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Fluorescence correlation spectroscopy diffusion laws to probe the submicron cell membrane organization.

PubMed

Wawrezinieck, Laure; Rigneault, Hervé; Marguet, Didier; Lenne, Pierre-François

2005-12-01

To probe the complexity of the cell membrane organization and dynamics, it is important to obtain simple physical observables from experiments on live cells. Here we show that fluorescence correlation spectroscopy (FCS) measurements at different spatial scales enable distinguishing between different submicron confinement models. By plotting the diffusion time versus the transverse area of the confocal volume, we introduce the so-called FCS diffusion law, which is the key concept throughout this article. First, we report experimental FCS diffusion laws for two membrane constituents, which are respectively a putative raft marker and a cytoskeleton-hindered transmembrane protein. We find that these two constituents exhibit very distinct behaviors. To understand these results, we propose different models, which account for the diffusion of molecules either in a membrane comprising isolated microdomains or in a meshwork. By simulating FCS experiments for these two types of organization, we obtain FCS diffusion laws in agreement with our experimental observations. We also demonstrate that simple observables derived from these FCS diffusion laws are strongly related to confinement parameters such as the partition of molecules in microdomains and the average confinement time of molecules in a microdomain or a single mesh of a meshwork.
Spatiotemporal mapping of diffusion dynamics and organization in plasma membranes

NASA Astrophysics Data System (ADS)

Bag, Nirmalya; Ng, Xue Wen; Sankaran, Jagadish; Wohland, Thorsten

2016-09-01

Imaging fluorescence correlation spectroscopy (FCS) and the related FCS diffusion law have been applied in recent years to investigate the diffusion modes of lipids and proteins in membranes. These efforts have provided new insights into the membrane structure below the optical diffraction limit, new information on the existence of lipid domains, and on the influence of the cytoskeleton on membrane dynamics. However, there has been no systematic study to evaluate how domain size, domain density, and the probe partition coefficient affect the resulting imaging FCS diffusion law parameters. Here, we characterize the effects of these factors on the FCS diffusion law through simulations and experiments on lipid bilayers and live cells. By segmenting images into smaller 7 × 7 pixel areas, we can evaluate the FCS diffusion law on areas smaller than 2 µm and thus provide detailed maps of information on the membrane structure and heterogeneity at this length scale. We support and extend this analysis by deriving a mathematical expression to calculate the mean squared displacement (MSDACF) from the autocorrelation function of imaging FCS, and demonstrate that the MSDACF plots depend on the existence of nanoscopic domains. Based on the results, we derive limits for the detection of domains depending on their size, density, and relative viscosity in comparison to the surroundings. Finally, we apply these measurements to bilayers and live cells using imaging total internal reflection FCS and single plane illumination microscopy FCS.
FCS diffusion laws in two-phase lipid membranes: determination of domain mean size by experiments and Monte Carlo simulations.

PubMed

Favard, Cyril; Wenger, Jérôme; Lenne, Pierre-François; Rigneault, Hervé

2011-03-02

Many efforts have been undertaken over the last few decades to characterize the diffusion process in model and cellular lipid membranes. One of the techniques developed for this purpose, fluorescence correlation spectroscopy (FCS), has proved to be a very efficient approach, especially if the analysis is extended to measurements on different spatial scales (referred to as FCS diffusion laws). In this work, we examine the relevance of FCS diffusion laws for probing the behavior of a pure lipid and a lipid mixture at temperatures below, within and above the phase transitions, both experimentally and numerically. The accuracy of the microscopic description of the lipid mixtures found here extends previous work to a more complex model in which the geometry is unknown and the molecular motion is driven only by the thermodynamic parameters of the system itself. For multilamellar vesicles of both pure lipid and lipid mixtures, the FCS diffusion laws recorded at different temperatures exhibit large deviations from pure Brownian motion and reveal the existence of nanodomains. The variation of the mean size of these domains with temperature is in perfect correlation with the enthalpy fluctuation. This study highlights the advantages of using FCS diffusion laws in complex lipid systems to describe their temporal and spatial structure. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.
Fluorescence correlation spectroscopy diffusion laws in the presence of moving nanodomains

NASA Astrophysics Data System (ADS)

Šachl, Radek; Bergstrand, Jan; Widengren, Jerker; Hof, Martin

2016-03-01

It has been shown by means of simulations that spot variation fluorescence correlation spectroscopy (sv-FCS) can be used for the identification and, to some extent, also characterization of immobile lipid nanodomains in model as well as cellular plasma membranes. However, in these simulations, the nanodomains were assumed to be stationary, whereas they actually tend to move like the surrounding lipids. In the present study, we investigated how such domain movement influences the diffusion time/spot-size dependence observed in FCS experiments, usually referred to as ‘diffusion law’ analysis. We show that domain movement might mask the effects of the ‘anomalous’ diffusion characteristics of membrane lipids or proteins predicted for stationary domains, making it difficult to identify such moving nanodomains by sv-FCS. More specifically, our simulations indicate that (i) for domains moving up to a factor of 2.25 slower than the surrounding lipids, such impeded diffusion cannot be observed and the diffusion behaviour of the proteins or lipids is indistinguishable from that of freely diffusing molecules, i.e. nanodomains are not detected; (ii) impeded protein/lipid diffusion behaviour can be observed in experiments where the radii of the detection volume are similar in size to the domain radii, the domain diffusion is about 10 times slower than that of the lipids, and the probes show a high affinity to the domains; and (iii) presence of nanodomains can only be reliably detected by diffraction limited sv-FCS when the domains move very slowly (about 200 times slower than the lipid diffusion). As nanodomains are expected to be in the range of tens of nanometres and most probes show low affinities to such domains, sv-FCS is limited to stationary domains and/or STED-FCS. However, even for that latter technique, diffusing domains smaller than 50 nm in radius are hardly detectable by FCS diffusion time/spot-size dependencies.
Nanoscale Spatiotemporal Diffusion Modes Measured by Simultaneous Confocal and Stimulated Emission Depletion Nanoscopy Imaging.

PubMed

Schneider, Falk; Waithe, Dominic; Galiani, Silvia; Bernardino de la Serna, Jorge; Sezgin, Erdinc; Eggeling, Christian

2018-06-19

The diffusion dynamics in the cellular plasma membrane provide crucial insights into molecular interactions, organization, and bioactivity. Beam-scanning fluorescence correlation spectroscopy combined with super-resolution stimulated emission depletion nanoscopy (scanning STED-FCS) measures such dynamics with high spatial and temporal resolution. It reveals nanoscale diffusion characteristics by measuring the molecular diffusion in conventional confocal mode and super-resolved STED mode sequentially for each pixel along the scanned line. However, to directly link the spatial and the temporal information, a method that simultaneously measures the diffusion in confocal and STED modes is needed. Here, to overcome this problem, we establish an advanced STED-FCS measurement method, line interleaved excitation scanning STED-FCS (LIESS-FCS), that discloses the molecular diffusion modes at different spatial positions with a single measurement. It relies on fast beam-scanning along a line with alternating laser illumination that yields, for each pixel, the apparent diffusion coefficients for two different observation spot sizes (conventional confocal and super-resolved STED). We demonstrate the potential of the LIESS-FCS approach with simulations and experiments on lipid diffusion in model and live cell plasma membranes. We also apply LIESS-FCS to investigate the spatiotemporal organization of glycosylphosphatidylinositol-anchored proteins in the plasma membrane of live cells, which, interestingly, show multiple diffusion modes at different spatial positions.
Measurement of nanoscale three-dimensional diffusion in the interior of living cells by STED-FCS.

PubMed

Lanzanò, Luca; Scipioni, Lorenzo; Di Bona, Melody; Bianchini, Paolo; Bizzarri, Ranieri; Cardarelli, Francesco; Diaspro, Alberto; Vicidomini, Giuseppe

2017-07-06

The observation of molecular diffusion at different spatial scales, and in particular below the optical diffraction limit (<200 nm), can reveal details of the subcellular topology and its functional organization. Stimulated-emission depletion microscopy (STED) has been previously combined with fluorescence correlation spectroscopy (FCS) to investigate nanoscale diffusion (STED-FCS). However, stimulated-emission depletion fluorescence correlation spectroscopy has only been used successfully to reveal functional organization in two-dimensional space, such as the plasma membrane, while, an efficient implementation for measurements in three-dimensional space, such as the cellular interior, is still lacking. Here we integrate the STED-FCS method with two analytical approaches, the recent separation of photons by lifetime tuning and the fluorescence lifetime correlation spectroscopy, to simultaneously probe diffusion in three dimensions at different sub-diffraction scales. We demonstrate that this method efficiently provides measurement of the diffusion of EGFP at spatial scales tunable from the diffraction size down to ∼80 nm in the cytoplasm of living cells.The measurement of molecular diffusion at sub-diffraction scales has been achieved in 2D space using STED-FCS, but an implementation for 3D diffusion is lacking. Here the authors present an analytical approach to probe diffusion in 3D space using STED-FCS and measure the diffusion of EGFP at different spatial scales.
Plasma membrane organization and dynamics is probe and cell line dependent.

PubMed

Huang, Shuangru; Lim, Shi Ying; Gupta, Anjali; Bag, Nirmalya; Wohland, Thorsten

2017-09-01

The action and interaction of membrane receptor proteins take place within the plasma membrane. The plasma membrane, however, is not a passive matrix. It rather takes an active role and regulates receptor distribution and function by its composition and the interaction of its lipid components with embedded and surrounding proteins. Furthermore, it is not a homogenous fluid but contains lipid and protein domains of various sizes and characteristic lifetimes which are important in regulating receptor function and signaling. The precise lateral organization of the plasma membrane, the differences between the inner and outer leaflet, and the influence of the cytoskeleton are still debated. Furthermore, there is a lack of comparisons of the organization and dynamics of the plasma membrane of different cell types. Therefore, we used four different specific membrane markers to test the lateral organization, the differences between the inner and outer membrane leaflet, and the influence of the cytoskeleton of up to five different cell lines, including Chinese hamster ovary (CHO-K1), Human cervical carcinoma (HeLa), neuroblastoma (SH-SY5Y), fibroblast (WI-38) and rat basophilic leukemia (RBL-2H3) cells by Imaging Total Internal Reflection (ITIR)-Fluorescence Correlation Spectroscopy (FCS). We measure diffusion in the temperature range of 298-310K to measure the Arrhenius activation energy (E Arr ) of diffusion and apply the FCS diffusion law to obtain information on the spatial organization of the probe molecules on the various cell membranes. Our results show clear differences of the FCS diffusion law and E Arr for the different probes in dependence of their localization. These differences are similar in the outer and inner leaflet of the membrane. However, these values can differ significantly between different cell lines raising the question how molecular plasma membrane events measured in different cell lines can be compared. This article is part of a Special Issue entitled: Interactions between membrane receptors in cellular membranes edited by Kalina Hristova. Copyright © 2016 Elsevier B.V. All rights reserved.
Probing GFP-actin diffusion in living cells using fluorescence correlation spectroscopy.

PubMed

Engelke, Hanna; Heinrich, Doris; Rädler, Joachim O

2010-12-22

The cytoskeleton of eukaryotic cells is continuously remodeled by polymerization and depolymerization of actin. Consequently, the relative content of polymerized filamentous actin (F-actin) and monomeric globular actin (G-actin) is subject to temporal and spatial fluctuations. Since fluorescence correlation spectroscopy (FCS) can measure the diffusion of fluorescently labeled actin it seems likely that FCS allows us to determine the dynamics and hence indirectly the structural properties of the cytoskeleton components with high spatial resolution. To this end we investigate the FCS signal of GFP-actin in living Dictyostelium discoideum cells and explore the inherent spatial and temporal signatures of the actin cytoskeleton. Using the free green fluorescent protein (GFP) as a reference, we find that actin diffusion inside cells is dominated by G-actin and slower than diffusion in diluted cell extract. The FCS signal in the dense cortical F-actin network near the cell membrane is probed using the cytoskeleton protein LIM and is found to be slower than cytosolic G-actin diffusion. Furthermore, we show that polymerization of the cytoskeleton induced by Jasplakinolide leads to a substantial decrease of G-actin diffusion. Pronounced fluctuations in the distribution of the FCS correlation curves can be induced by latrunculin, which is known to induce actin waves. Our work suggests that the FCS signal of GFP-actin in combination with scanning or spatial correlation techniques yield valuable information about the local dynamics and concomitant cytoskeletal properties.
On the Equivalence of FCS and FRAP: Simultaneous Lipid Membrane Measurements.

PubMed

Macháň, Radek; Foo, Yong Hwee; Wohland, Thorsten

2016-07-12

Fluorescence correlation spectroscopy (FCS) and fluorescence recovery after photobleaching (FRAP) are widely used methods to determine diffusion coefficients. However, they often do not yield the same results. With the advent of camera-based imaging FCS, which measures the diffusion coefficient in each pixel of an image, and proper bleaching corrections, it is now possible to measure the diffusion coefficient by FRAP and FCS in the exact same images. We thus performed simultaneous FCS and FRAP measurements on supported lipid bilayers and live cell membranes to test how far the two methods differ in their results and whether the methodological differences, in particular the high bleach intensity in FRAP, the bleach corrections, and the fitting procedures in the two methods explain observed differences. Overall, we find that the FRAP bleach intensity does not measurably influence the diffusion in the samples, but that bleach correction and fitting introduce large uncertainties in FRAP. We confirm our results by simulations. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.
Communication: Development of standing evanescent-wave fluorescence correlation spectroscopy and its application to the lateral diffusion of lipids in a supported lipid bilayer

NASA Astrophysics Data System (ADS)

Otosu, Takuhiro; Yamaguchi, Shoichi

2017-07-01

We present standing evanescent-wave fluorescence correlation spectroscopy (SEW-FCS). This technique utilizes the interference of two evanescent waves which generates a standing evanescent-wave. Fringe-pattern illumination created by a standing evanescent-wave enables us to measure the diffusion coefficients of molecules with a super-resolution corresponding to one fringe width. Because the fringe width can be reliably estimated by a simple procedure, utilization of fringes is beneficial to quantitatively analyze the slow diffusion of molecules in a supported lipid bilayer (SLB), a model biomembrane formed on a solid substrate, with the timescale relevant for reliable FCS analysis. Furthermore, comparison of the data between SEW-FCS and conventional total-internal reflection FCS, which can also be performed by the SEW-FCS instrument, effectively eliminates the artifact due to afterpulsing of the photodiode detector. The versatility of SEW-FCS is demonstrated by its application to various SLBs.
Recent Developments in Fluorescence Correlation Spectroscopy for Diffusion Measurements in Planar Lipid Membranes

PubMed Central

Macháň, Radek; Hof, Martin

2010-01-01

Fluorescence correlation spectroscopy (FCS) is a single molecule technique used mainly for determination of mobility and local concentration of molecules. This review describes the specific problems of FCS in planar systems and reviews the state of the art experimental approaches such as 2-focus, Z-scan or scanning FCS, which overcome most of the artefacts and limitations of standard FCS. We focus on diffusion measurements of lipids and proteins in planar lipid membranes and review the contributions of FCS to elucidating membrane dynamics and the factors influencing it, such as membrane composition, ionic strength, presence of membrane proteins or frictional coupling with solid support. PMID:20386647
Multiplexed measurement of protein diffusion in Caenorhabditis elegans embryos with SPIM-FCS

NASA Astrophysics Data System (ADS)

Struntz, Philipp; Weiss, Matthias

2016-02-01

Quantifying the diffusion behavior of proteins in different environments, e.g. on cellular membranes, is a key step in uncovering the vital action of protein networks in living organisms. While several established techniques for local diffusion measurements exist, the life sciences are currently in need of a multiplexed, i.e. spatially parallelized, data acquisition that allows for obtaining diffusion maps with high spatiotemporal resolution. Following this demand, the combination of camera-based single-plane illumination microscopy (SPIM) and fluorescence correlation spectroscopy (FCS) has recently emerged as a promising approach. So far, SPIM-FCS has mainly been used to assess the diffusion of soluble particles and proteins in vitro and in culture cells, but due to a particularly low photobleaching and -toxicity the method is also well applicable to developmental organisms. Here, we have probed the performance of SPIM-FCS on an established developmental model organism, the small nematode Caenorhabditis elegans. In particular, we have quantified the diffusion of the peripheral membrane protein PLC1δ 1 in the embryo’s cytoplasm and on the plasma membrane. As a result, we were able to derive diffusion maps of PLC1δ 1 in both compartments in multiple individuals, showing the spatially varying diffusion coefficients across the embryo. Our data also report on the dissociation kinetics of PLC1δ 1 from the plasma membrane, hence underlining that SPIM-FCS can be used to explore key features of peripheral membrane proteins in fragile developmental model organisms.
A straightforward approach for gated STED-FCS to investigate lipid membrane dynamics

PubMed Central

Clausen, Mathias P.; Sezgin, Erdinc; Bernardino de la Serna, Jorge; Waithe, Dominic; Lagerholm, B. Christoffer; Eggeling, Christian

2015-01-01

Recent years have seen the development of multiple technologies to investigate, with great spatial and temporal resolution, the dynamics of lipids in cellular and model membranes. One of these approaches is the combination of far-field super-resolution stimulated-emission-depletion (STED) microscopy with fluorescence correlation spectroscopy (FCS). STED-FCS combines the diffraction-unlimited spatial resolution of STED microscopy with the statistical accuracy of FCS to determine sub-millisecond-fast molecular dynamics with single-molecule sensitivity. A unique advantage of STED-FCS is that the observation spot for the FCS data recordings can be tuned to sub-diffraction scales, i.e. <200 nm in diameter, in a gradual manner to investigate fast diffusion of membrane-incorporated labelled entities. Unfortunately, so far the STED-FCS technology has mostly been applied on a few custom-built setups optimised for far-red fluorescent emitters. Here, we summarise the basics of the STED-FCS technology and highlight how it can give novel details into molecular diffusion modes. Most importantly, we present a straightforward way for performing STED-FCS measurements on an unmodified turnkey commercial system using a time-gated detection scheme. Further, we have evaluated the STED-FCS performance of different commonly used green emitting fluorescent dyes applying freely available, custom-written analysis software. PMID:26123184
Inferring Diffusion Dynamics from FCS in Heterogeneous Nuclear Environments

PubMed Central

Tsekouras, Konstantinos; Siegel, Amanda P.; Day, Richard N.; Pressé, Steve

2015-01-01

Fluorescence correlation spectroscopy (FCS) is a noninvasive technique that probes the diffusion dynamics of proteins down to single-molecule sensitivity in living cells. Critical mechanistic insight is often drawn from FCS experiments by fitting the resulting time-intensity correlation function, G(t), to known diffusion models. When simple models fail, the complex diffusion dynamics of proteins within heterogeneous cellular environments can be fit to anomalous diffusion models with adjustable anomalous exponents. Here, we take a different approach. We use the maximum entropy method to show—first using synthetic data—that a model for proteins diffusing while stochastically binding/unbinding to various affinity sites in living cells gives rise to a G(t) that could otherwise be equally well fit using anomalous diffusion models. We explain the mechanistic insight derived from our method. In particular, using real FCS data, we describe how the effects of cell crowding and binding to affinity sites manifest themselves in the behavior of G(t). Our focus is on the diffusive behavior of an engineered protein in 1) the heterochromatin region of the cell’s nucleus as well as 2) in the cell’s cytoplasm and 3) in solution. The protein consists of the basic region-leucine zipper (BZip) domain of the CCAAT/enhancer-binding protein (C/EBP) fused to fluorescent proteins. PMID:26153697
The Effect of a Fluorophore Photo-Physics on the Lipid Vesicle Diffusion Coefficient Studied by Fluorescence Correlation Spectroscopy.

PubMed

Drabik, Dominik; Przybyło, Magda; Sikorski, Aleksander; Langner, Marek

2016-03-01

Fluorescence Correlation Spectroscopy (FCS) is a technique, which allows determination of the diffusion coefficient and concentration of fluorescent objects suspended in the solution. The measured parameter is the fluctuation of the fluorescence signal emitted by diffusing molecules. When 100 nm DOPC vesicles labeled with various fluorescent dyes (Fluorescein-PE, NBD-PE, Atto488 DOPE or βBodipy FL) were measured, different values of diffusion coefficients have been obtained. These diffusion coefficients were different from the expected values measured using the dynamic light scattering method (DLS). The FCS was initially developed for solutions containing small fluorescent molecules therefore the observed inconsistency may result from the nature of vesicle suspension itself. The duration of the fluorescence signal may depend on the following factors: the exposure time of the labeled object to the excitation beam, the photo-physical properties (e.g., stability) of a fluorophore, the theoretical model used for the calculations of the diffusion coefficient and optical properties of the vesicle suspension. The diffusion coefficients determined for differently labeled liposomes show that its dependence on vesicle size and quantity of fluorescent probed used for labeling was significant demonstrating that the fluorescence properties of the fluorophore itself (bleaching and/or blinking) were critical factors for a correct outcome of FCS experiment. The new, based on combined FCS and DLS measurements, method for the determination of the focal volume prove itself to be useful for the evaluation of a fluorescence dye with respect to its applicability for FCS experiment.
Inferring diffusion dynamics from FCS in heterogeneous nuclear environments.

PubMed

Tsekouras, Konstantinos; Siegel, Amanda P; Day, Richard N; Pressé, Steve

2015-07-07

Fluorescence correlation spectroscopy (FCS) is a noninvasive technique that probes the diffusion dynamics of proteins down to single-molecule sensitivity in living cells. Critical mechanistic insight is often drawn from FCS experiments by fitting the resulting time-intensity correlation function, G(t), to known diffusion models. When simple models fail, the complex diffusion dynamics of proteins within heterogeneous cellular environments can be fit to anomalous diffusion models with adjustable anomalous exponents. Here, we take a different approach. We use the maximum entropy method to show-first using synthetic data-that a model for proteins diffusing while stochastically binding/unbinding to various affinity sites in living cells gives rise to a G(t) that could otherwise be equally well fit using anomalous diffusion models. We explain the mechanistic insight derived from our method. In particular, using real FCS data, we describe how the effects of cell crowding and binding to affinity sites manifest themselves in the behavior of G(t). Our focus is on the diffusive behavior of an engineered protein in 1) the heterochromatin region of the cell's nucleus as well as 2) in the cell's cytoplasm and 3) in solution. The protein consists of the basic region-leucine zipper (BZip) domain of the CCAAT/enhancer-binding protein (C/EBP) fused to fluorescent proteins. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.
Convergence of lateral dynamic measurements in the plasma membrane of live cells from single particle tracking and STED-FCS

NASA Astrophysics Data System (ADS)

Lagerholm, B. Christoffer; Andrade, Débora M.; Clausen, Mathias P.; Eggeling, Christian

2017-02-01

Fluorescence correlation spectroscopy (FCS) in combination with the super-resolution imaging method STED (STED-FCS), and single-particle tracking (SPT) are able to directly probe the lateral dynamics of lipids and proteins in the plasma membrane of live cells at spatial scales much below the diffraction limit of conventional microscopy. However, a major disparity in interpretation of data from SPT and STED-FCS remains, namely the proposed existence of a very fast (unhindered) lateral diffusion coefficient, ⩾5 µm2 s-1, in the plasma membrane of live cells at very short length scales, ≈⩽ 100 nm, and time scales, ≈1-10 ms. This fast diffusion coefficient has been advocated in several high-speed SPT studies, for lipids and membrane proteins alike, but the equivalent has not been detected in STED-FCS measurements. Resolving this ambiguity is important because the assessment of membrane dynamics currently relies heavily on SPT for the determination of heterogeneous diffusion. A possible systematic error in this approach would thus have vast implications in this field. To address this, we have re-visited the analysis procedure for SPT data with an emphasis on the measurement errors and the effect that these errors have on the measurement outputs. We subsequently demonstrate that STED-FCS and SPT data, following careful consideration of the experimental errors of the SPT data, converge to a common interpretation which for the case of a diffusing phospholipid analogue in the plasma membrane of live mouse embryo fibroblasts results in an unhindered, intra-compartment, diffusion coefficient of ≈0.7-1.0 µm2 s-1, and a compartment size of about 100-150 nm.
Convergence of lateral dynamic measurements in the plasma membrane of live cells from single particle tracking and STED-FCS

PubMed Central

Lagerholm, B Christoffer; Andrade, Débora M; Clausen, Mathias P; Eggeling, Christian

2017-01-01

Abstract Fluorescence correlation spectroscopy (FCS) in combination with the super-resolution imaging method STED (STED-FCS), and single-particle tracking (SPT) are able to directly probe the lateral dynamics of lipids and proteins in the plasma membrane of live cells at spatial scales much below the diffraction limit of conventional microscopy. However, a major disparity in interpretation of data from SPT and STED-FCS remains, namely the proposed existence of a very fast (unhindered) lateral diffusion coefficient, ⩾5 µm2 s−1, in the plasma membrane of live cells at very short length scales, ≈⩽ 100 nm, and time scales, ≈1–10 ms. This fast diffusion coefficient has been advocated in several high-speed SPT studies, for lipids and membrane proteins alike, but the equivalent has not been detected in STED-FCS measurements. Resolving this ambiguity is important because the assessment of membrane dynamics currently relies heavily on SPT for the determination of heterogeneous diffusion. A possible systematic error in this approach would thus have vast implications in this field. To address this, we have re-visited the analysis procedure for SPT data with an emphasis on the measurement errors and the effect that these errors have on the measurement outputs. We subsequently demonstrate that STED-FCS and SPT data, following careful consideration of the experimental errors of the SPT data, converge to a common interpretation which for the case of a diffusing phospholipid analogue in the plasma membrane of live mouse embryo fibroblasts results in an unhindered, intra-compartment, diffusion coefficient of ≈0.7–1.0 µm2 s−1, and a compartment size of about 100–150 nm. PMID:28458397
Molecular Diffusion in Plasma Membranes of Primary Lymphocytes Measured by Fluorescence Correlation Spectroscopy.

PubMed

Staaf, Elina; Bagawath-Singh, Sunitha; Johansson, Sofia

2017-02-01

Fluorescence correlation spectroscopy (FCS) is a powerful technique for studying the diffusion of molecules within biological membranes with high spatial and temporal resolution. FCS can quantify the molecular concentration and diffusion coefficient of fluorescently labeled molecules in the cell membrane. This technique has the ability to explore the molecular diffusion characteristics of molecules in the plasma membrane of immune cells in steady state (i.e., without processes affecting the result during the actual measurement time). FCS is suitable for studying the diffusion of proteins that are expressed at levels typical for most endogenous proteins. Here, a straightforward and robust method to determine the diffusion rate of cell membrane proteins on primary lymphocytes is demonstrated. An effective way to perform measurements on antibody-stained live cells and commonly occurring observations after acquisition are described. The recent advancements in the development of photo-stable fluorescent dyes can be utilized by conjugating the antibodies of interest to appropriate dyes that do not bleach extensively during the measurements. Additionally, this allows for the detection of slowly diffusing entities, which is a common feature of proteins expressed in cell membranes. The analysis procedure to extract molecular concentration and diffusion parameters from the generated autocorrelation curves is highlighted. In summary, a basic protocol for FCS measurements is provided; it can be followed by immunologists with an understanding of confocal microscopy but with no other previous experience of techniques for measuring dynamic parameters, such as molecular diffusion rates.
λ-Repressor Oligomerization Kinetics at High Concentrations Using Fluorescence Correlation Spectroscopy in Zero-Mode Waveguides

PubMed Central

Samiee, K. T.; Foquet, M.; Guo, L.; Cox, E. C.; Craighead, H. G.

2005-01-01

Fluorescence correlation spectroscopy (FCS) has demonstrated its utility for measuring transport properties and kinetics at low fluorophore concentrations. In this article, we demonstrate that simple optical nanostructures, known as zero-mode waveguides, can be used to significantly reduce the FCS observation volume. This, in turn, allows FCS to be applied to solutions with significantly higher fluorophore concentrations. We derive an empirical FCS model accounting for one-dimensional diffusion in a finite tube with a simple exponential observation profile. This technique is used to measure the oligomerization of the bacteriophage λ repressor protein at micromolar concentrations. The results agree with previous studies utilizing conventional techniques. Additionally, we demonstrate that the zero-mode waveguides can be used to assay biological activity by measuring changes in diffusion constant as a result of ligand binding. PMID:15613638

Messages Do Diffuse Faster than Messengers: Reconciling Disparate Estimates of the Morphogen Bicoid Diffusion Coefficient

PubMed Central

Sigaut, Lorena; Pearson, John E.; Colman-Lerner, Alejandro; Ponce Dawson, Silvina

2014-01-01

The gradient of Bicoid (Bcd) is key for the establishment of the anterior-posterior axis in Drosophila embryos. The gradient properties are compatible with the SDD model in which Bcd is synthesized at the anterior pole and then diffuses into the embryo and is degraded with a characteristic time. Within this model, the Bcd diffusion coefficient is critical to set the timescale of gradient formation. This coefficient has been measured using two optical techniques, Fluorescence Recovery After Photobleaching (FRAP) and Fluorescence Correlation Spectroscopy (FCS), obtaining estimates in which the FCS value is an order of magnitude larger than the FRAP one. This discrepancy raises the following questions: which estimate is "correct''; what is the reason for the disparity; and can the SDD model explain Bcd gradient formation within the experimentally observed times? In this paper, we use a simple biophysical model in which Bcd diffuses and interacts with binding sites to show that both the FRAP and the FCS estimates may be correct and compatible with the observed timescale of gradient formation. The discrepancy arises from the fact that FCS and FRAP report on different effective (concentration dependent) diffusion coefficients, one of which describes the spreading rate of the individual Bcd molecules (the messengers) and the other one that of their concentration (the message). The latter is the one that is more relevant for the gradient establishment and is compatible with its formation within the experimentally observed times. PMID:24901638
Diffusion and binding analyzed with combined point FRAP and FCS.

PubMed

Im, Kang-Bin; Schmidt, Ute; Kang, Moon-Sik; Lee, Ji-Young; Bestvater, Felix; Wachsmuth, Malte

2013-09-01

To quantify more precisely and more reliably diffusion and reaction properties of biomolecules in living cells, a novel closed description in 3D of both the bleach and the post-bleach segment of fluorescence recovery after photobleaching (FRAP) data acquired at a point, i.e., a diffraction-limited observation area, termed point FRAP, is presented. It covers a complete coupled reaction-diffusion scheme for mobile molecules undergoing transient or long-term immobilization because of binding. We assess and confirm the feasibility with numerical solutions of the differential equations. By applying this model to free EYFP expressed in HeLa cells using a customized confocal laser scanning microscope that integrates point FRAP and fluorescence correlation spectroscopy (FCS), the applicability is validated by comparison with results from FCS. We show that by taking diffusion during bleaching into consideration and/or by employing a global analysis of series of bleach times, the results can be improved significantly. As the point FRAP approach allows to obtain data with diffraction-limited positioning accuracy, diffusion and binding properties of the exon-exon junction complex (EJC) components REF2-II and Magoh are obtained at different localizations in the nucleus of MCF7 cells and refine our view on the position-dependent association of the EJC factors with a maturating mRNP complex. Our findings corroborate the concept of combining point FRAP and FCS for a better understanding of the underlying diffusion and binding processes. Copyright © 2013 International Society for Advancement of Cytometry.
Messages do diffuse faster than messengers: reconciling disparate estimates of the morphogen bicoid diffusion coefficient.

PubMed

Sigaut, Lorena; Pearson, John E; Colman-Lerner, Alejandro; Ponce Dawson, Silvina

2014-06-01

The gradient of Bicoid (Bcd) is key for the establishment of the anterior-posterior axis in Drosophila embryos. The gradient properties are compatible with the SDD model in which Bcd is synthesized at the anterior pole and then diffuses into the embryo and is degraded with a characteristic time. Within this model, the Bcd diffusion coefficient is critical to set the timescale of gradient formation. This coefficient has been measured using two optical techniques, Fluorescence Recovery After Photobleaching (FRAP) and Fluorescence Correlation Spectroscopy (FCS), obtaining estimates in which the FCS value is an order of magnitude larger than the FRAP one. This discrepancy raises the following questions: which estimate is "correct''; what is the reason for the disparity; and can the SDD model explain Bcd gradient formation within the experimentally observed times? In this paper, we use a simple biophysical model in which Bcd diffuses and interacts with binding sites to show that both the FRAP and the FCS estimates may be correct and compatible with the observed timescale of gradient formation. The discrepancy arises from the fact that FCS and FRAP report on different effective (concentration dependent) diffusion coefficients, one of which describes the spreading rate of the individual Bcd molecules (the messengers) and the other one that of their concentration (the message). The latter is the one that is more relevant for the gradient establishment and is compatible with its formation within the experimentally observed times.
Lateral Membrane Diffusion Modulated by a Minimal Actin Cortex

PubMed Central

Heinemann, Fabian; Vogel, Sven K.; Schwille, Petra

2013-01-01

Diffusion of lipids and proteins within the cell membrane is essential for numerous membrane-dependent processes including signaling and molecular interactions. It is assumed that the membrane-associated cytoskeleton modulates lateral diffusion. Here, we use a minimal actin cortex to directly study proposed effects of an actin meshwork on the diffusion in a well-defined system. The lateral diffusion of a lipid and a protein probe at varying densities of membrane-bound actin was characterized by fluorescence correlation spectroscopy (FCS). A clear correlation of actin density and reduction in mobility was observed for both the lipid and the protein probe. At high actin densities, the effect on the protein probe was ∼3.5-fold stronger compared to the lipid. Moreover, addition of myosin filaments, which contract the actin mesh, allowed switching between fast and slow diffusion in the minimal system. Spot variation FCS was in accordance with a model of fast microscopic diffusion and slower macroscopic diffusion. Complementing Monte Carlo simulations support the analysis of the experimental FCS data. Our results suggest a stronger interaction of the actin mesh with the larger protein probe compared to the lipid. This might point toward a mechanism where cortical actin controls membrane diffusion in a strong size-dependent manner. PMID:23561523
A New Technique for Measuring Concentration Dependence of Self and Collective Diffusivity by using a Single Sample

NASA Astrophysics Data System (ADS)

Sirorattanakul, Krittanon; Shen, Chong; Ou-Yang, Daniel

Diffusivity governs the dynamics of interacting particles suspended in a solvent. At high particle concentration, the interactions between particles become non-negligible, making the values of self and collective diffusivity diverge and concentration-dependent. Conventional methods for measuring this dependency, such as forced Rayleigh scattering, fluorescence correlation spectroscopy (FCS), and dynamic light scattering (DLS) require preparation of multiple samples. We present a new technique to measure this dependency by using only a single sample. Dielectrophoresis (DEP) is used to create concentration gradient in the solution. Across this concentration distribution, we use FCS to measure the concentration-dependent self diffusivity. Then, we switch off DEP to allow the particles to diffuse back to equilibrium. We obtain the time series of concentration distribution from fluorescence microscopy and use them to determine the concentration-dependent collective diffusivity. We compare the experimental results with computer simulations to verify the validity of this technique. Time and spatial resolution limits of FCS and imaging are also analyzed to estimate the limitation of the proposed technique. NSF DMR-0923299, Lehigh College of Arts and Sciences Undergraduate Research Grant, Lehigh Department of Physics, Emulsion Polymers Institute.
Complementary studies of lipid membrane dynamics using iSCAT and super-resolved fluorescence correlation spectroscopy

NASA Astrophysics Data System (ADS)

Reina, Francesco; Galiani, Silvia; Shrestha, Dilip; Sezgin, Erdinc; de Wit, Gabrielle; Cole, Daniel; Lagerholm, B. Christoffer; Kukura, Philipp; Eggeling, Christian

2018-06-01

Observation techniques with high spatial and temporal resolution, such as single-particle tracking based on interferometric scattering (iSCAT) microscopy, and fluorescence correlation spectroscopy applied on a super-resolution STED microscope (STED-FCS), have revealed new insights of the molecular organization of membranes. While delivering complementary information, there are still distinct differences between these techniques, most prominently the use of fluorescent dye tagged probes for STED-FCS and a need for larger scattering gold nanoparticle tags for iSCAT. In this work, we have used lipid analogues tagged with a hybrid fluorescent tag–gold nanoparticle construct, to directly compare the results from STED-FCS and iSCAT measurements of phospholipid diffusion on a homogeneous supported lipid bilayer (SLB). These comparative measurements showed that while the mode of diffusion remained free, at least at the spatial (>40 nm) and temporal (50 ⩽ t ⩽ 100 ms) scales probed, the diffussion coefficient was reduced by 20- to 60-fold when tagging with 20 and 40 nm large gold particles as compared to when using dye tagged lipid analogues. These FCS measurements of hybrid fluorescent tag–gold nanoparticle labeled lipids also revealed that commercially supplied streptavidin-coated gold nanoparticles contain large quantities of free streptavidin. Finally, the values of apparent diffusion coefficients obtained by STED-FCS and iSCAT differed by a factor of 2–3 across the techniques, while relative differences in mobility between different species of lipid analogues considered were identical in both approaches. In conclusion, our experiments reveal that large and potentially cross-linking scattering tags introduce a significant slow-down in diffusion on SLBs but no additional bias, and our labeling approach creates a new way of exploiting complementary information from STED-FCS and iSCAT measurements.
A total internal reflection-fluorescence correlation spectroscopy setup with pulsed diode laser excitation

NASA Astrophysics Data System (ADS)

Weger, Lukas; Hoffmann-Jacobsen, Kerstin

2017-09-01

Fluorescence correlation spectroscopy (FCS) measures fluctuations in a (sub-)femtoliter volume to analyze the diffusive behavior of fluorescent particles. This highly sensitive method has proven to be useful for the analysis of dynamic biological systems as well as in chemistry, physics, and material sciences. It is routinely performed with commercial fluorescence microscopes, which provide a confined observation volume by the confocal technique. The evanescent wave of total internal reflectance (TIR) is used in home-built systems to permit a surface sensitive FCS analysis. We present a combined confocal and TIR-FCS setup which uses economic low-power pulsed diode lasers for excitation. Excitation and detection are coupled to time-correlated photon counting hardware. This allows simultaneous fluorescence lifetime and FCS measurements in a surface-sensitive mode. Moreover, the setup supports fluorescence lifetime correlation spectroscopy at surfaces. The excitation can be easily switched between TIR and epi-illumination to compare the surface properties with those in liquid bulk. The capabilities of the presented setup are demonstrated by measuring the diffusion coefficients of a free dye molecule, a labeled polyethylene glycol, and a fluorescent nanoparticle in confocal as well as in TIR-FCS.
Measuring and imaging diffusion with multiple scan speed image correlation spectroscopy.

PubMed

Gröner, Nadine; Capoulade, Jérémie; Cremer, Christoph; Wachsmuth, Malte

2010-09-27

The intracellular mobility of biomolecules is determined by transport and diffusion as well as molecular interactions and is crucial for many processes in living cells. Methods of fluorescence microscopy like confocal laser scanning microscopy (CLSM) can be used to characterize the intracellular distribution of fluorescently labeled biomolecules. Fluorescence correlation spectroscopy (FCS) is used to describe diffusion, transport and photo-physical processes quantitatively. As an alternative to FCS, spatially resolved measurements of mobilities can be implemented using a CLSM by utilizing the spatio-temporal information inscribed into the image by the scan process, referred to as raster image correlation spectroscopy (RICS). Here we present and discuss an extended approach, multiple scan speed image correlation spectroscopy (msICS), which benefits from the advantages of RICS, i.e. the use of widely available instrumentation and the extraction of spatially resolved mobility information, without the need of a priori knowledge of diffusion properties. In addition, msICS covers a broad dynamic range, generates correlation data comparable to FCS measurements, and allows to derive two-dimensional maps of diffusion coefficients. We show the applicability of msICS to fluorophores in solution and to free EGFP in living cells.
Direct Quantification of Solute Diffusivity in Agarose and Articular Cartilage Using Correlation Spectroscopy.

PubMed

Shoga, Janty S; Graham, Brian T; Wang, Liyun; Price, Christopher

2017-10-01

Articular cartilage is an avascular tissue; diffusive transport is critical for its homeostasis. While numerous techniques have been used to quantify diffusivity within porous, hydrated tissues and tissue engineered constructs, these techniques have suffered from issues regarding invasiveness and spatial resolution. In the present study, we implemented and compared two separate correlation spectroscopy techniques, fluorescence correlation spectroscopy (FCS) and raster image correlation spectroscopy (RICS), for the direct, and minimally-invasive quantification of fluorescent solute diffusion in agarose and articular cartilage. Specifically, we quantified the diffusional properties of fluorescein and Alexa Fluor 488-conjugated dextrans (3k and 10k) in aqueous solutions, agarose gels of varying concentration (i.e. 1, 3, 5%), and in different zones of juvenile bovine articular cartilage explants (i.e. superficial, middle, and deep). In agarose, properties of solute diffusion obtained via FCS and RICS were inversely related to molecule size, gel concentration, and applied strain. In cartilage, the diffusional properties of solutes were similarly dependent upon solute size, cartilage zone, and compressive strain; findings that agree with work utilizing other quantification techniques. In conclusion, this study established the utility of FCS and RICS as simple and minimally invasive techniques for quantifying microscale solute diffusivity within agarose constructs and articular cartilage explants.
Polymer diffusion in the interphase between surface and solution.

PubMed

Weger, Lukas; Weidmann, Monika; Ali, Wael; Hildebrandt, Marcus; Gutmann, Jochen Stefan; Hoffmann-Jacobsen, Kerstin

2018-05-22

Total internal reflection fluorescence correlation spectroscopy (TIR-FCS) is applied to study the self-diffusion of polyethylene glycol solutions in the presence of weakly attractive interfaces. Glass coverslips modified with aminopropyl- and propyl-terminated silanes are used to study the influence of solid surfaces on polymer diffusion. A model of three phases of polymer diffusion allows to describe the experimental fluorescence autocorrelation functions. Besides the two-dimensional diffusion of adsorbed polymer on the substrate and three-dimensional free diffusion in bulk solution, a third diffusion time scale is observed with intermediate diffusion times. This retarded three-dimensional diffusion in solution is assigned to long range effects of solid surfaces on diffusional dynamics of polymers. The respective diffusion constants show Rouse scaling (D~N -1 ) indicating a screening of hydrodynamic interactions by the presence of the surface. Hence, the presented TIR-FCS method proves to be a valuable tool to investigate the effect of surfaces on polymer diffusion beyond the first adsorbed polymer layer on the 100 nm length scale.
Convective-diffusion-based fluorescence correlation spectroscopy for detection of a trace amount of E. coli in water.

PubMed

Qing, De-Kui; Mengüç, M Pinar; Payne, Fred A; Danao, Mary-Grace C

2003-06-01

Fluorescence correlation spectroscopy (FCS) is adapted for a new procedure to detect trace amounts of Escherichia coli in water. The present concept is based on convective diffusion rather than Brownian diffusion and employs confocal microscopy as in traditional FCS. With this system it is possible to detect concentrations as small as 1.5 x 10(5) E. coli per milliliter (2.5 x 10(-16) M). This concentration corresponds to an approximately 1.0-nM level of Rhodamine 6G dyes. A detailed analysis of the optical system is presented, and further improvements for the procedure are discussed.
Determination of equilibrium and rate constants for complex formation by fluorescence correlation spectroscopy supplemented by dynamic light scattering and Taylor dispersion analysis.

PubMed

Zhang, Xuzhu; Poniewierski, Andrzej; Jelińska, Aldona; Zagożdżon, Anna; Wisniewska, Agnieszka; Hou, Sen; Hołyst, Robert

2016-10-04

The equilibrium and rate constants of molecular complex formation are of great interest both in the field of chemistry and biology. Here, we use fluorescence correlation spectroscopy (FCS), supplemented by dynamic light scattering (DLS) and Taylor dispersion analysis (TDA), to study the complex formation in model systems of dye-micelle interactions. In our case, dyes rhodamine 110 and ATTO-488 interact with three differently charged surfactant micelles: octaethylene glycol monododecyl ether C 12 E 8 (neutral), cetyltrimethylammonium chloride CTAC (positive) and sodium dodecyl sulfate SDS (negative). To determine the rate constants for the dye-micelle complex formation we fit the experimental data obtained by FCS with a new form of the autocorrelation function, derived in the accompanying paper. Our results show that the association rate constants for the model systems are roughly two orders of magnitude smaller than those in the case of the diffusion-controlled limit. Because the complex stability is determined by the dissociation rate constant, a two-step reaction mechanism, including the diffusion-controlled and reaction-controlled rates, is used to explain the dye-micelle interaction. In the limit of fast reaction, we apply FCS to determine the equilibrium constant from the effective diffusion coefficient of the fluorescent components. Depending on the value of the equilibrium constant, we distinguish three types of interaction in the studied systems: weak, intermediate and strong. The values of the equilibrium constant obtained from the FCS and TDA experiments are very close to each other, which supports the theoretical model used to interpret the FCS data.
Focal volume optics and experimental artifacts in confocal fluorescence correlation spectroscopy.

PubMed Central

Hess, Samuel T; Webb, Watt W

2002-01-01

Fluorescence correlation spectroscopy (FCS) can provide a wealth of information about biological and chemical systems on a broad range of time scales (<1 micros to >1 s). Numerical modeling of the FCS observation volume combined with measurements has revealed, however, that the standard assumption of a three-dimensional Gaussian FCS observation volume is not a valid approximation under many common measurement conditions. As a result, the FCS autocorrelation will contain significant, systematic artifacts that are most severe with confocal optics when using a large detector aperture and aperture-limited illumination. These optical artifacts manifest themselves in the fluorescence correlation as an apparent additional exponential component or diffusing species with significant (>30%) amplitude that can imply extraneous kinetics, shift the measured diffusion time by as much as approximately 80%, and cause the axial ratio to diverge. Artifacts can be minimized or virtually eliminated by using a small confocal detector aperture, underfilled objective back-aperture, or two-photon excitation. However, using a detector aperture that is smaller or larger than the optimal value (approximately 4.5 optical units) greatly reduces both the count rate per molecule and the signal-to-noise ratio. Thus, there is a tradeoff between optimizing signal-to-noise and reducing experimental artifacts in one-photon FCS. PMID:12324447
Nano-viscosity of supercooled liquid measured by fluorescence correlation spectroscopy: Pressure and temperature dependence and the density scaling

NASA Astrophysics Data System (ADS)

Meier, G.; Gapinski, J.; Ratajczyk, M.; Lettinga, M. P.; Hirtz, K.; Banachowicz, E.; Patkowski, A.

2018-03-01

The Stokes-Einstein relation allows us to calculate apparent viscosity experienced by tracers in complex media on the basis of measured self-diffusion coefficients. Such defined nano-viscosity values can be obtained through single particle techniques, like fluorescence correlation spectroscopy (FCS) and particle tracking (PT). In order to perform such measurements, as functions of pressure and temperature, a new sample cell was designed and is described in this work. We show that this cell in combination with a long working distance objective of the confocal microscope can be used for successful FCS, PT, and confocal imaging experiments in broad pressure (0.1-100 MPa) and temperature ranges. The temperature and pressure dependent nano-viscosity of a van der Waals liquid obtained from the translational diffusion coefficient measured in this cell by means of FCS obeys the same scaling as the rotational relaxation and macro-viscosity of the system.
Quantitative fluorescence imaging of protein diffusion and interaction in living cells.

PubMed

Capoulade, Jérémie; Wachsmuth, Malte; Hufnagel, Lars; Knop, Michael

2011-08-07

Diffusion processes and local dynamic equilibria inside cells lead to nonuniform spatial distributions of molecules, which are essential for processes such as nuclear organization and signaling in cell division, differentiation and migration. To understand these mechanisms, spatially resolved quantitative measurements of protein abundance, mobilities and interactions are needed, but current methods have limited capabilities to study dynamic parameters. Here we describe a microscope based on light-sheet illumination that allows massively parallel fluorescence correlation spectroscopy (FCS) measurements and use it to visualize the diffusion and interactions of proteins in mammalian cells and in isolated fly tissue. Imaging the mobility of heterochromatin protein HP1α (ref. 4) in cell nuclei we could provide high-resolution diffusion maps that reveal euchromatin areas with heterochromatin-like HP1α-chromatin interactions. We expect that FCS imaging will become a useful method for the precise characterization of cellular reaction-diffusion processes.
Monitoring the diffusion behavior of Na,K-ATPase by fluorescence correlation spectroscopy (FCS) upon fluorescence labelling with eGFP or Dreiklang

NASA Astrophysics Data System (ADS)

Junghans, Cornelia; Schmitt, Franz-Josef; Vukojević, Vladana; Friedrich, Thomas

2016-02-01

Measurement of lateral mobility of membraneembedded proteins in living cells with high spatial and temporal precision is a challenging task of optofluidics. Biological membranes are complex structures, whose physico-chemical properties depend on the local lipid composition, cholesterol content and the presence of integral or peripheral membrane proteins, which may be involved in supramolecular complexes or are linked to cellular matrix proteins or the cytoskeleton. The high proteinto- lipid ratios in biomembranes indicate that membrane proteins are particularly subject to molecular crowding, making it difficult to follow the track of individual molecules carrying a fluorescence label. Novel switchable fluorescence proteins such as Dreiklang [1], are, in principle, promising tools to study the diffusion behavior of individual molecules in situations of molecular crowding due to excellent spectral control of the ON- and OFF-switching process. In this work, we expressed an integral membrane transport protein, the Na,K-ATPase comprising the human α2-subunit carrying an N-terminal eGFP or Dreiklang tag and human β1-subunit, in HEK293T cells and measured autocorrelation curves by fluorescence correlation spectroscopy (FCS). Furthermore,we measured diffusion times and diffusion constants of eGFP and Dreiklang by FCS, first, in aqueous solution after purification of the proteins upon expression in E. coli, and, second, upon expression as soluble proteins in the cytoplasm of HEK293T cells. Our data show that the diffusion behavior of the purified eGFP and Dreiklang in solution as well as the properties of the proteins expressed in the cytoplasm are very similar. However, the autocorrelation curves of eGFP- and Dreiklanglabeled Na,K-ATPase measured in the plasma membrane exhibit marked differences, with the Dreiklang-labeled construct showing shorter diffusion times. This may be related to an additional, as yet unrecognized quenching process that occurs on the same time scale as the diffusion of the labeled complexes through the detection volume (1- 100 ms). Since the origin of this quenching process is currently unclear, care has to be taken when the Dreiklang label is intended to be used in FCS applications.
Monitoring the diffusion behavior of Na,K-ATPase by fluorescence correlation spectroscopy (FCS) upon fluorescence labelling with eGFP or Dreiklang

NASA Astrophysics Data System (ADS)

Junghans, Cornelia; Schmitt, Franz-Josef; Vukojević, Vladana; Friedrich, Thomas

2015-12-01

Measurement of lateral mobility of membraneembedded proteins in living cells with high spatial and temporal precision is a challenging task of optofluidics. Biological membranes are complex structures, whose physico-chemical properties depend on the local lipid composition, cholesterol content and the presence of integral or peripheral membrane proteins, which may be involved in supramolecular complexes or are linked to cellular matrix proteins or the cytoskeleton. The high proteinto- lipid ratios in biomembranes indicate that membrane proteins are particularly subject to molecular crowding, making it difficult to follow the track of individual molecules carrying a fluorescence label. Novel switchable fluorescence proteins such as Dreiklang [1], are, in principle, promising tools to study the diffusion behavior of individual molecules in situations of molecular crowding due to excellent spectral control of the ON- and OFF-switching process. In this work, we expressed an integral membrane transport protein, the Na,K-ATPase comprising the human α2-subunit carrying an N-terminal eGFP or Dreiklang tag and human β1-subunit, in HEK293T cells and measured autocorrelation curves by fluorescence correlation spectroscopy (FCS). Furthermore,we measured diffusion times and diffusion constants of eGFP and Dreiklang by FCS, first, in aqueous solution after purification of the proteins upon expression in E. coli, and, second, upon expression as soluble proteins in the cytoplasm of HEK293T cells. Our data show that the diffusion behavior of the purified eGFP and Dreiklang in solution as well as the properties of the proteins expressed in the cytoplasm are very similar. However, the autocorrelation curves of eGFP- and Dreiklanglabeled Na,K-ATPase measured in the plasma membrane exhibit marked differences, with the Dreiklang-labeled construct showing shorter diffusion times. This may be related to an additional, as yet unrecognized quenching process that occurs on the same time scale as the diffusion of the labeled complexes through the detection volume (1- 100 ms). Since the origin of this quenching process is currently unclear, care has to be taken when the Dreiklang label is intended to be used in FCS applications.
Dynamical studies of confined fluids and polymers

NASA Astrophysics Data System (ADS)

Grabowski, Christopher A.

Soft matter, a class of materials including polymers, colloids, and surfactant molecules, are ubiquitous in our everyday lives. Plastics, soaps, foods and living organisms are mostly comprised of soft materials. Research conducted to understand soft matter behavior at the molecular level is essential to create new materials with unique properties. Self-healing plastics, targeted drug delivery, and nanowire assemblies have all been further advanced by soft matter research. The author of this dissertation investigates fundamental soft matter systems, including polymer solutions and melts, colloid dispersions in polymer melts, and interfacial fluids. The dynamics of polymers and confined fluids were studied using the single-molecule sensitive technique of fluorescence correlation spectroscopy (FCS). Here, fluorescent dyes are attached to polymer coils or by introducing free dyes directly into the solution/film. Complementary experiments were also performed, utilizing atomic force microscopy (AFM) and ellipsometry. FCS and AFM experiments demonstrated the significant difference in properties of thin fluid films of the nearly spherical, nonpolar molecule TEHOS (tetrakis(2-ethylhexoxy)silane) when compared to its bulk counterpart. AFM experiments confirmed TEHOS orders in layers near a solid substrate. FCS experiments show that free dyes introduced in these thin films do not have a single diffusion coefficient, indicating that these films have heterogeneity at the molecular level. FCS experiments have been applied to study the diffusion of gold colloids. The diffusion of gold colloids in polymer melts was found to dramatically depart from the Stokes-Einstein prediction when colloid size was smaller than the surrounding polymer mesh size. This effect is explained by noting the viscosity experienced by the colloid is not equivalent to the overall bulk viscosity of the polymer melt. The conformational change of polymers immersed in a binary solvent was measured via FCS. This experiment was conducted to test a theory proposed by Brochard and de Gennes, who postulated a polymer chain undergoes a collapse and a dramatic re-swelling as the critical point of the binary mixture is approached. Measuring polymer chain diffusion as a function of temperature, this theory was confirmed. To my knowledge, this was the first experimental evidence of contraction/re-swelling for polymers in critical binary solvents.
Measuring the diffusion coefficient of ganglioside on cell membrane by fluorescence correlation spectroscopy

NASA Astrophysics Data System (ADS)

Dong, Shiqing; You, Minghai; Chen, Jianling; Zhou, Jie; Xie, Shusen; Yang, Hongqin

2017-06-01

The fluidity of proteins and lipids on cell membrane plays an important role in cell’s physiological functions. Fluorescence correlation spectroscopy (FCS) is an effective technique to detect the rapid dynamic behaviors of proteins and/or lipids in living cells. In this study, we used the rhodamine6G solution to optimize the FCS system. And, cholera toxin B subunit (CT-B) was used to label ganglioside on living Hela cell membranes. The diffusion time and coefficients of ganglioside can be obtained through fitting the autocorrelation curve based on the model of two-dimensional cell membrane. The results showed that the diffusion coefficients of ganglioside distributed within a wide range. It revealed the lateral diffusion of lipids on cell membrane was inhomogeneous, which was due to different microstructures of cytoplasmic membrane. The study provides a helpful method for further studying the dynamic characteristics of proteins and lipids molecules on living cell membrane.
Confocal fluorescence techniques in industrial application

NASA Astrophysics Data System (ADS)

Eggeling, Christian; Gall, Karsten; Palo, Kaupo; Kask, Peet; Brand, Leif

2003-06-01

The FCS+plus family of evaluation tools for confocal fluorescence spectroscopy, which was developed during recent years, offers a comprehensive view to a series of fluorescence properties. Originating in fluorescence correlation spectroscopy (FCS) and using similar experimental equipment, a system of signal processing methods such as fluorescence intensity distribution analysis (FIDA) was created to analyze in detail the fluctuation behavior of fluorescent particles within a small area of detection. Giving simultaneous access to molecular parameters like concentration, translational and rotational diffusion, molecular brightness, and multicolor coincidence, this portfolio was enhanced by more traditional techniques of fluorescence lifetime as well as time-resolved anisotropy determination. The cornerstones of the FCS+plus methodology will be shortly described. The inhibition of a phosphatase enzyme activity gives a comprehensive industrial application that demonstrates FCS+plus' versatility and its potential for pharmaceutical drug discovery.

Plasma membrane microorganization of LR73 multidrug-resistant cells revealed by FCS

NASA Astrophysics Data System (ADS)

Winckler, Pascale; Jaffiol, Rodolphe; Cailler, Aurélie; Morjani, Hamid; Jeannesson, Pierre; Deturche, Régis

2011-03-01

Tumoral cells could present a multidrug resistance (MDR) to chemotherapeutic treatments. This drug resistance would be associated to biomechanisms occurring at the plasma membrane level, involving modification of membrane fluidity, drug permeability, presence of microdomains (rafts, caveolae...), and membrane proteins overexpression such as Pglycoprotein. Fluorescence correlation spectroscopy (FCS) is the relevant method to investigate locally the fluidity of biological membranes through the lateral diffusion of a fluorescent membrane probe. Thus, we use FCS to monitor the plasma membrane local organization of LR73 carcinoma cells and three derived multidrug-resistant cancer cells lines. Measurements were conducted at the single cell level, which enabled us to get a detailed overview of the plasma membrane microviscosity distribution of each cell line studied. Moreover, we propose 2D diffusion simulation based on a Monte Carlo model to investigate the membrane organisation in terms of microdomains. This simulation allows us to relate the differences in the fluidity distributions with microorganization changes in plasma membrane of MDR cells.
Using fluorescence correlation spectroscopy to study conformational changes in denatured proteins.

PubMed

Sherman, Eilon; Itkin, Anna; Kuttner, Yosef Yehuda; Rhoades, Elizabeth; Amir, Dan; Haas, Elisha; Haran, Gilad

2008-06-01

Fluorescence correlation spectroscopy (FCS) is a sensitive analytical tool that allows dynamics and hydrodynamics of biomolecules to be studied under a broad range of experimental conditions. One application of FCS of current interest is the determination of the size of protein molecules in the various states they sample along their folding reaction coordinate, which can be accessed through the measurement of diffusion coefficients. It has been pointed out that the analysis of FCS curves is prone to artifacts that may lead to erroneous size determination. To set the stage for FCS studies of unfolded proteins, we first show that the diffusion coefficients of small molecules as well as proteins can be determined accurately even in the presence of high concentrations of co-solutes that change the solution refractive index significantly. Indeed, it is found that the Stokes-Einstein relation between the measured diffusion coefficient and solution viscosity holds even in highly concentrated glycerol or guanidinium hydrochloride (GuHCl) solutions. These measurements form the basis for an investigation of the structure of the denatured state of two proteins, the small protein L and the larger, three-domain protein adenylate kinase (AK). FCS is found useful for probing expansion in the denatured state beyond the unfolding transition. It is shown that the denatured state of protein L expands as the denaturant concentration increases, in a process akin to the transition from a globule to a coil in polymers. This process continues at least up to 5 M GuHCl. On the other hand, the denatured state of AK does not seem to expand much beyond 2 M GuHCl, a result that is in qualitative accord with single-molecule fluorescence histograms. Because both the unfolding transition and the coil-globule transition of AK occur at a much lower denaturant concentration than those of protein L, a possible correlation between the two phenomena is suggested.
Imaging fluorescence-correlation spectroscopy for measuring fast surface diffusion at liquid/solid interfaces.

PubMed

Cooper, Justin T; Harris, Joel M

2014-08-05

The development of techniques to probe interfacial molecular transport is important for understanding and optimizing surface-based analytical methods including surface-enhanced spectroscopies, biological assays, and chemical separations. Single-molecule-fluorescence imaging and tracking has been used to measure lateral diffusion rates of fluorescent molecules at surfaces, but the technique is limited to the study of slower diffusion, where molecules must remain relatively stationary during acquisition of an image in order to build up sufficient intensity in a spot to detect and localize the molecule. Although faster time resolution can be achieved by fluorescence-correlation spectroscopy (FCS), where intensity fluctuations in a small spot are related to the motions of molecules on the surface, long-lived adsorption events arising from surface inhomogeneity can overwhelm the correlation measurement and mask the surface diffusion of the moving population. Here, we exploit a combination of these two techniques, imaging-FCS, for measurement of fast interfacial transport at a model chromatographic surface. This is accomplished by rapid imaging of the surface using an electron-multiplied-charged-coupled-device (CCD) camera, while limiting the acquisition to a small area on the camera to allow fast framing rates. The total intensity from the sampled region is autocorrelated to determine surface diffusion rates of molecules with millisecond time resolution. The technique allows electronic control over the acquisition region, which can be used to avoid strong adsorption sites and thus minimize their contribution to the measured autocorrelation decay and to vary the acquisition area to resolve surface diffusion from adsorption and desorption kinetics. As proof of concept, imaging-FCS was used to measure surface diffusion rates, interfacial populations, and adsorption-desorption rates of 1,1'-dioctadecyl-3,3,3'3'-tetramethylindocarbocyanine (DiI) on planar C18- and C1-modified surfaces.
Apparent Anomalous Diffusion in the Cytoplasm of Human Cells: The Effect of Probes' Polydispersity.

PubMed

Kalwarczyk, Tomasz; Kwapiszewska, Karina; Szczepanski, Krzysztof; Sozanski, Krzysztof; Szymanski, Jedrzej; Michalska, Bernadeta; Patalas-Krawczyk, Paulina; Duszynski, Jerzy; Holyst, Robert

2017-10-26

This work, based on in vivo and in vitro measurements, as well as in silico simulations, provides a consistent analysis of diffusion of polydisperse nanoparticles in the cytoplasm of living cells. Using the example of fluorescence correlation spectroscopy (FCS), we show the effect of polydispersity of probes on the experimental results. Although individual probes undergo normal diffusion, in the ensemble of probes, an effective broadening of the distribution of diffusion times occurs-similar to anomalous diffusion. We introduced fluorescently labeled dextrans into the cytoplasm of HeLa cells and found that cytoplasmic hydrodynamic drag, exponentially dependent on probe size, extraordinarily broadens the distribution of diffusion times across the focal volume. As a result, the in vivo FCS data were effectively fitted with the anomalous subdiffusion model while for a monodisperse probe the normal diffusion model was most suitable. Diffusion time obtained from the anomalous diffusion model corresponds to a probe whose size is determined by the weight-average molecular weight of the polymer. The apparent anomaly exponent decreases with increasing polydispersity of the probes. Our results and methodology can be applied in intracellular studies of the mobility of nanoparticles, polymers, or oligomerizing proteins.
Fluorescence Correlation Spectroscopy and Nonlinear Stochastic Reaction-Diffusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Del Razo, Mauricio; Pan, Wenxiao; Qian, Hong

2014-05-30

The currently existing theory of fluorescence correlation spectroscopy (FCS) is based on the linear fluctuation theory originally developed by Einstein, Onsager, Lax, and others as a phenomenological approach to equilibrium fluctuations in bulk solutions. For mesoscopic reaction-diffusion systems with nonlinear chemical reactions among a small number of molecules, a situation often encountered in single-cell biochemistry, it is expected that FCS time correlation functions of a reaction-diffusion system can deviate from the classic results of Elson and Magde [Biopolymers (1974) 13:1-27]. We first discuss this nonlinear effect for reaction systems without diffusion. For nonlinear stochastic reaction-diffusion systems there are no closedmore » solutions; therefore, stochastic Monte-Carlo simulations are carried out. We show that the deviation is small for a simple bimolecular reaction; the most significant deviations occur when the number of molecules is small and of the same order. Extending Delbrück-Gillespie’s theory for stochastic nonlinear reactions with rapidly stirring to reaction-diffusion systems provides a mesoscopic model for chemical and biochemical reactions at nanometric and mesoscopic level such as a single biological cell.« less
Fluorescence correlation spectroscopy experiments to quantify free diffusion coefficients in reaction-diffusion systems: The case of Ca2 + and its dyes

NASA Astrophysics Data System (ADS)

Sigaut, Lorena; Villarruel, Cecilia; Ponce, María Laura; Ponce Dawson, Silvina

2017-06-01

Many cell signaling pathways involve the diffusion of messengers that bind and unbind to and from intracellular components. Quantifying their net transport rate under different conditions then requires having separate estimates of their free diffusion coefficient and binding or unbinding rates. In this paper, we show how performing sets of fluorescence correlation spectroscopy (FCS) experiments under different conditions, it is possible to quantify free diffusion coefficients and on and off rates of reaction-diffusion systems. We develop the theory and present a practical implementation for the case of the universal second messenger, calcium (Ca2 +) and single-wavelength dyes that increase their fluorescence upon Ca2 + binding. We validate the approach with experiments performed in aqueous solutions containing Ca2 + and Fluo4 dextran (both in its high and low affinity versions). Performing FCS experiments with tetramethylrhodamine-dextran in Xenopus laevis oocytes, we infer the corresponding free diffusion coefficients in the cytosol of these cells. Our approach can be extended to other physiologically relevant reaction-diffusion systems to quantify biophysical parameters that determine the dynamics of various variables of interest.
Mapping Diffusion in a Living Cell via the Phasor Approach

PubMed Central

Ranjit, Suman; Lanzano, Luca; Gratton, Enrico

2014-01-01

Diffusion of a fluorescent protein within a cell has been measured using either fluctuation-based techniques (fluorescence correlation spectroscopy (FCS) or raster-scan image correlation spectroscopy) or particle tracking. However, none of these methods enables us to measure the diffusion of the fluorescent particle at each pixel of the image. Measurement using conventional single-point FCS at every individual pixel results in continuous long exposure of the cell to the laser and eventual bleaching of the sample. To overcome this limitation, we have developed what we believe to be a new method of scanning with simultaneous construction of a fluorescent image of the cell. In this believed new method of modified raster scanning, as it acquires the image, the laser scans each individual line multiple times before moving to the next line. This continues until the entire area is scanned. This is different from the original raster-scan image correlation spectroscopy approach, where data are acquired by scanning each frame once and then scanning the image multiple times. The total time of data acquisition needed for this method is much shorter than the time required for traditional FCS analysis at each pixel. However, at a single pixel, the acquired intensity time sequence is short; requiring nonconventional analysis of the correlation function to extract information about the diffusion. These correlation data have been analyzed using the phasor approach, a fit-free method that was originally developed for analysis of FLIM images. Analysis using this method results in an estimation of the average diffusion coefficient of the fluorescent species at each pixel of an image, and thus, a detailed diffusion map of the cell can be created. PMID:25517145
APOE Polymorphism Affects Brain Default Mode Network in Healthy Young Adults

PubMed Central

Su, Yun Yan; Liang, Xue; Schoepf, U. Joseph; Varga-Szemes, Akos; West, Henry C.; Qi, Rongfeng; Kong, Xiang; Chen, Hui Juan; Lu, Guang Ming; Zhang, Long Jiang

2015-01-01

Abstract To investigate the effect of apolipoprotein E (APOE) gene polymorphism on the resting-state brain function, structure, and blood flow in healthy adults younger than 35 years, using multimodality magnetic resonance (MR) imaging. Seventy-six healthy adults (34 men, 23.7 ± 2.8 y; 31 APOE ε4/ε3 carriers, 31 ε3/ε3 carriers, and 14 ε2/ε3 carriers) were included. For resting-state functional MRI data, default mode network (DMN) and amplitude of low-frequency fluctuation maps were extracted and analyzed. Voxel-based morphometry, diffusion tensor imaging from structural imaging, and cerebral blood flow based on arterial spin labeling MR imaging were also analyzed. Correlation analysis was performed between the above mentioned brain parameters and neuropsychological tests. There were no differences in neuropsychological performances, amplitude of low-frequency fluctuation, gray/white matter volumes, fractional anisotropy, mean diffusivity, or whole brain cerebral blood flow among the 3 groups. As for DMN, the ε4/ε3 group showed increased functional connectivities (FCs) in the left medial prefrontal cortex and bilateral posterior cingulate cortices/precuneus compared with the ε3/ε3 group, and increased FCs in the left medial prefrontal cortex and right temporal lobe compared with the ε2/ε3 group (P < 0.05, Alphasim corrected). No differences of DMN FCs were found between the ε2/ε3 and ε3/ε3 groups. FCs in the right temporal lobe positively correlated with the performances of vocabulary learning, delayed recall, and graph recall in all participants (P < 0.05). APOE ε4 carriers exhibited significantly increased DMN FCs when compared with ε3 and ε2 carriers. The ε4 affects DMN FCs before brain structure and blood flow in cognitively intact young patients, suggesting DMN FC may serve as a potential biomarker for the detection of early manifestations of genetic effect. PMID:26717353
Diffusion of lipids and GPI-anchored proteins in actin-free plasma membrane vesicles measured by STED-FCS

PubMed Central

Schneider, Falk; Waithe, Dominic; Clausen, Mathias P.; Galiani, Silvia; Koller, Thomas; Ozhan, Gunes; Eggeling, Christian; Sezgin, Erdinc

2017-01-01

Diffusion and interaction dynamics of molecules at the plasma membrane play an important role in cellular signaling and are suggested to be strongly associated with the actin cytoskeleton. Here we use superresolution STED microscopy combined with fluorescence correlation spectroscopy (STED-FCS) to access and compare the diffusion characteristics of fluorescent lipid analogues and GPI-anchored proteins (GPI-APs) in the live-cell plasma membrane and in actin cytoskeleton–free, cell-derived giant plasma membrane vesicles (GPMVs). Hindered diffusion of phospholipids and sphingolipids is abolished in the GPMVs, whereas transient nanodomain incorporation of ganglioside lipid GM1 is apparent in both the live-cell membrane and GPMVs. For GPI-APs, we detect two molecular pools in living cells; one pool shows high mobility with transient incorporation into nanodomains, and the other pool forms immobile clusters, both of which disappear in GPMVs. Our data underline the crucial role of the actin cortex in maintaining hindered diffusion modes of many but not all of the membrane molecules and highlight a powerful experimental approach to decipher specific influences on molecular plasma membrane dynamics. PMID:28404749
Dynamics of nanoparticles in complex fluids

NASA Astrophysics Data System (ADS)

Omari, Rami A.

Soft matter is a subfield of condensed matter including polymers, colloidal dispersions, surfactants, and liquid crystals. These materials are familiar from our everyday life- glues, paints, soaps, and plastics are examples of soft materials. Many phenomena in these systems have the same underlying physical mechanics. Moreover, it has been recognized that combinations of these systems, like for example polymers and colloids, exhibit new properties which are not found in each system separately. These mixed systems have a higher degree of complexity than the separate systems. In order to understand their behavior, knowledge from each subfields of soft matter has to be put together. One of these complex systems is the mixture of nanoparticles with macromolecules such as polymers, proteins, etc. Understanding the interactions in these systems is essential for solving various problems in technological and medical fields, such as developing high performance polymeric materials, chromatography, and drug delivery vehicles. The author of this dissertation investigates fundemental soft matter systems, including colloid dispersions in polymer solutions and binary mixture. The diffusion of gold nanoparticles in semidilute and entangled solutions of polystyrene (PS) in toluene were studied using fluorescence correlation spectroscopy (FCS). In our experiments, the particle radius (R ≈ 2.5 nm) was much smaller compared to the radius of gyration of the chain but comparable to the average mesh size of the fluctuating polymer network. The diffusion coefficient (D) of the particles decreased monotonically with polymer concentration and it can be fitted with a stretched exponential function. At high concentration of the polymer, a clear subdiffusive motion of the particles was observed. The results were compared with the diffusion of free dyes, which showed normal diffusive behavior for all concentrations. In another polymer solution, poly ethylene glycol (PEG) in water, the diffusion of the gold nanoparticles depends on the dimentionless length scale R/zeta, where R is the radius of the nanoparticle and zeta is the average mesh size of the fluctuating polymer network. FCS were used to study the critical adsorption on curved surfaces by utilizing spherical nanoparticles immersed in a critical binary liquid mixture of 2,6 lutidine + water. The temperature dependence of the adsorbed film thickness and excess adsorption was determined from FCS measurements of the enlarged effective hydrodynamic radius of the particles. Our results indicated that the adsorbed film thickness is of the order of correlation length associated with concentration fluctuations. The excess adsorption per unit area increases following a power law in reduced temperature with an exponent of -1, which is the mean-field value for the bulk susceptibility exponent. The kinetics of adsorption of gold nanoparticles in polymer solutions on silicon substrate was studied using ellipsometry by measuring the thickness of the adsorbed layer versus time. The data showed an exponential growth with relaxation time constants, which is proportional to the diffusion of the gold nanoparticles in polymer solution.
Controlled release of functional proteins through designer self-assembling peptide nanofiber hydrogel scaffold

PubMed Central

Koutsopoulos, Sotirios; Unsworth, Larry D.; Nagai, Yusuke; Zhang, Shuguang

2009-01-01

The release kinetics for a variety of proteins of a wide range of molecular mass, hydrodynamic radii, and isoelectric points through a nanofiber hydrogel scaffold consisting of designer self-assembling peptides were studied by using single-molecule fluorescence correlation spectroscopy (FCS). In contrast to classical diffusion experiments, the single-molecule approach allowed for the direct determination of diffusion coefficients for lysozyme, trypsin inhibitor, BSA, and IgG both inside the hydrogel and after being released into the solution. The results of the FCS analyses and the calculated pristine in-gel diffusion coefficients were compared with the values obtained from the Stokes–Einstein equation, Fickian diffusion models, and the literature. The release kinetics suggested that protein diffusion through nanofiber hydrogels depended primarily on the size of the protein. Protein diffusivities decreased, with increasing hydrogel nanofiber density providing a means of controlling the release kinetics. Secondary and tertiary structure analyses and biological assays of the released proteins showed that encapsulation and release did not affect the protein conformation and functionality. Our results show that this biocompatible and injectable designer self-assembling peptide hydrogel system may be useful as a carrier for therapeutic proteins for sustained release applications. PMID:19273853
Continuous Fluorescence Microphotolysis and Correlation Spectroscopy Using 4Pi Microscopy

PubMed Central

Arkhipov, Anton; Hüve, Jana; Kahms, Martin; Peters, Reiner; Schulten, Klaus

2007-01-01

Continuous fluorescence microphotolysis (CFM) and fluorescence correlation spectroscopy (FCS) permit measurement of molecular mobility and association reactions in single living cells. CFM and FCS complement each other ideally and can be realized using identical equipment. So far, the spatial resolution of CFM and FCS was restricted by the resolution of the light microscope to the micrometer scale. However, cellular functions generally occur on the nanometer scale. Here, we develop the theoretical and computational framework for CFM and FCS experiments using 4Pi microscopy, which features an axial resolution of ∼100 nm. The framework, taking the actual 4Pi point spread function of the instrument into account, was validated by measurements on model systems, employing 4Pi conditions or normal confocal conditions together with either single- or two-photon excitation. In all cases experimental data could be well fitted by computed curves for expected diffusion coefficients, even when the signal/noise ratio was small due to the small number of fluorophores involved. PMID:17704168
Fluorescence fluctuation spectroscopy for clinical applications

NASA Astrophysics Data System (ADS)

Olson, Eben

Fluorescence correlation spectroscopy (FCS) and the related techniques of brightness analysis have become standard tools in biological and biophysical research. By analyzing the statistics of fluorescence emitted from a restricted volume, a number of parameters including concentrations, diffusion coefficients and chemical reaction rates can be determined. The single-molecule sensitivity, spectral selectivity, small sample volume and non-perturbative measurement mechanism of FCS make it an excellent technique for the study of molecular interactions. However, its adoption outside of the research laboratory has been limited. Potential reasons for this include the cost and complexity of the required apparatus. In this work, the application of fluorescence fluctuation analysis to several clinical problems is considered. Optical designs for FCS instruments which reduce the cost and increase alignment tolerance are presented. Brightness analysis of heterogenous systems, with application to the characterization of protein aggregates and multimer distributions, is considered. Methods for FCS-based assays of two clinically relevant proteins, von Willebrand factor and haptoglobin, are presented as well.
Surface Transient Binding-Based Fluorescence Correlation Spectroscopy (STB-FCS), a Simple and Easy-to-Implement Method to Extend the Upper Limit of the Time Window to Seconds.

PubMed

Peng, Sijia; Wang, Wenjuan; Chen, Chunlai

2018-05-10

Fluorescence correlation spectroscopy is a powerful single-molecule tool that is able to capture kinetic processes occurring at the nanosecond time scale. However, the upper limit of its time window is restricted by the dwell time of the molecule of interest in the confocal detection volume, which is usually around submilliseconds for a freely diffusing biomolecule. Here, we present a simple and easy-to-implement method, named surface transient binding-based fluorescence correlation spectroscopy (STB-FCS), which extends the upper limit of the time window to seconds. We further demonstrated that STB-FCS enables capture of both intramolecular and intermolecular kinetic processes whose time scales cross several orders of magnitude.
Remote excitation fluorescence correlation spectroscopy using silver nanowires

NASA Astrophysics Data System (ADS)

Su, Liang; Yuan, Haifeng; Lu, Gang; Hofkens, Johan; Roeffaers, Maarten; Uji-i, Hiroshi

2014-11-01

Fluorescence correlation spectroscopy (FCS), a powerful tool to resolve local properties, dynamical process of molecules, rotational and translational diffusion motions, relies on the fluctuations of florescence observables in the observation volume. In the case of rare transition events or small dynamical fluctuations, FCS requires few molecules or even single molecules in the observation volume at a time to minimize the background signals. Metal nanoparticle which possess unique localized surface plasmon resonance (LSPR) have been used to reduce the observation volume down to sub-diffraction limited scale while maintain at high analyst concentration up to tens of micromolar. Nevertheless, the applications of functionalized nanoparticles in living cell are limited due to the continuous diffusion after cell uptake, which makes it difficult to target the region of interests in the cell. In this work, we demonstrate the use of silver nanowires for remote excitation FCS on fluorescent molecules in solution. By using propagation surface plasmon polaritons (SPPs) which supported by the silver nanowire to excite the fluorescence, both illumination and observation volume can be reduced simultaneously. In such a way, less perturbation is induced to the target region, and this will broaden the application scope of silver nanowire as tip in single cell endoscopy.
Utilization and Maintenance of the Federal Catalog System (FCS)

NASA Technical Reports Server (NTRS)

1989-01-01

The Federal Catalog System (FCS) was established and substantiated by law to aid the national economy and promote greater efficiency in supply management operations throughout the Federal Government. This Handbook establishes policies and procedures to be followed by NASA installations and certain contractors in cataloging items of supply in the Federal Catalog System and prescribes use of the system in supply management operations. This Handbook is not intended to duplicate the Federal Cataloging Manuals or Federal Cataloging Handbooks. For the most part, it describes actions that are peculiar to NASA.
Exploring the Dynamics of Cell Processes through Simulations of Fluorescence Microscopy Experiments

PubMed Central

Angiolini, Juan; Plachta, Nicolas; Mocskos, Esteban; Levi, Valeria

2015-01-01

Fluorescence correlation spectroscopy (FCS) methods are powerful tools for unveiling the dynamical organization of cells. For simple cases, such as molecules passively moving in a homogeneous media, FCS analysis yields analytical functions that can be fitted to the experimental data to recover the phenomenological rate parameters. Unfortunately, many dynamical processes in cells do not follow these simple models, and in many instances it is not possible to obtain an analytical function through a theoretical analysis of a more complex model. In such cases, experimental analysis can be combined with Monte Carlo simulations to aid in interpretation of the data. In response to this need, we developed a method called FERNET (Fluorescence Emission Recipes and Numerical routines Toolkit) based on Monte Carlo simulations and the MCell-Blender platform, which was designed to treat the reaction-diffusion problem under realistic scenarios. This method enables us to set complex geometries of the simulation space, distribute molecules among different compartments, and define interspecies reactions with selected kinetic constants, diffusion coefficients, and species brightness. We apply this method to simulate single- and multiple-point FCS, photon-counting histogram analysis, raster image correlation spectroscopy, and two-color fluorescence cross-correlation spectroscopy. We believe that this new program could be very useful for predicting and understanding the output of fluorescence microscopy experiments. PMID:26039162
Dual-color dual-focus line-scanning FCS for quantitative analysis of receptor-ligand interactions in living specimens.

PubMed

Dörlich, René M; Chen, Qing; Niklas Hedde, Per; Schuster, Vittoria; Hippler, Marc; Wesslowski, Janine; Davidson, Gary; Nienhaus, G Ulrich

2015-05-07

Cellular communication in multi-cellular organisms is mediated to a large extent by a multitude of cell-surface receptors that bind specific ligands. An in-depth understanding of cell signaling networks requires quantitative information on ligand-receptor interactions within living systems. In principle, fluorescence correlation spectroscopy (FCS) based methods can provide such data, but live-cell applications have proven extremely challenging. Here, we have developed an integrated dual-color dual-focus line-scanning fluorescence correlation spectroscopy (2c2f lsFCS) technique that greatly facilitates live-cell and tissue experiments. Absolute ligand and receptor concentrations and their diffusion coefficients within the cell membrane can be quantified without the need to perform additional calibration experiments. We also determine the concentration of ligands diffusing in the medium outside the cell within the same experiment by using a raster image correlation spectroscopy (RICS) based analysis. We have applied this robust technique to study the interactions of two Wnt antagonists, Dickkopf1 and Dickkopf2 (Dkk1/2), to their cognate receptor, low-density-lipoprotein-receptor related protein 6 (LRP6), in the plasma membrane of living HEK293T cells. We obtained significantly lower affinities than previously reported using in vitro studies, underscoring the need to measure such data on living cells or tissues.
A study of the diffusion dynamics and concentration distribution of gold nanospheres (GNSs) without fluorescent labeling inside live cells using fluorescence single particle spectroscopy.

PubMed

Liu, Fangchao; Dong, Chaoqing; Ren, Jicun

2018-03-15

Colloidal gold nanospheres (GNSs) have become important nanomaterials in biomedical applications due to their special optical properties, good chemical stability, and biocompatibility. However, measuring the diffusion coefficients or concentration distribution of GNSs within live cells accurately without any extra fluorescent labeling in situ has still not been resolved. In this work, a single particle method is developed to study the concentration distribution of folic acid-modified GNSs (FA-GNSs) internalized via folate receptors, and investigates their diffusion dynamics within live cells using single particle fluorescence correlation spectroscopy (FCS). We optimized the experimental conditions and verified the feasibility of 30 nm GNSs without extra fluorescence labeling being used for single particle detection inside live cells. Then, the FCS characterization strategy was used to measure the concentration and diffusion coefficient distributions of GNSs inside live cells and the obtained results were basically in agreement with those obtained by TEM. The results demonstrate that our strategy is characterized as an in situ, nondestructive, rapid and dynamic method for the assay of live cells, and it may be widely used in the further design of GNP-based drug delivery and therapeutics.
Cortical actin networks induce spatio-temporal confinement of phospholipids in the plasma membrane - a minimally invasive investigation by STED-FCS

NASA Astrophysics Data System (ADS)

Andrade, Débora M.; Clausen, Mathias P.; Keller, Jan; Mueller, Veronika; Wu, Congying; Bear, James E.; Hell, Stefan W.; Lagerholm, B. Christoffer; Eggeling, Christian

2015-06-01

Important discoveries in the last decades have changed our view of the plasma membrane organisation. Specifically, the cortical cytoskeleton has emerged as a key modulator of the lateral diffusion of membrane proteins. Cytoskeleton-dependent compartmentalised lipid diffusion has been proposed, but this concept remains controversial because this phenomenon has thus far only been observed with artefact-prone probes in combination with a single technique: single particle tracking. In this paper, we report the first direct observation of compartmentalised phospholipid diffusion in the plasma membrane of living cells using a minimally invasive, fluorescent dye labelled lipid analogue. These observations were made using optical STED nanoscopy in combination with fluorescence correlation spectroscopy (STED-FCS), a technique which allows the study of membrane dynamics on a sub-millisecond time-scale and with a spatial resolution of down to 40 nm. Specifically, we find that compartmentalised phospholipid diffusion depends on the cortical actin cytoskeleton, and that this constrained diffusion is directly dependent on the F-actin branching nucleator Arp2/3. These findings provide solid evidence that the Arp2/3-dependent cortical actin cytoskeleton plays a pivotal role in the dynamic organisation of the plasma membrane, potentially regulating fundamental cellular processes.

Cortical actin networks induce spatio-temporal confinement of phospholipids in the plasma membrane--a minimally invasive investigation by STED-FCS.

PubMed

Andrade, Débora M; Clausen, Mathias P; Keller, Jan; Mueller, Veronika; Wu, Congying; Bear, James E; Hell, Stefan W; Lagerholm, B Christoffer; Eggeling, Christian

2015-06-29

Important discoveries in the last decades have changed our view of the plasma membrane organisation. Specifically, the cortical cytoskeleton has emerged as a key modulator of the lateral diffusion of membrane proteins. Cytoskeleton-dependent compartmentalised lipid diffusion has been proposed, but this concept remains controversial because this phenomenon has thus far only been observed with artefact-prone probes in combination with a single technique: single particle tracking. In this paper, we report the first direct observation of compartmentalised phospholipid diffusion in the plasma membrane of living cells using a minimally invasive, fluorescent dye labelled lipid analogue. These observations were made using optical STED nanoscopy in combination with fluorescence correlation spectroscopy (STED-FCS), a technique which allows the study of membrane dynamics on a sub-millisecond time-scale and with a spatial resolution of down to 40 nm. Specifically, we find that compartmentalised phospholipid diffusion depends on the cortical actin cytoskeleton, and that this constrained diffusion is directly dependent on the F-actin branching nucleator Arp2/3. These findings provide solid evidence that the Arp2/3-dependent cortical actin cytoskeleton plays a pivotal role in the dynamic organisation of the plasma membrane, potentially regulating fundamental cellular processes.
Cortical actin networks induce spatio-temporal confinement of phospholipids in the plasma membrane – a minimally invasive investigation by STED-FCS

PubMed Central

Andrade, Débora M.; Clausen, Mathias P.; Keller, Jan; Mueller, Veronika; Wu, Congying; Bear, James E.; Hell, Stefan W.; Lagerholm, B. Christoffer; Eggeling, Christian

2015-01-01

Important discoveries in the last decades have changed our view of the plasma membrane organisation. Specifically, the cortical cytoskeleton has emerged as a key modulator of the lateral diffusion of membrane proteins. Cytoskeleton-dependent compartmentalised lipid diffusion has been proposed, but this concept remains controversial because this phenomenon has thus far only been observed with artefact-prone probes in combination with a single technique: single particle tracking. In this paper, we report the first direct observation of compartmentalised phospholipid diffusion in the plasma membrane of living cells using a minimally invasive, fluorescent dye labelled lipid analogue. These observations were made using optical STED nanoscopy in combination with fluorescence correlation spectroscopy (STED-FCS), a technique which allows the study of membrane dynamics on a sub-millisecond time-scale and with a spatial resolution of down to 40 nm. Specifically, we find that compartmentalised phospholipid diffusion depends on the cortical actin cytoskeleton, and that this constrained diffusion is directly dependent on the F-actin branching nucleator Arp2/3. These findings provide solid evidence that the Arp2/3-dependent cortical actin cytoskeleton plays a pivotal role in the dynamic organisation of the plasma membrane, potentially regulating fundamental cellular processes. PMID:26118385
A 32-channel photon counting module with embedded auto/cross-correlators for real-time parallel fluorescence correlation spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, S.; Labanca, I.; Rech, I.

2014-10-15

Fluorescence correlation spectroscopy (FCS) is a well-established technique to study binding interactions or the diffusion of fluorescently labeled biomolecules in vitro and in vivo. Fast FCS experiments require parallel data acquisition and analysis which can be achieved by exploiting a multi-channel Single Photon Avalanche Diode (SPAD) array and a corresponding multi-input correlator. This paper reports a 32-channel FPGA based correlator able to perform 32 auto/cross-correlations simultaneously over a lag-time ranging from 10 ns up to 150 ms. The correlator is included in a 32 × 1 SPAD array module, providing a compact and flexible instrument for high throughput FCS experiments.more » However, some inherent features of SPAD arrays, namely afterpulsing and optical crosstalk effects, may introduce distortions in the measurement of auto- and cross-correlation functions. We investigated these limitations to assess their impact on the module and evaluate possible workarounds.« less
Remote temperature measurements in femto-liter volumes using dual-focus-Fluorescence Correlation Spectroscopy.

PubMed

Müller, Claus B; Weiss, Kerstin; Loman, Anastasia; Enderlein, Jörg; Richtering, Walter

2009-05-07

Remote temperature measurements in microfluidic devices with micrometer spatial resolution are important for many applications in biology, biochemistry and chemistry. The most popular methods use the temperature-dependent fluorescence lifetime of Rhodamine B, or the temperature-dependent size of thermosensitive materials such as microgel particles. Here, we use the recently developed method of dual-focus fluorescence correlation spectroscopy (2fFCS) for measuring the absolute diffusion coefficient of small fluorescent molecules at nanomolar concentrations and show how these data can be used for remote temperature measurements on a micrometer scale. We perform comparative temperature measurements using all three methods and show that the accuracy of 2fFCS is comparable or even better than that achievable with Rhodamine B fluorescence lifetime measurements. The temperature dependent microgel swelling leads to an enhanced accuracy within a narrow temperature range around the volume phase transition temperature, but requires the availability of specific microgels, whereas 2fFCS is applicable under very general conditions.
Monitoring and Manipulating Motions of Single Molecules/Nanoparticles

NASA Astrophysics Data System (ADS)

Chen, Fang

This dissertation has two main research components: 1. the study of mass transport in confined environments; 2. the effort toward driving a molecular car on a solid surface. Understanding mass transport processes, e.g., diffusion, migration, and adsorption/desorption in confined space is important not only to fundamental sciences but also to advanced applications. So far, they are poorly understood because of technical challenges: insufficient spatial and/or temporal resolutions. In this dissertation, we made efforts toward understanding molecular/particular dynamics in confined space by combining a recently developed super resolution technique, stimulated depletion emission microscopy (STED), with the high temporal resolution technique, fluorescence correlation spectroscopy (FCS). We first explored the feasibility of using conventional FCS to study diffusion in a model confined space: cylindrical pores. Since there is no analytical solution to solve the autocorrelation function (ACF) in confined space, we simulated single particle diffusion in hundred-nanometer pores using Monte Carlo simulation. We found that confined 2D diffusion and unconfined 1D diffusion dynamics are separated in both intensity traces and autocorrelation functions, which gives a new opportunity to extract the axial diffusion coefficient in cylindrical pores. We then experimentally studied 45 nm particles diffusing in 300 nm alumina pores. The acquired axial diffusion coefficient is consistent with the expected value. Conventional confocal FCS is insufficient to resolve lateral diffusion in confined space because of the diffraction limit in spatial resolution. To pave the way of using STED microscopy to study the anisotropic diffusion in confined space, we theoretically investigated STED-FCS in cylindrical pores. It showed that by reducing the spatial resolution from 250 nm to 50 nm in STED microscopy, we would be able to determine both lateral and axial diffusion coefficients in hundred-nanometer pores in theory. We then experimentally studied nanoparticles diffusing on membrane filters containing 200 nm polyethyleneglycol- or C18-modified pores. Using STED microscopy, we resolved for the first time how small particles are retained by the pores. Trapping by the pore entrances rather than adsorption is responsible for the retention. Further studies on C18-modified pores showed consistency in Gibbs free energy about the retention process. In addition, in order to understand how nanoparticles interact with the surface when they are forced to be on, or very close to, the surface, we studied nanosecond rotation dynamics of gold nanorods with one end attached on the surface. We found that the nanorod motion is dominated by van der Waals interaction-induced immobilization rather Brownian rotational diffusion as previously thought. The actual rotation, during which the nanorod transits from one immobilized state to the other, slows down by 50 times. The second part of the research is the collaboration with Tour's group in Rice University. The ultimate goal is to use light to drive a motorized nanocar at ambient conditions. To fulfill this goal, we first studied the moving kinetics of adamantane-wheeled nanocars on hydroxylated and PEG-modified surfaces using single molecule fluorescence microscopy. We found that nanocars' diffusion slows down on solid surface over time, which is possibly caused by the increased hydrophobicity of the substrate surface due to the adsorbates from the air. A sticky-spots model was proposed to explain the observed slowing down. To find out whether a light-activatable motor works when it is incorporated into a nanocar, we carefully designed a series of molecules containing a regular motor, a slow motor, a nonunidirectional motor, and no motor. We found that a fast unidirectional rotating motor enhanced the diffusion of the molecule in solution upon UV-illumination. Detailed analysis suggested that the unimolecular submersible nanomachine (USN) will give 9-nm step upon each motor actuation. This is the first nanomachine that gives mechanical motion at small molecular scale.
Nucleoplasmic viscosity of living cells investigated by fluorescence correlation spectroscopy

NASA Astrophysics Data System (ADS)

Liang, Lifang; Xing, Da; Chen, Tongshen; Pei, Yihui

2007-11-01

Fluorescence correlation spectroscopy (FCS) is a new kind of real-time, high-speed and single-molecule technique. It is used to detect the kinetic characteristics of fluorescent dye such as diffusion coefficient in the aqueous solution. Combined with confocal microscope optics, it has been now widely applied in cell biological research. Through a time correlation analysis of spontaneous intensity fluctuations, this technique with EGFP as a probe is capable of determining viscosity of fluids according to Stokes-Einstein equation. Nucleoplasmic viscosity is an important physical parameter to quantify the rheological characteristics of the nucleoplasm. Investigation on nucleoplasmic viscosity plays an important role in further understanding intranuclear environment. In this paper, FCS is introduced to noninvasively investigate nucleoplasmic viscosity of living cells. The results show that nucleoplasmic viscosity of lung adenocarcinoma (ASTC-a-1) cells is 2.55+/-0.61 cP and nucleoplasmic viscosity is larger than cytoplasmic viscosity at 37 °C (pH 7.4). In addition, significant changes in nucleoplasmic viscosity are detected by FCS when cells are exposed to hyper or hypotonic medium. Our study suggests that FCS can be used to detect the kinetic characteristics of biomolecules in living cells and thus helps to investigate the dynamic changes of the microenvironment in the cell.
Photolithography and Fluorescence Correlation Spectroscopy used to examine the rates of exchange in reverse micelle systems

NASA Astrophysics Data System (ADS)

Norris, Zach; Mawson, Cara; Johnson, Kyron; Kessler, Sarah; Rebecca, Anne; Wolf, Nathan; Lim, Michael; Nucci, Nathaniel

Reverse micelles are molecular complexes that encapsulate a nanoscale pool of water in a surfactant shell dissolved in non-polar solvent. These complexes have a wide range of applications, and in all cases, the degree to which reverse micelles (RM) exchange their contents is relevant for their use. Despite its importance, this aspect of RM behavior is poorly understood. Photolithography is employed here to create micro and nano scale fluidic systems in which mixing rates can be precisely measured using fluorescence correlation spectroscopy (FCS). Micro-channel patterns are etched using reactive ion etching process into a layer of silicon dioxide on crystalline silicon substrates. Solutions containing mixtures of reverse micelles, proteins, and fluorophores are placed into reservoirs in the patterns, while diffusion and exchange between RMs is monitored using a FCS system built from a modified confocal Raman spectrometer. Using this approach, the diffusion and exchange rates for RM systems are measured as a function of the components of the RM mixture. Funding provided by Rowan University.
Defining the Subcellular Interface of Nanoparticles by Live-Cell Imaging

PubMed Central

Hemmerich, Peter H.; von Mikecz, Anna H.

2013-01-01

Understanding of nanoparticle-bio-interactions within living cells requires knowledge about the dynamic behavior of nanomaterials during their cellular uptake, intracellular traffic and mutual reactions with cell organelles. Here, we introduce a protocol of combined kinetic imaging techniques that enables investigation of exemplary fluorochrome-labelled nanoparticles concerning their intracellular fate. By time-lapse confocal microscopy we observe fast, dynamin-dependent uptake of polystyrene and silica nanoparticles via the cell membrane within seconds. Fluorescence recovery after photobleaching (FRAP) experiments reveal fast and complete exchange of the investigated nanoparticles at mitochondria, cytoplasmic vesicles or the nuclear envelope. Nuclear translocation is observed within minutes by free diffusion and active transport. Fluorescence correlation spectroscopy (FCS) and raster image correlation spectroscopy (RICS) indicate diffusion coefficients of polystyrene and silica nanoparticles in the nucleus and the cytoplasm that are consistent with particle motion in living cells based on diffusion. Determination of the apparent hydrodynamic radii by FCS and RICS shows that nanoparticles exert their cytoplasmic and nuclear effects mainly as mobile, monodisperse entities. Thus, a complete toolkit of fluorescence fluctuation microscopy is presented for the investigation of nanomaterial biophysics in subcellular microenvironments that contributes to develop a framework of intracellular nanoparticle delivery routes. PMID:23637951
A New Scheme for Considering Soil Water-Heat Transport Coupling Based on Community Land Model: Model Description and Preliminary Validation

NASA Astrophysics Data System (ADS)

Wang, Chenghai; Yang, Kai

2018-04-01

Land surface models (LSMs) have developed significantly over the past few decades, with the result that most LSMs can generally reproduce the characteristics of the land surface. However, LSMs fail to reproduce some details of soil water and heat transport during seasonal transition periods because they neglect the effects of interactions between water movement and heat transfer in the soil. Such effects are critical for a complete understanding of water-heat transport within a soil thermohydraulic regime. In this study, a fully coupled water-heat transport scheme (FCS) is incorporated into the Community Land Model (version 4.5) to replaces its original isothermal scheme, which is more complete in theory. Observational data from five sites are used to validate the performance of the FCS. The simulation results at both single-point and global scale show that the FCS improved the simulation of soil moisture and temperature. FCS better reproduced the characteristics of drier and colder surface layers in arid regions by considering the diffusion of soil water vapor, which is a nonnegligible process in soil, especially for soil surface layers, while its effects in cold regions are generally inverse. It also accounted for the sensible heat fluxes caused by liquid water flow, which can contribute to heat transfer in both surface and deep layers. The FCS affects the estimation of surface sensible heat (SH) and latent heat (LH) and provides the details of soil heat and water transportation, which benefits to understand the inner physical process of soil water-heat migration.
Diffusion of lipids and GPI-anchored proteins in actin-free plasma membrane vesicles measured by STED-FCS.

PubMed

Schneider, Falk; Waithe, Dominic; Clausen, Mathias P; Galiani, Silvia; Koller, Thomas; Ozhan, Gunes; Eggeling, Christian; Sezgin, Erdinc

2017-06-01

Diffusion and interaction dynamics of molecules at the plasma membrane play an important role in cellular signaling and are suggested to be strongly associated with the actin cytoskeleton. Here we use superresolution STED microscopy combined with fluorescence correlation spectroscopy (STED-FCS) to access and compare the diffusion characteristics of fluorescent lipid analogues and GPI-anchored proteins (GPI-APs) in the live-cell plasma membrane and in actin cytoskeleton-free, cell-derived giant plasma membrane vesicles (GPMVs). Hindered diffusion of phospholipids and sphingolipids is abolished in the GPMVs, whereas transient nanodomain incorporation of ganglioside lipid GM1 is apparent in both the live-cell membrane and GPMVs. For GPI-APs, we detect two molecular pools in living cells; one pool shows high mobility with transient incorporation into nanodomains, and the other pool forms immobile clusters, both of which disappear in GPMVs. Our data underline the crucial role of the actin cortex in maintaining hindered diffusion modes of many but not all of the membrane molecules and highlight a powerful experimental approach to decipher specific influences on molecular plasma membrane dynamics. © 2017 Schneider et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).
New fluorescence correlation spectroscopy enabling direct observation of spatiotemporal dependence of diffusion constants as an evidence of anomalous transport in extracellular matrices.

PubMed

Masuda, Akiko; Ushida, Kiminori; Okamoto, Takayuki

2005-05-01

The potential of fluorescence correlation spectroscopy (FCS) is extended to enable the direct observation of anomalous subdiffusion (ASD) in inhomogeneous media that are of great importance particularly in many biological systems, such as membranes, cytoplasm, and extracellular matrices (ECMs). Because ASD can be confirmed by monitoring the spatiotemporal dependence of observable diffusion coefficients (D(obs)), the size of the effective confocal volume (V(eff)) for FCS sampling (sampling volume) was continuously changed on a scale of 300-500 nm using a motorized variable beam expander through which an illuminating laser beam passes. This new method, namely, sampling-volume-controlled (SVC)-FCS, was applied to the analysis of hyaluronan (HA) aqueous solutions where the D(obs) of light-emitting solute (Alexa 488) markedly changed, corresponding to the change in V(eff) (220-340 nm in the half-axis), because the network structure of HA of 7-33 nm (nanostructure) interferes with the material transport within it. The results indicate that moderate ASD may occur even in the presence of a small amount ( approximately 0.1 wt %) of HA in ECM. Because the change in D(obs) along with the traveling distance (the mean-square displacement) can be identified even in systems with no deformation of the autocorrelation function, this technique has a great potential for general applications to many biological systems in which ASD shows complex time and space dependences.
Physiological Environment Induces Quick Response – Slow Exhaustion Reactions

PubMed Central

Hiroi, Noriko; Lu, James; Iba, Keisuke; Tabira, Akito; Yamashita, Shuji; Okada, Yasunori; Flamm, Christoph; Oka, Kotaro; Köhler, Gottfried; Funahashi, Akira

2011-01-01

In vivo environments are highly crowded and inhomogeneous, which may affect reaction processes in cells. In this study we examined the effects of intracellular crowding and an inhomogeneity on the behavior of in vivo reactions by calculating the spectral dimension (ds), which can be translated into the reaction rate function. We compared estimates of anomaly parameters obtained from fluorescence correlation spectroscopy (FCS) data with fractal dimensions derived from transmission electron microscopy (TEM) image analysis. FCS analysis indicated that the anomalous property was linked to physiological structure. Subsequent TEM analysis provided an in vivo illustration; soluble molecules likely percolate between intracellular clusters, which are constructed in a self-organizing manner. We estimated a cytoplasmic spectral dimension ds to be 1.39 ± 0.084. This result suggests that in vivo reactions initially run faster than the same reactions in a homogeneous space; this conclusion is consistent with the anomalous character indicated by FCS analysis. We further showed that these results were compatible with our Monte-Carlo simulation in which the anomalous behavior of mobile molecules correlates with the intracellular environment, leading to description as a percolation cluster, as demonstrated using TEM analysis. We confirmed by the simulation that the above-mentioned in vivo like properties are different from those of homogeneously concentrated environments. Additionally, simulation results indicated that crowding level of an environment might affect diffusion rate of reactant. Such knowledge of the spatial information enables us to construct realistic models for in vivo diffusion and reaction systems. PMID:21960972
Fluorescence Correlation Spectroscopy to find the critical balance between extracellular association and intracellular dissociation of mRNA-complexes.

PubMed

Zhang, Heyang; De Smedt, Stefaan C; Remaut, Katrien

2018-05-10

Fluorescence Correlation Spectroscopy (FCS) is a promising tool to study interactions on a single molecule level. The diffusion of fluorescent molecules in and out of the excitation volume of a confocal microscope leads to the fluorescence fluctuations that give information on the average number of fluorescent molecules present in the excitation volume and their diffusion coefficients. In this context, we complexed mRNA into lipoplexes and polyplexes and explored the association/dissociation degree of complexes by using gel electrophoresis and FCS. FCS enabled us to measure the association and dissociation degree of mRNA-based complexes both in buffer and protein-rich biological fluids such as human serum and ascitic fluid, which is a clear advantage over gel electrophoresis that was only applicable in protein-free buffer solutions. Furthermore, following the complex stability in buffer and biological fluids by FCS assisted to understand how complex characteristics, such as charge ratio and strength of mRNA binding, correlated to the transfection efficiency. We found that linear polyethyleneimine prevented efficient translation of mRNA, most likely due to a too strong mRNA binding, whereas the lipid based carrier Lipofectamine ® messengerMAX did succeed in efficient release and subsequent translation of mRNA in the cytoplasm of the cells. Overall, FCS is a reliable tool for the in depth characterization of mRNA complexes and can help us to find the critical balance keeping mRNA bound in complexes in the extracellular environment and efficient intracellular mRNA release leading to protein production. The delivery of messenger RNA (mRNA) to cells is promising to treat a variety of diseases. Therefore, the mRNA is typically packed in small lipid particles or polymer particles that help the mRNA to reach the cytoplasm of the cells. These particles should bind and carry the mRNA in the extracellular environment (e.g. blood, peritoneal fluid, ...), but should release the mRNA again in the intracellular environment. In this paper, we evaluated a method (Fluorescence Correlation Spectroscopy) that allows for the in depth characterization of mRNA complexes and can help us to find the critical balance keeping mRNA bound in complexes in the extracellular environment and efficient intracellular mRNA release leading to protein production. Copyright © 2018. Published by Elsevier Ltd.
Time-resolved fluorescence and FCS studies of dye-doped DNA

NASA Astrophysics Data System (ADS)

Nicolaou, N.; Marsh, R. J.; Blacker, T.; Armoogum, D. A.; Bain, A. J.

2009-08-01

Fluorescence lifetime, anisotropy and intensity dependent single molecule fluorescence correlation spectroscopy (I-FCS) are used to investigate the mechanism of fluorescence saturation in a free and nucleotide bound fluorophore (NR6104) in an antioxidising ascorbate buffer. Nucleotide attachment does not appreciably affect the fluorescence lifetime of the probe and there is a decrease in the rate of intersystem crossing relative to that of triplet state deactivation. The triplet state fraction is seen to plateau at 72% (G-attached) and 80% (free fluorophore) in agreement with these observations. Measurements of translational diffusion times show no intensity dependence for excitation intensities between 1 and 105kW cm-2 and photobleaching is therefore negligible. The dominant mechanism of fluorescence saturation is thus triplet state formation. I-FCS measurements for Rhodamine 6G in water were compared with those in the ascorbate buffer. In water the triplet fraction was saturated at considerably higher powers (45% at ca. 1.5 × 103kW cm-2) than in the ascorbate buffer (55%ca. 1 1kW cm-2)
Phospholipid lateral diffusion in phosphatidylcholine-sphingomyelin-cholesterol monolayers; effects of oxidatively truncated phosphatidylcholines.

PubMed

Parkkila, Petteri; Stefl, Martin; Olżyńska, Agnieszka; Hof, Martin; Kinnunen, Paavo K J

2015-01-01

Oxidative stress is involved in a number of pathological conditions and the generated oxidatively modified lipids influence membrane properties and functions, including lipid-protein interactions and cellular signaling. Brewster angle microscopy demonstrated oxidatively truncated phosphatidylcholines to promote phase separation in monolayers of 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphocholine (POPC), sphingomyelin (SM) and cholesterol (Chol). More specifically, 1-palmitoyl-2-azelaoyl-sn-glycero-3-phosphocholine (PazePC), was found to increase the miscibility transition pressure of the SM/Chol-phase. Lateral diffusion of lipids is influenced by a variety of membrane properties, thus making it a sensitive parameter to observe the coexistence of different lipid phases, for instance. The dependence on lipid lateral packing of the lateral diffusion of fluorophore-containing phospholipid analogs was investigated in Langmuir monolayers composed of POPC, SM, and Chol and additionally containing oxidatively truncated phosphatidylcholines, using fluorescence correlation spectroscopy (FCS). To our knowledge, these are the first FCS results on miscibility transition in ternary lipid monolayers, confirming previous results obtained using Brewster angle microscopy on such lipid monolayers. Wide-field fluorescence microscopy was additionally employed to verify the transition, i.e. the loss and reformation of SM/Chol domains. Copyright © 2014. Published by Elsevier B.V.
Revealing the Effects of Nanoscale Membrane Curvature on Lipid Mobility.

PubMed

Kabbani, Abir Maarouf; Woodward, Xinxin; Kelly, Christopher V

2017-10-18

Recent advances in nanoengineering and super-resolution microscopy have enabled new capabilities for creating and observing membrane curvature. However, the effects of curvature on single-lipid diffusion have yet to be revealed. The simulations presented here describe the capabilities of varying experimental methods for revealing the effects of nanoscale curvature on single-molecule mobility. Traditionally, lipid mobility is revealed through fluorescence recovery after photobleaching (FRAP), fluorescence correlation spectroscopy (FCS), and single particle tracking (SPT). However, these techniques vary greatly in their ability to detect the effects of nanoscale curvature on lipid behavior. Traditionally, FRAP and FCS depend on diffraction-limited illumination and detection. A simulation of FRAP shows minimal effects on lipids diffusion due to a 50 nm radius membrane bud. Throughout the stages of the budding process, FRAP detected minimal changes in lipid recovery time due to the curvature versus flat membrane. Simulated FCS demonstrated small effects due to a 50 nm radius membrane bud that was more apparent with curvature-dependent lipid mobility changes. However, SPT achieves a sub-diffraction-limited resolution of membrane budding and lipid mobility through the identification of the single-lipid positions with ≤15 nm spatial and ≤20 ms temporal resolution. By mapping the single-lipid step lengths to locations on the membrane, the effects of membrane topography and curvature could be correlated to the effective membrane viscosity. Single-fluorophore localization techniques, such SPT, can detect membrane curvature and its effects on lipid behavior. These simulations and discussion provide a guideline for optimizing the experimental procedures in revealing the effects of curvature on lipid mobility and effective local membrane viscosity.
Super-resolution study of polymer mobility fluctuations near c*.

PubMed

King, John T; Yu, Changqian; Wilson, William L; Granick, Steve

2014-09-23

Nanoscale dynamic heterogeneities in synthetic polymer solutions are detected using super-resolution optical microscopy. To this end, we map concentration fluctuations in polystyrene-toluene solutions with spatial resolution below the diffraction limit, focusing on critical fluctuations near the polymer overlap concentration, c*. Two-photon super-resolution microscopy was adapted to be applicable in an organic solvent, and a home-built STED-FCS system with stimulated emission depletion (STED) was used to perform fluorescence correlation spectroscopy (FCS). The polystyrene serving as the tracer probe (670 kg mol(-1), radius of gyration RG ≈ 35 nm, end-labeled with a bodipy derivative chromophore) was dissolved in toluene at room temperature (good solvent) and mixed with matrix polystyrene (3,840 kg mol(-1), RG ≈ 97 nm, Mw/Mn = 1.04) whose concentration was varied from dilute to more than 10c*. Whereas for dilute solutions the intensity-intensity correlation function follows a single diffusion process, it splits starting at c* to imply an additional relaxation process provided that the experimental focal area does not greatly exceed the polymer blob size. We identify the slower mode as self-diffusion and the increasingly rapid mode as correlated segment fluctuations that reflect the cooperative diffusion coefficient, Dcoop. These real-space measurements find quantitative agreement between correlation lengths inferred from dynamic measurements and those from determining the limit below which diffusion coefficients are independent of spot size. This study is considered to illustrate the potential of importing into polymer science the techniques of super-resolution imaging.
FLIM and FCS detection in laser-scanning microscopes: increased efficiency by GaAsP hybrid detectors.

PubMed

Becker, W; Su, B; Holub, O; Weisshart, K

2011-09-01

Photon counting detectors currently used in fluorescence lifetime microscopy have a number of deficiencies that result in less-than-ideal signal-to-noise ratio of the lifetimes obtained: either the quantum efficiency is unsatisfactory or the active area is too small, and afterpulsing or tails in the temporal response contribute to overall timing inaccuracy. We have therefore developed a new FLIM detector based on a GaAsP hybrid photomultiplier. Compared with conventional PMTs and SPADs, GaAsP hybrid detectors have a number of advantages: The detection quantum efficiency reaches or surpasses the efficiency of fast SPADs, and the active area is on the order of 5 mm², compared with 2.5 10⁻³ mm² for a SPAD. The TCSPC response is clean, without the bumps and the diffusion tails typical for PMTs and SPADs. Most important, the hybrid detector is intrinsically free of afterpulsing. FLIM results are therefore free of signal-dependent background, and FCS curves are free of the known afterpulsing peak. We demonstrate the performance of the new detector for multiphoton NDD FLIM and for FCS. Copyright © 2010 Wiley-Liss, Inc.
Exploring doxorubicin localization in eluting TiO2 nanotube arrays through fluorescence correlation spectroscopy analysis.

PubMed

De Santo, Ilaria; Sanguigno, Luigi; Causa, Filippo; Monetta, Tullio; Netti, Paolo A

2012-11-07

Drug elution properties of TiO(2) nanotube arrays have been largely investigated by means of solely macroscopic observations. Controversial elution performances have been reported so far and a clear comprehension of these phenomena is still missing as a consequence of a lack of molecular investigation methods. Here we propose a way to discern drug elution properties of nanotubes through the evaluation of drug localization by Fluorescence Correlation Spectroscopy (FCS) analysis. We verified this method upon doxorubicin elution from differently loaded TiO(2) nanotubes. Diverse elution profiles were obtained from nanotubes filled by soaking and wet vacuum impregnation methods. Impregnated nanotubes controlled drug diffusion up to thirty days, while soaked samples completed elution in seven days. FCS analysis of doxorubicin motion in loaded nanotubes clarified that more than 90% of drugs dwell preferentially in inter-nanotube spaces in soaked samples due to decorrelation in a 2D fashion, while a 97% fraction of molecules showed 1D mobility ascribable to displacements along the nanotube vertical axis of wet vacuum impregnated nanotubes. The diverse drug localizations inferred from FCS measurements, together with distinct drug-surface interaction strengths resulting from diverse drug filling techniques, could explain the variability in elution kinetics.
In-Flight Suppression of an Unstable F/A-18 Structural Mode Using the Space Launch System Adaptive Augmenting Control System

NASA Technical Reports Server (NTRS)

VanZwieten, Tannen S.; Gilligan, Eric T.; Wall, John H.; Miller, Christopher J.; Hanson, Curtis E.; Orr, Jeb S.

2015-01-01

NASA's Space Launch System (SLS) Flight Control System (FCS) includes an Adaptive Augmenting Control (AAC) component which employs a multiplicative gain update law to enhance the performance and robustness of the baseline control system for extreme off-nominal scenarios. The SLS FCS algorithm including AAC has been flight tested utilizing a specially outfitted F/A-18 fighter jet in which the pitch axis control of the aircraft was performed by a Non-linear Dynamic Inversion (NDI) controller, SLS reference models, and the SLS flight software prototype. This paper describes test cases from the research flight campaign in which the fundamental F/A-18 airframe structural mode was identified using post-flight frequency-domain reconstruction, amplified to result in closed loop instability, and suppressed in-flight by the SLS adaptive control system.

Revealing the Effects of Nanoscale Membrane Curvature on Lipid Mobility

PubMed Central

Kabbani, Abir Maarouf; Woodward, Xinxin

2017-01-01

Recent advances in nanoengineering and super-resolution microscopy have enabled new capabilities for creating and observing membrane curvature. However, the effects of curvature on single-lipid diffusion have yet to be revealed. The simulations presented here describe the capabilities of varying experimental methods for revealing the effects of nanoscale curvature on single-molecule mobility. Traditionally, lipid mobility is revealed through fluorescence recovery after photobleaching (FRAP), fluorescence correlation spectroscopy (FCS), and single particle tracking (SPT). However, these techniques vary greatly in their ability to detect the effects of nanoscale curvature on lipid behavior. Traditionally, FRAP and FCS depend on diffraction-limited illumination and detection. A simulation of FRAP shows minimal effects on lipids diffusion due to a 50 nm radius membrane bud. Throughout the stages of the budding process, FRAP detected minimal changes in lipid recovery time due to the curvature versus flat membrane. Simulated FCS demonstrated small effects due to a 50 nm radius membrane bud that was more apparent with curvature-dependent lipid mobility changes. However, SPT achieves a sub-diffraction-limited resolution of membrane budding and lipid mobility through the identification of the single-lipid positions with ≤15 nm spatial and ≤20 ms temporal resolution. By mapping the single-lipid step lengths to locations on the membrane, the effects of membrane topography and curvature could be correlated to the effective membrane viscosity. Single-fluorophore localization techniques, such SPT, can detect membrane curvature and its effects on lipid behavior. These simulations and discussion provide a guideline for optimizing the experimental procedures in revealing the effects of curvature on lipid mobility and effective local membrane viscosity. PMID:29057801
Fluorescence correlation spectroscopy to measure the metabolism of high-density lipoprotein

NASA Astrophysics Data System (ADS)

Deitrick, Russell; Gibson, Emily; Razzaghi, Hamid

2009-10-01

High-density lipoprotein (HDL), referred to as the ``good cholesterol'', carries free cholesterol to the liver to be filtered from the bloodstream and is important to our understanding of atherosclerosis. HDL is metabolized in part by the enzyme Endothelial Lipase (EL). With this project we will use fluorescence correlation spectroscopy (FCS) to study the metabolism of HDL by EL comparing wild type with different genetic mutations. FCS is an advanced microscopy technique in which we record fluctuations in the fluorescence of dye-labeled molecules (in this case, HDL labeled with Nile Red) as they freely diffuse through a small focal volume. This data can be analyzed mathematically using the cross-correlation function, from which we can ultimately ascertain much information. In our case, we are interested in the diffusion coefficient which, via the Stokes-Einstein relation for a sphere, we can determine the size of HDL as it undergoes the process of metabolism. Preliminary results seem to indicate that the metabolic process occurs very quickly, that the final size of HDL depends primarily on the concentration of EL, and that the wild and mutant variants of EL have a similar effectiveness. In following experiments, we hope to investigate these relationships further.
Position-sensitive scanning fluorescence correlation spectroscopy.

PubMed

Skinner, Joseph P; Chen, Yan; Müller, Joachim D

2005-08-01

Fluorescence correlation spectroscopy (FCS) uses a stationary laser beam to illuminate a small sample volume and analyze the temporal behavior of the fluorescence fluctuations within the stationary observation volume. In contrast, scanning FCS (SFCS) collects the fluorescence signal from a moving observation volume by scanning the laser beam. The fluctuations now contain both temporal and spatial information about the sample. To access the spatial information we synchronize scanning and data acquisition. Synchronization allows us to evaluate correlations for every position along the scanned trajectory. We use a circular scan trajectory in this study. Because the scan radius is constant, the phase angle is sufficient to characterize the position of the beam. We introduce position-sensitive SFCS (PSFCS), where correlations are calculated as a function of lag time and phase. We present the theory of PSFCS and derive expressions for diffusion, diffusion in the presence of flow, and for immobilization. To test PSFCS we compare experimental data with theory. We determine the direction and speed of a flowing dye solution and the position of an immobilized particle. To demonstrate the feasibility of the technique for applications in living cells we present data of enhanced green fluorescent protein measured in the nucleus of COS cells.
In-Flight Suppression of a Destabilized F/A-18 Structural Mode Using the Space Launch System Adaptive Augmenting Control System

NASA Technical Reports Server (NTRS)

Wall, John H.; VanZwieten, Tannen S.; Gilligan, Eric T.; Miller, Christopher J.; Hanson, Curtis E.; Orr, Jeb S.

2015-01-01

NASA's Space Launch System (SLS) Flight Control System (FCS) includes an Adaptive Augmenting Control (AAC) component which employs a multiplicative gain update law to enhance the performance and robustness of the baseline control system for extreme off nominal scenarios. The SLS FCS algorithm including AAC has been flight tested utilizing a specially outfitted F/A-18 fighter jet in which the pitch axis control of the aircraft was performed by a Non-linear Dynamic Inversion (NDI) controller, SLS reference models, and the SLS flight software prototype. This paper describes test cases from the research flight campaign in which the fundamental F/A-18 airframe structural mode was identified using frequency-domain reconstruction of flight data, amplified to result in closed loop instability, and suppressed in-flight by the SLS adaptive control system.
Ultrasensitive protein detection in blood serum using gold nanoparticle probes by single molecule spectroscopy

NASA Astrophysics Data System (ADS)

Chen, Jiji; Wang, Chungang; Irudayaraj, Joseph

2009-07-01

A one-step rapid and ultrasensitive immunoassay capable of detecting proteins in blood serum is developed using gold nanoprobes and fluorescence correlation spectroscopy (FCS). In this approach we take advantage of the inherent photoluminescence property of gold nanoparticles (GNPs) to develop a fluorophore-free assay to observe binding entities by monitoring the diffusion of bound versus unbound molecules in a limited confocal volume. 40-nm GNPs conjugated separately with rabbit anti-IgG (Fc) and goat anti-IgG (Fab) when incubated in blood serum containing IgG forms a sandwich structure constituting dimers and oligomers that can be differentiated by to detect IgG in blood serum at a limit of detection (LOD) of 5 pg/ml. The novelty of integrating GNPs with FCS to develop a sensitive blood immunoassay brings single molecule methods one step closer to the clinic.
Molecular dynamics in an optical trap of glutamate receptors labeled with quantum-dots on living neurons

NASA Astrophysics Data System (ADS)

Kishimoto, Tatsunori; Maezawa, Yasuyo; Kudoh, Suguru N.; Taguchi, Takahisa; Hosokawa, Chie

2017-04-01

Molecular dynamics of glutamate receptor, which is major neurotransmitter receptor at excitatory synapse located on neuron, is essential for synaptic plasticity in the complex neuronal networks. Here we studied molecular dynamics in an optical trap of AMPA-type glutamate receptor (AMPAR) labeled with quantum-dot (QD) on living neuronal cells with fluorescence imaging and fluorescence correlation spectroscopy (FCS). When a 1064-nm laser beam for optical trapping was focused on QD-AMPARs located on neuronal cells, the fluorescence intensity of QD-AMPARs gradually increased at the focal spot. Using single-particle tracking of QD-AMPARs on neurons, the average diffusion coefficient decreased in an optical trap. Moreover, the decay time obtained from FCS analysis increased with the laser power and the initial assembling state of AMPARs depended on culturing day, suggesting that the motion of QD-AMPAR was constrained in an optical trap.
Stochastic approach to data analysis in fluorescence correlation spectroscopy.

PubMed

Rao, Ramachandra; Langoju, Rajesh; Gösch, Michael; Rigler, Per; Serov, Alexandre; Lasser, Theo

2006-09-21

Fluorescence correlation spectroscopy (FCS) has emerged as a powerful technique for measuring low concentrations of fluorescent molecules and their diffusion constants. In FCS, the experimental data is conventionally fit using standard local search techniques, for example, the Marquardt-Levenberg (ML) algorithm. A prerequisite for these categories of algorithms is the sound knowledge of the behavior of fit parameters and in most cases good initial guesses for accurate fitting, otherwise leading to fitting artifacts. For known fit models and with user experience about the behavior of fit parameters, these local search algorithms work extremely well. However, for heterogeneous systems or where automated data analysis is a prerequisite, there is a need to apply a procedure, which treats FCS data fitting as a black box and generates reliable fit parameters with accuracy for the chosen model in hand. We present a computational approach to analyze FCS data by means of a stochastic algorithm for global search called PGSL, an acronym for Probabilistic Global Search Lausanne. This algorithm does not require any initial guesses and does the fitting in terms of searching for solutions by global sampling. It is flexible as well as computationally faster at the same time for multiparameter evaluations. We present the performance study of PGSL for two-component with triplet fits. The statistical study and the goodness of fit criterion for PGSL are also presented. The robustness of PGSL on noisy experimental data for parameter estimation is also verified. We further extend the scope of PGSL by a hybrid analysis wherein the output of PGSL is fed as initial guesses to ML. Reliability studies show that PGSL and the hybrid combination of both perform better than ML for various thresholds of the mean-squared error (MSE).
Ionic liquid induced dehydration and domain closure in lysozyme: FCS and MD simulation

NASA Astrophysics Data System (ADS)

Ghosh, Shirsendu; Parui, Sridip; Jana, Biman; Bhattacharyya, Kankan

2015-09-01

Effect of a room temperature ionic liquid (RTIL, [pmim][Br]) on the structure and dynamics of the protein, lysozyme, is investigated by fluorescence correlation spectroscopy (FCS) and molecular dynamic (MD) simulation. The FCS data indicate that addition of the RTIL ([pmim][Br]) leads to reduction in size and faster conformational dynamics of the protein. The hydrodynamic radius (rH) of lysozyme decreases from 18 Å in 0 M [pmim][Br] to 11 Å in 1.5 M [pmim][Br] while the conformational relaxation time decreases from 65 μs to 5 μs. Molecular origin of the collapse (size reduction) of lysozyme in aqueous RTIL is analyzed by MD simulation. The radial distribution function of water, RTIL cation, and RTIL anion from protein clearly indicates that addition of RTIL causes replacement of interfacial water by RTIL cation ([pmim]+) from the first solvation layer of the protein providing a comparatively dehydrated environment. This preferential solvation of the protein by the RTIL cation extends up to ˜30 Å from the protein surface giving rise to a nanoscopic cage of overall radius 42 Å. In the nanoscopic cage of the RTIL (42 Å), volume fraction of the protein (radius 12 Å) is only about 2%. RTIL anion does not show any preferential solvation near protein surface. Comparison of effective radius obtained from simulation and from FCS data suggests that the "dry" protein (radius 12 Å) alone diffuses in a nanoscopic cage of RTIL (radius 42 Å). MD simulation further reveals a decrease in distance ("domain closure") between the two domains (alpha and beta) of the protein leading to a more compact structure compared to that in the native state.
Ionic liquid induced dehydration and domain closure in lysozyme: FCS and MD simulation.

PubMed

Ghosh, Shirsendu; Parui, Sridip; Jana, Biman; Bhattacharyya, Kankan

2015-09-28

Effect of a room temperature ionic liquid (RTIL, [pmim][Br]) on the structure and dynamics of the protein, lysozyme, is investigated by fluorescence correlation spectroscopy (FCS) and molecular dynamic (MD) simulation. The FCS data indicate that addition of the RTIL ([pmim][Br]) leads to reduction in size and faster conformational dynamics of the protein. The hydrodynamic radius (rH) of lysozyme decreases from 18 Å in 0 M [pmim][Br] to 11 Å in 1.5 M [pmim][Br] while the conformational relaxation time decreases from 65 μs to 5 μs. Molecular origin of the collapse (size reduction) of lysozyme in aqueous RTIL is analyzed by MD simulation. The radial distribution function of water, RTIL cation, and RTIL anion from protein clearly indicates that addition of RTIL causes replacement of interfacial water by RTIL cation ([pmim](+)) from the first solvation layer of the protein providing a comparatively dehydrated environment. This preferential solvation of the protein by the RTIL cation extends up to ∼30 Å from the protein surface giving rise to a nanoscopic cage of overall radius 42 Å. In the nanoscopic cage of the RTIL (42 Å), volume fraction of the protein (radius 12 Å) is only about 2%. RTIL anion does not show any preferential solvation near protein surface. Comparison of effective radius obtained from simulation and from FCS data suggests that the "dry" protein (radius 12 Å) alone diffuses in a nanoscopic cage of RTIL (radius 42 Å). MD simulation further reveals a decrease in distance ("domain closure") between the two domains (alpha and beta) of the protein leading to a more compact structure compared to that in the native state.
Anomalous transport in the crowded world of biological cells

NASA Astrophysics Data System (ADS)

Höfling, Felix; Franosch, Thomas

2013-04-01

A ubiquitous observation in cell biology is that the diffusive motion of macromolecules and organelles is anomalous, and a description simply based on the conventional diffusion equation with diffusion constants measured in dilute solution fails. This is commonly attributed to macromolecular crowding in the interior of cells and in cellular membranes, summarizing their densely packed and heterogeneous structures. The most familiar phenomenon is a sublinear, power-law increase of the mean-square displacement (MSD) as a function of the lag time, but there are other manifestations like strongly reduced and time-dependent diffusion coefficients, persistent correlations in time, non-Gaussian distributions of spatial displacements, heterogeneous diffusion and a fraction of immobile particles. After a general introduction to the statistical description of slow, anomalous transport, we summarize some widely used theoretical models: Gaussian models like fractional Brownian motion and Langevin equations for visco-elastic media, the continuous-time random walk model, and the Lorentz model describing obstructed transport in a heterogeneous environment. Particular emphasis is put on the spatio-temporal properties of the transport in terms of two-point correlation functions, dynamic scaling behaviour, and how the models are distinguished by their propagators even if the MSDs are identical. Then, we review the theory underlying commonly applied experimental techniques in the presence of anomalous transport like single-particle tracking, fluorescence correlation spectroscopy (FCS) and fluorescence recovery after photobleaching (FRAP). We report on the large body of recent experimental evidence for anomalous transport in crowded biological media: in cyto- and nucleoplasm as well as in cellular membranes, complemented by in vitro experiments where a variety of model systems mimic physiological crowding conditions. Finally, computer simulations are discussed which play an important role in testing the theoretical models and corroborating the experimental findings. The review is completed by a synthesis of the theoretical and experimental progress identifying open questions for future investigation.
Modeling, Materials, and Metrics: The Three-m Approach to FCS Signature Solutions

DTIC Science & Technology

2002-05-07

calculations. These multiple levels will be incorporated into the MuSES software. The four levels are described as follows: "* Radiosity - Deterministic...view-factor-based, all-diffuse solution. Very fast. Independent of user position. "* Directional Reflectivity - Radiosity with directional incident...target and environment facets (view factor with BRDF). Last ray cast bounce = radiosity solution. "* Multi-bounce path trace - Rays traced from observer
Electrochemical investigation of stainless steel corrosion in a proton exchange membrane electrolyzer cell

DOE PAGES

Mo, Jingke; Steen, Stuart M.; Zhang, Feng-Yuan; ...

2015-08-05

The lack of a fundamental understanding of the corrosion mechanisms in the electrochemical environments of proton exchange membrane (PEM) electrolyzer and/or fuel cells (ECs/FCs) has seriously hindered the improvement of performance and efficiency of PEM ECs/FCs. In this study, a stainless steel mesh was purposely used as an anode gas diffusion layer that was intentionally operated with high positive potentials under harsh oxidative environments in a PEMEC to study the corrosion mechanism of metal migration. A significant amount of iron and nickel cations were determined to transport through the anode catalyst layer, the PEM and the cathode catalyst layer duringmore » the PEMEC operation. The formation/deposition of iron oxide and nickel oxide on the carbon paper gas diffusion layer at the cathode side is first revealed by both scanning electron microscope and X-ray diffraction. The results indicate the corrosion elements of iron and nickel are transported from anode to cathode through the catalyst-coated membrane, and deposited on carbon fibers as oxides. This phenomenon could also open a new corrosion-based processing approach to potentially fabricate multifunctional oxide structures on carbon fiber devices. This study has demonstrated a new accelerated test method for investigating the corrosion and durability of metallic materials as well.« less
Electrochemical investigation of stainless steel corrosion in a proton exchange membrane electrolyzer cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mo, Jingke; Steen, Stuart M.; Zhang, Feng-Yuan

The lack of a fundamental understanding of the corrosion mechanisms in the electrochemical environments of proton exchange membrane (PEM) electrolyzer and/or fuel cells (ECs/FCs) has seriously hindered the improvement of performance and efficiency of PEM ECs/FCs. In this study, a stainless steel mesh was purposely used as an anode gas diffusion layer that was intentionally operated with high positive potentials under harsh oxidative environments in a PEMEC to study the corrosion mechanism of metal migration. A significant amount of iron and nickel cations were determined to transport through the anode catalyst layer, the PEM and the cathode catalyst layer duringmore » the PEMEC operation. The formation/deposition of iron oxide and nickel oxide on the carbon paper gas diffusion layer at the cathode side is first revealed by both scanning electron microscope and X-ray diffraction. The results indicate the corrosion elements of iron and nickel are transported from anode to cathode through the catalyst-coated membrane, and deposited on carbon fibers as oxides. This phenomenon could also open a new corrosion-based processing approach to potentially fabricate multifunctional oxide structures on carbon fiber devices. This study has demonstrated a new accelerated test method for investigating the corrosion and durability of metallic materials as well.« less
Suicidal ideation and suicide attempts in anxious or depressed family caregivers of patients with cancer: a nationwide survey in Korea.

PubMed

Park, Boyoung; Kim, So Young; Shin, Ji-Yeon; Sanson-Fisher, Robert W; Shin, Dong Wook; Cho, Juhee; Park, Jong Hyock

2013-01-01

To describe the prevalence of suicidal ideation and suicide attempts in family caregivers (FCs) of patients with cancer and to identify the factors associated with suicidal ideation and suicide attempts in FCs with anxiety or depression. A national, multicenter survey administered to 897 FCs asked questions concerning suicidal ideation and suicide attempts during the previous year and assessed anxiety, depression, socio-demographic factors, caregiving burden, patient factors, and quality of life (QOL). A total of 17.7% FCs reported suicidal ideation, and 2.8% had attempted suicide during the previous year. Among FCs with anxiety, 31.9% had suicidal ideation and 4.7% attempted suicide; the corresponding values for FCs with depression were 20.4% and 3.3%, respectively. Compared with FCs without anxiety and depression, FCs with anxiety or depression showed a higher adjusted odds ratios (aOR) for suicidal ideation (aOR= 4.07 and 1.93, respectively) and attempts (OR= 3.00 and 2.43, respectively). Among FCs with anxiety or depression, being female, unmarried, unemployed during caregiving, and having a low QOL were associated with increased odds of suicidal ideation. FCs with anxiety who became unemployed during caregiving constituted a high-risk group for suicide. Being unmarried and having a low QOL with respect to financial matters were associated with increased suicide attempts among FCs with depression. FCs with anxiety or depression were at high risk of suicide. Interventions to enhance social support and to improve perceived QOL may help prevent suicide and manage suicidal ideation in FCs with anxiety or depression.
Quality of life, psychological burden, needs, and satisfaction during specialized inpatient palliative care in family caregivers of advanced cancer patients.

PubMed

Ullrich, Anneke; Ascherfeld, Lilian; Marx, Gabriella; Bokemeyer, Carsten; Bergelt, Corinna; Oechsle, Karin

2017-05-10

This pilot study aimed to investigate quality of life, psychological burden, unmet needs, and care satisfaction in family caregivers of advanced cancer patients (FCs) during specialized inpatient palliative care (SIPC) and to test feasibility and acceptance of the questionnaire survey. During a period of 12 weeks, FCs were recruited consecutively within 72 h after the patient's admission. They completed validated scales on several outcomes: quality of life (SF-8), distress (DT), anxiety (GAD-7), depression (PHQ-9), supportive needs (FIN), palliative care outcome (POS), and satisfaction with care (FAMCARE-2). We used non-parametric tests, t-tests and correlation analyses to address our research questions. FCs showed high study commitment: 74 FCs were asked to participate whereof 54 (73%) agreed and 51 (69%) returned the questionnaire. Except for "bodily pain", FCs' quality of life (SF-8) was impaired in all subscales. Most FCs (96%) reported clinically significant own distress (DT), with sadness, sorrows and exhaustion being the most distressing problems (80-83%). Moderate to severe anxiety (GAD-7) and depression (PHQ-9) were prevalent in 43% and 41% of FCs, respectively. FCs scored a mean number of 16.3 of 20 needs (FIN) as very or extremely important (SD 3.3), 20% of needs were unmet in >50% of FCs. The mean POS score assessed by FCs was 16.6 (SD 5.0) and satisfaction (FAMCARE-2) was high (73.4; SD 8.3). This pilot study demonstrated feasibility of the questionnaire survey and showed relevant psychosocial burden and unmet needs in FCs during SIPC. However, FCs' satisfaction with SIPC seemed to be high. A current multicenter study evaluates these findings longitudinally in a large cohort of FCs.
Counting and behavior of an individual fluorescent molecule without hydrodynamic flow, immobilization, or photon count statistics.

PubMed

Földes-Papp, Zeno; Baumann, Gerd; Demel, Ulrike; Tilz, Gernot P

2004-04-01

Many theoretical models of molecular interactions, biochemical and chemical reactions are described on the single-molecule level, although our knowledge about the biochemical/chemical structure and dynamics primarily originates from the investigation of many-molecule systems. At present, there are four experimental platforms to observe the movement and the behavior of single fluorescent molecules: wide-field epi-illumination, near-field optical scanning, and laser scanning confocal and multiphoton microscopy. The platforms are combined with analytical methods such as fluorescence resonance energy transfer (FRET), fluorescence auto-or two-color cross-correlation spectroscopy (FCS), fluorescence polarizing anisotropy, fluorescence quenching and fluorescence lifetime measurements. The original contribution focuses on counting and characterization of freely diffusing single molecules in a single-phase like a solution or a membrane without hydrodynamic flow, immobilization or burst size analysis of intensity traces. This can be achieved, for example, by Fluorescence auto- or two-color cross-Correlation Spectroscopy as demonstrated in this original article. Three criteria (Földes-Papp (2002) Pteridines, 13, 73-82; Földes-Papp et al. (2004a) J. Immunol. Meth., 286, 1-11; Földes-Papp et al. (2004b) J. Immunol. Meth., 286, 13-20) are discussed for performing continuous measurements with one and the same single (individual) molecule, freely diffusing in a solution or a membrane, from sub-milliseconds up to severals hours. The 'algorithms' developed for single-molecule fluorescence detection are called the 'selfsame single-fluorescent-molecule regime'. An interesting application of the results found is in the field of immunology. The application of the theory to experimental results shows that the theory is consistent with the experiments. The exposition of the novel ideas on Single (Solution)-Phase Single-Molecule Fluorescence auto- or two-color cross-Correlation Spectroscopy (SPSM-FCS) are comprehensively presented. As technology continues to improve, the limits of what FCS/FCCS is being asked to do are concomitantly pushed.
Protonation Dynamics on Lipid Nanodiscs: Influence of the Membrane Surface Area and External Buffers.

PubMed

Xu, Lei; Öjemyr, Linda Näsvik; Bergstrand, Jan; Brzezinski, Peter; Widengren, Jerker

2016-05-10

Lipid membrane surfaces can act as proton-collecting antennae, accelerating proton uptake by membrane-bound proton transporters. We investigated this phenomenon in lipid nanodiscs (NDs) at equilibrium on a local scale, analyzing fluorescence fluctuations of individual pH-sensitive fluorophores at the membrane surface by fluorescence correlation spectroscopy (FCS). The protonation rate of the fluorophores was ∼100-fold higher when located at 9- and 12-nm diameter NDs, compared to when in solution, indicating that the proton-collecting antenna effect is maximal already for a membrane area of ∼60 nm(2). Fluorophore-labeled cytochrome c oxidase displayed a similar increase when reconstituted in 12 nm NDs, but not in 9 nm NDs, i.e., an acceleration of the protonation rate at the surface of cytochrome c oxidase is found when the lipid area surrounding the protein is larger than 80 nm(2), but not when below 30 nm(2). We also investigated the effect of external buffers on the fluorophore proton exchange rates at the ND membrane-water interfaces. With increasing buffer concentrations, the proton exchange rates were found to first decrease and then, at millimolar buffer concentrations, to increase. Monte Carlo simulations, based on a simple kinetic model of the proton exchange at the membrane-water interface, and using rate parameter values determined in our FCS experiments, could reconstruct both the observed membrane-size and the external buffer dependence. The FCS data in combination with the simulations indicate that the local proton diffusion coefficient along a membrane is ∼100 times slower than that observed over submillimeter distances by proton-pulse experiments (Ds ∼ 10(-5)cm(2)/s), and support recent theoretical studies showing that proton diffusion along membrane surfaces is time- and length-scale dependent. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.
Fluorescence Correlation Spectroscopy to Study Diffusion of Polymer Chains within Layered Hydrogen-Bonded Polymer Films

NASA Astrophysics Data System (ADS)

Pristinski, Denis; Kharlampieva, Evguenia; Sukhishvili, Svetlana

2002-03-01

Fluorescence Correlation Spectroscopy (FCS) has been used to probe molecular motions within polymer multilayers formed by hydrogen-bonding sequential self-assembly. Polyethylene glycol (PEG) molecules were end-labeled with the fluorescent tags, and self-assembled with polymethacrylic acid (PMAA) using layer-by-layer deposition. We have found that molecules included in the top adsorbed layer have significant mobility at the millisecond time scale, probably due to translational diffusion. However, their dynamics deviate from classical Brownian motion with a single diffusion time. Possible reasons for the deviation are discussed. We found that motions were significantly slowed with increasing depth within the PEG/PMAA multilayer. This phenomena occured in a narrow pH range around 4.0 in which intermolecular interactions were relatively weak.
CytometryML with DICOM and FCS

NASA Astrophysics Data System (ADS)

Leif, Robert C.

2018-02-01

Abstract: Flow Cytometry Standard, FCS, and Digital Imaging and Communications in Medicine standard, DICOM, are based on extensive, superb domain knowledge, However, they are isolated systems, do not take advantage of data structures, require special programs to read and write the data, lack the capability to interoperate or work with other standards and FCS lacks many of the datatypes necessary for clinical laboratory data. The large overlap between imaging and flow cytometry provides strong evidence that both modalities should be covered by the same standard. Method: The XML Schema Definition Language, XSD 1.1 was used to translate FCS and/or DICOM objects. A MIFlowCyt file was tested with published values. Results: Previously, a significant part of an XML standard based upon a combination of FCS and DICOM has been implemented and validated with MIFlowCyt data. Strongly typed translations of FCS keywords have been constructed in XML. These keywords contain links to their DICOM and FCS equivalents.
Confined detection volume of fluorescence correlation spectroscopy by bare fiber probes.

PubMed

Lu, Guowei; Lei, Franck H; Angiboust, Jean-François; Manfait, Michel

2010-04-01

A fiber-tip-based near-field fluorescence correlation spectroscopy (FCS) has been developed for confining the detection volume to sub-diffraction-limited dimensions. This near-field FCS is based on near-field illumination by coupling a scanning near-field optical microscope (SNOM) to a conventional confocal FCS. Single-molecule FCS analysis at 100 nM Rhodamine 6G has been achieved by using bare chemically etched, tapered fiber tips. The detection volume under control of the SNOM system has been reduced over one order of magnitude compared to that of the conventional confocal FCS. Related factors influencing the near-field FCS performance are investigated and discussed in detail. In this proof-of-principle study, the preliminary experimental results suggest that the fiber-tip-based near-field FCS might be a good alternative to realize localized analysis at the single-molecule level.

Reflections on Field Experiences Related to Diversity Issues: Illinois State's Undergrad FCS Teaching Methods Course

ERIC Educational Resources Information Center

Banning, Jennifer

2013-01-01

This study documents what pre-service family and consumer sciences (FCS) teachers learned about diversity through observations in diverse FCS classrooms. Students reported that they experienced a change in their comfort level with diverse settings. Student feedback was used to modify FCS teacher education curriculum in subsequent semesters.
Distance Learning Now an Option: Consortium Tackles FCS Teacher Shortage

ERIC Educational Resources Information Center

Pickard, Mary J.

2005-01-01

In February 2001, national family and consumer sciences (FCS) leaders, state department of education supervisors, and FCS education providers from 16 higher education institutions representing every region of the U.S. met to establish a national support system and clearinghouse for FCS teacher preparation. Their goal was to aid existing FCS…
Analyzing FCS Professionals in Higher Education: A Case Study

ERIC Educational Resources Information Center

Hall, Scott S.; Harden, Amy; Pucciarelli, Deanna L.

2016-01-01

A national study of family and consumer sciences (FCS) professionals in higher education was analyzed as a case study to illustrate procedures useful for investigating issues related to FCS. The authors analyzed response rates of more than 1,900 FCS faculty and administrators by comparing those invited to participate and the 345 individuals who…
Importing super-resolution imaging into nanoscale puzzles of materials dynamics

NASA Astrophysics Data System (ADS)

King, John; Tsang, Chi Hang Boyce; Wilson, William; Granick, Steve

2014-03-01

A limitation of the exciting recent advances in sub-diffraction microscopy is that they focus on imaging rather than dynamical changes. We are engaged in extending this technique beyond the usual biological applications to address materials problems instead. To this end, we employ stimulated emission depletion (STED) microscopy, which relies on selectively turning off fluorescence emitters through stimulated emission, allowing only a small subset of emitters to be detected, such that the excitation spot size can be downsized to tens of nanometers. By coupling the STED excitation scheme to fluorescence correlation spectroscopy (FCS), diffusive processes are studied with nanoscale resolution. Here, we demonstrate the benefits of such experimental capabilities in a diverse range of complex systems, ranging from the diffusion of nano-objects in crowded 3D environments to the study of polymer diffusion on 2D surfaces.
Factors Associated With Caregivers' Resilience in a Terminal Cancer Care Setting.

PubMed

Hwang, In Cheol; Kim, Young Sung; Lee, Yong Joo; Choi, Youn Seon; Hwang, Sun Wook; Kim, Hyo Min; Koh, Su-Jin

2018-04-01

Resilience implies characteristics such as self-efficacy, adaptability to change, optimism, and the ability to recover from traumatic stress. Studies on resilience in family caregivers (FCs) of patients with terminal cancer are rare. This study aims to examine the factors associated with FCs' resilience in a terminal cancer care setting. This is a cross-sectional study of 273 FCs from 7 hospice and palliative care units in Korea. Resilience was categorized as high and low, and factors associated with resilience were grouped or categorized into subscales. A multivariate logistic regression analysis was used to examine relevant factors. High FCs' resilience was significantly associated with FCs' health status, depression, and social support. In a multivariate regression model, FCs' perception of good health (adjusted odds ratio [aOR] = 2.26, 95% confidence interval [CI] = 1.16-4.40), positive social support (aOR = 3.70, 95% CI = 1.07-12.87), and absence of depression (aOR = 3.12, 95% CI = 1.59-6.13) remained significantly associated with high FCs' resilience. Lack of family support is associated with and may be a cause of diminished resilience. And more concern should be paid to FCs to improve FCs' health and emotional status. Education programs might be effective for improving caregivers' resilience. Further research with supportive interventions is indicated.
Cancer diagnosis disclosure preferences of family caregivers of cancer patients in Egypt.

PubMed

Alsirafy, Samy A; Abdel-Kareem, Shady S; Ibrahim, Noha Y; Abolkasem, Mohamed A; Farag, Dina E

2017-11-01

Family caregivers (FCs) of cancer patients are frequently seen as a barrier to honest communication with patients in Egypt. This study was conducted to investigate the attitude of FCs of cancer patients toward cancer diagnosis disclosure (CDD) and its determinants. A structured interview was used to assess the preferences of 288 FCs regarding CDD. According to the FCs, 85% of patients were aware of their diagnosis. The majority (81%) of FCs preferred CDD to patients. In case they developed cancer, 92% of FCs wanted to know their diagnosis and 88% wanted to inform their families. In a univariate analysis, factors associated with FCs' negative attitude toward CDD to patients were as follows: patient's lower level of education (P = .001), patient's rural residence (P < .001), hematological malignancies (P < .001), FC's belief that the patient is unaware of diagnosis (P < .001), FC's unwillingness to know his/her own cancer diagnosis (P < .001), and FC's unwillingness to inform his/her family about his/her cancer diagnosis (P < .001). Only 2 factors predicted independently the negative attitude of FCs toward CDD, the FC's belief that the patient is unaware of diagnosis (P < .001), and the FC's unwillingness to know his/her own cancer diagnosis (P = .049). The results suggest that the majority of FCs of Egyptian cancer patients prefer CDD to patients. The finding that the vast majority of FCs of aware patients preferred CDD suggests that the reaction of Egyptian patients to CDD is acceptable by FCs. Family caregivers with a negative attitude toward CDD may be reflecting their own fears. Copyright © 2016 John Wiley & Sons, Ltd.
Improving Students' Familiarity with the Family and Consumer Sciences Body of Knowledge (FCS-BOK)

ERIC Educational Resources Information Center

Walker, Jane; Williams-Wheeler, Meeshay; Lee, Sung-Jin

2015-01-01

Because the family and consumer sciences body of knowledge (FCS-BOK) is the framework for the profession, students' familiarity with the FCS-BOK has implications for the profession. Using pre- (N = 78) and posttest (N = 43) data from students enrolled in an "Introduction to Family and Consumer Sciences" (FCS 160) undergraduate student…
Fluorescence correlation spectroscopy study of the complexation of DNA hybrids, IgG antibody, and a chimeric protein of IgG-binding ZZ domains fused with a carbohydrate binding module.

PubMed

Rosa, A M M; Prazeres, D M F; Paulo, P M R

2017-06-28

Fluorescence correlation spectroscopy (FCS) was used to characterize the molecular interactions between the four components of a DNA recognition system. A fluorescent DNA probe was used to assess: (i) the hybridization with a complementary biotin-labeled target, (ii) the complexation of the resulting hybrid and an anti-biotin antibody, and (iii) the binding of the latter complex to a ZZ-CBM fusion protein that combines small synthetic IgG Fc-binding Z domains with a carbohydrate binding module (CBM). These binding interactions were monitored by exposing the fluorescent DNA probe to different amounts and combinations of the other molecules in solution. Through the analysis of FCS autocorrelation curves, an association constant (K a ) of 2.9 × 10 7 M -1 was estimated for DNA·DNA hybridization, and the presence of (non-) complementary target DNA in solution could be discriminated. The specific capture of biotinylated DNA hybrids by anti-biotin IgG was verified, with an apparent K a of 2.5 × 10 6 M -1 . The increment in the diffusion time measured when the DNA·DNA:antibody complexes were in contact with the ZZ-CBM fusion protein suggested that the binding occurs at a stoichiometric ratio of DNA/antibody complex to fusion larger than 1 : 1. The FCS-derived information obtained is useful to gain insight into molecular interactions involved in diagnostic assays.
Characterizing the interactions between prolyl isomerase pin1 and phosphatase inhibitor-2 in living cells with FRET and FCS

NASA Astrophysics Data System (ADS)

Sun, Yuansheng; Wang, Lifu; Jyothikumar, Vinod; Brautigan, David L.; Periasamy, Ammasi

2012-03-01

Phosphatase inhibitor-2 (I2) was discovered as a regulator of protein Ser/Thr phosphatase-1 and is conserved from yeast to human. Binding between purified recombinant I2 from different species and the prolyl isomerase Pin1 has been demonstrated with pull-down assays, size exclusion chromatography and nuclear magnetic resonance spectroscopy. Despite this, questions persist as to whether these proteins associate together in living cells. In this study, we prepared fluorescent protein (FP) fusions of I2 and Pin1 and employed both Förster Resonance Energy Transfer (FRET) and Fluorescence Correlation Spectroscopy (FCS) imaging techniques to characterize their interactions in living cells. In both intensity-based and time-resolved FRET studies, we observed FRET uniformly across whole cells co-expressing I2-Cerulean and Pin1-Venus that was significantly higher than in negative controls expressing Cerulean FP (without fusing to I2) as the FRET donor and Pin1-Venus, showing a specific interaction between I2-Cerulean and Pin1-Venus in living cells. We also observed the co-diffusion of I2-Cerulean and Pin1-mCherry in Fluorescence Cross Correlation Spectroscopy (FCCS) measurements. We further showed that I2 itself as well as I2-Pin1 formed complexes in living cells (predicted from in vitro studies) via a quantitative FRET assay, and demonstrated from FCS measurements that both I2 and Pin1 (fused to Cerulean) are highly mobile in living cells.
A fluorescence correlation spectroscopy study of the diffusion of an organic dye in the gel phase and fluid phase of a single lipid vesicle.

PubMed

Ghosh, Subhadip; Adhikari, Aniruddha; Sen Mojumdar, Supratik; Bhattacharyya, Kankan

2010-05-06

The mobility of the organic dye DCM (4-dicyanomethylene-2-methyl-6-p-dimethyl aminostyryl-4H-pyran) in the gel and fluid phases of a lipid vesicle is studied by fluorescence correlation spectroscopy (FCS). Using FCS, translational diffusion of DCM is determined in the gel phase and fluid phase of a single lipid vesicle adhered to a glass surface. The size of a lipid vesicle (average diameter approximately 100 nm) is smaller than the diffraction limited spot size (approximately 250 nm) of the microscope. Thus, the vesicle is confined within the laser focus. Three lipid vesicles (1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)) having different gel transition temperatures (-1, 23, and 41 degrees C, respectively) were studied. The diffusion coefficient of the dye DCM in bulk water is approximately 300 microm(2)/s. In the lipid vesicle, the average D(t) decreases markedly to approximately 5 microm(2)/s (approximately 60 times) in the gel phase (for DPPC at 20 degrees C) and 40 microm(2)/s ( approximately 8 times) in the fluid phase (for DLPC at 20 degrees C). This clearly demonstrates higher mobility in the fluid phase compared with the gel phase of a lipid. It is observed that the D(t) values vary from lipid to lipid and there is a distribution of D(t) values. The diffusion of the hydrophobic dye DCM (D(t) approximately 5 microm(2)/s) in the DPPC vesicle is found to be 8 times smaller than that of a hydrophilic anioinic dye C343 (D(t) approximately 40 microm(2)/s). This is attributed to different locations of the hydrophobic (DCM) and hydrophilic (C343) dyes.
Influence of surface coating on the intracellular behaviour of gold nanoparticles: a fluorescence correlation spectroscopy study.

PubMed

Silvestri, A; Di Silvio, D; Llarena, I; Murray, R A; Marelli, M; Lay, L; Polito, L; Moya, S E

2017-10-05

In the biomedical applications of nanoparticles (NPs), the proper choice of surface chemistry is a crucial aspect in their design. The nature of the coating can heavily impact the interaction of NPs with biomolecules, affect the state of aggregation, and ultimately determine their biological fate. As such, protein corona formation and the aggregation behaviour of gold NPs (Au NPs) are studied here. Au NPs are prepared with four distinct surface functionalisations, namely mercaptosuccinic acid (MSA), N-4-thiobutyroil glucosamine, HS-PEG 5000 and HS-alkyl-PEG 600 . Corona formation, aggregation, and the intracellular behaviour of the Au NPs are then investigated by means of Fluorescence Correlation Spectroscopy (FCS) in cell culture media and in live cells. To evaluate the state of aggregation and the formation of a protein corona, the Au NPs are incubated in cell media and the diffusion coefficient is determined via FCS. The in vitro behaviour is compared with the level of aggregation of the NPs in cells. Diffusion times of the NPs are estimated at different positions in the cell after a one hour incubation period. It is found that the majority of MSA and glucose-Au NPs are present inside the cell as slowly diffusing species with diffusion times (τ D ) greater than 6000 μs (hydrodynamic diameter >250 nm). PEGylated Au NPs adsorb a small amount of protein and manifest low agglomeration both in media and in living cells. In particular, the HS-alkyl-PEG 600 coating shows an excellent correlation between lower protein adsorption, 4-fold lower compared to the MSA coated NPs, and limited intracellular aggregation. In the case of single HS-alkyl-PEG 600 coated NPs, it is found that typical intracellular τ D values range from 500 to 1500 μs, indicating that these particles display reduced aggregation in the intracellular environment.
A study of the dynamics of PTEN proteins in living cells using in vivo fluorescence correlation spectroscopy

NASA Astrophysics Data System (ADS)

Du, Zhixue; Dong, Chaoqing; Ren, Jicun

2017-06-01

PTEN (phosphatase and tensin homolog on chromosome 10) is one of the most important tumor-suppressor proteins, which plays a key role in negative regulation of the PI3K/AKT pathway, and governs many cellular processes including growth, proliferation, survival and migration. The dynamics of PTEN proteins in single living cells is as yet unclear owing to a shortage of suitable in vivo approaches. Here, we report a single-molecule method for in vivo study of the dynamics of PTEN proteins in living cells using fluorescence correlation spectroscopy (FCS). First, we established a monoclonal H1299 stable cell line expressing enhanced green fluorescent protein (EGFP) and PTEN (EGFP-PTEN) fusion proteins; we then developed an in vivo FCS method to study the dynamics of EGFP-PTEN both in the nucleus and the cytoplasm. We investigated the diffusion behaviors of EGFP and EGFP-PTEN in solution, nucleus and cytosol, and observed that the motion of PTEN in living cells was restricted compared with EGFP. Finally, we investigated the protein dynamics in living cells under oxidative stress stimulation and a cellular ATP depletion treatment. Under oxidative stress stimulation, the EGFP-PTEN concentration increased in the nucleus, but slightly decreased in the cytoplasm. The diffusion coefficient and alpha value of EGFP-PTEN reduced significantly both in the nucleus and cytoplasm; the significantly decreased alpha parameter indicates a more restricted Brownian diffusion behavior. Under the cellular ATP depletion treatment, the concentration of EGFP-PTEN remained unchanged in the nucleus and decreased significantly in cytosol. The diffusion coefficient of EGFP-PTEN decreased significantly in cytosol, but showed no significant change in the nucleus; the alpha value decreased significantly in both the nucleus and cytoplasm. These results suggest that the concentration and mobility of PTEN in the nucleus and cytoplasm can be regulated by stimulation methods. Our approach provides a unique method for real-time monitoring of protein dynamics in different subcellular compartments under different stimulation treatments.
Fucosylated chondroitin sulfate is covalently associated with collagen fibrils in sea cucumber Apostichopus japonicus body wall.

PubMed

Wang, Jun; Chang, Yaoguang; Wu, Fanxiu; Xu, Xiaoqi; Xue, Changhu

2018-04-15

Fucosylated chondroitin sulfate (fCS) is the major carbohydrate constituent of sea cucumber. However, the distribution of fCS in the sea cucumber body wall has not been fully described. We addressed this in the present study employing Apostichopus japonicus as the material, a sea cucumber species with significant commercial importance. It was found that fCS was covalently attached to collagen fibrils via O-glycosidic linkages. Transmission electron microscopy analysis revealed that fCS precipitate was present in gap regions of collagen fibrils as roughly globular or ellipsoidal dots. The fCS dots arranged circumferentially around the fibrils with an axial repeat period that matched the periodicity of the fibrils. Physicochemical analysis indicated that the presence of fCS significantly increased the negative charge of the fibrils. These findings provide novel insight into fCS distribution in the sea cucumber body wall and its supramolecular organization with other macromolecules. Copyright © 2018 Elsevier Ltd. All rights reserved.
Fucosylated chondroitin sulfates from the body wall of the sea cucumber Holothuria forskali: conformation, selectin binding, and biological activity.

PubMed

Panagos, Charalampos G; Thomson, Derek S; Moss, Claire; Hughes, Adam D; Kelly, Maeve S; Liu, Yan; Chai, Wengang; Venkatasamy, Radhakrishnan; Spina, Domenico; Page, Clive P; Hogwood, John; Woods, Robert J; Mulloy, Barbara; Bavington, Charlie D; Uhrín, Dušan

2014-10-10

Fucosylated chondroitin sulfate (fCS) extracted from the sea cucumber Holothuria forskali is composed of the following repeating trisaccharide unit: → 3)GalNAcβ4,6S(1 → 4) [FucαX(1 → 3)]GlcAβ(1 →, where X stands for different sulfation patterns of fucose (X = 3,4S (46%), 2,4S (39%), and 4S (15%)). As revealed by NMR and molecular dynamics simulations, the fCS repeating unit adopts a conformation similar to that of the Le(x) blood group determinant, bringing several sulfate groups into close proximity and creating large negative patches distributed along the helical skeleton of the CS backbone. This may explain the high affinity of fCS oligosaccharides for L- and P-selectins as determined by microarray binding of fCS oligosaccharides prepared by Cu(2+)-catalyzed Fenton-type and photochemical depolymerization. No binding to E-selectin was observed. fCS poly- and oligosaccharides display low cytotoxicity in vitro, inhibit human neutrophil elastase activity, and inhibit the migration of neutrophils through an endothelial cell layer in vitro. Although the polysaccharide showed some anti-coagulant activity, small oligosaccharide fCS fragments had much reduced anticoagulant properties, with activity mainly via heparin cofactor II. The fCS polysaccharides showed prekallikrein activation comparable with dextran sulfate, whereas the fCS oligosaccharides caused almost no effect. The H. forskali fCS oligosaccharides were also tested in a mouse peritoneal inflammation model, where they caused a reduction in neutrophil infiltration. Overall, the data presented support the action of fCS as an inhibitor of selectin interactions, which play vital roles in inflammation and metastasis progression. Future studies of fCS-selectin interaction using fCS fragments or their mimetics may open new avenues for therapeutic intervention. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.
"Oh, yeah, I'm getting closer to god": spirituality and religiousness of family caregivers of cancer patients undergoing palliative care.

PubMed

Paiva, Bianca Sakamoto Ribeiro; Carvalho, André Lopes; Lucchetti, Giancarlo; Barroso, Eliane Marçon; Paiva, Carlos Eduardo

2015-08-01

Within the cancer palliative care setting, where both patients and family caregivers (FCs) undergo a transition from the end of curative treatment to palliative therapy, spirituality and religiousness (S/R) may be a strategy to help the patients and FCs better cope with the disease, in addition to exerting a positive impact on symptoms, particularly emotional symptoms. The present study aimed to understand how S/R influence FCs of cancer patients undergoing palliative care. This study was an exploratory and descriptive qualitative study. The qualitative approach to the data was based on Bardin's content analysis technique. The consolidated criteria for reporting qualitative research (COREQ-32) was used in the description of the results. Thirty FCs of individuals with advanced cancer undergoing palliative care were included. Analysis of the FCs' narratives indicated that the FCs considered that religiousness and faith in God or a Supreme Being provide them with the strength to cope with the suffering associated with the care of relatives with advanced cancer. Many FCs emphasized that talking about God was somehow comforting and made them feel at peace with themselves. Four categories were identified in the FCs' narratives: (1) increase in faith and closeness to God becomes stronger, (2) rethink life issues, (3) negative interference in the extrinsic religiosity, and (4) quest for religiousness to gain strength or support. A conceptual framework was developed. The results of the present study indicated that S/R are a coping strategy frequently used by FCs of individuals with advanced cancer. The perceptions of the FCs interviewed in the present study corresponded to the four distinct categories related to spirituality and religiousness.
Practitioner perspectives on foundational capabilities.

PubMed

Leider, Jonathon P; Juliano, Chrissie; Castrucci, Brian C; Beitsch, Leslie M; Dilley, Abby; Nelson, Rachel; Kaiman, Sherry; Sprague, James B

2015-01-01

National efforts are underway to classify a minimum set of public health services that all jurisdictions throughout the United States should provide regardless of location. Such a set of basic programs would be supported by crosscutting services, known as the "foundational capabilities" (FCs). These FCs are assessment services, preparedness and disaster response, policy development, communications, community partnership, and organizational support activities. To ascertain familiarity with the term and concept of FCs and gather related perspectives from state and local public health practitioners. In fall 2013, we interviewed 50 leaders from state and local health departments. We asked about familiarity with the term "foundational capabilities," as well as the broader concept of FCs. We attempted to triangulate the utility of the FC concept by asking respondents about priority programs and services, about perceived unique contributions made by public health, and about prevalence and funding for the FCs. Telephone-based interviews. Fifty leaders of state and local health departments. Practitioner familiarity with and perspectives on the FCs, information about current funding streams for public health, and the likelihood of creating nationwide FCs that would be recognized and accepted by all jurisdictions. Slightly more than half of the leaders interviewed said that they were familiar with the concept of FCs. In most cases, health departments had all of the capabilities to some degree, although operationalization varied. Few indicated that current funding levels were sufficient to support implementing a minimum level of FCs nationally. Respondents were not able to articulate the current or optimal levels of services for the various capabilities, nor the costs associated with them. Further research is needed to understand the role of FCs as part of the foundational public health services.
Spontaneous autoimmune gastritis and hypochlorhydria are manifest in the ileitis-prone SAMP1/YitFcs mice.

PubMed

Ernst, P B; Erickson, L D; Loo, W M; Scott, K G; Wiznerowicz, E B; Brown, C C; Torres-Velez, F J; Alam, M S; Black, S G; McDuffie, M; Feldman, S H; Wallace, J L; McKnight, G W; Padol, I T; Hunt, R H; Tung, K S

2012-01-01

SAMP1/YitFcs mice serve as a model of Crohn's disease, and we have used them to assess gastritis. Gastritis was compared in SAMP1/YitFcs, AKR, and C57BL/6 mice by histology, immunohistochemistry, and flow cytometry. Gastric acid secretion was measured in ligated stomachs, while anti-parietal cell antibodies were assayed by immunofluorescence and enzyme-linked immunosorbent spot assay. SAMP1/YitFcs mice display a corpus-dominant, chronic gastritis with multifocal aggregates of mononuclear cells consisting of T and B lymphocytes. Relatively few aggregates were observed elsewhere in the stomach. The infiltrates in the oxyntic mucosa were associated with the loss of parietal cell mass. AKR mice, the founder strain of the SAMP1/YitFcs, also have gastritis, although they do not develop ileitis. Genetic studies using SAMP1/YitFcs-C57BL/6 congenic mice showed that the genetic regions regulating ileitis had comparable effects on gastritis. The majority of the cells in the aggregates expressed the T cell marker CD3 or the B cell marker B220. Adoptive transfer of SAMP1/YitFcs CD4(+) T helper cells, with or without B cells, into immunodeficient recipients induced a pangastritis and duodenitis. SAMP1/YitFcs and AKR mice manifest hypochlorhydria and anti-parietal cell antibodies. These data suggest that common genetic factors controlling gastroenteric disease in SAMP1/YitFcs mice regulate distinct pathogenic mechanisms causing inflammation in separate sites within the digestive tract.
Data File Standard for Flow Cytometry, version FCS 3.1.

PubMed

Spidlen, Josef; Moore, Wayne; Parks, David; Goldberg, Michael; Bray, Chris; Bierre, Pierre; Gorombey, Peter; Hyun, Bill; Hubbard, Mark; Lange, Simon; Lefebvre, Ray; Leif, Robert; Novo, David; Ostruszka, Leo; Treister, Adam; Wood, James; Murphy, Robert F; Roederer, Mario; Sudar, Damir; Zigon, Robert; Brinkman, Ryan R

2010-01-01

The flow cytometry data file standard provides the specifications needed to completely describe flow cytometry data sets within the confines of the file containing the experimental data. In 1984, the first Flow Cytometry Standard format for data files was adopted as FCS 1.0. This standard was modified in 1990 as FCS 2.0 and again in 1997 as FCS 3.0. We report here on the next generation flow cytometry standard data file format. FCS 3.1 is a minor revision based on suggested improvements from the community. The unchanged goal of the standard is to provide a uniform file format that allows files created by one type of acquisition hardware and software to be analyzed by any other type.The FCS 3.1 standard retains the basic FCS file structure and most features of previous versions of the standard. Changes included in FCS 3.1 address potential ambiguities in the previous versions and provide a more robust standard. The major changes include simplified support for international characters and improved support for storing compensation. The major additions are support for preferred display scale, a standardized way of capturing the sample volume, information about originality of the data file, and support for plate and well identification in high throughput, plate based experiments. Please see the normative version of the FCS 3.1 specification in Supporting Information for this manuscript (or at http://www.isac-net.org/ in the Current standards section) for a complete list of changes.
Data File Standard for Flow Cytometry, Version FCS 3.1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spidlen, Josef; Moore, Wayne; Parks, David

2009-11-10

The flow cytometry data file standard provides the specifications needed to completely describe flow cytometry data sets within the confines of the file containing the experimental data. In 1984, the first Flow Cytometry Standard format for data files was adopted as FCS 1.0. This standard was modified in 1990 as FCS 2.0 and again in 1997 as FCS 3.0. We report here on the next generation flow cytometry standard data file format. FCS 3.1 is a minor revision based on suggested improvements from the community. The unchanged goal of the standard is to provide a uniform file format that allowsmore » files created by one type of acquisition hardware and software to be analyzed by any other type. The FCS 3.1 standard retains the basic FCS file structure and most features of previous versions of the standard. Changes included in FCS 3.1 address potential ambiguities in the previous versions and provide a more robust standard. The major changes include simplified support for international characters and improved support for storing compensation. The major additions are support for preferred display scale, a standardized way of capturing the sample volume, information about originality of the data file, and support for plate and well identification in high throughput, plate based experiments. Please see the normative version of the FCS 3.1 specification in Supporting Information for this manuscript (or at http://www.isac-net.org/ in the Current standards section) for a complete list of changes.« less
Fluorescence correlation spectroscopy: principles and applications.

PubMed

Bacia, Kirsten; Haustein, Elke; Schwille, Petra

2014-07-01

Fluorescence correlation spectroscopy (FCS) is used to study the movements and the interactions of biomolecules at extremely dilute concentrations, yielding results with good spatial and temporal resolutions. Using a number of technical developments, FCS has become a versatile technique that can be used to study a variety of sample types and can be advantageously combined with other methods. Unlike other fluorescence-based techniques, the analysis of FCS data is not based on the average intensity of the fluorescence emission but examines the minute intensity fluctuations caused by spontaneous deviations from the mean at thermal equilibrium. These fluctuations can result from variations in local concentrations owing to molecular mobility or from characteristic intermolecular or intramolecular reactions of fluorescently labeled biomolecules present at low concentrations. Here, we provide a basic introduction to FCS, including its technical development and theoretical basis, experimental setup of an FCS system, adjustment of a setup, data acquisition, and analysis of FCS measurements. Finally, the application of FCS to the study of lipid bilayer membranes and to living cells is discussed. © 2014 Cold Spring Harbor Laboratory Press.

2007 Combat Vehicles Conference - Today’s Challenges: Fighting, Sustaining, Modernizing and Transforming

DTIC Science & Technology

2007-10-24

Programs) 1 . FCS MULE .wmv format 2. FCS NLOS Crate Of Fire .wmv format 3. FCS Robotic Convoy .wmv format 4. FCS...included in these sessions will be two “back by popular demand” highlights from previous conferences: 1 ) an update on combat operations in iraq from...15 am - 11:30 am general session general sessiOn - sessiOn 1 : “today’s challenges: fighting, sustaining, modernizing and transforming
Freezing solution containing dimethylsulfoxide and fetal calf serum maintains survival and ultrastructure of goat preantral follicles after cryopreservation and in vitro culture of ovarian tissue.

PubMed

Castro, Simone Vieira; de Carvalho, Adeline Andrade; da Silva, Cleidson Manoel Gomes; Faustino, Luciana Rocha; Campello, Cláudio Cabral; Lucci, Carolina Madeira; Báo, Sônia Nair; de Figueiredo, José Ricardo; Rodrigues, Ana Paula Ribeiro

2011-11-01

Goat ovarian cortex fragments were subjected to slow freezing in the presence of various solutions containing intracellular cryoprotectants, including 1.0 M ethylene glycol (EG), propanediol (PROH), or dimethyl sulfoxide (DMSO), with or without sucrose and/or fetal calf serum (FCS). Histological examination revealed that only the DMSO-containing solutions were able to maintain a follicular ultrastructure similar to the morphology observed in the fresh control. Therefore, fragments previously cryopreserved in DMSO solutions (with and without sucrose and/or FCS) were cultured in vitro for 48 h and then subjected to viability, histological, and ultrastructural analysis. No significant differences were observed among the percentages of morphologically normal follicles in cryopreserved ovarian tissue before in vitro culture (DMSO: 62.5%; DMSO + sucrose: 68.3%; DMSO + FCS: 60.0%; DMSO + sucrose + FCS: 60.0%) and after culture (DMSO: 60.8%; DMSO + sucrose: 64.2%; DMSO + FCS: 70.8%; DMSO + sucrose + FCS: 55.0%). Following in vitro culture, the viability analysis showed that only the freezing solution containing DMSO and FCS (75.6%) maintained a percentage of viable follicles similar to that observed after culture without cryopreservation (89.3%). As determined by ultrastructural analysis, morphologically normal preantral follicles were detected in the fresh control and in fragments cultured before and after cryopreservation with DMSO and FCS. Thus, a freezing solution containing DMSO and FCS, under the experimental conditions tested here, guaranteed the maintenance of viability and follicular ultrastructure after short-term in vitro culture.
Spontaneous autoimmune gastritis and hypochlorhydria are manifest in the ileitis-prone SAMP1/YitFcs mice

PubMed Central

Erickson, L. D.; Loo, W. M.; Scott, K. G.; Wiznerowicz, E. B.; Brown, C. C.; Torres-Velez, F. J.; Alam, M. S.; Black, S. G.; McDuffie, M.; Feldman, S. H.; Wallace, J. L.; McKnight, G. W.; Padol, I. T.; Hunt, R. H.; Tung, K. S.

2012-01-01

SAMP1/YitFcs mice serve as a model of Crohn's disease, and we have used them to assess gastritis. Gastritis was compared in SAMP1/YitFcs, AKR, and C57BL/6 mice by histology, immunohistochemistry, and flow cytometry. Gastric acid secretion was measured in ligated stomachs, while anti-parietal cell antibodies were assayed by immunofluorescence and enzyme-linked immunosorbent spot assay. SAMP1/YitFcs mice display a corpus-dominant, chronic gastritis with multifocal aggregates of mononuclear cells consisting of T and B lymphocytes. Relatively few aggregates were observed elsewhere in the stomach. The infiltrates in the oxyntic mucosa were associated with the loss of parietal cell mass. AKR mice, the founder strain of the SAMP1/YitFcs, also have gastritis, although they do not develop ileitis. Genetic studies using SAMP1/YitFcs-C57BL/6 congenic mice showed that the genetic regions regulating ileitis had comparable effects on gastritis. The majority of the cells in the aggregates expressed the T cell marker CD3 or the B cell marker B220. Adoptive transfer of SAMP1/YitFcs CD4+ T helper cells, with or without B cells, into immunodeficient recipients induced a pangastritis and duodenitis. SAMP1/YitFcs and AKR mice manifest hypochlorhydria and anti-parietal cell antibodies. These data suggest that common genetic factors controlling gastroenteric disease in SAMP1/YitFcs mice regulate distinct pathogenic mechanisms causing inflammation in separate sites within the digestive tract. PMID:21921286
Multiple Glass Transitions and Freezing Events of Aqueous Citric Acid

PubMed Central

2014-01-01

Calorimetric and optical cryo-microscope measurements of 10–64 wt % citric acid (CA) solutions subjected to moderate (3 K/min) and slow (0.5 and 0.1 K/min) cooling/warming rates and also to quenching/moderate warming between 320 and 133 K are presented. Depending on solution concentration and cooling rate, the obtained thermograms show one freezing event and from one to three liquid–glass transitions upon cooling and from one to six liquid–glass and reverse glass–liquid transitions, one or two freezing events, and one melting event upon warming of frozen/glassy CA/H2O. The multiple freezing events and glass transitions pertain to the mother CA/H2O solution itself and two freeze-concentrated solution regions, FCS1 and FCS2, of different concentrations. The FCS1 and FCS2 (or FCS22) are formed during the freezing of CA/H2O upon cooling and/or during the freezing upon warming of partly glassy or entirely glassy mother CA/H2O. The formation of two FCS1 and FCS22 regions during the freezing upon warming to our best knowledge has never been reported before. Using an optical cryo-microscope, we are able to observe the formation of a continuous ice framework (IF) and its morphology and reciprocal distribution of IF/(FCS1 + FCS2). Our results provide a new look at the freezing and glass transition behavior of aqueous solutions and can be used for the optimization of lyophilization and freezing of foods and biopharmaceutical formulations, among many other applications where freezing plays a crucial role. PMID:25482069
Communication During Pediatric Intensive Care Unit Family Conferences: A Pilot Study of Content, Communication, and Parent Perceptions.

PubMed

Michelson, Kelly; Clayman, Marla L; Ryan, Claire; Emanuel, Linda; Frader, Joel

2017-10-01

While there is a robust literature describing family conferences (FCs) in adult intensive care units (ICUs), less information exists about FCs in pediatric ICUs (PICUs). We conducted a pilot study to describe the focus of discussion, communication patterns of health care team members (HTMs) and parents, and parents' perspectives about clinician communication during PICU FCs. We analyzed data from 22 video- or audiorecorded PICU FCs and post-FC questionnaire responses from 27 parents involved in 18 FCs. We used the Roter Interaction Analysis System (RIAS) to describe FC dialogue content. Our questionnaire included the validated Communication Assessment Tool (CAT). FCs were focused on care planning (n = 5), decision making (n = 6), and updates (n = 11). Most speech came from HTMs (mean 85%; range, 65-94%). Most HTM utterances involved medical information. Most parent utterances involved asking for explanations. The mean overall CAT score was 4.62 (using a 1-5 scale where 5 represents excellent and 1 poor) with a mean of 73.02% "excellent" responses. Update and care-planning FCs had lower CAT scores compared to decision-making FCs. The lowest scoring CAT items were "Involved me in decisions as much as I wanted," "Talked in terms I could understand," and "Gave me as much information as I wanted." These findings suggest that while health care providers spend most of their time during FCs relaying medical information, more attention should be directed at providing information in an understandable manner. More work is needed to improve communication when decision making is not the main focus of the FC.
FCS Students' Attitudes and Intentions toward Entrepreneurial Careers

ERIC Educational Resources Information Center

Frazier, Barbara; Niehm, Linda S.

2008-01-01

Growing interest in entrepreneurship among younger workers has implications for university family and consumer sciences (FCS) programs. This study assessed FCS majors' attitudes toward entrepreneurship as a career path. Students viewed entrepreneurship opportunities as attractive and were confident about their possibilities for success; however,…
Developing UGVs for the FCS program

NASA Astrophysics Data System (ADS)

Kamsickas, Gary M.; Ward, John N.

2003-09-01

The FCS Operational Requirements Document (ORD) identifies unmanned systems as a key component of the FCS Unit of Action. FCS unmanned systems include Unmanned Aerial Vehicles (UAV), Unmanned Ground Vehicles (UGV), Unattended Ground Sensors (UGS) and Unattended Munitions (UM). Unmanned systems are intended to enhance the Unit of Action across the full range of operations when integrated with manned platforms. Unmanned systems will provide the commander with tools to gather battlespace information while significantly reducing overall soldier risk. Unmanned systems will be used in some cases to augment or replace human intervention to perform many of the dirty, dull and dangerous missions presently performed by soldiers and to serve as a combat multiplier for mission performance, force protection and survivability. This paper focuses on the application of UGVs within the FCS Unit of Action. There are three different UGVs planned to support the FCS Unit of Action; the Soldier Unmanned Ground Vehicle (SUGV); The Multi-role Utility Logistics Equipment (MULE) platform; and the Armed Robotic Vehicle (ARV).
Using short-range and long-range functional connectivity to identify schizophrenia with a family-based case-control design.

PubMed

Guo, Wenbin; Liu, Feng; Chen, Jindong; Wu, Renrong; Li, Lehua; Zhang, Zhikun; Chen, Huafu; Zhao, Jingping

2017-06-30

Abnormal short-range and long-range functional connectivities (FCs) have been implicated in the neurophysiology of schizophrenia. This study was conducted to examine the potential of short-range and long-range FCs for differentiating the patients from the controls with a family-based case-control design. Twenty-eight first-episode, drug-naive patients with schizophrenia, 28 unaffected siblings of the patients (family-based controls, FBCs), and 40 healthy controls (HCs) underwent resting-state functional magnetic resonance imaging (fMRI) scans. The data were analyzed by short-range and long-range FC analyses, receiver operating characteristic curve (ROC) and support vector machine (SVM). Compared with the FBCs/HCs, the patients exhibit increased short-range positive FC strength (spFCS) and/or long-range positive FC strength (lpFCS) in the default-mode network (DMN) and decreased spFCS and lpFCS in the sensorimotor circuits. Furthermore, a combination of the spFCS values in the right superior parietal lobule and the lpFCS values in the left fusiform gyrus/cerebellum VI can differentiate the patients from the FBCs with high sensitivity and specificity. The findings highlight the importance of the DMN and sensorimotor circuits in the pathogenesis of schizophrenia. Combining with family-based case-control design may be a viable option to limit the confounding effects of environmental risk factors in neuroimaging studies of schizophrenia. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.
Bring Engineering to Life: Pergola Design

ERIC Educational Resources Information Center

Dorrell, Abby; Berkeihiser, Mike

2014-01-01

The Family and Consumer Science (FCS) Department at Charles F. Patton Middle School in Kennett Square, Pennsylvania, planted a garden to provide students with an organic horticulture experience. Although the garden provided the FCS Department space to grow plants, Patton Middle School FCS teachers Betsy Ballard and Kim Hislert believed it wasn't…
Using Newspapers in the FCS Curriculum

ERIC Educational Resources Information Center

Brandes, Kendra

2008-01-01

This article examines a number of issues facing family and consumer sciences (FCS) teachers in today's middle and high school classrooms and reviews literature supporting the use of newspapers as a valuable teaching resource in light of these issues. Suggestions for using newspapers and newspaper industry resources to enhance the FCS curriculum…
Filling the Educator Pipeline: Recruiting Male Family and Consumer Sciences Teachers

ERIC Educational Resources Information Center

Godfrey, Roxie V.; Manis, Kerry T.

2017-01-01

To encourage males to enter the teaching field, specifically in family and consumer sciences (FCS), FCS professionals should participate in recruitment initiatives aimed at males. Administrators, teacher educators, career counselors, and FCS teachers can play a significant role in this comprehensive and systematic effort. This paper adopts the…
Teaching Strategies for Diverse Learners in FCS Classrooms

ERIC Educational Resources Information Center

Allison, Barbara N.; Rehm, Marsha L.

2007-01-01

The growing diversity in today's classrooms demands that family and consumer sciences (FCS) teachers be knowledgeable, responsive, and well-prepared to work with a multicultural, multilingual student population. To meet the needs of students from all backgrounds, FCS teachers must use a broad array of research-based strategies that support diverse…
AAFCS Webinars: Statewide Opportunities for FCS Educators

ERIC Educational Resources Information Center

Kohl, Mary Jo

2012-01-01

Due to budget restrictions over recent years, the state of Ohio has limited the number of face-to-face state consultant implemented professional development seminars for educators to attend. In order to meet the professional development demands of Ohio family and consumer sciences (FCS) teachers, the Ohio Department of Education FCS consultant…
Dual-color two-photon fluorescence correlation spectroscopy

NASA Astrophysics Data System (ADS)

Berland, Keith M.

2001-04-01

Fluorescence correlation spectroscopy (FCS) is rapidly growing in popularity as a research tool in biological and biophysical research. Under favorable conditions, FCS measurements can produce an accurate characterization of the chemical, physical, and kinetic properties of a biological system. However, interpretation of FCS data quickly becomes complicated as the heterogeneity of a molecular system increases, as well as when there is significant non-stationery fluorescence background (e.g. intracellular autofluorescence). Use of multi-parameter correlation measurements is one promising approach that can improve the fidelity of FCS measurements in complex systems. In particular, the use of dual-color fluorescence assays, in which different interacting molecular species are labeled with unique fluorescent indicators, can "tune" the sensitivity of FCS measurements in favor of particular molecular species of interest, while simultaneously minimizing the contribution of other molecular species to the overall fluorescence correlation signal. Here we introduce the combined application of two-photon fluorescence excitation and dual-color cross-correlation analysis for detecting molecular interactions in solution. The use of two-photon excitation is particularly advantageous for dual-color FCS applications due to the uncomplicated optical alignment and the superior capabilities for intracellular applications. The theory of two-photon dual-color FCS is introduced, and initial results quantifying hybridization reactions between three independent single stranded DNA molecules are presented.
Studying ion exchange in solution and at biological membranes by FCS.

PubMed

Widengren, Jerker

2013-01-01

By FCS, a wide range of processes can be studied, covering time ranges from subnanoseconds to seconds. In principle, any process at equilibrium conditions can be measured, which reflects itself by a change in the detected fluorescence intensity. In this review, it is described how FCS and variants thereof can be used to monitor ion exchange, in solution and along biological membranes. Analyzing fluorescence fluctuations of ion-sensitive fluorophores by FCS offers selective advantages over other techniques for measuring local ion concentrations, and, in particular, for studying exchange kinetics of ions on a very local scale. This opens for several areas of application. The FCS approach was used to investigate fundamental aspects of proton exchange at and along biological membranes. The protonation relaxation rate, as measured by FCS for a pH-sensitive dye, can also provide information about local accessibility/interaction of a particular labeling site and conformational states of biomolecules, in a similar fashion as in a fluorescence quenching experiment. The same FCS concept can also be applied to ion exchange studies using other ion-sensitive fluorophores, and by use of dyes sensitive to other ambient conditions the concept can be extended also beyond ion exchange studies. Copyright © 2013 Elsevier Inc. All rights reserved.
A Chemically Defined Medium for Rabbit Embryo Cryopreservation

PubMed Central

Bruyère, Pierre; Baudot, Anne; Joly, Thierry; Commin, Loris; Pillet, Elodie; Guérin, Pierre; Louis, Gérard; Josson-Schramme, Anne; Buff, Samuel

2013-01-01

This study evaluates a new synthetic substitute (CRYO3, Ref. 5617, Stem Alpha, France) for animal-based products in rabbit embryo cryopreservation solutions. This evaluation was performed using two approaches: a thermodynamic approach using differential scanning calorimetry and a biological approach using rabbit embryo slow-freezing. During the experiment, foetal calf serum (FCS) was used as a reference. Because FCS varies widely by supplier, three different FCS were selected for the thermodynamic approach. The rabbit embryo slow-freezing solutions were made from Dulbecco's phosphate buffer saline containing 1.5 M Dimethyl Sulfoxide and 18% (v.v−1) of CRYO3 or 18% (v.v−1) of FCS. These solutions were evaluated using four characteristics: the end of melting temperature, the enthalpy of crystallisation (thermodynamic approach) and the embryo survival rates after culture and embryo transfer (biological approach). In the thermodynamic approach, the solutions containing one of the three different FCS had similar mean thermodynamic characteristics but had different variabilities in the overall data with aberrant values. The solution containing CRYO3 had similar thermodynamic properties when compared to those containing FCS. Moreover, no aberrant value was measured in the solution containing CRYO3. This solution appears to be more stable than the solutions containing a FCS. In the biological approach, the in vitro embryo survival rates obtained with the solution containing CRYO3 (73.7% and 81.3%) and with the solution containing a FCS (77.6% and 71.9%) were similar (p = 0.7). Nevertheless, during the in vivo evaluation, the implantation rate (21.8%) and the live-foetuses rate (18.8%) of the CRYO3 group were significantly higher than the implantation rate (7.1%, p = 0.0002) and the live-foetuses rate (5.3%, p = 0.0002) of the FCS group. The pregnancy rate was also higher in the CRYO3 group compared to the FCS group (81.3% and 43.8%, respectively, p = 0.066). We conclude that CRYO3 can be used as a chemically defined substitute for animal-based products in rabbit embryo cryopreservation solutions. PMID:23977074
A comparison of multiple imputation methods for handling missing values in longitudinal data in the presence of a time-varying covariate with a non-linear association with time: a simulation study.

PubMed

De Silva, Anurika Priyanjali; Moreno-Betancur, Margarita; De Livera, Alysha Madhu; Lee, Katherine Jane; Simpson, Julie Anne

2017-07-25

Missing data is a common problem in epidemiological studies, and is particularly prominent in longitudinal data, which involve multiple waves of data collection. Traditional multiple imputation (MI) methods (fully conditional specification (FCS) and multivariate normal imputation (MVNI)) treat repeated measurements of the same time-dependent variable as just another 'distinct' variable for imputation and therefore do not make the most of the longitudinal structure of the data. Only a few studies have explored extensions to the standard approaches to account for the temporal structure of longitudinal data. One suggestion is the two-fold fully conditional specification (two-fold FCS) algorithm, which restricts the imputation of a time-dependent variable to time blocks where the imputation model includes measurements taken at the specified and adjacent times. To date, no study has investigated the performance of two-fold FCS and standard MI methods for handling missing data in a time-varying covariate with a non-linear trajectory over time - a commonly encountered scenario in epidemiological studies. We simulated 1000 datasets of 5000 individuals based on the Longitudinal Study of Australian Children (LSAC). Three missing data mechanisms: missing completely at random (MCAR), and a weak and a strong missing at random (MAR) scenarios were used to impose missingness on body mass index (BMI) for age z-scores; a continuous time-varying exposure variable with a non-linear trajectory over time. We evaluated the performance of FCS, MVNI, and two-fold FCS for handling up to 50% of missing data when assessing the association between childhood obesity and sleep problems. The standard two-fold FCS produced slightly more biased and less precise estimates than FCS and MVNI. We observed slight improvements in bias and precision when using a time window width of two for the two-fold FCS algorithm compared to the standard width of one. We recommend the use of FCS or MVNI in a similar longitudinal setting, and when encountering convergence issues due to a large number of time points or variables with missing values, the two-fold FCS with exploration of a suitable time window.
Plumage condition in laying hens: genetic parameters for direct and indirect effects in two purebred layer lines.

PubMed

Brinker, Tessa; Bijma, Piter; Visscher, Jeroen; Rodenburg, T Bas; Ellen, Esther D

2014-05-29

Feather pecking is a major welfare issue in laying hen industry that leads to mortality. Due to a ban on conventional cages in the EU and on beak trimming in some countries of the EU, feather pecking will become an even bigger problem. Its severity depends both on the victim receiving pecking and on its group mates inflicting pecking (indirect effects), which together determine plumage condition of the victim. Plumage condition may depend, therefore, on both the direct genetic effect of an individual itself and on the indirect genetic effects of its group mates. Here, we present estimated genetic parameters for direct and indirect effects on plumage condition of different body regions in two purebred layer lines, and estimates of genetic correlations between body regions. Feather condition scores (FCS) were recorded at 40 weeks of age for neck, back, rump and belly and these four scores were added-up into a total FCS. A classical animal model and a direct-indirect effects model were used to estimate genetic parameters for FCS. In addition, a bivariate model with mortality (0/1) was used to account for mortality before recording FCS. Due to mortality during the first 23 weeks of laying, 5363 (for W1) and 5089 (for WB) FCS records were available. Total heritable variance for FCS ranged from 1.5% to 9.8% and from 9.8% to 53.6% when estimated respectively with the classical animal and the direct-indirect effects model. The direct-indirect effects model had a significantly higher likelihood. In both lines, 70% to 94% of the estimated total heritable variation in FCS was due to indirect effects. Using bivariate analysis of FCS and mortality did not affect estimates of genetic parameters. Genetic correlations were high between adjacent regions for FCS on neck, back, and rump but moderate to low for belly with other regions. Our results show that 70% to 94% of the heritable variation in FCS relates to indirect effects, indicating that methods of genetic selection that include indirect genetic effects offer perspectives to improve plumage condition in laying hens. This, in turn could reduce a major welfare problem.
Preparing FCS Professionals for a Multilingual Society: Building Community through the Experiences of Multilingual Families

ERIC Educational Resources Information Center

Duncan, Janine; Duncan, Daniel

2014-01-01

As demographics in the United States shift, family and consumer sciences (FCS) professionals must be prepared to foster healthy communities that embrace multilingual families. Because hegemonic language ideologies challenge multilingual families, FCS professionals need to know how to inclusively reframe communities to honor multilingual families.…
Interior Design Standards in the Secondary FCS Curriculum

ERIC Educational Resources Information Center

Katz, Shana H.; Smith, Bettye P.

2006-01-01

This article deals with a study on interior design standards in the secondary FCS curriculum. This study assessed the importance FCS teachers placed on content standards in the interior design curriculum to help determine the amount of time and emphasis to place on the units within the courses. A cover letter and questionnaire were sent…

Process versus Product: What Ethic Does the FCS-BOK Uphold?

ERIC Educational Resources Information Center

Roubanis, Jody L.

2017-01-01

Fundamental moral implications for professional practice inherent to the Family and Consumer Sciences Body of Knowledge (FCS-BOK) are revealed by using paradigms conventional to normative ethics. A product-oriented teleological ethic is linked to the FCS-BOK core concepts: basic human needs, individual well-being, family strengths, and community…
Grief and the Internet: Insights for FCS Professionals

ERIC Educational Resources Information Center

Gianatassio, Heather M.; Kimberly, Claire

2014-01-01

Working with individuals dealing with death and loss can be particularly challenging for family and consumer sciences (FCS) professionals, but what is unknown is how FCS practitioners can utilize social media to understand and assist in the mourning process. The purpose of this study was to gather information about grieving via online social…
Group Work and Leadership: Perception of FCS Students

ERIC Educational Resources Information Center

Arendt, Susan W.; Gregoire, Mary B.

2006-01-01

No known studies have examined the perception of family and consumer science (FCS) students related to group work in the classroom and its relationship to leadership. In this qualitative study, two groups of FCS students--hospitality management and dietetics--viewed group projects as exercises in leadership skills that had many barriers.…
Enumerating virus-like particles in an optically concentrated suspension by fluorescence correlation spectroscopy.

PubMed

Hu, Yi; Cheng, Xuanhong; Daniel Ou-Yang, H

2013-01-01

Fluorescence correlation spectroscopy (FCS) is one of the most sensitive methods for enumerating low concentration nanoparticles in a suspension. However, biological nanoparticles such as viruses often exist at a concentration much lower than the FCS detection limit. While optically generated trapping potentials are shown to effectively enhance the concentration of nanoparticles, feasibility of FCS for enumerating field-enriched nanoparticles requires understanding of the nanoparticle behavior in the external field. This paper reports an experimental study that combines optical trapping and FCS to examine existing theoretical predictions of particle concentration. Colloidal suspensions of polystyrene (PS) nanospheres and HIV-1 virus-like particles are used as model systems. Optical trapping energies and statistical analysis are used to discuss the applicability of FCS for enumerating nanoparticles in a potential well produced by a force field.
Short-term preservation of porcine oocytes in ambient temperature: novel approaches.

PubMed

Yang, Cai-Rong; Miao, De-Qiang; Zhang, Qing-Hua; Guo, Lei; Tong, Jing-Shan; Wei, Yanchang; Huang, Xin; Hou, Yi; Schatten, Heide; Liu, ZhongHua; Sun, Qing-Yuan

2010-12-07

The objective of this study was to evaluate the feasibility of preserving porcine oocytes without freezing. To optimize preservation conditions, porcine cumulus-oocyte complexes (COCs) were preserved in TCM-199, porcine follicular fluid (pFF) and FCS at different temperatures (4°C, 20°C, 25°C, 27.5°C, 30°C and 38.5°C) for 1 day, 2 days or 3 days. After preservation, oocyte morphology, germinal vesicle (GV) rate, actin cytoskeleton organization, cortical granule distribution, mitochondrial translocation and intracellular glutathione level were evaluated. Oocyte maturation was indicated by first polar body emission and spindle morphology after in vitro culture. Strikingly, when COCs were stored at 27.5°C for 3 days in pFF or FCS, more than 60% oocytes were still arrested at the GV stage and more than 50% oocytes matured into MII stages after culture. Almost 80% oocytes showed normal actin organization and cortical granule relocation to the cortex, and approximately 50% oocytes showed diffused mitochondria distribution patterns and normal spindle configurations. While stored in TCM-199, all these criteria decreased significantly. Glutathione (GSH) level in the pFF or FCS group was higher than in the TCM-199 group, but lower than in the non-preserved control group. The preserved oocytes could be fertilized and developed to blastocysts (about 10%) with normal cell number, which is clear evidence for their retaining the developmental potentiality after 3d preservation. Thus, we have developed a simple method for preserving immature pig oocytes at an ambient temperature for several days without evident damage of cytoplasm and keeping oocyte developmental competence.
Trends that FCS Education Should Address: A Delphi Study Reveals Top 16

ERIC Educational Resources Information Center

Alexander, Karen L.; Davis, Kimberlee

2011-01-01

This study used the Delphi method to identify trends of importance to family and consumer sciences (FCS) education. A panel of 21 FCS education experts identified 16 trends and evaluated them by importance, desirability, feasibility, and confidence in validity of the trend. Nutrition appeared as a top priority, followed by consumer economics. The…
Assessing Historically Black College and University (HBCU) Students' Familiarity with the FCS-BOK

ERIC Educational Resources Information Center

Lee, Sung-Jin; Williams-Wheeler, Meeshay; Walker, Jane

2015-01-01

University faculty who are teaching courses in family and consumer sciences (FCS) have sought to integrate the body of knowledge (BOK) in their curricula. This article reports on a study assessing the familiarity of Historically Black College and University (HBCU) students with the FCS-BOK by their major (specialized area) and classification…
AAFCS Accreditation: From Dream to Reality at Jacksonville State University

ERIC Educational Resources Information Center

Goodwin, Debra K.; Roberts, W. Tim; Boggs, Robbie; Townsel, Kim; Frazier, Jeannie; Marsh, Jill

2014-01-01

Accreditation by the American Association of Family and Consumer Sciences (AAFCS) was a long-held dream of the Family and Consumer Sciences (FCS) Unit at Jacksonville State University in Alabama. After more than 6 decades of preparing FCS students for life and the workplace, the FCS Unit resolutely began the journey to the coveted and honored…
Predictive display design for the vehicles with time delay in dynamic response

NASA Astrophysics Data System (ADS)

Efremov, A. V.; Tiaglik, M. S.; Irgaleev, I. H.; Efremov, E. V.

2018-02-01

The two ways for the improvement of flying qualities are considered: the predictive display (PD) and the predictive display integrated with the flight control system (FCS). The both ways allow to transforming the controlled element dynamics in the crossover frequency range, to improve the accuracy of tracking and to suppress the effect of time delay in the vehicle response too. The technique for optimization of the predictive law is applied to the landing task. The results of the mathematical modeling and experimental investigations carried out for this task are considered in the paper.
[Free crystalline silica: a comparison of methods for its determination in total dust].

PubMed

Maciejewska, Aleksandra; Szadkowska-Stańczyk, Irena; Kondratowicz, Grzegorz

2005-01-01

The major objective of the study was to compare and investigate the usefulness of quantitative analyses of free crystalline silica (FCS) in the assessment of dust exposure in samples of total dust of varied composition, using three methods: chemical method in common use in Poland; infrared spectrometry; and x-ray powder diffraction. Mineral composition and FCS contents were investigated in 9 laboratory samples of raw materials, materials, and industrial wastes, containing from about 2 to over 80% of crystalline silica and reduced to particles of size corresponding with that of total dust. Sample components were identified using XRD and FT-IR methods. Ten independent determinations of FCS with each of the three study methods were performed in dust samples. An analysis of linear correlation was applied to investigate interrelationship between mean FCS determinations. In analyzed dust samples, along with silica dust there were numerous minerals interfering with silica during the quantitative analysis. Comparison of mean results of FCS determinations showed that the results obtained using the FT-IR method were by 12-13% lower than those obtained with two other methods. However, the differences observed were within the limits of changeability of results associated with their precision and dependence on reference materials used. Assessment of occupational exposure to dusts containing crystalline silica can be performed on the basis of quantitative analysis of FCS in total dusts using each of the compared methods. The FT-IR method is most appropriate for the FCS determination in samples of small amount of silica or collected at low dust concentrations; the XRD method for the analysis of multicomponent samples; and the chemical method in the case of medium and high FCS contents in samples or high concentrations of dusts in the work environment.
Forskolin effect on the cryosurvival of in vitro-produced bovine embryos in the presence or absence of fetal calf serum.

PubMed

Paschoal, Daniela Martins; Sudano, Mateus José; Guastali, Midyan Daroz; Dias Maziero, Rosiára Rosária; Crocomo, Letícia Ferrari; Oña Magalhães, Luis Carlos; da Silva Rascado, Tatiana; Martins, Alicio; da Cruz Landim-Alvarenga, Fernanda

2014-05-01

The objective of this study was to assess the viability and cryotolerance of zebu embryos produced in vitro with or without the addition of fetal calf serum (FCS) and forskolin (F). Embryos produced in vivo were used as a control. Presumptive zygotes were cultured in modified synthetic oviductal fluid supplemented with amino acids (SOFaa), bovine serum albumin (BSA) and with (2.5%) or without (0%) FCS. On day 6 of growth, the embryos from each group were divided into treatments with or without 10 μM F to induce embryonic lipolysis, comprising a total of four experimental groups: 2.5% FCS, 0% FCS, 2.5% + F and 0% + F. For vitrification, embryos were exposed to vitrification solution 1 (5 M EG (ethylene glycol)) for 3 min and then transferred to vitrification solution 2 (7 M EG, 0.5 M galactose solution and 18% (w/v) Ficoll 70) before being introduced to liquid nitrogen. The presence of FCS in the culture medium resulted in the production of embryos with a similar rate of damaged cells compared with in vivo-produced embryos. After vitrification, the 2.5% FCS group had a significantly higher rate of damaged cells when compared with the other groups (P < 0.05). The results of this experiment indicated that the omission of FCS and the addition of forskolin do not have deleterious effect on embryo production rates. In addition, embryos produced in the presence of FCS had greater sensitivity to cryopreservation, but this effect was reversed when forskolin was added to the medium, which improved embryo survival without affecting embryo development and quality after vitrification.
Fluorescence correlation spectroscopy: novel variations of an established technique.

PubMed

Haustein, Elke; Schwille, Petra

2007-01-01

Fluorescence correlation spectroscopy (FCS) is one of the major biophysical techniques used for unraveling molecular interactions in vitro and in vivo. It allows minimally invasive study of dynamic processes in biological specimens with extremely high temporal and spatial resolution. By recording and correlating the fluorescence fluctuations of single labeled molecules through the exciting laser beam, FCS gives information on molecular mobility and photophysical and photochemical reactions. By using dual-color fluorescence cross-correlation, highly specific binding studies can be performed. These have been extended to four reaction partners accessible by multicolor applications. Alternative detection schemes shift accessible time frames to slower processes (e.g., scanning FCS) or higher concentrations (e.g., TIR-FCS). Despite its long tradition, FCS is by no means dated. Rather, it has proven to be a highly versatile technique that can easily be adapted to solve specific biological questions, and it continues to find exciting applications in biology and medicine.
White Matter Microstructure in Transsexuals and Controls Investigated by Diffusion Tensor Imaging

PubMed Central

Kranz, Georg S.; Hahn, Andreas; Kaufmann, Ulrike; Küblböck, Martin; Hummer, Allan; Ganger, Sebastian; Seiger, Rene; Winkler, Dietmar; Swaab, Dick F.; Windischberger, Christian; Kasper, Siegfried; Lanzenberger, Rupert

2015-01-01

Biological causes underpinning the well known gender dimorphisms in human behavior, cognition, and emotion have received increased attention in recent years. The advent of diffusion-weighted magnetic resonance imaging has permitted the investigation of the white matter microstructure in unprecedented detail. Here, we aimed to study the potential influences of biological sex, gender identity, sex hormones, and sexual orientation on white matter microstructure by investigating transsexuals and healthy controls using diffusion tensor imaging (DTI). Twenty-three female-to-male (FtM) and 21 male-to-female (MtF) transsexuals, as well as 23 female (FC) and 22 male (MC) controls underwent DTI at 3 tesla. Fractional anisotropy, axial, radial, and mean diffusivity were calculated using tract-based spatial statistics (TBSS) and fiber tractography. Results showed widespread significant differences in mean diffusivity between groups in almost all white matter tracts. FCs had highest mean diffusivities, followed by FtM transsexuals with lower values, MtF transsexuals with further reduced values, and MCs with lowest values. Investigating axial and radial diffusivities showed that a transition in axial diffusivity accounted for mean diffusivity results. No significant differences in fractional anisotropy maps were found between groups. Plasma testosterone levels were strongly correlated with mean, axial, and radial diffusivities. However, controlling for individual estradiol, testosterone, or progesterone plasma levels or for subjects’ sexual orientation did not change group differences. Our data harmonize with the hypothesis that fiber tract development is influenced by the hormonal environment during late prenatal and early postnatal brain development. PMID:25392513
Vitality and Ethnolinguistic Attitudes of Acadians, Franco-Ontarians and Francophone Quebecers: Two or Three Solitudes in Canada's Bilingual Belt?

ERIC Educational Resources Information Center

Sioufi, Rana; Bourhis, Richard Y.; Allard, Réal

2016-01-01

Do French-Canadian (FC) minorities in New Brunswick and Ontario remain as committed as majority Francophone Quebecers in developing their vitality within Canada's bilingual belt? FCs constitute host communities for interprovincial migrants of FC and English-Canadian (EC) background who can bolster or weaken the vitality of FCs. How FCs and ECs…
Altered Coupling Between Resting-State Cerebral Blood Flow and Functional Connectivity in Schizophrenia.

PubMed

Zhu, Jiajia; Zhuo, Chuanjun; Xu, Lixue; Liu, Feng; Qin, Wen; Yu, Chunshui

2017-10-21

Respective changes in resting-state cerebral blood flow (CBF) and functional connectivity in schizophrenia have been reported. However, their coupling alterations in schizophrenia remain largely unknown. 89 schizophrenia patients and 90 sex- and age-matched healthy controls underwent resting-state functional MRI to calculate functional connectivity strength (FCS) and arterial spin labeling imaging to compute CBF. The CBF-FCS coupling of the whole gray matter and the CBF/FCS ratio (the amount of blood supply per unit of connectivity strength) of each voxel were compared between the 2 groups. Whole gray matter CBF-FCS coupling was decreased in schizophrenia patients relative to healthy controls. In schizophrenia patients, the decreased CBF/FCS ratio was predominantly located in cognitive- and emotional-related brain regions, including the dorsolateral prefrontal cortex, insula, hippocampus and thalamus, whereas an increased CBF/FCS ratio was mainly identified in the sensorimotor regions, including the putamen, and sensorimotor, mid-cingulate and visual cortices. These findings suggest that the neurovascular decoupling in the brain may be a possible neuropathological mechanism of schizophrenia. © The Author 2017. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com
Altered Functional Connectivity of Cognitive-Related Cerebellar Subregions in Alzheimer’s Disease

PubMed Central

Zheng, Weimin; Liu, Xingyun; Song, Haiqing; Li, Kuncheng; Wang, Zhiqun

2017-01-01

Alzheimer’s disease (AD) is the most common cause of dementia. Previous studies have found disrupted resting state functional connectivities (rsFCs) in various brain networks in the AD patients. However, few studies have focused on the rsFCs of the cerebellum and its sub-regions in the AD patients. In this study, we collected resting-state functional magnetic resonance imaging (rs-fMRI) data including 32 AD patients and 38 healthy controls (HCs). We selected two cognitive-related subregions of the cerebellum as seed region and mapped the whole-brain rsFCs for each subregion. We identified several distinct rsFC patterns of the two cognitive-related cerebellar subregions: default-mode network (DMN), frontoparietal network (FPN), visual network (VN) and sensorimotor network (SMN). Compared with the controls, the AD patients showed disrupted rsFCs in several different networks (DMN, VN and SMN), predicting the impairment of the functional integration in the cerebellum. Notably, these abnormal rsFCs of the two cerebellar subregions were closely associated with cognitive performance. Collectively, we demonstrated the distinct rsFCs patterns of cerebellar sub-regions with various functional networks, which were differentially impaired in the AD patients. PMID:28559843
In vitro culture of bovine embryos in murine ES cell conditioned media negatively affects expression of pluripotency-related markers OCT4, SOX2 and SSEA1.

PubMed

Oliveira, C S; de Souza, M M; Saraiva, N Z; Tetzner, T A D; Lima, M R; Lopes, F L; Garcia, J M

2012-06-01

Despite extensive efforts, establishment of bovine embryonic stem (ES) cell lines has not been successful. We hypothesized that culture conditions for in vitro-produced (IVP) embryos, the most used source of inner cell mass (ICM) to obtain ES cells, might affect their undifferentiated state. Therefore, the aim of this work was to improve pluripotency of IVP blastocysts to produce suitable ICM for further culturing. We tested KSR and foetal calf serum (FCS) supplements in SOF medium and ES cell conditioned medium (CM) on IVC (groups: KSR, KSR CM, FCS and FCS CM). Cleavage and blastocyst rates were similar between all groups. Also, embryonic quality, assessed by apoptosis rates (TUNEL assay), total cell number and ICM percentage did not differ between experimental groups. However, expression of pluripotency-related markers was affected. We detected down-regulation of OCT3/4, SOX2 and SSEA1 in ICM of FCS CM blastocysts (p < 0.05). SOX2 gene expression revealed lower levels (p < 0.05) on KSR CM blastocysts and a remarkable variation in SOX2 mRNA levels on FCS-supplemented blastocysts. In conclusion, pluripotency-related markers tend to decrease after supplementation with ES cell CM, suggesting different mechanisms regulating mouse and bovine pluripotency. KSR supplementation did not differ from FCS, but FCS replacement by KSR may produce blastocysts with stable SOX2 gene expression levels. © 2011 Blackwell Verlag GmbH.
Fluorescence correlation spectroscopy, Raster image correlation spectroscopy and Number & Brightness on a commercial confocal laser scanning microscope with analog detectors (Nikon C1)

PubMed Central

Moens, Pierre D.J.; Gratton, Enrico; Salvemini, Iyrri L.

2010-01-01

Fluorescence correlation spectroscopy (FCS) was developed in 1972 by Magde, Elson and Webb (Magde et al., 1972). Photon counting detectors and avalanche photodiodes have become standards in FCS to the point that there is a widespread belief that these detectors are essential to perform FCS experiments, despite the fact that FCS was developed using analog detectors. Spatial and temporal intensity fluctuation correlations using analog detection on a commercial Olympus Fluoview 300 microscope has been reported by Brown et al. (2008). However, each analog instrument has its own idiosyncrasies that need to be understood before using the instrument for FCS. In this work we explore the capabilities of the Nikon C1, a low cost confocal microscope, to obtain single point FCS, Raster-scan Image Correlation Spectroscopy (RICS) and Number & Brightness data both in solution and incorporated into the membrane of Giant Unilamellar Vesicles (GUVs). We show that it is possible to obtain dynamic information about fluorescent molecules from single point FCS, RICS and Number & Brightness using the Nikon C1. We highlighted the fact that care should be taken in selecting the acquisition parameters in order to avoid possible artifacts due to the detector noise. However, due to relatively large errors in determining the distribution of digital levels for a given microscope setting, the system is probably only adequate for determining relative brightness within the same image. PMID:20734406
Ozzie and Harriet Never Were: A Century Review of Family and Consumer Sciences and the Changing American Family

ERIC Educational Resources Information Center

Allen, Kimberly I.; Dunn, Carolyn; Zaslow, Sandra

2011-01-01

As North Carolina FCS celebrates its 100-year centennial, it is time to reflect. For a century, FCS professionals have helped families apply research-based knowledge and principles. This article describes how American families have changed and how we have met those changes in our Extension roles. We also challenge FCS professionals to view the…
A proposed origin for fossilized Pennsylvanian plant cuticles by pyrite oxidation (Sydney Coalfield, Nova Scotia, Canada)

USGS Publications Warehouse

Zodrow, E.L.; Mastalerz, Maria

2009-01-01

Fossilized cuticles, though rare in the roof rocks of coal seam in the younger part of the Pennsylvanian Sydney Coalfield, Nova Scotia, represent nearly all of the major plant groups. Selected for investigation, by methods of Fourier transform infrared spectroscopy (FTIR) and elemental analysis, are fossilized cuticles (FCs) and cuticles extracted from compressions by Schulze's process (CCs) of Alethopteris ambigua. These investigations are supplemented by FTIR analysis of FCs and CCs of Cordaites principalis, and a cuticle-fossilized medullosalean(?) axis. The purpose of this study is threefold: (1) to try to determine biochemical discriminators between FCs and CCs of the same species using semi-quantitative FTIR techniques; (2) to assess the effects chemical treatments have, particularly Schulze's process, on functional groups; and most importantly (3) to study the primary origin of FCs. Results are equivocal in respect to (1); (2) after Schulze's treatment aliphatic moieties tend to be reduced relative to oxygenated groups, and some aliphatic chains may be shortened; and (3) a primary chemical model is proposed. The model is based on a variety of geological observations, including stratal distribution, clay and pyrite mineralogies associated with FCs and compressions, and regional geological structure. The model presupposes compression-cuticle fossilization under anoxic conditions for late authigenic deposition of sub-micron-sized pyrite on the compressions. Rock joints subsequently provided conduits for oxygen-enriched ground-water circulation to initiate in situ pyritic oxidation that produced sulfuric acid for macerating compressions, with resultant loss of vitrinite, but with preservation of cuticles as FCs. The timing of the process remains undetermined, though it is assumed to be late to post-diagenetic. Although FCs represent a pathway of organic matter transformation (pomd) distinct from other plant-fossilization processes, global applicability of the chemical models remains to be tested. CCs and FCs are inferred endpoints on a spectrum of pomd which complicates assessing origin of in-between transformations (partially macerated cuticles). FCs index highly acidic levels that existed locally in the roof rocks.

Scanning fluorescence correlation spectroscopy comes full circle.

PubMed

Gunther, German; Jameson, David M; Aguilar, Joao; Sánchez, Susana A

2018-02-07

In this article, we review the application of fluorescence correlation spectroscopy (FCS) methods to studies on live cells. We begin with a brief overview of the theory underlying FCS, highlighting the type of information obtainable. We then focus on circular scanning FCS. Specifically, we discuss instrumentation and data analysis and offer some considerations regarding sample preparation. Two examples from the literature are discussed in detail. First, we show how this method, coupled with the photon counting histogram analysis, can provide information on yeast ribosomal structures in live cells. The combination of scanning FCS with dual channel detection in the study of lipid domains in live cells is also illustrated. Copyright © 2018 Elsevier Inc. All rights reserved.
Fluorescence Correlation Spectroscopy at Micromolar Concentrations without Optical Nanoconfinement

DOE PAGES

Laurence, Ted A.; Ly, Sonny; Bourguet, Feliza; ...

2014-08-14

Fluorescence correlation spectroscopy (FCS) is an important technique for studying biochemical interactions dynamically that may be used in vitro and in cell-based studies. It is generally claimed that FCS may only be used at nM concentrations. We show that this general consensus is incorrect and that the limitation to nM concentrations is not fundamental but due to detector limits as well as laser fluctuations. With a high count rate detector system and applying laser fluctuation corrections, we demonstrate FCS measurements up to 38 μM with the same signal-to-noise as at lower concentrations. Optical nanoconfinement approaches previously used to increase themore » concentration range of FCS are not necessary, and further increases above 38 μM may be expected using detectors and detector arrays with higher saturation rates and better laser fluctuation corrections. This approach greatly widens the possibilities of dynamic measurements of biochemical interactions using FCS at physiological concentrations.« less
In Vivo Fluorescence Correlation and Cross-Correlation Spectroscopy

NASA Astrophysics Data System (ADS)

Mütze, Jörg; Ohrt, Thomas; Petrášek, Zdeněk; Schwille, Petra

In this manuscript, we describe the application of Fluorescence Correlation Spectroscopy (FCS), Fluorescence Cross-Correlation Spectroscopy (FCCS), and scanning FCS (sFCS) to two in vivo systems. In the first part, we describe the application of two-photon standard and scanning FCS in Caenorhabditis elegans embryos. The differentiation of a single fertilized egg into a complex organism in C. elegans is regulated by a number of protein-dependent processes. The oocyte divides asymmetrically into two daughter cells of different developmental fate. Two of the involved proteins, PAR-2 and NMY-2, are studied. The second investigated system is the mechanism of RNA interference in human cells. An EGFP based cell line that allows to study the dynamics and localization of the RNA-induced silencing complex (RISC) with FCS in vivo is created, which has so far been inaccessible with other experimental methods. Furthermore, Fluorescence Cross-Correlation Spectroscopy is employed to highlight the asymmetric incorporation of labeled siRNAs into RISC.
Generation of immunosuppressive mesenchymal stem cells in allogeneic human serum.

PubMed

Le Blanc, Katarina; Samuelsson, Håkan; Lönnies, Lena; Sundin, Mikael; Ringdén, Olle

2007-10-27

Mesenchymal stem cells (MSC) may be used to treat acute graft-versus-host disease and for tissue repair. In vitro expansion of MSC has been achieved in the presence of fetal calf serum (FCS). For safety and regulatory reasons, we explored if FCS could be replaced by human blood group AB serum. Proliferation and fold increase of MSC was higher in the presence of AB-serum, compared to FCS. Similar to cells generated in FCS media, MSC from AB-serum media were more than 95% positive for CD90, CD105 and human leukocyte antigen (HLA) class I, and negative for hematopoietic and endothelial markers CD14, CD31, CD34, CD45, and CD80. HLA class II expression was higher in MSC generated in AB-serum, but decreased with higher passage numbers. MSC generated in AB-serum suppressed lymphocyte proliferation in mixed lymphocyte cultures and after stimulation with phytohemagglutinin. MSC expanded in AB-serum and FCS have similar in vitro properties.
Two-colored fluorescence correlation spectroscopy screening for LC3-P62 interaction inhibitors.

PubMed

Tsuganezawa, Keiko; Shinohara, Yoshiyasu; Ogawa, Naoko; Tsuboi, Shun; Okada, Norihisa; Mori, Masumi; Yokoyama, Shigeyuki; Noda, Nobuo N; Inagaki, Fuyuhiko; Ohsumi, Yoshinori; Tanaka, Akiko

2013-10-01

The fluorescence correlation spectroscopy (FCS)-based competitive binding assay to screen for protein-protein interaction inhibitors is a highly sensitive method as compared with the fluorescent polarization assay used conventionally. However, the FCS assay identifies many false-positive compounds, which requires specifically designed orthogonal screenings. A two-colored application of the FCS-based screening was newly developed, and inhibitors of a protein-protein interaction, involving selective autophagy, were selected. We focused on the interaction of LC3 with the adaptor protein p62, because the interaction is crucial to degrade the specific target proteins recruited by p62. First, about 10,000 compounds were subjected to the FCS-based competitive assay using a TAMRA-labeled p62-derived probe, and 29 hit compounds were selected. Next, the obtained hits were evaluated by the second FCS assay, using an Alexa647-labeled p62-derived probe to remove the false-positive compounds, and six hit compounds inhibited the interaction. Finally, we tested all 29 compounds by surface plasmon resonance-based competitive binding assay to evaluate their inhibition of the LC3-p62 interaction and selected two inhibitors with IC50 values less than 2 µM. The two-colored FCS-based screening was shown to be effective to screen for protein-protein interaction inhibitors.
A Descriptive Study of Decision-Making Conversations during Pediatric Intensive Care Unit Family Conferences.

PubMed

Smith, Michael A; Clayman, Marla L; Frader, Joel; Arenson, Melanie; Haber-Barker, Natalie; Ryan, Claire; Emanuel, Linda; Michelson, Kelly

2018-06-19

Little is known about how decision-making conversations occur during pediatric intensive care unit (PICU) family conferences (FCs). Describe the decision-making process and implementation of shared decision making (SDM) during PICU FCs. Observational study. University-based tertiary care PICU, including 31 parents and 94 PICU healthcare professionals involved in FCs. We recorded, transcribed, and analyzed 14 PICU FCs involving decision-making discussions. We used a modified grounded theory and content analysis approach to explore the use of traditionally described stages of decision making (DM) (information exchange, deliberation, and determining a plan). We also identified the presence or absence of predefined SDM elements. DM involved the following modified stages: information exchange; information-oriented deliberation; plan-oriented deliberation; and determining a plan. Conversations progressed through stages in a nonlinear manner. For the main decision discussed, all conferences included a presentation of the clinical issues, treatment alternatives, and uncertainty. A minority of FCs included assessing the family's understanding (21%), assessing the family's need for input from others (28%), exploring the family's desired decision-making role (35%), and eliciting the family's opinion (42%). In the FCs studied, we found that DM is a nonlinear process. We also found that several SDM elements that could provide information about parents' perspectives and needs did not always occur, identifying areas for process improvement.
Molecular dynamics and Monte Carlo simulations resolve apparent diffusion rate differences for proteins confined in nanochannels

DOE PAGES

Tringe, J. W.; Ileri, N.; Levie, H. W.; ...

2015-08-01

We use Molecular Dynamics and Monte Carlo simulations to examine molecular transport phenomena in nanochannels, explaining four orders of magnitude difference in wheat germ agglutinin (WGA) protein diffusion rates observed by fluorescence correlation spectroscopy (FCS) and by direct imaging of fluorescently-labeled proteins. We first use the ESPResSo Molecular Dynamics code to estimate the surface transport distance for neutral and charged proteins. We then employ a Monte Carlo model to calculate the paths of protein molecules on surfaces and in the bulk liquid transport medium. Our results show that the transport characteristics depend strongly on the degree of molecular surface coverage.more » Atomic force microscope characterization of surfaces exposed to WGA proteins for 1000 s show large protein aggregates consistent with the predicted coverage. These calculations and experiments provide useful insight into the details of molecular motion in confined geometries.« less
In vitro culture of human osteosarcoma cell lines: a comparison of functional characteristics for cell lines cultured in medium without and with fetal calf serum.

PubMed

Bruserud, Oystein; Tronstad, Karl Johan; Berge, Rolf

2005-06-01

Experimental in vitro models including well-characterised cell lines can be used to identify possible new therapeutic targets for the treatment of osteosarcoma. Culture media including inactivated serum is often recommended for in vitro culture of osteosarcoma cells, but the serum component then represents a nonstandardised parameter including a wide range of unidentified mediators. To improve the standardisation we have investigated whether serum-free culture media can be used in experimental in vitro studies of osteosarcoma cell lines. The seven osteosarcoma cell lines Cal72, SJSA-1, Saos-2, SK-ES-1, U2OS, 143.98.2, and KHOS-32IH were cultured in vitro in various serum-free media and media supplemented with 10% heat-inactivated fetal calf serum (FCS). Although proliferation often was relatively low in serum-free media (X-vivo 10, X-vivo 15, X-vivo 20, Stem Span SFEM), some cell lines (Cal72, KHOS-32IH, Saos-2) showed proliferation comparable with the recommended FCS-containing media even when using serum-free conditions. The optimal serum-free medium then varied between cell lines. We also compared 6 different FCS-containing media (including Stem Span with 10% FCS) and the optimal FCS-containing medium varied between cell lines. However, all cell lines proliferated well in Stem Span with FCS, and this medium was regarded as optimal for four of the lines. FCS could not be replaced by fatty acids or low density lipoprotein when testing the Stem Span medium. The release of a wide range of soluble mediators showed only minor differences when using serum-free and FCS-containing media (including Stem Span with and without FCS), and serum-free Stem Span could also be used for in vitro studies of mitogen-stimulated T cell activation in the presence of accessory osteosarcoma cells. The use of Stem Span with 10% FCS allowed the release of a wide range of chemokines by osteosarcoma cell lines (Cal72, SJSA-1), and the chemokine release profile was very similar to the fibroblast lines Hs27 and HFL1. Serum-free culture media can be used for in vitro studies of several osteosarcoma cell lines, but the optimal medium varies between cell lines and thus depends on: (i) the cell lines to be investigated/compared; (ii) the functional characteristic that is evaluated (proliferation, cytokine release); and (iii) whether coculture experiments are included.
Phospholipid Diffusion Coefficients of Cushioned Model Membranes determined via Z-Scan Fluorescence Correlation Spectroscopy

PubMed Central

Sterling, Sarah M.; Allgeyer, Edward S.; Fick, Jörg; Prudovsky, Igor; Mason, Michael D.; Neivandt, David J.

2013-01-01

Model cellular membranes enable the study of biological processes in a controlled environment and reduce the traditional challenges associated with live or fixed cell studies. However, model membrane systems based on the air/water or oil/solution interface do not allow for incorporation of transmembrane proteins, or for the study of protein transport mechanisms. Conversely, a phospholipid bilayer deposited via the Langmuir-Blodgett/Langmuir Schaefer method on a hydrogel layer is potentially an effective mimic of the cross-section of a biological membrane, and facilitates both protein incorporation and transport studies. Prior to application, however, such membranes must be fully characterized, particularly with respect to the phospholipid bilayer phase transition temperature. Here we present a detailed characterization of the phase transition temperature of the inner and outer leaflets of a chitosan supported model membrane system. Specifically, the lateral diffusion coefficient of each individual leaflet has been determined as a function of temperature. Measurements were performed utilizing z-scan fluorescence correlation spectroscopy (FCS), a technique that yields calibration-free diffusion information. Analysis via the method of Wawrezinieck and coworkers, revealed that phospholipid diffusion changes from raft-like to free diffusion as the temperature is increased; an insight into the dynamic behavior of hydrogel supported membranes not previously reported. PMID:23705855
Surface conservation laws at microscopically diffuse interfaces.

PubMed

Chu, Kevin T; Bazant, Martin Z

2007-11-01

In studies of interfaces with dynamic chemical composition, bulk and interfacial quantities are often coupled via surface conservation laws of excess surface quantities. While this approach is easily justified for microscopically sharp interfaces, its applicability in the context of microscopically diffuse interfaces is less theoretically well-established. Furthermore, surface conservation laws (and interfacial models in general) are often derived phenomenologically rather than systematically. In this article, we first provide a mathematically rigorous justification for surface conservation laws at diffuse interfaces based on an asymptotic analysis of transport processes in the boundary layer and derive general formulae for the surface and normal fluxes that appear in surface conservation laws. Next, we use nonequilibrium thermodynamics to formulate surface conservation laws in terms of chemical potentials and provide a method for systematically deriving the structure of the interfacial layer. Finally, we derive surface conservation laws for a few examples from diffusive and electrochemical transport.
White matter microstructure in transsexuals and controls investigated by diffusion tensor imaging.

PubMed

Kranz, Georg S; Hahn, Andreas; Kaufmann, Ulrike; Küblböck, Martin; Hummer, Allan; Ganger, Sebastian; Seiger, Rene; Winkler, Dietmar; Swaab, Dick F; Windischberger, Christian; Kasper, Siegfried; Lanzenberger, Rupert

2014-11-12

Biological causes underpinning the well known gender dimorphisms in human behavior, cognition, and emotion have received increased attention in recent years. The advent of diffusion-weighted magnetic resonance imaging has permitted the investigation of the white matter microstructure in unprecedented detail. Here, we aimed to study the potential influences of biological sex, gender identity, sex hormones, and sexual orientation on white matter microstructure by investigating transsexuals and healthy controls using diffusion tensor imaging (DTI). Twenty-three female-to-male (FtM) and 21 male-to-female (MtF) transsexuals, as well as 23 female (FC) and 22 male (MC) controls underwent DTI at 3 tesla. Fractional anisotropy, axial, radial, and mean diffusivity were calculated using tract-based spatial statistics (TBSS) and fiber tractography. Results showed widespread significant differences in mean diffusivity between groups in almost all white matter tracts. FCs had highest mean diffusivities, followed by FtM transsexuals with lower values, MtF transsexuals with further reduced values, and MCs with lowest values. Investigating axial and radial diffusivities showed that a transition in axial diffusivity accounted for mean diffusivity results. No significant differences in fractional anisotropy maps were found between groups. Plasma testosterone levels were strongly correlated with mean, axial, and radial diffusivities. However, controlling for individual estradiol, testosterone, or progesterone plasma levels or for subjects' sexual orientation did not change group differences. Our data harmonize with the hypothesis that fiber tract development is influenced by the hormonal environment during late prenatal and early postnatal brain development. Copyright © 2014 the authors 0270-6474/14/3415466-10$15.00/0.
Choosing the right fluorophore for single-molecule fluorescence studies in a lipid environment.

PubMed

Zhang, Zhenfu; Yomo, Dan; Gradinaru, Claudiu

2017-07-01

Nonspecific interactions between lipids and fluorophores can alter the outcomes of single-molecule spectroscopy of membrane proteins in live cells, liposomes or lipid nanodiscs and of cytosolic proteins encapsulated in liposomes or tethered to supported lipid bilayers. To gain insight into these effects, we examined interactions between 9 dyes that are commonly used as labels for single-molecule fluorescence (SMF) and 6 standard lipids including cationic, zwitterionic and anionic types. The diffusion coefficients of dyes in the absence and presence of set amounts of lipid vesicles were measured by fluorescence correlation spectroscopy (FCS). The partition coefficients and the free energies of partitioning for different fluorophore-lipid pairs were obtained by global fitting of the titration FCS curves. Lipids with different charges, head groups and degrees of chain saturation were investigated, and interactions with dyes are discussed in terms of hydrophobic, electrostatic and steric contributions. Fluorescence imaging of individual fluorophores adsorbed on supported lipid bilayers provides visualization and additional quantification of the strength of dye-lipid interaction in the context of single-molecule measurements. By dissecting fluorophore-lipid interactions, our study provides new insights into setting up single-molecule fluorescence spectroscopy experiments with minimal interference from interactions between fluorescent labels and lipids in the environment. Copyright © 2017 Elsevier B.V. All rights reserved.
A comparative study on fluorescent cholesterol analogs as versatile cellular reporters[S

PubMed Central

Sezgin, Erdinc; Can, Fatma Betul; Schneider, Falk; Clausen, Mathias P.; Galiani, Silvia; Stanly, Tess A.; Waithe, Dominic; Colaco, Alexandria; Honigmann, Alf; Wüstner, Daniel; Platt, Frances; Eggeling, Christian

2016-01-01

Cholesterol (Chol) is a crucial component of cellular membranes, but knowledge of its intracellular dynamics is scarce. Thus, it is of utmost interest to develop tools for visualization of Chol organization and dynamics in cells and tissues. For this purpose, many studies make use of fluorescently labeled Chol analogs. Unfortunately, the introduction of the label may influence the characteristics of the analog, such as its localization, interaction, and trafficking in cells; hence, it is important to get knowledge of such bias. In this report, we compared different fluorescent lipid analogs for their performance in cellular assays: 1) plasma membrane incorporation, specifically the preference for more ordered membrane environments in phase-separated giant unilamellar vesicles and giant plasma membrane vesicles; 2) cellular trafficking, specifically subcellular localization in Niemann-Pick type C disease cells; and 3) applicability in fluorescence correlation spectroscopy (FCS)-based and super-resolution stimulated emission depletion-FCS-based measurements of membrane diffusion dynamics. The analogs exhibited strong differences, with some indicating positive performance in the membrane-based experiments and others in the intracellular trafficking assay. However, none showed positive performance in all assays. Our results constitute a concise guide for the careful use of fluorescent Chol analogs in visualizing cellular Chol dynamics. PMID:26701325
Stabilization of hyperforin dicyclohexylammonium salt with dissolved albumin and albumin nanoparticles for studying hyperforin effects on 2D cultivation of keratinocytes in vitro.

PubMed

Füller, J; Kellner, T; Gaid, M; Beerhues, L; Müller-Goymann, C C

2018-05-01

Due to the limited chemical stability of the natural hyperforin molecule, a more stable form of hyperforin, i.e., the hyperforin dicyclohexylammonium salt (HYP-DCHA) has been used for ex vivo and in vitro experiments in recent years, but its actual stability under typical cell culture conditions has never been studied before. In this contribution the stability of HYP-DCHA was examined under typical cell culture conditions. Different cell culture media with and without fetal calf serum (FCS) supplementation were studied with regard to further stabilization of HYP-DCHA determined with HPLC analysis. Furthermore, albumin nanoparticles were examined as a stabilizing carrier system for HYP-DCHA. In this context, the interaction between HYP-DCHA and albumin nanoparticles (ANP) was examined with regard to size and loading with HYP . The effects of HYP-DCHA either supplied in cell culture medium or loaded on ANP on viability and cytotoxicity were studied in vitro on HaCaT monolayers (human keratinocyte cell line). HYP-DCHA supplied in FCS-containing medium was recovered completely after 24h of incubation. However, a lack of FCS caused a total loss of HYP-DCHA after less than 24h incubation time. Supplying HYP-DCHA loaded on ANP in an FCS-free medium resulted in a recovery of about 60% after 24h incubation. HYP-DCHA supplied in medium along with FCS showed a slow dose-dependent decrease in viability of HaCaT cells without any cytotoxic effects (antiproliferative effect). Treatment with HYP-DCHA with a lack of FCS resulted in a significantly faster decrease in viability which was mainly due to cytotoxicity. The latter was true for HYP-DHCA-loaded ANP where increased cytotoxicity was observed despite the presence of FCS. The results show that the stability of the widely used HYP-DCHA is rather limited under cell culture conditions. Especially a lack of FCS leads to degradation and/or oxidation of HYP-DCHA probably causing an increased cytotoxicity. In contrast, FCS supplementation fairly stabilizes HYP-DCHA under cell culture conditions while albumin nanoparticles may serve the same stabilization purpose despite increasing cytotoxic effects onto the cells themselves. Copyright © 2017 Elsevier B.V. All rights reserved.
The effect of swab sample choice on the detection of avian influenza in apparently healthy wild ducks

USGS Publications Warehouse

Ip, Hon S.; Dusek, Robert J.; Heisey, Dennis M.

2012-01-01

Historically, avian influenza viruses have been isolated from cloacal swab specimens, but recent data suggest that the highly pathogenic avian influenza (HPAI) H5N1 virus can be better detected from respiratory tract specimens. To better understand how swab sample type affects the detection ability of low pathogenic avian influenza (LPAI) viruses we collected and tested four swab types: oropharyngeal swabs (OS), cloacal swabs (CS), the two swab types combined in the laboratory (LCS), and the two swab types combined in the field (FCS). A total of 1968 wild waterfowl were sampled by each of these four methods and tested for avian influenza virus using matrix gene reverse-transcription (RT)-PCR. The highest detection rate occurred with the FCS (4.3%) followed by the CS (4.0%). Although this difference did not achieve traditional statistical significance, Bayesian analysis indicated that FCS was superior to CS with an 82% probability. The detection rates for both the LCS (2.4%) and the OS (0.4%) were significantly different from the FCS. In addition, every swab type that was matrix RT-PCR positive was also tested for recovery of viable influenza virus. This protocol reduced the detection rate, but the ordering of swab types remained the same: 1.73% FCS, 1.42% CS, 0.81% LCS, and 0% OS. Our data suggest that the FCS performed at least as well as any other swab type for detecting LPAI viruses in the wild ducks tested. When considering recent studies showing that HPAI H5N1 can be better detected in the respiratory tract, the FCS is the most appropriate sample to collect for HPAI H5N1 surveillance while not compromising LPAI studies.
The Effect of Cancer Patients' and Their Family Caregivers' Physical and Emotional Symptoms on Caregiver Burden.

PubMed

Johansen, Safora; Cvancarova, Milada; Ruland, Cornelia

Although there is significant evidence that the family caregivers (FCs) of cancer patients can experience significant caregiver burden and symptoms, less is known about the relationships between FCs and patient characteristics that influence caregiver burden. The purpose of this study was to examine the effect of cancer patients' and FCs' symptoms and demographic characteristics on caregiver burden at initiation of the patients' radiation treatment. Two hundred eighty-one dyads of FCs and cancer patients who received a diagnosis of breast, prostate, melanoma, lymphoma, and head and neck cancers were recruited at the beginning of the patients' radiation treatment. Measures of depression, sleep disturbance, fatigue, social support, and self-efficacy were obtained from both FCs and cancer patients. The family caregivers were also assessed for caregiver burden. Associations between patients' and caregivers' symptoms and demographic characteristics and caregiver burden were investigated using multivariate analyses. There were significant associations between caregiver burden and the patient-related variables such as self-efficacy (P = .02), sleep disturbance (P = .03), and social support (P = .04). Among FC-related variables, higher scores of depression (P < .01), fatigue (P < .01), and symptoms (P < .01) were significantly associated with higher caregiver burden. Being a female, either as a patient or FC, increased the likelihood of experiencing fatigue and sleep disturbance. Caregiver burden in FCs is influenced by interplay of patients' and their own symptoms and problems. These interdependencies exist from the beginning of treatment. Nurses should systematically assess the problems and symptoms of the patients and FCs and support them from the time of diagnosis to help prevent symptom development and deterioration.
Evaluation of family-centred services from parents of Chinese children with cerebral palsy with the Measure of Processes of Care.

PubMed

Wang, M; Petrini, M A; Guan, Q

2015-05-01

Family-centred service (FCS) has become essential to parents of children with cerebral palsy (CP) and professionals in Chinese paediatric rehabilitation services. FCS practice meets the unique needs of the child and family, through facilitation of optimal service provision delivered by professionals, and ensures service systems to be flexible, appropriate and actively responsive to the family needs. Parents used the Measure of Processes of Care 20 (MPOC-20) questionnaire to evaluate and verify the efficacy of use in China. The aims of the present study were twofold: to assess the validity and reliability of the Chinese MPOC-20, and investigate the range of parents' satisfaction with service provision in an FCS practice using the MPOC-20. The Chinese MPOC-20 was selected to assess parent satisfaction with service provision of professionals in FCS practice. Participants were parents of children under 8 years of age with CP, who had received rehabilitation services between May 2012 and May 2013, and were receiving rehabilitation services in May 2013 at a hospital outpatient department and a rehabilitation centre. The reliability and validity of the Chinese MPOC-20 were confirmed. Parents evaluated FCS practice with the MPOC-20 survey. Respectful and supportive care was rated with the highest score and providing general information the lowest. Parents according to the data were dissatisfied with the lack of information. Parents fairly evaluated service provision of professionals in FCS practice with the Chinese MPOC-20. Professionals received feedback reports of parents, summaries of the inadequacy of service delivery, and developed and implemented ameliorated measures in the FCS policy to strive to provide exemplary service. © 2014 John Wiley & Sons Ltd.
Evaluation of family-centred practices in the early intervention programmes for infants and young children in Singapore with Measure of Processes of Care for Service Providers and Measure of Beliefs about Participation in Family-Centred Service.

PubMed

Tang, H N; Chong, W H; Goh, W; Chan, W P; Choo, S

2012-01-01

The primary purpose of this study was to report on an evaluation of the perceptions and beliefs of service providers towards family-centred practices in 11 early intervention programmes for infants and young children in Singapore. The Measure of Processes of Care for Service Providers (MPOC-SP) and Measure of Beliefs about Participation in Family-Centred Service (MBP-FCS) were administered to 213 service providers made up of teachers, therapists, psychologists and social workers providing centre-based therapy to children with special needs who were below the age of 6 years. Exploratory factor analyses were performed with both scales. Nineteen of the 27 MPOC-SP items were retained and supported the original four-factor structure model. The exploratory factor analyses on MBP-FCS provided a less satisfactory outcome. Fourteen of the 28 items were retained and these loaded onto four factors. The two factors relating to Beliefs about benefits of FCS and Beliefs about the absence of negative outcomes from FCS failed to emerge as separate factors. Further multiple regressions indicated that more direct work with families and positive self-efficacy in implementing FCS contributed significantly to explaining service providers' positive perception towards family-centred practice in service delivery. This is the first time MPOC-SP and MBP-FCS were administered to a population in an Asian context. While MBP-FCS would benefit from further development work on its construct, MPOC-SP offered important insights into service providers' perspectives about family-centred practices that would have useful implications for professional and service development. © 2011 Blackwell Publishing Ltd.
Bifunctional capsular dosage form: novel fanicular cylindrical gastroretentive system of clarithromycin and immediate release granules of ranitidine HCl for simultaneous delivery.

PubMed

Rajput, Pallavi; Singh, Deshvir; Pathak, Kamla

2014-01-30

The study was aimed to develop a bifunctional single unit capsular system containing gastroretentive funicular cylindrical system (FCS) for controlled local delivery of clarithromycin and immediate release of ranitidine HCl. A 2(3) full factorial design was used to prepare gastroretentive FCS of clarithromycin using polyacrylamide (PAM), HPMC E15LV and Carbopol 934 P. The FCSs were evaluated for % cumulative drug release, floating time and in vitro detachment stress. Among the eight formulations, FCS5 (containing PAM and Carbopol 934 P at high and HPMC E15LV at low levels) showed % cumulative drug release of 97.09±1.14% in 8 h, floating time of 3 h and detachment stress of 8303.64±0.34 dynes/cm(2). Evaluation of optimized FCS by novel dynamic in vitro test proved superior bioadhesivity than cylindrical system under aggressive simulated peristaltic activity. Magnetic resonance imaging elucidated zero order release via constant swelling and erosion of FCS5. In vitro permeability across gastric mucin ensured its potential for effective eradication of deep seated Helicobactor pylori in gastric linings. The optimized FCS was combined with immediate release granules of rantidine HCl to get a bifunctional capsular dosage form. In vitro simultaneous drug release of clarithromycin and rantidine estimated by Vierordt's method exhibited a controlled drug release of 97.72±0.4% in 8 h for clarithromycin through FCS5 and 98.8±1.2% in 60 min from IR granules of ranitidine HCl. The novel system thus established its capability of simultaneous variable delivery of acid suppression agent and macrolide antibiotic that can be advantageous in clinical setting. Copyright © 2013 Elsevier B.V. All rights reserved.
Cell-type specific short-term plasticity at auditory nerve synapses controls feed-forward inhibition in the dorsal cochlear nucleus.

PubMed

Sedlacek, Miloslav; Brenowitz, Stephan D

2014-01-01

Feed-forward inhibition (FFI) represents a powerful mechanism by which control of the timing and fidelity of action potentials in local synaptic circuits of various brain regions is achieved. In the cochlear nucleus, the auditory nerve provides excitation to both principal neurons and inhibitory interneurons. Here, we investigated the synaptic circuit associated with fusiform cells (FCs), principal neurons of the dorsal cochlear nucleus (DCN) that receive excitation from auditory nerve fibers and inhibition from tuberculoventral cells (TVCs) on their basal dendrites in the deep layer of DCN. Despite the importance of these inputs in regulating fusiform cell firing behavior, the mechanisms determining the balance of excitation and FFI in this circuit are not well understood. Therefore, we examined the timing and plasticity of auditory nerve driven FFI onto FCs. We find that in some FCs, excitatory and inhibitory components of FFI had the same stimulation thresholds indicating they could be triggered by activation of the same fibers. In other FCs, excitation and inhibition exhibit different stimulus thresholds, suggesting FCs and TVCs might be activated by different sets of fibers. In addition, we find that during repetitive activation, synapses formed by the auditory nerve onto TVCs and FCs exhibit distinct modes of short-term plasticity. Feed-forward inhibitory post-synaptic currents (IPSCs) in FCs exhibit short-term depression because of prominent synaptic depression at the auditory nerve-TVC synapse. Depression of this feedforward inhibitory input causes a shift in the balance of fusiform cell synaptic input towards greater excitation and suggests that fusiform cell spike output will be enhanced by physiological patterns of auditory nerve activity.

Risk factors associated with cognitions for late-onset depression based on anterior and posterior default mode sub-networks.

PubMed

Liu, Rui; Yue, Yingying; Hou, Zhenghua; Yuan, Yonggui; Wang, Qiao

2018-08-01

Abnormal functional connectivity (FC) in the default mode network (DMN) plays an important role in late-onset depression (LOD) patients. In this study, the risk predictors of LOD based on anterior and posterior DMN are explored. A total of 27 LOD patients and 40 healthy controls (HC) underwent resting-state functional magnetic resonance imaging and cognitive assessments. Firstly, FCs within DMN sub-networks were determined by placing seeds in the ventral medial prefrontal cortex (vmPFC) and posterior cingulate cortex (PCC). Secondly, multivariable logistic regression was used to identify risk factors for LOD patients. Finally, correlation analysis was performed to investigate the relationship between risk factors and the cognitive value. Multivariable logistic regression showed that the FCs between the vmPFC and right middle temporal gyrus (MTG) (vmPFC-MTG_R), FCs between the vmPFC and left precuneus (PCu), and FCs between the PCC and left PCu (PCC-PCu_L) were the risk factors for LOD. Furthermore, FCs of the vmPFC-MTG_R and PCC-PCu_L correlated with processing speed (R = 0.35, P = 0.002; R = 0.32, P = 0.009), and FCs of the vmPFC-MTG_R correlated with semantic memory (R = 0.41, P = 0.001). The study was a cross-sectional study. The results may be potentially biased because of a small sample. In this study, we confirmed that LOD patients mainly present cognitive deficits in processing speed and semantic memory. Moreover, our findings further suggested that FCs within DMN sub-networks associated with cognitions were risk factors, which may be used for the prediction of LOD. Copyright © 2018 Elsevier B.V. All rights reserved.
Mapping the changed hubs and corresponding functional connectivity in idiopathic restless legs syndrome.

PubMed

Liu, Chunyan; Wang, Jiaojian; Hou, Yue; Qi, Zhigang; Wang, Li; Zhan, Shuqin; Wang, Rong; Wang, Yuping

2018-05-01

The hubs of the brain network play a key role in integrating and transferring information between different functional modules. However, whether the changed pattern in functional network hubs contributes to the onset of leg discomfort symptoms in restless legs syndrome (RLS) patients remains unclear. Using resting-state functional magnetic resonance imaging (rs-fMRI) and graph theory methods, we investigated whether alterations of hubs can be detected in RLS. First, we constructed the whole-brain voxelwise functional connectivity and calculated a functional connectivity strength (FCS) map in each of 16 drug-naive idiopathic RLS patients and 26 gender- and age-matched healthy control (HC) subjects. Next, a two-sample t test was applied to compare the FCS maps between HC and RLS patients, and to identify significant changes in FCS in RLS patients. To further elucidate the corresponding changes in the functional connectivity patterns of the aberrant hubs in RLS patients, whole-brain resting-state functional connectivity analyses for the hub areas were performed. The hub analysis revealed decreased FCS in the cuneus, fusiform gyrus, paracentral lobe, and precuneus, and increased FCS in the superior frontal gyrus and thalamus in idiopathic drug-naive RLS patients. Subsequent functional connectivity analyses revealed decreased functional connectivity in sensorimotor and visual processing networks and increased functional connectivity in the affective cognitive network and cerebellar-thalamic circuit. Furthermore, the mean FCS value in the superior frontal gyrus was significantly correlated with Hamilton Anxiety Rating Scale scores in RLS patients, and the mean FCS value in the fusiform gyrus was significantly correlated with Hamilton Depression Rating Scale scores. These findings may provide novel insight into the pathophysiology of RLS. Copyright © 2018 Elsevier B.V. All rights reserved.
The Army’s Future Combat System (FCS): Background and Issues for Congress

DTIC Science & Technology

2008-05-12

Operational Capability 2017 The full attainment of the capability to employ the system, including a fully manned, equipped, trained, and logistically...readiness crisis ,” and that “how FCS funding fits into that equation is yet to be determined.”24 Representative Murtha, Chairman of the House Appropriations...Oversight,” InsideDefense.com, May 7, 2008. 52 Ibid. 53 Ann Roosevelt, “FCS Incurs Schedule Breach, Operational Capability Slips to 2017 ,” Defense Daily
War experiences, general functioning and barriers to care among former child soldiers in Northern Uganda: the WAYS study.

PubMed

Amone-P'Olak, Kennedy; Jones, Peter; Meiser-Stedman, Richard; Abbott, Rosemary; Ayella-Ataro, Paul Stephen; Amone, Jackson; Ovuga, Emilio

2014-12-01

Exposure to war is associated with considerable risks for long-term mental health problems (MHP) and poor functioning. Yet little is known about functioning and mental health service (MHS) use among former child soldiers (FCS). We assessed whether different categories of war experiences predict functioning and perceived need for, sources of and barriers to MHS among FCS. Data were drawn from an on-going War-affected Youths (WAYS) cohort study of FCS in Uganda. Participants completed questionnaires about war experiences, functioning and perceived need for, sources of and barriers to MHS. Regression analyses and parametric tests were used to assess between-group differences. Deaths, material losses, threat to loved ones and sexual abuse significantly predicted poor functioning. FCS who received MHS function better than those who did not. Females reported more emotional and behavioural problems and needed MHS more than males. FCS who function poorly indicated more barriers to MHS than those who function well. Stigma, fear of family break-up and lack of health workers were identified as barriers to MHS. Various war experiences affect functioning differently. A significant need for MHS exists amidst barriers to MHS. Nevertheless, FCS are interested in receiving MHS and believe it would benefit them. © The Author 2014. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Perceptions of family-centred services in a paediatric rehabilitation programme: strengths and complexities from multiple stakeholders.

PubMed

Arcuri, G G; McMullan, A E; Murray, A E; Silver, L K; Bergthorson, M; Dahan-Oliel, N; Coutinho, F

2016-03-01

Family-centred services (FCS) are best practice in paediatric rehabilitation and describe philosophies and approaches to medical care that emphasize the partnership and involvement of parents. While evidence supports FCS, there are complexities to its successful implementation. This mixed-methods study aimed to measure the extent to which parents and the healthcare provider (HCP) perceive service provision as being family centred, and to describe barriers and facilitators to the delivery of FCS. Parents of children participating in a rehabilitation programme and HCPs providing services participated in this study. Parents completed the measure of processes of care-20 and participated in interviews, while HCPs completed the measure of processes of care-service providers and participated in a focus group. Quantitative analysis revealed that parents were mostly satisfied with features of FCS, which included communication and support between parents and HCPs, respect of diversity and parental collaboration and participation. Parents identified communication methods and psychosocial needs as areas that facilitated but sometimes detracted from FCS. Institutional barriers led to the identification of areas for improvement identified by multiple stakeholders. HCPs identified more areas for improvement than parents. When considering these barriers, it is evident that implementation is a complex process, impacted by institutional barriers. FCS needs to be investigated further, and systemic interventions should be used to facilitate its implementation. © 2015 John Wiley & Sons Ltd.
In vitro fermentation behaviors of fucosylated chondroitin sulfate from Pearsonothuria graeffei by human gut microflora.

PubMed

Wei, Chao-Yang; Liao, Ning-Bo; Zhang, Yu; Ye, Xing-Qian; Li, Shan; Hu, Ya-Qin; Liu, Dong-Hong; Linhardt, Robert J; Wang, Xin; Chen, Shi-Guo

2017-09-01

A fucosylated chondroitin sulfate (FCS-pg) with highly repeated structure from Pearsonothuria graeffei was subjected to a in vitro fermentation model to investigate its fermentability and effects on human gut microflora. High performance liquid chromatography (HPLC) measurement found FCS-pg can be fermented to short chain fatty acids (SCFAs) by gut microflora from partial human fecal samples. 16S rRNA gene-based polymerase chain reaction-based denaturing gradient gel electrophoresis (PCR-DGGE) profiling and real-time quantitative PCR analysis showed that FCS-pg mainly increased the proportions of Clostridium cluster XI, Bacteriodes prevotella group, Bifidobacterium genus, Clostridium cluster I and Clostridium cluster XIVab, whereas the numbers of the Enterobacteriaceae and Lactobacillus decreased. These results indicated that FCS-pg was mainly fermented by Bacteroides, Bifidobacterium and Clostridium. It increased the content of probiotics bacteria in achieving health-enhancing effect, was slightly different than most sulfated polysaccharides from marine animals. The current study provides useful new information on the mechanism of absorption and functional activity on FCS-pg within the gastrointestinal tract of the human body. Copyright © 2017. Published by Elsevier B.V.
Foam core shield (FCS) systems : a new dual - purpose technology for shielding against meteoroid strike damage and for thermal control of spacecrafts/satellite components

NASA Technical Reports Server (NTRS)

Adams, Marc A.; Zwissler, James G.; Hayes, Charles; Fabensky, Beth; Cornelison, Charles; Alexander, Lesley; Bishop, Karen

2005-01-01

A new technology is being developed that can protect spacecraft and satellite components against damage from meteoroid strikes and control the thermal environment of the protected components. This technology, called Foam Core Shield (FCS) systems, has the potential to replace the multi-layer insulation blankets (MLI) that have been used on spacecraft for decades. In order to be an attractive candidate for replacing MLI, FCS systems should not only provide superior protection against meteoroid strikes but also provide an equal or superior ability to control the temperature of the protected component. Properly designed FCS systems can provide these principal functions, meteoroid strike protection and thermal control, with lower system mass and a smaller system envelope than ML.
Combination of Follicular and Epidermal Cell Suspension as a Novel Surgical Approach in Difficult-to-Treat Vitiligo: A Randomized Clinical Trial.

PubMed

Razmi T, Muhammed; Kumar, Ravinder; Rani, Seema; Kumaran, Sendhil M; Tanwar, Sushma; Parsad, Davinder

2018-03-01

Epidermal cell suspension (ECS) and follicular cell suspension (FCS) are successful surgical modalities for the treatment of stable vitiligo. However, repigmentation in generalized and acrofacial vitiligo and over acral or bony sites (eg, elbows, knees, iliac crests, and malleoli), which are difficult to treat, is challenging. To study the efficacy of transplanting a combination of autologous, noncultured ECS and FCS (ECS + FCS) compared with ECS alone in stable vitiligo. A prospective, observer-blinded, active-controlled, randomized clinical trial was conducted at a tertiary care hospital, with treatment administered as an outpatient procedure. Thirty participants who had stable vitiligo with symmetrical lesions were recruited between October 18, 2013, and October 28, 2016. All of the lesions were resistant to medical modalities with minimum lesional stability of 1 year. Intent-to-treat analysis was used. ECS + FCS was prepared by mixing equal amounts (in cell number) of FCS with ECS. After manual dermabrasion, ECS was applied to 1 lesion and ECS + FCS was applied to the anatomically based paired lesion of the same patient. No adjuvant treatment was given. Patients were followed up at 4, 8, and 16 weeks by a blinded observer and extent of repigmentation, color match, pattern of repigmentation, patient satisfaction and complications were noted. Both the visual and the computerized image analysis methods were used for outcome assessment. Cell suspensions were assessed post hoc for OCT4+ stem cell counts using flow cytometry; expression of stem cell factor and basic fibroblast growth factor was evaluated using quantitative relative messenger RNA expression. Of the 30 patients included in the study, 18 (60%) were women; mean (SD) age was 23.4 (6.4) years. Seventy-four percent of the lesions (62 of 84) were difficult-to-treat vitiligo. ECS + FCS showed superior repigmentation outcomes compared with ECS: extent (76% vs 57%, P < .001), rapidity (48% vs 31%, P = .001), color match (73% vs 61%, P < .001), and patient satisfaction (mean [SD] patient global assessment score, 23.30 [6.89] vs 20.81 [6.61], P = .047). Melanocyte stem cell counts (2% in ECS + FCS vs 0.5% in ECS) as well as expression of basic fibroblast growth factor (11.8-fold) and stem cell factor (6.0-fold) were higher in ECS + FCS suspension (P<.05 for both). The findings from this study establish ECS + FCS as a novel approach in vitiligo surgery for attaining good to excellent repigmentation in a short period with good color match, even in difficult-to-treat vitiligo. ctri.nic.in Identifier: CTRI/2017/05/008692.
The Need for an Interdisciplinary Approach to Norm Diffusion: The Case of Fair and Equitable Benefit-sharing.

PubMed

Parks, Louisa; Morgera, Elisa

2015-11-01

No systematic study discusses the evolution of fair and equitable benefit-sharing across various areas of international law (environment, human rights, oceans), as well as at different levels of regulation (regional and national laws and guidelines, private law contracts, transboundary codes of conduct, customary laws of indigenous peoples and local communities). This article explores the usefulness of an interdisciplinary approach to the study of norm diffusion for understanding how and why fair and equitable benefit-sharing is articulated in different sites. The article discusses mechanisms, actors and frames in norm diffusion, drawing on literature from sociology, international relations and law. The article uncovers underlying similarities in scholarship on norm diffusion across the disciplines considered. It also reflects on the value of an interdisciplinary approach that encourages legal scholars to consider the implications of power structures in the diffusion of law, while the nuances of legal knowledge may lead other social scientists to revisit accepted findings on norm diffusion. These findings appear particularly useful for informing an assessment of the potential of fair and equitable benefit-sharing to promote the conservation and sustainable use of natural resources in a fair and equitable manner in the face of power asymmetries.
Mitigation of CO Poisoning on Functionalized Pt/TiN(001) Surface: A Fundamental Study of the Next-Generation Fuel Cell Technologies

DTIC Science & Technology

2014-05-27

TiN(100) surface (Pt/TiN) could be a promising catalyst for proton exchange membrane fuel cells ( PEM FCs). The adsorption properties of molecules on Pt...under both acidic and basic operation conditions in PEM FCs. 15. SUBJECT TERMS Catalysis, fuel cells , density functional theory, density functional...poisoning on functionalized Pt/TiN surfaces under both acidic and basic operation conditions in PEM FCs. 15. SUBJECT TERMS Catalysis, fuel cells
The diffusion dynamics of PEGylated liposomes in the intact vitreous of the ex vivo porcine eye: A fluorescence correlation spectroscopy and biodistribution study.

PubMed

Eriksen, Anne Z; Brewer, Jonathan; Andresen, Thomas L; Urquhart, Andrew J

2017-04-30

The diffusion dynamics of nanocarriers in the vitreous and the influence of nanocarrier physicochemical properties on these dynamics is an important aspect of the efficacy of intravitreal administered nanomedicines for the treatment of posterior segment eye diseases. Here we use fluorescence correlation spectroscopy (FCS) to determine liposome diffusion coefficients in the intact vitreous (D Vit ) of ex vivo porcine eyes using a modified Miyake-Apple technique to minimize the disruption of the vitreous fine structure. We chose to investigate whether the zeta potential of polyethylene glycol functionalized (i.e. PEGylated) liposomes altered liposome in situ diffusion dynamics in the vitreous. Non-PEGylated cationic nanocarriers have previously shown little to no diffusion in the vitreous, whilst neutral and anionic have shown diffusion. The liposomes investigated had diameters below 150nm and zeta potentials ranging from -20 to +12mV. We observed that PEGylated cationic liposomes had significantly lower D Vit values (1.14μm 2 s -1 ) than PEGylated neutral and anionic liposomes (2.78 and 2.87μm 2 s -1 ). However, PEGylated cationic liposomes had a similar biodistribution profile across the vitreous to the other systems. These results show that PEGylated cationic liposomes with limited cationic charge can diffuse across the vitreous and indicate that the vitreous as a barrier to nanocarriers (Ø<500nm) is more complicated than simply an electrostatic barrier as previously suggested. Copyright © 2017 Elsevier B.V. All rights reserved.
Macromolecular crowding gives rise to microviscosity, anomalous diffusion and accelerated actin polymerization

NASA Astrophysics Data System (ADS)

Rashid, Rafi; Chee, Stella Min Ling; Raghunath, Michael; Wohland, Thorsten

2015-05-01

Macromolecular crowding (MMC) has been used in various in vitro experimental systems to mimic in vivo physiology. This is because the crowded cytoplasm of cells contains many different types of solutes dissolved in an aqueous medium. MMC in the extracellular microenvironment is involved in maintaining stem cells in their undifferentiated state (niche) as well as in aiding their differentiation after they have travelled to new locations outside the niche. MMC at physiologically relevant fractional volume occupancies (FVOs) significantly enhances the adipogenic differentiation of human bone marrow-derived mesenchymal stem cells during chemically induced adipogenesis. The mechanism by which MMC produces this enhancement is not entirely known. In the context of extracellular collagen deposition, we have recently reported the importance of optimizing the FVO while minimizing the bulk viscosity. Two opposing properties will determine the net rate of a biochemical reaction: the negative effect of bulk viscosity and the positive effect of the excluded volume, the latter being expressed by the FVO. In this study we have looked more closely at the effect of viscosity on reaction rates. We have used fluorimetry to measure the rate of actin polymerization and fluorescence correlation spectroscopy (FCS) to measure diffusion of various probes in solutions containing the crowder Ficoll at physiological concentrations. Similar to its effect on collagen, Ficoll enhanced the actin polymerization rate despite increasing the bulk viscosity. Our FCS measurements reveal a relatively minor component of anomalous diffusion. In addition, our measurements do suggest that microviscosity becomes relevant in a crowded environment. We ruled out bulk viscosity as a cause of the rate enhancement by performing the actin polymerization assay in glycerol. These opposite effects of Ficoll and glycerol led us to conclude that microviscosity becomes relevant at the length scale of the reacting molecules within a crowded microenvironment. The excluded volume effect (arising from crowding) increases the effective concentration of actin, which increases the reaction rate, while the microviscosity does not increase sufficiently to lower the reaction rate. This study reveals finer details about the mechanism of MMC.
Macromolecular crowding gives rise to microviscosity, anomalous diffusion and accelerated actin polymerization.

PubMed

Rashid, Rafi; Chee, Stella Min Ling; Raghunath, Michael; Wohland, Thorsten

2015-04-30

Macromolecular crowding (MMC) has been used in various in vitro experimental systems to mimic in vivo physiology. This is because the crowded cytoplasm of cells contains many different types of solutes dissolved in an aqueous medium. MMC in the extracellular microenvironment is involved in maintaining stem cells in their undifferentiated state (niche) as well as in aiding their differentiation after they have travelled to new locations outside the niche. MMC at physiologically relevant fractional volume occupancies (FVOs) significantly enhances the adipogenic differentiation of human bone marrow-derived mesenchymal stem cells during chemically induced adipogenesis. The mechanism by which MMC produces this enhancement is not entirely known. In the context of extracellular collagen deposition, we have recently reported the importance of optimizing the FVO while minimizing the bulk viscosity. Two opposing properties will determine the net rate of a biochemical reaction: the negative effect of bulk viscosity and the positive effect of the excluded volume, the latter being expressed by the FVO. In this study we have looked more closely at the effect of viscosity on reaction rates. We have used fluorimetry to measure the rate of actin polymerization and fluorescence correlation spectroscopy (FCS) to measure diffusion of various probes in solutions containing the crowder Ficoll at physiological concentrations. Similar to its effect on collagen, Ficoll enhanced the actin polymerization rate despite increasing the bulk viscosity. Our FCS measurements reveal a relatively minor component of anomalous diffusion. In addition, our measurements do suggest that microviscosity becomes relevant in a crowded environment. We ruled out bulk viscosity as a cause of the rate enhancement by performing the actin polymerization assay in glycerol. These opposite effects of Ficoll and glycerol led us to conclude that microviscosity becomes relevant at the length scale of the reacting molecules within a crowded microenvironment. The excluded volume effect (arising from crowding) increases the effective concentration of actin, which increases the reaction rate, while the microviscosity does not increase sufficiently to lower the reaction rate. This study reveals finer details about the mechanism of MMC.
Bivalirudin and clopidogrel with and without eptifibatide for elective stenting: effects on platelet function, thrombelastographic indexes, and their relation to periprocedural infarction results of the CLEAR PLATELETS-2 (Clopidogrel with Eptifibatide to Arrest the Reactivity of Platelets) study.

PubMed

Gurbel, Paul A; Bliden, Kevin P; Saucedo, Jorge F; Suarez, Thomas A; DiChiara, Joseph; Antonino, Mark J; Mahla, Elisabeth; Singla, Anand; Herzog, William R; Bassi, Ashwani K; Hennebry, Thomas A; Gesheff, Tania B; Tantry, Udaya S

2009-02-24

The primary objective of this study was to compare the effect of therapy with bivalirudin alone versus bivalirudin plus eptifibatide on platelet reactivity measured by turbidometric aggregometry and thrombin-induced platelet-fibrin clot strength (TIP-FCS) measured by thrombelastography in percutaneous coronary intervention (PCI) patients. The secondary aim was to study the relation of platelet aggregation and TIP-FCS to the occurrence of periprocedural infarction. Bivalirudin is commonly administered alone to clopidogrel naïve (CN) patients and to patients on maintenance clopidogrel therapy (MT) undergoing elective stenting. The effect of adding eptifibatide to bivalirudin on platelet reactivity (PR) and TIP-FCS, and their relation to periprocedural infarction in these patients are unknown. Patients (n = 200) stratified to clopidogrel treatment status were randomly treated with bivalirudin (n = 102) or bivalirudin plus eptifibatide (n = 98). One hundred twenty-eight CN patients were loaded with 600 mg clopidogrel immediately after stenting, and 72 MT patients were not loaded. The PR, TIP-FCS, and myonecrosis markers were serially determined. In CN and MT patients, bivalirudin plus eptifibatide was associated with markedly lower PR at all times (5- and 20-microM adenosine diphosphate-induced, and 15- and 25-microM thrombin receptor activator peptide-induced aggregation; p < 0.001 for all) and reduced mean TIP-FCS (p < 0.05). Patients who had a periprocedural infarction had higher mean 18-h PR (p < 0.0001) and TIP-FCS (p = 0.002). For elective stenting, the addition of eptifibatide to bivalirudin lowered PR to multiple agonists and the tensile strength of the TIP-FCS, 2 measurements strongly associated with periprocedural myonecrosis. Future studies of PR and TIP-FCS for elective stenting may facilitate personalized antiplatelet therapy and enhance the selection of patients for glycoprotein IIb/IIIa blockade. (Peri-Procedural Myocardial Infarction, Platelet Reactivity, Thrombin Generation, and Clot Strength: Differential Effects of Eptifibatide + Bivalirudin Versus Bivalirudin [CLEAR PLATELETS-2]; NCT00370045.
A non-local structural derivative model for characterization of ultraslow diffusion in dense colloids

NASA Astrophysics Data System (ADS)

Liang, Yingjie; Chen, Wen

2018-03-01

Ultraslow diffusion has been observed in numerous complicated systems. Its mean squared displacement (MSD) is not a power law function of time, but instead a logarithmic function, and in some cases grows even more slowly than the logarithmic rate. The distributed-order fractional diffusion equation model simply does not work for the general ultraslow diffusion. Recent study has used the local structural derivative to describe ultraslow diffusion dynamics by using the inverse Mittag-Leffler function as the structural function, in which the MSD is a function of inverse Mittag-Leffler function. In this study, a new stretched logarithmic diffusion law and its underlying non-local structural derivative diffusion model are proposed to characterize the ultraslow diffusion in aging dense colloidal glass at both the short and long waiting times. It is observed that the aging dynamics of dense colloids is a class of the stretched logarithmic ultraslow diffusion processes. Compared with the power, the logarithmic, and the inverse Mittag-Leffler diffusion laws, the stretched logarithmic diffusion law has better precision in fitting the MSD of the colloidal particles at high densities. The corresponding non-local structural derivative diffusion equation manifests clear physical mechanism, and its structural function is equivalent to the first-order derivative of the MSD.
Corneal grafting for the treatment of feline corneal sequestrum: a retrospective study of 18 eyes (13 cats).

PubMed

Laguna, Fernando; Leiva, Marta; Costa, Daniel; Lacerda, Rodrigo; Peña Gimenez, Teresa

2015-07-01

To determine the clinical outcome of corneal grafting for the treatment of feline corneal sequestrum (FCS). Domestic cats. A review of the medical records of cats that underwent keratoplasty as a treatment of FCS at the VTH-UAB, from 2002 to 2012, was carried out. Thirteen cats (18 eyes) of different breed, age, and gender were included. Persian cats were overrepresented (12/13;92%). There were nine males and four females, of a mean age of 3.4 years (0.7-7.1). Ipsilateral chronic corneal ulceration was reported as the most common concurrent ocular disease (6/18;33%). Keratoplasty was performed bilaterally in 5 cats (5/13;38%) and unilaterally in 8 (8/13;62%). Lamellar keratoplasty was performed in 17 eyes (17/18;95%) and full-thickness keratoplasty in 1 (1/18;5%). Mean graft size was 8.3 mm (4-11.5). Fresh homologous graft was performed in 2 eyes (2/18;11%) and frozen graft in 16 (16/18;89%). Of the latter group, homologous graft was performed in 6 eyes (6/16;37.5%) and heterologous in 10 (10/16;62.5%). In all the cats, postoperative treatment included topical antibiotics, corticosteroids, cycloplegics, and 0.2% cyclosporine A. Median follow-up time was 18.2 months, and main postoperative complications were diffuse mild epithelial pigment formation (2/18;11%), graft malacia (1/18;5%), and sequestrum recurrence (1/18;5%). Mean epithelial healing time was 19.2 days. Good visual outcome was achieved in all the eyes (100%), the majority of them having faint or mild corneal opacity (15/18;83%). Keratoplasty is an effective surgical treatment for FCS. The donor tissue provides excellent tectonic support to the affected corneas, with good visual and cosmetic outcome. © 2014 American College of Veterinary Ophthalmologists.
The implementation of mindfulness-based interventions and educational interventions to support family caregivers of patients with cancer: A systematic review.

PubMed

Al Daken, Laila I; Ahmad, Muayyad M

2018-05-10

This review aims to determine the effectiveness of mindfulness-based interventions (MBIs) and educational interventions (EIs) as supportive care for family caregivers (FCs) of patients with cancer. Review was conducted following PRISMA guidelines. The search protocol was performed using EBSCO, Google Scholar, and Science Direct for the studies published between 2007 and 2017. Little evidence is available on the usefulness of MBIs among FCs of patients with cancer. However, the available evidence supports that MBIs have the potential to enhance overall well-being and reduce the burden for FCs. EIs have shown positive outcomes on some aspects of well-being and reducing the burden. The findings provide preliminary support for effectiveness of MBIs and EIs as a supportive care for FCs. © 2018 Wiley Periodicals, Inc.
Best kept secrets ... First Coast Systems, Inc. (FCS).

PubMed

Andrew, W F

1991-04-01

The FCS/APaCS system is a viable option for small-to medium-size hospitals (up to 400 beds). The table-driven system takes full advantage of IBM AS/400 computer architecture. A comprehensive application set, provided in an integrated database environment, is adaptable to multi-facility environments. Price/performance appears to be competitive. Commitment to IBM AS/400 environment assures cost-effective hardware platforms backed by IBM support and resources. As an IBM Health Industry Business Partner, FCS (and its clients) benefits from IBM's well-known commitment to quality and service. Corporate emphasis on user involvement and satisfaction, along with a commitment to quality and service for the APaCS systems, assures clients of "leading edge" capabilities in this evolutionary healthcare delivery environment. FCS/APaCS will be a strong contender in selected marketing environments.
A quality function deployment framework for the service quality of health information websites.

PubMed

Chang, Hyejung; Kim, Dohoon

2010-03-01

This research was conducted to identify both the users' service requirements on health information websites (HIWs) and the key functional elements for running HIWs. With the quality function deployment framework, the derived service attributes (SAs) are mapped into the suppliers' functional characteristics (FCs) to derive the most critical FCs for the users' satisfaction. Using the survey data from 228 respondents, the SAs, FCs and their relationships were analyzed using various multivariate statistical methods such as principal component factor analysis, discriminant analysis, correlation analysis, etc. Simple and compound FC priorities were derived by matrix calculation. Nine factors of SAs and five key features of FCs were identified, and these served as the basis for the house of quality model. Based on the compound FC priorities, the functional elements pertaining to security and privacy, and usage support should receive top priority in the course of enhancing HIWs. The quality function deployment framework can improve the FCs of the HIWs in an effective, structured manner, and it can also be utilized for critical success factors together with their strategic implications for enhancing the service quality of HIWs. Therefore, website managers could efficiently improve website operations by considering this study's results.
The Need for an Interdisciplinary Approach to Norm Diffusion: The Case of Fair and Equitable Benefit‐sharing

PubMed Central

Morgera, Elisa

2015-01-01

No systematic study discusses the evolution of fair and equitable benefit‐sharing across various areas of international law (environment, human rights, oceans), as well as at different levels of regulation (regional and national laws and guidelines, private law contracts, transboundary codes of conduct, customary laws of indigenous peoples and local communities). This article explores the usefulness of an interdisciplinary approach to the study of norm diffusion for understanding how and why fair and equitable benefit‐sharing is articulated in different sites. The article discusses mechanisms, actors and frames in norm diffusion, drawing on literature from sociology, international relations and law. The article uncovers underlying similarities in scholarship on norm diffusion across the disciplines considered. It also reflects on the value of an interdisciplinary approach that encourages legal scholars to consider the implications of power structures in the diffusion of law, while the nuances of legal knowledge may lead other social scientists to revisit accepted findings on norm diffusion. These findings appear particularly useful for informing an assessment of the potential of fair and equitable benefit‐sharing to promote the conservation and sustainable use of natural resources in a fair and equitable manner in the face of power asymmetries. PMID:28018594

Gestational Exposure as Epigenetic Modifier of Breast Cancer Risk

DTIC Science & Technology

2016-10-01

were cultured for 72 h in control phenol red-free media (DMEM for MCF-7; RPMI for UACC-31299) supplemented with 10 % charcoal-stripped FCS in the...phenol red-free media RPMI supplemented with 10 % charcoal-stripped FCS in the presence or absence of 10 nM E2, alone or in combination with 2 μM αNF. A...in control phenol red-free media RPMI supplemented with 10 % charcoal- stripped FCS in the presence or absence of 10 nM E2, alone or in
Design, Development, and Demonstration of a Prognostic and Diagnostics Health Monitoring System for the CROWS Platform

DTIC Science & Technology

2010-06-01

automatically appended onto the data packet by the CC2420 transceiver. The frame control field (FCF), data sequence number, and frame check sequence (FCS...by the CC2420 over the MAC protocol data unit (MPDU), i.e., the length field is not part of the FCS. This field is automatically generated and...verified by the CC2420 hardware when the AUTOCRC control bit is set in the MODEMCTRL0 control register’s field . If the FCS check indicates that a data
Reduction of CO2 to low carbon alcohols on CuO FCs/Fe2O3 NTs catalyst with photoelectric dual catalytic interfaces

NASA Astrophysics Data System (ADS)

Li, Peiqiang; Wang, Huying; Xu, Jinfeng; Jing, Hua; Zhang, Jun; Han, Haixiang; Lu, Fusui

2013-11-01

In this paper, the CuO FCs/Fe2O3 NTs catalyst was obtained after Fe2O3 nanotubes (Fe2O3 NTs) were decorated with CuO flower clusters (CuO FCs) by the pulse electrochemical deposition method. The in situ vertically aligned Fe2O3 NTs were prepared on the ferrous substrate by a potentiostatic anodization method. The SEM result showed the volcano-like Fe2O3 NTs were arranged in order and the CuO FCs constituted of flaky CuO distributed on the Fe2O3 NTs surface uniformly. After CuO FCs were loaded on Fe2O3 NTs, the absorption of visible light was enhanced noticeably, and its band gap narrowed to 1.78 eV from 2.03 eV. The conduction band and valence band locating at -0.73 eV and 1.05 eV, respectively were further obtained. In the PEC reduction of CO2 process, methanol and ethanol were two major products identified by chromatography. Their contents reached 1.00 mmol L-1 cm-2 and 107.38 μmol L-1 cm-2 after 6 h, respectively. This high-efficiency catalyst with photoelectric dual catalytic interfaces has a great guidance and reference significance for CO2 reduction to liquid carbon fuels.In this paper, the CuO FCs/Fe2O3 NTs catalyst was obtained after Fe2O3 nanotubes (Fe2O3 NTs) were decorated with CuO flower clusters (CuO FCs) by the pulse electrochemical deposition method. The in situ vertically aligned Fe2O3 NTs were prepared on the ferrous substrate by a potentiostatic anodization method. The SEM result showed the volcano-like Fe2O3 NTs were arranged in order and the CuO FCs constituted of flaky CuO distributed on the Fe2O3 NTs surface uniformly. After CuO FCs were loaded on Fe2O3 NTs, the absorption of visible light was enhanced noticeably, and its band gap narrowed to 1.78 eV from 2.03 eV. The conduction band and valence band locating at -0.73 eV and 1.05 eV, respectively were further obtained. In the PEC reduction of CO2 process, methanol and ethanol were two major products identified by chromatography. Their contents reached 1.00 mmol L-1 cm-2 and 107.38 μmol L-1 cm-2 after 6 h, respectively. This high-efficiency catalyst with photoelectric dual catalytic interfaces has a great guidance and reference significance for CO2 reduction to liquid carbon fuels. Electronic supplementary information (ESI) available: Reduction of CO2 to low carbon alcohols on CuO FCs/Fe2O3 NTs catalyst with photoelectric dual catalytic interfaces. See DOI: 10.1039/c3nr03352j
Altered gravity influences rDNA and NopA100 localization in nucleoli

NASA Astrophysics Data System (ADS)

Sobol, M. A.; Kordyum, E. L.

Fundamental discovery of gravisensitivity of cells no specified to gravity perception focused increasing attention on an elucidation of the mechanisms involved in altered gravity effects at the cellular and subcellular levels. The nucleolus is the transcription site of rRNA genes as well as the site of processing and initial packaging of their transcripts with ribosomal and nonribosomal proteins. The mechanisms inducing the changes in the subcomponents of the nucleolus that is morphologically defined yet highly dynamic structure are still unknown in detail. To understand the functional organization of the nucleolus as in the control as under altered gravity conditions it is essential to determine both the precise location of rDNA and the proteins playing the key role in rRNA processing. Lepidium sativum seeds were germinated in 1% agar medium on the slow horizontal clinostat (2 rpm) and in the stationary conditions. We investigated the root meristematic cells dissected from the seedlings grown in darkness for two days. The investigations were carried out with anti-DNA and anti-NopA100 antibodies labeling as well as with TdT procedure, and immunogold electron microscopy. In the stationary growth conditions, the anti-DNA antibody as well TdT procedure were capable of detecting fibrillar centers (FCs) and the dense fibrillar component (DFC) in the nucleolus. In FCs, gold particles were revealed on the condensed chromatin inclusions, internal fibrils of decondensed rDNA and the transition zone FC-DFC. Quantitatively, FCs appeared 1,5 times more densely labeled than DFC. NopA100 was localized in FCs and in DFC. In FCs, the most of protein was revealed in the transition zone FC-DFC. After a quantitative study, FCs and the transition zone FC-DFC appeared to contain NopA100 1,7 times more than DFC. Under the conditions of altered gravity, quantitative data clearly showed a redistribution of nucleolar DNA and NopA100 between FCs and DFC in comparison with the control. In labeling both with anti-DNA antibody and by TdT method, 1,5 times more gold particles were localized on FCs, and 1,5 times less in DFC. Unlike the control, condensed r-chromatin blocks and inner rDNA were labeled much more than the transition zone FC-DFC in fibrillar centers. The content of NopA100 in FCs and the transition zone FC-DFC was 2,4 times more than in the control. Twice less quantity of the protein was revealed in DFC as compared to the control. In fibrillar centers, the majority of NopA100 was localized in the inner space of FCs than in the transition zone FC-DFC. Re-localization of rDNA and NopA100 in the nucleolar subcomponents indicates lowering the level of rDNA transcription as well as middle and late processing of rRNA that let us to propose lowering the functional activity of the nucleolus under the influence of altered gravity.
Diffusion behavior of the fluorescent proteins eGFP and Dreiklang in solvents of different viscosity monitored by fluorescence correlation spectroscopy

NASA Astrophysics Data System (ADS)

Junghans, Cornelia; Schmitt, Franz-Josef; Vukojević, Vladana; Friedrich, Thomas

2016-12-01

Fluorescence correlation spectroscopy relies on temporal autocorrelation analysis of fluorescence intensity fluctuations that spontaneously arise in systems at equilibrium due to molecular motion and changes of state that cause changes in fluorescence, such as triplet state transition, photoisomerization and other photophysical transformations, to determine the rates of these processes. The stability of a fluorescent molecule against dark state conversion is of particular concern for chromophores intended to be used as reference tags for comparing diffusion processes on multiple time scales. In this work, we analyzed properties of two fluorescent proteins, the photoswitchable Dreiklang and its parental eGFP, in solvents of different viscosity to vary the diffusion time through the observation volume element by several orders of magnitude. In contrast to eGFP, Dreiklang undergoes a dark-state conversion on the time scale of tens to hundreds of microseconds under conditions of intense fluorescence excitation, which results in artificially shortened diffusion times if the diffusional motion through the observation volume is sufficiently slowed down. Such photophysical quenching processes have also been observed in FCS studies on other photoswitchable fluorescent proteins including Citrine, from which Dreiklang was derived by genetic engineering. This property readily explains the discrepancies observed previously between the diffusion times of eGFP- and Dreiklang-labeled plasma membrane protein complexes.
Development of a Model Following Control Law for Inflight Simulation and Flight Controls Research

NASA Technical Reports Server (NTRS)

Takahashi, Mark; Fletcher, Jay; Aiken, Edwin W. (Technical Monitor)

1994-01-01

The U.S. Army and NASA are currently developing the Rotorcraft Aircrew Systems Concepts Airborne Laboratory (RASCAL) at the Ames Research Center. RASCAL, shown in Figure 1, is a UH-60, which is being modified in a phased development program to have a research fly-by-wire flight control system, and an advanced navigation research platform. An important part of the flight controls and handling qualities research on RASCAL will be an FCS design for the aircraft to achieve high bandwidth control responses and disturbance rejection characteristics. Initially, body states will be used as feedbacks, but research into the use of rotor states will also be considered in later stages to maximize agility and maneuverability. In addition to supporting flight controls research, this FCS design will serve as the inflight simulation control law to support basic handling qualities, guidance, and displays research. Research in high bandwidth controls laws is motivated by the desire to improve the handling qualities in aggressive maneuvering and in severely degraded weather conditions. Naturally, these advantages will also improve the quality of the model following, thereby improving the inflight simulation capabilities of the research vehicle. High bandwidth in the control laws provides tighter tracking allowing for higher response bandwidths which can meet handling qualities requirements for aggressive maneuvering. System sensitivity is also reduced preventing variations in the response from the vehicle due to changing flight conditions. In addition, improved gust rejection will result from this reduced sensitivity. The gust rejection coupled with a highly stable system will make more precise maneuvering and pointing possible in severely degraded weather conditions. The difficulty in achieving higher bandwidths from the control laws in the feedback and in the responses arises from the complexity of the models that are needed to produce a satisfactory design. In this case, high quality models that include rotor dynamics in a physically meaningful context must be available. A non-physical accounting of the rotor, such as lumping the effect as a time delay, is not likely to produce the desired results. High order simulation models based on first principals are satisfactory for the initial design phase in order to work out the control law design concept and get an initial set of gains. These models, however, have known deficiencies, which must be resolved in the final control law design. The error in the pitch-roll cross coupling is one notable deficiency that even sophisticated rotorcraft models including complex wake aerodynamics have yet to capture successfully. This error must be accounted for to achieve the desired decoupling. The approach to design the proposed inflight simulation control law is based on using a combination of simulation and identified models. The linear and nonlinear higher order models were used to develop an explicit model following control structure. This structure was developed to accommodate the design of control laws compliant to many of the quantitative requirements in ADS-33C. Furthermore, it also allows for control law research using rotor-state feedback and other design methodologies such as Quantitative Feedback and H-Infinity. Final gain selection will be based on higher order identified models which include rotor degrees of freedom.
Characterization of two Streptomyces enzymes that convert ferulic acid to vanillin.

PubMed

Yang, Wenwen; Tang, Hongzhi; Ni, Jun; Wu, Qiulin; Hua, Dongliang; Tao, Fei; Xu, Ping

2013-01-01

Production of flavors from natural substrates by microbial transformation has become a growing and expanding field of study over the past decades. Vanillin, a major component of vanilla flavor, is a principal flavoring compound used worldwide. Streptomyces sp. strain V-1 is known to be one of the most promising microbial producers of natural vanillin from ferulic acid. Although identification of the microbial genes involved in the biotransformation of ferulic acid to vanillin has been previously reported, purification and detailed characterization of the corresponding enzymes with important functions have rarely been studied. In this study, we isolated and identified 2 critical genes, fcs and ech, encoding feruloyl-CoA synthetase and enoyl-CoA hydratase/aldolase, respectively, which are involved in the vanillin production from ferulic acid. Both genes were heterologously expressed in Escherichia coli, and the resting cell reactions for converting ferulic acid to vanillin were performed. The corresponding crucial enzymes, Fcs and Ech, were purified for the first time and the enzymatic activity of each purified protein was studied. Furthermore, Fcs was comprehensively characterized, at an optimal pH of 7.0 and temperature of 30°C. Kinetic constants for Fcs revealed the apparent Km, kcat, and Vmax values to be 0.35 mM, 67.7 s(-1), and 78.2 U mg(-1), respectively. The catalytic efficiency (kcat/Km) value of Fcs was 193.4 mM(-1) s(-1) for ferulic acid. The characterization of Fcs and Ech may be helpful for further research in the field of enzymatic engineering and metabolic regulation.
A characteristic chondroitin sulfate trisaccharide unit with a sulfated fucose branch exhibits neurite outgrowth-promoting activity: Novel biological roles of fucosylated chondroitin sulfates isolated from the sea cucumber Apostichopus japonicus.

PubMed

Shida, Miharu; Mikami, Tadahisa; Tamura, Jun-Ichi; Kitagawa, Hiroshi

2017-06-03

Chondroitin sulfate (CS) is a class of sulfated glycosaminoglycan (GAG) chains that consist of repeating disaccharide unit composed of glucuronic acid (GlcA) and N-acetylgalactosamine (GalNAc). CS chains are found throughout the pericellular and extracellular spaces and contribute to the formation of functional microenvironments for numerous biological events. However, their structure-function relations remain to be fully characterized. Here, a fucosylated CS (FCS) was isolated from the body wall of the sea cucumber Apostichopus japonicus. Its promotional effects on neurite outgrowth were assessed by using isolated polysaccharides and the chemically synthesized FCS trisaccharide β-D-GalNAc(4,6-O-disulfate) (1-4)[α-l-fucose (2,4-O-disulfate) (1-3)]-β-D-GlcA. FCS polysaccharides contained the E-type disaccharide unit GlcA-GalNAc(4,6-O-disulfate) as a CS major backbone structure and carried distinct sulfated fucose branches. Despite their relatively lower abundance of E unit, FCS polysaccharides exhibited neurite outgrowth-promoting activity comparable to squid cartilage-derived CS-E polysaccharides, which are characterized by their predominant E units, suggesting potential roles of the fucose branch in neurite outgrowth. Indeed, the chemically synthesized FCS trisaccharide was as effective as CS-E tetrasaccharide in stimulating neurite elongation in vitro. In conclusion, FCS trisaccharide units with 2,4-O-disulfated fucose branches may provide new insights into understanding the structure-function relations of CS chains. Copyright © 2017 Elsevier Inc. All rights reserved.
Characterization of Two Streptomyces Enzymes That Convert Ferulic Acid to Vanillin

PubMed Central

Yang, Wenwen; Tang, Hongzhi; Ni, Jun; Wu, Qiulin; Hua, Dongliang; Tao, Fei; Xu, Ping

2013-01-01

Production of flavors from natural substrates by microbial transformation has become a growing and expanding field of study over the past decades. Vanillin, a major component of vanilla flavor, is a principal flavoring compound used worldwide. Streptomyces sp. strain V-1 is known to be one of the most promising microbial producers of natural vanillin from ferulic acid. Although identification of the microbial genes involved in the biotransformation of ferulic acid to vanillin has been previously reported, purification and detailed characterization of the corresponding enzymes with important functions have rarely been studied. In this study, we isolated and identified 2 critical genes, fcs and ech, encoding feruloyl-CoA synthetase and enoyl-CoA hydratase/aldolase, respectively, which are involved in the vanillin production from ferulic acid. Both genes were heterologously expressed in Escherichia coli, and the resting cell reactions for converting ferulic acid to vanillin were performed. The corresponding crucial enzymes, Fcs and Ech, were purified for the first time and the enzymatic activity of each purified protein was studied. Furthermore, Fcs was comprehensively characterized, at an optimal pH of 7.0 and temperature of 30°C. Kinetic constants for Fcs revealed the apparent K m, k cat, and V max values to be 0.35 mM, 67.7 s−1, and 78.2 U mg−1, respectively. The catalytic efficiency (k cat/K m) value of Fcs was 193.4 mM−1 s−1 for ferulic acid. The characterization of Fcs and Ech may be helpful for further research in the field of enzymatic engineering and metabolic regulation. PMID:23840666
X-38 Experimental Controls Laws

NASA Technical Reports Server (NTRS)

Munday, Steve; Estes, Jay; Bordano, Aldo J.

2000-01-01

X-38 Experimental Control Laws X-38 is a NASA JSC/DFRC experimental flight test program developing a series of prototypes for an International Space Station (ISS) Crew Return Vehicle, often called an ISS "lifeboat." X- 38 Vehicle 132 Free Flight 3, currently scheduled for the end of this month, will be the first flight test of a modem FCS architecture called Multi-Application Control-Honeywell (MACH), originally developed by the Honeywell Technology Center. MACH wraps classical P&I outer attitude loops around a modem dynamic inversion attitude rate loop. The dynamic inversion process requires that the flight computer have an onboard aircraft model of expected vehicle dynamics based upon the aerodynamic database. Dynamic inversion is computationally intensive, so some timing modifications were made to implement MACH on the slower flight computers of the subsonic test vehicles. In addition to linear stability margin analyses and high fidelity 6-DOF simulation, hardware-in-the-loop testing is used to verify the implementation of MACH and its robustness to aerodynamic and environmental uncertainties and disturbances.
Quantitative confocal fluorescence microscopy of dynamic processes by multifocal fluorescence correlation spectroscopy

NASA Astrophysics Data System (ADS)

Krmpot, Aleksandar J.; Nikolić, Stanko N.; Vitali, Marco; Papadopoulos, Dimitrios K.; Oasa, Sho; Thyberg, Per; Tisa, Simone; Kinjo, Masataka; Nilsson, Lennart; Gehring, Walter J.; Terenius, Lars; Rigler, Rudolf; Vukojevic, Vladana

2015-07-01

Quantitative confocal fluorescence microscopy imaging without scanning is developed for the study of fast dynamical processes. The method relies on the use of massively parallel Fluorescence Correlation Spectroscopy (mpFCS). Simultaneous excitation of fluorescent molecules across the specimen is achieved by passing a single laser beam through a Diffractive Optical Element (DOE) to generate a quadratic illumination matrix of 32×32 light sources. Fluorescence from 1024 illuminated spots is detected in a confocal arrangement by a matching matrix detector consisting of the same number of single-photon avalanche photodiodes (SPADs). Software was developed for data acquisition and fast autoand cross-correlation analysis by parallel signal processing using a Graphic Processing Unit (GPU). Instrumental performance was assessed using a conventional single-beam FCS instrument as a reference. Versatility of the approach for application in biomedical research was evaluated using ex vivo salivary glands from Drosophila third instar larvae expressing a fluorescently-tagged transcription factor Sex Combs Reduced (Scr) and live PC12 cells stably expressing the fluorescently tagged mu-opioid receptor (MOPeGFP). We show that quantitative mapping of local concentration and mobility of transcription factor molecules across the specimen can be achieved using this approach, which paves the way for future quantitative characterization of dynamical reaction-diffusion landscapes across live cells/tissue with a submillisecond temporal resolution (presently 21 μs/frame) and single-molecule sensitivity.
Enzyme leaps fuel antichemotaxis

PubMed Central

Jee, Ah-Young; Dutta, Sandipan; Cho, Yoon-Kyoung

2018-01-01

There is mounting evidence that enzyme diffusivity is enhanced when the enzyme is catalytically active. Here, using superresolution microscopy [stimulated emission-depletion fluorescence correlation spectroscopy (STED-FCS)], we show that active enzymes migrate spontaneously in the direction of lower substrate concentration (“antichemotaxis”) by a process analogous to the run-and-tumble foraging strategy of swimming microorganisms and our theory quantifies the mechanism. The two enzymes studied, urease and acetylcholinesterase, display two families of transit times through subdiffraction-sized focus spots, a diffusive mode and a ballistic mode, and the latter transit time is close to the inverse rate of catalytic turnover. This biochemical information-processing algorithm may be useful to design synthetic self-propelled swimmers and nanoparticles relevant to active materials. Executed by molecules lacking the decision-making circuitry of microorganisms, antichemotaxis by this run-and-tumble process offers the biological function to homogenize product concentration, which could be significant in situations when the reactant concentration varies from spot to spot. PMID:29255047
Hollow-core FRP-concrete-steel bridge columns under extreme loading.

DOT National Transportation Integrated Search

2015-04-01

This report presents the behavior of hollow-core fiber reinforced polymer concrete - steel columns (HC-FCS) under : combined axial-flexural as well as vehicle collision loads. The HC-FCS column consists of a concrete wall sandwiched between an ou...
A Quality Function Deployment Framework for the Service Quality of Health Information Websites

PubMed Central

Kim, Dohoon

2010-01-01

Objectives This research was conducted to identify both the users' service requirements on health information websites (HIWs) and the key functional elements for running HIWs. With the quality function deployment framework, the derived service attributes (SAs) are mapped into the suppliers' functional characteristics (FCs) to derive the most critical FCs for the users' satisfaction. Methods Using the survey data from 228 respondents, the SAs, FCs and their relationships were analyzed using various multivariate statistical methods such as principal component factor analysis, discriminant analysis, correlation analysis, etc. Simple and compound FC priorities were derived by matrix calculation. Results Nine factors of SAs and five key features of FCs were identified, and these served as the basis for the house of quality model. Based on the compound FC priorities, the functional elements pertaining to security and privacy, and usage support should receive top priority in the course of enhancing HIWs. Conclusions The quality function deployment framework can improve the FCs of the HIWs in an effective, structured manner, and it can also be utilized for critical success factors together with their strategic implications for enhancing the service quality of HIWs. Therefore, website managers could efficiently improve website operations by considering this study's results. PMID:21818418
Autophagy in Drosophila ovaries is induced by starvation and is required for oogenesis.

PubMed

Barth, J M I; Szabad, J; Hafen, E; Köhler, K

2011-06-01

Autophagy, an evolutionarily conserved lysosome-mediated degradation, promotes cell survival under starvation and is controlled by insulin/target of rapamycin (TOR) signaling. In Drosophila, nutrient depletion induces autophagy in the fat body. Interestingly, nutrient availability and insulin/TOR signaling also influence the size and structure of Drosophila ovaries, however, the role of nutrient signaling and autophagy during this process remains to be elucidated. Here, we show that starvation induces autophagy in germline cells (GCs) and in follicle cells (FCs) in Drosophila ovaries. This process is mediated by the ATG machinery and involves the upregulation of Atg genes. We further demonstrate that insulin/TOR signaling controls autophagy in FCs and GCs. The analysis of chimeric females reveals that autophagy in FCs, but not in GCs, is required for egg development. Strikingly, when animals lack Atg gene function in both cell types, ovaries develop normally, suggesting that the incompatibility between autophagy-competent GCs and autophagy-deficient FCs leads to defective egg development. As egg morphogenesis depends on a tightly linked signaling between FCs and GCs, we propose a model in which autophagy is required for the communication between these two cell types. Our data establish an important function for autophagy during oogenesis and contributes to the understanding of the role of autophagy in animal development.
Quantification of the aggregation of magnetic nanoparticles with different polymeric coatings in cell culture medium

NASA Astrophysics Data System (ADS)

Eberbeck, D.; Kettering, M.; Bergemann, C.; Zirpel, P.; Hilger, I.; Trahms, L.

2010-10-01

The knowledge of the physico-chemical characteristics of magnetic nanoparticles (MNPs) is essential to enhance the efficacy of MNP-based therapeutic treatments (e.g. magnetic heating, magnetic drug targeting). According to the literature, the MNP uptake by cells may depend on the coating of MNPs, the surrounding medium as well as on the aggregation behaviour of the MNPs. Therefore, in this study, the aggregation behaviour of MNPs in various media was investigated. MNPs with different coatings were suspended in cell culture medium (CCM) containing fetal calf serum (FCS) and the distribution of the hydrodynamic sizes was measured by magnetorelaxometry (MRX). FCS as well as bovine serum albumin (BSA) buffer (phosphate buffered saline with 0.1% bovine serum albumin) may induce MNP aggregation. Its strength depends crucially on the type of coating. The degree of aggregation in CCM depends on its FCS content showing a clear, local maximum at FCS concentrations, where the IgG concentration (part of FCS) is of the order of the MNP number concentration. Thus, we attribute the observed aggregation behaviour to the mechanism of agglutination of MNPs by serum compartments as for example IgG. No aggregation was induced for MNPs coated with dextran, polyarabic acid or sodium phosphate, respectively, which were colloidally stable in CCM.
Convergent and divergent functional connectivity patterns in patients with long-term left-sided and right-sided deafness.

PubMed

Zhang, Yanyang; Mao, Zhiqi; Feng, Shiyu; Wang, Wenxin; Zhang, Jun; Yu, Xinguang

2018-02-05

Cortical reorganization may be induced in long-term single-sided deafness (SD); however, the influence of the deafness side on the functional changes remains poorly understood. Here, we investigated whole-brain functional connectivity patterns in long-term SD patients. The normalized voxel-based functional connectivity strength (FCS) was determined using resting-state fMRI (rs-fMRI) in 17 left-sided deafness (LD) patients, 21 right-sided deafness (RD) patients and 21 healthy controls (HCs). Relative to the HCs, both the LD and RD patients exhibited a reduction in the FCS in the ipsilateral visual cortex. However, compared to that in the HCs, a significantly higher FCS was observed in some regions in the salience and default-mode networks in the RD patients, but this FCS alternation pattern was not observed in the LD patients. A direct comparison of the two patient groups revealed a significantly increased FCS in the supplemental motor area in the LD group. Altogether, the long-term SD groups with LD and RD exhibited convergent and divergent functional connectivity patterns in whole-brain networks, providing promising evidence that the functional changes in long-term SD are highly deafness-side-dependent. Copyright © 2017 Elsevier B.V. All rights reserved.
Entropy-scaling laws for diffusion coefficients in liquid metals under high pressures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Qi-Long, E-mail: qlcao@mail.ustc.edu.cn; Shao, Ju-Xiang; Wang, Fan-Hou, E-mail: eatonch@gmail.com

2015-04-07

Molecular dynamic simulations on the liquid copper and tungsten are used to investigate the empirical entropy-scaling laws D{sup *}=A exp(BS{sub ex}), proposed independently by Rosenfeld and Dzugutov for diffusion coefficient, under high pressure conditions. We show that the scaling laws hold rather well for them under high pressure conditions. Furthermore, both the original diffusion coefficients and the reduced diffusion coefficients exhibit an Arrhenius relationship D{sub M}=D{sub M}{sup 0} exp(−E{sub M}/K{sub B}T), (M=un,R,D) and the activation energy E{sub M} increases with increasing pressure, the diffusion pre-exponential factors (D{sub R}{sup 0} and D{sub D}{sup 0}) are nearly independent of the pressure and element. Themore » pair correlation entropy, S{sub 2}, depends linearly on the reciprocal temperature S{sub 2}=−E{sub S}/T, and the activation energy, E{sub S}, increases with increasing pressure. In particular, the ratios of the activation energies (E{sub un}, E{sub R}, and E{sub D}) obtained from diffusion coefficients to the activation energy, E{sub S}, obtained from the entropy keep constants in the whole pressure range. Therefore, the entropy-scaling laws for the diffusion coefficients and the Arrhenius law are linked via the temperature dependence of entropy.« less
Human platelet lysate is a feasible candidate to replace fetal calf serum as medium supplement for blood vascular and lymphatic endothelial cells.

PubMed

Hofbauer, Pablo; Riedl, Sabrina; Witzeneder, Karin; Hildner, Florian; Wolbank, Susanne; Groeger, Marion; Gabriel, Christian; Redl, Heinz; Holnthoner, Wolfgang

2014-09-01

As angiogenic and lymphangiogenic key players, endothelial cells (ECs) are promising candidates for vascular regenerative therapies. To culture ECs in vitro, fetal calf serum (FCS) is most often used. However, some critical aspects of FCS usage, such as possible internalization of xenogeneic proteins and prions, must be considered. Therefore, the aim of this project was to determine if human platelet lysate (hPL) is a suitable alternative to FCS as medium supplement for the culture of blood vascular and lymphatic endothelial cells. The usability of hPL was tested by analysis of endothelial surface marker expression, metabolic activity and vasculogenic potential of outgrowth ECs (OECs), human umbilical vein ECs (HUVECs), and lymphatic ECs (LECs). Expression of EC markers CD31, VEGFR2, VE-cadherin and CD146 did not differ significantly between the EC types cultured in FCS or hPL. In addition, OECs, HUVECs and LECs formed tube-like structures on Matrigel when cultured in hPL and FCS. With the use of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromid assays, we found that the metabolic activity of OECs and LECs was slightly decreased when hPL was used. However, HUVECs and LECs did not show a significant decrease in metabolic activity, and HUVECs showed a slightly higher activity at low seeding densities. The use of hPL on different EC types did not reveal any substantial negative effects on EC behavior. Thus, hPL appears to be a favorable candidate to replace FCS as a medium supplement in the culture of ECs. Copyright © 2014 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.
Human platelet lysate successfully promotes proliferation and subsequent chondrogenic differentiation of adipose-derived stem cells: a comparison with articular chondrocytes.

PubMed

Hildner, F; Eder, M J; Hofer, K; Aberl, J; Redl, H; van Griensven, M; Gabriel, C; Peterbauer-Scherb, A

2015-07-01

Fetal calf serum (FCS) bears a potential risk for carrying diseases and eliciting immune reactions. Nevertheless, it still represents the gold standard as medium supplement in cell culture. In the present study, human platelet lysate (PL) was tested as an alternative to FCS for the expansion and subsequent chondrogenic differentiation of human adipose-derived stem cells (ASCs). ASCs were expanded with 10% FCS (group F) or 5% PL (group P). Subsequently, three-dimensional (3D) micromass pellets were created and cultured for 5 weeks in chondrogenic differentiation medium. Additionally, the de- and redifferentiation potential of human articular chondrocytes (HACs) was evaluated and compared to ASCs. Both HACs and ASCs cultured with PL showed strongly enhanced proliferation rates. Redifferentiation of HACs was possible for cells expanded up to 3.3 population doublings (PD). At this stage, PL-expanded HACs demonstrated better redifferentiation potential than FCS-expanded cells. ASCs could also be differentiated following extended passaging. Glycosaminoglycan (GAG) quantification and qRT-PCR of 10 cartilage related markers demonstrated a tendency for increased chondrogenic differentiation of PL-expanded ASCs compared to cells expanded with FCS. Histologically, collagen type II but also collagen type X was mainly present in group P. The present study demonstrates that PL strongly induces proliferation of ASCs, while the chondrogenic differentiation potential is retained. HACs also showed enhanced proliferation and even better redifferentiation when previously expanded with PL. This suggests that PL is superior to FCS as a supplement for the expansion of ASCs and HACs, particularly with regard to chondrogenic (re)differentiation. Copyright © 2013 John Wiley & Sons, Ltd.

Correction of self-reported BMI based on objective measurements: a Belgian experience.

PubMed

Drieskens, S; Demarest, S; Bel, S; De Ridder, K; Tafforeau, J

2018-01-01

Based on successive Health Interview Surveys (HIS), it has been demonstrated that also in Belgium obesity, measured by means of a self-reported body mass index (BMI in kg/m 2 ), is a growing public health problem that needs to be monitored as accurately as possible. Studies have shown that a self-reported BMI can be biased. Consequently, if the aim is to rely on a self-reported BMI, adjustment is recommended. Data on measured and self-reported BMI, derived from the Belgian Food Consumption Survey (FCS) 2014 offers the opportunity to do so. The HIS and FCS are cross-sectional surveys based on representative population samples. This study focused on adults aged 18-64 years (sample HIS = 6545 and FCS = 1213). Measured and self-reported BMI collected in FCS were used to assess possible misreporting. Using FCS data, correction factors (measured BMI/self-reported BMI) were calculated in function of a combination of background variables (region, gender, educational level and age group). Individual self-reported BMI of the HIS 2013 were then multiplied with the corresponding correction factors to produce a corrected BMI-classification. When compared with the measured BMI, the self-reported BMI in the FCS was underestimated (mean 0.97 kg/m 2 ). 28% of the obese people underestimated their BMI. After applying the correction factors, the prevalence of obesity based on HIS data significantly increased (from 13% based on the original HIS data to 17% based on the corrected HIS data) and approximated the measured one derived from the FCS data. Since self-reported calculations of BMI are underestimated, it is recommended to adjust them to obtain accurate estimates which are important for decision making.
Intentional formation of a protein corona on nanoparticles: Serum concentration affects protein corona mass, surface charge, and nanoparticle-cell interaction.

PubMed

Gräfe, Christine; Weidner, Andreas; Lühe, Moritz V D; Bergemann, Christian; Schacher, Felix H; Clement, Joachim H; Dutz, Silvio

2016-06-01

The protein corona, which immediately is formed after contact of nanoparticles and biological systems, plays a crucial role for the biological fate of nanoparticles. In the here presented study we describe a strategy to control the amount of corona proteins which bind on particle surface and the impact of such a protein corona on particle-cell interactions. For corona formation, polyethyleneimine (PEI) coated magnetic nanoparticles (MNP) were incubated in a medium consisting of fetal calf serum (FCS) and cell culture medium. To modulate the amount of proteins bind to particles, the composition of the incubation medium was varied with regard to the FCS content. The protein corona mass was estimated and the size distribution of the participating proteins was determined by means of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Additionally, the zeta potential of incubated particles was measured. Human blood-brain barrier-representing cell line HBMEC was used for in vitro incubation experiments. To investigate the consequences of the FCS dependent protein corona formation on the interaction of MNP and cells flow cytometry and laser scanning microscopy were used. Zeta potential as well as SDS-PAGE clearly reveal an increase in the amount of corona proteins on MNP with increasing amount of FCS in incubation medium. For MNP incubated with lower FCS concentrations especially medium-sized proteins of molecular weights between 30kDa and 100kDa could be found within the protein corona, whereas for MNP incubated within higher FCS concentrations the fraction of corona proteins of 30kDa and less increased. The presence of the protein corona reduces the interaction of PEI-coated MNP with HBMEC cells within a 30min-incubation. Copyright © 2015 Elsevier Ltd. All rights reserved.
Structural elucidation of fucosylated chondroitin sulfates from sea cucumber using FTICR-MS/MS.

PubMed

Agyekum, Isaac; Pepi, Lauren; Yu, Yanlei; Li, Junhui; Yan, Lufeng; Linhardt, Robert J; Chen, Shiguo; Amster, I Jonathan

2018-02-01

Fucosylated chondroitin sulfates are complex polysaccharides extracted from sea cucumber. They have been extensively studied for their anticoagulant properties and have been implicated in other biological activities. While nuclear magnetic resonance spectroscopy has been used to extensively characterize fucosylated chondroitin sulfate oligomers, we herein report the first detailed mass characterization of fucosylated chondroitin sulfate using high-resolution Fourier transform ion cyclotron resonance mass spectrometry. The two species of fucosylated chondroitin sulfates considered for this work include Pearsonothuria graeffei (FCS-Pg) and Isostichopus badionotus (FCS-Ib). Fucosylated chondroitin sulfate oligosaccharides were prepared by N-deacetylation-deaminative cleavage of the two fucosylated chondroitin sulfates and purified by repeated gel filtration. Accurate mass measurements obtained from electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry measurements confirmed the oligomeric nature of these two fucosylated chondroitin sulfate oligosaccharides with each trisaccharide repeating unit averaging four sulfates per trisaccharide. Collision-induced dissociation of efficiently deprotonated molecular ions through Na/H + exchange proved useful in providing structurally relevant glycosidic and cross-ring product ions, capable of assigning the sulfate modifications on the fucosylated chondroitin sulfate oligomers. Careful examination of the tandem mass spectrometry of both species deferring in the positions of sulfate groups on the fucose residue (FCS-Pg-3,4- OS) and (FCS-Ib-2,4- OS) revealed cross-ring products 0,2 A αf and 2,4 X 2αf which were diagnostic for (FCS-Pg-3,4- OS) and 0,2 X 2αf diagnostic for (FCS-Ib-2,4- OS). Mass spectrometry and tandem mass spectrometry data acquired for both species varying in oligomer length (dp3-dp15) are presented.
Maternal and neonatal service usage and determinants in fragile and conflict-affected situations: a systematic review of Asia and the Middle-East.

PubMed

Gopalan, Saji S; Das, Ashis; Howard, Natasha

2017-03-15

Fragile and conflict-affected situations (FCS) in Asia and the Middle-East contribute significantly to global maternal and neonatal deaths. This systematic review explored maternal and neonatal health (MNH) services usage and determinants in FCS in Asia and the Middle-East to inform policy on health service provision in these challenging settings. This systematic review was conducted using a standardised protocol. Pubmed, Embase, Web of Science, and selected development agency websites were searched for studies meeting inclusion criteria. Studies were assessed for methodological quality using an adapted evaluation tool. Qualitative and quantitative data were synthesized and pooled odds ratios generated for meta-analysis of service-usage determinants. Of 18 eligible peer-reviewed studies, eight were from Nepal, four from Afghanistan, and two each from Iraq, Yemen, and the Palestinian Territories. Fragile situations provide limited evidence on emergency obstetric care, postnatal care, and newborn services. Usage of MNH services was low in all FCS, irrespective of economic growth level. Demand-side determinants of service-usage were transportation, female education, autonomy, health awareness, and ability-to-pay. Supply-side determinants included service availability and quality, existence of community health-workers, costs, and informal payments in health facilities. Evidence is particularly sparse on MNH in acute crises, and remains limited in fragile situations generally. Findings emphasize that poor MNH status in FCS is a leading contributor to the burden of maternal and neonatal ill-health in Asia and the Middle-East. Essential services for skilled birth attendance and emergency obstetric, newborn, and postnatal care require improvement in FCS. FCS require additional resources and policy attention to address the barriers to appropriate MNH care. Authors discuss the 'targeted policy approach for vulnerable groups' as a means of addressing MNH service usage inequities.
Food-coping strategy index applied to a community of farm-worker households in South Africa.

PubMed

Kruger, Rozanne; Schönfeldt, Hettie Carina; Owen, Johanna Hendriena

2008-03-01

In South Africa, households living in informal urban settlements, in rural areas, and on commercial farms experience various levels of dietary variety, food intake, and household hunger. Low incomes, poor food production and availability, and low spending power characterize these households. Households employ various food-coping strategies to alleviate food stress or poor food availability. To apply an existing food-coping strategy (FCS) index to assess household hunger and its usefulness in identifying the level of food stress and the patterns of food coping in farm-worker households. A cross-sectional survey was conducted. Data were gathered from women (18 to 57 years of age) responsible for food provision in a small farm-worker community in Fouriesburg, South Africa. A structured food-coping questionnaire and a standardized FCS index were used to gather data. The two most common FCS used were relying on cheaper food (chicken feet, diluted soya-mince soup) or less preferred food (meat bones) and employing food-seeking strategies (gathering wild foods), followed by consumption of seed stock (maize) and reduced portion sizes (protein foods and side dishes), resulting in starch-based diets of poor variety. Seasonal strategies varied according to the level of food stress experienced. Patterns of food coping were identified. Negative FCS (limiting food choices, only consuming starchy staples) may cause poor health status. The FCS index was effectively used to assess farm-worker household food-coping behavior (early, clear signals of the level of food distress). These results could be used to allocate appropriate food aid (type of food) and to design nutrition education programs focused on positive FCS (food gathering or bartering) in a particular community to prevent suboptimal nutritional status.
The Effects of Leg Kick on Swimming Speed and Arm-Stroke Efficiency in the Front Crawl.

PubMed

Silveira, Ricardo Peterson; de Souza Castro, Flávio Antônio; Figueiredo, Pedro; Vilas-Boas, João Paulo; Zamparo, Paola

2017-07-01

To analyze the effects of swimming pace on the relative contribution of leg kick to swimming speed and to compare arm-stroke efficiency (ηF) assessed when swimming with the arms only (SAO) and while swimming front crawl (FCS) using individual and fixed adjustments to arm-stroke and leg-kick contribution to forward speed. Twenty-nine master swimmers (21 men, 8 women) performed SAO and FCS at 6 self-selected speeds from very slow to maximal. The average swimming speed (v), stroke frequency (SF), and stroke length (SL) were assessed in the central 10 m of the swimming pool. Then, a 2nd-order polynomial regression was used to obtain values of v at paired SF. The percentage difference in v between FCS and SAO, for each paired SF, was used to calculate the relative contributions of the arm stroke (AC) and leg kick (LC) to FCS. Then ηF was calculated using the indirect "paddle-wheel" approach in 3 different ways: using general, individual, and no adjustments to AC. The LC increased with SF (and speed) from -1% ± 4% to 11% ± 1% (P < .05). At the lower FCS speeds, ηF calculated using general adjustments was lower than ηF calculated using individual adjustments (P < .05), but differences disappear at the fastest speeds. Finally, ηF calculated using individual adjustments to LC in the FCS condition did not differ with ηF assessed in the SAO condition at all the investigated speeds. The relative contributions of the arm stroke and leg kick should be individually estimated to reduce errors when calculating arm-stroke efficiency at different speeds and in different swimmers.
CytometryML, an XML format based on DICOM and FCS for analytical cytology data.

PubMed

Leif, Robert C; Leif, Suzanne B; Leif, Stephanie H

2003-07-01

Flow Cytometry Standard (FCS) was initially created to standardize the software researchers use to analyze, transmit, and store data produced by flow cytometers and sorters. Because of the clinical utility of flow cytometry, it is necessary to have a standard consistent with the requirements of medical regulatory agencies. We extended the existing mapping of FCS to the Digital Imaging and Communications in Medicine (DICOM) standard to include list-mode data produced by flow cytometry, laser scanning cytometry, and microscopic image cytometry. FCS list-mode was mapped to the DICOM Waveform Information Object. We created a collection of Extensible Markup Language (XML) schemas to express the DICOM analytical cytologic text-based data types except for large binary objects. We also developed a cytometry markup language, CytometryML, in an open environment subject to continuous peer review. The feasibility of expressing the data contained in FCS, including list-mode in DICOM, was demonstrated; and a preliminary mapping for list-mode data in the form of XML schemas and documents was completed. DICOM permitted the creation of indices that can be used to rapidly locate in a list-mode file the cells that are members of a subset. DICOM and its coding schemes for other medical standards can be represented by XML schemas, which can be combined with other relevant XML applications, such as Mathematical Markup Language (MathML). The use of XML format based on DICOM for analytical cytology met most of the previously specified requirements and appears capable of meeting the others; therefore, the present FCS should be retired and replaced by an open, XML-based, standard CytometryML. Copyright 2003 Wiley-Liss, Inc.
Animal serum-free expansion and differentiation of human mesenchymal stromal cells.

PubMed

Felka, Tino; Schäfer, Richard; De Zwart, Peter; Aicher, Wilhelm K

2010-04-01

Mesenchymal stromal cells (MSC) are attracting increasing interest for possible application in cell therapies. Fetal calf serum (FCS) is widely utilized for cell culture, but its use in the context of clinical applications is associated with too many risks. Therefore we tested FCS-free media for the expansion and differentiation of MSC in compliance with the European good manufacturing practice (GMP) regulations for medicinal products. MSC expansion medium was modified by replacing FCS with human plasma and platelet extract. Cells were characterized according to the defined minimal criteria for multipotent MSC. For chondrogenic differentiation, serum-free micromass cultures were employed. For adipogenic and osteogenic differentiation, the FCS was replaced by human plasma. After 28 days of incubation in differentiation media, cells were analyzed by cytochemical and immunohistochemical staining. Furthermore, mRNA expression of chondrogenic, adipogenic and osteogenic markers was investigated by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Expansion and differentiation of MSC under FCS-free conditions yielded cells with chondrogenic, adipogenic and osteogenic phenotypes and a characteristic gene expression. Chondrocytes in micromass pellets revealed an accumulation of proteoglycans and type II collagen as well as a significantly increased mRNA expression of chondrogenic marker genes. The adipocytes displayed Oil red O staining and expressed peroxisome proliferator-activated receptor gamma(2) (ppARgamma2) and lipoprotein lipase (LPL) mRNA. The osteoblasts were positive for von Kossa staining and expressed mRNA of osteogenic marker genes. The results did not indicate any spontaneous differentiation. Human plasma is a suitable FCS replacement for the expansion and differentiation of MSC, providing a feasible alternative for tissue engineering with GMP-compatible protocols.
A quantum diffusion law

NASA Astrophysics Data System (ADS)

Satpathi, Urbashi; Sinha, Supurna; Sorkin, Rafael D.

2017-12-01

We analyse diffusion at low temperature by bringing the fluctuation-dissipation theorem (FDT) to bear on a physically natural, viscous response-function R(t) . The resulting diffusion-law exhibits several distinct regimes of time and temperature, each with its own characteristic rate of spreading. As with earlier analyses, we find logarithmic spreading in the quantum regime, indicating that this behavior is robust. A consistent R(t) must satisfy the key physical requirements of Wightman positivity and passivity, and we prove that ours does so. We also prove in general that these two conditions are equivalent when the FDT holds. Given current technology, our diffusion law can be tested in a laboratory with ultra cold atoms.
FCS Undergrads at Mississippi State Learn Research Process

ERIC Educational Resources Information Center

Worthy, Sheri L.

2009-01-01

Understanding the research process is a vital part of the undergraduate experience. Conducting research helps students see the value of the scientific process and various research methods, and encourages inquisitiveness about family and consumer sciences (FCS) issues. Research experiences augment students' professional development, increase their…
Sustaining FCS in Higher Education: A 2010 Perspective

ERIC Educational Resources Information Center

Firebaugh, Francille M.; Nickols, Sharon Y.; Atiles, Jorge H.; Turkki, Kaija

2010-01-01

This article identifies characteristics of enduring FCS higher education programs and explores organizational changes and the impact of these changes. From multiple sources, characteristics of sustained programs were identified and categorized as (a) resource-based: strong leadership, outstanding faculty, adequate resources; (b) program-related:…
Fucoidan and Fucosylated Chondroitin Sulfate Stimulate Hematopoiesis in Cyclophosphamide-Induced Mice.

PubMed

Anisimova, Natalia; Ustyuzhanina, Nadezhda; Bilan, Maria; Donenko, Fedor; Usov, Anatolii; Kiselevskiy, Mikhail; Nifantiev, Nikolay

2017-09-30

Application of cytostatics in cancer patients' chemotherapy results in a number of side effects, including the inhibition of various parts of hematopoiesis. Two sulfated polysaccharides, fucoidan from the seaweed Chordaria flagelliformis ( PS-Fuc ) and fucosylated chondroitin sulfate from the sea cucumber Massinium magnum ( PS-FCS ), were studied as stimulators of hematopoiesis after cyclophosphamide immunosuppression in mice. Recombinant granulocyte colony-stimulating factor ( r G-CSF ) was applied as a reference. Both tested polysaccharides PS-Fuc and PS-FCS have a similar activity to r G-CSF , causing pronounced neutropoiesis stimulation in animals with myelosuppression induced by cyclophosphamide ( CPh ). Moreover, these compounds are also capable to enhance thrombopoiesis and erythropoiesis. It should be noted that PS-FCS demonstrated a greater activity than r G-CSF . The results indicate the perspective of further studies of PS-Fuc and PS-FCS , since these compounds can be considered as potentially promising stimulators of hematopoiesis. Such drugs are in demand for the accompanying treatment of cancer patients who suffer from hematological toxicity during chemo and/or radiation therapy.
Study of Method for Designing the Power and the Capacitance of Fuel Cells and Electric Double-Layer Capacitors of Hybrid Railway Vehicle

NASA Astrophysics Data System (ADS)

Takizawa, Kenji; Kondo, Keiichiro

A hybrid railway traction system with fuel cells (FCs) and electric double layer-capacitors (EDLCs) is discussed in this paper. This system can save FC costs and absorb the regenerative energy. A method for designing FCs and EDLCs on the basis of the output power and capacitance, respectively, has not been reported, even though their design is one of the most important technical issues encountered in the design of hybrid railway vehicles. Such design method is presented along with a train load profile and an energy management strategy. The design results obtained using the proposed method are verified by performing numerical simulations of a running train. These results reveal that the proposed method for designing the EDLCs and FCs on the basis of the capacitance and power, respectively, and by using a method for controlling the EDLC voltage is sufficiently effective in designing efficient EDLCs and FCs of hybrid railway traction systems.
Effects of flow modification on a cattail wetland at the mouth of Irondequoit Creek near Rochester, New York: Water levels, wetland biota, sediment, and water quality

USGS Publications Warehouse

Coon, William F.

2004-01-01

An 11-year (1990-2001) study of the Ellison Park wetland, a 423-acre, predominantly cattail (Typha glauca) wetland at the mouth of Irondequoit Creek, was conducted to document the effects that flow modifications, including installation of a flow-control structure (FCS) in 1997 and increased diversion of stormflows to the backwater areas of the wetland, would have on the wetland's ability to decrease chemical loads transported by Irondequoit Creek into Irondequoit Bay on Lake Ontario. The FCS was designed to raise the water-surface elevation and thereby increase the dispersal and detention of stormflows in the upstream half of the wetland; this was expected to promote sedimentation and microbial utilization of nutrients, and thereby decrease the loads of certain constituents, primarily phosphorus, that would otherwise be carried into Irondequoit Bay. An ecological monitoring program was established to document changes in the wetland's water levels, biota, sedimentation rates, and chemical quality of water and sediment that might be attributable to the flow modifications.Water-level increases during storms were mostly confined to the wetland area, within about 5,000 ft upstream from the FCS. Backwater at a point of local concern, about 13,000 ft upstream, was due to local debris jams or constriction of flow by bridges and was not attributable to the FCS.Plant surveys documented species richness, concentrations of nutrients and metals in cattail tissues, and cattail productivity. Results indicated that observed differences among survey periods and between the areas upstream and downstream from the FCS were due to seasonal changes in water levels—either during the current year or at the end of the previous year's growing season—that reflected the water-surface elevation of Lake Ontario, rather than water-level control by the FCS. Results showed no adverse effects from the naturally high water levels that prevail annually during the spring and summer in the wetland, nor from the short-duration increases in water levels that result from FCS operation. Fish surveys documented the use of the wetland by 44 species, of which 25 to 29 species were found in any given year. Community composition was relatively consistent during the study, but seasonal and year-to-year variations in dominant resident and nonresident species were noted, and probably reflected natural or regional population patterns in Lake Ontario and Irondequoit Bay. The FCS allowed fish passage at all water levels and had no discernible adverse effect on the fish community.Bird surveys documented the use of the wetland by more than 90 species for breeding, feeding, and migration. Ground-nesting birds were unaffected by the FCS. Seasonally high water levels, rather than short-duration increases caused by the FCS, might have caused the scarcity or absence of certain wetland species by limiting the extent of breeding habitat for some species and the exposure of mud flats that attracted other species. Some noticeably scarce or absent species also were rare or absent elsewhere along the south-central shore of Lake Ontario.Benthic-macroinvertebrate studies were of minimal use for evaluating the effect of the FCS because no surveys were conducted after FCS installation. The precontrol results allowed assessment of the ecological quality of the wetland on the basis of biotic indices, and generally indicated moderately to severely impaired conditions. Differences between the macroinvertebrate communities in the southern part of the wetland and those in the northern part were attributed to habitat differences, such as substrate composition, water depth, and density of submerged aquatic vegetation.Sedimentation rates in the areas upstream and downstream from the FCS increased after the flow modifications, more in the area upstream from the FCS than in the downstream area. The concurrent downstream increase and the dynamic patterns of deposition and scour indicated that although the FCS and the other flow modifications undoubtedly were major factors in the postcontrol upstream increase in sedimentation rates, other factors, such as the magnitude, frequency, and the timing (season) of peak flows, might also have contributed.Periodic analyses of sediment samples from three longterm depositional sites in the wetland documented the concentrations of major and trace elements, polycyclic aromatic hydrocarbons, and organochlorine and organophosphate compounds. The concentrations of most constituents showed no substantial fluctuation or consistent upward or downward trend during the years sampled, nor did they identify any change after FCS installation. Comparison of the measured concentrations with sediment-quality guidelines that are used to assess the ecological quality of substrate environments indicated that the wetland was moderately to severely impaired—an assessment consistent with the benthic-macroinvertebrate biotic indices.During the precontrol period (1990–96), the wetland was a sink for particulate constituents (removal efficiencies for total phosphorus and total suspended solids were 28 and 47 percent, respectively), but had little effect on conservative constituents (chloride and sulfate). The wetland was a source of orthophosphate and ammonia (removal efficiencies were -38 and -84 percent, respectively).During the postcontrol period (1997–2001), the wetland continued to be a sink for particulate constituents (removal efficiencies for total phosphorus and total suspended solids were 45 and 52 percent, respectively); the exportation of orthophosphate by the wetland decreased (by 7 percent), whereas that of ammonia increased (by about 70 percent). The outflow loads of orthophosphate and ammonia represented about 15 and 2.3 percent of total phosphorus and total nitrogen loads, respectively. Changes in the loads of conservative constituents were negligible, and the overall removal efficiencies for other constituents during the precontrol period differed from those of the postcontrol period by no more than 5.4 percent.Statistical analyses of monthly inflow and outflow loads indicated significant differences between inflow and outflow loads of most constituents during the pre- and postcontrol periods. Load data were adjusted to remove the effects of dissimilar hydrologic conditions that prevailed during the pre- and postcontrol periods, and to isolate the water-quality-improvement effect that could be attributed solely to the FCS. Results indicated that the FCS contributed significantly to the decrease in total phosphorus loads, and slightly to a decrease in ammonia-plus-organic nitrogen loads, but had little or no significant effect on loads of other constituents.
Epidemiological and virological differences in human clustered and sporadic infections with avian influenza A H7N9.

PubMed

Wu, Zuqun; Sha, Jianping; Yu, Zhao; Zhao, Na; Cheng, Wei; Chan, Ta-Chien; Amer, Said; Zhang, Zhiruo; Liu, Shelan

2016-08-01

Previous research has suggested that avian influenza A H7N9 has a greater potential pandemic risk than influenza A H5N1. This research investigated the difference in human clustered and sporadic cases of H7N9 virus and estimated the relative risk of clustered infections. Comparative epidemiology and virology studies were performed among 72 sporadic confirmed cases, 17 family clusters (FCs) caused by human-to-human transmission, and eight live bird market clusters (LCs) caused by co-exposure to the poultry environment. The case fatality of FCs, LCs and sporadic cases (36%, 26%, and 29%, respectively) did not differ among the three groups (p>0.05). The average age (36 years, 60 years, and 58 years), co-morbidities (31%, 60%, and 54%), exposure to birds (72%, 100%, and 83%), and H7N9-positive rate (20%, 64%, and 35%) in FCs, LCs, and sporadic cases, respectively, differed significantly (p<0.05). These higher risks were associated with increased mortality. There was no difference between primary and secondary cases in LCs (p>0.05). However, exposure to a person with confirmed avian influenza A H7N9 (primary 12% vs. secondary 95%), history of visiting a live bird market (100% vs. 59%), multiple exposures (live bird exposure and human-to-human transmission history) (12% vs. 55%), and median days from onset to antiviral treatment (6 days vs. 3 days) differed significantly between primary and secondary cases in FCs (p<0.05). Mild cases were found in 6% of primary cases vs. 32% of secondary cases in FCs (p<0.05). Twenty-five isolates from the three groups showed 99.1-99.9% homology and increased human adaptation. There was no statistical difference in the case fatality rate and limited transmission between FCs and LCs. However, the severity of the primary cases in FCs was much higher than that of the secondary cases due to the older age and greater underlying disease of the latter patients. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.
Collaboration: Perceptions of FCS Professionals in Teaching, Research, and Service

ERIC Educational Resources Information Center

Kandiah, Jay; Saiki, Diana

2012-01-01

The purpose of this study is to investigate family and consumer sciences (FCS) professionals' perceptions of multidisciplinary collaboration in teaching, research, and service. A focus group and survey were participants identified projects, strengths, weaknesses, and suggestions related to collaboration.Topics and projects that incorporated…
Historical Research: A Lens for Family and Consumer Sciences

ERIC Educational Resources Information Center

Nickols, Sharon Y.

2017-01-01

This article describes various historical research methods and presents examples of their application in family and consumer sciences (FCS). Historical research preserves the heritage of FCS through greater understanding of the development of the field and practitioners of the profession. Furthermore, historical research can revitalize…
Leadership Unit Added to FCS Intro Course

ERIC Educational Resources Information Center

Walker, Jane

2006-01-01

Many undergraduate students entering family and consumer sciences (FCS) will become leaders in the profession and may have limited opportunity for formal education in leadership development. Would these budding leaders develop skills faster or move into leadership roles with greater confidence and enthusiasm if they began their undergraduate…
Developing Potential for Entrepreneurship in FCS

ERIC Educational Resources Information Center

Niehm, Linda S.; Gregoire, Mary B.; Austin, Tanya; Mhango, Mary

2005-01-01

Guided by national, state, and university initiatives to promote rural entrepreneurship, faculty in Iowa State University's College of Family and Consumer Sciences (FCS) were awarded funding from the Kauffman Foundation and Pappajohn Center to expand their work in entrepreneurship education. A series of multi-unit learning modules was developed…
Unique Microbial Phylotypes in Namib Desert Dune and Gravel Plain Fairy Circle Soils.

PubMed

van der Walt, Andries J; Johnson, Riegardt M; Cowan, Don A; Seely, Mary; Ramond, Jean-Baptiste

2016-08-01

Fairy circles (FCs) are barren circular patches of soil surrounded by grass species. Their origin is poorly understood. FCs feature in both the gravel plains and the dune fields of the Namib Desert. While a substantial number of hypotheses to explain the origin and/or maintenance of fairy circles have been presented, none are completely consistent with either their properties or their distribution. In this study, we investigated the hypothesis that FC formation in dunes and gravel plains is due to microbial phytopathogenesis. Surface soils from five gravel plain and five dune FCs, together with control soil samples, were analyzed using high-throughput sequencing of bacterial/archaeal (16S rRNA gene) and fungal (internal transcribed spacer [ITS] region) phylogenetic markers. Our analyses showed that gravel plain and dune FC microbial communities are phylogenetically distinct and that FC communities differ from those of adjacent vegetated soils. Furthermore, various soil physicochemical properties, particularly the pH, the Ca, P, Na, and SO4 contents, the soil particle size, and the percentage of carbon, significantly influenced the compositions of dune and gravel plain FC microbial communities, but none were found to segregate FC and vegetated soil communities. Nevertheless, 9 bacterial, 1 archaeal, and 57 fungal phylotypes were identified as FC specific, since they were present within the gravel plain and dune FC soils only, not in the vegetated soils. Some of these FC-specific phylotypes were assigned to taxa known to harbor phytopathogenic microorganisms. This suggests that these FC-specific microbial taxa may be involved in the formation and/or maintenance of Namib Desert FCs. Fairy circles (FCs) are mysterious barren circular patches of soil found within a grass matrix in the dune fields and gravel plains of the Namib Desert. Various hypotheses attempting to explain this phenomenon have been proposed. To date, however, none have been successful in fully explaining the etiology of FCs, particularly since gravel plain FCs have been largely ignored. In this study, we investigated the hypothesis that microorganisms could be involved in the FC phenomenon through phytopathogenesis. We show that the microbial communities in FC and control vegetated soil samples were significantly different. Furthermore, we detected 67 FC-specific microbial phylotypes, i.e., phylotypes present solely in both gravel plain and dune FC soils, some of which were closely related to known phytopathogens. Our results, therefore, demonstrate that microorganisms may play a role in the formation and/or maintenance of Namib Desert FCs, possibly via phytopathogenic activities. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Competition of the connectivity with the local and the global order in polymer melts and crystals

NASA Astrophysics Data System (ADS)

Bernini, S.; Puosi, F.; Barucco, M.; Leporini, D.

2013-11-01

The competition between the connectivity and the local or global order in model fully flexible chain molecules is investigated by molecular-dynamics simulations. States with both missing (melts) and high (crystal) global order are considered. Local order is characterized within the first coordination shell (FCS) of a tagged monomer and found to be lower than in atomic systems in both melt and crystal. The role played by the bonds linking the tagged monomer to FCS monomers (radial bonds), and the bonds linking two FCS monomers (shell bonds) is investigated. The detailed analysis in terms of Steinhardt's orientation order parameters Ql (l = 2 - 10) reveals that increasing the number of shell bonds decreases the FCS order in both melt and crystal. Differently, the FCS arrangements organize the radial bonds. Even if the molecular chains are fully flexible, the distribution of the angle formed by adjacent radial bonds exhibits sharp contributions at the characteristic angles θ ≈ 70°, 122°, 180°. The fractions of adjacent radial bonds with θ ≈ 122°, 180° are enhanced by the global order of the crystal, whereas the fraction with 70° ≲ θ ≲ 110° is nearly unaffected by the crystallization. Kink defects, i.e., large lateral displacements of the chains, are evidenced in the crystalline state.
What do family caregivers of Alzheimer's disease patients desire in smart home technologies? Contrasted results of a wide survey.

PubMed

Rialle, V; Ollivet, C; Guigui, C; Hervé, C

2008-01-01

The authors' aim was to investigate the representations, wishes, and fears of family caregivers (FCs) regarding 14 innovative technologies (IT) for care aiding and burden alleviation, given the severe physical and psychological stress induced by dementia care, and the very slow uptake of these technologies in our society. A cluster sample survey based on a self-administered questionnaire was carried out on data collected from 270 families of patients with Alzheimer's disease or related disorders, located in the greater Paris area. Multiple Correspondence Analysis was used in addition to usual statistical tests to identify homogenous FCs clusters concerning the appreciation or rejection of the considered technologies. Two opposite clusters were clearly defined: FCs in favor of a substantial use of technology, and those rather or totally hostile. Furthermore the distributions of almost all the answers of appreciations were U-shaped. Significant relations were demonstrated between IT appreciation and FC's family or gender statuses (e.g., female FCs appreciated a tracking device for quick recovering of wandering patients more than male FCs: p = 0.0025, N = 195). The study provides further evidence of the contrasted perception of technology in dementia care at home, and suggests the development of public debates based on rigorous assessment of practices and a strict ethical aim to protect against misuse.
Synthesis of the oligosaccharides related to branching sites of fucosylated chondroitin sulfates from sea cucumbers.

PubMed

Ustyuzhanina, Nadezhda E; Fomitskaya, Polina A; Gerbst, Alexey G; Dmitrenok, Andrey S; Nifantiev, Nikolay E

2015-02-02

Natural anionic polysaccharides fucosylated chondroitin sulfates (FCS) from sea cucumbers attract great attention nowadays due to their ability to influence various biological processes, such as blood coagulation, thrombosis, angiogenesis, inflammation, bacterial and viral adhesion. To determine pharmacophore fragments in FCS we have started systematic synthesis of oligosaccharides with well-defined structure related to various fragments of these polysaccharides. In this communication, the synthesis of non-sulfated and selectively O-sulfated di- and trisaccharides structurally related to branching sites of FCS is described. The target compounds are built up of propyl β-d-glucuronic acid residue bearing at O-3 α-l-fucosyl or α-l-fucosyl-(1→3)-α-l-fucosyl substituents. O-Sulfation pattern in the fucose units of the synthetic targets was selected according to the known to date holothurian FCS structures. Stereospecific α-glycoside bond formation was achieved using 2-O-benzyl-3,4-di-O-chloroacetyl-α-l-fucosyl trichloroacetimidate as a donor. Stereochemical outcome of the glycosylation was explained by the remote participation of the chloroacetyl groups with the formation of the stabilized glycosyl cations, which could be attacked by the glycosyl acceptor only from the α-side. The experimental results were in good agreement with the SCF/MP2 calculated energies of such participation. The synthesized oligosaccharides are regarded as model compounds for the determination of a structure-activity relationship in FCS.
Synthesis of the Oligosaccharides Related to Branching Sites of Fucosylated Chondroitin Sulfates from Sea Cucumbers

PubMed Central

Ustyuzhanina, Nadezhda E.; Fomitskaya, Polina A.; Gerbst, Alexey G.; Dmitrenok, Andrey S.; Nifantiev, Nikolay E.

2015-01-01

Natural anionic polysaccharides fucosylated chondroitin sulfates (FCS) from sea cucumbers attract great attention nowadays due to their ability to influence various biological processes, such as blood coagulation, thrombosis, angiogenesis, inflammation, bacterial and viral adhesion. To determine pharmacophore fragments in FCS we have started systematic synthesis of oligosaccharides with well-defined structure related to various fragments of these polysaccharides. In this communication, the synthesis of non-sulfated and selectively O-sulfated di- and trisaccharides structurally related to branching sites of FCS is described. The target compounds are built up of propyl β-d-glucuronic acid residue bearing at O-3 α-l-fucosyl or α-l-fucosyl-(1→3)-α-l-fucosyl substituents. O-Sulfation pattern in the fucose units of the synthetic targets was selected according to the known to date holothurian FCS structures. Stereospecific α-glycoside bond formation was achieved using 2-O-benzyl-3,4-di-O-chloroacetyl-α-l-fucosyl trichloroacetimidate as a donor. Stereochemical outcome of the glycosylation was explained by the remote participation of the chloroacetyl groups with the formation of the stabilized glycosyl cations, which could be attacked by the glycosyl acceptor only from the α-side. The experimental results were in good agreement with the SCF/MP2 calculated energies of such participation. The synthesized oligosaccharides are regarded as model compounds for the determination of a structure-activity relationship in FCS. PMID:25648510
FRAP to Characterize Molecular Diffusion and Interaction in Various Membrane Environments.

PubMed

Pincet, Frédéric; Adrien, Vladimir; Yang, Rong; Delacotte, Jérôme; Rothman, James E; Urbach, Wladimir; Tareste, David

2016-01-01

Fluorescence recovery after photobleaching (FRAP) is a standard method used to study the dynamics of lipids and proteins in artificial and cellular membrane systems. The advent of confocal microscopy two decades ago has made quantitative FRAP easily available to most laboratories. Usually, a single bleaching pattern/area is used and the corresponding recovery time is assumed to directly provide a diffusion coefficient, although this is only true in the case of unrestricted Brownian motion. Here, we propose some general guidelines to perform FRAP experiments under a confocal microscope with different bleaching patterns and area, allowing the experimentalist to establish whether the molecules undergo Brownian motion (free diffusion) or whether they have restricted or directed movements. Using in silico simulations of FRAP measurements, we further indicate the data acquisition criteria that have to be verified in order to obtain accurate values for the diffusion coefficient and to be able to distinguish between different diffusive species. Using this approach, we compare the behavior of lipids in three different membrane platforms (supported lipid bilayers, giant liposomes and sponge phases), and we demonstrate that FRAP measurements are consistent with results obtained using other techniques such as Fluorescence Correlation Spectroscopy (FCS) or Single Particle Tracking (SPT). Finally, we apply this method to show that the presence of the synaptic protein Munc18-1 inhibits the interaction between the synaptic vesicle SNARE protein, VAMP2, and its partner from the plasma membrane, Syn1A.
A Tale of Two Fishes or a Quick Fix for Fick's Law

ERIC Educational Resources Information Center

Robischon, Marcel A.

2014-01-01

Gas diffusion, as a basis for complex biological processes such as respiration, is a core principle for understanding fundamental physiology. Students, however, often find these concepts challenging, in particular when expressed formally as in Fick's law of gas diffusion. This introduction to Fick's law uses the representations of…
The Optical-Mid-infrared Extinction Law of the l = 165° Sightline in the Galactic Plane: Diversity of the Extinction Law in the Diffuse Interstellar Medium

NASA Astrophysics Data System (ADS)

Wang, Shu; Jiang, B. W.; Zhao, He; Chen, Xiaodian; de Grijs, Richard

2017-10-01

Understanding the effects of dust extinction is important to properly interpret observations. The optical total-to-selective extinction ratio, {R}V={A}V/E(B-V), is widely used to describe extinction variations in ultraviolet and optical bands. Since the {R}V=3.1 extinction curve adequately represents the average extinction law of diffuse regions in the Milky Way, it is commonly used to correct observational measurements along sightlines toward diffuse regions in the interstellar medium. However, the {R}V value may vary even along different diffuse interstellar medium sightlines. In this paper, we investigate the optical-mid-infrared (mid-IR) extinction law toward a very diffuse region at l=165^\\circ in the Galactic plane, which was selected based on a CO emission map. Adopting red clump stars as extinction tracers, we determine the optical-mid-IR extinction law for our diffuse region in two APASS bands (B,V), three XSTPS-GAC bands (g,r,I), three 2MASS bands (J,H,{K}s), and two WISE bands (W1,W2). Specifically, 18 red clump stars were selected from the APOGEE-RC catalog based on spectroscopic data in order to explore the diversity of the extinction law. We find that the optical extinction curves exhibit appreciable diversity. The corresponding {R}V ranges from 1.7 to 3.8, while the mean {R}V value of 2.8 is consistent with the widely adopted average value of 3.1 for Galactic diffuse clouds. There is no apparent correlation between {R}V value and color excess E(B-V) in the range of interest, from 0.2 to 0.6 mag, or with specific visual extinction per kiloparsec, {A}V/d.
Family and Consumer Sciences and STEM Integration

ERIC Educational Resources Information Center

Carter, Vinson; Beachner, Maggie; Daugherty, Michael K.

2015-01-01

Family and consumer sciences (FCS) education has traditionally attracted a large percentage of female students (Vincenti, 1997; Werhan, 2013). Werhan (2013) reported that slightly less than 3.5 million students are engaged in FCS courses, and at the high school level, approximately 65% of them are female. This skewed representation of female…
Promoting a Healthy Body: Collaboration among FCS Majors

ERIC Educational Resources Information Center

Yoo, Jeong-Ju

2011-01-01

Family and consumer sciences (FCS) professionals educate leaders who will contribute to the well-being of individuals, families, and communities. A description of a collaborative classroom project designed to enhance students' understanding of healthy body images is shared. Students are provided with opportunities to work with their collegiate…
Research in the FCS Secondary Classroom

ERIC Educational Resources Information Center

McCord, Olivia Love; Brown, Lora Beth

2009-01-01

Much of what is taught in the family and consumer sciences (FCS) classroom is based on scientific research. The existing knowledge base is so broad that overlooking research as a teaching resource and tool happens often. Research enhances what is taught, thereby improving the effectiveness of teachers. Whether it be applying or translating…
The Living Gender Curriculum: Helping FCS Students Analyze Gender Stereotypes

ERIC Educational Resources Information Center

Goldstein-Schultz, Martha

2016-01-01

The concept of gender stereotypes permeates the lives of youth in the United States. This article provides background information and rationale for incorporating gender stereotype analysis into family and consumer sciences (FCS) coursework. The critical analysis of gender stereotypes includes numerous activities and assessments that encourage…
Proactive Recruitment Strategies at CSUS Increase FCS Majors

ERIC Educational Resources Information Center

Malroutu, Y. Lakshmi; Tripp, Paula J.

2008-01-01

The profile and needs of today's undergraduate students have changed, and family and consumer sciences (FCS) departments will benefit from taking a proactive approach to adjust their recruitment strategies to meet those needs. California State University, Sacramento, implemented successful efforts in the areas of virtual contact, direct contact,…
AAFCS Resources for Elevating Research and Scholarship in FCS

ERIC Educational Resources Information Center

Myers, Lori A.

2017-01-01

Elevating research and supporting scholarship are both a responsibility and core value of all family and consumer sciences (FCS) professionals. This responsibility may involve: (1) Introducing the research process under graduate students; (2) Guiding the research of graduate students; (3) Mentoring a junior faculty member to establish a research…
Community Health: FCS Extension Educators Deliver Diabetes Education in PA

ERIC Educational Resources Information Center

Cox, Jill N.; Corbin, Marilyn

2011-01-01

For decades, family and consumer sciences (FCS) Extension educators have provided health related education to consumers through Cooperative Extension programming at land grant universities. However, offering diabetes education can be extra challenging due to the complicated nature of the disease and the multi-faceted treatment required. Faced with…
Improving FCS Accountability: Increasing STEM Awareness with Interior Design Modules

ERIC Educational Resources Information Center

Etheredge, Jessica; Moody, Dana; Cooper, Ashley

2014-01-01

This paper demonstrates ways in which family and consumer sciences (FCS) educators can explore more opportunities to integrate Science, Technology, Engineering, and Math (STEM) principles into secondary education curriculum. Interior design is used as a case study for creating learning modules that incorporate STEM principles in a creative and…
High School FCS Program Reaches Out to Senior Citizens

ERIC Educational Resources Information Center

Sowers, Margaret A.

2007-01-01

"Bridging the Gap: Intergenerational Appreciation" is an educational partnership between community residents and high school family and consumer sciences (FCS) students in the Cornwall-Lebanon School District in Lebanon, Pennsylvania. The program provides 10th, 11th, and 12th grade students opportunities to be actively involved with the…
Enriching Inclusive Learning: African Americans in Historic Costume

ERIC Educational Resources Information Center

Ratute, Ashley; Marcketti, Sara B.

2009-01-01

Educating students to embrace diversity and value all people is a core value of educators in family and consumer sciences (FCS). For instructors in FCS, integrating the contributions of African Americans--particularly in textiles and clothing--can be an inclusive learning opportunity. The authors compiled resources on African Americans and…
Exploring Spirituality of University FCS Students: A Resource for Resiliency

ERIC Educational Resources Information Center

Rehm, Marsha L.; Allison, Barbara N.

2009-01-01

This interview study explored the role of spirituality in the career preparation experiences of 25 university family and consumer sciences (FCS) students. All participants viewed spirituality as both a steadfast higher power and a flexible resource for providing resiliency. Participants believed their career-related experiences were meaningful…
FCS Global Perspectives in a General Education Course

ERIC Educational Resources Information Center

Weiner, Anne

2010-01-01

General education requirements have long been a component of college and university baccalaureate programs. The courses have traditionally focused on the disciplines in the arts and sciences including mathematics, sciences, humanities, social sciences, and the arts. Family and consumer sciences (FCS) programs also offer courses in areas such as…
Private Source Funding for FCS Units

ERIC Educational Resources Information Center

Winchip, Susan M.

2004-01-01

Financial difficulties have prompted institutions of higher education to explore private sources of funding. In recent years, public institutions have significantly increased their focus on private giving, with several campaigns having more than $1 billion as a goal. Family and consumer sciences (FCS) professionals need to be actively involved in…

Creative Problem-Solving Exercises and Training in FCS

ERIC Educational Resources Information Center

Marcketti, Sara B.; Karpova, Elena; Barker, Jessica

2009-01-01

Creative problem-solving has been linked to successful adjustment to the demands of daily life. The ability to recognize problems as opportunities can be an essential skill when dealing with uncertainty and adapting to continuous changes, both in personal and professional lives. Family and consumer sciences (FCS) professionals should strive to…
Accountability of FCS Education to a Sustainability Ethos: Focus on Sustainable Consumption

ERIC Educational Resources Information Center

Wuest, Beth; Hustvedt, Gwendolyn; Kang, Jiyun

2014-01-01

The American Association of Family & Consumer Sciences' (AAFCS) brand, "creating healthy and sustainable families," implies accountability in promoting sustainable consumer behavior. This study compared students majoring in family and consumer sciences (FCS) and its specializations to those majoring in other fields on constructs of…
The Role of Museum Exhibits in Teaching Textile Science

ERIC Educational Resources Information Center

Diddi, Sonali; Marcketti, Sara B.

2014-01-01

The concept of learning outside of the traditional, formal classroom setting is an important component of family and consumer sciences (FCS) educational pedagogy. Methods of learning beyond the FCS classroom include visiting museums, accessing archives--both in person and virtually--and participating in field studies (Roehl, 2013). Although many…
Serving Clientele with Disabilities: An Assessment of Texas FCS Agents' Needs for Implementing Inclusive Programs

ERIC Educational Resources Information Center

Peterson, Rick L.; Grenwelge, Cheryl; Benz, Michael R.; Zhang, Dalun; Resch, J. Aaron; Mireles, Gerardo; Mahadevan, Lakshmi

2012-01-01

This article reports on a qualitative study to assess Texas Family Consumer Science (FCS) Extension professionals' experiences working with individuals with disabilities and their perceived skills in promoting and delivering inclusive educational programming for this audience. Study results indicate that overall Extension educators viewed…
Dynamic Leadership, Character Education Form New FCS Class

ERIC Educational Resources Information Center

Watkins, Carol Ann

2007-01-01

In this article, the author describes the leadership class that she created for the family and consumer sciences (FCS) department. The class, "Family & Consumer Sciences Issues & Applications," focused on family and community action for improved quality of life. It included in-depth laboratory experiences, service learning activities, and the…
Transport in Nanoporous Materials Including MOFs: The Applicability of Fick's Laws.

PubMed

Titze, Tobias; Lauerer, Alexander; Heinke, Lars; Chmelik, Christian; Zimmermann, Nils E R; Keil, Frerich J; Ruthven, Douglas M; Kärger, Jörg

2015-11-23

Diffusion in nanoporous host-guest systems is often considered to be too complicated to comply with such "simple" relationships as Fick's first and second law of diffusion. However, it is shown herein that the microscopic techniques of diffusion measurement, notably the pulsed field gradient (PFG) technique of NMR spectroscopy and microimaging by interference microscopy (IFM) and IR microscopy (IRM), provide direct experimental evidence of the applicability of Fick's laws to such systems. This remains true in many situations, even when the detailed mechanism is complex. The limitations of the diffusion model are also discussed with reference to the extensive literature on this subject. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Influence of La/W ratio on electrical conductivity of lanthanum tungstate with high La/W ratio

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kojo, Gen; Shono, Yohei; Ushiyama, Hiroshi

The proton-conducting properties of lanthanum tungstates (LWOs) with high La/W ratios were investigated using electrochemical measurements and quantum chemical calculations. Single phases of LWOs with high La/W ratios (6.3≤La/W≤6.7) were synthesized by high-temperature sintering at around 1700 °C. The electrical conductivity of LWO increased with increasing La/W ratio in the single-phase region. The LWO synthesized at the optimum sintering temperature and time, and with the optimum La/W ratio gave the maximum conductivity, i.e., 2.7×10{sup −3} S cm{sup −1} with La/W=6.7 at 500 °C. Density functional theory calculations, using the nudged elastic band method, were performed to investigate the proton diffusionmore » barrier. The results suggest that the proton diffusion paths around La sites have the lowest proton diffusion barrier. These findings improve our understanding of LWO synthesis and the proton-conducting mechanism and provide a strategy for improving proton conduction in LWOs. - Graphical abstract: The LWOs with high La/W ratios were synthesized for the first time. The optimum La/W ratio gave the maximum conductivity with La/W=6.7 at 500 °C. The proton diffusion paths were also considered with density functional theory calculations. - Highlights: • The proton-conducting properties of lanthanum tungstates (LWOs) were investigated. • Single phase LWOs with high La/W ratios (6.3≤La/W≤6.7) were synthesized successfully. • LWOs with the high La/W ratios showed high proton conductivity. • The DFT calculation suggested the lowest proton diffusion barrier in the path around La sites.« less
A quantitative analysis of the F18 flight control system

NASA Technical Reports Server (NTRS)

Doyle, Stacy A.; Dugan, Joanne B.; Patterson-Hine, Ann

1993-01-01

This paper presents an informal quantitative analysis of the F18 flight control system (FCS). The analysis technique combines a coverage model with a fault tree model. To demonstrate the method's extensive capabilities, we replace the fault tree with a digraph model of the F18 FCS, the only model available to us. The substitution shows that while digraphs have primarily been used for qualitative analysis, they can also be used for quantitative analysis. Based on our assumptions and the particular failure rates assigned to the F18 FCS components, we show that coverage does have a significant effect on the system's reliability and thus it is important to include coverage in the reliability analysis.
Placemaking: An Engaged Approach to Community Well-Being

ERIC Educational Resources Information Center

Ellery, Jane; Ellery, Peter; MacKenzie, Annah; Friesen, Carol

2017-01-01

For more than a century, improving the quality of life for individuals, families, and communities has been the cornerstone of the work of family and consumer sciences (FCS) professionals. This began with our founder, Dr. Ellen Swallow Richards, and it continues today. As FCS professionals, we focus on helping people make wise, informed decisions…
Transforming Individuals, Families, and Communities through Travel

ERIC Educational Resources Information Center

Austin, Tanya

2006-01-01

It was predicted that the 21st century would be an era of family stress and transformation (McCubbin, McCubbin, Thompson, Han, & Allen, 1997). When evaluating what families face today and what FCS professionals are addressing in current research, curriculum, and programming, it seems that this is indeed the case. Today's FCS professionals need to…
FCS Teacher Takes on Obesity Epidemic

ERIC Educational Resources Information Center

Carlton, Toni

2007-01-01

Fighting the childhood obesity problem at Mayfield Middle School is an ongoing campaign. As a family and consumer sciences (FCS) teacher, the author decided to go outside the box to teach students and their families how to cook healthy dishes, eat a balanced and nutritious diet, and exercise regularly. All students at Mayfield attend a 6-week…
FCS and English: Dual Class Develops "Taste" for Other Cultures

ERIC Educational Resources Information Center

Caya, Billie Ann

2005-01-01

"Foods and Literature of the World" is a dual class taught at Bismarck High School in Bismarck, North Dakota. There are two components of the class--English and family and consumer sciences (FCS). (The English component fulfills the 12th grade English requirement.) Culture is explored through class discussion, essay writing, research,…
A Comparison of Joint Model and Fully Conditional Specification Imputation for Multilevel Missing Data

ERIC Educational Resources Information Center

Mistler, Stephen A.; Enders, Craig K.

2017-01-01

Multiple imputation methods can generally be divided into two broad frameworks: joint model (JM) imputation and fully conditional specification (FCS) imputation. JM draws missing values simultaneously for all incomplete variables using a multivariate distribution, whereas FCS imputes variables one at a time from a series of univariate conditional…
Heart of the FCS Body of Knowledge: Relational Ethic

ERIC Educational Resources Information Center

Roubanis, Jody L.

2016-01-01

The Family and Consumer Sciences Body of Knowledge (FCS-BOK) provides an ideological stance that is universal to all practitioners of the profession, and it has major implications for the normative ethics that guide professional practice. The purpose of this article is to outline a conceptual framework to reveal the relational ethic inherent in…
Merchandising's Evolving Role in Family and Consumer Sciences

ERIC Educational Resources Information Center

Sullivan, Pauline; Collier, Billie J.; Goldsmith, Elizabeth B.

2011-01-01

Merchandising and consumer economics traditionally have been part of family and consumer sciences (FCS) within the ecosystems framework. The purpose of this article is to examine progress of this sub-system within FCS. Specifically, the authors explore the relevance of the systems approach for merchandising programs and conclude that this model is…
Sustainable Design Practices and Consumer Behavior: FCS Student Perceptions

ERIC Educational Resources Information Center

Ulasewicz, Connie; Vouchilas, Gus

2008-01-01

The purpose of this study was to gather information on the perceptions of sustainability in design held by family and consumer sciences (FCS) students majoring in interior design and apparel design/merchandising. Likert-scale responses were used to explore differences and similarities between students in the two majors. Overall, interior design…
"Let's Talk": Collaboration between Family and Consumer Sciences Extension Personnel and Teachers

ERIC Educational Resources Information Center

Abdul-Rahman, Fahzy; Bartley, Sharon Jeffcoat; Cummings, Merrilyn; O'Brien, David

2013-01-01

Interactive meetings between New Mexico Family and Consumer Sciences (FCS) teachers and Extension personnel (county Home Economics agents and state FCS specialists) were conducted to promote collaboration between the two parties. Based on pre- and post-meeting surveys, both parties showed similarities in almost all perceptions and expectations…
Engaging Students: Discovering Family and Consumer Sciences History

ERIC Educational Resources Information Center

Nickols, Sharon Y.; Sewell, Darby; Wilmarth, Melissa

2008-01-01

The centennial of the American Association of Family and Consumer Sciences (AAFCS) provides an opportunity to explore local as well as national aspects of the field. Studying events that shaped FCS and the women and men who provided early leadership reinforces the role of FCS in improving daily living conditions for the past century. Engaging…
Rooted in Mission: Family and Consumer Sciences in Catholic Universities

ERIC Educational Resources Information Center

Duncan, Janine

2011-01-01

The purpose of this paper is to establish the unity between the missions of the Family and Consumer Sciences (FCS) discipline and Catholic higher education by demonstrating relationships among (a) Catholic Social Teaching (CST) and the role of the service principle to FCS; (b) Catholic Intellectual Tradition (CIT) and the centrality of intellect…
Keeping FCS Relevant with Technology

ERIC Educational Resources Information Center

Hays, Annette

2007-01-01

Acorn School campus is located in the shadow of Rich Mountain, near Mena, Arizona. In fall 2006, the school enrollment (K-12) was 476 students, with 76% eligible for free or reduced-cost meals. Its one-teacher family and consumer services (FCS) department offers two programs of study: Family and Consumer Sciences Education and Food Production…

An Examination of the Feasibility of Integrating Motivational Interviewing Techniques into FCS Cooperative Extension Programming

ERIC Educational Resources Information Center

Radunovich, Heidi Liss; Ellis, Sarah; Spangler, Taylor

2017-01-01

Demonstrating program impact through behavior change is critical for the continued success of Family and Consumer Sciences (FCS) Cooperative Extension programming. However, the literature suggests that simply providing information to participants does not necessarily lead to behavior change. This study pilot tested the integration of Motivational…
Family and Consumer Sciences Program Recruitment: An Interdisciplinary Service-Learning Project

ERIC Educational Resources Information Center

Roofe, Nina; Ryburn, Renee

2013-01-01

The family and consumer sciences (FCS) teacher shortage is one need that can be mitigated by exposing high school students to professional trends and future work settings via service-learning. Such exposure can affect student recruitment by influencing high school students' knowledge and attitudes toward FCS careers. This study explored the impact…
FCS Leadership in Financial Health

ERIC Educational Resources Information Center

Delgadillo, Lucy

2014-01-01

This paper presents an idea that will encourage American families and individuals to take charge of their own finances in a holistic manner. A change is proposed in the paradigm that the profession of family and consumer sciences (FCS) has been using to teach family and personal finances in our academic institutions, and a shift is suggested in…
Service Learning in an FCS: A Community-Campus Collaboration

ERIC Educational Resources Information Center

Friesen, Carol A.; Whitaker, Sue H.; Piotrowicz, Kay

2004-01-01

The new core for the Department of Family and Consumer Sciences at Ball State University was designed to provide students with a better understanding of the integrative nature of the family and consumer sciences (FCS) profession. The resultant 9-credit core includes an introductory course, a capstone course, and one student-selected course. The…
University of Idaho's FCS Extension Educators Develop Leaders to Serve in Public Office

ERIC Educational Resources Information Center

Hoffman, Katie; Cummins, Melissa; Hansen, Lyle; Petty, Barbara; Tifft, Kathee; Laumatia, Laura

2013-01-01

In order to meet clientele needs and strengthen family and consumer sciences (FCS) programming, University of Idaho Extension educators expanded their roles through the Horizons program--a community leadership program, funded by the Northwest Area Foundation, aimed at reducing poverty in small rural and reservation communities. This study measured…
Misfit strain-temperature phase diagrams and domain stability of asymmetric ferroelectric capacitors: Thermodynamic calculation and phase-field simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, W. J.; Zheng, Yue, E-mail: zhengy35@mail.sysu.edu.cn; Wu, C. M.

Thermodynamic calculation and phase-field simulation have been conducted to investigate the misfit strain-temperature phase diagrams, dielectric property, and domain stability of asymmetric ferroelectric capacitors (FCs), with considering the effects of dissimilar screening properties and work function steps at the two interfaces. The distinct features of asymmetric FCs from their symmetric counterparts have been revealed and discussed. Polar states with nonzero out-of-plane polarization in parallel with the built-in field are found preferential to form in asymmetric FCs. Meanwhile, the built-in field breaks the degeneracy of states with out-of-plane polarization in anti-directions. This leads to the necessity of redefining phases according tomore » the bistability of out-of-plane polarization. Moreover, the phase stability as well as the dielectric behavior can be significantly controlled by the properties of electrodes, misfit strain, and temperature. The phase-field simulation result also shows that polydomain instability would happen in asymmetric FCs as the equivalence of domain stability in anti-directions is destroyed.« less
Stochastic mechanics of reciprocal diffusions

NASA Astrophysics Data System (ADS)

Levy, Bernard C.; Krener, Arthur J.

1996-02-01

The dynamics and kinematics of reciprocal diffusions were examined in a previous paper [J. Math. Phys. 34, 1846 (1993)], where it was shown that reciprocal diffusions admit a chain of conservation laws, which close after the first two laws for two disjoint subclasses of reciprocal diffusions, the Markov and quantum diffusions. For the case of quantum diffusions, the conservation laws are equivalent to Schrödinger's equation. The Markov diffusions were employed by Schrödinger [Sitzungsber. Preuss. Akad. Wiss. Phys. Math Kl. 144 (1931); Ann. Inst. H. Poincaré 2, 269 (1932)], Nelson [Dynamical Theories of Brownian Motion (Princeton University, Princeton, NJ, 1967); Quantum Fluctuations (Princeton University, Princeton, NJ, 1985)], and other researchers to develop stochastic formulations of quantum mechanics, called stochastic mechanics. We propose here an alternative version of stochastic mechanics based on quantum diffusions. A procedure is presented for constructing the quantum diffusion associated to a given wave function. It is shown that quantum diffusions satisfy the uncertainty principle, and have a locality property, whereby given two dynamically uncoupled but statistically correlated particles, the marginal statistics of each particle depend only on the local fields to which the particle is subjected. However, like Wigner's joint probability distribution for the position and momentum of a particle, the finite joint probability densities of quantum diffusions may take negative values.
What Is a Simple Liquid?

NASA Astrophysics Data System (ADS)

Ingebrigtsen, Trond S.; Schrøder, Thomas B.; Dyre, Jeppe C.

2012-01-01

This paper is an attempt to identify the real essence of simplicity of liquids in John Locke’s understanding of the term. Simple liquids are traditionally defined as many-body systems of classical particles interacting via radially symmetric pair potentials. We suggest that a simple liquid should be defined instead by the property of having strong correlations between virial and potential-energy equilibrium fluctuations in the NVT ensemble. There is considerable overlap between the two definitions, but also some notable differences. For instance, in the new definition simplicity is not a direct property of the intermolecular potential because a liquid is usually only strongly correlating in part of its phase diagram. Moreover, not all simple liquids are atomic (i.e., with radially symmetric pair potentials) and not all atomic liquids are simple. The main part of the paper motivates the new definition of liquid simplicity by presenting evidence that a liquid is strongly correlating if and only if its intermolecular interactions may be ignored beyond the first coordination shell (FCS). This is demonstrated by NVT simulations of the structure and dynamics of several atomic and three molecular model liquids with a shifted-forces cutoff placed at the first minimum of the radial distribution function. The liquids studied are inverse power-law systems (r-n pair potentials with n=18,6,4), Lennard-Jones (LJ) models (the standard LJ model, two generalized Kob-Andersen binary LJ mixtures, and the Wahnstrom binary LJ mixture), the Buckingham model, the Dzugutov model, the LJ Gaussian model, the Gaussian core model, the Hansen-McDonald molten salt model, the Lewis-Wahnstrom ortho-terphenyl model, the asymmetric dumbbell model, and the single-point charge water model. The final part of the paper summarizes properties of strongly correlating liquids, emphasizing that these are simpler than liquids in general. Simple liquids, as defined here, may be characterized in three quite different ways: (1) chemically by the fact that the liquid’s properties are fully determined by interactions from the molecules within the FCS, (2) physically by the fact that there are isomorphs in the phase diagram, i.e., curves along which several properties like excess entropy, structure, and dynamics, are invariant in reduced units, and (3) mathematically by the fact that throughout the phase diagram the reduced-coordinate constant-potential-energy hypersurfaces define a one-parameter family of compact Riemannian manifolds. No proof is given that the chemical characterization follows from the strong correlation property, but we show that this FCS characterization is consistent with the existence of isomorphs in strongly correlating liquids’ phase diagram. Finally, we note that the FCS characterization of simple liquids calls into question the physical basis of standard perturbation theory, according to which the repulsive and attractive forces play fundamentally different roles for the physics of liquids.
Animal serum-free culture conditions for isolation and expansion of multipotent mesenchymal stromal cells from human BM.

PubMed

Müller, I; Kordowich, S; Holzwarth, C; Spano, C; Isensee, G; Staiber, A; Viebahn, S; Gieseke, F; Langer, H; Gawaz, M P; Horwitz, E M; Conte, P; Handgretinger, R; Dominici, M

2006-01-01

Multipotent mesenchymal stromal cells (MSC) have become important tools in regenerative and transplantation medicine. Rapidly increasing numbers of patients are receiving in vitro-expanded MSC. Culture conditions typically include FSC because human serum does not fully support growth of human MSC in vitro (MSC(FCS)). Concerns regarding BSE, other infectious complications and host immune reactions have fueled investigation of alternative culture supplements. As PDGF has long been identified as a growth factor for MSC, we tested media supplementation with platelet lysate for support of MSC proliferation. We found that primary cultures of BM-derived MSC can be established with animal serum-free media containing fresh frozen plasma and platelets (MSC(FFPP)). Moreover, MSC(FFPP) showed vigorous proliferation that was superior to classical culture conditions containing FCS. MSC(FFPP) morphology was equivalent to MSC(FCS), and MSC(FFPP) expressed CD73, CD90, CD105, CD106, CD146 and HLA-ABC while being negative for CD34, CD45 and surface HLA-DR, as expected. In addition to being phenotypically identical, MSC(FFPP) could efficiently differentiate into adipocytes and osteoblasts. In terms of immune regulatory properties, MSC(FFPP) were indistinguishable from MSC(FCS). Proliferation of PBMC induced by IL-2 in combination with OKT-3 or by PHA was inhibited in the presence of MSC(FFPP). Taken together, FCS can be replaced safely by FFPP in cultures of MSC for clinical purposes.
Optimized human platelet lysate as novel basis for a serum-, xeno-, and additive-free corneal endothelial cell and tissue culture.

PubMed

Thieme, Daniel; Reuland, Lynn; Lindl, Toni; Kruse, Friedrich; Fuchsluger, Thomas

2018-02-01

The expansion of donor-derived corneal endothelial cells (ECs) is a promising approach for regenerative therapies in corneal diseases. To achieve the best Good Manufacturing Practice standard the entire cultivation process should be devoid of nonhuman components. However, so far, there is no suitable xeno-free protocol for clinical applications. We therefore introduce a processed variant of a platelet lysate for the use in corneal cell and tissue culture based on a Good Manufacturing Practice-grade thrombocyte concentrate. This processed human platelet lysate (phPL), free of any animal components and of anticoagulants such as heparin with a physiological ionic composition, was used to cultivate corneal ECs in vitro and ex vivo in comparison to standard cultivation with fetal calf serum (FCS). Human donor corneas were cut in quarters while 2 quarters of each cornea were incubated with the respective medium supplement. Three fields of view per quarter were taken into account for the analysis. Evaluation of phPL as a medium supplement in cell culture of immortalized EC showed a superior viability compared with FCS control with reduced cell proliferation. Furthermore, the viability during the expansion of primary cells is significantly (3-fold ±0.5) increased with phPL compared with FCS standard medium. Quartering donor corneas was traumatic for the endothelium and therefore resulted in increased EC loss. Interestingly, however, cultivation of the quartered pieces for 2 weeks in 0.1-mg/ml pHPL in Biochrome I showed a 21 (±10) % EC loss compared with 67 (±12) % EC loss when cultivated in 2% FCS in Biochrome I. The cell culture protocol with pHPL as FCS replacement seems to be superior to the standard FCS protocols with respect to EC survival. It offers a xeno-free and physiological environment for corneal endothelial cells. This alternative cultivation protocol could facilitate the use of EC for human corneal cell therapy. Copyright © 2017 John Wiley & Sons, Ltd.
Differing strategies of patterning of follicular cells in higher and lower brachycerans (Diptera: Brachycera).

PubMed

Tworzydlo, Waclaw; Jablonska, Anna; Kisiel, Elzbieta; Bilinski, Szczepan M

2005-10-01

In all higher dipterans (Brachycera), including the fruitfly, Drosophila melanogaster, each egg chamber (ovarian follicle) consists of a group (clone) of germ cells (one oocyte and 15 accompanying nurse cells) that is surrounded by a layer of somatic mesodermal follicular cells (FCs). As oogenesis progresses the initially uniform FCs diversify into several morphologically and functionally distinct subpopulations. In D. melanogaster some of these subpopulations, e.g., border, centripetal, and dorsolateral cells, undertake coordinated migration or rearrangement over the surface of the germ cells. During the final stages of oogenesis these subpopulations participate in the formation of a complex, regionally specialized eggshell. In representatives of lower brachycerans (Orthorrhapha), only FCs that undertake active, directed migration are the border cells. These cells originate at the anterior pole of the ovarian follicle and migrate between the nurse cells to the anterior pole of the oocyte. Reduced motility of FCs in lower brachycerans results in the absence of certain FC subpopulations in their egg chambers and subsequent simplicity of their eggshells. We found that the lack of some FC subpopulations coincided with the appearance of lamellipodium-like protrusions of the oocyte. These protrusions penetrated between the apposing membranes of nurse and FCs and partially enveloped the nurse cell compartment. Analysis of whole-mount preparations stained with rhodamine-conjugated phalloidin revealed that the protrusions contained microfilaments and that their tips were equipped with actin-rich filopodium-like processes. We also found that in some lower brachycerans (representatives of the family Rhagionidae), the FCs located at the posterior pole of the oocyte, became enlarged and morphologically similar to the anterior border cells. These findings indicate that in higher dipterans the processes leading to the formation of a functional egg are variable and often markedly different from those in the model organism, D. melanogaster. genesis 43:49-58, 2005. (c) 2005 Wiley-Liss, Inc.
Favorite Demonstrations: Gaseous Diffusion: A Demonstration of Graham's Law.

ERIC Educational Resources Information Center

Kauffman, George B.; Ebner, Ronald D.

1985-01-01

Describes a demonstration in which gaseous ammonia and hydrochloric acid are used to illustrate rates of diffusion (Graham's Law). Simple equipment needed for the demonstration include a long tube, rubber stoppes, and cotton. Two related demonstrations are also explained. (DH)
Intrinsic Functional Connectivity Patterns Predict Consciousness Level and Recovery Outcome in Acquired Brain Injury

PubMed Central

Wu, Xuehai; Zou, Qihong; Hu, Jin; Tang, Weijun; Mao, Ying; Gao, Liang; Zhu, Jianhong; Jin, Yi; Wu, Xin; Lu, Lu; Zhang, Yaojun; Zhang, Yao; Dai, Zhengjia; Gao, Jia-Hong; Weng, Xuchu; Northoff, Georg; Giacino, Joseph T.; He, Yong

2015-01-01

For accurate diagnosis and prognostic prediction of acquired brain injury (ABI), it is crucial to understand the neurobiological mechanisms underlying loss of consciousness. However, there is no consensus on which regions and networks act as biomarkers for consciousness level and recovery outcome in ABI. Using resting-state fMRI, we assessed intrinsic functional connectivity strength (FCS) of whole-brain networks in a large sample of 99 ABI patients with varying degrees of consciousness loss (including fully preserved consciousness state, minimally conscious state, unresponsive wakefulness syndrome/vegetative state, and coma) and 34 healthy control subjects. Consciousness level was evaluated using the Glasgow Coma Scale and Coma Recovery Scale-Revised on the day of fMRI scanning; recovery outcome was assessed using the Glasgow Outcome Scale 3 months after the fMRI scanning. One-way ANOVA of FCS, Spearman correlation analyses between FCS and the consciousness level and recovery outcome, and FCS-based multivariate pattern analysis were performed. We found decreased FCS with loss of consciousness primarily distributed in the posterior cingulate cortex/precuneus (PCC/PCU), medial prefrontal cortex, and lateral parietal cortex. The FCS values of these regions were significantly correlated with consciousness level and recovery outcome. Multivariate support vector machine discrimination analysis revealed that the FCS patterns predicted whether patients with unresponsive wakefulness syndrome/vegetative state and coma would regain consciousness with an accuracy of 81.25%, and the most discriminative region was the PCC/PCU. These findings suggest that intrinsic functional connectivity patterns of the human posteromedial cortex could serve as a potential indicator for consciousness level and recovery outcome in individuals with ABI. SIGNIFICANCE STATEMENT Varying degrees of consciousness loss and recovery are commonly observed in acquired brain injury patients, yet the underlying neurobiological mechanisms remain elusive. Using a large sample of patients with varying degrees of consciousness loss, we demonstrate that intrinsic functional connectivity strength in many brain regions, especially in the posterior cingulate cortex and precuneus, significantly correlated with consciousness level and recovery outcome. We further demonstrate that the functional connectivity pattern of these regions can predict patients with unresponsive wakefulness syndrome/vegetative state and coma would regain consciousness with an accuracy of 81.25%. Our study thus provides potentially important biomarkers of acquired brain injury in clinical diagnosis, prediction of recovery outcome, and decision making for treatment strategies for patients with severe loss of consciousness. PMID:26377477
The diffusion and impact of clean indoor air laws.

PubMed

Eriksen, Michael P; Cerak, Rebecca L

2008-01-01

Over the past quarter century, primarily as a result of scientific discovery, citizen advocacy, and legislative action, comprehensive clean indoor air laws have spread rapidly throughout the world. Laws that establish completely smoke-free indoor environments have many relative advantages including being low cost, safe, effective, and easy to implement. The diffusion of these laws has been associated with a dramatic and rapid reduction in population levels of serum cotinine among nonsmokers and has also contributed to a reduction in overall cigarette consumption among smokers, with no adverse economic impact, except to the tobacco industry. Currently, nearly half of the U.S. population lives in jurisdictions with some combination of completely smoke-free workplaces, restaurants, or bars. The diffusion of clean indoor air laws is spreading rapidly throughout the world, stimulated by the first global health treaty, the Framework Convention on Tobacco Control.
The FCS Body of Knowledge: Shaping the Next 100 Years

ERIC Educational Resources Information Center

Journal of Family and Consumer Sciences, 2010

2010-01-01

This article shares the Body of Knowledge (BOK) as articulated in the new "Accreditation Documents for Undergraduate Programs in Family and Consumer Sciences" (2010). The purpose of sharing the BOK is to enhance awareness of the current knowledge base of family and consumer sciences (FCS), whether for new or lifelong AAFCS members, those exploring…
Administrator and Faculty Perceptions of Institutional Support for Online Education in Florida's College System

ERIC Educational Resources Information Center

Thompson, Gerene M.

2017-01-01

Approximately 30% of Florida's college system (FCS) students are enrolled in distance learning courses (FLDOE, 2015). As FCS institutions continue to grow their online programs to meet demand, a lack of support from, and consensus among administrator and faculty stakeholders could undermine institutional efforts to sustain growth and quality…
California Community College Family and Consumer Sciences in the 21st Century.

ERIC Educational Resources Information Center

California Community Colleges, Sacramento. Office of the Chancellor.

Prepared as a companion to a 1996 California Community College plan for family and consumer sciences (FCS), this resource packet provides materials to help faculty, administrators, counselors, and other educators understand the elements of the plan, sharpen their focus on the dynamics of FCS programs, and increase support for programs at their…
An Action Plan for FCS. Putting the Family Perspective into Healthcare

ERIC Educational Resources Information Center

Riportella, Roberta

2005-01-01

Family and consumer sciences (FCS) professionals often are called upon to work with groups that are seeking to create healthier communities. This article offers an expanded perspective on what it means to include a family focus in these discussions and it answers the question, How does a family perspective lead to different solutions for creating…
A Study in Iowa. Teaching Food Safety in Secondary FCS Classes

ERIC Educational Resources Information Center

Ellis, Jason D.; Henroid, Daniel H., Jr.

2005-01-01

Food safety is a significant issue in the United States and yet minimal research has been done on the inclusion of food safety in secondary school curricula. This study examined the feasibility of including food safety in Iowa FCS middle and secondary classes. Teachers reported food safety was important; only a few believed students were…
The Mode of Professional Teaching Practice of FCS Teacher-Leaders and Non-Teacher-Leaders.

ERIC Educational Resources Information Center

Fox, Candace K.; Laster, Janet F.

A study was conducted to determine which of the following modes of professional practice is the dominant mode used by Ohio family and consumer science (FCS) teachers when implementing a refined critical science based curriculum: technical-rational; reflective-ethical; and process-oriented. The target population consisted of 1,013 secondary…

The Manifesto for Extension and Engagement: A Perspective on Family and Consumer Sciences for the Future

ERIC Educational Resources Information Center

Carroll, Jan B.; Chamberlin, Barbara; Devall, Esther; Dinstel, Roxie; Hauser-Lindstrom, Doreen; Petty, Barbara D.

2017-01-01

Extension professionals in the Western Region proclaimed The Timberline Manifesto at their 100-year celebration, "Centennial on the Summit," at Mount Hood, OR, in 2014. Family and consumer sciences (FCS) leaders relate this platform to the future of FCS: our opportunities for success in engagement, integration, technology, demand-driven…
Factorial Invariance of the Asian American Family Conflicts Scale across Ethnicity, Generational Status, Sex, and Nationality

ERIC Educational Resources Information Center

Miller, Matthew J.; Lee, Richard M.

2009-01-01

The factorial invariance of the Asian American Family Conflicts Scale-Likelihood (FCS-L) was examined in a sample of 1,012 participants. Results support the use of the FCS-L in future research with diverse Asian subgroups. Limitations and future directions for research are discussed. (Contains 7 tables and 1 note.)
Instructional Environments and Learning: Exploring Knowledge Growth in Preservice Family and Consumer Sciences Education.

ERIC Educational Resources Information Center

Jensen, Jacquelyn W.; Rowley, Maxine L.

This study examined what 16 female family and consumer sciences (FCS) preservice teachers learned given 1 instructional environment. Participants were enrolled in three FCS teaching methods and curriculum courses. A 2-hour lesson on classroom management using small group theory was selected. On the first day of class, participants completed…
76 FR 80817 - Funding and Fiscal Affairs, Loan Policies and Operations, and Funding Operations; Liquidity and...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-27

... liquidity regulation. The purpose of the proposed rule is to strengthen liquidity risk management at Farm...; Strengthen liquidity management at all FCS banks; Enhance the marketability of assets that System banks hold... various provisions of the Act to supervise and regulate liquidity management at FCS banks. Section 5.17(a...
Scaffolding Mathematics Remediation for Academically At-Risk Students Following Developmental Education Reform in Florida

ERIC Educational Resources Information Center

Rebecca, Brower L.; Woods, Chenoa S.; Bertrand Jones, Tamara; Park, Toby J.; Hu, Shouping; Tandberg, David A.; Nix, Amanda; Rhaming, Sophia G.; Martindale, Sandra K.

2017-01-01

The purpose of this qualitative study is to understand how educational scaffolding may explain changing patterns of student success in mathematics in the era of developmental education (DE or remediation) reform in Florida College System (FCS) institutions. Specifically, we apply the concept of scaffolding to underprepared FCS students who are at…
Scaffolding Mathematics Remediation for Academically At-Risk Students Following Developmental Education Reform in Florida

ERIC Educational Resources Information Center

Brower, Rebecca L.; Woods, Chenoa S.; Jones, Tamara Bertrand; Park, Toby J.; Hu, Shouping; Tandberg, David A.; Nix, Amanda N.; Rahming, Sophia G.; Martindale, Sandra K.

2018-01-01

The purpose of this qualitative study is to understand how educational scaffolding may explain changing patterns of student success in mathematics in the era of developmental education (DE or remediation) reform in Florida College System (FCS) institutions. Specifically, we apply the concept of scaffolding to underprepared FCS students who are at…
Nutrition Instruction in Seventh Grade: A Comparison of Teachers with and without FCS Background

ERIC Educational Resources Information Center

Murimi, Mary W.; Sample, Alicia; Hunt, Alice

2008-01-01

This study compared attitudes and confidence levels, regarding classroom nutrition education, of seventh grade teachers of nutrition, family and consumer sciences (FCS), or health education. A 17-item online questionnaire was used to obtain the data from randomly selected schools in Louisiana. Teachers who reported an educational background in FCS…
Key Concepts of Environmental Sustainability: Knowledge and Confidence Levels of FCS Teachers

ERIC Educational Resources Information Center

Harden, Amy J.; Friesen, Carol A.; Thompson, Nancy E.

2014-01-01

Family and consumer sciences (FCS) is a logical discipline to promote environmental sustainability within the family because it is recognized as helping people make informed decisions about the well-being of individuals and their relationships and resources to achieve optimal quality of life.The objective of this article was to measure the…
In-Flight Suppression of a De-Stabilized F/A-18 Structural Mode Using the Space Launch System Adaptive Augmenting Control System

NASA Technical Reports Server (NTRS)

Wall, John; VanZwieten, Tannen; Giiligan Eric; Miller, Chris; Hanson, Curtis; Orr, Jeb

2015-01-01

Adaptive Augmenting Control (AAC) has been developed for NASA's Space Launch System (SLS) family of launch vehicles and implemented as a baseline part of its flight control system (FCS). To raise the technical readiness level of the SLS AAC algorithm, the Launch Vehicle Adaptive Control (LVAC) flight test program was conducted in which the SLS FCS prototype software was employed to control the pitch axis of Dryden's specially outfitted F/A-18, the Full Scale Advanced Systems Test Bed (FAST). This presentation focuses on a set of special test cases which demonstrate the successful mitigation of the unstable coupling of an F/A-18 airframe structural mode with the SLS FCS.
Nitric oxide treatment reduces neo-intimal formation and modulates osteopontin expression in an ex-vivo human model of intimal hyperplasia.

PubMed

Colotti, Chiara; Vittorini, Simona; Ottaviano, Virginia; Maltinti, Maristella; Angeli, Valeria; Del Ry, Silvia; Giannessi, Daniela

2009-05-01

In this study the effects of nitric oxide (NO) on intimal hyperplasia (IH) were evaluated in an ex-vivo model of human saphenous vein (SV). SV segments were cultured in conditions able to reproduce IH (FCS), or in medium alone (RPMI), or in presence of a NO donor (NO). Osteopontin (OPN) and Interleukin (IL)-6 were determined in the medium at different culture times and in the tissue, at the end of experiment. OPN and IL-6 release in medium was increased in FCS with respect to RPMI (OPN: 13.9+/-2.9 vs. 2.3+/-0.8 microg/ml, p=0.0011; IL-6: 304.2+/-64.7 vs. 42.0+/-10.1 ng/ml, p<0.0006) as well as intima thickness, that positively correlated with OPN production (r=0.81). In tissue OPN was higher in FCS (82.0+/-30.3 ng/mg protein) than in RPMI (13.8+/-4.2, p=0.0051) and at baseline (3.7+/-0.7, p=0.018). NO reduces IH progression (25%) and both OPN and IL-6 expression (OPN/GAPDH: undetectable baseline; 0.27+/-0.06 RPMI; 0.89+/-0.28 FCS; 0.09+/-0.05 NO; p=0.026 FCS vs. baseline, p=0.018 vs. RPMI, p=0.005 vs. NO). The beneficial NO effect on IH reduction appears to be mediated by the indirect inhibition of OPN production. NO could modulates the initial inflammatory signals that induces the OPN over-production with the related cascade of events leading to IH.
[The use of immunohistochemistry in the differential diagnosis of thyroid gland tumors with follicular growth pattern].

PubMed

Laco, J; Ryska, A

2006-07-01

The aim of the study was to evaluate the expression of galectin-3 (gal3), cytokeratin 19 (CK19), neural cell adhesion molecule (NCAM), and E-cadherin (Ecad) in thyroid gland tumors with follicular growth pattern with particular focus on their use in differential diagnosis. A series of 139 cases - 87 follicular adenomas (FAs), 26 follicular carcinomas (FCs), and 26 cases of the follicular variant of papillary carcinoma (FVPC) was studied. Expression of gal3 was found in 29/87 (33%) of FAs, in 13/26 (50%) of FCs, and in 24/26 (92%) of FVPCs. Expression of CK19 was found in 11/87 (13%) of FAs, in 4/26 (15%) of FCs, and in 17/26 (65%) of FVPCs. Expression of NCAM was found in 60/87 (69%) of FAs, in 20/26 (77%) of FCs, and in 7/26 (27%) FVPCs. Expression of Ecad was found in 81/87 (93%) of FAs, in 22/26 (85%) of FCs, and in 17/26 (65%) of FVPCs. The sensitivity and specificity of gal3 for malignancy were 0.70 and 0.85, of CK19 0.48 and 0.98, of NCAM 0.28 and 0.47, and of Ecad 0.48 and 0.20, respectively. A significant difference (p < 0.05) in expression of all studied markers between FVPC versus FA and FC was found, in contrast to FA and FC. Therefore, the use of gal3 and CK19 in differential diagnosis of FVPC versus FA and FC can be recommended.
Test-retest reliability at the item level and total score level of the Norwegian version of the Spinal Cord Injury Falls Concern Scale (SCI-FCS).

PubMed

Roaldsen, Kirsti Skavberg; Måøy, Åsa Blad; Jørgensen, Vivien; Stanghelle, Johan Kvalvik

2016-05-01

Translation of the Spinal Cord Injury Falls Concern Scale (SCI-FCS), and investigation of test-retest reliability on item-level and total-score-level. Translation, adaptation and test-retest study. A specialized rehabilitation setting in Norway. Fifty-four wheelchair users with a spinal cord injury. The median age of the cohort was 49 years, and the median number of years after injury was 13. Interventions/measurements: The SCI-FCS was translated and back-translated according to guidelines. Individuals answered the SCI-FCS twice over the course of one week. We investigated item-level test-retest reliability using Svensson's rank-based statistical method for disagreement analysis of paired ordinal data. For relative reliability, we analyzed the total-score-level test-retest reliability with intraclass correlation coefficients (ICC2.1), the standard error of measurement (SEM), and the smallest detectable change (SDC) for absolute reliability/measurement-error assessment and Cronbach's alpha for internal consistency. All items showed satisfactory percentage agreement (≥69%) between test and retest. There were small but non-negligible systematic disagreements among three items; we recovered an 11-13% higher chance for a lower second score. There was no disagreement due to random variance. The test-retest agreement (ICC2.1) was excellent (0.83). The SEM was 2.6 (12%), and the SDC was 7.1 (32%). The Cronbach's alpha was high (0.88). The Norwegian SCI-FCS is highly reliable for wheelchair users with chronic spinal cord injuries.
Structure and biological activity of a fucosylated chondroitin sulfate from the sea cucumber Cucumaria japonica.

PubMed

Ustyuzhanina, Nadezhda E; Bilan, Maria I; Dmitrenok, Andrey S; Shashkov, Alexander S; Kusaykin, Mikhail I; Stonik, Valentin A; Nifantiev, Nikolay E; Usov, Anatolii I

2016-05-01

A fucosylated chondroitin sulfate (FCS) was isolated from the body wall of Pacific sea cucumber Cucumaria japonicaby extraction in the presence of papain followed by Cetavlon precipitation and anion-exchange chromatography. FCS was shown to contain D-GalNAc, D-GlcA, L-Fuc and sulfate in molar proportions of about 1:1:1:4.5. Structure of FCS was elucidated using NMR spectroscopy and methylation analysis of the native polysaccharide and products of its desulfation and carboxyl reduction. The polysaccharide was shown to contain a typical chondroitin core → 3)-β-D-GalNAc-(1 → 4)-β-D-GlcA-(1 →. Sulfate groups in this core occupy O-4 and the majority of O-6 of GalNAc. Fucosyl branches are represented by 3,4- and 2,4-disulfated units in a ratio of 4:1 and are linked to O-3 of GlcA. In addition, ∼ 33% of GlcA are 3-O-sulfated, and hence, the presence of short fucooligosaccharide chains side by side with monofucosyl branches cannot be excluded. FCS was shown to inhibit platelets aggregation in vitro mediated by collagen and ristocetin, but not adenosine diphosphate, and demonstrated significant anticoagulant activity, which is connected with its ability to enhance inhibition of thrombin and factor Xa by antithrombin III, as well as to influence von Willebrand factor activity. The latest property significantly distinguished FCS from low-molecular-weight heparin. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Enhancing the sensitivity of fluorescence correlation spectroscopy by using time-correlated single photon counting.

PubMed

Lamb, D C; Müller, B K; Bräuchle, C

2005-10-01

Fluorescence correlation spectroscopy (FCS) and fluorescence cross-correlation spectroscopy (FCCS) are methods that extract information about a sample from the influence of thermodynamic equilibrium fluctuations on the fluorescence intensity. This method allows dynamic information to be obtained from steady state equilibrium measurements and its popularity has dramatically increased in the last 10 years due to the development of high sensitivity detectors and its combination with confocal microscopy. Using time-correlated single-photon counting (TCSPC) detection and pulsed excitation, information over the duration of the excited state can be extracted and incorporated in the analysis. In this short review, we discuss new methodologies that have recently emerged which incorporated fluorescence lifetime information or TCSPC data in the FCS and FCCS analysis. Time-gated FCS discriminates between which photons are to be incorporated in the analysis dependent upon their arrival time after excitation. This allows for accurate FCS measurements in the presence of fluorescent background, determination of sample homogeneity, and the ability to distinguish between static and dynamic heterogeneities. A similar method, time-resolved FCS can be used to resolve the individual correlation functions from multiple fluorophores through the different fluorescence lifetimes. Pulsed interleaved excitation (PIE) encodes the excitation source into the TCSPC data. PIE can be used to perform dual-channel FCCS with a single detector and allows elimination of spectral cross-talk with dual-channel detection. For samples that undergo fluorescence resonance energy transfer (FRET), quantitative FCCS measurements can be performed in spite of the FRET and the static FRET efficiency can be determined.
Biological Features of Human Bone Marrow Stromal Cells (hBMSC) Cultured with Animal Protein-Free Medium-Safety and Efficacy of Clinical Use for Neurotransplantation.

PubMed

Shichinohe, Hideo; Kuroda, Satoshi; Sugiyama, Taku; Ito, Masaki; Kawabori, Masahito; Nishio, Mitsufumi; Takeda, Yukari; Koike, Takao; Houkin, Kiyohiro

2011-09-01

The donor cell culture in animal serum-free medium is quite important for the clinical application of cell transplantation therapy. This study was aimed to test the hypothesis that the human bone marrow stromal cells (hBMSC) expanded with fetal calf serum (FCS)-free, platelet lysate (PL)-containing medium retain their biological features favoring central nervous system regeneration. The hBMSC were cultured with 5% PL or 10% FCS. Their phenotypes were analyzed with flow cytometry, and their production of growth factors was quantified with enzyme-linked immunosorbent assay. Their capacity of neural differentiation was verified by immunocytochemistry. There was no significant difference in morphology and cell surface marker between the hBMSC-FCS and hBMSC-PL. Both of them were positive for CD44, CD90, CD105, and CD166 and were negative for CD34, CD45, and CD271. The production of human brain-derived neurotrophic factor, human hepatocyte growth factor, human β-nerve growth factor, and human platelet-derived growth factor-BB did not differ between the two groups, although the hBMSC-PL produced significantly more amount of TGF-β1 than the hBMSC-FCS. There was no significant difference in their in vitro differentiation into the neurons and astrocytes between the two groups. The hBMSC expanded with PL-containing medium retain their biological capacity of neural differentiation and neuroprotection. The PL may be a clinically valuable and safe substitute for FCS in expanding the hBMSC for cell therapy.
Magnitude of faecal contamination of rural community well waters in Nigeria and its relationship to well and water properties.

PubMed

Ogan, M T

1989-12-01

The possible relationship between high numbers of fecal coliforms (FCs), fecal streptococci (FS), standard plate count (SPCs) and well characteristics viz: well depth, water column, temperature, pH and non-filterable residue in 25 rural community wells in the Port Harcourt region, Nigeria, was studied. Zonal differences in residue level, well depth and fecal indicator bacteria were observed; these parameters were lowest in an area of high population density (slum) reclaimed from and adjacent to mangrove forests. Although some wells were covered and/or walled to protect them from surface runoff contamination, FCs and FS were recovered from all, except three, in numbers (log10 per 100 mL) ranging respectively from 0.40-3.79 and 0.70-3.44. The FC:FS ratio was less than 1.0 in 8 and greater than 1.0 in 14 samples. Well depth correlated with FCs (p = 0.01; r = 0.5684), FS (p = 0.001; r = 0.6423), pH (p = 0.0001; r = 0.5981); FCs and FS correlated significantly (p = 0.01; r = 0.4948). SPCs did not correlate significantly with FCs, FS and the well and water characteristics. Simultaneous analysis of samples by the Membrane-filtration (MF) and Most Probable Number (MPN) methods recovered mean FC counts in the decreasing sequence: Standard-MPN----Anaerobic----Aerobic MF----Direct-MPN. The underground water table is most probably contaminated via large numbers of soakaway pits and similar conveniences. Downward movement of contaminant from the shallow conveniences into deeper water tables may explain the well depth: indicator bacteria correlation.
Leadership in Mobile Technology: An Opportunity for Family and Consumer Sciences Teacher Educators

ERIC Educational Resources Information Center

Godfrey, Roxie V.; Duke, Sandra E.

2014-01-01

A stroll across campus reveals that students are plugged into mobile technology. They never have to break stride in their social connectivity as they pursue an education.Where does the family and consumer sciences (FCS) teacher educator fit into this opportunistic scenario? From its inception, FCS has been at the forefront in the application of…
Fungal lactone ring opening of 6', 7'-dihydroxybergamottin diminishes cytochrome P450 3A4 inhibitory activity

USDA-ARS?s Scientific Manuscript database

Furanocoumarins (FCs) are a class of aromatic compounds in grapefruit that inhibit human intestinal cytochrome P450 3A4 (CYP3A4). Since fungi metabolize polycyclic aromatic hydrocarbons, we hypothesized that certain fungi might also metabolize FCs into forms that may be inactive as CYP3A4 inhibitors...
Does magnetic storm generation depend on the solar wind type?

NASA Astrophysics Data System (ADS)

Nikolaeva, N. S.; Yermolaev, Yu. I.; Lodkina, I. G.; Yermolaev, M. Yu.

2017-09-01

The purpose of this work is to draw the reader's attention to the problem of possible differences in the generation of magnetic storms by different large-scale solar wind types: corotating interaction regions (CIRs), Sheaths, and interplanetary coronal mass ejections (ICMEs), including magnetic clouds (MCs) and Ejecta. We recently showed that the description of relationships between interplanetary conditions and Dst and Dst* indices with the modified formula by Burton et al. gives an 50% higher efficiency of storm generation by Sheath and CIR than that by ICME. Many function couplings (FCs) between different interplanetary parameters and the magnetosphere state have been suggested in the literature; however, they have not been analyzed for different solar wind types. In this work, we study the generation efficiency of the main phase of a storm by different solar wind streams with the use of 12 FCs on the basis of OMNI data for 1976-2000. The results show that the Sheath has the highest efficiency for most FCs, and MC is the least efficient, and this result corresponds to our previous results. The reliability of the results and possible causes of differences for different FCs and solar wind types are to be studied further.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Bulut, Y.; Karayigit, A.I.

The coal-bearing Soma basin is one of the most productive lacustrine coal basins of western Anatolia-Turkey. This study mainly focuses on petrography of the feed coals (FCs) in the Soma power plant. A total of 16 feed coal samples were systematically collected once a week over an eight-week period from both group boiler units, B1-4 with 660 MW and B5-6 with 330 MW capacity. The most abundant maceral group of FCs is huminite, in which texto-ulminite, eu-ulminite, attrinite, densinite are rich. Liptinite group macerals in FCs include mainly sporinite, resinite, and liptodetrinite, which are considerably higher than the other identifiedmore » liptinite macerals. In the inertinite group, fusinite and inertodetrinite are more abundant. Identifiable minerals with petrographical studies are pyrite, siderite, other minerals (e. g., carbonates, clay minerals, quartz, feldspar, etc.), and fossil shells. This study shows that FCs used are subbituminous in rank with mean random ulminite reflectance of 0.43% Rr oil from B1-4 units and 0.39% Rr oil from B5-6 units. This indicates that coal rank is slightly higher in the central mines (southern Soma) than in the Denis mines (northern Soma).« less

Development of novel microsatellite markers for Holothurian scabra (Holothuriidae), Apostichopus japonicas (Stichopodidae) and cross-species testing in other sea cucumbers

NASA Astrophysics Data System (ADS)

Shangguan, Jingbo; Li, Zhongbao

2017-06-01

Thirty-five new microsatellite loci from the sea cucumbers Holothurian scabra (Jaeger, 1833) and Apostichopus japonicas (Selenka, 1867) were screened and characterized using the method of magnetic bead enrichment. Of the twenty-four polymorphic loci tested, eighteen were consistent with Hardy-Weinberg equilibrium after a modified false discovery rate (B-Y FDR) correction, whereas six showed statistically significant deviations (CHS2 and CHS11: P <0.014790; FCS1, FCS6, FCS8 and FCS14: P <0.015377). Furthermore, four species of plesiomorphous and related sea cucumbers (Holothurian scabra, Holothuria leucospilota, Stichopus horrens and Apostichopus japonicas) were tested for mutual cross-amplification using a total of ninety microsatellite loci. Although transferability and universality of all loci were generally low, the results of the cross-species study showed that the markers can be applied to identify individuals to species according to the presence or absence of specific microsatellite alleles. The microsatellite markers reported here will contribute to the study of genetic diversity, assisted breeding, and population conservation in sea cucumbers, as well as allow for the identification of individuals to closely related species.
Development of novel microsatellite markers for Holothurian scabra (Holothuriidae), Apostichopus japonicas (Stichopodidae) and cross-species testing in other sea cucumbers

NASA Astrophysics Data System (ADS)

Shangguan, Jingbo; Li, Zhongbao

2018-03-01

Thirty-five new microsatellite loci from the sea cucumbers Holothurian scabra (Jaeger, 1833) and Apostichopus japonicas (Selenka, 1867) were screened and characterized using the method of magnetic bead enrichment. Of the twenty-four polymorphic loci tested, eighteen were consistent with Hardy-Weinberg equilibrium after a modified false discovery rate (B-Y FDR) correction, whereas six showed statistically significant deviations (CHS2 and CHS11: P<0.014 790; FCS1, FCS6, FCS8 and FCS14: P<0.015 377). Furthermore, four species of plesiomorphous and related sea cucumbers ( Holothurian scabra, Holothuria leucospilota, Stichopus horrens and Apostichopus japonicas) were tested for mutual cross-amplification using a total of ninety microsatellite loci. Although transferability and universality of all loci were generally low, the results of the cross-species study showed that the markers can be applied to identify individuals to species according to the presence or absence of specific microsatellite alleles. The microsatellite markers reported here will contribute to the study of genetic diversity, assisted breeding, and population conservation in sea cucumbers, as well as allow for the identification of individuals to closely related species.
Diffusion Processes Satisfying a Conservation Law Constraint

DOE PAGES

Bakosi, J.; Ristorcelli, J. R.

2014-03-04

We investigate coupled stochastic differential equations governing N non-negative continuous random variables that satisfy a conservation principle. In various fields a conservation law requires that a set of fluctuating variables be non-negative and (if appropriately normalized) sum to one. As a result, any stochastic differential equation model to be realizable must not produce events outside of the allowed sample space. We develop a set of constraints on the drift and diffusion terms of such stochastic models to ensure that both the non-negativity and the unit-sum conservation law constraint are satisfied as the variables evolve in time. We investigate the consequencesmore » of the developed constraints on the Fokker-Planck equation, the associated system of stochastic differential equations, and the evolution equations of the first four moments of the probability density function. We show that random variables, satisfying a conservation law constraint, represented by stochastic diffusion processes, must have diffusion terms that are coupled and nonlinear. The set of constraints developed enables the development of statistical representations of fluctuating variables satisfying a conservation law. We exemplify the results with the bivariate beta process and the multivariate Wright-Fisher, Dirichlet, and Lochner’s generalized Dirichlet processes.« less
Diffusion Processes Satisfying a Conservation Law Constraint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bakosi, J.; Ristorcelli, J. R.

We investigate coupled stochastic differential equations governing N non-negative continuous random variables that satisfy a conservation principle. In various fields a conservation law requires that a set of fluctuating variables be non-negative and (if appropriately normalized) sum to one. As a result, any stochastic differential equation model to be realizable must not produce events outside of the allowed sample space. We develop a set of constraints on the drift and diffusion terms of such stochastic models to ensure that both the non-negativity and the unit-sum conservation law constraint are satisfied as the variables evolve in time. We investigate the consequencesmore » of the developed constraints on the Fokker-Planck equation, the associated system of stochastic differential equations, and the evolution equations of the first four moments of the probability density function. We show that random variables, satisfying a conservation law constraint, represented by stochastic diffusion processes, must have diffusion terms that are coupled and nonlinear. The set of constraints developed enables the development of statistical representations of fluctuating variables satisfying a conservation law. We exemplify the results with the bivariate beta process and the multivariate Wright-Fisher, Dirichlet, and Lochner’s generalized Dirichlet processes.« less
Onset of anomalous diffusion from local motion rules

NASA Astrophysics Data System (ADS)

de Nigris, Sarah; Carletti, Timoteo; Lambiotte, Renaud

2017-02-01

Anomalous diffusion processes, in particular superdiffusive ones, are known to be efficient strategies for searching and navigation in animals and also in human mobility. One way to create such regimes are Lévy flights, where the walkers are allowed to perform jumps, the "flights," that can eventually be very long as their length distribution is asymptotically power-law distributed. In our work, we present a model in which walkers are allowed to perform, on a one-dimensional lattice, "cascades" of n unitary steps instead of one jump of a randomly generated length, as in the Lévy case, where n is drawn from a cascade distribution pn. We show that this local mechanism may give rise to superdiffusion or normal diffusion when pn is distributed as a power law. We also introduce waiting times that are power-law distributed as well and therefore the probability distribution scaling is steered by the two local distributions power-law exponents. As a perspective, our approach may engender a possible generalization of anomalous diffusion in context where distances are difficult to define, as in the case of complex networks, and also provide an interesting model for diffusion in temporal networks.
Helicopter Control Energy Reduction Using Moving Horizontal Tail

PubMed Central

Oktay, Tugrul; Sal, Firat

2015-01-01

Helicopter moving horizontal tail (i.e., MHT) strategy is applied in order to save helicopter flight control system (i.e., FCS) energy. For this intention complex, physics-based, control-oriented nonlinear helicopter models are used. Equations of MHT are integrated into these models and they are together linearized around straight level flight condition. A specific variance constrained control strategy, namely, output variance constrained Control (i.e., OVC) is utilized for helicopter FCS. Control energy savings due to this MHT idea with respect to a conventional helicopter are calculated. Parameters of helicopter FCS and dimensions of MHT are simultaneously optimized using a stochastic optimization method, namely, simultaneous perturbation stochastic approximation (i.e., SPSA). In order to observe improvement in behaviors of classical controls closed loop analyses are done. PMID:26180841
A High-Throughput Processor for Flight Control Research Using Small UAVs

NASA Technical Reports Server (NTRS)

Klenke, Robert H.; Sleeman, W. C., IV; Motter, Mark A.

2006-01-01

There are numerous autopilot systems that are commercially available for small (<100 lbs) UAVs. However, they all share several key disadvantages for conducting aerodynamic research, chief amongst which is the fact that most utilize older, slower, 8- or 16-bit microcontroller technologies. This paper describes the development and testing of a flight control system (FCS) for small UAV s based on a modern, high throughput, embedded processor. In addition, this FCS platform contains user-configurable hardware resources in the form of a Field Programmable Gate Array (FPGA) that can be used to implement custom, application-specific hardware. This hardware can be used to off-load routine tasks such as sensor data collection, from the FCS processor thereby further increasing the computational throughput of the system.
Energy and variance budgets of a diffusive staircase with implications for heat flux scaling

NASA Astrophysics Data System (ADS)

Hieronymus, M.; Carpenter, J. R.

2016-02-01

Diffusive convection, the mode of double-diffusive convection that occur when both temperature and salinity increase with increasing depth, is commonplace throughout the high latitude oceans and diffusive staircases constitute an important heat transport process in the Arctic Ocean. Heat and buoyancy fluxes through these staircases are often estimated using flux laws deduced either from laboratory experiments, or from simplified energy or variance budgets. We have done direct numerical simulations of double-diffusive convection at a range of Rayleigh numbers and quantified the energy and variance budgets in detail. This allows us to compare the fluxes in our simulations to those derived using known flux laws and to quantify how well the simplified energy and variance budgets approximate the full budgets. The fluxes are found to agree well with earlier estimates at high Rayleigh numbers, but we find large deviations at low Rayleigh numbers. The close ties between the heat and buoyancy fluxes and the budgets of thermal variance and energy have been utilized to derive heat flux scaling laws in the field of thermal convection. The result is the so called GL-theory, which has been found to give accurate heat flux scaling laws in a very wide parameter range. Diffusive convection has many similarities to thermal convection and an extension of the GL-theory to diffusive convection is also presented and its predictions are compared to the results from our numerical simulations.
TrackArt: the user friendly interface for single molecule tracking data analysis and simulation applied to complex diffusion in mica supported lipid bilayers.

PubMed

Matysik, Artur; Kraut, Rachel S

2014-05-01

Single molecule tracking (SMT) analysis of fluorescently tagged lipid and protein probes is an attractive alternative to ensemble averaged methods such as fluorescence correlation spectroscopy (FCS) or fluorescence recovery after photobleaching (FRAP) for measuring diffusion in artificial and plasma membranes. The meaningful estimation of diffusion coefficients and their errors is however not straightforward, and is heavily dependent on sample type, acquisition method, and equipment used. Many approaches require advanced computing and programming skills for their implementation. Here we present TrackArt software, an accessible graphic interface for simulation and complex analysis of multiple particle paths. Imported trajectories can be filtered to eliminate spurious or corrupted tracks, and are then analyzed using several previously described methodologies, to yield single or multiple diffusion coefficients, their population fractions, and estimated errors. We use TrackArt to analyze the single-molecule diffusion behavior of a sphingolipid analog SM-Atto647N, in mica supported DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine) bilayers. Fitting with a two-component diffusion model confirms the existence of two separate populations of diffusing particles in these bilayers on mica. As a demonstration of the TrackArt workflow, we characterize and discuss the effective activation energies required to increase the diffusion rates of these populations, obtained from Arrhenius plots of temperature-dependent diffusion. Finally, TrackArt provides a simulation module, allowing the user to generate models with multiple particle trajectories, diffusing with different characteristics. Maps of domains, acting as impermeable or permeable obstacles for particles diffusing with given rate constants and diffusion coefficients, can be simulated or imported from an image. Importantly, this allows one to use simulated data with a known diffusion behavior as a comparison for results acquired using particular algorithms on actual, "natural" samples whose diffusion behavior is to be extracted. It can also serve as a tool for demonstrating diffusion principles. TrackArt is an open source, platform-independent, Matlab-based graphical user interface, and is easy to use even for those unfamiliar with the Matlab programming environment. TrackArt can be used for accurate simulation and analysis of complex diffusion data, such as diffusion in lipid bilayers, providing publication-quality formatted results.
Diffusion constant of slowly rotating black three-brane

NASA Astrophysics Data System (ADS)

Amoozad, Z.; Sadeghi, J.

2018-01-01

In this paper, we take the slowly rotating black three-brane background and perturb it by introducing a vector gauge field. We find the components of the gauge field through Maxwell equations and Bianchi identities. Using currents and some ansatz we find Fick's first law at long wavelength regime. An interesting result for this non-trivial supergravity background is that the diffusion constant on the stretched horizon which emerges from Fick's first law is a complex constant. The pure imaginary part of the diffusion constant appears because the black three-brane has angular momentum. By taking the static limit of the corresponding black brane the well known diffusion constant will be recovered. On the other hand, from the point of view of the Fick's second law, we have the dispersion relation ω = - iDq2 and we found a damping of hydrodynamical flow in the holographically dual theory. Existence of imaginary term in the diffusion constant introduces an oscillating propagation of the gauge field in the dual field theory.
FCS Academic Programs and Financial Planning Industry: Partnering to Meet Growing Demand

ERIC Educational Resources Information Center

Lytton, Ruth H.; Grable, John E.

2004-01-01

Since the turn of the 20th century and the coalescence of home economics, the use of money within the household has been an issue of study. Now known as family and consumer sciences (FCS), the profession can boast of a century of financial education of youth and adults in a variety of formal and informal settings. In recent decades, financial…
High-throughput dietary exposure predictions for chemical migrants from food contact substances for use in chemical prioritization.

PubMed

Biryol, Derya; Nicolas, Chantel I; Wambaugh, John; Phillips, Katherine; Isaacs, Kristin

2017-11-01

Under the ExpoCast program, United States Environmental Protection Agency (EPA) researchers have developed a high-throughput (HT) framework for estimating aggregate exposures to chemicals from multiple pathways to support rapid prioritization of chemicals. Here, we present methods to estimate HT exposures to chemicals migrating into food from food contact substances (FCS). These methods consisted of combining an empirical model of chemical migration with estimates of daily population food intakes derived from food diaries from the National Health and Nutrition Examination Survey (NHANES). A linear regression model for migration at equilibrium was developed by fitting available migration measurements as a function of temperature, food type (i.e., fatty, aqueous, acidic, alcoholic), initial chemical concentration in the FCS (C 0 ) and chemical properties. The most predictive variables in the resulting model were C 0 , molecular weight, log K ow , and food type (R 2 =0.71, p<0.0001). Migration-based concentrations for 1009 chemicals identified via publicly-available data sources as being present in polymer FCSs were predicted for 12 food groups (combinations of 3 storage temperatures and food type). The model was parameterized with screening-level estimates of C 0 based on the functional role of chemicals in FCS. By combining these concentrations with daily intakes for food groups derived from NHANES, population ingestion exposures of chemical in mg/kg-bodyweight/day (mg/kg-BW/day) were estimated. Calibrated aggregate exposures were estimated for 1931 chemicals by fitting HT FCS and consumer product exposures to exposures inferred from NHANES biomonitoring (R 2 =0.61, p<0.001); both FCS and consumer product pathway exposures were significantly predictive of inferred exposures. Including the FCS pathway significantly impacted the ratio of predicted exposures to those estimated to produce steady-state blood concentrations equal to in-vitro bioactive concentrations. While these HT methods have large uncertainties (and thus may not be appropriate for assessments of single chemicals), they can provide critical refinement to aggregate exposure predictions used in risk-based chemical priority-setting. Published by Elsevier Ltd.
Enzymatic fuel cells with an oxygen resistant variant of pyranose-2-oxidase as anode biocatalyst.

PubMed

Şahin, Samet; Wongnate, Thanyaporn; Chuaboon, Litavadee; Chaiyen, Pimchai; Yu, Eileen Hao

2018-06-01

In enzymatic fuel cells (EnFCs), hydrogen peroxide formation is one of the main problems when enzymes, such as, glucose oxidase (GOx) is used due to the conversion of oxygen to hydrogen peroxide in the catalytic reaction. To address this problem, we here report the first demonstration of an EnFC using a variant of pyranose-2-oxidase (P2O-T169G) which has been shown to have low activity towards oxygen. A simple and biocompatible immobilisation approach incorporating multi-walled-carbon nanotubes within ferrocene (Fc)-Nafion film was implemented to construct EnFCs. Successful immobilisation of the enzymes was demonstrated showing 3.2 and 1.7-fold higher current than when P2O-T169G and GOx were used in solution, respectively. P2O-T169G showed 25% higher power output (maximum power density value of 8.45 ± 1.6 μW cm -2 ) and better stability than GOx in aerated glucose solutions. P2O-T169G maintained > 70% of its initial current whereas GOx lost activity > 90% during the first hour of 12 h operation at 0.15 V (vs Ag/Ag + ). A different fuel cell configuration using gas-diffusion cathode and carbon paper electrodes were used to improve the power output of the fuel cell to 29.8 ± 6.1 µW cm -2 . This study suggests that P2O-T169G with low oxygen activity could be a promising anode biocatalyst for EnFC applications. Copyright © 2018. Published by Elsevier B.V.
Best management practices for nutrient and sediment retention in urban stormwater runoff.

PubMed

Hogan, Dianna M; Walbridge, Mark R

2007-01-01

Stormwater management infrastructure is utilized in urban areas to alleviate flooding caused by decreased landscape permeability from increased impervious surface cover (ISC) construction. In this study, we examined two types of stormwater detention basins, SDB-BMPs (stormwater detention basin-best management practice), and SDB-FCs (stormwater detention basin-flood control). Both are constructed to retain peak stormwater flows for flood mitigation. However, the SDB-BMPs are also designed using basin topography and wetland vegetation to provide water quality improvement (nutrient and sediment removal and retention). The objective of this study was to compare SDB (both SDB-BMP and SDB-FC) surface soil P concentrations, P saturation, and Fe chemistry with natural riparian wetlands (RWs), using sites in Fairfax County, Virginia as a model system. The SDB-BMPs had significantly greater surface soil total P (P(t)) concentrations than the RWs and SDB-FCs (831.9 +/- 32.5 kg ha(-1), 643.3 +/- 19.1 kg ha(-1), and 652.1 +/- 18.8 kg ha(-1), respectively). The soil P sorption capacities of SDB-BMPs were similar to the RWs, and were greater than those of SDB-FCs, appearing to result in greater soil P removal and retention in SDB-BMPs compared with SDB-FCs. Increased Fe concentrations and relatively greater amounts of more crystalline forms of Fe in SDB-BMP soils suggested increased sediment deposition compared with RW and SDB-FC soils. Data suggest that SDB nutrient and sediment retention is facilitated in SDB-BMPs. When stormwater management is necessary, use of SDB-BMPs instead of SDB-FCs could foster more responsible urban development and be an appropriate mitigation action for receiving aquatic ecosystems.
Energy metabolism of leukemia cells: glycolysis versus oxidative phosphorylation.

PubMed

Suganuma, Kazuto; Miwa, Hiroshi; Imai, Norikazu; Shikami, Masato; Gotou, Mayuko; Goto, Mineaki; Mizuno, Shohei; Takahashi, Miyuki; Yamamoto, Hidesuke; Hiramatsu, Akihito; Wakabayashi, Motohiro; Watarai, Masaya; Hanamura, Ichiro; Imamura, Akira; Mihara, Hidetsugu; Nitta, Masakazu

2010-11-01

For generation of energy, cancer cells utilize glycolysis more vigorously than oxidative phosphorylation in mitochondria (Warburg effect). We examined the energy metabolism of four leukemia cell lines by using glycolysis inhibitor, 2-deoxy-d-glucose (2-DG) and inhibitor of oxidative phosphorylation, oligomycin. NB4 was relatively sensitive to 2-DG (IC(50): 5.75 mM), consumed more glucose and produced more lactate (waste product of glycolysis) than the three other cell lines. Consequently, NB4 was considered as a "glycolytic" leukemia cell line. Dependency on glycolysis in NB4 was confirmed by the fact that glucose (+) FCS (-) medium showed more growth and survival than glucose (-) FCS (+) medium. Alternatively, THP-1, most resistant to 2-DG (IC(50): 16.14 mM), was most sensitive to oligomycin. Thus, THP-1 was recognized to be dependent on oxidative phosphorylation. In THP-1, glucose (-) FCS (+) medium showed more growth and survival than glucose (+) FCS (-) medium. The dependency of THP-1 on FCS was explained, at least partly, by fatty acid oxidation because inhibitor of fatty acid β-oxidation, etomoxir, augmented the growth suppression of THP-1 by 2-DG. We also examined the mechanisms by which THP-1 was resistant to, and NB4 was sensitive to 2-DG treatment. In THP-1, AMP kinase (AMPK), which is activated when ATP becomes limiting, was rapidly phosphorylated by 2-DG, and expression of Bcl-2 was augmented, which might result in resistance to 2-DG. On the other hand, AMPK phosphorylation and augmentation of Bcl-2 expression by 2-DG were not observed in NB4, which is 2-DG sensitive. These results will facilitate the future leukemia therapy targeting metabolic pathways.
Disruption of adherens junction and alterations in YAP-related proliferation behavior as part of the underlying cell transformation process of alcohol-induced oral carcinogenesis.

PubMed

Husari, Ayman; Hülter-Hassler, Diana; Steinberg, Thorsten; Schulz, Simon Daniel; Tomakidi, Pascal

2018-01-01

Accumulating evidences indicate that alcohol might play a causative in oral cancer. Unfortunately, in vitro cell systems, uncovering the molecular background of the underlying cell transformation process, are rare. Therefore, this study was conducted, to identify molecular changes and characterize their putative cell behavioral consequences in epitheloid (EPI) and fibroblastoid (FIB) oral keratinocyte phenotypes, arising from chronical alcohol treatment. Concerning adherens junctions (AJs), both EPI and FIB showed membrane-bound β-catenin, but exhibited differences for E-cadherin and zyxin. While EPI revealed E-cadherin/β-catenin membrane co-localization, which in parts also applied for zyxin, FIB membranes were devoid of E-cadherin and exhibited marginal zyxin expression. Fetal calf serum (FCS) administration in starved cells promoted proliferation in both keratinocyte phenotypes, whereat EPI and FIB yielded a strikingly modified FCS sensitivity on the temporal scale. Impedance measurement-based cell index detection yielded proliferation stimulation occurring much earlier in FIB (<20h) compared to EPI (>45h). Nuclear preference of the proliferation-associated YAP co-transcription factor in FIB was FCS independent, while it required FCS in EPI. Taken together, the lack of membrane-inherent E-cadherin/β-catenin co-localization together with low zyxin - reveals perturbation of AJ integrity in FIB. Regarding cell behavior, perturbed AJs in FIB correlate with temporal proliferation sensitivity towards FCS. CYF of 5.6 strongly suggests involvement of chromatin-bound YAP in FIB's proliferation temperosensitivity. These molecular differences detected for EPI and FIB are part of the underlying cell transformation process of alcohol-induced oral carcinogenesis, and indicate FIB being in a more advanced transformation stage. Copyright © 2017 Elsevier B.V. All rights reserved.
Best management practices for nutrient and sediment retention in urban stormwater runoff

USGS Publications Warehouse

Hogan, D.M.; Walbridge, M.R.

2007-01-01

Stormwater management infrastructure is utilized in urban areas to alleviate flooding caused by decreased landscape permeability from increased impervious surface cover (ISC) construction. In this study, we examined two types of stormwater detention basins, SDB-BMPs (stormwater detention basin-best management practice), and SDB-FCs (stormwater detention basin-flood control). Both are constructed to retain peak stormwater flows for flood mitigation. However, the SDB-BMPs are also designed using basin topography and wetland vegetation to provide water quality improvement (nutrient and sediment removal and retention). The objective of this study was to compare SDB (both SDB-BMP and SDB-FC) surface soil P concentrations, P saturation, and Fe chemistry with natural riparian wetlands (RWs), using sites in Fairfax County, Virginia as a model system. The SDB-BMPs had significantly greater surface soil total P (Pt) concentrations than the RWs and SDB-FCs (831.9 ?? 32.5 kg ha-1, 643.3 ?? 19.1 kg ha-1, and 652.1 ?? 18.8 kg ha-1, respectively). The soil P sorption capacities of SDB-BMPs were similar to the RWs, and were greater than those of SDB-FCs, appearing to result in greater soil P removal and retention in SDB-BMPs compared with SDB-FCs. Increased Fe concentrations and relatively greater amounts of more crystalline forms of Fe in SDB-BMP soils suggested increased sediment deposition compared with RW and SDB-FC soils. Data suggest that SDB nutrient and sediment retention is facilitated in SDB-BMPs. When stormwater management is necessary, use of SDB-BMPs instead of SDB-FCs could foster more responsible urban development and be an appropriate mitigation action for receiving aquatic ecosystems. ?? ASA, CSSA, SSSA.
Cross-sectional survey of indicator and pathogenic bacteria on vegetables sold from Asian vendors at farmers' markets in northern California.

PubMed

Pan, Fengguang; Li, Xunde; Carabez, Jennifer; Ragosta, Guy; Fernandez, Kristine L; Wang, Elaine; Thiptara, Anyarat; Antaki, Elizabeth; Atwill, Edward R

2015-03-01

A cross-sectional survey was conducted during summer 2013 to determine the occurrence of Escherichia coli, fecal coliforms (FCs), E. coli O157:H7, and Salmonella on raw vegetable commodities common to Asian cuisine from 21 vendors or farmers at six farmers' markets in northern California. Based on 242 samples from six commodities (basil, yardlong beans, bitter squash, okra, squash stems and leaves, cilantro), 100% of samples had detectable FCs and 20% had detectable E. coli. The mean concentrations were 0.67 log CFU/g and 1.26 log CFU per bundle for E. coli and 4.00 log CFU/g and 6.26 log CFU per bundle for FCs. Vegetables irrigated with ground versus surface water contained lower concentrations of FCs, but this difference was not observed for E. coli. Yardlong beans, bitter squash, and okra had lower levels of FCs compared with basil, cilantro, and squash stems and leaves. Sixteen (6.6%) samples had detectable levels of Salmonella serovars (Newport, Enteritidis, Agona, and Worthington), with the majority of positives found in cilantro and squash stems and leaves. There was a twofold higher probability of Salmonella contamination in samples from growers or vendors who stated that they used organic farming practices compared with samples from those using conventional farming practices. Lastly, the concentrations of FC and E. coli bacteria were significantly associated with Salmonella contamination: for each additional 100 CFU/g or bundle, the probability of Salmonella contamination increased by ∼15 and ∼30%, respectively. None of the samples had detectable E. coli O157:H7.
Modulation of flyash-induced genotoxicity in Vicia faba by vermicomposting.

PubMed

Jain, Kavindra; Singh, Jitendra; Chauhan, L K S; Murthy, R C; Gupta, S K

2004-09-01

Cytogenetic effects of pre- and postvermicomposted flyash samples were evaluated on the root meristem cells of Vicia faba. Seedlings of V. faba were directly sown in flyash and cow dung-soil mixtures (20%, 40%, 60%, and 80%) and the lateral roots grown in these test mixtures were sampled at 5 days. Negative control was run parallel in cow dung-soil (CS) mixture alone. One set of flyash-cow dung-soil (FCS) mixture was subjected to vermicomposting by introducing Eisenia foetida species of earthworms for 30 days and the cytogenetic effects were reinvestigated through V. faba root meristems. Chemical analysis carried out prior to vermicomposting revealed high concentrations of heavy metals such as Cr, Cu, Pb, Zn, and Ni in FCS samples. CS samples also showed the presence of these metals. Cytogenetic examinations of root meristems exposed to the FCS mixtures showed significant inhibition of mitotic index (MI), induction of chromosome aberrations (CA), and a significantly increased frequency of mitotic aberrations (MA). The increase of the aberrations was dependent on the flyash concentrations. Roots grown in CS samples also showed chromosomal and MAs; however, the percentage was lower than that observed with FCS and also statistically nonsignificant. Cytogenetic analysis of vermicomposted samples of FCS revealed a 15-45% decline in the aberration frequencies whereas chemical analysis showed a 10-50% decline in the metal concentrations, viz. Cr, Cu, Pb, Zn, and Ni, which indicates E. foetida a potential accumulator of heavy metals and the decline in metal concentrations may be the cause of the decrease in aberration frequencies. The present study indicates the genotoxicity potential of flyash and also the feasibility of vermicomposting for cleanup of metal-contaminated soil to mitigate the toxicity/genotoxicity. Copyright 2004 Elsevier Inc.
Effect of Diffuse Backscatter in Cassini Datasets on the Inferred Properties of Titan's surface

NASA Astrophysics Data System (ADS)

Sultan-Salem, A. K.; Tyler, G. L.

2006-12-01

Microwave (2.18 cm-λ) backscatter data for the surface of Titan obtained with the Cassini Radar instrument exhibit a significant diffuse scattering component. An empirical scattering law of the form Acos^{n}θ, with free parameters A and n, is often employed to model diffuse scattering, which may involve one or more unidentified mechanisms and processes, such as volume scattering and scattering from surface structure that is much smaller than the electromagnetic wavelength used to probe the surface. The cosine law in general is not explicit in its dependence on either the surface structure or electromagnetic parameters. Further, the cosine law often is only a poor representation of the observed diffuse scattering, as can be inferred from computation of standard goodness-of-fit measures such as the statistical significance. We fit four Cassini datasets (TA Inbound and Outbound, T3 Outbound, and T8 Inbound) with a linear combination of a cosine law and a generalized fractal-based quasi-specular scattering law (A. K. Sultan- Salem and G. L. Tyler, J. Geophys. Res., 111, E06S08, doi:10.1029/2005JE002540, 2006), in order to demonstrate how the presence of diffuse scattering increases considerably the uncertainty in surface parameters inferred from the quasi-specular component, typically the dielectric constant of the surface material and the surface root-mean-square slope. This uncertainty impacts inferences concerning the physical properties of the surfaces that display mixed scattering properties.

Creating the final conversations scale: a measure of end-of-life relational communication with terminally ill individuals.

PubMed

Generous, Mark Alan; Keeley, Maureen P

2014-01-01

Final conversations (FCs) are defined as the communicative interactions, both verbal and nonverbal, that occur between terminally ill patients and relational partners. In this study, the "Final Conversations Scale" was developed and tested. A total of 152 participants that had engaged in final conversations with individuals that were terminally ill completed the newly developed instrument. Factor analysis produced a five-factor structure, including: messages of spirituality/religion; expressions of love; proactive difficult relationship talk; everyday communication; and talk about illness/death. Participants' perceptions of the relational closeness and difficulty with the deceased significantly influenced the individuals' recalled frequency of FCs messages. Practical and scholarly implications focus on the needs of the family members regarding their communication with terminally ill individuals, as well as directions for future research with the FCs Scale.
Antithrombotic activities of fucosylated chondroitin sulfates and their depolymerized fragments from two sea cucumbers.

PubMed

Liu, Xiaoxiao; Hao, Jiejie; Shan, Xindi; Zhang, Xiao; Zhao, Xiaoliang; Li, Qinying; Wang, Xiaojiang; Cai, Chao; Li, Guoyun; Yu, Guangli

2016-11-05

Fucosylated chondroitin sulfate (FCS), a glycosaminoglycan extracted from the body wall of sea cucumber, is a promising antithrombotic agent. The chemical structures of FCSc isolated from sea cucumber Cucumaria frondosa and its depolymerized fragment (dFCSc) were characterized for the first time. Additionally, anticoagulant and antithrombotic activities were evaluated in vitro and in vivo. The results demonstrated that dFCSc exhibited better antithrombotic-hemorrhagic ratio than native FCSc on the electrical induced arterial thrombosis model in rats. Compared to FCSt obtained from Thelenota ananas, FCSc possessed different sulfation patterns but similar antithrombotic effects. Therefore, sulfation pattern of FCS might not affect anticoagulation and antithrombosis as much as molecular weight may. Our results proposed a new point of view to understand the structure-activity relationship of FCS as alternative agents. Copyright © 2016 Elsevier Ltd. All rights reserved.
A Flight Control System for Small Unmanned Aerial Vehicle

NASA Astrophysics Data System (ADS)

Tunik, A. A.; Nadsadnaya, O. I.

2018-03-01

The program adaptation of the controller for the flight control system (FCS) of an unmanned aerial vehicle (UAV) is considered. Linearized flight dynamic models depend mainly on the true airspeed of the UAV, which is measured by the onboard air data system. This enables its use for program adaptation of the FCS over the full range of altitudes and velocities, which define the flight operating range. FCS with program adaptation, based on static feedback (SF), is selected. The SF parameters for every sub-range of the true airspeed are determined using the linear matrix inequality approach in the case of discrete systems for synthesis of a suboptimal robust H ∞-controller. The use of the Lagrange interpolation between true airspeed sub-ranges provides continuous adaptation. The efficiency of the proposed approach is shown against an example of the heading stabilization system.
California Community College Family and Consumer Sciences Program Plan, 1996. Including: Directory of Professional and Trade Organizations, Directory of Family and Consumer Sciences and Related Program Areas and Program Coordinators.

ERIC Educational Resources Information Center

California Community Colleges, Sacramento. Office of the Chancellor.

Intended as a resource for California community colleges and districts in assessing and improving family and consumer science (FCS) programs, this program plan provides information on current trends affecting the delivery of FCS programs and guidelines for assessing and developing new comprehensive or specialized programs. Following letters of…
Platelet Lysate: The Better Choice for Jaw Periosteal Cell Mineralization.

PubMed

Wanner, Yvonne; Umrath, Felix; Waidmann, Marc; Reinert, Siegmar; Alexander, Dorothea

2017-01-01

Previously, we demonstrated a high quality of minerals formed by serum-free cultured jaw periosteal cells (JPCs) by Raman spectroscopy but the mineralization extent was not satisfactory. In the present study, we analyzed the proliferation and mineralization potential of human platelet lysate- (hPL-) cultured JPCs in comparison to that of FCS-cultured JPCs. By cell impedance measurements, we detected significantly higher population doubling times of PL-cultured JPCs in comparison to FCS-cultured JPCs. However, this result was not based on lower proliferation activities but on diminished cell sizes which JPCs develop under PL cultivation. The measurements of the metabolic activities clearly showed significantly higher cell proliferation rates under PL culturing. Equivalent levels of the mesenchymal cell markers CD29, CD45, CD73, CD90, and CD105 were detected, but there were significantly increased MSCA-1 levels under PL cultivation. While JPCs only occasionally mineralize under FCS culture conditions, the mineralization potential was significantly stronger under PL cultivation. Moreover, in 4 of 5 analyzed patient cells, the addition of dexamethasone was proved no longer necessary for strong mineralization of PL-cultured JPCs. We conclude that in vitro cultivation of JPCs with platelet lysate is a suitable alternative to FCS culture conditions and a powerful tool for the development of high-quality TE constructs using jaw periosteal cells.
Organization of the nucleoli of soybean root meristematic cells at different states of their activity.

PubMed

Stepiński, Dariusz

2010-06-01

Internal organization of a nucleolus changes along with rRNA transcriptional activity. These changes mainly concern qualitative and quantitative alternations of three main nucleolar components: fibrillar centres (FC), dense fibrillar component (DFC) and granular component (GC). In the present work quantitative measurements of the number and sizes of FCs and DFCs in nucleoli of root meristematic cells of soybean seedlings grown at (1) chilling conditions that reduce transcriptional activity of soybean nucleoli (temp. of 10 degrees C) and at (2) conditions that increase this activity (recovery at optimal temp. of 25 degrees C after previous chilling), even more than (3) the control, have been carried out. Morphometric measurements showed that the highest number of FCs and DFCs was in the most active nucleoli, while the smallest number - in those with the lowest activity. The average size of an individual FC was similar in all nucleoli regardless of their transcriptional activity, that of the individual DFC varied, being bigger in the nucleoli of the chilled plants and smallest in those of the recovered plants. The numbers of FCs and DFCs seem to be indicators of transcriptional activity of plant nucleoli - the higher number of FCs and DFCs the more active nucleoli. Copyright 2009 Elsevier Ltd. All rights reserved.
GMI High Frequency Antenna Pattern Correction Update Based on GPM Inertial Hold and Comparison with ATMS

NASA Technical Reports Server (NTRS)

Draper, David W.

2015-01-01

In an inertial hold, the spacecraft does not attempt to maintain geodetic pointing, but rather maintains the same inertial position throughout the orbit. The result is that the spacecraft appears to pitch from 0 to 360 degrees around the orbit. Two inertial holds were performed with the GPM spacecraft: 1) May 20, 2014 16:48:31 UTC-18:21:04 UTC, spacecraft flying forward +X (0yaw), pitch from 55 degrees (FCS) to 415 degrees (FCS) over the orbit2) Dec 9, 2014 01:30:00 UTC-03:02:32 UTC, spacecraft flying backward X (180yaw), pitch from 0 degrees (FCS) to 360 degrees (FCS) over the orbitThe inertial hold affords a view of the earth through the antenna backlobe. The antenna spillover correction may be evaluated based on the inertial hold data.The current antenna pattern correction does not correct for spillover in the 166 and 183 GHz channels. The two inertial holds both demonstrate that there is significant spillover from the 166 and 183 GHz channels. By not correcting the spillover, the 166 and 183 GHz channels are biased low by about 1.8 to 3K. We propose to update the GMI calibration algorithm with the spill-over correction presented in this document for 166 GHz and 183 GHz.
Mapping the dynamical organization of the cell nucleus through fluorescence correlation spectroscopy.

PubMed

Stortz, Martin; Angiolini, Juan; Mocskos, Esteban; Wolosiuk, Alejandro; Pecci, Adali; Levi, Valeria

2018-05-01

The hierarchical organization of the cell nucleus into specialized open reservoirs and the nucleoplasm overcrowding impose restrictions to the mobility of biomolecules and their interactions with nuclear targets. These properties determine that many nuclear functions such as transcription, replication, splicing or DNA repair are regulated by complex, dynamical processes that do not follow simple rules. Advanced fluorescence microscopy tools and, in particular, fluorescence correlation spectroscopy (FCS) provide complementary and exquisite information on the dynamics of fluorescent labeled molecules moving through the nuclear space and are helping us to comprehend the complexity of the nuclear structure. Here, we describe how FCS methods can be applied to reveal the dynamical organization of the nucleus in live cells. Specifically, we provide instructions for the preparation of cellular samples with fluorescent tagged proteins and detail how FCS can be easily instrumented in commercial confocal microscopes. In addition, we describe general rules to set the parameters for one and two-color experiments and the required controls for these experiments. Finally, we review the statistical analysis of the FCS data and summarize the use of numerical simulations as a complementary approach that helps us to understand the complex matrix of molecular interactions network within the nucleus. Copyright © 2017 Elsevier Inc. All rights reserved.
Sensing of hydrophobic cavity of serum albumin by an adenosine analogue: fluorescence correlation and ensemble spectroscopic studies.

PubMed

Nag, Moupriya; Bera, Kallol; Chakraborty, Sandipan; Basak, Soumen

2013-10-05

Adenosine is a naturally occurring purine nucleoside that plays important role in various biochemical processes. We have studied the binding of TNP-Ado (trinitrophenylated-adenosine), a fluorescent analogue of adenosine (which itself is a weak fluorophore), with a model transport protein, bovine serum albumin (BSA). The binding affinity was determined using Fluorescence correlation spectroscopy (FCS) and compared with its value obtained from macroscopic fluorescence spectroscopic studies. Fluorescence and circular dichroism (CD) spectroscopies were employed together with molecular docking study to locate the probable binding site of TNP-Ado on BSA and its effect on the conformation and stability of BSA. Fluorescence studies showed that TNP-Ado binds to BSA in 1:1 stoichiometry via an entropically favoured process. Induced CD spectra revealed that a chiro-optical switching of TNP-Ado occurs upon binding to BSA. Results on urea-induced denaturation of BSA and docking study suggested that the binding site for the ligand is in the hydrophobic subdomain IIA of BSA, consistent with the results of other measurements. This study establishes TNP-Ado as a sensor of hydrophobic regions in proteins like serum albumin, having the capability of detecting a minimum concentration of 140ng/ml protein. FCS measurement of binding interaction of rhodamine-labeled TNP-Ado (RTNP-Ado) with BSA yielded an association constant of KFCS=(1.03±0.06) × 10(4)M(-1). The association constants (Ka) obtained for binding of BSA with rhodamine-free (i.e. TNP-Ado) and rhodamine-labeled (RTNP-Ado) ligands, obtained using the ensemble spectroscopic technique, were (2.3±0.06) × 10(5)M(-1) and (3.4±0.03) × 10(4)M(-1), respectively. The difference between the values of Ka for the free and labeled ligands suggests that fluorescent labeling of small molecules perceptibly interferes with the binding process. On the other hand, the difference in Ka obtained by FCS and ensemble techniques is due to the fact that while the former measures the change in the diffusion constant (i.e. size) of RTNP-Ado upon binding to BSA, the latter focuses on the change of tryptophan emission properties of BSA due to the presence of bound RTNP-Ado. Copyright © 2013 Elsevier B.V. All rights reserved.
The Diffusion of Disability Rights Policy: A Focus on Special Education in South Korea

ERIC Educational Resources Information Center

Yoo, Joan P.; Palley, Elizabeth

2014-01-01

This article examines the development of South Korean special education policy and suggests that different strategies of policy diffusion influenced the design of the policy at different times. Historically, South Korea relied on external pressures and influences, particularly US law and UN guidelines, to develop much of its human rights law,…
Fluorescence fluctuation analysis of BACE1-GFP fusion protein in cultured HEK293 cells

NASA Astrophysics Data System (ADS)

Gardeen, Spencer; Johnson, Joseph L.; Heikal, Ahmed A.

2016-10-01

Beta-site APP cleaving enzyme 1 (BACE1) is a type I transmembrane aspartyl protease. In the amyloidogenic pathway, BACE1 provides β-secretase activity that cleaves the amyloid precursor protein (APP) that leads to amyloid beta (Aβ) peptides. The aggregation of these Aβ will ultimately results in amyloid plaque formation, a hallmark of Alzheimer's disease (AD). Amyloid aggregation leads to progressive memory impairment and neural loss. Recent detergent protein extraction studies suggest that the untreated BACE1 protein forms a dimer that has significantly higher catalytic activity than its monomeric counterpart. Here, we examine the dimerization hypothesis of BACE1 in cultured HEK293 cells using fluorescence correlation spectroscopy (FCS). Cells were transfected with a BACE1-EGFP fusion protein construct and imaged using confocal and DIC microscopy to monitor labeled BACE1 localization and distribution within the cell. Our one-photon fluorescence fluctuation autocorrelation of BACE1- EGFP on the plasma membrane of HEK cells is modeled using two diffusing species on the plasma membrane with estimated diffusion coefficients of 1.39 x 10-7 cm2/sec and 2.8 x 10-8 cm2/sec under resting conditions and STA-200 inhibition, respectively. Anomalous diffusion model also provided adequate description of the observed autocorrelation function of BACE1- EGFP on the plasma membrane with an estimate exponent (α) of 0.8 and 0.5 for resting and STA-200 treated cells, respectively. The corresponding hydrodynamic radius of this transmembrane fusion protein was estimated using the measured diffusion coefficients assuming both Stokes-Einstein and Saffman-Delbruck models. Our results suggest a complex diffusion pattern of BACE1-EGFP on the plasma membrane of HEK cells with the possibility for dimer formation, especially under STA-200 inhibition.
An Analysis of the Future Combat Systems (FCS) Spin Out 1 Low-Rate of Initial Production (LRIP) Contract

DTIC Science & Technology

2009-08-24

interests are strategic resource management, strategic control, and corporate financial reporting. Joseph G. San Miguel Professor Graduate School of...Officer PM – Program Manager SAIC – Science Applications International Corporation SAP – Systems Applications and Products SDD – System Development and...the award of the multi-billion dollar FCS program management contract to the Boeing Company and Science Applications International Corporation (SAIC
Qualification of the family caregiver to the application of the Educational Technology in Health.

PubMed

Santos, Paula Dayanna Sousa Dos; Santos, Zélia Maria de Sousa Araújo; Diógenes, Léa Maria Moura Barroso; Caldas, José Manuel Peixoto de; Rodrigues, Kátia Alves Ferreira; Carneiro, Rithianne Frota

2018-05-01

To evaluate the changes in the participation of the family caregiver in the treatment of the hypertensive person with the application of the Educational Technology in Health (ETH). Participant research carried out in a Primary Health Care Unit with 11 family caregivers (FC). The ETH was elaborated based on health education and applied in ten meetings between June and August 2016. We organized the results into categories. FCs experienced learning experiences through the exchange of information, socialization of experiences, and linkage establishments. The FCs were encouraged to share their doubts and experiences, so that, supported by listening to the professional, they felt welcomed and determined to fulfill their role with hypertensive relatives. Final considerations: The changes that have taken place have been highlighted in the learning of FCs and their commitment to family and self-care, as well as to the conviction that the family environment is indicated to make these changes effective.
Human Platelet Lysate versus Fetal Calf Serum: These Supplements Do Not Select for Different Mesenchymal Stromal Cells.

PubMed

Fernandez-Rebollo, Eduardo; Mentrup, Birgit; Ebert, Regina; Franzen, Julia; Abagnale, Giulio; Sieben, Torsten; Ostrowska, Alina; Hoffmann, Per; Roux, Pierre-François; Rath, Björn; Goodhardt, Michele; Lemaitre, Jean-Marc; Bischof, Oliver; Jakob, Franz; Wagner, Wolfgang

2017-07-11

Culture medium of mesenchymal stromal cells (MSCs) is usually supplemented with either human platelet lysate (HPL) or fetal calf serum (FCS). Many studies have demonstrated that proliferation and cellular morphology are affected by these supplements - it is therefore important to determine if they favor outgrowth of different subpopulations and thereby impact on the heterogeneous composition of MSCs. We have isolated and expanded human bone marrow-derived MSCs in parallel with HPL or FCS and demonstrated that HPL significantly increases proliferation and leads to dramatic differences in cellular morphology. Remarkably, global DNA-methylation profiles did not reveal any significant differences. Even at the transcriptomic level, there were only moderate changes in pairwise comparison. Furthermore, the effects on proliferation, cytoskeletal organization, and focal adhesions were reversible by interchanging to opposite culture conditions. These results indicate that cultivation of MSCs with HPL or FCS has no systematic bias for specific cell types.
Foam Core Shielding for Spacecraft

NASA Technical Reports Server (NTRS)

Adams, Marc

2007-01-01

A foam core shield (FCS) system is now being developed to supplant multilayer insulation (MLI) systems heretofore installed on spacecraft for thermal management and protection against meteoroid impacts. A typical FCS system consists of a core sandwiched between a face sheet and a back sheet. The core can consist of any of a variety of low-to-medium-density polymeric or inorganic foams chosen to satisfy application-specific requirements regarding heat transfer and temperature. The face sheet serves to shock and thereby shatter incident meteoroids, and is coated on its outer surface to optimize its absorptance and emittance for regulation of temperature. The back sheet can be dimpled to minimize undesired thermal contact with the underlying spacecraft component and can be metallized on the surface facing the component to optimize its absorptance and emittance. The FCS systems can perform better than do MLI systems, at lower mass and lower cost and with greater volumetric efficiency.
X-38 Application of Dynamic Inversion Flight Control

NASA Technical Reports Server (NTRS)

Wacker, Roger; Munday, Steve; Merkle, Scott

2001-01-01

This paper summarizes the application of a nonlinear dynamic inversion (DI) flight control system (FCS) to an autonomous flight test vehicle in NASA's X-38 Project, a predecessor to the International Space Station (ISS) Crew Return Vehicle (CRV). Honeywell's Multi-Application Control-H (MACH) is a parameterized FCS design architecture including both model-based DI rate-compensation and classical P+I command-tracking. MACH was adopted by X-38 in order to shorten the design cycle time for different vehicle shapes and flight envelopes and evolving aerodynamic databases. Specific design issues and analysis results are presented for the application of MACH to the 3rd free flight (FF3) of X-38 Vehicle 132 (V132). This B-52 drop test, occurring on March 30, 2000, represents the first flight test of MACH and one of the first few known applications of DI in the primary FCS of an autonomous flight test vehicle.
Medial versus anterior open reduction for developmental hip dislocation in age-matched patients.

PubMed

Hoellwarth, Jason S; Kim, Young-Jo; Millis, Michael B; Kasser, James R; Zurakowski, David; Matheney, Travis H

2015-01-01

The difference between medial (MAOR) and anterior (AAOR) approaches for open reduction of developmental hip dysplasia in terms of risk for avascular necrosis (AVN) and need for further corrective surgery (FCS, femoral and/or acetabular osteotomy) is unclear. This study compared age-matched cohorts undergoing either MAOR or AAOR in terms of these 2 primary outcomes. Prognostic impact of presence of ossific nucleus at time of open reduction was also investigated. Institutional review board approval was obtained. Nineteen hips (14 patients) managed by MAOR were matched with 19 hips (18 patients) managed by AAOR based on age at operation (mean 6.0; range, 1.4 to 14.9 mo). Patients with neuromuscular conditions and known connective tissue disorders were excluded. Primary outcomes assessed at minimum 2 years' follow-up included radiographic evidence of AVN (Kalamchi and MacEwen) or requiring FCS. MAOR and AAOR cohorts were similar regarding age at open reduction, sex, laterality, and follow-up duration. One hip in each group had AVN before open reduction thus were excluded from AVN analysis. At minimum 2 years postoperatively (mean 6.2; range, 1.8 to 11.7 y), 4/18 (22%) MAOR and 5/18 (28%) AAOR met the same criteria for AVN (P=1.0). No predictors of AVN could be identified by regression analysis. Presence of an ossific nucleus preoperatively was not a protective factor from AVN (P=0.27). FCS was required in 4/19 (21%) MAOR and 7/19 (37%) AAOR hips (P=0.48). However, 7/12 (54%) hips failing closed reduction required FCS compared with 4/26 (16%) hips without prior failed closed reduction (P=0.024). Cox regression analysis showed that patients who failed closed reduction had an annual risk of requiring FCS approximately 6 times that of patients without a history of failed closed reduction (hazard ratio=6.1; 95% CI, 1.5-24.4; P=0.009), independent of surgical approach (P=0.55) or length of follow-up (P=0.78). In this study of age-matched patients undergoing either MAOR or AAOR, we found no association between surgical approach and risk of AVN or FCS. In addition, we identified no protective benefit of a preoperative ossific nucleus in terms of development of AVN. However, failing closed reduction was associated with a 6-fold increased annual risk of requiring FCS. To the best of our knowledge, this is the first study comparing these 2 surgical techniques in an age-matched manner. It further corroborates previous studies stating that there may be no difference in risk of AVN based on surgical approach or presence of ossific nucleus preoperatively. Level III-retrospective comparative study.
Spatial fluorescence cross-correlation spectroscopy between core and ring pinholes

NASA Astrophysics Data System (ADS)

Blancquaert, Yoann; Delon, Antoine; Derouard, Jacques; Jaffiol, Rodolphe

2006-04-01

Fluorescence Correlation Spectroscopy (FCS) is an attractive method to measure molecular concentration, mobility parameters and chemical kinetics. However its ability to descriminate different diffusing species needs to be improved. Recently, we have proposed a simplified spatial Fluorescence cross Correlation Spectroscopy (sFCCS) method, allowing, with only one focused laser beam to obtain two confocal volumes spatially shifted. Now, we present a new sFCCS optical geometry where the two pinholes, a ring and core, are encapsulated one in the other. In this approach all physical and chemical processes that occur in a single volume, like singlet-triplet dynamics and photobleaching, can be eliminated; moreover, this new optical geometry optimises the collection of fluorescence. The first cross Correlation curves for Rhodamine 6G (Rh6G) in Ethanol are presented, in addition to the effect of the size of fluorescent particules (nano-beads, diameters : 20, 100 and 200 nm). The relative simplicity of the method leads us to propose sFCCS as an appropriate method for the determination of diffusion parameters of fluorophores in solution or cells. Nevertheless, progresses in the ingeniering of the optical Molecular Detection Efficiency volumes are highly desirable, in order to improve the descrimination between the cross correlated volumes.
Posing for a picture: vesicle immobilization in agarose gel

NASA Astrophysics Data System (ADS)

Lira, Rafael B.; Steinkühler, Jan; Knorr, Roland L.; Dimova, Rumiana; Riske, Karin A.

2016-05-01

Taking a photo typically requires the object of interest to stand still. In science, imaging is potentiated by optical and electron microscopy. However, living and soft matter are not still. Thus, biological preparations for microscopy usually include a fixation step. Similarly, immobilization strategies are required for or substantially facilitate imaging of cells or lipid vesicles, and even more so for acquiring high-quality data via fluorescence-based techniques. Here, we describe a simple yet efficient method to immobilize objects such as lipid vesicles with sizes between 0.1 and 100 μm using agarose gel. We show that while large and giant unilamellar vesicles (LUVs and GUVs) can be caged in the pockets of the gel meshwork, small molecules, proteins and micelles remain free to diffuse through the gel and interact with membranes as in agarose-free solutions, and complex biochemical reactions involving several proteins can proceed in the gel. At the same time, immobilization in agarose has no adverse effect on the GUV size and stability. By applying techniques such as FRAP and FCS, we show that the lateral diffusion of lipids is not affected by the gel. Finally, our immobilization strategy allows capturing high-resolution 3D images of GUVs.
Meaningful interpretation of subdiffusive measurements in living cells (crowded environment) by fluorescence fluctuation microscopy.

PubMed

Baumann, Gerd; Place, Robert F; Földes-Papp, Zeno

2010-08-01

In living cell or its nucleus, the motions of molecules are complicated due to the large crowding and expected heterogeneity of the intracellular environment. Randomness in cellular systems can be either spatial (anomalous) or temporal (heterogeneous). In order to separate both processes, we introduce anomalous random walks on fractals that represented crowded environments. We report the use of numerical simulation and experimental data of single-molecule detection by fluorescence fluctuation microscopy for detecting resolution limits of different mobile fractions in crowded environment of living cells. We simulate the time scale behavior of diffusion times tau(D)(tau) for one component, e.g. the fast mobile fraction, and a second component, e.g. the slow mobile fraction. The less the anomalous exponent alpha the higher the geometric crowding of the underlying structure of motion that is quantified by the ratio of the Hausdorff dimension and the walk exponent d(f)/d(w) and specific for the type of crowding generator used. The simulated diffusion time decreases for smaller values of alpha # 1 but increases for a larger time scale tau at a given value of alpha # 1. The effect of translational anomalous motion is substantially greater if alpha differs much from 1. An alpha value close to 1 contributes little to the time dependence of subdiffusive motions. Thus, quantitative determination of molecular weights from measured diffusion times and apparent diffusion coefficients, respectively, in temporal auto- and crosscorrelation analyses and from time-dependent fluorescence imaging data are difficult to interpret and biased in crowded environments of living cells and their cellular compartments; anomalous dynamics on different time scales tau must be coupled with the quantitative analysis of how experimental parameters change with predictions from simulated subdiffusive dynamics of molecular motions and mechanistic models. We first demonstrate that the crowding exponent alpha also determines the resolution of differences in diffusion times between two components in addition to photophysical parameters well-known for normal motion in dilute solution. The resolution limit between two different kinds of single molecule species is also analyzed under translational anomalous motion with broken ergodicity. We apply our theoretical predictions of diffusion times and lower limits for the time resolution of two components to fluorescence images in human prostate cancer cells transfected with GFP-Ago2 and GFP-Ago1. In order to mimic heterogeneous behavior in crowded environments of living cells, we need to introduce so-called continuous time random walks (CTRW). CTRWs were originally performed on regular lattice. This purely stochastic molecule behavior leads to subdiffusive motion with broken ergodicity in our simulations. For the first time, we are able to quantitatively differentiate between anomalous motion without broken ergodicity and anomalous motion with broken ergodicity in time-dependent fluorescence microscopy data sets of living cells. Since the experimental conditions to measure a selfsame molecule over an extended period of time, at which biology is taken place, in living cells or even in dilute solution are very restrictive, we need to perform the time average over a subpopulation of different single molecules of the same kind. For time averages over subpopulations of single molecules, the temporal auto- and crosscorrelation functions are first found. Knowing the crowding parameter alpha for the cell type and cellular compartment type, respectively, the heterogeneous parameter gamma can be obtained from the measurements in the presence of the interacting reaction partner, e.g. ligand, with the same alpha value. The product alpha x gamma = gamma is not a simple fitting parameter in the temporal auto- and two-color crosscorrelation functions because it is related to the proper physical models of anomalous (spatial) and heterogeneous (temporal) randomness in cellular systems.We have already derived an analytical solution gamma for in the special case of gamma = 3/2. In the case of two-color crosscorrelation or/and two-color fluorescence imaging (co-localization experiments), the second component is also a two-color species gr, for example a different molecular complex with an additional ligand. Here, we first show that plausible biological mechanisms from FCS/ FCCS and fluorescence imaging in living cells are highly questionable without proper quantitative physical models of subdiffusive motion and temporal randomness. At best, such quantitative FCS/ FCCS and fluorescence imaging data are difficult to interpret under crowding and heterogeneous conditions. It is challenging to translate proper physical models of anomalous (spatial) and heterogeneous (temporal) randomness in living cells and their cellular compartments like the nucleus into biological models of the cell biological process under study testable by single-molecule approaches. Otherwise, quantitative FCS/FCCS and fluorescence imaging measurements in living cells are not well described and cannot be interpreted in a meaningful way.

Modified Beer-Lambert law for blood flow.

PubMed

Baker, Wesley B; Parthasarathy, Ashwin B; Busch, David R; Mesquita, Rickson C; Greenberg, Joel H; Yodh, A G

2014-11-01

We develop and validate a Modified Beer-Lambert law for blood flow based on diffuse correlation spectroscopy (DCS) measurements. The new formulation enables blood flow monitoring from temporal intensity autocorrelation function data taken at single or multiple delay-times. Consequentially, the speed of the optical blood flow measurement can be substantially increased. The scheme facilitates blood flow monitoring of highly scattering tissues in geometries wherein light propagation is diffusive or non-diffusive, and it is particularly well-suited for utilization with pressure measurement paradigms that employ differential flow signals to reduce contributions of superficial tissues.
Proteins as micro viscosimeters: Brownian motion revisited.

PubMed

Lavalette, Daniel; Hink, Mark A; Tourbez, Martine; Tétreau, Catherine; Visser, Antonie J

2006-08-01

Translational and rotational diffusion coefficients of proteins in solution strongly deviate from the Stokes-Einstein laws when the ambient viscosity is induced by macromolecular co-solutes rather than by a solvent of negligible size as was assumed by A. Einstein one century ago for deriving the laws of Brownian motion and diffusion. Rotational and translational motions experience different micro viscosities and both become a function of the size ratio of protein and macromolecular co-solute. Possible consequences upon fluorescence spectroscopy observations of diffusing proteins within living cells are discussed.
Effect of a dual inlet channel on cell loading in microfluidics.

PubMed

Yun, Hoyoung; Kim, Kisoo; Lee, Won Gu

2014-11-01

Unwanted sedimentation and attachment of a number of cells onto the bottom channel often occur on relatively large-scale inlets of conventional microfluidic channels as a result of gravity and fluid shear. Phenomena such as sedimentation have become recognized problems that can be overcome by performing microfluidic experiments properly, such as by calculating a meaningful output efficiency with respect to real input. Here, we present a dual-inlet design method for reducing cell loss at the inlet of channels by adding a new " upstream inlet " to a single main inlet design. The simple addition of an upstream inlet can create a vertically layered sheath flow prior to the main inlet for cell loading. The bottom layer flow plays a critical role in preventing the cells from attaching to the bottom of the channel entrance, resulting in a low possibility of cell sedimentation at the main channel entrance. To provide proof-of-concept validation, we applied our design to a microfabricated flow cytometer system (μFCS) and compared the cell counting efficiency of the proposed μFCS with that of the previous single-inlet μFCS and conventional FCS. We used human white blood cells and fluorescent microspheres to quantitatively evaluate the rate of cell sedimentation in the main inlet and to measure fluorescence sensitivity at the detection zone of the flow cytometer microchip. Generating a sheath flow as the bottom layer was meaningfully used to reduce the depth of field as well as the relative deviation of targets in the z-direction (compared to the x-y flow plane), leading to an increased counting sensitivity of fluorescent detection signals. Counting results using fluorescent microspheres showed both a 40% reduction in the rate of sedimentation and a 2-fold higher sensitivity in comparison with the single-inlet μFCS. The results of CD4(+) T-cell counting also showed that the proposed design results in a 25% decrease in the rate of cell sedimentation and a 28% increase in sensitivity when compared to the single-inlet μFCS. This method is simple and easy to use in design, yet requires no additional time or cost in fabrication. Furthermore, we expect that this approach could potentially be helpful for calculating exact cell loading and counting efficiency for a small input number of cells, such as primary cells and rare cells, in microfluidic channel applications.
Dynamics of gas bubble growth in a supersaturated solution with Sievert's solubility law.

PubMed

Gor, G Yu; Kuchma, A E

2009-07-21

This paper presents a theoretical description of diffusion growth of a gas bubble after its nucleation in supersaturated liquid solution. We study systems where gas molecules completely dissociate in the solvent into two parts, thus making Sievert's solubility law valid. We show that the difference between Henry's and Sievert's laws for chemical equilibrium conditions causes the difference in bubble growth dynamics. Assuming that diffusion flux is steady we obtain a differential equation on bubble radius. Bubble dynamics equation is solved analytically for the case of homogeneous nucleation of a bubble, which takes place at a significant pressure drop. We also obtain conditions of diffusion flux steadiness. The fulfillment of these conditions is studied for the case of nucleation of water vapor bubbles in magmatic melts.
A High Performance Frequency Standard and Distribution System for Cassini Ka-Band Experiment

DTIC Science & Technology

2005-08-01

Orthogonal Polarization In Anisotropic Dielectric Resonators”, Proceedings of the 2002 IEEE International Frequency Control Symposium , pp. 553-558...2002. [9] G. J. Dick, Rabi T. Wang, Robert Tjoelker, “Design and Progress Report for Compact Cryocooled Sapphire Oscillator "VCSO"”, Proc. 2005 Joint...IEEE FCS/ PTTI. [10] R. Basu, G. J. Dick, Rabi T. Wang,” Novel Design of an All- Cryogenic RF Pound Circuit “,Proc. 2005 Joint IEEE FCS/ PTTI
Integrating the Department of Defense Military Services’ Technology Development Programs to Improve Time, Cost, and Technical Quality Parameters

DTIC Science & Technology

2007-03-01

the DoD in general and across the SR, DD(X), and FCS programs in particular. The findings of this study show that through careful planning and...FCS programs in particular. The findings of this study show that through careful planning and coordinated technology transition, DoD acquisition...careful planning and coordinated technology transition, DoD acquisition programs can indeed leverage the technology development efforts of the three
Platelet Lysate: The Better Choice for Jaw Periosteal Cell Mineralization

PubMed Central

Wanner, Yvonne; Umrath, Felix; Waidmann, Marc; Reinert, Siegmar

2017-01-01

Previously, we demonstrated a high quality of minerals formed by serum-free cultured jaw periosteal cells (JPCs) by Raman spectroscopy but the mineralization extent was not satisfactory. In the present study, we analyzed the proliferation and mineralization potential of human platelet lysate- (hPL-) cultured JPCs in comparison to that of FCS-cultured JPCs. By cell impedance measurements, we detected significantly higher population doubling times of PL-cultured JPCs in comparison to FCS-cultured JPCs. However, this result was not based on lower proliferation activities but on diminished cell sizes which JPCs develop under PL cultivation. The measurements of the metabolic activities clearly showed significantly higher cell proliferation rates under PL culturing. Equivalent levels of the mesenchymal cell markers CD29, CD45, CD73, CD90, and CD105 were detected, but there were significantly increased MSCA-1 levels under PL cultivation. While JPCs only occasionally mineralize under FCS culture conditions, the mineralization potential was significantly stronger under PL cultivation. Moreover, in 4 of 5 analyzed patient cells, the addition of dexamethasone was proved no longer necessary for strong mineralization of PL-cultured JPCs. We conclude that in vitro cultivation of JPCs with platelet lysate is a suitable alternative to FCS culture conditions and a powerful tool for the development of high-quality TE constructs using jaw periosteal cells. PMID:29391870
The role of the PI3K-Akt signaling pathway in the developmental competence of bovine oocytes.

PubMed

Andrade, Gabriella Mamede; da Silveira, Juliano Coelho; Perrini, Claudia; Del Collado, Maite; Gebremedhn, Samuel; Tesfaye, Dawit; Meirelles, Flávio Vieira; Perecin, Felipe

2017-01-01

The ovarian follicle encloses oocytes in a microenvironment throughout their growth and acquisition of competence. Evidence suggests a dynamic interplay among follicular cells and oocytes, since they are constantly exchanging "messages". We dissected bovine ovarian follicles and recovered follicular cells (FCs-granulosa and cumulus cells) and cumulus-oocyte complexes (COCs) to investigate whether the PI3K-Akt signaling pathway impacted oocyte quality. Following follicle rupture, COCs were individually selected for in vitro cultures to track the follicular cells based on oocyte competence to reach the blastocyst stage after parthenogenetic activation. Levels of PI3K-Akt signaling pathway components in FCs correlated with oocyte competence. This pathway is upregulated in FCs from follicles with high-quality oocytes that are able to reach the blastocyst stage, as indicated by decreased levels of PTEN and increased levels of the PTEN regulators bta-miR-494 and bta-miR-20a. Using PI3K-Akt responsive genes, we showed decreased FOXO3a levels and BAX levels in lower quality groups, indicating changes in cell cycle progression, oxidative response and apoptosis. Based on these results, the measurement of levels of PI3K-Akt pathway components in FCs from ovarian follicles carrying oocytes with distinct developmental competences is a useful tool to identify putative molecular pathways involved in the acquisition of oocyte competence.
Clinical-grade mesenchymal stromal cells produced under various good manufacturing practice processes differ in their immunomodulatory properties: standardization of immune quality controls.

PubMed

Menard, Cedric; Pacelli, Luciano; Bassi, Giulio; Dulong, Joelle; Bifari, Francesco; Bezier, Isabelle; Zanoncello, Jasmina; Ricciardi, Mario; Latour, Maelle; Bourin, Philippe; Schrezenmeier, Hubert; Sensebé, Luc; Tarte, Karin; Krampera, Mauro

2013-06-15

Clinical-grade mesenchymal stromal cells (MSCs) are usually expanded from bone marrow (BMMSCs) or adipose tissue (ADSCs) using processes mainly differing in the use of fetal calf serum (FCS) or human platelet lysate (PL). We aimed to compare immune modulatory properties of clinical-grade MSCs using a combination of fully standardized in vitro assays. BMMSCs expanded with FCS (BMMSC-FCS) or PL (BMMSC-PL), and ADSC-PL were analyzed in quantitative phenotypic and functional experiments, including their capacity to inhibit the proliferation of T, B, and NK cells. The molecular mechanisms supporting T-cell inhibition were investigated. These parameters were also evaluated after pre-stimulation of MSCs with inflammatory cytokines. BMMSC-FCS, BMMSC-PL, and ADSC-PL displayed significant differences in expression of immunosuppressive and adhesion molecules. Standardized functional assays revealed that resting MSCs inhibited proliferation of T and NK cells, but not B cells. ADSC-PL were the most potent in inhibiting T-cell growth, a property ascribed to interferon-γ-dependent indoleamine 2,3-dioxygenase activity. MSCs did not stimulate allogeneic T cell proliferation but were efficiently lysed by activated NK cells. The systematic use of quantitative and reproducible validation techniques highlights differences in immunological properties of MSCs produced using various clinical-grade processes. ADSC-PL emerge as a promising candidate for future clinical trials.
Orion Entry Flight Control Stability and Performance

NASA Technical Reports Server (NTRS)

Strahan, Alan L.; Loe, Greg R.; Seiler, Pete

2007-01-01

The Orion Spacecraft will be required to perform entry and landing functions for both Low Earth Orbit (LEO) and Lunar return missions, utilizing only the Command Module (CM) with its unique systems and GN&C design. This paper presents the current CM Flight Control System (FCS) design to support entry and landing, with a focus on analyses that have supported its development to date. The CM FCS will have to provide for spacecraft stability and control while following guidance or manual commands during exo-atmospheric flight, after Service Module separation, translational powered flight required of the CM, atmospheric flight supporting both direct entry and skip trajectories down to drogue chute deploy, and during roll attitude reorientation just prior to touchdown. Various studies and analyses have been performed or are on-going supporting an overall FCS design with reasonably sized Reaction Control System (RCS) jets, that minimizes fuel usage, that provides appropriate command following but with reasonable stability and control margin. Results from these efforts to date are included, with particular attention on design issues that have emerged, such as the struggle to accommodate sub-sonic pitch and yaw control without using excessively large jets that could have a detrimental impact on vehicle weight. Apollo, with a similar shape, struggled with this issue as well. Outstanding CM FCS related design and analysis issues, planned for future effort, are also briefly be discussed.
Studies on the formation and stability of triplex DNA using fluorescence correlation spectroscopy.

PubMed

Hu, Hongyan; Huang, Xiangyi; Ren, Jicun

2016-05-01

Triplex DNA has become one of the most useful recognition motifs in the design of new molecular biology tools, therapeutic agents and sophisticated DNA-based nanomaterials because of its direct recognition of natural double-stranded DNA. In this paper, we developed a sensitive and microscale method to study the formation and stability characterization of triplex DNA using fluorescence correlation spectroscopy (FCS). The principle of this method is mainly based on the excellent capacity of FCS for sensitively distinguishing between free single-strand DNA (ssDNA) fluorescent probes and fluorescent probe-double-strand DNA (dsDNA) hybridized complexes. First, we systematically investigated the experimental conditions of triplex DNA formation. Then, we evaluated the equilibrium association constants (K(a)) under different ssDNA probe lengths, composition and pH. Finally, we used FCS to measure the hybridization fraction of a 20-mer perfectly matched ssDNA probe and three single-base mismatched ssDNA probes with 146-mer dsDNA. Our data illustrated that FCS is a useful tool for the direct determination of the thermodynamic parameters of triplex DNA formation and discrimination of a single-base mismatch of triplex DNA without denaturation. Compared with current methods, our method is characterized by high sensitivity, good universality and small sample and reagent requirements. More importantly, our method has the potential to become a platform for triplex DNA research in vitro. Copyright © 2015 John Wiley & Sons, Ltd.
Clinical-Grade Mesenchymal Stromal Cells Produced Under Various Good Manufacturing Practice Processes Differ in Their Immunomodulatory Properties: Standardization of Immune Quality Controls

PubMed Central

Menard, Cedric; Pacelli, Luciano; Bassi, Giulio; Dulong, Joelle; Bifari, Francesco; Bezier, Isabelle; Zanoncello, Jasmina; Ricciardi, Mario; Latour, Maelle; Bourin, Philippe; Schrezenmeier, Hubert; Sensebé, Luc

2013-01-01

Clinical-grade mesenchymal stromal cells (MSCs) are usually expanded from bone marrow (BMMSCs) or adipose tissue (ADSCs) using processes mainly differing in the use of fetal calf serum (FCS) or human platelet lysate (PL). We aimed to compare immune modulatory properties of clinical-grade MSCs using a combination of fully standardized in vitro assays. BMMSCs expanded with FCS (BMMSC-FCS) or PL (BMMSC-PL), and ADSC-PL were analyzed in quantitative phenotypic and functional experiments, including their capacity to inhibit the proliferation of T, B, and NK cells. The molecular mechanisms supporting T-cell inhibition were investigated. These parameters were also evaluated after pre-stimulation of MSCs with inflammatory cytokines. BMMSC-FCS, BMMSC-PL, and ADSC-PL displayed significant differences in expression of immunosuppressive and adhesion molecules. Standardized functional assays revealed that resting MSCs inhibited proliferation of T and NK cells, but not B cells. ADSC-PL were the most potent in inhibiting T-cell growth, a property ascribed to interferon-γ-dependent indoleamine 2,3-dioxygenase activity. MSCs did not stimulate allogeneic T cell proliferation but were efficiently lysed by activated NK cells. The systematic use of quantitative and reproducible validation techniques highlights differences in immunological properties of MSCs produced using various clinical-grade processes. ADSC-PL emerge as a promising candidate for future clinical trials. PMID:23339531
Culture of preimplantation mouse embryos affects fetal development and the expression of imprinted genes.

PubMed

Khosla, S; Dean, W; Brown, D; Reik, W; Feil, R

2001-03-01

Culture of preimplantation mammalian embryos and cells can influence their subsequent growth and differentiation. Previously, we reported that culture of mouse embryonic stem cells is associated with deregulation of genomic imprinting and affects the potential for these cells to develop into normal fetuses. The purpose of our current study was to determine whether culture of preimplantation mouse embryos in a chemically defined medium (M16) with or without fetal calf serum (FCS) can affect their subsequent development and imprinted gene expression. Only one third of the blastocysts that had been cultured from two-cell embryos in M16 medium complemented with FCS developed into viable Day 14 fetuses after transfer into recipients. These M16 + FCS fetuses were reduced in weight as compared with controls and M16 fetuses and had decreased expression of the imprinted H19 and insulin-like growth factor 2 genes associated with a gain of DNA methylation at an imprinting control region upstream of H19. They also displayed increased expression of the imprinted gene Grb10. The growth factor receptor binding gene Grb7, in contrast, was strongly reduced in its expression in most of the M16 + FCS fetuses. No alterations were detected for the imprinted gene MEST: Preimplantation culture in the presence of serum can influence the regulation of multiple growth-related imprinted genes, thus leading to aberrant fetal growth and development.
Assessment of Knowledge of Critical Cardiovascular Risk Indicators among College Students: Does Stage of Education Matter?

PubMed Central

Sarpong, Daniel F.; Curry, India Y.; Williams, Melinda

2017-01-01

The health risk of college students in the United States (US) is on the rise, with a significant increase in the prevalence of cardiovascular risk factors. Cardiovascular disease is the leading cause of death in the US, costing approximately $475.3 billion yearly. The goals of this “Know Your Numbers” study were to: (1) estimate the awareness of college students of their critical health numbers (CHN); and (2) compare a college of pharmacy entry class (IP1) with second semester non-commuter freshman college students (FCS) in knowing their numbers. A cross-sectional 15-item pre-test survey was conducted among a convenience sample of IP1 and FCS. All statistical tests were performed at α = 0.05. Awareness of their: cholesterol (7%), blood pressure (BP) (35%), glucose (8%), and body mass index (BMI) (42%) were low. The IP1, compared to FCS, were more knowledgeable of: (1) their BP (46% vs. 28%, p = 0.01); (2) BP normal range (74% vs. 63%, p = 0.02); and (3) BMI normal range (39% vs. 23%, p = 0.04). The IP1s maintained a healthier diet than the FCS (64% vs. 36%, p < 0.0001). Awareness of knowing CHN was very low. Knowledge of one’s CHN was significantly associated with knowledge of normal reference values for BP, glucose, and BMI. PMID:28257080
Biobanking of patient and patient-derived xenograft ovarian tumour tissue: efficient preservation with low and high fetal calf serum based methods.

PubMed

Alkema, Nicolette G; Tomar, Tushar; Duiker, Evelien W; Jan Meersma, Gert; Klip, Harry; van der Zee, Ate G J; Wisman, G Bea A; de Jong, Steven

2015-10-06

Using patient-derived xenografts (PDXs) for preclinical cancer research demands proper storage of tumour material to facilitate logistics and to reduce the number of animals needed. We successfully established 45 subcutaneous ovarian cancer PDXs, reflecting all histological subtypes, with an overall take rate of 68%. Corresponding cells from mouse replaced human tumour stromal and endothelial cells in second generation PDXs as demonstrated with mouse-specific vimentin and CD31 immunohistochemical staining. For biobanking purposes two cryopreservation methods, a fetal calf serum (FCS)-based (95%v/v) "FCS/DMSO" protocol and a low serum-based (10%v/v) "vitrification" protocol were tested. After primary cryopreservation, tumour take rates were 38% and 67% using either the vitrification or FCS/DMSO-based cryopreservation protocol, respectively. Cryopreserved tumour tissue of established PDXs achieved take rates of 67% and 94%, respectively compared to 91% using fresh PDX tumour tissue. Genotyping analysis showed that no changes in copy number alterations were introduced by any of the biobanking methods. Our results indicate that both protocols can be used for biobanking of ovarian tumour and PDX tissues. However, FCS/DMSO-based cryopreservation is more successful. Moreover, primary engraftment of fresh patient-derived tumours in mice followed by freezing tissue of successfully established PDXs is the preferred way of efficient ovarian cancer PDX biobanking.
Institutions, Politics, and Mental Health Parity

PubMed Central

Hernandez, Elaine M.; Uggen, Christopher

2013-01-01

Mental health parity laws require insurers to extend comparable benefits for mental and physical health care. Proponents argue that by placing mental health services alongside physical health services, such laws can help ensure needed treatment and destigmatize mental illness. Opponents counter that such mandates are costly or unnecessary. The authors offer a sociological account of the diffusion and spatial distribution of state mental health parity laws. An event history analysis identifies four factors as especially important: diffusion of law, political ideology, the stability of mental health advocacy organizations and the relative health of state economies. Mental health parity is least likely to be established during times of high state unemployment and under the leadership of conservative state legislatures. PMID:24353902
Passive scalars: Mixing, diffusion, and intermittency in helical and nonhelical rotating turbulence

NASA Astrophysics Data System (ADS)

Imazio, P. Rodriguez; Mininni, P. D.

2017-03-01

We use direct numerical simulations to compute structure functions, scaling exponents, probability density functions, and effective transport coefficients of passive scalars in turbulent rotating helical and nonhelical flows. We show that helicity affects the inertial range scaling of the velocity and of the passive scalar when rotation is present, with a spectral law consistent with ˜k⊥-1.4 for the passive scalar variance spectrum. This scaling law is consistent with a phenomenological argument [P. Rodriguez Imazio and P. D. Mininni, Phys. Rev. E 83, 066309 (2011), 10.1103/PhysRevE.83.066309] for rotating nonhelical flows, which follows directly from Kolmogorov-Obukhov scaling and states that if energy follows a E (k ) ˜k-n law, then the passive scalar variance follows a law V (k ) ˜k-nθ with nθ=(5 -n ) /2 . With the second-order scaling exponent obtained from this law, and using the Kraichnan model, we obtain anomalous scaling exponents for the passive scalar that are in good agreement with the numerical results. Multifractal intermittency models are also considered. Intermittency of the passive scalar is stronger than in the nonhelical rotating case, a result that is also confirmed by stronger non-Gaussian tails in the probability density functions of field increments. Finally, Fick's law is used to compute the effective diffusion coefficients in the directions parallel and perpendicular to rotation. Calculations indicate that horizontal diffusion decreases in the presence of helicity in rotating flows, while vertical diffusion increases. A simple mean field argument explains this behavior in terms of the amplitude of velocity fluctuations.
ATP and magnesium promote cotton short-form ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase hexamer formation at low micromolar concentrations.

PubMed

Kuriata, Agnieszka M; Chakraborty, Manas; Henderson, J Nathan; Hazra, Suratna; Serban, Andrew J; Pham, Tuong V T; Levitus, Marcia; Wachter, Rebekka M

2014-11-25

We report a fluorescence correlation spectroscopy (FCS) study of the assembly pathway of the AAA+ protein ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase (Rca), a ring-forming ATPase responsible for activation of inhibited Rubisco complexes for biological carbon fixation. A thermodynamic characterization of simultaneously populated oligomeric states appears critical in understanding Rca structure and function. Using cotton β-Rca, we demonstrate that apparent diffusion coefficients vary as a function of concentration, nucleotide, and cation. Using manual fitting procedures, we provide estimates for the equilibrium constants for the stepwise assembly and find that in the presence of ATPγS, the Kd for hexamerization is 10-fold lower than with ADP (∼0.1 vs ∼1 μM). Hexamer fractions peak at 30 μM and dominate at 8-70 μM Rca, where they comprise 60-80% of subunits with ATPγS, compared with just 30-40% with ADP. Dimer fractions peak at 1-4 μM Rca, where they comprise 15-18% with ATPγS and 26-28% with ADP. At 30 μM Rca, large aggregates begin to form that comprise ∼10% of total protein with ATPγS and ∼25% with ADP. FCS data collected on the catalytically impaired WalkerB-D173N variant in the presence of ATP provided strong support for these results. Titration with free magnesium ions lead to the disaggregation of larger complexes in favor of hexameric forms, suggesting that a second magnesium binding site with a Kd value of 1-3 mM mediates critical subunit contacts. We propose that closed-ring toroidal hexameric forms are stabilized by binding of Mg·ATP plus Mg2+, whereas Mg·ADP promotes continuous assembly to supramolecular aggregates such as spirals.
Silent strain of caregiving: exploring the best predictors of distress in family carers of geriatric patients.

PubMed

Bień-Barkowska, Katarzyna; Doroszkiewicz, Halina; Bień, Barbara

2017-01-01

The aim of this article was to identify the best predictors of distress suffered by family carers (FCs) of geriatric patients. A cross-sectional study of 100 FC-geriatric patient dyads was conducted. The negative impact of care (NIoC) subscale of the COPE index was dichotomized to identify lower stress (score of ≤15 on the scale) and higher stress (score of ≥16 on the scale) exerted on FCs by the process of providing care. The set of explanatory variables comprised a wide range of sociodemographic and care-related attributes, including patient-related results from comprehensive geriatric assessments and disease profiles. The best combination of explanatory variables that provided the highest predictive power for distress among FCs in the multiple logistic regression (LR) model was determined according to statistical information criteria. The statistical robustness of the observed relationships and the discriminative power of the model were verified with the cross-validation method. The mean age of FCs was 57.2 (±10.6) years, whereas that of geriatric patients was 81.7 (±6.4) years. Despite the broad initial set of potential explanatory variables, only five predictors were jointly selected for the best statistical model. A higher level of distress was independently predicted by lower self-evaluation of health; worse self-appraisal of coping well as a caregiver; lower sense of general support; more hours of care per week; and the motor retardation of the cared-for person measured with the speed of the Timed Up and Go (TUG) test. Worse performance on the TUG test was only the patient-related predictor of distress among the variables examined as contributors to the higher NIoC. Enhancing the mobility of geriatric patients through suitably tailored kinesitherapeutic methods during their hospital stay may mitigate the burden endured by FCs.
A systematic review of the effectiveness of flipped classrooms in medical education.

PubMed

Chen, Fei; Lui, Angela M; Martinelli, Susan M

2017-06-01

There are inconsistent claims made about the effectiveness of the flipped classroom (FC) in medical education; however, the quality of the empirical evidence used to back up these claims is not evident. The aims of this review are to examine the scope and quality of studies on the FC teaching approach in medical education and to assess the effects of FCs on medical learning. A literature search was conducted using the major electronic databases in 2016. Peer-reviewed papers were screened and reviewed according to explicit inclusion criteria. The scope and quality of all resultant studies were evaluated. Studies identified as using controlled designs were further synthesised to assess the effects of FCs on learning. A total of 118 articles were obtained. Full texts of 82 articles were reviewed. Nine of the included 46 articles used a controlled design when examining the effects of the FC. There were generally positive perceptions of the FC approach. However, the effects of FCs on changes in knowledge and skills were less conclusive as the effect sizes ranged from d = -0.27 to 1.21, with a median of 0.08. The varying direction and magnitude of the effect sizes, together with their 95% confidence interval, which contained zero, suggested the lack of strong evidence for the effectiveness of FCs in promoting knowledge acquisition above and beyond the traditional learning methods. There has been a recent increase of research rigor and variety in measures of effectiveness in studies on the FC in medical education. The FC is a promising teaching approach to increase learners' motivation and engagement. More solid evidence on its effect on changes in knowledge and skills are warranted. Further studies should also examine the long-term effects of FCs with regard to knowledge retention and transfer of knowledge to professional practice and patient care. © 2017 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

Supporting Evidence for the Astronomically Calibrated Age of Fish Canyon Sanidine

NASA Astrophysics Data System (ADS)

Rivera, T. A.; Storey, M.; Zeeden, C.; Kuiper, K.; Hilgen, F.

2010-12-01

The relative nature of the 40Ar/39Ar radio-isotopic dating technique requires that the age and error of the monitor mineral be accurately known. The most widely accepted monitor for Cenozoic geochronology is the Fish Canyon sanidine (FCs), whose recommended published ages have varied by up to 2% over the past two decades. To reconcile the discrepancy among recommended ages, researchers have turned to the use of (i) intercalibration experiments with primary argon standards, (ii) cross-calibration with U-Pb ages, and (iii) cross-calibration with sanidine-hosted tephras present in astronomically tuned stratigraphic sections. The increasingly robust quality of the astronomical timescale, with precision better than 0.1% for the last 10 million years, suggests this method of intercalibration as the best way to proceed with addressing the true age of FCs. Recently, Kuiper, et al. (2008) determined an astronomically calibrated age of 28.201 ± 0.046 Ma (2σ), based upon the Moroccan Melilla Basin Messâdit section. Here, we provide independent verification for the Kuiper, et al. (2008) FCs age using sanidines extracted from a tephra intercalated in another Mediterranean-based astronomically tuned section. The direct tuning of this section was achieved through correlation to long (~400 kyr) and short (~100 kyr) eccentricity, followed by tuning of basic sedimentary cycles to precession and summer insolation, using the La2004(1,1) astronomical solution (Laskar, et al., 2004). We employed a Nu Instruments Noblesse multi-collector noble gas mass spectrometer for the 40Ar/39Ar experiments, analyzing single crystals of FCs relative to sanidines from the astronomically dated tephra. The use of the multi-collector instrument allowed us to obtain high precision analyses with a level of precision for fully propagated external errors for FCs near the 0.1% goal of EARTHTIME. The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 215458.
Nucleolar sub-compartments in motion during rRNA synthesis inhibition: Contraction of nucleolar condensed chromatin and gathering of fibrillar centers are concomitant

PubMed Central

Tchelidze, Pavel; Benassarou, Aassif; Kaplan, Hervé; O’Donohue, Marie-Françoise; Lucas, Laurent; Terryn, Christine; Rusishvili, Levan; Mosidze, Giorgi; Lalun, Nathalie

2017-01-01

The nucleolus produces the large polycistronic transcript (47S precursor) containing the 18S, 5.8S and 28S rRNA sequences and hosts most of the nuclear steps of pre-rRNA processing. Among numerous components it contains condensed chromatin and active rRNA genes which adopt a more accessible conformation. For this reason, it is a paradigm of chromosome territory organization. Active rRNA genes are clustered within several fibrillar centers (FCs), in which they are maintained in an open configuration by Upstream Binding Factor (UBF) molecules. Here, we used the reproducible reorganization of nucleolar components induced by the inhibition of rRNA synthesis by Actinomycin D (AMD) to address the steps of the spatiotemporal reorganization of FCs and nucleolar condensed chromatin. To reach that goal, we used two complementary approaches: i) time-lapse confocal imaging of cells expressing one or several GFP-tagged proteins (fibrillarin, UBF, histone H2B) and ii) ultrastructural identification of nucleolar components involved in the reorganization. Data obtained by time lapse confocal microscopy were analyzed through detailed 3D imaging. This allowed us to demonstrate that AMD treatment induces no fusion and no change in the relative position of the different nucleoli contained in one nucleus. In contrast, for each nucleolus, we observed step by step gathering and fusion of both FCs and nucleolar condensed chromatin. To analyze the reorganization of FCs and condensed chromatin at a higher resolution, we performed correlative light and electron microscopy electron microscopy (CLEM) imaging of the same cells. We demonstrated that threads of intranucleolar condensed chromatin are localized in a complex 3D network of vacuoles. Upon AMD treatment, these structures coalesce before migrating toward the perinucleolar condensed chromatin, to which they finally fuse. During their migration, FCs, which are all linked to ICC, are pulled by the latter to gather as caps disposed at the periphery of nucleoli. PMID:29190286
Gender differences in functional connectivities between insular subdivisions and selective pain-related brain structures.

PubMed

Dai, Yu-Jie; Zhang, Xin; Yang, Yang; Nan, Hai-Yan; Yu, Ying; Sun, Qian; Yan, Lin-Feng; Hu, Bo; Zhang, Jin; Qiu, Zi-Yu; Gao, Yi; Cui, Guang-Bin; Chen, Bi-Liang; Wang, Wen

2018-03-14

The incidence of pain disorders in women is higher than in men, making gender differences in pain a research focus. The human insular cortex is an important brain hub structure for pain processing and is divided into several subdivisions, serving different functions in pain perception. Here we aimed to examine the gender differences of the functional connectivities (FCs) between the twelve insular subdivisions and selected pain-related brain structures in healthy adults. Twenty-six healthy males and 11 age-matched healthy females were recruited in this cross-sectional study. FCs between the 12 insular subdivisions (as 12 regions of interest (ROIs)) and the whole brain (ROI-whole brain level) or 64 selected pain-related brain regions (64 ROIs, ROI-ROI level) were measured between the males and females. Significant gender differences in the FCs of the insular subdivisions were revealed: (1) The FCs between the dorsal dysgranular insula (dId) and other brain regions were significantly increased in males using two different techniques (ROI-whole brain and ROI-ROI analyses); (2) Based on the ROI-whole brain analysis, the FC increases in 4 FC-pairs were observed in males, including the left dId - the right median cingulate and paracingulate/ right posterior cingulate gyrus/ right precuneus, the left dId - the right median cingulate and paracingulate, the left dId - the left angular as well as the left dId - the left middle frontal gyrus; (3) According to the ROI-ROI analysis, increased FC between the left dId and the right rostral anterior cingulate cortex was investigated in males. In summary, the gender differences in the FCs of the insular subdivisions with pain-related brain regions were revealed in the current study, offering neuroimaging evidence for gender differences in pain processing. ClinicalTrials.gov, NCT02820974 . Registered 28 June 2016.
Can specially trained community care workers effectively support patients and their families in the home setting at the end of life?

PubMed

Poulos, Roslyn G; Harkin, Damian; Poulos, Christopher J; Cole, Andrew; MacLeod, Rod

2018-03-01

Surveys indicate that many Australians would prefer to die at home, but relatively few do. Recognising that patients and their families may not have the support they need to enable end-of-life care at home, a consortium of care providers developed, and received funding to trial, the Palliative Care Home Support Program (PCHSP) across seven health districts in New South Wales, Australia. The programme aimed to supplement end-of-life care in the home provided by existing multidisciplinary community palliative care teams, with specialist supportive community care workers (CCWs). An evaluation of the service was undertaken, focussing on the self-reported impact of the service on family carers (FCs), with triangulation of findings from community palliative care teams and CCWs. Service evaluation data were obtained through postal surveys and/or qualitative interviews with FCs, community palliative care teams and CCWs. FCs also reported the experience of their loved one based on 10 items drawn from the Quality of Death and Dying Questionnaire (QODD). Thematic analysis of surveys and interviews found that the support provided by CCWs was valued by FCs for: enabling choice (i.e. to realise end-of-life care in the home); providing practical assistance ("hands-on"); and for emotional support and reassurance. This was corroborated by community palliative care teams and CCWs. Responses by FCs on the QODD items indicated that in the last week of life, effective control of symptoms was occurring and quality of life was being maintained. This study suggests that satisfactory outcomes for patients and their families who wish to have end-of-life care in the home can be enabled with the additional support of specially trained CCWs. A notable benefit of the PCHSP model, which provided specific palliative care vocational training to an existing community care workforce, was a relatively rapid increase in the palliative care workforce across the state. © 2017 John Wiley & Sons Ltd.
PyCorrFit-generic data evaluation for fluorescence correlation spectroscopy.

PubMed

Müller, Paul; Schwille, Petra; Weidemann, Thomas

2014-09-01

We present a graphical user interface (PyCorrFit) for the fitting of theoretical model functions to experimental data obtained by fluorescence correlation spectroscopy (FCS). The program supports many data file formats and features a set of tools specialized in FCS data evaluation. The Python source code is freely available for download from the PyCorrFit web page at http://pycorrfit.craban.de. We offer binaries for Ubuntu Linux, Mac OS X and Microsoft Windows. © The Author 2014. Published by Oxford University Press.
External Factors, Produced by Growing Nerves, Trigger a Regenerative Response in a Non-Regenerative Central Nervous System: Purification and Mode of Action

DTIC Science & Technology

1989-06-01

regenerating optic nerve CNS - Central nervous system FCS - Fetal calf serum Galc - Galactocerebroside G AP - Glial fibriliary acidic protein NGF...nent confinment of the casualty to a wheel chair. Laceration in the upper spinal cord leads to paralysis of the four limbs and a cut in the optic...of microtiter plates in Dulbecco’s modified Eagle medium (DVIEM) containing 10% fetal calf serum (FCS). When the cells reached confluency the medium
Evolving fuzzy rules in a learning classifier system

NASA Technical Reports Server (NTRS)

Valenzuela-Rendon, Manuel

1993-01-01

The fuzzy classifier system (FCS) combines the ideas of fuzzy logic controllers (FLC's) and learning classifier systems (LCS's). It brings together the expressive powers of fuzzy logic as it has been applied in fuzzy controllers to express relations between continuous variables, and the ability of LCS's to evolve co-adapted sets of rules. The goal of the FCS is to develop a rule-based system capable of learning in a reinforcement regime, and that can potentially be used for process control.
Design Loads for Future Aircraft (Les Charges de Calcul Pour de Futurs Aeronefs)

DTIC Science & Technology

2002-02-01

brake attachment bolt you first have to remove both ejection seats and the actuator cover that is located between the right position rudder pedals . Since...continuous turbulence and inclusion of FCS failure cases and nonlinearities such as control surface angles is extremely important. There was a long way...FCS) et des non-linéarités, tels que les angles de gouverne, sont extrêmement importantes. Un long chemin sépare les hypothèses de charge
A Study of the Concept and Implementation of the Lead Systems Integrator in Defense Acquisitions

DTIC Science & Technology

2007-12-01

equips itself to fight U.S. adversaries. The Army has recognized that it needs to transform itself to conduct “full spectrum operations” ( Fetterman and...mountains and jungles” ( Fetterman and Plushnik 2). The Army describes the program as the most complex acquisition in its history because it involves...considered to be two additional systems; thus, it is dubbed “14+1+1” ( Fetterman ). Figure 1 shows all the systems in the FCS. 21 Figure 1. FCS Systems
Simple scaling laws for the evaporation of droplets pinned on pillars: Transfer-rate- and diffusion-limited regimes.

PubMed

Hernandez-Perez, Ruth; García-Cordero, José L; Escobar, Juan V

2017-12-01

The evaporation of droplets can give rise to a wide range of interesting phenomena in which the dynamics of the evaporation are crucial. In this work, we find simple scaling laws for the evaporation dynamics of axisymmetric droplets pinned on millimeter-sized pillars. Different laws are found depending on whether evaporation is limited by the diffusion of vapor molecules or by the transfer rate across the liquid-vapor interface. For the diffusion-limited regime, we find that a mass-loss rate equal to 3/7 of that of a free-standing evaporating droplet brings a good balance between simplicity and physical correctness. We also find a scaling law for the evaporation of multicomponent solutions. The scaling laws found are validated against experiments of the evaporation of droplets of (1) water, (2) blood plasma, and (3) a mixture of water and polyethylene glycol, pinned on acrylic pillars of different diameters. These results shed light on the macroscopic dynamics of evaporation on pillars as a first step towards the understanding of other complex phenomena that may be taking place during the evaporation process, such as particle transport and chemical reactions.
Simple scaling laws for the evaporation of droplets pinned on pillars: Transfer-rate- and diffusion-limited regimes

NASA Astrophysics Data System (ADS)

Hernandez-Perez, Ruth; García-Cordero, José L.; Escobar, Juan V.

2017-12-01

The evaporation of droplets can give rise to a wide range of interesting phenomena in which the dynamics of the evaporation are crucial. In this work, we find simple scaling laws for the evaporation dynamics of axisymmetric droplets pinned on millimeter-sized pillars. Different laws are found depending on whether evaporation is limited by the diffusion of vapor molecules or by the transfer rate across the liquid-vapor interface. For the diffusion-limited regime, we find that a mass-loss rate equal to 3/7 of that of a free-standing evaporating droplet brings a good balance between simplicity and physical correctness. We also find a scaling law for the evaporation of multicomponent solutions. The scaling laws found are validated against experiments of the evaporation of droplets of (1) water, (2) blood plasma, and (3) a mixture of water and polyethylene glycol, pinned on acrylic pillars of different diameters. These results shed light on the macroscopic dynamics of evaporation on pillars as a first step towards the understanding of other complex phenomena that may be taking place during the evaporation process, such as particle transport and chemical reactions.
Modified Beer-Lambert law for blood flow

PubMed Central

Baker, Wesley B.; Parthasarathy, Ashwin B.; Busch, David R.; Mesquita, Rickson C.; Greenberg, Joel H.; Yodh, A. G.

2014-01-01

We develop and validate a Modified Beer-Lambert law for blood flow based on diffuse correlation spectroscopy (DCS) measurements. The new formulation enables blood flow monitoring from temporal intensity autocorrelation function data taken at single or multiple delay-times. Consequentially, the speed of the optical blood flow measurement can be substantially increased. The scheme facilitates blood flow monitoring of highly scattering tissues in geometries wherein light propagation is diffusive or non-diffusive, and it is particularly well-suited for utilization with pressure measurement paradigms that employ differential flow signals to reduce contributions of superficial tissues. PMID:25426330
Scaling Law for Cross-stream Diffusion in Microchannels under Combined Electroosmotic and Pressure Driven Flow.

PubMed

Song, Hongjun; Wang, Yi; Pant, Kapil

2013-01-01

This paper presents an analytical study of the cross-stream diffusion of an analyte in a rectangular microchannel under combined electroosmotic flow (EOF) and pressure driven flow to investigate the heterogeneous transport behavior and spatially-dependent diffusion scaling law. An analytical model capable of accurately describing 3D steady-state convection-diffusion in microchannels with arbitrary aspect ratios is developed based on the assumption of the thin Electric Double Layer (EDL). The model is verified against high-fidelity numerical simulation in terms of flow velocity and analyte concentration profiles with excellent agreement (<0.5% relative error). An extensive parametric analysis is then undertaken to interrogate the effect of the combined flow velocity field on the transport behavior in both the positive pressure gradient (PPG) and negative pressure gradient (NPG) cases. For the first time, the evolution from the spindle-shaped concentration profile in the PPG case, via the stripe-shaped profile (pure EOF), and finally to the butterfly-shaped profile in the PPG case is obtained using the analytical model along with a quantitative depiction of the spatially-dependent diffusion layer thickness and scaling law across a wide range of the parameter space.
Scaling Law for Cross-stream Diffusion in Microchannels under Combined Electroosmotic and Pressure Driven Flow

PubMed Central

Song, Hongjun; Wang, Yi; Pant, Kapil

2012-01-01

This paper presents an analytical study of the cross-stream diffusion of an analyte in a rectangular microchannel under combined electroosmotic flow (EOF) and pressure driven flow to investigate the heterogeneous transport behavior and spatially-dependent diffusion scaling law. An analytical model capable of accurately describing 3D steady-state convection-diffusion in microchannels with arbitrary aspect ratios is developed based on the assumption of the thin Electric Double Layer (EDL). The model is verified against high-fidelity numerical simulation in terms of flow velocity and analyte concentration profiles with excellent agreement (<0.5% relative error). An extensive parametric analysis is then undertaken to interrogate the effect of the combined flow velocity field on the transport behavior in both the positive pressure gradient (PPG) and negative pressure gradient (NPG) cases. For the first time, the evolution from the spindle-shaped concentration profile in the PPG case, via the stripe-shaped profile (pure EOF), and finally to the butterfly-shaped profile in the PPG case is obtained using the analytical model along with a quantitative depiction of the spatially-dependent diffusion layer thickness and scaling law across a wide range of the parameter space. PMID:23554584
An improved model of fission gas atom transport in irradiated uranium dioxide

NASA Astrophysics Data System (ADS)

Shea, J. H.

2018-04-01

The hitherto standard approach to predicting fission gas release has been a pure diffusion gas atom transport model based upon Fick's law. An additional mechanism has subsequently been identified from experimental data at high burnup and has been summarised in an empirical model that is considered to embody a so-called fuel matrix 'saturation' phenomenon whereby the fuel matrix has become saturated with fission gas so that the continued addition of extra fission gas atoms results in their expulsion from the fuel matrix into the fuel rod plenum. The present paper proposes a different approach by constructing an enhanced fission gas transport law consisting of two components: 1) Fick's law and 2) a so-called drift term. The new transport law can be shown to be effectively identical in its predictions to the 'saturation' approach and is more readily physically justifiable. The method introduces a generalisation of the standard diffusion equation which is dubbed the Drift Diffusion Equation. According to the magnitude of a dimensionless Péclet number, P, the new equation can vary from pure diffusion to pure drift, which latter represents a collective motion of the fission gas atoms through the fuel matrix at a translational velocity. Comparison is made between the saturation and enhanced transport approaches. Because of its dependence on P, the Drift Diffusion Equation is shown to be more effective at managing the transition from one type of limiting transport phenomenon to the other. Thus it can adapt appropriately according to the reactor operation.
Understanding diffusion theory and Fick's law through food and cooking.

PubMed

Zhou, Larissa; Nyberg, Kendra; Rowat, Amy C

2015-09-01

Diffusion is critical to physiological processes ranging from gas exchange across alveoli to transport within individual cells. In the classroom, however, it can be challenging to convey the concept of diffusion on the microscopic scale. In this article, we present a series of three exercises that use food and cooking to illustrate diffusion theory and Fick's first law. These exercises are part of a 10-wk undergraduate course that uses food and cooking to teach fundamental concepts in physiology and biophysics to students, including nonscience majors. Consistent demonstration of practical applications in a classroom setting has the potential to fundamentally change how students view the role of science in their lives (15). Copyright © 2015 The American Physiological Society.
Modelling results for the thermal management sub-system of a combined heat and power (CHP) fuel cell system (FCS)

NASA Astrophysics Data System (ADS)

Colella, Whitney G.

Although the fuel cells research and development community has traditionally focused the majority of its efforts on improving the fuel cell stack's voltage (electrical efficiency), combined heat and power (CHP) fuel cell system (FCSs) may achieve a competitive advantage over conventional generators only if the research and development community refocuses its efforts on cultivating other inherent technical qualities of such systems. Based on an analysis of their use within energy markets, these inherent qualities include (1) an ability to vary their electrical load rapidly, (2) an ability to vary their heat to power ratio during operation, and (3) an ability to deliver their waste heat to a useful thermal sink. This article focuses on the last of three design objectives: effectively capturing heat from a CHP FCS. This article (1) delineates the design specifications for a 6 kWe CHP FCS, (2) analyses four possible cooling loop configurations for this system, and (3) concludes which one of these provides the optimal heat recovery performance.
Inexpensive electronics and software for photon statistics and correlation spectroscopy.

PubMed

Gamari, Benjamin D; Zhang, Dianwen; Buckman, Richard E; Milas, Peker; Denker, John S; Chen, Hui; Li, Hongmin; Goldner, Lori S

2014-07-01

Single-molecule-sensitive microscopy and spectroscopy are transforming biophysics and materials science laboratories. Techniques such as fluorescence correlation spectroscopy (FCS) and single-molecule sensitive fluorescence resonance energy transfer (FRET) are now commonly available in research laboratories but are as yet infrequently available in teaching laboratories. We describe inexpensive electronics and open-source software that bridges this gap, making state-of-the-art research capabilities accessible to undergraduates interested in biophysics. We include a discussion of the intensity correlation function relevant to FCS and how it can be determined from photon arrival times. We demonstrate the system with a measurement of the hydrodynamic radius of a protein using FCS that is suitable for the undergraduate teaching laboratory. The FPGA-based electronics, which are easy to construct, are suitable for more advanced measurements as well, and several applications are described. As implemented, the system has 8 ns timing resolution, can control up to four laser sources, and can collect information from as many as four photon-counting detectors.
Inexpensive electronics and software for photon statistics and correlation spectroscopy

PubMed Central

Gamari, Benjamin D.; Zhang, Dianwen; Buckman, Richard E.; Milas, Peker; Denker, John S.; Chen, Hui; Li, Hongmin; Goldner, Lori S.

2016-01-01

Single-molecule-sensitive microscopy and spectroscopy are transforming biophysics and materials science laboratories. Techniques such as fluorescence correlation spectroscopy (FCS) and single-molecule sensitive fluorescence resonance energy transfer (FRET) are now commonly available in research laboratories but are as yet infrequently available in teaching laboratories. We describe inexpensive electronics and open-source software that bridges this gap, making state-of-the-art research capabilities accessible to undergraduates interested in biophysics. We include a discussion of the intensity correlation function relevant to FCS and how it can be determined from photon arrival times. We demonstrate the system with a measurement of the hydrodynamic radius of a protein using FCS that is suitable for the undergraduate teaching laboratory. The FPGA-based electronics, which are easy to construct, are suitable for more advanced measurements as well, and several applications are described. As implemented, the system has 8 ns timing resolution, can control up to four laser sources, and can collect information from as many as four photon-counting detectors. PMID:26924846
Growth of erythroid burst-forming units (BFU-E) in cultures of canine bone marrow and peripheral blood cells: effect of serum from irradiated dogs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kreja, L.; Baltschukat, K.; Nothdurft, W.

1988-08-01

Erythroid burst-forming units (BFU-E) from canine bone marrow and peripheral blood could be grown in methylcellulose in the presence of an appropriate batch of fetal calf serum (FCS), transferrin, and erythropoietin (Epo). However, improved colony formation (size and number of bursts) was obtained when serum from total body irradiated dogs was present in the culture. This serum, obtained from dogs at day 9 after total body irradiation with a dose of 3.9 Gy, reduced markedly the Epo requirement of BFU-E. Furthermore, it allowed the omission of FCS from the culture medium if cholesterol and bovine serum albumin (BSA) were usedmore » as FCS substitutes. BFU-E concentrations were found to be rather different in the peripheral blood and in bone marrow samples from different sites (i.e., iliac crest, sternum, and humerus) of normal beagles. The studies further show that canine bone marrow BFU-E can be cryopreserved in liquid nitrogen.« less

STS-99 Shuttle Radar Topography Mission Stability and Control

NASA Technical Reports Server (NTRS)

Hamelin, Jennifer L.; Jackson, Mark C.; Kirchwey, Christopher B.; Pileggi, Roberto A.

2001-01-01

The Shuttle Radar Topography Mission (SRTM) flew aboard Space Shuttle Endeavor February 2000 and used interferometry to map 80% of the Earth's landmass. SRTM employed a 200-foot deployable mast structure to extend a second antenna away from the main antenna located in the Shuttle payload bay. Mapping requirements demanded precision pointing and orbital trajectories from the Shuttle on-orbit Flight Control System (PCS). Mast structural dynamics interaction with the FCS impacted stability and performance of the autopilot for attitude maneuvers and pointing during mapping operations. A damper system added to ensure that mast tip motion remained with in the limits of the outboard antenna tracking system while mapping also helped to mitigate structural dynamic interaction with the FCS autopilot. Late changes made to the payload damper system, which actually failed on-orbit, required a redesign and verification of the FCS autopilot filtering schemes necessary to ensure rotational control stability. In-flight measurements using three sensors were used to validate models and gauge the accuracy and robustness of the pre-mission notch filter design.
Common food colorants and allergic reactions in children: Myth or reality?

PubMed

Feketea, Gavriela; Tsabouri, Sophia

2017-09-01

Various additives, including food colorants (FCs), are used in the food industry to make food appealing to consumers and to add variety. Despite the widespread usage of FCs, adverse reactions related to their consumption, including reactions triggered by immune (immediate and delayed-type hypersensitivity) and non-immune (intolerance) mechanisms, are considered rare. There is a discrepancy between the perception of patients and parents (7.4%) and the reported prevalence of adverse reactions to additives (0.01-0.23%), which is higher in atopic individuals (2-7%). Documented reactions are mild, involving mainly the skin, and, rarely, anaphylaxis. A major problem in diagnosing reactions to FCs is identification of the offending agent(s), which is based on careful dietary history taking. Allergy testing is usually unrevealing, except for reaction to some natural colorants. Treatment consists of avoidance of the offending colorant as no successful desensitization procedures have been reported. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.
Evaluation of physiological, growth and yield responses of a tropical oil crop (Brassica campestris L. var. Kranti) under ambient ozone pollution at varying NPK levels.

PubMed

Singh, Poonam; Agrawal, Madhoolika; Agrawal, Shashi Bhushan

2009-03-01

A field study was conducted to evaluate the impact of ambient ozone on mustard (Brassica campestris L. var. Kranti) plants grown under recommended and 1.5 times recommended NPK doses at a rural site of India using filtered (FCs) and non-filtered open top chambers (NFCs). Ambient mean O(3) concentration varied from 41.65 to 54.2ppb during the experiment. Plants growing in FCs showed higher photosynthetic rate at both NPK levels, but higher stomatal conductance only at recommended NPK. There were improvements in growth parameters and biomass of plants in FCs as compared to NFCs at both NPK levels with higher increments at 1.5 times recommended. Seed yield and harvest index decreased significantly only at recommended NPK in NFCs. Seed quality in terms of nutrients, protein and oil contents reduced in NFCs at recommended NPK. The application of 1.5 times recommended NPK provided protection against yield loss due to ambient O(3).
Diffusion of liquid polystyrene into glassy poly(phenylene oxide) characterized by DSC

NASA Astrophysics Data System (ADS)

Li, Linling; Wang, Xiaoliang; Zhou, Dongshan; Xue, Gi

2013-03-01

We report a diffusion study on the polystyrene/poly(phenylene oxide) (PS/PPO) mixture consisted by the PS and PPO nanoparticles. Diffusion of liquid PS into glassy PPO (l-PS/g-PPO) is promoted by annealing the PS/PPO mixture at several temperatures below Tg of the PPO. By tracing the Tgs of the PS-rich domain behind the diffusion front using DSC, we get the relationships of PS weight fractions and diffusion front advances with the elapsed diffusion times at different diffusion temperatures using the Gordon-Taylor equation and core-shell model. We find that the plots of weight fraction of PS vs. elapsed diffusion times at different temperatures can be converted to a master curve by Time-Temperature superposition, and the shift factors obey the Arrhenius equation. Besides, the diffusion front advances of l-PS into g-PPO show an excellent agreement with the t1/2 scaling law at the beginning of the diffusion process, and the diffusion coefficients of different diffusion temperatures also obey the Arrhenius equation. We believe the diffusion mechanism for l-PS/g-PPO should be the Fickean law rather than the Case II, though there are departures of original linearity at longer diffusion times due to the limited liquid supply system. Diffusion of liquid polystyrene into glassy poly(phenylene oxide) characterized by DSC
CYTOKINE GENE VARIATIONS ASSOCIATED WITH TRAIT AND STATE ANXIETY IN ONCOLOGY PATIENTS AND THEIR FAMILY CAREGIVERS

PubMed Central

Miaskowski, Christine; Cataldo, Janine K.; Baggott, Christina R.; West, Claudia; Dunn, Laura B.; Dhruva, Anand; Merriman, John D.; Langford, Dale J.; Kober, Kord M.; Paul, Steven M.; Cooper, Bruce A.; Aouizerat, Bradley E.

2017-01-01

Purpose Anxiety is common among cancer patients and their family caregivers (FCs) and is associated with poorer outcomes. Recently, associations between inflammation and anxiety were identified. However, the relationship between variations in cytokine genes and anxiety warrants investigation. Therefore, phenotypic and genotypic characteristics associated with trait and state anxiety were evaluated in a sample of 167 oncology patients with breast, prostate, lung, or brain cancer and 85 of their FCs. Methods Using multiple regression analyses, the associations between participants’ demographic and clinical characteristics, as well as variations in cytokine genes and trait and state anxiety were evaluated. Results In the bivariate analyses, a number of phenotypic characteristics were associated with both trait and state anxiety (e.g., age, functional status). However, some associations were specific only to trait anxiety (e.g., number of comorbid conditions) or state anxiety (e.g., participation with a FC). Variations in three cytokine genes (i.e., interleukin (IL) 1 beta, IL1 receptor 2 (IL1R2), nuclear factor kappa beta 2 (NFKB2)) were associated with trait anxiety and variations in two genes (i.e., IL1R2, tumor necrosis factor alpha (TNFA)) were associated with state anxiety. Conclusions These findings suggest that both trait and state anxiety need to be assessed in oncology patients and their FCs. Furthermore, variations in cytokine genes may contribute to higher levels of anxiety in oncology patients and their FCs. PMID:25249351
An overview and evaluation of the oncology family caregiver project: improving quality of life and quality of care for oncology family caregivers.

PubMed

Ferrell, Betty; Hanson, Jo; Grant, Marcia

2013-07-01

With changes in health care, oncology family caregivers (FCs) provide the vast majority of patient care. Yet, FCs assume their role with little or no training and with limited resources within the cancer setting to support them. The purpose of this project is to develop and implement a curriculum to improve the quality of life and quality of care for FCs by strengthening cancer care settings in this area. A National Cancer Institute (NCI) R25 grant funded the development of an FC curriculum for professional healthcare providers. The curriculum, based on the City of Hope Quality-of-Life Model, is presented to professionals from cancer centers in national training courses. The project brings together the most current evidence-based knowledge and multiple resources to help improve FC support. Participants develop goals related to implementation and dissemination of the course content and resources in their home institution. Goal evaluation follows at 6, 12, and 18 months. To date, three courses have been presented to 154 teams (322 individuals) representing 39 states. Course evaluations were positive, and participants have initiated institutional FC support goals. Although the goals are diverse, the broad categories include support groups, staff/FC/community education, resource development, assessment tools, and institutional change. There is a critical need to improve support for cancer FCs. This FC training course for professionals is a first step in addressing this need. Copyright © 2012 John Wiley & Sons, Ltd.
A Fluorescence Correlation Spectroscopy Study of the Cryoprotective Mechanism of Glucose on Hemocyanin

NASA Astrophysics Data System (ADS)

Hauger, Eric J.

Cryopreservation is the method of preserving biomaterials by cooling and storing them at very low temperatures. In order to prevent the damaging effects of cooling, cryoprotectants are used to inhibit ice formation. Common cryoprotectants used today include ethylene glycol, propylene glycol, dimethyl sulfoxide, glycerol, and sugars. However, the mechanism responsible for the effectiveness of these cryoprotectants is poorly understood on the molecular level. The water replacement model predicts that water molecules around the surfaces of proteins are replaced with sugar molecules, forming a protective layer against the denaturing ice formation. Under this scheme, one would expect an increase in the hydrodynamic radius with increasing sugar concentration. In order to test this hypothesis, two-photon fluorescence correlation spectroscopy (FCS) was used to measure the hydrodynamic radius of hemocyanin (Hc), an oxygen-carrying protein found in arthropods, in glucose solutions up to 20wt%. FCS found that the hydrodynamic radius was invariant with increasing glucose concentration. Dynamic light scattering (DLS) results verified the hydrodynamic radius of hemocyanin in the absence of glucose. Although this invariant trend seems to indicate that the water replacement hypothesis is invalid the expected glucose layer around the Hc is smaller than the error in the hydrodynamic radius measurements for FCS. The expected change in the hydrodynamic radius with an additional layer of glucose is 1nm, however, the FCS standard error is +/-3.61nm. Therefore, the water replacement model cannot be confirmed nor refuted as a possible explanation for the cryoprotective effects of glucose on Hc.
Changed Hub and Corresponding Functional Connectivity of Subgenual Anterior Cingulate Cortex in Major Depressive Disorder

PubMed Central

Wu, Huawang; Sun, Hui; Xu, Jinping; Wu, Yan; Wang, Chao; Xiao, Jing; She, Shenglin; Huang, Jianwei; Zou, Wenjin; Peng, Hongjun; Lu, Xiaobing; Huang, Guimao; Jiang, Tianzi; Ning, Yuping; Wang, Jiaojian

2016-01-01

Major depressive disorder (MDD) is one of the most prevalent mental disorders. In the brain, the hubs of the brain network play a key role in integrating and transferring information between different functional modules. However, whether the changed pattern in functional network hubs contributes to the onset of MDD remains unclear. Using resting-state functional magnetic resonance imaging (rs-fMRI) and graph theory methods, we investigated whether alterations of hubs can be detected in MDD. First, we constructed the whole-brain voxel-wise functional networks and calculated a functional connectivity strength (FCS) map in each subject in 34 MDD patients and 34 gender-, age- and education level-matched healthy controls (HCs). Next, the two-sample t-test was applied to compare the FCS maps between HC and MDD patients and identified significant decrease of FCS in subgenual anterior cingulate cortex (sgACC) in MDD patients. Subsequent functional connectivity analyses of sgACC showed disruptions in functional connectivity with posterior insula, middle and inferior temporal gyrus, lingual gyrus and cerebellum in MDD patients. Furthermore, the changed FCS of sgACC and functional connections to sgACC were significantly correlated with the Hamilton Depression Rating Scale (HDRS) scores in MDD patients. The results of the present study revealed the abnormal hub of sgACC and its corresponding disrupted frontal-limbic-visual cognitive-cerebellum functional networks in MDD. These findings may provide a new insight for the diagnosis and treatment of MDD. PMID:28018183
The lack of autophagy triggers precocious activation of Notch signaling during Drosophila oogenesis.

PubMed

Barth, Julia M I; Hafen, Ernst; Köhler, Katja

2012-12-05

The proper balance of autophagy, a lysosome-mediated degradation process, is indispensable for oogenesis in Drosophila. We recently demonstrated that egg development depends on autophagy in the somatic follicle cells (FC), but not in the germline cells (GCs). However, the lack of autophagy only affects oogenesis when FCs are autophagy-deficient but GCs are wild type, indicating that a dysfunctional signaling between soma and germline may be responsible for the oogenesis defects. Thus, autophagy could play an essential role in modulating signal transduction pathways during egg development. Here, we provide further evidence for the necessity of autophagy during oogenesis and demonstrate that autophagy is especially required in subsets of FCs. Generation of autophagy-deficient FCs leads to a wide range of phenotypes that are similar to mutants with defects in the classical cell-cell signaling pathways in the ovary. Interestingly, we observe that loss of autophagy leads to a precocious activation of the Notch pathway in the FCs as monitored by the expression of Cut and Hindsight, two downstream effectors of Notch signaling. Our findings point to an unexpected function for autophagy in the modulation of the Notch signaling pathway during Drosophila oogenesis and suggest a function for autophagy in proper receptor activation. Egg development is affected by an imbalance of autophagy between signal sending (germline) and signal receiving cell (FC), thus the lack of autophagy in the germline is likely to decrease the amount of active ligand and accordingly compensates for increased signaling in autophagy-defective follicle cells.
Examining solutions to missing data in longitudinal nursing research.

PubMed

Roberts, Mary B; Sullivan, Mary C; Winchester, Suzy B

2017-04-01

Longitudinal studies are highly valuable in pediatrics because they provide useful data about developmental patterns of child health and behavior over time. When data are missing, the value of the research is impacted. The study's purpose was to (1) introduce a three-step approach to assess and address missing data and (2) illustrate this approach using categorical and continuous-level variables from a longitudinal study of premature infants. A three-step approach with simulations was followed to assess the amount and pattern of missing data and to determine the most appropriate imputation method for the missing data. Patterns of missingness were Missing Completely at Random, Missing at Random, and Not Missing at Random. Missing continuous-level data were imputed using mean replacement, stochastic regression, multiple imputation, and fully conditional specification (FCS). Missing categorical-level data were imputed using last value carried forward, hot-decking, stochastic regression, and FCS. Simulations were used to evaluate these imputation methods under different patterns of missingness at different levels of missing data. The rate of missingness was 16-23% for continuous variables and 1-28% for categorical variables. FCS imputation provided the least difference in mean and standard deviation estimates for continuous measures. FCS imputation was acceptable for categorical measures. Results obtained through simulation reinforced and confirmed these findings. Significant investments are made in the collection of longitudinal data. The prudent handling of missing data can protect these investments and potentially improve the scientific information contained in pediatric longitudinal studies. © 2017 Wiley Periodicals, Inc.
Characterization of protein dynamics in asymmetric cell division by scanning fluorescence correlation spectroscopy.

PubMed

Petrásek, Zdenek; Hoege, Carsten; Mashaghi, Alireza; Ohrt, Thomas; Hyman, Anthony A; Schwille, Petra

2008-12-01

The development and differentiation of complex organisms from the single fertilized egg is regulated by a variety of processes that all rely on the distribution and interaction of proteins. Despite the tight regulation of these processes with respect to temporal and spatial protein localization, exact quantification of the underlying parameters, such as concentrations and distribution coefficients, has so far been problematic. Recent experiments suggest that fluorescence correlation spectroscopy on a single molecule level in living cells has great promise in revealing these parameters with high precision. The optically challenging situation in multicellular systems such as embryos can be ameliorated by two-photon excitation, where scattering background and cumulative photobleaching is limited. A more severe problem is posed by the large range of molecular mobilities observed at the same time, as standard FCS relies strongly on the presence of mobility-induced fluctuations. In this study, we overcame the limitations of standard FCS. We analyzed in vivo polarity protein PAR-2 from eggs of Caenorhabditis elegans by beam-scanning FCS in the cytosol and on the cortex of C. elegans before asymmetric cell division. The surprising result is that the distribution of PAR-2 is largely uncoupled from the movement of cytoskeletal components of the cortex. These results call for a more systematic future investigation of the different cortical elements, and show that the FCS technique can contribute to answering these questions, by providing a complementary approach that can reveal insights not obtainable by other techniques.
Thermal transport at the nanoscale: A Fourier's law vs. phonon Boltzmann equation study

NASA Astrophysics Data System (ADS)

Kaiser, J.; Feng, T.; Maassen, J.; Wang, X.; Ruan, X.; Lundstrom, M.

2017-01-01

Steady-state thermal transport in nanostructures with dimensions comparable to the phonon mean-free-path is examined. Both the case of contacts at different temperatures with no internal heat generation and contacts at the same temperature with internal heat generation are considered. Fourier's law results are compared to finite volume method solutions of the phonon Boltzmann equation in the gray approximation. When the boundary conditions are properly specified, results obtained using Fourier's law without modifying the bulk thermal conductivity are in essentially exact quantitative agreement with the phonon Boltzmann equation in the ballistic and diffusive limits. The errors between these two limits are examined in this paper. For the four cases examined, the error in the apparent thermal conductivity as deduced from a correct application of Fourier's law is less than 6%. We also find that the Fourier's law results presented here are nearly identical to those obtained from a widely used ballistic-diffusive approach but analytically much simpler. Although limited to steady-state conditions with spatial variations in one dimension and to a gray model of phonon transport, the results show that Fourier's law can be used for linear transport from the diffusive to the ballistic limit. The results also contribute to an understanding of how heat transport at the nanoscale can be understood in terms of the conceptual framework that has been established for electron transport at the nanoscale.
Universal scaling laws of diffusion in two-dimensional granular liquids.

PubMed

Wang, Chen-Hung; Yu, Szu-Hsuan; Chen, Peilong

2015-06-01

We find, in a two-dimensional air table granular system, that the reduced diffusion constant D* and excess entropy S(2) follow two distinct scaling laws: D*∼e(S(2)*) for dense liquids and D∼e(3S(2)*) for dilute ones. The scaling for dense liquids is very similar to that for three-dimensional liquids proposed previously [M. Dzugutov, Nature (London) 381, 137 (1996); A. Samanta et al., Phys. Rev. Lett. 92, 145901 (2004)]. In the dilute regime, a power law [Y. Rosenfeld, J. Phys.: Condens. Matter 11, 5415 (1999)] also fits our data reasonably well. In our system, particles experience low air drag dissipation and interact with each others through embedded magnets. These near-conservative many-body interactions are responsible for the measured Gaussian velocity distribution functions and the scaling laws. The dominance of cage relaxations in dense liquids leads to the different scaling laws for dense and dilute regimes.
The γ-ray emission produced by protons that escape from supernova remnant G349.7+0.2

NASA Astrophysics Data System (ADS)

Zhang, Xiao; Li, Hui; Chen, Yang

2016-10-01

G349.7+0.2 is an interacting supernova remnant (SNR) expanding in a dense medium. Recently, a very strong γ-ray source coincident with this SNR has been revealed by Fermi-LAT and H.E.S.S. observations which shows a broken power-law-like spectrum. An escaping-diffusion model, including the power-law and δ-function injection, is applied to this source which can naturally explain the spectral feature in both the GeV and TeV regime. We use the Markov Chain Monte Carlo method to constrain the model parameters and find that the correction factor of slow diffusion around this SNR, χ ˜ 0.01 for power-law injection and χ ˜ 0.1 for δ-function injection, can fit the data best with reasonable molecular cloud mass. This slow diffusion is also consistent with previous results from both phenomenological models and theoretical predication.
NUMERICAL ANALYSES FOR TREATING DIFFUSION IN SINGLE-, TWO-, AND THREE-PHASE BINARY ALLOY SYSTEMS

NASA Technical Reports Server (NTRS)

Tenney, D. R.

1994-01-01

This package consists of a series of three computer programs for treating one-dimensional transient diffusion problems in single and multiple phase binary alloy systems. An accurate understanding of the diffusion process is important in the development and production of binary alloys. Previous solutions of the diffusion equations were highly restricted in their scope and application. The finite-difference solutions developed for this package are applicable for planar, cylindrical, and spherical geometries with any diffusion-zone size and any continuous variation of the diffusion coefficient with concentration. Special techniques were included to account for differences in modal volumes, initiation and growth of an intermediate phase, disappearance of a phase, and the presence of an initial composition profile in the specimen. In each analysis, an effort was made to achieve good accuracy while minimizing computation time. The solutions to the diffusion equations for single-, two-, and threephase binary alloy systems are numerically calculated by the three programs NAD1, NAD2, and NAD3. NAD1 treats the diffusion between pure metals which belong to a single-phase system. Diffusion in this system is described by a one-dimensional Fick's second law and will result in a continuous composition variation. For computational purposes, Fick's second law is expressed as an explicit second-order finite difference equation. Finite difference calculations are made by choosing the grid spacing small enough to give convergent solutions of acceptable accuracy. NAD2 treats diffusion between pure metals which form a two-phase system. Diffusion in the twophase system is described by two partial differential equations (a Fick's second law for each phase) and an interface-flux-balance equation which describes the location of the interface. Actual interface motion is obtained by a mass conservation procedure. To account for changes in the thicknesses of the two phases as diffusion progresses, a variable grid technique developed by Murray and Landis is employed. These equations are expressed in finite difference form and solved numerically. Program NAD3 treats diffusion between pure metals which form a two-phase system with an intermediate third phase. Diffusion in the three-phase system is described by three partial differential expressions of Fick's second law and two interface-flux-balance equations. As with the two-phase case, a variable grid finite difference is used to numerically solve the diffusion equations. Computation time is minimized without sacrificing solution accuracy by treating the three-phase problem as a two-phase problem when the thickness of the intermediate phase is less than a preset value. Comparisons between these programs and other solutions have shown excellent agreement. The programs are written in FORTRAN IV for batch execution on the CDC 6600 with a central memory requirement of approximately 51K (octal) 60 bit words.
Entry flight control system downmoding evaluation

NASA Technical Reports Server (NTRS)

Barnes, H. A.

1978-01-01

A method to desensitize the entry flight control system to structural vibration feedback which might induce an oscillatory instability is described. Trends in vehicle response and handling characteristics as a function of gain combinations in the FCS forward and rate feedback loops were described as observed in a man-in-the-loop simulation. Among the flight conditions considered are the effects of downmoding with APU failures, off-nominal trajectory conditions, sensed angle of attack errors, the impact on RCS fuel consumption, performance in the presence of aero variations, recovery from large FCS upsets, and default gains.
CO2 diffusion in champagne wines: a molecular dynamics study.

PubMed

Perret, Alexandre; Bonhommeau, David A; Liger-Belair, Gérard; Cours, Thibaud; Alijah, Alexander

2014-02-20

Although diffusion is considered as the main physical process responsible for the nucleation and growth of carbon dioxide bubbles in sparkling beverages, the role of each type of molecule in the diffusion process remains unclear. In the present study, we have used the TIP5P and SPC/E water models to perform force field molecular dynamics simulations of CO2 molecules in water and in a water/ethanol mixture respecting Champagne wine proportions. CO2 diffusion coefficients were computed by applying the generalized Fick's law for the determination of multicomponent diffusion coefficients, a law that simplifies to the standard Fick's law in the case of champagnes. The CO2 diffusion coefficients obtained in pure water and water/ethanol mixtures composed of TIP5P water molecules were always found to exceed the coefficients obtained in mixtures composed of SPC/E water molecules, a trend that was attributed to a larger propensity of SPC/E water molecules to form hydrogen bonds. Despite the fact that the SPC/E model is more accurate than the TIP5P model to compute water self-diffusion and CO2 diffusion in pure water, the diffusion coefficients of CO2 molecules in the water/ethanol mixture are in much better agreement with the experimental values of 1.4 - 1.5 × 10(-9) m(2)/s obtained for Champagne wines when the TIP5P model is employed. This difference was deemed to rely on the larger propensity of SPC/E water molecules to maintain the hydrogen-bonded network between water molecules and form new hydrogen bonds with ethanol, although statistical issues cannot be completely excluded. The remarkable agreement between the theoretical CO2 diffusion coefficients obtained within the TIP5P water/ethanol mixture and the experimental data specific to Champagne wines makes us infer that the diffusion coefficient in these emblematic hydroalcoholic sparkling beverages is expected to remain roughly constant whathever their proportions in sugars, glycerol, or peptides.
Diffusion of residual monomer in polymer resins.

PubMed Central

Piver, W T

1976-01-01

A simplified mathematical model which made use of Fick's laws of diffusion written in spherical coordinates was developed to describe the rate of diffusion of residual monomers from polymer resins. The properties of the monomer-polymer system which influenced the amount of monomer remaining in the polymer as a function of time were the diffusivity and solubility of the monomer in the polymer, and the particle size of the polymer resin. This model was used to analyze literature data on the diffusion of residual vinyl chloride monomer in polyvinyl chloride resins made by the suspension process. It was concluded that particle size of the resin was a significant parameter which should be taken advantage of in process equipment designed to remove residual monomer from PVC resins. The diffusivity of the monomer in the polymer was a function of the solubility of the monomer in the polymer. Monomer solubility can be determined from Henry's law. It was suggested that this model could be adapted to describe diffusion of monomers from any monomer-polymer system, and would be a useful approach to modeling the transport of nonreactive chemical additives from plastics. PMID:1026410
Electrohydrodynamic properties of succinoglycan as probed by fluorescence correlation spectroscopy, potentiometric titration and capillary electrophoresis.

PubMed

Duval, Jérôme F L; Slaveykova, Vera I; Hosse, Monika; Buffle, Jacques; Wilkinson, Kevin J

2006-10-01

The electrostatic, hydrodynamic and conformational properties of aqueous solutions of succinoglycan have been analyzed by fluorescence correlation spectroscopy (FCS), proton titration, and capillary electrophoresis (CE) over a large range of pH values and electrolyte (NaCl) concentrations. Using the theoretical formalism developed previously for the electrokinetic properties of soft, permeable particles, a quantitative analysis for the electro-hydrodynamics of succinoglycan is performed by taking into account, in a self-consistent manner, the measured values of the diffusion coefficients, electric charge densities, and electrophoretic mobilities. For that purpose, two limiting conformations for the polysaccharide in solution are tested, i.e. succinoglycan behaves as (i) a spherical, random coil polymer or (ii) a rodlike particle with charged lateral chains. The results show that satisfactory modeling of the titration data for ionic strengths larger than 50 mM can be accomplished using both geometries over the entire range of pH values. Electrophoretic mobilities measured for sufficiently large pH values (pH > 5-6) are in line with predictions based on either model. The best manner to discriminate between these two conceptual models is briefly discussed. For low pH values (pH < 5), both models indicate aggregation, resulting in an increase of the hydrodynamic permeability and a decrease of the diffusion coefficient.
Scaling laws of passive-scalar diffusion in the interstellar medium

NASA Astrophysics Data System (ADS)

Colbrook, Matthew J.; Ma, Xiangcheng; Hopkins, Philip F.; Squire, Jonathan

2017-05-01

Passive-scalar mixing (metals, molecules, etc.) in the turbulent interstellar medium (ISM) is critical for abundance patterns of stars and clusters, galaxy and star formation, and cooling from the circumgalactic medium. However, the fundamental scaling laws remain poorly understood in the highly supersonic, magnetized, shearing regime relevant for the ISM. We therefore study the full scaling laws governing passive-scalar transport in idealized simulations of supersonic turbulence. Using simple phenomenological arguments for the variation of diffusivity with scale based on Richardson diffusion, we propose a simple fractional diffusion equation to describe the turbulent advection of an initial passive scalar distribution. These predictions agree well with the measurements from simulations, and vary with turbulent Mach number in the expected manner, remaining valid even in the presence of a large-scale shear flow (e.g. rotation in a galactic disc). The evolution of the scalar distribution is not the same as obtained using simple, constant 'effective diffusivity' as in Smagorinsky models, because the scale dependence of turbulent transport means an initially Gaussian distribution quickly develops highly non-Gaussian tails. We also emphasize that these are mean scalings that apply only to ensemble behaviours (assuming many different, random scalar injection sites): individual Lagrangian 'patches' remain coherent (poorly mixed) and simply advect for a large number of turbulent flow-crossing times.

Master equation for She-Leveque scaling and its classification in terms of other Markov models of developed turbulence

NASA Astrophysics Data System (ADS)

Nickelsen, Daniel

2017-07-01

The statistics of velocity increments in homogeneous and isotropic turbulence exhibit universal features in the limit of infinite Reynolds numbers. After Kolmogorov’s scaling law from 1941, many turbulence models aim for capturing these universal features, some are known to have an equivalent formulation in terms of Markov processes. We derive the Markov process equivalent to the particularly successful scaling law postulated by She and Leveque. The Markov process is a jump process for velocity increments u(r) in scale r in which the jumps occur randomly but with deterministic width in u. From its master equation we establish a prescription to simulate the She-Leveque process and compare it with Kolmogorov scaling. To put the She-Leveque process into the context of other established turbulence models on the Markov level, we derive a diffusion process for u(r) using two properties of the Navier-Stokes equation. This diffusion process already includes Kolmogorov scaling, extended self-similarity and a class of random cascade models. The fluctuation theorem of this Markov process implies a ‘second law’ that puts a loose bound on the multipliers of the random cascade models. This bound explicitly allows for instances of inverse cascades, which are necessary to satisfy the fluctuation theorem. By adding a jump process to the diffusion process, we go beyond Kolmogorov scaling and formulate the most general scaling law for the class of Markov processes having both diffusion and jump parts. This Markov scaling law includes She-Leveque scaling and a scaling law derived by Yakhot.
Can the caged bird sing? Reflections on the application of qualitative research methods to case study design in homeopathic medicine

PubMed Central

Thompson, Trevor DB

2004-01-01

Background Two main pathways exist for the development of knowledge in clinical homeopathy. These comprise clinical trials conducted primarily by university-based researchers and cases reports and homeopathic "provings" compiled by engaged homeopathic practitioners. In this paper the relative merits of these methods are examined and a middle way proposed. This consists of the "Formal Case Study" (FCS) in which qualitative methods are used to increase the rigour and sophistication with which homeopathic cases are studied. Before going into design issues this paper places the FCS in an historical and academic context and describes the relative merits of the method. Discussion Like any research, the FCS should have a clear focus. This focus can be both "internal", grounded in the discourse of homeopathy and also encompass issues of wider appeal. A selection of possible "internal" and "external" research questions is introduced. Data generation should be from multiple sources to ensure adequate triangulation. This could include the recording and transcription of actual consultations. Analysis is built around existing theory, involves cross-case comparison and the search for deviant cases. The trustworthiness of conclusions is ensured by the application of concepts from qualitative research including triangulation, groundedness, respondent validation and reflexivity. Though homeopathic case studies have been reported in mainstream literature, none has used formal qualitative methods – though some such studies are in progress. Summary This paper introduces the reader to a new strategy for homeopathic research. This strategy, termed the "formal case study", allows for a naturalistic enquiry into the players, processes and outcomes of homeopathic practice. Using ideas from qualitative research, it allows a rigorous approach to types of research question that cannot typically be addressed through clinical trials and numeric outcome studies. The FCS provides an opportunity for the practitioner-researcher to contribute to the evidence-base in homeopathy in a systematic fashion. The FCS can also be used to inform the design of clinical trials through holistic study of the "active ingredients" of the therapeutic process and its clinical outcomes. PMID:15018637
Evaluation of two-fold fully conditional specification multiple imputation for longitudinal electronic health record data

PubMed Central

Welch, Catherine A; Petersen, Irene; Bartlett, Jonathan W; White, Ian R; Marston, Louise; Morris, Richard W; Nazareth, Irwin; Walters, Kate; Carpenter, James

2014-01-01

Most implementations of multiple imputation (MI) of missing data are designed for simple rectangular data structures ignoring temporal ordering of data. Therefore, when applying MI to longitudinal data with intermittent patterns of missing data, some alternative strategies must be considered. One approach is to divide data into time blocks and implement MI independently at each block. An alternative approach is to include all time blocks in the same MI model. With increasing numbers of time blocks, this approach is likely to break down because of co-linearity and over-fitting. The new two-fold fully conditional specification (FCS) MI algorithm addresses these issues, by only conditioning on measurements, which are local in time. We describe and report the results of a novel simulation study to critically evaluate the two-fold FCS algorithm and its suitability for imputation of longitudinal electronic health records. After generating a full data set, approximately 70% of selected continuous and categorical variables were made missing completely at random in each of ten time blocks. Subsequently, we applied a simple time-to-event model. We compared efficiency of estimated coefficients from a complete records analysis, MI of data in the baseline time block and the two-fold FCS algorithm. The results show that the two-fold FCS algorithm maximises the use of data available, with the gain relative to baseline MI depending on the strength of correlations within and between variables. Using this approach also increases plausibility of the missing at random assumption by using repeated measures over time of variables whose baseline values may be missing. PMID:24782349
Increased acid ceramidase expression depends on upregulation of androgen-dependent deubiquitinases, USP2, in a human prostate cancer cell line, LNCaP.

PubMed

Mizutani, Naoki; Inoue, Minami; Omori, Yukari; Ito, Hiromi; Tamiya-Koizumi, Keiko; Takagi, Akira; Kojima, Tetsuhito; Nakamura, Mitsuhiro; Iwaki, Soichiro; Nakatochi, Masahiro; Suzuki, Motoshi; Nozawa, Yoshinori; Murate, Takashi

2015-10-01

Acid ceramidase (ACDase) metabolizes ceramide to sphingosine, leading to sphingosine 1-phosphate production. Reportedly, ACDase has been upregulated in prostate cancer. However, its regulatory mechanism remains unclear. LNCaP (androgen-sensitive prostate cancer cell line) but not PC3 and DU-145, (androgen-unresponsive cell lines) exhibited the highest ACDase protein. Among three cell lines, ASAH1 mRNA level was not correlated with ACDase protein expression, and the 5'-promoter activity did not show androgen dependency, suggesting the post-transcriptional regulation of ACDase in LNCaP cells. Based on these results, LNCaP was analysed further. Casodex, androgen receptor antagonist, and charcoal-stripped FCS (CS-FCS) decreased ACDase protein and activity, whereas dihydrotestosterone in CS-FCS culture increased ACDase protein and enzyme activity. MG132, a proteasome inhibitor, prevented the decrease of ACDase protein when cultured in CS-FCS, suggesting the involvement of ubiquitin/proteasome system. Reportedly, USP2, a deubiquitinase, plays an important role in LNCaP cells. USP2 siRNA decreased ACDase protein, whereas USP2 overexpression increased ACDase protein of LNCaP cells. However, SKP2, an ubiquitin E3 ligase known to be active in prostate cancer, did not affect androgen-dependent ACDase expression in LNCaP cells. Thus, ACDase regulation by androgen in androgen-sensitive LNCaP cells is mainly due to its prolonged protein half-life by androgen-stimulated USP2 expression. © The Authors 2015. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.
Bone Tissue Engineering Under Xenogeneic-Free Conditions in a Large Animal Model as a Basis for Early Clinical Applicability.

PubMed

Weigand, Annika; Beier, Justus P; Schmid, Rafael; Knorr, Tobias; Kilian, David; Götzl, Rebekka; Gerber, Thomas; Horch, Raymund E; Boos, Anja M

2017-03-01

For decades, researchers have been developing a range of promising strategies in bone tissue engineering with the aim of producing a significant clinical benefit over existing therapies. However, a major problem concerns the traditional use of xenogeneic substances for the expansion of cells, which complicates direct clinical transfer. The study's aim was to establish a totally autologous sheep model as a basis for further preclinical studies and future clinical application. Ovine mesenchymal stromal cells (MSC) were cultivated in different concentrations (0%, 2%, 5%, 10%, and 25%) of either autologous serum (AS) or fetal calf serum (FCS). With an increase of serum concentration, enhanced metabolic activity and proliferation could be observed. There were minor differences between MSC cultivated in AS or FCS, comparing gene and protein expression of osteogenic and stem cell markers, morphology, and osteogenic differentiation. MSC implanted subcutaneously in the sheep model, together with a nanostructured bone substitute, either in stable block or moldable putty form, induced similar vascularization and remodeling of the bone substitute irrespective of cultivation of MSC in AS or FCS and osteogenic differentiation. The bone substitute in block form together with MSC proved particularly advantageous in the induction of ectopic bone formation compared to the cell-free control and putty form. It could be demonstrated that AS is suitable for replacement of FCS for cultivation of ovine MSC for bone tissue engineering purposes. Substantial progress has been made in the development of a strictly xenogeneic-free preclinical animal model to bring future clinical application of bone tissue engineering strategies within reach.
Validity of food consumption indicators in the Lao context: moving toward cross-cultural standardization.

PubMed

Baumann, Soo Mee; Webb, Patrick; Zeller, Manfred

2013-03-01

Cross-cultural validity of food security indicators is commonly presumed without questioning the suitability of generic indicators in different geographic settings. However, ethnic differences in the perception of and reporting on, food insecurity, as well as variations in consumption patterns, may limit the comparability of results. Although research on correction factors for standardization of food security indicators is in process, so far no universal indicator has been identified. The current paper considers the ability of the Food Consumption Score (FCS) developed by the World Food Programme in southern Africa in 1996 to meet the requirement of local cultural validity in a Laotian context. The analysis is based on research that seeks to identify options for correcting possible biases linked to cultural disparities. Based on the results of a household survey conducted in different agroecological zones of Laos in 2009, the FCS was validated against a benchmark of calorie consumption. Changing the thresholds and excluding small amounts of food items consumed were tested as options to correct for biases caused by cultural disparities. The FCS in its original form underestimates the food insecurity level in the surveyed villages. However, the closeness of fit of the FCS to the benchmark classification improves when small amounts of food items are excluded from the assessment. Further research in different cultural settings is required to generate more insight into the extent to which universal thresholds can be applied to dietary diversity indicators with or without locally determined correction factors such as the exclusion of small amounts of food items.
Chondrocyte-based intraoperative processing strategies for the biological augmentation of a polyurethane meniscus replacement.

PubMed

Vedicherla, Srujana; Romanazzo, Sara; Kelly, Daniel J; Buckley, Conor T; Moran, Cathal J

2017-11-28

Purpose/aim of study: Menisectomies account for over 1.5 million surgical interventions in Europe annually, and there is a growing interest in regenerative strategies to improve outcomes in meniscal replacement. The overall objective of this study was to evaluate the role of intraoperatively applied fresh chondrocyte (FC) isolates compared to minced cartilage (MC) fragments, used without cell isolation, to improve bioactivity and tissue integration when combined with a polyurethane replacement. First, to optimize the intraoperative cell isolation protocol, caprine articular cartilage biopsies were digested with 750 U/ml or 3000 U/ml collagenase type II (ratio of 10 ml per g of tissue) for 30 min, 1 h or 12 h with constant agitation and compared to culture-expanded chondrocytes in terms of matrix deposition when cultured on polyurethane scaffolds. Finally, FCs and MC-augmented polyurethane scaffolds were evaluated in a caprine meniscal explant model to assess the potential enhancements on tissue integration strength. Adequate numbers of FCs were harvested using a 30 min chondrocyte isolation protocol and were found to demonstrate improved matrix deposition compared to standard culture-expanded cells in vitro. Upon evaluation in a meniscus explant defect model, both FCs and MC showed improved matrix deposition at the tissue-scaffold interface and enhanced push-out strength, fourfold and 2.5-fold, respectively, compared with the acellular implant. Herein, we have demonstrated a novel approach that could be applied intraoperatively, using FCs or MC for improved tissue integration with a polyurethane meniscal replacement.
Hydrodynamic size-dependent cellular uptake of aqueous QDs probed by fluorescence correlation spectroscopy.

PubMed

Dong, Chaoqing; Irudayaraj, Joseph

2012-10-11

Aqueous quantum dots (QDs) directly synthesized with various thiol ligands have been investigated as imaging probes in living cells. However, the effect of the surface chemistry of these ligands on QDs' cellular uptakes and their intracellular fate remains poorly understood. In this work, four CdTe QDs were directly synthesized under aqueous conditions using four different thiols as stabilizers and their interactions with cells were investigated. Fluorescence correlation spectroscopy (FCS), X-ray photoelectron spectroscopy (XPS), and zeta potential measurements on QDs primarily show that the surface structure of these QDs is highly dependent on the thiol ligands used in the preparation of QDs' precursors, including its layer thicknesses, densities, and surface charges. Subsequently, FCS integrated with the maximum-entropy-method-based FCS (MEMFCS) was used to investigate the concentration distribution and dynamics of these QDs in living A-427 cells. Our findings indicate that QDs' surface characteristics affect cell membrane adsorption and subsequent internalization. More critically, we show that the cellular uptake of aqueous QDs is dependent on their hydrodynamic diameter and might have the potential to escape trapped environments to accumulate in the cytoplasm.
Infectivity of Theileria parva sporozoites following cryopreservation in four suspension media and multiple refreezing: evaluation by in vitro titration.

PubMed

Mbao, V; Berkvens, D; Dolan, T; Speybroeck, N; Brandt, J; Dorny, P; Van den Bossche, P; Marcotty, T

2006-09-01

Theileria parva sporozoite stabilates are used for immunizing cattle against East Coast fever and in in vitro sporozoite neutralization assays. In this study, we attempted to identify a cheaper freezing medium and quantified the infectivity loss of sporozoites due to refreezing of stabilates, using an in vitro technique. Pools of stabilates prepared using Minimum Essential Medium (MEM), Roswell Park Memorial Institute (RPMI 1640), foetal calf serum (FCS) and phosphate-buffered saline (PBS) were compared. All were supplemented with bovine serum albumin except the FCS. RPMI 1640 was as effective as MEM in maintaining sporozoite infectivity while the infectivity in PBS and FCS reached only 59% and 67%, respectively. In a second experiment, a stabiiate based on MEM was subjected to several freeze-thaw cycles including various holding times on ice between thawing and refreezing. Refrozen stabilate gave an average sporozoite infectivity loss of 35% per cycle. The results indicate that RPMI can be used as a cheaper freezing medium for T. parva stabilates and that refrozen stabilate doses need to be adjusted for the 35% loss of infectivity.
Protein-enhanced soups: a consumer-accepted food for increasing dietary protein provision among older adults.

PubMed

Donahue, Elizabeth; Crowe, Kristi Michele; Lawrence, Jeannine

2015-02-01

Protein-enhanced soups (PES) may improve protein intake among older adults. This study examined sensory attributes (aroma, texture, taste, and overall acceptability) and preferences of PES (chicken noodle and cheddar broccoli) compared with flavor-matched control soups (FCS) among older adults (≥65 years) and evaluated dietary profile changes of a standard menu based on the substitution of one PES serving/d for a standard soup. Modified paired preference tests and 5-point facial hedonic scales were administered to participants (n = 44). No significant differences in sensory attributes between either PES compared with FCS were identified, but significant gender- and age-related differences (p < 0.05) were observed. About Sixty-one percent of participants preferred protein-enhanced chicken noodle soup while only 38% preferred protein-enhanced cheddar broccoli soup to their respective FCS. Substituting one PES serving for one non-fortified soup serving per day resulted in significantly higher (p < 0.001) protein profile. Results suggest that all attributes of PES were consistent with sensory expectations and PES substitution could improve protein provision.
"Sizing" the oligomers of Azami Green fluorescent protein with FCS and antibunching

NASA Astrophysics Data System (ADS)

Temirov, Jamshid; Werner, James H.; Goodwin, Peter M.; Bradbury, Andrew R. M.

2012-02-01

Fluorescent proteins are invaluable molecules in fluorescence microscopy and spectroscopy. The size and brightness of fluorescent proteins often dictates the application they may be used for. While a monomeric protein may be the least perturbative structure for labeling a protein in a cell, often oligomers (dimers and tetramers) of fluorescent proteins can be more stable. However, from a quantitative microscopy standpoint, it is important to realize the photophysical properties of monomers do not necessarily multiply by their number when they form oligomers. In this work we studied oligomerization states of the Azami Green (AG) protein with fluorescence correlation spectroscopy (FCS) and photon antibunching or photon pair correlation spectroscopy (PPCS). FCS was used to measure the hydrodynamic size of the oligomers, whereas antibunching was used to count the number of fluorescent emitters in the oligomers. The results exhibited that the dimers of AG were single emitters and the tetramers were dual-emitters, indicative of dipole-dipole interactions and energy transfer between the monomeric units. We also used these methods to estimate the number of fluorescent proteins displayed on T7 phage molecules.
A new model predictive control algorithm by reducing the computing time of cost function minimization for NPC inverter in three-phase power grids.

PubMed

Taheri, Asghar; Zhalebaghi, Mohammad Hadi

2017-11-01

This paper presents a new control strategy based on finite-control-set model-predictive control (FCS-MPC) for Neutral-point-clamped (NPC) three-level converters. Containing some advantages like fast dynamic response, easy inclusion of constraints and simple control loop, makes the FCS-MPC method attractive to use as a switching strategy for converters. However, the large amount of required calculations is a problem in the widespread of this method. In this way, to resolve this problem this paper presents a modified method that effectively reduces the computation load compare with conventional FCS-MPC method and at the same time does not affect on control performance. The proposed method can be used for exchanging power between electrical grid and DC resources by providing active and reactive power compensations. Experiments on three-level converter for three Power Factor Correction (PFC), inductive and capacitive compensation modes verify the good and comparable performance. The results have been simulated using MATLAB/SIMULINK software. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.
Size quantization in high-temperature superconducting cuprates and a link to Einstein's diffusion law

NASA Astrophysics Data System (ADS)

Roeser, H. P.; Bohr, A.; Haslam, D. T.; López, J. S.; Stepper, M.; Nikoghosyan, A. S.

2012-07-01

Optimum doping of high-temperature superconductors (HTSC) defines a superconducting unit volume for each HTSC. For a single-mode HTSC, e.g., a cuprate with one CuO2 plane, the volume is given by Vsc=cx2, where c is the unit cell height and x the doping distance. The experimental resistivity at Tc is connected to the structure by ρ(exp)≈c×h/(2e2). Combining this result with the classical definition of resistivity leads to an equation similar to Einstein's diffusion law x2/(2τ)=h/(2Meff)=D, where τ is the relaxation time, Meff=2me and D the diffusion constant. It has also been shown that the mean free path d=x. The Einstein-Smoluchowski diffusion relation D=μkBTc provides a connection to Tc.
Dynamics of the diffusive DM-DE interaction – Dynamical system approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haba, Zbigniew; Stachowski, Aleksander; Szydłowski, Marek, E-mail: zhab@ift.uni.wroc.pl, E-mail: aleksander.stachowski@uj.edu.pl, E-mail: marek.szydlowski@uj.edu.pl

We discuss dynamics of a model of an energy transfer between dark energy (DE) and dark matter (DM) . The energy transfer is determined by a non-conservation law resulting from a diffusion of dark matter in an environment of dark energy. The relativistic invariance defines the diffusion in a unique way. The system can contain baryonic matter and radiation which do not interact with the dark sector. We treat the Friedman equation and the conservation laws as a closed dynamical system. The dynamics of the model is examined using the dynamical systems methods for demonstration how solutions depend on initialmore » conditions. We also fit the model parameters using astronomical observation: SNIa, H ( z ), BAO and Alcock-Paczynski test. We show that the model with diffuse DM-DE is consistent with the data.« less
General solution for diffusion-controlled dissolution of spherical particles. 1. Theory.

PubMed

Wang, J; Flanagan, D R

1999-07-01

Three classical particle dissolution rate expressions are commonly used to interpret particle dissolution rate phenomena. Our analysis shows that an assumption used in the derivation of the traditional cube-root law may not be accurate under all conditions for diffusion-controlled particle dissolution. Mathematical analysis shows that the three classical particle dissolution rate expressions are approximate solutions to a general diffusion layer model. The cube-root law is most appropriate when particle size is much larger than the diffusion layer thickness, the two-thirds-root expression applies when the particle size is much smaller than the diffusion layer thickness. The square-root expression is intermediate between these two models. A general solution to the diffusion layer model for monodispersed spherical particles dissolution was derived for sink and nonsink conditions. Constant diffusion layer thickness was assumed in the derivation. Simulated dissolution data showed that the ratio between particle size and diffusion layer thickness (a0/h) is an important factor in controlling the shape of particle dissolution profiles. A new semiempirical general particle dissolution equation is also discussed which encompasses the three classical particle dissolution expressions. The success of the general equation in explaining limitations of traditional particle dissolution expressions demonstrates the usefulness of the general diffusion layer model.
Spacecraft Observations of Oblique Electron Beams Breaking the Frozen-In Law During Asymmetric Reconnection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Egedal, J.; Le, Ari; Daughton, William

Fully kinetic simulations of asymmetric magnetic reconnection reveal the presence of magnetic-field-aligned beams of electrons flowing toward the topological magnetic x line. Within the ~ 6d e electron-diffusion region, the beams become oblique to the local magnetic field, providing a unique signature of the electron-diffusion region where the electron frozen-in law is broken. These numerical predictions are confirmed by in situ Magnetospheric Multiscale spacecraft observations during asymmetric reconnection at Earth’s dayside magnetopause.
Spacecraft Observations of Oblique Electron Beams Breaking the Frozen-In Law During Asymmetric Reconnection

DOE PAGES

Egedal, J.; Le, Ari; Daughton, William; ...

2018-01-29

Fully kinetic simulations of asymmetric magnetic reconnection reveal the presence of magnetic-field-aligned beams of electrons flowing toward the topological magnetic x line. Within the ~ 6d e electron-diffusion region, the beams become oblique to the local magnetic field, providing a unique signature of the electron-diffusion region where the electron frozen-in law is broken. These numerical predictions are confirmed by in situ Magnetospheric Multiscale spacecraft observations during asymmetric reconnection at Earth’s dayside magnetopause.
The Israeli Patient's Rights Law: evidence for deprofessionalization?

PubMed

Anson, O

1999-01-01

In this paper, the Israeli Patient's Rights Law of 1996 is discussed within the framework of Haug's predicted process of deprofessionalization. It is argued that the law reflects global processes such as the diffusion of knowledge, consumerism, and values that emphasize human rights and democracy. By guaranteeing patients' access to medical information, by submitting medical decisions to extra-professional regulation, the law erodes professional power.
Numerical simulation of conservation laws

NASA Technical Reports Server (NTRS)

Chang, Sin-Chung; To, Wai-Ming

1992-01-01

A new numerical framework for solving conservation laws is being developed. This new approach differs substantially from the well established methods, i.e., finite difference, finite volume, finite element and spectral methods, in both concept and methodology. The key features of the current scheme include: (1) direct discretization of the integral forms of conservation laws, (2) treating space and time on the same footing, (3) flux conservation in space and time, and (4) unified treatment of the convection and diffusion fluxes. The model equation considered in the initial study is the standard one dimensional unsteady constant-coefficient convection-diffusion equation. In a stability study, it is shown that the principal and spurious amplification factors of the current scheme, respectively, are structurally similar to those of the leapfrog/DuFort-Frankel scheme. As a result, the current scheme has no numerical diffusion in the special case of pure convection and is unconditionally stable in the special case of pure diffusion. Assuming smooth initial data, it will be shown theoretically and numerically that, by using an easily determined optimal time step, the accuracy of the current scheme may reach a level which is several orders of magnitude higher than that of the MacCormack scheme, with virtually identical operation count.
Fokker-Planck diffusive law: its interpretation in the context of plasma transport modeling

NASA Astrophysics Data System (ADS)

Sanchez, Raul; Carreras, Ben A.; van Milligen, Boudewijn Ph.

2006-10-01

It was recently proposed that, when building phenomenological transport models for particle transport in tokamaks, use of the Fokker-Planck diffusive law might be preferable to Fick's law to express particle fluxes [1]. In particular, it might offer a possible explanation for the excessive pinch velocites observed in some experimental situations with respect to the values expected from the forces and asymmetries existent in the system. In spite of the fact that Fokker-Planck's law was first proposed many years ago, it produces a series of counterintuitive results that at first sight seem in contradiction with the second law of thermodynamics. In this contribution we will review the basic concepts behind its formulation and show that, through the use of simple examples relevant to plasma physics, the second law of thermodynamics is not violated in any manner if properly used. The benefits of its use within the modelling of transport in tokamaks will also be clarified.REFERENCES: [1] R. Sanchez et al, Phys. Plasmas 12, 056105 (2005); B.Ph. van Milligen et al, Plasma Phys.Contr.Fusion 47, B743 (2005)

Understanding Diffusion Theory and Fick's Law through Food and Cooking

ERIC Educational Resources Information Center

Zhou, Larissa; Nyberg, Kendra; Rowat, Amy C.

2015-01-01

Diffusion is critical to physiological processes ranging from gas exchange across alveoli to transport within individual cells. In the classroom, however, it can be challenging to convey the concept of diffusion on the microscopic scale. In this article, we present a series of three exercises that use food and cooking to illustrate diffusion…
Analysis of mass incident diffusion in Weibo based on self-organization theory

NASA Astrophysics Data System (ADS)

Pan, Jun; Shen, Huizhang

2018-02-01

This study introduces some theories and methods of self-organization system to the research of the diffusion mechanism of mass incidents in Weibo (Chinese Twitter). Based on the analysis on massive Weibo data from Songjiang battery factory incident happened in 2013 and Jiiangsu Qidong OJI PAPER incident happened in 2012, we find out that diffusion system of mass incident in Weibo satisfies Power Law, Zipf's Law, 1/f noise and Self-similarity. It means this system is the self-organization criticality system and dissemination bursts can be understood as one kind of Self-organization behavior. As the consequence, self-organized criticality (SOC) theory can be used to explain the evolution of mass incident diffusion and people may come up with the right strategy to control such kind of diffusion if they can handle the key ingredients of Self-organization well. Such a study is of practical importance which can offer opportunities for policy makers to have good management on these events.
The precise time-dependent solution of the Fokker–Planck equation with anomalous diffusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Ran; Du, Jiulin, E-mail: jiulindu@aliyun.com

2015-08-15

We study the time behavior of the Fokker–Planck equation in Zwanzig’s rule (the backward-Ito’s rule) based on the Langevin equation of Brownian motion with an anomalous diffusion in a complex medium. The diffusion coefficient is a function in momentum space and follows a generalized fluctuation–dissipation relation. We obtain the precise time-dependent analytical solution of the Fokker–Planck equation and at long time the solution approaches to a stationary power-law distribution in nonextensive statistics. As a test, numerically we have demonstrated the accuracy and validity of the time-dependent solution. - Highlights: • The precise time-dependent solution of the Fokker–Planck equation with anomalousmore » diffusion is found. • The anomalous diffusion satisfies a generalized fluctuation–dissipation relation. • At long time the time-dependent solution approaches to a power-law distribution in nonextensive statistics. • Numerically we have demonstrated the accuracy and validity of the time-dependent solution.« less
Diffusion of oxygen through cork stopper: is it a Knudsen or a Fickian mechanism?

PubMed

Lagorce-Tachon, Aurélie; Karbowiak, Thomas; Simon, Jean-Marc; Gougeon, Régis; Bellat, Jean-Pierre

2014-09-17

The aim of this work is to identify which law governs oxygen transfer through cork: Knudsen or Fickian mechanism. This is important to better understand wine oxidation during post-bottling aging. Oxygen transfer through cork wafers is measured at 298 K using a manometric permeation technique. Depending on the mechanism, we can extract the transport coefficients. Increasing the initial pressure of oxygen from 50 to 800 hPa leads to a change in the values of the transport coefficients. This implies that oxygen transport through cork does not obey the Knudsen law. From these results, we conclude that the limiting step of oxygen transport through cork occurs in the cell wall following Fickian law. From the diffusion dependence's coefficients with pressure, we also extract by applying transition state theory an apparent activation volume of 45 ± 4 nm(3). This high value indicates that oxygen molecules also diffuse from one site to another by passing through a gas phase.
Child passenger safety laws in the United States, 1978-2010: policy diffusion in the absence of strong federal intervention.

PubMed

Bae, Jin Yung; Anderson, Evan; Silver, Diana; Macinko, James

2014-01-01

This article examines the diffusion of U.S. state child passenger safety laws, analyzing over-time changes and inter-state differences in all identifiable features of laws that plausibly influence crash-related morbidity and mortality. The observed trend shows many states' continuing efforts to update their laws to be consistent with latest motor vehicle safety recommendations, with each state modifying their laws on average 6 times over the 30-year period. However, there has been a considerable time lag in knowledge diffusion and policy adoption. Even though empirical evidence supporting the protective effect of child restraint devices was available in the early 1970s, laws requiring their use were not adopted by all 50 states until 1986. For laws requiring minors to be seated in rear seats, the first state law adoption did not occur until two decades after the evidence became publicly available. As of 2010, only 12 states explicitly required the use of booster seats, 9 for infant seats and 6 for toddler seats. There is also great variation among states in defining the child population to be covered by the laws, the vehicle operators subject to compliance, and the penalties resulting from non-compliance. Some states cover only up to 4-year-olds while others cover children up to age 17. As of 2010, states have as many as 14 exemptions, such as those for non-residents, non-parents, commercial vehicles, large vehicles, or vehicles without seatbelts. Factors such as the complexity of the state of the science, the changing nature of guidelines (from age to height/weight-related criteria), and the absence of coordinated federal actions are potential explanations for the observed patterns. The resulting uneven policy landscape among states suggests a strong need for improved communication among state legislators, public health researchers, advocates and concerned citizen groups to promote more efficient and effective policymaking. Copyright © 2013 Elsevier Ltd. All rights reserved.
Child Passenger Safety Laws in the United States, 1978–2010: Policy Diffusion in the Absence of Strong Federal Intervention

PubMed Central

Bae, Jin Yung; Anderson, Evan; Silver, Diana; Macinko, James

2014-01-01

This article examines the diffusion of U.S. state child passenger safety laws, analyzing over-time changes and inter-state differences in all identifiable features of laws that plausibly influence crash-related morbidity and mortality. The observed trend shows many states’ continuing efforts to update their laws to be consistent with latest motor vehicle safety recommendations, with each state modifying their laws on average 6 times over the 30-year period. However, there has been a considerable time lag in knowledge diffusion and policy adoption. Even though empirical evidence supporting the protective effect of child restraint devices was available in the early 1970s, laws requiring their use were not adopted by all 50 states until 1986. For laws requiring minors to be seated in rear seats, the first state law adoption did not occur until two decades after the evidence became publicly available. As of 2010, only 12 states explicitly required the use of booster seats, 9 for infant seats and 6 for toddler seats. There is also great variation among states in defining the child population to be covered by the laws, the vehicle operators subject to compliance, and the penalties resulting from non-compliance. Some states cover only up to 4-year-olds while others cover children up to age 17. As of 2010, states have as many as 14 exemptions, such as those for non-residents, non-parents, commercial vehicles, large vehicles, or vehicles without seatbelts. Factors such as the complexity of the state of the science, the changing nature of guidelines (from age to height/weight-related criteria), and the absence of coordinated federal actions are potential explanations for the observed patterns. The resulting uneven policy landscape among states suggests a strong need for improved communication among state legislators, public health researchers, advocates and concerned citizen groups to promote more efficient and effective policymaking. PMID:24444836
A unified multicomponent stress-diffusion model of drug release from non-biodegradable polymeric matrix tablets.

PubMed

Salehi, Ali; Zhao, Jin; Cabelka, Tim D; Larson, Ronald G

2016-02-28

We propose a new transport model of drug release from hydrophilic polymeric matrices, based on Stefan-Maxwell flux laws for multicomponent transport. Polymer stress is incorporated in the total mixing free energy, which contributes directly to the diffusion driving force while leading to time-dependent boundary conditions at the tablet interface. Given that hydrated matrix tablets are dense multicomponent systems, extended Stefan-Maxwell (ESM) flux laws are adopted to ensure consistency with the Onsager reciprocity principle and the Gibbs-Duhem thermodynamic constraint. The ESM flux law for any given component takes into account the friction exerted by all other species and is invariant with respect to reference velocity, thus satisfying Galilean translational invariance. Our model demonstrates that penetrant-induced plasticization of polymer chains partially or even entirely offsets the steady decline of chemical potential gradients at the tablet-medium interface that drive drug release. Utilizing a Flory-Huggins thermodynamic model, a modified form of the upper convected Maxwell constitutive equation for polymer stress and a Fujita-type dependence of mutual diffusivities on composition, depending on parameters, Fickian, anomalous or case II drug transport arises naturally from the model, which are characterized by quasi-power-law release profiles with exponents ranging from 0.5 to 1, respectively. A necessary requirement for non-Fickian release in our model is that the matrix stress relaxation time is comparable to the time scale for water diffusion. Mutual diffusivities and their composition dependence are the most decisive factors in controlling drug release characteristics in our model. Regression of the experimental polymer dissolution and drug release profiles in a system of Theophylline/cellulose (K15M) demonstrate that API-water mutual diffusivity in the presence of excipient cannot generally be taken as a constant. Copyright © 2016 Elsevier B.V. All rights reserved.
Effect of upstream ULF waves on the energetic ion diffusion at the earth's foreshock: Theory, Simulation, and Observations

NASA Astrophysics Data System (ADS)

Otsuka, F.; Matsukiyo, S.; Kis, A.; Hada, T.

2017-12-01

Spatial diffusion of energetic particles is an important problem not only from a fundamental physics point of view but also for its application to particle acceleration processes at astrophysical shocks. Quasi-linear theory can provide the spatial diffusion coefficient as a function of the wave turbulence spectrum. By assuming a simple power-law spectrum for the turbulence, the theory has been successfully applied to diffusion and acceleration of cosmic rays in the interplanetary and interstellar medium. Near the earth's foreshock, however, the wave spectrum often has an intense peak, presumably corresponding to the upstream ULF waves generated by the field-aligned beam (FAB). In this presentation, we numerically and theoretically discuss how the intense ULF peak in the wave spectrum modifies the spatial parallel diffusion of energetic ions. The turbulence is given as a superposition of non-propagating transverse MHD waves in the solar wind rest frame, and its spectrum is composed of a piecewise power-law spectrum with different power-law indices. The diffusion coefficients are then estimated by using the quasi-linear theory and test particle simulations. We find that the presence of the ULF peak produces a concave shape of the diffusion coefficient when it is plotted versus the ion energy. The results above are used to discuss the Cluster observations of the diffuse ions at the Earth's foreshock. Using the density gradients of the energetic ions detected by the Cluster spacecraft, we determine the e-folding distances, equivalently, the spatial diffusion coefficients, of ions with their energies from 10 to 32 keV. The observed e-folding distances are significantly smaller than those estimated in the past statistical studies. This suggests that the particle acceleration at the foreshock can be more efficient than considered before. Our test particle simulation explains well the small estimate of the e-folding distances, by using the observed wave turbulence spectrum near the shock.
Power-laws in art

NASA Astrophysics Data System (ADS)

Etro, Federico; Stepanova, Elena

2018-09-01

We provide evidence of a cubic law of art prices that hints to a general pattern for the distribution of artistic talent. The persistence across heterogeneous markets from historical ones to contemporary art auctions of a power law in the distribution of the average price per artist suggests the possibility of a universal law for talent distribution. We explore scale-free networks of teacher-students to investigate the diffusion of talent over time.
Popping the balloon effect: assessing drug law enforcement in terms of displacement, diffusion, and the containment hypothesis.

PubMed

Windle, James; Farrell, Graham

2012-01-01

The "balloon effect" is an often used but rather dismissive representation of the effects of drug law enforcement. It implies a hydraulic displacement model and an impervious illicit drug trade. This paper reviews theoretical and empirical developments in policing and crime prevention. Based on this, 10 types of displacement are identified and four arguments developed: (1) Displacement is less extensive and harmful than often contended; (2) Where displacement may occur it preferably should be exploited as a policy tool to delay the illicit drug industry and deflect it to less harmful locations and forms; (3) The opposite of displacement occurs, termed a diffusion of drug control benefits, wherein law enforcement has benefits that extend further than envisaged, and has 10 types mirroring those of displacement; (4) The net impact of drug law enforcement is often underestimated, and a containment hypothesis may offer a more accurate framework for evaluation.
Generalized fractional diffusion equations for accelerating subdiffusion and truncated Lévy flights

NASA Astrophysics Data System (ADS)

Chechkin, A. V.; Gonchar, V. Yu.; Gorenflo, R.; Korabel, N.; Sokolov, I. M.

2008-08-01

Fractional diffusion equations are widely used to describe anomalous diffusion processes where the characteristic displacement scales as a power of time. For processes lacking such scaling the corresponding description may be given by diffusion equations with fractional derivatives of distributed order. Such equations were introduced in A. V. Chechkin, R. Gorenflo, and I. Sokolov [Phys. Rev. E 66, 046129 (2002)] for the description of the processes getting more anomalous in the course of time (decelerating subdiffusion and accelerating superdiffusion). Here we discuss the properties of diffusion equations with fractional derivatives of the distributed order for the description of anomalous relaxation and diffusion phenomena getting less anomalous in the course of time, which we call, respectively, accelerating subdiffusion and decelerating superdiffusion. For the former process, by taking a relatively simple particular example with two fixed anomalous diffusion exponents we show that the proposed equation effectively describes the subdiffusion phenomenon with diffusion exponent varying in time. For the latter process we demonstrate by a particular example how the power-law truncated Lévy stable distribution evolves in time to the distribution with power-law asymptotics and Gaussian shape in the central part. The special case of two different orders is characteristic for the general situation in which the extreme orders dominate the asymptotics.
Two-particle diffusion and locality assumption

NASA Astrophysics Data System (ADS)

Nicolleau, F.; Yu, G.

2004-07-01

A three-dimensional kinematic simulation (KS) model is used to study one- and two-particle diffusion in turbulent flows. The energy spectrum E(k) takes a power law form E(k)˜k-p. The value of this power p is varied from 1.2 to 3, so that its effects on the diffusion of one and two particles can be studied. The two-particle diffusion behaves differently depending on whether the two-particle separation is larger or smaller than the smallest scale of turbulence (Kolmogorov length scale η). When the two-particle mean square separation <Δ2(t)> is smaller than η2 it experiences a time exponential growth <Δ2(t)>=Δ02eγ(t/tη) but for a very short time. For longer times, when η2<<Δ2(t)>. In this inertial range we observe that d/dt<Δ2(t)>={a ln(<Δ(t)2>1/2/η)+b}u'L(η/L)(p+1)/2(<Δ(t)2>1/2/η)(p+1)/2 for p⩽3. For Δ0/η≫1 a=0, but a≠0 for Δ0/η⩽1 and as a consequence the pair diffusion cannot have lost its dependence on the initial separation during the exponential growth, i.e., γ is a function of Δ0/η. Our modified Richardson law is compared with two other proposed modifications to Richardson's power law, namely the virtual time [G. K. Batchelor, Proc. Cambridge Philos. Soc. 48, 345 (1952)] and the correction factor [F. Nicolleau and J. C. Vassilicos, Phys. Rev. Lett. 90, 245003 (2003)]. Further investigations on two-particle diffusion when p=3 give an excellent agreement with the experimental results in P. Morel and M. Larchevêque, J. Atmos. Sci. 31 (1974) for atmospheric turbulent flows. Finally, using two different combined power law energy spectra in KS, the isotropic small scales are found to have no significant role when their largest scale lT is less than 10 times the Kolmogorov length scale η.
[Dysfunctional resting-state connectivity of default mode network in adolescent patients with first-episode drug-naive major depressive disorder].

PubMed

Li, S Y; Zhu, Y; Wang, Y L; Lü, P P; Zuo, W B; Li, F Y

2017-12-05

Objective: To study resting-state functional connectivity (FC) of default mode network (DMN) in adolescent patients with first-episode drug-naive major depressive disorder (MDD). Methods: We enrolled thirty first-episode and drug-naive adolescent MDD patients and twenty-nine adolescent healthy control (HC) participants in the First Affiliated Hospital of Zhengzhou University. There were no differences in age, sex, and education between the MDD and HC group. Resting-state functional magnetic resonance images (fMRI) was performed. We selected posterior cingulate cortex (PCC) and medial prefrontal cortex (MPFC) of DMN as regions of interests (ROI). The differences of these regions from the whole brain functional connectivity were analyzed. The relations between abnormalities in FCs of DMN and clinical variables were further investigated. Results: Compared to the HCs, the MDD patients had congruently reduced FCs between the PCC and cerebellum, temporal cortices, occipital cortices, fusiform, dorsolateral prefrontal cortex. MPFC not only had reduced FCs with fusiform, temporal cortices, anterior cingulate cortex, but also had enhanced FCs with occipital cortices, parietal cortices, and precentral gyrus. In addition, the increased FC between the right MPFC and right precentral gyrus was positive correlated with Hamilton Rating Scale for Depression (HAMD) scores ( r =0.38, P =0.04). The reduced FC between the left middle temporal gyrus and left PCC as well as the enhanced FC between the right middle cingulum and right MPFC were positive correlated with the duration of depression since onset ( r =0.39, P =0.03; r =0.38, P =0.04). Conclusions: These findings show dysfunctional DMN connectivity of adolescent MDD patients. Neurodevelopmental abnormalities in DMN may present in adolescent MDD.
Covalent dye attachment influences the dynamics and conformational properties of flexible peptides

PubMed Central

Crevenna, Alvaro H.; Bomblies, Rainer; Lamb, Don C.

2017-01-01

Fluorescence spectroscopy techniques like Förster resonance energy transfer (FRET) and fluorescence correlation spectroscopy (FCS) have become important tools for the in vitro and in vivo investigation of conformational dynamics in biomolecules. These methods rely on the distance-dependent quenching of the fluorescence signal of a donor fluorophore either by a fluorescent acceptor fluorophore (FRET) or a non-fluorescent quencher, as used in FCS with photoinduced electron transfer (PET). The attachment of fluorophores to the molecule of interest can potentially alter the molecular properties and may affect the relevant conformational states and dynamics especially of flexible biomolecules like intrinsically disordered proteins (IDP). Using the intrinsically disordered S-peptide as a model system, we investigate the impact of terminal fluorescence labeling on the molecular properties. We perform extensive molecular dynamics simulations on the labeled and unlabeled peptide and compare the results with in vitro PET-FCS measurements. Experimental and simulated timescales of end-to-end fluctuations were found in excellent agreement. Comparison between simulations with and without labels reveal that the π-stacking interaction between the fluorophore labels traps the conformation of S-peptide in a single dominant state, while the unlabeled peptide undergoes continuous conformational rearrangements. Furthermore, we find that the open to closed transition rate of S-peptide is decreased by at least one order of magnitude by the fluorophore attachment. Our approach combining experimental and in silico methods provides a benchmark for the simulations and reveals the significant effect that fluorescence labeling can have on the conformational dynamics of small biomolecules, at least for inherently flexible short peptides. The presented protocol is not only useful for comparing PET-FCS experiments with simulation results but provides a strategy to minimize the influence on molecular properties when chosing labeling positions for fluorescence experiments. PMID:28542243
Phenotypic and molecular characteristics associated with various domains of quality of life in oncology patients and their family caregivers.

PubMed

Alexander, Kimberly E; Cooper, Bruce A; Paul, Steven M; Yates, Patsy; Aouizerat, Bradley E; Miaskowski, Christine

2016-11-01

Not all oncology patients and their family caregivers (FCs) experience the same quality of life (QOL). The purposes of this study were to identify latent classes of oncology patients (n = 168) and their FCs (n = 85) with distinct physical, psychological, social, and spiritual well-being trajectories from prior to through 4 months after the completion of radiation therapy and to evaluate for demographic, clinical, and genetic characteristics that distinguished between these latent classes. Using growth mixture modeling, two latent classes were found for three (i.e., physical, psychological, and social well-being) of the four QOL domains evaluated. Across these three domains, the largest percentage of participants reported relatively high well-being scores across the 6 months of the study. Across these three QOL domains, patients and FCs who were younger, female, belonged to an ethnic minority group, had children at home, had multiple comorbid conditions, or had a lower functional status, were more likely to be classified in the lower QOL class. The social well-being domain was the only domain that had a polymorphism in nuclear factor kappa beta 2 (NFKB2) associated with latent class membership. Carrying one or two doses of the rare allele for rs7897947 was associated with a 54 % decrease in the odds of belonging to the lower social well-being class [OR (95 % CI) = .46 (.21, .99), p = .049]. These findings suggest that a number of phenotypic and molecular characteristics contribute to differences in QOL in oncology patients and their FCs.
Modeling, materials, and metrics: the three-m approach to FCS signature solutions

NASA Astrophysics Data System (ADS)

Gonda, Teresa G.; Thomas, David J.; Namburu, Raju; Edwards, Timothy

2002-08-01

There is a push in the Army to develop lighter vehicles that can get to remote parts of the world quickly. This objective force is not some new vehicle, but a whole new way of fighting wars. The Future Combat System (FCS), as it is called, has an extremely aggressive timeline and must rely on modeling and simulation to aid in defining the goals, optimizing the design and materials, and testing the performance of the various FCS systems concepts. While virtual prototyping for vehicles (both military and commercial) has been around as a concept for well over a decade and its use is promoted heavily in tours and in boardrooms, the actual application of virtual protoyping is often limited and when successful has been confined to specific physical engineering areas such as weight, space, stress, mobility, and ergonomics. If FCS is to succeed in its acquisition schedule, virtual prototyping will have to be relied on heavily and its application expanded. Signature management is an example of an area that would benefit greatly from virtual prototyping tools. However, there are several obstacles to achieving this goal. To rigorously analyze a vehicle's IR and visual signatures extensively in several different environments over different weather and seasonal conditions could result millions of potentially unique signatures to evaluate. In addition, there is no real agreement on what evaluate means or even what value is used to represent signature; Delta T( degree(s)C), Probability of Detection? What the user really wants to know is: how do I make my system survivable? This paper attempts to describe and then bound the problem and describe how the Army is attempting to deal with some of these issues in a holistic manner using SMART (Simulation and Modeling for Acquisition, Requirements, and Training) principles.
Lipid droplet analysis using in vitro bovine oocytes and embryos.

PubMed

Ordoñez-Leon, E A; Merchant, H; Medrano, A; Kjelland, M; Romo, S

2014-04-01

The aim of this study was to quantify the content of lipid droplets in bovine oocytes and embryos from Bos indicus (Bi), Bos taurus (Bt) and Bos indicus × Bos taurus (Bi × Bt). Oocytes were aspirated post-mortem and subjected to in vitro maturation, in vitro fertilization and in vitro development; the medium employed at each stage (TCM-199, TALP, SOF) was supplemented with (i) serum replacement (SR), (ii) foetal calf serum (FCS) or (iii) oestrous cow serum (ECS). The structure and distribution of the lipid droplets were established using electron microscopy, but were quantified using an optical microscope on semi-fine toluidine blue-stained sections. The highest percentage of embryos corresponded to those produced with FCS and ECS, which differed from embryos generated with SR (p < 0.05). The highest percentage of morulae and the lowest percentage of blastocysts were obtained with the SR supplement (p < 0.05). The oocytes cultured in FCS demonstrated a higher number of lipid droplets compared to those cultured in SR and ECS (p < 0.05). Less accumulation of lipids was observed in embryos supplemented with SR. The lowest and highest numbers of lipid droplets in oocytes corresponded to the Bi and Bt strain, respectively. The lowest amount of lipid droplets in embryos was observed in Bi (p < 0.05). In conclusion, supplementation of the in vitro development culture medium (synthetic oviduct fluid) with a synthetic substitute serum produced similar results in terms of embryo development compared to those obtained with FCS, but a decreased degree of lipid droplet accumulation was observed in the in vitro-cultured embryos. © 2014 Blackwell Verlag GmbH.
Combined platelet and plasma derivatives enhance proliferation of stem/progenitor cells maintaining their differentiation potential.

PubMed

Muraglia, Anita; Todeschi, Maria Rosa; Papait, Andrea; Poggi, Alessandro; Spanò, Raffaele; Strada, Paolo; Cancedda, Ranieri; Mastrogiacomo, Maddalena

2015-12-01

Platelet derivatives have been proposed as alternatives to animal sera given that for cell therapy applications, the use of fetal bovine/calf serum (FBS/FCS) is subjected to severe limitations for safety and ethical concerns. We developed a cell culture medium additive obtained by the combination of two blood-derived standardized components. A platelet lysate (PL) and a platelet-poor plasma (PPP) were produced in a lyophilized form. Each component was characterized for its growth factor content (platelet-derived growth factor-BB/vascular endothelial growth factor). PL and PPP were used as single components or in combination in different ratio at cumulative 5% final concentration in the culture medium. The single components were less effective than the component combination. In primary cell cultures (bone marrow stromal cells, adipose derived adult stem cells, osteoblasts, chondrocytes, umbilical cord-derived mesenchymal stromal cells, lymphocytes), the PL/PPP supplement promoted an increased cell proliferation in respect to the standard FCS culture in a dose-dependent manner, maintaining the cell functionality, clonogenicity, phenotype and differentiative properties throughout the culture. At a different component ratio, the supplement was also used to support proliferation of a cell line (U-937). The PL/PPP supplement is an efficient cell culture medium additive that can replace FCS to promote cell proliferation. It can outdo FCS, especially when adopted in primary cultures from tissue biopsies. Moreover, the dual component nature of the supplement allows the researcher to determine the more appropriate ratio of the two components for the nutritional and functional requirements of the cell type of interest. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.
Exploring the structure of fucosylated chondroitin sulfate through bottom-up nuclear magnetic resonance and electrospray ionization-high-resolution mass spectrometry approaches.

PubMed

Santos, Gustavo Rc; Porto, Ana Co; Soares, Paulo Ag; Vilanova, Eduardo; Mourão, Paulo As

2017-07-01

Fucosylated chondroitin sulfate (FCS) from sea cucumbers is composed of a chondroitin sulfate (CS) central core and branches of sulfated fucose. The structure of this complex glycosaminoglycan is usually investigated via nuclear magnetic resonance (NMR) analyses of the intact molecule, ergo through a top-down approach, which often yield spectra with intricate sets of signals. Here we employed a bottom-up approach to analyze the FCSs from the sea cucumbers Isostichopus badionotus and Ludwigothurea grisea from their basic constituents, viz. CS cores and sulfated fucose branches, obtained via systematic fragmentation through mild acid hydrolysis. Oligosaccharides derived from the central CS core were analyzed via NMR spectroscopy and the disaccharides produced using chondroitin sulfate lyase via SAX-HPLC. The CS cores from the two species were similar, showing only slight differences in the proportions of 4- or 6-monosulfated and 4,6-disulfated β-d-GalNAc. Sulfated fucose units released from the FCSs were analyzed via NMR and ESI-HRMS spectroscopies. The fucose units from each species presented extensive qualitative differences, but quantitative assessments of these units were hindered, mostly because of their extensive desulfation during the hydrolysis. The bottom-up analysis performed here has proved useful to explore the structure of FCS through a sum-of-the-parts approach in a qualitative manner. We further demonstrate that under specific acidification conditions particular fucose branches can be removed preferentially from FCS. Preparation of derivatives enriched with particular fucose branches could be useful for studies on "structure vs. biological function" of FCS. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Dock mediates Scar- and WASp-dependent actin polymerization through interaction with cell adhesion molecules in founder cells and fusion-competent myoblasts.

PubMed

Kaipa, Balasankara Reddy; Shao, Huanjie; Schäfer, Gritt; Trinkewitz, Tatjana; Groth, Verena; Liu, Jianqi; Beck, Lothar; Bogdan, Sven; Abmayr, Susan M; Önel, Susanne-Filiz

2013-01-01

The formation of the larval body wall musculature of Drosophila depends on the asymmetric fusion of two myoblast types, founder cells (FCs) and fusion-competent myoblasts (FCMs). Recent studies have established an essential function of Arp2/3-based actin polymerization during myoblast fusion, formation of a dense actin focus at the site of fusion in FCMs, and a thin sheath of actin in FCs and/or growing muscles. The formation of these actin structures depends on recognition and adhesion of myoblasts that is mediated by cell surface receptors of the immunoglobulin superfamily. However, the connection of the cell surface receptors with Arp2/3-based actin polymerization is poorly understood. To date only the SH2-SH3 adaptor protein Crk has been suggested to link cell adhesion with Arp2/3-based actin polymerization in FCMs. Here, we propose that the SH2-SH3 adaptor protein Dock, like Crk, links cell adhesion with actin polymerization. We show that Dock is expressed in FCs and FCMs and colocalizes with the cell adhesion proteins Sns and Duf at cell-cell contact points. Biochemical data in this study indicate that different domains of Dock are involved in binding the cell adhesion molecules Duf, Rst, Sns and Hbs. We emphasize the importance of these interactions by quantifying the enhanced myoblast fusion defects in duf dock, sns dock and hbs dock double mutants. Additionally, we show that Dock interacts biochemically and genetically with Drosophila Scar, Vrp1 and WASp. Based on these data, we propose that Dock links cell adhesion in FCs and FCMs with either Scar- or Vrp1-WASp-dependent Arp2/3 activation.

Development and calibration of fine collimators for the ASTRO-H Soft Gamma-ray Detector

NASA Astrophysics Data System (ADS)

Mizuno, T.; Kimura, D.; Fukazawa, Y.; Furui, S.; Goto, K.; Hayashi, T.; Kawabata, K. S.; Kawano, T.; Kitamura, Y.; Shirakawa, H.; Tanabe, T.; Makishima, K.; Nakajima, K.; Nakazawa, K.; Fukuyama, T.; Ichinohe, Y.; Ishimura, K.; Ohta, M.; Sato, T.; Takahashi, T.; Uchida, Y.; Watanabe, S.; Ishibashi, K.; Sakanobe, K.; Matsumoto, H.; Miyazawa, T.; Mori, H.; Sakai, M.; Tajima, H.

2014-07-01

The Soft Gamma-ray Detector (SGD) is a Si/CdTe Compton telescope surrounded by a thick BGO active shield and is scheduled to be onboard the ASTRO-H satellite when it is launched in 2015. The SGD covers the energy range from 40 to 600 keV with high sensitivity, which allows us to study nonthermal phenomena in the universe. The SGD uses a Compton camera with the narrow field-of-view (FOV) concept to reduce the non-Xray background (NXB) and improve the sensitivity. Since the SGD is essentially a nonimaging instrument, it also has to cope with the cosmic X-ray background (CXB) within the FOV. The SGD adopts passive shields called "fine collimators" (FCs) to restrict the FOV to <= 0.6° for low-energy photons (<= 100 keV), which reduces contamination from CXB to less than what is expected due to NXB. Although the FC concept was already adopted by the Hard X-ray Detector onboard Suzaku, FCs for the SGD are about four times larger in size and are technically more difficult to operate. We developed FCs for the SGD and confirmed that the prototypes function as required by subjecting them to an X-ray test and environmental tests, such as vibration tests. We also developed an autocollimator system, which uses visible light to determine the transmittance and the optical axis, and calibrated it against data from the X-ray test. The acceptance tests of flight models started in December 2013: five out of six FCs were deemed acceptable, and one more unit is currently being produced. The activation properties were studied based on a proton-beam test and the results were used to estimate the in-orbit NXB.
Effect of alcohol on the structure of cytochrome C: FCS and molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Amin, Md. Asif; Halder, Ritaban; Ghosh, Catherine; Jana, Biman; Bhattacharyya, Kankan

2016-12-01

Effect of ethanol on the size and structure of a protein cytochrome C (Cyt C) is investigated using fluorescence correlation spectroscopy (FCS) and molecular dynamics (MD) simulations. For FCS studies, Cyt C is covalently labeled with a fluorescent probe, alexa 488. FCS studies indicate that on addition of ethanol, the size of the protein varies non-monotonically. The size of Cyt C increases (i.e., the protein unfolds) on addition of alcohol (ethanol) up to a mole fraction of 0.2 (44.75% v/v) and decreases at higher alcohol concentration. In order to provide a molecular origin of this structural transition, we explore the conformational free energy landscape of Cyt C as a function of radius of gyration (Rg) at different compositions of water-ethanol binary mixture using MD simulations. Cyt C exhibits a minimum at Rg ˜ 13 Å in bulk water (0% alcohol). Upon increasing ethanol concentration, a second minimum appears in the free energy surface with gradually larger Rg up to χEtOH ˜ 0.2 (44.75% v/v). This suggests gradual unfolding of the protein. At a higher concentration of alcohol (χEtOH > 0.2), the minimum at large Rg vanishes, indicating compaction. Analysis of the contact map and the solvent organization around protein indicates a preferential solvation of the hydrophobic residues by ethanol up to χEtOH = 0.2 (44.75% v/v) and this causes the gradual unfolding of the protein. At high concentration (χEtOH = 0.3 (58% v/v)), due to structural organization in bulk water-ethanol binary mixture, the extent of preferential solvation by ethanol decreases. This causes a structural transition of Cyt C towards a more compact state.
Correlation Structure of Fractional Pearson Diffusions.

PubMed

Leonenko, Nikolai N; Meerschaert, Mark M; Sikorskii, Alla

2013-09-01

The stochastic solution to a diffusion equations with polynomial coefficients is called a Pearson diffusion. If the first time derivative is replaced by a Caputo fractional derivative of order less than one, the stochastic solution is called a fractional Pearson diffusion. This paper develops an explicit formula for the covariance function of a fractional Pearson diffusion in steady state, in terms of Mittag-Leffler functions. That formula shows that fractional Pearson diffusions are long range dependent, with a correlation that falls off like a power law, whose exponent equals the order of the fractional derivative.
Probing site-exclusive binding of aqueous QDs and their organelle-dependent dynamics in live cells by single molecule spectroscopy.

PubMed

Dong, Chaoqing; Chowdhury, Basudev; Irudayaraj, Joseph

2013-05-21

Understanding the biophysical and chemical interactions of nanoprobes and their fate upon entering live cells is critical for developing fundamental insights related to intracellular diagnostics, drug delivery and targeting. In this article we report herein a single molecule analysis procedure to quantitate site-specific exclusive membrane binding of N-acetyl-L-cysteine (NAC)-capped cadmium telluride (CdTe) quantum dots (QDs) in A-427 lung carcinoma cells (k(eq) = 0.075 ± 0.011 nM(-1)), its relative intracellular distribution and dynamics using fluorescence correlation spectroscopy (FCS) combined with scanning confocal fluorescence lifetime imaging (FLIM). In particular, we demonstrate that the binding efficacy of QDs to the cell membrane is directly related to their size and the targeting of QDs to specific membrane sites is exclusive. We also show that QDs are efficiently internalized by endocytosis and enclosed within the endosome and organelle-dependent diffusion dynamics can be monitored in live cells.
Time-to-digital converter card for multichannel time-resolved single-photon counting applications

NASA Astrophysics Data System (ADS)

Tamborini, Davide; Portaluppi, Davide; Tisa, Simone; Tosi, Alberto

2015-03-01

We present a high performance Time-to-Digital Converter (TDC) card that provides 10 ps timing resolution and 20 ps (rms) timing precision with a programmable full-scale-range from 160 ns to 10 μs. Differential Non-Linearity (DNL) is better than 1.3% LSB (rms) and Integral Non-Linearity (INL) is 5 ps rms. Thanks to the low power consumption (400 mW) and the compact size (78 mm x 28 mm x 10 mm), this card is the building block for developing compact multichannel time-resolved instrumentation for Time-Correlated Single-Photon Counting (TCSPC). The TDC-card outputs the time measurement results together with the rates of START and STOP signals and the number of valid TDC conversions. These additional information are needed by many TCSPC-based applications, such as: Fluorescence Lifetime Imaging (FLIM), Time-of-Flight (TOF) ranging measurements, time-resolved Positron Emission Tomography (PET), single-molecule spectroscopy, Fluorescence Correlation Spectroscopy (FCS), Diffuse Optical Tomography (DOT), Optical Time-Domain Reflectometry (OTDR), quantum optics, etc.
Determination of optical band gap of powder-form nanomaterials with improved accuracy

NASA Astrophysics Data System (ADS)

Ahsan, Ragib; Khan, Md. Ziaur Rahman; Basith, Mohammed Abdul

2017-10-01

Accurate determination of a material's optical band gap lies in the precise measurement of its absorption coefficients, either from its absorbance via the Beer-Lambert law or diffuse reflectance spectrum via the Kubelka-Munk function. Absorption coefficients of powder-form nanomaterials calculated from absorbance spectrum do not match those calculated from diffuse reflectance spectrum, implying the inaccuracy of the traditional optical band gap measurement method for such samples. We have modified the Beer-Lambert law and the Kubelka-Munk function with proper approximations for powder-form nanomaterials. Applying the modified method for powder-form nanomaterial samples, both absorbance and diffuse reflectance spectra yield exactly the same absorption coefficients and therefore accurately determine the optical band gap.
von Neumann's Law: Theoretical and Microgravity Experimental Comparison for Coarsening Diffusion in Bubble Lattices

NASA Technical Reports Server (NTRS)

Noever, David A.

2000-01-01

The effects of gravity in influencing the theoretical limit for bubble lattice coarsening and aging behavior, otherwise called von Neumann's law, is examined theoretically and experimentally. Preliminary microgravity results will be discussed.
Gravity Effects in Diffusive Coarsening of Bubble Lattices: von Neumann's Law

NASA Technical Reports Server (NTRS)

Noever, David A.

2000-01-01

von Neumann modelled the evolution of two-dimensional soap froths as a purely diffusive phenomenon; the area growth of a given cell was found to depend only on the geometry of the bubble lattice. In the model, hexagons are stable, pentagons shrink and heptagons grow. The simplest equivalent to the area growth law is / approximately t(sub beta). The result depends on assuming (1) an incompressible gas; (2) bubble walls which meet at 120 deg and (3) constant wall thickness and curvature. Each assumption is borne out in experiments except the last one: bubble wall thickness between connecting cells varies in unit gravity because of gravity drainage. The bottom part of the soap membrane is thickened, the top part is thinned, such that gas diffusion across the membrane shows a complex dependence on gravity. As a result, experimental tests of von Neumann's law have been influenced by effects of gravity; fluid behavior along cell borders can give non-uniform wall thicknesses and thus alter the effective area and gas diffusion rates between adjacent bubbles. For area plotted as a function of time, Glazier (J.A. Glazier, S.P. Gross, and I. Stavans, Phys. Rev. A. 36, 306 (1987); J. Stavans, J.A, Glazier, Phys. Rev. Lett. 62, 1318 (1989).) suggest that in some cases their failure to observe von Neumann's predicted growth exponent ((sup beta)theor(sup =1; beta)exp(sup =0.70 + 0.10)) may have been the result of such "fluid drainage onto the lower glass plate". Additional experiments which varied plate spacing gave different beta exponents in a fashion consistent with this suggestion. During preliminary long duration experiments (approximately 100 h) aboard Spacelab-J, a low-gravity test of froth coarsening has examined (1) power law scaling of von Neumann's law (beta values) in the appropriate diffusive limits; (2) new bubble lattice dynamics such as greater fluid wetting behavior on froth membranes in low gravity; and (3) explicit relations for the gravity dependence of the second moment (or disorder parameter) governing the geometric spread in cell-sidedness around the mean of perfect hexagonal filling. By reducing the gravity-induced distortion in lattice wall thickness, the diffusion-limited regime of bubble coarsening becomes available for performing critical tests of network dynamics.

Army Science Board FY2000 Summer Study. Technical and Tactical Opportunities for Revolutionary Advances in Rapidly Deployable Joint Ground Forces in the 2015-2025 Era. Volume III: Information Dominance Panel Report

DTIC Science & Technology

2001-04-01

Information Dominance , Sustainment and Support, and Training. The study concludes: 1) the FCS concept is sound, but senior level attention is required to ensure technologies are ready for 2006 FCS EMD; and 2) Key technologies will significantly improve force projection and combat power. The Information Dominance Panel was tasked to: 1) Assess required sensors at National and Theater level; 2) Assess the technological opportunity to provide necessary bandwidth for data, voice and video requirements; 3) Ascertain the requirements to deny the threat
FCS Technology Investigation Overview

NASA Technical Reports Server (NTRS)

Budinger, James; Gilbert, Tricia

2007-01-01

This working paper provides an overview of the Future Communication Study (FCS) technology investigation progress. It includes a description of the methodology applied to technology evaluation; evaluation criteria; and technology screening (down select) results. A comparison of screening results with other similar technology screening activities is provided. Additional information included in this working paper is a description of in-depth studies (including characterization of the L-band aeronautical channel; L-band deployment cost assessment; and performance assessments of candidate technologies in the applicable aeronautical channel) that have been conducted to support technology evaluations. The paper concludes with a description on-going activities leading to conclusion of the technology investigation and the development of technology recommendations.
A design procedure for the handling qualities optimization of the X-29A aircraft

NASA Technical Reports Server (NTRS)

Bosworth, John T.; Cox, Timothy H.

1989-01-01

The techniques used to improve the pitch-axis handling qualities of the X-29A wing-canard-planform fighter aircraft are reviewed. The aircraft and its FCS are briefly described, and the design method, which works within the existing FCS architecture, is characterized in detail. Consideration is given to the selection of design goals and design variables, the definition and calculation of the cost function, the validation of the mathematical model on the basis of flight-test data, and the validation of the improved design by means of nonlinear simulations. Flight tests of the improved design are shown to verify the simulation results.
Three-dimensional architecture of ribosomal DNA within barley nucleoli revealed with electron microscopy.

PubMed

Iwano, Megumi; Che, Fang-Sik; Takayama, Seiji; Fukui, Kiichi; Isogai, Akira

2003-01-01

To elucidate the topological positioning of ribosomal RNA genes (rDNA) and nucleolar structure in three dimensions, we examined the localization of rDNA using in situ hybridization (ISH) analysis by scanning electron microscopy (SEM). The rDNA genes within the three-dimensional architecture of nucleoli were detected on chromatin fibers that connect a thick strand-like structure and a protrusion of rDNA into the inner nuclear hole where the nucleolus is formed. This novel use of ISH together with SEM is useful for the analysis of nucleolar structure in detail. Furthermore, rDNA was detected at the periphery of the fibrillar centers (FCs) of the nucleolus using immuno-gold labeling together with transmission electron microscopy (TEM). In situ hybridization with TEM confirmed that rDNA is naked and thus active in the FCs of nucleoli; ISH with SEM confirmed that rDNA is not covered with ribonucleo proteins at the protruding point and is thus inactive. We also show that the distribution pattern of FCs differs from sample to sample. These results indicate that rDNA is transcribed dynamically in a time- and region-specific manner over the course of the cell cycle.
A novel composite adaptive flap controller design by a high-efficient modified differential evolution identification approach.

PubMed

Li, Nailu; Mu, Anle; Yang, Xiyun; Magar, Kaman T; Liu, Chao

2018-05-01

The optimal tuning of adaptive flap controller can improve adaptive flap control performance on uncertain operating environments, but the optimization process is usually time-consuming and it is difficult to design proper optimal tuning strategy for the flap control system (FCS). To solve this problem, a novel adaptive flap controller is designed based on a high-efficient differential evolution (DE) identification technique and composite adaptive internal model control (CAIMC) strategy. The optimal tuning can be easily obtained by DE identified inverse of the FCS via CAIMC structure. To achieve fast tuning, a high-efficient modified adaptive DE algorithm is proposed with new mutant operator and varying range adaptive mechanism for the FCS identification. A tradeoff between optimized adaptive flap control and low computation cost is successfully achieved by proposed controller. Simulation results show the robustness of proposed method and its superiority to conventional adaptive IMC (AIMC) flap controller and the CAIMC flap controllers using other DE algorithms on various uncertain operating conditions. The high computation efficiency of proposed controller is also verified based on the computation time on those operating cases. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Martínez Díez, Ana Luisa, E-mail: a.martinez@itma.es; Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg; Gutmann, Johannes

In this paper, we present a concentrator system based on a stack of fluorescent concentrators (FCs) and a bifacial solar cell. Coupling bifacial solar cells to a stack of FCs increases the performance of the system and preserves its efficiency when scaled. We used an approach to optimize a fluorescent solar concentrator system design based on a stack of multiple fluorescent concentrators (FC). Seven individual fluorescent collectors (20 mm×20 mm×2 mm) were realized by in-situ polymerization and optically characterized in regard to their ability to guide light to the edges. Then, an optimization procedure based on the experimental data ofmore » the individual FCs was carried out to determine the stack configuration that maximizes the total number of photons leaving edges. Finally, two fluorescent concentrator systems were realized by attaching bifacial silicon solar cells to the optimized FC stacks: a conventional system, where FC were attached to one side of the solar cell as a reference, and the proposed bifacial configuration. It was found that for the same overall FC area, the bifacial configuration increases the short-circuit current by a factor of 2.2, which is also in agreement with theoretical considerations.« less
Application of recombinant Pediococcus acidilactici BD16 (fcs⁺/ech⁺) in malolactic fermentation.

PubMed

Kaur, Baljinder; Kumar, Balvir; Kaur, Gaganjot; Chakraborty, Debkumar; Kaur, Kiranjeet

2015-04-01

This study was conducted to enhance flavor characteristics of wine by malolactic fermentation using recombinant Pediococcus acidilactici BD16 (fcs (+)/ech (+)) encoding synthetic genes of feruloyl-CoA synthetase and enoyl-CoA hydratase. After malolactic fermentation, wine phenolics were characterized using LCMS-ESI technique and a significant improvement in the antioxidant activity and flavor characteristics of wine was observed due to increased concentration of cinnamic acid derivatives. This proof of concept study highlights the role of recombinant P. acidilactici BD16 (fcs (+)/ech (+)) in improving flavor as well as aroma of wine due to production of several phenolic derivatives during secondary fermentation. A novel metabolic pathway was predicted from mass spectral analysis data that indicates biotransformation of cinnamic acid and derivatives into apigenin, catechin, coniferyl aldehyde, cyanidin, hydroxybenzoic acids, laricitrin, luteolin, malvidin 3-glucoside, myricetin, naringenin, pelargonin, piceatannol, querecitin, and vanillin that not only increased the overall consumer appreciation but also improved nutritional and probably the therapeutic properties of wines. This is a first evidence-based study where role of recombinant P. acidilactici BD16 (fcs (+)/ech (+)) in the wine secondary fermentation has been elucidated.
Fluorescent Metal-Organic Framework (MOF) as a Highly Sensitive and Quickly Responsive Chemical Sensor for the Detection of Antibiotics in Simulated Wastewater.

PubMed

Zhu, Xian-Dong; Zhang, Kun; Wang, Yu; Long, Wei-Wei; Sa, Rong-Jian; Liu, Tian-Fu; Lü, Jian

2018-02-05

A Zn(II)-based fluorescent metal-organic framework (MOF) was synthesized and applied as a highly sensitive and quickly responsive chemical sensor for antibiotic detection in simulated wastewater. The fluorescent chemical sensor, denoted FCS-1, exhibited enhanced fluorescence derived from its highly ordered, 3D MOF structure as well as excellent water stability in the practical pH range of simulated antibiotic wastewater (pH = 3.0-9.0). Remarkably, FCS-1 was able to effectively detect a series of sulfonamide antibiotics via photoinduced electron transfer that caused detectable fluorescence quenching, with fairly low detection limits. Two influences impacting measurements related to wastewater treatment and water quality monitoring, the presence of heavy-metal ions and the pH of solutions, were studied in terms of fluorescence quenching, which was nearly unaffected in sulfonamide-antibiotic detection. Additionally, the effective detection of sulfonamide antibiotics was rationalized by the theoretical computation of the energy bands of sulfonamide antibiotics, which revealed a good match between the energy bands of FCS-1 and sulfonamide antibiotics, in connection with fluorescence quenching in this system.
Full counting statistics of conductance for disordered systems

NASA Astrophysics Data System (ADS)

Fu, Bin; Zhang, Lei; Wei, Yadong; Wang, Jian

2017-09-01

Quantum transport is a stochastic process in nature. As a result, the conductance is fully characterized by its average value and fluctuations, i.e., characterized by full counting statistics (FCS). Since disorders are inevitable in nanoelectronic devices, it is important to understand how FCS behaves in disordered systems. The traditional approach dealing with fluctuations or cumulants of conductance uses diagrammatic perturbation expansion of the Green's function within coherent potential approximation (CPA), which is extremely complicated especially for high order cumulants. In this paper, we develop a theoretical formalism based on nonequilibrium Green's function by directly taking the disorder average on the generating function of FCS of conductance within CPA. This is done by mapping the problem into higher dimensions so that the functional dependence of generating a function on the Green's function becomes linear and the diagrammatic perturbation expansion is not needed anymore. Our theory is very simple and allows us to calculate cumulants of conductance at any desired order efficiently. As an application of our theory, we calculate the cumulants of conductance up to fifth order for disordered systems in the presence of Anderson and binary disorders. Our numerical results of cumulants of conductance show remarkable agreement with that obtained by the brute force calculation.
Human Factors Considerations for Safe Recovery from Faults In Flight Control Systems

NASA Technical Reports Server (NTRS)

Pritchett, Amy; Belcastro, C. M. (Technical Monitor)

2003-01-01

It is now possible - and important - to develop systems to help resolve Flight Control System (FCS) faults. From a human factors viewpoint, it is imperative that these systems take on roles, and provide functions, that are the most supportive to the pilot, given the stress, time pressure and workload they may experience following a FCS fault. FCS fault recovery systems may provide several different functions, including alerting, control assistance, and decision aiding. The biggest human factors questions are in the role suitable for the technology, and its specific functioning to achieve that role. Specifically, for these systems to be effective, they must meet the fundamental requirements that (1) they alert pilots to problems early enough that the pilot can reasonably resolve the fault and regain control of the aircraft and that (2) if the aircraft s handling qualities are severely degraded the HMS provide the appropriate stability augmentation to help the pilot stabilize and control the aircraft. This project undertook several research steps to develop such systems, focusing on the capabilities of pilots and on realistically attainable technologies. The ability to estimate which functions are the most valuable will help steer system development in the directions that can establish the highest safety levels.
3-D vision and figure-ground separation by visual cortex.

PubMed

Grossberg, S

1994-01-01

A neural network theory of three-dimensional (3-D) vision, called FACADE theory, is described. The theory proposes a solution of the classical figure-ground problem for biological vision. It does so by suggesting how boundary representations and surface representations are formed within a boundary contour system (BCS) and a feature contour system (FCS). The BCS and FCS interact reciprocally to form 3-D boundary and surface representations that are mutually consistent. Their interactions generate 3-D percepts wherein occluding and occluded object parts are separated, completed, and grouped. The theory clarifies how preattentive processes of 3-D perception and figure-ground separation interact reciprocally with attentive processes of spatial localization, object recognition, and visual search. A new theory of stereopsis is proposed that predicts how cells sensitive to multiple spatial frequencies, disparities, and orientations are combined by context-sensitive filtering, competition, and cooperation to form coherent BCS boundary segmentations. Several factors contribute to figure-ground pop-out, including: boundary contrast between spatially contiguous boundaries, whether due to scenic differences in luminance, color, spatial frequency, or disparity; partially ordered interactions from larger spatial scales and disparities to smaller scales and disparities; and surface filling-in restricted to regions surrounded by a connected boundary. Phenomena such as 3-D pop-out from a 2-D picture, Da Vinci stereopsis, 3-D neon color spreading, completion of partially occluded objects, and figure-ground reversals are analyzed. The BCS and FCS subsystems model aspects of how the two parvocellular cortical processing streams that join the lateral geniculate nucleus to prestriate cortical area V4 interact to generate a multiplexed representation of Form-And-Color-And-DEpth, or FACADE, within area V4. Area V4 is suggested to support figure-ground separation and to interact with cortical mechanisms of spatial attention, attentive object learning, and visual search. Adaptive resonance theory (ART) mechanisms model aspects of how prestriate visual cortex interacts reciprocally with a visual object recognition system in inferotemporal (IT) cortex for purposes of attentive object learning and categorization. Object attention mechanisms of the What cortical processing stream through IT cortex are distinguished from spatial attention mechanisms of the Where cortical processing stream through parietal cortex. Parvocellular BCS and FCS signals interact with the model What stream. Parvocellular FCS and magnocellular motion BCS signals interact with the model Where stream.(ABSTRACT TRUNCATED AT 400 WORDS)
Inhibition of proteinase 3 (PR3) by suramin and fetal calf serum (FCS): effect of PR3 and suramin on Chinese hamster ovary cells (CHO-cells).

PubMed

Karam, Gholamreza Asadi; Rasaee, Mohammad Javad; Mahmoodi, Mehdi; Khaksari, Mohammad

2005-07-01

Proteinase 3 (PR3) is a lysosomal protease that is stored in azurophilic granules neutrophilic granulocytes and monocytes. A number of inhibitors for this proteinase are reported. Comprehensive studies on the inhibitory effect of suramin and heat treated fetal calf serum (deltaFCS) on PR3 have not been reported. It has been reported that PR3 is able to destroy the cytoskeletal integral proteins, but we have not find any reports which showed the effect of this protease on Chinese hamster ovary cells (CHO-cells) in culture medium. Suramin has proven to be useful as an antitumor drug, but there was not any report on the effect of suramin on CHO-cells. The effects of various concentrations of deltaFCS (from 0.5% up to 10%) and suramin (from 0.8 microM up to 100 microM) on PR3 and different concentrations of suramin (from 0.8 microM up to 1000 microM) on CHO-cells were investigated. Data analysis were performed by, Kolmogorov-Smirnov test, ANOVA test and Tukey HSD post tests. Results showed that deltaFCS and suramin have an inhibitory effect on PR3 and these effects increased with increasing the concentration significantly (p < 0.01). PR3 with the concentration of 2.2 Unit/ml has no effect on CHO-cells. Although suramin with the concentration of less than 125 microM cell growth retarded for only a few hours, but with the concentration of 125 to 250 microM inhibit the cell growth for a week, and after that cells gain normal growth gradually. Suramin with concentration of more than 500 microM inhibited the cell growth completely. Although suramin reversibly inhibit the PR3 activity but in concentration of less than 250 microM it had no long-term effect on CHO-cells. Therefore it can be used in the investigation of proteases. There were unknown components in deltaFCS, which cause the inhibition of PR3 activity. This finding is very important in PR3 production in culture medium. However CHO-cells are resistant to PR3 and suramin in low concentration.

Diagnosing Autism Spectrum Disorder from Brain Resting-State Functional Connectivity Patterns Using a Deep Neural Network with a Novel Feature Selection Method.

PubMed

Guo, Xinyu; Dominick, Kelli C; Minai, Ali A; Li, Hailong; Erickson, Craig A; Lu, Long J

2017-01-01

The whole-brain functional connectivity (FC) pattern obtained from resting-state functional magnetic resonance imaging data are commonly applied to study neuropsychiatric conditions such as autism spectrum disorder (ASD) by using different machine learning models. Recent studies indicate that both hyper- and hypo- aberrant ASD-associated FCs were widely distributed throughout the entire brain rather than only in some specific brain regions. Deep neural networks (DNN) with multiple hidden layers have shown the ability to systematically extract lower-to-higher level information from high dimensional data across a series of neural hidden layers, significantly improving classification accuracy for such data. In this study, a DNN with a novel feature selection method (DNN-FS) is developed for the high dimensional whole-brain resting-state FC pattern classification of ASD patients vs. typical development (TD) controls. The feature selection method is able to help the DNN generate low dimensional high-quality representations of the whole-brain FC patterns by selecting features with high discriminating power from multiple trained sparse auto-encoders. For the comparison, a DNN without the feature selection method (DNN-woFS) is developed, and both of them are tested with different architectures (i.e., with different numbers of hidden layers/nodes). Results show that the best classification accuracy of 86.36% is generated by the DNN-FS approach with 3 hidden layers and 150 hidden nodes (3/150). Remarkably, DNN-FS outperforms DNN-woFS for all architectures studied. The most significant accuracy improvement was 9.09% with the 3/150 architecture. The method also outperforms other feature selection methods, e.g., two sample t -test and elastic net. In addition to improving the classification accuracy, a Fisher's score-based biomarker identification method based on the DNN is also developed, and used to identify 32 FCs related to ASD. These FCs come from or cross different pre-defined brain networks including the default-mode, cingulo-opercular, frontal-parietal, and cerebellum. Thirteen of them are statically significant between ASD and TD groups (two sample t -test p < 0.05) while 19 of them are not. The relationship between the statically significant FCs and the corresponding ASD behavior symptoms is discussed based on the literature and clinician's expert knowledge. Meanwhile, the potential reason of obtaining 19 FCs which are not statistically significant is also provided.
Design and evaluation of a field study on the contamination of selected volatile organic compounds and wastewater-indicator compounds in blanks and groundwater samples

USGS Publications Warehouse

Thiros, Susan A.; Bender, David A.; Mueller, David K.; Rose, Donna L.; Olsen, Lisa D.; Martin, Jeffrey D.; Bernard, Bruce; Zogorski, John S.

2011-01-01

The Field Contamination Study (FCS) was designed to determine the field processes that tend to result in clean field blanks and to identify potential sources of contamination to blanks collected in the field from selected volatile organic compounds (VOCs) and wastewater-indicator compounds (WICs). The VOCs and WICs analyzed in the FCS were detected in blanks collected by the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program during 1996–2008 and 2002–08, respectively. To minimize the number of variables, the study required ordering of supplies just before sampling, storage of supplies and equipment in clean areas, and use of adequate amounts of purge-and-trap volatile-grade methanol and volatile pesticide-grade blank water (VPBW) to clean sampling equipment and to collect field blanks.Blanks and groundwater samples were collected during 2008–09 at 16 sites, which were a mix of water-supply and monitoring wells, located in 9 States. Five different sample types were collected for the FCS at each site: (1) a source-solution blank collected at the USGS National Water Quality Laboratory (NWQL) using laboratory-purged VPBW, (2) source-solution blanks collected in the field using laboratory-purged VPBW, (3) source-solution blanks collected in the field using field-purged VPBW, (4) a field blank collected using field-purged VPBW, and (5) a groundwater sample collected from a well. The source-solution blank and field-blank analyses were used to identify, quantify, and document extrinsic contamination and to help determine the sources and causes of data-quality problems that can affect groundwater samples.Concentrations of compounds detected in FCS analyses were quantified and results were stored in the USGS National Water Information System database after meeting rigorous identification and quantification criteria. The study also utilized information provided by laboratory analysts about evidence indicating the presence of selected compounds, using less rigorous identification criteria than is required for reporting data to the National Water Information System database. For the FCS, these data are considered adequate to indicate "evidence of presence," and were used only for diagnostic purposes. Evidence of VOCs and WICs at low concentrations near or less than the long-term method detection level can indicate a contamination problem that could affect future datasets if method detection levels were ever to be lowered.
Detection of substrate binding of a collagen-specific molecular chaperone HSP47 in solution using fluorescence correlation spectroscopy.

PubMed

Kitamura, Akira; Ishida, Yoshihito; Kubota, Hiroshi; Pack, Chan-Gi; Homma, Takayuki; Ito, Shinya; Araki, Kazutaka; Kinjo, Masataka; Nagata, Kazuhiro

2018-02-26

Heat shock protein 47 kDa (HSP47), an ER-resident and collagen-specific molecular chaperone, recognizes collagenous hydrophobic amino acid sequences (Gly-Pro-Hyp) and assists in secretion of correctly folded collagen. Elevated collagen production is correlated with HSP47 expression in various diseases, including fibrosis and keloid. HSP47 knockdown ameliorates liver fibrosis by inhibiting collagen secretion, and inhibition of the interaction of HSP47 with procollagen also prevents collagen secretion. Therefore, a high-throughput system for screening of drugs capable of inhibiting the interaction between HSP47 and collagen would aid the development of novel therapies for fibrotic diseases. In this study, we established a straightforward method for rapidly and quantitatively measuring the interaction between HSP47 and collagen in solution using fluorescence correlation spectroscopy (FCS). The diffusion rate of HSP47 labeled with Alexa Fluor 488 (HSP47-AF), a green fluorescent dye, decreased upon addition of type I or III collagen, whereas that of dye-labeled protein disulfide isomerase (PDI) or bovine serum albumin (BSA) did not, indicating that specific binding of HSP47 to collagen could be detected using FCS. Using this method, we calculated the dissociation constant of the interaction between HSP47 and collagen. The binding ratio between HSP47-AF and collagen did not change in the presence of sodium chloride, confirming that the interaction was hydrophobic in nature. In addition, we observed dissociation of collagen from HSP47 at low pH and re-association after recovery to neutral pH. These observations indicate that this system is appropriate for detecting the interaction between HSP47 and collagen, and could be applied to high-throughput screening for drugs capable of suppressing and/or curing fibrosis. Copyright © 2018 Elsevier Inc. All rights reserved.
A stability analysis of the power-law steady state of marine size spectra.

PubMed

Datta, Samik; Delius, Gustav W; Law, Richard; Plank, Michael J

2011-10-01

This paper investigates the stability of the power-law steady state often observed in marine ecosystems. Three dynamical systems are considered, describing the abundance of organisms as a function of body mass and time: a "jump-growth" equation, a first order approximation which is the widely used McKendrick-von Foerster equation, and a second order approximation which is the McKendrick-von Foerster equation with a diffusion term. All of these yield a power-law steady state. We derive, for the first time, the eigenvalue spectrum for the linearised evolution operator, under certain constraints on the parameters. This provides new knowledge of the stability properties of the power-law steady state. It is shown analytically that the steady state of the McKendrick-von Foerster equation without the diffusion term is always unstable. Furthermore, numerical plots show that eigenvalue spectra of the McKendrick-von Foerster equation with diffusion give a good approximation to those of the jump-growth equation. The steady state is more likely to be stable with a low preferred predator:prey mass ratio, a large diet breadth and a high feeding efficiency. The effects of demographic stochasticity are also investigated and it is concluded that these are likely to be small in real systems.
Anomalous Oxidative Diffusion in Titanium Pyrotechnic Powders

DOE PAGES

Erikson, William W.; Coker, Eric N.

2016-11-10

It has long been observed that oxidation processes in metals tend to follow a parabolic rate law associated with the growth of a surface oxide layer. Here we observe that for certain titanium powders, the expected parabolic law (∝t 1/2) is recovered, yet for others, the exponent differs significantly. One explanation for this non-parabolic, anomalous diffusion arises from fractal geometry. Theoretical considerations indicate that the time response of diffusion-limited processes in an object closely follow a power-law in time (t n) with n=(E–D)/2, where E is the object's Euclidean dimension and D is its boundary's Hausdorff dimension. Non-integer, (fractal) valuesmore » of D will result in n≠1/2. Finite element simulations of several canonical fractal objects were performed to verify the application of this theory; the results matched the theory well. Two different types of titanium powder were tested in isothermal thermogravimetric tests under dilute oxygen. Time-dependent mass uptake data were fit with power-law forms and the associated exponents were used to determine an equivalent fractal dimension. One Ti powder type has an implied surface dimension of ca. 2.3 to 2.5, suggesting fractal geometry may be operative. Finally, the other has a dimension near 2.0, indicating it behaves like traditional material.« less
Are Law Schools Poised for Innovation? Three Case Studies of Law Professors Teaching Online in American J.D. Programs

ERIC Educational Resources Information Center

Jaworowski, Susan

2013-01-01

The purpose of this qualitative case study is to describe the characteristics of three law professors teaching online courses to determine what type of adopter they were. This study used the Rogers diffusion of innovation theory, and specifically analyzed the participants on whether they were innovators or early adopters. These analyses are…
Dispersion effects in the miscible displacement of two fluids in a duct of large aspect ratio

NASA Astrophysics Data System (ADS)

Zhang, J.; Frigaard, I. A.

We study miscible displacements in long ducts in the dispersive limit of small \\varepsilon Pe, where \\varepsilon ≪ 1 is the inverse aspect ratio and Pe the Péclet number. We consider the class of generalized Newtonian fluids, with specified closure laws for the fluid properties of the concentration-dependent mixture. Regardless of viscosity ratio and the constitutive laws of the pure fluids, for sufficiently small \\varepsilon Pe these displacements are characterized by rapid cross-stream diffusion and slow streamwise dispersion, i.e. the concentration appears to be near-uniform across the duct and spreads slowly as it translates. Using the multiple-scales method we derive the leading-order asymptotic approximation to the average fluid concentration bar{c}_0. We show that bar{c}_0 evolves on the slow timescale t ˜ (\\varepsilon Pe)^{-1}, and satisfies a nonlinear diffusion equation in a frame of reference moving with the mean speed of the flow. In the case that the two fluids have identical rheologies and the concentration represents a passive tracer, the diffusion equation is linear. For Newtonian fluids we recover the classical results of Taylor (l953), Aris (1956), and for power-law fluids those of Vartuli et al. (1995). In the case that the fluids differ and/or that mixing is non-passive, bar{c}_0 satisfies a nonlinear diffusion equation in the moving frame of reference. Given a specific mixing/closure law for the rheological properties, we are able to compute the dispersive diffusivity D_T(bar{c}_0) and predict spreading along the channel. We show that D_T(bar{c}_0) can vary significantly with choice of mixing law and discuss why. This also opens the door to possibilities of controlling streamwise spreading by the rheological design of reactive mixtures, i.e. including chemical additives such that the rheology of the mixture behaves very differently to the rheology of either pure fluid. Computed examples illustrate the potential effects that might be achieved.
The effect of propofol on plasma membrane ultrastructure in the intact cells

NASA Astrophysics Data System (ADS)

Jin, Weixiang; Pralle, Arnd

The mechanism of general anesthesia is still unknown. One drug used for human anesthesia, propofol, has been shown to interact with some ligand gated ion-channels, but also easily dissolves in the lipid bilayer and alters fluidity. Which mechanism dominates or even how anesthesia arises are unclear. We study the influence of propofol on plasma membrane (PM) ultrastructure in intact cells. In the PM, transient submicroscopic nanodomains form by interactions between lipid-acyl-chains or lipid head groups, stabilized by cholesterol. In addition, membrane cytoskeleton further regulates the nanodomains, which then regulate signaling. We study transient propofol effects on these domains from low to clinically relevant propofol concentrations by analyzing diffusion of GFP-tagged outer leaflet/inner leaflet membrane proteins. Using bimFCS we measure diffusion on multiple length scales simultaneously. We observe that at low propofol concentrations, the nanodomains trap GPI-mGFP less, consistent with studies showing that propofol decreases the phase transition temperature of membrane derived vesicles. Interestingly, at clinical relevant concentrations of propofol, the nanodomains trap GPI-mGFP more strongly. This is only observed at 37C. By inhibiting myosin activity or actin filaments (de-)polymerization, we find that the activity of actin filaments further alters the behavior of cholesterol nanodomains due to propofol. We compare the effect of propofol and its analog confirming specificity.
Transient in-plane thermal transport in nanofilms with internal heating

PubMed Central

Cao, Bing-Yang

2016-01-01

Wide applications of nanofilms in electronics necessitate an in-depth understanding of nanoscale thermal transport, which significantly deviates from Fourier's law. Great efforts have focused on the effective thermal conductivity under temperature difference, while it is still ambiguous whether the diffusion equation with an effective thermal conductivity can accurately characterize the nanoscale thermal transport with internal heating. In this work, transient in-plane thermal transport in nanofilms with internal heating is studied via Monte Carlo (MC) simulations in comparison to the heat diffusion model and mechanism analyses using Fourier transform. Phonon-boundary scattering leads to larger temperature rise and slower thermal response rate when compared with the heat diffusion model based on Fourier's law. The MC simulations are also compared with the diffusion model with effective thermal conductivity. In the first case of continuous internal heating, the diffusion model with effective thermal conductivity under-predicts the temperature rise by the MC simulations at the initial heating stage, while the deviation between them gradually decreases and vanishes with time. By contrast, for the one-pulse internal heating case, the diffusion model with effective thermal conductivity under-predicts both the peak temperature rise and the cooling rate, so the deviation can always exist. PMID:27118903
Transient in-plane thermal transport in nanofilms with internal heating.

PubMed

Hua, Yu-Chao; Cao, Bing-Yang

2016-02-01

Wide applications of nanofilms in electronics necessitate an in-depth understanding of nanoscale thermal transport, which significantly deviates from Fourier's law. Great efforts have focused on the effective thermal conductivity under temperature difference, while it is still ambiguous whether the diffusion equation with an effective thermal conductivity can accurately characterize the nanoscale thermal transport with internal heating. In this work, transient in-plane thermal transport in nanofilms with internal heating is studied via Monte Carlo (MC) simulations in comparison to the heat diffusion model and mechanism analyses using Fourier transform. Phonon-boundary scattering leads to larger temperature rise and slower thermal response rate when compared with the heat diffusion model based on Fourier's law. The MC simulations are also compared with the diffusion model with effective thermal conductivity. In the first case of continuous internal heating, the diffusion model with effective thermal conductivity under-predicts the temperature rise by the MC simulations at the initial heating stage, while the deviation between them gradually decreases and vanishes with time. By contrast, for the one-pulse internal heating case, the diffusion model with effective thermal conductivity under-predicts both the peak temperature rise and the cooling rate, so the deviation can always exist.
Unexpected consequences of bedload diffusion

NASA Astrophysics Data System (ADS)

Devauchelle, O.; Abramian, A.; Lajeunesse, E.

2017-12-01

Sedimentary grains transported as bedload bump and bounce on the rough bed of the river that entrains them. The succession of these random events causes bedload particles to diffuse across the flow, towards the less active areas of the bed. In a fashion reminiscent of that proposed by Parker (1978) for suspended load, this mechanism opposes gravity to maintain the banks of alluvial rivers. In fact, diffusion is so tightly linked to bedload that it appears in the most basic sediment transport experiment--the straight channel we use to calibrate transport laws. Indeed, the fixed sides of the channel cause the flow, and thus the bed shear stress, to vary across the flume. This variation induces bedload diffusion, which in turn deforms the bed. As a consequence, to reliably calibrate a transport law, we need to measure the full profiles of shear stress and bedload transport, rather than bulk-average these quantities. Unfortunately, using a larger channel does not solve the problem, as a large aspect ratio favors the growth of streaks caused by a diffusion-induced instability. Based on these observations, we propose a different design for sediment transport experiments.
Anomalous diffusion and long-range correlations in the score evolution of the game of cricket

NASA Astrophysics Data System (ADS)

Ribeiro, Haroldo V.; Mukherjee, Satyam; Zeng, Xiao Han T.

2012-08-01

We investigate the time evolution of the scores of the second most popular sport in the world: the game of cricket. By analyzing, event by event, the scores of more than 2000 matches, we point out that the score dynamics is an anomalous diffusive process. Our analysis reveals that the variance of the process is described by a power-law dependence with a superdiffusive exponent, that the scores are statistically self-similar following a universal Gaussian distribution, and that there are long-range correlations in the score evolution. We employ a generalized Langevin equation with a power-law correlated noise that describes all the empirical findings very well. These observations suggest that competition among agents may be a mechanism leading to anomalous diffusion and long-range correlation.
Atmospheric scattering corrections to solar radiometry

NASA Technical Reports Server (NTRS)

Box, M. A.; Deepak, A.

1979-01-01

Whenever a solar radiometer is used to measure direct solar radiation, some diffuse sky radiation invariably enters the detector's field of view along with the direct beam. Therefore, the atmospheric optical depth obtained by the use of Bouguer's transmission law (also called Beer-Lambert's law), that is valid only for direct radiation, needs to be corrected by taking account of the scattered radiation. This paper discusses the correction factors needed to account for the diffuse (i,e., singly and multiply scattered) radiation and the algorithms developed for retrieving aerosol size distribution from such measurements. For a radiometer with a small field of view (half-cone angle of less than 5 deg) and relatively clear skies (optical depths less than 0.4), it is shown that the total diffuse contribution represents approximately 1% of the total intensity.
Diffusion models for innovation: s-curves, networks, power laws, catastrophes, and entropy.

PubMed

Jacobsen, Joseph J; Guastello, Stephen J

2011-04-01

This article considers models for the diffusion of innovation would be most relevant to the dynamics of early 21st century technologies. The article presents an overview of diffusion models and examines the adoption S-curve, network theories, difference models, influence models, geographical models, a cusp catastrophe model, and self-organizing dynamics that emanate from principles of network configuration and principles of heat diffusion. The diffusion dynamics that are relevant to information technologies and energy-efficient technologies are compared. Finally, principles of nonlinear dynamics for innovation diffusion that could be used to rehabilitate the global economic situation are discussed.
Detecting causality in policy diffusion processes.

PubMed

Grabow, Carsten; Macinko, James; Silver, Diana; Porfiri, Maurizio

2016-08-01

A universal question in network science entails learning about the topology of interaction from collective dynamics. Here, we address this question by examining diffusion of laws across US states. We propose two complementary techniques to unravel determinants of this diffusion process: information-theoretic union transfer entropy and event synchronization. In order to systematically investigate their performance on law activity data, we establish a new stochastic model to generate synthetic law activity data based on plausible networks of interactions. Through extensive parametric studies, we demonstrate the ability of these methods to reconstruct networks, varying in size, link density, and degree heterogeneity. Our results suggest that union transfer entropy should be preferred for slowly varying processes, which may be associated with policies attending to specific local problems that occur only rarely or with policies facing high levels of opposition. In contrast, event synchronization is effective for faster enactment rates, which may be related to policies involving Federal mandates or incentives. This study puts forward a data-driven toolbox to explain the determinants of legal activity applicable to political science, across dynamical systems, information theory, and complex networks.
Detecting causality in policy diffusion processes

NASA Astrophysics Data System (ADS)

Grabow, Carsten; Macinko, James; Silver, Diana; Porfiri, Maurizio

2016-08-01

A universal question in network science entails learning about the topology of interaction from collective dynamics. Here, we address this question by examining diffusion of laws across US states. We propose two complementary techniques to unravel determinants of this diffusion process: information-theoretic union transfer entropy and event synchronization. In order to systematically investigate their performance on law activity data, we establish a new stochastic model to generate synthetic law activity data based on plausible networks of interactions. Through extensive parametric studies, we demonstrate the ability of these methods to reconstruct networks, varying in size, link density, and degree heterogeneity. Our results suggest that union transfer entropy should be preferred for slowly varying processes, which may be associated with policies attending to specific local problems that occur only rarely or with policies facing high levels of opposition. In contrast, event synchronization is effective for faster enactment rates, which may be related to policies involving Federal mandates or incentives. This study puts forward a data-driven toolbox to explain the determinants of legal activity applicable to political science, across dynamical systems, information theory, and complex networks.
Symmetrization of conservation laws with entropy for high-temperature hypersonic computations

NASA Technical Reports Server (NTRS)

Chalot, F.; Hughes, T. J. R.; Shakib, F.

1990-01-01

Results of Hughes, France, and Mallet are generalized to conservation law systems taking into account high-temperature effects. Symmetric forms of different equation sets are derived in terms of entropy variables. First, the case of a general divariant gas is studied; it can be specialized to the usual Navier-Stokes equations, as well as to situations where the gas is vibrationally excited, and undergoes equilibrium chemical reactions. The case of gas in thermochemical nonequilibrium is considered next. Transport phenomena, and in particular mass diffusion, are examined in the framework of symmetric advective-diffusive systems.
Second law of thermodynamics in volume diffusion hydrodynamics in multicomponent gas mixtures

NASA Astrophysics Data System (ADS)

Dadzie, S. Kokou

2012-10-01

We presented the thermodynamic structure of a new continuum flow model for multicomponent gas mixtures. The continuum model is based on a volume diffusion concept involving specific species. It is independent of the observer's reference frame and enables a straightforward tracking of a selected species within a mixture composed of a large number of constituents. A method to derive the second law and constitutive equations accompanying the model is presented. Using the configuration of a rotating fluid we illustrated an example of non-classical flow physics predicted by new contributions in the entropy and constitutive equations.
On the motion of viscous fluids in the presence of diffusion

NASA Astrophysics Data System (ADS)

Secchi, Paolo

1988-01-01

The flow of a viscous incompressible two-component fluid with Fick's-law diffusion is investigated analytically. The existence of a unique global solution for small values of the diffusion coefficient (lambda) is proved for two-dimensional flow. The two- and three-dimensional solutions are also shown to converge toward the solutions of the Navier-Stokes equations for inhomogeneous fluids as lambda approaches zero.
Analysis of Bacteriophage Motion Through a Non-Static Medium

NASA Astrophysics Data System (ADS)

Dickey, Samuel A.

In this work, I investigated the motion of bacteriophages (phages) through their mucosal environment. Recently, biologists here at San Diego State University have proposed a model in which phages move sub-diffusively through mucosal fibers in their hunt for bacteria to prey upon. Through a Hoc protein located upon the capsid of the wild type phages, these phages are allowed to bind to mucosal fibers, and extend the amount of time spent in a single location hunting for bacteria. Contrarily, the delta hoc phages are unable to. The ability of the wild type phages to attach itself to mucosal fibers is what enables its subdiffusive behavior. This study investigates the diffusive behavior of these phages in different mucus concentrations. It expands on previous studies in which only short tracks could be observed. In the study at hand, phages are imaged in a highly doped optical fiber with varying concentrations of mucus present in solution. Through rigorous image processing techniques, trajectories of these phages are created with a minimized noise level. We developed code that created position-versus-time files for each phage present in the experimental data. These files were then further analyzed. The sub-diffusive behavior is investigated via mean squared displacement versus time. The diffusive exponent can be obtained from fits to these data. For large enough time intervals, I always obtained an exponent of one for space and time averaged data. This indicates that the diffusion is normal, or sub-diffusive of the CTRW type. CTRW sub-diffusive motion is characterized by waiting times that resemble a power law distribution and have long tails. I investigate these stuck time distributions, however am unable to determine if a power law or exponential fits the data best. Moreover, the distribution gives the same power law exponent for phages moving through water, or mucus, for wild type and delta hoc phages. These exponents would predict super-diffusive instead of sub-diffusive behavior. We conclude that many of these problems result from the small amount of data available to us and the still primitive conditions of the setup at the time the data were collected.

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