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Sample records for cellular parameters final

  1. Estimating cellular parameters through optimization procedures: elementary principles and applications

    PubMed Central

    Kimura, Akatsuki; Celani, Antonio; Nagao, Hiromichi; Stasevich, Timothy; Nakamura, Kazuyuki

    2015-01-01

    Construction of quantitative models is a primary goal of quantitative biology, which aims to understand cellular and organismal phenomena in a quantitative manner. In this article, we introduce optimization procedures to search for parameters in a quantitative model that can reproduce experimental data. The aim of optimization is to minimize the sum of squared errors (SSE) in a prediction or to maximize likelihood. A (local) maximum of likelihood or (local) minimum of the SSE can efficiently be identified using gradient approaches. Addition of a stochastic process enables us to identify the global maximum/minimum without becoming trapped in local maxima/minima. Sampling approaches take advantage of increasing computational power to test numerous sets of parameters in order to determine the optimum set. By combining Bayesian inference with gradient or sampling approaches, we can estimate both the optimum parameters and the form of the likelihood function related to the parameters. Finally, we introduce four examples of research that utilize parameter optimization to obtain biological insights from quantified data: transcriptional regulation, bacterial chemotaxis, morphogenesis, and cell cycle regulation. With practical knowledge of parameter optimization, cell and developmental biologists can develop realistic models that reproduce their observations and thus, obtain mechanistic insights into phenomena of interest. PMID:25784880

  2. Estimating cellular parameters through optimization procedures: elementary principles and applications.

    PubMed

    Kimura, Akatsuki; Celani, Antonio; Nagao, Hiromichi; Stasevich, Timothy; Nakamura, Kazuyuki

    2015-01-01

    Construction of quantitative models is a primary goal of quantitative biology, which aims to understand cellular and organismal phenomena in a quantitative manner. In this article, we introduce optimization procedures to search for parameters in a quantitative model that can reproduce experimental data. The aim of optimization is to minimize the sum of squared errors (SSE) in a prediction or to maximize likelihood. A (local) maximum of likelihood or (local) minimum of the SSE can efficiently be identified using gradient approaches. Addition of a stochastic process enables us to identify the global maximum/minimum without becoming trapped in local maxima/minima. Sampling approaches take advantage of increasing computational power to test numerous sets of parameters in order to determine the optimum set. By combining Bayesian inference with gradient or sampling approaches, we can estimate both the optimum parameters and the form of the likelihood function related to the parameters. Finally, we introduce four examples of research that utilize parameter optimization to obtain biological insights from quantified data: transcriptional regulation, bacterial chemotaxis, morphogenesis, and cell cycle regulation. With practical knowledge of parameter optimization, cell and developmental biologists can develop realistic models that reproduce their observations and thus, obtain mechanistic insights into phenomena of interest.

  3. Ito equations out of domino cellular automaton with efficiency parameters

    NASA Astrophysics Data System (ADS)

    Czechowski, Zbigniew; Białecki, Mariusz

    2012-06-01

    Ito equations are derived for simple stochastic cellular automaton with parameters describing efficiencies for avalanche triggering and cell occupation. Analytical results are compared with the numerical one obtained from the histogram method. Good agreement for various parameters supports the wide applicability of the Ito equation as a macroscopic model of some cellular automata and complex natural phenomena which manifest random energy release. Also, the paper is an example of effectiveness of histogram procedure as an adequate method of nonlinear modeling of time series.

  4. Effect of hyperthermic water bath on parameters of cellular immunity.

    PubMed

    Blazícková, S; Rovenský, J; Koska, J; Vigas, M

    2000-01-01

    Effects of hyperthermic water bath on selected immune parameters (lymphocyte subpopulations, natural killer (NK) cell counts and their activity) were studied in a group of 10 volunteers. Application of hyperthermic water bath (both topical and whole-body) was followed by a significant reduction of relative B lymphocyte counts. Whole-body hyperthermic water bath reduced relative total T lymphocyte counts, increased relative CD8+ T lymphocyte and NK cell counts and increased NK activity. Whole-body hyperthermic bath increased somatotropic hormone (STH) activity in eight out of 10 volunteers; higher relative counts of CD8+ lymphocytes and NK cells were observed compared with the group of volunteers not responding to hyperthermic water bath by STH secretion. In five volunteers STH was released in response to local hyperthermic water bath and the NK activity of lymphocytes also increased but their relative counts did not. The results suggest that these increases in CD8+ lymphocyte and NK cell counts are probably dependent on increased STH production.

  5. Parameters and characteristics governing cellular internalization and trans-barrier trafficking of nanostructures

    PubMed Central

    Murugan, Karmani; Choonara, Yahya E; Kumar, Pradeep; Bijukumar, Divya; du Toit, Lisa C; Pillay, Viness

    2015-01-01

    Cellular internalization and trans-barrier transport of nanoparticles can be manipulated on the basis of the physicochemical and mechanical characteristics of nanoparticles. Research has shown that these factors significantly influence the uptake of nanoparticles. Dictating these characteristics allows for the control of the rate and extent of cellular uptake, as well as delivering the drug-loaded nanosystem intra-cellularly, which is imperative for drugs that require a specific cellular level to exert their effects. Additionally, physicochemical characteristics of the nanoparticles should be optimal for the nanosystem to bypass the natural restricting phenomena of the body and act therapeutically at the targeted site. The factors at the focal point of emerging smart nanomedicines include nanoparticle size, surface charge, shape, hydrophobicity, surface chemistry, and even protein and ligand conjugates. Hence, this review discusses the mechanism of internalization of nanoparticles and ideal nanoparticle characteristics that allow them to evade the biological barriers in order to achieve optimal cellular uptake in different organ systems. Identifying these parameters assists with the progression of nanomedicine as an outstanding vector of pharmaceuticals. PMID:25834433

  6. [The influence of solcoseryl on population and cellular parameters of HeLa and RD cultures].

    PubMed

    Magakian, Iu A; Karalian, Z A; Karalova, E M; Abroian, L O; Akopian, L A; Gasparian, M G; Dzhagatspanian, N G; Semerdzhian, Z B; Ter-Pogosian, Z R

    2010-01-01

    Changes of population and cellular parameters of HeLa and RD cultures after introducing of solcoseryl in culture medium were studied by methods of scanning cytophotometry and cytomorphometry. Monolayer density, proliferation activity, the number of dead cells in a monolayer, the number of nucleoli in nuclei and distribution of cells in the populations by this parameter, RNA and DNA masses in nuclei and nucleoli, total volumes and surface areas of the nuclei and nucleoli were determined. It has been shown that solcoseryl differently affects the cultures both on population and on cellular levels of their organization. The results of multi-parametric analysis of the influence of solseryl on the cultures allow considering it as a biologically active compound with the features typical for cell and cell population growth regulating factors.

  7. Estimating genetic and phenotypic parameters of cellular immune-associated traits in dairy cows.

    PubMed

    Denholm, Scott J; McNeilly, Tom N; Banos, Georgios; Coffey, Mike P; Russell, George C; Bagnall, Ainsley; Mitchell, Mairi C; Wall, Eileen

    2017-04-01

    Data collected from an experimental Holstein-Friesian research herd were used to determine genetic and phenotypic parameters of innate and adaptive cellular immune-associated traits. Relationships between immune-associated traits and production, health, and fertility traits were also investigated. Repeated blood leukocyte records were analyzed in 546 cows for 9 cellular immune-associated traits, including percent T cell subsets, B cells, NK cells, and granulocytes. Variance components were estimated by univariate analysis. Heritability estimates were obtained for all 9 traits, the highest of which were observed in the T cell subsets percent CD4(+), percent CD8(+), CD4(+):CD8(+) ratio, and percent NKp46(+) cells (0.46, 0.41, 0.43 and 0.42, respectively), with between-individual variation accounting for 59 to 81% of total phenotypic variance. Associations between immune-associated traits and production, health, and fertility traits were investigated with bivariate analyses. Strong genetic correlations were observed between percent NKp46(+) and stillbirth rate (0.61), and lameness episodes and percent CD8(+) (-0.51). Regarding production traits, the strongest relationships were between CD4(+):CD8(+) ratio and weight phenotypes (-0.52 for live weight; -0.51 for empty body weight). Associations between feed conversion traits and immune-associated traits were also observed. Our results provide evidence that cellular immune-associated traits are heritable and repeatable, and the noticeable variation between animals would permit selection for altered trait values, particularly in the case of the T cell subsets. The associations we observed between immune-associated, health, fertility, and production traits suggest that genetic selection for cellular immune-associated traits could provide a useful tool in improving animal health, fitness, and fertility.

  8. Tetrazolium-based assays for cellular viability: a critical examination of selected parameters affecting formazan production.

    PubMed

    Vistica, D T; Skehan, P; Scudiero, D; Monks, A; Pittman, A; Boyd, M R

    1991-05-15

    The hydrogen acceptor 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) is commonly utilized to estimate cellular viability in drug screening protocols. The present investigation was prompted, in part, by observations that reduction of MTT to its colored reaction product, MTT formazan, varied between cell lines and with culture age. A correlation was established between the D-glucose concentration of the culture medium at the time of assay and the production of MTT formazan for cell lines representing seven tumor histologies. A decrease in the concentration of D-glucose from culture medium was accompanied by a decrease in MTT specific activity (MTT formazan/microgram cell protein) for a number of cell lines. Cells which extensively metabolized D-glucose exhibited the greatest reduction in MTT specific activity. Further evidence that the D-glucose concentration of the culture medium played an important role in MTT reduction was provided by experiments which demonstrated that transfer of cells to a glucose-free medium (L-15) was accompanied by an immediate decrease in MTT reduction which was pH independent. These studies suggested that cellular transport and constant metabolism of glucose were required for maximum MTT reduction. Decreases in the cellular concentration of the reduced pyridine nucleotides NADH and NADPH were accompanied by concomitant decreases in MTT formazan production. MTT formazan varied significantly among cell lines in both the kinetics of its formation and the degree of saturability exhibited. Apparent IC50 values for Adriamycin varied, in a cell line-specific manner, with MTT exposure time. These results indicate that MTT specific activity is significantly influenced by a number of parameters and suggest that assay conditions should be established which minimize their effects.

  9. Engineering parameters for environmental remediation technologies. Final report

    SciTech Connect

    Kikkeri, S.R.

    1996-06-01

    This document identifies engineering parameters and establishes ranges of values for 33 environmental remediation technologies. The main purpose is to provide U.S. Coast Guard (USCG) civil engineering personnel with summarized information regarding matrix characteristics and design parameters that are applicable to each of the technologies. This information is intended to guide USCG personnel when making decisions regarding the selection of appropriate remediation technologies. This document has been developed to be used as a companion document to the Remediation Technologies Screening Matrix and Reference Guide (EPN542/B-94/013).

  10. Simultaneous model discrimination and parameter estimation in dynamic models of cellular systems

    PubMed Central

    2013-01-01

    Background Model development is a key task in systems biology, which typically starts from an initial model candidate and, involving an iterative cycle of hypotheses-driven model modifications, leads to new experimentation and subsequent model identification steps. The final product of this cycle is a satisfactory refined model of the biological phenomena under study. During such iterative model development, researchers frequently propose a set of model candidates from which the best alternative must be selected. Here we consider this problem of model selection and formulate it as a simultaneous model selection and parameter identification problem. More precisely, we consider a general mixed-integer nonlinear programming (MINLP) formulation for model selection and identification, with emphasis on dynamic models consisting of sets of either ODEs (ordinary differential equations) or DAEs (differential algebraic equations). Results We solved the MINLP formulation for model selection and identification using an algorithm based on Scatter Search (SS). We illustrate the capabilities and efficiency of the proposed strategy with a case study considering the KdpD/KdpE system regulating potassium homeostasis in Escherichia coli. The proposed approach resulted in a final model that presents a better fit to the in silico generated experimental data. Conclusions The presented MINLP-based optimization approach for nested-model selection and identification is a powerful methodology for model development in systems biology. This strategy can be used to perform model selection and parameter estimation in one single step, thus greatly reducing the number of experiments and computations of traditional modeling approaches. PMID:23938131

  11. Cellular parameters for track structure modelling of radiation hazard in space

    NASA Astrophysics Data System (ADS)

    Hollmark, M.; Lind, B.; Gudowska, I.; Waligorski, M.

    Based on irradiation with 45 MeV/u N and B ions and with Co-60 gamma rays, track structure cellular parameters have been fitted for V 79-379A Chinese hamster lung fibroblasts and for human melanoma cells (AA wtp53). These sets of parameters will be used to develop a calculation of radiation hazard in deep space, based on the system for evaluating, summing and reporting occupational exposures proposed in 1967 by subcommittee of the NCRP, but never issued as an NCRP report. The key concepts of this system were: i) expression of the risk from all radiation exposures relative to that from a whole-body exposure to Co-60 radiation; ii) relating the risk from any exposure to that of the standard (Co-60) radiation through an "effectiveness factor" (ef), a product of sub-factors representing radiation quality, body region irradiated, and depth of penetration of radiation; the product of absorbed dose by ef being termed the "exposure record unit" (eru); iii) development of ef values and a cumulative eru record for external and internal emitters. Application of this concept should provide a better description of the Gy -equivalent presently in use by NASA for evaluating risk in deep space than the equivalent dose, following ICRP-60 recommendations. Dose and charged particle fluence levels encountered in space, particularly after Solar Particle Events, require that deterministic rather than stochastic effects be considered. Also, synergistic effects due to simultaneous multiple charged particle transfers, may have to be considered. Thus, models applicable in radiotherapy, where the Gy -equivalent is also applied, in conjunction with transport calculations performed using, e.g. the ADAM and EVA phantoms, along the concepts of the 1967 NCRP system, may be more appropriate for evaluating the radiation hazard from external fields with a large flux and a major high-LET component.

  12. Parameter estimation with a novel gradient-based optimization method for biological lattice-gas cellular automaton models.

    PubMed

    Mente, Carsten; Prade, Ina; Brusch, Lutz; Breier, Georg; Deutsch, Andreas

    2011-07-01

    Lattice-gas cellular automata (LGCAs) can serve as stochastic mathematical models for collective behavior (e.g. pattern formation) emerging in populations of interacting cells. In this paper, a two-phase optimization algorithm for global parameter estimation in LGCA models is presented. In the first phase, local minima are identified through gradient-based optimization. Algorithmic differentiation is adopted to calculate the necessary gradient information. In the second phase, for global optimization of the parameter set, a multi-level single-linkage method is used. As an example, the parameter estimation algorithm is applied to a LGCA model for early in vitro angiogenic pattern formation.

  13. 2012 Gordon Research Conference on Cellular and Molecular Fungal Biology, Final Progress Report

    SciTech Connect

    Berman, Judith

    2012-06-22

    The Gordon Research Conference on Cellular and Molecular Fungal Biology was held at Holderness School, Holderness New Hampshire, June 17 - 22, 2012. The 2012 Gordon Conference on Cellular and Molecular Fungal Biology (CMFB) will present the latest, cutting-edge research on the exciting and growing field of molecular and cellular aspects of fungal biology. Topics will range from yeast to filamentous fungi, from model systems to economically important organisms, and from saprophytes and commensals to pathogens of plants and animals. The CMFB conference will feature a wide range of topics including systems biology, cell biology and morphogenesis, organismal interactions, genome organisation and regulation, pathogenesis, energy metabolism, biomass production and population genomics. The Conference was well-attended with 136 participants. Gordon Research Conferences does not permit publication of meeting proceedings.

  14. On a three-parameter quantum battle of the sexes cellular automaton

    NASA Astrophysics Data System (ADS)

    Alonso-Sanz, Ramón

    2013-05-01

    The dynamics of a spatial quantum formulation of the iterated battle of the sexes game is studied in this work. The game is played in the cellular automata manner, i.e., with local and synchronous interaction. The effect of spatial structure is assessed when allowing the players to adopt quantum strategies that are no restricted to any particular subset of the possible strategies.

  15. Advanced Cellular and Biomolecular Imaging at Lehigh University, (PA) Final Scientific/Technical Report

    SciTech Connect

    Cassimeris, Lynne, U.

    2010-09-10

    Lehigh University is establishing an interdisciplinary program in high resolution cellular and subcellular biological imaging for a range of applications including improved cancer detection. The completed DOE project added to Lehigh?s bio-imaging infrastructure through acquisition of a new confocal microscope system as well as upgrades to two pieces of existing equipment. Bio-imaging related research at Lehigh was also supported through two seed grants for initiation of new projects.

  16. Biological (molecular and cellular) markers of toxicity. Final report, September 15, 1988 - September 14, 1991

    SciTech Connect

    Shugart, L. R.; D'Surney, S. J.; Gettys-Hull, C.; Greeley, Jr, M. S.

    1991-12-15

    Several molecular and cellular markers of genotoxicity were adapted for measurement in the Medaka (Oryzias latipes), and were used to describe the effects of treatment of the organism with diethylnitrosamine (DEN). NO{sup 6}-ethyl guanine adducts were detected, and a slight statistically significant, increase in DNA strand breaks was observed. These results are consistent with the hypothesis that prolonged exposure to high levels of DEN induced alkyltransferase activity which enzymatically removes any O{sup 6}-ethyl guanine adducts but does not result in strand breaks or hypomethylation of the DNA such as might be expected from excision repair of chemically modified DNA. Following a five week continuous DEN exposure with 100 percent renewal of DEN-water every third day, the F values (DNA double strandedness) increased considerably and to similar extent in fish exposed to 25, 50, and 100 ppM DEN. This has been observed also in medaka exposed to BaP.

  17. Number of Nanoparticles per Cell through a Spectrophotometric Method - A key parameter to Assess Nanoparticle-based Cellular Assays

    PubMed Central

    Unciti-Broceta, Juan D.; Cano-Cortés, Victoria; Altea-Manzano, Patricia; Pernagallo, Salvatore; Díaz-Mochón, Juan J.; Sánchez-Martín, Rosario M.

    2015-01-01

    Engineered nanoparticles (eNPs) for biological and biomedical applications are produced from functionalised nanoparticles (NPs) after undergoing multiple handling steps, giving rise to an inevitable loss of NPs. Herein we present a practical method to quantify nanoparticles (NPs) number per volume in an aqueous suspension using standard spectrophotometers and minute amounts of the suspensions (up to 1 μL). This method allows, for the first time, to analyse cellular uptake by reporting NPs number added per cell, as opposed to current methods which are related to solid content (w/V) of NPs. In analogy to the parameter used in viral infective assays (multiplicity of infection), we propose to name this novel parameter as multiplicity of nanofection. PMID:25976173

  18. Number of Nanoparticles per Cell through a Spectrophotometric Method - A key parameter to Assess Nanoparticle-based Cellular Assays.

    PubMed

    Unciti-Broceta, Juan D; Cano-Cortés, Victoria; Altea-Manzano, Patricia; Pernagallo, Salvatore; Díaz-Mochón, Juan J; Sánchez-Martín, Rosario M

    2015-05-15

    Engineered nanoparticles (eNPs) for biological and biomedical applications are produced from functionalised nanoparticles (NPs) after undergoing multiple handling steps, giving rise to an inevitable loss of NPs. Herein we present a practical method to quantify nanoparticles (NPs) number per volume in an aqueous suspension using standard spectrophotometers and minute amounts of the suspensions (up to 1 μL). This method allows, for the first time, to analyse cellular uptake by reporting NPs number added per cell, as opposed to current methods which are related to solid content (w/V) of NPs. In analogy to the parameter used in viral infective assays (multiplicity of infection), we propose to name this novel parameter as multiplicity of nanofection.

  19. Effects of 60-day bed rest with and without exercise on cellular and humoral immunological parameters.

    PubMed

    Hoff, Paula; Belavý, Daniel L; Huscher, Dörte; Lang, Annemarie; Hahne, Martin; Kuhlmey, Anne-Kathrin; Maschmeyer, Patrick; Armbrecht, Gabriele; Fitzner, Rudolf; Perschel, Frank H; Gaber, Timo; Burmester, Gerd-Rüdiger; Straub, Rainer H; Felsenberg, Dieter; Buttgereit, Frank

    2015-07-01

    Exercise at regular intervals is assumed to have a positive effect on immune functions. Conversely, after spaceflight and under simulated weightlessness (e.g., bed rest), immune functions can be suppressed. We aimed to assess the effects of simulated weightlessness (Second Berlin BedRest Study; BBR2-2) on immunological parameters and to investigate the effect of exercise (resistive exercise with and without vibration) on these changes. Twenty-four physically and mentally healthy male volunteers (20-45 years) performed resistive vibration exercise (n=7), resistance exercise without vibration (n=8) or no exercise (n=9) within 60 days of bed rest. Blood samples were taken 2 days before bed rest, on days 19 and 60 of bed rest. Composition of immune cells was analyzed by flow cytometry. Cytokines and neuroendocrine parameters were analyzed by Luminex technology and ELISA/RIA in plasma. General changes over time were identified by paired t-test, and exercise-dependent effects by pairwise repeated measurements (analysis of variance (ANOVA)). With all subjects pooled, the number of granulocytes, natural killer T cells, hematopoietic stem cells and CD45RA and CD25 co-expressing T cells increased and the number of monocytes decreased significantly during the study; the concentration of eotaxin decreased significantly. Different impacts of exercise were seen for lymphocytes, B cells, especially the IgD(+) subpopulation of B cells and the concentrations of IP-10, RANTES and DHEA-S. We conclude that prolonged bed rest significantly impacts immune cell populations and cytokine concentrations. Exercise was able to specifically influence different immunological parameters. In summary, our data fit the hypothesis of immunoprotection by exercise and may point toward even superior effects by resistive vibration exercise.

  20. Experimental study on detonation parameters and cellular structures of fuel cloud

    NASA Astrophysics Data System (ADS)

    Xie, Li-Feng; Li, Bin; Zhang, Yu-Lei

    2012-04-01

    In this paper, detonation parameters of fuel cloud, such as propylene oxide (PO), isopropyl nitrate (IPN), hexane, 90# oil and decane were measured in a self-designed and constructed vertical shock tube. Results show that the detonation pressure and velocity of PO increase to a peak value and then decrease smoothly with increasing equivalence ratio. Several nitrate sensitizers were added into PO to make fuel mixtures, and test results indicated that the additives can efficiently enhance detonation velocity and pressure of fuel cloud and one type of additive n-propyl nitrate (NPN) played the best in the improvement. The critical initiation energy that directly initiated detonation of all the test liquid fuel clouds showed a U-shape curve relationship with equivalence ratios. The optimum concentration lies on the rich-fuel side ( ϕ > 1). The critical initiation energy is closely related to molecular structure and volatility of fuels. IPN and PO have similar critical values while that of alkanes are larger. Detonation cell sizes of PO were respectively investigated at 25°C, 35°C and 50°C with smoked foil technique. The cell width shows a U-shape curve relationship with equivalence ratios at all temperatures. The minimal cell width also lies on the rich-fuel side ( ϕ > 1). The cell width of PO vapor is slightly larger than that of PO cloud. Therefore, the detonation reaction of PO at normal temperature is controlled by gas phase reaction.

  1. Gas Transport Parameters for Landfill Final Cover Soil: Measurements and Model Modification by Dry Bulk Density

    NASA Astrophysics Data System (ADS)

    Wickramarachchi, P. N.; Kawamoto, K.; Hamamoto, S.; Nagamori, M.; Moldrup, P.; Komatsu, T.

    2011-12-01

    Landfill sites have been emerging in greenhouse warming scenarios as a significant source of atmospheric methane (CH4). Until recently, landfill management strategies have mainly addressed the problem of preventing groundwater contamination and reduction of leachate generation. Being one of the largest sources of anthropogenic CH4 emission, the final cover system should also be designed for minimizing the greenhouse gases migration into the atmosphere or the areas surrounding the landfill while securing the hydraulic performance. Compared to the intensive research efforts on hydraulic performances of landfill final cover soil, few studies about gas transport characteristics of landfill cover soils have been done. However, recent soil-gas studies implied that the effects of soil physical properties such as bulk density (i.e., compaction level), soil particle size are key parameters to understand landfill gaseous performance. The gas exchange through the final cover soils is controlled by advective and diffusive gas transport. Air permeability (ka) governs the advective gas transport while the soil-gas diffusion coefficient (Dp) governs diffusive gas transport. In this study, the effects of compaction level and particle size fraction effects on ka and Dp for landfill final cover soil was investigated. The disturbed soil samples were taken from landfill final cover in Japan. A compaction tests were performed for the soil samples with two different size fractions (< 35 mm and < 2.0 mm). In the compaction tests at field water content , the soil samples were repacked into soil cores (i.d. 15-cm, length 12-cm, 2120 cm3) at two different compaction levels [(MP):2700 kN/m2 and (SP):600 kN/m2]. After the compaction tests, ka and Dp were measured and then samples were saturated and subsequently drained at different soil-water matric potential of 0.98, 2.94, 9.81, 1235 kPa and with air-dried and oven-dried conditions. Results showed that measured Dp and ka values for the

  2. Dynamic contrast enhanced MRI parameters and tumor cellularity in a rat model of cerebral glioma at 7T

    NASA Astrophysics Data System (ADS)

    Aryal, Madhava Prasad

    -MRI-derived parameters and cell counting showed that the ve and VD were strongly correlated with tumor cellularity (r ≥ -0.75, p < 0.001 for both), however, no correlation was observed for Ktrans and vp. To conclude, this result supports the clinical utility of DCE-MRI-derived parameters for detection, staging, and evaluation of the therapeutic response on various tumors.

  3. Definition of a parameter for a typical specific absorption rate under real boundary conditions of cellular phones in a GSM networkd

    NASA Astrophysics Data System (ADS)

    Gerhardt, D.

    2003-05-01

    Using cellular phones the specific absorption rate (SAR) as a physical value must observe established and internationally defined levels to guarantee human protection. To assess human protection it is necessary to guarantee safety under worst-case conditions (especially maximum transmitting power) using cellular phones. To evaluate the exposure to electromagnetic fields under normal terms of use of cellular phones the limitations of the specific absorption rate must be pointed out. In a mobile radio network normal terms of use of cellular phones, i.e. in interconnection with a fixed radio transmitter of a mobile radio network, power control of the cellular phone as well as the antenna diagram regarding a head phantom are also significant for the real exposure. Based on the specific absorption rate, the antenna diagram regarding a head phantom and taking into consideration the power control a new parameter, the typical absorption rate (SARtyp), is defined in this contribution. This parameter indicates the specific absorption rate under average normal conditions of use. Constant radio link attenuation between a cellular phone and a fixed radio transmitter for all mobile models tested was assumed in order to achieve constant field strength at the receiving antenna of the fixed radio transmitter as a result of power control. The typical specific absorption rate is a characteristic physical value of every mobile model. The typical absorption rate was calculated for 16 different mobile models and compared with the absorption rate at maximum transmitting power. The results confirm the relevance of the definition of this parameter (SARtyp) as opposed to the specific absorption rate as a competent and applicable method to establish the real mean exposure from a cellular phone in a mobile radio network. The typical absorption rate provides a parameter to assess electromagnetic fields of a cellular phone that is more relevant to the consumer.

  4. A summary of the sources of input parameter values for the Waste Isolation Pilot Plant final porosity surface calculations

    SciTech Connect

    Butcher, B.M.

    1997-08-01

    A summary of the input parameter values used in final predictions of closure and waste densification in the Waste Isolation Pilot Plant disposal room is presented, along with supporting references. These predictions are referred to as the final porosity surface data and will be used for WIPP performance calculations supporting the Compliance Certification Application to be submitted to the U.S. Environmental Protection Agency. The report includes tables and list all of the input parameter values, references citing their source, and in some cases references to more complete descriptions of considerations leading to the selection of values.

  5. Studies on the control of plant cell enlargement by cellular parameters. Final report, July 1, 1987--June 30, 1990

    SciTech Connect

    Cleland, R.E.

    1991-12-06

    The overall goal of this grant was to conduct research that would illuminate the mechanisms by which the plant hormone auxin induces plant cells to enlarge. A large body of knowledge already existed concerning this process. To begin with, it had been demonstrated, primarily by this laboratory during previous grant periods, that the effect of auxin is to cause a loosening of the cell wall, which is followed by turgor-driven wall expansion and water uptake. The wall contains a series of load-bearing wall bonds which must be cleaved in order to loosen the wall. The identification of these load-bearing bonds is one goal of this research. We proposed that an initial action of auxin is to cause cells to excrete protons, and that the resulting acidification of the apoplast activated enzymes responsible for wall loosening. Evidence has been obtained that indicates that the proton excretion is due to an enhanced activity of the plasma membrane H{sup +} {minus}ATPase. A critical question is how auxin activates this enzyme. The third project concerned the role of wall calcium as part of load-bearing wall bonds. It has long been thought that apoplastic calcium crosslinks carboxyl groups in the wall pectic substances and stiffens the walls. We examined the role of calcium-bridges as load-bearing bonds in soybean hypocotyl cell walls in two ways. The first was to measure the viscoelastic extensibility of walls after addition of exogenous calcium or removal of endogenous calcium. The second approach was to determine if removal of wall calcium from walls while under tension resulted in wall extension, as predicted if the calcium-bridges were load-bearing bonds.

  6. TGLF Recalibration for ITER Standard Case Parameters FY2015: Theory and Simulation Performance Target Final Report

    SciTech Connect

    Candy, J.

    2015-12-01

    flows that fit the GYRO simulations, the parameters of the model had to be tuned to each case. A physics basis for the zonal flow model was lacking. Electron energy transport at short wavelength: A secondary issue – the high-k electron energy flux – was initially assumed to be independent of the zonal flow effect. However, detailed studies of the fluctuation spectra from recent multiscale (electron and ion scale) GYRO simulations provided a critical new insight into the role of zonal flows. The multiscale simulations suggested that advection by the zonal flows strongly suppressed electron-scale turbulence. Radial shear of the zonal E×B fluctuation could not compete with the large electron-scale linear growth rate, but the kx-mixing rate of the E×B advection could. This insight led to a preliminary new model for the way zonal flows saturate both electron- and ion-scale turbulence. It was also discovered that the strength of the zonal E×B velocity could be computed from the linear growth rate spectrum. The new saturation model (SAT1), which replaces the original model (SAT0), was fit to the multiscale GYRO simulations as well as the ion-scale GYRO simulations used to calibrate the original SAT0 model. Thus, SAT1 captures the physics of both multiscale electron transport and zonal-flow stabilization. In future work, the SAT1 model will require significant further testing and (expensive) calibration with nonlinear multiscale gyrokinetic simulations over a wider variety of plasma conditions – certainly more than the small set of scans about a single C-Mod L-mode discharge. We believe the SAT1 model holds great promise as a physics-based model of the multiscale turbulent transport in fusion devices. Correction to ITER performance predictions: Finally, the impact of the SAT1model on the ITER hybrid case is mixed. Without the electron-scale contribution to the fluxes, the Dimits shift makes a significant improvement in the predicted fusion power as

  7. Final Technical Report - Integrated Hydrogeophysical and Hydrogeologic Driven Parameter Upscaling for Dual-Domain Transport Modeling

    SciTech Connect

    Shafer, John M

    2012-11-05

    The three major components of this research were: 1. Application of minimally invasive, cost effective hydrogeophysical techniques (surface and borehole), to generate fine scale (~1m or less) 3D estimates of subsurface heterogeneity. Heterogeneity is defined as spatial variability in hydraulic conductivity and/or hydrolithologic zones. 2. Integration of the fine scale characterization of hydrogeologic parameters with the hydrogeologic facies to upscale the finer scale assessment of heterogeneity to field scale. 3. Determination of the relationship between dual-domain parameters and practical characterization data.

  8. Machine learning of parameter control doctrine for sensor and communication systems. Final report

    SciTech Connect

    Kamen, R.B.; Dillard, R.A.

    1988-07-01

    Artificial-intelligence approaches to learning were reviewed for their potential contributions to the construction of a system to learn parameter-control doctrine. Separate learning tasks were isolated and several levels of related problems were distinguished. Formulas for providing the learning system with measures of its performance were derived for four kinds of targets.

  9. Machine self-teaching methods for parameter optimization. Final report, October 1984-August 1986

    SciTech Connect

    Dillard, R.A.

    1986-12-01

    The problem of determining near-optimum parameter-control logic is addressed for cases where a sensor or communication system is highly flexible and the logic cannot be determined analytically. A system that supports human-like learning of optimum parameters is outlined. The major subsystems are (1) a simulation system (described for a radar example), (2) a performance monitoring system, (3) the learning system, and (4) the initial knowledge used by all subsystems. The initial knowledge is expressed modularly as specifications (e.g., radar constraints, performance measures, and target characteristics), relationships (among parameters, intermediate measures, and component performance measures), and formulas. The intent of the learning system is to relieve the human from the very tedious trial-and-error process of examining performance, selecting and applying curve-fitting methods, and selecting the next trial set of parameters. A learning system to design a simple radar meeting specific performance constraints is described in detail, for experimental purposes, in generic object-based code.

  10. The final COS-B database: In-flight calibration of instrumental parameters

    NASA Technical Reports Server (NTRS)

    Strong, A. W.; Bloemen, J. B. G. M.; Buccheri, R.; Hermsen, W.; Lebrun, F.; Mayer-Hasselwander, H. A.

    1985-01-01

    A method for the determination of temporal variation of sensitivity is designed to find a set of parameters which lead to maximum consistency between the intensities derived from different observation periods. This method is briefly described and the resulting sensitivity and background variations presented.

  11. Variational optimization of sub-grid scale convection parameters. Final report

    SciTech Connect

    Zivkovic-Rothman, M.

    1997-11-25

    Under the DOE CHAMMP/CLIMATE Program, a convective scheme was developed for use in climate models. The purpose of the present study was to develop an adjoint model of its tangent-linear model. the convective scheme was integrated within a single column model which provides radiative-convective equilibrium solutions applicable to climate models. The main goal of this part of the project was to develop an adjoint of the scheme to facilitate the optimization of its convective parameters. For that purpose, adjoint sensitivities were calculated with the adjoint code. Parameter optimization was based on TOGA COARE data which were also used in this study to obtain integrations of the nonlinear and tangent-linear models as well as the integrations of the adjoint model. Some inadequacies of the inner IFA data array were found, and did not permit a single numerical integration during the entire 4 months of data. However, reliable monthly radiative-convective equilibrium solutions and associated adjoint sensitivities were obtained and used to bring about the parameter optimization.

  12. Final Report: Geoelectrical Measurement of Multi-Scale Mass Transfer Parameters

    SciTech Connect

    Haggerty, Roy; Day-Lewis, Fred; Singha, Kamini; Johnson, Timothy; Binley, Andrew; Lane, John

    2014-03-20

    Mass transfer affects contaminant transport and is thought to control the efficiency of aquifer remediation at a number of sites within the Department of Energy (DOE) complex. An improved understanding of mass transfer is critical to meeting the enormous scientific and engineering challenges currently facing DOE. Informed design of site remedies and long-term stewardship of radionuclide-contaminated sites will require new cost-effective laboratory and field techniques to measure the parameters controlling mass transfer spatially and across a range of scales. In this project, we sought to capitalize on the geophysical signatures of mass transfer. Previous numerical modeling and pilot-scale field experiments suggested that mass transfer produces a geoelectrical signature—a hysteretic relation between sampled (mobile-domain) fluid conductivity and bulk (mobile + immobile) conductivity—over a range of scales relevant to aquifer remediation. In this work, we investigated the geoelectrical signature of mass transfer during tracer transport in a series of controlled experiments to determine the operation of controlling parameters, and also investigated the use of complex-resistivity (CR) as a means of quantifying mass transfer parameters in situ without tracer experiments. In an add-on component to our grant, we additionally considered nuclear magnetic resonance (NMR) to help parse mobile from immobile porosities. Including the NMR component, our revised study objectives were to: 1. Develop and demonstrate geophysical approaches to measure mass-transfer parameters spatially and over a range of scales, including the combination of electrical resistivity monitoring, tracer tests, complex resistivity, nuclear magnetic resonance, and materials characterization; and 2. Provide mass-transfer estimates for improved understanding of contaminant fate and transport at DOE sites, such as uranium transport at the Hanford 300 Area. To achieve our objectives, we implemented a 3

  13. Semen molecular and cellular features: these parameters can reliably predict subsequent ART outcome in a goat model

    PubMed Central

    Berlinguer, Fiammetta; Madeddu, Manuela; Pasciu, Valeria; Succu, Sara; Spezzigu, Antonio; Satta, Valentina; Mereu, Paolo; Leoni, Giovanni G; Naitana, Salvatore

    2009-01-01

    Currently, the assessment of sperm function in a raw or processed semen sample is not able to reliably predict sperm ability to withstand freezing and thawing procedures and in vivo fertility and/or assisted reproductive biotechnologies (ART) outcome. The aim of the present study was to investigate which parameters among a battery of analyses could predict subsequent spermatozoa in vitro fertilization ability and hence blastocyst output in a goat model. Ejaculates were obtained by artificial vagina from 3 adult goats (Capra hircus) aged 2 years (A, B and C). In order to assess the predictive value of viability, computer assisted sperm analyzer (CASA) motility parameters and ATP intracellular concentration before and after thawing and of DNA integrity after thawing on subsequent embryo output after an in vitro fertility test, a logistic regression analysis was used. Individual differences in semen parameters were evident for semen viability after thawing and DNA integrity. Results of IVF test showed that spermatozoa collected from A and B lead to higher cleavage rates (0 < 0.01) and blastocysts output (p < 0.05) compared with C. Logistic regression analysis model explained a deviance of 72% (p < 0.0001), directly related with the mean percentage of rapid spermatozoa in fresh semen (p < 0.01), semen viability after thawing (p < 0.01), and with two of the three comet parameters considered, i.e tail DNA percentage and comet length (p < 0.0001). DNA integrity alone had a high predictive value on IVF outcome with frozen/thawed semen (deviance explained: 57%). The model proposed here represents one of the many possible ways to explain differences found in embryo output following IVF with different semen donors and may represent a useful tool to select the most suitable donors for semen cryopreservation. PMID:19900288

  14. The effect of muscle, cooking method and final internal temperature on quality parameters of beef roast.

    PubMed

    Modzelewska-Kapituła, Monika; Dąbrowska, Ewa; Jankowska, Barbara; Kwiatkowska, Aleksandra; Cierach, Marek

    2012-06-01

    The aim of the study was to evaluate the influence of cooking conditions (dry air and steam) and final internal temperature (75, 85, 95°C) on the physico-chemical properties of beef infraspinatus (INF) and semimembranosus (SEM) muscles as well as their tenderness and juiciness. Cooking method and temperature influenced moisture, total collagen content in cooked meat and cooking loss, whereas muscle type affected fat, total collagen content and cooking loss. Warner-Bratzler shear force values were affected by cooking method, which also influenced juiciness of roasts. Temperature affected tenderness and juiciness, whereas muscle type influenced juiciness. The most desirable tenderness had INF heated in steam and dry air to 95°C. Processing SEM in dry air to 85 and 95°C lowered the juiciness of the roasts. There were significant correlations between physico-chemical, sensorial and image attributes, however high accuracy of prediction (r(2)>0.8) was achieved only for SEM muscle.

  15. Patient Protection and Affordable Care Act; HHS Notice of Benefit and Payment Parameters for 2017. Final rule.

    PubMed

    2016-03-08

    This final rule sets forth payment parameters and provisions related to the risk adjustment, reinsurance, and risk corridors programs; cost-sharing parameters and cost-sharing reductions; and user fees for Federally-facilitated Exchanges. It also provides additional amendments regarding the annual open enrollment period for the individual market for the 2017 and 2018 benefit years; essential health benefits; cost sharing; qualified health plans; Exchange consumer assistance programs; network adequacy; patient safety; the Small Business Health Options Program; stand-alone dental plans; third-party payments to qualified health plans; the definitions of large employer and small employer; fair health insurance premiums; student health insurance coverage; the rate review program; the medical loss ratio program; eligibility and enrollment; exemptions and appeals; and other related topics.

  16. Interaction between cellular voltage-sensitive conductance and network parameters in a model of neocortex can generate epileptiform bursting.

    SciTech Connect

    van Drongelen, W.; Lee, H. C.; Koch, H.; Elsen, F.; Carroll, M. S.; Hereld, M.; Stevens, R. L.; Mathematics and Computer Science; Univ. of Chicago

    2004-01-01

    We examined the effects of both intrinsic neuronal membrane properties and network parameters on oscillatory activity in a model of neocortex. A scalable network model with six different cell types was built with the pGENESIS neural simulator. The neocortical network consisted of two types of pyramidal cells and four types of inhibitory interneurons. All cell types contained both fast sodium and delayed rectifier potassium channels for generation of action potentials. A subset of the pyramidal neurons contained an additional slow inactivating (persistent) sodium current (NaP). The neurons with the NaP current showed spontaneous bursting activity in the absence of external stimulation. The model also included a routine to calculate a simulated electroencephalogram (EEG) trace from the population activity. This revealed emergent network behavior which ranged from desynchronized activity to different types of seizure-like bursting patterns. At settings with weaker excitatory network effects, the propensity to generate seizure-like behavior increased. Strong excitatory network connectivity destroyed oscillatory behavior, whereas weak connectivity enhanced the relative importance of the spontaneously bursting cells. Our findings are in contradiction with the general opinion that strong excitatory synaptic and/or insufficient inhibition effects are associated with seizure initiation, but are in agreement with previously reported behavior in neocortex.

  17. Filtered Rayleigh scattering diagnostic for multi-parameter thermal-fluids measurements : LDRD final report.

    SciTech Connect

    Beresh, Steven Jay; Grasser, Thomas W.; Kearney, Sean Patrick; Schefer, Robert W.

    2004-01-01

    Simulation-based life-cycle-engineering and the ASCI program have resulted in models of unprecedented size and fidelity. The validation of these models requires high-resolution, multi-parameter diagnostics. Within the thermal-fluids disciplines, the need for detailed, high-fidelity measurements exceeds the limits of current engineering sciences capabilities and severely tests the state of the art. The focus of this LDRD is the development and application of filtered Rayleigh scattering (FRS) for high-resolution, nonintrusive measurement of gas-phase velocity and temperature. With FRS, the flow is laser-illuminated and Rayleigh scattering from naturally occurring sources is detected through a molecular filter. The filtered transmission may be interpreted to yield point or planar measurements of three-component velocities and/or thermodynamic state. Different experimental configurations may be employed to obtain compromises between spatial resolution, time resolution, and the quantity of simultaneously measured flow variables. In this report, we present the results of a three-year LDRD-funded effort to develop FRS combustion thermometry and Aerosciences velocity measurement systems. The working principles and details of our FRS opto-electronic system are presented in detail. For combustion thermometry we present 2-D, spatially correlated FRS results from nonsooting premixed and diffusion flames and from a sooting premixed flame. The FRS-measured temperatures are accurate to within {+-}50 K (3%) in a premixed CH4-air flame and within {+-}100 K for a vortex-strained diluted CH4-air diffusion flame where the FRS technique is severely tested by large variation in scattering cross section. In the diffusion flame work, FRS has been combined with Raman imaging of the CH4 fuel molecule to correct for the local light scattering properties of the combustion gases. To our knowledge, this is the first extension of FRS to nonpremixed combustion and the first use of joint FRS

  18. Exposure of Daphnia magna to trichloroethylene (TCE) and vinyl chloride (VC): evaluation of gene transcription, cellular activity, and life-history parameters.

    PubMed

    Houde, Magali; Douville, Mélanie; Gagnon, Pierre; Sproull, Jim; Cloutier, François

    2015-06-01

    Trichloroethylene (TCE) is a ubiquitous contaminant classified as a human carcinogen. Vinyl chloride (VC) is primarily used to manufacture polyvinyl chloride and can also be a degradation product of TCE. Very few data exist on the toxicity of TCE and VC in aquatic organisms particularly at environmentally relevant concentrations. The aim of this study was to evaluate the sub-lethal effects (10 day exposure; 0.1; 1; 10 µg/L) of TCE and VC in Daphnia magna at the gene, cellular, and life-history levels. Results indicated impacts of VC on the regulation of genes related to glutathione-S-transferase (GST), juvenile hormone esterase (JHE), and the vitelline outer layer membrane protein (VMO1). On the cellular level, exposure to 0.1, 1, and 10 µg/L of VC significantly increased the activity of JHE in D. magna and TCE increased the activity of chitinase (at 1 and 10 µg/L). Results for life-history parameters indicated a possible tendency of TCE to affect the number of molts at the individual level in D. magna (p=0.051). Measurement of VG-like proteins using the alkali-labile phosphates (ALP) assay did not show differences between TCE treated organisms and controls. However, semi-quantitative measurement using gradient gel electrophoresis (213-218 kDa) indicated significant decrease in VG-like protein levels following exposure to TCE at all three concentrations. Overall, results indicate effects of TCE and VC on genes and proteins related to metabolism, reproduction, and growth in D. magna.

  19. Medium energy measurements of N-N parameters. Final technical report, April 1, 1994--September 30, 1996

    SciTech Connect

    Ambrose, D.; Betts, W.; Coffey, P.; Glass, G.; McDonough, J.; Riley, P.; Tang, J.L.

    1998-08-01

    This document is a final technical report describing the accomplishments of the medium/high energy nuclear physics research program at the University of Texas at Austin. The research program had four main thrusts, only one of which can be considered as measurements of N-N parameters: (1) finishing the data analyses associated with recent LAMPF and TRIUMPF N-N experiments, whose overall purpose has been the determination of the nucleon-nucleon amplitudes, both for isospin 0 and 1 at medium energies; (2) continuing work on BNL E871, a search for rare decay modes of the K{sub L}; (3) work on the RHIC-STAR project, an experiment to create and study a quark gluon plasma and nuclear matter at high energy density; (4) beginning a new AGS experiment (E896) which will search for the lowest mass state of the predicted strange di-baryons, the Ho, and other exotic states of nuclear matter through nucleus-nucleus collisions.

  20. Comparative study of effects of magnesium and taurine on electrical parameters of natural and artificial membranes. VII. Effects on cellular and paracellular ionic transfer through isolated human amnion.

    PubMed

    Bara, M; Guiet-Bara, A; Durlach, J

    1990-12-01

    The comparative effects of 2 mM magnesium and taurine on various components of the human transamniotic conductance, Gt, were observed. The use of both microelectrodes and metabolic inhibitors enables 10 components of Gt to be distinguished: six cellular components (Na-K ATPase, Na-H antiport, Na-K-2Cl cotransport and Na, K, Cl channels), one coupling component, and three paracellular components (Na, K, Cl). Mg increased all components of Gt while taurine only increased five of them (Na and K channels, coupling, Na and K paracellular conductance). A potentiometric effect of taurine on Mg2+ modified membrane, obtained on paracellular components, was not measured on cellular components. There was only a vicarious effect between Mg and taurine on the non-enzymatic cellular and paracellular transfer of Na and K.

  1. Investigation of the use of fly-ash based autoclaved cellular concrete blocks in coal mines for air duct work. Final report, January 25, 1993--December 31, 1994

    SciTech Connect

    Horvath, M.L.

    1995-06-19

    Coal mines are required to provide ventilation to occupied portions of underground mines. Concrete block is used in this process to construct air duct walls. However, normal concrete block is heavy and not easy to work with and eventually fails dramatically after being loaded due to mine ceiling convergence and/or floor heave. Autoclaved cellular concrete block made from (70{plus_minus}%) coal fly ash is lightweight and less rigid when loaded. It is lighter and easier to use than regular concrete block for underground mine applications. It has also been used in surface construction around the world for over 40 years. Ohio Edison along with eight other electric utility companies, the Electric Power Research Institute (EPRI), and North American Cellular Concrete constructed a mobile demonstration plant to produce autoclaved cellular concrete block from utility fly ash. To apply this research in Ohio, Ohio Edison also worked with the Ohio Coal Development Office and CONSOL Inc. to produce autoclaved cellular concrete block not only from coal ash but also from LIMB ash, SNRB ash, and PFBC ash from various clean coal technology projects sponsored by the Ohio Coal Development Office. The purpose of this project was to demonstrate the potential for beneficial use of fly ash and clean coal technology by-products in the production of lightweight block.

  2. High frequency 3-component waveform inversion for source and structural parameters. Final report, 31 December 1993--30 June 1998

    SciTech Connect

    Harvey, D.J.; Lavehio, A.L.

    1998-09-01

    The authors present the results of three studies to develop and verify techniques to classify weak seismic events. (1) The method and results of full waveform inversion for both detailed source parameters and structure parameters are described. Input data were seismograms from industrial explosions in Eastern Kazakhstan recorded by the NRDC seismic network in 1987. Very good fits were produced between the synthetic seismograms and the observed data on all three components simultaneously and for P-wave, Rayleigh wave, and Love wave. They interpreted some of the inverted source parameters as characteristic of several different types of industrial surface mining operations. (2) The same technique was used to determine detailed source and structure parameters using an event that is highly relevant to nuclear monitoring. They determined that a salt mine collapse near Solikamsk, the Ural Mountains on 5 January 1995 was most likely a mine collapse instead of an underground explosions. (3) This study was carried out jointly by the Seismology Group of the University of Colorado and the Russian team from the Int`l Institute of Earthquake Prediction Theory and Math. Geophysics. They developed a new technique to identify a seismic event based on simultaneous inversion of surface wave amplitude spectra and signs of first motions of body wave. They applied this technique to several events near the Chinese test site at Lop Nor and demonstrated significant differences in source parameters characterizing explosions and natural earthquakes in this region.

  3. Geoelectrical Measurement of Multi-Scale Mass Transfer Parameters Final Report to the Subsurface Biogeochemical Research Program

    SciTech Connect

    Day-Lewis, Frederick; Singha, Kamini; Haggerty, Roy; Johnson, Timothy; Binley, Andrew; Lane, John

    2014-03-10

    . In this project, we sought to capitalize on the geophysical signatures of mass transfer. Previous numerical modeling and pilot-scale field experiments suggested that mass transfer produces a geoelectrical signature—a hysteretic relation between sampled (mobile-domain) fluid conductivity and bulk (mobile + immobile) conductivity—over a range of scales relevant to aquifer remediation. In this work, we investigated the geoelectrical signature of mass transfer during tracer transport in a series of controlled experiments to determine the operation of controlling parameters, and also investigated the use of complex-resistivity (CR) as a means of quantifying mass transfer parameters in situ without tracer experiments. In an add-on component to our grant, we additionally considered nuclear magnetic resonance (NMR) to help parse mobile from immobile porosities. Our study objectives were to: 1. Develop and demonstrate geophysical approaches to measure mass-transfer parameters spatially and over a range of scales, including the combination of electrical resistivity monitoring, tracer tests, complex resistivity, nuclear magnetic resonance, and materials characterization; and 2. Provide mass-transfer estimates for improved understanding of contaminant fate and transport at DOE sites, such as uranium transport at the Hanford 300 Area. To achieve our objectives, we implemented a 3-part research plan involving (1) development of computer codes and techniques to estimate mass-transfer parameters from time-lapse electrical data; (2) bench-scale experiments on synthetic materials and materials from cores from the Hanford 300 Area; and (3) field demonstration experiments at the DOE’s Hanford 300 Area.

  4. Maximum safe pulling lengths for solid dielectric insulated cables. Volume 1. Research data and cable-pulling parameters. Final report

    SciTech Connect

    Silver, D.A.; Seman, G.W.; Bush, R.A.; Matthews, G.H.

    1984-02-01

    This two-volume report presents the results of a recent program to investigate and update the parameters that affect the maximum safe pulling length for solid dielectric cables. In this program, 23 types of solid dielectric cables rated 600 V through 138 kV were studied. The cables had copper and aluminum conductors in sizes from 1/0 AWG (54 mm/sup 2/) to 2500 kcmil (1266 mm/sup 2/) and insulations of cross-linked polyethylene and ethylene propylene rubber.

  5. Current good tissue practice for human cell, tissue, and cellular and tissue-based product establishments; inspection and enforcement. Final rule.

    PubMed

    2004-11-24

    The Food and Drug Administration (FDA) is requiring human cell, tissue, and cellular and tissue-based product (HCT/P) establishments to follow current good tissue practice (CGTP), which governs the methods used in, and the facilities and controls used for, the manufacture of HCT/Ps; recordkeeping; and the establishment of a quality program. The agency is also issuing new regulations pertaining to labeling, reporting, inspections, and enforcement that will apply to manufacturers of those HCT/Ps regulated solely under the authority of the Public Health Service Act (PHS Act), and not as drugs, devices, and/or biological products. The agency's actions are intended to improve protection of the public health while keeping regulatory burden to a minimum, which in turn would encourage significant innovation.

  6. Multifaceted interplay between lipophilicity, protein interaction and luminescence parameters of non-intercalative ruthenium(II) polypyridyl complexes controlling cellular imaging and cytotoxic properties.

    PubMed

    Mazuryk, Olga; Magiera, Katarzyna; Rys, Barbara; Suzenet, Franck; Kieda, Claudine; Brindell, Małgorzata

    2014-12-01

    Here, we examine the photophysical properties of five ruthenium(II) complexes comprising two 4,7-diphenyl-1,10-phenanthroline (dip) ligands and functionalized bipyridine (R₁bpy-R₂, where R₁= H or CH3, R₂= H, CH₃, COO⁻,4-[3-(2-nitro-1H-imidazol-1-yl)propyl] or 1,3-dicyclohexyl-1-carbonyl-urea) towards development of luminescence probes for cellular imaging. These complexes have been shown to interact with albumin and the formed adducts exhibited up to eightfold increase in the luminescence quantum yield as well as the average lifetime of emission. It was demonstrated that they cannot bind to DNA through the intercalation mode and its luminescence in the presence of DNA is quenching. Cell viability experiments indicated that all complexes possess significant dose-dependent cytotoxicity (with IC₅₀ 5-19 μM) on 4T1 breast cancer cell line and their anti-proliferative activity correlates very well with their lipophilicity. Cellular uptake was studied by measuring the ruthenium content in cells using ICP-MS technique. As expected, the better uptake is directly related to higher lipophilicity of doubly charged ruthenium complexes while uptake of monocationic one is much lower in spite of the highest lipophilicity. Additionally staining properties were assessed using flow cytometry and fluorescence microscopy. These experiments showed that complex with 1,3-dicyclohexyl-1-carbonyl-urea substituent exhibits the best staining properties in spite of the lowest luminescence quantum yield in buffered solution (pH 7.4). Our results point out that both the imaging and cytotoxic properties of the studied ruthenium complexes are strongly influence by the level of internalization and protein interaction.

  7. Final Report for Grant No. DE-FG02-01ER63220 "The Dynamics of Cellular Stress Responses in Deinococcus radiodurans"

    SciTech Connect

    PI: Michael J. Daly, Ph.D., Uniformed Services University of the Health Sciences; Co-Investigators: James K. Fredrickson, Ph.D., Pacific Northwest National Laboratory; Richard D. Smith, Ph.D., Pacific Northwest National Laboratory; Eugene Koonin, Ph.D., National Center for Biotechnology Information; Jizhong Zhou, Ph.D. , Oak Ridge National Laboratory; Mary S. Lipton, Ph.D., Pacific Northwest National Laboratory

    2006-03-06

    Bacteria belonging to the family Deinococcaceae are some of the most ionizing radiation (IR) resistant organisms yet discovered. Deinococcus radiodurans is obligate aerobic, capable of growth under chronic IR (60 Gy/hour) and relatively resistant to many DNA damaging conditions including exposure to desiccation, ultraviolet radiation and hydrogen peroxide. The genes and cellular pathways underlying the survival strategies of D. radiodurans have been under investigation for fifty years. In the last decade, D. radiodurans was subjected to whole-genome sequencing, annotation and comparative analysis, whole-transcriptome and whole-proteome analyses, and numerous DNA repair studies. Collectively, published reports support that the key to survival of D. radiodurans resides in its ability to repair DNA, but the mechanisms responsible remain poorly defined. Unexpectedly, many novel genes implicated in recovery from IR by transcriptome and proteome profiling have had little effect on survival when disrupted, and there is reason to ask if something is missing from classical models of radiation resistance. The prevailing dogma of radiation toxicity has been that the cytotoxic and mutagenic effects of radiation are principally the result of DNA damage that occurs during IR. However, in light of available whole genome sequences, one broad observation that is difficult to reconcile with this view is that many organisms that encode a compliment of DNA repair and protection functions are killed at radiation doses that cause little DNA damage. This indicates that there are cellular targets involved in recovery that are more vulnerable to IR damage than DNA. It has been reported that D. radiodurans and other resistant organisms accumulate very high intracellular concentrations of Mn(II), and restricting the amount of Mn(II) during recovery from IR substantially reduced survival of D. radiodurans. At high intracellular concentrations, Mn(II) is known to act as a true catalyst of the

  8. In-situ parameter estimation for solar domestic hot water heating systems components. Final report, June 1995--May 1996

    SciTech Connect

    Smith, T.R.

    1997-03-01

    Three different solar domestic hot water systems are being tested at the Colorado State University Solar Energy Applications Laboratory; an unpressurized drain-back system with a load side heat exchanger, an integral collector storage system, and an ultra low flow natural convection heat exchanger system. The systems are fully instrumented to yield data appropriate for in-depth analyses of performance. The level of detail allows the observation of the performance of the total system and the performance of the individual components. This report evaluates the systems based on in-situ experimental data and compares the performances with simulated performances. The verification of the simulations aids in the rating procedure. The whole system performance measurements are also used to analyze the performance of individual components of a solar hot water system and to develop improved component models. The data are analyzed extensively and the parameters needed to characterize the systems fully are developed. Also resulting from this indepth analysis are suggested design improvements wither to the systems or the system components.

  9. SU-E-T-667: Radiosensitization Due to Gold Nanoparticles: A Monte Carlo Cellular Dosimetry Investigation of An Expansive Parameter Space

    SciTech Connect

    Martinov, M; Thomson, R

    2015-06-15

    Purpose: To investigate dose enhancement to cellular compartments following gold nanoparticle (GNP) uptake in tissue, varying cell and tissue morphology, intra and extracellular GNP distribution, and source energy using Monte Carlo (MC) simulations. Methods: Models of single and multiple cells are developed for normal and cancerous tissues; cells (outer radii 5–10 µm) are modeled as concentric spheres comprising the nucleus (radii 2.5–7.5 µm) and cytoplasm. GNP distributions modeled include homogeneous distributions throughout the cytoplasm, variable numbers of GNP-containing endosomes within the cytoplasm, or distributed in a spherical shell about the nucleus. Gold concentrations range from 1 to 30 mg/g. Dose to nucleus and to cytoplasm for simulations including GNPs are compared to simulations without GNPs to compute Nuclear and Cytoplasm Dose Enhancement Factors (NDEF, CDEF). Photon source energies are between 20 keV and 1.25 MeV. Results: DEFs are highly sensitive to GNP intracellular distribution; for a 2.5 µm radius nucleus irradiated by a 30 keV source, NDEF varies from 1.2 for a single endosome containing all GNPs to 8.2 for GNPs distributed about the nucleus (7 mg/g). DEFs vary with cell dimensions and source energy: NDEFs vary from 2.5 (90 keV) to 8.2 (30 keV) for a 2.5 µm radius nucleus and from 1.1 (90 keV) to 1.3 (30 keV) for a 7.5 µm radius nucleus, both with GNPs in a spherical shell about the nucleus (7 mg/g). NDEF and CDEF are generally different within a single cell. For multicell models, the presence of gold within intervening tissues between source and target perturbs the fluence reaching cellular targets, resulting in DEF inhomogeneities within a population of irradiated cells. Conclusion: DEFs vary by an order of magnitude for different cell models, GNP distributions, and source energies, demonstrating the importance of detailed modelling for advancing GNP development for radiotherapy. Funding provided by the Natural Sciences and

  10. Final Report for NFE-07-00912: Development of Model Fuels Experimental Engine Data Base & Kinetic Modeling Parameter Sets

    SciTech Connect

    Bunting, Bruce G

    2012-10-01

    The automotive and engine industries are in a period of very rapid change being driven by new emission standards, new types of after treatment, new combustion strategies, the introduction of new fuels, and drive for increased fuel economy and efficiency. The rapid pace of these changes has put more pressure on the need for modeling of engine combustion and performance, in order to shorten product design and introduction cycles. New combustion strategies include homogeneous charge compression ignition (HCCI), partial-premixed combustion compression ignition (PCCI), and dilute low temperature combustion which are being developed for lower emissions and improved fuel economy. New fuels include bio-fuels such as ethanol or bio-diesel, drop-in bio-derived fuels and those derived from new crude oil sources such as gas-to-liquids, coal-to-liquids, oil sands, oil shale, and wet natural gas. Kinetic modeling of the combustion process for these new combustion regimes and fuels is necessary in order to allow modeling and performance assessment for engine design purposes. In this research covered by this CRADA, ORNL developed and supplied experimental data related to engine performance with new fuels and new combustion strategies along with interpretation and analysis of such data and consulting to Reaction Design, Inc. (RD). RD performed additional analysis of this data in order to extract important parameters and to confirm engine and kinetic models. The data generated was generally published to make it available to the engine and automotive design communities and also to the Reaction Design Model Fuels Consortium (MFC).

  11. Lack of effects on key cellular parameters of MRC-5 human lung fibroblasts exposed to 370 mT static magnetic field.

    PubMed

    Romeo, Stefania; Sannino, Anna; Scarfì, Maria Rosaria; Massa, Rita; d'Angelo, Raffaele; Zeni, Olga

    2016-01-14

    The last decades have seen increased interest toward possible adverse effects arising from exposure to intense static magnetic fields. This concern is mainly due to the wider and wider applications of such fields in industry and clinical practice; among them, Magnetic Resonance Imaging (MRI) facilities are the main sources of exposure to static magnetic fields for both general public (patients) and workers. In recent investigations, exposures to static magnetic fields have been demonstrated to elicit, in different cell models, both permanent and transient modifications in cellular endpoints critical for the carcinogenesis process. The World Health Organization has therefore recommended in vitro investigations as important research need, to be carried out under strictly controlled exposure conditions. Here we report on the absence of effects on cell viability, reactive oxygen species levels and DNA integrity in MRC-5 human foetal lung fibroblasts exposed to 370 mT magnetic induction level, under different exposure regimens. Exposures have been performed by using an experimental apparatus designed and realized for operating with the static magnetic field generated by permanent magnets, and confined in a magnetic circuit, to allow cell cultures exposure in absence of confounding factors like heating or electric field components.

  12. Lack of effects on key cellular parameters of MRC-5 human lung fibroblasts exposed to 370 mT static magnetic field

    PubMed Central

    Romeo, Stefania; Sannino, Anna; Scarfì, Maria Rosaria; Massa, Rita; d’Angelo, Raffaele; Zeni, Olga

    2016-01-01

    The last decades have seen increased interest toward possible adverse effects arising from exposure to intense static magnetic fields. This concern is mainly due to the wider and wider applications of such fields in industry and clinical practice; among them, Magnetic Resonance Imaging (MRI) facilities are the main sources of exposure to static magnetic fields for both general public (patients) and workers. In recent investigations, exposures to static magnetic fields have been demonstrated to elicit, in different cell models, both permanent and transient modifications in cellular endpoints critical for the carcinogenesis process. The World Health Organization has therefore recommended in vitro investigations as important research need, to be carried out under strictly controlled exposure conditions. Here we report on the absence of effects on cell viability, reactive oxygen species levels and DNA integrity in MRC-5 human foetal lung fibroblasts exposed to 370 mT magnetic induction level, under different exposure regimens. Exposures have been performed by using an experimental apparatus designed and realized for operating with the static magnetic field generated by permanent magnets, and confined in a magnetic circuit, to allow cell cultures exposure in absence of confounding factors like heating or electric field components. PMID:26762783

  13. Lack of effects on key cellular parameters of MRC-5 human lung fibroblasts exposed to 370 mT static magnetic field

    NASA Astrophysics Data System (ADS)

    Romeo, Stefania; Sannino, Anna; Scarfì, Maria Rosaria; Massa, Rita; D’Angelo, Raffaele; Zeni, Olga

    2016-01-01

    The last decades have seen increased interest toward possible adverse effects arising from exposure to intense static magnetic fields. This concern is mainly due to the wider and wider applications of such fields in industry and clinical practice; among them, Magnetic Resonance Imaging (MRI) facilities are the main sources of exposure to static magnetic fields for both general public (patients) and workers. In recent investigations, exposures to static magnetic fields have been demonstrated to elicit, in different cell models, both permanent and transient modifications in cellular endpoints critical for the carcinogenesis process. The World Health Organization has therefore recommended in vitro investigations as important research need, to be carried out under strictly controlled exposure conditions. Here we report on the absence of effects on cell viability, reactive oxygen species levels and DNA integrity in MRC-5 human foetal lung fibroblasts exposed to 370 mT magnetic induction level, under different exposure regimens. Exposures have been performed by using an experimental apparatus designed and realized for operating with the static magnetic field generated by permanent magnets, and confined in a magnetic circuit, to allow cell cultures exposure in absence of confounding factors like heating or electric field components.

  14. L-DOPA-induced dyskinesia in the intrastriatal 6-hydroxydopamine model of parkinson's disease: relation to motor and cellular parameters of nigrostriatal function.

    PubMed

    Winkler, Christian; Kirik, Deniz; Björklund, Anders; Cenci, M Angela

    2002-07-01

    In order to assess the role of striatal dopamine (DA) afferents in L-DOPA-induced dyskinesia, we have studied a large series of rats sustaining 2, 3, or 4 unilateral injections of 6-hydroxydopamine (6-OHDA) in the lateral striatum. This type of lesion produced a dose-dependent depletion of DA fibers in the caudate-putamen, which was most pronounced in the lateral aspects of this structure. An additional group of rats was injected with 6-OHDA in the medial forebrain bundle to obtain complete DA denervation on one side of the brain. During a course of chronic L-DOPA treatment, rats with intrastriatal 6-OHDA lesions developed abnormal involuntary movements (AIMs), which mapped onto striatal domains exhibiting at least approximately 90% denervation, as judged by DA transporter autoradiography. The denervated areas showed local upregulation of preproenkephalin and prodynorphin mRNA, and FosB-like immunoreactivity, which were highly correlated with the rats' AIM scores. When compared to completely DA-denervated animals, the rats with intrastriatal 6-OHDA lesions showed an overall lower incidence, lower severity and different topographic distribution of AIMs. The involvement of proximal limb and axial muscles in the abnormal movements was proportional to the spreading of the lesion from lateral towards medial aspects of the caudate-putamen. Locomotive AIMs were only seen in rats with complete lesions, but not in any of the animals with intrastriatal 6-OHDA (which showed > 5% DA fiber sparing in the medial striatum). Intrastriatally 6-OHDA-lesioned rats had a larger therapeutic window for L-DOPA than did rats with complete bundle lesions, since they exhibited an overall lower predisposition to dyskinesia but a similar degree of drug-induced motor improvement in a test of forelimb stepping. Our results are the first to demonstrate that selective and partial DA denervation in the sensorimotor part of the striatum can confer cellular and behavioral supersensitivity to L

  15. Early differential cell death and survival mechanisms initiate and contribute to the development of OPIDN: A study of molecular, cellular, and anatomical parameters

    SciTech Connect

    Damodaran, T.V.; Attia, M.K.; Abou-Donia, M.B.

    2011-11-15

    analysis revealed that the order of severity of damage declines from the spino-cerebellar, ventral, and dorsal tract respectively, suggesting neuroanatomical specificity. Thus, early activation of cell death and cell survival processes may play significant role in the clinical progression and syndromic clinical feature presentation of OPIDN. -- Highlights: Black-Right-Pointing-Pointer Multiple mechanisms of neurodegeneration were indicated in a study on OPIDN model. Black-Right-Pointing-Pointer Altered expressions of BCL2 and GADD45 were recorded in various tissues of CNS. Black-Right-Pointing-Pointer Multiple anomalous cellular (neuronal and astroglial) features were recorded. Black-Right-Pointing-Pointer Anatomical specificity of the neurodegeneration was described.

  16. In1-ghrelin, a splice variant of ghrelin gene, is associated with the evolution and aggressiveness of human neuroendocrine tumors: Evidence from clinical, cellular and molecular parameters.

    PubMed

    Luque, Raul M; Sampedro-Nuñez, Miguel; Gahete, Manuel D; Ramos-Levi, Ana; Ibáñez-Costa, Alejandro; Rivero-Cortés, Esther; Serrano-Somavilla, Ana; Adrados, Magdalena; Culler, Michael D; Castaño, Justo P; Marazuela, Mónica

    2015-08-14

    Ghrelin system comprises a complex family of peptides, receptors (GHSRs), and modifying enzymes [e.g. ghrelin-O-acyl-transferase (GOAT)] that control multiple pathophysiological processes. Aberrant alternative splicing is an emerging cancer hallmark that generates altered proteins with tumorigenic capacity. Indeed, In1-ghrelin and truncated-GHSR1b splicing variants can promote development/progression of certain endocrine-related cancers. Here, we determined the expression levels of key ghrelin system components in neuroendocrine tumor (NETs) and explored their potential functional role. Twenty-six patients with NETs were prospectively/retrospectively studied [72 samples from primary and metastatic tissues (30 normal/42 tumors)] and clinical data were obtained. The role of In1-ghrelin in aggressiveness was studied in vitro using NET cell lines (BON-1/QGP-1). In1-ghrelin, GOAT and GHSR1a/1b expression levels were elevated in tumoral compared to normal/adjacent tissues. Moreover, In1-ghrelin, GOAT, and GHSR1b expression levels were positively correlated within tumoral, but not within normal/adjacent samples, and were higher in patients with progressive vs. with stable/cured disease. Finally, In1-ghrelin increased aggressiveness (e.g. proliferation/migration) of NET cells. Altogether, our data strongly suggests a potential implication of ghrelin system in the pathogenesis and/or clinical outcome of NETs, and warrant further studies on their possible value for the future development of molecular biomarkers with diagnostic/prognostic/therapeutic value.

  17. In1-ghrelin, a splice variant of ghrelin gene, is associated with the evolution and aggressiveness of human neuroendocrine tumors: Evidence from clinical, cellular and molecular parameters

    PubMed Central

    Gahete, Manuel D.; Ramos-Levi, Ana; Ibáñez-Costa, Alejandro; Rivero-Cortés, Esther; Serrano-Somavilla, Ana; Adrados, Magdalena; Culler, Michael D.; Castaño, Justo P.; Marazuela, Mónica

    2015-01-01

    Ghrelin system comprises a complex family of peptides, receptors (GHSRs), and modifying enzymes [e.g. ghrelin-O-acyl-transferase (GOAT)] that control multiple pathophysiological processes. Aberrant alternative splicing is an emerging cancer hallmark that generates altered proteins with tumorigenic capacity. Indeed, In1-ghrelin and truncated-GHSR1b splicing variants can promote development/progression of certain endocrine-related cancers. Here, we determined the expression levels of key ghrelin system components in neuroendocrine tumor (NETs) and explored their potential functional role. Twenty-six patients with NETs were prospectively/retrospectively studied [72 samples from primary and metastatic tissues (30 normal/42 tumors)] and clinical data were obtained. The role of In1-ghrelin in aggressiveness was studied in vitro using NET cell lines (BON-1/QGP-1). In1-ghrelin, GOAT and GHSR1a/1b expression levels were elevated in tumoral compared to normal/adjacent tissues. Moreover, In1-ghrelin, GOAT, and GHSR1b expression levels were positively correlated within tumoral, but not within normal/adjacent samples, and were higher in patients with progressive vs. with stable/cured disease. Finally, In1-ghrelin increased aggressiveness (e.g. proliferation/migration) of NET cells. Altogether, our data strongly suggests a potential implication of ghrelin system in the pathogenesis and/or clinical outcome of NETs, and warrant further studies on their possible value for the future development of molecular biomarkers with diagnostic/prognostic/therapeutic value. PMID:26124083

  18. Approaches to Biosimulation of Cellular Processes

    PubMed Central

    Westerhoff, H. V.

    2006-01-01

    Modelling and simulation are at the heart of the rapidly developing field of systems biology. This paper reviews various types of models, simulation methods, and theoretical approaches that are presently being used in the quantitative description of cellular processes. We first describe how molecular interaction networks can be represented by means of stoichiometric, topological and kinetic models. We briefly discuss the formulation of kinetic models using mesoscopic (stochastic) or macroscopic (continuous) approaches, and we go on to describe how detailed models of molecular interaction networks (silicon cells) can be constructed on the basis of experimentally determined kinetic parameters for cellular processes. We show how theory can help in analyzing models by applying control analysis to a recently published silicon cell model. Finally, we review some of the theoretical approaches available to analyse kinetic models and experimental data, respectively. PMID:19669467

  19. A two parameter family of travelling waves with a singular barrier arising from the modelling of extracellular matrix mediated cellular invasion

    NASA Astrophysics Data System (ADS)

    Perumpanani, Abbey J.; Sherratt, Jonathan A.; Norbury, John; Byrne, Helen M.

    1999-02-01

    Invasive cells variously show changes in adhesion, protease production and motility. In this paper the authors develop and analyse a model for malignant invasion, brought about by a combination of proteolysis and haptotaxis. A common feature of these two mechanisms is that they can be produced by contact with the extracellular matrix through the mediation of a class of surface receptors called integrins. An unusual feature of the model is the absence of cell diffusion. By seeking travelling wave solutions the model is reduced to a system of ordinary differential equations which can be studied using phase plane analysis. The authors demonstrate the presence of a singular barrier in the phase plane and a “hole” in this singular barrier which admits a phase trajectory. The model admits a family of travelling waves which depend on two parameters, i.e. the tissue concentration of connective tissue and the rate of decay of the initial spatial profile of the invading cells. The slowest member of this family corresponds to the phase trajectory which goes through the “hole” in the singular barrier. Using a power series method the authors derive an expression relating the minimum wavespeed to the tissue concentration of the extracellular matrix which is arbitrary. The model is applicable in a wide variety of biological settings which combine haptotaxis with proteolysis. By considering various functional forms the authors show that the key mathematical features of the particular model studied in the early parts of the paper are exhibited by a wider class of models which characterise the behaviour of invading cells.

  20. Matrix and Backstage: Cellular Substrates for Viral Vaccines

    PubMed Central

    Jordan, Ingo; Sandig, Volker

    2014-01-01

    Vaccines are complex products that are manufactured in highly dynamic processes. Cellular substrates are one critical component that can have an enormous impact on reactogenicity of the final preparation, level of attenuation of a live virus, yield of infectious units or antigens, and cost per vaccine dose. Such parameters contribute to feasibility and affordability of vaccine programs both in industrialized countries and developing regions. This review summarizes the diversity of cellular substrates for propagation of viral vaccines from primary tissue explants and embryonated chicken eggs to designed continuous cell lines of human and avian origin. PMID:24732259

  1. Optimization of Fluorescence Assay of Cellular Manganese Status for High Throughput Screening

    PubMed Central

    Kumar, Kevin K.; Aboud, Asad A.; Patel, Devin K.; Aschner, Michael; Bowman, Aaron B.

    2013-01-01

    The advent of high throughput screening (HTS) technology permits identification of compounds that influence various cellular phenotypes. However, screening for small molecule chemical modifiers of neurotoxicants has been limited by the scalability of existing phenotyping assays. Furthermore, the adaptation of existing cellular assays to HTS format requires substantial modification of experimental parameters and analysis methodology to meet the necessary statistical requirements. Here we describe the successful optimization of the Cellular Fura-2 Manganese Extraction Assay (CFMEA) for HTS. By optimizing cellular density, manganese (Mn) exposure conditions, and extraction parameters, the sensitivity and dynamic range of the fura-2 Mn response was enhanced to permit detection of positive and negative modulators of cellular manganese status. Finally, we quantify and report strategies to control sources of intra-and inter-plate variability by batch level and plate-geometric level analysis. Our goal is to enable HTS with the CFMEA to identify novel modulators of Mn transport. PMID:23169769

  2. Fatigue of cellular materials

    SciTech Connect

    Huang, J.S.; Lin, J.Y.

    1996-01-01

    The fatigue of cellular materials is analyzed using dimensional arguments. When the first unbroken cell wall ahead of the macrocrack tip fails after some cycles of loading, the macrocrack advances one cell diameter, giving the macrocrack growth rate of cellular materials. Paris law for microcrack propagation, Basquin law for high cycle fatigue and Coffin-Manson law for low cycle fatigue are employed in calculating the number of cycles to failure of the first unbroken cell wall ahead of the macrocrack tip. It is found that fatigue of cellular materials depends on cyclic stress intensity range, cell size, relative density and the fatigue parameters of the solid from which they are made. Theoretical modelling of fatigue of foams is compared to data in polymer foams; agreement is good.

  3. Critical modeling parameters identified for 3D CFD modeling of rectangular final settling tanks for New York City wastewater treatment plants.

    PubMed

    Ramalingam, K; Xanthos, S; Gong, M; Fillos, J; Beckmann, K; Deur, A; McCorquodale, J A

    2012-01-01

    New York City Environmental Protection is in the process of incorporating biological nitrogen removal (BNR) in its wastewater treatment plants (WWTPs) which entails operating the aeration tanks with higher levels of mixed liquor suspended solids (MLSS) than a conventional activated sludge process. The objective of this paper is to discuss two of the important parameters introduced in the 3D CFD model that has been developed by the City College of New York (CCNY) group: (a) the development of the 'discrete particle' measurement technique to carry out the fractionation of the solids in the final settling tank (FST) which has critical implications in the prediction of the effluent quality; and (b) the modification of the floc aggregation (K(A)) and floc break-up (K(B)) coefficients that are found in Parker's flocculation equation (Parker et al. 1970, 1971) used in the CFD model. The dependence of these parameters on the predictions of the CFD model will be illustrated with simulation results on one of the FSTs at the 26th Ward WWTP in Brooklyn, NY.

  4. Cellular and Molecular Parameters of Mesothelioma

    PubMed Central

    Ramos-Nino, Maria E.; Testa, Joseph R.; Altomare, Deborah A.; Pass, Harvey I.; Carbone, Michele; Bocchetta, Maurizio; Mossman, Brooke T.

    2009-01-01

    Malignant mesotheliomas (MM) are neoplasms arising from mesothelial cells that line the body cavities, most commonly the pleural and peritoneal cavities. Although traditionally recognized as associated with occupational asbestos exposures, MMs can appear in individuals with no documented exposures to asbestos fibers, and emerging data suggest that genetic susceptibility and simian virus 40 (SV40) infections also facilitate the development of MMs. Both asbestos exposure and transfection of human mesothelial cells with SV40 large and small antigens (Tag, tag) cause genetic modifications and cell signaling events, most notably the induction of cell survival pathways and activation of receptors, and other proteins that favor the growth and establishment of MMs as well as their resistance to chemotherapy. Recent advances in high-throughput technologies documenting gene and protein expression in patients and animal models of MMs can now be validated in human MM tissue arrays. These have revealed expression profiles that allow more accurate diagnosis and prognosis of MMs. More importantly, serum proteomics has revealed two new candidates (osteopontin and serum mesothelin-related protein or SMRP) potentially useful in screening individuals for MMs. These mechanistic approaches offer new hope for early detection and treatment of these devastating tumors. PMID:16795078

  5. Agent-Based Modeling of Mitochondria Links Sub-Cellular Dynamics to Cellular Homeostasis and Heterogeneity.

    PubMed

    Dalmasso, Giovanni; Marin Zapata, Paula Andrea; Brady, Nathan Ryan; Hamacher-Brady, Anne

    2017-01-01

    Mitochondria are semi-autonomous organelles that supply energy for cellular biochemistry through oxidative phosphorylation. Within a cell, hundreds of mobile mitochondria undergo fusion and fission events to form a dynamic network. These morphological and mobility dynamics are essential for maintaining mitochondrial functional homeostasis, and alterations both impact and reflect cellular stress states. Mitochondrial homeostasis is further dependent on production (biogenesis) and the removal of damaged mitochondria by selective autophagy (mitophagy). While mitochondrial function, dynamics, biogenesis and mitophagy are highly-integrated processes, it is not fully understood how systemic control in the cell is established to maintain homeostasis, or respond to bioenergetic demands. Here we used agent-based modeling (ABM) to integrate molecular and imaging knowledge sets, and simulate population dynamics of mitochondria and their response to environmental energy demand. Using high-dimensional parameter searches we integrated experimentally-measured rates of mitochondrial biogenesis and mitophagy, and using sensitivity analysis we identified parameter influences on population homeostasis. By studying the dynamics of cellular subpopulations with distinct mitochondrial masses, our approach uncovered system properties of mitochondrial populations: (1) mitochondrial fusion and fission activities rapidly establish mitochondrial sub-population homeostasis, and total cellular levels of mitochondria alter fusion and fission activities and subpopulation distributions; (2) restricting the directionality of mitochondrial mobility does not alter morphology subpopulation distributions, but increases network transmission dynamics; and (3) maintaining mitochondrial mass homeostasis and responding to bioenergetic stress requires the integration of mitochondrial dynamics with the cellular bioenergetic state. Finally, (4) our model suggests sources of, and stress conditions amplifying

  6. Agent-Based Modeling of Mitochondria Links Sub-Cellular Dynamics to Cellular Homeostasis and Heterogeneity

    PubMed Central

    Dalmasso, Giovanni; Marin Zapata, Paula Andrea; Brady, Nathan Ryan; Hamacher-Brady, Anne

    2017-01-01

    Mitochondria are semi-autonomous organelles that supply energy for cellular biochemistry through oxidative phosphorylation. Within a cell, hundreds of mobile mitochondria undergo fusion and fission events to form a dynamic network. These morphological and mobility dynamics are essential for maintaining mitochondrial functional homeostasis, and alterations both impact and reflect cellular stress states. Mitochondrial homeostasis is further dependent on production (biogenesis) and the removal of damaged mitochondria by selective autophagy (mitophagy). While mitochondrial function, dynamics, biogenesis and mitophagy are highly-integrated processes, it is not fully understood how systemic control in the cell is established to maintain homeostasis, or respond to bioenergetic demands. Here we used agent-based modeling (ABM) to integrate molecular and imaging knowledge sets, and simulate population dynamics of mitochondria and their response to environmental energy demand. Using high-dimensional parameter searches we integrated experimentally-measured rates of mitochondrial biogenesis and mitophagy, and using sensitivity analysis we identified parameter influences on population homeostasis. By studying the dynamics of cellular subpopulations with distinct mitochondrial masses, our approach uncovered system properties of mitochondrial populations: (1) mitochondrial fusion and fission activities rapidly establish mitochondrial sub-population homeostasis, and total cellular levels of mitochondria alter fusion and fission activities and subpopulation distributions; (2) restricting the directionality of mitochondrial mobility does not alter morphology subpopulation distributions, but increases network transmission dynamics; and (3) maintaining mitochondrial mass homeostasis and responding to bioenergetic stress requires the integration of mitochondrial dynamics with the cellular bioenergetic state. Finally, (4) our model suggests sources of, and stress conditions amplifying

  7. Predictability in cellular automata.

    PubMed

    Agapie, Alexandru; Andreica, Anca; Chira, Camelia; Giuclea, Marius

    2014-01-01

    Modelled as finite homogeneous Markov chains, probabilistic cellular automata with local transition probabilities in (0, 1) always posses a stationary distribution. This result alone is not very helpful when it comes to predicting the final configuration; one needs also a formula connecting the probabilities in the stationary distribution to some intrinsic feature of the lattice configuration. Previous results on the asynchronous cellular automata have showed that such feature really exists. It is the number of zero-one borders within the automaton's binary configuration. An exponential formula in the number of zero-one borders has been proved for the 1-D, 2-D and 3-D asynchronous automata with neighborhood three, five and seven, respectively. We perform computer experiments on a synchronous cellular automaton to check whether the empirical distribution obeys also that theoretical formula. The numerical results indicate a perfect fit for neighbourhood three and five, which opens the way for a rigorous proof of the formula in this new, synchronous case.

  8. The Effect of the Number of Simulations on the Exponents Obtained by Finite-Size Scaling Relations of the Order Parameter and the Magnetic Susceptibility for the Four-Dimensional Ising Model on the Creutz Cellular Automaton

    NASA Astrophysics Data System (ADS)

    Merdan, Z.; Güzelsoy, E.

    2012-05-01

    The four-dimensional Ising model is simulated on the Creutz cellular automaton using finite-size lattices with linear dimension 4≤ L≤8. The exponents in the finite-size scaling relations for the order parameter and the magnetic susceptibility at the finite-lattice critical temperature are computed to be β=0.49(7), β=0.49(5), β=0.50(1) and γ=1.04(4), γ=1.03(4), γ=1.02(4) for 7, 14, and 21 independent simulations, respectively. As the number of independent simulations increases, the obtained results are consistent with the renormalization group predictions of β=0.5 and γ=1. The values for the critical temperature of the infinite lattice T c (∞)=6.6788(65), T c (∞)=6.6798(69), T c (∞)=6.6802(70) are obtained from the straight-line fit of the magnetic susceptibility maxima using 4≤ L≤8 for 7, 14, and 21 independent simulations, respectively. As the number of independent simulations increases, the obtained results are in very good agreement with the series expansion results of T c (∞)=6.6817(15), T c (∞)=6.6802(2), the dynamic Monte Carlo result of T c (∞)=6.6803(1), the cluster Monte Carlo result of T c (∞)=6.680(1) and the Monte Carlo using Metropolis and Wolff-cluster algorithm result of T c (∞)=6.6802632±5×10-5.

  9. Microfluidic Electroporation for Cellular Analysis and Delivery

    PubMed Central

    Geng, Tao

    2013-01-01

    Electroporation is a simple yet powerful technique for breaching cell membrane barrier. The applications of electroporation can be generally divided into two categories: the release of intracellular proteins, nucleic acids and other metabolites for analysis and the delivery of exogenous reagents such as genes, drugs and nanoparticles with therapeutic purposes or for cellular manipulation. In this review, we go over the basic physics associated with cell electroporation and highlight recent technological advances on microfluidic platforms for conducting electroporation. Within the context of its working mechanism, we summarize the accumulated knowledge on how the parameters of electroporation affect its performance for various tasks. We discuss various strategies and designs for conducting electroporation at microscale and then focus on analysis of intracellular contents and delivery of exogenous agents as two major applications of the technique. Finally, an outlook for future applications of microfluidic electroporation in increasingly diverse utilities is presented. PMID:23917998

  10. Patient Protection and Affordable Care Act; HHS Notice of Benefit and Payment Parameters for 2018; Amendments to Special Enrollment Periods and the Consumer Operated and Oriented Plan Program. Final rule.

    PubMed

    2016-12-22

    This final rule sets forth payment parameters and provisions related to the risk adjustment program; cost-sharing parameters and cost-sharing reductions; and user fees for Federally-facilitated Exchanges and State-based Exchanges on the Federal platform. It also provides additional guidance relating to standardized options; qualified health plans; consumer assistance tools; network adequacy; the Small Business Health Options Programs; stand-alone dental plans; fair health insurance premiums; guaranteed availability and guaranteed renewability; the medical loss ratio program; eligibility and enrollment; appeals; consumer-operated and oriented plans; special enrollment periods; and other related topics.

  11. Cellular automaton for chimera states

    NASA Astrophysics Data System (ADS)

    García-Morales, Vladimir

    2016-04-01

    A minimalistic model for chimera states is presented. The model is a cellular automaton (CA) which depends on only one adjustable parameter, the range of the nonlocal coupling, and is built from elementary cellular automata and the majority (voting) rule. This suggests the universality of chimera-like behavior from a new point of view: Already simple CA rules based on the majority rule exhibit this behavior. After a short transient, we find chimera states for arbitrary initial conditions, the system spontaneously splitting into stable domains separated by static boundaries, some synchronously oscillating and the others incoherent. When the coupling range is local, nontrivial coherent structures with different periodicities are formed.

  12. Continuum representations of cellular solids

    NASA Astrophysics Data System (ADS)

    Neilsen, M. K.

    1993-09-01

    Cellular materials consist of interconnected struts or plates which form cells. The struts or plates are constructed from a variety of metals, polymers, ceramics, and wood products. Cellular materials are often used in impact limiters for shipping containers to protect the contents from accidental impact events. These materials exhibit a variety of complex behavior when subjected to crushing loads. This research focuses on the development of continuum representations of cellular solids that can be used in the finite element analysis of shipping container accidents. A significant portion of this work is the development of a new methodology to relate localized deformations to appropriate constitutive descriptions. This methodology provides the insight needed to select constitutive descriptions for cellular solids that capture the localized deformations that are observed experimentally. Constitutive relations are developed for two different cellular materials, aluminum honeycomb and polyurethane foam. These constitutive relations are based on plasticity and continuum damage theories. Plasticity is used to describe the permanent deformation exhibited by both aluminum honeycomb and polyurethane foam. Continuum damage is needed to capture the change in elastic parameters due to cracking of the polyurethane cell wall materials. The new constitutive description of polyurethane foam is implemented in both static and dynamic finite element codes, and analytical and numerical predictions are compared with available experimental data.

  13. Continuum representations of cellular solids

    SciTech Connect

    Neilsen, M.K.

    1993-09-01

    Cellular materials consist of interconnected struts or plates which form cells. The struts or plates are constructed from a variety of metals, polymers, ceramics and wood products. Cellular materials are often used in impact limiters for shipping containers to protect the contents from accidental impact events. These materials exhibit a variety of complex behavior when subjected to crushing loads. This research focuses on the development of continuum representations of cellular solids that can be used in the finite element analysis of shipping container accidents. A significant portion of this work is the development of a new methodology to relate localized deformations to appropriate constitutive descriptions. This methodology provides the insight needed to select constitutive descriptions for cellular solids that capture the localized deformations that are observed experimentally. Constitutive relations are developed for two different cellular materials, aluminum honeycomb and polyurethane foam. These constitutive relations are based on plasticity and continuum damage theories. Plasticity is used to describe the permanent deformation exhibited by both aluminum honeycomb and polyurethane foam. Continuum damage is needed to capture the change in elastic parameters due to cracking of the polyurethane cell wall materials. The new constitutive description of polyurethane foam is implemented in both static and dynamic finite element codes, and analytical and numerical predictions are compared with available experimental data.

  14. Hierarchical cellular materials

    SciTech Connect

    Gibson, L.J.

    1991-12-31

    In this paper a method for estimating the contributions of both the composite and the cellular microstructures to the overall material properties and the mechanical efficiency of natural cellular solids will be described. The method will be demonstrated by focusing on the Young`s modulus; similar techniques can be used for other material properties. The results suggest efficient microstructures for engineered cellular materials.

  15. Hierarchical cellular materials

    SciTech Connect

    Gibson, L.J.

    1991-01-01

    In this paper a method for estimating the contributions of both the composite and the cellular microstructures to the overall material properties and the mechanical efficiency of natural cellular solids will be described. The method will be demonstrated by focusing on the Young's modulus; similar techniques can be used for other material properties. The results suggest efficient microstructures for engineered cellular materials.

  16. Final report on the study of the effect of primary and secondary plant parameters on light-water-reactor transient behavior. Progress report, July 1-December 31, 1982

    SciTech Connect

    Baratta, A.J.; Robinson, G.E.; Kim, D.; Brownson, D.A.; Morales, J.B.; Huegel, D.; Gul, M.; Macario, F.

    1983-04-01

    Since the Three Mile Island Accident of March 1979, various approaches have been undertaken to reduce the probability of such occurrences. In general, these involve the addition of more complex and sophisticated engineered safety systems and instrumentation and control systems. Such improvements will undoubtedly improve overall plant safety. This project explores an alternative approach - the optimization of the transient behavior of the reactor and associated systems. Specifically, the ability of B and W and Westinghouse reactor to withstand a turbine trip was investigated. The project examined whether the plant's transient behavior with respect to peak reactor coolant system (RCS) behavior could be optimized. Several key parameters including pressurizer size, surge line impedence, time to SCRAM, and fuel and moderator temperature coefficients were varied. It was found that increasing pressurizer size decreased peak RCS pressure.

  17. Cellular Mechanisms of Transcranial Direct Current Stimulation

    DTIC Science & Technology

    2016-07-14

    AFRL-AFOSR-VA-TR-2016-0252 Cellular Mechanisms of Transcranial Direct Current Stimulation Marom Bikson RFCUNY - CITY COLLEGE CONVENT AVE & 138TH ST...2. REPORT TYPE Final 3. DATES COVERED (From - To) March 15, 2013 to March 14, 2016 4. TITLE AND SUBTITLE Cellular Mechanisms of Transcranial Direct ...ACRONYM(S) 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT 13. SUPPLEMENTARY NOTES 14. ABSTRACT During transcranial Direct

  18. Fibre based cellular transfection.

    PubMed

    Tsampoula, X; Taguchi, K; Cizmár, T; Garces-Chavez, V; Ma, N; Mohanty, S; Mohanty, K; Gunn-Moore, F; Dholakia, K

    2008-10-13

    Optically assisted transfection is emerging as a powerful and versatile method for the delivery of foreign therapeutic agents to cells at will. In particular the use of ultrashort pulse lasers has proved an important route to transiently permeating the cell membrane through a multiphoton process. Though optical transfection has been gaining wider usage to date, all incarnations of this technique have employed free space light beams. In this paper we demonstrate the first system to use fibre delivery for the optical transfection of cells. We engineer a standard optical fibre to generate an axicon tip with an enhanced intensity of the remote output field that delivers ultrashort (~ 800 fs) pulses without requiring the fibre to be placed in very close proximity to the cell sample. A theoretical model is also developed in order to predict the light propagation from axicon tipped and bare fibres, in both air and water environments. The model proves to be in good agreement with the experimental findings and can be used to establish the optimum fibre parameters for successful cellular transfection. We readily obtain efficiencies of up to 57 % which are comparable with free space transfection. This advance paves the way for optical transfection of tissue samples and endoscopic embodiments of this technique.

  19. A Cellular Biophysics Textbook

    NASA Astrophysics Data System (ADS)

    Wilder, Alan Joseph

    2011-12-01

    In the past two decades, great advances have been made in understanding of the biophysical mechanisms of the protein machines that carry out the fundamental processes of the cell. It is now known that all major eukaryotic cellular processes require a complicated assemblage of proteins acting via a series of concerted motions. In order to grasp current understanding of cellular mechanisms, the new generation of cell biologists needs to be trained in the general characteristics of these cellular properties and the methods with which to study them. This cellular biophysics textbook, to be used in conjunction with the cellular biophysics course (MCB143) at UC-Davis, provides a great tool in the instruction of the new generation of cellular biologists. It provides a hierarchical view of the cell, from atoms to protein machines and explains in depth the mechanisms of cytoskeletal force generators as an example of these principles.

  20. Effects of electromagnetic field stimulation on cellular signal transduction mechanisms: Analyses of the effects of low frequency electromagnetic fields on calcium spiking in ROS 17/2.8 cells. Final report

    SciTech Connect

    Sisken, B.F.; Sisken, J.E.

    1997-12-01

    The general goals of this work were to determine whether resting levels of cellular second messengers, especially calcium, are affected by low-level electromagnetic fields and the mechanisms that could lead to such changes. The work performed was directed at (1) verifying the report of McLeod et al (1990) that low frequency sinusoidal EMF can alter basal calcium fluctuations in cultured ROS 17/2.8 osteoblast-like cells and (2) reproducing the findings of Luben et al (1982) that pulsed electromagnetic fields can affect PTH-stimulated adenylate cyclase activity in osteoblasts. Initially a system was constructed so that cells could be exposed to sinusoidal electric fields using platinum electrodes. In this system, the electrodes were separated from the cells and culture medium by agar barriers. A series of experiments indicated that this system was subject to a significant, though little-known artifact in which a not well understood interaction between the electrodes and sodium ions in the medium or in plain salt solutions led to frequency and amplitude dependent emission of photons that are recorded by the detection system. They therefore designed and constructed an air gap reactor system that utilizes a ferromagnetic core to direct the magnetic flux generated by a sinusoidal coil. Studies on the effects of a 15 Hz pulsed electromagnetic field (PEMF) on cyclic AMP metabolism were performed on ROS 17/2.8 and MC3T3 cells.

  1. Stochastic extension of cellular manufacturing systems: a queuing-based analysis

    NASA Astrophysics Data System (ADS)

    Fardis, Fatemeh; Zandi, Afagh; Ghezavati, Vahidreza

    2013-07-01

    Clustering parts and machines into part families and machine cells is a major decision in the design of cellular manufacturing systems which is defined as cell formation. This paper presents a non-linear mixed integer programming model to design cellular manufacturing systems which assumes that the arrival rate of parts into cells and machine service rate are stochastic parameters and described by exponential distribution. Uncertain situations may create a queue behind each machine; therefore, we will consider the average waiting time of parts behind each machine in order to have an efficient system. The objective function will minimize summation of idleness cost of machines, sub-contracting cost for exceptional parts, non-utilizing machine cost, and holding cost of parts in the cells. Finally, the linearized model will be solved by the Cplex solver of GAMS, and sensitivity analysis will be performed to illustrate the effectiveness of the parameters.

  2. Plasmonic Nanostructured Cellular Automata

    NASA Astrophysics Data System (ADS)

    Alkhazraji, Emad; Ghalib, A.; Manzoor, K.; Alsunaidi, M. A.

    2017-03-01

    In this work, we have investigated the scattering plasmonic resonance characteristics of silver nanospheres with a geometrical distribution that is modelled by Cellular Automata using time-domain numerical analysis. Cellular Automata are discrete mathematical structures that model different natural phenomena. Two binary one-dimensional Cellular Automata rules are considered to model the nanostructure, namely rule 30 and rule 33. The analysis produces three-dimensional scattering profiles of the entire plasmonic nanostructure. For the Cellular Automaton rule 33, the introduction of more Cellular Automata generations resulted only in slight red and blue shifts in the plasmonic modes with respect to the first generation. On the other hand, while rule 30 introduced significant red shifts in the resonance peaks at early generations, at later generations however, a peculiar effect is witnessed in the scattering profile as new peaks emerge as a feature of the overall Cellular Automata structure rather than the sum of the smaller parts that compose it. We strongly believe that these features that emerge as a result adopting the different 256 Cellular Automata rules as configuration models of nanostructures in different applications and systems might possess a great potential in enhancing their capability, sensitivity, efficiency, and power utilization.

  3. Cellular Reflectarray Antenna

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R.

    2010-01-01

    The cellular reflectarray antenna is intended to replace conventional parabolic reflectors that must be physically aligned with a particular satellite in geostationary orbit. These arrays are designed for specified geographical locations, defined by latitude and longitude, each called a "cell." A particular cell occupies nominally 1,500 square miles (3,885 sq. km), but this varies according to latitude and longitude. The cellular reflectarray antenna designed for a particular cell is simply positioned to align with magnetic North, and the antenna surface is level (parallel to the ground). A given cellular reflectarray antenna will not operate in any other cell.

  4. Cellular aging and cancer

    PubMed Central

    Hornsby, Peter J.

    2010-01-01

    Aging is manifest in a variety of changes over time, including changes at the cellular level. Cellular aging acts primarily as a tumor suppressor mechanism, but also may enhance cancer development under certain circumstances. One important process of cellular aging is oncogene-induced senescence, which acts as an important anti-cancer mechanism. Cellular senescence resulting from damage caused by activated oncogenes prevents the growth or potentially neoplastic cells. Moreover, cells that have entered senescence appear to be targets for elimination by the innnate immune system. In another aspect of cellular aging, the absence of telomerase activity in normal tissues results in such cells lacking a telomere maintenance mechanism. One consequence is that in aging there is an increase in cells with shortened telomeres. In the presence of active oncogenes that cause expansion of a neoplastic clone, shortening of telomeres leading to telomere dysfunction prevents the indefinite expansion of the clone because the cells enter crisis. Crisis results from fusions and other defects caused by dysfunctional telomeres and is a terminal state of the neoplastic clone. In this way the absence of telomerase in human cells, while one cause of cellular aging, also acts as an anti-cancer mechanism. PMID:20705476

  5. Cellular immune response experiment MA-031

    NASA Technical Reports Server (NTRS)

    Criswell, B. S.

    1976-01-01

    Significant changes in phytohemagglutinin (PHA) lymphocytic responsiveness occurred in the cellular immune response of three astronauts during the 9 day flight of the Apollo Soyuz Test Project. Parameters studied were white blood cell concentrations, lymphocyte numbers, B- and T-lymphocyte distributions in peripheral blood, and lymphocyte responsiveness to PHA, pokeweed mitogen, Concanavalin A, and influenza virus antigen.

  6. Passive drug permeation through membranes and cellular distribution.

    PubMed

    Scott, D O; Ghosh, A; Di, L; Maurer, T S

    2017-03-01

    Although often overlooked, passive mechanisms can lead to significant accumulation or restriction of drugs to intracellular sites of drug action. These mechanisms include lipoidal diffusion of ionized species and pH partitioning according to the electrochemical potential and to pH gradients that exist across subcellular compartments, respectively. These mechanisms are increasingly being exploited in the design of safe and effective drugs for the treatment of a wide variety of diseases. In this work, the authors review these efforts and the associated passive mechanisms of cellular drug permeation. A generic mathematical model of the cell is provided and used to illustrate concepts relevant to steady-state intracellular distribution. Finally, the authors review methods for estimating determinant parameters and measuring the net effect at the level of unbound intracellular drug concentrations.

  7. 77 FR 1889 - Drivers of CMVs: Restricting the Use of Cellular Phones; Technical Amendment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-12

    ... Use of Cellular Phones; Technical Amendment AGENCY: Federal Motor Carrier Safety Administration (FMCSA... the Use of Cellular Phones final rule (76 FR 75470) had a clerical error in Sec. 391.15(f)(1)...

  8. Irregular Cellular Learning Automata.

    PubMed

    Esnaashari, Mehdi; Meybodi, Mohammad Reza

    2015-08-01

    Cellular learning automaton (CLA) is a recently introduced model that combines cellular automaton (CA) and learning automaton (LA). The basic idea of CLA is to use LA to adjust the state transition probability of stochastic CA. This model has been used to solve problems in areas such as channel assignment in cellular networks, call admission control, image processing, and very large scale integration placement. In this paper, an extension of CLA called irregular CLA (ICLA) is introduced. This extension is obtained by removing the structure regularity assumption in CLA. Irregularity in the structure of ICLA is needed in some applications, such as computer networks, web mining, and grid computing. The concept of expediency has been introduced for ICLA and then, conditions under which an ICLA becomes expedient are analytically found.

  9. Epigenetics and Cellular Metabolism

    PubMed Central

    Xu, Wenyi; Wang, Fengzhong; Yu, Zhongsheng; Xin, Fengjiao

    2016-01-01

    Living eukaryotic systems evolve delicate cellular mechanisms for responding to various environmental signals. Among them, epigenetic machinery (DNA methylation, histone modifications, microRNAs, etc.) is the hub in transducing external stimuli into transcriptional response. Emerging evidence reveals the concept that epigenetic signatures are essential for the proper maintenance of cellular metabolism. On the other hand, the metabolite, a main environmental input, can also influence the processing of epigenetic memory. Here, we summarize the recent research progress in the epigenetic regulation of cellular metabolism and discuss how the dysfunction of epigenetic machineries influences the development of metabolic disorders such as diabetes and obesity; then, we focus on discussing the notion that manipulating metabolites, the fuel of cell metabolism, can function as a strategy for interfering epigenetic machinery and its related disease progression as well. PMID:27695375

  10. Origins of cellular geometry

    PubMed Central

    2011-01-01

    Cells are highly complex and orderly machines, with defined shapes and a startling variety of internal organizations. Complex geometry is a feature of both free-living unicellular organisms and cells inside multicellular animals. Where does the geometry of a cell come from? Many of the same questions that arise in developmental biology can also be asked of cells, but in most cases we do not know the answers. How much of cellular organization is dictated by global cell polarity cues as opposed to local interactions between cellular components? Does cellular structure persist across cell generations? What is the relationship between cell geometry and tissue organization? What ensures that intracellular structures are scaled to the overall size of the cell? Cell biology is only now beginning to come to grips with these questions. PMID:21880160

  11. Measuring information flow in cellular networks by the systems biology method through microarray data.

    PubMed

    Chen, Bor-Sen; Li, Cheng-Wei

    2015-01-01

    In general, it is very difficult to measure the information flow in a cellular network directly. In this study, based on an information flow model and microarray data, we measured the information flow in cellular networks indirectly by using a systems biology method. First, we used a recursive least square parameter estimation algorithm to identify the system parameters of coupling signal transduction pathways and the cellular gene regulatory network (GRN). Then, based on the identified parameters and systems theory, we estimated the signal transductivities of the coupling signal transduction pathways from the extracellular signals to each downstream protein and the information transductivities of the GRN between transcription factors in response to environmental events. According to the proposed method, the information flow, which is characterized by signal transductivity in coupling signaling pathways and information transductivity in the GRN, can be estimated by microarray temporal data or microarray sample data. It can also be estimated by other high-throughput data such as next-generation sequencing or proteomic data. Finally, the information flows of the signal transduction pathways and the GRN in leukemia cancer cells and non-leukemia normal cells were also measured to analyze the systematic dysfunction in this cancer from microarray sample data. The results show that the signal transductivities of signal transduction pathways change substantially from normal cells to leukemia cancer cells.

  12. Measuring information flow in cellular networks by the systems biology method through microarray data

    PubMed Central

    Chen, Bor-Sen; Li, Cheng-Wei

    2015-01-01

    In general, it is very difficult to measure the information flow in a cellular network directly. In this study, based on an information flow model and microarray data, we measured the information flow in cellular networks indirectly by using a systems biology method. First, we used a recursive least square parameter estimation algorithm to identify the system parameters of coupling signal transduction pathways and the cellular gene regulatory network (GRN). Then, based on the identified parameters and systems theory, we estimated the signal transductivities of the coupling signal transduction pathways from the extracellular signals to each downstream protein and the information transductivities of the GRN between transcription factors in response to environmental events. According to the proposed method, the information flow, which is characterized by signal transductivity in coupling signaling pathways and information transductivity in the GRN, can be estimated by microarray temporal data or microarray sample data. It can also be estimated by other high-throughput data such as next-generation sequencing or proteomic data. Finally, the information flows of the signal transduction pathways and the GRN in leukemia cancer cells and non-leukemia normal cells were also measured to analyze the systematic dysfunction in this cancer from microarray sample data. The results show that the signal transductivities of signal transduction pathways change substantially from normal cells to leukemia cancer cells. PMID:26082788

  13. The New Cellular Immunology

    ERIC Educational Resources Information Center

    Claman, Henry N.

    1973-01-01

    Discusses the nature of the immune response and traces many of the discoveries that have led to the present state of knowledge in immunology. The new cellular immunology is directing its efforts toward improving health by proper manipulation of the immune mechanisms of the body. (JR)

  14. Cellular genetic therapy.

    PubMed

    Del Vecchio, F; Filareto, A; Spitalieri, P; Sangiuolo, F; Novelli, G

    2005-01-01

    Cellular genetic therapy is the ultimate frontier for those pathologies that are consequent to a specific nonfunctional cellular type. A viable cure for there kinds of diseases is the replacement of sick cells with healthy ones, which can be obtained from the same patient or a different donor. In fact, structures can be corrected and strengthened with the introduction of undifferentiated cells within specific target tissues, where they will specialize into the desired cellular types. Furthermore, consequent to the recent results obtained with the transdifferentiation experiments, a process that allows the in vitro differentiation of embryonic and adult stem cells, it has also became clear that many advantages may be obtained from the use of stem cells to produce drugs, vaccines, and therapeutic molecules. Since stem cells can sustain lineage potentials, the capacity for differentiation, and better tolerance for the introduction of exogenous genes, they are also considered as feasible therapeutic vehicles for gene therapy. In fact, it is strongly believed that the combination of cellular genetic and gene therapy approaches will definitely allow the development of new therapeutic strategies as well as the production of totipotent cell lines to be used as experimental models for the cure of genetic disorders.

  15. Genetic Dominance & Cellular Processes

    ERIC Educational Resources Information Center

    Seager, Robert D.

    2014-01-01

    In learning genetics, many students misunderstand and misinterpret what "dominance" means. Understanding is easier if students realize that dominance is not a mechanism, but rather a consequence of underlying cellular processes. For example, metabolic pathways are often little affected by changes in enzyme concentration. This means that…

  16. Detonation cellular structure and image proces

    NASA Astrophysics Data System (ADS)

    Shepherd, J. E.; Tieszen, S. R.

    Gaseous detonations universally exhibit an instability that is manifested as cellular patterns on witness plates (sooted foils) or open shutter photographs. The characteristic dimension or cell width lambda of the periodic cellular pattern has previously been shown to correlate with failure diameter, critical diffraction aperture dimension and direct initiation energy requirements. Due to the importance of predicting these parameters in assessing detonability hazards, a quantitative method for cell size mesurement is urgently needed. We discuss a technique based on digital image processing of sooted foil records and illustrate the results with data from experiments performed in the Heated Detonation Tube facility at Sandia. We demonstrate that image processing can be used to eliminate some of the uncertainty now present in cell size measurements. The possibility of quantifying cellular irregularity is also explored.

  17. Probabilistic cellular automata.

    PubMed

    Agapie, Alexandru; Andreica, Anca; Giuclea, Marius

    2014-09-01

    Cellular automata are binary lattices used for modeling complex dynamical systems. The automaton evolves iteratively from one configuration to another, using some local transition rule based on the number of ones in the neighborhood of each cell. With respect to the number of cells allowed to change per iteration, we speak of either synchronous or asynchronous automata. If randomness is involved to some degree in the transition rule, we speak of probabilistic automata, otherwise they are called deterministic. With either type of cellular automaton we are dealing with, the main theoretical challenge stays the same: starting from an arbitrary initial configuration, predict (with highest accuracy) the end configuration. If the automaton is deterministic, the outcome simplifies to one of two configurations, all zeros or all ones. If the automaton is probabilistic, the whole process is modeled by a finite homogeneous Markov chain, and the outcome is the corresponding stationary distribution. Based on our previous results for the asynchronous case-connecting the probability of a configuration in the stationary distribution to its number of zero-one borders-the article offers both numerical and theoretical insight into the long-term behavior of synchronous cellular automata.

  18. Formin’ cellular structures

    PubMed Central

    Bogdan, Sven; Schultz, Jörg; Grosshans, Jörg

    2014-01-01

    Members of the Diaphanous (Dia) protein family are key regulators of fundamental actin driven cellular processes, which are conserved from yeast to humans. Researchers have uncovered diverse physiological roles in cell morphology, cell motility, cell polarity, and cell division, which are involved in shaping cells into tissues and organs. The identification of numerous binding partners led to substantial progress in our understanding of the differential functions of Dia proteins. Genetic approaches and new microscopy techniques allow important new insights into their localization, activity, and molecular principles of regulation. PMID:24719676

  19. Cellular mechanics and motility

    NASA Astrophysics Data System (ADS)

    Hénon, Sylvie; Sykes, Cécile

    2015-10-01

    The term motility defines the movement of a living organism. One widely known example is the motility of sperm cells, or the one of flagellar bacteria. The propulsive element of such organisms is a cilium(or flagellum) that beats. Although cells in our tissues do not have a flagellum in general, they are still able to move, as we will discover in this chapter. In fact, in both cases of movement, with or without a flagellum, cell motility is due to a dynamic re-arrangement of polymers inside the cell. Let us first have a closer look at the propulsion mechanism in the case of a flagellum or a cilium, which is the best known, but also the simplest, and which will help us to define the hydrodynamic general conditions of cell movement. A flagellum is sustained by cellular polymers arranged in semi-flexible bundles and flagellar beating generates cell displacement. These polymers or filaments are part of the cellular skeleton, or "cytoskeleton", which is, in this case, external to the cellular main body of the organism. In fact, bacteria move in a hydrodynamic regime in which viscosity dominates over inertia. The system is thus in a hydrodynamic regime of low Reynolds number (Box 5.1), which is nearly exclusively the case in all cell movements. Bacteria and their propulsion mode by flagella beating are our unicellular ancestors 3.5 billion years ago. Since then, we have evolved to form pluricellular organisms. However, to keep the ability of displacement, to heal our wounds for example, our cells lost their flagellum, since it was not optimal in a dense cell environment: cells are too close to each other to leave enough space for the flagella to accomplish propulsion. The cytoskeleton thus developed inside the cell body to ensure cell shape changes and movement, and also mechanical strength within a tissue. The cytoskeleton of our cells, like the polymers or filaments that sustain the flagellum, is also composed of semi-flexible filaments arranged in bundles, and also in

  20. Oral Cellular Neurothekeoma

    PubMed Central

    Emami, Nader; Zawawi, Faisal; Ywakim, Rania; Daniel, Sam J.

    2013-01-01

    Cellular neurothekeoma is known as a cutaneous tumor with uncertain histogenesis. Very little involvement of mucosal membrane has been reported in the literature so far. This is a case report of an intraoral lesion in a 15-years-old girl. Histopathologic evaluation showed a tumor-consists of spindle to epitheloid cells forming micronodules in a concentric whorled shape pattern. Tumor cells were positive for CD63, vimentin, and NKI-C3. Total excision was performed and no recurrence happened after 16-month followup. PMID:23691398

  1. Solid films and transports in cellular foams

    NASA Astrophysics Data System (ADS)

    Tan Hoang, Minh; Perrot, Camille

    2012-09-01

    We show that critical path ideas lead to the identification of two local characteristic sizes for the long wavelength acoustic properties in cellular solids, the pore and throat sizes. Application of the model to real foam samples, which may contain solid films or membranes yields quantitative agreement between a finite-element numerical homogenization approach and experimental results. From three routinely available laboratory measurements: the open porosity ϕ, the static viscous permeability k0, and the average struts length Lm obtained from microscopy analysis; asymptotic transport parameters at high-frequencies and the normal incidence sound absorption coefficient are derived with no adjustable parameters.

  2. Revisiting Cardiac Cellular Composition

    PubMed Central

    Pinto, Alexander R.; Ilinykh, Alexei; Ivey, Malina J.; Kuwabara, Jill T.; D'Antoni, Michelle L.; Debuque, Ryan; Chandran, Anjana; Wang, Lina; Arora, Komal; Rosenthal, Nadia; Tallquist, Michelle D.

    2015-01-01

    Rationale Accurate knowledge of the cellular composition of the heart is essential to fully understand the changes that occur during pathogenesis and to devise strategies for tissue engineering and regeneration. Objective To examine the relative frequency of cardiac endothelial cells, hematopoietic-derived cells and fibroblasts in the mouse and human heart. Methods and Results Using a combination of genetic tools and cellular markers, we examined the occurrence of the most prominent cell types in the adult mouse heart. Immunohistochemistry revealed that endothelial cells constitute over 60%, hematopoietic-derived cells 5–10%, and fibroblasts under 20% of the non-myocytes in the heart. A refined cell isolation protocol and an improved flow cytometry approach provided an independent means of determining the relative abundance of non-myocytes. High dimensional analysis and unsupervised clustering of cell populations confirmed that endothelial cells are the most abundant cell population. Interestingly, fibroblast numbers are smaller than previously estimated, and two commonly assigned fibroblast markers, Sca-1 and CD90, underrepresent fibroblast numbers. We also describe an alternative fibroblast surface marker that more accurately identifies the resident cardiac fibroblast population. Conclusions This new perspective on the abundance of different cell types in the heart demonstrates that fibroblasts comprise a relatively minor population. By contrast, endothelial cells constitute the majority of non-cardiomyocytes and are likely to play a greater role in physiologic function and response to injury than previously appreciated. PMID:26635390

  3. Multifunctional periodic cellular metals.

    PubMed

    Wadley, Haydn N G

    2006-01-15

    Periodic cellular metals with honeycomb and corrugated topologies are widely used for the cores of light weight sandwich panel structures. Honeycombs have closed cell pores and are well suited for thermal protection while also providing efficient load support. Corrugated core structures provide less efficient and highly anisotropic load support, but enable cross flow heat exchange opportunities because their pores are continuous in one direction. Recent advances in topology design and fabrication have led to the emergence of lattice truss structures with open cell structures. These three classes of periodic cellular metals can now be fabricated from a wide variety of structural alloys. Many topologies are found to provide adequate stiffness and strength for structural load support when configured as the cores of sandwich panels. Sandwich panels with core relative densities of 2-10% and cell sizes in the millimetre range are being assessed for use as multifunctional structures. The open, three-dimensional interconnected pore networks of lattice truss topologies provide opportunities for simultaneously supporting high stresses while also enabling cross flow heat exchange. These highly compressible structures also provide opportunities for the mitigation of high intensity dynamic loads created by impacts and shock waves in air or water. By filling the voids with polymers and hard ceramics, these structures have also been found to offer significant resistance to penetration by projectiles.

  4. Cellular Array Processing Simulation

    NASA Astrophysics Data System (ADS)

    Lee, Harry C.; Preston, Earl W.

    1981-11-01

    The Cellular Array Processing Simulation (CAPS) system is a high-level image language that runs on a multiprocessor configuration. CAPS is interpretively decoded on a conventional minicomputer with all image operation instructions executed on an array processor. The synergistic environment that exists between the minicomputer and the array processor gives CAPS its high-speed throughput, while maintaining a convenient conversational user language. CAPS was designed to be both modular and table driven so that it can be easily maintained and modified. CAPS uses the image convolution operator as one of its primitives and performs this cellular operation by decomposing it into parallel image steps that are scheduled to be executed on the array processor. Among its features is the ability to observe the imagery in real time as a user's algorithm is executed. This feature reduces the need for image storage space, since it is feasible to retain only original images and produce resultant images when needed. CAPS also contains a language processor that permits users to develop re-entrant image processing subroutines or algorithms.

  5. To study the effects of gamma irradiation on single donor apheresis platelet units by measurement of cellular counts, functional indicators and a panel of biochemical parameters, in order to assess pre-transfusion platelet quantity and quality during the shelf life of the product

    PubMed Central

    Mallhi, R.S.; Biswas, A.K.; Philip, J.; Chatterjee, T.

    2016-01-01

    Background The occurrence of transfusion associated graft versus host disease can be prevented by gamma irradiation of blood components. This study was undertaken to assess the effects of gamma irradiation on single donor platelet (SDP) concentrate units. Method SDPs were collected by a continuous flow apheresis technique (n = 400). The SDPs from each donor were divided into two parts, one gamma-irradiated with 25 Gy and the other used as a non-irradiated control. Swirling and morphological features, cellular counts, biochemical parameters including blood gas analysis, and platelet activation levels (CD62P: p-selectin) by flow cytometry were analyzed on Day 1 and on Day 5. Results Swirling and morphology were maintained in all products, in both the groups throughout the shelf life. No significant change was seen in both groups, on the first and fifth day, as far as pO2, pCO2, Na+, K+, HCO3− & Ca2+ were concerned. However, lactate increased and glucose decreased significantly in irradiated products over 5-day storage period. A small but significant decrease in pH and platelet count was found in the irradiated PCs after 5-day storage. The mean proportion of platelets expressing CD62P over 5-day storage increased significantly. Conclusion After an overall assessment of all our in vitro parameter results and observations, a few of which were significant, while most were not significant, we concluded that a well-preserved quality of gamma irradiated apheresis platelets is maintained throughout the entire 5-day shelf life of the platelet product, with minimal difference compared to non-irradiated platelets. PMID:26900218

  6. Final Report

    SciTech Connect

    Gurney, Kevin R.

    2015-01-12

    This document constitutes the final report under DOE grant DE-FG-08ER64649. The organization of this document is as follows: first, I will review the original scope of the proposed research. Second, I will present the current draft of a paper nearing submission to Nature Climate Change on the initial results of this funded effort. Finally, I will present the last phase of the research under this grant which has supported a Ph.D. student. To that end, I will present the graduate student’s proposed research, a portion of which is completed and reflected in the paper nearing submission. This final work phase will be completed in the next 12 months. This final workphase will likely result in 1-2 additional publications and we consider the results (as exemplified by the current paper) high quality. The continuing results will acknowledge the funding provided by DOE grant DE-FG-08ER64649.

  7. Final Report

    SciTech Connect

    DeTar, Carleton

    2012-12-10

    This document constitutes the Final Report for award DE-FC02-06ER41446 as required by the Office of Science. It summarizes accomplishments and provides copies of scientific publications with significant contribution from this award.

  8. Cellular basis of memory for addiction.

    PubMed

    Nestler, Eric J

    2013-12-01

    DESPITE THE IMPORTANCE OF NUMEROUS PSYCHOSOCIAL FACTORS, AT ITS CORE, DRUG ADDICTION INVOLVES A BIOLOGICAL PROCESS: the ability of repeated exposure to a drug of abuse to induce changes in a vulnerable brain that drive the compulsive seeking and taking of drugs, and loss of control over drug use, that define a state of addiction. Here, we review the types of molecular and cellular adaptations that occur in specific brain regions to mediate addiction-associated behavioral abnormalities. These include alterations in gene expression achieved in part via epigenetic mechanisms, plasticity in the neurophysiological functioning of neurons and synapses, and associated plasticity in neuronal and synaptic morphology mediated in part by altered neurotrophic factor signaling. Each of these types of drug-induced modifications can be viewed as a form of "cellular or molecular memory." Moreover, it is striking that most addiction-related forms of plasticity are very similar to the types of plasticity that have been associated with more classic forms of "behavioral memory," perhaps reflecting the finite repertoire of adaptive mechanisms available to neurons when faced with environmental challenges. Finally, addiction-related molecular and cellular adaptations involve most of the same brain regions that mediate more classic forms of memory, consistent with the view that abnormal memories are important drivers of addiction syndromes. The goal of these studies which aim to explicate the molecular and cellular basis of drug addiction is to eventually develop biologically based diagnostic tests, as well as more effective treatments for addiction disorders.

  9. [Senescence and cellular immortality].

    PubMed

    Trentesaux, C; Riou, J-F

    2010-11-01

    Senescence was originally described from the observation of the limited ability of normal cells to grow in culture, and may be generated by telomere erosion, accumulation of DNA damages, oxidative stress and modulation of oncogenes or tumor suppressor genes. Senescence corresponds to a cellular response aiming to control tumor progression by limiting cell proliferation and thus constitutes an anticancer barrier. Senescence is observed in pre-malignant tumor stages and disappears from malignant tumors. Agents used in standard chemotherapy also have the potential to induce senescence, which may partly explain their therapeutic activities. It is possible to restore senescence in tumors using targeted therapies that triggers telomere dysfunction or reactivates suppressor genes functions, which are essential for the onset of senescence.

  10. Articulatory Parameters.

    ERIC Educational Resources Information Center

    Ladefoged, Peter

    1980-01-01

    Summarizes the 16 parameters hypothesized to be necessary and sufficient for linguistic phonetic specifications. Suggests seven parameters affecting tongue shapes, three determining the positions of the lips, one controlling the position of the velum, four varying laryngeal actions, and one controlling respiratory activity. (RL)

  11. Cellular automaton for bacterial towers

    NASA Astrophysics Data System (ADS)

    Indekeu, J. O.; Giuraniuc, C. V.

    2004-05-01

    A simulation approach to the stochastic growth of bacterial towers is presented, in which a non-uniform and finite nutrient supply essentially determines the emerging structure through elementary chemotaxis. The method is based on cellular automata and we use simple, microscopic, local rules for bacterial division in nutrient-rich surroundings. Stochastic nutrient diffusion, while not crucial to the dynamics of the total population, is influential in determining the porosity of the bacterial tower and the roughness of its surface. As the bacteria run out of food, we observe an exponentially rapid saturation to a carrying capacity distribution, similar in many respects to that found in a recently proposed phenomenological hierarchical population model, which uses heuristic parameters and macroscopic rules. Complementary to that phenomenological model, the simulation aims at giving more microscopic insight into the possible mechanisms for one of the recently much studied bacterial morphotypes, known as “towering biofilm”, observed experimentally using confocal laser microscopy. A simulation suggesting a mechanism for biofilm resistance to antibiotics is also shown.

  12. SELF-ORGANIZED CRITICALITY AND CELLULAR AUTOMATA

    SciTech Connect

    CREUTZ,M.

    2007-01-01

    Cellular automata provide a fascinating class of dynamical systems based on very simple rules of evolution yet capable of displaying highly complex behavior. These include simplified models for many phenomena seen in nature. Among other things, they provide insight into self-organized criticality, wherein dissipative systems naturally drive themselves to a critical state with important phenomena occurring over a wide range of length and the scales. This article begins with an overview of self-organized criticality. This is followed by a discussion of a few examples of simple cellular automaton systems, some of which may exhibit critical behavior. Finally, some of the fascinating exact mathematical properties of the Bak-Tang-Wiesenfeld sand-pile model [1] are discussed.

  13. Active Degradation Explains the Distribution of Nuclear Proteins during Cellular Senescence

    PubMed Central

    Giampieri, Enrico; De Cecco, Marco; Remondini, Daniel; Sedivy, John; Castellani, Gastone

    2015-01-01

    The amount of cellular proteins is a crucial parameter that is known to vary between cells as a function of the replicative passages, and can be important during physiological aging. The process of protein degradation is known to be performed by a series of enzymatic reactions, ranging from an initial step of protein ubiquitination to their final fragmentation by the proteasome. In this paper we propose a stochastic dynamical model of nuclear proteins concentration resulting from a balance between a constant production of proteins and their degradation by a cooperative enzymatic reaction. The predictions of this model are compared with experimental data obtained by fluorescence measurements of the amount of nuclear proteins in murine tail fibroblast (MTF) undergoing cellular senescence. Our model provides a three-parameter stationary distribution that is in good agreement with the experimental data even during the transition to the senescent state, where the nuclear protein concentration changes abruptly. The estimation of three parameters (cooperativity, saturation threshold, and maximal velocity of the reaction), and their evolution during replicative passages shows that only the maximal velocity varies significantly. Based on our modeling we speculate the reduction of functionality of the protein degradation mechanism as a possible competitive inhibition of the proteasome. PMID:26115222

  14. MINOR PARAMETERS NEEDED FOR INDIVIDUAL-DOSE CALCULATIONS: Final Report for Tasks 7.1, 7.2, 8.1, 8.2, 9.1, 9.2, and 9.3

    SciTech Connect

    Anspaugh, L. R.; Napier, Bruce A.

    2009-10-23

    This brief report documents the selection of parameters needed to support individual-dose calculations from 131I released into the environment with gaseous effluents from the Mayak Production Association.

  15. Extracting cellular automaton rules from physical Langevin equation models for single and collective cell migration.

    PubMed

    Nava-Sedeño, J M; Hatzikirou, H; Peruani, F; Deutsch, A

    2017-02-27

    Cellular automata (CA) are discrete time, space, and state models which are extensively used for modeling biological phenomena. CA are "on-lattice" models with low computational demands. In particular, lattice-gas cellular automata (LGCA) have been introduced as models of single and collective cell migration. The interaction rule dictates the behavior of a cellular automaton model and is critical to the model's biological relevance. The LGCA model's interaction rule has been typically chosen phenomenologically. In this paper, we introduce a method to obtain lattice-gas cellular automaton interaction rules from physically-motivated "off-lattice" Langevin equation models for migrating cells. In particular, we consider Langevin equations related to single cell movement (movement of cells independent of each other) and collective cell migration (movement influenced by cell-cell interactions). As examples of collective cell migration, two different alignment mechanisms are studied: polar and nematic alignment. Both kinds of alignment have been observed in biological systems such as swarms of amoebae and myxobacteria. Polar alignment causes cells to align their velocities parallel to each other, whereas nematic alignment drives cells to align either parallel or antiparallel to each other. Under appropriate assumptions, we have derived the LGCA transition probability rule from the steady-state distribution of the off-lattice Fokker-Planck equation. Comparing alignment order parameters between the original Langevin model and the derived LGCA for both mechanisms, we found different areas of agreement in the parameter space. Finally, we discuss potential reasons for model disagreement and propose extensions to the CA rule derivation methodology.

  16. Silver Nanoparticle-Mediated Cellular Responses in Various Cell Lines: An in Vitro Model

    PubMed Central

    Zhang, Xi-Feng; Shen, Wei; Gurunathan, Sangiliyandi

    2016-01-01

    Silver nanoparticles (AgNPs) have attracted increased interest and are currently used in various industries including medicine, cosmetics, textiles, electronics, and pharmaceuticals, owing to their unique physical and chemical properties, particularly as antimicrobial and anticancer agents. Recently, several studies have reported both beneficial and toxic effects of AgNPs on various prokaryotic and eukaryotic systems. To develop nanoparticles for mediated therapy, several laboratories have used a variety of cell lines under in vitro conditions to evaluate the properties, mode of action, differential responses, and mechanisms of action of AgNPs. In vitro models are simple, cost-effective, rapid, and can be used to easily assess efficacy and performance. The cytotoxicity, genotoxicity, and biocompatibility of AgNPs depend on many factors such as size, shape, surface charge, surface coating, solubility, concentration, surface functionalization, distribution of particles, mode of entry, mode of action, growth media, exposure time, and cell type. Cellular responses to AgNPs are different in each cell type and depend on the physical and chemical nature of AgNPs. This review evaluates significant contributions to the literature on biological applications of AgNPs. It begins with an introduction to AgNPs, with particular attention to their overall impact on cellular effects. The main objective of this review is to elucidate the reasons for different cell types exhibiting differential responses to nanoparticles even when they possess similar size, shape, and other parameters. Firstly, we discuss the cellular effects of AgNPs on a variety of cell lines; Secondly, we discuss the mechanisms of action of AgNPs in various cellular systems, and try to elucidate how AgNPs interact with different mammalian cell lines and produce significant effects; Finally, we discuss the cellular activation of various signaling molecules in response to AgNPs, and conclude with future perspectives

  17. Cavity theory applications for kilovoltage cellular dosimetry.

    PubMed

    Oliver, Patricia A K; Thomson, Rowan

    2017-03-30

    Relationships between macroscopic (bulk tissue) and microscopic (cellular) dose 
descriptors are investigated using cavity theory and Monte Carlo (MC) simulations. 
Small, large, and multiple intermediate cavity theory (SCT, LCT, and ICT, respectively) approaches are considered for 20 to 370 keV incident photons; ICT is a sum 
of SCT and LCT contributions weighted by parameter d. Considering μm-sized cavities of water in bulk tissue phantoms, different cavity theory approaches are evaluated 
via comparison of Dw,m/Dm,m (where Dw,m is dose-to-water-in-medium and Dm,m is 
dose-to-medium-in-medium) with MC results. The best overall agreement is achieved 
with an ICT approach in which d=(1-e-βL)/(βL), where L is the mean chord length 
of the cavity and β is given by e-βRCSDA=0.04 (RCSDA is the continuous slowing 
down approximation range of an electron of energy equal to that of incident photons). 
Cell nucleus doses, Dnuc, computed with this ICT approach are compared with those 
from MC simulations involving multicellular soft tissue models considering a representative range of cell/nucleus sizes and elemental compositions. In 91% of cases, ICT and 
MC predictions agree within 3%; disagreement is at most 8.8%. These results suggest 
that cavity theory may be useful for linking doses from model-based dose calculation 
algorithms (MBDCAs) with energy deposition in cellular targets. Finally, based on 
the suggestion that clusters of water molecules associated with DNA are important 
radiobiological targets, two approaches for estimating dose-to-water by application of 
SCT to MC results for Dm,m or Dnuc are compared. Results for these two estimates 
differ by up to 35%, demonstrating the sensitivity of energy

  18. 47 CFR 22.909 - Cellular markets.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Cellular markets. 22.909 Section 22.909... Cellular Radiotelephone Service § 22.909 Cellular markets. Cellular markets are standard geographic areas used by the FCC for administrative convenience in the licensing of cellular systems. Cellular...

  19. 47 CFR 22.909 - Cellular markets.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Cellular markets. 22.909 Section 22.909... Cellular Radiotelephone Service § 22.909 Cellular markets. Cellular markets are standard geographic areas used by the FCC for administrative convenience in the licensing of cellular systems. Cellular...

  20. 47 CFR 22.909 - Cellular markets.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Cellular markets. 22.909 Section 22.909... Cellular Radiotelephone Service § 22.909 Cellular markets. Cellular markets are standard geographic areas used by the FCC for administrative convenience in the licensing of cellular systems. Cellular...

  1. 47 CFR 22.909 - Cellular markets.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Cellular markets. 22.909 Section 22.909... Cellular Radiotelephone Service § 22.909 Cellular markets. Cellular markets are standard geographic areas used by the FCC for administrative convenience in the licensing of cellular systems. Cellular...

  2. 47 CFR 22.909 - Cellular markets.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Cellular markets. 22.909 Section 22.909... Cellular Radiotelephone Service § 22.909 Cellular markets. Cellular markets are standard geographic areas used by the FCC for administrative convenience in the licensing of cellular systems. Cellular...

  3. Gas Transfer in Cellularized Collagen-Membrane Gas Exchange Devices

    PubMed Central

    Lo, Justin H.; Bassett, Erik K.; Penson, Elliot J. N.; Hoganson, David M.

    2015-01-01

    Chronic lower respiratory disease is highly prevalent in the United States, and there remains a need for alternatives to lung transplant for patients who progress to end-stage lung disease. Portable or implantable gas oxygenators based on microfluidic technologies can address this need, provided they operate both efficiently and biocompatibly. Incorporating biomimetic materials into such devices can help replicate native gas exchange function and additionally support cellular components. In this work, we have developed microfluidic devices that enable blood gas exchange across ultra-thin collagen membranes (as thin as 2 μm). Endothelial, stromal, and parenchymal cells readily adhere to these membranes, and long-term culture with cellular components results in remodeling, reflected by reduced membrane thickness. Functionally, acellular collagen-membrane lung devices can mediate effective gas exchange up to ∼288 mL/min/m2 of oxygen and ∼685 mL/min/m2 of carbon dioxide, approaching the gas exchange efficiency noted in the native lung. Testing several configurations of lung devices to explore various physical parameters of the device design, we concluded that thinner membranes and longer gas exchange distances result in improved hemoglobin saturation and increases in pO2. However, in the design space tested, these effects are relatively small compared to the improvement in overall oxygen and carbon dioxide transfer by increasing the blood flow rate. Finally, devices cultured with endothelial and parenchymal cells achieved similar gas exchange rates compared with acellular devices. Biomimetic blood oxygenator design opens the possibility of creating portable or implantable microfluidic devices that achieve efficient gas transfer while also maintaining physiologic conditions. PMID:26020102

  4. Gas Transfer in Cellularized Collagen-Membrane Gas Exchange Devices.

    PubMed

    Lo, Justin H; Bassett, Erik K; Penson, Elliot J N; Hoganson, David M; Vacanti, Joseph P

    2015-08-01

    Chronic lower respiratory disease is highly prevalent in the United States, and there remains a need for alternatives to lung transplant for patients who progress to end-stage lung disease. Portable or implantable gas oxygenators based on microfluidic technologies can address this need, provided they operate both efficiently and biocompatibly. Incorporating biomimetic materials into such devices can help replicate native gas exchange function and additionally support cellular components. In this work, we have developed microfluidic devices that enable blood gas exchange across ultra-thin collagen membranes (as thin as 2 μm). Endothelial, stromal, and parenchymal cells readily adhere to these membranes, and long-term culture with cellular components results in remodeling, reflected by reduced membrane thickness. Functionally, acellular collagen-membrane lung devices can mediate effective gas exchange up to ∼288 mL/min/m(2) of oxygen and ∼685 mL/min/m(2) of carbon dioxide, approaching the gas exchange efficiency noted in the native lung. Testing several configurations of lung devices to explore various physical parameters of the device design, we concluded that thinner membranes and longer gas exchange distances result in improved hemoglobin saturation and increases in pO2. However, in the design space tested, these effects are relatively small compared to the improvement in overall oxygen and carbon dioxide transfer by increasing the blood flow rate. Finally, devices cultured with endothelial and parenchymal cells achieved similar gas exchange rates compared with acellular devices. Biomimetic blood oxygenator design opens the possibility of creating portable or implantable microfluidic devices that achieve efficient gas transfer while also maintaining physiologic conditions.

  5. Final Report

    SciTech Connect

    Marchant, Gary E.

    2013-04-23

    This is the final report of a two year project entitled "Governing Nanotechnology Risks and Benefits in the Transition to Regulation: Innovative Public and Private Approaches." This project examined the role of new governance or "soft law" mechanisms such as codes of conduct, voluntary programs and partnership agreements to manage the risks of emerging technologies such as nanotechnology. A series of published or in publication papers and book chapters are attached.

  6. Final Report

    SciTech Connect

    R. Paul Drake

    2001-11-30

    This final report describes work involving 22 investigators from 11 institutions to explore the dynamics present in supernova explosions by means of experiments on the Omega laser. The specific experiments emphasized involved the unstable expansion of a spherical capsule and the coupling of perturbations at a first interface to a second interface by means of a strong shock. Both effects are present in supernovae. The experiments were performed at Omega and the computer simulations were undertaken at several institutions. B139

  7. Final Report

    SciTech Connect

    Stinis, Panos

    2016-08-07

    This is the final report for the work conducted at the University of Minnesota (during the period 12/01/12-09/18/14) by PI Panos Stinis as part of the "Collaboratory on Mathematics for Mesoscopic Modeling of Materials" (CM4). CM4 is a multi-institution DOE-funded project whose aim is to conduct basic and applied research in the emerging field of mesoscopic modeling of materials.

  8. Astrobiological Complexity with Probabilistic Cellular Automata

    NASA Astrophysics Data System (ADS)

    Vukotić, Branislav; Ćirković, Milan M.

    2012-08-01

    The search for extraterrestrial life and intelligence constitutes one of the major endeavors in science, but has yet been quantitatively modeled only rarely and in a cursory and superficial fashion. We argue that probabilistic cellular automata (PCA) represent the best quantitative framework for modeling the astrobiological history of the Milky Way and its Galactic Habitable Zone. The relevant astrobiological parameters are to be modeled as the elements of the input probability matrix for the PCA kernel. With the underlying simplicity of the cellular automata constructs, this approach enables a quick analysis of large and ambiguous space of the input parameters. We perform a simple clustering analysis of typical astrobiological histories with "Copernican" choice of input parameters and discuss the relevant boundary conditions of practical importance for planning and guiding empirical astrobiological and SETI projects. In addition to showing how the present framework is adaptable to more complex situations and updated observational databases from current and near-future space missions, we demonstrate how numerical results could offer a cautious rationale for continuation of practical SETI searches.

  9. Astrobiological complexity with probabilistic cellular automata.

    PubMed

    Vukotić, Branislav; Ćirković, Milan M

    2012-08-01

    The search for extraterrestrial life and intelligence constitutes one of the major endeavors in science, but has yet been quantitatively modeled only rarely and in a cursory and superficial fashion. We argue that probabilistic cellular automata (PCA) represent the best quantitative framework for modeling the astrobiological history of the Milky Way and its Galactic Habitable Zone. The relevant astrobiological parameters are to be modeled as the elements of the input probability matrix for the PCA kernel. With the underlying simplicity of the cellular automata constructs, this approach enables a quick analysis of large and ambiguous space of the input parameters. We perform a simple clustering analysis of typical astrobiological histories with "Copernican" choice of input parameters and discuss the relevant boundary conditions of practical importance for planning and guiding empirical astrobiological and SETI projects. In addition to showing how the present framework is adaptable to more complex situations and updated observational databases from current and near-future space missions, we demonstrate how numerical results could offer a cautious rationale for continuation of practical SETI searches.

  10. Geolocation Technologies Final Report

    SciTech Connect

    Magnoli, D E

    2003-06-02

    This paper is the final report for LL998 In Situ Sensing Subtask 7 (Geo-location) undertaken for NNSA NA-22 enabling technologies R&D for Counterproliferation Detection. A few state-of-the-art resolution parameters are presented for accelerometers, indoor and outdoor GPS (Global Positioning Satellite) systems, and INSs (Inertial Navigation Systems). New technologies are described, including one which has demonstrated the ability to track within a building to a resolution of under a foot.

  11. MSAT and cellular hybrid networking

    NASA Technical Reports Server (NTRS)

    Baranowsky, Patrick W., II

    1993-01-01

    Westinghouse Electric Corporation is developing both the Communications Ground Segment and the Series 1000 Mobile Phone for American Mobile Satellite Corporation's (AMSC's) Mobile Satellite (MSAT) system. The success of the voice services portion of this system depends, to some extent, upon the interoperability of the cellular network and the satellite communication circuit switched communication channels. This paper will describe the set of user-selectable cellular interoperable modes (cellular first/satellite second, etc.) provided by the Mobile Phone and described how they are implemented with the ground segment. Topics including roaming registration and cellular-to-satellite 'seamless' call handoff will be discussed, along with the relevant Interim Standard IS-41 Revision B Cellular Radiotelecommunications Intersystem Operations and IOS-553 Mobile Station - Land Station Compatibility Specification.

  12. Final Report

    SciTech Connect

    R Paul Drake

    2004-01-12

    OAK-B135 This is the final report from the project Hydrodynamics by High-Energy-Density Plasma Flow and Hydrodynamics and Radiation Hydrodynamics with Astrophysical Applications. This project supported a group at the University of Michigan in the invention, design, performance, and analysis of experiments using high-energy-density research facilities. The experiments explored compressible nonlinear hydrodynamics, in particular at decelerating interfaces, and the radiation hydrodynamics of strong shock waves. It has application to supernovae, astrophysical jets, shock-cloud interactions, and radiative shock waves.

  13. Effect of canopy structure and open-top chamber techniques on micrometeorological parameters and the gradients and transport of water vapor, carbon dioxide and ozone in the canopies of plum trees (`prunus salicina`) in the San Joaquin valley. Final report

    SciTech Connect

    Grantz, D.A.; Vaughn, D.L.; Metheny, P.A.; Malkus, P.; Wosnik, K.

    1995-03-15

    Plum trees (Prunus salicina cv. Casselman) were exposed to ozone in open-top chambers (OTC) or chamberless plots, and trace gas concentrations and microenvironmental conditions were monitored within tree canopies inside the outside the OTC. Concentrations of ozone, carbon dioxide and water vapor, leaf and air temperature, light intensity, and wind speed were measured at nine positions in the tree canopies. The objectives were to: (1) map the distribution of microenvironmental parameters within the canopies inside and outside the OTC; (2) determine transport parameters for gas exchange, and (3) calculate ozone flux. Significant vertical and horizontal gradients were observed; gradients were diminished and often inverted inside relative to outside the OTC due to air distribution at the bottom of the OCT. Ozone flux was readily modeled from measures of stomatal conductance, nonstomatal conductance and ozone concentration at the leaf surface.

  14. A cellular automaton nanoflare model of coronal loops

    NASA Astrophysics Data System (ADS)

    Lopez Fuentes, Marcelo; Klimchuk, James

    In Lopez-Fuentes, Klimchuk and Mandrini (2007) we found that the evolution of soft X-ray loops can be separated into three main phases that suggest the development, maintainance, and decay of a self-organized system. Here, we present a cellular automaton model that reproduces the main features of the observed evolution. The model is based on the idea that loops are made of multiple unresolved strands which have footpoints that are displaced by random photospheric motions (Parker 1988). In this scenario, there is a continuous increase of the magnetic stress between neighboring strands until a critical stress is reached and the accumulated energy is suddenly released by reconnection. Each of these reconnection "events" is associated with a nanoflare. Using the EBTEL hydrodynamic code (Klimchuk, Patsourakos and Cargill 2008) to model the plasma response we construct synthetic light curves that we compare with the observations. We also study how the properties of the light curves scale with the different parameters of the model. Finally, we discuss how the present model can be used to explain loop observations in different wavelengths.

  15. Four faces of cellular senescence

    PubMed Central

    Rodier, Francis

    2011-01-01

    Cellular senescence is an important mechanism for preventing the proliferation of potential cancer cells. Recently, however, it has become apparent that this process entails more than a simple cessation of cell growth. In addition to suppressing tumorigenesis, cellular senescence might also promote tissue repair and fuel inflammation associated with aging and cancer progression. Thus, cellular senescence might participate in four complex biological processes (tumor suppression, tumor promotion, aging, and tissue repair), some of which have apparently opposing effects. The challenge now is to understand the senescence response well enough to harness its benefits while suppressing its drawbacks. PMID:21321098

  16. A magnetically actuated cellular strain assessment tool for quantitative analysis of strain induced cellular reorientation and actin alignment

    NASA Astrophysics Data System (ADS)

    Khademolhosseini, F.; Liu, C.-C.; Lim, C. J.; Chiao, M.

    2016-08-01

    Commercially available cell strain tools, such as pneumatically actuated elastomer substrates, require special culture plates, pumps, and incubator setups. In this work, we present a magnetically actuated cellular strain assessment tool (MACSAT) that can be implemented using off-the-shelf components and conventional incubators. We determine the strain field on the MACSAT elastomer substrate using numerical models and experimental measurements and show that a specific region of the elastomer substrate undergoes a quasi-uniaxial 2D stretch, and that cells confined to this region of the MACSAT elastomer substrate undergo tensile, compressive, or zero axial strain depending on their angle of orientation. Using the MACSAT to apply cyclic strain on endothelial cells, we demonstrate that actin filaments within the cells reorient away from the stretching direction, towards the directions of minimum axial strain. We show that the final actin orientation angles in strained cells are spread over a region of compressive axial strain, confirming previous findings on the existence of a varied pre-tension in the actin filaments of the cytoskeleton. We also demonstrate that strained cells exhibit distinctly different values of actin alignment coherency compared to unstrained cells and therefore propose that this parameter, i.e., the coherency of actin alignment, can be used as a new readout to determine the occurrence/extent of actin alignment in cell strain experiments. The tools and methods demonstrated in this study are simple and accessible and can be easily replicated by other researchers to study the strain response of other adherent cells.

  17. Origami interleaved tube cellular materials

    NASA Astrophysics Data System (ADS)

    Cheung, Kenneth C.; Tachi, Tomohiro; Calisch, Sam; Miura, Koryo

    2014-09-01

    A novel origami cellular material based on a deployable cellular origami structure is described. The structure is bi-directionally flat-foldable in two orthogonal (x and y) directions and is relatively stiff in the third orthogonal (z) direction. While such mechanical orthotropicity is well known in cellular materials with extruded two dimensional geometry, the interleaved tube geometry presented here consists of two orthogonal axes of interleaved tubes with high interfacial surface area and relative volume that changes with fold-state. In addition, the foldability still allows for fabrication by a flat lamination process, similar to methods used for conventional expanded two dimensional cellular materials. This article presents the geometric characteristics of the structure together with corresponding kinematic and mechanical modeling, explaining the orthotropic elastic behavior of the structure with classical dimensional scaling analysis.

  18. A Course in Cellular Bioengineering.

    ERIC Educational Resources Information Center

    Lauffenburger, Douglas A.

    1989-01-01

    Gives an overview of a course in chemical engineering entitled "Cellular Bioengineering," dealing with how chemical engineering principles can be applied to molecular cell biology. Topics used are listed and some key references are discussed. Listed are 85 references. (YP)

  19. Aircraft parameter estimation

    NASA Technical Reports Server (NTRS)

    Iliff, Kenneth W.

    1987-01-01

    The aircraft parameter estimation problem is used to illustrate the utility of parameter estimation, which applies to many engineering and scientific fields. Maximum likelihood estimation has been used to extract stability and control derivatives from flight data for many years. This paper presents some of the basic concepts of aircraft parameter estimation and briefly surveys the literature in the field. The maximum likelihood estimator is discussed, and the basic concepts of minimization and estimation are examined for a simple simulated aircraft example. The cost functions that are to be minimized during estimation are defined and discussed. Graphic representations of the cost functions are given to illustrate the minimization process. Finally, the basic concepts are generalized, and estimation from flight data is discussed. Some of the major conclusions for the simulated example are also developed for the analysis of flight data from the F-14, highly maneuverable aircraft technology (HiMAT), and space shuttle vehicles.

  20. Target parameter estimation

    NASA Technical Reports Server (NTRS)

    Hocking, W. K.

    1989-01-01

    The objective of any radar experiment is to determine as much as possible about the entities which scatter the radiation. This review discusses many of the various parameters which can be deduced in a radar experiment, and also critically examines the procedures used to deduce them. Methods for determining the mean wind velocity, the RMS fluctuating velocities, turbulence parameters, and the shapes of the scatterers are considered. Complications with these determinations are discussed. It is seen throughout that a detailed understanding of the shape and cause of the scatterers is important in order to make better determinations of these various quantities. Finally, some other parameters, which are less easily acquired, are considered. For example, it is noted that momentum fluxes due to buoyancy waves and turbulence can be determined, and on occasions radars can be used to determine stratospheric diffusion coefficients and even temperature profiles in the atmosphere.

  1. Mathematical Modeling of Cellular Metabolism.

    PubMed

    Berndt, Nikolaus; Holzhütter, Hermann-Georg

    Cellular metabolism basically consists of the conversion of chemical compounds taken up from the extracellular environment into energy (conserved in energy-rich bonds of organic phosphates) and a wide array of organic molecules serving as catalysts (enzymes), information carriers (nucleic acids), and building blocks for cellular structures such as membranes or ribosomes. Metabolic modeling aims at the construction of mathematical representations of the cellular metabolism that can be used to calculate the concentration of cellular molecules and the rates of their mutual chemical interconversion in response to varying external conditions as, for example, hormonal stimuli or supply of essential nutrients. Based on such calculations, it is possible to quantify complex cellular functions as cellular growth, detoxification of drugs and xenobiotic compounds or synthesis of exported molecules. Depending on the specific questions to metabolism addressed, the methodological expertise of the researcher, and available experimental information, different conceptual frameworks have been established, allowing the usage of computational methods to condense experimental information from various layers of organization into (self-) consistent models. Here, we briefly outline the main conceptual frameworks that are currently exploited in metabolism research.

  2. Final Report

    SciTech Connect

    David A. Benson

    2012-09-24

    This project combines outcrop-scale heterogeneity characterization, laboratory experiments, and numerical simulations. The study is designed to test whether established dispersion theory accurately predicts the behavior of solute transport through heterogeneous media and to investigate the relationship between heterogeneity and the parameters that populate these models. The dispersion theory tested by this work is based upon the fractional advection-dispersion equation (fADE) model. Unlike most dispersion studies that develop a solute transport model by fitting the solute transport breakthrough curve, this project will explore the nature of the heterogeneous media to better understand the connection between the model parameters and the aquifer heterogeneity. Our work at the Colorado School of Mines was focused on the following questions: 1) What are the effects of multi-scale geologic variability on transport of conservative and reactive solutes? 2) Can those transport effects be accounted for by classical methods, and if not, can the nonlocal fractional-order equations provide better predictions? 3) Can the fractional-order equations be parameterized through a link to some simple observable geologic features? 4) Are the classical equations of transport and reaction sufficient? 5) What is the effect of anomalous transport on chemical reaction in groundwater systems? The work is predicated on the observation that upscaled transport is defined by loss of information, or spatio-temporal averaging. This averaging tends to make the transport laws such as Fick's 2nd-order diffusion equation similar to central limit theory. The fractional-order advection-dispersion equations rely on limit theory for heavy-tailed random motion that has some diverging moments. The equations predict larger tails of a plume in space and/or time than those predicted by the classical 2nd-order advection-dispersion equation. The heavy tails are often seen in plumes at field sites.

  3. Final Report

    SciTech Connect

    Webb, Robert C.; Kamon, Teruki; Toback, David; Safonov, Alexei; Dutta, Bhaskar; Dimitri, Nanopoulos; Pope, Christopher; White, James

    2013-11-18

    Overview The High Energy Physics Group at Texas A&M University is submitting this final report for our grant number DE-FG02-95ER40917. This grant has supported our wide range of research activities for over a decade. The reports contained here summarize the latest work done by our research team. Task A (Collider Physics Program): CMS & CDF Profs. T. Kamon, A. Safonov, and D. Toback co-lead the Texas A&M (TAMU) collider program focusing on CDF and CMS experiments. Task D: Particle Physics Theory Our particle physics theory task is the combined effort of Profs. B. Dutta, D. Nanopoulos, and C. Pope. Task E (Underground Physics): LUX & NEXT Profs. R. Webb and J. White(deceased) lead the Xenon-based underground research program consisting of two main thrusts: the first, participation in the LUX two-phase xenon dark matter search experiment and the second, detector R&D primarily aimed at developing future detectors for underground physics (e.g. NEXT and LZ).

  4. Sound attenuation characteristics of cellular metamaterials

    NASA Astrophysics Data System (ADS)

    Varanasi, Satya Surya Srinivas

    could be mitigated by the addition of appropriate treatments such as a lightweight grid that modified the incident sound field to be normally directed. Although the performance of the metamaterial-based barrier solutions was better compared to the conventional ones, the performance can be poor at the system eigenfrequencies. The possibility of shifting energy from the deficit bands to other regions where the barriers are more efficient was numerically explored for embodiments of segmented cellular materials having non-linear stiffness characteristics. The acoustical behavior of such materials was probed through representative two-dimensional models of a segmented plate with a contact interface. Super-harmonic response peaks were observed for pure harmonic excitations, the strength of which were found to strongly depend on the degree of non-linearity or bilinear stiffness ratio. The closer an excitation frequency was to the characteristic eigenfrequencies of the structure, the stronger was the super-harmonic response, which supported the idea of transferring energy from problematic frequency bands to higher frequencies. Finally, the possibility of a spatial-shift of energy from longitudinal to lateral direction was explored with the idea of eliminating the design constraints associated with conventional absorbing materials, and with the hope of realizing a compact sound absorber. The embodiment was a two-phase chiral composite made using a Topologically Interlocked Material (TIM) with its unit cell being a tetrahedron consisting of two helicoid dissections. A comparative study was conducted with standard microstructures inspired by the Voigt and Reuss models. The twist mode of the chiral composites was found to be excited by an incident sound field normal to the plane of the TIM assembly. Although this behavior is not unique to a chiral microstructure, many other microstructures do not exhibit this behavior. The excitation of the twist mode by the incident sound field

  5. Multiple cellular cascades participate in long-term potentiation and in hippocampus-dependent learning

    PubMed Central

    Baudry, Michel; Zhu, Guoqi; Liu, Yan; Wang, Yubin; Briz, Victor; Bi, Xiaoning

    2015-01-01

    Since its discovery by Bliss and Lomo, the phenomenon of long-term potentiation (LTP) has been extensively studied, as it was viewed as a potential cellular mechanism of learning and memory. Over the years, many signaling cascades have been implicated in its induction, consolidation and maintenance, raising questions regarding its real significance. Here, we review several of the most commonly studies signaling cascades and discuss how they converge on a common set of mechanisms likely to be involved in the maintenance of LTP. We further argue that the existence of cross-talks between these different signaling cascades can not only account for several discrepancies in the literature, but also account for the existence of different forms of LTP, which can be engaged by different types of stimulus parameters under different experimental conditions. Finally, we discuss how the understanding of the diversity of LTP mechanisms can help us understand the diversity of the types of learning and memory. PMID:25482663

  6. Supergranular Parameters

    NASA Astrophysics Data System (ADS)

    Udayashankar, Paniveni

    2016-07-01

    I study the complexity of supergranular cells using intensity patterns from Kodaikanal solar observatory. The chaotic and turbulent aspect of the solar supergranulation can be studied by examining the interrelationships amongst the parameters characterizing supergranular cells namely size, horizontal flow field, lifetime and physical dimensions of the cells and the fractal dimension deduced from the size data. The findings are supportive of Kolmogorov's theory of turbulence. The Data consists of visually identified supergranular cells, from which a fractal dimension 'D' for supergranulation is obtained according to the relation P α AD/2 where 'A' is the area and 'P' is the perimeter of the supergranular cells. I find a fractal dimension close to about 1.3 which is consistent with that for isobars and suggests a possible turbulent origin. The cell circularity shows a dependence on the perimeter with a peak around (1.1-1.2) x 105 m. The findings are supportive of Kolmogorov's theory of turbulence.

  7. Classifying cellular automata using grossone

    NASA Astrophysics Data System (ADS)

    D'Alotto, Louis

    2016-10-01

    This paper proposes an application of the Infinite Unit Axiom and grossone, introduced by Yaroslav Sergeyev (see [7] - [12]), to the development and classification of one and two-dimensional cellular automata. By the application of grossone, new and more precise nonarchimedean metrics on the space of definition for one and two-dimensional cellular automata are established. These new metrics allow us to do computations with infinitesimals. Hence configurations in the domain space of cellular automata can be infinitesimally close (but not equal). That is, they can agree at infinitely many places. Using the new metrics, open disks are defined and the number of points in each disk computed. The forward dynamics of a cellular automaton map are also studied by defined sets. It is also shown that using the Infinite Unit Axiom, the number of configurations that follow a given configuration, under the forward iterations of cellular automaton maps, can now be computed and hence a classification scheme developed based on this computation.

  8. Final Report

    SciTech Connect

    Taylor, Philip L.

    2012-11-11

    Our research program was aimed at elucidating the nature of proton transport in ionomer membranes by means of a combination of analytical theory and molecular modeling. There were two broad thrusts. The first of these was directed towards understanding the equilibrium structure of Nafion and related polymers at various levels of hydration. The second thrust was concerned with the transport of protons through a membrane of this type. The research on structure proceeded by building on existing work, but with the introduction of some novel techniques, among which is a hybrid Molecular Dynamics--Monte Carlo approach. This method permits rapid computations by temporarily decoupling the motion of the polar side chains from that of the perfluorinated backbone, while still retaining the essential aspects of the constraint that phase separation can only continue to a very limited degree. Competition between an elastic energy due to this constraint and the tendency to phase separation lead to the equilibrium structure, which turns out to be qualitatively different at different levels of hydration. The use of a carefully formulated dielectric function was necessary to achieve accurate results. The work on transport of protons in Nafion-like membranes also involved a combination of theory and simulation. Atomistic molecular-dynamics simulations were employed to determine some of the characteristic parameters for the diffusion of hydronium in hydrated membranes. These results were used in a theoretical model of non-linear diffusion to predict transport coefficients. Among our results was the discovery that treatment with strong electric fields may enhance the properties of the polymer membranes. Our computer simulations showed that the vigorous application of a stretching force or an electric field can modify the structure of the ionomer that lies at the heart of a polymer-electrolyte-membrane fuel cell. If these predictions are verified experimentally, then it should be

  9. STS 65 Final Report

    NASA Technical Reports Server (NTRS)

    Rice, James E.

    1996-01-01

    The report is organized into sections representing the phases of work performed in analyzing the STS 65 results and preparing the instrument for STS 73. Section 1 briefly outlines the Orbital Acceleration Research Experiment (OARE) system features, coordinates, and measurement parameters. Section 2 describes the results from STS 65. The mission description, data calibration, and representative data obtained on STS 65 are presented. Also, the anomalous performance of OARE on STS 65 is discussed. Finally, Section 3 presents a discussion of accuracy achieved and achievable with OARE.

  10. Fracture mechanics of cellular glass

    NASA Technical Reports Server (NTRS)

    Zwissler, J. G.; Adams, M. A.

    1981-01-01

    The fracture mechanics of cellular glasses (for the structural substrate of mirrored glass for solr concentrator reflecting panels) are discussed. Commercial and developmental cellular glasses were tested and analyzed using standard testing techniques and models developed from linear fracture mechanics. Two models describing the fracture behavior of these materials were developed. Slow crack growth behavior in cellular glass was found to be more complex than that encountered in dense glasses or ceramics. The crack velocity was found to be strongly dependent upon water vapor transport to the tip of the moving crack. The existence of a static fatigue limit was not conclusively established, however, it is speculated that slow crack growth behavior in Region 1 may be slower, by orders of magnitude, than that found in dense glasses.

  11. Cellular-based preemption system

    NASA Technical Reports Server (NTRS)

    Bachelder, Aaron D. (Inventor)

    2011-01-01

    A cellular-based preemption system that uses existing cellular infrastructure to transmit preemption related data to allow safe passage of emergency vehicles through one or more intersections. A cellular unit in an emergency vehicle is used to generate position reports that are transmitted to the one or more intersections during an emergency response. Based on this position data, the one or more intersections calculate an estimated time of arrival (ETA) of the emergency vehicle, and transmit preemption commands to traffic signals at the intersections based on the calculated ETA. Additional techniques may be used for refining the position reports, ETA calculations, and the like. Such techniques include, without limitation, statistical preemption, map-matching, dead-reckoning, augmented navigation, and/or preemption optimization techniques, all of which are described in further detail in the above-referenced patent applications.

  12. Cellular models for Parkinson's disease.

    PubMed

    Falkenburger, Björn H; Saridaki, Theodora; Dinter, Elisabeth

    2016-10-01

    Developing new therapeutic strategies for Parkinson's disease requires cellular models. Current models reproduce the two most salient changes found in the brains of patients with Parkinson's disease: The degeneration of dopaminergic neurons and the existence of protein aggregates consisting mainly of α-synuclein. Cultured cells offer many advantages over studying Parkinson's disease directly in patients or in animal models. At the same time, the choice of a specific cellular model entails the requirement to focus on one aspect of the disease while ignoring others. This article is intended for researchers planning to use cellular models for their studies. It describes for commonly used cell types the aspects of Parkinson's disease they model along with technical advantages and disadvantages. It might also be helpful for researchers from other fields consulting literature on cellular models of Parkinson's disease. Important models for the study of dopaminergic neuron degeneration include Lund human mesencephalic cells and primary neurons, and a case is made for the use of non-dopaminergic cells to model pathogenesis of non-motor symptoms of Parkinson's disease. With regard to α-synuclein aggregates, this article describes strategies to induce and measure aggregates with a focus on fluorescent techniques. Cellular models reproduce the two most salient changes of Parkinson's disease, the degeneration of dopaminergic neurons and the existence of α-synuclein aggregates. This article is intended for researchers planning to use cellular models for their studies. It describes for commonly used cell types and treatments the aspects of Parkinson's disease they model along with technical advantages and disadvantages. Furthermore, this article describes strategies to induce and measure aggregates with a focus on fluorescent techniques. This article is part of a special issue on Parkinson disease.

  13. Genetic Algorithm Calibration of Probabilistic Cellular Automata for Modeling Mining Permit Activity

    USGS Publications Warehouse

    Louis, S.J.; Raines, G.L.

    2003-01-01

    We use a genetic algorithm to calibrate a spatially and temporally resolved cellular automata to model mining activity on public land in Idaho and western Montana. The genetic algorithm searches through a space of transition rule parameters of a two dimensional cellular automata model to find rule parameters that fit observed mining activity data. Previous work by one of the authors in calibrating the cellular automaton took weeks - the genetic algorithm takes a day and produces rules leading to about the same (or better) fit to observed data. These preliminary results indicate that genetic algorithms are a viable tool in calibrating cellular automata for this application. Experience gained during the calibration of this cellular automata suggests that mineral resource information is a critical factor in the quality of the results. With automated calibration, further refinements of how the mineral-resource information is provided to the cellular automaton will probably improve our model.

  14. FINAL REPORT

    SciTech Connect

    PETER, GARY F.

    2014-07-16

    of biomass samples imaged with all three methods, and using common analytical software to quantify parameters from the three dimensional images. In addition to the proposed experiments, we conducted imaging studies with a novel TOF-SIMS instrument available through collaborations with the AMOLF goup led by Ron Heeren at the FOM Institute in Amersterdam, Netherlands. ToF-SIMS was used to image intact cross sections of Populus stems with high spatial resolution, chemically selectivity. ToF-SIMS images were correlated with fluorescence microscopy which allowed for more positive ion identification.

  15. Final Report

    NASA Technical Reports Server (NTRS)

    Linsky, Jeffrey L.

    1998-01-01

    This grant was made to fund two accepted proposals to observe with the ASCA satellite: (1) Debunking the myth of two-temperature coronae of active stars, and (2) Dynamic coronae of dMe stars. We obtained the requested observations and have now completed two papers that will be published in the Astrophysical Journal. The RS CVn binary star UX Ari was observed for 14 hours with all four detectors onboard the ASCA satellite. The X-ray emission was at a constant, quiescent level during the first 12 hours, after which time a powerful flare with a peak luminosity of 1.4 x 10(exp 32) ergs/s started. The flare was observed until shortly after its peak. We present a spectral and temporal analysis of the UX Ari observations and analyze the data with a two-ribbon flare model including estimates for cooling losses. A time-dependent reconstruction of the emission measure (EM) distribution shows that two separate plasma components evolve during the flare (one being identified with the quiescent EM). Most of the flare EM reaches temperatures between 50 MK and 100 MK or more. Magnetic confinement requires the loop arcade to be geometrically large, with length scales on the order of one stellar radius. The electron densities inferred from the model decrease from initial values around 10(exp 12)/cc early in the flare to about 10(exp 11)/cc at the flare peak. The best-fit models require surface magnetic field strengths of a few hundred G, compatible with the maximum photospheric fields expected from equipartition. The flare parameters imply a (conductive and radiative) cooling loss time of less than one hour at flare peak. The elemental abundances increase significantly during the flare rise, with the abundances of the low-FIP elements Fe, Mg, Si, and Ni typically increasing to higher levels than the high-FIP elements such as S or Ne. The Fe abundance increases from (17 +/- 4)% of the solar photospheric value during quiescence up to (89 +/- 18)% at flare peak. A fractionation process

  16. Cellular automata for traffic simulations

    NASA Astrophysics Data System (ADS)

    Wolf, Dietrich E.

    1999-02-01

    Traffic phenomena such as the transition from free to congested flow, lane inversion and platoon formation can be accurately reproduced using cellular automata. Being computationally extremely efficient, they simulate large traffic systems many times faster than real time so that predictions become feasible. A riview of recent results is given. The presence of metastable states at the jamming transition is discussed in detail. A simple new cellular automation is introduced, in which the interaction between cars is Galilei-invariant. It is shown that this type of interaction accounts for metastable states in a very natural way.

  17. Synthetic biology in cellular immunotherapy

    PubMed Central

    Chakravarti, Deboki; Wong, Wilson W.

    2015-01-01

    The adoptive transfer of genetically engineered T cells with cancer-targeting receptors has shown tremendous promise for eradicating tumors in clinical trials. This form of cellular immunotherapy presents a unique opportunity to incorporate advanced systems and synthetic biology approaches to create cancer therapeutics with novel functions. Here, we first review the development of synthetic receptors, switches, and circuits to control the location, duration, and strength of T cell activity against tumors. In addition, we discuss the cellular engineering and genome editing of host cells (or the chassis) to improve the efficacy of cell-based cancer therapeutics, and to reduce the time and cost of manufacturing. PMID:26088008

  18. Cellular basis of Alzheimer's disease.

    PubMed

    Bali, Jitin; Halima, Saoussen Ben; Felmy, Boas; Goodger, Zoe; Zurbriggen, Sebastian; Rajendran, Lawrence

    2010-12-01

    Alzheimer's disease (AD) is the most common form of neurodegenerative disease. A characteristic feature of the disease is the presence of amyloid-β (Aβ) which either in its soluble oligomeric form or in the plaque-associated form is causally linked to neurodegeneration. Aβ peptide is liberated from the membrane-spanning -amyloid precursor protein by sequential proteolytic processing employing β- and γ-secretases. All these proteins involved in the production of Aβ peptide are membrane associated and hence, membrane trafficking and cellular compartmentalization play important roles. In this review, we summarize the key cellular events that lead to the progression of AD.

  19. Superconducting quadrupoles for the SLC final focus

    SciTech Connect

    Erickson, R.; Fieguth, T.; Murray, J.J.

    1987-01-01

    The final focus system of the SLC will be upgraded by replacing the final quadrupoles with higher gradient superconducting magnets positioned closer to the interaction point. The parameters of the new system have been chosen to be compatible with the experimental detectors with a minimum of changes to other final focus components. These parameter choices are discussed along with the expected improvement in SLC performance.

  20. Final report

    SciTech Connect

    Dobbs, Fred C.

    2003-01-15

    species of flagellates, Spumella sp. and Bodo sp. (identifications are tentative) were isolated from South Oyster sediments by repetitive serial dilution/extinction method. Protistan cells were cultured with Cereal leaf Prescott medium and pelleted by centrifugation. Protistan DNAs were extracted with a DNA extraction kit (Sigma Co.) and the sequencing of their SSrDNA is underway. Finally, to follow up on our collaboration of Dr. Bill Johnson (Univ. of Utah), one of the co-PIs under the same NABIR umbrella, we are pleased to report we have successfully tested antibody-ferrographic capture of protists (See previous year's report for more background). Polyclonal FITC-conjugated antibody specific for a flagellate, Spumella sp., was produced by Rockland Inc., and we now are able to enumerate that species using ferrographic capture. There are, however, some issues of non-specific staining that remain to be resolved.

  1. Cellular commitment in the developing cerebellum

    PubMed Central

    Marzban, Hassan; Del Bigio, Marc R.; Alizadeh, Javad; Ghavami, Saeid; Zachariah, Robby M.; Rastegar, Mojgan

    2014-01-01

    The mammalian cerebellum is located in the posterior cranial fossa and is critical for motor coordination and non-motor functions including cognitive and emotional processes. The anatomical structure of cerebellum is distinct with a three-layered cortex. During development, neurogenesis and fate decisions of cerebellar primordium cells are orchestrated through tightly controlled molecular events involving multiple genetic pathways. In this review, we will highlight the anatomical structure of human and mouse cerebellum, the cellular composition of developing cerebellum, and the underlying gene expression programs involved in cell fate commitments in the cerebellum. A critical evaluation of the cell death literature suggests that apoptosis occurs in ~5% of cerebellar cells, most shortly after mitosis. Apoptosis and cellular autophagy likely play significant roles in cerebellar development, we provide a comprehensive discussion of their role in cerebellar development and organization. We also address the possible function of unfolded protein response in regulation of cerebellar neurogenesis. We discuss recent advancements in understanding the epigenetic signature of cerebellar compartments and possible connections between DNA methylation, microRNAs and cerebellar neurodegeneration. Finally, we discuss genetic diseases associated with cerebellar dysfunction and their role in the aging cerebellum. PMID:25628535

  2. Particles and Patterns in Cellular Automata

    SciTech Connect

    Jen, E.; Das, R.; Beasley, C.E.

    1999-06-03

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Our objective has been to develop tools for studying particle interactions in a class of dynamical systems characterized by discreteness, determinism, local interaction, and an inherently parallel form of evolution. These systems can be described by cellular automata (CA) and the behavior we studied has improved our understanding of the nature of patterns generated by CAs, their ability to perform global computations, and their relationship to continuous dynamical systems. We have also developed a rule-table mathematics that enables one to custom-design CA rule tables to generate patterns of specified types, or to perform specified computational tasks.

  3. Threshold effects and cellular recognition. Progress report

    SciTech Connect

    Rando, R R

    1980-01-01

    In the first year we focused on developing the techniques required for the successful incorporation of synthetic glycolipids into cells. To these ends a new water-soluble spacer group (8-amino-3-6-dioxaoctanoic acid) was developed and incorporated into the cholesterol based synthetic glycolipids. These glycolipids could be incorporated into liposomes, rendering them susceptible to aggregation by the appropriate lectin. They also allowed us to define the minimal distance between the sugar moiety and membrane required for agglutination. Finally and most importantly, we were able to functionally incorporate these new glycolipids in cells and render them agglutinable with the appropriate lectins. Functional incorporation does not occur with glycolipids bearing hydropholic spacer groups. We are now in a position to begin using the new glycolipids to answer questions about the roles of cell surface sugars in cellular recognition, which is the subject of this renewal proposal.

  4. Retrodifferentiation--a mechanism for cellular regeneration?

    PubMed

    Hass, Ralf

    2009-01-01

    Cellular differentiation can be characterized by the acquisition of specified properties during several steps of development whereby the original stem- or precursor-like populations can finally obtain a certain phenotype with highly specific cell functions. The continuing maturation process can be paralleled by progressively reduced proliferative capacity in various cell types functioning as postmitotic tissues. Conversely, other cell populations (e.g., distinct immune cells) may carry out their specific function upon stimulation of proliferation. While these differentiated phenotypes perform their appropriate specific duties throughout the functioning organism, nature may provide an interesting alternative within this concept of life: sometimes, differentiation steps appear to be reversible. Thus, retrograde differentiation--also termed retrodifferentiation--and accordingly rejuvenation may occur when differentiated cells lose their specific properties acquired during previous steps of maturation. Consequently, retrodifferentiation and rejuvenation could provide enormous potential for tissue repair and cell renewal; however, regulatory dysfunctions within these retrograde developments may also involve the risk of tumor promotion.

  5. Microsystems for cellular force measurement: a review

    NASA Astrophysics Data System (ADS)

    Rayne Zheng, Xiaoyu; Zhang, Xin

    2011-05-01

    Microsystems are providing key advances in studying single cell mechanical behavior. The mechanical interaction of cells with their extracellular matrix is fundamentally important for cell migration, division, phagocytosis and aptoptosis. This review reports the development of microsystems on studying cell forces. Microsystems provide advantages of studying single cells since the scale of cells is on the micron level. The components of microsystems provide culture, loading, guiding, trapping and on chip analysis of cellular mechanical forces. This paper gives overviews on how MEMS are advancing in the field of cell biomechno sensory systems. It presents different materials, and mode of studying cell mechanics. Finally, we comment on the future directions and challenges on the state of art techniques.

  6. Cellular Instabilities and Self-Acceleration of Expanding Spherical Flames

    NASA Technical Reports Server (NTRS)

    Law, C. K.; Kwon, O. C.

    2003-01-01

    In the present investigation we aim to provide experimental information on and thereby understanding of the generation and propagation of spark-ignited, outwardly propagating cellular flames, with three major focuses. The first is to unambiguously demonstrate the influence of the four most important parameters in inducing hydrodynamic and diffusional-thermal cellularities, namely thermal expansion, flame thickness, non-unity Lewis number, and global activation energy. The second is to investigate the critical state for the onset of cellularity for the stretch-affected, expanding flame. The third is to identify and consequently quantify the phenomena of self-acceleration and possibly auto-turbulization of cellular flames. Due to space limitation the effects of activation energy and the critical state for the onset of cellularity will not be discussed herein. Experiments were conducted using C3H8-air and H2-O2-N2 mixtures for their opposite influences of non-equidiffusivity. The additional system parameters varied were the chamber pressure (p) and the mixture composition including the equivalence ratio (phi). From a sequence of the flame images we can assess the propensity of cell formation, and determine the instantaneous flame radius (R), the flame propagation rate, the global stretch rate experienced by the flame, the critical flame radius at which cells start to grow, and the average cell size.

  7. Final Report

    SciTech Connect

    Robert D. Cess

    2008-12-05

    Paper number 1 addresses the fact that the procedure used in the Earth Radiation Budget Experiment for identifying the presence of clouds over snow/ice surfaces is known to have shortcomings, and this is corroborated through use of surface insolation measurements at the South Pole as an independent means of identifying clouds. These surface insolation measurements are then used to validate the more detailed cloud identification scheme used in the follow-up Clouds and the Earth's Radiant Energy System (CERES), and this validation is extended to the polar night through use of CERES measurements of the outgoing longwave radiation. General circulation models (GCMs) are highly sophisticated computer tools for modeling climate change, and they incorporate a large number of physical processes and variables. One of the most important challenges is to properly account for water vapor (clouds and humidity) in climate warming. In this Perspective, Cess discusses results reported in the same issue by Soden et al. in which water vapor feedback effects are tested by studying moistening trends in the upper troposphere. Satellite observations of atmospheric water vapor are found to agree well with moisture predictions generated by one of the key GCMs, showing that these feedback effects are being properly handled in the model, which eliminates a major potential source of uncertainty. Zhou and Cess [2001] developed an algorithm for retrieving surface downwelling longwave radiation (SDLW) based upon detailed studies using radiative transfer model calculations and surface radiometric measurements. Their algorithm linked clear sky SDLW with surface upwelling longwave flux and column precipitable water vapor. For cloudy sky cases, they used cloud liquid water path as an additional parameter to account for the effects of clouds. Despite the simplicity of their algorithm, it performed very well for most geographical regions except for those regions where the atmospheric conditions near

  8. Cellular basis for QT dispersion.

    PubMed

    Antzelevitch, C; Shimizu, W; Yan, G X; Sicouri, S

    1998-01-01

    The cellular basis for the dispersion of the QT interval recorded at the body surface is incompletely understood. Contributing to QT dispersion are heterogeneities of repolarization time in the three-dimensional structure of the ventricular myocardium, which are secondary to regional differences in action potential duration (APD) and activation time. While differences in APD occur along the apicobasal and anteroposterior axes in both epicardium and endocardium of many species, transitions are usually gradual. Recent studies have also demonstrated important APD gradients along the transmural axis. Because transmural heterogeneities in repolarization time are more abrupt than those recorded along the surfaces of the heart, they may represent a more onerous substrate for the development of arrhythmias, and their quantitation may provide a valuable tool for evaluation of arrhythmia risk. Our data, derived from the arterially perfused canine left ventricular wedge preparation, suggest that transmural gradients of voltage during repolarization contribute importantly to the inscription of the T wave. The start of the T wave is caused by a more rapid decline of the plateau, or phase 2 of the epicardial action potential, creating a voltage gradient across the wall. The gradient increases as the epicardial action potential continues to repolarize, reaching a maximum with full repolarization of epicardium; this juncture marks the peak of the T wave. The next region to repolarize is endocardium, giving rise to the initial descending limb of the upright T wave. The last region to repolarize is the M region, contributing to the final segment of the T wave. Full repolarization of the M region marks the end of the T wave. The time interval between the peak and the end of the T wave therefore represents the transmural dispersion of repolarization. Conditions known to augment QTc dispersion, including acquired long QT syndrome (class IA or III antiarrhythmics) lead to augmentation

  9. Geoengineering design parameters workshop

    SciTech Connect

    St. John, C.M. and Associates, Grand Junction, CO ); Kim, Kunsoo . Rockwell Hanford Operations)

    1985-12-12

    A one-day workshop on the subject of the geotechnical design parameters, in situ stress and rock mass strength, for a nuclear waste repository in basalt was held in Rapid City, South Dakota, on June 25, 1989. A panel comprised of five widely recognized experts in the field of rock mechanics, met to discuss the state of stress at the Hanford Site and the strength of a basalt rock mass. This report summarizes the discussions that took place and presents a set of final position statements developed collaboratively by the panel and the workshop moderator. The report concludes with a set of specific recommendations for future actions considered necessary to adequately define the in situ stress and the rock mass strength at the Hanford Site and to document the position of the Basalt Waste Isolation Project in respect to these two critical design parameters.

  10. Fracture mechanics of cellular glass

    SciTech Connect

    Zwissler, J.G.; Adams, M.A.

    1981-02-01

    Cellular glasses are prime candidate materials for the structural substrate of mirrored glass for solar concentrator reflecting panels. These materials are brittle, however, and susceptible to mechanical failure from slow crack growth caused by a stress corrosion mechanism. The results are detailed of one part of a program established to develop improved cellular glasses and to characterize the behavior of these and commercially available materials. Commercial and developmental cellular glasses were tested and analyzed using standard testing techniques and models developed from linear fracture mechanics. Two models describing the fracture behavior of these materials are developed. Slow crack growth behavior in cellular glass was found to be more complex than that encountered in dense glasses or ceramics. The crack velocity was found to be strongly dependent upon water vapor transport to the tip of the moving crack. The existence of a static fatigue limit was not conclusively established, however, it is speculated that slow crack growth behavior in Region I may be slower, by orders of magnitude, than that found in dense glasses.

  11. Cellular Automata and the Humanities.

    ERIC Educational Resources Information Center

    Gallo, Ernest

    1994-01-01

    The use of cellular automata to analyze several pre-Socratic hypotheses about the evolution of the physical world is discussed. These hypotheses combine characteristics of both rigorous and metaphoric language. Since the computer demands explicit instructions for each step in the evolution of the automaton, such models can reveal conceptual…

  12. 3D surface reconstruction and visualization of the Drosophila wing imaginal disc at cellular resolution

    NASA Astrophysics Data System (ADS)

    Bai, Linge; Widmann, Thomas; Jülicher, Frank; Dahmann, Christian; Breen, David

    2013-01-01

    Quantifying and visualizing the shape of developing biological tissues provide information about the morphogenetic processes in multicellular organisms. The size and shape of biological tissues depend on the number, size, shape, and arrangement of the constituting cells. To better understand the mechanisms that guide tissues into their final shape, it is important to investigate the cellular arrangement within tissues. Here we present a data processing pipeline to generate 3D volumetric surface models of epithelial tissues, as well as geometric descriptions of the tissues' apical cell cross-sections. The data processing pipeline includes image acquisition, editing, processing and analysis, 2D cell mesh generation, 3D contourbased surface reconstruction, cell mesh projection, followed by geometric calculations and color-based visualization of morphological parameters. In their first utilization we have applied these procedures to construct a 3D volumetric surface model at cellular resolution of the wing imaginal disc of Drosophila melanogaster. The ultimate goal of the reported effort is to produce tools for the creation of detailed 3D geometric models of the individual cells in epithelial tissues. To date, 3D volumetric surface models of the whole wing imaginal disc have been created, and the apicolateral cell boundaries have been identified, allowing for the calculation and visualization of cell parameters, e.g. apical cross-sectional area of cells. The calculation and visualization of morphological parameters show position-dependent patterns of cell shape in the wing imaginal disc. Our procedures should offer a general data processing pipeline for the construction of 3D volumetric surface models of a wide variety of epithelial tissues.

  13. Nonsynchronous updating in the multiverse of cellular automata.

    PubMed

    Reia, Sandro M; Kinouchi, Osame

    2015-04-01

    In this paper we study updating effects on cellular automata rule space. We consider a subset of 6144 order-3 automata from the space of 262144 bidimensional outer-totalistic rules. We compare synchronous to asynchronous and sequential updatings. Focusing on two automata, we discuss how update changes destroy typical structures of these rules. Besides, we show that the first-order phase transition in the multiverse of synchronous cellular automata, revealed with the use of a recently introduced control parameter, seems to be robust not only to changes in update schema but also to different initial densities.

  14. Light Weight Biomorphous Cellular Ceramics from Cellulose Templates

    NASA Technical Reports Server (NTRS)

    Singh, Mrityunjay; Yee, Bo-Moon; Gray, Hugh R. (Technical Monitor)

    2003-01-01

    Bimorphous ceramics are a new class of materials that can be fabricated from the cellulose templates derived from natural biopolymers. These biopolymers are abundantly available in nature and are produced by the photosynthesis process. The wood cellulose derived carbon templates have three- dimensional interconnectivity. A wide variety of non-oxide and oxide based ceramics have been fabricated by template conversion using infiltration and reaction-based processes. The cellular anatomy of the cellulose templates plays a key role in determining the processing parameters (pyrolysis, infiltration conditions, etc.) and resulting ceramic materials. The processing approach, microstructure, and mechanical properties of the biomorphous cellular ceramics (silicon carbide and oxide based) have been discussed.

  15. Nonsynchronous updating in the multiverse of cellular automata

    NASA Astrophysics Data System (ADS)

    Reia, Sandro M.; Kinouchi, Osame

    2015-04-01

    In this paper we study updating effects on cellular automata rule space. We consider a subset of 6144 order-3 automata from the space of 262144 bidimensional outer-totalistic rules. We compare synchronous to asynchronous and sequential updatings. Focusing on two automata, we discuss how update changes destroy typical structures of these rules. Besides, we show that the first-order phase transition in the multiverse of synchronous cellular automata, revealed with the use of a recently introduced control parameter, seems to be robust not only to changes in update schema but also to different initial densities.

  16. The 3-dimensional cellular automata for HIV infection

    NASA Astrophysics Data System (ADS)

    Mo, Youbin; Ren, Bin; Yang, Wencao; Shuai, Jianwei

    2014-04-01

    The HIV infection dynamics is discussed in detail with a 3-dimensional cellular automata model in this paper. The model can reproduce the three-phase development, i.e., the acute period, the asymptotic period and the AIDS period, observed in the HIV-infected patients in a clinic. We show that the 3D HIV model performs a better robustness on the model parameters than the 2D cellular automata. Furthermore, we reveal that the occurrence of a perpetual source to successively generate infectious waves to spread to the whole system drives the model from the asymptotic state to the AIDS state.

  17. Lightweight 3D cellular composites inspired by balsa.

    PubMed

    Malek, Sardar; Raney, Jordan R; Lewis, Jennifer A; Gibson, Lorna J

    2017-03-17

    Additive manufacturing technologies offer new ways to fabricate cellular materials with composite cell walls, mimicking the structure and mechanical properties of woods. However, materials limitations and a lack of design tools have confined the usefulness of 3D printed cellular materials. We develop new carbon fiber reinforced, epoxy inks for 3D printing which result in printed materials with longitudinal Young's modulus up to 57 GPa (exceeding the longitudinal modulus of wood cell wall material). To guide the design of hierarchical cellular materials, we developed a parameterized, multi-scale, finite element model. Computational homogenization based on finite element simulations at multiple length scales is employed to obtain the elastic properties of the material at multiple length scales. Parameters affecting the elastic response of cellular composites, such as the volume fraction, orientation distribution, and aspect ratio of fibers within the cell walls as well as the cell geometry and relative density are included in the model. To validate the model, experiments are conducted on both solid carbon fiber/epoxy composites and cellular structures made from them, showing excellent agreement with computational multi-scale model predictions, both at the cell-wall and at the cellular-structure levels. Using the model, cellular structures are designed and experimentally shown to achieve a specific stiffness nearly as high as that observed in balsa wood. The good agreement between the multi-scale model predictions and experimental data provides confidence in the practical utility of this model as a tool for designing novel 3D cellular composites with unprecedented specific elastic properties.

  18. Cellular immunity and lymphokine production during spaceflights

    NASA Technical Reports Server (NTRS)

    Konstantinova, I. V.; Sonnenfeld, G.; Lesniak, A. T.; Shaffar, L.; Mandel, A.; Rykova, M. P.; Antropova, E. N.; Ferrua, B.

    1991-01-01

    Results are presented on changes in cellular immunity and in the production of lymphokine in spacecrews during spaceflights. Measurements were carried out on blood samples collected from 50 cosmonauts before and after spaceflights of different duration, on board Salyut-6, Salyut-7, or Mir. Additional data were obtained from rats flown on board the Cosmos-1667 and Cosmos-1887 biosatellites. The parameters measured included the PHA responsiveness of T lymphocytes, the activity of T-helper cells and of nonspecific T suppressors, the activity of the so-called natural killer lymphocytes, the production of gamma-interferon, and the cell-surface markers. Results showed that the frequency and the extent of changes in the immunologic resistance of subjects depended on the duration of the flight. However, even after the most prolonged (365 days) spaceflight, the changes observed were mostly of a functional character with subsequent rapid return to normal.

  19. Cellular cardiomyoplasty: routes of cell delivery and retention.

    PubMed

    Al Kindi, Adil; Ge, Yin; Shum-Tim, Dominique; Chiu, Ray C-J

    2008-01-01

    Experimental and clinical studies have proven the feasibility of cellular cardiomyoplasty in treating the damaged myocardium following ischemic injury. Over the years, this field has exploded with different investigators trying different routes of cell delivery ranging from direct cell injection into the heart to peripheral intravenous delivery utilizing the various signaling mechanisms known. These different routes have resulted in a wide range of retention and engraftment of cells in the target tissues. In this review, we will explore the different modalities of cell delivery, the pros and cons of each route and the cellular retention and therapeutic efficacy of these routes. We will then look into the different theories that try to explain the observed retention and engraftment of cells in the target tissues. Finally, we will discuss various methods that can improve cellular retention and engraftment and hence better improvement in myocardial function.

  20. Cellular therapy in bone-tendon interface regeneration

    PubMed Central

    Rothrauff, Benjamin B; Tuan, Rocky S

    2014-01-01

    The intrasynovial bone-tendon interface is a gradual transition from soft tissue to bone, with two intervening zones of uncalcified and calcified fibrocartilage. Following injury, the native anatomy is not restored, resulting in inferior mechanical properties and an increased risk of re-injury. Recent in vivo studies provide evidence of improved healing when surgical repair of the bone-tendon interface is augmented with cells capable of undergoing chondrogenesis. In particular, cellular therapy in bone-tendon healing can promote fibrocartilage formation and associated improvements in mechanical properties. Despite these promising results in animal models, cellular therapy in human patients remains largely unexplored. This review highlights the development and structure-function relationship of normal bone-tendon insertions. The natural healing response to injury is discussed, with subsequent review of recent research on cellular approaches for improved healing. Finally, opportunities for translating in vivo findings into clinical practice are identified. PMID:24326955

  1. Comparison of the effects of metals on cellular injury and lipid peroxidation in isolated rat hepatocytes

    SciTech Connect

    Stacey, N.H.; Klaassen, C.D.

    1981-01-01

    Various mechanisms, including increases in lipid peroxidation, have been proposed to account for metal-induced cellular injury. By comparing several metals in the same cell population, it is possible to determine whether a correlation exists between ability to produce cell injury and ability to alter parameters pertaining to a particular mechanism. Of particular interest in this study was the relation between metal-induced cytotoxicity and increases in lipid peroxidation. The effects of Cr, Mn, Zn, Ni, Pb, Se, V, Fe, Cd, Hg, and Cu, at final concentrations of 1 to 1000 ..mu..M, on the viability of isolated hepatocytes were therefore examined by assessing the loss of intracellular K/sup +/ and aspartate aminotransferase (AST). Simultaneously, the ability of the metals to induce lipid peroxidation, as measured by an increase in thiobarbituric acid (TBA) reactants, was assessed. Hg and Cu required the lowest concentration to produce cellular injury, while Cd produced less dramatic changes in cell viability and Fe at 1000 ..mu..M produced only a small decrease in intracellular K/sup +/. The largest absolute increases in lipid peroxidation were found in the presence of V, followed by Fe and Hg, with Cd and Se causing the smallest increase in TBA reactants. These observations suggest that the lipid peroxidation associated with Cd and Hg is not necessarily responsible for the loss of cell viability induced by these two metals.

  2. Energetic costs of cellular computation.

    PubMed

    Mehta, Pankaj; Schwab, David J

    2012-10-30

    Cells often perform computations in order to respond to environmental cues. A simple example is the classic problem, first considered by Berg and Purcell, of determining the concentration of a chemical ligand in the surrounding media. On general theoretical grounds, it is expected that such computations require cells to consume energy. In particular, Landauer's principle states that energy must be consumed in order to erase the memory of past observations. Here, we explicitly calculate the energetic cost of steady-state computation of ligand concentration for a simple two-component cellular network that implements a noisy version of the Berg-Purcell strategy. We show that learning about external concentrations necessitates the breaking of detailed balance and consumption of energy, with greater learning requiring more energy. Our calculations suggest that the energetic costs of cellular computation may be an important constraint on networks designed to function in resource poor environments, such as the spore germination networks of bacteria.

  3. Energetic costs of cellular computation

    PubMed Central

    Mehta, Pankaj; Schwab, David J.

    2012-01-01

    Cells often perform computations in order to respond to environmental cues. A simple example is the classic problem, first considered by Berg and Purcell, of determining the concentration of a chemical ligand in the surrounding media. On general theoretical grounds, it is expected that such computations require cells to consume energy. In particular, Landauer’s principle states that energy must be consumed in order to erase the memory of past observations. Here, we explicitly calculate the energetic cost of steady-state computation of ligand concentration for a simple two-component cellular network that implements a noisy version of the Berg–Purcell strategy. We show that learning about external concentrations necessitates the breaking of detailed balance and consumption of energy, with greater learning requiring more energy. Our calculations suggest that the energetic costs of cellular computation may be an important constraint on networks designed to function in resource poor environments, such as the spore germination networks of bacteria. PMID:23045633

  4. Optofluidic Detection for Cellular Phenotyping

    PubMed Central

    Tung, Yi-Chung; Huang, Nien-Tsu; Oh, Bo-Ram; Patra, Bishnubrata; Pan, Chi-Chun; Qiu, Teng; Paul, K. Chu; Zhang, Wenjun; Kurabayashi, Katsuo

    2012-01-01

    Quantitative analysis of the output of processes and molecular interactions within a single cell is highly critical to the advancement of accurate disease screening and personalized medicine. Optical detection is one of the most broadly adapted measurement methods in biological and clinical assays and serves cellular phenotyping. Recently, microfluidics has obtained increasing attention due to several advantages, such as small sample and reagent volumes, very high throughput, and accurate flow control in the spatial and temporal domains. Optofluidics, which is the attempt to integrate optics with microfluidic, shows great promise to enable on-chip phenotypic measurements with high precision, sensitivity, specificity, and simplicity. This paper reviews the most recent developments of optofluidic technologies for cellular phenotyping optical detection. PMID:22854915

  5. Cellular solidification of transparent monotectics

    NASA Technical Reports Server (NTRS)

    Kaulker, W. F.

    1986-01-01

    Understanding how liquid phase particles are engulfed or pushed during freezing of a monotectic is addressed. The additional complication is that the solid-liquid interface is nonplanar due to constitutional undercooling. Some evidence of particle pushing where the particles are the liquid phase of the montectic was already observed. Cellular freezing of the succinonitrile-glycerol system also occurred. Only a few compositions were tested at that time. The starting materials were not especially pure so that cellular interface observed was likely due to the presence of unkown impurities, the major portion of which was water. Topics addressed include: the effort of modeling the particle pushing process using the computer, establishing an apparatus for the determination of phase diagrams, and the measurement of the temperature gradients with a specimen which will solidify on the temperature gradient microscope stage.

  6. Hox Targets and Cellular Functions

    PubMed Central

    Sánchez-Herrero, Ernesto

    2013-01-01

    Hox genes are a group of genes that specify structures along the anteroposterior axis in bilaterians. Although in many cases they do so by modifying a homologous structure with a different (or no) Hox input, there are also examples of Hox genes constructing new organs with no homology in other regions of the body. Hox genes determine structures though the regulation of targets implementing cellular functions and by coordinating cell behavior. The genetic organization to construct or modify a certain organ involves both a genetic cascade through intermediate transcription factors and a direct regulation of targets carrying out cellular functions. In this review I discuss new data from genome-wide techniques, as well as previous genetic and developmental information, to describe some examples of Hox regulation of different cell functions. I also discuss the organization of genetic cascades leading to the development of new organs, mainly using Drosophila melanogaster as the model to analyze Hox function. PMID:24490109

  7. Peroxisome Metabolism and Cellular Aging

    PubMed Central

    Titorenko, Vladimir I.; Terlecky, Stanley R.

    2010-01-01

    The essential role of peroxisomes in fatty acid oxidation, anaplerotic metabolism, and hydrogen peroxide turnover is well established. Recent findings suggest these and other related biochemical processes governed by the organelle may also play a critical role in regulating cellular aging. The goal of this review is to summarize and integrate into a model, the evidence that peroxisome metabolism actually helps define the replicative and chronological age of a eukaryotic cell. In this model, peroxisomal reactive oxygen species (ROS) are seen as altering organelle biogenesis and function, and eliciting changes in the dynamic communication networks that exist between peroxisomes and other cellular compartments. At low levels, peroxisomal ROS activate an anti-aging program in the cell; at concentrations beyond a specific threshold, a pro-aging course is triggered. PMID:21083858

  8. Xtoys: Cellular automata on xwindows

    SciTech Connect

    Creutz, M.

    1995-08-15

    Xtoys is a collection of xwindow programs for demonstrating simulations of various statistical models. Included are xising, for the two dimensional Ising model, xpotts, for the q-state Potts model, xautomalab, for a fairly general class of totalistic cellular automata, xsand, for the Bak-Tang-Wiesenfield model of self organized criticality, and xfires, a simple forest fire simulation. The programs should compile on any machine supporting xwindows.

  9. An Overview of Cellular Telecommunications

    DTIC Science & Technology

    1991-03-01

    Standard," Telephony, January 21, 1991. 142 33. Sklar , Bernard , Digital Communications, Prentice Hall, 1988. 34. Jordan, Edward C., Reference Data for...COSATI CODES 18. SUBJECT TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP Cellular radio; Digital radio...communications systems, and treats their history, theory and operation, applications, and limitations. Additionally, new experimental digital and micro

  10. Cellular Immune Mechanisms in Malaria.

    DTIC Science & Technology

    1980-08-31

    AD-A132 480 CELLULAR IMUNE MECHANISMS IN MALARIAIUI WASHINGTON I UNIV ST LOUIS 00 SCHOOL OF MEDICINE R P UACDERUOTT 31 AUG 8o 0AMI17-78-C-8012...lupus erythematosus (15). Subsequently, a variety of other disease states have been shown to be associated with an increased incidence of...lymphocytotoxic antibodies, including inflammatory bowel disease (16) and multiple sclerosis (17). We therefore also decided to investigate sera of adult Thai

  11. Glycosylation regulates prestin cellular activity.

    PubMed

    Rajagopalan, Lavanya; Organ-Darling, Louise E; Liu, Haiying; Davidson, Amy L; Raphael, Robert M; Brownell, William E; Pereira, Fred A

    2010-03-01

    Glycosylation is a common post-translational modification of proteins and is implicated in a variety of cellular functions including protein folding, degradation, sorting and trafficking, and membrane protein recycling. The membrane protein prestin is an essential component of the membrane-based motor driving electromotility changes (electromotility) in the outer hair cell (OHC), a central process in auditory transduction. Prestin was earlier identified to possess two N-glycosylation sites (N163, N166) that, when mutated, marginally affect prestin nonlinear capacitance (NLC) function in cultured cells. Here, we show that the double mutant prestin(NN163/166AA) is not glycosylated and shows the expected NLC properties in the untreated and cholesterol-depleted HEK 293 cell model. In addition, unlike WT prestin that readily forms oligomers, prestin(NN163/166AA) is enriched as monomers and more mobile in the plasma membrane, suggesting that oligomerization of prestin is dependent on glycosylation but is not essential for the generation of NLC in HEK 293 cells. However, in the presence of increased membrane cholesterol, unlike the hyperpolarizing shift in NLC seen with WT prestin, cells expressing prestin(NN163/166AA) exhibit a linear capacitance function. In an attempt to explain this finding, we discovered that both WT prestin and prestin(NN163/166AA) participate in cholesterol-dependent cellular trafficking. In contrast to WT prestin, prestin(NN163/166AA) shows a significant cholesterol-dependent decrease in cell-surface expression, which may explain the loss of NLC function. Based on our observations, we conclude that glycosylation regulates self-association and cellular trafficking of prestin(NN163/166AA). These observations are the first to implicate a regulatory role for cellular trafficking and sorting in prestin function. We speculate that the cholesterol regulation of prestin occurs through localization to and internalization from membrane microdomains by

  12. Innate cellular immunity and xenotransplantation

    PubMed Central

    Wang, Hui; Yang, Yong-Guang

    2012-01-01

    Purpose of review This review assesses the recent progress in xenograft rejection by innate immune responses, with a focus on innate cellular xenoreactivity. Recent findings Current literature was reviewed for new insights into the role of innate cellular immunity in xenograft rejection. Increasing evidence confirms that vigorous innate immune cell activation is accounted for by a combination of xenoantigen recognition by activating receptors, and incompatibility in inhibitory receptor-ligand interactions. Although both innate humoral and cellular xenoimmune responses are predominantly elicited by preformed and induced xenoreactive antibodies in nonhuman primates following porcine xenotransplantation, innate immune cells can also be activated by xenografts in the absence of antibodies. The latter antibody-independent response will likely persist in recipients even when adaptive xenoimmune responses are suppressed. In addition to xenograft rejection by recipient innate immune cells, phagocytic cells within liver xenografts are also deleterious to recipients by causing thrombocytopenia. Summary Strategies of overcoming innate immune responses are required for successful clinical xenotransplantation. In addition to developing better immunosuppressive and tolerance induction protocols, endeavors towards further genetic modifications of porcine source animals are ultimately important for successful clinical xenotransplantation. PMID:22262106

  13. A CRITERION PAPER ON PARAMETERS OF EDUCATION. FINAL REVISION.

    ERIC Educational Resources Information Center

    MEIERHENRY, W. C.

    THIS POSITION PAPER DEFINES ASPECTS OF INNOVATION IN EDUCATION. THE APPROPRIATENESS OF PLANNED CHANGE AND THE LEGITIMACY OF FUNCTION OF PLANNED CHANGE ARE DISCUSSED. PRIMARY ELEMENTS OF INNOVATION INCLUDE THE SUBSTITUTION OF ONE MATERIAL OR PROCESS FOR ANOTHER, THE RESTRUCTURING OF TEACHER ASSIGNMENTS, VALUE CHANGES WITH RESPECT TO TEACHING…

  14. Evaluation of fluid bed heat exchanger optimization parameters. Final report

    SciTech Connect

    Not Available

    1980-03-01

    Uncertainty in the relationship of specific bed material properties to gas-side heat transfer in fluidized beds has inhibited the search for optimum bed materials and has led to over-conservative assumptions in the design of fluid bed heat exchangers. An experimental program was carried out to isolate the effects of particle density, thermal conductivity, and heat capacitance upon fluid bed heat transfer. A total of 31 tests were run with 18 different bed material loads on 12 material types; particle size variations were tested on several material types. The conceptual design of a fluidized bed evaporator unit was completed for a diesel exhaust heat recovery system. The evaporator heat transfer surface area was substantially reduced while the physical dimensions of the unit increased. Despite the overall increase in unit size, the overall cost was reduced. A study of relative economics associated with bed material selection was conducted. For the fluidized bed evaporator, it was found that zircon sand was the best choice among materials tested in this program, and that the selection of bed material substantially influences the overall system costs. The optimized fluid bed heat exchanger has an estimated cost 19% below a fin augmented tubular heat exchanger; 31% below a commercial design fluid bed heat exchanger; and 50% below a conventional plain tube heat exchanger. The comparisons being made for a 9.6 x 10/sup 6/ Btu/h waste heat boiler. The fluidized bed approach potentially has other advantages such as resistance to fouling. It is recommended that a study be conducted to develop a systematic selection of bed materials for fluidized bed heat exchanger applications, based upon findings of the study reported herein.

  15. Passive cellular microrheology in developing fruit fly embryos

    NASA Astrophysics Data System (ADS)

    Crews, Sarah; Ma, Xiaoyan; Lawrence, Stacey; Hutson, M. Shane

    2012-02-01

    The development of fruit fly (Drosophila) embryos involves spatial and temporal regulation of cellular mechanical properties. These properties can be probed in vivo using laser hole drilling experiments; however, this technique only infers relative forces. Conversion to absolute forces requires measurement of cellular viscoelastic properties. Here, we use passive microrheology of fluorescently labeled cell membranes to measure the viscoelastic properties of amnioserosa cells. These dynamic epithelial cells play an important mechanical role during two developmental stages: germ band retraction and dorsal closure. Passive microrheology in this system is confounded by active contractions in the cytoskeleton. Thus, the fruit fly embryos are transiently anesthetized with CO2, halting active cellular movements, leaving only passive Brownian motion. The power spectra of these fluctuations are well fit by a Lorentzian -- as expected for Brownian motion -- and allow us to extract cellular viscoelastic parameters at different developmental stages. These measured parameters inform previous hole-drilling experiments and provide inputs for quantitative computational models of fruit fly embryonic development.

  16. Arrayed cellular environments for stem cells and regenerative medicine.

    PubMed

    Titmarsh, Drew M; Chen, Huaying; Wolvetang, Ernst J; Cooper-White, Justin J

    2013-02-01

    The behavior and composition of both multipotent and pluripotent stem cell populations are exquisitely controlled by a complex, spatiotemporally variable interplay of physico-chemical, extracellular matrix, cell-cell interaction, and soluble factor cues that collectively define the stem cell niche. The push for stem cell-based regenerative medicine models and therapies has fuelled demands for increasingly accurate cellular environmental control and enhanced experimental throughput, driving an evolution of cell culture platforms away from conventional culture formats toward integrated systems. Arrayed cellular environments typically provide a set of discrete experimental elements with variation of one or several classes of stimuli across elements of the array. These are based on high-content/high-throughput detection, small sample volumes, and multiplexing of environments to increase experimental parameter space, and can be used to address a range of biological processes at the cell population, single-cell, or subcellular level. Arrayed cellular environments have the capability to provide an unprecedented understanding of the molecular and cellular events that underlie expansion and specification of stem cell and therapeutic cell populations, and thus generate successful regenerative medicine outcomes. This review focuses on recent key developments of arrayed cellular environments and their contribution and potential in stem cells and regenerative medicine.

  17. Fluorescent sensing of fluoride in cellular system.

    PubMed

    Jiao, Yang; Zhu, Baocun; Chen, Jihua; Duan, Xiaohong

    2015-01-01

    Fluoride ions have the important roles in a lot of physiological activities related with biological and medical system, such as water fluoridation, caries treatment, and bone disease treatment. Great efforts have been made to develop new methods and strategies for F(-) detection in the past decades. Traditional methods for the detection of F(-) including ion chromatography, ion-selective electrodes, and spectroscopic techniques have the limitations in the biomedicine research. The fluorescent probes for F(-) are very promising that overcome some drawbacks of traditional fluoride detection methods. These probes exhibit high selectivity, high sensitivity as well as quick response to the detection of fluoride anions. The review commences with a brief description of photophysical mechanisms for fluorescent probes for fluoride, including photo induced electron transfer (PET), intramolecular charge transfer (ICT), fluorescence resonance energy transfer (FRET), and excited-state intramolecular proton transfer (ESIPT). Followed by a discussion about common dyes for fluorescent fluoride probes, such as anthracene, naphalimide, pyrene, BODIPY, fluorescein, rhodamine, resorufin, coumarin, cyanine, and near-infrared (NIR) dyes. We divide the fluorescent probes for fluoride in cellular application systems into nine groups, for example, type of hydrogen bonds, type of cleavage of Si-O bonds, type of Si-O bond cleavage and cylization reactions, etc. We also review the recent reported carriers in the delivery of fluorescent fluoride probes. Seventy-four typical fluorescent fluoride probes are listed and compared in detail, including quantum yield, reaction medium, excitation and emission wavelengths, linear detection range, selectivity for F(-), mechanism, and analytical applications. Finally, we discuss the future challenges of the application of fluorescent fluoride probes in cellular system and in vivo. We wish that more and more excellent fluorescent fluoride probes will be

  18. Statistical physical models of cellular motility

    NASA Astrophysics Data System (ADS)

    Banigan, Edward J.

    Cellular motility is required for a wide range of biological behaviors and functions, and the topic poses a number of interesting physical questions. In this work, we construct and analyze models of various aspects of cellular motility using tools and ideas from statistical physics. We begin with a Brownian dynamics model for actin-polymerization-driven motility, which is responsible for cell crawling and "rocketing" motility of pathogens. Within this model, we explore the robustness of self-diffusiophoresis, which is a general mechanism of motility. Using this mechanism, an object such as a cell catalyzes a reaction that generates a steady-state concentration gradient that propels the object in a particular direction. We then apply these ideas to a model for depolymerization-driven motility during bacterial chromosome segregation. We find that depolymerization and protein-protein binding interactions alone are sufficient to robustly pull a chromosome, even against large loads. Next, we investigate how forces and kinetics interact during eukaryotic mitosis with a many-microtubule model. Microtubules exert forces on chromosomes, but since individual microtubules grow and shrink in a force-dependent way, these forces lead to bistable collective microtubule dynamics, which provides a mechanism for chromosome oscillations and microtubule-based tension sensing. Finally, we explore kinematic aspects of cell motility in the context of the immune system. We develop quantitative methods for analyzing cell migration statistics collected during imaging experiments. We find that during chronic infection in the brain, T cells run and pause stochastically, following the statistics of a generalized Levy walk. These statistics may contribute to immune function by mimicking an evolutionarily conserved efficient search strategy. Additionally, we find that naive T cells migrating in lymph nodes also obey non-Gaussian statistics. Altogether, our work demonstrates how physical

  19. Fluorescent Sensing of Fluoride in Cellular System

    PubMed Central

    Jiao, Yang; Zhu, Baocun; Chen, Jihua; Duan, Xiaohong

    2015-01-01

    Fluoride ions have the important roles in a lot of physiological activities related with biological and medical system, such as water fluoridation, caries treatment, and bone disease treatment. Great efforts have been made to develop new methods and strategies for F- detection in the past decades. Traditional methods for the detection of F- including ion chromatography, ion-selective electrodes, and spectroscopic techniques have the limitations in the biomedicine research. The fluorescent probes for F- are very promising that overcome some drawbacks of traditional fluoride detection methods. These probes exhibit high selectivity, high sensitivity as well as quick response to the detection of fluoride anions. The review commences with a brief description of photophysical mechanisms for fluorescent probes for fluoride, including photo induced electron transfer (PET), intramolecular charge transfer (ICT), fluorescence resonance energy transfer (FRET), and excited-state intramolecular proton transfer (ESIPT). Followed by a discussion about common dyes for fluorescent fluoride probes, such as anthracene, naphalimide, pyrene, BODIPY, fluorescein, rhodamine, resorufin, coumarin, cyanine, and near-infrared (NIR) dyes. We divide the fluorescent probes for fluoride in cellular application systems into nine groups, for example, type of hydrogen bonds, type of cleavage of Si-O bonds, type of Si-O bond cleavage and cylization reactions, etc. We also review the recent reported carriers in the delivery of fluorescent fluoride probes. Seventy-four typical fluorescent fluoride probes are listed and compared in detail, including quantum yield, reaction medium, excitation and emission wavelengths, linear detection range, selectivity for F-, mechanism, and analytical applications. Finally, we discuss the future challenges of the application of fluorescent fluoride probes in cellular system and in vivo. We wish that more and more excellent fluorescent fluoride probes will be developed

  20. Primitive control of cellular metabolism

    NASA Technical Reports Server (NTRS)

    Mitz, M. A.

    1974-01-01

    It is pointed out that control substances must have existed from the earliest times in the evolution of life and that the same control mechanisms must exist today. The investigation reported is concerned with the concept that carbon dioxide is a primitive regulator of cell function. The effects of carbon dioxide on cellular materials are examined, taking into account questions of solubilization, dissociation, changes of charge, stabilization, structural changes, wettability, the exclusion of other gases, the activation of compounds, changes in plasticity, and changes in membrane permeability.

  1. Symmetry analysis of cellular automata

    NASA Astrophysics Data System (ADS)

    García-Morales, V.

    2013-01-01

    By means of B-calculus [V. García-Morales, Phys. Lett. A 376 (2012) 2645] a universal map for deterministic cellular automata (CAs) has been derived. The latter is shown here to be invariant upon certain transformations (global complementation, reflection and shift). When constructing CA rules in terms of rules of lower range a new symmetry, “invariance under construction” is uncovered. Modular arithmetic is also reformulated within B-calculus and a new symmetry of certain totalistic CA rules, which calculate the Pascal simplices modulo an integer number p, is then also uncovered.

  2. Cellular immune responses to HIV

    NASA Astrophysics Data System (ADS)

    McMichael, Andrew J.; Rowland-Jones, Sarah L.

    2001-04-01

    The cellular immune response to the human immunodeficiency virus, mediated by T lymphocytes, seems strong but fails to control the infection completely. In most virus infections, T cells either eliminate the virus or suppress it indefinitely as a harmless, persisting infection. But the human immunodeficiency virus undermines this control by infecting key immune cells, thereby impairing the response of both the infected CD4+ T cells and the uninfected CD8+ T cells. The failure of the latter to function efficiently facilitates the escape of virus from immune control and the collapse of the whole immune system.

  3. Reversibility of a Symmetric Linear Cellular Automata

    NASA Astrophysics Data System (ADS)

    Del Rey, A. Martín; Sánchez, G. Rodríguez

    The characterization of the size of the cellular space of a particular type of reversible symmetric linear cellular automata is introduced in this paper. Specifically, it is shown that those symmetric linear cellular with 2k + 1 cells, and whose transition matrix is a k-diagonal square band matrix with nonzero entries equal to 1 are reversible. Furthermore, in this case the inverse cellular automata are explicitly computed. Moreover, the reversibility condition is also studied for a general number of cells.

  4. Variable entangling in a quantum prisoner's dilemma cellular automaton

    NASA Astrophysics Data System (ADS)

    Alonso-Sanz, Ramón

    2015-01-01

    The effect of variable entangling on the dynamics of a spatial quantum formulation of the iterated prisoner's dilemma game is studied in this work. The game is played in the cellular automata manner, i.e., with local and synchronous interaction. The effect of spatial structure is assessed when allowing the players to adopt quantum and classical strategies, both in the two- and three-parameter strategy spaces.

  5. A quantum relativistic battle of the sexes cellular automaton

    NASA Astrophysics Data System (ADS)

    Alonso-Sanz, Ramón; Situ, Haozhen

    2017-02-01

    The effect of variable entangling on the dynamics of a spatial quantum relativistic formulation of the iterated battle of the sexes game is studied in this work. The game is played in the cellular automata manner, i.e., with local and synchronous interaction. The game is assessed in fair and unfair contests. Despite the full range of quantum parameters initially accessible, they promptly converge into fairly stable configurations, that often show rich spatial structures in simulations with no negligible entanglement.

  6. Protein accounting in the cellular economy.

    PubMed

    Vázquez-Laslop, Nora; Mankin, Alexander S

    2014-04-24

    Knowing the copy number of cellular proteins is critical for understanding cell physiology. By being able to measure the absolute synthesis rates of the majority of cellular proteins, Li et al. gain insights into key aspects of translation regulation and fundamental principles of cellular strategies to adjust protein synthesis according to the functional needs.

  7. Cellular dynamics and embryonic morphogenesis

    NASA Astrophysics Data System (ADS)

    Zallen, Jennifer

    2007-11-01

    The elongated body axis is a characteristic feature of many multicellular animals. Axis elongation occurs largely through cell rearrangements that are coordinated across a large cell population and driven by an asymmetric distribution of cytoskeletal and junctional proteins [1]. To visualize cellular dynamics during this process, we performed time-lapse confocal imaging of cell behavior in the Drosophila embryo. These studies revealed that rearranging cells display a steady increase in topological disorder that is accompanied by the formation of transient structures where 5-11 cells meet [2,3]. These multicellular rosettes form and resolve in a directional fashion to produce a local change in the aspect ratio of the cellular assembly, contributing to an overall change in tissue structure. We propose that higher-order rosette structures link local cell interactions to global tissue reorganization during morphogenesis. [1] J. Zallen and E. Wieschaus, Developmental Cell 6, 343 (2004). [2] J. Zallen and R. Zallen, J. Phys.: Condens. Matter 16, S5073 (2004). [3] J. Blankenship et al., Developmental Cell 11, 459 (2006).

  8. Cellular functions of the microprocessor.

    PubMed

    Macias, Sara; Cordiner, Ross A; Cáceres, Javier F

    2013-08-01

    The microprocessor is a complex comprising the RNase III enzyme Drosha and the double-stranded RNA-binding protein DGCR8 (DiGeorge syndrome critical region 8 gene) that catalyses the nuclear step of miRNA (microRNA) biogenesis. DGCR8 recognizes the RNA substrate, whereas Drosha functions as an endonuclease. Recent global analyses of microprocessor and Dicer proteins have suggested novel functions for these components independent of their role in miRNA biogenesis. A HITS-CLIP (high-throughput sequencing of RNA isolated by cross-linking immunoprecipitation) experiment designed to identify novel substrates of the microprocessor revealed that this complex binds and regulates a large variety of cellular RNAs. The microprocessor-mediated cleavage of several classes of RNAs not only regulates transcript levels, but also modulates alternative splicing events, independently of miRNA function. Importantly, DGCR8 can also associate with other nucleases, suggesting the existence of alternative DGCR8 complexes that may regulate the fate of a subset of cellular RNAs. The aim of the present review is to provide an overview of the diverse functional roles of the microprocessor.

  9. Cellular senescence and protein degradation

    PubMed Central

    Deschênes-Simard, Xavier; Lessard, Frédéric; Gaumont-Leclerc, Marie-France; Bardeesy, Nabeel; Ferbeyre, Gerardo

    2014-01-01

    Autophagy and the ubiquitin–proteasome pathway (UPP) are the major protein degradation systems in eukaryotic cells. Whereas the former mediate a bulk nonspecific degradation, the UPP allows a rapid degradation of specific proteins. Both systems have been shown to play a role in tumorigenesis, and the interest in developing therapeutic agents inhibiting protein degradation is steadily growing. However, emerging data point to a critical role for autophagy in cellular senescence, an established tumor suppressor mechanism. Recently, a selective protein degradation process mediated by the UPP was also shown to contribute to the senescence phenotype. This process is tightly regulated by E3 ubiquitin ligases, deubiquitinases, and several post-translational modifications of target proteins. Illustrating the complexity of UPP, more than 600 human genes have been shown to encode E3 ubiquitin ligases, a number which exceeds that of the protein kinases. Nevertheless, our knowledge of proteasome-dependent protein degradation as a regulated process in cellular contexts such as cancer and senescence remains very limited. Here we discuss the implications of protein degradation in senescence and attempt to relate this function to the protein degradation pattern observed in cancer cells. PMID:24866342

  10. Micromechanics of cellularized biopolymer networks

    PubMed Central

    Jones, Christopher A. R.; Cibula, Matthew; Feng, Jingchen; Krnacik, Emma A.; McIntyre, David H.; Levine, Herbert; Sun, Bo

    2015-01-01

    Collagen gels are widely used in experiments on cell mechanics because they mimic the extracellular matrix in physiological conditions. Collagen gels are often characterized by their bulk rheology; however, variations in the collagen fiber microstructure and cell adhesion forces cause the mechanical properties to be inhomogeneous at the cellular scale. We study the mechanics of type I collagen on the scale of tens to hundreds of microns by using holographic optical tweezers to apply pN forces to microparticles embedded in the collagen fiber network. We find that in response to optical forces, particle displacements are inhomogeneous, anisotropic, and asymmetric. Gels prepared at 21 °C and 37 °C show qualitative difference in their micromechanical characteristics. We also demonstrate that contracting cells remodel the micromechanics of their surrounding extracellular matrix in a strain- and distance-dependent manner. To further understand the micromechanics of cellularized extracellular matrix, we have constructed a computational model which reproduces the main experiment findings. PMID:26324923

  11. A Cellular GWAS Approach to Define Human Variation in Cellular Pathways Important to Inflammation

    PubMed Central

    Miller, Samuel I.; Chaudhary, Anu

    2016-01-01

    An understanding of common human diversity in innate immune pathways should be beneficial in understanding autoimmune diseases, susceptibility to infection, and choices of anti-inflammatory treatment. Such understanding could also result in definition of currently unknown components of human inflammation pathways. A cellular genome-wide association studies (GWAS) platform, termed Hi-HOST (High-throughput human in vitro susceptibility testing), was developed to assay in vitro cellular phenotypes of infection in genotyped lymphoblastoid cells from genetically diverse human populations. Hi-HOST allows for measurement of multiple host and pathogen parameters of infection/inflammation including: bacterial invasion and intracellular replication, host cell death, and cytokine production. Hi-HOST has been used to successfully define a significant portion of the heritable human diversity in inflammatory cell death in response to Salmonella typhimurium. It also led to the discovery of genetic variants important to protection against systemic inflammatory response syndrome (SIRS) and protection against death and bacteremia in individuals with SIRS. Our laboratory is currently using this platform to define human diversity in autophagy and the NLPR3 inflammasome pathways, and to define new components that can impact the expression of phenotypes related to these pathways. PMID:27128945

  12. Optimal flux patterns in cellular metabolic networks

    SciTech Connect

    Almaas, E

    2007-01-20

    The availability of whole-cell level metabolic networks of high quality has made it possible to develop a predictive understanding of bacterial metabolism. Using the optimization framework of flux balance analysis, I investigate metabolic response and activity patterns to variations in the availability of nutrient and chemical factors such as oxygen and ammonia by simulating 30,000 random cellular environments. The distribution of reaction fluxes is heavy-tailed for the bacteria H. pylori and E. coli, and the eukaryote S. cerevisiae. While the majority of flux balance investigations have relied on implementations of the simplex method, it is necessary to use interior-point optimization algorithms to adequately characterize the full range of activity patterns on metabolic networks. The interior-point activity pattern is bimodal for E. coli and S. cerevisiae, suggesting that most metabolic reaction are either in frequent use or are rarely active. The trimodal activity pattern of H. pylori indicates that a group of its metabolic reactions (20%) are active in approximately half of the simulated environments. Constructing the high-flux backbone of the network for every environment, there is a clear trend that the more frequently a reaction is active, the more likely it is a part of the backbone. Finally, I briefly discuss the predicted activity patterns of the central-carbon metabolic pathways for the sample of random environments.

  13. Cellular immune reactions in the lung.

    PubMed

    Hasenberg, Mike; Stegemann-Koniszewski, Sabine; Gunzer, Matthias

    2013-01-01

    The lung constantly interacts with the environment through thousands of liters of air that are inhaled daily. This continually transports toxic chemicals and particles or pathogenic microorganisms deep into the respiratory system, posing a challenge to physicochemical barriers and the local immune system. Thus, complex structures and mechanisms have evolved to recognize and fend off environmental dangers while at the same time allowing efficient gas exchange. Here we review our current knowledge regarding cellular mechanisms of the immune system in context with the highly specialized anatomical features of the airways and especially the alveolar compartment. The focus is on fungal and viral infections, merging anatomical aspects well known to pulmonologists with fundamental immunological concepts. We discuss the specialized morphological constraints of immune cells compressed under a continuous layer of the surfactant lining within alveoli as well as the importance of functional polarization of respiratory tract epithelia. Furthermore, we summarize the different types of innate and adaptive immune cells and their relative contribution to lung homeostasis with respect to localization. Finally, we provide a list of currently unresolved questions with high relevance for the field that might serve as food for thought regarding future research directions.

  14. Life and Times of a Cellular Bleb☆

    PubMed Central

    Charras, Guillaume T.; Coughlin, Margaret; Mitchison, Timothy J.; Mahadevan, L.

    2008-01-01

    Blebs are spherical cellular protrusions that occur in many physiological situations. Two distinct phases make up the life of a bleb, each of which have their own biology and physics: expansion, which lasts ∼30 s, and retraction, which lasts ∼2 min. We investigate these phases using optical microscopy and simple theoretical concepts, seeking information on blebbing itself, and on cytomechanics in general. We show that bleb nucleation depends on pressure, membrane-cortex adhesion energy, and membrane tension, and test this experimentally. Bleb growth occurs through a combination of bulk flow of lipids and delamination from the cell cortex via the formation and propagation of tears. In extreme cases, this can give rise to a traveling wave around the cell periphery, known as “circus movement.” When growth stalls, an actin cortex reforms under the bleb membrane, and retraction starts, driven by myosin-II. Using flicker spectroscopy, we find that retracting blebs are fivefold more rigid than expanding blebs, an increase entirely explained by the properties of the newly formed cortical actin mesh. Finally, using artificially nucleated blebs as pressure sensors, we show that cells rounded up in mitosis possess a substantial intracellular pressure. PMID:17921219

  15. Optimal flux patterns in cellular metabolic networks

    NASA Astrophysics Data System (ADS)

    Almaas, Eivind

    2007-06-01

    The availability of whole-cell-level metabolic networks of high quality has made it possible to develop a predictive understanding of bacterial metabolism. Using the optimization framework of flux balance analysis, I investigate the metabolic response and activity patterns to variations in the availability of nutrient and chemical factors such as oxygen and ammonia by simulating 30 000 random cellular environments. The distribution of reaction fluxes is heavy tailed for the bacteria H. pylori and E. coli, and the eukaryote S. cerevisiae. While the majority of flux balance investigations has relied on implementations of the simplex method, it is necessary to use interior-point optimization algorithms to adequately characterize the full range of activity patterns on metabolic networks. The interior-point activity pattern is bimodal for E. coli and S. cerevisiae, suggesting that most metabolic reactions are either in frequent use or are rarely active. The trimodal activity pattern of H. pylori indicates that a group of its metabolic reactions (20%) are active in approximately half of the simulated environments. Constructing the high-flux backbone of the network for every environment, there is a clear trend that the more frequently a reaction is active, the more likely it is a part of the backbone. Finally, I briefly discuss the predicted activity patterns of the central carbon metabolic pathways for the sample of random environments.

  16. Thermomechanical characterisation of cellular rubber

    NASA Astrophysics Data System (ADS)

    Seibert, H.; Scheffer, T.; Diebels, S.

    2016-09-01

    This contribution discusses an experimental possibility to characterise a cellular rubber in terms of the influence of multiaxiality, rate dependency under environmental temperature and its behaviour under hydrostatic pressure. In this context, a mixed open and closed cell rubber based on an ethylene propylene diene monomer is investigated exemplarily. The present article intends to give a general idea of the characterisation method and the considerable effects of this special type of material. The main focus lies on the experimental procedure and the used testing devices in combination with the analysis methods such as true three-dimensional digital image correlation. The structural compressibility is taken into account by an approach for a material model using the Theory of Porous Media with additional temperature dependence.

  17. Cellular ageing mechanisms in osteoarthritis.

    PubMed

    Sacitharan, P K; Vincent, T L

    2016-08-01

    Age is the strongest independent risk factor for the development of osteoarthritis (OA) and for many years this was assumed to be due to repetitive microtrauma of the joint surface over time, the so-called 'wear and tear' arthritis. As our understanding of OA pathogenesis has become more refined, it has changed our appreciation of the role of ageing on disease. Cartilage breakdown in disease is not a passive process but one involving induction and activation of specific matrix-degrading enzymes; chondrocytes are exquisitely sensitive to changes in the mechanical, inflammatory and metabolic environment of the joint; cartilage is continuously adapting to these changes by altering its matrix. Ageing influences all of these processes. In this review, we will discuss how ageing affects tissue structure, joint use and the cellular metabolism. We describe what is known about pathways implicated in ageing in other model systems and discuss the potential value of targeting these pathways in OA.

  18. Cellular immune mechanisms in myocarditis.

    PubMed

    Noutsias, M; Patil, V J; Maisch, B

    2012-12-01

    The introduction of immunohistological techniques enabled a substantially more reliable diagnosis of inflammatory cardiomyopathy (DCMi) in endomyocardial biopsies (EMB) compared to the histological Dallas criteria. Decisive progress has been made in the understanding of cellular immune mechanisms in DCMi using immunohistological techniques, which apart from the field of diagnosis refinement have had prognostic implications and an influence on the selection criteria of DCMi patients who will likely benefit from immunosuppressive treatment. Digital image analysis systems have been employed to standardize quantification of immunohistological EMB stainings. Quantification of T cell-related genes by a methodologically validated preamplified real-time RT-PCR revealed that the T cells are characterized by differential expression of Th1-, Treg-, and CTL-related markers, while no major role could be confirmed for Th17 cells. The reported virus-associated differential T cell receptor Vbeta dominance suggests an antiviral specificity of virus-induced T cell responses in human DCMi.

  19. Regulation of cellular chromatin state

    PubMed Central

    Mishra, Rakesh K; Dhawan, Jyotsna

    2010-01-01

    The identity and functionality of eukaryotic cells is defined not just by their genomic sequence which remains constant between cell types, but by their gene expression profiles governed by epigenetic mechanisms. Epigenetic controls maintain and change the chromatin state throughout development, as exemplified by the setting up of cellular memory for the regulation and maintenance of homeotic genes in proliferating progenitors during embryonic development. Higher order chromatin structure in reversibly arrested adult stem cells also involves epigenetic regulation and in this review we highlight common trends governing chromatin states, focusing on quiescence and differentiation during myogenesis. Together, these diverse developmental modules reveal the dynamic nature of chromatin regulation providing fresh insights into the role of epigenetic mechanisms in potentiating development and differentiation. PMID:20592864

  20. Cellular compartmentalization of secondary metabolism

    PubMed Central

    Kistler, H. Corby; Broz, Karen

    2015-01-01

    Fungal secondary metabolism is often considered apart from the essential housekeeping functions of the cell. However, there are clear links between fundamental cellular metabolism and the biochemical pathways leading to secondary metabolite synthesis. Besides utilizing key biochemical precursors shared with the most essential processes of the cell (e.g., amino acids, acetyl CoA, NADPH), enzymes for secondary metabolite synthesis are compartmentalized at conserved subcellular sites that position pathway enzymes to use these common biochemical precursors. Co-compartmentalization of secondary metabolism pathway enzymes also may function to channel precursors, promote pathway efficiency and sequester pathway intermediates and products from the rest of the cell. In this review we discuss the compartmentalization of three well-studied fungal secondary metabolite biosynthetic pathways for penicillin G, aflatoxin and deoxynivalenol, and summarize evidence used to infer subcellular localization. We also discuss how these metabolites potentially are trafficked within the cell and may be exported. PMID:25709603

  1. Zika Virus Induced Cellular Remodeling.

    PubMed

    Rossignol, Evan D; Peters, Kristen N; Connor, John H; Bullitt, Esther

    2017-03-20

    Zika virus (ZIKV) has been associated with morbidities such as Guillain-Barré, infant microcephaly, and ocular disease. The spread of this positive-sense, single-stranded RNA virus and its growing public health threat underscore gaps in our understanding of basic ZIKV virology. To advance knowledge of the virus replication cycle within mammalian cells, we use serial section three-dimensional electron tomography to demonstrate the widespread remodeling of intracellular membranes upon infection with ZIKV. We report extensive structural rearrangements of the endoplasmic reticulum and reveal stages of the ZIKV viral replication cycle. Structures associated with RNA genome replication and virus assembly are observed integrated within the endoplasmic reticulum, and we show viruses in transit through the Golgi apparatus for viral maturation, and subsequent cellular egress. This study characterizes in detail the three-dimensional ultrastructural organization of the ZIKV replication cycle stages. Our results show close adherence of the ZIKV replication cycle to the existing flavivirus replication paradigm.

  2. Sensing phosphatidylserine in cellular membranes.

    PubMed

    Kay, Jason G; Grinstein, Sergio

    2011-01-01

    Phosphatidylserine, a phospholipid with a negatively charged head-group, is an important constituent of eukaryotic cellular membranes. On the plasma membrane, rather than being evenly distributed, phosphatidylserine is found preferentially in the inner leaflet. Disruption of this asymmetry, leading to the appearance of phosphatidylserine on the surface of the cell, is known to play a central role in both apoptosis and blood clotting. Despite its importance, comparatively little is known about phosphatidylserine in cells: its precise subcellular localization, transmembrane topology and intracellular dynamics are poorly characterized. The recent development of new, genetically-encoded probes able to detect phosphatidylserine within live cells, however, is leading to a more in-depth understanding of the biology of this phospholipid. This review aims to give an overview of the current methods for phosphatidylserine detection within cells, and some of the recent realizations derived from their use.

  3. Pressure-actuated cellular structures.

    PubMed

    Pagitz, M; Lamacchia, E; Hol, J M A M

    2012-03-01

    Shape changing structures will play an important role in future engineering designs since rigid structures are usually only optimal for a small range of service conditions. Hence, a concept for reliable and energy-efficient morphing structures that possess a large strength to self-weight ratio would be widely applicable. We propose a novel concept for morphing structures that is inspired by the nastic movement of plants. The idea is to connect prismatic cells with tailored pentagonal and/or hexagonal cross sections such that the resulting cellular structure morphs into given target shapes for certain cell pressures. An efficient algorithm for computing equilibrium shapes as well as cross-sectional geometries is presented. The potential of this novel concept is demonstrated by several examples that range from a flagellum like propulsion device to a morphing aircraft wing.

  4. Cellular stress and RNA splicing.

    PubMed

    Biamonti, Giuseppe; Caceres, Javier F

    2009-03-01

    In response to physical and chemical stresses that affect protein folding and, thus, the execution of normal metabolic processes, cells activate gene-expression strategies aimed at increasing their chance of survival. One target of several stressing agents is pre-mRNA splicing, which is inhibited upon heat shock. Recently, the molecular basis of this splicing inhibition has begun to emerge. Interestingly, different mechanisms seem to be in place to block constitutive pre-mRNA splicing and to affect alternative splicing regulation. This could be important to modulate gene expression during recovery from stress. Thus, pre-mRNA splicing emerges as a central mechanism to integrate cellular and metabolic stresses into gene-expression profiles.

  5. Fundamental Limits to Cellular Sensing

    NASA Astrophysics Data System (ADS)

    ten Wolde, Pieter Rein; Becker, Nils B.; Ouldridge, Thomas E.; Mugler, Andrew

    2016-03-01

    In recent years experiments have demonstrated that living cells can measure low chemical concentrations with high precision, and much progress has been made in understanding what sets the fundamental limit to the precision of chemical sensing. Chemical concentration measurements start with the binding of ligand molecules to receptor proteins, which is an inherently noisy process, especially at low concentrations. The signaling networks that transmit the information on the ligand concentration from the receptors into the cell have to filter this receptor input noise as much as possible. These networks, however, are also intrinsically stochastic in nature, which means that they will also add noise to the transmitted signal. In this review, we will first discuss how the diffusive transport and binding of ligand to the receptor sets the receptor correlation time, which is the timescale over which fluctuations in the state of the receptor, arising from the stochastic receptor-ligand binding, decay. We then describe how downstream signaling pathways integrate these receptor-state fluctuations, and how the number of receptors, the receptor correlation time, and the effective integration time set by the downstream network, together impose a fundamental limit on the precision of sensing. We then discuss how cells can remove the receptor input noise while simultaneously suppressing the intrinsic noise in the signaling network. We describe why this mechanism of time integration requires three classes (groups) of resources—receptors and their integration time, readout molecules, energy—and how each resource class sets a fundamental sensing limit. We also briefly discuss the scheme of maximum-likelihood estimation, the role of receptor cooperativity, and how cellular copy protocols differ from canonical copy protocols typically considered in the computational literature, explaining why cellular sensing systems can never reach the Landauer limit on the optimal trade

  6. Role of cellular communication in the pathways of radiation-induced biological damage

    NASA Astrophysics Data System (ADS)

    Ballarini, Francesca; Facoetti, Angelica; Mariotti, Luca; Nano, Rosanna; Ottolenghi, Andrea

    During the last decade, a large number of experimental studies on the so-called "non-targeted effects", in particular bystander effects, outlined that cellular communication plays a signifi- cant role in the pathways leading to radiation-induced biological damage. This might imply a paradigm shift in (low-dose) radiobiology, according to which one has to consider the response of groups of cells behaving like a population rather than single cells behaving as individuals. Furthermore, bystander effects, which are observed both for lethal endpoints (e.g. clonogenic inactivation and apoptosis) and for non-lethal ones (e.g. mutations and neoplastic transformation), tend to show non-linear dose responses characterized by a sharp increase followed by a plateau. This might have significant consequences in terms of low-dose risk, which is generally calculated on the basis of the "Linear No Threshold" hypothesis. Although it is known that two types of cellular communication (i.e. via gap junctions and/or molecular messengers diffusing in the extra-cellular environment, such as cytokines) play a major role, it is of utmost importance to better understand the underlying mechanisms, and how such mechanisms can be modulated by ionizing radiation. Though the "final" goal is to elucidate the in vivo scenario, in the meanwhile also in vitro studies can provide useful insights. In the present paper we will discuss key issues on the mechanisms underlying non-targeted effects and, more generally, cell communication, with focus on candidate molecular signals. Theoretical models and simulation codes can be of help in elucidating such mechanisms. In this framework, we will present a model and Monte Carlo code, under development at the University of Pavia, simulating the release, diffusion and internalization of candidate signals (typically cytokines) travelling in the extra-cellular environment, both by unirradiated (i.e., control) cells and by irradiated cells. The focus will be on the

  7. A palette of fluorescent proteins optimized for diverse cellular environments

    PubMed Central

    Costantini, Lindsey M.; Baloban, Mikhail; Markwardt, Michele L.; Rizzo, Mark; Guo, Feng; Verkhusha, Vladislav V.; Snapp, Erik L.

    2015-01-01

    To perform quantitative live cell imaging, investigators require fluorescent reporters that accurately report protein localization and levels, while minimally perturbing the cell. Yet, within the biochemically distinct environments of cellular organelles, popular fluorescent proteins (FPs), including EGFP, can be unreliable for quantitative imaging, resulting in underestimation of protein levels and incorrect localization. Specifically, within the secretory pathway, significant populations of FPs misfold and fail to fluoresce due to non-native disulphide bond formation. Furthermore, transmembrane FP fusion constructs can disrupt organelle architecture due to oligomerizing tendencies of numerous common FPs. Here, we describe a powerful set of bright and inert FPs optimized for use in multiple cellular compartments, especially oxidizing environments and biological membranes. Also, we provide new insights into use of red FPs in the secretory pathway. Our monomeric "oxFPs" finally resolve long standing, underappreciated, and important problems of cell biology and should be useful for a number of applications. PMID:26158227

  8. Cell dipole behaviour revealed by ECM sub-cellular geometry

    NASA Astrophysics Data System (ADS)

    Mandal, Kalpana; Wang, Irène; Vitiello, Elisa; Orellana, Laura Andreina Chacòn; Balland, Martial

    2014-12-01

    Cells sense and respond to their mechanical environment by exerting forces on their surroundings. The way forces are modulated by extra-cellular matrix (ECM) properties plays a key role in tissue homoeostasis. Using highly resolved micropatterns that constrain cells into the same square envelope but vary the adhesive geometry, here we investigate how the adhesive micro-environment affects the architecture of actin cytoskeleton and the orientation of traction forces. Our data demonstrate that local adhesive changes can trigger orientational ordering of stress fibres throughout the cell, suggesting that cells are capable of integrating information on ECM geometry at the whole-cell level. Finally, we show that cells tend to generate highly polarized force pattern, that is, unidirectional pinching, in response to adequate adhesive conditions. Hence, the geometry of adhesive environment can induce cellular orientation, a process which may have significant implications for the formation and mechanical properties of tissues.

  9. Cellular Immune Mechanisms in Malaria.

    DTIC Science & Technology

    1979-08-31

    secondary to the fragmented red cells rather than causative of an autoimmune hemolytic process (25,27). Finally, increased levels of auto-antibodies directed...there is suppressed antibody production, reduced severity of autoimmune disease, and increased susceptibility to tumor viruses (25). Secondly, there is...the immunopathologic effect of antigen-antibody complexes causing nephrotic disease in young children with P. malariae (26,27). Thirdly, anemia due to

  10. Influence parameters of impact grinding mills

    NASA Technical Reports Server (NTRS)

    Hoeffl, K.; Husemann, K.; Goldacker, H.

    1984-01-01

    Significant parameters for impact grinding mills were investigated. Final particle size was used to evaluate grinding results. Adjustment of the parameters toward increased charge load results in improved efficiency; however, it was not possible to define a single, unified set to optimum grinding conditions.

  11. Protein Targeting and Transport as a Necessary Consequence of Increased Cellular Complexity

    PubMed Central

    Sommer, Maik S.; Schleiff, Enrico

    2014-01-01

    With increasing intracellular complexity, a new cell-biological problem that is the allocation of cytoplasmically synthesized proteins to their final destinations within the cell emerged. A special challenge is thereby the translocation of proteins into or across cellular membranes. The underlying mechanisms are only in parts well understood, but it can be assumed that the course of cellular evolution had a deep impact on the design of the required molecular machines. In this article, we aim to summarize the current knowledge and concepts of the evolutionary development of protein trafficking as a necessary premise and consequence of increased cellular complexity. PMID:25085907

  12. Cellular basis of gravity resistance in plants

    NASA Astrophysics Data System (ADS)

    Hoson, Takayuki; Matsumoto, Shouhei; Inui, Kenichi; Zhang, Yan; Soga, Kouichi; Wakabayashi, Kazuyuki; Hashimoto, Takashi

    Mechanical resistance to the gravitational force is a principal gravity response in plants distinct from gravitropism. In the final step of gravity resistance, plants increase the rigidity of their cell walls via modifications to the cell wall metabolism and apoplastic environment. We studied cellular events that are related to the cell wall changes under hypergravity conditions produced by centrifugation. Hypergravity induced reorientation of cortical microtubules from transverse to longitudinal directions in epidermal cells of stem organs. In Arabidopsis tubulin mutants, the percentage of cells with longitudinal microtubules was high even at 1 g, and it was further increased by hypergravity. Hypocotyls of tubulin mutants also showed either left-handed or right-handed helical growth at 1 g, and the degree of twisting phenotype was intensified under hypergravity conditions. The left-handed helical growth mutants had right-handed microtubule arrays, whereas the right-handed mutant had left-handed arrays. There was a close correlation between the alignment angle of epidermal cell files and the alignment of cortical microtubules. Gadolinium ions suppressed both the twisting phenotype and reorientation of microtubules in tubulin mutants. These results support the hypothesis that cortical microtubules play an es-sential role in maintenance of normal growth phenotype against the gravitational force, and suggest that mechanoreceptors are involved in modifications to morphology and orientation of microtubule arrays by hypergravity. Actin microfilaments, in addition to microtubules, may be involved in gravity resistance. The nucleus of epidermal cells of azuki bean epicotyls, which is present almost in the center of the cell at 1 g, was displaced to the cell bottom by increasing the magnitude of gravity. Cytochalasin D stimulated the sedimentation by hypergravity of the nu-cleus, suggesting that the positioning of the nucleus is regulated by actin microfilaments, which is

  13. Cellular phones: are they detrimental?

    PubMed

    Salama, Osama E; Abou El Naga, Randa M

    2004-01-01

    The issue of possible health effects of cellular phones is very much alive in the public's mind where the rapid increase in the number of the users of cell phones in the last decade has increased the exposure of people to the electromagnetic fields (EMFs). Health consequences of long term use of mobile phones are not known in detail but available data indicates the development of non specific annoying symptoms on acute exposure to mobile phone radiations. In an attempt to determine the prevalence of such cell phones associated health manifestations and the factors affecting their occurrence, a cross sectional study was conducted in five randomly selected faculties of Alexandria University. Where, 300 individuals including teaching staff, students and literate employee were equally allocated and randomly selected among the five faculties. Data about mobile phone's users and their medical history, their pattern of mobile usage and the possible deleterious health manifestations associated with cellular phone use was collected. The results revealed 68% prevalence of mobile phone usage, nearly three quarters of them (72.5%) were complainers of the health manifestations. They suffered from headache (43%), earache (38.3%), sense of fatigue (31.6%), sleep disturbance (29.5%), concentration difficulty (28.5%) and face burning sensation (19.2%). Both univariate and multivariate analysis were consistent in their findings. Symptomatic users were found to have significantly higher frequency of calls/day, longer call duration and longer total duration of mobile phone usage/day than non symptomatic users. For headache both call duration and frequency of calls/day were the significant predicting factors for its occurrence (chi2 = 18.208, p = 0.0001). For earache, in addition to call duration, the longer period of owning the mobile phone were significant predictors (chi2 = 16.996, p = 0.0002). Sense of fatigue was significantly affected by both call duration and age of the user

  14. Marine molluscs in environmental monitoring. I. Cellular and molecular responses

    NASA Astrophysics Data System (ADS)

    Bresler, Vladimir; Abelson, Avigdor; Fishelson, Lev; Feldstein, Tamar; Rosenfeld, Michael; Mokady, Ofer

    2003-10-01

    The study reported here is part of an ongoing effort to establish sensitive and reliable biomonitoring markers for probing the coastal marine environment. Here, we report comparative measurements of a range of histological, cellular and sub-cellular parameters in molluscs sampled in polluted and reference sites along the Mediterranean coast of Israel and in the northern tip of the Gulf of Aqaba, Red Sea. Available species enabled an examination of conditions in two environmental 'compartments': benthic (Donax trunculus) and intertidal (Brachidontes pharaonis, Patella caerulea) in the Mediterranean; pelagic (Pteria aegyptia) and intertidal (Cellana rota) in the Red Sea. The methodology used provides rapid results by combining specialized fluorescent probes and contact microscopy, by which all parameters are measured in unprocessed animal tissue. The research focused on three interconnected levels. First, antixenobiotic defence mechanisms aimed at keeping hazardous agents outside the cell. Paracellular permeability was 70-100% higher in polluted sites, and membrane pumps (MXRtr and SATOA) activity was up to 65% higher in polluted compared to reference sites. Second, intracellular defence mechanisms that act to minimize potential damage by agents having penetrated the first line of defence. Metallothionein expression and EROD activity were 160-520% higher in polluted sites, and lysosomal functional activity (as measured by neutral red accumulation) was 25-50% lower. Third, damage caused by agents not sufficiently eliminated by the above mechanisms (e.g. single-stranded DNA breaks, chromosome damage and other pathological alterations). At this level, the most striking differences were observed in the rate of micronuclei formation and DNA breaks (up to 150% and 400% higher in polluted sites, respectively). The different mollusc species used feature very similar trends between polluted and reference sites in all measured parameters. Concentrating on relatively basic

  15. Reference materials for cellular therapeutics.

    PubMed

    Bravery, Christopher A; French, Anna

    2014-09-01

    The development of cellular therapeutics (CTP) takes place over many years, and, where successful, the developer will anticipate the product to be in clinical use for decades. Successful demonstration of manufacturing and quality consistency is dependent on the use of complex analytical methods; thus, the risk of process and method drift over time is high. The use of reference materials (RM) is an established scientific principle and as such also a regulatory requirement. The various uses of RM in the context of CTP manufacturing and quality are discussed, along with why they are needed for living cell products and the analytical methods applied to them. Relatively few consensus RM exist that are suitable for even common methods used by CTP developers, such as flow cytometry. Others have also identified this need and made proposals; however, great care will be needed to ensure any consensus RM that result are fit for purpose. Such consensus RM probably will need to be applied to specific standardized methods, and the idea that a single RM can have wide applicability is challenged. Written standards, including standardized methods, together with appropriate measurement RM are probably the most appropriate way to define specific starting cell types. The characteristics of a specific CTP will to some degree deviate from those of the starting cells; consequently, a product RM remains the best solution where feasible. Each CTP developer must consider how and what types of RM should be used to ensure the reliability of their own analytical measurements.

  16. Cellular neuropathology of tuberous sclerosis.

    PubMed

    Huttenlocher, P R; Wollmann, R L

    1991-01-01

    The study of cerebral lesions of TSC by special histologic methods suggests that two populations of neurons and glia occur in TSC brains. One is a population of normally differentiated cells that form a normally constituted cortical plate. The other is a group of cells that are poorly differentiated, fail to organize into a normal cortical architecture, and form a variety of abnormal cellular aggregates in cortex and in subcortical locations. The proportion of these abnormal cells varies greatly from patient to patient. In some the central nervous system appears to be entirely spared. In others, only one or a few islands of dysplastic cells occur, whereas in still others a large number, perhaps even a majority, of neuroectodermal cells in the forebrain may be affected. The proportion of total cells that undergo abnormal differentiation apparently is an important factor relative to cortical function in TSC. At present we have no explanation for this marked heterogeneity in expression of the TSC gene or genes, and it remains one of the many unsolved mysteries of this illness.

  17. Electrostatic Tuning of Cellular Excitability

    PubMed Central

    Börjesson, Sara I.; Parkkari, Teija; Hammarström, Sven; Elinder, Fredrik

    2010-01-01

    Abstract Voltage-gated ion channels regulate the electric activity of excitable tissues, such as the heart and brain. Therefore, treatment for conditions of disturbed excitability is often based on drugs that target ion channels. In this study of a voltage-gated K channel, we propose what we believe to be a novel pharmacological mechanism for how to regulate channel activity. Charged lipophilic substances can tune channel opening, and consequently excitability, by an electrostatic interaction with the channel's voltage sensors. The direction of the effect depends on the charge of the substance. This was shown by three compounds sharing an arachidonyl backbone but bearing different charge: arachidonic acid, methyl arachidonate, and arachidonyl amine. Computer simulations of membrane excitability showed that small changes in the voltage dependence of Na and K channels have prominent impact on excitability and the tendency for repetitive firing. For instance, a shift in the voltage dependence of a K channel with −5 or +5 mV corresponds to a threefold increase or decrease in K channel density, respectively. We suggest that electrostatic tuning of ion channel activity constitutes a novel and powerful pharmacological approach with which to affect cellular excitability. PMID:20141752

  18. The origins of cellular life.

    PubMed

    Schrum, Jason P; Zhu, Ting F; Szostak, Jack W

    2010-09-01

    Understanding the origin of cellular life on Earth requires the discovery of plausible pathways for the transition from complex prebiotic chemistry to simple biology, defined as the emergence of chemical assemblies capable of Darwinian evolution. We have proposed that a simple primitive cell, or protocell, would consist of two key components: a protocell membrane that defines a spatially localized compartment, and an informational polymer that allows for the replication and inheritance of functional information. Recent studies of vesicles composed of fatty-acid membranes have shed considerable light on pathways for protocell growth and division, as well as means by which protocells could take up nutrients from their environment. Additional work with genetic polymers has provided insight into the potential for chemical genome replication and compatibility with membrane encapsulation. The integration of a dynamic fatty-acid compartment with robust, generalized genetic polymer replication would yield a laboratory model of a protocell with the potential for classical Darwinian biological evolution, and may help to evaluate potential pathways for the emergence of life on the early Earth. Here we discuss efforts to devise such an integrated protocell model.

  19. Autophagy: cellular and molecular mechanisms.

    PubMed

    Glick, Danielle; Barth, Sandra; Macleod, Kay F

    2010-05-01

    Autophagy is a self-degradative process that is important for balancing sources of energy at critical times in development and in response to nutrient stress. Autophagy also plays a housekeeping role in removing misfolded or aggregated proteins, clearing damaged organelles, such as mitochondria, endoplasmic reticulum and peroxisomes, as well as eliminating intracellular pathogens. Thus, autophagy is generally thought of as a survival mechanism, although its deregulation has been linked to non-apoptotic cell death. Autophagy can be either non-selective or selective in the removal of specific organelles, ribosomes and protein aggregates, although the mechanisms regulating aspects of selective autophagy are not fully worked out. In addition to elimination of intracellular aggregates and damaged organelles, autophagy promotes cellular senescence and cell surface antigen presentation, protects against genome instability and prevents necrosis, giving it a key role in preventing diseases such as cancer, neurodegeneration, cardiomyopathy, diabetes, liver disease, autoimmune diseases and infections. This review summarizes the most up-to-date findings on how autophagy is executed and regulated at the molecular level and how its disruption can lead to disease.

  20. Integration of mobile satellite and cellular systems

    NASA Technical Reports Server (NTRS)

    Drucker, Elliott H.; Estabrook, Polly; Pinck, Deborah; Ekroot, Laura

    1993-01-01

    By integrating the ground based infrastructure component of a mobile satellite system with the infrastructure systems of terrestrial 800 MHz cellular service providers, a seamless network of universal coverage can be established. Users equipped for both cellular and satellite service can take advantage of a number of features made possible by such integration, including seamless handoff and universal roaming. To provide maximum benefit at lowest posible cost, the means by which these systems are integrated must be carefully considered. Mobile satellite hub stations must be configured to efficiently interface with cellular Mobile Telephone Switching Offices (MTSO's), and cost effective mobile units that provide both cellular and satellite capability must be developed.

  1. The cellular memory disc of reprogrammed cells.

    PubMed

    Anjamrooz, Seyed Hadi

    2013-04-01

    The crucial facts underlying the low efficiency of cellular reprogramming are poorly understood. Cellular reprogramming occurs in nuclear transfer, induced pluripotent stem cell (iPSC) formation, cell fusion, and lineage-switching experiments. Despite these advances, there are three fundamental problems to be addressed: (1) the majority of cells cannot be reprogrammed, (2) the efficiency of reprogramming cells is usually low, and (3) the reprogrammed cells developed from a patient's own cells activate immune responses. These shortcomings present major obstacles for using reprogramming approaches in customised cell therapy. In this Perspective, the author synthesises past and present observations in the field of cellular reprogramming to propose a theoretical picture of the cellular memory disc. The current hypothesis is that all cells undergo an endogenous and exogenous holographic memorisation such that parts of the cellular memory dramatically decrease the efficiency of reprogramming cells, act like a barrier against reprogramming in the majority of cells, and activate immune responses. Accordingly, the focus of this review is mainly to describe the cellular memory disc (CMD). Based on the present theory, cellular memory includes three parts: a reprogramming-resistance memory (RRM), a switch-promoting memory (SPM) and a culture-induced memory (CIM). The cellular memory arises genetically, epigenetically and non-genetically and affects cellular behaviours. [corrected].

  2. Final Report to DOE

    SciTech Connect

    Ismail Gultepe

    2012-05-15

    This final report summarizes the accomplished goals and provide a list of the publications and presentations made during the project. The goals of the project were accomplished through the various publications submitted to Journals and presentations done at the DOE and international meetings and conferences. The 8 journal articles related to the goals of this project were accepted or submitted. The 23 presentations related to goals of the project were presented at the meetings. There were some minor changes regarding to project goals because of issues encountered during the analysis of the data. For example, a total water probe sensor mounted on the Convair-580 that can be used for defining mixed phase conditions and parameterization, had some problems to estimate magnitude of total water mass, and this resulted in issues providing an accurate parameterization for cloud fraction. Variability related aerosol number concentrations and their composition for direct and indirect effects were studied and published. Results were given to explain aerosol and ice microphysical effects on climate change studies. It is suggested that developed parameterizations should consider the variability in aerosol and ice parameters over the Arctic regions.

  3. Final Technical Report

    SciTech Connect

    Alexander Pigarov

    2012-06-05

    This is the final report for the Research Grant DE-FG02-08ER54989 'Edge Plasma Simulations in NSTX and CTF: Synergy of Lithium Coating, Non-Diffusive Anomalous Transport and Drifts'. The UCSD group including: A.Yu. Pigarov (PI), S.I. Krasheninnikov and R.D. Smirnov, was working on modeling of the impact of lithium coatings on edge plasma parameters in NSTX with the multi-species multi-fluid code UEDGE. The work was conducted in the following main areas: (i) improvements of UEDGE model for plasma-lithium interactions, (ii) understanding the physics of low-recycling divertor regime in NSTX caused by lithium pumping, (iii) study of synergistic effects with lithium coatings and non-diffusive ballooning-like cross-field transport, (iv) simulation of experimental multi-diagnostic data on edge plasma with lithium pumping in NSTX via self-consistent modeling of D-Li-C plasma with UEDGE, and (v) working-gas balance analysis. The accomplishments in these areas are given in the corresponding subsections in Section 2. Publications and presentations made under the Grant are listed in Section 3.

  4. Are aberrant phase transitions a driver of cellular aging?

    PubMed Central

    2016-01-01

    Why do cells age? Recent advances show that the cytoplasm is organized into many membrane‐less compartments via a process known as phase separation, which ensures spatiotemporal control over diffusion‐limited biochemical reactions. Although phase separation is a powerful mechanism to organize biochemical reactions, it comes with the trade‐off that it is extremely sensitive to changes in physical‐chemical parameters, such as protein concentration, pH, or cellular energy levels. Here, we highlight recent findings showing that age‐related neurodegenerative diseases are linked to aberrant phase transitions in neurons. We discuss how these aberrant phase transitions could be tied to a failure to maintain physiological physical‐chemical conditions. We generalize this idea to suggest that the process of cellular aging involves a progressive loss of the organization of phase‐separated compartments in the cytoplasm. PMID:27554449

  5. Controlling Cellular Endocytosis at the Nanoscale

    NASA Astrophysics Data System (ADS)

    Battaglia, Giuseppe

    2011-03-01

    , amphiphilic molecules, and hydrophilic molecules without affecting the viability of cells or even triggering inflammatory pathways. Finally we show how size, surface chemistry and surface topology of the vesicles affect their interaction with the cell membrane and hence their cellular uptake. References: C. Lo Presti, M. Massignani, T. Smart, H. Lomas, and G. Battaglia J. Mater. Chem. (2009) 19, 3576-3590 H. Lomas, I. Canton, S. MacNeil, J. Du, S.P. Armes, A.J. Ryan, A.L. Lewis and G. Battaglia Adv. Mater. (2007). 19, 4238-4243 M. Massignani, I. Canton, N. Patikarnmonthon, N. J. Warren, S. P. Armes, A. L. Lewis and G. Battaglia, Nature Prec., 2010, http://hdl.handle.net/10101/npre.2010.4427.1 M. Massignani, C. LoPresti, A. Blanazs, J. Madsen, S. P. Armes, A. L. Lewis and G. Battaglia Small, 2009, 5, 2424-2432. M. Massignani, T. Sun, A. Blanazs, V. Hearnden, I. Canton, P. Desphande, S. Armes, S. MacNeil, A. Lewis and G. Battaglia PLoS One, 2010, 5, e10459.

  6. Photovoltaic module parameters acquisition model

    NASA Astrophysics Data System (ADS)

    Cibira, Gabriel; Koščová, Marcela

    2014-09-01

    This paper presents basic procedures for photovoltaic (PV) module parameters acquisition using MATLAB and Simulink modelling. In first step, MATLAB and Simulink theoretical model are set to calculate I-V and P-V characteristics for PV module based on equivalent electrical circuit. Then, limited I-V data string is obtained from examined PV module using standard measurement equipment at standard irradiation and temperature conditions and stated into MATLAB data matrix as a reference model. Next, the theoretical model is optimized to keep-up with the reference model and to learn its basic parameters relations, over sparse data matrix. Finally, PV module parameters are deliverable for acquisition at different realistic irradiation, temperature conditions as well as series resistance. Besides of output power characteristics and efficiency calculation for PV module or system, proposed model validates computing statistical deviation compared to reference model.

  7. Modeling Integrated Cellular Machinery Using Hybrid Petri-Boolean Networks

    PubMed Central

    Berestovsky, Natalie; Zhou, Wanding; Nagrath, Deepak; Nakhleh, Luay

    2013-01-01

    The behavior and phenotypic changes of cells are governed by a cellular circuitry that represents a set of biochemical reactions. Based on biological functions, this circuitry is divided into three types of networks, each encoding for a major biological process: signal transduction, transcription regulation, and metabolism. This division has generally enabled taming computational complexity dealing with the entire system, allowed for using modeling techniques that are specific to each of the components, and achieved separation of the different time scales at which reactions in each of the three networks occur. Nonetheless, with this division comes loss of information and power needed to elucidate certain cellular phenomena. Within the cell, these three types of networks work in tandem, and each produces signals and/or substances that are used by the others to process information and operate normally. Therefore, computational techniques for modeling integrated cellular machinery are needed. In this work, we propose an integrated hybrid model (IHM) that combines Petri nets and Boolean networks to model integrated cellular networks. Coupled with a stochastic simulation mechanism, the model simulates the dynamics of the integrated network, and can be perturbed to generate testable hypotheses. Our model is qualitative and is mostly built upon knowledge from the literature and requires fine-tuning of very few parameters. We validated our model on two systems: the transcriptional regulation of glucose metabolism in human cells, and cellular osmoregulation in S. cerevisiae. The model produced results that are in very good agreement with experimental data, and produces valid hypotheses. The abstract nature of our model and the ease of its construction makes it a very good candidate for modeling integrated networks from qualitative data. The results it produces can guide the practitioner to zoom into components and interconnections and investigate them using such more

  8. Modeling integrated cellular machinery using hybrid Petri-Boolean networks.

    PubMed

    Berestovsky, Natalie; Zhou, Wanding; Nagrath, Deepak; Nakhleh, Luay

    2013-01-01

    The behavior and phenotypic changes of cells are governed by a cellular circuitry that represents a set of biochemical reactions. Based on biological functions, this circuitry is divided into three types of networks, each encoding for a major biological process: signal transduction, transcription regulation, and metabolism. This division has generally enabled taming computational complexity dealing with the entire system, allowed for using modeling techniques that are specific to each of the components, and achieved separation of the different time scales at which reactions in each of the three networks occur. Nonetheless, with this division comes loss of information and power needed to elucidate certain cellular phenomena. Within the cell, these three types of networks work in tandem, and each produces signals and/or substances that are used by the others to process information and operate normally. Therefore, computational techniques for modeling integrated cellular machinery are needed. In this work, we propose an integrated hybrid model (IHM) that combines Petri nets and Boolean networks to model integrated cellular networks. Coupled with a stochastic simulation mechanism, the model simulates the dynamics of the integrated network, and can be perturbed to generate testable hypotheses. Our model is qualitative and is mostly built upon knowledge from the literature and requires fine-tuning of very few parameters. We validated our model on two systems: the transcriptional regulation of glucose metabolism in human cells, and cellular osmoregulation in S. cerevisiae. The model produced results that are in very good agreement with experimental data, and produces valid hypotheses. The abstract nature of our model and the ease of its construction makes it a very good candidate for modeling integrated networks from qualitative data. The results it produces can guide the practitioner to zoom into components and interconnections and investigate them using such more

  9. Interplay of drug metabolizing enzymes with cellular transporters.

    PubMed

    Böhmdorfer, Michaela; Maier-Salamon, Alexandra; Riha, Juliane; Brenner, Stefan; Höferl, Martina; Jäger, Walter

    2014-11-01

    Many endogenous and xenobiotic substances and their metabolites are substrates for drug metabolizing enzymes and cellular transporters. These proteins may not only contribute to bioavailability of molecules but also to uptake into organs and, consequently, to overall elimination. The coordinated action of uptake transporters, metabolizing enzymes, and efflux pumps, therefore, is a precondition for detoxification and elimination of drugs. As the understanding of the underlying mechanisms is important to predict alterations in drug disposal, adverse drug reactions and, finally, drug-drug interactions, this review illustrates the interplay between selected uptake/efflux transporters and phase I/II metabolizing enzymes.

  10. GENERAL: A modified weighted probabilistic cellular automaton traffic flow model

    NASA Astrophysics Data System (ADS)

    Zhuang, Qian; Jia, Bin; Li, Xin-Gang

    2009-08-01

    This paper modifies the weighted probabilistic cellular automaton model (Li X L, Kuang H, Song T, et al 2008 Chin. Phys. B 17 2366) which considered a diversity of traffic behaviors under real traffic situations induced by various driving characters and habits. In the new model, the effects of the velocity at the last time step and drivers' desire for acceleration are taken into account. The fundamental diagram, spatial-temporal diagram, and the time series of one-minute data are analyzed. The results show that this model reproduces synchronized flow. Finally, it simulates the on-ramp system with the proposed model. Some characteristics including the phase diagram are studied.

  11. "Biomoléculas": cellular metabolism didactic software

    NASA Astrophysics Data System (ADS)

    Menghi, M. L.; Novella, L. P.; Siebenlist, M. R.

    2007-11-01

    "Biomoléculas" is a software that deals with topics such as the digestion, cellular metabolism and excretion of nutrients. It is a pleasant, simple and didactic guide, made by and for students. In this program, each biomolecule (carbohydrates, lipids and proteins) is accompanied until its degradation and assimilation by crossing and interrelating the different metabolic channels to finally show the destination of the different metabolites formed and the way in which these are excreted. It is used at present as a teaching-learning process tool by the chair of Physiology and Biophysics at the Facultad de Ingeniería - Universidad Nacional de Entre Ríos.

  12. A Cellular Automata Based Model for Simulating Surface Hydrological Processes in Catchments

    NASA Astrophysics Data System (ADS)

    Shao, Qi; Baumgartl, Thomas; Huang, Longbin; Weatherley, Dion

    2014-05-01

    The Runoff Model Based on Cellular Automata (RunCA) has been developed to simulate the surface hydrological processes at the catchment scale by integrating basic cellular automata (CA) rules with fundamental measureable hydraulic properties. In this model, a two-dimensional lattice composed of a series of rectangular cells was employed to cover the study area. Runoff production within each cell was simulated by determining its water depth based on the rainfall, interception, infiltration and the balance between inflows and outflows. Particularly different infiltration equations were incorporated to make the model applicable for both single rainfall event (short term simulation) and multiple rainfall events (long term simulation). The distribution of water flow among cells was determined by applying CA transition rules based on the improved minimization-of-difference algorithm and the calculated spatially and temporally varied flow velocities according to the Manning's equation. RunCA was tested and validated at two catchments (Pine Glen Basin and Snow Shoe Basin, USA) with data taken from literature. The predicted hydrographs agreed well with the measured results. Simulated flow maps also demonstrated the model capability in capturing both the spatial and temporal variations in the runoff process. Model sensitivity analysis results showed that the simulated hydrographs were mostly influenced by the input parameters that represent the final steady infiltration rate, as well as the model settings of time step and cell size. Compared to some conventional distributed hydrologic models that calculate the runoff routing process by solving complex continuity equations, this model integrates a novel method and is expected to be more computationally efficient as it is based on simple CA transition rules when determining the flow distribution.

  13. Cellular toxicity of nicotinamide metabolites.

    PubMed

    Rutkowski, Bolesław; Rutkowski, Przemysław; Słomińska, Ewa; Smolenski, Ryszard T; Swierczyński, Julian

    2012-01-01

    There are almost 100 different substances called uremic toxins. Nicotinamide derivatives are known as new family of uremic toxins. These uremic compounds play a role in an increased oxidative stress and disturbances in cellular repair processes by inhibiting poly (ADP-ribose) polymerase activity. New members of this family were discovered and described. Their toxic properties were a subject of recent studies. This study evaluated the concentration of 4-pyridone-3-carboxamid-1-β-ribonucleoside-triphosphate (4PYTP) and 4-pyridone-3-carboxamid-1-β-ribonucleoside-monophosphate (4PYMP) in erythrocytes of patients with chronic renal failure. Serum and red blood cells were collected from chronic renal failure patients on conservative treatment, those treated with hemodialysis, and at different times from those who underwent kidney transplantation. Healthy volunteers served as a control group. Nicotinamide metabolites were determined using liquid chromatography with mass spectrometry based on originally discovered and described method. Three novel compounds were described: 4-pyridone-3-carboxamid-1-β-ribonucleoside (4PYR), 4PYMP, and 4PYTP. 4PYR concentration was elevated in the serum, whereas 4PYMP and 4PYTP concentrations were augmented in erythrocytes of dialysis patients. Interestingly, concentrations of these compounds were less elevated during the treatment with erythropoietin-stimulating agents (ESAs). After successful kidney transplantation, concentrations of 4PYR and 4PYMP normalized according to the graft function, whereas that of 4PYTP was still elevated. During the incubation of erythrocytes in the presence of 4PYR, concentration of 4PYMP rose very rapidly while that of 4PYTP increased slowly. Therefore, we hypothesized that 4PYR, as a toxic compound, was actively absorbed by erythrocytes and metabolized to the 4PYMP and 4PYTP, which may interfere with function and life span of these cells.

  14. Molecular and cellular limits to somatosensory specificity

    PubMed Central

    Belmonte, Carlos; Viana, Félix

    2008-01-01

    impulse generation can also influence the gating of transducing channels, dramatically modifying their activation profile. Thus, we propose that the capacity exhibited by the different functional types of somatosensory receptor neurons to preferentially detect and encode specific stimuli into a discharge of nerve impulses, appears to result of a characteristic combinatorial expression of different ion channels in each neuronal type that finally determines their transduction and impulse firing properties. Transduction channels don't operate in isolation and their cellular context should also be taken into consideration to fully understand their function. Moreover, the inhomogeneous distribution of transduction and voltage-gated channels at soma, axonal branches and peripheral endings of primary sensory neurons influences the characteristics of the propagated impulse discharge that encodes the properties of the stimulus. Alteration of this concerted operation of ion channels in pathological conditions may underlie the changes in excitability accompanying peripheral sensory neuron injuries. PMID:18419827

  15. Oscillatory cellular patterns in three-dimensional directional solidification

    NASA Astrophysics Data System (ADS)

    Tourret, D.; Debierre, J.-M.; Song, Y.; Mota, F. L.; Bergeon, N.; Guérin, R.; Trivedi, R.; Billia, B.; Karma, A.

    2015-10-01

    We present a phase-field study of oscillatory breathing modes observed during the solidification of three-dimensional cellular arrays in microgravity. Directional solidification experiments conducted onboard the International Space Station have allowed us to observe spatially extended homogeneous arrays of cells and dendrites while minimizing the amount of gravity-induced convection in the liquid. In situ observations of transparent alloys have revealed the existence, over a narrow range of control parameters, of oscillations in cellular arrays with a period ranging from about 25 to 125 min. Cellular patterns are spatially disordered, and the oscillations of individual cells are spatiotemporally uncorrelated at long distance. However, in regions displaying short-range spatial ordering, groups of cells can synchronize into oscillatory breathing modes. Quantitative phase-field simulations show that the oscillatory behavior of cells in this regime is linked to a stability limit of the spacing in hexagonal cellular array structures. For relatively high cellular front undercooling (i.e., low growth velocity or high thermal gradient), a gap appears in the otherwise continuous range of stable array spacings. Close to this gap, a sustained oscillatory regime appears with a period that compares quantitatively well with experiment. For control parameters where this gap exists, oscillations typically occur for spacings at the edge of the gap. However, after a change of growth conditions, oscillations can also occur for nearby values of control parameters where this gap just closes and a continuous range of spacings exists. In addition, sustained oscillations at to the opening of this stable gap exhibit a slow periodic modulation of the phase-shift among cells with a slower period of several hours. While long-range coherence of breathing modes can be achieved in simulations for a perfect spatial arrangement of cells as initial condition, global disorder is observed in both

  16. Oscillatory cellular patterns in three-dimensional directional solidification

    DOE PAGES

    Tourret, D.; Debierre, J. -M.; Song, Y.; ...

    2015-09-11

    We present a phase-field study of oscillatory breathing modes observed during the solidification of three-dimensional cellular arrays in micro-gravity. Directional solidification experiments conducted onboard the International Space Station have allowed for the first time to observe spatially extended homogeneous arrays of cells and dendrites while minimizing the amount of gravity-induced convection in the liquid. In situ observations of transparent alloys have revealed the existence, over a narrow range of control parameters, of oscillations in cellular arrays with a period ranging from about 25 to 125 minutes. Cellular patterns are spatially disordered, and the oscillations of individual cells are spatiotemporally uncorrelatedmore » at long distance. However, in regions displaying short-range spatial ordering, groups of cells can synchronize into oscillatory breathing modes. Quantitative phase-field simulations show that the oscillatory behavior of cells in this regime is linked to a stability limit of the spacing in hexagonal cellular array structures. For relatively high cellular front undercooling (\\ie low growth velocity or high thermal gradient), a gap appears in the otherwise continuous range of stable array spacings. Close to this gap, a sustained oscillatory regime appears with a period that compares quantitatively well with experiment. For control parameters where this gap exist, oscillations typically occur for spacings at the edge of the gap. However, after a change of growth conditions, oscillations can also occur for nearby values of control parameters where this gap just closes and a continuous range of spacings exists. In addition, sustained oscillations at to the opening of this stable gap exhibit a slow periodic modulation of the phase-shift among cells with a slower period of several hours. While long-range coherence of breathing modes can be achieved in simulations for a perfect spatial arrangement of cells as initial condition, global

  17. Oscillatory cellular patterns in three-dimensional directional solidification

    SciTech Connect

    Tourret, D.; Debierre, J. -M.; Song, Y.; Mota, F. L.; Bergeon, N.; Guerin, R.; Trivedi, R.; Billia, B.; Karma, A.

    2015-09-11

    We present a phase-field study of oscillatory breathing modes observed during the solidification of three-dimensional cellular arrays in micro-gravity. Directional solidification experiments conducted onboard the International Space Station have allowed for the first time to observe spatially extended homogeneous arrays of cells and dendrites while minimizing the amount of gravity-induced convection in the liquid. In situ observations of transparent alloys have revealed the existence, over a narrow range of control parameters, of oscillations in cellular arrays with a period ranging from about 25 to 125 minutes. Cellular patterns are spatially disordered, and the oscillations of individual cells are spatiotemporally uncorrelated at long distance. However, in regions displaying short-range spatial ordering, groups of cells can synchronize into oscillatory breathing modes. Quantitative phase-field simulations show that the oscillatory behavior of cells in this regime is linked to a stability limit of the spacing in hexagonal cellular array structures. For relatively high cellular front undercooling (\\ie low growth velocity or high thermal gradient), a gap appears in the otherwise continuous range of stable array spacings. Close to this gap, a sustained oscillatory regime appears with a period that compares quantitatively well with experiment. For control parameters where this gap exist, oscillations typically occur for spacings at the edge of the gap. However, after a change of growth conditions, oscillations can also occur for nearby values of control parameters where this gap just closes and a continuous range of spacings exists. In addition, sustained oscillations at to the opening of this stable gap exhibit a slow periodic modulation of the phase-shift among cells with a slower period of several hours. While long-range coherence of breathing modes can be achieved in simulations for a perfect spatial arrangement of cells as initial condition, global disorder is

  18. Cellular Manufacturing Internet Performance Support System

    SciTech Connect

    Bohley, M.C.; Schwartz, M.E.

    1998-03-04

    The objective of this project was to develop an Internet-based electronic performance support system (EPSS) for cellular manufacturing providing hardware/software specifications, process descriptions, estimated cost savings, manufacturing simulations, training information, and service resources for government and industry users of Cincinnati Milacron machine tools and products. AlliedSignal Federal Manufacturing and Technologies (ASFM and T) used expertise in the areas of Internet design and multimedia creation to develop a performance support system (PSS) for the Internet with assistance from CM's subject matter experts from engineering, manufacturing, and technical support. Reference information was both created and re-purposed from other existing formats, then made available on the Internet. On-line references on cellular manufacturing operations include: definitions of cells and cellular manufacturing; illustrations on how cellular manufacturing improves part throughput, resource utilization, part quality, and manufacturing flexibility; illustrations on how cellular manufacturing reduces labor and overhead costs; identification of critical factors driving decisions toward cellular manufacturing; a method for identifying process improvement areas using cellular manufacturing; a method for customizing the size of cells for a specific site; a simulation for making a part using cellular manufacturing technology; and a glossary of terms and concepts.

  19. Wearable vital parameters monitoring system

    NASA Astrophysics Data System (ADS)

    Caramaliu, Radu Vadim; Vasile, Alexandru; Bacis, Irina

    2015-02-01

    The system we propose monitors body temperature, heart rate and beside this, it tracks if the person who wears it suffers a faint. It uses a digital temperature sensor, a pulse sensor and a gravitational acceleration sensor to monitor the eventual faint or small heights free falls. The system continuously tracks the GPS position when available and stores the last valid data. So, when measuring abnormal vital parameters the module will send an SMS, using the GSM cellular network , with the person's social security number, the last valid GPS position for that person, the heart rate, the body temperature and, where applicable, a valid fall alert or non-valid fall alert. Even though such systems exist, they contain only faint detection or heart rate detection. Usually there is a strong correlation between low/high heart rate and an eventual faint. Combining both features into one system results in a more reliable detection device.

  20. Transition from a planar interface to cellular and dendritic structures during rapid solidification processing

    NASA Technical Reports Server (NTRS)

    Laxmanan, V.

    1986-01-01

    The development of theoretical models which characterize the planar-cellular and cell-dendrite transitions is described. The transitions are analyzed in terms of the Chalmers number, the solute Peclet number, and the tip stability parameter, which correlate microstructural features and processing conditions. The planar-cellular transition is examined using the constitutional supercooling theory of Chalmers et al., (1953) and it is observed that the Chalmers number is between 0 and 1 during dendritic and cellular growth. Analysis of cell-dendrite transition data reveal that the transition occurs when the solute Peclet number goes through a minimum, the primary arm spacings go through a maximum, and the Chalmers number is equal to 1/2. The relation between the tip stability parameter and the solute Peclet number is investigated and it is noted that the tip stability parameter is useful for studying dendritic growth in alloys.

  1. The mammary cellular hierarchy and breast cancer.

    PubMed

    Oakes, Samantha R; Gallego-Ortega, David; Ormandy, Christopher J

    2014-11-01

    Advances in the study of hematopoietic cell maturation have paved the way to a deeper understanding the stem and progenitor cellular hierarchy in the mammary gland. The mammary epithelium, unlike the hematopoietic cellular hierarchy, sits in a complex niche where communication between epithelial cells and signals from the systemic hormonal milieu, as well as from extra-cellular matrix, influence cell fate decisions and contribute to tissue homeostasis. We review the discovery, definition and regulation of the mammary cellular hierarchy and we describe the development of the concepts that have guided our investigations. We outline recent advances in in vivo lineage tracing that is now challenging many of our assumptions regarding the behavior of mammary stem cells, and we show how understanding these cellular lineages has altered our view of breast cancer.

  2. Final Technical Report

    SciTech Connect

    Schuur, Edward; Luo, Yiqi

    2016-12-01

    This final grant report is a continuation of the final grant report submitted for DE-SC0006982 as the Principle Investigator (Schuur) relocated from the University of Florida to Northern Arizona University. This report summarizes the original project goals, as well as includes new project activities that were completed in the final period of the project.

  3. Study of contact angle hysteresis using the Cellular Potts Model.

    PubMed

    Mortazavi, Vahid; D'Souza, Roshan M; Nosonovsky, Michael

    2013-02-28

    We use the Cellular Potts Model (CPM) to study the contact angle (CA) hysteresis in multiphase (solid-liquid-vapour) systems. We simulate a droplet over the tilted patterned surface, and a bubble placed under the surface immersed in liquid. The difference between bubbles and droplets was discussed through their CA hysteresis. Dependency of CA hysteresis on the surface structure and other parameters was also investigated. This analysis allows decoupling of the 1D (pinning of the triple line) and 2D (adhesion hysteresis in the contact area) effects and provides new insight into the nature of CA hysteresis.

  4. Cellular track model for study of heavy ion beams

    NASA Technical Reports Server (NTRS)

    Shinn, Judy L.; Katz, Robert; Cucinotta, Francis A.; Wilson, John W.; Ngo, Duc M.

    1993-01-01

    Track theory is combined with a realistic model of a heavy ion beam to study the effects of nuclear fragmentation on cell survival and biological effectiveness. The effects of secondary reaction products are studied as a function of depth in a water column. Good agreement is found with experimental results for the survival of human T-l cells exposed to monoenergetic carbon, neon, and argon beams under aerobic and hypoxia conditions. The present calculation, which includes the effect of target fragmentation, is a significant improvement over an earlier calculation because of the use of a vastly improved beam model with no change in the track theory or cellular response parameters.

  5. Markers of cellular senescence. Telomere shortening as a marker of cellular senescence

    PubMed Central

    2016-01-01

    The cellular senescence definition comes to the fact of cells irreversible proliferation disability. Besides the cell cycle arrest, senescent cells go through some morphological, biochemical, and functional changes which are the signs of cellular senescence. The senescent cells (including replicative senescence and stress-induced premature senescence) of all the tissues look alike. They are metabolically active and possess the set of characteristics in vitro and in vivo, which are known as biomarkers of aging and cellular senescence. Among biomarkers of cellular senescence telomere shortening is a rather elegant frequently used biomarker. Validity of telomere shortening as a marker for cellular senescence is based on theoretical and experimental data. PMID:26805432

  6. Markers of cellular senescence. Telomere shortening as a marker of cellular senescence.

    PubMed

    Bernadotte, Alexandra; Mikhelson, Victor M; Spivak, Irina M

    2016-01-01

    The cellular senescence definition comes to the fact of cells irreversible proliferation disability. Besides the cell cycle arrest, senescent cells go through some morphological, biochemical, and functional changes which are the signs of cellular senescence. The senescent cells (including replicative senescence and stress-induced premature senescence) of all the tissues look alike. They are metabolically active and possess the set of characteristics in vitro and in vivo, which are known as biomarkers of aging and cellular senescence. Among biomarkers of cellular senescence telomere shortening is a rather elegant frequently used biomarker. Validity of telomere shortening as a marker for cellular senescence is based on theoretical and experimental data.

  7. Final Technical Report

    SciTech Connect

    Aristos Aristidou Natureworks); Robert Kean; Tom Schechinger; Stuart Birrell; Jill Euken

    2007-10-01

    /storage/transportation equipment and the processor would build and operate the plant. Pilot fermentation studies demonstrated dramatic improvements in yields and rates with optimization of batch fermentor parameters. Demonstrated yields and rates are approaching those necessary for profitable commercial operation for production of ethanol or lactic acid. The ability of the biocatalyst to adapt to biomass hydrolysate (both biomass sugars and toxins in the hydrolysate) was demonstrated and points towards ultimate successful commercialization of the technology. However, some of this work will need to be repeated and possibly extended to adapt the final selected biocatalyst for the specific commercial hydrolysate composition. The path from corn stover in the farm field to final products, involves a number of steps. Each of these steps has options, problems, and uncertainties; thus creating a very complex multidimensional obstacle to successful commercial development. Through the tasks of this project, the technical and commercial uncertainties of many of these steps have been addressed; thus providing for a clearer understanding of paths forward and commercial viability of a corn stover-based biorefinery.

  8. Cellular and molecular neuronal plasticity.

    PubMed

    Griesbach, Grace S; Hovda, David A

    2015-01-01

    The brain has the capability to adapt to function when tissue is compromised. This capability of adaptation paves the road to recovery and allows for rehabilitation after a traumatic brain injury (TBI). This chapter addresses neuroplasticity within the context of TBI. Here neuroplasticity is defined as changes in neuronal structure and function, including synaptic changes as well as modifications in neural pathways. First, the influence of TBI pathology on neuroplasticity is addressed. Here, proteins that are important in neuroplasticity are introduced and a description given of how these are affected in a temporal and severity-dependent manner. Secondly, given that we are becoming increasingly aware that the brain's response to injury is highly influenced by the environmental milieu, the manner in which behavioral manipulations have an effect on TBI-associated neuroplasticity is addressed. A description is given of how specific environmental qualities may facilitate or hinder neuroplasticity. Finally, the long-term effects of neuroplasticity and the relevance it has to rehabilitation are described.

  9. Open boundaries in a cellular automaton model for traffic flow with metastable states.

    PubMed

    Barlovic, Robert; Huisinga, Torsten; Schadschneider, Andreas; Schreckenberg, Michael

    2002-10-01

    The effects of open boundaries in the velocity-dependent randomization (VDR) model, a modified version of the well-known Nagel-Schreckenberg (NaSch) cellular automaton model for traffic flow, are investigated. In contrast to the NaSch model, the VDR model exhibits metastable states and phase separation in a certain density regime. A proper insertion strategy allows us to investigate the whole spectrum of possible system states and the structure of the phase diagram by Monte Carlo simulations. We observe an interesting microscopic structure of the jammed phases, which is different from the one of the NaSch model. For finite systems, the existence of high flow states in a certain parameter regime leads to a special structure of the fundamental diagram measured in the open system. Apart from that, the results are in agreement with an extremal principle for the flow, which has been introduced for models with a unique flow-density relation. Finally, we discuss the application of our findings for a systematic flow optimization. Here some surprising results are obtained, e.g., a restriction of the inflow can lead to an improvement of the total flow through a bottleneck.

  10. Cell-to-cell communication in guided bone regeneration: molecular and cellular mechanisms.

    PubMed

    Gruber, Reinhard; Stadlinger, Bernd; Terheyden, Hendrik

    2016-08-23

    This overview provides insights into the molecular and cellular mechanisms involved in guided bone regeneration, in particular focusing on aspects presented in the 3D movie, Cell-To-Cell Communication in Guided Bone Regeneration. The information presented here is based almost exclusively on genetic mouse models in which single genes can be deleted or overexpressed, even in a specific cell type. This information needs to be extrapolated to humans and related to aspects relevant to graft consolidation under the clinical parameters of guided bone regeneration. The overview follows the ground tenor of the Cell-To-Cell Communication series and focuses on aspects of cell-to-cell communication in bone regeneration and guided bone regeneration. Here, we discuss (1) the role of inflammation during bone regeneration, including (2) the importance of the fibrin matrix, and (3) the pleiotropic functions of macrophages. We highlight (4) the origin of bone-forming osteoblasts and bone-resorbing osteoclasts as well as (5) what causes a progenitor cell to mature into an effector cell. (6) We touch on the complex bone adaptation and maintenance after graft consolidation and (7) how osteocytes control this process. Finally, we speculate on (8) how barrier membranes and the augmentation material can modulate graft consolidation.

  11. Redefining solubility parameters: the partial solvation parameters.

    PubMed

    Panayiotou, Costas

    2012-03-21

    The present work reconsiders a classical and universally accepted concept of physical chemistry, the solubility parameter. Based on the insight derived from modern quantum chemical calculations, a new definition of solubility parameter is proposed, which overcomes some of the inherent restrictions of the original definition and expands its range of applications. The original single solubility parameter is replaced by four partial solvation parameters reflecting the dispersion, the polar, the acidic and the basic character of the chemical compounds as expressed either in their pure state or in mixtures. Simple rules are adopted for the definition and calculation of these four parameters and their values are tabulated for a variety of common substances. In contrast, however, to the well known Hansen solubility parameters, their design and evaluation does not rely exclusively on the basic rule of "similarity matching" for solubility but it makes also use of the other basic rule of compatibility, namely, the rule of "complementarity matching". This complementarity matching becomes particularly operational with the sound definition of the acidic and basic components of the solvation parameter based on the third σ-moments of the screening charge distributions of the quantum mechanics-based COSMO-RS theory. The new definitions are made in a simple and straightforward manner, thus, preserving the strength and appeal of solubility parameter stemming from its simplicity. The new predictive method has been applied to a variety of solubility data for systems of pharmaceuticals and polymers. The results from quantum mechanics calculations are critically compared with the results from Abraham's acid/base descriptors.

  12. Passive Noise Filtering by Cellular Compartmentalization.

    PubMed

    Stoeger, Thomas; Battich, Nico; Pelkmans, Lucas

    2016-03-10

    Chemical reactions contain an inherent element of randomness, which presents itself as noise that interferes with cellular processes and communication. Here we discuss the ability of the spatial partitioning of molecular systems to filter and, thus, remove noise, while preserving regulated and predictable differences between single living cells. In contrast to active noise filtering by network motifs, cellular compartmentalization is highly effective and easily scales to numerous systems without requiring a substantial usage of cellular energy. We will use passive noise filtering by the eukaryotic cell nucleus as an example of how this increases predictability of transcriptional output, with possible implications for the evolution of complex multicellularity.

  13. Regulation of cellular identity in cancer

    PubMed Central

    Roy, Nilotpal; Hebrok, Matthias

    2015-01-01

    Summary Neoplastic transformation requires changes in cellular identity. Emerging evidence increasingly points to cellular reprogramming, a process during which fully differentiated and functional cells lose aspects of their identity while gaining progenitor characteristics, as a critical early step during cancer initiation. This cell identity crisis persists even at the malignant stage in certain cancers, suggesting that reactivation of progenitor functions supports tumorigenicity. Here, we review recent findings that establish the essential role of cellular reprogramming during neoplastic transformation and the major players involved in it with a special emphasis on pancreatic cancer. PMID:26702828

  14. Cellular and molecular mechanisms in kidney fibrosis

    PubMed Central

    Duffield, Jeremy S.

    2014-01-01

    Fibrosis is a characteristic feature of all forms of chronic kidney disease. Deposition of pathological matrix in the interstitial space and within the walls of glomerular capillaries as well as the cellular processes resulting in this deposition are increasingly recognized as important factors amplifying kidney injury and accelerating nephron demise. Recent insights into the cellular and molecular mechanisms of fibrogenesis herald the promise of new therapies to slow kidney disease progression. This review focuses on new findings that enhance understanding of cellular and molecular mechanisms of fibrosis, the characteristics of myofibroblasts, their progenitors, and molecular pathways regulating both fibrogenesis and its resolution. PMID:24892703

  15. Cellular solidification in a monotectic system

    NASA Technical Reports Server (NTRS)

    Kaukler, W. F.; Curreri, P. A.

    1987-01-01

    Succinonitrile-glycerol, SN-G, transparent organic monotectic alloy is studied with particular attention to cellular growth. The phase diagram is determined, near the monotectic composition, with greater accuracy than previous studies. A solidification interface stability diagram is determined for planar growth. The planar-to-cellular transition is compared to predictions from the Burton, Primm, Schlichter theory. A new technique to determine the solute segregation by Fourier transform infrared spectroscopy is developed. Proposed models that involve the cellular interface for alignment of monotectic second-phase spheres or rods are compared with observations.

  16. Exploring the Cellular Accumulation of Metal Complexes

    PubMed Central

    Puckett, Cindy A.; Ernst, Russell J.; Barton, Jacqueline K.

    2010-01-01

    Transition metal complexes offer great potential as diagnostic and therapeutic agents, and a growing number of biological applications have been explored. To be effective, these complexes must reach their intended target inside the cell. Here we review the cellular accumulation of metal complexes, including their uptake, localization, and efflux. Metal complexes are taken up inside cells through various mechanisms, including passive diffusion and entry through organic and metal transporters. Emphasis is placed on the methods used to examine cellular accumulation, to identify the mechanism(s) of uptake, and to monitor possible efflux. Conjugation strategies that have been employed to improve the cellular uptake characteristics of metal complexes are also described. PMID:20104335

  17. Short Communication: High Cellular Iron Levels Are Associated with Increased HIV Infection and Replication

    PubMed Central

    Chang, Hsiang-Chun; Bayeva, Marina; Taiwo, Babafemi; Palella, Frank J.; Hope, Thomas J.

    2015-01-01

    Abstract HIV is a pandemic disease, and many cellular and systemic factors are known to alter its infectivity and replication. Earlier studies had suggested that anemia is common in HIV-infected patients; however, higher iron was also observed in AIDS patients prior to the introduction of antiretroviral therapy (ART). Therefore, the relationship between iron and viral infection is not well delineated. To address this issue, we altered the levels of cellular iron in primary CD4+ T cells and showed that higher iron is associated with increased HIV infection and replication. In addition, HIV infection alone leads to increased cellular iron, and several ART drugs increase cellular iron independent of HIV infection. Finally, HIV infection is associated with increased serum iron in HIV-positive patients regardless of treatment with ART. These results establish a relationship between iron and HIV infection and suggest that iron homeostasis may be a viable therapeutic target for HIV. PMID:25291189

  18. Short communication: high cellular iron levels are associated with increased HIV infection and replication.

    PubMed

    Chang, Hsiang-Chun; Bayeva, Marina; Taiwo, Babafemi; Palella, Frank J; Hope, Thomas J; Ardehali, Hossein

    2015-03-01

    HIV is a pandemic disease, and many cellular and systemic factors are known to alter its infectivity and replication. Earlier studies had suggested that anemia is common in HIV-infected patients; however, higher iron was also observed in AIDS patients prior to the introduction of antiretroviral therapy (ART). Therefore, the relationship between iron and viral infection is not well delineated. To address this issue, we altered the levels of cellular iron in primary CD4(+) T cells and showed that higher iron is associated with increased HIV infection and replication. In addition, HIV infection alone leads to increased cellular iron, and several ART drugs increase cellular iron independent of HIV infection. Finally, HIV infection is associated with increased serum iron in HIV-positive patients regardless of treatment with ART. These results establish a relationship between iron and HIV infection and suggest that iron homeostasis may be a viable therapeutic target for HIV.

  19. GFP as potential cellular viscosimeter

    NASA Astrophysics Data System (ADS)

    Visser, Antonie J. W. G.; Westphal, Adrie H.; Skakun, Victor V.; Borst, Jan Willem

    2016-09-01

    The molecular dimensions of proteins such as green fluorescent protein (GFP) are large as compared to the ones of solvents like water or glycerol. The microscopic viscosity, which determines the resistance to diffusion of, e.g. GFP, is then the same as that determined from the resistance of the solvent to flow, which is known as macroscopic viscosity. GFP in water/glycerol mixtures senses this macroscopic viscosity, because the translational and rotational diffusion coefficients are proportional to the reciprocal value of the viscosity as predicted by the Stokes-Einstein equations. To test this hypothesis, we have performed time-resolved fluorescence anisotropy (reporting on rotational diffusion) and fluorescence correlation spectroscopy (reporting on translational diffusion) experiments of GFP in water/glycerol mixtures. When the solvent also contains macromolecules of similar or larger dimensions as GFP, the microscopic and macroscopic viscosities can be markedly different and the Stokes-Einstein relations must be adapted. It was established from previous dynamic fluorescence spectroscopy observations of diffusing proteins with dextran polysaccharides as co-solvents (Lavalette et al 2006 Eur. Biophys. J. 35 517-22), that rotation and translation sense a different microscopic viscosity, in which the one arising from rotation is always less than that from translation. A microscopic viscosity parameter is defined that depends on scaling factors between GFP and its immediate environment. The direct consequence is discussed for two reported diffusion coefficients of GFP in living cells.

  20. 76 FR 82179 - Drivers of CMVs: Restricting the Use of Cellular Phones

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Federal Motor Carrier Safety Administration 49 CFR Part 390 Drivers of CMVs: Restricting the Use of Cellular Phones AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Final...

  1. Complex I Disorders: Causes, Mechanisms, and Development of Treatment Strategies at the Cellular Level

    ERIC Educational Resources Information Center

    Valsecchi, Federica; Koopman, Werner J. H.; Manjeri, Ganesh R.; Rodenburg, Richard J.; Smeitink, Jan A. M.; Willems, Peter H. G. M.

    2010-01-01

    Mitochondrial oxidative phosphorylation (OXPHOS) represents the final step in the conversion of nutrients into cellular energy. Genetic defects in the OXPHOS system have an incidence between 1:5,000 and 1:10,000 live births. Inherited isolated deficiency of the first complex (CI) of this system, a multisubunit assembly of 45 different proteins,…

  2. Game level layout generation using evolved cellular automata

    NASA Astrophysics Data System (ADS)

    Pech, Andrew; Masek, Martin; Lam, Chiou-Peng; Hingston, Philip

    2016-01-01

    Design of level layouts typically involves the production of a set of levels which are different, yet display a consistent style based on the purpose of a particular level. In this paper, a new approach to the generation of unique level layouts, based on a target set of attributes, is presented. These attributes, which are learned automatically from an example layout, are used for the off-line evolution of a set of cellular automata rules. These rules can then be used for the real-time generation of level layouts that meet the target parameters. The approach is demonstrated on a set of maze-like level layouts. Results are presented to show the effect of various CA parameters and rule representation.

  3. Cellular Therapies Clinical Research Roadmap: Lessons learned on how to move a cellular therapy into a clinical trial

    PubMed Central

    Ouseph, Stacy; Tappitake, Darah; Armant, Myriam; Wesselschmidt, Robin; Derecho, Ivy; Draxler, Rebecca; Wood, Deborah; Centanni, John M.

    2014-01-01

    A clinical research roadmap has been developed as a resource for researchers to identify critical areas and potential pitfalls when transitioning a cellular therapy product from the research laboratory, via and Investigational New Drug (IND) application, into early phase clinical trials. The roadmap describes four key areas; basic and preclinical research, resource development, translational research and good manufacturing practice (GMP), and IND assembly and submission. Basic and preclinical research identifies a new therapeutic concept and demonstrates its potential value using a model of the relevant disease. During resource development the appropriate specialists and the required expertise to bring this product into the clinic are identified (e.g., researchers, regulatory specialists, GMP manufacturing staff, clinicians, and clinical trials staff, etc.). Additionally, the funds required to achieve this goal (or a plan to procure them) are identified. In the next phase the plan to translate the research product into a clinical grade therapeutic is developed. Finally regulatory approval to start the trial must be obtained. In the United States this is done by filing an IND application with the Food and Drug Administration. The NHLBI-funded Production Assistance for Cellular Therapies (PACT) program has facilitated the transition of a variety of cellular therapy products from the laboratory into Phase1/2 trials. The five PACT facilities have assisted investigators by performing translational studies and GMP manufacturing to ensure that cellular products met release specifications and were manufactured safely, reproducibly, and at the appropriate scale. The roadmap resulting from this experience is the focus of this article. PMID:25484311

  4. The Roles of Cellular Nanomechanics in Cancer

    PubMed Central

    Yallapu, Murali M.; Katti, Kalpana S.; Katti, Dinesh R.; Mishra, Sanjay R.; Khan, Sheema; Jaggi, Meena; Chauhan, Subhash C.

    2014-01-01

    The biomechanical properties of cells and tissues may be instrumental in increasing our understanding of cellular behavior and cellular manifestations of diseases such as cancer. Nanomechanical properties can offer clinical translation of therapies beyond what are currently employed. Nanomechanical properties, often measured by nanoindentation methods using atomic force microscopy, may identify morphological variations, cellular binding forces, and surface adhesion behaviors that efficiently differentiate normal cells and cancer cells. The aim of this review is to examine current research involving the general use of atomic force microscopy/nanoindentation in measuring cellular nanomechanics; various factors and instrumental conditions that influence the nanomechanical properties of cells; and implementation of nanoindentation methods to distinguish cancer cells from normal cells or tissues. Applying these fundamental nanomechanical properties to current discoveries in clinical treatment may result in greater efficiency in diagnosis, treatment, and prevention of cancer, which ultimately can change the lives of patients. PMID:25137233

  5. Expression of Cellular Oncogenes in Human Malignancies

    NASA Astrophysics Data System (ADS)

    Slamon, Dennis J.; Dekernion, Jean B.; Verma, Inder M.; Cline, Martin J.

    1984-04-01

    Cellular oncogenes have been implicated in the induction of malignant transformation in some model systems in vitro and may be related to malignancies in vivo in some vertebrate species. This article describes a study of the expression of 15 cellular oncogenes in fresh human tumors from 54 patients, representing 20 different tumor types. More than one cellular oncogene was transcriptionally active in all of the tumors examined. In 14 patients it was possible to study normal and malignant tissue from the same organ. In many of these patients, the transcriptional activity of certain oncogenes was greater in the malignant than the normal tissue. The cellular fes (feline sarcoma) oncogene, not previously known to be transcribed in mammalian tissue, was found to be active in lung and hematopoietic malignancies.

  6. Measurement Techniques for Cellular Biomechanics In Vitro

    PubMed Central

    Addae-Mensah, Kweku A; Wikswo, John P

    2014-01-01

    Living cells and tissues experience mechanical forces in their physiological environments that are known to affect many cellular processes. Also of importance are the mechanical properties of cells, as well as the microforces generated by cellular processes themselves in their microenvironments. The difficulty associated with studying these phenomena in vivo has led to alternatives such as using in vitro models. The need for experimental techniques for investigating cellular biomechanics and mechanobiology in vitro has fueled an evolution in the technology used in these studies. Particularly noteworthy are some of the new biomicroelectromechanical systems (BioMEMs) devices and techniques that have been introduced to the field. We describe some of the cellular micromechanical techniques and methods that have been developed for in vitro studies, and provide summaries of the ranges of measured values of various biomechanical quantities. We also briefly address some of our experiences in using these methods and include modifications we have introduced in order to improve them. PMID:18445766

  7. Cellular interactions with tissue-engineered microenvironments and nanoparticles

    NASA Astrophysics Data System (ADS)

    Pan, Zhi

    Tissue-engineered hydrogels composed of intermolecularlly crosslinked hyaluronan (HA-DTPH) and fibronectin functional domains (FNfds) were applied as a physiological relevant ECM mimic with controlled mechanical and biochemical properties. Cellular interactions with this tissue-engineered environment, especially physical interactions (cellular traction forces), were quantitatively measured by using the digital image speckle correlation (DISC) technique and finite element method (FEM). By correlating with other cell functions such as cell morphology and migration, a comprehensive structure-function relationship between cells and their environments was identified. Furthermore, spatiotemporal redistribution of cellular traction stresses was time-lapse measured during cell migration to better understand the dynamics of cell mobility. The results suggest that the reinforcement of the traction stresses around the nucleus, as well as the relaxation of nuclear deformation, are critical steps during cell migration, serving as a speed regulator, which must be considered in any dynamic molecular reconstruction model of tissue cell migration. Besides single cell migration, en masse cell migration was studied by using agarose droplet migration assay. Cell density was demonstrated to be another important parameter to influence cell behaviors besides substrate properties. Findings from these studies will provide fundamental design criteria to develop novel and effective tissue-engineered constructs. Cellular interactions with rutile and anatase TiO2 nanoparticles were also studied. These particles can penetrate easily through the cell membrane and impair cell function, with the latter being more damaging. The exposure to nanoparticles was found to decrease cell area, cell proliferation, motility, and contractility. To prevent this, a dense grafted polymer brush coating was applied onto the nanoparticle surface. These modified nanoparticles failed to adhere to and penetrate

  8. Vet Centers. Final rule.

    PubMed

    2016-03-02

    The Department of Veterans Affairs (VA) adopts as final an interim final rule that amends its medical regulation that governs Vet Center services. The National Defense Authorization Act for Fiscal Year 2013 (the 2013 Act) requires Vet Centers to provide readjustment counseling services to broader groups of veterans, members of the Armed Forces, including a member of a reserve component of the Armed Forces, and family members of such veterans and members. This final rule adopts as final the regulatory criteria to conform to the 2013 Act, to include new and revised definitions.

  9. Enhancing Therapeutic Cellular Prostate Cancer Vaccines

    DTIC Science & Technology

    2013-06-01

    10-1-0225 TITLE: “Enhancing Therapeutic Cellular Prostate Cancer Vaccines ” PRINCIPAL INVESTIGATOR: Christian R. Gomez, Ph.D...SUBTITLE “Enhancing Therapeutic Cellular Prostate Cancer Vaccines ” 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-10-1-0225 5c. PROGRAM ELEMENT...cell CaP vaccines by taking into consideration tumor-associated hypoxia as a relevant determinant of tumor antigenicity. Major Findings: Gene

  10. Cellular Effects of Perfluorinated Fatty Acids.

    DTIC Science & Technology

    1985-01-01

    TCDD appeared to interfere with fatty acid metabolism leading to an increase in unsaturation. Furthermore, Andersen et al. (2) proposed that such an...increase in cellular unsaturated fatty acids may lead-to excessive membrane fluidity (as indicated by induced changes in red blood cell fragility) and...TASK WORK UNITELEMENT NO. NO. NO. NO. 11. TITLE (include Security Claificati on) ~/~. Cellular Effects of Perfluorinated Fatty Ac ds 12. PERSONAL

  11. Recent Advances in Cellular Glycomic Analyses

    PubMed Central

    Furukawa, Jun-ichi; Fujitani, Naoki; Shinohara, Yasuro

    2013-01-01

    A large variety of glycans is intricately located on the cell surface, and the overall profile (the glycome, given the entire repertoire of glycoconjugate-associated sugars in cells and tissues) is believed to be crucial for the diverse roles of glycans, which are mediated by specific interactions that control cell-cell adhesion, immune response, microbial pathogenesis and other cellular events. The glycomic profile also reflects cellular alterations, such as development, differentiation and cancerous change. A glycoconjugate-based approach would therefore be expected to streamline discovery of novel cellular biomarkers. Development of such an approach has proven challenging, due to the technical difficulties associated with the analysis of various types of cellular glycomes; however, recent progress in the development of analytical methodologies and strategies has begun to clarify the cellular glycomics of various classes of glycoconjugates. This review focuses on recent advances in the technical aspects of cellular glycomic analyses of major classes of glycoconjugates, including N- and O-linked glycans, derived from glycoproteins, proteoglycans and glycosphingolipids. Articles that unveil the glycomics of various biologically important cells, including embryonic and somatic stem cells, induced pluripotent stem (iPS) cells and cancer cells, are discussed. PMID:24970165

  12. Transient inter-cellular polymeric linker.

    PubMed

    Ong, Siew-Min; He, Lijuan; Thuy Linh, Nguyen Thi; Tee, Yee-Han; Arooz, Talha; Tang, Guping; Tan, Choon-Hong; Yu, Hanry

    2007-09-01

    Three-dimensional (3D) tissue-engineered constructs with bio-mimicry cell-cell and cell-matrix interactions are useful in regenerative medicine. In cell-dense and matrix-poor tissues of the internal organs, cells support one another via cell-cell interactions, supplemented by small amount of the extra-cellular matrices (ECM) secreted by the cells. Here we connect HepG2 cells directly but transiently with inter-cellular polymeric linker to facilitate cell-cell interaction and aggregation. The linker consists of a non-toxic low molecular-weight polyethyleneimine (PEI) backbone conjugated with multiple hydrazide groups that can aggregate cells within 30 min by reacting with the aldehyde handles on the chemically modified cell-surface glycoproteins. The cells in the cellular aggregates proliferated; and maintained the cortical actin distribution of the 3D cell morphology while non-aggregated cells died over 7 days of suspension culture. The aggregates lost distinguishable cell-cell boundaries within 3 days; and the ECM fibers became visible around cells from day 3 onwards while the inter-cellular polymeric linker disappeared from the cell surfaces over time. The transient inter-cellular polymeric linker can be useful for forming 3D cellular and tissue constructs without bulk biomaterials or extensive network of engineered ECM for various applications.

  13. Sub-cellular proteomics of Medicago truncatula

    PubMed Central

    Lee, Jeonghoon; Lei, Zhentian; Watson, Bonnie S.; Sumner, Lloyd W.

    2013-01-01

    Medicago truncatula is a leading model species and substantial molecular, genetic, genomics, proteomics, and metabolomics resources have been developed for this species to facilitate the study of legume biology. Currently, over 60 proteomics studies of M. truncatula have been published. Many of these have focused upon the unique symbiosis formed between legumes and nitrogen fixing rhizobia bacteria, while others have focused on seed development and the specialized proteomes of distinct tissues/organs. These include the characterization of sub-cellular organelle proteomes such as nuclei and mitochondria, as well as proteins distributed in plasma or microsomal membranes from various tissues. The isolation of sub-cellular proteins typically requires a series of steps that are labor-intensive. Thus, efficient protocols for sub-cellular fractionation, purification, and enrichment are necessary for each cellular compartment. In addition, protein extraction, solubilization, separation, and digestion prior to mass spectral identification are important to enhance the detection of low abundance proteins and to increase the overall detectable proportion of the sub-cellular proteome. This review summarizes the sub-cellular proteomics studies in M. truncatula. PMID:23641248

  14. Contaminant effect on cellular metabolic differential pressure curves.

    PubMed

    Milani, Marziale; Ballerini, Monica; Ferraro, L; Zabeo, M; Barberis, M; Cannone, M; Faraone, V

    2004-01-01

    The possibility of a pressure monitoring system by differential pressure sensors to detect contaminant effects on cellular cultures metabolic activity is discussed using Saccharomyces cerevisiae, lymphocyte, and AHH1 cell cultures. Metabolic (aerobic and anaerobic) processes in cells are accompanied by CO(2) production that induces changes in pressure values when cells are cultured in sealed vessels. These values are subsequently converted in voltage units and plotted pressure dynamics versus time. This procedure leads to a standard curve, typical of the cellular line, which characterizes cellular metabolism when all parameters are controlled, such as temperature and nutrients. Different phases appear in the S. cerevisiae differential pressure curve: an initial growth up to a maximum, followed by a decrement that leads to a typical "depression" (pressure values inside the test-tubes are lower than the initial one) after about 35 h from the beginning. The S. cerevisiae differential pressure curve is successfully used to test the effects of chemical (Amuchina, trieline) and physical (UV radiation, blue light, magnetic fields) contaminants. The same technique is applied to lymphocytes and AHH1 cultures to investigate the effects generated by a 72-h exposure to a 50-Hz, 60-microT electromagnetic field. Lymphocyte samples, cultured in a PHA medium, grow less than control ones, but exhibit a greater metabolic activity: changes in the exposure system configuration influence neither sample growth differences nor metabolic response variations between control and irradiated samples, while all the other irradiation parameters remain constant. Control and irradiated lymphocyte samples, without PHA in culture medium, show the same behavior both during irradiation and metabolic test. AHH1 control and irradiated samples show no difference both in growth percentage during irradiation and in metabolic activity. Different cell cultures respond to the same stimulus in different

  15. Dirac Cellular Automaton from Split-step Quantum Walk

    PubMed Central

    Mallick, Arindam; Chandrashekar, C. M.

    2016-01-01

    Simulations of one quantum system by an other has an implication in realization of quantum machine that can imitate any quantum system and solve problems that are not accessible to classical computers. One of the approach to engineer quantum simulations is to discretize the space-time degree of freedom in quantum dynamics and define the quantum cellular automata (QCA), a local unitary update rule on a lattice. Different models of QCA are constructed using set of conditions which are not unique and are not always in implementable configuration on any other system. Dirac Cellular Automata (DCA) is one such model constructed for Dirac Hamiltonian (DH) in free quantum field theory. Here, starting from a split-step discrete-time quantum walk (QW) which is uniquely defined for experimental implementation, we recover the DCA along with all the fine oscillations in position space and bridge the missing connection between DH-DCA-QW. We will present the contribution of the parameters resulting in the fine oscillations on the Zitterbewegung frequency and entanglement. The tuneability of the evolution parameters demonstrated in experimental implementation of QW will establish it as an efficient tool to design quantum simulator and approach quantum field theory from principles of quantum information theory. PMID:27184159

  16. Dirac Cellular Automaton from Split-step Quantum Walk.

    PubMed

    Mallick, Arindam; Chandrashekar, C M

    2016-05-17

    Simulations of one quantum system by an other has an implication in realization of quantum machine that can imitate any quantum system and solve problems that are not accessible to classical computers. One of the approach to engineer quantum simulations is to discretize the space-time degree of freedom in quantum dynamics and define the quantum cellular automata (QCA), a local unitary update rule on a lattice. Different models of QCA are constructed using set of conditions which are not unique and are not always in implementable configuration on any other system. Dirac Cellular Automata (DCA) is one such model constructed for Dirac Hamiltonian (DH) in free quantum field theory. Here, starting from a split-step discrete-time quantum walk (QW) which is uniquely defined for experimental implementation, we recover the DCA along with all the fine oscillations in position space and bridge the missing connection between DH-DCA-QW. We will present the contribution of the parameters resulting in the fine oscillations on the Zitterbewegung frequency and entanglement. The tuneability of the evolution parameters demonstrated in experimental implementation of QW will establish it as an efficient tool to design quantum simulator and approach quantum field theory from principles of quantum information theory.

  17. Cellular immune responses to methylcholanthrene-induced fibrosarcoma in BALB/c mice

    PubMed Central

    1975-01-01

    Several in vitro parameters of cellular immunity were examined in BALB/c mice with an experimentally induced fibrosarcoma tumor. The results of capillary migration of spleen cells in high tumor cell dose inoculated mice show appearance of cellular immune response in the early stages of the tumor growth. As the tumor progresses, the cellular response declines and rapidly disappears, culminating in stimulation values near the time of the death of these mice. The blastogenic studies also show early cellular recognition of tumor antigen by mouse spleen cells and whole blood (Z24 h). After the 2nd day following tumor injection, no blast transformation is noted. However, the results obtained with a lower inoculating tumor cell dose demonstrate an initial cellular recognition on the 7th day. This response gradually disappears by the 19th day and remains negative up to the time of the death of these mice. This cellular immunity was confirmed by the cytotoxic experiments showing that the primary cells responsible for this cellular reactivity were the immune cells. An interesting finding was the presence of a factor(s) capable of blocking the cytotoxic effect. The nature and mechanism of this blocking factor(s) is now under investigation. PMID:1185107

  18. Cassini's Grand Finale: The Final Orbits

    NASA Astrophysics Data System (ADS)

    Spilker, Linda; Edgington, Scott

    2016-04-01

    The Cassini-Huygens mission, a joint collaboration between NASA, ESA and the Italian Space Agency, is approaching its last year of operations after nearly 12 years in orbit around Saturn. Cassini will send back its final bits of unique data on September 15th, 2017 as it plunges into Saturn's atmosphere, vaporizing and satisfying planetary protection requirements. Before that time Cassini will continue its legacy of exploration and discovery with 12 close flybys of Titan in 2016 and 2017 that will return new science data as well as sculpt the inclinations and periods of the final orbits. Even though all of our close icy satellite flybys, including those of Enceladus, are now completed, numerous Voyager-class flybys (<100,000 km) of Mimas and Enceladus remain as well as some of our best flybys of the tiny ring moons. Cassini will also continue to study seasonal and temporal changes in the system as northern summer solstice approaches. In November 2016 Cassini will transition to a series of orbits with peripases just outside Saturn's F ring. These 20 orbits will include close flybys of some tiny ring moons and excellent views of the F ring and outer A ring. The 126th and final close flyby of Titan will propel Cassini across Saturn's main rings and into its final orbits. Cassini's Grand Finale, starting in April 2017, is comprised of 22 orbits at an inclination of 63 degrees. Cassini will repeatedly dive between the innermost rings and the upper atmosphere of the planet providing insights into fundamental questions unattainable during the rest of the mission. Cassini will be the first spacecraft to explore this region. These close orbits provide the highest resolution observations of both the rings and Saturn, and direct in situ sampling of the ring particles, composition, plasma, Saturn's exosphere and the innermost radiation belts. Saturn's gravitational field will be measured to unprecedented accuracy, providing information on the interior structure of the planet

  19. Cellular heredity in haploid cultures of somatic cells, March 1968-April 1981. Final report

    SciTech Connect

    Freed, J.J.

    1982-03-01

    An account is given of the development and application to cell-culture genetics of unique haploid cell lines from frog embryo developed in this laboratory. Since 1968, the main aim of this project has been to develop the haploid cell system for studies of mutagenesis in culture, particularly by ultraviolet radiation. In the course of this work we isolated chromosomally stable cell lines, derived and characterized a number of variants, and adapted cell hybridization and other methods to this material. Particular emphasis was placed on ultraviolet photobiology, including studies of cell survival, mutagenesis, and pathways of repair of uv-damaged DNA. Although at present less widely used for genetic experiments than mammalian cell lines, the frog cells offer the advantages of authentic haploidy and a favorable repertory of DNA repair pathways for study of uv mutagenesis.

  20. Final Report on the Freeze-Drying of Cellular Materials: Cryopharm Research Report

    DTIC Science & Technology

    1993-09-14

    Buffer Water (msec) III Carbohydrate (sac) Cell Shrinks 1. Freeze 2. Dry • Water (insec) Store Dry Rehydrate Cell f l ; • • • • Swells H-b leaks...With drying , water is removed from the ice phase during primary drying and then is sublimed from thp glassy phase during secondary drying. Normally

  1. Cellular systems for toxicity testing. Final report 1 Sep 82-31 Aug 83

    SciTech Connect

    Williams, G.M.; Dunkel, V.C.; Ray, V.A.

    1983-06-01

    Metabolism and End Points of In Vitro Systems, Cytotoxicity, DNA Damage, Chromosome Effects, Mutagenicity Systems, Mammalian Mutagenesis, Transformation Systems, Effects of Tumor Promoters, Mechanistic Significance and Relevance of Short-Term Tests, Application of Short-Term Tests to Chemical Safety Evaluation, and Poster Papers.

  2. Magnetic fields, radicals and cellular activity.

    PubMed

    Montoya, Ryan D

    2017-01-01

    Some effects of low-intensity magnetic fields on the concentration of radicals and their influence on cellular functions are reviewed. These fields have been implicated as a potential modulator of radical recombination rates. Experimental evidence has revealed a tight coupling between cellular function and radical pair chemistry from signaling pathways to damaging oxidative processes. The effects of externally applied magnetic fields on biological systems have been extensively studied, and the observed effects lack sufficient mechanistic understanding. Radical pair chemistry offers a reasonable explanation for some of the molecular effects of low-intensity magnetic fields, and changes in radical concentrations have been observed to modulate specific cellular functions. Applied external magnetic fields have been shown to induce observable cellular changes such as both inhibiting and accelerating cell growth. These and other mechanisms, such as cell membrane potential modulation, are of great interest in cancer research due to the variations between healthy and deleterious cells. Radical concentrations demonstrate similar variations and are indicative of a possible causal relationship. Radicals, therefore, present a possible mechanism for the modulation of cellular functions such as growth or regression by means of applied external magnetic fields.

  3. Complexity, dynamic cellular network, and tumorigenesis.

    PubMed

    Waliszewski, P

    1997-01-01

    A holistic approach to tumorigenesis is proposed. The main element of the model is the existence of dynamic cellular network. This network comprises a molecular and an energetistic structure of a cell connected through the multidirectional flow of information. The interactions within dynamic cellular network are complex, stochastic, nonlinear, and also involve quantum effects. From this non-reductionist perspective, neither tumorigenesis can be limited to the genetic aspect, nor the initial event must be of molecular nature, nor mutations and epigenetic factors are mutually exclusive, nor a link between cause and effect can be established. Due to complexity, an unstable stationary state of dynamic cellular network rather than a group of unrelated genes determines the phenotype of normal and transformed cells. This implies relativity of tumor suppressor genes and oncogenes. A bifurcation point is defined as an unstable state of dynamic cellular network leading to the other phenotype-stationary state. In particular, the bifurcation point may be determined by a change of expression of a single gene. Then, the gene is called bifurcation point gene. The unstable stationary state facilitates the chaotic dynamics. This may result in a fractal dimension of both normal and tumor tissues. The co-existence of chaotic dynamics and complexity is the essence of cellular processes and shapes differentiation, morphogenesis, and tumorigenesis. In consequence, tumorigenesis is a complex, unpredictable process driven by the interplay between self-organisation and selection.

  4. GALAPAGOS: from pixels to parameters

    NASA Astrophysics Data System (ADS)

    Barden, Marco; Häußler, Boris; Peng, Chien Y.; McIntosh, Daniel H.; Guo, Yicheng

    2012-05-01

    To automate source detection, two-dimensional light profile Sérsic modelling and catalogue compilation in large survey applications, we introduce a new code Galaxy Analysis over Large Areas: Parameter Assessment by GALFITting Objects from SEXTRACTOR (GALAPAGOS). Based on a single set-up, GALAPAGOS can process a complete set of survey images. It detects sources in the data, estimates a local sky background, cuts postage stamp images for all sources, prepares object masks, performs Sérsic fitting including neighbours and compiles all objects in a final output catalogue. For the initial source detection, GALAPAGOS applies SEXTRACTOR, while GALFIT is incorporated for modelling Sérsic profiles. It measures the background sky involved in the Sérsic fitting by means of a flux growth curve. GALAPAGOS determines postage stamp sizes based on SEXTRACTOR shape parameters. In order to obtain precise model parameters, GALAPAGOS incorporates a complex sorting mechanism and makes use of modern CPU's multiplexing capabilities. It combines SEXTRACTOR and GALFIT data in a single output table. When incorporating information from overlapping tiles, GALAPAGOS automatically removes multiple entries from identical sources. GALAPAGOS is programmed in the Interactive Data Language (IDL). We test the stability and the ability to properly recover structural parameters extensively with artificial image simulations. Moreover, we apply GALAPAGOS successfully to the STAGES data set. For one-orbit Hubble Space Telescope data, a single 2.2-GHz CPU processes about 1000 primary sources per 24 h. Note that GALAPAGOS results depend critically on the user-defined parameter set-up. This paper provides useful guidelines to help the user make sensible choices.

  5. Studies on the control of plant cell enlargement by cellular parameters

    SciTech Connect

    Cleland, R.E.

    1991-12-06

    The overall goal of this grant was to conduct research that would illuminate the mechanisms by which the plant hormone auxin induces plant cells to enlarge. A large body of knowledge already existed concerning this process. To begin with, it had been demonstrated, primarily by this laboratory during previous grant periods, that the effect of auxin is to cause a loosening of the cell wall, which is followed by turgor-driven wall expansion and water uptake. The wall contains a series of load-bearing wall bonds which must be cleaved in order to loosen the wall. The identification of these load-bearing bonds is one goal of this research. We proposed that an initial action of auxin is to cause cells to excrete protons, and that the resulting acidification of the apoplast activated enzymes responsible for wall loosening. Evidence has been obtained that indicates that the proton excretion is due to an enhanced activity of the plasma membrane H{sup +} {minus}ATPase. A critical question is how auxin activates this enzyme. The third project concerned the role of wall calcium as part of load-bearing wall bonds. It has long been thought that apoplastic calcium crosslinks carboxyl groups in the wall pectic substances and stiffens the walls. We examined the role of calcium-bridges as load-bearing bonds in soybean hypocotyl cell walls in two ways. The first was to measure the viscoelastic extensibility of walls after addition of exogenous calcium or removal of endogenous calcium. The second approach was to determine if removal of wall calcium from walls while under tension resulted in wall extension, as predicted if the calcium-bridges were load-bearing bonds.

  6. Parameter Identifiability of Fundamental Pharmacodynamic Models

    PubMed Central

    Janzén, David L. I.; Bergenholm, Linnéa; Jirstrand, Mats; Parkinson, Joanna; Yates, James; Evans, Neil D.; Chappell, Michael J.

    2016-01-01

    Issues of parameter identifiability of routinely used pharmacodynamics models are considered in this paper. The structural identifiability of 16 commonly applied pharmacodynamic model structures was analyzed analytically, using the input-output approach. Both fixed-effects versions (non-population, no between-subject variability) and mixed-effects versions (population, including between-subject variability) of each model structure were analyzed. All models were found to be structurally globally identifiable under conditions of fixing either one of two particular parameters. Furthermore, an example was constructed to illustrate the importance of sufficient data quality and show that structural identifiability is a prerequisite, but not a guarantee, for successful parameter estimation and practical parameter identifiability. This analysis was performed by generating artificial data of varying quality to a structurally identifiable model with known true parameter values, followed by re-estimation of the parameter values. In addition, to show the benefit of including structural identifiability as part of model development, a case study was performed applying an unidentifiable model to real experimental data. This case study shows how performing such an analysis prior to parameter estimation can improve the parameter estimation process and model performance. Finally, an unidentifiable model was fitted to simulated data using multiple initial parameter values, resulting in highly different estimated uncertainties. This example shows that although the standard errors of the parameter estimates often indicate a structural identifiability issue, reasonably “good” standard errors may sometimes mask unidentifiability issues. PMID:27994553

  7. Kinetic theory approach to modeling of cellular repair mechanisms under genome stress.

    PubMed

    Qi, Jinpeng; Ding, Yongsheng; Zhu, Ying; Wu, Yizhi

    2011-01-01

    Under acute perturbations from outer environment, a normal cell can trigger cellular self-defense mechanism in response to genome stress. To investigate the kinetics of cellular self-repair process at single cell level further, a model of DNA damage generating and repair is proposed under acute Ion Radiation (IR) by using mathematical framework of kinetic theory of active particles (KTAP). Firstly, we focus on illustrating the profile of Cellular Repair System (CRS) instituted by two sub-populations, each of which is made up of the active particles with different discrete states. Then, we implement the mathematical framework of cellular self-repair mechanism, and illustrate the dynamic processes of Double Strand Breaks (DSBs) and Repair Protein (RP) generating, DSB-protein complexes (DSBCs) synthesizing, and toxins accumulating. Finally, we roughly analyze the capability of cellular self-repair mechanism, cellular activity of transferring DNA damage, and genome stability, especially the different fates of a certain cell before and after the time thresholds of IR perturbations that a cell can tolerate maximally under different IR perturbation circumstances.

  8. Sirtuin 2 regulates cellular iron homeostasis via deacetylation of transcription factor NRF2.

    PubMed

    Yang, Xiaoyan; Park, Seong-Hoon; Chang, Hsiang-Chun; Shapiro, Jason S; Vassilopoulos, Athanassios; Sawicki, Konrad T; Chen, Chunlei; Shang, Meng; Burridge, Paul W; Epting, Conrad L; Wilsbacher, Lisa D; Jenkitkasemwong, Supak; Knutson, Mitchell; Gius, David; Ardehali, Hossein

    2017-03-13

    SIRT2 is a cytoplasmic sirtuin that plays a role in various cellular processes, including tumorigenesis, metabolism, and inflammation. Since these processes require iron, we hypothesized that SIRT2 directly regulates cellular iron homeostasis. Here, we have demonstrated that SIRT2 depletion results in a decrease in cellular iron levels both in vitro and in vivo. Mechanistically, we determined that SIRT2 maintains cellular iron levels by binding to and deacetylating nuclear factor erythroid-derived 2-related factor 2 (NRF2) on lysines 506 and 508, leading to a reduction in total and nuclear NRF2 levels. The reduction in nuclear NRF2 leads to reduced ferroportin 1 (FPN1) expression, which in turn results in decreased cellular iron export. Finally, we observed that Sirt2 deletion reduced cell viability in response to iron deficiency. Moreover, livers from Sirt2-/- mice had decreased iron levels, while this effect was reversed in Sirt2-/- Nrf2-/- double-KO mice. Taken together, our results uncover a link between sirtuin proteins and direct control over cellular iron homeostasis via regulation of NRF2 deacetylation and stability.

  9. Cellular therapies for type 1 diabetes.

    PubMed

    Lee, D D; Grossman, E; Chong, A S

    2008-02-01

    Type 1 diabetes mellitus (T1DM) is a disease that results from the selective autoimmune destruction of insulin-producing beta-cells. This disease process lends itself to cellular therapy because of the single cell nature of insulin production. Murine models have provided opportunities for the study of cellular therapies for the treatment of diabetes, including the investigation of islet transplantation, and also the possibility of stem cell therapies and islet regeneration. Studies in islet transplantation have included both allo- and xeno-transplantation and have allowed for the study of new approaches for the reversal of autoimmunity and achieving immune tolerance. Stem cells from hematopoietic sources such as bone marrow and fetal cord blood, as well as from the pancreas, intestine, liver, and spleen promise either new sources of islets or may function as stimulators of islet regeneration. This review will summarize the various cellular interventions investigated as potential treatments of T1DM.

  10. Role of galactose in cellular senescence.

    PubMed

    Elzi, David J; Song, Meihua; Shiio, Yuzuru

    2016-01-01

    Cellular senescence has been proposed to play critical roles in tumor suppression and organismal aging, but the molecular mechanism of senescence remains incompletely understood. Here we report that a putative lysosomal carbohydrate efflux transporter, Spinster, induces cellular senescence in human primary fibroblasts. Administration of d-galactose synergistically enhanced Spinster-induced senescence and this synergism required the transporter activity of Spinster. Intracellular d-galactose is metabolized to galactose-1-phosphate by galactokinase. Galactokinase-deficient fibroblasts, which accumulate intracellular d-galactose, displayed increased baseline senescence. Senescence of galactokinase-deficient fibroblasts was further enhanced by d-galactose administration and was diminished by restoration of wild-type galactokinase expression. Silencing galactokinase in normal fibroblasts also induced senescence. These results suggest a role for intracellular galactose in the induction of cellular senescence.

  11. Mesoporous silica nanoparticles inhibit cellular respiration.

    PubMed

    Tao, Zhimin; Morrow, Matthew P; Asefa, Tewodros; Sharma, Krishna K; Duncan, Cole; Anan, Abhishek; Penefsky, Harvey S; Goodisman, Jerry; Souid, Abdul-Kader

    2008-05-01

    We studied the effect of two types of mesoporous silica nanoparticles, MCM-41 and SBA-15, on mitochondrial O 2 consumption (respiration) in HL-60 (myeloid) cells, Jurkat (lymphoid) cells, and isolated mitochondria. SBA-15 inhibited cellular respiration at 25-500 microg/mL; the inhibition was concentration-dependent and time-dependent. The cellular ATP profile paralleled that of respiration. MCM-41 had no noticeable effect on respiration rate. In cells depleted of metabolic fuels, 50 microg/mL SBA-15 delayed the onset of glucose-supported respiration by 12 min and 200 microg/mL SBA-15 by 34 min; MCM-41 also delayed the onset of glucose-supported respiration. Neither SBA-15 nor MCM-41 affected cellular glutathione. Both nanoparticles inhibited respiration of isolated mitochondria and submitochondrial particles.

  12. Geroconversion: irreversible step to cellular senescence

    PubMed Central

    Blagosklonny, Mikhail V

    2014-01-01

    Cellular senescence happens in 2 steps: cell cycle arrest followed, or sometimes preceded, by gerogenic conversion (geroconversion). Geroconvesrion is a form of growth, a futile growth during cell cycle arrest. It converts reversible arrest to irreversible senescence. Geroconversion is driven by growth-promoting, mitogen-/nutrient-sensing pathways such as mTOR. Geroconversion leads to hyper-secretory, hypertrophic and pro-inflammatory cellular phenotypes, hyperfunctions and malfunctions. On organismal level, geroconversion leads to age-related diseases and death. Rapamycin, a gerosuppressant, extends life span in diverse species from yeast to mammals. Stress–and oncogene-induced accelerated senescence, replicative senescence in vitro and life-long cellular aging in vivo all can be described by 2-step model. PMID:25483060

  13. Crack Propagation in Bamboo's Hierarchical Cellular Structure

    PubMed Central

    Habibi, Meisam K.; Lu, Yang

    2014-01-01

    Bamboo, as a natural hierarchical cellular material, exhibits remarkable mechanical properties including excellent flexibility and fracture toughness. As far as bamboo as a functionally graded bio-composite is concerned, the interactions of different constituents (bamboo fibers; parenchyma cells; and vessels.) alongside their corresponding interfacial areas with a developed crack should be of high significance. Here, by using multi-scale mechanical characterizations coupled with advanced environmental electron microscopy (ESEM), we unambiguously show that fibers' interfacial areas along with parenchyma cells' boundaries were preferred routes for crack growth in both radial and longitudinal directions. Irrespective of the honeycomb structure of fibers along with cellular configuration of parenchyma ground, the hollow vessels within bamboo culm affected the crack propagation too, by crack deflection or crack-tip energy dissipation. It is expected that the tortuous crack propagation mode exhibited in the present study could be applicable to other cellular natural materials as well. PMID:24998298

  14. Crack propagation in bamboo's hierarchical cellular structure.

    PubMed

    Habibi, Meisam K; Lu, Yang

    2014-07-07

    Bamboo, as a natural hierarchical cellular material, exhibits remarkable mechanical properties including excellent flexibility and fracture toughness. As far as bamboo as a functionally graded bio-composite is concerned, the interactions of different constituents (bamboo fibers; parenchyma cells; and vessels.) alongside their corresponding interfacial areas with a developed crack should be of high significance. Here, by using multi-scale mechanical characterizations coupled with advanced environmental electron microscopy (ESEM), we unambiguously show that fibers' interfacial areas along with parenchyma cells' boundaries were preferred routes for crack growth in both radial and longitudinal directions. Irrespective of the honeycomb structure of fibers along with cellular configuration of parenchyma ground, the hollow vessels within bamboo culm affected the crack propagation too, by crack deflection or crack-tip energy dissipation. It is expected that the tortuous crack propagation mode exhibited in the present study could be applicable to other cellular natural materials as well.

  15. Cellular Models for the Study of Prions.

    PubMed

    Holmes, Brandon B; Diamond, Marc I

    2017-02-01

    It is now established that numerous amyloid proteins associated with neurodegenerative diseases, including tau and α-synuclein, have essential characteristics of prions, including the ability to create transmissible cellular pathology in vivo. We have developed cellular bioassays that report on the various features of prion activity using genetic engineering and quantitative fluorescence-based detection systems. We have exploited these biosensors to measure the binding and uptake of tau seeds into cells in culture and to quantify seeding activity in brain samples. These cell models have also been used to propagate tau prion strains indefinitely in culture. In this review, we illustrate the utility of cellular biosensors to gain mechanistic insight into prion transmission and to study neurodegenerative diseases in a reductionist fashion.

  16. Cellular immunity to Bacteroides fragilis capsular polysaccharide

    PubMed Central

    1982-01-01

    The polysaccharide capsule of Bacteroides fragilis has been shown to be important in the virulence of the organism. The capsular polysaccharide (CP) of B. fragilis has been extensively purified. Using a murine model of intraabdominal abscess formation, we have been able to demonstrate cellular immunity to the capsular polysaccharide of B. fragilis. Immunization of C57BL/10J mice with the CP over 5 wk prevents abscess formation when the mice are challenged with B. fragilis intraperitoneally. This immunity can be transferred to naive mice with spleen cells from immune animals. The immune cells bear Thy-1.2 and Ly- 2.2 antigens. The immune response has been shown to be antigen specific, but not H-2 restricted. The possibility that these immune cells are suppressor T cells is discussed. The experimental system presented provides a model for the examination of the cellular interactions responsible for abscess formation and the cellular response to bacterial pathogens. PMID:6174672

  17. Parameter Plane Design Method

    DTIC Science & Technology

    1989-03-01

    Th usr a toente aninteer a thca sms b esta 1 Fp-ocsing 2. Enter P1 values, lwgt, ldig - > 9 Table I give us proper values. Table 1. PARAMETER TABLE...necessary and identify by block number) In this thesis a control systems analysis package is developed using parameter plane methods. It is an interactive...designer is able to choose values of the parameters which provide a good compromise between cost and dynamic behavior. 20 Distribution Availability of

  18. HYDROGEN ATOM THERMAL PARAMETERS.

    PubMed

    JENSEN, L H; SUNDARALINGAM, M

    1964-09-11

    Isotropic hydrogen atom thermal parameters for N,N'- hexamethylenebispropionamide have been determined. They show a definite trend and vary from approximately the same as the mean thermal parameters for atoms other than hydrogen near the center of the molecule to appreciably greater for atoms near the end. The indicated trend for this compound, along with other results, provides the basis for a possible explanation of the anomolous values that have been obtained for hydrogen atom thermal parameters.

  19. Endeavour's Final Voyage

    NASA Video Gallery

    After nearly two decades of achievements in space, Endeavour makes one last reach for the stars on its 25th and final mission, STS-134. This webcast examines the mission to come and explores the st...

  20. Final focus nomenclature

    SciTech Connect

    Erickson, R.

    1986-08-08

    The formal names and common names for all devices in the final focus system of the SLC are listed. The formal names consist of a device type designator, microprocessor designator, and a four-digit unit number. (LEW)

  1. Final focus test beam

    SciTech Connect

    Not Available

    1991-03-01

    This report discusses the following: the Final Focus Test Beam Project; optical design; magnets; instrumentation; magnetic measurement and BPM calibration; mechanical alignment and stabilization; vacuum system; power supplies; control system; radiation shielding and personnel protection; infrastructure; and administration.

  2. Expedition 34 Final Training

    NASA Video Gallery

    The Expedition 34 crew members conduct final training at the Gagarin Cosmonaut Training Center before their Dec. 19 launch to the International Space Station. Flight Engineers Chris Hadfield, Roman...

  3. Identification of optimal parameter combinations for the emergence of bistability.

    PubMed

    Májer, Imre; Hajihosseini, Amirhossein; Becskei, Attila

    2015-11-24

    Bistability underlies cellular memory and maintains alternative differentiation states. Bistability can emerge only if its parameter range is either physically realizable or can be enlarged to become realizable. We derived a general rule and showed that the bistable range of a reaction parameter is maximized by a pair of other parameters in any gene regulatory network provided they satisfy a general condition. The resulting analytical expressions revealed whether or not such reaction pairs are present in prototypical positive feedback loops. They are absent from the feedback loop enclosed by protein dimers but present in both the toggle-switch and the feedback circuit inhibited by sequestration. Sequestration can generate bistability even at narrow feedback expression range at which cooperative binding fails to do so, provided inhibition is set to an optimal value. These results help to design bistable circuits and cellular reprogramming and reveal whether bistability is possible in gene networks in the range of realistic parameter values.

  4. Modelling of the cellular automata space deformation within the RCAFE framework

    NASA Astrophysics Data System (ADS)

    Sitko, Mateusz; Madej, Łukasz

    2016-10-01

    Development of the innovative approach to micro scale cellular automata (CA) space deformation during dynamic recrystallization process (DRX) is the main goal of the present paper. Major assumptions of the developed CA DRX model as well as novel space deformation algorithm, which is based on the random cellular automata concept and FE method, are described. Algorithms and methods to transfer input/output data between FE and CA are presented in detail. Visualization tool to analyze progress of deformation in the irregular CA space is also highlighted. Finally, initial results in the form of deformed and recrystallized microstructures are presented and discussed.

  5. Cellular reprogramming through mitogen-activated protein kinases

    PubMed Central

    Lee, Justin; Eschen-Lippold, Lennart; Lassowskat, Ines; Böttcher, Christoph; Scheel, Dierk

    2015-01-01

    Mitogen-activated protein kinase (MAPK) cascades are conserved eukaryote signaling modules where MAPKs, as the final kinases in the cascade, phosphorylate protein substrates to regulate cellular processes. While some progress in the identification of MAPK substrates has been made in plants, the knowledge on the spectrum of substrates and their mechanistic action is still fragmentary. In this focused review, we discuss the biological implications of the data in our original paper (Sustained mitogen-activated protein kinase activation reprograms defense metabolism and phosphoprotein profile in Arabidopsis thaliana; Frontiers in Plant Science 5: 554) in the context of related research. In our work, we mimicked in vivo activation of two stress-activated MAPKs, MPK3 and MPK6, through transgenic manipulation of Arabidopsis thaliana and used phosphoproteomics analysis to identify potential novel MAPK substrates. Here, we plotted the identified putative MAPK substrates (and downstream phosphoproteins) as a global protein clustering network. Based on a highly stringent selection confidence level, the core networks highlighted a MAPK-induced cellular reprogramming at multiple levels of gene and protein expression—including transcriptional, post-transcriptional, translational, post-translational (such as protein modification, folding, and degradation) steps, and also protein re-compartmentalization. Additionally, the increase in putative substrates/phosphoproteins of energy metabolism and various secondary metabolite biosynthesis pathways coincides with the observed accumulation of defense antimicrobial substances as detected by metabolome analysis. Furthermore, detection of protein networks in phospholipid or redox elements suggests activation of downstream signaling events. Taken in context with other studies, MAPKs are key regulators that reprogram cellular events to orchestrate defense signaling in eukaryotes. PMID:26579181

  6. New NLC Final Focus

    SciTech Connect

    Raimondi, P.

    2004-10-11

    A novel design of the Final Focus has recently been proposed [1] and has been adopted now for the Next Linear Collider [2]. This new design has fewer optical elements and is much shorter, nonetheless achieving better chromatic properties. In this paper, the new final focus system is briefly discussed stressing one particular characteristic of the new design--its multi TeV energy reach.

  7. Data breaches. Final rule.

    PubMed

    2008-04-11

    This document adopts, without change, the interim final rule that was published in the Federal Register on June 22, 2007, addressing data breaches of sensitive personal information that is processed or maintained by the Department of Veterans Affairs (VA). This final rule implements certain provisions of the Veterans Benefits, Health Care, and Information Technology Act of 2006. The regulations prescribe the mechanisms for taking action in response to a data breach of sensitive personal information.

  8. Cellular Stress Response to Engineered Nanoparticles: Effect of Size, Surface Coating, and Cellular Uptake

    EPA Science Inventory

    CELLULAR STRESS RESPONSE TO ENGINEERED NANOPARTICLES: EFFECT OF SIZE, SURFACE COATING, AND CELLULAR UPTAKE RY Prasad 1, JK McGee2, MG Killius1 D Ackerman2, CF Blackman2 DM DeMarini2 , SO Simmons2 1 Student Services Contractor, US EPA, RTP, NC 2 US EPA, RTP, NC The num...

  9. GRCop-84 Rolling Parameter Study

    NASA Technical Reports Server (NTRS)

    Loewenthal, William S.; Ellis, David L.

    2008-01-01

    This report is a section of the final report on the GRCop-84 task of the Constellation Program and incorporates the results obtained between October 2000 and September 2005, when the program ended. NASA Glenn Research Center (GRC) has developed a new copper alloy, GRCop-84 (Cu-8 at.% Cr-4 at.% Nb), for rocket engine main combustion chamber components that will improve rocket engine life and performance. This work examines the sensitivity of GRCop-84 mechanical properties to rolling parameters as a means to better define rolling parameters for commercial warm rolling. Experiment variables studied were total reduction, rolling temperature, rolling speed, and post rolling annealing heat treatment. The responses were tensile properties measured at 23 and 500 C, hardness, and creep at three stress-temperature combinations. Understanding these relationships will better define boundaries for a robust commercial warm rolling process. The four processing parameters were varied within limits consistent with typical commercial production processes. Testing revealed that the rolling-related variables selected have a minimal influence on tensile, hardness, and creep properties over the range of values tested. Annealing had the expected result of lowering room temperature hardness and strength while increasing room temperature elongations with 600 C (1112 F) having the most effect. These results indicate that the process conditions to warm roll plate and sheet for these variables can range over wide levels without negatively impacting mechanical properties. Incorporating broader process ranges in future rolling campaigns should lower commercial rolling costs through increased productivity.

  10. Protective cellular antigen of Clostridium chauvoei.

    PubMed

    Stevenson, J R; Stonger, K A

    1980-04-01

    Cellular antigens of Clostridium chauvoei, strain IRP-128, were demonstrated to be important in induction of immunity against this bacterium in guinea pigs. At least one major component of the cellular antigen complex was heat-labile. Acid extraction of the bacterial cells, followed by selective purification for flagella, led to the preparation of an acid extract antigen that possessed a high degree of immunogenicity. The acid extract antigen contained flagellar components and was resolved into two major and approximately five minor protein components by polyacrylamide-gel electrophoresis.

  11. Toxicology and cellular effect of manufactured nanomaterials

    DOEpatents

    Chen, Fanqing

    2014-07-22

    The increasing use of nanotechnology in consumer products and medical applications underlies the importance of understanding its potential toxic effects to people and the environment. Herein are described methods and assays to predict and evaluate the cellular effects of nanomaterial exposure. Exposing cells to nanomaterials at cytotoxic doses induces cell cycle arrest and increases apoptosis/necrosis, activates genes involved in cellular transport, metabolism, cell cycle regulation, and stress response. Certain nanomaterials induce genes indicative of a strong immune and inflammatory response within skin fibroblasts. Furthermore, the described multiwall carbon nanoonions (MWCNOs) can be used as a therapeutic in the treatment of cancer due to its cytotoxicity.

  12. Inferring cellular networks using probabilistic graphical models.

    PubMed

    Friedman, Nir

    2004-02-06

    High-throughput genome-wide molecular assays, which probe cellular networks from different perspectives, have become central to molecular biology. Probabilistic graphical models are useful for extracting meaningful biological insights from the resulting data sets. These models provide a concise representation of complex cellular networks by composing simpler submodels. Procedures based on well-understood principles for inferring such models from data facilitate a model-based methodology for analysis and discovery. This methodology and its capabilities are illustrated by several recent applications to gene expression data.

  13. Cellular Mechanisms of Central Nervous Modulation.

    DTIC Science & Technology

    1983-06-30

    achieve selective disruption of the neuroglia in the central nervous system 4 of our experimental animal, the cockroach (Periplaneta americana). Such...RD-A147 878 CELLULAR MECHANISMIS OF CENTRAL NERVOUS MODULATION(U) i/i I CAMBRIDGE UNIV (ENGLAND) DEPT OF ZOOLOGY J E TRENERNE 30 JUN 83 DHJA37-8i-C...BOOBI UNCLASSFE F/G 6/16 NL bi L& 2. MICROCOPY RESOLUTION TEST CHART NATIONA BUJREAUJ OF STANDOW-S1963-A [.1 PI CELLULAR MECHANISMIS OF CENTRAL NERVOUS

  14. System and method for monitoring cellular activity

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory H. (Inventor); Fraser, Scott E. (Inventor); Lansford, Russell D. (Inventor)

    2004-01-01

    A system and method for monitoring cellular activity in a cellular specimen. According to one embodiment, a plurality of excitable markers are applied to the specimen. A multi-photon laser microscope is provided to excite a region of the specimen and cause fluorescence to be radiated from the region. The radiating fluorescence is processed by a spectral analyzer to separate the fluorescence into respective wavelength bands. The respective bands of fluorescence are then collected by an array of detectors, with each detector receiving a corresponding one of the wavelength bands.

  15. System and method for monitoring cellular activity

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory H. (Inventor); Fraser, Scott E. (Inventor); Lansford, Russell D. (Inventor)

    2002-01-01

    A system and method for monitoring cellular activity in a cellular specimen. According to one embodiment, a plurality of excitable markers are applied to the specimen. A multi-photon laser microscope is provided to excite a region of the specimen and cause fluorescence to be radiated from the region. The radiating fluorescence is processed by a spectral analyzer to separate the fluorescence into respective wavelength bands. The respective bands of fluorescence are then collected by an array of detectors, with each detector receiving a corresponding one of the wavelength bands.

  16. Cellular Automata Simulation for Wealth Distribution

    NASA Astrophysics Data System (ADS)

    Lo, Shih-Ching

    2009-08-01

    Wealth distribution of a country is a complicate system. A model, which is based on the Epstein & Axtell's "Sugars cape" model, is presented in Netlogo. The model considers the income, age, working opportunity and salary as control variables. There are still other variables should be considered while an artificial society is established. In this study, a more complicate cellular automata model for wealth distribution model is proposed. The effects of social welfare, tax, economical investment and inheritance are considered and simulated. According to the cellular automata simulation for wealth distribution, we will have a deep insight of financial policy of the government.

  17. Cellular basis of Alzheimer’s disease

    PubMed Central

    Bali, Jitin; Halima, Saoussen Ben; Felmy, Boas; Goodger, Zoe; Zurbriggen, Sebastian; Rajendran, Lawrence

    2010-01-01

    Alzheimer’s disease (AD) is the most common form of neurodegenerative disease. A characteristic feature of the disease is the presence of amyloid-β (Aβ) which either in its soluble oligomeric form or in the plaque-associated form is causally linked to neurodegeneration. Aβ peptide is liberated from the membrane-spanning -amyloid precursor protein by sequential proteolytic processing employing β- and γ-secretases. All these proteins involved in the production of Aβ peptide are membrane associated and hence, membrane trafficking and cellular compartmentalization play important roles. In this review, we summarize the key cellular events that lead to the progression of AD. PMID:21369424

  18. Cellular studies and interaction mechanisms of extremely low frequency fields

    NASA Astrophysics Data System (ADS)

    Liburdy, Robert P.

    1995-01-01

    Worldwide interest in the biological effects of ELF (extremely low frequency, <1 kHz) electromagnetic fields has grown significantly. Health professionals and government administrators and regulators, scientists and engineers, and, importantly, an increasing number of individuals in the general public are interested in this health issue. The goal of research at the cellular level is to identify cellular responses to ELF fields, to develop a dose threshold for such interactions, and with such information to formulate and test appropriate interaction mechanisms. This review is selective and will discuss the most recent cellular studies directed at these goals which relate to power line, sinusoidal ELF fields. In these studies an interaction site at the cell membrane is by consensus a likely candidate, since changes in ion transport, ligand-receptor events such as antibody binding, and G protein activation have been reported. These changes strongly indicate that signal transduction (ST) can be influenced. Also, ELF fields are reported to influence enzyme activation, gene expression, protein synthesis, and cell proliferation, which are triggered by earlier ST events at the cell membrane. The concept of ELF fields altering early cell membrane events and thereby influencing intracellular cell function via the ST cascade is perhaps the most plausible biological framework currently being investigated for understanding ELF effects on cells. For example, the consequence of an increase due to ELF fields in mitogenesis, the final endpoint of the ST cascade, is an overall increase in the probability of mutagenesis and consequently cancer, according to the Ames epigenetic model of carcinogenesis. Consistent with this epigenetic mechanism and the ST pathway to carcinogenesis is recent evidence that ELF fields can alter breast cancer cell proliferation and can act as a copromoter in vitro. The most important dosimetric question being addressed currently is whether the electric (E

  19. Neurophysiology of HCN channels: from cellular functions to multiple regulations.

    PubMed

    He, Chao; Chen, Fang; Li, Bo; Hu, Zhian

    2014-01-01

    Hyperpolarization-activated cyclic nucleotide-gated (HCN) cation channels are encoded by HCN1-4 gene family and have four subtypes. These channels are activated upon hyperpolarization of membrane potential and conduct an inward, excitatory current Ih in the nervous system. Ih acts as pacemaker current to initiate rhythmic firing, dampen dendritic excitability and regulate presynaptic neurotransmitter release. This review summarizes recent insights into the cellular functions of Ih and associated behavior such as learning and memory, sleep and arousal. HCN channels are excellent targets of various cellular signals to finely regulate neuronal responses to external stimuli. Numerous mechanisms, including transcriptional control, trafficking, as well as channel assembly and modification, underlie HCN channel regulation. In the next section, we discuss how the intracellular signals, especially recent findings concerning protein kinases and interacting proteins such as cGKII, Ca(2+)/CaMKII and TRIP8b, regulate function and expression of HCN channels, and subsequently provide an overview of the effects of neurotransmitters on HCN channels and their corresponding intracellular mechanisms. We also discuss the dysregulation of HCN channels in pathological conditions. Finally, insight into future directions in this exciting area of ion channel research is provided.

  20. Identification of Protein Interactions Involved in Cellular Signaling

    PubMed Central

    Westermarck, Jukka; Ivaska, Johanna; Corthals, Garry L.

    2013-01-01

    Protein-protein interactions drive biological processes. They are critical for all intra- and extracellular functions, and the technologies to analyze them are widely applied throughout the various fields of biological sciences. This study takes an in-depth view of some common principles of cellular regulation and provides a detailed account of approaches required to comprehensively map signaling protein-protein interactions in any particular cellular system or condition. We provide a critical review of the benefits and disadvantages of the yeast two-hybrid method and affinity purification coupled with mass spectrometric procedures for identification of signaling protein-protein interactions. In particular, we emphasize the quantitative and qualitative differences between tandem affinity and one-step purification (such as FLAG and Strep tag) methods. Although applicable to all types of interaction studies, a special section is devoted in this review to aspects that should be considered when attempting to identify signaling protein interactions that often are transient and weak by nature. Finally, we discuss shotgun and quantitative information that can be gleaned by MS-coupled methods for analysis of multiprotein complexes. PMID:23481661

  1. Papillomavirus sequences integrate near cellular oncogenes in some cervical carcinomas

    SciTech Connect

    Duerst, M.; Croce, C.M.; Gissmann, L.; Schwarz, E.; Huebner, K.

    1987-02-01

    The chromosomal locations of cellular sequences flanking integrated papillomavirus DNA in four cervical cell lines and a primary cervical carcinoma have been determined. The two human papillomavirus (HPV) 16 flanking sequences derived from the tumor were localized to chromosomes regions 20pter..-->..20q13 and 3p25..-->..3qter, regions that also contain the protooncogenes c-src-1 and c-raf-1, respectively. The HPV 16 integration site in the SiHa cervical carcinoma-derived cell line is in chromosome region 13q14..-->..13q32. The HPV 18 integration site in SW756 cervical carcinoma cells is in chromosome 12 but is not closely linked to the Ki-ras2 gene. Finally, in two cervical carcinoma cell lines, HeLa and C4-I, HPV 18 DNA is integrated in chromosome 8, 5' of the c-myc gene. The HeLaHPV 18 integration site is within 40 kilobases 5' of the c-myc gene, inside the HL60 amplification unit surrounding and including the c-myc gene. Additionally, steady-state levels of c-myc mRNA are elevated in HeLa and C4-I cells relative to other cervical carcinoma cell lines. Thus, in at least some genital tumors, cis-activation of cellular oncogenes by HPV may be involved in malignant transformation of cervical cells.

  2. Force field parameters for S-nitrosocysteine and molecular dynamics simulations of S-nitrosated thioredoxin.

    PubMed

    Han, Sanghwa

    2008-12-12

    Estimation of structural perturbation induced by S-nitrosation is important to understand the mode of cellular signal transduction mediated by nitric oxide. Crystal structures of S-nitrosated proteins have been solved only for a few cases, however, so that molecular dynamics simulation may provide an alternative tool for probing structural perturbation. In this study AMBER-99 force field parameters for S-nitrosocysteine were developed and applied to molecular dynamics simulations of S-nitrosated thioredoxin. Geometry optimization at the level of HF/6-31G * was followed by a restrained electrostatic potential charge-fitting to obtain the atomic charges of S-nitrosocysteine. Force constants for bonds and angles were obtained from generalized AMBER force field. Torsional force constants for CC-SN and CS-NO were determined by fitting the torsional profiles obtained from geometry optimization with those from molecular mechanical energy minimization. Finally molecular dynamics simulations were performed with theses parameters on oxidized and reduced thioredoxin with and without S-nitrosocysteine. In all cases the root-mean-square deviations of alpha-carbons yielded well-behaved trajectories. The CC-SH dihedral angle which fluctuated severely during the simulation became quiet upon S-nitrosation. In conclusion the force field parameters developed in this study for S-nitrosocysteine appear to be suitable for molecular dynamics simulations of S-nitrosated proteins.

  3. Integrated semiconductor optical sensors for cellular and neural imaging.

    PubMed

    Levi, Ofer; Lee, Thomas T; Lee, Meredith M; Smith, Stephen J; Harris, James S

    2007-04-01

    We review integrated optical sensors for functional brain imaging, localized index-of-refraction sensing as part of a lab-on-a-chip, and in vivo continuous monitoring of tumor and cancer stem cells. We present semiconductor-based sensors and imaging systems for these applications. Measured intrinsic optical signals and tissue optics simulations indicate the need for high dynamic range and low dark-current neural sensors. Simulated and measured reflectance spectra from our guided resonance filter demonstrate the capability for index-of-refraction sensing on cellular scales, compatible with integrated biosensors. Finally, we characterized a thermally evaporated emission filter that can be used to improve sensitivity for in vivo fluorescence sensing.

  4. What can we hope for from cellular automata?

    NASA Astrophysics Data System (ADS)

    Doolen, Gary

    Although the idea of using discrete methods for modeling partial differential equations occured very early, the actual statement that cellular automata techniques can approximate the solutions of hydrodynamic partial differential equations was first discovered by Frisch, Hasslacher, and Pomeau. Their description of the derivation, which assumes the validity of the Boltzmann equation, appeared in the Physical Review Letters in April 1986. It is the intent of this article to provide a description of the simplest lattice gas model and to examine the successes and inadequacies of a lattice gas calculation of flow in a two-dimensional channel. Some comments will summarize a recent result of a lattice gas simulation of flow through porous media, a problem which is ideal for the lattice gas method. Finally, some remarks will be focused on the impressive speeds which could be obtained from a dedicated lattice gas computer.

  5. A coarse-grained model for the simulations of biomolecular interactions in cellular environments

    SciTech Connect

    Xie, Zhong-Ru; Chen, Jiawen; Wu, Yinghao

    2014-02-07

    The interactions of bio-molecules constitute the key steps of cellular functions. However, in vivo binding properties differ significantly from their in vitro measurements due to the heterogeneity of cellular environments. Here we introduce a coarse-grained model based on rigid-body representation to study how factors such as cellular crowding and membrane confinement affect molecular binding. The macroscopic parameters such as the equilibrium constant and the kinetic rate constant are calibrated by adjusting the microscopic coefficients used in the numerical simulations. By changing these model parameters that are experimentally approachable, we are able to study the kinetic and thermodynamic properties of molecular binding, as well as the effects caused by specific cellular environments. We investigate the volumetric effects of crowded intracellular space on bio-molecular diffusion and diffusion-limited reactions. Furthermore, the binding constants of membrane proteins are currently difficult to measure. We provide quantitative estimations about how the binding of membrane proteins deviates from soluble proteins under different degrees of membrane confinements. The simulation results provide biological insights to the functions of membrane receptors on cell surfaces. Overall, our studies establish a connection between the details of molecular interactions and the heterogeneity of cellular environments.

  6. Cellular behavior in micropatterned hydrogels by bioprinting system depended on the cell types and cellular interaction.

    PubMed

    Hong, Soyoung; Song, Seung-Joon; Lee, Jae Yeon; Jang, Hwanseok; Choi, Jaesoon; Sun, Kyung; Park, Yongdoo

    2013-08-01

    The fabrication of patterned microstructures within three-dimensional (3D) matrices is a challenging subject in tissue engineering and regenerative medicine. A 3D, free-moving bioprinting system was developed and hydrogels were patterned by varying the process parameters of z-axis moving velocity and ejection velocity. The patterning of hydrogel based microfibers in a 3D matrigel was achieved with dimensions of 4.5 mm length and widths from 79 to 200 μm. Hyaluronan-based hydrogels mixed with fibroblasts (L929), mouse endothelial cells (MS1), or human mesenchymal stem cells (hMSCs) were patterned using a 3D moving axis bioprinter and cell behavior was monitored in culture for up to 16 days. L929 and MS1 cells and hMSCs in patterned hydrogel revealed cell-cell interactions and a morphological dependency on cell types. HMSCs formed spheres through cell aggregation, while L929 cells increased in cellular mass without cell aggregation and MS1 dispersed into the matrix instead of aggregating. The aggregation of hMSCs was attenuated by treatment with Rho kinase (ROCK) inhibitor and cadherin antibody. This reflected the close relationship between cell aggregation and migration with RhoA and cell-cell adhesion molecules. Angiogenic-specific gene expression profiles showed that expression of CD105 decreased to 22% in the ROCK inhibitor group compared to control group. These results showed that cell-based patterns in a 3D matrix are highly dependent on both cell aggregation and migration over time.

  7. Relations between demographic parameters.

    PubMed

    Demetrius, L

    1979-05-01

    The mean life-expectancy e describes the average prospective life-time of an individual aged zero. This parameter can be explicitly described in terms of the survivorship distribution of the population. The Malthusian parameter r represents the asymptotic growth rate of a population. This parameter can be implicitly expressed in terms of the net-maternity distribution. The parameters e and r incompletely incorporate the age-specific fertility and mortality pattern of a population; distinct populations may have the same growth rate but different net-maternity functions; distinct populations may be characterized by the same mean life expectation but may have different survivorship distributions. This article analyzes a class of parameters called the entropy of a population (Demetrius, 1974a) which distinguishes between net-maternity functions with the same growth rate and also mortality distributions with the same mean life expectation. This class of parameters measures the convexity of the fertility and mortality distributions. This paper analyzes the relations between the entropy parameter and the standard demographic parameters.

  8. LTFT Operating Parameters

    SciTech Connect

    Brown, Donald W.; Albright, James N.

    1989-04-18

    In order to finalize planning, the following specifications are recommended for the operation of the LTFT. Although operation of the reservoir under the specified conditions provides for a comprehensive evaluation of the Phase II reservoir.

  9. Gravimelt Process development. Final report

    SciTech Connect

    Not Available

    1983-06-01

    This final report contains the results of a bench-scale program to continue the development of the TRW proprietary Gravimelt Process for chemically cleaning coal. This project consisted of two major efforts, a laboratory study aimed at identifying parameters which would influence the operation of a bench unit for desulfurization and demineralization of coal and the design, construction and operation of two types of continuous plug-flow type bench-scale fused caustic leachers. This present bench scale project has demonstrated modes for the continuous operation of fused caustic leaching of coal at coal throughputs of 1 to 5 pounds per hour. The remaining process unit operations of leach solutions regeneration and coal washing and filtration should be tested at bench scale together with fused caustic leaching of coal to demonstrate the complete Gravimelt Process. 22 figures, 11 tables.

  10. Calibrating floor field cellular automaton models for pedestrian dynamics by using likelihood function optimization

    NASA Astrophysics Data System (ADS)

    Lovreglio, Ruggiero; Ronchi, Enrico; Nilsson, Daniel

    2015-11-01

    The formulation of pedestrian floor field cellular automaton models is generally based on hypothetical assumptions to represent reality. This paper proposes a novel methodology to calibrate these models using experimental trajectories. The methodology is based on likelihood function optimization and allows verifying whether the parameters defining a model statistically affect pedestrian navigation. Moreover, it allows comparing different model specifications or the parameters of the same model estimated using different data collection techniques, e.g. virtual reality experiment, real data, etc. The methodology is here implemented using navigation data collected in a Virtual Reality tunnel evacuation experiment including 96 participants. A trajectory dataset in the proximity of an emergency exit is used to test and compare different metrics, i.e. Euclidean and modified Euclidean distance, for the static floor field. In the present case study, modified Euclidean metrics provide better fitting with the data. A new formulation using random parameters for pedestrian cellular automaton models is also defined and tested.

  11. Cellular Satellites: Joint Communications With Integrated Acquisition

    DTIC Science & Technology

    2015-04-01

    cellphone towers in space, providing smartphone-like service that keeps users connected while on the move and in challenging urban , jungle or mountainous...vice, even in remote regions, urban environments or inclem- ent weather. By combining satellites with cellular technology, MUOS will provide troops

  12. Cellular Learning: Strategy for the Future.

    ERIC Educational Resources Information Center

    Schrum, John

    1987-01-01

    Cellular learning refers to both arrangement of shop equipment and addition of new course materials for a contemporary manufacturing curriculum. The concept is an accumulation of ideas and strategies for the instruction and training of students. It also provides a method for consolidating old equipment and adding group technology. (CH)

  13. Cellular Potts Models of Fruit Fly Embryogenesis

    NASA Astrophysics Data System (ADS)

    Rohner, Jason; Hutson, Shane

    2006-11-01

    Biologists have extensively studied embryonic development in the fruit fly (Drosophila melangaster) as a model for morphogenesis. Our overall goal is to understand how the cellular rearrangements of morphogenesis are caused by the underlying forces between cells. To that end, we are developing means to replicate fruit fly embryogenesis (from cellular differentiation to dorsal closure) using cellular Potts models. Cells are described as collections of like ``spins''; and spin-spin interaction energies are used to describe the forces along cell boundaries. Using a four state (spin-type) model (three tissue types and the surrounding media) we have reproduced cell sorting as well as engulfment of a surface grouping of tissue. Cell sorting can be accomplished using only the spin-spin interaction energies with the volume components being used only for cell size management. We are currently attempting to replicate the experimentally determined geometry and dynamics of dorsal closure. This modeling will take advantage of software tools developed at Notre Dame for looking at cellular Potts models and packaged as CompuCell3D.

  14. Fuzzy cellular automata models in immunology

    SciTech Connect

    Ahmed, E.

    1996-10-01

    The self-nonself character of antigens is considered to be fuzzy. The Chowdhury et al. cellular automata model is generalized accordingly. New steady states are found. The first corresponds to a below-normal help and suppression and is proposed to be related to autoimmune diseases. The second corresponds to a below-normal B-cell level.

  15. The development of hippocampal cellular assemblies.

    PubMed

    Li, Guangnan; Pleasure, Samuel J

    2014-01-01

    The proper assembly of a cohort of distinct cell types is a prerequisite for building a functional hippocampus. In this review, we describe the major molecular events of the developmental program leading to the cellular construction of the hippocampus. Data from rodent studies are used here to elaborate on our understanding of these processes.

  16. A Quantum Relativistic Prisoner's Dilemma Cellular Automaton

    NASA Astrophysics Data System (ADS)

    Alonso-Sanz, Ramón; Carvalho, Márcio; Situ, Haozhen

    2016-10-01

    The effect of variable entangling on the dynamics of a spatial quantum relativistic formulation of the iterated prisoner's dilemma game is studied in this work. The game is played in the cellular automata manner, i.e., with local and synchronous interaction. The game is assessed in fair and unfair contests.

  17. Failure probability under parameter uncertainty.

    PubMed

    Gerrard, R; Tsanakas, A

    2011-05-01

    In many problems of risk analysis, failure is equivalent to the event of a random risk factor exceeding a given threshold. Failure probabilities can be controlled if a decisionmaker is able to set the threshold at an appropriate level. This abstract situation applies, for example, to environmental risks with infrastructure controls; to supply chain risks with inventory controls; and to insurance solvency risks with capital controls. However, uncertainty around the distribution of the risk factor implies that parameter error will be present and the measures taken to control failure probabilities may not be effective. We show that parameter uncertainty increases the probability (understood as expected frequency) of failures. For a large class of loss distributions, arising from increasing transformations of location-scale families (including the log-normal, Weibull, and Pareto distributions), the article shows that failure probabilities can be exactly calculated, as they are independent of the true (but unknown) parameters. Hence it is possible to obtain an explicit measure of the effect of parameter uncertainty on failure probability. Failure probability can be controlled in two different ways: (1) by reducing the nominal required failure probability, depending on the size of the available data set, and (2) by modifying of the distribution itself that is used to calculate the risk control. Approach (1) corresponds to a frequentist/regulatory view of probability, while approach (2) is consistent with a Bayesian/personalistic view. We furthermore show that the two approaches are consistent in achieving the required failure probability. Finally, we briefly discuss the effects of data pooling and its systemic risk implications.

  18. Multiscale Model of Colorectal Cancer Using the Cellular Potts Framework

    PubMed Central

    Osborne, James M

    2015-01-01

    Colorectal cancer (CRC) is one of the major causes of death in the developed world and forms a canonical example of tumorigenesis. CRC arises from a string of mutations of individual cells in the colorectal crypt, making it particularly suited for multiscale multicellular modeling, where mutations of individual cells can be clearly represented and their effects readily tracked. In this paper, we present a multicellular model of the onset of colorectal cancer, utilizing the cellular Potts model (CPM). We use the model to investigate how, through the modification of their mechanical properties, mutant cells colonize the crypt. Moreover, we study the influence of mutations on the shape of cells in the crypt, suggesting possible cell- and tissue-level indicators for identifying early-stage cancerous crypts. Crucially, we discuss the effect that the motility parameters of the model (key factors in the behavior of the CPM) have on the distribution of cells within a homeostatic crypt, resulting in an optimal parameter regime that accurately reflects biological assumptions. In summary, the key results of this paper are 1) how to couple the CPM with processes occurring on other spatial scales, using the example of the crypt to motivate suitable motility parameters; 2) modeling mutant cells with the CPM; 3) and investigating how mutations influence the shape of cells in the crypt. PMID:26461973

  19. Kinetics of the cellular decomposition of supersaturated solid solutions

    NASA Astrophysics Data System (ADS)

    Ivanov, M. A.; Naumuk, A. Yu.

    2014-09-01

    A consistent description of the kinetics of the cellular decomposition of supersaturated solid solutions with the development of a spatially periodic structure of lamellar (platelike) type, which consists of alternating phases of precipitates on the basis of the impurity component and depleted initial solid solution, is given. One of the equations, which determines the relationship between the parameters that describe the process of decomposition, has been obtained from a comparison of two approaches in order to determine the rate of change in the free energy of the system. The other kinetic parameters can be described with the use of a variational method, namely, by the maximum velocity of motion of the decomposition boundary at a given temperature. It is shown that the mutual directions of growth of the lamellae of different phases are determined by the minimum value of the interphase surface energy. To determine the parameters of the decomposition, a simple thermodynamic model of states with a parabolic dependence of the free energy on the concentrations has been used. As a result, expressions that describe the decomposition rate, interlamellar distance, and the concentration of impurities in the phase that remain after the decomposition have been derived. This concentration proves to be equal to the half-sum of the initial concentration and the equilibrium concentration corresponding to the decomposition temperature.

  20. Decisions on the fly in cellular sensory systems

    PubMed Central

    Siggia, Eric D.; Vergassola, Massimo

    2013-01-01

    Cells send and receive signals through pathways that have been defined in great detail biochemically, and it is often presumed that the signals convey only level information. Cell signaling in the presence of noise is extensively studied but only rarely is the speed required to make a decision considered. However, in the immune system, rapidly developing embryos, and cellular response to stress, fast and accurate actions are required. Statistical theory under the rubric of “exploit–explore” quantifies trade-offs between decision speed and accuracy and supplies rigorous performance bounds and algorithms that realize them. We show that common protein phosphorylation networks can implement optimal decision theory algorithms and speculate that the ubiquitous chemical modifications to receptors during signaling actually perform analog computations. We quantify performance trade-offs when the cellular system has incomplete knowledge of the data model. For the problem of sensing the time when the composition of a ligand mixture changes, we find a nonanalytic dependence on relative concentrations and specify the number of parameters needed for near-optimal performance and how to adjust them. The algorithms specify the minimal computation that has to take place on a single receptor before the information is pooled across the cell. PMID:24019464

  1. Experimental design for dynamics identification of cellular processes.

    PubMed

    Dinh, Vu; Rundell, Ann E; Buzzard, Gregery T

    2014-03-01

    We address the problem of using nonlinear models to design experiments to characterize the dynamics of cellular processes by using the approach of the Maximally Informative Next Experiment (MINE), which was introduced in W. Dong et al. (PLoS ONE 3(8):e3105, 2008) and independently in M.M. Donahue et al. (IET Syst. Biol. 4:249-262, 2010). In this approach, existing data is used to define a probability distribution on the parameters; the next measurement point is the one that yields the largest model output variance with this distribution. Building upon this approach, we introduce the Expected Dynamics Estimator (EDE), which is the expected value using this distribution of the output as a function of time. We prove the consistency of this estimator (uniform convergence to true dynamics) even when the chosen experiments cluster in a finite set of points. We extend this proof of consistency to various practical assumptions on noisy data and moderate levels of model mismatch. Through the derivation and proof, we develop a relaxed version of MINE that is more computationally tractable and robust than the original formulation. The results are illustrated with numerical examples on two nonlinear ordinary differential equation models of biomolecular and cellular processes.

  2. Screening the Cellular Microenvironment: A Role for Microfluidics

    PubMed Central

    Warrick, Jay W.; Murphy, William L.; Beebe, David J.

    2010-01-01

    The cellular microenvironment is an increasingly discussed topic in cell biology as it has been implicated in the progression of cancer and the maintenance of stem cells. The microenvironment of a cell is an organized combination of extracellular matrix (ECM), cells, and interstitial fluid that influence cellular phenotype through physical, mechanical, and biochemical mechanisms. Screening can be used to map combinations of cells and microenvironments to phenotypic outcomes in a way that can help develop more predictive in vitro models and to better understand phenotypic mechanisms from a systems biology perspective. This paper examines microenvironmental screening in terms of outcomes and benefits, key elements of the screening process, challenges for implementation, and a possible role for microfluidics as the screening platform. To assess microfluidics for use in microenvironmental screening, examples and categories of micro-scale and microfluidic technology are highlighted. Microfluidic technology shows promise for simultaneous control of multiple parameters of the microenvironment and can provide a base for scaling advanced cell-based experiments into automated high-throughput formats. PMID:20190880

  3. The inherent cellular radiosensitivity of epithelial ovarian carcinoma

    SciTech Connect

    Rotmensch, J.; Schwartz, J.L.; Atcher, R.W.; Grdina, D.J.; Toohill, M.; Weichselbaum, R.W. )

    1989-12-01

    Ovarian carcinomas of similar histology have variable responses to radiation therapy. It has been suggested that inherent cellular resistance to radiation may in part underlie radiotherapy failure. To determine in vitro radiobiological parameters of papillary serous adenocarcinoma of the ovary, we investigated the cellular responses of 16 early-passage ovarian carcinoma cell lines to radiation. The radiosensitivity, as measured by D0, ranged from 1.05 to 2.40 Gy (mean 1.70 Gy), and, as measured by D, ranged from 1.65 to 3.54 Gy (mean 2.38 Gy). The extrapolation number -n ranged from 1.1 to 2.0 (mean 1.5). The cells had a 1.3- to 5.4-fold (mean 2.8) ability to recover from potential lethal damage (PLDR) 24 hr after irradiation and subculture from plateau-phase cultures. Their inherent radioresistance may be one factor in the failure of some ovarian cancers to be sterilized by radiation.

  4. Cellular Automaton Simulation of Vegetated Dune Field Dynamics

    NASA Astrophysics Data System (ADS)

    Nield, J. M.; Baas, A. C.

    2007-12-01

    Vegetated aeolian dune fields develop through non-linear interactions between physical geomorphic processes and ecological vegetation growth and response into complex ecogeomorphic systems that are sensitive to both climatic and environmental variations. We present a Discrete Ecogeomorphic Aeolian Landscape (DECAL) cellular automaton model that replicates the self-organisation of vegetated dune systems and enables the investigation of conditions necessary for long-walled (hairpin) parabolic dune and nebkha formation in coastal and semi-arid environments over various temporal and spatial scales. The algorithm utilises simple transport rules and mutual feedback between geomorphic and ecological components to investigate vegetation pattern formation and how and why this influences dune dynamics. We examine ecogeomorphic interactions both by exploring system mechanics via dune mobility and by more descriptive numerical state variables, facilitating the investigation of trajectories and potential attractors as a function of environmental parameters and system perturbations and leading to the identification of possible system sensitivities and thresholds. The model simulations elucidate possible dune field responses to anthropogenic impacts and palaeo and future climate variations and highlight the ability of vegetation to impart a characteristic length-scale on a landscape. This simple vegetated dune model illustrates the power and versatility of a cellular automaton approach for exploring ecological and geomorphic interactions in complex earth surface systems.

  5. Cellular circadian clocks in mood disorders.

    PubMed

    McCarthy, Michael J; Welsh, David K

    2012-10-01

    Bipolar disorder (BD) and major depressive disorder (MDD) are heritable neuropsychiatric disorders associated with disrupted circadian rhythms. The hypothesis that circadian clock dysfunction plays a causal role in these disorders has endured for decades but has been difficult to test and remains controversial. In the meantime, the discovery of clock genes and cellular clocks has revolutionized our understanding of circadian timing. Cellular circadian clocks are located in the suprachiasmatic nucleus (SCN), the brain's primary circadian pacemaker, but also throughout the brain and peripheral tissues. In BD and MDD patients, defects have been found in SCN-dependent rhythms of body temperature and melatonin release. However, these are imperfect and indirect indicators of SCN function. Moreover, the SCN may not be particularly relevant to mood regulation, whereas the lateral habenula, ventral tegmentum, and hippocampus, which also contain cellular clocks, have established roles in this regard. Dysfunction in these non-SCN clocks could contribute directly to the pathophysiology of BD/MDD. We hypothesize that circadian clock dysfunction in non-SCN clocks is a trait marker of mood disorders, encoded by pathological genetic variants. Because network features of the SCN render it uniquely resistant to perturbation, previous studies of SCN outputs in mood disorders patients may have failed to detect genetic defects affecting non-SCN clocks, which include not only mood-regulating neurons in the brain but also peripheral cells accessible in human subjects. Therefore, reporters of rhythmic clock gene expression in cells from patients or mouse models could provide a direct assay of the molecular gears of the clock, in cellular clocks that are likely to be more representative than the SCN of mood-regulating neurons in patients. This approach, informed by the new insights and tools of modern chronobiology, will allow a more definitive test of the role of cellular circadian clocks

  6. Cellular recognition of synthetic peptide amphiphiles in supported bioartificial membranes

    NASA Astrophysics Data System (ADS)

    Pakalns, Teika

    The goal of this study was to demonstrate that lipidated cell adhesion peptides could form well-ordered biomimetic surfaces that were capable of influencing cellular behavior in a controlled and specific manner. The first step taken was to covalently link synthetic dialkyl tails to the amino-termini of the collagen-derived peptide IV-H1 (amino acid sequence GVKGDKGNPGWPGAP) and the well-known tripeptide Arg-Gly-Asp (RGD) to produce amino-coupled peptide amphiphiles. Other spatial orientations of RGD were also generated by coupling tails to the carboxyl-terminus to give carboxyl-coupled RGD amphiphiles and to both the amino- and carboxyl-termini to give looped RGD amphiphiles. The next step taken was to let the peptide amphiphile self-assemble along with methyl ester-capped dialkyl tails into mixed films. It was found that all the peptide amphiphiles formed stable monolayers at the air-water interface in a Langmuir trough. IV-H1 amphiphiles and carboxyl-coupled and looped RGD amphiphiles deposited well as Langmuir-Blodgett mixed films on solid surfaces at all peptide concentrations, but aminocoupled RGD amphiphiles did not deposit well at high RGD concentrations. FT-IR studies of films containing RGD amphiphiles showed that amino-coupled RGD head groups formed the strongest lateral hydrogen bonds. The final step was to study cellular response to mixed films containing IV-H1 or RGD amphiphiles. The spreading of melanoma cells was influenced by both the molar concentration and spatial orientation of the amphiphilic peptides. Cells spread on IV-H1 and looped RGD films in a concentration-dependent manner, but spread indiscriminately on carboxyl-coupled RGD films and did not spread at all on well-deposited amino-coupled RGD films. The specificity of the cellular response to looped RGD amphiphiles was investigated. Control films of looped Arg-Gly-Glu (RGE) amphiphiles inhibited the adhesion and spreading of melanoma and endothelial cells, and antibody inhibition of the

  7. Acidosis induces reprogramming of cellular metabolism to mitigate oxidative stress

    PubMed Central

    2013-01-01

    Background A variety of oncogenic and environmental factors alter tumor metabolism to serve the distinct cellular biosynthetic and bioenergetic needs present during oncogenesis. Extracellular acidosis is a common microenvironmental stress in solid tumors, but little is known about its metabolic influence, particularly when present in the absence of hypoxia. In order to characterize the extent of tumor cell metabolic adaptations to acidosis, we employed stable isotope tracers to examine how acidosis impacts glucose, glutamine, and palmitate metabolism in breast cancer cells exposed to extracellular acidosis. Results Acidosis increased both glutaminolysis and fatty acid β-oxidation, which contribute metabolic intermediates to drive the tricarboxylic acid cycle (TCA cycle) and ATP generation. Acidosis also led to a decoupling of glutaminolysis and novel glutathione (GSH) synthesis by repressing GCLC/GCLM expression. We further found that acidosis redirects glucose away from lactate production and towards the oxidative branch of the pentose phosphate pathway (PPP). These changes all serve to increase nicotinamide adenine dinucleotide phosphate (NADPH) production and counter the increase in reactive oxygen species (ROS) present under acidosis. The reduced novel GSH synthesis under acidosis may explain the increased demand for NADPH to recycle existing pools of GSH. Interestingly, acidosis also disconnected novel ribose synthesis from the oxidative PPP, seemingly to reroute PPP metabolites to the TCA cycle. Finally, we found that acidosis activates p53, which contributes to both the enhanced PPP and increased glutaminolysis, at least in part, through the induction of G6PD and GLS2 genes. Conclusions Acidosis alters the cellular metabolism of several major metabolites, which induces a significant degree of metabolic inflexibility. Cells exposed to acidosis largely rely upon mitochondrial metabolism for energy generation to the extent that metabolic intermediates are

  8. Mosquito population dynamics from cellular automata-based simulation

    NASA Astrophysics Data System (ADS)

    Syafarina, Inna; Sadikin, Rifki; Nuraini, Nuning

    2016-02-01

    In this paper we present an innovative model for simulating mosquito-vector population dynamics. The simulation consist of two stages: demography and dispersal dynamics. For demography simulation, we follow the existing model for modeling a mosquito life cycles. Moreover, we use cellular automata-based model for simulating dispersal of the vector. In simulation, each individual vector is able to move to other grid based on a random walk. Our model is also capable to represent immunity factor for each grid. We simulate the model to evaluate its correctness. Based on the simulations, we can conclude that our model is correct. However, our model need to be improved to find a realistic parameters to match real data.

  9. A cellular automaton model for evacuation flow using game theory

    NASA Astrophysics Data System (ADS)

    Guan, Junbiao; Wang, Kaihua; Chen, Fangyue

    2016-11-01

    Game theory serves as a good tool to explore crowd dynamic conflicts during evacuation processes. The purpose of this study is to simulate the complicated interaction behavior among the conflicting pedestrians in an evacuation flow. Two types of pedestrians, namely, defectors and cooperators, are considered, and two important factors including fear index and cost coefficient are taken into account. By combining the snowdrift game theory with a cellular automaton (CA) model, it is shown that the increase of fear index and cost coefficient will lengthen the evacuation time, which is more apparent for large values of cost coefficient. Meanwhile, it is found that the defectors to cooperators ratio could always tend to consistent states despite different values of parameters, largely owing to self-organization effects.

  10. Telomeres and lifestyle factors: roles in cellular aging.

    PubMed

    Lin, Jue; Epel, Elissa; Blackburn, Elizabeth

    2012-02-01

    Recent research has demonstrated that telomere maintenance might be a key integrating point for the cumulative effects of genetic, environmental and lifestyle factors on aging and aging-related diseases. It is timely to 'take stock' of where this work has led the field. This review summarizes studies that have examined associations between lifestyle factors and telomere length and telomerase activity. In most of the studies described in this chapter, telomere length was measured in leukocytes (LTL) or peripheral blood mononuclear cells (PBMCs), taken from blood draws from the study subjects. Much of this chapter focuses on psychological stress, a widespread factor often intimately tied in with lifestyle or behavioral factors that in turn are related to risks of clinical diseases. Together, these findings suggest that cellular aging is linked to a range of influences, with an individual's life events and lifestyle parameters playing significant roles. Lastly, we propose possible biochemical mechanisms that mediate these associations and discuss future directions.

  11. Dichotomy of cellular inhibition by small-molecule inhibitors revealed by single-cell analysis

    PubMed Central

    Vogel, Robert M.; Erez, Amir; Altan-Bonnet, Grégoire

    2016-01-01

    Despite progress in drug development, a quantitative and physiological understanding of how small-molecule inhibitors act on cells is lacking. Here, we measure the signalling and proliferative response of individual primary T-lymphocytes to a combination of antigen, cytokine and drug. We uncover two distinct modes of signalling inhibition: digital inhibition (the activated fraction of cells diminishes upon drug treatment, but active cells appear unperturbed), versus analogue inhibition (the activated fraction is unperturbed whereas activation response is diminished). We introduce a computational model of the signalling cascade that accounts for such inhibition dichotomy, and test the model predictions for the phenotypic variability of cellular responses. Finally, we demonstrate that the digital/analogue dichotomy of cellular response as revealed on short (signal transduction) timescales, translates into similar dichotomy on longer (proliferation) timescales. Our single-cell analysis of drug action illustrates the strength of quantitative approaches to translate in vitro pharmacology into functionally relevant cellular settings. PMID:27687249

  12. Dichotomy of cellular inhibition by small-molecule inhibitors revealed by single-cell analysis

    NASA Astrophysics Data System (ADS)

    Vogel, Robert M.; Erez, Amir; Altan-Bonnet, Grégoire

    2016-09-01

    Despite progress in drug development, a quantitative and physiological understanding of how small-molecule inhibitors act on cells is lacking. Here, we measure the signalling and proliferative response of individual primary T-lymphocytes to a combination of antigen, cytokine and drug. We uncover two distinct modes of signalling inhibition: digital inhibition (the activated fraction of cells diminishes upon drug treatment, but active cells appear unperturbed), versus analogue inhibition (the activated fraction is unperturbed whereas activation response is diminished). We introduce a computational model of the signalling cascade that accounts for such inhibition dichotomy, and test the model predictions for the phenotypic variability of cellular responses. Finally, we demonstrate that the digital/analogue dichotomy of cellular response as revealed on short (signal transduction) timescales, translates into similar dichotomy on longer (proliferation) timescales. Our single-cell analysis of drug action illustrates the strength of quantitative approaches to translate in vitro pharmacology into functionally relevant cellular settings.

  13. Parameter estimating state reconstruction

    NASA Technical Reports Server (NTRS)

    George, E. B.

    1976-01-01

    Parameter estimation is considered for systems whose entire state cannot be measured. Linear observers are designed to recover the unmeasured states to a sufficient accuracy to permit the estimation process. There are three distinct dynamics that must be accommodated in the system design: the dynamics of the plant, the dynamics of the observer, and the system updating of the parameter estimation. The latter two are designed to minimize interaction of the involved systems. These techniques are extended to weakly nonlinear systems. The application to a simulation of a space shuttle POGO system test is of particular interest. A nonlinear simulation of the system is developed, observers designed, and the parameters estimated.

  14. FINAL SCIENTIFIC/TECHNICAL REPORT

    SciTech Connect

    Satish Mohapatra

    2011-12-21

    Dynalene Inc has developed and patented a fuel cell coolant with the help of DOE SBIR Phase I and Phase II funding (Project DE-FG02-04ER83884). However, this coolant could only be produced in lab scale (500 ml to 2 L) due to problems in the optimization and scale-up of a nanoparticle ingredient. This project optimized the nanoparticle production process in 10 L and 100 L reactors (which translates to about 5000 gallons of coolant), optimized the filtration process for the nanoparticles, and develop a high throughput production as well as quality control method for the final coolant formulation. Scale-up of nanoparticle synthesis (using emulsion polymerization) is an extremely challenging task. Dynalene researchers, in collaboration with a university partner, identified all the parameters affecting the size, charge density and coagulation characteristics of the nanoparticles and then optimized these parameters to achieve the goals and the objectives of this project. Nanoparticle synthesis was demonstrated to be reproducible in the 10 L and 100 L scales.

  15. Quality Matters: Systematic Analysis of Endpoints Related to "Cellular Life" in Vitro Data of Radiofrequency Electromagnetic Field Exposure.

    PubMed

    Simkó, Myrtill; Remondini, Daniel; Zeni, Olga; Scarfi, Maria Rosaria

    2016-07-12

    Possible hazardous effects of radiofrequency electromagnetic fields (RF-EMF) at low exposure levels are controversially discussed due to inconsistent study findings. Therefore, the main focus of the present study is to detect if any statistical association exists between RF-EMF and cellular responses, considering cell proliferation and apoptosis endpoints separately and with both combined as a group of "cellular life" to increase the statistical power of the analysis. We searched for publications regarding RF-EMF in vitro studies in the PubMed database for the period 1995-2014 and extracted the data to the relevant parameters, such as cell culture type, frequency, exposure duration, SAR, and five exposure-related quality criteria. These parameters were used for an association study with the experimental outcome in terms of the defined endpoints. We identified 104 published articles, from which 483 different experiments were extracted and analyzed. Cellular responses after exposure to RF-EMF were significantly associated to cell lines rather than to primary cells. No other experimental parameter was significantly associated with cellular responses. A highly significant negative association with exposure condition-quality and cellular responses was detected, showing that the more the quality criteria requirements were satisfied, the smaller the number of detected cellular responses. According to our knowledge, this is the first systematic analysis of specific RF-EMF bio-effects in association to exposure quality, highlighting the need for more stringent quality procedures for the exposure conditions.

  16. Quality Matters: Systematic Analysis of Endpoints Related to “Cellular Life” in Vitro Data of Radiofrequency Electromagnetic Field Exposure

    PubMed Central

    Simkó, Myrtill; Remondini, Daniel; Zeni, Olga; Scarfi, Maria Rosaria

    2016-01-01

    Possible hazardous effects of radiofrequency electromagnetic fields (RF-EMF) at low exposure levels are controversially discussed due to inconsistent study findings. Therefore, the main focus of the present study is to detect if any statistical association exists between RF-EMF and cellular responses, considering cell proliferation and apoptosis endpoints separately and with both combined as a group of “cellular life” to increase the statistical power of the analysis. We searched for publications regarding RF-EMF in vitro studies in the PubMed database for the period 1995–2014 and extracted the data to the relevant parameters, such as cell culture type, frequency, exposure duration, SAR, and five exposure-related quality criteria. These parameters were used for an association study with the experimental outcome in terms of the defined endpoints. We identified 104 published articles, from which 483 different experiments were extracted and analyzed. Cellular responses after exposure to RF-EMF were significantly associated to cell lines rather than to primary cells. No other experimental parameter was significantly associated with cellular responses. A highly significant negative association with exposure condition-quality and cellular responses was detected, showing that the more the quality criteria requirements were satisfied, the smaller the number of detected cellular responses. According to our knowledge, this is the first systematic analysis of specific RF-EMF bio-effects in association to exposure quality, highlighting the need for more stringent quality procedures for the exposure conditions. PMID:27420084

  17. Final Prep on SSME

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Alvin Pittman Sr., lead electronics technician with Pratt & Whitney Rocketdyne, and Janine Cuevas, a mechanical technician with PWR, perform final preparations on the space shuttle main engine tested Oct. 25, 2005, at NASA's Stennis Space Center. It was the first main engine test since Hurricane Katrina hit the Gulf Coast on Aug. 29.

  18. Final Technical Report

    SciTech Connect

    Gilbert, Chris

    2014-11-13

    The project, Capital Investment to Fund Equipment Purchases and Facility Modifications to Create a Sustainable Future for EnergyXchange served to replace landfill gas energy with alternative energy resources, primarily solar and wood waste. This is the final project closeout report.

  19. GENIE final state interactions

    SciTech Connect

    Dytman, Steven

    2015-10-15

    Final state interactions are an important component of any neutrino-nucleus Monte Carlo program. GENIE has 2 FSI programs which serve different purposes. Each has fair-good agreement with a wide range of hadron-nucleus data. Recent improvements and planned advancements are described.

  20. Rosetta: The Final Furlong

    NASA Astrophysics Data System (ADS)

    Wright, I. P.; Andrews, D. J.; Barber, S. J.; Sheridan, S.; Morgan, G. H.; Morse, A. D.

    2014-09-01

    By the time of the meeting, the Rosetta spacecraft will have formally arrived at its target comet, and final landing site selection will be in progress. One of the instruments that will be sent down to the surface of the comet is Ptolemy (a GC-MS).

  1. Final Technical Report

    SciTech Connect

    W. C. Griffith

    2007-01-01

    In this project we provide an example of how to develop multi-tiered models to go across levels of biological organization to provide a framework for relating results of studies of low doses of ionizing radiation. This framework allows us to better understand how to extrapolate laboratory results to policy decisions, and to identify future studies that will increase confidence in policy decisions. In our application of the conceptual Model we were able to move across multiple levels of biological assessment for rodents going from molecular to organism level for in vitro and in vivo endpoints and to relate these to human in vivo organism level effects. We used the rich literature on the effects of ionizing radiation on the developing brain in our models. The focus of this report is on disrupted neuronal migration due to radiation exposure and the structural and functional implications of these early biological effects. The cellular mechanisms resulting in pathogenesis are most likely due to a combination of the three mechanisms mentioned. For the purposes of a computational model, quantitative studies of low dose radiation effects on migration of neuronal progenitor cells in the cerebral mantle of experimental animals were used. In this project we were able to show now results from studies of low doses of radiation can be used in a multidimensional framework to construct linked models of neurodevelopment using molecular, cellular, tissue, and organ level studies conducted both in vitro and in vivo in rodents. These models could also be linked to behavioral endpoints in rodents which can be compared to available results in humans. The available data supported modeling to 10 cGy with limited data available at 5 cGy. We observed gradual but non-linear changes as the doses decreased. For neurodevelopment it appears that the slope of the dose response decreases from 25 cGy to 10 cGy. Future studies of neurodevelopment should be able to better define the dose response in

  2. Molecular and Cellular Effects Induced in Mytilus galloprovincialis Treated with Oxytetracycline at Different Temperatures

    PubMed Central

    Banni, Mohamed; Sforzini, Susanna; Franzellitti, Silvia; Oliveri, Caterina; Viarengo, Aldo; Fabbri, Elena

    2015-01-01

    The present study evaluatedthe interactive effects of temperature (16°C and 24°C) and a 4-day treatment with the antibiotic oxytetracycline (OTC) at 1 and 100μg/L on cellular and molecular parameters in the mussel Mytilus galloprovincialis. Lysosomal membrane stability (LMS), a sensitive biomarker of impaired health status in this organism, was assessed in the digestive glands. In addition, oxidative stress markers and the expression of mRNAs encoding proteins involved in antioxidant defense (catalase (cat) and glutathione-S-transferase (gst)) and the heat shock response (hsp90, hsp70, and hsp27) were evaluated in the gills, the target tissue of soluble chemicals. Finally, cAMP levels, which represent an important cell signaling pathway related to oxidative stress and the response to temperature challenges, were also determined in the gills. Exposure to heat stress as well as to OTC rendered a decrease in LMS and an increase in malonedialdehyde accumulation (MDA). CAT activity was not significantly modified, whereas GST activity decreased at 24°C. Cat and gst expression levels were reduced in animals kept at 24°C compared to 16°C in the presence or absence of OTC. At 16°C, treatment with OTC caused a significant increase in cat and gst transcript levels. Hsp27 mRNA was significantly up-regulated at all conditions compared to controls at 16°C. cAMP levels were increased at 24°C independent of the presence of OTC. PCA analysis showed that 37.21% and 25.89% of the total variance was explained by temperature and OTC treatment, respectively. Interestingly, a clear interaction was observed in animals exposed to both stressors increasing LMS and MDA accumulation and reducing hsp27 gene expression regulation. These interactions may suggest a risk for the organisms due to temperature increases in contaminated seawaters. PMID:26067465

  3. Experimentally calibrated population of models predicts and explains intersubject variability in cardiac cellular electrophysiology

    PubMed Central

    Britton, Oliver J.; Bueno-Orovio, Alfonso; Van Ammel, Karel; Lu, Hua Rong; Towart, Rob; Gallacher, David J.; Rodriguez, Blanca

    2013-01-01

    Cellular and ionic causes of variability in the electrophysiological activity of hearts from individuals of the same species are unknown. However, improved understanding of this variability is key to enable prediction of the response of specific hearts to disease and therapies. Limitations of current mathematical modeling and experimental techniques hamper our ability to provide insight into variability. Here, we describe a methodology to unravel the ionic determinants of intersubject variability exhibited in experimental recordings, based on the construction and calibration of populations of models. We illustrate the methodology through its application to rabbit Purkinje preparations, because of their importance in arrhythmias and safety pharmacology assessment. We consider a set of equations describing the biophysical processes underlying rabbit Purkinje electrophysiology, and we construct a population of over 10,000 models by randomly assigning specific parameter values corresponding to ionic current conductances and kinetics. We calibrate the model population by closely comparing simulation output and experimental recordings at three pacing frequencies. We show that 213 of the 10,000 candidate models are fully consistent with the experimental dataset. Ionic properties in the 213 models cover a wide range of values, including differences up to ±100% in several conductances. Partial correlation analysis shows that particular combinations of ionic properties determine the precise shape, amplitude, and rate dependence of specific action potentials. Finally, we demonstrate that the population of models calibrated using data obtained under physiological conditions quantitatively predicts the action potential duration prolongation caused by exposure to four concentrations of the potassium channel blocker dofetilide. PMID:23690584

  4. Diagnosis of cervical cells based on fractal and Euclidian geometrical measurements: Intrinsic Geometric Cellular Organization

    PubMed Central

    2014-01-01

    Background Fractal geometry has been the basis for the development of a diagnosis of preneoplastic and neoplastic cells that clears up the undetermination of the atypical squamous cells of undetermined significance (ASCUS). Methods Pictures of 40 cervix cytology samples diagnosed with conventional parameters were taken. A blind study was developed in which the clinic diagnosis of 10 normal cells, 10 ASCUS, 10 L-SIL and 10 H-SIL was masked. Cellular nucleus and cytoplasm were evaluated in the generalized Box-Counting space, calculating the fractal dimension and number of spaces occupied by the frontier of each object. Further, number of pixels occupied by surface of each object was calculated. Later, the mathematical features of the measures were studied to establish differences or equalities useful for diagnostic application. Finally, the sensibility, specificity, negative likelihood ratio and diagnostic concordance with Kappa coefficient were calculated. Results Simultaneous measures of the nuclear surface and the subtraction between the boundaries of cytoplasm and nucleus, lead to differentiate normality, L-SIL and H-SIL. Normality shows values less than or equal to 735 in nucleus surface and values greater or equal to 161 in cytoplasm-nucleus subtraction. L-SIL cells exhibit a nucleus surface with values greater than or equal to 972 and a subtraction between nucleus-cytoplasm higher to 130. L-SIL cells show cytoplasm-nucleus values less than 120. The rank between 120–130 in cytoplasm-nucleus subtraction corresponds to evolution between L-SIL and H-SIL. Sensibility and specificity values were 100%, the negative likelihood ratio was zero and Kappa coefficient was equal to 1. Conclusions A new diagnostic methodology of clinic applicability was developed based on fractal and euclidean geometry, which is useful for evaluation of cervix cytology. PMID:24742118

  5. Tsonis final project report

    SciTech Connect

    Duane, Greg; Tsonis, Anastasios; Kocarev, Ljupco; Tribbia, Joseph

    2014-11-20

    This collaborative reserach has several components but the main idea is that when imperfect copies of a given nonlinear dynamical system are coupled, they may synchronize for some set of coupling parameters. This idea is to be tested for several IPCC-like models each one with its own formulation and representing an “imperfect” copy of the true climate system. By computing the coupling parameters, which will lead the models to a synchronized state, a consensus on climate change simulations may be achieved.

  6. Quantum features of natural cellular automata

    NASA Astrophysics Data System (ADS)

    Elze, Hans-Thomas

    2016-03-01

    Cellular automata can show well known features of quantum mechanics, such as a linear rule according to which they evolve and which resembles a discretized version of the Schrödinger equation. This includes corresponding conservation laws. The class of “natural” Hamiltonian cellular automata is based exclusively on integer-valued variables and couplings and their dynamics derives from an Action Principle. They can be mapped reversibly to continuum models by applying Sampling Theory. Thus, “deformed” quantum mechanical models with a finite discreteness scale l are obtained, which for l → 0 reproduce familiar continuum results. We have recently demonstrated that such automata can form “multipartite” systems consistently with the tensor product structures of nonrelativistic many-body quantum mechanics, while interacting and maintaining the linear evolution. Consequently, the Superposition Principle fully applies for such primitive discrete deterministic automata and their composites and can produce the essential quantum effects of interference and entanglement.

  7. Animal and cellular models of Friedreich ataxia.

    PubMed

    Perdomini, Morgane; Hick, Aurore; Puccio, Hélène; Pook, Mark A

    2013-08-01

    The development and use of animal and cellular models of Friedreich ataxia (FRDA) are essential requirements for the understanding of FRDA disease mechanisms and the investigation of potential FRDA therapeutic strategies. Although animal and cellular models of lower organisms have provided valuable information on certain aspects of FRDA disease and therapy, it is intuitive that the most useful models are those of mammals and mammalian cells, which are the closest in physiological terms to FRDA patients. To date, there have been considerable efforts put into the development of several different FRDA mouse models and relevant FRDA mouse and human cell line systems. We summarize the principal mammalian FRDA models, discuss the pros and cons of each system, and describe the ways in which such models have been used to address two of the fundamental, as yet unanswered, questions regarding FRDA. Namely, what is the exact pathophysiology of FRDA and what is the detailed genetic and epigenetic basis of FRDA?

  8. Cellular Structure Pattern in Dielectric Barrier Discharge

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Dong, Lifang; Liu, Weibo; Gao, Xing; Wei, Lingyan

    2015-12-01

    We report the observation of a cellular structure pattern in a dielectric barrier discharge system. The evolution sequence and phase diagram of the pattern are given. It is firstly observed that the "cell nucleus" fire three or even more times at a fixed location at the rising edge of the applied voltage, and that the "cell walls" which have the same discharge times with the "cell nucleus" are ignited slightly after the "cell nucleus". By observing a series of frames recorded by a high speed video camera, it is found that the cellular structure pattern consists of volume discharges (VDs) and surface discharges (SDs) corresponding to the "cell nucleus" and "cell walls" respectively. That VDs and SDs are ignited in turn for several times in each half cycle of the applied voltage confirms the fact that VDs induce the SDs and SDs also affect the following VDs.

  9. The Spatiotemporal Cellular Dynamics of Lung Immunity

    PubMed Central

    Lelkes, E.; Headley, M.B.; Thornton, E.E.; Looney, M.R.; Krummel, M.F.

    2014-01-01

    The lung is a complex structure that is interdigitated with immune cells. Understanding the 4-dimensional process of normal and defective lung function and immunity has been a centuries-old problem. Challenges intrinsic to the lung have limited adequate microscopic evaluation of its cellular dynamics in real time, until recently. Because of emerging technologies, we now recognize alveolar-to-airway transport of inhaled antigen. We understand the nature of neutrophil entry during lung injury and are learning more about cellular interactions during inflammatory states. Insights are also accumulating in lung development and the metatastatic niche of the lung. Here we assess the developing technology of lung imaging, its merits for studies of pathophysiology and areas where further advances are needed. PMID:24974157

  10. Molecular kinesis in cellular function and plasticity.

    PubMed

    Tiedge, H; Bloom, F E; Richter, D

    2001-06-19

    Intracellular transport and localization of cellular components are essential for the functional organization and plasticity of eukaryotic cells. Although the elucidation of protein transport mechanisms has made impressive progress in recent years, intracellular transport of RNA remains less well understood. The National Academy of Sciences Colloquium on Molecular Kinesis in Cellular Function and Plasticity therefore was devised as an interdisciplinary platform for participants to discuss intracellular molecular transport from a variety of different perspectives. Topics covered at the meeting included RNA metabolism and transport, mechanisms of protein synthesis and localization, the formation of complex interactive protein ensembles, and the relevance of such mechanisms for activity-dependent regulation and synaptic plasticity in neurons. It was the overall objective of the colloquium to generate momentum and cohesion for the emerging research field of molecular kinesis.

  11. [Cellular therapy and leg ulcers: Future approaches].

    PubMed

    Senet, P

    2015-01-01

    The prevalence of leg ulcers, which are most commonly caused by venous insufficiency, is high in Europe. Current treatments are fairly unsatisfactory, with long healing times in many cases, as well as a high risk of relapse. Over the last 15 years, improved understanding of the cellular and molecular mechanisms at work in delayed wound healing has contributed to the development of cellular therapy in this field. The use of keratinocytes or cultured fibroblasts, whether autogenic or allogenic, has been of little value in terms of either healing times or rates of complete healing. For the moment, there are very few allogenic skin substitutes available; they are expensive and have been insufficiently studied in the indication of leg ulcers. Pluripotent mesenchymal adult stem cells have proved capable of accelerating wound healing in animal models and their study in chronic wounds in humans is currently awaited.

  12. Laboratory constitutive characterization of cellular concrete.

    SciTech Connect

    Hardy, Robert Douglas; Lee, Moo Yul; Bronowski, David R.

    2004-03-01

    To establish mechanical material properties of cellular concrete mixes, a series of quasi-static, compression and tension tests have been completed. This report summarizes the test methods, set-up, relevant observations, and results from the constitutive experimental efforts. Results from the uniaxial and triaxial compression tests established failure criteria for the cellular concrete in terms of stress invariants I{sub 1} and J{sub 2}. {radical}J{sub 2} (MPa) = 297.2 - 278.7 exp{sup -0.000455 I}{sub 1}{sup (MPa)} for the 90-pcf concrete {radical}J{sub 2} (MPa) = 211.4 - 204.2 exp {sup -0.000628 I}{sub 1}{sup (MPa)} for the 60-pcf concrete

  13. Systematic analysis of endocytosis by cellular perturbations.

    PubMed

    Kühling, Lena; Schelhaas, Mario

    2014-01-01

    Endocytosis is an essential process of eukaryotic cells that facilitates numerous cellular and organismal functions. The formation of vesicles from the plasma membrane serves the internalization of ligands and receptors and leads to their degradation or recycling. A number of distinct mechanisms have been described over the years, several of which are only partially characterized in terms of mechanism and function. These are often referred to as novel endocytic pathways. The pathways differ in their mode of uptake and in their intracellular destination. Here, an overview of the set of cellular proteins that facilitate the different pathways is provided. Further, the approaches to distinguish between the pathways by different modes of perturbation are critically discussed, emphasizing the use of genetic tools such as dominant negative mutant proteins.

  14. A cellular glass substrate solar concentrator

    NASA Technical Reports Server (NTRS)

    Bedard, R.; Bell, D.

    1980-01-01

    The design of a second generation point focusing solar concentration is discussed. The design is based on reflective gores fabricated of thin glass mirror bonded continuously to a contoured substrate of cellular glass. The concentrator aperture and structural stiffness was optimized for minimum concentrator cost given the performance requirement of delivering 56 kWth to a 22 cm diameter receiver aperture with a direct normal insolation of 845 watts sq m and an operating wind of 50 kmph. The reflective panel, support structure, drives, foundation and instrumentation and control subsystem designs, optimized for minimum cost, are summarized. The use of cellular glass as a reflective panel substrate material is shown to offer significant weight and cost advantages compared to existing technology materials.

  15. Cellular senescence and the aging brain

    PubMed Central

    Chinta, Shankar J.; Woods, Georgia; Rane, Anand; Demaria, Marco; Campisi, Judith; Andersen, Julie K

    2014-01-01

    Cellular senescence is a potent anti-cancer mechanism that arrests the proliferation of mitotically competent cells to prevent malignant transformation. Senescent cells accumulate with age in a variety of human and mouse tissues where they express a complex ‘senescence-associated secretory phenotype’ (SASP). The SASP includes many pro-inflammatory cytokines, chemokines, growth factors and proteases that have the potential to cause or exacerbate age-related pathology, both degenerative and hyperplastic. While cellular senescence in peripheral tissues has recently been linked to a number of age-related pathologies, its involvement in brain aging is just beginning to be explored. Recent data generated by several laboratories suggest both aging and age-related neurodegenerative diseases are accompanied by an increase in SASP-expressing senescent cells of non-neuronal origin in the brain. Moreover, this increase correlates with neurodegeneration. Senescent cells in the brain could therefore constitute novel therapeutic targets for treating age-related neuropathologies. PMID:25281806

  16. Total cellular glycomics allows characterizing cells and streamlining the discovery process for cellular biomarkers.

    PubMed

    Fujitani, Naoki; Furukawa, Jun-ichi; Araki, Kayo; Fujioka, Tsuyoshi; Takegawa, Yasuhiro; Piao, Jinhua; Nishioka, Taiki; Tamura, Tomohiro; Nikaido, Toshio; Ito, Makoto; Nakamura, Yukio; Shinohara, Yasuro

    2013-02-05

    Although many of the frequently used pluripotency biomarkers are glycoconjugates, a glycoconjugate-based exploration of novel cellular biomarkers has proven difficult due to technical difficulties. This study reports a unique approach for the systematic overview of all major classes of oligosaccharides in the cellular glycome. The proposed method enabled mass spectrometry-based structurally intensive analyses, both qualitatively and quantitatively, of cellular N- and O-linked glycans derived from glycoproteins, glycosaminoglycans, and glycosphingolipids, as well as free oligosaccharides of human embryonic stem cells (hESCs), induced pluripotent stem cells (hiPSCs), and various human cells derived from normal and carcinoma cells. Cellular total glycomes were found to be highly cell specific, demonstrating their utility as unique cellular descriptors. Structures of glycans of all classes specifically observed in hESCs and hiPSCs tended to be immature in general, suggesting the presence of stem cell-specific glycosylation spectra. The current analysis revealed the high similarity of the total cellular glycome between hESCs and hiPSCs, although it was suggested that hESCs are more homogeneous than hiPSCs from a glycomic standpoint. Notably, this study enabled a priori identification of known pluripotency biomarkers such as SSEA-3, -4, and -5 and Tra-1-60/81, as well as a panel of glycans specifically expressed by hESCs and hiPSCs.

  17. Cellular responses to environmental DNA damage

    SciTech Connect

    Not Available

    1994-08-01

    This volume contains the proceedings of the conference entitled Cellular Responses to Environmental DNA Damage held in Banff,Alberta December 1--6, 1991. The conference addresses various aspects of DNA repair in sessions titled DNA repair; Basic Mechanisms; Lesions; Systems; Inducible Responses; Mutagenesis; Human Population Response Heterogeneity; Intragenomic DNA Repair Heterogeneity; DNA Repair Gene Cloning; Aging; Human Genetic Disease; and Carcinogenesis. Individual papers are represented as abstracts of about one page in length.

  18. GARDENS OF EDEN OF ELEMENTARY CELLULAR AUTOMATA.

    SciTech Connect

    Barrett, C. L.; Chen, W. Y. C.; Reidys, C. M.

    2001-01-01

    Using de Bruijn graphs, we give a characterization of elementary cellular automata on the linear lattice that do not have any Gardens of Eden. It turns out that one can easily recoginze a CA that does not have any Gardens of Eden by looking at its de Bruijn graph. We also present a sufficient condition for the set of words accepted by a CA not to constitute a finite-complement language.

  19. Inferring cellular networks – a review

    PubMed Central

    Markowetz, Florian; Spang, Rainer

    2007-01-01

    In this review we give an overview of computational and statistical methods to reconstruct cellular networks. Although this area of research is vast and fast developing, we show that most currently used methods can be organized by a few key concepts. The first part of the review deals with conditional independence models including Gaussian graphical models and Bayesian networks. The second part discusses probabilistic and graph-based methods for data from experimental interventions and perturbations. PMID:17903286

  20. Gravitational studies in cellular and developmental biology

    NASA Technical Reports Server (NTRS)

    Spooner, B. S.

    1992-01-01

    The paucity of data on the role of gravity in cellular and developmental biology has been examined, and a hypothesis has been generated that unifies potential gravity sensitivity in both plant and animal systems. This hypothesis considers the macromolecular order and functional importance of the extracellular matrix compartment, the intracellular cytoskeleton compartment, and the connecting plasma membrane-signal transduction compartment of plant and animal systems as potentially sensitive to alterations in the unit gravity environment in which they evolved.

  1. High Speed Internet Access Using Cellular Infrastructure

    DTIC Science & Technology

    2004-09-01

    Telecommunications, [http://www.cept.org/], April 2004. Dawkins, S., Montenegro, G ., Kojo, M., and Magret, V., RFC 3150, End to End Performance ...Internet Access Using Cellular Infrastructure 6. AUTHOR(S) Ioannis Chatziioannidis 5. FUNDING NUMBERS 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES...Naval Postgraduate School Monterey, CA 93943-5000 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING /MONITORING AGENCY NAME(S) AND

  2. Cellular Automation of Galactic Habitable Zone

    NASA Astrophysics Data System (ADS)

    Vukotic, B.; Cirkovic, M. M.

    2010-09-01

    We present a preliminary results of our Galactic Habitable Zone (GHZ) 2D probabilistic cellular automata models. The relevant time-scales (emergence of life, it's diversification and evolution influenced with the global risk function) are modeled as the probability matrix elements and are chosen in accordance with the Copernican principle to be well-represented by the data inferred from the Earth's fossil record. With Fermi's paradox as a main boundary condition the resulting histories of astrobiological landscape are discussed.

  3. Cellular automaton formulation of passive scalar dynamics

    NASA Technical Reports Server (NTRS)

    Chen, Hudong; Matthaeus, William H.

    1987-01-01

    Cellular automata modeling of the advection of a passive scalar in a two-dimensional flow is examined in the context of discrete lattice kinetic theory. It is shown that if the passive scalar is represented by tagging or 'coloring' automation particles a passive advection-diffusion equation emerges without use of perturbation expansions. For the specific case of the hydrodynamic lattice gas model of Frisch et al. (1986), the diffusion coefficient is calculated by perturbation.

  4. New cellular automaton model for magnetohydrodynamics

    NASA Technical Reports Server (NTRS)

    Chen, Hudong; Matthaeus, William H.

    1987-01-01

    A new type of two-dimensional cellular automation method is introduced for computation of magnetohydrodynamic fluid systems. Particle population is described by a 36-component tensor referred to a hexagonal lattice. By appropriate choice of the coefficients that control the modified streaming algorithm and the definition of the macroscopic fields, it is possible to compute both Lorentz-force and magnetic-induction effects. The method is local in the microscopic space and therefore suited to massively parallel computations.

  5. Cellular automata in photonic cavity arrays.

    PubMed

    Li, Jing; Liew, T C H

    2016-10-31

    We propose theoretically a photonic Turing machine based on cellular automata in arrays of nonlinear cavities coupled with artificial gauge fields. The state of the system is recorded making use of the bistability of driven cavities, in which losses are fully compensated by an external continuous drive. The sequential update of the automaton layers is achieved automatically, by the local switching of bistable states, without requiring any additional synchronization or temporal control.

  6. Important cellular targets for antimicrobial photodynamic therapy.

    PubMed

    Awad, Mariam M; Tovmasyan, Artak; Craik, James D; Batinic-Haberle, Ines; Benov, Ludmil T

    2016-09-01

    The persistent problem of antibiotic resistance has created a strong demand for new methods for therapy and disinfection. Photodynamic inactivation (PDI) of microbes has demonstrated promising results for eradication of antibiotic-resistant strains. PDI is based on the use of a photosensitive compound (photosensitizer, PS), which upon illumination with visible light generates reactive species capable of damaging and killing microorganisms. Since photogenerated reactive species are short lived, damage is limited to close proximity of the PS. It is reasonable to expect that the larger the number of damaged targets is and the greater their variety is, the higher the efficiency of PDI is and the lower the chances for development of resistance are. Exact molecular mechanisms and specific targets whose damage is essential for microbial inactivation have not been unequivocally established. Two main cellular components, DNA and plasma membrane, are regarded as the most important PDI targets. Using Zn porphyrin-based PSs and Escherichia coli as a model Gram-negative microorganism, we demonstrate that efficient photoinactivation of bacteria can be achieved without detectable DNA modification. Among the cellular components which are modified early during illumination and constitute key PDI targets are cytosolic enzymes, membrane-bound protein complexes, and the plasma membrane. As a result, membrane barrier function is lost, and energy and reducing equivalent production is disrupted, which in turn compromises cell defense mechanisms, thus augmenting the photoinduced oxidative injury. In conclusion, high PDI antimicrobial effectiveness does not necessarily require impairment of a specific critical cellular component and can be achieved by inducing damage to multiple cellular targets.

  7. Parasitoid wasp venom SERCA regulates Drosophila calcium levels and inhibits cellular immunity.

    PubMed

    Mortimer, Nathan T; Goecks, Jeremy; Kacsoh, Balint Z; Mobley, James A; Bowersock, Gregory J; Taylor, James; Schlenke, Todd A

    2013-06-04

    Because parasite virulence factors target host immune responses, identification and functional characterization of these factors can provide insight into poorly understood host immune mechanisms. The fruit fly Drosophila melanogaster is a model system for understanding humoral innate immunity, but Drosophila cellular innate immune responses remain incompletely characterized. Fruit flies are regularly infected by parasitoid wasps in nature and, following infection, flies mount a cellular immune response culminating in the cellular encapsulation of the wasp egg. The mechanistic basis of this response is largely unknown, but wasps use a mixture of virulence proteins derived from the venom gland to suppress cellular encapsulation. To gain insight into the mechanisms underlying wasp virulence and fly cellular immunity, we used a joint transcriptomic/proteomic approach to identify venom genes from Ganaspis sp.1 (G1), a previously uncharacterized Drosophila parasitoid species, and found that G1 venom contains a highly abundant sarco/endoplasmic reticulum calcium ATPase (SERCA) pump. Accordingly, we found that fly immune cells termed plasmatocytes normally undergo a cytoplasmic calcium burst following infection, and that this calcium burst is required for activation of the cellular immune response. We further found that the plasmatocyte calcium burst is suppressed by G1 venom in a SERCA-dependent manner, leading to the failure of plasmatocytes to become activated and migrate toward G1 eggs. Finally, by genetically manipulating plasmatocyte calcium levels, we were able to alter fly immune success against G1 and other parasitoid species. Our characterization of parasitoid wasp venom proteins led us to identify plasmatocyte cytoplasmic calcium bursts as an important aspect of fly cellular immunity.

  8. Cytoskeletal Mechanisms for Breaking Cellular Symmetry

    PubMed Central

    Mullins, R. Dyche

    2010-01-01

    Cytoskeletal systems are networks of polymers found in all eukaryotic and many prokaryotic cells. Their purpose is to transmit and integrate information across cellular dimensions and help turn a disorderly mob of macromolecules into a spatially organized, living cell. Information, in this context, includes physical and chemical properties relevant to cellular physiology, including: the number and activity of macromolecules, cell shape, and mechanical force. Most animal cells are 10–50 microns in diameter, whereas the macromolecules that comprise them are 10,000-fold smaller (2–20 nm). To establish long-range order over cellular length scales, individual molecules must, therefore, self-assemble into larger polymers, with lengths (0.1–20 m) comparable to the size of a cell. These polymers must then be cross-linked into organized networks that fill the cytoplasm. Such cell-spanning polymer networks enable different parts of the cytoplasm to communicate directly with each other, either by transmitting forces or by carrying cargo from one spot to another. PMID:20182610

  9. Ceramide glycosylation potentiates cellular multidrug resistance.

    PubMed

    Liu, Y Y; Han, T Y; Giuliano, A E; Cabot, M C

    2001-03-01

    Ceramide glycosylation, through glucosylceramide synthase (GCS), allows cellular escape from ceramide-induced programmed cell death. This glycosylation event confers cancer cell resistance to cytotoxic anticancer agents [Liu, Y. Y., Han, T. Y., Giuliano, A. E., and M. C. Cabot. (1999) J. Biol. Chem. 274, 1140-1146]. We previously found that glucosylceramide, the glycosylated form of ceramide, accumulates in adriamycin-resistant breast carcinoma cells, in vinblastine-resistant epithelioid carcinoma cells, and in tumor specimens from patients showing poor response to chemotherapy. Here we show that multidrug resistance can be increased over baseline and then totally reversed in human breast cancer cells by GCS gene targeting. In adriamycin-resistant MCF-7-AdrR cells, transfection of GCS upgraded multidrug resistance, whereas transfection of GCS antisense markedly restored cellular sensitivity to anthracyclines, Vinca alkaloids, taxanes, and other anticancer drugs. Sensitivity to the various drugs by GCS antisense transfection increased 7- to 240-fold and was consistent with the resumption of ceramide-caspase-apoptotic signaling. GCS targeting had little influence on cellular sensitivity to either 5-FU or cisplatin, nor did it modify P-glycoprotein expression or rhodamine-123 efflux. GCS antisense transfection did enhance rhodamine-123 uptake compared with parent MCF-7-AdrR cells. This study reveals that GCS is a novel mechanism of multidrug resistance and positions GCS antisense as an innovative force to overcome multidrug resistance in cancer chemotherapy.

  10. HDACi: cellular effects, opportunities for restorative dentistry.

    PubMed

    Duncan, H F; Smith, A J; Fleming, G J P; Cooper, P R

    2011-12-01

    Acetylation of histone and non-histone proteins alters gene expression and induces a host of cellular effects. The acetylation process is homeostatically balanced by two groups of cellular enzymes, histone acetyltransferases (HATs) and histone deacetylases (HDACs). HAT activity relaxes the structure of the human chromatin, rendering it transcriptionally active, thereby increasing gene expression. In contrast, HDAC activity leads to gene silencing. The enzymatic balance can be 'tipped' by histone deacetylase inhibitors (HDACi), leading to an accumulation of acetylated proteins, which subsequently modify cellular processes including stem cell differentiation, cell cycle, apoptosis, gene expression, and angiogenesis. There is a variety of natural and synthetic HDACi available, and their pleiotropic effects have contributed to diverse clinical applications, not only in cancer but also in non-cancer areas, such as chronic inflammatory disease, bone engineering, and neurodegenerative disease. Indeed, it appears that HDACi-modulated effects may differ between 'normal' and transformed cells, particularly with regard to reactive oxygen species accumulation, apoptosis, proliferation, and cell cycle arrest. The potential beneficial effects of HDACi for health, resulting from their ability to regulate global gene expression by epigenetic modification of DNA-associated proteins, also offer potential for application within restorative dentistry, where they may promote dental tissue regeneration following pulpal damage.

  11. [Cellular and molecular mechanisms of memory].

    PubMed

    Laroche, Serge

    2010-01-01

    A defining characteristic of the brain is its remarkable capacity to undergo activity-dependent functional and morphological remodelling via mechanisms of plasticity that form the basis of our capacity to encode and retain memories. Today, it is generally accepted that one key neurobiological mechanism underlying the formation of memories reside in activity-driven modifications of synaptic strength and structural remodelling of neural networks activated during learning. The discovery and detailed report of the phenomenon generally known as long-term potentiation, a long-lasting activity-dependent form of synaptic strengthening, opened a new chapter in the study of the neurobiological substrate of memory in the vertebrate brain, and this form of synaptic plasticity has now become the dominant model in the search for the cellular bases of learning and memory. To date, the key events in the cellular and molecular mechanisms underlying synaptic plasticity and memory formation are starting to be identified. They require the activation of specific receptors and of several molecular cascades to convert extracellular signals into persistent functional changes in neuronal connectivity. Accumulating evidence suggests that the rapid activation of neuronal gene programs is a key mechanism underlying the enduring modification of neural networks required for the laying down of memory. The recent developments in the search for the cellular and molecular mechanisms of memory storage are reviewed.

  12. [Cellular and molecular mechanisms of memory].

    PubMed

    Laroche, S

    2001-01-01

    There has been nearly a century of interest in the idea that information is encoded in the brain as specific spatio-temporal patterns of activity in distributed networks and stored as changes in the efficacy of synaptic connections on neurons that are activated during learning. The discovery and detailed report of the phenomenon generally known as long-term potentiation opened a new chapter in the study of synaptic plasticity in the vertebrate brain, and this form of synaptic plasticity has now become the dominant model in the search for the cellular bases of learning and memory. To date, the key events in the cellular and molecular mechanisms underlying synaptic plasticity are starting to be identified. They require the activation of specific receptors and of several molecular cascades to convert extracellular signals into persistent functional changes in neuronal connectivity. Accumulating evidence suggests that the rapid activation of the genetic machinery is a key mechanism underlying the enduring modification of neural networks required for the laying down of memory. The recent developments in the search for the cellular and molecular mechanisms of memory storage are reviewed.

  13. Influence of electric field on cellular migration

    NASA Astrophysics Data System (ADS)

    Guido, Isabella; Bodenschatz, Eberhard

    Cells have the ability to detect continuous current electric fields (EFs) and respond to them with a directed migratory movement. Dictyostelium discoideum (D.d.) cells, a key model organism for the study of eukaryotic chemotaxis, orient and migrate toward the cathode under the influence of an EF. The underlying sensing mechanism and whether it is shared by the chemotactic response pathway remains unknown. Whereas genes and proteins that mediate the electric sensing as well as that define the migration direction have been previously investigated in D.d. cells, a deeper knowledge about the cellular kinematic effects caused by the EF is still lacking. Here we show that besides triggering a directional bias the electric field influences the cellular kinematics by accelerating the movement of cells along their path. We found that the migratory velocity of the cells in an EF increases linearly with the exposure time. Through the analysis of the PI3K and Phg2 distribution in the cytosol and of the cellular adherence to the substrate we aim at elucidating whereas this speed up effect in the electric field is due to either a molecular signalling or the interaction with the substrate. This work is part of the MaxSynBio Consortium which is jointly funded by the Federal Ministry of Education and Research of Germany and the Max Planck Society.

  14. Literature Review on Dynamic Cellular Manufacturing System

    NASA Astrophysics Data System (ADS)

    Nouri Houshyar, A.; Leman, Z.; Pakzad Moghadam, H.; Ariffin, M. K. A. M.; Ismail, N.; Iranmanesh, H.

    2014-06-01

    In previous decades, manufacturers faced a lot of challenges because of globalization and high competition in markets. These problems arise from shortening product life cycle, rapid variation in demand of products, and also rapid changes in manufcaturing technologies. Nowadays most manufacturing companies expend considerable attention for improving flexibility and responsiveness in order to overcome these kinds of problems and also meet customer's needs. By considering the trend toward the shorter product life cycle, the manufacturing environment is towards manufacturing a wide variety of parts in small batches [1]. One of the major techniques which are applied for improving manufacturing competitiveness is Cellular Manufacturing System (CMS). CMS is type of manufacturing system which tries to combine flexibility of job shop and also productivity of flow shop. In addition, Dynamic cellular manufacturing system which considers different time periods for the manufacturing system becomes an important topic and attracts a lot of attention to itself. Therefore, this paper made attempt to have a brief review on this issue and focused on all published paper on this subject. Although, this topic gains a lot of attention to itself during these years, none of previous researchers focused on reviewing the literature of that which can be helpful and useful for other researchers who intend to do the research on this topic. Therefore, this paper is the first study which has focused and reviewed the literature of dynamic cellular manufacturing system.

  15. Cellular arsenic transport pathways in mammals.

    PubMed

    Roggenbeck, Barbara A; Banerjee, Mayukh; Leslie, Elaine M

    2016-11-01

    Natural contamination of drinking water with arsenic results in the exposure of millions of people world-wide to unacceptable levels of this metalloid. This is a serious global health problem because arsenic is a Group 1 (proven) human carcinogen and chronic exposure is known to cause skin, lung, and bladder tumors. Furthermore, arsenic exposure can result in a myriad of other adverse health effects including diseases of the cardiovascular, respiratory, neurological, reproductive, and endocrine systems. In addition to chronic environmental exposure to arsenic, arsenic trioxide is approved for the clinical treatment of acute promyelocytic leukemia, and is in clinical trials for other hematological malignancies as well as solid tumors. Considerable inter-individual variability in susceptibility to arsenic-induced disease and toxicity exists, and the reasons for such differences are incompletely understood. Transport pathways that influence the cellular uptake and export of arsenic contribute to regulating its cellular, tissue, and ultimately body levels. In the current review, membrane proteins (including phosphate transporters, aquaglyceroporin channels, solute carrier proteins, and ATP-binding cassette transporters) shown experimentally to contribute to the passage of inorganic, methylated, and/or glutathionylated arsenic species across cellular membranes are discussed. Furthermore, what is known about arsenic transporters in organs involved in absorption, distribution, and metabolism and how transport pathways contribute to arsenic elimination are described.

  16. Targeting cellular metabolism to improve cancer therapeutics.

    PubMed

    Zhao, Y; Butler, E B; Tan, M

    2013-03-07

    The metabolic properties of cancer cells diverge significantly from those of normal cells. Energy production in cancer cells is abnormally dependent on aerobic glycolysis. In addition to the dependency on glycolysis, cancer cells have other atypical metabolic characteristics such as increased fatty acid synthesis and increased rates of glutamine metabolism. Emerging evidence shows that many features characteristic to cancer cells, such as dysregulated Warburg-like glucose metabolism, fatty acid synthesis and glutaminolysis are linked to therapeutic resistance in cancer treatment. Therefore, targeting cellular metabolism may improve the response to cancer therapeutics and the combination of chemotherapeutic drugs with cellular metabolism inhibitors may represent a promising strategy to overcome drug resistance in cancer therapy. Recently, several review articles have summarized the anticancer targets in the metabolic pathways and metabolic inhibitor-induced cell death pathways, however, the dysregulated metabolism in therapeutic resistance, which is a highly clinical relevant area in cancer metabolism research, has not been specifically addressed. From this unique angle, this review article will discuss the relationship between dysregulated cellular metabolism and cancer drug resistance and how targeting of metabolic enzymes, such as glucose transporters, hexokinase, pyruvate kinase M2, lactate dehydrogenase A, pyruvate dehydrogenase kinase, fatty acid synthase and glutaminase can enhance the efficacy of common therapeutic agents or overcome resistance to chemotherapy or radiotherapy.

  17. Transcriptome transfer produces a predictable cellular phenotype

    PubMed Central

    Sul, Jai-Yoon; Wu, Chia-wen K.; Zeng, Fanyi; Jochems, Jeanine; Lee, Miler T.; Kim, Tae Kyung; Peritz, Tiina; Buckley, Peter; Cappelleri, David J.; Maronski, Margaret; Kim, Minsun; Kumar, Vijay; Meaney, David; Kim, Junhyong; Eberwine, James

    2009-01-01

    Cellular phenotype is the conglomerate of multiple cellular processes involving gene and protein expression that result in the elaboration of a cell's particular morphology and function. It has been thought that differentiated postmitotic cells have their genomes hard wired, with little ability for phenotypic plasticity. Here we show that transfer of the transcriptome from differentiated rat astrocytes into a nondividing differentiated rat neuron resulted in the conversion of the neuron into a functional astrocyte-like cell in a time-dependent manner. This single-cell study permits high resolution of molecular and functional components that underlie phenotype identity. The RNA population from astrocytes contains RNAs in the appropriate relative abundances that give rise to regulatory RNAs and translated proteins that enable astrocyte identity. When transferred into the postmitotic neuron, the astrocyte RNA population converts 44% of the neuronal host cells into the destination astrocyte-like phenotype. In support of this observation, quantitative measures of cellular morphology, single-cell PCR, single-cell microarray, and single-cell functional analyses have been performed. The host-cell phenotypic changes develop over many weeks and are persistent. We call this process of RNA-induced phenotype changes, transcriptome-induced phenotype remodeling. PMID:19380745

  18. Pirin Inhibits Cellular Senescence in Melanocytic Cells

    PubMed Central

    Licciulli, Silvia; Luise, Chiara; Scafetta, Gaia; Capra, Maria; Giardina, Giuseppina; Nuciforo, Paolo; Bosari, Silvano; Viale, Giuseppe; Mazzarol, Giovanni; Tonelli, Chiara; Lanfrancone, Luisa; Alcalay, Myriam

    2011-01-01

    Cellular senescence has been widely recognized as a tumor suppressing mechanism that acts as a barrier to cancer development after oncogenic stimuli. A prominent in vivo model of the senescence barrier is represented by nevi, which are composed of melanocytes that, after an initial phase of proliferation induced by activated oncogenes (most commonly BRAF), are blocked in a state of cellular senescence. Transformation to melanoma occurs when genes involved in controlling senescence are mutated or silenced and cells reacquire the capacity to proliferate. Pirin (PIR) is a highly conserved nuclear protein that likely functions as a transcriptional regulator whose expression levels are altered in different types of tumors. We analyzed the expression pattern of PIR in adult human tissues and found that it is expressed in melanocytes and has a complex pattern of regulation in nevi and melanoma: it is rarely detected in mature nevi, but is expressed at high levels in a subset of melanomas. Loss of function and overexpression experiments in normal and transformed melanocytic cells revealed that PIR is involved in the negative control of cellular senescence and that its expression is necessary to overcome the senescence barrier. Our results suggest that PIR may have a relevant role in melanoma progression. PMID:21514450

  19. Cellular and Molecular Basis of Liver Development

    PubMed Central

    Shin, Donghun; Singh Monga, Satdarshan Pal

    2015-01-01

    Liver is a prime organ responsible for synthesis, metabolism, and detoxification. The organ is endodermal in origin and its development is regulated by temporal, complex, and finely balanced cellular and molecular interactions that dictate its origin, growth, and maturation. We discuss the relevance of endoderm patterning, which truly is the first step toward mapping of domains that will give rise to specific organs. Once foregut patterning is completed, certain cells within the foregut endoderm gain competence in the form of expression of certain transcription factors that allow them to respond to certain inductive signals. Hepatic specification is then a result of such inductive signals, which often emanate from the surrounding mesenchyme. During hepatic specification bipotential hepatic stem cells or hepatoblasts become apparent and undergo expansion, which results in a visible liver primordium during the stage of hepatic morphogenesis. Hepatoblasts next differentiate into either hepatocytes or cholangiocytes. The expansion and differentiation is regulated by cellular and molecular interactions between hepatoblasts and mesenchymal cells including sinusoidal endothelial cells, stellate cells, and also innate hematopoietic elements. Further maturation of hepatocytes and cholangiocytes continues during late hepatic development as a function of various growth factors. At this time, liver gains architectural novelty in the form of zonality and at cellular level acquires polarity. A comprehensive elucidation of such finely tuned developmental cues have been the basis of transdifferentiation of various types of stem cells to hepatocyte-like cells for purposes of understanding health and disease and for therapeutic applications. PMID:23720330

  20. A Real Space Cellular Automaton Laboratory

    NASA Astrophysics Data System (ADS)

    Rozier, O.; Narteau, C.

    2013-12-01

    Investigations in geomorphology may benefit from computer modelling approaches that rely entirely on self-organization principles. In the vast majority of numerical models, instead, points in space are characterised by a variety of physical variables (e.g. sediment transport rate, velocity, temperature) recalculated over time according to some predetermined set of laws. However, there is not always a satisfactory theoretical framework from which we can quantify the overall dynamics of the system. For these reasons, we prefer to concentrate on interaction patterns using a basic cellular automaton modelling framework, the Real Space Cellular Automaton Laboratory (ReSCAL), a powerful and versatile generator of 3D stochastic models. The objective of this software suite released under a GNU license is to develop interdisciplinary research collaboration to investigate the dynamics of complex systems. The models in ReSCAL are essentially constructed from a small number of discrete states distributed on a cellular grid. An elementary cell is a real-space representation of the physical environment and pairs of nearest neighbour cells are called doublets. Each individual physical process is associated with a set of doublet transitions and characteristic transition rates. Using a modular approach, we can simulate and combine a wide range of physical, chemical and/or anthropological processes. Here, we present different ingredients of ReSCAL leading to applications in geomorphology: dune morphodynamics and landscape evolution. We also discuss how ReSCAL can be applied and developed across many disciplines in natural and human sciences.

  1. Exponential stability of delayed and impulsive cellular neural networks with partially Lipschitz continuous activation functions.

    PubMed

    Song, Xueli; Xin, Xing; Huang, Wenpo

    2012-05-01

    The paper discusses exponential stability of distributed delayed and impulsive cellular neural networks with partially Lipschitz continuous activation functions. By relative nonlinear measure method, some novel criteria are obtained for the uniqueness and exponential stability of the equilibrium point. Our method abandons usual assumptions on global Lipschitz continuity, boundedness and monotonicity of activation functions. Our results are generalization and improvement of some existing ones. Finally, two examples and their simulations are presented to illustrate the correctness of our analysis.

  2. Role of Cellular Components of Mosquito Cells in Viral Replication and Transmission.

    DTIC Science & Technology

    1981-03-17

    replicating in mosquito cells, experiments similar to those described above were conducted employing Eastern equine encephalitis virus ( alphavirus ...7 D-R126 612 ROLE OF CELLULAR COMPONENTS OF MOSQUITO CELLS IN VIRAL 1/1 REPLICATION AND TRANSMISSION(U) INDIANA UNIV AT INDIANAPOLIS SCHOOL OF...MOSQUITO CELLS IN VIRAL REPLICATION AND TRANSMISSION Annual Report Final Report Robert H. Schloemer March 17, 1981 Supported by U.S. Army Medical

  3. MSSM without free parameters

    NASA Astrophysics Data System (ADS)

    Kitano, Ryuichiro; Motono, Ryuji; Nagai, Minoru

    2016-12-01

    It is often argued that the minimal supersymmetric standard model has O (100 ) free parameters, and the generic parameter region is already excluded by the null observation of the flavor and C P -violating processes as well as the constraints from the LHC experiments. This situation naturally leads us to consider the case where all the dangerous soft supersymmetry breaking terms, such as the scalar masses and scalar couplings, are absent, while only the unified gaugino mass term and the μ term are nonvanishing at the grand unification scale. We revisit this simple situation taking into account the observed Higgs boson mass, 125 GeV. Since the gaugino mass and the μ term are fixed in order to explain the Higgs boson and the Z boson masses, there is no free parameter left in this scenario. We find that there are three independent parameter sets that exist including ones which have not been discussed in the literature. We also find that the abundance of the dark matter can be explained by relic gravitinos which are nonthermally produced as decay products of the supersymmetry particles while satisfying constraints from big bang nucleosynthesis. We discuss the effects of the gravity mediation which generically gives a contribution to the soft terms of the order of the gravitino mass. It turns out that a newly found parameter set is preferable to explain the Higgs boson mass as well as the gravitino dark matter while satisfying the constraints from the electric dipole moments of the electron and the nucleon.

  4. Final Technical Report

    SciTech Connect

    Maxwell, Mike, J., P.E.

    2012-08-30

    The STI product is the Final Technical Report from ReliOn, Inc. for contract award DE-EE0000487: Recovery Act PEM Fuel Cell Systems Providing Emergency Reserve and Backup Power. The program covered the turnkey deployment of 431 ReliOn fuel cell systems at 189 individual sites for AT&T and PG&E with ReliOn functioning as the primary equipment supplier and the project manager. The Final Technical Report provides an executive level summary, a comparison of the actual accomplishments vs. the goals and objectives of the project, as well as a summary of the project activity from the contract award date of August 1, 2009 through the contract expiration date of December 31, 2011. Two photos are included in the body of the report which show hydrogen storage and bulk hydrogen refueling technologies developed as a result of this program.

  5. Cellular membrane trafficking of mesoporous silica nanoparticles

    SciTech Connect

    Fang, I-Ju

    2012-01-01

    This dissertation mainly focuses on the investigation of the cellular membrane trafficking of mesoporous silica nanoparticles. We are interested in the study of endocytosis and exocytosis behaviors of mesoporous silica nanoparticles with desired surface functionality. The relationship between mesoporous silica nanoparticles and membrane trafficking of cells, either cancerous cells or normal cells was examined. Since mesoporous silica nanoparticles were applied in many drug delivery cases, the endocytotic efficiency of mesoporous silica nanoparticles needs to be investigated in more details in order to design the cellular drug delivery system in the controlled way. It is well known that cells can engulf some molecules outside of the cells through a receptor-ligand associated endocytosis. We are interested to determine if those biomolecules binding to cell surface receptors can be utilized on mesoporous silica nanoparticle materials to improve the uptake efficiency or govern the mechanism of endocytosis of mesoporous silica nanoparticles. Arginine-glycine-aspartate (RGD) is a small peptide recognized by cell integrin receptors and it was reported that avidin internalization was highly promoted by tumor lectin. Both RGD and avidin were linked to the surface of mesoporous silica nanoparticle materials to investigate the effect of receptor-associated biomolecule on cellular endocytosis efficiency. The effect of ligand types, ligand conformation and ligand density were discussed in Chapter 2 and 3. Furthermore, the exocytosis of mesoporous silica nanoparticles is very attractive for biological applications. The cellular protein sequestration study of mesoporous silica nanoparticles was examined for further information of the intracellular pathway of endocytosed mesoporous silica nanoparticle materials. The surface functionality of mesoporous silica nanoparticle materials demonstrated selectivity among the materials and cancer and normal cell lines. We aimed to determine

  6. [Division of regulatory cellular systems (Lvov)].

    PubMed

    Kusen', S I

    1995-01-01

    Two departments of the A. V. Palladin Institute of Biochemistry of the National Academy of Sciences of Ukraine were founded in 1969 in Lviv. These were: the Department of Biochemistry of Cell Differentiation headed by Professor S. I. Kusen and Department of Regulation of Cellular Synthesis of Low Molecular Weight Compounds headed by Professor G. M. Shavlovsky. The Lviv Division of the A. V. Palladin Institute of Biochemistry of the National Academy of Sciences of Ukraine with Professor S. I. Kusen as its chief, was founded in 1974 on the basis of these departments and the Laboratory of Modelling of Regulatory Cellular Systems headed by Professor M. P. Derkach. The above mentioned laboratory which was not the structural unit obtained the status of Structural Laboratory of Cellular Biophysics in 1982 and was headed by O. A. Goida, Candidate of biological sciences. From 1983 the Laboratory of Correcting Therapy of Malignant Tumors and Hemoblastoses at the Institute of Molecular Biology and Genetics, Academy of Sciences of Ukraine (Chief--S. V. Ivasivka, Candidate of medical sciences) was included in the structure of the Division. That Laboratory was soon transformed into the Department of Carbohydrate Metabolism Regulation headed by Professor I. D. Holovatsky. In 1988 this Department was renamed into the Department of Glycoprotein Biochemistry and headed by M. D. Lutsik, Doctor of biological sciences. In 1982 one more Laboratory of Biochemical Genetics was founded at the Department of Regulation of Cellular Synthesis of Low Molecular Weight Compounds, in 1988 it was transformed into the Department of Biochemical Genetics (Chief--Professor A. A. Sibirny). In 1989 the Laboratory of Anion Transport was taken from A. V. Palladin Institute of Biochemistry, Academy of Sciences of Ukraine to Lviv Division of this Institute. This laboratory was headed by Professor M. M. Veliky. One more reorganization in the Division structure took place in 1994. The Department of

  7. STS-73 (USML-2) Final Report

    NASA Technical Reports Server (NTRS)

    Rice, James E.

    1996-01-01

    The report is organized into sections representing the phases of work performed in analyzing the STS-73 (USML-2) results. Section 1 briefly outlines the Orbital Acceleration Research Experiment (OARE), system features, coordinates, and measurement parameters. Section 2 describes the results from STS-73. The mission description, data calibration, and representative data obtained on STS-73 are presented. Also, the anomalous performance of OARE on STS-73 is discussed. Finally, Section 3 presents a discussion of accuracy achieved and achievable with OARE.

  8. Overview of molecular, cellular, and genetic neurotoxicology.

    PubMed

    Wallace, David R

    2005-05-01

    It has become increasingly evident that the field of neurotoxicology is not only rapidly growing but also rapidly evolving, especially over the last 20 years. As the number of drugs and environmental and bacterial/viral agents with potential neurotoxic properties has grown, the need for additional testing has increased. Only recently has the technology advanced to a level that neurotoxicologic studies can be performed without operating in a "black box." Examination of the effects of agents that are suspected of being toxic can occur on the molecular (protein-protein), cellular (biomarkers, neuronal function), and genetic (polymorphisms) level. Together, these areas help to elucidate the potential toxic profiles of unknown (and in some cases, known) agents. The area of proteomics is one of the fastest growing areas in science and particularly applicable to neurotoxicology. Lubec et al, provide a review of the potential and limitations of proteomics. Proteomics focuses on a more comprehensive view of cellular proteins and provides considerably more information about the effects of toxins on the CNS. Proteomics can be classified into three different focuses: post-translational modification, protein-expression profiling, and protein-network mapping. Together, these methods represent a more complete and powerful image of protein modifications following potential toxin exposure. Cellular neurotoxicology involves many cellular processes including alterations in cellular energy homeostasis, ion homeostasis, intracellular signaling function, and neurotransmitter release, uptake, and storage. The greatest hurdle in cellular neurotoxicology has been the discovery of appropriate biomarkers that are reliable, reproducible, and easy to obtain. There are biomarkers of exposure effect, and susceptibility. Finding the appropriate biomarker for a particular toxin is a daunting task. The appropriate biomarker for a particular toxin is a daunting task. The advantage to biomarker

  9. Distinguishing between biochemical and cellular function: Are there peptide signatures for cellular function of proteins?

    PubMed

    Jain, Shruti; Bhattacharyya, Kausik; Bakshi, Rachit; Narang, Ankita; Brahmachari, Vani

    2017-04-01

    The genome annotation and identification of gene function depends on conserved biochemical activity. However, in the cell, proteins with the same biochemical function can participate in different cellular pathways and cannot complement one another. Similarly, two proteins of very different biochemical functions are put in the same class of cellular function; for example, the classification of a gene as an oncogene or a tumour suppressor gene is not related to its biochemical function, but is related to its cellular function. We have taken an approach to identify peptide signatures for cellular function in proteins with known biochemical function. ATPases as a test case, we classified ATPases (2360 proteins) and kinases (517 proteins) from the human genome into different cellular function categories such as transcriptional, replicative, and chromatin remodelling proteins. Using publicly available tool, MEME, we identify peptide signatures shared among the members of a given category but not between cellular functional categories; for example, no motif sharing is seen between chromatin remodelling and transporter ATPases, similarly between receptor Serine/Threonine Kinase and Receptor Tyrosine Kinase. There are motifs shared within each category with significant E value and high occurrence. This concept of signature for cellular function was applied to developmental regulators, the polycomb and trithorax proteins which led to the prediction of the role of INO80, a chromatin remodelling protein, in development. This has been experimentally validated earlier for its role in homeotic gene regulation and its interaction with regulatory complexes like the Polycomb and Trithorax complex. Proteins 2017; 85:682-693. © 2016 Wiley Periodicals, Inc.

  10. Modeling and Simulation of the Impact Response of Maraging Steel Linear Cellular Alloys for Structural Energetic Material Applications

    NASA Astrophysics Data System (ADS)

    Jakus, Adam; Fredenburg, Anthony; McCoy, Tammy; Cochran, Joe; Thadhani, Naresh

    2009-06-01

    A refined Johnson-Cook material strength model is developed for predicting the dynamic strain and fracture response of Maraging 250 steel at high-strain rates. Finite element simulations of rod-on-anvil impacts are carried out at velocities exceeding 100m/s and compared with experimental impact tests performed on a 7.62mm gas gun. The transient and final dimensions of the simulated and experimentally impacted rods are compared and Johnson-Cook strength parameters are modified accordingly. The newly developed Maraging 250 steel Johnson-cook strength model is then applied to simulate the impact response of multiple, 25% dense linear cellular alloys (LCA) of various geometries at velocities exceeding 100m/s. Analyses of the deformation, fragmentation, and stress transfer behavior of the simulated LCAs are performed and validated through comparison of corresponding impact experiments performed on the LCAs produced via an extrusion and reduction process. Stress transfer to the interior walls varies as a function of LCA geometry, which also influences the outward fragmentation and energy retention at the cross-section of impact.

  11. An improved Cellular Automata model to simulate the behavior of high density crowd and validation by experimental data

    NASA Astrophysics Data System (ADS)

    Feliciani, Claudio; Nishinari, Katsuhiro

    2016-06-01

    In this article we present an improved version of the Cellular Automata floor field model making use of a sub-mesh system to increase the maximum density allowed during simulation and reproduce phenomena observed in dense crowds. In order to calibrate the model's parameters and to validate it we used data obtained from an empirical observation of bidirectional pedestrian flow. A good agreement was found between numerical simulation and experimental data and, in particular, the double outflow peak observed during the formation of deadlocks could be reproduced in numerical simulations, thus allowing the analysis of deadlock formation and dissolution. Finally, we used the developed high density model to compute the flow-ratio dependent fundamental diagram of bidirectional flow, demonstrating the instability of balanced flow and predicting the bidirectional flow behavior at very high densities. The model we presented here can be used to prevent dense crowd accidents in the future and to investigate the dynamics of the accidents which already occurred in the past. Additionally, fields such as granular and active matter physics may benefit from the developed framework to study different collective phenomena.

  12. Dynamics of the Multiplicity of Cellular Infection in a Plant Virus

    PubMed Central

    Gutiérrez, Serafín; Monsion, Baptiste; Michalakis, Yannis; Blanc, Stéphane

    2010-01-01

    Recombination, complementation and competition profoundly influence virus evolution and epidemiology. Since viruses are intracellular parasites, the basic parameter determining the potential for such interactions is the multiplicity of cellular infection (cellular MOI), i.e. the number of viral genome units that effectively infect a cell. The cellular MOI values that prevail in host organisms have rarely been investigated, and whether they remain constant or change widely during host invasion is totally unknown. Here, we fill this experimental gap by presenting the first detailed analysis of the dynamics of the cellular MOI during colonization of a host plant by a virus. Our results reveal ample variations between different leaf levels during the course of infection, with values starting close to 2 and increasing up to 13 before decreasing to initial levels in the latest infection stages. By revealing wide dynamic changes throughout a single infection, we here illustrate the existence of complex scenarios where the opportunity for recombination, complementation and competition among viral genomes changes greatly at different infection phases and at different locations within a multi-cellular host. PMID:20862320

  13. Regulation of cellular manganese and manganese transport rates in the unicellular alga Chlamydomonas

    SciTech Connect

    Sunda, W.G.; Huntsman, S.A.

    1985-01-01

    The cellular accumulation and uptake kinetics of manganese by Chlamydomonas sp. were studied in model chelate buffer systems. Cellular manganese concentrations and uptake rates were related to the computed free manganese ion concentration and were independent of the total or chelated manganese concentration. Cellular manganese was constant at about 1 mmol liter/sup -1/ of cellular volume at free manganese ion concentrations of 10/sup -7/ /sup 6/-10/sup -6/ /sup 3/ mol liter/sup -1/ and decreased below this range. Manganese uptake rates followed saturation kinetics and V/sub max/, but not K/sub s/, varied with the free manganese ion concentration in the growth medium. V/sub max/ appeared to be under negative feedback control and increased with decreasing manganese ion concentration. Variations of up to 30-fold in this parameter seemed to be instrumental in limiting the variation in cellular manganese to a sixfold range despite a 1000-fold variation in free manganese ion concentration in the growth medium.

  14. Optical scatter imaging of cellular and mitochondrial swelling in brain tissue models of stroke

    NASA Astrophysics Data System (ADS)

    Johnson, Lee James

    2001-08-01

    then shown to correlate to mitochondrial swelling, as observed with electron microscopy. The system is finally used to study mitochondrial and cellular swelling. Evidence of the susceptibility of certain hippocampal regions, CA1 and the dentate gyrus, to exhibit mitochondrial swelling as the result of oxygen and glucose deprivation is presented. In addition, for the first time, the time course of mitochondrial swelling is seen. Finally, experiments with scatter imaging and measurement of nitric oxide with carbon fiber electrodes demonstrate a clear link between nitric oxide and cellular swelling. A potential mechanism of the action of nitric oxide is evaluated. Nitric oxide appears to act to cause cellular swelling without the release of glutamate. The use of targeted nitric oxide inhibitors may be useful for the reduction of edema.

  15. Summary of the DREAM8 Parameter Estimation Challenge: Toward Parameter Identification for Whole-Cell Models

    PubMed Central

    Karr, Jonathan R.; Williams, Alex H.; Zucker, Jeremy D.; Raue, Andreas; Steiert, Bernhard; Timmer, Jens; Kreutz, Clemens; Wilkinson, Simon; Allgood, Brandon A.; Bot, Brian M.; Hoff, Bruce R.; Kellen, Michael R.; Covert, Markus W.; Stolovitzky, Gustavo A.; Meyer, Pablo

    2015-01-01

    Whole-cell models that explicitly represent all cellular components at the molecular level have the potential to predict phenotype from genotype. However, even for simple bacteria, whole-cell models will contain thousands of parameters, many of which are poorly characterized or unknown. New algorithms are needed to estimate these parameters and enable researchers to build increasingly comprehensive models. We organized the Dialogue for Reverse Engineering Assessments and Methods (DREAM) 8 Whole-Cell Parameter Estimation Challenge to develop new parameter estimation algorithms for whole-cell models. We asked participants to identify a subset of parameters of a whole-cell model given the model’s structure and in silico “experimental” data. Here we describe the challenge, the best performing methods, and new insights into the identifiability of whole-cell models. We also describe several valuable lessons we learned toward improving future challenges. Going forward, we believe that collaborative efforts supported by inexpensive cloud computing have the potential to solve whole-cell model parameter estimation. PMID:26020786

  16. Games with fuzzy parameters

    NASA Astrophysics Data System (ADS)

    Messaoud, Deghdak

    2010-11-01

    In this paper, we study the existence of equilibrium in non-cooperative game with fuzzy parameters. We generalize te results of Larbani and Kacher(2008, 2009) in infinite dimentional spaces. The proof is based on the Browder-Fan fixed point theorem.

  17. Phenological Parameters Estimation Tool

    NASA Technical Reports Server (NTRS)

    McKellip, Rodney D.; Ross, Kenton W.; Spruce, Joseph P.; Smoot, James C.; Ryan, Robert E.; Gasser, Gerald E.; Prados, Donald L.; Vaughan, Ronald D.

    2010-01-01

    The Phenological Parameters Estimation Tool (PPET) is a set of algorithms implemented in MATLAB that estimates key vegetative phenological parameters. For a given year, the PPET software package takes in temporally processed vegetation index data (3D spatio-temporal arrays) generated by the time series product tool (TSPT) and outputs spatial grids (2D arrays) of vegetation phenological parameters. As a precursor to PPET, the TSPT uses quality information for each pixel of each date to remove bad or suspect data, and then interpolates and digitally fills data voids in the time series to produce a continuous, smoothed vegetation index product. During processing, the TSPT displays NDVI (Normalized Difference Vegetation Index) time series plots and images from the temporally processed pixels. Both the TSPT and PPET currently use moderate resolution imaging spectroradiometer (MODIS) satellite multispectral data as a default, but each software package is modifiable and could be used with any high-temporal-rate remote sensing data collection system that is capable of producing vegetation indices. Raw MODIS data from the Aqua and Terra satellites is processed using the TSPT to generate a filtered time series data product. The PPET then uses the TSPT output to generate phenological parameters for desired locations. PPET output data tiles are mosaicked into a Conterminous United States (CONUS) data layer using ERDAS IMAGINE, or equivalent software package. Mosaics of the vegetation phenology data products are then reprojected to the desired map projection using ERDAS IMAGINE

  18. The Parameters of Postmodernism.

    ERIC Educational Resources Information Center

    Zurbrugg, Nicholas

    Hypothesizing that the tendency to define postmodern culture negatively derives from overliteral and undercritical responses to European theorists, this book of essays identifies the wide parameters of postmodernism. The book demonstrates that the literary and artistic temper of the postmodern condition in Europe and America cannot adequately be…

  19. Exploring Cellular Interactions of Liposomes Using Protein Corona Fingerprints and Physicochemical Properties.

    PubMed

    Bigdeli, Arafeh; Palchetti, Sara; Pozzi, Daniela; Hormozi-Nezhad, Mohammad Reza; Baldelli Bombelli, Francesca; Caracciolo, Giulio; Mahmoudi, Morteza

    2016-03-22

    To control liposomes fate and transport upon contact with biofluids, it is essential to consider several parameters affecting the synthetic and biological identity of liposomes, as well as liposome-protein corona (PC) aspects. As a powerful tool in this data mining adventure, quantitative structure-activity relationship (QSAR) approach is used to correlate physicochemical properties of liposomes and their PC fingerprints to multiple quantified biological responses. In the present study, the relationship between cellular interactions of a set of structurally diverse liposomal formulations and their physicochemical and PC properties has been investigated via linear and nonlinear QSAR models. Significant parameters affecting cellular uptake and cell viability of liposomes in two important cancer cell lines (PC3 and HeLa) have been identified. The developed QSARs have the capacity to be implemented in advanced targeted delivery of liposomal drugs.

  20. Mapping of cellular iron using hyperspectral fluorescence imaging in a cellular model of Parkinson's disease

    NASA Astrophysics Data System (ADS)

    Oh, Eung Seok; Heo, Chaejeong; Kim, Ji Seon; Lee, Young Hee; Kim, Jong Min

    2013-05-01

    Parkinson's disease (PD) is characterized by progressive dopaminergic cell loss in the substantianigra (SN) and elevated iron levels demonstrated by autopsy and with 7-Tesla magnetic resonance imaging. Direct visualization of iron with live imaging techniques has not yet been successful. The aim of this study is to visualize and quantify the distribution of cellular iron using an intrinsic iron hyperspectral fluorescence signal. The 1-methyl-4-phenylpyridinium (MPP+)-induced cellular model of PD was established in SHSY5Y cells. The cells were exposed to iron by treatment with ferric ammonium citrate (FAC, 100 μM) for up to 6 hours. The hyperspectral fluorescence imaging signal of iron was examined usinga high- resolution dark-field optical microscope system with signal absorption for the visible/ near infrared (VNIR) spectral range. The 6-hour group showed heavy cellular iron deposition compared with the small amount of iron accumulation in the 1-hour group. The cellular iron was dispersed in a small, particulate form, whereas extracellular iron was detected in an aggregated form. In addition, iron particles were found to be concentrated on the cell membrane/edge of shrunken cells. The cellular iron accumulation readily occurred in MPP+-induced cells, which is consistent with previous studies demonstrating elevated iron levels in the SN in PD. This direct iron imaging methodology could be applied to analyze the physiological role of iron in PD, and its application might be expanded to various neurological disorders involving other metals, such as copper, manganese or zinc.

  1. AGCVIII Kinases: at the crossroads of cellular signaling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    AGCVIII kinases regulate diverse developmental and cellular processes in plants. As putative mediators of secondary messengers, AGCVIII kinases potentially integrate developmental and environmental cues into specific cellular responses through substrate phosphorylation. Here we discuss the functiona...

  2. Listening to the noise: random fluctuations reveal gene network parameters.

    PubMed

    Munsky, Brian; Trinh, Brooke; Khammash, Mustafa

    2009-01-01

    The cellular environment is abuzz with noise originating from the inherent random motion of reacting molecules in the living cell. In this noisy environment, clonal cell populations show cell-to-cell variability that can manifest significant phenotypic differences. Noise-induced stochastic fluctuations in cellular constituents can be measured and their statistics quantified. We show that these random fluctuations carry within them valuable information about the underlying genetic network. Far from being a nuisance, the ever-present cellular noise acts as a rich source of excitation that, when processed through a gene network, carries its distinctive fingerprint that encodes a wealth of information about that network. We show that in some cases the analysis of these random fluctuations enables the full identification of network parameters, including those that may otherwise be difficult to measure. This establishes a potentially powerful approach for the identification of gene networks and offers a new window into the workings of these networks.

  3. Final Technical Report

    SciTech Connect

    Sobecky, Patricia A; Taillefert, Martial

    2013-03-29

    This final technical report describes results and findings from a research project to examine the role of microbial phosphohydrolase enzymes in naturally occurring subsurface microorganisms for the purpose of promoting the immobilization of the radionuclide uranium through the production of insoluble uranium phosphate minerals. The research project investigated the microbial mechanisms and the physical and chemical processes promoting uranium biomineralization and sequestration in oxygenated subsurface soils. Uranium biomineralization under aerobic conditions can provide a secondary biobarrier strategy to immobilize radionuclides should the metal precipitates formed by microbial dissimilatory mechanisms remobilize due to a change in redox state.

  4. Prometheus Project final report

    NASA Technical Reports Server (NTRS)

    Taylor, Randall

    2005-01-01

    This Final Report serves as an executive summary of the Prometheus Project's activities and deliverables from November 2002 through September 2005. It focuses on the challenges from a technical and management perspective, what was different and innovative about this project, and identifies the major options, decisions, and accomplishments of the Project team as a whole. However, the details of the activities performed by DOE NR and its contractors will be documented separately in accordance with closeout requirements of the DOE NR and consistent with agreements between NASA and NR.

  5. Service dogs. Final rule.

    PubMed

    2012-09-05

    The Department of Veterans Affairs (VA) amends its regulations concerning veterans in need of service dogs. Under this final rule, VA will provide to veterans with visual, hearing, or mobility impairments benefits to support the use of a service dog as part of the management of such impairments. The benefits include assistance with veterinary care, travel benefits associated with obtaining and training a dog, and the provision, maintenance, and replacement of hardware required for the dog to perform the tasks necessary to assist such veterans.

  6. Scalable asynchronous execution of cellular automata

    NASA Astrophysics Data System (ADS)

    Folino, Gianluigi; Giordano, Andrea; Mastroianni, Carlo

    2016-10-01

    The performance and scalability of cellular automata, when executed on parallel/distributed machines, are limited by the necessity of synchronizing all the nodes at each time step, i.e., a node can execute only after the execution of the previous step at all the other nodes. However, these synchronization requirements can be relaxed: a node can execute one step after synchronizing only with the adjacent nodes. In this fashion, different nodes can execute different time steps. This can be a notable advantageous in many novel and increasingly popular applications of cellular automata, such as smart city applications, simulation of natural phenomena, etc., in which the execution times can be different and variable, due to the heterogeneity of machines and/or data and/or executed functions. Indeed, a longer execution time at a node does not slow down the execution at all the other nodes but only at the neighboring nodes. This is particularly advantageous when the nodes that act as bottlenecks vary during the application execution. The goal of the paper is to analyze the benefits that can be achieved with the described asynchronous implementation of cellular automata, when compared to the classical all-to-all synchronization pattern. The performance and scalability have been evaluated through a Petri net model, as this model is very useful to represent the synchronization barrier among nodes. We examined the usual case in which the territory is partitioned into a number of regions, and the computation associated with a region is assigned to a computing node. We considered both the cases of mono-dimensional and two-dimensional partitioning. The results show that the advantage obtained through the asynchronous execution, when compared to the all-to-all synchronous approach is notable, and it can be as large as 90% in terms of speedup.

  7. Applications of cellular fatty acid analysis.

    PubMed Central

    Welch, D F

    1991-01-01

    More than ever, new technology is having an impact on the tools of clinical microbiologists. The analysis of cellular fatty acids by gas-liquid chromatography (GLC) has become markedly more practical with the advent of the fused-silica capillary column, computer-controlled chromatography and data analysis, simplified sample preparation, and a commercially available GLC system dedicated to microbiological applications. Experience with applications in diagnostic microbiology ranges from substantial success in work with mycobacteria, legionellae, and nonfermentative gram-negative bacilli to minimal involvement with fungi and other nonbacterial agents. GLC is a good alternative to other means for the identification of mycobacteria or legionellae because it is rapid, specific, and independent of other specialized testing, e.g., DNA hybridization. Nonfermenters show features in their cellular fatty acid content that are useful in identifying species and, in some cases, subspecies. Less frequently encountered nonfermenters, including those belonging to unclassified groups, can ideally be characterized by GLC. Information is just beginning to materialize on the usefulness of cellular fatty acids for the identification of gram-positive bacteria and anaerobes, despite the traditional role of GLC in detecting metabolic products as an aid to identification of anaerobes. When species identification of coagulase-negative staphylococci is called for, GLC may offer an alternative to biochemical testing. Methods for direct analysis of clinical material have been developed, but in practical and economic terms they are not yet ready for use in the clinical laboratory. Direct analysis holds promise for detecting markers of infection due to an uncultivable agent or in clinical specimens that presently require cultures and prolonged incubation to yield an etiologic agent. PMID:1747860

  8. From Cellular Mechanotransduction to Biologically Inspired Engineering

    PubMed Central

    Ingber, Donald E.

    2010-01-01

    This article is based on a lecture I presented as the recipient of the 2009 Pritzker Distinguished Lecturer Award at the Biomedical Engineering Society annual meeting in October 2009. Here, I review more than thirty years of research from my laboratory, beginning with studies designed to test the theory that cells use tensegrity (tensional integrity) architecture to stabilize their shape and sense mechanical signals, which I believed to be critical for control of cell function and tissue development. Although I was trained as a cell biologist, I found that the tools I had at my disposal were insufficient to experimentally test these theories, and thus I ventured into engineering to find critical solutions. This path has been extremely fruitful as it has led to confirmation of the critical role that physical forces play in developmental control, as well as how cells sense and respond to mechanical signals at the molecular level through a process known as cellular mechanotransduction. Many of the predictions of the cellular tensegrity model relating to cell mechanical behaviors have been shown to be valid, and this vision of cell structure led to discovery of the central role that transmembrane adhesion receptors, such as integrins, and the cytoskeleton play in mechanosensing and mechanochemical conversion. In addition, these fundamental studies have led to significant unexpected technology fallout, including development of micromagnetic actuators for non-invasive control of cellular signaling, microfluidic systems as therapeutic extracorporeal devices for sepsis therapy, and new DNA-based nanobiotechnology approaches that permit construction of artificial tensegrities that mimic properties of living materials for applications in tissue engineering and regenerative medicine. PMID:20140519

  9. Model-selection-based approach for calculating cellular multiplicity of infection during virus colonization of multi-cellular hosts.

    PubMed

    Zwart, Mark P; Tromas, Nicolas; Elena, Santiago F

    2013-01-01

    The cellular multiplicity of infection (MOI) is a key parameter for describing the interactions between virions and cells, predicting the dynamics of mixed-genotype infections, and understanding virus evolution. Two recent studies have reported in vivo MOI estimates for Tobacco mosaic virus (TMV) and Cauliflower mosaic virus (CaMV), using sophisticated approaches to measure the distribution of two virus variants over host cells. Although the experimental approaches were similar, the studies employed different definitions of MOI and estimation methods. Here, new model-selection-based methods for calculating MOI were developed. Seven alternative models for predicting MOI were formulated that incorporate an increasing number of parameters. For both datasets the best-supported model included spatial segregation of virus variants over time, and to a lesser extent aggregation of virus-infected cells was also implicated. Three methods for MOI estimation were then compared: the two previously reported methods and the best-supported model. For CaMV data, all three methods gave comparable results. For TMV data, the previously reported methods both predicted low MOI values (range: 1.04-1.23) over time, whereas the best-supported model predicted a wider range of MOI values (range: 1.01-2.10) and an increase in MOI over time. Model selection can therefore identify suitable alternative MOI models and suggest key mechanisms affecting the frequency of coinfected cells. For the TMV data, this leads to appreciable differences in estimated MOI values.

  10. Evaluating acellular versus cellular perfusate composition during prolonged ex vivo lung perfusion after initial cold ischaemia for 24 hours.

    PubMed

    Becker, Simon; Steinmeyer, Jasmin; Avsar, Murat; Höffler, Klaus; Salman, Jawad; Haverich, Axel; Warnecke, Gregor; Ochs, Matthias; Schnapper, Anke

    2016-01-01

    Normothermic ex vivo lung perfusion (EVLP) has developed as a powerful technique to evaluate particularly marginal donor lungs prior to transplantation. In this study, acellular and cellular perfusate compositions were compared in an identical experimental setting as no consensus has been reached on a preferred technique yet. Porcine lungs underwent EVLP for 12 h on the basis of an acellular or a cellular perfusate composition after 24 h of cold ischaemia as defined organ stress. During perfusion, haemodynamic and respiratory parameters were monitored. After EVLP, the lung condition was assessed by light and transmission electron microscopy. Aerodynamic parameters did not show significant differences between groups and remained within the in vivo range during EVLP. Mean oxygenation indices were 491 ± 39 in the acellular group and 513 ± 53 in the cellular group. Groups only differed significantly in terms of higher pulmonary artery pressure and vascular resistance in the cellular group. Lung histology and ultrastructure were largely well preserved after prolonged EVLP and showed only minor structural alterations which were similarly present in both groups. Prolonged acellular and cellular EVLP for 12 h are both feasible with lungs prechallenged by ischaemic organ stress. Physiological and ultrastructural analysis showed no superiority of either acellular or cellular perfusate composition.

  11. Inferring Growth Control Mechanisms in Growing Multi-cellular Spheroids of NSCLC Cells from Spatial-Temporal Image Data

    PubMed Central

    Müller, Margareta; Vignon-Clementel, Irene E.; Drasdo, Dirk

    2016-01-01

    We develop a quantitative single cell-based mathematical model for multi-cellular tumor spheroids (MCTS) of SK-MES-1 cells, a non-small cell lung cancer (NSCLC) cell line, growing under various nutrient conditions: we confront the simulations performed with this model with data on the growth kinetics and spatial labeling patterns for cell proliferation, extracellular matrix (ECM), cell distribution and cell death. We start with a simple model capturing part of the experimental observations. We then show, by performing a sensitivity analysis at each development stage of the model that its complexity needs to be stepwise increased to account for further experimental growth conditions. We thus ultimately arrive at a model that mimics the MCTS growth under multiple conditions to a great extent. Interestingly, the final model, is a minimal model capable of explaining all data simultaneously in the sense, that the number of mechanisms it contains is sufficient to explain the data and missing out any of its mechanisms did not permit fit between all data and the model within physiological parameter ranges. Nevertheless, compared to earlier models it is quite complex i.e., it includes a wide range of mechanisms discussed in biological literature. In this model, the cells lacking oxygen switch from aerobe to anaerobe glycolysis and produce lactate. Too high concentrations of lactate or too low concentrations of ATP promote cell death. Only if the extracellular matrix density overcomes a certain threshold, cells are able to enter the cell cycle. Dying cells produce a diffusive growth inhibitor. Missing out the spatial information would not permit to infer the mechanisms at work. Our findings suggest that this iterative data integration together with intermediate model sensitivity analysis at each model development stage, provide a promising strategy to infer predictive yet minimal (in the above sense) quantitative models of tumor growth, as prospectively of other tissue

  12. Cellular Mechanisms of Central Nervous Modulation.

    DTIC Science & Technology

    1981-12-31

    Schofield, P.K. (1981) Mechanism of ionic homeostasis in the central nervous system of an insect. J. exp. Biol., 95, 61-73. Treherne, J.E., Schofield...P.K. & Lane, N.J. (1982) Physiological and ultra- structural evidence for an extracellular anion matrix in the central nervous system of an insect...AD-R147 875 CELLULAR MECHANISM1S OF CENTRAL NERVOUS tODULATION(U) I/i CAMBRIDGE UNIV (ENGLAND) DEPT OF ZOOLOGY J E TREHERNE 31 DEC 81 DAJA37-Si-C

  13. Effect of cellular mobility on immune response

    NASA Astrophysics Data System (ADS)

    Pandey, R. B.; Mannion, R.; Ruskin, H. J.

    2000-08-01

    Mobility of cell types in our HIV immune response model is subject to an intrinsic mobility and an explicit directed mobility, which is governed by Pmob. We investigate how restricting the explicit mobility, while maintaining the innate mobility of a viral-infected cell, affects the model's results. We find that increasing the explicit mobility of the immune system cells leads to viral dominance for certain levels of viral mutation. We conclude that increasing immune system cellular mobility indirectly increases the virus’ inherent mobility.

  14. Lightweight Cellular Metals with High Structural Efficiency

    DTIC Science & Technology

    2003-09-01

    10-2 10-1 0.01 0.1 Open-Cell Closed-Cell ERG Fraunhofer Alulight Alporas Cymat Relative Density, ρ* /ρ s Closed-Cell Open-Cell 10-4 10-3 10-2 10-1...0.01 0.1 Open-Cell Closed-Cell ERG Fraunhofer Alulight Alporas Cymat Relative Density, ρ* /ρ s Closed-Cell Open-Cell Stochastic Foams: Modulus and...Structures NATO ARW 22 Stiffness limited design at minimum weight Applications of Cellular Metals Cymat , Inc. Messiah College Beams (free area), columns

  15. Scaling behavior in probabilistic neuronal cellular automata.

    PubMed

    Manchanda, Kaustubh; Yadav, Avinash Chand; Ramaswamy, Ramakrishna

    2013-01-01

    We study a neural network model of interacting stochastic discrete two-state cellular automata on a regular lattice. The system is externally tuned to a critical point which varies with the degree of stochasticity (or the effective temperature). There are avalanches of neuronal activity, namely, spatially and temporally contiguous sites of activity; a detailed numerical study of these activity avalanches is presented, and single, joint, and marginal probability distributions are computed. At the critical point, we find that the scaling exponents for the variables are in good agreement with a mean-field theory.

  16. Immunometabolism: Cellular Metabolism Turns Immune Regulator*

    PubMed Central

    Loftus, Róisín M.; Finlay, David K.

    2016-01-01

    Immune cells are highly dynamic in terms of their growth, proliferation, and effector functions as they respond to immunological challenges. Different immune cells can adopt distinct metabolic configurations that allow the cell to balance its requirements for energy, molecular biosynthesis, and longevity. However, in addition to facilitating immune cell responses, it is now becoming clear that cellular metabolism has direct roles in regulating immune cell function. This review article describes the distinct metabolic signatures of key immune cells, explains how these metabolic setups facilitate immune function, and discusses the emerging evidence that intracellular metabolism has an integral role in controlling immune responses. PMID:26534957

  17. Immunometabolism: Cellular Metabolism Turns Immune Regulator.

    PubMed

    Loftus, Róisín M; Finlay, David K

    2016-01-01

    Immune cells are highly dynamic in terms of their growth, proliferation, and effector functions as they respond to immunological challenges. Different immune cells can adopt distinct metabolic configurations that allow the cell to balance its requirements for energy, molecular biosynthesis, and longevity. However, in addition to facilitating immune cell responses, it is now becoming clear that cellular metabolism has direct roles in regulating immune cell function. This review article describes the distinct metabolic signatures of key immune cells, explains how these metabolic setups facilitate immune function, and discusses the emerging evidence that intracellular metabolism has an integral role in controlling immune responses.

  18. Cellular and molecular mechanisms underlying muscular dystrophy

    PubMed Central

    2013-01-01

    The muscular dystrophies are a group of heterogeneous genetic diseases characterized by progressive degeneration and weakness of skeletal muscle. Since the discovery of the first muscular dystrophy gene encoding dystrophin, a large number of genes have been identified that are involved in various muscle-wasting and neuromuscular disorders. Human genetic studies complemented by animal model systems have substantially contributed to our understanding of the molecular pathomechanisms underlying muscle degeneration. Moreover, these studies have revealed distinct molecular and cellular mechanisms that link genetic mutations to diverse muscle wasting phenotypes. PMID:23671309

  19. Enantioselective cellular uptake of chiral semiconductor nanocrystals.

    PubMed

    Martynenko, I V; Kuznetsova, V A; Litvinov, I K; Orlova, A O; Maslov, V G; Fedorov, A V; Dubavik, A; Purcell-Milton, F; Gun'ko, Yu K; Baranov, A V

    2016-02-19

    The influence of the chirality of semiconductor nanocrystals, CdSe/ZnS quantum dots (QDs) capped with L- and D-cysteine, on the efficiency of their uptake by living Ehrlich Ascite carcinoma cells is studied by spectral- and time-resolved fluorescence microspectroscopy. We report an evident enantioselective process where cellular uptake of the L-Cys QDs is almost twice as effective as that of the D-Cys QDs. This finding paves the way for the creation of novel approaches to control the biological properties and behavior of nanomaterials in living cells.

  20. Elliptical Particle Clustering in Cellular Flows

    NASA Astrophysics Data System (ADS)

    Atis, Severine; Sapsis, Themistoklis; Peacock, Thomas

    2015-11-01

    The transport of finite-sized objects by fluid flows is relevant to a wide variety of phenomena, such as debris transport on the ocean surface or bacteria advection in fluid environment. The shape of the advected objects can strongly alter their coupling with the surrounding flow field, and hence, greatly affecting their dispersion by the flow. We present the results of investigations of the behavior of neutrally buoyant, elliptical particles in two-dimensional cellular flows. We find that their trajectories, and overall organization, are markedly different than for spherical particles, with clear clustering for the elliptical particles associated with vortices.

  1. Novel Immune-Modulating Cellular Vaccine for Prostate Cancer Immunotherapy

    DTIC Science & Technology

    2015-10-01

    AWARD NUMBER: W81XWH-13-1-0423 TITLE: Novel Immune-Modulating Cellular Vaccine for Prostate Cancer Immunotherapy PRINCIPAL INVESTIGATOR: Smita...SUBTITLE 5a. CONTRACT NUMBER W81XWH-13-1-0423 Novel Immune-Modulating Cellular Vaccine for Prostate Cancer Immunotherapy 5b. GRANT NUMBER 5c...immune modulation of CTLA4 and have generated a lead cellular therapy that will safely enhance vaccine -mediated immunity. This lead cellular

  2. Cellular Neural Network Models of Growth and Immune of Effector Cells Response to Cancer

    NASA Astrophysics Data System (ADS)

    Su, Yongmei; Min, Lequan

    Four reaction-diffusion cellular neural network (R-D CNN) models are set up based on the differential equation models for the growths of effector cells and cancer cells, and the model of the immune response to cancer proposed by Allison et al. The CNN models have different reaction-diffusion coefficients and coupling parameters. The R-D CNN models may provide possible quantitative interpretations, and are good in agreement with the in vitro experiment data reported by Allison et al.

  3. Validating Cellular Automata Lava Flow Emplacement Algorithms with Standard Benchmarks

    NASA Astrophysics Data System (ADS)

    Richardson, J. A.; Connor, L.; Charbonnier, S. J.; Connor, C.; Gallant, E.

    2015-12-01

    A major existing need in assessing lava flow simulators is a common set of validation benchmark tests. We propose three levels of benchmarks which test model output against increasingly complex standards. First, imulated lava flows should be morphologically identical, given changes in parameter space that should be inconsequential, such as slope direction. Second, lava flows simulated in simple parameter spaces can be tested against analytical solutions or empirical relationships seen in Bingham fluids. For instance, a lava flow simulated on a flat surface should produce a circular outline. Third, lava flows simulated over real world topography can be compared to recent real world lava flows, such as those at Tolbachik, Russia, and Fogo, Cape Verde. Success or failure of emplacement algorithms in these validation benchmarks can be determined using a Bayesian approach, which directly tests the ability of an emplacement algorithm to correctly forecast lava inundation. Here we focus on two posterior metrics, P(A|B) and P(¬A|¬B), which describe the positive and negative predictive value of flow algorithms. This is an improvement on less direct statistics such as model sensitivity and the Jaccard fitness coefficient. We have performed these validation benchmarks on a new, modular lava flow emplacement simulator that we have developed. This simulator, which we call MOLASSES, follows a Cellular Automata (CA) method. The code is developed in several interchangeable modules, which enables quick modification of the distribution algorithm from cell locations to their neighbors. By assessing several different distribution schemes with the benchmark tests, we have improved the performance of MOLASSES to correctly match early stages of the 2012-3 Tolbachik Flow, Kamchakta Russia, to 80%. We also can evaluate model performance given uncertain input parameters using a Monte Carlo setup. This illuminates sensitivity to model uncertainty.

  4. Environmental Monitoring using Measurements from Cellular Network Infrastructure

    NASA Astrophysics Data System (ADS)

    David, N.; Gao, O. H.

    2015-12-01

    Accurate measurements of atmospheric parameters at ground level are fundamentally essential for hazard warning, meteorological forecasting and for various applications in agriculture, hydrology, transportation and more. The accuracy of existing instruments, however, is often limited as a result of technical and practical constraints. Existing technologies such as satellite systems cover large areas but may experience lack of precision at near surface level. On the other hand, ground based in-situ sensors often suffer from low spatial representativity. In addition, these conventional monitoring instruments are costly to implement and maintain. At frequencies of tens of GHz, various atmospheric hydrometeors affect microwave beams, causing perturbations to radio signals. Consequently, commercial wireless links that constitute the infrastructure for data transport between cellular base stations can be considered as a built in environmental monitoring facility (Messer et al., Science, 2006). These microwave links are widely deployed worldwide at surface level altitudes and can provide measurements of various atmospheric phenomena. The implementation costs are minimal since the infrastructure is already situated in the field. This technique has been shown to be applicable for 2D rainfall monitoring (e.g. Overeem et al., PNAS, 2013; Liberman et al., AMT, 2014) and potentially for water vapor observations (David et al., ACP, 2009; Chwala et al., Atmos. Res., 2013). Moreover, it has been recently shown that the technology has strong potential for detection of fog and estimation of its intensity (David et al., JGR-Atmos., 2013; David et al., BAMS, 2014). The research conducted to this point forms the basis for the initiation of a research project in this newly emerging field at the School of Civil and Environmental Engineering of Cornell University. The presentation will provide insights into key capabilities of the novel approach. The potential to monitor various

  5. Impact of ionic current variability on human ventricular cellular electrophysiology.

    PubMed

    Romero, Lucía; Pueyo, Esther; Fink, Martin; Rodríguez, Blanca

    2009-10-01

    Abnormalities in repolarization and its rate dependence are known to be related to increased proarrhythmic risk. A number of repolarization-related electrophysiological properties are commonly used as preclinical biomarkers of arrhythmic risk. However, the variability and complexity of repolarization mechanisms make the use of cellular biomarkers to predict arrhythmic risk preclinically challenging. Our goal is to investigate the role of ionic current properties and their variability in modulating cellular biomarkers of arrhythmic risk to improve risk stratification and identification in humans. A systematic investigation into the sensitivity of the main preclinical biomarkers of arrhythmic risk to changes in ionic current conductances and kinetics was performed using computer simulations. Four stimulation protocols were applied to the ten Tusscher and Panfilov human ventricular model to quantify the impact of +/-15 and +/-30% variations in key model parameters on action potential (AP) properties, Ca(2+) and Na(+) dynamics, and their rate dependence. Simulations show that, in humans, AP duration is moderately sensitive to changes in all repolarization current conductances and in L-type Ca(2+) current (I(CaL)) and slow component of the delayed rectifier current (I(Ks)) inactivation kinetics. AP triangulation, however, is strongly dependent only on inward rectifier K(+) current (I(K1)) and delayed rectifier current (I(Kr)) conductances. Furthermore, AP rate dependence (i.e., AP duration rate adaptation and restitution properties) and intracellular Ca(2+) and Na(+) levels are highly sensitive to both I(CaL) and Na(+)/K(+) pump current (I(NaK)) properties. This study provides quantitative insights into the sensitivity of preclinical biomarkers of arrhythmic risk to variations in ionic current properties in humans. The results show the importance of sensitivity analysis as a powerful method for the in-depth validation of mathematical models in cardiac electrophysiology.

  6. A Cellular Automata-Based Mathematical Model for Thymocyte Development

    PubMed Central

    Souza-e-Silva, Hallan; Savino, Wilson; Feijóo, Raúl A.; Vasconcelos, Ana Tereza Ribeiro

    2009-01-01

    Intrathymic T cell development is an important process necessary for the normal formation of cell-mediated immune responses. Importantly, such a process depends on interactions of developing thymocytes with cellular and extracellular elements of the thymic microenvironment. Additionally, it includes a series of oriented and tunely regulated migration events, ultimately allowing mature cells to cross endothelial barriers and leave the organ. Herein we built a cellular automata-based mathematical model for thymocyte migration and development. The rules comprised in this model take into account the main stages of thymocyte development, two-dimensional sections of the normal thymic microenvironmental network, as well as the chemokines involved in intrathymic cell migration. Parameters of our computer simulations with further adjusted to results derived from previous experimental data using sub-lethally irradiated mice, in which thymus recovery can be evaluated. The model fitted with the increasing numbers of each CD4/CD8-defined thymocyte subset. It was further validated since it fitted with the times of permanence experimentally ascertained in each CD4/CD8-defined differentiation stage. Importantly, correlations using the whole mean volume of young normal adult mice revealed that the numbers of cells generated in silico with the mathematical model fall within the range of total thymocyte numbers seen in these animals. Furthermore, simulations made with a human thymic epithelial network using the same mathematical model generated similar profiles for temporal evolution of thymocyte developmental stages. Lastly, we provided in silico evidence that the thymus architecture is important in the thymocyte development, since changes in the epithelial network result in different theoretical profiles for T cell development/migration. This model likely can be used to predict thymocyte evolution following therapeutic strategies designed for recovery of the thymus in diseases

  7. Cosmology Without Finality

    NASA Astrophysics Data System (ADS)

    Mahootian, F.

    2009-12-01

    The rapid convergence of advancing sensor technology, computational power, and knowledge discovery techniques over the past decade has brought unprecedented volumes of astronomical data together with unprecedented capabilities of data assimilation and analysis. A key result is that a new, data-driven "observational-inductive'' framework for scientific inquiry is taking shape and proving viable. The anticipated rise in data flow and processing power will have profound effects, e.g., confirmations and disconfirmations of existing theoretical claims both for and against the big bang model. But beyond enabling new discoveries can new data-driven frameworks of scientific inquiry reshape the epistemic ideals of science? The history of physics offers a comparison. The Bohr-Einstein debate over the "completeness'' of quantum mechanics centered on a question of ideals: what counts as science? We briefly examine lessons from that episode and pose questions about their applicability to cosmology. If the history of 20th century physics is any indication, the abandonment of absolutes (e.g., space, time, simultaneity, continuity, determinacy) can produce fundamental changes in understanding. The classical ideal of science, operative in both physics and cosmology, descends from the European Enlightenment. This ideal has for over 200 years guided science to seek the ultimate order of nature, to pursue the absolute theory, the "theory of everything.'' But now that we have new models of scientific inquiry powered by new technologies and driven more by data than by theory, it is time, finally, to relinquish dreams of a "final'' theory.

  8. 47 CFR 22.905 - Channels for cellular service.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Channels for cellular service. 22.905 Section... MOBILE SERVICES Cellular Radiotelephone Service § 22.905 Channels for cellular service. The following...) Channel Block A: 869-880 MHz paired with 824-835 MHz, and 890-891.5 MHz paired with 845-846.5 MHz....

  9. 47 CFR 22.905 - Channels for cellular service.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Channels for cellular service. 22.905 Section... MOBILE SERVICES Cellular Radiotelephone Service § 22.905 Channels for cellular service. The following...) Channel Block A: 869-880 MHz paired with 824-835 MHz, and 890-891.5 MHz paired with 845-846.5 MHz....

  10. Feasibility investigation of a cellularly organized data processor

    NASA Technical Reports Server (NTRS)

    Minnick, R. C.; Jump, J. R.; Arnold, R. G.; Beirne, J. M.

    1972-01-01

    The application of cellular arrays to NASA missions was studied. Cellular arrays are iterative logical and memory structures which can be programmed to accomplish a wide variety of logical tasks. Used in long-duration space missions, spare cellular arrays can be remotely programmed to replace faulty logical subsystems as the need arises.

  11. 47 CFR 22.901 - Cellular service requirements and limitations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SERVICES PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.901 Cellular service requirements and... operates in compliance with this section. (a) Each cellular system must provide either mobile service, fixed service, or a combination of mobile and fixed service, subject to the requirements,...

  12. Voluntary accreditation of cellular therapies: Foundation for the Accreditation of Cellular Therapy (FACT).

    PubMed

    Warkentin, P I

    2003-01-01

    Voluntary accreditation of cells, tissues, and cellular and tissue-based products intended for human transplantation is an important mechanism for improving quality in cellular therapy. The Foundation for the Accreditation of Cellular Therapy (FACT) has developed and implemented programs of voluntary inspection and accreditation for hematopoietic cellular therapy, and for cord blood banking. These programs are based on the standards of the clinical and laboratory professionals of the American Society of Blood and Marrow Transplantation (ASBMT), the International Society for Cellular Therapy (ISCT), and NETCORD. FACT has collaborated with European colleagues in the development of the Joint Accreditation Committee in Europe (jACIE). FACT has published standards documents, a guidance manual, accreditation checklists, and inspection documents; and has trained as inspectors over 300 professionals active in the field. All inspectors have a minimum of 5 years' experience in the area they inspect. Since the incorporation of FACT in 1996, 215 hematopoietic progenitor cell facilities have applied for FACT accreditation. Of these facilities, 113 are fully accredited; the others are in the process of document submission or inspection. Significant opportunities and challenges exist for FACT in the future, including keeping standards and guidance materials current and relevant, recruiting and retaining expert inspectors, and establishing collaborations to develop standards and accreditation systems for new cellular products. The continuing dialogue with the Food and Drug Administration (FDA) is also important to ensure that they are aware of the accomplishments of voluntary accreditation, and keep FACT membership alerted to FDA intentions for the future. Other potential avenues of communication and cooperation with FDA and other regulatory agencies are being investigated and evaluated.

  13. Membrane permeable luminescent metal complexes for cellular imaging

    NASA Astrophysics Data System (ADS)

    Neugebauer, Ute; Cosgrave, Lynda; Pellegrin, Yann; Devocelle, Marc; Forster, Robert J.; Keyes, Tia E.

    2012-06-01

    The spectroscopic and photophysical properties of ruthenium polypyridyl polypeptide conjugates of the type [Ru(bpy)2PIC-Argn]n+2+, where bpy is 2,2-bipyridyl (bpy), PIC is 2-(4-carboxyphenyl)imidazo[4,5- f][1,10]phenanthroline and PIC-Argn is this ligand peptide bonded to polyarginine where n is 5 or 8, is described. The resonance Raman spectroscopy of the peptide conjugated complex and parent are strongly pH dependent and demonstrate a switch of lowest energy charge transfer transition between bpy and pic ligands as s function of pH. The pKa of the imidazole ring on the complex is obtained from resonance Raman spectroscopy as 7.8 +/- 0.2. The luminescence lifetime of the complex is strongly oxygen dependent and a Stern-Volmer plot of O2 quenching for [Ru(bpy)2(PIC-Arg8)]10+ yielded a KSV value of 2300 +/- 420 M-1 which was independent of pH over the range 2 to 11. The complexes, because of their large Stokes shifts can, uniquely, be used under identical conditions of probe concentration and excitation wavelength for resonance Raman and luminescence cellular imaging. Cellular imaging was conducted using SP2 myeloma cells which confirmed that the [Ru(bpy)2(PIC-Arg8)]10+ is readily taken up by mammalian cells although the parent and pentarginine analogues are not membrane permeable. Preliminary examples of multi-parameter imaging using these probes were presented. Resonance Raman maps of [Ru(bpy)2(PIC-Arg8)]10+ within living myeloma cells showed on the basis of spectral discrimination, attributed to pH, three distinct regions of the cell could be identified, ascribed to the nucleus, the cytoplasm and the membranes. Luminescence lifetime imaging showed quite large variations in the probe lifetime within the living cell which was tentatively ascribed to variation in O2 concentration about the cell. Preliminary estimates of O2 concentration were made and it was found that the membranes, both inner and outer are the most O2 rich regions of the cell. Overall, we propose

  14. Cellular chromophores and signaling in low level light therapy

    NASA Astrophysics Data System (ADS)

    Hamblin, Michael R.; Demidova-Rice, Tatiana N.

    2007-02-01

    The use of low levels of visible or near infrared light (LLLT) for reducing pain, inflammation and edema, promoting healing of wounds, deeper tissues and nerves, and preventing tissue damage by reducing cellular apoptosis has been known for almost forty years since the invention of lasers. Originally thought to be a peculiar property of laser light (soft or cold lasers), the subject has now broadened to include photobiomodulation and photobiostimulation using non-coherent light. Despite many reports of positive findings from experiments conducted in vitro, in animal models and in randomized controlled clinical trials, LLLT remains controversial. This likely is due to two main reasons; firstly the biochemical mechanisms underlying the positive effects are incompletely understood, and secondly the complexity of rationally choosing amongst a large number of illumination parameters such as wavelength, fluence, power density, pulse structure and treatment timing has led to the publication of a number of negative studies as well as many positive ones. In recent years major advances have been made in understanding the mechanisms that operate at the cellular and tissue levels during LLLT. Mitochondria are thought to be the main site for the initial effects of light and specifically cytochrome c oxidase that has absorption peaks in the red and near infrared regions of the electromagnetic spectrum matches the action spectra of LLLT effects. The discovery that cells employ nitric oxide (NO) synthesized in the mitochondria by neuronal nitric oxide synthase, to regulate respiration by competitive binding to the oxygen binding of cytochrome c oxidase, now suggests how LLLT can affect cell metabolism. If LLLT photodissociates inhibitory NO from cytochrome c oxidase, this would explain increased ATP production, modulation of reactive oxygen species, reduction and prevention of apoptosis, stimulation of angiogenesis, increase of blood flow and induction of transcription factors. In

  15. Physical Parameter Eclipse Mapping

    NASA Astrophysics Data System (ADS)

    Vrielmann, S.

    The tomographic method Physical Parameter Eclipse Mapping is a tool to reconstruct spatial distributions of physical parameters (like temperatures and surface densities) in accretion discs of cataclysmic variables. After summarizing the method, we apply it to multi-colour eclipse light curves of various dwarf novae and nova-likes like VZ Scl, IP Peg in outburst, UU Aqr, V2051 Oph and HT Cas in order to derive the temperatures (and surface densities) in the disc, the white dwarf temperature, the disc size, the effective temperatures and the viscosities. The results allows us to establish or refine a physical model for the accretion disc. Our maps of HT Cas and V 2051Oph, for example, indicate that the (quiescent) disc must be structured into a cool, optically thick inner disc sandwiched by hot, optically thin chromospheres. In addition, the disc of HT Cas must be patchy with a covering factor of about 40% caused by magnetic activity in the disc.

  16. Military display performance parameters

    NASA Astrophysics Data System (ADS)

    Desjardins, Daniel D.; Meyer, Frederick

    2012-06-01

    The military display market is analyzed in terms of four of its segments: avionics, vetronics, dismounted soldier, and command and control. Requirements are summarized for a number of technology-driving parameters, to include luminance, night vision imaging system compatibility, gray levels, resolution, dimming range, viewing angle, video capability, altitude, temperature, shock and vibration, etc., for direct-view and virtual-view displays in cockpits and crew stations. Technical specifications are discussed for selected programs.

  17. Blood biochemical and cellular changes during a decompression procedure involving eight hours of oxygen prebreathing

    NASA Technical Reports Server (NTRS)

    Jauchem, J. R.

    1989-01-01

    Chemical and cellular parameters were measured in human subjects before and after exposure to a decompression schedule involving 8 h of oxygen prebreathing. The exposure was designed to simulate space-flight extravehicular activity (EVA) for 6 h. Several statistically significant changes in blood parameters were observed following the exposure: increases in calcium, magnesium, osmolality, low-density lipoprotein cholesterol, monocytes, and prothrombin time, and decreases in chloride, creatine phosphokinase and eosinophils. The changes, however, were small in magnitude and blood factor levels remained within normal clinical ranges. Thus, the decompression profile used in this study is not likely to result in blood changes that would pose a threat to astronauts during EVA.

  18. Fabrication methods of micrometallic closed cellular materials

    NASA Astrophysics Data System (ADS)

    Kishimoto, Satoshi; Shinya, Norio

    2006-03-01

    A method to fabricate the metallic closed cellular material has been developed. Powder particles of polymer coated with a nickel-phosphorus alloy layer using electro-less plating were pressed into pellets and sintered at high temperatures by a furnace and a spark plasma sintering (SPS) system. A metallic closed cellular material containing different materials from that of cell walls was then fabricated. The mechanical properties of this material were measured. The results of the compressive tests show that this material has the different stress-strain curves among the specimens that have different thickness of the cell walls and the sintering temperatures of the specimens affect the compressive strength of each specimen. Also, it seems that the results of the compressive tests show that this material has high-energy absorption and Young's modulus of this material depends on the thickness of the cell walls and the sintering temperature. These obtained results emphasize that this material can be utilized as energy absorbing material and passive damping material.

  19. Cellular and molecular approaches to memory storage.

    PubMed

    Laroche, S

    2000-01-01

    There has been nearly a century of interest in the idea that information is stored in the brain as changes in the efficacy of synaptic connections on neurons that are activated during learning. The discovery and detailed report of the phenomenon generally known as long-term potentiation opened a new chapter in the study of synaptic plasticity in the vertebrate brain, and this form of synaptic plasticity has now become the dominant model in the search for the cellular bases of learning and memory. To date, considerable progress has been made in understanding the cellular and molecular mechanisms underlying synaptic plasticity and in identifying the neural systems which express it. In parallel, the hypothesis that the mechanisms underlying synaptic plasticity are activated during learning and serve learning and memory has gained much empirical support. Accumulating evidence suggests that the rapid activation of the genetic machinery is a key mechanism underlying the enduring modification of neural networks required for the laying down of memory. These advances are reviewed below.

  20. Diabetes mellitus: channeling care through cellular discovery.

    PubMed

    Maiese, Kenneth; Shang, Yan Chen; Chong, Zhao Zhong; Hou, Jinling

    2010-02-01

    Diabetes mellitus (DM) impacts a significant portion of the world's population and care for this disorder places an economic burden on the gross domestic product for any particular country. Furthermore, both Type 1 and Type 2 DM are becoming increasingly prevalent and there is increased incidence of impaired glucose tolerance in the young. The complications of DM are protean and can involve multiple systems throughout the body that are susceptible to the detrimental effects of oxidative stress and apoptotic cell injury. For these reasons, innovative strategies are necessary for the implementation of new treatments for DM that are generated through the further understanding of cellular pathways that govern the pathological consequences of DM. In particular, both the precursor for the coenzyme beta-nicotinamide adenine dinucleotide (NAD(+)), nicotinamide, and the growth factor erythropoietin offer novel platforms for drug discovery that involve cellular metabolic homeostasis and inflammatory cell control. Interestingly, these agents and their tightly associated pathways that consist of cell cycle regulation, protein kinase B, forkhead transcription factors, and Wnt signaling also function in a broader sense as biomarkers for disease onset and progression.

  1. Estimation of cellular fabric in embryonic epithelia.

    PubMed

    Iles, Peter J W; Brodland, G Wayne; Clausi, David A; Puddister, Shannon M

    2007-02-01

    Recent computational and analytical studies have shown that cellular fabric-as embodied by average cell size, aspect ratio and orientation-is a key indicator of the stresses acting in an embryonic epithelium. Cellular fabric in real embryonic tissues could not previously be measured automatically because the cell boundaries tend to be poorly defined, significant lighting and cell pigmentation differences occur and tissues contain a variety of cell geometries. To overcome these difficulties, four algorithms were developed: least squares ellipse fitting (LSEF), area moments (AM), correlation and axes search (CAS) and Gabor filters (GF). The AM method was found to be the most reliable of these methods, giving typical cell size, aspect ratio and orientation errors of 18%, 0.10 and 7.4 degrees, respectively, when evaluated against manually segmented images. The power of the AM algorithm to provide new insights into the mechanics of morphogenesis is demonstrated through a brief investigation of gastrulation, where fabric data suggest that key gastrulation movements are driven by epidermal tensions circumferential to the blastopore.

  2. Cellular Prion Protein: From Physiology to Pathology

    PubMed Central

    Yusa, Sei-ichi; Oliveira-Martins, José B.; Sugita-Konishi, Yoshiko; Kikuchi, Yutaka

    2012-01-01

    The human cellular prion protein (PrPC) is a glycosylphosphatidylinositol (GPI) anchored membrane glycoprotein with two N-glycosylation sites at residues 181 and 197. This protein migrates in several bands by Western blot analysis (WB). Interestingly, PNGase F treatment of human brain homogenates prior to the WB, which is known to remove the N-glycosylations, unexpectedly gives rise to two dominant bands, which are now known as C-terminal (C1) and N-terminal (N1) fragments. This resembles the β-amyloid precursor protein (APP) in Alzheimer disease (AD), which can be physiologically processed by α-, β-, and γ-secretases. The processing of APP has been extensively studied, while the identity of the cellular proteases involved in the proteolysis of PrPC and their possible role in prion biology has remained limited and controversial. Nevertheless, there is a strong correlation between the neurotoxicity caused by prion proteins and the blockade of their normal proteolysis. For example, expression of non-cleavable PrPC mutants in transgenic mice generates neurotoxicity, even in the absence of infectious prions, suggesting that PrPC proteolysis is physiologically and pathologically important. As many mouse models of prion diseases have recently been developed and the knowledge about the proteases responsible for the PrPC proteolysis is accumulating, we examine the historical experimental evidence and highlight recent studies that shed new light on this issue. PMID:23202518

  3. Optogenetic control of cellular forces and mechanotransduction

    PubMed Central

    Valon, Léo; Marín-Llauradó, Ariadna; Wyatt, Thomas; Charras, Guillaume; Trepat, Xavier

    2017-01-01

    Contractile forces are the end effectors of cell migration, division, morphogenesis, wound healing and cancer invasion. Here we report optogenetic tools to upregulate and downregulate such forces with high spatiotemporal accuracy. The technology relies on controlling the subcellular activation of RhoA using the CRY2/CIBN light-gated dimerizer system. We fused the catalytic domain (DHPH domain) of the RhoA activator ARHGEF11 to CRY2-mCherry (optoGEF-RhoA) and engineered its binding partner CIBN to bind either to the plasma membrane or to the mitochondrial membrane. Translocation of optoGEF-RhoA to the plasma membrane causes a rapid and local increase in cellular traction, intercellular tension and tissue compaction. By contrast, translocation of optoGEF-RhoA to mitochondria results in opposite changes in these physical properties. Cellular changes in contractility are paralleled by modifications in the nuclear localization of the transcriptional regulator YAP, thus showing the ability of our approach to control mechanotransductory signalling pathways in time and space. PMID:28186127

  4. Conformational Sampling of Peptides in Cellular Environments☆

    PubMed Central

    Tanizaki, Seiichiro; Clifford, Jacob; Connelly, Brian D.; Feig, Michael

    2008-01-01

    Abstract Biological systems provide a complex environment that can be understood in terms of its dielectric properties. High concentrations of macromolecules and cosolvents effectively reduce the dielectric constant of cellular environments, thereby affecting the conformational sampling of biomolecules. To examine this effect in more detail, the conformational preference of alanine dipeptide, poly-alanine, and melittin in different dielectric environments is studied with computer simulations based on recently developed generalized Born methodology. Results from these simulations suggest that extended conformations are favored over α-helical conformations at the dipeptide level at and below dielectric constants of 5–10. Furthermore, lower-dielectric environments begin to significantly stabilize helical structures in poly-alanine at ɛ = 20. In the more complex peptide melittin, different dielectric environments shift the equilibrium between two main conformations: a nearly fully extended helix that is most stable in low dielectrics and a compact, V-shaped conformation consisting of two helices that is preferred in higher dielectric environments. An additional conformation is only found to be significantly populated at intermediate dielectric constants. Good agreement with previous studies of different peptides in specific, less-polar solvent environments, suggest that helix stabilization and shifts in conformational preferences in such environments are primarily due to a reduced dielectric environment rather than specific molecular details. The findings presented here make predictions of how peptide sampling may be altered in dense cellular environments with reduced dielectric response. PMID:17905846

  5. Proteasome Modulates Mitochondrial Function During Cellular Senescence

    PubMed Central

    Torres, Claudio A.; Perez, Viviana I.

    2009-01-01

    Proteasome plays fundamental roles in the removal of oxidized proteins and in the normal degradation of short-lived proteins. Previously we have provided evidences that the impairment in proteasome observed during the replicative senescence of human fibroblasts has significant effects on MAPK signaling, proliferation, life span, senescent phenotype and protein oxidative status. These studies have demonstrated that proteasome inhibition and replicative senescence caused accumulation of intracellular protein carbonyl content. In this study, we have investigated the mechanisms by which proteasome dysfunction modulates protein oxidation during cellular senescence. The results indicate that proteasome inhibition during replicative senescence have significant effects on the intra and extracellular ROS production in vitro. The data also show that ROS impaired the proteasome function, which is partially reversible by antioxidants. Increases in ROS after proteasome inhibition correlated with a significant negative effect on the activity of most mitochondrial electron transporters. We propose that failures in proteasome during cellular senescence lead to mitochondrial dysfunction, ROS production and oxidative stress. Furthermore, it is likely that changes in proteasome dynamics could generate a pro-oxidative condition at the immediate extracellular microenvironment that could cause tissue injury during aging, in vivo. PMID:17976388

  6. Elements of the cellular metabolic structure

    PubMed Central

    De la Fuente, Ildefonso M.

    2015-01-01

    A large number of studies have demonstrated the existence of metabolic covalent modifications in different molecular structures, which are able to store biochemical information that is not encoded by DNA. Some of these covalent mark patterns can be transmitted across generations (epigenetic changes). Recently, the emergence of Hopfield-like attractor dynamics has been observed in self-organized enzymatic networks, which have the capacity to store functional catalytic patterns that can be correctly recovered by specific input stimuli. Hopfield-like metabolic dynamics are stable and can be maintained as a long-term biochemical memory. In addition, specific molecular information can be transferred from the functional dynamics of the metabolic networks to the enzymatic activity involved in covalent post-translational modulation, so that determined functional memory can be embedded in multiple stable molecular marks. The metabolic dynamics governed by Hopfield-type attractors (functional processes), as well as the enzymatic covalent modifications of specific molecules (structural dynamic processes) seem to represent the two stages of the dynamical memory of cellular metabolism (metabolic memory). Epigenetic processes appear to be the structural manifestation of this cellular metabolic memory. Here, a new framework for molecular information storage in the cell is presented, which is characterized by two functionally and molecularly interrelated systems: a dynamic, flexible and adaptive system (metabolic memory) and an essentially conservative system (genetic memory). The molecular information of both systems seems to coordinate the physiological development of the whole cell. PMID:25988183

  7. Silica Nanoconstruct Cellular Toleration Threshold In Vitro

    PubMed Central

    Herd, Heather L.; Malugin, Alexander; Ghandehari, Hamidreza

    2011-01-01

    The influence of geometry of silica nanomaterials on cellular uptake and toxicity on epithelial and phagocytic cells was studied. Three types of amine-terminated silica nanomaterials were prepared and characterized via the modified Stober method, namely spheres (178±27 nm), worms (232±22 nm × 1348±314 nm) and cylinders (214±29 nm × 428±66 nm). The findings of the study suggest that in this size range and for the cell types studied, geometry does not play a dominant role in the modes of toxicity and uptake of these particles. Rather, a concentration threshold and cell type dependent toxicity of all particle types was observed. This correlated with confocal microscopy observations, as all nanomaterials were observed to be taken up in both cell types, with a greater extent in phagocytic cells. It must be noted that there appears to be a concentration threshold at ~100 µg/mL, below which there is limited to no impact of the nanoparticles on membrane integrity, mitochondrial function, phagocytosis or cell death. Analysis of cell morphology by transmission electron microscopy, colocalization experiments with intracellular markers and Western Blot results provide evidence of potential involvement of lysosomal escape, autophagic like activity, compartmental fusion and recycling in response to intracellular nanoparticle accumulation. These processes could be involved in cellular coping or defense mechanisms. The manipulation of physicochemical properties to enhance or reduce toxicity paves the way for the safe design of silica-based nanoparticles for use in nanomedicine. PMID:21342660

  8. Network motifs modulate druggability of cellular targets

    PubMed Central

    Wu, Fan; Ma, Cong; Tan, Cheemeng

    2016-01-01

    Druggability refers to the capacity of a cellular target to be modulated by a small-molecule drug. To date, druggability is mainly studied by focusing on direct binding interactions between a drug and its target. However, druggability is impacted by cellular networks connected to a drug target. Here, we use computational approaches to reveal basic principles of network motifs that modulate druggability. Through quantitative analysis, we find that inhibiting self-positive feedback loop is a more robust and effective treatment strategy than inhibiting other regulations, and adding direct regulations to a drug-target generally reduces its druggability. The findings are explained through analytical solution of the motifs. Furthermore, we find that a consensus topology of highly druggable motifs consists of a negative feedback loop without any positive feedback loops, and consensus motifs with low druggability have multiple positive direct regulations and positive feedback loops. Based on the discovered principles, we predict potential genetic targets in Escherichia coli that have either high or low druggability based on their network context. Our work establishes the foundation toward identifying and predicting druggable targets based on their network topology. PMID:27824147

  9. Piezoelectric nanoribbons for monitoring cellular deformations

    NASA Astrophysics Data System (ADS)

    Nguyen, Thanh D.; Deshmukh, Nikhil; Nagarah, John M.; Kramer, Tal; Purohit, Prashant K.; Berry, Michael J.; McAlpine, Michael C.

    2012-09-01

    Methods for probing mechanical responses of mammalian cells to electrical excitations can improve our understanding of cellular physiology and function. The electrical response of neuronal cells to applied voltages has been studied in detail, but less is known about their mechanical response to electrical excitations. Studies using atomic force microscopes (AFMs) have shown that mammalian cells exhibit voltage-induced mechanical deflections at nanometre scales, but AFM measurements can be invasive and difficult to multiplex. Here we show that mechanical deformations of neuronal cells in response to electrical excitations can be measured using piezoelectric PbZrxTi1-xO3 (PZT) nanoribbons, and we find that cells deflect by 1 nm when 120 mV is applied to the cell membrane. The measured cellular forces agree with a theoretical model in which depolarization caused by an applied voltage induces a change in membrane tension, which results in the cell altering its radius so that the pressure remains constant across the membrane. We also transfer arrays of PZT nanoribbons onto a silicone elastomer and measure mechanical deformations on a cow lung that mimics respiration. The PZT nanoribbons offer a minimally invasive and scalable platform for electromechanical biosensing.

  10. Enhanced Viral Replication by Cellular Replicative Senescence

    PubMed Central

    Kim, Ji-Ae; Seong, Rak-Kyun

    2016-01-01

    Cellular replicative senescence is a major contributing factor to aging and to the development and progression of aging-associated diseases. In this study, we sought to determine viral replication efficiency of influenza virus (IFV) and Varicella Zoster Virus (VZV) infection in senescent cells. Primary human bronchial epithelial cells (HBE) or human dermal fibroblasts (HDF) were allowed to undergo numbers of passages to induce replicative senescence. Induction of replicative senescence in cells was validated by positive senescence-associated β-galactosidase staining. Increased susceptibility to both IFV and VZV infection was observed in senescent HBE and HDF cells, respectively, resulting in higher numbers of plaque formation, along with the upregulation of major viral antigen expression than that in the non-senescent cells. Interestingly, mRNA fold induction level of virus-induced type I interferon (IFN) was attenuated by senescence, whereas IFN-mediated antiviral effect remained robust and potent in virus-infected senescent cells. Additionally, we show that a longevity-promoting gene, sirtuin 1 (SIRT1), has antiviral role against influenza virus infection. In conclusion, our data indicate that enhanced viral replication by cellular senescence could be due to senescence-mediated reduction of virus-induced type I IFN expression. PMID:27799874

  11. A cellular automata model of bone formation.

    PubMed

    Van Scoy, Gabrielle K; George, Estee L; Opoku Asantewaa, Flora; Kerns, Lucy; Saunders, Marnie M; Prieto-Langarica, Alicia

    2017-04-01

    Bone remodeling is an elegantly orchestrated process by which osteocytes, osteoblasts and osteoclasts function as a syncytium to maintain or modify bone. On the microscopic level, bone consists of cells that create, destroy and monitor the bone matrix. These cells interact in a coordinated manner to maintain a tightly regulated homeostasis. It is this regulation that is responsible for the observed increase in bone gain in the dominant arm of a tennis player and the observed increase in bone loss associated with spaceflight and osteoporosis. The manner in which these cells interact to bring about a change in bone quality and quantity has yet to be fully elucidated. But efforts to understand the multicellular complexity can ultimately lead to eradication of metabolic bone diseases such as osteoporosis and improved implant longevity. Experimentally validated mathematical models that simulate functional activity and offer eventual predictive capabilities offer tremendous potential in understanding multicellular bone remodeling. Here we undertake the initial challenge to develop a mathematical model of bone formation validated with in vitro data obtained from osteoblastic bone cells induced to mineralize and quantified at 26 days of culture. A cellular automata model was constructed to simulate the in vitro characterization. Permutation tests were performed to compare the distribution of the mineralization in the cultures and the distribution of the mineralization in the mathematical models. The results of the permutation test show the distribution of mineralization from the characterization and mathematical model come from the same probability distribution, therefore validating the cellular automata model.

  12. Mechanisms of cellular invasion by intracellular parasites.

    PubMed

    Walker, Dawn M; Oghumu, Steve; Gupta, Gaurav; McGwire, Bradford S; Drew, Mark E; Satoskar, Abhay R

    2014-04-01

    Numerous disease-causing parasites must invade host cells in order to prosper. Collectively, such pathogens are responsible for a staggering amount of human sickness and death throughout the world. Leishmaniasis, Chagas disease, toxoplasmosis, and malaria are neglected diseases and therefore are linked to socio-economical and geographical factors, affecting well-over half the world's population. Such obligate intracellular parasites have co-evolved with humans to establish a complexity of specific molecular parasite-host cell interactions, forming the basis of the parasite's cellular tropism. They make use of such interactions to invade host cells as a means to migrate through various tissues, to evade the host immune system, and to undergo intracellular replication. These cellular migration and invasion events are absolutely essential for the completion of the lifecycles of these parasites and lead to their for disease pathogenesis. This review is an overview of the molecular mechanisms of protozoan parasite invasion of host cells and discussion of therapeutic strategies, which could be developed by targeting these invasion pathways. Specifically, we focus on four species of protozoan parasites Leishmania, Trypanosoma cruzi, Plasmodium, and Toxoplasma, which are responsible for significant morbidity and mortality.

  13. Closed cellular materials for smart materials

    NASA Astrophysics Data System (ADS)

    Kishimoto, Satoshi

    2008-11-01

    New methods to fabricate a metallic closed cellular material for smart materials using an isostatic pressing, spark plasma sintering (SPS) method and penetrating method are introduced. Powder particles of polymer or ceramics coated with a metal layer using electro-less plating were pressed into pellets and sintered at high temperatures by sintering at high temperature. Also these powder particles were sintered by spark plasma sintering (SPS) method. Also a many kinds of closed cellular materials with different materials of cell walls and different materials inside of the cell were tried to fabricate. The physical, mechanical and thermal properties of this material were measured. The results of the compressive tests show that this material has the different stress-strain curves among the specimens that have different thickness of the cell walls and the sintering temperatures of the specimens affect the compressive strength of each specimen. Also, the results of the compressive tests show that this material has high-energy absorption and Young's modulus of this material depends on the thickness of the cell walls and sintering conditions. The internal friction of this material was measured and the results show that this internal friction is same as that of pure aluminum.

  14. The cellular slime mold: eukaryotic model microorganism.

    PubMed

    Urushihara, Hideko

    2009-04-01

    Cellular slime molds are eukaryotic microorganisms in the soil. They feed on bacteria as solitary amoebae but conditionally construct multicellular forms in which cell differentiation takes place. Therefore, they are attractive for the study of fundamental biological phenomena such as phagocytosis, cell division, chemotactic movements, intercellular communication, cell differentiation, and morphogenesis. The most widely used species, Dictyostelium discoideum, is highly amenable to experimental manipulation and can be used with most recent molecular biological techniques. Its genome and cDNA analyses have been completed and well-annotated data are publicly available. A larger number of orthologues of human disease-related genes were found in D. discoideum than in yeast. Moreover, some pathogenic bacteria infect Dictyostelium amoebae. Thus, this microorganism can also offer a good experimental system for biomedical research. The resources of cellular slime molds, standard strains, mutants, and genes are maintained and distributed upon request by the core center of the National BioResource Project (NBRP-nenkin) to support Dictyostelium community users as well as new users interested in new platforms for research and/or phylogenic consideration.

  15. Optogenetic control of cellular forces and mechanotransduction.

    PubMed

    Valon, Léo; Marín-Llauradó, Ariadna; Wyatt, Thomas; Charras, Guillaume; Trepat, Xavier

    2017-02-10

    Contractile forces are the end effectors of cell migration, division, morphogenesis, wound healing and cancer invasion. Here we report optogenetic tools to upregulate and downregulate such forces with high spatiotemporal accuracy. The technology relies on controlling the subcellular activation of RhoA using the CRY2/CIBN light-gated dimerizer system. We fused the catalytic domain (DHPH domain) of the RhoA activator ARHGEF11 to CRY2-mCherry (optoGEF-RhoA) and engineered its binding partner CIBN to bind either to the plasma membrane or to the mitochondrial membrane. Translocation of optoGEF-RhoA to the plasma membrane causes a rapid and local increase in cellular traction, intercellular tension and tissue compaction. By contrast, translocation of optoGEF-RhoA to mitochondria results in opposite changes in these physical properties. Cellular changes in contractility are paralleled by modifications in the nuclear localization of the transcriptional regulator YAP, thus showing the ability of our approach to control mechanotransductory signalling pathways in time and space.

  16. Sialidases as regulators of bioengineered cellular surfaces.

    PubMed

    Zamora, Cristina Y; Ryan, Matthew J; d'Alarcao, Marc; Kumar, Krishna

    2015-07-01

    Human sialidases (NEUs) catalyze the removal of N-acetyl neuraminic acids from the glycome of the cell and regulate a diverse repertoire of nominal cellular functions, such as cell signaling and adhesion. A greater understanding of their substrate permissivity is of interest in order to discern their physiological functions in disease states and in the design of specific and effective small molecule inhibitors. Towards this, we have synthesized soluble fluorogenic reporters of mammalian sialidase activity bearing unnatural sialic acids commonly incorporated into the cellular glycocalyx via metabolic glycoengineering. We found cell-surface sialidases in Jurkat capable of cleaving unnatural sialic acids with differential activities toward a variety of R groups on neuraminic acid. In addition, we observed modulated structure-activity relationships when cell-surface sialidases were presented glycans with unnatural bulky, hydrophobic or fluorinated moieties incorporated directly via glycoengineering. Our results confirm the importance of cell-surface sialidases in glycoengineering incorporation data. We demonstrate the flexibility of human NEUs toward derivatized sugars and highlight the importance of native glycan presentation to sialidase binding and activity. These results stand to inform not only metabolic glycoengineering efforts but also inhibitor design.

  17. Sialidases as regulators of bioengineered cellular surfaces

    PubMed Central

    Zamora, Cristina Y; Ryan, Matthew J; d'Alarcao, Marc; Kumar, Krishna

    2015-01-01

    Human sialidases (NEUs) catalyze the removal of N-acetyl neuraminic acids from the glycome of the cell and regulate a diverse repertoire of nominal cellular functions, such as cell signaling and adhesion. A greater understanding of their substrate permissivity is of interest in order to discern their physiological functions in disease states and in the design of specific and effective small molecule inhibitors. Towards this, we have synthesized soluble fluorogenic reporters of mammalian sialidase activity bearing unnatural sialic acids commonly incorporated into the cellular glycocalyx via metabolic glycoengineering. We found cell-surface sialidases in Jurkat capable of cleaving unnatural sialic acids with differential activities toward a variety of R groups on neuraminic acid. In addition, we observed modulated structure–activity relationships when cell-surface sialidases were presented glycans with unnatural bulky, hydrophobic or fluorinated moieties incorporated directly via glycoengineering. Our results confirm the importance of cell-surface sialidases in glycoengineering incorporation data. We demonstrate the flexibility of human NEUs toward derivatized sugars and highlight the importance of native glycan presentation to sialidase binding and activity. These results stand to inform not only metabolic glycoengineering efforts but also inhibitor design. PMID:25795684

  18. Characteristics of cellular composition of periodontal pockets

    PubMed Central

    Hasiuk, Petro; Hasiuk, Nataliya; Kindiy, Dmytro; Ivanchyshyn, Victoriya; Kalashnikov, Dmytro; Zubchenko, Sergiy

    2016-01-01

    Purpose The development of inflammatory periodontal disease in young people is an urgent problem of today's periodontology, and requires a development of new methods that would give an opportunity not only to diagnose but also for prognosis of periodontitis course in a given patients contingent. Results Cellular structure of periodontal pockets is presented by hematogenous and epithelial cells. Our results are confirmed by previous studies, and show that the penetration of periodontal pathogens leads to formation in periodontal tissue of a highly active complex compounds—cytokines that are able to modify the activity of neutrophils and reduce their specific antibacterial properties. Cytokines not only adversely affect the periodontal tissues, but also cause further activation of cells that synthesized them, and inhibit tissue repair and process of resynthesis of connective tissue by fibroblasts. Conclusion Neutrophilic granulocytes present in each of the types of smear types, but their functional status and quantitative composition is different. The results of our cytological study confirmed the results of immunohistochemical studies, and show that in generalized periodontitis, an inflammatory cellular elements with disorganized epithelial cells and connective tissue of the gums and periodontium, and bacteria form specific types of infiltration in periodontal tissues. PMID:28180007

  19. [Cellular phones and cancer: current status].

    PubMed

    Colonna, Anne

    2005-07-01

    Evaluation of the impact of new technologies on the human body is essential in order to impose regulations to limit health risks. The appearance and evolution of cellular phones have been one of the fastest in the history of innovation. Research reported worldwide has tried to evaluate any potential link between adverse health effects and the mobile phone and its broadcasting stations. This article gives an overview of current research knowledge on the impact of radiofrequency waves on health. Epidemiologic, cellular and animal studies have been carried out, but none of them have reached definitive conclusions. Although some biological effects on cell culture have been observed, their link with human cancer development is far from established. Most of the animal studies show negative results. Epidemiologic studies lack a sufficient perspective to be able to evaluate the effect of evolving technologies used today. High levels of concern by the public have urged mobile phone operators, manufacturers and governmental authorities to finance a number of scientific projects aimed at defining adapted and effective regulations.

  20. Piezoelectricity and ferroelectricity of cellular polypropylene electrets films characterized by piezoresponse force microscopy

    SciTech Connect

    Miao, Hongchen; Sun, Yao; Zhou, Xilong; Li, Yingwei; Li, Faxin

    2014-08-14

    Cellular electrets polymer is a new ferroelectret material exhibiting large piezoelectricity and has attracted considerable attentions in researches and industries. Property characterization is very important for this material and current investigations are mostly on macroscopic properties. In this work, we conduct nanoscale piezoelectric and ferroelectric characterizations of cellular polypropylene (PP) films using piezoresponse force microscopy (PFM). First, both the single-frequency PFM and dual-frequency resonance-tracking PFM testings were conducted on the cellular PP film. The localized piezoelectric constant d{sub 33} is estimated to be 7–11pC/N by correcting the resonance magnification with quality factor and it is about one order lower than the macroscopic value. Next, using the switching spectroscopy PFM (SS-PFM), we studied polarization switching behavior of the cellular PP films. Results show that it exhibits the typical ferroelectric-like phase hysteresis loops and butterfly-shaped amplitude loops, which is similar to that of a poly(vinylidene fluoride) (PVDF) ferroelectric polymer film. However, both the phase and amplitude loops of the PP film are intensively asymmetric, which is thought to be caused by the nonzero remnant polarization after poling. Then, the D-E hysteresis loops of both the cellular PP film and PVDF film were measured by using the same wave form as that used in the SS-PFM, and the results show significant differences. Finally, we suggest that the ferroelectric-like behavior of cellular electrets films should be distinguished from that of typical ferroelectrics, both macroscopically and microscopically.