Science.gov

Sample records for aggregate culture system

  1. Reconstruction of a seminiferous tubule-like structure in a 3 dimensional culture system of re-aggregated mouse neonatal testicular cells within a collagen matrix.

    PubMed

    Zhang, Jidong; Hatakeyama, Jun; Eto, Ko; Abe, Shin-Ichi

    2014-09-01

    Male gonad development is initiated by the aggregation of pre-Sertoli cells (SCs), which surround germ cells to form cords. Several attempts to reconstruct testes from dissociated testicular cells have been made; however, only very limited morphogenesis beyond seminiferous cord formation has been achieved. Therefore, we aimed to reconstruct seminiferous tubules using a 3-dimensional (D) re-aggregate culture of testicular cells, which were dissociated from 6-dpp neonatal mice, inside a collagen matrix. We performed a short-term culture (for 3 days) and a long-term culture (up to 3 wks). The addition of KnockOut Serum Replacement (KSR) promoted (1) the enlargement of SC re-aggregates; (2) the attachment of peritubular myoid (PTM) cells around the SC re-aggregates; (3) the sorting of germ cells inside, and Leydig cells outside, seminiferous cord-like structures; (4) the alignment of SC polarity inside a seminiferous cord-like structure relative to the basement membrane; (5) the differentiation of SCs (the expression of the androgen receptor); (6) the formation of a blood-testis-barrier between the SCs; (7) SC elongation and lumen formation; and (8) the proliferation of SCs and spermatogonia, as well as the differentiation of spermatogonia into primary spermatocytes. Eventually, KSR promoted the formation of seminiferous tubule-like structures, which accompanied germ cell differentiation. However, these morphogenetic events did not occur in the absence of KSR. This in vitro system presents an excellent model with which to identify the possible factors that induce these events and to analyze the mechanisms that underlie cellular interactions during testicular morphogenesis and germ cell differentiation.

  2. A population balance equation model of aggregation dynamics in Taxus suspension cell cultures.

    PubMed

    Kolewe, Martin E; Roberts, Susan C; Henson, Michael A

    2012-02-01

    The nature of plant cells to grow as multicellular aggregates in suspension culture has profound effects on bioprocess performance. Recent advances in the measurement of plant cell aggregate size allow for routine process monitoring of this property. We have exploited this capability to develop a conceptual model to describe changes in the aggregate size distribution that are observed over the course of a Taxus cell suspension batch culture. We utilized the population balance equation framework to describe plant cell aggregates as a particulate system, accounting for the relevant phenomenological processes underlying aggregation, such as growth and breakage. We compared model predictions to experimental data to select appropriate kernel functions, and found that larger aggregates had a higher breakage rate, biomass was partitioned asymmetrically following a breakage event, and aggregates grew exponentially. Our model was then validated against several datasets with different initial aggregate size distributions and was able to quantitatively predict changes in total biomass and mean aggregate size, as well as actual size distributions. We proposed a breakage mechanism where a fraction of biomass was lost upon each breakage event, and demonstrated that even though smaller aggregates have been shown to produce more paclitaxel, an optimum breakage rate was predicted for maximum paclitaxel accumulation. We believe this is the first model to use a segregated, corpuscular approach to describe changes in the size distribution of plant cell aggregates, and represents an important first step in the design of rational strategies to control aggregation and optimize process performance.

  3. Aggregation by depletion attraction in cultures of bacteria producing exopolysaccharide

    PubMed Central

    Dorken, Gary; Ferguson, Gail P.; French, Chris E.; Poon, Wilson C. K.

    2012-01-01

    In bacteria, the production of exopolysaccharides—polysaccharides secreted by the cells into their growth medium—is integral to the formation of aggregates and biofilms. These exopolysaccharides often form part of a matrix that holds the cells together. Investigating the bacterium Sinorhizobium meliloti, we found that a mutant that overproduces the exopolysaccharide succinoglycan showed enhanced aggregation, resulting in phase separation of the cultures. However, the aggregates did not appear to be covered in polysaccharides. Succinoglycan purified from cultures was applied to different concentrations of cells, and observation of the phase behaviour showed that the limiting polymer concentration for aggregation and phase separation to occur decreased with increasing cell concentration, suggesting a ‘crowding mechanism’ was occurring. We suggest that, as found in colloidal dispersions, the presence of a non-adsorbing polymer in the form of the exopolysaccharide succinoglycan drives aggregation of S. meliloti by depletion attraction. This force leads to self-organization of the bacteria into small clusters of laterally aligned cells, and, furthermore, leads to aggregates clustering into biofilm-like structures on a surface. PMID:22896568

  4. Development of ultrastructural specializations during the formation of acetylcholine receptor aggregates on cultured myotubes.

    PubMed

    Olek, A J; Ling, A; Daniels, M P

    1986-02-01

    The ultrastructure of cultured rat myotubes was examined at stages in the initial assembly of acetylcholine receptor (AChR) aggregates in order to elucidate the role of cell-surface specializations in aggregate formation. Within 4-6 hr, embryonic brain extract (EBX) induces the formation of sites of AChR density elevated 5-9 X above that of surrounding regions, and the appearance of these aggregates is preceded by the formation of clouds of punctate microaggregates (Olek et al., 1983). A video image-intensification system was used to monitor this redistribution of fluorescently labeled AChR, and sites of aggregation were mapped on identified myotubes. After processing the cultures for electron microscopy, thin sections were taken through identified aggregate sites at various stages in assembly. Specializations, including a basal lamina, mound-shaped plasma membrane contours with occasional deep infoldings, and a subjacent dense cytoskeletal specialization, which tended to exclude other cytoplasmic organelles, were associated with newly formed aggregates found 4-6 hr after adding EBX to the cultures. Analysis of random thin sections through EBX-treated and untreated myotubes showed that the extent of specializations of the basal lamina and cytoplasm was approximately threefold greater in cells exposed to EBX for 4 hr, suggesting a concurrent, and possibly interdependent, organization of such specializations with AChR aggregate assembly. Examination of sections through clouds of microaggregates, which formed within 90 min, revealed mound-shaped plasma membrane contours and underlying cytoplasm depleted of organelles but relatively little basal lamina and submembrane cytoskeletal density. These results suggest that the initial stage of AChR aggregate assembly involves relatively subtle changes in the structure of the cell cortex and that the evolution of microaggregates to aggregates may require the formation of additional cytoskeletal and extracellular matrix

  5. Practical Power System Aggregation Considering Dynamic Loads

    NASA Astrophysics Data System (ADS)

    Yamagishi, Yoshio; Komami, Shintaro

    This paper presents a practical method for creating power system equivalents that can be used in power system stability analysis. The proposed method uses three branches to connect the boundary bus, generator, and load. The method is suitable to consider reactance from the boundary bus to the load for power system stability studies using a dynamic load model. Furthermore, this paper presents a practical procedure to determine the parameters of the aggregated generator, including control devices such as excitation systems, PSS (power system stabilizer), and speed governors. The quality of the various aggregation models is verified using power system stability simulations.

  6. Cultural Consensus Theory: Aggregating Continuous Responses in a Finite Interval

    NASA Astrophysics Data System (ADS)

    Batchelder, William H.; Strashny, Alex; Romney, A. Kimball

    Cultural consensus theory (CCT) consists of cognitive models for aggregating responses of "informants" to test items about some domain of their shared cultural knowledge. This paper develops a CCT model for items requiring bounded numerical responses, e.g. probability estimates, confidence judgments, or similarity judgments. The model assumes that each item generates a latent random representation in each informant, with mean equal to the consensus answer and variance depending jointly on the informant and the location of the consensus answer. The manifest responses may reflect biases of the informants. Markov Chain Monte Carlo (MCMC) methods were used to estimate the model, and simulation studies validated the approach. The model was applied to an existing cross-cultural dataset involving native Japanese and English speakers judging the similarity of emotion terms. The results sharpened earlier studies that showed that both cultures appear to have very similar cognitive representations of emotion terms.

  7. 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…

  8. Fractal aggregates in tennis ball systems

    NASA Astrophysics Data System (ADS)

    Sabin, J.; Bandín, M.; Prieto, G.; Sarmiento, F.

    2009-09-01

    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 images of the cluster of balls, following Forrest and Witten's pioneering studies on the aggregation of smoke particles, to estimate their fractal dimension.

  9. Small file aggregation in a parallel computing system

    DOEpatents

    Faibish, Sorin; Bent, John M.; Tzelnic, Percy; Grider, Gary; Zhang, Jingwang

    2014-09-02

    Techniques are provided for small file aggregation in a parallel computing system. An exemplary method for storing a plurality of files generated by a plurality of processes in a parallel computing system comprises aggregating the plurality of files into a single aggregated file; and generating metadata for the single aggregated file. The metadata comprises an offset and a length of each of the plurality of files in the single aggregated file. The metadata can be used to unpack one or more of the files from the single aggregated file.

  10. Aggregation Pheromone System: A Real-parameter Optimization Algorithm using Aggregation Pheromones as the Base Metaphor

    NASA Astrophysics Data System (ADS)

    Tsutsui, Shigeyosi

    This paper proposes an aggregation pheromone system (APS) for solving real-parameter optimization problems using the collective behavior of individuals which communicate using aggregation pheromones. APS was tested on several test functions used in evolutionary computation. The results showed APS could solve real-parameter optimization problems fairly well. The sensitivity analysis of control parameters of APS is also studied.

  11. A microwell cell culture platform for the aggregation of pancreatic β-cells.

    PubMed

    Bernard, Abigail B; Lin, Chien-Chi; Anseth, Kristi S

    2012-08-01

    Cell-cell contact between pancreatic β-cells is important for maintaining survival and normal insulin secretion. Various techniques have been developed to promote cell-cell contact between β-cells, but a simple yet robust method that affords precise control over three-dimensional (3D) β-cell cluster size has not been demonstrated. To address this need, we developed a poly(ethylene glycol) (PEG) hydrogel microwell platform using photolithography. This microwell cell-culture platform promotes the formation of 3D β-cell aggregates of defined sizes from 25 to 210 μm in diameter. Using this platform, mouse insulinoma 6 (MIN6) β-cells formed aggregates with cell-cell adherin junctions. These naturally formed cell aggregates with controllable sizes can be removed from the microwells for macroencapsulation, implantation, or other biological assays. When removed and subsequently encapsulated in PEG hydrogels, the aggregated cell clusters demonstrated improved cellular viability (>90%) over 7 days in culture, while the β-cells encapsulated as single cells maintained only 20% viability. Aggregated MIN6 cells also exhibited more than fourfold higher insulin secretion in response to a glucose challenge compared with encapsulated single β-cells. Further, the cell aggregates stained positively for E-cadherin, indicative of the formation of cell junctions. Using this hydrogel microwell cell-culture method, viable and functional β-cell aggregates of specific sizes were created, providing a platform from which other biologically relevant questions may be answered. PMID:22320435

  12. A Microwell Cell Culture Platform for the Aggregation of Pancreatic β-Cells

    PubMed Central

    Bernard, Abigail B.; Lin, Chien-Chi

    2012-01-01

    Cell–cell contact between pancreatic β-cells is important for maintaining survival and normal insulin secretion. Various techniques have been developed to promote cell–cell contact between β-cells, but a simple yet robust method that affords precise control over three-dimensional (3D) β-cell cluster size has not been demonstrated. To address this need, we developed a poly(ethylene glycol) (PEG) hydrogel microwell platform using photolithography. This microwell cell-culture platform promotes the formation of 3D β-cell aggregates of defined sizes from 25 to 210 μm in diameter. Using this platform, mouse insulinoma 6 (MIN6) β-cells formed aggregates with cell–cell adherin junctions. These naturally formed cell aggregates with controllable sizes can be removed from the microwells for macroencapsulation, implantation, or other biological assays. When removed and subsequently encapsulated in PEG hydrogels, the aggregated cell clusters demonstrated improved cellular viability (>90%) over 7 days in culture, while the β-cells encapsulated as single cells maintained only 20% viability. Aggregated MIN6 cells also exhibited more than fourfold higher insulin secretion in response to a glucose challenge compared with encapsulated single β-cells. Further, the cell aggregates stained positively for E-cadherin, indicative of the formation of cell junctions. Using this hydrogel microwell cell-culture method, viable and functional β-cell aggregates of specific sizes were created, providing a platform from which other biologically relevant questions may be answered. PMID:22320435

  13. Inverse problem analysis of pluripotent stem cell aggregation dynamics in stirred-suspension cultures

    PubMed Central

    Rostami, Mahboubeh Rahmati; Wu, Jincheng; Tzanakakis, Emmanuel S.

    2015-01-01

    The cultivation of stem cells as aggregates in scalable bioreactor cultures is an appealing modality for the large-scale manufacturing of stem cell products. Aggregation phenomena are central to such bioprocesses affecting the viability, proliferation and differentiation trajectory of stem cells but a quantitative framework is currently lacking. A population balance equation (PBE) model was used to describe the temporal evolution of the embryonic stem cell (ESC) cluster size distribution by considering collision-induced aggregation and cell proliferation in a stirred-suspension vessel. For ESC cultures at different agitation rates, the aggregation kernel representing the aggregation dynamics was successfully recovered as a solution of the inverse problem. The rate of change of the average aggregate size was greater at the intermediate rate tested suggesting a trade-off between increased collisions and agitation-induced shear. Results from forward simulation with obtained aggregation kernels were in agreement with transient aggregate size data from experiments. We conclude that the framework presented here can complement mechanistic studies offering insights into relevant stem cell clustering processes. More importantly from a process development standpoint, this strategy can be employed in the design and control of bioreactors for the generation of stem cell derivatives for drug screening, tissue engineering and regenerative medicine. PMID:26036699

  14. Inverse problem analysis of pluripotent stem cell aggregation dynamics in stirred-suspension cultures.

    PubMed

    Rostami, Mahboubeh Rahmati; Wu, Jincheng; Tzanakakis, Emmanuel S

    2015-08-20

    The cultivation of stem cells as aggregates in scalable bioreactor cultures is an appealing modality for the large-scale manufacturing of stem cell products. Aggregation phenomena are central to such bioprocesses affecting the viability, proliferation and differentiation trajectory of stem cells but a quantitative framework is currently lacking. A population balance equation (PBE) model was used to describe the temporal evolution of the embryonic stem cell (ESC) cluster size distribution by considering collision-induced aggregation and cell proliferation in a stirred-suspension vessel. For ESC cultures at different agitation rates, the aggregation kernel representing the aggregation dynamics was successfully recovered as a solution of the inverse problem. The rate of change of the average aggregate size was greater at the intermediate rate tested suggesting a trade-off between increased collisions and agitation-induced shear. Results from forward simulation with obtained aggregation kernels were in agreement with transient aggregate size data from experiments. We conclude that the framework presented here can complement mechanistic studies offering insights into relevant stem cell clustering processes. More importantly from a process development standpoint, this strategy can be employed in the design and control of bioreactors for the generation of stem cell derivatives for drug screening, tissue engineering and regenerative medicine.

  15. Aggregate formation and suspension culture of human pluripotent stem cells and differentiated progeny.

    PubMed

    Hookway, Tracy A; Butts, Jessica C; Lee, Emily; Tang, Hengli; McDevitt, Todd C

    2016-05-15

    Culture of human pluripotent stem cells (hPSC) as in vitro multicellular aggregates has been increasingly used as a method to model early embryonic development. Three-dimensional assemblies of hPSCs facilitate interactions between cells and their microenvironment to promote morphogenesis, analogous to the multicellular organization that accompanies embryogenesis. In this paper, we describe a method for reproducibly generating and maintaining populations of homogeneous three-dimensional hPSC aggregates using forced aggregation and rotary orbital suspension culture. We propose solutions to several challenges associated with the consistent formation and extended culture of cell spheroids generated from hPSCs and their differentiated progeny. Further, we provide examples to demonstrate how aggregation can be used as a tool to select specific subpopulations of cells to create homotypic spheroids, or as a means to introduce multiple cell types to create heterotypic tissue constructs. Finally, we demonstrate that the aggregation and rotary suspension method can be used to support culture and maintenance of hPSC-derived cell populations representing each of the three germ layers, underscoring the utility of this platform for culturing many different cell types. PMID:26658353

  16. Cultural Heritage Content Re-Use: An Aggregators's Point of View

    NASA Astrophysics Data System (ADS)

    Gavrilis, D.; Ioannides, M.; Theofanous, E.

    2015-08-01

    This paper introduces a use case of re-using aggregated and enriched metadata for the tourism creative industry. The MORe aggregation and enrichment framework is presented along with an example for enriching cultural heritage objects harvested from a number of Omeka repositories. The enriched content is then published both to the EU Digital Library Europeana (http://www.europeana.eu) and to an Elastic Search component that feeds a portal aimed at providing tourists with interesting information.

  17. Anaerobic thermophilic culture system

    DOEpatents

    Ljungdahl, Lars G.; Wiegel, Jurgen K. W.

    1981-01-01

    A mixed culture system of the newly discovered microorganism Thermoanaerobacter ethanolicus ATCC31550 and the microorganism Clostridium thermocellum ATCC31549 is described. In a mixed nutrient culture medium that contains cellulose, these microorganisms have been coupled and cultivated to efficiently ferment cellulose to produce recoverable quantities of ethanol under anaerobic, thermophilic conditions.

  18. Aggregated models for integrated distillation systems

    SciTech Connect

    Caballero, J.A.; Grossmann, I.E.

    1999-06-01

    In this work the authors present an aggregated representation for distillation columns that can be used in the synthesis of separation sequences with heat integration. A new aggregated model is first presented for the stripping and rectifying sections of individual distillation columns. This model is based on mass balances and equilibrium feasibility, expressed in terms of flows, inlet concentrations, and recoveries. The energy balance can then be decoupled from the mass balance, and the utilities can be calculated for each separation task. The proposed model is applied to three different superstructures: state task network, state equipment network, and an intermediate representation. The proposed model yields a lower bound to the vapor flow or to the total cost of the utilities. Performance of the different superstructure representations in terms of robustness and computational time is illustrated with several examples.

  19. 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

  20. 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.

  1. Coordinated aggregation in complex systems:. an interdisciplinary approach

    NASA Astrophysics Data System (ADS)

    Basios, V.; Nicolis, S. C.; Deneubourg, J. L.

    2016-09-01

    The study of the topic of guided aggregation in biology brings together decision making, collective motion and the dynamical interplay between individuals and groups. At the same time it meets statistical mechanics and the physics of complex systems in a new paradigmatic thinking. We propose a research platform for implementation and for undertaking systematic studies of coordinated aggregation, in a truly multi- and inter-disciplinary fashion.

  2. Culture systems: air quality.

    PubMed

    Thomas, Theodore

    2012-01-01

    Poor laboratory air quality is a known hazard to the culture of human gametes and embryos. Embryologists and chemists have employed analytical methods for identifying and measuring bulk and select air pollutants to assess the risk they pose to the embryo culture system. However, contaminant concentrations that result in gamete or embryotoxicity are poorly defined. Combating the ill effects of poor air quality requires an understanding of how toxicants can infiltrate the laboratory, the incubator, and ultimately the culture media. A further understanding of site-specific air quality can then lead to the consideration of laboratory design and management strategies that can minimize the deleterious effects that air contamination may have on early embryonic development in vitro.

  3. Reduced receptor aggregation and altered cytoskeleton in cultured myocytes after space-flight

    NASA Technical Reports Server (NTRS)

    Gruener, R.; Roberts, R.; Reitstetter, R.

    1994-01-01

    We carried out parallel experiments first on the slow clinostat and then in space-flight to examine the effects of altered gravity on the aggregation of the nicotinic acetylcholine receptors and the structure of the cytoskeleton in cultured Xenopus embryonic muscle cells. By examining the concordance between results from space flight and the clinostat, we tested whether the slow clinostat is a relevant simulation paradigm. Space-flown cells showed marked changes in the distribution and organization of actin filaments and had a reduced incidence of acetylcholine receptor aggregates at the site of contact with polystyrene beads. Similar effects were found after clinostat rotation. The sensitivity of synaptic receptor aggregation and cytoskeletal morphology suggests that in the microgravity of space cell behavior may be importantly altered.

  4. Tanshinones inhibit amyloid aggregation by amyloid-β peptide, disaggregate amyloid fibrils, and protect cultured cells.

    PubMed

    Wang, Qiuming; Yu, Xiang; Patal, Kunal; Hu, Rundong; Chuang, Steven; Zhang, Ge; Zheng, Jie

    2013-06-19

    The misfolding and aggregation of amyloid-β (Aβ) peptides into amyloid fibrils is regarded as one of the causative events in the pathogenesis of Alzheimer's disease (AD). Tanshinones extracted from Chinese herb Danshen (Salvia Miltiorrhiza Bunge) were traditionally used as anti-inflammation and cerebrovascular drugs due to their antioxidation and antiacetylcholinesterase effects. A number of studies have suggested that tanshinones could protect neuronal cells. In this work, we examine the inhibitory activity of tanshinone I (TS1) and tanshinone IIA (TS2), the two major components in the Danshen herb, on the aggregation and toxicity of Aβ1-42 using atomic force microscopy (AFM), thioflavin-T (ThT) fluorescence assay, cell viability assay, and molecular dynamics (MD) simulations. AFM and ThT results show that both TS1 and TS2 exhibit different inhibitory abilities to prevent unseeded amyloid fibril formation and to disaggregate preformed amyloid fibrils, in which TS1 shows better inhibitory potency than TS2. Live/dead assay further confirms that introduction of a very small amount of tanshinones enables protection of cultured SH-SY5Y cells against Aβ-induced cell toxicity. Comparative MD simulation results reveal a general tanshinone binding mode to prevent Aβ peptide association, showing that both TS1 and TS2 preferentially bind to a hydrophobic β-sheet groove formed by the C-terminal residues of I31-M35 and M35-V39 and several aromatic residues. Meanwhile, the differences in binding distribution, residues, sites, population, and affinity between TS1-Aβ and TS2-Aβ systems also interpret different inhibitory effects on Aβ aggregation as observed by in vitro experiments. More importantly, due to nonspecific binding mode of tanshinones, it is expected that tanshinones would have a general inhibitory efficacy of a wide range of amyloid peptides. These findings suggest that tanshinones, particularly TS1 compound, offer promising lead compounds with dual

  5. Thrombin action decreases acetylcholine receptor aggregate number and stability in cultured mouse myotubes.

    PubMed

    Davenport, R W; Lanuza, M; Kim, S; Jia, M; Snyder, E; Nelson, P G

    2000-08-30

    Neurons develop and make very stable, long-term synaptic connections with other nerve cells and with muscle. Synaptic stability at the neuromuscular junction changes over development in that a proliferation of synaptic input are made to individual myotubes and synapses from all but one neuron are lost during development. In an established co-culture paradigm in which spinal motoneurons synaptically contact myotubes, thrombin and associated protease inhibitors have been shown to affect the loss of functional synaptic contacts [6]. Evidence has not been provided which clearly demonstrate whether protease/protease inhibitors affect either the pre- or postsynaptic terminal, or both. In an effort to determine whether these reagents directly affect postsynaptic receptors on myotubes, myotubes were cultured in the absence of neurons and the spontaneous presence and stability of aggregates of acetylcholine receptors (AChR) in control and thrombin-containing media were evaluated. In dishes fixed after treatment and in dishes in which individual aggregates were observed live, thrombin action appeared to increase loss of AChR aggregates over time. Hirudin, a specific inhibitor of the thrombin protease, diminished this loss. Neither reagent affected the overall incorporation or degradation of AChR; therefore, it appears these protease/protease inhibitors affect the state of AChR aggregation. PMID:10960680

  6. Manuals of Cultural Systems

    NASA Astrophysics Data System (ADS)

    Ballonoff, Paul

    2014-10-01

    Ethnography often studies social networks including empirical descriptions of marriages and families. We initially concentrate on a special subset of networks which we call configurations. We show that descriptions of the possible outcomes of viable histories form a manual, and an orthoalgebra. We then study cases where family sizes vary, and show that this also forms a manual. In fact, it demonstrates adiabatic invariance, a property often associated with physical system conservation laws, and which here expresses conservation of the viability of a cultural system.

  7. Aggregation and dendritic growth in a magnetic granular system

    NASA Astrophysics Data System (ADS)

    González-Gutiérrez, J.; Carrillo-Estrada, J. L.; Ruiz-Suárez, J. C.

    2013-12-01

    We experimentally study the aggregation of non-Brownian paramagnetic beads in a vibrofluidized system induced by an external magnetic dipole. A dendritic growth is observed in real time, particle by particle, and with the naked eye. Two aggregation stages are observed, where tip, tip-split and side-branching growths are differentiated. We found clusters morphologically similar to those generated by a diffusion limited aggregation algorithm (DLA). However, in our case, due to the finite range of the magnetic field, the clusters reach a finite size and their structures exhibit different rates of aggregation. These are revealed by the existence of two different scaling relations of the mass with the gyration radius, and the nature of the radial mass distribution function. The structures of the clusters are fractal objects with an effective mass fractal dimension of around 1.8. We found that an exponential function describes the aggregation phenomenon as a function of time. This exponential behavior is independent of the final state of the morphology (shape and length) of the agglomerates.

  8. 21 CFR 864.5700 - Automated platelet aggregation system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Automated platelet aggregation system. 864.5700 Section 864.5700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Automated and Semi-Automated Hematology...

  9. 21 CFR 864.5700 - Automated platelet aggregation system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automated platelet aggregation system. 864.5700 Section 864.5700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Automated and Semi-Automated Hematology...

  10. 21 CFR 864.5700 - Automated platelet aggregation system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Automated platelet aggregation system. 864.5700 Section 864.5700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Automated and Semi-Automated Hematology...

  11. 21 CFR 864.5700 - Automated platelet aggregation system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Automated platelet aggregation system. 864.5700 Section 864.5700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Automated and Semi-Automated Hematology...

  12. 21 CFR 864.5700 - Automated platelet aggregation system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Automated platelet aggregation system. 864.5700 Section 864.5700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Automated and Semi-Automated Hematology...

  13. A Method of Data Aggregation for Wearable Sensor Systems.

    PubMed

    Shen, Bo; Fu, Jun-Song

    2016-06-23

    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.

  14. 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

  15. 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

  16. Association of heterotrophic bacteria with aggregated Arthrospira platensis exopolysaccharides: implications in the induction of axenic cultures.

    PubMed

    Shiraishi, Hideaki

    2015-01-01

    Inducing an axenic culture of the edible cyanobacterium Arthrospira (Spirulina) platensis using differential filtration alone is never successful; thus, it has been thought that, in non-axenic cultures, a portion of contaminating bacteria is strongly associated with Arthrospira cells. However, examination of the behavior of these bacteria during filtration revealed that they were not associated with Arthrospira cells but with aggregates of exopolysaccharides present in the medium away from the Arthrospira cells. Based on this finding, a rapid and reliable method for preparing axenic trichomes of A. platensis was established. After verifying the axenicity of the resulting trichomes on enriched agar plates, they were individually transferred to fresh sterile medium using a handmade tool, a microtrowel, to produce axenic cultures. With this technique, axenic cultures of various A. platensis strains were successfully produced. The technique described in this study is potentially applicable to a wider range of filamentous cyanobacteria. PMID:25333502

  17. Optimization and comparison of two different 3D culture methods to prepare cell aggregates as a bioink for organ printing.

    PubMed

    Imani, Rana; Hojjati Emami, Shahriar; Fakhrzadeh, Hossein; Baheiraei, Nafiseh; Sharifi, Ali M

    2012-04-01

    The ultimate goal of tissue engineering is to design and fabricate functional human tissues that are similar to natural cells and are capable of regeneration. Preparation of cell aggregates is one of the important steps in 3D tissue engineering technology, particularly in organ printing. Two simple methods, hanging drop (HD) and conical tube (CT) were utilized to prepare cell aggregates. The size and viability of the aggregates obtained at different initial cell densities and pre-culture duration were compared. The proliferative ability of the cell aggregates and their ability to spread in culture plates were also investigated. In both methods, the optimum average size of the aggregates was less than 500 microm. CT aggregates were smaller than HD aggregates. 5,000 cells per drop HD aggregates showed a marked ability to attach and spread on the culture surface. The proliferative ability reduced when the initial cell density was increased. Comparing these methods, we found that the HD method having better size controlling ability as well as enhanced ability to maintain higher rates of viability, spreading, and proliferation. In conclusion, smaller HD aggregates might be a suitable choice as building blocks for making bioink particles in bioprinting technique.

  18. Spheroidal aggregate culture of rat liver cells: histotypic reorganization, biomatrix deposition, and maintenance of functional activities

    PubMed Central

    1985-01-01

    Liver cells isolated from newborn rats and seeded on a non-adherent plastic substratum were found to spontaneously re-aggregate and to form, within a few days, spheroidal aggregates that eventually reached a plateaued diameter of 150-175 micron. Analyses on frozen sections from these spheroids by immunofluorescence microscopy using antibodies to various cytoskeletal elements and extracellular matrix components revealed a sorting out and a histotypic reorganization of three major cell types. A first type consisted of cells that segregated out on the aggregate surface forming a monolayer cell lining; a second type was identified as hepatocytes that regrouped in small islands often defining a central lumen; and a third group of cells reorganized into bile duct-like structures. This intercellular organization in the aggregates was paralleled by the accumulation of extracellular matrix components (laminin, fibronectin, and collagen) and their deposition following a specific pattern around each cell population structure. Determinations of albumin secretion and tyrosine aminotransferase induction by dexamethasone and glucagon at various times after the initiation of the cultures revealed a maintenance of the hepatocyte- differentiated functions for at least up to 2 mo at the levels measured at 3-5 d. It is concluded that cells dispersed as single cells from newborn rat liver conserve in part the necessary information to reconstruct a proper three-dimensional cyto-architecture and that the microenvironment so generated most likely represents a basic requirement for the optimal functioning of these differentiated cells. PMID:2411740

  19. Culture and Social Systems Revisited

    ERIC Educational Resources Information Center

    Parsons, Talcott

    1972-01-01

    A brief statement of the history of the relation between culture concepts is given, then, proceeding on the assumption that all human societies are interpenetrated with culture, the author attempts a relatively systematic outline of the structure of cultural systems and of their modes of articulation in social systems. (JB)

  20. Convex aggregative modelling of infinite memory nonlinear systems

    NASA Astrophysics Data System (ADS)

    Wachel, Paweł

    2016-08-01

    The convex aggregation technique is applied for modelling general class of nonlinear systems with unknown structure and infinite memory. The finite sample size properties of the algorithm are formally established and compared to the standard least-squares counterpart of the method. The proposed algorithm demonstrates its advantages when the a-priori knowledge and the measurement data are both scarce, that is, when the information about the actual system structure is unknown or uncertain and the measurement set is small and disturbed by a noise. Numerical experiments illustrate application and practical benefits of the method for various nonlinear systems.

  1. An Intracellular Arrangement of Histoplasma capsulatum Yeast-Aggregates Generates Nuclear Damage to the Cultured Murine Alveolar Macrophages

    PubMed Central

    Pitangui, Nayla de Souza; Sardi, Janaina de Cássia Orlandi; Voltan, Aline R.; dos Santos, Claudia T.; da Silva, Julhiany de Fátima; da Silva, Rosangela A. M.; Souza, Felipe O.; Soares, Christiane P.; Rodríguez-Arellanes, Gabriela; Taylor, Maria Lucia; Mendes-Giannini, Maria J. S.; Fusco-Almeida, Ana M.

    2016-01-01

    Histoplasma capsulatum is responsible for a human systemic mycosis that primarily affects lung tissue. Macrophages are the major effector cells in humans that respond to the fungus, and the development of respiratory disease depends on the ability of Histoplasma yeast cells to survive and replicate within alveolar macrophages. Therefore, the interaction between macrophages and H. capsulatum is a decisive step in the yeast dissemination into host tissues. Although the role played by components of cell-mediated immunity in the host's defense system and the mechanisms used by the pathogen to evade the host immune response are well understood, knowledge regarding the effects induced by H. capsulatum in host cells at the nuclear level is limited. According to the present findings, H. capsulatum yeast cells display a unique architectural arrangement during the intracellular infection of cultured murine alveolar macrophages, characterized as a formation of aggregates that seem to surround the host cell nucleus, resembling a “crown.” This extranuclear organization of yeast-aggregates generates damage on the nucleus of the host cell, producing DNA fragmentation and inducing apoptosis, even though the yeast cells are not located inside the nucleus and do not trigger changes in nuclear proteins. The current study highlights a singular intracellular arrangement of H. capsulatum yeast near to the nucleus of infected murine alveolar macrophages that may contribute to the yeast's persistence under intracellular conditions, since this fungal pathogen may display different strategies to prevent elimination by the host's phagocytic mechanisms. PMID:26793172

  2. Early stages in the formation and stabilization of acetylcholine receptor aggregates on cultured myotubes: sensitivity to temperature and azide.

    PubMed

    Olek, A J; Krikorian, J G; Daniels, M P

    1986-09-01

    We have studied the effects of temperature and sodium azide on the formation and stability of embryonic brain extract (EBX)2-induced acetylcholine receptor (AChR) aggregates on myotubes. Sequential changes in AChR distribution were studied on living myotubes in culture by video-intensified fluorescence microscopy. Aggregate formation was temperature dependent, increasing sharply from 24-36 degrees, maximal at 36-37 degrees, and virtually blocked at 38-40 degrees. Whereas aggregate size increased rapidly with time (up to 4 hr) at 36 degrees, at 18-24 degrees small (less than or equal to 1 micron) "microaggregates" formed and accumulated for up to 10 hr. Aggregates formed within 1.5 hr at the sites of microaggregates (formed after 4 hr at 23 degrees) if the temperature was raised to 36 degrees. However, if EBX was removed, the microaggregates on 50% of myotubes disassembled within 1.5 hr. The formation of microaggregates at 23 degrees and aggregates at 36 degrees was reversibly inhibited by sodium azide. These results show that clusters of microaggregates are the precursors of aggregates, and suggest that microaggregate clouds represent a discrete, labile, ATP-dependent stage in aggregate formation. Aggregates that had formed after 4 hr in the presence of EBX disassembled slowly (within 12-14 hr) following removal of EBX at 36 degrees, and even more slowly at 23-30 degrees. However, a temperature shift to 38 degrees, or the addition of azide, resulted in a rapid but reversible disassembly of aggregates (within 4 hr). Thus, newly formed aggregates appear to be relatively stable structures, while microaggregate clouds are labile, tending to disassemble or evolve into aggregates.

  3. Mass algal culture system

    DOEpatents

    Raymond, Lawrence P.

    1981-01-01

    An apparatus and process for the culture of algae in a liquid medium is disclosed. The medium circulates through an open trough and is exposed to an atmosphere which is temperature regulated. The nutrient content of the liquid medium is regulated to control the chemical composition growth and reproduction characteristics of the cultured algae. Before it is allowed to strike the medium, sunlight is passed through a filter to remove wavelengths which are not photosynthetically active. Heat energy can be recovered from the filter.

  4. Mass algal culture system

    DOEpatents

    Raymond, Lawrence P.

    1982-01-01

    An apparatus and process for the culture of algae in a liquid medium is disclosed. The medium circulates through an open trough and is exposed to an atmosphere which is temperature regulated. The nutrient content of the liquid medium is regulated to control the chemical composition growth and reproduction characteristics of the cultured algae. Before it is allowed to strike the medium, sunlight is passed through a filter to remove wavelengths which are not photosynthetically active. Heat energy can be recovered from the filter.

  5. Constraints on the Birth Aggregate of the Solar System

    NASA Astrophysics Data System (ADS)

    Adams, Fred C.; Laughlin, Gregory

    2001-03-01

    Using the observed properties of our Solar System, in particular the isotopic compositions of meteorites and the regularity of the planetary orbits, we constrain the star formation environment of the Sun within the scenario of (external) radioactive enrichment by a massive star. This calculation yields a probability distribution for the number of stars in the solar birth aggregate. The Sun is most likely to have formed within a stellar group containing N=< N>≈2000±1100 members. The a priori probability of a star forming in this type of environment is P≈0.0085; i.e., only about 1 out of 120 solar systems are expected to form under similar conditions. We discuss additional implications of this scenario, including possible effects from the radiation fields provided by the putative cluster environment and dynamical disruption of the Kuiper Belt. The constraints of this paper place tight restrictions on the properties of the solar birth aggregate for the scenario of external enrichment by a massive star; alternately, these tight constraints slightly favor a self-enrichment scenario for the short-lived radioactive species.

  6. Constraints on the Birth Aggregate of the Solar System

    NASA Astrophysics Data System (ADS)

    Adams, F. C.; Laughlin, G.

    2002-09-01

    Using the observed properties of our solar system -- the isotopic compositions of meteorites and the regularity of the planetary orbits -- we constrain the star formation environment of the Sun within the scenario of (external) radioactive enrichment by a massive star. This calculation yields a probability distribution for the number of stars in the solar birth aggregate. The Sun is most likely to have formed within a stellar group containing N=2000 members. The probability of a star forming in this type of environment is P = 0.0085, i.e., only about 1 out of 120 solar systems are expected to form under similar conditions. We discuss implications of this scenario, including possible effects from the radiation fields provided by the putative cluster environment and dynamical disruption of the Kuiper Belt. The constraints of this paper place tight restrictions on the properties of the solar birth aggregate for the scenario of external enrichment by a massive star; alternately, these tight constraints slightly favor a self-enrichment scenario for the short-lived radioactive species.

  7. High density cell culture system

    NASA Technical Reports Server (NTRS)

    Spaulding, Glenn F. (Inventor)

    1994-01-01

    An annular culture vessel for growing mammalian cells is constructed in a one piece integral and annular configuration with an open end which is closed by an endcap. The culture vessel is rotatable about a horizontal axis by use of conventional roller systems commonly used in culture laboratories. The end wall of the endcap has tapered access ports to frictionally and sealingly receive the ends of hypodermic syringes. The syringes permit the introduction of fresh nutrient and withdrawal of spent nutrients. The walls are made of conventional polymeric cell culture material and are subjected to neutron bombardment to form minute gas permeable perforations in the walls.

  8. Culture systems: embryo density.

    PubMed

    Reed, Michael L

    2012-01-01

    Embryo density is defined as the embryo-to-volume ratio achieved during in vitro culture; in other words, it is the number of embryos in a defined volume of culture medium. The same density can be achieved by manipulating either the number of embryos in a given volume of medium, or manipulating the volume of the medium for a given number of embryos: for example, a microdrop with five embryos in a 50 μl volume under oil has the same embryo-to-volume ratio (1:10 μl) as a microdrop with one embryo in a 10 μl volume under oil (1:10 μl). Increased embryo density can improve mammalian embryo development in vitro; however, the mechanism(s) responsible for this effect may be different with respect to which method is used to increase embryo density.Standard, flat sterile plastic petri dishes are the most common, traditional platform for embryo culture. Microdrops under a mineral oil overlay can be prepared to control embryo density, but it is critical that dish preparation is consistent, where appropriate techniques are applied to prevent microdrop dehydration during preparation, and results of any data collection are reliable, and repeatable. There are newer dishes available from several manufacturers that are specifically designed for embryo culture; most are readily available for use with human embryos. The concept behind these newer dishes relies on fabrication of conical and smaller volume wells into the dish design, so that embryos rest at the lowest point in the wells, and where putative embryotrophic factors may concentrate.Embryo density is not usually considered by the embryologist as a technique in and of itself; rather, the decision to culture embryos in groups or individually is protocol-driven, and is based more on convenience or the need to collect data on individual embryos. Embryo density can be controlled, and as such, it can be utilized as a simple, yet effective tool to improve in vitro development of human embryos. PMID:22829380

  9. Scattering and propagation of terahertz pulses in random soot aggregate systems

    NASA Astrophysics Data System (ADS)

    Li, Hai-Ying; Wu, Zhen-Sen; Bai, Lu; Li, Zheng-Jun

    2014-05-01

    Scattering and propagation of terahertz pulses in random soot aggregate systems are studied by using the generalized multi-particle Mie-solution (GMM) and the pulse propagation theory. Soot aggregates are obtained by the diffusion-limited aggregation (DLA) model. For a soot aggregate in soot aggregate systems, scattering characteristics are analyzed by using the GMM. Scattering intensities versus scattering angles are given. The effects of different positions of the aggregate on the scattering intensities, scattering cross sections, extinction cross sections, and absorption cross sections are computed and compared. Based on pulse propagation in random media, the transmission of terahertz pulses in random soot aggregate systems is determined by the two-frequency mutual coherence function. Numerical simulations and analysis are given for terahertz pulses (0.7956 THz).

  10. Multiple discrete soluble aggregates influence polyglutamine toxicity in a Huntington’s disease model system

    PubMed Central

    Xi, Wen; Wang, Xin; Laue, Thomas M.; Denis, Clyde L.

    2016-01-01

    Huntington’s disease (HD) results from expansions of polyglutamine stretches (polyQ) in the huntingtin protein (Htt) that promote protein aggregation, neurodegeneration, and death. Since the diversity and sizes of the soluble Htt-polyQ aggregates that have been linked to cytotoxicity are unknown, we investigated soluble Htt-polyQ aggregates using analytical ultracentrifugation. Soon after induction in a yeast HD model system, non-toxic Htt-25Q and cytotoxic Htt-103Q both formed soluble aggregates 29S to 200S in size. Because current models indicate that Htt-25Q does not form soluble aggregates, reevaluation of previous studies may be necessary. Only Htt-103Q aggregation behavior changed, however, with time. At 6 hr mid-sized aggregates (33S to 84S) and large aggregates (greater than 100S) became present while at 24 hr primarily only mid-sized aggregates (20S to 80S) existed. Multiple factors that decreased cytotoxicity of Htt-103Q (changing the length of or sequences adjacent to the polyQ, altering ploidy or chaperone dosage, or deleting anti-aging factors) altered the Htt-103Q aggregation pattern in which the suite of mid-sized aggregates at 6 hr were most correlative with cytotoxicity. Hence, the amelioration of HD and other neurodegenerative diseases may require increased attention to and discrimination of the dynamic alterations in soluble aggregation processes. PMID:27721444

  11. Method for Producing Non-Neoplastic, Three Dimensional, Mammalian Tissue and Cell Aggregates Under Microgravity Culture Conditions and the Products Produced Therefrom

    NASA Technical Reports Server (NTRS)

    Goodwin, Thomas J. (Inventor); Wolf, David A. (Inventor); Spaulding, Glenn F. (Inventor); Prewett, Tracey L. (Inventor)

    1996-01-01

    Normal mammalian tissue and the culturing process has been developed for the three groups of organ, structural, and blood tissue. The cells are grown in vitro under microgravity culture conditions and form three dimensional cells aggregates with normal cell function. The microgravity culture conditions may be microgravity or simulated microgravity created in a horizontal rotating wall culture vessel.

  12. Enzymatically degradable poly(ethylene glycol) hydrogels for the 3D culture and release of human embryonic stem cell derived pancreatic precursor cell aggregates.

    PubMed

    Amer, Luke D; Holtzinger, Audrey; Keller, Gordon; Mahoney, Melissa J; Bryant, Stephanie J

    2015-08-01

    This study aimed to develop a three dimensional culture platform for aggregates of human embryonic stem cell (hESC)-derived pancreatic progenitors that enables long-term culture, maintains aggregate size and morphology, does not adversely affect differentiation and provides a means for aggregate recovery. A platform was developed with poly(ethylene glycol) hydrogels containing collagen type I, for cell-matrix interactions, and peptide crosslinkers, for facile recovery of aggregates. The platform was first demonstrated with RIN-m5F cells, showing encapsulation and subsequent release of single cells and aggregates without adversely affecting viability. Aggregates of hESC-derived pancreatic progenitors with an effective diameter of 82 (15)μm were either encapsulated in hydrogels or cultured in suspension for 28 days. At day 14, aggregate viability was maintained in the hydrogels, but significantly reduced (88%) in suspension culture. However by day 28, viability was reduced under both culture conditions. Aggregate size was maintained in the hydrogels, but in suspension was significantly higher (∼ 2-fold) by day 28. The ability to release aggregates followed by a second enzyme treatment to achieve single cells enabled assessment by flow cytometry. Prior to encapsulation, there were 39% Pdx1(+)/Nkx6.1(+) cells, key endocrine markers required for β-cell maturation. The fraction of doubly positive cells was not affected in hydrogels but was slightly and significantly lower in suspension culture by 28 days. In conclusion, we demonstrate that a MMP-sensitive PEG hydrogel containing collagen type I is a promising platform for hESC-derived pancreatic progenitors that maintains viable aggregates, aggregate size, and progenitor state and offers facile recovery of aggregates.

  13. Enzymatically degradable poly(ethylene glycol) hydrogels for the 3D culture and release of human embryonic stem cell derived pancreatic precursor cell aggregates

    PubMed Central

    Amer, Luke D.; Holtzinger, Audrey; Keller, Gordon; Mahoney, Melissa J.; Bryant, Stephanie J.

    2015-01-01

    This study aimed to develop a three dimensional culture platform for aggregates of human embryonic stem cell (hESC)-derived pancreatic progenitors that enables long-term culture, maintains aggregate size and morphology, does not adversely affect differentiation and provides a means for aggregate recovery. A platform was developed with poly(ethylene glycol) hydrogels containing collagen type I, for cell-matrix interactions, and peptide crosslinkers, for facile recovery of aggregates. The platform was first demonstrated with RIN-m5F cells, showing encapsulation and subsequent release of single cells and aggregates without adversely affecting viability. Aggregates of hESC-derived pancreatic progenitors with an effective diameter of 82 (15) μm were either encapsulated in hydrogels or cultured in suspension for 28 days. At day 14, aggregate viability was maintained in the hydrogels, but significantly reduced (88%) in suspension culture. However by day 28, viability was reduced in both culture conditions. Aggregate size was maintained in the hydrogels, but in suspension was significantly higher (~2-fold) by day 28. The ability to release aggregates followed by a second enzyme treatment to achieve single cells enabled assessment by flow cytometry. Prior to encapsulation, there were 39% Pdx1+/Nkx6.1+ cells, key endocrine markers required for β-cell maturation. The fraction of doubly positive cells was not affected in hydrogels but was slightly and significantly lower in suspension culture by 28 days. In conclusion, we demonstrate that a MMP-sensitive PEG hydrogel containing collagen type I is a promising platform for hESC-derived pancreatic progenitors that maintains viable aggregates, aggregate size, and progenitor state and offers facile recovery of aggregates. PMID:25913222

  14. The A53E α-synuclein pathological mutation demonstrates reduced aggregation propensity in vitro and in cell culture.

    PubMed

    Rutherford, Nicola J; Giasson, Benoit I

    2015-06-15

    Mutations in the gene that encodes α-synuclein (αS) are a known cause of Parkinson's disease. αS is also the major component of pathological inclusions that characterize this disorder and a spectrum of other neurodegenerative diseases termed synucleinopathies. The effects of the most recently identified αS mutation, A53E, on αS aggregation were studied in vitro and in cell culture models. The A53E mutation in αS impedes the formation of aggregated, amyloid protein in vitro compared to wild-type αS. Under certain conditions, A53E αS can still form elongated amyloid fibrils with similar morphology, but with thinner width compared to wild-type αS. Using amyloid seeding of αS in cell culture studies, we demonstrate that significantly less A53E αS could be induced to aggregate compared to wild-type αS, although the mutant protein was still able to form mature inclusions within some cells. Furthermore, expression of A53E αS enhanced toxicity in cells experiencing mitochondrial stress. These findings indicate that the A53E mutation in αS reduces the propensity of αS to aggregate both in vitro and in the cellular environment, and may lead to cellular toxicity through other mechanisms.

  15. An online detection system for aggregate sizes and shapes based on digital image processing

    NASA Astrophysics Data System (ADS)

    Yang, Jianhong; Chen, Sijia

    2016-07-01

    Traditional aggregate size measuring methods are time-consuming, taxing, and do not deliver online measurements. A new online detection system for determining aggregate size and shape based on a digital camera with a charge-coupled device, and subsequent digital image processing, have been developed to overcome these problems. The system captures images of aggregates while falling and flat lying. Using these data, the particle size and shape distribution can be obtained in real time. Here, we calibrate this method using standard globules. Our experiments show that the maximum particle size distribution error was only 3 wt%, while the maximum particle shape distribution error was only 2 wt% for data derived from falling aggregates, having good dispersion. In contrast, the data for flat-lying aggregates had a maximum particle size distribution error of 12 wt%, and a maximum particle shape distribution error of 10 wt%; their accuracy was clearly lower than for falling aggregates. However, they performed well for single-graded aggregates, and did not require a dispersion device. Our system is low-cost and easy to install. It can successfully achieve online detection of aggregate size and shape with good reliability, and it has great potential for aggregate quality assurance.

  16. Culture systems: low-oxygen culture.

    PubMed

    Kovačič, Borut

    2012-01-01

    The tension of oxygen measured in the oviducts of several mammals was 5-8.7 %, but this drops in the uterine milieu to <2 % in cows and primates. For embryo culture in human in vitro fertilization (IVF), a non-physiologic level of 20 % oxygen has been used for the past 30 years. However, several animal studies have shown that low levels of oxygen plays an important physiological role in reducing the high levels of detrimental reactive oxygen species within cells, influences the embryonic gene expression, helps with embryo metabolism of glucose, and enhances embryo development to blastocysts. However, clinical studies have given contradictory results. Nevertheless, in nearly all reports, some kind of improvement has been observed, either in embryo development or in implantation and no detriments have been reported. For these reasons, more and more IVF laboratories utilize low oxygen during embryo culture.

  17. Culture systems: embryo culture and monozygotic twinning.

    PubMed

    Sparks, Amy E

    2012-01-01

    The incidence of monozygotic twinning in pregnancies achieved with assisted reproductive technologies (ART) is significantly higher than spontaneously conceived pregnancies. The factors associated with ART that predispose the embryos to splitting are not well-characterized. Assisted hatching and extended embryo culture are two ART laboratory methods that have been risk factors for monozygotic twinning. The methods and strategies that may be employed to avoid monozygotic twinning are discussed in this chapter.

  18. 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.

  19. The Thioredoxin System Protects Ribosomes against Stress-induced Aggregation

    PubMed Central

    Rand, Jonathan D.; Grant, Chris M.

    2006-01-01

    We previously showed that thioredoxins are required for dithiothreitol (DTT) tolerance, suggesting they maintain redox homeostasis in response to both oxidative and reductive stress conditions. In this present study, we screened the complete set of viable deletion strains in Saccharomyces cerevisiae for sensitivity to DTT to identify cell functions involved in resistance to reductive stress. We identified 195 mutants, whose gene products are localized throughout the cell. DTT-sensitive mutants were distributed among most major biological processes, but they particularly affected gene expression, metabolism, and the secretory pathway. Strikingly, a mutant lacking TSA1, encoding a peroxiredoxin, showed a similar sensitivity to DTT as a thioredoxin mutant. Epistasis analysis indicated that thioredoxins function upstream of Tsa1 in providing tolerance to DTT. Our data show that the chaperone function of Tsa1, rather than its peroxidase function, is required for this activity. Cells lacking TSA1 were found to accumulate aggregated proteins, and this was exacerbated by exposure to DTT. Analysis of the protein aggregates revealed that they are predominantly composed of ribosomal proteins. Furthermore, aggregation was found to correlate with an inhibition of translation initiation. We propose that Tsa1 normally functions to chaperone misassembled ribosomal proteins, preventing the toxicity that arises from their aggregation. PMID:16251355

  20. Arginine–glycine–aspartic acid–polyethylene glycol–polyamidoamine dendrimer conjugate improves liver-cell aggregation and function in 3-D spheroid culture

    PubMed Central

    Chen, Zhanfei; Lian, Fen; Wang, Xiaoqian; Chen, Yanling; Tang, Nanhong

    2016-01-01

    The polyamidoamine (PAMAM) dendrimer, a type of macromolecule material, has been used in spheroidal cell culture and drug delivery in recent years. However, PAMAM is not involved in the study of hepatic cell-spheroid culture or its biological activity, particularly in detoxification function. Here, we constructed a PAMAM-dendrimer conjugate decorated by an integrin ligand: arginine–glycine–aspartic acid (RGD) peptide. Our studies demonstrate that RGD–polyethylene glycol (PEG)–PAMAM conjugates can promote singly floating hepatic cells to aggregate together in a sphere-like growth with a weak reactive oxygen species. Moreover, RGD-PEG-PAMAM conjugates can activate the AKT–MAPK pathway in hepatic cells to promote cell proliferation and improve basic function and ammonia metabolism. Together, our data support the hepatocyte sphere treated by RGD-PEG-PAMAM conjugates as a potential source of hepatic cells for a biological artificial liver system.

  1. Arginine-glycine-aspartic acid-polyethylene glycol-polyamidoamine dendrimer conjugate improves liver-cell aggregation and function in 3-D spheroid culture.

    PubMed

    Chen, Zhanfei; Lian, Fen; Wang, Xiaoqian; Chen, Yanling; Tang, Nanhong

    2016-01-01

    The polyamidoamine (PAMAM) dendrimer, a type of macromolecule material, has been used in spheroidal cell culture and drug delivery in recent years. However, PAMAM is not involved in the study of hepatic cell-spheroid culture or its biological activity, particularly in detoxification function. Here, we constructed a PAMAM-dendrimer conjugate decorated by an integrin ligand: arginine-glycine-aspartic acid (RGD) peptide. Our studies demonstrate that RGD-polyethylene glycol (PEG)-PAMAM conjugates can promote singly floating hepatic cells to aggregate together in a sphere-like growth with a weak reactive oxygen species. Moreover, RGD-PEG-PAMAM conjugates can activate the AKT-MAPK pathway in hepatic cells to promote cell proliferation and improve basic function and ammonia metabolism. Together, our data support the hepatocyte sphere treated by RGD-PEG-PAMAM conjugates as a potential source of hepatic cells for a biological artificial liver system. PMID:27621619

  2. Arginine–glycine–aspartic acid–polyethylene glycol–polyamidoamine dendrimer conjugate improves liver-cell aggregation and function in 3-D spheroid culture

    PubMed Central

    Chen, Zhanfei; Lian, Fen; Wang, Xiaoqian; Chen, Yanling; Tang, Nanhong

    2016-01-01

    The polyamidoamine (PAMAM) dendrimer, a type of macromolecule material, has been used in spheroidal cell culture and drug delivery in recent years. However, PAMAM is not involved in the study of hepatic cell-spheroid culture or its biological activity, particularly in detoxification function. Here, we constructed a PAMAM-dendrimer conjugate decorated by an integrin ligand: arginine–glycine–aspartic acid (RGD) peptide. Our studies demonstrate that RGD–polyethylene glycol (PEG)–PAMAM conjugates can promote singly floating hepatic cells to aggregate together in a sphere-like growth with a weak reactive oxygen species. Moreover, RGD-PEG-PAMAM conjugates can activate the AKT–MAPK pathway in hepatic cells to promote cell proliferation and improve basic function and ammonia metabolism. Together, our data support the hepatocyte sphere treated by RGD-PEG-PAMAM conjugates as a potential source of hepatic cells for a biological artificial liver system. PMID:27621619

  3. Positive and negative aggregation responses to cultured human tumor cell lines among different normal individuals.

    PubMed

    Bastida, E; Ordinas, A; Jamieson, G A

    1982-01-01

    Platelets from approximately 50% (7/16) of normal individuals have been shown to have greater sensitivity to aggregation induced by critical threshold concentrations of three human tumor cell lines. These results may have implications for the genetics and epidemiology of human neoplastic disease.

  4. Differentiation of mammalian skeletal muscle cells cultured on microcarrier beads in a rotating cell culture system

    NASA Technical Reports Server (NTRS)

    Torgan, C. E.; Burge, S. S.; Collinsworth, A. M.; Truskey, G. A.; Kraus, W. E.

    2000-01-01

    The growth and repair of adult skeletal muscle are due in part to activation of muscle precursor cells, commonly known as satellite cells or myoblasts. These cells are responsive to a variety of environmental cues, including mechanical stimuli. The overall goal of the research is to examine the role of mechanical signalling mechanisms in muscle growth and plasticity through utilisation of cell culture systems where other potential signalling pathways (i.e. chemical and electrical stimuli) are controlled. To explore the effects of decreased mechanical loading on muscle differentiation, mammalian myoblasts are cultured in a bioreactor (rotating cell culture system), a model that has been utilised to simulate microgravity. C2C12 murine myoblasts are cultured on microcarrier beads in a bioreactor and followed throughout differentiation as they form a network of multinucleated myotubes. In comparison with three-dimensional control cultures that consist of myoblasts cultured on microcarrier beads in teflon bags, myoblasts cultured in the bioreactor exhibit an attenuation in differentiation. This is demonstrated by reduced immunohistochemical staining for myogenin and alpha-actinin. Western analysis shows a decrease, in bioreactor cultures compared with control cultures, in levels of the contractile proteins myosin (47% decrease, p < 0.01) and tropomyosin (63% decrease, p < 0.01). Hydrodynamic measurements indicate that the decrease in differentiation may be due, at least in part, to fluid stresses acting on the myotubes. In addition, constraints on aggregate size imposed by the action of fluid forces in the bioreactor affect differentiation. These results may have implications for muscle growth and repair during spaceflight.

  5. Delta-9-tetrahydrocannabinol accumulation, metabolism and cell-type-specific adverse effects in aggregating brain cell cultures

    SciTech Connect

    Monnet-Tschudi, Florianne Hazekamp, Arno; Perret, Nicolas; Zurich, Marie-Gabrielle; Mangin, Patrice; Giroud, Christian; Honegger, Paul

    2008-04-01

    Despite the widespread use of Cannabis as recreational drug or as medicine, little is known about its toxicity. The accumulation, metabolism and toxicity of THC were analyzed 10 days after a single treatment, and after repeated exposures during 10 days. Mixed-cell aggregate cultures of fetal rat telencephalon were used as in vitro model, as well as aggregates enriched either in neurons or in glial cells. It was found that THC accumulated preferentially in neurons, and that glia-neuron interactions decreased THC accumulation. The quantification of 11-OH-THC and of THC-COOH showed that brain aggregates were capable of THC metabolism. No cell-type difference was found for the metabolite 11-OH-THC, whereas the THC-COOH content was higher in mixed-cell cultures. No cell death was found at THC concentrations of 2 {mu}M in single treatment and of 1 {mu}M and 2 {mu}M in repeated treatments. Neurons, and particularly GABAergic neurons, were most sensitive to THC. Only the GABAergic marker was affected after the single treatment, whereas the GABAergic, cholinergic and astrocytic markers were decreased after the repeated treatments. JWH 015, a CB2 receptor agonist, showed effects similar to THC, whereas ACEA, a CB1 receptor agonist, had no effect. The expression of the cytokine IL-6 was upregulated 48 h after the single treatment with 5 {mu}M of THC or JWH 015, whereas the expression of TNF-{alpha} remained unchanged. These results suggest that the adverse effects of THC were related either to THC accumulation or to cannabinoid receptor activation and associated with IL-6 upregulation.

  6. Impacts of Cropping Systems on Aggregates Associated Organic Carbon and Nitrogen in a Semiarid Highland Agroecosystem

    PubMed Central

    Chu, Jiashu; Zhang, Tianzhe; Chang, Weidong; Zhang, Dan; Zulfiqar, Saman; Fu, Aigen; Hao, Yaqi

    2016-01-01

    The effect of cropping system on the distribution of organic carbon (OC) and nitrogen (N) in soil aggregates has not been well addressed, which is important for understanding the sequestration of OC and N in agricultural soils. We analyzed the distribution of OC and N associated with soil aggregates in three unfertilized cropping systems in a 27-year field experiment: continuously cropped alfalfa, continuously cropped wheat and a legume-grain rotation. The objectives were to understand the effect of cropping system on the distribution of OC and N in aggregates and to examine the relationships between the changes in OC and N stocks in total soils and in aggregates. The cropping systems increased the stocks of OC and N in total soils (0–40 cm) at mean rates of 15.6 g OC m-2 yr-1 and 1.2 g N m-2 yr-1 relative to a fallow control. The continuous cropping of alfalfa produced the largest increases at the 0–20 cm depth. The OC and N stocks in total soils were significantly correlated with the changes in the >0.053 mm aggregates. 27-year of cropping increased OC stocks in the >0.053 mm size class of aggregates and N stocks in the >0.25 mm size class but decreased OC stocks in the <0.053 mm size class and N stocks in the <0.25 mm size class. The increases in OC and N stocks in these aggregates accounted for 99.5 and 98.7% of the total increases, respectively, in the continuous alfalfa system. The increases in the OC and N stocks associated with the >0.25 mm aggregate size class accounted for more than 97% of the total increases in the continuous wheat and the legume-grain rotation systems. These results suggested that long-term cropping has the potential to sequester OC and N in soils and that the increases in soil OC and N stocks were mainly due to increases associated with aggregates >0.053 mm. PMID:27764209

  7. Phase transition analogous to Bose-Einstein condensation in systems of noninteracting surfactant aggregates

    NASA Astrophysics Data System (ADS)

    Cuesta, José A.; Sear, Richard P.

    2002-03-01

    Ideal bosons and a classical system of monomers that aggregate forming noninteracting ring polymers are known to have the same partition function. So, the ring polymers have a phase transition, the analogue of Bose-Einstein condensation of bosons. At this phase transition macroscopic polymers are formed. The link between these systems is made via Feynman's path integrals: these integrals are the same for the trajectories of the bosons in imaginary time and for the configurations of the polymers. We show that a transition of this general form occurs within a whole class of aggregating systems. Examples are the lamellae formation in suspensions of disclike micelles or the emulsification failure observed in water-oil-surfactant emulsions. As with bosons, the transition occurs even when aggregates do not interact. The λ-transition in 4He is believed to be Bose-Einstein condensation modified by interatomic interactions. We suggest that interaggregate interactions too only modify the transition we have found.

  8. Copper nanoparticles generated from aggregates of a hexarylbenzene derivative: a reusable catalytic system for 'click' reactions.

    PubMed

    Kaur, Sharanjeet; Bhalla, Vandana; Kumar, Manoj

    2015-01-11

    Fluorescent aggregates of hexarylbenzene derivative 3 have been utilized as reactors for the preparation of copper nanoparticles in aqueous medium, which serve as effective catalytic system for the alkyl-azide 'click' reaction to synthesize 1,2,3-triazoles in excellent yields under solvent-free conditions. This catalytic system can be recycled and reused five times without significant loss of catalytic activity.

  9. Enhanced effect of aggregated gold nanoparticles on luminol chemiluminescence system and its analytical application

    NASA Astrophysics Data System (ADS)

    Qi, Yingying; Li, Baoxin

    2013-07-01

    Some organic compounds containing groups of OH, NH2, or SH, which could induce the aggregation of gold nanoparticles (AuNPs), were observed to enhance effectively the luminol-H2O2-2.6 nm AuNPs CL system. It was found that the aggregation of AuNPs was an important effect factor for the catalytic activity of AuNPs on luminol CL system. The aggregated AuNPs could effectively enhance luminol CL signal compared with the dispersed one. The enhanced effect was closely related to the sizes of AuNPs. Among the studied AuNPs with seven sizes, 2.6 nm AuNPs had the greatest enhancement effect on luminol CL system after its aggregation. The CL enhancement mechanism was investigated, and the marked enhancement of aggregated 2.6 nm AuNPs for luminol CL system was supposed to originate from the decrease of AuNPs' surface negative charge density compared to its dispersed state. For the luminol-H2O2-2.6 nm AuNPs CL system in the presence of organic compounds containing groups of OH, NH2, or SH, more than one factor played the role in influencing the CL intensity. It was found that the enhanced effect of aggregated 2.6 nm AuNPs induced by such organic compounds was much more significant than the inhibition effect of reducing groups of OH, NH2, or SH, which made it applicable for the determination of this kind of compounds.

  10. Triiodothyronine expands the lactotroph and maintains the lactosomatotroph population, whereas thyrotrophin-releasing hormone augments thyrotroph abundance in aggregate cell cultures of postnatal rat pituitary gland.

    PubMed

    Pals, K; Vankelecom, H; Denef, C

    2006-03-01

    In the present study, we used a three-dimensional pituitary cell culture system from early postnatal rats to examine the in vitro developmental potential of triiodothyronine (T3) and thyrotrophin-releasing hormone (TRH). Cell types were identified at the hormone mRNA level by single-cell reverse transcription-polymerase chain reaction and any change in abundance was further examined by immunofluorescence staining of the corresponding hormone protein. In aggregates from 14-day-old rats, long-term (12-16 days) treatment with T3 (0.5 nM) increased the abundance of cells expressing prolactin mRNA (PRLmRNA cells) by 2.5-fold and lowered that of nonhormonal cells and thyroid-stimulating hormone beta (TSHbeta)mRNA cells. The abundance of growth hormone (GH)mRNA cells decreased during culture compared to that in the freshly dispersed pituitary gland and T3 did not significantly affect this cell population. Cells coexpressing PRL mRNA and GH mRNA virtually disappeared during culture but reappeared in the presence of T3. T3 increased the abundance of PRL-immunoreactive (ir) cells in aggregates from 14-day-old rats, as well as in aggregates from newborn and 1-week-old rats. As estimated by bromodeoxyuridine (BrdU) labelling, a 3-day treatment with T3 enhanced the number of PRL-ir cells that had incorporated BrdU, but did not yet expand the total population of PRL-ir cells. Long-term treatment with TRH (100 nM) did not affect the proportion of PRLmRNA or GHmRNA cells, but consistently increased the proportional number of TSHbeta(mRNA) and TSHbeta-ir cells. The present data confirm the findings obtained in recent in vivo loss of function genetic studies suggesting that T3 plays a prominent role in postnatal expansion of the lactotroph population and that TRH is important for thyrotroph development. The data suggest that the effect of T3 is brought about by a direct action on the pituitary gland through a cell proliferation mechanism. T3 also appears to support the

  11. The rich detail of cultural symbol systems.

    PubMed

    Read, Dwight W

    2014-08-01

    The goal of forming a science of intentional behavior requires a more richly detailed account of symbolic systems than is assumed by the authors. Cultural systems are not simply the equivalent in the ideational domain of culture of the purported Baldwin Effect in the genetic domain. PMID:25162879

  12. Studying the concentration dependence of the aggregation number of a micellar model system by SANS.

    PubMed

    Amann, Matthias; Willner, Lutz; Stellbrink, Jörg; Radulescu, Aurel; Richter, Dieter

    2015-06-01

    We present a small-angle neutron scattering (SANS) structural characterization of n-alkyl-PEO polymer micelles in aqueous solution with special focus on the dependence of the micellar aggregation number on increasing concentration. The single micellar properties in the dilute region up to the overlap concentration ϕ* are determined by exploiting the well characterized unimer exchange kinetics of the model system in a freezing and diluting experiment. The micellar solutions are brought to thermodynamic equilibrium at high temperatures, where unimer exchange is fast, and are then cooled to low temperatures and diluted to concentrations in the limit of infinite dilution. At low temperatures the kinetics, and therefore the key mechanism for micellar rearrangement, is frozen on the experimental time scale, thus preserving the micellar structure in the dilution process. Information about the single micellar structure in the semidilute and concentrated region are extracted from structure factor analysis at high concentrations where the micelles order into fcc and bcc close packed lattices and the aggregation number can be calculated by geometrical arguments. This approach enables us to investigate the aggregation behavior in a wide concentration regime from dilute to 6·ϕ*, showing a constant aggregation number with concentration over a large concentration regime up to a critical concentration about three times ϕ*. When exceeding this critical concentration, the aggregation number was found to increase with increasing concentration. This behavior is compared to scaling theories for star-like polymer micelles. PMID:25892401

  13. Studying the concentration dependence of the aggregation number of a micellar model system by SANS.

    PubMed

    Amann, Matthias; Willner, Lutz; Stellbrink, Jörg; Radulescu, Aurel; Richter, Dieter

    2015-06-01

    We present a small-angle neutron scattering (SANS) structural characterization of n-alkyl-PEO polymer micelles in aqueous solution with special focus on the dependence of the micellar aggregation number on increasing concentration. The single micellar properties in the dilute region up to the overlap concentration ϕ* are determined by exploiting the well characterized unimer exchange kinetics of the model system in a freezing and diluting experiment. The micellar solutions are brought to thermodynamic equilibrium at high temperatures, where unimer exchange is fast, and are then cooled to low temperatures and diluted to concentrations in the limit of infinite dilution. At low temperatures the kinetics, and therefore the key mechanism for micellar rearrangement, is frozen on the experimental time scale, thus preserving the micellar structure in the dilution process. Information about the single micellar structure in the semidilute and concentrated region are extracted from structure factor analysis at high concentrations where the micelles order into fcc and bcc close packed lattices and the aggregation number can be calculated by geometrical arguments. This approach enables us to investigate the aggregation behavior in a wide concentration regime from dilute to 6·ϕ*, showing a constant aggregation number with concentration over a large concentration regime up to a critical concentration about three times ϕ*. When exceeding this critical concentration, the aggregation number was found to increase with increasing concentration. This behavior is compared to scaling theories for star-like polymer micelles.

  14. MODELING THE INFLUENCE OF ACTIVE SUBSLAB DEPRESSURIZATION (ASD) SYSTEMS ON AIRFLOWS IN SUBSLAB AGGREGATE BEDS

    EPA Science Inventory

    A simple model is presented that allows the pressure difference in a subslab aggregate layer to be estimated as a function of radial distance from the central suction point of an active subslab depressurization system by knowing the average size, thickness, porosity, and permeabi...

  15. Breakage of the energy equipartition and aggregate formation in sheared system

    NASA Astrophysics Data System (ADS)

    Baibolatov, Y.; Spahn, F.

    2015-10-01

    In classical thermodynamics any mixture of gases with different masses with any sort of initial temperature differences tend to relax into a stationary state with a unique temperature along the whole system. But this is not true in case of granular mixtures, where energy is dissipated during each collision between particles. As a result, in a granular mixture of species with different masses, the system does not have a unique thermodynamic temperature but each species has its own temperature. This effect has been paid much attention recently [1, 2, 3]. Apart from the dissipative particle interaction, the main reason for this behaviour is due to the mass difference of the colliding particles, causing an asymmetric energy loss of particles. The loss of energy can be compensated by external heating of the system. In the case of planetary rings system, the role of heating is played by gravitational shear caused by the planet. In this work we consider the model consisting of identical spherical and adhesive particles. Although the constituents are identical, they can form aggregates and effectively create particles with larger masses. The differences in masses lead to different velocity dispersions (granular temperatures) of the aggregates. This interplay between heat transfer among aggregates and the distribution of the aggregate sizes under the gravitational shear is of crucial importance for the formulation of mean-field balance equations for the ring particle ensembles.

  16. Data Aggregation in Multi-Agent Systems in the Presence of Hybrid Faults

    ERIC Educational Resources Information Center

    Srinivasan, Satish Mahadevan

    2010-01-01

    Data Aggregation (DA) is a set of functions that provide components of a distributed system access to global information for purposes of network management and user services. With the diverse new capabilities that networks can provide, applicability of DA is growing. DA is useful in dealing with multi-value domain information and often requires…

  17. Enhancement of endothelial differentiation of adipose derived mesenchymal stem cells by a three-dimensional culture system of microwell.

    PubMed

    Qiu, Xuefeng; Zhang, Yanting; Zhao, Xiaozhi; Zhang, Shiwei; Wu, Jinhui; Guo, Hongqian; Hu, Yiqiao

    2015-01-01

    Adipose derived mesenchymal stem cells (AdMSCs) have been demonstrated to have ability to differentiate into several cell lineages, including endothelial cells. The low endothelial differentiation efficiency, however, limits further clinical application of AdMSCs for therapeutic angiogenesis. This study was designed to investigate the feasibility to promote endothelial differentiation efficacy of AdMSCs using microwell array as a 3-D culture system. AdMSCs aggregates were prepared using photocrosslinkable polyethylene glycol dimethacrylate (PEGDM) derived microwell. AdMSCs aggregated and formed well defined 3-D aggregates following seeding. The microwell was effective in regulating the size of AdMSCs aggregates with low variation. AdMSCs within the 3-D aggregates maintained the cell surface epitopes of AdMSCs with high viability. Endothelial growth medium was used to induce the in vitro endothelial differentiation of AdMSCs. Both gene expression results from real time PCR and protein expression data from immunofluorescent staining revealed that 3-D cultured aggregates significantly promote the endothelial differentiation efficacy of AdMSCs. AdMSCs or AdMSCs aggregates were injected into the subcutaneous space of nu/nu mice to investigate the endothelial differentiation in vivo. The immunofluorescent staining data indicated promoted endothelial differentiation of 3-D aggregates compared with 2-D AdMSCs. Aggregates dissociated cells were obtained by transferring 3-D aggregates onto the adherent surfaces. Cells dissociated from induced aggregates were still positive for endothelial specific markers and were able to form endothelial-like tube structures on matrigel, indicating the endothelial properties. We conclude that microwell is an ideal 3-D culture system for promoting endothelial differentiation efficacy of AdMSCs. PMID:25890756

  18. Effect of aggregated silver nanoparticles on luminol chemiluminescence system and its analytical application

    NASA Astrophysics Data System (ADS)

    Qi, Yingying; Li, Baoxin; Xiu, Furong

    2014-07-01

    We found that after silver nanoparticles (AgNPs) aggregated, its catalytic activity on luminol CL reaction obviously changed, and the change characteristic was closely related to the sizes of AgNPs. UV-visible spectra, X-ray photoelectron spectra, zeta potential and transmission electron microscopy studies were carried out to investigate the CL effect mechanism. The different CL responses of aggregated AgNPs with different size were suggested to be due to the two effects of quantum size and electron density in nanoparticle's conduction bands, and which one played a major role. The poisonous organic contaminants such as anilines, could induce the aggregation of AgNPs, were observed to affect effectively the luminol-H2O2-7 nm and 15 nm AgNPs CL systems and were detectable by use of a flow injection method with the enhanced or inhibited CL detection.

  19. Challenges in Scheduling Aggregation in CyberPhysical Information Processing Systems

    SciTech Connect

    Horey, James L; Lagesse, Brent J

    2011-01-01

    Data aggregation (a.k.a reduce operations) is an important element in information processing systems, including MapReduce clusters and cyberphysical networks. Unlike simple sensor networks, all the data in information processing systems must be eventually aggregated. Our goal is to lower overall latency in these systems by intelligently scheduling aggregation on intermediate routing nodes. Unlike previous models, our model explicitly takes into account link latency and computa- tion time. Our model also considers heterogeneous computing capabilities. In order to understand the potential challenges associated with constructing a distributed scheduler that minimizes la- tency, we ve developed a simulation of our model and tested the results of randomly scheduling nodes. Although these experiments were designed to provide data for a null-model, preliminary results have yielded a few interesting observations. We show that in cases where the computation time is larger than transmission time, in-network aggregation can have a large effect (reducing latency by 50% or more), but that naive scheduling can have a detrimental effect. Specifically, we show that when the root node (a.k.a the basestation) is faster than the other nodes, the latency can increase with increased coverage, and that these effects vary with the number of nodes present.

  20. Economic Systems: A Modular Approach. Cultural Anthropology.

    ERIC Educational Resources Information Center

    Kassebaum, Peter

    Designed for use as supplementary instructional material in a cultural anthropology course, this learning module uses a systems approach to allow students to see the connections and similarities which most cultural groups share on the basis of the type of economic organization that they exhibit. The module begins with a general discussion of…

  1. Constructing a High Density Cell Culture System

    NASA Technical Reports Server (NTRS)

    Spaulding, Glenn F. (Inventor)

    1996-01-01

    An annular culture vessel for growing mammalian cells is constructed in a one piece integral and annular configuration with an open end which is closed by an endcap. The culture vessel is rotatable about a horizontal axis by use of conventional roller systems commonly used in culture laboratories. The end wall of the endcap has tapered access ports to frictionally and sealingly receive the ends of hypodermic syringes. The syringes permit the introduction of fresh nutrient and withdrawal of spent nutrients. The walls are made of conventional polymeric cell culture material and are subjected to neutron bombardment to form minute gas permeable perforations in the walls.

  2. Normal and system lupus erythematosus red blood cell interactions studied by double trap optical tweezers: direct measurements of aggregation forces

    NASA Astrophysics Data System (ADS)

    Khokhlova, Maria D.; Lyubin, Eugeny V.; Zhdanov, Alexander G.; Rykova, Sophia Yu.; Sokolova, Irina A.; Fedyanin, Andrey A.

    2012-02-01

    Direct measurements of aggregation forces in piconewton range between two red blood cells in pair rouleau are performed under physiological conditions using double trap optical tweezers. Aggregation and disaggregation properties of healthy and pathologic (system lupus erythematosis) blood samples are analyzed. Strong difference in aggregation speed and behavior is revealed using the offered method which is proposed to be a promising tool for SLE monitoring at single cell level.

  3. α-Synuclein propagates from mouse brain to grafted dopaminergic neurons and seeds aggregation in cultured human cells

    PubMed Central

    Hansen, Christian; Angot, Elodie; Bergström, Ann-Louise; Steiner, Jennifer A.; Pieri, Laura; Paul, Gesine; Outeiro, Tiago F.; Melki, Ronald; Kallunki, Pekka; Fog, Karina; Li, Jia-Yi; Brundin, Patrik

    2011-01-01

    Post-mortem analyses of brains from patients with Parkinson disease who received fetal mesencephalic transplants show that α-synuclein–containing (α-syn–containing) Lewy bodies gradually appear in grafted neurons. Here, we explored whether intercellular transfer of α-syn from host to graft, followed by seeding of α-syn aggregation in recipient neurons, can contribute to this phenomenon. We assessed α-syn cell-to-cell transfer using microscopy, flow cytometry, and high-content screening in several coculture model systems. Coculturing cells engineered to express either GFP– or DsRed-tagged α-syn resulted in a gradual increase in double-labeled cells. Importantly, α-syn–GFP derived from 1 neuroblastoma cell line localized to red fluorescent aggregates in other cells expressing DsRed–α-syn, suggesting a seeding effect of transmitted α-syn. Extracellular α-syn was taken up by cells through endocytosis and interacted with intracellular α-syn. Next, following intracortical injection of recombinant α-syn in rats, we found neuronal uptake was attenuated by coinjection of an endocytosis inhibitor. Finally, we demonstrated in vivo transfer of α-syn between host cells and grafted dopaminergic neurons in mice overexpressing human α-syn. In summary, intercellularly transferred α-syn interacts with cytoplasmic α-syn and can propagate α-syn pathology. These results suggest that α-syn propagation is a key element in the progression of Parkinson disease pathology. PMID:21245577

  4. CEACAM1 mediates B cell aggregation in central nervous system autoimmunity.

    PubMed

    Rovituso, Damiano M; Scheffler, Laura; Wunsch, Marie; Kleinschnitz, Christoph; Dörck, Sebastian; Ulzheimer, Jochen; Bayas, Antonios; Steinman, Lawrence; Ergün, Süleyman; Kuerten, Stefanie

    2016-01-01

    B cell aggregates in the central nervous system (CNS) have been associated with rapid disease progression in patients with multiple sclerosis (MS). Here we demonstrate a key role of carcinoembryogenic antigen-related cell adhesion molecule1 (CEACAM1) in B cell aggregate formation in MS patients and a B cell-dependent mouse model of MS. CEACAM1 expression was increased on peripheral blood B cells and CEACAM1(+) B cells were present in brain infiltrates of MS patients. Administration of the anti-CEACAM1 antibody T84.1 was efficient in blocking aggregation of B cells derived from MS patients. Along these lines, application of the monoclonal anti-CEACAM1 antibody mCC1 was able to inhibit CNS B cell aggregate formation and significantly attenuated established MS-like disease in mice in the absence of any adverse effects. CEACAM1 was co-expressed with the regulator molecule T cell immunoglobulin and mucin domain -3 (TIM-3) on B cells, a novel molecule that has recently been described to induce anergy in T cells. Interestingly, elevated coexpression on B cells coincided with an autoreactive T helper cell phenotype in MS patients. Overall, these data identify CEACAM1 as a clinically highly interesting target in MS pathogenesis and open new therapeutic avenues for the treatment of the disease. PMID:27435215

  5. CEACAM1 mediates B cell aggregation in central nervous system autoimmunity

    PubMed Central

    Rovituso, Damiano M.; Scheffler, Laura; Wunsch, Marie; Dörck, Sebastian; Ulzheimer, Jochen; Bayas, Antonios; Steinman, Lawrence; Ergün, Süleyman; Kuerten, Stefanie

    2016-01-01

    B cell aggregates in the central nervous system (CNS) have been associated with rapid disease progression in patients with multiple sclerosis (MS). Here we demonstrate a key role of carcinoembryogenic antigen-related cell adhesion molecule1 (CEACAM1) in B cell aggregate formation in MS patients and a B cell-dependent mouse model of MS. CEACAM1 expression was increased on peripheral blood B cells and CEACAM1+ B cells were present in brain infiltrates of MS patients. Administration of the anti-CEACAM1 antibody T84.1 was efficient in blocking aggregation of B cells derived from MS patients. Along these lines, application of the monoclonal anti-CEACAM1 antibody mCC1 was able to inhibit CNS B cell aggregate formation and significantly attenuated established MS-like disease in mice in the absence of any adverse effects. CEACAM1 was co-expressed with the regulator molecule T cell immunoglobulin and mucin domain −3 (TIM-3) on B cells, a novel molecule that has recently been described to induce anergy in T cells. Interestingly, elevated coexpression on B cells coincided with an autoreactive T helper cell phenotype in MS patients. Overall, these data identify CEACAM1 as a clinically highly interesting target in MS pathogenesis and open new therapeutic avenues for the treatment of the disease. PMID:27435215

  6. Development of a pulmonary peptide delivery system using porous nanoparticle-aggregate particles for systemic application.

    PubMed

    Yang, Likai; Luo, Jing; Shi, Sanjun; Zhang, Qiang; Sun, Xun; Zhang, Zhirong; Gong, Tao

    2013-07-15

    As a non-invasive administration route, pulmonary peptide delivery for systemic application has shown great promise. However, many barriers exist that prevent effective peptide delivery. The use of porous nanoparticle-aggregate particles (PNAPs) is an excellent option because of their proper aerodynamic size and maximal deposition. However, in most cases, the spray drying heating process for PNAPs has been challenging in regard to maintaining peptide stability and activity. To overcome these issues, we developed a spray freeze-drying method for PNAP preparation. To solve the low entrapment efficiency problem of nanostructured lipid carriers, we used hydrophobic ion pair complexes to increase the lipophilicity of the peptide, thus increasing entrapment efficiency and drug loading. Here, we used a model peptide, octreotide acetate, for PNAP preparation, which has a high entrapment efficiency (>95%) and proper aerodynamic size (~3 μm). In addition, after intrapulmonary administration, we evaluated the pharmacokinetics and pharmacodynamics in a rat preventive hepatic ischemia-reperfusion injury model. Our in vivo data showed significantly increased area under the curve and improved plasma aspartate aminotransferase levels for our PNAP intrapulmonary delivery system vs. the clinically used octreotide acetate delivery via subcutaneous injection. Together, PNAPs may have great potential for carrying peptide drugs for pulmonary delivery.

  7. RBC aggregation based system for long-term photoplethysmography (PPG): new prospects for PPG applications

    NASA Astrophysics Data System (ADS)

    Shvartsman, Leonid D.; Tverskoy, Boris

    2015-03-01

    We present system for long-term continuous PPG monitoring, and physical model for PPG analysis. The system is based on ideology of light scattering modulated by the process of RBC aggregation. OXIRATE's system works in reflection geometry. The sensor is tiny, completely mobile phone compatible, it can be placed nearly everywhere on the body surface. These technical features allow all-night comfortable PPG monitoring that was performed and analyzed. We can define various sleep stages on the basis of different reproducible time-behavior of PPG signal. Our system of PPG monitoring was used also for reflection pulse oximetry and for extreme PPG studies, such as diving.

  8. The Relationship Between Carbon Input, Aggregation, and Soil Organic Carbon Stabilization in Sustainable Cropping Systems

    NASA Astrophysics Data System (ADS)

    Kong, A. Y.; Six, J.; Bryant, D. C.; Denison, R.; van Kessel, C.

    2003-12-01

    Approximately 10% of the earth's soil C is stored within agricultural soil ecosystems. Because farming systems hold promise for sequestering C, their sustainability, environmental impact, and potential role in mitigating rising atmospheric CO2 concentrations must be addressed. Our current challenges are to provide credible evidence that agricultural practices can sequester significant amounts of C and to quantify the mechanisms, capacity, and longevity of agricultural lands as C sinks. Agronomic practices that influence yield and, therefore, affect the proportion of crop residues returned to the soil (e.g. cover cropping, irrigation, fertilizer addition, and compost application) are likely to influence soil organic carbon (SOC). The objectives of this study were (1) to determine the influence of C input on C sequestration in SOC fractions and (2) to evaluate how aggregation (MWD) relates to SOC and cumulative C input, across 10 different cropping systems. Using SOM fractionation techniques, soil samples from 10 cropping systems at LTRAS (Long-term Research on Agricultural Systems, Davis, CA) were separated into four aggregate size classes (LM: >2000μ m, sM: 250-2000μ m, m: 53-250μ m, and silt&clay: <53μ m) and into three SOM fractions within LM and sM (cPOM:250-2000μ m, mM: 53-250μ m, and silt&clay: <53μ m). All fractions were analyzed for their C content. Empirically derived relationships between yield and aboveground biomass-C plus yield and belowground biomass-C were used to quantify C input from corn, wheat, and tomato residues as well as for legume cover crops and compost for the different cropping systems. We found a positive correlation between cumulative C input and SOC (R2=0.45, P<0.0001). After 9 years, MWD increased linearly with greater C input (R2=0.64, P<0.0001) and SOC (R2=0.61, P<0.0001), respectively. We observed that aggregate-C shifts from the microaggregate fraction (53-250μ m) in low C input systems to macroaggregate fractions (>2000

  9. Occurrence and fate of acrylamide in water-recycling systems and sludge in aggregate industries.

    PubMed

    Junqua, Guillaume; Spinelli, Sylvie; Gonzalez, Catherine

    2015-05-01

    Acrylamide is a hazardous substance having irritant and toxic properties as well as carcinogen, mutagen, and impaired fertility possible effects. Acrylamide might be found in the environment as a consequence of the use of polyacrylamides (PAMs) widely added as a flocculant for water treatment. Acrylamide is a monomer used to produce polyacrylamide (PAM) polymers. This reaction of polymerization can be incomplete, and acrylamide molecules can be present as traces in the commercial polymer. Thus, the use of PAMs may generate a release of acrylamide in the environment. In aggregate industries, PAM is widely involved in recycling process and water reuse (aggregate washing). Indeed, these industries consume large quantities of water. Thus, European and French regulations have favored loops of recycling of water in order to reduce water withdrawals. The main goal of this article is to study the occurrence and fate of acrylamide in water-recycling process as well as in the sludge produced by the flocculation treatment process in aggregate production plants. Moreover, to strengthen the relevance of this article, the objective is also to demonstrate if the recycling system leads to an accumulation effect in waters and sludge and if free acrylamide could be released by sludge during their storage. To reach this objective, water sampled at different steps of recycling water process has been analyzed as well as different sludge corresponding to various storage times. The obtained results reveal no accumulation effect in the water of the water-recycling system nor in the sludge.

  10. Modeling of Nonlinear Aggregation for Information Fusion Systems with Outliers Based on the Choquet Integral

    PubMed Central

    Su, Kuo-Lan; Jau, You-Min; Jeng, Jin-Tsong

    2011-01-01

    Modern information fusion systems essentially associate decision-making processes with multi-sensor systems. Precise decision-making processes depend upon aggregating useful information extracted from large numbers of messages or large datasets; meanwhile, the distributed multi-sensor systems which employ several geographically separated local sensors are required to provide sufficient messages or data with similar and/or dissimilar characteristics. These kinds of information fusion techniques have been widely investigated and used for implementing several information retrieval systems. However, the results obtained from the information fusion systems vary in different situations and performing intelligent aggregation and fusion of information from a distributed multi-source, multi-sensor network is essentially an optimization problem. A flexible and versatile framework which is able to solve complex global optimization problems is a valuable alternative to traditional information fusion. Furthermore, because of the highly dynamic and volatile nature of the information flow, a swift soft computing technique is imperative to satisfy the demands and challenges. In this paper, a nonlinear aggregation based on the Choquet integral (NACI) model is considered for information fusion systems that include outliers under inherent interaction among feature attributes. The estimation of interaction coefficients for the proposed model is also performed via a modified algorithm based on particle swarm optimization with quantum-behavior (QPSO) and the high breakdown value estimator, least trimmed squares (LTS). From simulation results, the proposed MQPSO algorithm with LTS (named LTS-MQPSO) readily corrects the deviations caused by outliers and swiftly achieves convergence in estimating the parameters of the proposed NACI model for the information fusion systems with outliers. PMID:22163747

  11. Mixed-host aggregations and helminth parasite sharing in an East African wildlife-livestock system.

    PubMed

    VanderWaal, Kimberly; Omondi, George Paul; Obanda, Vincent

    2014-09-15

    Parasitic infections transmitted between livestock and wildlife pose a significant risk to wildlife conservation efforts and constrain livestock productivity in tropical regions of the world. Gastrointestinal helminths are among the most ubiquitous parasites, and many parasites within this taxon can readily infect a wide range of host species. Factors shaping bidirectional transmission of parasites in wildlife-livestock systems are understudied. In this study, we investigate the prevalence and diversity of helminth infections in an East African community of wild and domestic ungulates. We also identify pairs of host species between which transmission may be possible based on shared parasite taxa, and explore the role of multi-host aggregations in shaping patterns of parasite sharing. Helminth taxa detected included Trichostrongylus, Trichuris, Paramphistomum, Skrjabinema, Strongyloides, Strongylus spp., and other strongyle-type nematodes. We found that nearly 50% of individuals harbored at least one species of helminth, but certain species, such as zebra and impala, exhibited higher prevalence than others. High canopy feeders, like giraffe, had lower prevalence than hosts feeding at medium and low foraging heights. For helminths, patterns of parasite sharing likely emerge from shared space use, which is mediated in part by mixed-species aggregations. The frequency with which host species associated together in mixed-species aggregations was positively correlated with the number of parasite taxa shared. We suggest that variation among species in their tendency to form mixed-species aggregations creates heterogeneity in transmission opportunities, and consequently, parasite sharing across ungulate species. These results enhance our understanding of the role of spatiotemporal relationships among host species in shaping parasite communities in mixed wildlife-livestock grazing systems. PMID:25086496

  12. HBV culture and infectious systems.

    PubMed

    Hayes, C Nelson; Chayama, Kazuaki

    2016-07-01

    While an effective vaccine against hepatitis B virus (HBV) has long been available, chronic HBV infection remains a severe global public health concern. Current treatment options have limited effectiveness, and long-term therapy is required to suppress HBV replication; however, complete elimination of the virus is rare. The lack of suitable animal models and infection systems has hindered efforts to unravel the HBV life cycle, particularly the early events in HBV entry, which appear to be highly species- and tissue-specific. Human primary hepatocytes remain the gold standard for HBV replication studies but are limited by availability and variability. While the HepaRG cell line is permissive for HBV replication, other hepatoma cell lines such as HepG2 do not support HBV replication. The recent discovery of sodium taurocholate transporting peptide (NTCP) as a primary receptor for HBV binding has led to the development of replication-competent cell lines such as HepG2-NTCP. Human hepatocytes grown in chimeric mice have provided another approach that allows primary human hepatocytes to be used while overcoming many of their limitations. Although the difficulty in developing HBV infection systems has hindered development of effective treatments, the variability and limited replication efficiency among cell lines point to additional liver-specific factors involved in HBV infection. It is hoped that HBV infection studies will lead to novel drug targets and therapeutic options for the treatment of chronic HBV infection.

  13. Modelling and laboratory studies on the adhesion fatigue performance for thin-film asphalt and aggregate system.

    PubMed

    Wang, Dongsheng; Yi, Junyan; Feng, Decheng

    2014-01-01

    Adhesion between asphalt and aggregate plays an important role in the performance of asphalt mixtures. A low-frequency adhesion fatigue test was proposed in this paper to study the effect of environment on the asphalt-aggregate adhesion system. The stress-based fatigue model had been utilized to describe the fatigue behavior of thin-film asphalt and aggregate system. The factors influencing the adhesion fatigue performance were also investigated. Experiment results show that asphalt has more important effect on the adhesion performance comparing with aggregate. Basalt, which is regarded as hydrophobic aggregates with low silica content, has better adhesion performance to asphalt binder when compared with granite. The effects of aging on the adhesion fatigue performance are different for PG64-22 and rubber asphalt. Long-term aging is found to reduce the adhesion fatigue lives for rubber asphalt and aggregate system, while the effect of long-term aging for aggregate and PG64-22 binder system is positive. Generally the increased stress amplitude and test temperature could induce greater damage and lead to less fatigue lives for adhesion test system. PMID:25054187

  14. Modelling and laboratory studies on the adhesion fatigue performance for thin-film asphalt and aggregate system.

    PubMed

    Wang, Dongsheng; Yi, Junyan; Feng, Decheng

    2014-01-01

    Adhesion between asphalt and aggregate plays an important role in the performance of asphalt mixtures. A low-frequency adhesion fatigue test was proposed in this paper to study the effect of environment on the asphalt-aggregate adhesion system. The stress-based fatigue model had been utilized to describe the fatigue behavior of thin-film asphalt and aggregate system. The factors influencing the adhesion fatigue performance were also investigated. Experiment results show that asphalt has more important effect on the adhesion performance comparing with aggregate. Basalt, which is regarded as hydrophobic aggregates with low silica content, has better adhesion performance to asphalt binder when compared with granite. The effects of aging on the adhesion fatigue performance are different for PG64-22 and rubber asphalt. Long-term aging is found to reduce the adhesion fatigue lives for rubber asphalt and aggregate system, while the effect of long-term aging for aggregate and PG64-22 binder system is positive. Generally the increased stress amplitude and test temperature could induce greater damage and lead to less fatigue lives for adhesion test system.

  15. Aggregation of magnetic microparticles in the context of targeted therapies actuated by a magnetic resonance imaging system

    NASA Astrophysics Data System (ADS)

    Mathieu, Jean-Baptiste; Martel, Sylvain

    2009-08-01

    A study of magnetic aggregation in the context of magnetic resonance imaging (MRI) based actuated targeting is proposed. MRI systems can induce displacement forces on magnetized particles as they flow through the blood vessels. Magnetic aggregation of the particles happens when they are placed within the magnetic field of the MRI system and can greatly influence the MRI steering dynamics of magnetic particles. In this paper, a review of the different parameters that can be used to tailor the size, geometry, stiffness, and density of magnetic aggregates is proposed. Then, magnetic aggregation experiments on a suspension of Fe3O4 microparticles ranging from 0.1 to 100 μm in diameter are described. The effects of particle concentration, flow rate, and magnetic field amplitude were evaluated. Field amplitudes of 1.5 mT, 0.4 T, and 1.5 T fields were applied without any magnetic steering gradients and caused aggregates that could sometimes exceed 1 mm in length. Since magnetic aggregates can reach higher magnetophoretic velocities than individual particles, large aggregates could be exploited in larger arteries with important blood flows. A few strategies are discussed to assist in the design of MRI steering experiments by enhancing the positive effects of magnetic aggregation over its negative effects.

  16. Factorial experimental design for the culture of human embryonic stem cells as aggregates in stirred suspension bioreactors reveals the potential for interaction effects between bioprocess parameters.

    PubMed

    Hunt, Megan M; Meng, Guoliang; Rancourt, Derrick E; Gates, Ian D; Kallos, Michael S

    2014-01-01

    Traditional optimization of culture parameters for the large-scale culture of human embryonic stem cells (ESCs) as aggregates is carried out in a stepwise manner whereby the effect of varying each culture parameter is investigated individually. However, as evidenced by the wide range of published protocols and culture performance indicators (growth rates, pluripotency marker expression, etc.), there is a lack of systematic investigation into the true effect of varying culture parameters especially with respect to potential interactions between culture variables. Here we describe the design and execution of a two-parameter, three-level (3(2)) factorial experiment resulting in nine conditions that were run in duplicate 125-mL stirred suspension bioreactors. The two parameters investigated here were inoculation density and agitation rate, which are easily controlled, but currently, poorly characterized. Cell readouts analyzed included fold expansion, maximum density, and exponential growth rate. Our results reveal that the choice of best case culture parameters was dependent on which cell property was chosen as the primary output variable. Subsequent statistical analyses via two-way analysis of variance indicated significant interaction effects between inoculation density and agitation rate specifically in the case of exponential growth rates. Results indicate that stepwise optimization has the potential to miss out on the true optimal case. In addition, choosing an optimum condition for a culture output of interest from the factorial design yielded similar results when repeated with the same cell line indicating reproducibility. We finally validated that human ESCs remain pluripotent in suspension culture as aggregates under our optimal conditions and maintain their differentiation capabilities as well as a stable karyotype and strong expression levels of specific human ESC markers over several passages in suspension bioreactors.

  17. A Dust Aggregation and Concentration System (DACS) for the Microgravity Space Environment

    NASA Technical Reports Server (NTRS)

    Giovane, F. J.; Blum, J.

    1999-01-01

    The Dust Aggregation and Concentration System, DACS, Project is an international effort intended to complete the preliminary definition of a system for suspending and concentrating dust particles in a microgravity environment for extended periods of time. The DACS design concept is based on extensive ground, drop tower, and parabolic flight tests. During the present proposed work, the DACS design will be completed, and a Science Requirements Document generated. At the end of the proposed 2 year project, DACS will be positioned to enter the advanced definition phase.

  18. Drosophila Melanogaster as a Model System for Studies of Islet Amyloid Polypeptide Aggregation

    PubMed Central

    Schultz, Sebastian Wolfgang; Nilsson, K. Peter R.; Westermark, Gunilla Torstensdotter

    2011-01-01

    Background Recent research supports that aggregation of islet amyloid polypeptide (IAPP) leads to cell death and this makes islet amyloid a plausible cause for the reduction of beta cell mass, demonstrated in patients with type 2 diabetes. IAPP is produced by the beta cells as a prohormone, and proIAPP is processed into IAPP by the prohormone convertases PC1/3 and PC2 in the secretory granules. Little is known about the pathogenesis for islet amyloid and which intracellular mechanisms are involved in amyloidogenesis and induction of cell death. Methodology/Principal Findings We have established expression of human proIAPP (hproIAPP), human IAPP (hIAPP) and the non-amyloidogenic mouse IAPP (mIAPP) in Drosophila melanogaster, and compared survival of flies with the expression driven to different cell populations. Only flies expressing hproIAPP in neurons driven by the Gal4 driver elavC155,Gal4 showed a reduction in lifespan whereas neither expression of hIAPP or mIAPP influenced survival. Both hIAPP and hproIAPP expression caused formation of aggregates in CNS and fat body region, and these aggregates were both stained by the dyes Congo red and pFTAA, both known to detect amyloid. Also, the morphology of the highly organized protein granules that developed in the fat body of the head in hIAPP and hproIAPP expressing flies was characterized, and determined to consist of 15.8 nm thick pentagonal rod-like structures. Conclusions/Significance These findings point to a potential for Drosophila melanogaster to serve as a model system for studies of hproIAPP and hIAPP expression with subsequent aggregation and developed pathology. PMID:21695120

  19. Development of a Scalable, High-Throughput-Compatible Assay to Detect Tau Aggregates Using iPSC-Derived Cortical Neurons Maintained in a Three-Dimensional Culture Format.

    PubMed

    Medda, X; Mertens, L; Versweyveld, S; Diels, A; Barnham, L; Bretteville, A; Buist, A; Verheyen, A; Royaux, I; Ebneth, A; Cabrera-Socorro, A

    2016-09-01

    Tau aggregation is the pathological hallmark that best correlates with the progression of Alzheimer's disease (AD). The presence of neurofibrillary tangles (NFTs), formed of hyperphosphorylated tau, leads to neuronal dysfunction and loss, and is directly associated with the cognitive decline observed in AD patients. The limited success in targeting β-amyloid pathologies has reinforced the hypothesis of blocking tau phosphorylation, aggregation, and/or spreading as alternative therapeutic entry points to treat AD. Identification of novel therapies requires disease-relevant and scalable assays capable of reproducing key features of the pathology in an in vitro setting. Here we use induced pluripotent stem cells (iPSCs) as a virtually unlimited source of human cortical neurons to develop a robust and scalable tau aggregation model compatible with high-throughput screening (HTS). We downscaled cell culture conditions to 384-well plate format and used Matrigel to introduce an extra physical protection against cell detachment that reduces shearing stress and better recapitulates pathological conditions. We complemented the assay with AlphaLISA technology for the detection of tau aggregates in a high-throughput-compatible format. The assay is reproducible across users and works with different commercially available iPSC lines, representing a highly translational tool for the identification of novel treatments against tauopathies, including AD. PMID:26984927

  20. Oil as reaction medium for glycation, oxidation, denaturation, and aggregation of whey protein systems of low water activity.

    PubMed

    Potes, Naritchaya; Kerry, Joseph P; Roos, Yrjö H

    2013-04-17

    Whey protein isolate (WPI)-oil (75:25) and WPI-oil-(glucose-fructose) (45:15:40) as models of high-protein systems containing either olive (OO) or sunflower oil (SO) were stored at 20 or 40 °C to investigate component interactions. The indicators of protein oxidation (carbonyl content) and aggregation (total sulfhydryl content) and heats of protein denaturation and aggregation were investigated. Highest levels of disulfide bonding and carbonyls in WPI-OO formed during the first 2 weeks of storage concomitantly with enhanced protein aggregation. WPI-OO and WPI-SO systems (prestorage) showed increased protein denaturation temperature. The WPI proteins showed higher heat sensitivity with OO or SO at 40 °C, and the system with OO showed preaggregated protein as found from decreased heats of protein aggregation. OO or SO in WPI-oil-(glucose-fructose) systems reduced heats of protein aggregation. Lipid oxidation products and nonenzymatic browning reactions in glucose-fructose-containing systems decreased the solubility of solids and increased protein aggregation, hydrophobicity, and hardening of structure. PMID:23517062

  1. McrEngine: A Scalable Checkpointing System Using Data-Aware Aggregation and Compression

    DOE PAGES

    Islam, Tanzima Zerin; Mohror, Kathryn; Bagchi, Saurabh; Moody, Adam; de Supinski, Bronis R.; Eigenmann, Rudolf

    2013-01-01

    High performance computing (HPC) systems use checkpoint-restart to tolerate failures. Typically, applications store their states in checkpoints on a parallel file system (PFS). As applications scale up, checkpoint-restart incurs high overheads due to contention for PFS resources. The high overheads force large-scale applications to reduce checkpoint frequency, which means more compute time is lost in the event of failure. We alleviate this problem through a scalable checkpoint-restart system, mcrEngine. McrEngine aggregates checkpoints from multiple application processes with knowledge of the data semantics available through widely-used I/O libraries, e.g., HDF5 and netCDF, and compresses them. Our novel scheme improves compressibility ofmore » checkpoints up to 115% over simple concatenation and compression. Our evaluation with large-scale application checkpoints show that mcrEngine reduces checkpointing overhead by up to 87% and restart overhead by up to 62% over a baseline with no aggregation or compression.« less

  2. Decentralized Random Decrement Technique for Data Aggregation and System Identification in Wireless Smart Sensor Networks

    NASA Astrophysics Data System (ADS)

    Sim, Sung-Han; Spencer, B. F.; Jo, Hongki; Carbonell-Márquez, Juan Francisco

    Smart sensors have been recognized as a promising technology with the potential to overcome many of the inherent difficulties and limitations associated with traditional wired structural health monitoring (SHM) systems. The unique features offered by smart sensors, including wireless communication, on-board computation, and cost effectiveness, enable deployment of the dense array of sensors that are needed for monitoring of large-scale civil infrastructure. Despite the many advances in smart sensor technologies, power consumption is still considered as one of the most important challenges that should be addressed for the smart sensors to be more widely adopted in SHM applications. Data communication, the most significant source of the power consumption, can be reduced by appropriately selecting data processing schemes and the related network topology. This paper presents a new decentralized data aggregation approach for system identification based on the Random Decrement Technique (RDT). Following a brief overview of RDT, which is an output-only system identification approach, a hierarchical approach is described and shown to be suitable for implementation in the intrinsically decentralized computing environment found in wireless smart sensor networks (WSSNs). RDT-based decentralized data aggregation is then implemented on the Imote2 smart sensor platform based on the Illinois Structural Health Monitoring Project (ISHMP) Services Toolsuite. Finally, the efficacy of the decentralized RDT method is demonstrated experimentally in terms of the required data communication and the accuracy of identified dynamic properties.

  3. Constructing compact and effective graphs for recommender systems via node and edge aggregations

    SciTech Connect

    Lee, Sangkeun; Kahng, Minsuk; Lee, Sang-goo

    2014-12-10

    Exploiting graphs for recommender systems has great potential to flexibly incorporate heterogeneous information for producing better recommendation results. As our baseline approach, we first introduce a naive graph-based recommendation method, which operates with a heterogeneous log-metadata graph constructed from user log and content metadata databases. Although the na ve graph-based recommendation method is simple, it allows us to take advantages of heterogeneous information and shows promising flexibility and recommendation accuracy. However, it often leads to extensive processing time due to the sheer size of the graphs constructed from entire user log and content metadata databases. In this paper, we propose node and edge aggregation approaches to constructing compact and e ective graphs called Factor-Item bipartite graphs by aggregating nodes and edges of a log-metadata graph. Furthermore, experimental results using real world datasets indicate that our approach can significantly reduce the size of graphs exploited for recommender systems without sacrificing the recommendation quality.

  4. Constructing compact and effective graphs for recommender systems via node and edge aggregations

    DOE PAGES

    Lee, Sangkeun; Kahng, Minsuk; Lee, Sang-goo

    2014-12-10

    Exploiting graphs for recommender systems has great potential to flexibly incorporate heterogeneous information for producing better recommendation results. As our baseline approach, we first introduce a naive graph-based recommendation method, which operates with a heterogeneous log-metadata graph constructed from user log and content metadata databases. Although the na ve graph-based recommendation method is simple, it allows us to take advantages of heterogeneous information and shows promising flexibility and recommendation accuracy. However, it often leads to extensive processing time due to the sheer size of the graphs constructed from entire user log and content metadata databases. In this paper, we proposemore » node and edge aggregation approaches to constructing compact and e ective graphs called Factor-Item bipartite graphs by aggregating nodes and edges of a log-metadata graph. Furthermore, experimental results using real world datasets indicate that our approach can significantly reduce the size of graphs exploited for recommender systems without sacrificing the recommendation quality.« less

  5. [Effect of Natural Organic Matter and Electrolytes on the Aggregation of C60 Nanoparticles in Aquatic Systems].

    PubMed

    Fang, Hua; Jing, Jie; Yu, Jiang-hua; Wang, Yu-ting

    2015-10-01

    The ettect of natural organic matter (NOM) and electrolytes on the aggregation of G60 nanoparticles in aquatic systems was studied by using dynamic light scattering. The results showed that the concentration of C60 stable suspension prepared by toluene solvent-exchange method was about 20 mg x L(-1). The C60 nanoparticles in the suspension showed a high zeta potential and particle diameter was around 120 nm. Addition of simple electrolytes induced aggregation of C60 nanoparticles through acompressing electric double layer, which was consistent with the classic Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloidal stability. The critical coagulation concentration (CCC) values of MgCl2 and CaCl2 were 9.6 and 6.7 mmol x L(-1). In presence of humic acid, the addition of NaCl and MgCl2 reduced the attachment efficiency and aggregation rate of C60 and increased CCCs. Humic acid enhanced the stability of C60 in water due to steric repulsion. However, the complexation reaction between Ca2+ and humic acid caused adsorption bridging with C60, which increased the aggregation rate and led to enhanced aggregation. This was identified as the primary mechanism of such enhanced aggregation behaviour. The aggregation and dispersion of C60 in water was influenced by the characteristics of organic matters, electrolyte species and other complex factors.

  6. 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.

  7. The use of glycylhistidyllysine in culture systems.

    PubMed

    Pickart, L

    1981-06-01

    Glycylhistidyllysine (GHL), a tripeptide isolated from plasma, has been shown to alter the growth rate of many cell types and organisms in culture systems. The tripeptide is optimally active at concentrations between 10 and 200 ng/ml. Some of the more interesting uses of GHL are highlighted in this paper. Present information suggests that GHL functions as a transporter of transition metals, in particular copper, to the cell surface for uptake into the cell. PMID:7021400

  8. Dynamic cell culture system (7-IML-1)

    NASA Technical Reports Server (NTRS)

    Cogoli, Augusto

    1992-01-01

    This experiment is one of the Biorack experiments being flown on the International Microgravity Laboratory 1 (MIL-1) mission as part of an investigation studying cell proliferation and performance in space. One of the objectives of this investigation is to assess the potential benefits of bioprocessing in space with the ultimate goal of developing a bioreactor for continuous cell cultures in space. This experiment will test the operation of an automated culture chamber that was designed for use in a Bioreactor in space. The device to be tested is called the Dynamic Cell Culture System (DCCS). It is a simple device in which media are renewed or chemicals are injected automatically, by means of osmotic pumps. This experiment uses four Type I/O experiment containers. One DCCS unit, which contains a culture chamber with renewal of medium and a second chamber without a medium supply fits in each container. Two DCCS units are maintained under zero gravity conditions during the on-orbit period. The other two units are maintained under 1 gh conditions in a 1 g centrifuge. The schedule for incubator transfer is given.

  9. Platelet aggregation monitoring with a newly developed quartz crystal microbalance system as an alternative to optical platelet aggregometry.

    PubMed

    Sinn, Stefan; Müller, Lothar; Drechsel, Hartmut; Wandel, Michael; Northoff, Hinnak; Ziemer, Gerhard; Wendel, Hans P; Gehring, Frank K

    2010-11-01

    The objective of this study was to establish a new test system for the monitoring of platelet aggregation during extracorporeal circulation (ECC) procedures. Even though extensive progress has been made in improving the haemocompatibility of extracorporeal circulation devices, activation of blood coagulation, blood platelets and inflammatory responses are still undesired outcomes of cardiopulmonary bypass. This study deals with an approach towards a platelet aggregation measuring system using a newly developed quartz crystal microbalance (QCM) system. Since QCM is a rarely used technique in the field of blood analytics, the challenge was to transfer the well established methods of aggregometry to the new test system. In a QCM system, either bare gold or fibrinogen-coated sensors were incubated with ADP or arachidonic acid (AA) stimulated platelet rich plasma. For negative controls the GPIIb/IIIa inhibitory antibody abciximab (Reopro®) was used as an inhibitor of platelet aggregation. During incubation, the frequency shifts of the sensors were recorded. The results gained from the QCM system were compared to results gained by optical platelet aggregometry (born aggregometry). For additional visualization of platelet adhesion to the sensor surfaces, fluorescent microscopy and scanning electron microscopy were used. The QCM sensor was able to detect platelet aggregation in both uncoated and fibrinogen coated sensors. The measuring curves of aggregation measurements and controls were clearly distinguishable from each other in terms of frequency shifts and kinetics. For aggregation measurements and inhibited controls the therapeutic diagnosis of platelet function is identical between aggregometer and QCM data. In future, QCM based measuring devices may become an alternative to established point of care methods for rapid bedside testing of platelet aggregation.

  10. Enhanced hepatic differentiation of rat bone marrow-derived mesenchymal stem cells in spheroidal aggregate culture on a decellularized liver scaffold

    PubMed Central

    Bao, Ji; Wu, Qiong; Wang, Yujia; Li, Yi; Li, Li; Chen, Fei; Wu, Xiujuan; Xie, Mingjun; Bu, Hong

    2016-01-01

    In the present study, we aimed to determine whether the combination of aggregate culture and decellularized liver scaffolds (DLSs) promoted the hepatic differentiation of murine bone marrow-derived mesenchymal stem cells (BM-MSCs) into high yields of mature hepatocytes in vitro. Four culturing methods for differentiation [single cell (2D), spheroids (3D), 2D + DLS and 3D + DLS] were studied. To determine the differentiation stages of the MSCs, RT-qPCR of the hepatocyte genes, immunostaining of hepatocyte markers, and functional analyses were all performed. Compared with the other groups, hepatocyte-like cells which differentiated from BM-MSC spheroids on extracellular matrix (ECM) exhibited more intensive staining of stored glycogen, an elevated level of urea biosynthesis and albumin secretion as well as the higher expression of hepatocyte-specific genes. Our results indicated that DLSs combined with spheroidal aggregate culture may be used as an effective method to facilitate the hepatic maturation of BM-MSCs and may have future applications in stem cell-based liver regenerative medicine. PMID:27314916

  11. M-BRIDGE: Wireless portable onbody aggregator and visualizer system for Wireless Body Sensor Network.

    PubMed

    Phyo Wai, Aung Aung; Ge, Yu

    2013-01-01

    Advances made in electronics, intelligent and wireless technologies enable individuals to self-observe their health states anywhere anytime. The shift in self care becomes a promising paradigm to alleviate burdens on centralized institutional care. As a result, Wireless Body Sensor Network (WBSN) personal health solutions can be seen increasingly although medical community still has concerns on their usability and applicability. Especially, there is still lacking in portable wireless wearable gateway to integrate WBSN into existing healthcare solutions. To fulfill this gap, we design and develop MobilE on-Body aGgregator and vIsualizer Device (M-BRIDGE) system using Android smart phone. Our proposed solution fully supports the needs of flexible device interfacing, data aggregation, efficient data distribution and user-friendly visualization. We also explain how M-BRIDGE's unique features and operation can complement with and fulfill the deficiency of existing WBSN healthcare solutions. We finally present the details of implementation and technical evaluation as well as discussion on the potential issues and future works. PMID:24109920

  12. Laboratory Drop Towers for the Experimental Simulation of Dust-aggregate Collisions in the Early Solar System

    PubMed Central

    Blum, Jürgen; Beitz, Eike; Bukhari, Mohtashim; Gundlach, Bastian; Hagemann, Jan-Hendrik; Heißelmann, Daniel; Kothe, Stefan; Schräpler, Rainer; von Borstel, Ingo; Weidling, René

    2014-01-01

    For the purpose of investigating the evolution of dust aggregates in the early Solar System, we developed two vacuum drop towers in which fragile dust aggregates with sizes up to ~10 cm and porosities up to 70% can be collided. One of the drop towers is primarily used for very low impact speeds down to below 0.01 m/sec and makes use of a double release mechanism. Collisions are recorded in stereo-view by two high-speed cameras, which fall along the glass vacuum tube in the center-of-mass frame of the two dust aggregates. The other free-fall tower makes use of an electromagnetic accelerator that is capable of gently accelerating dust aggregates to up to 5 m/sec. In combination with the release of another dust aggregate to free fall, collision speeds up to ~10 m/sec can be achieved. Here, two fixed high-speed cameras record the collision events. In both drop towers, the dust aggregates are in free fall during the collision so that they are weightless and match the conditions in the early Solar System. PMID:24962693

  13. Laboratory drop towers for the experimental simulation of dust-aggregate collisions in the early solar system.

    PubMed

    Blum, Jürgen; Beitz, Eike; Bukhari, Mohtashim; Gundlach, Bastian; Hagemann, Jan-Hendrik; Heißelmann, Daniel; Kothe, Stefan; Schräpler, Rainer; von Borstel, Ingo; Weidling, René

    2014-06-05

    For the purpose of investigating the evolution of dust aggregates in the early Solar System, we developed two vacuum drop towers in which fragile dust aggregates with sizes up to ~10 cm and porosities up to 70% can be collided. One of the drop towers is primarily used for very low impact speeds down to below 0.01 m/sec and makes use of a double release mechanism. Collisions are recorded in stereo-view by two high-speed cameras, which fall along the glass vacuum tube in the center-of-mass frame of the two dust aggregates. The other free-fall tower makes use of an electromagnetic accelerator that is capable of gently accelerating dust aggregates to up to 5 m/sec. In combination with the release of another dust aggregate to free fall, collision speeds up to ~10 m/sec can be achieved. Here, two fixed high-speed cameras record the collision events. In both drop towers, the dust aggregates are in free fall during the collision so that they are weightless and match the conditions in the early Solar System.

  14. Laboratory Drop Towers for the Experimental Simulation of Dust-aggregate Collisions in the Early Solar System

    NASA Astrophysics Data System (ADS)

    Blum, Jürgen; Beitz, Eike; Bukhari, Mohtashim; Gundlach, Bastian; Hagemann, Jan-Hendrik; Heißelmann, Daniel; Kothe, Stefan; Schräpler, Rainer; von Borstel, Ingo; Weidling, René

    2014-06-01

    For the purpose of investigating the evolution of dust aggregates in the early Solar System, we developed two vacuum drop towers in which fragile dust aggregates with sizes up to ~10 cm and porosities up to 70% can be collided. One of the drop towers is primarily used for very low impact speeds down to below 0.01 m/sec and makes use of a double release mechanism. Collisions are recorded in stereo-view by two high-speed cameras, which fall along the glass vacuum tube in the center-of-mass frame of the two dust aggregates. The other free-fall tower makes use of an electromagnetic accelerator that is capable of gently accelerating dust aggregates to up to 5 m/sec. In combination with the release of another dust aggregate to free fall, collision speeds up to ~10 m/sec can be achieved. Here, two fixed high-speed cameras record the collision events. In both drop towers, the dust aggregates are in free fall during the collision so that they are weightless and match the conditions in the early Solar System.

  15. Family systems theory, attachment theory, and culture.

    PubMed

    Rothbaum, Fred; Rosen, Karen; Ujiie, Tatsuo; Uchida, Nobuko

    2002-01-01

    Family systems theory and attachment theory have important similarities and complementarities. Here we consider two areas in which the theories converge: (a) in family system theorists' description of an overly close, or "enmeshed," mother-child dyad, which attachment theorists conceptualize as the interaction of children's ambivalent attachment and mothers' preoccupied attachment; (b) in family system theorists' description of the "pursuer-distance cycle" of marital conflict, which attachment theorists conceptualize as the interaction of preoccupied and dismissive partners. We briefly review family systems theory evidence, and more extensively review attachment theory evidence, pertaining to these points of convergence. We also review cross-cultural research, which leads us to conclude that the dynamics described in both theories reflect, in part, Western ways of thinking and Western patterns of relatedness. Evidence from Japan suggests that extremely close ties between mother and child are perceived as adaptive, and are more common, and that children experience less adverse effects from such relationships than do children in the West. Moreover, in Japan there is less emphasis on the importance of the exclusive spousal relationship, and less need for the mother and father to find time alone to rekindle romantic, intimate feelings and to resolve conflicts by openly communicating their differences. Thus, the "maladaptive" pattern frequently cited by Western theorists of an extremely close mother-child relationship, an unromantic, conflictual marriage characterized by little verbal communication and a peripheral, distant father, may function very differently in other cultures. While we believe that both theories will be greatly enriched by their integration, we caution against the application of either theory outside the cultures in which they were developed.

  16. Composition analysis of fractions of extracellular polymeric substances from an activated sludge culture and identification of dominant forces affecting microbial aggregation

    PubMed Central

    Guo, Xuan; Wang, Xu; Liu, Junxin

    2016-01-01

    Extracellular polymeric substances (EPS) appear to play a critical role in the formation of bioaggregates, such as sludge flocs, in activated sludge processes. Here, we systematically investigated the composition and chemical structure of various EPS fractions excreted from an activated sludge culture using multi-analysis techniques to examine the ability of the sludge to aggregate. Chemical analysis was used with a three-dimensional excitation emission matrix and Fourier transform infrared spectroscopy, applying inter-particle forces theory. The combined findings revealed that hydrophobic groups, especially protein-related N–H, were present in a greater proportion in tightly bound EPS (TB-EPS). This result, which explained the specificity of TB-EPS in the chemical structure, was consistent with data indicating that TB-EPS contained a large amount of protein-like substances (86.7 mg/g of mixed liquor volatile suspended solids, 39.7% of the total EPS). Subsequently, a novel experimental procedure was developed to pinpoint key inter-particle forces in sludge aggregation. The result revealed that hydrogen bonds are the predominant triggers that promote sludge aggregation. This comprehensive analysis indicated that hydrophobic proteins in TB-EPS are responsible for the critical role played by hydrogen bonds in sludge formation. Our findings highlight the need to elucidate the mechanisms of TB-EPS-mediated flocculation in future efforts. PMID:27311788

  17. Composition analysis of fractions of extracellular polymeric substances from an activated sludge culture and identification of dominant forces affecting microbial aggregation

    NASA Astrophysics Data System (ADS)

    Guo, Xuan; Wang, Xu; Liu, Junxin

    2016-06-01

    Extracellular polymeric substances (EPS) appear to play a critical role in the formation of bioaggregates, such as sludge flocs, in activated sludge processes. Here, we systematically investigated the composition and chemical structure of various EPS fractions excreted from an activated sludge culture using multi-analysis techniques to examine the ability of the sludge to aggregate. Chemical analysis was used with a three-dimensional excitation emission matrix and Fourier transform infrared spectroscopy, applying inter-particle forces theory. The combined findings revealed that hydrophobic groups, especially protein-related N–H, were present in a greater proportion in tightly bound EPS (TB-EPS). This result, which explained the specificity of TB-EPS in the chemical structure, was consistent with data indicating that TB-EPS contained a large amount of protein-like substances (86.7 mg/g of mixed liquor volatile suspended solids, 39.7% of the total EPS). Subsequently, a novel experimental procedure was developed to pinpoint key inter-particle forces in sludge aggregation. The result revealed that hydrogen bonds are the predominant triggers that promote sludge aggregation. This comprehensive analysis indicated that hydrophobic proteins in TB-EPS are responsible for the critical role played by hydrogen bonds in sludge formation. Our findings highlight the need to elucidate the mechanisms of TB-EPS-mediated flocculation in future efforts.

  18. In Situ Probing Nucleation, Growth, and Aggregation of Iron Oxides in Geochemical Aquatic Systems

    NASA Astrophysics Data System (ADS)

    Jun, Y.; Hu, Y.; Ray, J. R.

    2012-12-01

    Nucleation, growth, and aggregation of iron oxide nanoparticles can significantly alter the fate of organic and inorganic contaminants in geochemical aquatic systems. This talk will address how we can improve our understanding of nucleation, growth, and aggregation of iron oxide nanoparticles by providing more accurate quantitative and qualitative empirical information. In this study, a novel environmental setup—which allows time-resolved simultaneous measurements of small angle x-ray scattering (SAXS) and grazing incidence small-angle scattering (GISAXS) in the presence of bulk solution—was utilized for real-time monitoring of nanoparticle formation at water-mineral interfaces. This setup enabled us to probe the size, shape, and location of iron oxide nanoparticles on the substrate and in solution without dehydration of samples. Experiments were conducted with 10-4 M ferric ions in the presence of environmentally important and abundant anions (nitrate, chlorite, sulfate) and cations (aluminum) at pH = 3.7 ± 0.1. The substrates used were geologically ubiquitous media such as quartz, mica, and organic polymer-coated surfaces. Once ferric solutions were introduced, the homogeneous and heterogeneous nucleation of iron oxides occurred and the size and volume evolution of nanoparticles were monitored. To complement these observations, atomic force microscopy, high-resolution transmission electron microscopy, high-resolution x-ray diffraction, contact angle analysis, dynamic light scattering, and electrophoretic mobility analysis were utilized. Based on in situ measurements of initial nuclei evolution at aqueous interfaces, this approach provided new, important information for upscaling such as size, volume, surface area, and location (i.e., in solution vs. on mineral surfaces) of iron oxides precipitates formed in the presence of organic matter and different substrate morphological and chemical properties. Using this quantitative information, we identified the

  19. Neuroinflammation in Multiple System Atrophy: Response to and Cause of α-Synuclein Aggregation

    PubMed Central

    Vieira, Bruno Di Marco; Radford, Rowan A.; Chung, Roger S.; Guillemin, Gilles J.; Pountney, Dean L.

    2015-01-01

    Multiple system atrophy (MSA) is a progressive neurodegenerative disease presenting with combinations of autonomic dysfunction, parkinsonism, cerebellar ataxia and/or pyramidal signs. Oligodendroglial cytoplasmic inclusions (GCIs) rich in α-synuclein (α-syn) constitute the disease hallmark, accompanied by neuronal loss and activation of glial cells which indicate neuroinflammation. Recent studies demonstrate that α-syn may be released from degenerating neurons to mediate formation of abnormal inclusion bodies and to induce neuroinflammation which, interestingly, might also favor the formation of intracellular α-syn aggregates as a consequence of cytokine release and the shift to a pro-inflammatory environment. Here, we critically review the relationships between α-syn and astrocytic and microglial activation in MSA to explore the potential of therapeutics which target neuroinflammation. PMID:26778958

  20. A novel, smart microsphere with K(+)-induced shrinking and aggregating properties based on a responsive host-guest system.

    PubMed

    Jiang, Ming-Yue; Ju, Xiao-Jie; Fang, Lu; Liu, Zhuang; Yu, Hai-Rong; Jiang, Lu; Wang, Wei; Xie, Rui; Chen, Qianming; Chu, Liang-Yin

    2014-01-01

    A novel type of smart microspheres with K(+)-induced shrinking and aggregating properties is designed and developed on the basis of a K(+)-recognition host-guest system. The microspheres are composed of cross-linked poly(N-isopropylacrylamide-co-acryloylamidobenzo-15-crown-5) (P(NIPAM-co-AAB15C5)) networks. Due to the formation of stable 2:1 "sandwich-type" host-guest complexes between 15-crown-5 units and K(+) ions, the P(NIPAM-co-AAB15C5) microspheres significantly exhibit isothermally and synchronously K(+)-induced shrinking and aggregating properties at a low K(+) concentration, while other cations (e.g., Na(+), H(+), NH4(+), Mg(2+), or Ca(2+)) cannot trigger such response behaviors. Effects of chemical compositions of microspheres on the K(+)-induced shrinking and aggregating behaviors are investigated systematically. The K(+)-induced aggregating sensitivity of the P(NIPAM-co-AAB15C5) microspheres can be enhanced by increasing the content of crown ether units in the polymeric networks; however, it is nearly not influenced by varying the monomer and cross-linker concentrations in the microsphere preparation. State diagrams of the dispersed-to-aggregated transformation of P(NIPAM-co-AAB15C5) microspheres in aqueous solutions as a function of temperature and K(+) concentration are constructed, which provide valuable information for tuning the dispersed/aggregated states of microspheres by varying environmental K(+) concentration and temperature. The microspheres with synchronously K(+)-induced shrinking and aggregating properties proposed in this study provide a brand-new model for designing novel targeted drug delivery systems.

  1. A 3D Sphere Culture System Containing Functional Polymers for Large-Scale Human Pluripotent Stem Cell Production

    PubMed Central

    Otsuji, Tomomi G.; Bin, Jiang; Yoshimura, Azumi; Tomura, Misayo; Tateyama, Daiki; Minami, Itsunari; Yoshikawa, Yoshihiro; Aiba, Kazuhiro; Heuser, John E.; Nishino, Taito; Hasegawa, Kouichi; Nakatsuji, Norio

    2014-01-01

    Summary Utilizing human pluripotent stem cells (hPSCs) in cell-based therapy and drug discovery requires large-scale cell production. However, scaling up conventional adherent cultures presents challenges of maintaining a uniform high quality at low cost. In this regard, suspension cultures are a viable alternative, because they are scalable and do not require adhesion surfaces. 3D culture systems such as bioreactors can be exploited for large-scale production. However, the limitations of current suspension culture methods include spontaneous fusion between cell aggregates and suboptimal passaging methods by dissociation and reaggregation. 3D culture systems that dynamically stir carrier beads or cell aggregates should be refined to reduce shearing forces that damage hPSCs. Here, we report a simple 3D sphere culture system that incorporates mechanical passaging and functional polymers. This setup resolves major problems associated with suspension culture methods and dynamic stirring systems and may be optimal for applications involving large-scale hPSC production. PMID:24936458

  2. Where the wild things are: Predicting hotspots of seabird aggregations in the California Current System

    USGS Publications Warehouse

    Nur, N.; Jahncke, J.; Herzog, M.P.; Howar, J.; Hyrenbach, K.D.; Zamon, J.E.; Ainley, D.G.; Wiens, J.A.; Morgan, K.; Balance, L.T.; Stralberg, D.

    2011-01-01

    Marine Protected Areas (MPAs) provide an important tool for conservation of marine ecosystems. To be most effective, these areas should be strategically located in a manner that supports ecosystem function. To inform marine spatial planning and support strategic establishment of MPAs within the California Current System, we identified areas predicted to support multispecies aggregations of seabirds ("hotspot????). We developed habitat-association models for 16 species using information from at-sea observations collected over an 11-year period (1997-2008), bathymetric data, and remotely sensed oceanographic data for an area from north of Vancouver Island, Canada, to the USA/Mexico border and seaward 600 km from the coast. This approach enabled us to predict distribution and abundance of seabirds even in areas of few or no surveys. We developed single-species predictive models using a machine-learning algorithm: bagged decision trees. Single-species predictions were then combined to identify potential hotspots of seabird aggregation, using three criteria: (1) overall abundance among species, (2) importance of specific areas ("core area????) to individual species, and (3) predicted persistence of hotspots across years. Model predictions were applied to the entire California Current for four seasons (represented by February, May, July, and October) in each of 11 years. Overall, bathymetric variables were often important predictive variables, whereas oceanographic variables derived from remotely sensed data were generally less important. Predicted hotspots often aligned with currently protected areas (e.g., National Marine Sanctuaries), but we also identified potential hotspots in Northern California/Southern Oregon (from Cape Mendocino to Heceta Bank), Southern California (adjacent to the Channel Islands), and adjacent to Vancouver Island, British Columbia, that are not currently included in protected areas. Prioritization and identification of multispecies hotspots

  3. Texture development and slip systems in bridgmanite and bridgmanite + ferropericlase aggregates

    NASA Astrophysics Data System (ADS)

    Miyagi, L.; Wenk, H.-R.

    2016-09-01

    Bridgmanite (Mg,Fe)SiO3 and ferropericlase (Mg,Fe)O are the most abundant phases in the lower mantle and localized regions of the D″ layer just above the core mantle boundary. Seismic anisotropy is observed near subduction zones at the top of the lower mantle and in the D″ region. One source of anisotropy is dislocation glide and associated texture (crystallographic preferred orientation) development. Thus, in order to interpret seismic anisotropy, it is important to understand texture development and slip system activities in bridgmanite and bridgmanite + ferropericlase aggregates. Here we report on in situ texture development in bridgmanite and bridgmanite + ferropericlase aggregates deformed in the diamond anvil cell up to 61 GPa. When bridgmanite is synthesized from enstatite, it exhibits a strong (4.2 m.r.d.) 001 transformation texture due to a structural relationship with the precursor enstatite phase. When bridgmanite + ferropericlase are synthesized from olivine or ringwoodite, bridgmanite exhibits a relatively weak 100 transformation texture (1.2 and 1.6 m.r.d., respectively). This is likely due to minimization of elastic strain energy as a result of Young's modulus anisotropy. In bridgmanite, 001 deformation textures are observed at pressures <55 GPa. The 001 texture is likely due to slip on (001) planes in the [100], [010] and < {110} rangle directions. Stress relaxation by laser annealing to 1500-1600 K does not result in a change in this texture type. However, at pressures >55 GPa a change in texture to a 100 maximum is observed, consistent with slip on the (100) plane. Ferropericlase, when deformed with bridgmanite, does not develop a coherent texture. This is likely due to strain heterogeneity within the softer ferropericlase grains. Thus, it is plausible that ferropericlase is not a significant source of anisotropy in the lower mantle.

  4. The self-assembly, aggregation and phase transitions of food protein systems in one, two and three dimensions

    NASA Astrophysics Data System (ADS)

    Mezzenga, Raffaele; Fischer, Peter

    2013-04-01

    The aggregation of proteins is of fundamental relevance in a number of daily phenomena, as important and diverse as blood coagulation, medical diseases, or cooking an egg in the kitchen. Colloidal food systems, in particular, are examples that have great significance for protein aggregation, not only for their importance and implications, which touches on everyday life, but also because they allow the limits of the colloidal science analogy to be tested in a much broader window of conditions, such as pH, ionic strength, concentration and temperature. Thus, studying the aggregation and self-assembly of proteins in foods challenges our understanding of these complex systems from both the molecular and statistical physics perspectives. Last but not least, food offers a unique playground to study the aggregation of proteins in three, two and one dimensions, that is to say, in the bulk, at air/water and oil/water interfaces and in protein fibrillation phenomena. In this review we will tackle this very ambitious task in order to discuss the current understanding of protein aggregation in the framework of foods, which is possibly one of the broadest contexts, yet is of tremendous daily relevance.

  5. The substance of cultural evolution: culturally framed systems of social organization.

    PubMed

    Read, Dwight W

    2014-06-01

    Models of cultural evolution need to address not only the organizational aspects of human societies, but also the complexity and structure of cultural idea systems that frame their systems of organization. These cultural idea systems determine a framework within which behaviors take place and provide mutually understood meanings for behavior from the perspective of both agent and recipient that are critical for the coherence of human systems of social organization.

  6. Principles of the equilibrium theory of small multicomponent systems in three aggregate states

    NASA Astrophysics Data System (ADS)

    Tovbin, Yu. K.

    2015-11-01

    Principles of the molecular statistical theory of small multicomponent drops/microcrystals in a three-dimensional bulk and in two-dimensional adsorption systems are developed. Equations of the theory are derived using the cluster approach. The theory describes discrete distributions of molecules in space (on a size scale comparable to the molecular size) and continuous molecular distributions (at short distances inside cells) upon their translational and vibrational motions. The theory provides a unified description of the equilibrium molecular distributions in three aggregate states and at their interfaces. Pair intermolecular interaction potentials (such as the Mie potential) in several coordination spheres that determine lattice structure compressibility are taken into account. For simplicity, it is considered that the sizes of mixture components are virtually the same. Structural cell distribution functions for the transition region of curved interfaces are derived. Expressions for the pressure tensor components inside small bodies are obtained, allowing us to calculate the thermodynamic characteristics of a vapor-liquid interface, including surface tension. Questions regarding the consistency between the theory of phase transitions in small systems and the traditional theory of associate (cluster) formation and the transition to systems limited in the total volume value are discussed.

  7. Cell aggregation and sedimentation.

    PubMed

    Davis, R H

    1995-01-01

    The aggregation of cells into clumps or flocs has been exploited for decades in such applications as biological wastewater treatment, beer brewing, antibiotic fermentation, and enhanced sedimentation to aid in cell recovery or retention. More recent research has included the use of cell aggregation and sedimentation to selectively separate subpopulations of cells. Potential biotechnological applications include overcoming contamination, maintaining plasmid-bearing cells in continuous fermentors, and selectively removing nonviable hybridoma cells from perfusion cultures.

  8. EPR and luminescence data on the nitrogen aggregation in diamonds from Snap Lake dyke system

    NASA Astrophysics Data System (ADS)

    Nadolinny, Vladimir A.; Yurjeva, Olga P.; Pokhilenko, Nikolai P.

    2009-11-01

    More than 200 samples of diamonds from the Snap Lake dyke system in Canada were studied in details using optical and EPR spectroscopy. About 30% of them were colorless or slightly greenish tinted and were related to IaB type with a high aggregation level of defects: N3 (N 3V), B nitrogen centers (N 4V 0) and clusters of interstitials (B' centers). Traces of heavy plastic deformation in the crystals were found by X-ray techniques. Visual examination of photoluminescence (PL) of another batch of samples shows one type emission: a blue core surrounded by a green shell. As a rule these diamonds were colored in brownish to greenish tints and belong to the IaA type containing predominantly N-N nitrogen aggregates. Specific features of type IaB diamonds are a dominant broad line in the P2 EPR spectrum and an unusually high concentration of nitrogen in a single substitutional form, N S0. We suggest that this uncommon combination was produced naturally by the destruction of B-centers (N 4V 0) during plastic deformation. When IaA and IaB diamonds are heated, movement of dislocations throughout the crystal causes further decomposition of the complicated nitrogen defects (A, B), producing simpler nitrogen forms: P1, P2 and H3 centers. Analysis of light illumination effects on the IaB type diamonds revealed that some of these defects are in different charge states and the color of plastically deformed crystals is believed to be due to the charge transfer between the nitrogen defects and the dislocation core. Results of the current study suggest that a line broadening in P2/N3 and H3 systems and thus unusual ratio between strengths of the zero phonon lines and vibronic bands in PL spectra are related to the lattice distortion because of nearby dislocations. The sharp 1332 cm - 1 IR peak in these samples is due to N S+ rather than to B-centers. The PL 490.7 nm center, most manifesting itself in plastically deformed IaA diamonds, is first shown to be always accompanied by PL blue

  9. Micro 3D cell culture systems for cellular behavior studies: Culture matrices, devices, substrates, and in-situ sensing methods.

    PubMed

    Choi, Jonghoon; Lee, Eun Kyu; Choo, Jaebum; Yuh, Junhan; Hong, Jong Wook

    2015-09-01

    Microfabricated systems equipped with 3D cell culture devices and in-situ cellular biosensing tools can be a powerful bionanotechnology platform to investigate a variety of biomedical applications. Various construction substrates such as plastics, glass, and paper are used for microstructures. When selecting a construction substrate, a key consideration is a porous microenvironment that allows for spheroid growth and mimics the extracellular matrix (ECM) of cell aggregates. Various bio-functionalized hydrogels are ideal candidates that mimic the natural ECM for 3D cell culture. When selecting an optimal and appropriate microfabrication method, both the intended use of the system and the characteristics and restrictions of the target cells should be carefully considered. For highly sensitive and near-cell surface detection of excreted cellular compounds, SERS-based microsystems capable of dual modal imaging have the potential to be powerful tools; however, the development of optical reporters and nanoprobes remains a key challenge. We expect that the microsystems capable of both 3D cell culture and cellular response monitoring would serve as excellent tools to provide fundamental cellular behavior information for various biomedical applications such as metastasis, wound healing, high throughput screening, tissue engineering, regenerative medicine, and drug discovery and development. PMID:26358782

  10. Nanostructured diffusion-limited-aggregation crystal pattern formation in a reactive microemulsion system

    NASA Astrophysics Data System (ADS)

    Srivastava, Rohit; Srivastava, P. K.

    2014-03-01

    Nanostructured diffusion-limited-aggregation (DLA) crystal pattern formation in microemulsion consisting of water, styrene, cetyltrimethylammonium chloride (CTACl), potassium persulphate and an oscillating Belousov-Zhabotinsky (BZ) reactant is reported. A variety of spatiotemporal patterns like concentric wave, spatial (stripe) and chaotic patterns appear. A colloidal phase composed of numerous nano-sized particles has been observed. The solid phase nucleation has been found to occur in the colloidal phase and has been found to grow in a symmetric crystal pattern with the progress of the reaction finally exhibiting DLA structures. We show that the formation of a nanostructured DLA crystal pattern is governed by spatial structures emerging in the BZ microemulsion system. Without any spatial structure in the microemulsion system only hydrogel of high viscosity is formed. A nano-sized branched crystal pattern was formed with a particle diameter in the range of 60-100 nm, as evident by transmission electron microscope, powder x-ray diffraction and particle size analyser studies.

  11. Leveraging Human-environment Systems in Residential Buildings for Aggregate Energy Efficiency and Sustainability

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoqi

    Reducing the energy consumed in the built environment is a key objective in many sustainability initiatives. Existing energy saving methods have consisted of physical interventions to buildings and/or behavioral modifications of occupants. However, such methods may not only suffer from their own disadvantages, e.g. high cost and transient effect, but also lose aggregate energy saving potential due to the oftentimes-associated single-building-focused view and an isolated examination of occupant behaviors. This dissertation attempts to overcome the limitations of traditional energy saving research and practical approaches, and enhance residential building energy efficiency and sustainability by proposing innovative energy strategies from a holistic perspective of the aggregate human-environment systems. This holistic perspective features: (1) viewing buildings as mutual influences in the built environment, (2) leveraging both the individual and contextualized social aspects of occupant behaviors, and (3) incorporating interactions between the built environment and human behaviors. First, I integrate three interlinked components: buildings, residents, and the surrounding neighborhood, and quantify the potential energy savings to be gained from renovating buildings at the inter-building level and leveraging neighborhood-contextualized occupant social networks. Following the confirmation of both the inter-building effect among buildings and occupants' interpersonal influence on energy conservation, I extend the research further by examining the synergy that may exist at the intersection between these "engineered" building networks and "social" peer networks, focusing specifically on the additional energy saving potential that could result from interactions between the two components. Finally, I seek to reach an alignment of the human and building environment subsystems by matching the thermostat preferences of each household with the thermal conditions within their

  12. Investigating the feasibility of scale up and automation of human induced pluripotent stem cells cultured in aggregates in feeder free conditions.

    PubMed

    Soares, Filipa A C; Chandra, Amit; Thomas, Robert J; Pedersen, Roger A; Vallier, Ludovic; Williams, David J

    2014-03-10

    The transfer of a laboratory process into a manufacturing facility is one of the most critical steps required for the large scale production of cell-based therapy products. This study describes the first published protocol for scalable automated expansion of human induced pluripotent stem cell lines growing in aggregates in feeder-free and chemically defined medium. Cells were successfully transferred between different sites representative of research and manufacturing settings; and passaged manually and using the CompacT SelecT automation platform. Modified protocols were developed for the automated system and the management of cells aggregates (clumps) was identified as the critical step. Cellular morphology, pluripotency gene expression and differentiation into the three germ layers have been used compare the outcomes of manual and automated processes.

  13. A general ansatz for constructing quasi-diabatic states in electronically excited aggregated systems

    SciTech Connect

    Liu, Wenlan; Köhn, Andreas; Lunkenheimer, Bernd; Settels, Volker; Engels, Bernd; Fink, Reinhold F.

    2015-08-28

    We present a general method for analyzing the character of singly excited states in terms of charge transfer (CT) and locally excited (LE) configurations. The analysis is formulated for configuration interaction singles (CIS) singly excited wave functions of aggregate systems. It also approximately works for the second-order approximate coupled cluster singles and doubles and the second-order algebraic-diagrammatic construction methods [CC2 and ADC(2)]. The analysis method not only generates a weight of each character for an excited state, but also allows to define the related quasi-diabatic states and corresponding coupling matrix elements. In the character analysis approach, we divide the target system into domains and use a modified Pipek-Mezey algorithm to localize the canonical MOs on each domain, respectively. The CIS wavefunction is then transformed into the localized basis, which allows us to partition the wavefunction into LE configurations within domains and CT configuration between pairs of different domains. Quasi-diabatic states are then obtained by mixing excited states subject to the condition of maximizing the weight of one single LE or CT configuration (localization in configuration space). Different aims of such a procedure are discussed, either the construction of pure LE and CT states for analysis purposes (by including a large number of excited states) or the construction of effective models for dynamics calculations (by including a restricted number of excited states). Applications are given to LE/CT mixing in π-stacked systems, charge-recombination matrix elements in a hetero-dimer, and excitonic couplings in multi-chromophoric systems.

  14. Modes of Star Formation and Constraints on the Birth Aggregate of our Solar System

    NASA Astrophysics Data System (ADS)

    Adams, Fred C.

    This work suggests that star forming environments should be classified into finer divisions than the traditional isolated and clustered modes. Using the observed open cluster system, we estimate the fraction of star formation that takes place within cluster environments: Only about 10% of the stellar population originates from star forming regions destined to become open clusters. The smallest clusters included in the observational surveys (containing N˜100-300 members) roughly coincide with the smallest stellar systems that evolve as clusters in a dynamical sense. Specifically, we show that stellar systems with too few members N < N * have dynamical relaxation times that are shorter than their formation times (˜1-2 Myr), where the critical number of stars N * ≈ 100. Our results thus suggest that star formation can be characterized by (at least) three principal modes: [I] isolated singles and binaries, [II] groups (N < N *), and [III] clusters (N > N *). Many - if not most - stars form through the intermediate mode in stellar groups with 10 < N < N_* ˜ 100. The groups evolve and disperse much more rapidly than do open clusters and thus represent a different type of astronomical entity. Furthermore, groups and clusters affect star formation in different ways. Groups have a low probability of containing massive stars and are thus unaffected by supernovae and intense ultraviolet radiation fields. In addition, interactions between the young stellar objects are relatively rare in groups because of their short lifetimes and small stellar membership. Finally, we can apply these considerations to the formation of our own solar system and thereby find tight constraints on the solar birth aggregate.

  15. A general ansatz for constructing quasi-diabatic states in electronically excited aggregated systems.

    PubMed

    Liu, Wenlan; Lunkenheimer, Bernd; Settels, Volker; Engels, Bernd; Fink, Reinhold F; Köhn, Andreas

    2015-08-28

    We present a general method for analyzing the character of singly excited states in terms of charge transfer (CT) and locally excited (LE) configurations. The analysis is formulated for configuration interaction singles (CIS) singly excited wave functions of aggregate systems. It also approximately works for the second-order approximate coupled cluster singles and doubles and the second-order algebraic-diagrammatic construction methods [CC2 and ADC(2)]. The analysis method not only generates a weight of each character for an excited state, but also allows to define the related quasi-diabatic states and corresponding coupling matrix elements. In the character analysis approach, we divide the target system into domains and use a modified Pipek-Mezey algorithm to localize the canonical MOs on each domain, respectively. The CIS wavefunction is then transformed into the localized basis, which allows us to partition the wavefunction into LE configurations within domains and CT configuration between pairs of different domains. Quasi-diabatic states are then obtained by mixing excited states subject to the condition of maximizing the weight of one single LE or CT configuration (localization in configuration space). Different aims of such a procedure are discussed, either the construction of pure LE and CT states for analysis purposes (by including a large number of excited states) or the construction of effective models for dynamics calculations (by including a restricted number of excited states). Applications are given to LE/CT mixing in π-stacked systems, charge-recombination matrix elements in a hetero-dimer, and excitonic couplings in multi-chromophoric systems.

  16. Testing a theory of organizational culture, climate and youth outcomes in child welfare systems: a United States national study.

    PubMed

    Williams, Nathaniel J; Glisson, Charles

    2014-04-01

    Theories of organizational culture and climate (OCC) applied to child welfare systems hypothesize that strategic dimensions of organizational culture influence organizational climate and that OCC explains system variance in youth outcomes. This study provides the first structural test of the direct and indirect effects of culture and climate on youth outcomes in a national sample of child welfare systems and isolates specific culture and climate dimensions most associated with youth outcomes. The study applies multilevel path analysis (ML-PA) to a U.S. nationwide sample of 2,380 youth in 73 child welfare systems participating in the second National Survey of Child and Adolescent Well-being. Youths were selected in a national, two-stage, stratified random sample design. Youths' psychosocial functioning was assessed by caregivers' responses to the Child Behavior Checklist at intake and at 18-month follow-up. OCC was assessed by front-line caseworkers' (N=1,740) aggregated responses to the Organizational Social Context measure. Comparison of the a priori and subsequent trimmed models confirmed a reduced model that excluded rigid organizational culture and explained 70% of the system variance in youth outcomes. Controlling for youth- and system-level covariates, systems with more proficient and less resistant organizational cultures exhibited more functional, more engaged, and less stressful climates. Systems with more proficient cultures and more engaged, more functional, and more stressful climates exhibited superior youth outcomes. Findings suggest child welfare administrators can support service effectiveness with interventions that improve specific dimensions of culture and climate.

  17. LPS ligand and culture additives improve production of monomeric MD-1 and 2 in Pichia pastoris by decreasing aggregation and intermolecular disulfide bonding.

    PubMed

    Mengwasser, Kristen E; Bryant, Clare E; Gay, Nick J; Gangloff, Monique

    2011-04-01

    Myeloid differentiation proteins MD-1 and MD-2 have both been shown to form a heterogeneous collection of oligomers when expressed in absence of their respective receptor, RP105 and TLR4. The biological relevance of these oligomers is not clear. Only monomeric proteins have been found to be active and able to trigger an immune response to endotoxin by modulating the TLR4 pathway. In this study, we produced variants of MD-1 and MD-2 in Pichia pastoris. To minimize the time and expense of initial expression tests, small-scale cultures have been set up to allow the rapid identification of the highest expressing clone and the optimal expression conditions. The expression vectors used, the site of linearization and the locus of integration affected the yield of transformation. Next we screened culture additives and found that they significantly increased the fraction of monomeric proteins secreted in the culture medium (up to 15% of the total MD protein produced). We confirmed their presence by size-exclusion chromatography. Optimal anti-aggregation agents were protein-dependent except for LPS that presented stabilizing effects for all MD proteins. Contrary to previous reports, this study suggests that MD-1 can bind to LPS. PMID:21130168

  18. Effective Rho-associated protein kinase inhibitor treatment to dissociate human iPS cells for suspension culture to form embryoid body-like cell aggregates.

    PubMed

    Horiguchi, Ayumi; Yazaki, Koyuki; Aoyagi, Mami; Ohnuki, Yoshitsugu; Kurosawa, Hiroshi

    2014-11-01

    Treatment conditions using Y-27632 in the preparation of cell suspension of dissociated human pluripotent stem cells (hiPSCs) were investigated in the context of embryoid body (EB)-like cell aggregates. The effectiveness of a pretreatment with Y-27632 before cell dissociation and that of a Y-27632 treatment during cell dissociation were investigated from the viewpoint of simplicity and robustness. The duration of Y-27632 treatment in the preparation process affected the circularity and agglomeration of dissociated hiPSCs. A single application of pretreatment failed to prevent the onset of blebbing. However, a pretreatment promoted the agglomeration of dissociated hiPSCs when combined with the addition of Y-27632 to cell suspension. Our results indicate that pretreatment enhances the agglomeration potential of dissociated hiPSCs. When cell dissociation was performed in the presence of Y-27632, dissociated hiPSCs possessed the highest circularity and significant agglomerating property. It was shown that treatment with Y-27632 during cell dissociation is a simple and robust method to prepare dissociated hiPSCs for suspension culture to form EB-like cell aggregates.

  19. Aggregation kinetics of multiwalled carbon nanotubes in aquatic systems: measurements and environmental implications.

    PubMed

    Saleh, Navid B; Pfefferle, Lisa D; Elimelech, Menachem

    2008-11-01

    The initial aggregation kinetics of multiwalled carbon nanotubes (MWNTs) were examined through time-resolved dynamic light scattering. Aggregation of MWNTs was evaluated by varying solution pH and the concentration of monovalent (NaCl) and divalent (CaCl2 and MgCl2) salts. Suwannee River humic acid (SRHA) was used to study the effect of background natural organic matter on MWNT aggregation kinetics, Increasing salt concentration and addition of divalent calcium and magnesium ions induced MWNT aggregation by suppressing electrostatic repulsion, similar to observations with aquatic colloidal particles. The critical coagulation concentration (CCC) values for MWNTs were estimated as 25 mM NaCI, 2.6 mM CaCl2, and 1.5 mM MgCl2. An increase in solution pH from acidic (pH 3) to basic (pH 11) conditions resulted in a substantial (over 2 orders of magnitude) decrease in MWNT aggregation kinetics, suggesting the presence of ionizable functional groups on the MWNT carbon scaffold. The presence of humic acid in solution markedly enhanced the colloidal stability of MWNTs, reducing the aggregation rate by nearly 2 orders of magnitude. The enhanced MWNT stability in the presence of humic acid is attributable to steric repulsion imparted by adsorbed humic acid macromolecules. Our results suggest that MWNTs are relatively stable at solution pH and electrolyte conditions typical of aquatic environments.

  20. Heat capacity anomaly in a self-aggregating system: Triblock copolymer 17R4 in water

    NASA Astrophysics Data System (ADS)

    Dumancas, Lorenzo V.; Simpson, David E.; Jacobs, D. T.

    2015-05-01

    The reverse Pluronic, triblock copolymer 17R4 is formed from poly(propylene oxide) (PPO) and poly(ethylene oxide) (PEO): PPO14 - PEO24 - PPO14, where the number of monomers in each block is denoted by the subscripts. In water, 17R4 has a micellization line marking the transition from a unimer network to self-aggregated spherical micelles which is quite near a cloud point curve above which the system separates into copolymer-rich and copolymer-poor liquid phases. The phase separation has an Ising-like, lower consolute critical point with a well-determined critical temperature and composition. We have measured the heat capacity as a function of temperature using an adiabatic calorimeter for three compositions: (1) the critical composition where the anomaly at the critical point is analyzed, (2) a composition much less than the critical composition with a much smaller spike when the cloud point curve is crossed, and (3) a composition near where the micellization line intersects the cloud point curve that only shows micellization. For the critical composition, the heat capacity anomaly very near the critical point is observed for the first time in a Pluronic/water system and is described well as a second-order phase transition resulting from the copolymer-water interaction. For all compositions, the onset of micellization is clear, but the formation of micelles occurs over a broad range of temperatures and never becomes complete because micelles form differently in each phase above the cloud point curve. The integrated heat capacity gives an enthalpy that is smaller than the standard state enthalpy of micellization given by a van't Hoff plot, a typical result for Pluronic systems.

  1. Aggregating data for computational toxicology applications: The U.S. Environmental Protection Agency (EPA) Aggregated Computational Toxicology Resource (ACToR) System.

    PubMed

    Judson, Richard S; Martin, Matthew T; Egeghy, Peter; Gangwal, Sumit; Reif, David M; Kothiya, Parth; Wolf, Maritja; Cathey, Tommy; Transue, Thomas; Smith, Doris; Vail, James; Frame, Alicia; Mosher, Shad; Cohen Hubal, Elaine A; Richard, Ann M

    2012-01-01

    Computational toxicology combines data from high-throughput test methods, chemical structure analyses and other biological domains (e.g., genes, proteins, cells, tissues) with the goals of predicting and understanding the underlying mechanistic causes of chemical toxicity and for predicting toxicity of new chemicals and products. A key feature of such approaches is their reliance on knowledge extracted from large collections of data and data sets in computable formats. The U.S. Environmental Protection Agency (EPA) has developed a large data resource called ACToR (Aggregated Computational Toxicology Resource) to support these data-intensive efforts. ACToR comprises four main repositories: core ACToR (chemical identifiers and structures, and summary data on hazard, exposure, use, and other domains), ToxRefDB (Toxicity Reference Database, a compilation of detailed in vivo toxicity data from guideline studies), ExpoCastDB (detailed human exposure data from observational studies of selected chemicals), and ToxCastDB (data from high-throughput screening programs, including links to underlying biological information related to genes and pathways). The EPA DSSTox (Distributed Structure-Searchable Toxicity) program provides expert-reviewed chemical structures and associated information for these and other high-interest public inventories. Overall, the ACToR system contains information on about 400,000 chemicals from 1100 different sources. The entire system is built using open source tools and is freely available to download. This review describes the organization of the data repository and provides selected examples of use cases.

  2. Simple suspension culture system of human iPS cells maintaining their pluripotency for cardiac cell sheet engineering.

    PubMed

    Haraguchi, Yuji; Matsuura, Katsuhisa; Shimizu, Tatsuya; Yamato, Masayuki; Okano, Teruo

    2015-12-01

    In this study, a simple three-dimensional (3D) suspension culture method for the expansion and cardiac differentiation of human induced pluripotent stem cells (hiPSCs) is reported. The culture methods were easily adapted from two-dimensional (2D) to 3D culture without any additional manipulations. When hiPSCs were directly applied to 3D culture from 2D in a single-cell suspension, only a few aggregated cells were observed. However, after 3 days, culture of the small hiPSC aggregates in a spinner flask at the optimal agitation rate created aggregates which were capable of cell passages from the single-cell suspension. Cell numbers increased to approximately 10-fold after 12 days of culture. The undifferentiated state of expanded hiPSCs was confirmed by flow cytometry, immunocytochemistry and quantitative RT-PCR, and the hiPSCs differentiated into three germ layers. When the hiPSCs were subsequently cultured in a flask using cardiac differentiation medium, expression of cardiac cell-specific genes and beating cardiomyocytes were observed. Furthermore, the culture of hiPSCs on Matrigel-coated dishes with serum-free medium containing activin A, BMP4 and FGF-2 enabled it to generate robust spontaneous beating cardiomyocytes and these cells expressed several cardiac cell-related genes, including HCN4, MLC-2a and MLC-2v. This suggests that the expanded hiPSCs might maintain the potential to differentiate into several types of cardiomyocytes, including pacemakers. Moreover, when cardiac cell sheets were fabricated using differentiated cardiomyocytes, they beat spontaneously and synchronously, indicating electrically communicative tissue. This simple culture system might enable the generation of sufficient amounts of beating cardiomyocytes for use in cardiac regenerative medicine and tissue engineering.

  3. Two-dimensional gel electrophoresis for controlling and comparing culture supernatants of mammalian cell culture productions systems.

    PubMed

    Wimmer, K; Harant, H; Reiter, M; Blüml, G; Gaida, T; Katinger, H

    1994-01-01

    A recombinant Chinese hamster ovary cell line, producing human erythropoietin, was cultivated in a continuous mode in a stirred tank reactor applying different dilution rates. In order to monitor the stability of this expression system, product and non-product proteins of the cell culture supernatant were analyzed by two-dimensional electrophoresis. The consistency of the isoforms of the recombinant product was determined by western blot combined with specific staining. The same cell line was propagated in a high cell density cultivation system based on macro-cell-aggregates. The patterns of secreted proteins of the cell line cultivated in the different systems were compared in order to detect modifications in protein expression of the product and of non product proteins relevant for cell culture supernatant. Hardly any alterations in two-dimensional pattern were detectable. The isoforms of erythropoietin, as well as the overall pattern of secreted proteins, detectable with the two-dimensional electrophoresis method were remarkably stable under different cultivation conditions.

  4. Cultural systems for growing potatoes in space

    NASA Technical Reports Server (NTRS)

    Tibbitts, T.; Bula, R.; Corey, R.; Morrow, R.

    1988-01-01

    Higher plants are being evaluated for life support to provide needed food, oxygen and water as well as removal of carbon dioxide from the atmosphere. The successful utilization of plants in space will require the development of not only highly productive growing systems but also highly efficient bioregenerative systems. It will be necessary to recycle all inedible plant parts and all human wastes so that the entire complement of elemental compounds can be reused. Potatoes have been proposed as one of the desirable crops because they are 1) extremely productive, yielding more than 100 metric tons per hectare from field plantings, 2) the edible tubers are high in digestible starch (70%) and protein (10%) on a dry weight basis, 3) up to 80% of the total plant production is in tubers and thus edible, 4) the plants are easily propagated either from tubers or from tissue culture plantlets, 5) the tubers can be utilized with a minimum of processing, and 6) potatoes can be prepared in a variety of different forms for the human diet (Tibbitts et al., 1982). However potatoes have a growth pattern that complicates the development of growing the plants in controlled systems. Tubers are borne on underground stems that are botanically termed 'rhizomes', but in common usage termed 'stolons'. The stolons must be maintained in a dark, moist area with sufficient provision for enlargement of tubers. Stems rapidly terminate in flowers forcing extensive branching and spreading of plants so that individual plants will cover 0.2 m2 or more area. Thus the growing system must be developed to provide an area that is darkened for tuber and root growth and of sufficient size for plant spread. A system developed for growing potatoes, or any plants, in space will have certain requirements that must be met to make them a useful part of a life support system. The system must 1) be constructed of materials, and involve media, that can be reused for many successive cycles of plant growth, 2

  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. Microarray analysis of cultured human brain aggregates following cortisol exposure: implications for cellular functions relevant to mood disorders.

    PubMed

    Salaria, S; Chana, G; Caldara, F; Feltrin, E; Altieri, M; Faggioni, F; Domenici, E; Merlo-Pich, E; Everall, I P

    2006-09-01

    Increased cortisol levels in humans are often observed in patients suffering from mood disorders. In this study human fetal brain aggregates were exposed to cortisol at 500 nM for 3 weeks, as an in-vitro model of chronic cortisol exposure. Microarray analysis on extracted mRNA using the Affymetrix U133A platform was then performed. Our results demonstrated a significant effect of cortisol on 1648 transcripts; 736 up-regulated and 912 down-regulated genes. The most differentially regulated biological categories were: RNA processing, protein metabolism, and cell growth. Within these categories we observed a down-regulation of fibroblast growth factor 2 (FGF2) (-1.5-fold) and aquaporin4 (AQP4) (-1.7-fold), alongside an up-regulation of fibroblast growth factor 9 (FGF9) (+1.7-fold) and vesicle associated membrane protein2 (VAMP2) (+1.7-fold). FGF2, FGF9, AQP4 and VAMP2 changes were confirmed at the protein level by immunohistochemistry. Alterations in FGF transcripts are in keeping with recent literature demonstrating such effects in patients with mood disorders. PMID:16844382

  7. A 3D human neural cell culture system for modeling Alzheimer’s disease

    PubMed Central

    Kim, Young Hye; Choi, Se Hoon; D’Avanzo, Carla; Hebisch, Matthias; Sliwinski, Christopher; Bylykbashi, Enjana; Washicosky, Kevin J.; Klee, Justin B.; Brüstle, Oliver; Tanzi, Rudolph E.; Kim, Doo Yeon

    2015-01-01

    Stem cell technologies have facilitated the development of human cellular disease models that can be used to study pathogenesis and test therapeutic candidates. These models hold promise for complex neurological diseases such as Alzheimer’s disease (AD) because existing animal models have been unable to fully recapitulate all aspects of pathology. We recently reported the characterization of a novel three-dimensional (3D) culture system that exhibits key events in AD pathogenesis, including extracellular aggregation of β-amyloid and accumulation of hyperphosphorylated tau. Here we provide instructions for the generation and analysis of 3D human neural cell cultures, including the production of genetically modified human neural progenitor cells (hNPCs) with familial AD mutations, the differentiation of the hNPCs in a 3D matrix, and the analysis of AD pathogenesis. The 3D culture generation takes 1–2 days. The aggregation of β-amyloid is observed after 6-weeks of differentiation followed by robust tau pathology after 10–14 weeks. PMID:26068894

  8. Strong plasmon-exciton coupling in a hybrid system of gold nanostars and J-aggregates

    PubMed Central

    2013-01-01

    Hybrid materials formed by plasmonic nanostructures and J-aggregates provide a unique combination of highly localized and enhanced electromagnetic field in metal constituent with large oscillator strength and extremely narrow exciton band of the organic component. The coherent coupling of localized plasmons of the multispiked gold nanoparticles (nanostars) and excitons of JC1 dye J-aggregates results in a Rabi splitting reaching 260 meV. Importantly, broad absorption features of nanostars extending over a visible and near-infrared spectral range allowed us to demonstrate double Rabi splitting resulting from the simultaneous coherent coupling between plasmons of the nanostars and excitons of J-aggregates of two different cyanine dyes. PMID:23522305

  9. Functional Systems and Culturally-Determined Cognitive Differences.

    ERIC Educational Resources Information Center

    Wiseman, Richard L.

    Noting that one means of better understanding the nature of cultural differences is to elucidate the cognitive differences between members of differing cultures, this paper examines Alexander Luria's sociohistorical theory of functional cognitive systems. The paper first describes Luria's notion of functional systems, the crux of which postulates…

  10. Uncovering methods for the prevention of protein aggregation and improvement of product quality in a transient expression system.

    PubMed

    Estes, Bram; Hsu, Yueh-Rong; Tam, Lei-Ting; Sheng, Jackie; Stevens, Jennitte; Haldankar, Raj

    2015-01-01

    Mammalian expression systems are used routinely for the production of recombinant proteins as therapeutic molecules as well as research tools. Transient expression has become increasingly popular in recent years due to its rapid timeline and improvements in expression level. While improvements to transient expression systems have focused mainly on the level of protein expression, the aspect of protein quality has received little attention. The removal of undesirable products, such as aggregation, depends primarily on purification, requiring additional cumbersome steps, which can lead to a lower product yield and longer timelines. In this study, we show that reducing the level of transcription by transfecting at a lower gene dose improves the quality of secreted molecules prone to aggregation. For gene dosing to have this effect, it is critical for the carrier DNA to be an empty vector containing the same elements as the gene containing plasmid. This approach can be used in combination with a temperature shift to hypothermic conditions during production to enhance the effect. The observed improvements not only minimized aggregation levels, but also generated products with overall superior quality, including more homogeneous signal peptide cleavage and N-linked glycosylation profiles. These techniques have produced a similar improvement in product quality with a variety of other molecules, suggesting that this may be a general approach to enhance product quality from transient expression systems. PMID:25395220

  11. The famous versus the inconvenient - or the dawn and the rise of 3D-culture systems

    PubMed Central

    Altmann, Brigitte; Welle, Alexander; Giselbrecht, Stefan; Truckenmüller, Roman; Gottwald, Eric

    2009-01-01

    One of the greatest impacts on in vitro cell biology was the introduction of three-dimensional (3D) culture systems more than six decades ago and this era may be called the dawn of 3D-tissue culture. Although the advantages were obvious, this field of research was a “sleeping beauty” until the 1970s when multicellular spheroids were discovered as ideal tumor models. With this rebirth, organotypical culture systems became valuable tools and this trend continues to increase. While in the beginning, simple approaches, such as aggregation culture techniques, were favored due to their simplicity and convenience, now more sophisticated systems are used and are still being developed. One of the boosts in the development of new culture techniques arises from elaborate manufacturing and surface modification techniques, especially micro and nano system technologies that have either improved dramatically or have evolved very recently. With the help of these tools, it will soon be possible to generate even more sophisticated and more organotypic-like culture systems. Since 3D perfused or superfused systems are much more complex to set up and maintain compared to use of petri dishes and culture flasks, the added value of 3D approaches still needs to be demonstrated. PMID:21607106

  12. Soil 13C Dynamics in Aggregates Across a Soil Profile Under an Established Miscanthus System

    NASA Astrophysics Data System (ADS)

    Dondini, M.; Groenigen, K. J.; Jones, M.

    2008-12-01

    Soils are the largest pool of terrestrial organic carbon (C), containing nearly three times the amount of C as the atmosphere. Environmental changes that affect soil C dynamics could slow down the rise in atmospheric CO2 and associated warming by promoting soil C storage. Our capacity to predict the consequences for global change therefore depends on a better understanding of the distribution and controls of soil organic C and how vegetation change may affect SOC distributions. One land cover change of particular interest involves the establishment of bio energy crop stands. The full mitigation potential of bio energy crops cannot be considered without taking into account their effect on soil C dynamics. Miscanthus, a perennial C4 grass from Eastern Asia, has recently received considerable interest as a bio-energy crop. For that reason, we analyzed the C content and the 13C signatures across the soil profile in a 14 year old Miscanthus system, established on former arable land. We combined SOM fractionation techniques by size and density, allowing us to investigate small shifts in soil C stores that would be significant in the long term, but that might not be detected by conventional methodologies. The 13C signal of the various SOM fractions allowed us to distinguish between Miscanthus-derived vs. native soil organic C. Soils under Miscanthus contained 796 g C/m2 in the 0-15 cm layer, and 1233g C/m2 in the 15- 30 cm layer. These values are significantly higher than soil C contents in the arable land. Macroaggregates under Miscanthus contain more than twice as much C compared to arable land, showing a decrease in soil C content with decreasing aggregate size. These differences are largely caused by soil C storage in the microaggregate within macroaggregates fraction. Under Miscanthus, this fraction contains 440 g C/m2 and 488 g C/m2 at 0-15 cm and 15-30 cm respectively, while under the arable land it has mean values of 174 g C/m2 and 353 g C/m2. Our data suggest a

  13. Large-scale analysis of macromolecular crowding effects on protein aggregation using a reconstituted cell-free translation system

    PubMed Central

    Niwa, Tatsuya; Sugimoto, Ryota; Watanabe, Lisa; Nakamura, Shugo; Ueda, Takuya; Taguchi, Hideki

    2015-01-01

    Proteins must fold into their native structures in the crowded cellular environment, to perform their functions. Although such macromolecular crowding has been considered to affect the folding properties of proteins, large-scale experimental data have so far been lacking. Here, we individually translated 142 Escherichia coli cytoplasmic proteins using a reconstituted cell-free translation system in the presence of macromolecular crowding reagents (MCRs), Ficoll 70 or dextran 70, and evaluated the aggregation propensities of 142 proteins. The results showed that the MCR effects varied depending on the proteins, although the degree of these effects was modest. Statistical analyses suggested that structural parameters were involved in the effects of the MCRs. Our dataset provides a valuable resource to understand protein folding and aggregation inside cells. PMID:26500644

  14. Fibronectin Aggregation and Assembly

    PubMed Central

    Ohashi, Tomoo; Erickson, Harold P.

    2011-01-01

    The mechanism of fibronectin (FN) assembly and the self-association sites are still unclear and contradictory, although the N-terminal 70-kDa region (I1–9) is commonly accepted as one of the assembly sites. We previously found that I1–9 binds to superfibronectin, which is an artificial FN aggregate induced by anastellin. In the present study, we found that I1–9 bound to the aggregate formed by anastellin and a small FN fragment, III1–2. An engineered disulfide bond in III2, which stabilizes folding, inhibited aggregation, but a disulfide bond in III1 did not. A gelatin precipitation assay showed that I1–9 did not interact with anastellin, III1, III2, III1–2, or several III1–2 mutants including III1–2KADA. (In contrast to previous studies, we found that the III1–2KADA mutant was identical in conformation to wild-type III1–2.) Because I1–9 only bound to the aggregate and the unfolding of III2 played a role in aggregation, we generated a III2 domain that was destabilized by deletion of the G strand. This mutant bound I1–9 as shown by the gelatin precipitation assay and fluorescence resonance energy transfer analysis, and it inhibited FN matrix assembly when added to cell culture. Next, we introduced disulfide mutations into full-length FN. Three disulfide locks in III2, III3, and III11 were required to dramatically reduce anastellin-induced aggregation. When we tested the disulfide mutants in cell culture, only the disulfide bond in III2 reduced the FN matrix. These results suggest that the unfolding of III2 is one of the key factors for FN aggregation and assembly. PMID:21949131

  15. Evaluation of Verigene Blood Culture Test Systems for Rapid Identification of Positive Blood Cultures.

    PubMed

    Kim, Jae-Seok; Kang, Go-Eun; Kim, Han-Sung; Kim, Hyun Soo; Song, Wonkeun; Lee, Kyu Man

    2016-01-01

    The performance of molecular tests using the Verigene Gram-Positive and Gram-Negative Blood Culture nucleic acid tests (BC-GP and BC-GN, resp.; Naosphere, Northbrook, IL, USA) was evaluated for the identification of microorganisms detected from blood cultures. Ninety-nine blood cultures containing Gram-positive bacteria and 150 containing Gram-negative bacteria were analyzed using the BC-GP and BC-GN assays, respectively. Blood cultures were performed using the Bactec blood culture system (BD Diagnostic Systems, Franklin Lakes, NJ, USA) and conventional identification and antibiotic-susceptibility tests were performed using a MicroScan system (Siemens, West Sacramento, CA, USA). When a single strain of bacteria was isolated from the blood culture, Verigene assays correctly identified 97.9% (94/96) of Gram-positive bacteria and 93.8% (137/146) of Gram-negative bacteria. Resistance genes mecA and vanA were correctly detected by the BC-GP assay, while the extended-spectrum β-lactamase CTX-M and the carbapenemase OXA resistance gene were detected from 30 cases cultures by the BC-GN assay. The BC-GP and BC-GN assays showed high agreement with conventional identification and susceptibility tests. These tests are useful for rapid identification of microorganisms and the detection of clinically important resistance genes from positive Bactec blood cultures.

  16. Performance of Gram staining on blood cultures flagged negative by an automated blood culture system.

    PubMed

    Peretz, A; Isakovich, N; Pastukh, N; Koifman, A; Glyatman, T; Brodsky, D

    2015-08-01

    Blood is one of the most important specimens sent to a microbiology laboratory for culture. Most blood cultures are incubated for 5-7 days, except in cases where there is a suspicion of infection caused by microorganisms that proliferate slowly, or infections expressed by a small number of bacteria in the bloodstream. Therefore, at the end of incubation, misidentification of positive cultures and false-negative results are a real possibility. The aim of this work was to perform a confirmation by Gram staining of the lack of any microorganisms in blood cultures that were identified as negative by the BACTEC™ FX system at the end of incubation. All bottles defined as negative by the BACTEC FX system were Gram-stained using an automatic device and inoculated on solid growth media. In our work, 15 cultures that were defined as negative by the BACTEC FX system at the end of the incubation were found to contain microorganisms when Gram-stained. The main characteristic of most bacteria and fungi growing in the culture bottles that were defined as negative was slow growth. This finding raises a problematic issue concerning the need to perform Gram staining of all blood cultures, which could overload the routine laboratory work, especially laboratories serving large medical centers and receiving a large number of blood cultures.

  17. Evaluation of Verigene Blood Culture Test Systems for Rapid Identification of Positive Blood Cultures

    PubMed Central

    Kim, Jae-Seok; Kang, Go-Eun; Kim, Han-Sung; Song, Wonkeun; Lee, Kyu Man

    2016-01-01

    The performance of molecular tests using the Verigene Gram-Positive and Gram-Negative Blood Culture nucleic acid tests (BC-GP and BC-GN, resp.; Naosphere, Northbrook, IL, USA) was evaluated for the identification of microorganisms detected from blood cultures. Ninety-nine blood cultures containing Gram-positive bacteria and 150 containing Gram-negative bacteria were analyzed using the BC-GP and BC-GN assays, respectively. Blood cultures were performed using the Bactec blood culture system (BD Diagnostic Systems, Franklin Lakes, NJ, USA) and conventional identification and antibiotic-susceptibility tests were performed using a MicroScan system (Siemens, West Sacramento, CA, USA). When a single strain of bacteria was isolated from the blood culture, Verigene assays correctly identified 97.9% (94/96) of Gram-positive bacteria and 93.8% (137/146) of Gram-negative bacteria. Resistance genes mecA and vanA were correctly detected by the BC-GP assay, while the extended-spectrum β-lactamase CTX-M and the carbapenemase OXA resistance gene were detected from 30 cases cultures by the BC-GN assay. The BC-GP and BC-GN assays showed high agreement with conventional identification and susceptibility tests. These tests are useful for rapid identification of microorganisms and the detection of clinically important resistance genes from positive Bactec blood cultures. PMID:26904669

  18. 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%.

  19. 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.

  20. Cultural Development through Human Resource Systems Integration.

    ERIC Educational Resources Information Center

    Albert, Michael

    1985-01-01

    Discusses the framework for developing a cultural human resources management (HRM) perspective. Central to this framework is modifying HRM programs to reinforce the organization's preferred practices. Modification occurs through selection, orientation, training and development, performance appraisal, career development, and compensation and…

  1. Growing B Lymphocytes in a Three-Dimensional Culture System

    NASA Technical Reports Server (NTRS)

    Wu, J. H. David; Bottaro, Andrea

    2010-01-01

    A three-dimensional (3D) culture system for growing long-lived B lymphocytes has been invented. The capabilities afforded by the system can be expected to expand the range of options for immunological research and related activities, including testing of immunogenicity of vaccine candidates in vitro, generation of human monoclonal antibodies, and immunotherapy. Mature lymphocytes, which are the effectors of adaptive immune responses in vertebrates, are extremely susceptible to apoptotic death, and depend on continuous reception of survival-inducing stimulation (in the forms of cytokines, cell-to-cell contacts, and antigen receptor signaling) from the microenvironment. For this reason, efforts to develop systems for long-term culture of functional, non-transformed and non-activated mature lymphocytes have been unsuccessful until now. The bone-marrow microenvironment supports the growth and differentiation of many hematopoietic lineages, in addition to B-lymphocytes. Primary bone-marrow cell cultures designed to promote the development of specific cell types in vitro are highly desirable experimental systems, amenable to manipulation under controlled conditions. However, the dynamic and complex network of stromal cells and insoluble matrix proteins is disrupted in prior plate- and flask-based culture systems, wherein the microenvironments have a predominantly two-dimensional (2D) character. In 2D bone-marrow cultures, normal B-lymphoid cells become progressively skewed toward precursor B-cell populations that do not retain a normal immunophenotype, and such mature B-lymphocytes as those harvested from the spleen or lymph nodes do not survive beyond several days ex vivo in the absence of mitogenic stimulation. The present 3D culture system is a bioreactor that contains highly porous artificial scaffolding that supports the long-term culture of bone marrow, spleen, and lymph-node samples. In this system, unlike in 2D culture systems, B-cell subpopulations developing

  2. Identification of biofloc microscopic composition as the natural bioremediation in zero water exchange of Pacific white shrimp, Penaeus vannamei, culture in closed hatchery system

    NASA Astrophysics Data System (ADS)

    Manan, Hidayah; Moh, Julia Hwei Zhong; Kasan, Nor Azman; Suratman, Suhaimi; Ikhwanuddin, Mhd

    2016-06-01

    Study on the microscopic composition of biofloc in closed hatchery culture system was carried out to determine the interaction between the aggregation flocs in the bioremediation process for the decomposition and degradation of organic matter loaded in the shrimp culture tanks. The study was done for 105 days of culture period in zero water exchange. All of the organic loaded in the culture tanks identified comes from the shrimp feces, uneaten fed, and the decomposed macro- and microorganisms died in the culture tanks. All of the microscopic organisms in the biofloc were identified using Advance microscopes Nikon 80i. From the present study, there were abundances and high varieties of phytoplankton, zooplankton, protozoa, nematodes and algae species identified as aggregates together in the flocs accumulation. All of these microscopic organisms identified implemented the symbiotic process together for food supply, become the algae grazer, act as natural water stabilizer in regulating the nutrients in culture tank and serve as decomposer for dead organic matter in the water environment. Heterotrophic bacteria identified from Pseudomonas and Aeromonas family consumed the organic matter loaded at the bottom of culture tank and converted items through chemical process as useful protein food to be consumed back by the shrimp. Overall it can be concluded that the biofloc organisms identified really contributed as natural bioremediation agents in zero water exchange culture system to ensure the water quality in the optimal condition until the end of culture period.

  3. INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Aggregation Behaviors of a Two-Species System with Lose-Lose Interactions

    NASA Astrophysics Data System (ADS)

    Song, Mei-Xia; Lin, Zhen-Quan; Li, Xiao-Dong; Ke, Jian-Hong

    2010-06-01

    We propose an aggregation evolution model of two-species (A- and B-species) aggregates to study the prevalent aggregation phenomena in social and economic systems. In this model, A- and B-species aggregates perform self-exchange-driven growths with the exchange rate kernels K (k,l) = Kkl and L(k,l) = Lkl, respectively, and the two species aggregates perform self-birth processes with the rate kernels J1(k) = J1k and J2(k) = J2k, and meanwhile the interaction between the aggregates of different species A and B causes a lose-lose scheme with the rate kernel H(k,l) = Hkl. Based on the mean-field theory, we investigated the evolution behaviors of the two species aggregates to study the competitions among above three aggregate evolution schemes on the distinct initial monomer concentrations A0 and B0 of the two species. The results show that the evolution behaviors of A- and B-species are crucially dominated by the competition between the two self-birth processes, and the initial monomer concentrations A0 and B0 play important roles, while the lose-lose scheme play important roles in some special cases.

  4. A mathematical method for the 3D analysis of rotating deformable systems applied on lumen-forming MDCK cell aggregates.

    PubMed

    Marmaras, Anastasios; Berge, Ulrich; Ferrari, Aldo; Kurtcuoglu, Vartan; Poulikakos, Dimos; Kroschewski, Ruth

    2010-04-01

    Cell motility contributes to the formation of organs and tissues, into which multiple cells self-organize. However such mammalian cellular motilities are not characterized in a quantitative manner and the systemic consequences are thus unknown. A mathematical tool to decipher cell motility, accounting for changes in cell shape, within a three-dimensional (3D) cell system was missing. We report here such a tool, usable on segmented images reporting the outline of clusters (cells) and allowing the time-resolved 3D analysis of circular motility of these as parts of a system (cell aggregate). Our method can analyze circular motility in sub-cellular, cellular, multi-cellular, and also non-cellular systems for which time-resolved segmented cluster outlines are available. To exemplify, we characterized the circular motility of lumen-initiating MDCK cell aggregates, embedded in extracellular matrix. We show that the organization of the major surrounding matrix fibers was not significantly affected during this cohort rotation. Using our developed tool, we discovered two classes of circular motion, rotation and random walk, organized in three behavior patterns during lumen initiation. As rotational movements were more rapid than random walk and as both could continue during lumen initiation, we conclude that neither the class nor the rate of motion regulates lumen initiation. We thus reveal a high degree of plasticity during a developmentally critical cell polarization step, indicating that lumen initiation is a robust process. However, motility rates decreased with increasing cell number, previously shown to correlate with epithelial polarization, suggesting that migratory polarization is converted into epithelial polarization during aggregate development. PMID:20183868

  5. Differentiating sepsis from non-infectious systemic inflammation based on microvesicle-bacteria aggregation

    NASA Astrophysics Data System (ADS)

    Herrmann, I. K.; Bertazzo, S.; O'Callaghan, D. J. P.; Schlegel, A. A.; Kallepitis, C.; Antcliffe, D. B.; Gordon, A. C.; Stevens, M. M.

    2015-08-01

    Sepsis is a severe medical condition and a leading cause of hospital mortality. Prompt diagnosis and early treatment has a significant, positive impact on patient outcome. However, sepsis is not always easy to diagnose, especially in critically ill patients. Here, we present a conceptionally new approach for the rapid diagnostic differentiation of sepsis from non-septic intensive care unit patients. Using advanced microscopy and spectroscopy techniques, we measure infection-specific changes in the activity of nano-sized cell-derived microvesicles to bind bacteria. We report on the use of a point-of-care-compatible microfluidic chip to measure microvesicle-bacteria aggregation and demonstrate rapid (<=1.5 hour) and reliable diagnostic differentiation of bacterial infection from non-infectious inflammation in a double-blind pilot study. Our study demonstrates the potential of microvesicle activities for sepsis diagnosis and introduces microvesicle-bacteria aggregation as a potentially useful parameter for making early clinical management decisions.Sepsis is a severe medical condition and a leading cause of hospital mortality. Prompt diagnosis and early treatment has a significant, positive impact on patient outcome. However, sepsis is not always easy to diagnose, especially in critically ill patients. Here, we present a conceptionally new approach for the rapid diagnostic differentiation of sepsis from non-septic intensive care unit patients. Using advanced microscopy and spectroscopy techniques, we measure infection-specific changes in the activity of nano-sized cell-derived microvesicles to bind bacteria. We report on the use of a point-of-care-compatible microfluidic chip to measure microvesicle-bacteria aggregation and demonstrate rapid (<=1.5 hour) and reliable diagnostic differentiation of bacterial infection from non-infectious inflammation in a double-blind pilot study. Our study demonstrates the potential of microvesicle activities for sepsis diagnosis and

  6. Miniature Bioreactor System for Long-Term Cell Culture

    NASA Technical Reports Server (NTRS)

    Gonda, Steve R.; Kleis, Stanley J.; Geffert, Sandara K.

    2010-01-01

    A prototype miniature bioreactor system is designed to serve as a laboratory benchtop cell-culturing system that minimizes the need for relatively expensive equipment and reagents and can be operated under computer control, thereby reducing the time and effort required of human investigators and reducing uncertainty in results. The system includes a bioreactor, a fluid-handling subsystem, a chamber wherein the bioreactor is maintained in a controlled atmosphere at a controlled temperature, and associated control subsystems. The system can be used to culture both anchorage-dependent and suspension cells, which can be either prokaryotic or eukaryotic. Cells can be cultured for extended periods of time in this system, and samples of cells can be extracted and analyzed at specified intervals. By integrating this system with one or more microanalytical instrument(s), one can construct a complete automated analytical system that can be tailored to perform one or more of a large variety of assays.

  7. Sintering of highly porous silica-particle samples: analogues of early Solar-System aggregates

    NASA Astrophysics Data System (ADS)

    Poppe, T.

    2003-07-01

    I describe a new method to make particle layers which consist of SiO 2 spheres with 0.78 μm radius. The layers were produced by sedimentation of aggregates which had grown in ballistic particle collisions, and the layers had a porosity of 0.95. They were used for experiments on sintering, i.e., the samples were heated in an oven at varying temperatures and heating durations, and the samples were analyzed by scanning electron microscopy. Based on the change of particle diameter, surface diffusion sintering and viscous flow are identified as important transformation mechanisms. The first effect dominated at the start of restructuring and the latter at higher temperatures. The neck growth of adjacent particles was fitted to a surface diffusion sintering model and predicts neck radii as a heating temperature and duration function. Between the temperature range of neck formation and of melting, further restructuring occurred which lead to dissolution of particulate structure and to densification and which resulted in a porous object consisting of straight elongated substructures which connected kinks of higher material density. The thermal transformation is important for the change of strength, collisional behavior, light-scattering properties, and thermal conductivity with relevance to dust aggregates, planetesimals, comets, interplanetary dust particles, and regolith-covered celestial bodies.

  8. Composite alginate hydrogel microparticulate delivery system of zidovudine hydrochloride based on counter ion induced aggregation

    PubMed Central

    Roy, Harekrishna; Rao, P. Venkateswar; Panda, Sanjay Kumar; Biswal, Asim Kumar; Parida, Kirti Ranjan; Dash, Jharana

    2014-01-01

    Aim: The present study deals with preparation of zidovudine loaded microparticle by counter ion induced aggregation method. During this study effect of polyacrylates and hypromellose polymers on release study were investigated. Materials and Methods: The ion induced aggregated alginate based microparticles were characterized for surface morphology, particle size analysis, drug entrapment study, in-vitro study, Fourier-transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC) study. Results and Discussion: The result showed Eudragit RL-100 (ERL) based formulations had smoother surface as well as their mean particle sizes were found greater compared with Eudragit RS-100 (ERS) microparticles. Furthermore, drug entrapments were found to be more in ERL formulae as compared with ERS. RL3 released 101.05% drug over a period of 8th h and followed Higuchi profile and Fickian diffusion. Moreover, data obtained illustrated that, higher amount of quaternary ammonium group, alkali value, and glass transition temperature may be possible reason for improving permeability of ERL based formulations. It was also noticed, hyroxypropyl methylcellulose (HPMC) K4M premium grade polymer sustained drug release more than HPMC K15M. In addition, drug-excipient interaction study was carried out by FTIR and DSC study. PMID:25298940

  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. Unique cell culture systems for ground based research

    NASA Technical Reports Server (NTRS)

    Lewis, Marian L.

    1990-01-01

    The horizontally rotating fluid-filled, membrane oxygenated bioreactors developed at NASA Johnson for spacecraft applications provide a powerful tool for ground-based research. Three-dimensional aggregates formed by cells cultured on microcarrier beads are useful for study of cell-cell interactions and tissue development. By comparing electron micrographs of plant seedlings germinated during Shuttle flight 61-C and in an earth-based rotating bioreactor it is shown that some effects of microgravity are mimicked. Bioreactors used in the UAH Bioreactor Laboratory will make it possible to determine some of the effects of altered gravity at the cellular level. Bioreactors can be valuable for performing critical, preliminary-to-spaceflight experiments as well as medical investigations such as in vitro tumor cell growth and chemotherapeutic drug response; the enrichment of stem cells from bone marrow; and the effect of altered gravity on bone and muscle cell growth and function and immune response depression.

  11. Effects of biodegradable plastics on the predominant culturable bacteria associated with soil aggregate formation and stability after 9 months of incubation in natural soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An in vitro study of the effects of biodegradable plastics on the predominant soil aggregating bacteria associated to soil aggregate formation and stability after 9 months of incubation in soil. Caesar-TonThat TC, Fukui R*, Caesar AJ., Lartey, RT, and Gaskin, JF. USDA-Agricultural Research Service, ...

  12. Testing a theory of organizational culture, climate and youth outcomes in child welfare systems: a United States national study.

    PubMed

    Williams, Nathaniel J; Glisson, Charles

    2014-04-01

    Theories of organizational culture and climate (OCC) applied to child welfare systems hypothesize that strategic dimensions of organizational culture influence organizational climate and that OCC explains system variance in youth outcomes. This study provides the first structural test of the direct and indirect effects of culture and climate on youth outcomes in a national sample of child welfare systems and isolates specific culture and climate dimensions most associated with youth outcomes. The study applies multilevel path analysis (ML-PA) to a U.S. nationwide sample of 2,380 youth in 73 child welfare systems participating in the second National Survey of Child and Adolescent Well-being. Youths were selected in a national, two-stage, stratified random sample design. Youths' psychosocial functioning was assessed by caregivers' responses to the Child Behavior Checklist at intake and at 18-month follow-up. OCC was assessed by front-line caseworkers' (N=1,740) aggregated responses to the Organizational Social Context measure. Comparison of the a priori and subsequent trimmed models confirmed a reduced model that excluded rigid organizational culture and explained 70% of the system variance in youth outcomes. Controlling for youth- and system-level covariates, systems with more proficient and less resistant organizational cultures exhibited more functional, more engaged, and less stressful climates. Systems with more proficient cultures and more engaged, more functional, and more stressful climates exhibited superior youth outcomes. Findings suggest child welfare administrators can support service effectiveness with interventions that improve specific dimensions of culture and climate. PMID:24094999

  13. Testing a theory of organizational culture, climate and youth outcomes in child welfare systems: A United States national study

    PubMed Central

    Williams, Nathaniel J.; Glisson, Charles

    2013-01-01

    Theories of organizational culture and climate (OCC) applied to child welfare systems hypothesize that strategic dimensions of organizational culture influence organizational climate and that OCC explains system variance in youth outcomes. This study provides the first structural test of the direct and indirect effects of culture and climate on youth outcomes in a national sample of child welfare systems and isolates specific culture and climate dimensions most associated with youth outcomes. The study applies multilevel path analysis (ML-PA) to a U.S. nationwide sample of 2,380 youth in 73 child welfare systems participating in the second National Survey of Child and Adolescent Well-being. Youths were selected in a national, two-stage, stratified random sample design. Youths’ psychosocial functioning was assessed by caregivers’ responses to the Child Behavior Checklist at intake and at 18-month follow-up. OCC was assessed by front-line caseworkers’ (N=1,740) aggregated responses to the Organizational Social Context measure. Comparison of the a priori and subsequent trimmed models confirmed a reduced model that excluded rigid organizational culture and explained 70% of the system variance in youth outcomes. Controlling for youth- and system-level covariates, systems with more proficient and less resistant organizational cultures exhibited more functional, more engaged, and less stressful climates. Systems with more proficient cultures and more engaged, more functional, and more stressful climates exhibited superior youth outcomes. Findings suggest child welfare administrators can support service effectiveness with interventions that improve specific dimensions of culture and climate. PMID:24094999

  14. Influence of Natural Organic Matter on Aggregation, Deposition, and Transport of Fullerene Colloids in Aqueous Systems

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Rattanaudompol, U.; Powell, T.; Bouchard, D.

    2011-12-01

    Engineered fullerenes are increasingly being used in commercial products (e.g., skin and eye creams, tennis racquets, and lubricants) that may become a significant source for environmental release. A thorough understanding of fullerenes' aggregation in aqueous phase and deposition/transport in porous media is needed for evaluating the environmental persistence of fullerenes and subsequent human or ecological exposure. A number of recent studies have shown that fullerenes form stable colloidal aggregates in aqueous media and that their environmental behaviors largely depend on solution chemistry including ionic strength, solution pH, and the presence of natural organic matter (NOM). Nonetheless, the lack of systematic studies on NOM interaction with fullerene colloids and the coupling of this interaction with ionic strength and solution pH make predicting environmental behaviors of fullerenes a difficult task. In this study, electrophoretic mobility (EM), particle size, and aggregation kinetics of C60 colloidal suspensions were measured under a range of ionic strength (1.5-500.5 mM), solution pH (4, 7.8, and 10), and humic (0-9 mg C/L) or fulvic (0-11 mg C/L) acid concentrations. The EM data could be modeled with Ohshima's soft particle theory to probe thickness, softness, and charge density of adsorbed NOM layers on fullerene colloids. Under select conditions that represent low and high mobility, deposition studies using a quartz crystal microbalance and transport experiments in saturated and unsaturated sand columns will be conducted. It is anticipated that NOM may alter the transport of fullerene C60 differently in unsaturated media compared with saturated media. Our preliminary results showed that humic acid is more effective than fulvic acid in stabilizing fullerene suspensions and the extent of this stabilizing effect is a function of ionic strength when buffered at pH 7.8 with 0.5 mM NaHCO3. The findings of this study will help better assess the fate and

  15. Evaluation of the effects of amyloid β aggregation from seaweed extracts by a microliter-scale high-throughput screening system with a quantum dot nanoprobe.

    PubMed

    Ogara, Toshiki; Takahashi, Tomohito; Yasui, Hajime; Uwai, Koji; Tokuraku, Kiyotaka

    2015-07-01

    Inhibitors of amyloid β (Aβ) aggregation have the potential to serve as lead compounds for anti-Alzheimer's disease (AD) agents because Aβ aggregation is a key step in AD pathogenesis. Recently, we developed a novel microliter-scale high-throughput screening (MSHTS) system for Aβ aggregation inhibitors that applied fluorescence microscopic analysis with quantum dot nanoprobes, and attempted to comprehensively screen the inhibitors from spices using this system (Ishigaki et al., PLoS One, 8, e72992, 2013). In this study, we tried to evaluate the inhibitory activities of 11 seaweed extracts on Aβ aggregation using the MSHTS system. The half-maximal effective concentration (EC50) of the ethanolic extracts from all seaweeds exceeded 4.9 mg/ml, indicating that the extracts inhibit Aβ aggregation although this activity was significantly lower than that displayed by members of the Lamiaceae, a family of herbal spices that showed highest activity among 52 spices tested in our 2013 study. On the other hand, the EC50 of boiling water extracts was 0.013-0.42 mg/ml which was comparable with the EC50 of the extracts from the Lamiaceae family. These results suggest that the extraction efficiency of the inhibitors by boiling water extraction was higher than that by ethanolic extraction. Moreover, analysis of fluorescence micrographs, which were obtained from the MSHTS system, revealed that the morphology of the Aβ aggregates coincubated with boiling water extracts differed from control aggregates, suggesting that the MSHTS system is also useful for screening substances that affect the morphology of aggregates.

  16. Seven essential strategies for promoting and sustaining systemic cultural competence.

    PubMed

    Delphin-Rittmon, Miriam E; Andres-Hyman, Raquel; Flanagan, Elizabeth H; Davidson, Larry

    2013-03-01

    Racial and ethnic disparities are disturbing facets of the American healthcare system that document the reality of unequal treatment. Research consistently shows that patients of color experience poorer quality of care and health outcomes contributing to increased risks and accelerated mortality rates relative to their white counterparts. While initially conceptualized as an approach for increasing the responsiveness of children's behavioral health care, cultural competence has been adopted as a key strategy for eliminating racial and ethnic health disparities across the healthcare system. However, cultural competence research and practices largely focus on improving provider competencies, while agency and system level approaches for meeting the service needs of diverse populations are given less attention. In this article we offer seven essential strategies for promoting and sustaining organizational and systemic cultural competence. These strategies are to: (1) Provide executive level support and accountability, (2) Foster patient, community and stakeholder participation and partnerships, (3) Conduct organizational cultural competence assessments, (4) Develop incremental and realistic cultural competence action plans, (5) Ensure linguistic competence, (6) Diversify, develop, and retain a culturally competent workforce, and (7) Develop an agency or system strategy for managing staff and patient grievances. For each strategy we offer several recommendations for implementation. PMID:22581030

  17. Seven essential strategies for promoting and sustaining systemic cultural competence.

    PubMed

    Delphin-Rittmon, Miriam E; Andres-Hyman, Raquel; Flanagan, Elizabeth H; Davidson, Larry

    2013-03-01

    Racial and ethnic disparities are disturbing facets of the American healthcare system that document the reality of unequal treatment. Research consistently shows that patients of color experience poorer quality of care and health outcomes contributing to increased risks and accelerated mortality rates relative to their white counterparts. While initially conceptualized as an approach for increasing the responsiveness of children's behavioral health care, cultural competence has been adopted as a key strategy for eliminating racial and ethnic health disparities across the healthcare system. However, cultural competence research and practices largely focus on improving provider competencies, while agency and system level approaches for meeting the service needs of diverse populations are given less attention. In this article we offer seven essential strategies for promoting and sustaining organizational and systemic cultural competence. These strategies are to: (1) Provide executive level support and accountability, (2) Foster patient, community and stakeholder participation and partnerships, (3) Conduct organizational cultural competence assessments, (4) Develop incremental and realistic cultural competence action plans, (5) Ensure linguistic competence, (6) Diversify, develop, and retain a culturally competent workforce, and (7) Develop an agency or system strategy for managing staff and patient grievances. For each strategy we offer several recommendations for implementation.

  18. Aggregated Modeling of Thermostatic Loads in Demand Response: A Systems and Control Perspective

    SciTech Connect

    Kalsi, Karanjit; Chassin, Forrest S.; Chassin, David P.

    2011-12-12

    Demand response is playing an increasingly important role in smart grid research and technologies being examined in recently undertaken demonstration projects. The behavior of load as it is affected by various load control strategies is important to understanding the degree to which different classes of end-use load can contribute to demand response programs at various times. This paper focuses on developing aggregated models for a homogeneous population of thermostatically controlled loads. The different types of loads considered in this paper include, but are not limited to, water heaters and HVAC units. The effects of demand response and user over-ride on the load population dynamics are investigated. The controllability of the developed lumped models is validated which forms the basis for designing different control strategies.

  19. Development of Scalable Culture Systems for Human Embryonic Stem Cells

    PubMed Central

    Azarin, Samira M.; Palecek, Sean P.

    2009-01-01

    The use of human pluripotent stem cells, including embryonic and induced pluripotent stem cells, in therapeutic applications will require the development of robust, scalable culture technologies for undifferentiated cells. Advances made in large-scale cultures of other mammalian cells will facilitate expansion of undifferentiated human embryonic stem cells (hESCs), but challenges specific to hESCs will also have to be addressed, including development of defined, humanized culture media and substrates, monitoring spontaneous differentiation and heterogeneity in the cultures, and maintaining karyotypic integrity in the cells. This review will describe our current understanding of environmental factors that regulate hESC self-renewal and efforts to provide these cues in various scalable bioreactor culture systems. PMID:20161686

  20. Aggregation in environmental systems: seasonal tracer cycles quantify young water fractions, but not mean transit times, in spatially heterogeneous catchments

    NASA Astrophysics Data System (ADS)

    Kirchner, J. W.

    2015-03-01

    Environmental heterogeneity is ubiquitous, but environmental systems are often analyzed as if they were homogeneous instead, resulting in aggregation errors that are rarely explored and almost never quantified. Here I use simple benchmark tests to explore this general problem in one specific context: the use of seasonal cycles in chemical or isotopic tracers (such as Cl-, δ18O, or δ2H) to estimate timescales of storage in catchments. Timescales of catchment storage are typically quantified by the mean transit time, meaning the average time that elapses between parcels of water entering as precipitation and leaving again as streamflow. Longer mean transit times imply greater damping of seasonal tracer cycles. Thus, the amplitudes of tracer cycles in precipitation and streamflow are commonly used to calculate catchment mean transit times. Here I show that these calculations will typically be wrong by several hundred percent, when applied to catchments with realistic degrees of spatial heterogeneity. This aggregation bias arises from the strong nonlinearity in the relationship between tracer cycle amplitude and mean travel time. I propose an alternative storage metric, the young water fraction in streamflow, defined as the fraction of runoff with transit times of less than roughly 0.2 years. I show that this young water fraction (not to be confused with event-based "new water" in hydrograph separations) is accurately predicted by seasonal tracer cycles within a precision of a few percent, across the entire range of mean transit times from almost zero to almost infinity. Importantly, this relationship is also virtually free from aggregation error. That is, seasonal tracer cycles also accurately predict the young water fraction in runoff from highly heterogeneous mixtures of subcatchments with strongly contrasting transit time distributions. Thus, although tracer cycle amplitudes yield biased and unreliable estimates of catchment mean travel times in heterogeneous

  1. A model for the kinetics of homotypic cellular aggregation under static conditions

    NASA Technical Reports Server (NTRS)

    Neelamegham, S.; Munn, L. L.; Zygourakis, K.; McIntire, L. V. (Principal Investigator)

    1997-01-01

    We present the formulation and testing of a mathematical model for the kinetics of homotypic cellular aggregation. The model considers cellular aggregation under no-flow conditions as a two-step process. Individual cells and cell aggregates 1) move on the tissue culture surface and 2) collide with other cells (or aggregates). These collisions lead to the formation of intercellular bonds. The aggregation kinetics are described by a system of coupled, nonlinear ordinary differential equations, and the collision frequency kernel is derived by extending Smoluchowski's colloidal flocculation theory to cell migration and aggregation on a two-dimensional surface. Our results indicate that aggregation rates strongly depend upon the motility of cells and cell aggregates, the frequency of cell-cell collisions, and the strength of intercellular bonds. Model predictions agree well with data from homotypic lymphocyte aggregation experiments using Jurkat cells activated by 33B6, an antibody to the beta 1 integrin. Since cell migration speeds and all the other model parameters can be independently measured, the aggregation model provides a quantitative methodology by which we can accurately evaluate the adhesivity and aggregation behavior of cells.

  2. Strengths and limitations of the neurosphere culture system.

    PubMed

    Jensen, Josephine B; Parmar, Malin

    2006-12-01

    After the initial reports of free-floating cultures of neural stem cells termed neurospheres (1,2), a wide array of studies using this promising culture system emerged. In theory, this was a near-perfect system for large-scale production of neural cells for use in cell replacement therapies and to assay for and characterize neural stem cells. More than a decade later, after rigorous scrutiny and ample experimental testing of the neurosphere culture system, it has become apparent that the culture system suffers from several disadvantages, and its usefulness is limited for several applications. Nevertheless, the bulk of high-quality research produced over the last decade has also shown that under the right circumstances and for the appropriate purposes, neurospheres hold up to their initial promise. This article discusses the pros and cons of the neurosphere culture system regarding its three major applications: as an assay for neural stem cells, as a model system for neurogenesis and neural development, and for expansion of neural stem cells for transplantation purposes.

  3. Cultural selection drives the evolution of human communication systems.

    PubMed

    Tamariz, Monica; Ellison, T Mark; Barr, Dale J; Fay, Nicolas

    2014-08-01

    Human communication systems evolve culturally, but the evolutionary mechanisms that drive this evolution are not well understood. Against a baseline that communication variants spread in a population following neutral evolutionary dynamics (also known as drift models), we tested the role of two cultural selection models: coordination- and content-biased. We constructed a parametrized mixed probabilistic model of the spread of communicative variants in four 8-person laboratory micro-societies engaged in a simple communication game. We found that selectionist models, working in combination, explain the majority of the empirical data. The best-fitting parameter setting includes an egocentric bias and a content bias, suggesting that participants retained their own previously used communicative variants unless they encountered a superior (content-biased) variant, in which case it was adopted. This novel pattern of results suggests that (i) a theory of the cultural evolution of human communication systems must integrate selectionist models and (ii) human communication systems are functionally adaptive complex systems.

  4. Therapeutically important proteins from in vitro plant tissue culture systems.

    PubMed

    Doran, Pauline M

    2013-01-01

    Plant cells cultured in liquid medium in bioreactors are now being used commercially to produce biopharmaceutical proteins. The emergence of in vitro plant cell culture as a production vehicle reflects the importance of key biosafety and biocontainment concerns affecting the competitiveness of alternative systems such as mammalian cell culture and agriculture. Food plant species are particularly attractive as hosts for in vitro protein production: the risk of transgene escape and food chain contamination is eliminated using containment facilities, while regulatory approval for oral delivery of drugs may be easier than if non-edible species were used. As in whole plants, proteolysis in cultured plant cells can lead to significant degradation of foreign proteins after synthesis; however, substantial progress has been made to counter the destructive effects of proteases in plant systems. Although protein secretion into the culture medium is advantageous for product recovery and purification, measures are often required to minimise extracellular protease activity and product losses due to irreversible surface adsorption. Disposable plastic bioreactors, which are being used increasingly in mammalian cell bioprocessing, are also being adopted for plant cell culture to allow rapid scale-up and generation of saleable product. This review examines a range of technical and regulatory issues affecting the choice of industrial production platform for foreign proteins, and assesses progress in the development of in vitro plant systems for biopharmaceutical production. PMID:23210789

  5. Submillimetre-sized dust aggregate collision and growth properties. Experimental study of a multi-particle system on a suborbital rocket

    NASA Astrophysics Data System (ADS)

    Brisset, J.; Heißelmann, D.; Kothe, S.; Weidling, R.; Blum, J.

    2016-08-01

    Context. In the very first steps of the formation of a new planetary system, dust agglomerates grow inside the protoplanetary disk that rotates around the newly formed star. In this disk, collisions between the dust particles, induced by interactions with the surrounding gas, lead to sticking. Aggregates start growing until their sizes and relative velocities are high enough for collisions to result in bouncing or fragmentation. With the aim of investigating the transitions between sticking and bouncing regimes for colliding dust aggregates and the formation of clusters from multiple aggregates, the Suborbital Particle and Aggregation Experiment (SPACE) was flown on the REXUS 12 suborbital rocket. Aims: The collisional and sticking properties of sub-mm-sized aggregates composed of protoplanetary dust analogue material are measured, including the statistical threshold velocity between sticking and bouncing, their surface energy and tensile strength within aggregate clusters. Methods: We performed an experiment on the REXUS 12 suborbital rocket. The protoplanetary dust analogue materials were micrometre-sized monodisperse and polydisperse SiO2 particles prepared into aggregates with sizes around 120 μm and 330 μm, respectively and volume filling factors around 0.37. During the experimental run of 150 s under reduced gravity conditions, the sticking of aggregates and the formation and fragmentation of clusters of up to a few millimetres in size was observed. Results: The sticking probability of the sub-mm-sized dust aggregates could be derived for velocities decreasing from ~22 to 3 cm s-1. The transition from bouncing to sticking collisions happened at 12.7+2.1-1.4 cm s-1 for the smaller aggregates composed of monodisperse particles and at 11.5+1.9-1.3 and 11.7+1.9-1.3 cm s-1 for the larger aggregates composed of mono- and polydisperse dust particles, respectively. Using the pull-off force of sub-mm-sized dust aggregates from the clusters, the surface energy of the

  6. Method and system of culturing an algal mat

    DOEpatents

    Das, Keshav C; Cannon, Benjamin R; Bhatnagar, Ashish; Chinnasamy, Senthil

    2014-05-13

    A system and method for culturing algae are presented. The system and method utilize a fog of growth medium that is delivered to an algal mat generator along with a stream of CO.sub.2 to promote growth of algal cells contained in the generator.

  7. 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.

  8. 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.

  9. 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.

  10. Development of a genetic system for Marinobacter adhaerens HP15 involved in marine aggregate formation by interacting with diatom cells.

    PubMed

    Sonnenschein, Eva C; Gärdes, Astrid; Seebah, Shalin; Torres-Monroy, Ingrid; Grossart, Hans-Peter; Ullrich, Matthias S

    2011-11-01

    Diatom aggregation is substantial for organic carbon flux from the photic zone to deeper waters. Many heterotrophic bacteria ubiquitously found in diverse marine environments interact with marine algae and thus impact organic matter and energy cycling in the ocean. In particular, Marinobacter adhaerens HP15 induces aggregate formation while interacting with the diatom, Thalassiosira weissflogii. To study this effect at the molecular level, a genetic tool system was developed for strain HP15. The antibiotic susceptibility spectrum of this organism was determined and electroporation and conjugation protocols were established. Among various plasmids of different incompatibility groups, only two were shown to replicate in M. adhaerens. 1.4×10(-3) transconjugants per recipient were obtained for a broad-host-range vector. Electroporation efficiency corresponded to 1.1×10(5)CFU per μg of DNA. Transposon and gene-specific mutageneses were conducted for flagellum biosynthetic genes. Mutant phenotypes were confirmed by swimming assay and microscopy. Successful expression of two reporter genes in strain HP15 revealed useful tools for gene expression analyses, which will allow studying diverse bacteria-algae interactions at the molecular level and hence to gain a mechanistic understanding of micro-scale processes underlying ocean basin-scale processes. This study is the first report for the genetic manipulation of a Marinobacter species which specifically interacts with marine diatoms and serves as model to additionally analyze various previously reported Marinobacter-algae interactions in depth. PMID:21880271

  11. Development of a genetic system for Marinobacter adhaerens HP15 involved in marine aggregate formation by interacting with diatom cells.

    PubMed

    Sonnenschein, Eva C; Gärdes, Astrid; Seebah, Shalin; Torres-Monroy, Ingrid; Grossart, Hans-Peter; Ullrich, Matthias S

    2011-11-01

    Diatom aggregation is substantial for organic carbon flux from the photic zone to deeper waters. Many heterotrophic bacteria ubiquitously found in diverse marine environments interact with marine algae and thus impact organic matter and energy cycling in the ocean. In particular, Marinobacter adhaerens HP15 induces aggregate formation while interacting with the diatom, Thalassiosira weissflogii. To study this effect at the molecular level, a genetic tool system was developed for strain HP15. The antibiotic susceptibility spectrum of this organism was determined and electroporation and conjugation protocols were established. Among various plasmids of different incompatibility groups, only two were shown to replicate in M. adhaerens. 1.4×10(-3) transconjugants per recipient were obtained for a broad-host-range vector. Electroporation efficiency corresponded to 1.1×10(5)CFU per μg of DNA. Transposon and gene-specific mutageneses were conducted for flagellum biosynthetic genes. Mutant phenotypes were confirmed by swimming assay and microscopy. Successful expression of two reporter genes in strain HP15 revealed useful tools for gene expression analyses, which will allow studying diverse bacteria-algae interactions at the molecular level and hence to gain a mechanistic understanding of micro-scale processes underlying ocean basin-scale processes. This study is the first report for the genetic manipulation of a Marinobacter species which specifically interacts with marine diatoms and serves as model to additionally analyze various previously reported Marinobacter-algae interactions in depth.

  12. Tailored electronic structure and optical properties of conjugated systems through aggregates and dipole-dipole interactions.

    PubMed

    Park, Young Il; Kuo, Cheng-Yu; Martinez, Jennifer S; Park, Young-Shin; Postupna, Olena; Zhugayevych, Andriy; Kim, Seungho; Park, Jongwook; Tretiak, Sergei; Wang, Hsing-Lin

    2013-06-12

    A series of PPVO (p-phenylene vinylene oligomer) derivatives with functional groups of varying electronegativity were synthesized via the Horner-Wadsworth-Emmons reaction. Subtle changes in the end group functionality significantly impact the molecular electronic and optical properties of the PPVOs, resulting in broadly tunable and efficient UV absorption and photoluminescence spectra. Of particular interest is the NO2-substituted PPVO which exhibits photoluminescence color ranging from the blue to the red, thus encompassing the entire visible spectrum. Our experimental study and electronic structure calculations suggest that the formation of aggregates and strong dipole-dipole solute-solvent interactions are responsible for the observed strong solvatochromism. Experimental and theoretical results for the NH2-, H-, and NO2-substituted PPVOs suggest that the stabilization of ground or excited state dipoles leads to the blue or red shift of the optical spectra. The electroluminescence (EL) spectra of H-, COOH-, and NO2-PPVO have maxima at 487, 518, and 587 nm, respectively, in the OLED device. This trend in the EL spectra is in excellent agreement with the end group-dependent PL spectra of the PPVO thin-films. PMID:23607446

  13. Excitonic Relaxation and Coherent Vibrational Dynamics in Zinc Chlorin Aggregates for Artificial Photosynthetic Systems.

    PubMed

    Han, Dongjia; Du, Juan; Kobayashi, Takayoshi; Miyatake, Tomohiro; Tamiaki, Hitoshi; Li, Yanyan; Leng, Yuxin

    2015-09-17

    The excitonic relaxation and coherent vibrational dynamics in stairlike zinc chlorin aggregates prepared for mimicking chlorosome in nature have been studied simultaneously by 6.8 fs real-time vibrational laser spectroscopy. The relaxation from Q-exciton state to the dark nonfluorescent charge-transfer (CT) state is determined to be 850 ± 70 fs. The spectral distribution of the molecular vibrational amplitude has been discussed in terms of the difference in the equilibrium positions of potential curves between the ground state and the excited state. Since the displacement in the coordinate space from the potential minimum of the ground state to that of the excited states is small, coherent oscillations generated by the impulsive excitation are strongest where the slope of the excitonic resonance is largest. Consequently, the probe wavelength dependence of the amplitude modulation follows the first derivative of the excitonic resonance, and π phase jump has been observed. Excitonic transition energy modulation caused by the coherent molecular vibrations has also been studied, and the vibrational mode with a low frequency of 146 cm(-1) is found to play a dominating role in the transition energy shift effect.

  14. Excitonic Relaxation and Coherent Vibrational Dynamics in Zinc Chlorin Aggregates for Artificial Photosynthetic Systems.

    PubMed

    Han, Dongjia; Du, Juan; Kobayashi, Takayoshi; Miyatake, Tomohiro; Tamiaki, Hitoshi; Li, Yanyan; Leng, Yuxin

    2015-09-17

    The excitonic relaxation and coherent vibrational dynamics in stairlike zinc chlorin aggregates prepared for mimicking chlorosome in nature have been studied simultaneously by 6.8 fs real-time vibrational laser spectroscopy. The relaxation from Q-exciton state to the dark nonfluorescent charge-transfer (CT) state is determined to be 850 ± 70 fs. The spectral distribution of the molecular vibrational amplitude has been discussed in terms of the difference in the equilibrium positions of potential curves between the ground state and the excited state. Since the displacement in the coordinate space from the potential minimum of the ground state to that of the excited states is small, coherent oscillations generated by the impulsive excitation are strongest where the slope of the excitonic resonance is largest. Consequently, the probe wavelength dependence of the amplitude modulation follows the first derivative of the excitonic resonance, and π phase jump has been observed. Excitonic transition energy modulation caused by the coherent molecular vibrations has also been studied, and the vibrational mode with a low frequency of 146 cm(-1) is found to play a dominating role in the transition energy shift effect. PMID:26307640

  15. Aggregation in environmental systems: catchment mean transit times and young water fractions under hydrologic nonstationarity

    NASA Astrophysics Data System (ADS)

    Kirchner, J. W.

    2015-03-01

    Methods for estimating mean transit times from chemical or isotopic tracers (such as Cl-, δ18O, or δ2H) commonly assume that catchments are stationary (i.e. time-invariant) and homogeneous. Real catchments are neither. In a companion paper, I showed that catchment mean transit times estimated from seasonal tracer cycles are highly vulnerable to aggregation error, exhibiting strong bias and large scatter in spatially heterogeneous catchments. I proposed a different measure of transit times, the young water fraction, and showed that it is virtually immune to aggregation error under spatial heterogeneity. Here I extend this analysis by exploring how nonstationarity affects mean transit times and young water fractions estimated from seasonal tracer cycles, using benchmark tests based on a simple two-box model. The model exhibits complex nonstationary behavior, with striking volatility in tracer concentrations, young water fractions, and mean transit times, driven by rapid shifts in the mixing ratios of fluxes from the upper and lower boxes. The transit-time distribution in streamflow becomes increasingly skewed at higher discharges, with marked increases in the young water fraction and decreases in the mean water age, reflecting the increased dominance of the upper box at higher flows. Even this simple two-box model exhibits strong equifinality; hydrograph calibration cannot constrain four of its five parameters. This equifinality problem can be partly resolved by simple parameter transformations. However, transit times are primarily determined by residual storage, which cannot be constrained through hydrograph calibration and must instead be estimated by tracer behavior. Seasonal tracer cycles in the two-box model are very poor predictors of mean transit times, with typical errors of several hundred percent. However, the same tracer cycles predict young water fractions within a few percent, even in model catchments that are both nonstationary and spatially

  16. Culture and systems of oppression in abused women's lives.

    PubMed

    Phillips, D S

    1998-01-01

    Women's experiences of abuse are shaped by the social and cultural contexts in which they live. Recognition of the complex ways in which culture and systems of oppression interact, creating qualitatively different abuse experiences, is important nursing knowledge. Of particular concern are the ways in which women are constrained in their efforts to combat abuse as they experience the harsh and alienating effects of racism, sexism, classism, and other forms of social injustice. An understanding of the ways in which race and ethnicity, class, language and citizenship, religion, and culture intersect and shape women's experiences of abuse is critical to the provision of culturally competent nursing care. This understanding is the springboard from which more effective assessment and intervention strategies with vulnerable abused women of diverse backgrounds can emerge.

  17. Horizontally rotated cell culture system with a coaxial tubular oxygenator

    NASA Technical Reports Server (NTRS)

    Wolf, David A. (Inventor); Schwarz, Ray P. (Inventor); Trinh, Tinh T. (Inventor)

    1991-01-01

    The present invention relates to a horizontally rotating bioreactor useful for carrying out cell and tissue culture. For processing of mammalian cells, the system is sterilized and fresh fluid medium, microcarrier beads, and cells are admitted to completely fill the cell culture vessel. An oxygen containing gas is admitted to the interior of the permeable membrane which prevents air bubbles from being introduced into the medium. The cylinder is rotated at a low speed within an incubator so that the circular motion of the fluid medium uniformly suspends the microbeads throughout the cylinder during the cell growth period. The unique design of this cell and tissue culture device was initially driven by two requirements imposed by its intended use for feasibility studies for three dimensional culture of living cells and tissues in space by JSC. They were compatible with microgravity and simulation of microgravity in one G. The vessels are designed to approximate the extremely quiescent low shear environment obtainable in space.

  18. 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).

  19. Effective viscoplastic behavior of polycrystalline aggregates lacking four independent slip systems inferred from homogenization methods; application to olivine

    NASA Astrophysics Data System (ADS)

    Detrez, F.; Castelnau, O.; Cordier, P.; Merkel, S.; Raterron, P.

    2015-10-01

    Polycrystalline aggregates lacking four independent systems for the glide of dislocations can deform in a purely viscoplastic regime only if additional deformation mechanisms (such as grain boundary sliding and diffusion) are activated. We introduce an implementation of the self-consistent scheme in which this additional physical mechanism, considered as a stress relaxation mechanism, is represented by a nonlinear isotropic viscoplastic potential. Several nonlinear extensions of the self-consistent scheme, including the second-order method of Ponte-Castañeda, are used to provide an estimate of the effective viscoplastic behavior of such polycrystals. The implementation of the method includes an approximation of the isotropic potential to ensure convergence of the attractive fixed-point numerical algorithm. The method is then applied to olivine polycrystals, the main constituent of the Earth's upper mantle. Due to the extreme local anisotropy of the local constitutive behavior and the subsequent intraphase stress and strain-rate field heterogeneities, the second-order method is the only extension providing qualitative and quantitative accurate results. The effective viscosity is strongly dependent on the strength of the relaxation mechanism. For olivine, a linear viscous relaxation (e.g. diffusion) could be relevant; in that case, the polycrystal stress sensitivity is reduced compared to that of dislocation glide, and the most active slip system is not necessarily the one with the smallest reference stress due to stress concentrations. This study reveals the significant importance of the strength and stress sensitivity of the additional relaxation mechanism for the rheology and lattice preferred orientation in such highly anisotropic polycrystalline aggregates.

  20. Culturally competent systems of care with Latino children and families.

    PubMed

    Dettlaff, Alan J; Rycraft, Joan R

    2009-01-01

    The Latino population represents the fastest growing ethnic minority in the United States. As a result, child welfare agencies need to be prepared to provide culturally appropriate services to Latino families. This paper describes an evaluation of a federally funded initiative designed to train child welfare practitioners in using an existing evidence-based framework--systems of care--with Latino children and families to address the need for culturally competent, community-based services with this population. Results indicate that trained participants responded positively to the systems of care framework, increased their knowledge of systems of care, and reported positive benefits to their clients through using this framework. However, challenges to implementing systems of care were identified. Implications of these findings and the use of systems of care in child welfare are presented.

  1. Developing defined culture systems for human pluripotent stem cells

    PubMed Central

    Valamehr, Bahram; Tsutsui, Hideaki; Ho, Chih-Ming; Wu, Hong

    2013-01-01

    Human pluripotent stem cells hold promising potential in many therapeutics applications including regenerative medicine and drug discovery. Over the past three decades, embryonic stem cell research has illustrated that embryonic stem cells possess two important and distinct properties: the ability to continuously self-renew and the ability to differentiate into all specialized cell types. In this article, we will discuss the continuing evolution of human pluripotent stem cell culture by examining requirements needed for the maintenance of self-renewal in vitro. We will also elaborate on the future direction of the field toward generating a robust and completely defined culture system, which has brought forth collaborations amongst biologists and engineers. As human pluripotent stem cell research progresses towards identifying solutions for debilitating diseases, it will be critical to establish a defined, reproducible and scalable culture system to meet the requirements of these clinical applications. PMID:21916597

  2. The effect of three culture methods on intensive culture system of pacific white shrimp ( Litopenaeus vannamei)

    NASA Astrophysics Data System (ADS)

    Ma, Zhen; Wan, Rong; Song, Xiefa; Gao, Lei

    2013-09-01

    Different culture methods may affect the intensive culture system of Pacific white shrimp ( Litopenaeus vannamei) regarding water quality and growth and economic performance. This study evaluated the potential effects of three culture methods through cultivation of juvenile shrimps under consistent tank management conditions for 84 d. The three methods involved shrimp cultivation in different tanks, i.e., outdoor tanks with cement bottom (mode-C), greenhouse tanks with cement bottom (mode-G) and outdoor tanks with mud-substrate (mode-M). Results showed that water temperature was significantly higher in mode-G than that in mode-C ( P < 0.05). In contrast to the other two treatments, mode-M had stable pH after 50 d cultivation of shrimps. In the mid-late period, the average concentrations of TAN, NO2-N, DIP and COD were significantly lower in mode-M and mode-G compared with those in mode-C ( P < 0.05). Despite lack of differences in the final shrimp weight among different treatments ( P > 0.05), mode-M had significantly higher shrimp yield, survival rate and feed conversion rate ( P < 0.05) than other modes. There were significant differences in revenue and net return among different treatments ( P < 0.05). These demonstrated that the treatments of mode-G and mode-M were conductive to the intensive culture system of L. vannamei.

  3. Moving Towards Culturally Competent Health Systems: Organizational and Market Factors

    PubMed Central

    Weech-Maldonado, Robert; Elliott, Marc; Pradhan, Rohit; Schiller, Cameron; Dreachslin, Janice; Hays, Ron D.

    2012-01-01

    Cultural competency has been proposed as an organizational strategy to address racial/ethnic disparities in the health care system; disparities are a long-standing policy challenge whose relevance is only increasing with the increasing population diversity of the US and across the world. Using an integrative conceptual framework based on the resource dependency and institutional theories, we examine the relationship between organizational and market factors and hospitals’ degree of cultural competency. Our sample consists of 119 hospitals located in the state of California (US) and is constructed using the following datasets for the year 2006: Cultural Competency Assessment Tool of Hospitals (CCATH) Survey, California’s Office of Statewide Health Planning & Development’s Hospital Inpatient Discharges and Annual Hospital Financial Data, American Hospital Association’s Annual Survey, and the Area Resource File. The dependent variable consists of the degree of hospital cultural competency, as assessed by the CCATH overall score. Organizational variables include ownership status, teaching hospital, payer mix, size, system membership, financial performance, and the proportion of inpatient racial/ethnic minorities. Market characteristics included hospital competition, the proportion of racial/ethnic minorities in the area, metropolitan area, and per capita income. Regression analyses were conducted to assess the relationship between the CCATH overall score and organizational and market variables. Our results show that hospitals which are not-for-profit, serve a more diverse inpatient population, and are located in more competitive and affluent markets exhibit a higher degree of cultural competency. Our results underscore the importance of both institutional and competitive market pressures in guiding hospital behavior. For instance, while not-for-profit may adopt innovative/progressive policies like cultural competency simply as a function of their organizational

  4. Optimization of Buffalo (Bubalus bubalis) Embryonic Stem Cell Culture System

    PubMed Central

    Zandi, Mohammad; Muzaffar, Musharifa; Shah, Syed Mohmad; Kumar Singh, Manoj; Palta, Prabhat; Kumar Singla, Suresh; Manik, Radheysham; Chauhan, Manmohan Singh

    2015-01-01

    Objective In order to retain an undifferentiated pluripotent state, embryonic stem (ES) cells have to be cultured on feeder cell layers. However, use of feeder layers limits stem cell research, since experimental data may result from a combined ES cell and feeder cell response to various stimuli. Materials and Methods In this experimental study, a buffalo ES cell line was established from in vitro derived blastocysts and characterized by the Alkaline phosphatase (AP) and immunoflourescence staining of various pluripotency markers. We examined the effect of various factors like fibroblast growth factor 2 (FGF-2), leukemia inhibitory factor (LIF) and Y-27632 to support the growth and maintenance of bubaline ES cells on gelatin coated dishes, in order to establish feeder free culture systems. We also analyzed the effect of feeder-conditioned media on stem cell growth in gelatin based cultures both in the presence as well as in the absence of the growth factors. Results The results showed that Y-27632, in the presence of FGF-2 and LIF, resulted in higher colony growth and increased expression of Nanog gene. Feeder-Conditioned Medium resulted in a significant increase in growth of buffalo ES cells on gelatin coated plates, however, feeder layer based cultures produced better results than gelatin based cultures. Feeder layers from buffalo fetal fibroblast cells can support buffalo ES cells for more than two years. Conclusion We developed a feeder free culture system that can maintain buffalo ES cells in the short term, as well as feeder layer based culture that can support the long term maintenance of buffalo ES cells. PMID:26199905

  5. Parents' Cultural Belief Systems: Their Origins, Expressions, and Consequences.

    ERIC Educational Resources Information Center

    Harkness, Sara, Ed.; Super, Charles M., Ed.

    This volume presents observations and thinking of scholars from a variety of disciplines about parental cultural belief systems. The chapters are concerned with the sources and consequences of parental ethnotheories in a number of societies. The following chapters are included: (1) "Introduction" (Sara Harkness and Charles M. Super); (2) "Parents'…

  6. Cultural Influences on Number Preferences: Christmas and Grading Systems

    ERIC Educational Resources Information Center

    Stieger, Stefan; Krizan, Zlatan

    2013-01-01

    People consistently prefer numbers associated with themselves (e.g., birth dates) over other numbers. We argue that such number preferences are also shaped by cultural influences, such as customs regarding the day on which Christmas is celebrated and customs regarding ranking of numerals used in national school's grading system. Across 6 different…

  7. World Culture in the Capitalist World-System in Transition

    ERIC Educational Resources Information Center

    Griffiths, Tom G.; Arnove, Robert F.

    2015-01-01

    World culture theory (WCT) offers an explanatory framework for macro-level comparative analyses of systems of mass education, including their structures, accompanying policies and their curricular and pedagogical practices. WCT has contributed to broader efforts to overcome methodological nationalism in comparative research. In this paper, we…

  8. Pedagogical System of Future Teachers' Professional Thinking Culture Formation

    ERIC Educational Resources Information Center

    Abildina, Saltanat K.; Sarsekeyeva, Zhanar Y.; Aidarbekova, Kulzhan A.; Asetova, Zhannur B.; Adanov, Kuanysbek B.

    2016-01-01

    Research objective is to theoretically justify and to develop a pedagogical system of development of future teachers' professional thinking culture. In the research there are used a set of theoretical methods: systematic analysis of the philosophical, psychological and pedagogical literature on the researched topic; compilation and classification…

  9. Barriers to Excellence: The Culture of Silence in School Systems.

    ERIC Educational Resources Information Center

    Rusch, Edith A.

    Little is known about how restructuring networks actually affect the cultures of school systems. This report examines the creation of an "island" of reform in a school district in northwest Ohio. The research emanated from the discovery of a new "island" in northwest Ohio called the Pathfinder Network. The group formed through like-minded…

  10. Multilineage differentiation of rhesus monkey embryonic stem cells in three-dimensional culture systems.

    PubMed

    Chen, Silvia S; Revoltella, Roberto P; Papini, Sandra; Michelini, Monica; Fitzgerald, Wendy; Zimmerberg, Joshua; Margolis, Leonid

    2003-01-01

    In the course of normal embryogenesis, embryonic stem (ES) cells differentiate along different lineages in the context of complex three-dimensional (3D) tissue structures. In order to study this phenomenon in vitro under controlled conditions, 3D culture systems are necessary. Here, we studied in vitro differentiation of rhesus monkey ES cells in 3D collagen matrixes (collagen gels and porous collagen sponges). Differentiation of ES cells in these 3D systems was different from that in monolayers. ES cells differentiated in collagen matrixes into neural, epithelial, and endothelial lineages. The abilities of ES cells to form various structures in two chemically similar but topologically different matrixes were different. In particular, in collagen gels ES cells formed gland-like circular structures, whereas in collagen sponges ES cells were scattered through the matrix or formed aggregates. Soluble factors produced by feeder cells or added to the culture medium facilitated ES cell differentiation into particular lineages. Coculture with fibroblasts in collagen gel facilitated ES cell differentiation into cells of a neural lineage expressing nestin, neural cell adhesion molecule, and class III beta-tubulin. In collagen sponges, keratinocytes facilitated ES cell differentiation into cells of an endothelial lineage expressing factor VIII. Exogenous granulocyte-macrophage colony-stimulating factor further enhanced endothelial differentiation. Thus, both soluble factors and the type of extracellular matrix seem to be critical in directing differentiation of ES cells and the formation of tissue-like structures. Three-dimensional culture systems are a valuable tool for studying the mechanisms of these phenomena. PMID:12743323

  11. Multilineage differentiation of rhesus monkey embryonic stem cells in three-dimensional culture systems

    NASA Technical Reports Server (NTRS)

    Chen, Silvia S.; Revoltella, Roberto P.; Papini, Sandra; Michelini, Monica; Fitzgerald, Wendy; Zimmerberg, Joshua; Margolis, Leonid

    2003-01-01

    In the course of normal embryogenesis, embryonic stem (ES) cells differentiate along different lineages in the context of complex three-dimensional (3D) tissue structures. In order to study this phenomenon in vitro under controlled conditions, 3D culture systems are necessary. Here, we studied in vitro differentiation of rhesus monkey ES cells in 3D collagen matrixes (collagen gels and porous collagen sponges). Differentiation of ES cells in these 3D systems was different from that in monolayers. ES cells differentiated in collagen matrixes into neural, epithelial, and endothelial lineages. The abilities of ES cells to form various structures in two chemically similar but topologically different matrixes were different. In particular, in collagen gels ES cells formed gland-like circular structures, whereas in collagen sponges ES cells were scattered through the matrix or formed aggregates. Soluble factors produced by feeder cells or added to the culture medium facilitated ES cell differentiation into particular lineages. Coculture with fibroblasts in collagen gel facilitated ES cell differentiation into cells of a neural lineage expressing nestin, neural cell adhesion molecule, and class III beta-tubulin. In collagen sponges, keratinocytes facilitated ES cell differentiation into cells of an endothelial lineage expressing factor VIII. Exogenous granulocyte-macrophage colony-stimulating factor further enhanced endothelial differentiation. Thus, both soluble factors and the type of extracellular matrix seem to be critical in directing differentiation of ES cells and the formation of tissue-like structures. Three-dimensional culture systems are a valuable tool for studying the mechanisms of these phenomena.

  12. An immune-inspired swarm aggregation algorithm for self-healing swarm robotic systems.

    PubMed

    Timmis, J; Ismail, A R; Bjerknes, J D; Winfield, A F T

    2016-08-01

    Swarm robotics is concerned with the decentralised coordination of multiple robots having only limited communication and interaction abilities. Although fault tolerance and robustness to individual robot failures have often been used to justify the use of swarm robotic systems, recent studies have shown that swarm robotic systems are susceptible to certain types of failure. In this paper we propose an approach to self-healing swarm robotic systems and take inspiration from the process of granuloma formation, a process of containment and repair found in the immune system. We use a case study of a swarm performing team work where previous works have demonstrated that partially failed robots have the most detrimental effect on overall swarm behaviour. We have developed an immune inspired approach that permits the recovery from certain failure modes during operation of the swarm, overcoming issues that effect swarm behaviour associated with partially failed robots. PMID:27178784

  13. Short-Term Nitrogen Transformations Associated with Soil Aggregates and Microbial Community Composition in Three Different Tillage Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantifying soil nitrogen transformation processes associated with soil aggregates is noteworthy as microbial communities central to N cycle reside in the soil aggregates of different sizes. The objective of this investigation was to determine both the rates of ammonium production and consumption pr...

  14. INTEGRATED SAFETY MANAGEMENT SYSTEM SAFETY CULTURE IMPROVEMENT INITIATIVE

    SciTech Connect

    MCDONALD JA JR

    2009-01-16

    In 2007, the Department of Energy (DOE) identified safety culture as one of their top Integrated Safety Management System (ISMS) related priorities. A team was formed to address this issue. The team identified a consensus set of safety culture principles, along with implementation practices that could be used by DOE, NNSA, and their contractors. Documented improvement tools were identified and communicated to contractors participating in a year long pilot project. After a year, lessons learned will be collected and a path forward determined. The goal of this effort was to achieve improved safety and mission performance through ISMS continuous improvement. The focus of ISMS improvement was safety culture improvement building on operating experience from similar industries such as the domestic and international commercial nuclear and chemical industry.

  15. Investigation of work parameters of SI engine dedicated to energetics aggregates with pneumatic injection system

    NASA Astrophysics Data System (ADS)

    Marek, W.; Śliwiński, K.

    2016-09-01

    The article presents the possibilities of alternative fuel combustion in the engine four- stroke spark ignition engines. Power of the motor was carried out pneumatic fuel injection system using a hot gas developed by Prof. Stanislaw Jarnuszkiewicz. Presented made the position of the measuring system with the power and results. The engine experimental at the time of the study was powered by a blend of alcohol and gasoline. The main aim of the study was the question of control fuel dosage, taking into account the energy needs of forcing the engine load. During the tests carried load characteristics control the motor using the power control quality. Another issue was the elimination of penetration of fuel to the engine lubrication system, a problem occurred in the initial study on the issue of the pneumatic fuel injection using the hot exhaust gases. In summary we present the findings of this phase of the study.

  16. Slice Culture Modeling of Central Nervous System (CNS) Viral Infection

    PubMed Central

    Dionne, Kalen R.; Tyler, Kenneth L.

    2016-01-01

    The complexity of the central nervous system (CNS) is not recapitulated in cell culture models. Thin slicing and subsequent culture of CNS tissue has become a valued means to study neuronal and glial biology within the context of the physiologically relevant tissue milieu. Modern membrane-interface slice culturing methodology allows straightforward access to both CNS tissue and feeding medium, enabling experimental manipulations and analyses that would otherwise be impossible in vivo. CNS slices can be successfully maintained in culture for up to several weeks for investigation of evolving pathology and long-term intervention in models of chronic neurologic disease. Herein, membrane-interface slice culture models for studying viral encephalitis and myelitis are detailed, with emphasis on the use of these models for investigation of pathogenesis and evaluation of novel treatment strategies. We describe techniques to (1) generate brain and spinal cord slices from rodent donors, (2) virally infect slices, (3) monitor viral replication, (4) assess virally induced injury/apoptosis, (5) characterize “CNS-specific” cytokine production, and (6) treat slices with cytokines/pharmaceuticals. Although our focus is on CNS viral infection, we anticipate that the described methods can be adapted to address a wide range of investigations within the fields of neuropathology, neuroimmunology, and neuropharmacology. PMID:23975824

  17. Information Management Platform for Data Analytics and Aggregation (IMPALA) System Design Document

    NASA Technical Reports Server (NTRS)

    Carnell, Andrew; Akinyelu, Akinyele

    2016-01-01

    The System Design document tracks the design activities that are performed to guide the integration, installation, verification, and acceptance testing of the IMPALA Platform. The inputs to the design document are derived from the activities recorded in Tasks 1 through 6 of the Statement of Work (SOW), with the proposed technical solution being the completion of Phase 1-A. With the documentation of the architecture of the IMPALA Platform and the installation steps taken, the SDD will be a living document, capturing the details about capability enhancements and system improvements to the IMPALA Platform to provide users in development of accurate and precise analytical models. The IMPALA Platform infrastructure team, data architecture team, system integration team, security management team, project manager, NASA data scientists and users are the intended audience of this document. The IMPALA Platform is an assembly of commercial-off-the-shelf (COTS) products installed on an Apache-Hadoop platform. User interface details for the COTS products will be sourced from the COTS tools vendor documentation. The SDD is a focused explanation of the inputs, design steps, and projected outcomes of every design activity for the IMPALA Platform through installation and validation.

  18. Culture and the Immune System: Cultural Consonance in Social Support and C-reactive Protein in Urban Brazil.

    PubMed

    Dressler, William W; Balieiro, Mauro C; Ribeiro, Rosane P; Dos Santos, José Ernesto

    2016-06-01

    In this article, we examine the distribution of a marker of immune system stimulation-C-reactive protein-in urban Brazil. Social relationships are associated with immunostimulation, and we argue that cultural dimensions of social support, assessed by cultural consonance, are important in this process. Cultural consonance is the degree to which individuals, in their own beliefs and behaviors, approximate shared cultural models. A measure of cultural consonance in social support, based on a cultural consensus analysis regarding sources and patterns of social support in Brazil, was developed. In a survey of 258 persons, the association of cultural consonance in social support and C-reactive protein was examined, controlling for age, sex, body mass index, low-density lipoprotein cholesterol, depressive symptoms, and a social network index. Lower cultural consonance in social support was associated with higher C-reactive protein. Implications of these results for future research are discussed.

  19. Gender and cultural issues in psychiatric nosological classification systems.

    PubMed

    van de Water, Tanya; Suliman, Sharain; Seedat, Soraya

    2016-08-01

    Much has changed since the two dominant mental health nosological systems, the International Classification of Diseases (ICD) and the Diagnostic and Statistical Manual of Mental Disorders (DSM), were first published in 1900 and 1952, respectively. Despite numerous modifications to stay up to date with scientific and cultural changes (eg, exclusion of homosexuality as a disorder) and to improve the cultural sensitivity of psychiatric diagnoses, the ICD and DSM have only recently renewed attempts at harmonization. Previous nosological iterations demonstrate the oscillation in the importance placed on the biological focus, highlighting the tension between a gender- and culture-free nosology (solely biological) and a contextually relevant understanding of mental illness. In light of the release of the DSM 5, future nosological systems, such as the ICD 11, scheduled for release in 2017, and the Research Development Criteria (RDoC), can learn from history and apply critiques. This article aims to critically consider gender and culture in previous editions of the ICD and DSM to inform forthcoming classifications.

  20. Gender and cultural issues in psychiatric nosological classification systems.

    PubMed

    van de Water, Tanya; Suliman, Sharain; Seedat, Soraya

    2016-08-01

    Much has changed since the two dominant mental health nosological systems, the International Classification of Diseases (ICD) and the Diagnostic and Statistical Manual of Mental Disorders (DSM), were first published in 1900 and 1952, respectively. Despite numerous modifications to stay up to date with scientific and cultural changes (eg, exclusion of homosexuality as a disorder) and to improve the cultural sensitivity of psychiatric diagnoses, the ICD and DSM have only recently renewed attempts at harmonization. Previous nosological iterations demonstrate the oscillation in the importance placed on the biological focus, highlighting the tension between a gender- and culture-free nosology (solely biological) and a contextually relevant understanding of mental illness. In light of the release of the DSM 5, future nosological systems, such as the ICD 11, scheduled for release in 2017, and the Research Development Criteria (RDoC), can learn from history and apply critiques. This article aims to critically consider gender and culture in previous editions of the ICD and DSM to inform forthcoming classifications. PMID:27133577

  1. Cellulase production by a solid state culture system

    SciTech Connect

    Kim, J.H.; Hosobuchi, M.; Kishimoto, M.; Seki, T.; Yoshida, T.; Taguchi, H.; Ryu, D.D.Y.

    1985-10-01

    Production of cellulase using solid culture systems of Trichoderma reesei QM9414 and Sporotrichum cellulophilum on wheat bran was studied. By using moisture-controlled solid culture equipment, the effect of water content of wheat bran on cell growth and cellulase production was investigated. Cellular biomass grown on solid substrate was estimated by measuring oxygen consumption rate and glucosamine content the cells. These parameters were shown to have a good linear correlation with the specific growth rate. This reliable method of estimating the cell growth rate enabled us to simulate the enzyme production in a solid culture system by means of multiple linear regression analysis which takes into account of the water content, cell mass, and the oxygen consumption rate as variables. The cell growth and cellulase production were maximized at different water content of the medium. A high water content, 57% for T. reesei and 70% for S. cellulophilum, favored mycelial growth, while the maximum cellulase activity was obtained at a lower water content such as 50% for both fungi. It was observed that cellulase production by T. reesei depended on the culture conditions that support the optimal growth rate for the maximum enzyme production. 14 references.

  2. Three-dimensional printed polymeric system to encapsulate human mesenchymal stem cells differentiated into islet-like insulin-producing aggregates for diabetes treatment.

    PubMed

    Sabek, Omaima M; Farina, Marco; Fraga, Daniel W; Afshar, Solmaz; Ballerini, Andrea; Filgueira, Carly S; Thekkedath, Usha R; Grattoni, Alessandro; Gaber, A Osama

    2016-01-01

    Diabetes is one of the most prevalent, costly, and debilitating diseases in the world. Pancreas and islet transplants have shown success in re-establishing glucose control and reversing diabetic complications. However, both are limited by donor availability, need for continuous immunosuppression, loss of transplanted tissue due to dispersion, and lack of vascularization. To overcome the limitations of poor islet availability, here, we investigate the potential of bone marrow-derived mesenchymal stem cells differentiated into islet-like insulin-producing aggregates. Islet-like insulin-producing aggregates, characterized by gene expression, are shown to be similar to pancreatic islets and display positive immunostaining for insulin and glucagon. To address the limits of current encapsulation systems, we developed a novel three-dimensional printed, scalable, and potentially refillable polymeric construct (nanogland) to support islet-like insulin-producing aggregates' survival and function in the host body. In vitro studies showed that encapsulated islet-like insulin-producing aggregates maintained viability and function, producing steady levels of insulin for at least 4 weeks. Nanogland-islet-like insulin-producing aggregate technology here investigated as a proof of concept holds potential as an effective and innovative approach for diabetes cell therapy.

  3. Information support systems for cultural heritage protection against flooding

    NASA Astrophysics Data System (ADS)

    Nedvedova, K.; Pergl, R.

    2015-08-01

    The goal of this paper is to present use of different kind of software applications to create complex support system for protection of cultural heritage against flooding. The project is very complex and it tries to cover the whole area of the problem from prevention to liquidation of aftermath effects. We used GIS for mapping the risk areas, ontology systems for vulnerability assessment application and the BORM method (Business Object Relation Modelling) for flood protection system planning guide. Those modern technologies helped us to gather a lot of information in one place and provide the knowledge to the broad audience.

  4. Microfluidic cell culture system with on-chip hypoxic conditioning.

    PubMed

    Takano, Atsushi; Tanaka, Masato; Futai, Nobuyuki

    2013-01-01

    We have demonstrated a portable microfluidic cell culture system with multi-gas (CO2 and O2) incubation which we can cultivate under hypoxia without bulky peripheral apparatus such as gas tanks, regulators, and flow controllers. The system contains a chip of 26 mm × 48 mm which is capable to diffuse CO2 and absorb O2 through a gas-permeable wall of nested media reservoir. The media was water-jacketed with aqueous solution containing 0.8 M sodium bicarbonate as CO2 supply and 1 M sodium ascorbate as oxygen scavenger. The partial CO2 pressure (pCO2) in media reservoir stabilized at least 10.2% ± 0.11% for at least 72 hours. The partial O2 pressure (pO2) in the media reservoir decreased to 4.2%. Portable on-chip hypoxic culture of SV40-T2 cells for 72 h was also demonstrated. PMID:24110727

  5. Organisational culture matters for system integration in health care.

    PubMed

    Munir, Samina K; Kay, Stephen

    2003-01-01

    This paper illustrates the importance of organisational culture for Clinical Information Systems (CIS) integration. The study is based on data collected in intensive care units in the UK and Denmark. Data were collected using qualitative methods, i.e., observations, interviews and shadowing of health care providers, together with a questionnaire at each site. The data are analysed to extract salient variables for CIS integration, and it is shown that these variables can be separated into two categories that describe the 'Actual Usefulness' of the system and the 'Organisational Culture'. This model is then extended to show that CIS integration directly affects the work processes of the organisation, forming an iterative process of change as a CIS is introduced and integrated. PMID:14728220

  6. Multiplying steady-state culture in multi-reactor system.

    PubMed

    Erm, Sten; Adamberg, Kaarel; Vilu, Raivo

    2014-11-01

    Cultivation of microorganisms in batch experiments is fast and economical but the conditions therein change constantly, rendering quantitative data interpretation difficult. By using chemostat with controlled environmental conditions the physiological state of microorganisms is fixed; however, the unavoidable stabilization phase makes continuous methods resource consuming. Material can be spared by using micro scale devices, which however have limited analysis and process control capabilities. Described herein are a method and a system combining the high throughput of batch with the controlled environment of continuous cultivations. Microorganisms were prepared in one bioreactor followed by culture distribution into a network of bioreactors and continuation of independent steady state experiments therein. Accelerostat cultivation with statistical analysis of growth parameters demonstrated non-compromised physiological state following distribution, thus the method effectively multiplied steady state culture of microorganisms. The theoretical efficiency of the system was evaluated in inhibitory compound analysis using repeated chemostat to chemostat transfers.

  7. Embryo Aggregation in Pig Improves Cloning Efficiency and Embryo Quality.

    PubMed

    Buemo, Carla Paola; Gambini, Andrés; Moro, Lucia Natalia; Hiriart, María Inés; Fernández-Martín, Rafael; Collas, Philippe; Salamone, Daniel Felipe

    2016-01-01

    In this study, we analyzed the effects of the cloned embryo aggregation on in vitro embryo development and embryo quality by measuring blastocyst diameter and cell number, DNA fragmentation levels and the expression of genes associated with pluripotency, apoptosis, trophoblast and DNA methylation in the porcine. Zona-free reconstructed cloned embryos were cultured in the well of the well system, placing one (1x non aggregated group) or three (3x group) embryos per microwell. Our results showed that aggregation of three embryos increased blastocyst formation rate and blastocyst diameter of cloned pig embryos. DNA fragmentation levels in 3x aggregated cloned blastocysts were significantly decreased compared to 1x blastocysts. Levels of Oct4, Klf4, Igf2, Bax and Dnmt 1 transcripts were significantly higher in aggregated embryos, whereas Nanog levels were not affected. Transcripts of Cdx2 and Bcl-xl were essentially non-detectable. Our study suggests that embryo aggregation in the porcine may be beneficial for cloned embryo development and embryo quality, through a reduction in apoptotic levels and an improvement in cell reprogramming.

  8. Embryo Aggregation in Pig Improves Cloning Efficiency and Embryo Quality

    PubMed Central

    Buemo, Carla Paola; Gambini, Andrés; Moro, Lucia Natalia; Hiriart, María Inés; Fernández-Martín, Rafael; Collas, Philippe; Salamone, Daniel Felipe

    2016-01-01

    In this study, we analyzed the effects of the cloned embryo aggregation on in vitro embryo development and embryo quality by measuring blastocyst diameter and cell number, DNA fragmentation levels and the expression of genes associated with pluripotency, apoptosis, trophoblast and DNA methylation in the porcine. Zona-free reconstructed cloned embryos were cultured in the well of the well system, placing one (1x non aggregated group) or three (3x group) embryos per microwell. Our results showed that aggregation of three embryos increased blastocyst formation rate and blastocyst diameter of cloned pig embryos. DNA fragmentation levels in 3x aggregated cloned blastocysts were significantly decreased compared to 1x blastocysts. Levels of Oct4, Klf4, Igf2, Bax and Dnmt 1 transcripts were significantly higher in aggregated embryos, whereas Nanog levels were not affected. Transcripts of Cdx2 and Bcl-xl were essentially non-detectable. Our study suggests that embryo aggregation in the porcine may be beneficial for cloned embryo development and embryo quality, through a reduction in apoptotic levels and an improvement in cell reprogramming. PMID:26894831

  9. Embryo Aggregation in Pig Improves Cloning Efficiency and Embryo Quality.

    PubMed

    Buemo, Carla Paola; Gambini, Andrés; Moro, Lucia Natalia; Hiriart, María Inés; Fernández-Martín, Rafael; Collas, Philippe; Salamone, Daniel Felipe

    2016-01-01

    In this study, we analyzed the effects of the cloned embryo aggregation on in vitro embryo development and embryo quality by measuring blastocyst diameter and cell number, DNA fragmentation levels and the expression of genes associated with pluripotency, apoptosis, trophoblast and DNA methylation in the porcine. Zona-free reconstructed cloned embryos were cultured in the well of the well system, placing one (1x non aggregated group) or three (3x group) embryos per microwell. Our results showed that aggregation of three embryos increased blastocyst formation rate and blastocyst diameter of cloned pig embryos. DNA fragmentation levels in 3x aggregated cloned blastocysts were significantly decreased compared to 1x blastocysts. Levels of Oct4, Klf4, Igf2, Bax and Dnmt 1 transcripts were significantly higher in aggregated embryos, whereas Nanog levels were not affected. Transcripts of Cdx2 and Bcl-xl were essentially non-detectable. Our study suggests that embryo aggregation in the porcine may be beneficial for cloned embryo development and embryo quality, through a reduction in apoptotic levels and an improvement in cell reprogramming. PMID:26894831

  10. Shear Bond Strength of Calcium Enriched Mixture Cement and Mineral Trioxide Aggregate to Composite Resin with Two Different Adhesive Systems

    PubMed Central

    Savadi Oskoee, Siavash; Bahari, Mahmoud; Kimyai, Soodabeh; Motahhari, Paria; Eghbal, Mohammad Jafar; Asgary, Saeed

    2014-01-01

    Objective: Immediate restoration after vital pulp therapy is essential in order to create and maintain effective coronal seal. Purpose of Study: The aim of this study was to evaluate the shear bond strength of recently used pulp capping materials: white mineral trioxide aggregate (MTA), and calcium enriched mixture cement (CEM) to composite resin with the use of etch-and-rinse and self-etch adhesive systems and compare them with the bond strength of commonly used resin modified glass ionomer (RMGI) cement. Materials and Methods: Forty specimens from each test material were fabricated, measuring 4 mm in diameter and 2 mm in depth. The specimens of each material were divided into 2 groups of 20 specimens according to the adhesive system (Single Bond vs. Clearfil SE Bond) used for bonding of resin composite. The shear bond strength values were measured at a crosshead speed of 1.0 mm/min and fractured surfaces were examined. Data were analyzed using two-way ANOVA and a post hoc Tukey’s test (P<0.05). Results: Analysis of data showed a significantly higher bond strength for RMGI compared to MTA and CEM (P<0.001); however, no significant differences were observed in the bond strength values of MTA and CEM (P=0.9). Furthermore, there were no significant differences in relation to the type of the adhesive system irrespective of the type of the material used (P=0.95) All the failures were of cohesive type in RMGI, MTA and CEM. Conclusion: Bond strength of RMGI cement to composite resin was higher than that of MTA or CEM cement irrespective of the type of the adhesive system. PMID:25628696

  11. An Ex vivo Culture System to Study Thyroid Development

    PubMed Central

    Delmarcelle, Anne-Sophie; Villacorte, Mylah

    2014-01-01

    The thyroid is a bilobated endocrine gland localized at the base of the neck, producing the thyroid hormones T3, T4, and calcitonin. T3 and T4 are produced by differentiated thyrocytes, organized in closed spheres called follicles, while calcitonin is synthesized by C-cells, interspersed in between the follicles and a dense network of blood capillaries. Although adult thyroid architecture and functions have been extensively described and studied, the formation of the “angio-follicular” units, the distribution of C-cells in the parenchyma and the paracrine communications between epithelial and endothelial cells is far from being understood. This method describes the sequential steps of mouse embryonic thyroid anlagen dissection and its culture on semiporous filters or on microscopy plastic slides. Within a period of four days, this culture system faithfully recapitulates in vivo thyroid development. Indeed, (i) bilobation of the organ occurs (for e12.5 explants), (ii) thyrocytes precursors organize into follicles and polarize, (iii) thyrocytes and C-cells differentiate, and (iv) endothelial cells present in the microdissected tissue proliferate, migrate into the thyroid lobes, and closely associate with the epithelial cells, as they do in vivo. Thyroid tissues can be obtained from wild type, knockout or fluorescent transgenic embryos. Moreover, explants culture can be manipulated by addition of inhibitors, blocking antibodies, growth factors, or even cells or conditioned medium. Ex vivo development can be analyzed in real-time, or at any time of the culture by immunostaining and RT-qPCR. In conclusion, thyroid explant culture combined with downstream whole-mount or on sections imaging and gene expression profiling provides a powerful system for manipulating and studying morphogenetic and differentiation events of thyroid organogenesis. PMID:24961920

  12. Mammalian ribosomal and chaperone protein RPS3A counteracts α-synuclein aggregation and toxicity in a yeast model system.

    PubMed

    De Graeve, Stijn; Marinelli, Sarah; Stolz, Frank; Hendrix, Jelle; Vandamme, Jurgen; Engelborghs, Yves; Van Dijck, Patrick; Thevelein, Johan M

    2013-11-01

    Accumulation of aggregated forms of αSyn (α-synuclein) into Lewy bodies is a known hallmark associated with neuronal cell death in Parkinson's disease. When expressed in the yeast Saccharomyces cerevisiae, αSyn interacts with the plasma membrane, forms inclusions and causes a concentration-dependent growth defect. We have used a yeast mutant, cog6Δ, which is particularly sensitive to moderate αSyn expression, for screening a mouse brain-specific cDNA library in order to identify mammalian proteins that counteract αSyn toxicity. The mouse ribosomal and chaperone protein RPS3A was identified as a suppressor of αSyn [WT (wild-type) and A53T] toxicity in yeast. We demonstrated that the 50 N-terminal amino acids are essential for this function. The yeast homologues of RPS3A were not effective in suppressing the αSyn-induced growth defect, illustrating the potential of our screening system to identify modifiers that would be missed using yeast gene overexpression as the first screening step. Co-expression of mouse RPS3A delayed the formation of αSyn-GFP inclusions in the yeast cells. The results of the present study suggest that the recently identified extraribosomal chaperonin function of RPS3A also acts on the neurodegeneration-related protein αSyn and reveal a new avenue for identifying promising candidate mammalian proteins involved in αSyn functioning.

  13. Endothelin-1 release from cultured endothelial cells induced by sera from patients with systemic lupus erythematosus.

    PubMed Central

    Yoshio, T; Masuyama, J; Mimori, A; Takeda, A; Minota, S; Kano, S

    1995-01-01

    OBJECTIVES--To clarify the pathophysiological role of endothelin-1 (ET-1) in the vascular injury associated with systemic lupus erythematosus (SLE) by investigating the effect of sera from patients with SLE on ET-1 release from cultured human umbilical vein endothelial cells. METHODS--Confluent monolayers of cultured human umbilical vein endothelial cells were incubated with serum samples (diluted 1:10) from 25 patients with SLE and 16 normal controls for two hours at 37 degrees C and ET-1 concentration in the culture supernatant was measured by enzyme immunoassay. RESULTS--The mean release of ET-1 from endothelial cells in the presence of serum from SLE patients was greater than in the presence of serum from normal controls (p < 0.005). ET-1 release from endothelial cells significantly correlated with the titre of IgM anti-endothelial cell antibodies (IgM-AECA) and immune complex concentration in sera from SLE patients (p < 0.05 and p < 0.01, respectively). After gel chromatography of the serum from an SLE patient, those fractions containing IgM-AECA or immune complex were shown to stimulate ET-1 release from endothelial cells. Heat aggregated IgG also stimulated ET-1 release from endothelial cells in a concentration dependent manner. CONCLUSIONS--IgM-AECA and immune complexes may stimulate ET-1 release from endothelial cells and ET-1 may play an important role in the initiation and development of vascular injury, such as pulmonary hypertension and lupus nephritis, in SLE. PMID:7794041

  14. A mobile system for a comprehensive online-characterization of nanoparticle aggregates based on wide-angle light scattering and laser-induced incandescence

    NASA Astrophysics Data System (ADS)

    Huber, Franz J. T.; Altenhoff, Michael; Will, Stefan

    2016-05-01

    A mobile demonstrator for the comprehensive online-characterization of gas-borne nanoparticle aggregates is presented. Two optical measurement techniques are combined, both utilizing a pulsed Nd:YAG laser as light source. Aggregate size and fractal dimension are measured by Wide-Angle Light Scattering (WALS). An ellipsoidal mirror images elastically scattered light from scattering angles between 10° and 165° onto a CCD-camera chip resulting in an almost complete scattering diagram with high angular resolution. Primary particle size and volume fraction are measured by time-resolved Laser-Induced Incandescence (TiRe-LII). Here, particles are heated up to about 3000 K by the short laser pulse, the enhanced thermal radiation signal is detected with gated photomultiplier tubes. Analysis of the signal decay time and maximum LII-signal allows for the determination of primary particle diameter and volume fraction. The performance of the system is demonstrated by combined measurements on soot nanoparticle aggregates from a soot aerosol generator. Particle and aggregate sizes are varied by using different equivalence ratios of the combustion in the generator. Soot volume fraction can be adjusted by different levels of dilution with air. Online-measurements were carried out demonstrating the favorable performance of the system and the potential for industrial applications such as process control and product development. The particle properties obtained are confirmed through transmission electron microscopy analysis on representative samples.

  15. A mobile system for a comprehensive online-characterization of nanoparticle aggregates based on wide-angle light scattering and laser-induced incandescence.

    PubMed

    Huber, Franz J T; Altenhoff, Michael; Will, Stefan

    2016-05-01

    A mobile demonstrator for the comprehensive online-characterization of gas-borne nanoparticle aggregates is presented. Two optical measurement techniques are combined, both utilizing a pulsed Nd:YAG laser as light source. Aggregate size and fractal dimension are measured by Wide-Angle Light Scattering (WALS). An ellipsoidal mirror images elastically scattered light from scattering angles between 10° and 165° onto a CCD-camera chip resulting in an almost complete scattering diagram with high angular resolution. Primary particle size and volume fraction are measured by time-resolved Laser-Induced Incandescence (TiRe-LII). Here, particles are heated up to about 3000 K by the short laser pulse, the enhanced thermal radiation signal is detected with gated photomultiplier tubes. Analysis of the signal decay time and maximum LII-signal allows for the determination of primary particle diameter and volume fraction. The performance of the system is demonstrated by combined measurements on soot nanoparticle aggregates from a soot aerosol generator. Particle and aggregate sizes are varied by using different equivalence ratios of the combustion in the generator. Soot volume fraction can be adjusted by different levels of dilution with air. Online-measurements were carried out demonstrating the favorable performance of the system and the potential for industrial applications such as process control and product development. The particle properties obtained are confirmed through transmission electron microscopy analysis on representative samples. PMID:27250387

  16. Gill cell culture systems as models for aquatic environmental monitoring.

    PubMed

    Bury, Nic R; Schnell, Sabine; Hogstrand, Christer

    2014-03-01

    A vast number of chemicals require environmental safety assessments for market authorisation. To ensure acceptable water quality, effluents and natural waters are monitored for their potential harmful effects. Tests for market authorisation and environmental monitoring usually involve the use of large numbers of organisms and, for ethical, cost and logistic reasons, there is a drive to develop alternative methods that can predict toxicity to fish without the need to expose any animals. There is therefore a great interest in the potential to use cultured fish cells in chemical toxicity testing. This review summarises the advances made in the area and focuses in particular on a system of cultured fish gill cells grown into an epithelium that permits direct treatment with water samples.

  17. An Information System for European culture collections: the way forward.

    PubMed

    Casaregola, Serge; Vasilenko, Alexander; Romano, Paolo; Robert, Vincent; Ozerskaya, Svetlana; Kopf, Anna; Glöckner, Frank O; Smith, David

    2016-01-01

    Culture collections contain indispensable information about the microorganisms preserved in their repositories, such as taxonomical descriptions, origins, physiological and biochemical characteristics, bibliographic references, etc. However, information currently accessible in databases rarely adheres to common standard protocols. The resultant heterogeneity between culture collections, in terms of both content and format, notably hampers microorganism-based research and development (R&D). The optimized exploitation of these resources thus requires standardized, and simplified, access to the associated information. To this end, and in the interest of supporting R&D in the fields of agriculture, health and biotechnology, a pan-European distributed research infrastructure, MIRRI, including over 40 public culture collections and research institutes from 19 European countries, was established. A prime objective of MIRRI is to unite and provide universal access to the fragmented, and untapped, resources, information and expertise available in European public collections of microorganisms; a key component of which is to develop a dynamic Information System. For the first time, both culture collection curators as well as their users have been consulted and their feedback, concerning the needs and requirements for collection databases and data accessibility, utilised. Users primarily noted that databases were not interoperable, thus rendering a global search of multiple databases impossible. Unreliable or out-of-date and, in particular, non-homogenous, taxonomic information was also considered to be a major obstacle to searching microbial data efficiently. Moreover, complex searches are rarely possible in online databases thus limiting the extent of search queries. Curators also consider that overall harmonization-including Standard Operating Procedures, data structure, and software tools-is necessary to facilitate their work and to make high-quality data easily accessible

  18. An Information System for European culture collections: the way forward.

    PubMed

    Casaregola, Serge; Vasilenko, Alexander; Romano, Paolo; Robert, Vincent; Ozerskaya, Svetlana; Kopf, Anna; Glöckner, Frank O; Smith, David

    2016-01-01

    Culture collections contain indispensable information about the microorganisms preserved in their repositories, such as taxonomical descriptions, origins, physiological and biochemical characteristics, bibliographic references, etc. However, information currently accessible in databases rarely adheres to common standard protocols. The resultant heterogeneity between culture collections, in terms of both content and format, notably hampers microorganism-based research and development (R&D). The optimized exploitation of these resources thus requires standardized, and simplified, access to the associated information. To this end, and in the interest of supporting R&D in the fields of agriculture, health and biotechnology, a pan-European distributed research infrastructure, MIRRI, including over 40 public culture collections and research institutes from 19 European countries, was established. A prime objective of MIRRI is to unite and provide universal access to the fragmented, and untapped, resources, information and expertise available in European public collections of microorganisms; a key component of which is to develop a dynamic Information System. For the first time, both culture collection curators as well as their users have been consulted and their feedback, concerning the needs and requirements for collection databases and data accessibility, utilised. Users primarily noted that databases were not interoperable, thus rendering a global search of multiple databases impossible. Unreliable or out-of-date and, in particular, non-homogenous, taxonomic information was also considered to be a major obstacle to searching microbial data efficiently. Moreover, complex searches are rarely possible in online databases thus limiting the extent of search queries. Curators also consider that overall harmonization-including Standard Operating Procedures, data structure, and software tools-is necessary to facilitate their work and to make high-quality data easily accessible

  19. Culture.

    ERIC Educational Resources Information Center

    1997

    Twelve conference papers on cultural aspects of second language instruction include: "Towards True Multiculturalism: Ideas for Teachers" (Brian McVeigh); Comparing Cultures Through Critical Thinking: Development and Interpretations of Meaningful Observations" (Laurel D. Kamada); "Authority and Individualism in Japan and the USA" (Alisa Woodring);…

  20. A nanoscale bio-inspired light-harvesting system developed from self-assembled alkyl-functionalized metallochlorin nano-aggregates

    NASA Astrophysics Data System (ADS)

    Ocakoglu, Kasim; Joya, Khurram S.; Harputlu, Ersan; Tarnowska, Anna; Gryko, Daniel T.

    2014-07-01

    Self-assembled supramolecular organization of nano-structured biomimetic light-harvesting modules inside solid-state nano-templates can be exploited to develop excellent light-harvesting materials for artificial photosynthetic devices. We present here a hybrid light-harvesting system mimicking the chlorosomal structures of the natural photosynthetic system using synthetic zinc chlorin units (ZnChl-C6, ZnChl-C12 and ZnChl-C18) that are self-aggregated inside the anodic aluminum oxide (AAO) nano-channel membranes. AAO nano-templates were modified with a TiO2 matrix and functionalized with long hydrophobic chains to facilitate the formation of supramolecular Zn-chlorin aggregates. The transparent Zn-chlorin nano-aggregates inside the alkyl-TiO2 modified AAO nano-channels have a diameter of ~120 nm in a 60 μm length channel. UV-Vis studies and fluorescence emission spectra further confirm the formation of the supramolecular ZnChl aggregates from monomer molecules inside the alkyl-functionalized nano-channels. Our results prove that the novel and unique method can be used to produce efficient and stable light-harvesting assemblies for effective solar energy capture through transparent and stable nano-channel ceramic materials modified with bio-mimetic molecular self-assembled nano-aggregates.Self-assembled supramolecular organization of nano-structured biomimetic light-harvesting modules inside solid-state nano-templates can be exploited to develop excellent light-harvesting materials for artificial photosynthetic devices. We present here a hybrid light-harvesting system mimicking the chlorosomal structures of the natural photosynthetic system using synthetic zinc chlorin units (ZnChl-C6, ZnChl-C12 and ZnChl-C18) that are self-aggregated inside the anodic aluminum oxide (AAO) nano-channel membranes. AAO nano-templates were modified with a TiO2 matrix and functionalized with long hydrophobic chains to facilitate the formation of supramolecular Zn-chlorin aggregates. The

  1. Studies on the formation of hierarchical zeolite T aggregates with well-defined morphology in different template systems

    NASA Astrophysics Data System (ADS)

    Yin, Xiaoyan; Chu, Naibo; Lu, Xuewei; Li, Zhongfang; Guo, Hong

    2016-01-01

    In this paper, the disk-like and pumpkin-like hierarchical zeolite T aggregates consisted of primary nano-grains have been hydrothermally synthesized with and without the aid of the second template. The first template is used with tetramethylammonium hydroxide (TMAOH) and the second template is used with triethanolamine (TEA) or polyving akohol (PVA). A combination of characterization techniques, including XRD, SEM, TEM and N2 adsorption-desorption to examine the crystal crystallinity, morphology and surface properties of hierarchical zeolite T aggregates. In the single-template preparation process, the two-step varying-temperature treatment has been used to improve the meso-porosity of zeolite T aggregates. In the double-template preparation process, the amounts of PVA or TEA on the crystallinity, morphology and meso-porosity of zeolite T aggregates have been studied. It has been proved that the interstitial voids between the primary grains of aggregates are the origin of additional mesopores of samples. The micro- and meso-porosities of samples prepared with and without the second template have been contrasted in detail at last. In particular, the sample synthesized with the addition of PVA presents a hierarchical pore structure with the highest Sext value of 122 m2/g and Vmeso value of 0.255 cm3/g.

  2. 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.

  3. Role of streams in myxobacteria aggregate formation

    NASA Astrophysics Data System (ADS)

    Kiskowski, Maria A.; Jiang, Yi; Alber, Mark S.

    2004-10-01

    Cell contact, movement and directionality are important factors in biological development (morphogenesis), and myxobacteria are a model system for studying cell-cell interaction and cell organization preceding differentiation. When starved, thousands of myxobacteria cells align, stream and form aggregates which later develop into round, non-motile spores. Canonically, cell aggregation has been attributed to attractive chemotaxis, a long range interaction, but there is growing evidence that myxobacteria organization depends on contact-mediated cell-cell communication. We present a discrete stochastic model based on contact-mediated signaling that suggests an explanation for the initialization of early aggregates, aggregation dynamics and final aggregate distribution. Our model qualitatively reproduces the unique structures of myxobacteria aggregates and detailed stages which occur during myxobacteria aggregation: first, aggregates initialize in random positions and cells join aggregates by random walk; second, cells redistribute by moving within transient streams connecting aggregates. Streams play a critical role in final aggregate size distribution by redistributing cells among fewer, larger aggregates. The mechanism by which streams redistribute cells depends on aggregate sizes and is enhanced by noise. Our model predicts that with increased internal noise, more streams would form and streams would last longer. Simulation results suggest a series of new experiments.

  4. Three-dimensional printed polymeric system to encapsulate human mesenchymal stem cells differentiated into islet-like insulin-producing aggregates for diabetes treatment

    PubMed Central

    Sabek, Omaima M; Farina, Marco; Fraga, Daniel W; Afshar, Solmaz; Ballerini, Andrea; Filgueira, Carly S; Thekkedath, Usha R; Grattoni, Alessandro; Gaber, A Osama

    2016-01-01

    Diabetes is one of the most prevalent, costly, and debilitating diseases in the world. Pancreas and islet transplants have shown success in re-establishing glucose control and reversing diabetic complications. However, both are limited by donor availability, need for continuous immunosuppression, loss of transplanted tissue due to dispersion, and lack of vascularization. To overcome the limitations of poor islet availability, here, we investigate the potential of bone marrow–derived mesenchymal stem cells differentiated into islet-like insulin-producing aggregates. Islet-like insulin-producing aggregates, characterized by gene expression, are shown to be similar to pancreatic islets and display positive immunostaining for insulin and glucagon. To address the limits of current encapsulation systems, we developed a novel three-dimensional printed, scalable, and potentially refillable polymeric construct (nanogland) to support islet-like insulin-producing aggregates’ survival and function in the host body. In vitro studies showed that encapsulated islet-like insulin-producing aggregates maintained viability and function, producing steady levels of insulin for at least 4 weeks. Nanogland—islet-like insulin-producing aggregate technology here investigated as a proof of concept holds potential as an effective and innovative approach for diabetes cell therapy. PMID:27152147

  5. Tissue culture system for infection with human hepatitis delta virus.

    PubMed Central

    Sureau, C; Jacob, J R; Eichberg, J W; Lanford, R E

    1991-01-01

    An in vitro culture system was developed for assaying the infectivity of the human hepatitis delta virus (HDV). Hepatocytes were isolated from chimpanzee liver and grown in a serum-free medium. Cells were shown to be infectible by HDV and to remain susceptible to infection for at least 3 weeks in culture, as evidenced by the appearance of RNA species characteristic of HDV replication as early as 6 days postinfection. When repeated experiments were carried out on cells derived from an animal free of hepatitis B virus (HBV), HDV infection occurred in a consistent fashion but there was no indication of infection with the HBV that was present in the inoculum. Despite numerous attempts with different sources of HBV inocula free of HDV, there was no evidence that indicated susceptibility of these cells to HBV infection. This observation may indicate that HBV and HDV use different modes of entry into hepatocytes. When cells derived from an HBV-infected animal were exposed to HDV, synthesis and release of progeny HDV particles were obtained in addition to HBV replication and production of Dane particles. Although not infectible with HBV, primary cultures of chimpanzee hepatocytes are capable of supporting part of the life cycle of HBV and the entire life cycle of HDV. Images PMID:2041075

  6. Optimization of culture conditions for an efficient xeno-feeder free limbal cell culture system towards ocular surface regeneration.

    PubMed

    Varghese, Viji Mary; Prasad, Tilak; Kumary, T V

    2010-10-01

    Ex vivo expansion of limbal stem cells from a small biopsy and its subsequent transplantation is the golden choice of treatment for limbal stem cell deficiency. Use of murine 3T3 feeder layer is a prerequisite for this ex vivo expansion. There is an ever-increasing demand for feeder free cultures to avoid xenotoxicity and transmission of xeno-diseases to human system. This study was aimed to establish an efficient xeno-feeder free limbal culture system towards ocular surface regeneration. To study the effect of initial dispase treatment and culture system used, migratory distance of cells from explants was analyzed from phase contrast images using "interactive measurements" of Qwin software (Leica). Expression of p63 in different culture systems was studied by immunofluorescent staining, followed by quantitative confocal microscopy (Carl Zeiss). Results showed dispase treatment was not necessary for establishing limbal explant culture. A combination of Iscove's modified Dulbecco's medium and Panserin 801 resulted in formation of autofeeder layer with maintenance of progenitor characteristics, thus mimicking natural tissue architecture. Further analysis of this culture system showed that cells could be cultured till confluency. Immunofluorescent staining of ABCG2 revealed presence of stem cell marker in the confluent cell layer. Scanning Electron Micrographs demonstrated homogenous population of tightly packed cells in this culture system. Replacement of bovine serum with autologous serum did not affect morphology or growth of cells in this culture system. This study will be a major step in the development of xeno-feeder free epithelial equivalents towards ocular surface reconstruction. PMID:20196106

  7. The Cultural Erosion Metaphor and the Transcultural Impact of Media Systems.

    ERIC Educational Resources Information Center

    Varan, Duane

    1998-01-01

    Contributes to scholarship on the transcultural impact of media systems (and draws on media effects, political economy, and cultural studies research) by applying the soil erosion metaphor to transcultural impact of television. Discusses four processes associated with this model: cultural abrasion, cultural deflation, cultural deposition, and…

  8. Fine bubble mixing (FBM) culture of E. coli: a highly cost-effective middle scale-size culture system.

    PubMed

    Yasumitsu, Hidetaro; Tajima, Hitoshi; Isobe, Masaharu; Kutsuna, Sinsuke; Kawsar, Sarkar M A; Fujii, Yuki; Kanaly, Robert A; Ozeki, Yasuhiro; Yokota, Eriko

    2013-02-01

    A highly cost-effective and easy-to-assemble cultivation system suitable for middle scale-size culturing of bacterial cells is described. In the culture, from a flat-shaped air-stone with large surface area, fine bubbles are generated with a low-cost air pump available in an aquarium fish shop, and cell-agitation and oxygen supply are efficiently conducted by fine bubbles simultaneously. Growth properties of the cells and their saturation density are comparable to those in a conventional culture system. The expression of recombinant protein was revealed to be similar to conventional methods. The system does not require any expensive machines or equipments. In addition, all equipments except plastic flat-shaped airstone are reusable after sterilization. Due to the low cost, the ease to use and multiple cultivations at once, our system may enable to find better culture conditions, to scale-up with ease and to perform timesaving efficient protein production. PMID:22894161

  9. Culturally Competent School Leaders: The Individual and the System

    ERIC Educational Resources Information Center

    Hansuvadha, Nat; Slater, Charles L.

    2012-01-01

    Cultural competence is the knowledge, behaviors, and dispositions necessary to effectively interact with other cultural groups. Two case studies are presented which illustrate the cultural competence of administrators in urban settings. Theories are reviewed to investigate the themes of cultural competence that emerged from the professional…

  10. The Heparin-Induced Thrombocytopenia and Thrombosis Syndrome: Treatment with Intraarterial Urokinase and Systemic Platelet Aggregation Inhibitors

    SciTech Connect

    Murphy, Kenneth D.; McCrohan, Gerard; DeMarta, Deborah A.; Shirodkar, Nitin B.; Kwon, Oun J.; Chopra, Paramjit S.

    1996-03-15

    We report a case of the heparin-induced thrombocytopenia and thrombosis syndrome presenting with acute ischemia of a lower limb. The patient was successfully treated by withdrawal of heparin products, intraarterial urokinase, and platelet anti-aggregation therapy consisting of Dextran and aspirin.

  11. Lean management systems: creating a culture of continuous quality improvement.

    PubMed

    Clark, David M; Silvester, Kate; Knowles, Simon

    2013-08-01

    This is the first in a series of articles describing the application of Lean management systems to Laboratory Medicine. Lean is the term used to describe a principle-based continuous quality improvement (CQI) management system based on the Toyota production system (TPS) that has been evolving for over 70 years. Its origins go back much further and are heavily influenced by the work of W Edwards Deming and the scientific method that forms the basis of most quality management systems. Lean has two fundamental elements--a systematic approach to process improvement by removing waste in order to maximise value for the end-user of the service and a commitment to respect, challenge and develop the people who work within the service to create a culture of continuous improvement. Lean principles have been applied to a growing number of Healthcare systems throughout the world to improve the quality and cost-effectiveness of services for patients and a number of laboratories from all the pathology disciplines have used Lean to shorten turnaround times, improve quality (reduce errors) and improve productivity. Increasingly, models used to plan and implement large scale change in healthcare systems, including the National Health Service (NHS) change model, have evidence-based improvement methodologies (such as Lean CQI) as a core component. Consequently, a working knowledge of improvement methodology will be a core skill for Pathologists involved in leadership and management.

  12. A Novel Component Carrier Configuration and Switching Scheme for Real-Time Traffic in a Cognitive-Radio-Based Spectrum Aggregation System.

    PubMed

    Fu, Yunhai; Ma, Lin; Xu, Yubin

    2015-01-01

    In spectrum aggregation (SA), two or more component carriers (CCs) of different bandwidths in different bands can be aggregated to support a wider transmission bandwidth. The scheduling delay is the most important design constraint for the broadband wireless trunking (BWT) system, especially in the cognitive radio (CR) condition. The current resource scheduling schemes for spectrum aggregation become questionable and are not suitable for meeting the challenge of the delay requirement. Consequently, the authors propose a novel component carrier configuration and switching scheme for real-time traffic (RT-CCCS) to satisfy the delay requirement in the CR-based SA system. In this work, the authors consider a sensor-network-assisted CR network. The authors first introduce a resource scheduling structure for SA in the CR condition. Then the proposed scheme is analyzed in detail. Finally, simulations are carried out to verify the analysis on the proposed scheme. Simulation results prove that our proposed scheme can satisfy the delay requirement in the CR-based SA system. PMID:26393594

  13. A Novel Component Carrier Configuration and Switching Scheme for Real-Time Traffic in a Cognitive-Radio-Based Spectrum Aggregation System

    PubMed Central

    Fu, Yunhai; Ma, Lin; Xu, Yubin

    2015-01-01

    In spectrum aggregation (SA), two or more component carriers (CCs) of different bandwidths in different bands can be aggregated to support a wider transmission bandwidth. The scheduling delay is the most important design constraint for the broadband wireless trunking (BWT) system, especially in the cognitive radio (CR) condition. The current resource scheduling schemes for spectrum aggregation become questionable and are not suitable for meeting the challenge of the delay requirement. Consequently, the authors propose a novel component carrier configuration and switching scheme for real-time traffic (RT-CCCS) to satisfy the delay requirement in the CR-based SA system. In this work, the authors consider a sensor-network-assisted CR network. The authors first introduce a resource scheduling structure for SA in the CR condition. Then the proposed scheme is analyzed in detail. Finally, simulations are carried out to verify the analysis on the proposed scheme. Simulation results prove that our proposed scheme can satisfy the delay requirement in the CR-based SA system. PMID:26393594

  14. A Novel Component Carrier Configuration and Switching Scheme for Real-Time Traffic in a Cognitive-Radio-Based Spectrum Aggregation System.

    PubMed

    Fu, Yunhai; Ma, Lin; Xu, Yubin

    2015-09-17

    In spectrum aggregation (SA), two or more component carriers (CCs) of different bandwidths in different bands can be aggregated to support a wider transmission bandwidth. The scheduling delay is the most important design constraint for the broadband wireless trunking (BWT) system, especially in the cognitive radio (CR) condition. The current resource scheduling schemes for spectrum aggregation become questionable and are not suitable for meeting the challenge of the delay requirement. Consequently, the authors propose a novel component carrier configuration and switching scheme for real-time traffic (RT-CCCS) to satisfy the delay requirement in the CR-based SA system. In this work, the authors consider a sensor-network-assisted CR network. The authors first introduce a resource scheduling structure for SA in the CR condition. Then the proposed scheme is analyzed in detail. Finally, simulations are carried out to verify the analysis on the proposed scheme. Simulation results prove that our proposed scheme can satisfy the delay requirement in the CR-based SA system.

  15. The SAWO (Small And Well Organized) avatar teaches the importance of the aggregates on the soil system and how to determine their stability

    NASA Astrophysics Data System (ADS)

    Mataix-Solera, Jorge; Cerdà, Artemi; Jordán, Antonio; Úbeda, Xavier; Pereira, Paulo

    2015-04-01

    Soil structure is the key factor that determine the soil quality as control the organic matter turnnover, soil biology and soil erodibility (Cerdà, 1996; 1998; Wick et al., 2014; Gelaw, 2015). There is a need to understand better the factors and the processes that act on the soil aggregation and the dynamics of the soil aggregation, which will make easier to understand the soil system functioning (Jordán et al., 2011; Jordán et al., 2012; Pulido Moncada et al., 2013). Fire, mines, grazing and agricultura (Cerdà, 2000; Mataix Solera et al., 2011; Cerdà et al., 2012; Hallett et al., 2014; Lozano et al., 2013) determines how the soil structure is highly affected by the humankind. And this determines the sustainability of the land managements (García Orenes et al., 2012; K¨ropfl et al., 2013; Mekuria and Aynekulu, 2013; Taguas et al., 2013; Zhao et al., 2013). Aggregates are Small And Well Organized (SAWO) structures that allow the water to flow, the air fill the porous and the life to be diverse and abundant in the soil. The SAWO avatar will teach the importance of the functions and the services of the aggregates to students and other scientists, but also to any audience. This means that the experiments and the vocabulary to be used by SAWO will be very wide and rich. The Avatar SAWO will use different strategies and skills to teach the soil aggregation properties and characteristics. And also, how to measure. Easy to carry out experiments will be shown by SAWO to measure the aggregate stability in the field and in the laboratory, and the soil sampling in the field. The SAWO avatar will play a special attention to the impact of forest fires on aggregate stability changes and how to measure. The SAWO avatar will teach how to take samples in the field, how to transport and manage in the laboratory, and finally which measurements and test can be done to determine the aggregate stability. Acknowledgements To the "Ministerio de Economía and Competitividad" of

  16. Development of a bovine luteal cell in vitro culture system suitable for co-culture with early embryos.

    PubMed

    Batista, M; Torres, A; Diniz, P; Mateus, L; Lopes-da-Costa, L

    2012-10-01

    The cross talk between the corpus luteum (CL) and the early embryo, potentially relevant to pregnancy establishment, is difficult to evaluate in the in vivo bovine model. In vitro co-culture of bovine luteal cells and early embryos (days 2-8 post in vitro fertilization) may allow the deciphering of this poorly understood cross talk. However, early embryos and somatic cells require different in vitro culture conditions. The objective of this study was to develop a bovine luteal cell in vitro culture system suitable for co-culture with early embryos in order to evaluate their putative steroidogenic and prostanoid interactions. The corpora lutea of the different stages of the estrous cycle (early, mid, and late) were recovered postmortem and enriched luteal cell populations were obtained. In experiments 1 and 2, the effects of CL stage, culture medium (TCM, DMEM-F12, or SOF), serum concentration (5 or 10%), atmosphere oxygen tension (5 or 20%), and refreshment of the medium on the ability of luteal cells to produce progesterone (P(4)) were evaluated. The production of P(4) was significantly increased in early CL cultures, and luteal cells adapted well to simple media (SOF), low serum concentrations (5%), and oxygen tensions (5%). In experiment 3, previous luteal cell cryopreservation did not affect the production of P(4), PGF(2α), and PGE(2) compared to fresh cell cultures. This enables the use of pools of frozen-thawed cells to decrease the variation in cell function associated with primary cell cultures. In experiment 4, mineral oil overlaying culture wells resulted in a 50-fold decrease of the P(4) quantified in the medium, but had no effect on PGF(2α) and PGE(2) quantification. In conclusion, a luteal cell in vitro culture system suitable for the 5-d-long co-culture with early embryos was developed.

  17. Development of a bovine luteal cell in vitro culture system suitable for co-culture with early embryos.

    PubMed

    Batista, M; Torres, A; Diniz, P; Mateus, L; Lopes-da-Costa, L

    2012-10-01

    The cross talk between the corpus luteum (CL) and the early embryo, potentially relevant to pregnancy establishment, is difficult to evaluate in the in vivo bovine model. In vitro co-culture of bovine luteal cells and early embryos (days 2-8 post in vitro fertilization) may allow the deciphering of this poorly understood cross talk. However, early embryos and somatic cells require different in vitro culture conditions. The objective of this study was to develop a bovine luteal cell in vitro culture system suitable for co-culture with early embryos in order to evaluate their putative steroidogenic and prostanoid interactions. The corpora lutea of the different stages of the estrous cycle (early, mid, and late) were recovered postmortem and enriched luteal cell populations were obtained. In experiments 1 and 2, the effects of CL stage, culture medium (TCM, DMEM-F12, or SOF), serum concentration (5 or 10%), atmosphere oxygen tension (5 or 20%), and refreshment of the medium on the ability of luteal cells to produce progesterone (P(4)) were evaluated. The production of P(4) was significantly increased in early CL cultures, and luteal cells adapted well to simple media (SOF), low serum concentrations (5%), and oxygen tensions (5%). In experiment 3, previous luteal cell cryopreservation did not affect the production of P(4), PGF(2α), and PGE(2) compared to fresh cell cultures. This enables the use of pools of frozen-thawed cells to decrease the variation in cell function associated with primary cell cultures. In experiment 4, mineral oil overlaying culture wells resulted in a 50-fold decrease of the P(4) quantified in the medium, but had no effect on PGF(2α) and PGE(2) quantification. In conclusion, a luteal cell in vitro culture system suitable for the 5-d-long co-culture with early embryos was developed. PMID:23054443

  18. The Relationship between National Culture and the Usability of an E-Learning System

    ERIC Educational Resources Information Center

    Downey, Steve; Wentling, Rose Mary; Wentling, Tim; Wadsworth, Andrew

    2004-01-01

    This study sought to measure the relationship between national culture and the usability of an e-Learning system by using Hofstede's cultural dimensions and Nielson's usability attributes. The study revealed that high uncertainty avoidance cultures found the system more frustrating to use. The study also revealed that individuals from cultures…

  19. The SAWO (Small And Well Organized) avatar teaches the importance of the aggregates on the soil system and how to determine their stability

    NASA Astrophysics Data System (ADS)

    Mataix-Solera, Jorge; Cerdà, Artemi; Jordán, Antonio; Úbeda, Xavier; Pereira, Paulo

    2015-04-01

    Soil structure is the key factor that determine the soil quality as control the organic matter turnnover, soil biology and soil erodibility (Cerdà, 1996; 1998; Wick et al., 2014; Gelaw, 2015). There is a need to understand better the factors and the processes that act on the soil aggregation and the dynamics of the soil aggregation, which will make easier to understand the soil system functioning (Jordán et al., 2011; Jordán et al., 2012; Pulido Moncada et al., 2013). Fire, mines, grazing and agricultura (Cerdà, 2000; Mataix Solera et al., 2011; Cerdà et al., 2012; Hallett et al., 2014; Lozano et al., 2013) determines how the soil structure is highly affected by the humankind. And this determines the sustainability of the land managements (García Orenes et al., 2012; K¨ropfl et al., 2013; Mekuria and Aynekulu, 2013; Taguas et al., 2013; Zhao et al., 2013). Aggregates are Small And Well Organized (SAWO) structures that allow the water to flow, the air fill the porous and the life to be diverse and abundant in the soil. The SAWO avatar will teach the importance of the functions and the services of the aggregates to students and other scientists, but also to any audience. This means that the experiments and the vocabulary to be used by SAWO will be very wide and rich. The Avatar SAWO will use different strategies and skills to teach the soil aggregation properties and characteristics. And also, how to measure. Easy to carry out experiments will be shown by SAWO to measure the aggregate stability in the field and in the laboratory, and the soil sampling in the field. The SAWO avatar will play a special attention to the impact of forest fires on aggregate stability changes and how to measure. The SAWO avatar will teach how to take samples in the field, how to transport and manage in the laboratory, and finally which measurements and test can be done to determine the aggregate stability. Acknowledgements To the "Ministerio de Economía and Competitividad" of

  20. Cadmium and the reticuloendothelial system (RES). A specific defect in blood clearance of soluble aggregates of IgG by the liver in mice given cadmium.

    PubMed Central

    Knutson, D W; Vredevoe, D L; Aoki, K R; Hays, E J; Levy, L

    1980-01-01

    The ability of the reticuloendothelial system (RES) to bind and catabolize soluble stable heat aggregates of 125I-IgG (A-IgG) was studied in mice given oral cadmium. Cadmium caused a delay in the circulation clearance of A-IgG in intact animals. The defect was due to impaired liver uptake of A-IgG and correlated with increased liver cadmium. Subsequent catabolism of bound A-IgG by liver slices was not affected. The defect was specific in that clearance of aggregated human serum albumin and colloidal carbon was normal in cadmium mice; this suggests that cadmium may affect either Fc or complement receptors of Kupffer cells in liver. PMID:7419241

  1. A Neuronal Culture System to Detect Prion Synaptotoxicity

    PubMed Central

    Fang, Cheng; Imberdis, Thibaut; Garza, Maria Carmen; Wille, Holger; Harris, David A.

    2016-01-01

    Synaptic pathology is an early feature of prion as well as other neurodegenerative diseases. Although the self-templating process by which prions propagate is well established, the mechanisms by which prions cause synaptotoxicity are poorly understood, due largely to the absence of experimentally tractable cell culture models. Here, we report that exposure of cultured hippocampal neurons to PrPSc, the infectious isoform of the prion protein, results in rapid retraction of dendritic spines. This effect is entirely dependent on expression of the cellular prion protein, PrPC, by target neurons, and on the presence of a nine-amino acid, polybasic region at the N-terminus of the PrPC molecule. Both protease-resistant and protease-sensitive forms of PrPSc cause dendritic loss. This system provides new insights into the mechanisms responsible for prion neurotoxicity, and it provides a platform for characterizing different pathogenic forms of PrPSc and testing potential therapeutic agents. PMID:27227882

  2. Development and use of culture systems to modulate specific cell responses

    NASA Astrophysics Data System (ADS)

    Martin, Yves

    Culture surfaces that induce specific localized cell responses are required to achieve tissue-like cell growth in three-dimensional (3D) environments, as well as to develop more efficient cell-based diagnostic techniques, noticeably when working with fragile cells such as stem cells or platelets. As such, Chapter 1 of this thesis work is devoted to the review of 3D cell-material interactions in vitro and the corresponding existing culture systems available to achieve in vivo-like cell responses. More adequate 3D culture systems will need to be developed to mimic several characteristics of in vivo environments, including lowered non-specific cell-material interactions and localized biochemical signaling. The experimental work in this thesis is based on the hypothesis that well-studied and optimized surface treatments will be able to lower non-specific cell-material interactions and allow local chemical modification in order to achieve specific localized cell-material interactions for different applications. As such, in Chapter 2 and Chapter 3 of this thesis, surface treatments were developed using plasma polymerization and covalent immobilization of a low-fouling polymer (i.e., poly(ethylene glycol)) and characterized and optimized using a large number of techniques including atomic force microscopy, quartz crystal microbalance, surface plasmon resonance, x-ray photoelectron spectroscopy and fluorescence-based techniques. The main plasma polymerization parameter important for surface chemical content, specifically nitrogen to carbon content, was identified as being glow discharge power, while reaction time and power determined plasma film thickness. Moreover, plasma films were shown to be stable in aqueous environments. Covalently-bound poly(ethylene glycol) (PEG) layers physicochemical and mechanical properties are dependent on fabrication methods. Polymer concentration in solution is an important indicator of final layer properties, and use of a theta solvent

  3. Biochemical Study of Mixed Culture Prototype in a Closed Ecological System

    NASA Technical Reports Server (NTRS)

    Tischer, R. G.

    1960-01-01

    Since June 1, 1960, the date of initiation of this research project, efforts have been directed toward studying cultural and fermentation patterns and the methodology of pure culture isolation of prototype microorganisms to be employed in closed ecological systems.

  4. Mobile system for in-situ imaging of cultural objects

    NASA Astrophysics Data System (ADS)

    Zemlicka, J.; Jakubek, J.; Krejci, F.; Hradil, D.; Hradilova, J.; Mislerova, H.

    2012-01-01

    Non-invasive analytical techniques recently developed with the Timepix pixel detector have shown great potential for the inspection of objects of cultural heritage. We have developed new instrumentation and methodology for in-situ X-ray transmission radiography and X-ray fluorescence imaging and successfully tested and evaluated a mobile system for remote terrain tasks. The prototype portable imaging device comprises the radiation source tube and the spectral sensitive X-ray camera. Both components can be moreover mounted on independent motorized positioning systems allowing adaptation of irradiation geometry to the object shape. Both parts are placed onto a pair of universal portable holders (tripods). The detector is placed in a shielded box with exchangeable entrance window (beam filters and pinhole collimator). This adjustable setup allows performing in-situ measurements for both transmission and emission (XRF) radiography. The assembled system has been successfully tested in our laboratory with phantoms and real samples. The obtained and evaluated results are presented in this paper. Future work will include successive adaptation of the current system for real in-situ utilization and preparation of software allowing semi-automatic remote control of measurements.

  5. Organotypic slice co-culture systems to study axon regeneration in the dopaminergic system ex vivo.

    PubMed

    Heine, Claudia; Franke, Heike

    2014-01-01

    Organotypic slice co-cultures are suitable tools to study axonal regeneration and development (growth or regrowth) of different projection systems of the CNS under ex vivo conditions.In this chapter, we describe in detail the reconstruction of the mesocortical and nigrostriatal dopaminergic projection system culturing tissue slices from the ventral tegmental area/substantia nigra (VTA/SN) with the prefrontal cortex (PFC) or the striatum (STR). The protocol includes the detailed slice preparation and incubation. Moreover, different application possibilities of the ex vivo model are mentioned; as an example, the substance treatment procedure and biocytin tracing are described to reveal the effect of applied substances on fiber outgrowth. PMID:24838961

  6. [Molecular heterogeneity of proteoglycan aggregates of human hyalin cartilage in normal conditions and in systemic bone dysplasia].

    PubMed

    Feshchenko, S P; Krasnopol'skaia, K D; Rebrin, I A; Rudakov, S S

    1989-01-01

    Components of proteoglycan aggregates of human hyalin cartilage were studied under conditions of normal state and in some forms of osteochondrodysplasia. Extraction of uronic acids and protein from the tissue, amount of fractions and electrophoretic mobility of proteoglycan monomers, rations protein/glycosaminoglycans, keratan sulfate/chondroitin sulfate, a level and type of sulfatation as well as molecular mass of chondroitin sulfate, amino acid composition of rod protein, heterogeneity of binding proteins (concerning their isoelectric points and molecular masses) and immunoreactivity of protein moiety in proteoglycan aggregates were studied in rib cartilage, knee joint and ala ossis ilii. Structural parameters of proteoglycan aggregates proved to be dissimilar and depended on cartilage localization and age of the donors. Impairments in the rate of chondroitin sulfate sulfatation were detected in achondrogenesis of the II type and in diastrophic dysplasia; an extraction ability and amount of proteoglycan fractions, relative content of glycosaminoglycans and binding proteins were altered in some other forms of osteochondrodysplasias. Numerous biochemical markers of extracellular matrix deterioration were detected, which are typical for various morphofunctional alterations in hyalin cartilage--hyperproliferative reactions, tissue prematuration, persistence of the embryonal type of metabolism. PMID:2472707

  7. Simulation of J-aggregate microcavity photoluminescence

    NASA Astrophysics Data System (ADS)

    Michetti, Paolo; La Rocca, Giuseppe C.

    2008-05-01

    We have developed a model in order to account for the photoexcitation dynamics of J-aggregate films and strongly coupled J-aggregate microcavities. The J aggregates are described as a disordered Frenkel exciton system in which relaxation occurs due to the presence of a thermal bath of molecular vibrations. The correspondence between the photophysics in J-aggregate films and that in J-aggregate microcavities is obtained by introducing a model polariton wave function mixing cavity photon modes and J-aggregate super-radiant excitons. With the same description of the material properties, we have calculated both absorption and luminescence spectra for the J-aggregate film and the photoluminescence of strongly coupled organic microcavities. The model is able to account for the fast relaxation dynamics in organic microcavities following nonresonant pumping and explains the temperature dependence of the ratio between the upper polariton and the lower polariton luminescence.

  8. Competition of Invertebrates Mixed Culture in the Closed Aquatic System

    NASA Astrophysics Data System (ADS)

    Pisman, Tamara

    The study considers the experimental model of interactions between invertebrates (the cilates Paramecium caudatum, Paramecium bursaria and the rotifers Brachionis plicatilis) in the closed aquatic system. The infusoria P.caudatum can feed on yeast, bacteria and chlorella; in this experiment growth and reproduction were maintained by bacteria only. The P.bursaria - zoochlorella endosymbiosis is a natural model of a simple biotic cycle. P.bursaria consumes glucose and oxygen released by zoochlorella in the process of biosynthesis and releases nitrogenous compounds and carbon dioxide necessary for algal photosynthesis. The rotifers Br. plicatilis can consume algae, bacteria and detritus. Thus in experiment with the mixed culture of invertebrates they can use different food sources. However with any initial percentage of the invertebrates the end portion of P.bursaria reaches 90-99

  9. Effect of cysteine on lowering protein aggregation and subsequent hardening of whey protein isolate (WPI) protein bars in WPI/buffer model systems.

    PubMed

    Zhu, Dan; Labuza, Theodore P

    2010-07-14

    Whey protein isolate (WPI) bar hardening without and with cysteine (Cys) or N-ethylmaleimide (NEM) was investigated in model systems (WPI/buffer = 6:4, by weight, pH 6.8, a(w) approximately 0.97) in an accelerated shelf-life test (ASLT) at 45 degrees C over a period of up to 35 days. The formation of insoluble aggregates as determined by solubility and the structural rearrangement of WPI protein aggregates as observed by SEM were responsible for the WPI bars' hardening. As corroborated by electrophoresis analysis, both beta-lactoglobulin (beta-lg) and alpha-lactalbumin (alpha-la) were involved in the formation of aggregates via the thiol-disulfide interchange reaction and/or noncovalent interactions. The former force dominated the bar hardening at an earlier stage, whereas the latter force played a role for the long-term hardening. In comparison with the control bar without Cys, the thiol-disulfide interchange reaction was significantly reduced by Cys (WPI/Cys = 0.05), increased by Cys (WPI/Cys = 0.25), and inhibited by NEM (WPI/NEM = 2). Therefore, bar hardening was significantly delayed by Cys (WPI/Cys = 0.05) and NEM but accelerated by Cys (WPI/Cys = 0.25).

  10. Biogrid--a microfluidic device for large-scale enzyme-free dissociation of stem cell aggregates.

    PubMed

    Wallman, Lars; Åkesson, Elisabet; Ceric, Dario; Andersson, Per Henrik; Day, Kelly; Hovatta, Outi; Falci, Scott; Laurell, Thomas; Sundström, Erik

    2011-10-01

    Culturing stem cells as free-floating aggregates in suspension facilitates large-scale production of cells in closed systems, for clinical use. To comply with GMP standards, the use of substances such as proteolytic enzymes should be avoided. Instead of enzymatic dissociation, the growing cell aggregates may be mechanically cut at passage, but available methods are not compatible with large-scale cell production and hence translation into the clinic becomes a severe bottle-neck. We have developed the Biogrid device, which consists of an array of micrometerscale knife edges, micro-fabricated in silicon, and a manifold in which the microgrid is placed across the central fluid channel. By connecting one side of the Biogrid to a syringe or a pump and the other side to the cell culture, the culture medium with suspended cell aggregates can be aspirated, forcing the aggregates through the microgrid, and ejected back to the cell culture container. Large aggregates are thereby dissociated into smaller fragments while small aggregates pass through the microgrid unaffected. As proof-of-concept, we demonstrate that the Biogrid device can be successfully used for repeated passage of human neural stem/progenitor cells cultured as so-called neurospheres, as well as for passage of suspension cultures of human embryonic stem cells. We also show that human neural stem/progenitor cells tolerate transient pressure changes far exceeding those that will occur in a fluidic system incorporating the Biogrid microgrids. Thus, by using the Biogrid device it is possible to mechanically passage large quantities of cells in suspension cultures in closed fluidic systems, without the use of proteolytic enzymes. PMID:21850297

  11. Electromagnetic charges in aggregation phenomena.

    NASA Astrophysics Data System (ADS)

    Rioux, Claude; Slobodrian, R. J.

    Introduction The mechanism of fine particles aggregation is of great importance in many areas of research, in particular environment sciences where the state of aggregation defines the removal speed of dust from the atmosphere. The study of this mechanism is also important to understand the first stage of planet formation from the solar nebula. The aggregates formed are generally fractals and, as mentioned in the literature [1], the fractal dimensions and the site growth probability measures of the resulting fractal structures strongly depend on the properties of the forces that cause the aggregation. Theory and experimental apparatus We began this study by the aggregation between two charged particles and we are now consid-ering the aggregation between two magnetized particles. The aggregations are produced in a gas at a pressure between 10 and 1000 mbar and by using the applicable simplifications; we find that the distance (r) between the particles as a function of time (t) is given by the following equations: r=Ce(tf -t)1/3 for the electrical attraction r=Cm(tf -t)1/5 for the magnetic dipoles aligned in an external magnetic field. The apparatus built for these measurements consists of an experimental cell from which two perpendicular views are combined via an optical system in one image recorded by a video camera. From the video, we can then measure the distance between the particles as a function of time and reconstruct the trajectories in 3-D. The horizontal and vertical resolutions are respectively 0.86 and 0.92 microns per pixel. With a depth of field of 250 microns, the usable volume for 3-D observation in then 250 microns x 250 microns x 443 microns. Results and discussion A first version of the apparatus was tested on an electrical force aggregation and the results [2] show that the corresponding equation is a good representation of the phenomenon. Preliminary results, from an experiment using iron particles, show that the magnetic force can be seen in

  12. Spatial and temporal control of cell aggregation efficiently directs human pluripotent stem cells towards neural commitment.

    PubMed

    Miranda, Cláudia C; Fernandes, Tiago G; Pascoal, Jorge F; Haupt, Simone; Brüstle, Oliver; Cabral, Joaquim M S; Diogo, Maria Margarida

    2015-10-01

    3D suspension culture is generally considered a promising method to achieve efficient expansion and controlled differentiation of human pluripotent stem cells (hPSCs). In this work, we focused on developing an integrated culture platform for expansion and neural commitment of hPSCs into neural precursors using 3D suspension conditions and chemically-defined culture media. We evaluated different inoculation methodologies for hPSC expansion as 3D aggregates and characterized the resulting cultures in terms of aggregate size distribution. It was demonstrated that upon single-cell inoculation, after four days of culture, 3D aggregates were composed of homogenous populations of hPSC and were characterized by an average diameter of 139 ± 26 μm, which was determined to be the optimal size to initiate neural commitment. Temporal analysis revealed that upon neural specification it is possible to maximize the percentage of neural precursor cells expressing the neural markers Sox1 and Pax6 after nine days of culture. These results highlight our ability to define a robust method for production of hPSC-derived neural precursors that minimizes processing steps and that constitutes a promising alternative to the traditional planar adherent culture system due to a high potential for scaling-up. PMID:25866360

  13. 48 CFR 514.270 - Aggregate awards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Aggregate awards. 514.270 Section 514.270 Federal Acquisition Regulations System GENERAL SERVICES ADMINISTRATION CONTRACTING METHODS AND CONTRACT TYPES SEALED BIDDING Solicitation of Bids 514.270 Aggregate awards....

  14. Streaming instability of aggregating slime mold amoebae

    NASA Astrophysics Data System (ADS)

    Levine, Herbert; Reynolds, William

    1991-05-01

    We propose a new model of aggregation in the cellular slime mold D. Discoideum. Our approach couples the excitable signaling system to amoeba chemotaxis; the resultant system of equations is tractable to analytical and numerical approaches. Using our model, we derive the existence of a streaming instability for the concentric target aggregation pattern.

  15. Religious Dimensions of World Cultures as Related to the Holt Databank System.

    ERIC Educational Resources Information Center

    Calderwood, Beatrice

    This resource unit, part of a series of guides by the Public Religion Studies Center at Wright State University, correlates with the Holt Databank System "Inquiring About Cultures." The unit covers many facets of many cultures ranging from primitive tribes to complex, urban societies and makes evident the religious dimensions of culture in both…

  16. Social aggregation as a cooperative game

    NASA Astrophysics Data System (ADS)

    Vilone, Daniele; Guazzini, Andrea

    2011-07-01

    A new approach for the description of phenomena of social aggregation is suggested. On the basis of psychological concepts (as for instance social norms and cultural coordinates), we deduce a general mechanism for social aggregation in which different clusters of individuals can merge according to cooperation among the agents. In their turn, the agents can cooperate or defect according to the clusters' distribution inside the system. The fitness of an individual increases with the size of its cluster, but decreases with the work the individual had to do in order to join it. In order to test the reliability of such a new approach, we introduce a couple of simple toy models with the features illustrated above. We see, from this preliminary study, how cooperation is the most convenient strategy only in the presence of very large clusters, while on the other hand it is not necessary to have one hundred percent of cooperators for reaching a totally ordered configuration with only one megacluster filling the whole system.

  17. 47 CFR 10.300 - Alert aggregator. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Alert aggregator. 10.300 Section 10.300 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL COMMERCIAL MOBILE ALERT SYSTEM System Architecture § 10.300 Alert aggregator....

  18. 47 CFR 10.300 - Alert aggregator. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Alert aggregator. 10.300 Section 10.300 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL COMMERCIAL MOBILE ALERT SYSTEM System Architecture § 10.300 Alert aggregator....

  19. 47 CFR 10.300 - Alert aggregator. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Alert aggregator. 10.300 Section 10.300 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL COMMERCIAL MOBILE ALERT SYSTEM System Architecture § 10.300 Alert aggregator....

  20. Equilibrium structure of ferrofluid aggregates

    SciTech Connect

    Yoon, Mina; Tomanek, David

    2010-01-01

    We study the equilibrium structure of large but finite aggregates of magnetic dipoles, representing a colloidal suspension of magnetite particles in a ferrofluid. With increasing system size, the structural motif evolves from chains and rings to multi-chain and multi-ring assemblies. Very large systems form single- and multi-wall coils, tubes and scrolls. These structural changes result from a competition between various energy terms, which can be approximated analytically within a continuum model. We also study the effect of external parameters such as magnetic field on the relative stability of these structures. Our results may give insight into experimental data obtained during solidification of ferrofluid aggregates at temperatures where thermal fluctuations become negligible in comparison to inter-particle interactions. These data may also help to experimentally control the aggregation of magnetic particles.

  1. Fully-automated roller bottle handling system for large scale culture of mammalian cells.

    PubMed

    Kunitake, R; Suzuki, A; Ichihashi, H; Matsuda, S; Hirai, O; Morimoto, K

    1997-01-20

    A fully automatic and continuous cell culture system based on roller bottles is described in this paper. The system includes a culture rack storage station for storing a large number of roller bottles filled with culture medium and inoculated with mammalian cells, mass-handling facility for extracting completed cultures from the roller bottles, and replacing the culture medium. The various component units of the system were controlled either by a general-purpose programmable logic controller or a dedicated controller. The system provided four subsequent operation modes: cell inoculation, medium change, harvesting, and medium change. The operator could easily select and change the appropriate mode from outside of the aseptic area. The development of the system made large-scale production of mammalian cells, and manufacturing and stabilization of high quality products such as erythropoietin possible under total aseptic control, and opened up the door for industrial production of physiologically active substances as pharmaceutical drugs by mammalian cell culture.

  2. Technique for Handling Cover Slips Used in Cell Culture Systems *

    PubMed Central

    Bowne, J. G.; Jochim, Michael M.

    1964-01-01

    A stainless steel, grooved rack was designed to handle large numbers of coverslips used in cell cultures. The rack separated and held the coverslips through the washing process and subsequent manipulations. Slips washed by this method allowed consistently good cell sheets to grow with no signs of cytotoxicity to the cultures. ImagesFIGURE 1.FIGURE 2. PMID:17649500

  3. Forgotten Millions: A Case of Cultural and Systemic Bias

    ERIC Educational Resources Information Center

    Alur, Mithu

    2007-01-01

    In this article the author discusses concepts of exclusion and inclusion and how important it is to understand exclusionary practices in the context and culture specificity of each region to attempt to remove barriers to inclusive education. She specifically discusses the low status given to girls and women in the Indian culture and how this…

  4. Multispectral light metering system for cultural heritage diagnosis and conservation

    NASA Astrophysics Data System (ADS)

    Miccoli, Matteo; Melis, Marcello

    2013-05-01

    In the world of Cultural Heritage the first concern is all about Conservation of the works of art. A piece of art in bad shape is meant to deteriorate to an irreversible stage. To avoid this, quite often it's needed to go through one or more cycles of restoration to clean and consolidate the various elements of the piece. The very second concern, once the work of art is restored and in good and stable shape, is its fruition. At the end of the day why one should do all that restoration work if nobody then can access and view? Yet viewing and enjoying an artwork means that a visitor would be able to see it at its best, and this means, almost always, to have a good lighting system. Today, both restoration and fruition can greatly benefit of all the available technologies, and achieve very high level quality. The goal of this paper is the development of an exposimetric system suitable to be extremely useful as a tool for the the non invasive analysis, as well as for the lighting design and lighting systems monitoring. Many diagnosis techniques that are used before the restoration stage, require a suitable lighting system to allow to extract from the painting the maximum amount of information through the acquisition of images in the range of visible as well as UV and IR light. A standard exposimeter is for its own nature, sensitive only to the visible light, constrained by the standard photometric sensitivity curve V(lambda). A wide band exposimeter would be, on the other hand, an invaluable tool to get higher precision and to speed up multispectral wide band images acquisition, avoiding time wasting fail and try cycles to record the subject under wide spectrum conditions. The same equipment can be used to monitor the quality of the light in a expo lighting system at, for example, a museum or a gallery. The light hitting a piece of art has to allow the visitor to see and appreciate all the color shades, and to appreciate the contrast of dark and bright areas due only to

  5. Culturing Human Pluripotent and Neural Stem Cells in an Enclosed Cell Culture System for Basic and Preclinical Research.

    PubMed

    Stover, Alexander E; Herculian, Siranush; Banuelos, Maria G; Navarro, Samantha L; Jenkins, Michael P; Schwartz, Philip H

    2016-01-01

    This paper describes how to use a custom manufactured, commercially available enclosed cell culture system for basic and preclinical research. Biosafety cabinets (BSCs) and incubators have long been the standard for culturing and expanding cell lines for basic and preclinical research. However, as the focus of many stem cell laboratories shifts from basic research to clinical translation, additional requirements are needed of the cell culturing system. All processes must be well documented and have exceptional requirements for sterility and reproducibility. In traditional incubators, gas concentrations and temperatures widely fluctuate anytime the cells are removed for feeding, passaging, or other manipulations. Such interruptions contribute to an environment that is not the standard for cGMP and GLP guidelines. These interruptions must be minimized especially when cells are utilized for therapeutic purposes. The motivation to move from the standard BSC and incubator system to a closed system is that such interruptions can be made negligible. Closed systems provide a work space to feed and manipulate cell cultures and maintain them in a controlled environment where temperature and gas concentrations are consistent. This way, pluripotent and multipotent stem cells can be maintained at optimum health from the moment of their derivation all the way to their eventual use in therapy. PMID:27341536

  6. Culturing Human Pluripotent and Neural Stem Cells in an Enclosed Cell Culture System for Basic and Preclinical Research

    PubMed Central

    Stover, Alexander E.; Herculian, Siranush; Banuelos, Maria G.; Navarro, Samantha L.; Jenkins, Michael P.; Schwartz, Philip H.

    2016-01-01

    This paper describes how to use a custom manufactured, commercially available enclosed cell culture system for basic and preclinical research. Biosafety cabinets (BSCs) and incubators have long been the standard for culturing and expanding cell lines for basic and preclinical research. However, as the focus of many stem cell laboratories shifts from basic research to clinical translation, additional requirements are needed of the cell culturing system. All processes must be well documented and have exceptional requirements for sterility and reproducibility. In traditional incubators, gas concentrations and temperatures widely fluctuate anytime the cells are removed for feeding, passaging, or other manipulations. Such interruptions contribute to an environment that is not the standard for cGMP and GLP guidelines. These interruptions must be minimized especially when cells are utilized for therapeutic purposes. The motivation to move from the standard BSC and incubator system to a closed system is that such interruptions can be made negligible. Closed systems provide a work space to feed and manipulate cell cultures and maintain them in a controlled environment where temperature and gas concentrations are consistent. This way, pluripotent and multipotent stem cells can be maintained at optimum health from the moment of their derivation all the way to their eventual use in therapy. PMID:27341536

  7. 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.

  8. Does the concept of safety culture help or hinder systems thinking in safety?

    PubMed

    Reiman, Teemu; Rollenhagen, Carl

    2014-07-01

    The concept of safety culture has become established in safety management applications in all major safety-critical domains. The idea that safety culture somehow represents a "systemic view" on safety is seldom explicitly spoken out, but nevertheless seem to linger behind many safety culture discourses. However, in this paper we argue that the "new" contribution to safety management from safety culture never really became integrated with classical engineering principles and concepts. This integration would have been necessary for the development of a more genuine systems-oriented view on safety; e.g. a conception of safety in which human, technological, organisational and cultural factors are understood as mutually interacting elements. Without of this integration, researchers and the users of the various tools and methods associated with safety culture have sometimes fostered a belief that "safety culture" in fact represents such a systemic view about safety. This belief is, however, not backed up by theoretical or empirical evidence. It is true that safety culture, at least in some sense, represents a holistic term-a totality of factors that include human, organisational and technological aspects. However, the departure for such safety culture models is still human and organisational factors rather than technology (or safety) itself. The aim of this paper is to critically review the various uses of the concept of safety culture as representing a systemic view on safety. The article will take a look at the concepts of culture and safety culture based on previous studies, and outlines in more detail the theoretical challenges in safety culture as a systems concept. The paper also presents recommendations on how to make safety culture more systemic. PMID:24275532

  9. Does the concept of safety culture help or hinder systems thinking in safety?

    PubMed

    Reiman, Teemu; Rollenhagen, Carl

    2014-07-01

    The concept of safety culture has become established in safety management applications in all major safety-critical domains. The idea that safety culture somehow represents a "systemic view" on safety is seldom explicitly spoken out, but nevertheless seem to linger behind many safety culture discourses. However, in this paper we argue that the "new" contribution to safety management from safety culture never really became integrated with classical engineering principles and concepts. This integration would have been necessary for the development of a more genuine systems-oriented view on safety; e.g. a conception of safety in which human, technological, organisational and cultural factors are understood as mutually interacting elements. Without of this integration, researchers and the users of the various tools and methods associated with safety culture have sometimes fostered a belief that "safety culture" in fact represents such a systemic view about safety. This belief is, however, not backed up by theoretical or empirical evidence. It is true that safety culture, at least in some sense, represents a holistic term-a totality of factors that include human, organisational and technological aspects. However, the departure for such safety culture models is still human and organisational factors rather than technology (or safety) itself. The aim of this paper is to critically review the various uses of the concept of safety culture as representing a systemic view on safety. The article will take a look at the concepts of culture and safety culture based on previous studies, and outlines in more detail the theoretical challenges in safety culture as a systems concept. The paper also presents recommendations on how to make safety culture more systemic.

  10. Cellular strategies for regulating functional and nonfunctional protein aggregation.

    PubMed

    Gsponer, Jörg; Babu, M Madan

    2012-11-29

    Growing evidence suggests that aggregation-prone proteins are both harmful and functional for a cell. How do cellular systems balance the detrimental and beneficial effect of protein aggregation? We reveal that aggregation-prone proteins are subject to differential transcriptional, translational, and degradation control compared to nonaggregation-prone proteins, which leads to their decreased synthesis, low abundance, and high turnover. Genetic modulators that enhance the aggregation phenotype are enriched in genes that influence expression homeostasis. Moreover, genes encoding aggregation-prone proteins are more likely to be harmful when overexpressed. The trends are evolutionarily conserved and suggest a strategy whereby cellular mechanisms specifically modulate the availability of aggregation-prone proteins to (1) keep concentrations below the critical ones required for aggregation and (2) shift the equilibrium between the monomeric and oligomeric/aggregate form, as explained by Le Chatelier's principle. This strategy may prevent formation of undesirable aggregates and keep functional assemblies/aggregates under control. PMID:23168257

  11. Ethanol production from starch by a coimmobilized mixed culture system of Aspergillus awamori and Zymomonas mobilis

    SciTech Connect

    Tanaka, H.; Kurosawa, H.; Murakami, H.

    1986-01-01

    The production of ethanol from starch by a coimmobilized mixed culture system of aerobic and anaerobic microorganisms in Ca-alginate gel beads was investigated. The mold Aspergillus awamori was used as an aerobic amylolytic microorganism and an anaerobic bacterium, Zymomonas mobilis, as an ethanol producer. By controlling the mixing ratio of the microorganisms in the inoculum size, a desirable coimmobilized mixed culture system, in which the aerobic mycelia grew on and near the oxygen-rich surface of the gel beads while the anaerobic bacterial cells mainly grew in the oxygen-deficient central part of the gel beads, was naturally established under the aerobic culture conditions, and ethanol could be directly produced from starch by the system. The ethanol productivity by the system in flask culture was particularly affected by the shear stress (dependent on the shaking speed) which controlled the mycelial growth on the surface of the gel beads. Under optimum culture conditions in the flask culture, the glucose produced was instantly consumed, and was not observed in the culture broth; the final concentration of ethanol produced from 100 g/L starch was 25 g/L and the yield coefficient for ethanol, Y/sub p/s/, was 0.38. The ethanol productivity by the coimmobilized mixed culture system was compared with those by other various culture systems and the advantages of the system were clarified.

  12. Aggregation server for grid-integrated vehicles

    DOEpatents

    Kempton, Willett

    2015-05-26

    Methods, systems, and apparatus for aggregating electric power flow between an electric grid and electric vehicles are disclosed. An apparatus for aggregating power flow may include a memory and a processor coupled to the memory to receive electric vehicle equipment (EVE) attributes from a plurality of EVEs, aggregate EVE attributes, predict total available capacity based on the EVE attributes, and dispatch at least a portion of the total available capacity to the grid. Power flow may be aggregated by receiving EVE operational parameters from each EVE, aggregating the received EVE operational parameters, predicting total available capacity based on the aggregated EVE operational parameters, and dispatching at least a portion of the total available capacity to the grid.

  13. Neuronal aggregates: formation, clearance and spreading

    PubMed Central

    Lim, Junghyun; Yue, Zhenyu

    2015-01-01

    Summary Proteostasis is maintained by multiple cellular pathways, including protein synthesis, quality control and degradation. An imbalance of neuronal proteostasis, associated with protein misfolding and aggregation, leads to proteinopathies or neurodegeneration. While genetic variations and protein modifications contribute to aggregate formation, components of the proteostasis network dictate the fate of protein aggregates. Here we provide an overview of proteostasis pathways and their interplay (particularly autophagy) with the metabolism of disease-related proteins. We review recent studies on neuronal activity-mediated regulation of proteostasis and transcellular propagation of protein aggregates in the nervous system. Targeting proteostasis pathways therapeutically remains an attractive but challenging task. PMID:25710535

  14. 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

  15. Novel insights into amylin aggregation

    PubMed Central

    Pillay, Karen; Govender, Patrick

    2014-01-01

    Amylin is a peptide that aggregates into species that are toxic to pancreatic beta cells, leading to type II diabetes. This study has for the first time quantified amylin association and dissociation kinetics (association constant (ka) = 28.7 ± 5.1 L mol−1 s−1 and dissociation constant (kd) = 2.8 ± 0.6 ×10−4 s−1) using surface plasmon resonance (SPR). Thus far, techniques used for the sizing of amylin aggregates do not cater for the real-time monitoring of unconstrained amylin in solution. In this regard we evaluated recently innovated nanoparticle tracking analysis (NTA). In addition, both SPR and NTA were used to study the effect of previously synthesized amylin derivatives on amylin aggregation and to evaluate their potential as a cell-free system for screening potential inhibitors of amylin-mediated cytotoxicity. Results obtained from NTA highlighted a predominance of 100–300 nm amylin aggregates and correlation to previously published cytotoxicity results suggests the toxic species of amylin to be 200–300 nm in size. The results seem to indicate that NTA has potential as a new technique to monitor the aggregation potential of amyloid peptides in solution and also to screen potential inhibitors of amylin-mediated cytotoxicity. PMID:26019498

  16. Three-dimensional Myoblast Aggregates--Effects of Modeled Microgravity

    NASA Technical Reports Server (NTRS)

    Byerly, Diane; Sognier, M. A.; Marquette, M. L.

    2006-01-01

    The overall objective of these studies is to elucidate the molecular and cellular alterations that contribute to muscle atrophy in astronauts caused by exposure to microgravity conditions in space. To accomplish this, a three-dimensional model test system was developed using mouse myoblast cells (C2C12). Myoblast cells were grown as three-dimensional aggregates (without scaffolding or other solid support structures) in both modeled microgravity (Rotary Cell Culture System, Synthecon, Inc.) and at unit gravity in coated Petri dishes. Evaluation of H&E stained thin sections of the aggregates revealed the absence of any necrosis. Confocal microscopy evaluations of cells stained with the Live/Dead assay (Molecular Probes) confirmed that viable cells were present throughout the aggregates with an average of only three dead cells observed per aggregate. Preliminary results from gene array analysis (Affymetrix chip U74Av2) showed that approximately 14% of the genes were down regulated (decreased more than 3 fold) and 4% were upregulated in cells exposed to modeled microgravity for 12 hours compared to unit gravity controls. Additional studies using fluorescent phallacidin revealed a decrease in F-actin in the cells exposed to modeled microgravity compared to unit gravity. Myoblast cells grown as aggregates in modeled microgravity exhibited spontaneous differentiation into syncitia while no differentiation was seen in the unit gravity controls. These studies show that 1)the model test system developed is suitable for assessing cellular and molecular alterations in myoblasts; 2) gene expression alterations occur rapidly (within 12 hours) following exposure to modeled microgravity; and 3) modeled microgravity conditions stimulated myoblast cell differentiation. Achieving a greater understanding of the molecular alterations leading to muscle atrophy will eventually enable the development of cell-based countermeasures, which may be valuable for treatment of muscle diseases on

  17. A microdroplet cell culture based high frequency somatic embryogenesis system for pigeonpea, Cajanus cajan (L.) Millsp.

    PubMed

    Kumar, Nagan Udhaya; Gnanaraj, Muniraj; Sindhujaa, Vajravel; Viji, Maluventhen; Manoharan, Kumariah

    2015-09-01

    A protocol for high frequency production of somatic embryos was worked out in pigeonpea, Cajanus cajan (L.) Millsp. The protocol involved sequential employment of embryogenic callus cultures, low density cell suspension cultures and a novel microdroplet cell culture system. The microdroplet cell cultures involved culture of a single cell in 10 μI of Murashige and Skoog's medium supplemented with phytohormones, growth factors and phospholipid precursors. By employing the microdroplet cell cultures, single cells in isolation were grown into cell clones which developed somatic embryos. Further, 2,4-dichlorophenoxyacetic acid, kinetin, polyethylene glycol, putrescine, spermine, spermidine, choline chloride, ethanolamine and LiCl were supplemented to the low density cell suspension cultures and microdroplet cell cultures to screen for their cell division and somatic embryogenesis activity. Incubation of callus or the inoculum employed for low density cell suspension cultures and microdroplet cell cultures with polyethylene glycol was found critical for induction of somatic embryogenesis. Somatic embryogenesis at a frequency of 1.19, 3.16 and 6.51 per 10(6) cells was achieved in the callus, low density cell suspension cultures and microdroplet cell cultures, respectively. Advantages of employing microdroplet cell cultures for high frequency production of somatic embryos and its application in genetic transformation protocols are discussed. PMID:26548080

  18. A microdroplet cell culture based high frequency somatic embryogenesis system for pigeonpea, Cajanus cajan (L.) Millsp.

    PubMed

    Kumar, Nagan Udhaya; Gnanaraj, Muniraj; Sindhujaa, Vajravel; Viji, Maluventhen; Manoharan, Kumariah

    2015-09-01

    A protocol for high frequency production of somatic embryos was worked out in pigeonpea, Cajanus cajan (L.) Millsp. The protocol involved sequential employment of embryogenic callus cultures, low density cell suspension cultures and a novel microdroplet cell culture system. The microdroplet cell cultures involved culture of a single cell in 10 μI of Murashige and Skoog's medium supplemented with phytohormones, growth factors and phospholipid precursors. By employing the microdroplet cell cultures, single cells in isolation were grown into cell clones which developed somatic embryos. Further, 2,4-dichlorophenoxyacetic acid, kinetin, polyethylene glycol, putrescine, spermine, spermidine, choline chloride, ethanolamine and LiCl were supplemented to the low density cell suspension cultures and microdroplet cell cultures to screen for their cell division and somatic embryogenesis activity. Incubation of callus or the inoculum employed for low density cell suspension cultures and microdroplet cell cultures with polyethylene glycol was found critical for induction of somatic embryogenesis. Somatic embryogenesis at a frequency of 1.19, 3.16 and 6.51 per 10(6) cells was achieved in the callus, low density cell suspension cultures and microdroplet cell cultures, respectively. Advantages of employing microdroplet cell cultures for high frequency production of somatic embryos and its application in genetic transformation protocols are discussed.

  19. Immunogenicity of therapeutic proteins: influence of aggregation.

    PubMed

    Ratanji, Kirsty D; Derrick, Jeremy P; Dearman, Rebecca J; Kimber, Ian

    2014-01-01

    The elicitation of anti-drug antibodies (ADA) against biotherapeutics can have detrimental effects on drug safety, efficacy, and pharmacokinetics. The immunogenicity of biotherapeutics is, therefore, an important issue. There is evidence that protein aggregation can result in enhanced immunogenicity; however, the precise immunological and biochemical mechanisms responsible are poorly defined. In the context of biotherapeutic drug development and safety assessment, understanding the mechanisms underlying aggregate immunogenicity is of considerable interest. This review provides an overview of the phenomenon of protein aggregation, the production of unwanted aggregates during bioprocessing, and how the immune response to aggregated protein differs from that provoked by non-aggregated protein. Of particular interest is the nature of the interaction of aggregates with the immune system and how subsequent ADA responses are induced. Pathways considered here include 'classical' activation of the immune system involving antigen presenting cells and, alternatively, the breakdown of B-cell tolerance. Additionally, methods available to screen for aggregation and immunogenicity will be described. With an increased understanding of aggregation-enhanced immune responses, it may be possible to develop improved manufacturing and screening processes to avoid, or at least reduce, the problems associated with ADA.

  20. Effects of Conservation Tillage on Topsoil Microbial Metabolic Characteristics and Organic Carbon within Aggregates under a Rice (Oryza sativa L.) –Wheat (Triticum aestivum L.) Cropping System in Central China

    PubMed Central

    Liu, Tian-Qi; Cao, Cou-Gui; Li, Cheng-Fang

    2016-01-01

    Investigating microbial metabolic characteristics and soil organic carbon (SOC) within aggregates and their relationships under conservation tillage may be useful in revealing the mechanism of SOC sequestration in conservation tillage systems. However, limited studies have been conducted to investigate the relationship between SOC and microbial metabolic characteristics within aggregate fractions under conservation tillage. We hypothesized that close relationships can exist between SOC and microbial metabolic characteristics within aggregates under conservation tillage. In this study, a field experiment was conducted from June 2011 to June 2013 following a split-plot design of a randomized complete block with tillage practices [conventional intensive tillage (CT) and no tillage (NT)] as main plots and straw returning methods [preceding crop residue returning (S, 2100−2500 kg C ha−1) and removal (NS, 0 kg C ha-1)] as subplots with three replications. The objective of this study was to reveal the effects of tillage practices and residue-returning methods on topsoil microbial metabolic characteristics and organic carbon (SOC) fractions within aggregates and their relationships under a rice–wheat cropping system in central China. Microbial metabolic characteristics investigated using the Biolog system was examined within two aggregate fractions (>0.25 and <0.25 mm). NT treatments significantly increased SOC concentration of bulk soil, >0.25 aggregate, and <0.25 mm aggregate in the 0−5 cm soil layer by 5.8%, 6.8% and 7.9% relative to CT treatments, respectively. S treatments had higher SOC concentration of bulk soil (12.9%), >0.25 mm aggregate (11.3%), and <0.25 mm aggregate (14.1%) than NS treatments. Compared with CT treatments, NT treatments increased MBC by 11.2%, 11.5%, and 20%, and dissolved organic carbon (DOC) concentration by 15.5%, 29.5%, and 14.1% of bulk soil, >0.25 mm aggregate, and <0.25 mm aggregate in the 0−5 cm soil layer, respectively

  1. Effects of Conservation Tillage on Topsoil Microbial Metabolic Characteristics and Organic Carbon within Aggregates under a Rice (Oryza sativa L.)-Wheat (Triticum aestivum L.) Cropping System in Central China.

    PubMed

    Guo, Li-Jin; Lin, Shan; Liu, Tian-Qi; Cao, Cou-Gui; Li, Cheng-Fang

    2016-01-01

    Investigating microbial metabolic characteristics and soil organic carbon (SOC) within aggregates and their relationships under conservation tillage may be useful in revealing the mechanism of SOC sequestration in conservation tillage systems. However, limited studies have been conducted to investigate the relationship between SOC and microbial metabolic characteristics within aggregate fractions under conservation tillage. We hypothesized that close relationships can exist between SOC and microbial metabolic characteristics within aggregates under conservation tillage. In this study, a field experiment was conducted from June 2011 to June 2013 following a split-plot design of a randomized complete block with tillage practices [conventional intensive tillage (CT) and no tillage (NT)] as main plots and straw returning methods [preceding crop residue returning (S, 2100-2500 kg C ha-1) and removal (NS, 0 kg C ha(-1))] as subplots with three replications. The objective of this study was to reveal the effects of tillage practices and residue-returning methods on topsoil microbial metabolic characteristics and organic carbon (SOC) fractions within aggregates and their relationships under a rice-wheat cropping system in central China. Microbial metabolic characteristics investigated using the Biolog system was examined within two aggregate fractions (>0.25 and <0.25 mm). NT treatments significantly increased SOC concentration of bulk soil, >0.25 aggregate, and <0.25 mm aggregate in the 0-5 cm soil layer by 5.8%, 6.8% and 7.9% relative to CT treatments, respectively. S treatments had higher SOC concentration of bulk soil (12.9%), >0.25 mm aggregate (11.3%), and <0.25 mm aggregate (14.1%) than NS treatments. Compared with CT treatments, NT treatments increased MBC by 11.2%, 11.5%, and 20%, and dissolved organic carbon (DOC) concentration by 15.5%, 29.5%, and 14.1% of bulk soil, >0.25 mm aggregate, and <0.25 mm aggregate in the 0-5 cm soil layer, respectively. Compared with

  2. Effects of Conservation Tillage on Topsoil Microbial Metabolic Characteristics and Organic Carbon within Aggregates under a Rice (Oryza sativa L.)-Wheat (Triticum aestivum L.) Cropping System in Central China.

    PubMed

    Guo, Li-Jin; Lin, Shan; Liu, Tian-Qi; Cao, Cou-Gui; Li, Cheng-Fang

    2016-01-01

    Investigating microbial metabolic characteristics and soil organic carbon (SOC) within aggregates and their relationships under conservation tillage may be useful in revealing the mechanism of SOC sequestration in conservation tillage systems. However, limited studies have been conducted to investigate the relationship between SOC and microbial metabolic characteristics within aggregate fractions under conservation tillage. We hypothesized that close relationships can exist between SOC and microbial metabolic characteristics within aggregates under conservation tillage. In this study, a field experiment was conducted from June 2011 to June 2013 following a split-plot design of a randomized complete block with tillage practices [conventional intensive tillage (CT) and no tillage (NT)] as main plots and straw returning methods [preceding crop residue returning (S, 2100-2500 kg C ha-1) and removal (NS, 0 kg C ha(-1))] as subplots with three replications. The objective of this study was to reveal the effects of tillage practices and residue-returning methods on topsoil microbial metabolic characteristics and organic carbon (SOC) fractions within aggregates and their relationships under a rice-wheat cropping system in central China. Microbial metabolic characteristics investigated using the Biolog system was examined within two aggregate fractions (>0.25 and <0.25 mm). NT treatments significantly increased SOC concentration of bulk soil, >0.25 aggregate, and <0.25 mm aggregate in the 0-5 cm soil layer by 5.8%, 6.8% and 7.9% relative to CT treatments, respectively. S treatments had higher SOC concentration of bulk soil (12.9%), >0.25 mm aggregate (11.3%), and <0.25 mm aggregate (14.1%) than NS treatments. Compared with CT treatments, NT treatments increased MBC by 11.2%, 11.5%, and 20%, and dissolved organic carbon (DOC) concentration by 15.5%, 29.5%, and 14.1% of bulk soil, >0.25 mm aggregate, and <0.25 mm aggregate in the 0-5 cm soil layer, respectively. Compared with

  3. Induction of carcinoembryonic antigen expression in a three-dimensional culture system

    NASA Technical Reports Server (NTRS)

    Jessup, J. M.; Brown, D.; Fitzgerald, W.; Ford, R. D.; Nachman, A.; Goodwin, T. J.; Spaulding, G.

    1994-01-01

    MIP-101 is a poorly differentiated human colon carcinoma cell line established from ascites that produces minimal amounts of carcinoembryonic antigen (CEA), a 180 kDa glycoprotein tumor marker, and nonspecific cross-reacting antigen (NCA), a related protein that has 50 and 90 kDa isoforms, in vitro in monolayer culture. MIP-101 produces CEA when implanted into the peritoneum of nude mice but not when implanted into subcutaneous tissue. We tested whether MIP-101 cells may be induced to express CEA when cultured on microcarrier beads in three-dimensional cultures, either in static cultures as non-adherent aggregates or under dynamic conditions in a NASA-designed low shear stress bioreactor. MIP- 101 cells proliferated well under all three conditions and increased CEA and NCA production 3 - 4 fold when grown in three-dimensional cultures compared to MIP-101 cells growing logarithmically in monolayers. These results suggest that three-dimensional growth in vitro simulates tumor function in vivo and that three-dimensional growth by itself may enhance production of molecules that are associated with the metastatic process.

  4. Self-sustaining populations, population sinks or aggregates of strays: chum (Oncorhynchus keta) and Chinook salmon (Oncorhynchus tshawytscha) in the Wood River system, Alaska.

    PubMed

    Lin, Jocelyn E; Hilborn, Ray; Quinn, Thomas P; Hauser, Lorenz

    2011-12-01

    Small populations can provide insights into ecological and evolutionary aspects of species distributions over space and time. In the Wood River system in Alaska, USA, small aggregates of Chinook (Oncorhynchus tshawytscha) and chum salmon (O. keta) spawn in an area dominated by sockeye salmon (O. nerka). Our objective was to determine whether these Chinook and chum salmon are reproductively isolated, self-sustaining populations, population sinks that produce returning adults but receive immigration, or strays from other systems that do not produce returning adults. DNA samples collected from adult chum salmon from 16 streams and Chinook salmon from four streams in the Wood River system over 3 years were compared to samples from large populations in the nearby Nushagak River system, a likely source of strays. For both species, microsatellite markers indicated no significant genetic differentiation between the two systems. Simulations of microsatellite data in a large source and a smaller sink population suggested that considerable immigration would be required to counteract the diverging effects of genetic drift and produce genetic distances as small as those observed, considering the small census sizes of the two species in the Wood River system. Thus, the Wood River system likely receives substantial immigration from neighbouring watersheds, such as the Nushagak River system, which supports highly productive runs. Although no data on population productivity in the Wood River system exist, our results suggest source-sink dynamics for the two species, a finding relevant to other systems where salmonid population sizes are limited by habitat factors.

  5. Aggregation in environmental systems - Part 1: Seasonal tracer cycles quantify young water fractions, but not mean transit times, in spatially heterogeneous catchments

    NASA Astrophysics Data System (ADS)

    Kirchner, J. W.

    2016-01-01

    Environmental heterogeneity is ubiquitous, but environmental systems are often analyzed as if they were homogeneous instead, resulting in aggregation errors that are rarely explored and almost never quantified. Here I use simple benchmark tests to explore this general problem in one specific context: the use of seasonal cycles in chemical or isotopic tracers (such as Cl-, δ18O, or δ2H) to estimate timescales of storage in catchments. Timescales of catchment storage are typically quantified by the mean transit time, meaning the average time that elapses between parcels of water entering as precipitation and leaving again as streamflow. Longer mean transit times imply greater damping of seasonal tracer cycles. Thus, the amplitudes of tracer cycles in precipitation and streamflow are commonly used to calculate catchment mean transit times. Here I show that these calculations will typically be wrong by several hundred percent, when applied to catchments with realistic degrees of spatial heterogeneity. This aggregation bias arises from the strong nonlinearity in the relationship between tracer cycle amplitude and mean travel time. I propose an alternative storage metric, the young water fraction in streamflow, defined as the fraction of runoff with transit times of less than roughly 0.2 years. I show that this young water fraction (not to be confused with event-based "new water" in hydrograph separations) is accurately predicted by seasonal tracer cycles within a precision of a few percent, across the entire range of mean transit times from almost zero to almost infinity. Importantly, this relationship is also virtually free from aggregation error. That is, seasonal tracer cycles also accurately predict the young water fraction in runoff from highly heterogeneous mixtures of subcatchments with strongly contrasting transit-time distributions. Thus, although tracer cycle amplitudes yield biased and unreliable estimates of catchment mean travel times in heterogeneous

  6. A rapid method for simultaneous evaluation of free light chain content and aggregate content in culture media of Chinese hamster ovary cells expressing monoclonal antibodies for cell line screening.

    PubMed

    Ishii, Yoichi; Tsukahara, Masayoshi; Wakamatsu, Kaori

    2016-04-01

    The goal of developing a monoclonal antibody (mAb) production process is high productivity and high quality. Because the productivity and quality of mAbs depend on cell line properties, the selection of cell lines suitable for large-scale production is an important stage in process development for mAb production. The light chain (LC) is important for antibody folding and assembly in the endoplasmic reticulum; cell lines that secrete a large amount of LCs in the medium secrete high-quality antibodies with high productivity. LC contents in culture media have been estimated by western blotting, reverse-phase high-performance liquid chromatography, and enzyme-linked immunosorbent assay. However, these analyses require fine tuning of experimental conditions for each antibody analyzed. Here we report a rapid and simple high-sensitivity size-exclusion chromatography (HS-SEC) method to evaluate the contents of low-molecular weight species (LMWS, mainly consisting of LC monomers and dimers) and high-molecular weight species (HMWS, aggregates) in the media for cell line screening. Because LMWS and HMWS are important indicators of productivity and quality, respectively, for cell line screening, HS-SEC will be useful in the first step of cell line selection needed for large-scale production. PMID:26467692

  7. Revisiting the Role of Cultural Capital in East Asian Educational Systems: The Case of South Korea

    ERIC Educational Resources Information Center

    Byun, Soo-yong; Schofer, Evan; Kim, Kyung-keun

    2012-01-01

    The concept of cultural capital has proved invaluable in understanding educational systems in Western countries, and recent work seeks to extend those insights to the diverse educational systems of other geographic regions. Using data from the 2000 Programme for International Student Assessment, the authors explored cultural capital in South Korea…

  8. Growth hormone aggregates in the rat adenohypophysis

    NASA Technical Reports Server (NTRS)

    Farrington, M.; Hymer, W. C.

    1990-01-01

    Although it has been known for some time that GH aggregates are contained within the rat anterior pituitary gland, the role that they might play in pituitary function is unknown. The present study examines this issue using the technique of Western blotting, which permitted visualization of 11 GH variants with apparent mol wt ranging from 14-88K. Electroelution of the higher mol wt variants from gels followed by their chemical reduction with beta-mercaptoethanol increased GH immunoassayability by about 5-fold. With the blot procedure we found 1) that GH aggregates greater than 44K were associated with a 40,000 x g sedimentable fraction; 2) that GH aggregates were not present in glands from thyroidectomized rats, but were in glands from the thyroidectomized rats injected with T4; 3) that GH aggregates were uniquely associated with a heavily granulated somatotroph subpopulation isolated by density gradient centrifugation; and 4) that high mol wt GH forms were released from the dense somatotrophs in culture, since treatment of the culture medium with beta-mercaptoethanol increased GH immunoassayability by about 5-fold. Taken together, the results show that high mol wt GH aggregates are contained in secretory granules of certain somatotrophs and are also released in aggregate form from these cells in vitro.

  9. An analysis of the productivity of a CELSS continuous algal culture system

    NASA Technical Reports Server (NTRS)

    Radmer, R.; Behrens, P.; Fernandez, E.; Arnett, K.

    1986-01-01

    One of the most attractive aspects of using algal cultures as plant components for a Closed Ecological Life Support Systems (CELSS) is the efficiency with which they can be grown. Although algae are not necessarily intrinsically more efficient than higher plants, the ease which they can be handled and manipulated (more like chemical reagents than plants), and the culturing techniques available, result in much higher growth rates than are usually attainable with higher plants. Furthermore, preliminary experiments have demonstrated that algal growth and physiology is not detectable altered in a microgravity environment, (1) whereas the response of higher plants to zero gravity is unknown. In order to rationally design and operate culture systems, it is necessary to understand how the macroparameters of a culture system, e.g., productivity, are related to the physiological aspects of the algal culture. A first principles analysis of culture system is discussed, and a mathematical model that describes the relationship of culture productivity to the cell concentration of light-limited culture is derived. The predicted productivity vs cell concentration curve agrees well with the experimental data obtained to test this model, indicating that this model permits an accurate prediction of culture productivity given the growth parameters of the system.

  10. Magnetically-Separable and Highly-Stable Enzyme System Based on Crosslinked Enzyme Aggregates Shipped in Magnetite-Coated Mesoporous Silica

    SciTech Connect

    Lee, Jinwoo; Na, Hyon Bin; Kim, Byoung Chan; Lee, Jin Hyung; Lee, Byoungsoo; Kwak, Ja Hun; Hwang, Yosun; Park, Je-Geun; Gu, Man Bock; Kim, Jaeyun; Joo, Jin; Shin, Chae-Ho; Grate, Jay W.; Hyeon, Taeghwan; Kim, Jungbae

    2009-10-15

    Magnetically-separable and highly-stable enzyme system was developed by adsorption of enzymes in superparamagnetic hierarchically ordered mesocellular mesoporous silica (M-HMMS) and subsequent enzyme crosslinking. Superparamagnetic nanoparticles were homogeneously incorporated into hierarchically-ordered mesocellular mesoporous silica (HMMS) by the decomposition of preformed iron propionate complex. The size of incorporated superparamagnetic 15 nanoparticles was around 5 nm, generating a magnetically separable host with high pore volumes and large pores (M-HMMS). α-chymotrypsin (CT) was adsorbed into M-HMMS with high loading (~30 wt%) in less than 30 minutes. Glutaraldehyde (GA) treatment of adsorbed CT resulted in nanometer scale crosslinked enzyme aggregates in M-HMMS (CLEA-M). The activity of these CT aggregates in M-HMMS (CLEA-M-CT) was 34 times than that of simply adsorbed CT in M20 HMMS, due to an effective prevention of enzyme leaching during washing via a ship-in-a-bottle approach. CLEA-M-CT maintained the intial activity not only under shaking (250 rpm) for 30 days, but also under recycled uses of 35 times. The same approach was employed for the synthesis of CLEA-M of lipase (CLEA-M-LP), and proven to be effective in improving the loading, activity, and stability of enzyme when compared to those of adsorbed LP in M-HMMS.

  11. Supramolecular aggregates of oligosaccharides with co-solvents in ternary systems for the solubilizing approach of triamcinolone.

    PubMed

    de Medeiros, Arthur S A; Zoppi, Ariana; Barbosa, Euzébio G; Oliveira, Jonas I N; Fernandes-Pedrosa, Matheus F; Longhi, Marcela R; da Silva-Júnior, Arnóbio A

    2016-10-20

    A second compound is generally associated with oligosaccharides as a strategy to maximize the solubilizing effect for nonpolar compounds. This study elucidated the role and the mechanism whereby liquid compounds interact in these supramolecular aggregates in the solubilization of triamcinolone. Three different oligosaccharides (beta-cyclodextrin, 2-hydroxipropil-beta-cyclodextrin, and randomly methylated beta-cyclodextrin) and two potent co-solvents (triethanolamine and N-methyl pyrrolidone) were carefully evaluated by using three distinct experimental approaches. Incredibly stable complexes were formed with cyclodextrins (CDs). The structure of the complexes was elucidated by magnetic resonance spectra 2D-ROESY. The interactions of the protons of ring "A" of the drug with H(3) and H(5) protons of the CD cavity observed in the binary complexes remained in both ternary complexes. Unlike the observed ternary associations with triethanolamine, N-methyl pyrrolidone competed with the triamcinolone CD cavity and considerably decreased the stability of the complex and the solubility of the drug. The molecular dynamics (MD) and quantum mechanics:molecular mechanics (QM:MM) calculations supported that triethanolamine stabilized the drug-CD interactions for the conformer identified in the 2D-ROESY experiments, improving the quality and uniformity of the formed complex. The role played by the co-solvent in the ternary complexes depends on its specific ability to interact with the CD cavity in the presence of the drug, which can be predicted in theoretical studies to select the best candidate. PMID:27474653

  12. 47 CFR 10.300 - Alert aggregator. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Alert aggregator. 10.300 Section 10.300 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL WIRELESS EMERGENCY ALERTS System Architecture § 10.300 Alert aggregator....

  13. 47 CFR 10.300 - Alert aggregator. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Alert aggregator. 10.300 Section 10.300 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL WIRELESS EMERGENCY ALERTS System Architecture § 10.300 Alert aggregator....

  14. Growth detection failures by the nonradiometric Bactec MGIT 960 mycobacterial culture system.

    PubMed

    Peña, Jeremy A; Ferraro, Mary Jane; Hoffman, Colleen G; Branda, John A

    2012-06-01

    Mycobacterial growth in liquid culture can go undetected by automated, nonradiometric growth detection systems. In our laboratory, instrument-negative tubes from the Bactec MGIT 960 system are inspected visually for clumps suggestive of mycobacterial growth, which (if present) are examined by acid-fast smear analysis. A 3-year review demonstrated that ∼1% of instrument-negative MGIT cultures contained mycobacterial growth and that 10% of all cultures yielding mycobacteria were instrument negative. Isolates from instrument-negative MGIT cultures included both tuberculous and nontuberculous mycobacteria.

  15. Multifunctional encoding system for assessment of movable cultural heritage

    NASA Astrophysics Data System (ADS)

    Tornari, V.; Bernikola, E.; Osten, W.; Groves, R. M.; Marc, G.; Hustinx, G. M.; Kouloumpi, E.; Hackney, S.

    2007-07-01

    This is an introductory paper of a recent EC project dealing with research in cultural heritage and aiming to communicate new fields of application for optical metrology techniques. The project is in its initial state and more conclusive information is expected to be available at the time of the perspective conference. Nowadays safety, ethical, economical and security issues as well as the increase demand for loaning of art objects for exhibitions in transit, are forcing the Conservation Community to undertake strong initiatives and actions against various types of mistreatment, damage or fraud, during transportation of movable Cultural Heritage. Therefore the interest directs to the development of innovative methodologies and instrumentation to respond to critical aspects of increased importance in cultural heritage preservation, among which of prior consideration are: to secure proper treatment, assess probable damage, fight fraud actions in transportation.

  16. A dual-color luciferase assay system reveals circadian resetting of cultured fibroblasts by co-cultured adrenal glands.

    PubMed

    Noguchi, Takako; Ikeda, Masaaki; Ohmiya, Yoshihiro; Nakajima, Yoshihiro

    2012-01-01

    In mammals, circadian rhythms of various organs and tissues are synchronized by pacemaker neurons in the suprachiasmatic nucleus (SCN) of the hypothalamus. Glucocorticoids released from the adrenal glands can synchronize circadian rhythms in other tissues. Many hormones show circadian rhythms in their plasma concentrations; however, whether organs outside the SCN can serve as master synchronizers to entrain circadian rhythms in target tissues is not well understood. To further delineate the function of the adrenal glands and the interactions of circadian rhythms in putative master synchronizing organs and their target tissues, here we report a simple co-culture system using a dual-color luciferase assay to monitor circadian rhythms separately in various explanted tissues and fibroblasts. In this system, circadian rhythms of organs and target cells were simultaneously tracked by the green-emitting beetle luciferase from Pyrearinus termitilluminans (ELuc) and the red-emitting beetle luciferase from Phrixothrix hirtus (SLR), respectively. We obtained tissues from the adrenal glands, thyroid glands, and lungs of transgenic mice that expressed ELuc under control of the promoter from a canonical clock gene, mBmal1. The tissues were co-cultured with Rat-1 fibroblasts as representative target cells expressing SLR under control of the mBmal1 promoter. Amplitudes of the circadian rhythms of Rat-1 fibroblasts were potentiated when the fibroblasts were co-cultured with adrenal gland tissue, but not when co-cultured with thyroid gland or lung tissue. The phases of Rat-1 fibroblasts were reset by application of adrenal gland tissue, whereas the phases of adrenal gland tissue were not influenced by Rat-1 fibroblasts. Furthermore, the effect of the adrenal gland tissue on the fibroblasts was blocked by application of a glucocorticoid receptor (GR) antagonist. These results demonstrate that glucocorticoids are strong circadian synchronizers for fibroblasts and that this co-culture

  17. [Evaluation for anaerobic culture system: Anoxomat Mart II].

    PubMed

    Kikuchi, Yuji; Sasaki, Hiromi; Furuhata, Yukie; Tazawa, Yoko; Horiuchi, Hajime; Okada, Jun

    2007-01-01

    Anoxomat Mart II (Mart Microbiology BV, Lichtenvooorde, Netherlands, Central Scientific Commerce Inc., Tokyo, Japan) is an anaerobic jar apparatus which uses a vacuum pump in combination with catalyst as gas replacement procedure to remove all traces of oxygen. As we had a chance to use Anoxomat Mart II, we compared it with other two anaerobic culture methods; namely AnaeroPack anaero (Mitsubishi Gas Chemical Co., Tokyo, Japan) which employs anaerobic jar method, and Concept400 (RUSKINN TECHNOLOGY LTD, England; Central Scientific Commerce INc., Tokyo, Japan) which uses anaerobic chamber method. We used 10 different species of anaerobic bacteria obtained from ATCC. One strain each of 10 species was cultured and examined for measurement of the sensitibity of an anaerobic indicator, th number of bacteria after 48 hour culture, the diameter of colonies, and MIC value. As a result, the time to reach the anaerobic condition was around 30 minutes by the Mart II against around 60 minutes by the AnaeroPack anaero. There was no difference concerning the number of bacteria after 48 hour culture among three methods. But anaerobic bacteria cultured by Mart II tended to make bigger colonies compared to other two methods in the 5 strains out of 9, except for one strain in which the diameter of colonies could not be measured. On the other hand, the comparison of MIC value showed good correlation in 11 antibiotics out of 12 among three methods. The MIC value of 11 antibiotics fitted within 1-fold difference, and 2-fold difference was observed in only one antibiotic. Mart II is so small that it does cheep consumables. From these reasons, we concluded that Mart II can be one of the useful anerobic culture methods.

  18. An Easy-to-Use Polystyrene Microchip-based Cell Culture System.

    PubMed

    Tazawa, Hidekatsu; Sunaoshi, Shohei; Tokeshi, Manabu; Kitamori, Takehiko; Ohtani-Kaneko, Ritsuko

    2016-01-01

    In this study, we developed an integrated, low-cost microfluidic cell culture system that is easy to use. This system consists of a disposable polystyrene microchip, a polytetrafluoroethylene valve, an air bubble trap, and an indium tin oxide temperature controller. Valve pressure resistance was validated with a manometer to be 3 MPa. The trap protected against bubble contamination. The temperature controller enabled the culture of Macaca mulatta RF/6A 135 vascular endothelial cells, which are difficult to culture in glass microchips, without a CO2 incubator. We determined the optimal coating conditions for these cells and were able to achieve stable, confluent culture within 1 week. This practical system is suitable for low-cost screening and has potential applications as circulatory cell culture systems and research platforms in cell biology. PMID:26960617

  19. Long-term maintenance of human induced pluripotent stem cells by automated cell culture system.

    PubMed

    Konagaya, Shuhei; Ando, Takeshi; Yamauchi, Toshiaki; Suemori, Hirofumi; Iwata, Hiroo

    2015-01-01

    Pluripotent stem cells, such as embryonic stem cells and induced pluripotent stem (iPS) cells, are regarded as new sources for cell replacement therapy. These cells can unlimitedly expand under undifferentiated conditions and be differentiated into multiple cell types. Automated culture systems enable the large-scale production of cells. In addition to reducing the time and effort of researchers, an automated culture system improves the reproducibility of cell cultures. In the present study, we newly designed a fully automated cell culture system for human iPS maintenance. Using an automated culture system, hiPS cells maintained their undifferentiated state for 60 days. Automatically prepared hiPS cells had a potency of differentiation into three germ layer cells including dopaminergic neurons and pancreatic cells. PMID:26573336

  20. Characterization of Ovine Dermal Papilla Cell Aggregation

    PubMed Central

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

    2016-01-01

    Context: The dermal papilla (DP) is a condensation of mesenchymal cells at the proximal end of the hair follicle, which determines hair shaft size and regulates matrix cell proliferation and differentiation. DP cells have the ability to regenerate new hair follicles. These cells tend to aggregate both in vitro and in vivo. This tendency is associated with the ability of papilla cells to induce hair growth. However, human papilla cells lose their hair-inducing activity in later passage number. Ovine DP cells are different from human DP cells since they do not lose their aggregative behavior or hair-inducing activity in culture. Nonetheless, our understanding of ovine DP cells is still limited. Aim: The aim of this study was to observe the expression of established DP markers in ovine cells and their association with aggregation. Subjects and Methods: Ovine DP cells from three different sheep were compared. Histochemistry, immunoflourescence, and polymerase chain reaction experiments were done to analyze the DP markers. Results: We found that ovine DP aggregates expressed all the 16 markers evaluated, including alkaline phosphatase and versican. Expression of the versican V0 and V3 isoforms, neural cell adhesion molecule, and corin was increased significantly with aggregation, while hey-1 expression was significantly decreased. Conclusions: Overall, the stable expression of numerous markers suggests that aggregating ovine DP cells have a similar phenotype to papillae in vivo. The stability of their molecular phenotype is consistent with their robust aggregative behavior and retained follicle-inducing activity after prolonged culture. Their phenotypic stability in culture contrasts with DP cells from other species, and suggests that a better understanding of ovine DP cells might provide opportunities to improve the hair-inducing activity and therapeutic potential of human cells. PMID:27625564

  1. Characterization of Ovine Dermal Papilla Cell Aggregation

    PubMed Central

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

    2016-01-01

    Context: The dermal papilla (DP) is a condensation of mesenchymal cells at the proximal end of the hair follicle, which determines hair shaft size and regulates matrix cell proliferation and differentiation. DP cells have the ability to regenerate new hair follicles. These cells tend to aggregate both in vitro and in vivo. This tendency is associated with the ability of papilla cells to induce hair growth. However, human papilla cells lose their hair-inducing activity in later passage number. Ovine DP cells are different from human DP cells since they do not lose their aggregative behavior or hair-inducing activity in culture. Nonetheless, our understanding of ovine DP cells is still limited. Aim: The aim of this study was to observe the expression of established DP markers in ovine cells and their association with aggregation. Subjects and Methods: Ovine DP cells from three different sheep were compared. Histochemistry, immunoflourescence, and polymerase chain reaction experiments were done to analyze the DP markers. Results: We found that ovine DP aggregates expressed all the 16 markers evaluated, including alkaline phosphatase and versican. Expression of the versican V0 and V3 isoforms, neural cell adhesion molecule, and corin was increased significantly with aggregation, while hey-1 expression was significantly decreased. Conclusions: Overall, the stable expression of numerous markers suggests that aggregating ovine DP cells have a similar phenotype to papillae in vivo. The stability of their molecular phenotype is consistent with their robust aggregative behavior and retained follicle-inducing activity after prolonged culture. Their phenotypic stability in culture contrasts with DP cells from other species, and suggests that a better understanding of ovine DP cells might provide opportunities to improve the hair-inducing activity and therapeutic potential of human cells.

  2. In vivo bone regeneration using tubular perfusion system bioreactor cultured nanofibrous scaffolds.

    PubMed

    Yeatts, Andrew B; Both, Sanne K; Yang, Wanxun; Alghamdi, Hamdan S; Yang, Fang; Fisher, John P; Jansen, John A

    2014-01-01

    The use of bioreactors for the in vitro culture of constructs for bone tissue engineering has become prevalent as these systems may improve the growth and differentiation of a cultured cell population. Here we utilize a tubular perfusion system (TPS) bioreactor for the in vitro culture of human mesenchymal stem cells (hMSCs) and implant the cultured constructs into rat femoral condyle defects. Using nanofibrous electrospun poly(lactic-co-glycolic acid)/poly(ε-caprolactone) scaffolds, hMSCs were cultured for 10 days in vitro in the TPS bioreactor with cellular and acellular scaffolds cultured statically for 10 days as a control. After 3 and 6 weeks of in vivo culture, explants were removed and subjected to histomorphometric analysis. Results indicated more rapid bone regeneration in defects implanted with bioreactor cultured scaffolds with a new bone area of 1.23 ± 0.35 mm(2) at 21 days compared to 0.99 ± 0.43 mm(2) and 0.50 ± 0.29 mm(2) in defects implanted with statically cultured scaffolds and acellular scaffolds, respectively. At the 21 day timepoint, statistical differences (p<0.05) were only observed between defects implanted with cell containing scaffolds and the acellular control. After 42 days, however, defects implanted with TPS cultured scaffolds had the greatest new bone area with 1.72 ± 0.40 mm(2). Defects implanted with statically cultured and acellular scaffolds had a new bone area of 1.26 ± 0.43 mm(2) and 1.19 ± 0.33 mm(2), respectively. The increase in bone growth observed in defects implanted with TPS cultured scaffolds was statistically significant (p<0.05) when compared to both the static and acellular groups at this timepoint. This study demonstrates the efficacy of the TPS bioreactor to improve bone tissue regeneration and highlights the benefits of utilizing perfusion bioreactor systems to culture MSCs for bone tissue engineering.

  3. Can intra-aggregate pore structures affect the aggregate's effectiveness in protecting carbon?

    SciTech Connect

    Ananyeva, K; Wang, W; Smucker, A J.M.; Rivers, M L; Kravchenko, A N

    2012-11-15

    Aggregates are known to provide physical protection to soil organic matter shielding it from rapid decomposition. Spatial arrangement and size distribution of intra-aggregate pores play an important role in this process. This study examined relationships between intra-aggregate pores measured using X-ray computed micro-tomography images and concentrations of total C in 4–6 mm macro-aggregates from two contrasting land use and management practices, namely, conventionally tilled and managed row crop agricultural system (CT) and native succession vegetation converted from tilled agricultural land in 1989 (NS). Previous analyses of these aggregates indicated that small (<15 μm) and large (>100 μm) pores prevail in NS aggregates while medium (30–90 μm) pores are more abundant in CT aggregates (Kravchenko et al., 2011; Wang et al., 2012). We hypothesized that these differences in pore size distributions affect the ability of macro-aggregates to protect C. The results of this study supported this hypothesis. Consistent with greater heterogeneity of pore distributions within NS aggregates we observed higher total C and greater intra-aggregate C variability in NS as compared with CT aggregates. Total C concentrations and intra-aggregate C standard deviations were negatively correlated with fractions of medium sized pores, indicating that presence of such pores was associated with lower but more homogeneously distributed total C. While total C was positively correlated with presence of small and large pores. The results suggest that because of their pore structure NS macro-aggregates provide more effective physical protection to C than CT aggregates.

  4. Aggregation in environmental systems - Part 2: Catchment mean transit times and young water fractions under hydrologic nonstationarity

    NASA Astrophysics Data System (ADS)

    Kirchner, J. W.

    2016-01-01

    Methods for estimating mean transit times from chemical or isotopic tracers (such as Cl-, δ18O, or δ2H) commonly assume that catchments are stationary (i.e., time-invariant) and homogeneous. Real catchments are neither. In a companion paper, I showed that catchment mean transit times estimated from seasonal tracer cycles are highly vulnerable to aggregation error, exhibiting strong bias and large scatter in spatially heterogeneous catchments. I proposed the young water fraction, which is virtually immune to aggregation error under spatial heterogeneity, as a better measure of transit times. Here I extend this analysis by exploring how nonstationarity affects mean transit times and young water fractions estimated from seasonal tracer cycles, using benchmark tests based on a simple two-box model. The model exhibits complex nonstationary behavior, with striking volatility in tracer concentrations, young water fractions, and mean transit times, driven by rapid shifts in the mixing ratios of fluxes from the upper and lower boxes. The transit-time distribution in streamflow becomes increasingly skewed at higher discharges, with marked increases in the young water fraction and decreases in the mean water age, reflecting the increased dominance of the upper box at higher flows. This simple two-box model exhibits strong equifinality, which can be partly resolved by simple parameter transformations. However, transit times are primarily determined by residual storage, which cannot be constrained through hydrograph calibration and must instead be estimated by tracer behavior. Seasonal tracer cycles in the two-box model are very poor predictors of mean transit times, with typical errors of several hundred percent. However, the same tracer cycles predict time-averaged young water fractions (Fyw) within a few percent, even in model catchments that are both nonstationary and spatially heterogeneous (although they may be biased by roughly 0.1-0.2 at sites where strong

  5. The JGrass-NewAge system for forecasting and managing the hydrological budgets at the basin scale: the models of flow generation, propagation, and aggregation

    NASA Astrophysics Data System (ADS)

    Formetta, G.; Mantilla, R.; Franceschi, S.; Antonello, A.; Rigon, R.

    2011-04-01

    This paper presents a discussion of the predictive capacity of the first implementation of the semi-distributed hydrological modeling system JGrass-NewAge. This model focuses on the hydrological balance of medium scale to large scale basins, and considers statistics of the processes at the hillslope scale. The whole modeling system consists of six main parts: (i) estimation of energy balance; (ii) estimation of evapotranspiration; (iii) snow modelling; (iv) estimation of runoff production; (v) aggregation and propagation of flows in channel, and (vi) description of intakes, out-takes, and reservoirs. This paper details the processes, of runoff production, and aggregation/propagation of flows on a river network. The system is based on a hillslope-link geometrical partition of the landscape, so the basic unit, where the budget is evaluated, consists of hillslopes that drain into a single associated link rather than cells or pixels. To this conceptual partition corresponds an implementation of informatics that uses vectorial features for channels, and raster data for hillslopes. Runoff production at each channel link is estimated through a combination of the Duffy (1996) model and a GIUH model for estimating residence times in hillslope. Routing in channels uses equations integrated for any channels' link, and produces discharges at any link end, for any link in the river network. The model has been tested against measured discharges according to some indexes of goodness of fit such as RMSE and Nash Sutcliffe. The characteristic ability to reproduce discharge in any point of the river network is used to infer some statistics, and notably, the scaling properties of the modeled discharge.

  6. 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)

  7. A Systemic Approach to Culturally Responsive Assessment Practices and Evaluation

    ERIC Educational Resources Information Center

    Slee, June

    2010-01-01

    In an earlier paper, Slee and Keenan demonstrated that it was possible for tertiary education institutions to design culturally responsive assessment procedures that complied with standardised assessment policy. The authors' paper described "Growing Our Own," an initiative between Charles Darwin University and Northern Territory Catholic…

  8. Design and Evaluation of a Cross-Cultural Training System

    NASA Technical Reports Server (NTRS)

    Santarelli, Thomas; Stagl, Kevin C.

    2011-01-01

    Cross-cultural competency, and the underlying communication and affective skills required to develop such expertise, is becoming increasingly important for a wide variety of domains. To address this need, we developed a blended learning platform which combines virtual role-play with tutorials, assessment and feedback. A Middle-Eastern Curriculum (MEC) exemplar for cross-cultural training U.S. military personnel was developed to guide the refinement of an existing game-based training platform. To complement this curriculum, we developed scenario authoring tools to enable end-users to define training objectives, link performance measures and feedback/remediation to these objectives, and deploy experiential scenarios within a game-based virtual environment (VE). Lessons learned from the design and development of this exemplar cross-cultural competency curriculum, as well as formative evaluation results, are discussed. Initial findings suggest that the underlying training technology promotes deep levels of semantic processing of the key information of relevant cultural and communication skills.

  9. Bridging the Two Cultures: Disciplinary Divides and Educational Reward Systems

    ERIC Educational Resources Information Center

    Schiferl, E. I.

    2007-01-01

    In 1959 C.P. Snow believed that communication and education could span the cultural gap between the sciences and the humanities. In the twenty-first century, language, research models, and academic structures hinder intellectual communication between art history, cognitive neuroscience and perceptual psychology--three disciplines dedicated to…

  10. Educational Policy vs. Culturally Sensitive Programs in Turkish Educational System

    ERIC Educational Resources Information Center

    Arslan, Hasan

    2009-01-01

    The purpose of this study is to examine the perceptions of elementary school teachers about the sensitiveness of principals, teachers, and curriculum on multicultural education. Education provides the transmission and the advancement of its culture while it is developing and enhancing the common values, the integrity and the progress of…

  11. Culture & Clay: The Reshaping of an Educational System.

    ERIC Educational Resources Information Center

    Levy, Linda Jean

    The validity of Bilingual Education in a multi-cultural preschool setting is examined and supported. Further, a discussion of how mental health may be linked to the recognition of a child's native language, in his aquisition of a positive self-concept, is delineated. Additionally, theoretical information is supported by a survey completed in 1976,…

  12. Modular plant culture systems for life support functions

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The current state of knowledge with regard to culture of higher plants in the zero-G environment is assessed; and concepts for the empirical development of small plant growth chambers for the production of salad type vegetables on space shuttle or space station are evaluated. American and Soviet space flight experiences in gravitational biology are summarized.

  13. Algal culture studies related to a Closed Ecological Life Support System (CELSS)

    NASA Technical Reports Server (NTRS)

    Radmer, R.; Behrens, P.; Fernandez, E.; Ollinger, O.; Howell, C.; Venables, A.; Huggins, D.; Gladue, R.

    1984-01-01

    In many respects, algae would be the ideal plant component for a biologically based controlled life support system, since they are eminently suited to the closely coupled functions of atmosphere regeneration and food production. Scenedesmus obliquus and Spirulina platensis were grown in three continuous culture apparatuses. Culture vessels their operation and relative merits are described. Both light and nitrogen utilization efficiency are examined. Long term culture issues are detailed and a discussion of a plasmid search in Spirulina is included.

  14. Higher recovery rate of microorganisms from cerebrospinal fluid samples by the BACTEC culture system in comparison with agar culture.

    PubMed

    Calderaro, Adriana; Martinelli, Monica; Montecchini, Sara; Motta, Federica; Covan, Silvia; Larini, Sandra; Medici, Maria Cristina; Arcangeletti, Maria Cristina; Chezzi, Carlo; De Conto, Flora

    2016-04-01

    The aim of this study was to assess the diagnostic value of the BACTEC FX blood culture (BC) system as compared to the agar culture (AC) of cerebrospinal fluid samples (CSF), evaluating the recovery rate and the time to detection of microorganisms in a 3.5-year period. From December 2011 to May 2015, 1326 CSF samples (694 patients) were submitted to both AC and BC. Among the 150 positive samples (96 patients), 165 microorganisms were detected: 81 by both the protocols, 77 by BC alone, and 7 by AC alone, demonstrating a higher detection rate of BC (95.8%) than AC (53.3%). Although BC presents some disadvantages, it is able to improve the yield of clinically significant microorganisms, and it could potentially reduce the reporting time as compared to AC. The results obtained highlighted the necessity of a combined approach for the successful detection of central nervous system microbial infections. PMID:26867963

  15. Higher recovery rate of microorganisms from cerebrospinal fluid samples by the BACTEC culture system in comparison with agar culture.

    PubMed

    Calderaro, Adriana; Martinelli, Monica; Montecchini, Sara; Motta, Federica; Covan, Silvia; Larini, Sandra; Medici, Maria Cristina; Arcangeletti, Maria Cristina; Chezzi, Carlo; De Conto, Flora

    2016-04-01

    The aim of this study was to assess the diagnostic value of the BACTEC FX blood culture (BC) system as compared to the agar culture (AC) of cerebrospinal fluid samples (CSF), evaluating the recovery rate and the time to detection of microorganisms in a 3.5-year period. From December 2011 to May 2015, 1326 CSF samples (694 patients) were submitted to both AC and BC. Among the 150 positive samples (96 patients), 165 microorganisms were detected: 81 by both the protocols, 77 by BC alone, and 7 by AC alone, demonstrating a higher detection rate of BC (95.8%) than AC (53.3%). Although BC presents some disadvantages, it is able to improve the yield of clinically significant microorganisms, and it could potentially reduce the reporting time as compared to AC. The results obtained highlighted the necessity of a combined approach for the successful detection of central nervous system microbial infections.

  16. Flow Partitioning in Fully Saturated Soil Aggregates

    SciTech Connect

    Yang, Xiaofan; Richmond, Marshall C.; Scheibe, Timothy D.; Perkins, William A.; Resat, Haluk

    2014-03-30

    Microbes play an important role in facilitating organic matter decomposition in soils, which is a major component of the global carbon cycle. Microbial dynamics are intimately coupled to environmental transport processes, which control access to labile organic matter and other nutrients that are needed for the growth and maintenance of microorganisms. Transport of soluble nutrients in the soil system is arguably most strongly impacted by preferential flow pathways in the soil. Since the physical structure of soils can be characterized as being formed from constituent micro aggregates which contain internal porosity, one pressing question is the partitioning of the flow among the “inter-aggregate” and “intra-aggregate” pores and how this may impact overall solute transport within heterogeneous soil structures. The answer to this question is particularly important in evaluating assumptions to be used in developing upscaled simulations based on highly-resolved mechanistic models. We constructed a number of diverse multi-aggregate structures with different packing ratios by stacking micro-aggregates containing internal pores and varying the size and shape of inter-aggregate pore spacing between them. We then performed pore-scale flow simulations using computational fluid dynamics methods to determine the flow patterns in these aggregate-of-aggregates structures and computed the partitioning of the flow through intra- and inter-aggregate pores as a function of the spacing between the aggregates. The results of these numerical experiments demonstrate that soluble nutrients are largely transported via flows through inter-aggregate pores. Although this result is consistent with intuition, we have also been able to quantify the relative flow capacity of the two domains under various conditions. For example, in our simulations, the flow capacity through the aggregates (intra-aggregate flow) was less than 2% of the total flow when the spacing between the aggregates

  17. Effective enrichment of cholangiocarcinoma secretomes using the hollow fiber bioreactor culture system.

    PubMed

    Weeraphan, Churat; Diskul-Na-Ayudthaya, Penchatr; Chiablaem, Khajeelak; Khongmanee, Amnart; Chokchaichamnankit, Daranee; Subhasitanont, Pantipa; Svasti, Jisnuson; Srisomsap, Chantragan

    2012-09-15

    The Northeastern region of Thailand is well known to have high incidence of bile duct cancer known as cholangiocarcinoma. So there is a continued need to improve diagnosis and treatment, and discovery of biomarkers for early detection of bile duct cancer should greatly improve treatment outcome for these patients. The secretome, a collection of proteins secreted from cells, is a useful source for identifying circulating biomarkers in blood secreted from cancer cells. Here a Hollow Fiber Bioreactor culture system was used for enrichment of cholangiocarcinoma secretomes, since this culture system mimics the dense three-dimensional microenvironment of the tumor found in vivo. Two-dimensional fluorescence difference gel electrophoresis using a sensitive Fluor saturation dye staining, followed by LC/MS/MS, was used to compare protein expression in the secretomes of cells cultured in the Hollow Fiber system and cells cultured in the monolayer culture system. For the first time, the 2D-patterns of cholangiocarcinoma secretomes from the two culture systems could be compared. The Hollow Fiber system improved the quality and quantity of cholangiocarcinoma secreted proteins compared to conventional monolayer system, showing less interference by cytoplasmic proteins and yielding more secreted proteins. Overall, 75 spots were analyzed by LC/MS/MS and 106 secreted proteins were identified. Two novel secreted proteins (C19orf10 and cystatin B) were found only in the Hollow Fiber system and were absent from the traditional monolayer culture system. Among the highly expressed proteins, 22 secreted soluble proteins were enriched by 5 fold in Hollow Fiber system compared to monolayer culture system. The Hollow Fiber system is therefore useful for preparing a wide range of proteins from low-abundance cell secretomes.

  18. The Aggregation of Four Reconstructed Zygotes is the Limit to Improve the Developmental Competence of Cloned Equine Embryos

    PubMed Central

    Gambini, Andrés; De Stefano, Adrian; Bevacqua, Romina Jimena; Karlanian, Florencia; Salamone, Daniel Felipe

    2014-01-01

    Embryo aggregation has been demonstrated to improve cloning efficiency in mammals. However, since no more than three embryos have been used for aggregation, the effect of using a larger number of cloned zygotes is unknown. Therefore, the goal of the present study was to determine whether increased numbers of cloned aggregated zygotes results in improved in vitro and in vivo embryo development in the equine. Zona-free reconstructed embryos (ZFRE's) were cultured in the well of the well system in four different experimental groups: I. 1x, only one ZFRE per microwell; II. 3x, three per microwell; III. 4x, four per microwell; and IV. 5x, five ZFRE's per microwell. Embryo size was measured on day 7, after which blastocysts from each experimental group were either a) maintained in culture from day 8 until day 16 to follow their growth rates, b) fixed to measure DNA fragmentation using the TUNEL assay, or c) transferred to synchronized mares. A higher blastocyst rate was observed on day 7 in the 4x group than in the 5x group. Non-aggregated embryos were smaller on day 8 compared to those aggregated, but from then on the in vitro growth was not different among experimental groups. Apoptotic cells averaged 10% of total cells of day 8 blastocysts, independently of embryo aggregation. Only pregnancies resulting from the aggregation of up to four embryos per microwell went beyond the fifth month of gestation, and two of these pregnancies, derived from experimental groups 3x and 4x, resulted in live cloned foals. In summary, we showed that the in vitro and in vivo development of cloned zona-free embryos improved until the aggregation of four zygotes and declined when five reconstructed zygotes were aggregated. PMID:25396418

  19. Algal culture studies related to a Closed Ecological Life Support System (CELSS)

    NASA Technical Reports Server (NTRS)

    Radmer, R. O.; Ollinger, O.; Venables, A.; Fernandez, E.

    1982-01-01

    Studies with algal cultures which relate to closed ecological life support systems (CELSS) are discussed. A description of a constant cell density apparatus for continuous culture of algae is included. Excretion of algal by-products, and nitrogen utilization and excretion are discussed.

  20. The Relationship between National Culture and the Usability of an E-Learning System

    ERIC Educational Resources Information Center

    Adeoye, Blessing; Wentling, Rose Mary

    2007-01-01

    The purpose of this study was to investigate possible relationships between national culture and the usability of an e-learning system. The theoretical frameworks that were used to guide this study were Hofstede's (1980) cultural dimensions, and Nielson's (1993) usability attributes. The sample for this study was composed of 24 international…

  1. Multiple Embedded Inequalities and Cultural Diversity in Educational Systems: A Theoretical and Empirical Exploration

    ERIC Educational Resources Information Center

    Verhoeven, Marie

    2011-01-01

    This article explores the social construction of cultural diversity in education, with a view to social justice. It examines how educational systems organize ethno-cultural difference and how this process contributes to inequalities. Theoretical resources are drawn from social philosophy as well as from recent developments in social organisation…

  2. MOSAICA: A Web-2.0 Based System for the Preservation and Presentation of Cultural Heritage

    ERIC Educational Resources Information Center

    Barak, Miri; Herscoviz, Orit; Kaberman, Zvia; Dori, Yehudit J.

    2009-01-01

    The question of how to present cultural heritage resources in a way that attracts potential users is becoming important in our ever-changing world. This paper describes MOSAICA system--a web 2.0-based toolbox, dedicated for the preservation and presentation of cultural heritage. This paper also describes an evaluation study that examined MOSAICA…

  3. Succession of Protists on Estuarine Aggregates.

    PubMed

    Wörner; Zimmerman-Timm; Kausch

    2000-08-01

    Colonization by and succession of bacteria and bacterivorous protists on laboratory-made aggregates were determined over a period of 14 days during winter and spring in 1997. Aggregates were generated from natural water from the limnetic zone of the Elbe Estuary using a tilting tube roller system. Within 1 h after the beginning of the experiments, macroaggregates started to form. Aggregates reached a maximum size of 1 mm with a tendency toward large sizes at the end of the experiment after the 10th day. On the first day, high bacterial densities of more than 10(9) cells ml(-1) were detected within the aggregates. The abundances of flagellates and ciliates within aggregates were also two or three orders of magnitude higher than in the surrounding water. Densities of aggregate associated organisms are comparable to those occuring in sediments. The first protistan colonizers on the aggregates were small heterotrophic flagellates, such as choanoflagellates and small euglenids. Later, beginning on the 4th day, small sarcodines and ciliates became abundant. The most abundant ciliates associated with aggregates were small species of the Hypotrichia, Cyrtophorida, and Hymenostomata. After 9 days, large omnivorous and carnivorous ciliates, such as large members of the Hypotrichia and the Pleurostomatida, occurred. In spring, large heterotrophic flagellates and amebae also appeared at this time. These findings indicated the existence of a succession of protists on newly formed aggregates and a microbial food net within the aggregates based on bacterial production. Additionally, most of the species observed during this study were adapted for living on surfaces. In natural environments they are more common in benthic than in pelagic environments. For them, aggregates are havens in the water column comparable to sediment communities.

  4. Generation of Aggregates of Mouse Embryonic Stem Cells that Show Symmetry Breaking, Polarization and Emergent Collective Behaviour In Vitro

    PubMed Central

    Baillie-Johnson, Peter; van den Brink, Susanne Carina; Balayo, Tina; Turner, David Andrew; Martinez Arias, Alfonso

    2015-01-01

    We have developed a protocol improving current Embryoid Body (EB) culture which allows the study of self-organization, symmetry breaking, axial elongation and cell fate specification using aggregates of mouse embryonic stem cells (mESCs) in suspension culture. Small numbers of mESCs are aggregated in basal medium for 48 hr in non-tissue-culture-treated, U-bottomed 96-well plates, after which they are competent to respond to experimental signals. Following treatment, these aggregates begin to show signs of polarized gene expression and gradually alter their morphology from a spherical mass of cells to an elongated, well organized structure in the absence of external asymmetry cues. These structures are not only able to display markers of the three germ layers, but actively display gastrulation-like movements, evidenced by a directional dislodgement of individual cells from the aggregate, which crucially occurs at one region of the elongated structure. This protocol provides a detailed method for the reproducible formation of these aggregates, their stimulation with signals such as Wnt/β-Catenin activation and BMP inhibition and their analysis by single time-point or time-lapse fluorescent microscopy. In addition, we describe modifications to current whole-mount mouse embryo staining procedures for immunocytochemical analysis of specific markers within fixed aggregates. The changes in morphology, gene expression and length of the aggregates can be quantitatively measured, providing information on how signals can alter axial fates. It is envisaged that this system can be applied both to the study of early developmental events such as axial development and organization, and more broadly, the processes of self-organization and cellular decision-making. It may also provide a suitable niche for the generation of cell types present in the embryo that are unobtainable from conventional adherent culture such as spinal cord and motor neurones. PMID:26650833

  5. Progressive aggregation of Tomato yellow leaf curl virus coat protein in systemically infected tomato plants, susceptible and resistant to the virus.

    PubMed

    Gorovits, Rena; Moshe, Adi; Kolot, Mikhail; Sobol, Iris; Czosnek, Henryk

    2013-01-01

    Tomato yellow leaf curl virus (TYLCV) coat protein (CP) accumulated in tomato leaves during infection. The CP was immuno-detected in the phloem associated cells. At the early stages of infection, punctate signals were detected in the cytoplasm, while in the later stages aggregates of increasing size were localized in cytoplasm and nuclei. Sedimentation of protein extracts through sucrose gradients confirmed that progress of infection was accompanied by the formation of CP aggregates of increasing size. Genomic ssDNA was found in the cytoplasm and in the nucleus, while the dsDNA replicative form was exclusively associated with the nucleus. CP-DNA complexes were detected by immuno-capture PCR in nuclear and cytoplasmic large aggregates. Nuclear aggregates contained infectious particles transmissible to test plants by whiteflies. In contrast to susceptible tomatoes, the formation of large CP aggregates in resistant plants was delayed. By experimentally changing the level of resistance/susceptibility of plants, we showed that maintenance of midsized CP aggregates was associated with resistance, while large aggregates where characteristic of susceptibility. We propose that sequestering of virus CP into midsized aggregates and retarding the formation of large insoluble aggregates containing infectious particles is part of the response of resistant plants to TYLCV. PMID:23099086

  6. Experience of changing between signal and Bactec 9240 blood culture systems in a children's hospital.

    PubMed Central

    Gray, J; Brockwell, M; Das, I

    1998-01-01

    AIM: To compare experience of positive blood cultures in successive years before and after changing from Signal (Unipath) to Bactec 9240 (Becton Dickinson) blood culture systems. METHODS: Analysis of data collected prospectively on 7967 Signal and 7062 Bactec blood culture sets. RESULTS: Significant growths occurred in 5.7% of Signal and 8.9% of Bactec cultures; 33.0% more significant isolates and 24.0% more episodes of bacteraemia were detected in the second year, following introduction of the Bactec system. Inpatient hospital activity increased by 8.2% between the first and second years, although the numbers of blood cultures received actually fell by 11.4%. There were striking increases in numbers of isolates of coagulase negative staphylococci (47.7%) and Enterobacteriaceae (56.8%) from Bactec cultures. Two anaerobic bacteraemias were detected in Signal blood cultures, whereas none was detected by the Bactec system, despite 12.1% of sets including an anaerobic bottle. Of significant positive cultures, 90.2% were detected within one day with the Bactec 9240, compared with only 50.0% of Signal cultures; 20.7% of significant positive Signal blood cultures were detected only on terminal subculture. Microorganisms that were not significant were isolated from 5.1% Signal and 3.8% Bactec cultures. CONCLUSIONS: Compared with the Signal system, the Bactec 9240 offers markedly more rapid and sensitive detection of bacteraemia, together with a lower rate of non-significant isolates. However, using a single PEDS PLUS/F bottle the few episodes of anaerobic bacteraemia that occur in children are likely to be missed. PMID:9659243

  7. Organoid culture systems for prostate epithelial and cancer tissue.

    PubMed

    Drost, Jarno; Karthaus, Wouter R; Gao, Dong; Driehuis, Else; Sawyers, Charles L; Chen, Yu; Clevers, Hans

    2016-02-01

    This protocol describes a strategy for the generation of 3D prostate organoid cultures from healthy mouse and human prostate cells (either bulk or FACS-sorted single luminal and basal cells), metastatic prostate cancer lesions and circulating tumor cells. Organoids derived from healthy material contain the differentiated luminal and basal cell types, whereas organoids derived from prostate cancer tissue mimic the histology of the tumor. We explain how to establish these cultures in the fully defined serum-free conditioned medium that is required to sustain organoid growth. Starting with the plating of digested tissue material, full-grown organoids can usually be obtained in ∼2 weeks. The culture protocol we describe here is currently the only one that allows the growth of both the luminal and basal prostatic epithelial lineages, as well as the growth of advanced prostate cancers. Organoids established using this protocol can be used to study many different aspects of prostate biology, including homeostasis, tumorigenesis and drug discovery.

  8. Revisiting the Role of Cultural Capital in East Asian Educational Systems: The Case of South Korea

    PubMed Central

    Byun, Soo-yong; Schofer, Evan; Kim, Kyung-keun

    2013-01-01

    The concept of cultural capital has proved invaluable in understanding educational systems in Western countries, and recent work seeks to extend those insights to the diverse educational systems of other geographic regions. We explored cultural capital in South Korea by investigating the relationships among family socioeconomic status (SES), cultural capital, and children's academic achievement using data from the 2000 Programme for International Student Assessment. South Korea was compared with Japan, France, and the United States to understand how institutional features of South Korean education shape the role of cultural capital in academic success. Results showed that family SES had a positive effect on both parental objectified cultural capital and children's embodied cultural capital in South Korea, consistent with evidence from the other countries. Moreover, parental objectified cultural capital had a positive effect on children's academic achievement in South Korea. In contrast to other countries, however, children's embodied cultural capital had a negative effect on academic achievement in South Korea controlling for the other variables. We highlighted several institutional features of South Korean education including a standardized curriculum, extreme focus on test preparation, and extensive shadow education, which may combine to suppress the effect of children's embodied cultural capital on academic achievement. PMID:24285909

  9. Effect of cultural system and essential oil treatment on antioxidant capacity in raspberries.

    PubMed

    Jin, Peng; Wang, Shiow Y; Gao, Haiyan; Chen, Hangjun; Zheng, Yonghua; Wang, Chien Y

    2012-05-01

    The effects of cultural system and essential oil treatment on antioxidant capacities in raspberries were evaluated. Raspberries were hand-harvested from organic and conventional farms in Maryland, USA, and were treated with essential oil including carvacrol, anethole, cinnamic acid, perillaldehyde, cinnamaldehyde, and linalool. Results from this study showed that raspberries grown from organic culture exhibited higher value of antioxidant capacities and individual flavonoids contents. Moreover, the organic culture also enhanced the activities of antioxidant enzymes. In addition, essential oil treatments promoted the antioxidant enzymes activities and antioxidant capacities of raspberries, and the most effective compound was perillaldehyde. In conclusion, raspberries produced from organic culture contained significantly higher antioxidant capacities than those produce from conventional culture. Postharvest essential oil treatments have positive effect on enhancing antioxidant capacities in raspberries from both organic and conventional cultures.

  10. 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.

  11. 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.

  12. Aggregation Dynamics Using Phase Wave Signals and Branching Patterns

    NASA Astrophysics Data System (ADS)

    Sakaguchi, Hidetsugu; Kusagaki, Takuma

    2016-09-01

    The aggregation dynamics of slime mold is studied using coupled equations of phase ϕ and cell concentration n. Phase waves work as tactic signals for aggregation. Branching structures appear during the aggregation. A stationary branching pattern appears like a river network, if cells are uniformly supplied into the system.

  13. Proliferation and differentiation of mesenchymal stem cells in a three- dimensional culture system

    NASA Astrophysics Data System (ADS)

    Sun, S.; Hu, J.; Long, M.; Tao, Z.

    Mesenchymal stem cells (MSCs) have multi-differentiation potential and retain the capacity to proliferate and differentiate in vitro, which in turn holds the promise of being able to repair or replace damaged cells or tissues. Since MSCs are rare in amount in vivo, abundant cells usually need be obtained in time in clinic. T herefore, proliferation and differentiation of MSCs in vitro are necessary and important for future applications. Most current studies o MSCs are focused on the cellular andn molecular biology using a two-dimension (2-D) static culture system at unit gravity. The gravity-induced 2D culture of MSCs could potentially not reflect cell-cell- contacts important for proliferation and differentiation of MSCs in vivo. Here we developed a method to proliferate MSCs by using the rotating three-dimensional (3- D) culture system, which can provide low shear, 3-D environment with simulated microgravity. MSCs from human bone marrow were prepared on microcarrier beads and then were seeded in the 3-D culture system. Various rotation conditions were tested to screen out the most suitable one for proliferation of MSCs. 2-D cultures were prepared in routine cell culture dishes as a control. All cultures were uniformly inoculated and medium exchanged at standard intervals. Results were compared with microscopic and immunochemistrical techniques. The differentiation capacity of proliferated MSCs were also tested through induced differentiation experiments. It is found that simulated microgravity and three-dimensional culture condition is an active factor for proliferation of MSCs.

  14. Geographical information systems and bootstrap aggregation (bagging) of tree-based classifiers for Lyme disease risk prediction in Trentino, Italian Alps.

    PubMed

    Rizzoli, Annapaola; Merler, Stefano; Furlanello, Cesare; Genchi, Claudio

    2002-05-01

    The risk of exposure to Lyme disease in the province of Trento, Italian Alps, was predicted through the analysis of the distribution of Ixodes ricinus (L.) nymphs infected with Borrelia burgdorferi s.l. with a model based on bootstrap aggregation (bagging) of tree-based classifiers within a geographical information system (GIS). Data on L ricinus density assessed by dragging the vegetation in 438 sites during 1996 were cross-correlated with the digital cartography of a GIS, which included the variables altitude, exposure and slope, substratum, vegetation type and roe deer density. Ticks were more abundant at altitudes below 1,300 m a.s.l., in the presence of limestone and vegetation cover with thermophile deciduous forests and high densities of roe deer. A bootstrap aggregation procedure (bagging) was used to produce a model for the prediction of tick occurrence, the accuracy of which was tested on actual tick counts assessed by a further dragging campaign carried out during 1997 to determine infection prevalence and resulted in average 77%. Other tests of the model were made on additional and independent data sets. The prevalence of infection with Borrelia burgdorferi s.l, determined by polymerase chain reaction on 2,208 nymphs collected by random dragging in 245 transects selected within eight areas where the model predicted the occurrence of I. ricinus during 1997, was 17.5% and was positively correlated to tick abundance and roe deer density. These findings were used to relate the output of the bagged model (probability of tick occurrence) to the density of infected nymphs through a stepwise model selection procedure and thus to produce a GIS digital map of the probability distribution of infected nymphs in the Province of Trento at high resolution scale (50 by 50-m cell resolution). The application of the bagging procedure increased the accuracy of the prediction made by a single classification tree, a well-known classification method for the analysis of

  15. Geographical information systems and bootstrap aggregation (bagging) of tree-based classifiers for Lyme disease risk prediction in Trentino, Italian Alps.

    PubMed

    Rizzoli, Annapaola; Merler, Stefano; Furlanello, Cesare; Genchi, Claudio

    2002-05-01

    The risk of exposure to Lyme disease in the province of Trento, Italian Alps, was predicted through the analysis of the distribution of Ixodes ricinus (L.) nymphs infected with Borrelia burgdorferi s.l. with a model based on bootstrap aggregation (bagging) of tree-based classifiers within a geographical information system (GIS). Data on L ricinus density assessed by dragging the vegetation in 438 sites during 1996 were cross-correlated with the digital cartography of a GIS, which included the variables altitude, exposure and slope, substratum, vegetation type and roe deer density. Ticks were more abundant at altitudes below 1,300 m a.s.l., in the presence of limestone and vegetation cover with thermophile deciduous forests and high densities of roe deer. A bootstrap aggregation procedure (bagging) was used to produce a model for the prediction of tick occurrence, the accuracy of which was tested on actual tick counts assessed by a further dragging campaign carried out during 1997 to determine infection prevalence and resulted in average 77%. Other tests of the model were made on additional and independent data sets. The prevalence of infection with Borrelia burgdorferi s.l, determined by polymerase chain reaction on 2,208 nymphs collected by random dragging in 245 transects selected within eight areas where the model predicted the occurrence of I. ricinus during 1997, was 17.5% and was positively correlated to tick abundance and roe deer density. These findings were used to relate the output of the bagged model (probability of tick occurrence) to the density of infected nymphs through a stepwise model selection procedure and thus to produce a GIS digital map of the probability distribution of infected nymphs in the Province of Trento at high resolution scale (50 by 50-m cell resolution). The application of the bagging procedure increased the accuracy of the prediction made by a single classification tree, a well-known classification method for the analysis of

  16. Medical Devices; Obstetrical and Gynecological Devices; Classification of the Intravaginal Culture System. Final order.

    PubMed

    2016-01-01

    The Food and Drug Administration (FDA) is classifying the intravaginal culture system into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the intravaginal culture system's classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device. PMID:26742184

  17. The Role of State Early Childhood Comprehensive Systems in Promoting Cultural Competence and Effective Cross-Cultural Communication. Building State Early Childhood Comprehensive Systems Series, Number 8

    ERIC Educational Resources Information Center

    Sareen, Harvinder; Visencio, Diane; Russ, Shirley; Halfon, Neal

    2005-01-01

    If early childhood systems are to be effective at the population level then they must be able to provide family-centered care to all the racial, ethnic and cultural groups that they serve. Despite major policy driven and technological advances in healthcare, health disparities across different races and ethnicities persist. For example, the infant…

  18. 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.

  19. [Effects of different culture system of isolating and passage of sheep embryonic stem-like cells].

    PubMed

    Bai, Changming; Liu, Chousheng; Wang, Zhigang; Wang, Xinzhuang

    2008-07-01

    In this research, we use mouse embryonic fibroblasts as feeder layers. To eliminate the influence of serum and mouse embryonic stem cells (ESCs) conditioned medium (ESCCM) on self-renewal of sheep embryonic stem-like cells, knockout serum replacement (KSR) was used to replace serum, then supplanted with ESCCM for the isolation and cloning of sheep embryonic stem-like cells. We found when inner cell masses (ICMs) cultured in the control group with medium supplanted with fetal bovine serum (FBS), sheep ES-like cells could not survive for more than 3 passages. However, sheep embryonic stem-like cells could remain undifferentiated for 5 passages when cultured in the medium that FBS was substituted by KSR. The result indicates that KSR culture system was more suitable for the isolation and cloning of sheep embryonic stem-like cells compared to FBS culture system. Finally we applied medium with 15% KSR as basic medium supplanted with 40% ESCCM as a new culture system to isolate sheep embryonic stem-like cells, we found one embryonic stem-like cell line still maintained undifferentiating for 8 passages, which characterized with a normal and stable karyotype and high expression of alkaline phosphatase. These results suggest that it is suitable to culture sheep ICM in the new culture system with 15% KSR as basic medium and supplanted with 40% ESCCM, which indicated that mouse ES cells might secrete factors playing important roles in promoting sheep ES-like cells' self-renewal. PMID:18837407

  20. [Effects of different culture system of isolating and passage of sheep embryonic stem-like cells].

    PubMed

    Bai, Changming; Liu, Chousheng; Wang, Zhigang; Wang, Xinzhuang

    2008-07-01

    In this research, we use mouse embryonic fibroblasts as feeder layers. To eliminate the influence of serum and mouse embryonic stem cells (ESCs) conditioned medium (ESCCM) on self-renewal of sheep embryonic stem-like cells, knockout serum replacement (KSR) was used to replace serum, then supplanted with ESCCM for the isolation and cloning of sheep embryonic stem-like cells. We found when inner cell masses (ICMs) cultured in the control group with medium supplanted with fetal bovine serum (FBS), sheep ES-like cells could not survive for more than 3 passages. However, sheep embryonic stem-like cells could remain undifferentiated for 5 passages when cultured in the medium that FBS was substituted by KSR. The result indicates that KSR culture system was more suitable for the isolation and cloning of sheep embryonic stem-like cells compared to FBS culture system. Finally we applied medium with 15% KSR as basic medium supplanted with 40% ESCCM as a new culture system to isolate sheep embryonic stem-like cells, we found one embryonic stem-like cell line still maintained undifferentiating for 8 passages, which characterized with a normal and stable karyotype and high expression of alkaline phosphatase. These results suggest that it is suitable to culture sheep ICM in the new culture system with 15% KSR as basic medium and supplanted with 40% ESCCM, which indicated that mouse ES cells might secrete factors playing important roles in promoting sheep ES-like cells' self-renewal.

  1. Manufacture of biopharmaceutical proteins by mammalian cell culture systems.

    PubMed

    Tolbert, W R

    1990-01-01

    In the last several years, dramatic advances have been in the development of new biopharmaceuticals including monoclonal antibodies for diagnosis and treatment and such genetically engineered proteins as tPA, Factor VIIIc, erythropoietin and soluble CD4, an anti-AIDS protein. Currently, there are several hundred such candidate drugs in human clinical trials. In most cases, these protein-based drugs will require manufacture by mammalian cell culture due to the inability of lower organisms to properly glycosylate, fold, make correct disulfide bonds and secrete active biomolecular forms. The need for large scale production from cell culture will greatly increase as more of the products in clinical trials are approved for commercial production. This will require significant reduction in manufacturing costs per gram, concomitant with increased capacity to hundreds or perhaps even thousands of kilograms annually. As an example, Invitron's multi-reactor manufacturing facility has operated at greater than one-half million liters per year and has experience with more than 250 mammalian cell lines for producing protein drug products.

  2. Lysine hydroxylation of collagen in a fibroblast cell culture system

    NASA Technical Reports Server (NTRS)

    Uzawa, Katsuhiro; Yeowell, Heather N.; Yamamoto, Kazushi; Mochida, Yoshiyuki; Tanzawa, Hideki; Yamauchi, Mitsuo

    2003-01-01

    The lysine (Lys) hydroxylation pattern of type I collagen produced by human fibroblasts in culture was analyzed and compared. Fibroblasts were cultured from normal human skin (NSF), keloid (KDF), fetal skin (FDF), and skin tissues of Ehlers-Danlos syndrome type VIA and VIB patients (EDS-VIA and -VIB). The type I collagen alpha chains with or without non-helical telopeptides were purified from the insoluble matrix and analyzed. In comparison with NSFs, KDF and FDF showed significantly higher Lys hydroxylation, particularly in the telopeptide domains of both alpha chains. Both EDS-VIA and -VIB showed markedly lower Lys hydroxylation in the helical domains of both alpha chains whereas that in the telopeptides was comparable with those of NSFs. A similar profile was observed in the tissue sample of the EDS-VIB patient. These results demonstrate that the Lys hydroxylation pattern is domain-specific within the collagen molecule and that this method is useful to characterize the cell phenotypes in normal/pathological connective tissues.

  3. Control of galactosylated glycoforms distribution in cell culture system.

    PubMed

    McCracken, Neil A; Kowle, Ronald; Ouyang, Anli

    2014-01-01

    Cell culture process conditions including media components and bioreactor operation conditions have a profound impact on recombinant protein quality attributes. Considerable changes in the distribution of galactosylated glycoforms (G0F, G1F, and G2F) were observed across multiple CHO derived recombinant proteins in development at Eli Lilly and Company when switching to a new chemically defined (CD) media platform condition. In the new CD platform, significantly lower G0F percentages and higher G1F and G2F were observed. These changes were of interest as glycosylation heterogeneity can impact the effectiveness of a protein. A systematic investigation was done to understand the root cause of the change and control strategy for galactosylated glycoforms distribution. It was found that changes in asparagine concentration could result in a corresponding change in G0F, G1F, and G2F distribution. A follow-up study examined a wider range of asparagine concentration and it was found that G0F, G1F, and G2F percentage could be titrated by adjusting asparagine concentration. The observed changes in heterogeneity from changing asparagine concentration are due to resulting changes in ammonium metabolism. Further study ascertained that different integrated ammonium level during the cell culture process could control G0F, G1F, and G2F percentage distribution. A mechanism hypothesis is proposed that integrated ammonium level impacts intracellular pH, which further regulates β-1, 4 galactosyltransferase activity. PMID:24692242

  4. D18G transthyretin is monomeric, aggregation prone, and not detectable in plasma and cerebrospinal fluid: a prescription for central nervous system amyloidosis?

    PubMed

    Hammarström, Per; Sekijima, Yoshiki; White, Joleen T; Wiseman, R Luke; Lim, Amareth; Costello, Catherine E; Altland, Klaus; Garzuly, Ferenc; Budka, Herbert; Kelly, Jeffery W

    2003-06-10

    Over 70 transthyretin (TTR) mutations facilitate amyloidosis in tissues other than the central nervous system (CNS). In contrast, the D18G TTR mutation in individuals of Hungarian descent leads to CNS amyloidosis. D18G forms inclusion bodies in Escherichia coli, unlike the other disease-associated TTR variants overexpressed to date. Denaturation and reconstitution of D18G from inclusion bodies afford a folded monomer that is destabilized by 3.1 kcal/mol relative to an engineered monomeric version of WT TTR. Since TTR tetramer dissociation is typically rate limiting for amyloid formation, the monomeric nature of D18G renders its amyloid formation rate 1000-fold faster than WT. It is perplexing that D18G does not lead to severe early onset systemic amyloidosis, given that it is the most destabilized TTR variant characterized to date, more so than variants exhibiting onset in the second decade. Instead, CNS impairment is observed in the fifth decade as the sole pathological manifestation; however, benign systemic deposition is also observed. Analysis of heterozygote D18G patient's serum and cerebrospinal fluid (CSF) detects only WT TTR, indicating that D18G is either rapidly degraded postsecretion or degraded within the cell prior to secretion, consistent with its inability to form hybrid tetramers with WT TTR. The nondetectable levels of D18G TTR in human plasma explain the absence of an early onset systemic disease. CNS disease may result owing to the sensitivity of the CNS to lower levels of D18G aggregate. Alternatively, or in addition, we speculate that a fraction of D18G made by the choroid plexus can be transiently tetramerized by the locally high thyroxine (T(4)) concentration, chaperoning it out into the CSF where it undergoes dissociation and amyloidogenesis due to the low T(4) CSF concentration. Selected small molecule tetramer stabilizers can transform D18G from a monomeric aggregation-prone state to a nonamyloidogenic tetramer, which may prove to be a

  5. Development of practical investigation system for cultural properties based on a projector-camera system

    NASA Astrophysics Data System (ADS)

    Miyata, Kimiyoshi

    2009-01-01

    Huge number of historical materials and cultural properties in museums are investigated based on scientific and chemical analysis techniques, however these techniques require specific equipments with difficult operations. In this research, a practical investigation system is developed to provide convenient way for investigating color information in variety of materials as the first step of the investigation process. The system consists of a data projector and a digital camera, and the system is examined to detect metameric color area as an example of investigation purposes. In this research, the data projector has a role of illuminator to yield illuminant metamerism, and the camera takes sequential images under different illumination colors created by the projector. In the experiment, seven colors of illumination are created by the projector, then images are taken under each colored illumination. The Euclid distance in the RGB space between a predetermined reference pixel and test pixels is calculated in each of taken images. These distances are compared with thresholds determined by using a metamerism test chart. The proposed system was examined for the test charts and Japanese authentic wooden prints, and the experimental results showed that the system could offer convenience as the first investigation of the materials.

  6. Cells and Culture Systems Used to Model the Small Airway Epithelium.

    PubMed

    Bhowmick, Rudra; Gappa-Fahlenkamp, Heather

    2016-06-01

    The pulmonary epithelium is divided into upper, lower, and alveolar (or small) airway epithelia and acts as the mechanical and immunological barrier between the external environment and the underlying submucosa. Of these, the small airway epithelium is the principal area of gas exchange and has high immunological activity, making it a major area of cell biology, immunology, and pharmaceutical research. As animal models do not faithfully represent the human pulmonary system and ex vivo human lung samples have reliability and availability issues, cell lines, and primary cells are widely used as small airway epithelial models. In vitro, these cells are mostly cultured as monolayers (2-dimensional cultures), either media submerged or at air-liquid interface. However, these 2-dimensional cultures lack a three dimension-a scaffolding extracellular matrix, which establishes the intercellular network in the in vivo airway epithelium. Therefore, 3-dimensional cell culture is currently a major area of development, where cells are cultured in a matrix or are cultured in a manner that they develop ECM-like scaffolds between them, thus mimicking the in vivo phenotype more faithfully. This review focuses on the commonly used small airway epithelial cells, their 2-dimensional and 3-dimensional culture techniques, and their comparative phenotype when cultured under these systems. PMID:27071933

  7. Reconsidering the mechanism of polyglutamine peptide aggregation.

    PubMed

    Lee, Christine C; Walters, Robert H; Murphy, Regina M

    2007-11-01

    There are at least nine neurodegenerative diseases associated with proteins that contain an unusually expanded polyglutamine domain, the best known of which is Huntington's disease. In all of these diseases, the mutant protein aggregates into neuronal inclusions; it is generally, although not universally, believed that protein aggregation is an underlying cause of the observed neuronal degeneration. In an effort to examine the role of polyglutamine in facilitating protein aggregation, investigators have used synthetic polyglutamine peptides as model systems. Analysis of kinetic data led to the conclusions that aggregation follows a simple nucleation-elongation mechanism characterized by a significant lag time, during which the peptide is monomeric, and that the nucleus is a monomer in a thermodynamically unfavorable conformation [Chen, S. M., et al. (2002) Proc. Natl. Acad. Sci. U.S.A. 99, 11884-11889]. We re-examined this hypothesis by measuring the aggregation kinetics of the polyglutamine peptide K2Q23K2, using sedimentation, static and dynamic light scattering, and size exclusion chromatography. Our data show that during the lag time in sedimentation kinetics, there is substantial organization of the peptide into soluble linear aggregates. These aggregates have no regular secondary structure as measured by circular dichroism but have particle dimensions and morphologies similar to those of mature insoluble aggregates. The soluble aggregates constitute approximately 30% of the total peptide mass, form rapidly, and continue to grow over a period of hours to days, eventually precipitating. Once insoluble aggregates form, loss of monomer from the solution phase continues. Our data support an assembly mechanism for polyglutamine peptide more complex than that previously proposed.

  8. Classification and Characterization of Therapeutic Antibody Aggregates

    PubMed Central

    Joubert, Marisa K.; Luo, Quanzhou; Nashed-Samuel, Yasser; Wypych, Jette; Narhi, Linda O.

    2011-01-01

    A host of diverse stress techniques was applied to a monoclonal antibody (IgG2) to yield protein particles with varying attributes and morphologies. Aggregated solutions were evaluated for percent aggregation, particle counts, size distribution, morphology, changes in secondary and tertiary structure, surface hydrophobicity, metal content, and reversibility. Chemical modifications were also identified in a separate report (Luo, Q., Joubert, M. K., Stevenson, R., Narhi, L. O., and Wypych, J. (2011) J. Biol. Chem. 286, 25134–25144). Aggregates were categorized into seven discrete classes, based on the traits described. Several additional molecules (from the IgG1 and IgG2 subtypes as well as intravenous IgG) were stressed and found to be defined with the same classification system. The mechanism of protein aggregation and the type of aggregate formed depends on the nature of the stress applied. Different IgG molecules appear to aggregate by a similar mechanism under the same applied stress. Aggregates created by harsh mechanical stress showed the largest number of subvisible particles, and the class generated by thermal stress displayed the largest number of visible particles. Most classes showed a disruption of the higher order structure, with the degree of disorder depending on the stress process. Particles in all classes (except thermal stress) were at least partially reversible upon dilution in pH 5 buffer. High copper content was detected in isolated metal-catalyzed aggregates, a stress previously shown to produce immunogenic aggregates. In conclusion, protein aggregates can be a very heterogeneous population, whose qualities are the result of the type of stress that was experienced. PMID:21454532

  9. Evaluation of a new biphasic culture system for the recovery of mycobacteria.

    PubMed

    Giger, T; Burkardt, H J

    1990-06-01

    A newly developed biphasic culture system (MB-Check) for recovery of mycobacteria was evaluated. The biphasic system consists of a bottle containing selective modified Middlebrook 7H9 broth and a mounted dip slide with chocolate agar and modified Middlebrook 7H11 agar with and without NAP. The system was compared with culture on two egg-based media, Lowenstein medium and a selective Gottsacker medium, using 995 routine specimens and 90 artificially seeded sputa. Mycobacterium tuberculosis was detected in 17 of the 995 routine specimens by the biphasic system and in 14 specimens by the egg-based media together. In the artificially seeded sputa the biphasic system showed higher sensitivity in detection of both tuberculosis complex and non-tuberculous mycobacteria than the egg-based media. The recovery times of the new system were comparable to those of the two conventional culture methods. PMID:2387296

  10. Short report: Failure of Burkholderia pseudomallei to grow in an automated blood culture system.

    PubMed

    Teerawattanasook, Nittaya; Limmathurotsakul, Direk; Day, Nicholas P J; Wuthiekanun, Vanaporn

    2014-12-01

    We compared the organisms isolated from 30,210 pairs of blood culture bottles by using BacT/Alert system and the conventional system. Overall, 2,575 (8.5%) specimens were culture positive for pathogenic organisms. The sensitivity for detection of pathogenic organisms with the BACT/Alert system (85.6%, 2,203 of 2,575) was significantly higher than that with the conventional method (74.1%, 1,908 of 2,575; P < 0.0001). However, Burkholderia pseudomallei was isolated less often with the BacT/ALERT system (73.5%, 328 of 446) than with the conventional system (90.3%, 403 of 446; P < 0.0001). This finding suggests that use of the conventional culture method in conjunction with the BacT/Alert system may improve the isolation rate for B. pseudomallei in melioidosis-endemic areas.

  11. On the Embedded Complementarity of Agent-Based and Aggregate Reasoning in Students' Developing Understanding of Dynamic Systems

    ERIC Educational Resources Information Center

    Stroup, Walter M.; Wilensky, Uri

    2014-01-01

    Placed in the larger context of broadening the engagement with systems dynamics and complexity theory in school-aged learning and teaching, this paper is intended to introduce, situate, and illustrate--with results from the use of network supported participatory simulations in classrooms--a stance we call "embedded complementarity" as an…

  12. Three-dimensional chemotaxis-driven aggregation of tumor cells

    PubMed Central

    Puliafito, Alberto; De Simone, Alessandro; Seano, Giorgio; Gagliardi, Paolo Armando; Di Blasio, Laura; Chianale, Federica; Gamba, Andrea; Primo, Luca; Celani, Antonio

    2015-01-01

    One of the most important steps in tumor progression involves the transformation from a differentiated epithelial phenotype to an aggressive, highly motile phenotype, where tumor cells invade neighboring tissues. Invasion can occur either by isolated mesenchymal cells or by aggregates that migrate collectively and do not lose completely the epithelial phenotype. Here, we show that, in a three-dimensional cancer cell culture, collective migration of cells eventually leads to aggregation in large clusters. We present quantitative measurements of cluster velocity, coalescence rates, and proliferation rates. These results cannot be explained in terms of random aggregation. Instead, a model of chemotaxis-driven aggregation – mediated by a diffusible attractant – is able to capture several quantitative aspects of our results. Experimental assays of chemotaxis towards culture conditioned media confirm this hypothesis. Theoretical and numerical results further suggest an important role for chemotactic-driven aggregation in spreading and survival of tumor cells. PMID:26471876

  13. Blood culture examinations at a community hospital without a microbiology laboratory: using an automated blood culture system and performing a Gram stain on positive culture bottles in the institution.

    PubMed

    Saito, Takashi; Aoki, Yoji; Mori, Yoshihiro; Kohi, Fumikazu

    2004-08-01

    To elucidate the existence of microorganisms from blood culture bottles in hospitals without a microbiology laboratory, we changed the system of blood culture examinations. The Oxoid signal blood culture system and submission of all blood cultures to the clinical testing industry was used from July 2002 to December 2002 (first period). Use of the BacT/Alert system and performing of Gram stain for positive culture bottles in our institutions was conducted from January 2003 to June 2003 (latter period). A total of 210 and 193 blood cultures were processed during the first and latter periods, respectively. There were 40 (19.0%) positive cultures in the first period and 32 (16.6%) positive cultures in the latter period. The times from the specimen collection to the Gram stain result that were required were 3.8 and 1.0 days in the first period and the latter period, respectively. The times required for the final report of the blood cultures in the first period and in the latter period were 5.8 and 4.9 days, respectively. We conclude that using a continuous monitoring, automated blood culture system and performing Gram stain for positive culture bottles in institutions without microbiology laboratories may be useful for medical doctors to rapidly determine the existence of microorganisms and to begin adequate antiinfective therapy.

  14. Spatially monitoring oxygen level in 3D microfabricated cell culture systems using optical oxygen sensing beads.

    PubMed

    Wang, Lin; Acosta, Miguel A; Leach, Jennie B; Carrier, Rebecca L

    2013-04-21

    Capability of measuring and monitoring local oxygen concentration at the single cell level (tens of microns scale) is often desirable but difficult to achieve in cell culture. In this study, biocompatible oxygen sensing beads were prepared and tested for their potential for real-time monitoring and mapping of local oxygen concentration in 3D micro-patterned cell culture systems. Each oxygen sensing bead is composed of a silica core loaded with both an oxygen sensitive Ru(Ph2phen3)Cl2 dye and oxygen insensitive Nile blue reference dye, and a poly-dimethylsiloxane (PDMS) shell rendering biocompatibility. Human intestinal epithelial Caco-2 cells were cultivated on a series of PDMS and type I collagen based substrates patterned with micro-well arrays for 3 or 7 days, and then brought into contact with oxygen sensing beads. Using an image analysis algorithm to convert florescence intensity of beads to partial oxygen pressure in the culture system, tens of microns-size oxygen sensing beads enabled the spatial measurement of local oxygen concentration in the microfabricated system. Results generally indicated lower oxygen level inside wells than on top of wells, and local oxygen level dependence on structural features of cell culture surfaces. Interestingly, chemical composition of cell culture substrates also appeared to affect oxygen level, with type-I collagen based cell culture systems having lower oxygen concentration compared to PDMS based cell culture systems. In general, results suggest that oxygen sensing beads can be utilized to achieve real-time and local monitoring of micro-environment oxygen level in 3D microfabricated cell culture systems.

  15. Generation of Microtumors Using 3D Human Biogel Culture System and Patient-derived Glioblastoma Cells for Kinomic Profiling and Drug Response Testing.

    PubMed

    Gilbert, Ashley N; Shevin, Rachael S; Anderson, Joshua C; Langford, Catherine P; Eustace, Nicholas; Gillespie, G Yancey; Singh, Raj; Willey, Christopher D

    2016-01-01

    The use of patient-derived xenografts for modeling cancers has provided important insight into cancer biology and drug responsiveness. However, they are time consuming, expensive, and labor intensive. To overcome these obstacles, many research groups have turned to spheroid cultures of cancer cells. While useful, tumor spheroids or aggregates do not replicate cell-matrix interactions as found in vivo. As such, three-dimensional (3D) culture approaches utilizing an extracellular matrix scaffold provide a more realistic model system for investigation. Starting from subcutaneous or intracranial xenografts, tumor tissue is dissociated into a single cell suspension akin to cancer stem cell neurospheres. These cells are then embedded into a human-derived extracellular matrix, 3D human biogel, to generate a large number of microtumors. Interestingly, microtumors can be cultured for about a month with high viability and can be used for drug response testing using standard cytotoxicity assays such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and live cell imaging using Calcein-AM. Moreover, they can be analyzed via immunohistochemistry or harvested for molecular profiling, such as array-based high-throughput kinomic profiling, which is detailed here as well. 3D microtumors, thus, represent a versatile high-throughput model system that can more closely replicate in vivo tumor biology than traditional approaches. PMID:27341166

  16. Pathway Aggregation in the Risk Assessment of Proliferation Resistance and Physical Protection (PR&PP) of Nuclear Energy Systems

    SciTech Connect

    Aldemir, Tunc; Denning, Richard; Catalyurek, Umit; Yilmaz, Alper; Yue, Meng; Cheng, Lap-Yan

    2015-01-23

    The framework for Proliferation Resistance and Physical Protection (PR & PP) evaluation is to define a set of challenges, to obtain the system responses, and to assess the outcomes. The assessment of outcomes heavily relies on pathways, defined as sequences of events or actions that could potentially be followed by a State or a group of individuals in order to achieve a proliferation objective, with the defined threats as initiating events. There may be large number of segments connecting pathway stages (e.g. acquisition, processing, and fabrication for PR) which can lead to even larger number of pathways or scenarios through possible different combinations of segment connections, each with associated probabilities contributing to the overall risk. Clustering of these scenarios in specified stage attribute intervals is important for their tractable analysis and outcome assessment. A software tool for scenario generation and clustering (OSUPR) is developed that utilizes the PRCALC code developed at the Brookhaven National Laboratory for scenario generation and the K- means, mean shift and adaptive mean shift algorithms as possible clustering schemes. The results of the study using the Example Sodium Fast Breeder as an example system show that clustering facilitates the probabilistic or deterministic analysis of scenarios to identify system vulnerabilities and communication of the major risk contributors to stakeholders. The results of the study also show that the mean shift algorithm has the most potential for assisting the analysis of the scenarios generated by PRCALC.

  17. Engineering a Fibrocartilage Spectrum Through Modulation of Aggregate Redifferentiation

    PubMed Central

    Murphy, Meghan K.; Masters, Taylor E.; Hu, Jerry C.; Athanasiou, Kyriacos A.

    2015-01-01

    Expanded costochondral cells provide a clinically relevant cell source for engineering both fibrous and hyaline articular cartilage. Expanding chondrocytes in monolayer results in a shift toward a proliferative, fibroblastic phenotype. Three-dimensional aggregate culture may, however, be used to recover chondrogenic matrix production. This study sought to engineer a spectrum of fibrous to hyaline neocartilage from a single cell source by varying the duration of three-dimensional culture following expansion. In third passage porcine costochondral cells, the effects of aggregate culture duration were assessed after 0, 8, 11, 14, and 21 days of aggregate culture and after 4 subsequent weeks of neocartilage formation. Varying the duration of aggregate redifferentiation generated a spectrum of fibrous to hyaline neocartilage. Within 8 days of aggregation, proliferation ceased, and collagen and glycosaminoglycan production increased, compared with monolayer cells. In self-assembled neocartilage, type II to I collagen ratio increased with increasing aggregate duration, yet glycosaminoglycan content varied minimally. Notably, 14 days of aggregate redifferentiation increased collagen content by 25%, tensile modulus by over 110%, and compressive moduli by over 50%, compared with tissue formed in the absence of redifferentiation. A spectrum of fibrous to hyaline cartilage was generated using a single, clinically relevant cell source, improving the translational potential of engineered cartilage. PMID:24380383

  18. Investigating Educational Systems, Leadership, and School Culture: A Holistic Approach

    ERIC Educational Resources Information Center

    Pratt, Jill Elizabeth

    2014-01-01

    Most populous school districts operate using a bureaucratic hierarchical organizational structure developed primarily for industry, a system structure that has remained intact for a century despite evolving from a manufacturing to a knowledge-based economy. Although strong for efficiency, this system structure is resistant to change and promotes…

  19. Dynamics of proteins aggregation. I. Universal scaling in unbounded media

    NASA Astrophysics Data System (ADS)

    Zheng, Size; Javidpour, Leili; Shing, Katherine S.; Sahimi, Muhammad

    2016-10-01

    It is well understood that in some cases proteins do not fold correctly and, depending on their environment, even properly-folded proteins change their conformation spontaneously, taking on a misfolded state that leads to protein aggregation and formation of large aggregates. An important factor that contributes to the aggregation is the interactions between the misfolded proteins. Depending on the aggregation environment, the aggregates may take on various shapes forming larger structures, such as protein plaques that are often toxic. Their deposition in tissues is a major contributing factor to many neuro-degenerative diseases, such as Alzheimer's, Parkinson's, amyotrophic lateral sclerosis, and prion. This paper represents the first part in a series devoted to molecular simulation of protein aggregation. We use the PRIME, a meso-scale model of proteins, together with extensive discontinuous molecular dynamics simulation to study the aggregation process in an unbounded fluid system, as the first step toward MD simulation of the same phenomenon in crowded cellular environments. Various properties of the aggregates have been computed, including dynamic evolution of aggregate-size distribution, mean aggregate size, number of peptides that contribute to the formation of β sheets, number of various types of hydrogen bonds formed in the system, radius of gyration of the aggregates, and the aggregates' diffusivity. We show that many of such quantities follow dynamic scaling, similar to those for aggregation of colloidal clusters. In particular, at long times the mean aggregate size S(t) grows with time as, S(t) ˜ tz, where z is the dynamic exponent. To our knowledge, this is the first time that the qualitative similarity between aggregation of proteins and colloidal aggregates has been pointed out.

  20. Supramolecular energy transfer from photoexcited chlorosomal zinc porphyrin self-aggregates to a chlorin or bacteriochlorin monomer as models of main light-harvesting antenna systems in green photosynthetic bacteria.

    PubMed

    Kataoka, Yumiko; Shibata, Yutaka; Tamiaki, Hitoshi

    2012-08-15

    Self-aggregates of a synthetic zinc porphyrin worked as a light absorber and photoexcited energy donor, transferred the collected energy to a small amount of 3-acetyl-(bacterio)chlorin monomer, and induced near-infrared fluorescence from the acceptors in aqueous micellar solution. These artificial supramolecular systems are novel models of the main light-harvesting antennas of green photosynthetic bacteria, chlorosomes.

  1. Tissue culture system using a PANDA ring resonator and wavelength router for hydroponic plant.

    PubMed

    Kamoldilok, Surachart; Suwanpayak, Nathaporn; Suttirak, Saisudawan; Yupapin, Preecha P

    2012-06-01

    A novel system of nanofluidics trapping and delivery, which is known as a tissue culture system is proposed. By using the intense optical pulse(i.e., a soliton pulse) and a system constructed by a liquid core waveguide, the optical vortices (gradient optical fields/wells) can be generated, where the trapping tools in the same way as the optical tweezers in the PANDA ring resonator can be formed. By controlling the suitable parameters, the intense optical vortices can be generated within the PANDA ring resonator, in which the nanofluidics can be trapped and moved (transported) dynamically within the Tissue culture system(a wavelength router), which can be used for tissue culture and delivery in the hydroponic plant system.

  2. Aggregation of organic matter by pelagic tunicates

    SciTech Connect

    Pomeroy, L.R.; Deibel, D.

    1980-07-01

    Three genera of pelagic tunicates were fed concentrates of natural seston and an axenic diatom culture. Fresh and up to 4-day-old feces resemble flocculent organic aggregates containing populations of microorganisms, as described from highly productive parts of the ocean, and older feces resemble the nearly sterile flocculent aggregates which are ubiquitous in surface waters. Fresh feces consist of partially digested phytoplankton and other inclusions in an amorphous gelatinous matrix. After 18 to 36 h, a population of large bacteria develops in the matrix and in some of the remains of phytoplankton contained in the feces. From 48 to 96 h, protozoan populations arise which consume the bacteria and sometimes the remains of the phytoplankton in the feces. Thereafter only a sparse population of microorganisms remains, and the particles begin to fragment. Water samples taken in or below dense populations of salps and doliolids contained greater numbers of flocculent aggregates than did samples from adjacent stations.

  3. Self-driven perfusion culture system using a paper-based double-layered scaffold.

    PubMed

    Ozaki, Ai; Arisaka, Yoshinori; Takeda, Naoya

    2016-01-01

    Shear stress caused by fluid flow is known to promote tissue development from cells in vivo. Therefore, perfusion cultures have been studied to investigate the mechanisms involved and to fabricate engineered tissues in vitro, particularly those that include blood vessels. Microfluidic devices, which function with fine machinery of chambers and microsyringes for fluid flow and have small culture areas, are conventionally used for perfusion culture. In contrast, we have developed a self-driven perfusion culture system by using a paper-based double-layered scaffold as the fundamental component. Gelatin microfibers were electrospun onto a paper material to prepare the scaffold system, in which the constant perfusion of the medium and the scaffold for cell adhesion/proliferation were functionally divided into a paper and a gelatin microfiber layer, respectively. By applying both the capillary action and siphon phenomenon of the paper-based scaffold, which bridged two medium chambers at different height levels, a self-driven medium flow was achieved and the flow rate was also stable, constant, and quantitatively controllable. Moreover, the culture area was enlargeable to the cm(2) scale. The endothelial cells cultivated on this system oriented along the medium-flow direction, suggesting that the shear stress caused by medium flow was effectively applied. This perfusion culture system is expected to be useful for fabricating three-dimensional and large engineered tissues in the future. PMID:27550929

  4. Glycoprotein secretion in a tracheal organ culture system

    SciTech Connect

    Warunek, D.J.

    1985-01-01

    Glycoprotein secretion in the rat trachea was studied in vitro, utilizing a modified, matrix embed/perfusion chamber. Baseline parameters of the culture environment were determined by enzymatic and biochemical procedures. The effect of pilocarpine on the release of labelled glycoproteins from the tracheal epithelium was assessed. After a single stimulation with the drug, there was a significant increase in the release of /sup 14/C-glucosamine and /sup 3/H-fucose-labelled glycoprotein. The response was dose-dependent. Similar results were obtained after a second exposure to pilocarpine. However, no dose response was observed. Morphological analyses of the tracheal epithelial secretory cells by Alcian Blue/Periodic Acid Schiff staining showed a significant decrease in the total number of Alcian Blue staining cells and an increase in the mixed cell population after a single exposure to pilocarpine. Second stimulation with the drug showed that the trachea was able to respond again, this time with a further decrease in the number of Alcian Blue staining cells and a decrease in the PAS staining cells as well. Carbohydrate analyses after the first simulation with pilocarpine showed increased levels of N-acetyl neuraminic acid and the neutral carbohydrates, fucose and galactose, in the precipitated glycoproteins.

  5. Mixed culture polyhydroxyalkanoates production from sugar molasses: the use of a 2-stage CSTR system for culture selection.

    PubMed

    Albuquerque, M G E; Concas, S; Bengtsson, S; Reis, M A M

    2010-09-01

    Polyhydroxyalkanoates (PHAs) are promising biodegradable polymers. The use of mixed microbial cultures (MMC) and low cost feedstocks have a positive impact on the cost-effectiveness of the process. It has typically been carried out in Sequencing Batch Reactors (SBR). In this study, a 2-stage CSTR system (under Feast and Famine conditions) was used to effectively select for PHA-storing organisms using fermented molasses as feedstock. The effect of influent substrate concentration (60-120 Cmmol VFA/L) and HRT ratio between the reactors (0.2-0.5h/h) on the system's selection efficiency was assessed. It was shown that Feast reactor residual substrate concentration impacted on the selective pressure for PHA storage (due to substrate-dependent kinetic limitation). Moreover, a residual substrate concentration coming from the Feast to the Famine reactor did not jeopardize the physiological adaptation required for enhanced PHA storage. The culture reached a maximum PHA content of 61%. This success opens new perspectives to the use of wastewater treatment infrastructure for PHA production, thus valorizing either excess sludge or wastewaters.

  6. In Vivo Bone Regeneration Using Tubular Perfusion System Bioreactor Cultured Nanofibrous Scaffolds

    PubMed Central

    Yeatts, Andrew B.; Both, Sanne K.; Yang, Wanxun; Alghamdi, Hamdan S.; Yang, Fang; Jansen, John A.

    2014-01-01

    The use of bioreactors for the in vitro culture of constructs for bone tissue engineering has become prevalent as these systems may improve the growth and differentiation of a cultured cell population. Here we utilize a tubular perfusion system (TPS) bioreactor for the in vitro culture of human mesenchymal stem cells (hMSCs) and implant the cultured constructs into rat femoral condyle defects. Using nanofibrous electrospun poly(lactic-co-glycolic acid)/poly(ɛ-caprolactone) scaffolds, hMSCs were cultured for 10 days in vitro in the TPS bioreactor with cellular and acellular scaffolds cultured statically for 10 days as a control. After 3 and 6 weeks of in vivo culture, explants were removed and subjected to histomorphometric analysis. Results indicated more rapid bone regeneration in defects implanted with bioreactor cultured scaffolds with a new bone area of 1.23±0.35 mm2 at 21 days compared to 0.99±0.43 mm2 and 0.50±0.29 mm2 in defects implanted with statically cultured scaffolds and acellular scaffolds, respectively. At the 21 day timepoint, statistical differences (p<0.05) were only observed between defects implanted with cell containing scaffolds and the acellular control. After 42 days, however, defects implanted with TPS cultured scaffolds had the greatest new bone area with 1.72±0.40 mm2. Defects implanted with statically cultured and acellular scaffolds had a new bone area of 1.26±0.43 mm2 and 1.19±0.33 mm2, respectively. The increase in bone growth observed in defects implanted with TPS cultured scaffolds was statistically significant (p<0.05) when compared to both the static and acellular groups at this timepoint. This study demonstrates the efficacy of the TPS bioreactor to improve bone tissue regeneration and highlights the benefits of utilizing perfusion bioreactor systems to culture MSCs for bone tissue engineering. PMID:23865551

  7. Dysfunction of constitutive and inducible ubiquitin-proteasome system in amyotrophic lateral sclerosis: implication for protein aggregation and immune response.

    PubMed

    Bendotti, Caterina; Marino, Marianna; Cheroni, Cristina; Fontana, Elena; Crippa, Valeria; Poletti, Angelo; De Biasi, Silvia

    2012-05-01

    The ubiquitin-proteasome system (UPS) is the major intracellular proteolytic mechanism controlling the degradation of misfolded/abnormal proteins. A common hallmark in amyotrophic lateral sclerosis (ALS) and in other neurodegenerative disorders is the accumulation of misfolded/abnormal proteins into the damaged neurons, leading to the formation of cellular inclusions that are mostly ubiquitin-positive. Although proteolysis is a complex mechanism requiring the participation of different pathways, the abundant accumulation of ubiquitinated proteins strongly suggests an important contribution of UPS to these neuropathological features. The use of cellular and animal models of ALS, particularly those expressing mutant SOD1, the gene mutation most represented in familiar ALS, has provided significant evidence for a role of UPS in protein inclusions formation and motor neuron death. This review will specifically discuss this piece of evidence and provide suggestions of potential strategies for therapeutic intervention. We will also discuss the finding that, unlike the constitutive proteasome subunits, the inducible subunits are overexpressed early during disease progression in SOD1 mice models of ALS. These subunits form the immunoproteasome and generate peptides for the major histocompatibility complex class I molecules, suggesting a role of this system in the immune responses associated with the pathological features of ALS. Since recent discoveries indicate that innate and adaptive immunity may influence the disease process, in this review we will also provide evidence of a possible connection between immune-inflammatory reactions and UPS function, in the attempt to better understand the etiopathology of ALS and to identify appropriate targets for novel treatment strategies of this devastating disease. PMID:22033150

  8. Lab on a chip-based hepatic sinusoidal system simulator for optimal primary hepatocyte culture.

    PubMed

    Choi, Yoon Young; Kim, Jaehyung; Lee, Sang-Hoon; Kim, Dong-Sik

    2016-08-01

    Primary hepatocyte cultures have been used in studies on liver disease, physiology, and pharmacology. While they are an important tool for in vitro liver studies, maintaining liver-specific characteristics of hepatocytes in vitro is difficult, as these cells rapidly lose their unique characteristics and functions. Portal flow is an important condition to preserve primary hepatocyte functions and liver regeneration in vivo. We have developed a microfluidic chip that does not require bulky peripheral devices or an external power source to investigate the relationship between hepatocyte functional maintenance and flow rates. In our culture system, two types of microfluidic devices were used as scaffolds: a monolayer- and a concave chamber-based device. Under flow conditions, our chips improved albumin and urea secretion rates after 13 days compared to that of the static chips. Reverse transcription polymerase chain reaction demonstrated that hepatocyte-specific gene expression was significantly higher at 13 days under flow conditions than when using static chips. For both two-dimensional and three-dimensional culture on the chips, flow resulted in the best performance of the hepatocyte culture in vitro. We demonstrated that flow improves the viability and efficiency of long-term culture of primary hepatocytes and plays a key role in hepatocyte function. These results suggest that this flow system has the potential for long-term hepatocyte cultures as well as a technique for three-dimensional culture. PMID:27334878

  9. Magnetic field-magnetic nanoparticle culture system used to grow in vitro murine embryonic stem cells.

    PubMed

    de Freitas, Erika Regina Leal; Soares, Paula Roberta Otaviano; de Santos, Rachel Paula; dos Santos, Regiane Lopes; Porfírio, Elaine Paulucio; Báo, Sônia N; Lima, Emília Celma Oliveira; Guillo, Lídia Andreu

    2011-01-01

    The in vitro growth of embryonic stem cells (ESCs) is usually obtained in the presence of murine embryonic fibroblasts (MEF), but new methods for in vitro expansion of ESCs should be developed due to their potential clinical use. This study aims to establish a culture system to expand and maintain ESCs in the absence of MEF by using murine embryonic stem cells (mECS) as a model of embryonic stem cell. Magnetic nanoparticles (MNPs) were used for growing mESCs in the presence of an external magnetic field, creating the magnetic field-magnetic nanoparticle (MF-MNP) culture system. The growth characteristics were evaluated showing a doubling time slightly higher for mESCs cultivated in the presence of the system than in the presence of the MEF. The undifferentiated state was characterized by RT-PCR, immunofluorescence, alkaline phosphatase activity and electron microscopy. Murine embryonic stem cells cultivated in presence of the MF-MNP culture system exhibited Oct-4 and Nanog expression and high alkaline phosphatase activity. Ultrastructural morphology showed that the MF-MNP culture system did not interfere with processes that cause structural changes in the cytoplasm or nucleus. The MF-MNP culture system provides a tool for in vitro expansion of mESCs and could contribute to studies that aim the therapeutic use of embryonic stem cells. PMID:21446404

  10. System for measuring oxygen consumption rates of mammalian cells in static culture under hypoxic conditions.

    PubMed

    Kagawa, Yuki; Miyahara, Hirotaka; Ota, Yuri; Tsuneda, Satoshi

    2016-01-01

    Estimating the oxygen consumption rates (OCRs) of mammalian cells in hypoxic environments is essential for designing and developing a three-dimensional (3-D) cell culture system. However, OCR measurements under hypoxic conditions are infrequently reported in the literature. Here, we developed a system for measuring OCRs at low oxygen levels. The system injects nitrogen gas into the environment and measures the oxygen concentration by an optical oxygen microsensor that consumes no oxygen. The developed system was applied to HepG2 cells in static culture. Specifically, we measured the spatial profiles of the local dissolved oxygen concentration in the medium, then estimated the OCRs of the cells. The OCRs, and also the pericellular oxygen concentrations, decreased nonlinearly as the oxygen partial pressure in the environment decreased from 19% to 1%. The OCRs also depended on the culture period and the matrix used for coating the dish surface. Using this system, we can precisely estimate the OCRs of various cell types under environments that mimic 3-D culture conditions, contributing crucial data for an efficient 3-D culture system design. PMID:26558344

  11. Dynamic cell culture system: a new cell cultivation instrument for biological experiments in space

    NASA Technical Reports Server (NTRS)

    Gmunder, F. K.; Nordau, C. G.; Tschopp, A.; Huber, B.; Cogoli, A.

    1988-01-01

    The prototype of a miniaturized cell cultivation instrument for animal cell culture experiments aboard Spacelab is presented (Dynamic cell culture system: DCCS). The cell chamber is completely filled and has a working volume of 200 microliters. Medium exchange is achieved with a self-powered osmotic pump (flowrate 1 microliter h-1). The reservoir volume of culture medium is 230 microliters. The system is neither mechanically stirred nor equipped with sensors. Hamster kidney (Hak) cells growing on Cytodex 3 microcarriers were used to test the biological performance of the DCCS. Growth characteristics in the DCCS, as judged by maximal cell density, glucose consumption, lactic acid secretion and pH, were similar to those in cell culture tubes.

  12. Gibberellic acid production by free and immobilized cells in different culture systems.

    PubMed

    Durán-Páramo, Enrique; Molina-Jiménez, Héctor; Brito-Arias, Marco A; Robles-Martínez, Fabián

    2004-01-01

    Gibberellic acid production was studied in different fermentation systems. Free and immobilized cells of Gibberella fujikuroi cultures in shake-flask, stirred and fixed-bed reactors were evaluated for the production of gibberellic acid (GA3). Gibberellic acid production with free cells cultured in a stirred reactor reached 0.206 g/L and a yield of 0.078 g of GA3/g biomass.

  13. The fitness and functionality of culturally evolved communication systems.

    PubMed

    Fay, Nicolas; Garrod, Simon; Roberts, Leo

    2008-11-12

    This paper assesses whether human communication systems undergo the same progressive adaptation seen in animal communication systems and concrete artefacts. Four experiments compared the fitness of ad hoc sign systems created under different conditions when participants play a graphical communication task. Experiment 1 demonstrated that when participants are organized into interacting communities, a series of signs evolve that enhance individual learning and promote efficient decoding. No such benefits are found for signs that result from the local interactions of isolated pairs of interlocutors. Experiments 2 and 3 showed that the decoding benefits associated with community evolved signs cannot be attributed to superior sign encoding or detection. Experiment 4 revealed that naive overseers were better able to identify the meaning of community evolved signs when compared with isolated pair developed signs. Hence, the decoding benefits for community evolved signs arise from their greater residual iconicity. We argue that community evolved sign systems undergo a process of communicative selection and adaptation that promotes optimized sign systems. This results from the interplay between sign diversity and a global alignment constraint; pairwise interaction introduces a range of competing signs and the need to globally align on a single sign-meaning mapping for each referent applies selection pressure.

  14. The fitness and functionality of culturally evolved communication systems.

    PubMed

    Fay, Nicolas; Garrod, Simon; Roberts, Leo

    2008-11-12

    This paper assesses whether human communication systems undergo the same progressive adaptation seen in animal communication systems and concrete artefacts. Four experiments compared the fitness of ad hoc sign systems created under different conditions when participants play a graphical communication task. Experiment 1 demonstrated that when participants are organized into interacting communities, a series of signs evolve that enhance individual learning and promote efficient decoding. No such benefits are found for signs that result from the local interactions of isolated pairs of interlocutors. Experiments 2 and 3 showed that the decoding benefits associated with community evolved signs cannot be attributed to superior sign encoding or detection. Experiment 4 revealed that naive overseers were better able to identify the meaning of community evolved signs when compared with isolated pair developed signs. Hence, the decoding benefits for community evolved signs arise from their greater residual iconicity. We argue that community evolved sign systems undergo a process of communicative selection and adaptation that promotes optimized sign systems. This results from the interplay between sign diversity and a global alignment constraint; pairwise interaction introduces a range of competing signs and the need to globally align on a single sign-meaning mapping for each referent applies selection pressure. PMID:18799421

  15. Seasonal variability of soil aggregate stability

    NASA Astrophysics Data System (ADS)

    Rohoskova, M.; Kodesova, R.; Jirku, V.; Zigova, A.; Kozak, J.

    2009-04-01

    Seasonal variability of soil properties measured in surface horizons of three soil types (Haplic Luvisol, Greyic Phaeozem, Haplic Cambisol) was studied in years 2007 and 2008. Undisturbed and disturbed soil samples were taken every month to evaluate field water content, bulk density, porosity, ration of gravitational and capillary pores, pHKCl and pHH2O, organic matter content and its quality, aggregate stability using WSA index. In addition, micromorphological features of soil aggregates were studied in thin soil sections that were made from undisturbed large soil aggregates. Results showed that soil aggregate stability depended on stage of the root zone development, soil management and climatic conditions. Larger aggregate stabilities and also larger ranges of measure values were obtained in the year 2007 then those measured in 2008. This was probably caused by lower precipitations and consequently lower soil water contents observed in 2007 than those measured in 2008. The highest aggregate stability was measured at the end of April in the years 2007 and 2008 in Haplic Luvisol and Greyic Phaeozem, and at the end of June in the year 2007 and at the beginning of June in 2008 in Haplic Cambisol. In all cases aggregate stability increased during the root growth and then gradually decreased due to summer rainfall events. Aggregate stability reflected aggregate structure and soil pore system development, which was documented on micromorphological images and evaluated using the ration of gravitational and capillary pores measured on the undisturbed sol samples. Acknowledgement: Authors acknowledge the financial support of the Grant Agency of the Czech Republic grant No. 526/08/0434, and the Ministry of Education, Youth and Sports grant No. MSM 6046070901.

  16. 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

  17. Condensation versus diffusion. A spatial-scale-independent theory of aggregate structures in edible oils: applications to model systems and commercial shortenings studied via rheology and USAXS

    NASA Astrophysics Data System (ADS)

    Pink, David A.; Peyronel, Fernanda; Quinn, Bonnie; Singh, Pratham; Marangoni, Alejandro G.

    2015-09-01

    Understanding how solid fats structures come about in edible oils and quantifying their structures is of fundamental importance in developing edible oils with pre-selected characteristics. We considered the great range of fractal dimensions, from 1.91 to 2.90, reported from rheological measurements. We point out that, if the structures arise via DLA/RLA or DLCA/RLCA, as has been established using ultra small angle x-ray scattering (USAXS), we would expect fractal dimensions in the range ~1.7 to 2.1, and ~2.5 or ~3.0. We present new data for commercial fats and show that the fractal dimensions deduced lie outside these values. We have developed a model in which competition between two processes can lead to the range of fractal dimensions observed. The two processes are (i) the rate at which the solid fat particles are created as the temperature is decreased, and (ii) the rate at which these particles diffuse, thereby meeting and forming aggregates. We assumed that aggregation can take place essentially isotropically and we identified two characteristic times: a time characterizing the rate of creation of solid fats, {τ\\text{create}}(T)\\equiv 1/{{R}S}(T) , where {{R}S}(T) is the rate of solid condensation (cm3 s-1), and the diffusion time of solid fats, {τ\\text{diff}}≤ft(T,{{c}S}\\right)=< {{r}2}> /6{D}≤ft(T,{{c}S}\\right) , where {D}≤ft(T,{{c}S}\\right) is their diffusion coefficient and < {{r}2}> is the typical average distance that fats must move in order to aggregate. The intent of this model is to show that a simple process can lead to a wide range of fractal dimensions. We showed that in the limit of very fast solid creation, {τ\\text{create}}\\ll {τ\\text{diff}} the fractal dimension is predicted to be that of DLCA, ~1.7, relaxing to that of RLCA, 2.0-2.1, and that in the limit of very slow solid creation, {τ\\text{create}}\\gg {τ\\text{diff}} , the fractal dimension is predicted to be that obtained via DLA, ~2.5, relaxing to that of RLA, 3

  18. Efficient expansion of mesenchymal stromal cells in a disposable fixed bed culture system.

    PubMed

    Mizukami, Amanda; Orellana, Maristela D; Caruso, Sâmia R; de Lima Prata, Karen; Covas, Dimas T; Swiech, Kamilla

    2013-01-01

    The need for efficient and reliable technologies for clinical-scale expansion of mesenchymal stromal cells (MSC) has led to the use of disposable bioreactors and culture systems. Here, we evaluate the expansion of cord blood-derived MSC in a disposable fixed bed culture system. Starting from an initial cell density of 6.0 × 10(7) cells, after 7 days of culture, it was possible to produce of 4.2(±0.8) × 10(8) cells, which represents a fold increase of 7.0 (±1.4). After enzymatic retrieval from Fibra-Cell disks, the cells were able to maintain their potential for differentiation into adipocytes and osteocytes and were positive for many markers common to MSC (CD73, CD90, and CD105). The results obtained in this study demonstrate that MSC can be efficiently expanded in the culture system. This novel approach presents several advantages over the current expansion systems, based on culture flasks or microcarrier-based spinner flasks and represents a key element for MSC cellular therapy according to GMP compliant clinical-scale production system.

  19. Cometabolism of Monochloramine by Distribution System Relevant Mixed Culture Nitrifiers

    EPA Science Inventory

    Monochloramine (NH2Cl) is increasingly used as a residual disinfectant. A major problem related to NH2Cl is nitrification in distribution systems, leading to rapid NH2Cl residual loss. Ammonia-oxidizing bacteria (AOB), which oxidize ammonia (NH3) to nitrite, can cometabolize chem...

  20. Chondrogenesis in aggregates of embryonic limb cells grown in a rotating wall vessel

    NASA Astrophysics Data System (ADS)

    Duke, J.; Daane, E.; Arizpe, J.; Montufar-Solis, D.

    Previous studies in this lab have shown that chondrogenesis is affected in growth plates of rats exposed to microgravity, and in micromass cultures of embryonic limb mesenchyme differentiating in space. In order to provide a three dimensional aspect not seen in the micromass system, and a tissue homogeneity not possible with explants of limb or limb elements, and to alleviate certain difficulties regarding crew time and stowage, we began culturing embryonic limb cells in Rotating Wall Vessels (RWV). First, these cells were attached to beads, and grown for up to 65 days in a type of RWV known as STLV at the Johnson Space Center. During this time, the cells and beads aggregated and the aggregates continued to increase in size, and differentiated into Alcian blue staining chondrocytes. Because our intent was to use these aggregates for implanting into bony defects in addition to their use in studies of chondrogenic regulation at 1g and mug, aggregates of these cells without beads were grown in the commercially available version of the STLV, and their ability to ossify when subcutaneously implanted assessed.

  1. The Transformation of Ergonomic Affordances into Cultural Affordances: The Case of the Alnuset System

    ERIC Educational Resources Information Center

    Chiappini, Giampaolo

    2012-01-01

    Is it possible to study the ergonomic affordances offered by a system designed for educational aims and their transformation into cultural affordances? To this purpose, what references can we adopt? This work describes the theoretical framework used to realise this study referring to AlNuSet, a system realised within the EC ReMath project to…

  2. Organizational Culture and the Design of Computer-Mediated Communication Systems: Issues for Organizational Communication Research.

    ERIC Educational Resources Information Center

    Hacker, Kenneth L.; And Others

    The study of computer mediated communication (CMC) systems in organizations is necessary for a complete examination and explanation of organizational culture and communication. Research has shown that the effects of CMC systems have been both positive and negative. Positively, they have helped to augment oral communication. Negatively, they have…

  3. Revisiting Bourdieu: Alternative Educational Systems in the Light of the Theory of Social and Cultural Reproduction

    ERIC Educational Resources Information Center

    Azaola, Marta Cristina

    2012-01-01

    The paper reflects upon the principles and practice of an alternative educational system operating in rural Mexico in the light of Bourdieu's theory of cultural and social reproduction. Bourdieu's theory seeks to explain processes of reproduction of power relations within schools and society; whereas alternative educational systems seek to expand…

  4. Culture, Indigenous Knowledge Systems and Sustainable Development: A Critical View of Education in an African Context

    ERIC Educational Resources Information Center

    Breidlid, Anders

    2009-01-01

    The article's focus is the relationship between culture, indigenous knowledge systems (IKS), sustainable development and education in Africa. It analyzes the concept of sustainability with particular reference to education and indigenous knowledge systems. In particular the article analyzes the documents from the World Summit in Johannesburg in…

  5. 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.

  6. Aggregation of Sea Urchin Phagocytes Is Augmented In Vitro by Lipopolysaccharide

    PubMed Central

    Majeske, Audrey J.; Bayne, Christopher J.; Smith, L. Courtney

    2013-01-01

    Development of protocols and media for culturing immune cells from marine invertebrates has not kept pace with advancements in mammalian immune cell culture, the latter having been driven by the need to understand the causes of and develop therapies for human and animal diseases. However, expansion of the aquaculture industry and the diseases that threaten these systems creates the need to develop cell and tissue culture methods for marine invertebrates. Such methods will enable us to better understand the causes of disease outbreaks and to develop means to avoid and remedy epidemics. We report a method for the short-term culture of phagocytes from the purple sea urchin, Strongylocentrotus purpuratus, by modifying an approach previously used to culture cells from another sea urchin species. The viability of cultured phagocytes from the purple sea urchin decreases from 91.6% to 57% over six days and phagocyte morphology changes from single cells to aggregates leading to the formation of syncytia-like structures. This process is accelerated in the presence of lipopolysaccharide suggesting that phagocytes are capable of detecting this molecular pattern in culture conditions. Sea urchin immune response proteins, called Sp185/333, are expressed on the surface of a subset of phagocytes and have been associated with syncytia-like structures. We evaluated their expression in cultured phagocytes to determine their possible role in cell aggregation and in the formation of syncytia-like structures. Between 0 and 3 hr, syncytia-like structures were observed in cultures when only ∼10% of the cells were positive for Sp185/333 proteins. At 24 hr, ∼90% of the nuclei were Sp185/333-positive when all of the phagocytes had aggregated into syncytia-like structures. Consequently, we conclude that the Sp185/333 proteins do not have a major role in initiating the aggregation of cultured phagocytes, however the Sp185/333 proteins are associated with the clustered nuclei within the

  7. The cultural articulation of patriarchy: legal systems, Islam and women.

    PubMed

    Shaheed, F

    1986-01-01

    Patriarchy in Pakistan results in inequalities to women. Issues emphasized include Islamic customary laws, the movement to Islamize penal and social behavioral codes, the mislabeling of Islamic beliefs as "westernization", and the rising women's movement's attempt to oppose present trends. Many practices thought to reflect Muslim culture are really the infliction of Islamic religious principles on pre-existing behavioral codes in Pakistan; thus, such practices are not actually Islamic teachings and are used to control social behavior. It is necessary to separate Islamic institution and actual Pakistanian practices in order to identify Islamic ideology's role in sustaining and vindicating patriachary. 3 roots of shaping jurisprudence are customary law, religious law, and British civil and criminal law. Further investigation of customary and religious laws currently employed indicates acceptance of Muslim practices promoting superiority of men and rejection of Islamic teachings promoting women's rights. Such Islamic teachings include a marriage settlement requiring men to give money to their wives, acknowledgement of marriages as an agreement between consenting adults, and a woman's right to divorce. Customs contradicting Islamic teachings and leading to inequalities for women include denial of a woman's access to economic resources, the annulment of the marriage settlement, and the relative ease of Muslim men to divorce their wives. Some communities practice purdah in which women are secluded from men and excluded in economic and political decisions. Such social restrictions minimize women's involvement in political decision making and in the judiciary. Exercising their right to vote and participating in trade unions, women would influence decision making. Resistance to current practices has been trade unions, women could influence decision making. resistance to current practices has been primarily from upper and middle class women; but to be effective all classes

  8. The cultural articulation of patriarchy: legal systems, Islam and women.

    PubMed

    Shaheed, F

    1986-01-01

    Patriarchy in Pakistan results in inequalities to women. Issues emphasized include Islamic customary laws, the movement to Islamize penal and social behavioral codes, the mislabeling of Islamic beliefs as "westernization", and the rising women's movement's attempt to oppose present trends. Many practices thought to reflect Muslim culture are really the infliction of Islamic religious principles on pre-existing behavioral codes in Pakistan; thus, such practices are not actually Islamic teachings and are used to control social behavior. It is necessary to separate Islamic institution and actual Pakistanian practices in order to identify Islamic ideology's role in sustaining and vindicating patriachary. 3 roots of shaping jurisprudence are customary law, religious law, and British civil and criminal law. Further investigation of customary and religious laws currently employed indicates acceptance of Muslim practices promoting superiority of men and rejection of Islamic teachings promoting women's rights. Such Islamic teachings include a marriage settlement requiring men to give money to their wives, acknowledgement of marriages as an agreement between consenting adults, and a woman's right to divorce. Customs contradicting Islamic teachings and leading to inequalities for women include denial of a woman's access to economic resources, the annulment of the marriage settlement, and the relative ease of Muslim men to divorce their wives. Some communities practice purdah in which women are secluded from men and excluded in economic and political decisions. Such social restrictions minimize women's involvement in political decision making and in the judiciary. Exercising their right to vote and participating in trade unions, women would influence decision making. Resistance to current practices has been trade unions, women could influence decision making. resistance to current practices has been primarily from upper and middle class women; but to be effective all classes

  9. Development of a definition, classification system, and model for cultural geology

    NASA Astrophysics Data System (ADS)

    Mitchell, Lloyd W., III

    The concept for this study is based upon a personal interest by the author, an American Indian, in promoting cultural perspectives in undergraduate college teaching and learning environments. Most academicians recognize that merged fields can enhance undergraduate curricula. However, conflict may occur when instructors attempt to merge social science fields such as history or philosophy with geoscience fields such as mining and geomorphology. For example, ideologies of Earth structures derived from scientific methodologies may conflict with historical and spiritual understandings of Earth structures held by American Indians. Specifically, this study addresses the problem of how to combine cultural studies with the geosciences into a new merged academic discipline called cultural geology. This study further attempts to develop the merged field of cultural geology using an approach consisting of three research foci: a definition, a classification system, and a model. Literature reviews were conducted for all three foci. Additionally, to better understand merged fields, a literature review was conducted specifically for academic fields that merged social and physical sciences. Methodologies concentrated on the three research foci: definition, classification system, and model. The definition was derived via a two-step process. The first step, developing keyword hierarchical ranking structures, was followed by creating and analyzing semantic word meaning lists. The classification system was developed by reviewing 102 classification systems and incorporating selected components into a system framework. The cultural geology model was created also utilizing a two-step process. A literature review of scientific models was conducted. Then, the definition and classification system were incorporated into a model felt to reflect the realm of cultural geology. A course syllabus was then developed that incorporated the resulting definition, classification system, and model. This

  10. Implementation of culturally targeted patient navigation system for screening colonoscopy in a direct referral system.

    PubMed

    Jandorf, Lina; Cooperman, Julia L; Stossel, Lauren M; Itzkowitz, Steven; Thompson, Hayley S; Villagra, Cristina; Thélémaque, Linda D; McGinn, Thomas; Winkel, Gary; Valdimarsdottir, Heiddis; Shelton, Rachel C; Redd, William

    2013-10-01

    Low-income minorities often face system-based and personal barriers to screening colonoscopy (SC). Culturally targeted patient navigation (CTPN) programs employing professional navigators (Pro-PNs) or community-based peer navigators (Peer-PNs) can help overcome barriers but are not widely implemented. In East Harlem, NY, USA, where approximately half the residents participate in SC, 315 African American patients referred for SC at a primary care clinic with a Direct Endoscopic Referral System were recruited between May 2008 and May 2010. After medical clearance, 240 were randomized to receive CTPN delivered by a Pro-PN (n = 106) or Peer-PN (n = 134). Successful navigation was measured by SC adherence rate, patient satisfaction and navigator trust. Study enrollment was 91.4% with no significant differences in SC adherence rates between Pro-PN (80.0%) and Peer-PN (71.3%) (P = 0.178). Participants in both groups reported high levels of satisfaction and trust. These findings suggest that CTPN Pro-PN and Peer-PN programs are effective in this urban primary care setting. We detail how we recruited and trained navigators, how CTPN was implemented and provide a preliminary answer to our questions of the study aims: can peer navigators be as effective as professionals and what is the potential impact of patient navigation on screening adherence?

  11. The rat whole embryo culture assay using the Dysmorphology Score system.

    PubMed

    Zhang, Cindy; Panzica-Kelly, Julie; Augustine-Rauch, Karen

    2013-01-01

    The rat whole embryo culture (WEC) system has been used extensively for characterizing teratogenic properties of test chemicals. In this chapter, we describe the methodology for culturing rat embryos as well as a new morphological score system, the Dysmorphology Score (DMS) system for assessing morphology of mid gestation (gestational day 11) rat embryos. In contrast to the developmental stage focused scoring associated with the Brown and Fabro score system, this new score system assesses the respective degree of severity of dysmorphology, which delineates normal from abnormal morphology of specific embryonic structures and organ systems. This score system generates an approach that allows rapid identification and quantification of adverse developmental findings, making it conducive for characterization of compounds for teratogenic properties and screening activities.

  12. Submicromolar Aβ42 reduces hippocampal glutamate receptors and presynaptic markers in an aggregation-dependent manner

    PubMed Central

    Wisniewski, Meagan L.; Hwang, Jeannie; Bahr, Ben A.

    2011-01-01

    Synaptic pathology in Alzheimer's disease brains is thought to involve soluble Aβ42 peptide. Here, sterile incubation in PBS caused small Aβ42 oligomer formation as well as heterogeneous, 6E10-immunopositive aggregates of 80-100 kDa. High molecular weight aggregates (H-agg) formed in a time-dependent manner over an extended 30-day period. Interestingly, an inverse relationship between dimeric and H-agg formation was more evident when incubations were performed at 37°C as compared to 23°C, thus providing an experimental strategy with which to address synaptic compromise produced by the different Aβ aggregates. H-agg species formed faster and to higher levels at 37°C compared to 23°C, and the two aggregate preparations were evaluated in hippocampal slice cultures, a sensitive system for monitoring synaptic integrity. Applied daily at 80-600 nM for 7 days, the Aβ42 preparations caused dose-dependent and aggregation-dependent declines in α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) and N-methyl-D-aspartate (NMDA) receptor subunits as well as in presynaptic components. Unlike the synaptic effects, Aβ42 induced only trace cellular degeneration that was CA1 specific. The 37°C preparation was less effective at decreasing synaptic markers, corresponding with its reduced levels of Aβ42 monomers and dimers. Aβ42 dimers decayed significantly faster at 37°C than 23°C, and more rapidly than monomers at either temperature. These findings indicate that Aβ42 can self-aggregate into potent synaptotoxic oligomers as well as into larger aggregates that may serve to neutralize the toxic formations. These results will add to the growing debate concerning whether high molecular weight Aβ complexes that form amyloid plaques are protective through the sequestration of oligomeric species. PMID:21978994

  13. A Novel Method to Quantify Soil Aggregate Stability by Measuring Aggregate Bond Energies

    NASA Astrophysics Data System (ADS)

    Efrat, Rachel; Rawlins, Barry G.; Quinton, John N.; Watts, Chris W.; Whitmore, Andy P.

    2016-04-01

    Soil aggregate stability is a key indicator of soil quality because it controls physical, biological and chemical functions important in cultivated soils. Micro-aggregates are responsible for the long term sequestration of carbon in soil, therefore determine soils role in the carbon cycle. It is thus vital that techniques to measure aggregate stability are accurate, consistent and reliable, in order to appropriately manage and monitor soil quality, and to develop our understanding and estimates of soil as a carbon store to appropriately incorporate in carbon cycle models. Practices used to assess the stability of aggregates vary in sample preparation, operational technique and unit of results. They use proxies and lack quantification. Conflicting results are therefore drawn between projects that do not provide methodological or resultant comparability. Typical modern stability tests suspend aggregates in water and monitor fragmentation upon exposure to an un-quantified amount of ultrasonic energy, utilising a laser granulometer to measure the change in mean weight diameter. In this project a novel approach has been developed based on that of Zhu et al., (2009), to accurately quantify the stability of aggregates by specifically measuring their bond energies. The bond energies are measured operating a combination of calorimetry and a high powered ultrasonic probe, with computable output function. Temperature change during sonication is monitored by an array of probes which enables calculation of the energy spent heating the system (Ph). Our novel technique suspends aggregates in heavy liquid lithium heteropolytungstate, as opposed to water, to avoid exposing aggregates to an immeasurable disruptive energy source, due to cavitation, collisions and clay swelling. Mean weight diameter is measured by a laser granulometer to monitor aggregate breakdown after successive periods of calculated ultrasonic energy input (Pi), until complete dispersion is achieved and bond

  14. Cross-cultural effect on the brain revisited: universal structures plus writing system variation.

    PubMed

    Bolger, Donald J; Perfetti, Charles A; Schneider, Walter

    2005-05-01

    Recognizing printed words requires the mapping of graphic forms, which vary with writing systems, to linguistic forms, which vary with languages. Using a newly developed meta-analytic approach, aggregated Gaussian-estimated sources (AGES; Chein et al. [2002]: Psychol Behav 77:635-639), we examined the neuroimaging results for word reading within and across writing systems and languages. To find commonalities, we compiled 25 studies in English and other Western European languages that use an alphabetic writing system, 9 studies of native Chinese reading, 5 studies of Japanese Kana (syllabic) reading, and 4 studies of Kanji (morpho-syllabic) reading. Using the AGES approach, we created meta-images within each writing system, isolated reliable foci of activation, and compared findings across writing systems and languages. The results suggest that these writing systems utilize a common network of regions in word processing. Writing systems engage largely the same systems in terms of gross cortical regions, but localization within those regions suggests differences across writing systems. In particular, the region known as the visual word form area (VWFA) shows strikingly consistent localization across tasks and across writing systems. This region in the left mid-fusiform gyrus is critical to word recognition across writing systems and languages.

  15. An alternative long-term culture system for highly-pure mouse spermatogonial stem cells.

    PubMed

    He, Bao-Rong; Lu, Fan; Zhang, Lingling; Hao, Ding-Jun; Yang, Hao

    2015-06-01

    Increasing evidence suggests that spermatogonial stem cells (SSCs) have great clinical potential to give rise to a variety of cell types besides all spermatogenic lineage cells. The development of an efficient method for long-term culture of highly-pure SSCs is essential for further studies related to SSC biological events. Here, we describe an in vitro culture system obtaining mouse SSC cultures of high purity, viability, and proliferation. For establishing long-term cultures of SSCs, we mainly focused on isolation procedures and culture conditions. These included co-coating of extracellular substrates, that is, poly-L-lysine (PLL) and laminin, as well as combinatiorial use of three milder enzymes and simultaneously less trypsin to minimize enzyme-mediated degradation of SSCs. Furthermore, a unique purification procedure was performed to effectively eliminate contaminating non-SSCs. Finally, a critical step is to ensure SSC maintenance and expansion by utilizing optimal culture medium. Obtained data suggest that applying our optimally modified method, SSCs can be cultured for over 90 days with high purity (around 93.5%). Moreover, SSCs isolated and expanded using our protocol fulfills all criteria of SSCs without losing their stemness-characterized by SSC-phenotypic gene expression and long-term self-renewal. This study describes for the first time a protocol allowing isolation and expansion of SSCs suitable for numerous studies related to SSC-based clinical therapies of various diseases.

  16. Large-scale clinical comparison of the lysis-centrifugation and radiometric systems for blood culture

    SciTech Connect

    Brannon, P.; Kiehn, T.E.

    1985-12-01

    The Isolator 10 lysis-centrifugation blood culture system (E. I. du Pont de Nemours and Co., Inc., Wilmington, Del.) was compared with the BACTEC radiometric method (Johnston Laboratories, Inc., Towson, Md.) with 6B and 7D broth media for the recovery of bacteria and yeasts. From 11,000 blood cultures, 1,174 clinically significant organisms were isolated. The Isolator system recovered significantly more total organisms, members of the family Enterobacteriaceae, Staphylococcus spp., and yeasts. The BACTEC system recovered significantly more Pseudomonas spp., Streptococcus spp., and anaerobes. Of the Isolator colony counts, 87% measured less than 11 CFU/ml of blood. Organisms, on an average, were detected the same day from each of the two culture systems. Only 13 of the 975 BACTEC isolates (0.01%) were recovered by subculture of growth-index-negative bottles, and 12 of the 13 were detected in another broth blood culture taken within 24 h. Contaminants were recovered from 4.8% of the Isolator 10 and 2.3% of the BACTEC cultures.

  17. Garlic exerts allelopathic effects on pepper physiology in a hydroponic co-culture system

    PubMed Central

    Ding, Haiyan; Liu, Menglong; Hayat, Sikandar; Feng, Han

    2016-01-01

    ABSTRACT A hydroponic co-culture system was adopted to determine the allelopathic potential of garlic on the growth of pepper plants. Different numbers of garlic plants (0, 2, 4, 8 and 12) were hydroponically co-cultured with two pepper plants to investigate allelopathic effects on the growth attributes and antioxidative defense system of the test pepper plants. The responses of the pepper plants depended on the number of garlic plants included in the co-culture system, indicating an association of pepper growth with the garlic root exudate concentration. When grown at a pepper/garlic ratio of 1:1 or 1:2, the pepper plant height, chlorophyll content, and peroxidase (POD), catalase (CAT) and phenylalanine ammonia-lyase (PAL) activities were significantly increased after 30 days of co-culture; in contrast, reduction in methane dicarboxylic aldehyde (MDA) content was observed. However, when the pepper/garlic ratio was 1:4 or higher, these morphological indices and protective enzyme activities were significantly inhibited, whereas MDA levels in the pepper leaves were significantly increased due to severe membrane lipid peroxidation. The results indicate that although low concentrations of garlic root exudates appear to induce protective enzyme systems and promote pepper growth, high concentrations have deleterious effects. These findings suggest that further investigations should optimize the co-culture pepper/garlic ratio to reduce continuous cropping obstacles in pepper production. PMID:27095440

  18. Garlic exerts allelopathic effects on pepper physiology in a hydroponic co-culture system.

    PubMed

    Ding, Haiyan; Cheng, Zhihui; Liu, Menglong; Hayat, Sikandar; Feng, Han

    2016-01-01

    A hydroponic co-culture system was adopted to determine the allelopathic potential of garlic on the growth of pepper plants. Different numbers of garlic plants (0, 2, 4, 8 and 12) were hydroponically co-cultured with two pepper plants to investigate allelopathic effects on the growth attributes and antioxidative defense system of the test pepper plants. The responses of the pepper plants depended on the number of garlic plants included in the co-culture system, indicating an association of pepper growth with the garlic root exudate concentration. When grown at a pepper/garlic ratio of 1:1 or 1:2, the pepper plant height, chlorophyll content, and peroxidase (POD), catalase (CAT) and phenylalanine ammonia-lyase (PAL) activities were significantly increased after 30 days of co-culture; in contrast, reduction in methane dicarboxylic aldehyde (MDA) content was observed. However, when the pepper/garlic ratio was 1:4 or higher, these morphological indices and protective enzyme activities were significantly inhibited, whereas MDA levels in the pepper leaves were significantly increased due to severe membrane lipid peroxidation. The results indicate that although low concentrations of garlic root exudates appear to induce protective enzyme systems and promote pepper growth, high concentrations have deleterious effects. These findings suggest that further investigations should optimize the co-culture pepper/garlic ratio to reduce continuous cropping obstacles in pepper production. PMID:27095440

  19. Garlic exerts allelopathic effects on pepper physiology in a hydroponic co-culture system.

    PubMed

    Ding, Haiyan; Cheng, Zhihui; Liu, Menglong; Hayat, Sikandar; Feng, Han

    2016-05-15

    A hydroponic co-culture system was adopted to determine the allelopathic potential of garlic on the growth of pepper plants. Different numbers of garlic plants (0, 2, 4, 8 and 12) were hydroponically co-cultured with two pepper plants to investigate allelopathic effects on the growth attributes and antioxidative defense system of the test pepper plants. The responses of the pepper plants depended on the number of garlic plants included in the co-culture system, indicating an association of pepper growth with the garlic root exudate concentration. When grown at a pepper/garlic ratio of 1:1 or 1:2, the pepper plant height, chlorophyll content, and peroxidase (POD), catalase (CAT) and phenylalanine ammonia-lyase (PAL) activities were significantly increased after 30 days of co-culture; in contrast, reduction in methane dicarboxylic aldehyde (MDA) content was observed. However, when the pepper/garlic ratio was 1:4 or higher, these morphological indices and protective enzyme activities were significantly inhibited, whereas MDA levels in the pepper leaves were significantly increased due to severe membrane lipid peroxidation. The results indicate that although low concentrations of garlic root exudates appear to induce protective enzyme systems and promote pepper growth, high concentrations have deleterious effects. These findings suggest that further investigations should optimize the co-culture pepper/garlic ratio to reduce continuous cropping obstacles in pepper production.

  20. Interferon Response in Hepatitis C Virus (HCV) Infection: Lessons from Cell Culture Systems of HCV Infection.

    PubMed

    Sung, Pil Soo; Shin, Eui-Cheol; Yoon, Seung Kew

    2015-01-01

    Hepatitis C virus (HCV) is a positive-stranded RNA virus that infects approximately 130-170 million people worldwide. In 2005, the first HCV infection system in cell culture was established using clone JFH-1, which was isolated from a Japanese patient with fulminant HCV infection. JFH-1 replicates efficiently in hepatoma cells and infectious virion particles are released into the culture supernatant. The development of cell culture-derived HCV (HCVcc) systems has allowed us to understand how hosts respond to HCV infection and how HCV evades host responses. Although the mechanisms underlying the different outcomes of HCV infection are not fully understood, innate immune responses seem to have a critical impact on the outcome of HCV infection, as demonstrated by the prognostic value of IFN-λ gene polymorphisms among patients with chronic HCV infection. Herein, we review recent research on interferon response in HCV infection, particularly studies using HCVcc infection systems.

  1. An integrated system for synchronous culture of animal cells under controlled conditions.

    PubMed

    Mendoza-Pérez, Elena; Hernández, Vanessa; Palomares, Laura A; Serrato, José A

    2016-01-01

    The cell cycle has fundamental effects on cell cultures and their products. Tools to synchronize cultured cells allow the study of cellular physiology and metabolism at particular cell cycle phases. However, cells are most often arrested by methods that alter their homeostasis and are then cultivated in poorly controlled environments. Cell behavior could then be affected by the synchronization method and culture conditions used, and not just by the particular cell cycle phase under study. Moreover, only a few viable cells are recovered. Here, we designed an integrated system where a large number of cells from a controlled bioreactor culture is separated by centrifugal elutriation at high viabilities. In contrast to current elutriation methods, cells are injected directly from a bioreactor into an injection loop, allowing the introduction of a large number of cells into the separation chamber without stressful centrifugation. A low pulsation peristaltic pump increases the stability of the elutriation chamber. Using this approach, a large number of healthy cells at each cell cycle phase were obtained, allowing their direct inoculation into fully instrumented bioreactors. Hybridoma cells synchronized and cultured in this system behaved as expected for a synchronous culture. PMID:27625207

  2. An integrated system for synchronous culture of animal cells under controlled conditions.

    PubMed

    Mendoza-Pérez, Elena; Hernández, Vanessa; Palomares, Laura A; Serrato, José A

    2016-01-01

    The cell cycle has fundamental effects on cell cultures and their products. Tools to synchronize cultured cells allow the study of cellular physiology and metabolism at particular cell cycle phases. However, cells are most often arrested by methods that alter their homeostasis and are then cultivated in poorly controlled environments. Cell behavior could then be affected by the synchronization method and culture conditions used, and not just by the particular cell cycle phase under study. Moreover, only a few viable cells are recovered. Here, we designed an integrated system where a large number of cells from a controlled bioreactor culture is separated by centrifugal elutriation at high viabilities. In contrast to current elutriation methods, cells are injected directly from a bioreactor into an injection loop, allowing the introduction of a large number of cells into the separation chamber without stressful centrifugation. A low pulsation peristaltic pump increases the stability of the elutriation chamber. Using this approach, a large number of healthy cells at each cell cycle phase were obtained, allowing their direct inoculation into fully instrumented bioreactors. Hybridoma cells synchronized and cultured in this system behaved as expected for a synchronous culture.

  3. 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.

  4. Three cyanobacteriochromes work together to form a light color-sensitive input system for c-di-GMP signaling of cell aggregation

    PubMed Central

    Enomoto, Gen; Ni-Ni-Win; Narikawa, Rei; Ikeuchi, Masahiko

    2015-01-01

    Cyanobacteriochromes (CBCRs) are cyanobacterial photoreceptors that have diverse spectral properties and domain compositions. Although large numbers of CBCR genes exist in cyanobacterial genomes, no studies have assessed whether multiple CBCRs work together. We recently showed that the diguanylate cyclase (DGC) activity of the CBCR SesA from Thermosynechococcus elongatus is activated by blue-light irradiation and that, when irradiated, SesA, via its product cyclic dimeric GMP (c-di-GMP), induces aggregation of Thermosynechococcus vulcanus cells at a temperature that is suboptimum for single-cell viability. For this report, we first characterize the photobiochemical properties of two additional CBCRs, SesB and SesC. Blue/teal light-responsive SesB has only c-di-GMP phosphodiesterase (PDE) activity, which is up-regulated by teal light and GTP. Blue/green light-responsive SesC has DGC and PDE activities. Its DGC activity is enhanced by blue light, whereas its PDE activity is enhanced by green light. A ΔsesB mutant cannot suppress cell aggregation under teal-green light. A ΔsesC mutant shows a less sensitive cell-aggregation response to ambient light. ΔsesA/ΔsesB/ΔsesC shows partial cell aggregation, which is accompanied by the loss of color dependency, implying that a nonphotoresponsive DGC(s) producing c-di-GMP can also induce the aggregation. The results suggest that SesB enhances the light color dependency of cell aggregation by degrading c-di-GMP, is particularly effective under teal light, and, therefore, seems to counteract the induction of cell aggregation by SesA. In addition, SesC seems to improve signaling specificity as an auxiliary backup to SesA/SesB activities. The coordinated action of these three CBCRs highlights why so many different CBCRs exist. PMID:26080423

  5. Three cyanobacteriochromes work together to form a light color-sensitive input system for c-di-GMP signaling of cell aggregation.

    PubMed

    Enomoto, Gen; Ni-Ni-Win; Narikawa, Rei; Ikeuchi, Masahiko

    2015-06-30

    Cyanobacteriochromes (CBCRs) are cyanobacterial photoreceptors that have diverse spectral properties and domain compositions. Although large numbers of CBCR genes exist in cyanobacterial genomes, no studies have assessed whether multiple CBCRs work together. We recently showed that the diguanylate cyclase (DGC) activity of the CBCR SesA from Thermosynechococcus elongatus is activated by blue-light irradiation and that, when irradiated, SesA, via its product cyclic dimeric GMP (c-di-GMP), induces aggregation of Thermosynechococcus vulcanus cells at a temperature that is suboptimum for single-cell viability. For this report, we first characterize the photobiochemical properties of two additional CBCRs, SesB and SesC. Blue/teal light-responsive SesB has only c-di-GMP phosphodiesterase (PDE) activity, which is up-regulated by teal light and GTP. Blue/green light-responsive SesC has DGC and PDE activities. Its DGC activity is enhanced by blue light, whereas its PDE activity is enhanced by green light. A ΔsesB mutant cannot suppress cell aggregation under teal-green light. A ΔsesC mutant shows a less sensitive cell-aggregation response to ambient light. ΔsesA/ΔsesB/ΔsesC shows partial cell aggregation, which is accompanied by the loss of color dependency, implying that a nonphotoresponsive DGC(s) producing c-di-GMP can also induce the aggregation. The results suggest that SesB enhances the light color dependency of cell aggregation by degrading c-di-GMP, is particularly effective under teal light, and, therefore, seems to counteract the induction of cell aggregation by SesA. In addition, SesC seems to improve signaling specificity as an auxiliary backup to SesA/SesB activities. The coordinated action of these three CBCRs highlights why so many different CBCRs exist.

  6. Consideration of the cellular microenvironment: physiologically relevant co-culture systems in drug discovery.

    PubMed

    L Berg, Ellen; Hsu, Yu-Chih; Lee, Jonathan A

    2014-04-01

    There is renewed interest in phenotypic approaches to drug discovery, using cell-based assays to select new drugs, with the goal of improving pharmaceutical success. Assays that are more predictive of human biology can help researchers achieve this goal. Primary cells are more physiologically relevant to human biology and advances are being made in methods to expand the available cell types and improve the potential clinical translation of these assays through the use of co-cultures or three-dimensional (3D) technologies. Of particular interest are assays that may be suitable for industrial scale drug discovery. Here we review the use of primary human cells and co-cultures in drug discovery and describe the characteristics of co-culture models for inflammation biology (BioMAP systems), neo-vascularization and tumor microenvironments. Finally we briefly describe technical trends that may enable and impact the development of physiologically relevant co-culture assays in the near future. PMID:24524933

  7. The response of mineralizing culture systems to microtextured and polished titanium surfaces.

    PubMed

    Hacking, S Adam; Harvey, Edward; Roughley, Peter; Tanzer, Michael; Bobyn, John

    2008-10-01

    The surface texture of titanium has a predictable effect on peri-implant tissue formation in vivo. When implanted in an osseous environment, smooth surfaces (R(a) < 0.5 mm) are generally apposed by fibrous tissue and textured surfaces (R(a) > 1.0 mm) are generally apposed by osseous tissue. Thus in vitro study assessed the mineralization and proliferation response of TF274, MC3T3-E1, murine femoral stromal cells and canine stromal cells to tissue culture plastic (R(a) = 0.001 mm), polished (R(a) = 0.01 mm) and irregularly textured (R(a) = 3.26 mm) titanium surfaces. Amongst all culture systems, proliferation was significantly decreased on textured vs. smooth surfaces. Midway through the culture of the canine marrow cells, the cell layer detached from the tissue culture plastic and polished titanium surfaces. The TF274, MC3T3-E1, murine femoral stromal cell systems formed a mineralized matrix on the tissue culture plastic and polished titanium surfaces which was not observed with the canine stromal cell system. Compared to the tissue culture plastic and polished titanium surfaces, matrix mineralization was significantly reduced on the textured titanium surfaces for the TF274, MC3T3-E1, murine femoral stromal systems, a result which was differed significantly in comparison to the canine stromal system. These results were surprising given the large number of reports concerning the in vivo response to titanium in clinical and pre-clinical studies. Further work is required to determine if the TF274, MC3T3-E1 and murine femoral stromal systems are suitable for the in vitro investigation of the effects of titanium surface texture on osteoblast activity.

  8. Proteomics analysis of nasopharyngeal carcinoma cell secretome using a hollow fiber culture system and mass spectrometry.

    PubMed

    Wu, Hsin-Yi; Chang, Ying-Hwa; Chang, Yu-Chen; Liao, Pao-Chi

    2009-01-01

    Secreted proteins, referred to as the secretome, are known to regulate a variety of biological functions and are involved in a multitude of pathological processes. However, some secreted proteins from cell cultures are difficult to detect because of their intrinsic low abundance. They are frequently masked by proteins shed from lysed cells and the substantial amounts of serum proteins used in culture medium. We have proposed an analytical platform for sensitive detection of secreted proteins by utilizing a hollow fiber culture (HFC) system coupled with proteomic approaches. The HFC system enables culture of high-density cells in a small volume where secreted proteins can be accumulated. In addition, cell lysis rates can be greatly reduced, which alleviates the contamination from lysed cells. In this study, nasopharyngeal carcinoma (NPC) cells were utilized to evaluate the efficiency of this system in the collection and analysis of the cell secretome. Cells were adapted to serum-free medium and inoculated into the HFC system. The cell lysis rate in the culture system was estimated to be 0.001-0.022%, as determined by probing four intracellular proteins in the conditioned medium (CM), while a cell lysis rate of 0.32-1.84% was observed in dish cultures. Proteins in the CM were analyzed using SDS-PAGE and liquid chromatography tandem mass spectrometry (LC-MS/MS). A total of 134 proteins were identified in 62 gel bands, of which 61% possess a signal peptide and/or a transmembrane domain. In addition, 37% of the identified secretome were classified as extracellular or membrane proteins, whereas 98% of the lysate proteins were identified as intracellular proteins. We suggest that the HFC system may be used to collect secreted proteins efficiently and facilitate comprehensive characterization of cell secretome. PMID:19012429

  9. Spheroid formation of human thyroid cancer cells in an automated culturing system during the Shenzhou-8 Space mission.

    PubMed

    Pietsch, Jessica; Ma, Xiao; Wehland, Markus; Aleshcheva, Ganna; Schwarzwälder, Achim; Segerer, Jürgen; Birlem, Maria; Horn, Astrid; Bauer, Johann; Infanger, Manfred; Grimm, Daniela

    2013-10-01

    Human follicular thyroid cancer cells were cultured in Space to investigate the impact of microgravity on 3D growth. For this purpose, we designed and constructed a cell container that can endure enhanced physical forces, is connected to fluid storage chambers, performs media changes and cell harvesting automatically and supports cell viability. The container consists of a cell suspension chamber, two reserve tanks for medium and fixative and a pump for fluid exchange. The selected materials proved durable, non-cytotoxic, and did not inactivate RNAlater. This container was operated automatically during the unmanned Shenzhou-8 Space mission. FTC-133 human follicular thyroid cancer cells were cultured in Space for 10 days. Culture medium was exchanged after 5 days in Space and the cells were fixed after 10 days. The experiment revealed a scaffold-free formation of extraordinary large three-dimensional aggregates by thyroid cancer cells with altered expression of EGF and CTGF genes under real microgravity.

  10. Influence of polysaccharides on wine protein aggregation.

    PubMed

    Jaeckels, Nadine; Meier, Miriam; Dietrich, Helmut; Will, Frank; Decker, Heinz; Fronk, Petra

    2016-06-01

    Polysaccharides are the major high-molecular weight components of wines. In contrast, proteins occur only in small amounts in wine, but contribute to haze formation. The detailed mechanism of aggregation of these proteins, especially in combination with other wine components, remains unclear. This study demonstrates the different aggregation behavior between a buffer and a model wine system by dynamic light scattering. Arabinogalactan-protein, for example, shows an increased aggregation in the model wine system, while in the buffer system a reducing effect is observed. Thus, we could show the importance to examine the behavior of wine additives under conditions close to reality, instead of simpler buffer systems. Additional experiments on melting points of wine proteins reveal that only some isoforms of thaumatin-like proteins and chitinases are involved in haze formation. We can confirm interactions between polysaccharides and proteins, but none of these polysaccharides is able to prevent haze in wine.

  11. The Impact of National Cultural Differences on Nurses' Acceptance of Hospital Information Systems.

    PubMed

    Lin, Hsien-Cheng

    2015-06-01

    This study aims to explore the influence of national cultural differences on nurses' perceptions of their acceptance of hospital information systems. This study uses the perspective of Technology Acceptance Model; national cultural differences in terms of masculinity/femininity, individualism/collectivism, power distance, and uncertainty avoidance are incorporated into the Technology Acceptance Model as moderators, whereas time orientation is a control variable on hospital information system acceptance. A quantitative research design was used in this study; 261 participants, US and Taiwan RNs, all had hospital information system experience. Data were collected from November 2013 to February 2014 and analyzed using a t test to compare the coefficients for each moderator. The results show that individualism/collectivism, power distance, and uncertainty avoidance all exhibit significant difference on hospital information system acceptance; however, both masculinity/femininity and time orientation factors did not show significance. This study verifies that national cultural differences have significant influence on nurses' behavioral intention to use hospital information systems. Therefore, hospital information system providers should emphasize the way in which to integrate different technological functions to meet the needs of nurses from various cultural backgrounds. PMID:25899441

  12. The Impact of National Cultural Differences on Nurses' Acceptance of Hospital Information Systems.

    PubMed

    Lin, Hsien-Cheng

    2015-06-01

    This study aims to explore the influence of national cultural differences on nurses' perceptions of their acceptance of hospital information systems. This study uses the perspective of Technology Acceptance Model; national cultural differences in terms of masculinity/femininity, individualism/collectivism, power distance, and uncertainty avoidance are incorporated into the Technology Acceptance Model as moderators, whereas time orientation is a control variable on hospital information system acceptance. A quantitative research design was used in this study; 261 participants, US and Taiwan RNs, all had hospital information system experience. Data were collected from November 2013 to February 2014 and analyzed using a t test to compare the coefficients for each moderator. The results show that individualism/collectivism, power distance, and uncertainty avoidance all exhibit significant difference on hospital information system acceptance; however, both masculinity/femininity and time orientation factors did not show significance. This study verifies that national cultural differences have significant influence on nurses' behavioral intention to use hospital information systems. Therefore, hospital information system providers should emphasize the way in which to integrate different technological functions to meet the needs of nurses from various cultural backgrounds.

  13. Modelling and pathway identification involving the transport mechanism of a complex metabolic system in batch culture

    NASA Astrophysics Data System (ADS)

    Yuan, Jinlong; Zhang, Xu; Zhu, Xi; Feng, Enmin; Yin, Hongchao; Xiu, Zhilong

    2014-06-01

    The bio-dissimilation of glycerol to 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae (K. pneumoniae) can be characterized by a complex metabolic system of interactions among biochemical fluxes, metabolic compounds, key enzymes and genetic regulation. In this paper, in consideration of the fact that the transport ways of 1,3-PD and glycerol with different weights across cell membrane are still unclear in batch culture, we consider 121 possible metabolic pathways and establish a novel mathematical model which is represented by a complex metabolic system. Taking into account the difficulty in accurately measuring the concentration of intracellular substances and the absence of equilibrium point for the metabolic system of batch culture, the novel approach used here is to define quantitatively biological robustness of the intracellular substance concentrations for the overall process of batch culture. To determine the most possible metabolic pathway, we take the defined biological robustness as cost function and establish an identification model, in which 1452 system parameters and 484 pathway parameters are involved. Simultaneously, the identification model is subject to the metabolic system, continuous state constraints and parameter constraints. As such, solving the identification model by a serial program is a very complicated task. We propose a parallel migration particle swarm optimization algorithm (MPSO) capable of solving the identification model in conjunction with the constraint transcription and smoothing approximation techniques. Numerical results show that the most possible metabolic pathway and the corresponding metabolic system can reasonably describe the process of batch culture.

  14. 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).

  15. Laser light scattering as a probe of fractal colloid aggregates

    NASA Technical Reports Server (NTRS)

    Weitz, David A.; Lin, M. Y.

    1989-01-01

    The extensive use of laser light scattering is reviewed, both static and dynamic, in the study of colloid aggregation. Static light scattering enables the study of the fractal structure of the aggregates, while dynamic light scattering enables the study of aggregation kinetics. In addition, both techniques can be combined to demonstrate the universality of the aggregation process. Colloidal aggregates are now well understood and therefore represent an excellent experimental system to use in the study of the physical properties of fractal objects. However, the ultimate size of fractal aggregates is fundamentally limited by gravitational acceleration which will destroy the fractal structure as the size of the aggregates increases. This represents a great opportunity for spaceborne experimentation, where the reduced g will enable the growth of fractal structures of sufficient size for many interesting studies of their physical properties.

  16. Revised culture-based system for identification of Malassezia species.

    PubMed

    Kaneko, Takamasa; Makimura, Koichi; Abe, Michiko; Shiota, Ryoko; Nakamura, Yuka; Kano, Rui; Hasegawa, Atsuhiko; Sugita, Takashi; Shibuya, Shuichi; Watanabe, Shinichi; Yamaguchi, Hideyo; Abe, Shigeru; Okamura, Noboru

    2007-11-01

    Forty-six strains of Malassezia spp. with atypical biochemical features were isolated from 366 fresh clinical isolates from human subjects and dogs. Isolates obtained in this study included 2 (4.7%) lipid-dependent M. pachydermatis isolates; 1 (2.4%) precipitate-producing and 6 (14.6%) non-polyethoxylated castor oil (Cremophor EL)-assimilating M. furfur isolates; and 37 (34.3%) M. slooffiae isolates that were esculin hydrolyzing, 17 (15.7%) that were non-tolerant of growth at 40 degrees C, and 2 (1.9%) that assimilated polyethoxylated castor oil. Although their colony morphologies and sizes were characteristic on CHROMagar Malassezia medium (CHROM), all strains of M. furfur developed large pale pink and wrinkled colonies, and all strains of M. slooffiae developed small (<1 mm) pale pink colonies on CHROM. These atypical strains were distinguishable by the appearance of their colonies grown on CHROM. Three clinically important Malassezia species, M. globosa, M. restricta, and M. furfur, were correctly identified by their biochemical characteristics and colony morphologies. The results presented here indicate that our proposed identification system will be useful as a routine tool for the identification of clinically important Malassezia species in clinical laboratories. PMID:17881545

  17. A 3D modeling and measurement system for cultural heritage preservation

    NASA Astrophysics Data System (ADS)

    Du, Guoguang; Zhou, Mingquan; Ren, Pu; Shui, Wuyang; Zhou, Pengbo; Wu, Zhongke

    2015-07-01

    Cultural Heritage reflects the human production, life style and environmental conditions of various historical periods. It exists as one of the major national carriers of national history and culture. In order to do better protection and utilization for these cultural heritages, a system of three-dimensional (3D) reconstruction and statistical measurement is proposed in this paper. The system solves the problems of cultural heritage's data storage, measurement and analysis. Firstly, for the high precision modeling and measurement problems, range data registration and integration algorithm used to achieve high precision 3D reconstruction. Secondly, multi-view stereo reconstruction method is used to solve the problem of rapid reconstruction by procedures such as the original image data pre-processing, camera calibration, point cloud modeling. At last, the artifacts' measure underlying database is established by calculating the measurements of the 3D model's surface. These measurements contain Euclidean distance between the points on the surface, geodesic distance between the points, normal and curvature in each point, superficial area of a region, volume of model's part and some other measurements. These measurements provide a basis for carrying out information mining of cultural heritage. The system has been applied to the applications of 3D modeling, data measurement of the Terracotta Warriors relics, Tibetan architecture and some other relics.

  18. Evaluation of mono or mixed cultures of lactic acid bacteria in type II sourdough system.

    PubMed

    Ekinci, Raci; Şimşek, Ömer; Küçükçuban, Ayca; Nas, Sebahattin

    2016-01-01

    The aim of this study was to evaluate the use of mono and mixed lactic acid bacteria (LAB) cultures to determine suitable LAB combinations for a type II sourdough system. In this context, previously isolated sourdough LAB strains with antimicrobial activity, which included Lactobacillus plantarum PFC22, Lactobacillus brevis PFC31, Pediococcus acidilactici PFC38, and Lactobacillus sanfranciscensis PFC80, were used as mono or mixed culture combinations in a fermentation system to produce type II sourdough, and subsequently in bread dough production. Compared to the monoculture fermentation of dough, the use of mixed cultures shortened the adaptation period by half. In addition, the use of mixed cultures ensured higher microbial viability, and enhanced the fruity flavor during bread dough production. It was determined that the combination of L. plantarum PFC22 + P. acidilactici PFC38 + L. sanfranciscensis PFC80 is a promising culture mixture that can be used in the production of type II sourdough systems, and that may also contribute to an increase in metabolic activity during bread production process.

  19. Long-term culture system for selective growth of human B-cell progenitors.

    PubMed Central

    Rawlings, D J; Quan, S G; Kato, R M; Witte, O N

    1995-01-01

    We describe a simple reproducible system for enrichment and long-term culture of human B-cell progenitors. Enriched CD34+ cord blood mononuclear cells are seeded onto a murine stromal cell line to establish a biphasic culture system. These cultures are characterized by transient growth of myeloid cells followed by outgrowth of cells highly enriched for early B-cell progenitors. Cultures consisting of > 90% early B-lineage cells [expressing CD10, CD19, CD38, and CD45 but lacking CD20, CD22, CD23, and surface IgM] are maintained for > 12 weeks without growth factor addition. Cells remain predominantly germ line at the immunoglobulin locus and express only low levels of cytoplasmic mu chain, terminal deoxynucleotidyltransferase, and recombination-activating gene 1 product. They are unresponsive to the pre-B-cell growth factors interleukin 7 or stem cell factor, or both, suggesting that growth support is provided by a cross-reactive murine stromal cell factor. Cultured B-cell progenitors are generated in large numbers ( > 10(8) cells from a typical cord blood specimen) suitable for use in biochemical analysis and gene-transfer studies. This system should be useful for study of normal and abnormal early human B-lymphopoiesis. Images Fig. 2 Fig. 3 Fig. 4 PMID:7533295

  20. Three-dimensional cell culturing by magnetic levitation.

    PubMed

    Haisler, William L; Timm, David M; Gage, Jacob A; Tseng, Hubert; Killian, T C; Souza, Glauco R

    2013-10-01

    Recently, biomedical research has moved toward cell culture in three dimensions to better recapitulate native cellular environments. This protocol describes one method for 3D culture, the magnetic levitation method (MLM), in which cells bind with a magnetic nanoparticle assembly overnight to render them magnetic. When resuspended in medium, an external magnetic field levitates and concentrates cells at the air-liquid interface, where they aggregate to form larger 3D cultures. The resulting cultures are dense, can synthesize extracellular matrix (ECM) and can be analyzed similarly to the other culture systems using techniques such as immunohistochemical analysis (IHC), western blotting and other biochemical assays. This protocol details the MLM and other associated techniques (cell culture, imaging and IHC) adapted for the MLM. The MLM requires 45 min of working time over 2 d to create 3D cultures that can be cultured in the long term (>7 d). PMID:24030442

  1. Recombinant Human Semenogelin-1 (Sg1) and Sg1 (1-159) form Detergent Stable Amyloid like Aggregates in vitro.

    PubMed

    Sharma, Neetu; Vishwanath, S; Patel, Basant K

    2016-01-01

    Senile seminal vesicle amyloidosis (SSVA) is associated with deposition of semenogelin-1 (Sg1) protein aggregates in seminal vesicles that may manifest as hematospermia. Sg1 is the predominant protein that entraps spermatozoa which are freed upon fragmentation of Sg1 by the protease prostate specific antigen (PSA), post semen release. Certain small peptide fragments of Sg1 have been reported to form amyloid aggregates in vitro that can enhance HIV infectivity to cell cultures. However, the amyloid deposits in the seminal vesicles are expected to be that of the full length Sg1, as PSA is encountered downstream. So far, amyloid forming ability of full length Sg1 has not been established in vitro. Here, we examined the amyloidogenicity of full length Sg1 and a large fragment Sg1 (1-159), using recombinant proteins and tested if Zinc has any effect on their aggregation. Levels of Zinc, which is essential for health of male reproductive system, gradually decline with age. We succeeded in forming amyloid-like aggregates of Sg1 full length and Sg1 (1-159) fragment showing detergent stability and found that presence of Zn2+ substantially inhibits their amyloid aggregation in vitro. Possibly, high Zn2+ found in seminal plasma of young individuals may have preventive role against aggregation of Sg1 in seminal vesicles.

  2. Simulations of kinetically irreversible protein aggregate structure.

    PubMed Central

    Patro, S Y; Przybycien, T M

    1994-01-01

    We have simulated the structure of kinetically irreversible protein aggregates in two-dimensional space using a lattice-based Monte-Carlo routine. Our model specifically accounts for the intermolecular interactions between hydrophobic and hydrophilic protein surfaces and a polar solvent. The simulations provide information about the aggregate density, the types of inter-monomer contacts and solvent content within the aggregates, the type and extent of solvent exposed perimeter, and the short- and long-range order all as a function of (i) the extent of monomer hydrophobic surface area and its distribution on the model protein surface and (ii) the magnitude of the hydrophobic-hydrophobic contact energy. An increase in the extent of monomer hydrophobic surface area resulted in increased aggregate densities with concomitant decreased system free energies. These effects are accompanied by increases in the number of hydrophobic-hydrophobic contacts and decreases in the solvent-exposed hydrophobic surface area of the aggregates. Grouping monomer hydrophobic surfaces in a single contiguous stretch resulted in lower aggregate densities and lower short range order. More favorable hydrophobic-hydrophobic contact energies produced structures with higher densities but the number of unfavorable protein-protein contacts was also observed to increase; greater configurational entropy produced the opposite effect. Properties predicted by our model are in good qualitative agreement with available experimental observations. Images FIGURE 6 FIGURE 13 PMID:8061184

  3. An energy landscape approach to protein aggregation

    NASA Astrophysics Data System (ADS)

    Buell, Alexander; Knowles, Tuomas

    2012-02-01

    Protein aggregation into ordered fibrillar structures is the hallmark of a class of diseases, the most prominent examples of which are Alzheimer's and Parkinson's disease. Recent results (e.g. Baldwin et al. J. Am. Chem. Soc. 2011) suggest that the aggregated state of a protein is in many cases thermodynamically more stable than the soluble state. Therefore the solubility of proteins in a cellular context appears to be to a large extent under kinetic control. Here, we first present a conceptual framework for the description of protein aggregation ( see AK Buell et al., Phys. Rev. Lett. 2010) that is an extension to the generally accepted energy landscape model for protein folding. Then we apply this model to analyse and interpret a large set of experimental data on the kinetics of protein aggregation, acquired mainly with a novel biosensing approach (see TPJK Knowles et al, Proc. Nat. Acad. Sc. 2007). We show how for example the effect of sequence modifications on the kinetics and thermodynamics of human lysozyme aggregation can be understood and quantified (see AK Buell et al., J. Am. Chem. Soc. 2011). These results have important implications for therapeutic strategies against protein aggregation disorders, in this case lysozyme systemic amyloidosis.

  4. Multi-scale interactions in Dictyostelium discoideum aggregation

    NASA Astrophysics Data System (ADS)

    Dixon, James A.; Kelty-Stephen, Damian G.

    2012-12-01

    Cellular aggregation is essential for a wide range of phenomena in developmental biology, and a crucial event in the life-cycle of Dictyostelium discoideum. The current manuscript presents an analysis of multi-scale interactions involved in D. discoideum aggregation and non-aggregation events. The multi-scale fractal dimensions of a sequence of microscope images were used to estimate changing structure at different spatial scales. Three regions showing aggregation and three showing non-aggregation were considered. The results showed that both aggregation and non-aggregation regions were strongly multi-fractal. Analyses of the over-time relationships among nine scales of the generalized dimension, D(q), were conducted using vector autoregression and vector error-correction models. Both types of regions showed evidence that across-scale interactions serve to maintain the equilibrium of the system. Aggregation and non-aggregation regions also showed different patterns of effects of individual scales on other scales. Specifically, aggregation regions showed greater effects of both the smallest and largest scales on the smaller scale structures. The results suggest that multi-scale interactions are responsible for maintaining and altering the cellular structures during aggregation.

  5. Reconstituted Thymus Organ Culture.

    PubMed

    Deng, Zimu; Liu, Haifeng; Rui, Jinxiu; Liu, Xiaolong

    2016-01-01

    Reconstituted thymus organ culture is based on fetal thymus organ culture (FTOC). Purified thymocyte populations, from genetically modified mice or even from other species, are cultured in vitro with thymic lobes depleted of their endogenous thymocytes (by 2'-deoxyguanosine treatment) to form a new thymus. This potent and timesaving method is distinct from FTOC, which assesses development of unmodified thymic lobes, and reaggregate thymic organ culture, in which epithelial cells are separately purified before being aggregated with thymocytes.

  6. Assessment of carotenoid production by Dunaliella salina in different culture systems and operation regimes.

    PubMed

    Prieto, Ana; Pedro Cañavate, J; García-González, Mercedes

    2011-01-20

    The effect of operation regime and culture system on carotenoid productivity by the halotolerant alga Dunaliella salina has been analyzed. Operation strategies tested included batch and semi continuous regime, as well as a two-stage approach run simultaneously in both, open tanks and closed reactor. The best results were obtained with the closed tubular photobioreactor. The highest carotenoid production (328.8 mg carotenoid l⁻¹ culture per month) was achieved with this culture system operated following the two-stage strategy. Also, closed tubular photobioreactor provided the highest carotenoid contents (10% of dry weight) in Dunaliella biomass and β-carotene abundance (90% of total carotenoids) as well as the highest 9-cis to all-trans β-carotene isomer ratio (1.5 at sunrise).

  7. A pneumatic pressure-driven multi-throughput microfluidic circulation culture system.

    PubMed

    Satoh, T; Narazaki, G; Sugita, R; Kobayashi, H; Sugiura, S; Kanamori, T

    2016-06-21

    Here, we report a pneumatic pressure-driven microfluidic device capable of multi-throughput medium circulation culture. The circulation culture system has the following advantages for application in drug discovery: (i) simultaneous operation of multiple circulation units, (ii) use of a small amount of circulating medium (3.5 mL), (iii) pipette-friendly liquid handling, and (iv) a detachable interface with pneumatic pressure lines via sterile air-vent filters. The microfluidic device contains three independent circulation culture units, in which human umbilical vein endothelial cells (HUVECs) were cultured under physiological shear stress induced by circulation of the medium. Circulation of the medium in the three culture units was generated by programmed sequentially applied pressure from two pressure-control lines. HUVECs cultured in the microfluidic device were aligned under a one-way circulating flow with a shear stress of 10 dyn cm(-2); they exhibited a randomly ordered alignment under no shear stress and under reciprocating flow with a shear stress of 10 dyn cm(-2). We also observed 2.8- to 4.9-fold increases in expression of the mRNAs of endothelial nitric oxide synthase and thrombomodulin under one-way circulating flow with a shear stress of 10 dyn cm(-2) compared with conditions of no shear stress or reciprocating flow. PMID:27229626

  8. Off-flavor characterization and depuration in Atlantic salmon cultured to food-size within closed-containment systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Atlantic salmon are typically cultured in marine net pens. However, technological advancements in recirculating aquaculture systems have increased the feasibility of culturing Atlantic salmon in land-based systems. One problem encountered when fish are harvested from recirculating systems is the pre...

  9. Three-dimensional hydrogel cell culture systems for modeling neural tissue

    NASA Astrophysics Data System (ADS)

    Frampton, John

    Two-dimensional (2-D) neural cell culture systems have served as physiological models for understanding the cellular and molecular events that underlie responses to physical and chemical stimuli, control sensory and motor function, and lead to the development of neurological diseases. However, the development of three-dimensional (3-D) cell culture systems will be essential for the advancement of experimental research in a variety of fields including tissue engineering, chemical transport and delivery, cell growth, and cell-cell communication. In 3-D cell culture, cells are provided with an environment similar to tissue, in which they are surrounded on all sides by other cells, structural molecules and adhesion ligands. Cells grown in 3-D culture systems display morphologies and functions more similar to those observed in vivo, and can be cultured in such a way as to recapitulate the structural organization and biological properties of tissue. This thesis describes a hydrogel-based culture system, capable of supporting the growth and function of several neural cell types in 3-D. Alginate hydrogels were characterized in terms of their biomechanical and biochemical properties and were functionalized by covalent attachment of whole proteins and peptide epitopes. Methods were developed for rapid cross-linking of alginate hydrogels, thus permitting the incorporation of cells into 3-D scaffolds without adversely affecting cell viability or function. A variety of neural cell types were tested including astrocytes, microglia, and neurons. Cells remained viable and functional for longer than two weeks in culture and displayed process outgrowth in 3-D. Cell constructs were created that varied in cell density, type and organization, providing experimental flexibility for studying cell interactions and behavior. In one set of experiments, 3-D glial-endothelial cell co-cultures were used to model blood-brain barrier (BBB) structure and function. This co-culture system was

  10. Comparison of defined culture systems for feeder cell free propagation of human embryonic stem cells

    PubMed Central

    Akopian, Veronika; Beil, Stephen; Benvenisty, Nissim; Brehm, Jennifer; Christie, Megan; Ford, Angela; Fox, Victoria; Gokhale, Paul J.; Healy, Lyn; Holm, Frida; Hovatta, Outi; Knowles, Barbara B.; Ludwig, Tenneille E.; McKay, Ronald D. G.; Miyazaki, Takamichi; Nakatsuji, Norio; Oh, Steve K. W.; Pera, Martin F.; Rossant, Janet; Stacey, Glyn N.; Suemori, Hirofumi

    2010-01-01

    There are many reports of defined culture systems for the propagation of human embryonic stem cells in the absence of feeder cell support, but no previous study has undertaken a multi-laboratory comparison of these diverse methodologies. In this study, five separate laboratories, each with experience in human embryonic stem cell culture, used a panel of ten embryonic stem cell lines (including WA09 as an index cell line common to all laboratories) to assess eight cell culture methods, with propagation in the presence of Knockout Serum Replacer, FGF-2, and mouse embryonic fibroblast feeder cell layers serving as a positive control. The cultures were assessed for up to ten passages for attachment, death, and differentiated morphology by phase contrast microscopy, for growth by serial cell counts, and for maintenance of stem cell surface marker expression by flow cytometry. Of the eight culture systems, only the control and those based on two commercial media, mTeSR1 and STEMPRO, supported maintenance of most cell lines for ten passages. Cultures grown in the remaining media failed before this point due to lack of attachment, cell death, or overt cell differentiation. Possible explanations for relative success of the commercial formulations in this study, and the lack of success with other formulations from academic groups compared to previously published results, include: the complex combination of growth factors present in the commercial preparations; improved development, manufacture, and quality control in the commercial products; differences in epigenetic adaptation to culture in vitro between different ES cell lines grown in different laboratories. PMID:20186512

  11. A primary culture system of mouse thick ascending limb cells with preserved function and uromodulin processing.

    PubMed

    Glaudemans, Bob; Terryn, Sara; Gölz, Nadine; Brunati, Martina; Cattaneo, Angela; Bachi, Angela; Al-Qusairi, Lama; Ziegler, Urs; Staub, Olivier; Rampoldi, Luca; Devuyst, Olivier

    2014-02-01

    The epithelial cells lining the thick ascending limb (TAL) of the loop of Henle perform essential transport processes and secrete uromodulin, the most abundant protein in normal urine. The lack of differentiated cell culture systems has hampered studies of TAL functions. Here, we report a method to generate differentiated primary cultures of TAL cells, developed from microdissected tubules obtained in mouse kidneys. The TAL tubules cultured on permeable filters formed polarized confluent monolayers in ∼12 days. The TAL cells remain differentiated and express functional markers such as uromodulin, NKCC2, and ROMK at the apical membrane. Electrophysiological measurements on primary TAL monolayers showed a lumen-positive transepithelial potential (+9.4 ± 0.8 mV/cm(2)) and transepithelial resistance similar to that recorded in vivo. The transepithelial potential is abolished by apical bumetanide and in primary cultures obtained from ROMK knockout mice. The processing, maturation and apical secretion of uromodulin by primary TAL cells is identical to that observed in vivo. The primary TAL cells respond appropriately to hypoxia, hypertonicity, and stimulation by desmopressin, and they can be transfected. The establishment of this primary culture system will allow the investigation of TAL cells obtained from genetically modified mouse models, providing a critical tool for understanding the role of that segment in health and disease. PMID:23887378

  12. Co-culture systems and technologies: taking synthetic biology to the next level.

    PubMed

    Goers, Lisa; Freemont, Paul; Polizzi, Karen M

    2014-07-01

    Co-culture techniques find myriad applications in biology for studying natural or synthetic interactions between cell populations. Such techniques are of great importance in synthetic biology, as multi-species cell consortia and other natural or synthetic ecology systems are widely seen to hold enormous potential for foundational research as well as novel industrial, medical and environmental applications with many proof-of-principle studies in recent years. What is needed for co-cultures to fulfil their potential? Cell-cell interactions in co-cultures are strongly influenced by the extracellular environment, which is determined by the experimental set-up, which therefore needs to be given careful consideration. An overview of existing experimental and theoretical co-culture set-ups in synthetic biology and adjacent fields is given here, and challenges and opportunities involved in such experiments are discussed. Greater focus on foundational technology developments for co-cultures is needed for many synthetic biology systems to realize their potential in both applications and answering biological questions. PMID:24829281

  13. Mini-scale bioprocessing systems for highly parallel animal cell cultures.

    PubMed

    Kim, Beum Jun; Diao, Jinpian; Shuler, Michael L

    2012-01-01

    Animal cells have been used extensively in therapeutic protein production. The growth of animal cells and the expression of therapeutic proteins are highly dependent on the culturing environments. A large number of experimental permutations need to be explored to identify the optimal culturing conditions. Miniaturized bioreactors are well suited for such tasks as they offer high-throughput parallel operation and reduce cost of reagents. They can also be automated and be coupled to downstream analytical units for online measurements of culture products. This review summarizes the current status of miniaturized bioreactors for animal cell cultivation based on the design categories: microtiter plates, flasks, stirred tank reactors, novel designs with active mixing, and microfluidic cell culture devices. We compare cell density and product titer, for batch or fed-batch modes for each system. Monitoring/controlling devices for engineering parameters such as pH, dissolved oxygen, and dissolved carbon dioxide, which could be applied to such systems, are summarized. Finally, mini-scale tools for process performance evaluation for animal cell cultures are discussed: total cell density, cell viability, product titer and quality, substrates, and metabolites profiles. PMID:22522970

  14. Co-culture systems and technologies: taking synthetic biology to the next level.

    PubMed

    Goers, Lisa; Freemont, Paul; Polizzi, Karen M

    2014-07-01

    Co-culture techniques find myriad applications in biology for studying natural or synthetic interactions between cell populations. Such techniques are of great importance in synthetic biology, as multi-species cell consortia and other natural or synthetic ecology systems are widely seen to hold enormous potential for foundational research as well as novel industrial, medical and environmental applications with many proof-of-principle studies in recent years. What is needed for co-cultures to fulfil their potential? Cell-cell interactions in co-cultures are strongly influenced by the extracellular environment, which is determined by the experimental set-up, which therefore needs to be given careful consideration. An overview of existing experimental and theoretical co-culture set-ups in synthetic biology and adjacent fields is given here, and challenges and opportunities involved in such experiments are discussed. Greater focus on foundational technology developments for co-cultures is needed for many synthetic biology systems to realize their potential in both applications and answering biological questions.

  15. The Problem of Cultural Fit--What Can We Learn from Borrowing the German Dual System?

    ERIC Educational Resources Information Center

    Lewis, Theodore

    2007-01-01

    Culture impedes educational transactions between developed countries, and is often an area of tension when developing countries try to borrow models, or have models imposed upon them. This article uses the German Dual System as a case for examining issues surrounding the adaptation of borrowed models. Since attempts at borrowing models can fail…

  16. Development of Quality Assurance System in Culture and Nation Character Education in Primary Education in Indonesia

    ERIC Educational Resources Information Center

    Susilana, Rudi; Asra

    2013-01-01

    The purpose of national education is to develop skills and build dignified national character and civilization in educating nation life (Act No. 20, 2003). The paper describes a system of quality assurance in culture and character education in primary education. This study employs the six sigma model which consists of the formula DMAIC (Define,…

  17. From the World-Systems Perspective to Institutional World History: Culture and Economy in Global Theory.

    ERIC Educational Resources Information Center

    Benton, Lauren

    1996-01-01

    Summarizes critical attacks on Immanuel Wallerstein's World Systems approach to history and offers new critical evaluations. Wallerstein argued that an emerging capitalist world economy dominated politics and history from the 16th century to the present. Defines two new approaches, institutional analysis and post colonial cultural theory, that…

  18. The Learning Transfer System Inventory (LTSI) in Ukraine: The Cross-Cultural Validation of the Instrument

    ERIC Educational Resources Information Center

    Yamkovenko, Bogdan V.; Holton, Elwood, III; Bates, R. A.

    2007-01-01

    Purpose: The purpose of this research is to expand cross-cultural research and validate the Learning Transfer System Inventory in Ukraine. The researchers seek to translate the LTSI into Ukrainian and investigate the internal structure of this translated version of the questionnaire. Design/methodology/approach: The LTSI is translated into…

  19. Organizing the Baby Boomer Construct: An Exploration of Marketing, Social Systems, and Culture

    ERIC Educational Resources Information Center

    Lipschultz, Jeremy H.; Hilt, Michael L.; Reilly, Hugh J.

    2007-01-01

    Baby boomer trends are applied in the development of a conceptual framework that offers a social systems and cultural model for future studies. While there has been considerable recent attention paid to baby boomers, the studies lack a coherent theoretical base that would allow for more advanced and continuing research. Aging baby boomers heading…

  20. Raising Cultural Self-Efficacy among Faculty and Staff of a Private Native Hawaiian School System

    ERIC Educational Resources Information Center

    Fong, Randie Kamuela

    2012-01-01

    The Hawaiian cultural revitalization movement in Hawai`i is an important driver for many Hawaiian organizations as well as educational institutions that serve Native Hawaiians. One such organization is Kamehameha Schools, a private school system founded and endowed by Princess Bernice Pauahi Bishop in 1887 to educate Native Hawaiian children. From…

  1. Improving Achievement for Linguistically and Culturally Diverse Learners through an Inquiry-Based Earth Systems Curriculum

    ERIC Educational Resources Information Center

    Lambert, Julie; Ariza, Eileen N. Whelan

    2008-01-01

    This report describes an inquiry-based Earth systems curriculum and strategies for teaching diverse students, which were embedded in the curriculum. The curriculum was implemented with 5th-grade students with varied linguistic, cultural, and socioeconomic backgrounds in five schools in a large, southeastern U.S., urban school district. At the end…

  2. Cultural Influences and Corporate Decision Making: The Humanities/Information Systems Partnership.

    ERIC Educational Resources Information Center

    Skovira, Robert J.

    Robert Morris College received a national Endowment for the Humanities grant to create a faculty study project to internationalize the humanities curriculum. The Humanities can play a role in building the cultural contexts and contributing to a deeper understanding of information-based corporate decision making in Information Systems courses,…

  3. Spearmint plantlet culture system as a means to study secondary metabolism in vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The production of phytochemicals in vitro has been obtained from a variety of tissue types and organs. A plantlet culture system offers a means to study whole plant growth and development in a miniature scale and their corresponding phytochemical production. Plantlets resemble their in vivo counte...

  4. Social-Cultural-Historical Contradictions in an L2 Listening Lesson: A Joint Activity System Analysis

    ERIC Educational Resources Information Center

    Cross, Jeremy

    2011-01-01

    Informed and inspired by neo-Vygotskian theory, this article outlines a study exploiting a contemporary conceptualization of Wells's (2002) joint activity system model as an exploratory framework for examining and depicting the social-cultural-historical contradictions in second-language (L2) learners' joint activity. The participants were a pair…

  5. Improving Hospital Quality and Patient Safety an Examination of Organizational Culture and Information Systems

    ERIC Educational Resources Information Center

    Gardner, John Wallace

    2012-01-01

    This dissertation examines the effects of safety culture, including operational climate and practices, as well as the adoption and use of information systems for delivering high quality healthcare and improved patient experience. Chapter 2 studies the influence of both general and outcome-specific hospital climate and quality practices on process…

  6. National Contexts Influencing Principals' Time Use and Allocation: Economic Development, Societal Culture, and Educational System

    ERIC Educational Resources Information Center

    Lee, Moosung; Hallinger, Philip

    2012-01-01

    This study examines the impact of macro-context factors on the behavior of school principals. More specifically, the article illuminates how a nation's level of economic development, societal culture, and educational system influence the amount of time principals devote to their job role and shape their allocation of time to instructional…

  7. Cultural Competence, Systems of Care, and Students with Emotional and Behavioral Challenges

    ERIC Educational Resources Information Center

    Meyer, Lakeisha D.; Anderson, Jeffrey A.; McQueen, Kand

    2013-01-01

    For youth with emotional and behavioral challenges, there is a trend of minority overrepresentation in restrictive settings. "System of care" refers to an approach that emphasizes cultural competence and providing services in the least restrictive setting. This study investigated the relationship between placement restrictiveness,…

  8. Cultural Capital in East Asian Educational Systems: The Case of Japan

    ERIC Educational Resources Information Center

    Yamamoto, Yoko; Brinton, Mary C.

    2010-01-01

    Cultural capital has been an important but often elusive concept in the study of educational processes and social class reproduction. The authors suggest that this is partly because a country's educational system and ways of evaluating students at different educational transitions set the context for the mechanisms through which embodied and…

  9. Culture characteristics of the atmospheric and room temperature plasma-mutated Spirulina platensis mutants in CO2 aeration culture system for biomass production.

    PubMed

    Tan, Yinyee; Fang, Mingyue; Jin, Lihua; Zhang, Chong; Li, He-Ping; Xing, Xin-Hui

    2015-10-01

    For biomass production of Spirulina platensis as feedstock of fermentation, the culture characteristics of three typical mutants of 3-A10, 3-B2 and 4-B3 generated by atmospheric and room temperature plasmas (ARTP) mutagenesis were systematically studied by using CO2 aeration culture system and compared with the wild strain. The specific growth rate of wild strain in the pure air aeration culture system exhibited a 76.2% increase compared with static culture, while the specific growth rates of the 3-A10, 3-B2 and 4-B3 in pure air aeration culture system were increased by 114.4%, 95.9% and 88.2% compared with their static cultures. Compared with static culture, the carbohydrate contents of wild strain, 3-A10, 3-B2 and 4-B3 in pure air aeration culture system dropped plainly by 51.0%, 79.3%, 85.5% and 26.1%. Increase of CO2 concentration enhanced carbohydrate content and productivity. Based on the carbohydrate productivity, the optimal inlet of CO2 concentration in aeration culture was determined to be 12% (v/v). Under this condition, 3-B2 exhibited the highest carbohydrate content (30.7%), CO2 fixation rate (0.120gCO2·g(-1)·d(-1)) and higher growth rate (0.093 g L(-1)·d(-1)), while 3-A10 showed the highest growth rate (0.118 g L(-1)·d(-1)) and higher CO2 fixation rate (0.117gCO2·g(-1)·d(-1)) but low carbohydrate content (24.5%), and 4-B3 showed the highest chlorophyll (Chl) content (3.82 mg·g(-1)). The most outstanding mutant by static culture in terms of growth rate and carbohydrate productivity (3-B2), was also demonstrated by CO2 aeration culture system. This study revealed that the ARTP mutagenesis could generate the S. platensis mutants suitable for CO2 aeration culture aiming at biomass production. PMID:25795571

  10. Culture characteristics of the atmospheric and room temperature plasma-mutated Spirulina platensis mutants in CO2 aeration culture system for biomass production.

    PubMed

    Tan, Yinyee; Fang, Mingyue; Jin, Lihua; Zhang, Chong; Li, He-Ping; Xing, Xin-Hui

    2015-10-01

    For biomass production of Spirulina platensis as feedstock of fermentation, the culture characteristics of three typical mutants of 3-A10, 3-B2 and 4-B3 generated by atmospheric and room temperature plasmas (ARTP) mutagenesis were systematically studied by using CO2 aeration culture system and compared with the wild strain. The specific growth rate of wild strain in the pure air aeration culture system exhibited a 76.2% increase compared with static culture, while the specific growth rates of the 3-A10, 3-B2 and 4-B3 in pure air aeration culture system were increased by 114.4%, 95.9% and 88.2% compared with their static cultures. Compared with static culture, the carbohydrate contents of wild strain, 3-A10, 3-B2 and 4-B3 in pure air aeration culture system dropped plainly by 51.0%, 79.3%, 85.5% and 26.1%. Increase of CO2 concentration enhanced carbohydrate content and productivity. Based on the carbohydrate productivity, the optimal inlet of CO2 concentration in aeration culture was determined to be 12% (v/v). Under this condition, 3-B2 exhibited the highest carbohydrate content (30.7%), CO2 fixation rate (0.120gCO2·g(-1)·d(-1)) and higher growth rate (0.093 g L(-1)·d(-1)), while 3-A10 showed the highest growth rate (0.118 g L(-1)·d(-1)) and higher CO2 fixation rate (0.117gCO2·g(-1)·d(-1)) but low carbohydrate content (24.5%), and 4-B3 showed the highest chlorophyll (Chl) content (3.82 mg·g(-1)). The most outstanding mutant by static culture in terms of growth rate and carbohydrate productivity (3-B2), was also demonstrated by CO2 aeration culture system. This study revealed that the ARTP mutagenesis could generate the S. platensis mutants suitable for CO2 aeration culture aiming at biomass production.

  11. Emerin expression in tubular aggregates.

    PubMed

    Manta, Panagiota; Terzis, Gerasimos; Papadimitriou, Constantinos; Kontou, Chrysanthi; Vassilopoulos, Demetris

    2004-06-01

    Emerin is an inner nuclear membrane protein that is mutated or not expressed in patients with X-linked Emery-Dreifuss muscular dystrophy (X-EDMD/EMD). Cytoplasmic localization of emerin in cultured cells or tissues has been reported, although this remains a controversial issue. Tubular aggregates (TAs) are pathological structures seen in the sarcoplasm of human skeletal muscle fibers in various disorders. The TAs derive from the sarcoplasmic reticulum (SR) and represent, probably, an adaptive response of the SR to various insults to the muscle fibers. In the present study, we present immunohistochemical evidence of emerin expression in TAs. Muscle biopsies with tubular aggregates from four male, unrelated patients were studied. The percentage of muscle fibers containing TAs varied between 5 and 20%. Routine histochemistry revealed intense reaction of TAs with NADH-TR, AMPDA, and NSE, but not with COX, SDH, myosin ATPase (pH 9.4, 4.3, 4.6), PAS, and Oil red O staining. Immunohistochemical study revealed strong immunostaining of TAs with antibodies against emerin and 7 SERCA2-ATPase. Immunostaining of TAs was also seen with antibodies against heat shock protein and dysferlin, but not with antibodies to lamin A, dystrophin, adhalin, beta, gamma, delta sarcoglycans, and merosin. These results suggest that emerin, an inner nuclear membrane protein, is present at the TAs. The interpretation and significance of this finding is discussed in relation to experimental data suggesting that normal emerin localization at the inner nuclear membrane depends on lamin A and mutations in the N-terminal domain of emerin cause mislocalization of the protein to the sarcoplasmic membranes.

  12. Quasi-elastic light scattering studies of native hepatic bile from the dog: comparison with aggregative behavior of model biliary lipid systems.

    PubMed

    Mazer, N A; Schurtenberg, P; Carey, M C; Preisig, R; Weigand, K; Känzig, W

    1984-04-24

    Using quasi-elastic light scattering ( QLS ), we have characterized the macromolecular components in hepatic bile obtained from the dog and compared these results with data from model bile solutions containing the bile salt (BS) sodium taurocholate (TC), egg lecithin (L), and cholesterol (Ch). Native bile samples were obtained by direct catheterization of the common bile duct in a previously cholecystectomized dog fitted with a Thomas duodenal cannula. Hepatic bile was sampled during three secretory states: (A) unstimulated "fasting" bile, (B) "stimulated" secretion during an intravenous TC infusion, and (C) "secretin-stimulated" secretion. All three samples had comparable molar ratios of L/BS (0.21 +/- 0.03) and Ch/L (0.027 +/- 0.006) but differed in the total lipid concentration (BS + L + Ch): (A) 13.1 +/- 0.8, (B) 6.7 +/- 0.8, and (C) 3.0 +/- 0.4 g/dL. From the QLS autocorrelation functions measured on samples B and C, three macromolecular components (denoted 1 alpha, 1 beta, and 2) were resolved. Component 1 alpha (hydrodynamic radius R1 alpha = 10 +/- 2 A) is comparable in size to the micellar aggregates of model systems. Component 1 beta (R1 beta = 67 +/- 7 A) appears to reflect an average of biliary proteins. Component 2 (R2 = 650 +/- 15 A) is a trace component whose size and sedimentation behavior are compatible with those of the canalicular membrane vesicles postulated to be present in bile [ Godfrey , P. P., Warner, M. J., & Coleman , R. (1981) Biochem. J. 196, 11]. Serial dilution of the B and C bile samples with Tris buffer (0.15 M NaCl, pH 8.0) showed a remarkable similarity in the behavior of the 1 alpha component as compared to the mean hydrodynamic radius Rh of similarly diluted model bile solutions. When a critical dilution factor, d gamma, is reached, Rh increases abruptly from approximately 30 to approximately 400 A. Above a second dilution factor, d alpha, it then decreases to a value of approximately 150 A. Similar results were obtained on

  13. 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.

  14. Recurrent amoebic gill infestation in rainbow trout cultured in a semiclosed water recirculation system

    USGS Publications Warehouse

    Noble, A.C.; Herman, R.L.; Noga, E.J.; Bullock, G.L.

    1997-01-01

    Five lots of commercially purchased juvenile rainbow trout Oncorhynchus mykiss (17-44 g) stocked in a continuous-production water recirculation system became infested with gilt amoebae. The amoebae were introduced into the recirculation system, as evidenced by their presence on gills of fish held in quarantine tanks. Based on their morphology, as seen in histological sections and by electron microscopy, the amoebae appeared to be more closely related to the family Cochliopodiidae than to other taxa of free living amoebae. Attempts to culture the amoebae in different media, at different temperatures of incubation, and in fish cell culture were not successful. Initial treatment of the recirculation system with formalin at 167 parts per million (ppm) for 1 h eliminated amoebae from the gills. Subsequent treatments of the entire system with formalin at 50-167 ppm reduced the intensity of further infestations.

  15. Tracking hypoxic signaling within encapsulated cell aggregates.

    PubMed

    Skiles, Matthew L; Sahai, Suchit; Blanchette, James O

    2011-01-01

    , is therefore reduced and limited by diffusion. This reduced oxygen availability may especially impact β-cells whose insulin secretory function is highly dependent on oxygen. Capsule composition and geometry will also impact diffusion rates and lengths for oxygen. Therefore, we also describe a technique for identifying hypoxic cells within our PEG capsules. Infection of the cells with a recombinant adenovirus allows for a fluorescent signal to be produced when intracellular hypoxia-inducible factor (HIF) pathways are activated. As HIFs are the primary regulators of the transcriptional response to hypoxia, they represent an ideal target marker for detection of hypoxic signaling. This approach allows for easy and rapid detection of hypoxic cells. Briefly, the adenovirus has the sequence for a red fluorescent protein (Ds Red DR from Clontech) under the control of a hypoxia-responsive element (HRE) trimer. Stabilization of HIF-1 by low oxygen conditions will drive transcription of the fluorescent protein (Figure 1). Additional details on the construction of this virus have been published previously. The virus is stored in 10% glycerol at -80° C as many 150 μL aliquots in 1.5 mL centrifuge tubes at a concentration of 3.4 x 10(10) pfu/mL. Previous studies in our lab have shown that MIN6 cells encapsulated as aggregates maintain their viability throughout 4 weeks of culture in 20% oxygen. MIN6 aggregates cultured at 2 or 1% oxygen showed both signs of necrotic cells (still about 85-90% viable) by staining with ethidium bromide as well as morphological changes relative to cells in 20% oxygen. The smooth spherical shape of the aggregates displayed at 20% was lost and aggregates appeared more like disorganized groups of cells. While the low oxygen stress does not cause a pronounced drop in viability, it is clearly impacting MIN6 aggregation and function as measured by glucose-stimulated insulin secretion. Western blot analysis of encapsulated cells in 20% and 1% oxygen also

  16. An aeroponic culture system for the study of root herbivory on Arabidopsis thaliana

    PubMed Central

    2011-01-01

    Background Plant defense against herbivory has been studied primarily in aerial tissues. However, complex defense mechanisms have evolved in all parts of the plant to combat herbivore attack and these mechanisms are likely to differ in the aerial and subterranean environment. Research investigating defense responses belowground has been hindered by experimental difficulties associated with the accessibility and quality of root tissue and the lack of bioassays using model plants with altered defense profiles. Results We have developed an aeroponic culture system based on a calcined clay substrate that allows insect herbivores to feed on plant roots while providing easy recovery of the root tissue. The culture method was validated by a root-herbivore system developed for Arabidopsis thaliana and the herbivore Bradysia spp. (fungus gnat). Arabidopsis root mass obtained from aeroponically grown plants was comparable to that from other culture systems, and the plants were morphologically normal. Bradysia larvae caused considerable root damage resulting in reduced root biomass and water absorption. After feeding on the aeroponically grown root tissue, the larvae pupated and emerged as adults. Root damage of mature plants cultivated in aeroponic substrate was compared to that of Arabidopsis seedlings grown in potting mix. Seedlings were notably more susceptible to Bradysia feeding than mature plants and showed decreased overall growth and survival rates. Conclusions A root-herbivore system consisting of Arabidopsis thaliana and larvae of the opportunistic herbivore Bradysia spp. has been established that mimics herbivory in the rhizosphere. Bradysia infestation of Arabidopsis grown in this culture system significantly affects plant performance. The culture method will allow simple profiling and in vivo functional analysis of root defenses such as chemical defense metabolites that are released in response to belowground insect attack. PMID:21392399

  17. Enhancing Therapeutic Efficacy through Designed Aggregation of Nanoparticles

    PubMed Central

    Sadhukha, Tanmoy; Wiedmann, Timothy Scott; Panyama, Jayanth

    2015-01-01

    Particle size is a key determinant of biological performance of sub-micron size delivery systems. Previous studies investigating the effect of particle size have primarily focused on well-dispersed nanoparticles. However, inorganic nanoparticles are prone to aggregation in biological environments. In our studies, we examined the consequence of aggregation on superparamagnetic iron oxide (SPIO) nanoparticle-induced magnetic hyperthermia. Here we show that the extent and mechanism of hyperthermia-induced cell kill is highly dependent on the aggregation state of SPIO nanoparticles. Well-dispersed nanoparticles induced apoptosis, similar to that observed with conventional hyperthermia. Sub-micron size aggregates, on the other hand, induced temperature-dependent autophagy through generation of oxidative stress. Micron size aggregates caused rapid membrane damage, resulting in acute cell kill. Overall, this work highlights the potential for developing highly effective anticancer therapeutics through designed aggregation of nano delivery systems. PMID:24947232

  18. Enhancing therapeutic efficacy through designed aggregation of nanoparticles.

    PubMed

    Sadhukha, Tanmoy; Wiedmann, Timothy S; Panyam, Jayanth

    2014-09-01

    Particle size is a key determinant of biological performance of sub-micron size delivery systems. Previous studies investigating the effect of particle size have primarily focused on well-dispersed nanoparticles. However, inorganic nanoparticles are prone to aggregation in biological environments. In our studies, we examined the consequence of aggregation on superparamagnetic iron oxide (SPIO) nanoparticle-induced magnetic hyperthermia. Here we show that the extent and mechanism of hyperthermia-induced cell kill is highly dependent on the aggregation state of SPIO nanoparticles. Well-dispersed nanoparticles induced apoptosis, similar to that observed with conventional hyperthermia. Sub-micron size aggregates, on the other hand, induced temperature-dependent autophagy through generation of oxidative stress. Micron size aggregates caused rapid membrane damage, resulting in acute cell kill. Overall, this work highlights the potential for developing highly effective anticancer therapeutics through designed aggregation of nano delivery systems.

  19. The culture of Chlorella vulgaris with human urine in multibiological life support system experiments

    NASA Astrophysics Data System (ADS)

    Li, Ming; Liu, Hong; Tong, Ling; Fu, Yuming; He, Wenting; Hu, Enzhu; Hu, Dawei

    The Integrative Experimental System (IES) was established as a tool to evaluate the rela-tionship of the subsystems in Bioregenerative Life Support System, and Multibiological Life Support System Experiments (MLSSE) have been conducted in the IES. The IES consists of a higher plant chamber, an animal chamber and a plate photo bioreactor (PPB) which cultivated lettuce (Lactuca sativa L.), silkworm (Bombyx Mori L.) and microalgae (Chlorella vulgaris), respectively. In MLSSE, four volunteers took turns breathing the system air through a tube connected with the animal chamber periodically. According to the CO2 concentration in the IES, the automotive control system of the PPB changed the light intensity regulating the photosynthesis of Chlorella vulgaris to make CO2 /O2 in the system maintain at stable levels. Chlorella vulgaris grew with human urine by carrying certain amount of alga liquid out of the bioreactor every day with synthetic urine replenished into the system, and O2 was regenerated, at the same time human urine was purified. Results showed that this IES worked stably and Chlorella vulgaris grew well; The culture of Chlorella vulgaris could be used to keep the balance of CO2 and O2 , and the change of light intensity could control the gas composition in the IES; Microalgae culture could be used in emergency in the system, the culture of Chlorella vulgaris could recover to original state in 5 days; 15.6 ml of condensation water was obtained every day by the culture of Chlorella vulgaris; The removal efficiencies of N, P in human urine could reach to 98.2% and 99.5%.

  20. Comparison of different procedures to stabilize biogas formation after process failure in a thermophilic waste digestion system: Influence of aggregate formation on process stability

    SciTech Connect

    Kleyboecker, A.; Liebrich, M.; Kasina, M.; Kraume, M.; Wittmaier, M.; Wuerdemann, H.

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer Mechanism of process recovery with calcium oxide. Black-Right-Pointing-Pointer Formation of insoluble calcium salts with long chain fatty acids and phosphate. Black-Right-Pointing-Pointer Adsorption of VFAs by the precipitates resulting in the formation of aggregates. Black-Right-Pointing-Pointer Acid uptake and phosphate release by the phosphate-accumulating organisms. Black-Right-Pointing-Pointer Microbial degradation of volatile fatty acids in the aggregates. - Abstract: Following a process failure in a full-scale biogas reactor, different counter measures were undertaken to stabilize the process of biogas formation, including the reduction of the organic loading rate, the addition of sodium hydroxide (NaOH), and the introduction of calcium oxide (CaO). Corresponding to the results of the process recovery in the full-scale digester, laboratory experiments showed that CaO was more capable of stabilizing the process than NaOH. While both additives were able to raise the pH to a neutral milieu (pH > 7.0), the formation of aggregates was observed particularly when CaO was used as the additive. Scanning electron microscopy investigations revealed calcium phosphate compounds in the core of the aggregates. Phosphate seemed to be released by phosphorus-accumulating organisms, when volatile fatty acids accumulated. The calcium, which was charged by the CaO addition, formed insoluble salts with long chain fatty acids, and caused the precipitation of calcium phosphate compounds. These aggregates were surrounded by a white layer of carbon rich organic matter, probably consisting of volatile fatty acids. Thus, during the process recovery with CaO, the decrease in the amount of accumulated acids in the liquid phase was likely enabled by (1) the formation of insoluble calcium salts with long chain fatty acids, (2) the adsorption of volatile fatty acids by the precipitates, (3) the acid uptake by phosphorus-accumulating organisms and (4

  1. Health system factors affecting communication with pediatricians: gendered work culture in primary care.

    PubMed

    Lynch, Sean

    2011-01-01

    This qualitative study examined the roles that practice setting, education level, and gender may play in social workers' communication satisfaction with pediatricians. Taking an ethnographic approach, the researcher interviewed social workers and pediatricians who worked together to provide mental health services in primary care. The results suggested that gender at the health system level may be an issue and that gendered work culture in primary care was a factor in communication. In particular, reimbursement, an aspect of the gendered work culture, was a substantial communication barrier, and the implications for Medicaid billing are discussed. PMID:22085327

  2. Enhanced Geothermal System Development of the AmeriCulture Leasehold in the Animas Valley

    SciTech Connect

    Duchane, David V; Seawright, Gary L; Sewright, Damon E; Brown, Don; Witcher, James c.; Nichols, Kenneth E.

    2001-03-02

    Working under the grant with AmeriCulture, Inc., and its team of geothermal experts, assembled a plan to apply enhanced geothermal systems (EGS) techniques to increase both the temperature and flow rate of the geothermal waters on its leasehold. AmeriCulture operates a commercial aquaculture facility that will benefit from the larger quantities of thermal energy and low cost electric power that EGS technology can provide. The project brought together a team of specialists that, as a group, provided the full range of expertise required to successfully develop and implement the project.

  3. Incubator embedded cell culture imaging system (EmSight) based on Fourier ptychographic microscopy.

    PubMed

    Kim, Jinho; Henley, Beverley M; Kim, Charlene H; Lester, Henry A; Yang, Changhuei

    2016-08-01

    Multi-day tracking of cells in culture systems can provide valuable information in bioscience experiments. We report the development of a cell culture imaging system, named EmSight, which incorporates multiple compact Fourier ptychographic microscopes with a standard multiwell imaging plate. The system is housed in an incubator and presently incorporates six microscopes. By using the same low magnification objective lenses as the objective and the tube lens, the EmSight is configured as a 1:1 imaging system that, providing large field-of-view (FOV) imaging onto a low-cost CMOS imaging sensor. The EmSight improves the image resolution by capturing a series of images of the sample at varying illumination angles; the instrument reconstructs a higher-resolution image by using the iterative Fourier ptychographic algorithm. In addition to providing high-resolution brightfield and phase imaging, the EmSight is also capable of fluorescence imaging at the native resolution of the objectives. We characterized the system using a phase Siemens star target, and show four-fold improved coherent resolution (synthetic NA of 0.42) and a depth of field of 0.2 mm. To conduct live, long-term dopaminergic neuron imaging, we cultured ventral midbrain from mice driving eGFP from the tyrosine hydroxylase promoter. The EmSight system tracks movements of dopaminergic neurons over a 21 day period. PMID:27570701

  4. Incubator embedded cell culture imaging system (EmSight) based on Fourier ptychographic microscopy

    PubMed Central

    Kim, Jinho; Henley, Beverley M.; Kim, Charlene H.; Lester, Henry A.; Yang, Changhuei

    2016-01-01

    Multi-day tracking of cells in culture systems can provide valuable information in bioscience experiments. We report the development of a cell culture imaging system, named EmSight, which incorporates multiple compact Fourier ptychographic microscopes with a standard multiwell imaging plate. The system is housed in an incubator and presently incorporates six microscopes. By using the same low magnification objective lenses as the objective and the tube lens, the EmSight is configured as a 1:1 imaging system that, providing large field-of-view (FOV) imaging onto a low-cost CMOS imaging sensor. The EmSight improves the image resolution by capturing a series of images of the sample at varying illumination angles; the instrument reconstructs a higher-resolution image by using the iterative Fourier ptychographic algorithm. In addition to providing high-resolution brightfield and phase imaging, the EmSight is also capable of fluorescence imaging at the native resolution of the objectives. We characterized the system using a phase Siemens star target, and show four-fold improved coherent resolution (synthetic NA of 0.42) and a depth of field of 0.2 mm. To conduct live, long-term dopaminergic neuron imaging, we cultured ventral midbrain from mice driving eGFP from the tyrosine hydroxylase promoter. The EmSight system tracks movements of dopaminergic neurons over a 21 day period. PMID:27570701

  5. A bladder cancer microenvironment simulation system based on a microfluidic co-culture model

    PubMed Central

    Zhao, Yang; Liu, Xiao-guang; Shi, Hao-qing; Hu, Ke-yao; Zhu, Guan-qun; Ma, Bo; Niu, Hai-tao

    2015-01-01

    A tumor microenvironment may promote tumor metastasis and progression through the dynamic interplay between neoplastic cells and stromal cells. In this work, the most representative and significant stromal cells, fibroblasts, endothelial cells, and macrophages were used as vital component elements and combined with bladder cancer cells to construct a bladder cancer microenvironment simulation system. This is the first report to explore bladder cancer microenvironments based on 4 types of cells co-cultured simultaneously. This simulation system comprises perfusion equipment, matrigel channel units, a medium channel and four indirect contact culture chambers, allowing four types of cells to simultaneously interact through soluble biological factors and metabolites. With this system, bladder cancer cells (T24) with a tendency to form a ‘reticular’ structure under 3 dimensional culture conditions were observed in real time. The microenvironment characteristics of paracrine interactions and cell motility were successfully simulated in this system. The phenotype change process in stromal cells was successfully reproduced in this system by testing the macrophage effector molecule Arg-1. Arg-1 was highly expressed in the simulated tumor microenvironment group. To develop “precision medicine” in bladder cancer therapy, bladder cancer cells were treated with different clinical ‘neo-adjuvant’ chemotherapy schemes in this system, and their sensitivity differences were fully reflected. This work provides a preliminary foundation for neo-adjuvant chemotherapy in bladder cancer, a theoretical foundation for tumor microenvironment simulation and promotes individual therapy in bladder cancer patients. PMID:26462177

  6. Use of a Closed Culture System to Improve the Safety of Lentiviral Vector Production.

    PubMed

    Wu, Tao; Bour, Gaëtan; Durand, Sarah; Lindner, Véronique; Gossé, Francine; Zona, Laetitia; Certoux, Jean-Marie; Diana, Michele; Baumert, Thomas F; Marescaux, Jacques; Mutter, Didier; Pessaux, Patrick; Robinet, Eric

    2015-12-01

    We evaluated the possibility of introducing a combination of six oncogenes into primary porcine hepatocytes (PPH) using a lentiviral vector (LV)-mediated gene transfer in order to develop a porcine hepatocellular carcinoma model based on autologous transplantation of ex vivo-transformed hepatocytes. The six oncogenes were introduced into three plasmids, hence enabling the production of LVs encoding a luciferase reporter gene and hTERT+p53(DD), cyclinD1+CDK4(R24C), and c-myc(T58A)+HRas(G21V) genes, respectively. In order to improve the protection of the laboratory personnel manipulating such LVs, we used a compact cell culture cassette (CliniCell(®) device) as a closed cell culture system. We demonstrated that the CliniCell device allows to produce LVs, through plasmid transfection of 293T cells, and, after transfer to a second cassette, to transduce PPH with a similar efficacy as conventional open cell culture systems such as flasks or Petri dishes. Additionally, it is possible to cryopreserve at -80°C the transduced cells, directly in the CliniCell device used for the transduction. In conclusion, the use of a closed culture system for the safe handling of oncogene-encoding LVs lays the foundation for the development of porcine tumor models based on the autologous transplantation of ex vivo-transformed primary cells. PMID:26467420

  7. Modelling of Microalgae Culture Systems with Applications to Control and Optimization.

    PubMed

    Bernard, Olivier; Mairet, Francis; Chachuat, Benoît

    2016-01-01

    Mathematical modeling is becoming ever more important to assess the potential, guide the design, and enable the efficient operation and control of industrial-scale microalgae culture systems (MCS). The development of overall, inherently multiphysics, models involves coupling separate submodels of (i) the intrinsic biological properties, including growth, decay, and biosynthesis as well as the effect of light and temperature on these processes, and (ii) the physical properties, such as the hydrodynamics, light attenuation, and temperature in the culture medium. When considering high-density microalgae culture, in particular, the coupling between biology and physics becomes critical. This chapter reviews existing models, with a particular focus on the Droop model, which is a precursor model, and it highlights the structure common to many microalgae growth models. It summarizes the main developments and difficulties towards multiphysics models of MCS as well as applications of these models for monitoring, control, and optimization purposes.

  8. B35 neuroblastoma cells: an easily transfected, cultured cell model of central nervous system neurons.

    PubMed

    Otey, Carol A; Boukhelifa, Malika; Maness, Patricia

    2003-01-01

    A panel of neuronal cell lines was derived from tumors of the neonatal rat central nervous system (CNS) in 1974, and two of these lines are in wide use today. Both the B35 and B50 lines offer a number of advantages to researchers who study CNS neurons in culture: they are simple to grow, to differentiate, and to transfect. B50 cells have been used extensively in the study of neuronal cell death, toxicology, and differentiation, whereas B35 cells have proven useful in the molecular analysis of endocytosis and of signaling pathways, in particular those that guide axonal outgrowth and cell motility. This chapter provides protocols for growing and transfecting B35 cells, selecting stable transfectants, exploring protein function using an antisense approach, and assaying cell motility in a Transwell chamber. All of these protocols have been written for researchers who have some skill in basic cell culture techniques, but previous experience with cultured neurons is not required.

  9. Biodegradation of haloacetic acids by bacterial isolates and enrichment cultures from drinking water systems.

    PubMed

    Zhang, Ping; Lapara, Timothy M; Goslan, Emma H; Xie, Yuefeng; Parsons, Simon A; Hozalski, Raymond M

    2009-05-01

    Biodegradation is a potentially important loss process for haloacetic acids (HAAs), a class of chlorination byproducts, in water treatment and distribution systems, but little is known about the organisms involved (i.e., identity, substrate range, biodegradation kinetics). In this research, 10 biomass samples (i.e., tap water, distribution system biofilms, and prechlorinated granular activated carbon filters) from nine drinking water systems were used to inoculate a total of thirty enrichment cultures fed monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), or trichloroacetic (TCAA) as sole carbon and energy source. HAA degraders were successfully enriched from the biofilm samples (GAC and distribution system) but rarely from tap water. Half of the MCAA and DCAA enrichment cultures were positive, whereas only one TCAA culture was positive (two were inconclusive). Eight unique HAA-degrading isolates were obtained including several Afipia spp. and a Methylobacterium sp.; all isolates were members of the phylum Proteobacteria. MCAA, monobromoacetic acid (MBAA), and monoiodoacetic acid (MIAA) were rapidly degraded by all isolates, and DCAA and tribromoacetic (TBAA) were also relatively labile. TCAA and dibromoacetic acid (DBAA)were degraded by only three isolates and degradation lagged behind the other HAAs. Detailed DCAA biodegradation kinetics were obtained for two selected isolates and two enrichment cultures. The maximum biomass-normalized degradation rates (Vm) were 0.27 and 0.97 microg DCAA/ microg protein/h for Methylobacterium fujisawaense strain PAWDI and Afipia felis strain EMD2, respectively, which were comparable to the values obtained for the enrichment cultures from which those organisms were isolated (0.39 and 1.37 microg DCAN/microg protein/h, respectively). The half-saturation constant (Km) values ranged from 4.38 to 77.91 microg DCAA/L and the cell yields ranged from 14.4 to 36.1 mg protein/g DCAA.

  10. [Identification of staphylococci directly from positive blood culture bottles by MALDI-TOF MS system].

    PubMed

    Kilic, Abdullah; Baysallar, Mehmet

    2014-07-01

    Bloodstream infections are substantial causes of morbidity and mortality worldwide. Staphylococcus species are the most commonly isolated microorganisms from blood cultures in clinical microbiology laboratories. MALDI-TOF MS (Matrix-Assisted Laser Desorption/Ionization Time- of- Flight Mass Spectrometry) system allows the identification of microorganisms directly from positive blood culture bottles. The aim of this study was to evaluate the MALDI-TOF MS system for the identification of staphylococci directly from the positive blood culture bottles which revealed the presence of gram-positive cocci by staining. A total of 96 positive blood culture bottles that yielded gram-positive cocci by Gram stain were evaluated. These blood cultures were obtained from 69 patients between December 2013-February 2014. Conventional methods and BD Phoenix™ automated bacterial identification system (Becton Dickinson, USA) were used for routine identification. The strains were also identified by real-time Taqman PCR (qPCR) which was considered as the reference method. In MALDI-TOF MS method, MALDI Sepsityper™ Kit was used for the bacterial identification and all measurements were carried out by using Microflex LT instrument and FlexControl 3.0 software (Bruker Daltonics, USA). Of 96 culture bottles positive for gram-positive cocci, 90 were correctly identified as staphylococci at genus level with all the three study methods (qPCR, BD Phoenix, Bruker MALDI-TOF MS). The other six samples were identified as Enterococcus faecium (n= 4) and Streptococcus pyogenes (n= 2) by both Phoenix and the MALDI-TOF systems. Of the 90 samples, 87 were identified at the species level (15 S.aureus, 33 S.epidermidis, 29 S.hominis, 10 S.haemolyticus) and three at the genus level by the reference qPCR method. When comparing the results obtained by qPCR and Bruker MALDI-TOF MS, incompatibility was detected for three isolates. Those isolates were identified as S.hominis by qPCR, however two of them were

  11. [Identification of staphylococci directly from positive blood culture bottles by MALDI-TOF MS system].

    PubMed

    Kilic, Abdullah; Baysallar, Mehmet

    2014-07-01

    Bloodstream infections are substantial causes of morbidity and mortality worldwide. Staphylococcus species are the most commonly isolated microorganisms from blood cultures in clinical microbiology laboratories. MALDI-TOF MS (Matrix-Assisted Laser Desorption/Ionization Time- of- Flight Mass Spectrometry) system allows the identification of microorganisms directly from positive blood culture bottles. The aim of this study was to evaluate the MALDI-TOF MS system for the identification of staphylococci directly from the positive blood culture bottles which revealed the presence of gram-positive cocci by staining. A total of 96 positive blood culture bottles that yielded gram-positive cocci by Gram stain were evaluated. These blood cultures were obtained from 69 patients between December 2013-February 2014. Conventional methods and BD Phoenix™ automated bacterial identification system (Becton Dickinson, USA) were used for routine identification. The strains were also identified by real-time Taqman PCR (qPCR) which was considered as the reference method. In MALDI-TOF MS method, MALDI Sepsityper™ Kit was used for the bacterial identification and all measurements were carried out by using Microflex LT instrument and FlexControl 3.0 software (Bruker Daltonics, USA). Of 96 culture bottles positive for gram-positive cocci, 90 were correctly identified as staphylococci at genus level with all the three study methods (qPCR, BD Phoenix, Bruker MALDI-TOF MS). The other six samples were identified as Enterococcus faecium (n= 4) and Streptococcus pyogenes (n= 2) by both Phoenix and the MALDI-TOF systems. Of the 90 samples, 87 were identified at the species level (15 S.aureus, 33 S.epidermidis, 29 S.hominis, 10 S.haemolyticus) and three at the genus level by the reference qPCR method. When comparing the results obtained by qPCR and Bruker MALDI-TOF MS, incompatibility was detected for three isolates. Those isolates were identified as S.hominis by qPCR, however two of them were

  12. Plasma-mediated inactivation of Pseudomonas aeruginosa biofilms grown on borosilicate surfaces under continuous culture system.

    PubMed

    Vandervoort, Kurt G; Brelles-Mariño, Graciela

    2014-01-01

    Biofilms are microbial communities attached to a surface and embedded in a matrix composed of exopolysaccharides and excreted nucleic acids. Bacterial biofilms are responsible for undesirable effects such as disease, prostheses colonization, biofouling, equipment damage, and pipe plugging. Biofilms are also more resilient than free-living cells to regular sterilization methods and therefore it is indispensable to develop better ways to control and remove them. The use of gas discharge plasmas is a good alternative since plasmas contain a mixture of reactive agents well-known for their decontamination potential against free microorganisms. We have previously reported that Pseudomonas aeruginosa biofilms were inactivated after a 1-min plasma exposure. We determined that the adhesiveness and the thickness of Pseudomonas biofilms grown on borosilicate were reduced. We also reported sequential morphological changes and loss of viability upon plasma treatment. However, the studies were carried out in batch cultures. The use of a continuous culture results in a more homogenous environment ensuring reproducible biofilm growth. The aim of this work was to study plasma-mediated inactivation of P. aeruginosa biofilms grown on borosilicate in a continuous culture system. In this paper we show that biofilms grown on glass under continuous culture can be inactivated by using gas discharge plasma. Both biofilm architecture and cell culturability are impacted by the plasma treatment. The inactivation kinetics is similar to previously described ones and cells go through sequential changes ranging from minimal modification without loss of viability at short plasma exposure times, to major structure and viability loss at longer exposure times. We report that changes in biofilm structure leading to the loss of culturability and viability are related to a decrease of the biofilm matrix adhesiveness. To our knowledge, there has been no attempt to evaluate the inactivation

  13. Assessment of patient safety culture in clinical laboratories in the Spanish National Health System

    PubMed Central

    Giménez-Marín, Angeles; Rivas-Ruiz, Francisco; García-Raja, Ana M.; Venta-Obaya, Rafael; Fusté-Ventosa, Margarita; Caballé-Martín, Inmaculada; Benítez-Estevez, Alfonso; Quinteiro-García, Ana I.; Bedini, José Luis; León-Justel, Antonio; Torra-Puig, Montserrat

    2015-01-01

    Introduction There is increasing awareness of the importance of transforming organisational culture in order to raise safety standards. This paper describes the results obtained from an evaluation of patient safety culture in a sample of clinical laboratories in public hospitals in the Spanish National Health System. Material and methods A descriptive cross-sectional study was conducted among health workers employed in the clinical laboratories of 27 public hospitals in 2012. The participants were recruited by the heads of service at each of the participating centers. Stratified analyses were performed to assess the mean score, standardized to a base of 100, of the six survey factors, together with the overall patient safety score. Results 740 completed questionnaires were received (88% of the 840 issued). The highest standardized scores were obtained in Area 1 (individual, social and cultural) with a mean value of 77 (95%CI: 76-78), and the lowest ones, in Area 3 (equipment and resources), with a mean value of 58 (95%CI: 57-59). In all areas, a greater perception of patient safety was reported by the heads of service than by other staff. Conclusions We present the first multicentre study to evaluate the culture of clinical safety in public hospital laboratories in Spain. The results obtained evidence a culture in which high regard is paid to safety, probably due to the pattern of continuous quality improvement. Nevertheless, much remains to be done, as reflected by the weaknesses detected, which identify areas and strategies for improvement. PMID:26525595

  14. Gut bacteria mediate aggregation in the German cockroach

    PubMed Central

    Wada-Katsumata, Ayako; Zurek, Ludek; Nalyanya, Godfrey; Roelofs, Wendell L.; Zhang, Aijun; Schal, Coby

    2015-01-01

    Aggregation of the German cockroach, Blattella germanica, is regulated by fecal aggregation agents (pheromones), including volatile carboxylic acids (VCAs). We demonstrate that the gut microbial community contributes to production of these semiochemicals. Chemical analysis of the fecal extract of B. germanica revealed 40 VCAs. Feces from axenic cockroaches (no microorganisms in the alimentary tract) lacked 12 major fecal VCAs, and 24 of the remaining compounds were represented at extremely low amounts. Olfactory and aggregation bioassays demonstrated that nymphs strongly preferred the extract of control feces over the fecal extract of axenic cockroaches. Additionally, nymphs preferred a synthetic blend of 6 fecal VCAs over a solvent control or a previously identified VCA blend. To test whether gut bacteria contribute to the production of fecal aggregation agents, fecal aerobic bacteria were cultured, isolated, and identified. Inoculation of axenic cockroaches with individual bacterial taxa significantly rescued the aggregation response to the fecal extract, and inoculation with a mix of six bacterial isolates was more effective than with single isolates. The results indicate that the commensal gut microbiota contributes to production of VCAs that act as fecal aggregation agents and that cockroaches discriminate among the complex odors that emanate from a diverse microbial community. Our results highlight the pivotal role of gut bacteria in mediating insect–insect communication. Moreover, because the gut microbial community reflects the local environment, local plasticity in fecal aggregation pheromones enables colony-specific odors and fidelity to persistent aggregation sites. PMID:26644557

  15. 3d Modeling of cultural heritage objects with a structured light system.

    NASA Astrophysics Data System (ADS)

    Akca, Devrim

    3D modeling of cultural heritage objects is an expanding application area. The selection of the right technology is very important and strictly related to the project requirements, budget and user's experience. The triangulation based active sensors, e.g. structured light systems are used for many kinds of 3D object reconstruction tasks and in particular for 3D recording of cultural heritage objects. This study presents the experiences in the results of two such projects in which a close-range structured light system is used for the 3D digitization. The paper includes the essential steps of the 3D object modeling pipeline, i.e. digitization, registration, surface triangulation, editing, texture mapping and visualization. The capabilities of the used hardware and software are addressed. Particular emphasis is given to a coded structured light system as an option for data acquisition.

  16. Response of sago pondweed, a submerged aquatic macrophyte, to herbicides in three laboratory culture systems

    USGS Publications Warehouse

    Fleming, W.J.; Ailstock, M.S.; Momot, J.J.; Norman, C.M.; Gorsuch, Joseph W.; Lower, William R.; Wang, Wun-cheng; Lewis, M.A.

    1991-01-01

    The phytotoxicity of atrazine, paraquat, glyphosate, and alachlor to sago pondweed (Potamogeton pectinatus), a submerged aquatic macrophyte, was tested under three types of laboratory culture conditions. In each case, tests were conducted in static systems, the test period was four weeks, and herbicide exposure was chronic, resulting from a single addition of herbicide to the test vessels at the beginning of the test period. The three sets of test conditions employed were(1) axenic cultures in 125-mL flasks containing a nutrient media and sucrose; (2) a microcosm system employing 18.9-L buckets containing a sand, shell, and peat substrate; and (3) an algae-free system employing O.95-L jars containing reconstituted freshwater and a nutrient agar substrate. The primary variable measured was biomass production. Plants grew well in all three test systems, with biomass of untreated plants increasing by a factor of about 5 to 6.5 during the four-week test period. Biomass production in response to herbicide exposure differed significantly among culture systems, which demonstrates the need for a standardized testing protocol for evaluating the effects of toxics on submerged aquatic plants.

  17. Detergent-mediated protein aggregation.

    PubMed

    Neale, Chris; Ghanei, Hamed; Holyoake, John; Bishop, Russell E; Privé, Gilbert G; Pomès, Régis

    2013-04-01

    Because detergents are commonly used to solvate membrane proteins for structural evaluation, much attention has been devoted to assessing the conformational bias imparted by detergent micelles in comparison to the native environment of the lipid bilayer. Here, we conduct six 500-ns simulations of a system with >600,000 atoms to investigate the spontaneous self assembly of dodecylphosphocholine detergent around multiple molecules of the integral membrane protein PagP. This detergent formed equatorial micelles in which acyl chains surround the protein's hydrophobic belt, confirming existing models of the detergent solvation of membrane proteins. In addition, unexpectedly, the extracellular and periplasmic apical surfaces of PagP interacted with the headgroups of detergents in other micelles 85 and 60% of the time, respectively, forming complexes that were stable for hundreds of nanoseconds. In some cases, an apical surface of one molecule of PagP interacted with an equatorial micelle surrounding another molecule of PagP. In other cases, the apical surfaces of two molecules of PagP simultaneously bound a neat detergent micelle. In these ways, detergents mediated the non-specific aggregation of folded PagP. These simulation results are consistent with dynamic light scattering experiments, which show that, at detergent concentrations ≥600 mM, PagP induces the formation of large scattering species that are likely to contain many copies of the PagP protein. Together, these simulation and experimental results point to a potentially generic mechanism of detergent-mediated protein aggregation.

  18. Cellular Strategies for Regulating Functional and Nonfunctional Protein Aggregation

    PubMed Central

    Gsponer, Jörg; Babu, M. Madan

    2012-01-01

    Summary Growing evidence suggests that aggregation-prone proteins are both harmful and functional for a cell. How do cellular systems balance the detrimental and beneficial effect of protein aggregation? We reveal that aggregation-prone proteins are subject to differential transcriptional, translational, and degradation control compared to nonaggregation-prone proteins, which leads to their decreased synthesis, low abundance, and high turnover. Genetic modulators that enhance the aggregation phenotype are enriched in genes that influence expression homeostasis. Moreover, genes encoding aggregation-prone proteins are more likely to be harmful when overexpressed. The trends are evolutionarily conserved and suggest a strategy whereby cellular mechanisms specifically modulate the availability of aggregation-prone proteins to (1) keep concentrations below the critical ones required for aggregation and (2) shift the equilibrium between the monomeric and oligomeric/aggregate form, as explained by Le Chatelier’s principle. This strategy may prevent formation of undesirable aggregates and keep functional assemblies/aggregates under control. PMID:23168257

  19. Effect of Culture System on Developmental Competence, Cryosurvival and DNA-Fragmentation of In Vitro Bovine Blastocysts

    PubMed Central

    Hajian, Mahdi; Hosseini, Seyed Morteza; Asgari, Vajiheh; Ostadhoosseini, Somayyeh; Forouzanfar, Mohsen; Nasr Esfahani, Mohammad Hossein

    2011-01-01

    Background This study investigated the effect of two in vitro embryo culture systems (co-culture system versus cell-free sequential-media) on developmental competence, cryosurvival and DNA- fragmentation of in vitro developed bovine blastocysts. Materials and Methods Bovine presumptive zygotes were cultured in Ménézo's B2 (B2) plus vero-cells or sequential synthetic oviductal fluid (SOF) for eight days. Subsequently, half of the expanded blastocysts developed in both groups were vitrified, warmed within 30 minutes and post- warming embryos along with their corresponding non-vitrified embryos were cultured for two additional days in the same medium used before vitrification. Embryo development, cryosurvival and apoptosis were compared between the groups. Results For non-vitrified embryos, culture in SOF significantly promoted the potency of embryos to develop into blastocysts compared with the co-culture system. The difference in post vitrification survival rate of SOF blastocysts (83.3%) was insignificant compared with co-culture (84.3%). However, while total cell number of warmed blastocysts in the co-culture system was significantly higher in the co-culture versus the sequential system (215.4 vs. 170.4), the quality of survived embryos in terms of hatching ability and apoptosis was adversely affected by co-culture compared with SOF (65.0% vs. 74.3%, and 13.5% vs. 10.0%, respectively; p<0.05). Conclusion Although co-culture system may increase the viability of embryos following cryopreservation, the potency and dynamics of blastocyst formation significantly increased with sequential media compared to the co-culture system which can compensate for the lower efficiency of sequential media for vitrification/warming purposes. PMID:24917920

  20. The Impact of Corporate Culture, the Reward System, and Perceived Moral Intensity on Marketing Students' Ethical Decision Making

    ERIC Educational Resources Information Center

    Nill, Alexander; Schibrowsky, John A.

    2005-01-01

    An experiment was conducted to study how marketing students' ethical decision making was influenced by their perceived moral intensity (PMI), corporate culture, and the reward system. The findings indicate that levels of awareness of the ethical consequences of a decision, the corporate culture, and the reward system all significantly affect…