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Sample records for excitable cells modulators

  1. Reciprocal Modulation of IK1-INa Extends Excitability in Cardiac Ventricular Cells.

    Science.gov (United States)

    Varghese, Anthony

    2016-01-01

    The inwardly rectifying potassium current (I K1 ) and the fast inward sodium current (I Na ) are reciprocally modulated in mammalian ventricular myocytes. An increase in the expression of channels responsible for one of these two currents results in a corresponding increase in expression of the other. These currents are critical in the propagation of action potentials (AP) during the normal functioning of the heart. This study identifies a physiological role for I K1 -I Na reciprocal modulation in ventricular fiber activation thresholds and conduction. Simulations of action potentials in single cells and propagating APs in cardiac fibers were carried out using an existing model of electrical activity in cardiac ventricular myocytes. The conductances, G K1 , of the inwardly rectifying potassium current, and G Na , of the fast inward sodium current were modified independently and in tandem to simulate reciprocal modulation. In single cells, independent modulation of G K1 alone resulted in changes in activation thresholds that were qualitatively similar to those for reciprocal G K1 -G Na modulation and unlike those due to independent modulation of G Na alone, indicating that G K1 determines the cellular activation threshold. On the other hand, the variations in conduction velocity in cardiac cell fibers were similar for independent G Na modulation and for tandem changes in G K1 -G Na , suggesting that G Na is primarily responsible for setting tissue AP conduction velocity. Conduction velocity dependence on G K1 -G Na is significantly affected by the intercellular gap junction conductance. While the effects on the passive fiber space constant due to changes in both G K1 and the intercellular gap junction conductance, G gj , were in line with linear cable theory predictions, both conductances had surprisingly large effects on fiber activation thresholds. Independent modulation of G K1 rendered cardiac fibers inexcitable at higher levels of G K1 whereas tandem G K1 -G Na

  2. Dendritic excitability modulates dendritic information processing in a purkinje cell model.

    Science.gov (United States)

    Coop, Allan D; Cornelis, Hugo; Santamaria, Fidel

    2010-01-01

    Using an electrophysiological compartmental model of a Purkinje cell we quantified the contribution of individual active dendritic currents to processing of synaptic activity from granule cells. We used mutual information as a measure to quantify the information from the total excitatory input current (I(Glu)) encoded in each dendritic current. In this context, each active current was considered an information channel. Our analyses showed that most of the information was encoded by the calcium (I(CaP)) and calcium activated potassium (I(Kc)) currents. Mutual information between I(Glu) and I(CaP) and I(Kc) was sensitive to different levels of excitatory and inhibitory synaptic activity that, at the same time, resulted in the same firing rate at the soma. Since dendritic excitability could be a mechanism to regulate information processing in neurons we quantified the changes in mutual information between I(Glu) and all Purkinje cell currents as a function of the density of dendritic Ca (g(CaP)) and Kca (g(Kc)) conductances. We extended our analysis to determine the window of temporal integration of I(Glu) by I(CaP) and I(Kc) as a function of channel density and synaptic activity. The window of information integration has a stronger dependence on increasing values of g(Kc) than on g(CaP), but at high levels of synaptic stimulation information integration is reduced to a few milliseconds. Overall, our results show that different dendritic conductances differentially encode synaptic activity and that dendritic excitability and the level of synaptic activity regulate the flow of information in dendrites.

  3. Lindane blocks GABAA-mediated inhibition and modulates pyramidal cell excitability in the rat hippocampal slice.

    Science.gov (United States)

    Joy, R M; Walby, W F; Stark, L G; Albertson, T E

    1995-01-01

    An in vitro paired-pulse orthodromic stimulation technique was used to examine the effects of lindane on excitatory afferent terminals, CA1 pyramidal cells and recurrent collateral evoked inhibition in the rat hippocampal slice. This was done to establish simultaneous effects on a simple neural network and to develop procedures for more detailed analyses of the effects of lindane. Hippocampal slices 400 microns thick were perfused with oxygenated artificial cerebrospinal fluid. Electrodes were placed in the CA1 region to record extracellular population spike (PS) or excitatory postsynaptic potential (EPSP) responses to stimulation of Schaffer collateral/commissural (SC/C) fibers. Gamma-aminobutyric acid (GABA)-mediated recurrent inhibition was measured using a paired-pulse technique. Perfusion with lindane produced both time and dose dependent changes in a number of the responses measured. The most striking effect produced by lindane was the loss of GABAA-mediated recurrent collateral inhibition. This tended to occur rapidly, often before changes in EPSP or PS responses could be detected. With longer exposures to lindane, repetitive discharge of pyramidal cells developed resulting in multiple PSs to single stimuli. Lindane (50 microM) also completely reversed the effects of the injectable anesthetic, propofol, a compound known to potentiate GABAA-mediated inhibition via a direct action on the GABAA receptor-chloride channel complex. An analysis of input/output relationships at varying stimulus intensities showed that lindane increased EPSP and PS response amplitudes at any given stimulus intensity resulting in a leftward shift in the EPSP amplitude/stimulus intensity, PS amplitude/stimulus intensity and PS amplitude/EPSP amplitude relationships. This effect was most noticeable with low intensity stimuli and became progressively less so as stimulus intensities approached those yielding maximal responses. In addition lindane significantly increased paired pulse

  4. Cell-Specific Cholinergic Modulation of Excitability of Layer 5B Principal Neurons in Mouse Auditory Cortex

    Science.gov (United States)

    Joshi, Ankur; Kalappa, Bopanna I.; Anderson, Charles T.

    2016-01-01

    The neuromodulator acetylcholine (ACh) is crucial for several cognitive functions, such as perception, attention, and learning and memory. Whereas, in most cases, the cellular circuits or the specific neurons via which ACh exerts its cognitive effects remain unknown, it is known that auditory cortex (AC) neurons projecting from layer 5B (L5B) to the inferior colliculus, corticocollicular neurons, are required for cholinergic-mediated relearning of sound localization after occlusion of one ear. Therefore, elucidation of the effects of ACh on the excitability of corticocollicular neurons will bridge the cell-specific and cognitive properties of ACh. Because AC L5B contains another class of neurons that project to the contralateral cortex, corticocallosal neurons, to identify the cell-specific mechanisms that enable corticocollicular neurons to participate in sound localization relearning, we investigated the effects of ACh release on both L5B corticocallosal and corticocollicular neurons. Using in vitro electrophysiology and optogenetics in mouse brain slices, we found that ACh generated nicotinic ACh receptor (nAChR)-mediated depolarizing potentials and muscarinic ACh receptor (mAChR)-mediated hyperpolarizing potentials in AC L5B corticocallosal neurons. In corticocollicular neurons, ACh release also generated nAChR-mediated depolarizing potentials. However, in contrast to the mAChR-mediated hyperpolarizing potentials in corticocallosal neurons, ACh generated prolonged mAChR-mediated depolarizing potentials in corticocollicular neurons. These prolonged depolarizing potentials generated persistent firing in corticocollicular neurons, whereas corticocallosal neurons lacking mAChR-mediated depolarizing potentials did not show persistent firing. We propose that ACh-mediated persistent firing in corticocollicular neurons may represent a critical mechanism required for learning-induced plasticity in AC. SIGNIFICANCE STATEMENT Acetylcholine (ACh) is crucial for cognitive

  5. Corticospinal excitability modulation during action observation.

    Science.gov (United States)

    Sartori, Luisa; Betti, Sonia; Castiello, Umberto

    2013-12-31

    This study used the transcranial magnetic stimulation/motor evoked potential (TMS/MEP) technique to pinpoint when the automatic tendency to mirror someone else's action becomes anticipatory simulation of a complementary act. TMS was delivered to the left primary motor cortex corresponding to the hand to induce the highest level of MEP activity from the abductor digiti minimi (ADM; the muscle serving little finger abduction) as well as the first dorsal interosseus (FDI; the muscle serving index finger flexion/extension) muscles. A neuronavigation system was used to maintain the position of the TMS coil, and electromyographic (EMG) activity was recorded from the right ADM and FDI muscles. Producing original data with regard to motor resonance, the combined TMS/MEP technique has taken research on the perception-action coupling mechanism a step further. Specifically, it has answered the questions of how and when observing another person's actions produces motor facilitation in an onlooker's corresponding muscles and in what way corticospinal excitability is modulated in social contexts.

  6. Evolution of Excited Convective Cells in Plasmas

    DEFF Research Database (Denmark)

    Pécseli, Hans; Juul Rasmussen, Jens; Sugai, H.

    1984-01-01

    Convective cells are excited externally in a fully ionized magnetized plasma and their space-time evolution is investigated by two-dimensional potential measurements. A positive cell is excited externally by control of the end losses in the 'scrape off' layer of a plasma column produced by surface...

  7. The triplet excited state of Bodipy: formation, modulation and application.

    Science.gov (United States)

    Zhao, Jianzhang; Xu, Kejing; Yang, Wenbo; Wang, Zhijia; Zhong, Fangfang

    2015-12-21

    Boron dipyrromethene (Bodipy) is one of the most extensively investigated organic chromophores. Most of the investigations are focused on the singlet excited state of Bodipy, such as fluorescence. In stark contrast, the study of the triplet excited state of Bodipy is limited, but it is an emerging area, since the triplet state of Bodipy is tremendously important for several areas, such as the fundamental photochemistry study, photodynamic therapy (PDT), photocatalysis and triplet-triplet annihilation (TTA) upconversion. The recent developments in the study of the production, modulation and application of the triplet excited state of Bodipy are discussed in this review article. The formation of the triplet state of Bodipy upon photoexcitation, via the well known approach such as the heavy atom effect (including I, Br, Ru, Ir, etc.), and the new methods, such as using a spin converter (e.g. C60), charge recombination, exciton coupling and the doubly substituted excited state, are summarized. All the Bodipy-based triplet photosensitizers show strong absorption of visible or near IR light and the long-lived triplet excited state, which are important for the application of the triplet excited state in PDT or photocatalysis. Moreover, the methods for switching (or modulation) of the triplet excited state of Bodipy were discussed, such as those based on the photo-induced electron transfer (PET), by controlling the competing Förster-resonance-energy-transfer (FRET), or the intermolecular charge transfer (ICT). Controlling the triplet excited state will give functional molecules such as activatable PDT reagents or molecular devices. It is worth noting that switching of the singlet excited state and the triplet state of Bodipy may follow different principles. Application of the triplet excited state of Bodipy in PDT, hydrogen (H2) production, photoredox catalytic organic reactions and TTA upconversion were discussed. The challenges and the opportunities in these areas were

  8. TDCS modulates cortical excitability in patients with disorders of consciousness

    Directory of Open Access Journals (Sweden)

    Yang Bai

    2017-01-01

    Full Text Available Transcranial direct current stimulation (tDCS has been reported to be a promising technique for consciousness improvement for patients with disorders of consciousness (DOC. However, there has been no direct electrophysiological evidence to demonstrate the efficacy of tDCS on patients with DOC. Therefore, we aim to measure the cortical excitability changes induced by tDCS in patients with DOC, to find electrophysiological evidence supporting the therapeutic efficacy of tDCS on patients with DOC. In this study, we enrolled sixteen patients with DOC, including nine vegetative state (VS and seven minimally conscious state (MCS (six females and ten males. TMS-EEG was applied to assess cortical excitability changes after twenty minutes of anodal tDCS of the left dorsolateral prefrontal cortex. Global cerebral excitability were calculated to quantify cortical excitability in the temporal domain: four time intervals (0–100, 100–200, 200–300, 300-400 ms. Then local cerebral excitability in the significantly altered time windows were investigated (frontal, left/right hemispheres, central, and posterior. Compared to baseline and sham stimulation, we found that global cerebral excitability increased in early time windows (0–100 and 100-200 ms for patients with MCS; for the patients with VS, global cerebral excitability increased in the 0-100 ms interval but decreased in the 300-400 ms interval. The local cerebral excitability was significantly different between MCS and VS. The results indicated that tDCS can effectively modulate the cortical excitability of patients with DOC; and the changes in excitability in temporal and spatial domains are different between patients with MCS and those with VS.

  9. Passive listening to preferred motor tempo modulates corticospinal excitability.

    Science.gov (United States)

    Michaelis, Kelly; Wiener, Martin; Thompson, James C

    2014-01-01

    Rhythms are an essential characteristic of our lives, and auditory-motor coupling affects a variety of behaviors. Previous research has shown that the neural regions associated with motor system processing are coupled to perceptual rhythmic and melodic processing such that the perception of rhythmic stimuli can entrain motor system responses. However, the degree to which individual preference modulates the motor system is unknown. Recent work has shown that passively listening to metrically strong rhythms increases corticospinal excitability, as indicated by transcranial magnetic stimulation (TMS). Furthermore, this effect is modulated by high-groove music, or music that inspires movement, while neuroimaging evidence suggests that premotor activity increases with tempos occurring within a preferred tempo (PT) category. PT refers to the rate of a hypothetical endogenous oscillator that may be indicated by spontaneous motor tempo (SMT) and preferred perceptual tempo (PPT) measurements. The present study investigated whether listening to a rhythm at an individual's PT preferentially modulates motor system excitability. SMT was obtained in human participants through a tapping task in which subjects were asked to tap a response key at their most comfortable rate. Subjects listened a 10-beat tone sequence at 11 log-spaced tempos and rated their preference for each (PPT). We found that SMT and PPT measurements were correlated, indicating that preferred and produced tempos occurred at a similar rate. Crucially, single-pulse TMS delivered to left M1 during PPT judgments revealed that corticospinal excitability, measured by motor-evoked potentials (MEPs), was modulated by tempos traveling closer to individual PT. However, the specific nature of this modulation differed across individuals, with some exhibiting an increase in excitability around PT and others exhibiting a decrease. These findings suggest that auditory-motor coupling induced by rhythms is preferentially

  10. Spiral-wave dynamics in excitable medium with excitability modulated by rectangle wave

    International Nuclear Information System (INIS)

    Yuan Guo-Yong

    2011-01-01

    We numerically study the dynamics of spiral waves in the excitable system with the excitability modulated by a rectangle wave. The tip trajectories and their variations with the modulation period T are explained by the corresponding spectrum analysis. For a large T, the external modulation leads to the occurrence of more frequency peaks and these frequencies change with the modulation period according to their specific rules, respectively. Some of the frequencies and a primary frequency f 1 determine the corresponding curvature periods, which are locked into rational multiplies of the modulation period. These frequency-locking behaviours and the limited life-span of the frequencies in their variations with the modulation period constitute many resonant entrainment bands in the T axis. In the main bands, which follow the relation T/T 12 = m/n, the size variable R x of the tip trajectory is a monotonic increasing function of T. The rest of the frequencies are linear combinations of the two ones. Due to the complex dynamics, many unique tip trajectories appear at some certain T. We find also that spiral waves are eliminated when T is chosen from the end of the main resonant bands. This offers a useful method of controling the spiral wave. (general)

  11. Chemical modulation of electronic structure at the excited state

    Science.gov (United States)

    Li, F.; Song, C.; Gu, Y. D.; Saleem, M. S.; Pan, F.

    2017-12-01

    Spin-polarized electronic structures are the cornerstone of spintronics, and have thus attracted a significant amount of interest; in particular, researchers are looking into how to modulate the electronic structure to enable multifunctional spintronics applications, especially in half-metallic systems. However, the control of the spin polarization has only been predicted in limited two-dimensional systems with spin-polarized Dirac structures and is difficult to achieve experimentally. Here, we report the modulation of the electronic structure in the light-induced excited state in a typical half-metal, L a1 /2S r1 /2Mn O3 -δ . According to the spin-transport measurements, there appears a light-induced increase in magnetoresistance due to the enhanced spin scattering, which is closely associated with the excited spin polarization. Strikingly, the light-induced variation can be enhanced via alcohol processing and reduced by oxygen annealing. X-ray photoelectron spectroscopy measurements show that in the chemical process, a redox reaction occurs with a change in the valence of Mn. Furthermore, first-principles calculations reveal that the change in the valence of Mn alters the electronic structure and consequently modulates the spin polarization in the excited state. Our findings thus report a chemically tunable electronic structure, demonstrating interesting physics and the potential for multifunctional applications and ultrafast spintronics.

  12. Effects of excitation intensity on the photocurrent response of thin film silicon solar modules

    Science.gov (United States)

    Kim, Q.; Shumka, A.; Trask, J.

    1986-01-01

    Photocurrent responses of amorphous thin film silicon solar modules at room temperature were studied at different excitation intensities using various monochromatic light sources. Photocurrent imaging techniques have been effectively used to locate rapidly, and non-destructively, failure and defect sites in the multilayer thin film device. Differences observed in the photocurrent response characteristics for two different cells in the same amorphous thin film silicon solar module suggest the possibility of the formation of dissimilarly active devices, even though the module is processed in the same fabrication process. Possible mechanisms are discussed.

  13. Magnetic excitations in modulated PrNi2Si2

    International Nuclear Information System (INIS)

    Blanco, J.A.; Nicklow, R.M.; Schmitt, D.

    1994-01-01

    The magnetic excitations in a single crystal of PrNi 2 Si 2 have been studied by inelastic neutron scattering. Dispersion curves have been followed through the centered tetragonal Brillouin zone. In the paramagnetic phase, at 39 K, the lowest energy magnetic branch exhibits an important dispersion ranging from 1.9 to 3.5 meV, the minimum energy occuring at the wave vector of the ordered phase; from the observed dispersion the inter-ionic isotropic bilinear exchange parameters are deduced. At 4.2 K, in the modulated phase, the same branch presents a dispersion slightly larger, but not significantly different

  14. Lithium. Effects on excitable cell membranes

    NARCIS (Netherlands)

    Ploeger, Egbert Johan

    1974-01-01

    LITHIUM: Effects on excitable cell membranes. Lithium salts have been used in the treatment of manic-depressive psychosis for many years but their mechanism of action is not well understood. Many workers assume that the action of lithium on catecholamine metabolism and/or on electrolyte distribution

  15. Hilar mossy cell circuitry controlling dentate granule cell excitability

    Directory of Open Access Journals (Sweden)

    Seiichiro eJinde

    2013-02-01

    Full Text Available Glutamatergic hilar mossy cells of the dentate gyrus can either excite or inhibit distant granule cells, depending on whether their direct excitatory projections to granule cells or their projections to local inhibitory interneurons dominate. However, it remains controversial whether the net effect of mossy cell loss is granule cell excitation or inhibition. Clarifying this controversy has particular relevance to temporal lobe epilepsy, which is marked by dentate granule cell hyperexcitability and extensive loss of dentate hilar mossy cells. Two diametrically opposed hypotheses have been advanced to explain this granule cell hyperexcitability – the dormant basket cell and the irritable mossy cell hypotheses. The dormant basket cell hypothesis proposes that mossy cells normally exert a net inhibitory effect on granule cells and therefore their loss causes dentate granule cell hyperexcitability. The irritable mossy cell hypothesis takes the opposite view that mossy cells normally excite granule cells and that the surviving mossy cells in epilepsy increase their activity, causing granule cell excitation. The inability to eliminate mossy cells selectively has made it difficult to test these two opposing hypotheses. To this end, we developed a transgenic toxin-mediated, mossy cell-ablation mouse line. Using these mutants, we demonstrated that the extensive elimination of hilar mossy cells causes granule cell hyperexcitability, although the mossy cell loss observed appeared insufficient to cause clinical epilepsy. In this review, we focus on this topic and also suggest that different interneuron populations may mediate mossy cell-induced translamellar lateral inhibition and intralamellar recurrent inhibition. These unique local circuits in the dentate hilar region may be centrally involved in the functional organization of the dentate gyrus.

  16. HCN Channels—Modulators of Cardiac and Neuronal Excitability

    Directory of Open Access Journals (Sweden)

    Stefan Herrmann

    2015-01-01

    Full Text Available Hyperpolarization-activated cyclic nucleotide-gated (HCN channels comprise a family of cation channels activated by hyperpolarized membrane potentials and stimulated by intracellular cyclic nucleotides. The four members of this family, HCN1–4, show distinct biophysical properties which are most evident in the kinetics of activation and deactivation, the sensitivity towards cyclic nucleotides and the modulation by tyrosine phosphorylation. The four isoforms are differentially expressed in various excitable tissues. This review will mainly focus on recent insights into the functional role of the channels apart from their classic role as pacemakers. The importance of HCN channels in the cardiac ventricle and ventricular hypertrophy will be discussed. In addition, their functional significance in the peripheral nervous system and nociception will be examined. The data, which are mainly derived from studies using transgenic mice, suggest that HCN channels contribute significantly to cellular excitability in these tissues. Remarkably, the impact of the channels is clearly more pronounced in pathophysiological states including ventricular hypertrophy as well as neural inflammation and neuropathy suggesting that HCN channels may constitute promising drug targets in the treatment of these conditions. This perspective as well as the current therapeutic use of HCN blockers will also be addressed.

  17. Developing Sensitive and Selective Nanosensors: A Single Molecule - Multiple Excitation Source Approach. Altairnano Lithium Ion Nano-scaled Titanate Oxide Cell and Module Abuse Testing

    Science.gov (United States)

    2012-03-13

    Acids: Hydrochloric Acid, Nitric Acid, Sulfuric Acid, Acetic Acid. Bases: Ammonia , Household Bleach. Organics: Toluene, Acetone, Ethanol, Methanol...within a test cell equipped with a scrubber system and audio/video feeds. Twelve internal and four external thermocouples were connected to the data

  18. Inhibition of light tunneling for multichannel excitations in longitudinally modulated waveguide arrays

    International Nuclear Information System (INIS)

    Lobanov, Valery E.; Vysloukh, Victor A.; Kartashov, Yaroslav V.

    2010-01-01

    We consider the evolution of multichannel excitations in longitudinally modulated waveguide arrays where the refractive index either oscillates out-of-phase in all neighboring waveguides or when it is modulated in phase in several central waveguides surrounded by out-of-phase oscillating neighbors. Both types of modulations allow resonant inhibition of light tunneling, but only the modulation of the latter type conserves the internal structure of multichannel excitations. We show that parameter regions where light tunneling inhibition is possible depend on the symmetry and structure of multichannel excitations. Antisymmetric multichannel excitations are more robust than their symmetric counterparts and experience nonlinearity-induced delocalization at higher amplitudes.

  19. Cdk5 modulates cocaine reward, motivation, and striatal neuron excitability.

    Science.gov (United States)

    Benavides, David R; Quinn, Jennifer J; Zhong, Ping; Hawasli, Ammar H; DiLeone, Ralph J; Kansy, Janice W; Olausson, Peter; Yan, Zhen; Taylor, Jane R; Bibb, James A

    2007-11-21

    Cyclin-dependent kinase 5 (Cdk5) regulates dopamine neurotransmission and has been suggested to serve as a homeostatic target of chronic psychostimulant exposure. To study the role of Cdk5 in the modulation of the cellular and behavioral effects of psychoactive drugs of abuse, we developed Cre/loxP conditional knock-out systems that allow temporal and spatial control of Cdk5 expression in the adult brain. Here, we report the generation of Cdk5 conditional knock-out (cKO) mice using the alphaCaMKII promoter-driven Cre transgenic line (CaMKII-Cre). In this model system, loss of Cdk5 in the adult forebrain increased the psychomotor-activating effects of cocaine. Additionally, these CaMKII-Cre Cdk5 cKO mice show enhanced incentive motivation for food as assessed by instrumental responding on a progressive ratio schedule of reinforcement. Behavioral changes were accompanied by increased excitability of medium spiny neurons in the nucleus accumbens (NAc) in Cdk5 cKO mice. To study NAc-specific effects of Cdk5, another model system was used in which recombinant adeno-associated viruses expressing Cre recombinase caused restricted loss of Cdk5 in NAc neurons. Targeted knock-out of Cdk5 in the NAc facilitated cocaine-induced locomotor sensitization and conditioned place preference for cocaine. These results suggest that Cdk5 acts as a negative regulator of neuronal excitability in the NAc and that Cdk5 may govern the behavioral effects of cocaine and motivation for reinforcement.

  20. Changes in Appetitive Associative Strength Modulates Nucleus Accumbens, But Not Orbitofrontal Cortex Neuronal Ensemble Excitability.

    Science.gov (United States)

    Ziminski, Joseph J; Hessler, Sabine; Margetts-Smith, Gabriella; Sieburg, Meike C; Crombag, Hans S; Koya, Eisuke

    2017-03-22

    Cues that predict the availability of food rewards influence motivational states and elicit food-seeking behaviors. If a cue no longer predicts food availability, then animals may adapt accordingly by inhibiting food-seeking responses. Sparsely activated sets of neurons, coined "neuronal ensembles," have been shown to encode the strength of reward-cue associations. Although alterations in intrinsic excitability have been shown to underlie many learning and memory processes, little is known about these properties specifically on cue-activated neuronal ensembles. We examined the activation patterns of cue-activated orbitofrontal cortex (OFC) and nucleus accumbens (NAc) shell ensembles using wild-type and Fos-GFP mice, which express green fluorescent protein (GFP) in activated neurons, after appetitive conditioning with sucrose and extinction learning. We also investigated the neuronal excitability of recently activated, GFP+ neurons in these brain areas using whole-cell electrophysiology in brain slices. Exposure to a sucrose cue elicited activation of neurons in both the NAc shell and OFC. In the NAc shell, but not the OFC, these activated GFP+ neurons were more excitable than surrounding GFP- neurons. After extinction, the number of neurons activated in both areas was reduced and activated ensembles in neither area exhibited altered excitability. These data suggest that learning-induced alterations in the intrinsic excitability of neuronal ensembles is regulated dynamically across different brain areas. Furthermore, we show that changes in associative strength modulate the excitability profile of activated ensembles in the NAc shell. SIGNIFICANCE STATEMENT Sparsely distributed sets of neurons called "neuronal ensembles" encode learned associations about food and cues predictive of its availability. Widespread changes in neuronal excitability have been observed in limbic brain areas after associative learning, but little is known about the excitability changes that

  1. D2O-induced cell excitation

    International Nuclear Information System (INIS)

    Andjus, P.R.; Vucelic, D.

    1990-01-01

    The effects of deuterium oxide (D 2 O) on giant internodal cells of the fresh water alga Chara gymnophylla, were investigated. D 2 O causes membrane excitation followed by potassium leakage. The primary effect consists of an almost instantaneous membrane depolarization resembling an action potential with incomplete repolarization. A hypothesis was proposed which deals with an osmotic stress effect of D 2 O on membrane ion channels followed by the suppression of the electrogenic pump activity. The initial changes (potential spike and rapid K+ efflux) may represent the previously undetected link between the D 2 O-induced temporary arrest of protoplasmic streaming and the early events triggered at the plasma membrane level as the primary site of D 2 O action

  2. Hearing loss alters serotonergic modulation of intrinsic excitability in auditory cortex.

    Science.gov (United States)

    Rao, Deepti; Basura, Gregory J; Roche, Joseph; Daniels, Scott; Mancilla, Jaime G; Manis, Paul B

    2010-11-01

    early sensorineural hearing loss affects the ability of 5-HT receptor activation to modulate A1 pyramidal cell excitability.

  3. Transparent solar cell window module

    Energy Technology Data Exchange (ETDEWEB)

    Chau, Joseph Lik Hang; Chen, Ruei-Tang; Hwang, Gan-Lin; Tsai, Ping-Yuan [Nanopowder and Thin Film Technology Center, ITRI South, Industrial Technology Research Institute, Tainan County 709 (China); Lin, Chien-Chu [I-Lai Acrylic Corporation, Tainan City (China)

    2010-03-15

    A transparent solar cell window module based on the integration of traditional silicon solar cells and organic-inorganic nanocomposite material was designed and fabricated. The transparent solar cell window module was composed of a nanocomposite light-guide plate and traditional silicon solar cells. The preparation of the nanocomposite light-guide plate is easy without modification of the traditional casting process, the nanoparticles sol can be added directly to the polymethyl methacrylate (PMMA) monomer syrup during the process. The solar energy collected by this window can be used to power up small household electrical appliances. (author)

  4. Photovoltaic cell module and method of forming

    Science.gov (United States)

    Howell, Malinda; Juen, Donnie; Ketola, Barry; Tomalia, Mary Kay

    2017-12-12

    A photovoltaic cell module, a photovoltaic array including at least two modules, and a method of forming the module are provided. The module includes a first outermost layer and a photovoltaic cell disposed on the first outermost layer. The module also includes a second outermost layer disposed on the photovoltaic cell and sandwiching the photovoltaic cell between the second outermost layer and the first outermost layer. The method of forming the module includes the steps of disposing the photovoltaic cell on the first outermost layer, disposing a silicone composition on the photovoltaic cell, and compressing the first outermost layer, the photovoltaic cell, and the second layer to form the photovoltaic cell module.

  5. Digital photocontrol of the network of live excitable cells

    Science.gov (United States)

    Erofeev, I. S.; Magome, N.; Agladze, K. I.

    2011-11-01

    Recent development of tissue engineering techniques allows creating and maintaining almost indefinitely networks of excitable cells with desired architecture. We coupled the network of live excitable cardiac cells with a common computer by sensitizing them to light, projecting a light pattern on the layer of cells, and monitoring excitation with the aid of fluorescent probes (optical mapping). As a sensitizing substance we used azobenzene trimethylammonium bromide (AzoTAB). This substance undergoes cis-trans-photoisomerization and trans-isomer of AzoTAB inhibits excitation in the cardiac cells, while cis-isomer does not. AzoTAB-mediated sensitization allows, thus, reversible and dynamic control of the excitation waves through the entire cardiomyocyte network either uniformly, or in a preferred spatial pattern. Technically, it was achieved by coupling a common digital projector with a macroview microscope and using computer graphic software for creating the projected pattern of conducting pathways. This approach allows real time interactive photocontrol of the heart tissue.

  6. Modulation of motor excitability by metricality of tone sequences

    DEFF Research Database (Denmark)

    Cameron, David; Stewart, Lauren; Pearce, Marcus

    2012-01-01

    amplitude. These results demonstrate that the pure metrical structure of an auditory rhythm presented as generic parametrically varied tone sequences can influence motor excitability but that the picture may be more complex for real recordings of musical pieces. (PsycINFO Database Record (c) 2013 APA, all...

  7. Wideband excitation in nonlinear vibro-acoustic modulation for damage detection

    Science.gov (United States)

    Klepka, A.; Adamczyk, M.; Pieczonka, L.; Staszewski, W. J.

    2016-04-01

    The paper discusses the use of wideband excitation in nonlinear vibro-acoustic modulation technique (VAM) used for damage detection. In its original form, two mono-harmonic signals (low and high frequency) are used for excitation. The low frequency excitation is typically selected based on a modal analysis test and high frequency excitation is selected arbitrarily in the ultrasonic frequency range. This paper presents a different approach with use of wideband excitation signals. The proposed approach gives the possibility to simplify the testing procedure by omitting the modal test used to determine the value of low frequency excitation. Simultaneous use of wideband excitation for high frequency solves the ambiguity related to the selection of the frequency of acoustic wave. Broadband excitation signals require, however, more elaborate signal processing methods to determine the intensity of modulation for a given bandwidth. The paper discusses the proposed approach and the related signal processing procedure. Experimental validation of the proposed technique is performed on a laminated composite plate with a barely visible impact damage that was generated in an impact test. Piezoceramic actuators are used for vibration excitation and a scanning laser vibrometer is used for noncontact data acquisition.

  8. Viewing instructions accompanying action observation modulate corticospinal excitability

    Directory of Open Access Journals (Sweden)

    David James Wright

    2016-02-01

    Full Text Available Action observation interventions may have the potential to contribute to improved motor function in motor (relearning settings by promoting functional activity and plasticity in the motor regions of the brain. Optimal methods for delivering such interventions, however, have yet to be established. This experiment investigated the effect on corticospinal excitability of manipulating the viewing instructions provided to participants (N = 21 prior to action observation. Specifically, motor evoked potential responses measured from the right hand muscles following single-pulse transcranial magnetic stimulation to the left motor cortex were compared when participants were instructed to observe finger-thumb opposition movement sequences: (i passively; (ii with the intent to imitate the observed movement; or (iii whilst simultaneously and actively imagining that they were performing the movement as they observed it. All three action observation viewing instructions facilitated corticospinal excitability to a greater extent than did observation of a static hand. In addition, the extent to which corticospinal excitability was facilitated was greater during combined observation and imagery, compared to passive observation. These findings have important implications for the design of action observation interventions in motor (relearning settings, where instructions that encourage observers to simultaneously imagine themselves performing the observed movement may offer the current optimal method for improving motor function through action observation.

  9. Adrenergic Modulation Regulates the Dendritic Excitability of Layer 5 Pyramidal Neurons In Vivo

    Directory of Open Access Journals (Sweden)

    Christina Labarrera

    2018-04-01

    Full Text Available Summary: The excitability of the apical tuft of layer 5 pyramidal neurons is thought to play a crucial role in behavioral performance and synaptic plasticity. We show that the excitability of the apical tuft is sensitive to adrenergic neuromodulation. Using two-photon dendritic Ca2+ imaging and in vivo whole-cell and extracellular recordings in awake mice, we show that application of the α2A-adrenoceptor agonist guanfacine increases the probability of dendritic Ca2+ events in the tuft and lowers the threshold for dendritic Ca2+ spikes. We further show that these effects are likely to be mediated by the dendritic current Ih. Modulation of Ih in a realistic compartmental model controlled both the generation and magnitude of dendritic calcium spikes in the apical tuft. These findings suggest that adrenergic neuromodulation may affect cognitive processes such as sensory integration, attention, and working memory by regulating the sensitivity of layer 5 pyramidal neurons to top-down inputs. : Labarrera et al. show that noradrenergic neuromodulation can be an effective way to regulate the interaction between different input streams of information processed by an individual neuron. These findings may have important implications for our understanding of how adrenergic neuromodulation affects sensory integration, attention, and working memory. Keywords: cortical layer 5 pyramidal neuron, dendrites, norepinephrine, HCN, Ih, Ca2+ spike, apical tuft, guanfacine, ADHD, somatosensory cortex

  10. Brain Distribution and Modulation of Neuronal Excitability by Indicaxanthin From Opuntia Ficus Indica Administered at Nutritionally-Relevant Amounts

    Directory of Open Access Journals (Sweden)

    Giuditta Gambino

    2018-05-01

    Full Text Available Several studies have recently investigated the role of nutraceuticals in complex pathophysiological processes such as oxidative damages, inflammatory conditions and excitotoxicity. In this regard, the effects of nutraceuticals on basic functions of neuronal cells, such as excitability, are still poorly investigated. For this reason, the possible modulation of neuronal excitability by phytochemicals (PhC could represent an interesting field of research given that excitotoxicity phenomena are involved in neurodegenerative alterations leading, for example, to Alzheimer’s disease. The present study was focused on indicaxanthin from Opuntia ficus indica, a bioactive betalain pigment, with a proven antioxidant and anti-inflammatory potential, previously found to cross blood-brain barrier (BBB and to modulate the bioelectric activity of hippocampal neurons. On this basis, we aimed at detecting the specific brain areas where indicaxanthin localizes after oral administration at dietary-achievable amounts and highlighting eventual local effects on the excitability of single neuronal units. HPLC analysis of brain tissue 1 h after ingestion of 2 μmol/kg indicaxanthin indicated that the phytochemical accumulates in cortex, hippocampus, diencephalon, brainstem and cerebellum, but not in the striato-pallidal complex. Then, electrophysiological recordings, applying the microiontophoretic technique, were carried out with different amounts of indicaxanthin (0.34, 0.17, 0.085 ng/neuron to assess whether indicaxanthin influenced the neuronal firing rate. The data showed that the bioelectric activity of neurons belonging to different brain areas was modulated after local injection of indicaxanthin, mainly with dose-related responses. A predominating inhibitory effect was observed, suggesting a possible novel beneficial effect of indicaxanthin in reducing cell excitability. These findings can constitute a new rationale for exploring biological mechanisms through

  11. Brain Distribution and Modulation of Neuronal Excitability by Indicaxanthin From Opuntia Ficus Indica Administered at Nutritionally-Relevant Amounts

    Science.gov (United States)

    Gambino, Giuditta; Allegra, Mario; Sardo, Pierangelo; Attanzio, Alessandro; Tesoriere, Luisa; Livrea, Maria A.; Ferraro, Giuseppe; Carletti, Fabio

    2018-01-01

    Several studies have recently investigated the role of nutraceuticals in complex pathophysiological processes such as oxidative damages, inflammatory conditions and excitotoxicity. In this regard, the effects of nutraceuticals on basic functions of neuronal cells, such as excitability, are still poorly investigated. For this reason, the possible modulation of neuronal excitability by phytochemicals (PhC) could represent an interesting field of research given that excitotoxicity phenomena are involved in neurodegenerative alterations leading, for example, to Alzheimer’s disease. The present study was focused on indicaxanthin from Opuntia ficus indica, a bioactive betalain pigment, with a proven antioxidant and anti-inflammatory potential, previously found to cross blood-brain barrier (BBB) and to modulate the bioelectric activity of hippocampal neurons. On this basis, we aimed at detecting the specific brain areas where indicaxanthin localizes after oral administration at dietary-achievable amounts and highlighting eventual local effects on the excitability of single neuronal units. HPLC analysis of brain tissue 1 h after ingestion of 2 μmol/kg indicaxanthin indicated that the phytochemical accumulates in cortex, hippocampus, diencephalon, brainstem and cerebellum, but not in the striato-pallidal complex. Then, electrophysiological recordings, applying the microiontophoretic technique, were carried out with different amounts of indicaxanthin (0.34, 0.17, 0.085 ng/neuron) to assess whether indicaxanthin influenced the neuronal firing rate. The data showed that the bioelectric activity of neurons belonging to different brain areas was modulated after local injection of indicaxanthin, mainly with dose-related responses. A predominating inhibitory effect was observed, suggesting a possible novel beneficial effect of indicaxanthin in reducing cell excitability. These findings can constitute a new rationale for exploring biological mechanisms through which PhC could

  12. Compact 3D printed module for fluorescence and label-free imaging using evanescent excitation

    Science.gov (United States)

    Pandey, Vikas; Gupta, Shalini; Elangovan, Ravikrishnan

    2018-01-01

    Total internal reflection fluorescence (TIRF) microscopy is widely used for selective excitation and high-resolution imaging of fluorophores, and more recently label-free nanosized objects, with high vertical confinement near a liquid-solid interface. Traditionally, high numerical aperture objectives (>1.4) are used to simultaneously generate evanescent waves and collect fluorescence emission signals which limits their use to small area imaging (filters to prevent specular reflection within the objective lenses. We have developed a compact 3D module called cTIRF that can generate evanescent waves in microscope glass slides via a planar waveguide illumination. The module can be attached as a fixture to any existing optical microscope, converting it into a TIRF and enabling high signal-to-noise ratio (SNR) fluorescence imaging using any magnification objective. As the incidence optics is perpendicular to the detector, label-free evanescent scattering-based imaging of submicron objects can also be performed without using emission filters. SNR is significantly enhanced in this case as compared to cTIRF alone, as seen through our model experiments performed on latex beads and mammalian cells. Extreme flexibility and the low cost of our approach makes it scalable for limited resource settings.

  13. Electrical field excitation in non-uniform plasma by a modulated electron beam

    International Nuclear Information System (INIS)

    Anisimov, I.O.; Borisov, O.A.

    2000-01-01

    Excitation of electric fields due to a modulated electron beam in a warm non-uniform plasma is treated for weak beams in warm plasma. It is shown that the maximum electric field magnitude that is reached near the local plasma resonance point depends significantly on the direction of the electron stream motion. In collisional plasma the magnitude of the Langmuir wave that propagates to the subcritical plasma also depends on the direction of the electron stream motion. The motion of the modulated electron stream front results in beatings between oscillations on the modulation frequency and on the local electron plasma frequencies at the initial moment. Later these beatings damp in the supercritical plasma, whereas in the subcritical plasma they are transformed into spatial beatings between the field of the modulated electron stream and the excited Langmuir wave. (orig.)

  14. Self-modulated dynamics of a relativistic charged particle beam in plasma wake field excitation

    Energy Technology Data Exchange (ETDEWEB)

    Akhter, T.; Fedele, R. [Dipartimento di Fisica ‘Ettore Pancini’, Università di Napoli Federico II and INFN Sezione di Napoli, Napoli (Italy); Nicola, S. De [CNR-SPIN and INFN Sezione di Napoli, Napoli (Italy); Tanjia, F. [Dipartimento di Fisica ‘Ettore Pancini’, Università di Napoli Federico II and INFN Sezione di Napoli, Napoli (Italy); Jovanović, D. [Institute of Physics, University of Belgrade, Belgrade (Serbia); Mannan, A. [Department of Physics, Jahangirnagar University, Savar, Dhaka (Bangladesh)

    2016-09-01

    The self-modulated dynamics of a relativistic charged particle beam is provided within the context of the theory of plasma wake field excitation. The self-consistent description of the beam dynamics is provided by coupling the Vlasov equation with a Poisson-type equation relating the plasma wake potential to the beam density. An analysis of the beam envelope self-modulation is then carried out and the criteria for the occurrence of the instability are discussed thereby.

  15. Modulation of Human Corticospinal Excitability by Paired Associative Stimulation

    Directory of Open Access Journals (Sweden)

    Richard G. Carson

    2013-12-01

    Full Text Available Paired Associative Stimulation (PAS has come to prominence as a potential therapeutic intervention for the treatment of brain injury/disease, and as an experimental method with which to investigate Hebbian principles of neural plasticity in humans. Prototypically, a single electrical stimulus is directed to a peripheral nerve in advance of transcranial magnetic stimulation (TMS delivered to the contralateral primary motor cortex (M1. Repeated pairing of the stimuli (i.e. association over an extended period may increase or decrease the excitability of corticospinal projections from M1, in manner that depends on the interstimulus interval (ISI. It has been suggested that these effects represent a form of associative long-term potentiation (LTP and depression (LTD that bears resemblance to spike-timing dependent plasticity (STDP as it has been elaborated in animal models. With a large body of empirical evidence having emerged since the cardinal features of PAS were first described, and in light of the variations from the original protocols that have been implemented, it is opportune to consider whether the phenomenology of PAS remains consistent with the characteristic features that were initially disclosed. This assessment necessarily has bearing upon interpretation of the effects of PAS in relation to the specific cellular pathways that are putatively engaged, including those that adhere to the rules of STDP. The balance of evidence suggests that the mechanisms that contribute to the LTP- and LTD-type responses to PAS differ depending on the precise nature of the induction protocol that is used. In addition to emphasising the requirement for additional explanatory models, in the present analysis we highlight the key features of the PAS phenomenology that require interpretation.

  16. Memory Deficits Are Associated with Impaired Ability to Modulate Neuronal Excitability in Middle-Aged Mice

    Science.gov (United States)

    Kaczorowski, Catherine C.; Disterhoft, John F.

    2009-01-01

    Normal aging disrupts hippocampal neuroplasticity and learning and memory. Aging deficits were exposed in a subset (30%) of middle-aged mice that performed below criterion on a hippocampal-dependent contextual fear conditioning task. Basal neuronal excitability was comparable in middle-aged and young mice, but learning-related modulation of the…

  17. Subfemtosecond pulse generation by cascade-stimulated Raman scattering with modulated Raman excitation

    International Nuclear Information System (INIS)

    Wu Kun; Wu Jian; Zeng Heping

    2003-01-01

    Subfemtosecond (sub-fs) pulses can be generated by cascade-stimulated Raman scattering in a Raman medium with modulated Raman excitations, driven by two sufficiently intense laser beams, one of which is amplitude modulated. The nonadiabatic Raman interaction establishes a strong modulated Raman coherence, which supports compression of the generated broadband Raman sidebands to a train of sub-fs pulses regardless of whether the carrier frequencies of the driving lasers are tuned above, below or on two-photon Raman resonance. (letter to the editor)

  18. Pharmacological modulation of cortical excitability shifts induced by transcranial direct current stimulation in humans.

    Science.gov (United States)

    Nitsche, M A; Fricke, K; Henschke, U; Schlitterlau, A; Liebetanz, D; Lang, N; Henning, S; Tergau, F; Paulus, W

    2003-11-15

    Transcranial direct current stimulation (tDCS) of the human motor cortex results in polarity-specific shifts of cortical excitability during and after stimulation. Anodal tDCS enhances and cathodal stimulation reduces excitability. Animal experiments have demonstrated that the effect of anodal tDCS is caused by neuronal depolarisation, while cathodal tDCS hyperpolarises cortical neurones. However, not much is known about the ion channels and receptors involved in these effects. Thus, the impact of the sodium channel blocker carbamazepine, the calcium channel blocker flunarizine and the NMDA receptor antagonist dextromethorphane on tDCS-elicited motor cortical excitability changes of healthy human subjects were tested. tDCS-protocols inducing excitability alterations (1) only during tDCS and (2) eliciting long-lasting after-effects were applied after drug administration. Carbamazepine selectively eliminated the excitability enhancement induced by anodal stimulation during and after tDCS. Flunarizine resulted in similar changes. Antagonising NMDA receptors did not alter current-generated excitability changes during a short stimulation, which elicits no after-effects, but prevented the induction of long-lasting after-effects independent of their direction. These results suggest that, like in other animals, cortical excitability shifts induced during tDCS in humans also depend on membrane polarisation, thus modulating the conductance of sodium and calcium channels. Moreover, they suggest that the after-effects may be NMDA receptor dependent. Since NMDA receptors are involved in neuroplastic changes, the results suggest a possible application of tDCS in the modulation or induction of these processes in a clinical setting. The selective elimination of tDCS-driven excitability enhancements by carbamazepine proposes a role for this drug in focussing the effects of cathodal tDCS, which may have important future clinical applications.

  19. Snail modulates cell metabolism in MDCK cells

    Energy Technology Data Exchange (ETDEWEB)

    Haraguchi, Misako, E-mail: haraguci@m3.kufm.kagoshima-u.ac.jp [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Indo, Hiroko P. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Iwasaki, Yasumasa [Health Care Center, Kochi University, Kochi 780-8520 (Japan); Iwashita, Yoichiro [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Fukushige, Tomoko [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Majima, Hideyuki J. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Izumo, Kimiko; Horiuchi, Masahisa [Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Kanekura, Takuro [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Furukawa, Tatsuhiko [Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Ozawa, Masayuki [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)

    2013-03-22

    Highlights: ► MDCK/snail cells were more sensitive to glucose deprivation than MDCK/neo cells. ► MDCK/snail cells had decreased oxidative phosphorylation, O{sub 2} consumption and ATP content. ► TCA cycle enzyme activity, but not expression, was lower in MDCK/snail cells. ► MDCK/snail cells showed reduced PDH activity and increased PDK1 expression. ► MDCK/snail cells showed reduced expression of GLS2 and ACLY. -- Abstract: Snail, a repressor of E-cadherin gene transcription, induces epithelial-to-mesenchymal transition and is involved in tumor progression. Snail also mediates resistance to cell death induced by serum depletion. By contrast, we observed that snail-expressing MDCK (MDCK/snail) cells undergo cell death at a higher rate than control (MDCK/neo) cells in low-glucose medium. Therefore, we investigated whether snail expression influences cell metabolism in MDCK cells. Although gylcolysis was not affected in MDCK/snail cells, they did exhibit reduced pyruvate dehydrogenase (PDH) activity, which controls pyruvate entry into the tricarboxylic acid (TCA) cycle. Indeed, the activity of multiple enzymes involved in the TCA cycle was decreased in MDCK/snail cells, including that of mitochondrial NADP{sup +}-dependent isocitrate dehydrogenase (IDH2), succinate dehydrogenase (SDH), and electron transport Complex II and Complex IV. Consequently, lower ATP content, lower oxygen consumption and increased survival under hypoxic conditions was also observed in MDCK/snail cells compared to MDCK/neo cells. In addition, the expression and promoter activity of pyruvate dehydrogenase kinase 1 (PDK1), which phosphorylates and inhibits the activity of PDH, was increased in MDCK/snail cells, while expression levels of glutaminase 2 (GLS2) and ATP-citrate lyase (ACLY), which are involved in glutaminolysis and fatty acid synthesis, were decreased in MDCK/snail cells. These results suggest that snail modulates cell metabolism by altering the expression and activity of

  20. PRRT2 controls neuronal excitability by negatively modulating Na+ channel 1.2/1.6 activity.

    Science.gov (United States)

    Fruscione, Floriana; Valente, Pierluigi; Sterlini, Bruno; Romei, Alessandra; Baldassari, Simona; Fadda, Manuela; Prestigio, Cosimo; Giansante, Giorgia; Sartorelli, Jacopo; Rossi, Pia; Rubio, Alicia; Gambardella, Antonio; Nieus, Thierry; Broccoli, Vania; Fassio, Anna; Baldelli, Pietro; Corradi, Anna; Zara, Federico; Benfenati, Fabio

    2018-04-01

    -dependent Na+ channels in homozygous PRRT2 knockout human and mouse neurons and that, in addition to the reported synaptic functions, PRRT2 is an important negative modulator of Nav1.2 and Nav1.6 channels. Given the predominant paroxysmal character of PRRT2-linked diseases, the disturbance in cellular excitability by lack of negative modulation of Na+ channels appears as the key pathogenetic mechanism.

  1. PRRT2 controls neuronal excitability by negatively modulating Na+ channel 1.2/1.6 activity

    Science.gov (United States)

    Fruscione, Floriana; Valente, Pierluigi; Sterlini, Bruno; Romei, Alessandra; Baldassari, Simona; Fadda, Manuela; Prestigio, Cosimo; Giansante, Giorgia; Sartorelli, Jacopo; Rossi, Pia; Rubio, Alicia; Gambardella, Antonio; Nieus, Thierry; Broccoli, Vania; Fassio, Anna; Baldelli, Pietro; Corradi, Anna; Zara, Federico

    2018-01-01

    voltage-dependent Na+ channels in homozygous PRRT2 knockout human and mouse neurons and that, in addition to the reported synaptic functions, PRRT2 is an important negative modulator of Nav1.2 and Nav1.6 channels. Given the predominant paroxysmal character of PRRT2-linked diseases, the disturbance in cellular excitability by lack of negative modulation of Na+ channels appears as the key pathogenetic mechanism. PMID:29554219

  2. Damage detection and locating using tone burst and continuous excitation modulation method

    Science.gov (United States)

    Li, Zheng; Wang, Zhi; Xiao, Li; Qu, Wenzhong

    2014-03-01

    Among structural health monitoring techniques, nonlinear ultrasonic spectroscopy methods are found to be effective diagnostic approach to detecting nonlinear damage such as fatigue crack, due to their sensitivity to incipient structural changes. In this paper, a nonlinear ultrasonic modulation method was developed to detect and locate a fatigue crack on an aluminum plate. The method is different with nonlinear wave modulation method which recognizes the modulation of low-frequency vibration and high-frequency ultrasonic wave; it recognizes the modulation of tone burst and high-frequency ultrasonic wave. In the experiment, a Hanning window modulated sinusoidal tone burst and a continuous sinusoidal excitation were simultaneously imposed on the PZT array which was bonded on the surface of an aluminum plate. The modulations of tone burst and continuous sinusoidal excitation was observed in different actuator-sensor paths, indicating the presence and location of fatigue crack. The results of experiments show that the proposed method is capable of detecting and locating the fatigue crack successfully.

  3. Heat pulse excitability of vestibular hair cells and afferent neurons

    Science.gov (United States)

    Brichta, Alan M.; Tabatabaee, Hessam; Boutros, Peter J.; Ahn, JoongHo; Della Santina, Charles C.; Poppi, Lauren A.; Lim, Rebecca

    2016-01-01

    In the present study we combined electrophysiology with optical heat pulse stimuli to examine thermodynamics of membrane electrical excitability in mammalian vestibular hair cells and afferent neurons. We recorded whole cell currents in mammalian type II vestibular hair cells using an excised preparation (mouse) and action potentials (APs) in afferent neurons in vivo (chinchilla) in response to optical heat pulses applied to the crista (ΔT ≈ 0.25°C per pulse). Afferent spike trains evoked by heat pulse stimuli were diverse and included asynchronous inhibition, asynchronous excitation, and/or phase-locked APs synchronized to each infrared heat pulse. Thermal responses of membrane currents responsible for APs in ganglion neurons were strictly excitatory, with Q10 ≈ 2. In contrast, hair cells responded with a mix of excitatory and inhibitory currents. Excitatory hair cell membrane currents included a thermoelectric capacitive current proportional to the rate of temperature rise (dT/dt) and an inward conduction current driven by ΔT. An iberiotoxin-sensitive inhibitory conduction current was also evoked by ΔT, rising in heat pulse excitability in vestibular sensory organs and provide quantitative methods for rational application of optical heat pulses to examine protein biophysics and manipulate cellular excitability. PMID:27226448

  4. GABAergic modulation of DC stimulation-induced motor cortex excitability shifts in humans.

    Science.gov (United States)

    Nitsche, Michael A; Liebetanz, David; Schlitterlau, Anett; Henschke, Undine; Fricke, Kristina; Frommann, Kai; Lang, Nicolas; Henning, Stefan; Paulus, Walter; Tergau, Frithjof

    2004-05-01

    Weak transcranial DC stimulation (tDCS) of the human motor cortex results in excitability shifts during and after the end of stimulation, which are most probably localized intracortically. Anodal stimulation enhances excitability, whereas cathodal stimulation reduces it. Although the after-effects of tDCS are NMDA receptor-dependent, nothing is known about the involvement of additional receptors. Here we show that pharmacological strengthening of GABAergic inhibition modulates selectively the after-effects elicited by anodal tDCS. Administration of the GABA(A) receptor agonist lorazepam resulted in a delayed, but then enhanced and prolonged anodal tDCS-induced excitability elevation. The initial absence of an excitability enhancement under lorazepam is most probably caused by a loss of the anodal tDCS-generated intracortical diminution of inhibition and enhancement of facilitation, which occurs without pharmacological intervention. The reasons for the late-occurring excitability enhancement remain unclear. Because intracortical inhibition and facilitation are not changed in this phase compared with pre-tDCS values, excitability changes originating from remote cortical or subcortical areas could be involved.

  5. Development and Implementation of Biological Circuits Using Excitable and Non-Excitable Cells

    Energy Technology Data Exchange (ETDEWEB)

    Casasnovas-Orus, V.; Gomez-Cid, L.; Hernandez-Romero, I.; Fuentes, L.; Guillem, M.S.; Atienza, F.; Fernandez-Aviles, F.; Climent, A.M.

    2016-07-01

    Compared to conventional computation systems, living beings require reduced power and raw materials consumption, inviting to explore the concept of biological circuits. In this project, a proof-of-concept of logical biocircuits using cell patterns has been developed. These were based upon differential ionic communication between cells, being the cells types used excitable and non-excitable, modeled by cardiomyocytes and fibroblasts correspondingly. To begin, patterns for the basic logic computation blocks were designed, including the OR gate, AND gate and logic memory. The designs were evaluated with mathematical models and in vitro experiments. Results of mathematical modeling indicated that theoretical approval of the biocircuit function. Regarding in vitro biocircuit implementation, three different selective cell localization techniques proved useful for the pattern creation. Evaluation with optical mapping confirmed the operation of the OR gate and logic memory. More resolution in the cell placement strategy will be needed to observe the proper AND gate operation. Thus, fine-tuning of the implementation process will enable the construction of more complex biocircuits that will take on clinical applications relating to electric stimulation of tissues and programmed drug delivery. (Author)

  6. Sound-by-sound thalamic stimulation modulates midbrain auditory excitability and relative binaural sensitivity in frogs.

    Science.gov (United States)

    Ponnath, Abhilash; Farris, Hamilton E

    2014-01-01

    Descending circuitry can modulate auditory processing, biasing sensitivity to particular stimulus parameters and locations. Using awake in vivo single unit recordings, this study tested whether electrical stimulation of the thalamus modulates auditory excitability and relative binaural sensitivity in neurons of the amphibian midbrain. In addition, by using electrical stimuli that were either longer than the acoustic stimuli (i.e., seconds) or presented on a sound-by-sound basis (ms), experiments addressed whether the form of modulation depended on the temporal structure of the electrical stimulus. Following long duration electrical stimulation (3-10 s of 20 Hz square pulses), excitability (spikes/acoustic stimulus) to free-field noise stimuli decreased by 32%, but returned over 600 s. In contrast, sound-by-sound electrical stimulation using a single 2 ms duration electrical pulse 25 ms before each noise stimulus caused faster and varied forms of modulation: modulation lasted sound-by-sound electrical stimulation varied between different acoustic stimuli, including for different male calls, suggesting modulation is specific to certain stimulus attributes. For binaural units, modulation depended on the ear of input, as sound-by-sound electrical stimulation preceding dichotic acoustic stimulation caused asymmetric modulatory effects: sensitivity shifted for sounds at only one ear, or by different relative amounts for both ears. This caused a change in the relative difference in binaural sensitivity. Thus, sound-by-sound electrical stimulation revealed fast and ear-specific (i.e., lateralized) auditory modulation that is potentially suited to shifts in auditory attention during sound segregation in the auditory scene.

  7. Modulation of motor cortex excitability by physical similarity with an observed hand action.

    Directory of Open Access Journals (Sweden)

    Marie-Christine Désy

    Full Text Available The passive observation of hand actions is associated with increased motor cortex excitability, presumably reflecting activity within the human mirror neuron system (MNS. Recent data show that in-group ethnic membership increases motor cortex excitability during observation of culturally relevant hand gestures, suggesting that physical similarity with an observed body part may modulate MNS responses. Here, we ask whether the MNS is preferentially activated by passive observation of hand actions that are similar or dissimilar to self in terms of sex and skin color. Transcranial magnetic stimulation-induced motor evoked potentials were recorded from the first dorsal interosseus muscle while participants viewed videos depicting index finger movements made by female or male participants with black or white skin color. Forty-eight participants equally distributed in terms of sex and skin color participated in the study. Results show an interaction between self-attributes and physical attributes of the observed hand in the right motor cortex of female participants, where corticospinal excitability is increased during observation of hand actions in a different skin color than that of the observer. Our data show that specific physical properties of an observed action modulate motor cortex excitability and we hypothesize that in-group/out-group membership and self-related processes underlie these effects.

  8. Modulation of visual cortical excitability by working memory: effect of luminance contrast of mental imagery

    Directory of Open Access Journals (Sweden)

    Zaira eCattaneo

    2011-02-01

    Full Text Available Although much is known about the impact of stimulus properties such as luminance contrast, spatial frequency and orientation on visually evoked neural activity, much less is known about how they modulate neural activity when they are properties of a mental image held in working memory (WM. Here we addressed this question by investigating how a parametric manipulation of an imagined stimulus attribute affects neuronal excitability in the early visual cortex. We manipulated luminance contrast, a stimulus property known to strongly affect the magnitude of neuronal responses in early visual areas. Luminance contrast modulated neuronal excitability, as assessed by the frequency of phosphenes induced by transcranial magnetic stimulation (TMS with the exact nature of this modulation depending on TMS intensity. These results point to a strong overlap in the neuronal processes underlying visual perception and mental imagery: not only does WM maintenance selectively engage neurons which are tuned to the maintained attribute (as has previously been shown, but the extent to which those neurons are activated depends on the luminance contrast (as is the case with visually-evoked responses. From a methodological viewpoint, these results suggest that assessment of visual cortical excitability using TMS is affected by the TMS intensity used to probe the neuronal population.

  9. Heat pulse excitability of vestibular hair cells and afferent neurons.

    Science.gov (United States)

    Rabbitt, Richard D; Brichta, Alan M; Tabatabaee, Hessam; Boutros, Peter J; Ahn, JoongHo; Della Santina, Charles C; Poppi, Lauren A; Lim, Rebecca

    2016-08-01

    In the present study we combined electrophysiology with optical heat pulse stimuli to examine thermodynamics of membrane electrical excitability in mammalian vestibular hair cells and afferent neurons. We recorded whole cell currents in mammalian type II vestibular hair cells using an excised preparation (mouse) and action potentials (APs) in afferent neurons in vivo (chinchilla) in response to optical heat pulses applied to the crista (ΔT ≈ 0.25°C per pulse). Afferent spike trains evoked by heat pulse stimuli were diverse and included asynchronous inhibition, asynchronous excitation, and/or phase-locked APs synchronized to each infrared heat pulse. Thermal responses of membrane currents responsible for APs in ganglion neurons were strictly excitatory, with Q10 ≈ 2. In contrast, hair cells responded with a mix of excitatory and inhibitory currents. Excitatory hair cell membrane currents included a thermoelectric capacitive current proportional to the rate of temperature rise (dT/dt) and an inward conduction current driven by ΔT An iberiotoxin-sensitive inhibitory conduction current was also evoked by ΔT, rising in protein biophysics and manipulate cellular excitability. Copyright © 2016 the American Physiological Society.

  10. Use of modulated excitation signals in ultrasound. Part I: Basic concepts and expected benefits

    DEFF Research Database (Denmark)

    Misaridis, Thanassis; Jensen, Jørgen Arendt

    2005-01-01

    This paper, the first from a series of three papers on the application of coded excitation signals in medical ultrasound, discusses the basic principles and ultrasound-related problems of pulse compression. The concepts of signal modulation and matched filtering are given, and a simple model...... of attenuation relates the matched filter response with the ambiguity function, known from radar. Based on this analysis and the properties of the ambiguity function, the selection of coded waveforms suitable for ultrasound imaging is discussed. It is shown that linear frequency modulation (FM) signals have...... that in the case of linear FM signals, a SNR improvement of 12 to 18 dB can be expected for large imaging depths in attenuating media, without any depth-dependent filter compensation. In contrast, nonlinear FM modulation and binary codes are shown to give a SNR improvement of only 4 to 9 dB when processed...

  11. An unavoidable modulation? Sensory attention and human primary motor cortex excitability.

    Science.gov (United States)

    Ruge, Diane; Muggleton, Neil; Hoad, Damon; Caronni, Antonio; Rothwell, John C

    2014-09-01

    The link between basic physiology and its modulation by cognitive states, such as attention, is poorly understood. A significant association becomes apparent when patients with movement disorders describe experiences with changing their attention focus and the fundamental effect that this has on their motor symptoms. Moreover, frequently used mental strategies for treating such patients, e.g. with task-specific dystonia, widely lack laboratory-based knowledge about physiological mechanisms. In this largely unexplored field, we looked at how the locus of attention, when it changed between internal (locus hand) and external (visual target), influenced excitability in the primary motor cortex (M1) in healthy humans. Intriguingly, both internal and external attention had the capacity to change M1 excitability. Both led to a reduced stimulation-induced GABA-related inhibition and a change in motor evoked potential size, i.e. an overall increased M1 excitability. These previously unreported findings indicated: (i) that cognitive state differentially interacted with M1 physiology, (ii) that our view of distraction (attention locus shifted towards external or distant location), which is used as a prevention or management strategy for use-dependent motor disorders, is too simple and currently unsupported for clinical application, and (iii) the physiological state reached through attention modulation represents an alternative explanation for frequently reported electrophysiology findings in neuropsychiatric disorders, such as an aberrant inhibition. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  12. Modulation of Corticospinal Excitability Depends on the Pattern of Mechanical Tactile Stimulation

    Directory of Open Access Journals (Sweden)

    Sho Kojima

    2018-01-01

    Full Text Available We investigated the effects of different patterns of mechanical tactile stimulation (MS on corticospinal excitability by measuring the motor-evoked potential (MEP. This was a single-blind study that included nineteen healthy subjects. MS was applied for 20 min to the right index finger. MS intervention was defined as simple, lateral, rubbing, vertical, or random. Simple intervention stimulated the entire finger pad at the same time. Lateral intervention stimulated with moving between left and right on the finger pad. Rubbing intervention stimulated with moving the stimulus probe, fixed by protrusion pins. Vertical intervention stimulated with moving in the forward and backward directions on the finger pad. Random intervention stimulated to finger pad with either row protrudes. MEPs were measured in the first dorsal interosseous muscle to transcranial magnetic stimulation of the left motor cortex before, immediately after, and 5–20 min after intervention. Following simple intervention, MEP amplitudes were significantly smaller than preintervention, indicating depression of corticospinal excitability. Following lateral, rubbing, and vertical intervention, MEP amplitudes were significantly larger than preintervention, indicating facilitation of corticospinal excitability. The modulation of corticospinal excitability depends on MS patterns. These results contribute to knowledge regarding the use of MS as a neurorehabilitation tool to neurological disorder.

  13. Modulation of Corticospinal Excitability Depends on the Pattern of Mechanical Tactile Stimulation.

    Science.gov (United States)

    Kojima, Sho; Onishi, Hideaki; Miyaguchi, Shota; Kotan, Shinichi; Sasaki, Ryoki; Nakagawa, Masaki; Kirimoto, Hikari; Tamaki, Hiroyuki

    2018-01-01

    We investigated the effects of different patterns of mechanical tactile stimulation (MS) on corticospinal excitability by measuring the motor-evoked potential (MEP). This was a single-blind study that included nineteen healthy subjects. MS was applied for 20 min to the right index finger. MS intervention was defined as simple, lateral, rubbing, vertical, or random. Simple intervention stimulated the entire finger pad at the same time. Lateral intervention stimulated with moving between left and right on the finger pad. Rubbing intervention stimulated with moving the stimulus probe, fixed by protrusion pins. Vertical intervention stimulated with moving in the forward and backward directions on the finger pad. Random intervention stimulated to finger pad with either row protrudes. MEPs were measured in the first dorsal interosseous muscle to transcranial magnetic stimulation of the left motor cortex before, immediately after, and 5-20 min after intervention. Following simple intervention, MEP amplitudes were significantly smaller than preintervention, indicating depression of corticospinal excitability. Following lateral, rubbing, and vertical intervention, MEP amplitudes were significantly larger than preintervention, indicating facilitation of corticospinal excitability. The modulation of corticospinal excitability depends on MS patterns. These results contribute to knowledge regarding the use of MS as a neurorehabilitation tool to neurological disorder.

  14. Time dependence of resonance γ-radiation modulated by acoustic excitations

    International Nuclear Information System (INIS)

    Mkrtchyan, A.R.; Arakelyan, A.R.; Gabrielyan, R.G.; Kocharyan, L.A.; Grigoryan, G.R.; Slavinskii, M.M.

    1984-01-01

    Experimental investigations of the time dependence of the γ-resonance absorption line intensity in case of modulation by acoustic waves are presented. 57 Co was used as source and a stainless steel foil was chosen as an absorber. The time dependences of the counting rate of the resonant γ-quanta corresponding to excitations with 3400 Hz and with 1.5 or 7 V at the vibrosystem transducer are plotted. The measurements show that the method has principal advantages over the conventional Moessbauer spectroscopy

  15. 60-GHz integrated-circuit high data rate quadriphase shift keying exciter and modulator

    Science.gov (United States)

    Grote, A.; Chang, K.

    1984-01-01

    An integrated-circuit quadriphase shift keying (QPSK) exciter and modulator have demonstrated excellent performance directly modulating a carrier frequency of 60 GHz with an output phase error of less than 3 degrees and maximum amplitude error of 0.5 dB. The circuit consists of a 60-GHz Gunn VCO phase-locked to a low-frequency reference source, a 4th subharmonic mixer, and a QPSK modlator packaged into a small volume of 1.8 x 2.5 x 0.35 in. The use of microstrip has the advantages of small size, light-weight, and low-cost fabrication. The unit has the potential for multigigabit data rate applications.

  16. Cell shunt resistance and photovoltaic module performance

    Energy Technology Data Exchange (ETDEWEB)

    McMahon, T.J.; Basso, T.S.; Rummel, S.R. [National Renewable Energy Lab., Golden, CO (United States)

    1996-05-01

    Shunt resistance of cells in photovoltaic modules can affect module power output and could indicate flawed manufacturing processes and reliability problems. The authors describe a two-terminal diagnostic method to directly measure the shunt resistance of individual cells in a series-connected module non-intrusively, without deencapsulation. Peak power efficiency vs. light intensity was measured on a 12-cell, series-connected, single crystalline module having relatively high cell shunt resistances. The module was remeasured with 0.5-, 1-, and 2-ohm resistors attached across each cell to simulate shunt resistances of several emerging technologies. Peak power efficiencies decreased dramatically at lower light levels. Using the PSpice circuit simulator, the authors verified that cell shunt and series resistances can indeed be responsible for the observed peak power efficiency vs. intensity behavior. The authors discuss the effect of basic cell diode parameters, i.e., shunt resistance, series resistance, and recombination losses, on PV module performance as a function of light intensity.

  17. Primary Motor Cortex Excitability Is Modulated During the Mental Simulation of Hand Movement.

    Science.gov (United States)

    Hyde, Christian; Fuelscher, Ian; Lum, Jarrad A G; Williams, Jacqueline; He, Jason; Enticott, Peter G

    2017-02-01

    It is unclear whether the primary motor cortex (PMC) is involved in the mental simulation of movement [i.e., motor imagery (MI)]. The present study aimed to clarify PMC involvement using a highly novel adaptation of the hand laterality task (HLT). Participants were administered single-pulse transcranial magnetic stimulation (TMS) to the hand area of the left PMC (hPMC) at either 50 ms, 400 ms, or 650 ms post stimulus presentation. Motor-evoked potentials (MEPs) were recorded from the right first dorsal interosseous via electromyography. To avoid the confound of gross motor response, participant response (indicating left or right hand) was recorded via eye tracking. Participants were 22 healthy adults (18 to 36 years), 16 whose behavioral profile on the HLT was consistent with the use of a MI strategy (MI users). hPMC excitability increased significantly during HLT performance for MI users, evidenced by significantly larger right hand MEPs following single-pulse TMS 50 ms, 400 ms, and 650 ms post stimulus presentation relative to baseline. Subsequent analysis showed that hPMC excitability was greater for more complex simulated hand movements, where hand MEPs at 50 ms were larger for biomechanically awkward movements (i.e., hands requiring lateral rotation) compared to simpler movements (i.e., hands requiring medial rotation). These findings provide support for the modulation of PMC excitability during the HLT attributable to MI, and may indicate a role for the PMC during MI. (JINS, 2017, 23, 185-193).

  18. Corticospinal and Spinal Excitabilities Are Modulated during Motor Imagery Associated with Somatosensory Electrical Nerve Stimulation

    Directory of Open Access Journals (Sweden)

    E. Traverse

    2018-01-01

    Full Text Available Motor imagery (MI, the mental simulation of an action, influences the cortical, corticospinal, and spinal levels, despite the lack of somatosensory afferent feedbacks. The aim of this study was to analyze the effect of MI associated with somatosensory stimulation (SS on the corticospinal and spinal excitabilities. We used transcranial magnetic stimulation and peripheral nerve stimulation to induce motor-evoked potentials (MEP and H-reflexes, respectively, in soleus and medialis gastrocnemius (MG muscles of the right leg. Twelve participants performed three tasks: (1 MI of submaximal plantar flexion, (2 SS at 65 Hz on the posterior tibial nerve with an intensity below the motor threshold, and (3 MI + SS. MEP and H-reflex amplitudes were recorded before, during, and after the tasks. Our results confirmed that MI increased corticospinal excitability in a time-specific manner. We found that MI+SS tended to potentiate MEP amplitude of the MG muscle compared to MI alone. We confirmed that SS decreased spinal excitability, and this decrease was partially compensated when combined with MI, especially for the MG muscle. The increase of CSE could be explained by a modulation of the spinal inhibitions induced by SS, depending on the amount of afferent feedbacks.

  19. Chirped or time modulated excitation compared to short pulses for photoacoustic imaging in acoustic attenuating media

    Science.gov (United States)

    Burgholzer, P.; Motz, C.; Lang, O.; Berer, T.; Huemer, M.

    2018-02-01

    In photoacoustic imaging, optically generated acoustic waves transport the information about embedded structures to the sample surface. Usually, short laser pulses are used for the acoustic excitation. Acoustic attenuation increases for higher frequencies, which reduces the bandwidth and limits the spatial resolution. One could think of more efficient waveforms than single short pulses, such as pseudo noise codes, chirped, or harmonic excitation, which could enable a higher information-transfer from the samples interior to its surface by acoustic waves. We used a linear state space model to discretize the wave equation, such as the Stoke's equation, but this method could be used for any other linear wave equation. Linear estimators and a non-linear function inversion were applied to the measured surface data, for onedimensional image reconstruction. The proposed estimation method allows optimizing the temporal modulation of the excitation laser such that the accuracy and spatial resolution of the reconstructed image is maximized. We have restricted ourselves to one-dimensional models, as for higher dimensions the one-dimensional reconstruction, which corresponds to the acoustic wave without attenuation, can be used as input for any ultrasound imaging method, such as back-projection or time-reversal method.

  20. Selective Excitation of Window and Buffer Layers in Chalcopyrite Devices and Modules

    Energy Technology Data Exchange (ETDEWEB)

    Glynn, Stephen [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Repins, Ingrid L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Burst, James M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Beall, Carolyn L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bowers, Karen A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Mansfield, Lorelle M [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-02-02

    Window and buffer layers in chalcopyrite devices are well known to affect junctions, conduction, and photo-absorption properties of the device. Some of these layers, particularly 'buffers,' which are deposited directly on top of the absorber, exhibit metastable effects upon exposure to light. Thus, to understand device performance and/or metastability, it is sometimes desirable to selectively excite different layers in the device stack. Absorption characteristics of various window and buffer layers used in chalcopyrite devices are measured. These characteristics are compared with emission spectra of common and available light sources that might be used to optically excite such layers. Effects of the window and buffer absorption on device quantum efficiency and metastability are discussed. For the case of bath-deposited Zn(O,S) buffers, we conclude that this layer is not optically excited in research devices or modules. This provides a complimentary mechanism to the chemical differences that may cause long time constants (compared to devices with CdS buffers) associated with reaching a stable 'light-soaked' state.

  1. Flow angle dependent photoacoustic Doppler power spectra under intensity-modulated continuous wave laser excitation

    Directory of Open Access Journals (Sweden)

    Yu Tong

    2016-02-01

    Full Text Available Photoacoustic Doppler (PAD power spectra showing an evident Doppler shift represent the major characteristics of the continuous wave-excited or burst wave-excited versions of PAD flow measurements. In this paper, the flow angle dependences of the PAD power spectra are investigated using an experiment setup that was established based on intensity-modulated continuous wave laser excitation. The setup has an overall configuration that is similar to a previously reported configuration, but is more sophisticated in that it accurately aligns the laser illumination with the ultrasound detection process, and in that it picks up the correct sample position. In the analysis of the power spectra data, we find that the background power spectra can be extracted by combining the output signals from the two channels of the lock-in amplifier, which is very useful for identification of the PAD power spectra. The power spectra are presented and analyzed in opposite flow directions, at different flow speeds, and at different flow angles. The power spectra at a 90° flow angle show the unique properties of symmetrical shapes due to PAD broadening. For the other flow angles, the smoothed power spectra clearly show a flow angle cosine relationship.

  2. Divalent cations as modulators of neuronal excitability: Emphasis on copper and zinc

    Directory of Open Access Journals (Sweden)

    RICARDO DELGADO

    2006-01-01

    Full Text Available Based on indirect evidence, a role for synaptically released copper and zinc as modulators of neuronal activity has been proposed. To test this proposal directly, we studied the effect of copper, zinc, and other divalent cations on voltage-dependent currents in dissociated toad olfactory neurons and on their firing rate induced by small depolarizing currents. Divalent cations in the nanomolar range sped up the activation kinetics and increased the amplitude of the inward sodium current. In the micromolar range, they caused a dose dependent inhibition of the inward Na+ and Ca2+ currents (I Na and I Ca and reduced de amplitude of the Ca2+-dependent K+ outward current (I Ca-K. On the other hand, the firing rate of olfactory neurons increased when exposed to nanomolar concentration of divalent cations and decreased when exposed to micromolar concentrations. This biphasic effect of divalent cations on neuronal excitability may be explained by the interaction of these ions with high and low affinity sites in voltage-gated channels. Our results support the idea that these ions are normal modulators of neuronal excitability

  3. Excitation of large-amplitude parametric resonance by the mechanical stiffness modulation of a microstructure

    International Nuclear Information System (INIS)

    Krylov, Slava; Gerson, Yuval; Nachmias, Tali; Keren, Uri

    2010-01-01

    In this work we report on an approach allowing efficient parametric excitation of large-amplitude stable oscillations of a microstructure operated by a parallel-plate electrode, and present results of a theoretical and experimental investigation of the device. The frame-type structure, fabricated from a silicon on insulator (SOI) substrate using deep reactive ion etching (DRIE), consists a pair of cantilever-type suspensions connected at their ends by a link. The time-varying electrostatic force applied to the link by a parallel-plate electrode is transformed into a periodic tension of the beams, resulting in the modulation of their flexural stiffness and consequently the mechanical parametric excitation of the structure. The lateral compliance of the beams allows for large-amplitude in-plane oscillations in the direction parallel to the electrode while high axial stiffness prevents undesirable instabilities. The lumped model of the device, considered as an assembly of geometrically nonlinear massless flexures and a rigid massive link and built using the Rayleigh–Ritz method, predicted the feasibility of the excitation approach. The fabricated devices were operated in ambient air conditions by a combination of a steady (dc) and time-dependent (ac) components of voltage and the large-amplitude responses, up to 75 µm, in the vicinity of the principal parametric and primary resonances were registered by means of video acquisition and image processing. The shapes of the experimental resonant curves were consistent with those predicted by the model. The location and size of the instability regions on the frequency–voltage plane (parametric tongues) were quantitatively in good agrement with the model results. Theoretical and experimental results indicate that the suggested approach can be efficiently used for excitation of various types of microdevices where stable resonant operation combined with robustness and large vibrational amplitudes are desirable

  4. Observing back pain provoking lifting actions modulates corticomotor excitability of the observer's primary motor cortex.

    Science.gov (United States)

    Lehner, Rea; Meesen, Raf; Wenderoth, Nicole

    2017-07-01

    Observing another person experiencing exogenously inflicted pain (e.g. by a sharp object penetrating a finger) modulates the excitability of the observer' primary motor cortex (M1). By contrast, far less is known about the response to endogenously evoked pain such as sudden back pain provoked by lifting a heavy object. Here, participants (n=26) observed the lifting of a heavy object. During this action the actor (1) flexed and extended the legs (LEG), (2) flexed and extended the back (BACK) or (3) flexed and extended the back which caused visible pain (BACKPAIN). Corticomotor excitability was measured by applying a single transcranial magnetic stimulation pulse to the M1 representation of the muscle erector spinae and participants scored their perception of the actor's pain on the numeric pain rating scale (NPRS). The participants scored vicarious pain as highest during the BACKPAIN condition and lowest during the LEG condition. MEP size was significantly lower for the LEG than the BACK and BACKPAIN condition. Although we found no statistical difference in the motor-evoked potential (MEP) size between the conditions BACK and BACKPAIN, there was a significant correlation between the difference in NPRS scores between the conditions BACKPAIN and BACK and the difference in MEP size between these conditions. Participants who believed the vicarious pain to be much stronger in the BACKPAIN than in the BACK condition also exhibited higher MEPs for the BACKPAIN than the BACK condition. Our results indicate that observing how others lift heavy objects facilitates motor representations of back muscles in the observer. Modulation occurs in a movement-specific manner and is additionally modulated by the extent to which the participants perceived the actor's pain. Our findings suggest that movement observation might be a promising paradigm to study the brain's response to back pain. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Analytical formulation for modulation of time-resolved dynamical Franz-Keldysh effect by electron excitation in dielectrics

    Science.gov (United States)

    Otobe, T.

    2017-12-01

    Analytical formulation of subcycle modulation (SCM) of dielectrics including electron excitation is presented. The SCM is sensitive to not only the time-resolved dynamical Franz-Keldysh effect (Tr-DFKE) [T. Otobe et al., Phys. Rev. B 93, 045124 (2016), 10.1103/PhysRevB.93.045124], which is the nonlinear response without the electron excitation, but also the excited electrons. The excited electrons enhance the modulation with even harmonics of pump laser frequency, and generate the odd-harmonics components. The new aspect of SCM is a consequence of (i) the interference between the electrons excited by the pump laser and those excited by the probe-pulse laser and (ii) oscillation of the generated wave packed by the pump laser. When the probe- and pump-pulse polarizations are parallel, the enhancement of the even harmonics and the generation of the odd-harmonics modulation appear. However, if the polarizations are orthogonal, the effect arising from the electron excitations becomes weak. By comparing the parabolic and cosine band models, I found that the electrons under the intense laser field move as quasifree particles.

  6. Transversely Excited Multipass Photoacoustic Cell Using Electromechanical Film as Microphone

    Directory of Open Access Journals (Sweden)

    Jaakko Saarela

    2010-05-01

    Full Text Available A novel multipass photoacoustic cell with five stacked electromechanical films as a microphone has been constructed, tested and characterized. The photoacoustic cell is an open rectangular structure with two steel plates facing each other. The longitudinal acoustic resonances are excited transversely in an optical multipass configuration. A detection limit of 22 ppb (10−9 was achieved for flowing NO2 in N2 at normal pressure by using the maximum of 70 laser beams between the resonator plates. The corresponding minimum detectable absorption and the normalized noise-equivalent absorption coefficients were 2:2 × 10−7 cm−1 and 3:2 × 10−9 cm−1WHz−1/2, respectively.

  7. Heat loss analysis-based design of a 12 MW wind power generator module having an HTS flux pump exciter

    International Nuclear Information System (INIS)

    Sung, Hae-Jin; Go, Byeong-Soo; Jiang, Zhenan; Park, Minwon; Yu, In-Keun

    2016-01-01

    Highlights: • A large-scale HTS generator module has been suggested to avoid issues such as a huge vacuum vessel and higher reliability. • The challenging heat loss analysis of a large-scale HTS generator has successfully been performed, enabling the design of an optimal support structure having a total heat loss of 43 W/400 kW. • The results prove the potential of a large-scale superconducting wind-power generator to operate efficiently, and support further development of the concept. - Abstract: The development of an effective high-temperature superconducting (HTS) generator is currently a research focus; however, the reduction of heat loss of a large-scale HTS generator is a challenge. This study deals with a heat loss analysis-based design of a 12 MW wind power generator module having an HTS flux pump exciter. The generator module consists of an HTS rotor of the generator and an HTS flux pump exciter. The specifications of the module were described, and the detailed configuration of the module was illustrated. For the heat loss analysis of the module, the excitation loss of the flux pump exciter, eddy current loss of all of the structures in the module, radiation loss, and conduction loss of an HTS coil supporter were assessed using a 3D finite elements method program. In the case of the conduction loss, different types of the supporters were compared to find out the supporter of the lowest conduction loss in the module. The heat loss analysis results of the module were reflected in the design of the generator module and discussed in detail. The results will be applied to the design of large-scale superconducting generators for wind turbines including a cooling system.

  8. Heat loss analysis-based design of a 12 MW wind power generator module having an HTS flux pump exciter

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Hae-Jin, E-mail: haejin0216@gmail.com [Changwon National University, 20 Changwondaehak-ro, Changwon, 641-773 (Korea, Republic of); Go, Byeong-Soo [Changwon National University, 20 Changwondaehak-ro, Changwon, 641-773 (Korea, Republic of); Jiang, Zhenan [Robinson Research Institute, Victoria University of Wellington, PO Box 33436 (New Zealand); Park, Minwon [Changwon National University, 20 Changwondaehak-ro, Changwon, 641-773 (Korea, Republic of); Yu, In-Keun, E-mail: yuik@changwon.ac.kr [Changwon National University, 20 Changwondaehak-ro, Changwon, 641-773 (Korea, Republic of)

    2016-11-15

    Highlights: • A large-scale HTS generator module has been suggested to avoid issues such as a huge vacuum vessel and higher reliability. • The challenging heat loss analysis of a large-scale HTS generator has successfully been performed, enabling the design of an optimal support structure having a total heat loss of 43 W/400 kW. • The results prove the potential of a large-scale superconducting wind-power generator to operate efficiently, and support further development of the concept. - Abstract: The development of an effective high-temperature superconducting (HTS) generator is currently a research focus; however, the reduction of heat loss of a large-scale HTS generator is a challenge. This study deals with a heat loss analysis-based design of a 12 MW wind power generator module having an HTS flux pump exciter. The generator module consists of an HTS rotor of the generator and an HTS flux pump exciter. The specifications of the module were described, and the detailed configuration of the module was illustrated. For the heat loss analysis of the module, the excitation loss of the flux pump exciter, eddy current loss of all of the structures in the module, radiation loss, and conduction loss of an HTS coil supporter were assessed using a 3D finite elements method program. In the case of the conduction loss, different types of the supporters were compared to find out the supporter of the lowest conduction loss in the module. The heat loss analysis results of the module were reflected in the design of the generator module and discussed in detail. The results will be applied to the design of large-scale superconducting generators for wind turbines including a cooling system.

  9. The Use and Abuse of Transcranial Magnetic Stimulation to Modulate Corticospinal Excitability in Humans.

    Directory of Open Access Journals (Sweden)

    Martin E Héroux

    Full Text Available The magnitude and direction of reported physiological effects induced using transcranial magnetic stimulation (TMS to modulate human motor cortical excitability have proven difficult to replicate routinely. We conducted an online survey on the prevalence and possible causes of these reproducibility issues. A total of 153 researchers were identified via their publications and invited to complete an anonymous internet-based survey that asked about their experience trying to reproduce published findings for various TMS protocols. The prevalence of questionable research practices known to contribute to low reproducibility was also determined. We received 47 completed surveys from researchers with an average of 16.4 published papers (95% CI 10.8-22.0 that used TMS to modulate motor cortical excitability. Respondents also had a mean of 4.0 (2.5-5.7 relevant completed studies that would never be published. Across a range of TMS protocols, 45-60% of respondents found similar results to those in the original publications; the other respondents were able to reproduce the original effects only sometimes or not at all. Only 20% of respondents used formal power calculations to determine study sample sizes. Others relied on previously published studies (25%, personal experience (24% or flexible post-hoc criteria (41%. Approximately 44% of respondents knew researchers who engaged in questionable research practices (range 30–81%, yet only 18% admitted to engaging in them (range 6–38% [corrected]. These practices included screening subjects to find those that respond in a desired way to a TMS protocol, selectively reporting results and rejecting data based on a gut feeling. In a sample of 56 published papers that were inspected, not a single questionable research practice was reported. Our survey revealed that approximately 50% of researchers are unable to reproduce published TMS effects. Researchers need to start increasing study sample size and eliminating

  10. Modulation of synaptic potentials and cell excitability by dendritic ...

    Indian Academy of Sciences (India)

    The nucleus accumbens (NAc), a critical structure of the brain reward circuit, is implicated in normal goal-directed behaviour ... limbic and extrapyramidal motor systems (Mogenson et al. .... A further motivation for exploring the effects of the KIR.

  11. Gonadal Steroids: Effects on Excitability of Hippocampal Pyramidal Cells

    Science.gov (United States)

    Teyler, Timothy J.; Vardaris, Richard M.; Lewis, Deborah; Rawitch, Allen B.

    1980-08-01

    Electrophysiological field potentials from hippocampal slices of rat brain show sex-linked differences in response to 1 × 10-10M concentrations of estradiol and testosterone added to the incubation medium. Slices from male rats show increased excitability to estradiol and not to testosterone. Slices from female rats are not affected by estradiol, but slices from female rats in diestrus show increased excitability in response to testosterone whereas slices from females in proestrus show decreased excitability.

  12. The electrical behaviour of an excitable cell at different conditions

    International Nuclear Information System (INIS)

    El-Sayed, M.; Mohammed, A.M.

    1994-08-01

    The Hodgkin-Huxley, H-H, model has been modified, in this work, to study the electrical behaviour of an excitable cell due to changes in the permeability of K and Na ions (g k and g Na ), the simultaneous stochastic variations of g k and g Na , the current stimulus (Jstim) and the non-inactivation of Na-channel (NI - NaC). The amplitude and duration of the generated action potential (AP) was found to increase as g k increases, with the appearance of repetitive AP spikes in the range of 21.5 ≥ g k ≥ 3.5 while the K- and Na-currents (J k and J Na ) showed a pronounced decrease. On the other hand, the increase of g Na was accompanied by an increase in AP amplitudes and durations and also in J k and J Na with the appearance of a repetitive AP at 1400 ≥ g Na ≥ 189 ms/cm 2 whose frequency increases with the increase of g Na . Moreover, the stochastic variations in g k and g Na could generate a repetitive AP whose frequency could be changed either by changing the values of g k or g Na or both, and may represent an information carried by the sensory cells for example. The electrical behaviour of the simulated cell can also be affected by Jstim at different values of g k except at the range of 21.5 ≥ g k ≥ 3.5 ms/cm 2 and also depended on NI - NaC fraction. (author). 11 refs, 9 figs, 4 tabs

  13. Modulation of network excitability by persistent activity: how working memory affects the response to incoming stimuli.

    Directory of Open Access Journals (Sweden)

    Elisa M Tartaglia

    2015-02-01

    Full Text Available Persistent activity and match effects are widely regarded as neuronal correlates of short-term storage and manipulation of information, with the first serving active maintenance and the latter supporting the comparison between memory contents and incoming sensory information. The mechanistic and functional relationship between these two basic neurophysiological signatures of working memory remains elusive. We propose that match signals are generated as a result of transient changes in local network excitability brought about by persistent activity. Neurons more active will be more excitable, and thus more responsive to external inputs. Accordingly, network responses are jointly determined by the incoming stimulus and the ongoing pattern of persistent activity. Using a spiking model network, we show that this mechanism is able to reproduce most of the experimental phenomenology of match effects as exposed by single-cell recordings during delayed-response tasks. The model provides a unified, parsimonious mechanistic account of the main neuronal correlates of working memory, makes several experimentally testable predictions, and demonstrates a new functional role for persistent activity.

  14. C-Si solar cell modules

    International Nuclear Information System (INIS)

    Tomita, Takashi

    2005-01-01

    In order to meet the rapidly growing demand for solar power photovoltaic systems which is based on public consciousness of global environmental issues, SHARP has increased the production of solar cells and modules over 10-fold in the last 5 years. Silicon-based technologies are expected to be dominant in the coming decade. In the course of an increase of the annual production scale to 1000 MW, the efficiency of modules will be improved and the thickness of wafers will be decreased and all this will lead to a drastic price reduction of PV systems. (Author)

  15. Excitant and depressant drugs modulate effects of environment on brain weight and cholinesterases

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, E.L.; Rosenzweig, M.R.; Wu, S.Y.C.

    1973-01-01

    Certain excitant drugs can enhance the effects of enriched experience on weights of brain sections and on the activities of acetylcholinesterase and cholinesterase in the brain, and certain depressants can lessen the brain weight effects. Most experiments were performed with prepubertal male rats. Some rats were exposed in groups of 12 to an enriched environmental condition (EC), usually for 2 h per day and over a 30-day period; others remained in their individual home cages (HC) throughout. Some received a drug injection and others received a saline injection before the daily EC period; HC controls received similar injections. The drug injections had no significant effects on brain values of HC rats, but they altered effects of EC, probably by influencing the animals' reactions to the environment. Methamphetamine and d-amphetamine enhanced the EC effects; metrazol had small positive effects; and strychnine was without effects. Phenobarbital depressed the brain weight effects but increased the enzymatic effects. Use of methamphetamine made it possible to find EC effects with short daily periods (30 min) or with a shortened experimental duration (15 days). In experiments with adult rats, methamphetamine did not modulate the brain weight effects. The results of this study may bear on the use of stimulants to promote recovery from brain damage.

  16. Modulation of left primary motor cortex excitability after bimanual training and intermittent theta burst stimulation to left dorsal premotor cortex.

    Science.gov (United States)

    Neva, Jason L; Vesia, Michael; Singh, Amaya M; Staines, W Richard

    2014-03-15

    Bimanual visuomotor movement training (BMT) enhances the excitability of human preparatory premotor and primary motor (M1) cortices compared to unimanual movement. This occurs when BMT involves mirror symmetrical movements of both upper-limbs (in-phase) but not with non-symmetrical movements (anti-phase). The neural mechanisms mediating the effect of BMT is unclear, but may involve interhemispheric connections between homologous M1 representations as well as the dorsal premotor cortices (PMd). The purpose of this study is to assess how intermittent theta burst stimulation (iTBS) of the left PMd affects left M1 excitability, and the possible combined effects of iTBS to left PMd applied before a single session of BMT. Left M1 excitability was quantified using transcranial magnetic stimulation (TMS) in terms of both the amplitudes and spatial extent of motor evoked potentials (MEPs) for the extensor carpi radialis (ECR) before and multiple time points following (1) BMT, (2) iTBS to left PMd or (3) iTBS to left PMd and BMT. Although there was not a greater increase in either specific measure of M1 excitability due to the combination of the interventions, iTBS applied before BMT showed that both the spatial extent and global MEP amplitude for the ECR became larger in parallel, whereas the spatial extent was enhanced with BMT alone and global MEP amplitude was enhanced with iTBS to left PMd alone. These results suggest that the modulation of rapid functional M1 excitability associated with BMT and iTBS of the left PMd could operate under related early markers of neuro-plastic mechanisms, which may be expressed in concurrent and distinct patterns of M1 excitability. Critically, this work may guide rehabilitation training and stimulation techniques that modulate cortical excitability after brain injury. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Cell module and fuel conditioner development

    Science.gov (United States)

    Hoover, D. Q., Jr.

    1980-01-01

    Components for the first 5 cell stack (no cooling plates) of the MK-2 design were fabricated. Preliminary specfications and designs for the components of a 23 cell MK-1 stack with four DIGAS cooling plates were developed. The MK-2 was selected as a bench mark design and a preliminary design of the facilities required for high rate manufacture of fuel cell modules was developed. Two stands for testing 5 cell stacks were built and design work for modifying existing stands and building new stands for 23 and 80 cell stacks was initiated. Design and procurement of components and materials for the catalyst test stand were completed and construction initiated. Work on the specifications of pipeline gas, tap water and recovered water and definition of equipment required for treatment was initiated. An innovative geometry for the reformer was conceived and modifications of the computer program to be used in its design were stated.

  18. Milestones Toward 50% Efficient Solar Cell Modules

    Science.gov (United States)

    2007-09-01

    efficiency, both at solar cells and module level. The optical system consists of a tiled nonimaging concentrating system, coupled with a spectral...which combines a nonimaging optical concentrator (which does not require tracking and is called a static concentrator) with spectral splitting...DESIGN AND RESULTS The optical design is based on non-symmetric, nonimaging optics, tiled into an array. The central issues in the optical system

  19. Pulsed infrared radiation excites cultured neonatal spiral and vestibular ganglion neurons by modulating mitochondrial calcium cycling.

    Science.gov (United States)

    Lumbreras, Vicente; Bas, Esperanza; Gupta, Chhavi; Rajguru, Suhrud M

    2014-09-15

    Cochlear implants are currently the most effective solution for profound sensorineural hearing loss, and vestibular prostheses are under development to treat bilateral vestibulopathies. Electrical current spread in these neuroprostheses limits channel independence and, in some cases, may impair their performance. In comparison, optical stimuli that are spatially confined may result in a significant functional improvement. Pulsed infrared radiation (IR) has previously been shown to elicit responses in neurons. This study analyzes the response of neonatal rat spiral and vestibular ganglion neurons in vitro to IR (wavelength = 1,863 nm) using Ca(2+) imaging. Both types of neurons responded consistently with robust intracellular Ca(2+) ([Ca(2+)]i) transients that matched the low-frequency IR pulses applied (4 ms, 0.25-1 pps). Radiant exposures of ∼637 mJ/cm(2) resulted in continual neuronal activation. Temperature or [Ca(2+)] variations in the media did not alter the IR-evoked transients, ruling out extracellular Ca(2+) involvement or primary mediation by thermal effects on the plasma membrane. While blockage of Na(+), K(+), and Ca(2+) plasma membrane channels did not alter the IR-evoked response, blocking of mitochondrial Ca(2+) cycling with CGP-37157 or ruthenium red reversibly inhibited the IR-evoked [Ca(2+)]i transients. Additionally, the magnitude of the IR-evoked transients was dependent on ryanodine and cyclopiazonic acid-dependent Ca(2+) release. These results suggest that IR modulation of intracellular calcium cycling contributes to stimulation of spiral and vestibular ganglion neurons. As a whole, the results suggest selective excitation of neurons in the IR beam path and the potential of IR stimulation in future auditory and vestibular prostheses. Copyright © 2014 the American Physiological Society.

  20. Trace Fear Conditioning Differentially Modulates Intrinsic Excitability of Medial Prefrontal Cortex-Basolateral Complex of Amygdala Projection Neurons in Infralimbic and Prelimbic Cortices.

    Science.gov (United States)

    Song, Chenghui; Ehlers, Vanessa L; Moyer, James R

    2015-09-30

    Neuronal activity in medial prefrontal cortex (mPFC) is critical for the formation of trace fear memory, yet the cellular mechanisms underlying these memories remain unclear. One possibility involves the modulation of intrinsic excitability within mPFC neurons that project to the basolateral complex of amygdala (BLA). The current study used a combination of retrograde labeling and in vitro whole-cell patch-clamp recordings to examine the effect of trace fear conditioning on the intrinsic excitability of layer 5 mPFC-BLA projection neurons in adult rats. Trace fear conditioning significantly enhanced the intrinsic excitability of regular spiking infralimbic (IL) projection neurons, as evidenced by an increase in the number of action potentials after current injection. These changes were also associated with a reduction in spike threshold and an increase in h current. In contrast, trace fear conditioning reduced the excitability of regular spiking prelimbic (PL) projection neurons, through a learning-related decrease of input resistance. Interestingly, the amount of conditioned freezing was (1) positively correlated with excitability of IL-BLA projection neurons after conditioning and (2) negatively correlated with excitability of PL-BLA projection neurons after extinction. Trace fear conditioning also significantly enhanced the excitability of burst spiking PL-BLA projection neurons. In both regions, conditioning-induced plasticity was learning specific (observed in conditioned but not in pseudoconditioned rats), flexible (reversed by extinction), and transient (lasted extinction of trace fear conditioning. Significance statement: Frontal lobe-related function is vital for a variety of important behaviors, some of which decline during aging. This study involves a novel combination of electrophysiological recordings from fluorescently labeled mPFC-to-amygdala projection neurons in rats with acquisition and extinction of trace fear conditioning to determine how

  1. Photovoltaic Cells and Modules towards Terawatt Era

    Institute of Scientific and Technical Information of China (English)

    Vitezslav Benda

    2017-01-01

    Progresses in photovoltaic technologies over the past years are evident from the lower costs,the rising efficiency,to the great improvements in system reliability and yield.Cumulative installed power yearly growths were on an average more than 40% in the period from 2007 to 2016 and in 2016,the global cumulative photovoltaic power installed has reached 320 GWp.The level 0.5 TWp could be reached before 2020.The production processes in the solar industry still have great potential for optimization both wafer based and thin film technologies.Trends following from the present technology levels are discussed,also taking into account other parts of photovoltaic systems that influence the cost of electrical energy produced.Present developments in the three generations of photovoltaic modules are discussed along with the criteria for the selection of appropriate photovoltaic module manufacturing technologies.The wafer based crystalline silicon (c-silicon) technologies have the role of workhorse of present photovoltaic power generation,representing more than 90% of total module production.Further technology improvements have to be implemented without significantly increasing costs per unit,despite the necessarily more complex manufacturing processes involved.The tandem of c-silicon and thin film cells is very promising.Durability may be a limiting factor of this technology due to the dependence of the produced electricity cost on the module service time.

  2. Dynamic modulation of corticospinal excitability and short-latency afferent inhibition during onset and maintenance phase of selective finger movement.

    Science.gov (United States)

    Cho, Hyun Joo; Panyakaew, Pattamon; Thirugnanasambandam, Nivethida; Wu, Tianxia; Hallett, Mark

    2016-06-01

    During highly selective finger movement, corticospinal excitability is reduced in surrounding muscles at the onset of movement but this phenomenon has not been demonstrated during maintenance of movement. Sensorimotor integration may play an important role in selective movement. We sought to investigate how corticospinal excitability and short-latency afferent inhibition changes in active and surrounding muscles during onset and maintenance of selective finger movement. Using transcranial magnetic stimulation (TMS) and paired peripheral stimulation, input-output recruitment curve and short-latency afferent inhibition (SAI) were measured in the first dorsal interosseus and abductor digiti minimi muscles during selective index finger flexion. Motor surround inhibition was present only at the onset phase, but not at the maintenance phase of movement. SAI was reduced at onset but not at the maintenance phase of movement in both active and surrounding muscles. Our study showed dynamic changes in corticospinal excitability and sensorimotor modulation for active and surrounding muscles in different movement states. SAI does not appear to contribute to motor surround inhibition at the movement onset phase. Also, there seems to be different inhibitory circuit(s) other than SAI for the movement maintenance phase in order to delineate the motor output selectively when corticospinal excitability is increased in both active and surrounding muscles. This study enhances our knowledge of dynamic changes in corticospinal excitability and sensorimotor interaction in different movement states to understand normal and disordered movements. Published by Elsevier Ireland Ltd.

  3. Losses analysis of soft magnetic ring core under sinusoidal pulse width modulation (SPWM) and space vector pulse width modulation (SVPWM) excitations

    Science.gov (United States)

    Gao, Hezhe; Li, Yongjian; Wang, Shanming; Zhu, Jianguo; Yang, Qingxin; Zhang, Changgeng; Li, Jingsong

    2018-05-01

    Practical core losses in electrical machines differ significantly from those experimental results using the standardized measurement method, i.e. Epstein Frame method. In order to obtain a better approximation of the losses in an electrical machine, a simulation method considering sinusoidal pulse width modulation (SPWM) and space vector pulse width modulation (SVPWM) waveforms is proposed. The influence of the pulse width modulation (PWM) parameters on the harmonic components in SPWM and SVPWM is discussed by fast Fourier transform (FFT). Three-level SPWM and SVPWM are analyzed and compared both by simulation and experiment. The core losses of several ring samples magnetized by SPWM, SVPWM and sinusoidal alternating current (AC) are obtained. In addition, the temperature rise of the samples under SPWM, sinusoidal excitation are analyzed and compared.

  4. Wavelength-modulated spectroscopy of the sub-bandgap response of solar cell devices

    Energy Technology Data Exchange (ETDEWEB)

    Mandanirina, N.H., E-mail: s213514095@nmmu.ac.za; Botha, J.R.; Wagener, M.C.

    2016-01-01

    A wavelength-modulation setup for measuring the differential photo-response of a GaSb/GaAs quantum ring solar cell structure is reported. The pseudo-monochromatic wavelength is modulated at the output of a conventional monochromator by means of a vibrating slit mechanism. The vibrating slit was able to modulate the excitation wavelength up to 33 nm. The intensity of the light beam was kept constant through a unique flux correction module, designed and built in-house. The setup enabled measurements in the near-infrared range (from 1000 to 1300 nm), which is specifically used to probe the sub-band gap differential photo-response of GaAs solar cells.

  5. A Quantitative Analysis of Photovoltaic Modules Using Halved Cells

    Directory of Open Access Journals (Sweden)

    S. Guo

    2013-01-01

    Full Text Available In a silicon wafer-based photovoltaic (PV module, significant power is lost due to current transport through the ribbons interconnecting neighbour cells. Using halved cells in PV modules is an effective method to reduce the resistive power loss which has already been applied by some major PV manufacturers (Mitsubishi, BP Solar in their commercial available PV modules. As a consequence, quantitative analysis of PV modules using halved cells is needed. In this paper we investigate theoretically and experimentally the difference between modules made with halved and full-size solar cells. Theoretically, we find an improvement in fill factor of 1.8% absolute and output power of 90 mW for the halved cell minimodule. Experimentally, we find an improvement in fill factor of 1.3% absolute and output power of 60 mW for the halved cell module. Also, we investigate theoretically how this effect confers to the case of large-size modules. It is found that the performance increment of halved cell PV modules is even higher for high-efficiency solar cells. After that, the resistive loss of large-size modules with different interconnection schemes is analysed. Finally, factors influencing the performance and cost of industrial halved cell PV modules are discussed.

  6. Generation and customization of biosynthetic excitable tissues for electrophysiological studies and cell-based therapies.

    Science.gov (United States)

    Nguyen, Hung X; Kirkton, Robert D; Bursac, Nenad

    2018-05-01

    We describe a two-stage protocol to generate electrically excitable and actively conducting cell networks with stable and customizable electrophysiological phenotypes. Using this method, we have engineered monoclonally derived excitable tissues as a robust and reproducible platform to investigate how specific ion channels and mutations affect action potential (AP) shape and conduction. In the first stage of the protocol, we combine computational modeling, site-directed mutagenesis, and electrophysiological techniques to derive optimal sets of mammalian and/or prokaryotic ion channels that produce specific AP shape and conduction characteristics. In the second stage of the protocol, selected ion channels are stably expressed in unexcitable human cells by means of viral or nonviral delivery, followed by flow cytometry or antibiotic selection to purify the desired phenotype. This protocol can be used with traditional heterologous expression systems or primary excitable cells, and application of this method to primary fibroblasts may enable an alternative approach to cardiac cell therapy. Compared with existing methods, this protocol generates a well-defined, relatively homogeneous electrophysiological phenotype of excitable cells that facilitates experimental and computational studies of AP conduction and can decrease arrhythmogenic risk upon cell transplantation. Although basic cell culture and molecular biology techniques are sufficient to generate excitable tissues using the described protocol, experience with patch-clamp techniques is required to characterize and optimize derived cell populations.

  7. Do not resonate with actions: sentence polarity modulates cortico-spinal excitability during action-related sentence reading.

    Directory of Open Access Journals (Sweden)

    Marco Tullio Liuzza

    Full Text Available BACKGROUND: Theories of embodied language suggest that the motor system is differentially called into action when processing motor-related versus abstract content words or sentences. It has been recently shown that processing negative polarity action-related sentences modulates neural activity of premotor and motor cortices. METHODS AND FINDINGS: We sought to determine whether reading negative polarity sentences brought about differential modulation of cortico-spinal motor excitability depending on processing hand-action related or abstract sentences. Facilitatory paired-pulses Transcranial Magnetic Stimulation (pp-TMS was applied to the primary motor representation of the right-hand and the recorded amplitude of induced motor-evoked potentials (MEP was used to index M1 activity during passive reading of either hand-action related or abstract content sentences presented in both negative and affirmative polarity. Results showed that the cortico-spinal excitability was affected by sentence polarity only in the hand-action related condition. Indeed, in keeping with previous TMS studies, reading positive polarity, hand action-related sentences suppressed cortico-spinal reactivity. This effect was absent when reading hand action-related negative polarity sentences. Moreover, no modulation of cortico-spinal reactivity was associated with either negative or positive polarity abstract sentences. CONCLUSIONS: Our results indicate that grammatical cues prompting motor negation reduce the cortico-spinal suppression associated with affirmative action sentences reading and thus suggest that motor simulative processes underlying the embodiment may involve even syntactic features of language.

  8. Silicon dioxide etching process for fabrication of micro-optics employing pulse-modulated electron-beam-excited plasma

    International Nuclear Information System (INIS)

    Takeda, Keigo; Ohta, Takayuki; Ito, Masafumi; Hori, Masaru

    2006-01-01

    Silicon dioxide etching process employing a pulse-modulated electron-beam-excited plasma (EBEP) has been developed for a fabrication process of optical micro-electro-mechanical systems (MEMSs). Nonplanar dielectric materials were etched by using self-bias induced by the electron beam generating the plasma. In order to investigate the effect of pulse modulation on electron beam, plasma diagnostics were carried out in the EBEP employing C 4 F 8 gas diluted with Ar gas by using a Langmuir single probe and time resolved optical emission spectroscopy. It was found that the pulse-modulated EBEP has an excellent potential to reduce the plasma-induced thermal damage on a photoresist film on a substrate to get the uniform etching and the anisotropic SiO 2 etching in comparison with the conventional EBEP. The pulse-modulated EBEP enabled us to get the high etch rate of SiO 2 of 375 nm/min without any additional bias power supply. Furthermore, the microfabrication on the core area of optical fiber was realized. These results indicate that the pulse-modulated EBEP will be a powerful tool for the application to optical MEMS process

  9. Bidirectional Modulation of Intrinsic Excitability in Rat Prelimbic Cortex Neuronal Ensembles and Non-Ensembles after Operant Learning.

    Science.gov (United States)

    Whitaker, Leslie R; Warren, Brandon L; Venniro, Marco; Harte, Tyler C; McPherson, Kylie B; Beidel, Jennifer; Bossert, Jennifer M; Shaham, Yavin; Bonci, Antonello; Hope, Bruce T

    2017-09-06

    Learned associations between environmental stimuli and rewards drive goal-directed learning and motivated behavior. These memories are thought to be encoded by alterations within specific patterns of sparsely distributed neurons called neuronal ensembles that are activated selectively by reward-predictive stimuli. Here, we use the Fos promoter to identify strongly activated neuronal ensembles in rat prelimbic cortex (PLC) and assess altered intrinsic excitability after 10 d of operant food self-administration training (1 h/d). First, we used the Daun02 inactivation procedure in male FosLacZ-transgenic rats to ablate selectively Fos-expressing PLC neurons that were active during operant food self-administration. Selective ablation of these neurons decreased food seeking. We then used male FosGFP-transgenic rats to assess selective alterations of intrinsic excitability in Fos-expressing neuronal ensembles (FosGFP + ) that were activated during food self-administration and compared these with alterations in less activated non-ensemble neurons (FosGFP - ). Using whole-cell recordings of layer V pyramidal neurons in an ex vivo brain slice preparation, we found that operant self-administration increased excitability of FosGFP + neurons and decreased excitability of FosGFP - neurons. Increased excitability of FosGFP + neurons was driven by increased steady-state input resistance. Decreased excitability of FosGFP - neurons was driven by increased contribution of small-conductance calcium-activated potassium (SK) channels. Injections of the specific SK channel antagonist apamin into PLC increased Fos expression but had no effect on food seeking. Overall, operant learning increased intrinsic excitability of PLC Fos-expressing neuronal ensembles that play a role in food seeking but decreased intrinsic excitability of Fos - non-ensembles. SIGNIFICANCE STATEMENT Prefrontal cortex activity plays a critical role in operant learning, but the underlying cellular mechanisms are

  10. Physical activity modulates corticospinal excitability of the lower limb in young and old adults.

    Science.gov (United States)

    Hassanlouei, Hamidollah; Sundberg, Christopher W; Smith, Ashleigh E; Kuplic, Andrew; Hunter, Sandra K

    2017-08-01

    Aging is associated with reduced neuromuscular function, which may be due in part to altered corticospinal excitability. Regular physical activity (PA) may ameliorate these age-related declines, but the influence of PA on corticospinal excitability is unknown. The purpose of this study was to determine the influence of age, sex, and PA on corticospinal excitability by comparing the stimulus-response curves of motor evoked potentials (MEP) in 28 young (22.4 ± 2.2 yr; 14 women and 14 men) and 50 old adults (70.2 ± 6.1 yr; 22 women and 28 men) who varied in activity levels. Transcranial magnetic stimulation was used to elicit MEPs in the active vastus lateralis muscle (10% maximal voluntary contraction) with 5% increments in stimulator intensity until the maximum MEP amplitude. Stimulus-response curves of MEP amplitudes were fit with a four-parameter sigmoidal curve and the maximal slope calculated (slope max ). Habitual PA was assessed with tri-axial accelerometry and participants categorized into either those meeting the recommended PA guidelines for optimal health benefits (>10,000 steps/day, high-PA; n = 21) or those not meeting the guidelines ( 0.05), suggesting that habitual PA influenced the excitability of the corticospinal tract projecting to the lower limb similarly in both young and old adults. These findings provide evidence that achieving the recommended PA guidelines for optimal health may mediate its effects on the nervous system by decreasing corticospinal excitability. NEW & NOTEWORTHY Transcranial magnetic stimulation was used to determine whether achieving the recommended 10,000 steps/day for optimal health influenced the excitability of the corticospinal tract projecting to the knee extensor muscles. Irrespective of age and sex, individuals who achieved >10,000 steps/day had lower corticospinal excitability than those who performed Physical activity involving >10,000 steps/day may mediate its effects on the nervous system by decreasing

  11. Interaction of the modulated electron beam with inhomogeneous plasma: plasma density profile deformation and langmuir waves excitation

    International Nuclear Information System (INIS)

    Anisimov, I.O.; Kelnyk, O.I.; Soroka, S.V.; Siversky, T.V.

    2005-01-01

    Nonlinear deformation of the initially linear plasma density profile due to the modulated electron beam is studied via computer simulation. In the initial time period the field slaves to the instantaneous profile of the plasma density. Langmuir waves excitation is suppressed by the density profile deformation. The character of the plasma density profile deformation for the late time period depends significantly on the plasma properties. Particularly, for plasma with hot electrons quasi-periodic generation of ion-acoustic pulses takes place in the vicinity of the initial point of plasma resonance

  12. Immune and cell modulation by amino acids.

    Science.gov (United States)

    Roth, Erich

    2007-10-01

    Sir David Cuthbertson was the first to define metabolic alterations in post-aggression syndrome (PAS). From basic measurements of nitrogen loss and total protein synthesis/degradation, the current research has moved to genomics, proteomics and metabolomics. In this respect, first evidence was accumulated for the influence of acute catabolism, immobilisation by bed rest and sarcopenia of old age on the muscle-cell genome and proteome. Moreover, in post-aggression syndrome specific amino acids such as glutamine, arginine, glycine, taurine, tryptophan and cysteine are used for cell and immune modulation. Our laboratory has focused on the regulative capacity of glutamine. Glutamine deficiency as found in post-aggression syndrome reduces lymphocyte proliferation, alters monocyte/macrophage activity, decreases the formation of heat-shock proteins, stimulates cell apoptosis, shifts the cellular redox potential by altering the glutathione synthesis and increases the activity of the AMPK system. Investigating the molecular effect of glutamine on Hsp 70 induction, we tested the glutamine dependence on the formation of transfer-RNA and of heat-shock factor 1 (HSF 1), and on transcription and translation of Hsp 70. We could demonstrate that glutamine stabilises the mRNA of Hsp 70 thereby prolonging its half-life. The lecture also discusses the principal molecular targets of administered arginine, glycine, cysteine, taurine and tryptophan.

  13. Spiral ganglion cell site of excitation I: comparison of scala tympani and intrameatal electrode responses.

    Science.gov (United States)

    Cartee, Lianne A; Miller, Charles A; van den Honert, Chris

    2006-05-01

    To determine the site of excitation on the spiral ganglion cell in response to electrical stimulation similar to that from a cochlear implant, single-fiber responses to electrical stimuli delivered by an electrode positioned in the scala tympani were compared to responses from stimuli delivered by an electrode placed in the internal auditory meatus. The response to intrameatal stimulation provided a control set of data with a known excitation site, the central axon of the spiral ganglion cell. For both intrameatal and scala tympani stimuli, the responses to single-pulse, summation, and refractory stimulus protocols were recorded. The data demonstrated that summation pulses, as opposed to single pulses, are likely to give the most insightful measures for determination of the site of excitation. Single-fiber summation data for both scala tympani and intrameatally stimulated fibers were analyzed with a clustering algorithm. Combining cluster analysis and additional numerical modeling data, it was hypothesized that the scala tympani responses corresponded to central excitation, peripheral excitation adjacent to the cell body, and peripheral excitation at a site distant from the cell body. Fibers stimulated by an intrameatal electrode demonstrated the greatest range of jitter measurements indicating that greater fiber independence may be achieved with intrameatal stimulation.

  14. Remarkable solvent-dependent excited-state chirality : A molecular modulator of circularly polarized luminescence

    NARCIS (Netherlands)

    van Delden, Richard A.; Huck, N.P.M.; Piet, J.J.; Warman, J.M.; Meskers, S.C.J.; Dekkers, H.P J M; Feringa, B.L.

    2003-01-01

    The photochemical control of ground- and excited-state chirality of (M)-cis-(1) and (P)-trans(2)-2-nitro-7-(dimethylamino)-9-(2',3'-dihydro-1'H-naphtho[2,1-b]-thiopyran-1'-ylidene)-9H-thioxanthene is described. It is shown that while ground state chirality can be controlled photochemically by

  15. Remarkable solvent-dependent excited-state chirality : a molecular modulator of circularly polarized luminescence

    NARCIS (Netherlands)

    Delden, van R.A.; Huck, H.P.M.; Piet, J.J.; Warman, J.M.; Meskers, S.C.J.; Dekkers, H.P.J.M.; Feringa, B.L.

    2003-01-01

    The photochemical control of ground- and excited-state chirality of (M)-cis-(1) and (P)-trans-(2)-2-nitro-7-(dimethylamino)-9-(2',3' -dihydro-1'H-naphtho[2,1-b]-thiopyran-1'-ylidene)-9H-thioxanthene is described. It is shown that while ground state chirality can be controlled photochemically by

  16. Atypical excitation-inhibition balance in autism captured by the gamma response to contextual modulation

    NARCIS (Netherlands)

    Snijders, T.M.; Milivojevic, B.; Kemner, C.

    2013-01-01

    Atypical visual perception in people with autism spectrum disorders (ASD) is hypothesized to stem from an imbalance in excitatory and inhibitory processes in the brain. We used neuronal oscillations in the gamma frequency range (30–90 Hz), which emerge from a balanced interaction of excitation and

  17. Solar cell junction temperature measurement of PV module

    KAUST Repository

    Huang, B.J.; Yang, P.E.; Lin, Y.P.; Lin, B.Y.; Chen, H.J.; Lai, R.C.; Cheng, J.S.

    2011-01-01

    The present study develops a simple non-destructive method to measure the solar cell junction temperature of PV module. The PV module was put in the environmental chamber with precise temperature control to keep the solar PV module as well

  18. Cell Adhesions: Actin-Based Modules that Mediate Cell-Extracellular Matrix and Cell-Cell Interactions

    Science.gov (United States)

    Bachir, Alexia; Horwitz, Alan Rick; Nelson, W. James; Bianchini, Julie M.

    2018-01-01

    Cell adhesions link cells to the extracellular matrix (ECM) and to each other, and depend on interactions with the actin cytoskeleton. Both cell-ECM and cell-cell adhesion sites contain discrete, yet overlapping functional modules. These modules establish physical association with the actin cytoskeleton, locally modulate actin organization and dynamics, and trigger intracellular signaling pathways. Interplay between these modules generates distinct actin architectures that underlie different stages, types, and functions of cell-ECM and cell-cell adhesions. Actomyosin contractility is required to generate mature, stable adhesions, as well as sense and translate the mechanical properties of the cellular environment to changes in cell organization and behavior. In this chapter we discuss the organization and function of different adhesion modules and how they interact with the actin cytoskeleton. We highlight the molecular mechanisms of mechanotransduction in adhesions, and how adhesion molecules mediate crosstalk between cell-ECM and cell-cell adhesion sites. PMID:28679638

  19. Differential modulation of corticospinal excitability by different current densities of anodal transcranial direct current stimulation.

    Directory of Open Access Journals (Sweden)

    Andisheh Bastani

    Full Text Available BACKGROUND: Novel non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS have been developed in recent years. TDCS-induced corticospinal excitability changes depend on two important factors current intensity and stimulation duration. Despite clinical success with existing tDCS parameters, optimal protocols are still not entirely set. OBJECTIVE/HYPOTHESIS: The current study aimed to investigate the effects of four different anodal tDCS (a-tDCS current densities on corticospinal excitability. METHODS: Four current intensities of 0.3, 0.7, 1.4 and 2 mA resulting in current densities (CDs of 0.013, 0.029, 0.058 and 0.083 mA/cm(2 were applied on twelve right-handed (mean age 34.5±10.32 yrs healthy individuals in different sessions at least 48 hours apart. a-tDCS was applied continuously for 10 minute, with constant active and reference electrode sizes of 24 and 35 cm(2 respectively. The corticospinal excitability of the extensor carpi radialis muscle (ECR was measured before and immediately after the intervention and at 10, 20 and 30 minutes thereafter. RESULTS: Post hoc comparisons showed significant differences in corticospinal excitability changes for CDs of 0.013 mA/cm(2 and 0.029 mA/cm(2 (P = 0.003. There were no significant differences between excitability changes for the 0.013 mA/cm(2 and 0.058 mA/cm(2 (P = 0.080 or 0.013 mA/cm(2 and 0.083 mA/cm(2 (P = 0.484 conditions. CONCLUSION: This study found that a-tDCS with a current density of 0.013 mA/cm(2 induces significantly larger corticospinal excitability changes than CDs of 0.029 mA/cm(2. The implication is that might help to avoid applying unwanted amount of current to the cortical areas.

  20. Use of modulated excitation signals in ultrasound. Part II: Design and performance for medical imaging applications

    DEFF Research Database (Denmark)

    Misaridis, Thanassis; Jensen, Jørgen Arendt

    2005-01-01

    ultrasound presents design methods of linear FM signals and mismatched filters, in order to meet the higher demands on resolution in ultrasound imaging. It is shown that for the small time-bandwidth (TB) products available in ultrasound, the rectangular spectrum approximation is not valid, which reduces....... The method is evaluated first for resolution performance and axial sidelobes through simulations with the program Field II. A coded excitation ultrasound imaging system based on a commercial scanner and a 4 MHz probe driven by coded sequences is presented and used for the clinical evaluation of the coded...... excitation/compression scheme. The clinical images show a significant improvement in penetration depth and contrast, while they preserve both axial and lateral resolution. At the maximum acquisition depth of 15 cm, there is an improvement of more than 10 dB in the signal-to-noise ratio of the images...

  1. Presence and Absence of Muscle Contraction Elicited by Peripheral Nerve Electrical Stimulation Differentially Modulate Primary Motor Cortex Excitability

    Science.gov (United States)

    Sasaki, Ryoki; Kotan, Shinichi; Nakagawa, Masaki; Miyaguchi, Shota; Kojima, Sho; Saito, Kei; Inukai, Yasuto; Onishi, Hideaki

    2017-01-01

    Modulation of cortical excitability by sensory inputs is a critical component of sensorimotor integration. Sensory afferents, including muscle and joint afferents, to somatosensory cortex (S1) modulate primary motor cortex (M1) excitability, but the effects of muscle and joint afferents specifically activated by muscle contraction are unknown. We compared motor evoked potentials (MEPs) following median nerve stimulation (MNS) above and below the contraction threshold based on the persistence of M-waves. Peripheral nerve electrical stimulation (PES) conditions, including right MNS at the wrist at 110% motor threshold (MT; 110% MNS condition), right MNS at the index finger (sensory digit nerve stimulation [DNS]) with stimulus intensity approximately 110% MNS (DNS condition), and right MNS at the wrist at 90% MT (90% MNS condition) were applied. PES was administered in a 4 s ON and 6 s OFF cycle for 20 min at 30 Hz. In Experiment 1 (n = 15), MEPs were recorded from the right abductor pollicis brevis (APB) before (baseline) and after PES. In Experiment 2 (n = 15), M- and F-waves were recorded from the right APB. Stimulation at 110% MNS at the wrist evoking muscle contraction increased MEP amplitudes after PES compared with those at baseline, whereas DNS at the index finger and 90% MNS at the wrist not evoking muscle contraction decreased MEP amplitudes after PES. M- and F-waves, which reflect spinal cord or muscular and neuromuscular junctions, did not change following PES. These results suggest that muscle contraction and concomitant muscle/joint afferent inputs specifically enhance M1 excitability. PMID:28392766

  2. Laminated photovoltaic modules using back-contact solar cells

    Science.gov (United States)

    Gee, James M.; Garrett, Stephen E.; Morgan, William P.; Worobey, Walter

    1999-09-14

    Photovoltaic modules which comprise back-contact solar cells, such as back-contact crystalline silicon solar cells, positioned atop electrically conductive circuit elements affixed to a planar support so that a circuit capable of generating electric power is created. The modules are encapsulated using encapsulant materials such as EVA which are commonly used in photovoltaic module manufacture. The module designs allow multiple cells to be electrically connected in a single encapsulation step rather than by sequential soldering which characterizes the currently used commercial practices.

  3. Operating Cell Temperature Determination in Flat-Plate Photovoltaic Modules

    International Nuclear Information System (INIS)

    Chenlo, F.

    2002-01-01

    Two procedures (simplified and complete) to determine me operating cell temperature in photovoltaic modules operating in real conditions assuming isothermal stationary modules are presented in this work. Some examples are included that show me dependence of this temperature on several environmental (sky, ground and ambient temperatures, solar irradiance, wind speed, etc.) and structural (module geometry and size, encapsulating materials, anti reflexive optical coatings, etc.) factors and also on electrical module performance. In a further step temperature profiles for non-isothermal modules are analysed besides transitory effects due to variable irradiance and wind gusts. (Author) 27 refs

  4. Experimental evidences of modulational instability of Langmuir waves excited by an electron beam in a plasma

    International Nuclear Information System (INIS)

    Karfidov, D.M.; Alves, M.V.; Prado, F. do; Ueda, M.

    1993-01-01

    The results obtained in a beam plasma interaction experiment are reported. The experiment and the wave energy growth and saturation are governed by kinetic effects. The estimation of the maximum wave energy due to the warm beam quasi-linear diffusion process gives W r ≥ (κ o λ D ) 2 , indicating that the modulational instability can be the responsible mechanism for the suppression of the beam plasma instability observed in the experiment. (author)

  5. p-Type MWT. Integrated cell and module technology

    Energy Technology Data Exchange (ETDEWEB)

    Tool, C.J.J.; Kossen, E.J.; Bennett, I.J.

    2013-10-15

    A major issue of concern in MWT solar cells is the increased leakage current at reversed bias voltage through the vias compared. At ECN we have been working on reducing this leakage current to levels comparable to H-pattern cells. In this study we present the results of this work. We further show the benefit of a combined cell and module design for MWT solar cells. At the cell level, MWT production costs per wafer are comparable with H-pattern while the cell output increases. At the module level this design results in a further increase of the power output.

  6. p-type MWT. Integrated Cell and Module Technology

    Energy Technology Data Exchange (ETDEWEB)

    Tool, C.J.J.; Kossen, E.J.; Bennett, I.J. [ECN Solar Energy, Petten (Netherlands)

    2013-03-15

    A major issue of concern in MWT (metal wrap-through) solar cells is the increased leakage current at reversed bias voltage through the vias compared. At ECN we have been working on reducing this leakage current to levels comparable to H-pattern cells. In this study we present the results of this work. We further show the benefit of a combined cell and module design for MWT solar cells. At the cell level, MWT production costs per wafer are comparable with H-pattern while the cell output increases. At the module level this design results in a further increase of the power output.

  7. Formation of photovoltaic modules based on polycrystalline solar cells

    OpenAIRE

    L. A. Dobrzański; A. Drygała; A. Januszka

    2009-01-01

    Purpose: The main aim of the paper is formation of photovoltaic modules and analysis of their main electric parameters.Design/methodology/approach: Photovoltaic modules were produced from four polycrystalline silicon solar cells, that were cut and next joined in series. Soft soldering technique and copper-tin strip were used for joining cells.Findings: In order to provide useful power for any application, the individual solar cells must be connected together to give the appropriate current an...

  8. Modulation of motor cortex excitability by paired peripheral and transcranial magnetic stimulation.

    Science.gov (United States)

    Kumru, Hatice; Albu, Sergiu; Rothwell, John; Leon, Daniel; Flores, Cecilia; Opisso, Eloy; Tormos, Josep Maria; Valls-Sole, Josep

    2017-10-01

    Repetitive application of peripheral electrical stimuli paired with transcranial magnetic stimulation (rTMS) of M1 cortex at low frequency, known as paired associative stimulation (PAS), is an effective method to induce motor cortex plasticity in humans. Here we investigated the effects of repetitive peripheral magnetic stimulation (rPMS) combined with low frequency rTMS ('magnetic-PAS') on intracortical and corticospinal excitability and whether those changes were widespread or circumscribed to the cortical area controlling the stimulated muscle. Eleven healthy subjects underwent three 10min stimulation sessions: 10HzrPMS alone, applied in trains of 5 stimuli every 10s (60 trains) on the extensor carpi radialis (ECR) muscle; rTMS alone at an intensity 120% of ECR threshold, applied over motor cortex of ECR and at a frequency of 0.1Hz (60 stimuli) and magnetic PAS, i.e., paired rPMS and rTMS. We recorded motor evoked potentials (MEPs) from ECR and first dorsal interosseous (FDI) muscles. We measured resting motor threshold, motor evoked potentials (MEP) amplitude at 120% of RMT, short intracortical inhibition (SICI) at interstimulus interval (ISI) of 2ms and intracortical facilitation (ICF) at an ISI of 15ms before and immediately after each intervention. Magnetic-PAS , but not rTMS or rPMS applied separately, increased MEP amplitude and reduced short intracortical inhibition in ECR but not in FDI muscle. Magnetic-PAS can increase corticospinal excitability and reduce intracortical inhibition. The effects may be specific for the area of cortical representation of the stimulated muscle. Application of magnetic-PAS might be relevant for motor rehabilitation. Copyright © 2017 International Federation of Clinical Neurophysiology. All rights reserved.

  9. Temperature dependence of photovoltaic cells, modules, and systems

    Energy Technology Data Exchange (ETDEWEB)

    Emery, K.; Burdick, J.; Caiyem, Y. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    Photovoltaic (PV) cells and modules are often rated in terms of a set of standard reporting conditions defined by a temperature, spectral irradiance, and total irradiance. Because PV devices operates over a wide range of temperatures and irradiances, the temperature and irradiance related behavior must be known. This paper surveys the temperature dependence of crystalline and thin-film, state-of-the-art, research-size cells, modules, and systems measured by a variety of methods. The various error sources and measurement methods that contribute to cause differences in the temperature coefficient for a given cell or module measured with various methods are discussed.

  10. Simultaneous live cell imaging using dual FRET sensors with a single excitation light.

    Directory of Open Access Journals (Sweden)

    Yusuke Niino

    Full Text Available Fluorescence resonance energy transfer (FRET between fluorescent proteins is a powerful tool for visualization of signal transduction in living cells, and recently, some strategies for imaging of dual FRET pairs in a single cell have been reported. However, these necessitate alteration of excitation light between two different wavelengths to avoid the spectral overlap, resulting in sequential detection with a lag time. Thus, to follow fast signal dynamics or signal changes in highly motile cells, a single-excitation dual-FRET method should be required. Here we reported this by using four-color imaging with a single excitation light and subsequent linear unmixing to distinguish fluorescent proteins. We constructed new FRET sensors with Sapphire/RFP to combine with CFP/YFP, and accomplished simultaneous imaging of cAMP and cGMP in single cells. We confirmed that signal amplitude of our dual FRET measurement is comparable to of conventional single FRET measurement. Finally, we demonstrated to monitor both intracellular Ca(2+ and cAMP in highly motile cardiac myocytes. To cancel out artifacts caused by the movement of the cell, this method expands the applicability of the combined use of dual FRET sensors for cell samples with high motility.

  11. High pressure and [Ca2+] produce an inverse modulation of synaptic input strength, network excitability and frequency response in the rat dentate gyrus

    Directory of Open Access Journals (Sweden)

    Thomas I Talpalar

    2016-09-01

    Full Text Available Hyperbaric environments induce the high pressure neurological syndrome (HPNS characterized by hyperexcitability of the central nervous system and memory impairment. Human divers and other animals experience the HPNS at pressures beyond 1.1 MPa. High pressure depresses synaptic transmission and alters its dynamics in various animal models. Medial perforant path (MPP synapses connecting the medial entorhinal cortex with the hippocampal formation are suppressed by 50% at 10.1MPa. Reduction of synaptic inputs is paradoxically associated with enhanced ability of dentate gyrus’ granule cells to generate spikes at high pressure. This mechanism allows MPP inputs to elicit standard granule cell outputs at 0.1 -25 Hz frequencies under hyperbaric conditions. An increased postsynaptic gain of MPP inputs probably allows diving animals to perform in hyperbaric environments, but makes them vulnerable to high intensity/frequency stimuli producing hyperexcitability. Increasing extracellular Ca2+ (Ca2+o partially reverted pressure-mediated depression of MPP inputs and increased MPP’s low-pass filter properties. We postulated that raising Ca2+o in addition to increase synaptic inputs may reduce network excitability in the dentate gyrus potentially improving its function and reducing sensitivity to high intensity and pathologic stimuli. For this matter, we activated the MPP with single and 50 Hz frequency stimuli that simulated physiologic and deleterious conditions, while assessing the granule cell’s output under various conditions of pressure and Ca2+o. Our results reveal that pressure and Ca2+o produce an inverse modulation on synaptic input strength and network excitability. These coincident phenomena suggest a potential general mechanism of networks that adjusts gain as an inverse function of synaptic inputs’ strength. Such mechanism may serve for adaptation to variable pressure and other physiological and pathological conditions and may explain the

  12. Intracellular Na(+) and metabolic modulation of Na/K pump and excitability in the rat suprachiasmatic nucleus neurons.

    Science.gov (United States)

    Wang, Yi-Chi; Yang, Jyh-Jeen; Huang, Rong-Chi

    2012-10-01

    Na/K pump activity and metabolic rate are both higher during the day in the suprachiasmatic nucleus (SCN) that houses the circadian clock. Here we investigated the role of intracellular Na(+) and energy metabolism in regulating Na/K pump activity and neuronal excitability. Removal of extracellular K(+) to block the Na/K pump excited SCN neurons to fire at higher rates and return to normal K(+) to reactivate the pump produced rebound hyperpolarization to inhibit firing. In the presence of tetrodotoxin to block the action potentials, both zero K(+)-induced depolarization and rebound hyperpolarization were blocked by the cardiac glycoside strophanthidin. Ratiometric Na(+) imaging with a Na(+)-sensitive fluorescent dye indicated saturating accumulation of intracellular Na(+) in response to pump blockade with zero K(+). The Na(+) ionophore monensin also induced Na(+) loading and hyperpolarized the membrane potential, with the hyperpolarizing effect of monensin abolished in zero Na(+) or by pump blockade. Conversely, Na(+) depletion with Na(+)-free pipette solution depolarized membrane potential but retained residual Na/K pump activity. Cyanide inhibition of oxidative phosphorylation blocked the Na/K pump to depolarize resting potential and increase spontaneous firing in most cells, and to raise intracellular Na(+) levels in all cells. Nonetheless, the Na/K pump was incompletely blocked by cyanide but completely blocked by iodoacetate to inhibit glycolysis, indicating the involvement of both oxidative phosphorylation and glycolysis in fueling the Na/K pump. Together, the results indicate the importance of intracellular Na(+) and energy metabolism in regulating Na/K pump activity as well as neuronal excitability in the SCN neurons.

  13. Comparison of GSM Modulated and CW Radiofrequency Radiation on Cells

    International Nuclear Information System (INIS)

    Pavicic, I.; Marjanovic, A.M.; Trosic, I.

    2011-01-01

    The aim of our study was to evaluate and compare effect of global system of mobile (GSM) modulation and continuous wave (CW) radiofrequency radiation (RF) on proliferation ability and viability of V79 Chinese hamster lung cells. Previously prepared samples of cells in culture were exposed for 1, 2 and 3 hours both to 915 MHz GSM modulated and to 935 MHz CW RF field in gigahertz transversal electromagnetic mode cell (GTEM-cell). Electric field strength for cells exposed to GSM modulation was set at 10 V/m and for CW exposed cells was 8.2 V/m. Average specific absorption rate (SAR) was calculated to be for GSM 0.23 W/kg and for CW 0.12 W/kg. V79 samples were plated in concentration of 1x10 4 cells/mL. Cell proliferation was determined by cell counts for each hour of exposure during five post-exposure days. Trypan blue exclusion test was used to determine cell viability. In comparison to control cell samples, proliferation of GSM irradiated cells showed significant decrease after 3 hours of exposure on the second and third post-exposure day. CW exposed cell samples showed significant decrease after 3 hours of exposure on the third post-exposure day. Viability of GSM and CW exposed cells did not significantly differ from matched control cell samples. Both applied RF fields have shown similar effect on cell culture growth, and cell viability of V79 cell line. In addition, applied GSM modulated RF radiation demonstrate bigger influence on proliferation of cells. (author)

  14. Plant Cell Imaging Based on Nanodiamonds with Excitation-Dependent Fluorescence

    Science.gov (United States)

    Su, Li-Xia; Lou, Qing; Jiao, Zhen; Shan, Chong-Xin

    2016-09-01

    Despite extensive work on fluorescence behavior stemming from color centers of diamond, reports on the excitation-dependent fluorescence of nanodiamonds (NDs) with a large-scale redshift from 400 to 620 nm under different excitation wavelengths are so far much fewer, especially in biological applications. The fluorescence can be attributed to the combined effects of the fraction of sp2-hybridized carbon atoms among the surface of the fine diamond nanoparticles and the defect energy trapping states on the surface of the diamond. The excitation-dependent fluorescent NDs have been applied in plant cell imaging for the first time. The results reported in this paper may provide a promising route to multiple-color bioimaging using NDs.

  15. Plant Cell Imaging Based on Nanodiamonds with Excitation-Dependent Fluorescence.

    Science.gov (United States)

    Su, Li-Xia; Lou, Qing; Jiao, Zhen; Shan, Chong-Xin

    2016-12-01

    Despite extensive work on fluorescence behavior stemming from color centers of diamond, reports on the excitation-dependent fluorescence of nanodiamonds (NDs) with a large-scale redshift from 400 to 620 nm under different excitation wavelengths are so far much fewer, especially in biological applications. The fluorescence can be attributed to the combined effects of the fraction of sp(2)-hybridized carbon atoms among the surface of the fine diamond nanoparticles and the defect energy trapping states on the surface of the diamond. The excitation-dependent fluorescent NDs have been applied in plant cell imaging for the first time. The results reported in this paper may provide a promising route to multiple-color bioimaging using NDs.

  16. Neurosteroid modulation of neuronal excitability and synaptic transmission in the rat medial vestibular nuclei.

    Science.gov (United States)

    Grassi, Silvarosa; Frondaroli, Adele; Dieni, Cristina; Dutia, Mayank B; Pettorossi, Vito E

    2007-07-01

    In rat brainstem slices, we investigated the influence of the neurosteroids tetrahydrodeoxycorticosterone (THDOC) and allopregnanolone (ALLO) on the synaptically driven and spontaneous activity of vestibular neurons, by analysing their effects on the amplitude of the field potentials evoked in the medial vestibular nuclei (MVN) by vestibular afferent stimulation and on the spontaneous firing rate of MVN neurons. Furthermore, the interaction with gamma-aminobutyric acid (GABA) and glutamate receptors was analysed by using specific antagonists for GABA(A) (bicuculline), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/ kainate [2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo(f)quinoxaline-7-sulphonamide disodium salt (NBQX)], N-methyl-D-aspartate (NMDA) [D-(-)-2-amino-5-phosphonopentanoic acid (AP-5)] and group I metabotropic glutamate receptors (mGlu-I) [(R,S)-1-aminoindan-1,5-dicarboxylic acid (AIDA)] receptors. THDOC and ALLO evoked two opposite long-lasting effects, consisting of either a potentiation or a reduction of field potential and firing rate, which showed early and late components, occurring in conjunction or separately after neurosteroid application. The depressions depended on GABA(A) receptors, as they were abolished by bicuculline, while early potentiation involved glutamate AMPA/kainate receptors, as NBQX markedly reduced the incidence of early firing rate enhancement and, in the case of ALLO, even provoked depression. This suggests that THDOC and ALLO enhance the GABA(A) inhibitory influence on the MVN neurons and facilitate the AMPA/kainate facilitatory one. Conversely, a late potentiation effect, which was still induced after glutamate and GABA(A) receptor blockade, might involve a different mechanism. We conclude that the modulation of neuronal activity in the MVN by THDOC and ALLO, through their actions on GABA(A) and AMPA/kainate receptors, may have a physiological role in regulating the vestibular system function under normal

  17. Circuit analysis method for thin-film solar cell modules

    Science.gov (United States)

    Burger, D. R.

    1985-01-01

    The design of a thin-film solar cell module is dependent on the probability of occurrence of pinhole shunt defects. Using known or assumed defect density data, dichotomous population statistics can be used to calculate the number of defects expected in a module. Probability theory is then used to assign the defective cells to individual strings in a selected series-parallel circuit design. Iterative numerical calculation is used to calcuate I-V curves using cell test values or assumed defective cell values as inputs. Good and shunted cell I-V curves are added to determine the module output power and I-V curve. Different levels of shunt resistance can be selected to model different defect levels.

  18. Changes in intrinsic excitability of ganglion cells in degenerated retinas of RCS rats

    Directory of Open Access Journals (Sweden)

    Yi-Ming Ren

    2018-05-01

    Full Text Available AIM: To evaluate the intrinsic excitability of retinal ganglion cells (RGCs in degenerated retinas. METHODS: The intrinsic excitability of various morphologically defined RGC types using a combination of patch-clamp recording and the Lucifer yellow tracer in retinal whole-mount preparations harvested from Royal College of Surgeons (RCS rats, a common retinitis pigmentosa (RP model, in a relatively late stage of retinal degeneration (P90 were investigated. Several parameters of RGC morphologies and action potentials (APs were measured and compared to those of non-dystrophic control rats, including dendritic stratification, dendritic field diameter, peak amplitude, half width, resting membrane potential, AP threshold, depolarization to threshold, and firing rates. RESULTS: Compared with non-dystrophic control RGCs, more depolarizations were required to reach the AP threshold in RCS RGCs with low spontaneous spike rates and in RCS OFF cells (especially A2o cells, and RCS RGCs maintained their dendritic morphologies, resting membrane potentials and capabilities to generate APs. CONCLUSION: RGCs are relatively well preserved morphologically and functionally, and some cells are more susceptible to decreased excitability during retinal degeneration. These findings provide valuable considerations for optimizing RP therapeutic strategies.

  19. β-Adrenergic modulation of skeletal muscle contraction: key role of excitation-contraction coupling.

    Science.gov (United States)

    Cairns, Simeon P; Borrani, Fabio

    2015-11-01

    Our aim is to describe the acute effects of catecholamines/β-adrenergic agonists on contraction of non-fatigued skeletal muscle in animals and humans, and explain the mechanisms involved. Adrenaline/β-agonists (0.1-30 μm) generally augment peak force across animal species (positive inotropic effect) and abbreviate relaxation of slow-twitch muscles (positive lusitropic effect). A peak force reduction also occurs in slow-twitch muscles in some conditions. β2 -Adrenoceptor stimulation activates distinct cyclic AMP-dependent protein kinases to phosphorylate multiple target proteins. β-Agonists modulate sarcolemmal processes (increased resting membrane potential and action potential amplitude) via enhanced Na(+) -K(+) pump and Na(+) -K(+) -2Cl(-) cotransporter function, but this does not increase force. Myofibrillar Ca(2+) sensitivity and maximum Ca(2+) -activated force are unchanged. All force potentiation involves amplified myoplasmic Ca(2+) transients consequent to increased Ca(2+) release from sarcoplasmic reticulum (SR). This unequivocally requires phosphorylation of SR Ca(2+) release channels/ryanodine receptors (RyR1) which sensitize the Ca(2+) -induced Ca(2+) release mechanism. Enhanced trans-sarcolemmal Ca(2+) influx through phosphorylated voltage-activated Ca(2+) channels contributes to force potentiation in diaphragm and amphibian muscle, but not mammalian limb muscle. Phosphorylation of phospholamban increases SR Ca(2+) pump activity in slow-twitch fibres but does not augment force; this process accelerates relaxation and may depress force. Greater Ca(2+) loading of SR may assist force potentiation in fast-twitch muscle. Some human studies show no significant force potentiation which appears to be related to the β-agonist concentration used. Indeed high-dose β-agonists (∼0.1 μm) enhance SR Ca(2+) -release rates, maximum voluntary contraction strength and peak Wingate power in trained humans. The combined findings can explain how adrenaline

  20. Two-photon excited autofluorescence imaging of human retinal pigment epithelial cells

    Science.gov (United States)

    Han, Meng; Blindewald-Wittich, Almut; Holz, Frank G.; Giese, Günter; Niemz, Markolf H.; Snyder, Sarah; Sun, Hui; Yu, Jiayi; Agopov, Michael; La Schiazza, Olivier; Bille, Josef F.

    2006-01-01

    Degeneration of retinal pigment epithelial (RPE) cells severely impairs the visual function of retina photoreceptors. However, little is known about the events that trigger the death of RPE cells at the subcellular level. Two-photon excited autofluorescence (TPEF) imaging of RPE cells proves to be well suited to investigate both the morphological and the spectral characteristics of the human RPE cells. The dominant fluorophores of autofluorescence derive from lipofuscin (LF) granules that accumulate in the cytoplasm of the RPE cells with increasing age. Spectral TPEF imaging reveals the existence of abnormal LF granules with blue shifted autofluorescence in RPE cells of aging patients and brings new insights into the complicated composition of the LF granules. Based on a proposed two-photon laser scanning ophthalmoscope, TPEF imaging of the living retina may be valuable for diagnostic and pathological studies of age related eye diseases.

  1. The mechanism of abrupt transition between theta and hyper-excitable spiking activity in medial entorhinal cortex layer II stellate cells.

    Directory of Open Access Journals (Sweden)

    Tilman Kispersky

    2010-11-01

    Full Text Available Recent studies have shown that stellate cells (SCs of the medial entorhinal cortex become hyper-excitable in animal models of temporal lobe epilepsy. These studies have also demonstrated the existence of recurrent connections among SCs, reduced levels of recurrent inhibition in epileptic networks as compared to control ones, and comparable levels of recurrent excitation among SCs in both network types. In this work, we investigate the biophysical and dynamic mechanism of generation of the fast time scale corresponding to hyper-excitable firing and the transition between theta and fast firing frequency activity in SCs. We show that recurrently connected minimal networks of SCs exhibit abrupt, threshold-like transition between theta and hyper-excitable firing frequencies as the result of small changes in the maximal synaptic (AMPAergic conductance. The threshold required for this transition is modulated by synaptic inhibition. Similar abrupt transition between firing frequency regimes can be observed in single, self-coupled SCs, which represent a network of recurrently coupled neurons synchronized in phase, but not in synaptically isolated SCs as the result of changes in the levels of the tonic drive. Using dynamical systems tools (phase-space analysis, we explain the dynamic mechanism underlying the genesis of the fast time scale and the abrupt transition between firing frequency regimes, their dependence on the intrinsic SC's currents and synaptic excitation. This abrupt transition is mechanistically different from others observed in similar networks with different cell types. Most notably, there is no bistability involved. 'In vitro' experiments using single SCs self-coupled with dynamic clamp show the abrupt transition between firing frequency regimes, and demonstrate that our theoretical predictions are not an artifact of the model. In addition, these experiments show that high-frequency firing is burst-like with a duration modulated by an M-current.

  2. Applications of ``PV Optics`` for solar cell and module design

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B.L.; Madjdpour, J.; Chen, W. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    This paper describes some applications of a new optics software package, PV Optics, developed for the optical design of solar cells and modules. PV Optics is suitable for the analysis and design of both thick and thin solar cells. It also includes a feature for calculation of metallic losses related to contacts and back reflectors.

  3. Convergence of Ground and Excited State Properties of Divacancy Defects in 4H-SiC with Computational Cell Size

    Science.gov (United States)

    2018-03-01

    SiC with Computational Cell Size by Ariana Beste and DeCarlos E Taylor Approved for public release; distribution is unlimited...Laboratory Convergence of Ground and Excited State Properties of Divacancy Defects in 4H-SiC with Computational Cell Size by Ariana Beste...Ground and Excited State Properties of Divacancy Defects in 4H-SiC with Computational Cell Size 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM

  4. Transparent electrode requirements for thin film solar cell modules

    KAUST Repository

    Rowell, Michael W.; McGehee, Michael D.

    2011-01-01

    The transparent conductor (TC) layer in thin film solar cell modules has a significant impact on the power conversion efficiency. Reflection, absorption, resistive losses and lost active area either from the scribed interconnect region in monolithically integrated modules or from the shadow losses of a metal grid in standard modules typically reduce the efficiency by 10-25%. Here, we perform calculations to show that a competitive TC must have a transparency of at least 90% at a sheet resistance of less than 10 Ω/sq (conductivity/absorptivity ≥ 1 Ω -1) for monolithically integrated modules. For standard modules, losses are much lower and the performance of alternative lower cost TC materials may already be sufficient to replace conducting oxides in this geometry. © 2011 The Royal Society of Chemistry.

  5. APRIL modulates B and T cell immunity

    NARCIS (Netherlands)

    Stein, Jens V.; López-Fraga, Marta; Elustondo, Fernando A.; Carvalho-Pinto, Carla E.; Rodríguez, Dolores; Gómez-Caro, Ruth; de Jong, Joan; Martínez-A, Carlos; Medema, Jan Paul; Hahne, Michael

    2002-01-01

    The TNF-like ligands APRIL and BLyS are close relatives and share the capacity to bind the receptors TACI and BCMA. BLyS has been shown to play an important role in B cell homeostasis and autoimmunity, but the biological role of APRIL remains less well defined. Analysis of T cells revealed an

  6. A targeting drug-delivery model via interactions among cells and liposomes under ultrasonic excitation

    International Nuclear Information System (INIS)

    Xi Xiaoyu; Zhang Dong; Yang Fang; Gu Ning; Chen Di; Wu Junru; Luo Yi

    2008-01-01

    In our previous work, it was found that acoustic cavitation might play a role in improving the cell permeability to microparticles when liposomes were used in an in vitro experiment. The purpose of this project is to expand our study and to learn other possible mechanisms by which cells may interact with liposomes under ultrasound (US) excitation and become transiently permeable to microparticles. It is further hypothesized that two possible scenarios may be involved in in vitro experiments: (1) drug-carrying liposomes transiently overcome the cell membrane barrier and enter into a cell while the cell is still viable; (2) the liposomes incorporate with a cell at its membrane through a fusing process. To prove this hypothesis, liposomes of two different structures were synthesized: one has fluorescent molecules encapsulated into liposomes and the other has fluorescent markers incorporated into the shells of liposomes. Liposomes of each kind were mixed with human breast cancer cells (MCF7-cell line) in a suspension at 5 (liposomes) : 1 (cell) ratio and were then exposed to a focused 1 MHz ultrasound beam at its focal region for 40 s. The US signal contained 20 cycles per tone-burst at a pulse-repetition-frequency of 10 kHz; the spatial peak acoustic pressure amplitude was 0.25 MPa. It was found that the possible mechanisms might include the acoustic cavitation, the endocytosis and cell-fusion. Acoustic radiation force might make liposomes collide with cells effectively and facilitate the delivery process

  7. High frequency time modulation of neutrons by LiNbO3 crystals with surface acoustic waves excited under the diffraction condition

    International Nuclear Information System (INIS)

    Takahashi, Toshio; Granzer, E.; Kikuta, Seishi; Tomimitsu, Hiroshi; Doi, Kenji.

    1985-01-01

    High frequency time modulation of neutrons was investigated by using Y-cut LiNbO 3 crystals with surface acoustic waves excited. A double crystal arrangement of (+, -) parallel setting was used for 030 symmetric Bragg-case reflections. Synchronized standing waves with a resonance frequency of 14.26 MHz were excited on the both crystals. Variation of the diffracted intensity with phase difference between two standing waves was studied. The result showed an intensity change of diffracted neutrons with twice the resonance frequency. (author)

  8. Dual photon excitation microscopy and image threshold segmentation in live cell imaging during compression testing.

    Science.gov (United States)

    Moo, Eng Kuan; Abusara, Ziad; Abu Osman, Noor Azuan; Pingguan-Murphy, Belinda; Herzog, Walter

    2013-08-09

    Morphological studies of live connective tissue cells are imperative to helping understand cellular responses to mechanical stimuli. However, photobleaching is a constant problem to accurate and reliable live cell fluorescent imaging, and various image thresholding methods have been adopted to account for photobleaching effects. Previous studies showed that dual photon excitation (DPE) techniques are superior over conventional one photon excitation (OPE) confocal techniques in minimizing photobleaching. In this study, we investigated the effects of photobleaching resulting from OPE and DPE on morphology of in situ articular cartilage chondrocytes across repeat laser exposures. Additionally, we compared the effectiveness of three commonly-used image thresholding methods in accounting for photobleaching effects, with and without tissue loading through compression. In general, photobleaching leads to an apparent volume reduction for subsequent image scans. Performing seven consecutive scans of chondrocytes in unloaded cartilage, we found that the apparent cell volume loss caused by DPE microscopy is much smaller than that observed using OPE microscopy. Applying scan-specific image thresholds did not prevent the photobleaching-induced volume loss, and volume reductions were non-uniform over the seven repeat scans. During cartilage loading through compression, cell fluorescence increased and, depending on the thresholding method used, led to different volume changes. Therefore, different conclusions on cell volume changes may be drawn during tissue compression, depending on the image thresholding methods used. In conclusion, our findings confirm that photobleaching directly affects cell morphology measurements, and that DPE causes less photobleaching artifacts than OPE for uncompressed cells. When cells are compressed during tissue loading, a complicated interplay between photobleaching effects and compression-induced fluorescence increase may lead to interpretations in

  9. Influence of modulation frequency in rubidium cell frequency standards

    Science.gov (United States)

    Audoin, C.; Viennet, J.; Cyr, N.; Vanier, J.

    1983-01-01

    The error signal which is used to control the frequency of the quartz crystal oscillator of a passive rubidium cell frequency standard is considered. The value of the slope of this signal, for an interrogation frequency close to the atomic transition frequency is calculated and measured for various phase (or frequency) modulation waveforms, and for several values of the modulation frequency. A theoretical analysis is made using a model which applies to a system in which the optical pumping rate, the relaxation rates and the RF field are homogeneous. Results are given for sine-wave phase modulation, square-wave frequency modulation and square-wave phase modulation. The influence of the modulation frequency on the slope of the error signal is specified. It is shown that the modulation frequency can be chosen as large as twice the non-saturated full-width at half-maximum without a drastic loss of the sensitivity to an offset of the interrogation frequency from center line, provided that the power saturation factor and the amplitude of modulation are properly adjusted.

  10. Modulation of hepatic stellate cells and reversibility of hepatic fibrosis

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yu, E-mail: 1293363632@QQ.com [Faculty of Graduate Studies of Guangxi University of Chinese Medicine, Nanning 530001, Guangxi Zhuang Autonomous Region (China); Deng, Xin, E-mail: Hendly@163.com [Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, 10 East China Road, Nanning 530011, Guangxi Zhuang Autonomous Region (China); Liang, Jian, E-mail: lj99669@163.com [Guangxi University of Chinese Medicine, Nanning 530001, Guangxi Zhuang Autonomous Region (China)

    2017-03-15

    Hepatic fibrosis (HF) is the pathological component of a variety of chronic liver diseases. Hepatic stellate cells (HSC) are the main collagen-producing cells in the liver and their activation promotes HF. If HSC activation and proliferation can be inhibited, HF occurrence and development can theoretically be reduced and even reversed. Over the past ten years, a number of studies have addressed this process, and here we present a review of HSC modulation and HF reversal. - Highlights: • We present a review of the modulation of hepatic stellate cells (HSC) and reversibility of hepatic fibrosis (HF). • HSC are the foci of HF occurrence and development, HF could be prevented and treated by modulating HSC. • If HSC activation and proliferation can be inhibited, HF could theoretically be inhibited and even reversed. • Prevention or reversal of HSC activation, or promotion of HSC apoptosis, immune elimination, and senescence may prevent, inhibit or reverse HF.

  11. Parallel excitation-emission multiplexed fluorescence lifetime confocal microscopy for live cell imaging.

    Science.gov (United States)

    Zhao, Ming; Li, Yu; Peng, Leilei

    2014-05-05

    We present a novel excitation-emission multiplexed fluorescence lifetime microscopy (FLIM) method that surpasses current FLIM techniques in multiplexing capability. The method employs Fourier multiplexing to simultaneously acquire confocal fluorescence lifetime images of multiple excitation wavelength and emission color combinations at 44,000 pixels/sec. The system is built with low-cost CW laser sources and standard PMTs with versatile spectral configuration, which can be implemented as an add-on to commercial confocal microscopes. The Fourier lifetime confocal method allows fast multiplexed FLIM imaging, which makes it possible to monitor multiple biological processes in live cells. The low cost and compatibility with commercial systems could also make multiplexed FLIM more accessible to biological research community.

  12. Nanomaterials modulate stem cell differentiation: biological interaction and underlying mechanisms.

    Science.gov (United States)

    Wei, Min; Li, Song; Le, Weidong

    2017-10-25

    Stem cells are unspecialized cells that have the potential for self-renewal and differentiation into more specialized cell types. The chemical and physical properties of surrounding microenvironment contribute to the growth and differentiation of stem cells and consequently play crucial roles in the regulation of stem cells' fate. Nanomaterials hold great promise in biological and biomedical fields owing to their unique properties, such as controllable particle size, facile synthesis, large surface-to-volume ratio, tunable surface chemistry, and biocompatibility. Over the recent years, accumulating evidence has shown that nanomaterials can facilitate stem cell proliferation and differentiation, and great effort is undertaken to explore their possible modulating manners and mechanisms on stem cell differentiation. In present review, we summarize recent progress in the regulating potential of various nanomaterials on stem cell differentiation and discuss the possible cell uptake, biological interaction and underlying mechanisms.

  13. Cell oxidation-reduction imbalance after modulated radiofrequency radiation.

    Science.gov (United States)

    Marjanovic, Ana Marija; Pavicic, Ivan; Trosic, Ivancica

    2015-01-01

    Aim of this study was to evaluate an influence of modulated radiofrequency field (RF) of 1800 MHz, strength of 30 V/m on oxidation-reduction processes within the cell. The assigned RF field was generated within Gigahertz Transversal Electromagnetic Mode cell equipped by signal generator, modulator, and amplifier. Cell line V79, was irradiated for 10, 30, and 60 min, specific absorption rate was calculated to be 1.6 W/kg. Cell metabolic activity and viability was determined by MTT assay. In order to define total protein content, colorimetric method was used. Concentration of oxidised proteins was evaluated by enzyme-linked immunosorbent assay. Reactive oxygen species (ROS) marked with fluorescent probe 2',7'-dichlorofluorescin diacetate were measured by means of plate reader device. In comparison with control cell samples, metabolic activity and total protein content in exposed cells did not differ significantly. Concentrations of carbonyl derivates, a product of protein oxidation, insignificantly but continuously increase with duration of exposure. In exposed samples, ROS level significantly (p < 0.05) increased after 10 min of exposure. Decrease in ROS level was observed after 30-min treatment indicating antioxidant defence mechanism activation. In conclusion, under the given laboratory conditions, modulated RF radiation might cause impairment in cell oxidation-reduction equilibrium within the growing cells.

  14. Right hemisphere dominance directly predicts both baseline V1 cortical excitability and the degree of top-down modulation exerted over low-level brain structures.

    Science.gov (United States)

    Arshad, Q; Siddiqui, S; Ramachandran, S; Goga, U; Bonsu, A; Patel, M; Roberts, R E; Nigmatullina, Y; Malhotra, P; Bronstein, A M

    2015-12-17

    Right hemisphere dominance for visuo-spatial attention is characteristically observed in most right-handed individuals. This dominance has been attributed to both an anatomically larger right fronto-parietal network and the existence of asymmetric parietal interhemispheric connections. Previously it has been demonstrated that interhemispheric conflict, which induces left hemisphere inhibition, results in the modulation of both (i) the excitability of the early visual cortex (V1) and (ii) the brainstem-mediated vestibular-ocular reflex (VOR) via top-down control mechanisms. However to date, it remains unknown whether the degree of an individual's right hemisphere dominance for visuospatial function can influence, (i) the baseline excitability of the visual cortex and (ii) the extent to which the right hemisphere can exert top-down modulation. We directly tested this by correlating line bisection error (or pseudoneglect), taken as a measure of right hemisphere dominance, with both (i) visual cortical excitability measured using phosphene perception elicited via single-pulse occipital trans-cranial magnetic stimulation (TMS) and (ii) the degree of trans-cranial direct current stimulation (tDCS)-mediated VOR suppression, following left hemisphere inhibition. We found that those individuals with greater right hemisphere dominance had a less excitable early visual cortex at baseline and demonstrated a greater degree of vestibular nystagmus suppression following left hemisphere cathodal tDCS. To conclude, our results provide the first demonstration that individual differences in right hemisphere dominance can directly predict both the baseline excitability of low-level brain structures and the degree of top-down modulation exerted over them. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Solar cell junction temperature measurement of PV module

    KAUST Repository

    Huang, B.J.

    2011-02-01

    The present study develops a simple non-destructive method to measure the solar cell junction temperature of PV module. The PV module was put in the environmental chamber with precise temperature control to keep the solar PV module as well as the cell junction in thermal equilibrium with the chamber. The open-circuit voltage of PV module Voc is then measured using a short pulse of solar irradiation provided by a solar simulator. Repeating the measurements at different environment temperature (40-80°C) and solar irradiation S (200-1000W/m2), the correlation between the open-circuit voltage Voc, the junction temperature Tj, and solar irradiation S is derived.The fundamental correlation of the PV module is utilized for on-site monitoring of solar cell junction temperature using the measured Voc and S at a short time instant with open circuit. The junction temperature Tj is then determined using the measured S and Voc through the fundamental correlation. The outdoor test results show that the junction temperature measured using the present method, Tjo, is more accurate. The maximum error using the average surface temperature Tave as the junction temperature is 4.8 °C underestimation; while the maximum error using the present method is 1.3 °C underestimation. © 2010 Elsevier Ltd.

  16. Quantifying Solar Cell Cracks in Photovoltaic Modules by Electroluminescence Imaging

    DEFF Research Database (Denmark)

    Spataru, Sergiu; Hacke, Peter; Sera, Dezso

    2015-01-01

    This article proposes a method for quantifying the percentage of partially and totally disconnected solar cell cracks by analyzing electroluminescence images of the photovoltaic module taken under high- and low-current forward bias. The method is based on the analysis of the module’s electrolumin...

  17. Modulation of collective cell behaviour by geometrical constraints

    Czech Academy of Sciences Publication Activity Database

    Lunova, M.; Zablotskyy, Vitaliy A.; Dempsey, N.M.; Devillers, T.; Jirsa, M.; Syková, E.; Kubinová, Šárka; Lunov, Oleg; Dejneka, Alexandr

    2016-01-01

    Roč. 8, č. 11 (2016), s. 1099-1110 ISSN 1757-9694 Grant - others:AV ČR(CZ) Fellowship J. E. Purkyně Institutional support: RVO:68378271 Keywords : modulation * collective cell * geometrical constraints Subject RIV: BO - Biophysics Impact factor: 3.252, year: 2016

  18. Changes in the Excitability of Neocortical Neurons in a Mouse Model of Amyotrophic Lateral Sclerosis Are Not Specific to Corticospinal Neurons and Are Modulated by Advancing Disease.

    Science.gov (United States)

    Kim, Juhyun; Hughes, Ethan G; Shetty, Ashwin S; Arlotta, Paola; Goff, Loyal A; Bergles, Dwight E; Brown, Solange P

    2017-09-13

    Cell type-specific changes in neuronal excitability have been proposed to contribute to the selective degeneration of corticospinal neurons in amyotrophic lateral sclerosis (ALS) and to neocortical hyperexcitability, a prominent feature of both inherited and sporadic variants of the disease, but the mechanisms underlying selective loss of specific cell types in ALS are not known. We analyzed the physiological properties of distinct classes of cortical neurons in the motor cortex of hSOD1 G93A mice of both sexes and found that they all exhibit increases in intrinsic excitability that depend on disease stage. Targeted recordings and in vivo calcium imaging further revealed that neurons adapt their functional properties to normalize cortical excitability as the disease progresses. Although different neuron classes all exhibited increases in intrinsic excitability, transcriptional profiling indicated that the molecular mechanisms underlying these changes are cell type specific. The increases in excitability in both excitatory and inhibitory cortical neurons show that selective dysfunction of neuronal cell types cannot account for the specific vulnerability of corticospinal motor neurons in ALS. Furthermore, the stage-dependent alterations in neuronal function highlight the ability of cortical circuits to adapt as disease progresses. These findings show that both disease stage and cell type must be considered when developing therapeutic strategies for treating ALS. SIGNIFICANCE STATEMENT It is not known why certain classes of neurons preferentially die in different neurodegenerative diseases. It has been proposed that the enhanced excitability of affected neurons is a major contributor to their selective loss. We show using a mouse model of amyotrophic lateral sclerosis (ALS), a disease in which corticospinal neurons exhibit selective vulnerability, that changes in excitability are not restricted to this neuronal class and that excitability does not increase

  19. Electromagnetic Cell Level Calibration for ATLAS Tile Calorimeter Modules

    CERN Document Server

    Kulchitskii, Yu A; Budagov, Yu A; Khubua, J I; Rusakovitch, N A; Vinogradov, V B; Henriques, A; Davidek, T; Tokar, S; Solodkov, A; Vichou, I

    2006-01-01

    We have determined the electromagnetic calibration constants of 11% TileCal modules exposed to electron beams with incident angles of 20 and 90 degrees. The gain of all the calorimeter cells have been pre-equalized using the radioactive Cs-source that will be also used in situ. The average values for these modules are equal to: for the flat filter method 1.154+/-0.002 pC/GeV and 1.192+/-0.002 pC/GeV for 20 and 90 degrees, for the fit method 1.040+/-0.002 pC/GeV and 1.068+/-0.003 pC/GeV, respectively. These average values for all cells of calibrated modules agree with the weighted average calibration constants for separate modules within the errors. Using the individual calibration constants for every module the RMS spread value of constants will be 1.9+/-0.1 %. In the case of the global constant this value will be 2.6+/-0.1 %. Finally, we present the global constants which should be used for the electromagnetic calibration of the ATLAS Tile hadronic calorimeter data in the ATHENA framework. These constants ar...

  20. Performance of Photovoltaic Modules of Different Solar Cells

    Directory of Open Access Journals (Sweden)

    Ankita Gaur

    2013-01-01

    Full Text Available In this paper, an attempt of performance evaluation of semitransparent and opaque photovoltaic (PV modules of different generation solar cells, having the maximum efficiencies reported in the literature at standard test conditions (STC, has been carried out particularly for the months of January and June. The outdoor performance is also evaluated for the commercially available semitransparent and opaque PV modules. Annual electrical energy, capitalized cost, annualized uniform cost (unacost, and cost per unit electrical energy for both types of solar modules, namely, semitransparent and opaque have also been computed along with their characteristics curves. Semitransparent PV modules have shown higher efficiencies compared to the opaque ones. Calculations show that for the PV modules made in laboratory, CdTe exhibits the maximum annual electrical energy generation resulting into minimum cost per unit electrical energy, whereas a-Si/nc-Si possesses the maximum annual electrical energy generation giving minimum cost per unit electrical energy when commercially available solar modules are concerned. CIGS has shown the lowest capitalized cost over all other PV technologies.

  1. 77 FR 25400 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Science.gov (United States)

    2012-04-30

    ... Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's Republic of China: Alignment of... crystalline silicon photovoltaic cells, whether or not assembled into modules (solar cells) from the People's... Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's Republic of China: Initiation of...

  2. A photosynthetic-plasmonic-voltaic cell: Excitation of photosynthetic bacteria and current collection through a plasmonic substrate

    International Nuclear Information System (INIS)

    Samsonoff, Nathan; Ooms, Matthew D.; Sinton, David

    2014-01-01

    Excitation of photosynthetic biofilms using surface-confined evanescent light fields enables energy dense photobioreactors, while electrode-adhered biofilms can provide electricity directly. Here, we demonstrate concurrent light delivery and electron transport through a plasmonically excited metal film. Biofilms of cyanobacterium Synechococcus bacillaris on 50-nm gold films are excited via the Kretschmann configuration at λ = 670 nm. Cells show light/dark response to plasmonic excitation and grow denser biofilms, closer to the electrode surface, as compared to the direct irradiated case. Directly irradiated biofilms produced average electrical powers of 5.7 μW/m 2 and plasmonically excited biofilms produced average electrical powers of 5.8 μW/m 2 , with individual biofilms producing as much as 12 μW/m 2

  3. A photosynthetic-plasmonic-voltaic cell: Excitation of photosynthetic bacteria and current collection through a plasmonic substrate

    Energy Technology Data Exchange (ETDEWEB)

    Samsonoff, Nathan; Ooms, Matthew D.; Sinton, David [Department of Mechanical and Industrial Engineering, and Institute for Sustainable Energy, University of Toronto, Toronto M5S 3G8 (Canada)

    2014-01-27

    Excitation of photosynthetic biofilms using surface-confined evanescent light fields enables energy dense photobioreactors, while electrode-adhered biofilms can provide electricity directly. Here, we demonstrate concurrent light delivery and electron transport through a plasmonically excited metal film. Biofilms of cyanobacterium Synechococcus bacillaris on 50-nm gold films are excited via the Kretschmann configuration at λ = 670 nm. Cells show light/dark response to plasmonic excitation and grow denser biofilms, closer to the electrode surface, as compared to the direct irradiated case. Directly irradiated biofilms produced average electrical powers of 5.7 μW/m{sup 2} and plasmonically excited biofilms produced average electrical powers of 5.8 μW/m{sup 2}, with individual biofilms producing as much as 12 μW/m{sup 2}.

  4. An electromagnetic compressive force by cell exciter stimulates chondrogenic differentiation of bone marrow-derived mesenchymal stem cells.

    Science.gov (United States)

    Park, Sang-Hyug; Sim, Woo Young; Park, Sin Wook; Yang, Sang Sik; Choi, Byung Hyune; Park, So Ra; Park, Kwideok; Min, Byoung-Hyun

    2006-11-01

    In this study, we present a biological micro-electromechanical system and its application to the chondrogenic differentiation of rabbit bone marrow-derived mesenchymal stem cells (MSCs). Actuated by an electromagnetic force, the micro cell exciter was designed to deliver a cyclic compressive load (CCL) with various magnitudes. Two major parts in the system are an actuator and a cartridge-type chamber. The former has a permanent magnet and coil, and the latter is equipped with 7 sample dishes and 7 metal caps. Mixed with a 2.4% alginate solution, the alginate/MSC layers were positioned in the sample dishes; the caps contained chondrogenic defined medium without transforming growth factor-beta (TGF-beta). Once powered, the actuator coil-derived electromagnetic force pulled the metal caps down, compressing the samples. The cyclic load was given at 1-Hz frequency for 10 min twice a day. Samples in the dishes without a cap served as a control. The samples were analyzed at 3, 5, and 7 days after stimulation for cell viability, biochemical assays, histologic features, immunohistochemistry, and gene expression of the chondrogenic markers. Applied to the alginate/MSC layer, the CCL system enhanced the synthesis of cartilage-specific matrix proteins and the chondrogenic markers, such as aggrecan, type II collagen, and Sox9. We found that the micromechanically exerted CCL by the cell exciter was very effective in enhancing the chondrogenic differentiation of MSCs, even without using exogenous TGF-beta.

  5. Curcumin mediates anticancer effects by modulating multiple cell signaling pathways.

    Science.gov (United States)

    Kunnumakkara, Ajaikumar B; Bordoloi, Devivasha; Harsha, Choudhary; Banik, Kishore; Gupta, Subash C; Aggarwal, Bharat B

    2017-08-01

    Curcumin, a component of a spice native to India, was first isolated in 1815 by Vogel and Pelletier from the rhizomes of Curcuma longa (turmeric) and, subsequently, the chemical structure of curcumin as diferuloylmethane was reported by Milobedzka et al. [(1910) 43., 2163-2170]. Since then, this polyphenol has been shown to exhibit antioxidant, anti-inflammatory, anticancer, antiviral, antibacterial, and antifungal activities. The current review primarily focuses on the anticancer potential of curcumin through the modulation of multiple cell signaling pathways. Curcumin modulates diverse transcription factors, inflammatory cytokines, enzymes, kinases, growth factors, receptors, and various other proteins with an affinity ranging from the pM to the mM range. Furthermore, curcumin effectively regulates tumor cell growth via modulation of numerous cell signaling pathways and potentiates the effect of chemotherapeutic agents and radiation against cancer. Curcumin can interact with most of the targets that are modulated by FDA-approved drugs for cancer therapy. The focus of this review is to discuss the molecular basis for the anticancer activities of curcumin based on preclinical and clinical findings. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  6. Probiotic Modulation of Innate Cell Pathogen Sensing and Signaling Events

    Directory of Open Access Journals (Sweden)

    Amy Llewellyn

    2017-10-01

    Full Text Available There is a growing body of evidence documenting probiotic bacteria to have a beneficial effect to the host through their ability to modulate the mucosal immune system. Many probiotic bacteria can be considered to act as either immune activators or immune suppressors, which have appreciable influence on homeostasis, inflammatory- and suppressive-immunopathology. What is becoming apparent is the ability of these probiotics to modulate innate immune responses via direct or indirect effects on the signaling pathways that drive these activatory or suppressive/tolerogenic mechanisms. This review will focus on the immunomodulatory role of probiotics on signaling pathways in innate immune cells: from positive to negative regulation associated with innate immune cells driving gut mucosal functionality. Research investigations have shown probiotics to modulate innate functionality in many ways including, receptor antagonism, receptor expression, binding to and expression of adaptor proteins, expression of negative regulatory signal molecules, induction of micro-RNAs, endotoxin tolerisation and finally, the secretion of immunomodulatory proteins, lipids and metabolites. The detailed understanding of the immunomodulatory signaling effects of probiotic strains will facilitate strain-specific selective manipulation of innate cell signal mechanisms in the modulation of mucosal adjuvanticity, immune deviation and tolerisation in both healthy subjects and patients with inflammatory and suppressive pathology.

  7. Probiotic Modulation of Innate Cell Pathogen Sensing and Signaling Events

    Science.gov (United States)

    Llewellyn, Amy; Foey, Andrew

    2017-01-01

    There is a growing body of evidence documenting probiotic bacteria to have a beneficial effect to the host through their ability to modulate the mucosal immune system. Many probiotic bacteria can be considered to act as either immune activators or immune suppressors, which have appreciable influence on homeostasis, inflammatory- and suppressive-immunopathology. What is becoming apparent is the ability of these probiotics to modulate innate immune responses via direct or indirect effects on the signaling pathways that drive these activatory or suppressive/tolerogenic mechanisms. This review will focus on the immunomodulatory role of probiotics on signaling pathways in innate immune cells: from positive to negative regulation associated with innate immune cells driving gut mucosal functionality. Research investigations have shown probiotics to modulate innate functionality in many ways including, receptor antagonism, receptor expression, binding to and expression of adaptor proteins, expression of negative regulatory signal molecules, induction of micro-RNAs, endotoxin tolerisation and finally, the secretion of immunomodulatory proteins, lipids and metabolites. The detailed understanding of the immunomodulatory signaling effects of probiotic strains will facilitate strain-specific selective manipulation of innate cell signal mechanisms in the modulation of mucosal adjuvanticity, immune deviation and tolerisation in both healthy subjects and patients with inflammatory and suppressive pathology. PMID:29065562

  8. Excitable waves at the margin of the contact area between a cell and a substrate

    International Nuclear Information System (INIS)

    Ali, O; Albigès-Rizo, C; Block, M R; Fourcade, B

    2009-01-01

    In this paper, we study a new physical mechanism to generate an activator field which signals the extreme margin of the contact area between an adherent cell and the substrate. This mechanism is based on the coupling between the adhesive bridges connecting the substrate to the cytoskeleton and a cytosolic activator. Once activated by adhesion on the adhesive bridges, this activator is free to diffuse on the membrane. We propose that this activator is part of the mecano-transduction pathway which links adhesion to actin polymerization and, thus, to cellular motility. The consequences of our model are as follows: (a) the activator is localized at the rim of the contact area, (b) the adhesion is reinforced at the margin of the contact area between the cell and the substrate, (c) excitable waves of the activator can propagate along the adhesion rim

  9. High Excitation Transfer Efficiency from Energy Relay Dyes in Dye-Sensitized Solar Cells

    KAUST Repository

    Hardin, Brian E.

    2010-08-11

    The energy relay dye, 4-(Dicyanomethylene)-2-methyl-6-(4- dimethylaminostyryl)-4H-pyran (DCM), was used with a near-infrared sensitizing dye, TT1, to increase the overall power conversion efficiency of a dye-sensitized solar cell (DSC) from 3.5% to 4.5%. The unattached DCM dyes exhibit an average excitation transfer efficiency (EÌ?TE) of 96% inside TT1-covered, mesostructured TiO2 films. Further performance increases were limited by the solubility of DCM in an acetonitrile based electrolyte. This demonstration shows that energy relay dyes can be efficiently implemented in optimized dye-sensitized solar cells, but also highlights the need to design highly soluble energy relay dyes with high molar extinction coefficients. © 2010 American Chemical Society.

  10. ANALYSIS OF PROCESSES IN AN INDEPENDENT GENERATOR WITH A NONCONTACT CASCADE THREE-PHASE MODULATED EXCITER VIA A STAR-CONNECTED CIRCUIT WITH A COMMON MODULATOR PHASE CONNECTION UNDER OPERATION TO AN INDUCTION MOTORS SITE

    Directory of Open Access Journals (Sweden)

    K.M. Vasyliv

    2013-04-01

    Full Text Available By means of a mathematical experiment, electromagnetic and electromechanical processes in an independent electric power supply system based on an asynchronized generator with a three-phase modulated exciter are investigated. The processes are analyzed to specify the working capacity of the power supply system during its operation to an induction motors site. Regularities of the electromagnetic and electromechanical processes behavior versus load intensity and the switch control system parameters are identified.

  11. Mapping the local organization of cell membranes using excitation-polarization-resolved confocal fluorescence microscopy.

    Science.gov (United States)

    Kress, Alla; Wang, Xiao; Ranchon, Hubert; Savatier, Julien; Rigneault, Hervé; Ferrand, Patrick; Brasselet, Sophie

    2013-07-02

    Fluorescence anisotropy and linear dichroism imaging have been widely used for imaging biomolecular orientational distributions in protein aggregates, fibrillar structures of cells, and cell membranes. However, these techniques do not give access to complete orientational order information in a whole image, because their use is limited to parts of the sample where the average orientation of molecules is known a priori. Fluorescence anisotropy is also highly sensitive to depolarization mechanisms such as those induced by fluorescence energy transfer. A fully excitation-polarization-resolved fluorescence microscopy imaging that relies on the use of a tunable incident polarization and a nonpolarized detection is able to circumvent these limitations. We have developed such a technique in confocal epifluorescence microscopy, giving access to new regions of study in the complex and heterogeneous molecular organization of cell membranes. Using this technique, we demonstrate morphological changes at the subdiffraction scale in labeled COS-7 cell membranes whose cytoskeleton is perturbed. Molecular orientational order is also seen to be affected by cholesterol depletion, reflecting the strong interplay between lipid-packing regions and their nearby cytoskeleton. This noninvasive optical technique can reveal local organization in cell membranes when used as a complement to existing methods such as generalized polarization. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  12. New test and characterization methods for PV modules and cells

    Energy Technology Data Exchange (ETDEWEB)

    Van Aken, B.; Sommeling, P. [ECN Solar Energy, Petten (Netherlands); Scholten, H. [Solland, Heerlen (Netherlands); Muller, J. [Moser-Baer, Eindhoven (Netherlands); Grossiord, N. [Holst Centre, Eindhoven (Netherlands); Smits, C.; Blanco Mantecon, M. [Holland Innovative, Eindhoven (Netherlands); Verheijen, M.; Van Berkum, J. [Philips Innovation Services, Eindhoven (Netherlands)

    2012-08-15

    The results of the project geZONd (shared facility for solar module analysis and reliability testing) are described. The project was set up by Philips, ECN, Holst, Solland, OM and T and Holland Innovative. The partners have shared most of their testing and analysis equipment for PV modules and cells, and together developed new or improved methods (including the necessary application know-how). This enables faster and more efficient innovation projects for each partner, and via commercial exploitation for other interested parties. The project has concentrated on five failure modes: corrosion, delamination, moisture ingress, UV irradiation, and mechanical bending. Test samples represented all main PV technologies: wafer based PV and rigid and flexible thin-film PV. Breakthroughs are in very early detection of corrosion, in quantitative characterization of adhesion, in-situ detection of humidity and oxygen inside modules, and ultra-fast screening of materials on UV stability.

  13. Charge-Transfer Dynamics in the Lowest Excited State of a Pentacene–Fullerene Complex: Implications for Organic Solar Cells

    KAUST Repository

    Joseph, Saju

    2017-10-02

    We characterize the dynamic nature of the lowest excited state in a pentacene/C60 complex on the femtosecond time scale, via a combination of ab initio molecular dynamics and time-dependent density functional theory. We analyze the correlations between the molecular vibrations of the complex and the oscillations in the electron-transfer character of its lowest excited state, which point to vibration-induced coherences between the (pentacene-based) local-excitation (LE) state and the complex charge-transfer (CT) state. We discuss the implications of our results on this model system for the exciton-dissociation process in organic solar cells.

  14. T cell motility as modulator of interactions with dendritic cells

    Directory of Open Access Journals (Sweden)

    Jens Volker Stein

    2015-11-01

    Full Text Available It is well established that the balance of costimulatory and inhibitory signals during interactions with dendritic cells (DCs determines T cell transition from a naïve to an activated or tolerant/anergic status. While many of these molecular interactions are well reproduced in reductionist in vitro assays, the highly dynamic motility of naïve T cells in lymphoid tissue acts as an additional lever to fine-tune their activation threshold. T cell detachment from DCs providing suboptimal stimulation allows them to search for DCs with higher levels of stimulatory signals, while storing a transient memory of short encounters. In turn, adhesion of weakly reactive T cells to DCs presenting pMHC with low affinity is prevented by lipid mediators. Finally, controlled recruitment of CD8+ T cells to cognate DC – CD4+ T cell clusters shapes memory T cell formation and the quality of the immune response. Dynamic physiological lymphocyte motility therefore constitutes a mechanism to mitigate low avidity T cell activation and to improve the search for optimal DCs, while contributing to peripheral tolerance induction in the absence of inflammation.

  15. Comparison of photovoltaic cell temperatures in modules operating with exposed and enclosed back surfaces

    Science.gov (United States)

    Namkoong, D.; Simon, F. F.

    1981-01-01

    Four different photovoltaic module designs were tested to determine the cell temperature of each design. The cell temperatures were compared to those obtained on identical design, using the same nominal operating cell temperature (NOCT) concept. The results showed that the NOCT procedure does not apply to the enclosed configurations due to continuous transient conditions. The enclosed modules had higher cell temperatures than the open modules, and insulated modules higher than the uninsulated. The severest performance loss - when translated from cell temperatures - 17.5 % for one enclosed, insulated module as a compared to that module mounted openly.

  16. B cells as a target of immune modulation

    Directory of Open Access Journals (Sweden)

    Hawker Kathleen

    2009-01-01

    Full Text Available B cells have recently been identified as an integral component of the immune system; they play a part in autoimmunity through antigen presentation, antibody secretion, and complement activation. Animal models of multiple sclerosis (MS suggest that myelin destruction is partly mediated through B cell activation (and plasmablasts. MS patients with evidence of B cell involvement, as compared to those without, tend to have a worse prognosis. Finally, the significant decrease in new gadolinium-enhancing lesions, new T2 lesions, and relapses in MS patients treated with rituximab (a monoclonal antibody against CD20 on B cells leads us to the conclusion that B cells play an important role in MS and that immune modulation of these cells may ameliorate the disease. This article will explore the role of B cells in MS and the rationale for the development of B cell-targeted therapeutics. MS is an immune-mediated disease that affects over 2 million people worldwide and is the number one cause of disability in young patients. Most therapeutic targets have focused on T cells; however, recently, the focus has shifted to the role of B cells in the pathogenesis of MS and the potential of B cells as a therapeutic target.

  17. Immune modulation through RNA interference-mediated silencing of CD40 in dendritic cells.

    Science.gov (United States)

    Karimi, Mohammad Hossein; Ebadi, Padideh; Pourfathollah, Ali Akbar; Soheili, Zahra Soheila; Samiee, Shahram; Ataee, Zahra; Tabei, Seyyed Ziyaoddin; Moazzeni, Seyed Mohammad

    2009-01-01

    RNA interference (RNAi) is an exciting mechanism for knocking down any target gene in transcriptional level. It is now clear that small interfering RNA (siRNA), a 19-21nt long dsRNA, can trigger a degradation process (RNAi) that specifically silences the expression of a cognate mRNA. Our findings in this study showed that down regulation of CD40 gene expression in dendritic cells (DCs) by RNAi culminated to immune modulation. Effective delivery of siRNA into DCs would be a reasonable method for the blocking of CD40 gene expression at the cell surface without any effect on other genes and cell cytotoxicity. The effects of siRNA against CD40 mRNA on the function and phenotype of DCs were investigated. The DCs were separated from the mice spleen and then cultured in vitro. By the means of Lipofectamine2000, siRNA was delivered to the cells and the efficacy of transfection was estimated by flow cytometry. By Annexine V and Propidium Iodide staining, we could evaluate the transfected cells viability. Also, the mRNA expression and protein synthesis were assessed by real-time PCR and flow cytometry, respectively. Knocking down the CD40 gene in the DCs caused an increase in IL-4 production, decrease in IL-12 production and allostimulation activity. All together, these effects would stimulate Th2 cytokines production from allogenic T-cells in vitro.

  18. Multi-color imaging of fluorescent nanodiamonds in living HeLa cells using direct electron-beam excitation.

    Science.gov (United States)

    Nawa, Yasunori; Inami, Wataru; Lin, Sheng; Kawata, Yoshimasa; Terakawa, Susumu; Fang, Chia-Yi; Chang, Huan-Cheng

    2014-03-17

    Multi-color, high spatial resolution imaging of fluorescent nanodiamonds (FNDs) in living HeLa cells has been performed with a direct electron-beam excitation-assisted fluorescence (D-EXA) microscope. In this technique, fluorescent materials are directly excited with a focused electron beam and the resulting cathodoluminescence (CL) is detected with nanoscale resolution. Green- and red-light-emitting FNDs were employed for two-color imaging, which were observed simultaneously in the cells with high spatial resolution. This technique could be applied generally for multi-color immunostaining to reveal various cell functions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Micropatterned Azopolymer Surfaces Modulate Cell Mechanics and Cytoskeleton Structure.

    Science.gov (United States)

    Rianna, Carmela; Ventre, Maurizio; Cavalli, Silvia; Radmacher, Manfred; Netti, Paolo A

    2015-09-30

    Physical and chemical characteristics of materials are important regulators of cell behavior. In particular, cell elasticity is a fundamental parameter that reflects the state of a cell. Surface topography finely modulates cell fate and function via adhesion mediated signaling and cytoskeleton generated forces. However, how topographies alter cell mechanics is still unclear. In this work we have analyzed the mechanical properties of peripheral and nuclear regions of NIH-3T3 cells on azopolymer substrates with different topographic patterns. Micrometer scale patterns in the form of parallel ridges or square lattices of surface elevations were encoded on light responsive azopolymer films by means of contactless optical methods. Cell mechanics was investigated by atomic force microscopy (AFM). Cells and consequently the cell cytoskeleton were oriented along the linear patterns affecting cytoskeletal structures, e.g., formation of actin stress fibers. Our data demonstrate that topographic substrate patterns are recognized by cells and mechanical information is transferred by the cytoskeleton. Furthermore, cytoskeleton generated forces deform the nucleus, changing its morphology that appears to be related to different mechanical properties in the nuclear region.

  20. Radio-frequency-modulated Rydberg states in a vapor cell

    Science.gov (United States)

    Miller, S. A.; Anderson, D. A.; Raithel, G.

    2016-05-01

    We measure strong radio-frequency (RF) electric fields using rubidium Rydberg atoms prepared in a room-temperature vapor cell as field sensors. Electromagnetically induced transparency is employed as an optical readout. We RF-modulate the 60{{{S}}}1/2 and 58{{{D}}}5/2 Rydberg states with 50 and 100 MHz fields, respectively. For weak to moderate RF fields, the Rydberg levels become Stark-shifted, and sidebands appear at even multiples of the driving frequency. In high fields, the adjacent hydrogenic manifold begins to intersect the shifted levels, providing rich spectroscopic structure suitable for precision field measurements. A quantitative description of strong-field level modulation and mixing of S and D states with hydrogenic states is provided by Floquet theory. Additionally, we estimate the shielding of DC electric fields in the interior of the glass vapor cell.

  1. Octopamine increases the excitability of neurons in the snail feeding system by modulation of inward sodium current but not outward potassium currents

    Directory of Open Access Journals (Sweden)

    Szabó Henriette

    2005-12-01

    Full Text Available Abstract Background Although octopamine has long been known to have major roles as both transmitter and modulator in arthropods, it has only recently been shown to be functionally important in molluscs, playing a role as a neurotransmitter in the feeding network of the snail Lymnaea stagnalis. The synaptic potentials cannot explain all the effects of octopamine-containing neurons on the feeding network, and here we test the hypothesis that octopamine is also a neuromodulator. Results The excitability of the B1 and B4 motoneurons in the buccal ganglia to depolarising current clamp pulses is significantly (P IA current and a sustained IK delayed-rectifier current, but neither was modulated by octopamine in any of these three buccal neurons. The fast inward current was eliminated in sodium – free saline and so is likely to be carried by sodium ions. 10 μM octopamine enhanced this current by 33 and 45% in the B1 and B4 motoneurons respectively (P Conclusion We conclude that octopamine is also a neuromodulator in snails, changing the excitability of the buccal neurons. This is supported by the close relationship from the voltage clamp data, through the quantitative simulation, to the action potential threshold, changing the properties of neurons in a rhythmic network. The increase in inward sodium current provides an explanation for the polycyclic modulation of the feeding system by the octopamine-containing interneurons, making feeding easier to initiate and making the feeding bursts more intense.

  2. Immune modules shared by innate lymphoid cells and T cells.

    Science.gov (United States)

    Robinette, Michelle L; Colonna, Marco

    2016-11-01

    In recent years, innate lymphoid cells (ILCs) have emerged as innate correlates to T cells. The similarities between ILCs and T cells indicate that lymphocytes of fundamentally distinct lineages can share core "immune modules" that encompass transcriptional circuitry and effector functions while using nonredundant complementary mechanisms of pattern recognition to enact these functions. We review modules currently recognized to be shared between ILCs and T cells. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  3. 76 FR 78313 - Crystalline Silicon Photovoltaic Cells and Modules From China

    Science.gov (United States)

    2011-12-16

    ...)] Crystalline Silicon Photovoltaic Cells and Modules From China Determinations On the basis of the record \\1... injured by reason of imports from China of crystalline silicon photovoltaic cells and modules, provided... imports of crystalline silicon photovoltaic cells and modules from China. Accordingly, effective October...

  4. 77 FR 72884 - Crystalline Silicon Photovoltaic Cells and Modules From China

    Science.gov (United States)

    2012-12-06

    ... Silicon Photovoltaic Cells and Modules From China Determinations On the basis of the record \\1\\ developed... imports of crystalline silicon photovoltaic cells and modules from China, provided for in subheadings 8501... silicon photovoltaic cells and modules from China. Chairman Irving A. Williamson and Commissioner Dean A...

  5. 76 FR 81914 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Science.gov (United States)

    2011-12-29

    ... Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's Republic of China: Postponement of... investigation of crystalline silicon photovoltaic cells, whether or not assembled into modules, from the People..., 2012. \\1\\ See Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the...

  6. Curcumin Modulates Pancreatic Adenocarcinoma Cell-Derived Exosomal Function

    Science.gov (United States)

    Osterman, Carlos J. Diaz; Lynch, James C.; Leaf, Patrick; Gonda, Amber; Ferguson Bennit, Heather R.; Griffiths, Duncan; Wall, Nathan R.

    2015-01-01

    Pancreatic cancer has the highest mortality rates of all cancer types. One potential explanation for the aggressiveness of this disease is that cancer cells have been found to communicate with one another using membrane-bound vesicles known as exosomes. These exosomes carry pro-survival molecules and increase the proliferation, survival, and metastatic potential of recipient cells, suggesting that tumor-derived exosomes are powerful drivers of tumor progression. Thus, to successfully address and eradicate pancreatic cancer, it is imperative to develop therapeutic strategies that neutralize cancer cells and exosomes simultaneously. Curcumin, a turmeric root derivative, has been shown to have potent anti-cancer and anti-inflammatory effects in vitro and in vivo. Recent studies have suggested that exosomal curcumin exerts anti-inflammatory properties on recipient cells. However, curcumin’s effects on exosomal pro-tumor function have yet to be determined. We hypothesize that curcumin will alter the pro-survival role of exosomes from pancreatic cancer cells toward a pro-death role, resulting in reduced cell viability of recipient pancreatic cancer cells. The main objective of this study was to determine the functional alterations of exosomes released by pancreatic cancer cells exposed to curcumin compared to exosomes from untreated pancreatic cancer cells. We demonstrate, using an in vitro cell culture model involving pancreatic adenocarcinoma cell lines PANC-1 and MIA PaCa-2, that curcumin is incorporated into exosomes isolated from curcumin-treated pancreatic cancer cells as observed by spectral studies and fluorescence microscopy. Furthermore, curcumin is delivered to recipient pancreatic cancer cells via exosomes, promoting cytotoxicity as demonstrated by Hoffman modulation contrast microscopy as well as AlamarBlue and Trypan blue exclusion assays. Collectively, these data suggest that the efficacy of curcumin may be enhanced in pancreatic cancer cells through

  7. The Design of a Five-Cell Superconducting RF Module with a PBG Coupler Cell

    International Nuclear Information System (INIS)

    Arsenyev, Sergey A.; Simakov, Evgenya I.

    2012-01-01

    We discuss the problem of incorporating a Photonic Band Gap (PBG) cell into a superconducting accelerating module of 5 cells designed for the operational frequency of 2.1 GHz. The reason for using a PBG cell is to provide a good accelerating mode confinement and good Higher Order Mode (HOM) suppression. PBG cell can potentially be used for placing HOM and fundamental mode couplers. However, because of the naturally higher ratio of the peak magnetic field to the accelerating field in the PBG cell, it should be designed to operate at a lower accelerating gradient than the other cells of the module. This ensures that the probability of quench in the PBG cell would be no higher than in other elliptical cells of the structure.

  8. Modulation of antigen presenting cell functions during chronic HPV infection

    Directory of Open Access Journals (Sweden)

    Abate Assefa Bashaw

    2017-12-01

    Full Text Available High-risk human papillomaviruses (HR-HPV infect basal keratinocytes, where in some individuals they evade host immune responses and persist. Persistent HR-HPV infection of the cervix causes precancerous neoplasia that can eventuate in cervical cancer. Dendritic cells (DCs are efficient in priming/cross-priming antigen-specific T cells and generating antiviral and antitumor cytotoxic CD8+ T cells. However, HR-HPV have adopted various immunosuppressive strategies, with modulation of DC function crucial to escape from the host adaptive immune response. HPV E6 and E7 oncoproteins alter recruitment and localization of epidermal DCs, while soluble regulatory factors derived from HPV-induced hyperplastic epithelium change DC development and influence initiation of specific cellular immune responses. This review focuses on current evidence for HR-HPV manipulation of antigen presentation in dendritic cells and escape from host immunity.

  9. HLA‐G modulates the radiosensitivity of human neoplastic cells

    International Nuclear Information System (INIS)

    Michelin, Severino; Gallegos, Cristina; Baffa Trasci, Sofía; Dubner, Diana; Favier, B.; Carosella, E.D.

    2011-01-01

    Tumor cells show a very broad range of radiosensitivities. The differential radiosensitivity may depend on many factors, being the efficiency to recognize and/or repair the DNA lesion, and the cell cycle control mechanisms, the most important (Jeggo and Lavin, 2009; Kumala et al., 2003). Human leukocyte antigen‐G (HLA‐G) is a non‐classical HLA class I molecule involved in fetus protection form the maternal immune system, transplant tolerance, and viral and tumoral immune escape (Carosella et al., 2008). It has been determined that gamma radiation modulates HLA‐G expression at the plasma membrane of human melanoma cells. However, its role in tumoral radiosensitivity has not been demonstrated yet. The objective of this work was to determine if the radiosensitivity of human neoplastic cell lines cultured in vitro was mediated by HLA‐G expression. (authors)

  10. 77 FR 17439 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Science.gov (United States)

    2012-03-26

    ... cells or solar cells assembled into modules or panels, and thus quantity is not recorded consistently in... silicon photovoltaic cells, whether or not assembled into modules (solar cells) from the People's Republic... History The Department initiated a countervailing duty (CVD) investigation of solar cells from the PRC on...

  11. Characterization and modulation of canine mast cell derived eicosanoids

    Science.gov (United States)

    Lin, Tzu-Yin; London, Cheryl A.

    2013-01-01

    Mast cells play an important role in both innate and acquired immunity as well as several pathological conditions including allergy, arthritis and neoplasia. They influence these processes by producing a variety of mediators including cytokines, chemokines and eicosanoids. Very little is currently known about the spectrum of inflammatory mediators, particularly eicosanoids (prostaglandins and leukotrienes), produced by canine mast cells. This is important since modulating mast cell derived eicosanoids may help in the treatment of autoimmune and inflammatory disorders. The purpose of this study was to investigate the spectrum of eicosanoids produced by normal canine mast cells and to evaluate the effects of cytokines and non-steroidal anti-inflammatory mediators (NSAIDS) on eicosanoid production and release. Canine bone marrow derived cultured mast cells (cBMCMCs) expressed COX-1, COX-2, and 5-LOX and synthesized and released PGD2, PGE2, LTB4, and LTC4 following activation by a variety of stimuli. The selective COX-2 NSAIDs carprofen (Rimadyl®) and deracoxib (Deramaxx®) inhibited PGD2 and PGE2 production but only slightly inhibited LTB4 and LTC4. The mixed COX-1/COX-2 inhibitor piroxicam blocked PGD2 and PGE2 production, but upregulated LTC4 following treatment while tepoxilan (Zubrin®), a pan COX/LOX inhibitor, markedly reduced the production of all eicosanoids. The LOX inhibitor nordihydroguaiaretic acid (NDGA) prevented LTB4/LTC4 release and BMBMC degranulation. Pre-incubation of cBMCMCs with IL-4 and SCF sensitized these cells to degranulation in response to substance P. In conclusion, canine BMCMCs produce an array of eicosanoids similar to those produced by mast cells from other species. Tepoxilan appeared to be the most effective NSAID for blocking eicosanoid production and thus may be useful for modulating mast cell mediated responses in dogs. PMID:20036014

  12. Surface plasmon excitation using a Fourier-transform infrared spectrometer: Live cell and bacteria sensing

    Science.gov (United States)

    Lirtsman, Vladislav; Golosovsky, Michael; Davidov, Dan

    2017-10-01

    We report an accessory for beam collimation to be used as a plug-in for a conventional Fourier-Transform Infrared (FTIR) spectrometer. The beam collimator makes use of the built-in focusing mirror of the FTIR spectrometer which focuses the infrared beam onto the pinhole mounted in the place usually reserved for the sample. The beam is collimated by a small parabolic mirror and is redirected to the sample by a pair of plane mirrors. The reflected beam is conveyed by another pair of plane mirrors to the built-in detector of the FTIR spectrometer. This accessory is most useful for the surface plasmon excitation. We demonstrate how it can be employed for label-free and real-time sensing of dynamic processes in bacterial and live cell layers. In particular, by measuring the intensity of the CO2 absorption peak one can assess the cell layer metabolism, while by measuring the position of the surface plasmon resonance one assesses the cell layer morphology.

  13. An excited-state intramolecular photon transfer fluorescence probe for localizable live cell imaging of cysteine

    Science.gov (United States)

    Liu, Wei; Chen, Wen; Liu, Si-Jia; Jiang, Jian-Hui

    2017-03-01

    Small molecule probes suitable for selective and specific fluorescence imaging of some important but low-concentration intracellular reactive sulfur species such as cysteine (Cys) pose a challenge in chemical biology. We present a readily available, fast-response fluorescence probe CHCQ-Ac, with 2-(5‧-chloro-2-hydroxyl-phenyl)-6-chloro-4(3 H)-quinazolinone (CHCQ) as the fluorophore and acrylate group as the functional moiety, that enables high-selectivity and high-sensitivity for detecting Cys in both solution and biological system. After specifically reacted with Cys, the probe undergoes a seven-membered intramolecular cyclization and released the fluorophore CHCQ with excited-state intramolecular photon transfer effect. A highly fluorescent, insoluble aggregate was then formed to facilitate high-sensitivity and high-resolution imaging. The results showed that probe CHCQ-Ac affords a remarkably large Stokes shift and can detect Cys under physiological pH condition with no interference from other analytes. Moreover, this probe was proved to have excellent chemical stability, low cytotoxicity and good cell permeability. Our design of this probe provides a novel potential tool to visualize and localize cysteine in bioimaging of live cells that would greatly help to explore various Cys-related physiological and pathological cellular processes in cell biology and diagnostics.

  14. Cell-Intrinsic Roles for Autophagy in Modulating CD4 T Cell Functions

    Directory of Open Access Journals (Sweden)

    Elise Jacquin

    2018-05-01

    Full Text Available The catabolic process of autophagy plays important functions in inflammatory and immune responses by modulating innate immunity and adaptive immunity. Over the last decade, a cell-intrinsic role for autophagy in modulating CD4 T cell functions and differentiation was revealed. After the initial observation of autophagosomes in effector CD4 T cells, further work has shown that not only autophagy levels are modulated in CD4 T cells in response to environmental signals but also that autophagy critically affects the biology of these cells. Mouse models of autophagy deletion in CD4 T cells have indeed shown that autophagy is essential for CD4 T cell survival and homeostasis in peripheral lymphoid organs. Furthermore, autophagy is required for CD4 T cell proliferation and cytokine production in response to T cell receptor activation. Recent developments have uncovered that autophagy controls CD4 T cell differentiation and functions. While autophagy is required for the maintenance of immunosuppressive functions of regulatory T cells, it restrains the differentiation of TH9 effector cells, thus limiting their antitumor and pro-inflammatory properties. We will here discuss these findings that collectively suggest that therapeutic strategies targeting autophagy could be exploited for the treatment of cancer and inflammatory diseases.

  15. Collective excitations in semiconductor superlattices and plasma modes of a two-dimensional electron gas with spatially modulated charge density

    International Nuclear Information System (INIS)

    Eliasson, G.L.

    1987-01-01

    The theory of collective excitations in semiconductor superlattices is formulated by using linear response theory. Different kinds of collective excitations in type I (GaAs-GaAlAs) and type II (GaSb-InAs) superlattices are surveyed. Special attention is paid to the presence of surface and finite-size effects. In calculating the dielectric matrix, the effect of different approximations of the system is discussed. The theory for inelastic length scattering (Raman scattering), and for Electron Energy Loss (EEL) due to collective excitations, is formulated. Calculations for several model systems are presented and the main features of the spectra are discussed. In part II the theory of collective excitations of a two-dimensional electron gas with a spatially periodic equilibrium density is formulated. As a first example a periodic array of two-dimensional electron gas strips with constant equilibrium density is studied. The integral equation that describes the charge fluctuations on the strips is derived and solved numerically. The spatial dependence of the density fluctuation across a single strip can be in the form of either propagating or evanescent waves

  16. Decorin binds myostatin and modulates its activity to muscle cells

    International Nuclear Information System (INIS)

    Miura, Takayuki; Kishioka, Yasuhiro; Wakamatsu, Jun-ichi; Hattori, Akihito; Hennebry, Alex; Berry, Carole J.; Sharma, Mridula; Kambadur, Ravi; Nishimura, Takanori

    2006-01-01

    Myostatin, a member of TGF-β superfamily of growth factors, acts as a negative regulator of skeletal muscle mass. The mechanism whereby myostatin controls the proliferation and differentiation of myogenic cells is mostly clarified. However, the regulation of myostatin activity to myogenic cells after its secretion in the extracellular matrix (ECM) is still unknown. Decorin, a small leucine-rich proteoglycan, binds TGF-β and regulates its activity in the ECM. Thus, we hypothesized that decorin could also bind to myostatin and participate in modulation of its activity to myogenic cells. In order to test the hypothesis, we investigated the interaction between myostatin and decorin by surface plasmon assay. Decorin interacted with mature myostatin in the presence of concentrations of Zn 2+ greater than 10 μM, but not in the absence of Zn 2+ . Kinetic analysis with a 1:1 binding model resulted in dissociation constants (K D ) of 2.02 x 10 -8 M and 9.36 x 10 -9 M for decorin and the core protein of decorin, respectively. Removal of the glycosaminoglycan chain by chondroitinase ABC digestion did not affect binding, suggesting that decorin could bind to myostatin with its core protein. Furthermore, we demonstrated that immobilized decorin could rescue the inhibitory effect of myostatin on myoblast proliferation in vitro. These results suggest that decorin could trap myostatin and modulate its activity to myogenic cells in the ECM

  17. Numerical study of induced current perturbations in the vicinity of excitable cells exposed to extremely low frequency magnetic fields

    International Nuclear Information System (INIS)

    Hassan, Noha; Chatterjee, Indira; Publicover, Nelson G; Craviso, Gale L

    2003-01-01

    Realistic three-dimensional cell morphologies were modelled to determine the current density induced in excitable cell culture preparations exposed to 60 Hz magnetic fields and to identify important factors that can influence the responses of cells to these fields. Cell morphologies representing single spherical adrenal chromaffin cells, single elongated smooth muscle cells and chromaffin cell aggregates in a Petri dish containing culture medium were modelled using the finite element method. The computations for a spherical cell revealed alterations in the magnitude and spatial distribution of the induced current density in the immediate vicinity of the cell. Maxima occurred at the equatorial sides and minima at the poles. Proximity of cells to each other as well as cell aggregate shape, size and orientation with respect to the induced current influenced the magnitude and spatial distribution of the induced current density. For an elongated cell, effects on the induced current density were highly dependent on cell orientation with respect to the direction of the induced current. These results provide novel insights into the perturbations in induced current that occur in excitable cell culture preparations and lay a foundation for understanding the mechanisms of interaction with extremely low frequency magnetic fields at the tissue level

  18. Ligand mobility modulates immunological synapse formation and T cell activation.

    Directory of Open Access Journals (Sweden)

    Chih-Jung Hsu

    Full Text Available T cell receptor (TCR engagement induces clustering and recruitment to the plasma membrane of many signaling molecules, including the protein tyrosine kinase zeta-chain associated protein of 70 kDa (ZAP70 and the adaptor SH2 domain-containing leukocyte protein of 76 kDa (SLP76. This molecular rearrangement results in formation of the immunological synapse (IS, a dynamic protein array that modulates T cell activation. The current study investigates the effects of apparent long-range ligand mobility on T cell signaling activity and IS formation. We formed stimulatory lipid bilayers on glass surfaces from binary lipid mixtures with varied composition, and characterized these surfaces with respect to diffusion coefficient and fluid connectivity. Stimulatory ligands coupled to these surfaces with similar density and orientation showed differences in their ability to activate T cells. On less mobile membranes, central supramolecular activation cluster (cSMAC formation was delayed and the overall accumulation of CD3ζ at the IS was reduced. Analysis of signaling microcluster (MC dynamics showed that ZAP70 MCs exhibited faster track velocity and longer trajectories as a function of increased ligand mobility, whereas movement of SLP76 MCs was relatively insensitive to this parameter. Actin retrograde flow was observed on all surfaces, but cell spreading and subsequent cytoskeletal contraction were more pronounced on mobile membranes. Finally, increased tyrosine phosphorylation and persistent elevation of intracellular Ca(2+ were observed in cells stimulated on fluid membranes. These results point to ligand mobility as an important parameter in modulating T cell responses.

  19. Excitation of quasi-electrostatic modes in a magnetized plasma by a modulated hollow E-beam

    International Nuclear Information System (INIS)

    Ezzeddine, A.; Smullin, L.D.

    1982-01-01

    The power radiated into the modes of an infinite magnetized plasma by a modulated hollow electron beam is calculated for the cases of cold and warm plasmas. The beam is assumed to be sinusoidally density modulated and the induced fluctuating electric field is strong enough to quench any beam plasma interaction. Numerical results are presented for the power deposited into the plasma at frequencies near the lower hybrid frequency for different beam plasma parameters

  20. Dynamical heat transport amplification in a far-field thermal transistor of VO{sub 2} excited with a laser of modulated intensity

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez-Miranda, Jose, E-mail: jose.ordonez@cnrs.pprime.fr; Ezzahri, Younès; Drevillon, Jérémie; Joulain, Karl [Institut Pprime, CNRS, Université de Poitiers, ISAE-ENSMA, F-86962 Futuroscope Chasseneuil (France)

    2016-05-28

    Far-field radiative heat transport in a thermal transistor made up of a vanadium dioxide base excited with a laser of modulated intensity is analytically studied and optimized. This is done by solving the equation of energy conservation for the steady-state and modulated components of the temperature and heat fluxes that the base exchanges with the collector and emitter. The thermal bistability of VO{sub 2} is used to find an explicit condition on the laser intensity required to maximize these heat fluxes to values higher than the incident flux. For a 1 μm-thick base heated with a modulation frequency of 0.5 Hz, it is shown that both the DC and AC components of the heat fluxes are about 4 times the laser intensity, while the AC temperature remains an order of magnitude smaller than the DC one at around 343 K. Higher AC heat fluxes are obtained for thinner bases and/or lower frequencies. Furthermore, we find that out of the bistability temperatures associated with the dielectric-to-metal and metal-to-dielectric transitions of VO{sub 2}, the amplification of the collector-to-base and base-to-emitter heat fluxes is still possible, but at modulation frequencies lower than 0.1 Hz.

  1. Human lung mast cells modulate the functions of airway smooth muscle cells in asthma.

    Science.gov (United States)

    Alkhouri, H; Hollins, F; Moir, L M; Brightling, C E; Armour, C L; Hughes, J M

    2011-09-01

    Activated mast cell densities are increased on the airway smooth muscle in asthma where they may modulate muscle functions and thus contribute to airway inflammation, remodelling and airflow obstruction. To determine the effects of human lung mast cells on the secretory and proliferative functions of airway smooth muscle cells from donors with and without asthma. Freshly isolated human lung mast cells were stimulated with IgE/anti-IgE. Culture supernatants were collected after 2 and 24 h and the mast cells lysed. The supernatants/lysates were added to serum-deprived, subconfluent airway smooth muscle cells for up to 48 h. Released chemokines and extracellular matrix were measured by ELISA, proliferation was quantified by [(3) H]-thymidine incorporation and cell counting, and intracellular signalling by phospho-arrays. Mast cell 2-h supernatants reduced CCL11 and increased CXCL8 and fibronectin production from both asthmatic and nonasthmatic muscle cells. Leupeptin reversed these effects. Mast cell 24-h supernatants and lysates reduced CCL11 release from both muscle cell types but increased CXCL8 release by nonasthmatic cells. The 24-h supernatants also reduced asthmatic, but not nonasthmatic, muscle cell DNA synthesis and asthmatic cell numbers over 5 days through inhibiting extracellular signal-regulated kinase (ERK) and phosphatidylinositol (PI3)-kinase pathways. However, prostaglandins, thromboxanes, IL-4 and IL-13 were not involved in reducing the proliferation. Mast cell proteases and newly synthesized products differentially modulated the secretory and proliferative functions of airway smooth muscle cells from donors with and without asthma. Thus, mast cells may modulate their own recruitment and airway smooth muscle functions locally in asthma. © 2011 John Wiley & Sons A/S.

  2. Improving the Operational Stability of PBDTTTz-4 Polymer Solar Cells Modules by Electrode Modification

    DEFF Research Database (Denmark)

    Roth, Bérenger; Benatto, Gisele Alves dos Reis; Corazza, Michael

    2016-01-01

    PBDTTTz-4 is employed in the ambient manufacturing of fully Roll-to-Roll organic solar cell modules. Modules are manufactured using a novel silver nanowire electrode or a previously reported carbon electrode. The average PCE of carbon modules (3.07%) and AgNW modules (1.46%) shows that PBDTTTz-4...

  3. Diagnosis of basal cell carcinoma by two photon excited fluorescence combined with lifetime imaging

    Science.gov (United States)

    Fan, Shunping; Peng, Xiao; Liu, Lixin; Liu, Shaoxiong; Lu, Yuan; Qu, Junle

    2014-02-01

    Basal cell carcinoma (BCC) is the most common type of human skin cancer. The traditional diagnostic procedure of BCC is histological examination with haematoxylin and eosin staining of the tissue biopsy. In order to reduce complexity of the diagnosis procedure, a number of noninvasive optical methods have been applied in skin examination, for example, multiphoton tomography (MPT) and fluorescence lifetime imaging microscopy (FLIM). In this study, we explored two-photon optical tomography of human skin specimens using two-photon excited autofluorescence imaging and FLIM. There are a number of naturally endogenous fluorophores in skin sample, such as keratin, melanin, collagen, elastin, flavin and porphyrin. Confocal microscopy was used to obtain structures of the sample. Properties of epidermic and cancer cells were characterized by fluorescence emission spectra, as well as fluorescence lifetime imaging. Our results show that two-photon autofluorescence lifetime imaging can provide accurate optical biopsies with subcellular resolution and is potentially a quantitative optical diagnostic method in skin cancer diagnosis.

  4. Different types of bursting calcium oscillations in non-excitable cells

    International Nuclear Information System (INIS)

    Perc, Matjaz; Marhl, Marko

    2003-01-01

    In the paper different types of bursting Ca 2+ oscillations are presented. We analyse bursting behaviour in four recent mathematical models for Ca 2+ oscillations in non-excitable cells. Separately, regular, quasi-periodic, and chaotic bursting Ca 2+ oscillations are classified into several subtypes. The classification is based on the dynamics of separated fast and slow subsystems, the so-called fast-slow burster analysis. For regular bursting Ca 2+ oscillations two types of bursting are specified: Point-Point and Point-Cycle bursting. In particular, the slow passage effect, important for the Hopf-Hopf and SubHopf-SubHopf bursting subtypes, is explained by local divergence calculated for the fast subsystem. Quasi-periodic bursting Ca 2+ oscillations can be found in only one of the four studied mathematical models and appear via a homoclinic bifurcation with a homoclinic torus structure. For chaotic bursting Ca 2+ oscillations, we found that bursting patterns resulting from the period doubling root to chaos considerably differ from those appearing via intermittency and have to be treated separately. The analysis and classification of different types of bursting Ca 2+ oscillations provides better insight into mechanisms of complex intra- and intercellular Ca 2+ signalling. This improves our understanding of several important biological phenomena in cellular signalling like complex frequency-amplitude signal encoding and synchronisation of intercellular signal transduction between coupled cells in tissue

  5. Assessment of citalopram and escitalopram on neuroblastoma cell lines: Cell toxicity and gene modulation

    Science.gov (United States)

    Sakka, Laurent; Delétage, Nathalie; Chalus, Maryse; Aissouni, Youssef; Sylvain-Vidal, Valérie; Gobron, Stéphane; Coll, Guillaume

    2017-01-01

    Selective serotonin reuptake inhibitors (SSRI) are common antidepressants which cytotoxicity has been assessed in cancers notably colorectal carcinomas and glioma cell lines. We assessed and compared the cytotoxicity of 2 SSRI, citalopram and escitalopram, on neuroblastoma cell lines. The study was performed on 2 non-MYCN amplified cell lines (rat B104 and human SH-SY5Y) and 2 human MYCN amplified cell lines (IMR32 and Kelly). Citalopram and escitalopram showed concentration-dependent cytotoxicity on all cell lines. Citalopram was more cytotoxic than escitalopram. IMR32 was the most sensitive cell line. The absence of toxicity on human primary Schwann cells demonstrated the safety of both molecules for myelin. The mechanisms of cytotoxicity were explored using gene-expression profiles and quantitative real-time PCR (qPCR). Citalopram modulated 1 502 genes and escitalopram 1 164 genes with a fold change ≥ 2. 1 021 genes were modulated by both citalopram and escitalopram; 481 genes were regulated only by citalopram while 143 genes were regulated only by escitalopram. Citalopram modulated 69 pathways (KEGG) and escitalopram 42. Ten pathways were differently modulated by citalopram and escitalopram. Citalopram drastically decreased the expression of MYBL2, BIRC5 and BARD1 poor prognosis factors of neuroblastoma with fold-changes of -107 (pescitalopram. PMID:28467792

  6. Assessment of citalopram and escitalopram on neuroblastoma cell lines. Cell toxicity and gene modulation.

    Science.gov (United States)

    Sakka, Laurent; Delétage, Nathalie; Chalus, Maryse; Aissouni, Youssef; Sylvain-Vidal, Valérie; Gobron, Stéphane; Coll, Guillaume

    2017-06-27

    Selective serotonin reuptake inhibitors (SSRI) are common antidepressants which cytotoxicity has been assessed in cancers notably colorectal carcinomas and glioma cell lines. We assessed and compared the cytotoxicity of 2 SSRI, citalopram and escitalopram, on neuroblastoma cell lines. The study was performed on 2 non-MYCN amplified cell lines (rat B104 and human SH-SY5Y) and 2 human MYCN amplified cell lines (IMR32 and Kelly). Citalopram and escitalopram showed concentration-dependent cytotoxicity on all cell lines. Citalopram was more cytotoxic than escitalopram. IMR32 was the most sensitive cell line. The absence of toxicity on human primary Schwann cells demonstrated the safety of both molecules for myelin. The mechanisms of cytotoxicity were explored using gene-expression profiles and quantitative real-time PCR (qPCR). Citalopram modulated 1 502 genes and escitalopram 1 164 genes with a fold change ≥ 2. 1 021 genes were modulated by both citalopram and escitalopram; 481 genes were regulated only by citalopram while 143 genes were regulated only by escitalopram. Citalopram modulated 69 pathways (KEGG) and escitalopram 42. Ten pathways were differently modulated by citalopram and escitalopram. Citalopram drastically decreased the expression of MYBL2, BIRC5 and BARD1 poor prognosis factors of neuroblastoma with fold-changes of -107 (pescitalopram.

  7. DC-Evoked Modulation of Excitability of Myelinated Nerve Fibers and Their Terminal Branches; Differences in Sustained Effects of DC.

    Science.gov (United States)

    Kaczmarek, Dominik; Jankowska, Elzbieta

    2018-03-15

    Direct current (DC) evokes long-lasting changes in neuronal networks both presynaptically and postsynaptically and different mechanisms were proposed to be involved in them. Different mechanisms were also suggested to account for the different dynamics of presynaptic DC actions on myelinated nerve fibers stimulated before they entered the spinal gray matter and on their terminal branches. The aim of the present study was to examine whether these different dynamics might be related to differences in the involvement of K + channels. To this end, we compared effects of the K + channel blocker 4-amino-pyridine (4-AP) on DC-evoked changes in the excitability of afferent fibers stimulated within the dorsal columns (epidurally) and within their projection areas in the dorsal horn and motor nuclei (intraspinally). 4-AP was applied systemically in deeply anesthetized rats. DC-evoked increases in the excitability of epidurally stimulated afferent nerve fibers, and increases in field potentials evoked by these fibers, were not affected by 4-AP. In contrast, sustained decreases rather than increases in the excitability of intraspinally stimulated terminal nerve branches were evoked by local application of DC in conjunction with 4-AP. The study leads to the conclusion that 4-AP-sensitive K + channels contribute to the sustained DC-evoked post-polarization increases in the excitability at the level of terminal branches of nerve fibers but not of the nodes of Ranvier nor within the juxta-paranodal regions where other mechanisms would be involved in inducing the sustained DC-evoked changes. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

  8. Heart failure-induced changes of voltage-gated Ca2+ channels and cell excitability in rat cardiac postganglionic neurons.

    Science.gov (United States)

    Tu, Huiyin; Liu, Jinxu; Zhang, Dongze; Zheng, Hong; Patel, Kaushik P; Cornish, Kurtis G; Wang, Wei-Zhong; Muelleman, Robert L; Li, Yu-Long

    2014-01-15

    Chronic heart failure (CHF) is characterized by decreased cardiac parasympathetic and increased cardiac sympathetic nerve activity. This autonomic imbalance increases the risk of arrhythmias and sudden death in patients with CHF. We hypothesized that the molecular and cellular alterations of cardiac postganglionic parasympathetic (CPP) neurons located in the intracardiac ganglia and sympathetic (CPS) neurons located in the stellate ganglia (SG) possibly link to the cardiac autonomic imbalance in CHF. Rat CHF was induced by left coronary artery ligation. Single-cell real-time PCR and immunofluorescent data showed that L (Ca(v)1.2 and Ca(v)1.3), P/Q (Ca(v)2.1), N (Ca(v)2.2), and R (Ca(v)2.3) types of Ca2+ channels were expressed in CPP and CPS neurons, but CHF decreased the mRNA and protein expression of only the N-type Ca2+ channels in CPP neurons, and it did not affect mRNA and protein expression of all Ca2+ channel subtypes in the CPS neurons. Patch-clamp recording confirmed that CHF reduced N-type Ca2+ currents and cell excitability in the CPP neurons and enhanced N-type Ca2+ currents and cell excitability in the CPS neurons. N-type Ca2+ channel blocker (1 μM ω-conotoxin GVIA) lowered Ca2+ currents and cell excitability in the CPP and CPS neurons from sham-operated and CHF rats. These results suggest that CHF reduces the N-type Ca2+ channel currents and cell excitability in the CPP neurons and enhances the N-type Ca2+ currents and cell excitability in the CPS neurons, which may contribute to the cardiac autonomic imbalance in CHF.

  9. 77 FR 37877 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Science.gov (United States)

    2012-06-25

    ... Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's Republic of China: Preliminary... crystalline silicon photovoltaic cells, whether or not assembled into modules (``solar cells''), from the.... Correction In the Federal Register notice Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled...

  10. 77 FR 73017 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Science.gov (United States)

    2012-12-07

    ... photovoltaic cells, whether or not assembled into modules (solar cells), from the People's Republic of China... published its final determination in the countervailing duty investigation of solar cells from the PRC.\\2... covered by this order is crystalline silicon photovoltaic cells, and modules, laminates, and panels...

  11. Environmental testing of flat plate solar cell modules

    Science.gov (United States)

    Griffith, J.; Dumas, L.; Hoffman, A.

    1978-01-01

    Commercially available flat-plate solar cell modules have been subjected to a variety of environmental tests designed to simulate service conditions. Among the tests are those simulating heat and rain, wind-driven rains, humidity and freezing, humidity and heat, humidity with a voltage bias, salt fog, hail impact, and fungus infestation. Tests for optical surface soiling and the combined effects of temperature, humidity and UV irradiation are under development. A correlation has been demonstrated between degradation caused by the qualification tests and such observed field effects as power loss.

  12. Low-cost encapsulation materials for terrestrial solar cell modules

    Science.gov (United States)

    Cuddihy, E. F.; Baum, B.; Willis, P.

    1979-01-01

    The paper presents the findings of material surveys intended to identify low cost materials which could be functional as encapsulants (by 1986) for terrestrial solar cell modules. Economic analyses have indicated that in order to meet the low cost goal of $2.70 per sq m, some or all of the following material technologies must be developed or advanced: (1) UV screening outer covers; (2) elastomeric acrylics; (3) weatherproofing and waterproofing of structural wood and paper products; (4) transparent UV stabilizers for the UV-sensitive transparent pottants; and (5) cost-effective utilization of silicone and fluorocarbon materials.

  13. Recent History of Effector Use Modulates Practice-Dependent Changes in Corticospinal Excitability but Not Motor Learning.

    Science.gov (United States)

    Hussain, Sara J; Darling, Warren G; Cole, Kelly J

    2016-01-01

    The theory of homeostatic metaplasticity has significant implications for human motor cortical plasticity and motor learning. Previous work has shown that the extent of recent effector use before exogenously-induced plasticity can affect the direction, magnitude and variability of aftereffects. However, the impact of recent effector use on motor learning and practice-dependent plasticity is not known. We hypothesized that reducing effector use for 8 hours via hand/wrist immobilization would facilitate practice-dependent changes in corticospinal excitability and TMS-evoked thumb movement kinematics, while also promoting 24-hour retention of a ballistic motor skill. Subjects participated in a crossover study involving two conditions. During the immobilization condition, subjects wore a splint that restricted motion of the left hand and thumb for 8 hours. While wearing the splint, subjects were instructed to avoid using their left hand as much as possible. During the control condition, subjects did not wear a splint at any time nor were they instructed to avoid hand use. After either an 8 hour period of immobilization or normal hand use, we collected MEP and TMS-evoked thumb movement recruitment curves, and subjects practiced a ballistic motor skill involving rapid thumb extension. After motor practice, MEP and TMS-evoked thumb movement recruitment curves were re-tested. Retention of the motor skill was tested 30 minutes and 24 hours after motor practice. Reduced effector use did not impact pre-practice corticospinal excitability but did facilitate practice-dependent changes in corticospinal excitability, and this enhancement was specific to the trained muscle. In contrast, reducing effector use did not affect practice-dependent changes in TMS-evoked thumb movements nor did it promote acquisition or retention of the skill. Finally, we detected some associations between pre-practice excitability levels, plasticity effects and learning effects, but these did not reach

  14. History-dependent excitability as a single-cell substrate of transient memory for information discrimination.

    Directory of Open Access Journals (Sweden)

    Fabiano Baroni

    Full Text Available Neurons react differently to incoming stimuli depending upon their previous history of stimulation. This property can be considered as a single-cell substrate for transient memory, or context-dependent information processing: depending upon the current context that the neuron "sees" through the subset of the network impinging on it in the immediate past, the same synaptic event can evoke a postsynaptic spike or just a subthreshold depolarization. We propose a formal definition of History-Dependent Excitability (HDE as a measure of the propensity to firing in any moment in time, linking the subthreshold history-dependent dynamics with spike generation. This definition allows the quantitative assessment of the intrinsic memory for different single-neuron dynamics and input statistics. We illustrate the concept of HDE by considering two general dynamical mechanisms: the passive behavior of an Integrate and Fire (IF neuron, and the inductive behavior of a Generalized Integrate and Fire (GIF neuron with subthreshold damped oscillations. This framework allows us to characterize the sensitivity of different model neurons to the detailed temporal structure of incoming stimuli. While a neuron with intrinsic oscillations discriminates equally well between input trains with the same or different frequency, a passive neuron discriminates better between inputs with different frequencies. This suggests that passive neurons are better suited to rate-based computation, while neurons with subthreshold oscillations are advantageous in a temporal coding scheme. We also address the influence of intrinsic properties in single-cell processing as a function of input statistics, and show that intrinsic oscillations enhance discrimination sensitivity at high input rates. Finally, we discuss how the recognition of these cell-specific discrimination properties might further our understanding of neuronal network computations and their relationships to the distribution and

  15. Increased excitability of spinal pain reflexes and altered frequency-dependent modulation in the dopamine D3-receptor knockout mouse.

    Science.gov (United States)

    Keeler, Benjamin E; Baran, Christine A; Brewer, Kori L; Clemens, Stefan

    2012-12-01

    Frequency-dependent modulation and dopamine (DA) receptors strongly modulate neural circuits in the spinal cord. Of the five known DA receptor subtypes, the D3 receptor has the highest affinity to DA, and D3-mediated actions are mainly inhibitory. Using an animal model of spinal sensorimotor dysfunction, the D3 receptor knockout mouse (D3KO), we investigated the physiological consequences of D3 receptor dysfunction on pain-associated signaling pathways in the spinal cord, the initial integration site for the processing of pain signaling. In the D3KO spinal cord, inhibitory actions of DA on the proprioceptive monosynaptic stretch reflex are converted from depression to facilitation, but its effects on longer-latency and pain-associated reflex responses and the effects of FM have not been studied. Using behavioral approaches in vivo, we found that D3KO animals exhibit reduced paw withdrawal latencies to thermal pain stimulation (Hargreaves' test) over wild type (WT) controls. Electrophysiological and pharmacological approaches in the isolated spinal cord in vitro showed that constant current stimulation of dorsal roots at a pain-associated frequency was associated with a significant reduction in the frequency-dependent modulation of longer-latency reflex (LLRs) responses but not monosynaptic stretch reflexes (MSRs) in D3KO. Application of the D1 and D2 receptor agonists and the voltage-gated calcium-channel ligand, pregabalin, but not DA, was able to restore the frequency-dependent modulation of the LLR in D3KO to WT levels. Thus we demonstrate that nociception-associated LLRs and proprioceptive MSRs are differentially modulated by frequency, dopaminergics and the Ca(2+) channel ligand, pregabalin. Our data suggest a role for the DA D3 receptor in pain modulation and identify the D3KO as a possible model for increased nociception. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Scanless two-photon excitation of channelrhodopsin-2

    DEFF Research Database (Denmark)

    Papagiakoumou, E.; Anselmi, F.; Bègue, A.

    2010-01-01

    developed a method that combines generalized phase contrast with temporal focusing (TF-GPC) to shape two-photon excitation for this purpose. The illumination patterns are generated automatically from fluorescence images of neurons and shaped to cover the cell body or dendrites, or distributed groups...... of cells. The TF-GPC two-photon excitation patterns generated large photocurrents in Channelrhodopsin-2–expressing cultured cells and neurons and in mouse acute cortical slices. The amplitudes of the photocurrents can be precisely modulated by controlling the size and shape of the excitation volume and...

  17. Modulating cell-to-cell variability and sensitivity to death ligands by co-drugging

    International Nuclear Information System (INIS)

    Flusberg, Deborah A; Sorger, Peter K

    2013-01-01

    TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) holds promise as an anti-cancer therapeutic but efficiently induces apoptosis in only a subset of tumor cell lines. Moreover, even in clonal populations of responsive lines, only a fraction of cells dies in response to TRAIL and individual cells exhibit cell-to-cell variability in the timing of cell death. Fractional killing in these cell populations appears to arise not from genetic differences among cells but rather from differences in gene expression states, fluctuations in protein levels and the extent to which TRAIL-induced death or survival pathways become activated. In this study, we ask how cell-to-cell variability manifests in cell types with different sensitivities to TRAIL, as well as how it changes when cells are exposed to combinations of drugs. We show that individual cells that survive treatment with TRAIL can regenerate the sensitivity and death-time distribution of the parental population, demonstrating that fractional killing is a stable property of cell populations. We also show that cell-to-cell variability in the timing and probability of apoptosis in response to treatment can be tuned using combinations of drugs that together increase apoptotic sensitivity compared to treatment with one drug alone. In the case of TRAIL, modulation of cell-to-cell variability by co-drugging appears to involve a reduction in the threshold for mitochondrial outer membrane permeabilization. (paper)

  18. Cell Wall Remodeling Enzymes Modulate Fungal Cell Wall Elasticity and Osmotic Stress Resistance.

    Science.gov (United States)

    Ene, Iuliana V; Walker, Louise A; Schiavone, Marion; Lee, Keunsook K; Martin-Yken, Hélène; Dague, Etienne; Gow, Neil A R; Munro, Carol A; Brown, Alistair J P

    2015-07-28

    The fungal cell wall confers cell morphology and protection against environmental insults. For fungal pathogens, the cell wall is a key immunological modulator and an ideal therapeutic target. Yeast cell walls possess an inner matrix of interlinked β-glucan and chitin that is thought to provide tensile strength and rigidity. Yeast cells remodel their walls over time in response to environmental change, a process controlled by evolutionarily conserved stress (Hog1) and cell integrity (Mkc1, Cek1) signaling pathways. These mitogen-activated protein kinase (MAPK) pathways modulate cell wall gene expression, leading to the construction of a new, modified cell wall. We show that the cell wall is not rigid but elastic, displaying rapid structural realignments that impact survival following osmotic shock. Lactate-grown Candida albicans cells are more resistant to hyperosmotic shock than glucose-grown cells. We show that this elevated resistance is not dependent on Hog1 or Mkc1 signaling and that most cell death occurs within 10 min of osmotic shock. Sudden decreases in cell volume drive rapid increases in cell wall thickness. The elevated stress resistance of lactate-grown cells correlates with reduced cell wall elasticity, reflected in slower changes in cell volume following hyperosmotic shock. The cell wall elasticity of lactate-grown cells is increased by a triple mutation that inactivates the Crh family of cell wall cross-linking enzymes, leading to increased sensitivity to hyperosmotic shock. Overexpressing Crh family members in glucose-grown cells reduces cell wall elasticity, providing partial protection against hyperosmotic shock. These changes correlate with structural realignment of the cell wall and with the ability of cells to withstand osmotic shock. The C. albicans cell wall is the first line of defense against external insults, the site of immune recognition by the host, and an attractive target for antifungal therapy. Its tensile strength is conferred by

  19. Pacific ciguatoxin 1B-induced modulation of inflammatory mediators in a murine macrophage cell line.

    Science.gov (United States)

    Matsui, Mariko; Kumar-Roine, Shilpa; Darius, H Taiana; Chinain, Mireille; Laurent, Dominique; Pauillac, Serge

    2010-10-01

    Ciguatoxins, potent marine neurotoxins responsible for ciguatera, exert their numerous damaging effects through primary binding to the voltage-sensitive sodium channels of excitable cells. Using RAW 264.7 murine macrophages, we report the first experimental study presenting evidence that P-CTX-1B (the most potent congener from the Pacific) could modulate mRNA expression of pro- and anti-inflammatory cytokines as well as of inducible nitric oxide synthase (iNOS). P-CTX-1B, unlike other less potent marine polyether toxins, P-CTX-3C and PbTx-3, induced the overexpression of interleukin (IL)-1beta, IL-6, IL-10, tumor necrosis factor-alpha and iNOS with different magnitude and kinetic profiles, as compared to bacterial lipopolysaccharide (LPS). Unlike LPS, P-CTX-1B did not modulate IL-11 expression. In this report, we provide new evidence of the P-CTX-1B iNOS- and cytokines-inducing ability and shed new light on host response to potent neurotoxins. Copyright 2009 Elsevier Ltd. All rights reserved.

  20. Modulation of protein properties in living cells using nanobodies.

    Science.gov (United States)

    Kirchhofer, Axel; Helma, Jonas; Schmidthals, Katrin; Frauer, Carina; Cui, Sheng; Karcher, Annette; Pellis, Mireille; Muyldermans, Serge; Casas-Delucchi, Corella S; Cardoso, M Cristina; Leonhardt, Heinrich; Hopfner, Karl-Peter; Rothbauer, Ulrich

    2010-01-01

    Protein conformation is critically linked to function and often controlled by interactions with regulatory factors. Here we report the selection of camelid-derived single-domain antibodies (nanobodies) that modulate the conformation and spectral properties of the green fluorescent protein (GFP). One nanobody could reversibly reduce GFP fluorescence by a factor of 5, whereas its displacement by a second nanobody caused an increase by a factor of 10. Structural analysis of GFP-nanobody complexes revealed that the two nanobodies induce subtle opposing changes in the chromophore environment, leading to altered absorption properties. Unlike conventional antibodies, the small, stable nanobodies are functional in living cells. Nanobody-induced changes were detected by ratio imaging and used to monitor protein expression and subcellular localization as well as translocation events such as the tamoxifen-induced nuclear localization of estrogen receptor. This work demonstrates that protein conformations can be manipulated and studied with nanobodies in living cells.

  1. Plasmon-modulated photoluminescence from gold nanostructures and its dependence on plasmon resonance, excitation energy, and band structure

    NARCIS (Netherlands)

    Le Thi Ngoc, Loan; Wiedemair, Justyna; van den Berg, Albert; Carlen, Edwin

    2015-01-01

    Two distinct single-photon plasmon-modulated photoluminescence processes are generated from nanostructured gold surfaces by tuning the spectral overlap of the incident laser source, localized surface plasmon resonance band, and the interband transitions between the d and sp bands, near the X-and

  2. VAMP7 modulates ciliary biogenesis in kidney cells.

    Directory of Open Access Journals (Sweden)

    Christina M Szalinski

    Full Text Available Epithelial cells elaborate specialized domains that have distinct protein and lipid compositions, including the apical and basolateral surfaces and primary cilia. Maintaining the identity of these domains is required for proper cell function, and requires the efficient and selective SNARE-mediated fusion of vesicles containing newly synthesized and recycling proteins with the proper target membrane. Multiple pathways exist to deliver newly synthesized proteins to the apical surface of kidney cells, and the post-Golgi SNAREs, or VAMPs, involved in these distinct pathways have not been identified. VAMP7 has been implicated in apical protein delivery in other cell types, and we hypothesized that this SNARE would have differential effects on the trafficking of apical proteins known to take distinct routes to the apical surface in kidney cells. VAMP7 expressed in polarized Madin Darby canine kidney cells colocalized primarily with LAMP2-positive compartments, and siRNA-mediated knockdown modulated lysosome size, consistent with the known function of VAMP7 in lysosomal delivery. Surprisingly, VAMP7 knockdown had no effect on apical delivery of numerous cargoes tested, but did decrease the length and frequency of primary cilia. Additionally, VAMP7 knockdown disrupted cystogenesis in cells grown in a three-dimensional basement membrane matrix. The effects of VAMP7 depletion on ciliogenesis and cystogenesis are not directly linked to the disruption of lysosomal function, as cilia lengths and cyst morphology were unaffected in an MDCK lysosomal storage disorder model. Together, our data suggest that VAMP7 plays an essential role in ciliogenesis and lumen formation. To our knowledge, this is the first study implicating an R-SNARE in ciliogenesis and cystogenesis.

  3. THP-1 cell line: an in vitro cell model for immune modulation approach.

    Science.gov (United States)

    Chanput, Wasaporn; Mes, Jurriaan J; Wichers, Harry J

    2014-11-01

    THP-1 is a human leukemia monocytic cell line, which has been extensively used to study monocyte/macrophage functions, mechanisms, signaling pathways, and nutrient and drug transport. This cell line has become a common model to estimate modulation of monocyte and macrophage activities. This review attempts to summarize and discuss recent publications related to the THP-1 cell model. An overview on the biological similarities and dissimilarities between the THP-1 cell line and human peripheral blood mononuclear cell (PBMC) derived-monocytes and macrophages, as well as the advantages and disadvantages of the use of THP-1 cell line, is included. The review summarizes different published co-cultivation studies of THP-1 cells with other cell types, for instance, intestinal cells, adipocytes, T-lymphocytes, platelets, and vascular smooth muscle cells, which can be an option to study cell-cell interaction in vitro and can be an approach to better mimic in vivo conditions. Macrophage polarization is a relatively new topic which gains interest for which the THP-1 cell line also may be relevant. Besides that an overview of newly released commercial THP-1 engineered-reporter cells and THP-1 inflammasome test-cells is also given. Evaluation of recent papers leads to the conclusion that the THP-1 cell line has unique characteristics as a model to investigate/estimate immune-modulating effects of compounds in both activated and resting conditions of the cells. Although the THP-1 response can hint to potential responses that might occur ex vivo or in vivo, these should be, however, validated by in vivo studies to draw more definite conclusions. Copyright © 2013. Published by Elsevier B.V.

  4. Modification of circuit module of dye-sensitized solar cells (DSSC) for solar windows applications

    Science.gov (United States)

    Hastuti, S. D.; Nurosyid, F.; Supriyanto, A.; Suryana, R.

    2016-11-01

    This research has been conducted to obtain a modification of circuit producing the best efficiency of solar window modules as an alternative energy for daily usage. Solar window module was constructed by DSSC cells. In the previous research, solar window was created by a single cell of DSSC. Because it had small size, it could not be applied in the manufacture of solar window. Fabrication of solar window required a larger size of DSSC cell. Therefore, in the next research, a module of solar window was fabricated by connecting few cells of DSSC. It was done by using external electrical circuit method which was modified in the formation of series circuit and parallel circuit. Its fabrication used six cells of DSSC with the size of each cell was 1 cm × 9 cm. DSSC cells were sandwich structures constructed by an active layer of TiO2 as the working electrode, electrolyte solution, dye, and carbon layer. Characterization of module was started one by one, from one cell, two cells, three cells, until six cells of a module. It was conducted to recognize the increasing efficiency value as the larger surface area given. The efficiency of solar window module with series circuit was 0.06%, while using parallel circuit was 0.006%. Module with series circuit generated the higher voltage as the larger surface area. Meanwhile, module through parallel circuit tended to produce the constant voltage as the larger surface area. It was caused by the influence of resistance within the cable in each module. Module with circuit parallel used a longer cable than module with series circuit, so that its resistance increased. Therefore, module with parallel circuit generated voltage that tended to be constant and resulted small efficiency compared to the module with series circuit. It could be concluded that series external circuit was the best modification which could produce the higher efficiency.

  5. 77 FR 10478 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Science.gov (United States)

    2012-02-22

    ... Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's Republic of China: Postponement of... determination in the countervailing duty investigation of crystalline silicon photovoltaic cells, whether or not... Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's Republic of...

  6. 77 FR 4764 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Science.gov (United States)

    2012-01-31

    ... Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's Republic of China: Second... preliminary determination of the countervailing duty investigation of crystalline silicon photovoltaic cells... February 13, 2012.\\1\\ \\1\\ See Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules...

  7. 77 FR 31309 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Science.gov (United States)

    2012-05-25

    ... duty (``CVD'') investigations of solar cells stating that modules, laminates, and panels produced in a..., laminates, and panels produced in the PRC from solar cells produced in a third-country are not covered by... modules, laminates, and panels produced in a third-country from solar cells produced in the PRC are...

  8. Ouabain modulates cell contacts as well as functions that depend on cell adhesion.

    Science.gov (United States)

    Larre, Isabel; Contreras, Ruben G; Cereijido, Marcelino

    2011-01-01

    Ouabain, a toxic of vegetal origin used for centuries to treat heart failure, has recently been demonstrated to have an endogenous counterpart, most probably ouabain itself, which behaves as a hormone. Therefore, the challenge now is to discover the physiological role of hormone ouabain. We have recently shown that it modulates cell contacts such as gap junctions, which communicate neighboring cells, as well as tight junctions (TJs), which are one of the two differentiated features of epithelial cells, the other being apical/basolateral polarity. The importance of cell contacts can be hardly overestimated, since the most complex object in the universe, the brain, assembles itself depending on what cells contacts what other(s) how, when, and how is the molecular composition and special arrangement of the contacts involved. In the present chapter, we detail the protocols used to demonstrate the effect of ouabain on the molecular structure and functional properties of one of those cell-cell contacts: the TJ.

  9. Activation of CRH receptor type 1 expressed on glutamatergic neurons increases excitability of CA1 pyramidal neurons by the modulation of voltage-gated ion channels

    Directory of Open Access Journals (Sweden)

    Stephan eKratzer

    2013-07-01

    Full Text Available Corticotropin-releasing hormone (CRH plays an important role in a substantial number of patients with stress-related mental disorders, such as anxiety disorders and depression. CRH has been shown to increase neuronal excitability in the hippocampus, but the underlying mechanisms are poorly understood. The effects of CRH on neuronal excitability were investigated in acute hippocampal brain slices. Population spikes (PS and field excitatory postsynaptic potentials (fEPSP were evoked by stimulating Schaffer-collaterals and recorded simultaneously from the somatic and dendritic region of CA1 pyramidal neurons. CRH was found to increase PS amplitudes (mean  Standard error of the mean; 231.8  31.2% of control; n=10 while neither affecting fEPSPs (104.3 ± 4.2%; n=10 nor long-term potentiation (LTP. However, when Schaffer-collaterals were excited via action potentials (APs generated by stimulation of CA3 pyramidal neurons, CRH increased fEPSP amplitudes (119.8 ± 3.6%; n=8 and the magnitude of LTP in the CA1 region. Experiments in slices from transgenic mice revealed that the effect on PS amplitude is mediated exclusively by CRH receptor 1 (CRHR1 expressed on glutamatergic neurons. The effects of CRH on PS were dependent on phosphatase-2B, L- and T-type calcium channels and voltage-gated potassium channels but independent on intracellular Ca2+-elevation. In patch-clamp experiments, CRH increased the frequency and decay times of APs and decreased currents through A-type and delayed-rectifier potassium channels. These results suggest that CRH does not affect synaptic transmission per se, but modulates voltage-gated ion currents important for the generation of APs and hence elevates by this route overall neuronal activity.

  10. Inhomogeneous nuclear spin polarization induced by helicity-modulated optical excitation of fluorine-bound electron spins in ZnSe

    Science.gov (United States)

    Heisterkamp, F.; Greilich, A.; Zhukov, E. A.; Kirstein, E.; Kazimierczuk, T.; Korenev, V. L.; Yugova, I. A.; Yakovlev, D. R.; Pawlis, A.; Bayer, M.

    2015-12-01

    Optically induced nuclear spin polarization in a fluorine-doped ZnSe epilayer is studied by time-resolved Kerr rotation using resonant excitation of donor-bound excitons. Excitation with helicity-modulated laser pulses results in a transverse nuclear spin polarization, which is detected as a change of the Larmor precession frequency of the donor-bound electron spins. The frequency shift in dependence on the transverse magnetic field exhibits a pronounced dispersion-like shape with resonances at the fields of nuclear magnetic resonance of the constituent zinc and selenium isotopes. It is studied as a function of external parameters, particularly of constant and radio frequency external magnetic fields. The width of the resonance and its shape indicate a strong spatial inhomogeneity of the nuclear spin polarization in the vicinity of a fluorine donor. A mechanism of optically induced nuclear spin polarization is suggested based on the concept of resonant nuclear spin cooling driven by the inhomogeneous Knight field of the donor-bound electron.

  11. Steviol Glycosides Modulate Glucose Transport in Different Cell Types

    Science.gov (United States)

    Rizzo, Benedetta; Zambonin, Laura; Leoncini, Emanuela; Vieceli Dalla Sega, Francesco; Prata, Cecilia; Fiorentini, Diana; Hrelia, Silvana

    2013-01-01

    Extracts from Stevia rebaudiana Bertoni, a plant native to Central and South America, have been used as a sweetener since ancient times. Currently, Stevia extracts are largely used as a noncaloric high-potency biosweetener alternative to sugar, due to the growing incidence of type 2 diabetes mellitus, obesity, and metabolic disorders worldwide. Despite the large number of studies on Stevia and steviol glycosides in vivo, little is reported concerning the cellular and molecular mechanisms underpinning the beneficial effects on human health. The effect of four commercial Stevia extracts on glucose transport activity was evaluated in HL-60 human leukaemia and in SH-SY5Y human neuroblastoma cells. The extracts were able to enhance glucose uptake in both cellular lines, as efficiently as insulin. Our data suggest that steviol glycosides could act by modulating GLUT translocation through the PI3K/Akt pathway since treatments with both insulin and Stevia extracts increased the phosphorylation of PI3K and Akt. Furthermore, Stevia extracts were able to revert the effect of the reduction of glucose uptake caused by methylglyoxal, an inhibitor of the insulin receptor/PI3K/Akt pathway. These results corroborate the hypothesis that Stevia extracts could mimic insulin effects modulating PI3K/Akt pathway. PMID:24327825

  12. Dendritic cells modulate burn wound healing by enhancing early proliferation.

    Science.gov (United States)

    Vinish, Monika; Cui, Weihua; Stafford, Eboni; Bae, Leon; Hawkins, Hal; Cox, Robert; Toliver-Kinsky, Tracy

    2016-01-01

    Adequate wound healing is vital for burn patients to reduce the risk of infections and prolonged hospitalization. Dendritic cells (DCs) are antigen presenting cells that release cytokines and are central for the activation of innate and acquired immune responses. Studies have showed their presence in human burn wounds; however, their role in burn wound healing remains to be determined. This study investigated the role of DCs in modulating healing responses within the burn wound. A murine model of full-thickness contact burns was used to study wound healing in the absence of DCs (CD11c promoter-driven diphtheria toxin receptor transgenic mice) and in a DC-rich environment (using fms-like tyrosine kinase-3 ligand, FL- a DC growth factor). Wound closure was significantly delayed in DC-deficient mice and was associated with significant suppression of early cellular proliferation, granulation tissue formation, wound levels of TGFβ1 and formation of CD31+ vessels in healing wounds. In contrast, DC enhancement significantly accelerated early wound closure, associated with increased and accelerated cellular proliferation, granulation tissue formation, and increased TGFβ1 levels and CD31+ vessels in healing wounds. We conclude that DCs play an important role in the acceleration of early wound healing events, likely by secreting factors that trigger the proliferation of cells that mediate wound healing. Therefore, pharmacological enhancement of DCs may provide a therapeutic intervention to facilitate healing of burn wounds. © 2016 by the Wound Healing Society.

  13. Brassinosteroid regulates cell elongation by modulating gibberellin metabolism in rice.

    Science.gov (United States)

    Tong, Hongning; Xiao, Yunhua; Liu, Dapu; Gao, Shaopei; Liu, Linchuan; Yin, Yanhai; Jin, Yun; Qian, Qian; Chu, Chengcai

    2014-11-01

    Brassinosteroid (BR) and gibberellin (GA) are two predominant hormones regulating plant cell elongation. A defect in either of these leads to reduced plant growth and dwarfism. However, their relationship remains unknown in rice (Oryza sativa). Here, we demonstrated that BR regulates cell elongation by modulating GA metabolism in rice. Under physiological conditions, BR promotes GA accumulation by regulating the expression of GA metabolic genes to stimulate cell elongation. BR greatly induces the expression of D18/GA3ox-2, one of the GA biosynthetic genes, leading to increased GA1 levels, the bioactive GA in rice seedlings. Consequently, both d18 and loss-of-function GA-signaling mutants have decreased BR sensitivity. When excessive active BR is applied, the hormone mostly induces GA inactivation through upregulation of the GA inactivation gene GA2ox-3 and also represses BR biosynthesis, resulting in decreased hormone levels and growth inhibition. As a feedback mechanism, GA extensively inhibits BR biosynthesis and the BR response. GA treatment decreases the enlarged leaf angles in plants with enhanced BR biosynthesis or signaling. Our results revealed a previously unknown mechanism underlying BR and GA crosstalk depending on tissues and hormone levels, which greatly advances our understanding of hormone actions in crop plants and appears much different from that in Arabidopsis thaliana. © 2014 American Society of Plant Biologists. All rights reserved.

  14. Hierarchical feedback modules and reaction hubs in cell signaling networks.

    Science.gov (United States)

    Xu, Jianfeng; Lan, Yueheng

    2015-01-01

    Despite much effort, identification of modular structures and study of their organizing and functional roles remain a formidable challenge in molecular systems biology, which, however, is essential in reaching a systematic understanding of large-scale cell regulation networks and hence gaining capacity of exerting effective interference to cell activity. Combining graph theoretic methods with available dynamics information, we successfully retrieved multiple feedback modules of three important signaling networks. These feedbacks are structurally arranged in a hierarchical way and dynamically produce layered temporal profiles of output signals. We found that global and local feedbacks act in very different ways and on distinct features of the information flow conveyed by signal transduction but work highly coordinately to implement specific biological functions. The redundancy embodied with multiple signal-relaying channels and feedback controls bestow great robustness and the reaction hubs seated at junctions of different paths announce their paramount importance through exquisite parameter management. The current investigation reveals intriguing general features of the organization of cell signaling networks and their relevance to biological function, which may find interesting applications in analysis, design and control of bio-networks.

  15. Hierarchical feedback modules and reaction hubs in cell signaling networks.

    Directory of Open Access Journals (Sweden)

    Jianfeng Xu

    Full Text Available Despite much effort, identification of modular structures and study of their organizing and functional roles remain a formidable challenge in molecular systems biology, which, however, is essential in reaching a systematic understanding of large-scale cell regulation networks and hence gaining capacity of exerting effective interference to cell activity. Combining graph theoretic methods with available dynamics information, we successfully retrieved multiple feedback modules of three important signaling networks. These feedbacks are structurally arranged in a hierarchical way and dynamically produce layered temporal profiles of output signals. We found that global and local feedbacks act in very different ways and on distinct features of the information flow conveyed by signal transduction but work highly coordinately to implement specific biological functions. The redundancy embodied with multiple signal-relaying channels and feedback controls bestow great robustness and the reaction hubs seated at junctions of different paths announce their paramount importance through exquisite parameter management. The current investigation reveals intriguing general features of the organization of cell signaling networks and their relevance to biological function, which may find interesting applications in analysis, design and control of bio-networks.

  16. Hierarchical Feedback Modules and Reaction Hubs in Cell Signaling Networks

    Science.gov (United States)

    Xu, Jianfeng; Lan, Yueheng

    2015-01-01

    Despite much effort, identification of modular structures and study of their organizing and functional roles remain a formidable challenge in molecular systems biology, which, however, is essential in reaching a systematic understanding of large-scale cell regulation networks and hence gaining capacity of exerting effective interference to cell activity. Combining graph theoretic methods with available dynamics information, we successfully retrieved multiple feedback modules of three important signaling networks. These feedbacks are structurally arranged in a hierarchical way and dynamically produce layered temporal profiles of output signals. We found that global and local feedbacks act in very different ways and on distinct features of the information flow conveyed by signal transduction but work highly coordinately to implement specific biological functions. The redundancy embodied with multiple signal-relaying channels and feedback controls bestow great robustness and the reaction hubs seated at junctions of different paths announce their paramount importance through exquisite parameter management. The current investigation reveals intriguing general features of the organization of cell signaling networks and their relevance to biological function, which may find interesting applications in analysis, design and control of bio-networks. PMID:25951347

  17. Thin-film filament-based solar cells and modules

    Science.gov (United States)

    Tuttle, J. R.; Cole, E. D.; Berens, T. A.; Alleman, J.; Keane, J.

    1997-04-01

    This concept paper describes a patented, novel photovoltaic (PV) technology that is capable of achieving near-term commercialization and profitability based upon design features that maximize product performance while minimizing initial and future manufacturing costs. DayStar Technologies plans to exploit these features and introduce a product to the market based upon these differential positions. The technology combines the demonstrated performance and reliability of existing thin-film PV product with a cell and module geometry that cuts material usage by a factor of 5, and enhances performance and manufacturability relative to standard flat-plate designs. The target product introduction price is 1.50/Watt-peak (Wp). This is approximately one-half the cost of the presently available PV product. Additional features include: increased efficiency through low-level concentration, no scribe or grid loss, simple series interconnect, high voltage, light weight, high-throughput manufacturing, large area immediate demonstration, flexibility, modularity.

  18. Cell-to-module optical loss/gain analysis for various photovoltaic module materials through systematic characterization

    Science.gov (United States)

    Hsian Saw, Min; Khoo, Yong Sheng; Singh, Jai Prakash; Wang, Yan

    2017-08-01

    Reducing levelized cost of electricity (LCOE) is important for solar photovoltaics to compete against other energy sources. Thus, the focus should not only be on improving the solar cell efficiency, but also on continuously reducing the losses (or achieving gain) in the cell-to-module process. This can be achieved by choosing the appropriate module material and design. This paper presents a detailed and systematic characterization of various photovoltaic (PV) module materials (encapsulants, tabbing ribbons, and backsheets) and an evaluation of their impact on the output power of silicon wafer-based PV modules. Various characterization tools/techniques, such as UV-vis (reflectance) measurement, external quantum efficiency (EQE) measurement and EQE line-scan are used. Based on the characterization results, we use module materials with the best-evaluated optical performance to build “optimized modules”. Compared to the standard mini-module, an optical gain of more than 5% is achievable for the “optimized module” with selected module materials.

  19. Intestinal Epithelial Cells Modulate Antigen-Presenting Cell Responses to Bacterial DNA

    Science.gov (United States)

    Campeau, J. L.; Salim, S. Y.; Albert, E. J.; Hotte, N.

    2012-01-01

    Intestinal epithelial cells and antigen-presenting cells orchestrate mucosal innate immunity. This study investigated the role of bacterial DNA in modulating epithelial and bone marrow-derived antigen-presenting cells (BM-APCs) and subsequent T-lymphocyte responses. Murine MODE-K epithelial cells and BM-APCs were treated with DNA from either Bifidobacterium breve or Salmonella enterica serovar Dublin directly and under coculture conditions with CD4+ T cells. Apical stimulation of MODE-K cells with S. Dublin DNA enhanced secretion of cytokines from underlying BM-APCs and induced interleukin-17 (IL-17) and gamma interferon (IFN-γ) secretion from CD4+ T cells. Bacterial DNA isolated from either strain induced maturation and increased cytokine secretion from BM-APCs. Conditioned medium from S. Dublin-treated MODE-K cells elicited an increase in cytokine secretion similar to that seen for S. Dublin DNA. Treatment of conditioned medium from MODE-K cells with RNase and protease prevented the S. Dublin-induced increased cytokine secretion. Oral feeding of mice with B. breve DNA resulted in enhanced levels of colonic IL-10 and transforming growth factor β (TGFβ) compared with what was seen for mice treated with S. Dublin DNA. In contrast, feeding mice with S. Dublin DNA increased levels of colonic IL-17 and IL-12p70. T cells from S. Dublin DNA-treated mice secreted high levels of IL-12 and IFN-γ compared to controls and B. breve DNA-treated mice. These results demonstrate that intestinal epithelial cells are able to modulate subsequent antigen-presenting and T-cell responses to bacterial DNA with pathogenic but not commensal bacterial DNA inducing effector CD4+ T lymphocytes. PMID:22615241

  20. A COMPARATIVE ANALYSIS OF PROCESSES IN AN INDEPENDENT GENERATOR WITH A NONCONTACT CASCADE THREE-PHASE MODULATED EXCITER VIA A STAR-CONNECTED CIRCUIT UNDER ACTIVE-INDUCTIVE LOADING

    Directory of Open Access Journals (Sweden)

    K.M. Vasyliv

    2013-02-01

    Full Text Available By means of mathematical experiment, the author investigates electromagnetic and electromechanical processes in an independent electric power supply system based on an asynchronized generator with a three-phase modulated exciter. The processes are analyzed to specify the working capacity of the power supply system during its operation under active-inductive loading. Regularities of the electromagnetic and electromechanical processes behavior versus load intensity and the modulator scheme are identified.

  1. Simulated Microgravity Modulates Differentiation Processes of Embryonic Stem Cells

    Directory of Open Access Journals (Sweden)

    Vaibhav Shinde

    2016-04-01

    Full Text Available Background/Aims: Embryonic developmental studies under microgravity conditions in space are very limited. To study the effects of altered gravity on the embryonic development processes we established an in vitro methodology allowing differentiation of mouse embryonic stem cells (mESCs under simulated microgravity within a fast-rotating clinostat (clinorotation and capture of microarray-based gene signatures. Methods: The differentiating mESCs were cultured in a 2D pipette clinostat. The microarray and bioinformatics tools were used to capture genes that are deregulated by simulated microgravity and their impact on developmental biological processes. Results: The data analysis demonstrated that differentiation of mESCs in pipettes for 3 days resultet to early germ layer differentiation and then to the different somatic cell types after further 7 days of differentiation in the Petri dishes. Clinorotation influences differentiation as well as non-differentiation related biological processes like cytoskeleton related 19 genes were modulated. Notably, simulated microgravity deregulated genes Cyr61, Thbs1, Parva, Dhrs3, Jun, Tpm1, Fzd2 and Dll1 are involved in heart morphogenesis as an acute response on day 3. If the stem cells were further cultivated under normal gravity conditions (1 g after clinorotation, the expression of cardiomyocytes specific genes such as Tnnt2, Rbp4, Tnni1, Csrp3, Nppb and Mybpc3 on day 10 was inhibited. This correlated well with a decreasing beating activity of the 10-days old embryoid bodies (EBs. Finally, we captured Gadd45g, Jun, Thbs1, Cyr61and Dll1 genes whose expressions were modulated by simulated microgravity and by real microgravity in various reported studies. Simulated microgravity also deregulated genes belonging to the MAP kinase and focal dhesion signal transduction pathways. Conclusion: One of the most prominent biological processes affected by simulated microgravity was the process of cardiomyogenesis. The

  2. Insights into Host Cell Modulation and Induction of New Cells by the Corn Smut Ustilago maydis

    Directory of Open Access Journals (Sweden)

    Amey Redkar

    2017-05-01

    Full Text Available Many filamentous fungal pathogens induce drastic modulation of host cells causing abnormal infectious structures such as galls, or tumors that arise as a result of re-programming in the original developmental cell fate of a colonized host cell. Developmental consequences occur predominantly with biotrophic phytopathogens. This suggests that these host structures result as an outcome of efficient defense suppression and intimate fungal–host interaction to suit the pathogen’s needs for completion of its infection cycle. This mini-review mainly summarizes host cell re-programming that occurs in the Ustilago maydis – maize interaction, in which the pathogen deploys cell-type specific effector proteins with varying activities. The fungus senses the physiological status and identity of colonized host cells and re-directs the endogenous developmental program of its host. The disturbance of host cell physiology and cell fate leads to novel cell shapes, increased cell size, and/or the number of host cells. We particularly highlight the strategies of U. maydis to induce physiologically varied host organs to form the characteristic tumors in both vegetative and floral parts of maize.

  3. Evaluation of an inductively-coupled plasma with an extended-sleeve torch as an atomization cell for laser-excited fluorescence spectrometry.

    Science.gov (United States)

    Kosinski, M A; Uchida, H; Winefordner, J D

    1983-05-01

    An inductively-coupled plasma (ICP) with an extended-sleeve torch has been evaluated as an atomization cell for laser-excited fluorescence spectrometry. Limits of detection for 20 lines are given. The detection power is almost equivalent to that obtained by excitation with a hollow-cathode lamp. Interelement effects and spectral interferences are discussed.

  4. 76 FR 66748 - Crystalline Silicon Photovoltaic Cells and Modules From China; Institution of Antidumping and...

    Science.gov (United States)

    2011-10-27

    ... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 701-TA-481 and 731-TA-1190 (Preliminary)] Crystalline Silicon Photovoltaic Cells and Modules From China; Institution of Antidumping and Countervailing... imports from China of crystalline silicon photovoltaic cells and modules, provided for in subheadings 8541...

  5. 77 FR 63791 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled into Modules, from the People's...

    Science.gov (United States)

    2012-10-17

    ..., laminates, and panels produced in a third- country from solar cells produced in the PRC; however, modules, laminates, and panels produced in the PRC from solar cells produced in a third-country are not covered by the investigations. If an importer imports solar panels/modules that it claims do not contain solar...

  6. Resistin enhances the expansion of regulatory T cells through modulation of dendritic cells

    Directory of Open Access Journals (Sweden)

    Han Seung

    2010-06-01

    Full Text Available Abstract Background Resistin, a member of adipokine family, is known to be involved in the modulation of immune responses including inflammatory activity. Interestingly, resistin is secreted by adipocytes in mice and rats whereas it is secreted by leukocytes in humans. However, the mechanism behind the effect of resistin on the expansion of regulatory T cells (Tregs remains poorly understood. Therefore, we examined regulatory effect of resistin on the induction and cellular modification of Tregs. Results Both protein and mRNA expression of FoxP3, a representative marker of Tregs, increased in a dose-dependent manner when peripheral blood mononuclear cells were treated with resistin. At the same time, resistin had no direct effect on the induction of FoxP3 in CD4+ T cells, suggesting an indirect role through other cells type(s. Since DCs are an important player in the differentiation of T cells, we focused on the role of DCs in the modulation of Tregs by resistin. Resistin suppressed the expression of interferon regulatory factor (IRF-1 and its target cytokines, IL-6, IL-23p19 and IL-12p40, in DCs. Furthermore, FoxP3 expression is increased in CD4+ T cells when co-cultured with DCs and concomitantly treated with resistin. Conclusion Our results suggest that resistin induces expansion of functional Tregs only when co-cultured with DCs.

  7. Experimental and theoretical analysis of cell module output performance for a thermophotovoltaic system

    International Nuclear Information System (INIS)

    Xu, Xiaojie; Ye, Hong; Xu, Yexin; Shen, Mingrong; Zhang, Xiaojing; Wu, Xi

    2014-01-01

    Highlights: • An accurate theoretical model for thermophotovoltaic system is constructed. • Parallel connected module is superior if radiator temperature is uneven. • Series connected module is superior if cell temperature is uneven. • Short circuit current of series module rises when the shunt resistance decreases. • Fill factor is not always accurate to evaluate the module performance. - Abstract: An experimental thermophotovoltaic (TPV) system with a cylindrical-geometry radiator was established to test the output performances of modules under different conditions. The results demonstrate that the output performance of a cell module decreases when the combustion power increases because of the uneven temperature of the radiator or cells. On this basis, a theoretical model for a TPV system was constructed to compare the performance under different conditions of the series-connected (SC) module and the parallel-connected (PC) module, and was verified by the experimental results. The influences of the temperature gradient of the radiator or the cell module, and the series and shunt resistance of the TPV cell on the module performance were analyzed in detail. The results demonstrate that the PC module can effectively reduce the mismatch loss of output power caused by the uneven radiator temperature. The PC module, for instance, has a maximum output power of 2.54 times higher than that of the SC module when the radiator temperature difference is 500 K. However, the output performance of the module connected in series is superior to the PC module while the cell temperature is non-uniform. The output power of the SC module is 9.93% higher than that of the PC module at the cell temperature difference of 125 K. The short circuit current of the SC module is sensitive to the series and shunt resistance if the radiator temperature distribution is non-uniform. As the shunt resistance falls from ∞ to 0.5 Ω, the current varies from 1.757 A to 4.488 A when the

  8. Exosomes from asbestos-exposed cells modulate gene expression in mesothelial cells.

    Science.gov (United States)

    Munson, Phillip; Lam, Ying-Wai; Dragon, Julie; MacPherson, Maximilian; Shukla, Arti

    2018-03-19

    Asbestos exposure is a determinate cause of many diseases, such as mesothelioma, fibrosis, and lung cancer, and poses a major human health hazard. At this time, there are no identified biomarkers to demarcate asbestos exposure before the presentation of disease and symptoms, and there is only limited understanding of the underlying biology that governs asbestos-induced disease. In our study, we used exosomes, 30-140 nm extracellular vesicles, to gain insight into these knowledge gaps. As inhaled asbestos is first encountered by lung epithelial cells and macrophages, we hypothesize that asbestos-exposed cells secrete exosomes with signature proteomic cargo that can alter the gene expression of mesothelial cells, contributing to disease outcomes like mesothelioma. In the present study using lung epithelial cells (BEAS2B) and macrophages (THP-1), we first show that asbestos exposure causes changes in abundance of some proteins in the exosomes secreted from these cells. Furthermore, exposure of human mesothelial cells (HPM3) to these exosomes resulted in gene expression changes related to epithelial-to-mesenchymal transition and other cancer-related genes. This is the first report to indicate that asbestos-exposed cells secrete exosomes with differentially abundant proteins and that those exosomes have a gene-altering effect on mesothelial cells.-Munson, P., Lam, Y.-W., Dragon, J. MacPherson, M., Shukla, A. Exosomes from asbestos-exposed cells modulate gene expression in mesothelial cells.

  9. Ground and excited state properties of high performance anthocyanidin dyes-sensitized solar cells in the basic solutions

    Energy Technology Data Exchange (ETDEWEB)

    Prima, Eka Cahya [Advanced Functional Material Laboratory, Engineering Physics, Institut Teknologi Bandung (Indonesia); Computational Material Design and Quantum Engineering Laboratory, Engineering Physics, Institut Teknologi Bandung (Indonesia); International Program on Science Education, Universitas Pendidikan Indonesia (Indonesia); Yuliarto, Brian; Suyatman, E-mail: yatman@tf.itb.ac.id [Advanced Functional Material Laboratory, Engineering Physics, Institut Teknologi Bandung (Indonesia); Dipojono, Hermawan Kresno [Computational Material Design and Quantum Engineering Laboratory, Engineering Physics, Institut Teknologi Bandung (Indonesia)

    2015-09-30

    The aglycones of anthocyanidin dyes were previously reported to form carbinol pseudobase, cis-chalcone, and trans-chalcone due to the basic levels. The further investigations of ground and excited state properties of the dyes were characterized using density functional theory with PCM(UFF)/B3LYP/6-31+G(d,p) level in the basic solutions. However, to the best of our knowledge, the theoretical investigation of their potential photosensitizers has never been reported before. In this paper, the theoretical photovoltaic properties sensitized by dyes have been successfully investigated including the electron injections, the ground and excited state oxidation potentials, the estimated open circuit voltages, and the light harvesting efficiencies. The results prove that the electronic properties represented by dyes’ LUMO-HOMO levels will affect to the photovoltaic performances. Cis-chalcone dye is the best anthocyanidin aglycone dye with the electron injection spontaneity of −1.208 eV, the theoretical open circuit voltage of 1.781 V, and light harvesting efficiency of 56.55% due to the best HOMO-LUMO levels. Moreover, the ethanol solvent slightly contributes to the better cell performance than the water solvent dye because of the better oxidation potential stabilization in the ground state as well as in the excited state. These results are in good agreement with the known experimental report that the aglycones of anthocyanidin dyes in basic solvent are the high potential photosensitizers for dye-sensitized solar cell.

  10. 77 FR 35425 - Crystalline Silicon Photovoltaic Cells and Modules From China; Scheduling of the Final Phase of...

    Science.gov (United States)

    2012-06-13

    ... Silicon Photovoltaic Cells and Modules From China; Scheduling of the Final Phase of Countervailing Duty... silicon photovoltaic cells and modules, provided for in subheadings 8501.31.80, 8501.61.00, 8507.20.80... photovoltaic cells, and modules, laminates, and panels, consisting of crystalline silicon photovoltaic cells...

  11. Stimulus-dependent modulation of spike burst length in cat striate cortical cells.

    Science.gov (United States)

    DeBusk, B C; DeBruyn, E J; Snider, R K; Kabara, J F; Bonds, A B

    1997-07-01

    Burst activity, defined by groups of two or more spikes with intervals of cats. Bursting varied broadly across a population of 507 simple and complex cells. Half of this population had > or = 42% of their spikes contained in bursts. The fraction of spikes in bursts did not vary as a function of average firing rate and was stationary over time. Peaks in the interspike interval histograms were found at both 3-5 ms and 10-30 ms. In many cells the locations of these peaks were independent of firing rate, indicating a quantized control of firing behavior at two different time scales. The activity at the shorter time scale most likely results from intrinsic properties of the cell membrane, and that at the longer scale from recurrent network excitation. Burst frequency (bursts per s) and burst length (spikes per burst) both depended on firing rate. Burst frequency was essentially linear with firing rate, whereas burst length was a nonlinear function of firing rate and was also governed by stimulus orientation. At a given firing rate, burst length was greater for optimal orientations than for nonoptimal orientations. No organized orientation dependence was seen in bursts from lateral geniculate nucleus cells. Activation of cortical contrast gain control at low response amplitudes resulted in no burst length modulation, but burst shortening at optimal orientations was found in responses characterized by supersaturation. At a given firing rate, cortical burst length was shortened by microinjection of gamma-aminobutyric acid (GABA), and bursts became longer in the presence of N-methyl-bicuculline, a GABA(A) receptor blocker. These results are consistent with a model in which responses are reduced at nonoptimal orientations, at least in part, by burst shortening that is mediated by GABA. A similar mechanism contributes to response supersaturation at high contrasts via recruitment of inhibitory responses that are tuned to adjacent orientations. Burst length modulation can serve

  12. Combined Raman and continuous-wave-excited two-photon fluorescence cell imaging

    NARCIS (Netherlands)

    Uzunbajakava, N.; Otto, Cornelis

    2003-01-01

    We demonstrate a confocal optical microscope that combines cw two-photon-excited fluorescence microscopy with confocal Raman microscopy. With this microscope fast image acquisition with fluorescence imaging can be used to select areas of interest for subsequent chemical analysis with spontaneous

  13. Compatibility of copper-electroplated cells with Metal Wrap Through module materials

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, I.J.; Geerligs, L.J.; Olson, C.L.; Goris, M.J.A.A. [ECN Solar Energy, Petten (Netherlands)

    2013-10-16

    As part of the European FP7 RandD project 'Cu-PV', the compatibility of copper-electroplated metal wrapthrough (MWT) cells with conductive adhesives has been investigated. The objectives of this project include to reduce, by the use of copper plating, the amount of silver utilized in cell manufacturing, and to demonstrate the compatibility of high-power n-type back-contact module technology with copper-plated cells. The overall goal is to reduce the impact on the environment of cell and module manufacture. MWT module technology as developed by ECN uses conductive adhesive to make the interconnection between cells and a conductive backsheet foil. These adhesives have been proved to result in very reliable modules in the case of cells with fired silver metallization. To determine the compatibility of conductive adhesive with copper-plated cells, component tests were performed, followed by the manufacture of modules with copperplated cells and conductive adhesive interconnections. Climate chamber testing of these modules showed that the adhesive is compatible with the copper-plated cells. The next steps include further optimization of the plating process and additional testing at the module level.

  14. Morphological alterations in newly born dentate gyrus granule cells that emerge after status epilepticus contribute to make them less excitable.

    Directory of Open Access Journals (Sweden)

    Julián Tejada

    Full Text Available Computer simulations of external current stimulations of dentate gyrus granule cells of rats with Status Epilepticus induced by pilocarpine and control rats were used to evaluate whether morphological differences alone between these cells have an impact on their electrophysiological behavior. The cell models were constructed using morphological information from tridimensional reconstructions with Neurolucida software. To evaluate the effect of morphology differences alone, ion channel conductances, densities and distributions over the dendritic trees of dentate gyrus granule cells were the same for all models. External simulated currents were injected in randomly chosen dendrites belonging to one of three different areas of dentate gyrus granule cell molecular layer: inner molecular layer, medial molecular layer and outer molecular layer. Somatic membrane potentials were recorded to determine firing frequencies and inter-spike intervals. The results show that morphologically altered granule cells from pilocarpine-induced epileptic rats are less excitable than control cells, especially when they are stimulated in the inner molecular layer, which is the target area for mossy fibers that sprout after pilocarpine-induced cell degeneration. This suggests that morphological alterations may act as a protective mechanism to allow dentate gyrus granule cells to cope with the increase of stimulation caused by mossy fiber sprouting.

  15. Reciprocal modulation of mesenchymal stem cells and tumor cells promotes lung cancer metastasis

    Directory of Open Access Journals (Sweden)

    Giulia Fregni

    2018-03-01

    Full Text Available Metastasis is a multi-step process in which direct crosstalk between cancer cells and their microenvironment plays a key role. Here, we assessed the effect of paired tumor-associated and normal lung tissue mesenchymal stem cells (MSCs on the growth and dissemination of primary human lung carcinoma cells isolated from the same patients. We show that the tumor microenvironment modulates MSC gene expression and identify a four-gene MSC signature that is functionally implicated in promoting metastasis. We also demonstrate that tumor-associated MSCs induce the expression of genes associated with an aggressive phenotype in primary lung cancer cells and selectively promote their dissemination rather than local growth. Our observations provide insight into mechanisms by which the stroma promotes lung cancer metastasis. Keywords: Tumor-associated MSCs, lung cancer, metastasis, GREM1, LOXL2, ADAMTS12, ITGA11

  16. Reversible inactivation and excitation of nucleus raphe magnus can modulate tail blood flow of male Wistar rats in response to hypothermia.

    Science.gov (United States)

    Malakouti, Seyed Mansour; Kourosh Arami, Masoomeh; Sarihi, Abdorahman; Hajizadeh, Sohrab; Behzadi, Gila; Shahidi, Siamak; Komaki, Alireza; Heshmatian, Behnam; Vahabian, Mehrangiz

    2008-10-01

    The nucleus raphe magnus (NRM) is involved in thermoregulatory processing. There is a correlation between changes in the firing rates of the cells in the NRM and the application of the peripheral thermal stimulus. we examined the effect of reversible inactivation and excitation of NRM on mechanisms involved in tail blood flow (TBF) regulation in hypothermia. Hypothermia was induced in Male Wistar rats and cannula was implanted above the NRM. To evaluate the effect of nucleus inactivation on TBF, the amount of TBF was measured by Laser Doppler in hypothermic rats, before and after lidocaine microinjection into NRM. TBF was also measured after glutamate microinjection to assess the effect of nucleus excitation in hypothermic rats. Results indicated that after dropping TBF by hypothermia, microinjection of lidocaine into NRM significantly decreased TBF from 54.43 +- 5.7 to 46.81 +- 3.4, whereas glutamate microinjection caused a significant increase from 44.194 +- 0.6 to 98 +- 10.0 CONCLUSION: These data suggest that NRM have thermoregulatory effect in response to hypothermia.

  17. The Natural Killer Cell Cytotoxic Function Is Modulated by HIV-1 Accessory Proteins

    Directory of Open Access Journals (Sweden)

    Edward Barker

    2011-07-01

    Full Text Available Natural killer (NK cells’ major role in the control of viruses is to eliminate established infected cells. The capacity of NK cells to kill virus-infected cells is dependent on the interactions between ligands on the infected cell and receptors on the NK cell surface. Because of the importance of ligand-receptor interactions in modulating the NK cell cytotoxic response, HIV has developed strategies to regulate various NK cell ligands making the infected cell surprisingly refractory to NK cell lysis. This is perplexing because the HIV-1 accessory protein Vpr induces expression of ligands for the NK cell activating receptor, NKG2D. In addition, the accessory protein Nef removes the inhibitory ligands HLA-A and -B. The reason for the ineffective killing by NK cells despite the strong potential to eliminate infected cells is due to HIV-1 Vpu’s ability to down modulate the co-activation ligand, NTB-A, from the cell surface. Down modulation of NTB-A prevents efficient NK cell degranulation. This review will focus on the mechanisms through which the HIV-1 accessory proteins modulate their respective ligands, and its implication for NK cell killing of HIV-infected cells.

  18. High power n-type metal-wrap-through cells and modules using industrial processes

    Energy Technology Data Exchange (ETDEWEB)

    Guillevin, N.; Heurtault, B.J.B.; Geerligs, L.J.; Van Aken, B.B.; Bennett, I.J.; Jansen, M.J.; Weeber, A.W.; Bultman, J.H. [ECN Solar Energy, P.O. Box 1, NL-1755 ZG Petten (Netherlands); Jianming, Wang; Ziqian, Wang; Jinye, Zhai; Zhiliang, Wan; Shuquan, Tian; Wenchao, Zhao; Zhiyan, Hu; Gaofei, Li; Bo, Yu; Jingfeng, Xiong [Yingli Green Energy Holding Co.,Ltd. 3399 North Chaoyang Avenue, Baoding (China)

    2013-10-15

    This paper reviews our recent progress in the development of metal wrap through (MWT) cells and modules, produced from n-type Czochralski silicon wafers. The use of n-type silicon as base material allows for high efficiencies: for front emitter-contacted industrial cells, efficiencies above 20% have been reported. N-type MWT (nMWT) cells produced by industrial process technologies allow even higher efficiency due to reduced front metal coverage. Based on the same industrial technology, the efficiency of the bifacial n-MWT cells exceeds the efficiency of the n-type front-and-rear contact and bifacial 'Pasha' technology (n-Pasha) by 0.1-0.2% absolute, with a maximum nMWT efficiency of 20.1% so far. Additionally, full back-contacting of the MWT cells in a module results in reduced cell to module (CTM) fill factor losses. In a direct 60-cell module performance comparison, the n-MWT module, based on integrated backfoil, produced 3% higher power output than the comparable tabbed front emitter-contacted n-Pasha module. Thanks to reduced resistive losses in copper circuitry on the backfoil compared to traditional tabs, the CTM FF loss of the MWT module was reduced by about 2.2%abs. compared to the tabbed front emitter contact module. A full-size module made using MWT cells of 19.6% average efficiency resulted in a power output close to 280W. Latest results of the development of the n-MWT technology at cell and module level are discussed in this paper, including a recent direct comparison run between n-MWT and n-Pasha cells and results of n-MWT cells from 140{mu}m thin mono-crystalline wafers, with only very slight loss (1% of Isc) for the thin cells. Also reverse characteristics and effects of reverse bias for extended time at cell and module level are reported, where we find a higher tolerance of MWT modules than tabbed front contact modules for hotspots.

  19. Technical evaluation of Solar Cells, Inc., CdTe module and array at NREL

    Energy Technology Data Exchange (ETDEWEB)

    Kroposki, B.; Strand, T.; Hansen, R. [National Renewable Energy Lab., Golden, CO (United States); Powell, R.; Sasala, R. [Solar Cells, Inc., Toledo, OH (United States)

    1996-05-01

    The Engineering and Technology Validation Team at the National Renewable Energy Laboratory (NREL) conducts in-situ technical evaluations of polycrystalline thin-film photovoltaic (PV) modules and arrays. This paper focuses on the technical evaluation of Solar Cells, Inc., (SCI) cadmium telluride (CdTe) module and array performance by attempting to correlate individual module and array performance. This is done by examining the performance and stability of the modules and array over a period of more than one year. Temperature coefficients for module and array parameters (P{sub max}, V{sub oc}, V{sub max}, I{sub sc}, I{sub max}) are also calculated.

  20. Glucose-ABL1-TOR Signaling Modulates Cell Cycle Tuning to Control Terminal Appressorial Cell Differentiation.

    Science.gov (United States)

    Marroquin-Guzman, Margarita; Sun, Guangchao; Wilson, Richard A

    2017-01-01

    The conserved target of rapamycin (TOR) pathway integrates growth and development with available nutrients, but how cellular glucose controls TOR function and signaling is poorly understood. Here, we provide functional evidence from the devastating rice blast fungus Magnaporthe oryzae that glucose can mediate TOR activity via the product of a novel carbon-responsive gene, ABL1, in order to tune cell cycle progression during infection-related development. Under nutrient-free conditions, wild type (WT) M. oryzae strains form terminal plant-infecting cells (appressoria) at the tips of germ tubes emerging from three-celled spores (conidia). WT appressorial development is accompanied by one round of mitosis followed by autophagic cell death of the conidium. In contrast, Δabl1 mutant strains undergo multiple rounds of accelerated mitosis in elongated germ tubes, produce few appressoria, and are abolished for autophagy. Treating WT spores with glucose or 2-deoxyglucose phenocopied Δabl1. Inactivating TOR in Δabl1 mutants or glucose-treated WT strains restored appressorium formation by promoting mitotic arrest at G1/G0 via an appressorium- and autophagy-inducing cell cycle delay at G2/M. Collectively, this work uncovers a novel glucose-ABL1-TOR signaling axis and shows it engages two metabolic checkpoints in order to modulate cell cycle tuning and mediate terminal appressorial cell differentiation. We thus provide new molecular insights into TOR regulation and cell development in response to glucose.

  1. Principal cell spiking, postsynaptic excitation, and oxygen consumption in the rat cerebellar cortex

    DEFF Research Database (Denmark)

    Thomsen, Kirsten; Piilgaard, Henning; Gjedde, Albert

    2009-01-01

    excitatory synaptic input. Subsequent inhibition of action potential propagation and neurotransmission by blocking voltage-gated Na+-channels eliminated the increases in CMRO2 due to PF stimulation and increased PC spiking, but left a large fraction of CMRO2, i.e., basal CMRO2, intact. In conclusion, whereas......) of postsynaptic excitation and PC spiking during evoked and ongoing neuronal activity in the rat. By inhibiting excitatory synaptic input using ionotropic glutamate receptor blockers, we found that the increase in CMRO2 evoked by parallel fiber (PF) stimulation depended entirely on postsynaptic excitation...... basal CMRO2 in anesthetized animals did not seem to be related to neurosignaling, increases in CMRO2 could be induced by all aspects of neurosignaling. Our findings imply that CMRO2 responses cannot a priori be assigned to specific neuronal activities....

  2. Two-Photon Excitation Microscopy for the Study of Living Cells and Tissues

    Science.gov (United States)

    Benninger, Richard K.P.; Piston, David W.

    2013-01-01

    Two-photon excitation microscopy is an alternative to confocal microscopy that provides advantages for three-dimensional and deep tissue imaging. This unit will describe the basic physical principles behind two-photon excitation and discuss the advantages and limitations of its use in laser-scanning microscopy. The principal advantages of two-photon microscopy are reduced phototoxicity, increased imaging depth, and the ability to initiate highly localized photochemistry in thick samples. Practical considerations for the application of two-photon microscopy will then be discussed, including recent technological advances. This unit will conclude with some recent applications of two-photon microscopy that highlight the key advantages over confocal microscopy and the types of experiments which would benefit most from its application. PMID:23728746

  3. Concentration characteristics and cell arrangement in luminescent concentrator PV modules; Keiko shukogata taiyo denchi module no cell haichi to shuko tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Inamura, A [Science University of Tokyo, Tokyo (Japan); Sakuta, K [Electrotechnical Laboratory, Tsukuba (Japan)

    1997-11-25

    A luminescent concentrator PV module requires no tracking equipment and can use scattered light. A mini PV module was prepared from a luminescent plate of 100times100times3mm, and a single-crystalline PV cell of 100times20mm. Characteristics of various prototype modules with different PV cell areas and cell arrangements were also measured. Four kinds of edge reflecting materials with different reflectances by various white coating were applied to Al sashes for module frames, and each sash was fixed on one edge of the luminescent plate. In experiment, 3 other edges were covered with black tapes to reduce each reflectance to 0%. Although PV module output was affected by reflectance of edges, the output was satisfactory at 90% or more in reflectance showing no difference in output. A concentrating efficiency decreased with an increase in luminescent plate (concentrator) area, while it was improved by cell arrangement with short optical pass length, and cell arrangement hardly affected by edge reflection. 4 refs., 7 figs.

  4. Single-photon cesium Rydberg excitation spectroscopy using 318.6-nm UV laser and room-temperature vapor cell.

    Science.gov (United States)

    Wang, Jieying; Bai, Jiandong; He, Jun; Wang, Junmin

    2017-09-18

    We demonstrate a single-photon Rydberg excitation spectroscopy of cesium (Cs) atoms in a room-temperature vapor cell. Cs atoms are excited directly from 6S 1/2 ground state to nP 3/2 (n = 70 - 100) Rydberg states with a 318.6 nm ultraviolet (UV) laser, and Rydberg excitation spectra are obtained by transmission enhancement of a probe beam resonant to Cs 6S 1/2 , F = 4 - 6P 3/2 , F' = 5 transition as partial population on F = 4 ground state are transferred to Rydberg state. Analysis reveals that the observed spectra are velocity-selective spectroscopy of Rydberg state, from which the amplitude and linewidth influenced by lasers' Rabi frequency have been investigated. Fitting to energies of Cs nP 3/2 (n = 70 -100) states, the determined quantum defect is 3.56671(42). The demodulated spectra can also be employed as frequency references to stabilize the UV laser frequency to specific Cs Rydberg transition.

  5. Mesenchymal Stem Cells Modulate Differentiation of Myeloid Progenitor Cells During Inflammation.

    Science.gov (United States)

    Amouzegar, Afsaneh; Mittal, Sharad K; Sahu, Anuradha; Sahu, Srikant K; Chauhan, Sunil K

    2017-06-01

    Mesenchymal stem cells (MSCs) possess distinct immunomodulatory properties and have tremendous potential for use in therapeutic applications in various inflammatory diseases. MSCs have been shown to regulate pathogenic functions of mature myeloid inflammatory cells, such as macrophages and neutrophils. Intriguingly, the capacity of MSCs to modulate differentiation of myeloid progenitors (MPs) to mature inflammatory cells remains unknown to date. Here, we report the novel finding that MSCs inhibit the expression of differentiation markers on MPs under inflammatory conditions. We demonstrate that the inhibitory effect of MSCs is dependent on direct cell-cell contact and that this intercellular contact is mediated through interaction of CD200 expressed by MSCs and CD200R1 expressed by MPs. Furthermore, using an injury model of sterile inflammation, we show that MSCs promote MP frequencies and suppress infiltration of inflammatory cells in the inflamed tissue. We also find that downregulation of CD200 in MSCs correlates with abrogation of their immunoregulatory function. Collectively, our study provides unequivocal evidence that MSCs inhibit differentiation of MPs in the inflammatory environment via CD200-CD200R1 interaction. Stem Cells 2017;35:1532-1541. © 2017 AlphaMed Press.

  6. Increase in cortical pyramidal cell excitability accompanies depression-like behavior in mice: a transcranial magnetic stimulation study.

    Science.gov (United States)

    Sun, Peng; Wang, Furong; Wang, Li; Zhang, Yu; Yamamoto, Ryo; Sugai, Tokio; Zhang, Qing; Wang, Zhengda; Kato, Nobuo

    2011-11-09

    Clinical evidence suggests that cortical excitability is increased in depressives. We investigated its cellular basis in a mouse model of depression. In a modified version of forced swimming (FS), mice were initially forced to swim for 5 consecutive days and then were treated daily with repetitive transcranial magnetic stimulation (rTMS) or sham treatment for the following 4 weeks without swimming. On day 2 through day 5, the mice manifested depression-like behaviors. The next and last FS was performed 4 weeks later, which revealed a 4 week maintenance of depression-like behavior in the sham mice. In slices from the sham controls, excitability in cingulate cortex pyramidal cells was elevated in terms of membrane potential and frequencies of spikes evoked by current injection. Depolarized resting potential was shown to depend on suppression of large conductance calcium-activated potassium (BK) channels. This BK channel suppression was confirmed by measuring spike width, which depends on BK channels. Chronic rTMS treatment during the 4 week period significantly reduced the depression-like behavior. In slices obtained from the rTMS mice, normal excitability and BK channel activity were recovered. Expression of a scaffold protein Homer1a was reduced by the FS and reversed by rTMS in the cingulate cortex. Similar recovery in the same behavioral, electrophysiological, and biochemical features was observed after chronic imipramine treatment. The present study demonstrated that manifestation and disappearance of depression-like behavior are in parallel with increase and decrease in cortical neuronal excitability in mice and suggested that regulation of BK channels by Homer1a is involved in this parallelism.

  7. Melatonina: modulador de morte celular Melatonin: cell death modulator

    Directory of Open Access Journals (Sweden)

    Cecília da Silva Ferreira

    2010-01-01

    cells are eliminated after activation of a cell death program involving participation of pro-apoptotic molecules (Fas, Fas-L, Bax, caspases 2, 3, 6, 7, 8 and 9. Molecule activation causes typical morphological changes, such as cell shrinkage, loss of adhesion to the extracellular matrix and neighboring cells, chromatin condensation, DNA fragmentation and formation of apoptotic bodies. Anti-apoptotic molecules (Bcl-2, FLIP block the emergence and evolution of these cell changes and prevent cell death. The balance between molecules pro and anti-apoptotic ensures tissue homeostasis. When apoptosis is out of control, it contributes to the emergence of several neoplastic, autoimmune and neurodegenerative diseases. Several inducing and inhibitors of apoptosis agents are recognized as potential weapons in the fight against diseases related to proliferation and cell death disorders among which stand out hormones. Melatonin has been reported as important anti-apoptotic agent in various tissues by reducing cell calcium uptake, modulating expression of anti-oxidants and decreasing pro-apoptotic protein, such as Bax. The knowledge of new agents capable to act on the course pf apoptosis is important and of great value for developing further therapies against many diseases. Thus, the objective of this review was to elucidate the main aspects of cell death by apoptosis and the role of melatonin in this process.

  8. Overview of a HLA-Ig based "Lego-like system" for T cell monitoring, modulation and expansion.

    Science.gov (United States)

    Oelke, Mathias; Schneck, Jonathan P

    2010-07-01

    Recent advances in molecular medicine have shown that soluble MHC-multimers can be valuable tools for both analysis and modulation of antigen-specific immune responses in vitro and in vivo. In this review, we describe the use of dimeric human and mouse major histocompatibility complexes, MHC-Ig, as part of an artificial Antigen-Presenting Cell (aAPC). MHC-Ig-based aAPC and its derivatives represent an exciting new platform technology for measuring and manipulating immune responses in vitro as well as in vivo. This new technology has the potential to help overcome many of the obstacles associated with limitations in current antigen-specific approaches of immunotherapy for the treatment of cancer, infectious diseases and autoimmunity.

  9. Kaempferol modulates the metastasis of human non-small cell lung cancer cells by inhibiting epithelial-mesenchymal transition

    Directory of Open Access Journals (Sweden)

    Meng Hang

    2015-06-01

    Full Text Available The present study was done to determine whether kaempferol, a natural polyphenol of the flavonoid family, affects Epithelial-Mesenchymal Transition (EMT in non-small cell lung cancer cells. Kaempferol not only inhibited cancer cell proliferation and migration in a dose-dependent manner but also modulated the expression of EMT-related proteins E-cadherin and vimentin which are indispensible to cellular motility, invasiveness and metastasis. These results indicate that kaempferol suppresses non-small cell lung cancer migration by modulating the expression of EMT proteins. Therefore, kaempferol may be useful as a potential anticancer agent for non-small cell lung cancer.

  10. Numerical model analysis of thermal performance for a dye-sensitized solar cell module

    International Nuclear Information System (INIS)

    Chen, Shuanghong; Huang, Yang; Weng, Jian; Fan, Xiaqin; Mo, Lie; Pan, Bin; Dai, Songyuan

    2013-01-01

    Temperature is one of the major factors that influence a dye-sensitized solar cell's (DSC's) photovoltaic efficiency. Temperature control is very important when solar cell modules are designed. In the present paper, a numerical model of a DSC module is built for the simulation of the solar cell's temperature. In this model, energy balance and three methods of heat transfer (conduction, convection, and radiation) are taken into account, and the simulation results are consistent with the experimental results. The influence of wind speeds and interfacial thermal resistance on the temperature inside the DSC modules is discussed in detail based on theoretical analysis. (paper)

  11. Musashi1 modulates cell proliferation genes in the medulloblastoma cell line Daoy

    Directory of Open Access Journals (Sweden)

    Hung Jaclyn Y

    2008-09-01

    Full Text Available Abstract Background Musashi1 (Msi1 is an RNA binding protein with a central role during nervous system development and stem cell maintenance. High levels of Msi1 have been reported in several malignancies including brain tumors thereby associating Msi1 and cancer. Methods We used the human medulloblastoma cell line Daoy as model system in this study to knock down the expression of Msi1 and determine the effects upon soft agar growth and neurophere formation. Quantitative RT-PCR was conducted to evaluate the expression of cell proliferation, differentiation and survival genes in Msi1 depleted Daoy cells. Results We observed that MSI1 expression was elevated in Daoy cells cultured as neurospheres compared to those grown as monolayer. These data indicated that Msi1 might be involved in regulating proliferation in cancer cells. Here we show that shRNA mediated Msi1 depletion in Daoy cells notably impaired their ability to form colonies in soft agar and to grow as neurospheres in culture. Moreover, differential expression of a group of Notch, Hedgehog and Wnt pathway related genes including MYCN, FOS, NOTCH2, SMO, CDKN1A, CCND2, CCND1, and DKK1, was also found in the Msi1 knockdown, demonstrating that Msi1 modulated the expression of a subset of cell proliferation, differentiation and survival genes in Daoy. Conclusion Our data suggested that Msi1 may promote cancer cell proliferation and survival as its loss seems to have a detrimental effect in the maintenance of medulloblastoma cancer cells. In this regard, Msi1 might be a positive regulator of tumor progression and a potential target for therapy.

  12. Cryogenic exciter

    Science.gov (United States)

    Bray, James William [Niskayuna, NY; Garces, Luis Jose [Niskayuna, NY

    2012-03-13

    The disclosed technology is a cryogenic static exciter. The cryogenic static exciter is connected to a synchronous electric machine that has a field winding. The synchronous electric machine is cooled via a refrigerator or cryogen like liquid nitrogen. The static exciter is in communication with the field winding and is operating at ambient temperature. The static exciter receives cooling from a refrigerator or cryogen source, which may also service the synchronous machine, to selected areas of the static exciter and the cooling selectively reduces the operating temperature of the selected areas of the static exciter.

  13. Research on fabrication technology for thin film solar cells for practical use. Research on low-cost fabrication technology for large-area modules (CdS/CdTe solar cell modules); Usumaku taiyo denchi seizo gijutsu no jitsuyoka kenkyu. Daimenseki module no tei cost seizo gijutsu (CdTe taiyo denchi module seizo no gijutsu kaihatsu)

    Energy Technology Data Exchange (ETDEWEB)

    Tatsuta, M [New Energy and Industrial Technology Development Organization, Tokyo (Japan)

    1994-12-01

    This paper reports the study results on the fabrication technology of CdS/CdTe solar cell modules in fiscal 1994. (1) On the fabrication technology for high-efficiency large-area solar cells, high-quality CdTe active layer was studied. S content taken in the active layer at sintering of CdTe decreased with an increase in formed CdTe, resulting in improvement of Voc of cells. (2) On the window layer with wide band gap, the solar cell superior in collection efficiency and photoelectric characteristics could be obtained using the newly developed mixed crystal film of Cd(1-x)Zn(x)S. (3) On the forming technology of large-area coating/sintering films, improvement of CdS film quality was studied by pressurized processing of printed CdS films. As a result, improvement of film density and light transmissivity was confirmed. (4) On the leveling process technology of CdTe films, smooth surface films were obtained by experiment using an equipment simultaneously exciting samples in all directions as one of uniform coating methods of films. 7 figs.

  14. M19 modulates skeletal muscle differentiation and insulin secretion in pancreatic β-cells through modulation of respiratory chain activity.

    Directory of Open Access Journals (Sweden)

    Linda Cambier

    Full Text Available Mitochondrial dysfunction due to nuclear or mitochondrial DNA alterations contributes to multiple diseases such as metabolic myopathies, neurodegenerative disorders, diabetes and cancer. Nevertheless, to date, only half of the estimated 1,500 mitochondrial proteins has been identified, and the function of most of these proteins remains to be determined. Here, we characterize the function of M19, a novel mitochondrial nucleoid protein, in muscle and pancreatic β-cells. We have identified a 13-long amino acid sequence located at the N-terminus of M19 that targets the protein to mitochondria. Furthermore, using RNA interference and over-expression strategies, we demonstrate that M19 modulates mitochondrial oxygen consumption and ATP production, and could therefore regulate the respiratory chain activity. In an effort to determine whether M19 could play a role in the regulation of various cell activities, we show that this nucleoid protein, probably through its modulation of mitochondrial ATP production, acts on late muscle differentiation in myogenic C2C12 cells, and plays a permissive role on insulin secretion under basal glucose conditions in INS-1 pancreatic β-cells. Our results are therefore establishing a functional link between a mitochondrial nucleoid protein and the modulation of respiratory chain activities leading to the regulation of major cellular processes such as myogenesis and insulin secretion.

  15. Characterization of cell mismatch in a multi-crystalline silicon photovoltaic module

    International Nuclear Information System (INIS)

    Crozier, J.L.; Dyk, E.E. van; Vorster, F.J.

    2012-01-01

    In this study the causes and effects of cell mismatch were identified in a multi-crystalline silicon photovoltaic module. Different techniques were used to identify the causes of the mismatch, including Electroluminescence (EL) imaging, Infrared (IR) imaging, current–voltage (I–V) characteristics, worst-case cell determination and Large Area Laser Beam Induced Current (LA-LBIC) scans. In EL images the cracked cells, broken fingers and material defects are visible. The presence of poorly contacted cells results in the formation of hot-spots. LA-LBIC line scans give the relative photoresponse of the cells in the module. However, this technique is limited due to the penetration depth of the laser beam. The worst case cell determination compares the I–V curves of the whole module with the I–V curve of the module with one cell covered, allowing the evaluation of the performance of each cell in a series-connected string. These methods allowed detection of the poorly performing cells in the module. Using all these techniques an overall view of the photoresponse in the cells and their performance is obtained.

  16. Characterization of cell mismatch in a multi-crystalline silicon photovoltaic module

    Energy Technology Data Exchange (ETDEWEB)

    Crozier, J.L., E-mail: s207094248@live.nmmu.ac.za [Department of Physics, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa); Dyk, E.E. van; Vorster, F.J. [Department of Physics, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa)

    2012-05-15

    In this study the causes and effects of cell mismatch were identified in a multi-crystalline silicon photovoltaic module. Different techniques were used to identify the causes of the mismatch, including Electroluminescence (EL) imaging, Infrared (IR) imaging, current-voltage (I-V) characteristics, worst-case cell determination and Large Area Laser Beam Induced Current (LA-LBIC) scans. In EL images the cracked cells, broken fingers and material defects are visible. The presence of poorly contacted cells results in the formation of hot-spots. LA-LBIC line scans give the relative photoresponse of the cells in the module. However, this technique is limited due to the penetration depth of the laser beam. The worst case cell determination compares the I-V curves of the whole module with the I-V curve of the module with one cell covered, allowing the evaluation of the performance of each cell in a series-connected string. These methods allowed detection of the poorly performing cells in the module. Using all these techniques an overall view of the photoresponse in the cells and their performance is obtained.

  17. Morphological modulation of human fibrosarcoma HT-1080 cells by hydroxybenzoate compounds during apoptosis

    Directory of Open Access Journals (Sweden)

    Jassem G Mahdi

    2015-10-01

    Full Text Available Hydroxybenzoate (HB compounds have shown to modulate the morphology in human fibrosarcoma HT-1080 cells. The changes in HT-1080 cells showed marker signs of apoptosis, which included the condensation of nucleus, cell round, blebbing and the formation of apoptotic bodies. The different stages of apoptosis were assessed microscopically using different staining and immunohistochemical techniques, as well as scanning electron microscopy. In addition, HB compounds increased the expression of caspase-3, which is closely associated with the development of the modulation in HT-1080 cells that are undergoing the programmed cell death. Both acetyl salicylic acid (ASA and HBZn compounds were dose and treatment duration dependent.

  18. Cytotoxicity of cancer HeLa cells sensitivity to normal MCF10A cells in cultivations with cell culture medium treated by microwave-excited atmospheric pressure plasmas

    Science.gov (United States)

    Takahashi, Yohei; Taki, Yusuke; Takeda, Keigo; Hashizume, Hiroshi; Tanaka, Hiromasa; Ishikawa, Kenji; Hori, Masaru

    2018-03-01

    Cytotoxic effects of human epithelial carcinoma HeLa cells sensitivity to human mammary epithelial MCF10A cells appeared in incubation with the plasma-activated medium (PAM), where the cell culture media were irradiated with the hollow-shaped contact of a continuously discharged plasma that was sustained by application of a microwave power under Ar gas flow at atmospheric pressure. The discharged plasma had an electron density of 7  ×  1014 cm-3. As the nozzle exit to the plasma source was a distance of 5 mm to the medium, concentrations of 180 µM for H2O2 and 77 µM for NO2- were generated in the PAM for 30 s irradiation, resulting in the control of irradiation periods for aqueous H2O2 with a generation rate of 6.0 µM s-1, and nitrite ion (NO2- ) with a rate of 2.2 µM s-1. Effective concentrations of H2O2 and NO2- for the antitumor effects were revealed in the microwave-excited PAM, with consideration of the complicated reactions at the plasma-liquid interfaces.

  19. Regulatory B cells: an exciting target for future therapeutics in transplantation

    Directory of Open Access Journals (Sweden)

    Alexandre eNouël

    2014-01-01

    Full Text Available Transplantation is the preferred treatment for most end-stage solid organ diseases. Despite potent immunosuppressive agents, chronic rejection remains a real problem in transplantation. For many years, the predominant immunological focus of research into transplant rejection has been T cells. The pillar of immunotherapy in clinical practice is T cell-directed, which efficiently prevents acute T cell-mediated allograft rejection. However, the root of late allograft failure is chronic rejection and the humoral arm of the immune response now emerges as an important factor in transplantation. Thus, the potential effects of Abs and B cell infiltrates on transplants have cast B cells as major actors in late graft rejection. Consequently, a number of recent drugs target either B cells or plasma cells. However, immunotherapies, such as the anti-CD20 B cell-depleting Ab, can generate deleterious effects on the transplant, likely due to the deletion of beneficial population. The positive contribution of regulatory B (Breg cells -or B10 cells- has been reported in the case of transplantation, mainly in mice models and highlights the primordial role that some populations of B cells can play in graft tolerance. Yet, this regulatory aspect remains poorly characterized in clinical transplantation. Thus, total B cell depletion treatments should be avoided and novel approaches should be considered that manipulate the different B cell subsets. This article provides an overview of the current knowledge on the link between Breg cells and grafts, and reports a number of data advising Breg cells as a new target for future therapeutic approaches.

  20. CD4+CD25+ regulatory T cells control CD8+ T-cell effector differentiation by modulating IL-2 homeostasis

    Science.gov (United States)

    McNally, Alice; Hill, Geoffrey R.; Sparwasser, Tim; Thomas, Ranjeny; Steptoe, Raymond J.

    2011-01-01

    CD4+CD25+ regulatory T cells (Treg) play a crucial role in the regulation of immune responses. Although many mechanisms of Treg suppression in vitro have been described, the mechanisms by which Treg modulate CD8+ T cell differentiation and effector function in vivo are more poorly defined. It has been proposed, in many instances, that modulation of cytokine homeostasis could be an important mechanism by which Treg regulate adaptive immunity; however, direct experimental evidence is sparse. Here we demonstrate that CD4+CD25+ Treg, by critically regulating IL-2 homeostasis, modulate CD8+ T-cell effector differentiation. Expansion and effector differentiation of CD8+ T cells is promoted by autocrine IL-2 but, by competing for IL-2, Treg limit CD8+ effector differentiation. Furthermore, a regulatory loop exists between Treg and CD8+ effector T cells, where IL-2 produced during CD8+ T-cell effector differentiation promotes Treg expansion. PMID:21502514

  1. 77 FR 14732 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

    Science.gov (United States)

    2012-03-13

    ... Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's Republic of China: Postponement of... of an antidumping duty investigation of crystalline silicon photovoltaic cells, whether or not... currently due no later than March 27, 2012. \\1\\ See Crystalline Silicon Photovoltaic Cells, Whether or Not...

  2. Can Cell to Cell Thermal Runaway Propagation be Prevented in a Li-ion Battery Module?

    Science.gov (United States)

    Jeevarajan, Judith; Lopez, Carlos; Orieukwu, Josephat

    2014-01-01

    Increasing cell spacing decreased adjacent cell damage center dotElectrically connected adjacent cells drained more than physically adjacent cells center dotRadiant barrier prevents propagation when fully installed between BP cells center dotBP cells vent rapidly and expel contents at 100% SOC -Slower vent with flame/smoke at 50% -Thermal runaway event typically occurs at 160 degC center dotLG cells vent but do not expel contents -Thermal runaway event typically occurs at 200 degC center dotSKC LFP modules did not propagate; fuses on negative terminal of cell may provide a benefit in reducing cell to cell damage propagation. New requirement in NASA-Battery Safety Requirements document: JSC 20793 Rev C 5.1.5.1 Requirements - Thermal Runaway Propagation a. For battery designs greater than a 80-Wh energy employing high specific energy cells (greater than 80 watt-hours/kg, for example, lithium-ion chemistries) with catastrophic failure modes, the battery shall be evaluated to ascertain the severity of a worst-case single-cell thermal runaway event and the propensity of the design to demonstrate cell-to-cell propagation in the intended application and environment. NASA has traditionally addressed the threat of thermal runaway incidents in its battery deployments through comprehensive prevention protocols. This prevention-centered approach has included extensive screening for manufacturing defects, as well as robust battery management controls that prevent abuse-induced runaway even in the face of multiple system failures. This focused strategy has made the likelihood of occurrence of such an event highly improbable. b. The evaluation shall include all necessary analysis and test to quantify the severity (consequence) of the event in the intended application and environment as well as to identify design modifications to the battery or the system that could appreciably reduce that severity. In addition to prevention protocols, programs developing battery designs with

  3. Functional microarray analysis suggests repressed cell-cell signaling and cell survival-related modules inhibit progression of head and neck squamous cell carcinoma

    Directory of Open Access Journals (Sweden)

    Soares Fernando A

    2011-04-01

    Full Text Available Abstract Background Cancer shows a great diversity in its clinical behavior which cannot be easily predicted using the currently available clinical or pathological markers. The identification of pathways associated with lymph node metastasis (N+ and recurrent head and neck squamous cell carcinoma (HNSCC may increase our understanding of the complex biology of this disease. Methods Tumor samples were obtained from untreated HNSCC patients undergoing surgery. Patients were classified according to pathologic lymph node status (positive or negative or tumor recurrence (recurrent or non-recurrent tumor after treatment (surgery with neck dissection followed by radiotherapy. Using microarray gene expression, we screened tumor samples according to modules comprised by genes in the same pathway or functional category. Results The most frequent alterations were the repression of modules in negative lymph node (N0 and in non-recurrent tumors rather than induction of modules in N+ or in recurrent tumors. N0 tumors showed repression of modules that contain cell survival genes and in non-recurrent tumors cell-cell signaling and extracellular region modules were repressed. Conclusions The repression of modules that contain cell survival genes in N0 tumors reinforces the important role that apoptosis plays in the regulation of metastasis. In addition, because tumor samples used here were not microdissected, tumor gene expression data are represented together with the stroma, which may reveal signaling between the microenvironment and tumor cells. For instance, in non-recurrent tumors, extracellular region module was repressed, indicating that the stroma and tumor cells may have fewer interactions, which disable metastasis development. Finally, the genes highlighted in our analysis can be implicated in more than one pathway or characteristic, suggesting that therapeutic approaches to prevent tumor progression should target more than one gene or pathway

  4. Water-Soluble Triarylborane Chromophores for One- and Two-Photon Excited Fluorescence Imaging of Mitochondria in Cells.

    Science.gov (United States)

    Griesbeck, Stefanie; Zhang, Zuolun; Gutmann, Marcus; Lühmann, Tessa; Edkins, Robert M; Clermont, Guillaume; Lazar, Adina N; Haehnel, Martin; Edkins, Katharina; Eichhorn, Antonius; Blanchard-Desce, Mireille; Meinel, Lorenz; Marder, Todd B

    2016-10-04

    Three water-soluble tetracationic quadrupolar chromophores comprising two three-coordinate boron π-acceptor groups bridged by thiophene-containing moieties were synthesised for biological imaging applications. Compound 3 containing the bulkier 5-(3,5-Me2 C6 H2 )-2,2'-(C4 H2 S)2 -5'-(3,5-Me2 C6 H2 ) bridge is stable over a long period of time, exhibits a high fluorescence quantum yield and strong one- and two-photon absorption (TPA), and has a TPA cross section of 268 GM at 800 nm in water. Confocal laser scanning fluorescence microscopy studies in live cells indicated localisation of the chromophore at the mitochondria; moreover, cytotoxicity measurements proved biocompatibility. Thus, chromophore 3 has excellent potential for one- and two-photon-excited fluorescence imaging of mitochondrial function in cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Modulated surface textures for enhanced scattering in thin-film silicon solar cells

    NARCIS (Netherlands)

    Isabella, O.; Battaglia, C.; Ballif, C.; Zeman, M.

    2012-01-01

    Nano-scale randomly textured front transparent oxides are superposed on micro-scale etched glass substrates to form modulated surface textures. The resulting enhanced light scattering is implemented in single and double junction thin-film silicon solar cells.

  6. Non-synaptic signaling from cerebellar climbing fibers modulates Golgi cell activity.

    Science.gov (United States)

    Nietz, Angela K; Vaden, Jada H; Coddington, Luke T; Overstreet-Wadiche, Linda; Wadiche, Jacques I

    2017-10-13

    Golgi cells are the principal inhibitory neurons at the input stage of the cerebellum, providing feedforward and feedback inhibition through mossy fiber and parallel fiber synapses. In vivo studies have shown that Golgi cell activity is regulated by climbing fiber stimulation, yet there is little functional or anatomical evidence for synapses between climbing fibers and Golgi cells. Here, we show that glutamate released from climbing fibers activates ionotropic and metabotropic receptors on Golgi cells through spillover-mediated transmission. The interplay of excitatory and inhibitory conductances provides flexible control over Golgi cell spiking, allowing either excitation or a biphasic sequence of excitation and inhibition following single climbing fiber stimulation. Together with prior studies of spillover transmission to molecular layer interneurons, these results reveal that climbing fibers exert control over inhibition at both the input and output layers of the cerebellar cortex.

  7. Low Doses of Curcuma longa Modulates Cell Migration and Cell-Cell Adhesion.

    Science.gov (United States)

    de Campos, Paloma Santos; Matte, Bibiana Franzen; Diel, Leonardo Francisco; Jesus, Luciano Henrique; Bernardi, Lisiane; Alves, Alessandro Menna; Rados, Pantelis Varvaki; Lamers, Marcelo Lazzaron

    2017-09-01

    Cell invasion and metastasis are involved in clinical failures in cancer treatment, and both events require the acquisition of a migratory behavior by tumor cells. Curcumin is a promising natural product with anti-proliferative activity, but its effects on cell migration are still unclear. We evaluated the effects of curcumin on the proliferation, apoptosis, migration, and cell-cell adhesion of keratinocyte, oral squamous cell carcinoma (OSCC), and fibroblast cell lines, as well as in a xenograft model of OSCC. Curcumin (2 μM) decreased cell proliferation in cell lines with mesenchymal characteristics, while cell death was detected only at 50 μM. We observed that highly migratory cells showed a decrease on migration speed and directionality when treated with 2 or 5 μM of curcumin (50% and 40%, respectively, p curcumin dose dependently decreased cell-cell adhesion, especially on tumor-derived spheroids. Also, in a xenograft model with patient-derived OSCC cells, the administration of curcumin decreased tumor growth and aggressiveness when compared with untreated tumors, indicating the potential antitumor effect in oral cancer. These results suggest that lower doses of curcumin can influence several steps involved in tumorigenesis, including migration properties, suggesting a possible use in cancer therapy. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  8. Design of robotic cells based on relative handling modules with use of SolidWorks system

    Science.gov (United States)

    Gaponenko, E. V.; Anciferov, S. I.

    2018-05-01

    The article presents a diagramed engineering solution for a robotic cell with six degrees of freedom for machining of complex details, consisting of the base with a tool installation module and a detail machining module made as parallel structure mechanisms. The output links of the detail machining module and the tool installation module can move along X-Y-Z coordinate axes each. A 3D-model of the complex is designed in the SolidWorks system. It will be used further for carrying out engineering calculations and mathematical analysis and obtaining all required documentation.

  9. Excited state and charge-carrier dynamics in perovskite solar cell materials

    Science.gov (United States)

    Ponseca, Carlito S., Jr.; Tian, Yuxi; Sundström, Villy; Scheblykin, Ivan G.

    2016-02-01

    Organo-metal halide perovskites (OMHPs) have attracted enormous interest in recent years as materials for application in optoelectronics and solar energy conversion. These hybrid semiconductors seem to have the potential to challenge traditional silicon technology. In this review we will give an account of the recent development in the understanding of the fundamental light-induced processes in OMHPs from charge-photo generation, migration of charge carries through the materials and finally their recombination. Our and other literature reports on time-resolved conductivity, transient absorption and photoluminescence properties are used to paint a picture of how we currently see the fundamental excited state and charge-carrier dynamics. We will also show that there is still no fully coherent picture of the processes in OMHPs and we will indicate the problems to be solved by future research.

  10. Excited state and charge-carrier dynamics in perovskite solar cell materials

    International Nuclear Information System (INIS)

    Ponseca, Carlito S Jr; Tian, Yuxi; Sundström, Villy; Scheblykin, Ivan G

    2016-01-01

    Organo-metal halide perovskites (OMHPs) have attracted enormous interest in recent years as materials for application in optoelectronics and solar energy conversion. These hybrid semiconductors seem to have the potential to challenge traditional silicon technology. In this review we will give an account of the recent development in the understanding of the fundamental light-induced processes in OMHPs from charge-photo generation, migration of charge carries through the materials and finally their recombination. Our and other literature reports on time-resolved conductivity, transient absorption and photoluminescence properties are used to paint a picture of how we currently see the fundamental excited state and charge-carrier dynamics. We will also show that there is still no fully coherent picture of the processes in OMHPs and we will indicate the problems to be solved by future research. (topical review)

  11. Organic solar cell modules for specific applications-From energy autonomous systems to large area photovoltaics

    International Nuclear Information System (INIS)

    Niggemann, M.; Zimmermann, B.; Haschke, J.; Glatthaar, M.; Gombert, A.

    2008-01-01

    We report on the development of two types of organic solar cell modules one for energy autonomous systems and one for large area energy harvesting. The first requires a specific tailoring of the solar cell geometry and cell interconnection in order to power an energy autonomous system under its specific operating conditions. We present an organic solar cell module with 22 interconnected solar cells. A power conversion efficiency of 2% under solar illumination has been reached on the active area of 46.2 cm 2 . A voltage of 4 V at the maximum power point has been obtained under indoor illumination conditions. Micro contact printing of a self assembling monolayer was employed for the patterning of the polymer anode. Large area photovoltaic modules have to meet the requirements on efficiency, lifetime and costs simultaneously. To minimize the production costs, a suitable concept for efficient reel-to-reel production of large area modules is needed. A major contribution to reduce the costs is the substitution of the commonly used indium tin oxide electrode by a cheap material. We present the state of the art of the anode wrap through concept as a reel-to-reel suited module concept and show comparative calculations of the module interconnection of the wrap through concept and the standard ITO-based cell architecture. As a result, the calculated overall module efficiency of the anode wrap through module exceeds the overall efficiency of modules based on ITO on glass (sheet resistance 15 Ω/square) and on foils (sheet resistance 60 Ω/square)

  12. Self-glycolipids modulate dendritic cells changing the cytokine profiles of committed autoreactive T cells.

    Directory of Open Access Journals (Sweden)

    Karsten Buschard

    Full Text Available The impact of glycolipids of non-mammalian origin on autoimmune inflammation has become widely recognized. Here we report that the naturally occurring mammalian glycolipids, sulfatide and β-GalCer, affect the differentiation and the quality of antigen presentation by monocyte-derived dendritic cells (DCs. In response to sulfatide and β-GalCer, monocytes develop into immature DCs with higher expression of HLA-DR and CD86 but lower expression of CD80, CD40 and CD1a and lower production of IL-12 compared to non-modulated DCs. Self-glycolipid-modulated DCs responded to lipopolysaccharide (LPS by changing phenotype but preserved low IL-12 production. Sulfatide, in particular, reduced the capacity of DCs to stimulate autoreactive Glutamic Acid Decarboxylase (GAD65 - specific T cell response and promoted IL-10 production by the GAD65-specific clone. Since sulfatide and β-GalCer induced toll-like receptor (TLR-mediated signaling, we hypothesize that self-glycolipids deliver a (tolerogenic polarizing signal to differentiating DCs, facilitating the maintenance of self-tolerance under proinflammatory conditions.

  13. Coulomb excitation

    International Nuclear Information System (INIS)

    McGowan, F.K.; Stelson, P.H.

    1974-01-01

    The theory of Coulomb excitation and a brief review of pertinent treatments of the Coulomb excitation process that are useful for the analysis of experiments are given. Examples demonstrating the scope of nuclear structure information obtainable from gamma spectroscopy are presented. Direct Elambda excitation of 232 Th is discussed in terms of the one phonon octupole vibrational spectrum. B(MI) reduced transition probabilities resulting from Coulomb excitation of odd-A deformed nuclei with heavy ions are presented as a test of the rotational model. The use of gamma ray coincidence and particle-gamma coincidence as tools for investigating Coulomb excitation is discussed. (U.S.)

  14. The effect of partial shading on dye-sensitized solar cell module characteristics

    International Nuclear Information System (INIS)

    Pan, Bin; Weng, Jian; Chen, Shuanghong; Huang, Yang; Dai, Songyuan

    2014-01-01

    The dye-sensitized solar cell (DSC) is a kind of novel solar cell with prospects for building integrated photovoltaic applications. In some situations, a DSC module may work under partial shading conditions, and subsequently the module temperature and I–V characteristics change. In this work, the effect of partial shading on DSC module characteristics is experimentally studied and the temperature and electric output of the partially shaded DSC module are measured. The variations of module temperature and output performance are analyzed under short circuit conditions and a normal operating mode of charging battery. Furthermore, the stability of the partially shaded DSC module is also evaluated. It is found that the temperature rise of the DSC module caused by partial shading is slower and much smaller than the silicon solar cell, and the characteristics of the single DSC that suffered from short-term shading remain stable. For a DSC module operating in charging mode, the maximum power point and working point change when a shadow appears. (paper)

  15. The histone deacetylase inhibitor Trichostatin A modulates CD4+ T cell responses

    DEFF Research Database (Denmark)

    Moreira, José Manuel Alfonso; Scheipers, Peter; Sørensen, Poul

    2003-01-01

    though several genes modulated by HDAC inhibition have been identified, those genes clearly responsible for the biological effects of these drugs have remained elusive. We investigated the pharmacological effect of the HDACI and potential anti-cancer agent Trichostatin A (TSA) on primary T cells.......Histone deacetylase inhibitors (HDACIs) induce hyperacetylation of core histones modulating chromatin structure and affecting gene expression. These compounds are also able to induce growth arrest, cell differentiation, and apoptotic cell death of tumor cells in vitro as well as in vivo. Even...

  16. Some tests of flat plate photovoltaic module cell temperatures in simulated field conditions

    Science.gov (United States)

    Griffith, J. S.; Rathod, M. S.; Paslaski, J.

    1981-01-01

    The nominal operating cell temperature (NOCT) of solar photovoltaic (PV) modules is an important characteristic. Typically, the power output of a PV module decreases 0.5% per deg C rise in cell temperature. Several tests were run with artificial sun and wind to study the parametric dependencies of cell temperature on wind speed and direction and ambient temperature. It was found that the cell temperature is extremely sensitive to wind speed, moderately so to wind direction and rather insensitive to ambient temperature. Several suggestions are made to obtain data more typical of field conditions.

  17. Modulation of Ocular Inflammation by Mesenchymal Stem Cells

    Science.gov (United States)

    2017-03-01

    mature myeloid cells in 64 host defense and resolution of inflammation, excessive innate immune response can have 65 deleterious effects on tissue...that MSCs can regulate 69 functions of mature innate immune cells , including polarization of inflammatory macrophages 70 into an anti-inflammatory... cells 191 As immune cells are primarily developed in lymphoid organs, single cell suspensions from bone 192 marrow, spleen, and submandibular lymph

  18. Characterization of altered intrinsic excitability in hippocampal CA1 pyramidal cells of the Aβ-overproducing PDAPP mouse☆

    Science.gov (United States)

    Kerrigan, T.L.; Brown, J.T.; Randall, A.D.

    2014-01-01

    Transgenic mice that accumulate Aβ peptides in the CNS are commonly used to interrogate functional consequences of Alzheimer's disease-associated amyloidopathy. In addition to changes to synaptic function, there is also growing evidence that changes to intrinsic excitability of neurones can arise in these models of amyloidopathy. Furthermore, some of these alterations to intrinsic properties may occur relatively early within the age-related progression of experimental amyloidopathy. Here we report a detailed comparison between the intrinsic excitability properties of hippocampal CA1 pyramidal neurones in wild-type (WT) and PDAPP mice. The latter is a well-established model of Aβ accumulation which expresses human APP harbouring the Indiana (V717F) mutation. At the age employed in this study (9–10 months) CNS Abeta was elevated in PDAPP mice but significant plaque pathology was absent. PDAPP mice exhibited no differences in subthreshold intrinsic properties including resting potential, input resistance, membrane time constant and sag. When CA1 cells of PDAPP mice were given depolarizing stimuli of various amplitudes they initially fired at a higher frequency than WT cells. Commensurate with this, PDAPP cells exhibited a larger fast afterdepolarizing potential. PDAPP mice had narrower spikes but action potential threshold, rate of rise and peak were not different. Thus not all changes seen in our previous studies of amyloidopathy models were present in PDAPP mice; however, narrower spikes, larger ADPs and the propensity to fire at higher frequencies were consistent with our prior work and thus may represent robust, cross-model, indices of amyloidopathy. This article is part of a Special Issue entitled ‘Neurodevelopment Disorder’. PMID:24055500

  19. PVSIM{copyright}: A simulation program for photovoltaic cells, modules, and arrays

    Energy Technology Data Exchange (ETDEWEB)

    King, D.L.; Dudley, J.K.; Boyson, W.E.

    1996-06-01

    An electrical simulation model for photovoltaic cells, modules, and arrays has been developed that will be useful to a wide range of analysts in the photovoltaic industry. The Microsoft{reg_sign} Windows{trademark} based program can be used to analyze individual cells, to analyze the effects of cell mismatch or reverse bias(`hot spot`) heating in modules and to analyze the performance of large arrays of modules including bypass and blocking diodes. User defined statistical variance can be applied to the fundamental parameters used to simulate the cells and diodes. The model is most appropriate for cells that can be accurately modeled using a two-diode equivalent circuit. This paper describes the simulation program and illustrates its versatility with examples.

  20. Solar excitation of CdS/Cu2S photovoltaic cells

    Science.gov (United States)

    Boer, K. W.

    1976-01-01

    Solar radiation of five typical clear weather days and under a variety of conditions is used to determine the spectral distribution of the photonflux at different planes of a CdS/Cu2S solar cell. The fractions of reflected and absorbed flux are determined at each of the relevant interfaces and active volume elements of the solar cell. The density of absorbed photons is given in respect to spectral and spatial distribution. The variance of the obtained distribution, with changes in insolation and absorption spectra of the active solar cell layers, is indicated. A catalog of typical examples is given in the appendix.

  1. A glimpse into the interactions of cells in a microenvironment: the modulation of T cells by mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    Choi J

    2014-05-01

    Full Text Available Jonghoon Choi,1,2 Mintai P Hwang,3 Jong-Wook Lee,3 Kwan Hyi Lee3,41Institute of Research Strategy and Development (IRSD, Seoul, Republic of Korea; 2Department of Bionano Engineering, Hanyang University, Ansan, Republic of Korea; 3Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology, Seoul, Republic of Korea; 4Department of Biomedical Engineering, University of Science and Technology, Seoul, Republic of KoreaAbstract: Mesenchymal stem cells (MSCs have been thought to hold potential as a mode of therapy for immuno-related pathologies, particularly for autoimmune diseases. Despite their potential, the interaction between MSCs and T cells, key players in the pathophysiology of autoimmune diseases, is not yet well understood, thereby preventing further clinical progress. A major obstacle is the highly heterogeneous nature of MSCs in vitro. Unfortunately, bulk assays do not provide information with regard to cell–cell contributions that may play a critical role in the overall cellular response. To address these issues, we investigated the interaction between smaller subsets of MSCs and CD4 T cells in a microwell array. We demonstrate that MSCs appear capable of modulating the T cell proliferation rate in response to persistent cell–cell interactions, and we anticipate the use of our microwell array in the classification of subpopulations within MSCs, ultimately leading to specific therapeutic interventions.Keywords: mesenchymal stem cell, T cell, microwell array

  2. Dynamic nano-imaging of label-free living cells using electron beam excitation-assisted optical microscope

    Science.gov (United States)

    Fukuta, Masahiro; Kanamori, Satoshi; Furukawa, Taichi; Nawa, Yasunori; Inami, Wataru; Lin, Sheng; Kawata, Yoshimasa; Terakawa, Susumu

    2015-01-01

    Optical microscopes are effective tools for cellular function analysis because biological cells can be observed non-destructively and non-invasively in the living state in either water or atmosphere condition. Label-free optical imaging technique such as phase-contrast microscopy has been analysed many cellular functions, and it is essential technology for bioscience field. However, the diffraction limit of light makes it is difficult to image nano-structures in a label-free living cell, for example the endoplasmic reticulum, the Golgi body and the localization of proteins. Here we demonstrate the dynamic imaging of a label-free cell with high spatial resolution by using an electron beam excitation-assisted optical (EXA) microscope. We observed the dynamic movement of the nucleus and nano-scale granules in living cells with better than 100 nm spatial resolution and a signal-to-noise ratio (SNR) around 10. Our results contribute to the development of cellular function analysis and open up new bioscience applications. PMID:26525841

  3. Dynamic nano-imaging of label-free living cells using electron beam excitation-assisted optical microscope.

    Science.gov (United States)

    Fukuta, Masahiro; Kanamori, Satoshi; Furukawa, Taichi; Nawa, Yasunori; Inami, Wataru; Lin, Sheng; Kawata, Yoshimasa; Terakawa, Susumu

    2015-11-03

    Optical microscopes are effective tools for cellular function analysis because biological cells can be observed non-destructively and non-invasively in the living state in either water or atmosphere condition. Label-free optical imaging technique such as phase-contrast microscopy has been analysed many cellular functions, and it is essential technology for bioscience field. However, the diffraction limit of light makes it is difficult to image nano-structures in a label-free living cell, for example the endoplasmic reticulum, the Golgi body and the localization of proteins. Here we demonstrate the dynamic imaging of a label-free cell with high spatial resolution by using an electron beam excitation-assisted optical (EXA) microscope. We observed the dynamic movement of the nucleus and nano-scale granules in living cells with better than 100 nm spatial resolution and a signal-to-noise ratio (SNR) around 10. Our results contribute to the development of cellular function analysis and open up new bioscience applications.

  4. Modulation of hemopoiesis by novel stromal cell factors

    International Nuclear Information System (INIS)

    Zipori, D.

    1988-01-01

    The microenvironment of the bone marrow in mammals is a crucial site for the maintenance of a pluripotent hemopoietic stem cell pool. Our previous studies and present findings support the notion that both this function and the fine architecture of hemopoietic organs, i.e., the spatial arrangement of blood cells within the tissue, may be directed by stromal cells. Despite the ability of cloned stromal cells to support prolonged hempoiesis and maintenance in vitro of stem cells with high radioprotective ability, they are a poor source of colony stimulating factor-1 (CSF-1) and do not secrete the other species of CSF. Furthermore, cultured stromal cells antagonize the activity of CSF. It is proposed that stromal cell factors distinct from known CSFs, regulate stem cell renewal. An additional phenomenon that is mediated by stromal cells and can not be attributed to CSF, is their ability to specifically inhibit the accumulation of cells of particular lineage and stage of differentiation. A glycoprotein that inhibits the growth of plasmacytomas but not a variety of other cell types was isolated from one type of cloned stromal cells. Such specific inhibitors may account for the control of cell localization in the hemopoietic system

  5. Modulation of GLO1 Expression Affects Malignant Properties of Cells

    Directory of Open Access Journals (Sweden)

    Antje Hutschenreuther

    2016-12-01

    Full Text Available The energy metabolism of most tumor cells relies on aerobic glycolysis (Warburg effect characterized by an increased glycolytic flux that is accompanied by the increased formation of the cytotoxic metabolite methylglyoxal (MGO. Consequently, the rate of detoxification of this reactive glycolytic byproduct needs to be increased in order to prevent deleterious effects to the cells. This is brought about by an increased expression of glyoxalase 1 (GLO1 that is the rate-limiting enzyme of the MGO-detoxifying glyoxalase system. Here, we overexpressed GLO1 in HEK 293 cells and silenced it in MCF-7 cells using shRNA. Tumor-related properties of wild type and transformed cells were compared and key glycolytic enzyme activities assessed. Furthermore, the cells were subjected to hypoxic conditions to analyze the impact on cell proliferation and enzyme activities. Our results demonstrate that knockdown of GLO1 in the cancer cells significantly reduced tumor-associated properties such as migration and proliferation, whereas no functional alterations where found by overexpression of GLO1 in HEK 293 cells. In contrast, hypoxia caused inhibition of cell growth of all cells except of those overexpressing GLO1. Altogether, we conclude that GLO1 on one hand is crucial to maintaining tumor characteristics of malignant cells, and, on the other hand, supports malignant transformation of cells in a hypoxic environment when overexpressed.

  6. Cannabinoids as modulators of cancer cell viability, neuronal differentiation, and embryonal development

    OpenAIRE

    Gustafsson, Sofia

    2012-01-01

    Cannabinoids (CBs) are compounds that activate the CB1 and CB2 receptors. CB receptors mediate many different physiological functions, and cannabinoids have been reported to decrease tumor cell viability, proliferation, migration, as well as to modulate metastasis. In this thesis, the effects of cannabinoids on human colorectal carcinoma Caco-2 cells (Paper I) and mouse P19 embryonal carcinoma (EC) cells (Paper III) were studied.  In both cell lines, the compounds examined produced a concentr...

  7. Mapping the Local Organization of Cell Membranes Using Excitation-Polarization-Resolved Confocal Fluorescence Microscopy

    OpenAIRE

    Kress, Alla; Wang, Xiao; Ranchon, Hubert; Savatier, Julien; Rigneault, Hervé; Ferrand, Patrick; Brasselet, Sophie

    2013-01-01

    International audience; Fluorescence anisotropy and linear dichroism imaging have been widely used for imaging biomolecular orientational distributions in protein aggregates, fibrillar structures of cells, and cell membranes. However, these techniques do not give access to complete orientational order information in a whole image, because their use is limited to parts of the sample where the average orientation of molecules is known a priori. Fluorescence anisotropy is also highly sensitive t...

  8. Solar cell modules with improved backskin and methods for forming same

    Science.gov (United States)

    Hanoka, Jack I.

    1998-04-21

    A laminated solar cell module with a backskin layer that reduces the materials and labor required during the manufacturing process. The solar cell module includes a rigid front support layer formed of light transmitting material having first and second surfaces. A transparent encapsulant layer has a first surface disposed adjacent the second surface of the front support layer. A plurality of interconnected solar cells have a first surface disposed adjacent a second surface of the transparent encapsulant layer. The backskin layer is formed of a thermoplastic olefin, which includes first ionomer, a second ionomer, glass fiber, and carbon black. A first surface of the backskin layer is disposed adjacent a second surface of the interconnected solar cells. The transparent encapsulant layer and the backskin layer, in combination, encapsulate the interconnected solar cells. An end portion of the backskin layer can be wrapped around the edge of the module for contacting the first surface of the front support layer to form an edge seal. A laminated solar cell module with a backskin layer that reduces the materials and labor required during the manufacturing process. The solar cell module includes a rigid front support layer formed of light transmitting material having first and second surfaces. A transparent encapsulant layer has a first surface disposed adjacent the second surface of the front support layer. A plurality of interconnected solar cells have a first surface disposed adjacent a second surface of the transparent encapsulant layer. The backskin layer is formed of a thermoplastic olefin, which includes first ionomer, a second ionomer, glass fiber, and carbon black. A first surface of the backskin layer is disposed adjacent a second surface of the interconnected solar cells. The transparent encapsulant layer and the backskin layer, in combination, encapsulate the interconnected solar cells. An end portion of the backskin layer can be wrapped around the edge of the

  9. Mesothelioma tumor cells modulate dendritic cell lipid content, phenotype and function.

    Directory of Open Access Journals (Sweden)

    Joanne K Gardner

    Full Text Available Dendritic cells (DCs play an important role in the generation of anti-cancer immune responses, however there is evidence that DCs in cancer patients are dysfunctional. Lipid accumulation driven by tumor-derived factors has recently been shown to contribute to DC dysfunction in several human cancers, but has not yet been examined in mesothelioma. This study investigated if mesothelioma tumor cells and/or their secreted factors promote increases in DC lipid content and modulate DC function. Human monocyte-derived DCs (MoDCs were exposed to human mesothelioma tumor cells and tumor-derived factors in the presence or absence of lipoproteins. The data showed that immature MoDCs exposed to mesothelioma cells or factors contained increased lipid levels relative to control DCs. Lipid accumulation was associated with reduced antigen processing ability (measured using a DQ OVA assay, upregulation of the co-stimulatory molecule, CD86, and production of the tolerogenic cytokine, IL-10. Increases in DC lipid content were further enhanced by co-exposure to mesothelioma-derived factors and triglyceride-rich lipoproteins, but not low-density lipoproteins. In vivo studies using a murine mesothelioma model showed that the lipid content of tumor-infiltrating CD4+ CD8α- DCs, CD4- CD8α- DCs DCs and plasmacytoid DCs increased with tumor progression. Moreover, increasing tumor burden was associated with reduced proliferation of tumor-antigen-specific CD8+ T cells in tumor-draining lymph nodes. This study shows that mesothelioma promotes DC lipid acquisition, which is associated with altered activation status and reduced capacity to process and present antigens, which may impair the ability of DCs to generate effective anti mesothelioma T cell responses.

  10. GAS5 modulated autophagy is a mechanism modulating cisplatin sensitivity in NSCLC cells.

    Science.gov (United States)

    Zhang, N; Yang, G-Q; Shao, X-M; Wei, L

    2016-06-01

    In this study, we investigated the association between lncRNA GAS5 and cisplatin (DDP) resistance in NSCLC and further studied the regulative effect of GAS5 on autophagy and DDP resistance. GAS5 expression in cancerous and adjacent normal tissues from 15 NSCLC patients received neoadjuvant chemotherapy and the following surgery were measured using qRT-PCR analysis. GAS5 gain-and-loss study was performed using A549 and A549/DDP cells as an in-vitro model to investigate the effect of GAS5 on autophagy and cisplatin sensitivity. NSCLC tissues had a substantially lower expression of GAS5 than adjacent normal tissues. The NSCLC tissues from patients with progressive disease (PD) had even lower GAS5 expression. GAS5 knockdown increased DDP IC50 of A549 cells, while GAS5 overexpression decreased DDP IC50 of A549/DDP cells. A549/DDP cells had significantly higher basal autophagy than A549 cells. GAS5 knockdown resulted in decreased autophagy in A549 cells, while GAS5 overexpression led to increased autophagy in A549/DDP cells. Treatment with 3-MA, an autophagy inhibitor, significantly decreased DDP IC50 and promoted DDP-induced cell apoptosis in A549 cells. In addition, 3-MA also partly reversed the effect of GAS5 knockdown. In A549/DDP cells, GAS5 showed the similar effect as 3-MA in reducing DPP IC50 and promoting DDP-induced apoptosis and also presented synergic effect with 3-MA. GAS5 downregulation is associated with cisplatin resistance in NSCLC. GAS5 can inhibit autophagy and therefore enhance cisplatin sensitivity in NSCLC cells.

  11. Dendritic cells and immuno-modulation in autoimmune arthritis

    NARCIS (Netherlands)

    Spiering, R.|info:eu-repo/dai/nl/313939020

    2013-01-01

    The immune system consists of a broad array of immune cells to protect the body against invasive pathogenic microorganisms. Immune responses should however, be tightly controlled to ensure tolerance to the body’s own cells and proteins in order to limit damage to the host own cells and tissue.

  12. Using Mouse Mammary Tumor Cells to Teach Core Biology Concepts: A Simple Lab Module.

    Science.gov (United States)

    McIlrath, Victoria; Trye, Alice; Aguanno, Ann

    2015-06-18

    Undergraduate biology students are required to learn, understand and apply a variety of cellular and molecular biology concepts and techniques in preparation for biomedical, graduate and professional programs or careers in science. To address this, a simple laboratory module was devised to teach the concepts of cell division, cellular communication and cancer through the application of animal cell culture techniques. Here the mouse mammary tumor (MMT) cell line is used to model for breast cancer. Students learn to grow and characterize these animal cells in culture and test the effects of traditional and non-traditional chemotherapy agents on cell proliferation. Specifically, students determine the optimal cell concentration for plating and growing cells, learn how to prepare and dilute drug solutions, identify the best dosage and treatment time course of the antiproliferative agents, and ascertain the rate of cell death in response to various treatments. The module employs both a standard cell counting technique using a hemocytometer and a novel cell counting method using microscopy software. The experimental procedure lends to open-ended inquiry as students can modify critical steps of the protocol, including testing homeopathic agents and over-the-counter drugs. In short, this lab module requires students to use the scientific process to apply their knowledge of the cell cycle, cellular signaling pathways, cancer and modes of treatment, all while developing an array of laboratory skills including cell culture and analysis of experimental data not routinely taught in the undergraduate classroom.

  13. Probiotic Lactobacilli Modulate Staphylococcus aureus-Induced Activation of Conventional and Unconventional T cells and NK cells

    Directory of Open Access Journals (Sweden)

    Maria A Johansson

    2016-07-01

    Full Text Available Lactobacilli are probiotic commensal bacteria and potent modulators of immunity. When present in the gut or supplemented as probiotics, they beneficially modulate ex vivo immune responsiveness. Further, factors derived from several lactobacilli strains act immune regulato-ry in vitro. In contrast, Staphylococcus aureus (S. aureus is known to induce excessive T cell activation. In this study we aimed to investigate S. aureus-induced activation of human muco-sal associated invariant T cells (MAIT cells, γδ T cells, NK cells, as well as of conventional CD4+ and CD8+ T cells in vitro. Further, we investigated if lactobacilli-derived factors could modulate their activation.PBMC were cultured with S. aureus 161:2 cell free supernatant (CFS, staphylococcal en-terotoxin A or CD3/CD28-beads alone or in combination with Lactobacillus rhamnosus (L. rhamnosus GG-CFS or Lactobacillus reuteri (L. reuteri DSM 17938-CFS, and activation of T and NK cells was evaluated. S. aureus-CFS induced IFN-γ and CD107a expression as well as proliferation. Co-stimulation with lactobacilli-CFS dampened lymphocyte activation in all cell types analysed. Pre-incubation with lactobacilli-CFS was enough to reduce subsequent activation and the ab-sence of APC or APC-derived IL-10 did not prevent lactobacilli-mediated dampening. Final-ly, lactate selectively dampened activation of unconventional T cells and NK cells. In summary, we show that molecules present in the lactobacilli-CFS are able to directly dampen in vitro activation of conventional and unconventional T cells and of NK cells. This study provides novel insights on the immune modulatory nature of probiotic lactobacilli and suggests a role for lactobacilli in modulation of induced T and NK cell activation.

  14. Modulating Leukemia-Initiating Cell Quiescence to Improve Leukemia Treatment

    Science.gov (United States)

    2015-09-01

    T- cells and in innate immunity (Lacorazza et al., 2002). It controls the proliferation and homing of CD8+ T- cells via the Kruppel-like factors...Lin2Sca12IL7R2Kit1FccRII/ IIIhighCD34high), megakaryocyte-erythroid progenitor cell (MEP) (Lin2Sca12IL7R2Kit1FccRII/IIIlowCD34low), and common lymphoid ...to this model, the first wave gives rise exclusively to innate immune B cells in early embryonic life and may be derived from progenitor cells

  15. Lactobacilli Modulate Natural Killer Cell Responses In Vitro

    DEFF Research Database (Denmark)

    Fink, Lisbeth Nielsen; Christensen, Hanne Risager; Frøkiær, Hanne

    of certain lactic acid bacteria has been shown to increase in vivo NK cytotoxicity. Here, we investigated how human gut flora-derived lactobacilli affect NK cells in vitro, by measuring proliferation and IFN-gamma production of human NK cells upon bacterial stimulation. CD3-CD56+ NK cells were isolated from...... monocytes present, probably because cytokines, secreted by monocytes having engulfed bacteria, stimulated the NK cells. In contrast, a Lactobacillus paracasei strain caused the NK cells to proliferate only in the presence of monocytes. These results demonstrate that various strains of lactobacilli have...

  16. Gut microbiota modulate T cell trafficking into human colorectal cancer.

    Science.gov (United States)

    Cremonesi, Eleonora; Governa, Valeria; Garzon, Jesus Francisco Glaus; Mele, Valentina; Amicarella, Francesca; Muraro, Manuele Giuseppe; Trella, Emanuele; Galati-Fournier, Virginie; Oertli, Daniel; Däster, Silvio Raffael; Droeser, Raoul A; Weixler, Benjamin; Bolli, Martin; Rosso, Raffaele; Nitsche, Ulrich; Khanna, Nina; Egli, Adrian; Keck, Simone; Slotta-Huspenina, Julia; Terracciano, Luigi M; Zajac, Paul; Spagnoli, Giulio Cesare; Eppenberger-Castori, Serenella; Janssen, Klaus-Peter; Borsig, Lubor; Iezzi, Giandomenica

    2018-02-06

    Tumour-infiltrating lymphocytes (TILs) favour survival in human colorectal cancer (CRC). Chemotactic factors underlying their recruitment remain undefined. We investigated chemokines attracting T cells into human CRCs, their cellular sources and microenvironmental triggers. Expression of genes encoding immune cell markers, chemokines and bacterial 16S ribosomal RNA (16SrRNA) was assessed by quantitative reverse transcription-PCR in fresh CRC samples and corresponding tumour-free tissues. Chemokine receptor expression on TILs was evaluated by flow cytometry on cell suspensions from digested tissues. Chemokine production by CRC cells was evaluated in vitro and in vivo, on generation of intraperitoneal or intracecal tumour xenografts in immune-deficient mice. T cell trafficking was assessed on adoptive transfer of human TILs into tumour-bearing mice. Gut flora composition was analysed by 16SrRNA sequencing. CRC infiltration by distinct T cell subsets was associated with defined chemokine gene signatures, including CCL5, CXCL9 and CXCL10 for cytotoxic T lymphocytes and T-helper (Th)1 cells; CCL17, CCL22 and CXCL12 for Th1 and regulatory T cells; CXCL13 for follicular Th cells; and CCL20 and CCL17 for interleukin (IL)-17-producing Th cells. These chemokines were expressed by tumour cells on exposure to gut bacteria in vitro and in vivo. Their expression was significantly higher in intracecal than in intraperitoneal xenografts and was dramatically reduced by antibiotic treatment of tumour-bearing mice. In clinical samples, abundance of defined bacteria correlated with high chemokine expression, enhanced T cell infiltration and improved survival. Gut microbiota stimulate chemokine production by CRC cells, thus favouring recruitment of beneficial T cells into tumour tissues. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  17. Electric response of an electrolytic cell to a periodic excitation in the dc limit

    International Nuclear Information System (INIS)

    Alexe-Ionescu, A.L.; Barbero, G.; Duarte, A.R.; Saracco, G.

    2014-01-01

    We evaluate the electrical impedance of an electrolytic cell submitted to a low frequency external voltage. We show that in the limit where the circular frequency of the applied voltage, ω, is small with respect to Debye relaxation circular frequency, ω D , the response of the cell can be evaluated by means of a perturbational calculation, where the expansion parameter is x=ω/ω D . Simple expressions for the reactance and resistance in the dc limit of the electrolytic cell are obtained in the case where the electrodes are blocking and the diffusion coefficients of the negative and positive ions are equal. The case where the diffusion coefficients are different is also considered. In this framework, our analysis indicates that in the considered frequency range the effective diffusion coefficient coincides with the ambipolar diffusion coefficient. A possible extension of our approach to the case where the electrodes are not blocking is discussed too.

  18. Single cell amperometry reveals curcuminoids modulate the release of neurotransmitters during exocytosis from PC12 cells

    Science.gov (United States)

    Li, Xianchan; Mohammadi, Amir Saeid; Ewing, Andrew G.

    2016-01-01

    We used single cell amperometry to examine whether curcumin and bisdemethoxycurcumin (BDMC), substances that are suggested to affect learning and memory, can modulate monoamine release from PC12 cells. Our results indicate both curcumin and BDMC need long-term treatment (72 h in this study) to influence exocytosis effectively. By analyzing the parameters calculated from single exocytosis events, it can be concluded that curcumin and BDMC affect exocytosis through different mechanisms. Curcumin accelerates the event dynamics with no significant change of the monoamine amount released from single exocytotic events, whereas BDMC attenuates the amount from single exocytotic event with no significant change of the event dynamics. This comparison of the effect of curcumin and BDMC on exocytosis at the single cell level brings insight into their different mechanisms, which might lead to different biological actions. The effect of curcumin and BDMC on the opening and closing of the exocytotic fusion pore were also investigated. These results might be helpful for understanding the improvement of learning and memory and the anti-depression properties of curcuminoids. PMID:28579928

  19. Modulating the stem cell niche for tissue regeneration

    Science.gov (United States)

    Lane, Steven W; Williams, David A; Watt, Fiona M

    2015-01-01

    The field of regenerative medicine holds considerable promise for treating diseases that are currently intractable. Although many researchers are adopting the strategy of cell transplantation for tissue repair, an alternative approach to therapy is to manipulate the stem cell microenvironment, or niche, to facilitate repair by endogenous stem cells. The niche is highly dynamic, with multiple opportunities for intervention. These include administration of small molecules, biologics or biomaterials that target specific aspects of the niche, such as cell-cell and cell–extracellular matrix interactions, to stimulate expansion or differentiation of stem cells, or to cause reversion of differentiated cells to stem cells. Nevertheless, there are several challenges in targeting the niche therapeutically, not least that of achieving specificity of delivery and responses. We envisage that successful treatments in regenerative medicine will involve different combinations of factors to target stem cells and niche cells, applied at different times to effect recovery according to the dynamics of stem cell–niche interactions. PMID:25093887

  20. Exciter switch

    Science.gov (United States)

    Mcpeak, W. L.

    1975-01-01

    A new exciter switch assembly has been installed at the three DSN 64-m deep space stations. This assembly provides for switching Block III and Block IV exciters to either the high-power or 20-kW transmitters in either dual-carrier or single-carrier mode. In the dual-carrier mode, it provides for balancing the two drive signals from a single control panel located in the transmitter local control and remote control consoles. In addition to the improved switching capabilities, extensive monitoring of both the exciter switch assembly and Transmitter Subsystem is provided by the exciter switch monitor and display assemblies.

  1. Targeting CB2-GPR55 Receptor Heteromers Modulates Cancer Cell Signaling*

    Science.gov (United States)

    Moreno, Estefanía; Andradas, Clara; Medrano, Mireia; Caffarel, María M.; Pérez-Gómez, Eduardo; Blasco-Benito, Sandra; Gómez-Cañas, María; Pazos, M. Ruth; Irving, Andrew J.; Lluís, Carme; Canela, Enric I.; Fernández-Ruiz, Javier; Guzmán, Manuel; McCormick, Peter J.; Sánchez, Cristina

    2014-01-01

    The G protein-coupled receptors CB2 (CB2R) and GPR55 are overexpressed in cancer cells and human tumors. Because a modulation of GPR55 activity by cannabinoids has been suggested, we analyzed whether this receptor participates in cannabinoid effects on cancer cells. Here we show that CB2R and GPR55 form heteromers in cancer cells, that these structures possess unique signaling properties, and that modulation of these heteromers can modify the antitumoral activity of cannabinoids in vivo. These findings unveil the existence of previously unknown signaling platforms that help explain the complex behavior of cannabinoids and may constitute new targets for therapeutic intervention in oncology. PMID:24942731

  2. Fluorescence excitation-emission matrix (EEM) spectroscopy for rapid identification and quality evaluation of cell culture media components.

    Science.gov (United States)

    Li, Boyan; Ryan, Paul W; Shanahan, Michael; Leister, Kirk J; Ryder, Alan G

    2011-11-01

    The application of fluorescence excitation-emission matrix (EEM) spectroscopy to the quantitative analysis of complex, aqueous solutions of cell culture media components was investigated. These components, yeastolate, phytone, recombinant human insulin, eRDF basal medium, and four different chemically defined (CD) media, are used for the formulation of basal and feed media employed in the production of recombinant proteins using a Chinese Hamster Ovary (CHO) cell based process. The comprehensive analysis (either identification or quality assessment) of these materials using chromatographic methods is time consuming and expensive and is not suitable for high-throughput quality control. The use of EEM in conjunction with multiway chemometric methods provided a rapid, nondestructive analytical method suitable for the screening of large numbers of samples. Here we used multiway robust principal component analysis (MROBPCA) in conjunction with n-way partial least squares discriminant analysis (NPLS-DA) to develop a robust routine for both the identification and quality evaluation of these important cell culture materials. These methods are applicable to a wide range of complex mixtures because they do not rely on any predetermined compositional or property information, thus making them potentially very useful for sample handling, tracking, and quality assessment in biopharmaceutical industries.

  3. High Excitation Transfer Efficiency from Energy Relay Dyes in Dye-Sensitized Solar Cells

    KAUST Repository

    Hardin, Brian E.; Yum, Jun-Ho; Hoke, Eric T.; Jun, Young Chul; Péchy, Peter; Torres, Tomás; Brongersma, Mark L.; Nazeeruddin, Md. Khaja; Grätzel, Michael; McGehee, Michael D.

    2010-01-01

    The energy relay dye, 4-(Dicyanomethylene)-2-methyl-6-(4- dimethylaminostyryl)-4H-pyran (DCM), was used with a near-infrared sensitizing dye, TT1, to increase the overall power conversion efficiency of a dye-sensitized solar cell (DSC) from 3

  4. HDAC 1 and 6 modulate cell invasion and migration in clear cell renal cell carcinoma

    International Nuclear Information System (INIS)

    Ramakrishnan, Swathi; Ku, ShengYu; Ciamporcero, Eric; Miles, Kiersten Marie; Attwood, Kris; Chintala, Sreenivasulu; Shen, Li; Ellis, Leigh; Sotomayor, Paula; Swetzig, Wendy; Huang, Ray; Conroy, Dylan; Orillion, Ashley; Das, Gokul; Pili, Roberto

    2016-01-01

    Class I histone deacetylases (HDACs) have been reported to be overexpressed in clear cell renal cell carcinoma (ccRCC), whereas the expression of class II HDACs is unknown. Four isogenic cell lines C2/C2VHL and 786-O/786-OVHL with differential VHL expression are used in our studies. Cobalt chloride is used to mimic hypoxia in vitro. HIF-2α knockdowns in C2 and 786-O cells is used to evaluate the effect on HDAC 1 expression and activity. Invasion and migration assays are used to investigate the role of HDAC 1 and HDAC 6 expression in ccRCC cells. Comparisons are made between experimental groups using the paired T-test, the two-sample Student’s T-test or one-way ANOVA, as appropriate. ccRCC and the TCGA dataset are used to observe the clinical correlation between HDAC 1 and HDAC 6 overexpression and overall and progression free survival. Our analysis of tumor and matched non-tumor tissues from radical nephrectomies showed overexpression of class I and II HDACs (HDAC6 only in a subset of patients). In vitro, both HDAC1 and HDAC6 over-expression increased cell invasion and motility, respectively, in ccRCC cells. HDAC1 regulated invasiveness by increasing matrix metalloproteinase (MMP) expression. Furthermore, hypoxia stimulation in VHL-reconstituted cell lines increased HIF isoforms and HDAC1 expression. Presence of hypoxia response elements in the HDAC1 promoter along with chromatin immunoprecipitation data suggests that HIF-2α is a transcriptional regulator of HDAC1 gene. Conversely, HDAC6 and estrogen receptor alpha (ERα) were co-localized in cytoplasm of ccRCC cells and HDAC6 enhanced cell motility by decreasing acetylated α-tubulin expression, and this biological effect was attenuated by either biochemical or pharmacological inhibition. Finally, analysis of human ccRCC specimens revealed positive correlation between HIF isoforms and HDAC. HDAC1 mRNA upregulation was associated with worse overall survival in the TCGA dataset. Taking together, these results

  5. Transient response of a polymer electrolyte membrane fuel cell subjected to time-varying modulating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Noorani, S.; Shamim, T. [Michigan-Dearborn Univ., Dearborn, MI (United States). Dept. of Mechanical Engineering

    2009-07-01

    In order for fuel cells to compete with internal combustion engines, they must have significant advantages in terms of overall efficiency, weight, packaging, safety and cost. A key requirement is its ability to operate under highly transient conditions during start-up, acceleration, and deceleration with stable performance. Therefore, a better understanding of fuel cell dynamic behaviour is needed along with better water management and distributions inside the cell. Therefore, this study investigated the effect of transient conditions on water distribution inside a polymer electrolyte membrane (PEM) cell. A macroscopic single-fuel cell based, one-dimensional, isothermal mathematical model was used to study the effect of modulating cell voltage on the water distribution of anode, cathode, catalyst layers, and membrane. Compared to other existing models, this model did not rely on the non-physical assumption of the uptake curve equilibrium between the pore vapour and ionomer water in the catalyst layers. Instead, the transition between the two phases was modeled as a finite-rate equilibration process. The modulating conditions were simulated by forcing the temporal variations in fuel cell voltage. The results revealed that cell voltage modulations cause a departure in the cell behaviour from its steady behaviour, and the finite-rate equilibration between the catalyst vapour and liquid water can be a factor in determining the cell response. The cell response is also affected by the modulating frequency and amplitude. The peak cell response was observed at low frequencies. Keywords: fuel cell, water transport, dynamic behaviour, numerical simulations. 9 refs., 1 tab., 5 figs.

  6. Modulation of hepatocarcinoma cell morphology and activity by parylene-C coating on PDMS.

    Directory of Open Access Journals (Sweden)

    Nazaré Pereira-Rodrigues

    Full Text Available BACKGROUND: The ability to understand and locally control the morphogenesis of mammalian cells is a fundamental objective of cell and developmental biology as well as tissue engineering research. We present parylene-C (ParC deposited on polydimethylsiloxane (PDMS as a new substratum for in vitro advanced cell culture in the case of Human Hepatocarcinoma (HepG2 cells. PRINCIPAL FINDINGS: Our findings establish that the intrinsic properties of ParC-coated PDMS (ParC/PDMS influence and modulate initial extracellular matrix (ECM; here, type-I collagen surface architecture, as compared to non-coated PDMS substratum. Morphological changes induced by the presence of ParC on PDMS were shown to directly affect liver cell metabolic activity and the expression of transmembrane receptors implicated in cell adhesion and cell-cell interaction. These changes were characterized by atomic force microscopy (AFM, which elucidated differences in HepG2 cell adhesion, spreading, and reorganization into two- or three-dimensional structures by neosynthesis of ECM components. Local modulation of cell aggregation was successfully performed using ParC/PDMS micropatterns constructed by simple microfabrication. CONCLUSION/SIGNIFICANCE: We demonstrated for the first time the modulation of HepG2 cells' behavior in relation to the intrinsic physical properties of PDMS and ParC, enabling the local modulation of cell spreading in a 2D or 3D manner by simple microfabrication techniques. This work will provide promising insights into the development of cell-based platforms that have many applications in the field of in vitro liver tissue engineering, pharmacology and therapeutics.

  7. Development and testing of shingle-type solar cell modules. Quarterly report No. 2

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, N.F.

    1978-01-05

    The details of a shingle module design which produces in excess of 97 watts/m/sup 2/ of module area at 1 kW/m/sup 2/ insolation and at 60/sup 0/C are reported. This selected design employs a tempered glass coverplate to provide the primary solar cell structural support. The use of the B.F. Goodrich FLEXSEAL roofing system as the outer skin of the shingle substrate provides a high confidence of achieving the 15 year service life goal. The fabrication and testing of a preproduction module of this design has demonstrated that this selected approach will meet the environmental testing requirements imposed by the contract. Attempts to fabricate a preproduction module of an alternative design, which embeds the solar cell assembly within a methyl methacrylate casting, proved unsuccessful.

  8. Convective cell excitation by inertial Alfven waves in a low density plasma

    International Nuclear Information System (INIS)

    Pokhotelov, O.A.; Onishchenko, O.G.; Sagdeev, R.Z.; Srenflo, L.; Balikhin, M.A.

    2005-01-01

    The parametric interaction of inertial Alfven waves with large-scale convective cells in a low-density plasma is investigated. It is shown that, in plasmas where the Alfven velocity is comparable to or exceeds the speed of light, the parametric interaction is substantially suppressed. A compact expression for the optimal scale and instability growth rate of the fastest growing mode is obtained [ru

  9. Modulation of vesicular catecholamine release from rat PC12 cells

    NARCIS (Netherlands)

    Westerink, R.H.S.

    2002-01-01

    Intercellular communication is of vital importance for the nervous system, since the nervous system is the main coordinating system in animals. Nerve cell communication is initiated by the release of chemical messengers, neurotransmitters, from the presynaptic nerve cell. The neurotransmitters, such

  10. Evidence That Androgens Modulate Human Thymic T Cell Output

    Science.gov (United States)

    Olsen, Nancy J.; Kovacs, William J.

    2010-01-01

    Background The thymus has long been recognized as a target for the actions of androgenic hormones, but it has only been recently recognized that alterations in circulating levels of gonadal steroids might affect thymic output of T cells. We had the opportunity to examine parameters of thymic cellular output in several hypogonadal men undergoing androgen replacement therapy. Methods Circulating naive (CD4+CD45RA+) T cells were quantitated by flow cytometric analysis of peripheral blood mononuclear cells (PBMCs). Cells bearing T cell receptor excision circles (TRECs) were quantitated using real-time PCR amplification of DNA isolated from PBMCs from normal men and from hypogonadal men before and after testosterone replacement therapy. Results CD4+CD45+ (“naïve”) T cells comprised 10.5% of lymphocytes in normal males; this proportion was greatly increased in two hypogonadal men (35.5% and 44.4%). One man was studied sequentially during treatment with physiologic doses of testosterone. CD4+CD45RA+ cells fell from 37.36% to 20.05% after one month and to 12.51% after 7 months of normalized androgen levels. In two hypogonadal patients TREC levels fell by 83% and 78% after androgen replacement therapy. Conclusions Our observations indicate that the hypogonadal state is associated with increased thymic output of T cells and that this increase in recent thymic emigrants in peripheral blood is reversed by androgen replacement. PMID:21218609

  11. Immune modulation by dendritic-cell-based cancer vaccines

    Indian Academy of Sciences (India)

    The interplay between host immunity and tumour cells has opened the possibility of targeting tumour cells bymodulation of the human immune system. Cancer immunotherapy involves the treatment of a tumour by utilizing therecombinant human immune system components to target the pro-tumour microenvironment or by ...

  12. Hybrid cellular automaton modeling of nutrient modulated cell growth in tissue engineering constructs.

    Science.gov (United States)

    Chung, C A; Lin, Tze-Hung; Chen, Shih-Di; Huang, Hsing-I

    2010-01-21

    Mathematic models help interpret experimental results and accelerate tissue engineering developments. We develop in this paper a hybrid cellular automata model that combines the differential nutrient transport equation to investigate the nutrient limited cell construct development for cartilage tissue engineering. Individual cell behaviors of migration, contact inhibition and cell collision, coupled with the cell proliferation regulated by oxygen concentration were carefully studied. Simplified two-dimensional simulations were performed. Using this model, we investigated the influence of cell migration speed on the overall cell growth within in vitro cell scaffolds. It was found that intense cell motility can enhance initial cell growth rates. However, since cell growth is also significantly modulated by the nutrient contents, intense cell motility with conventional uniform cell seeding method may lead to declined cell growth in the final time because concentrated cell population has been growing around the scaffold periphery to block the nutrient transport from outside culture media. Therefore, homogeneous cell seeding may not be a good way of gaining large and uniform cell densities for the final results. We then compared cell growth in scaffolds with various seeding modes, and proposed a seeding mode with cells initially residing in the middle area of the scaffold that may efficiently reduce the nutrient blockage and result in a better cell amount and uniform cell distribution for tissue engineering construct developments.

  13. Aortic calcified particles modulate valvular endothelial and interstitial cells.

    Science.gov (United States)

    van Engeland, Nicole C A; Bertazzo, Sergio; Sarathchandra, Padmini; McCormack, Ann; Bouten, Carlijn V C; Yacoub, Magdi H; Chester, Adrian H; Latif, Najma

    Normal and calcified human valve cusps, coronary arteries, and aortae harbor spherical calcium phosphate microparticles of identical composition and crystallinity, and their role remains unknown. The objective was to examine the direct effects of isolated calcified particles on human valvular cells. Calcified particles were isolated from healthy and diseased aortae, characterized, quantitated, and applied to valvular endothelial cells (VECs) and interstitial cells (VICs). Cell differentiation, viability, and proliferation were analyzed. Particles were heterogeneous, differing in size and shape, and were crystallized as calcium phosphate. Diseased donors had significantly more calcified particles compared to healthy donors (Pinnocent bystanders but induce a phenotypical and pathological change of VECs and VICs characteristic of activated and pathological cells. Therapy tailored to reduce these calcified particles should be investigated. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Mast cell function modulating IgE-mediated allergy

    Directory of Open Access Journals (Sweden)

    Ruby Pawankar

    1999-01-01

    Full Text Available Allergic diseases, such as atopic rhinitis, bronchial asthma and urticaria, are prevalent and increasing in frequency. Mast cells are known to play a central role in the immediate phase reaction of allergic diseases through the IgE-mediated release of a variety of chemical mediators, such as histamine, leukotrienes and prostaglandins. In contrast, T lymphocytes, basophils and eosinophils are thought to be responsible for inducing the late phase response. However, whether the mast cell can be simplistically assigned a role in the immediate phase allergic response and whether mast cells are necessary for the ongoing allergic response, including the development of hyperresponsiveness, remains to be completely studied. In the present article, the author will discuss the integrated roles of mast cells in IgE-mediated allergic inflammation, with specific emphasis on the roles of mast cell-derived cytokines in the late phase allergic response and chronic allergic inflammation.

  15. Oct4 targets regulatory nodes to modulate stem cell function.

    Directory of Open Access Journals (Sweden)

    Pearl A Campbell

    2007-06-01

    Full Text Available Stem cells are characterized by two defining features, the ability to self-renew and to differentiate into highly specialized cell types. The POU homeodomain transcription factor Oct4 (Pou5f1 is an essential mediator of the embryonic stem cell state and has been implicated in lineage specific differentiation, adult stem cell identity, and cancer. Recent description of the regulatory networks which maintain 'ES' have highlighted a dual role for Oct4 in the transcriptional activation of genes required to maintain self-renewal and pluripotency while concomitantly repressing genes which facilitate lineage specific differentiation. However, the molecular mechanism by which Oct4 mediates differential activation or repression at these loci to either maintain stem cell identity or facilitate the emergence of alternate transcriptional programs required for the realization of lineage remains to be elucidated. To further investigate Oct4 function, we employed gene expression profiling together with a robust statistical analysis to identify genes highly correlated to Oct4. Gene Ontology analysis to categorize overrepresented genes has led to the identification of themes which may prove essential to stem cell identity, including chromatin structure, nuclear architecture, cell cycle control, DNA repair, and apoptosis. Our experiments have identified previously unappreciated roles for Oct4 for firstly, regulating chromatin structure in a state consistent with self-renewal and pluripotency, and secondly, facilitating the expression of genes that keeps the cell poised to respond to cues that lead to differentiation. Together, these data define the mechanism by which Oct4 orchestrates cellular regulatory pathways to enforce the stem cell state and provides important insight into stem cell function and cancer.

  16. Ethanol modulation of mammalian BK channels in excitable tissues: molecular targets and their possible contribution to alcohol-induced altered behavior

    Directory of Open Access Journals (Sweden)

    Alex M. Dopico

    2014-12-01

    Full Text Available In most tissues, the function of calcium- and voltage-gated potassium (BK channels is modified in response to ethanol concentrations reached in human blood during alcohol intoxication. In general, modification of BK current from ethanol-naïve preparations in response to brief ethanol exposure results from changes in channel open probability without modification of unitary conductance or change in BK protein levels in the membrane. Protracted and/or repeated ethanol exposure, however, may evoke changes in BK expression. The final ethanol effect on BK open probability leading to either BK current potentiation or BK current reduction is determined by an orchestration of molecular factors, including levels of activating ligand (cytosolic calcium, BK subunit composition and posttranslational modifications, and the channel’s lipid microenvironment. These factors seem to allosterically regulate a direct interaction between ethanol and a recognition pocket of discrete dimensions recently mapped to the channel-forming (slo1 subunit. Type of ethanol exposure also plays a role in the final BK response to the drug: in several central nervous system regions (e.g., striatum, primary sensory neurons, and supraoptic nucleus, acute exposure to ethanol reduces neuronal excitability by enhancing BK activity. In contrast, protracted or repetitive ethanol administration may alter BK subunit composition and membrane expression, rendering the BK complex insensitive to further ethanol exposure. In neurohypophysial axon terminals, ethanol potentiation of BK channel activity leads to a reduction in neuropeptide release. In vascular smooth muscle, however, ethanol inhibition of BK current leads to cell contraction and vascular constriction.

  17. Modulating Estrogen Receptor-related Receptor-α Activity Inhibits Cell Proliferation*

    OpenAIRE

    Bianco, Stéphanie; Lanvin, Olivia; Tribollet, Violaine; Macari, Claire; North, Sophie; Vanacker, Jean-Marc

    2009-01-01

    High expression of the estrogen receptor-related receptor (ERR)-α in human tumors is correlated to a poor prognosis, suggesting an involvement of the receptor in cell proliferation. In this study, we show that a synthetic compound (XCT790) that modulates the activity of ERRα reduces the proliferation of various cell lines and blocks the G1/S transition of the cell cycle in an ERR...

  18. Five-cell superconducting RF module with a PBG coupler cell: design and cold testing of the copper prototype

    Energy Technology Data Exchange (ETDEWEB)

    Arsenyev, Sergey Andreyevich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Simakov, Evgenya Ivanovna [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Shchegolkov, Dmitry [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Boulware, Chase [Niowave, Lansing, MI (United States); Grimm, Terry [Niowave, Lansing, MI (United States); Rogacki, Adam [Niowave, Lansing, MI (United States)

    2015-04-29

    We report the design and experimental data for a copper prototype of a superconducting radio-frequency (SRF) accelerator module. The five-cell module has an incorporated photonic band gap (PBG) cell with couplers. The purpose of the PBG cell is to achieve better higher order mode (HOM) damping, which is vital for preserving the quality of high-current electron beams. Better HOM damping raises the current threshold for beam instabilities in novel SRF accelerators. The PBG design also increases the real-estate gradient of the linac because both HOM damping and the fundamental power coupling can be done through the PBG cell instead of on the beam pipe via complicated end assemblies. First, we will discuss the design and accelerating properties of the structure. The five-cell module was optimized to provide good HOM damping while maintaining the same accelerating properties as conventional elliptical-cell modules. We will then discuss the process of tuning the structure to obtain the desired accelerating gradient profile. Finally, we will list measured quality factors for the accelerating mode and the most dangerous HOMs.

  19. Modulation of immune response by alloactivated suppressor T cells

    International Nuclear Information System (INIS)

    Bernstein, A.; Sopori, M.L.; Gose, J.E.; Sondel, P.M.

    1979-01-01

    These studies show that there may be several different kinds of suppressor cells, each activated by different pathways and able to suppress different parts of the immune response either specifically or nonspecifically. As such, the physiology of one type of suppressor cell need not necessarily apply to that of another type of suppressor. Thus we emphasize the trap that the suppressor cell option provides: that is, virtually any previously inexplicable in vitro and in vivo immune phenomenon can always be adequately accounted for by evoking a suppressor mechanism, either by suppressing the response or suppressing the suppressor

  20. Standard Test Methods for Electrical Performance of Nonconcentrator Terrestrial Photovoltaic Modules and Arrays Using Reference Cells

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 These test methods cover the electrical performance of photovoltaic modules and arrays under natural or simulated sunlight using a calibrated reference cell. 1.1.1 These test methods allow a reference module to be used instead of a reference cell provided the reference module has been calibrated using these test methods against a calibrated reference cell. 1.2 Measurements under a variety of conditions are allowed; results are reported under a select set of reporting conditions (RC) to facilitate comparison of results. 1.3 These test methods apply only to nonconcentrator terrestrial modules and arrays. 1.4 The performance parameters determined by these test methods apply only at the time of the test, and imply no past or future performance level. 1.5 These test methods apply to photovoltaic modules and arrays that do not contain series-connected photovoltaic multijunction devices; such module and arrays should be tested according to Test Methods E 2236. 1.6 The values stated in SI units are to be re...

  1. Regulation of granule cell excitability by a low-threshold calcium spike in turtle olfactory bulb

    DEFF Research Database (Denmark)

    Pinato, Giulietta; Midtgaard, Jens

    2003-01-01

    of the cell usually increased their amplitude so that they more easily boosted Na spike initiation. The LTS persisted in the presence of TTX but was antagonized by blockers of T-type calcium channels. The voltage dependence, kinetics, and inactivation properties of the LTS were characteristic of a low......-threshold calcium spike. The threshold of the LTS was slightly above the resting potential but well below the Na spike threshold, and the LTS was often evoked in isolation in normal medium. Tetraethylammonium (TEA) and 4-aminopyridine (4-AP) had only minimal effects on the LTS but revealed the presence of a high...

  2. Scalability of multi-junction organic solar cells for large area organic solar modules

    Science.gov (United States)

    Xiao, Xin; Lee, Kyusang; Forrest, Stephen R.

    2015-05-01

    We investigate the scalability of multi-junction organic photovoltaic cells (OPV) with device areas ranging from 1 mm2 to 1 cm2, as well as 25 cm2 active area solar modules. We find that the series resistance losses in 1 cm2 vs. 1 mm2 OPV cell efficiencies are significantly higher in single junction cells than tandem, triple, and four junction cells due to the lower operating voltage and higher current of the former. Using sub-electrodes to reduce series resistance, the power conversion efficiency (PCE) of multi-junction cells is almost independent of area from 1 mm2 to 1 cm2. Twenty-five, 1 cm2 multi-junction cell arrays are integrated in a module and connected in a series-parallel circuit configuration. A yield of 100% with a deviation of PCE from cell to cell of <10% is achieved. The module generates an output power of 162 ± 9 mW under simulated AM1.5G illumination at one sun intensity, corresponding to PCE = 6.5 ± 0.1%, slightly lower than PCE of discrete cells ranging from 6.7% to 7.2%.

  3. Nonlinear spectral imaging of human normal skin, basal cell carcinoma and squamous cell carcinoma based on two-photon excited fluorescence and second-harmonic generation

    Science.gov (United States)

    Xiong, S. Y.; Yang, J. G.; Zhuang, J.

    2011-10-01

    In this work, we use nonlinear spectral imaging based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) for analyzing the morphology of collagen and elastin and their biochemical variations in basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and normal skin tissue. It was found in this work that there existed apparent differences among BCC, SCC and normal skin in terms of their thickness of the keratin and epithelial layers, their size of elastic fibers, as well as their distribution and spectral characteristics of collagen. These differences can potentially be used to distinguish BCC and SCC from normal skin, and to discriminate between BCC and SCC, as well as to evaluate treatment responses.

  4. Modulation of NF-KB in rescued irradiated cells

    International Nuclear Information System (INIS)

    Lam, R.K.K.; Fung, Y.K.; Han, W.; Li, L.; Chiu, S.K.; Cheng, S.H.; Yu, K.N.

    2015-01-01

    Studies by different groups on the rescue effect, where unirradiated bystander cells mitigated the damages in the irradiated cells, since its discovery by the authors' group in 2011 were first reviewed. The properties of the rescue effect were then examined using a novel experimental set-up to physically separate the rescue signals from the bystander signals. The authors' results showed that the rescue effect was mediated through activation of the nuclear factor-KB (NF-KB) response pathway in the irradiated cells, and that the NF-KB activation inhibitor BAy -1 1-7082 did not affect the activation of this response pathway in the irradiated cells induced by direct irradiation. (authors)

  5. High Efficiency, High Density Terrestrial Panel. [for solar cell modules

    Science.gov (United States)

    Wohlgemuth, J.; Wihl, M.; Rosenfield, T.

    1979-01-01

    Terrestrial panels were fabricated using rectangular cells. Packing densities in excess of 90% with panel conversion efficiencies greater than 13% were obtained. Higher density panels can be produced on a cost competitive basis with the standard salami panels.

  6. Cell state switching factors and dynamical patterning modules ...

    Indian Academy of Sciences (India)

    Prakash

    segmented, differentiated and additional complex structures, with minimal evolution ...... (b, c) Hematoxylin and Oil-red (lipid specific) staining of low density cell culture grown ..... description to elaborated structural and functional classification;.

  7. Cell proliferation in vitro modulates fibroblast collagenase activity

    International Nuclear Information System (INIS)

    Lindblad, W.J.; Flood, L.

    1986-01-01

    Collagenase enzyme activity is regulated by numerous control mechanisms which prevent excessive release and activation of this protease. A primary mechanism for regulating enzyme extracellular activity may be linked to cell division, therefore they have examined the release of collagenase by fibroblasts in vitro in response to cellular proliferation. Studies were performed using fibroblasts derived from adult rat dermis maintained in DMEM containing 10% newborn calf serum, 25 mM tricine buffer, and antibiotics. Cells between subculture 10 and 19 were used with enzyme activity determined with a 14 C-labelled soluble Type I collagen substrate with and without trypsin activation. Fibroblasts, trypsinized and plated at low density secreted 8.5 fold more enzyme than those cells at confluence (975 vs. 115 dpm/μg DNA). This diminution occurred gradually as the cells went from logrithmic growth towards confluence. Confluent fibroblast monolayers were scraped in a grid arrangement, stimulating the remaining cells to divide, without exposure to trypsin. Within 24-48 hr postscraping enzyme levels had increased 260-400%, accompanied by enhanced incorporation of 3 H-thymidine and 3 H-uridine into cell macromolecules. The burst of enzyme release began to subside 12 hr later. These results support a close relationship between fibroblast proliferation and collagenase secretion

  8. 5-Fluorouracil modulation of radiosensitivity in cultured human carcinoma cells

    International Nuclear Information System (INIS)

    Smalley, S.R.; Kimler, B.F.; Evans, R.G.

    1991-01-01

    We evaluated conventional pulse exposure versus continuous exposure models of 5-fluorouracil (5-FU) radiosensitization in HT-29 (human colon adenocarcinoma) and DU-145 (human prostate cancer adenocarcinoma) cell lines. Cell survival following treatment with drug and/or radiation was determined by colony formation assays. Radiation was delivered either by itself, approximately midway through a 1-hr exposure to 5-FU (10 micrograms/ml), or at various times following initiation of exposure to 5-FU (0.5 microgram/ml) present throughout the entire period of incubation. Drug concentrations were selected to approximate those achieved in vivo in humans. HT-29 cells showed a plating efficiency of 87% and similar cytotoxicity (survival reduced to 0.57-0.71) for all 5-FU conditions. The Do's of the radiation survival curves were not different for 1 hr of 5-FU exposure versus radiation alone. However, continuous exposure conditions demonstrated statistically significantly different Do's from radiation alone and pulse 5-FU exposure. DU-145 cells displayed a plating efficiency of 17% and cytotoxicities of 0.10-0.91 for the 5-FU conditions. DU-145 cells showed different radiation 5-FU interactions: 5-FU produced statistically significant changes in Do well as the differences between cell lines insofar as their radiosensitization by 5-FU underscore the caution required in extrapolating these radiobiologic models to the clinical setting

  9. Voltage equalization of an ultracapacitor module by cell grouping using number partitioning algorithm

    Science.gov (United States)

    Oyarbide, E.; Bernal, C.; Molina, P.; Jiménez, L. A.; Gálvez, R.; Martínez, A.

    2016-01-01

    Ultracapacitors are low voltage devices and therefore, for practical applications, they need to be used in modules of series-connected cells. Because of the inherent manufacturing tolerance of the capacitance parameter of each cell, and as the maximum voltage value cannot be exceeded, the module requires inter-cell voltage equalization. If the intended application suffers repeated fast charging/discharging cycles, active equalization circuits must be rated to full power, and thus the module becomes expensive. Previous work shows that a series connection of several sets of paralleled ultracapacitors minimizes the dispersion of equivalent capacitance values, and also the voltage differences between capacitors. Thus the overall life expectancy is improved. This paper proposes a method to distribute ultracapacitors with a number partitioning-based strategy to reduce the dispersion between equivalent submodule capacitances. Thereafter, the total amount of stored energy and/or the life expectancy of the device can be considerably improved.

  10. Enthesis fibrocartilage cells originate from a population of Hedgehog-responsive cells modulated by the loading environment.

    Science.gov (United States)

    Schwartz, Andrea G; Long, Fanxin; Thomopoulos, Stavros

    2015-01-01

    Tendon attaches to bone across a specialized tissue called the enthesis. This tissue modulates the transfer of muscle forces between two materials, i.e. tendon and bone, with vastly different mechanical properties. The enthesis for many tendons consists of a mineralized graded fibrocartilage that develops postnatally, concurrent with epiphyseal mineralization. Although it is well described that the mineralization and development of functional maturity requires muscle loading, the biological factors that modulate enthesis development are poorly understood. By genetically demarcating cells expressing Gli1 in response to Hedgehog (Hh) signaling, we discovered a unique population of Hh-responsive cells in the developing murine enthesis that were distinct from tendon fibroblasts and epiphyseal chondrocytes. Lineage-tracing experiments revealed that the Gli1 lineage cells that originate in utero eventually populate the entire mature enthesis. Muscle paralysis increased the number of Hh-responsive cells in the enthesis, demonstrating that responsiveness to Hh is modulated in part by muscle loading. Ablation of the Hh-responsive cells during the first week of postnatal development resulted in a loss of mineralized fibrocartilage, with very little tissue remodeling 5 weeks after cell ablation. Conditional deletion of smoothened, a molecule necessary for responsiveness to Ihh, from the developing tendon and enthesis altered the differentiation of enthesis progenitor cells, resulting in significantly reduced fibrocartilage mineralization and decreased biomechanical function. Taken together, these results demonstrate that Hh signaling within developing enthesis fibrocartilage cells is required for enthesis formation. © 2015. Published by The Company of Biologists Ltd.

  11. Multi-crystalline II-VI based multijunction solar cells and modules

    Science.gov (United States)

    Hardin, Brian E.; Connor, Stephen T.; Groves, James R.; Peters, Craig H.

    2015-06-30

    Multi-crystalline group II-VI solar cells and methods for fabrication of same are disclosed herein. A multi-crystalline group II-VI solar cell includes a first photovoltaic sub-cell comprising silicon, a tunnel junction, and a multi-crystalline second photovoltaic sub-cell. A plurality of the multi-crystalline group II-VI solar cells can be interconnected to form low cost, high throughput flat panel, low light concentration, and/or medium light concentration photovoltaic modules or devices.

  12. Efficiency improvements by Metal Wrap Through technology for n-type Si solar cells and modules

    Energy Technology Data Exchange (ETDEWEB)

    Wenchao, Zhao; Jianming, Wang; Yanlong, Shen; Ziqian, Wang; Yingle, Chen; Shuquan, Tian; Zhiliang, Wan; Bo, Yu; Gaofei, Li; Zhiyan, Hu; Jingfeng, Xiong [Yingli Green Energy Holding Co., Ltd, 3399 North Chaoyang Avenue, Baoding (China); Guillevin, N.; Heurtault, B.; Aken, B.B. van; Bennett, I.J.; Geerligs, L.J.; Weeber, A.W.; Bultman, J.H. [ECN Solar Energy, Petten (Netherlands)

    2012-09-15

    N-type Metal Wrap Through (n-MWT) is presented as an industrially promising back-contact technology to reach high performance of silicon solar cells and modules. It can combine benefits from both n-type base and MWT metallization. In this paper, the efficiency improvements of commercial industrial n-type bifacial Si solar cells (239 cm{sup 2}) and modules (60 cells) by the integration of the MWT technique are described. For the cell, after the optimization of integration, over 0.3% absolute efficiency gain was achieved over the similar non-MWT technology, and Voc gain and Isc gain up to 0.9% and 3.5%, respectively. These gains are mainly attributed to reduced shading loss and surface recombination. Besides the front pattern optimization, a 0.1m{Omega} reduction of Rs in via part will induce further 0.06% absolute efficiency improvement. For the module part, a power output of n-MWT module up to 279W was achieved, corresponding to a module efficiency of about 17.7%.

  13. Solar concentrator modules with silicone-on-glass Fresnel lens panels and multijunction cells.

    Science.gov (United States)

    Rumyantsev, Valery D

    2010-04-26

    High-efficiency multijunction (MJ) solar cells, being very expensive to manufacture, should only be used in combination with solar concentrators in terrestrial applications. An essential cost reduction of electric power produced by photovoltaic (PV) installations with MJ cells, may be expected by the creation of highly-effective, but inexpensive, elements for optical concentration and sun tracking. This article is an overview of the corresponding approach under development at the Ioffe Physical Technical Institute. The approach to R&D of the solar PV modules is based on the concepts of sunlight concentration by small-aperture area Fresnel lenses and "all-glass" module design. The small-aperture area lenses are arranged as a panel with silicone-on-glass structure where the glass plate serves as the front surface of a module. In turn, high-efficiency InGaP/(In)GaAs/Ge cells are arranged on a rear module panel mounted on a glass plate which functions as a heat sink and integrated protective cover for the cells. The developed PV modules and sun trackers are characterized by simple design, and are regarded as the prototypes for further commercialization.

  14. Solar concentrator modules with silicone-onglass Fresnel lens panels and multijunction cells.

    Science.gov (United States)

    Rumyantsev, Valery D

    2010-04-26

    High-efficiency multijunction (MJ) solar cells, being very expensive to manufacture, should only be used in combination with solar concentrators in terrestrial applications. An essential cost reduction of electric power produced by photovoltaic (PV) installations with MJ cells, may be expected by the creation of highly-effective, but inexpensive, elements for optical concentration and sun tracking. This article is an overview of the corresponding approach under development at the Ioffe Physical Technical Institute. The approach to R&D of the solar PV modules is based on the concepts of sunlight concentration by small-aperture area Fresnel lenses and "all-glass" module design. The small-aperture area lenses are arranged as a panel with silicone-on-glass structure where the glass plate serves as the front surface of a module. In turn, high-efficiency InGaP/(In)GaAs/Ge cells are arranged on a rear module panel mounted on a glass plate which functions as a heat sink and integrated protective cover for the cells. The developed PV modules and sun trackers are characterized by simple design, and are regarded as the prototypes for further commercialization.

  15. A Low-Energy-Gap Thienochrysenocarbazole Dye for Highly Efficient Mesoscopic Titania Solar Cells: Understanding the Excited State and Charge Carrier Dynamics.

    Science.gov (United States)

    Wang, Junting; Xie, Xinrui; Weng, Guorong; Yuan, Yi; Zhang, Jing; Wang, Peng

    2018-05-09

    Maintaining both a high external quantum efficiency and a large open-circuit photovoltage of dye-sensitized solar cells (DSSCs) is a crucial challenge in the process of developing narrow-energy-gap dyes for the capture of infrared solar photons. Herein, we report two donor-acceptor organic dyes, C294 and C295, with a polycyclic heteroaromatic unit, 6,11-dihydrothieno[3',2':8,9]chryseno[10,11,12,1-bcdefg]carbazole (TCC), as the central module of the electron donor, and ethylbenzothiadiazole-benzioc acid as the electron acceptor. The interfacial charge recombination was successfully mitigated by introducing an additional branched aliphatic chain in C295. Furthermore, the O⋅⋅⋅S nonbonding interaction between the oxygen atom of the alkoxy group and the sulfur atom of the thiophene in C295 controlled the conformation of C295, resulting in a narrow energy-gap. Time-resolved spectroscopic measurements on C294 and the model dye C272 indicated that the elevation of the HOMO energy level decreased the kinetics and yield of hole injection owing to a reduction in the driving force and that the shortened excited-state lifetime caused by the narrowing of the energy gap was unfavorable for electron injection. By fine tuning the composition of the electrolyte, C294 and C295 eventually achieved high power conversion efficiencies of 11.5 % and 12.4 %, respectively, under full sunlight of air mass 1.5 global conditions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. The duration of mitosis and daughter cell size are modulated by nutrients in budding yeast.

    Science.gov (United States)

    Leitao, Ricardo M; Kellogg, Douglas R

    2017-11-06

    The size of nearly all cells is modulated by nutrients. Thus, cells growing in poor nutrients can be nearly half the size of cells in rich nutrients. In budding yeast, cell size is thought to be controlled almost entirely by a mechanism that delays cell cycle entry until sufficient growth has occurred in G1 phase. Here, we show that most growth of a new daughter cell occurs in mitosis. When the rate of growth is slowed by poor nutrients, the duration of mitosis is increased, which suggests that cells compensate for slow growth in mitosis by increasing the duration of growth. The amount of growth required to complete mitosis is reduced in poor nutrients, leading to a large reduction in cell size. Together, these observations suggest that mechanisms that control the extent of growth in mitosis play a major role in cell size control in budding yeast. © 2017 Leitao and Kellogg.

  17. Implementation of a Service-learning Module in Medical Microbiology and Cell Biology Classes at an Undergraduate Liberal Arts University.

    Science.gov (United States)

    Larios-Sanz, Maia; Simmons, Alexandra D; Bagnall, Ruth Ann; Rosell, Rosemarie C

    2011-01-01

    Here we discuss the implementation of a service-learning module in two upper-division biology classes, Medical Microbiology and Cell Biology. This exciting hands-on learning experience provided our students with an opportunity to extend their learning of in-class topics to a real-life scenario. Students were required to volunteer their time (a minimum of 10 hours in a semester) at an under-served clinic in Houston, Texas. As they interacted with the personnel at the clinic, they were asked to identify the most prevalent disease (infectious for Medical Microbiology, and cellular-based for Cell) seen at the clinic and, working in groups, come up with educational material in the form of a display or brochure to be distributed to patients. The material was meant to educate patients about the disease in general terms, as well as how to recognize (symptoms), prevent and treat it. Students were required to keep a reflective journal in the form of a blog throughout the semester, and present their final materials to the class orally. Students were surveyed about their opinion of the experience at the end of the semester. The vast majority of student participants felt that the project was a positive experience and that it helped them develop additional skills beyond what they learn in the classroom and understand how lecture topics relate to every day life.

  18. Tumor microenvironment derived exosomes pleiotropically modulate cancer cell metabolism.

    Science.gov (United States)

    Zhao, Hongyun; Yang, Lifeng; Baddour, Joelle; Achreja, Abhinav; Bernard, Vincent; Moss, Tyler; Marini, Juan C; Tudawe, Thavisha; Seviour, Elena G; San Lucas, F Anthony; Alvarez, Hector; Gupta, Sonal; Maiti, Sourindra N; Cooper, Laurence; Peehl, Donna; Ram, Prahlad T; Maitra, Anirban; Nagrath, Deepak

    2016-02-27

    Cancer-associated fibroblasts (CAFs) are a major cellular component of tumor microenvironment in most solid cancers. Altered cellular metabolism is a hallmark of cancer, and much of the published literature has focused on neoplastic cell-autonomous processes for these adaptations. We demonstrate that exosomes secreted by patient-derived CAFs can strikingly reprogram the metabolic machinery following their uptake by cancer cells. We find that CAF-derived exosomes (CDEs) inhibit mitochondrial oxidative phosphorylation, thereby increasing glycolysis and glutamine-dependent reductive carboxylation in cancer cells. Through 13C-labeled isotope labeling experiments we elucidate that exosomes supply amino acids to nutrient-deprived cancer cells in a mechanism similar to macropinocytosis, albeit without the previously described dependence on oncogenic-Kras signaling. Using intra-exosomal metabolomics, we provide compelling evidence that CDEs contain intact metabolites, including amino acids, lipids, and TCA-cycle intermediates that are avidly utilized by cancer cells for central carbon metabolism and promoting tumor growth under nutrient deprivation or nutrient stressed conditions.

  19. Tumor microenvironment derived exosomes pleiotropically modulate cancer cell metabolism

    Science.gov (United States)

    Zhao, Hongyun; Yang, Lifeng; Baddour, Joelle; Achreja, Abhinav; Bernard, Vincent; Moss, Tyler; Marini, Juan C; Tudawe, Thavisha; Seviour, Elena G; San Lucas, F Anthony; Alvarez, Hector; Gupta, Sonal; Maiti, Sourindra N; Cooper, Laurence; Peehl, Donna; Ram, Prahlad T; Maitra, Anirban; Nagrath, Deepak

    2016-01-01

    Cancer-associated fibroblasts (CAFs) are a major cellular component of tumor microenvironment in most solid cancers. Altered cellular metabolism is a hallmark of cancer, and much of the published literature has focused on neoplastic cell-autonomous processes for these adaptations. We demonstrate that exosomes secreted by patient-derived CAFs can strikingly reprogram the metabolic machinery following their uptake by cancer cells. We find that CAF-derived exosomes (CDEs) inhibit mitochondrial oxidative phosphorylation, thereby increasing glycolysis and glutamine-dependent reductive carboxylation in cancer cells. Through 13C-labeled isotope labeling experiments we elucidate that exosomes supply amino acids to nutrient-deprived cancer cells in a mechanism similar to macropinocytosis, albeit without the previously described dependence on oncogenic-Kras signaling. Using intra-exosomal metabolomics, we provide compelling evidence that CDEs contain intact metabolites, including amino acids, lipids, and TCA-cycle intermediates that are avidly utilized by cancer cells for central carbon metabolism and promoting tumor growth under nutrient deprivation or nutrient stressed conditions. DOI: http://dx.doi.org/10.7554/eLife.10250.001 PMID:26920219

  20. Jasmonic acid signaling modulates ozone-induced hypersensitive cell death.

    Science.gov (United States)

    Rao, M V; Lee, H; Creelman, R A; Mullet, J E; Davis, K R

    2000-09-01

    Recent studies suggest that cross-talk between salicylic acid (SA)-, jasmonic acid (JA)-, and ethylene-dependent signaling pathways regulates plant responses to both abiotic and biotic stress factors. Earlier studies demonstrated that ozone (O(3)) exposure activates a hypersensitive response (HR)-like cell death pathway in the Arabidopsis ecotype Cvi-0. We now have confirmed the role of SA and JA signaling in influencing O(3)-induced cell death. Expression of salicylate hydroxylase (NahG) in Cvi-0 reduced O(3)-induced cell death. Methyl jasmonate (Me-JA) pretreatment of Cvi-0 decreased O(3)-induced H(2)O(2) content and SA concentrations and completely abolished O(3)-induced cell death. Cvi-0 synthesized as much JA as did Col-0 in response to O(3) exposure but exhibited much less sensitivity to exogenous Me-JA. Analyses of the responses to O(3) of the JA-signaling mutants jar1 and fad3/7/8 also demonstrated an antagonistic relationship between JA- and SA-signaling pathways in controlling the magnitude of O(3)-induced HR-like cell death.

  1. Improved film morphology reduces charge carrier recombination into the triplet excited state in a small bandgap polymer-fullerene photovoltaic cell

    NARCIS (Netherlands)

    Di Nuzzo, D.; Aguirre de Miguel, A.; Shahid, M.; Gevaerts, Veronique; Meskers, S.C.J.; Janssen, R.A.J.

    2010-01-01

    The use of diiodooctane as processing additive for construction of PCPDTBT:PCBM solar cells results in a profound change in photophysical behavior of this blend. In the improved morphology obtained with the additive, recombination of charge carriers to the lowest triplet excited state is suppressed.

  2. Calorimetric Measurement for Internal Conversion Efficiency of Photovoltaic Cells/Modules Based on Electrical Substitution Method

    Science.gov (United States)

    Saito, Terubumi; Tatsuta, Muneaki; Abe, Yamato; Takesawa, Minato

    2018-02-01

    We have succeeded in the direct measurement for solar cell/module internal conversion efficiency based on a calorimetric method or electrical substitution method by which the absorbed radiant power is determined by replacing the heat absorbed in the cell/module with the electrical power. The technique is advantageous in that the reflectance and transmittance measurements, which are required in the conventional methods, are not necessary. Also, the internal quantum efficiency can be derived from conversion efficiencies by using the average photon energy. Agreements of the measured data with the values estimated from the nominal values support the validity of this technique.

  3. Investigation of induction cells and modulator design for heavy ion accelerators

    International Nuclear Information System (INIS)

    Fong, C.G.; Reginato, L.R.

    1992-01-01

    The induction linear accelerator has been a leading candidate in the U.S. for the acceleration of high current heavy ion beams to initiate inertial confinement fusion (ICF). This paper describes the rather unique parameters derived from the accelerator beam dynamics, and addresses the design and development of accelerator induction cells and their modulators to be used in a near-term driver scaling experiment named the Induction Linac Systems Experiments (ILSE) planned for construction starting in 1994. Work is underway to develop the cells and their pulse modulators. Tradeoffs between the amorphous core material, pulse length, rise and fall time are made against efficiency, costs and technical risks are discussed

  4. Dido3 PHD Modulates Cell Differentiation and Division

    Directory of Open Access Journals (Sweden)

    Jovylyn Gatchalian

    2013-07-01

    Full Text Available Death Inducer Obliterator 3 (Dido3 is implicated in the maintenance of stem cell genomic stability and tumorigenesis. Here, we show that Dido3 regulates the expression of stemness genes in embryonic stem cells through its plant homeodomain (PHD finger. Binding of Dido3 PHD to histone H3K4me3 is disrupted by threonine phosphorylation that triggers Dido3 translocation from chromatin to the mitotic spindle. The crystal structure of Dido3 PHD in complex with H3K4me3 reveals an atypical aromatic-cage-like binding site that contains a histidine residue. Biochemical, structural, and mutational analyses of the binding mechanism identified the determinants of specificity and affinity and explained the inability of homologous PHF3 to bind H3K4me3. Together, our findings reveal a link between the transcriptional control in embryonic development and regulation of cell division.

  5. High efficiency polymer solar cells with vertically modulated nanoscale morphology

    International Nuclear Information System (INIS)

    Kumar, Ankit; Hong Ziruo; Yang Yang; Li Gang

    2009-01-01

    Nanoscale morphology has been shown to be a critical parameter governing charge transport properties of polymer bulk heterojunction (BHJ) solar cells. Recent results on vertical phase separation have intensified the research on 3D morphology control. In this paper, we intend to modify the distribution of donors and acceptors in a classical BHJ polymer solar cell by making the active layer richer in donors and acceptors near the anode and cathode respectively. Here, we chose [6,6]-phenyl- C 61 -butyric acid methyl ester (PCBM) to be the acceptor material to be thermally deposited on top of [poly(3-hexylthiophene)] P3HT: the PCBM active layer to achieve a vertical composition gradient in the BHJ structure. Here we report on a solar cell with enhanced power conversion efficiency of 4.5% which can be directly correlated with the decrease in series resistance of the device.

  6. 14th Workshop on Crystalline Silicon Solar Cells& Modules: Materials and Processes; Extended Abstracts and Papers

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B. L.

    2004-08-01

    The 14th Workshop will provide a forum for an informal exchange of technical and scientific information between international researchers in the photovoltaic and relevant non-photovoltaic fields. It will offer an excellent opportunity for researchers in private industry and at universities to prioritize mutual needs for future collaborative research. The workshop is intended to address the fundamental properties of PV silicon, new solar cell designs, advanced solar cell processing techniques, and cell-related module issues. A combination of oral presentations by invited speakers, poster sessions, and discussion sessions will review recent advances in crystal growth, new cell designs, new processes and process characterization techniques, cell fabrication approaches suitable for future manufacturing demands, and solar cell encapsulation. This year's theme, ''Crystalline Si Solar Cells: Leapfrogging the Barriers,'' reflects the continued success of crystalline Si PV in overcoming technological barriers to improve solar cell performance and lower the cost of Si PV. The workshop will consist of presentations by invited speakers, followed by discussion sessions. In addition, there will be two poster sessions presenting the latest research and development results. Some presentations will address recent technologies in the microelectronics field that may have a direct bearing on PV. The sessions will include: Advances in crystal growth and material issues; Impurities and defects; Dynamics during device processing; Passivation; High-efficiency Si solar cells; Advanced processing; Thin Si solar cells; and Solar cell reliability and module issues.

  7. Nanoscale crystallinity modulates cell proliferation on plasma sprayed surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Alan M. [School of Applied Sciences, University of Huddersfield, Huddersfield HD1 3DH (United Kingdom); Paxton, Jennifer Z.; Hung, Yi-Pei; Hadley, Martin J.; Bowen, James; Williams, Richard L. [School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT (United Kingdom); Grover, Liam M., E-mail: l.m.grover@bham.ac.uk [School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT (United Kingdom)

    2015-03-01

    Calcium phosphate coatings have been applied to the surface of metallic prostheses to mediate hard and soft tissue attachment for more than 40 years. Most coatings are formed of high purity hydroxyapatite, and coating methods are often designed to produce highly crystalline surfaces. It is likely however, that coatings of lower crystallinity can facilitate more rapid tissue attachment since the surface will exhibit a higher specific surface area and will be considerably more reactive than a comparable highly crystalline surface. Here we test this hypothesis by growing a population of MC3T3 osteoblast-like cells on the surface of two types of hip prosthesis with similar composition, but with differing crystallinity. The surfaces with lower crystallinity facilitated more rapid cell attachment and increased proliferation rate, despite having a less heterogeneous surface topography. This work highlights that the influence of the crystallinity of HA at the nano-scale is dominant over macro-scale topography for cell adhesion and growth. Furthermore, crystallinity could be easily adjusted by without compromising coating purity. These findings could facilitate designing novel coated calcium phosphate surfaces that more rapidly bond tissue following implantation. - Highlights: • Crystallinity of HA at the nano-scale was dominant over macro-scale topography. • Lower crystallinity caused rapid cell attachment and proliferation rate. • Crystallinity could be easily adjusted by without compromising coating purity.

  8. Modulation of cytokine production profiles in splenic dendritic cells ...

    African Journals Online (AJOL)

    We examined the role of splenic dendritic cells in immune response to Toxoplasma gondii infection in SAG1 (P30+) transgenic mice by investigating the kinetics of intracellular cytokines expression of IL-4, IL-10, IL-12 and IFN-γ by intracellular cytokine staining (ICS) using flow cytometry, and compared the results to those of ...

  9. Hybrid Modulation Scheme for Cascaded H-Bridge Inverter Cells ...

    African Journals Online (AJOL)

    This work proposes a switching technique for cascaded H-Bridge (CHB) cells. Single carrier Sinusoidal PWM (SCSPWM) scheme is employed in the generation of the gating signals. A sequential switching and base PWM circulation schemes are presented for this fundamental cascaded multilevel inverter topology.

  10. Modulation of collective cell behaviour by geometrical constraints

    Czech Academy of Sciences Publication Activity Database

    Lunova, M.; Zablotskyy, V.; Dempsey, N.M.; Devillers, T.; Jirsa, M.; Syková, Eva; Kubinová, Šárka; Lunov, O.; Dejneka, A.

    2016-01-01

    Roč. 8, č. 11 (2016), s. 1099-1110 ISSN 1757-9694 R&D Projects: GA MŠk(CZ) LO1309 Institutional support: RVO:68378041 Keywords : mesenchymal stem-cells * biophysical regulation * nuclear-structure Subject RIV: FP - Other Medical Disciplines Impact factor: 3.252, year: 2016

  11. Nanoscale crystallinity modulates cell proliferation on plasma sprayed surfaces

    International Nuclear Information System (INIS)

    Smith, Alan M.; Paxton, Jennifer Z.; Hung, Yi-Pei; Hadley, Martin J.; Bowen, James; Williams, Richard L.; Grover, Liam M.

    2015-01-01

    Calcium phosphate coatings have been applied to the surface of metallic prostheses to mediate hard and soft tissue attachment for more than 40 years. Most coatings are formed of high purity hydroxyapatite, and coating methods are often designed to produce highly crystalline surfaces. It is likely however, that coatings of lower crystallinity can facilitate more rapid tissue attachment since the surface will exhibit a higher specific surface area and will be considerably more reactive than a comparable highly crystalline surface. Here we test this hypothesis by growing a population of MC3T3 osteoblast-like cells on the surface of two types of hip prosthesis with similar composition, but with differing crystallinity. The surfaces with lower crystallinity facilitated more rapid cell attachment and increased proliferation rate, despite having a less heterogeneous surface topography. This work highlights that the influence of the crystallinity of HA at the nano-scale is dominant over macro-scale topography for cell adhesion and growth. Furthermore, crystallinity could be easily adjusted by without compromising coating purity. These findings could facilitate designing novel coated calcium phosphate surfaces that more rapidly bond tissue following implantation. - Highlights: • Crystallinity of HA at the nano-scale was dominant over macro-scale topography. • Lower crystallinity caused rapid cell attachment and proliferation rate. • Crystallinity could be easily adjusted by without compromising coating purity

  12. Towards the scaling up of perovskite solar cells and modules

    NARCIS (Netherlands)

    Galagan, Y.; Coenen, E.W.C.; Verhees, W.J.H.; Andriessen, R.

    2016-01-01

    A direct current (DC) simulation for perovskite solar cells with different dimensions was performed. The theoretical results demonstrate a good agreement with experimental data, indicating the reliability of the performed simulation. A theoretical model was applied for the investigation of large

  13. Parameter study for polymer solar modules based on various cell lengths and light intensities

    Energy Technology Data Exchange (ETDEWEB)

    Slooff, L.H.; Burgers, A.R.; Bende, E.E.; Kroon, J.M. [ECN Solar Energy, P.O. Box 1, 1755 ZG Petten (Netherlands); Veenstra, S.C. [ECN Solar Energy, Solliance, High Tech Campus 5, P63, 5656AE Eindhoven (Netherlands)

    2013-10-15

    Polymer solar cells may be applied in portable electronic devices, where light intensity and spectral distribution of the illuminating source can be very different compared to outdoor applications. As the power output of solar cells depends on temperature, light intensity and spectrum, the design of the module must be optimized for the specific illumination conditions in the different applications. The interconnection area between cells in a module must be as narrow as possible to maximize the active area, also called geometrical fill factor, of the module. Laser scribing has the potential to realize this. The optimal width of the interconnection zone depends both on technological limitations, e.g. laser scribe width and the minimal distance between scribes, and electrical limitations like resistive losses. The latter depends on the generated current in the cell and thus also on illumination intensity. Besides that, also the type of junction, i.e. a single or tandem junction, will influence the optimal geometry. In this paper a calculation model is presented that can be used for electrical modeling of polymer cells and modules in order to optimize the performance for the specific illumination conditions.

  14. Performance of 7-cells Dye Sensitized Solar Module in Z-type Series Interconnection

    Science.gov (United States)

    Nur Anggraini, Putri; Muliani, Lia; Maulani Nursam, Natalita; Hidayat, Jojo

    2018-01-01

    Dye sensitized solar cells (DSSC) is becoming attractive research topic as third generation solar cells technology since it provides clean energy and low cost fabrication. In this study, DSSC was fabricated into module scale, which is important for practical applications. The module was prepared in sandwich structure consisting of TiO2 working electrode and Pt counter electrode on conductive substrate with an area of 100 mm x 100 mm, which was distributed into seven active cells. TiO2 paste was deposited on FTO glass as working electrode with a size of 10 mm x 98 mm per unit cell by screen printing method. Each cell was connected in Z-type series that able to produce high voltage. I - V measurement was applied in two methods consisting of laboratory testing using sun simulator under 500 W/m2 of illumination and outdoor testing using a digital multimeter under direct sunlight. The result shows that DSSC module has photoconversion efficiency of 1.08% and 1.17% for laboratory and outdoor testing, respectively. The module was also tested in three different times to monitor its stability performance.

  15. Voiced Excitations

    National Research Council Canada - National Science Library

    Holzricher, John

    2004-01-01

    To more easily obtain a voiced excitation function for speech characterization, measurements of skin motion, tracheal tube, and vocal fold, motions were made and compared to EM sensor-glottal derived...

  16. Exciting Pools

    Science.gov (United States)

    Wright, Bradford L.

    1975-01-01

    Advocates the creation of swimming pool oscillations as part of a general investigation of mechanical oscillations. Presents the equations, procedure for deriving the slosh modes, and methods of period estimation for exciting swimming pool oscillations. (GS)

  17. Glycan Sulfation Modulates Dendritic Cell Biology and Tumor Growth

    Directory of Open Access Journals (Sweden)

    Roland El Ghazal

    2016-05-01

    Full Text Available In cancer, proteoglycans have been found to play roles in facilitating the actions of growth factors, and effecting matrix invasion and remodeling. However, little is known regarding the genetic and functional importance of glycan chains displayed by proteoglycans on dendritic cells (DCs in cancer immunity. In lung carcinoma, among other solid tumors, tumor-associated DCs play largely subversive/suppressive roles, promoting tumor growth and progression. Herein, we show that targeting of DC glycan sulfation through mutation in the heparan sulfate biosynthetic enzyme N-deacetylase/N-sulfotransferase-1 (Ndst1 in mice increased DC maturation and inhibited trafficking of DCs to draining lymph nodes. Lymphatic-driven DC migration and chemokine (CCL21-dependent activation of a major signaling pathway required for DC migration (as measured by phospho-Akt were sensitive to Ndst1 mutation in DCs. Lewis lung carcinoma tumors in mice deficient in Ndst1 were reduced in size. Purified CD11c+ cells from the tumors, which contain the tumor-infiltrating DC population, showed a similar phenotype in mutant cells. These features were replicated in mice deficient in syndecan-4, the major heparan sulfate proteoglycan expressed on the DC surface: Tumors were growth-impaired in syndecan-4–deficient mice and were characterized by increased infiltration by mature DCs. Tumors on the mutant background also showed greater infiltration by NK cells and NKT cells. These findings indicate the genetic importance of DC heparan sulfate proteoglycans in tumor growth and may guide therapeutic development of novel strategies to target syndecan-4 and heparan sulfate in cancer.

  18. Hydrogenated amorphous silicon coatings may modulate gingival cell response

    Science.gov (United States)

    Mussano, F.; Genova, T.; Laurenti, M.; Munaron, L.; Pirri, C. F.; Rivolo, P.; Carossa, S.; Mandracci, P.

    2018-04-01

    Silicon-based materials present a high potential for dental implant applications, since silicon has been proven necessary for the correct bone formation in animals and humans. Notably, the addition of silicon is effective to enhance the bioactivity of hydroxyapatite and other biomaterials. The present work aims to expand the knowledge of the role exerted by hydrogen in the biological interaction of silicon-based materials, comparing two hydrogenated amorphous silicon coatings, with different hydrogen content, as means to enhance soft tissue cell adhesion. To accomplish this task, the films were produced by plasma enhanced chemical vapor deposition (PECVD) on titanium substrates and their surface composition and hydrogen content were analyzed by means of X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectrophotometry (FTIR) respectively. The surface energy and roughness were measured through optical contact angle analysis (OCA) and high-resolution mechanical profilometry respectively. Coated surfaces showed a slightly lower roughness, compared to bare titanium samples, regardless of the hydrogen content. The early cell responses of human keratinocytes and fibroblasts were tested on the above mentioned surface modifications, in terms of cell adhesion, viability and morphometrical assessment. Films with lower hydrogen content were endowed with a surface energy comparable to the titanium surfaces. Films with higher hydrogen incorporation displayed a lower surface oxidation and a considerably lower surface energy, compared to the less hydrogenated samples. As regards mean cell area and focal adhesion density, both a-Si coatings influenced fibroblasts, but had no significant effects on keratinocytes. On the contrary, hydrogen-rich films increased manifolds the adhesion and viability of keratinocytes, but not of fibroblasts, suggesting a selective biological effect on these cells.

  19. Excited states

    CERN Document Server

    Lim, Edward C

    1974-01-01

    Excited States, Volume I reviews radiationless transitions, phosphorescence microwave double resonance through optical spectra in molecular solids, dipole moments in excited states, luminescence of polar molecules, and the problem of interstate interaction in aromatic carbonyl compounds. The book discusses the molecular electronic radiationless transitions; the double resonance techniques and the relaxation mechanisms involving the lowest triplet state of aromatic compounds; as well as the optical spectra and relaxation in molecular solids. The text also describes dipole moments and polarizab

  20. Incorporation of Biomaterials in Multicellular Aggregates Modulates Pluripotent Stem Cell Differentiation

    Science.gov (United States)

    Bratt-Leal, Andrés M.; Carpenedo, Richard L.; Ungrin, Mark; Zandstra, Peter W.; McDevitt, Todd C.

    2010-01-01

    Biomaterials are increasingly being used to engineer the biochemical and biophysical properties of the extracellular stem cell microenvironment in order to tailor niche characteristics and direct cell phenotype. To date, stem cell-biomaterial interactions have largely been studied by introducing stem cells into artificial environments, such as 2D cell culture on biomaterial surfaces, encapsulation of cell suspensions within hydrogel materials, or cell seeding on 3D polymeric scaffolds. In this study, microparticles fabricated from different materials, such as agarose, PLGA and gelatin, were stably integrated, in a dose-dependent manner, within aggregates of pluripotent stem cells (PSCs) prior to differentiation as a means to directly examine stem cell-biomaterial interactions in 3D. Interestingly, the presence of the materials within the stem cell aggregates differentially modulated the gene and protein expression patterns of several differentiation markers without adversely affecting cell viability. Microparticle incorporation within 3D stem cell aggregates can control the spatial presentation of extracellular environmental cues (i.e. soluble factors, extracellular matrix and intercellular adhesion molecules) as a means to direct the differentiation of stem cells for tissue engineering and regenerative medicine applications. In addition, these results suggest that the physical presence of microparticles within stem cell aggregates does not compromise PSC differentiation, but in fact the choice of biomaterials can impact the propensity of stem cells to adopt particular differentiated cell phenotypes. PMID:20864164

  1. Lovastatin-induced RhoA modulation and its effect on senescence in prostate cancer cells

    International Nuclear Information System (INIS)

    Lee, Jeeyun; Lee, Inkyoung; Park, Chaehwa; Kang, Won Ki

    2006-01-01

    Lovastatin inhibits a 3-hydroxy 3-methylglutaryl coenzyme A reductase and prevents the synthesis of cholesterol precursors, such as farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP), responsible for important cell signaling in cell proliferation and migration. Recently, the anti-cancer effect of lovastatin has been suggested in various tumor types. In this study, we showed that a low dose lovastatin induced senescence and G1 cell cycle arrest in human prostate cancer cells. Addition of GGPP or mevalonate, but not FPP, prevented the lovastatin-induced G1 phase cell cycle arrest and cell senescence. We found that constitutively active RhoA (caRhoA) reversed lovastatin-induced senescence in caRhoA-transfected PC-3 cells. Thus, we postulate that modulation of RhoA may be critical in lovastatin-induced senescence in PC-3 cells

  2. Gallic acid modulates phenotypic behavior and gene expression in oral squamous cell carcinoma cells by interfering with leptin pathway.

    Science.gov (United States)

    Santos, Eliane Macedo Sobrinho; da Rocha, Rogério Gonçalves; Santos, Hércules Otacílio; Guimarães, Talita Antunes; de Carvalho Fraga, Carlos Alberto; da Silveira, Luiz Henrique; Batista, Paulo Ricardo; de Oliveira, Paulo Sérgio Lopes; Melo, Geraldo Aclécio; Santos, Sérgio Henrique; de Paula, Alfredo Maurício Batista; Guimarães, André Luiz Sena; Farias, Lucyana Conceição

    2018-01-01

    Gallic acid is a polyphenolic compost appointed to interfere with neoplastic cells behavior. Evidence suggests an important role of leptin in carcinogenesis pathways, inducing a proliferative phenotype. We investigated the potential of gallic acid to modulate leptin-induced cell proliferation and migration of oral squamous cell carcinoma cell lines. The gallic acid effect on leptin secretion by oral squamous cell carcinoma cells, as well as the underlying molecular mechanisms, was also assessed. For this, we performed proliferation, migration, immunocytochemical and qPCR assays. The expression levels of cell migration-related genes (MMP2, MMP9, Col1A1, and E-cadherin), angiogenesis (HIF-1α, mir210), leptin signaling (LepR, p44/42 MAPK), apoptosis (casp-3), and secreted leptin levels by oral squamous cell carcinoma cells were also measured. Gallic acid decreased proliferation and migration of leptin-treated oral squamous cell carcinoma cells, and reduced mRNA expression of MMP2, MMP9, Col1A1, mir210, but did not change HIF-1α. Gallic acid decreased levels of leptin secreted by oral squamous cell carcinoma cells, accordingly with downregulation of p44/42 MAPK expression. Thus, gallic acid appears to break down neoplastic phenotype of oral squamous cell carcinoma cells by interfering with leptin pathway. Copyright © 2017 Elsevier GmbH. All rights reserved.

  3. Detection and Interpretation of Fluorescence Signals Generated by Excitable Cells and Tissues

    Science.gov (United States)

    Costantino, Anthony J.

    Part 1: High-Sensitivity Amplifiers for Detecting Fluorescence . Monitoring electrical activity and Cai 2+ transients in biological tissues and individual cells increasingly utilizes optical sensors based on voltage-dependent and Cai 2+-dependent fluorescent dyes. However, achieving satisfactory signal-to-noise ratios (SNR) often requires increased illumination intensities and/or dye concentrations, which results in photo-toxicity, photo-bleaching and other adverse effects limiting the utility of optical recordings. The most challenging are the recordings from individual cardiac myocytes and neurons. Here we demonstrate that by optimizing a conventional transimpedance topology one can achieve a 10-20 fold increase of sensitivity with photodiode-based recording systems (dependent on application). We provide a detailed comparative analysis of the dynamic and noise characteristics of different transimpedance amplifier topologies as well as the example(s) of their practical implementation. Part 2: Light-Scattering Models for Interpretation of Fluorescence Data. Current interest in understanding light transport in cardiac tissue has been motivated in part by increased use of voltage-sensitive and Ca i2+-sensitive fluorescent probes to map electrical impulse propagation and Cai2+-transients in the heart. The fluorescent signals are recorded using such probes represent contributions from different layers of myocardial tissue and are greatly affected by light scattering. The interpretation of these signals thus requires deconvolution which would not be possible without detailed models of light transport in the respective tissue. Which involves the experimental measurements of the absorption, scattering, and anisotropy coefficients, mua, mu s, and g respectively. The aim of the second part of our thesis was to derive a new method for deriving these parameters from high spatial resolution measurements of forward-directed flux (FDF). To this end, we carried out high spatial

  4. Theory of modulational interaction of trapped ion convective cells and drift wave turbulence

    International Nuclear Information System (INIS)

    Shapiro, V.D.; Diamond, P.H.; Lebedev, V.; Soloviev, G.; Shevchenko, V.

    1993-01-01

    Theoretical and computational studies of the modulational interaction between trapped ion convective cells and short wavelength drift wave turbulence are discussed. These studies are motivated by the fact that cells and drift waves are expected to coexist in tokamaks so that: (a) cells strain and modulate drift waves, and (b) drift waves open-quote ride on close-quote a background of cells. The results of the authors' investigation indicate that: (1) (nonlinear) parametric growth rates of trapped ion convective cells can exceed linear predictions (for drift wave levels at the mixing length limit); (2) a set of coupled envelope equations, akin to the Zakharov equations from Langmuir turbulence, can be derived and used to predict the formation of a dipole pair of convective cells trapped by the drift wave envelope. This dipole pair is strongly anisotropic, due to the structure of the drift wave Reynolds stress which drives the cell flow. Numerical solutions of the envelope equations are in good agreement with theoretical predictions, and indicate the persistence of the structure in time; (3) strong modulation and trapping of drift waves with k perpendicular ρ > 1 occurs. Extensions to magnetically sheared systems and the broader implications of this work as a paradigm for the dynamics of persistent structures in shearing flows are discussed

  5. Uremia modulates the phenotype of aortic smooth muscle cells

    DEFF Research Database (Denmark)

    Madsen, Marie; Pedersen, Annemarie Aarup; Albinsson, Sebastian

    2017-01-01

    the phenotype of aortic SMCs in vivo. METHODS: Moderate uremia was induced by 5/6 nephrectomy in apolipoprotein E knockout (ApoE(-/-)) and wildtype C57Bl/6 mice. Plasma analysis, gene expression, histology, and myography were used to determine uremia-mediated changes in the arterial wall. RESULTS: Induction...... of moderate uremia in ApoE(-/-) mice increased atherosclerosis in the aortic arch en face 1.6 fold (p = 0.04) and induced systemic inflammation. Based on histological analyses of aortic root sections, uremia increased the medial area, while there was no difference in the content of elastic fibers or collagen...... in the aortic media. In the aortic arch, mRNA and miRNA expression patterns were consistent with a uremia-mediated phenotypic modulation of SMCs; e.g. downregulation of myocardin, α-smooth muscle actin, and transgelin; and upregulation of miR146a. Notably, these expression patterns were observed after acute (2...

  6. Alterations in integrin expression modulates invasion of pancreatic cancer cells.

    LENUS (Irish Health Repository)

    Walsh, Naomi

    2009-01-01

    BACKGROUND: Factors mediating the invasion of pancreatic cancer cells through the extracellular matrix (ECM) are not fully understood. METHODS: In this study, sub-populations of the human pancreatic cancer cell line, MiaPaCa-2 were established which displayed differences in invasion, adhesion, anoikis, anchorage-independent growth and integrin expression. RESULTS: Clone #3 displayed higher invasion with less adhesion, while Clone #8 was less invasive with increased adhesion to ECM proteins compared to MiaPaCa-2. Clone #8 was more sensitive to anoikis than Clone #3 and MiaPaCa-2, and displayed low colony-forming efficiency in an anchorage-independent growth assay. Integrins beta 1, alpha 5 and alpha 6 were over-expressed in Clone #8. Using small interfering RNA (siRNA), integrin beta1 knockdown in Clone #8 cells increased invasion through matrigel and fibronectin, increased motility, decreased adhesion and anoikis. Integrin alpha 5 and alpha 6 knockdown also resulted in increased motility, invasion through matrigel and decreased adhesion. CONCLUSION: Our results suggest that altered expression of integrins interacting with different extracellular matrixes may play a significant role in suppressing the aggressive invasive phenotype. Analysis of these clonal populations of MiaPaCa-2 provides a model for investigations into the invasive properties of pancreatic carcinoma.

  7. Depth profiling of thin film solar cell components by synchrotron excited Soft X-ray emission spectroscopy (SXES)

    Energy Technology Data Exchange (ETDEWEB)

    Moenig, Harry; Grimm, Alexander; Lux-Steiner, Martha; Saez-Araoz, Rodrigo; Fischer, Christian-Herbert [Freie Universitaet Berlin (Germany); Baer, Markus [University of Las Vegas (United States); Camus, Christian; Ennaoui, Ahmed; Kaufmann, Christian; Koerber, Paul; Kropp, Timo; Lauermann, Iver; Lehmann, Sebastian; Muenchenberg, Tim; Pistor, Paul; Puttnins, Stefan; Schock, Hans-Werner; Sokoll, Stefan [Hahn-Meitner-Institut Berlin (Germany); Jung, Christian [BESSY GmbH Berlin (Germany)

    2007-07-01

    Depending on the elemental composition of a material, SXES provides an information depth of 50-1000 nm. For studies of thin multilayer structures tuning of this parameter is highly desirable. One possibility is the variation of the excitation energy, which is accompanied by variation of photoionisation cross sections. Alternatively, we performed angle resolved SXES on the solar cell absorber material Cu(In,Ga)Se{sub 2} covered by CdS or Zn(S,O) buffer layers (10-50 nm). Due to our setup geometry, the emission spectra clearly display increased surface sensitivity at small (grazing exit) and large (grazing incidence) exit angles. A model based on Beer-Lamberts law and setup geometry is in reasonable agreement with our experimental data.The presented results show that angle resolved SXES measurements yield depth-dependent information on multilayer structures. The increased surface sensitivity at grazing exit and grazing incidence angles allows the detection of extremely thin cover layers at reasonable recording times.

  8. Resonance Raman and excitation energy dependent charge transfer mechanism in halide-substituted hybrid perovskite solar cells.

    Science.gov (United States)

    Park, Byung-wook; Jain, Sagar M; Zhang, Xiaoliang; Hagfeldt, Anders; Boschloo, Gerrit; Edvinsson, Tomas

    2015-02-24

    Organo-metal halide perovskites (OMHPs) are materials with attractive properties for optoelectronics. They made a recent introduction in the photovoltaics world by methylammonium (MA) lead triiodide and show remarkably improved charge separation capabilities when chloride and bromide are added. Here we show how halide substitution in OMHPs with the nominal composition CH3NH3PbI2X, where X is I, Br, or Cl, influences the morphology, charge quantum yield, and local interaction with the organic MA cation. X-ray diffraction and photoluminescence data demonstrate that halide substitution affects the local structure in the OMHPs with separate MAPbI3 and MAPbCl3 phases. Raman spectroscopies as well as theoretical vibration calculations reveal that this at the same time delocalizes the charge to the MA cation, which can liberate the vibrational movement of the MA cation, leading to a more adaptive organic phase. The resonance Raman effect together with quantum chemical calculations is utilized to analyze the change in charge transfer mechanism upon electronic excitation and gives important clues for the mechanism of the much improved photovoltage and photocurrent also seen in the solar cell performance for the materials when chloride compounds are included in the preparation.

  9. Oxygen Modulates Human Decidual Natural Killer Cell Surface Receptor Expression and Interactions with Trophoblasts1

    Science.gov (United States)

    Wallace, Alison E.; Goulwara, Sonu S.; Whitley, Guy S.; Cartwright, Judith E.

    2014-01-01

    Decidual natural killer (dNK) cells have been shown to both promote and inhibit trophoblast behavior important for decidual remodeling in pregnancy and have a distinct phenotype compared to peripheral blood NK cells. We investigated whether different levels of oxygen tension, mimicking the physiological conditions of the decidua in early pregnancy, altered cell surface receptor expression and activity of dNK cells and their interactions with trophoblast. dNK cells were isolated from terminated first-trimester pregnancies and cultured in oxygen tensions of 3%, 10%, and 21% for 24 h. Cell surface receptor expression was examined by flow cytometry, and the effects of secreted factors in conditioned medium (CM) on the trophoblast cell line SGHPL-4 were assessed in vitro. SGHPL-4 cells treated with dNK cell CM incubated in oxygen tensions of 10% were significantly more invasive (P cells treated with dNK cell CM incubated in oxygen tensions of 3% or 21%. After 24 h, a lower percentage of dNK cells expressed CD56 at 21% oxygen (P cells expressed NKG2D at 10% oxygen (P oxygen tensions, with large patient variation. This study demonstrates dNK cell phenotype and secreted factors are modulated by oxygen tension, which induces changes in trophoblast invasion and endovascular-like differentiation. Alterations in dNK cell surface receptor expression and secreted factors at different oxygen tensions may represent regulation of function within the decidua during the first trimester of pregnancy. PMID:25232021

  10. Low concentrations of the solvent dimethyl sulphoxide alter intrinsic excitability properties of cortical and hippocampal pyramidal cells.

    Directory of Open Access Journals (Sweden)

    Francesco Tamagnini

    Full Text Available Dimethylsulfoxide (DMSO is a widely used solvent in biology. It has many applications perhaps the most common of which is in aiding the preparation of drug solutions from hydrophobic chemical entities. Recent studies have suggested that this molecule may be able to induce apoptosis in neural tissues urging caution regarding its introduction into humans, for example as part of stem cell transplants. Here we have used in vitro electrophysiological methods applied to murine brain slices to examine whether a few hours treatment with 0.05% DMSO (a concentration regarded by many as innocuous alters intrinsic excitability properties of neurones. We investigated pyramidal neurones in two distinct brain regions, namely area CA1 of the hippocampus and layer 2 of perirhinal cortex. In the former there was no effect on resting potential but input resistance was decreased by DMSO pre-treatment. In line with this action potential count for any level of depolarizing current stimulus was reduced by ∼25% following DMSO treatment. Ih-mediated "sag" was also increased in CA1 pyramids and action potential waveform analysis demonstrated that DMSO treatment moved action potential threshold towards resting potential. In perirhinal cortex a decreased action potential output for various depolarizing current stimuli was also seen. In these cells action potential threshold was unaltered by DMSO but a significant increase in action potential width was apparent. These data indicate that pre-treatment with this widely employed solvent can elicit multifaceted neurophysiological changes in mammalian neurones at concentrations below those frequently encountered in the published literature.

  11. Lactobacillus crispatus Modulates Vaginal Epithelial Cell Innate Response to Candida albicans

    Directory of Open Access Journals (Sweden)

    Xiao-Xi Niu

    2017-01-01

    Conclusions: L. crispatus can attenuate the virulence of C. albicans, modulate the secretion of cytokines and chemokines, and enhance the immune response of VK2/E6E7 cells in vitro. The vaginal mucosa has a potential function in the local immune responses against pathogens that can be promoted by L. crispatus.

  12. TH1 and TH2 cell polarization increases with aging and is modulated by zinc supplementation

    OpenAIRE

    2008-01-01

    TH1 and TH2 cell polarization increases with aging and is modulated by zinc supplementation correspondence: Corresponding author. Tel.: +49 241 8080208; fax: +49 241 8082613. (Rink, Lothar) (Rink, Lothar) Institute of Immunology, University Hospital, RWTH Aachen University - Aachen--> - GERMANY (Uciechowski, Peter) Institute of Immunology, University Hospital, RWTH Aachen University - Aachen--> - GERMAN...

  13. Identification of Lactobacillus plantarum genes modulating the cytokine response of human peripheral blood mononuclear cells

    NARCIS (Netherlands)

    van Hemert, Saskia; Meijerink, Marjolein; Molenaar, Douwe; Bron, Peter A.; de Vos, Paul; Kleerebezem, Michiel; Wells, Jerry M.; Marco, Maria L.

    2010-01-01

    Background: Modulation of the immune system is one of the most plausible mechanisms underlying the beneficial effects of probiotic bacteria on human health. Presently, the specific probiotic cell products responsible for immunomodulation are largely unknown. In this study, the genetic and phenotypic

  14. Edge sealing for low cost stability enhancement of roll-to-roll processed flexible polymer solar cell modules

    DEFF Research Database (Denmark)

    Tanenbaum, David M.; Dam, Henrik Friis; Rösch, R.

    2012-01-01

    Fully roll-to-roll processed polymer solar cell modules were prepared, characterized, and laminated. Cell modules were cut from the roll and matched pairs were selected, one module with exposed cut edges, the other laminated again with the same materials and adhesive sealing fully around the cut...... edges. The edge sealing rim was 10 mm wide. Cell modules were characterized by periodic measurements of IV curves over extended periods in a variety of conditions, as well as by a variety of spatial imaging techniques. Data show significant stability benefits of the edge sealing process. The results...

  15. Dopamine receptors on adrenal chromaffin cells modulate calcium uptake and catecholamine release

    Energy Technology Data Exchange (ETDEWEB)

    Bigornia, L; Suozzo, M; Ryan, K A; Napp, D; Schneider, A S

    1988-10-01

    The presence of dopamine-containing cells in sympathetic ganglia, i.e., small, intensely fluorescent cells, has been known for some time. However, the role of dopamine as a peripheral neurotransmitter and its mechanism of action are not well understood. Previous studies have demonstrated the presence of D2 dopamine receptors on the surface of bovine adrenal chromaffin cells using radioligand binding methods and dopamine receptor inhibition of catecholamine release from perfused adrenal glands. In the present study, we provide evidence confirming a role of dopamine receptors as inhibitory modulators of adrenal catecholamine release from bovine chromaffin cell cultures and further show that the mechanism of modulation involves inhibition of stimulated calcium uptake. Apomorphine gave a dose-dependent inhibition (IC50 = 1 microM) of 45Ca2+ uptake stimulated by either nicotine (10 microM) or membrane depolarization with an elevated K+ level (60 mM). This inhibition was reversed by a series of specific (including stereospecific) dopamine receptor antagonists: haloperidol, spiperone, sulpiride, and (+)-butaclamol, but not (-)-butaclamol. In addition, the calcium channel agonist Bay K 8644 was used to stimulate uptake of 45Ca2+ into chromaffin cells, and this uptake was also inhibited by the dopamine receptor agonist apomorphine. The combined results suggest that dopamine receptors on adrenal chromaffin cells alter Ca2+ channel conductance, which, in turn, modulates catecholamine release.

  16. Generator module architecture for a large solid oxide fuel cell power plant

    Science.gov (United States)

    Gillett, James E.; Zafred, Paolo R.; Riggle, Matthew W.; Litzinger, Kevin P.

    2013-06-11

    A solid oxide fuel cell module contains a plurality of integral bundle assemblies, the module containing a top portion with an inlet fuel plenum and a bottom portion receiving air inlet feed and containing a base support, the base supports dense, ceramic exhaust manifolds which are below and connect to air feed tubes located in a recuperator zone, the air feed tubes passing into the center of inverted, tubular, elongated, hollow electrically connected solid oxide fuel cells having an open end above a combustion zone into which the air feed tubes pass and a closed end near the inlet fuel plenum, where the fuel cells comprise a fuel cell stack bundle all surrounded within an outer module enclosure having top power leads to provide electrical output from the stack bundle, where the fuel cells operate in the fuel cell mode and where the base support and bottom ceramic air exhaust manifolds carry from 85% to all 100% of the weight of the stack, and each bundle assembly has its own control for vertical and horizontal thermal expansion control.

  17. Hop/STI1 modulates retinal proliferation and cell death independent of PrPC

    International Nuclear Information System (INIS)

    Arruda-Carvalho, Maithe; Njaine, Brian; Silveira, Mariana S.; Linden, Rafael; Chiarini, Luciana B.

    2007-01-01

    Hop/STI1 is a co-chaperone adaptor protein for Hsp70/Hsp90 complexes. Hop/STI1 is found extracellularly and modulates cell death and differentiation through interaction with the prion protein (PrP C ). Here, we investigated the expression of hop/STI1 and its role upon cell proliferation and cell death in the developing retina. Hop/STI1 is more expressed in developing rat retina than in the mature tissue. Hop/STI1 blocks retinal cell death in the neuroblastic layer (NBL) in a PrP C dependent manner, but failed to protect ganglion cells against axotomy-induced cell death. An antibody raised against hop/STI1 (α-STI1) blocked both ganglion cell and NBL cell death independent of PrP C . cAMP/PKA, ERK, PI3K and PKC signaling pathways were not involved in these effects. Hop/STI1 treatment reduced proliferation, while α-STI1 increased proliferation in the developing retina, both independent of PrP C . We conclude that hop/STI1 can modulate both proliferation and cell death in the developing retina independent of PrP C

  18. Heparin modulates human intestinal smooth muscle (HISM) cell proliferation and matrix production

    International Nuclear Information System (INIS)

    Graham, M.; Perr, H.; Drucker, D.E.; Diegelmann, R.F.

    1986-01-01

    (HISM) cell proliferation and collagen production may play a role in the pathogenesis of intestinal stricture in Crohn's disease. The present studies were performed to evaluate the effects of heparin, a known modulator of vascular smooth muscle cells, on HISM cell proliferation and collagen production. Heparin (100 μg/ml) was added daily to HISM cell cultures for cell proliferation studies and for 24 hours at various time points during culture for collagen synthesis studies. Collagen synthesis was determined by the uptake of 3 H proline into collagenase-sensitive protein. Heparin completely inhibited cell proliferation for 7 days, after which cell numbers increased but at a slower rate than controls. Cells released from heparin inhibition demonstrated catch-up growth to control levels. Collagen production was significantly inhibited by 24 hours exposure to heparin but only at those times during culture when collagen synthesis was maximal (8 to 12 days). Non-collagen protein synthesis was inhibited by heparin at all time points during culture. Heparin through its modulation of HISM cells may play an important role in the control of the extracellular matrix of the intestinal wall

  19. The histone deacetylase inhibitor Trichostatin A modulates CD4+ T cell responses

    Directory of Open Access Journals (Sweden)

    Moreira José

    2003-11-01

    Full Text Available Abstract Background Histone deacetylase inhibitors (HDACIs induce hyperacetylation of core histones modulating chromatin structure and affecting gene expression. These compounds are also able to induce growth arrest, cell differentiation, and apoptotic cell death of tumor cells in vitro as well as in vivo. Even though several genes modulated by HDAC inhibition have been identified, those genes clearly responsible for the biological effects of these drugs have remained elusive. We investigated the pharmacological effect of the HDACI and potential anti-cancer agent Trichostatin A (TSA on primary T cells. Methods To ascertain the effect of TSA on resting and activated T cells we used a model system where an enriched cell population consisting of primary T-cells was stimulated in vitro with immobilized anti-CD3/anti-CD28 antibodies whilst exposed to pharmacological concentrations of Trichostatin A. Results We found that this drug causes a rapid decline in cytokine expression, accumulation of cells in the G1 phase of the cell cycle, and induces apoptotic cell death. The mitochondrial respiratory chain (MRC plays a critical role in the apoptotic response to TSA, as dissipation of mitochondrial membrane potential and reactive oxygen species (ROS scavengers block TSA-induced T-cell death. Treatment of T cells with TSA results in the altered expression of a subset of genes involved in T cell responses, as assessed by microarray gene expression profiling. We also observed up- as well as down-regulation of various costimulatory/adhesion molecules, such as CD28 and CD154, important for T-cell function. Conclusions Taken together, our findings indicate that HDAC inhibitors have an immunomodulatory potential that may contribute to the potency and specificity of these antineoplastic compounds and might be useful in the treatment of autoimmune disorders.

  20. THE THIOREDOXIN SYSTEM IN REGULATING MCF-7 CELL PROLIFERATION UNDER REDOX STATUS MODULATION

    Directory of Open Access Journals (Sweden)

    E. A. Stepovaya

    2016-01-01

    Full Text Available Introduction. Despite the available data on tumor cell functioning under the conditions of free radical-mediated oxidation, the mechanisms of redox regulation, cell proliferation management and apoptosis avoidance remain understudied.The objective of the study was to identify the role of the thioredoxin system in regulating MCF-7 breast cancer cell proliferation under redox status modulation with 1.4-dithioerythritol.Material and methods. The studies were conducted on the MCF-7 breast cancer cell line, grown in adherent cell culture. Cell redox status was modulated with5 mM N-ethylmaleimide – an SH group and peptide inhibitor and5 mM 1.4-dithioerythritol – a thiol group protector. The cell cycle was evaluated by flow cytometry, the same technique was used to measure the reactive oxygen species concentration. The levels of reduced and oxidized glutathione and the activity of thioredoxin reductase were identified by spectrophotometry. The intracellular concentrations of thioredoxin, cyclin E and cyclin-dependent kinase 2 were determined by Western blot analysis.Results and discussion. The essential role of the thioredoxin system in regulating MCF-7 breast cancer cell proliferation was exhibited. S-phase arrest under the effect of N-ethylmaleimide and G0/G1-phase arrest under the effect of 1.4-dithioerythritol are associated with the changes in the activity of redox-sensitive protein complexes (cyclins and cyclin-dependent kinases that regulate cell proliferation.Conclusion. Redoxdependent modulation of proliferation regulating intracellular protein activity occurs due to the thioredoxin system. This is a promising research area for seeking molecular targets of breast cell malignization. 

  1. Leukemia Mediated Endothelial Cell Activation Modulates Leukemia Cell Susceptibility to Chemotherapy through a Positive Feedback Loop Mechanism.

    Directory of Open Access Journals (Sweden)

    Bahareh Pezeshkian

    Full Text Available In acute myeloid leukemia (AML, the chances of achieving disease-free survival are low. Studies have demonstrated a supportive role of endothelial cells (ECs in normal hematopoiesis. Here we show that similar intercellular relationships exist in leukemia. We demonstrate that leukemia cells themselves initiate these interactions by directly modulating the behavior of resting ECs through the induction of EC activation. In this inflammatory state, activated ECs induce the adhesion of a sub-set of leukemia cells through the cell adhesion molecule E-selectin. These adherent leukemia cells are sequestered in a quiescent state and are unaffected by chemotherapy. The ability of adherent cells to later detach and again become proliferative following exposure to chemotherapy suggests a role of this process in relapse. Interestingly, differing leukemia subtypes modulate this process to varying degrees, which may explain the varied response of AML patients to chemotherapy and relapse rates. Finally, because leukemia cells themselves induce EC activation, we postulate a positive-feedback loop in leukemia that exists to support the growth and relapse of the disease. Together, the data defines a new mechanism describing how ECs and leukemia cells interact during leukemogenesis, which could be used to develop novel treatments for those with AML.

  2. Olfactory bulb short axon cell release of GABA and dopamine produces a temporally biphasic inhibition-excitation response in external tufted cells.

    Science.gov (United States)

    Liu, Shaolin; Plachez, Celine; Shao, Zuoyi; Puche, Adam; Shipley, Michael T

    2013-02-13

    Evidence for coexpression of two or more classic neurotransmitters in neurons has increased, but less is known about cotransmission. Ventral tegmental area (VTA) neurons corelease dopamine (DA), the excitatory transmitter glutamate, and the inhibitory transmitter GABA onto target cells in the striatum. Olfactory bulb (OB) short axon cells (SACs) form interglomerular connections and coexpress markers for DA and GABA. Using an optogenetic approach, we provide evidence that mouse OB SACs release both GABA and DA onto external tufted cells (ETCs) in other glomeruli. Optical activation of channelrhodopsin specifically expressed in DAergic SACs produced a GABA(A) receptor-mediated monosynaptic inhibitory response, followed by DA-D(1)-like receptor-mediated excitatory response in ETCs. The GABA(A) receptor-mediated hyperpolarization activates I(h) current in ETCs; synaptically released DA increases I(h), which enhances postinhibitory rebound spiking. Thus, the opposing actions of synaptically released GABA and DA are functionally integrated by I(h) to generate an inhibition-to-excitation "switch" in ETCs. Consistent with the established role of I(h) in ETC burst firing, we show that endogenous DA release increases ETC spontaneous bursting frequency. ETCs transmit sensory signals to mitral/tufted output neurons and drive intraglomerular inhibition to shape glomerulus output to downstream olfactory networks. GABA and DA cotransmission from SACs to ETCs may play a key role in regulating output coding across the glomerular array.

  3. Solar-cell interconnect design for terrestrial photovoltaic modules

    Science.gov (United States)

    Mon, G. R.; Moore, D. M.; Ross, R. G., Jr.

    1984-01-01

    Useful solar cell interconnect reliability design and life prediction algorithms are presented, together with experimental data indicating that the classical strain cycle (fatigue) curve for the interconnect material does not account for the statistical scatter that is required in reliability predictions. This shortcoming is presently addressed by fitting a functional form to experimental cumulative interconnect failure rate data, which thereby yields statistical fatigue curves enabling not only the prediction of cumulative interconnect failures during the design life of an array field, but also the quantitative interpretation of data from accelerated thermal cycling tests. Optimal interconnect cost reliability design algorithms are also derived which may allow the minimization of energy cost over the design life of the array field.

  4. Mechanisms of ROS modulated cell survival during carcinogenesis.

    Science.gov (United States)

    Clerkin, J S; Naughton, R; Quiney, C; Cotter, T G

    2008-07-18

    There is increasing evidence within the literature that the decreased susceptibility of tumour cells to stimuli that induce apoptosis can be linked to their inherently increased redox potential. The review primarily focuses on the PI3-kinase/Akt pathway, and the multiple points along this signalling pathway that may be redox regulated. The PI3-kinase/Akt pathway can influence a cells' sensitivity to death inducing signals, through direct manipulation of apoptosis regulating molecules or by regulating the activity of key transcription factors. Proteins involved in the control of apoptosis that are directly regulated by the PI3-kinase/Akt pathway include caspase-9, Bad and the transcription factor GSK-3beta. Lately, it is becoming increasingly obvious that phosphatases are a major counter balance to the PI3-kinase/Akt pathway. Phosphatases such as PP2A and PP1alpha can dephosphorylate signalling molecules within the PI3-kinase/Akt pathway, blocking their activity. It is the balance between the kinase activity and the phosphatase activity that determines the presence and strength of the PI3-kinase/Akt signal. This is why any protein modifications that hinder dephosphorylation can increase the tumours survival advantage. One such modification is the oxidation of the sulphydryl group in key cysteine residues present within the active site of the phosphatases. This highlights the link between the increased redox stress in tumours with the PI3-kinase/Akt pathway. This review will discuss the various sources of reactive oxygen species within a tumour and the effect of these radicals on the PI3-kinase/Akt pathway.

  5. Behavior of the potential-induced degradation of photovoltaic modules fabricated using flat mono-crystalline silicon cells with different surface orientations

    Science.gov (United States)

    Yamaguchi, Seira; Masuda, Atsushi; Ohdaira, Keisuke

    2016-04-01

    This paper deals with the dependence of the potential-induced degradation (PID) of flat, p-type mono-crystalline silicon solar cell modules on the surface orientation of solar cells. The investigated modules were fabricated from p-type mono-crystalline silicon cells with a (100) or (111) surface orientation using a module laminator. PID tests were performed by applying a voltage of -1000 V to shorted module interconnector ribbons with respect to an Al plate placed on the cover glass of the modules at 85 °C. A decrease in the parallel resistance of the (100)-oriented cell modules is more significant than that of the (111)-oriented cell modules. Hence, the performance of the (100)-oriented-cell modules drastically deteriorates, compared with that of the (111)-oriented-cell modules. This implies that (111)-oriented cells offer a higher PID resistance.

  6. Dopamine receptors modulate cytotoxicity of natural killer cells via cAMP-PKA-CREB signaling pathway.

    Directory of Open Access Journals (Sweden)

    Wei Zhao

    Full Text Available Dopamine (DA, a neurotransmitter in the nervous system, has been shown to modulate immune function. We have previously reported that five subtypes of DA receptors, including D1R, D2R, D3R, D4R and D5R, are expressed in T lymphocytes and they are involved in regulation of T cells. However, roles of these DA receptor subtypes and their coupled signal-transduction pathway in modulation of natural killer (NK cells still remain to be clarified. The spleen of mice was harvested and NK cells were isolated and purified by negative selection using magnetic activated cell sorting. After NK cells were incubated with various drugs for 4 h, flow cytometry measured cytotoxicity of NK cells against YAC-1 lymphoma cells. NK cells expressed the five subtypes of DA receptors at mRNA and protein levels. Activation of D1-like receptors (including D1R and D5R with agonist SKF38393 enhanced NK cell cytotoxicity, but activation of D2-like receptors (including D2R, D3R and D4R with agonist quinpirole attenuated NK cells. Simultaneously, SKF38393 elevated D1R and D5R expression, cAMP content, and phosphorylated cAMP-response element-binding (CREB level in NK cells, while quinpirole reduced D3R and D4R expression, cAMP content, and phosphorylated CREB level in NK cells. These effects of SKF38393 were blocked by SCH23390, an antagonist of D1-like receptors, and quinpirole effects were abolished by haloperidol, an antagonist of D2-like receptors. In support these results, H89, an inhibitor of phosphokinase A (PKA, prevented the SKF38393-dependent enhancement of NK cells and forskolin, an activator of adenylyl cyclase (AC, counteracted the quinpirole-dependent suppression of NK cells. These findings show that DA receptor subtypes are involved in modulation of NK cells and suggest that D1-like receptors facilitate NK cells by stimulating D1R/D5R-cAMP-PKA-CREB signaling pathway and D2-like receptors suppress NK cells by inhibiting D3R/D4R-cAMP-PKA-CREB signaling pathway. The

  7. Differential Modulation of Transcription Factors and Cytoskeletal Proteins in Prostate Carcinoma Cells by a Bacterial Lactone

    Directory of Open Access Journals (Sweden)

    Senthil R. Kumar

    2018-01-01

    Full Text Available The present study tested the effect of a bacterial lactone N-(3-oxododecanoyl-homoserine lactone (C12-HSL on the cytoskeletal and transcriptional genes and proteins in prostate adenocarcinoma (PA cells (DU145 and LNCaP and prostate small cell neuroendocrine carcinoma (SCNC PC3 cells including their cellular viability and apoptosis. Our data indicate that cell migration and colony formation were affected in the presence of C12-HSL. C12-HSL induced apoptosis and altered viability of both PA and SCNC cells in a concentration dependent manner as measured by fluorescence and chemiluminescence assays. Compared to PCa cells, noncancerous prostate epithelial cells (RWPE1 were resistant to modification by C12-HSL. Further, the viability of PC3 cells in 3D matrix was suppressed by C12-HSL treatment as detected using calcein AM fluorescence in situ. C12-HSL treatment induced cytoskeletal associated protein expression of vinculin and RhoC, which may have implications in cancer cell motility, adhesion, and metastasis. IQGAP protein expression was reduced in DU145 and RWPE1 cells in the presence of C12-HSL. C12-HSL decreased STAT3 phosphorylation in DU145 cells but increased STAT1 protein phosphorylation in PC3 and LNCaP cells. Overall, these studies indicate that C12-HSL can trigger changes in transcription factors and cytoskeletal proteins and thereby modulate growth and migration properties of PCa cells.

  8. Excited fermions

    International Nuclear Information System (INIS)

    Boudjema, F.; Djouadi, A.; Kneur, J.L.

    1992-01-01

    The production of excited fermions with mass above 100 GeV is considered. f→Vf (1) decay widths are calculated where V=γ, Z or W. Excited fermion pair production in e + e - annihilation and in γγ collisions, and single production in e + e - annihilation, eγ and γγ collisions is also discussed. Cross sections are calculated for all these cases. The discovery potential of the NLC at 500 GeV is compared with that of other colliders. (K.A.) 15 refs., 5 figs., 2 tabs

  9. Collectin-11 Is an Important Modulator of Retinal Pigment Epithelial Cell Phagocytosis and Cytokine Production.

    Science.gov (United States)

    Dong, Xia; Wu, Weiju; Ma, Liang; Liu, Chengfei; Bhuckory, Mohajeet B; Wang, Liping; Nandrot, Emeline F; Xu, Heping; Li, Ke; Liu, Yizhi; Zhou, Wuding

    2017-01-01

    In this paper, we report previously unknown roles for collectin-11 (CL-11, a soluble C-type lectin) in modulating the retinal pigment epithelial (RPE) cell functions of phagocytosis and cytokine production. We found that CL-11 and its carbohydrate ligand are expressed in both the murine and human neural retina; these resemble each other in terms of RPE and photoreceptor cells. Functional analysis of murine RPE cells showed that CL-11 facilitates the opsonophagocytosis of photoreceptor outer segments and apoptotic cells, and also upregulates IL-10 production. Mechanistic analysis revealed that calreticulin on the RPE cells is required for CL-11-mediated opsonophagocytosis whereas signal-regulatory protein α and mannosyl residues on the cells are involved in the CL-11-mediated upregulation of IL-10 production. This study is the first to demonstrate the role of CL-11 and the molecular mechanisms involved in modulating RPE cell phagocytosis and cytokine production. It provides a new insight into retinal health and disease and has implications for other phagocytic cells. © 2017 S. Karger AG, Basel.

  10. Glucose impairs tamoxifen responsiveness modulating connective tissue growth factor in breast cancer cells.

    Science.gov (United States)

    Ambrosio, Maria Rosaria; D'Esposito, Vittoria; Costa, Valerio; Liguoro, Domenico; Collina, Francesca; Cantile, Monica; Prevete, Nella; Passaro, Carmela; Mosca, Giusy; De Laurentiis, Michelino; Di Bonito, Maurizio; Botti, Gerardo; Franco, Renato; Beguinot, Francesco; Ciccodicola, Alfredo; Formisano, Pietro

    2017-12-12

    Type 2 diabetes and obesity are negative prognostic factors in patients with breast cancer (BC). We found that sensitivity to tamoxifen was reduced by 2-fold by 25 mM glucose (High Glucose; HG) compared to 5.5 mM glucose (Low Glucose; LG) in MCF7 BC cells. Shifting from HG to LG ameliorated MCF7 cell responsiveness to tamoxifen. RNA-Sequencing of MCF7 BC cells revealed that cell cycle-related genes were mainly affected by glucose. Connective Tissue Growth Factor (CTGF) was identified as a glucose-induced modulator of cell sensitivity to tamoxifen. Co-culturing MCF7 cells with human adipocytes exposed to HG, enhanced CTGF mRNA levels and reduced tamoxifen responsiveness of BC cells. Inhibition of adipocyte-released IL8 reverted these effects. Interestingly, CTGF immuno-detection in bioptic specimens from women with estrogen receptor positive (ER + ) BC correlated with hormone therapy resistance, distant metastases, reduced overall and disease-free survival. Thus, glucose affects tamoxifen responsiveness directly modulating CTGF in BC cells, and indirectly promoting IL8 release by adipocytes.

  11. Modulation of the electroluminescence emission from ZnO/Si NCs/p-Si light-emitting devices via pulsed excitation

    Science.gov (United States)

    López-Vidrier, J.; Gutsch, S.; Blázquez, O.; Hiller, D.; Laube, J.; Kaur, R.; Hernández, S.; Garrido, B.; Zacharias, M.

    2017-05-01

    In this work, the electroluminescence (EL) emission of zinc oxide (ZnO)/Si nanocrystals (NCs)-based light-emitting devices was studied under pulsed electrical excitation. Both Si NCs and deep-level ZnO defects were found to contribute to the observed EL. Symmetric square voltage pulses (50-μs period) were found to notably enhance EL emission by about one order of magnitude. In addition, the control of the pulse parameters (accumulation and inversion times) was found to modify the emission lineshape, long inversion times (i.e., short accumulation times) suppressing ZnO defects contribution. The EL results were discussed in terms of the recombination dynamics taking place within the ZnO/Si NCs heterostructure, suggesting the excitation mechanism of the luminescent centers via a combination of electron impact, bipolar injection, and sequential carrier injection within their respective conduction regimes.

  12. Cell Size and Growth Rate Are Modulated by TORC2-Dependent Signals.

    Science.gov (United States)

    Lucena, Rafael; Alcaide-Gavilán, Maria; Schubert, Katherine; He, Maybo; Domnauer, Matthew G; Marquer, Catherine; Klose, Christian; Surma, Michal A; Kellogg, Douglas R

    2018-01-22

    The size of all cells, from bacteria to vertebrates, is proportional to the growth rate set by nutrient availability, but the underlying mechanisms are unknown. Here, we show that nutrients modulate cell size and growth rate via the TORC2 signaling network in budding yeast. An important function of the TORC2 network is to modulate synthesis of ceramide lipids, which play roles in signaling. TORC2-dependent control of ceramide signaling strongly influences both cell size and growth rate. Thus, cells that cannot make ceramides fail to modulate their growth rate or size in response to changes in nutrients. PP2A associated with the Rts1 regulatory subunit (PP2A Rts1 ) is embedded in a feedback loop that controls TORC2 signaling and helps set the level of TORC2 signaling to match nutrient availability. Together, the data suggest a model in which growth rate and cell size are mechanistically linked by ceramide-dependent signals arising from the TORC2 network. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Alcohol and Cardiovascular Disease—Modulation of Vascular Cell Function

    Directory of Open Access Journals (Sweden)

    Paul A. Cahill

    2012-04-01

    Full Text Available Alcohol is a commonly used drug worldwide. Epidemiological studies have identified alcohol consumption as a factor that may either positively or negatively influence many diseases including cardiovascular disease, certain cancers and dementia. Often there seems to be a differential effect of various drinking patterns, with frequent moderate consumption of alcohol being salutary and binge drinking or chronic abuse being deleterious to one’s health. A better understanding of the cellular and molecular mechanisms mediating the many effects of alcohol consumption is beginning to emerge, as well as a clearer picture as to whether these effects are due to the direct actions of alcohol itself, or caused in part by its metabolites, e.g., acetaldehyde, or by incidental components present in the alcoholic beverage (e.g., polyphenols in red wine. This review will discuss evidence to date as to how alcohol (ethanol might affect atherosclerosis that underlies cardiovascular and cerebrovascular disease, and the putative mechanisms involved, focusing on vascular endothelial and smooth muscle cell effects.

  14. Thin Film CIGS Solar Cells, Photovoltaic Modules, and the Problems of Modeling

    Directory of Open Access Journals (Sweden)

    Antonino Parisi

    2013-01-01

    Full Text Available Starting from the results regarding a nonvacuum technique to fabricate CIGS thin films for solar cells by means of single-step electrodeposition, we focus on the methodological problems of modeling at cell structure and photovoltaic module levels. As a matter of fact, electrodeposition is known as a practical alternative to costly vacuum-based technologies for semiconductor processing in the photovoltaic device sector, but it can lead to quite different structural and electrical properties. For this reason, a greater effort is required to ensure that the perspectives of the electrical engineer and the material scientist are given an opportunity for a closer comparison and a common language. Derived parameters from ongoing experiments have been used for simulation with the different approaches, in order to develop a set of tools which can be used to put together modeling both at single cell structure and complete module levels.

  15. Human Intestinal Cells Modulate Conjugational Transfer of Multidrug Resistance Plasmids between Clinical Escherichia coli Isolates

    DEFF Research Database (Denmark)

    Machado, Ana Manuel; Sommer, Morten

    2014-01-01

    Bacterial conjugation in the human gut microbiota is believed to play a major role in the dissemination of antibiotic resistance genes and virulence plasmids. However, the modulation of bacterial conjugation by the human host remains poorly understood and there is a need for controlled systems...... to study this process. We established an in vitro co-culture system to study the interaction between human intestinal cells and bacteria. We show that the conjugation efficiency of a plasmid encoding an extended spectrum beta-lactamase is reduced when clinical isolates of Escherichia coli are co...... of the intestinal cells exposed to bacteria leading to a two-fold reduction in conjugation efficiency. These results show that human gut epithelial cells can modulate bacterial conjugation and may have relevance to gene exchange in the gut....

  16. Whole-body water flow stimulation to the lower limbs modulates excitability of primary motor cortical regions innervating the hands: a transcranial magnetic stimulation study.

    Directory of Open Access Journals (Sweden)

    Daisuke Sato

    Full Text Available Whole-body water immersion (WI has been reported to change sensorimotor integration. However, primary motor cortical excitability is not affected by low-intensity afferent input. Here we explored the effects of whole-body WI and water flow stimulation (WF on corticospinal excitability and intracortical circuits. Eight healthy subjects participated in this study. We measured the amplitude of motor-evoked potentials (MEPs produced by single transcranial magnetic stimulation (TMS pulses and examined conditioned MEP amplitudes by paired-pulse TMS. We evaluated short-interval intracortical inhibition (SICI and intracortical facilitation (ICF using the paired-TMS technique before and after 15-min intervention periods. Two interventions used were whole-body WI with water flow to the lower limbs (whole-body WF and whole-body WI without water flow to the lower limbs (whole-body WI. The experimental sequence included a baseline TMS assessment (T0, intervention for 15 min, a second TMS assessment immediately after intervention (T1, a 10 min resting period, a third TMS assessment (T2, a 10 min resting period, a fourth TMS assessment (T3, a 10 min resting period, and the final TMS assessment (T4. SICI and ICF were evaluated using a conditioning stimulus of 90% active motor threshold and a test stimulus adjusted to produce MEPs of approximately 1-1.2 mV, and were tested at intrastimulus intervals of 3 and 10 ms, respectively. Whole-body WF significantly increased MEP amplitude by single-pulse TMS and led to a decrease in SICI in the contralateral motor cortex at T1, T2 and T3. Whole-body WF also induced increased corticospinal excitability and decreased SICI. In contrast, whole-body WI did not change corticospinal excitability or intracortical circuits.

  17. Whole-body water flow stimulation to the lower limbs modulates excitability of primary motor cortical regions innervating the hands: a transcranial magnetic stimulation study.

    Science.gov (United States)

    Sato, Daisuke; Yamashiro, Koya; Onishi, Hideaki; Baba, Yasuhiro; Nakazawa, Sho; Shimoyama, Yoshimitsu; Maruyama, Atsuo

    2014-01-01

    Whole-body water immersion (WI) has been reported to change sensorimotor integration. However, primary motor cortical excitability is not affected by low-intensity afferent input. Here we explored the effects of whole-body WI and water flow stimulation (WF) on corticospinal excitability and intracortical circuits. Eight healthy subjects participated in this study. We measured the amplitude of motor-evoked potentials (MEPs) produced by single transcranial magnetic stimulation (TMS) pulses and examined conditioned MEP amplitudes by paired-pulse TMS. We evaluated short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) using the paired-TMS technique before and after 15-min intervention periods. Two interventions used were whole-body WI with water flow to the lower limbs (whole-body WF) and whole-body WI without water flow to the lower limbs (whole-body WI). The experimental sequence included a baseline TMS assessment (T0), intervention for 15 min, a second TMS assessment immediately after intervention (T1), a 10 min resting period, a third TMS assessment (T2), a 10 min resting period, a fourth TMS assessment (T3), a 10 min resting period, and the final TMS assessment (T4). SICI and ICF were evaluated using a conditioning stimulus of 90% active motor threshold and a test stimulus adjusted to produce MEPs of approximately 1-1.2 mV, and were tested at intrastimulus intervals of 3 and 10 ms, respectively. Whole-body WF significantly increased MEP amplitude by single-pulse TMS and led to a decrease in SICI in the contralateral motor cortex at T1, T2 and T3. Whole-body WF also induced increased corticospinal excitability and decreased SICI. In contrast, whole-body WI did not change corticospinal excitability or intracortical circuits.

  18. L-Glutamine in vitro Modulates some Immunomodulatory Properties of Bone Marrow Mesenchymal Stem Cells.

    Science.gov (United States)

    Dos Santos, Guilherme Galvão; Hastreiter, Araceli Aparecida; Sartori, Talita; Borelli, Primavera; Fock, Ricardo Ambrósio

    2017-08-01

    Glutamine (GLUT) is a nonessential amino acid that can become conditionally essential under stress conditions, being able to act in the modulation of the immune responses. Mesenchymal stem cells (MSCs) are known to their capability in the modulation of immune responses through cell-cell contact and by the secretion of soluble factors. Considering that GLUT is an immunonutrient and little is known about the influence of GLUT on the capability of MSCs to modulate immune cells, this work aims to investigate how variations in GLUT concentrations in vitro could affect some immunomodulatory properties of MSCs. In order to evaluate the effects of GLUT on MSCs immunomodulatory properties, cell proliferation rates, the expression of NFκB and STAT-3, and the production of IL-1β, IL-6, IL-10, TGF-β and TNF-α by MSCs were assessed. Based on our findings, GLUT at high doses (10 mM) augmented the proliferation of MSCs and modulated immune responses by decreasing levels of pro-inflammatory cytokines, such as IL-1β and IL-6, and by increasing levels of anti-inflammatory cytokines IL-10 and TGF-β. In addition, MSCs cultured in higher GLUT concentrations (10 mM) expressed lower levels of NF-κB and higher levels of STAT-3. Furthermore, conditioned media from MSCs cultured at higher GLUT concentrations (10 mM) reduced lymphocyte and macrophage proliferation, increased IL-10 production by both cells types, and decreased IFN-γ production by lymphocytes. Overall, this study showed that 10 mM of GLUT is able to modify immunomodulatory properties of MSCs.

  19. Fiscal 1999 leading research report. Research on 3-D cell tissue module technology; 1999 nendo sanjigen saibo soshiki module kogaku chosa kenkyu hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    For forming cell tissues alternative to bio-tissues, this research targets the technology for forming bio-tissue modules by cultivating 3-D cell tissues from various kinds of cells. In fiscal 1999, research was made on various issues of element technologies necessary for forming module structure of bio-tissues, and study was also made on the application of 3-D cell tissue module engineering to industrial fields. Survey was made on element technologies and solutions supporting such engineering, and in addition, on progressive conditions of cell cultivation techniques, and concrete techniques for expressing cell functions. Research was made on a cell behavior under physicochemical stimulus environment to study the optimum environment for cell multiplication and function expression. Further research was made on state analysis of cells, in particular, fast precise measurement techniques of activation or malignant of cells and secretion of toxic substances by physical/optical analytical evaluation techniques such as photo-CT and spectroscopic analysis, and biochemical analysis techniques using bio-sensors. Study was also made on successful development and application cases of practical bio-artificial organs in western countries. (NEDO)

  20. Thermal investigation of lithium-ion battery module with different cell arrangement structures and forced air-cooling strategies

    International Nuclear Information System (INIS)

    Wang, Tao; Tseng, K.J.; Zhao, Jiyun; Wei, Zhongbao

    2014-01-01

    Highlights: • Three-dimensional CFD model with forced air cooling are developed for battery modules. • Impact of different air cooling strategies on module thermal characteristics are investigated. • Impact of different model structures on module thermal responses are investigated. • Effect of inter-cell spacing on cell thermal characteristics are also studied. • The optimal battery module structure and air cooling strategy is recommended. - Abstract: Thermal management needs to be carefully considered in the lithium-ion battery module design to guarantee the temperature of batteries in operation within a narrow optimal range. This article firstly explores the thermal performance of battery module under different cell arrangement structures, which includes: 1 × 24, 3 × 8 and 5 × 5 arrays rectangular arrangement, 19 cells hexagonal arrangement and 28 cells circular arrangement. In addition, air-cooling strategies are also investigated by installing the fans in the different locations of the battery module to improve the temperature uniformity. Factors that influence the cooling capability of forced air cooling are discussed based on the simulations. The three-dimensional computational fluid dynamics (CFD) method and lumped model of single cell have been applied in the simulation. The temperature distributions of batteries are quantitatively described based on different module patterns, fan locations as well as inter-cell distance, and the conclusions are arrived as follows: when the fan locates on top of the module, the best cooling performance is achieved; the most desired structure with forced air cooling is cubic arrangement concerning the cooling effect and cost, while hexagonal structure is optimal when focus on the space utilization of battery module. Besides, the optimized inter-cell distance in battery module structure has been recommended

  1. The peripheral NK cell repertoire after kidney transplantation is modulated by different immunosuppressive drugs

    Directory of Open Access Journals (Sweden)

    Christine eNeudoerfl

    2013-02-01

    Full Text Available In the context of kidney transplantation, little is known about the involvement of NK cells in the immune reaction leading to either rejection or immunological tolerance under immunosuppression. Therefore, the peripheral NK cell repertoire of patients after kidney transplantation was investigated in order to identify NK cell subsets that may be associated with the individual immune status at the time of their protocol biopsies for histopathological evaluation of the graft. Alterations in the peripheral NK cell repertoire could be correlated to the type of immunosuppression, i.e. calcineurin-inhibitors like CyclosporinA vs. Tacrolimus with or without addition of mTOR inhibitors. Here, we could demonstrate that the NK cell repertoire in peripheral blood of kidney transplant patients differs significantly from healthy individuals. The presence of donor-specific antibodies was associated with reduced numbers of CD56dim NK cells. Moreover, in patients, down-modulation of CD16 and CD6 on CD56dim NK cells was observed with significant differences between CyclosporinA- and Tac-treated patients. Tac-treatment was associated with decreased CD69, HLA-DR and increased CD94/NKG2A expression in CD56dim NK cells indicating that the quality of the immunosuppressive treatment impinges on the peripheral NK cell repertoire. In vitro studies with PBMC of healthy donors showed that this modulation of CD16, CD6, CD69, and HLA-DR could also be induced experimentally. The presence of calcineurin or mTOR inhibitors had also functional consequences regarding degranulation and IFN--production against K562 target cells, respectively. In summary, we postulate that the NK cell composition in peripheral blood of kidney transplanted patients represents an important hallmark of the efficacy of immunosuppression and may be even informative for the immune status after transplantation in terms of rejection vs. drug-induced allograft tolerance. Thus,NK cells can serve as sensors

  2. Integrated modulation of phorbol ester-induced Raf activation in EL4 lymphoma cells.

    Science.gov (United States)

    Han, Shujie; Meier, Kathryn E

    2009-05-01

    The EL4 murine lymphoma cell line exists in variant phenotypes that differ with respect to responses to the tumor promoter phorbol 12-myristate 13-acetate (PMA1). Previous work showed that "PMA-sensitive" cells, characterized by a high magnitude of PMA-induced Erk activation, express RasGRP, a phorbol ester receptor that directly activates Ras. In "PMA-resistant" and "intermediate" EL4 cell lines, PMA induces Erk activation to lesser extents, but with a greater response in intermediate cells. In the current study, these cell lines were used to examine mechanisms of Raf-1 modulation. Phospho-specific antibodies were utilized to define patterns and kinetics of Raf-1 phosphorylation on several sites. Further studies showed that Akt is constitutively activated to a greater extent in PMA-resistant than in PMA-sensitive cells, and also to a greater extent in resistant than intermediate cells. Akt negatively regulates Raf-1 activation (Ser259), partially explaining the difference between resistant and intermediate cells. Erk activation exerts negative feedback on Raf-1 (Ser289/296/301), thus resulting in earlier termination of the signal in cells with a higher level of Erk activation. RKIP, a Raf inhibitory protein, is expressed at higher levels in resistant cells than in sensitive or intermediate cells. Knockdown of RKIP increases Erk activation and also negative feedback. In conclusion, this study delineates Raf-1 phosphorylation events occurring in response to PMA in cell lines with different extents of Erk activation. Variations in the levels of expression and activation of multiple signaling proteins work in an integrated fashion to modulate the extent and duration of Erk activation.

  3. Structural defects and recombination behavior of excited carriers in Cu(In,Ga)Se{sub 2} solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J.; Du, H. W.; Li, Y.; Gao, M.; Wan, Y. Z.; Xu, F. [SHU-SolarE R& D Lab, Department of Physics, Shanghai University, Shanghai, 200444 (China); Ma, Z. Q., E-mail: zqma@shu.edu.cn [SHU-SolarE R& D Lab, Department of Physics, Shanghai University, Shanghai, 200444 (China); Instrumental Analysis & Research Center, Shanghai University, Shanghai, 200444 (China)

    2016-08-15

    The carriers’ behavior in neutral region (NTR) and space charged region (SCR) of Cu(In,Ga)Se{sub 2} thin film based solar cells has been investigated by temperature dependent photoluminescence (PL-T), electroluminescence (EL-T) and current-voltage (IV-T) from 10 to 300 K. PL-T spectra show that three kinds of defects, namely V{sub Se}, In{sub Cu} and (In{sub Cu}+V{sub Cu}), are localized within the band gap of NTR and SCR of CIGS layer, corresponding to the energy levels of E{sub C}-0.08, E{sub C}-0.20 and E{sub C}-0.25 eV, respectively. The In{sub Cu} and (In{sub Cu}+V{sub Cu}) deep level defects are non-radiative recombination centers at room temperature. The IV-T and EL-T analysis reveals that the injection modes of electrons from ZnO conduction band into Cu(In,Ga)Se{sub 2} layer are tunneling, thermally-excited tunneling and thermionic emission under 10-40, 60-160, and 180-300 K, respectively. At 10-160 K, the electrons tunnel into (In{sub Cu}+V{sub Cu}) and V{sub se} defect levels in band gap of SCR and the drifting is involved in the emission bands at 0.96 and 1.07 eV, which is the direct evidence for a tunneling assisted recombination. At 180-300 K, the electrons are directly injected into the Cu(In,Ga)Se{sub 2} conduction band, and the emission of 1.13 eV are ascribed to the transitions from the conduction band to the valence band.

  4. Magnetic excitations in amorphous ferromagnets

    International Nuclear Information System (INIS)

    Continentino, M.A.

    The propagation of magnetic excitations in amorphous ferromagnets is studied from the point of view of the theory of random frequency modulation. It is shown that the spin waves in the hydrodynamic limit are well described by perturbation theory while the roton-like magnetic excitations with wavevector about the peak in the structure factor are not. A criterion of validity of perturbation theory is found which is identical to a narrowing condition in magnetic resonance. (author) [pt

  5. Cross-reactive microbial peptides can modulate HIV-specific CD8+ T cell responses.

    Directory of Open Access Journals (Sweden)

    Christopher W Pohlmeyer

    Full Text Available Heterologous immunity is an important aspect of the adaptive immune response. We hypothesized that this process could modulate the HIV-1-specific CD8+ T cell response, which has been shown to play an important role in HIV-1 immunity and control. We found that stimulation of peripheral blood mononuclear cells (PBMCs from HIV-1-positive subjects with microbial peptides that were cross-reactive with immunodominant HIV-1 epitopes resulted in dramatic expansion of HIV-1-specific CD8+ T cells. Interestingly, the TCR repertoire of HIV-1-specific CD8+ T cells generated by ex vivo stimulation of PBMCs using HIV-1 peptide was different from that of cells stimulated with cross-reactive microbial peptides in some HIV-1-positive subjects. Despite these differences, CD8+ T cells stimulated with either HIV-1 or cross-reactive peptides effectively suppressed HIV-1 replication in autologous CD4+ T cells. These data suggest that exposure to cross-reactive microbial antigens can modulate HIV-1-specific immunity.

  6. Dickkopf-3, a tissue-derived modulator of local T cell responses

    Directory of Open Access Journals (Sweden)

    Michael eMeister

    2015-02-01

    Full Text Available The adaptive immune system protects organisms from harmful environmental insults. In parallel, regulatory mechanisms control immune responses in order to assure preservation of organ integrity. Yet, molecules involved in the control of T cell responses in peripheral tissues are poorly characterized. Here, we investigated the function of Dickkopf-3 in the modulation of local T cell reactivity. Dkk3 is a secreted, mainly tissue derived protein with highest expression in organs considered as immune privileged such as the eye, embryo, placenta and brain. While T cell development and activation status in naïve Dkk3 deficient mice was comparable to littermate controls, we found that Dkk3 contributes to the immunosuppressive microenvironment that protects transplanted, class-I mismatched embryoid bodies from T cell mediated rejection. Moreover, genetic deletion or antibody mediated neutralization of Dkk3 led to an exacerbated experimental autoimmune encephalomyelitis (EAE. This phenotype was accompanied by a change of T cell polarization displayed by an increase of IFNγ producing T cells within in the CNS. In the wild type situation, Dkk3 expression in the brain was up-regulated during the course of EAE in an IFNγ dependent manner. In turn, Dkk3 decreased IFNγ activity and served as part of a negative feedback mechanism. Thus, our findings suggest that Dkk3 functions as a tissue-derived modulator of local CD4+ and CD8+ T cell responses.

  7. TRAF2 regulates peripheral CD8(+) T-cell and NKT-cell homeostasis by modulating sensitivity to IL-15.

    Science.gov (United States)

    Villanueva, Jeanette E; Malle, Elisabeth K; Gardam, Sandra; Silveira, Pablo A; Zammit, Nathan W; Walters, Stacey N; Brink, Robert; Grey, Shane T

    2015-06-01

    In this study, a critical and novel role for TNF receptor (TNFR) associated factor 2 (TRAF2) is elucidated for peripheral CD8(+) T-cell and NKT-cell homeostasis. Mice deficient in TRAF2 only in their T cells (TRAF2TKO) show ∼40% reduction in effector memory and ∼50% reduction in naïve CD8(+) T-cell subsets. IL-15-dependent populations were reduced further, as TRAF2TKO mice displayed a marked ∼70% reduction in central memory CD8(+) CD44(hi) CD122(+) T cells and ∼80% decrease in NKT cells. TRAF2TKO CD8(+) CD44(hi) T cells exhibited impaired dose-dependent proliferation to exogenous IL-15. In contrast, TRAF2TKO CD8(+) T cells proliferated normally to anti-CD3 and TRAF2TKO CD8(+) CD44(hi) T cells exhibited normal proliferation to exogenous IL-2. TRAF2TKO CD8(+) T cells expressed normal levels of IL-15-associated receptors and possessed functional IL-15-mediated STAT5 phosphorylation, however TRAF2 deletion caused increased AKT activation. Loss of CD8(+) CD44(hi) CD122(+) and NKT cells was mechanistically linked to an inability to respond to IL-15. The reduced CD8(+) CD44(hi) CD122(+) T-cell and NKT-cell populations in TRAF2TKO mice were rescued in the presence of high dose IL-15 by IL-15/IL-15Rα complex administration. These studies demonstrate a critical role for TRAF2 in the maintenance of peripheral CD8(+) CD44(hi) CD122(+) T-cell and NKT-cell homeostasis by modulating sensitivity to T-cell intrinsic growth factors such as IL-15. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Modulation of dendritic cell and T cell cross-talk during aging: The potential role of checkpoint inhibitory molecules.

    Science.gov (United States)

    Gardner, Joanne K; Mamotte, Cyril D S; Jackaman, Connie; Nelson, Delia J

    2017-09-01

    Dendritic cells (DCs) undergo continuous changes throughout life, and there is evidence that elderly DCs have a reduced capacity to stimulate T cells, which may contribute to impaired anti-tumour immune responses in elderly people with cancer. Changes in checkpoint inhibitory molecules/pathways during aging may be one mechanism that impairs the ability of elderly DCs to activate T cells. However, little is currently known regarding the combined effects of aging and cancer on DC and T cell inhibitory molecules/pathways. In this review, we discuss our current understanding of the influence of aging and cancer on key DC and T cell inhibitory molecules/pathways, the potential underlying cellular and molecular mechanisms contributing to their modulation, and the possibility of therapeutically targeting inhibitory molecules in elderly cancer patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Human DAZL, DAZ and BOULE genes modulate primordial germ cell and haploid gamete formation

    Science.gov (United States)

    Kee, Kehkooi; Angeles, Vanessa T; Flores, Martha; Nguyen, Ha Nam; Pera, Renee A Reijo

    2009-01-01

    The leading cause of infertility in men and women is quantitative and qualitative defects in human germ cell (oocyte and sperm) development. Yet, it has not been possible to examine the unique developmental genetics of human germ cell formation and differentiation due to inaccessibility of germ cells during fetal development. Although several studies have shown that germ cells can be differentiated from mouse and human embryonic stem cells, human germ cells differentiated in these studies generally did not develop beyond the earliest stages1-8. Here we used a germ cell reporter to quantitate and isolate primordial germ cells derived from both male and female hESCs. Then, by silencing and overexpressing genes that encode germ cell-specific cytoplasmic RNA-binding proteins (not transcription factors), we modulated human germ cell formation and developmental progression. We observed that human DAZL (Deleted in AZoospermia-Like) functions in primordial germ cell formation, whereas closely-related genes, DAZ and BOULE, promote later stages of meiosis and development of haploid gametes. These results are significant to the generation of gametes for future basic science and potential clinical applications. PMID:19865085

  10. IL-21 Modulates Activation of NKT Cells in Patients with Stage IV Malignant Melanoma.

    Science.gov (United States)

    Coquet, Jonathan M; Skak, Kresten; Davis, Ian D; Smyth, Mark J; Godfrey, Dale I

    2013-10-01

    Interleukin-21 (IL-21) is a common γ-chain cytokine produced by T helper and natural killer T (NKT) cells. It has been shown to regulate the response of various lymphocyte subsets including NK, NKT, T and B cells. Owing to its potent anti-tumor function in preclinical studies and its ability to induce cytotoxicity and interferon-γ (IFN-γ) production in NK and CD8 T cells, recombinant IL-21 (rIL-21) was fast-tracked into early-phase clinical trials of patients with various malignancies. In a phase 2a trial of patients with metastatic melanoma, we analyzed the frequency and function of NKT cells in patients receiving rIL-21. NKT cells were present at a low frequency, but their levels were relatively stable in patients administered rIL-21. Unlike our observations in NK and CD8 T cells, rIL-21 appeared to reduce IFN-γ and TNF production by NKT cells, whereas it enhanced IL-4 production. It also modulated the expression of cell surface markers, specifically on CD4(-) NKT cells. In addition, an increase in CD3(+)CD56(+) NKT-like cells was observed over the course of rIL-21 administration. These results highlight that IL-21 is a potent regulator of NKT cell function in vivo.

  11. PHYSICAL CONTACT BETWEEN HUMAN VASCULAR ENDOTHELIAL AND SMOOTH MUSCLE CELLS MODULATES CYTOSOLIC AND NUCLEAR CALCIUM HOMEOSTASIS.

    Science.gov (United States)

    Hassan, Ghada S; Jacques, Danielle; D'Orleans-Juste, Pedro; Magder, Sheldon; Bkaily, Ghassan

    2018-05-14

    The interaction between vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs) plays an important role in the modulation of vascular tone. There is however no information on whether direct physical communication regulates the intracellular calcium levels of human VECs (hVECs) and/or hVSMCs . Thus, the objective of the study is to verify whether co-culture of hVECs and hVSMCs modulates cytosolic ([Ca2+]c) and nuclear calcium ([Ca2+]n) levels via physical contact and/or factors released by both cell types. Quantitative 3D confocal microscopy for [Ca2+]c and [Ca2+]n measurement was performed in cultured hVECs or hVSMCs or in co-culture of hVECs-hVSMCs. Our results show that: 1) physical contact between hVECs-hVECs or hVSMCs-hVSMCs does not affect [Ca2+]c and [Ca2+]n in these two cell types; 2) physical contact between hVECs and hVSMCs induces a significant increase only of [Ca2+]n of hVECs without affecting the level of [Ca2+]c and [Ca2+]n of hVSMCs; and 3) preconditioned culture medium of hVECs or hVSMCs does not affect [Ca2+]c and [Ca2+]n of both types of cells. We concluded that physical contact between hVECs and hVSMCs only modulates [Ca2+]n in hVECs. The increase of [Ca2+]n in hVECs may modulate nuclear functions that are calcium dependent.

  12. Membrane depolarization increases ryanodine sensitivity to Ca2+ release to the cytosol in L6 skeletal muscle cells: Implications for excitation-contraction coupling.

    Science.gov (United States)

    Pitake, Saumitra; Ochs, Raymond S

    2016-04-01

    The dihydropyridine receptor in the plasma membrane and the ryanodine receptor in the sarcoplasmic reticulum are known to physically interact in the process of excitation-contraction coupling. However, the mechanism for subsequent Ca(2+) release through the ryanodine receptor is unknown. Our lab has previously presented evidence that the dihydropyridine receptor and ryanodine receptor combine as a channel for the entry of Ca(2+) under resting conditions, known as store operated calcium entry. Here, we provide evidence that depolarization during excitation-contraction coupling causes the dihydropyridine receptor to disengage from the ryanodine receptor. The newly freed ryanodine receptor can then transport Ca(2+) from the sarcoplasmic reticulum to the cytosol. Experimentally, this should more greatly expose the ryanodine receptor to exogenous ryanodine. To examine this hypothesis, we titrated L6 skeletal muscle cells with ryanodine in resting and excited (depolarized) states. When L6 muscle cells were depolarized with high potassium or exposed to the dihydropyridine receptor agonist BAYK-8644, known to induce dihydropyridine receptor movement within the membrane, ryanodine sensitivity was enhanced. However, ryanodine sensitivity was unaffected when Ca(2+) was elevated without depolarization by the ryanodine receptor agonist chloromethylcresol, or by increasing Ca(2+) concentration in the media. Ca(2+) entry currents (from the extracellular space) during excitation were strongly inhibited by ryanodine, but Ca(2+) entry currents in the resting state were not. We conclude that excitation releases the ryanodine receptor from occlusion by the dihydropyridine receptor, enabling Ca(2+) release from the ryanodine receptor to the cytosol. © 2015 by the Society for Experimental Biology and Medicine.

  13. A visible-light-excited europium(III) complex-based luminescent probe for visualizing copper ions and hydrogen sulfide in living cells

    Science.gov (United States)

    Wang, Yiren; Wang, Huan; Yang, Mei; Yuan, Jingli; Wu, Jing

    2018-01-01

    Development of visible-light-excited lanthanide (III) complex-based luminescent probes is highly appealing due to their superiority of less damage to the living biosystems over the conventional UV-light-excited ones. In this work, a visible-light-excited europium (III) complex-based luminescent probe, BPED-BHHCT-Eu3+-BPT, has been designed and synthesized by conjugating the Cu2+-binding N,N-bis(2-pyridylmethyl)ethanediamine (BPED) to a tetradentate β-diketone ligand 4,4‧-bis(1″,1″,1″,2″,2″,3″,3″-heptafluoro-4″,6″-hexanedione-6″-yl)chlorosulfo-o-terphenyl (BHHCT) and coordinating with a coligand 2-(N,N-diethylanilin-4-yl)-4,6-bis(pyrazol-1-yl)-1,3,5-triazine) (BPT) for the time-gated luminescence detection of Cu2+ ions and hydrogen sulfide (H2S) in living cells. BPED-BHHCT-Eu3+-BPT exhibited a sharp excitation peak at 407 nm and a wide excitation window extending to beyond 460 nm. Upon its reaction with Cu2+ ions, the luminescence of BPED-BHHCT-Eu3+-BPT was efficiently quenched, which could be reversibly restored by the addition of H2S due to the strong affinity between Cu2+ ions and H2S. The "on-off-on" type luminescence behavior of BPED-BHHCT-Eu3+-BPT towards Cu2+ ions and H2S enabled the sensing of the two species with high sensitivity and selectivity. The performances of BPED-BHHCT-Eu3+-BPT for visualizing intracellular Cu2+ ions and H2S were investigated, and the results have demonstrated the practical applicability of the probe for molecular imaging of cells.

  14. Design, fabrication and testing of a 5-Hz acoustic exciter system

    Science.gov (United States)

    Lundy, D. H.; Robinson, G. D.

    1973-01-01

    A 5-Hz acoustic excitation system was designed, fabricated and checked out for use in the modulation of a stagnant gas volume contained in an absorption cell. A detailed system description of the test equipment, both mechanical and electronic, and an operating procedure are included. Conclusions are also presented.

  15. Ghrelin modulates testicular germ cells apoptosis and proliferation in adult normal rats

    International Nuclear Information System (INIS)

    Kheradmand, Arash; Dezfoulian, Omid; Alirezaei, Masoud; Rasoulian, Bahram

    2012-01-01

    Highlights: ► Spermatogenesis is closely associated with the balance between germ cells proliferation and apoptosis. ► Numerous studies have documented the direct action of ghrelin in the modulation of apoptosis in different cell types. ► Ghrelin may be considered as a modulator of spermatogenesis in normal adult rats. ► Ghrelin may be potentially implicated for abnormal spermatogenesis in some testicular germ cell tumors. -- Abstract: Under normal condition in the most mammals, spermatogenesis is closely associated with the balance between germ cells proliferation and apoptosis. The present study was designed to determine the effects of ghrelin treatment on in vivo quality and quantity expression of apoptosis and proliferation specific indices in rat testicular germ cells. Twenty eight adult normal rats were subdivided into equal control and treatment groups. Treatment group received 3 nmol of ghrelin as subcutaneous injection for 30 consecutive days or vehicle to the control animals. The rats from each group (n = 7) were killed on days 10 and 30 and their testes were taken for immunocytochemical evaluation and caspase-3 assay. Immunohistochemical analysis indicated that the accumulations of Bax and PCNA peptides are generally more prominent in spermatocytes and spermatogonia of both groups. Likewise, the mean percentage of immunoreactive spermatocytes against Bax increased (P 0.05). Upstream of Bax substance parallel to down-regulation of PCNA demonstrate that ghrelin may prevent massive accumulation of germ cells during normal spermatogenesis. These observations also indicate that ghrelin may be considered as a modulator of spermatogenesis in normal adult rats and could be potentially implicated for abnormal spermatogenesis in some testicular germ cell tumors.

  16. Cell intrinsic modulation of Wnt signaling controls neuroblast migration in C. elegans.

    Science.gov (United States)

    Mentink, Remco A; Middelkoop, Teije C; Rella, Lorenzo; Ji, Ni; Tang, Chung Yin; Betist, Marco C; van Oudenaarden, Alexander; Korswagen, Hendrik C

    2014-10-27

    Members of the Wnt family of secreted signaling proteins are key regulators of cell migration and axon guidance. In the nematode C. elegans, the migration of the QR neuroblast descendants requires multiple Wnt ligands and receptors. We found that the migration of the QR descendants is divided into three sequential phases that are each mediated by a distinct Wnt signaling mechanism. Importantly, the transition from the first to the second phase, which is the main determinant of the final position of the QR descendants along the anteroposterior body axis, is mediated through a cell-autonomous process in which the time-dependent expression of a Wnt receptor turns on the canonical Wnt/β-catenin signaling response that is required to terminate long-range anterior migration. Our results show that, in addition to direct guidance of cell migration by Wnt morphogenic gradients, cell migration can also be controlled indirectly through cell-intrinsic modulation of Wnt signaling responses.

  17. Modulation of Immune Responses by Exosomes Derived from Antigen-Presenting Cells

    Directory of Open Access Journals (Sweden)

    Botros B. Shenoda

    2016-01-01

    Full Text Available Exosome-mediated signaling is important in mediating the inflammatory response. To exert their biological or pathophysiological functions in the recipient cells, exosomes deliver a diverse array of biomacromolecules including long and short coding and non-coding RNAs, proteins, and lipids. Exosomes secreted by antigen-presenting cells can confer therapeutic benefits by attenuating or stimulating the immune response. Exosomes play a crucial role in carrying and presenting functional major histocompatibility peptide complexes to modulate antigen-specific T cell responses. Exosomes from Dendritic Cells (DCs can activate T and B cells and have been explored for their immunostimulatory properties in cancer therapy. The immunosuppressive properties of exosomes derived from macrophages and DCs can reduce inflammation in animal models for several inflammatory disorders. This review focuses on the protective role of exosomes in attenuating inflammation or augmenting immune response, emphasizing studies on exosomes derived from DCs and macrophages.

  18. Modulating Estrogen Receptor-related Receptor-α Activity Inhibits Cell Proliferation*

    Science.gov (United States)

    Bianco, Stéphanie; Lanvin, Olivia; Tribollet, Violaine; Macari, Claire; North, Sophie; Vanacker, Jean-Marc

    2009-01-01

    High expression of the estrogen receptor-related receptor (ERR)-α in human tumors is correlated to a poor prognosis, suggesting an involvement of the receptor in cell proliferation. In this study, we show that a synthetic compound (XCT790) that modulates the activity of ERRα reduces the proliferation of various cell lines and blocks the G1/S transition of the cell cycle in an ERRα-dependent manner. XCT790 induces, in a p53-independent manner, the expression of the cell cycle inhibitor p21waf/cip1 at the protein, mRNA, and promoter level, leading to an accumulation of hypophosphorylated Rb. Finally, XCT790 reduces cell tumorigenicity in Nude mice. PMID:19546226

  19. Dye-sensitized solar cells and solar module using polymer electrolytes: Stability and performance investigations

    Directory of Open Access Journals (Sweden)

    Jilian Nei de Freitas

    2006-01-01

    Full Text Available We present recent results on solid-state dye-sensitized solar cell research using a polymer electrolyte based on a poly(ethylene oxide derivative. The stability and performance of the devices have been improved by a modification in the method of assembly of the cells and by the addition of plasticizers in the electrolyte. After 30 days of solar irradiation (100 mW cm-2 no changes in the cell's efficiency were observed using this new method. The effect of the active area size on cell performance and the first results obtained for the first solar module composed of 4.5 cm2 solid-state solar cells are also presented.

  20. Coxiella burnetii Nine Mile II proteins modulate gene expression of monocytic host cells during infection

    Directory of Open Access Journals (Sweden)

    Shaw Edward I

    2010-09-01

    Full Text Available Abstract Background Coxiella burnetii is an intracellular bacterial pathogen that causes acute and chronic disease in humans. Bacterial replication occurs within enlarged parasitophorous vacuoles (PV of eukaryotic cells, the biogenesis and maintenance of which is dependent on C. burnetii protein synthesis. These observations suggest that C. burnetii actively subverts host cell processes, however little is known about the cellular biology mechanisms manipulated by the pathogen during infection. Here, we examined host cell gene expression changes specifically induced by C. burnetii proteins during infection. Results We have identified 36 host cell genes that are specifically regulated when de novo C. burnetii protein synthesis occurs during infection using comparative microarray analysis. Two parallel sets of infected and uninfected THP-1 cells were grown for 48 h followed by the addition of chloramphenicol (CAM to 10 μg/ml in one set. Total RNA was harvested at 72 hpi from all conditions, and microarrays performed using Phalanx Human OneArray™ slides. A total of 784 (mock treated and 901 (CAM treated THP-1 genes were up or down regulated ≥2 fold in the C. burnetii infected vs. uninfected cell sets, respectively. Comparisons between the complementary data sets (using >0 fold, eliminated the common gene expression changes. A stringent comparison (≥2 fold between the separate microarrays revealed 36 host cell genes modulated by C. burnetii protein synthesis. Ontological analysis of these genes identified the innate immune response, cell death and proliferation, vesicle trafficking and development, lipid homeostasis, and cytoskeletal organization as predominant cellular functions modulated by C. burnetii protein synthesis. Conclusions Collectively, these data indicate that C. burnetii proteins actively regulate the expression of specific host cell genes and pathways. This is in addition to host cell genes that respond to the presence of the

  1. Immune modulation by genetic modification of dendritic cells with lentiviral vectors.

    Science.gov (United States)

    Liechtenstein, Therese; Perez-Janices, Noemi; Bricogne, Christopher; Lanna, Alessio; Dufait, Inès; Goyvaerts, Cleo; Laranga, Roberta; Padella, Antonella; Arce, Frederick; Baratchian, Mehdi; Ramirez, Natalia; Lopez, Natalia; Kochan, Grazyna; Blanco-Luquin, Idoia; Guerrero-Setas, David; Breckpot, Karine; Escors, David

    2013-09-01

    Our work over the past eight years has focused on the use of HIV-1 lentiviral vectors (lentivectors) for the genetic modification of dendritic cells (DCs) to control their functions in immune modulation. DCs are key professional antigen presenting cells which regulate the activity of most effector immune cells, including T, B and NK cells. Their genetic modification provides the means for the development of targeted therapies towards cancer and autoimmune disease. We have been modulating with lentivectors the activity of intracellular signalling pathways and co-stimulation during antigen presentation to T cells, to fine-tune the type and strength of the immune response. In the course of our research, we have found unexpected results such as the surprising immunosuppressive role of anti-viral signalling pathways, and the close link between negative co-stimulation in the immunological synapse and T cell receptor trafficking. Here we review our major findings and put them into context with other published work. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Cervical cancer cell lines expressing NKG2D-ligands are able to down-modulate the NKG2D receptor on NKL cells with functional implications

    Directory of Open Access Journals (Sweden)

    Jimenez-Perez Miriam I

    2012-02-01

    Full Text Available Abstract Background Cervical cancer represents the third most commonly diagnosed cancer and the fourth leading cause of cancer-related deaths in women worldwide. Natural killer (NK cells play an important role in the defense against viruses, intracellular bacteria and tumors. NKG2D, an activating receptor on NK cells, recognizes MHC class I chain-related molecules, such as MICA/B and members of the ULBP/RAET1 family. Tumor-derived soluble NKG2D-ligands have been shown to down-modulate the expression of NKG2D on NK cells. In addition to the down-modulation induced by soluble NKG2D-ligands, it has recently been described that persistent cell-cell contact can also down-modulate NKG2D expression. The goal of this study was to determine whether the NKG2D receptor is down-modulated by cell-cell contact with cervical cancer cells and whether this down-modulation might be associated with changes in NK cell activity. Results We demonstrate that NKG2D expressed on NKL cells is down-modulated by direct cell contact with cervical cancer cell lines HeLa, SiHa, and C33A, but not with non-tumorigenic keratinocytes (HaCaT. Moreover, this down-modulation had functional implications. We found expression of NKG2D-ligands in all cervical cancer cell lines, but the patterns of ligand distribution were different in each cell line. Cervical cancer cell lines co-cultured with NKL cells or fresh NK cells induced a marked diminution of NKG2D expression on NKL cells. Additionally, the cytotoxic activity of NKL cells against K562 targets was compromised after co-culture with HeLa and SiHa cells, while co-culture with C33A increased the cytotoxic activity of the NKL cells. Conclusions Our results suggest that differential expression of NKG2D-ligands in cervical cancer cell lines might be associated with the down-modulation of NKG2D, as well as with changes in the cytotoxic activity of NKL cells after cell-cell contact with the tumor cells.

  3. Tumor hypoxia modulates podoplanin/CCL21 interactions in CCR7+ NK cell recruitment and CCR7+ tumor cell mobilization.

    Science.gov (United States)

    Tejchman, Anna; Lamerant-Fayel, Nathalie; Jacquinet, Jean-Claude; Bielawska-Pohl, Aleksandra; Mleczko-Sanecka, Katarzyna; Grillon, Catherine; Chouaib, Salem; Ugorski, Maciej; Kieda, Claudine

    2017-05-09

    Podoplanin (PDPN), an O-glycosylated, transmembrane, mucin-type glycoprotein, is expressed by cancer associated fibroblasts (CAFs). In malignant transformation, PDPN is subjected to changes and its role is yet to be established. Here we show that it is involved in modulating the activity of the CCL21/CCR7 chemokine/receptor axis in a hypoxia-dependent manner. In the present model, breast cancer MDA-MB-231 cells and NKL3 cells express the surface CCR7 receptor for CCL21 chemokine which is a potent chemoattractant able to bind to PDPN. The impact of the CCL21/CCR7 axis in the molecular mechanism of the adhesion of NKL3 cells and of MDA-MB-231 breast cancer cells was reduced in a hypoxic tumor environment. In addition to its known effect on migration, CCL21/CCR7 interaction was shown to allow NK cell adhesion to endothelial cells (ECs) and its reduction by hypoxia. A PDPN expressing model of CAFs made it possible to demonstrate the same CCL21/CCR7 axis involvement in the tumor cells to CAFs recognition mechanism through PDPN binding of CCL21. PDPN was induced by hypoxia and its overexpression undergoes a reduction of adhesion, making it an anti-adhesion molecule in the absence of CCL21, in the tumor. CCL21/CCR7 modulated NK cells/ECs and MDA-MB-231 cells/CAF PDPN-dependent interactions were further shown to be linked to hypoxia-dependent microRNAs as miRs: miR-210 and specifically miR-21, miR-29b which influence PDPN expression.

  4. An in vitro co-culture model of esophageal cells identifies ascorbic acid as a modulator of cell competition

    Directory of Open Access Journals (Sweden)

    Gardiner Kristin L

    2011-10-01

    Full Text Available Abstract Background The evolutionary dynamics between interacting heterogeneous cell types are fundamental properties of neoplastic progression but can be difficult to measure and quantify. Cancers are heterogeneous mixtures of mutant clones but the direct effect of interactions between these clones is rarely documented. The implicit goal of most preventive interventions is to bias competition in favor of normal cells over neoplastic cells. However, this is rarely explicitly tested. Here we have developed a cell culture competition model to allow for direct observation of the effect of chemopreventive or therapeutic agents on two interacting cell types. We have examined competition between normal and Barrett's esophagus cell lines, in the hopes of identifying a system that could screen for potential chemopreventive agents. Methods One fluorescently-labeled normal squamous esophageal cell line (EPC2-hTERT was grown in competition with one of four Barrett's esophagus cell lines (CP-A, CP-B, CP-C, CP-D under varying conditions and the outcome of competition measured over 14 days by flow cytometry. Results We demonstrate that ascorbic acid (vitamin C can help squamous cells outcompete Barrett's cells in this system. We are also able to show that ascorbic acid's boost to the relative fitness of squamous cells was increased in most cases by mimicking the pH conditions of gastrointestinal reflux in the lower esophagus. Conclusions This model is able to integrate differential fitness effects on various cell types, allowing us to simultaneously capture effects on interacting cell types without having to perform separate experiments. This model system may be used to screen for new classes of cancer prevention agents designed to modulate the competition between normal and neoplastic cells.

  5. Excited baryons

    International Nuclear Information System (INIS)

    Mukhopadhyay, N.C.

    1986-01-01

    The status of the theory of the low-energy approach to hadron structure is reviewed briefly by surveying a few relevant models. A few examples of tests needed to sort out the predictions of different models pertaining to the quark-gluon structure of hadrons are discussed, and given the resulting physics objectives, a few experimental options for excited baryon research at CFBAF are suggested

  6. Excited baryons

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, N.C.

    1986-01-01

    The status of the theory of the low-energy approach to hadron structure is reviewed briefly by surveying a few relevant models. A few examples of tests needed to sort out the predictions of different models pertaining to the quark-gluon structure of hadrons are discussed, and given the resulting physics objectives, a few experimental options for excited baryon research at CFBAF are suggested. (LEW)

  7. Fisetin and hesperetin induced apoptosis and cell cycle arrest in chronic myeloid leukemia cells accompanied by modulation of cellular signaling.

    Science.gov (United States)

    Adan, Aysun; Baran, Yusuf

    2016-05-01

    Fisetin and hesperetin, naturally occurring flavonoids, have been reported as novel antioxidants with chemopreventive/chemotherapeutic potential against various types of cancer. However, their mechanism of action in CML is still unknown. This particular study aims to evaluate the therapeutic potentials of fisetin and hesperetin and their effects on cell proliferation, apoptosis, and cell cycle progression in human K562 CML cells. The results indicated that fisetin and hesperetin inhibited cell proliferation and triggered programmed cell death in these cells. The latter was confırmed by mitochondrial membrane depolarization and an increase in caspase-3 activation. In addition to that, we have detected S and G2/M cell cycle arrests and G0/G1 arrest upon fisetin and hesperetin treatment, respectively. To identify the altered genes and genetic networks in response to fisetin and hesperetin, whole-genome microarray analysis was performed. The microarray gene profiling analysis revealed some important signaling pathways including JAK/STAT pathway, KIT receptor signaling, and growth hormone receptor signaling that were altered upon fisetin and hesperetin treatment. Moreover, microarray data suggested potential candidate genes for targeted CML therapy. Fisetin and hesperetin significantly modulated the expression of genes involved in cell proliferation and division, apoptosis, cell cycle regulation, and other significant cellular processes such as replication, transcription, and translation. In conclusion, our results suggest that fisetin and hesperetin as potential natural agents for CML therapy.

  8. 17th Workshop on Crystalline Silicon Solar Cells and Modules: Materials and Processes; Workshop Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B. L.

    2007-08-01

    The National Center for Photovoltaics sponsored the 17th Workshop on Crystalline Silicon Solar Cells & Modules: Materials and Processes, held in Vail, CO, August 5-8, 2007. This meeting provided a forum for an informal exchange of technical and scientific information between international researchers in the photovoltaic and relevant non-photovoltaic fields. The theme of this year's meeting was 'Expanding Technology for a Future Powered by Si Photovoltaics.'

  9. H-1 and N-15 resonance assignment of the second fibronectin type III module of the neural cell adhesion molecule

    DEFF Research Database (Denmark)

    Kiselyov, Vladislav V; Berezin, Vladimir; Bock, Elisabeth

    2008-01-01

    We report here the NMR assignment of the second fibronectin type III module of the neural cell adhesion molecule (NCAM). This module has previously been shown to interact with the fibroblast growth factor receptor (FGFR), and the FGFR-binding site was mapped by NMR to the FG-loop region of the mo......We report here the NMR assignment of the second fibronectin type III module of the neural cell adhesion molecule (NCAM). This module has previously been shown to interact with the fibroblast growth factor receptor (FGFR), and the FGFR-binding site was mapped by NMR to the FG-loop region...... of the module. The FG-loop region also contains a putative nucleotide-binding motif, which was shown by NMR to interact with ATP. Furthermore, ATP was demonstrated to inhibit binding of the second F3 module of NCAM to FGFR....

  10. NF-kappa B modulation is involved in celastrol induced human multiple myeloma cell apoptosis.

    Directory of Open Access Journals (Sweden)

    Haiwen Ni

    Full Text Available Celastrol is an active compound extracted from the root bark of the traditional Chinese medicine Tripterygium wilfordii Hook F. To investigate the effect of celastrol on human multiple myeloma cell cycle arrest and apoptosis and explore its molecular mechanism of action. The activity of celastrol on LP-1 cell proliferation was detected by WST-8 assay. The celastrol-induced cell cycle arrest was analyzed by flow cytometry after propidium iodide staining. Nuclear translocation of the nuclear factor kappa B (NF-κB was observed by fluorescence microscope. Celastrol inhibited cell proliferation of LP-1 myeloma cell in a dose-dependent manner with IC50 values of 0.8817 µM, which was mediated through G1 cell cycle arrest and p27 induction. Celastrol induced apoptosis in LP-1 and RPMI 8226 myeloma cells in a time and dose dependent manner, and it involved Caspase-3 activation and NF-κB pathway. Celastrol down-modulated antiapoptotic proteins including Bcl-2 and survivin expression. The expression of NF-κB and IKKa were decreased after celastrol treatment. Celastrol effectively blocked the nuclear translocation of the p65 subunit and induced human multiple myeloma cell cycle arrest and apoptosis by p27 upregulation and NF-kB modulation. It has been demonstrated that the effect of celastrol on NF-kB was HO-1-independent by using zinc protoporphyrin-9 (ZnPPIX, a selective heme oxygenase inhibitor. From the results, it could be inferred that celastrol may be used as a NF-kB inhibitor to inhibit myeloma cell proliferation.

  11. Implementation of a Service-Learning Module in Medical Microbiology and Cell Biology Classes at an Undergraduate Liberal Arts University

    Directory of Open Access Journals (Sweden)

    Maia Larios-Sanz

    2011-03-01

    Full Text Available Here we discuss the implementation of a service-learning module in two upper-division biology classes, Medical Microbiology and Cell Biology. This exciting hands-on learning experience provided our students with an opportunity to extend their learning of in-class topics to a real-life scenario. Students were required to volunteer their time (a minimum of 10 hours in a semester at an under-served clinic in Houston, Texas. As they interacted with the personnel at the clinic, they were asked to identify the most prevalent disease (infectious for Medical Microbiology, and cellular-based for Cell seen at the clinic and, working in groups, come up with educational material in the form of a display or brochure to be distributed to patients. The material was meant to educate patients about the disease in general terms, as well as how to recognize (symptoms, prevent and treat it. Students were required to keep a reflective journal in the form of a blog throughout the semester, and present their final materials to the class orally. Students were surveyed about their opinion of the experience at the end of the semester. The vast majority of student participants felt that the project was a positive experience and that it helped them develop additional skills beyond what they learn in the classroom and understand how lecture topics relate to every day life. Here we discuss the implementation of a service-learning module in two upper division biology classes, Medical Microbiology and Cell Biology. This exciting hands-on learning experience provided our students with an opportunity to extend their learning of in-class topics into a real life scenario. Students were required to volunteer their time (a minimum of 10 hours in a semester at an under-served clinic in Houston, Texas. As they interacted with the personnel at the clinic, they were asked to identify the most prevalent disease (infectious for Medical Microbiology, and cellular-based for Cell seen at the

  12. Out-of-Field Cell Survival Following Exposure to Intensity-Modulated Radiation Fields

    International Nuclear Information System (INIS)

    Butterworth, Karl T.; McGarry, Conor K.; Trainor, Colman; O'Sullivan, Joe M.; Hounsell, Alan R.; Prise, Kevin M.

    2011-01-01

    Purpose: To determine the in-field and out-of-field cell survival of cells irradiated with either primary field or scattered radiation in the presence and absence of intercellular communication. Methods and Materials: Cell survival was determined by clonogenic assay in human prostate cancer (DU145) and primary fibroblast (AGO1552) cells following exposure to different field configurations delivered using a 6-MV photon beam produced with a Varian linear accelerator. Results: Nonuniform dose distributions were delivered using a multileaf collimator (MLC) in which half of the cell population was shielded. Clonogenic survival in the shielded region was significantly lower than that predicted from the linear quadratic model. In both cell lines, the out-of-field responses appeared to saturate at 40%-50% survival at a scattered dose of 0.70 Gy in DU-145 cells and 0.24 Gy in AGO1522 cells. There was an approximately eightfold difference in the initial slopes of the out-of-field response compared with the α-component of the uniform field response. In contrast, cells in the exposed part of the field showed increased survival. These observations were abrogated by direct physical inhibition of cellular communication and by the addition of the inducible nitric oxide synthase inhibitor aminoguanidine known to inhibit intercellular bystander effects. Additional studies showed the proportion of cells irradiated and dose delivered to the shielded and exposed regions of the field to impact on response. Conclusions: These data demonstrate out-of-field effects as important determinants of cell survival following exposure to modulated irradiation fields with cellular communication between differentially irradiated cell populations playing an important role. Validation of these observations in additional cell models may facilitate the refinement of existing radiobiological models and the observations considered important determinants of cell survival.

  13. Osteoactivin regulates head and neck squamous cell carcinoma invasion by modulating matrix metalloproteases.

    Science.gov (United States)

    Arosarena, Oneida A; Barr, Eric W; Thorpe, Ryan; Yankey, Hilary; Tarr, Joseph T; Safadi, Fayez F

    2018-01-01

    Nearly 60% of patients with head and neck squamous cell carcinoma (HNSCC) die of metastases or locoregional recurrence. Metastasis is mediated by cancer cell migration and invasion, which are in part dependent on extracellular matrix degradation by matrix metalloproteinases. Osteoactivin (OA) overexpression plays a role in metastases in several malignancies, and has been shown to upregulate matrix metalloproteinase (MMP) expression and activity. To determine how OA modulates MMP expression and activity in HNSCC, and to investigate OA effects on cell invasion, we assessed effects of OA treatment on MMP mRNA and protein expression, as well as gelatinase and caseinolytic activity in HNSCC cell lines. We assessed the effects of OA gene silencing on MMP expression, gelatinase and caseinolytic activity, and cell invasion. OA treatment had differential effects on MMP mRNA expression. OA treatment upregulated MMP-10 expression in UMSCC14a (p = 0.0431) and SCC15 (p < 0.0001) cells, but decreased MMP-9 expression in UMSCC14a cells (p = 0.0002). OA gene silencing decreased MMP-10 expression in UMSCC12 cells (p = 0.0001), and MMP-3 (p = 0.0005) and -9 (p = 0.0036) expression in SCC25 cells. In SCC15 and SCC25 cells, OA treatment increased MMP-2 (p = 0.0408) and MMP-9 gelatinase activity (p < 0.0001), respectively. OA depletion decreased MMP-2 (p = 0.0023) and -9 (p < 0.0001) activity in SCC25 cells. OA treatment increased 70 kDa caseinolytic activity in UMSCC12 cells consistent with tissue type plasminogen activator (p = 0.0078). OA depletion decreased invasive capacity of UMSCC12 cells (p < 0.0001). OA's effects on MMP expression in HNSCC are variable, and may promote cancer cell invasion. © 2017 Wiley Periodicals, Inc.

  14. Multifractal Desynchronization of the Cardiac Excitable Cell Network During Atrial Fibrillation. I. Multifractal Analysis of Clinical Data

    Directory of Open Access Journals (Sweden)

    Guillaume Attuel

    2018-03-01

    which is innervated by the ANS. In a companion paper (II. Modeling, we propose a mathematical model of a denervated heart where the kinetics of gap junction conductance alone induces a desynchronization of the myocardial excitable cells, accounting for the multifractal spectra found experimentally in the left atrial posterior wall area.

  15. Multifractal Desynchronization of the Cardiac Excitable Cell Network During Atrial Fibrillation. I. Multifractal Analysis of Clinical Data

    Science.gov (United States)

    Attuel, Guillaume; Gerasimova-Chechkina, Evgeniya; Argoul, Francoise; Yahia, Hussein; Arneodo, Alain

    2018-01-01

    innervated by the ANS. In a companion paper (II. Modeling), we propose a mathematical model of a denervated heart where the kinetics of gap junction conductance alone induces a desynchronization of the myocardial excitable cells, accounting for the multifractal spectra found experimentally in the left atrial posterior wall area. PMID:29632492

  16. Near-term markets for PEM fuel cell power modules: industrial vehicles and hydrogen recovery

    International Nuclear Information System (INIS)

    Chintawar, P.S.; Block, G.

    2004-01-01

    'Full text:' Nuvera Fuel Cells, Inc. is a global leader in the development and advancement of multifuel processing and fuel cell technology. With offices located in Italy and the USA, Nuvera is committed to advancing the commercialization of hydrogen fuel cell power modules for industrial vehicles and equipment and stationary applications by 2006, natural gas fuel cell power systems for cogeneration applications by 2007, and on-board gasoline fuel processors and fuel cell stacks for automotive applications by 2010. Nuvera Fuel Cells Europe is ISO 9001:2000 certified for 'Research, Development, Design, Production and Servicing of Fuel Cell Stacks and Fuel Cell Systems.' In the chemical industry, one of the largest operating expenses today is the cost of electricity. For example, caustic soda and chlorine are produced today using industrial membrane electrolysis which is an energy intensive process. Production of 1 metric ton of caustic soda consumes 2.5 MWh of energy. However, about 20% of the electricity consumed can be recovered by converting the hydrogen byproduct of the caustic soda production process into electricity via PEM fuel cells. The accessible market is a function of the economic value of the hydrogen whether flared, used as fuel, or as chemical. Responding to this market need, we are currently developing large hydrogen fuel cell power modules 'Forza' that use excess hydrogen to produce electricity, representing a practical economic alternative to reducing the net electricity cost. Due for commercial launch in 2006, Forza is a low-pressure, steady state, base-load power generation solution that will operate at high efficiency and 100% capacity over a 24-hour period. We believe this premise is also true for chemical and electrochemical plants and companies that convert hydrogen to electricity using renewable sources like windmills or hydropower. The second near-term market that Nuvera is developing utilizes a 5.5 kW hydrogen fueled power module 'H 2 e

  17. Ghrelin modulates testicular germ cells apoptosis and proliferation in adult normal rats

    Energy Technology Data Exchange (ETDEWEB)

    Kheradmand, Arash, E-mail: arashkheradmand@yahoo.com [Department of Clinical Sciences, School of Veterinary Medicine, Lorestan University, P.O. Box: 465, Khorram Abad (Iran, Islamic Republic of); Dezfoulian, Omid [Department of Pathobiology, School of Veterinary Medicine, Lorestan University, Khorram Abad (Iran, Islamic Republic of); Alirezaei, Masoud [Division of Biochemistry, School of Veterinary Medicine, Lorestan University, P.O. Box: 465, Khorram Abad (Iran, Islamic Republic of); Rasoulian, Bahram [Razi Herbal Medicine Research Center, Lorestan University of Medical Sciences, Khorram Abad (Iran, Islamic Republic of)

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer Spermatogenesis is closely associated with the balance between germ cells proliferation and apoptosis. Black-Right-Pointing-Pointer Numerous studies have documented the direct action of ghrelin in the modulation of apoptosis in different cell types. Black-Right-Pointing-Pointer Ghrelin may be considered as a modulator of spermatogenesis in normal adult rats. Black-Right-Pointing-Pointer Ghrelin may be potentially implicated for abnormal spermatogenesis in some testicular germ cell tumors. -- Abstract: Under normal condition in the most mammals, spermatogenesis is closely associated with the balance between germ cells proliferation and apoptosis. The present study was designed to determine the effects of ghrelin treatment on in vivo quality and quantity expression of apoptosis and proliferation specific indices in rat testicular germ cells. Twenty eight adult normal rats were subdivided into equal control and treatment groups. Treatment group received 3 nmol of ghrelin as subcutaneous injection for 30 consecutive days or vehicle to the control animals. The rats from each group (n = 7) were killed on days 10 and 30 and their testes were taken for immunocytochemical evaluation and caspase-3 assay. Immunohistochemical analysis indicated that the accumulations of Bax and PCNA peptides are generally more prominent in spermatocytes and spermatogonia of both groups. Likewise, the mean percentage of immunoreactive spermatocytes against Bax increased (P < 0.01) in the ghrelin-treated group on day 10, while despite of 30% increment in the Bax level of spermatocytes in the treated rats on day 30, however, it was not statistically significant. During the experimental period, only a few spermatogonia represented Bax expression and the changes of Bax immunolabling cells were negligible upon ghrelin treatment. Likewise, there were immunostaining cells against Bcl-2 in each germ cell neither in the control nor in the treated animals. In fact

  18. Lactobacilli differentially modulate expression of cytokines and maturation surface markers in murine dendritic cells

    DEFF Research Database (Denmark)

    Christensen, Hanne Risager; Frøkiær, Hanne; Pestka, J.J.

    2002-01-01

    Dendritic cells (DC) play a pivotal immunoregulatory role in the Th1, Th2, and Th3 cell balance and are present throughout the gastrointestinal tract. Thus, DC may be targets for modulation by gut microbes, including ingested probiotics. In the present study, we tested the hypothesis that species...... reduced L casei-induced up-regulation of B7-2. These results suggest that different species of Lactobacillus exert very different DC activation patterns and, furthermore, at least one species may be capable of inhibiting activities of other species in the genus. Thus, the potential exists for Th1/Th2/Th3...

  19. Modulation of Autoimmune T-Cell Memory by Stem Cell Educator Therapy: Phase 1/2 Clinical Trial.

    Science.gov (United States)

    Delgado, Elias; Perez-Basterrechea, Marcos; Suarez-Alvarez, Beatriz; Zhou, Huimin; Revuelta, Eva Martinez; Garcia-Gala, Jose Maria; Perez, Silvia; Alvarez-Viejo, Maria; Menendez, Edelmiro; Lopez-Larrea, Carlos; Tang, Ruifeng; Zhu, Zhenlong; Hu, Wei; Moss, Thomas; Guindi, Edward; Otero, Jesus; Zhao, Yong

    2015-12-01

    Type 1 diabetes (T1D) is a T cell-mediated autoimmune disease that causes a deficit of pancreatic islet β cells. The complexities of overcoming autoimmunity in T1D have contributed to the challenges the research community faces when devising successful treatments with conventional immune therapies. Overcoming autoimmune T cell memory represents one of the key hurdles. In this open-label, phase 1/phase 2 study, Caucasian T1D patients (N = 15) received two treatments with the Stem Cell Educator (SCE) therapy, an approach that uses human multipotent cord blood-derived multipotent stem cells (CB-SCs). SCE therapy involves a closed-loop system that briefly treats the patient's lymphocytes with CB-SCs in vitro and returns the "educated" lymphocytes (but not the CB-SCs) into the patient's blood circulation. This study is registered with ClinicalTrials.gov, NCT01350219. Clinical data demonstrated that SCE therapy was well tolerated in all subjects. The percentage of naïve CD4(+) T cells was significantly increased at 26 weeks and maintained through the final follow-up at 56 weeks. The percentage of CD4(+) central memory T cells (TCM) was markedly and constantly increased at 18 weeks. Both CD4(+) effector memory T cells (TEM) and CD8(+) TEM cells were considerably decreased at 18 weeks and 26 weeks respectively. Additional clinical data demonstrated the modulation of C-C chemokine receptor 7 (CCR7) expressions on naïve T, TCM, and TEM cells. Following two treatments with SCE therapy, islet β-cell function was improved and maintained in individuals with residual β-cell function, but not in those without residual β-cell function. Current clinical data demonstrated the safety and efficacy of SCE therapy in immune modulation. SCE therapy provides lasting reversal of autoimmune memory that could improve islet β-cell function in Caucasian subjects. Obra Social "La Caixa", Instituto de Salud Carlos III, Red de Investigación Renal, European Union FEDER Funds, Principado de

  20. Heme oxygenase-1 (HO-1 expression in prostate cancer cells modulates the oxidative response in bone cells.

    Directory of Open Access Journals (Sweden)

    Mercedes Ferrando

    Full Text Available Prostate cancer (PCa is a leading cause of death among males. It is currently estimated that inflammatory responses are linked to 15-20% of all deaths from cancer worldwide. PCa is dominated by complications arising from metastasis to the bone where the tumor cells interact with the bone microenvironment impairing the balance between bone formation and degradation. However, the molecular nature of this interaction is not completely understood. Heme oxygenase-1 (HO-1 counteracts oxidative damage and inflammation. Previous studies from our laboratory showed that HO-1 is implicated in PCa, demonstrating that endogenous HO-1 inhibits bone derived-prostate cancer cells proliferation, invasion and migration and decreases tumor growth and angiogenesis in vivo. The aim of this work was to analyze the impact of HO-1 modulated PCa cells on osteoblasts proliferation in vitro and on bone remodeling in vivo. Using a co-culture system of PC3 cells with primary mice osteoblasts (PMOs, we demonstrated that HO-1 pharmacological induction (hemin treatment abrogated the diminution of PMOs proliferation induced by PCa cells and decreased the expression of osteoclast-modulating factors in osteoblasts. No changes were detected in the expression of genes involved in osteoblasts differentiation. However, co-culture of hemin pre-treated PC3 cells (PC3 Hem with PMOs provoked an oxidative status and activated FoxO signaling in osteoblasts. The percentage of active osteoblasts positive for HO-1 increased in calvarias explants co-cultured with PC3 Hem cells. Nuclear HO-1 expression was detected in tumors generated by in vivo bone injection of HO-1 stable transfected PC3 (PC3HO-1 cells in the femur of SCID mice. These results suggest that HO-1 has the potential to modify the bone microenvironment impacting on PCa bone metastasis.

  1. Myc Decoy Oligodeoxynucleotide Inhibits Growth and Modulates Differentiation of Mouse Embryonic Stem Cells as a Model of Cancer Stem Cells.

    Science.gov (United States)

    Johari, Behrooz; Ebrahimi-Rad, Mina; Maghsood, Faezeh; Lotfinia, Majid; Saltanatpouri, Zohreh; Teimoori-Toolabi, Ladan; Sharifzadeh, Zahra; Karimipoor, Morteza; Kadivar, Mehdi

    2017-01-01

    Myc (c-Myc) alone activates the embryonic stem cell-like transcriptional module in both normal and transformed cells. Its dysregulation might lead to increased cancer stem cells (CSCs) population in some tumor cells. In order to investigate the potential of Myc decoy oligodeoxynucleotides for differentiation therapy, mouse embryonic stem cells (mESCs) were used in this study as a model of CSCs. To our best of knowledge this is the first report outlining the application of Myc decoy in transcription factor decoy "TFD" strategy for inducing differentiation in mESCs. A 20-mer double-stranded Myc transcription factor decoy and scrambled oligodeoxynucleotides (ODNs) were designed, analyzed by electrophoretic mobility shift (EMSA) assay and transfected into the mESCs under 2 inhibitors (2i) condition. Further investigations were carried out using fluorescence and confocal microscopy, cell proliferation and apoptosis analysis, alkaline phosphatase and embryoid body formation assay, real-time PCR and western blotting. EMSA data showed that Myc decoy ODNs bound specifically to c-Myc protein. They were found to be localized in both cytoplasm and nucleus of mESCs. Our results revealed the potential capability of Myc decoy ODNs to decrease cell viability by (16.1±2%), to increase the number of cells arrested in G0/G1 phases and apoptosis by (14.2±3.1%) and (12.1±3.2%), respectively regarding the controls. Myc decoy could also modulate differentiation in mESCs despite the presence of 2i/LIF in our medium the presence of 2i/LIF in our medium. The optimized Myc decoy ODNs approach might be considered as a promising alternative strategy for differentiation therapy investigations. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  2. MicroRNA modulation induced by AICA ribonucleotide in J1 mouse ES cells.

    Directory of Open Access Journals (Sweden)

    Xiaoyan Shi

    Full Text Available ES cells can propagate indefinitely, maintain self-renewal, and differentiate into almost any cell type of the body. These properties make them valuable in the research of embryonic development, regenerative medicine, and organ transplantation. MicroRNAs (miRNAs are considered to have essential functions in the maintenance and differentiation of embryonic stem cells (ES cells. It was reported that, strong external stimuli, such as a transient low-pH and hypoxia stress, were conducive to the formation of induced pluripotent stem cells (iPS cells. AICA ribonucleotide (AICAR is an AMP-activated protein kinase activator, which can let cells in the state of energy stress. We have demonstrated that AICAR can maintain the pluripotency of J1 mouse ES cells through modulating protein expression in our previous research, but its effects on ES cell miRNA expression remain unknown. In this study, we conducted small RNA high-throughput sequencing to investigate AICAR influence on J1 mouse ES cells by comparing the miRNA expression patterns of the AICAR-treated cells and those without treatment. The result showed that AICAR can significantly modulate the expression of multiple miRNAs, including those have crucial functions in ES cell development. Some differentially expressed miRNAs were selected and confirmed by real-time PCR. For the differently expressed miRNAs identified, further study was conducted regarding the pluripotency and differentiation associated miRNAs with their targets. Moreover, miR-134 was significantly down-regulated after AICAR treatment, and this was suggested to be directly associated with the up-regulated pluripotency markers, Nanog and Sox2. Lastly, Myc was significantly down-regulated after AICAR treatment; therefore, we predicted miRNAs that may target Myc and identified that AICAR induced up-regulation of miR-34a, 34b, and 34c can repress Myc expression in J1 mouse ES cells. Taken together, our study provide a new mechanism for

  3. Two pore channel 2 differentially modulates neural differentiation of mouse embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Zhe-Hao Zhang

    Full Text Available Nicotinic acid adenine dinucleotide phosphate (NAADP is an endogenous Ca(2+ mobilizing nucleotide presented in various species. NAADP mobilizes Ca(2+ from acidic organelles through two pore channel 2 (TPC2 in many cell types and it has been previously shown that NAADP can potently induce neuronal differentiation in PC12 cells. Here we examined the role of TPC2 signaling in the neural differentiation of mouse embryonic stem (ES cells. We found that the expression of TPC2 was markedly decreased during the initial ES cell entry into neural progenitors, and the levels of TPC2 gradually rebounded during the late stages of neurogenesis. Correspondingly, TPC2 knockdown accelerated mouse ES cell differentiation into neural progenitors but inhibited these neural progenitors from committing to neurons. Overexpression of TPC2, on the other hand, inhibited mouse ES cell from entering the early neural lineage. Interestingly, TPC2 knockdown had no effect on the differentiation of astrocytes and oligodendrocytes of mouse ES cells. Taken together, our data indicate that TPC2 signaling plays a temporal and differential role in modulating the neural lineage entry of mouse ES cells, in that TPC2 signaling inhibits ES cell entry to early neural progenitors, but is required for late neuronal differentiation.

  4. Potentiating the antitumour response of CD8+ T cells by modulating cholesterol metabolism

    Science.gov (United States)

    Yang, Wei; Bai, Yibing; Xiong, Ying; Zhang, Jin; Chen, Shuokai; Zheng, Xiaojun; Meng, Xiangbo; Li, Lunyi; Wang, Jing; Xu, Chenguang; Yan, Chengsong; Wang, Lijuan; Chang, Catharine C. Y.; Chang, Ta-Yuan; Zhang, Ti; Zhou, Penghui; Song, Bao-Liang; Liu, Wanli; Sun, Shao-cong; Liu, Xiaolong; Li, Bo-liang; Xu, Chenqi

    2016-01-01

    CD8+ T cells have a central role in antitumour immunity, but their activity is suppressed in the tumour microenvironment1–4. Reactivating the cytotoxicity of CD8+ T cells is of great clinical interest in cancer immunotherapy. Here we report a new mechanism by which the antitumour response of mouse CD8+ T cells can be potentiated by modulating cholesterol metabolism. Inhibiting cholesterol esterification in T cells by genetic ablation or pharmacological inhibition of ACAT1, a key cholesterol esterification enzyme5, led to potentiated effector function and enhanced proliferation of CD8+ but not CD4+ T cells. This is due to the increase in the plasma membrane cholesterol level of CD8+ T cells, which causes enhanced T-cell receptor clustering and signalling as well as more efficient formation of the immunological synapse. ACAT1-deficient CD8+ T cells were better than wild-type CD8+ T cells at controlling melanoma growth and metastasis in mice. We used the ACAT inhibitor avasimibe, which was previously tested in clinical trials for treating atherosclerosis and showed a good human safety profile6,7, to treat melanoma in mice and observed a good antitumour effect. A combined therapy of avasimibe plus an anti-PD-1 antibody showed better efficacy than monotherapies in controlling tumour progression. ACAT1, an established target for atherosclerosis, is therefore also a potential target for cancer immunotherapy. PMID:26982734

  5. Integrin-linked kinase interactions with ELMO2 modulate cell polarity.

    Science.gov (United States)

    Ho, Ernest; Irvine, Tames; Vilk, Gregory J A; Lajoie, Gilles; Ravichandran, Kodi S; D'Souza, Sudhir J A; Dagnino, Lina

    2009-07-01

    Cell polarization is a key prerequisite for directed migration during development, tissue regeneration, and metastasis. Integrin-linked kinase (ILK) is a scaffold protein essential for cell polarization, but very little is known about the precise mechanisms whereby ILK modulates polarization in normal epithelia. Elucidating these mechanisms is essential to understand tissue morphogenesis, transformation, and repair. Here we identify a novel ILK protein complex that includes Engulfment and Cell Motility 2 (ELMO2). We also demonstrate the presence of RhoG in ILK-ELMO2 complexes, and the localization of this multiprotein species specifically to the leading lamellipodia of polarized cells. Significantly, the ability of RhoG to bind ELMO is crucial for ILK induction of cell polarization, and the joint expression of ILK and ELMO2 synergistically promotes the induction of front-rear polarity and haptotactic migration. This places RhoG-ELMO2-ILK complexes in a key position for the development of cell polarity and forward movement. Although ILK is a component of many diverse multiprotein species that may contribute to cell polarization, expression of dominant-negative ELMO2 mutants is sufficient to abolish the ability of ILK to promote cell polarization. Thus, its interaction with ELMO2 and RhoG is essential for the ability of ILK to induce front-rear cell polarity.

  6. Highly Efficient LiYF4:Yb(3+), Er(3+) Upconversion Single Crystal under Solar Cell Spectrum Excitation and Photovoltaic Application.

    Science.gov (United States)

    Chen, Xu; Xu, Wen; Song, Hongwei; Chen, Cong; Xia, Haiping; Zhu, Yongsheng; Zhou, Donglei; Cui, Shaobo; Dai, Qilin; Zhang, Jiazhong

    2016-04-13

    Luminescent upconversion is a promising way to harvest near-infrared (NIR) sunlight and transforms it into visible light that can be directly absorbed by active materials of solar cells and improve their power conversion efficiency (PCE). However, it is still a great challenge to effectively improve the PCE of solar cells with the assistance of upconversion. In this work, we demonstrate the application of the transparent LiYF4:Yb(3+), Er(3+) single crystal as an independent luminescent upconverter to improve the PCE of perovskite solar cells. The LiYF4:Yb(3+), Er(3+) single crystal is prepared by an improved Bridgman method, and its internal quantum efficiency approached to 5.72% under 6.2 W cm(-2) 980 nm excitation. The power-dependent upconversion luminescence indicated that under the excitation of simulated sunlight the (4)F(9/2)-(4)I(15/2) red emission originally results from the cooperation of a 1540 nm photon and a 980 nm photon. Furthermore, when the single crystal is placed in front of the perovskite solar cells, the PCE is enhanced by 7.9% under the irradiation of simulated sunlight by 7-8 solar constants. This work implies the upconverter not only can serve as proof of principle for improving PCE of solar cells but also is helpful to practical application.

  7. RNA-based, transient modulation of gene expression in human haematopoietic stem and progenitor cells

    Science.gov (United States)

    Diener, Yvonne; Jurk, Marion; Kandil, Britta; Choi, Yeong-Hoon; Wild, Stefan; Bissels, Ute; Bosio, Andreas

    2015-01-01

    Modulation of gene expression is a useful tool to study the biology of haematopoietic stem and progenitor cells (HSPCs) and might also be instrumental to expand these cells for therapeutic approaches. Most of the studies so far have employed stable gene modification by viral vectors that are burdensome when translating protocols into clinical settings. Our study aimed at exploring new ways to transiently modify HSPC gene expression using non-integrating, RNA-based molecules. First, we tested different methods to deliver these molecules into HSPCs. The delivery of siRNAs with chemical transfection methods such as lipofection or cationic polymers did not lead to target knockdown, although we observed more than 90% fluorescent cells using a fluorochrome-coupled siRNA. Confocal microscopic analysis revealed that despite extensive washing, siRNA stuck to or in the cell surface, thereby mimicking a transfection event. In contrast, electroporation resulted in efficient, siRNA-mediated protein knockdown. For transient overexpression of proteins, we used optimised mRNA molecules with modified 5′- and 3′-UTRs. Electroporation of mRNA encoding GFP resulted in fast, efficient and persistent protein expression for at least seven days. Our data provide a broad-ranging comparison of transfection methods for hard-to-transfect cells and offer new opportunities for DNA-free, non-integrating gene modulation in HSPCs. PMID:26599627

  8. Activated H-Ras regulates hematopoietic cell survival by modulating Survivin

    International Nuclear Information System (INIS)

    Fukuda, Seiji; Pelus, Louis M.

    2004-01-01

    Survivin expression and Ras activation are regulated by hematopoietic growth factors. We investigated whether activated Ras could circumvent growth factor-regulated Survivin expression and if a Ras/Survivin axis mediates growth factor independent survival and proliferation in hematopoietic cells. Survivin expression is up-regulated by IL-3 in Ba/F3 and CD34 + cells and inhibited by the Ras inhibitor, farnesylthiosalicylic acid. Over-expression of constitutively activated H-Ras (CA-Ras) in Ba/F3 cells blocked down-modulation of Survivin expression, G 0 /G 1 arrest, and apoptosis induced by IL-3 withdrawal, while dominant-negative (DN) H-Ras down-regulated Survivin. Survivin disruption by DN T34A Survivin blocked CA-Ras-induced IL-3-independent cell survival and proliferation; however, it did not affect CA-Ras-mediated enhancement of S-phase, indicating that the anti-apoptotic activity of CA-Ras is Survivin dependent while its S-phase enhancing effect is not. These results indicate that CA-Ras modulates Survivin expression independent of hematopoietic growth factors and that a CA-Ras/Survivin axis regulates survival and proliferation of transformed hematopoietic cells

  9. Akt1 intramitochondrial cycling is a crucial step in the redox modulation of cell cycle progression.

    Directory of Open Access Journals (Sweden)

    Valeria Gabriela Antico Arciuch

    2009-10-01

    Full Text Available Akt is a serine/threonine kinase involved in cell proliferation, apoptosis, and glucose metabolism. Akt is differentially activated by growth factors and oxidative stress by sequential phosphorylation of Ser(473 by mTORC2 and Thr(308 by PDK1. On these bases, we investigated the mechanistic connection of H(2O(2 yield, mitochondrial activation of Akt1 and cell cycle progression in NIH/3T3 cell line with confocal microscopy, in vivo imaging, and directed mutagenesis. We demonstrate that modulation by H(2O(2 entails the entrance of cytosolic P-Akt1 Ser(473 to mitochondria, where it is further phosphorylated at Thr(308 by constitutive PDK1. Phosphorylation of Thr(308 in mitochondria determines Akt1 passage to nuclei and triggers genomic post-translational mechanisms for cell proliferation. At high H(2O(2, Akt1-PDK1 association is disrupted and P-Akt1 Ser(473 accumulates in mitochondria in detriment to nuclear translocation; accordingly, Akt1 T308A is retained in mitochondria. Low Akt1 activity increases cytochrome c release to cytosol leading to apoptosis. As assessed by mass spectra, differential H(2O(2 effects on Akt1-PDK interaction depend on the selective oxidation of Cys(310 to sulfenic or cysteic acids. These results indicate that Akt1 intramitochondrial-cycling is central for redox modulation of cell fate.

  10. Protein conservation and variation suggest mechanisms of cell type-specific modulation of signaling pathways.

    Directory of Open Access Journals (Sweden)

    Martin H Schaefer

    2014-06-01

    Full Text Available Many proteins and signaling pathways are present in most cell types and tissues and yet perform specialized functions. To elucidate mechanisms by which these ubiquitous pathways are modulated, we overlaid information about cross-cell line protein abundance and variability, and evolutionary conservation onto functional pathway components and topological layers in the pathway hierarchy. We found that the input (receptors and the output (transcription factors layers evolve more rapidly than proteins in the intermediary transmission layer. In contrast, protein expression variability decreases from the input to the output layer. We observed that the differences in protein variability between the input and transmission layer can be attributed to both the network position and the tendency of variable proteins to physically interact with constitutively expressed proteins. Differences in protein expression variability and conservation are also accompanied by the tendency of conserved and constitutively expressed proteins to acquire somatic mutations, while germline mutations tend to occur in cell type-specific proteins. Thus, conserved core proteins in the transmission layer could perform a fundamental role in most cell types and are therefore less tolerant to germline mutations. In summary, we propose that the core signal transmission machinery is largely modulated by a variable input layer through physical protein interactions. We hypothesize that the bow-tie organization of cellular signaling on the level of protein abundance variability contributes to the specificity of the signal response in different cell types.

  11. Tumor Architecture and Notch Signaling Modulate Drug Response in Basal Cell Carcinoma.

    Science.gov (United States)

    Eberl, Markus; Mangelberger, Doris; Swanson, Jacob B; Verhaegen, Monique E; Harms, Paul W; Frohm, Marcus L; Dlugosz, Andrzej A; Wong, Sunny Y

    2018-02-12

    Hedgehog (Hh) pathway inhibitors such as vismodegib are highly effective for treating basal cell carcinoma (BCC); however, residual tumor cells frequently persist and regenerate the primary tumor upon drug discontinuation. Here, we show that BCCs are organized into two molecularly and functionally distinct compartments. Whereas interior Hh + /Notch + suprabasal cells undergo apoptosis in response to vismodegib, peripheral Hh +++ /Notch - basal cells survive throughout treatment. Inhibiting Notch specifically promotes tumor persistence without causing drug resistance, while activating Notch is sufficient to regress already established lesions. Altogether, these findings suggest that the three-dimensional architecture of BCCs establishes a natural hierarchy of drug response in the tumor and that this hierarchy can be overcome, for better or worse, by modulating Notch. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Manipulating neuronal circuits with endogenous and recombinant cell-surface tethered modulators

    Directory of Open Access Journals (Sweden)

    Mandë Holford

    2009-10-01

    Full Text Available Neuronal circuits depend on the precise regulation of cell-surface receptors and ion channels. An ongoing challenge in neuroscience research is deciphering the functional contribution of specific receptors and ion channels using engineered modulators. A novel strategy, termed “tethered toxins”, was recently developed to characterize neuronal circuits using the evolutionary derived selectivity of venom peptide toxins and endogenous peptide ligands, such as lynx1 prototoxins. Herein, the discovery and engineering of cell-surface tethered peptides is reviewed, with particular attention given to their cell-autonomy, modular composition, and genetic targeting in different model organisms. The relative ease with which tethered peptides can be engineered, coupled with the increasing number of neuroactive venom toxins and ligand peptides being discovered, imply a multitude of potentially innovative applications for manipulating neuronal circuits and tissue-specific cell networks, including treatment of disorders caused by malfunction of receptors and ion channels.

  13. Development of an empirical dynamic model for a Nexa PEM fuel cell power module

    Energy Technology Data Exchange (ETDEWEB)

    Soltani, Mehdi; Mohammad Taghi Bathaee, S. [Power Systems Laboratory, Department of Electrical Engineering, K.N. Toosi University of Technology, 16317-14191 Tehran (Iran)

    2010-12-15

    The goal of this study is to develop a fuel cell model which is capable of characterizing fuel cell steady-state performance as well as dynamic behavior. In this paper a new dynamic model of a 1.2 kW Polymer Electrolyte Membrane Fuel Cell (PEMFC) is developed and validated through a series of experiments. The experimental results have been obtained from a Nexa trademark PEM fuel cell power module under different load conditions. Based on this model, a simulator software package has been developed using the MATLAB {sup registered} and Simulink {sup registered} software and simulation results have been carried out. The proposed model exhibits good agreement with experiment results in steady-state and dynamic performance. (author)

  14. Salmonella modulation of host cell gene expression promotes its intracellular growth.

    Directory of Open Access Journals (Sweden)

    Sebastian Hannemann

    Full Text Available Salmonella Typhimurium has evolved a complex functional interface with its host cell largely determined by two type III secretion systems (T3SS, which through the delivery of bacterial effector proteins modulate a variety of cellular processes. We show here that Salmonella Typhimurium infection of epithelial cells results in a profound transcriptional reprogramming that changes over time. This response is triggered by Salmonella T3SS effector proteins, which stimulate unique signal transduction pathways leading to STAT3 activation. We found that the Salmonella-stimulated changes in host cell gene expression are required for the formation of its specialized vesicular compartment that is permissive for its intracellular replication. This study uncovers a cell-autonomous process required for Salmonella pathogenesis potentially opening up new avenues for the development of anti-infective strategies that target relevant host pathways.

  15. Salmonella modulation of host cell gene expression promotes its intracellular growth.

    Science.gov (United States)

    Hannemann, Sebastian; Gao, Beile; Galán, Jorge E

    2013-01-01

    Salmonella Typhimurium has evolved a complex functional interface with its host cell largely determined by two type III secretion systems (T3SS), which through the delivery of bacterial effector proteins modulate a variety of cellular processes. We show here that Salmonella Typhimurium infection of epithelial cells results in a profound transcriptional reprogramming that changes over time. This response is triggered by Salmonella T3SS effector proteins, which stimulate unique signal transduction pathways leading to STAT3 activation. We found that the Salmonella-stimulated changes in host cell gene expression are required for the formation of its specialized vesicular compartment that is permissive for its intracellular replication. This study uncovers a cell-autonomous process required for Salmonella pathogenesis potentially opening up new avenues for the development of anti-infective strategies that target relevant host pathways.

  16. The modulation of stem cell behaviors by functionalized nanoceramic coatings on Ti-based implants

    Directory of Open Access Journals (Sweden)

    Xiangmei Liu

    2016-09-01

    Full Text Available Nanoceramic coating on the surface of Ti-based metallic implants is a clinical potential option in orthopedic surgery. Stem cells have been found to have osteogenic capabilities. It is necessary to study the influences of functionalized nanoceramic coatings on the differentiation and proliferation of stem cells in vitro or in vivo. In this paper, we summarized the recent advance on the modulation of stem cells behaviors through controlling the properties of nanoceramic coatings, including surface chemistry, surface roughness and microporosity. In addition, mechanotransduction pathways have also been discussed to reveal the interaction mechanisms between the stem cells and ceramic coatings on Ti-based metals. In the final part, the osteoinduction and osteoconduction of ceramic coating have been also presented when it was used as carrier of BMPs in new bone formation.

  17. Improved ion acceleration via laser surface plasma waves excitation

    Energy Technology Data Exchange (ETDEWEB)

    Bigongiari, A. [CEA/DSM/LSI, CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France); TIPS/LULI, Université Paris 6, CNRS, CEA, Ecole Polytechnique, 3, rue Galilée, 94200 Ivry-sur-Seine (France); Raynaud, M. [CEA/DSM/LSI, CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France); Riconda, C. [TIPS/LULI, Université Paris 6, CNRS, CEA, Ecole Polytechnique, 3, rue Galilée, 94200 Ivry-sur-Seine (France); Héron, A. [CPHT, CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France)

    2013-05-15

    The possibility of enhancing the emission of the ions accelerated in the interaction of a high intensity ultra-short (<100 fs) laser pulse with a thin target (<10λ{sub 0}), via surface plasma wave excitation is investigated. Two-dimensional particle-in-cell simulations are performed for laser intensities ranging from 10{sup 19} to 10{sup 20} Wcm{sup −2}μm{sup 2}. The surface wave is resonantly excited by the laser via the coupling with a modulation at the target surface. In the cases where the surface wave is excited, we find an enhancement of the maximum ion energy of a factor ∼2 compared to the cases where the target surface is flat.

  18. Protease-activated receptor 2 modulates proliferation and invasion of oral squamous cell carcinoma cells.

    Science.gov (United States)

    Al-Eryani, Kamal; Cheng, Jun; Abé, Tatsuya; Maruyama, Satoshi; Yamazaki, Manabu; Babkair, Hamzah; Essa, Ahmed; Saku, Takashi

    2015-07-01

    Based on our previous finding that protease-activated receptor 2 (PAR-2) regulates hemophagocytosis of oral squamous cell carcinoma (SCC) cells, which induces their heme oxygenase 1-dependent keratinization, we have formulated a hypothesis that PAR-2 functions in wider activities of SCC cells. To confirm this hypothesis, we investigated immunohistochemical profiles of PAR-2 in oral SCC tissues and its functional roles in cell proliferation and invasion in SCC cells in culture. The PAR-2 expression modes were determined in 48 surgical tissue specimens of oral SCC. Using oral SCC-derived cell systems, we determined both gene and protein expression levels of PAR-2. SCC cell proliferation and invasive properties were also examined in conditions in which PAR-2 was activated by the synthetic peptide SLIGRL. PAR-2 was immunolocalized in oral SCC and carcinoma in situ cells, especially in those on the periphery of carcinoma cell foci (100% of cases), but not in normal oral epithelia. Its expression at both gene and protein levels was confirmed in 3 oral SCC cell lines including ZK-1. Activation of PAR-2 induced ZK-1 cell proliferation in a dose-dependent manner. PAR-2-activated ZK-1 cells invaded faster than nonactivated ones. The expression of PAR-2 is specific to oral malignancies, and PAR-2 regulates the growth and invasion of oral SCC cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Convergent modulation of singlet and triplet excited states of phosphine-oxide hosts through the management of molecular structure and functional-group linkages for low-voltage-driven electrophosphorescence.

    Science.gov (United States)

    Han, Chunmiao; Zhang, Zhensong; Xu, Hui; Xie, Guohua; Li, Jing; Zhao, Yi; Deng, Zhaopeng; Liu, Shiyong; Yan, Pengfei

    2013-01-02

    The controllable tuning of the excited states in a series of phosphine-oxide hosts (DPExPOCzn) was realized through introducing carbazolyl and diphenylphosphine-oxide (DPPO) moieties to adjust the frontier molecular orbitals, molecular rigidity, and the location of the triplet excited states by suppressing the intramolecular interplay of the combined multi-insulating and meso linkage. On increasing the number of substituents, simultaneous lowering of the first singlet energy levels (S(1)) and raising of the first triplet energy levels (T(1), about 3.0 eV) were achieved. The former change was mainly due to the contribution of the carbazolyl group to the HOMOs and the extended conjugation. The latter change was due to an enhanced molecular rigidity and the shift of the T(1) states from the diphenylether group to the carbazolyl moieties. This kind of convergent modulation of excited states not only facilitates the exothermic energy transfer to the dopants in phosphorescent organic light-emitting diodes (PHOLEDs), but also realizes the fine-tuning of electrical properties to achieve the balanced carrier injection and transportation in the emitting layers. As the result, the favorable performance of blue-light-emitting PHOLEDs was demonstrated, including much-lower driving voltages of 2.6 V for onset and 3.0 V at 100 cd m(-2), as well as a remarkably improved E.Q.E. of 12.6%. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. MS4a4B, a CD20 homologue in T cells, inhibits T cell propagation by modulation of cell cycle.

    Directory of Open Access Journals (Sweden)

    Hui Xu

    2010-11-01

    Full Text Available MS4a4B, a CD20 homologue in T cells, is a novel member of the MS4A gene family in mice. The MS4A family includes CD20, FcεRIβ, HTm4 and at least 26 novel members that are characterized by their structural features: with four membrane-spanning domains, two extracellular domains and two cytoplasmic regions. CD20, FcεRIβ and HTm4 have been found to function in B cells, mast cells and hematopoietic cells respectively. However, little is known about the function of MS4a4B in T cell regulation. We demonstrate here that MS4a4B negatively regulates mouse T cell proliferation. MS4a4B is highly expressed in primary T cells, natural killer cells (NK and some T cell lines. But its expression in all malignant T cells, including thymoma and T hybridoma tested, was silenced. Interestingly, its expression was regulated during T cell activation. Viral vector-driven overexpression of MS4a4B in primary T cells and EL4 thymoma cells reduced cell proliferation. In contrast, knockdown of MS4a4B accelerated T cell proliferation. Cell cycle analysis showed that MS4a4B regulated T cell proliferation by inhibiting entry of the cells into S-G2/M phase. MS4a4B-mediated inhibition of cell cycle was correlated with upregulation of Cdk inhibitory proteins and decreased levels of Cdk2 activity, subsequently leading to inhibition of cell cycle progression. Our data indicate that MS4a4B negatively regulates T cell proliferation. MS4a4B, therefore, may serve as a modulator in the negative-feedback regulatory loop of activated T cells.

  1. MS4a4B, a CD20 homologue in T cells, inhibits T cell propagation by modulation of cell cycle.

    Science.gov (United States)

    Xu, Hui; Yan, Yaping; Williams, Mark S; Carey, Gregory B; Yang, Jingxian; Li, Hongmei; Zhang, Guang-Xian; Rostami, Abdolmohamad

    2010-11-01

    MS4a4B, a CD20 homologue in T cells, is a novel member of the MS4A gene family in mice. The MS4A family includes CD20, FcεRIβ, HTm4 and at least 26 novel members that are characterized by their structural features: with four membrane-spanning domains, two extracellular domains and two cytoplasmic regions. CD20, FcεRIβ and HTm4 have been found to function in B cells, mast cells and hematopoietic cells respectively. However, little is known about the function of MS4a4B in T cell regulation. We demonstrate here that MS4a4B negatively regulates mouse T cell proliferation. MS4a4B is highly expressed in primary T cells, natural killer cells (NK) and some T cell lines. But its expression in all malignant T cells, including thymoma and T hybridoma tested, was silenced. Interestingly, its expression was regulated during T cell activation. Viral vector-driven overexpression of MS4a4B in primary T cells and EL4 thymoma cells reduced cell proliferation. In contrast, knockdown of MS4a4B accelerated T cell proliferation. Cell cycle analysis showed that MS4a4B regulated T cell proliferation by inhibiting entry of the cells into S-G2/M phase. MS4a4B-mediated inhibition of cell cycle was correlated with upregulation of Cdk inhibitory proteins and decreased levels of Cdk2 activity, subsequently leading to inhibition of cell cycle progression. Our data indicate that MS4a4B negatively regulates T cell proliferation. MS4a4B, therefore, may serve as a modulator in the negative-feedback regulatory loop of activated T cells.

  2. Effects of Redox Modulation on Cell Proliferation, Viability, and Migration in Cultured Rat and Human Tendon Progenitor Cells

    Directory of Open Access Journals (Sweden)

    Yuk Wa Lee

    2017-01-01

    Full Text Available Tendon healing is slow and usually results in inferior fibrotic tissue formation. Recently, application of tendon derived stem cells (TDSCs improved tendon healing in animal studies. In a chicken model, local injection of antioxidants reduced tendon adhesion after tendon injury. An in vitro study demonstrated that supplementation of H2O2 reduced tenogenic marker expression in TDSCs. These findings suggested that the possibility of TDSCs is involved in tendon healing and the cellular activities of TDSCs might be affected by oxidative stress of the local environment. After tendon injury, oxidative stress is increased. Redox modulation might affect healing outcomes via affecting cellular activities in TDSCs. To study the effect of oxidative stress on TDSCs, the cellular activities of rat/human TDSCs were measured under different dosages of vitamin C or H2O2 in this study. Lower dose of vitamin C increased cell proliferation, viability and migration; H2O2 affected colony formation and suppressed cell migration, cell viability, apoptosis, and proliferation. Consistent with previous studies, oxidative stresses (H2O2 affect both recruitment and survival of TDSCs, while the antioxidant vitamin C may exert beneficial effects at low doses. In conclusion, redox modulation affected cellular activities of TDSCs and might be a potential strategy for tendon healing treatment.

  3. Rho GTPase activity modulates paramyxovirus fusion protein-mediated cell-cell fusion

    International Nuclear Information System (INIS)

    Schowalter, Rachel M.; Wurth, Mark A.; Aguilar, Hector C.; Lee, Benhur; Moncman, Carole L.; McCann, Richard O.; Dutch, Rebecca Ellis

    2006-01-01

    The paramyxovirus fusion protein (F) promotes fusion of the viral envelope with the plasma membrane of target cells as well as cell-cell fusion. The plasma membrane is closely associated with the actin cytoskeleton, but the role of actin dynamics in paramyxovirus F-mediated membrane fusion is unclear. We examined cell-cell fusion promoted by two different paramyxovirus F proteins in three cell types in the presence of constitutively active Rho family GTPases, major cellular coordinators of actin dynamics. Reporter gene and syncytia assays demonstrated that expression of either Rac1 V12 or Cdc42 V12 could increase cell-cell fusion promoted by the Hendra or SV5 glycoproteins, though the effect was dependent on the cell type expressing the viral glycoproteins. In contrast, RhoA L63 decreased cell-cell fusion promoted by Hendra glycoproteins but had little affect on SV5 F-mediated fusion. Also, data suggested that GTPase activation in the viral glycoprotein-containing cell was primarily responsible for changes in fusion. Additionally, we found that activated Cdc42 promoted nuclear rearrangement in syncytia

  4. Amphipaths Differentially Modulate Membrane Surface Deformation in Rat Peritoneal Mast Cells During Exocytosis

    Directory of Open Access Journals (Sweden)

    Itsuro Kazama

    2013-04-01

    Full Text Available Background/Aims: Salicylate and chlorpromazine exert differential effects on the chemokine release from mast cells. Since these drugs are amphiphilic and preferentially partitioned into the lipid bilayers of the plasma membranes, they would induce some morphological changes in mast cells and thus affect the process of exocytosis. Methods: Employing the standard patch-clamp whole-cell recording technique, we examined the effects of salicylate and chlorpromazine on the membrane capacitance (Cm during exocytosis in rat peritoneal mast cells. Using confocal imaging of a water-soluble fluorescent dye, lucifer yellow, we also examined their effects on plasma membrane deformation of the cells. Results: Salicylate dramatically accelerated the GTP-γ-S-induced increase in the Cm immediately after its application, whereas chlorpromazine significantly suppressed the increase. Treatment with salicylate increased the trapping of the dye on the cell surface, while treatment with chlorpromazine completely washed it out, indicating that both drugs induced membrane surface deformation in mast cells. Conclusion: This study demonstrated for the first time that membrane amphipaths, such as salicylate and chlorpromazine, may oppositely modulate the process of exocytosis in mast cells, as detected by the changes in the Cm. The plasma membrane deformation induced by the drugs was thought to be responsible for their differential effects.

  5. Effects of Epigenetic Modulation on Reporter Gene Expression: Implications for Stem Cell Imaging

    Science.gov (United States)

    Krishnan, Manickam; Park, Jinha M.; Cao, Feng; Wang, Dongxu; Paulmurugan, Ramasay; Tseng, Jeffrey R.; Gonzalgo, Mark L.; Gambhir, Sanjiv S.; Wu, Joseph C.

    2013-01-01

    Tracking stem cell localization, survival, differentiation, and proliferation following transplantation in living subjects is essential for understanding stem cell biology and physiology. In this study, we investigated the long-term stability of reporter gene expression in an embryonic rat cardiomyoblast cell line and the role of epigenetic modulation on reversing reporter gene silencing. Cells were stably transfected with plasmids carrying cytomegalovirus promoter driving firefly luciferase reporter gene (CMV-Fluc) and passaged repeatedly for 3–8 months. Within the highest expressor clone, the firefly luciferase activity decreased progressively from passage-1 (843±28) to passage-20 (250±10) to passage-40 (44±3) to passage-60 (3±1 RLU/µg) (P<0.05 vs. passage-1). Firefly luciferase activity was maximally rescued by treatment with 5-azacytidine (DNA methyltransferase inhibitor) compared to trichostatin A (histone deacetylase inhibitor) and retinoic acid (transcriptional activator) (P<0.05). Increasing dosages of 5-azacytidine treatment led to higher levels of firefly luciferase mRNA (RT-PCR) and protein (Western blots) and inversely lower levels of methylation in the CMV promoter (DNA nucleotide sequence). These in vitro results were extended to in vivo bioluminescence imaging (BLI) of cell transplant in living animals. Cells treated with 5-azacytidine were monitored for 2 weeks compared to 1 week for untreated cells (P<0.05). These findings should have important implications for reporter gene-based imaging of stem cell transplantation. PMID:16246867

  6. Selective Modulation of Integrin-mediated Cell Migration by Distinct ADAM Family MembersV⃞

    Science.gov (United States)

    Huang, Jing; Bridges, Lance C.; White, Judith M.

    2005-01-01

    A disintegrin and a metalloprotease (ADAM) family members have been implicated in many biological processes. Although it is recognized that recombinant ADAM disintegrin domains can interact with integrins, little is known about ADAM-integrin interactions in cellular context. Here, we tested whether ADAMs can selectively regulate integrin-mediated cell migration. ADAMs were expressed in Chinese hamster ovary cells that express defined integrins (α4β1, α5β1, or both), and cell migration on full-length fibronectin or on its α4β1 or α5β1 binding fragments was studied. We found that ADAMs inhibit integrin-mediated cell migration in patterns dictated by the integrin binding profiles of their isolated disintegrin domains. ADAM12 inhibited cell migration mediated by the α4β1 but not the α5β1 integrin. ADAM17 had the reciprocal effect; it inhibited α5β1- but not α4β1-mediated cell migration. ADAM19 and ADAM33 inhibited migration mediated by both α4β1 and α5β1 integrins. A point mutation in the ADAM12 disintegrin loop partially reduced the inhibitory effect of ADAM12 on cell migration on the α4β1 binding fragment of fibronectin, whereas mutations that block metalloprotease activity had no effect. Our results indicate that distinct ADAMs can modulate cell migration mediated by specific integrins in a pattern dictated, at least in part, by their disintegrin domains. PMID:16079176

  7. Phosphofructokinase-P Modulates P44/42 MAPK Levels in HeLa Cells.

    Science.gov (United States)

    Cardim Pires, Thyago Rubens; Albanese, Jamille Mansur; Schwab, Michael; Marette, André; Carvalho, Renato Sampaio; Sola-Penna, Mauro; Zancan, Patricia

    2017-05-01

    It is known that interfering with glycolysis leads to profound modification of cancer cell proliferation. However, energy production is not the major reason for this correlation. Here, using HeLa cells as a model for cancer, we demonstrate that phosphofructokinase-P (PFK-P), which is overexpressed in diverse types of cancer including HeLa cells, modulates expression of P44/42 mitogen-activated protein kinase (MAPK). Silencing of PFK-P did not alter HeLa cell viability or energy production, including the glycolytic rate. On the other hand, silencing of PFK-P induced the downregulation of p44/42 MAPK, augmenting the sensitivity of HeLa cells to different drugs. Conversely, overexpression of PFK-P promotes the upregulation of p44/42 MAPK, making the cells more resistant to the drugs. These results indicate that overexpression of PFK-P by cancer cells is related to activation of survival pathways via upregulation of MAPK and suggest PFK-P as a promising target for cancer therapy. J. Cell. Biochem. 118: 1216-1226, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  8. Mast Cell Subsets and Their Functional Modulation by the Acanthocheilonema viteae Product ES-62

    Directory of Open Access Journals (Sweden)

    Dimity H. Ball

    2013-01-01

    Full Text Available ES-62, an immunomodulator secreted by filarial nematodes, exhibits therapeutic potential in mouse models of allergic inflammation, at least in part by inducing the desensitisation of FcεRI-mediated mast cell responses. However, in addition to their pathogenic roles in allergic and autoimmune diseases, mast cells are important in fighting infection, wound healing, and resolving inflammation, reflecting that mast cells exhibit a phenotypic and functional plasticity. We have therefore characterised the differential functional responses to antigen (via FcεRI and LPS and their modulation by ES-62 of the mature peritoneal-derived mast cells (PDMC; serosal and those of the connective tissue-like mast cells (CTMC and the mucosal-like mast cells derived from bone marrow progenitors (BMMC as a first step to produce disease tissue-targeted therapeutics based on ES-62 action. All three mast cell populations were rendered hyporesponsive by ES-62 and whilst the mechanisms underlying such desensitisation have not been fully delineated, they reflect a downregulation of calcium and PKCα signalling. ES-62 also downregulated MyD88 and PKCδ in mucosal-type BMMC but not PDMC, the additional signals targeted in mucosal-type BMMC likely reflecting that these cells respond to antigen and LPS by degranulation and cytokine secretion whereas PDMC predominantly respond in a degranulation-based manner.

  9. Safety assessment of immunomodulatory biologics: the promise and challenges of regulatory T-cell modulation.

    Science.gov (United States)

    Ponce, Rafael A

    2011-01-01

    Regulatory T-cell (T(reg)) modulation is developing as an important therapeutic opportunity for the treatment of a number of important diseases, including cancer, autoimmunity, infection, and organ transplant rejection. However, as demonstrated with IL-2 and TGN-1412, our understanding of the complex immunological interactions that occur with T(reg) modulation in both non-clinical models and in patients remains limited and appears highly contextual. This lack of understanding will challenge our ability to identify the patient population who might derive the highest benefit from T(reg) modulation and creates special challenges as we transition these therapeutics from non-clinical models into humans. Thus, in vivo testing in the most representative animal model systems, with careful progress in the clinic, will remain critical in developing therapeutics targeting T(reg) and understanding their clinical utility. Moreover, toxicology models can inform some of the potential liabilities associated with T(reg) modulation, but not all, suggesting a continued need to explore and validate predictive models.

  10. Intracellular calcium modulation of voltage-gated sodium channels in ventricular myocytes

    NARCIS (Netherlands)

    Casini, Simona; Verkerk, Arie O.; van Borren, Marcel M. G. J.; van Ginneken, Antoni C. G.; Veldkamp, Marieke W.; de Bakker, Jacques M. T.; Tan, Hanno L.

    2009-01-01

    AIMS: Cardiac voltage-gated sodium channels control action potential (AP) upstroke and cell excitability. Intracellular calcium (Ca(i)(2+)) regulates AP properties by modulating various ion channels. Whether Ca(i)(2+) modulates sodium channels in ventricular myocytes, is unresolved. We studied

  11. Understanding the cell-to-module efficiency gap in Cu(In,Ga)(S,Se)2 photovoltaics scale-up

    Science.gov (United States)

    Bermudez, Veronica; Perez-Rodriguez, Alejandro

    2018-06-01

    Cu(In,Ga)(S,Se)2 (CIGS) solar cells show record efficiencies comparable to those of crystalline Si-based technologies. Their industrial module production costs are also comparable to those of Si photovoltaics in spite of their much lower production volume. However, the competitiveness of CIGS is compromised by the difference in performance between cell and module scales, known as the cell-to-module efficiency gap, which is significantly higher than in competing industrial photovoltaic technologies. In this Review, we quantify the main cell-to-module efficiency loss mechanisms and discuss the various strategies explored in academia and industry to reduce the efficiency gap: new transparent conductive oxides, hybrid modularization approaches and the use of wide-bandgap solar absorbers in the 1.4-1.5 eV range. To implement these strategies, research gaps relating to various device layers need to be filled.

  12. T-cell triggering thresholds are modulated by the number of antigen within individual T-cell receptor clusters

    Energy Technology Data Exchange (ETDEWEB)

    Manz, Boryana N. [Howard Hughes Medical Inst., Chevy Chase, MD (United States); Univ. of California, Berkeley, CA (United States); Jackson, Bryan L. [Howard Hughes Medical Inst., Chevy Chase, MD (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Petit, Rebecca S. [Howard Hughes Medical Inst., Chevy Chase, MD (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dustin, Michael L. [New York School of Medicine, New York, NY (United States); Groves, Jay [Howard Hughes Medical Inst., Chevy Chase, MD (United States); Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2011-05-31

    T cells react to extremely small numbers of activating agonist peptides. Spatial organization of T-cell receptors (TCR) and their peptide-major histocompatibility complex (pMHC) ligands into microclusters is correlated with T-cell activation. In this study, we have designed an experimental strategy that enables control over the number of agonist peptides per TCR cluster, without altering the total number engaged by the cell. Supported membranes, partitioned with grids of barriers to lateral mobility, provide an effective way of limiting the total number of pMHC ligands that may be assembled within a single TCR cluster. Observations directly reveal that restriction of pMHC content within individual TCR clusters can decrease T-cell sensitivity for triggering initial calcium flux at fixed total pMHC density. Further analysis suggests that triggering thresholds are determined by the number of activating ligands available to individual TCR clusters, not by the total number encountered by the cell. Results from a series of experiments in which the overall agonist density and the maximum number of agonist per TCR cluster are independently varied in primary T cells indicate that the most probable minimal triggering unit for calcium signaling is at least four pMHC in a single cluster for this system. In conclusion, this threshold is unchanged by inclusion of coagonist pMHC, but costimulation of CD28 by CD80 can modulate the threshold lower.

  13. Extra-virgin olive oil phenols block cell cycle progression and modulate chemotherapeutic toxicity in bladder cancer cells

    Science.gov (United States)

    Coccia, Andrea; Mosca, Luciana; Puca, Rosa; Mangino, Giorgio; Rossi, Alessandro; Lendaro, Eugenio

    2016-01-01

    Epidemiological data indicate that the daily consumption of extra-virgin olive oil (EVOO), a common dietary habit of the Mediterranean area, lowers the incidence of certain types of cancer, in particular bladder neoplasm. The aim of the present study was to evaluate the antiproliferative activity of polyphenols extracted from EVOO on bladder cancer (BCa), and to clarify the biological mechanisms that trigger cell death. Furthermore, we also evaluated the ability of low doses of extra-virgin olive oil extract (EVOOE) to modulate the in vitro activity of paclitaxel or mitomycin, two antineoplastic drugs used in the management of different types of cancer. Our results showed that EVOOE significantly inhibited the proliferation and clonogenic ability of T24 and 5637 BCa cells in a dose-dependent manner. Furthermore, cell cycle analysis after EVOOE treatment showed a marked growth arrest prior to mitosis in the G2/M phase for both cell lines, with the subsequent induction of apoptosis only in the T24 cells. Notably, simultaneous treatment of mitomycin C and EVOOE reduced the drug cytotoxicity due to inhibition of ROS production. Conversely, the co-treatment of T24 cells with paclitaxel and the polyphenol extract strongly increased the apoptotic cell death at each tested concentration compared to paclitaxel alone. Our results support the epidemiological evidence indicating that olive oil consumption exerts health benefits and may represent a starting point for the development of new anticancer strategies. PMID:27748855

  14. Zizyphin modulates calcium signalling in human taste bud cells and fat taste perception in the mouse.

    Science.gov (United States)

    Murtaza, Babar; Berrichi, Meryem; Bennamar, Chahid; Tordjmann, Thierry; Djeziri, Fatima Z; Hichami, Aziz; Leemput, Julia; Belarbi, Meriem; Ozdener, Hakan; Khan, Naim A

    2017-10-01

    Zizyphin, isolated from Zizyphus sps. leaf extracts, has been shown to modulate sugar taste perception, and the palatability of a sweet solution is increased by the addition of fatty acids. We, therefore, studied whether zizyphin also modulates fat taste perception. Zizyphin was purified from edible fruit of Zizyphus lotus L. Zizyphin-induced increases in [Ca 2+ ]i in human taste bud cells (hTBC). Zizyphin shared the endoplasmic reticulum Ca 2+ pool and also recruited, in part, Ca 2+ from extracellular environment via the opening of store-operated Ca 2+ channels. Zizyphin exerted additive actions on linoleic acid (LA)-induced increases in [Ca 2+ ]i in these cells, indicating that zizyphin does not exert its action via fatty acid receptors. However, zizyphin seemed to exert, at least in part, its action via bile acid receptor Takeda-G-protein-receptor-5 in hTBC. In behavioural tests, mice exhibited preference for both LA and zizyphin. Interestingly, zizyphin increased the preference for a solution containing-LA. This study is the first evidence of the modulation of fat taste perception by zizyphin at the cellular level in hTBC. Our study might be helpful for considering the synthesis of zizyphin analogues as 'taste modifiers' with a potential in the management of obesity and lipid-mediated disorders. © 2017 Société Française de Pharmacologie et de Thérapeutique.

  15. H-ferritin-regulated microRNAs modulate gene expression in K562 cells.

    Directory of Open Access Journals (Sweden)

    Flavia Biamonte

    Full Text Available In a previous study, we showed that the silencing of the heavy subunit (FHC offerritin, the central iron storage molecule in the cell, is accompanied by a modification in global gene expression. In this work, we explored whether different FHC amounts might modulate miRNA expression levels in K562 cells and studied the impact of miRNAs in gene expression profile modifications. To this aim, we performed a miRNA-mRNA integrative analysis in K562 silenced for FHC (K562shFHC comparing it with K562 transduced with scrambled RNA (K562shRNA. Four miRNAs, namely hsa-let-7g, hsa-let-7f, hsa-let-7i and hsa-miR-125b, were significantly up-regulated in silenced cells. The remarkable down-regulation of these miRNAs, following FHC expression rescue, supports a specific relation between FHC silencing and miRNA-modulation. The integration of target predictions with miRNA and gene expression profiles led to the identification of a regulatory network which includes the miRNAs up-regulated by FHC silencing, as well as91 down-regulated putative target genes. These genes were further classified in 9 networks; the highest scoring network, "Cell Death and Survival, Hematological System Development and Function, Hematopoiesis", is composed by 18 focus molecules including RAF1 and ERK1/2. We confirmed that, following FHC silencing, ERK1/2 phosphorylation is severely impaired and that RAF1 mRNA is significantly down-regulated. Taken all together, our data indicate that, in our experimental model, FHC silencing may affect RAF1/pERK1/2 levels through the modulation of a specific set of miRNAs and add new insights in to the relationship among iron homeostasis and miRNAs.

  16. Cell signaling heterogeneity is modulated by both cell-intrinsic and -extrinsic mechanisms: An integrated approach to understanding targeted therapy.

    Science.gov (United States)

    Kim, Eunjung; Kim, Jae-Young; Smith, Matthew A; Haura, Eric B; Anderson, Alexander R A

    2018-03-01

    During the last decade, our understanding of cancer cell signaling networks has significantly improved, leading to the development of various targeted therapies that have elicited profound but, unfortunately, short-lived responses. This is, in part, due to the fact that these targeted therapies ignore context and average out heterogeneity. Here, we present a mathematical framework that addresses the impact of signaling heterogeneity on targeted therapy outcomes. We employ a simplified oncogenic rat sarcoma (RAS)-driven mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase-protein kinase B (PI3K-AKT) signaling pathway in lung cancer as an experimental model system and develop a network model of the pathway. We measure how inhibition of the pathway modulates protein phosphorylation as well as cell viability under different microenvironmental conditions. Training the model on this data using Monte Carlo simulation results in a suite of in silico cells whose relative protein activities and cell viability match experimental observation. The calibrated model predicts distributional responses to kinase inhibitors and suggests drug resistance mechanisms that can be exploited in drug combination strategies. The suggested combination strategies are validated using in vitro experimental data. The validated in silico cells are further interrogated through an unsupervised clustering analysis and then integrated into a mathematical model of tumor growth in a homogeneous and resource-limited microenvironment. We assess posttreatment heterogeneity and predict vast differences across treatments with similar efficacy, further emphasizing that heterogeneity should modulate treatment strategies. The signaling model is also integrated into a hybrid cellular automata (HCA) model of tumor growth in a spatially heterogeneous microenvironment. As a proof of concept, we simulate tumor responses to targeted therapies in a spatially segregated tissue structure containing tumor

  17. Metabolic modulation induced by oestradiol and DHT in immature rat Sertoli cells cultured in vitro.

    Science.gov (United States)

    Rato, Luís; Alves, Marco G; Socorro, Sílvia; Carvalho, Rui A; Cavaco, José E; Oliveira, Pedro F

    2012-02-01

    Sertoli cells actively metabolize glucose that is converted into lactate, which is used by developing germ cells for their energy metabolism. Androgens and oestrogens have general metabolic roles that reach far beyond reproductive processes. Hence, the main purpose of this study was to examine the effect of sex hormones on metabolite secretion/consumption in primary cultures of rat Sertoli cells. Sertoli cell-enriched cultures were maintained in a defined medium for 50 h. Glucose and pyruvate consumption, and lactate and alanine secretion were determined, by 1H-NMR (proton NMR) spectra analysis, in the presence or absence of 100 nM E2 (17β-oestradiol) or 100 nM 5α-DHT (dihydrotestosterone). Cells cultured in the absence (control) or presence of E2 consumed the same amount of glucose (29±2 pmol/cell) at similar rates during the 50 h. After 25 h of treatment with DHT, glucose consumption and glucose consumption rate significantly increased. Control and E2-treated cells secreted similar amounts of lactate during the 50 h, while the amount of lactate secreted by DHT-treated cells was significantly lower. Such a decrease was concomitant with a significant decrease in LDH A [LDH (lactate dehydrogenase) chain A] and MCT4 [MCT (monocarboxylate transporter) isoform 4] mRNA levels after 50 h treatment in hormonally treated groups, being more pronounced in DHT-treated groups. Finally, alanine production was significantly increased in E2-treated cells after 25 h treatment, which indicated a lower redox/higher oxidative state for the cells in those conditions. Together, these results support the existence of a relation between sex hormones action and energy metabolism, providing an important assessment of androgens and oestrogens as metabolic modulators in rat Sertoli cells.

  18. Modulation of SOCS protein expression influences the interferon responsiveness of human melanoma cells

    International Nuclear Information System (INIS)

    Lesinski, Gregory B; Zimmerer, Jason M; Kreiner, Melanie; Trefry, John; Bill, Matthew A; Young, Gregory S; Becknell, Brian; Carson, William E III

    2010-01-01

    Endogenously produced interferons can regulate the growth of melanoma cells and are administered exogenously as therapeutic agents to patients with advanced cancer. We investigated the role of negative regulators of interferon signaling known as suppressors of cytokine signaling (SOCS) in mediating interferon-resistance in human melanoma cells. Basal and interferon-alpha (IFN-α) or interferon-gamma (IFN-γ)-induced expression of SOCS1 and SOCS3 proteins was evaluated by immunoblot analysis in a panel of n = 10 metastatic human melanoma cell lines, in human embryonic melanocytes (HEM), and radial or vertical growth phase melanoma cells. Over-expression of SOCS1 and SOCS3 proteins in melanoma cells was achieved using the PINCO retroviral vector, while siRNA were used to inhibit SOCS1 and SOCS3 expression. Tyr 701 -phosphorylated STAT1 (P-STAT1) was measured by intracellular flow cytometry and IFN-stimulated gene expression was measured by Real Time PCR. SOCS1 and SOCS3 proteins were expressed at basal levels in melanocytes and in all melanoma cell lines examined. Expression of the SOCS1 and SOCS3 proteins was also enhanced following stimulation of a subset of cell lines with IFN-α or IFN-γ. Over-expression of SOCS proteins in melanoma cell lines led to significant inhibition of Tyr 701 -phosphorylated STAT1 (P-STAT1) and gene expression following stimulation with IFN-α (IFIT2, OAS-1, ISG-15) or IFN-γ (IRF1). Conversely, siRNA inhibition of SOCS1 and SOCS3 expression in melanoma cells enhanced their responsiveness to interferon stimulation. These data demonstrate that SOCS proteins are expressed in human melanoma cell lines and their modulation can influence the responsiveness of melanoma cells to IFN-α and IFN-γ

  19. Development of measurement device for evaluation of solar cell module output. 2; Taiyo denchi module shutsuryoku hyokayo sokuteiki no kaihatsu. 2

    Energy Technology Data Exchange (ETDEWEB)

    Minoda, M.; Itsumi, J. [Kumamoto Institute of Technology, Kumamoto (Japan)

    1996-10-27

    Enhancement in design efficiency may be attained as well as utilization in maintenance if on-the-spot data is made available, for the purpose of flexibly dealing with changes in design or matching with a house structure, in calculating the power generation output of a solar cell (PV) module. Under the circumstances, a small-sized compound measuring device was produced as a prototype which, using an I-V curve tracer, measured output and condition of a roof at the time of installation, compared with the optimum operation and predicted the power generation. The device was structured with the main body consisting of a computing part, measurement controller and power supply and with various sensor modules. The electron load control method was employed in order to measure I-V characteristics of the PV module, since it was desirable to use a variable load and to cover the range from the release voltage of a solar cell to the short-circuit state through the maximum output point. The reference module method was used for the system evaluation. The device was presumably applicable to a PV system design by incorporating a sensor module for measuring design environment data, which was essential at the time of a system design, in addition to those for measuring output. 9 refs., 4 figs., 3 tabs.

  20. Senescence-Induced Alterations of Laminin Chain Expression Modulate Tumorigenicity of Prostate Cancer Cells1

    Science.gov (United States)

    Sprenger, Cynthia C T; Drivdahl, Rolf H; Woodke, Lillie B; Eyman, Daniel; Reed, May J; Carter, William G; Plymate, Stephen R

    2008-01-01

    Prostate cancer is an age-associated epithelial cancer, and as such, it contributes significantly to the mortality of the elderly. Senescence is one possible mechanism by which the body defends itself against various epithelial cancers. Senescent cells alter the microenvironment, in part, through changes to the extracellular matrix. Laminins (LMs) are extracellular proteins important to both the structure and function of the microenvironment. Overexpression of the senescence-associated gene mac25 in human prostate cancer cells resulted in increased mRNA levels of the LM α4 and β2 chains compared to empty vector control cells. The purpose of this study was to examine the effects of these senescence-induced LM chains on tumorigenicity of prostate cancer cells. We created stable M12 human prostate cancer lines overexpressing either the LM α4 or β2 chain or both chains. Increased expression of either the LM α4 or β2 chain resulted in increased in vitro migration and in vivo tumorigenicity of those cells, whereas high expression of both chains led to decreased in vitro proliferation and in vivo tumorigenicity compared to M12 control cells. This study demonstrates that senescent prostate epithelial cells can alter the microenvironment and that these changes modulate progression of prostate cancer. PMID:19048114

  1. Senescence-Induced Alterations of Laminin Chain Expression Modulate Tumorigenicity of Prostate Cancer Cells

    Directory of Open Access Journals (Sweden)

    Cynthia C.T. Sprenger

    2008-12-01

    Full Text Available Prostate cancer is an age-associated epithelial cancer, and as such, it contributes significantly to the mortality of the elderly. Senescence is one possible mechanism by which the body defends itself against various epithelial cancers. Senescent cells alter the microenvironment, in part, through changes to the extracellular matrix. Laminins (LMs are extracellular proteins important to both the structure and function of the microenvironment. Overexpression of the senescence-associated gene mac25 in human prostate cancer cells resulted in increased mRNA levels of the LM α4 and β2 chains compared to empty vector control cells. The purpose of this study was to examine the effects of these senescence-induced LM chains on tumorigenicity of prostate cancer cells. We created stable M12 human prostate cancer lines overexpressing either the LM α4 or β2 chain or both chains. Increased expression of either the LM α4 or β2 chain resulted in increased in vitro migration and in vivo tumorigenicity of those cells, whereas high expression of both chains led to decreased in vitro proliferation and in vivo tumorigenicity compared to M12 control cells. This study demonstrates that senescent prostate epithelial cells can alter the microenvironment and that these changes modulate progression of prostate cancer.

  2. Controlling Gel Structure to Modulate Cell Adhesion and Spreading on the Surface of Microcapsules.

    Science.gov (United States)

    Zheng, Huizhen; Gao, Meng; Ren, Ying; Lou, Ruyun; Xie, Hongguo; Yu, Weiting; Liu, Xiudong; Ma, Xiaojun

    2016-08-03

    The surface properties of implanted materials or devices play critical roles in modulating cell behavior. However, the surface properties usually affect cell behaviors synergetically so that it is still difficult to separately investigate the influ