ecroyd, Heath; van Sluyter, Steven; Waters, Elizabeth J.; Carver, John A.; von Smekal, Lorenz

    2009-11-01

    The amorphous aggregation of proteins is associated with many phenomena, ranging from the formation of protein wine haze to the development of cataract in the eye lens and the precipitation of recombinant proteins during their expression and purification. While much literature exists describing models for linear protein aggregation, such as amyloid fibril formation, there are few reports of models which address amorphous aggregation. Here, we propose a model to describe the amorphous aggregation of proteins which is also more widely applicable to other situations where a similar process occurs, such as in the formation of colloids and nanoclusters. As first applications of the model, we have tested it against experimental turbidimetry data of three proteins relevant to the wine industry and biochemistry, namely, thaumatin, a thaumatinlike protein, and α -lactalbumin. The model is very robust and describes amorphous experimental data to a high degree of accuracy. Details about the aggregation process, such as shape parameters of the aggregates and rate constants, can also be extracted.

  5. Glycation precedes lens crystallin aggregation

    SciTech Connect

    Swamy, M.S.; Perry, R.E.; Abraham, E.C.

    1987-05-01

    Non-enzymatic glycosylation (glycation) seems to have the potential to alter the structure of crystallins and make them susceptible to thiol oxidation leading to disulfide-linked high molecular weight (HMW) aggregate formation. They used streptozotocin diabetic rats during precataract and cataract stages and long-term cell-free glycation of bovine lens crystallins to study the relationship between glycation and lens crystallin aggregation. HMW aggregates and other protein components of the water-soluble (WS) and urea-soluble (US) fractions were separated by molecular sieve high performance liquid chromatography. Glycation was estimated by both (/sup 3/H)NaBH/sub 4/ reduction and phenylboronate agarose affinity chromatography. Levels of total glycated protein (GP) in the US fractions were about 2-fold higher than in the WS fractions and there was a linear increase in GP in both WS and US fractions. This increase was parallelled by a corresponding increase in HMW aggregates. Total GP extracted by the affinity method from the US fraction showed a predominance of HMW aggregates and vice versa. Cell-free glycation studies with bovine crystallins confirmed the results of the animals studies. Increasing glycation caused a corresponding increase in protein insolubilization and the insoluble fraction thus formed also contained more glycated protein. It appears that lens protein glycation, HMW aggregate formation, and protein insolubilization are interrelated.

  6. Alteration of red blood cell aggregation during blood storage

    NASA Astrophysics Data System (ADS)

    Lim, Hyun-Jung; Nam, Jeong-Hun; Lee, Byoung-Kwon; Suh, Jang-Soo; Shin, Sehyun

    2011-06-01

    Even though the trade-off between the benefits and risks of blood transfusion has been discussed for the last several decades, it requires further understanding of the rheological changes in stored blood that include the alteration of red blood cell (RBC) aggregation. The RBC aggregation of stored blood in its autologous plasma was monitored through the storage period (35 days). The critical shear stress, as a measure of RBC aggregation, was determined by using a microfluidic aggregometer. Blood was processed into a blood bag containing the anticoagulant CPDA1 and stored at 4°C. It was subjected to assays after zero, seven, 14, and 35 days. The critical shear stress for stored blood did not change up to 14 days of storage but exhibited a significant decrease after 35 days of storage. These results were identical to those of the conventional aggregation index (AI). Also, in the alteration of RBC aggregation for blood storage, the effect of the plasma factor was slightly stronger than that of the cellular factor. Through the present study, the critical shear stress as a new measure of RBC aggregation may help to monitor and control the quality of blood storage.

  7. Folding and Aggregation of Mucin Domains.

    NASA Astrophysics Data System (ADS)

    Urbanc, Brigita; Bansil, Rama; Turner, Bradley

    2007-03-01

    Mucin glycoproteins consist of tandem repeating glycosylated regions flanked by non-repetitive protein domains with little glycosylation. These non-repetitive domains are involved in polymerization of mucin via disulfide bonds and play an important role in the pH dependent gelation of gastric mucin, which is essential to protecting the stomach from autodigestion. We have examined the folding and aggregation of the non-repetitive sequence of von Willebrand factor vWF-C1 domain (67 amino acids) and PGM 2X (242 amino acids) using Discrete Molecular Dynamics (four-bead protein model with hydrogen bonding and amino acid-specific hydrophobic/hydrophilic and electrostatic interactions of side chains). Simulations of vWF C1 show 4-6 β-strands separated by turns/loops with more loops at lower pH. A simulation of several vWF C1 proteins at low pH shows aggregates still with a high content of β-strands and enhanced turn/loop regions. For the PGM 2X simulation the contact map shows several salt bridges enclosing hairpin turns. The implications of these simulations for describing the aggregation/gelation of PGM will be discussed.

  8. Trust-aware recommendation for improving aggregate diversity

    NASA Astrophysics Data System (ADS)

    Liu, Haifeng; Bai, Xiaomei; Yang, Zhuo; Tolba, Amr; Xia, Feng

    2015-10-01

    Recommender systems are becoming increasingly important and prevalent because of the ability of solving information overload. In recent years, researchers are paying increasing attention to aggregate diversity as a key metric beyond accuracy, because improving aggregate recommendation diversity may increase long tails and sales diversity. Trust is often used to improve recommendation accuracy. However, how to utilize trust to improve aggregate recommendation diversity is unexplored. In this paper, we focus on solving this problem and propose a novel trust-aware recommendation method by incorporating time factor into similarity computation. The rationale underlying the proposed method is that, trustees with later creation time of trust relation can bring more diverse items to recommend to their trustors than other trustees with earlier creation time of trust relation. Through relevant experiments on publicly available dataset, we demonstrate that the proposed method outperforms the baseline method in terms of aggregate diversity while maintaining almost the same recall.

  9. Accelerated adhesion of grafted skin by laser-induced stress wave-based gene transfer of hepatocyte growth factor

    NASA Astrophysics Data System (ADS)

    Aizawa, Kazuya; Sato, Shunichi; Terakawa, Mitsuhiro; Saitoh, Daizoh; Tsuda, Hitoshi; Ashida, Hiroshi; Obara, Minoru

    2009-11-01

    Gene therapy using wound healing-associated growth factor gene has received much attention as a new strategy for improving the outcome of tissue transplantation. We delivered plasmid DNA coding for human hepatocyte growth factor (hHGF) to rat free skin grafts by the use of laser-induced stress waves (LISWs); autografting was performed with the grafts. Systematic analysis was conducted to evaluate the adhesion properties of the grafted tissue; angiogenesis, cell proliferation, and reepithelialization were assessed by immunohistochemistry, and reperfusion was measured by laser Doppler imaging as a function of time after grafting. Both the level of angiogenesis on day 3 after grafting and the increased ratio of blood flow on day 4 to that on day 3 were significantly higher than those in five control groups: grafting with hHGF gene injection alone, grafting with control plasmid vector injection alone, grafting with LISW application alone, grafting with LISW application after control plasmid vector injection, and normal grafting. Reepithelialization was almost completed on day 7 even at the center of the graft with LISW application after hHGF gene injection, while it was not for the grafts of the five control groups. These findings demonstrate the validity of our LISW-based HGF gene transfection to accelerate the adhesion of grafted skins.

  10. Ash Aggregates in Proximal Settings

    NASA Astrophysics Data System (ADS)

    Porritt, L. A.; Russell, K.

    2012-12-01

    Ash aggregates are thought to have formed within and been deposited by the eruption column and plume and dilute density currents and their associated ash clouds. Moist, turbulent ash clouds are considered critical to ash aggregate formation by facilitating both collision and adhesion of particles. Consequently, they are most commonly found in distal deposits. Proximal deposits containing ash aggregates are less commonly observed but do occur. Here we describe two occurrences of vent proximal ash aggregate-rich deposits; the first within a kimberlite pipe where coated ash pellets and accretionary lapilli are found within the intra-vent sequence; and the second in a glaciovolcanic setting where cored pellets (armoured lapilli) occur within <1 km of the vent. The deposits within the A418 pipe, Diavik Diamond Mine, Canada, are the residual deposits within the conduit and vent of the volcano and are characterised by an abundance of ash aggregates. Coated ash pellets are dominant but are followed in abundance by ash pellets, accretionary lapilli and rare cored pellets. The coated ash pellets typically range from 1 - 5 mm in diameter and have core to rim ratios of approximately 10:1. The formation and preservation of these aggregates elucidates the style and nature of the explosive phase of kimberlite eruption at A418 (and other pipes?). First, these pyroclasts dictate the intensity of the kimberlite eruption; it must be energetic enough to cause intense fragmentation of the kimberlite to produce a substantial volume of very fine ash (<62 μm). Secondly, the ash aggregates indicate the involvement of moisture coupled with the presence of dilute expanded eruption clouds. The structure and distribution of these deposits throughout the kimberlite conduit demand that aggregation and deposition operate entirely within the confines of the vent; this indicates that aggregation is a rapid process. Ash aggregates within glaciovolcanic sequences are also rarely documented. The

  11. Factors Influencing Adeno-Associated Virus-Mediated Gene Transfer to Human Cystic Fibrosis Airway Epithelial Cells: Comparison with Adenovirus Vectors

    PubMed Central

    Teramoto, S.; Bartlett, J. S.; McCarty, D.; Xiao, X.; Samulski, R. J.; Boucher, R. C.

    1998-01-01

    Adeno-associated virus (AAV) vectors appear promising for use in gene therapy in cystic fibrosis (CF) patients, yet many features of AAV-mediated gene transfer to airway epithelial cells are not well understood. We compared the transduction efficiencies of AAV vectors and adenovirus (Ad) vectors in immortalized cell lines from CF patients and in nasal epithelial primary cultures from normal humans and CF patients. Similar dose-dependent relationships between the vector multiplicities of infection and the efficiencies of lacZ gene transfer were observed. However, levels of transduction for both Ad and recombinant AAV (rAAV) were significantly lower in the airway epithelial cell than in the control cell lines HeLa and HEK 293. Transduction efficiencies differed among cultured epithelial cell types, with poorly differentiated cells transducing more efficiently than well-differentiated cells. A time-dependent increase in gene expression was observed after infection for both vectors. For Ad, but not for AAV, this increase was dependent on prolonged incubation of cells with the vector. Furthermore, for rAAV (but not for rAd), the delay in maximal transduction could be abrogated by wild-type Ad helper infection. Thus, although helper virus is not required for maximal transduction, it increases the kinetics by which this is achieved. Expression of Ad E4 open reading frame 6 or addition of either hydroxyurea or camptothecin resulted in increased AAV transduction, as previously demonstrated for nonairway cells (albeit to lower final levels), suggesting that second-strand synthesis may not be the sole cause of inefficient transduction. Finally, the efficiency of AAV-mediated ex vivo gene transfer to lung cells was similar to that previously described for Ad vectors in that transduction was limited to regions of epithelial injury and preferentially targeted basal-like cells. These studies address the primary factors influencing rAAV infection of human airway cells and should

  12. Factors influencing adeno-associated virus-mediated gene transfer to human cystic fibrosis airway epithelial cells: comparison with adenovirus vectors.

    PubMed

    Teramoto, S; Bartlett, J S; McCarty, D; Xiao, X; Samulski, R J; Boucher, R C

    1998-11-01

    Adeno-associated virus (AAV) vectors appear promising for use in gene therapy in cystic fibrosis (CF) patients, yet many features of AAV-mediated gene transfer to airway epithelial cells are not well understood. We compared the transduction efficiencies of AAV vectors and adenovirus (Ad) vectors in immortalized cell lines from CF patients and in nasal epithelial primary cultures from normal humans and CF patients. Similar dose-dependent relationships between the vector multiplicities of infection and the efficiencies of lacZ gene transfer were observed. However, levels of transduction for both Ad and recombinant AAV (rAAV) were significantly lower in the airway epithelial cell than in the control cell lines HeLa and HEK 293. Transduction efficiencies differed among cultured epithelial cell types, with poorly differentiated cells transducing more efficiently than well-differentiated cells. A time-dependent increase in gene expression was observed after infection for both vectors. For Ad, but not for AAV, this increase was dependent on prolonged incubation of cells with the vector. Furthermore, for rAAV (but not for rAd), the delay in maximal transduction could be abrogated by wild-type Ad helper infection. Thus, although helper virus is not required for maximal transduction, it increases the kinetics by which this is achieved. Expression of Ad E4 open reading frame 6 or addition of either hydroxyurea or camptothecin resulted in increased AAV transduction, as previously demonstrated for nonairway cells (albeit to lower final levels), suggesting that second-strand synthesis may not be the sole cause of inefficient transduction. Finally, the efficiency of AAV-mediated ex vivo gene transfer to lung cells was similar to that previously described for Ad vectors in that transduction was limited to regions of epithelial injury and preferentially targeted basal-like cells. These studies address the primary factors influencing rAAV infection of human airway cells and should

  13. Improved measurement of labile proton concentration-weighted chemical exchange rate (kws) with experimental factor-compensated and T1-normalized quantitative chemical exchange saturation transfer (CEST) MRI

    PubMed Central

    Wu, Renhua; Liu, Charng-Ming; Liu, Philip K; Sun, Phillip Zhe

    2012-01-01

    Chemical exchange saturation transfer (CEST) MRI enables measurement of dilute CEST agents and microenvironment properties such as pH and temperature, holding great promise for in vivo applications. However, because of confounding concomitant RF irradiation and relaxation effects, the CEST-weighted MRI contrast may not fully characterize the underlying CEST phenomenon. We postulated that the accuracy of quantitative CEST MRI could be improved if the experimental factors (labeling efficiency and RF spillover effect) were estimated and taken into account. Specifically, the experimental factor was evaluated as a function of exchange rate and CEST agent concentration ratio, which remained relatively constant for intermediate RF irradiation power levels. Hence, the experimental factors can be calculated based on the reasonably estimated exchange rate and labile proton concentration ratio, which significantly improved quantification. The simulation was confirmed with Creatine phantoms of serially varied concentration titrated to the same pH, whose reverse exchange rate (kws) was found to be linearly correlated with the concentration. In summary, the proposed solution provides simplified yet reasonably accurate quantification of the underlying CEST system, which may help guide the ongoing development of quantitative CEST MRI. PMID:22649044

  14. Familial aggregation of candidate phenotypes for borderline personality disorder.

    PubMed

    Ruocco, Anthony C; Hudson, James I; Zanarini, Mary C; Gunderson, John G

    2015-01-01

    Borderline personality disorder (BPD) and its core Diagnostic and Statistical Manual of Mental Disorders (DSM) factor-analytically derived phenotypes aggregate in families. To potentially inform future conceptualizations of BPD, this study examined the familial aggregation and co-aggregation with BPD of 3 additional candidate phenotypes for BPD psychopathology: anxiousness, aggressiveness, and cognitive dysregulation. Participants included 347 probands (126 with BPD, 128 without BPD, and 93 with major depressive disorder) and 814 parents and siblings of probands. All participants completed diagnostic assessments and scales assessing the candidate phenotypes. The familial aggregation of phenotypes (correlation of level of phenotype between family members), the familial co-aggregation of phenotypes with BPD (correlation of phenotype with BPD between family members), and the within-individual correlation of phenotypes with BPD were assessed. All 3 candidate phenotypes showed high levels of familial aggregation (rs = .14 - .53, ps < .001), the magnitudes of which were comparable with DSM-based core sectors of psychopathology. Anxiousness and cognitive dysregulation showed strong within-individual associations with BPD (rs = .55 and .46, respectively; ps < .001) and substantial familial co-aggregation with BPD (rs = .12 and .13, respectively; ps ≤ .002). In contrast, aggressiveness showed a weak within-individual association with BPD (r = .11, p = .12) and little familial co-aggregation with BPD (r = .05, p = .21). These findings suggest that anxiousness and cognitive dysregulation are promising phenotypes for BPD psychopathology that move beyond factor-analytically based conceptualizations. In contrast, aggressiveness was only weakly related to BPD, suggesting that this phenotype may not represent an essential feature of this disorder. PMID:25046574

  15. [Therapeutic angiogenesis using genetic transfection. An in vitro quantitative and functional study after gene code transfer for vascular endothelial growth factor].

    PubMed

    Zaric, V; Weltin, D; Stephan, D

    2000-08-01

    Vascular endothelial growth factor (VEGF) gene transfer is a new therapeutic approach in clinical situations where insufficient angiogenesis may impair processes that require vessel formation, such as myocardial ischemia or peripheral vascular disease. The feasibility of this strategy was addressed in vitro by (i) optimisation of DNA transfection into cultured cells using a cationic liposome, (ii) study of the transgene production and it's angiogenic properties. An expression plasmid encoding VEGF165 was used to transfect endothelial cells (EAhy-926) in vitro. Different amounts of the cationic liposome were complexed to the plasmid DNA in order to achieve increasing ratios (1/1, 2/1, 3/1, 4/1, 5/1). Maximal gene expression was obtained when the cationic liposome was mixed to plasmid DNA in a 3/1 ratio. Using this optimised liposome/plasmid DNA formulation, VEGF expression measured by ELISA, reached a maximum of 60 ng/mL 24 hours after gene transfer then rapidly decreased. Conditioned media from transfected cells (CMVEGF) significantly increased the proliferation rate of endothelial cells. The maximal mitogenic effect was observed when the cell media was supplemented with 25% of CMVEGF, corresponding to 10 ng/mL of recombinant VEGF. Addition of the VEGF165 peptide into the cell media showed a similar mitogenic effect. The angiogenic property of the transgene was assessed by the demonstration of its ability to stimulate capillary tubes formation in a tridimensional biologic gel. PMID:10989743

  16. Crystal aggregation in kidney stones; a polymer aggregation problem?

    NASA Astrophysics Data System (ADS)

    Wesson, J.; Beshensky, A.; Viswanathan, P.; Zachowicz, W.; Kleinman, J.

    2008-03-01

    Kidney stones most frequently form as aggregates of calcium oxalate monohydrate (COM) crystals with organic layers between them, and the organic layers contain principally proteins. The pathway leading to the formation of these crystal aggregates in affected people has not been identified, but stone forming patients are thought to have a defect in the structure or distribution of urinary proteins, which normally protect against stone formation. We have developed two polyelectrolyte models that will induce COM crystal aggregation in vitro, and both are consistent with possible urinary protein compositions. The first model was based on mixing polyanionic and polycationic proteins, in portions such that the combined protein charge is near zero. The second model was based on reducing the charge density on partially charged polyanionic proteins, specifically Tamm-Horsfall protein, the second most abundant protein in urine. Both models demonstrated polymer phase separation at solution conditions where COM crystal aggregation was observed. Correlation with data from other bulk crystallization measurements suggest that the anionic side chains form critical binding interactions with COM surfaces that are necessary along with the phase separation process to induce COM crystal aggregation.

  17. Determination of nicotine in tobacco with second-order spectra data of charge-transfer complex in ethanol-water binary solvents processed by parallel factor analysis

    NASA Astrophysics Data System (ADS)

    Gao, Shuqin; Liao, Lifu; Xiao, Xilin; Zhao, Zhiyuan; Du, Nan; Du, Jiangfeng

    2010-05-01

    A new spectrophotometric method for the determination of nicotine in mixtures without pre-separation has been proposed. Nicotine could react with 2,4-dinitrophenol through a charge-transfer reaction to form a colored complex. The second-order data from the visible absorption spectra of the complex in a series of ethanol-water binary solvents with various water volume fractions could be expressed as the combination of two bilinear data matrices. With the bilinear model, the second-order spectra data of mixtures containing nicotine and other interferents could be analysed by using second-order calibration algorithms, and the determination of nicotine in the mixtures could be achieved. The algorithm used here was parallel factor analysis. The method has been successfully used to determine nicotine in tobacco samples with satisfactory results.

  18. Pertussis Toxin B-Pentamer Mediates Intercellular Transfer of Membrane Proteins and Lipids

    PubMed Central

    Millen, Scott H.; Schneider, Olivia D.; Miller, William E.; Monaco, John J.; Weiss, Alison A.

    2013-01-01

    Pertussis toxin (PTx) is the major virulence factor of Bordetella pertussis. The enzymatic or active (A) subunit inactivates host G protein coupled receptor (GPCR) signaling pathways. The non-enzymatic binding (B) subunit also mediates biological effects due to lectin-like binding characteristics, including the induction of T cell receptor (TCR) signaling and subsequent down-regulation of chemokine receptor expression. Here we report another activity attributable to PTxB, facilitating transfer of membrane material between mammalian cells. This activity does not require the TCR, and does not require cell-to-cell contact or cellular aggregation. Rather, membrane vesicles are transferred from donor to recipient cells in a toxin-dependent fashion. Membrane transfer occurs in different cell types, including cultured human T cells, CHO cells, and human primary peripheral blood mononuclear cells. Transfer involves both lipid and integral membrane proteins, as evidenced by the transfer of T and B cell-specific receptor molecules to other PBMCs. Interestingly, membrane transfer activity is a property that PTx shares with some, but not all, cell-aggregating lectins that are mitogenic for human T cells, and appears to be related to the ability to bind certain host cell glycolipids. This phenomenon may represent another mechanism by which pertussis toxin disrupts mammalian intra- and inter-cellular signaling. PMID:24019885

  19. Protein Replacement Therapy and Gene Transfer in Canine Models of Hemophilia A, Hemophilia B, von Willebrand Disease, and Factor VII Deficiency

    PubMed Central

    Nichols, Timothy C.; Dillow, Aaron M.; Franck, Helen W.G.; Merricks, Elizabeth P.; Raymer, Robin A.; Bellinger, Dwight A.; Arruda, Valder R.; High, Katherine A.

    2011-01-01

    Dogs with hemophilia A, hemophilia B, von Willebrand disease (VWD), and factor VII deficiency faithfully recapitulate the severe bleeding phenotype that occurs in humans with these disorders. The first rational approach to diagnosing these bleeding disorders became possible with the development of reliable assays in the 1940s through research that used these dogs. For the next 60 years, treatment consisted of replacement of the associated missing or dysfunctional protein, first with plasma-derived products and subsequently with recombinant products. Research has consistently shown that replacement products that are safe and efficacious in these dogs prove to be safe and efficacious in humans. But these highly effective products require repeated administration and are limited in supply and expensive; in addition, plasma-derived products have transmitted bloodborne pathogens. Recombinant proteins have all but eliminated inadvertent transmission of bloodborne pathogens, but the other limitations persist. Thus, gene therapy is an attractive alternative strategy in these monogenic disorders and has been actively pursued since the early 1990s. To date, several modalities of gene transfer in canine hemophilia have proven to be safe, produced easily detectable levels of transgene products in plasma that have persisted for years in association with reduced bleeding, and correctly predicted the vector dose required in a human hemophilia B liver-based trial. Very recently, however, researchers have identified an immune response to adeno-associated viral gene transfer vector capsid proteins in a human liver-based trial that was not present in preclinical testing in rodents, dogs, or nonhuman primates. This article provides a review of the strengths and limitations of canine hemophilia, VWD, and factor VII deficiency models and of their historical and current role in the development of improved therapy for humans with these inherited bleeding disorders. PMID:19293459

  20. A Method of Data Aggregation for Wearable Sensor Systems.

    PubMed

    Shen, Bo; Fu, Jun-Song

    2016-01-01

    Data aggregation has been considered as an effective way to decrease the data to be transferred in sensor networks. Particularly for wearable sensor systems, smaller battery has less energy, which makes energy conservation in data transmission more important. Nevertheless, wearable sensor systems usually have features like frequently dynamic changes of topologies and data over a large range, of which current aggregating methods can't adapt to the demand. In this paper, we study the system composed of many wearable devices with sensors, such as the network of a tactical unit, and introduce an energy consumption-balanced method of data aggregation, named LDA-RT. In the proposed method, we develop a query algorithm based on the idea of 'happened-before' to construct a dynamic and energy-balancing routing tree. We also present a distributed data aggregating and sorting algorithm to execute top-k query and decrease the data that must be transferred among wearable devices. Combining these algorithms, LDA-RT tries to balance the energy consumptions for prolonging the lifetime of wearable sensor systems. Results of evaluation indicate that LDA-RT performs well in constructing routing trees and energy balances. It also outperforms the filter-based top-k monitoring approach in energy consumption, load balance, and the network's lifetime, especially for highly dynamic data sources. PMID:27347953

  1. A Method of Data Aggregation for Wearable Sensor Systems

    PubMed Central

    Shen, Bo; Fu, Jun-Song

    2016-01-01

    Data aggregation has been considered as an effective way to decrease the data to be transferred in sensor networks. Particularly for wearable sensor systems, smaller battery has less energy, which makes energy conservation in data transmission more important. Nevertheless, wearable sensor systems usually have features like frequently dynamic changes of topologies and data over a large range, of which current aggregating methods can’t adapt to the demand. In this paper, we study the system composed of many wearable devices with sensors, such as the network of a tactical unit, and introduce an energy consumption-balanced method of data aggregation, named LDA-RT. In the proposed method, we develop a query algorithm based on the idea of ‘happened-before’ to construct a dynamic and energy-balancing routing tree. We also present a distributed data aggregating and sorting algorithm to execute top-k query and decrease the data that must be transferred among wearable devices. Combining these algorithms, LDA-RT tries to balance the energy consumptions for prolonging the lifetime of wearable sensor systems. Results of evaluation indicate that LDA-RT performs well in constructing routing trees and energy balances. It also outperforms the filter-based top-k monitoring approach in energy consumption, load balance, and the network’s lifetime, especially for highly dynamic data sources. PMID:27347953

  2. Aggregate stability in citrus plantations. The impact of drip irrigation

    NASA Astrophysics Data System (ADS)

    Cerdà, A.; Mataix-Solera, J.; Arcenegui, V.

    2012-04-01

    Soil aggregate stability is a key property for soil and water conservation, and a synthetic parameter to quantify the soil degradation. Aggregation is relevant in soils where vegetation cover is scarce (Cerdà, 1996). Most of the research carried out to determine the soil aggregate stability was done in forest soils (Mataix-Solera et al., 2011) and little is done on farms (Cerdà, 2000). The research have show the effect of vegetation cover on soil aggregate stability (Cerdà, 1998) but little is known when vegetation is scarce, rare or not found such it can be seeing in agriculture soils. Then, aggregation is the main factor to control the soil losses and to improve the water availability. Moreover, agriculture management can improve the soil aggregate characteristics and the first step in this direction should be to quantify the aggregate stability. There is no information about the aggregate stability of soils under citrus production, although the research did show that the soil losses in the farms with citrus plantations is very high (Cerdà et al., 2009), and that aggregation should play a key role as the soils are bare due to the widespread use of herbicides. From 2009 to 2011, samples were collected in summer and winter in a chemically managed farm in Montesa, Eastern Iberian Peninsula. Ten irrigated patches and ten non-irrigated patches were selected to compare the effect of the drip irrigation on the soil aggregate stability. The Ten Drop Impacts (TDI) and the Counting the number of drops (CND) tests were applied at 200 aggregates (10 samples x 10 aggregates x 2 sites) in winter and summer in 2009, 2010 and 2011. The results show that the irrigated patches had TDI values that ranged from 43 to 56 % and that the non-irrigated reached values of 41 to 54 %. The CND samples ranged from 29 to 38 drops in the non-irrigated patches to 32 to 42 drop-impacts in the irrigated soil patches. No trends were found from winter to summer during the three years time period

  3. Fractal Aggregates in Tennis Ball Systems

    ERIC Educational Resources Information Center

    Sabin, J.; Bandin, M.; Prieto, G.; Sarmiento, F.

    2009-01-01

    We present a new practical exercise to explain the mechanisms of aggregation of some colloids which are otherwise not easy to understand. We have used tennis balls to simulate, in a visual way, the aggregation of colloids under reaction-limited colloid aggregation (RLCA) and diffusion-limited colloid aggregation (DLCA) regimes. We have used the…

  4. Accelerated adhesion of grafted skins by laser-induced stress wave-based gene transfer of hepatocyte growth factor

    NASA Astrophysics Data System (ADS)

    Aizawa, Kazuya; Sato, Shunichi; Saitoh, Daizoh; Tsuda, Hitoshi; Ashida, Hiroshi; Obara, Minoru

    2009-02-01

    In our previous study, we delivered plasmid DNA coding for human hepatocyto growth factor (hHGF) to rat skin grafts based on laser-induced stress wave (LISW), by which production of CD31-positive cells in the grafted skins was found to be enhanced, suggesting improved angiogenesis. In this study, we validated the efficacy of this method to accelerate adhesion of grafted skins; reperfusion and reepithelialization in the grafted skins were examined. As a graft, dorsal skin of a rat was exsected and its subcutaneous fat was removed. Plasmid DNA expression vector for hHGF was injected into the graft; on its back surface a laser target with a transparent sheet for plasma confinement was placed, and irradiated with three nanosecond laser pulses at a laser fluence of 1.2 J/cm2 (532 nm; spot diameter, 3 mm) to generate LISWs. After the application of LISWs, the graft was transplanted onto its donor site. We evaluated blood flow by laser Doppler imaging and analyzed reepithelialization based on immunohistochemistry as a function of postgrafting time. It was found that both reperfusion and reepithelialization were significantly enhanced for the grafts with gene transfection than for normal grafts; reepithelialization was completed within 7 days after transplantation with the transfected grafts. These findings demonstrate that adhesion of grafted skins can be accelerated by delivering HGF gene to the grafts based on LISWs.

  5. Non-viral liposome-mediated transfer of brain-derived neurotrophic factor across the blood-brain barrier

    PubMed Central

    Xing, Ying; Wen, Chun-yan; Li, Song-tao; Xia, Zong-xin

    2016-01-01

    Brain-derived neurotrophic factor (BDNF) plays an important role in the repair of central nervous system injury, but cannot directly traverse the blood-brain barrier. Liposomes are a new type of non-viral vector, able to carry macromolecules across the blood-brain barrier and into the brain. Here, we investigate whether BDNF could be transported across the blood-brain barrier by tail-vein injection of liposomes conjugated to transferrin (Tf) and polyethylene glycol (PEG), and carrying BDNF modified with cytomegalovirus promoter (pCMV) or glial fibrillary acidic protein promoter (pGFAP) (Tf-pCMV-BDNF-PEG and Tf-pGFAP-BDNF-PEG, respectively). Both liposomes were able to traverse the blood-brain barrier, and BDNF was mainly expressed in the cerebral cortex. BDNF expression in the cerebral cortex was higher in the Tf-pGFAP-BDNF-PEG group than in the Tf-pCMV-BDNF-PEG group. This study demonstrates the successful construction of a non-virus targeted liposome, Tf-pGFAP-BDNF-PEG, which crosses the blood-brain barrier and is distributed in the cerebral cortex. Our work provides an experimental basis for BDNF-related targeted drug delivery in the brain. PMID:27212923

  6. Increased encapsulated cell biodelivery of nerve growth factor in the brain by transposon-mediated gene transfer.

    PubMed

    Fjord-Larsen, L; Kusk, P; Emerich, D F; Thanos, C; Torp, M; Bintz, B; Tornøe, J; Johnsen, A H; Wahlberg, L U

    2012-10-01

    Nerve growth factor (NGF) is a potential therapeutic agent for Alzheimer's disease (AD) as it has positive effects on the basal forebrain cholinergic neurons whose degeneration correlates with the cognitive decline in AD. We have previously described an encapsulated cell biodelivery device, NsG0202, capable of local delivery of NGF by a genetically modified human cell line, NGC-0295. The NsG0202 devices have shown promising safety and therapeutic results in a small phase 1b clinical study. However, results also show that the NGF dose could advantageously be increased. We have used the sleeping beauty transposon expression technology to establish a new clinical grade cell line, NGC0211, with at least 10 times higher NGF production than that of NGC-0295. To test whether encapsulation of this cell line provides a relevant dose escalation step in delivering NGF for treatment of the cognitive decline in AD patients, we have validated the bioactivity of devices with NGC0211 and NGC-0295 cells in normal rat striatum as well as in the quinolinic acid striatal lesion model. These preclinical animal studies show that implantation of devices with NGC0211 cells lead to significantly higher NGF output, which in both cases correlate with highly improved potency. PMID:22113314

  7. A gene transfer comparative study of HSA-conjugated antiangiogenic factors in a transgenic mouse model of metastatic ocular cancer.

    PubMed

    Frau, E; Magnon, C; Opolon, P; Connault, E; Opolon, D; Beermann, F; Beerman, F; Abitbol, M; Perricaudet, M; Bouquet, C

    2007-03-01

    Different antiangiogenic and antimetastatic recombinant adenoviruses were tested in a transgenic mouse model of metastatic ocular cancer (TRP1/SV40 Tag transgenic mice), which is a highly aggressive tumor, developed from the pigmented epithelium of the retina. These vectors, encoding amino-terminal fragments of urokinase plasminogen activator (ATF), angiostatin Kringles (K1-3), endostatin (ES) and canstatin (Can) coupled to human serum albumin (HSA) were injected to assess their metastatic and antiangiogenic activities in our model. Compared to AdCO1 control group, AdATF-HSA did not significantly reduce metastatic growth. In contrast, mice treated with AdK1-3-HSA, AdES-HSA and AdCan-HSA displayed significantly smaller metastases (1.19+/-1.19, 0.87+/-1.5, 0.43+/-0.56 vs controls 4.04+/-5.12 mm3). Moreover, a stronger inhibition of metastatic growth was obtained with AdCan-HSA than with AdK1-3-HSA (P=0.04). Median survival was improved by 4 weeks. A close correlation was observed between the effects of these viruses on metastatic growth and their capacity to inhibit tumor angiogenesis. Our study indicates that systemic antiangiogenic factors production by recombinant adenoviruses, particularly Can, might represent an effective way of delaying metastatic growth via inhibition of angiogenesis. PMID:17082795

  8. Enhancement of innate immune system in monocot rice by transferring the dicotyledonous elongation factor Tu receptor EFR.

    PubMed

    Lu, Fen; Wang, Huiqin; Wang, Shanzhi; Jiang, Wendi; Shan, Changlin; Li, Bin; Yang, Jun; Zhang, Shiyong; Sun, Wenxian

    2015-07-01

    The elongation factor Tu (EF-Tu) receptor (EFR) in cruciferous plants specifically recognizes the N-terminal acetylated elf18 region of bacterial EF-Tu and thereby activates plant immunity. It has been demonstrated that Arabidopsis EFR confers broad-spectrum bacterial resistance in the EFR transgenic solanaceous plants. Here, the transgenic rice plants (Oryza sativa L. ssp. japonica cv. Zhonghua 17) and cell cultures with constitutive expression of AtEFR were developed to investigate whether AtEFR senses EF-Tu and thus enhances bacterial resistance in the monocot plants. We demonstrated that the Xanthomonas oryzae-derived elf18 peptide induced oxidative burst and mitogen-activated protein kinase activation in the AtEFR transgenic rice cells and plants, respectively. Pathogenesis-related genes, such as OsPBZ1, were upregulated dramatically in transgenic rice plant and cell lines in response to elf18 stimulation. Importantly, pretreatment with elf18 triggered strong resistance to X. oryzae pv. oryzae in the transgenic plants, which was largely dependent on the AtEFR expression level. These plants also exhibited enhanced resistance to rice bacterial brown stripe, but not to rice fungal blast. Collectively, the results indicate that the rice plants with heterologous expression of AtEFR recognize bacterial EF-Tu and exhibit enhanced broad-spectrum bacterial disease resistance and that pattern recognition receptor-mediated immunity may be manipulated across the two plant classes, dicots and monocots. PMID:25358295

  9. Non-viral liposome-mediated transfer of brain-derived neurotrophic factor across the blood-brain barrier.

    PubMed

    Xing, Ying; Wen, Chun-Yan; Li, Song-Tao; Xia, Zong-Xin

    2016-04-01

    Brain-derived neurotrophic factor (BDNF) plays an important role in the repair of central nervous system injury, but cannot directly traverse the blood-brain barrier. Liposomes are a new type of non-viral vector, able to carry macromolecules across the blood-brain barrier and into the brain. Here, we investigate whether BDNF could be transported across the blood-brain barrier by tail-vein injection of liposomes conjugated to transferrin (Tf) and polyethylene glycol (PEG), and carrying BDNF modified with cytomegalovirus promoter (pCMV) or glial fibrillary acidic protein promoter (pGFAP) (Tf-pCMV-BDNF-PEG and Tf-pGFAP-BDNF-PEG, respectively). Both liposomes were able to traverse the blood-brain barrier, and BDNF was mainly expressed in the cerebral cortex. BDNF expression in the cerebral cortex was higher in the Tf-pGFAP-BDNF-PEG group than in the Tf-pCMV-BDNF-PEG group. This study demonstrates the successful construction of a non-virus targeted liposome, Tf-pGFAP-BDNF-PEG, which crosses the blood-brain barrier and is distributed in the cerebral cortex. Our work provides an experimental basis for BDNF-related targeted drug delivery in the brain. PMID:27212923

  10. Neonatal transfer of membrane-bound stem cell factor improves survival and heart function in aged mice after myocardial ischemia.

    PubMed

    Sun, Zhuo; Lee, Chyan-Jang; Mejia-Guerrero, Salvador; Zhang, Yuemei; Higuchi, Koji; Li, Ren-Ke; Medin, Jeffrey A

    2012-12-01

    Stem cell mobilization to injured tissue contributes to neovascularization, resulting in regeneration after myocardial infarction (MI). We previously showed that direct cardiac injection of a recombinant lentivirus (LV) that engineers expression of membrane-bound stem cell factor (mSCF) improves outcomes immediately after MI. In this study, we evaluated the effect of neonatal LV/mSCF transduction on MI outcomes in aged mice. We constructed a recombinant LV harboring an α-myosin heavy chain promoter that drives mSCF expression and injected it into the temporal vein of neonatal mice. One year later, sustained expression of mSCF in the adult mouse hearts was detected by genomic and quantitative RT-PCR and immunohistochemistry. To evaluate the contribution of neonatal LV/mSCF delivery to recovery from MI, we induced an MI in adult LV/mSCF-transduced, LV only-transduced, and nontransduced control mice. Strikingly, LV/mSCF transduction reduced infarct scar size, enhanced angiogenesis, improved ventricular function, and significantly increased survival of the mice. Regional overexpression of CD11b, a marker of monocytes and proangiogenic cells, was observed on monocytes isolated from the infarcted hearts of LV/mSCF-transduced mice. Our data suggest a model of neonatal gene delivery that leads to sustained mSCF expression during adulthood to aid recovery from MI and prevent heart failure. PMID:22998370

  11. Aggregation behavior of a tetrameric cationic surfactant in aqueous solution.

    PubMed

    Hou, Yanbo; Han, Yuchun; Deng, Manli; Xiang, Junfen; Wang, Yilin

    2010-01-01

    A star-shaped tetrameric quaternary ammonium surfactant PATC, which has four hydrophobic chains and charged hydrophilic headgroups connected by amide-type spacer group, has been synthesized in this work. Surface tension, electrical conductivity, ITC, DLS, and NMR have been used to investigate the relationship between its chemical structure and its aggregation properties. Interestingly, a large size distribution around 75 nm is observed below the critical micelle concentration (cmc) of PATC, and the large size distribution starts to decrease beyond the cmc and finally transfers to a small size distribution. It is proved that the large size premicellar aggregates may display network-like structure, and the size decrease beyond the cmc is the transition of the network-like aggregates to micelles. The possible reason is that intramolecular electrostatic repulsion among the charged headgroups below the cmc leads to a star-shaped molecular configuration, which may form the network-like aggregates through intermolecular hydrophobic interaction between hydrocarbon chains, while the hydrophobic effect becomes strong enough to turn the molecular configuration into pyramid-like shape beyond the cmc, which make the transition of network-like aggregates to micelles available. PMID:19947615

  12. Fast Triplet Formation via Singlet Exciton Fission in a Covalent Perylenediimide-β-apocarotene Dyad Aggregate.

    PubMed

    Mauck, Catherine M; Brown, Kristen E; Horwitz, Noah E; Wasielewski, Michael R

    2015-06-01

    A covalent dyad was synthesized in which perylene-3,4,:9:10-bis(dicarboximide) (PDI) is linked to β-apocarotene (Car) using a biphenyl spacer. The dyad is monomeric in toluene and forms a solution aggregate in methylcyclohexane (MCH). Using femtosecond transient absorption (fsTA) spectroscopy, the monomeric dyad and its aggregates were studied both in solution and in thin films. In toluene, photoexcitation at 530 nm preferentially excites PDI, and the dyad undergoes charge separation in τ = 1.7 ps and recombination in τ = 1.6 ns. In MCH and in thin solid films, 530 nm excitation of the PDI-Car aggregate also results in charge transfer that competes with energy transfer from (1)*PDI to Car and with an additional process, rapid Car triplet formation in <50 ps. Car triplet formation is only observed in the aggregated PDI-Car dyad and is attributed to singlet exciton fission (SF) within the aggregated PDI, followed by rapid triplet energy transfer from (3)*PDI to the carotenoid. SF from β-apocarotene aggregation is ruled out by direct excitation of Car films at 414 nm, where no triplet formation is observed. Time-resolved electron paramagnetic resonance measurements on aggregated PDI-Car show the formation of (3)*Car with a spin-polarization pattern that rules out radical-pair intersystem crossing as the mechanism of triplet formation as well. PMID:25961130

  13. Aggregated Recommendation through Random Forests

    PubMed Central

    2014-01-01

    Aggregated recommendation refers to the process of suggesting one kind of items to a group of users. Compared to user-oriented or item-oriented approaches, it is more general and, therefore, more appropriate for cold-start recommendation. In this paper, we propose a random forest approach to create aggregated recommender systems. The approach is used to predict the rating of a group of users to a kind of items. In the preprocessing stage, we merge user, item, and rating information to construct an aggregated decision table, where rating information serves as the decision attribute. We also model the data conversion process corresponding to the new user, new item, and both new problems. In the training stage, a forest is built for the aggregated training set, where each leaf is assigned a distribution of discrete rating. In the testing stage, we present four predicting approaches to compute evaluation values based on the distribution of each tree. Experiments results on the well-known MovieLens dataset show that the aggregated approach maintains an acceptable level of accuracy. PMID:25180204

  14. Aggregated recommendation through random forests.

    PubMed

    Zhang, Heng-Ru; Min, Fan; He, Xu

    2014-01-01

    Aggregated recommendation refers to the process of suggesting one kind of items to a group of users. Compared to user-oriented or item-oriented approaches, it is more general and, therefore, more appropriate for cold-start recommendation. In this paper, we propose a random forest approach to create aggregated recommender systems. The approach is used to predict the rating of a group of users to a kind of items. In the preprocessing stage, we merge user, item, and rating information to construct an aggregated decision table, where rating information serves as the decision attribute. We also model the data conversion process corresponding to the new user, new item, and both new problems. In the training stage, a forest is built for the aggregated training set, where each leaf is assigned a distribution of discrete rating. In the testing stage, we present four predicting approaches to compute evaluation values based on the distribution of each tree. Experiments results on the well-known MovieLens dataset show that the aggregated approach maintains an acceptable level of accuracy. PMID:25180204

  15. Hydraulic and mechanical properties of soil aggregates under organic and conventional soil management

    NASA Astrophysics Data System (ADS)

    Wójciga, A.; Kuś, J.; Turski, M.; Lipiec, J.

    2009-04-01

    Variation in hydraulic and mechanical properties of soil aggregates is an important factor affecting water storage and infiltration because the large inter-aggregate pores are dewatered first and the transport of water and solutes is influenced by the properties of the individual aggregates and contacts between them. A high mechanical stability of soil aggregates is fundamental for the maintenance of proper tilth and provides stable traction for farm implements, but limit root growth inside aggregates. The aggregate properties are largely influenced by soil management practices. Our objective was to compare the effects of organic and conventional soil management on hydraulic and mechanical properties of soil aggregates. Experimental fields subjected to long-term organic (14 years) and conventional managements were located on loamy soil at the Institute of Soil Science and Plant Cultivation - National Research Institute in Pulawy, Poland. Soil samples were collected from two soil depths (0-10 cm and 10-20 cm). After air-drying, two size fractions of soil aggregates (15-20 and 30-35 mm) were manually selected and kept in the dried state in a dessicator in order to provide the same boundary conditions. Following properties of the aggregates were determined: porosity (%) using standard wax method, cumulative infiltration Q (mm3 s-1) and sorptivity S (mm s -1/2) of water and ethanol using a tube with a sponge inserted at the tip, wettability (by comparison of sorptivity of water and ethanol) using repellency index R, crushing strength q (MPa) using strength testing device (Zwick/Roell) and calculated by Dexter's formula. All properties were determined in 15 replicates for each treatment, aggregates size and depth. Organic management decreased porosity of soil aggregates and ethanol infiltration. All aggregates revealed rather limited wettability (high repellency index). In most cases the aggregate wettability was lower under conventional than organic soil management

  16. Aggregation operations for multiaspect fuzzy soft sets

    NASA Astrophysics Data System (ADS)

    Sulaiman, Nor Hashimah; Mohamad, Daud

    2015-10-01

    Multiaspect fuzzy soft set (MAFSS) is one of the generalized forms of fuzzy soft sets. In this paper, we introduce two types of aggregation operations for MAFSSs, namely the weighted arithmetic mean (WAM)-based MAFSS aggregation, and the ordered weighted aggregation (OWA)-based MAFSS aggregation. The applicability of the two MAFSS-aggregation operations is illustrated with numerical examples in group decision making.

  17. Evaporation effects in elastocapillary aggregation

    NASA Astrophysics Data System (ADS)

    Vella, Dominic; Hadjittofis, Andreas; Singh, Kiran; Lister, John

    2015-11-01

    We consider the effect of evaporation on the aggregation of a number of elastic objects due to a liquid's surface tension. In particular, we consider an array of spring-block elements in which the gaps between blocks are filled by thin liquid films that evaporate during the course of an experiment. Using lubrication theory to account for the fluid flow within the gaps, we study the dynamics of aggregation. We find that a non-zero evaporation rate causes the elements to aggregate more quickly and, indeed, to contact within finite time. However, we also show that the number of elements within each cluster decreases as the evaporation rate increases. We explain these results quantitatively by comparison with the corresponding two-body problem and discuss their relevance for controlling pattern formation in carbon nanotube forests.

  18. Molecular Aggregation in Disodium Cromoglycate

    NASA Astrophysics Data System (ADS)

    Singh, Gautam; Agra-Kooijman, D.; Collings, P. J.; Kumar, Satyendra

    2012-02-01

    Details of molecular aggregation in the mesophases of the anti-asthmatic drug disodium cromoglycate (DSCG) have been studied using x-ray synchrotron scattering. The results show two reflections, one at wide angles corresponding to π-π stacking (3.32 å) of molecules, and the other at small angles which is perpendicular to the direction of molecular stacking and corresponds to the distance between the molecular aggregates. The latter varies from 35 - 41 å in the nematic (N) phase and 27 -- 32 å in the columnar (M) phase. The temperature evolution of the stack height, positional order correlations in the lateral direction, and orientation order parameter were determined in the N, M, and biphasic regions. The structure of the N and M phases and the nature of the molecular aggregation, together with their dependence on temperature and concentration, will be presented.

  19. An experimental study of dense aerosol aggregations

    NASA Astrophysics Data System (ADS)

    Dhaubhadel, Rajan

    We demonstrated that an aerosol can gel. This gelation was then used for a one-step method to produce an ultralow density porous carbon or silica material. This material was named an aerosol gel because it was made via gelation of particles in the aerosol phase. The carbon and silica aerosol gels had high specific surface area (200--350 sq m2/g for carbon and 300--500 sq m2/g for silica) and an extremely low density (2.5--6.0 mg/cm3), properties similar to conventional aerogels. Key aspects to form a gel from an aerosol are large volume fraction, ca. 10-4 or greater, and small primary particle size, 50 nm or smaller, so that the gel time is fast compared to other characteristic times. Next we report the results of a study of the cluster morphology and kinetics of a dense aggregating aerosol system using the small angle light scattering technique. The soot particles started as individual monomers, ca. 38 nm radius, grew to bigger clusters with time and finally stopped evolving after spanning a network across the whole system volume. This spanning is aerosol gelation. The gelled system showed a hybrid morphology with a lower fractal dimension at length scales of a micron or smaller and a higher fractal dimension at length scales greater than a micron. The study of the kinetics of the aggregating system showed that when the system gelled, the aggregation kernel homogeneity lambda attained a value 0.4 or higher. The magnitude of the aggregation kernel showed an increase with increasing volume fraction. We also used image analysis technique to study the cluster morphology. From the digitized pictures of soot clusters the cluster morphology was determined by two different methods: structure factor and perimeter analysis. We find a hybrid, superaggregate morphology characterized by a fractal dimension of Df ≈ to 1.8 between the monomer size, ca. 50 nm, and 1 mum micron and Df ≈ to 2.6 at larger length scales up to ˜ 10 mum. The superaggregate morphology is a

  20. Cell-to-cell propagation of infectious cytosolic protein aggregates

    PubMed Central

    Hofmann, Julia P.; Denner, Philip; Nussbaum-Krammer, Carmen; Kuhn, Peer-Hendrik; Suhre, Michael H.; Scheibel, Thomas; Lichtenthaler, Stefan F.; Schätzl, Hermann M.; Bano, Daniele; Vorberg, Ina M.

    2013-01-01

    Prions are self-templating protein conformers that replicate by recruitment and conversion of homotypic proteins into growing protein aggregates. Originally identified as causative agents of transmissible spongiform encephalopathies, increasing evidence now suggests that prion-like phenomena are more common in nature than previously anticipated. In contrast to fungal prions that replicate in the cytoplasm, propagation of mammalian prions derived from the precursor protein PrP is confined to the cell membrane or endocytic vesicles. Here we demonstrate that cytosolic protein aggregates can also behave as infectious entities in mammalian cells. When expressed in the mammalian cytosol, protein aggregates derived from the prion domain NM of yeast translation termination factor Sup35 persistently propagate and invade neighboring cells, thereby inducing a self-perpetuating aggregation state of NM. Cell contact is required for efficient infection. Aggregates can also be induced in primary astrocytes, neurons, and organotypic cultures, demonstrating that this phenomenon is not specific to immortalized cells. Our data have important implications for understanding prion-like phenomena of protein aggregates associated with human diseases and for the growing number of amyloidogenic proteins discovered in mammals. PMID:23509289

  1. Electrically conductive bulk composites through a contact-connected aggregate.

    PubMed

    Nawroj, Ahsan I; Swensen, John P; Dollar, Aaron M

    2013-01-01

    This paper introduces a concept that allows the creation of low-resistance composites using a network of compliant conductive aggregate units, connected through contact, embedded within the composite. Due to the straight-forward fabrication method of the aggregate, conductive composites can be created in nearly arbitrary shapes and sizes, with a lower bound near the length scale of the conductive cell used in the aggregate. The described instantiation involves aggregate cells that are approximately spherical copper coils-of-coils within a polymeric matrix, but the concept can be implemented with a wide range of conductor elements, cell geometries, and matrix materials due to its lack of reliance on specific material chemistries. The aggregate cell network provides a conductive pathway that can have orders of magnitude lower resistance than that of the matrix material--from 10(12) ohm-cm (approx.) for pure silicone rubber to as low as 1 ohm-cm for the silicone/copper composite at room temperature for the presented example. After describing the basic concept and key factors involved in its success, three methods of implementing the aggregate into a matrix are then addressed--unjammed packing, jammed packing, and pre-stressed jammed packing--with an analysis of the tradeoffs between increased stiffness and improved resistivity. PMID:24349239

  2. An in vivo platform for identifying inhibitors of protein aggregation

    PubMed Central

    Mahood, Rachel A.; Jackson, Matthew P.; Revill, Charlotte H.; Foster, Richard J.; Smith, D. Alastair; Ashcroft, Alison E.; Brockwell, David J.; Radford, Sheena E.

    2015-01-01

    Protein aggregation underlies an array of human diseases, yet only one small molecule therapeutic has been successfully developed to date. Here, we introduce an in vivo system, based on a β-lactamase tripartite fusion construct, capable of identifying aggregation-prone sequences in the periplasm of Escherichia coli and inhibitors that prevent their aberrant self-assembly. We demonstrate the power of the system using a range of proteins, from small unstructured peptides (islet amyloid polypeptide and amyloid β) to larger, folded immunoglobulin domains. Configured in a 48-well format, the split β-lactamase sensor readily differentiates between aggregation-prone and soluble sequences. Performing the assay in the presence of 109 compounds enabled a rank ordering of inhibition and revealed a new inhibitor of IAPP aggregation. This platform can be applied to both amyloidogenic and other aggregation-prone systems, independent of sequence or size, and can identify small molecules or other factors able to ameliorate or inhibit protein aggregation. PMID:26656088

  3. An in vivo platform for identifying inhibitors of protein aggregation.

    PubMed

    Saunders, Janet C; Young, Lydia M; Mahood, Rachel A; Jackson, Matthew P; Revill, Charlotte H; Foster, Richard J; Smith, D Alastair; Ashcroft, Alison E; Brockwell, David J; Radford, Sheena E

    2016-02-01

    Protein aggregation underlies an array of human diseases, yet only one small-molecule therapeutic targeting this process has been successfully developed to date. Here, we introduce an in vivo system, based on a β-lactamase tripartite fusion construct, that is capable of identifying aggregation-prone sequences in the periplasm of Escherichia coli and inhibitors that prevent their aberrant self-assembly. We demonstrate the power of the system using a range of proteins, from small unstructured peptides (islet amyloid polypeptide and amyloid β) to larger, folded immunoglobulin domains. Configured in a 48-well format, the split β-lactamase sensor readily differentiates between aggregation-prone and soluble sequences. Performing the assay in the presence of 109 compounds enabled a rank ordering of inhibition and revealed a new inhibitor of islet amyloid polypeptide aggregation. This platform can be applied to both amyloidogenic and other aggregation-prone systems, independent of sequence or size, and can identify small molecules or other factors able to ameliorate or inhibit protein aggregation. PMID:26656088

  4. Electrically Conductive Bulk Composites through a Contact-Connected Aggregate

    PubMed Central

    Nawroj, Ahsan I.; Swensen, John P.; Dollar, Aaron M.

    2013-01-01

    This paper introduces a concept that allows the creation of low-resistance composites using a network of compliant conductive aggregate units, connected through contact, embedded within the composite. Due to the straight-forward fabrication method of the aggregate, conductive composites can be created in nearly arbitrary shapes and sizes, with a lower bound near the length scale of the conductive cell used in the aggregate. The described instantiation involves aggregate cells that are approximately spherical copper coils-of-coils within a polymeric matrix, but the concept can be implemented with a wide range of conductor elements, cell geometries, and matrix materials due to its lack of reliance on specific material chemistries. The aggregate cell network provides a conductive pathway that can have orders of magnitude lower resistance than that of the matrix material - from 1012 ohm-cm (approx.) for pure silicone rubber to as low as 1 ohm-cm for the silicone/copper composite at room temperature for the presented example. After describing the basic concept and key factors involved in its success, three methods of implementing the aggregate into a matrix are then addressed – unjammed packing, jammed packing, and pre-stressed jammed packing – with an analysis of the tradeoffs between increased stiffness and improved resistivity. PMID:24349239

  5. Production of transgenic goats expressing human coagulation factor IX in the mammary glands after nuclear transfer using transfected fetal fibroblast cells.

    PubMed

    Amiri Yekta, Amir; Dalman, Azam; Eftekhari-Yazdi, Poopak; Sanati, Mohammad Hossein; Shahverdi, Abdol Hossein; Fakheri, Rahman; Vazirinasab, Hamed; Daneshzadeh, Mohammad Taghi; Vojgani, Mahdi; Zomorodipour, Alireza; Fatemi, Nayeralsadat; Vahabi, Zeinab; Mirshahvaladi, Shahab; Ataei, Fariba; Bahraminejad, Elmira; Masoudi, Najmehsadat; Rezazadeh Valojerdi, Mojtaba; Gourabi, Hamid

    2013-02-01

    There are growing numbers of recombinant proteins that have been expressed in milk. Thus one can consider the placement of any gene of interest under the control of the regulatory elements of a milk protein gene in a dairy farm animal. Among the transgene introducing techniques, only nuclear transfer (NT) allows 100 % efficiency and bypasses the mosaicism associated with counterpart techniques. In this study, in an attempt to produce a transgenic goat carrying the human coagulation factor IX (hFIX) transgene, goat fetal fibroblasts were electroporated with a linearized marker-free construct in which the transgene was juxtaposed to β-casein promoter designed to secret the recombinant protein in goat milk. Two different lines of transfected cells were used as donors for NT to enucleated oocytes. Two transgenic goats were liveborn. DNA sequencing of the corresponding transgene locus confirmed authenticity of the cloning procedure and the complementary experiments on the whey demonstrated expression of human factor IX in the milk of transgenic goats. In conclusion, our study has provided the groundwork for a prosperous and promising approach for large-scale production and therapeutic application of hFIX expressed in transgenic goats. PMID:22869287

  6. Sites Involved in Intra- and Interdomain Allostery Associated with the Activation of Factor VIIa Pinpointed by Hydrogen-Deuterium Exchange and Electron Transfer Dissociation Mass Spectrometry*

    PubMed Central

    Song, Hongjian; Olsen, Ole H.; Persson, Egon; Rand, Kasper D.

    2014-01-01

    Factor VIIa (FVIIa) is a trypsin-like protease that plays an important role in initiating blood coagulation. Very limited structural information is available for the free, inactive form of FVIIa that circulates in the blood prior to vascular injury and the molecular details of its activity enhancement remain elusive. Here we have applied hydrogen/deuterium exchange mass spectrometry coupled to electron transfer dissociation to pinpoint individual residues in the heavy chain of FVIIa whose conformation and/or local interaction pattern changes when the enzyme transitions to the active form, as induced either by its cofactor tissue factor or a covalent active site inhibitor. Identified regulatory residues are situated at key sites across one continuous surface of the protease domain spanning the TF-binding helix across the activation pocket to the calcium binding site and are embedded in elements of secondary structure and at the base of flexible loops. Thus these residues are optimally positioned to mediate crosstalk between functional sites in FVIIa, particularly the cofactor binding site and the active site. Our results unambiguously show that the conformational allosteric activation signal extends to the EGF1 domain in the light chain of FVIIa, underscoring a remarkable intra- and interdomain allosteric regulation of this trypsin-like protease. PMID:25344622

  7. Global kinetic analysis of seeded BSA aggregation.

    PubMed

    Sahin, Ziya; Demir, Yusuf Kemal; Kayser, Veysel

    2016-04-30

    Accelerated aggregation studies were conducted around the melting temperature (Tm) to elucidate the kinetics of seeded BSA aggregation. Aggregation was tracked by SEC-HPLC and intrinsic fluorescence spectroscopy. Time evolution of monomer, dimer and soluble aggregate concentrations were globally analysed to reliably deduce mechanistic details pertinent to the process. Results showed that BSA aggregated irreversibly through both sequential monomer addition and aggregate-aggregate interactions. Sequential monomer addition proceeded only via non-native monomers, starting to occur only by 1-2°C below the Tm. Aggregate-aggregate interactions were the dominant mechanism below the Tm due to an initial presence of small aggregates that acted as seeds. Aggregate-aggregate interactions were significant also above the Tm, particularly at later stages of aggregation when sequential monomer addition seemed to cease, leading in some cases to insoluble aggregate formation. The adherence (or non-thereof) of the mechanisms to Arrhenius kinetics were discussed alongside possible implications of seeding for biopharmaceutical shelf-life and spectroscopic data interpretation, the latter of which was found to often be overlooked in BSA aggregation studies. PMID:26970282

  8. Soft Mathematical Aggregation in Safety Assessment and Decision Analysis

    SciTech Connect

    Cooper, J. Arlin

    1999-06-10

    This paper improves on some of the limitations of conventional safety assessment and decision analysis methods. It develops a top-down mathematical method for expressing imprecise individual metrics as possibilistic or fuzzy numbers and shows how they may be combined (aggregated) into an overall metric, also portraying the inherent uncertainty. Both positively contributing and negatively contributing factors are included. Metrics are weighted according to significance of the attribute and evaluated as to contribution toward the attribute. Aggregation is performed using exponential combination of the metrics, since the accumulating effect of such factors responds less and less to additional factors. This is termed soft mathematical aggregation. Dependence among the contributing factors is accounted for by incorporating subjective metrics on overlap of the factors and by correspondingly reducing the overall contribution of these combinations to the overall aggregation. Decisions corresponding to the meaningfulness of the results are facilitated in several ways. First, the results are compared to a soft threshold provided by a sigmoid function. Second, information is provided on input ''Importance'' and ''Sensitivity,'' in order to know where to place emphasis on controls that may be necessary. Third, trends in inputs and outputs are tracked in order to add important information to the decision process. The methodology has been implemented in software.

  9. Expression of organophosphorus-degradation gene ( opd) in aggregating and non-aggregating filamentous nitrogen-fixing cyanobacteria

    NASA Astrophysics Data System (ADS)

    Li, Qiong; Tang, Qing; Xu, Xudong; Gao, Hong

    2010-11-01

    Genetic engineering in filamentous N2-fixing cyanobacteria usually involves Anabaena sp. PCC 7120 and several other non-aggregating species. Mass culture and harvest of such species are more energy consuming relative to aggregating species. To establish a gene transfer system for aggregating species, we tested many species of Anabaena and Nostoc, and identified Nostoc muscorum FACHB244 as a species that can be genetically manipulated using the conjugative gene transfer system. To promote biodegradation of organophosphorus pollutants in aquatic environments, we introduced a plasmid containing the organophosphorus-degradation gene ( opd) into Anabaena sp. PCC 7120 and Nostoc muscorum FACHB244 by conjugation. The opd gene was driven by a strong promoter, P psbA . From both species, we obtained transgenic strains having organophosphorus-degradation activities. At 25°C, the whole-cell activities of the transgenic Anabaena and Nostoc strains were 0.163±0.001 and 0.289±0.042 unit/μg Chl a, respectively. However, most colonies resulting from the gene transfer showed no activity. PCR and DNA sequencing revealed deletions or rearrangements in the plasmid in some of the colonies. Expression of the green fluorescent protein gene from the same promoter in Anabaena sp. PCC 7120 showed similar results. These results suggest that there is the potential to promote the degradation of organophosphorus pollutants with transgenic cyanobacteria and that selection of high-expression transgenic colonies is important for genetic engineering of Anabaena and Nostoc species. For the first time, we established a gene transfer and expression system in an aggregating filamentous N2-fixing cyanobacterium. The genetic manipulation system of Nostoc muscorum FACHB244 could be utilized in the elimination of pollutants and large-scale production of valuable proteins or metabolites.

  10. Environmentalism and natural aggregate mining

    USGS Publications Warehouse

    Drew, L.J.; Langer, W.H.; Sachs, J.S.

    2002-01-01

    Sustaining a developed economy and expanding a developing one require the use of large volumes of natural aggregate. Almost all human activity (commercial, recreational, or leisure) is transacted in or on facilities constructed from natural aggregate. In our urban and suburban worlds, we are almost totally dependent on supplies of water collected behind dams and transported through aqueducts made from concrete. Natural aggregate is essential to the facilities that produce energy-hydroelectric dams and coal-fired powerplants. Ironically, the utility created for mankind by the use of natural aggregate is rarely compared favorably with the environmental impacts of mining it. Instead, the empty quarries and pits are seen as large negative environmental consequences. At the root of this disassociation is the philosophy of environmentalism, which flavors our perceptions of the excavation, processing, and distribution of natural aggregate. The two end-member ideas in this philosophy are ecocentrism and anthropocentrism. Ecocentrism takes the position that the natural world is a organism whose arteries are the rivers-their flow must not be altered. The soil is another vital organ and must not be covered with concrete and asphalt. The motto of the ecocentrist is "man must live more lightly on the land." The anthropocentrist wants clean water and air and an uncluttered landscape for human use. Mining is allowed and even encouraged, but dust and noise from quarry and pit operations must be minimized. The large volume of truck traffic is viewed as a real menace to human life and should be regulated and isolated. The environmental problems that the producers of natural aggregate (crushed stone and sand and gravel) face today are mostly difficult social and political concerns associated with the large holes dug in the ground and the large volume of heavy truck traffic associated with quarry and pit operations. These concerns have increased in recent years as society's demand for

  11. Light Scattering From Fractal Titania Aggregates

    NASA Astrophysics Data System (ADS)

    Pande, Rajiv; Sorensen, Christopher M.

    1996-03-01

    We studied the fractal morphology of titania aggregates by light scattering. Titanium dioxide particles were generated by the thermal decomposition of titanium tetra-isopropoxide(TTIP) in a glass furnace at various temperatures in the range of 100 - 500^o C. We scattered vertically polarized He-Ne laser (λ = 6328Ålight from a laminar aerosol stream of particles and measured the optical structure factor. This structure factor shows Rayleigh, Guinier, fractal and Porod regimes. The radius of gyration Rg was determined from the Guinier analysis. The data were then fit to the Fisher-Burford form to determine the fractal dimension of about 2.0. This fit also delineated the crossover from the fractal to Porod regime, which can be used to determine the monomer particle size of about 0.1 μm. These optical measurements will be compared to electron microscope analysis of aggregates collected from the aerosol. This work was supported by NSF grant CTS-9908153.

  12. Markov Modeling with Soft Aggregation for Safety and Decision Analysis

    SciTech Connect

    COOPER,J. ARLIN

    1999-09-01

    The methodology in this report improves on some of the limitations of many conventional safety assessment and decision analysis methods. A top-down mathematical approach is developed for decomposing systems and for expressing imprecise individual metrics as possibilistic or fuzzy numbers. A ''Markov-like'' model is developed that facilitates combining (aggregating) inputs into overall metrics and decision aids, also portraying the inherent uncertainty. A major goal of Markov modeling is to help convey the top-down system perspective. One of the constituent methodologies allows metrics to be weighted according to significance of the attribute and aggregated nonlinearly as to contribution. This aggregation is performed using exponential combination of the metrics, since the accumulating effect of such factors responds less and less to additional factors. This is termed ''soft'' mathematical aggregation. Dependence among the contributing factors is accounted for by incorporating subjective metrics on ''overlap'' of the factors as well as by correspondingly reducing the overall contribution of these combinations to the overall aggregation. Decisions corresponding to the meaningfulness of the results are facilitated in several ways. First, the results are compared to a soft threshold provided by a sigmoid function. Second, information is provided on input ''Importance'' and ''Sensitivity,'' in order to know where to place emphasis on considering new controls that may be necessary. Third, trends in inputs and outputs are tracked in order to obtain significant information% including cyclic information for the decision process. A practical example from the air transportation industry is used to demonstrate application of the methodology. Illustrations are given for developing a structure (along with recommended inputs and weights) for air transportation oversight at three different levels, for developing and using cycle information, for developing Importance and

  13. Pregnancy rates and corpus luteum-related factors affecting pregnancy establishment in bovine recipients synchronized for fixed-time embryo transfer.

    PubMed

    Siqueira, L G B; Torres, C A A; Souza, E D; Monteiro, P L J; Arashiro, E K N; Camargo, L S A; Fernandes, C A C; Viana, J H M

    2009-10-15

    The objective was to investigate the influence of corpora lutea physical and functional characteristics on pregnancy rates in bovine recipients synchronized for fixed-time embryo transfer (FTET). Crossbred (Bos taurus taurus x Bos taurus indicus) nonlactating cows and heifers (n=259) were treated with the following protocol: 2mg estradiol benzoate (EB) plus an intravaginal progesterone device (CIDR 1.9g progesterone; Day 0); 400 IU equine chorionic gonadotropin (eCG; Day 5); prostaglandin F(2alpha) (PGF(2alpha)) and CIDR withdrawal (Day 8); and 1mg EB (Day 9). Ovarian ultrasonography and blood sample collections were performed on Day 17. Of the 259 cattle initially treated, 197 (76.1%) were suitable recipients; they received a single, fresh, quality grade 1 or 2 in vivo-derived (n=90) or in vitro-produced (n=87) embryo on Day 17. Pregnancy rates (23 d after embryo transfer) were higher for in vivo-derived embryos than for in vitro-produced embryos (58.8% vs. 31.0%, respectively; P<0.001). Mean (+/-SD) plasma progesterone (P(4)) concentration was higher in cattle that became pregnant than that in nonpregnant cattle (5.2+/-5.0 vs. 3.8+/-2.4 ng/mL; P=0.02). Mean pixel values (71.8+/-1.3 vs. 71.2+/-1.1) and pixel heterogeneity (14.8+/-0.3 vs. 14.5+/-0.5) were similar between pregnant and nonpregnant recipients (P>0.10). No significant relationship was detected between pregnancy outcome and plasma P(4), corpus luteum area, or corpus luteum echotexture. Embryo type, however, affected the odds of pregnancy. In conclusion, corpus luteum-related traits were poor predictors of pregnancy in recipients. The type of embryo, however, was a major factor affecting pregnancy outcome. PMID:19709722

  14. Photoinduced electron transfer (PET) based label-free aptasensor for platelet-derived growth factor-BB and its logic gate application.

    PubMed

    Wang, Guangfeng; Zhu, Yanhong; Chen, Ling; Zhang, Xiaojun

    2015-01-15

    Platelet-derived growth factor-BB (PDGF-BB) is often overexpressed in human malignant tumors as an indicator for tumor angiogenesis. Here by the photoinduced electron transfer (PET) between DNA-Ag fluorescent nanoclusters (NCs) and G-quadruplex/hemin complexes, we present a sensitive label-free fluorescent sensor for PDGF-BB. In the presence of PDGF-BB, the specific conjugation with its aptamer induced the conformational change of the duplex-like DNA sequence, releasing the G-quadruplex sequence part. Then in the presence of hemin and K(+), the horseradish peroxidase mimicking DNAzyme (HRP-DNAzyme) was formed. With the electron transfer between the DNA-Ag NCs to the hemin Fe (III) center of HRP-DNAzyme, the PET occurred with a decrease in the fluorescence intensity of the DNA-Ag NCs. The detection performance such as selectivity, linear dynamic range, sensitivity, and the quenching capability of HRP-DNAzyme were estimated. The detection range for PDGF-BB is from 5×10(-13) to 1×10(-8) M and the detection limit is 1×10(-13) M. The experimental results confirmed that the novel fluorescent aptasensor possessed a good sensitivity and high selectivity for PDGF-BB. In addition, the developed probe is nontoxic, label-free only involving one-step hybridization without sophisticated fabrication process. Furthermore, based on this quenching mode occurred by PDGF-BB and hemin, using PDGF-BB and hemin as inputs and the fluorescence signal as an output, a logic gate has been fabricated. PMID:25150781

  15. MR Assessment of Myocardial Perfusion, Viability, and Function after Intramyocardial Transfer of VM202, a New Plasmid Human Hepatocyte Growth Factor in Ischemic Swine Myocardium1

    PubMed Central

    Saeed, Maythem; Martin, Alastair; Ursell, Phillip; Do, Loi; Bucknor, Matt; Higgins, Charles B.; Saloner, David

    2008-01-01

    Purpose: VM202, a newly constructed plasmid human hepatocyte growth factor, was transferred intramyocardially after infarction for the purpose of evaluating this strategy as a therapeutic approach for protection from left ventricular (LV) remodeling. Materials and Methods: The institutional animal care and use committee approved this study. Pigs underwent coronary artery occlusion and reperfusion and served as either control (n = 8) or VM202-treated (n = 8) animals. VM202 was transferred intramyocardially into four infarcted and four periinfarcted sites. Cardiac magnetic resonance (MR) imaging (cine, perfusion, delayed enhancement) was performed in acute (3 days) and chronic (50 days ± 3 [standard error of the mean]) infarction. Histopathologic findings were used to characterize and quantify neovascularization. The t test was utilized to compare treated and control groups and to assess changes over time. Results: In acute infarction, MR imaging estimates of function, perfusion, and viability showed no difference between the groups. In chronic infarction, however, VM202 increased maximum signal intensity and upslope at first-pass perfusion imaging and reduced infarct size at perfusion and delayed-enhancement imaging. These changes were associated with a decrease in end-diastolic (2.15 mL/kg ± 0.12 to 1.73 mL/kg ± 0.10, P < .01) and end-systolic (1.33 mL/kg ± 0.07 to 0.92 mL/kg ± 0.08, P < .001) volumes and an increase in ejection fraction (38.2% ± 1.3 to 47.0% ± 1.8, P < .001). In contrast, LV function deteriorated further in control animals. Compared with control animals, VM202-treated animals revealed peninsulas and/or islands of viable myocardium in infarcted and periinfarcted regions and greater number of capillaries (218 per square millimeter ± 19 vs 119 per square millimeter ± 17, P < .05) and arterioles (21 per square millimeter ± 4 vs 3 per square millimeter ± 1, P < .001). Conclusion: Intramyocardial transfer of VM202 improved myocardial

  16. Two Dimensional Aggregation Behaviors of Quinoxaline Dendrimers.

    PubMed

    Choi, Soyoung; Lee, Hoik; Kim, Hwan Kyu; Lee, Sang Uck; Sohn, Daewon

    2015-02-01

    This study focuses on the molecular behavior of two dendrimers containing a hydrophilic core group (carboxyl group) and hydrophobic branches (quinoxaline and methoxyphenyl groups), 2,3-bis(4-(2,3- bis(4-methoxyphenyl)quinoxalin-6-yloxy)phenyl)quinoxaline-6-carb-oxylic acid (G2) and 2,3-bis(4-(2,3-bis(4-(2,3-bis(4-methoxyphenyl)quinoxalin-6-yloxy)phe-nyl)quinoxalin-6-y-oxy)phenyl) quin oxaline-6-carboxylic acid (G3) at the air-water interface. To understand the mechanism of the self-assembly of these molecules, we measured the surface pressure-area (III-A) isotherm and investigated the surface morphology of Langmuir-Blodgett films transferred onto hydrophilic silicon wafers using atomic force microscopy (AFM). Upon compression, G2 molecules stand up and steadily make close-packed monolayer whereas G3 molecules form circular domains and gradually make aggregates of domains. These results were confirmed by the X-ray Reflectivity (XRR) profiles of G2 and G3 monolayers transferred onto silicon substrates. PMID:26353682

  17. Mesoscale Simulation of Asphaltene Aggregation.

    PubMed

    Wang, Jiang; Ferguson, Andrew L

    2016-08-18

    Asphaltenes constitute a heavy aromatic crude oil fraction with a propensity to aggregate and precipitate out of solution during petroleum processing. Aggregation is thought to proceed according to the Yen-Mullins hierarchy, but the molecular mechanisms underlying mesoscopic assembly remain poorly understood. By combining coarse-grained molecular models parametrized using all-atom data with high-performance GPU hardware, we have performed molecular dynamics simulations of the aggregation of hundreds of asphaltenes over microsecond time scales. Our simulations reveal a hierarchical self-assembly mechanism consistent with the Yen-Mullins model, but the details are sensitive and depend on asphaltene chemistry and environment. At low concentrations asphaltenes exist predominantly as dispersed monomers. Upon increasing concentration, we first observe parallel stacking into 1D rod-like nanoaggregates, followed by the formation of clusters of nanoaggregates associated by offset, T-shaped, and edge-edge stacking. Asphaltenes possessing long aliphatic side chains cannot form nanoaggregate clusters due to steric repulsions between their aliphatic coronae. At very high concentrations, we observe a porous percolating network of rod-like nanoaggregates suspended in a sea of interpenetrating aliphatic side chains with a fractal dimension of ∼2. The lifetime of the rod-like aggregates is described by an exponential distribution reflecting a dynamic equilibrium between coagulation and fragmentation. PMID:27455391

  18. RAGG - R EPISODIC AGGREGATION PACKAGE

    EPA Science Inventory

    The RAGG package is an R implementation of the CMAQ episodic model aggregation method developed by Constella Group and the Environmental Protection Agency. RAGG is a tool to provide climatological seasonal and annual deposition of sulphur and nitrogen for multimedia management. ...

  19. Motivational Influences on Transfer

    ERIC Educational Resources Information Center

    Pugh, Kevin J.; Bergin, David A.

    2006-01-01

    Both transfer and motivation are important constructs accompanied by extensive bodies of literature. However, there is a lack of integration of the 2 constructs. This article analyzes the potential indirect influence of motivational factors on transfer by reviewing studies that examine the influence of motivation on cognitive processes related to…

  20. An Aggregation Advisor for Ligand Discovery.

    PubMed

    Irwin, John J; Duan, Da; Torosyan, Hayarpi; Doak, Allison K; Ziebart, Kristin T; Sterling, Teague; Tumanian, Gurgen; Shoichet, Brian K

    2015-09-10

    Colloidal aggregation of organic molecules is the dominant mechanism for artifactual inhibition of proteins, and controls against it are widely deployed. Notwithstanding an increasingly detailed understanding of this phenomenon, a method to reliably predict aggregation has remained elusive. Correspondingly, active molecules that act via aggregation continue to be found in early discovery campaigns and remain common in the literature. Over the past decade, over 12 thousand aggregating organic molecules have been identified, potentially enabling a precedent-based approach to match known aggregators with new molecules that may be expected to aggregate and lead to artifacts. We investigate an approach that uses lipophilicity, affinity, and similarity to known aggregators to advise on the likelihood that a candidate compound is an aggregator. In prospective experimental testing, five of seven new molecules with Tanimoto coefficients (Tc's) between 0.95 and 0.99 to known aggregators aggregated at relevant concentrations. Ten of 19 with Tc's between 0.94 and 0.90 and three of seven with Tc's between 0.89 and 0.85 also aggregated. Another three of the predicted compounds aggregated at higher concentrations. This method finds that 61 827 or 5.1% of the ligands acting in the 0.1 to 10 μM range in the medicinal chemistry literature are at least 85% similar to a known aggregator with these physical properties and may aggregate at relevant concentrations. Intriguingly, only 0.73% of all drug-like commercially available compounds resemble the known aggregators, suggesting that colloidal aggregators are enriched in the literature. As a percentage of the literature, aggregator-like compounds have increased 9-fold since 1995, partly reflecting the advent of high-throughput and virtual screens against molecular targets. Emerging from this study is an aggregator advisor database and tool ( http://advisor.bkslab.org ), free to the community, that may help distinguish between

  1. Transfer factors to Whitetail deer: comparison of stomach-content, plant-sample and soil-sample concentrations as the denominator.

    PubMed

    Sheppard, S C

    2013-12-01

    A recent study measured transfer factors for 49 elements in hunter-killed Whitetail deer (Odocoileus virginianus), using concentrations in the stomach content as the substrate/denominator to compute muscle/vegetation concentration ratios (CR(m-stomach)) and daily fractional transfer factors (Ff). Using the stomach content ensured an accurate representation of what the deer ate, except that it was limited in time to the vegetation selected by the animal just before it was killed. Here, two alternatives are considered, one where the feed is represented by samples of 21 different vegetation types that deer may have eaten in the area (CR(m-plant)), and the other is using soil concentration in the region as the denominator (CR(m-soil)). The latter is the formulation used in the ERICA tool, and other sources, for risk assessment to non-human biota. Across elements, (log) concentrations in all the media were highly correlated. The stomach contents had consistently higher ash and rare earth element concentrations than the sampled (and washed) vegetation and this was attributed to soil or dust ingestion. This lends credence to the use of soil-based CRm-soil values, despite (or more accurately because of) the inclusive yet gross simplicity of the approach. However, it was clear that variation of CR(m-soil) values was larger than for CR(m-stomach) or CR(m-plant), even if soil load on vegetation was included in the latter values. It was also noted that the variation in CR(m-soil) computed from the product of CR(m-plant) and CR(plant-soil) (where CR(plant-soil) is the plant/soil concentration ratio) was somewhat larger than the variation inherent in CR(m-soil) data. Thus it is reasonable to estimate CR(m-soil) from CR(m-plant) and CR(plant-soil) if observed CR(m-soil) values are not available, but this introduces further uncertainty. PMID:23287432

  2. Particle Aggregation During Fe(III) Bioreduction in Nontronite

    NASA Astrophysics Data System (ADS)

    Jaisi, D. P.; Dong, H.; Hi, Z.; Kim, J.

    2005-12-01

    This study was performed to evaluate the rate and mechanism of particle aggregation during bacterial Fe (III) reduction in different size fractions of nontronite and to investigate the role of different factors contributing to particle aggregation. To achieve this goal, microbial Fe(III) reduction experiments were performed with lactate as an electron donor, Fe(III) in nontronite as an electron acceptor, and AQDS as an electron shuttle in bicarbonate buffer using Shewanella putrefaceins CN32. These experiments were performed with and without Na- pyrophosphate as a dispersant in four size fractions of nontronite (0.12-0.22, 0.41-0.69, 0.73-0.96 and 1.42-1.8 mm). The rate of nontronite aggregation during the Fe(III) bioreduction was measured by analyzing particle size distribution using photon correlation spectroscopy (PCS) and SEM images analysis. Similarly, the changes in particle morphology during particle aggregation were determined by analyses of SEM images. Changes in particle surface charge were measured with electrophoretic mobility analyzer. The protein and carbohydrate fraction of EPS produced by cells during Fe(III) bioreduction was measured using Bradford and phenol-sulfuric acid extraction method, respectively. In the presence of the dispersant, the extent of Fe(III) bioreduction was 11.5-12.2% within the first 56 hours of the experiment. There was no measurable particle aggregation in control experiments. The PCS measurements showed that the increase in the effective diameter (95% percentile) was by a factor of 3.1 and 1.9 for particle size of 0.12-0.22 mm and 1.42-1.80 mm, respectively. The SEM image analyses also gave the similar magnitude of increase in particle size. In the absence of the dispersant, the extent of Fe(III) bioreduction was 13.4-14.5% in 56 hours of the experiment. The rate of aggregation was higher than that in the presence of the dispersant. The increase in the effective diameter (95% percentile) was by a factor of 13.6 and 4.1 for

  3. Femtosecond probe of structural analogies between chlorosomes and bacteriochlorophyll c aggregates.

    PubMed Central

    Savikhin, S; van Noort, P I; Blankenship, R E; Struve, W S

    1995-01-01

    Bacteriochlorophyll c pigments extracted from light harvesting chlorosomes in green photosynthetic bacteria are known to self-assemble into aggregates whose electronic spectroscopy resembles that of intact chlorosomes. Femtosecond optical experiments reveal that the chlorosomes and their reconstituted aggregates exhibit closely analogous internal energy transfer kinetics and exciton state evolution. These comparisons furnish compelling new evidence that proteins do not exert a major local role in the BChl c antenna pigment organization of intact chlorosomes. PMID:8519963

  4. The Data Aggregation Project: Free Software that Transforms the Student Laboratory Experience.

    ERIC Educational Resources Information Center

    Brewer, Steven D.; Hoogendky, Tom; Hoagland, Donald B.

    2003-01-01

    Found that in an introductory biology course at the University of Massachusetts Amherst, adoption of the Data Aggregation Project (free software that allows students in a course to aggregate a large body of data for some particular problem) resulted in an increase in the number of data points students analyzed per semester by a factor of almost…

  5. Thallium at the interface of soil and green cabbage (Brassica oleracea L. var. capitata L.): soil-plant transfer and influencing factors.

    PubMed

    Jia, Yanlong; Xiao, Tangfu; Zhou, Guangzhu; Ning, Zengping

    2013-04-15

    Thallium (Tl) is a non-essential and toxic trace metal found in many plants, but it can accumulate at particularly high concentration in green cabbage (Brassica oleracea L. var. capitata L.). The aim of this study is to explore the transfer and accumulation of Tl at the interface of rhizospheric soil and green cabbage from a long-term Tl contaminated site in southwestern Guizhou Province, China. Influencing factors such as Tl distribution in various soil fractions and physical-chemical characteristics of rhizospheric soil were also investigated. Our results demonstrated that green cabbage had high accumulation of Tl, with most bioconcentration factor (BF) values exceeding 1, and up to a maximum level of 11. The enrichment of Tl in the green cabbage tissues followed a descending order, i.e. old leaves>fresh leaves>stems≈roots. The stems functioned as a channel for Tl transportation to the leaves, where most of the Tl (greater than 80%) was found to accumulate. In the rhizospheric soils, 62-95% of Tl existed in the residual fraction, while lower concentrations of Tl (on average, 1.7% of total T1 in rhizospheric soil) were found in the water and acid soluble fractions. The major fraction of labile Tl was located in the reducible fraction (9%). Our results also suggested that the uptake and enrichment of Tl in green cabbage were affected by Tl concentrations, soil water content, soil pH, soil organic material (SOM) and cation exchange capacity (CEC) in rhizospheric soil. PMID:23474259

  6. Proton elastic form factor ratios to Q{sup 2}=3.5 GeV{sup 2} by polarization transfer

    SciTech Connect

    Punjabi, V.; Perdrisat, C.F.; Gerstner, G.; Pentchev, L.; Rutledge, G.; Strauch, S.; Wijesooriya, K.; Aniol, K.A.; Epstein, M.B.; Margaziotis, D.J.; Baker, F.T.; Templon, J.A.; Berthot, J.; Bertin, P.Y.; Besson, A.; Fonvieille, H.; Jaminion, S.; Laveissiere, G.

    2005-05-01

    The ratio of the proton elastic electromagnetic form factors, G{sub Ep}/G{sub Mp}, was obtained by measuring P{sub t} and P{sub l}, the transverse and longitudinal recoil proton polarization components, respectively, for the elastic e{sup {yields}}p{yields}ep{sup {yields}}reaction in the four-momentum transfer squared range of 0.5 to 3.5 GeV{sup 2}. In the single-photon exchange approximation, G{sub Ep}/G{sub Mp} is directly proportional to P{sub t}/P{sub l}. The simultaneous measurement of P{sub t} and P{sub l} in a polarimeter reduces systematic uncertainties. The results for G{sub Ep}/G{sub Mp} show a systematic decrease with increasing Q{sup 2}, indicating for the first time a definite difference in the distribution of charge and magnetization in the proton. The data have been reanalyzed and their systematic uncertainties have become significantly smaller than those reported previously.

  7. Variability of 137Cs and 40K soil-to-fruit transfer factor in tropical lemon trees during the fruit development period.

    PubMed

    Velasco, H; Cid, A S; Anjos, R M; Zamboni, C B; Rizzotto, M; Valladares, D L; Juri Ayub, J

    2012-02-01

    In this investigation we evaluate the soil uptake of (137)Cs and (40)K by tropical plants and their consequent translocation to fruits, by calculating the soil-to-fruit transfer factors defined as F(v) = [concentration of radionuclide in fruit (Bq kg(-1) dry mass)/concentration of radionuclide in soil (Bq kg(-1) dry mass in upper 20 cm)]. In order to obtain F(v) values, the accumulation of these radionuclides in fruits of lemon trees (Citrus limon B.) during the fruit growth was measured. A mathematical model was calibrated from the experimental data allowing simulating the incorporation process of these radionuclides by fruits. Although the fruit incorporates a lot more potassium than cesium, both radionuclides present similar absorption patterns during the entire growth period. F(v) ranged from 0.54 to 1.02 for (40)K and from 0.02 to 0.06 for (137)Cs. Maximum F(v) values are reached at the initial time of fruit growth and decrease as the fruit develops, being lowest at the maturation period. As a result of applying the model a decreasing exponential function is derived for F(v) as time increases. The agreement between the theoretical approach and the experimental values is satisfactory. PMID:22115437

  8. The structure of a ring-opened proliferating cell nuclear antigen–replication factor C complex revealed by fluorescence energy transfer

    PubMed Central

    Zhuang, Zhihao; Yoder, Bonita L.; Burgers, Peter M. J.; Benkovic, Stephen J.

    2006-01-01

    Numerous proteins that function in DNA metabolic pathways are known to interact with the proliferating cell nuclear antigen (PCNA). The important function of PCNA in stimulating various cellular activities requires its topological linkage with DNA. Loading of the circular PCNA onto duplex DNA requires the activity of a clamp-loader [replication factor C (RFC)] complex and the energy derived from ATP hydrolysis. The mechanistic and structural details regarding PCNA loading by the RFC complex are still developing. In particular, the positive identification of a long-hypothesized structure of an open clamp–RFC complex as an intermediate in loading has remained elusive. In this study, we capture an open yeast PCNA clamp in a complex with RFC through fluorescence energy transfer experiments. We also follow the topological transitions of PCNA in the various steps of the clamp-loading pathway through both steady-state and stopped-flow fluorescence studies. We find that ATP effectively drives the clamp-loading process to completion with the formation of the closed PCNA bound to DNA, whereas ATPγS cannot. The information derived from this work complements that obtained from previous structural and mechanistic studies and provides a more complete picture of a eukaryotic clamp-loading pathway using yeast as a paradigm. PMID:16476998

  9. Interferon-alpha and transfer factor in the treatment of multiple sclerosis: a double-blind, placebo-controlled trial. AUSTIMS Research Group.

    PubMed Central

    1989-01-01

    The role of interferon-alpha (IFN-alpha) and transfer factor (TF) in the treatment of multiple sclerosis was investigated in a prospective, multi-centric, three year, double-blind, placebo-controlled trial. One hundred and eighty two patients with clinically definite multiple sclerosis were randomised into three treatment groups whose compositions were found to be similar for demographic and prognostic variables including HLA status. Subcutaneous injections of IFN-alpha (3 x 10(6) units), TF (0.5 units) manufactured from leucocytes of cohabiting donors, or placebo were given twice weekly for two months, once weekly for 10 months then fortnightly for 24 months. One hundred and fifty three patients completed the injection regimen. There was no significant difference in the progression of disability for multiple sclerosis patients in either the IFN-alpha or TF-treated groups compared with the placebo group. Similarly, change in visual evoked responses (VER), and in number of oligoclonal bands (OCB) and the level of myelin basic protein (MBP) in the cerebrospinal fluid (CSF) over the trial period did not differ significantly between the three groups. However, the IFN-alpha-treated group had significantly more reported adverse drug reactions and patient withdrawals than either of the other two groups. PMID:2659737

  10. Proton elastic form factor ratios to Q{sup 2} = 3.5 GeV{sup 2} by polarization transfer

    SciTech Connect

    V. Punjabi; C.F. Perdrisat; et al

    2005-01-01

    The ratio of the proton elastic electromagnetic form factors, G{sub E{sub p}}/G{sub M{sub p}}, was obtained by measuring P{sub t} and P{sub {ell}}, the transverse and longitudinal recoil proton polarization components, respectively, for the elastic {rvec e}p {yields} e{rvec p} reaction in the four-momentum transfer squared range of 0.5 to 3.5 GeV{sup 2}. In the single-photon exchange approximation, the ratio G{sub E{sub p}}/G{sub M{sub p}} is directly proportional to the ratio P{sub t}/P{sub {ell}}. The simultaneous measurement of P{sub t} and P{sub {ell}} in a polarimeter reduces systematic uncertainties. The results for the ratio G{sub E{sub p}}/G{sub M{sub p}} show a systematic decrease with increasing Q{sup 2}, indicating for the first time a definite difference in the distribution of charge and magnetization in the proton. The data have been re-analyzed and systematic uncertainties have become significantly smaller than previously published results.

  11. Exosomes mediate intercellular transfer of pro-fibrogenic connective tissue growth factor (CCN2) between hepatic stellate cells, the principal fibrotic cells in the liver

    PubMed Central

    Charrier, Alyssa; Chen, Ruju; Chen, Li; Kemper, Sherri; Hattori, Takako; Takigawa, Masaharu; Brigstock, David R.

    2014-01-01

    Background Fibrogenic pathways in the liver are principally regulated by hepatic stellate cells (HSC) which produce and respond to fibrotic mediators such as connective tissue growth factor (CCN2). The aim of this study was to determine whether CCN2 is shuttled between HSC in membraneous nanovesicles, or “exosomes”. Methods Exosomes were incubated with HSC after isolation from conditioned medium of control or CCN2-GFP-transfected primary mouse HSC or human LX-2 HSC. Some exosomes were flourescently stained with PKH26. HSC co-culture experiments were performed in the presence of GW4869 exosome inhibitor. CCN2 or CCN2-GFP were evaluated by qRT-PCR or Western blot. Results HSC-derived exosomes contained CCN2 or CCN2 mRNA, each of which increased in concentration during HSC activation or after transfection of HSC with CCN2-GFP. Exosomes, stained with either PKH26 or purified from CCN2-GFP-transfected cells, were taken up by activated or quiescent HSC resulting in CCN2-GFP delivery, as shown by their direct addition to recipient cells or by the GW4869-dependency of donor HSC. Conclusions CCN2 is packaged into secreted nano-sized exosomes which mediate its intercellular transfer between HSC. Exosomal CCN2 may amplify or fine-tune fibrogenic signaling and may, in conjunction with other exosome constituents, have utility as a noninvasive biomarker to assess hepatic fibrosis. PMID:24882759

  12. On the radiative properties of soot aggregates part 1: Necking and overlapping

    NASA Astrophysics Data System (ADS)

    Yon, J.; Bescond, A.; Liu, F.

    2015-09-01

    There is a strong interest in accurately modelling the radiative properties of soot aggregates (also known as black carbon particles) emitted from combustion systems and fires to gain improved understanding of the role of black carbon to global warming. This study conducted a systematic investigation of the effects of overlapping and necking between neighbouring primary particles on the radiative properties of soot aggregates using the discrete dipole approximation. The degrees of overlapping and necking are quantified by the overlapping and necking parameters. Realistic soot aggregates were generated numerically by constructing overlapping and necking to fractal aggregates formed by point-touch primary particles simulated using a diffusion-limited cluster aggregation algorithm. Radiative properties (differential scattering, absorption, total scattering, specific extinction, asymmetry factor and single scattering albedo) were calculated using the experimentally measured soot refractive index over the spectral range of 266-1064 nm for 9 combinations of the overlapping and necking parameters. Overlapping and necking affect significantly the absorption and scattering properties of soot aggregates, especially in the near UV spectrum due to the enhanced multiple scattering effects within an aggregate. By using correctly modified aggregate properties (fractal dimension, prefactor, primary particle radius, and the number of primary particle) and by accounting for the effects of multiple scattering, the simple Rayleigh-Debye-Gans theory for fractal aggregates can reproduce reasonably accurate radiative properties of realistic soot aggregates.

  13. Floc strength characterization technique. An insight into silica aggregation.

    PubMed

    Hermawan, Mandalena; Bushell, Graeme C; Craig, Vincent S J; Teoh, Wey Yang; Amal, Rose

    2004-07-20

    This paper tests an approach to the estimation of relative particle bond strength based on the nondimensional floc and aggregation factors. The strength of flocs formed by aggregating nanosized silica particles with the addition of potassium chloride (KCl) or cationic surfactants, alkyltrimethylammonium bromide (mixture of CTAB, DTAB, and MTAB) was analyzed. The bonding force of the flocs formed in surfactant compared to that formed in the KCl system was estimated using the new dimensional analysis approach. This force ratio was then compared to that obtained by atomic force microscopy. PMID:15248736

  14. Yeast as a platform to explore polyglutamine toxicity and aggregation.

    PubMed

    Duennwald, Martin L

    2013-01-01

    Protein misfolding is associated with many neurodegenerative diseases, including neurodegenerative diseases caused by polyglutamine expansion proteins, such as Huntington's disease. The model organism baker's yeast (Saccharomyces cerevisiae) has provided important general insights into the basic cellular mechanisms underlying protein misfolding. Furthermore, experiments in yeast have identified cellular factors that modulate the toxicity and the aggregation associated with polyglutamine expansion proteins. Notably, many features discovered in yeast have been proven to be highly relevant in other model organisms and in human pathology. The experimental protocols depicted here serve to reliably determine polyglutamine toxicity and polyglutamine aggregation in yeast. PMID:23719914

  15. Aggregation, stability, and oscillations in different models for host-macroparasite interactions.

    PubMed

    Rosà, Roberto; Pugliese, Andrea

    2002-05-01

    Aggregation is generally recognized as an important factor in the dynamics of host-macroparasite interactions and it has been found relevant in stabilizing the dynamics toward an equilibrium coexistence. In this paper we review the models of Anderson and May (1978, J. Anim. Ecol. 47, 219-247, 249-267) and compare them with some more recently developed models, which incorporate explicit mechanisms (multiple infections or host heterogeneity) for generating aggregation and different degrees of mathematical accuracy. We found that the stabilization yielded by aggregation depends strongly on the mechanism producing the aggregation: multiple infections are much less stabilizing than when aggregation is assumed to be fixed from the outside, while the opposite holds for host heterogeneity. We also give analytical estimates of the period of oscillations occurring when the equilibrium is unstable. Finally, we explore in these models the role of aggregation in host regulation and in determining a threshold value for parasite establishment. PMID:12027618

  16. Cytoplasmic protein aggregates interfere with nucleocytoplasmic transport of protein and RNA.

    PubMed

    Woerner, Andreas C; Frottin, Frédéric; Hornburg, Daniel; Feng, Li R; Meissner, Felix; Patra, Maria; Tatzelt, Jörg; Mann, Matthias; Winklhofer, Konstanze F; Hartl, F Ulrich; Hipp, Mark S

    2016-01-01

    Amyloid-like protein aggregation is associated with neurodegeneration and other pathologies. The nature of the toxic aggregate species and their mechanism of action remain elusive. Here, we analyzed the compartment specificity of aggregate toxicity using artificial β-sheet proteins, as well as fragments of mutant huntingtin and TAR DNA binding protein-43 (TDP-43). Aggregation in the cytoplasm interfered with nucleocytoplasmic protein and RNA transport. In contrast, the same proteins did not inhibit transport when forming inclusions in the nucleus at or around the nucleolus. Protein aggregation in the cytoplasm, but not the nucleus, caused the sequestration and mislocalization of proteins containing disordered and low-complexity sequences, including multiple factors of the nuclear import and export machinery. Thus, impairment of nucleocytoplasmic transport may contribute to the cellular pathology of various aggregate deposition diseases. PMID:26634439

  17. Aggregation of metallochlorophylls - Examination by spectroscopy

    NASA Technical Reports Server (NTRS)

    Boucher, L. J.; Katz, J. J.

    1969-01-01

    Nuclear magnetic resonance measurements determine which metallochlorophylls, besides magnesium-containing chlorophylls, possess coordination aggregation properties. Infrared spectroscopy reveals that only zinc pheophytin and zinc methyl pheophorbide showed significant coordination aggregation, whereas divalent nickel and copper did not.

  18. Oligomeric baroeffect and gas aggregation states

    NASA Technical Reports Server (NTRS)

    Noever, David A.

    1992-01-01

    The baroeffect is analyzed to include a gas that aggregates into higher-order polymers or oligomers. The resulting pressure change is found to vary independently of the molecular weight of the gas components and to depend only on the aggregation or oligomeric order of the gas. With increasing aggregation, diffusive slip velocities are found to increase. The calculations are extended to include general counterdiffusion of two distinct aggregation states (k-, j-mer) for the gas, and the pressure change is derived as a function that is independent of both molecular weight and the absolute aggregation. The only parameter that determines the baroeffect is the ratio of aggregated states, beta = k/j. For gases that reversibly aggregate, possible oscillatory behavior and complex dynamics for pressure are discussed. Gas aggregation may play a role for low-temperature crystal-growth conditions in which vapor concentrations of one (or more) species are high.

  19. Mesoscale aggregation properties of C60 in toluene and chlorobenzene.

    PubMed

    Guo, Rong-Hao; Hua, Chi-Chung; Lin, Po-Chang; Wang, Ting-Yu; Chen, Show-An

    2016-07-20

    The mesoscale aggregation properties of C60 in two distinct aromatic solvents (toluene and chlorobenzene) and a practical range of concentrations (c = 1-2 and c = 1-5 mg mL(-1), respectively) were systematically explored by static/dynamic light scattering (SLS/DLS), small angle X-ray scattering (SAXS), depolarized dynamic light scattering (DDLS), and cryogenic transmission electron microscopy (cryo-TEM) analyses. The central observations were as follows: (1) aggregate species of sizes in the range of several hundred nanometers have been independently revealed by SLS, DLS, and DDLS analyses for both solvent systems. (2) DDLS and cryo-TEM measurements further revealed that while C60 clusters are notably anisotropic (rod-like) in chlorobenzene, they are basically isotropic (spherical) in toluene. (3) Detailed analyses of combined SLS and SAXS profiles suggested that varied, yet self-similar, solvent-induced aggregate units were responsible for the distinct (mesoscale) aggregation features noted above. (4) From a dynamic perspective, specially commissioned DLS measurements ubiquitously displayed two relaxation modes (fast and slow mode), with the second (slow) mode being q (wave vector) independent. While the fast mode in both solvent systems was basically diffusive by nature and leads to geometrical features in good agreement with the above static analyses, the slow mode was analyzed and tentatively suggested to reflect the effect of mutual confinement. (5) Micron-scale aggregate morphology of drop-cast thin films displays similar contrasting features for the two solvent media used. Overall, this study suggests that solvent-induced, nanoscale, aggregate units may be a promising factor to control a hierarchy of microscopic aggregation properties of C60 solutions and thin films. PMID:27376417

  20. Properties of concrete blocks prepared with low grade recycled aggregates.

    PubMed

    Poon, Chi-Sun; Kou, Shi-cong; Wan, Hui-wen; Etxeberria, Miren

    2009-08-01

    Low grade recycled aggregates obtained from a construction waste sorting facility were tested to assess the feasibility of using these in the production of concrete blocks. The characteristics of the sorted construction waste are significantly different from that of crushed concrete rubbles that are mostly derived from demolition waste streams. This is due to the presence of higher percentages of non-concrete components (e.g. >10% soil, brick, tiles etc.) in the sorted construction waste. In the study reported in this paper, three series of concrete block mixtures were prepared by using the low grade recycled aggregates to replace (i) natural coarse granite (10mm), and (ii) 0, 25, 50, 75 and 100% replacement levels of crushed stone fine (crushed natural granite <5mm) in the concrete blocks. Test results on properties such as density, compressive strength, transverse strength and drying shrinkage as well as strength reduction after exposure to 800 degrees C are presented below. The results show that the soil content in the recycled fine aggregate was an important factor in affecting the properties of the blocks produced and the mechanical strength deceased with increasing low grade recycled fine aggregate content. But the higher soil content in the recycled aggregates reduced the reduction of compressive strength of the blocks after exposure to high temperature due probably to the formation of a new crystalline phase. The results show that the low grade recycled aggregates obtained from the construction waste sorting facility has potential to be used as aggregates for making non-structural pre-cast concrete blocks. PMID:19398196