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Sample records for plateau phase cells

  1. Inhibition of B-NHEJ in Plateau-Phase Cells Is Not a Direct Consequence of Suppressed Growth Factor Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Satyendra K.; Bednar, Theresa; Zhang Lihua [Institute of Medical Radiation Biology, University Duisburg-Essen Medical School, Essen (Germany); Wu, Wenqi [First Affiliated Hospital of Guangzhou, Urology Department, Minimally Invasive Center, Medical College, 510230 Guangzhou (China); Mladenov, Emil [Institute of Medical Radiation Biology, University Duisburg-Essen Medical School, Essen (Germany); Iliakis, George, E-mail: Georg.Iliakis@uk-essen.de [Institute of Medical Radiation Biology, University Duisburg-Essen Medical School, Essen (Germany)

    2012-10-01

    Purpose: It has long been known that the proliferation status of a cell is a determinant of radiation response, and the available evidence implicates repair of DNA double-strand breaks (DSBs) in the underlying mechanism. Recent results have shown that a novel, highly error-prone pathway of nonhomologous end joining (NHEJ) operating as backup (B-NHEJ) processes DSBs in irradiated cells when the canonical, DNA-PK (DNA-dependent protein kinase)-dependent pathway of NHEJ (D-NHEJ) is compromised. Notably, B-NHEJ shows marked reduction in efficiency when D-NHEJ-deficient cells cease to grow and enter a plateau phase. This phenomenon is widespread and observed in cells of different species with defects in core components of D-NHEJ, with the notable exception of DNA-PKcs (DNA-dependent protein kinase, catalytic subunit). Using new, standardized serum-deprivation protocols, we re-examine the growth requirements of B-NHEJ and test the role of epidermal growth factor receptor (EGFR) signaling in its regulation. Methods and Materials: DSB repair was measured by pulsed-field gel electrophoresis in cells maintained under different conditions of growth. Results: Serum deprivation in D-NHEJ-deficient cells causes a rapid reduction in B-NHEJ similar to that measured in normally growing cells that enter the plateau phase of growth. Upon serum deprivation, reduction in B-NHEJ activity is evident at 4 h and reaches a plateau reflecting maximum inhibition at 12-16 h. The inhibition is reversible, and B-NHEJ quickly recovers to the levels of actively growing cells upon supply of serum to serum-deprived cells. Chemical inhibition of EGFR in proliferating cells inhibits only marginally B-NHEJ and addition of EGFR in serum-deprived cells increases only a marginally B-NHEJ. Conclusions: The results document a rapid and fully reversible adaptation of B-NHEJ to growth activity and point to factors beyond EGFR in its regulation. They show notable differences in the regulation of error

  2. Interaction between x-irradiated plateau-phase bone marrow stromal cell lines and co-cultivated factor-dependent cell lines leading to leukemogenesis in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Naparstek, E.; Anklesaria, P.; FitzGerald, T.J.; Sakakeeny, M.A.; Greenberger, J.S.

    1987-03-01

    Plateau-phase mouse clonal bone marrow stromal cell lines D2XRII and C3H cl 11 produce decreasing levels of M-CSF (CSF-1), a specific macrophage progenitor cell humoral regulator, following X-irradiation in vitro. The decrease did not go below 40% of control levels, even after irradiation doses of 50,000 rad (500 Gy). In contrast, a distinct humoral regulator stimulating growth of GM-CSF/IL-3 factor-dependent (FD) hematopoietic progenitor cell lines was detected following radiation to doses above 2000 rad. This humoral factor was not detectable in conditioned medium from irradiated cells, weakly detected using factor-dependent target cell populations in agar overlay, and was prominently detected by liquid co-cultivation of factor-dependent cells with irradiated stromal cell cultures. Subclonal lines of FD cells, derived after co-cultivation revealed karyotypic abnormalities and induced myeloblastic tumors in syngeneic mice. Five-eight weeks co-cultivation was required for induction of factor independence and malignancy and was associated with dense cell to cell contact between FD cells and stromal cells demonstrated by light and electron microscopy. Increases in hematopoietic to stromal cell surface area, total number of adherent cells per flask, total non-adherent cell colonies per flask, and cumulative non-adherent cell production were observed after irradiation. The present data may prove very relevant to an understanding of the cell to cell interactions during X-irradiation-induced leukemia.

  3. Dual pathways of calcium entry in spike and plateau phases of luteinizing hormone release from chicken pituitary cells: sequential activation of receptor-operated and voltage-sensitive calcium channels by gonadotropin-releasing hormone

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, J.S.; Wakefield, I.K.; King, J.A.; Mulligan, G.P.; Millar, R.P.

    1988-04-01

    It has previously been shown that, in pituitary gonadotrope cells, the initial rise in cytosolic Ca2+ induced by GnRH is due to a Ca2+ mobilization from intracellular stores. This raises the possibility that the initial transient spike phase of LH release might be fully or partially independent of extracellular Ca2+. We have therefore characterized the extracellular Ca2+ requirements, and the sensitivity to Ca2+ channel blockers, of the spike and plateau phases of secretion separately. In the absence of extracellular Ca2+ the spike and plateau phases were inhibited by 65 +/- 4% and 106 +/- 3%, respectively. Both phases exhibited a similar dependence on concentration of extracellular Ca2+. However, voltage-sensitive Ca2+ channel blockers D600 and nifedipine had a negligible effect on the spike phase, while inhibiting the plateau phase by approximately 50%. In contrast, ruthenium red, Gd3+ ions, and Co2+ ions inhibited both spike and plateau phases to a similar extent as removal of extracellular Ca2+. A fraction (35 +/- 4%) of spike phase release was resistant to removal of extracellular Ca2+. This fraction was abolished after calcium depletion of the cells by preincubation with EGTA in the presence of calcium ionophore A23187, indicating that it depends on intracellular Ca2+ stores. Neither absence of extracellular Ca2+, nor the presence of ruthenium red or Gd3+ prevented mobilization of 45Ca2+ from intracellular stores by GnRH. We conclude that mobilization of intracellular stored Ca2+ is insufficient by itself to account for full spike phase LH release.

  4. One-Third Magnetization Plateau with a Preceding Novel Phase in Volborthite

    Science.gov (United States)

    Ishikawa, H.; Yoshida, M.; Nawa, K.; Jeong, M.; Krämer, S.; Horvatić, M.; Berthier, C.; Takigawa, M.; Akaki, M.; Miyake, A.; Tokunaga, M.; Kindo, K.; Yamaura, J.; Okamoto, Y.; Hiroi, Z.

    2015-06-01

    We have synthesized high-quality single crystals of volborthite, a seemingly distorted kagome antiferromagnet, and carried out high-field magnetization measurements up to 74 T and V 51 NMR measurements up to 30 T. An extremely wide 1 /3 magnetization plateau appears above 28 T and continues over 74 T at 1.4 K, which has not been observed in previous studies using polycrystalline samples. NMR spectra reveal an incommensurate order (most likely a spin-density wave order) below 22 T and a simple spin structure in the plateau phase. Moreover, a novel intermediate phase is found between 23 and 26 T, where the magnetization varies linearly with magnetic field and the NMR spectra indicate an inhomogeneous distribution of the internal magnetic field. This sequence of phases in volborthite bears a striking similarity to those of frustrated spin chains with a ferromagnetic nearest-neighbor coupling J1 competing with an antiferromagnetic next-nearest-neighbor coupling J2 .

  5. Very early multi-color observations of the plateau phase of GRB 041006 afterglow

    CERN Document Server

    Urata, Y; Qiu, Y L; Hu, J; Kuo, P H; Tamagawa, T; Ip, W H; Kinoshita, D; Fukushi, H; Isogai, M; Miyata, T; Nakada, Y; Aoki, T; Soyano, T; Tarusawa, K; Mito, H; Onda, K; Ibrahimov, M; Pozanenko, A; Makishima, K

    2006-01-01

    Observations of the optical afterglow of GRB 041006 with the Kiso Observatory 1.05 m Schmidt telescope, the Lulin Observatory 1.0 m telescope and the Xinglong Observatory 0.6 m telescope. Three-bands (B, V and R) of photometric data points were obtained on 2004 October 6, 0.025-0.329 days after the burst. These very early multi band light curves imply the existence of a color dependent plateau phase. The B-band light curve shows a clear plateau at around 0.03 days after the burst. The R band light curve shows the hint of a plateau, or a possible slope change, at around 0.1 days after the burst. The overall behavior of these multi-band light curves may be interpreted in terms of the sum of two separate components, one showing a monotonic decay the other exhibiting a rising and a falling phase, as described by the standard afterglow model.

  6. A study of gamma ray bursts with afterglow plateau phases associated with supernovae

    Science.gov (United States)

    Dainotti, M. G.; Nagataki, S.; Maeda, K.; Postnikov, S.; Pian, E.

    2017-04-01

    Context. The analysis of 176 gamma ray burst (GRB) afterglow plateaus observed by Swift from GRBs with known redshifts revealed that the subsample of long GRBs associated with supernovae (LONG-SNe), comprising 19 events, presents a very high correlation coefficient between the luminosity at the end of the plateau phase LX(Ta) = La and the end time of the plateau . Furthermore, these SNe Ib/c associated with GRBs also obey the peak-magnitude stretch relation, which is similar to that used to standardize the SNe Ia. Aims: Our aim is to investigate a category of GRBs with plateau and associated with SNe to compare our correlation for this sample with the correlation for long GRBs for which no associated SN has been observed (hereafter LONG-NO-SNe, 128 GRBs) and to check whether there is a difference among these subsamples. Methods: We first adopted a nonparametric statistical method to take redshift evolution into account and to check if and how this effect may steepen the slope for the LONG-NO-SNe sample. This procedure is necessary because this sample is observed at much higher redshift than the GRB-SNe sample. Therefore, removing selection bias is the first step before any comparison among samples observed at different redshifts could be properly performed. Then, we applied the T-student test to evaluate a statistical difference between the slopes of the two samples. Results: We demonstrate that there is no evolution for the slope of the LONG-NO-SNe sample and no evolution is expected for GRBs observed at small redshifts such as those present in the LONG-SNe sample. The difference between the slope of the LONG-NO-SNe and the slope of LONG-SNe, i.e., those with firm spectral detection of SN components, is statistically significant (P = 0.005). Conclusions: This possibly suggests that, unlike LONG-NO-SNe, LONG-SNe with firm spectroscopic features of the associated SNe might not require a standard energy reservoir in the plateau phase. Therefore, this analysis may

  7. The Supercritical Pile Gamma-Ray Burst Model: The GRB Afterglow Steep Decline and Plateau Phase

    Science.gov (United States)

    Sultana, Joseph; Kazanas, D.; Mastichiadis, A.

    2013-01-01

    We present a process that accounts for the steep decline and plateau phase of the Swift X-Ray Telescope (XRT) light curves, vexing features of gamma-ray burst (GRB) phenomenology. This process is an integral part of the "supercritical pile" GRB model, proposed a few years ago to account for the conversion of the GRB kinetic energy into radiation with a spectral peak at E(sub pk) is approx. m(sub e)C(exp 2). We compute the evolution of the relativistic blast wave (RBW) Lorentz factor Gamma to show that the radiation-reaction force due to the GRB emission can produce an abrupt, small (approx. 25%) decrease in Gamma at a radius that is smaller (depending on conditions) than the deceleration radius R(sub D). Because of this reduction, the kinematic criticality criterion of the "supercritical pile" is no longer fulfilled. Transfer of the proton energy into electrons ceases and the GRB enters abruptly the afterglow phase at a luminosity smaller by approx. m(sub p)/m(sub e) than that of the prompt emission. If the radius at which this slow-down occurs is significantly smaller than R(sub D), the RBW internal energy continues to drive the RBW expansion at a constant (new) Gamma and its X-ray luminosity remains constant until R(sub D) is reached, at which point it resumes its more conventional decay, thereby completing the "unexpected" XRT light curve phase. If this transition occurs at R is approx. equal to R(sub D), the steep decline is followed by a flux decrease instead of a "plateau," consistent with the conventional afterglow declines. Besides providing an account of these peculiarities, the model suggests that the afterglow phase may in fact begin before the RBW reaches R is approx. equal to R(sub D), thus providing novel insights into GRB phenomenology.

  8. The supercritical pile gamma-ray burst model: The GRB afterglow steep decline and plateau phase

    Energy Technology Data Exchange (ETDEWEB)

    Sultana, J. [Mathematics Department, Faculty of Science, University of Malta, Msida MSD2080 (Malta); Kazanas, D. [Astrophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Mastichiadis, A., E-mail: joseph.sultana@um.edu.mt [Department of Physics, University of Athens, Panepistimiopolis, GR 15783 Zografos (Greece)

    2013-12-10

    We present a process that accounts for the steep decline and plateau phase of the Swift X-Ray Telescope (XRT) light curves, vexing features of gamma-ray burst (GRB) phenomenology. This process is an integral part of the 'supercritical pile' GRB model, proposed a few years ago to account for the conversion of the GRB kinetic energy into radiation with a spectral peak at E {sub pk} ∼ m{sub e}c {sup 2}. We compute the evolution of the relativistic blast wave (RBW) Lorentz factor Γ to show that the radiation-reaction force due to the GRB emission can produce an abrupt, small (∼25%) decrease in Γ at a radius that is smaller (depending on conditions) than the deceleration radius R{sub D} . Because of this reduction, the kinematic criticality criterion of the 'supercritical pile' is no longer fulfilled. Transfer of the proton energy into electrons ceases and the GRB enters abruptly the afterglow phase at a luminosity smaller by ∼m{sub p} /m{sub e} than that of the prompt emission. If the radius at which this slow-down occurs is significantly smaller than R{sub D} , the RBW internal energy continues to drive the RBW expansion at a constant (new) Γ and its X-ray luminosity remains constant until R{sub D} is reached, at which point it resumes its more conventional decay, thereby completing the 'unexpected' XRT light curve phase. If this transition occurs at R ≅ R{sub D} , the steep decline is followed by a flux decrease instead of a 'plateau,' consistent with the conventional afterglow declines. Besides providing an account of these peculiarities, the model suggests that the afterglow phase may in fact begin before the RBW reaches R ≅ R{sub D} , thus providing novel insights into GRB phenomenology.

  9. Love wave phase velocity models of the southeastern margin of Tibetan Plateau from a dense seismic array

    Science.gov (United States)

    Han, Fengqin; Jia, Ruizhi; Fu, Yuanyuan V.

    2017-08-01

    Love wave dispersion maps across the southeastern margin of the Tibetan Plateau are obtained using earthquake data recorded by the temporary ChinArray and permanent China Digital Seismic Array. Fundamental mode Love wave phase velocity curves are measured by inverting Love wave amplitude and phase with the two-plane-wave method. The phase velocity maps with resolution better than 150 km are presented at periods of 20-100 s, which is unprecedented in the study area. The maps agree well with each other and show clear correlations with major tectonic structures. The Love wave phase velocity could provide new information about structures in the crust and upper mantle beneath the southeast margin of Tibetan Plateau, like the radial anisotropy.

  10. Precipitation phase separation schemes in the Naqu River basin, eastern Tibetan plateau

    Science.gov (United States)

    Liu, Shaohua; Yan, Denghua; Qin, Tianling; Weng, Baisha; Lu, Yajing; Dong, Guoqiang; Gong, Boya

    2016-11-01

    Precipitation phase has a profound influence on the hydrological processes in the Naqu River basin, eastern Tibetan plateau. However, there are only six meteorological stations with precipitation phase (rainfall/snowfall/sleet) before 1979 within and around the basin. In order to separate snowfall from precipitation, a new separation scheme with S-shaped curve of snowfall proportion as an exponential function of daily mean temperature was developed. The determinations of critical temperatures in the single/two temperature threshold (STT/TTT2) methods were explored accordingly, and the temperature corresponding to the 50 % snowfall proportion (SP50 temperature) is an efficiently critical temperature for the STT, and two critical temperatures in TTT2 can be determined based on the exponential function and SP50 temperature. Then, different separation schemes were evaluated in separating snowfall from precipitation in the Naqu River basin. The results show that the S-shaped curve methods outperform other separation schemes. Although the STT and TTT2 slightly underestimate and overestimate the snowfall when the temperature is higher and colder than SP50 temperature respectively, the monthly and annual separation snowfalls are generally consistent with the observed snowfalls. On the whole, S-shaped curve methods, STT, and TTT2 perform well in separating snowfall from precipitation with the Pearson correlation coefficient of annual separation snowfall above 0.8 and provide possible approaches to separate the snowfall from precipitation for hydrological modelling.

  11. Characters of the Plateau of Methanol Increment in Frontal Analysis in Reversed Phase Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    GENG,Xin-Du(耿信笃); REGNIER,Fred E(弗莱德 依 瑞格涅尔)

    2002-01-01

    With insulin methanol-water, and the ion-pairing agent, hydrochloric acid and trifiuroacetic acid (TFA), the character of the first plateau (FP) on the elution curve of frontal analysis in reversed phase liquid chromatography (RPLC) was investigated by on-line UV-spectrometry and identified with nuclear magnetic resonance (NMR) spectrometry and mass spectrometry.The proffie of the FP is the same as that of a usual elution curve of methanol in frontal analysis (FA). When the insulin concentration was limited to a certain range, the height of the FP was found to be proportional to the insulin concentration in mobile phase and its length companying to shorten. The FP profile on the intersection of two tangents reflects the components of the microstructure in the depth direction of the bonded stationary phase layer and the desorption dynamics of the displaced components. The displaced methanol was quantitatively determined by NMR and on-line UV spectrometries. TFA with high UV absorbance can not be used as on ionpairing agent for the investigation of the FP in RPLC, but it can be used as a good marker to investigate the complicated transfer process of components in the stationary pdase in RPLC. A stoichiometric displacement process between solute and solvent was proved to be valid in both usual and FA in RPLC. From the point of view of dynamics of mass transfer,the solutes can only contact to the surface of stationary phase in usual RPLC, while solute can penetrate into it in FA of RPLC.The solvation of insulin in methanol and water solution as an example indicating the usage of the FP in the FA was also investigated in this paper.

  12. Effect of Handling, Storage and Cycling on Ni-H2 Cells: Second Plateau Phenomenon

    Science.gov (United States)

    Vaidyanathan, Hari; Rao, Gopalakrishna

    2001-01-01

    Proper handling of Ni-H2 cells/batteries in storage, during I&T, and at launch site is very important to preserve the useful energy and to extend the mission life. Cell reversal test is not a prudent test to verify or quantify the nickel pre-charge in Ni-H2 cells/batteries. The second plateau is due to the formation of Ni(+3) that is electrochemically inactive. Gas analysis of the cell, and chemical analysis of the positive plate are confirmatory tests to determine the nature of pre-charge in Ni-H2 cells.

  13. Comparison of time/phase lags in the hard state and plateau state of GRS 1915+105

    CERN Document Server

    Pahari, Mayukh; Yadav, J S; Misra, Ranjeev; Uttley, Phil

    2013-01-01

    We investigate the complex behavior of energy- and frequency-dependent time/phase lags in the plateau state and the radio-quiet hard state of GRS 1915+105. In our timing analysis, we find that when the source is faint in the radio, QPOs are observed above 2 Hz and typically exhibit soft lags (soft photons lag hard photons), whereas QPOs in the radio-bright plateau state are found below 2.2 Hz and consistently show hard lags. The phase lag at the QPO frequency is strongly anti-correlated with the QPO frequency, changing sign at 2.2 Hz. However, the phase lag at the frequency of the first harmonic is positive and nearly independent of frequency at at ~0.172 rad, regardless of the radio emission. The lag-energy dependence at the first harmonic is also independent of radio flux. However, the lags at the QPO frequency are negative at all energies during the radio-quiet state, but lags at the QPO frequency during the plateau state are positive at all energies and show a 'reflection-type' evolution of the lag-energy...

  14. Effect of Hypoxia on Ldh-c Expression in Somatic Cells of Plateau Pika.

    Science.gov (United States)

    Wei, Dengbang; Wei, Linna; Li, Xiao; Wang, Yang; Wei, Lian

    2016-08-01

    Sperm specific lactate dehydrogenases (LDH-C₄) is a lactate dehydrogenase that catalyzes the conversion of pyruvate to lactate. In mammals, Ldh-c was originally thought to be expressed only in testes and spermatozoa. Plateau pika (Ochotona curzoniae), which belongs to the genus Ochotona of the Ochotonidea family, is a hypoxia-tolerant mammal living 3000-5000 m above sea level on the Qinghai-Tibet Plateau, an environment which is strongly hypoxic. Ldh-c is expressed not only in testes and sperm, but also in the somatic tissues of plateau pika. To reveal the effect of hypoxia on pika Ldh-c expression, we investigated the mRNA and protein level of Ldh-c as well as the biochemical index of anaerobic glycolysis in pika somatic tissues at the altitudes of 2200 m, 3200 m and 3900 m. Our results showed that mRNA and protein expression levels of Ldh-c in the tissues of pika's heart, liver, brain and skeletal muscle were increased significantly from 2200 m to 3200 m, but had no difference from 3200 m to 3900 m; the activities of LDH and the contents of lactate showed no difference from 2200 m to 3200 m, but were increased significantly from 3200 m to 3900 m. Hypoxia up-regulated and maintained the expression levels of Ldh-c in the pika somatic cells. Under the hypoxia condition, plateau pikas increased anaerobic glycolysis in somatic cells by LDH-C₄, and that may have reduced their dependence on oxygen and enhanced their adaptation to the hypoxic environment.

  15. Novel phases in a square-lattice frustrated ferromagnet : 1/3 -magnetization plateau, helicoidal spin liquid, and vortex crystal

    Science.gov (United States)

    Seabra, Luis; Sindzingre, Philippe; Momoi, Tsutomu; Shannon, Nic

    2016-02-01

    A large part of the interest in magnets with frustrated antiferromagnetic interactions comes from the many new phases found in applied magnetic field. In this article, we explore some of the new phases which arise in a model with frustrated ferromagnetic interactions, the J1-J2-J3 Heisenberg model on a square lattice. Using a combination of classical Monte Carlo simulation and spin-wave theory, we uncover behavior reminiscent of some widely studied frustrated antiferromagnets, but with a number of new twists. We first demonstrate that, for a suitable choice of parameters, the phase diagram as a function of magnetic field and temperature is nearly identical to that of the Heisenberg antiferromagnet on a triangular lattice, including the celebrated 1 /3 -magnetization plateau. We then examine how this phase diagram changes when the model is tuned to a point where the classical ground state is highly degenerate. In this case, two new phases emerge: a classical, finite-temperature spin liquid, characterized by a "ring" in the spin structure factor S (q ) ; and a vortex crystal, a multiple-Q state with finite magnetization, which can be viewed as an ordered lattice of magnetic vortices. All of these new phases persist for a wide range of magnetic fields. We discuss the relationship between these results and published studies of frustrated antiferromagnets, together with some of the materials where these new phases might be observed in experiment.

  16. Gas-Phase Treatment of Technetium in the Vadose Zone at the Hanford Site Central Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Truex, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Szecsody, James E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhong, Lirong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Qafoku, Nikolla [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-09-01

    Technetium-99 (Tc-99) is present in the vadose zone of the Hanford Central Plateau and is a concern with respect to the protection of groundwater. The persistence, limited natural attenuation mechanisms, and geochemical behavior of Tc-99 in oxic vadose zone environments must be considered in developing effective alternatives for remediation. This report describes a new in situ geochemical manipulation technique for decreasing Tc-99 mobility using a combination of geochemical Tc-99 reduction with hydrogen sulfide gas and induced sediment mineral dissolution with ammonia vapor, which create conditions for deposition of stable precipitates that decrease the mobility of Tc-99. Laboratory experiments were conducted to examine changes in Tc-99 mobility in vadose zone sediment samples to evaluate the effectiveness of the treatment under a variety of operational and sediment conditions.

  17. High-Resolution Regional Phase Attenuation Models of the Iranian Plateau and Surrounding Regions

    Science.gov (United States)

    2014-03-03

    Mayeda, W. R. Walter, L. Malagnini, and W. S. Phillips, Regional Attenuation in Northern California: A Comparison of Five 1D Q Methods, Bull. Seism ...regional phase amplitude tomography, Seism . Res. Lett., 80, p. 360, 2009. Approved for public release; distribution is unlimited. 49 Priestley, K

  18. Monte Carlo study of half-magnetization plateau and magnetic phase diagram in pyrochlore antiferromagnetic Heisenberg model

    OpenAIRE

    Motome, Yukitoshi; Penc, Karlo; Shannon, Nic

    2005-01-01

    The antiferromagnetic Heisenberg model on a pyrochlore lattice under external magnetic field is studied by classical Monte Carlo simulation. The model includes bilinear and biquadratic interactions; the latter effectively describes the coupling to lattice distortions. The magnetization process shows a half-magnetization plateau at low temperatures, accompanied with strong suppression of the magnetic susceptibility. Temperature dependence of the plateau behavior is clarified. Finite-temperatur...

  19. Effect of Hypoxia on Ldh-c Expression in Somatic Cells of Plateau Pika

    OpenAIRE

    Wei, Dengbang; Wei, Linna; Li, Xiao; Wang, Yang; Wei, Lian

    2016-01-01

    Sperm specific lactate dehydrogenases (LDH-C4) is a lactate dehydrogenase that catalyzes the conversion of pyruvate to lactate. In mammals, Ldh-c was originally thought to be expressed only in testes and spermatozoa. Plateau pika (Ochotona curzoniae), which belongs to the genus Ochotona of the Ochotonidea family, is a hypoxia-tolerant mammal living 3000–5000 m above sea level on the Qinghai-Tibet Plateau, an environment which is strongly hypoxic. Ldh-c is expressed not only in testes and sper...

  20. Spiny Neurons of Amygdala, Striatum and Cortex Use Dendritic Plateau Potentials to Detect Network UP States

    Directory of Open Access Journals (Sweden)

    Katerina D Oikonomou

    2014-09-01

    Full Text Available Spiny neurons of amygdala, striatum, and cerebral cortex share four interesting features: [1] they are the most abundant cell type within their respective brain area, [2] covered by thousands of thorny protrusions (dendritic spines, [3] possess high levels of dendritic NMDA conductances, and [4] experience sustained somatic depolarizations in vivo and in vitro (UP states. In all spiny neurons of the forebrain, adequate glutamatergic inputs generate dendritic plateau potentials (dendritic UP states characterized by (i fast rise, (ii plateau phase lasting several hundred milliseconds and (iii abrupt decline at the end of the plateau phase. The dendritic plateau potential propagates towards the cell body decrementally to induce a long-lasting (longer than 100 ms, most often 200 – 800 ms steady depolarization (~20 mV amplitude, which resembles a neuronal UP state. Based on voltage-sensitive dye imaging, the plateau depolarization in the soma is precisely time-locked to the regenerative plateau potential taking place in the dendrite. The somatic plateau rises after the onset of the dendritic voltage transient and collapses with the breakdown of the dendritic plateau depolarization. We hypothesize that neuronal UP states in vivo reflect the occurrence of dendritic plateau potentials (dendritic UP states. We propose that the somatic voltage waveform during a neuronal UP state is determined by dendritic plateau potentials. A mammalian spiny neuron uses dendritic plateau potentials to detect and transform coherent network activity into a ubiquitous neuronal UP state. The biophysical properties of dendritic plateau potentials allow neurons to quickly attune to the ongoing network activity, as well as secure the stable amplitudes of successive UP states.

  1. CENTRAL PLATEAU REMEDIATION

    Energy Technology Data Exchange (ETDEWEB)

    ROMINE, L.D.

    2006-02-01

    A systematic approach to closure planning is being implemented at the Hanford Site's Central Plateau to help achieve the goal of closure by the year 2035. The overall objective of Central Plateau remediation is to protect human health and the environment from the significant quantity of contaminated material that resulted from decades of plutonium production in support of the nation's defense. This goal will be achieved either by removing contaminants or placing the residual contaminated materials in a secure configuration that minimizes further migration to the groundwater and reduces the potential for inadvertent intrusion into contaminated sites. The approach to Central Plateau cleanup used three key concepts--closure zones, closure elements, and closure process steps--to create an organized picture of actions required to complete remediation. These actions were merged with logic ties, constraints, and required resources to produce an integrated time-phased schedule and cost profile for Central Plateau closure. Programmatic risks associated with implementation of Central Plateau closure were identified and analyzed. Actions to mitigate the most significant risks are underway while high priority remediation projects continue to make progress.

  2. Adaption to High Altitude: An Evaluation of the Storage Quality of Suspended Red Blood Cells Prepared from the Whole Blood of Tibetan Plateau Migrants.

    Directory of Open Access Journals (Sweden)

    Rui Zhong

    Full Text Available Hypoxia has been reported to cause the significant enhancement of hemoglobin (Hb and hematocrit (Hct, which stabilizes at relatively high levels after an individual ascends to a high altitude. However, the quality of the suspended red blood cells (SRBCs obtained from individuals at high altitudes such as Tibetan plateau migrants after storage has not been studied. In this study, we compared the storage quality of SRBCs prepared from Tibetan plateau and Deyang lowland populations by adding a normal volume of mannitol-adenine-phosphate (MAP, which is a common additive solution used in blood storage in Asian countries. The storage cell characteristics were examined on days 1, 7, 14 and 35.We found higher Hct and Hb levels and viscosity in the high altitude samples. The metabolic rates, including those for electrolytes and lactate, were higher in plateau SRBCs than in lowland SRBCs; these findings were consistent with the higher osmotic fragility and hemolysis of plateau SRBCs throughout the entire storage period. In addition, the reduction rates of 2,3-diphosphoglycerate (2,3-DPG and oxygen tension to attain 50% oxygen saturation of Hb (P50 in plateau SRBCs were higher than those in lowland SRBCs, and the oxygen delivering capacity in plateau SRBCs was weaker than that in lowland SRBCs. We concluded that the storage quality of plateau SRBCs was inferior to that of lowland SRBCs when using the same concentration of MAP. We suggested that the optimal formula, including the MAP concentration or even a new additive solution, to store the plateau SRBCs must be assessed and regulated.

  3. Scale-Up Information for Gas-Phase Ammonia Treatment of Uranium in the Vadose Zone at the Hanford Site Central Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Truex, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Szecsody, James E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhong, Lirong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Thomle, Jonathan N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Timothy C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-09-01

    Uranium is present in the vadose zone at the Hanford Central Plateau and is of concern for protection of groundwater. The Deep Vadose Zone Treatability Test Plan for the Hanford Central Plateau identified gas-phase treatment and geochemical manipulation as potentially effective treatment approaches for uranium and technetium in the Hanford Central Plateau vadose zone. Based on laboratory evaluation, use of ammonia vapor was selected as the most promising uranium treatment candidate for further development and field testing. While laboratory tests have shown that ammonia treatment effectively reduces the mobility of uranium, additional information is needed to enable deployment of this technology for remediation. Of importance for field applications are aspects of the technology associated with effective distribution of ammonia to a targeted treatment zone, understanding the fate of injected ammonia and its impact on subsurface conditions, and identifying effective monitoring approaches. In addition, information is needed to select equipment and operational parameters for a field design. As part of development efforts for the ammonia technology for remediation of vadose zone uranium contamination, field scale-up issues were identified and have been addressed through a series of laboratory and modeling efforts. This report presents a conceptual description for field application of the ammonia treatment process, engineering calculations to support treatment design, ammonia transport information, field application monitoring approaches, and a discussion of processes affecting the fate of ammonia in the subsurface. The report compiles this information from previous publications and from recent research and development activities. The intent of this report is to provide technical information about these scale-up elements to support the design and operation of a field test for the ammonia treatment technology.

  4. 'Working' cardiomyocytes exhibiting plateau action potentials from human placenta-derived extraembryonic mesodermal cells.

    Science.gov (United States)

    Okamoto, Kazuma; Miyoshi, Shunichiro; Toyoda, Masashi; Hida, Naoko; Ikegami, Yukinori; Makino, Hatsune; Nishiyama, Nobuhiro; Tsuji, Hiroko; Cui, Chang-Hao; Segawa, Kaoru; Uyama, Taro; Kami, Daisuke; Miyado, Kenji; Asada, Hironori; Matsumoto, Kenji; Saito, Hirohisa; Yoshimura, Yasunori; Ogawa, Satoshi; Aeba, Ryo; Yozu, Ryohei; Umezawa, Akihiro

    2007-07-15

    The clinical application of cell transplantation for severe heart failure is a promising strategy to improve impaired cardiac function. Recently, an array of cell types, including bone marrow cells, endothelial progenitors, mesenchymal stem cells, resident cardiac stem cells, and embryonic stem cells, have become important candidates for cell sources for cardiac repair. In the present study, we focused on the placenta as a cell source. Cells from the chorionic plate in the fetal portion of the human placenta were obtained after delivery by the primary culture method, and the cells generated in this study had the Y sex chromosome, indicating that the cells were derived from the fetus. The cells potentially expressed 'working' cardiomyocyte-specific genes such as cardiac myosin heavy chain 7beta, atrial myosin light chain, cardiac alpha-actin by gene chip analysis, and Csx/Nkx2.5, GATA4 by RT-PCR, cardiac troponin-I and connexin 43 by immunohistochemistry. These cells were able to differentiate into cardiomyocytes. Cardiac troponin-I and connexin 43 displayed a discontinuous pattern of localization at intercellular contact sites after cardiomyogenic differentiation, suggesting that the chorionic mesoderm contained a large number of cells with cardiomyogenic potential. The cells began spontaneously beating 3 days after co-cultivation with murine fetal cardiomyocytes and the frequency of beating cells reached a maximum on day 10. The contraction of the cardiomyocytes was rhythmical and synchronous, suggesting the presence of electrical communication between the cells. Placenta-derived human fetal cells may be useful for patients who cannot supply bone marrow cells but want to receive stem cell-based cardiac therapy.

  5. Cell cycle phase regulates glucocorticoid receptor function.

    Directory of Open Access Journals (Sweden)

    Laura Matthews

    Full Text Available The glucocorticoid receptor (GR is a member of the nuclear hormone receptor superfamily of ligand-activated transcription factors. In contrast to many other nuclear receptors, GR is thought to be exclusively cytoplasmic in quiescent cells, and only translocate to the nucleus on ligand binding. We now demonstrate significant nuclear GR in the absence of ligand, which requires nuclear localisation signal 1 (NLS1. Live cell imaging reveals dramatic GR import into the nucleus through interphase and rapid exclusion of the GR from the nucleus at the onset of mitosis, which persists into early G(1. This suggests that the heterogeneity in GR distribution is reflective of cell cycle phase. The impact of cell cycle-driven GR trafficking on a panel of glucocorticoid actions was profiled. In G2/M-enriched cells there was marked prolongation of glucocorticoid-induced ERK activation. This was accompanied by DNA template-specific, ligand-independent GR transactivation. Using chimeric and domain-deleted receptors we demonstrate that this transactivation effect is mediated by the AF1 transactivation domain. AF-1 harbours multiple phosphorylation sites, which are consensus sequences for kinases including CDKs, whose activity changes during the cell cycle. In G2/M there was clear ligand independent induction of GR phosphorylation on residues 203 and 211, both of which are phosphorylated after ligand activation. Ligand-independent transactivation required induction of phospho-S211GR but not S203GR, thereby directly linking cell cycle driven GR modification with altered GR function. Cell cycle phase therefore regulates GR localisation and post-translational modification which selectively impacts GR activity. This suggests that cell cycle phase is an important determinant in the cellular response to Gc, and that mitotic index contributes to tissue Gc sensitivity.

  6. Monitoring stem cells in phase contrast imaging

    Science.gov (United States)

    Lam, K. P.; Dempsey, K. P.; Collins, D. J.; Richardson, J. B.

    2016-04-01

    Understanding the mechanisms behind the proliferation of Mesenchymal Stem cells (MSCs) can offer a greater insight into the behaviour of these cells throughout their life cycles. Traditional methods of determining the rate of MSC differentiation rely on population based studies over an extended time period. However, such methods can be inadequate as they are unable to track cells as they interact; for example, in autologous cell therapies for osteoarthritis, the development of biological assays that could predict in vivo functional activity and biological action are particularly challenging. Here further research is required to determine non-histochemical biomarkers which provide correlations between cell survival and predictive functional outcome. This paper proposes using a (previously developed) advanced texture-based analysis algorithm to facilitate in vitro cells tracking using time-lapsed microscopy. The technique was adopted to monitor stem cells in the context of unlabelled, phase contrast imaging, with the goal of examining the cell to cell interactions in both monoculture and co-culture systems. The results obtained are analysed using established exploratory procedures developed for time series data and compared with the typical fluorescent-based approach of cell labelling. A review of the progress and the lessons learned are also presented.

  7. Modeling the Physical Multi-Phase Interactions of HNO3 Between Snow and Air on the Antarctic Plateau (Dome C) and coast (Halley)

    Science.gov (United States)

    Chan, Hoi Ga; Frey, Markus M.; King, Martin D.

    2017-04-01

    Nitrogen oxides (NOx = NO + NO2) emissions from nitrate (NO3-) photolysis in snow affect the oxidising capacity of the lower troposphere especially in remote regions of the high latitudes with low pollution levels. The porous structure of snowpack allows the exchange of gases with the atmosphere driven by physicochemical processes, and hence, snow can act as both source and sink of atmospheric chemical trace gases. Current models are limited by poor process understanding and often require tuning parameters. Here, two multi-phase physical models were developed from first principles constrained by observed atmospheric nitrate, HNO3, to describe the air-snow interaction of nitrate. Similar to most of the previous approaches, the first model assumes that below a threshold temperature, To, the air-snow grain interface is pure ice and above To, a disordered interface (DI) emerges assumed to be covering the entire grain surface. The second model assumes that Air-Ice interactions dominate over the entire temperature range below melting and that only above the eutectic temperature, liquid is present in the form of micropockets in grooves. The models are validated with available year-round observations of nitrate in snow and air at a cold site on the Antarctica Plateau (Dome C, 75°06'S, 123°33'E, 3233 m a.s.l.) and at a relatively warm site on the Antarctica coast (Halley, 75°35'S, 26°39'E, 35 m a.s.l). The first model agrees reasonably well with observations at Dome C (Cv(RMSE) = 1.34), but performs poorly at Halley (Cv(RMSE) = 89.28) while the second model reproduces with good agreement observations at both sites without any tuning (Cv(RMSE) = 0.84 at both sites). It is therefore suggested that air-snow interactions of nitrate in the winter are determined by non-equilibrium surface adsorption and co-condensation on ice coupled with solid-state diffusion inside the grain. In summer, however, the air-snow exchange of nitrate is mainly driven by solvation into liquid

  8. Localized plateau beam resulting from strong nonlocal coupling in a cavity filled by metamaterials and liquid-crystal cells

    Science.gov (United States)

    Tlidi, M.; Fernandez-Oto, C.; Clerc, M. G.; Escaff, D.; Kockaert, P.

    2015-11-01

    We investigate the formation of a localized plateau beam in the transverse section of a nonlinear optical ring cavity filled with a metamaterial and a nonlocal medium such as a nematic liquid crystal. We show that, far from the modulational instability regime, localized structures with a varying width may be stable in one and two-dimensional settings. The mechanism of stabilization is related with strong nonlocal coupling mediated by a Lorentzian type of kernel. We show that there exists stable bright and dark localized structures. A reduction of Lugiato-Lefever equation in the regime close to the nascent bistability allows us to analytically derive a simple formula for the width of localized structures in one-dimensional systems. Direct numerical simulations of the dynamical model agree with the analytical predictions.

  9. Industrialization of polymer solar cells - phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Lauritzen, H.; Krebs, F.C. [Technical Univ. of Denmark. DTU Energy Conversion, DTU Risoe Campus, Roskilde (Denmark); Andersen, Rasmus B. [Mekoprint A/S, Stoevrimg (Denmark); Bork, J.; Bentzen, B.

    2012-03-15

    A three-phased project with the objective to industrialize DTU's basic polymer solar cell technology was started in the summer of 2009. The technology comprises a specific design of the polymer solar cell and a corresponding roll-to-roll manufacturing process. This basic technology is referred to as ProcessOne in the open literature. The present report relates to the project's phase 1.The key tasks in phase 1 are to stream-line DTU's tech-nology for the industrial utilization, to demonstrate production according to this stream-lined technology at Mekoprint A/S and finally to fertilize the market for polymer solar cells by demonstrating their use in appli-cations that harmonize with their present maturity level. The main focus in the stream-lining of DTU's technology has been to demonstrate a convincing rate of reduction for the production cost, and thereby make a competitive price plausible. This has been materialized as a learning curve showing that the polymer technology presently develops considerably faster than the silicon technology. The polymer solar cells will, under the assumption that both technologies follow a projection of the learning curve, gain a cost-leading position within a reasonable time. A production cost of 5 Euro/Wp has already been demonstrated in DTU's pilot plant, and a road map for the further decrease to 1 Euro/Wp is drawn. This target is expected to be reached in 2013 in the ongoing phase 2 of the project. Another activity essential for the industrialization has been the launch of specialized materials, equipment and services required for the processing of DTU's polymer solar cells. Relevant products and services are made available for sale on DTU's homepage, www.energyconversion.dtu.dk. A production line for polymer solar cells has been established at Mekoprint. For this a retrofit solution was chosen where the core of an existing screen-printing line was dismantled and fitted to a slot-die printing head manufactured in DTU's workshop

  10. Industrialization of polymer solar cells - phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Lauritzen, H.; Krebs, F.C. [Technical Univ. of Denmark. DTU Energy Conversion, DTU Risoe Campus, Roskilde (Denmark); Andersen, Rasmus B. [Mekoprint A/S, Stoevrimg (Denmark); Bork, J.; Bentzen, B.

    2012-03-15

    A three-phased project with the objective to industrialize DTU's basic polymer solar cell technology was started in the summer of 2009. The technology comprises a specific design of the polymer solar cell and a corresponding roll-to-roll manufacturing process. This basic technology is referred to as ProcessOne in the open literature. The present report relates to the project's phase 1.The key tasks in phase 1 are to stream-line DTU's tech-nology for the industrial utilization, to demonstrate production according to this stream-lined technology at Mekoprint A/S and finally to fertilize the market for polymer solar cells by demonstrating their use in appli-cations that harmonize with their present maturity level. The main focus in the stream-lining of DTU's technology has been to demonstrate a convincing rate of reduction for the production cost, and thereby make a competitive price plausible. This has been materialized as a learning curve showing that the polymer technology presently develops considerably faster than the silicon technology. The polymer solar cells will, under the assumption that both technologies follow a projection of the learning curve, gain a cost-leading position within a reasonable time. A production cost of 5 Euro/Wp has already been demonstrated in DTU's pilot plant, and a road map for the further decrease to 1 Euro/Wp is drawn. This target is expected to be reached in 2013 in the ongoing phase 2 of the project. Another activity essential for the industrialization has been the launch of specialized materials, equipment and services required for the processing of DTU's polymer solar cells. Relevant products and services are made available for sale on DTU's homepage, www.energyconversion.dtu.dk. A production line for polymer solar cells has been established at Mekoprint. For this a retrofit solution was chosen where the core of an existing screen-printing line was dismantled and fitted to a slot-die printing head manufactured in DTU's workshop

  11. PHASE I SINGLE CELL ELECTROLYZER TEST RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    Steimke, J; Timothy Steeper, T

    2008-08-05

    This document reports the results of Phase I Single Cell testing of an SO{sub 2}-Depolarized Water Electrolyzer. Testing was performed primarily during the first quarter of FY 2008 at the Savannah River National Laboratory (SRNL) using an electrolyzer cell designed and built at SRNL. Other facility hardware were also designed and built at SRNL. This test further advances this technology for which work began at SRNL in 2005. This research is valuable in achieving the ultimate goal of an economical hydrogen production process based on the Hybrid Sulfur (HyS) Cycle. The focus of this work was to conduct single cell electrolyzer tests to further develop the technology of SO{sub 2}-depolarized electrolysis as part of the HyS Cycle. The HyS Cycle is a hybrid thermochemical cycle that may be used in conjunction with advanced nuclear reactors or centralized solar receivers to produce hydrogen by water-splitting. Like all other sulfur-based cycles, HyS utilizes the high temperature thermal decomposition of sulfuric acid to produce oxygen and regenerate sulfur dioxide. The unique aspect of HyS is the generation of hydrogen in a water electrolyzer that is operated under conditions where dissolved sulfur dioxide depolarizes the anodic reaction, resulting in substantial voltage reduction. Low cell voltage is essential for both thermodynamic efficiency and hydrogen cost. Sulfur dioxide is oxidized at the anode, producing sulfuric acid that is sent to the high temperature acid decomposition portion of the cycle. The electrolyzer cell uses the membrane electrode assembly (MEA) concept. The anode and cathode are formed by spraying platinum containing catalyst on both sides of a Proton Exchange Membrane (PEM). In most testing the material of the PEM was NafionR. The electrolyzer cell active area can be as large as 54.8 cm{sup 2}. Feed to the anode of the electrolyzer is a sulfuric acid solution containing sulfur dioxide. The partial pressure of sulfur dioxide could be varied in the

  12. Phase Space Cell in Nonextensive Classical Systems

    Directory of Open Access Journals (Sweden)

    Piero Quarati

    2003-06-01

    Full Text Available Abstract: We calculate the phase space volume Ω occupied by a nonextensive system of N classical particles described by an equilibrium (or steady-state, or long-term stationary state of a nonequilibrium system distribution function, which slightly deviates from Maxwell-Boltzmann (MB distribution in the high energy tail. We explicitly require that the number of accessible microstates does not change respect to the extensive MB case. We also derive, within a classical scheme, an analytical expression of the elementary cell that can be seen as a macrocell, different from the third power of Planck constant. Thermodynamic quantities like entropy, chemical potential and free energy of a classical ideal gas, depending on elementary cell, are evaluated. Considering the fractional deviation from MB distribution we can deduce a physical meaning of the nonextensive parameter q of the Tsallis nonextensive thermostatistics in terms of particle correlation functions (valid at least in the case, discussed in this work, of small deviations from MB standard case.

  13. Ab initio based Monte Carlo studies of Cu-depleted CIS phases for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, Christian; Gruhn, Thomas; Felser, Claudia [Institut fuer Anorganische and Analytische Chemie, Johannes Gutenberg-Universitaet Mainz (Germany); Windeln, Johannes [IBM Mainz (Germany)

    2011-07-01

    Thin film solar cells with a CuInSe{sub 2} (CIS) absorber layer have an increasing share of the solar cell market because of their low production costs and the high efficiency. One interesting aspect of CIS is the inherent resilience to defects and composition fluctuations. Beside the stable CuInSe{sub 2} phase, there are various Cu-poor phases along the Cu{sub 2}Se-In{sub 2}Se{sub 3} tie line, including the CuIn{sub 3}Se{sub 5} and the CuIn{sub 5}Se{sub 8} phase. We have used ab initio calculations of Cu-poor CIS configurations to make a cluster expansion of the configurational energy. In the configurations, Cu atoms, In atoms, and vacancies are distributed over the Cu and In sites of a CIS cell with fixed Se atoms. With the resulting energy expression, CuIn{sub 3}Se{sub 5} and CuIn{sub 5}Se{sub 8} systems have been studied in the canonical ensemble. By analyzing the free energy landscape the transition temperature between a low-temperature ordered and a high-temperature disordered CuIn{sub 5}Se{sub 8} phase has been determined. Furthermore, grandcanonical ensemble simulations have been carried out, which provide the equilibrium Cu and In concentrations as a function of the chemical potentials {mu}{sub Cu} and {mu}{sub In}. Plateau regions for the CuInSe{sub 2} and the CuIn{sub 5}Se{sub 8} phases have been found and analyzed for different temperatures.

  14. Tibial Plateau Fractures

    DEFF Research Database (Denmark)

    Elsøe, Rasmus

    This PhD thesis reported an incidence of tibial plateau fractures of 10.3/100,000/year in a complete Danish regional population. The results reported that patients treated for a lateral tibial plateau fracture with bone tamp reduction and percutaneous screw fixation achieved a satisfactory level...... with only the subgroup Sport significantly below the age matched reference population. The thesis reports a level of health related quality of life (Eq5d) and disability (KOOS) significantly below established reference populations for patients with bicondylar tibial plateau fracture treated with a ring...... fixator, both during treatment and at 19 months following injury. In general, the thesis demonstrates that the treatment of tibial plateau fractures are challenging and that some disabilities following these fractures must be expected. Moreover, the need for further research in the area, both with regard...

  15. Phase-shifting interferometric holography of living cells

    Science.gov (United States)

    Giel, Dominik M.; Fratz, Markus; Brandenburg, Albrecht

    2006-02-01

    We present a phase-shifting holographic set-up for the microscopic imaging of adherent cells. The superposition of an object wave field and a reference wave is recorded on a digital sensor with three reference wave phases. The reference phases are then recovered by statistical analysis of the recorded intensities. Subsequently, the object wave phase is calculated by the generalized phase shifting algorithm. After phase unwrapping and background subtraction, the phase shift introduced by the adherent cell culture is reconstructed. As the interferograms are recorded in the image plane of the microsope objective, the full lateral resolution is achieved in contrast to off-axis holography where the reconstruction requires numerical propagation for the separation of 0 th and 1 st order. Our approach uses three arbitrary unknown reference phases and poses thus minimum requirements on the mechanical and thermal stability of the set-up. We give preliminary results of images from a Vero cell line and pollen grains.

  16. Phase coding by grid cells in unconstrained environments: Two-dimensional (2D) phase precession

    Science.gov (United States)

    Climer, Jason R.; Newman, Ehren L.; Hasselmo, Michael E.

    2014-01-01

    Action potential timing is thought to play a critical role in neural representation. For example, theta phase precession is a robust phenomenon exhibited by spatial cells of the rat entorhinal-hippocampal circuit. In phase precession, the time a neuron fires relative to the phase of theta rhythm (6-10Hz) oscillations in the local field potential reduces uncertainty about the position of the animal. This relationship between neural firing and behavior has made precession an important constraint for hypothetical mechanisms of temporal coding. However, challenges exist in identifying what regulates the spike timing of these cells. We have developed novel analytical techniques for mapping between behavior and neural firing that provide sufficient sensitivity to examine features of grid cell phase coding in open environments. Here, we show robust, omnidirectional phase precession by entorhinal grid cells in openfield enclosures. We present evidence that full phase precession persists regardless of how close the animal comes to the center of a firing field. We found many conjunctive grid cells, previously thought to be phase locked, also exhibit phase coding. However, we were unable to detect directional or field specific phase coding predicted by some variants of models. Finally, we present data that suggests bursting of layer II grid cells contributes to the bimodality of phase precession. We discuss implications of these observations for models of temporal coding and propose the utility of these techniques in other domains where behavior is aligned to neural spiking. PMID:23718553

  17. Inter-machine comparison of the termination phase and energy conversion in tokamak disruptions with runaway current plateau formation and implications for ITER

    Science.gov (United States)

    Martín-Solís, J. R.; Loarte, A.; Hollmann, E. M.; Esposito, B.; Riccardo, V.; FTU; DIII-D Teams; EFDA Contributors, JET

    2014-08-01

    The termination of the current and the loss of runaway electrons following runaway current plateau formation during disruptions have been investigated in the JET, DIII-D and FTU tokamaks. Substantial conversion of magnetic energy into runaway kinetic energy, up to ˜10 times the initial plateau runaway kinetic energy, has been inferred for the slowest current terminations. Both modelling and experiment suggest that, in present devices, the efficiency of conversion into runaway kinetic energy is determined to a great extent by the characteristic runaway loss time, τdiff, and the resistive time of the residual ohmic plasma after the disruption, τres, increasing with the ratio τdiff/τres. It is predicted that, in large future devices such as ITER, the generation of runaways by the avalanche mechanism will play an important role, particularly for slow runaway discharge terminations, increasing substantially the amount of energy deposited by the runaways onto the plasma-facing components by the conversion of magnetic energy of the runaway plasma into runaway kinetic energy. Estimates of the power fluxes on the beryllium plasma-facing components during runaway termination in ITER indicate that for runaway currents of up to 2 MA no melting of the components is expected. For larger runaway currents, minimization of the effects of runaway impact on the first wall requires a reduction in the kinetic energy of the runaway beam before termination and, in addition, high plasma density ne and low ohmic plasma resistance (long τres) to prevent large conversion of magnetic into runaway kinetic energy during slow current terminations.

  18. Plateau-insulator transition in graphene

    Energy Technology Data Exchange (ETDEWEB)

    Amado, M; Diez, E; Caridad, J M [Laboratorio de Bajas Temperaturas, Universidad de Salamanca, E-37008 Salamanca (Spain); Lopez-Romero, D [CT-ISOM, Universidad Politecnica de Madrid, E-28040 Madrid (Spain); Rossella, F; Dionigi, F; Bellani, V [Dipartimento di Fisica ' A Volta' and CNISM, Universita degli studi di Pavia, I-27100 Pavia (Italy); Maude, D K, E-mail: marioam@fis.ucm.e [Laboratoire National des Champs Magnetiques Intenses, F-38042 Grenoble (France)

    2010-05-15

    We investigate the quantum Hall effect (QHE) in a graphene sample with Hall-bar geometry close to the Dirac point at high magnetic fields up to 28 T. We have discovered a plateau-insulator quantum phase transition passing from the last plateau for the integer QHE in graphene to an insulator regime {nu}=-2{yields}{nu}=0. The analysis of the temperature dependence of the longitudinal resistance gives a value for the critical exponent associated with the transition equal to {kappa}=0.58{+-}0.03.

  19. Heat production of mammalian cells at different cell-cycle phases

    NARCIS (Netherlands)

    Loesberg, C.; Miltenburg, J.C. van; Wuk, R. van

    1982-01-01

    1. 1.|Heat production of Reuber H35 rat hepatoma cells and murine C1300 neuroblastoma cells at different stages of the cell cycle were measured microcalorimetrically. 2. 2.|Reuber H35 monolayer cultures of G1-phase cells and cells in S-phase were trypsinized, reincubated in suspension culture and i

  20. Radiative plateau inflation

    CERN Document Server

    Ballesteros, Guillermo

    2016-01-01

    We describe how monomial chaotic inflation becomes compatible with the latest CMB data thanks to radiative corrections producing a plateau. The interactions of the inflation with other fields, required for reheating, can flatten the potential and moderate the production of primordial gravitational waves, keeping these below the current upper bound. We show that the appearance of a plateau requires that the inflaton couples to fermions and to another scalar or a gauge group. We give concrete examples of minimal particle physics models leading to plateaus for quadratic and quartic chaotic inflation. We also provide a three-parameter model-independent description of radiatively corrected inflation that is amenable to CMB analyses.

  1. Industrialisation of polymer solar cells. Phase 2: Consolidation

    DEFF Research Database (Denmark)

    Lauritzen, Hanne; Gevorgyan, Suren; Frausig, Jesper

    The present report refers to the project “Industrialization of polymer solar cellsphase 2”. Both the project and this report build directly upon the prior phase 1 where the basic OPV technology, ProcessOne, was transferred to Mekoprint. This second phase focuses on an anchoring of the transfer......The present report refers to the project “Industrialization of polymer solar cellsphase 2”. Both the project and this report build directly upon the prior phase 1 where the basic OPV technology, ProcessOne, was transferred to Mekoprint. This second phase focuses on an anchoring...... of the transferred technology in Mekoprint’s industrial environment and an anchoring of the technology as an attractive solution for low-demanding PV applications. This second phase is also concerned with DTU’s further development of the OPV technology towards DTU’s ultimate goal of qualifying OPV for large...

  2. STAGING OF FUEL CELLS - PHASE II

    Energy Technology Data Exchange (ETDEWEB)

    Per Onnerud; Suresh Sriramulu

    2002-08-29

    TIAX has executed a laboratory-based development program aiming at the improvement of stationary fuel cell systems. The two-year long development program resulted in an improved understanding of staged fuel cells and inorganic proton conductors through evaluation of results from a number of laboratory tasks: (1) Development of a fuel cell modeling tool--Multi-scale model was developed, capable of analyzing the effects of materials and operating conditions; and this model allowed studying various ''what-if'' conditions for hypothetically staged fuel cells; (2) Study of new high temperature proton conductor--TIAX discovery of a new class of sulfonated inorganics capable of conducting protons when exposed to water; and study involved synthesis and conductivity measurements of novel compounds up to 140 C; (3) Electrochemical fuel cell measurements--the feasibility of staged fuel cells was tested in TIAX's fuel cell laboratories experimental design was based on results from modeling.

  3. Interactive cell segmentation based on phase contrast optics.

    Science.gov (United States)

    Su, Hang; Su, Zhou; Zheng, Shibao; Yang, Hua; Wei, Sha

    2014-01-01

    Cell segmentation in phase contrast microscopy images lays a crucial foundation for numerous subsequent computer-aided cell image analysis, but it encounters many unsolved challenges due to image qualities and artifacts caused by phase contrast optics. Addressing the unsolved challenges, the authors propose an interactive cell segmentation scheme over phase retardation features. After partitioning the images into phase homogeneous atoms, human annotations are propagated to unlabeled atoms over an affinity graph that is learned based on discrimination analysis. Then, an active query strategy is proposed for which the most informative unlabeled atom is selected for annotation, which is also propagated to the other unlabeled atoms. Cell segmentation converges to quality results after several rounds of interactions involving both the user's intentions and characteristics of image features. Experimental results demonstrate that cells with different optical properties are well segmented via the proposed approach.

  4. Plateau Indian Ways with Words

    Science.gov (United States)

    Monroe, Barbara

    2009-01-01

    The indigenous rhetoric of the Plateau Indians continues to exert a discursive influence on student writing in reservation schools today. Plateau students score low on state-mandated tests and on college writing assignments, in large part because the pervasive personalization of Plateau rhetoric runs counter to the depersonalization of academic…

  5. Greening the Plateau

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Located on the world’s largest plateau, Tibet Autonomous Region in China’s southwest has an average elevation of 4,000 meters. Tibet’s diverse natural landscapes, including snow-capped mountains, vast pastures and virgin forests, combined with its

  6. Heat Stress Induces Extended Plateau of Hsp70 Accumulation--A Possible Cytoprotection Mechanism in Hepatic Cells.

    Science.gov (United States)

    Miova, Biljana; Dinevska-Kjovkarovska, Suzana; Esplugues, Juan V; Apostolova, Nadezda

    2015-10-01

    The relevance of heat preconditioning resides in its ability to protect cells from different kinds of injury by induction of heat shock proteins, a process in which the intensity of heat stress (HS) and duration of subsequent recovery are vital. This study evaluates the effects of moderate HS (45 min/43°C) and the time-dependent changes during recovery period of HSP70, Bcl-2 and p53 gene and protein expression in HepG2 cells. We also evaluated the effects of 0.4 mM aspirin (ASA) as a potential pharmacological co-inducer of HSP, both alone and in a combination with HS (ASA + HS). HS alone and ASA + HS caused a major up-regulation of HSP70 mRNA in the first 2 h, while HSP70 protein increased gradually and was especially abundant from 2 h to 24 h. Regarding Bcl-2, all treatments rendered similar results: gene expression was down-regulated in the first 2 h, after which there was protein elevation (12-48 h after HS). mRNA expression of p53 in HS- and (ASA + HS)-cells was down-regulated in the first 12 h. The immediate decrease of p53 protein after HS was followed by a biphasic increase. In conclusion, 0.4 mM ASA + HS does not act as a co-inducer of HSP70 in HepG2 cells, but promotes Bcl-2 protein expression during prolonged treatment. Our suggestion is that hepatic cells are most vulnerable in the first 2-6 h, but may have a high capacity for combating stress 12-24 h after HS. Finally, short-term exposure HS might be a "physiological conditioner" for liver cells to accumulate HSP and Bcl-2 proteins and thus obtain cytoprotection against an additional stress.

  7. Institute of Tibetan Plateau Research

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ The Tibetan Plateau (Qinghai-Xizang Plateau)is a unique geological-geographical unit on Earth, an ideal region for studies into the formation and evolution of the lithosphere and the dynamic mechanism of the earth crust. The uplifting of the Plateau exerts profound influence upon the evolution and differentiation of the natural environment of the plateau itself, its adjacent regions and the Northern Hemisphere. As a unique natural geographical unit, the Plateau holds a special status in the whole globe due to its special natural environment and ecosystems, which is also in close relation to global environmental change.The significance of the Plateau research should be recognized not only in the fundamental research fields of geo-sciences and biology, but also in its application to resource exploitation, environmental protection and sustainable development of the Plateau region.

  8. Phases I–III Clinical Trials Using Adult Stem Cells

    OpenAIRE

    Ricardo Sanz-Ruiz; Enrique Gutiérrez Ibañes; Adolfo Villa Arranz; María Eugenia Fernández Santos; Pedro L. Sánchez Fernández; Francisco Fernández-Avilés

    2010-01-01

    First randomized clinical trials have demonstrated that stem cell therapy can improve cardiac recovery after the acute phase of myocardial ischemia and in patients with chronic ischemic heart disease. Nevertheless, some trials have shown that conflicting results and uncertainties remain in the case of mechanisms of action and possible ways to improve clinical impact of stem cells in cardiac repair. In this paper we will examine the evidence available, analyze the main phase I and II randomize...

  9. On robustness of phase resetting to cell division under entrainment.

    Science.gov (United States)

    Ahmed, Hafiz; Ushirobira, Rosane; Efimov, Denis

    2015-12-21

    The problem of phase synchronization for a population of genetic oscillators (circadian clocks, synthetic oscillators, etc.) is considered in this paper, taking into account a cell division process and a common entrainment input in the population. The proposed analysis approach is based on the Phase Response Curve (PRC) model of an oscillator (the first order reduced model obtained for the linearized system and inputs with infinitesimal amplitude). The occurrence of cell division introduces state resetting in the model, placing it in the class of hybrid systems. It is shown that without common entraining input in all oscillators, the cell division acts as a disturbance causing phase drift, while the presence of entrainment guarantees boundedness of synchronization phase errors in the population. The performance of the obtained solutions is demonstrated via computer experiments for two different models of circadian/genetic oscillators (Neurospora׳s circadian oscillation model and the repressilator).

  10. Endurance characteristics of phase change memory cells

    Science.gov (United States)

    Ruru, Huo; Daolin, Cai; Chen, Bomy; Yifeng, Chen; Yuchan, Wang; Yueqing, Wang; Hongyang, Wei; Qing, Wang; Yangyang, Xia; Dan, Gao; Zhitang, Song

    2016-05-01

    The endurance characteristics of phase change memory are studied. With operational cycles, the resistances of reset and set states gradually change to the opposite direction. What is more, the operational conditions that are needed are also discussed. The failure and the changes are concerned with the compositional change of the phase change material. An abnormal phenomenon that the threshold voltage decreases slightly at first and then increases is observed, which is due to the coaction of interface contact and growing active volume size changing. Project supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA09020402), the National Key Basic Research Program of China (Nos. 2013CBA01900, 2010CB934300, 2011CBA00607, 2011CB932804), the National Integrate Circuit Research Program of China (No. 2009ZX02023-003), the National Natural Science Foundation of China (No. 61176122, 61106001, 61261160500, 61376006), and the Science and Technology Council of Shanghai (Nos. 12nm0503701, 13DZ2295700, 12QA1403900, 13ZR1447200, 14ZR1447500).

  11. White ash (Fraxinus americana) health in the Allegheny plateau region, Pennsylvania: Evaluating the relationship between FIA phase 3 crown variables and a categorical rating system

    Science.gov (United States)

    Alejandro A. Royo; Kathleen S. Knight; Jamie M. Himes; Ashley N. Will

    2012-01-01

    Following the detection of white ash (Fraxinus americana) decline in the Allegheny National Forest (ANF) of Pennsylvania, we established an intensified white ash monitoring network throughout the ANF. We rated crowns using both a categorical system as well as Forest Inventory and Analyses (FIA) Phase 3 measures of uncompacted live crown ratio,...

  12. The effects of menstrual cycle phase on the incidence of plateau at V˙O2max and associated cardiorespiratory dynamics.

    Science.gov (United States)

    Gordon, Dan; Scruton, Adrian; Barnes, Richard; Baker, James; Prado, Luciano; Merzbach, Viviane

    2017-09-14

    The purpose of this study was to examine the effect of menstrual cycle phase on maximal oxygen uptake (V˙O2max) and associated cardiodynamic responses. A total of 16 active females volunteered of which n = 10 formed the non-oral contraceptive pill group (n-OCP), displaying a regular menstrual cycle of 28·4 ± 2·2 days (age 20·6 ± 1·6 years, height 169·9 ± 6·4 cm, mass 68·7 ± 7·9 kg) and n = 6 formed the oral contraceptive pill group (OCP) (monophasic pill) (age 21·7 years ± 2·16, height 168·1 cm ± 6·8 cm, mass 61·6 ± 6·8 kg). Each completed four incremental exercise tests for determination of V˙O2max, cardiac output, stroke volume and heart rate. Each test was completed according to the phases of the menstrual cycle as determined through salivary analysis of 17-β oestrodiol and progesterone. Non-significant differences were observed for V˙O2max across phases and between groups (P>0·05) with additional non-significant differences for Q˙max, HRmax and SVmax between groups. For ∆ V˙O2 during the final 60 s of the V˙O2max trial, significant differences were observed between OCP and n-OCP (Pmenstrual cycle phase but caution should be applied when evaluating maximal oxygen uptake in females who are administered a monophasic oral contraceptive pill. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  13. SNAILs promote G1 phase in selected cancer cells.

    Science.gov (United States)

    Wu, Ya-Lan; Xue, Jian-Xin; Zhou, Lin; Deng, Lei; Shang, Yan-Na; Liu, Fang; Mo, Xian-Ming; Lu, You

    2015-11-01

    Cells can acquire a stem-like cell phenotype through epithelial-mesenchymal transition (EMT). However, it is not known which of the stem-like cancer cells are generated by these phenotype transitions. We studied the EMT-inducing roles of SNAILs (the key inducers for the onset of EMT) in selected cancer cells (lung cancer cell line with relatively stable genome), in order to provide more implications for the investigation of EMT-related phenotype transitions in cancer. However, SNAILs fail to induce completed EMT. In addition, we proved that Snail accelerates the early G1 phase whereas Slug accelerates the late G1 phase. Blocking G1 phase is one of the basic conditions for the onset of EMT-related phenotype transitions (e.g., metastasis, acquiring stemness). The discovery of this unexpected phenomenon (promoting G1 phase) typically reveals the heterogeneity of cancer cells. The onset of EMT-related phenotype transitions in cancer needs not only the induction and activation of SNAILs, but also some particular heredity alterations (genetic or epigenetic alterations, which cause heterogeneity). The new connection between heredity alteration (heterogeneity) and phenotype transition suggests a novel treatment strategy, the heredity alteration-directed specific target therapy. Further investigations need to be conducted to study the relevant heredity alterations.

  14. The Phase Space Elementary Cell in Classical and Generalized Statistics

    Directory of Open Access Journals (Sweden)

    Piero Quarati

    2013-10-01

    Full Text Available In the past, the phase-space elementary cell of a non-quantized system was set equal to the third power of the Planck constant; in fact, it is not a necessary assumption. We discuss how the phase space volume, the number of states and the elementary-cell volume of a system of non-interacting N particles, changes when an interaction is switched on and the system becomes or evolves to a system of correlated non-Boltzmann particles and derives the appropriate expressions. Even if we assume that nowadays the volume of the elementary cell is equal to the cube of the Planck constant, h3, at least for quantum systems, we show that there is a correspondence between different values of h in the past, with important and, in principle, measurable cosmological and astrophysical consequences, and systems with an effective smaller (or even larger phase-space volume described by non-extensive generalized statistics.

  15. Phases I–III Clinical Trials Using Adult Stem Cells

    Directory of Open Access Journals (Sweden)

    Ricardo Sanz-Ruiz

    2010-01-01

    Full Text Available First randomized clinical trials have demonstrated that stem cell therapy can improve cardiac recovery after the acute phase of myocardial ischemia and in patients with chronic ischemic heart disease. Nevertheless, some trials have shown that conflicting results and uncertainties remain in the case of mechanisms of action and possible ways to improve clinical impact of stem cells in cardiac repair. In this paper we will examine the evidence available, analyze the main phase I and II randomized clinical trials and their limitations, discuss the key points in the design of future trials, and depict new directions of research in this fascinating field.

  16. Industrialization of Polymer Solar Cellsphase 1

    DEFF Research Database (Denmark)

    Lauritzen, Hanne; Bork, Jakob; Andersen, Rasmus B.

    Polymer solar cells have unique features such as low weight, slim outline, robustness against breakage and excellent adaptability of size, shape and curvature to the actual application. These features open, not only for cost- and energy effective application of the cell, but also for aesthetic...... in the summer of 2009. The technology comprises a specific design of the polymer solar cell and a corresponding roll-to-roll manufacturing process. This basic technology is referred to as ProcessOne in the open literature. The present report relates to the project’s phase 1.The key tasks in phase 1...... are to stream-line DTU’s tech-nology for the industrial utilization, to demonstrate production according to this stream-lined technology at Mekoprint A/S and finally to fertilize the market for polymer solar cells by demonstrating their use in appli-cations that harmonize with their present maturity level...

  17. Thermoelectric Effects in Simulations of Phase Change Memory Mushroom Cells

    Science.gov (United States)

    Faraclas, Azer; Bakan, Gokhan; Gokirmak, Ali; Silva, Helena

    2012-02-01

    Phase change memory is a potential candidate for the future of high-speed non-volatile memory, however significant improvements in cell design is crucial for its success in the mainstream market. Due to the asymmetric geometry of phase change mushroom cells and the high temperature gradients generated, thermoelectric effects play a key role in determining energy consumption, cell performance, and reliability. In this study, rotationally symmetric 2D finite element simulations using COMSOL Multiphysics are implemented for GeSbTe (GST). Temperature dependent material parameters (electrical conductivity, thermal conductivity, heat capacity, and Seebeck coefficient) are included in the model for accuracy. Switching the direction of current shows a large change in peak molten volume within the cell, as well as current and power consumption.

  18. Unstained viable cell recognition in phase-contrast microscopy

    Science.gov (United States)

    Skoczylas, M.; Rakowski, W.; Cherubini, R.; Gerardi, S.

    2011-09-01

    Individual cell recognition is a relevant task to be accomplished when single-ion microbeam irradiations are performed. At INFN-LNL facility cell visualization system is based on a phase-contrast optical microscope, without the use of any cell dye. Unstained cells are seeded in the special designed Petri dish, between two mylar foils, and at present the cell recognition is achieved manually by an expert operator. Nevertheless, this procedure is time consuming and sometimes it could be not practical if the amount of living cells to be irradiated is large. To reduce the time needed to recognize unstained cells on the Petri dish, it has been designed and implemented an automated, parallel algorithm. Overlapping ROIs sliding in steps over the captured grayscale image are firstly pre-classified and potential cell markers for the segmentation are obtained. Segmented objects are additionally classified to categorize cell bodies from other structures considered as sample dirt or background. As a result, cell coordinates are passed to the dedicated CELLView program that controls all the LNL single-ion microbeam irradiation protocol, including the positioning of individual cells in front of the ion beam. Unstained cell recognition system was successfully tested in experimental conditions with two different mylar surfaces. The recognition time and accuracy was acceptable, however, improvements in speed would be useful.

  19. Unremitting Cell Proliferation in the Secretory Phase of Eutopic Endometriosis

    Science.gov (United States)

    Franco-Murillo, Yanira; Miranda-Rodríguez, José Antonio; Rendón-Huerta, Erika; Montaño, Luis F.; Cornejo, Gerardo Velázquez; Gómez, Lucila Poblano; Valdez-Morales, Francisco Javier; Gonzalez-Sanchez, Ignacio

    2014-01-01

    Objective: Endometriosis is linked to altered cell proliferation and stem cell markers c-kit/stem cell factor (SCF) in ectopic endometrium. Our aim was to investigate whether c-kit/SCF also plays a role in eutopic endometrium. Design: Eutopic endometrium obtained from 35 women with endometriosis and 25 fertile eumenorrheic women was analyzed for in situ expression of SCF/c-kit, Ki67, RAC-alpha serine/threonine-protein kinase (Akt), phosphorylated RAC-alpha serine/threonin-protein kinase (pAkt), Glycogen synthase kinase 3 beta (GSK3β), and phosphorylated glycogen synthase kinase 3 beta (pGSK3β), throughout the menstrual cycle. Results: Expression of Ki67 and SCF was higher in endometriosis than in control tissue (P < .05) and greater in secretory rather than proliferative (P < .01) endometrium in endometriosis. Expression of c-kit was also higher in endometriosis although similar in both phases. Expression of Akt and GSK3β was identical in all samples and cycle phases, whereas pAkt and pGSK3β, opposed to control tissue, remained overexpressed in the secretory phase in endometriosis. Conclusion: Unceasing cell proliferation in the secretory phase of eutopic endometriosis is linked to deregulation of c-kit/SCF-associated signaling pathways. PMID:25194152

  20. Enlightening intracellular complexity of living cells with quantitative phase microscopy

    Science.gov (United States)

    Martinez Torres, C.; Laperrousaz, B.; Berguiga, L.; Boyer Provera, E.; Elezgaray, J.; Nicolini, F. E.; Maguer-Satta, V.; Arneodo, A.; Argoul, F.

    2016-03-01

    The internal distribution of refractive indices (RIs) of a living cell is much more complex than usually admitted in multi-shell models. The reconstruction of RI maps from single phase images has rarely been achieved for several reasons: (i) we still have very little knowledge of the impact of internal macromolecular complexes on the local RI and (ii) phase changes produced by light propagation through the sample are mixed with diffraction effects by internal cell bodies. We propose the implementation a 2D wavelet-based contour chain detection method to distinguish internal boundaries thanks to their greatest optical path difference gradients. These contour chains correspond to the highest image phase contrast and follow the local RI inhomogeneities linked to the intracellular structural intricacy. Their statistics and spatial distribution are morphological indicators for distinguishing cells of different origins and to follow their transformation in pathologic situations. We use this method to compare non adherent blood cells from primary and laboratory culture origins, in healthy and pathological situations (chronic myelogenous leukaemia). In a second part of this presentation, we concentrate on the temporal dynamics of the phase contour chains and we discuss the spectral decomposition of their dynamics in both health and disease.

  1. Eocene Tibetan Plateau remnants preserved in the Northwest Himalaya

    Science.gov (United States)

    van der Beek, P. A.; van Melle, J.; Guillot, S.; Pêcher, A.; Reiners, P. W.; Nicolescu, S.; Latif, M.

    2009-04-01

    The northwest Himalaya shows strongly contrasting relief, opposing deeply incised mountain ranges characterized by extremely rapid exhumation and some of the highest peaks in the world (i.e., the Karakorum range and Nanga Parbat massif) to high-elevation, low-relief areas such as the 4000-m high Deosai plateau in northern Pakistan and the 5000-m high Tso Morari in Indian Ladakh. The origin and evolution of such plateau regions in the syntaxis of the most active continental collision in the world remain elusive. Here, we report the first low-temperature thermochronology (apatite fission-track, apatite and zircon (U-Th)/He) data from the Deosai plateau and use thermal history modelling to show that it has undergone continuous slow (≤ 200 m/Myr) denudation and has thus remained tectonically stable for the last 35 Myr at least. The inferred history of constant slow denudation of the plateau contradicts the hypothesis that widespread low-relief surfaces in the northwest Himalaya result from efficient, km-scale glacial erosion during Quaternary times; such erosion would have been recorded as a phase of rapid recent denudation that is not observed in the data. Slow continuous denudation since Eocene times, i.e. only 15-20 Myr after the onset of India-Asia collision implies that the Deosai plateau surface developed early in the Himalayan history and limits the phase of orogenic relief growth in the Ladakh-Kohistan arc to the early Paleogene. Although thermochronology data do not directly record surface uplift, the simplest explanation for the inferred constant denudation rates is that the plateau had reached its present-day elevation already during the Eocene, as a later phase of surface uplift would have triggered an erosional response that would have been recorded by the thermochronology data. We use morphological analyses to characterise such plateaux and identify them at the scale of the entire northwest Himalaya and compare our thermochronological data with

  2. Continuous controllable amorphization ratio of nanoscale phase change memory cells

    Science.gov (United States)

    He, Q.; Li, Z.; Peng, J. H.; Deng, Y. F.; Zeng, B. J.; Zhou, W.; Miao, X. S.

    2014-06-01

    The controllable heat behavior, including heat generation and dissipation, is one of the most important physical problems of nanoscale phase-change memory (PCM). A method based on heat accumulation effect to control heat behavior by synthetically modulating the three parameters of applied double pulses is proposed to achieve any expected amorphization ratio. A compact model of nanoscale PCM cells is used to simulate the thermal behavior and amorphization ratio under the condition of single parameter and multi-parameter change of applied double pulses. The results are in good agreement with the experimental results. Repeated experiments also prove the feasibility of continuous controllable amorphization ratio of nanoscale phase-change materials.

  3. ALG-2 knockdown in HeLa cells results in G2/M cell cycle phase accumulation and cell death

    DEFF Research Database (Denmark)

    Høj, Berit Rahbek; la Cour, Peter Jonas Marstrand; Mollerup, Jens

    2009-01-01

    downregulation induces accumulation of HeLa cells in the G2/M cell cycle phase and increases the amount of early apoptotic and dead cells. Caspase inhibition by the pan-caspase inhibitor zVAD-fmk attenuated the increase in the amount of dead cells following ALG-2 downregulation. Thus, our results indicate...

  4. Metabolic characterization of a CHO cell size increase phase in fed-batch cultures.

    Science.gov (United States)

    Pan, Xiao; Dalm, Ciska; Wijffels, René H; Martens, Dirk E

    2017-09-26

    Normally, the growth profile of a CHO cell fed-batch process can be divided into two main phases based on changes in cell concentration, being an exponential growth phase and a stationary (non-growth) phase. In this study, an additional phase is observed during which the cell division comes to a halt but the cell growth continues in the form of an increase in cell size. The cell size increase (SI) phase occurs between the exponential proliferation phase (also called the number increase or NI phase) and the stationary phase. During the SI phase, the average volume and dry weight per cell increase threefold linearly with time. The average mAb specific productivity per cell increases linearly with the cell volume and therefore is on average two times higher in the SI phase than in the NI phase. The specific essential amino acids consumption rates per cell remain fairly constant between the NI and the SI phase, which agrees with the similar biomass production rate per cell between these two phases. Accumulation of fatty acids and formation of lipid droplets in the cells are observed during the SI phase, indicating that the fatty acids synthesis rate exceeds the demand for the synthesis of membrane lipids. A metabolic comparison between NI and SI phase shows that the cells with a larger size produce more mAb per unit of O2 and nutrient consumed, which can be used for further process optimization.

  5. Constraining properties of GRB magnetar central engines using the observed plateau luminosity and duration correlation

    NARCIS (Netherlands)

    A. Rowlinson; B.P. Gompertz; M. Dainotti; R.A.M.J. Wijers; A.J. van der Horst

    2014-01-01

    An intrinsic correlation has been identified between the luminosity and duration of plateaus in the X-ray afterglows of gamma-ray bursts (GRBs; Dainotti et al. 2008), suggesting a central engine origin. The magnetar central engine model predicts an observable plateau phase, with plateau durations an

  6. TNX GeoSiphon Cell (TGSC-1) Phase II Single Cell Deployment/Demonstration Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Phifer, M.A.

    1999-04-15

    This Phase II final report documents the Phase II testing conducted from June 18, 1998 through November 13, 1998, and it focuses on the application of the siphon technology as a sub-component of the overall GeoSiphon Cell technology. [Q-TPL-T-00004

  7. Quantitative phase imaging for cell culture quality control.

    Science.gov (United States)

    Kastl, Lena; Isbach, Michael; Dirksen, Dieter; Schnekenburger, Jürgen; Kemper, Björn

    2017-05-01

    The potential of quantitative phase imaging (QPI) with digital holographic microscopy (DHM) for quantification of cell culture quality was explored. Label-free QPI of detached single cells in suspension was performed by Michelson interferometer-based self-interference DHM. Two pancreatic tumor cell lines were chosen as cellular model and analyzed for refractive index, volume, and dry mass under varying culture conditions. Firstly, adequate cell numbers for reliable statistics were identified. Then, to characterize the performance and reproducibility of the method, we compared results from independently repeated measurements and quantified the cellular response to osmolality changes of the cell culture medium. Finally, it was demonstrated that the evaluation of QPI images allows the extraction of absolute cell parameters which are related to cell layer confluence states. In summary, the results show that QPI enables label-free imaging cytometry, which provides novel complementary integral biophysical data sets for sophisticated quantification of cell culture quality with minimized sample preparation. © 2017 International Society for Advancement of Cytometry. © 2017 International Society for Advancement of Cytometry.

  8. Cell cycle phase influences tumour cell sensitivity to aminolaevulinic acid-induced photodynamic therapy in vitro.

    Science.gov (United States)

    Wyld, L.; Smith, O.; Lawry, J.; Reed, M. W.; Brown, N. J.

    1998-01-01

    Photodynamic therapy (PDT) is a form of cancer treatment based on the destruction of cells by the interaction of light, oxygen and a photosensitizer. Aminolaevulinic acid (ALA) is the prodrug of the photosensitizer protoporphyrin IX (PpIX). ALA-induced PDT depends on the rate of cellular synthesis of PpIX, which may vary with cell cycle phase. This study has investigated the relationship between cell cycle phase, PpIX generation and phototoxicity in synchronized and unsynchronized bladder cancer cells (HT1197). In unsynchronized cells, relative PpIX fluorescence values (arbitrary units) were significantly different between cell cycle phases after a 1-h ALA incubation (G1 24.8 +/- 0.7; S-phase, 32.7 +/- 0.8, P < 0.05; G2 35.4 +/- 0.8, P < 0.05). In synchronized cells after a 1-h ALA incubation, cells in G1 produced less PpIX than those in S-phase or G2 [6.65 +/- 1.1 ng per 10(5) cells compared with 15.5 +/- 2.1 (P < 0.05), and 8.1 +/- 1.8 ng per 10(5) cells (not significant) respectively] and were significantly less sensitive to ALA-induced PDT (% survival, G1 76.2 +/- 8.3; S-phase 49.7 +/- 4.6, P < 0.05; G2 44.2 +/- 2.4, P < 0.05). This differential response in tumour cells may have implications for clinical PDT, resulting in treatment resistance and possible failure in complete tumour response. PMID:9662250

  9. CENTRAL PLATEAU REMEDIATION OPTIMIZATION STUDY

    Energy Technology Data Exchange (ETDEWEB)

    BERGMAN, T. B.; STEFANSKI, L. D.; SEELEY, P. N.; ZINSLI, L. C.; CUSACK, L. J.

    2012-09-19

    THE CENTRAL PLATEAU REMEDIATION OPTIMIZATION STUDY WAS CONDUCTED TO DEVELOP AN OPTIMAL SEQUENCE OF REMEDIATION ACTIVITIES IMPLEMENTING THE CERCLA DECISION ON THE CENTRAL PLATEAU. THE STUDY DEFINES A SEQUENCE OF ACTIVITIES THAT RESULT IN AN EFFECTIVE USE OF RESOURCES FROM A STRATEGIC PERSPECTIVE WHEN CONSIDERING EQUIPMENT PROCUREMENT AND STAGING, WORKFORCE MOBILIZATION/DEMOBILIZATION, WORKFORCE LEVELING, WORKFORCE SKILL-MIX, AND OTHER REMEDIATION/DISPOSITION PROJECT EXECUTION PARAMETERS.

  10. Posterior bicondylar tibial plateau fractures.

    Science.gov (United States)

    Carlson, DuWayne A

    2005-02-01

    To present a case series of patients with posterior bicondylar tibial plateau fractures treated by direct fracture exposure and fixation through dual incisions. Retrospective clinical study. Level 1 trauma centers. Eight patients were identified that had posterior bicondylar tibial plateau fractures. Two patients had depressed posterolateral tibial plateau fractures with contained defects and did not have direct fracture exposure. One patient died of medical problems leaving 5 patients who underwent direct fracture exposure, reduction, and fixation. Posteromedial followed by posterolateral open reduction and internal fixation of posterior bicondylar tibial plateau fractures. At 6 to 24 months follow-up (mean 13 months), all patients returned to near full activities, each with aching after prolonged standing (8-hour shift). Range of motion averaged 2 degrees to 121 degrees of flexion. Three of 5 returned to manual labor jobs; the others were not employed at the time of injury. Posterior bicondylar tibial plateau fractures have a high association with lateral meniscal pathology and can be associated with anterior cruciate ligament injury. Reduction of the posterior plateau condyles is easiest with the knee in full extension. Flexion contractures can be a problem, and patients should be encouraged to regain/maintain knee extension. The dual-incision approach to these challenging fractures can result in good to excellent knee function for these patients.

  11. Cell cycle reentry from the late S phase: implications from stem cell formation in the moss Physcomitrella patens.

    Science.gov (United States)

    Ishikawa, Masaki; Hasebe, Mitsuyasu

    2015-05-01

    Differentiated cells are in a non-dividing, quiescent state, but some differentiated cells can reenter the cell cycle in response to appropriate stimuli. Quiescent cells are generally arrested at the G0/G1 phase, reenter the cell cycle, and progress to the S phase to replicate their genomic DNA. On the other hand, some types of cells are arrested at the different phase and reenter the cell cycle from there. In the moss Physcomitrella patens, the differentiated leaf cells of gametophores formed in the haploid generation contain approximately 2C DNA content, and DNA synthesis is necessary for reentry into the cell cycle, which is suggested to be arrested at late S phase. Here we review various cell-division reactivation processes in which cells reenter the cell cycle from the late S phase, and discuss possible mechanisms of such unusual cell cycle reentries with special emphasis on Physcomitrella.

  12. Hyperosmotic pressure on HEK 293 cells during the growth phase, but not the production phase, improves adenovirus production.

    Science.gov (United States)

    Shen, Chun Fang; Kamen, Amine

    2012-01-01

    Hyperosmotic stress has been widely explored as a means of improving specific antibody productivity in mammalian cell cultures. In contrast, a decrease in cell-specific productivity of adenovirus production has been reported in several studies in which virus production in HEK 293 cell cultures was conducted under hyperosmotic conditions. However, production of viral vectors and, in particular, adenoviral vectors is the result of two consecutive phases: the growth phase and the virus production phase. In this study, the singular and combined effects of osmolality on the phases of cell growth and virus production were evaluated in culture media with osmolalities ranging from 250 to 410mOsm. A two-factor, five-level full factorial design was used to investigate the effect of osmotic stress on cell physiology, as determined through the characterization of cell growth, cell metabolism, cell viability, cell cycle, cell RNA and total protein content, and total virus yield/cell-specific virus productivity. Overall, the results show that the growth of cells under hyperosmotic conditions induced favorable physiological states for viral production, and the specific virus productivity was improved by more than 11-fold when the medium's osmolality was increased from 250 to 410mOsm during the cell growth phase. Both hypo- and hyperosmotic stresses in the virus production phase reduced virus productivity by as much as a factor of six. Optimal virus productivity was achieved by growing cells in media with an osmolality of 370mOsm or greater, followed by a virus production phase at an osmolality of 290mOsm. Compared to standard culture and production conditions in isotonic media, the shift from high to low osmolality between the two phases resulted in a two- to three-fold increase in virus yields. This hyperosmotic pressure effect on virus productivity was reproduced in five different commercial serum-free media. Crown Copyright © 2011. Published by Elsevier B.V. All rights

  13. S-phase cells are more sensitive to high-linear energy transfer radiation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.; Naidu, M.; Liu, S.; Zhang, P.; Zhang, S.; Wang, H.; Wang, Y.

    2009-07-15

    S-phase cells are more resistant to low-linear energy transfer (LET) ionizing radiation (IR) than nonsynchronized and G{sub 1}-phase cells, because both nonhomologous end-joining (NHEJ) and homologous recombination repair can repair DNA double-strand breaks (DSBs) in the S phase. Although it was reported 3 decades ago that S-phase cells did not show more resistance to high-LET IR than cells in other phases, the mechanism remains unclear. We therefore attempted to study the phenotypes and elucidate the mechanism involved. Wild-type and NHEJ-deficient cell lines were synchronized using the double-thymidine approach. A clonogenic assay was used to detect the sensitivity of nonsynchronized, synchronized S-phase, and G{sub 2}-phase cells to high- and low-LET IR. The amounts of Ku bound to DSBs in the high- and low-LET-irradiated cells were also examined. S-phase wild-type cells (but not NHEJ-deficient cells) were more sensitive to high-LET IR than nonsynchronized and G{sub 2}-phase cells. In addition, S-phase wild-type cells showed less efficient Ku protein binding to DSBs than nonsynchronized and G{sub 2}-phase cells in response to high-LET IR, although all cells at all phases showed similarly efficient levels of Ku protein binding to DSBs in response to low-LET IR. S-phase cells are more sensitive to high-LET IR than nonsynchronized and G{sub 2}-phase cells, because of the following mechanism: it is more difficult for Ku protein to bind to high-LET IR-induced DNA DSBs in S-phase cells than in cells at other phases, which results in less efficient NHEJ.

  14. Protein microarrays using liquid phase fractionation of cell lysates.

    Science.gov (United States)

    Yan, Fang; Sreekumar, Arun; Laxman, Bharathi; Chinnaiyan, Arul M; Lubman, David M; Barder, Timothy J

    2003-07-01

    We describe an approach in which protein microarrays are produced using a two-dimensional (2-D) liquid phase fractionation of cell lysates. The method involves a pI-based fractionation using chromatofocusing in the first dimension followed by nonporous reversed-phase high-performance liquid chromatography (HPLC) of each pI fraction in the second dimension. This allows fractionation of cellular proteins in the liquid phase that could then be arrayed on nitrocellulose slides and used to study humoral response in cancer. Protein microarrays have been used to identify potential serum biomarkers for prostate cancer. It is shown that specific fractions are immunoreactive against prostate cancer serum but not against serum from healthy individuals. These proteins could serve as sero-diagnostic markers for prostate cancer. Importantly, this method allows for use of post-translationally modified proteins as baits for detection of humoral response. Proteins eliciting an immune response are identified using the molecular mass and peptide sequence data obtained using mass spectrometric analysis of the liquid fractions. The fractionation of proteins in the liquid phase make this method amenable to automation.

  15. Calcium-dependent plateau potentials in rostral ambiguus neurons in the newborn mouse brain stem in vitro

    DEFF Research Database (Denmark)

    Rekling, J C; Feldman, J L

    1997-01-01

    Calcium-dependent plateau potentials in rostral ambiguus neurons in the newborn mouse brain stem in vitro. J. Neurophysiol. 78: 2483-2492, 1997. The nucleus ambiguus contains vagal and glossopharyngeal motoneurons and preganglionic neurons involved in respiration, swallowing, vocalization......, and control of heart beat. Here we show that the rostral compact formation's ambiguus neurons, which control the esophageal phase of swallowing, display calcium-dependent plateau potentials in response to tetanic orthodromic stimulation or current injection. Whole cell recordings were made from visualized...... neurons in the rostral nucleus ambiguus using a slice preparation from the newborn mouse. Biocytin-labeling revealed dendritic trees with pronounced rostrocaudal orientations confined to the nucleus ambiguus, a morphological profile matching that of vagal motoneurons projecting to the esophagus. Single...

  16. Phase resetting reveals network dynamics underlying a bacterial cell cycle.

    Directory of Open Access Journals (Sweden)

    Yihan Lin

    Full Text Available Genomic and proteomic methods yield networks of biological regulatory interactions but do not provide direct insight into how those interactions are organized into functional modules, or how information flows from one module to another. In this work we introduce an approach that provides this complementary information and apply it to the bacterium Caulobacter crescentus, a paradigm for cell-cycle control. Operationally, we use an inducible promoter to express the essential transcriptional regulatory gene ctrA in a periodic, pulsed fashion. This chemical perturbation causes the population of cells to divide synchronously, and we use the resulting advance or delay of the division times of single cells to construct a phase resetting curve. We find that delay is strongly favored over advance. This finding is surprising since it does not follow from the temporal expression profile of CtrA and, in turn, simulations of existing network models. We propose a phenomenological model that suggests that the cell-cycle network comprises two distinct functional modules that oscillate autonomously and couple in a highly asymmetric fashion. These features collectively provide a new mechanism for tight temporal control of the cell cycle in C. crescentus. We discuss how the procedure can serve as the basis for a general approach for probing network dynamics, which we term chemical perturbation spectroscopy (CPS.

  17. Thermal dispersion and secondary crystallization of phase change memory cells

    Science.gov (United States)

    Deng, Y. F.; Li, Z.; Peng, J. H.; Liu, C.; Miao, X. S.

    2013-12-01

    The heat accumulation effect associated with heat dispersion process in phase change memory cell was analyzed. The pulse operating scheme was optimized. The pulse sequences with different intervals show distinct heat accumulation effect. A compact model with pulse sequence expansion was proposed, and the simulation result is close to the experiment data for a pulse sequence with interval 20 ns. The simulated R-V curves show that threshold voltage reduces with the decreasing pulse interval. The secondary crystallization and amorphization were used to explain the heat accumulation effect for high speed operation, cycling, and so on.

  18. Transition zone cells reach G2 phase before initiating elongation in maize root apex

    Directory of Open Access Journals (Sweden)

    M. Victoria Alarcón

    2017-06-01

    Full Text Available Root elongation requires cell divisions in the meristematic zone and cell elongation in the elongation zone. The boundary between dividing and elongating cells is called the transition zone. In the meristem zone, initial cells are continuously dividing, but on the basal side of the meristem cells exit the meristem through the transition zone and enter in the elongation zone, where they stop division and rapidly elongate. Throughout this journey cells are accompanied by changes in cell cycle progression. Flow cytometry analysis showed that meristematic cells are in cycle, but exit when they enter the elongation zone. In addition, the percentage of cells in G2 phase (4C strongly increased from the meristem to the elongation zone. However, we did not observe remarkable changes in the percentage of cells in cell cycle phases along the entire elongation zone. These results suggest that meristematic cells in maize root apex stop the cell cycle in G2 phase after leaving the meristem.

  19. Human Adipose Derived Stem Cells Induced Cell Apoptosis and S Phase Arrest in Bladder Tumor

    Directory of Open Access Journals (Sweden)

    Xi Yu

    2015-01-01

    Full Text Available The aim of this study was to determine the effect of human adipose derived stem cells (ADSCs on the viability and apoptosis of human bladder cancer cells. EJ and T24 cells were cocultured with ADSCs or cultured with conditioned medium of ADSCs (ADSC-CM, respectively. The cell counting and colony formation assay showed ADSCs inhibited the proliferation of EJ and T24 cells. Cell viability assessment revealed that the secretions of ADSCs, in the form of conditioned medium, were able to decrease cancer cell viability. Wound-healing assay suggested ADSC-CM suppressed migration of T24 and EJ cells. Moreover, the results of the flow cytometry indicated that ADSC-CM was capable of inducing apoptosis of T24 cells and inducing S phase cell cycle arrest. Western blot revealed ADSC-CM increased the expression of cleaved caspase-3 and cleaved PARP, indicating that ADSC-CM induced apoptosis in a caspase-dependent way. PTEN/PI3K/Akt pathway and Bcl-2 family proteins were involved in the mechanism of this reaction. Our study indicated that ADSCs may provide a promising and practicable manner for bladder tumor therapy.

  20. Chk1 prevents abnormal mitosis of S-phase HeLa cells containing DNA damage

    Institute of Scientific and Technical Information of China (English)

    LI XiaoFang; WARD Tarsha; YAO XueBiao; WU JiaRui

    2009-01-01

    To explore effects of DNA damage on cell-cycle progression in p53-deficient tumor cells,synchronized HeLa cells at G1,S and G2/M phases were treated with methyl methanesulfnate (MMS).The results showed that the MMS treatment resulted in the cell-cycle arrest or delay in all 3 phases,while the S-phase cells were the most sensitive to MMS.Further studies demonstrated that ATM-Chk2 and p38 MAPK signaling pathways were activated in all 3 phases when the cells were treated with MMS;whereas Chk1 was activated only in S phase under the drug treatment,indicating that Chk1 specifically participated in S-phase checkpoints.To analyze the role of Chk1 in S-phase checkpoints,we administered a specific Chk1 inhibitor,UCN-01,to the S-phase cells.The results showed that the S-phase cells treated with MMS+UCN-01 could enter aberrant mitosis without finishing DNA replication,indicating that Chk1 mainly functions in the DNA damage checkpoint rather than in the replication checkpoint.In addition,MMS treatment alone inhibited the accumulation of cyclin B1,a key component of M-phase CDK-cyclin complex,in the S-phase cells,whereas the inhibition of Chk1 activation resulted in the accumulation of cyclin B1 in the MMS-treated S-phase cells.This observation further supports the view that DNA-damaged S-phase cells enter abnormal mitosis when Chk1 activation is inhibited.Our results demonstrate that Chk1 is a specific kinase that plays an important role in the MMS-induced S-phase DNA damage checkpoint.As p53 is not involved in this process,Chk1 may be a potential target for p53-deficient tumor therapy.

  1. Industrialisation of polymer solar cells. Phase 2: Consolidation

    Energy Technology Data Exchange (ETDEWEB)

    Lauritzen, H.; Gevorgyan, S.; Frausig, J.; Andersen, Rasmus B.; Krebs, F.C.

    2013-03-15

    electrode. This entails more advantages; the energy-intensive vacuum processing is eliminated, the number of process steps is reduced, and the substrate that comes with the ITO-electrode is saved. Replacement of the ITO electrode also means independence from the scarce resource indium which will hinder advancement of the technology to its full potential. Also silver has proved a critical resource. An intense rise of the silver price has caused the production cost for standard ProcessOne to more than double over the project period. Due to this new processes are developed where silver is replaced by organic material. International research settings are currently reporting >11 % efficiency for small organic solar cells. It has proven difficult to obtain equivalent efficiency by roll-to-roll manufacturing and at the scale investigated in this project. An efficiency of 4.5 % has been attained but with a proprietary material. This material is, however, so expensive that it will never meet the project's cost target of 1 Euro/Wp of a cost-competitive polymer solar cell even if meet the 4.5 efficiency target. The standard active material, P3HT:PCBM, is judged the best choice considering economy, stability and roll-to-roll process ability. A production cost for was 5 Euro/Wp was reported for ProcessOne by the end of phase 1. Due to the steep rise in the silver price the production cost has now increased to 11 Euro/Wp. The more advanced processes addressed in this project has reduced the production cost to 4 - 6 Euro/Wp dependent on whether silver form part of it or not. With an anticipated effect of economy-of-scale for the purchased materials the production cost will be <1 Euro/Wp. (Author)

  2. Computational Methods for Estimation of Cell Cycle Phase Distributions of Yeast Cells

    Directory of Open Access Journals (Sweden)

    Jalovaara Henna

    2007-01-01

    Full Text Available Two computational methods for estimating the cell cycle phase distribution of a budding yeast (Saccharomyces cerevisiae cell population are presented. The first one is a nonparametric method that is based on the analysis of DNA content in the individual cells of the population. The DNA content is measured with a fluorescence-activated cell sorter (FACS. The second method is based on budding index analysis. An automated image analysis method is presented for the task of detecting the cells and buds. The proposed methods can be used to obtain quantitative information on the cell cycle phase distribution of a budding yeast S. cerevisiae population. They therefore provide a solid basis for obtaining the complementary information needed in deconvolution of gene expression data. As a case study, both methods are tested with data that were obtained in a time series experiment with S. cerevisiae. The details of the time series experiment as well as the image and FACS data obtained in the experiment can be found in the online additional material at http://www.cs.tut.fi/sgn/csb/yeastdistrib/.

  3. Integer quantum Hall effect in a triangular-lattice: Disorder effect and scaling behavior of the insulator-plateau transition

    Science.gov (United States)

    Yu, H. L.; Jiang, C.; Zhai, Z. Y.

    2017-01-01

    We investigate numerically the integer quantum Hall effect in a three-band triangular-lattice model. The three bands own the Chern number C=2,-1,-1, respectively. The lowest topological flat band carrying Chern number C=2, which leads to the Hall plateau σH = 2 (e2 / h) . This Hall plateau is sensitive to the disorder scattering and is rapidly destroyed by the weak disorder. Further increasing the strength of disorder, the gap of density of states always disappears before the vanishing of the corresponding Hall plateau. The scaling behavior of quantum phase transition between an insulator and a quantum Hall plateau is studied. We find that the insulator-plateau transition becomes sharper with increasing the size of system. Due to the different of edge states, the critical energy Ec1 gradually shifts to the center of Hall plateau while Ec2 is unaffected with increasing the disorder strength.

  4. Interfacial Tension Effect on Cell Partition in Aqueous Two-Phase Systems.

    Science.gov (United States)

    Atefi, Ehsan; Joshi, Ramila; Mann, Jay Adin; Tavana, Hossein

    2015-09-30

    Aqueous two-phase systems (ATPS) provide a mild environment for the partition and separation of cells. We report a combined experimental and theoretical study on the effect of interfacial tension of polymeric ATPS on the partitioning of cells between two phases and their interface. Two-phase systems are generated using polyethylene glycol and dextran of specific properties as phase-forming polymers and culture media as the solvent component. Ultralow interfacial tensions of the solutions are precisely measured using an axisymmetric drop shape analysis method. Partition experiments show that two-phase systems with an interfacial tension of 30 μJ/m(2) result in distribution of majority of cells to the bottom dextran phase. An increase in the interfacial tension results in a distribution of cells toward the interface. An independent cancer cell spheroid formation assay confirms these observations: a drop of the dextran phase containing cancer cells is dispensed into the immersion polyethylene glycol phase to form a cell-containing drop. Only at very small interfacial tensions do cells remain within the drop to aggregate into a spheroid. We perform a thermodynamic modeling of cell partition to determine variations of free energy associated with displacement of cells in ATPS with respect to the ultralow interfacial tensions. This modeling corroborates with the experimental results and demonstrates that at the smallest interfacial tension of 30 μJ/m(2), the free energy is a minimum with cells in the bottom phase. Increasing the interfacial tension shifts the minimum energy and partition of cells toward the interfacial region of the two aqueous phases. Examining differences in the partition behavior and minimum free energy modeling of A431.H9 cancer cells and mouse embryonic stem cells shows that the surface properties of cells further modulate partition in ATPS. This combined approach provides a fundamental understanding of interfacial tension role on cell partition in

  5. The Pajarito Plateau: a bibliography

    Science.gov (United States)

    Mathien, Frances Joan; Steen, Charlie R.; Allen, Craig D.

    1993-01-01

    This bibliography is the result of two initially independent projects. As the consulting archaeologist at Los Alamos National Laboratory (LANL), Charlie R. Steen collected entries at the suggestion of the staff of the Environmental Surveillance Group of the Health, Safety, and Environmental Division, HSE-8. The primary purpose was to aid the staff in evaluating cultural resources on LANL lands. In addition to works that related to the archaeology and history of the area, Steen included notations of a few books and articles in other fields such as geology and natural history. It was hoped that they also would be of value to other organizations and to students of past human activities on the Pajarito Plateau.At the same time, the National Park Service (NPS) was planning a major survey of Bandelier National Monument (BNM). As part of this plan, the author was asked to prepare a background document that described research previously carried out in the area, including an annotated bibliography. Although the survey would be limited to the park boundaries, the larger Pajarito Plateau is a more logical study area from physiographic, environmental, and cultural perspectives; hence the focus was on this larger region. Mathien (1986) also included some references to natural resources studies, particularly those initiated by NPS within Bandelier National Monument.Both bibliographies were made available to Colleen Olinger and Beverly Larson of the Health and Environmental Services Group at Los Alamos. They realized that while neither was complete, each included entries missing from the other. Larson suggested the two bibliographies be combined. (At this time, Craig Allen was studying the landscape of the Jemez Mountains [Allen 1984c, 1989]. His investigations included much detailed information on natural resource studies and were added in 1991 and 1992.)To limit the scope of their work, Steen and Mathien had chosen their parameter: the Pajarito Plateau. Geographically, the

  6. Monuments of the Giza Plateau

    Science.gov (United States)

    Ruggles, Clive L. N.

    The colossal pyramids of the pharaohs Khufu (Cheops), Khafre (Chephren), and Menkaure (Mycerinus) have attracted a huge amount of astronomical interest over the years, both scholarly and popular. Less attention is usually given to the broader context of structures on the Giza Plateau. One of the most notorious ideas connecting the Giza Plateau with astronomy is that the three large pyramids are laid out on the ground so as to reflect the appearance of the three stars of Orion's Belt in the sky. This idea is unsupportable for several reasons but has succeeded in generating huge public interest. Of much greater serious interest is the fact that the three main pyramids were oriented cardinally to extraordinary precision, which raises the questions of why this was important and how it was achieved. Another idea that has attracted serious attention but also some confusion is that the orientations of some narrow shafts within Khufu's pyramid might have been deliberately aligned upon particular stars. The overall layout of monuments on the plateau may certainly have been designed so as to emphasize certain solar phenomena, for symbolic and ideological reasons relating to a dominant sun cult. It is also possible that it formed part of a wider cosmological "master plan" extending to other pyramids and temples up to 20 km distant.

  7. 近50年气候变化对青藏高原牧草生产潜力及物候期的影响*%Impactofclimatechangeonpotentialproductivityandphenologicalphase offorageintheQinghai-TibetPlateauinthepast50years

    Institute of Scientific and Technical Information of China (English)

    赵雪雁; 万文玉; 王伟军

    2016-01-01

    roseduringthenearly50-yearperiod,increasingby0.53 ℃•(10a)-1.Precipitationgenerallyincreasedattherateof7.81 mm•(10a)-1, whilesunshinedurationdecreasedby16.94h•(10a)-1.PotentialclimateproductivityofforageintheQinghai-TibetPlateaupresentedanincreasingtrendfrom1965to2013,andspatialchangesoftheproductivity,inturn, increasedfromnorthwesttosoutheast. Then potential climate productivity of forage in the north andsouthintheplateausignificantlyincreasedandtherewaslessvariationintheeastoftheplateau.Furthermore,theregreening,heading and blossoming of forages advanced, while yellowing and withering delayed year after year, which extended theforagesphenologicalphases.Regreeningstageofforagedelayedfromsoutheasttonorthwest,althoughwitheringstageshowednoobviouschange.Underdrierandwarmerconditions,phenologicalperiodsofgrasslandvegetationintheregionbecameclosely related to climate change. Then precipitation and sunshine duration were negatively correlated with phenologicalperiodofthegrasslandvegetation.Temperaturewasthedominantconstraintonphenologicalphasesofgrasslandvegetationinthe study area. The study formed a relevant reference and basis for the protection of grassland ecosystems and enhancingpotentialclimateproductivityinQinghai-TibetPlateau.%基于青藏高原及周边107个气象站点1965—2013年逐月气温、降水及日照时数等气象数据,分析了1965年以来青藏高原区的气候变化趋势,并采用 MODIS 数据、ThornthwaiteMemorial 模型及 GIS 技术分析了近50 a 青藏高原牧草气候生产潜力及其时空变化特征;利用连续22 a 的青藏高原牧草生育期观测数据,探讨了牧草生育期的时空变化特征及气象因子与牧草主要发育期的关系。结果表明:1)近50a 青藏高原平均气温呈上升趋势,升温幅度达0.53

  8. Fast phase transitions induced by picosecond electrical pulses on phase change memory cells

    Science.gov (United States)

    Wang, W. J.; Shi, L. P.; Zhao, R.; Lim, K. G.; Lee, H. K.; Chong, T. C.; Wu, Y. H.

    2008-07-01

    The reversible and fast phase transitions induced by picosecond electrical pulses are observed in the nanostructured GeSbTe materials, which provide opportunities in the application of high speed nonvolatile random access memory devices. The mechanisms for fast phase transition are discussed based on the investigation of the correlation between phase transition speed and material size. With the shrinkage of material dimensions, the size effects play increasingly important roles in enabling the ultrafast phase transition under electrical activation. The understanding of how the size effects contribute to the phase transition speed is of great importance for ultrafast phenomena and applications.

  9. Applied catastrophic phase inversion: a continuous non-centrifugal phase separation step in biphasic whole-cell biocatalysis.

    Science.gov (United States)

    Glonke, Sebastian; Sadowski, Gabriele; Brandenbusch, Christoph

    2016-11-01

    Biphasic whole-cell biotransformations are known to be efficient alternatives to common chemical synthesis routes, especially for the production of, e.g. apolar enantiopure organic compounds. They provide high stereoselectivity combined with high product concentrations owing to the presence of an organic phase serving as substrate reservoir and product sink. Industrial implementation suffers from the formation of stable Pickering emulsions caused by the presence of cells. State-of-the-art downstream processing includes inefficient strategies such as excessive centrifugation, use of de-emulsifiers or thermal stress. In contrast, using the catastrophic phase inversion (CPI) phenomenon (sudden switch of emulsion type caused by addition of dispersed phase), Pickering-type emulsions can be destabilized efficiently. Within this work a model system using bis(2-ethylhexyl) phthalate (BEHP) as organic phase in combination with E. coli, JM101 was successfully separated using a continuous mixer settler setup. Compared to the state-of-the-art centrifugal separations, this process allows complete phase separation with no detectable water content or cells in the organic phase with no utilities/additives required. Furthermore, the concentration of the product is not affected by the separation. It is therefore a simple applicable method that can be used for separation of stable Pickering-type emulsions based on the knowledge of the point of inversion.

  10. Biodiversity and conservation in the Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The Tibetan Plateau (Qinghai-Xizang Plateau) is a unique biogeographic region in the world, where various landscapes, altitudinal belts, alpine ecosystems, and endangered and endemic species have been developed. A total of 26 altitudinal belts, 28 spectra of altitudinal belts, 12,000 species of vascular plant, 5,000 species of epiphytes, 210 species of mammals, and 532 species of birds have been recorded. The plateau is also one of the centers of species formation and differentiation in the world. To protect the biodiversity of the plateau, about 80 nature reserves have been designated, of which 45 are national or provincial, covering about 22% of the plateau area. Most of the nature reserves are distributed in the southeastern plateau. Recently, the Chinese government has initiated the "Natural Forests Protection Project of China,' mainly in the upper reaches of the Yangtze and Yellow rivers. "No logging" policies have been made and implemented for these areas.

  11. Growth Conditions and Cell Cycle Phase Modulate Phase Transition Temperatures in RBL-2H3 Derived Plasma Membrane Vesicles.

    Directory of Open Access Journals (Sweden)

    Erin M Gray

    Full Text Available Giant plasma membrane vesicle (GPMV isolated from a flask of RBL-2H3 cells appear uniform at physiological temperatures and contain coexisting liquid-ordered and liquid-disordered phases at low temperatures. While a single GPMV transitions between these two states at a well-defined temperature, there is significant vesicle-to-vesicle heterogeneity in a single preparation of cells, and average transition temperatures can vary significantly between preparations. In this study, we explore how GPMV transition temperatures depend on growth conditions, and find that average transition temperatures are negatively correlated with average cell density over 15°C in transition temperature and nearly three orders of magnitude in average surface density. In addition, average transition temperatures are reduced by close to 10°C when GPMVs are isolated from cells starved of serum overnight, and elevated transition temperatures are restored when serum-starved cells are incubated in serum-containing media for 12 h. We also investigated variation in transition temperature of GPMVs isolated from cells synchronized at the G1/S border through a double Thymidine block and find that average transition temperatures are systematically higher in GPMVs produced from G1 or M phase cells than in GPMVs prepared from S or G1 phase cells. Reduced miscibility transition temperatures are also observed in GPMVs prepared from cells treated with TRAIL to induce apoptosis or sphingomyelinase, and in some cases a gel phase is observed at temperatures above the miscibility transition in these vesicles. We conclude that at least some variability in GPMV transition temperature arises from variation in the local density of cells and asynchrony of the cell cycle. It is hypothesized that GPMV transition temperatures are a proxy for the magnitude of lipid-mediated membrane heterogeneity in intact cell plasma membranes at growth temperatures. If so, these results suggest that cells tune

  12. Ni coarsening in the three-phase solid oxide fuel cell anode - a phase-field simulation study

    CERN Document Server

    Chen, Hsun-Yi; Cronin, J Scott; Wilson, James R; Barnett, Scott A; Thornton, Katsuyo

    2012-01-01

    Ni coarsening in Ni-yttria stabilized zirconia (YSZ) solid oxide fuel cell anodes is considered a major reason for anode degradation. We present a predictive, quantative modeling framework based on the phase-field approach to systematically examine coarsening kinetics in such anodes. The initial structures for simulations are experimentally acquired functional layers of anodes. Sample size effects and error analysis of contact angles are examined. Three phase boundary (TPB) lengths and Ni surface areas are quantatively identified on the basis of the active, dead-end, and isolated phase clusters throughout coarsening. Tortuosity evolution of the pores is also investigated. We find that phase clusters with larger characteristic length evolve slower than those with smaller length scales. As a result, coarsening has small positive effects on transport, and impacts less on the active Ni surface area than the total counter part. TPBs, however, are found to be sensitive to local morphological features and are only i...

  13. Observation of the Zero Hall Plateau in a Quantum Anomalous Hall Insulator

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Yang; Feng, Xiao; Ou, Yunbo; Wang, Jing; Liu, Chang; Zhang, Liguo; Zhao, Dongyang; Jiang, Gaoyuan; Zhang, Shou-Cheng; He, Ke; Ma, Xucun; Xue, Qi-Kun; Wang, Yayu

    2015-09-16

    We report experimental investigations on the quantum phase transition between the two opposite Hall plateaus of a quantum anomalous Hall insulator. We observe a well-defined plateau with zero Hall conductivity over a range of magnetic field around coercivity when the magnetization reverses. The features of the zero Hall plateau are shown to be closely related to that of the quantum anomalous Hall effect, but its temperature evolution exhibits a significant difference from the network model for a conventional quantum Hall plateau transition. We propose that the chiral edge states residing at the magnetic domain boundaries, which are unique to a quantum anomalous Hall insulator, are responsible for the novel features of the zero Hall plateau.

  14. Screening ToxCast™ Phase I Chemicals in a Mouse Embryonic Stem Cell Adherent Cell Differentiation and Cytotoxicity (ACDC) Assay

    Science.gov (United States)

    An Adherent Cell Differentiation and Cytotoxicity (ACDC) in vitro assay with mouse embryonic stem cells was used to screen the ToxCast Phase I chemical library for effects on cellular differentiation and cell number. The U.S. Environmental Protection Agency (EPA) established the ...

  15. Therapeutic dendritic cell vaccination of patients with metastatic renal cell carcinoma - A clinical, phase 1/2 trial

    DEFF Research Database (Denmark)

    Berntsen, A.; Trepiakas, R.; Wenandy, L.;

    2008-01-01

    Therapeutic dendritic cell (DC) vaccination against cancer is a strategy aimed at activating the immune system to recognize and destroy tumor cells. In this nonrandomized phase 1/2 trial, we investigated the safety, feasibility, induction of T-cell response, and clinical response after treatment...

  16. Exploration in Newnes Plateau, NSW

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, P.; McQuade, C. [Pasminco Port Pirie Smelter, NSW (Australia)

    1999-06-01

    Underground coal mining operations in the Western Coalfields of NSW extend into the Newnes Plateau area. The Newnes Plateau area is known for its floral diversity and distinctive topography. A quantitative flora assessment concerning rehabilitation performance of exploration sites was undertaken to refine the environmental component of the exploration process and identify practices that may assist in an improved rate of regeneration within disturbed areas. This article briefly summarises the method and key outcomes of the study, undertaken as part of an Honours Degree program. Surveys of sites showed that plant height was reduced due to vehicle traffic compacting soil, and this also led to a reduced number of plant species and a reduced number of seedlings germinating. Percentage litter cover was found to be positively correlated with the number of species on the sites and the percent plant cover of the regenerating vegetation, shallow surface ripping is recommended to relieve soil compaction. Seeds should be collected from exploration sites prior to disturbance, particularly of species like Banksia and Haken that retain their seed on the plant. Seed should then be dispersed after work has finished. 1 fig., 2 photos.

  17. Novel Elastomeric Closed Cell Foam - Nonwoven Fabric Composite Material (Phase III)

    Science.gov (United States)

    2008-10-01

    AFRL-RX-TY-TR-2009-4577 NOVEL ELASTOMERIC CLOSED CELL FOAM – NONWOVEN FABRIC COMPOSITE MATERIAL (PHASE III) Davis, Stephen C...07-OCT-2009 Novel Elastomeric Closed Cell Foam - Nonwoven Fabric Composite Material (Phase III) FA4819-07-D-0001 62102F 4347 D2 4347D23A Davis...develop novel closed cell foam- nonwoven fabric composites to commercial scale evaluation. Armacell tasks focused on foam optimization for commercial

  18. Spatial phase sensitivity of complex cells in primary visual cortex depends on stimulus contrast.

    Science.gov (United States)

    Meffin, H; Hietanen, M A; Cloherty, S L; Ibbotson, M R

    2015-12-01

    Neurons in primary visual cortex are classified as simple, which are phase sensitive, or complex, which are significantly less phase sensitive. Previously, we have used drifting gratings to show that the phase sensitivity of complex cells increases at low contrast and after contrast adaptation while that of simple cells remains the same at all contrasts (Cloherty SL, Ibbotson MR. J Neurophysiol 113: 434-444, 2015; Crowder NA, van Kleef J, Dreher B, Ibbotson MR. J Neurophysiol 98: 1155-1166, 2007; van Kleef JP, Cloherty SL, Ibbotson MR. J Physiol 588: 3457-3470, 2010). However, drifting gratings confound the influence of spatial and temporal summation, so here we have stimulated complex cells with gratings that are spatially stationary but continuously reverse the polarity of the contrast over time (contrast-reversing gratings). By varying the spatial phase and contrast of the gratings we aimed to establish whether the contrast-dependent phase sensitivity of complex cells results from changes in spatial or temporal processing or both. We found that most of the increase in phase sensitivity at low contrasts could be attributed to changes in the spatial phase sensitivities of complex cells. However, at low contrasts the complex cells did not develop the spatiotemporal response characteristics of simple cells, in which paired response peaks occur 180° out of phase in time and space. Complex cells that increased their spatial phase sensitivity at low contrasts were significantly overrepresented in the supragranular layers of cortex. We conclude that complex cells in supragranular layers of cat cortex have dynamic spatial summation properties and that the mechanisms underlying complex cell receptive fields differ between cortical layers.

  19. Staphylococcus aureus Lpl Lipoproteins Delay G2/M Phase Transition in HeLa Cells.

    Science.gov (United States)

    Nguyen, Minh-Thu; Deplanche, Martine; Nega, Mulugeta; Le Loir, Yves; Peisl, Loulou; Götz, Friedrich; Berkova, Nadia

    2016-01-01

    The cell cycle is an ordered set of events, leading to cell growth and division into two daughter cells. The eukaryotic cell cycle consists of interphase (G1, S, and G2 phases), followed by the mitotic phase and G0 phase. Many bacterial pathogens secrete cyclomodulins that interfere with the host cell cycle. In Staphylococcus aureus four cyclomodulins have been described so far that all represent toxins and are secreted into the culture supernatant. Here we show that the membrane-anchored lipoprotein-like proteins (Lpl), encoded on a genomic island called νSaα, interact with the cell cycle of HeLa cells. By comparing wild type and lpl deletion mutant it turned out that the lpl cluster is causative for the G2/M phase transition delay and also contributes to increased invasion frequency. The lipoprotein Lpl1, a representative of the lpl cluster, also caused G2/M phase transition delay. Interestingly, the lipid modification, which is essential for TLR2 signaling and activation of the immune system, is not necessary for cyclomodulin activity. Unlike the other staphylococcal cyclomodulins Lpl1 shows no cytotoxicity even at high concentrations. As all Lpl proteins are highly conserved there might be a common function that is accentuated by their multiplicity in a tandem gene cluster. The cell surface localized Lpls' suggests a correlation between G2/M phase transition delay and host cell invasion.

  20. Staphylococcus aureus Lpl Lipoproteins Delay G2/M Phase Transition in HeLa Cells

    Science.gov (United States)

    Nguyen, Minh-Thu; Deplanche, Martine; Nega, Mulugeta; Le Loir, Yves; Peisl, Loulou; Götz, Friedrich; Berkova, Nadia

    2016-01-01

    The cell cycle is an ordered set of events, leading to cell growth and division into two daughter cells. The eukaryotic cell cycle consists of interphase (G1, S, and G2 phases), followed by the mitotic phase and G0 phase. Many bacterial pathogens secrete cyclomodulins that interfere with the host cell cycle. In Staphylococcus aureus four cyclomodulins have been described so far that all represent toxins and are secreted into the culture supernatant. Here we show that the membrane-anchored lipoprotein-like proteins (Lpl), encoded on a genomic island called νSaα, interact with the cell cycle of HeLa cells. By comparing wild type and lpl deletion mutant it turned out that the lpl cluster is causative for the G2/M phase transition delay and also contributes to increased invasion frequency. The lipoprotein Lpl1, a representative of the lpl cluster, also caused G2/M phase transition delay. Interestingly, the lipid modification, which is essential for TLR2 signaling and activation of the immune system, is not necessary for cyclomodulin activity. Unlike the other staphylococcal cyclomodulins Lpl1 shows no cytotoxicity even at high concentrations. As all Lpl proteins are highly conserved there might be a common function that is accentuated by their multiplicity in a tandem gene cluster. The cell surface localized Lpls' suggests a correlation between G2/M phase transition delay and host cell invasion. PMID:28083519

  1. Cell cycle phase expansion in nitrogen-limited cultures of Saccharomyces cerevisiae

    OpenAIRE

    1980-01-01

    The time and coordination of cell cycle events were examined in the budding yeast Saccharomyces cerevisiae. Whole-cell autoradiographic techniques and time-lapse photography were used to measure the duration of the S, G1, and G2 phases, and the cell cycle positions of "start" and bud emergence, in cells whose growth rates were determined by the source of nitrogen. It was observed that the G1, S, and G2 phases underwent a proportional expansion with increasing cell cycle length, with the S pha...

  2. Computerized video time-lapse (CVTL) analysis of cell death kinetics in human bladder carcinoma cells (EJ30) X-irradiated in different phases of the cell cycle.

    Science.gov (United States)

    Chu, Kenneth; Leonhardt, Edith A; Trinh, Maxine; Prieur-Carrillo, Geraldine; Lindqvist, Johan; Albright, Norman; Ling, C Clifton; Dewey, William C

    2002-12-01

    The purpose of this study was to quantify the modes and kinetics of cell death for EJ30 human bladder carcinoma cells irradiated in different phases of the cell cycle. Asynchronous human bladder carcinoma cells were observed in multiple fields by computerized video time-lapse (CVTL) microscopy for one to two cell divisions before irradiation (6 Gy) and for 6-11 days afterward. By analyzing time-lapse movies collected from these fields, pedigrees were constructed showing the behaviors of 231 cells irradiated in different phases of the cell cycle (i.e. at different times after mitosis). A total of 219 irradiated cells were determined to be non-colony-forming over the time spans of the experiments. In these nonclonogenic pedigrees, cells died primarily by necrosis either without entering mitosis or over 1 to 10 postirradiation generations. A total of 105 giant cells developed from the irradiated cells or their progeny, and 30% (31/105) divided successfully. Most nonclonogenic cells irradiated in mid-S phase (9-12 h after mitosis) died by the second generation, while those irradiated either before or after this short period in mid-S phase had cell deaths occurring over one to nine postirradiation generations. The nonclonogenic cells irradiated in mid-S phase also experienced the longest average delay before their first division. Clonogenic cells (11/12 cells) divided sooner after irradiation than the average nonclonogenic cells derived from the same phase of the cell cycle. The early death and long division delay observed for nonclonogenic cells irradiated in mid-S phase could possibly result from an increase in damage induced during the transition from the replication of euchromatin to the replication of heterochromatin.

  3. Characterization Method for 3D Substructure of Nuclear Cell Based on Orthogonal Phase Images

    Directory of Open Access Journals (Sweden)

    Ying Ji

    2015-01-01

    Full Text Available A set of optical models associated with blood cells are introduced in this paper. All of these models are made up of different parts possessing symmetries. The wrapped phase images as well as the unwrapped ones from two orthogonal directions related to some of these models are obtained by simulation technique. Because the phase mutation occurs on the boundary between nucleus and cytoplasm as well as on the boundary between cytoplasm and environment medium, the equation of inflexion curve is introduced to describe the size, morphology, and substructure of the nuclear cell based on the analysis of the phase features of the model. Furthermore, a mononuclear cell model is discussed as an example to verify this method. The simulation result shows that characterization with inflexion curve based on orthogonal phase images could describe the substructure of the cells availably, which may provide a new way to identify the typical biological cells quickly without scanning.

  4. Prehistoric human settling on the Tibetan Plateau

    Science.gov (United States)

    Chen, Fahu; Zhang, Dongju; Dong, Guanghui

    2017-04-01

    When and where did human first settle down on the Tibetan Plateau is under hot debate among archaeologist, anthropologists, geneticist and paleo-geographers. Based on systematic archaeological, chronological and archaeo-botanical studies of 53 sites in Northeastern Tibetan Plateau, we propose that agriculture facilitated human permanent settlement on the Tibetan Plateau initially since 5200 years ago below 2500 masl and since 3600 years ago up to around 4000 masl, possibly assisted by domesticated animals (Chen et al. 2015). By studying hand- and footprints in Chusang, Meyer et al. (2016) argue that hunter-gatherers permanently occupied central Tibetan Plateau in early Holocene without the help of agriculture. However, we think the limited hand- and footprints evidence found in Chusang could indicate no more than prehistoric hunter-gatherers presence on the remote central Tibetan Plateau in the early Holocene. In addition, by reviewing all the published archaeological data, we propose that human migrated to the Tibetan Plateau from the last Deglacial period to late Holocene mainly from North China via Yellow River valley and its tributary valleys in the Northeastern Tibetan Plateau (NETP). This migration is constituted of four stages (Upper Paleolithic, Epi-Paleolithic, Neolithic and Bronze Age) when human adapted to the high altitude environment and climate change with different strategies and techniques. Particularly, the prevail of microlithic technology in North China provoked hunter-gatherers' first visit to the NETP in relatively ameliorated last Deglacial period, and the the quick development of millet farming and subsequent mixed barley-wheat farming and sheep herding facilitated farmers and herders permanently settled in Tibetan Plateau, even above 3000 masl, during mid- and late Holocene. References: Chen et al., 2015. Agriculture facilitated permanent human occupation of the Tibetan Plateau after 3600 BP. Science, 347: 248-250. Meyer et al., 2016

  5. Pentostatin in T-cell malignancies - a phase II trial of the EORTC

    NARCIS (Netherlands)

    Ho, AD; Suciu, S; Stryckmans, P; De Cataldo, F; Willemze, R; Thaler, J; Peetermans, M; Dohner, H; Solbu, G; Dardenne, M; Zittoun, R

    1999-01-01

    Purpose: Within this phase II EORTC trial, we have investigated the safety and efficacy of pentostatin in lymphoid malignancies. We have previously reported the results in T- and B-cell prolymphocytic leukemia, B-cell chronic lymphocytic leukemia (B-CLL) and hairy cell leukemia. This report focuses

  6. Pentostatin in T-cell malignancies - a phase II trial of the EORTC

    NARCIS (Netherlands)

    Ho, AD; Suciu, S; Stryckmans, P; De Cataldo, F; Willemze, R; Thaler, J; Peetermans, M; Dohner, H; Solbu, G; Dardenne, M; Zittoun, R

    1999-01-01

    Purpose: Within this phase II EORTC trial, we have investigated the safety and efficacy of pentostatin in lymphoid malignancies. We have previously reported the results in T- and B-cell prolymphocytic leukemia, B-cell chronic lymphocytic leukemia (B-CLL) and hairy cell leukemia. This report focuses

  7. Isolation of quiescent and nonquiescent cells from yeast stationary-phase cultures

    NARCIS (Netherlands)

    Allen, Chris; Büttner, Sabrina; Aragon, Anthony D.; Thomas, Jason A.; Meirelles, Osorio; Jaetao, Jason E.; Benn, Don; Ruby, Stephanie W.; Veenhuis, Marten; Madeo, Frank; Werner-Washburne, Margaret

    2006-01-01

    Quiescence is the most common and, arguably, most poorly understood cell cycle state. This is in part because pure populations of quiescent cells are typically difficult to isolate. We report the isolation and characterization of quiescent and nonquiescent cells from stationary-phase (SP) yeast

  8. Technology development for phosphoric acid fuel cell powerplant, phase 2

    Science.gov (United States)

    Christner, L.

    1981-01-01

    The development of materials, cell components, and reformers for on site integrated energy systems is described. Progress includes: (1) heat-treatment of 25 sq cm, 350 sq cm and 1200 sq cm cell test hardware was accomplished. Performance of fuel cells is improved by using this material; (2) electrochemical and chemical corrosion rates of heat-treated and as-molded graphite/phenolic resin composites in phosphoric acid were determined; (3) three cell, 5 in. x 15 in. stacks operated for up to 10,000 hours and 12 in. x 17 in. five cell stacks were tested for 5,000 hours; (4) a three cell 5 in. x 15 in. stack with 0.12 mg Pt/sq cm anodes and 0.25 mg Pt/sq cm cathodes was operated for 4,500 hours; and (5) an ERC proprietary high bubble pressure matrix, MAT-1, was tested for up to 10,000 hours.

  9. Technology development for phosphoric acid fuel cell powerplant (phase 2)

    Science.gov (United States)

    Christner, L.

    1979-01-01

    The status of technology for the manufacturing and testing of 1200 sq. cm cell materials, components, and stacks for on-site integrated energy systems is assessed. Topics covered include: (1) preparation of thin layers of silicon carbide; (2) definition and control schemes for volume changes in phosphoric acid fuel cells; (3) preparation of low resin content graphite phenolic resin composites; (4) chemical corrosion of graphite-phenolic resin composites in hot phosphoric acid; (5) analysis of electrical resistance of composite materials for fuel cells; and (6) fuel cell performance and testing.

  10. K562 cells display different vulnerability to H₂O₂ induced oxidative stress in differing cell cycle phases.

    Science.gov (United States)

    Akcakaya, Handan; Dal, Fulya; Tok, Sabiha; Cinar, Suzan-Adin; Nurten, Rustem

    2015-02-01

    Oxidative stress can be defined as the increase of oxidizing agents like reactive oxygen and nitrogen species, or the imbalance between the antioxidative defense mechanism and oxidants. Cell cycle checkpoint response can be defined as the arrest of the cell cycle functioning after damaging chemical exposure. This temporary arrest may be a period of time given to the cells to repair the DNA damage before entering the cycle again and completing mitosis. In order to determine the effects of oxidative stress on several cell cycle phases, human erytroleukemia cell line (K562) was synchronized with mimosine and genistein, and cell cycle analysis carried out. Synchronized cells were exposed to oxidative stress with hydrogen peroxide (H2O2) at several concentrations and different times. Changes on mitochondria membrane potential (ΔΨm) of K562 cells were analyzed in G1, S, and G2 /M using Rhodamine 123 (Rho 123). To determine apoptosis and necrosis, stressed cells were stained with Annexin V (AnnV) and propidium iodide (PI) for flow cytometry. Changes were observed in the ΔΨm of synchronized and asynchronized cells that were exposed to oxidative stress. Synchronized cells in S phase proved resistant to the effects of oxidative stress and synchronized cells at G2 /M phase were sensitive to the effects of H2O2 -induced oxidative stress at 500 μM and above.

  11. Fuel cell power systems for remote applications. Phase 1 final report and business plan

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-02-01

    The goal of the Fuel Cell Power Systems for Remote Applications project is to commercialize a 0.1--5 kW integrated fuel cell power system (FCPS). The project targets high value niche markets, including natural gas and oil pipelines, off-grid homes, yachts, telecommunication stations and recreational vehicles. Phase 1 includes the market research, technical and financial analysis of the fuel cell power system, technical and financial requirements to establish manufacturing capability, the business plan, and teaming arrangements. Phase 1 also includes project planning, scope of work, and budgets for Phases 2--4. The project is a cooperative effort of Teledyne Brown Engineering--Energy Systems, Schatz Energy Research Center, Hydrogen Burner Technology, and the City of Palm Desert. Phases 2 through 4 are designed to utilize the results of Phase 1, to further the commercial potential of the fuel cell power system. Phase 2 focuses on research and development of the reformer and fuel cell and is divided into three related, but potentially separate tasks. Budgets and timelines for Phase 2 can be found in section 4 of this report. Phase 2 includes: Task A--Develop a reformate tolerant fuel cell stack and 5 kW reformer; Task B--Assemble and deliver a fuel cell that operates on pure hydrogen to the University of Alaska or another site in Alaska; Task C--Provide support and training to the University of Alaska in the setting up and operating a fuel cell test lab. The Phase 1 research examined the market for power systems for off-grid homes, yachts, telecommunication stations and recreational vehicles. Also included in this report are summaries of the previously conducted market reports that examined power needs for remote locations along natural gas and oil pipelines. A list of highlights from the research can be found in the executive summary of the business plan.

  12. Animal-cell culture in aqueous two-phase systems.

    NARCIS (Netherlands)

    Zijlstra, G.M.

    1998-01-01

    In current industrial biotechnology, animal-cell culture is an important source of therapeutic protein products. The conventional animal-cell production processes, however, include many unit operations as part of the fermentation and downstream processing strategy. The research described in this the

  13. Phase-separated chitosan-fibrin microbeads for cell delivery.

    Science.gov (United States)

    Chen, Zhewei; Wang, Limin; Stegemann, Jan P

    2011-01-01

    Matrix-enhanced delivery of cells is a promising approach to improving current cell therapies. Our objective was to create cell-laden composite microbeads that combine the attractive features of the natural polymers chitosan and fibrin. Liquid polydimethylsiloxane was used to emulsify a chitosan-fibrinogen solution containing suspended human fibroblast cells, followed by initiation of thrombin-mediated polymerization of fibrin and thermal/pH-mediated gelation of chitosan. Chitosan/fibrin weight percent (wt%) ratios of 100/0, 75/25, 50/50 and 25/75 were investigated. Microbead diameters ranged from 275 ± 99 µm to 38 ± 10 µm using impeller speeds from 600 to 1400 rpm. Fibroblasts remained viable on day 1 post-fabrication in all matrices, but cell viability was markedly higher in high-fibrin microbeads by day 8 post-fabrication. Cell spreading and interaction with the extracellular matrix was also markedly increased in high-fibrin matrices. Such composite microbeads containing viable entrapped cells have potential for minimally invasive delivery of cells for a variety of tissue repair applications.

  14. Animal-cell culture in aqueous two-phase systems

    NARCIS (Netherlands)

    Zijlstra, G.M.

    1998-01-01

    In current industrial biotechnology, animal-cell culture is an important source of therapeutic protein products. The conventional animal-cell production processes, however, include many unit operations as part of the fermentation and downstream processing strategy. The research described in

  15. Photovoltaic Cell Fed 3-Phase Induction Motor Using MPPT Technique

    Directory of Open Access Journals (Sweden)

    Gudimetla Ramesh

    2014-10-01

    Full Text Available This Paper emphasizes on proposing a cost effective photovoltaic (PV fed 3 phase Induction motor drive which serves for rural pumping applications. Generally in a standalone system, the PV unit will charge the battery and the battery set up in turn will serve as a source for the inverter. A new single stage battery less power conversion is employed by designing a maximum power point tracker (MPPT embedded boost converter which makes the overall cost of the setup to go down considerably. The realized as a prototype consisting PV array of 500watts, MPPT aided boost converter, three phase inverter and a three phase squirrel cage induction drive of 300 watts. An efficient and low cost micro controller dspic4011 is used a platform to code and implement the prominent perturb and observe MPPT technique .Sinusoidal pulse width modulation (SPWM is the  control technique employed for  the three phase  inverter. To validate the experimental results simulation of the whole set up is carried out in matlab /simulink environment. Simulation and hardware results reveal that the system is versatile.

  16. Quantitative photothermal phase imaging of red blood cells using digital holographic photothermal microscope.

    Science.gov (United States)

    Vasudevan, Srivathsan; Chen, George C K; Lin, Zhiping; Ng, Beng Koon

    2015-05-10

    Photothermal microscopy (PTM), a noninvasive pump-probe high-resolution microscopy, has been applied as a bioimaging tool in many biomedical studies. PTM utilizes a conventional phase contrast microscope to obtain highly resolved photothermal images. However, phase information cannot be extracted from these photothermal images, as they are not quantitative. Moreover, the problem of halos inherent in conventional phase contrast microscopy needs to be tackled. Hence, a digital holographic photothermal microscopy technique is proposed as a solution to obtain quantitative phase images. The proposed technique is demonstrated by extracting phase values of red blood cells from their photothermal images. These phase values can potentially be used to determine the temperature distribution of the photothermal images, which is an important study in live cell monitoring applications.

  17. Critical kinetic control of non-stoichiometric intermediate phase transformation for efficient perovskite solar cells

    Science.gov (United States)

    Rong, Yaoguang; Venkatesan, Swaminathan; Guo, Rui; Wang, Yanan; Bao, Jiming; Li, Wenzhi; Fan, Zhiyong; Yao, Yan

    2016-06-01

    Organometal trihalide perovskites (OTP) have attracted significant attention as a low-cost and high-efficiency solar cell material. Due to the strong coordination between lead iodide (PbI2) and dimethyl sulfoxide (DMSO) solvent, a non-stoichiometric intermediate phase of MA2Pb3I8(DMSO)2 (MA = CH3NH3+) usually forms in the one-step deposition method that plays a critical role in attaining high power conversion efficiency. However, the kinetic understanding of how the non-stoichiometric intermediate phase transforms during thermal annealing is currently absent. In this work, we investigated such a phase transformation and provided a clear picture of three phase transition pathways as a function of annealing conditions. The interdiffusion of MAI and DMSO varies strongly with the annealing temperature and time, thus determining the final film composition and morphology. A surprising finding reveals that the best performing cells contain ~18% of the non-stoichiometric intermediate phase, instead of pure phase OTP. The presence of such an intermediate phase enables smooth surface morphology and enhances the charge carrier lifetime. Our results highlight the importance of the intermediate phase growth kinetics that could lead to large-scale production of efficient solution processed perovskite solar cells.Organometal trihalide perovskites (OTP) have attracted significant attention as a low-cost and high-efficiency solar cell material. Due to the strong coordination between lead iodide (PbI2) and dimethyl sulfoxide (DMSO) solvent, a non-stoichiometric intermediate phase of MA2Pb3I8(DMSO)2 (MA = CH3NH3+) usually forms in the one-step deposition method that plays a critical role in attaining high power conversion efficiency. However, the kinetic understanding of how the non-stoichiometric intermediate phase transforms during thermal annealing is currently absent. In this work, we investigated such a phase transformation and provided a clear picture of three phase transition

  18. Compressive Tectonics around Tibetan Plateau Edges

    Institute of Scientific and Technical Information of China (English)

    Zhao Zhixin; Xu Jiren

    2009-01-01

    Various earthquake fault types, mechanism solutions, stress field, and other geophysical data were analyzed for study on the crust movement in the Tibetan plateau and its tectonic implications. The results show that numbers of thrust fault and strike-slip fault type earthquakes with strong compressive stress near NNE-SSW direction occurred in the edges around the plateau except the eastern boundary. Some normal faulting type earthquakes concentrate in the Central Tibetan plateau. The strikes of fault planes of thrust and strike-slip faulting earthquakes are almost in the E-W direction based on the analyses of the Wulff stereonet diagrams of fault plane solutions. This implies that the dislocation slip vectors of the thrust and strike-slip faulting type events have quite great components in the N-S direction. The compression motion mainly probably plays the tectonic active regime around the plateau edges. The compressive stress in N-S or NE-SW directions predominates earthquake occurrence in the thrust and strike-slip faulting event region around the plateau. The compressive motion around the Tibetan plateau edge is attributable to the northward motion of the Indian subcontinent plate. The northward motion of the Tibetan plateau shortened in the N-S direction encounters probably strong obstructions at the western and northern margins.

  19. Long-term exhumation history of the Inner Mongolian Plateau constrained by apatite fission track analysis

    Science.gov (United States)

    Li, Ke; Jolivet, Marc; Zhang, Zhicheng; Li, Jianfeng; Tang, Wenhao

    2016-01-01

    The Inner Mongolian Plateau, along the southeastern flank of the wider Mongolian Plateau, is a vast undulating surface ranging in elevation between 900 and 1500 m above sea level. The peculiar topography of this area is assumed to be closely related to its complex tectono-thermal evolution since Late Paleozoic. The lithospheric structure of the Plateau includes three continental blocks: the Mandula and the Bart Obo blocks form the southern margin of the Central Asian Orogenic Belt in that area, and to the south, the Plateau includes the northern margin of the North China Craton. Apatite fission track (AFT) ages and track length distributions from 13 basement outcrops situated in the main tectonic blocks forming the Inner Mongolian Plateau were determined in order to reconstruct its denudation history. The thermal histories inferred from these data imply multi-phased, differential exhumation/burying processes from the Late Paleozoic to the Early Cretaceous. This complex thermal history is largely related to the Early/Middle Triassic closure of the Paleo-Asian Ocean, the Jurassic closure of the Mongol-Okhotsk Ocean, and the Early Cretaceous orogenic collapse of the Mongol-Okhotsk belt. Finally, since Late Cretaceous, no further major tectonic movement occurred and the Inner Mongolian Plateau has been largely peneplained.

  20. Transcriptional Characterization of Salmonella TAl00 in Growth and Stationary Phase: Mutagenesis of MX in Both Types of Cells

    Science.gov (United States)

    The Salmonella (Ames) mutagenicity assay can be performed using cells that are in different growth phases. Thus, the plate-incorporation assay involves plating stationary-phase cells with the mutagen, after which the cells undergo a brief lag phase and, consequently, are exposed ...

  1. Approaches to myosin modelling in a two-phase flow model for cell motility

    Science.gov (United States)

    Kimpton, L. S.; Whiteley, J. P.; Waters, S. L.; Oliver, J. M.

    2016-04-01

    A wide range of biological processes rely on the ability of cells to move through their environment. Mathematical models have been developed to improve our understanding of how cells achieve motion. Here we develop models that explicitly track the cell's distribution of myosin within a two-phase flow framework. Myosin is a small motor protein which is important for contracting the cell's actin cytoskeleton and enabling cell motion. The two phases represent the actin network and the cytosol in the cell. We start from a fairly general description of myosin kinetics, advection and diffusion in the two-phase flow framework, then identify a number of sub-limits of the model that may be relevant in practice, two of which we investigate further via linear stability analyses and numerical simulations. We demonstrate that myosin-driven contraction of the actin network destabilizes a stationary steady state leading to cell motion, but that rapid diffusion of myosin and rapid unbinding of myosin from the actin network are stabilizing. We use numerical simulation to investigate travelling-wave solutions relevant to a steadily gliding cell and we consider a reduction of the model in which the cell adheres strongly to the substrate on which it is crawling. This work demonstrates that a number of existing models for the effect of myosin on cell motility can be understood as different sub-limits of our two-phase flow model.

  2. DEMONSTRATION OF FUEL CELLS TO RECOVER ENERGY FROM LANDFILL GAS: PHASE II. PRETREATMENT SYSTEM PERFORMANCE MEASUREMENT

    Science.gov (United States)

    The report describes Phase II of a demonstration of the utilization of commercial phosphoric acid fuel cells to recover energy from landfill gas. This phase consisted primarily of the construction and testing of a Gas Pretreatment Unit (GPU) whose function is to remove those impu...

  3. The Cell Cycle: An Activity Using Paper Plates to Represent Time Spent in Phases of the Cell Cycle

    Science.gov (United States)

    Scherer, Yvette D.

    2014-01-01

    In this activity, students are given the opportunity to combine skills in math and geometry for a biology lesson in the cell cycle. Students utilize the data they collect and analyze from an online onion-root-tip activity to create a paper-plate time clock representing a 24-hour cell cycle. By dividing the paper plate into appropriate phases of…

  4. The Cell Cycle: An Activity Using Paper Plates to Represent Time Spent in Phases of the Cell Cycle

    Science.gov (United States)

    Scherer, Yvette D.

    2014-01-01

    In this activity, students are given the opportunity to combine skills in math and geometry for a biology lesson in the cell cycle. Students utilize the data they collect and analyze from an online onion-root-tip activity to create a paper-plate time clock representing a 24-hour cell cycle. By dividing the paper plate into appropriate phases of…

  5. Modulation of Autoimmune T-Cell Memory by Stem Cell Educator Therapy: Phase 1/2 Clinical Trial

    OpenAIRE

    Elias Delgado; Marcos Perez-Basterrechea; Beatriz Suarez-Alvarez; Huimin Zhou; Eva Martinez Revuelta; Jose Maria Garcia-Gala; Silvia Perez; Maria Alvarez-Viejo; Edelmiro Menendez; Carlos Lopez-Larrea; Ruifeng Tang; Zhenlong Zhu; Wei Hu; Thomas Moss; Edward Guindi

    2015-01-01

    Background: 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. Methods: In this open-label, phase 1/phase 2 study, Caucasian T1D patients (N = 15) received two treatments wit...

  6. High-pressure sapphire cell for phase equilibria measurements of CO2/organic/water systems.

    Science.gov (United States)

    Pollet, Pamela; Ethier, Amy L; Senter, James C; Eckert, Charles A; Liotta, Charles L

    2014-01-24

    The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. Specifically, the sapphire cell enables visual data collection from multiple loadings to solve a set of material balances to precisely determine phase composition. Ternary phase diagrams can then be established to determine the proportion of each component in each phase at a given condition. In principle, any ternary system can be studied although ternary systems (gas-liquid-liquid) are the specific examples discussed herein. For instance, the ternary THF-Water-CO2 system was studied at 25 and 40 °C and is described herein. Of key importance, this technique does not require sampling. Circumventing the possible disturbance of the system equilibrium upon sampling, inherent measurement errors, and technical difficulties of physically sampling under pressure is a significant benefit of this technique. Perhaps as important, the sapphire cell also enables the direct visual observation of the phase behavior. In fact, as the CO2 pressure is increased, the homogeneous THF-Water solution phase splits at about 2 MPa. With this technique, it was possible to easily and clearly observe the cloud point and determine the composition of the newly formed phases as a function of pressure. The data acquired with the sapphire cell technique can be used for many applications. In our case, we measured swelling and composition for tunable solvents, like gas-expanded liquids, gas-expanded ionic liquids and Organic Aqueous Tunable Systems (OATS)(1-4). For the latest system, OATS, the high-pressure sapphire cell enabled the study of (1) phase behavior as a function of pressure and temperature, (2) composition of each phase (gas-liquid-liquid) as a function of pressure and temperature and (3) catalyst partitioning in the two liquid phases as a function of pressure and composition. Finally, the sapphire cell is an especially effective tool to gather

  7. Cell Cycle Phase Abnormalities Do Not Account for Disordered Proliferation in Barrett's Carcinogenesis

    Directory of Open Access Journals (Sweden)

    Pierre Lao-Sirieix

    2004-11-01

    Full Text Available Barrett's esophagus (BE epithelium is the precursor lesion for esophageal adenocarcinoma. Cell cycle proteins have been advocated as biomarkers to predict the malignant potential in BE. However, whether disruption of the cell cycle plays a causal role in Barrett's carcinogenesis is not clear. Specimens from the Barrett's dysplasia—carcinoma sequence were immunostained for cell cycle phase markers (cyclin D1 for G1; cyclin A for S, G2, and M; cytoplasmic cyclin B1 for G2; and phosphorylated histone 3 for M phase and expressed as a proportion of proliferating cells. Flow cytometric analysis of the cell cycle phase of prospective biopsies was also performed. The proliferation status of nondysplastic BE was similar to gastric antrum and D2, but the proliferative compartment extended to the luminal surface. In dysplastic samples, the number of proliferating cells correlated with the degree of dysplasia (P < .001. The overall levels of cyclins A and B1 correlated with the degree of dysplasia (P < .001. However, the cell cycle phase distribution measured with both immunostaining and flow cytometry was conserved during all stages of BE, dysplasia, and cancer. Hence, the increased proliferation seen in Barrett's carcinogenesis is due to abnormal cell cycle entry or exit, rather than a primary abnormality within the cell cycle.

  8. Constructions of new plateaued functions from known ones

    Institute of Scientific and Technical Information of China (English)

    Zhang Weiguo; Ding Yong; Zhang Ning; Xiao Guozhen

    2008-01-01

    A number of methods for constructing new plateaued functions from known ones are presented. By properly combining the known plateaued functions it is possible to get highly nonlinear resilient plateaued functions. The order, resiliency and propagation characteristics of the constructed plateaued functions are discussed. We show the new functions could possess the desirable cryptographic property.

  9. Optical characterization of red blood cells from individuals with sickle cell trait and disease in Tanzania using quantitative phase imaging

    Science.gov (United States)

    Jung, Jaehwang; Matemba, Lucas E.; Lee, Kyeoreh; Kazyoba, Paul E.; Yoon, Jonghee; Massaga, Julius J.; Kim, Kyoohyun; Kim, Dong-Jin; Park, Yongkeun

    2016-08-01

    Sickle cell disease (SCD) is common across Sub-Saharan Africa. However, the investigation of SCD in this area has been significantly limited mainly due to the lack of research facilities and skilled personnel. Here, we present optical measurements of individual red blood cells from healthy individuals and individuals with SCD and sickle cell trait in Tanzania using the quantitative phase imaging technique. By employing a quantitative phase imaging unit, an existing microscope in a clinic is transformed into a powerful quantitative phase microscope providing measurements on the morphological, biochemical, and biomechanical properties of individual cells. The present approach will open up new opportunities for cost-effective investigation and diagnosis of several diseases in low resource environments.

  10. Optical characterization of red blood cells from individuals with sickle cell trait and disease in Tanzania using quantitative phase imaging

    CERN Document Server

    Jung, JaeHwang; Lee, KyeoReh; Kazyoba, Paul E; Yoon, Jonghee; Massaga, Julius J; Kim, Kyoohyun; Kim, Dong-Jin; Park, YongKeun

    2016-01-01

    Sickle cell disease (SCD) is common across Sub-Saharan Africa. However, the investigation of SCD in this area has been significantly limited mainly due to the lack of research facilities and skilled personnel. Here, we present optical measurements of individual red blood cells (RBCs) from healthy individuals and individuals with SCD and sickle cell trait in Tanzania using the quantitative phase imaging technique. By employing a quantitative phase imaging unit (QPIU), an existing microscope in a clinic is transformed into a powerful quantitative phase microscope providing measurements on the morphological, biochemical, and biomechanical properties of individual cells. The present approach will open up new opportunities for cost-effective investigation and diagnosis of several diseases in low resource environments.

  11. Phase Diagram of Collective Motion of Bacterial Cells in a Shallow Circular Pool

    CERN Document Server

    Wakita, Jun-ichi; Yamamoto, Ken; Katori, Makoto; Yamada, Yasuyuki

    2015-01-01

    The collective motion of bacterial cells in a shallow circular pool is systematically studied using the bacterial species $Bacillus$ $subtilis$. The ratio of cell length to pool diameter (i.e., the reduced cell length) ranges from 0.06 to 0.43 in our experiments. Bacterial cells in a circular pool show various types of collective motion depending on the cell density in the pool and the reduced cell length. The motion is classified into six types, which we call random motion, turbulent motion, one-way rotational motion, two-way rotational motion, random oscillatory motion, and ordered oscillatory motion. Two critical values of reduced cell lengths are evaluated, at which drastic changes in collective motion are induced. A phase diagram is proposed in which the six phases are arranged.

  12. Multi-color phase imaging and sickle cell anemia (Conference Presentation)

    Science.gov (United States)

    Hosseini, Poorya; Zhou, Renjie; Yaqoob, Zahid; So, Peter T. C.

    2016-03-01

    Quantitative phase measurements at multiple wavelengths has created an opportunity for exploring new avenues in phase microscopy such as enhancing imaging-depth (1), measuring hemoglobin concentrations in erythrocytes (2), and more recently in tomographic mapping of the refractive index of live cells (3). To this end, quantitative phase imaging has been demonstrated both at few selected spectral points as well as with high spectral resolution (4,5). However, most of these developed techniques compromise imaging speed, field of view, or the spectral resolution to perform interferometric measurements at multiple colors. In the specific application of quantitative phase in studying blood diseases and red blood cells, current techniques lack the required sensitivity to quantify biological properties of interest at individual cell level. Recently, we have set out to develop a stable quantitative interferometric microscope allowing for measurements of such properties for red cells without compromising field of view or speed of the measurements. The feasibility of the approach will be initially demonstrated in measuring dispersion curves of known solutions, followed by measuring biological properties of red cells in sickle cell anemia. References: 1. Mann CJ, Bingham PR, Paquit VC, Tobin KW. Quantitative phase imaging by three-wavelength digital holography. Opt Express. 2008;16(13):9753-64. 2. Park Y, Yamauchi T, Choi W, Dasari R, Feld MS. Spectroscopic phase microscopy for quantifying hemoglobin concentrations in intact red blood cells. Opt Lett. 2009;34(23):3668-70. 3. Hosseini P, Sung Y, Choi Y, Lue N, Yaqoob Z, So P. Scanning color optical tomography (SCOT). Opt Express. 2015;23(15):19752-62. 4. Jung J-H, Jang J, Park Y. Spectro-refractometry of individual microscopic objects using swept-source quantitative phase imaging. Anal Chem. 2013;85(21):10519-25. 5. Rinehart M, Zhu Y, Wax A. Quantitative phase spectroscopy. Biomed Opt Express. 2012;3(5):958-65.

  13. Switching Characteristics of Phase Change Memory Cell Integrated with Metal-Oxide Semiconductor Field Effect Transistor

    Institute of Scientific and Technical Information of China (English)

    XU Cheng; CHEN Bomy; LIU Bo; CHEN Yi-Feng; LIANG Shuang; SONG Zhi-Tang; FENG Song-Lin; WAN Xu-Dong; YANG Zuo-Ya; XIE Joseph

    2008-01-01

    A Ge2Sb2Te5 based phase change memory device cell integrated with metal-oxide semiconductor field effect transistor (MOSFET) is fabricated using standard 0.18 μm complementary metal-oxide semiconductor process technology.It shows steady switching characteristics in the dc current-voltage measurement.The phase changing phenomenon from crystalline state to amorphous state with a voltage pulse altitude of 2.0 V and pulse width of 50 ns is also obtained.These results show the feasibility of integrating phase change memory cell with MOSFET.

  14. Direct visualization of cell division using high-resolution imaging of M-phase of the cell cycle

    OpenAIRE

    Hesse, Michael; Raulf, Alexandra; Pilz, Gregor-Alexander; Haberlandt, Christian; Klein, Alexandra M; Jabs, Ronald; Zaehres, Holm; Fügemann, Christopher J.; Zimmermann, Katrin; Trebicka, Jonel; Welz, Armin; Pfeifer, Alexander; Röll, Wilhelm; Kotlikoff, Michael I.; Steinhäuser, Christian

    2012-01-01

    Current approaches to monitor and quantify cell division in live cells, and reliably distinguish between acytokinesis and endoreduplication, are limited and complicate determination of stem cell pool identities. Here we overcome these limitations by generating an in vivo reporter system using the scaffolding protein anillin fused to enhanced green fluorescent protein, to provide high spatiotemporal resolution of mitotic phase. This approach visualizes cytokinesis and midbody formation as hall...

  15. Segmentation of the Clustered Cells with Optimized Boundary Detection in Negative Phase Contrast Images.

    Directory of Open Access Journals (Sweden)

    Yuliang Wang

    Full Text Available Cell image segmentation plays a central role in numerous biology studies and clinical applications. As a result, the development of cell image segmentation algorithms with high robustness and accuracy is attracting more and more attention. In this study, an automated cell image segmentation algorithm is developed to get improved cell image segmentation with respect to cell boundary detection and segmentation of the clustered cells for all cells in the field of view in negative phase contrast images. A new method which combines the thresholding method and edge based active contour method was proposed to optimize cell boundary detection. In order to segment clustered cells, the geographic peaks of cell light intensity were utilized to detect numbers and locations of the clustered cells. In this paper, the working principles of the algorithms are described. The influence of parameters in cell boundary detection and the selection of the threshold value on the final segmentation results are investigated. At last, the proposed algorithm is applied to the negative phase contrast images from different experiments. The performance of the proposed method is evaluated. Results show that the proposed method can achieve optimized cell boundary detection and highly accurate segmentation for clustered cells.

  16. Segmentation of the Clustered Cells with Optimized Boundary Detection in Negative Phase Contrast Images.

    Science.gov (United States)

    Wang, Yuliang; Zhang, Zaicheng; Wang, Huimin; Bi, Shusheng

    2015-01-01

    Cell image segmentation plays a central role in numerous biology studies and clinical applications. As a result, the development of cell image segmentation algorithms with high robustness and accuracy is attracting more and more attention. In this study, an automated cell image segmentation algorithm is developed to get improved cell image segmentation with respect to cell boundary detection and segmentation of the clustered cells for all cells in the field of view in negative phase contrast images. A new method which combines the thresholding method and edge based active contour method was proposed to optimize cell boundary detection. In order to segment clustered cells, the geographic peaks of cell light intensity were utilized to detect numbers and locations of the clustered cells. In this paper, the working principles of the algorithms are described. The influence of parameters in cell boundary detection and the selection of the threshold value on the final segmentation results are investigated. At last, the proposed algorithm is applied to the negative phase contrast images from different experiments. The performance of the proposed method is evaluated. Results show that the proposed method can achieve optimized cell boundary detection and highly accurate segmentation for clustered cells.

  17. Therapeutic dendritic cell vaccination of patients with metastatic renal cell carcinoma: a clinical phase 1/2 trial

    DEFF Research Database (Denmark)

    Berntsen, Annika; Trepiakas, Redas; Wenandy, Lynn;

    2008-01-01

    Therapeutic dendritic cell (DC) vaccination against cancer is a strategy aimed at activating the immune system to recognize and destroy tumor cells. In this nonrandomized phase 1/2 trial, we investigated the safety, feasibility, induction of T-cell response, and clinical response after treatment...... with a DC-based vaccine in patients with metastatic renal cell carcinoma. Twenty-seven patients with progressive cytokine-refractory metastatic renal cell carcinoma were vaccinated with DCs loaded with either a cocktail of survivin and telomerase peptides or tumor lysate depending on their HLA-A2 haplotype...

  18. Cell cycle synchronization reveals greater G2/M-phase accumulation of lung epithelial cells exposed to titanium dioxide nanoparticles.

    Science.gov (United States)

    Medina-Reyes, Estefany I; Bucio-López, Laura; Freyre-Fonseca, Verónica; Sánchez-Pérez, Yesennia; García-Cuéllar, Claudia M; Morales-Bárcenas, Rocío; Pedraza-Chaverri, José; Chirino, Yolanda I

    2015-03-01

    Titanium dioxide has been classified in the 2B group as a possible human carcinogen by the International Agency for Research on Cancer, and amid concerns of its exposure, cell cycle alterations are an important one. However, several studies show inconclusive effects, mainly because it is difficult to compare cell cycle effects caused by TiO2 nanoparticle (NP) exposure between different shapes and sizes of NP, cell culture types, and time of exposure. In addition, cell cycle is frequently analyzed without cell cycle synchronization, which may also mask some effects. We hypothesized that synchronization after TiO2 NP exposure could reveal dissimilar cell cycle progression when compared with unsynchronized cell population. To test our hypothesis, we exposed lung epithelial cells to 1 and 10 μg/cm(2) TiO2 NPs for 7 days and one population was synchronized by serum starvation and inhibition of ribonucleotide reductase using hydroxyurea. Another cell population was exposed to TiO2 NPs under the same experimental conditions, but after treatments, cell cycle was analyzed without synchronization. Our results showed that TiO2 NP-exposed cells without synchronization had no changes in cell cycle distribution; however, cell population synchronized after 1 and 10 μg/cm(2) TiO2 NP treatment showed a 1.5-fold and 1.66-fold increase, respectively, in proliferation. Synchronized cells also reveal a faster capability of TiO2 NP-exposed cells to increase cell population in the G2/M phase in the following 9 h after synchronization. We conclude that synchronization discloses a greater percentage of cells in the G2/M phase and higher proliferation than TiO2 NP-synchronized cells.

  19. S-phase-dependent cell cycle disturbances caused by Aleutian mink disease parvovirus

    DEFF Research Database (Denmark)

    Oleksiewicz, M.B.; Alexandersen, Søren

    1997-01-01

    We examined replication of the autonomous parovirus Aleutian mink disease parovirus (ADV) in relation to cell cycle progression of permissive Crandell feline kidney (CRFK) cells. Flow cytometric analysis showed that ADV caused a composite, binary pattern of cell cycle arrest. ADV-induced cell cycle...... with subthreshold levels of ADV products through the late S/G(2) block and, consequently, that the binary pattern of ADV-induced cell cycle arrest may be governed merely by viral replication levels within a single S phase. Flow cytometric analysis of propidium iodide fluorescence and bromodeoxyuridine uptake showed...... that population A cells sustained significantly higher levels of DNA replication than population B cells during the ADV-induced cell cycle arrest. Therefore, the type of ADV-induced cell cycle arrest was not trivial and could have implications for subsequent viral replication in the target cell....

  20. Regulation of the G1 phase of the mammalian cell cycle

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In any multi-cellular organism, the balance between cell division and cell death maintains a constant cell num ber. Both cell division cycle and cell death are highly regulated events. Whether the cell will proceed through the cycle or not, depends upon whether the conditions re quired at the checkpoints during the cycle are filfilled. In higher eucaryotic cells, such as mammalian cells, signals that arrest the cycle usually act at a G1 checkpoint. Cells that pass this restriction point are committed to complete the cycle. Regulation of the G1 phase of the cell cycle is extremely complex and involves many different families of proteins such as retinoblastoma family, cyclin dependent kinases, cyclins, and cyclin kinase inhibitors.

  1. Using digital inline holographic microscopy and quantitative phase contrast imaging to assess viability of cultured mammalian cells

    Science.gov (United States)

    Missan, Sergey; Hrytsenko, Olga

    2015-03-01

    Digital inline holographic microscopy was used to record holograms of mammalian cells (HEK293, B16, and E0771) in culture. The holograms have been reconstructed using Octopus software (4Deep inwater imaging) and phase shift maps were unwrapped using the FFT-based phase unwrapping algorithm. The unwrapped phase shifts were used to determine the maximum phase shifts in individual cells. Addition of 0.5 mM H2O2 to cell media produced rapid rounding of cultured cells, followed by cell membrane rupture. The cell morphology changes and cell membrane ruptures were detected in real time and were apparent in the unwrapped phase shift images. The results indicate that quantitative phase contrast imaging produced by the digital inline holographic microscope can be used for the label-free real time automated determination of cell viability and confluence in mammalian cell cultures.

  2. Argalis on the Qinghai-Tibet Plateau

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The argali are listed by the State as animals subject tosecond-class protection,and no killing is allowed. The international communitylists argali on the Qinghai-Tibet Plateau as animals that must not be hunted.

  3. Colorado Plateau Rapid Ecoregion Assessment Data Catalog

    Data.gov (United States)

    Bureau of Land Management, Department of the Interior — Datasets used in the analysis of the Colorado Plateau (COP) Rapid Ecoregion Assessment (REA).They can be downloaded via a layer package (lpk, similar to a zip file...

  4. Decrease in spermidine content during logarithmic phase of cell growth delays spore formation of Bacillus subtilis.

    Science.gov (United States)

    Ishii, I; Takada, H; Terao, K; Kakegawa, T; Igarashi, K; Hirose, S

    1994-11-01

    Bacillus subtilis 168M contained a large amount of spermidine during the logarithmic phase of growth, but the amount decreased drastically during the stationary phase. The extracts, prepared from B. subtilis cells harvested in the logarithmic phase, contained activity of arginine decarboxylase (ADC) rather than the activity of ornithine decarboxylase. In the presence of alpha-difluoromethylarginine (DFMA), a specific and irreversible inhibitor of ADC, the amount of spermidine in B. subtilis during the logarithmic phase decreased to about 25% of the control cells. Under these conditions, spore formation of B. subtilis 168M delayed greatly without significant inhibition of cell growth. The decrease in spermidine content in the logarithmic phase rather than in the stationary phase was involved in the delay of sporulation. Electron microscopy of cells at 24 hrs. of culture confirmed the delay of spore formation by the decrease of spermidine content. Furthermore, the delay of sporulation was negated by the addition of spermidine. These data suggest that a large amount of spermidine existing during the logarithmic phase plays an important role in the sporulation of B. subtilis.

  5. Cell-laden microgel prepared using a biocompatible aqueous two-phase strategy.

    Science.gov (United States)

    Liu, Yang; Nambu, Natalia Oshima; Taya, Masahito

    2017-09-01

    Microfluidic methods are frequently used to produce cell-laden microgels for various biomedical purposes. Such microfluidic methods generally employ oil-water systems. The poor distribution of crosslinking reagents in the oil phase limits the available gelation strategies. Extracting the microgel from the oil-phase also reduces its production efficiency. In this study, an aqueous two-phase system (ATPS) involving dextran (DEX) and polyethylene glycol (PEG) was used to prepare cell-laden microgel. This avoided the problems associated with an oil phase. The microgel precursor polymers and crosslinking reagents were dispersed in the DEX and PEG phases, respectively. The ultra-low interfacial tension of the ATPS hindered droplet formation. A co-flow microfluidic device was fabricated to overcome this problem. The device incorporated a square-wave-changing injection force, to improve the efficiency of droplet formation. The microgel precursor (including alginate and carboxymethyl cellulose derivatives possessing phenolic hydroxyl moieties) could be dispersed in the DEX solution at various concentrations. Uniform droplets were formed with controllable diameters, and were sequentially converted to microgel by horseradish peroxidase-catalyzed crosslinking. Cells were dispersed in the DEX phase with the microgel precursor polymer, and retained their high viability and proliferation in the resulting microgel. The solubility of gelatin derivatives in the DEX phase was low, but was sufficient to impart cell adhesion properties on the microgel.

  6. DEMONSTRATION OF FUEL CELLS TO RECOVER ENERGY FROM LANDFILL GAS - PHASE III. DEMONSTRATION TESTS - PHASE IV. GUIDELINES AND RECOMMENDATIONS- VOLUME 1. TECHNICAL REPORT

    Science.gov (United States)

    The report summarizes the results of a four-phase program to demonstrate that fuel cell energy recovery using a commercial phosphoric acid fuel cell is both environmentally sound and commercially feasible. Phase I, a conceptual design and evaluation study, addressed the technical...

  7. Development of advanced fuel cell system, phase 3

    Science.gov (United States)

    Handley, L. M.; Meyer, A. P.; Bell, W. F.

    1975-01-01

    A multiple task research and development program was performed to improve the weight, life, and performance characteristics of hydrogen-oxygen alkaline fuel cells for advanced power systems. Gradual wetting of the anode structure and subsequent long-term performance loss was determined to be caused by deposition of a silicon-containing material on the anode. This deposit was attributed to degradation of the asbestos matrix, and attention was therefore placed on development of a substitute matrix of potassium titanate. An 80 percent gold 20 percent platinum catalyst cathode was developed which has the same performance and stability as the standard 90 percent gold - 10 percent platinum cathode but at half the loading. A hybrid polysulfone/epoxy-glass fiber frame was developed which combines the resistance to the cell environment of pure polysulfone with the fabricating ease of epoxy-glass fiber laminate. These cell components were evaluated in various configurations of full-size cells. The ways in which the baseline engineering model system would be modified to accommodate the requirements of the space tug application are identified.

  8. Quantitative evaluation of regularized phase retrieval algorithms on bone scaffolds seeded with bone cells

    Science.gov (United States)

    Weber, L.; Langer, M.; Tavella, S.; Ruggiu, A.; Peyrin, F.

    2016-05-01

    In the field of regenerative medicine, there has been a growing interest in studying the combination of bone scaffolds and cells that can maximize newly formed bone. In-line phase-contrast x-ray tomography was used to image porous bone scaffolds (Skelite©), seeded with bone forming cells. This technique allows the quantification of both mineralized and soft tissue, unlike with classical x-ray micro-computed tomography. Phase contrast images were acquired at four distances. The reconstruction is typically performed in two successive steps: phase retrieval and tomographic reconstruction. In this work, different regularization methods were applied to the phase retrieval process. The application of a priori terms for heterogeneous objects enables quantitative 3D imaging of not only bone morphology, mineralization, and soft tissue formation, but also cells trapped in the pre-bone matrix. A statistical study was performed to derive statistically significant information on the different culture conditions.

  9. Pyramid Schemes on the Tibetan Plateau

    OpenAIRE

    Devin Gonier; Rgyal yum sgrol ma

    2012-01-01

    The unique features of pyramid schemes and certain underlying causes for their development on the Tibetan Plateau are analyzed. Research was conducted by analyzing 521 surveys, allowing estimation of pyramid scheme activity on the Plateau and an identification of related cultural and social specificities. Firsthand accounts were collected revealing details of personal involvement. Survey data and similarities in the accounts were studied to suggest how involvement in pyramid schemes might be ...

  10. Partitioning of Nanoparticles into Organic Phases and Model Cells

    Energy Technology Data Exchange (ETDEWEB)

    Posner, J.D.; Westerhoff, P.; Hou, W-C.

    2011-08-25

    There is a recognized need to understand and predict the fate, transport and bioavailability of engineered nanoparticles (ENPs) in aquatic and soil ecosystems. Recent research focuses on either collection of empirical data (e.g., removal of a specific NP through water or soil matrices under variable experimental conditions) or precise NP characterization (e.g. size, degree of aggregation, morphology, zeta potential, purity, surface chemistry, and stability). However, it is almost impossible to transition from these precise measurements to models suitable to assess the NP behavior in the environment with complex and heterogeneous matrices. For decades, the USEPA has developed and applies basic partitioning parameters (e.g., octanol-water partition coefficients) and models (e.g., EPI Suite, ECOSAR) to predict the environmental fate, bioavailability, and toxicity of organic pollutants (e.g., pesticides, hydrocarbons, etc.). In this project we have investigated the hypothesis that NP partition coefficients between water and organic phases (octanol or lipid bilayer) is highly dependent on their physiochemical properties, aggregation, and presence of natural constituents in aquatic environments (salts, natural organic matter), which may impact their partitioning into biological matrices (bioaccumulation) and human exposure (bioavailability) as well as the eventual usage in modeling the fate and bioavailability of ENPs. In this report, we use the terminology "partitioning" to operationally define the fraction of ENPs distributed among different phases. The mechanisms leading to this partitioning probably involve both chemical force interactions (hydrophobic association, hydrogen bonding, ligand exchange, etc.) and physical forces that bring the ENPs in close contact with the phase interfaces (diffusion, electrostatic interactions, mixing turbulence, etc.). Our work focuses on partitioning, but also provides insight into the relative behavior of ENPs as either "more like

  11. Partitioning of Nanoparticles into Organic Phases and Model Cells

    Energy Technology Data Exchange (ETDEWEB)

    Posner, J.D.; Westerhoff, P.; Hou, W-C.

    2011-08-25

    There is a recognized need to understand and predict the fate, transport and bioavailability of engineered nanoparticles (ENPs) in aquatic and soil ecosystems. Recent research focuses on either collection of empirical data (e.g., removal of a specific NP through water or soil matrices under variable experimental conditions) or precise NP characterization (e.g. size, degree of aggregation, morphology, zeta potential, purity, surface chemistry, and stability). However, it is almost impossible to transition from these precise measurements to models suitable to assess the NP behavior in the environment with complex and heterogeneous matrices. For decades, the USEPA has developed and applies basic partitioning parameters (e.g., octanol-water partition coefficients) and models (e.g., EPI Suite, ECOSAR) to predict the environmental fate, bioavailability, and toxicity of organic pollutants (e.g., pesticides, hydrocarbons, etc.). In this project we have investigated the hypothesis that NP partition coefficients between water and organic phases (octanol or lipid bilayer) is highly dependent on their physiochemical properties, aggregation, and presence of natural constituents in aquatic environments (salts, natural organic matter), which may impact their partitioning into biological matrices (bioaccumulation) and human exposure (bioavailability) as well as the eventual usage in modeling the fate and bioavailability of ENPs. In this report, we use the terminology "partitioning" to operationally define the fraction of ENPs distributed among different phases. The mechanisms leading to this partitioning probably involve both chemical force interactions (hydrophobic association, hydrogen bonding, ligand exchange, etc.) and physical forces that bring the ENPs in close contact with the phase interfaces (diffusion, electrostatic interactions, mixing turbulence, etc.). Our work focuses on partitioning, but also provides insight into the relative behavior of ENPs as either "more like

  12. A phase II trial of chimeric monoclonal antibody G250 for advanced renal cell carcinoma patients.

    NARCIS (Netherlands)

    Bleumer, I.; Knuth, A.; Oosterwijk, E.; Hofmann, R.; Varga, Z.; Lamers, C.B.H.W.; Kruit, W.; Melchior, S.; Mala, C.; Ullrich, S.; Mulder, P.; Mulders, P.F.A.; Beck, J.L.M.

    2004-01-01

    Chimeric monoclonal antibody G250 (WX-G250) binds to a cell surface antigen found on >90% of renal cell carcinoma (RCC). A multicentre phase II study was performed to evaluate the safety and efficacy of WX-G250 in metastatic RCC (mRCC) patients. In all, 36 patients with mRCC were included. WX-G250 w

  13. Single cell analysis reveals the stochastic phase of reprogramming to pluripotency is an ordered probabilistic process.

    Directory of Open Access Journals (Sweden)

    Kyung-Min Chung

    Full Text Available Despite years of research, the reprogramming of human somatic cells to pluripotency remains a slow, inefficient process, and a detailed mechanistic understanding of reprogramming remains elusive. Current models suggest reprogramming to pluripotency occurs in two-phases: a prolonged stochastic phase followed by a rapid deterministic phase. In this paradigm, the early stochastic phase is marked by the random and gradual expression of pluripotency genes and is thought to be a major rate-limiting step in the successful generation of induced Pluripotent Stem Cells (iPSCs. Recent evidence suggests that the epigenetic landscape of the somatic cell is gradually reset during a period known as the stochastic phase, but it is known neither how this occurs nor what rate-limiting steps control progress through the stochastic phase. A precise understanding of gene expression dynamics in the stochastic phase is required in order to answer these questions. Moreover, a precise model of this complex process will enable the measurement and mechanistic dissection of treatments that enhance the rate or efficiency of reprogramming to pluripotency. Here we use single-cell transcript profiling, FACS and mathematical modeling to show that the stochastic phase is an ordered probabilistic process with independent gene-specific dynamics. We also show that partially reprogrammed cells infected with OSKM follow two trajectories: a productive trajectory toward increasingly ESC-like expression profiles or an alternative trajectory leading away from both the fibroblast and ESC state. These two pathways are distinguished by the coordinated expression of a small group of chromatin modifiers in the productive trajectory, supporting the notion that chromatin remodeling is essential for successful reprogramming. These are the first results to show that the stochastic phase of reprogramming in human fibroblasts is an ordered, probabilistic process with gene-specific dynamics and to

  14. Single cell analysis reveals the stochastic phase of reprogramming to pluripotency is an ordered probabilistic process.

    Science.gov (United States)

    Chung, Kyung-Min; Kolling, Frederick W; Gajdosik, Matthew D; Burger, Steven; Russell, Alexander C; Nelson, Craig E

    2014-01-01

    Despite years of research, the reprogramming of human somatic cells to pluripotency remains a slow, inefficient process, and a detailed mechanistic understanding of reprogramming remains elusive. Current models suggest reprogramming to pluripotency occurs in two-phases: a prolonged stochastic phase followed by a rapid deterministic phase. In this paradigm, the early stochastic phase is marked by the random and gradual expression of pluripotency genes and is thought to be a major rate-limiting step in the successful generation of induced Pluripotent Stem Cells (iPSCs). Recent evidence suggests that the epigenetic landscape of the somatic cell is gradually reset during a period known as the stochastic phase, but it is known neither how this occurs nor what rate-limiting steps control progress through the stochastic phase. A precise understanding of gene expression dynamics in the stochastic phase is required in order to answer these questions. Moreover, a precise model of this complex process will enable the measurement and mechanistic dissection of treatments that enhance the rate or efficiency of reprogramming to pluripotency. Here we use single-cell transcript profiling, FACS and mathematical modeling to show that the stochastic phase is an ordered probabilistic process with independent gene-specific dynamics. We also show that partially reprogrammed cells infected with OSKM follow two trajectories: a productive trajectory toward increasingly ESC-like expression profiles or an alternative trajectory leading away from both the fibroblast and ESC state. These two pathways are distinguished by the coordinated expression of a small group of chromatin modifiers in the productive trajectory, supporting the notion that chromatin remodeling is essential for successful reprogramming. These are the first results to show that the stochastic phase of reprogramming in human fibroblasts is an ordered, probabilistic process with gene-specific dynamics and to provide a precise

  15. Effects of proliferation on the decay of thermotolerance in Chinese hamster cells.

    Science.gov (United States)

    Armour, E P; Li, G C; Hahn, G M

    1985-09-01

    Development and decay of thermotolerance were observed in Chinese hamster HA-1 cells. The thermotolerance kinetics of exponentially growing and fed plateau-phase cells were compared. Following a 10-min heat exposure at 45 degrees C, cells in both growth states had similar rates of development of tolerance to a subsequent 45-min exposure at 45 degrees C. This thermotolerant state started to decay between 12 and 24 hr after the initial heat exposure. The decay appeared to initiate slightly sooner in the exponentially growing cells when compared to the fed plateau-phase cells. During the decay phase, the rate of thermotolerance decay was similar in the two growth conditions. In other experiments, cells were induced to divide at a slower rate by chronic growth (3 months) in a low concentration of fetal calf serum. Under these low serum conditions cells became more sensitive to heat and the rate of decay of thermotolerance remained the same for exponentially growing cells. Plateau-phase cells were also more sensitive, but thermotolerance decayed more rapidly in these cells. Although dramatic cell cycle perturbations were seen in the exponentially growing cells, these changes appeared not to be related to thermotolerance kinetics.

  16. Dynamics of HBV cccDNA expression and transcription in different cell growth phase

    Directory of Open Access Journals (Sweden)

    Chong Chin-Liew

    2011-12-01

    Full Text Available Abstract Background The covalently closed-circular DNA (cccDNA of hepatitis B virus (HBV is associated with viral persistence in HBV-infected hepatocytes. However, the regulation of cccDNA and its transcription in the host cells at different growth stages is not well understood. Methods We took advantages of a stably HBV-producing cell line, 1.3ES2, and examine the dynamic changes of HBV cccDNA, viral transcripts, and viral replication intermediates in different cellular growth stages. Results In this study, we showed that cccDNA increased suddenly in the initial proliferation phase of cell growth, probably attributable to its nuclear replenishment by intracellular nucleocapsids. The amount of cccDNA then decreased dramatically in the cells during their exponential proliferation similar to the loss of extrachromosomal plasmid DNA during cell division, after which it accumulated gradually while the host cells grew to confluency. We found that cccDNA was reduced in dividing cells and could be removed when proliferating cells were subjected to long term of lamivudine (3TC treatment. The amounts of viral replicative intermediates were rapidly reduced in these proliferating cells and were significantly increased after cells reaching confluency. The expression levels of viral transcripts were increased in parallel with the elevated expression of hepatic transcription factors (HNF4α, CEBPα, PPARα, etc. during cell growth confluency. The HBV transcripts were transcribed from both integrated viral genome and cccDNA, however the transcriptional abilities of cccDNA was less efficient then that from integrated viral genome in all cell growth stages. We also noted increases in the accumulation of intracellular viral particles and the secretion of mature virions as the cells reached confluency and ceased to grow. Conclusions Based on the dynamics of HBV replication, we propose that HBV replication is modulated differently in the different stages of cell

  17. Prospects and challenges of quantitative phase imaging in tumor cell biology

    Science.gov (United States)

    Kemper, Björn; Götte, Martin; Greve, Burkhard; Ketelhut, Steffi

    2016-03-01

    Quantitative phase imaging (QPI) techniques provide high resolution label-free quantitative live cell imaging. Here, prospects and challenges of QPI in tumor cell biology are presented, using the example of digital holographic microscopy (DHM). It is shown that the evaluation of quantitative DHM phase images allows the retrieval of different parameter sets for quantification of cellular motion changes in migration and motility assays that are caused by genetic modifications. Furthermore, we demonstrate simultaneously label-free imaging of cell growth and morphology properties.

  18. Programming voltage reduction in phase change memory cells with tungsten trioxide bottom heating layer/electrode.

    Science.gov (United States)

    Rao, Feng; Song, Zhitang; Gong, Yuefeng; Wu, Liangcai; Feng, Songlin; Chen, Bomy

    2008-11-05

    A phase change memory cell with tungsten trioxide bottom heating layer/electrode is investigated. The crystalline tungsten trioxide heating layer promotes the temperature rise in the Ge(2)Sb(2)Te(5) layer which causes the reduction in the reset voltage compared to a conventional phase change memory cell. Theoretical thermal simulation and calculation for the reset process are applied to understand the thermal effect of the tungsten trioxide heating layer/electrode. The improvement in thermal efficiency of the PCM cell mainly originates from the low thermal conductivity of the crystalline tungsten trioxide material.

  19. Renal cell carcinoma metastases to the pancreas - Value of arterial phase imaging at MDCT

    Energy Technology Data Exchange (ETDEWEB)

    Corwin, Michael T. [Univ. of California, Davis Medical Center, Dept. of Radiology, Sacramento (United States)], e-mail: Michael.corwin@ucdmc.ucdavis.edu; Lamba, Ramit; McGahan, John P. [Univ. of California, Davis Medical Center, Dept. of Radiology, Sacramento (United States); Wilson, Machelle [Univ. of California, Davis, Dept. of Public Health Sciences (United States)

    2013-04-15

    Background: The pancreas is an increasingly recognized site of renal cell carcinoma metastases. It is important to determine the optimal MDCT protocol to best detect RCC metastases to the pancreas. Purpose: To compare the rate of detection of renal cell carcinoma metastases to the pancreas between arterial and portal venous phase MDCT. Material and Methods: A retrospective review of CTs of the abdomen yielded six patients with metastatic RCC to the pancreas. Five of six patients had pathologically proven clear cell RCC. Two blinded reviewers independently reported the number of pancreatic lesions seen in arterial and venous phases. Each lesion was graded as definite or possible. The number of lesions was determined by consensus review of both phases. Attenuation values were obtained for metastatic lesions and adjacent normal pancreas in both phases. Results: There were a total of 24 metastatic lesions to the pancreas. Reviewer 1 identified 20/24 (83.3%) lesions on the arterial phase images and 13/24 (54.2%) lesions on the venous phase. Seventeen of 20 (85.0%) arterial lesions were deemed definite and 9/13 (69.2%) venous lesions were definite. Reviewer 2 identified 19/24 (79.2%) lesions on the arterial phase and 14/24 (58.3%) on the venous phase. Seventeen of 19 (89.5%) arterial lesions were definite and 7/14 (50%) venous lesions were definite. Mean attenuation differential between lesion and pancreas was 114 HU and 39 HU for arterial and venous phases, respectively (P<0.0001). Conclusion: Detection of RCC metastases to the pancreas at MDCT is improved using arterial phase imaging compared to portal venous phase imaging.

  20. New insights in Microbial Fuel Cells: novel solid phase anolyte

    Science.gov (United States)

    Tommasi, Tonia; Salvador, Gian Paolo; Quaglio, Marzia

    2016-07-01

    For the development of long lasting portable microbial fuel cells (MFCs) new strategies are necessary to overcome critical issues such as hydraulic pump system and the biochemical substrate retrieval overtime to sustain bacteria metabolism. The present work proposes the use of a synthetic solid anolyte (SSA), constituted by agar, carbonaceous and nitrogen sources dissolved into diluted seawater. Results of a month-test showed the potential of the new SSA-MFC as a long lasting low energy consuming system.

  1. Pirarubicin inhibits multidrug-resistant osteosarcoma cell proliferation through induction of G2/M phase cell cycle arrest

    Science.gov (United States)

    Zheng, Shui-er; Xiong, Sang; Lin, Feng; Qiao, Guang-lei; Feng, Tao; Shen, Zan; Min, Da-liu; Zhang, Chun-ling; Yao, Yang

    2012-01-01

    Aim: Pirarubicin (THP) is recently found to be effective in treating patients with advanced, relapsed or recurrent high-grade osteosarcoma. In this study, the effects of THP on the multidrug-resistant (MDR) osteosarcoma cells were assessed, and the underlying mechanisms for the disruption of cell cycle kinetics by THP were explored. Methods: Human osteosarcoma cell line MG63 and human MDR osteosarcoma cell line MG63/DOX were tested. The cytotoxicity of drugs was examined using a cell proliferation assay with the Cell Counting Kit-8 (CCK-8). The distribution of cells across the cell cycle was determined with flow cytometry. The expression of cell cycle-regulated genes cyclin B1 and Cdc2 (CDK1), and the phosphorylated Cdc2 and Cdc25C was examined using Western blot analyses. Results: MG63/DOX cells were highly resistant to doxorubicin (ADM) and gemcitabine (GEM), but were sensitive or lowly resistant to THP, methotrexate (MTX) and cisplatin (DDP). Treatment of MG63/DOX cells with THP (200–1000 ng/mL) inhibited the cell proliferation in time- and concentration-dependent manners. THP (50–500 ng/mL) induced MG63/DOX cell cycle arrest at the G2/M phase in time- and concentration-dependent manners. Furthermore, the treatment of MG63/DOX cells with THP (200–1000 ng/mL) downregulated cyclin B1 expression, and decreased the phosphorylated Cdc2 at Thr161. Conversely, the treatment increased the phosphorylated Cdc2 at Thr14/Tyr15 and Cdc25C at Ser216, which led to a decrease in Cdc2-cyclin B1 activity. Conclusion: The cytotoxicity of THP to MG63/DOX cells may be in part due to its ability to arrest cell cycle progression at the G2/M phase, which supports the use of THP for managing patients with MDR osteosarcoma. PMID:22580740

  2. In vitro holding and PLD-repair. Pt. 2. A flow cytometric and electron microscopic analysis of some mammalian cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, A.F.G. (Institute for Basic Research in Developmental Disabilities, Staten Island, NY (USA)); Palackal, T. (State Univ. of New York, Brooklyn, NY (USA). Div. of Radiobiology); Lange, C.S. (Kiel Univ. (Germany, F.R.). Abt. Frauenheilkunde)

    1989-12-01

    The repair of potentially lethal damage (PLDR) in mammalian cells is expected to be better in quiescent cultures since PLD is supposedly fixed during cycle progression. Plateau phase cultures, therefore, serve as models because of assumed mitotic quiescence. Four established cell lines (V79, CHO, L5178Y and HELA) and one euploid cell strain IMR-90 have been analysed by flow cytometry and electron microscopy to address questions on quiescence in the plateau phase and the effect of holding (induction of quiescence by nutrient privation). In contrast to commonly held views, our results indicate that the quiescent fraction in cultures from transformed cells is exceedingly low (1% or less). Plateau phase cultures of transformed cells are constantly turning over. Euploid cells like the IMR-90 show true quiescence in the plateau phase. Holding causes typical cytopathological changes. These changes have been ultrastructurely characterised. Resistant sub-populations of cells can be selected out under holding-conditions. Such selected cells show completely different radiobiological characteristics, which raise questions on the interpretation of data on PLDR. (orig.).

  3. Thermochronological evidence for multi-phase uplifting of the East Kunlun Mountains, northern Tibetan Plateau%东昆仑造山带多期隆升历史的地质热年代学证据

    Institute of Scientific and Technical Information of China (English)

    陈宣华; Michael W. MCRIVETTE; 李丽; 尹安; 蒋荣宝; 万景林; 李会军

    2011-01-01

    Multiple phases of Mesozoic and Cenozoic cooling and uplifting events are derived from fission track (FT) dating of zircons and apatites and thermal history modeling of apatite FT ages from several plutons in East Kunlun near Golmud City. Two phases of Mesozoic cooling histories revealed by zircon FT ages are phase I in Jurassic (194.1 -144.4 Ma) and phase II in Early Cretaceous (115.7~100.2 Ma). Three phases of Cenozoic cooling histories revealed by apatite FT ages and thermal history modeling are phase I in early Eocene (~52.9 Ma), phase II in middle Miocene (16.3~10.0 Ma), and phase III in Pliocene (5.1~0.9 Ma), which are considered to be closely related to the activity of Cenozoic East Kunlun thrust system. Cenozoic phase I (~52.9 Ma) cooling is consistent with the short time living of a small foreland basin formed on the north margin of the East Kunlun Mountains. The spatial distribution of apatiteFT ages in Cenozoic phase II (16.3-10.0 Ma) and III (5.1~0.9 Ma) suggests the piggyback thrusting of the East Kunlun thrust system and the forming of piggyback Qaidam Basin as a result of basin-mountain coupling. According to the age comparability of the end of thrusting in Cenozoic phase II and the beginning of the major sinistral strike-slipping of Kunlun Fault, it is inferred that there was a deformational transfer from compressing to shearing at ~10.0 Ma.%对格尔木附近东昆仑山花岗岩类侵入岩体中锆石和磷灰石进行裂变径迹(FT)定年与热历史的模拟,得到了中、新生代东昆仑山多阶段冷却与隆升的构造热历史.锆石FT年龄反映了东昆仑山中生代2期冷却历史,分别为第1期侏罗纪(194.1~144.4Ma)和第2期早白垩世(115.7~100.2Ma)冷却历史.磷灰石FT年龄和热历史模拟给出新生代3期冷却历史,分别为第1期始新世早期(约52.9Ma)、第2期中新世中期(16.3~10.0Ma)和第3期上新世(5.1~0.9Ma)冷却历史.东昆仑山新生代3期冷却历史与逆冲断层系的

  4. Phase reconstruction of living human embryonic kidney 293 cells based on two off-axis holograms

    Science.gov (United States)

    Zhou, Wenjing; Yu, Yingjie; Duan, Yanhong; Asundi, Anand

    2008-11-01

    In this paper, we validate experimentally the potential of off-axis digital micro-holography for 3D image reconstruction of a live Human Embryonic Kidney 293(HEK293) cell that is widely used as transfection and expression. A subtraction method of two off-axis holograms to reconstruct the phase of the live microscopic object is discussed. The presented subtraction method can remove some main noise, for example, the quadratic phase aberration introduced by microscope objective (MO), other phase aberration introduced by the liquid in tank and other interference noise introduced by the optical parts. Thus an improvement in the measurement precision of live cells in aqueous solution is observed. The potential of this method is demonstrated by providing the phase reconstruction results of a phase grating and a single HEK293 cell. The results showed good correspondence to the actual character of HEK293 cell prove the capability of digital micro-holography as a tool to monitor the dynamic transfection process of the living HEK 293 cells.

  5. Phenotypic diversity of diploid and haploid Emiliania huxleyi cells and of cells in different growth phases revealed by comparative metabolomics.

    Science.gov (United States)

    Mausz, Michaela A; Pohnert, Georg

    2015-01-01

    In phytoplankton a high species diversity of microalgae co-exists at a given time. But diversity is not only reflected by the species composition. Within these species different life phases as well as different metabolic states can cause additional diversity. One important example is the coccolithophore Emiliania huxleyi. Diploid cells play an important role in marine ecosystems since they can form massively abundant algal blooms but in addition the less abundant haploid life phase of E. huxleyi occurs in lower quantities. Both life phases may fulfill different functions in the plankton. We hypothesize that in addition to the functional diversity caused by this life phase transition the growth stage of cells can also influence the metabolic composition and thus the ecological impact of E. huxleyi. Here we introduce a metabolomic survey in dependence of life phases as well as different growth phases to reveal such changes. The comparative metabolomic approach is based on the extraction of intracellular metabolites from intact microalgae, derivatization and analysis by gas chromatography coupled to mass spectrometry (GC-MS). Automated data processing and statistical analysis using canonical analysis of principal coordinates (CAP) revealed unique metabolic profiles for each life phase. Concerning the correlations of metabolites to growth phases, complex patterns were observed. As for example the saccharide mannitol showed its highest concentration in the exponential phase, whereas fatty acids were correlated to stationary and sterols to declining phase. These results are indicative for specific ecological roles of these stages of E. huxleyi and are discussed in the context of previous physiological and ecological studies. Copyright © 2014 Elsevier GmbH. All rights reserved.

  6. Adenovirus KH901 promotes 5-FU antitumor efficacy and S phase in LoVo cells.

    Science.gov (United States)

    Peng, Wei; Li, Jin; Yin, X G; Xu, J F; Cheng, L Z

    2012-06-01

    A combination of oncolytic and chemotherapeutic agents has been used to kill cancer cells. However, the effect of oncolytic adenoviruses on the cell cycle remains to be determined. Cytotoxicity assays were performed to determine cell death in cells treated with 5-fluorouracil (5-FU) alone or in combination with the oncolytic adenovirus KH901. Dynamic changes in the cell cycle, cell proliferation, and apoptosis-related proteins including p-AKT, Bcl-2, Bax, and caspase 3 were investigated after treatment with 5-FU with or without KH901. A higher proportion of S-phase cells were observed after treatment with KH901 and 5-FU than with 5-FU alone. p-AKT, Bcl-2, and Bax expression was increased upon treatment with KH901, whereas the expression of caspase-3 was not induced upon treatment with KH901 with or without 5-FU. KH901 exhibited significant potential as an oncolytic adenovirus and increased cell death in combination with 5-FU in LoVo cells, as compared to 5-FU alone. In conclusion, KH901 stimulates LoVo cells to enter the S-phase by activation of p-AKT, which could partly explain its synergistic effect with 5-FU on LoVo cell cytotoxicity.

  7. Pathways for Genome Integrity in G2 Phase of the Cell Cycle

    Directory of Open Access Journals (Sweden)

    Claus Storgaard Sørensen

    2012-11-01

    Full Text Available The maintenance of genome integrity is important for normal cellular functions, organism development and the prevention of diseases, such as cancer. Cellular pathways respond immediately to DNA breaks leading to the initiation of a multi-facetted DNA damage response, which leads to DNA repair and cell cycle arrest. Cell cycle checkpoints provide the cell time to complete replication and repair the DNA damage before it can continue to the next cell cycle phase. The G2/M checkpoint plays an especially important role in ensuring the propagation of error-free copies of the genome to each daughter cell. Here, we review recent progress in our understanding of DNA repair and checkpoint pathways in late S and G2 phases. This review will first describe the current understanding of normal cell cycle progression through G2 phase to mitosis. It will also discuss the DNA damage response including cell cycle checkpoint control and DNA double-strand break repair. Finally, we discuss the emerging concept that DNA repair pathways play a major role in the G2/M checkpoint pathway thereby blocking cell division as long as DNA lesions are present.

  8. Knockdown of nucleophosmin induces S-phase arrest in HepG2 cells

    Institute of Scientific and Technical Information of China (English)

    Qing-Qing Wang; Zhi-Yi Zhang; Jian-Yong Xiao; Chun Yi; Lin-Zi Li; Yan Huang; Jing-Ping Yun

    2011-01-01

    Nucleophosmin/B23 (NPM) is a universally expressed nucleolar phosphoprotein that participates in proliferation,apoptosis,ribosome assembly,and centrosome duplication; however,the role of NPM in cell cycle regulation is not well characterized.We investigated the mechanism by which NPM is involved in cell cycle regulation.NPM was knocked down using siRNA in HepG2 hepatoblastoma cells.NPM translocation following actinomycin D (ActD) treatment was investigated using immunofluorescent staining.Expression of NPM and other factors involved in cell cycle regulation was examined by Westem blotting.Cell cycle distribution was measured using flow cytometry to detect 5-ethynyl-2'-deoxyuddine (EdU) incorporation.Cell proliferation was quantified by the MTT assay.Knockdown of NPM increased the percentage of HepG2 calls in S phase and led to decreased expression of P53 and P21Cp1/WAF1.S-phase arrest in HepG2 cells was significantly enhanced by ActD treatment.Furthermore,knockdown of NPM abrogated ActD-induced G2/M phase call cycle arrest.Taken together,these data demonstrate that inhibition of NPM has a significant effect on the cell cycle.

  9. S-phase delay in human hepatocellular carcinoma cells induced by overexpression of integrin β1

    Institute of Scientific and Technical Information of China (English)

    Yu-Long Liang; Ting-Wen Lei; Heng Wu; Jian-Min Sn; Li-Ying Wang; Qun-Ying Lei; Xi-Liang Zha

    2003-01-01

    AIM:To clarify the mechanisms of integrin overexpression in negatively regulating the cell cycle control of hepatocellular carcinoma cells SMMC-7721.METHODS: The cell cycle pattern was determined by flow cytometry. The mRNA and protein expression levels were assayed by RT-PCR and Western blot, respectively. Stable transfection was performed by Lipofectamine 2000 reagent,and cells were screened by G418.RESULTS: Overexpression of α5β1 or β1 integrin induced S-phase delay in SMMC-7721 cells, and this delay was possibly due to the accumulation of cyclin-dependent kinase inhibitors (CKIs) p21cip1 and p27kip1. The decrease of protein kinase B (PKB) phosphorylation was present in this signaling pathway, but focal adhesion kinase (FAK) was not involved.When phosphorylation of PKB was solely blocked by wortmannin, p27kip1 protein level was increased. Moreover,S-phase delay was recurred when attachment of the parental SMMC-7721 cells was inhibited by the preparation of polyHEME, and this cell cycle pattern was similar to that of β1-7721 or α5β1-7721 cells.CONCLUSION: S-phase delay induced by overexpression of integrin β1 subunit is attributed to the decrease of PKB phosphorylation and subsequent increases of p21cip1 and p27kip1 proteins, and may be involved in the unoccupied α5β1because of lack of its ligands.

  10. [BMMSC from blastic phase CML down-regulate leukemia cell apoptosis].

    Science.gov (United States)

    Wang, Ying; Han, Yu-Xiang; Niu, Zhi-Yun; Wang, Xing-Zhe; Hua, Huan; Shang, Yin-Tao; Wang, Fu-Xu; Zhang, Xue-Jun; Luo, Jian-Min

    2014-10-01

    The purpose of this study was to investigate the effect of bone marrow mesenchymal stem cells (BMMSC) from patients with chronic myeloid leukemia (CML) in blastic phase (Bp) on K562 cells and the primary CML-Bp cells, and to explore its potential mechanisms. K562 cells and primary CML-Bp cells were co-cultured with BMMSC of different groups; the cell proliferation was detected by MTT method, the cell apoptosis rate and mitochondrial membrane potential were measured by flow cytometry, the expression levels of Caspase-8, Caspase-9, and activated Caspase-3 in cells were measured by Western blot. The results showed that the CML-Bp BMMSC could enhance the survival rate of K562 cells treated with adviamycin (ADM) and display protective effect on K562 cells and primary CML-Bp mononuctear cells, inhibited ADM-induced leukimia cell apoptosis (P < 0.05); as compared with CML-chronic phase (CML-Cp) BMMSC and normal BMMSC, the CML-Bp BMMSC showed the highest protective effect on leukemic cells, the mitochondrial membrane potential of co-cultured cells slightly droped (P < 0.05). In the CML-Bp BMMSC cultured with K562 cells, the expression level of caspase-3 was more down-regulated than that in K562 alone plus ADM group, while the expression of caspase-9 significantly increased (P < 0.05). It is concluded that the CML-Bp BMMSC down-regulates ADM-induced leukemia cell appoptosis, its mechanism may relate with the inhibition of mitochondrial membrane potential drop, the stabilization of unactive expression of caspase-9 and down-regulation of caspase-3 expression.

  11. Near-critical fluctuations and cytoskeleton-assisted phase separation lead to subdiffusion in cell membranes

    CERN Document Server

    Ehrig, Jens; Schwille, Petra

    2010-01-01

    We address the relationship between membrane microheterogeneity and anomalous subdiffusion in cell membranes by carrying out Monte Carlo simulations of two-component lipid membranes. We find that near-critical fluctuations in the membrane lead to transient subdiffusion, while membrane-cytoskeleton interaction strongly affects phase separation, enhances subdiffusion, and eventually leads to hop diffusion of lipids. Thus, we present a minimum realistic model for membrane rafts showing the features of both microscopic phase separation and subdiffusion.

  12. Measuring dynamic membrane fluctuations in cell membrane using quantitative phase imaging (Conference Presentation)

    Science.gov (United States)

    Lee, SangYun; Kim, Kyoohyun; Park, YongKeun

    2017-02-01

    There is a strong correlation between the dynamic membrane fluctuations and the biomechanical properties of living cells. The dynamic membrane fluctuation consists of submicron displacements, and can be altered by changing the cells' pathophysiological conditions. These results have significant relevance to the understanding of RBC biophysics and pathology, as follows. RBCs must withstand large mechanical deformations during repeated passages through the microvasculature and the fenestrated walls of the splenic sinusoids. This essential ability is diminished with senescence, resulting in physiological destruction of the aging RBCs. Pathological destruction of the red cells, however, occurs in cells affected by a host of diseases such as spherocytosis, malaria, and Sickle cell disease, as RBCs depart from their normal discoid shape and lose their deformability. Therefore, quantifying the RBC deformability insight into a variety of problems regarding the interplay of cell structure, dynamics, and function. Furthermore, the ability to monitor mechanical properties of RBCs is of vital interest in monitoring disease progression or response to treatment as molecular and pharmaceutical approaches for treatment of chronic diseases. Here, we present the measurements of dynamic membrane fluctuations in live cells using quantitative phase imaging techniques. Measuring both the 3-D refractive index maps and the dynamic phase images of live cells are simultaneously measured, from which dynamic membrane fluctuation and deformability of cells are precisely calculated. We also present its applications to various diseases ranging from sickle cell diseases, babesiosis, and to diabetes.

  13. Hilbert phase dynamometry (HPD) for real-time measurement of cell generated forces (Conference Presentation)

    Science.gov (United States)

    Sridharan, Shamira; Li, Yanfen; Bhaduri, Basanta; Majeed, Hassaan; Dupenloup, Paul; Levine, Alex; Kilian, Kristopher A.; Popescu, Gabriel

    2016-03-01

    Traction force microscopy is the most widely used technique for studying the forces exerted by cells on deformable substrates. However, the method is computationally intense and cells have to be detached from the substrate prior to measuring the displacement map. We have developed a new method, referred to as Hilbert phase dynamometry (HPD), which yields real-time force fields and, simultaneously, cell dry mass and growth information. HPD operates by imaging cells on a deformable substrate that is patterned with a grid of fluorescent proteins. A Hilbert transform is used to extract the phase map associated with the grid deformation, which provides the displacement field. By combining this information with substrate stiffness, an elasticity model was developed to measure forces exerted by cells with high spatial resolution. In our study, we prepared 10kPa gels and them with a 2-D grid of FITC-conjugated fibrinogen/fibronectin mixture, an extracellular matrix protein to which cells adhere. We cultured undifferentiated mesenchymal stem cells (MSC), and MSCs that were in the process of undergoing adipogenesis and osteogenesis. The cells were measured over the course of 24 hours using Spatial Light Interference Microscopy (SLIM) and wide-field epi-fluorescence microscopy allowing us to simultaneously measure cell growth and the forces exerted by the cells on the substrate.

  14. Monitoring of live cell cultures during apoptosis by phase imaging and Raman spectroscopy

    Science.gov (United States)

    Sharikova, Anna; Saide, George; Sfakis, Lauren; Park, Jun Yong; Desta, Habben; Maloney, Maxwell C.; Castracane, James; Mahajan, Supriya D.; Khmaladze, Alexander

    2017-02-01

    Non-invasive live cell measurements are an important tool in biomedical research. We present a combined digital holography/Raman spectroscopy technique to study live cell cultures during apoptosis. Digital holographic microscopy records an interference pattern between object and reference waves, so that the computationally reconstructed holographic image contains both amplitude and phase information about the sample. When the phase is mapped across the sample and converted into height information for each pixel, a three dimensional image is obtained. The measurement of live cell cultures by digital holographic microscopy yields information about cell shape and volume, changes to which are reflective of alterations in cell cycle and initiation of cell death mechanisms. Raman spectroscopy, on the other hand, is sensitive to rotational and vibrational molecular transitions, as well as intermolecular vibrations. Therefore, Raman spectroscopy provides complementary information about cells, such as protein, lipid and nucleic acid content, and, particularly, the spectral signatures associated with structural changes in molecules. The cell cultures are kept in the temperature-controlled environmental chamber during the experiment, which allows monitoring over multiple cell cycles. The DHM system combines a visible (red) laser source with conventional microscope base, and LabVIEW-run data processing. We analyzed and compared cell culture information obtained by these two methods.

  15. A SPICE model for a phase-change memory cell based on the analytical conductivity model

    Science.gov (United States)

    Yiqun, Wei; Xinnan, Lin; Yuchao, Jia; Xiaole, Cui; Jin, He; Xing, Zhang

    2012-11-01

    By way of periphery circuit design of the phase-change memory, it is necessary to present an accurate compact model of a phase-change memory cell for the circuit simulation. Compared with the present model, the model presented in this work includes an analytical conductivity model, which is deduced by means of the carrier transport theory instead of the fitting model based on the measurement. In addition, this model includes an analytical temperature model based on the 1D heat-transfer equation and the phase-transition dynamic model based on the JMA equation to simulate the phase-change process. The above models for phase-change memory are integrated by using Verilog-A language, and results show that this model is able to simulate the I-V characteristics and the programming characteristics accurately.

  16. Default cycle phases determined after modifying discrete DNA sequences in plant cells

    Energy Technology Data Exchange (ETDEWEB)

    Sans, J.; Leyton, C. [Universidad de Chile, Santiago (Chile). Facultad de Medicina; Gimenez-Abian, M.I.; Gimenez-Abian, J.F.; Aller, P.; De La Torre, C. [Centro de Investigaciones Biologicas, CSIC, Madrid (Spain)

    1997-02-01

    After bromosubstituting DNA sequences replicated in the first, second, or third part of the S phase, in Allium cepa L. meristematic cells, radiation at 313 nm wavelength under anoxia allowed ascription of different sequences to both the positive and negative regulation of some cycle phase transitions. The present report shows that the radiation forced cells in late G{sub 1} phase to advance into S, while those in G{sub 2} remained in G{sub 2} and cells in prophase returned to G{sub 2} when both sets of sequences involved in the positive and negative controls were bromosubstituted and later irradiated. In this way, not only G{sub 2} but also the S phase behaved as cycle phases where cells accumulated by default when signals of different sign functionally cancelled out. The treatment did not halt the rates of replication or transcription of plant bromosubstituted DNA. The irradiation under hypoxia apparently prevents the binding of regulatory proteins to Br-DNA. (author).

  17. Contrasting quiescent G0 phase with mitotic cell cycling in the mouse immune system.

    Directory of Open Access Journals (Sweden)

    Michio Tomura

    Full Text Available A transgenic mouse line expressing Fucci (fluorescent ubiquitination-based cell-cycle indicator probes allows us to monitor the cell cycle in the hematopoietic system. Two populations with high and low intensities of Fucci signals for Cdt1(30/120 accumulation were identified by FACS analysis, and these correspond to quiescent G0 and cycling G1 cells, respectively. We observed the transition of immune cells between quiescent and proliferative phases in lymphoid organs during differentiation and immune responses.

  18. Holocene aeolian sediments on the NE Tibetan Plateau

    Science.gov (United States)

    Stauch, G.; Lehmkuhl, F.; Hilgers, A.; Zhao, H.

    2012-04-01

    The semiarid climate of the northeastern Tibetan Plateau supports the formation of different types of aeolian sediments and landforms during the Holocene. Aeolians silts and sands in the catchment of the Donggi Cona in an elevation above 4000m to 4800 m asl reflect variable climate conditions during that time as well as different sediment sources. Based on 51 OSL datings and catchment wide geomorphological mapping a complex pattern of long and short distance sediment transport has been reconstructed. Only few aeolian archives are preserved from the late Pleistocene in this mountain environment indicating cold and dry climate conditions which prevented a continuous accumulation. During the early Holocene a phase of increased aeolian sedimentation of sand at the slopes of the mountains has been reconstructed. The sand originated from a large alluvial fan which was highly active during the Pleistocene. In addition, a thin loess cover is preserved at a few sites in the neighboring mountains ranges. The sedimentation of the loess started around 2000 years later than the sedimentation of the sand at the foot slope. Both archives are related to an increase in precipitation at the northern margin of the Tibetan Plateau which was related to a strengthening of the Asian Monsoon during that time. The wetter climate conditions favored the development of a vegetation cover which leads to the trapping and fixation of the aeolian sediments. However, with a further strengthening of the Monsoon systems these archives subsequently eroded due to higher run off and accumulated as colluvial and fluvial deposits in the basins. These phase lasted until 6 ka. A second aeolian period started at around 3 ka with the formation new dunes in the basins. This period can be associated with dry and cold climate of the late Holocene supporting the reactivation of the sand in the area. This might be further enhanced by an increased human impact by grazing during the late Holocene and resulting

  19. Enhanced viral production and virus-mediated mortality of bacterioplankton in a natural iron-fertilized bloom event above the Kerguelen Plateau

    Directory of Open Access Journals (Sweden)

    A. Malits

    2014-07-01

    Full Text Available Above the Kerguelen Plateau in the Southern Ocean natural iron fertilization sustains a large phytoplankton bloom over three months during austral summer. During the KEOPS1 project (KErguelen Ocean and Plateau compared Study1 we sampled this phytoplankton bloom during its declining phase along with the surrounding HNLC waters to study the effect of natural iron fertilization on the role of viruses in the microbial food web. Bacterial and viral abundances were 1.7 and 2.1 times, respectively, higher within the bloom than in HNLC waters. Viral production and virus-mediated mortality of bacterioplankton was 4.1 and 4.9 times, respectively, higher in the bloom, while the fraction of infected cells (FIC and the fraction of lysogenic cells (FLC showed no significant differences between environments. The present study suggests viruses to be more important for bacterial mortality within the bloom and dominate over protozoan grazing during the late bloom phase. As a consequence, at least at a late bloom stage, viral lysis shunts part of the photosynthetically fixed carbon in iron-fertilized regions into the dissolved organic matter (DOM pool with potentially less particulate organic carbon transfered to larger members of the food web or exported.

  20. Enhanced viral production and virus-mediated mortality of bacterioplankton in a natural iron-fertilized bloom event above the Kerguelen Plateau

    Science.gov (United States)

    Malits, A.; Christaki, U.; Obernosterer, I.; Weinbauer, M. G.

    2014-12-01

    Above the Kerguelen Plateau in the Southern Ocean natural iron fertilization sustains a large phytoplankton bloom over 3 months during austral summer. During the KEOPS1 project (KErguelen Ocean and Plateau compared Study1) we sampled this phytoplankton bloom during its declining phase along with the surrounding high-nutrient-low-chlorophyll (HNLC) waters to study the effect of natural iron fertilization on the role of viruses in the microbial food web. Bacterial and viral abundances were 1.7 and 2.1 times, respectively, higher within the bloom than in HNLC waters. Viral production and virus-mediated mortality of bacterioplankton were 4.1 and 4.9 times, respectively, higher in the bloom, while the fraction of infected cells (FIC) and the fraction of lysogenic cells (FLC) showed no significant differences between environments. The present study suggests viruses to be more important for bacterial mortality within the bloom and dominate over grazing of heterotrophic nanoflagellates (HNFs) during the late bloom phase. As a consequence, at least at a late bloom stage, viral lysis shunts part of the photosynthetically fixed carbon in iron-fertilized regions into the dissolved organic matter (DOM) pool with potentially less particulate organic carbon transferred to larger members of the food web or exported.

  1. Constraining properties of GRB magnetar central engines using the observed plateau luminosity and duration correlation

    CERN Document Server

    Rowlinson, A; Dainotti, M; O'Brien, P T; Wijers, R A M J; van der Horst, A J

    2014-01-01

    An intrinsic correlation has been identified between the luminosity and duration of plateaus in the X-ray afterglows of Gamma-Ray Bursts (GRBs; Dainotti et al. 2008), suggesting a central engine origin. The magnetar central engine model predicts an observable plateau phase, with plateau durations and luminosities being determined by the magnetic fields and spin periods of the newly formed magnetar. This paper analytically shows that the magnetar central engine model can explain, within the 1$\\sigma$ uncertainties, the correlation between plateau luminosity and duration. The observed scatter in the correlation most likely originates in the spread of initial spin periods of the newly formed magnetar and provides an estimate of the maximum spin period of ~35 ms (assuming a constant mass, efficiency and beaming across the GRB sample). Additionally, by combining the observed data and simulations, we show that the magnetar emission is most likely narrowly beamed and has $\\lesssim$20% efficiency in conversion of rot...

  2. Nuclear vasohibin-2 promotes cell proliferation by inducing G0/G1 to S phase progression.

    Science.gov (United States)

    Ge, Qianqian; Zhou, Jia; Tu, Min; Xue, Xiaofeng; Li, Zhanjun; Lu, Zipeng; Wei, Jishu; Song, Guoxin; Chen, Jianmin; Guo, Feng; Jiang, Kuirong; Miao, Yi; Gao, Wentao

    2015-09-01

    As a member of the vasohibin (VASH2) family, VASH2 is localized intracellularly as a nuclear and cytoplasmic type. Cytoplasmic VASH2 is associated with carcinoma angiogenesis and malignant transformation and promotes cancer growth. However, the function of nuclear VASH2 has yet to be investigated. The aim of the present study was to detect the nuclear VASH2 expression profile in human organs and tissues by protein microarray technique. To examine the function of nuclear VASH2, we analyzed the relationship between nuclear VASH2 and Ki-67, and stably constructed VASH2 overexpression and knockdown in LO2 and HepG2 cell lines, based on a previous study in hepatic cells. The study was conducted using bromodeoxyuridine, immunofluorescent staining, western blot analysis and flow cytometry. Nuclear VASH2 was highly expressed in actively dividing cells in normal and cancer tissues. There was a significant positive correlation between nuclear VASH2 and Ki-67, indicating that nuclear VASH2 positively correlated with cell proliferation in normal and cancer tissues. The bromodeoxyuridine (BrdU) proliferation test showed that nuclear VASH2 increased the S-phase population and promoted cell proliferation, while VASH2 knockdown reduced BrdU absorbance. Cell cycle analysis revealed that nuclear VASH2 overexpression increased the S-phase population in LO2 and HepG2 cells, while nuclear VASH2 knockdown reduced the S-phase population and increased the G0/G1 population. The findings of this study challenge the classic view of VASH2, which was previously reported as an angiogenesis factor. Furthermore, to the best of our knowledge, these results are the first clinical data indicating that nuclear VASH2, but not cytoplasmic VASH2, promotes cell proliferation by driving the cell cycle from the G0/G1 to S phase.

  3. Phase precession in hippocampal interneurons showing strong functional coupling to individual pyramidal cells.

    Science.gov (United States)

    Maurer, Andrew P; Cowen, Stephen L; Burke, Sara N; Barnes, Carol A; McNaughton, Bruce L

    2006-12-27

    Although hippocampal interneurons typically do not show discrete regions of elevated firing in an environment, such as seen in pyramidal cell place fields, they do exhibit significant spatial modulation (McNaughton et al., 1983a). Strong monosynaptic coupling between pyramidal neurons and nearby interneurons in the CA1 stratum pyramidale has been strongly implicated on the basis of significant, short-latency peaks in cross-correlogram plots (Csicsvari et al., 1998). Furthermore, interneurons receiving a putative monosynaptic connection from a simultaneously recorded pyramidal cell appear to inherit the spatial modulation of the latter (Marshall et al., 2002). Buzsaki and colleagues hypothesize that interneurons may also adopt the firing phase dynamics of their afferent place cells, which show a phase shift relative to the hippocampal theta rhythm as a rat passes through the place field ("phase precession"). This study confirms and extends the previous reports by showing that interneurons in the dorsal and middle hippocampus with putative monosynaptic connections with place cells recorded on the same tetrode share other properties with their pyramidal cell afferents, including the spatial scale of the place field of pyramidal cell, a characteristic of the septotemporal level of the hippocampus from which the cells are recorded, and the rate of phase precession, which is slower in middle regions. Furthermore, variations in pyramidal cell place field scale within each septotemporal level attributable to task variations are similarly associated with variations in interneuron place field scale. The available data strongly suggest that spatial selectivity of CA1 stratum pyramidale interneurons is inherited from a small cluster of local pyramidal cells and is not a consequence of spatially selective synaptic input from CA3 or other sources.

  4. Magnetic shielding accelerates the proliferation of human neuroblastoma cell by promoting G1-phase progression.

    Directory of Open Access Journals (Sweden)

    Wei-chuan Mo

    Full Text Available Organisms have been exposed to the geomagnetic field (GMF throughout evolutionary history. Exposure to the hypomagnetic field (HMF by deep magnetic shielding has recently been suggested to have a negative effect on the structure and function of the central nervous system, particularly during early development. Although changes in cell growth and differentiation have been observed in the HMF, the effects of the HMF on cell cycle progression still remain unclear. Here we show that continuous HMF exposure significantly increases the proliferation of human neuroblastoma (SH-SY5Y cells. The acceleration of proliferation results from a forward shift of the cell cycle in G1-phase. The G2/M-phase progression is not affected in the HMF. Our data is the first to demonstrate that the HMF can stimulate the proliferation of SH-SY5Y cells by promoting cell cycle progression in the G1-phase. This provides a novel way to study the mechanism of cells in response to changes of environmental magnetic field including the GMF.

  5. Magnetic shielding accelerates the proliferation of human neuroblastoma cell by promoting G1-phase progression.

    Science.gov (United States)

    Mo, Wei-chuan; Zhang, Zi-jian; Liu, Ying; Bartlett, Perry F; He, Rong-qiao

    2013-01-01

    Organisms have been exposed to the geomagnetic field (GMF) throughout evolutionary history. Exposure to the hypomagnetic field (HMF) by deep magnetic shielding has recently been suggested to have a negative effect on the structure and function of the central nervous system, particularly during early development. Although changes in cell growth and differentiation have been observed in the HMF, the effects of the HMF on cell cycle progression still remain unclear. Here we show that continuous HMF exposure significantly increases the proliferation of human neuroblastoma (SH-SY5Y) cells. The acceleration of proliferation results from a forward shift of the cell cycle in G1-phase. The G2/M-phase progression is not affected in the HMF. Our data is the first to demonstrate that the HMF can stimulate the proliferation of SH-SY5Y cells by promoting cell cycle progression in the G1-phase. This provides a novel way to study the mechanism of cells in response to changes of environmental magnetic field including the GMF.

  6. Optimization of solar cells for air mass zero operation and study of solar cells at high temperatures, phase 4

    Science.gov (United States)

    Hovel, H. J.; Woodall, J. M.

    1980-01-01

    The Pd contact to GaAs was studied using backscattering, Auger analysis, and sheet resistance measurements. Several metallurgical phases were present at low temperatures, but PdGa was the dominant phase in samples annealed at 500 C. Ti/Pd/Ag contacts appeared to have the lowest contact resistance. Etchback epitaxy (EBE) was compared to saturated melt epitaxy (SME) method of growing liquid phase epitaxial layers. The SME method resulted in a lower density of Ga microdroplets in the grown layer, although the best solar cells were made by the EBE method. Photoluminescence was developed as a tool for contactless analysis of GaAs cells. Efficiencies of over 8 percent were measured at 250 C.

  7. A phase unwrapping algorithm based on Branch cuts for living cell's interference pattern

    Science.gov (United States)

    Wang, Meng; Xia, Wang; Schmidt, Greg; Moore, Duncan T.; McGrath, James L.

    2011-06-01

    Fibroblast is the main part in the loose connective tissue and differentiates from the mesenchymal cell when it is in embryo. It exhibits highly reproducible growth kinetics and reproducible healing dynamics in the scratch-wound assay and the height of it could show this prediction. In order to measure the height of these cells, we construct an interferometer measuration system. As we all know, the interference pattern should be unwrapped first, there are plenty of methods that are under research. In this paper we want to find out a typical methods that could be used in living cell's interference pattern during image processing, and also we can get the conclusion that how to use the method and why it is fit to unwrap the phase of cells. There are mainly three parts in this paper: Firstly, we have designed an Interference system which can be used to get the interference pattern, here we used multiphase interference microscope to measure the cell height. Secondly, a typical method which is based on Goldstein's branch cuts algorithm were used to guide the way that how the phase is unwrapped, this method is the most efficient way to phase unwrapping, and it could induct the unwrapping path through using the branch cut method which could get rid of the residues as much as it could be. As a comparison, we also used some other methods to find different results. Such as the quality-guided path following phase unwrapping; and the Costantini phase unwrapping. Finally, we analyzed the results of the three-dimensional model of the cell surface topography, as a result of the various noises during the experiment, all these unwrapping methods above can't eliminate all the residues and noises, but compared with the other results, the Goldstein's branch cut method has the fittest advantages, it gives the most fluent topography of the living cells.

  8. Current Progresses in Study of Impacts of the Tibetan Plateau on Asian Summer Climate

    Institute of Scientific and Technical Information of China (English)

    WU Guoxiong; MAO Jiangyu; DUAN Anmin; ZHANG Qiong

    2006-01-01

    The current progresses in the study of impacts of the Tibetan Plateau on Asian summer climate in the last decade are reviewed. By analyzing evolution of the transitional zone between westerly to the north and easterly to the south (WEB), it is shown that due to the strong heating over the Tibetan Plateau in spring, the overturning in the prevailing wind direction from easterly in winter to westerly in summer occurs firstly over the eastern Bay of Bengal (BOB), accompanied with vigorous convective precipitation to its east. The area between eastern BOB and western Indo-China Peninsula thus becomes the area with the earliest onset of Asian monsoon, which may be referred as BOB monsoon in short. It is shown that the summertime circulations triggered by the thermal forcing of the Iranian Plateau and the Tibetan Plateau are embedded in phase with the continental-scale circulation forced by the diabatic heating over the Eurasian Continent. As a result, the East Asian summer monsoon is intensified and the drought climate over the western and central Asian areas is enhanced. Together with perturbations triggered by the Tibetan Plateau,the above scenarios and the associated heating have important influences on the climate patterns over Asia.Furthermore, the characteristics of the Tibetan mode of the summertime South Asian high are compared with those of Iranian mode. Results demonstrate that corresponding to each of the bimodality of the South Asian high, the rainfall anomaly distributions over Asia exhibit different patterns.

  9. 200-kg large explosive detonation facing 50-km thick crust beneath west Qinling, northeastern Tibetan plateau

    Institute of Scientific and Technical Information of China (English)

    Qiusheng Li; Rui Gao; Haiyan Wang; Jisheng Zhang; Zhanwu Lu; Pengwu Li; Ye Guan; Rizheng He

    2009-01-01

    It is difficult to acquire deep seismic reflection profiles on land using the standard oil-industry acquisition pa-rameters. This is especially true over much of Tibetan plateau not only because of severe topography and rapid variation of both velocity and thickness of near-surface layer, but also strong attenuation of seismic wave through the thickest crust of the Earth. Large explosive sources had been successfully detonated in US, but its application in Tibetan plateau rarely has an example of good quality. Presented herein is the data of a 200-kg single shot we recorded in west Qinling, northeastern Ti-betan plateau. The shot gather data with phenomenal signal-to-noise ratios illustrate the energy of the ProP phase. Although the observations are only limited to the northeastern Tibetan plateau and thus cannot comprise an exhaustive study, they nev-ertheless suggest that large explosions may be a useful exploration tool in Tibetan Plateau where standard seismic sources and profiling methods fail to produce adequate data of low crust.

  10. Cell sheets image validation of phase-diversity homodyne OCT and effect of the light irradiation on cells

    Science.gov (United States)

    Senda, Naoko; Osawa, Kentaro

    2016-04-01

    Optical coherence tomography (OCT) is one of powerful 3D tissue imaging tools with no fluorescence staining. We have reported that Phase-Diversity Homodyne OCT developed in Hitachi could be useful for non-invasive regeneration tissue evaluation test. The OCT enables cell imaging because of high resolution (axial resolution; ~2.6 μm, lateral resolution; ~1 μm, in the air), whereas conventional OCT was not used for cell imaging because of low resolution (10~20 μm). Furthermore, the OCT has advantage over other 3D imaging devices in cost because the light source and the objective were originally used as an optical pickup of compact disc. In this report, we aimed to assess effectiveness and safety of Phase-Diversity Homodyne OCT cell imaging. Effectiveness of OCT was evaluated by imaging a living cell sheet of human oral mucosal epithelial cells. OCT images were compared with reflection confocal microscopy (RCM) images, because confocal optical system is the highest resolution (<1 μm) 3D in vivo imaging technique. Similar nuclei images were confirmed with OCT and RCM, which suggested the OCT has enough resolution to image nuclei inside a cell sheet. Degree of differentiation could be estimated using OCT images, which becomes possible because the size of cells depends on distribution of differentiation. Effect of the OCT light irradiation on cells was studied using NIH/3T3 cells. Light irradiation, the exposure amount of which is equivalent to OCT, had no impact on cell shape, cell viability, and proliferation rate. It suggested that the light irradiation has no cell damage under the condition.

  11. Morphology Evolution of High Efficiency Perovskite Solar Cells via Vapor Induced Intermediate Phases.

    Science.gov (United States)

    Zuo, Lijian; Dong, Shiqi; De Marco, Nicholas; Hsieh, Yao-Tsung; Bae, Sang-Hoon; Sun, Pengyu; Yang, Yang

    2016-12-07

    Morphology is critical component to achieve high device performance hybrid perovskite solar cells. Here, we develop a vapor induced intermediate phase (VIP) strategy to manipulate the morphology of perovskite films. By exposing the perovskite precursor films to different saturated solvent vapor atmospheres, e.g., dimethylformamide and dimethylsufoxide, dramatic film morphological evolution occurs, associated with the formation of different intermediate phases. We observe that the crystallization kinetics is significantly altered due to the formation of these intermediate phases, yielding highly crystalline perovskite films with less defect states and high carrier lifetimes. The perovskite solar cells with the reconstructed films exhibits the highest power conversion efficiency (PCE) up to 19.2% under 1 sun AM 1.5G irradiance, which is among the highest planar heterojunction perovskite solar cells. Also, the perovskite solar cells with VIP processing shows less hysteresis behavior and a stabilized power output over 18%. Our work opens up a new direction for morphology control through intermediate phase formation, and paves the way toward further enhancing the device performances of perovskite solar cells.

  12. Quercetin arrests G2/M phase and induces caspase-dependent cell death in U937 cells.

    Science.gov (United States)

    Lee, Tae-Jin; Kim, On Hee; Kim, Yeoun Hee; Lim, Jun Hee; Kim, Shin; Park, Jong-Wook; Kwon, Taeg Kyu

    2006-08-28

    Quercetin, a natural product derived from grapes, has been shown to prevent carcinogenesis in murine models. We report here that quercetin induces anti-proliferation and arrests G2/M phase in U937 cells. The G2/M phase accumulation was accompanied by an increase in the level of the cyclin B. In contrast, the level of the cyclin D, cyclin E, E2F1, and E2F2 was marked decreased in quercetin-treated U937 cells. Removal of quercetin from the culture medium stimulates U937 cells to synchronously re-enter the cell cycle, decrease expression level of cyclin B, and increased the expression level of cyclin D and cyclin E. These data demonstrate that quercetin causes reversible G2/M phase arrest, which was related with dramatic changes in the level of cyclin B, cyclin D, and cyclin E. Quercetin-induced down-regulation of cyclin D and cyclin E was associated with suppression of transcriptional levels but not protein stability. In addition, quercetin-treated U937 cells showed DNA fragmentation, increased sub-G1 population, and generated a 60kDa cleavage product of PLC-gamma1 in a dose-dependent manner, which were significantly inhibited by z-VAD-fmk. These data clearly indicate that quercetin-induced apoptosis is associated with caspase activation. In summary, the growth inhibition of the quercetin is highly related to cell cycle arrest at the G2/M phase and induction of caspase-dependent apoptosis in human promonocytic U937 cells.

  13. Capture of circulating tumor cells using photoacoustic flowmetry and two phase flow.

    Science.gov (United States)

    O'Brien, Christine M; Rood, Kyle D; Bhattacharyya, Kiran; DeSouza, Thiago; Sengupta, Shramik; Gupta, Sagar K; Mosley, Jeffrey D; Goldschmidt, Benjamin S; Sharma, Nikhilesh; Viator, John A

    2012-06-01

    Melanoma is the deadliest form of skin cancer, yet current diagnostic methods are unable to detect early onset of metastatic disease. Patients must wait until macroscopic secondary tumors form before malignancy can be diagnosed and treatment prescribed. Detection of cells that have broken off the original tumor and travel through the blood or lymph system can provide data for diagnosing and monitoring metastatic disease. By irradiating enriched blood samples spiked with cultured melanoma cells with nanosecond duration laser light, we induced photoacoustic responses in the pigmented cells. Thus, we can detect and enumerate melanoma cells in blood samples to demonstrate a paradigm for a photoacoustic flow cytometer. Furthermore, we capture the melanoma cells using microfluidic two phase flow, a technique that separates a continuous flow into alternating microslugs of air and blood cell suspension. Each slug of blood cells is tested for the presence of melanoma. Slugs that are positive for melanoma, indicated by photoacoustic waves, are separated from the cytometer for further purification and isolation of the melanoma cell. In this paper, we evaluate the two phase photoacoustic flow cytometer for its ability to detect and capture metastatic melanoma cells in blood.

  14. Effect of platelet lysate on human cells involved in different phases of wound healing.

    Science.gov (United States)

    Barsotti, Maria Chiara; Chiara Barsotti, Maria; Losi, Paola; Briganti, Enrica; Sanguinetti, Elena; Magera, Angela; Al Kayal, Tamer; Feriani, Roberto; Di Stefano, Rossella; Soldani, Giorgio

    2013-01-01

    Platelets are rich in mediators able to positively affect cell activity in wound healing. Aim of this study was to characterize the effect of different concentrations of human pooled allogeneic platelet lysate on human cells involved in the different phases of wound healing (inflammatory phase, angiogenesis, extracellular matrix secretion and epithelialization). Platelet lysate effect was studied on endothelial cells, monocytes, fibroblasts and keratinocytes, in terms of viability and proliferation, migration, angiogenesis, tissue repair pathway activation (ERK1/2) and inflammatory response evaluation (NFκB). Results were compared both with basal medium and with a positive control containing serum and growth factors. Platelet lysate induced viability and proliferation at the highest concentrations tested (10% and 20% v/v). Whereas both platelet lysate concentrations increased cell migration, only 20% platelet lysate was able to significantly promote angiogenic activity (pwound healing.

  15. Programming power reduction in confined phase change memory cells with titanium dioxide clad layer

    Science.gov (United States)

    Chen, Liangliang; Zhang, Zhonghua; Song, Sannian; Song, Zhitang; Zheng, Qianqian; Zhang, Xin; Zhang, Juan; Zheng, Wanting; Shao, Hehong; Zhu, Xiuwei; Yu, Wenlei

    2017-01-01

    A confined structure phase change memory (PCM) cell has been fabricated based on the focused-ion beam technique. Furthermore, the titanium dioxide clad layer was proposed for promoting the temperature rise in the Ge0.61Sb2Te layer that causes the reduction in the reset voltage and current compared to the phase change memory cell without clad layer. Theoretical thermal simulation and calculation for the reset process are conducted to analyze the thermal effect of the titanium dioxide heating layer. The improved performance of the PCM cell with dioxide clad layer can be attributed to the fact that the buffer layer not only acted as heating layer but also efficiently reduced the cell dissipated power.

  16. The Hikurangi Plateau: Tectonic Ricochet and Accretion

    Science.gov (United States)

    Willis, David; Moresi, Louis; Betts, Peter; Whittaker, Joanne

    2015-04-01

    80 million years between interactions with different subduction systems provided time for the Hikurangi Plateau and Pacific Ocean lithosphere to cool, densify and strengthen. Neogene subduction of the Hikurangi Plateau occurring orthogonal to its Cretaceous predecessor, provides a unique opportunity to explore how changes to the physical properties of oceanic lithosphere affect subduction dynamics. We used Underworld to build mechanically consistent collision models to understand the dynamics of the two Hikurangi collisions. The Hikurangi Plateau is a ~112 Ma, 15km thick oceanic plateau that has been entrained by subduction zones immediately preceding the final break-up of Eastern Gondwana and currently within the active Hikurangi Margin. We explore why attempted subduction of the plateau has resulted in vastly different dynamics on two separate occasions. Slab break-off occured during the collision with Gondwana, currently there is apparent subduction of the plateau underneath New Zealand. At ~100Ma the young, hot Hikurangi Plateau, positively buoyant with respect to the underlying mantle, impacted a Gondwana Margin under rapid extension after the subduction of an mid-ocean ridge 10-15Ma earlier. Modelling of plateaus within young oceanic crust indicates that subduction of the thickened crust was unlikely to occur. Frontal accretion of the plateau and accompanying slab break-off is expected to have occured rapidly after its arrival. The weak, young slab was susceptible to lateral propagation of the ~1500 km window opened by the collision, and break-off would have progressed along the subduction zone inhibiting the "step-back" of the trench seen in older plates. Slab break-off coincided with a world-wide reorganisation of plate velocites, and orogenic collapse along the Gondwana margin characterised by rapid extension and thinning of the over-riding continental plate from ~60 to 30km. Following extension, Zealandia migrated to the NW until the Miocene allowing the

  17. Optical Turbulence above the Internal Antarctic Plateau

    CERN Document Server

    Masciadri, E; Hagelin, S; Moigne, P Le; Noilhan, J

    2010-01-01

    The internal antarctic plateau revealed in the last years to be a site with interesting potentialities for the astronomical applications due to the extreme dryness and low temperatures, the typical high altitude of the plateau, the weak level of turbulence in the free atmosphere down to a just few tens of meters from the ground and the thin optical turbulence layer developed at the ground. The main goal of a site testing assessment above the internal antarctic plateau is to characterize the site (optical turbulence and classical meteorological parameters) and to quantify which is the gain we might obtain with respect to equivalent astronomical observations done above mid-latitude sites to support plans for future astronomical facilities. Our group is involved, since a few years, in studies related to the assessment of this site for astronomical applications that include the characterization of the meteorological parameters and optical turbulence provided by general circulation models as well as mesoscale atmo...

  18. Genome-wide copy number profiling of single cells in S-phase reveals DNA-replication domains.

    Science.gov (United States)

    Van der Aa, Niels; Cheng, Jiqiu; Mateiu, Ligia; Zamani Esteki, Masoud; Kumar, Parveen; Dimitriadou, Eftychia; Vanneste, Evelyne; Moreau, Yves; Vermeesch, Joris Robert; Voet, Thierry

    2013-04-01

    Single-cell genomics is revolutionizing basic genome research and clinical genetic diagnosis. However, none of the current research or clinical methods for single-cell analysis distinguishes between the analysis of a cell in G1-, S- or G2/M-phase of the cell cycle. Here, we demonstrate by means of array comparative genomic hybridization that charting the DNA copy number landscape of a cell in S-phase requires conceptually different approaches to that of a cell in G1- or G2/M-phase. Remarkably, despite single-cell whole-genome amplification artifacts, the log2 intensity ratios of single S-phase cells oscillate according to early and late replication domains, which in turn leads to the detection of significantly more DNA imbalances when compared with a cell in G1- or G2/M-phase. Although these DNA imbalances may, on the one hand, be falsely interpreted as genuine structural aberrations in the S-phase cell's copy number profile and hence lead to misdiagnosis, on the other hand, the ability to detect replication domains genome wide in one cell has important applications in DNA-replication research. Genome-wide cell-type-specific early and late replicating domains have been identified by analyses of DNA from populations of cells, but cell-to-cell differences in DNA replication may be important in genome stability, disease aetiology and various other cellular processes.

  19. Plasmid DNA Supercoiling and Gyrase Activity in Escherichia coli Wild-Type and rpoS Stationary-Phase Cells

    Science.gov (United States)

    Reyes-Domínguez, Yazmid; Contreras-Ferrat, Gabriel; Ramírez-Santos, Jesús; Membrillo-Hernández, Jorge; Gómez-Eichelmann, M. Carmen

    2003-01-01

    Stationary-phase cells displayed a distribution of relaxed plasmids and had the ability to recover plasmid supercoiling as soon as nutrients became available. Preexisting gyrase molecules in these cells were responsible for this recovery. Stationary-phase rpoS cells showed a bimodal distribution of plasmids and failed to supercoil plasmids after the addition of nutrients, suggesting that rpoS plays a role in the regulation of plasmid topology during the stationary phase. PMID:12533486

  20. Tectonomagmatic Associations on the Central Andean Plateau

    Science.gov (United States)

    de Silva, S. L.; Viramonte, J. G.

    2012-12-01

    The Neogene evolution of the Central Andes is characterized by a strong association between plate convergence, mountain building and plateau formation, and magmatism. Plateau uplift by crustal shortening and thickening in the lower crust is broadly coincident with large scale silicic magmatism defined by the Neogene Central Andean ignimbrite province. Of particular interest here are the spatiotemporal correlations between silicic magmatism and tectonic evolution of the Altiplano-Puna plateau. Although magmatism is driven by the subduction-related flux from mantle to crust, the shift to "crustal" magmatism as indicated by elevated crustal isotopic indices after ~10Ma suggests a link between crustal thickening, plateau formation and silicic magmatism. In particular, elevated geotherms associated with crustal thickening and enhanced mantle flux associated with lithospheric delamination may have played a role in thermally preparing the Central Andean crust for enhanced silicic magma production during the extensive Neogene ignimbrite flare-up. Emplacement of these magmas in the upper crust throughout the Neogene may have fuelled a period of significant interaction between magmatism and tectonism on the plateau. With particular reference to the 21° to 24°S segment of the Central Andes, spatial and structural coincidence of calderas of the Altiplano Puna Volcanic Complex with the NW-SE striking Calama-Olacapata-El Toro fault zone suggests significant tectonomagmatic interaction. Location of calderas suggest that these regional faults focused magma intrusion and storage, while spatially and temporally correlated eruption pulses connote a tectonic control. Indeed, current thermomechanical models of magma chamber development and eruption triggering promote a role for external triggering of "perched" upper crustal magma chambers. This might have been achieved by melt-enhanced deformation, or alternatively, significant uplift (~1km) associated with the development of large

  1. Peopling the Tibetan plateau: insights from archaeology.

    Science.gov (United States)

    Aldenderfer, Mark

    2011-01-01

    Recent studies of the genome of modern Tibetans have revealed the existence of genes thought to provide an adaptive advantage for life at high elevation. Extrapolating from this discovery, some researchers now argue that a Tibetan-Han split occurred no more than 2750 yr ago. This date is implausible, and in this paper I review the archaeological data from the Tibetan plateau as one means by which to examine the veracity of this assertion. Following a review of the general state of knowledge of Tibetan prehistory, which is unfortunately only at its beginnings, I first examine the data that speak to the initial peopling of the plateau and assess the evidence that traces of their presence can be seen in modern Tibetans today. Although the data are sparse, both archaeology and genetics suggest that the plateau was occupied in the Late Pleistocene, perhaps as early as 30,000 yr ago, and that these early peoples have left a genetic signature in modern Tibetans. I then turn to the evidence for later migrations and focus on the question of the timing of the establishment of permanent settled villages on the plateau. Three areas of the plateau-northeastern Qinghai, extreme eastern Tibet, and the Yarlung Tsangpo valley-have evidence of permanent settlements dating from ca. 6500, 5900, and 3750 yr ago, respectively. These data are not consonant with the 2750 yr ago date for the split and suggest at a minimum that the plateau has been occupied substantially longer and, further, that multiple migrations at different times and from different places have created a complex mosaic of population history. © Mary Ann Liebert, Inc.

  2. R-Phycoerythrin Induces SGC-7901 Apoptosis by Arresting Cell Cycle at S Phase.

    Science.gov (United States)

    Tan, Huixin; Gao, Shiyong; Zhuang, Yan; Dong, Yanhong; Guan, Wenhui; Zhang, Kun; Xu, Jian; Cui, Jingru

    2016-09-12

    R-Phycoerythrin (R-PE), one of the chemical constituents of red algae, could produce singlet oxygen upon excitation with the appropriate radiation and possibly be used in photodynamic therapy (PDT) for cancer. Documents reported that R-PE could inhibit cell proliferation in HepG2 and A549 cells, which was significative for cancer therapy. This is due to the fact that R-PE could kill cancer cells directly as well as by PDT. However, little is known about the cytotoxicity of R-PE to the SGC-7901 cell. In this study, it has been found that R-PE could inhibit SGC-7901 proliferation and induce cell apoptosis, which was achieved by arresting the SGC-7901 cell at S phase. CyclinA, CDK2 and CDC25A are proteins associated with the S phase, and it was found that R-PE could increase the expression of cyclin A protein and decrease the expression of CDK2 and CDC25A proteins. Thus, it was concluded that R-PE reduced the CDK2 protein activated through decreasing the CDC25A factor, which reduced the formation of Cyclin-CDK complex. The reduction of Cyclin-CDK complex made the SGC-7901 cells arrest at the S phase. Therefore, R-PE induced apoptosis by arresting the SGC-7901 cell at S phase was successful, which was achieved by the expression of the CDC25A protein, which reduced the CDK2 protein actived and the formation of Cyclin-CDK complex.

  3. Quantitative Phase Imaging Techniques for the Study of Cell Pathophysiology: From Principles to Applications

    Directory of Open Access Journals (Sweden)

    Hyunjoo Park

    2013-03-01

    Full Text Available A cellular-level study of the pathophysiology is crucial for understanding the mechanisms behind human diseases. Recent advances in quantitative phase imaging (QPI techniques show promises for the cellular-level understanding of the pathophysiology of diseases. To provide important insight on how the QPI techniques potentially improve the study of cell pathophysiology, here we present the principles of QPI and highlight some of the recent applications of QPI ranging from cell homeostasis to infectious diseases and cancer.

  4. R-Phycoerythrin Induces SGC-7901 Apoptosis by Arresting Cell Cycle at S Phase

    Science.gov (United States)

    Tan, Huixin; Gao, Shiyong; Zhuang, Yan; Dong, Yanhong; Guan, Wenhui; Zhang, Kun; Xu, Jian; Cui, Jingru

    2016-01-01

    R-Phycoerythrin (R-PE), one of the chemical constituents of red algae, could produce singlet oxygen upon excitation with the appropriate radiation and possibly be used in photodynamic therapy (PDT) for cancer. Documents reported that R-PE could inhibit cell proliferation in HepG2 and A549 cells, which was significative for cancer therapy. This is due to the fact that R-PE could kill cancer cells directly as well as by PDT. However, little is known about the cytotoxicity of R-PE to the SGC-7901 cell. In this study, it has been found that R-PE could inhibit SGC-7901 proliferation and induce cell apoptosis, which was achieved by arresting the SGC-7901 cell at S phase. CyclinA, CDK2 and CDC25A are proteins associated with the S phase, and it was found that R-PE could increase the expression of cyclin A protein and decrease the expression of CDK2 and CDC25A proteins. Thus, it was concluded that R-PE reduced the CDK2 protein activated through decreasing the CDC25A factor, which reduced the formation of Cyclin-CDK complex. The reduction of Cyclin-CDK complex made the SGC-7901 cells arrest at the S phase. Therefore, R-PE induced apoptosis by arresting the SGC-7901 cell at S phase was successful, which was achieved by the expression of the CDC25A protein, which reduced the CDK2 protein actived and the formation of Cyclin-CDK complex. PMID:27626431

  5. R-Phycoerythrin Induces SGC-7901 Apoptosis by Arresting Cell Cycle at S Phase

    Directory of Open Access Journals (Sweden)

    Huixin Tan

    2016-09-01

    Full Text Available R-Phycoerythrin (R-PE, one of the chemical constituents of red algae, could produce singlet oxygen upon excitation with the appropriate radiation and possibly be used in photodynamic therapy (PDT for cancer. Documents reported that R-PE could inhibit cell proliferation in HepG2 and A549 cells, which was significative for cancer therapy. This is due to the fact that R-PE could kill cancer cells directly as well as by PDT. However, little is known about the cytotoxicity of R-PE to the SGC-7901 cell. In this study, it has been found that R-PE could inhibit SGC-7901 proliferation and induce cell apoptosis, which was achieved by arresting the SGC-7901 cell at S phase. CyclinA, CDK2 and CDC25A are proteins associated with the S phase, and it was found that R-PE could increase the expression of cyclin A protein and decrease the expression of CDK2 and CDC25A proteins. Thus, it was concluded that R-PE reduced the CDK2 protein activated through decreasing the CDC25A factor, which reduced the formation of Cyclin-CDK complex. The reduction of Cyclin-CDK complex made the SGC-7901 cells arrest at the S phase. Therefore, R-PE induced apoptosis by arresting the SGC-7901 cell at S phase was successful, which was achieved by the expression of the CDC25A protein, which reduced the CDK2 protein actived and the formation of Cyclin-CDK complex.

  6. U-Pb zircon geochronology and phase equilibria modelling of a mafic eclogite from the Sumdo complex of south-east Tibet: Insights into prograde zircon growth and the assembly of the Tibetan plateau

    Science.gov (United States)

    Weller, O. M.; St-Onge, M. R.; Rayner, N.; Waters, D. J.; Searle, M. P.; Palin, R. M.

    2016-10-01

    The Sumdo complex is a Permian-Triassic eclogitic metamorphic belt in south-east Tibet, which marks the location of a suture zone that separates the northern and southern Lhasa terranes. An integrated geochronological and petrological study of a mafic eclogite from the complex has constrained its tectonometamorphic history and provides a case study of zircon growth in eclogite as a product of prograde dissolution-precipitation. In situ U-Pb geochronology indicates that the eclogite contains a single population of zircon with a crystallisation age of 273.6 ± 2.8 Ma. The morphology and chemistry of the zircon grains are consistent with growth by dissolution-precipitation of protolith magmatic zircon. The presence of zircon grains as inclusions in the cores of peak phases indicates that zircon dissolution-precipitation occurred during prograde metamorphism, and calculated pressure and temperature conditions over which mineral inclusions in zircon are stable suggest that the zircon most likely precipitated at 15.5-16.5 kbar and 500-560 °C. Subsequent peak metamorphism is calculated to have reached pressure-temperature conditions of 27 ± 1 kbar and 670 ± 50 °C. Previous studies, which have documented a range of peak metamorphic conditions from high- to ultrahigh-pressure at c. 266-230 Ma, indicate that the Sumdo complex is a composite belt that experienced protracted eclogite exhumation. The results of this study are consistent with this interpretation, and extend the age range of high-pressure metamorphism in the complex to over 40 Myr. Analysis of published pressure-temperature-time data indicates two systematic behaviours within this spread. First, peak metamorphic temperatures declined over time. Second, eclogite exhumation occurred in two discrete intervals: soon after formation, and during the demise of the subduction zone. The latter behaviour serves as a reminder that eclogite exhumation is the exception rather than the rule.

  7. Physiological electric fields control the G1/S phase cell cycle checkpoint to inhibit endothelial cell proliferation.

    Science.gov (United States)

    Wang, Entong; Yin, Yili; Zhao, Min; Forrester, John V; McCaig, Colin D

    2003-03-01

    Vascular endothelial cell (VEC) proliferation is a key event in angiogenesis and is tightly regulated. Electric potential differences exist around the vascular endothelium and give rise to endogenous electric fields (EFs), whether these EFs influence VEC proliferation is unclear. We exposed cultured VECs to applied EFs of physiological strengths for up to 72 h. EF at 50 or 100 mV/mm did not influence cell proliferation, but at 200 mV/mm, cell density, cell growth rate, and mitosis index decreased significantly. EF-induced reduction in VEC proliferation was not due to increased apoptosis, because caspase apoptosis inhibitor Z-VAD-FMK (20 microM), had no effect on this response. Rather, EF responses were mediated via decreased entry of cells into S phase from G1 phase, as shown by flow cytometry. Western blot showed that EFs decreased G1-specific cyclin E expression and increased cyclin/cyclin-dependent kinase complex inhibitor p27kipl expression. Thus EFs controlled VEC proliferation through induction of cell cycle arrest at G1 by down-regulation of cyclin E expression and up-regulation of p27kipl expression, rather than by promoting apoptosis. If control of the cell cycle by endogenous EFs extends beyond VECs, this would be of widespread biological significance in vivo.

  8. Quantitative phase imaging of cell division in yeast cells and E.coli using digital holographic microscopy

    Science.gov (United States)

    Pandiyan, Vimal Prabhu; John, Renu

    2015-12-01

    Digital holographic microscope (DHM) is an emerging quantitative phase imaging technique with unique imaging scales and resolutions leading to multitude of applications. DHM is promising as a novel investigational and applied tool for cell imaging, studying the morphology and real time dynamics of cells and a number of related applications. The use of numerical propagation and computational digital optics offer unique flexibility to tune the depth of focus, and compensate for image aberrations. In this work, we report imaging the dynamics of cell division in E.coli and yeast cells using a DHM platform. We demonstrate 3-D and depth imaging as well as reconstruction of phase profiles of E.coli and yeast cells using the system. We record a digital hologram of E.coli and yeast cells and reconstruct the image using Fresnel propagation algorithm. We also use aberration compensation algorithms for correcting the aberrations that are introduced by the microscope objective in the object path using linear least square fitting techniques. This work demonstrates the strong potential of a DHM platform in 3-D live cell imaging, fast clinical quantifications and pathological applications.

  9. Modeling the effects of cell cycle M-phase transcriptional inhibition on circadian oscillation.

    Directory of Open Access Journals (Sweden)

    Bin Kang

    2008-03-01

    Full Text Available Circadian clocks are endogenous time-keeping systems that temporally organize biological processes. Gating of cell cycle events by a circadian clock is a universal observation that is currently considered a mechanism serving to protect DNA from diurnal exposure to ultraviolet radiation or other mutagens. In this study, we put forward another possibility: that such gating helps to insulate the circadian clock from perturbations induced by transcriptional inhibition during the M phase of the cell cycle. We introduced a periodic pulse of transcriptional inhibition into a previously published mammalian circadian model and simulated the behavior of the modified model under both constant darkness and light-dark cycle conditions. The simulation results under constant darkness indicated that periodic transcriptional inhibition could entrain/lock the circadian clock just as a light-dark cycle does. At equilibrium states, a transcriptional inhibition pulse of certain periods was always locked close to certain circadian phases where inhibition on Per and Bmal1 mRNA synthesis was most balanced. In a light-dark cycle condition, inhibitions imposed at different parts of a circadian period induced different degrees of perturbation to the circadian clock. When imposed at the middle- or late-night phase, the transcriptional inhibition cycle induced the least perturbations to the circadian clock. The late-night time window of least perturbation overlapped with the experimentally observed time window, where mitosis is most frequent. This supports our hypothesis that the circadian clock gates the cell cycle M phase to certain circadian phases to minimize perturbations induced by the latter. This study reveals the hidden effects of the cell division cycle on the circadian clock and, together with the current picture of genome stability maintenance by circadian gating of cell cycle, provides a more comprehensive understanding of the phenomenon of circading gating of

  10. Modeling the effects of cell cycle M-phase transcriptional inhibition on circadian oscillation.

    Science.gov (United States)

    Kang, Bin; Li, Yuan-Yuan; Chang, Xiao; Liu, Lei; Li, Yi-Xue

    2008-03-28

    Circadian clocks are endogenous time-keeping systems that temporally organize biological processes. Gating of cell cycle events by a circadian clock is a universal observation that is currently considered a mechanism serving to protect DNA from diurnal exposure to ultraviolet radiation or other mutagens. In this study, we put forward another possibility: that such gating helps to insulate the circadian clock from perturbations induced by transcriptional inhibition during the M phase of the cell cycle. We introduced a periodic pulse of transcriptional inhibition into a previously published mammalian circadian model and simulated the behavior of the modified model under both constant darkness and light-dark cycle conditions. The simulation results under constant darkness indicated that periodic transcriptional inhibition could entrain/lock the circadian clock just as a light-dark cycle does. At equilibrium states, a transcriptional inhibition pulse of certain periods was always locked close to certain circadian phases where inhibition on Per and Bmal1 mRNA synthesis was most balanced. In a light-dark cycle condition, inhibitions imposed at different parts of a circadian period induced different degrees of perturbation to the circadian clock. When imposed at the middle- or late-night phase, the transcriptional inhibition cycle induced the least perturbations to the circadian clock. The late-night time window of least perturbation overlapped with the experimentally observed time window, where mitosis is most frequent. This supports our hypothesis that the circadian clock gates the cell cycle M phase to certain circadian phases to minimize perturbations induced by the latter. This study reveals the hidden effects of the cell division cycle on the circadian clock and, together with the current picture of genome stability maintenance by circadian gating of cell cycle, provides a more comprehensive understanding of the phenomenon of circading gating of cell cycle.

  11. Phase resolved and coherence gated en face reflection imaging of multilayered embryonal carcinoma cells

    Science.gov (United States)

    Yamauchi, Toyohiko; Fukami, Tadashi; Iwai, Hidenao; Yamashita, Yutaka

    2012-03-01

    Embryonal carcinoma (EC) cells, which are cell lines derived from teratocarcinomas, have characteristics in common with stem cells and differentiate into many kinds of functional cells. Similar to embryonic stem (ES) cells, undifferentiated EC cells form multi-layered spheroids. In order to visualize the three-dimensional structure of multilayered EC cells without labeling, we employed full-field interference microscopy with the aid of a low-coherence quantitative phase microscope, which is a reflection-type interference microscope employing the digital holographic technique with a low-coherent light source. Owing to the low-coherency of the light-source (halogen lamp), only the light reflected from reflective surface at a specific sectioning height generates an interference image on the CCD camera. P19CL6 EC cells, derived from mouse teratocarcinomas, formed spheroids that are about 50 to 200 micrometers in diameter. Since the height of each cell is around 10 micrometers, it is assumed that each spheroid has 5 to 20 cell layers. The P19CL6 spheroids were imaged in an upright configuration and the horizontally sectioned reflection images of the sample were obtained by sequentially and vertically scanning the zero-path-length height. Our results show the threedimensional structure of the spheroids, in which plasma and nuclear membranes were distinguishably imaged. The results imply that our technique is further capable of imaging induced pluripotent stem (iPS) cells for the assessment of cell properties including their pluripotency.

  12. Determination of phase equilibria in confined systems by open pore cell Monte Carlo method.

    Science.gov (United States)

    Miyahara, Minoru T; Tanaka, Hideki

    2013-02-28

    We present a modification of the molecular dynamics simulation method with a unit pore cell with imaginary gas phase [M. Miyahara, T. Yoshioka, and M. Okazaki, J. Chem. Phys. 106, 8124 (1997)] designed for determination of phase equilibria in nanopores. This new method is based on a Monte Carlo technique and it combines the pore cell, opened to the imaginary gas phase (open pore cell), with a gas cell to measure the equilibrium chemical potential of the confined system. The most striking feature of our new method is that the confined system is steadily led to a thermodynamically stable state by forming concave menisci in the open pore cell. This feature of the open pore cell makes it possible to obtain the equilibrium chemical potential with only a single simulation run, unlike existing simulation methods, which need a number of additional runs. We apply the method to evaluate the equilibrium chemical potentials of confined nitrogen in carbon slit pores and silica cylindrical pores at 77 K, and show that the results are in good agreement with those obtained by two conventional thermodynamic integration methods. Moreover, we also show that the proposed method can be particularly useful for determining vapor-liquid and vapor-solid coexistence curves and the triple point of the confined system.

  13. Electroporation of micro-droplet encapsulated HeLa cells in oil phase

    KAUST Repository

    Xiao, Kang

    2010-08-27

    Electroporation (EP) is a method widely used to introduce foreign genes, drugs or dyes into cells by permeabilizing the plasma membrane with an external electric field. A variety of microfluidic EP devices have been reported so far. However, further integration of prior and posterior EP processes turns out to be very complicated, mainly due to the difficulty of developing an efficient method for precise manipulation of cells in microfluidics. In this study, by means of a T-junction structure within a delicate microfluidic device, we encapsulated HeLa cells in micro-droplet of poration medium in oil phase before EP, which has two advantages: (i) precise control of cell-encapsulating droplets in oil phase is much easier than the control of cell populations or individuals in aqueous buffers; (ii) this can minimize the electrochemical reactions on the electrodes. Finally, we successfully introduced fluorescent dyes into the micro-droplet encapsulated HeLa cells in oil phase. Our results reflected a novel way to realize the integrated biomicrofluidic system for EP. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

  14. Dux4 induces cell cycle arrest at G1 phase through upregulation of p21 expression

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hongliang; Wang, Zhaoxia; Jin, Suqin; Hao, Hongjun [Department of Neurology, Peking University First Hospital, Beijing 100034 (China); Zheng, Lemin [The Institute of Cardiovascular Sciences, Peking University Health Science Center, Key Laboratory of Molecular Cardiovascular Sciences of Education Ministry, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides of Health Ministry, Beijing 100191 (China); Zhou, Boda [The Department of Cardiology, Peking University Third Hospital, Beijing 100191 (China); Zhang, Wei; Lv, He [Department of Neurology, Peking University First Hospital, Beijing 100034 (China); Yuan, Yun, E-mail: yuanyun2002@sohu.com [Department of Neurology, Peking University First Hospital, Beijing 100034 (China)

    2014-03-28

    Highlights: • Dux4 induced TE671 cell proliferation defect and G1 phase arrest. • Dux4 upregulated p21 expression without activating p53. • Silencing p21 rescued Dux4 mediated proliferation defect and cell cycle arrest. • Sp1 binding site was required for Dux4-induced p21 promoter activation. - Abstract: It has been implicated that Dux4 plays crucial roles in development of facioscapulohumeral dystrophy. But the underlying myopathic mechanisms and related down-stream events of this retrogene were far from clear. Here, we reported that overexpression of Dux4 in a cell model TE671 reduced cell proliferation rate, and increased G1 phase accumulation. We also determined the impact of Dux4 on p53/p21 signal pathway, which controls the checkpoint in cell cycle progression. Overexpression of Dux4 increased p21 mRNA and protein level, while expression of p53, phospho-p53 remained unchanged. Silencing p21 rescued Dux4 mediated proliferation defect and cell cycle arrest. Furthermore, we demonstrated that enhanced Dux4 expression increased p21 promoter activity and elevated expression of Sp1 transcription factor. Mutation of Sp1 binding site decreased dux4 induced p21 promoter activation. Chromatin immunoprecipitation (ChIP) assays confirmed the Dux4-induced binding of Sp1 to p21 promoter in vivo. These results suggest that Dux4 might induce proliferation inhibition and G1 phase arrest through upregulation of p21.

  15. The Influence of Low-frequency Oscillation Propagation of the Tibetan Plateau Vortex on Rainstorm Downstream

    Science.gov (United States)

    Xiao, Tiangui; Wang, Chao; La, Jia; Du, Jun; Zhang, Kairong

    2017-04-01

    Based on Tibetan Plateau vortex data, ERA-Interim and NCEP/NCAR reanalysis data, the characteristics of Tibetan Plateau vortex and the relationship with Low-Frequency Oscillation (LFO) from 2003 to 2012 were investigated. The heavy rainstorm occurred in Sichuan from June 29th to July 2nd in 2013, caused by the LFO, was studied. Besides, the signal of LFO, energy transmission and those influence to rainstorm were also investigate. The main conclusions are as follows: (1)Most of Tibetan Plateau vortex generate in eastern plateau, located at Tanggula Mountains, Zaduo, Dege, Qumalai and Qaidam. The moving-out Tibetan Plateau vortex mainly generate in Qumalai and most vortex occurrences during April to September. There are three directions of moving-out vortex paths: northeast, southeast and east. The areas which plateau vortex moving into are mainly distributed in Gansu, Sichuan, Shaanxi and Ningxia. (2)The zonal wind at 500hPa in plateau key region has a significant main 10-30d oscillation, with the secondly significant oscillation in 30-50d and the third in 70-90d. The relative vorticity at 500hPa in plateau key region has a significant main 30-50d oscillations, with the secondly significant oscillation in 10-30d. The 30-50d oscillation phase zone with weak westerly oscillation zone of 500hPa, and the 10-30d oscillation positive phase zone with weak oscillation zone of 500hPa are benefit to vortex generation. The 30-50d oscillation of zonal wind at 500hPa provides necessary circulation background for generation of plateau vortex, and positive phase region of 10-30d oscillation of relative vorticity at 500hPa provide necessary dynamic background conditions for it. (3) Comparing with the high frequency oscillation vortex, 10-25d low-frequency vortex is not significant at 500hPa before merging into the basin vortex. However, after merging into the basin vortex, there is a significant relationship between low-frequency vortex and the process of development, weakening and

  16. Optomechanical properties of cancer cells revealed by light-induced deformation and quantitative phase microscopy

    Science.gov (United States)

    Kastl, Lena; Budde, Björn; Isbach, Michael; Rommel, Christina; Kemper, Björn; Schnekenburger, Jürgen

    2015-05-01

    There is a growing interest in cell biology and clinical diagnostics in label-free, optical techniques as the interaction with the sample is minimized and substances like dyes or fixatives do not affect the investigated cells. Such techniques include digital holographic microscopy (DHM) and the optical stretching by fiber optical two beam traps. DHM enables quantitative phase contrast imaging and thereby the determination of the cellular refractive index, dry mass and the volume, whereas optical cell stretching reveals the deformability of cells. Since optical stretching strongly depends on the optical properties and the shape of the investigated material we combined the usage of fiber optical stretching and DHM for the characterization of pancreatic tumor cells. The risk of tumors is their potential to metastasize, spread through the bloodstream and build distal tumors/metastases. The grade of dedifferentiation in which the cells lose their cell type specific properties is a measure for this metastatic potential. The less differentiated the cells are, the higher is their risk to metastasize. Our results demonstrate that pancreatic tumor cells, which are from the same tumor but vary in their grade of differentiation, show significant differences in their deformability. The retrieved data show that differentiated cells have a higher stiffness than less differentiated cells of the same tumor. Even cells that differ only in the expression of a single tumor suppressor gene which is responsible for cell-cell adhesions can be distinguished by their mechanical properties. Additionally, results from DHM measurements yield that the refractive index shows only few variations, indicating that it does not significantly influence optical cell stretching. The obtained results show a promising new approach for the phenotyping of different cell types, especially in tumor cell characterization and cancer diagnostics.

  17. The Phase Transition of Nematic Liquid Crystal Cells Bounded by Surfactant-Laden Interfaces

    Institute of Scientific and Technical Information of China (English)

    ZENG Ming-Ying; CUI Wei; TAN Xiao-Qin; WU Chen-Xu

    2011-01-01

    @@ Taking into account the surface-coupling strength effect, we discuss the phase transitions of a finite thickness cell bounded by surfactant-laden interfaces in a magnetic field perpendicular to the substrate and it is compared with that of a semi-infinite system.It is found that the larger the thickness, the closer the three-dimensional phase transition surfacc of the finite system to that of the semi-infinite one.The simulation also shows that when a magnetic field is applied to a nematic semi-infinite sample, an orientational phase transition first takes place close to the interface and thcn extends to the inner space as the temperature increases.%Taking into account the surface-coupling strength effect, we discuss the phase transitions of a finite thickness cell bounded by surfactant-laden interfaces in a magnetic field perpendicular to the substrate and it is compared with that of a semi-infinite system. It is found that the larger the thickness, the closer the three-dimensional phase transition surface of the finite system to that of the semi-infinite one. The simulation also shows that when a magnetic field is applied to a nernatic semi-infinite sample, an orientational phase transition first takes place close to the interface and then extends to the inner space as the temperature increases.

  18. Effect of Gas Phase Transport in Molten Carbonate Fuel Cell (I)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C.G.; Lim, H.C. [Korea Electric Power Research Institute, Taejon (Korea)

    1999-07-01

    The mass transfer effect in gas phase of molten carbonate fuel cell (MCFC) has not been profoundly studied. We have tried to investigate it with disturbance of reactant gas flow. An inert gas was added into anode and cathode reactant gas streams, and the resulting voltage shifts were analyzed. The disturbance of reactant gas was carried out at different reactant and inert gas flow rates, and current density. The results express that the anode performance is profoundly influenced by mass transfer in gas phase while the cathode is not. Moreover, the quantitative analysis of mass transfer effect in gas phase was available by means of the inert gas disturbance. The method led to the separate analyses of mass transfer effect in cell. The effects of mass transfer in gas channel and porous electrode regions were measured by changing gas channel depth and electrode thickness. It was found that mass transfer resistance in anode takes place mainly in porous electrode. Meanwhile the voltage shifts in cathode represented both gas and liquid phase mass transfer effect separately. It was also found that the mass transfer resistance in gas phase is insignificant in cathode compared with that in anode. The voltage shift values, which mean mass transfer resistance in liquid phase, depended on oxidant gas composition. It implies that the cathode reaction in MCFC would be an O{sub 2} and CO{sub 2} mixed diffusion control process. (author). 11 refs., 5 figs.

  19. Use of Fluorescence Lifetime Imaging Microscopy (FLIM) as a Timer of Cell Cycle S Phase.

    Science.gov (United States)

    Okkelman, Irina A; Dmitriev, Ruslan I; Foley, Tara; Papkovsky, Dmitri B

    2016-01-01

    Incorporation of thymidine analogues in replicating DNA, coupled with antibody and fluorophore staining, allows analysis of cell proliferation, but is currently limited to monolayer cultures, fixed cells and end-point assays. We describe a simple microscopy imaging method for live real-time analysis of cell proliferation, S phase progression over several division cycles, effects of anti-proliferative drugs and other applications. It is based on the prominent (~ 1.7-fold) quenching of fluorescence lifetime of a common cell-permeable nuclear stain, Hoechst 33342 upon the incorporation of 5-bromo-2'-deoxyuridine (BrdU) in genomic DNA and detection by fluorescence lifetime imaging microscopy (FLIM). We show that quantitative and accurate FLIM technique allows high-content, multi-parametric dynamic analyses, far superior to the intensity-based imaging. We demonstrate its uses with monolayer cell cultures, complex 3D tissue models of tumor cell spheroids and intestinal organoids, and in physiological study with metformin treatment.

  20. Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells

    Science.gov (United States)

    Yuan, Hengguang; Hu, Shanglian; Huang, Peng; Song, Hua; Wang, Kan; Ruan, Jing; He, Rong; Cui, Daxiang

    2011-12-01

    Herein we are the first to report that single-walled carbon nanotubes (SWCNTs) exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS) generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis.

  1. Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells

    Directory of Open Access Journals (Sweden)

    Huang Peng

    2011-01-01

    Full Text Available Abstract Herein we are the first to report that single-walled carbon nanotubes (SWCNTs exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis.

  2. Phase II study of ACNU in non-small-cell lung cancer: EORTC study 08872

    NARCIS (Netherlands)

    A.S.Th. Planting (André); A. Ardizzoni (A.); J. Estapé (J.); G. Giaccone (Giuseppe); G.V. Scagliotti (Giorgio); T.A.W. Splinter (Ted); A. Kirkpatrick (A.); O. Dalesio (O.); J.G. Mcvie (John Gordon)

    1991-01-01

    textabstractA total of 62 patients with metastatic or locally advanced non-small-cell lung cancer were entered in a phase II study of ACNU. Initially, the drug was given i. v. at a dose of 100 mg/m2 every 6 weeks, but due to observed haematological side effects in chemotherapy-pretreated patients,

  3. Two-Phase Flow in Rotating Hele-Shaw Cells with Coriolis Effects

    CERN Document Server

    Escher, Joachim; Walker, Christoph

    2011-01-01

    The free boundary problem of a two phase flow in a rotating Hele-Shaw cell with Coriolis effects is studied. Existence and uniqueness of solutions near spheres is established, and the asymptotic stability and instability of the trivial solution is characterized in dependence on the fluid densities.

  4. Recombinant human interleukin 6 in metastatic renal cell cancer : A phase II trial

    NARCIS (Netherlands)

    Stouthard, JML; Goey, H; deVries, EGE; deMulder, PH; Groenewegen, A; Stoter, G; Sauerwein, HP; Bakker, PJM; Veenhof, CHN

    A phase II trial investigating the anti-tumour effects of recombinant human interleukin 6 (rhlL-6) in patients with metastatic renal cell cancer was carried out. RhIL-6 (150 mu g) was administered as a daily subcutaneous injection for 42 consecutive days on an outpatient basis. Forty-nine patients

  5. Examination of water phase transitions in Loblolly pine and cell wall components by differential scanning calorimetry

    Science.gov (United States)

    Samuel L. Zelinka; Michael J. Lambrecht; Samuel V. Glass; Alex C. Wiedenhoeft; Daniel J. Yelle

    2012-01-01

    This paper examines phase transformations of water in wood and isolated wood cell wall components using differential scanning calorimetry with the purpose of better understanding "Type II water" or "freezable bound water" that has been reported for cellulose and other hydrophilic polymers. Solid loblolly pine (Pinus taeda...

  6. Recombinant human interleukin 6 in metastatic renal cell cancer : A phase II trial

    NARCIS (Netherlands)

    Stouthard, JML; Goey, H; deVries, EGE; deMulder, PH; Groenewegen, A; Stoter, G; Sauerwein, HP; Bakker, PJM; Veenhof, CHN

    1996-01-01

    A phase II trial investigating the anti-tumour effects of recombinant human interleukin 6 (rhlL-6) in patients with metastatic renal cell cancer was carried out. RhIL-6 (150 mu g) was administered as a daily subcutaneous injection for 42 consecutive days on an outpatient basis. Forty-nine patients w

  7. Leukemic phase of anaplastic lymphoma kinase positive, anaplastic large cell lymphoma

    Directory of Open Access Journals (Sweden)

    Vijaya S Gadage

    2011-01-01

    Full Text Available Anaplastic large cell lymphoma (ALCL is a distinct type of CD30+ T/null-cell non-Hodgkin′s lymphoma that frequently involves nodal and extranodal sites. The presence of leukemic phase in ALCL is extremely rare and occurs exclusively with ALK1-positive ALCL. We describe two patients with ALK1-positive ALCL who developed a leukemic phase with rapid progression of the disease. Immunophenotypic pattern assessed on peripheral blood by flow cytometry revealed CD45, CD30, and CD25 positivity in both cases but NPM-ALK1 was expressed in only one case. Both patients developed leukemic phase as a terminal event of the disease and we share the immunophenotypic features of both cases.

  8. Membrane-less micro fuel cell based on two-phase flow

    Science.gov (United States)

    Hashemi, S. M. H.; Neuenschwander, M.; Hadikhani, P.; Modestino, M. A.; Psaltis, D.

    2017-04-01

    Most microfluidic fuel cells use highly soluble fuels and oxidants in streams of liquid electrolytes to overcome the mass transport limitations that result from the low solubility of gaseous reactants such as hydrogen and oxygen. In this work, we address these limitations by implementing controlled two-phase flows of these gases in a set of microchannels electrolytically connected through a narrow gap. Annular flows of the gases reshape the concentration boundary layer over the surface of electrodes and increase the mass-transport limited current density in the system. Our results show that the power density of a two-phase system with hydrogen and oxygen streams is an order of magnitude higher than that of single phase system consisting of liquid electrolytes saturated with the same reactants. The reactor design described here can be employed to boost the performance of MFFCs and put them in a more competitive position compared to membrane based fuel cells.

  9. Global analysis of phase locking in gene expression during cell cycle: the potential in network modeling

    Directory of Open Access Journals (Sweden)

    Hessner Martin J

    2010-12-01

    Full Text Available Abstract Background In nonlinear dynamic systems, synchrony through oscillation and frequency modulation is a general control strategy to coordinate multiple modules in response to external signals. Conversely, the synchrony information can be utilized to infer interaction. Increasing evidence suggests that frequency modulation is also common in transcription regulation. Results In this study, we investigate the potential of phase locking analysis, a technique to study the synchrony patterns, in the transcription network modeling of time course gene expression data. Using the yeast cell cycle data, we show that significant phase locking exists between transcription factors and their targets, between gene pairs with prior evidence of physical or genetic interactions, and among cell cycle genes. When compared with simple correlation we found that the phase locking metric can identify gene pairs that interact with each other more efficiently. In addition, it can automatically address issues of arbitrary time lags or different dynamic time scales in different genes, without the need for alignment. Interestingly, many of the phase locked gene pairs exhibit higher order than 1:1 locking, and significant phase lags with respect to each other. Based on these findings we propose a new phase locking metric for network reconstruction using time course gene expression data. We show that it is efficient at identifying network modules of focused biological themes that are important to cell cycle regulation. Conclusions Our result demonstrates the potential of phase locking analysis in transcription network modeling. It also suggests the importance of understanding the dynamics underlying the gene expression patterns.

  10. Phased array compaction cell for measurement of the transversely isotropic elastic properties of compacting sediments

    Energy Technology Data Exchange (ETDEWEB)

    Nihei, K.T.; Nakagawa, S.; Reverdy, F.; Meyer, L.R.; Duranti, L.; Ball, G.

    2010-12-15

    Sediments undergoing compaction typically exhibit transversely isotropic (TI) elastic properties. We present a new experimental apparatus, the phased array compaction cell, for measuring the TI elastic properties of clay-rich sediments during compaction. This apparatus uses matched sets of P- and S-wave ultrasonic transducers located along the sides of the sample and an ultrasonic P-wave phased array source, together with a miniature P-wave receiver on the top and bottom ends of the sample. The phased array measurements are used to form plane P-waves that provide estimates of the phase velocities over a range of angles. From these measurements, the five TI elastic constants can be recovered as the sediment is compacted, without the need for sample unloading, recoring, or reorienting. This paper provides descriptions of the apparatus, the data processing, and an application demonstrating recovery of the evolving TI properties of a compacting marine sediment sample.

  11. Integrated quantitative phase and birefringence microscopy for imaging malaria-infected red blood cells

    Science.gov (United States)

    Li, Chengshuai; Chen, Shichao; Klemba, Michael; Zhu, Yizheng

    2016-09-01

    A dual-modality birefringence/phase imaging system is presented. The system features a crystal retarder that provides polarization mixing and generates two interferometric carrier waves in a single signal spectrum. The retardation and orientation of sample birefringence can then be measured simultaneously based on spectral multiplexing interferometry. Further, with the addition of a Nomarski prism, the same setup can be used for quantitative differential interference contrast (DIC) imaging. Sample phase can then be obtained with two-dimensional integration. In addition, birefringence-induced phase error can be corrected using the birefringence data. This dual-modality approach is analyzed theoretically with Jones calculus and validated experimentally with malaria-infected red blood cells. The system generates not only corrected DIC and phase images, but a birefringence map that highlights the distribution of hemozoin crystals.

  12. Sequential processing of quantitative phase images for the study of cell behaviour in real-time digital holographic microscopy.

    Science.gov (United States)

    Zikmund, T; Kvasnica, L; Týč, M; Křížová, A; Colláková, J; Chmelík, R

    2014-11-01

    Transmitted light holographic microscopy is particularly used for quantitative phase imaging of transparent microscopic objects such as living cells. The study of the cell is based on extraction of the dynamic data on cell behaviour from the time-lapse sequence of the phase images. However, the phase images are affected by the phase aberrations that make the analysis particularly difficult. This is because the phase deformation is prone to change during long-term experiments. Here, we present a novel algorithm for sequential processing of living cells phase images in a time-lapse sequence. The algorithm compensates for the deformation of a phase image using weighted least-squares surface fitting. Moreover, it identifies and segments the individual cells in the phase image. All these procedures are performed automatically and applied immediately after obtaining every single phase image. This property of the algorithm is important for real-time cell quantitative phase imaging and instantaneous control of the course of the experiment by playback of the recorded sequence up to actual time. Such operator's intervention is a forerunner of process automation derived from image analysis. The efficiency of the propounded algorithm is demonstrated on images of rat fibrosarcoma cells using an off-axis holographic microscope.

  13. TGFβ lengthens the G1 phase of stem cells in aged mouse brain.

    Science.gov (United States)

    Daynac, Mathieu; Pineda, Jose R; Chicheportiche, Alexandra; Gauthier, Laurent R; Morizur, Lise; Boussin, François D; Mouthon, Marc-André

    2014-12-01

    Neurogenesis decreases during aging causing a progressive cognitive decline but it is still controversial whether proliferation defects in neurogenic niches result from a loss of neural stem cells or from an impairment of their progression through the cell cycle. Using an accurate fluorescence-activated cell sorting technique, we show that the pool of neural stem cells is maintained in the subventricular zone of middle-aged mice while they have a reduced proliferative potential eventually leading to the subsequent decrease of their progeny. In addition, we demonstrate that the G1 phase is lengthened during aging specifically in activated stem cells, but not in transit-amplifying cells, and directly impacts on neurogenesis. Finally, we report that inhibition of TGFβ signaling restores cell cycle progression defects in stem cells. Our data highlight the significance of cell cycle dysregulation in stem cells in the aged brain and provide an attractive foundation for the development of anti-TGFβ regenerative therapies based on stimulating endogenous neural stem cells.

  14. Morphology versus Vertical Phase Segregation in Solvent Annealed Small Molecule Bulk Heterojunction Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Alexander Kovalenko

    2015-01-01

    Full Text Available The deep study of solvent annealed small molecules bulk heterojunction organic solar cells based on DPP(TBFu2 : PC60BM blend is carried out. To reveal the reason of the solvent annealing advantage over the thermal one, capacitance-voltage measurements were applied. It was found that controlling the vertical phase segregation in the solar cells a high fullerene population in the vicinity of the cathode could be achieved. This results in increase of the shunt resistance of the cell, thus improving the light harvesting efficiency.

  15. Automated Detection of P. falciparum Using Machine Learning Algorithms with Quantitative Phase Images of Unstained Cells

    Science.gov (United States)

    Park, Han Sang; Rinehart, Matthew T.; Walzer, Katelyn A.; Chi, Jen-Tsan Ashley; Wax, Adam

    2016-01-01

    Malaria detection through microscopic examination of stained blood smears is a diagnostic challenge that heavily relies on the expertise of trained microscopists. This paper presents an automated analysis method for detection and staging of red blood cells infected by the malaria parasite Plasmodium falciparum at trophozoite or schizont stage. Unlike previous efforts in this area, this study uses quantitative phase images of unstained cells. Erythrocytes are automatically segmented using thresholds of optical phase and refocused to enable quantitative comparison of phase images. Refocused images are analyzed to extract 23 morphological descriptors based on the phase information. While all individual descriptors are highly statistically different between infected and uninfected cells, each descriptor does not enable separation of populations at a level satisfactory for clinical utility. To improve the diagnostic capacity, we applied various machine learning techniques, including linear discriminant classification (LDC), logistic regression (LR), and k-nearest neighbor classification (NNC), to formulate algorithms that combine all of the calculated physical parameters to distinguish cells more effectively. Results show that LDC provides the highest accuracy of up to 99.7% in detecting schizont stage infected cells compared to uninfected RBCs. NNC showed slightly better accuracy (99.5%) than either LDC (99.0%) or LR (99.1%) for discriminating late trophozoites from uninfected RBCs. However, for early trophozoites, LDC produced the best accuracy of 98%. Discrimination of infection stage was less accurate, producing high specificity (99.8%) but only 45.0%-66.8% sensitivity with early trophozoites most often mistaken for late trophozoite or schizont stage and late trophozoite and schizont stage most often confused for each other. Overall, this methodology points to a significant clinical potential of using quantitative phase imaging to detect and stage malaria infection

  16. Preparation of anatase/rutile mixed-phase titania nanoparticles for dye-sensitized solar cells.

    Science.gov (United States)

    Hwang, Yong-Kyung; Park, Sung Soo; Lim, Jun-Heok; Won, Yong Sun; Huh, Seong

    2013-03-01

    Acid-labile high surface mesoporous ZnO/Zn(OH)2 composite material is used as a novel hard template for the preparation of mesoporous amorphous TiO2. The template-free amorphous TiO2 material is then thermally crystallized at suitable temperature to control the relative ratio of anatase and rutile phases in a particle. Four different anatase/rutile (AR) mixed-phase TiO2 nanoparticles (AR-3, AR-15, AR-20, and AR-23 denoted for the samples of 3%, 15%, 20%, and 23% rutile phase, respectively) are prepared and characterized by powder X-ray diffraction (PXRD) and transmission electron microscopy (TEM). The coexistence of anatase and rutile phases in a TiO2 nanoparticle is visually confirmed by HRTEM analysis. These mixed-phase TiO2 nanoparticles are examined as candidates for photoelectrodes of dye-sensitized solar cells (DSSCs). The J-V curves and IPCE spectra for the DSSCs prepared from the mixed-phase TiO2 nanoparticles are obtained, and their photovoltaic properties are investigated. The photo-conversion efficiency (eta) indicates the highest value of 5.07% for AR-20. The synergistic effect of coexisting anatase and rutile phases with an optimal ratio in a TiO2 nanoparticle of AR-20 for an efficient interfacial transfer of photo-generated electrons is likely to lead to the highest efficiency among the AR-n samples.

  17. 心理行为因素对急进高原救灾官兵急性高原反应状况的影响%Study on acute mountain sickness and the psychological factors in the relief force during the initial phase of acute plateau exposure

    Institute of Scientific and Technical Information of China (English)

    高存友; 甘景梨; 赵兰民; 王丽杰

    2011-01-01

    目的 了解急进高原抗震救灾官兵的急性高原反应状况,并探讨其心理行为相关影响因素,为进一步研究预防措施提供参考依据.方法 整群随机抽取玉树抗震救灾某部162名官兵为研究对象,根据军标GJB1098-9急性高原反应的诊断和处理原则判断官兵的急性高原反应状况,采用一般情况调查表、症状自评量表(SCL-90)和生活事件量表(LES)调查相关因素.结果 救灾官兵急性高原反应的检出率为65.4%,其中轻度17.3%、中度31.5%、重度16.7%.临床表现中以气短、心慌、头昏、口唇发绀和头痛等症状最为多见,在救灾官兵中出现比率分别为83.6%、79.1%、73.1%、61.2%和58.2%.急性高原反应总计分与年龄、婚姻、心理创伤史,LES负性事件,SCL-90总分及其躯体化、强迫、抑郁、焦虑、敌对、恐怖、偏执、食欲睡眠等因子呈显著正相关(r值为0.188~0.619,P<0.01或0.05),与兴趣爱好、社会支持呈显著负相关(r值分别为-0.254,-0.285,P<0.01).多元逐步回归分析显示SCL-90的躯体化因子,兴趣爱好、婚姻、社会支持和年龄等因素进入回归方程.结论 大部分救灾官兵存在明显的急性高原反应,躯体化症状、兴趣爱好、婚姻、社会支持和年龄等因素对官兵的急性高原反应状况影响较大.%Objective To investigate the acute mountain sickness of servicemen during"4.14"Yushu earhquake relief work,and analyze the related factors of the sickness at the initial phase of acute plateau exposure.Methods 162 servicemen were sampled randomly and clusteringly from Yushu relief force during.the inidal phase of acute plateau exposure.According to the"Diagnosis and treatment principles of the acute mountain sickness",the prevalence of the acute mountain sickness was judged among the servicemen.The scales of general status invested score(GSIS),the self-rating symptom scale(SCL-90)and the life event scale(LES)were used to investigate the

  18. Balance of optical, structural, and electrical properties of textured liquid phase crystallized Si solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Preidel, V., E-mail: veit.preidel@helmholtz-berlin.de; Amkreutz, D.; Haschke, J.; Wollgarten, M.; Rech, B.; Becker, C. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Division Renewable Energy, Kekuléstr. 5, 12489 Berlin (Germany)

    2015-06-14

    Liquid phase crystallized Si thin-film solar cells on nanoimprint textured glass substrates exhibiting two characteristic, but distinct different surface structures are presented. The impact of the substrate texture on light absorption, the structural Si material properties, and the resulting solar cell performance is analyzed. A pronounced periodic substrate texture with a vertical feature size of about 1 μm enables excellent light scattering and light trapping. However, it also gives rise to an enhanced Si crystal defect formation deteriorating the solar cell performance. In contrast, a random pattern with a low surface roughness of 45 nm allows for the growth of Si thin films being comparable to Si layers on planar reference substrates. Amorphous Si/crystalline Si heterojunction solar cells fabricated on the low-roughness texture exhibit a maximum open circuit voltage of 616 mV and internal quantum efficiency peak values exceeding 90%, resulting in an efficiency potential of 13.2%. This demonstrates that high quality crystalline Si thin films can be realized on nanoimprint patterned glass substrates by liquid phase crystallization inspiring the implementation of tailor-made nanophotonic light harvesting concepts into future liquid phase crystallized Si thin film solar cells on glass.

  19. Sino-Japanese Teamwork Probes Environment Changes on Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ With the support of a CAS project on Holocene environmental changes and their influences on the ecosystem of the Tibetan Plateau, a research group headed by Prof. Zhu Liping from the CAS Institute of Tibetan Plateau Research and their Japanese collaborators carried out a field survey in Puma Yumco area on the Tibetan Plateau from September 8 to 20.

  20. Teachable, high-content analytics for live-cell, phase contrast movies.

    Science.gov (United States)

    Alworth, Samuel V; Watanabe, Hirotada; Lee, James S J

    2010-09-01

    CL-Quant is a new solution platform for broad, high-content, live-cell image analysis. Powered by novel machine learning technologies and teach-by-example interfaces, CL-Quant provides a platform for the rapid development and application of scalable, high-performance, and fully automated analytics for a broad range of live-cell microscopy imaging applications, including label-free phase contrast imaging. The authors used CL-Quant to teach off-the-shelf universal analytics, called standard recipes, for cell proliferation, wound healing, cell counting, and cell motility assays using phase contrast movies collected on the BioStation CT and BioStation IM platforms. Similar to application modules, standard recipes are intended to work robustly across a wide range of imaging conditions without requiring customization by the end user. The authors validated the performance of the standard recipes by comparing their performance with truth created manually, or by custom analytics optimized for each individual movie (and therefore yielding the best possible result for the image), and validated by independent review. The validation data show that the standard recipes' performance is comparable with the validated truth with low variation. The data validate that the CL-Quant standard recipes can provide robust results without customization for live-cell assays in broad cell types and laboratory settings.

  1. Desacetyluvaricin induces S phase arrest in SW480 colorectal cancer cells through superoxide overproduction.

    Science.gov (United States)

    Xue, Jun-Yi; Zhou, Guang-Xiong; Chen, Tianfeng; Gao, Si; Choi, Mei-Yuk; Wong, Yum-Shing

    2014-03-01

    Annonaceous acetogenins (ACGs) are a group of fatty acid-derivatives with potent anticancer effects. In the present study, we found desacetyluvaricin (Dau) exhibited notable in vitro antiproliferative effect on SW480 human colorectal carcinoma cells with IC50 value of 14 nM. The studies on the underlying mechanisms revealed that Dau inhibited the cancer cell growth through induction of S phase cell cycle arrest from 11.3% (control) to 33.2% (160 nM Dau), which was evidenced by the decreased protein expression of cyclin A Overproduction of superoxide, intracellular DNA damage, and inhibition of MEK/ERK signaling pathway, were also found involved in cells exposed to Dau. Moreover, pre-treatment of the cells with ascorbic acid significantly prevented the Dau-induced overproduction of superoxide, DNA damage and cell cycle arrest. Taken together, our results suggest that Dau induces S phase arrest in cancer cells by firstly superoxide overproduction and subsequently the involvement of various signaling pathways.

  2. The Hubble Flow of Plateau Inflation

    NARCIS (Netherlands)

    Coone, Dries; Roest, Diederik; Vennin, Vincent

    2015-01-01

    In the absence of CMB precision measurements, a Taylor expansion has often been invoked to parametrize the Hubble flow function during inflation. The standard "horizon flow" procedure implicitly relies on this assumption. However, the recent Planck results indicate a strong preference for plateau

  3. The Hubble Flow of Plateau Inflation

    NARCIS (Netherlands)

    Coone, Dries; Roest, Diederik; Vennin, Vincent

    2015-01-01

    In the absence of CMB precision measurements, a Taylor expansion has often been invoked to parametrize the Hubble flow function during inflation. The standard "horizon flow" procedure implicitly relies on this assumption. However, the recent Planck results indicate a strong preference for plateau in

  4. Ozone Minihole Found over Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Through a comprehensive analysis, researchers from the CAS Institute of Atmospheric Physics (IAP) discovered an ozone minihole, a large area with the lowest total ozone column (TOC, see figure), over the Qinghai-Tibet Plateau from Dec. 14 to 17, 2003.

  5. Construction of plateaued functions satisfying multiple criteria

    Institute of Scientific and Technical Information of China (English)

    Zhang Weiguo

    2005-01-01

    A class of plateaued functions has been got by using the Maiorana-McFarland construction. A variety of desirable criteria for functions with cryptographic application could be satisfied: balancedness, high nonlinearity, correlation immunity of reasonably high order, strict avalanche criterion, non-existence of non-zero linear structures, good global avalanche characteristics, etc.

  6. Planation Surfaces on the Tibet Plateau, China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A planation hypothesis is proposed to explain landform evolution of the Tibet Plateau. A denudation threshold (T), the maximum potential denudation rate for a certain type of rock, is introduced to explain the combined effects of lithology and tectonics on landform evolution. If the tectonic uplifting rate (U) is equal to or less than the threshold rate (U ≤ T), the tectonic uplifting and terrain denudation are in dynamic equilibrium, and landforms are in a steady state. The end product should be planation surfaces whether the original landforms are fiat plains or deeply dissected mountains. If U > T, uplift and denudation are not able to reach a dynamic equilibrium state. The plateau surface is mostly underlain by soft rocks, such as the Mesozoic epimetamorphic argillites and Tertiary sedimentary rocks, while the mountain ranges comprise hard rocks, such as granite, gneiss and limestone. In soft rock regions, hills are low with a relative relief of mostly less than 100m and the slopes are gentle at a gradient of <200. In contrast, hills can maintain steep slopes in hard rock regions. The Tibet Plateau has been under an equilibrium condition between tectonic uplifting and denudation except for the mountain ranges. The plateau might have reached the present altitudes before the Quaternary.

  7. Evodiamine induces caspase-dependent apoptosis and S phase arrest in human colon lovo cells.

    Science.gov (United States)

    Zhang, Chun; Fan, Xia; Xu, Xiang; Yang, Xue; Wang, Xi; Liang, Hua-Ping

    2010-09-01

    Evodiamine, one of the major bioactive components derived from Wu-Chu-Yu, a long-standing Chinese herb, was reported to possess anticancer activity. In this study, we investigated the in-vitro and in-vivo anticancer effects of evodiamine on human colon lovo cells and their potential mechanisms. The 3-(4, 5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide assay showed that the in-vitro proliferation of lovo cells was inhibited by evodiamine of various concentrations. Flow cytometry showed a time-dependent increase in the percentage of apoptotic cells and cells arrested in the S phase after treatment with 60 micromol/l evodiamine. Western blot indicated that evodiamine treatment decreased the expression of procaspase-8, procaspase-9, and procaspase-3 in lovo cells, accompanied by the activation of caspase-8, caspase-9, and caspase-3. However, the translocation of apoptosis-inducing factor and endonuclease G was not affected by evodiamine. Moreover, western blot assay also suggested that evodiamine-induced S phase arrest in lovo cells was associated with a marked decrease in the protein expression of cyclinA, cyclinA-dependent kinase 2, and cdc25c. In-vivo antineoplastic characteristics of evodiamine were examined in a human colon carcinoma lovo xenograft model and results showed that evodiamine increased the number of TUNEL-positive cells accompanied by the downregulated expression of procaspase-8, procaspase-9, and procaspase-3. In conclusion, these findings indicated that evodiamine could inhibit the in-vitro and in-vivo proliferation of human colon lovo cells by inducing caspase-dependent apoptosis and S phase arrest.

  8. Seeing tissue as a 'phase of matter': exploring statistical mechanics for the cell.

    Science.gov (United States)

    Pietak, Alexis; Waldman, Stephen D

    2008-04-01

    The field of tissue engineering aims to produce living, biological constructs which possess the appropriate spatial ordering of cells and their extra cellular matrix products. The complexity of a single cell and its interactions in a large collective have made development of useful models to assist in tissue culture difficult, and consequentially most tissue culture endeavors are limited to trial and error approaches. Some cell types display a natural tendency to spontaneously self-assemble into large domains of parallel-oriented cells. In this work, we show that these cell culture systems can be studied in the context of continuous disorder-order phase transformations. We suggest that collective ordering of the cells is controlled by the amount of noise in the walk of the individual cells (directional persistence) because undifferentiated mesenchymal stem cells display a seven-times higher directional persistence than mature fibroblasts and have a 24-times larger final-oriented domain size, an observation that corresponds with collective ordering in self-propelled particle systems. The study of cell culture systems using analogies derived from statistical mechanics yields simple, practical models offering insight into how a long-range order can be obtained in tissue-engineered constructs, providing a new paradigm for managing operations with large collectives of living cells.

  9. Ultrastructural Complexity of Nuclear Components During Early Apoptotic Phases in Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Christian Castelli

    2001-01-01

    Full Text Available Fractal morphometry was used to investigate the ultrastructural features of the plasma membrane, perinuclear membrane and nuclear chromatin in SK‐BR‐3 human breast cancer cells undergoing apoptosis. Cells were incubated with 1 μM calcimycin (A23187 for 24 h. Cells in the early stage of apoptosis had fractal dimension (FD values indicating that their plasma membranes were less rough (lower FD than those of control cells, while their perinuclear membranes were unaffected. Changes of the chromatin texture within the entire nucleus and in selected nuclear domains were more pronounced in treated cells. This confirms that the morphological reorganization imputable to a loss of structural complexity (reduced FD occurs in the early stage of apoptosis, is accompanied by the inhibition of distinct enzymatic events and precedes the onset of conventional cellular markers, which can only be detected during the active phases of the apoptotic process.

  10. Effect of synchronization of donor cells in early G1-phase using shake-off method on developmental potential of somatic cell nuclear transfer embryos in cattle.

    Science.gov (United States)

    Goto, Yuji; Hirayama, Muneyuki; Takeda, Kazuya; Tukamoto, Nobuyuki; Sakata, Osamu; Kaeriyama, Hiroshi; Geshi, Masaya

    2013-08-01

    In this study, we compared the developmental ability of somatic cell nuclear transfer (SCNT) embryos reconstructed with three bovine somatic cells that had been synchronized in G0-phase (G0-SCNT group) or early G1-phase (eG1-SCNT group). Furthermore, we investigated the production efficiency of cloned offspring for NT embryos derived from these donor cells. The G0-phase and eG1-phase cells were synchronized, respectively, using serum starvation and antimitotic reagent treatment combined with shaking of the plate containing the cells (shake-off method). The fusion rate in the G0-SCNT groups (64.2 ± 1.8%) was significantly higher than that of eG1-SCNT groups (39.2 ± 1.9%) (P cells in eG1-phase using the shake-off method improved the overall production efficiency of the clone offspring per transferred embryo.

  11. S phase progression in human cells is dictated by the genetic continuity of DNA foci.

    Directory of Open Access Journals (Sweden)

    Apolinar Maya-Mendoza

    2010-04-01

    Full Text Available DNA synthesis must be performed with extreme precision to maintain genomic integrity. In mammalian cells, different genomic regions are replicated at defined times, perhaps to preserve epigenetic information and cell differentiation status. However, the molecular principles that define this S phase program are unknown. By analyzing replication foci within discrete chromosome territories during interphase, we show that foci which are active during consecutive intervals of S phase are maintained as spatially adjacent neighbors throughout the cell cycle. Using extended DNA fibers, we demonstrate that this spatial continuity of replication foci correlates with the genetic continuity of adjacent replicon clusters along chromosomes. Finally, we used bioinformatic tools to compare the structure of DNA foci with DNA domains that are seen to replicate during discrete time intervals of S phase using genome-wide strategies. Data presented show that a major mechanism of S phase progression involves the sequential synthesis of regions of the genome because of their genetic continuity along the chromosomal fiber.

  12. The intracrustal structure beneath the Owyhee Plateau, Oregon, from receiver function analysis

    Science.gov (United States)

    Hou, T.; Chen, C.; James, D. E.; Fouch, M. J.

    2013-12-01

    The Owyhee Plateau straddles southeastern Oregon, southwestern Idaho, and northern Nevada, and is an isolated block of older, and less modified, continental lithosphere relative to bordering geologic terranes. Previous seismic studies have characterized the Owyhee Plateau as having thickened crust with low Poisson's ratio and high intracrustal S-wave velocities, and distinct, albeit thin, mantle lithosphere. Significant tectonomagmatic activity, including extension in the northern Great Basin, and intraplate volcanism is present on the margins of the Plateau, but very little volcanism takes place within the Plateau itself. The volcanism is expressed as two prominent age-progressive volcanic tracks, the Snake River Plains-Yellowstone and the High Lava Plains, both of which appear to have originated from near the Owyhee Plateau at approximately 12 Ma. Recent ambient noise tomography and scattered-wave imaging reveal the presence of irregular high velocity layering in the Owyhee mid-crust, but the extent and properties of this feature, and its role in the tectonic evolution of the Owyhee Plateau, remain elusive. In this study, we perform detailed single station Ps receiver function analysis to better constrain the discontinuity structures within the Owyhee crust. We use teleseismic waveform data recorded at 28 High Lava Plains seismic array and 12 USArray Transportable Array broadband stations from 2006 to 2009. Preliminary results show coherent signals of converted phase at ~20 km depth, indicating the presence of a positive velocity discontinuity, which may mark the upper bound of the high velocity layer imaged in previous studies. We consider and examine possible effects of seismic anisotropy on our results and are also conducting synthetic experiments to further constrain the properties of this feature.

  13. Phase III Advanced Anodes and Cathodes Utilized in Energy Efficient Aluminum Production Cells

    Energy Technology Data Exchange (ETDEWEB)

    R.A. Christini; R.K. Dawless; S.P. Ray; D.A. Weirauch, Jr.

    2001-11-05

    During Phase I of the present program, Alcoa developed a commercial cell concept that has been estimated to save 30% of the energy required for aluminum smelting. Phase ii involved the construction of a pilot facility and operation of two pilots. Phase iii of the Advanced Anodes and Cathodes Program was aimed at bench experiments to permit the resolution of certain questions to be followed by three pilot cells. All of the milestones related to materials, in particular metal purity, were attained with distinct improvements over work in previous phases of the program. NiO additions to the ceramic phase and Ag additions to the Cu metal phase of the cermet improved corrosion resistance sufficiently that the bench scale pencil anodes met the purity milestones. Some excellent metal purity results have been obtained with anodes of the following composition: Further improvements in anode material composition appear to be dependent on a better understanding of oxide solubilities in molten cryolite. For that reason, work was commissioned with an outside consultant to model the MeO - cryolite systems. That work has led to a better understanding of which oxides can be used to substitute into the NiO-Fe2O3 ceramic phase to stabilize the ferrites and reduce their solubility in molten cryolite. An extensive number of vertical plate bench electrolysis cells were run to try to find conditions where high current efficiencies could be attained. TiB2-G plates were very inconsistent and led to poor wetting and drainage. Pure TiB2 did produce good current efficiencies at small overlaps (shadowing) between the anodes and cathodes. This bench work with vertical plate anodes and cathodes reinforced the importance of good cathode wetting to attain high current efficiencies. Because of those conclusions, new wetting work was commissioned and became a major component of the research during the third year of Phase III. While significant progress was made in several areas, much work needs to be

  14. Submicron-scale manipulation of phase separation in organic solar cells

    Science.gov (United States)

    Chen, Fang-Chung; Lin, Yi-Kai; Ko, Chu-Jung

    2008-01-01

    This paper describes a method for controlling the submicron-scale phase separation of poly(3-hexylthiophene) and (6,6)-phenyl-C61-butyric acid methyl ester in organic solar cells. Using microcontact printing of self-assembled monolayers on the device buffer layer to divide the surface into two regimes having different surface energies, an interdigitated structure aligned vertical to the substrate surface is achieved after spontaneous surface-directed phase separation. The power conversion efficiency increases upon decreasing the grating spacing, reaching 2.47%. The hole mobility increased as a consequence of improved polymer chain ordering, resulting in higher device efficiency, while smaller pattern sizes were used.

  15. Phase II enzyme induction by a carotenoid, lutein, in a PC12D neuronal cell line

    Energy Technology Data Exchange (ETDEWEB)

    Miyake, Seiji [Laboratory of Retinal Cell Biology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Wakasa Seikatsu Co., Ltd., 134 Chudoujiminami-cho, Shimogyo-ku, Kyoto 600-8813 (Japan); Kobayashi, Saori [Wakasa Seikatsu Co., Ltd., 134 Chudoujiminami-cho, Shimogyo-ku, Kyoto 600-8813 (Japan); Tsubota, Kazuo [Laboratory of Retinal Cell Biology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Ozawa, Yoko, E-mail: ozawa@a5.keio.jp [Laboratory of Retinal Cell Biology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan)

    2014-04-04

    Highlights: • Lutein reduced ROS levels in a PC12D neuronal cell line. • Lutein induced mRNAs of phase II antioxidative enzymes in PC12D neuronal cells. • Lutein increased protein levels of HO-1, SOD2, and NQO-1 in PC12D neuronal cells. • Lutein had no effect on intranuclear Nrf2 levels in PC12D neuronal cells. • Lutein did not activate potential upstream Nrf2 nuclear translocation pathways. - Abstract: The mechanism by which lutein, a carotenoid, acts as an antioxidant in retinal cells is still not fully understood. Here, lutein treatment of a neuronal cell line (PC12D) immediately resulted in reduced intracellular ROS levels, implying that it has a direct role in ROS scavenging. Significantly, lutein treatment also induced phase II antioxidative enzyme expression, probably via a nuclear factor-like 2 (Nrf2) independent pathway. This latter mechanism could explain why lutein acts diversely to protect against oxidative/cytotoxic stress, and why it is physiologically involved in the human neural tissue, such as the retina.

  16. Mefloquine inhibits chondrocytic proliferation by arresting cell cycle in G2/M phase.

    Science.gov (United States)

    Li, Qiong; Chen, Zeng-Gan; Xia, Qing; Lin, Jian-Ping; Yan, Zuo-Qin; Yao, Zheng-Jun; Dong, Jian

    2015-01-01

    Mefloquine (MQ), an analog of chloroquine, exhibits a promising cytotoxic activity against carcinoma cell lines and for the treatment of glioblastoma patients. The present study demonstrates the effect of mefloquine on proliferation and cell cycle in chondrocytes. MTT assay and propidium iodide staining were used for the analysis of proliferation and cell cycle distribution, respectively. Western blot analysis was used to examine the expression levels of cyclin B1/cdc2, cdc25c, p21WAF1/CIP1 and p53. The results revealed that mefloquine inhibited the proliferation of chondrocytes and caused cell cycle arrests in the G2/M phase. The proliferation of chondrocytes was reduced to 27% at 40 μM concentration of mefloquine after 48 h. The population of chondrocytes in G2/M phase was found to be 15.7 and 48.4%, respectively at 10 and 40 μM concentration of mefloquine at 48 h following treatment. The expression of the cell cycle regulatory proteins including, cyclin B1/cdc2 and cdc25c was inhibited. On the other hand, mefloquine treatment promoted the expression of p21WAF1/CIP1 and p53 at 40 μM concentration after 48 h. Therefore, mefloquine inhibits proliferation and induces cell cycle arrest in chondrocytes.

  17. The evolution of pretransfusion testing: from agglutination to solid-phase red cell adherence tests.

    Science.gov (United States)

    Plapp, F V; Sinor, L T; Rachel, J M

    1989-01-01

    Hospital transfusion services and blood centers still use manual hemagglutination tests for most of their serological procedures. Automation of hemagglutination reactions has proven to be difficult, primarily because hemagglutination lacks an objective endpoint which can be easily interpreted by inexpensive instruments. Alternatively, solid-phase red cell adherence assays for ABO cell and serum grouping, Rh typing, red cell and platelet antibody screening, red cell and platelet crossmatching, IgA deficiency screening, hepatitis B surface antigen, and HIV antibody screening have been developed. The performance of these assays compares favorably with current hemagglutination and enzyme immunoassay methods. All of these tests share a common objective endpoint of adherence or nonadherence of indicator red cells. This uniformity allows easy interpretation of results visually, spectrophotometrically, or by image analysis. The latter technique has the potential to revolutionize the reading and interpretation of all agglutination tests. Solid-phase red cell adherence tests in microplates are ideal for batch processing large numbers of specimens. However, adherence tests are not restricted to this format. Therefore, blood grouping dipsticks have been produced, which permit testing of individual blood samples even outside of the laboratory.

  18. Extracting the temperature distribution on a phase-change memory cell during crystallization

    Science.gov (United States)

    Bakan, Gokhan; Gerislioglu, Burak; Dirisaglik, Faruk; Jurado, Zoila; Sullivan, Lindsay; Dana, Aykutlu; Lam, Chung; Gokirmak, Ali; Silva, Helena

    2016-10-01

    Phase-change memory (PCM) devices are enabled by amorphization- and crystallization-induced changes in the devices' electrical resistances. Amorphization is achieved by melting and quenching the active volume using short duration electrical pulses (˜ns). The crystallization (set) pulse duration, however, is much longer and depends on the cell temperature reached during the pulse. Hence, the temperature-dependent crystallization process of the phase-change materials at the device level has to be well characterized to achieve fast PCM operations. A main challenge is determining the cell temperature during crystallization. Here, we report extraction of the temperature distribution on a lateral PCM cell during a set pulse using measured voltage-current characteristics and thermal modelling. The effect of the thermal properties of materials on the extracted cell temperature is also studied, and a better cell design is proposed for more accurate temperature extraction. The demonstrated study provides promising results for characterization of the temperature-dependent crystallization process within a cell.

  19. Video-rate processing in tomographic phase microscopy of biological cells using CUDA.

    Science.gov (United States)

    Dardikman, Gili; Habaza, Mor; Waller, Laura; Shaked, Natan T

    2016-05-30

    We suggest a new implementation for rapid reconstruction of three-dimensional (3-D) refractive index (RI) maps of biological cells acquired by tomographic phase microscopy (TPM). The TPM computational reconstruction process is extremely time consuming, making the analysis of large data sets unreasonably slow and the real-time 3-D visualization of the results impossible. Our implementation uses new phase extraction, phase unwrapping and Fourier slice algorithms, suitable for efficient CPU or GPU implementations. The experimental setup includes an external off-axis interferometric module connected to an inverted microscope illuminated coherently. We used single cell rotation by micro-manipulation to obtain interferometric projections from 73 viewing angles over a 180° angular range. Our parallel algorithms were implemented using Nvidia's CUDA C platform, running on Nvidia's Tesla K20c GPU. This implementation yields, for the first time to our knowledge, a 3-D reconstruction rate higher than video rate of 25 frames per second for 256 × 256-pixel interferograms with 73 different projection angles (64 × 64 × 64 output). This allows us to calculate additional cellular parameters, while still processing faster than video rate. This technique is expected to find uses for real-time 3-D cell visualization and processing, while yielding fast feedback for medical diagnosis and cell sorting.

  20. Isolation of a cdc28 mutation that abrogates the dependence of S phase on completion of M phase of the budding yeast cell cycle

    Indian Academy of Sciences (India)

    Santanu Kumar Ghosh; Pratima Sinha

    2000-01-01

    We have isolated a mutation in the budding yeast Saccharomyces cerevisisae CDC28 gene that allows cdc13 cells, carrying damaged DNA, to continue with the cell division cycle. While cdc13 mutant cells are arrested as large-budded cells at the nonpermissive temperature 37°C, the cdc13 cdc28 double mutant culture showed cells with one or more buds, most of which showed apical growth. The additional buds emerged without the intervening steps of nuclear division and cell separation. We suggest that the cdc28 mutation abrogates a checkpoint function and allows cells with damaged or incompletely replicated DNA an entry to another round of cell cycle and bypasses the mitotic phase of the cell cycle.

  1. Soil erosion and management on the Loess Plateau

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The Loess Plateau is well known to the world for its intense soil erosion. The root cause for river sedimentation of Yellow River (Huanghe) and its resultant "hanging river" in certain section is soil and water loss on the Loess Plateau. The Loess Plateau has a long cultivation history, hence population growth, vegetation degeneration and plugging constitute the chief reason for serious soil and water loss on Loess Plateau. This paper analyses several successful cases and failures in soil conservation, presents practical soil conservation technique and related benefit analysis, and discusses some effective methods adopted in China in soil erosion control, research directions and future perspectives on Loess Plateau.

  2. Structure and multiphased evolution of the Demerara plateau (offshore Suriname, French Guiana)

    Science.gov (United States)

    Mercier de Lépinay, Marion; Basile, Christophe; Loncke, Lies; Maillard, Agnès; Grall, Céline; Roest, Walter R.; de Clarens, Philippe

    2014-05-01

    Offshore Suriname and French Guiana, the Demerara plateau is a continental indentation at the intersection of two oceanic domains : the Jurassic Central Atlantic and the Early Cretaceous Equatorial Atlantic. Its three borders are passive margins. The northern one is a transform margin, the two others are rifted margins, thinned during Trias/Jurassic (westward), and a second time during Early Cretaceous (eastward). The main stratigraphic feature of the Demerara plateau is the major upper Albian angular erosive unconformity, synchronous to the Equatorial Atlantic break-up. We here focus on the sedimentary records observed below the upper Albian discordance, where seismic data show more than 13 km of layered units. The aim of this study is to give new insights about the evolution of the Demerara plateau during Mesozoic times, in order to constrain vertical displacements especially in relation with the transform margin. We use mostly structural interpretation of industrial and academic seismic lines (GUYAPLAC, 2003 and IGUANES, 2013), calibrated by industrial wells down to Berriasian times. It allows us to propose structural maps and regional interpretative cross-sections of the plateau and its three borders. On seismic lines, undated prominent seismic units are characterized by important thickness variations, and weak continuity of intern reflectors. They thicken westward (toward the Central Atlantic ocean). One possible interpretation is to relate these units to trias/jurassic syn-rift sediments deposition associated to a continentward dipping fault. But the complex is formed by a repetition of several layer fans. Hence one alternative interpretation would be that these units were seaward dipping reflectors stacked during Trias/Jurassic rifting, suggesting that the role of magmatism should have been predominant during the first phase of the plateau formation. All the sediments of the plateau, including Aptian sediments, are deformed with numerous structures (strike

  3. A novel single virus infection system reveals that influenza virus preferentially infects cells in g1 phase.

    Directory of Open Access Journals (Sweden)

    Ryuta Ueda

    Full Text Available BACKGROUND: Influenza virus attaches to sialic acid residues on the surface of host cells via the hemagglutinin (HA, a glycoprotein expressed on the viral envelope, and enters into the cytoplasm by receptor-mediated endocytosis. The viral genome is released and transported in to the nucleus, where transcription and replication take place. However, cellular factors affecting the influenza virus infection such as the cell cycle remain uncharacterized. METHODS/RESULTS: To resolve the influence of cell cycle on influenza virus infection, we performed a single-virus infection analysis using optical tweezers. Using this newly developed single-virus infection system, the fluorescence-labeled influenza virus was trapped on a microchip using a laser (1064 nm at 0.6 W, transported, and released onto individual H292 human lung epithelial cells. Interestingly, the influenza virus attached selectively to cells in the G1-phase. To clarify the molecular differences between cells in G1- and S/G2/M-phase, we performed several physical and chemical assays. Results indicated that: 1 the membranes of cells in G1-phase contained greater amounts of sialic acids (glycoproteins than the membranes of cells in S/G2/M-phase; 2 the membrane stiffness of cells in S/G2/M-phase is more rigid than those in G1-phase by measurement using optical tweezers; and 3 S/G2/M-phase cells contained higher content of Gb3, Gb4 and GlcCer than G1-phase cells by an assay for lipid composition. CONCLUSIONS: A novel single-virus infection system was developed to characterize the difference in influenza virus susceptibility between G1- and S/G2/M-phase cells. Differences in virus binding specificity were associated with alterations in the lipid composition, sialic acid content, and membrane stiffness. This single-virus infection system will be useful for studying the infection mechanisms of other viruses.

  4. Cell size at S phase initiation: an emergent property of the G1/S network.

    Directory of Open Access Journals (Sweden)

    Matteo Barberis

    2007-04-01

    Full Text Available The eukaryotic cell cycle is the repeated sequence of events that enable the division of a cell into two daughter cells. It is divided into four phases: G1, S, G2, and M. Passage through the cell cycle is strictly regulated by a molecular interaction network, which involves the periodic synthesis and destruction of cyclins that bind and activate cyclin-dependent kinases that are present in nonlimiting amounts. Cyclin-dependent kinase inhibitors contribute to cell cycle control. Budding yeast is an established model organism for cell cycle studies, and several mathematical models have been proposed for its cell cycle. An area of major relevance in cell cycle control is the G1 to S transition. In any given growth condition, it is characterized by the requirement of a specific, critical cell size, PS, to enter S phase. The molecular basis of this control is still under discussion. The authors report a mathematical model of the G1 to S network that newly takes into account nucleo/cytoplasmic localization, the role of the cyclin-dependent kinase Sic1 in facilitating nuclear import of its cognate Cdk1-Clb5, Whi5 control, and carbon source regulation of Sic1 and Sic1-containing complexes. The model was implemented by a set of ordinary differential equations that describe the temporal change of the concentration of the involved proteins and protein complexes. The model was tested by simulation in several genetic and nutritional setups and was found to be neatly consistent with experimental data. To estimate PS, the authors developed a hybrid model including a probabilistic component for firing of DNA replication origins. Sensitivity analysis of PS provides a novel relevant conclusion: PS is an emergent property of the G1 to S network that strongly depends on growth rate.

  5. 自我职涯管理与职涯高原的关系%The Relationship between Individual Career Management and Career Plateau of Employees

    Institute of Scientific and Technical Information of China (English)

    曾垂凯

    2012-01-01

    组织结构扁平化导致职涯高原员工逐渐增多,给个体和组织造成了消极影响。本文通过对338名企业员工的问卷调查探讨自我职涯管理与职涯高原的关系。研究结果显示:自我职涯管理中的职业探索与层级高原、内容高原及中心化高原正相关;目标确定与层级高原、关注学习与内容高原、注重关系与中心化高原及内容高原负相关;自我展示虽在简单相关分析中与内容高原及中心化高原负相关,但在回归分析中则相关不显著。%With the flatting development of the organization structure and gradually reduced management levels,promotion becomes more difficult than ever.More and more employees,especially management personnel,are getting into trouble with stagnation of career development.Then,career plateau phenomenon appears.According to the idea of Zeng Chuikai,career plateau is such a phenomena that in a certain phase of individuals career development,the long stay in a position makes the career flow(including vertical flow,horizontal flow,and central flow) difficult to realize,and causes his or her career development stagnation.Career plateau includes three aspects-hierarchal plateau(few possibility to promote in present organization),content plateau(few opportunity to learn new skills), and inclusive plateau(few possibility towards responsibility center).Since career plateau brings lots of adverse influences to both individuals and organizations,its relationship with individual career management now receives more and more attention in the world. To explore the relationship between individual career management and career plateau,in this research we made a questionnaire survey on employees of firms on the Chinese mainland.Out of a samples of 396 employees,338 questionnaires were valid.The questionnaires comprised three parts.Part one included items about the demographic characteristics of the subjects.Part two adopted the Individual Career

  6. An Open-Label, Multicenter, Phase 1/2 Study of E7438 (EZH2 Histone Methyl Transferase [HMT] Inhibitor) as a Single Agent in Subjects With Advanced Solid Tumors or With B-cell Lymphomas

    Science.gov (United States)

    2016-09-01

    B-cell Lymphomas (Phase 1); Advanced Solid Tumors (Phase 1); Diffuse Large B-cell Lymphoma (Phase 2); Follicular Lymphoma (Phase 2); Transformed Follicular Lymphoma; Primary Mediastinal Large B-Cell Lymphoma

  7. Piperine causes G1 phase cell cycle arrest and apoptosis in melanoma cells through checkpoint kinase-1 activation.

    Directory of Open Access Journals (Sweden)

    Neel M Fofaria

    Full Text Available In this study, we determined the cytotoxic effects of piperine, a major constituent of black and long pepper in melanoma cells. Piperine treatment inhibited the growth of SK MEL 28 and B16 F0 cells in a dose and time-dependent manner. The growth inhibitory effects of piperine were mediated by cell cycle arrest of both the cell lines in G1 phase. The G1 arrest by piperine correlated with the down-regulation of cyclin D1 and induction of p21. Furthermore, this growth arrest by piperine treatment was associated with DNA damage as indicated by phosphorylation of H2AX at Ser139, activation of ataxia telangiectasia and rad3-related protein (ATR and checkpoint kinase 1 (Chk1. Pretreatment with AZD 7762, a Chk1 inhibitor not only abrogated the activation of Chk1 but also piperine mediated G1 arrest. Similarly, transfection of cells with Chk1 siRNA completely protected the cells from G1 arrest induced by piperine. Piperine treatment caused down-regulation of E2F1 and phosphorylation of retinoblastoma protein (Rb. Apoptosis induced by piperine was associated with down-regulation of XIAP, Bid (full length and cleavage of Caspase-3 and PARP. Furthermore, our results showed that piperine treatment generated ROS in melanoma cells. Blocking ROS by tiron protected the cells from piperine mediated cell cycle arrest and apoptosis. These results suggest that piperine mediated ROS played a critical role in inducing DNA damage and activation of Chk1 leading to G1 cell cycle arrest and apoptosis.

  8. Hydrogeology of the Markagunt Plateau, Southwestern Utah

    Science.gov (United States)

    Spangler, Lawrence E.

    2010-01-01

    The Markagunt Plateau, in southwestern Utah, lies at an altitude of about 9,500 feet and is capped primarily by Quaternary-age basalt that overlies Eocene-age freshwater limestone of the Claron Formation. Over large parts of the Markagunt Plateau, dissolution of the Claron limestone and subsequent collapse of the overlying basalt have produced a terrain characterized by sinkholes as much as 1,000 feet across and 100 feet deep. Numerous large springs discharge from the basalt and underlying limestone on the plateau, including Mammoth Spring, one of the largest springs in Utah, with a discharge that can exceed 300 cubic feet per second. Discharge from Mammoth Spring is from the Claron Formation; however, recharge to the spring largely takes place by both focused and diffuse infiltration through the basalt that caps the limestone. Results of dye tracing to Mammoth Spring indicate that recharge originates largely southwest of the spring outside of the Mammoth Creek watershed, as well as from losing reaches along Mammoth Creek. Maximum groundwater travel time to the spring from dye-tracer tests during the snowmelt runoff period was about 1 week. Specific conductance and water temperature data from the spring show an inverse relation to discharge during snowmelt runoff and rainfall events, also indicating short groundwater residence times. Results of major-ion analyses for samples collected from Mammoth and other springs on the plateau indicate calcium-bicarbonate type water containing low (less than 200 mg/L) dissolved-solids concentrations. Investigations in the Navajo Lake area along the southern margin of the plateau have shown that water losing to sinkholes bifurcates and discharges to both Cascade and Duck Creek Springs, which subsequently flow into the Virgin and Sevier River basins, respectively. Groundwater travel times to these springs, on the basis of dye tracing, were about 8.5 and 53 hours, respectively. Similarly, groundwater travel time from Duck Creek

  9. Snow surface microbiome on the High Antarctic Plateau (DOME C.

    Directory of Open Access Journals (Sweden)

    Luigi Michaud

    Full Text Available The cryosphere is an integral part of the global climate system and one of the major habitable ecosystems of Earth's biosphere. These permanently frozen environments harbor diverse, viable and metabolically active microbial populations that represent almost all the major phylogenetic groups. In this study, we investigated the microbial diversity in the surface snow surrounding the Concordia Research Station on the High Antarctic Plateau through a polyphasic approach, including direct prokaryotic quantification by flow cytometry and catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH, and phylogenetic identification by 16S RNA gene clone library sequencing and 454 16S amplicon pyrosequencing. Although the microbial abundance was low (<10(3 cells/ml of snowmelt, concordant results were obtained with the different techniques. The microbial community was mainly composed of members of the Alpha-proteobacteria class (e.g. Kiloniellaceae and Rhodobacteraceae, which is one of the most well-represented bacterial groups in marine habitats, Bacteroidetes (e.g. Cryomorphaceae and Flavobacteriaceae and Cyanobacteria. Based on our results, polar microorganisms could not only be considered as deposited airborne particles, but as an active component of the snowpack ecology of the High Antarctic Plateau.

  10. Live cell refractometry using Hilbert phase microscopy and confocal reflectance microscopy.

    Science.gov (United States)

    Lue, Niyom; Choi, Wonshik; Popescu, Gabriel; Yaqoob, Zahid; Badizadegan, Kamran; Dasari, Ramachandra R; Feld, Michael S

    2009-11-26

    Quantitative chemical analysis has served as a useful tool for understanding cellular metabolisms in biology. Among many physical properties used in chemical analysis, refractive index in particular has provided molecular concentration that is an important indicator for biological activities. In this report, we present a method of extracting full-field refractive index maps of live cells in their native states. We first record full-field optical thickness maps of living cells by Hilbert phase microscopy and then acquire physical thickness maps of the same cells using a custom-built confocal reflectance microscope. Full-field and axially averaged refractive index maps are acquired from the ratio of optical thickness to physical thickness. The accuracy of the axially averaged index measurement is 0.002. This approach can provide novel biological assays of label-free living cells in situ.

  11. Live Cell Refractometry Using Hilbert Phase Microscopy and Confocal Reflectance Microscopy†

    Science.gov (United States)

    Lue, Niyom; Choi, Wonshik; Popescu, Gabriel; Yaqoob, Zahid; Badizadegan, Kamran; Dasari, Ramachandra R.; Feld, Michael S.

    2010-01-01

    Quantitative chemical analysis has served as a useful tool for understanding cellular metabolisms in biology. Among many physical properties used in chemical analysis, refractive index in particular has provided molecular concentration that is an important indicator for biological activities. In this report, we present a method of extracting full-field refractive index maps of live cells in their native states. We first record full-field optical thickness maps of living cells by Hilbert phase microscopy and then acquire physical thickness maps of the same cells using a custom-built confocal reflectance microscope. Full-field and axially averaged refractive index maps are acquired from the ratio of optical thickness to physical thickness. The accuracy of the axially averaged index measurement is 0.002. This approach can provide novel biological assays of label-free living cells in situ. PMID:19803506

  12. Parallel optical sorting of biological cells using the generalized phase contrast method

    DEFF Research Database (Denmark)

    Rindorf, Lars; Bu, Minqiang; Glückstad, Jesper

    2014-01-01

    of biological cells in microfluidic systems exclusively using light. We demonstrate an optical cell sorter that uses simultaneous manipulation by multiple laser beams using the Generalized Phase Contrast method (GPC). The basic principle in an optical sorter is that the radiation force of the optical beam can...... push the biological cell from one microfluidic sheath flow to another. By incorporating a spatial light modulator the manipulation can be made parallel with multiple laser beams. We claim advantages over the serial optical sorters with only a single laser beam that has been demonstrated by others.......Optical forces are used to fixate biological cells with optical tweezers where numerous biological parameters and phenomena can be studied. Optical beams carry a small momentum which generates a weak optical force, but on a cellular level this force is strong enough to allow for manipulation...

  13. Improving the performance of polymer solar cells by adjusting the crystallinity and nanoscale phase separation

    Institute of Scientific and Technical Information of China (English)

    Chen Wei-Bing; Xu Zong-Xiang; Li Kai; Chui Stephen Sin-Yin; Roy V.A.L.; Lai Pui-To; Che Chi-Ming

    2012-01-01

    In this paper,we report a high-performance P3HT/PCBM bulk-heterojunction solar cell with a power conversion efficiency of 4.85% fabricated by adjusting the polymer crystallinity and nanoscale phase separation using an ultrasonic irradiation mixing approach for the polymer.The grazing incidence X-ray diffraction,UV/Vis spectroscopic,and atomic force microscopic measurement results for the P3HT/PCBM blend films reveal that the P3HT/PCBM film fabricated by ultrasonic irradiation mixing of the P3HT and PCBM solutions for 10 min has a higher degree of cryetallinity,a higher absorption efficiency,and better phase separation,which together account for the higher charge transport properties and photovoltaic cell performance.

  14. Haploidentical Natural Killer Cells Infused before Allogeneic Stem Cell Transplantation for Myeloid Malignancies: A Phase I Trial.

    Science.gov (United States)

    Lee, Dean A; Denman, Cecele J; Rondon, Gabriela; Woodworth, Glenda; Chen, Julianne; Fisher, Tobi; Kaur, Indreshpal; Fernandez-Vina, Marcelo; Cao, Kai; Ciurea, Stefan; Shpall, Elizabeth J; Champlin, Richard E

    2016-07-01

    Allogeneic stem cell transplantation is an effective treatment for high-risk myeloid malignancies, but relapse remains the major post-transplantation cause of treatment failure. Alloreactive natural killer (NK) cells mediate a potent antileukemic effect and may also enhance engraftment and reduce graft-versus-host disease (GVHD). Haploidentical transplantations provide a setting in which NK cell alloreactivity can be manipulated, but they are associated with high rates of GVHD. We performed a phase I study infusing escalating doses of NK cells from an HLA haploidentical-related donor-selected for alloreactivity when possible-as a component of the preparative regimen for allotransplantation from a separate HLA-identical donor. The goal of infusing third-party alloreactive NK cells was to augment the antileukemic effect of the transplantation without worsening GVHD and, thus, improve the overall outcome of hematopoietic transplantation. Twenty-one patients with high-risk acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), or chronic myelogenous leukemia refractory or beyond first remission received a preparative regimen with busulfan and fludarabine followed by infusion of apheresis-derived, antibody-selected, and IL-2-activated NK cells. Doses were initially based on total nucleated cell (TNC) content and later based on CD56(+) cells to reduce variability. CD56(+) content ranged from .02 to 8.32 × 10(6)/kg. IL-2, .5 × 10(6) units/m(2) subcutaneously was administered daily for 5 days in the final cohort (n = 10). CD3(+) cells in the NK cell product were required to be transplantation-related causes, and 11 patients died of relapse. Despite the small sample size, survival was highly associated with CD56(+) cells delivered (P = .022) and development of ≥ grade 3 GVHD (P = .006). There were nonsignificant trends toward higher survival rates in those receiving NK cells from KIR ligand-mismatched donors and KIR-B haplotype donors. There was no

  15. Phase and microstructural stability of electrolyte matrix materials for molten carbonate fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Choi, H.J.; Lee, J.J. [School of Advanced Materials Science and Engineering, College of Engineering, Yonsei University, Seoul 120-749 (Korea); Lim, H.C. [KEPRI, Korea Electric Power Research Institute, Yuseong-gu, Daejeon 103-16, 305-380 (Korea); Hyun, S.H.

    2010-08-15

    LiAlO{sub 2} powder is used as a material for molten-carbonate fuel cell (MCFC) matrices. The physical and chemical stabilities of LiAlO{sub 2} powder during MCFC operation determine the performance and lifetimes of the cells. Change to the phase and particle size in the allotropic phase of LiAlO{sub 2} was examined with long-term stability tests on pure {alpha}-LiAlO{sub 2} matrix, Al-reinforced {alpha}-LiAlO{sub 2} matrix, Al-reinforced {gamma}-LiAlO{sub 2} matrix, aqueous {gamma}-LiAlO{sub 2} matrix and an {alpha}-/{beta}-LiAlO{sub 2} mixture powder in molten carbonate at 650 C in air. In the {gamma}-LiAlO{sub 2} and {alpha}-/{beta}-LiAlO{sub 2} mixture, the particle growth was continuous from the early stages of heat-treatment to 20,000 h. Crystalline phase transformation ({gamma}-LiAlO{sub 2} and {beta}-LiAlO{sub 2} to {alpha}-LiAlO{sub 2} and {gamma}-LiAlO{sub 2}, respectively) of these powders and matrices also occurred, and {gamma}-LiAlO{sub 2} made the third phase like LiAl{sub 5}O{sub 8}. By contrast, the sizes of these particles and the crystalline phase of {alpha}-LiAlO{sub 2} did not change during immersion tests. These results show that, among {alpha}-/{beta}- and {gamma}-LiAlO{sub 2}, {alpha}-LiAlO{sub 2} is the most stable phase in molten carbonate. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  16. Dual mode diffraction phase microscopy for quantitative functional assessment of biological cells

    Science.gov (United States)

    Talaikova, N. A.; Popov, A. P.; Kalyanov, A. L.; Ryabukho, V. P.; Meglinski, I. V.

    2017-10-01

    A diffraction phase microscopy approach with a combined use of transmission and reflection imaging modes has been developed and applied for non-invasive quantitative assessment of the refractive index of red blood cells (RBCs). We present the theoretical background of signal formation for both imaging modes, accompanied by the results of experimental studies. We demonstrate that simultaneous use of the two modes has great potential for accurate assessment of the refractive index of biological cells, and we perform a reconstruction of spatial distribution of the refractive index of RBC in 3D.

  17. Effect of platelet lysate on human cells involved in different phases of wound healing.

    Directory of Open Access Journals (Sweden)

    Maria Chiara Barsotti

    Full Text Available BACKGROUND: Platelets are rich in mediators able to positively affect cell activity in wound healing. Aim of this study was to characterize the effect of different concentrations of human pooled allogeneic platelet lysate on human cells involved in the different phases of wound healing (inflammatory phase, angiogenesis, extracellular matrix secretion and epithelialization. METHODOLOGY/PRINCIPAL FINDINGS: Platelet lysate effect was studied on endothelial cells, monocytes, fibroblasts and keratinocytes, in terms of viability and proliferation, migration, angiogenesis, tissue repair pathway activation (ERK1/2 and inflammatory response evaluation (NFκB. Results were compared both with basal medium and with a positive control containing serum and growth factors. Platelet lysate induced viability and proliferation at the highest concentrations tested (10% and 20% v/v. Whereas both platelet lysate concentrations increased cell migration, only 20% platelet lysate was able to significantly promote angiogenic activity (p<0.05 vs. control, comparably to the positive control. Both platelet lysate concentrations activated important inflammatory pathways such as ERK1/2 and NFκB with the same early kinetics, whereas the effect was different for later time-points. CONCLUSION/SIGNIFICANCE: These data suggest the possibility of using allogeneic platelet lysate as both an alternative to growth factors commonly used for cell culture and as a tool for clinical regenerative application for wound healing.

  18. Detection and specifity of class specific antibodies to whole bacteria cells using a solid phase radioimmunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Czerkinsky, C.; Rees, A.S.; Bergimeier, L.A.; Challacombe, S.J. (Guy' s Hospital Medical and Dental Schools, London (UK))

    1983-07-01

    A solid phase radioimmunoassay has been developed which can be used for the detection of isotype specific antibodies to whole bacteria and other particulate antigens, and is applicable to a variety of species. Bacteria are bound to the solid phase by the use either of antibodies, or of methyl glyoxal. Both methods result in a sensitive and reproducible assay, and bacteria do not appear to desorb from the solid phase. The specificity of antibodies to whole bacteria was examined by absorption of antisera with various species of bacteria and retesting, or by determining the binding of antisera to various bacteria bound to the solid phase. Both methods revealed specificity for the bacteria examined. Inhibition studies showed that antibodies to Streptococcus mutans whole cells could be inhibited by purified cell surface antigens glucosyltransferase and antigen I/II, but only minimally by lipoteichoic acid, c polysaccharide or dextran. In murine antisera antibodies of the IgG, IgM, and IgA classes could be detected at amounts of less than 1 ng/ml.

  19. Cell death and cell proliferation in mouse submandibular gland during early post-irradiation phase.

    Directory of Open Access Journals (Sweden)

    Bralic,Marina

    2005-08-01

    Full Text Available

    The effects of irradiation on different cell compartments in the submandibular gland were analyzed in adult C57BL/6 mice exposed to X-ray irradiation and followed up for 10 days. Apoptosis was quantified using the terminal deoxynucleotidyl transferase (TdT-mediated dUTP-digoxigenin nick end labeling method (TUNEL. Cell proliferation was detected using immunohistochemistry for proliferating cell nuclear antigen (PCNA. Radiation-induced apoptosis occurred rapidly, reaching a maximum 3 days post-irradiation. The percentage of apoptotic cells increased with the irradiation dose. At day 1 post-irradiation, cell proliferation was significantly reduced in comparison to sham-irradiated controls. After post-irradiation arrest of the cell cycle, proliferation increased in all gland compartments, reaching a maximum at day 6 post-irradiation. The proliferation response corresponded to the dose of irradiation. We suggest that the reason for gland dysfunction could be the coexistence of high apoptotic and proliferative activity in the irradiated gland.

  20. Mixed phase Pt-Ru catalyst for direct methanol fuel cell anode by flame aerosol synthesis

    DEFF Research Database (Denmark)

    Chakraborty, Debasish; Bischoff, H.; Chorkendorff, Ib

    2005-01-01

    A spray-flame aerosol catalyzation technique was studied for producing Pt-Ru anode electrodes for the direct methanol fuel cell. Catalysts were produced as aerosol nanoparticles in a spray-flame reactor and deposited directly as a thin layer on the gas diffusion layer. The as-prepared catalyst......Ru1/Vulcan carbon. The kinetics of methanol oxidation on the mixed phase catalyst was also explored by electrochemical impedance spectroscopy. (c) 2005 The Electrochemical Society....

  1. PLK1 blockade enhances therapeutic effects of radiation by inducing cell cycle arrest at the mitotic phase.

    Science.gov (United States)

    Inoue, Minoru; Yoshimura, Michio; Kobayashi, Minoru; Morinibu, Akiyo; Itasaka, Satoshi; Hiraoka, Masahiro; Harada, Hiroshi

    2015-10-27

    The cytotoxicity of ionizing radiation depends on the cell cycle phase; therefore, its pharmacological manipulation, especially the induction of cell cycle arrest at the radiosensitive mitotic-phase (M-phase), has been attempted for effective radiation therapy. Polo-like kinase 1 (PLK1) is a serine/threonine kinase that functions in mitotic progression, and is now recognized as a potential target for radiosensitization. We herein investigated whether PLK1 blockade enhanced the cytotoxic effects of radiation by modulating cell cycle phases of cancer cells using the novel small molecule inhibitor of PLK1, TAK-960. The TAK-960 treatment exhibited radiosensitizing effects in vitro, especially when it increased the proportion of M-phase cells. TAK-960 did not sensitize cancer cells to radiation when an insufficient amount of time was provided to induce mitotic arrest. The overexpression of a PLK1 mutant, PLK1-R136G&T210D, which was confirmed to cancel the TAK-960-mediated increase in the proportion of mitotic cells, abrogated the radiosensitizing effects of TAK-960. A tumor growth delay assay also demonstrated that the radiosensitizing effects of TAK-960 depended on an increase in the proportion of M-phase cells. These results provide a rational basis for targeting PLK1 for radiosensitization when considering the therapeutic time window for M-phase arrest as the best timing for radiation treatments.

  2. Nitric oxide gas phase release in human small airway epithelial cells

    Directory of Open Access Journals (Sweden)

    Suresh Vinod

    2009-01-01

    Full Text Available Abstract Background Asthma is a chronic airway inflammatory disease characterized by an imbalance in both Th1 and Th2 cytokines. Exhaled nitric oxide (NO is elevated in asthma, and is a potentially useful non-invasive marker of airway inflammation. However, the origin and underlying mechanisms of intersubject variability of exhaled NO are not yet fully understood. We have previously described NO gas phase release from normal human bronchial epithelial cells (NHBEs, tracheal origin. However, smaller airways are the major site of morbidity in asthma. We hypothesized that IL-13 or cytomix (IL-1β, TNF-α, and IFN-γ stimulation of differentiated small airway epithelial cells (SAECs, generation 10–12 and A549 cells (model cell line of alveolar type II cells in culture would enhance NO gas phase release. Methods Confluent monolayers of SAECs and A549 cells were cultured in Transwell plates and SAECs were allowed to differentiate into ciliated and mucus producing cells at an air-liquid interface. The cells were then stimulated with IL-13 (10 ng/mL or cytomix (10 ng/mL for each cytokine. Gas phase NO release in the headspace air over the cells was measured for 48 hours using a chemiluminescence analyzer. Results In contrast to our previous result in NHBE, baseline NO release from SAECs and A549 is negligible. However, NO release is significantly increased by cytomix (0.51 ± 0.18 and 0.29 ± 0.20 pl.s-1.cm-2, respectively reaching a peak at approximately 10 hours. iNOS protein expression increases in a consistent pattern both temporally and in magnitude. In contrast, IL-13 only modestly increases NO release in SAECs reaching a peak (0.06 ± 0.03 pl.s-1.cm-2 more slowly (30 to 48 hours, and does not alter NO release in A549 cells. Conclusion We conclude that the airway epithelium is a probable source of NO in the exhaled breath, and intersubject variability may be due, in part, to variability in the type (Th1 vs Th2 and location (large vs small airway

  3. Impact of frequency modulation ratio on capacitor cells balancing in phase-shifted PWM based chain-link STATCOM

    DEFF Research Database (Denmark)

    Behrouzian, Ehsan; Bongiorno, Massimo; Teodorescu, Remus

    2014-01-01

    The purpose of this paper is to investigate the impact of switching harmonics on the instantaneous power that flows in the cells of a chain-link based STATCOM when using Phase-Shifted PWM. Two different cases are investigated for the converter cells: low, and high switching frequency. It is shown...... distribution among cells of the same phase leg, thus contributing to the capacitors balancing. Theoretical conclusions are validated through PSCAD simulation results....

  4. High resolution quantitative phase imaging of live cells with constrained optimization approach

    Science.gov (United States)

    Pandiyan, Vimal Prabhu; Khare, Kedar; John, Renu

    2016-03-01

    Quantitative phase imaging (QPI) aims at studying weakly scattering and absorbing biological specimens with subwavelength accuracy without any external staining mechanisms. Use of a reference beam at an angle is one of the necessary criteria for recording of high resolution holograms in most of the interferometric methods used for quantitative phase imaging. The spatial separation of the dc and twin images is decided by the reference beam angle and Fourier-filtered reconstructed image will have a very poor resolution if hologram is recorded below a minimum reference angle condition. However, it is always inconvenient to have a large reference beam angle while performing high resolution microscopy of live cells and biological specimens with nanometric features. In this paper, we treat reconstruction of digital holographic microscopy images as a constrained optimization problem with smoothness constraint in order to recover only complex object field in hologram plane even with overlapping dc and twin image terms. We solve this optimization problem by gradient descent approach iteratively and the smoothness constraint is implemented by spatial averaging with appropriate size. This approach will give excellent high resolution image recovery compared to Fourier filtering while keeping a very small reference angle. We demonstrate this approach on digital holographic microscopy of live cells by recovering the quantitative phase of live cells from a hologram recorded with nearly zero reference angle.

  5. Multistage aqueous two-phase extraction of a monoclonal antibody from cell supernatant.

    Science.gov (United States)

    Muendges, Jan; Zalesko, Alexej; Górak, Andrzej; Zeiner, Tim

    2015-01-01

    This article presents results of continuous multistage aqueous two-phase extraction of an immunoglobulin G1 from cell supernatant in a mixer-settler unit. An aqueous two-phase system consisting of polyethylene glycol 2000, phosphate salt, and water was applied without and with sodium chloride (NaCl). Influences of different parameters such as throughput, phase ratio, and stage number on the extraction performance were analyzed. For systems without NaCl, the extraction was carried out as a washing step. An increase of stage number from one to five stages enabled to increase the immunoglobulin G1 purity from 11.8 to 32.6% at a yield of nearly 90%. Furthermore, a reduction of product phase volume due to a higher phase ratio led to an increase of purity from 20.8 to 29.6% in a three-stage countercurrent extraction. For experiments with NaCl moderate partitioning conditions were adjusted by adding 8 wt% NaCl. In that case, the extraction was carried out as a stripping step.

  6. Magnetotelluric sounding results in eastern Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    马晓冰; 孔祥儒; 刘宏兵; 闫永利

    2001-01-01

    The results of Zayu-Qingshuihe MT sounding profile carried out in eastern Tibetan Plateau are presented in this paper. Using 2-D RRI method, the resistivity distribution with depth is obtained along the profile. It is featured by the resistivity zones in the horizontal direction and layers in the vertical direction. The Bangong-Nujiang suture zone and Jinshajiang suture zone are both important electrical conductivity-separating zones in the plateau, and the former is a zone with relatively low resistivity while the latter is an electrical conductivity gradient zone. The highly electrical conductive bodies in the mid and lower crust of northern Qiangtang and Bayan Har Terrain might be caused by regional melting due to shear heating during the process of subduction in tectonic evolution.

  7. Biochemical DSB-repair model for mammalian cells in G1 and early S phases of the cell cycle.

    Science.gov (United States)

    Taleei, Reza; Nikjoo, Hooshang

    2013-08-30

    The paper presents a model of double strand breaks (DSB) repair in G1 and early S phases of the cell cycle. The model is based on a plethora of published information on biochemical modification of DSB induced by ionizing radiation. So far, three main DSB repair pathways have been identified, including nonhomologous end-joining (NHEJ), homologous recombination (HR), and microhomology-mediated end-joining (MMEJ). During G1 and early S phases of the cell cycle, NHEJ and MMEJ repair pathways are activated dependent on the type of double strand breaks. Simple DSB are a substrate for NHEJ, while complex DSB and DSB in heterochromatin require further end processing. Repair of all DSB start with NHEJ presynaptic processes, and depending on the type of DSB pursue simple ligation, further end processing prior to ligation, or resection. Using law of mass action the model is translated into a mathematical formalism. The solution of the formalism provides the step by step and overall repair kinetics. The overall repair kinetics are compared with the published experimental measurements. Our calculations are in agreement with the experimental results and show that the complex types of DSBs are repaired with slow repair kinetics. The G1 and early S phase model could be employed to predict the kinetics of DSB repair for damage induced by high LET radiation.

  8. Characterization of functionally active interleukin-18/eGFP fusion protein expression during cell cycle phases in recombinant chicken DF1 Cells.

    Science.gov (United States)

    Wu, Hsing Chieh; Chen, Yu San; Shien, Jui Hung; Shen, Pin Chun; Lee, Long Huw

    2016-05-01

    The dependence of foreign gene expression on cell cycle phases in mammalian cells has been described. In this study, a DF1/chIL-18a cell line that stably expresses the fusion protein chIL-18 was constructed and the enhanced green fluorescence protein connected through a (G4 S)3 linker sequence investigated the relationship between cell cycle phases and fusion protein production. DF1/chIL-18a cells (1 × 10(5) ) were inoculated in 60-mm culture dishes containing 5 mL of media to achieve 50%-60% confluence and were cultured in the presence of the cycle-specific inhibitors 10058-F4, aphidicolin, and colchicine for 24 and 48 h. The percentage of cell density and mean fluorescence intensity in each cell cycle phase were assessed using flow cytometry. The inhibitors effectively arrested cell growth. The fusion protein production rate was higher in the S phase than in the G0/G1 and G2/M phases. When cell cycle progression was blocked in the G0/G1, S, and G2/M phases by the addition of 10058-F4, aphidicolin, and colchicine, respectively, the aphidicolin-induced single cells showed higher fusion protein levels than did the 10058-F4- or colchicine-induced phase cells and the uninduced control cells. Although the cells did not proliferate after the drug additions, the amount of total fusion protein accumulated in aphidicolin-treated cells was similar to that in the untreated cultures. Fusion protein is biologically active because it induces IFN-γ production in splenocyte cultures of chicken. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:581-591, 2016.

  9. A plateau in the sensitivity of a compact optically pumped atomic magnetometer

    Directory of Open Access Journals (Sweden)

    Natsuhiko Mizutani

    2014-05-01

    Full Text Available In a compact optically pumped atomic magnetometer (OPAM, there is a plateau in the sensitivity where the dependence of the sensitivity on pumping power is small compared with that predicted by the uniform polarization model. The mechanism that generates this plateau was explained by numerical analysis. The distribution of spin polarization in the alkali metal cell of an OPAM was modeled using the Bloch equation incorporating a diffusion term and an equation for the attenuation of the pump beam. The model was well-fitted to the experimental results for a module with a cubic cell with 20 mm sides and pump and probe beams with 8 mm diameter. On the plateau, strong magnetic response was generated at the regions that were not illuminated directly by the intense pump beam, while at the same time spin polarization as large as 0.5 was maintained due to diffusion of the spin-polarized atoms. Thus, the sensitivity of the magnetometer monitored with a probe beam decreases only slightly with increasing pump beam intensity because the spin polarization under an intense pump beam is saturated. This plateau, which is characteristic of this type of magnetometer using a narrow pump and probe beams, can be used in arrays of magnetometers because it enables stable operation with little sensitivity fluctuation from changes in pump beam power.

  10. A model of cell biological signaling predicts a phase transition of signaling and provides mathematical formulae.

    Science.gov (United States)

    Tsuruyama, Tatsuaki

    2014-01-01

    A biological signal is transmitted by interactions between signaling molecules in the cell. To date, there have been extensive studies regarding signaling pathways using numerical simulation of kinetic equations that are based on equations of continuity and Fick's law. To obtain a mathematical formulation of cell signaling, we propose a stability kinetic model of cell biological signaling of a simple two-parameter model based on the kinetics of the diffusion-limiting step. In the present model, the signaling is regulated by the binding of a cofactor, such as ATP. Non-linearity of the kinetics is given by the diffusion fluctuation in the interaction between signaling molecules, which is different from previous works that hypothesized autocatalytic reactions. Numerical simulations showed the presence of a critical concentration of the cofactor beyond which the cell signaling molecule concentration is altered in a chaos-like oscillation with frequency, which is similar to a discontinuous phase transition in physics. Notably, we found that the frequency is given by the logarithm function of the difference of the outside cofactor concentration from the critical concentration. This implies that the outside alteration of the cofactor concentration is transformed into the oscillatory alteration of cell inner signaling. Further, mathematical stability kinetic analysis predicted a discontinuous dynamic phase transition in the critical state at which the cofactor concentration is equivalent to the critical concentration. In conclusion, the present model illustrates a unique feature of cell signaling, and the stability analysis may provide an analytical framework of the cell signaling system and a novel formulation of biological signaling.

  11. ZGDHu-1 induces G2/M phase arrest and apoptosis in Kasumi-1 cells

    Science.gov (United States)

    XIA, JUN; CHEN, SU-FENG; LV, YA-PING; LU, LING-NA; HU, WEI-XIAO; ZHOU, YONG-LIE

    2015-01-01

    The present study examined the effects of N,N′-di-(m-methylphenyi)-3, 6-dimethyl-1, 4-dihydro-1,2,4,5-tetrazine-1,4-dicarboamide (ZGDHu-1), a novel oxazine derivative, in Kasumi-1 cells. Following incubation with various concentrations of ZGDHu-1, fluorescence-activated cell sorting (FACS) was used in order to detect changes in mitochondrial membrane permeability in Kasumi-1 cells. Western blot analysis was performed in order to analyze the expression of nuclear factor-κB, inhibitor of κB and AML1/ETO. In addition FACS was used to analyze leukemia cell cycles and the expression levels of cyclin, cyclin-dependent kinases and cyclin-dependent kinase inhibitors in G2/M phase were determined using FACS and western blot analysis. The upregulation of reactive oxygen species production and mitochondrial membrane permeability was ascribed to apoptosis. The growth of Kasumi-1 cells was inhibited through the downregulation of nuclear factor-κB, degradation of AML1/ETO fusion protein and cell cycle arrest at the G2/M phase. This study documented that G2/M regulatory molecules, including cyclin B1, cell division control (cdc)2 and cdc25c were downregulated and checkpoint kinase 1 (CHK1), p53, p27, phospho-cdc25c, phospho-CHK1 and phospho-p53 were upregulated following treatment with ZGDHu-1. In the present study, pretreatment with CHIR-124, a selective CHK1 inhibitor, abrogated G2/M arrest via ZGDHu-1. These results demonstrated the anti-tumor activity of ZGDHu-1, which may therefore a potential target for further investigation and may be useful for the treatment of patients with t(8;21) acute myeloid leukemia. PMID:25573277

  12. ZGDHu-1 induces G₂/M phase arrest and apoptosis in Kasumi-1 cells.

    Science.gov (United States)

    Xia, Jun; Chen, Su-Feng; Lv, Ya-Ping; Lu, Ling-Na; Hu, Wei-Xiao; Zhou, Yong-Lie

    2015-05-01

    The present study examined the effects of N,N'‑di‑(m‑methylphenyi)‑3, 6‑dimethyl‑1, 4‑dihydro‑1,2,4,5‑tetrazine‑1,4‑dicarboamide (ZGDHu‑1), a novel oxazine derivative, in Kasumi‑1 cells. Following incubation with various concentrations of ZGDHu‑1, fluorescence‑activated cell sorting (FACS) was used in order to detect changes in mitochondrial membrane permeability in Kasumi‑1 cells. Western blot analysis was performed in order to analyze the expression of nuclear factor‑κB, inhibitor of κB and AML1/ETO. In addition FACS was used to analyze leukemia cell cycles and the expression levels of cyclin, cyclin‑dependent kinases and cyclin‑dependent kinase inhibitors in G2/M phase were determined using FACS and western blot analysis. The upregulation of reactive oxygen species production and mitochondrial membrane permeability was ascribed to apoptosis. The growth of Kasumi‑1 cells was inhibited through the downregulation of nuclear factor‑κB, degradation of AML1/ETO fusion protein and cell cycle arrest at the G2/M phase. This study documented that G2/M regulatory molecules, including cyclin B1, cell division control (cdc)2 and cdc25c were downregulated and checkpoint kinase 1 (CHK1), p53, p27, phospho‑cdc25c, phospho‑CHK1 and phospho‑p53 were upregulated following treatment with ZGDHu‑1. In the present study, pretreatment with CHIR‑124, a selective CHK1 inhibitor, abrogated G2/M arrest via ZGDHu‑1. These results demonstrated the anti‑tumor activity of ZGDHu‑1, which may therefore a potential target for further investigation and may be useful for the treatment of patients with t(8;21) acute myeloid leukemia.

  13. The property, age and formation environment of the palaeokarst in Qinghai-Xizang Plateau

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The karst landforms distributed on the Qinghai-Xizang (Tibet) Plateau can be genetically classed with the Tertiary underground karst, which were gradually exhumed to the surface with the uplift of the plateau during Quaternary period. The relative deposits of the Tertiary palaeokarst processes, such as the residuum and speleothem, were discovered recently in the southern and southeastern fringe areas of the plateau, where has geological-currently been disintegrated by the headward erosion processes of the modern river systems. The major chemical components of the clay portion of the residuum consist mainly of SiO2, Al2O3 and Fe2O3. The clay minerals composition of the clay portion belongs to illite-kaolinite pattern for most of the residuum samples, and kaoliniteillite pattern for a few of the samples. It can be judged from the silicic acid index and the clay minerals composition that the formation of the residuum of the Plateau was in its initial phase.However, such a lower chemical weathering index only reflected the weathering degree in the bottom or lower parts of the lateritic weathering crust. The relatively intensive chemical weathering processes of the surface layers of the lateritic weathering crust could be logically speculated. The surface feature textures of quartz grains in the residuum were formed mainly by the chemical erosion, which revealed a long-term humid-tropical environment when the residuum and the palaeokarst formed.

  14. Ferromagnetic–ferromagnetic–antiferromagnetic–antiferromagnetic correlation and magnetization plateau in spin-1/2 J{sub 1}–J{sub 1}–J{sub 2}–J{sub 2} tetrameric chains

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Xiao-Yan [Graduate School, Tianjin Polytechnic University, Tianjin 300387 (China); Dou, Jun-Ya [Department of Physics, Tianjin Polytechnic University, Tianjin 300387 (China); Liu, Guang-Hua, E-mail: liuguanghua@tjpu.edu.cn [Department of Physics, Tianjin Polytechnic University, Tianjin 300387 (China)

    2015-10-15

    The magnetization process of a spin-1/2 J{sub 1}–J{sub 1}–J{sub 2}–J{sub 2} tetrameric Heisenberg chain is investigated by the infinite time-evolving block decimation (iTEBD) method. A magnetization phase diagram including three different phases, i.e., a fully polarized (FP) phase, a 1/2 plateau phase, and a spin-fluid (SF) phase, is obtained. All the quantum phase transitions (QPTs) are determined to belong to the second-order category, and the central charge in the critical SF phase equals 1. In addition, a 1/2 plateau phase also exists in the classical J{sub 1}–J{sub 1}–J{sub 2}–J{sub 2} tetrameric Ising chain. The F–F–AF–AF (or AF–AF–F–F) type longitudinal correlation is found to be important and necessary for the appearance of the 1/2 plateau state in both quantum and classical cases. - Highlights: • 1/2 magnetization plateau can be realized in both quantum and classical cases. • 1/2 plateau is characterized by constant magnetization, entanglement and correlation. • Central charge of the spin-fluid phase is determined to be 1. • F–F–AF–AF correlation is important for the appearance of the 1/2 plateau.

  15. Light and Electrically Induced Phase Segregation and Its Impact on the Stability of Quadruple Cation High Bandgap Perovskite Solar Cells.

    Science.gov (United States)

    Duong, The; Mulmudi, Hemant Kumar; Wu, YiLiang; Fu, Xiao; Shen, Heping; Peng, Jun; Wu, Nandi; Nguyen, Hieu T; Macdonald, Daniel; Lockrey, Mark; White, Thomas P; Weber, Klaus; Catchpole, Kylie

    2017-08-16

    Perovskite material with a bandgap of 1.7-1.8 eV is highly desirable for the top cell in a tandem configuration with a lower bandgap bottom cell, such as a silicon cell. This can be achieved by alloying iodide and bromide anions, but light-induced phase-segregation phenomena are often observed in perovskite films of this kind, with implications for solar cell efficiency. Here, we investigate light-induced phase segregation inside quadruple-cation perovskite material in a complete cell structure and find that the magnitude of this phenomenon is dependent on the operating condition of the solar cell. Under short-circuit and even maximum power point conditions, phase segregation is found to be negligible compared to the magnitude of segregation under open-circuit conditions. In accordance with the finding, perovskite cells based on quadruple-cation perovskite with 1.73 eV bandgap retain 94% of the original efficiency after 12 h operation at the maximum power point, while the cell only retains 82% of the original efficiency after 12 h operation at the open-circuit condition. This result highlights the need to have standard methods including light/dark and bias condition for testing the stability of perovskite solar cells. Additionally, phase segregation is observed when the cell was forward biased at 1.2 V in the dark, which indicates that photoexcitation is not required to induce phase segregation.

  16. A phase synchronization clustering algorithm for identifying interesting groups of genes from cell cycle expression data

    Directory of Open Access Journals (Sweden)

    Tcha Hong

    2008-01-01

    Full Text Available Abstract Background The previous studies of genome-wide expression patterns show that a certain percentage of genes are cell cycle regulated. The expression data has been analyzed in a number of different ways to identify cell cycle dependent genes. In this study, we pose the hypothesis that cell cycle dependent genes are considered as oscillating systems with a rhythm, i.e. systems producing response signals with period and frequency. Therefore, we are motivated to apply the theory of multivariate phase synchronization for clustering cell cycle specific genome-wide expression data. Results We propose the strategy to find groups of genes according to the specific biological process by analyzing cell cycle specific gene expression data. To evaluate the propose method, we use the modified Kuramoto model, which is a phase governing equation that provides the long-term dynamics of globally coupled oscillators. With this equation, we simulate two groups of expression signals, and the simulated signals from each group shares their own common rhythm. Then, the simulated expression data are mixed with randomly generated expression data to be used as input data set to the algorithm. Using these simulated expression data, it is shown that the algorithm is able to identify expression signals that are involved in the same oscillating process. We also evaluate the method with yeast cell cycle expression data. It is shown that the output clusters by the proposed algorithm include genes, which are closely associated with each other by sharing significant Gene Ontology terms of biological process and/or having relatively many known biological interactions. Therefore, the evaluation analysis indicates that the method is able to identify expression signals according to the specific biological process. Our evaluation analysis also indicates that some portion of output by the proposed algorithm is not obtainable by the traditional clustering algorithm with

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

  18. Harmonizing HeLa cell cytoskeleton behavior by multi-Ti oxide phased nanostructure synthesized through ultrashort pulsed laser.

    Science.gov (United States)

    Chinnakkannu Vijayakumar, Chandramouli; Venkatakrishnan, Krishnan; Tan, Bo

    2015-10-15

    Knowledge about cancer cell behavior on heterogeneous nanostructures is relevant for developing a distinct biomaterial that can actuate cancer cells. In this manuscript, we have demonstrated a harmonized approach of forming multi Ti-oxide phases in a nanostructure (MTOP nanostructure) for its unique cancer cell controlling behavior.Conventionally, single phases of TiO2 are used for targeted therapy and as drug carrier systems.In this research, we have shown a biomaterial that can control HeLa cells diligently using a combination of TiO, Ti3O and TiO2 phases when compared to fibroblast (NIH3T3) cells.MTOP-nanostructures are generated by varying the ionization energy in the vapor plume of the ultrashort pulse laser; this interaction with the material allows accurate tuning and composition of phases within the nanostructure. In addition, the lattice spacing of MTOP-nanostructures was analyzed as shown by HR-TEM investigations. An FESEM investigation of MTOP-nanostructures revealed a greater reduction of HeLa cells relative to fibroblast cells. Altered cell adhesion was followed by modulation of HeLa cell architecture with a significant reduction of actin stress fibers.The intricate combination of MTOP-nanostructures renders a biomaterial that can precisely alter HeLa cell but not fibroblast cell behavior, filling a void in the research for a biomaterial to modulate cancer cell behavior.

  19. Harmonizing HeLa cell cytoskeleton behavior by multi-Ti oxide phased nanostructure synthesized through ultrashort pulsed laser

    Science.gov (United States)

    Chinnakkannu Vijayakumar, Chandramouli; Venkatakrishnan, Krishnan; Tan, Bo

    2015-10-01

    Knowledge about cancer cell behavior on heterogeneous nanostructures is relevant for developing a distinct biomaterial that can actuate cancer cells. In this manuscript, we have demonstrated a harmonized approach of forming multi Ti-oxide phases in a nanostructure (MTOP nanostructure) for its unique cancer cell controlling behavior.Conventionally, single phases of TiO2 are used for targeted therapy and as drug carrier systems.In this research, we have shown a biomaterial that can control HeLa cells diligently using a combination of TiO, Ti3O and TiO2 phases when compared to fibroblast (NIH3T3) cells.MTOP-nanostructures are generated by varying the ionization energy in the vapor plume of the ultrashort pulse laser; this interaction with the material allows accurate tuning and composition of phases within the nanostructure. In addition, the lattice spacing of MTOP-nanostructures was analyzed as shown by HR-TEM investigations. An FESEM investigation of MTOP-nanostructures revealed a greater reduction of HeLa cells relative to fibroblast cells. Altered cell adhesion was followed by modulation of HeLa cell architecture with a significant reduction of actin stress fibers.The intricate combination of MTOP-nanostructures renders a biomaterial that can precisely alter HeLa cell but not fibroblast cell behavior, filling a void in the research for a biomaterial to modulate cancer cell behavior.

  20. [Phase III clinical trial using autologous mesenchymal stem cells for stroke patients].

    Science.gov (United States)

    Honmou, Osamu

    2016-04-01

    We conduct a double-blind randomized placebo-controlled clinical trial (Phase III: confirmatory trial) of intravenous infusion of autologous mesenchymal stem cells for cerebral infarction patients. The objectives of this study were to examine feasibility, safety, and efficacy of cell therapy using auto serum-expanded autologous mesenchymal stem cells derived from bone marrow in the stroke patients. Inclusion criteria is (1) Cerebral infarction onset within 40 days, (2) Supra-tentorial cerebral infarction(NINDS-III 1990) diagnosed by MRI(or CT), MRA (3D-CTA or DSA), ECG, chest X-ray etc., (3) Classified under grade 4 or 5 of mRS (modified Rankin scale), (4) Age between 20 to 80, (5) The written informed consent from subjects and legal representative is provided.

  1. The crustal composition of the Falkland Plateau

    Science.gov (United States)

    Klemt, Claudia; Jokat, Wilfried

    2015-04-01

    The Falkland Islands are situated in the South Atlantic Ocean 500 km east of Patagonia, South America. The islands are part of the Falkland Plateau, which stretches eastward for more than 1500 km. A bathymetric high, the Maurice Ewing Bank, terminates the plateau in the east. Until Late Jurassic the Falkland Islands were part of Gondwana and were located adjacent to the east coast of South Africa. While the Falkland Islands and Maurice Ewing Bank are proved to be of continental composition, the nature and structure of the Falkland Plateau's basement in between is debatable. The first crustal model derived from sonobuoy data contradicts an only recently published 3D-gravity model. To enhance the understanding of Gondwana break-up considering timing, geometry and amount of volcanism, further knowledge about the structure and thickness of the crust is inevitable. During the ANT-XXIX/5 Polarstern cruise seismic refraction measurements were conducted using Ocean Bottom Seismometers (OBS) and Reftek land stations onshore of East Falkland. The OBS were deployed at 78 locations along an approximately 1500 km east-west stretching profile. For the western transect a P-wave velocity model is calculated using 2D-raytracing techniques. The results are presented in combination with potential field data showing the extension of the Falkland Islands basement, the continent-ocean transition zone and the crustal structure of the plateau. On the Falkland Plateau Basin sediment thickness is about 6 km with velocities ranging from 1.7 to 4.1 km/s in the upper part and about 4.7 km/s above basement. The crust is of oceanic composition with an igneous section that is considerably thicker than average oceanic crust (up to 17 km). The velocity structure in the upper crustal part is typical for layer 2 with a velocity gradient ranging from 5.4 km/s to 6.5 km/s and thicknesses between 1.5 km and 4 km. Layer 3 is about 14 km thick with a velocity gradient from 6.6 km/s to 7.6 km/s, which is

  2. Assessment of cell cycle phase-specific effects of zerumbone on mitotically synchronous surface cultures of Physarum polycephalum.

    Science.gov (United States)

    Rajan, Iyyappan; Rabindran, Remitha; Nithya, N; Lakshmipriya, T; Jayasree, P R; Kumar, P R M

    2014-07-01

    Zerumbone, a natural cyclic sesquiterpene, has been the focus of recent research as it has been found to exhibit selective toxicity towards cancer cells compared to normal cells. Studies on the cell cycle phase-specific effects of this interesting compound, however, remain sparse. Hence, concentration and time-dependent effects of zerumbone were evaluated employing a suitable model system, the naturally synchronous surface cultures of Physarum polycephalum. Zerumbone treatment in S, early, and late G2 phases resulted in G2 arrest. Early G2 phase exhibited the highest sensitivity (P polycephalum.

  3. Cognitive flexibility during breath alcohol plateau is associated with previous drinking measures.

    Science.gov (United States)

    Lewis, Ben; Nixon, Sara Jo

    2013-06-01

    Although the biphasic effects of acute alcohol during ascending and descending Breath Alcohol Concentrations (BrACs) are well described, the plateau period between peak and steadily descending BrACs is generally unrecognized and under-studied by researchers. Naturalistic examinations indicate such periods persist for substantial intervals, with a time frame of onset suggesting BrAC plateaus may co-occur with potentially risky behaviors (e.g., driving). The current pilot study examined neurocognitive performance during this period. Participants were healthy, community-residing moderate drinkers (n = 18). In the first phase of the study, the Digit Symbol Substitution and Trail Making Tasks were administered during BrAC plateau (M = 62 mg/dL). BrACs were negatively correlated with Digit Symbol performance but unrelated to other tasks. In contrast, performance on a derived Trail Making measure of set-shifting was positively associated with the maximum alcohol doses consumed in the preceding 6 months. Phase 2 analyses demonstrated that relationships between previous alcohol experience and cognitive performance were absent among individuals receiving placebo beverages. Taken together, these data suggest a relationship worthy of investigation between previous drinking experiences and cognitive flexibility during the plateau phase.

  4. Observations of A Low-Velocity Type II-Plateau Supernova 2013am in M65

    CERN Document Server

    Zhang, Jujia; Mazzali, Paolo A; Bai, Jinming; Zhang, Tianmeng; Bersier, David; Huang, Fang; Fan, Yufeng; Mo, Jun; Wang, Jianguo; Yi, Weimin; Wang, Chuanjun; Xin, Yuxin; Liangchang,; Zhang, Xiliang; Lun, Baoli; Wang, Xueli; He, Shousheng; Walker, Emma S

    2014-01-01

    Optical and ultraviolet observations for the nearby type II-plateau supernova (SN IIP) 2013am in the nearby spiral galaxy M65 are presented in this paper. The early spectra are characterized by relatively narrow P-Cygni features, with ejecta velocities much lower than observed in normal SNe IIP (i.e., $\\sim$2000 km s$^{-1}$ vs. $\\sim$5000 km $^{-1}$ in the middle of the plateau phase). Moreover, prominent \\ion{Ca}{2} absorptions are also detected in SN 2013am at relatively early phases. These spectral features are reminiscent of those seen in the low-velocity and low-luminosity SN IIP 2005cs. However, SN 2013am exhibits different photometric properties, having shorter plateau phases and brighter light-curve tails if compared to SN 2005cs. Adopting $R_{V}$=3.1 and a mean value of total reddening derived from the photometric and spectroscopic methods(i.e., $E(B-V)=0.55\\pm$0.19 mag), we find that SN 2013am may have reached an absolute $V$-band peak magnitude of $-15.83\\pm0.71$ mag and produced a $^{56}$Ni mass o...

  5. The effect of the intra-S-phase checkpoint on origins of replication in human cells.

    Science.gov (United States)

    Karnani, Neerja; Dutta, Anindya

    2011-03-15

    Although many chemotherapy drugs activate the intra-S-phase checkpoint pathway to block S-phase progression, not much is known about how and where the intra-S-phase checkpoint regulates origins of replication in human chromosomes. A genomic analysis of replication in human cells in the presence of hydroxyurea (HU) revealed that only the earliest origins fire, but the forks stall within 2 kb and neighboring clusters of dormant origins are activated. The initiation events are located near expressed genes with a preference for transcription start and end sites, and when they are located in intergenic regions they are located near regulatory factor-binding regions (RFBR). The activation of clustered neo-origins by HU suggests that there are many potential replication initiation sites in permissive parts of the genome, most of which are not used in a normal S phase. Consistent with this redundancy, we see multiple sites bound to MCM3 (representative of the helicase) in the region flanking three out of three origins studied in detail. Bypass of the intra-S-phase checkpoint by caffeine activates many new origins in mid- and late-replicating parts of the genome. The intra-S-phase checkpoint suppresses origin firing after the loading of Mcm10, but before the recruitment of Cdc45 and AND-1/CTF4; i.e., after helicase loading but before helicase activation and polymerase loading. Interestingly, Cdc45 recruitment upon checkpoint bypass was accompanied by the restoration of global Cdk2 kinase activity and decrease in both global and origin-bound histone H3 Lys 4 trimethylation (H3K4me3), consistent with the suggestion that both of these factors are important for Cdc45 recruitment.

  6. "Plastic" solar cells: self-assembly of bulk heterojunction nanomaterials by spontaneous phase separation.

    Science.gov (United States)

    Peet, Jeffrey; Heeger, Alan J; Bazan, Guillermo C

    2009-11-17

    As the global demand for low-cost renewable energy sources intensifies, interest in new routes for converting solar energy to electricity is rapidly increasing. Although photovoltaic cells have been commercially available for more than 50 years, only 0.1% of the total electricity generated in the United States comes directly from sunlight. The earliest commercial solar technology remains the basis for the most prevalent devices in current use, namely, highly-ordered crystalline, inorganic solar cells, commonly referred to as silicon cells. Another class of solar cells that has recently inspired significant academic and industrial excitement is the bulk heterojunction (BHJ) "plastic" solar cell. Research by a rapidly growing community of scientists across the globe is generating a steady stream of new insights into the fundamental physics, the materials design and synthesis, the film processing and morphology, and the device science and architecture of BHJ technology. Future progress in the fabrication of high-performance BHJ cells will depend on our ability to combine aspects of synthetic and physical chemistry, condensed matter physics, and materials science. In this Account, we use a combination of characterization tools to tie together recent advances in BHJ morphology characterization, device photophysics, and thin-film solution processing, illustrating how to identify the limiting factors in solar cell performance. We also highlight how new processing methods, which control both the BHJ phase separation and the internal order of the components, can be implemented to increase the power conversion efficiency (PCE). The failure of many innovative materials to achieve high performance in BHJ solar cell devices has been blamed on "poor morphology" without significant characterization of either the structure of the phase-separated morphology or the nature of the charge carrier recombination. We demonstrate how properly controlling the "nanomorphology", which is

  7. InGaAsP Solar Cells Grown by Hydride Vapor Phase Epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Nikhil; Simon, John; Schulte, Kevin L.; Dippo, Patricia; Young, Michelle; Young, David L.; Ptak, Aaron J.

    2016-11-21

    Hydride vapor phase epitaxy (HVPE) has recently reemerged as a low-cost, high-throughput alternative to metalorganic chemical vapor deposition (MOCVD) for the growth of high-efficiency III-V solar cells. Quaternary InGaAsP solar cells in the bandgap range of ~1.7-1.8 eV are promising top-cell candidates for integration in Ill-V/Si tandem cells with projected one-sun efficiencies exceeding 30%. In this work, we report on the development of lattice-matched InGaAsP solar cells grown on GaAs substrates via HVPE at very high growth rates of ~0.7 um/min. We demonstrate prototype 1.7 eV InGaAsP solar cells with an open-circuit voltage of 1.11 V. The short-circuit current is limited by the lack of a window layer in these early stage devices. The photo response of 1.7 InGaAsP solar cell with ~1.1 um thick base layer is found to be nearly insensitive to variation in p-type base doping concentration in the range from Na - 4x1016 to - 1x1017 cm-3, indicating an effective carrier collection length on the order of - 1.1 um or higher in our devices. These initial InGaAsP cell results are encouraging and highlight the viability of HVPE to produce mixed arsenide-phosphide solar cells grown lattice-matched on GaAs.

  8. Fluid phase biopsy for detection and characterization of circulating endothelial cells in myocardial infarction

    Science.gov (United States)

    Bethel, Kelly; Luttgen, Madelyn S.; Damani, Samir; Kolatkar, Anand; Lamy, Rachelle; Sabouri-Ghomi, Mohsen; Topol, Sarah; Topol, Eric J.; Kuhn, Peter

    2014-02-01

    Elevated levels of circulating endothelial cells (CECs) occur in response to various pathological conditions including myocardial infarction (MI). Here, we adapted a fluid phase biopsy technology platform that successfully detects circulating tumor cells in the blood of cancer patients (HD-CTC assay), to create a high-definition circulating endothelial cell (HD-CEC) assay for the detection and characterization of CECs. Peripheral blood samples were collected from 79 MI patients, 25 healthy controls and six patients undergoing vascular surgery (VS). CECs were defined by positive staining for DAPI, CD146 and von Willebrand Factor and negative staining for CD45. In addition, CECs exhibited distinct morphological features that enable differentiation from surrounding white blood cells. CECs were found both as individual cells and as aggregates. CEC numbers were higher in MI patients compared with healthy controls. VS patients had lower CEC counts when compared with MI patients but were not different from healthy controls. Both HD-CEC and CellSearch® assays could discriminate MI patients from healthy controls with comparable accuracy but the HD-CEC assay exhibited higher specificity while maintaining high sensitivity. Our HD-CEC assay may be used as a robust diagnostic biomarker in MI patients.

  9. Ultra-robust high-field magnetization plateau and supersolidity in bond-frustrated MnCr2S4

    Science.gov (United States)

    Tsurkan, Vladimir; Zherlitsyn, Sergei; Prodan, Lilian; Felea, Viorel; Cong, Pham Thanh; Skourski, Yurii; Wang, Zhe; Deisenhofer, Joachim; von Nidda, Hans-Albrecht Krug; Wosnitza, Joahim; Loidl, Alois

    2017-01-01

    Frustrated magnets provide a promising avenue for realizing exotic quantum states of matter, such as spin liquids and spin ice or complex spin molecules. Under an external magnetic field, frustrated magnets can exhibit fractional magnetization plateaus related to definite spin patterns stabilized by field-induced lattice distortions. Magnetization and ultrasound experiments in MnCr2S4 up to 60 T reveal two fascinating features: (i) an extremely robust magnetization plateau with an unusual spin structure and (ii) two intermediate phases, indicating possible realizations of supersolid phases. The magnetization plateau characterizes fully polarized chromium moments, without any contributions from manganese spins. At 40 T, the middle of the plateau, a regime evolves, where sound waves propagate almost without dissipation. The external magnetic field exactly compensates the Cr–Mn exchange field and decouples Mn and Cr sublattices. In analogy to predictions of quantum lattice-gas models, the changes of the spin order of the manganese ions at the phase boundaries of the magnetization plateau are interpreted as transitions to supersolid phases. PMID:28345038

  10. Multidisciplinary scientific program of investigation of the structure and evolution of the Demerara marginal plateau

    Science.gov (United States)

    Loncke, Lies; Basile, Christophe; Roest, Walter; Graindorge, David; Mercier de Lépinay, Marion; Klinghelhoefer, Frauke; Heuret, Arnauld; Pattier, France; Tallobre, Cedric; Lebrun, Jean-Frédéric; Poetisi, Ewald; Loubrieu, Benoît; Iguanes, Dradem, Margats Scientific Parties, Plus

    2017-04-01

    Mercier de Lépinay et al. published in 2016 an updated inventory of transform passive margins in the world. This inventory shows that those margins represent 30% of continental passive margins and a cumulative length of 16% of non-convergent margins. It also highlights the fact that many submarine plateaus prolong transform continental margins, systematically at the junction of oceanic domains of different ages. In the world, we identified twenty of those continental submarine plateaus (Falklands, Voring, Demerara, Tasman, etc). Those marginal plateaus systematically experiment two phases of deformation: a first extensional phase and a second transform phase that allows the individualization of those submarine reliefs appearing on bathymetry as seaward continental-like salients. The understanding of the origin, nature, evolution of those marginal plateaus has many scientific and economic issues. The Demerara marginal plateau located off French Guiana and Surinam belongs to this category of submarine provinces. The French part of this plateau has been the locus of a first investigation in 2003 in the framework of the GUYAPLAC cruise dedicated to support French submissions about extension of the limit of the continental shelf beyond 200 nautical miles. This cruise was the starting point of a scientific program dedicated to geological investigations of the Demerara plateau that was sustained by different cruises and collaborations (1) IGUANES (2013) that completed the mapping of this plateau including off Surinam, allowed to better understand the segmentation of the Northern edge of this plateau, and to evidence the combined importance of contourite and mass-wasting processes in the recent sedimentary evolution of this domain, (2) Collaboration with TOTAL (Mercier de Lépinay's PhD thesis) that allowed to better qualify the two main phases of structural evolution of the plateau respectively during Jurassic times for its Western border, Cretaceous times for its

  11. Where the linearized Poisson-Boltzmann cell model fails: Spurious phase separation in charged colloidal suspensions

    Science.gov (United States)

    Tamashiro, M. N.; Schiessel, H.

    2003-07-01

    The Poisson-Boltzmann (PB) spherical Wigner-Seitz cell model—introduced to theoretically describe suspensions of spherical charged colloidal particles—is investigated at the nonlinear and linearized levels. The linearization of the mean-field PB functional yields linearized Debye-Hückel-type equations agreeing asymptotically with the nonlinear PB results in the weak-coupling (high-temperature) limit. Both the canonical (fixed number of microions) as well as the semigrand-canonical (in contact with an infinite salt reservoir) cases are considered and discussed in a unified linearized framework. In disagreement with the exact nonlinear PB solution inside a Wigner-Seitz cell, the linearized theory predicts the occurrence of a thermodynamical instability with an associated phase separation of the homogeneous suspension into dilute (gas) and dense (liquid) phases, being thus a spurious result of the linearization. We show that these artifacts, although thermodynamically consistent with quadratic expansions of the nonlinear functional and osmotic pressure, may be traced back to the nonfulfillment of the underlying assumptions of the linearization. This raises questions about the reliability of the prediction of gas/liquid-like phase separation in deionized aqueous suspensions of charged colloids mediated by monovalent counterions obtained by linearized theories.

  12. Neisseria meningitidis causes cell cycle arrest of human brain microvascular endothelial cells at S phase via p21 and cyclin G2.

    Science.gov (United States)

    Oosthuysen, Wilhelm F; Mueller, Tobias; Dittrich, Marcus T; Schubert-Unkmeir, Alexandra

    2016-01-01

    Microbial pathogens have developed several mechanisms to modulate and interfere with host cell cycle progression. In this study, we analysed the effect of the human pathogen Neisseria meningitidis on cell cycle in a brain endothelial cell line as well as in primary brain endothelial cells. We found that N.  Meningitidis causes an accumulation of cells in the S phase early at 3 and at 24 h post-infection that was paralleled by a decrease of cells in G2/M phase. Importantly, the outer membrane proteins of the colony opacity-associated (Opa) protein family as well as the Opc protein proved to trigger the accumulation of cells in the S phase. A focused cell cycle reverse transcription quantitative polymerase chain reaction-based array and integrated network analysis revealed changes in the abundance of several cell cycle regulatory mRNAs, including the cell cycle inhibitors p21(WAF1/CIP1) and cyclin G2. These alterations were reflected in changes in protein expression levels and/or relocalization in N. meningitidis-infected cells. Moreover, an increase in p21(WAF1/CIP1) expression was found to be p53 independent. Genetic ablation of p21(WAF1/CIP1) and cyclin G2 abrogated N. meningitidis-induced S phase accumulation. Finally, by measuring the levels of the biomarker 8-hydroxydeoxyguanosine and phosphorylation of the histone variant H2AX, we provide evidence that N. meningitidis induces oxidative DNA damage in infected cells.

  13. Resolution of heterogeneous fluorescence emission signals and decay lifetime measurement on fluorochrome-labeled cells by phase-sensitive FCM

    Energy Technology Data Exchange (ETDEWEB)

    Steinkamp, J.A.; Crissman, H.A.

    1993-02-01

    A phase-sensitive flow cytometer has been developed to resolve signals from heterogeneous fluorescence emission spectra and quantify fluorescence decay times on cells labeled with fluorescent dyes. This instrument combines flow cytometry (FCM) and fluorescence spectroscopy measurement principles to provide unique capabilities for making phase-resolved measurements on single cells in flow, while preserving conventional FCM measurement capabilities. Stained cells are analyzed as they pass through an intensity-modulated (sinusoid) laser excitation beam. Fluorescence is measured orthogonally using a s barrier filter to block scattered laser excitation light, and a photomultiplier tube detector output signals, which are shifted in phase from a reference signal and amplitude demodulated, are processed by phase-sensitive detection electronics to resolve signals from heterogeneous emissions and quantify decay lifetimes directly. The output signals are displayed as frequency distribution histograms and bivariate diagrams using a computer-based data acquisition system. Results have demonstrated signal phase shift, amplitude demodulation, and average measurement of fluorescence lifetimes on stained cells; a detection limit threshold of 300 to 500 fluorescein isothiocyanate (FITC); fluorescence measurement precision of 1.3% on alignment fluorospheres and 3.4% on propidium iodide (PI)-stained cells; the resolution of PI and FITC signals from cells stainedin combination with PI and FITC, based on differences in their decay lifetimes; and the ability to measure single decay nines by the two-phase, phase comparator, method.

  14. Resolution of heterogeneous fluorescence emission signals and decay lifetime measurement on fluorochrome-labeled cells by phase-sensitive FCM

    Energy Technology Data Exchange (ETDEWEB)

    Steinkamp, J.A.; Crissman, H.A.

    1993-01-01

    A phase-sensitive flow cytometer has been developed to resolve signals from heterogeneous fluorescence emission spectra and quantify fluorescence decay times on cells labeled with fluorescent dyes. This instrument combines flow cytometry (FCM) and fluorescence spectroscopy measurement principles to provide unique capabilities for making phase-resolved measurements on single cells in flow, while preserving conventional FCM measurement capabilities. Stained cells are analyzed as they pass through an intensity-modulated (sinusoid) laser excitation beam. Fluorescence is measured orthogonally using a s barrier filter to block scattered laser excitation light, and a photomultiplier tube detector output signals, which are shifted in phase from a reference signal and amplitude demodulated, are processed by phase-sensitive detection electronics to resolve signals from heterogeneous emissions and quantify decay lifetimes directly. The output signals are displayed as frequency distribution histograms and bivariate diagrams using a computer-based data acquisition system. Results have demonstrated signal phase shift, amplitude demodulation, and average measurement of fluorescence lifetimes on stained cells; a detection limit threshold of 300 to 500 fluorescein isothiocyanate (FITC); fluorescence measurement precision of 1.3% on alignment fluorospheres and 3.4% on propidium iodide (PI)-stained cells; the resolution of PI and FITC signals from cells stainedin combination with PI and FITC, based on differences in their decay lifetimes; and the ability to measure single decay nines by the two-phase, phase comparator, method.

  15. Live cell plasma membranes do not exhibit a miscibility phase transition over a wide range of temperatures.

    Science.gov (United States)

    Lee, Il-Hyung; Saha, Suvrajit; Polley, Anirban; Huang, Hector; Mayor, Satyajit; Rao, Madan; Groves, Jay T

    2015-03-26

    Lipid/cholesterol mixtures derived from cell membranes as well as their synthetic reconstitutions exhibit well-defined miscibility phase transitions and critical phenomena near physiological temperatures. This suggests that lipid/cholesterol-mediated phase separation plays a role in the organization of live cell membranes. However, macroscopic lipid-phase separation is not generally observed in cell membranes, and the degree to which properties of isolated lipid mixtures are preserved in the cell membrane remain unknown. A fundamental property of phase transitions is that the variation of tagged particle diffusion with temperature exhibits an abrupt change as the system passes through the transition, even when the two phases are distributed in a nanometer-scale emulsion. We support this using a variety of Monte Carlo and atomistic simulations on model lipid membrane systems. However, temperature-dependent fluorescence correlation spectroscopy of labeled lipids and membrane-anchored proteins in live cell membranes shows a consistently smooth increase in the diffusion coefficient as a function of temperature. We find no evidence of a discrete miscibility phase transition throughout a wide range of temperatures: 14-37 °C. This contrasts the behavior of giant plasma membrane vesicles (GPMVs) blebbed from the same cells, which do exhibit phase transitions and macroscopic phase separation. Fluorescence lifetime analysis of a DiI probe in both cases reveals a significant environmental difference between the live cell and the GPMV. Taken together, these data suggest the live cell membrane may avoid the miscibility phase transition inherent to its lipid constituents by actively regulating physical parameters, such as tension, in the membrane.

  16. Aspartate Rescues S-phase Arrest Caused by Suppression of Glutamine Utilization in KRas-driven Cancer Cells.

    Science.gov (United States)

    Patel, Deven; Menon, Deepak; Bernfeld, Elyssa; Mroz, Victoria; Kalan, Sampada; Loayza, Diego; Foster, David A

    2016-04-22

    During G1-phase of the cell cycle, normal cells respond first to growth factors that indicate that it is appropriate to divide and then later in G1 to the presence of nutrients that indicate sufficient raw material to generate two daughter cells. Dividing cells rely on the "conditionally essential" amino acid glutamine (Q) as an anaplerotic carbon source for TCA cycle intermediates and as a nitrogen source for nucleotide biosynthesis. We previously reported that while non-transformed cells arrest in the latter portion of G1 upon Q deprivation, mutant KRas-driven cancer cells bypass the G1 checkpoint, and instead, arrest in S-phase. In this study, we report that the arrest of KRas-driven cancer cells in S-phase upon Q deprivation is due to the lack of deoxynucleotides needed for DNA synthesis. The lack of deoxynucleotides causes replicative stress leading to activation of the ataxia telangiectasia and Rad3-related protein (ATR)-mediated DNA damage pathway, which arrests cells in S-phase. The key metabolite generated from Q utilization was aspartate, which is generated from a transaminase reaction whereby Q-derived glutamate is converted to α-ketoglutarate with the concomitant conversion of oxaloacetate to aspartate. Aspartate is a critical metabolite for both purine and pyrimidine nucleotide biosynthesis. This study identifies the molecular basis for the S-phase arrest caused by Q deprivation in KRas-driven cancer cells that arrest in S-phase in response to Q deprivation. Given that arresting cells in S-phase sensitizes cells to apoptotic insult, this study suggests novel therapeutic approaches to KRas-driven cancers.

  17. Effect of cell cycle phase on the sensitivity of SAS cells to sonodynamic therapy using low-intensity ultrasound combined with 5-aminolevulinic acid in vitro.

    Science.gov (United States)

    Li, Nan; Sun, Miao; Wang, Yao; Lv, Yanhong; Hu, Zheng; Cao, Wenwu; Zheng, Jinhua; Jiao, Xiaohui

    2015-08-01

    Sonodynamic therapy (SDT) with 5-aminolevulinic acid (5-ALA) can effectively inhibit various types of tumor in vitro and in vivo. However, the association between the efficacy of SDT and the phase of the cell cycle remains to be elucidated. 5-ALA may generate different quantities of sonosensitizer, protoporphyrin IX (PpIX), in different phases of the cell cycle, which may result in differences in sensitivity to 5-ALA-induced SDT. The present study aimed to investigate the effect of the cell cycle on the susceptibility of SAS cells to SDT following synchronization to different cell cycle phases. These results indicates that the rates of cell death and apoptosis of the SAS cells in the S and G2/M phases were significantly higher following SDT, compared with those in the G1-phase cells and unsynchronized cells, with a corresponding increase in PpIX in the S and G2/M cells. In addition, the expression of caspase-3 increased, while that of B-cell lymphoma (Bcl)-2 decreased markedly in theS and G2/M cells following SDT. Cyclin A was also expressed at higher levels in the S and G2/M cells, compared with the G1-phase cells. SDT also caused a significant upregulation of cyclin A in all phases of the cell cycle, however this was most marked in the S and G2/M cells. It was hypothesized that high expression levels of cyclin A in the S and G2/M cells may promote the induction of caspase-3 and reduce the induction of Bcl-2 by SDT and, therefore, enhance apoptosis. Taken together, these data demonstrated that cells in The S and G2/M phases generate more intracellular PpIX, have higher levels of cyclin A and are, therefore, more sensitive to SDT-induced cytotoxicity. These findings indicate the potential novel approach to preventing the onset of cancer by combining cell-cycle regulators with SDT. This sequential combination therapy may be a simple and cost-effective way of enhancing the effects of SDT in clinical settings.

  18. Chemical erosion and hydrologic budget for the Susure karst plateau

    Directory of Open Access Journals (Sweden)

    Nikić Zoran

    2010-01-01

    Full Text Available The karst plateau of Susure, about 4.5 km2 in surface area, is situated on the Jadovnik eastern offset, western Serbia. The plateau is a morphologic unit higher 15 m to 30 m than the surrounding terrain. The unit consists of crushed and karstified Middle Triassic limestones. Numerous hydrogeological and geomorphologic features of the plateau are attractive for visitors in this economically underdeveloped country. Rocks building up the surrounding terrain are largely peridotites. Surface streams flow neither into nor off the plateau. Atmospheric precipitations discharge to evapotanspiration and filtration underground. More than eighteen constant springs at the limestone/peridotite tectonic contact drain fracture aquifers on the karst plateau border. Measured precipitations and springflows were the input and output data for accounting water budget of an aquifer of Middle Triassic limestones in the Susure plateau.

  19. Cenozoic basin development and its indication of plateau growth in the Xunhua-Guide district

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Xunhua, Guide and Tongren Basins are linked with the Laji Mountain and the northern West Qinling thrust belts in the Xunhua-Guide district. Basin depositional stratigraphy consists of the Oligocene Xining Group, the uppermost Oligocene-Pliocene Guide Group and the Lower Pleistocene. They are divided into three basin phases by unconformities. Basin phase 1 is composed of the Xining Group, and Basin phase 2 of the Zharang, Xiadongshan, Herjia and Ganjia Conglomerate Formations in the Guide Group, and Basin phase 3 of the Gonghe Formation and the Lower Pleistocene. Three basin phases all develop lacustrine deposits at their lower parts, and alluvial-braided channel plain depositional systems at upper parts, which constitute a coarsening-upward and progradational sequence. Basin deposition, paleocurrent and provenance analyses represent that large lacustrine basin across the Laji Mountain was developed and sourced from the West Qinling thrust belt during the stage of the Xining Group (Basin phase 1), and point-dispersed alluvial fan-braided channel plain deposition systems were developed beside the thrust and uplifted Laji Mountain and sourced from it, as thrusting migrated northwards during the stage of the Guide Group (Basin phase 2). Evolution of basin-mountain system in the study area significantly indicates the growth process of the distal Tibetan Plateau. The result shows that the Tibetan Plateau expanded to the northern West-Qinling at Oligocene (29―21.4 Ma) by means of northward folded-and-thrust thickening and uplifting and frontal foreland basin filling, and across the study area to North Qilian and Liupan Mountain at the Miocene-Pliocene (20.8―2.6 Ma) by means of two-sided basement-involved-thrust thickening and uplifting and broken foreland basin filling, and the distant end of Tibetan Plateau behaved as regional erosion and intermontane basin aggradational filling during the Pliocene and early Pleistocene (2.6―1.7 Ma).

  20. DNA damage during G2 phase does not affect cell cycle progression of the green alga Scenedesmus quadricauda.

    Directory of Open Access Journals (Sweden)

    Monika Hlavová

    Full Text Available DNA damage is a threat to genomic integrity in all living organisms. Plants and green algae are particularly susceptible to DNA damage especially that caused by UV light, due to their light dependency for photosynthesis. For survival of a plant, and other eukaryotic cells, it is essential for an organism to continuously check the integrity of its genetic material and, when damaged, to repair it immediately. Cells therefore utilize a DNA damage response pathway that is responsible for sensing, reacting to and repairing damaged DNA. We have studied the effect of 5-fluorodeoxyuridine, zeocin, caffeine and combinations of these on the cell cycle of the green alga Scenedesmus quadricauda. The cells delayed S phase and underwent a permanent G2 phase block if DNA metabolism was affected prior to S phase; the G2 phase block imposed by zeocin was partially abolished by caffeine. No cell cycle block was observed if the treatment with zeocin occurred in G2 phase and the cells divided normally. CDKA and CDKB kinases regulate mitosis in S. quadricauda; their kinase activities were inhibited by Wee1. CDKA, CDKB protein levels were stabilized in the presence of zeocin. In contrast, the protein level of Wee1 was unaffected by DNA perturbing treatments. Wee1 therefore does not appear to be involved in the DNA damage response in S. quadricauda. Our results imply a specific reaction to DNA damage in S. quadricauda, with no cell cycle arrest, after experiencing DNA damage during G2 phase.

  1. Property and heat storage performances of Glauber’s salt-based phase change materials for solar greenhouse in Qinghai-Tibet plateau%芒硝基相变材料性能及其在简易温室中升温效果试验

    Institute of Scientific and Technical Information of China (English)

    蒋自鹏; 铁生年

    2016-01-01

    to reduce their phase separation. In order to enhance its thermal conductivity, we chose graphitic material as the heat-removing agent. In this paper, we studied the properties of Glauber salt based phase change energy storage material and it’s performance of heat storage in winter in the Qinghai-Tibet Plateau region. Firstly, we prepared the Glauber salt based composite PCMs in laboratory, and then their thermal properties were measured by the differential scanning calorimetry (DSC). Samples were put in an alumina pan and heated from -10 to 40 ℃ at a rate of 1.0 ℃/min in purified nitrogen atmosphere (50 mL/min). The thermal cycling tests were carried out in an oven (Themo SCIENTIFIC HAAKE A 40) by heating and cooling the samples from 10 to 40 ℃ repeatedly. Thermal conductivities were determined by the transient plane source (TPS) method (Hot Disk, TPS 2200). The tested simple solar greenhouse was located in Xining City, Qinghai Province (101°44' E, 36°43' N). It was 3.5 m long and 2.7 m wide. The wall included 5 cm flexible foam (polyurethane) and 20 cm gypsum brick, as well as 0.1 cm iron sheet. The test period was from December 20th, 2015 to February 4th, 2016. The heat insulation sheet of the simple solar greenhouse was rolled up and down at 9:00 am and 5:00 pm on every sunny day, respectively. The temperatures of outdoor, and indoor air and gypsum wall, and solar irradiation were measured continuously at a time interval of 10 min. The data collected on a typical sunny day were used to study the heat-retaining properties in greenhouse with PCMs. When the temperature was higher than PCMs freezing and melting point, the PCMs released heat and froze. This paper explored the property about its undercooling, phase separation, thermal conductivity and phase change cycle. Two simple greenhouses were built, and the change of temperature was analyzed. Results showed that when adding the 4% borax (mass fraction), the supercooling of PCMs almost disappeared

  2. Solution-Phase Synthesis of SnSe Nanocrystals for Use in Solar Cells

    KAUST Repository

    Franzman, Matthew A.

    2010-03-31

    Nanocrystals of phase-pure tin(II) selenide (SnSe) were synthesized via a solution-phase route employing stoichiometric amounts of di-tert-butyl dlselenlde as a novel and facile selenium source. The direct band gap of the resulting nanocrystals (E8 = 1.71 eV) is significantly blue-shifted relative to the bulk value (E8 = 1.30 eV), a likely consequence of quantum confinement resulting from the relatively small average diameter of the nanocrystals (μD < 20 nm). Preliminary solar cell devices incorporating SnSe nanocrystals into a poly[2-methoxy5-(3\\',7\\'-d1methyloctyloxy)-1,4- phenylenev1nylene] matrix demonstrate a significant enhancement In quantum efficiency and short-circuit current density, suggesting that this earth-abundant material could be a valuable component In future photovoltaic devices. Copyright © 2010 American Chemical Society.

  3. Unreplicated DNA remaining from unperturbed S phases passes through mitosis for resolution in daughter cells.

    Science.gov (United States)

    Moreno, Alberto; Carrington, Jamie T; Albergante, Luca; Al Mamun, Mohammed; Haagensen, Emma J; Komseli, Eirini-Stavroula; Gorgoulis, Vassilis G; Newman, Timothy J; Blow, J Julian

    2016-09-27

    To prevent rereplication of genomic segments, the eukaryotic cell cycle is divided into two nonoverlapping phases. During late mitosis and G1 replication origins are "licensed" by loading MCM2-7 double hexamers and during S phase licensed replication origins activate to initiate bidirectional replication forks. Replication forks can stall irreversibly, and if two converging forks stall with no intervening licensed origin-a "double fork stall" (DFS)-replication cannot be completed by conventional means. We previously showed how the distribution of replication origins in yeasts promotes complete genome replication even in the presence of irreversible fork stalling. This analysis predicts that DFSs are rare in yeasts but highly likely in large mammalian genomes. Here we show that complementary strand synthesis in early mitosis, ultrafine anaphase bridges, and G1-specific p53-binding protein 1 (53BP1) nuclear bodies provide a mechanism for resolving unreplicated DNA at DFSs in human cells. When origin number was experimentally altered, the number of these structures closely agreed with theoretical predictions of DFSs. The 53BP1 is preferentially bound to larger replicons, where the probability of DFSs is higher. Loss of 53BP1 caused hypersensitivity to licensing inhibition when replication origins were removed. These results provide a striking convergence of experimental and theoretical evidence that unreplicated DNA can pass through mitosis for resolution in the following cell cycle.

  4. Unreplicated DNA remaining from unperturbed S phases passes through mitosis for resolution in daughter cells

    Science.gov (United States)

    Moreno, Alberto; Carrington, Jamie T.; Al Mamun, Mohammed; Haagensen, Emma J.; Komseli, Eirini-Stavroula; Gorgoulis, Vassilis G.; Newman, Timothy J.; Blow, J. Julian

    2016-01-01

    To prevent rereplication of genomic segments, the eukaryotic cell cycle is divided into two nonoverlapping phases. During late mitosis and G1 replication origins are “licensed” by loading MCM2-7 double hexamers and during S phase licensed replication origins activate to initiate bidirectional replication forks. Replication forks can stall irreversibly, and if two converging forks stall with no intervening licensed origin—a “double fork stall” (DFS)—replication cannot be completed by conventional means. We previously showed how the distribution of replication origins in yeasts promotes complete genome replication even in the presence of irreversible fork stalling. This analysis predicts that DFSs are rare in yeasts but highly likely in large mammalian genomes. Here we show that complementary strand synthesis in early mitosis, ultrafine anaphase bridges, and G1-specific p53-binding protein 1 (53BP1) nuclear bodies provide a mechanism for resolving unreplicated DNA at DFSs in human cells. When origin number was experimentally altered, the number of these structures closely agreed with theoretical predictions of DFSs. The 53BP1 is preferentially bound to larger replicons, where the probability of DFSs is higher. Loss of 53BP1 caused hypersensitivity to licensing inhibition when replication origins were removed. These results provide a striking convergence of experimental and theoretical evidence that unreplicated DNA can pass through mitosis for resolution in the following cell cycle. PMID:27516545

  5. Coordinated encoding between cell types in the retina: insights from the theory of phase transitions

    Science.gov (United States)

    Sharpee, Tatyana

    2015-03-01

    In this talk I will describe how the emergence of some types of neurons in the brain can be quantitatively described by the theory of transitions between different phases of matter. The two key parameters that control the separation of neurons into subclasses are the mean and standard deviation of noise levels among neurons in the population. The mean noise level plays the role of temperature in the classic theory of phase transitions, whereas the standard deviation is equivalent to pressure, in the case of liquid-gas transitions, or to magnetic field for magnetic transitions. Our results account for properties of two recently discovered types of salamander OFF retinal ganglion cells, as well as the absence of multiple types of ON cells. We further show that, across visual stimulus contrasts, retinal circuits continued to operate near the critical point whose quantitative characteristics matched those expected near a liquid-gas critical point and described by the nearest-neighbor Ising model in three dimensions. Because the retina needs to operate under changing stimulus conditions, the observed parameters of cell types corresponded to metastable states in the region between the spinodal line and the line describing maximally informative solutions. Such properties of neural circuits can maximize information transmission in a given environment while retaining the ability to quickly adapt to a new environment. NSF CAREER award 1254123 and NIH R01EY019493

  6. TNF phase III signalling in tolerant cells is tightly controlled by A20 and CYLD.

    Science.gov (United States)

    Bikker, Rolf; Christmann, Martin; Preuß, Katharina; Welz, Bastian; Friesenhagen, Judith; Dittrich-Breiholz, Oliver; Huber, René; Brand, Korbinian

    2017-09-01

    Following the acute phase of an inflammatory reaction, a strictly controlled resolution of inflammation is necessary. A dysregulation of this process leads to hyperinflammation, chronic inflammatory disease, or immune paralysis. Different mechanisms participate in the coordinated termination of the inflammatory process, e.g. the expression of antiinflammatory molecules and different forms of tolerance. To better understand the processes which mediate resolution of TNF-dependent inflammation and induce tolerance, it is necessary to characterize the signal transduction quality during TNF long-term (pre)incubation. Within a time frame from 12 to 48h, designated as phase III of the TNF response, we measured an ongoing, constitutive activation of TNFR1/NF-κB-dependent pathways in monocytic cells. Phase III signalling which was also named "constitutive signaling in TNF tolerant cells" induces the expression of low- and high-sensitive target genes including A20 which is differentially regulated by transcriptional and proteolytic events. A20 strictly controls TNF long-term constitutive signalling in an IκB kinase complex- and partially RIP-dependent manner supported by adjuvant ABIN1. In addition, CYLD proteins participate in the regulation of this late-phase signal transduction, whereas downstream molecules such as Bcl3 and p50 are not involved. A20 and CYLD are expressed with different mRNA kinetics resulting in a strong or only a modest increase in protein levels, respectively. The identification of mechanisms which contribute to the termination of inflammation will provide additional diagnostic and therapeutic aspects to specifically diagnose certain aspects of inflammation and specifically modulate them. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Measuring cell surface area and deformability of individual human red blood cells over blood storage using quantitative phase imaging

    Science.gov (United States)

    Park, Hyunjoo; Lee, Sangyun; Ji, Misuk; Kim, Kyoohyun; Son, Yonghak; Jang, Seongsoo; Park, Yongkeun

    2016-10-01

    The functionality and viability of stored human red blood cells (RBCs) is an important clinical issue in transfusions. To systematically investigate changes in stored whole blood, the hematological properties of individual RBCs were quantified in blood samples stored for various periods with and without a preservation solution called citrate phosphate dextrose adenine-1 (CPDA-1). With 3-D quantitative phase imaging techniques, the optical measurements for 3-D refractive index (RI) distributions and membrane fluctuations were done at the individual cell level. From the optical measurements, the morphological (volume, surface area and sphericity), biochemical (hemoglobin content and concentration), and mechanical parameters (dynamic membrane fluctuation) were simultaneously quantified to investigate the functionalities and progressive alterations of stored RBCs. Our results show that stored RBCs without CPDA-1 had a dramatic morphological transformation from discocytes to spherocytes within two weeks which was accompanied by significant decreases in cell deformability and cell surface area, and increases in sphericity. However, the stored RBCs with CPDA-1 maintained their morphology and deformability for up to 6 weeks.

  8. Dynamic contact mechanics on the tibial plateau of the human knee during activities of daily living.

    Science.gov (United States)

    Gilbert, Susannah; Chen, Tony; Hutchinson, Ian D; Choi, Dan; Voigt, Clifford; Warren, Russell F; Maher, Suzanne A

    2014-06-27

    Despite significant advances in scaffold design, manufacture, and development, it remains unclear what forces these scaffolds must withstand when implanted into the heavily loaded environment of the knee joint. The objective of this study was to fully quantify the dynamic contact mechanics across the tibial plateau of the human knee joint during gait and stair climbing. Our model consisted of a modified Stanmore knee simulator (to apply multi-directional dynamic forces), a two-camera motion capture system (to record joint kinematics), an electronic sensor (to record contact stresses on the tibial plateau), and a suite of post-processing algorithms. During gait, peak contact stresses on the medial plateau occurred in areas of cartilage-cartilage contact; while during stair climb, peak contact stresses were located in the posterior aspect of the plateau, under the meniscus. On the lateral plateau, during gait and in early stair-climb, peak contact stresses occurred under the meniscus, while in late stair-climb, peak contact stresses were experienced in the zone of cartilage-cartilage contact. At 45% of the gait cycle, and 20% and 48% of the stair-climb cycle, peak stresses were simultaneously experienced on both the medial and lateral compartment, suggesting that these phases of loading warrant particular consideration in any simulation intended to evaluate scaffold performance. Our study suggests that in order to design a scaffold capable of restoring 'normal' contact mechanics to the injured knees, the mechanics of the intended site of implantation should be taken into account in any pre-clinical testing regime.

  9. Aqueous two-phase partition applied to the isolation of plasma membranes and Golgi apparatus from cultured mammalian cells

    Science.gov (United States)

    Morre, D. M.; Morre, D. J.

    2000-01-01

    Partitioning in dextran-poly(ethylene)glycol (PEG) aqueous-aqueous phase systems represents a mature technology with many applications to separations of cells and to the preparation of membranes from mammalian cells. Most applications to membrane isolation and purification have focused on plasma membranes, plasma membrane domains and separation of right side-out and inside-out plasma membrane vesicles. The method exploits a combination of membrane properties, including charge and hydrophobicity. Purification is based upon differential distributions of the constituents in a sample between the two principal compartments of the two phases (upper and lower) and at the interface. The order of affinity of animal cell membranes for the upper phase is: endoplasmic reticulum Golgi apparatusGolgi apparatus from transformed mammalian cells that combines aqueous two-phase partition and centrifugation. Also described is a periodic NADH oxidase, a new enzyme marker for right side-out plasma membrane vesicles not requiring detergent disruptions for measurement of activity.

  10. Nucleolin down-regulation is involved in ADP-induced cell cycle arrest in S phase and cell apoptosis in vascular endothelial cells.

    Directory of Open Access Journals (Sweden)

    Wenmeng Wang

    Full Text Available High concentration of extracellular ADP has been reported to induce cell apoptosis, but the molecular mechanisms remain not fully elucidated. In this study, we found by serendipity that ADP treatment of human umbilical vein endothelial cells (HUVEC and human aortic endothelial cells (HAEC down-regulated the protein level of nucleolin in a dose- and time-dependent manner. ADP treatment did not decrease the transcript level of nucloelin, suggesting that ADP might induce nucleolin protein degradation. HUVEC and HAEC expressed ADP receptor P2Y13 receptor, but did not express P2Y1 or P2Y12 receptors. However, P2Y1, 12, 13 receptor antagonists MRS2179, PSB0739, MRS2211 did not inhibit ADP-induced down-regulation of nucleolin. Moreover, MRS2211 itself down-regulated nucleolin protein level. In addition, 2-MeSADP, an agonist for P2Y1, 12 and 13 receptors, did not down-regulate nucleolin protein. These results suggested that ADP-induced nucleolin down-regulation was not due to the activation of P2Y1, 12, or 13 receptors. We also found that ADP treatment induced cell cycle arrest in S phase, cell apoptosis and cell proliferation inhibition via nucleolin down-regulation. The over-expression of nucleolin by gene transfer partly reversed ADP-induced cell cycle arrest, cell apoptosis and cell proliferation inhibition. Furthermore, ADP sensitized HUVEC to cisplatin-induced cell death by the down-regulation of Bcl-2 expression. Taken together, we found, for the first time to our knowledge, a novel mechanism by which ADP regulates cell proliferation by induction of cell cycle arrest and cell apoptosis via targeting nucelolin.

  11. Gas phase recovery of hydrogen sulfide contaminated polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Kakati, Biraj Kumar; Kucernak, Anthony R. J.

    2014-04-01

    The effect of hydrogen sulfide (H2S) on the anode of a polymer electrolyte membrane fuel cell (PEMFC) and the gas phase recovery of the contaminated PEMFC using ozone (O3) were studied. Experiments were performed on fuel cell electrodes both in an aqueous electrolyte and within an operating fuel cell. The ex-situ analyses of a fresh electrode; a H2S contaminated electrode (23 μmolH2S cm-2); and the contaminated electrode cleaned with O3 shows that all sulfide can be removed within 900 s at room temperature. Online gas analysis of the recovery process confirms the recovery time required as around 720 s. Similarly, performance studies of an H2S contaminated PEMFC shows that complete rejuvenation occurs following 600-900 s O3 treatment at room temperature. The cleaning process involves both electrochemical oxidation (facilitated by the high equilibrium potential of the O3 reduction process) and direct chemical oxidation of the contaminant. The O3 cleaning process is more efficient than the external polarization of the single cell at 1.6 V. Application of O3 at room temperature limits the amount of carbon corrosion. Room temperature O3 treatment of poisoned fuel cell stacks may offer an efficient and quick remediation method to recover otherwise inoperable systems.

  12. Epitaxially grown polycrystalline silicon thin-film solar cells on solid-phase crystallised seed layers

    Science.gov (United States)

    Li, Wei; Varlamov, Sergey; Xue, Chaowei

    2014-09-01

    This paper presents the fabrication of poly-Si thin film solar cells on glass substrates using seed layer approach. The solid-phase crystallised P-doped seed layer is not only used as the crystalline template for the epitaxial growth but also as the emitter for the solar cell structure. This paper investigates two important factors, surface cleaning and intragrain defects elimination for the seed layer, which can greatly influence the epitaxial grown solar cell performance. Shorter incubation and crystallisation time is observed using a simplified RCA cleaning than the other two wet chemical cleaning methods, indicating a cleaner seed layer surface is achieved. Cross sectional transmission microscope images confirm a crystallographic transferal of information from the simplified RCA cleaned seed layer into the epi-layer. RTA for the SPC seed layer can effectively eliminate the intragrain defects in the seed layer and improve structural quality of both of the seed layer and the epi-layer. Consequently, epitaxial grown poly-Si solar cell on the RTA treated seed layer shows better solar cell efficiency, Voc and Jsc than the one on the seed layer without RTA treatment.

  13. Colorado Plateau magmatism and uplift by warming of heterogeneous lithosphere.

    Science.gov (United States)

    Roy, Mousumi; Jordan, Thomas H; Pederson, Joel

    2009-06-18

    The forces that drove rock uplift of the low-relief, high-elevation, tectonically stable Colorado Plateau are the subject of long-standing debate. While the adjacent Basin and Range province and Rio Grande rift province underwent Cenozoic shortening followed by extension, the plateau experienced approximately 2 km of rock uplift without significant internal deformation. Here we propose that warming of the thicker, more iron-depleted Colorado Plateau lithosphere over 35-40 Myr following mid-Cenozoic removal of the Farallon plate from beneath North America is the primary mechanism driving rock uplift. In our model, conductive re-equilibration not only explains the rock uplift of the plateau, but also provides a robust geodynamic interpretation of observed contrasts between the Colorado Plateau margins and the plateau interior. In particular, the model matches the encroachment of Cenozoic magmatism from the margins towards the plateau interior at rates of 3-6 km Myr(-1) and is consistent with lower seismic velocities and more negative Bouguer gravity at the margins than in the plateau interior. We suggest that warming of heterogeneous lithosphere is a powerful mechanism for driving epeirogenic rock uplift of the Colorado Plateau and may be of general importance in plate-interior settings.

  14. Cell cycle G2/M arrest through an S phase-dependent mechanism by HIV-1 viral protein R

    Directory of Open Access Journals (Sweden)

    Liang Dong

    2010-07-01

    Full Text Available Abstract Background Cell cycle G2 arrest induced by HIV-1 Vpr is thought to benefit viral proliferation by providing an optimized cellular environment for viral replication and by skipping host immune responses. Even though Vpr-induced G2 arrest has been studied extensively, how Vpr triggers G2 arrest remains elusive. Results To examine this initiation event, we measured the Vpr effect over a single cell cycle. We found that even though Vpr stops the cell cycle at the G2/M phase, but the initiation event actually occurs in the S phase of the cell cycle. Specifically, Vpr triggers activation of Chk1 through Ser345 phosphorylation in an S phase-dependent manner. The S phase-dependent requirement of Chk1-Ser345 phosphorylation by Vpr was confirmed by siRNA gene silencing and site-directed mutagenesis. Moreover, downregulation of DNA replication licensing factors Cdt1 by siRNA significantly reduced Vpr-induced Chk1-Ser345 phosphorylation and G2 arrest. Even though hydroxyurea (HU and ultraviolet light (UV also induce Chk1-Ser345 phosphorylation in S phase under the same conditions, neither HU nor UV-treated cells were able to pass through S phase, whereas vpr-expressing cells completed S phase and stopped at the G2/M boundary. Furthermore, unlike HU/UV, Vpr promotes Chk1- and proteasome-mediated protein degradations of Cdc25B/C for G2 induction; in contrast, Vpr had little or no effect on Cdc25A protein degradation normally mediated by HU/UV. Conclusions These data suggest that Vpr induces cell cycle G2 arrest through a unique molecular mechanism that regulates host cell cycle regulation in an S-phase dependent fashion.

  15. Well-posedness and asynchronous exponential growth of solutions of a two-phase cell division model

    Directory of Open Access Journals (Sweden)

    Meng Bai

    2010-04-01

    Full Text Available In this article we study a two-phase cell division model. The cells of the two different phases have different growth rates. We mainly consider the model of equal mitosis. By using the semigroup theory, we prove that this model is well-posed in suitable function spaces and its solutions have the property of asynchronous exponential growth as time approaches infinity. The corresponding model of asymmetric mitosis is also studied and similar results are obtained.

  16. Observational Facts of Sustained Departure Plateau Vortexes

    Institute of Scientific and Technical Information of China (English)

    YU Shuhua; GAO Wenliang; PENG Jun; XIAO Yuhua

    2014-01-01

    By using the twice-daily atmospheric observation data from 1998 to 2012, station rainfall data, Tropical Rainfall Measure Mission (TRMM) data, as well as the plateau vortex and shear line year book, charac-teristics of the sustained departure plateau vortexes (SDPVs) are analyzed. Some new useful observational facts and understanding are obtained about the SDPV activities. The following results are obtained. (1) The active period of SDPVs is from June to August, most in July, unlike that of the unsustained depar-ture plateau vortexes (UDPVs), which have same occurrence frequencies in the three summer months. (2) The SDPVs, generated mainly in the Qumalai neighborhood and situated in a sheared surrounding, move eastward or northeastward, while the UDPVs are mainly led by the upper-level trough, and move eastward or southeastward. (3) The SDPVs influence wide areas of China, even far to the Korean Peninsula, Japan, and Vietnam. (4) The SDPVs change their intensities and properties on the way to the east. Most of them become stronger and produce downpour or sustained regional rainstorms to the south of Yellow River. (5) The longer the SDPV sustains, the more baroclinity it has. (6) When an SDPV moves into the sea, its central pressure descends and rainfall increases in all probability. (7) An SDPV might spin over the bend of the Yellow River when there exists a tropical cyclone in the East China Sea. It could also move oppositely to a landed tropical low pressure originated from the sea to the east of Taiwan or from the South China Sea.

  17. Apoptosis is increased and cell proliferation is decreased in out-of-phase endometria from infertile and recurrent abortion patients

    Directory of Open Access Journals (Sweden)

    Irigoyen Marcela

    2010-10-01

    Full Text Available Abstract Background Various endometrial abnormalities have been associated with luteal phase deficiency: a significant dyssynchrony in the maturation of the glandular epithelium and the stroma and a prevalence of out-of-phase endometrial biopsy specimens. Out-of phase endometrium is a controversial disorder related to failed implantation, infertility and early pregnancy loss. Given that the regulation of the apoptotic process in endometrium of luteal phase deficiency is still unknown, the aim of this study was to evaluate cell proliferation, apoptosis and the levels of the main effector caspase, caspase-3 in the luteal in-phase and out-of-phase endometrium. Methods Thirty-seven endometrial samples from sterile or recurrent abortion patients were included in this study: 21 in-phase samples (controls and 16 samples with out-of-phase endometrium. Biopsy specimens of eutopic endometrium were obtained from all subjects during days 21-25 of the menstrual cycle. The endometrium with endometrial maturity of cycle day 25 or less at the time of menstruation was considered out-of phase. Endometrial tissues were fixed in 10% buffered formaldehyde. For apoptosis quantification, sections were processed for in situ immunohistochemical localization of nuclei exhibiting DNA fragmentation, by the terminal deoxynucleotidyl transferase (TdT-mediated dUTP digoxygenin nick-end labeling (TUNEL technique. Expressions of Proliferating Cell Nuclear Antigen (PCNA as a marker of cell proliferation, and of cleaved caspase-3 as a marker of apoptosis, were assessed by immunohistochemistry in the luteal in-phase and out-of-phase endometrium from infertile and recurrent abortion patients. Results Luteal out-of-phase endometrium had increased apoptosis levels compared to in-phase endometrium (p Conclusions this study represents the first report describing variations at the cell proliferation and cell death levels in the out-of-phase endometrium in comparison with in-phase

  18. Liquid-phase-deposited siloxane-based capping layers for silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Veith-Wolf, Boris [Institute for Solar Energy Research Hamelin (ISFH), Am Ohrberg 1, 31860 Emmerthal (Germany); Wang, Jianhui; Hannu-Kuure, Milja; Chen, Ning; Hadzic, Admir; Williams, Paul; Leivo, Jarkko; Karkkainen, Ari [Optitune International Pte. Ltd., 20 Maxwell Road, #05-08 Maxwell House, Singapore 069113 (Singapore); Schmidt, Jan [Institute for Solar Energy Research Hamelin (ISFH), Am Ohrberg 1, 31860 Emmerthal (Germany); Department of Solar Energy, Institute of Solid-State Physics, Leibniz University Hanover, Appelstrasse 2, 30167 Hanover (Germany)

    2015-02-02

    We apply non-vacuum processing to deposit dielectric capping layers on top of ultrathin atomic-layer-deposited aluminum oxide (AlO{sub x}) films, used for the rear surface passivation of high-efficiency crystalline silicon solar cells. We examine various siloxane-based liquid-phase-deposited (LPD) materials. Our optimized AlO{sub x}/LPD stacks show an excellent thermal and chemical stability against aluminum metal paste, as demonstrated by measured surface recombination velocities below 10 cm/s on 1.3 Ωcm p-type silicon wafers after firing in a belt-line furnace with screen-printed aluminum paste on top. Implementation of the optimized LPD layers into an industrial-type screen-printing solar cell process results in energy conversion efficiencies of up to 19.8% on p-type Czochralski silicon.

  19. Phase diagram determination up to 823K in minerals using Diamond Anvil Cell

    Science.gov (United States)

    Raju, S. V.; Knight, J.; Pawley, A. R.; Clark, S. M.

    2008-12-01

    : The ruby fluorescence technique is widely used for pressure measurement inside the diamond anvil cell. However, at higher temperatures estimation of pressure becomes complex due to the broadening of the fluorescence peaks. There are other fluorescence markers upon which temperature has a lower effect. For example Sm: SrB2O7. Here, we present a high pressure - high temperature calibration of Samarium doped SrB2O7. In order to minimize the error in determining the pressure, Strontium Borate along with Ruby were loaded in diamond anvil cell under hydrostatic conditions and fluorescence measurements were carried out upto temperatures of 823K under pressure. An equation routine is obtained to fit the peaks at various temperatures upto 823K under pressure. Using this data for pressure determination, phase diagram of Lawsonite was studied and the results are discussed.

  20. Calcium Alternans is Due to an Order-Disorder Phase Transition in Cardiac Cells

    Science.gov (United States)

    Alvarez-Lacalle, Enrique; Echebarria, Blas; Spalding, Jon; Shiferaw, Yohannes

    2015-03-01

    Electromechanical alternans is a beat-to-beat alternation in the strength of contraction of a cardiac cell, which can be caused by an instability of calcium cycling. Using a distributed model of subcellular calcium we show that alternans occurs via an order-disorder phase transition which exhibits critical slowing down and a diverging correlation length. We apply finite size scaling along with a mapping to a stochastic coupled map model, to show that this transition in two dimensions is characterized by critical exponents consistent with the Ising universality class. These findings highlight the important role of cooperativity in biological cells, and suggest novel approaches to investigate the onset of the alternans instability in the heart.

  1. A flow-through hydrothermal cell for in situ neutron diffraction studies of phase transformations

    Science.gov (United States)

    O'Neill, Brian; Tenailleau, Christophe; Nogthai, Yung; Studer, Andrew; Brugger, Joël; Pring, Allan

    2006-11-01

    A flow-through hydrothermal cell for the in situ neutron diffraction study of crystallisation and phase transitions has been developed. It can be used for kinetic studies on materials that exhibit structural transformations under hydrothermal conditions. It is specifically designed for use on the medium-resolution powder diffractometer (MRPD) at ANSTO, Lucas Heights, Sydney. But it is planned to adapt the design for the Polaris beamline at ISIS and the new high-intensity powder diffractometer (Wombat) at the new Australian reactor Opal. The cell will operate in a flow-through mode over the temperature range from 25-300 °C and up to pressures of 100 bar. The first results of a successful transformation of pentlandite (Fe,Ni) 9S 8 to violarite (Fe,Ni) 3S 4 under mild conditions (pH∼4) at 120 °C and 3 bar using in situ neutron diffraction measurements are presented.

  2. Total 3D imaging of phase objects using defocusing microscopy: application to red blood cells

    CERN Document Server

    Roma, P M S; Amaral, F T; Agero, U; Mesquita, O N

    2014-01-01

    We present Defocusing Microscopy (DM), a bright-field optical microscopy technique able to perform total 3D imaging of transparent objects. By total 3D imaging we mean the determination of the actual shapes of the upper and lower surfaces of a phase object. We propose a new methodology using DM and apply it to red blood cells subject to different osmolality conditions: hypotonic, isotonic and hypertonic solutions. For each situation the shape of the upper and lower cell surface-membranes (lipid bilayer/cytoskeleton) are completely recovered, displaying the deformation of RBCs surfaces due to adhesion on the glass-substrate. The axial resolution of our technique allowed us to image surface-membranes separated by distances as small as 300 nm. Finally, we determine volume, superficial area, sphericity index and RBCs refractive index for each osmotic condition.

  3. Relaxation rates of low-field gas-phase ^129Xe storage cells

    Science.gov (United States)

    Limes, Mark; Saam, Brian

    2010-10-01

    A study of longitudinal nuclear relaxation rates T1 of ^129Xe and Xe-N2 mixtures in a magnetic field of 3.8 mT is presented. In this regime, intrinsic spin relaxation is dominated by the intramolecular spin-rotation interaction due to persistent xenon dimers, a mechanism that can be quelled by introducing large amounts of N2 into the storage cell. Extrinsic spin relaxation is dominated by the wall-relaxation rate, which is the primary quantity of interest for the various low-field storage cells and coatings that we have tested. Previous group work has shown that extremely long gas-phase relaxation times T1 can be obtained, but only at large magnetic fields and low xenon densities. The current work is motivated by the practical benefits of retaining hyperpolarized ^129Xe for extended periods of time in a small magnetic field.

  4. Evidence of the thermo-electric Thomson effect and influence on the program conditions and cell optimization in phase-change memory cells

    NARCIS (Netherlands)

    Castro, D.T.; Goux, L.; Hurkx, G.A.M.; Attenborough, K.; Delhounge, R.; Lisoni, J.; Jedema, F.J.; Zandt, in 't M.A.A.; Wolters, R.A.M.; Gravesteijn, D.J.; Verheijen, M.; Kaiser, M.; Weemaes, R.G.R.

    2007-01-01

    We present physical and electrical evidence of the Thomson thermo-electric effect in line-type phase-change memory cells. This causes a shift of the molten zone during RESET programming towards the anode contact, and as a consequence the phase change material (PCM) design at the contact area has a s

  5. Exploring Feasibility for Application of Luminescent CdTe Quantum Dots Prepared in Aqueous Phase to Live Cell Imaging

    Institute of Scientific and Technical Information of China (English)

    Ji Fang WENG; Xing Tao SONG; Liang LI; Hui Feng QIAN; Ke Ying CHEN; Xue Ming XU; Cheng Xi CAO; Ji Cun REN

    2006-01-01

    This paper explored the feasibility for the application of luminescent CdTe quantum dots prepared in aqueous phase to live cell imaging. The highly luminescent CdTe quantum dots (QDs)were first prepared in aqueous phase, and then were covalently coupled to a plant lectin (UEA-1),as a fluorescent probe. After incubating with of human umbilical vein endothelial cells (HUVECs), the QD probe with UEA-1 was able to specifically bind the corresponding cell receptor. The good cell images were obtained in live cells using laser confocal scanning microscopy. We predict that QDs prepared in water phase will probably become an attractive alternative probe in cellular imaging and bio-labeling.

  6. Programmed cell death 2 protein induces gastric cancer cell growth arrest at the early S phase of the cell cycle and apoptosis in a p53-dependent manner.

    Science.gov (United States)

    Zhang, Jian; Wei, Wei; Jin, Hui-Cheng; Ying, Rong-Chao; Zhu, A-Kao; Zhang, Fang-Jie

    2015-01-01

    Programmed cell death 2 (PDCD2) is a highly conserved nuclear protein, and aberrant PDCD2 expression alters cell apoptosis. The present study aimed to investigate PDCD2 expression in gastric cancer. Tissue specimens from 34 gastric cancer patients were collected for analysis of PDCD2 expression using immunohistochemistry, western blotting and qRT-PCR. Gastric cancer cell lines (a p53-mutated MKN28 line and a wild-type p53 MKN45 line) were used to assess the effects of PDCD2 overexpression. p53-/- nude mice were used to investigate the effect of PDCD2 on ultraviolet B (UVB)-induced skin carcinogenesis. The data showed that PDCD2 expression was reduced in gastric cancer tissue specimens, and loss of PDCD2 expression was associated with the poor survival of patients. PDCD2 expression induced gastric cancer cell growth arrest at the early S phase of the cell cycle and apoptosis. The antitumor effects of PDCD2 expression were dependent on p53 expression in gastric cancer cells. Moreover, PDCD2 expression inhibited activity of the ATM/Chk1/2/p53 signaling pathway. In addition, PDCD2 expression suppressed UVB-induced skin carcinogenesis in p53+/+ nude mice, but not in p53-/- mice. The data from the present study demonstrated that loss of PDCD2 expression could contribute to gastric cancer development and progression and that PDCD2-induced gastric cancer cell growth arrest at the early S phase of the cell cycle and apoptosis are p53-dependent.

  7. Monitoring cell morphology during necrosis and apoptosis by quantitative phase imaging

    Science.gov (United States)

    Mugnano, Martina; Calabuig, Alejandro; Grilli, Simonetta; Miccio, Lisa; Ferraro, Pietro

    2015-05-01

    Cellular morphology changes and volume alterations play significant roles in many biological processes and they are mirrors of cell functions. In this paper, we propose the Digital Holographic microscope (DH) as a non-invasive imaging technique for a rapid and accurate extraction of morphological information related to cell death. In particular, we investigate the morphological variations that occur during necrosis and apoptosis. The study of necrosis is extremely important because it is often associated with unwarranted loss of cells in human pathologies such as ischemia, trauma, and some forms of neurodegeneration; therefore, a better elucidation in terms of cell morphological changes could pave the way for new treatments. Also, apoptosis is extremely important because it's involved in cancer, both in its formation and in medical treatments. Because the inability to initiate apoptosis enhances tumour formation, current cancer treatments target this pathway. Within this framework, we have developed a transmission off-axis DH apparatus integrated with a micro incubator for investigation of living cells in a temperature and CO2 controlled environment. We employ DH to analyse the necrosis cell death induced by laser light (wavelength 473 nm, light power 4 mW). We have chosen as cellular model NIH 3T3 mouse embryonic fibroblasts because their adhesive features such as morphological changes, and the time needed to adhere and spread have been well characterized in the literature. We have monitored cell volume changes and morphological alterations in real time in order to study the necrosis process accurately and quantitatively. Cell volume changes were evaluated from the measured phase changes of light transmitted through cells. Our digital holographic experiments showed that after exposure of cells to laser light for 90-120 min., they swell and then take on a balloon-like shape until the plasma membrane ruptures and finally the cell volume decreases. Furthermore, we

  8. Molecular identification of Taenia mustelae cysts in subterranean rodent plateau zokors (Eospalax baileyi).

    Science.gov (United States)

    Zhao, Fang; Ma, Jun-Ying; Cai, Hui-Xia; Su, Jian-Ping; Hou, Zhi-Bin; Zhang, Tong-Zuo; Lin, Gong-Hua

    2014-07-01

    Cestode larvae spend one phase of their two-phase life cycle in the viscera of rodents, but cases of cestodes infecting subterranean rodents have only been rarely observed. To experimentally gain some insight into this phenomenon, we captured approximately 300 plateau zokors (Eospalax baileyi), a typical subterranean rodent inhabiting the Qinghai-Tibet Plateau, and examined their livers for the presence of cysts. Totally, we collected five cysts, and using a mitochondrial gene (cox1) and two nuclear genes (pepck and pold) as genetic markers, we were able to analyze the taxonomy of the cysts. Both the maximum likelihood and Bayesian methods showed that the cysts share a monophyly with Taenia mustelae, while Kimura 2-parameter distances and number of different sites between our sequences and T. mustelae were far less than those found between the examined sequences and other Taeniidae species. These results, alongside supporting paraffin section histology, imply that the cysts found in plateau zokors can be regarded as larvae of T. mustelae, illustrating that zokors are a newly discovered intermediate host record of this parasite.

  9. Waves of Cdk1 Activity in S Phase Synchronize the Cell Cycle in Drosophila Embryos.

    Science.gov (United States)

    Deneke, Victoria E; Melbinger, Anna; Vergassola, Massimo; Di Talia, Stefano

    2016-08-22

    Embryos of most metazoans undergo rapid and synchronous cell cycles following fertilization. While diffusion is too slow for synchronization of mitosis across large spatial scales, waves of Cdk1 activity represent a possible process of synchronization. However, the mechanisms regulating Cdk1 waves during embryonic development remain poorly understood. Using biosensors of Cdk1 and Chk1 activities, we dissect the regulation of Cdk1 waves in the Drosophila syncytial blastoderm. We show that Cdk1 waves are not controlled by the mitotic switch but by a double-negative feedback between Cdk1 and Chk1. Using mathematical modeling and surgical ligations, we demonstrate a fundamental distinction between S phase Cdk1 waves, which propagate as active trigger waves in an excitable medium, and mitotic Cdk1 waves, which propagate as passive phase waves. Our findings show that in Drosophila embryos, Cdk1 positive feedback serves primarily to ensure the rapid onset of mitosis, while wave propagation is regulated by S phase events. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Novel Suicide Ligands of Tubulin Arrest Cancer Cells in S-Phase

    Directory of Open Access Journals (Sweden)

    Ashley Davis

    1999-12-01

    Full Text Available It is presently accepted that the mechanism of action for all anti-tumor tubulin ligands involves the perturbation of microtubule dynamics during the G2/M phase of cell division and subsequent entry into apoptosis 1]. In this report, we challenge the established dogma by describing a unique mechanism of action caused by a novel series of tubulin ligands, halogenated derivatives of acetamido benzoyl ethyl ester. We have developed a suicide ligand for tubulin, which covalently attaches to the target and shows potent cancericidal activity in tissue culture assays and in animal tumor models. These compounds target early S-phase at the G1/S transition rather than the G2/M phase and mitotic arrest. Bcl-2 phosphorylation, a marker of mitotic microtubule inhibition by other tubulin ligands was dramatically altered, phosphorylation was rapid and biphasic rather than a slow linear event. The halogenated ethyl ester series of derivatives thus constitute a unique set of tubulin ligands which induce a novel mechanism of apoptosis.

  11. Vascular endothelial cell membranes differentiate between stretch and shear stress through transitions in their lipid phases.

    Science.gov (United States)

    Yamamoto, Kimiko; Ando, Joji

    2015-10-01

    Vascular endothelial cells (ECs) respond to the hemodynamic forces stretch and shear stress by altering their morphology, functions, and gene expression. However, how they sense and differentiate between these two forces has remained unknown. Here we report that the plasma membrane itself differentiates between stretch and shear stress by undergoing transitions in its lipid phases. Uniaxial stretching and hypotonic swelling increased the lipid order of human pulmonary artery EC plasma membranes, thereby causing a transition from the liquid-disordered phase to the liquid-ordered phase in some areas, along with a decrease in membrane fluidity. In contrast, shear stress decreased the membrane lipid order and increased membrane fluidity. A similar increase in lipid order occurred when the artificial lipid bilayer membranes of giant unilamellar vesicles were stretched by hypotonic swelling, indicating that this is a physical phenomenon. The cholesterol content of EC plasma membranes significantly increased in response to stretch but clearly decreased in response to shear stress. Blocking these changes in the membrane lipid order by depleting membrane cholesterol with methyl-β-cyclodextrin or by adding cholesterol resulted in a marked inhibition of the EC response specific to stretch and shear stress, i.e., phosphorylation of PDGF receptors and phosphorylation of VEGF receptors, respectively. These findings indicate that EC plasma membranes differently respond to stretch and shear stress by changing their lipid order, fluidity, and cholesterol content in opposite directions and that these changes in membrane physical properties are involved in the mechanotransduction that activates membrane receptors specific to each force.

  12. Culture and Use of Mesenchymal Stromal Cells in Phase I and II Clinical Trials

    Directory of Open Access Journals (Sweden)

    Bourin Philippe

    2010-01-01

    Full Text Available Present in numerous tissues, mesenchymal stem cells/multipotent stromal cells (MSCs can differentiate into different cell types from a mesoderm origin. Their potential has been extended to pluripotency, by their possibility of differentiating into tissues and cells of nonmesodermic origin. Through the release of cytokines, growth factors and biologically active molecules, MSCs exert important paracrine effects during tissue repair and inflammation. Moreover, MSCs have immunosuppressive properties related to non-HLA restricted immunosuppressive capacities. All these features lead to an increasing range of possible applications of MSCs, from treating immunological diseases to tissue and organ repair, that should be tested in phase I and II clinical trials. The most widely used MSCs are cultured from bone marrow or adipose tissue. For clinical trial implementation, BM MSCs and ADSCs should be produced according to Good Manufacturing Practices. Safety remains the major concern and must be ensured during culture and validated with relevant controls. We describe some applications of MSCs in clinical trials.

  13. Culture and Use of Mesenchymal Stromal Cells in Phase I and II Clinical Trials

    Science.gov (United States)

    Philippe, Bourin; Luc, Sensebé; Valérie, Planat-Bénard; Jérôme, Roncalli; Alessandra, Bura-Rivière; Louis, Casteilla

    2010-01-01

    Present in numerous tissues, mesenchymal stem cells/multipotent stromal cells (MSCs) can differentiate into different cell types from a mesoderm origin. Their potential has been extended to pluripotency, by their possibility of differentiating into tissues and cells of nonmesodermic origin. Through the release of cytokines, growth factors and biologically active molecules, MSCs exert important paracrine effects during tissue repair and inflammation. Moreover, MSCs have immunosuppressive properties related to non-HLA restricted immunosuppressive capacities. All these features lead to an increasing range of possible applications of MSCs, from treating immunological diseases to tissue and organ repair, that should be tested in phase I and II clinical trials. The most widely used MSCs are cultured from bone marrow or adipose tissue. For clinical trial implementation, BM MSCs and ADSCs should be produced according to Good Manufacturing Practices. Safety remains the major concern and must be ensured during culture and validated with relevant controls. We describe some applications of MSCs in clinical trials. PMID:21052537

  14. In vivo quantification of SPIO nanoparticles for cell labeling based on MR phase gradient images.

    Science.gov (United States)

    Wang, Luning; Potter, William M; Zhao, Qun

    2015-01-01

    Along with the development of modern imaging technologies, contrast agents play increasingly important roles in both clinical applications and scientific research. Super-paramagnetic iron oxide (SPIO) nanoparticles, a negative contrast agent, have been extensively used in magnetic resonance imaging (MRI), such as in vivo labeling and tracking of cells. However, there still remain many challenges, such as in vivo quantification of SPIO nanoparticles. In this work, an MR phase gradient-based method was proposed to quantify the SPIO nanoparticles. As a calibration, a phantom experiment using known concentrations (10, 25, 50, 100, 150 and 250 µg/ml) of SPIO was first conducted to verify the proposed quantification method. In a following in vivo experiment, C6 glioma cells labeled with SPIO nanoparticles were implanted into flanks of four mice, which were scanned 1-3 days post-injection for in vivo quantification of SPIO concentration. The results showed that the concentration of SPIO nanoparticles could be determined in both phantom and in vivo experiments using the developed MR phase gradients approach.

  15. Increased production of megakaryocytes near purity from cord blood CD34+ cells using a short two-phase culture system.

    Science.gov (United States)

    Boyer, Lucie; Robert, Amélie; Proulx, Chantal; Pineault, Nicolas

    2008-03-20

    Expansion of hematopoietic progenitor cells (HPC) ex vivo remains an important focus in fundamental and clinical research. The aim of this study was to determine whether the implementation of such expansion phase in a two-phase culture strategy prior to the induction of megakaryocyte (Mk) differentiation would increase the yield of Mks produced in cultures. Toward this end, we first characterized the functional properties of five cytokine cocktails to be tested in the expansion phase on the growth and differentiation kinetics of CD34+-enriched cells, and on their capacity to expand clonogenic progenitors in cultures. Three of these cocktails were chosen based on their reported ability to induce HPC expansion ex vivo, while the other two represented new cytokine combinations. These analyses revealed that none of the cocktails tested could prevent the differentiation of CD34+ cells and the rapid expansion of lineage-positive cells. Hence, we sought to determine the optimum length of time for the expansion phase that would lead to the best final Mk yields. Despite greater expansion of CD34+ cells and overall cell growth with a longer expansion phase, the optimal length for the expansion phase that provided greater Mk yield at near maximal purity was found to be 5 days. Under such settings, two functionally divergent cocktails were found to significantly increase the final yield of Mks. Surprisingly, these cocktails were either deprived of thrombopoietin or of stem cell factor, two cytokines known to favor megakaryopoiesis and HPC expansion, respectively. Based on these results, a short resource-efficient two-phase culture protocol for the production of Mks near purity (>95%) from human CD34+ CB cells has been established.

  16. Network analysis of the transcriptional pattern of young and old cells of Escherichia coli during lag phase

    LENUS (Irish Health Repository)

    Pin, Carmen

    2009-11-16

    Abstract Background The aging process of bacteria in stationary phase is halted if cells are subcultured and enter lag phase and it is then followed by cellular division. Network science has been applied to analyse the transcriptional response, during lag phase, of bacterial cells starved previously in stationary phase for 1 day (young cells) and 16 days (old cells). Results A genome scale network was constructed for E. coli K-12 by connecting genes with operons, transcription and sigma factors, metabolic pathways and cell functional categories. Most of the transcriptional changes were detected immediately upon entering lag phase and were maintained throughout this period. The lag period was longer for older cells and the analysis of the transcriptome revealed different intracellular activity in young and old cells. The number of genes differentially expressed was smaller in old cells (186) than in young cells (467). Relatively, few genes (62) were up- or down-regulated in both cultures. Transcription of genes related to osmotolerance, acid resistance, oxidative stress and adaptation to other stresses was down-regulated in both young and old cells. Regarding carbohydrate metabolism, genes related to the citrate cycle were up-regulated in young cells while old cells up-regulated the Entner Doudoroff and gluconate pathways and down-regulated the pentose phosphate pathway. In both old and young cells, anaerobic respiration and fermentation pathways were down-regulated, but only young cells up-regulated aerobic respiration while there was no evidence of aerobic respiration in old cells. Numerous genes related to DNA maintenance and replication, translation, ribosomal biosynthesis and RNA processing as well as biosynthesis of the cell envelope and flagellum and several components of the chemotaxis signal transduction complex were up-regulated only in young cells. The genes for several transport proteins for iron compounds were up-regulated in both young and old cells

  17. Network analysis of the transcriptional pattern of young and old cells of Escherichia coli during lag phase

    Directory of Open Access Journals (Sweden)

    Hinton Jay CD

    2009-11-01

    Full Text Available Abstract Background The aging process of bacteria in stationary phase is halted if cells are subcultured and enter lag phase and it is then followed by cellular division. Network science has been applied to analyse the transcriptional response, during lag phase, of bacterial cells starved previously in stationary phase for 1 day (young cells and 16 days (old cells. Results A genome scale network was constructed for E. coli K-12 by connecting genes with operons, transcription and sigma factors, metabolic pathways and cell functional categories. Most of the transcriptional changes were detected immediately upon entering lag phase and were maintained throughout this period. The lag period was longer for older cells and the analysis of the transcriptome revealed different intracellular activity in young and old cells. The number of genes differentially expressed was smaller in old cells (186 than in young cells (467. Relatively, few genes (62 were up- or down-regulated in both cultures. Transcription of genes related to osmotolerance, acid resistance, oxidative stress and adaptation to other stresses was down-regulated in both young and old cells. Regarding carbohydrate metabolism, genes related to the citrate cycle were up-regulated in young cells while old cells up-regulated the Entner Doudoroff and gluconate pathways and down-regulated the pentose phosphate pathway. In both old and young cells, anaerobic respiration and fermentation pathways were down-regulated, but only young cells up-regulated aerobic respiration while there was no evidence of aerobic respiration in old cells. Numerous genes related to DNA maintenance and replication, translation, ribosomal biosynthesis and RNA processing as well as biosynthesis of the cell envelope and flagellum and several components of the chemotaxis signal transduction complex were up-regulated only in young cells. The genes for several transport proteins for iron compounds were up-regulated in both young

  18. Epitaxially grown polycrystalline silicon thin-film solar cells on solid-phase crystallised seed layers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wei, E-mail: weili.unsw@gmail.com; Varlamov, Sergey; Xue, Chaowei

    2014-09-30

    Highlights: • Crystallisation kinetic is used to analyse seed layer surface cleanliness. • Simplified RCA cleaning for the seed layer can shorten the epitaxy annealing duration. • RTA for the seed layer can improve the quality for both seed layer and epi-layer. • Epitaxial poly-Si solar cell performance is improved by RTA treated seed layer. - Abstract: This paper presents the fabrication of poly-Si thin film solar cells on glass substrates using seed layer approach. The solid-phase crystallised P-doped seed layer is not only used as the crystalline template for the epitaxial growth but also as the emitter for the solar cell structure. This paper investigates two important factors, surface cleaning and intragrain defects elimination for the seed layer, which can greatly influence the epitaxial grown solar cell performance. Shorter incubation and crystallisation time is observed using a simplified RCA cleaning than the other two wet chemical cleaning methods, indicating a cleaner seed layer surface is achieved. Cross sectional transmission microscope images confirm a crystallographic transferal of information from the simplified RCA cleaned seed layer into the epi-layer. RTA for the SPC seed layer can effectively eliminate the intragrain defects in the seed layer and improve structural quality of both of the seed layer and the epi-layer. Consequently, epitaxial grown poly-Si solar cell on the RTA treated seed layer shows better solar cell efficiency, V{sub oc} and J{sub sc} than the one on the seed layer without RTA treatment.

  19. Circulation and its seasonal variability in region around the Kerguelen Plateau

    Institute of Scientific and Technical Information of China (English)

    Shi Jiuxin(史久新); Le Kentang(乐肯堂); Byung Ho Choi

    2002-01-01

    A coupled ice-ocean isopycnal numerical model of the Southern Ocean is established to study the circulation and its seasonal variability in the region around the Kerguelen Plateau. An analysis of the simulated results shows significant stripe-like structure and non-zonal feature of the Antarctic Circumpolar Current (ACC) in this region. ACC begins to bifurcate and to turn its direction before meeting the plateau. The southernmost branch of ACC is near to the Antarctic coast and displays its strong interaction with the westward Antarctic Slope Current. The northern branch of ACC has a tendency of annual variations while the southern one varies in a semiannual cycle. The variation phases of both branches are coincident with that of the wind stress in this region.

  20. Simple and fast spectral domain algorithm for quantitative phase imaging of living cells with digital holographic microscopy.

    Science.gov (United States)

    Min, Junwei; Yao, Baoli; Ketelhut, Steffi; Engwer, Christian; Greve, Burkhard; Kemper, Björn

    2017-01-15

    We present a simple and fast phase aberration compensation method in digital holographic microscopy (DHM) for quantitative phase imaging of living cells. By analyzing the frequency spectrum of an off-axis hologram, phase aberrations can be compensated for automatically without fitting or pre-knowledge of the setup and/or the object. Simple and effective computation makes the method suitable for quantitative online monitoring with highly variable DHM systems. Results from automated quantitative phase imaging of living NIH-3T3 mouse fibroblasts demonstrate the effectiveness and the feasibility of the method.

  1. A rapid and robust assay for detection of S-phase cell cycle progression in plant cells and tissues by using ethynyl deoxyuridine

    Directory of Open Access Journals (Sweden)

    Horváth Gábor V

    2010-01-01

    Full Text Available Abstract Background Progress in plant cell cycle research is highly dependent on reliable methods for detection of cells replicating DNA. Frequency of S-phase cells (cells in DNA synthesis phase is a basic parameter in studies on the control of cell division cycle and the developmental events of plant cells. Here we extend the microscopy and flow cytometry applications of the recently developed EdU (5-ethynyl-2'-deoxyuridine-based S-phase assay to various plant species and tissues. We demonstrate that the presented protocols insure the improved preservation of cell and tissue structure and allow significant reduction in assay duration. In comparison with the frequently used detection of bromodeoxyuridine (BrdU and tritiated-thymidine incorporation, this new methodology offers several advantages as we discuss here. Results Applications of EdU-based S-phase assay in microscopy and flow cytometry are presented by using cultured cells of alfalfa, Arabidopsis, grape, maize, rice and tobacco. We present the advantages of EdU assay as compared to BrdU-based replication assay and demonstrate that EdU assay -which does not require plant cell wall digestion or DNA denaturation steps, offers reduced assay duration and better preservation of cellular, nuclear and chromosomal morphologies. We have also shown that fast and efficient EdU assay can also be an efficient tool for dual parameter flow cytometry analysis and for quantitative assessment of replication in thick root samples of rice. Conclusions In plant cell cycle studies, EdU-based S-phase detection offers a superior alternative to the existing S-phase assays. EdU method is reliable, versatile, fast, simple and non-radioactive and it can be readily applied to many different plant systems.

  2. Cytotoxicity of withasteroids: withametelin induces cell cycle arrest at G2/M phase and mitochondria-mediated apoptosis in non-small cell lung cancer A549 cells.

    Science.gov (United States)

    Rao, Poorna Chandra; Begum, Sajeli; Jahromi, Mohammad Ali Farboodniay; Jahromi, Zahra Hosseini; Sriram, Saketh; Sahai, Mahendra

    2016-09-01

    Considerable interest has been gained by withasteroids because of their structural uniqueness and wide spectrum of biological activities. However, limited systematic studies for proving their cytotoxic potential have so far been reported. Hence, an attempt was made to test the cytotoxicity of six withasteroids viz., withametelin (WM), withaphysalin D, withaphysalin E, 12-deoxywithastramonolide, Withaperuvin B, and physalolactone against A549, HT-29, and MDA-MB-231 cancer cell lines. Significant cytotoxic effect of WM against A549 cells (IC50 value of 6.0 μM), MDA-MB-231 cells (IC50 value of 7.6 μM), and HT-29 cells (IC50 value of 8.2 μM) was observed. Withaperuvin B and physalolactone were found to be effective against MDA-MB-231 cells. The significantly active WM arrested the A549 cells at G2/M phase and downregulated the expression of G2/M regulatory proteins such as cdc2, cyclin B1, and cdc25C. Apoptosis induced by WM in A549 cells was associated with the generation of ROS and depletion of MMP. Furthermore, WM treatment resulted in Bax upregulation, Bcl-2 downregulation, translocation of cytochrome c to mitochondria, activation of caspase-9 and -3, and PARP cleavage corroborating the apoptosis induction through intrinsic apoptotic pathway. Thus, WM possessing broader cytotoxic effect is a promising lead molecule which has the potential to be developed as a new therapeutic agent for NSCLC.

  3. Ethyl acetate extract of Squilla oratoria suppresses growth of HepG2 cells by inducing S phase arrest

    Directory of Open Access Journals (Sweden)

    Xiangwei Qi

    2013-08-01

    Full Text Available Objective: The oceans and seas are a rich source of organisms from which anti-cancer drugs can be isolated and developed. Marine organisms have been screened in our laboratory, and organic solvent extracts of Squilla oratoria (ESO have been shown to possess cytostatic effects on cancer cell lines of diverse origins. To explore the underlying mechanisms, the growth inhibition by ESO was investigated in the present study. Methods: Human hepatocellular carcinoma (HCC derived cells (HepG2 were used. The cells were challenged with ESO, cell cycle profile was assayed, and level of proliferating cell nuclear antigen (PCNA expression and that of cyclin D1 and cyclin A were evaluated with flow cytomtery. The in vivo antitumor effect of ESO was tested in nude mouse xenografts. PCNA expression was evaluated immunohistochemically in nude mouse xenograft tissues. Results: With the increase in dose of injected ESO, expression of PCNA by human HCC xenografts increased. ESO inhibited the growth of human HCC HepG2 cells both in vitro and in vivo. The effect was correlated with arrest of the cell cycle in S phase. Expression of PCNA, which is a cell-cycle regulator that promotes S phase entry, was elevated in both cell lines and xenografts whereas that of cyclins that promote M phase entry was down-regulated by exposure to ESO. Conclusion: Growth inhibition was explained by arrest of the cell cycle in S phase and down-regulation of molecules that promote cells to enter S phase. [J Exp Integr Med 2013; 3(4.000: 313-322

  4. Cell cycle phase dependent role of DNA polymerase beta in DNA repair and survival after ionizing radiation.

    NARCIS (Netherlands)

    Vermeulen, C.; Verwijs-Janssen, M.; Begg, A.C.; Vens, C.

    2008-01-01

    PURPOSE: The purpose of the present study was to determine the role of DNA polymerase beta in repair and response after ionizing radiation in different phases of the cell cycle. METHODS AND MATERIALS: Synchronized cells deficient and proficient in DNA polymerase beta were irradiated in different pha

  5. Effect of benzalkonium chloride on viability and energy metabolism in exponential- and stationary-growth-phase cells of Listeria monocytogenes

    NARCIS (Netherlands)

    Luppens, S.B.I.; Abee, T.; Oosterom, J.

    2001-01-01

    The difference in killing exponential- and stationary-phase cells of Listeria monocytogenes by benzalkonium chloride (BAC) was investigated by plate counting and linked to relevant bioenergetic parameters. At a low concentration of BAC (8 mg liter-1), a similar reduction in viable cell numbers was o

  6. Design of aqueous two-phase systems supporting animal cell growth: a first step toward extractive bioconversions.

    NARCIS (Netherlands)

    Zijlstra, G.M.; Gooijer, de C.D.; Pol, van der L.A.; Tramper, J.

    1996-01-01

    The design of aqueous two-phase systems (ATPSs) which support the long-term growth of animal cells is described in this paper. It was found that the increase in osmolality caused by the ATPS-forming polymers could be compensated by reducing the NaCl concentration of the culture medium. Cell growth

  7. Human T cell leukemia/lymphoma virus type I infection of a CD4+ proliferative/cytotoxic T cell clone progresses in at least two distinct phases based on changes in function and phenotype of the infected cells.

    Science.gov (United States)

    Yssel, H; de Waal Malefyt, R; Duc Dodon, M D; Blanchard, D; Gazzolo, L; de Vries, J E; Spits, H

    1989-04-01

    The effect of human T cell leukemia/lymphoma virus type I (HTLV-I) infection on the function and the phenotype of a human proliferating/cytotoxic T cell clone, specific for tetanus toxin, was investigated. During the period after infection, two distinct phases were observed, based on growth properties, phenotype, and functional activity of the infected cells. Phase I HTLV-I infected cells (0 to about 150 days after infection) proliferated in an IL-2-dependent way, but without the requirement for repetitive antigenic stimulation. No differences in expression of the CD2, CD3, CD4, Tp103, and CD28 Ag between these cells and the parental cells could be demonstrated, with the exception of the expression of IL-R p55 and HLA-DR Ag, which were constitutively expressed on the phase I cells. The phase I HTLV-I-infected cells, as well as the parental 827 cells reacted with a mAb specific for an epitope on the variable part of the TCR beta-chain, indicating that the TCR was not altered after HTLV-I infection. Like the parental clone, the phase I cells proliferated in response to tetanus toxin, but the tetanus toxin-specific response of the phase I cells did not require the presence of APC. Results of experiments, in which the levels of intracellular Ca2+ were measured, indicated that HTLV-I cells can acquire the capability to process Ag and present that to themselves. Phase I HTLV-I-infected T cells had lost their cytotoxic activity which was likely to be due to an effect on the lytic machinery rather than on Ag recognition by the TCR, inasmuch as it was found that phase I HTLV-I-infected T cells did no longer contain N-alpha-benzyloxy-L-lysine thiobenzylester-serine esterase activity. Furthermore, it was found that phase I HTLV-I-infected T cells had a diminished capacity to form conjugates with target cells. From a period of about 200 days after HTLV-I infection, phase II cells emerged that proliferated strongly in the absence of IL-2 and that had lost all functional

  8. Differential stimulation of hepatitis C virus RNA translation by microRNA-122 in different cell cycle phases.

    Science.gov (United States)

    Fehr, Carmen; Conrad, K Dominik; Niepmann, Michael

    2012-01-15

    Hepatitis C virus (HCV) replicates preferentially in the liver, and in most cases the HCV infection becomes chronic and often results in hepatocellular carcinoma. When the HCV plus-strand RNA genome has been delivered to the cytosol of the infected cell, its translation is directed by the Internal Ribosome Entry Site (IRES) in the 5'-untranslated region (5'-UTR) of the viral RNA. Thereby, IRES activity is modulated by several host factors. In particular, the liver-specific microRNA-122 (miR-122) interacts with two target sites in the HCV 5'-UTR and stimulates HCV translation, thereby most likely contributing to HCV liver tropism. Here we show that HCV IRES-dependent translation efficiency in the hepatoma cell line Huh7 is highest during the G₀ and G₁ phases of the cell cycle but significantly drops during the S phase and even more in the G₂/M phase. The superimposed stimulation of HCV translation by ectopic miR-122 works best during the G₀, G₁ and G₂/M phases but is lower during the S phase. However, the levels of Ago2 protein do not substantially change during cell cycle phases, indicating that other cellular factors involved in HCV translation stimulation by miR-122 may be differentially expressed in different cell cycle phases. Moreover, the levels of endogenously expressed miR-122 in Huh7 cells are lowest in the S phase, indicating that the predominant G₀/G₁ state of non-dividing hepatocytes in the liver facilitates high expression of the HCV genome and stimulation by miR-122, with yet unknown factors involved in the differential extent of stimulation by miR-122.

  9. The Manihiki Plateau, Hikurangi Plateau, Wishbone Scarp, and Osbourn Trough: A Review and Analysis

    Science.gov (United States)

    Henig, A.; Luyendyk, B. P.

    2007-12-01

    The extinct Osbourn Trough spreading system in the southwestern Pacific played a key role in separating the once joined Hikurangi and Manihiki Plateaus in Cretaceous time. Recent studies by Downey et al. [2007] and Taylor [20006] have provided new data and concepts on that history. Studies by Larson et al. [2002] describe Cretaceous histories adjacent and east of the Osbourn system and Eagles et al. [2004] describe a history for the southwest Pacific just after the Osbourn system became extinct. The lack of identifiable magnetic anomalies allows tectonic events during separation of the plateaus and spreading on the Osbourn Trough to occur between about 124.6 and 84 Ma (Chron 34). Satellite gravity maps of the region identify what are interpreted as Cretaceous fracture zone trends. Swath bathymetry data reveal at least four provinces of abyssal hill trends. What is known are the following: Minimum age of the Manihiki High Plateau at 123.4 Ma from DSDP Site 317, the age of seafloor, 115 Ma, from a dredge sample from the southern segment of the West Wishbone Scarp 300 km northeast of the Hikurangi Plateau, the east-west trend and extent of the extinct Osbourn spreading center at latitude 26° S, the trends (NNE-SSW to NE-SW) and extent of portions of the West Wishbone Scarp east of the Hikurangi Plateau, the N-S trend of the East Wishbone Scarp that appears to truncate the West Wishbone Scarp, the NNE- SSW trend and extent of the prominent Manihiki (Eastern) Scarp at the eastern boundary of the Manihiki High Plateau, the NW-SE trend and extent of the Rapuhia Scarp on the northwestern Hikurangi Plateau, and trends in abyssal hills; E-W near the Osbourn Trough and WNW-ESE closer to the plateaus. Differences in abyssal hill morphology suggest one or more changes in spreading rates. The Osbourn Trough began rifting apart a Large Igneous Province formed at 123.5 +/- 1.5 Ma, into the separate Ontong-Java, Manihiki, and Hikurangi Plateaus by 121 Ma. After an initial 6 Myr

  10. [Functional difference of malate-aspartate shuttle system in liver between plateau zokor (Myospalax baileyi) and plateau pika (Ochotona curzoniae)].

    Science.gov (United States)

    Zhu, Rui-Juan; Rao, Xin-Feng; Wei, Deng-Bang; Wang, Duo-Wei; Wei, Lian; Sun, Sheng-Zhen

    2012-04-25

    To explore the adaptive mechanisms of plateau zokor (Myospalax baileyi) to the enduring digging activity in the hypoxic environment and of plateau pika (Ochotona curzoniae) to the sprint running activity, the functional differences of malate-aspartate shuttle system (MA) in liver of plateau zokor and plateau pika were studied. The ratio of liver weight to body weight, the parameters of mitochondria in hepatocyte and the contents of lactic acid in serum were measured; the open reading frame of cytoplasmic malate dehydrogenase (MDH1), mitochondrial malate dehydrogenase (MDH2), and the partial sequence of aspartate glutamate carrier (AGC) and oxoglutarate malate carrier (OMC) genes were cloned and sequenced; MDH1, MDH2, AGC and OMC mRNA levels were determined by real-time PCR; the specific activities of MDH1 and MDH2 in liver of plateau zokor and plateau pika were measured using enzymatic methods. The results showed that, (1) the ratio of liver weight to body weight, the number and the specific surface of mitochondria in hepatocyte of plateau zokor were markedly higher than those of plateau pika (P 0.05); (3) mRNA level and enzymatic activity of MDH1 was significantly lower than those of MDH2 in the pika liver (P 0.05). These results indicate that the plateau zokor obtains ATP in the enduring digging activity by enhancing the function of MA, while plateau pika gets glycogen for their sprint running activity by increasing the process of gluconeogenesis. As a result, plateau pika converts the lactic acid quickly produced in their skeletal muscle by anaerobic glycolysis and reduces dependence on the oxygen.

  11. Plateau Waves of Intracranial Pressure and Multimodal Brain Monitoring.

    Science.gov (United States)

    Dias, Celeste; Maia, Isabel; Cerejo, Antonio; Smielewski, Peter; Paiva, José-Artur; Czosnyka, Marek

    2016-01-01

    The aim of this study was to describe multimodal brain monitoring characteristics during plateau waves of intracranial pressure (ICP) in patients with head injury, using ICM+ software for continuous recording. Plateau waves consist of an abrupt elevation of ICP above 40 mmHg for 5-20 min. This is a prospective observational study of patients with head injury who were admitted to a neurocritical care unit and who developed plateau waves. We analyzed 59 plateau waves that occurred in 8 of 18 patients (44 %). At the top of plateau waves arterial blood pressure remained almost constant, but cerebral perfusion pressure, cerebral blood flow, brain tissue oxygenation, and cerebral oximetry decreased. After plateau waves, patients with a previously better autoregulation status developed hyperemia, demonstrated by an increase in cerebral blood flow and brain oxygenation. Pressure and oxygen cerebrovascular reactivity indexes (pressure reactivity index and ORxshort) increased significantly during the plateau wave as a sign of disruption of autoregulation. Bedside multimodal brain monitoring is important to characterize increases in ICP and give differential diagnoses of plateau waves, as management of this phenomenon differs from that of regular ICP.

  12. Interpretation of Plateau in High-Harmonic Generation

    Institute of Scientific and Technical Information of China (English)

    程太旺; 李晓峰; 敖淑艳; 傅盘铭

    2003-01-01

    The plateau in high-harmonic generation is investigated in the frequency domain. Probability density of an electron in an electromagnetic field is obtained through analysing the quantized-field Volkov state. The plateau of high-harmonic generation reflects the spectral density of the electron at the location of nucleus after abovethreshold ionization.

  13. Mitofusin-2-mediated tethering of mitochondria and endoplasmic reticulum promotes cell cycle arrest of vascular smooth muscle cells in G0/G1 phase.

    Science.gov (United States)

    Li, Dan; Li, Xiaolan; Guan, Yang; Guo, Xiaomei

    2015-06-01

    Mitofusin-2 (Mfn-2) is a hyperplasia suppressor. Changes in Mfn-2 expression are thought to reflect mitochondrial remodeling during cell proliferation. However, it is unclear how the participation of Mfn-2 in mitochondrial remodeling prevents cellular proliferation. Here we show that arresting vascular smooth muscle cells (VSMCs) in the G0/G1 phase by serum starvation up-regulates Mfn-2 expression and causes mitochondria to assemble into a tubular network and to attach to the endoplasmic reticulum (ER). In the S phase, short rod-shaped mitochondrial structures that were dissociated from the ER were observed. Levels of glucose, ATP, l-amino acid, and NADP(+) did not vary throughout the cell cycle. However, NAD(+) level was lower and NADH level was higher in the G0/G1 phase than in the S phase. Mitochondrial membrane potential was lower in the S phase than in the G0/G1 phase. Infecting VSMCs with an adenovirus encoding full-length Mfn-2 increased NADH level and reduced NAD(+) level, while infecting the cells with an adenovirus that silences the p21(ras) signature motif produced opposite effects. These results suggest that Mfn-2 up-regulation causes mitochondrial fusion into tubular networks and attachment to the ER, which in turn halts proliferation of VSMCs. © The Author 2015. Published by ABBS Editorial Office in association with Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.

  14. Cell cycle arrest by prostaglandin A1 at the G1/S phase interface with up-regulation of oncogenes in S-49 cyc- cells

    Science.gov (United States)

    Hughes-Fulford, M.

    1994-01-01

    Our previous studies have implied that prostaglandins inhibit cell growth independent of cAMP. Recent reports, however, have suggested that prostaglandin arrest of the cell cycle may be mediated through protein kinase A. In this report, in order to eliminate the role of c-AMP in prostaglandin mediated cell cycle arrest, we use the -49 lymphoma variant (cyc-) cells that lack adenylate cyclase activity. We demonstrate that dimethyl prostaglandin A1 (dmPGA1) inhibits DNA synthesis and cell growth in cyc- cells. DNA synthesis is inhibited 42% by dmPGA1 (50 microM) despite the fact that this cell line lacks cellular components needed for cAMP generation. The ability to decrease DNA synthesis depends upon the specific prostaglandin structure with the most effective form possessing the alpha, beta unsaturated ketone ring. Dimethyl PGA1 is most effective in inhibiting DNA synthesis in cyc- cells, with prostaglandins PGE1 and PGB1 being less potent inhibitors of DNA synthesis. DmPGE2 caused a significant stimulation of DNA synthesis. S-49 cyc- variant cells exposed to (30-50 microns) dmPGA1, arrested in the G1 phase of the cell cycle within 24 h. This growth arrest was reversed when the prostaglandin was removed from the cultured cells; growth resumed within hours showing that this treatment is not toxic. The S-49 cyc- cells were chosen not only for their lack of adenylate cyclase activity, but also because their cell cycle has been extensively studied and time requirements for G1, S, G2, and M phases are known. Within hours after prostaglandin removal the cells resume active DNA synthesis, and cell number doubles within 15 h suggesting rapid entry into S-phase DNA synthesis from the G1 cell cycle block.(ABSTRACT TRUNCATED AT 250 WORDS).

  15. Diamond-anvil cell observations of a new methane hydrate phase in the 100-MPa pressure range

    Science.gov (United States)

    Chou, I.-Ming; Sharma, A.; Burruss, R.C.; Hemley, R.J.; Goncharov, A.F.; Stern, L.A.; Kirby, S.H.

    2001-01-01

    A new high-pressure phase of methane hydrate has been identified based on its high optical relief, distinct pressure-temperature phase relations, and Raman spectra. In-situ optical observations were made in a hydrothermal diamond-anvil cell at temperatures between -40?? and 60 ??C and at pressures up to 900 MPa. Two new invariant points were located at -8.7 ??C and 99 MPa for the assemblage consisting of the new phase, structure I methane hydrate, ice Ih, and water, and at 35.3 ??C and 137 MPa for the new phase-structure I methane hydrate-water-methane vapor. Existence of the new phase is critical for understanding the phase relations among the hydrates at low to moderate pressures, and may also have important implications for understanding the hydrogen bonding in H2O and the behavior of water in the planetary bodies, such as Europa, of the outer solar system.

  16. Parhelic-like circle from light scattering in Plateau borders

    Energy Technology Data Exchange (ETDEWEB)

    Tufaile, A., E-mail: tufaile@usp.br; Tufaile, A.P.B.

    2015-03-06

    We are reporting a new simple optical element to generate halos. We have observed interesting patterns of light scattering in Plateau borders in foams. In analogy to the atmospheric phenomena known as parhelic circle, sun dogs, and sun pillars, we have named the features of the patterns observed as parlaseric circle, laser dogs, and laser pillars. The triangular symmetry of the Plateau borders is analogous to the hexagonal symmetry of ice crystals which produce these atmospheric phenomena. Working with one Plateau border at a time, we have observed wave optics phenomena that are not perceived in the atmospheric phenomena, such as diffraction and interference. - Highlights: • We obtained halo formation from light scattering in a Plateau border using an experiment. • We explained halo formation using geometrical theory of diffraction. • An optical element based on a Plateau border is proposed. • We compared some aspects of the parhelic circle with the parlaseric circle.

  17. Two phase flow simulation in a channel of a polymer electrolyte membrane fuel cell using the lattice Boltzmann method

    OpenAIRE

    Ben Salah, Yasser; Tabe, Yutaka; Chikahisa, Takemi

    2012-01-01

    Water management in polymer electrolyte (PEM) fuel cells is important for fuel cell performance and durability. Numerical simulations using the lattice Boltzmann method (LBM) are developed to elucidate the dynamic behavior of condensed water and gas flows in a polymer electrolyte membrane (PEM) fuel cell gas channel. A scheme for two-phase flow with large density differences was applied to establish the optimum gas channel design for different gas channel heights, droplet positions, and gas c...

  18. Controversial results of therapy with mesenchymal stem cells in the acute phase of canine distemper disease.

    Science.gov (United States)

    Pinheiro, A O; Cardoso, M T; Vidane, A S; Casals, J B; Passarelli, D; Alencar, A L F; Sousa, R L M; Fantinato-Neto, P; Oliveira, V C; Lara, V M; Ambrósio, C E

    2016-05-23

    Distemper disease is an infectious disease reported in several species of domestic and wild carnivores. The high mortality rate of animals infected with canine distemper virus (CDV) treated with currently available therapies has driven the study of new efficacious treatments. Mesenchymal stem cell (MSC)-based therapy is a promising therapeutic option for many degenerative, hereditary, and inflammatory diseases. Therefore, the aim of this study was to characterize stem cells derived from the canine fetal olfactory epithelium and to assess the systemic response of animals infected with CDV to symptomatic therapy and treatment with MSCs. Eight domestic mongrel dogs (N = 8) were divided into two groups: support group (SG) (N = 5) and support group + cell therapy (SGCT) (N = 3), which were monitored over 15 days. Blood samples were collected on days 0, 6, 9, 12, and 15 to assess blood count and serum biochemistry (urea, creatinine, alanine transferase, alkaline phosphatase, gamma-glutamyl transferase, total protein, albumin, and globulin), and urine samples were obtained on days 0 and 15 for urinary evaluation (urine I). The results showed a high mortality rate (SG = 4 and SGCT = 2), providing inadequate data on the clinical course of CDV infection. MSC therapy resulted in no significant improvement when administered during the acute phase of canine distemper disease, and a prevalence of animals with high mortality rate was found in both groups due to the severity of symptoms.

  19. Phase 1 Study of Erlotinib Plus Radiation Therapy in Patients With Advanced Cutaneous Squamous Cell Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Heath, C. Hope; Deep, Nicholas L.; Nabell, Lisle; Carroll, William R.; Desmond, Renee; Clemons, Lisa; Spencer, Sharon; Magnuson, J. Scott [Division of Otolaryngology–Head and Neck Surgery, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama (United States); Rosenthal, Eben L., E-mail: oto@uab.edu [Division of Otolaryngology–Head and Neck Surgery, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama (United States)

    2013-04-01

    Purpose: To assess the toxicity profile of erlotinib therapy combined with postoperative adjuvant radiation therapy in patients with advanced cutaneous squamous cell carcinoma. Methods and Materials: This was a single-arm, prospective, phase 1 open-label study of erlotinib with radiation therapy to treat 15 patients with advanced cutaneous head-and-neck squamous cell carcinoma. Toxicity data were summarized, and survival was analyzed with the Kaplan-Meier method. Results: The majority of patients were male (87%) and presented with T4 disease (93%). The most common toxicity attributed to erlotinib was a grade 2-3 dermatologic reaction occurring in 100% of the patients, followed by mucositis (87%). Diarrhea occurred in 20% of the patients. The 2-year recurrence rate was 26.7%, and mean time to cancer recurrence was 10.5 months. Two-year overall survival was 65%, and disease-free survival was 60%. Conclusions: Erlotinib and radiation therapy had an acceptable toxicity profile in patients with advanced cutaneous squamous cell carcinoma. The disease-free survival in this cohort was comparable to that in historical controls.

  20. Rheumatoid arthritis and pigmented villonodular synovitis: comparative analysis of cell polyploidy, cell cycle phases and expression of macrophage and fibroblast markers in proliferating synovial cells.

    Science.gov (United States)

    Berger, I; Weckauf, H; Helmchen, B; Ehemann, V; Penzel, R; Fink, B; Bernd, L; Autschbach, F

    2005-05-01

    Rheumatoid arthritis (RA) and pigmented villonodular synovitis (PVNS) are aggressive diseases with progressive joint destruction. The present study aims to define cell cycle phases, polyploidy and the immunophenotype of proliferating synovial cells in both diseases. Synovial tissues from patients with proliferative-active RA, localized and diffuse PVNS were analysed by DNA flow cytometry, immunohistochemistry and double immunofluorescence with confocal laser scan microscopy. Expression of macrophage markers (CD68/CD163), fibroblast markers (h4Ph/CD55) and Ki67 antigen was examined. Synovial cells positive for either macrophage or fibroblast markers as well as double-labelled cells were found in both RA and PVNS. In RA, CD68/CD163+ synoviocytes were preferentially located in the vicinity of the synovial lining layer, while they were more randomly distributed in PVNS. Of cases with diffuse PVNS, 20% showed an aneuploid cell pattern. All samples of localized PVNS and RA were diploid. Proliferative activity was significantly higher in aneuploid PVNS. In spite of their histologically homogeneous appearance, proliferating synovial cells display a heterogeneous immunophenotype in both RA and PVNS, indicating functional properties of both macrophages and fibroblasts. Aneuploidy seems to be a special feature of diffuse PVNS.

  1. Nuclear translocation of Cyclin B1 marks the restriction point for terminal cell cycle exit in G2 phase.

    Science.gov (United States)

    Müllers, Erik; Silva Cascales, Helena; Jaiswal, Himjyot; Saurin, Adrian T; Lindqvist, Arne

    2014-01-01

    Upon DNA damage, cell cycle progression is temporally blocked to avoid propagation of mutations. While transformed cells largely maintain the competence to recover from a cell cycle arrest, untransformed cells past the G1/S transition lose mitotic inducers, and thus the ability to resume cell division. This permanent cell cycle exit depends on p21, p53, and APC/C(Cdh1). However, when and how permanent cell cycle exit occurs remains unclear. Here, we have investigated the cell cycle response to DNA damage in single cells that express Cyclin B1 fused to eYFP at the endogenous locus. We find that upon DNA damage Cyclin B1-eYFP continues to accumulate up to a threshold level, which is reached only in G2 phase. Above this threshold, a p21 and p53-dependent nuclear translocation required for APC/C(Cdh1)-mediated Cyclin B1-eYFP degradation is initiated. Thus, cell cycle exit is decoupled from activation of the DNA damage response in a manner that correlates to Cyclin B1 levels, suggesting that G2 activities directly feed into the decision for cell cycle exit. Once Cyclin B1-eYFP nuclear translocation occurs, checkpoint inhibition can no longer promote mitotic entry or re-expression of mitotic inducers, suggesting that nuclear translocation of Cyclin B1 marks the restriction point for permanent cell cycle exit in G2 phase.

  2. Quantitative phase imaging of biological cells and tissues using singleshot white light interference microscopy and phase subtraction method for extended range of measurement

    Science.gov (United States)

    Mehta, Dalip Singh; Sharma, Anuradha; Dubey, Vishesh; Singh, Veena; Ahmad, Azeem

    2016-03-01

    We present a single-shot white light interference microscopy for the quantitative phase imaging (QPI) of biological cells and tissues. A common path white light interference microscope is developed and colorful white light interferogram is recorded by three-chip color CCD camera. The recorded white light interferogram is decomposed into the red, green and blue color wavelength component interferograms and processed it to find out the RI for different color wavelengths. The decomposed interferograms are analyzed using local model fitting (LMF)" algorithm developed for reconstructing the phase map from single interferogram. LMF is slightly off-axis interferometric QPI method which is a single-shot method that employs only a single image, so it is fast and accurate. The present method is very useful for dynamic process where path-length changes at millisecond level. From the single interferogram a wavelength-dependent quantitative phase imaging of human red blood cells (RBCs) are reconstructed and refractive index is determined. The LMF algorithm is simple to implement and is efficient in computation. The results are compared with the conventional phase shifting interferometry and Hilbert transform techniques.

  3. Multicenter phase II study of matured dendritic cells pulsed with melanoma cell line lysates in patients with advanced melanoma

    Directory of Open Access Journals (Sweden)

    Hernandez Jackie

    2010-09-01

    Full Text Available Abstract Background Several single center studies have provided evidence of immune activation and antitumor activity of therapeutic vaccination with dendritic cells (DC in patients with metastatic melanoma. The efficacy of this approach in patients with favorable prognosis metastatic melanoma limited to the skin, subcutaneous tissues and lung (stages IIIc, M1a, M1b was tested in a multicenter two stage phase 2 study with centralized DC manufacturing. Methods The vaccine (IDD-3 consisted 8 doses of autologous monocyte-derived matured DC generated in serum-free medium with granulocyte macrophage colony stimulating factor (GM-CSF and interleukin-13 (IL-13, pulsed with lysates of three allogeneic melanoma cell lines, and matured with interferon gamma. The primary endpoint was antitumor activity. Results Among 33 patients who received IDD-3 there was one complete response (CR, two partial responses (PR, and six patients had stable disease (SD lasting more than eight weeks. The overall prospectively defined tumor growth control rate was 27% (90% confidence interval of 13-46%. IDD-3 administration had minimal toxicity and it resulted in a high frequency of immune activation to immunizing melanoma antigens as assessed by in vitro immune monitoring assays. Conclusions The administration of matured DC loaded with tumor lysates has significant immunogenicity and antitumor activity in patients with limited metastatic melanoma. Clinical trial registration NCT00107159.

  4. G0/G1 arrest and S phase inhibition of human cancer cell lines by inositol hexaphosphate (IP6).

    Science.gov (United States)

    El-Sherbiny, Y M; Cox, M C; Ismail, Z A; Shamsuddin, A M; Vucenik, I

    2001-01-01

    Inositol hexaphosphate (InsP6 or IP6) has shown a striking anti-cancer activity in both in vivo and in vitro models. In an attempt to elucidate the mechanism(s) underlying the anti-neoplastic potential of IP6, we investigated its effect on cell cycle progression of MCF-7 estrogen receptor (ER)-positive and MDA-MB 231 ER-negative human breast cancer cell lines and HT-29 human colon cancer cells. The anti-proliferative effect of IP6 was evaluated using dual-parameter flow cytometric measurements of DNA content, versus the incorporation of 5-bromo-2-deoxyuridine (BrdU) to determine cells actively synthesizing DNA. Combined analysis of the expression of cell cycle-related proteins, proliferation marker Ki-67 and proliferating cell nuclear antigen (PCNA) versus DNA content were used to determine the amount of proliferating cells in each phase, engaged in cell cycle transit. After 3 days of treatment with 5 mM IP6, S-phase, as estimated by BrdU uptake, was significantly decreased in all three cell lines (p = 0.002). MCF-7 and HT-29 cells accumulated in the G0/G1 range of DNA contents (p = 0.002 and p = 0.001, respectively). MDA MB-231 cells transiently accumulated in G0/G1 only after 2 days (p = 0.01). There was a significant decrease in the percentage of Ki-67 expression in IP6-treated cells, from 82.8+/-3.0% to 66.8+/-4.2% in MCF-7 (p = 0.007), from 93.4+/-4.6% to 71.7+/-3.3% in MDA-MB 231 (p = 0.004), and from 95.2+/-1.2% to 73.5+/-2.5% in HT-29 cells (p = 0.002) respectively. PCNA expression levels were also significantly decreased by IP6 in all three cell lines (MCF-7 p = 0.0007; MDA-MB 231 p = 0.0006; HT-29 p = 0.0001). These results show that IP6 controls the progression of cells through the cycle by decreasing S- phase and arresting cells in the G0/G1-phase of the cell cycle. A significant decrease in the expression of proliferation markers indicated that IP6 disengaged cells from actively cycling. Further investigations of cell cycle regulators may lead us to a

  5. Bartonella Species Detected in the Plateau Pikas (Ochotona curzoiae) from Qinghai Plateau in China.

    Science.gov (United States)

    Rao, Hua Xiang; Yu, Juan; Guo, Peng; Ma, Yong Cheng; Liu, Qi Yong; Jiao, Ming; Ma, Zhong Wen; Ge, Hua; Wang, Chun Xiang; Song, Xiu Ping; Shi, Yan; Li, Dong Mei

    2015-09-01

    Bartonella species can infect a variety of mammalian hosts and cause a broad spectrum of diseases in humans, but there have been no reports of Bartonella infection in Ochotonidae. This is the first study to detect Bartonella in plateau pikas in the Qinghai plateau, providing baseline data for the risk assessment of human Bartonella infection in this area. We obtained 15 Bartonella strains from 79 pikas in Binggou and Maixiu areas of Qinghai with a positive rate of 18.99%. Based on the phylogenetic analysis of the Bartonella citrate synthase (gltA) gene sequences, most strains were closely related to B. taylorii (3/15) and B. grahamii (12/15). The latter is a pathogenic strain in humans. Our results suggest that a corresponding prevention and control strategy should be taken into consideration in the Qinghai province.

  6. Extension of the Yellowstone plateau, eastern Snake River Plain, and Owyhee plateau

    Science.gov (United States)

    Rodgers, David W.; Hackett, William R.; Ore, H. Thomas

    1990-11-01

    Formation of the late Cenozoic volcanic province comprising the Owyhee plateau, eastern Snake River Plain, and Yellowstone plateau has been accompanied by east-northeast-directed crustal extension. A new vector of 45 mm/yr, N56°E for the migration of silicic volcanism across the volcanic province is calculated. If migration of volcanism reflects west-southwest continental drift over a mantle plume, a zone of crustal extension must separate the volcanic province from the more slowly moving North American craton. Space-time relations of basin fill in the adjacent Basin and Range province provide evidence for a zone of extension, about 125 km wide, coincident with and east of coeval silicic volcanism. Since 16 Ma, the zone of extension has migrated along with silicic volcanism, maintaining its position between the province and the unextended craton.

  7. Staphylococcus aureus-induced G2/M phase transition delay in host epithelial cells increases bacterial infective efficiency.

    Science.gov (United States)

    Alekseeva, Ludmila; Rault, Lucie; Almeida, Sintia; Legembre, Patrick; Edmond, Valérie; Azevedo, Vasco; Miyoshi, Anderson; Even, Sergine; Taieb, Frédéric; Arlot-Bonnemains, Yannick; Le Loir, Yves; Berkova, Nadia

    2013-01-01

    Staphylococcus aureus is a highly versatile, opportunistic pathogen and the etiological agent of a wide range of infections in humans and warm-blooded animals. The epithelial surface is its principal site of colonization and infection. In this work, we investigated the cytopathic effect of S. aureus strains from human and animal origins and their ability to affect the host cell cycle in human HeLa and bovine MAC-T epithelial cell lines. S. aureus invasion slowed down cell proliferation and induced a cytopathic effect, resulting in the enlargement of host cells. A dramatic decrease in the number of mitotic cells was observed in the infected cultures. Flow cytometry analysis revealed an S. aureus-induced delay in the G2/M phase transition in synchronous HeLa cells. This delay required the presence of live S. aureus since the addition of the heat-killed bacteria did not alter the cell cycle. The results of Western blot experiments showed that the G2/M transition delay was associated with the accumulation of inactive cyclin-dependent kinase Cdk1, a key inducer of mitosis entry, and with the accumulation of unphosphorylated histone H3, which was correlated with a reduction of the mitotic cell number. Analysis of S. aureus proliferation in asynchronous, G1- and G2-phase-enriched HeLa cells showed that the G2 phase was preferential for bacterial infective efficiency, suggesting that the G2 phase delay may be used by S. aureus for propagation within the host. Taken together, our results divulge the potential of S. aureus in the subversion of key cellular processes such as cell cycle progression, and shed light on the biological significance of S. aureus-induced host cell cycle alteration.

  8. Staphylococcus aureus-induced G2/M phase transition delay in host epithelial cells increases bacterial infective efficiency.

    Directory of Open Access Journals (Sweden)

    Ludmila Alekseeva

    Full Text Available Staphylococcus aureus is a highly versatile, opportunistic pathogen and the etiological agent of a wide range of infections in humans and warm-blooded animals. The epithelial surface is its principal site of colonization and infection. In this work, we investigated the cytopathic effect of S. aureus strains from human and animal origins and their ability to affect the host cell cycle in human HeLa and bovine MAC-T epithelial cell lines. S. aureus invasion slowed down cell proliferation and induced a cytopathic effect, resulting in the enlargement of host cells. A dramatic decrease in the number of mitotic cells was observed in the infected cultures. Flow cytometry analysis revealed an S. aureus-induced delay in the G2/M phase transition in synchronous HeLa cells. This delay required the presence of live S. aureus since the addition of the heat-killed bacteria did not alter the cell cycle. The results of Western blot experiments showed that the G2/M transition delay was associated with the accumulation of inactive cyclin-dependent kinase Cdk1, a key inducer of mitosis entry, and with the accumulation of unphosphorylated histone H3, which was correlated with a reduction of the mitotic cell number. Analysis of S. aureus proliferation in asynchronous, G1- and G2-phase-enriched HeLa cells showed that the G2 phase was preferential for bacterial infective efficiency, suggesting that the G2 phase delay may be used by S. aureus for propagation within the host. Taken together, our results divulge the potential of S. aureus in the subversion of key cellular processes such as cell cycle progression, and shed light on the biological significance of S. aureus-induced host cell cycle alteration.

  9. Phase-based x-ray scattering—A possible method to detect cancer cells in a very early stage

    Energy Technology Data Exchange (ETDEWEB)

    Feye-Treimer, U., E-mail: feye-treimer@helmholtz-berlin.de; Treimer, W. [Department of Mathematics, Physics and Chemistry, University of Applied Sciences, D-13353 Berlin, Germany and Joint Department G-GTOMO, Helmholtz Zentrum fuer Materialien und Energie Berlin, D-14109 Berlin (Germany)

    2014-05-15

    Purpose: This theoretical work contains a detailed investigation of the potential and sensitivity of phase-based x-ray scattering for cancer detection in biopsies if cancer is in a very early stage of development. Methods: Cancer cells in their early stage of development differ from healthy ones mainly due to their faster growing cell nuclei and the enlargement of their densities. This growth is accompanied by an altered nucleus–plasma relation for the benefit of the cell nuclei, that changes the physical properties especially the index of refraction of the cell and the one of the cell nuclei. Interaction of radiation with matter is known to be highly sensitive to small changes of the index of refraction of matter; therefore a detection of such changes of volume and density of cell nuclei by means of high angular resolved phase-based scattering of x rays might provide a technique to distinguish malignant cells from healthy ones ifthe cell–cell nucleus system is considered as a coherent phase shifting object. Then one can observe from a thin biopsy which represents a monolayer of cells (no multiple scattering) that phase-based x-ray scattering curves from healthy cells differ from those of cancer cells in their early stage of development. Results: Detailed calculations of x-ray scattering patterns from healthy and cancer cell nuclei yield graphs and numbers with which one can distinguish healthy cells from cancer ones, taking into account that both kinds of cells occur in a tissue within a range of size and density. One important result is the role and the influence of the (lateral) coherence width of the radiation on the scattering curves and the sensitivity of phase-based scattering for cancer detection. A major result is that a larger coherence width yields a larger sensitivity for cancer detection. Further import results are calculated limits for critical sizes and densities of cell nuclei in order to attribute the investigated tissue to be healthy or

  10. Late phase cell cycle proteins in Alzheimer’s disease: a possible target for therapy?

    KAUST Repository

    Bajic, Vladan

    2017-02-22

    Alzheimer’s disease (AD) is represented by neuronal loss and this loss is correlated to a constant state of neuronal instability induced by intrinsic and extrinsic factors. In this paper data is presented regarding the possible roles of late phase cell cycle proteins in normal and affected neurons with the goal that understanding the mechanisms involved in the regulation of these proteins may represent a novel strategy for AD treatment. The results demonstrate a relative differential pattern of expression of certain proteins (APC/C, Mad1 and Mad2, Bub R1, Bub1, CDK 11, cohesin subunit Rad 21 and astrin) in the AD brain versus age matched controls, and it is suggested that targeting these proteins might translate into potential treatments for AD. Although the data presented here is of some interest, the ability to translate such information into clinical applications is often a challenge.

  11. Delayed Phase Nasal Metastasis of Renal Cell Carcinoma as a Rare Epistaxis Cause

    Directory of Open Access Journals (Sweden)

    Kerem Ozturk

    2014-03-01

    Full Text Available    Malign tumors of sinonasal area composes %1 of malignant tumors in adults and %3 of head and neck malignities. Metastasis to this area is rare but malignities that metastatic to head and neck and below down clavicula, renal cell carcinoma (RCC is the third after lung and breast cancer . As the most frequent malignancy of kidney, RCC is generally seen in male over 40 year old and forms %3 of malign tumors in adults and in RCC cases %8 of disease arises by the metastasis to head and neck which is accepted as a bad prognostic factor. In this case report, a 81 year old male patient is presented with literature datas who is underwent nephrectomy 8 years ago for RCC and referred with recurrent epistaxis and delayed phase nasal RCC metastasis.

  12. Deep structure of the Iceland plateau

    Energy Technology Data Exchange (ETDEWEB)

    Evans, J.R.; Sacks, I.S.

    1979-11-10

    The topography of the sea floor between Iceland and Jan Mayen Island is flat and elevated in relation to most ocean basins. Marine geophysical observations in the area have shown that it was formed by sea floor spreading but have not revealed details of structures more than a few hundred meters beneath the sea floor. We have examined the dispersion of seismic surface waves across the Iceland Plateau and have modeled structures to depths of up to 100 km. We find that the thickness of the crustal component of the lithosphere is much greater than that of normal oceanic structures, perhaps exceeding 20 km. We suggest that the elevation of the region is due to isostatic compensation for this excess of low-density crustal material. The total lithospheric thickness is about 50 km throughout the region, indicating that the lithosphere thickens with age at a rate similar to that found in other young oceans.

  13. Plateau inflation in SUGRA-MSSM

    Science.gov (United States)

    Chakravarty, Girish Kumar; Gupta, Gaveshna; Lambiase, Gaetano; Mohanty, Subhendra

    2016-09-01

    We explored a Higgs inflationary scenario in the SUGRA embedding of the MSSM in Einstein frame where the inflaton is contained in the SU (2) Higgs doublet. We include all higher order non-renormalizable terms to the MSSM superpotential and an appropriate Kähler potential which can provide slow-roll inflaton potential in the D-flat direction. In this model, a plateau-like inflation potential can be obtained if the imaginary part of the neutral Higgs acts as the inflaton. The inflationary predictions of this model are consistent with the latest CMB observations. The model represents a successful Higgs inflation scenario in the context of Supergravity and it is compatible with Minimal Supersymmetric extension of the Standard Model.

  14. Plateau inflation in SUGRA-MSSM

    Directory of Open Access Journals (Sweden)

    Girish Kumar Chakravarty

    2016-09-01

    Full Text Available We explored a Higgs inflationary scenario in the SUGRA embedding of the MSSM in Einstein frame where the inflaton is contained in the SU(2 Higgs doublet. We include all higher order non-renormalizable terms to the MSSM superpotential and an appropriate Kähler potential which can provide slow-roll inflaton potential in the D-flat direction. In this model, a plateau-like inflation potential can be obtained if the imaginary part of the neutral Higgs acts as the inflaton. The inflationary predictions of this model are consistent with the latest CMB observations. The model represents a successful Higgs inflation scenario in the context of Supergravity and it is compatible with Minimal Supersymmetric extension of the Standard Model.

  15. Plateau potentials in sacrocaudal motoneurons of chronic spinal rats, recorded in vitro.

    Science.gov (United States)

    Bennett, D J; Li, Y; Siu, M

    2001-10-01

    Intracellular recordings were made from sacrocaudal tail motoneurons of acute and chronic spinal rats to examine whether plateau potentials contribute to spasticity associated with chronic injury. The spinal cord was transected at the S2 level, causing, over time, exaggerated long-lasting reflexes (hyperreflexia) associated with a general spasticity syndrome in the tail muscles of chronic spinal rats (1-5 mo postinjury). The whole sacrocaudal spinal cord of chronic or acute spinal rats was removed and maintained in vitro in normal artificial cerebral spinal fluid (ACSF). Hyperreflexia in chronic spinal rats was verified by recording the long-lasting ventral root responses to dorsal root stimulation in vitro. The intrinsic properties of sacrocaudal motoneurons were studied using intracellular injections of slow triangular current ramps or graded current pulses. In chronic spinal rats, the current injection triggered sustained firing and an associated sustained depolarization (plateau potential; 34/35 cells; mean, 5.5 mV; duration >5 s; normal ACSF). The threshold for plateau initiation was low and usually corresponded to an acceleration in the membrane potential just before recruitment. After recruitment and plateau activation, the firing rate changed linearly with current during the slow ramps [63% of cells had a linear frequency-current (F-I) relation] despite the presence of the plateau. The persistent inward current (I(PIC)) producing the plateau and sustained firing was estimated to be on average 0.8 nA as determined by the reduction in injected current needed to stop the sustained firing [DeltaI = -0.8 +/- 0.6 (SD) nA], compared with the current needed to start firing (I = 1.7 +/- 1.5 nA; 47% reduction). In motoneurons of acute spinal rats, plateaus were rarely seen (3/22), although they could be made to occur with bath application of serotonin. In motoneurons of chronic spinal rats there were no significant changes in the mean passive input resistance

  16. Hypoxia induces a phase transition within a kinase signaling network in cancer cells.

    Science.gov (United States)

    Wei, Wei; Shi, Qihui; Remacle, Francoise; Qin, Lidong; Shackelford, David B; Shin, Young Shik; Mischel, Paul S; Levine, R D; Heath, James R

    2013-04-09

    Hypoxia is a near-universal feature of cancer, promoting glycolysis, cellular proliferation, and angiogenesis. The molecular mechanisms of hypoxic signaling have been intensively studied, but the impact of changes in oxygen partial pressure (pO2) on the state of signaling networks is less clear. In a glioblastoma multiforme (GBM) cancer cell model, we examined the response of signaling networks to targeted pathway inhibition between 21% and 1% pO2. We used a microchip technology that facilitates quantification of a panel of functional proteins from statistical numbers of single cells. We find that near 1.5% pO2, the signaling network associated with mammalian target of rapamycin (mTOR) complex 1 (mTORC1)--a critical component of hypoxic signaling and a compelling cancer drug target--is deregulated in a manner such that it will be unresponsive to mTOR kinase inhibitors near 1.5% pO2, but will respond at higher or lower pO2 values. These predictions were validated through experiments on bulk GBM cell line cultures and on neurosphere cultures of a human-origin GBM xenograft tumor. We attempt to understand this behavior through the use of a quantitative version of Le Chatelier's principle, as well as through a steady-state kinetic model of protein interactions, both of which indicate that hypoxia can influence mTORC1 signaling as a switch. The Le Chatelier approach also indicates that this switch may be thought of as a type of phase transition. Our analysis indicates that certain biologically complex cell behaviors may be understood using fundamental, thermodynamics-motivated principles.

  17. Liquid phase crystallized silicon on glass: Technology, material quality and back contacted heterojunction solar cells

    Science.gov (United States)

    Haschke, Jan; Amkreutz, Daniel; Rech, Bernd

    2016-04-01

    Liquid phase crystallization has emerged as a novel approach to grow large grained polycrystalline silicon films on glass with high electronic quality. In recent years a lot of effort was conducted by different groups to determine and optimize suitable interlayer materials, enhance the crystallographic quality or to improve post crystallization treatments. In this paper, we give an overview on liquid phase crystallization and describe the necessary process steps and discuss their influence on the absorber properties. Available line sources are compared and different interlayer configurations are presented. Furthermore, we present one-dimensional numerical simulations of a rear junction device, considering silicon absorber thicknesses between 1 and 500 µm. We vary the front surface recombination velocity as well as doping density and minority carrier lifetime in the absorber. The simulations suggest that a higher absorber doping density is beneficial for layer thicknesses below 20 µm or when the minority carrier lifetime is short. Finally, we discuss possible routes for device optimization and propose a hybride cell structure to circumvent current limitations in device design.

  18. A complete two-phase model of a porous cathode of a PEM fuel cell

    Science.gov (United States)

    Hwang, J. J.

    This paper has developed a complete two-phase model of a proton exchange membrane (PEM) fuel cell by considering fluid flow, heat transfer and current simultaneously. In fluid flow, two momentum equations governing separately the gaseous-mixture velocity (u g) and the liquid-water velocity (u w) illustrate the behaviors of the two-phase flow in a porous electrode. Correlations for the capillary pressure and the saturation level connect the above two-fluid transports. In heat transfer, a local thermal non-equilibrium (LTNE) model accounting for intrinsic heat transfer between the reactant fluids and the solid matrices depicts the interactions between the reactant-fluid temperature (T f) and the solid-matrix temperature (T s). The irreversibility heating due to electrochemical reactions, Joule heating arising from Ohmic resistance, and latent heat of water condensation/evaporation are considered in the present non-isothermal model. In current, Ohm's law is applied to yield the conservations in ionic current (i m) and electronic current (i s) in the catalyst layer. The Butler-Volmer correlation describes the relation of the potential difference (overpotential) and the transfer current between the electrolyte (such as Nafion™) and the catalyst (such as Pt/C).

  19. Evidence for thermally assisted threshold switching behavior in nanoscale phase-change memory cells

    Energy Technology Data Exchange (ETDEWEB)

    Le Gallo, Manuel; Athmanathan, Aravinthan; Krebs, Daniel; Sebastian, Abu [IBM Research-Zurich, 8803 Rüschlikon (Switzerland)

    2016-01-14

    In spite of decades of research, the details of electrical transport in phase-change materials are still debated. In particular, the so-called threshold switching phenomenon that allows the current density to increase steeply when a sufficiently high voltage is applied is still not well understood, even though there is wide consensus that threshold switching is solely of electronic origin. However, the high thermal efficiency and fast thermal dynamics associated with nanoscale phase-change memory (PCM) devices motivate us to reassess a thermally assisted threshold switching mechanism, at least in these devices. The time/temperature dependence of the threshold switching voltage and current in doped Ge{sub 2}Sb{sub 2}Te{sub 5} nanoscale PCM cells was measured over 6 decades in time at temperatures ranging from 40 °C to 160 °C. We observe a nearly constant threshold switching power across this wide range of operating conditions. We also measured the transient dynamics associated with threshold switching as a function of the applied voltage. By using a field- and temperature-dependent description of the electrical transport combined with a thermal feedback, quantitative agreement with experimental data of the threshold switching dynamics was obtained using realistic physical parameters.

  20. Interface control in organic heterojunction photovoltaic cells by phase separation processes

    Science.gov (United States)

    Heier, Jakob; Castro, Fernando A.; Nüesch, Frank; Hany, Roland

    2007-09-01

    Significant progress is being made in the photovoltaic energy conversion using organic semiconducting materials. One of the focuses of attention is the nanoscale morphology of the donor-acceptor mixture, to ensure efficient charge generation and loss-free charge transport at the same time. Using small molecule and polymer blend systems, recent efforts highlight the problems to ensure an optimized relationship between molecular structure, morphology and device properties. Here, we present two examples using a host/guest mixture approach for the controlled, sequential design of bilayer organic solar cell architectures that consist of a large interface area with connecting paths to the respective electrodes at the same time. In the first example, we employed polymer demixing during spin coating to produce a rough interface: surface directed spinodal decomposition leads to a 2-dimensional spinodal pattern with submicrometer features at the polymer-polymer interface. The second system consists of a solution of a blend of small molecules, where phase separation into a bilayer during spin coating is followed by dewetting. For both cases, the guest can be removed using a selective solvent after the phase separation process, and the rough host surface can be covered with a second active, semiconducting component. We explain the potential merits of the resulting interdigitated bilayer films, and explore to which extent polymer-polymer and surface interactions can be employed to create surface features in the nanometer range.

  1. Have Periprosthetic Hip Infection Rates Plateaued?

    Science.gov (United States)

    Perfetti, Dean C; Boylan, Matthew R; Naziri, Qais; Paulino, Carl B; Kurtz, Steven M; Mont, Michael A

    2017-07-01

    Periprosthetic joint infection (PJI) is a serious complication of total hip arthroplasty (THA). Although the number of revision cases is increasing, the prevalence of PJI as an indication for revision surgery, and the variability of this indication among surgeons and hospitals, is unclear. The New York Statewide Planning and Research Cooperative System was used to identify 33,582 patients undergoing revision THA between 2000 and 2013. PJI was identified using International Classification of Diseases, Ninth Revision diagnosis codes. Volume was defined using mean number of revision THAs performed annually by each hospital and surgeon. PJI was the indication for 13.0% of all revision THAs. The percentage of revision THAs for PJI increased between years 2000 and 2007 (odds ratio [OR] = 1.05, P < .001), but decreased between years 2008 and 2013 (OR = 0.96, P = .001). Compared to medium-volume hospitals, the PJI burden at high-volume hospitals decreased during years 2000-2007 (OR = 0.58, P < .001) and 2008-2013 (OR = 0.57, P < .001). Compared to medium-volume surgeons, the PJI burden for high-volume surgeons increased during years 2000-2007 (OR = 1.39, P < .001), but did not differ during years 2008-2013 (P = .618). The burden of PJI as an indication for revision THA may be plateauing. High-volume institutions have seen decreases in the percentage of revisions performed for PJI over the complete study duration. Specific surgeon may be associated with the plateauing in PJI rates as high-volume surgeons in 2008-2013 were no longer found to be at increased risk of PJI as an indication for revision THA. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Contact size scaling of a W-contact phase-change memory cell based on numerical simulation

    Institute of Scientific and Technical Information of China (English)

    Wei Yiqun; Lin Xinnan; Jia Yuchao; Cui Xiaole; Zhang Xing; Song Zhitang

    2012-01-01

    In the design of phase-change memory (PCM),it is important to perform numerical simulations to predict the performances of different device structures.This work presents a numerical simulation using a coupled system including Poisson's equation,the current continuity equation,the thermal conductivity equation,and phase-change dynamics to simulate the thermal and electric characteristics of phase-change memory.This method discriminates the common numerical simulation of PCM cells,from which it applies Possion's equation and current continuity equations instead of the Laplace equation to depict the electric characteristics of PCM cells,which is more adoptable for the semiconductor characteristics of phase-change materials.The results show that the simulation agrees with the measurement,and the scalability of PCM is predicted.

  3. A new approach for determining phase response curves reveals that Purkinje cells can act as perfect integrators.

    Directory of Open Access Journals (Sweden)

    Elena Phoka

    2010-04-01

    Full Text Available Cerebellar Purkinje cells display complex intrinsic dynamics. They fire spontaneously, exhibit bistability, and via mutual network interactions are involved in the generation of high frequency oscillations and travelling waves of activity. To probe the dynamical properties of Purkinje cells we measured their phase response curves (PRCs. PRCs quantify the change in spike phase caused by a stimulus as a function of its temporal position within the interspike interval, and are widely used to predict neuronal responses to more complex stimulus patterns. Significant variability in the interspike interval during spontaneous firing can lead to PRCs with a low signal-to-noise ratio, requiring averaging over thousands of trials. We show using electrophysiological experiments and simulations that the PRC calculated in the traditional way by sampling the interspike interval with brief current pulses is biased. We introduce a corrected approach for calculating PRCs which eliminates this bias. Using our new approach, we show that Purkinje cell PRCs change qualitatively depending on the firing frequency of the cell. At high firing rates, Purkinje cells exhibit single-peaked, or monophasic PRCs. Surprisingly, at low firing rates, Purkinje cell PRCs are largely independent of phase, resembling PRCs of ideal non-leaky integrate-and-fire neurons. These results indicate that Purkinje cells can act as perfect integrators at low firing rates, and that the integration mode of Purkinje cells depends on their firing rate.

  4. Context based mixture model for cell phase identification in automated fluorescence microscopy

    Directory of Open Access Journals (Sweden)

    Zhou Xiaobo

    2007-01-01

    Full Text Available Abstract Background Automated identification of cell cycle phases of individual live cells in a large population captured via automated fluorescence microscopy technique is important for cancer drug discovery and cell cycle studies. Time-lapse fluorescence microscopy images provide an important method to study the cell cycle process under different conditions of perturbation. Existing methods are limited in dealing with such time-lapse data sets while manual analysis is not feasible. This paper presents statistical data analysis and statistical pattern recognition to perform this task. Results The data is generated from Hela H2B GFP cells imaged during a 2-day period with images acquired 15 minutes apart using an automated time-lapse fluorescence microscopy. The patterns are described with four kinds of features, including twelve general features, Haralick texture features, Zernike moment features, and wavelet features. To generate a new set of features with more discriminate power, the commonly used feature reduction techniques are used, which include Principle Component Analysis (PCA, Linear Discriminant Analysis (LDA, Maximum Margin Criterion (MMC, Stepwise Discriminate Analysis based Feature Selection (SDAFS, and Genetic Algorithm based Feature Selection (GAFS. Then, we propose a Context Based Mixture Model (CBMM for dealing with the time-series cell sequence information and compare it to other traditional classifiers: Support Vector Machine (SVM, Neural Network (NN, and K-Nearest Neighbor (KNN. Being a standard practice in machine learning, we systematically compare the performance of a number of common feature reduction techniques and classifiers to select an optimal combination of a feature reduction technique and a classifier. A cellular database containing 100 manually labelled subsequence is built for evaluating the performance of the classifiers. The generalization error is estimated using the cross validation technique. The

  5. 飞行员高原驻训后脱习服观察%Deacclimatization observation for the pilots off the station in plateau

    Institute of Scientific and Technical Information of China (English)

    王林; 焦玉冰; 薛红; 李英秋; 李卫东; 杨蕾; 单庆顺; 许也齐; 汪东军

    2014-01-01

    目的 研究高原环境对飞行员身心健康状态的影响及脱习服产生的主要医学问题.方法 高原驻训3个月返回平原后第4天,对19名飞行员进行高原驻训后脱习服反应问卷调查;高原驻训1个月和返回平原后1周分别对11名飞行员进行影像学检查;高原驻训3个月返回平原后第2天,对6名飞行员的生化指标进行检测. 结果 19名飞行员均出现了不同程度的脱习服反应,其中84.2%的人认为高原脱习服对工作、生活产生一定的影响.与驻训1个月比较,返回平原后1周11名飞行员肝左叶上下径减小(t=3.211,P<0.05).与驻训1个月比较,返回平原后1周,V5导联R波与V1导联S波之和明显减低(t=2.422,P<0.05).返回平原后1周,飞行员收缩期肺动脉瓣射血达最高所需时间较在高原时明显增加(t=3.854,P<0.05).高原驻训3个月,6名飞行员的红细胞、血红蛋白、尿酸、总胆红素、甘油三酯、胱抑素L1、补体C4和白介素-10明显高于参考值(t=2.601~7.537,P<0.05),免疫球蛋白A、转化生长因子β明显低于参考值(t=2.731、16.824,P<0.05). 结论 影像学、心电图和生化检查均证实高原环境对飞行员产生影响.建议进入高原前对飞行员采取相应的防护措施,返回平原后实施有效的医疗康复工作.%Objective To study the influences of plateau environment on pilots' physical and mental health and the major medical problems generated in deacclimatization.Methods Nineteen pilots were selected to answer the questionnaires on the subject of deacclimatization on the 4th day after their 3-month plateau stationing.Eleven pilots were detected by radiology in 2 phases:one-month plateau stationing and one week after plateau stationing.On the 2nd day after 3-month plateau stationing,6 pilots' biochemical indicators were tested.Results Nineteen pilots showed various degrees of symptoms in deacclimatization and 84.2 % of them complained that the

  6. Metabolic flux analysis of CHO cells at growth and non-growth phases using isotopic tracers and mass spectrometry.

    Science.gov (United States)

    Ahn, Woo Suk; Antoniewicz, Maciek R

    2011-09-01

    Chinese hamster ovary (CHO) cells are the main platform for production of biotherapeutics in the biopharmaceutical industry. However, relatively little is known about the metabolism of CHO cells in cell culture. In this work, metabolism of CHO cells was studied at the growth phase and early stationary phase using isotopic tracers and mass spectrometry. CHO cells were grown in fed-batch culture over a period of six days. On days 2 and 4, [1,2-(13)C] glucose was introduced and the labeling of intracellular metabolites was measured by gas chromatography-mass spectrometry (GC-MS) at 6, 12 and 24h following the introduction of tracer. Intracellular metabolic fluxes were quantified from measured extracellular rates and (13)C-labeling dynamics of intracellular metabolites using non-stationary (13)C-metabolic flux analysis ((13)C-MFA). The flux results revealed significant rewiring of intracellular metabolic fluxes in the transition from growth to non-growth, including changes in energy metabolism, redox metabolism, oxidative pentose phosphate pathway and anaplerosis. At the exponential phase, CHO cell metabolism was characterized by a high flux of glycolysis from glucose to lactate, anaplerosis from pyruvate to oxaloacetate and from glutamate to α-ketoglutarate, and cataplerosis though malic enzyme. At the stationary phase, the flux map was characterized by a reduced flux of glycolysis, net lactate uptake, oxidative pentose phosphate pathway flux, and reduced rate of anaplerosis. The fluxes of pyruvate dehydrogenase and TCA cycle were similar at the exponential and stationary phase. The results presented here provide a solid foundation for future studies of CHO cell metabolism for applications such as cell line development and medium optimization for high-titer production of recombinant proteins.

  7. Research, development and demonstration of a fuel cell/battery powered bus system. Phase 1, Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1990-02-28

    Purpose of the Phase I effort was to demonstrate feasibility of the fuel cell/battery system for powering a small bus (under 30 ft or 9 m) on an urban bus route. A brassboard powerplant was specified, designed, fabricated, and tested to demonstrate feasibility in the laboratory. The proof-of-concept bus, with a powerplant scaled up from the brassboard, will be demonstrated under Phase II.

  8. Solid Phase Red Cell Adherence Assay: a tubeless method for pretransfusion testing and other applications in transfusion science.

    Science.gov (United States)

    Ching, Eric

    2012-06-01

    Solid Phase Red Cell Adherence Assay (SPRCA) is one of the two tubeless methods developed to improve sensitivity and specificity in blood group serology. The SPRCA (solid phase) and the column agglutination (gel) technology have gained wide acceptance following successful adaptation to fully automated platforms, The purpose of this paper is to discuss the development, principle, procedures as well as laboratory and clinical applications of the SPRCA in transfusion medicine.

  9. Effects of the soil freeze-thaw process on the regional climate of the Tibet Plateau

    Science.gov (United States)

    Luo, S., Sr.; Chen, B.; Lu, S.; Zhang, Y.; Ma, D.

    2015-12-01

    Single-point and regional simulation experiments on the Tibet Plateau, both with and without consideration of the soil freeze-thaw process, were set up with CLM3.5 and RegCM4 models. Comparison of the simulated soil temperature and moisture, surface energy flux, and upper-lower atmospheric circulation showed that the regional climate can be influenced by the freeze-thaw process of soil. The results indicate that the freeze-thaw process is a buffer to the seasonal changes in soil and near-surface temperatures and strengthens the energy exchange between the soil and the atmosphere. During the freeze (thaw) process, releasing (absorbing) of phase change energy retards the cooling (heating) effect of air temperature on soil. The soil freeze-thaw process increases (decreases) the surface heat source of the plateau in winter (summer), which increases (decreases) the near-surface temperature in winter (summer). Promoted by atmospheric circulation, the soil freeze-thaw process influences climate at the high and low altitudes of the plateau; this may also contribute to the maintenance of the South Asia High. In the early stages of permafrost degradation, the regional climate effects of freezing and thawing may accelerate the degradation of permafrost.

  10. Mesozoic denudation and cooling events of the Yinshan Mountains, southern Mongolian Plateau

    Science.gov (United States)

    Feng, Li-Xia; Han, Bao-Fu; Wang, Zeng-Zhen; Liu, Bo; Brown, Roderick

    2016-04-01

    ABASTRACT The Yinshan Mountains are south boundary of the Mongolian Plateau, occupying the north part of North China Craton. 18 granitoid samples were conducted by apatite fission track method in order to unravel its Mesozoic denudation and cooling history and relationship with the Mongolian Plateau. They obtain Jurassic to Cretaceous AFT ages. 3 main phases of rapid cooling events during Mesozoic are recognized and could probably be caused by denudation. Combined with local geological conditions, denudations are more likely controlled by the local thrust faulting. The Early Jurassic denudation event occurred in the transition area to the Mongolian Plateau. The Late Jurassic to Early Cretaceous denudation events occurred in the interior mountains and are more likely provoked by the distant effect of the Mongol-Okhotsk Orogeny based on their propagation directions. The Late Cretaceous denudation event occurred in the southeastern flank of the mountain. Finally, the activity time of thrust faults are constrained by 130-90 Ma according to the uplift and denudation relationship in the thrust system and their modeling T-t paths. Key words Apatite Fission track; Uplift and denudation; Mesozoic reactivation; Mountain Langshan

  11. Constraining the stepwise migration of the eastern Tibetan Plateau margin by apatite fission track thermochronology

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Granites sampled from Garzê-Litang thrust, Longmen Shan thrust, Garzê and Litang strike-slip faults in the eastern Tibetan Plateau have been analyzed with apatite fission track thermochronological method in this study. The measured fission track apparent ages, combined with the simulated annealing mod- eling of the thermal history, have been used to reconstruct the thermal evolutionary histories of the samples and interpret the active history of the thrusts and faults in these areas. Thermal history mod- eling shows that earlier tectonic cooling occurred in the Garzê-Litang thrust in Miocene (~20―16 Ma) whereas the later cooling occurred mainly in the Longmen Shan thrust since ~5 Ma. Our study sug- gests that the margin of eastern Tibetan Plateau was extended by stages: through strike-slip faults deformations and related thrusts, the upper crust formed the Garzê-Litang margin in the Miocene epoch and then moved to the Longmen Shan margin since ~5 Ma. During this process, the deformations of different phases in the eastern Tibetan Plateau were absorbed by the thrusts within them and conse- quently the tectonic events of long-distance slip and extrusion up to hundreds of kilometers have not been found.

  12. Constraining the stepwise migration of the eastern Tibetan Plateau margin by apatite fission track thermochronology

    Institute of Scientific and Technical Information of China (English)

    LAI QingZhou; DING Lin; WANG HongWei; YUE YaHui; CAI FuLong

    2007-01-01

    Granites sampled from Garzê-Litang thrust, Longmen Shan thrust, Garzê and Litang strike-slip faults in the eastern Tibetan Plateau have been analyzed with apatite fission track thermochronological method in this study. The measured fission track apparent ages, combined with the simulated annealing modeling of the thermal history, have been used to reconstruct the thermal evolutionary histories of the samples and interpret the active history of the thrusts and faults in these areas. Thermal history modeling shows that earlier tectonic cooling occurred in the Garzê-Litang thrust in Miocene (~20―16 Ma) whereas the later cooling occurred mainly in the Longmen Shan thrust since ~5 Ma. Our study suggests that the margin of eastern Tibetan Plateau was extended by stages: through strike-slip faults deformations and related thrusts, the upper crust formed the Garzê-Litang margin in the Miocene epoch and then moved to the Longmen Shan margin since ~5 Ma. During this process, the deformations of different phases in the eastern Tibetan Plateau were absorbed by the thrusts within them and consequently the tectonic events of long-distance slip and extrusion up to hundreds of kilometers have not been found.

  13. On the inward drift of runaway electrons in plateau regime

    CERN Document Server

    Hu, Di

    2016-01-01

    The well observed inward drift of current carrying runaway electrons during runaway plateau regime after disruption is studied by considering the phase space dynamic of runaways in a large aspect ratio toroidal system. We consider the case where the toroidal field is unperturbed and the toroidal symmetry of the system is preserved. The invariance of canonical angular momentum in such system requires runaways to drift horizontally in configuration space for any given change in momentum space. The dynamic of this drift can be obtained by taking the variation of canonical angular momentum. It is then found that runaway electrons will always drift inward as long as they are decelerating. This drift motion is essentially non-linear, since the current is carried by runaways themselves, and any runaway drift relative to the magnetic axis will cause further displacement of the axis itself. A simplified analytical model is constructed to describe such inward drift both in ideal wall case and no wall case, and the runa...

  14. Response of thyroid follicular cells to gamma irradiation compared to proton irradiation. I. Initial characterization of DNA damage, micronucleus formation, apoptosis, cell survival, and cell cycle phase redistribution

    Science.gov (United States)

    Green, L. M.; Murray, D. K.; Bant, A. M.; Kazarians, G.; Moyers, M. F.; Nelson, G. A.; Tran, D. T.

    2001-01-01

    .12 Gy(-1) for protons), which suggests that the higher level of survival of gamma-irradiated cells could be attributed to the persistence of nonlethally irradiated thyrocytes and/or the capacity to repair damage more effectively than cells exposed to equal physical doses of protons. The final assessment in this study was radiation-induced cell cycle phase redistribution. Gamma rays and protons produced a similar dose-dependent redistribution toward a predominantly G(2)-phase population. From our cumulative results, it seems likely that a majority of the proton-irradiated cells would not continue to divide. In conclusion, these findings suggest that there are quantitative and qualitative differences in the biological effects of proton beams and gamma rays. These differences could be due to structured energy deposition from the tracks of primary protons and the associated high-LET secondary particles produced in the targets. The results suggest that a simple dose-equivalent approach to dosimetry may be inadequate to compare the biological responses of cells to photons and protons.

  15. Characterizing dynamic hysteresis and fractal statistics of chaotic two-phase flow and application to fuel cells

    Science.gov (United States)

    Burkholder, Michael B.; Litster, Shawn

    2016-05-01

    In this study, we analyze the stability of two-phase flow regimes and their transitions using chaotic and fractal statistics, and we report new measurements of dynamic two-phase pressure drop hysteresis that is related to flow regime stability and channel water content. Two-phase flow dynamics are relevant to a variety of real-world systems, and quantifying transient two-phase flow phenomena is important for efficient design. We recorded two-phase (air and water) pressure drops and flow images in a microchannel under both steady and transient conditions. Using Lyapunov exponents and Hurst exponents to characterize the steady-state pressure fluctuations, we develop a new, measurable regime identification criteria based on the dynamic stability of the two-phase pressure signal. We also applied a new experimental technique by continuously cycling the air flow rate to study dynamic hysteresis in two-phase pressure drops, which is separate from steady-state hysteresis and can be used to understand two-phase flow development time scales. Using recorded images of the two-phase flow, we show that the capacitive dynamic hysteresis is related to channel water content and flow regime stability. The mixed-wettability microchannel and in-channel water introduction used in this study simulate a polymer electrolyte fuel cell cathode air flow channel.

  16. Characterizing dynamic hysteresis and fractal statistics of chaotic two-phase flow and application to fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Burkholder, Michael B.; Litster, Shawn, E-mail: litster@andrew.cmu.edu [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

    2016-05-15

    In this study, we analyze the stability of two-phase flow regimes and their transitions using chaotic and fractal statistics, and we report new measurements of dynamic two-phase pressure drop hysteresis that is related to flow regime stability and channel water content. Two-phase flow dynamics are relevant to a variety of real-world systems, and quantifying transient two-phase flow phenomena is important for efficient design. We recorded two-phase (air and water) pressure drops and flow images in a microchannel under both steady and transient conditions. Using Lyapunov exponents and Hurst exponents to characterize the steady-state pressure fluctuations, we develop a new, measurable regime identification criteria based on the dynamic stability of the two-phase pressure signal. We also applied a new experimental technique by continuously cycling the air flow rate to study dynamic hysteresis in two-phase pressure drops, which is separate from steady-state hysteresis and can be used to understand two-phase flow development time scales. Using recorded images of the two-phase flow, we show that the capacitive dynamic hysteresis is related to channel water content and flow regime stability. The mixed-wettability microchannel and in-channel water introduction used in this study simulate a polymer electrolyte fuel cell cathode air flow channel.

  17. Energy Efficient Aluminum Production - Pilot-Scale Cell Tests - Final Report for Phase I and Phase II

    Energy Technology Data Exchange (ETDEWEB)

    R. A. Christini

    1999-12-30

    A cermet anode that produces oxygen and a cathode material that is wetted by aluminum can provide a dimensionally stable inter-electrode distance in the Hall-Heroult cell. This can be used to greatly improve the energy and/or productivity efficiencies. The concept, which was developed and tested, uses a system of vertically interleaved anodes and cathodes. The major advantage of this concept is the significant increase in electrochemical surface area compared to a horizontal orientation of anode and cathode that is presently used in the Hall-Heroult process. This creates an additional advantage for energy reduction of 1.3 kWh/lb or a 20% productivity improvement. The voltages obtained in an optimized cell test met the energy objectives of the project for at least two weeks. An acceptable current efficiency was never proven, however, during either pilot scale or bench scale tests with the vertical plate configuration. This must be done before a vertical cell can be considered viab le. Anode corrosion rate must be reduced by at least a factor of three in order to produce commercial purity aluminum. It is recommended that extensive theoretical and bench scale investigations be done to improve anode materials and to demonstrate acceptable current efficiencies in a vertical plate cell before pilot scale work is continued.

  18. Temporal and spatial evolution of the standardized precipitation evapotranspiration index (SPEI) in the Loess Plateau under climate change from 2001 to 2050.

    Science.gov (United States)

    Gao, Xuerui; Zhao, Qi; Zhao, Xining; Wu, Pute; Pan, Wenxiang; Gao, Xiaodong; Sun, Miao

    2017-10-01

    Loess Plateau has great uncertainty on drought occurrence due to climate change. This paper analyzes the evolution of precipitation, potential evapotranspiration and standardized precipitation evapotranspiration index (SPEI) based on the Coupled Model Inter-comparison Project Phase 5 (CMIP5) data and regional downscaling model (RegCM4.0). Results indicate that, under RCP2.6 Scenario, the precipitation will increase significantly (5% confidence level) at the rate of 16.40mm/10a. However, the potential evapotranspiration is showing non-significant decreasing trend at the rate of 2.16mm/10a. Moreover, the SPEI will decrease in the south and northernmost area and increase in the central northern area of Loess Plateau. Under RCP8.5 Scenario, the precipitation will increase significantly (5% confidence level) at the rate of 19.12mm/10a. The potential evapotranspiration will non-significantly decrease at the rate of 2.16mm/10a and the SPEI is showing increasing trend almost in the whole Loess Plateau. Generally, Loess Plateau is becoming wetter in the central part under RCP2.6 Scenario and the wet area will be enlarged to almost the whole plateau under RCP8.5 Scenario. Based on the results, the water resources will increase under global warming, which may alleviate the water scarcity issue in the Loess Plateau. Copyright © 2017. Published by Elsevier B.V.

  19. Mechanisms and modeling development of water transport/phase change in catalyst layers of portion exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Yexiang [Dept. of Thermal Engineering, Tsinghua University Beijing (China)], email: Yexiang.Xiao@energy.lth.se; Yuan, Jinliang; Sunden, Bengt [Dept. of Energy Sciences, Faculty of Engineering, Lund University (Sweden)], email: Jinliang.yuan@energy.lth.se, email: bengt.sunden@energy.lth.se

    2011-07-01

    Research on proton exchange membrane fuel cells has shown that incorporation of nanosized catalysts can effectively increase active areas and catalyst activity and make a great contribution to development in performance and catalyst utilization. Multiphase transport processes are as significant and complicated as water generation/transfer processes which occur in nano-structured catalyst layers. A review project has been launched aimed at gaining a comprehensive understanding of the mechanisms of water generation or transport phenomena. It covers catalytic reactions and water-phase change within the catalyst layers. The review proceeds in three main stages: Firstly, it characterizes and reconstructs the nano/micro-structured pores and solid-phases; secondly, it emphasises the importance of sensitive and consistent analysis of various water-phase change and transport schemes; and thirdly, it recommends development of microscopic models for multi-phase transport processes in the pores and the solid phases.

  20. Compact, common path quantitative phase microscopic techniques for imaging cell dynamics

    Indian Academy of Sciences (India)

    A Anand; P Vora; S Mahajan; V Trivedi; V Chhaniwal; A Singh; R Leitgeb; B Javidi

    2014-01-01

    Microscopy using visible electromagnetic radiation can be used to investigate living cells in various environments. But bright field microscopy only provides two-dimensional (2D) intensity distribution at a single object plane. One of the ways to retrieve object height/thickness information is to employ quantitative phase microscopic (QPM) techniques. Interferometric QPM techniques are widely used for this. Digital holographic microscopy (DHM) is one of the stateof-the-art methods for quantitative three-dimensional (3D) imaging. Usually it is implemented in two-beam geometry, which is prone to mechanical vibrations. But to study dynamics of objects like red blood cells, one needs temporal stability much better than the fluctuations of the object, which the two-beam geometry fails to deliver. One way to overcome this hurdle is to use selfreferencing techniques, in which a portion of the object beam will act as the reference beam. Here the development of self-referencing QPM techniques is described along with the results.

  1. A phase-contrast microscopy-based method for modeling the mechanical behavior of mesenchymal stem cells.

    Science.gov (United States)

    Saeed, Mayssam; Sharabani-Yosef, Orna; Weihs, Daphne; Gefen, Amit

    2016-10-01

    We present three-dimensional (3D) finite element (FE) models of single, mesenchymal stem cells (MSCs), generated from images obtained by optical phase-contrast microscopy and used to quantify the structural responses of the studied cells to externally applied mechanical loads. Mechanical loading has been shown to affect cell morphology and structure, phenotype, motility and other biological functions. Cells experience mechanical loads naturally, yet under prolonged or sizable loading, damage and cell death may occur, which motivates research regarding the structural behavior of loaded cells. For example, near the weight-bearing boney prominences of the buttocks of immobile persons, tissues may become highly loaded, eventually leading to massive cell death that manifests as pressure ulcers. Cell-specific computational models have previously been developed by our group, allowing simulations of cell deformations under compressive or stretching loads. These models were obtained by reconstructing specific cell structures from series of 2D fluorescence, confocal image-slices, requiring cell-specific fluorescent-staining protocols and costly (confocal) microscopy equipment. Alternative modeling approaches represent cells simply as half-spheres or half-ellipsoids (i.e. idealized geometries), which neglects the curvature details of the cell surfaces associated with changes in concentrations of strains and stresses. Thus, we introduce here for the first time an optical image-based FE modeling, where loads are simulated on reconstructed 3D geometrical cell models from a single 2D, phase-contrast image. Our novel modeling method eliminates the need for confocal imaging and fluorescent staining preparations (both expensive), and makes cell-specific FE modeling affordable and accessible to the biomechanics community. We demonstrate the utility of this cost-effective modeling method by performing simulations of compression of MSCs embedded in a gel.

  2. Aqueous two-phase partition applied to the isolation of plasma membranes and Golgi apparatus from cultured mammalian cells

    Science.gov (United States)

    Morre, D. M.; Morre, D. J.

    2000-01-01

    Partitioning in dextran-poly(ethylene)glycol (PEG) aqueous-aqueous phase systems represents a mature technology with many applications to separations of cells and to the preparation of membranes from mammalian cells. Most applications to membrane isolation and purification have focused on plasma membranes, plasma membrane domains and separation of right side-out and inside-out plasma membrane vesicles. The method exploits a combination of membrane properties, including charge and hydrophobicity. Purification is based upon differential distributions of the constituents in a sample between the two principal compartments of the two phases (upper and lower) and at the interface. The order of affinity of animal cell membranes for the upper phase is: endoplasmic reticulum two-phase partition with other procedures to obtain a more highly purified preparation. A procedure is described for preparation of Golgi apparatus from transformed mammalian cells that combines aqueous two-phase partition and centrifugation. Also described is a periodic NADH oxidase, a new enzyme marker for right side-out plasma membrane vesicles not requiring detergent disruptions for measurement of activity.

  3. A study of the low-luminosity Type II-Plateau supernova 2008bk

    Science.gov (United States)

    Lisakov, S. M.; Dessart, Luc; Hillier, D. John; Waldman, Roni; Livne, Eli

    2017-04-01

    Supernova (SN) 2008bk is a well-observed low-luminosity Type II event visually associated with a low-mass red-supergiant progenitor. To model SN 2008bk, we evolve a 12 M⊙ star from the main sequence until core collapse, when it has a total mass of 9.88 M⊙, a He-core mass of 3.22 M⊙ and a radius of 502 R⊙. We then artificially trigger an explosion that produces 8.29 M⊙ of ejecta with a total energy of 2.5 × 1050 erg and ∼0.009 M⊙ of 56Ni. We model the subsequent evolution of the ejecta with non-local thermodynamic equilibrium time-dependent radiative transfer. Although somewhat too luminous and energetic, this model reproduces satisfactorily the multiband light curves and multi-epoch spectra of SN 2008bk, confirming the suitability of a low-mass massive star progenitor. As in other low-luminosity SNe II, the structured Hα profile at the end of the plateau phase is probably caused by Ba II 6496.9 Å rather than asphericity. We discuss the sensitivity of our results to changes in progenitor radius and mass, as well as chemical mixing. A 15 per cent increase in progenitor radius causes a 15 per cent increase in luminosity and a 0.2 mag V-band brightening of the plateau but leaves its length unaffected. An increase in ejecta mass by 10 per cent lengthens the plateau by ∼10 d. Chemical mixing introduces slight changes to the bolometric light curve, limited to the end of the plateau, but has a large impact on colours and spectra at nebular times.

  4. The selective oxidation of toluene to benzaldehyde applying a fuel cell system in the gas phase

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, K.; Ishizuka, K.; Yamanaka, I.; Hatano, M. (Dept. of Chemical Engineering, Tokyo Inst. of Technology, Ookayama, Meguro-ku, Tokyo 152 (JP))

    1991-11-01

    This paper discusses a fuel cell system used for the synthesis of benzaldehyde from toluene in the gas phase. The cell system (anode: Pd-black with added graphite/H{sub 3}PO{sub 4}(aq.)/cathode: Pt-black with added graphite) operated at ca. 373 K under short-circuit conditions and produced the partial oxidation products benzaldehyde (PhCHO) and benzoic acid (PhCOOH). The addition of chlorides such as HCl, NaCl, MgCl{sub 2}, etc., to the anode remarkably improved the selectivity of the sum of PhCHO and PhCOOH. In the presence of chlorides, CO{sub 2} was not produced at all. Among the chlorides tested, NaCl is the best additive for the synthesis of PhCHO. Kinetic results on the reaction with the NaCl-added anode have shown that decreasing temperatures and increasing pressures of the reactants (toluene and O{sub 2}) favor the oxidation to PhCHO. The oxidation of toluene under an externally applied potential showed a product distribution similar to that observed under short-circuit conditions. The turnover number grater than unite (2.4) indicates catalytic cycling of the Pd in the anode. The current efficiency was improved by cyclic short- and open-circuit operation of the cell. A reaction mechanism assuming a {pi} allylbenzyl-Pd{sup 2+} (ligand){sub x} complex as the reaction intermediate explains the kinetic results and the favorable effect of chloride. The intermediate complex may be generated through the electrochemical oxidation of Pd and toluene. The subsequent competitive formations of PhCHO and CO{sub 2} from this complex proceed nonelectrochemically.

  5. S-phase duration is the main target of cell cycle regulation in neural progenitors of developing ferret neocortex.

    Science.gov (United States)

    Turrero García, Miguel; Chang, YoonJeung; Arai, Yoko; Huttner, Wieland B

    2016-02-15

    The evolutionary expansion of the neocortex primarily reflects increases in abundance and proliferative capacity of cortical progenitors and in the length of the neurogenic period during development. Cell cycle parameters of neocortical progenitors are an important determinant of cortical development. The ferret (Mustela putorius furo), a gyrencephalic mammal, has gained increasing importance as a model for studying corticogenesis. Here, we have studied the abundance, proliferation, and cell cycle parameters of different neural progenitor types, defined by their differential expression of the transcription factors Pax6 and Tbr2, in the various germinal zones of developing ferret neocortex. We focused our analyses on postnatal day 1, a late stage of cortical neurogenesis when upper-layer neurons are produced. Based on cumulative 5-ethynyl-2'-deoxyuridine (EdU) labeling as well as Ki67 and proliferating cell nuclear antigen (PCNA) immunofluorescence, we determined the duration of the various cell cycle phases of the different neocortical progenitor subpopulations. Ferret neocortical progenitors were found to exhibit longer cell cycles than those of rodents and little variation in the duration of G1 among distinct progenitor types, also in contrast to rodents. Remarkably, the main difference in cell cycle parameters among the various progenitor types was the duration of S-phase, which became shorter as progenitors progressively changed transcription factor expression from patterns characteristic of self-renewal to those of neuron production. Hence, S-phase duration emerges as major target of cell cycle regulation in cortical progenitors of this gyrencephalic mammal.

  6. Global histone modification fingerprinting in human cells using epigenetic reverse phase protein array

    Science.gov (United States)

    Partolina, Marina; Thoms, Hazel C; MacLeod, Kenneth G; Rodriguez-Blanco, Giovanny; Clarke, Matthew N; Venkatasubramani, Anuroop V; Beesoo, Rima; Larionov, Vladimir; Neergheen-Bhujun, Vidushi S; Serrels, Bryan; Kimura, Hiroshi; Carragher, Neil O; Kagansky, Alexander

    2017-01-01

    The balance between acetylation and deacetylation of histone proteins plays a critical role in the regulation of genomic functions. Aberrations in global levels of histone modifications are linked to carcinogenesis and are currently the focus of intense scrutiny and translational research investments to develop new therapies, which can modify complex disease pathophysiology through epigenetic control. However, despite significant progress in our understanding of the molecular mechanisms of epigenetic machinery in various genomic contexts and cell types, the links between epigenetic modifications and cellular phenotypes are far from being clear. For example, enzymes controlling histone modifications utilize key cellular metabolites associated with intra- and extracellular feedback loops, adding a further layer of complexity to this process. Meanwhile, it has become increasingly evident that new assay technologies which provide robust and precise measurement of global histone modifications are required, for at least two pressing reasons: firstly, many approved drugs are known to influence histone modifications and new cancer therapies are increasingly being developed towards targeting histone deacetylases (HDACs) and other epigenetic readers and writers. Therefore, robust assays for fingerprinting the global effects of such drugs on preclinical cell, organoid and in vivo models is required; and secondly, robust histone-fingerprinting assays applicable to patient samples may afford the development of next-generation diagnostic and prognostic tools. In our study, we have used a panel of monoclonal antibodies to determine the relative changes in the global abundance of post-translational modifications on histones purified from cancer cell lines treated with HDAC inhibitors using a novel technique, called epigenetic reverse phase protein array. We observed a robust increase in acetylation levels within 2–24 h after inhibition of HDACs in different cancer cell lines

  7. Involvement of the p38 MAPK signaling pathway in S-phase cell-cycle arrest induced by Furazolidone in human hepatoma G2 cells.

    Science.gov (United States)

    Sun, Yu; Tang, Shusheng; Jin, Xi; Zhang, Chaoming; Zhao, Wenxia; Xiao, Xilong

    2013-12-01

    Given the previously described essential role for the p38 mitogen-activation protein kinase (p38 MAPK) signaling pathway in human hepatoma G2 cells (HepG2), we undertook the present study to investigate the role of the p38 MAPK signaling pathway in cell-cycle arrest induced by Furazolidone (FZD). The aim of this study was to determine the effects of FZD on HepG2 cells by activating and inhibiting the p38 MAPK signaling pathway. The cell cycle and proliferation of HepG2 cells treated with FZD were detected by flow cytometry and MTT assay in the presence or absence of p38 MAPK inhibitors (SB203580), respectively. Cyclin D1, cyclin D3 and CDK6 were detected by quantitative real-time PCR and western blot analysis. Our data showed that p38 MAPK became phosphorylated after stimulation with FZD. Activation of p38 MAPK could arise S-phase cell-cycle arrest and suppress cell proliferation. Simultaneously, inhibition of the p38 MAPK signaling pathway significantly prevented S-phase cell-cycle arrest, increased the percentage of cell viability and decreased the expression of cyclin D1, cyclin D3 and CDK6. These results demonstrated that FZD arose S-phase cell-cycle arrest via activating the p38 MAPK signaling pathway in HepG2 cells. Cyclin D1, cyclin D3 and CDK6 are target genes functioning at the downstream of p38 MAPK in HepG2 cells induced by FZD.

  8. A generalised age- and phase-structured model of human tumour cell populations both unperturbed and exposed to a range of cancer therapies.

    Science.gov (United States)

    Basse, Britta; Ubezio, Paolo

    2007-07-01

    We develop a general mathematical model for a population of cells differentiated by their position within the cell division cycle. A system of partial differential equations governs the kinetics of cell densities in certain phases of the cell division cycle dependent on time t (hours) and an age-like variable tau (hours) describing the time since arrival in a particular phase of the cell division cycle. Transition rate functions control the transfer of cells between phases. We first obtain a theoretical solution on the infinite domain -infinity course, these age distributions are unknown. All is not lost, however, because a cell line before treatment usually lies in a state of asynchronous balanced growth where the proportion of cells in each phase of the cell cycle remain constant. We assume that an unperturbed cell line has four distinct phases and that the rate of transition between phases is constant within a short period of observation ('short' relative to the whole history of the tumour growth) and we show that under certain conditions, this is equivalent to exponential growth or decline. We can then gain expressions for the age distributions. So, in short, our approach is to assume that we have an unperturbed cell line on t cell line is exposed to cancer therapy. This corresponds to a change in the transition rate functions and perhaps incorporation of additional phases of the cell cycle. We discuss a number of these cancer therapies and applications of the model.

  9. 60 Hz electric field changes the membrane potential during burst phase in pancreatic β-cells: in silico analysis.

    Science.gov (United States)

    Neves, Gesilda F; Silva, José R F; Moraes, Renato B; Fernandes, Thiago S; Tenorio, Bruno M; Nogueira, Romildo A

    2014-06-01

    The production, distribution and use of electricity can generate low frequency electric and magnetic fields (50-60 Hz). Considering that some studies showed adverse effects on pancreatic β-cells exposed to these fields; the present study aimed to analyze the effects of 60 Hz electric fields on membrane potential during the silent and burst phases in pancreatic β-cells using a mathematical model. Sinusoidal 60 Hz electric fields with amplitude ranging from 0.5 to 4 mV were applied on pancreatic β-cells model. The sinusoidal electric field changed burst duration, inter-burst intervals (silent phase) and spike sizes. The parameters above presented dose-dependent response with the voltage amplitude applied. In conclusion, theoretical analyses showed that a 60 Hz electric field with low amplitudes changes the membrane potential in pancreatic β-cells.

  10. Flow cytometric quantification of all phases of the cell cycle and apoptosis in a two-color fluorescence plot.

    Directory of Open Access Journals (Sweden)

    Christine Vignon

    Full Text Available An optimal technology for cell cycle analysis would allow the concomitant measurement of apoptosis, G0, G1, S, G2 and M phases in combination with cell surface phenotyping. We have developed an easy method in flow cytometry allowing this discrimination in an only two-color fluorescent plot. It is based on the concomitant use of 7-amino-actinomycin D and the antibodies anti-Ki67 and anti-phospho(Ser10-histone H3, both conjugated to Alexa Fluor®488 to discriminate G0 and M phases, respectively. The method is particularly valuable in a clinical setting as verified in our laboratory by analyzing human leukemic cells from marrow samples or after exposure to cell cycle modifiers.

  11. Spatiotemporal variations of vegetation cover on the Chinese Loess Plateau(1981―2006):Impacts of climate changes and human activities

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Spatiotemporal variations of Chinese Loess Plateau vegetation cover during 1981-2006 have been investigated using GIMMS and SPOT VGT NDVI data and the cause of vegetation cover changes has been analyzed, considering the climate changes and human activities. Vegetation cover changes on the Loess Plateau have experienced four stages as follows: (1) vegetation cover showed a continued increasing phase during 1981―1989; (2) vegetation cover changes came into a relative steady phase with small fluctuations during 1990―1998; (3) vegetation cover declined rapidly during 1999―2001; and (4) vegetation cover increased rapidly during 2002―2006. The vegetation cover changes of the Loess Plateau show a notable spatial difference. The vegetation cover has obviously increased in the Inner Mongolia and Ningxia plain along the Yellow River and the ecological rehabilitated region of Ordos Plateau, however the vegetation cover evidently decreased in the hilly and gully areas of Loess Plateau, Liupan Mountains region and the northern hillside of Qinling Mountains. The response of NDVI to climate changes varied with different vegetation types. NDVI of sandy land vegetation, grassland and cultivated land show a significant increasing trend, but forest shows a decreasing trend. The results obtained in this study show that the spatiotemporal variations of vegetation cover are the outcome of climate changes and human activities. Temperature is a control factor of the seasonal change of vegetation growth. The increased temperature makes soil drier and unfavors vegetation growth in summer, but it favors vegetation growth in spring and autumn because of a longer growing period. There is a significant correlation between vegetation cover and precipitation and thus, the change in precipitation is an important factor for vegetation variation. The improved agricultural production has resulted in an increase of NDVI in the farmland, and the implementation of large-scale vegetation

  12. Spatiotemporal variations of vegetation cover on the Chinese Loess Plateau (1981―2006): Impacts of climate changes and human activities

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Spatiotemporal variations of Chinese Loess Plateau vegetation cover during 1981-2006 have been investigated using GIMMS and SPOT VGT NDVI data and the cause of vegetation cover changes has been analyzed, considering the climate changes and human activities. Vegetation cover changes on the Loess Plateau have experienced four stages as follows: (1) vegetation cover showed a continued increasing phase during 1981-1989; (2) vegetation cover changes came into a relative steady phase with small fluctuations during 1990-1998; (3) vegetation cover declined rapidly during 1999-2001; and (4) vegetation cover increased rapidly during 2002-2006. The vegetation cover changes of the Loess Plateau show a notable spatial difference. The vegetation cover has obviously increased in the Inner Mongolia and Ningxia plain along the Yellow River and the ecological rehabilitated region of Ordos Plateau, however the vegetation cover evidently decreased in the hilly and gully areas of Loess Plateau, Liupan Mountains region and the northern hillside of Qinling Mountains. The response of NDVI to climate changes varied with different vegetation types. NDVI of sandy land vegetation, grassland and cultivated land show a significant increasing trend, but forest shows a decreasing trend. The results obtained in this study show that the spatiotemporal variations of vegetation cover are the outcome of climate changes and human activities. Temperature is a control factor of the seasonal change of vegetation growth. The increased temperature makes soil drier and unfavors vegetation growth in summer, but it favors vegetation growth in spring and autumn because of a longer growing period. There is a significant correlation between vegetation cover and precipitation and thus, the change in precipitation is an important factor for vegetation variation. The improved agricultural production has resulted in an increase of NDVI in the farmland, and the implementation of large-scale vegetation construction has

  13. Mangiferin induces cell cycle arrest at G2/M phase through ATR-Chk1 pathway in HL-60 leukemia cells.

    Science.gov (United States)

    Peng, Z G; Yao, Y B; Yang, J; Tang, Y L; Huang, X

    2015-05-12

    This study aimed to determine the effect of mangiferin on the cell cycle in HL-60 leukemia cells and expression of the cell cycle-regulatory genes Wee1, Chk1 and CDC25C and to further investigate the molecular mechanisms of the antileukemic action of mangiferin. The inhibitory effect of mangiferin on HL-60 leukemia cell proliferation was determined by the MTT assay. The impact of mangiferin on the HL-60 cell cycle was evaluated by flow cytometry. After the cells were treated with different concentrations of mangiferin, the expression levels of Wee1, Chk1 and CDC25C mRNA were determined by RT-PCR, and Western blot was used to evaluate the expression levels of cdc25c, cyclin B1, and Akt proteins. The inhibition of HL-60 cell growth by mangiferin was dose- and time-dependent. After treatment for 24 h, cells in G2/M phase increased, and G2/M phase arrest appeared with increased mRNA expression of Wee1, Chk1 and CDC25C. Mangiferin inhibited Chk1 and cdc25c mRNA expression at high concentrations and induced Wee1 mRNA expression in a dose-dependent manner. It significantly inhibited ATR, Chk1, Wee1, Akt, and ERK1/2 phosphorylation but increased cdc2 and cyclin B1 phosphorylation. Furthermore, mangiferin reduced cdc25c, cyclin B1, and Akt protein levels while inducing Wee1 protein expression. It also antagonized the phosphorylation effect of vanadate on ATR, and the phosphorylation effect of EGF on Wee1. These findings indicated that mangiferin inhibits cell cycle progression through the ATR-Chk1 stress response DNA damage pathway, leading to cell cycle arrest at G2/M phase in leukemia cells.

  14. Normal and malignant epithelial cells with stem-like properties have an extended G2 cell cycle phase that is associated with apoptotic resistance

    Directory of Open Access Journals (Sweden)

    Biddle Adrian

    2010-04-01

    Full Text Available Abstract Background Subsets of cells with stem-like properties have been previously isolated from human epithelial cancers and their resistance to apoptosis-inducing stimuli has been related to carcinoma recurrence and treatment failure. The aim of this study was to investigate the mechanisms of resistance to apoptosis-inducing agents of cells with stem-like properties in both normal and malignant human epithelia. Methods Cells isolated from fresh human head and neck carcinomas (n = 11, cell lines derived from head and neck, prostate and breast human carcinomas (n = 7, and from normal human oral mucosa (n = 5, were exposed to various apoptosis-inducing stimuli (UV, Tumour Necrosis Factor, Cisplatin, Etoposide, and Neocarzinostatin. Flow cytometry for CD44 and epithelial-specific antigen (ESA expression, colony morphology, tumour sphere formation and rapid adherence assays were used to identify the subset of cells with stem-like properties. Apoptosis, cell cycle and expression of various cell cycle checkpoint proteins were assessed (Western Blot, qPCR. The role of G2-checkpoint regulators Chk1 and Chk2 was investigated by use of debromohymenialdisine (DBH and siRNA. Results In both cancer biopsies and carcinoma cell lines a subset of CD44high cells showed increased clonogenicity, a significantly lower rate of apoptosis, and a significantly higher proportion of cells in the G2-phase of the cell cycle. An inverse correlation between the percentage of cells in G2-phase and the rate of apoptosis was found. Pulse-chase with iododeoxyuridine (IdU demonstrated that CD44high carcinoma cells spent longer time in G2, even in un-treated controls. These cells expressed higher levels of G2 checkpoint proteins, and their release from G2 with BDH or Chk1 siRNA increased their rate of apoptosis. Low passage cultures of normal keratinocytes were also found to contain a subset of CD44high cells showing increased clonogenicity, and a similar pattern of G2-block

  15. Phase I clinical trial of fibronectin CH296-stimulated T cell therapy in patients with advanced cancer.

    Directory of Open Access Journals (Sweden)

    Takeshi Ishikawa

    Full Text Available BACKGROUND: Previous studies have demonstrated that less-differentiated T cells are ideal for adoptive T cell transfer therapy (ACT and that fibronectin CH296 (FN-CH296 together with anti-CD3 resulted in cultured cells that contain higher amounts of less-differentiated T cells. In this phase I clinical trial, we build on these prior results by assessing the safety and efficacy of FN-CH296 stimulated T cell therapy in patients with advanced cancer. METHODS: Patients underwent fibronectin CH296-stimulated T cell therapy up to six times every two weeks and the safety and antitumor activity of the ACT were assessed. In order to determine immune function, whole blood cytokine levels and the number of peripheral regulatory T cells were analyzed prior to ACT and during the follow up. RESULTS: Transferred cells contained numerous less-differentiated T cells greatly represented by CD27+CD45RA+ or CD28+CD45RA+ cell, which accounted for approximately 65% and 70% of the total, respectively. No ACT related severe or unexpected toxicities were observed. The response rate among patients was 22.2% and the disease control rate was 66.7%. CONCLUSIONS: The results obtained in this phase I trial, indicate that FN-CH296 stimulated T cell therapy was very well tolerated with a level of efficacy that is quite promising. We also surmise that expanding T cell using CH296 is a method that can be applied to other T- cell-based therapies. TRIAL REGISTRATION: UMIN UMIN000001835.

  16. HIV Replication Is Not Controlled by CD8+ T Cells during the Acute Phase of the Infection in Humanized Mice.

    Directory of Open Access Journals (Sweden)

    Nicolas Y Petit

    Full Text Available HIV replication follows a well-defined pattern during the acute phase of the infection in humans. After reaching a peak during the first few weeks after infection, viral replication resolves to a set-point thereafter. There are still uncertainties regarding the contribution of CD8(+ T cells in establishing this set-point. An alternative explanation, supported by in silico modeling, would imply that viral replication is limited by the number of available targets for infection, i.e. CD4(+CCR5(+ T cells. Here, we used NOD.SCID.gc(-/- mice bearing human CD4(+CCR5(+ and CD8(+ T cells derived from CD34(+ progenitors to investigate the relative contribution of both in viral control after the peak. Using low dose of a CCR5-tropic HIV virus, we observed an increase in viral replication followed by "spontaneous" resolution of the peak, similar to humans. To rule out any possible role for CD8(+ T cells in viral control, we infected mice in which CD8(+ T cells had been removed by a depleting antibody. Globally, viral replication was not affected by the absence of CD8(+ T cells. Strikingly, resolution of the viral peak was equally observed in mice with or without CD8(+ T cells, showing that CD8(+ T cells were not involved in viral control in the early phase of the infection. In contrast, a marked and specific loss of CCR5-expressing CD4(+ T cells was observed in the spleen and in the bone marrow, but not in the blood, of infected animals. Our results strongly suggest that viral replication during the acute phase of the infection in humanized mice is mainly constrained by the number of available targets in lymphoid tissues rather than by CD8(+ T cells.

  17. HIV Replication Is Not Controlled by CD8+ T Cells during the Acute Phase of the Infection in Humanized Mice.

    Science.gov (United States)

    Petit, Nicolas Y; Lambert-Niclot, Sidonie; Marcelin, Anne-Geneviève; Garcia, Sylvie; Marodon, Gilles

    2015-01-01

    HIV replication follows a well-defined pattern during the acute phase of the infection in humans. After reaching a peak during the first few weeks after infection, viral replication resolves to a set-point thereafter. There are still uncertainties regarding the contribution of CD8(+) T cells in establishing this set-point. An alternative explanation, supported by in silico modeling, would imply that viral replication is limited by the number of available targets for infection, i.e. CD4(+)CCR5(+) T cells. Here, we used NOD.SCID.gc(-/-) mice bearing human CD4(+)CCR5(+) and CD8(+) T cells derived from CD34(+) progenitors to investigate the relative contribution of both in viral control after the peak. Using low dose of a CCR5-tropic HIV virus, we observed an increase in viral replication followed by "spontaneous" resolution of the peak, similar to humans. To rule out any possible role for CD8(+) T cells in viral control, we infected mice in which CD8(+) T cells had been removed by a depleting antibody. Globally, viral replication was not affected by the absence of CD8(+) T cells. Strikingly, resolution of the viral peak was equally observed in mice with or without CD8(+) T cells, showing that CD8(+) T cells were not involved in viral control in the early phase of the infection. In contrast, a marked and specific loss of CCR5-expressing CD4(+) T cells was observed in the spleen and in the bone marrow, but not in the blood, of infected animals. Our results strongly suggest that viral replication during the acute phase of the infection in humanized mice is mainly constrained by the number of available targets in lymphoid tissues rather than by CD8(+) T cells.

  18. Conductance fluctuations and disorder induced ν =0 quantum Hall plateau in topological insulator nanowires

    Science.gov (United States)

    Xypakis, Emmanouil; Bardarson, Jens H.

    2017-01-01

    Clean topological insulators exposed to a magnetic field develop Landau levels accompanied by a nonzero Hall conductivity for the infinite slab geometry. In this work we consider the case of disordered topological insulator nanowires and find, in contrast, that a zero Hall plateau emerges within a broad energy window close to the Dirac point. We numerically calculate the conductance and its distribution for a statistical ensemble of disordered nanowires, and use the conductance fluctuations to study the dependence of the insulating phase on system parameters, such as the nanowire length, disorder strength, and the magnetic field.

  19. Phase II trial of second-line erlotinib and digoxin for nonsmall cell lung cancer (NSCLC

    Directory of Open Access Journals (Sweden)

    Fadi Kayali

    2011-02-01

    Full Text Available Fadi Kayali, Muhamad A Janjua, Damian A Laber, Donald Miller, Goetz H KloeckerUniversity of Louisville, James Graham Brown Cancer Center, Louisville, KY, USABackground: In vitro digoxin sensitizes cancer cells to the induction of apoptosis by chemotherapy. Inhibition of the Na/K-ATPase enzyme by ouabain disturbs the intracellular ion composition of cancer cells, altering cellular homeostasis. This suggests that inhibition of the Na/K pump results in cellular sensitization of malignant but not benign cells to the induction of apoptosis. Epidemiologic studies have also shown beneficial effects of digitalis in breast cancer incidence. At ASCO (American Society of Clinical Oncology 2007 our group presented a Phase II study showing encouraging results by adding digoxin to biochemotherapy for melanoma. Erlotinib is one of the standard second-line treatments for nonsmall cell lung cancer (NSCLC, with a response rate (RR of 10%. This study's hypothesis was that adding digoxin to erlotinib will improve the RR and time to progression (TTP in NSCLC.Methods: Patients with progressive disease (PD after chemotherapy were enrolled if they had an ECOG (Eastern Cooperative Oncology Group score from 0 to 2 and good organ function. Daily erlotinib 150 mg and digoxin 0.25 mg were taken by mouth. The digoxin dose was adjusted to keep levels between 1 and 2 ng/mL. Computed tomography scans were done every 6 weeks. Treatment continued until PD or significant toxicity occurred.Results: Patient accrual lasted from March 2006 until August 2008 and was stopped early at the time of interim analysis. Twenty-eight patients were enrolled, and 24 who completed at least 6 weeks of therapy are presented here. All patients had unresectable NSCLC stage III/IV at diagnosis. Median age was 61 (34–78, 14 were female, 17 had prior radiation (not involving the target lesions, 23 had one prior chemotherapy, and one subject had two. Only one patient was a never-smoker. Histologies were

  20. Silencing Snail suppresses tumor cell proliferation and invasion by reversing epithelial-to-mesenchymal transition and arresting G2/M phase in non-small cell lung cancer.

    Science.gov (United States)

    Yang, Xueying; Han, Mengmeng; Han, Haibo; Wang, Bingjing; Li, Sheng; Zhang, Zhiqian; Zhao, Wei

    2017-04-01

    Epithelial-to-mesenchymal transition (EMT) is essential for tumor invasion and metastasis. Snail has been proven to be a key regulator of EMT. Several studies have shown compelling evidence that Snail is also an important regulator of tumor growth and aggression; however, the role of Snail in the cell cycle has not been clarified. We decreased Snail expression by siRNA transfection and lentiviral‑mediated RNAi, to explore the effect of silencing Snail on the tumorigenicity and migration of lung carcinoma (lung cancer) cells. The results showed that silencing Snail conferred significant anti-proliferative activity and inhibited cell migration, tumor growth and metastasis both in vitro and in vivo. To understand the mechanism of these effects, we further investigated correlations among Snail expression, EMT and cell cycle. Significantly, Snail knockdown reversed EMT processes in lung cancer cells. Furthermore, the cyclin-dependent kinase inhibitor P21 was upregulated after silencing Snail. P21 upregulation manifested its tumor suppressor effects and arrested cells in the G2/M phase, not the G1/S phase following Snail depletion in lung cancer cells. These data suggest that silencing Snail decreases the malignant behaviors of lung cancer cells by reversing EMT processes and causing cell cycle defects.

  1. Dosimetric investigations of laser-induced phase transition of MX1-cell membranes by use of quantum dots

    Science.gov (United States)

    Beuthan, J.; Dressler, C.; Minet, O.; Müller, G.

    2006-05-01

    It is well known that laser scattered-light applicators when applied for laser-induced tumor therapy allow the precise thermal destruction of metastases. Using laser radiation in the NIR spectral range (usually, Nd:YAG laser systems λ = 1064 nm), a penetration depth of 5-10 cm (1/ e is the decrease in radiation intensity) is achieved in biological tissues. The major tissue-optical parameters, i.e., absorption coefficient μa, scattering coefficient μs, and the anisotropy factor g, show biological tissues to be strongly scattering media which have a so-called optical window in the NIR. As a consequence, the therapeutic laser radiation is scattered and absorbed at a deeper level, leading to a virtual enlargement of the laser applicator. The thermal sclerotization and the thermal cell damage originate within the absorbing volume of the laser radiation and spread outward by thermal diffusion. There are three dosimetrically relevant zones of thermal and biological damage: (1) a zone of thermal coagulation; (2) a threshold of partial necrosis (destruction of all metabolic processes in the cell is the maintenance of essential parts of the cytoskeleton and the plasma membrane); this is characterized by a specific temperature range, the so-called phase transition, which refers to the transition from the gel phase of the biomembrane to the fluid phase; the determination of this temperature zone is an integral part of the following experimental investigations on MX1 cells; (3) an external zone of thermal effects made up of partial and multiple damage with a statistical chance of survival. This paper describes the investigations on heat stress in cancer cells to verify the maximum phase transition of the outer MX1 cell membranes and the related results. For this purpose, a novel method of quantum dot fluorescence dosimetry was developed. The evaluation of the measured laser-induced fluorescences yields a first approximation of the determination of the phase transition on MX1

  2. Total knee arthroplasty and fractures of the tibial plateau

    Science.gov (United States)

    Softness, Kenneth A; Murray, Ryan S; Evans, Brian G

    2017-01-01

    Tibial plateau fractures are common injuries that occur in a bimodal age distribution. While there are various treatment options for displaced tibial plateau fractures, the standard of care is open reduction and internal fixation (ORIF). In physiologically young patients with higher demand and better bone quality, ORIF is the preferred method of treating these fractures. However, future total knee arthroplasty (TKA) is a consideration in these patients as post-traumatic osteoarthritis is a common long-term complication of tibial plateau fractures. In older, lower demand patients, ORIF is potentially less favorable for a variety of reasons, namely fixation failure and the need for delayed weight bearing. In some of these patients, TKA can be considered as primary mode of treatment. This paper will review the literature surrounding TKA as both primary treatment and as a salvage measure in patients with fractures of the tibial plateau. The outcomes, complications, techniques and surgical challenges are also discussed.

  3. Phylogeography of regional fauna on the Tibetan Plateau: A review

    Institute of Scientific and Technical Information of China (English)

    Shujuan Yang; Hailiang Dong; Fumin Lei

    2009-01-01

    The studies of uplift and glaciations of the Tibetan Plateau are summarized, and a series of recent case studies of the endemic species based on DNA sequences are detailed. In general, these molecular data show that all the organisms originated from Early Pliocene to Late Miocene, and then multi-stages of divergence/speciation occurred within each taxa following their original occupation on the pla-teau, mainly as a result of periodic glacial cycles and geographic isolation. The regional fauna may have undergone several range con-tractions and expansions during the Pleistocene glaciations. However, the population expansion and refugia may vary in space, time, and extent. The regional fauna of the Tibetan Plateau may be combinations of ancient movement from adjacent zoogeographical regions, speciation in situ, and postglacial colonization from adjacent areas. Geomorphic and climatic changes on the plateau definitely have a remarkable influence on the regional and adjacent biogeographic patterns, and the mechanism is very complex.

  4. The Colorado Plateau coal assessment study area, 2000 (cpstdyg)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This is a coverage of the Colorado Plateau coal assessment study area. The study area outline was drawn on the county lines that most closely outline the...

  5. A plateau-valley separation method for multifunctional surfaces characterization

    DEFF Research Database (Denmark)

    Godi, Alessandro; Kühle, A.; De Chiffre, Leonardo

    2012-01-01

    Turned multifunctional surfaces are a new typology of textured surfaces presenting a flat plateau region and deterministically distributed lubricant reservoirs. Existing standards are not suitable for the characterization of such surfaces, providing at times values without physical meaning. A new...

  6. Flora investigation kicks off on Qinghai-Tibet Plateau

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Coordinated by the CAS Kunming Institute of Botany,a project to investigate the floral germplasm resources on the Qinghai-Tibet Plateau was initiated recently in Kunming,capital of southwest China's Yunnan Province.

  7. Lipopolysaccharide binding protein and serum amyloid A secretion by human intestinal epithelial cells during the acute phase response.

    Science.gov (United States)

    Vreugdenhil, A C; Dentener, M A; Snoek, A M; Greve, J W; Buurman, W A

    1999-09-01

    The acute phase proteins LPS binding protein (LBP) and serum amyloid A (SAA) are produced by the liver and are present in the circulation. Both proteins have been shown to participate in the immune response to endotoxins. The intestinal mucosa forms a large surface that is continuously exposed to these microbial products. By secretion of antimicrobial and immunomodulating agents, the intestinal epithelium contributes to the defense against bacteria and their products. The aim of this study was to explore the influence of the inflammatory mediators TNF-alpha, IL-6, and IL-1beta on the release of LBP and SAA by intestinal epithelial cells (IEC). In addition, the induction of LBP and SAA release by cell lines of intestinal epithelial cells and hepatic cells was compared. The data obtained show that in addition to liver cells, IEC also expressed LBP mRNA and released bioactive LBP and SAA upon stimulation. Regulation of LBP and SAA release by IEC and hepatocytes was typical for class 1 acute phase proteins, although differences in regulation between the cell types were observed. Endotoxin did not induce LBP and SAA release. Glucocorticoids were demonstrated to strongly enhance the cytokine-induced release of LBP and SAA by IEC, corresponding to hepatocytes. The data from this study, which imply that human IEC can produce LBP and SAA, suggest a role for these proteins in the local defense mechanism of the gut to endotoxin. Furthermore, the results demonstrate that tissues other than the liver are involved in the acute phase response.

  8. Sichuan Basin and beyond: Eastward foreland growth of the Tibetan Plateau from an integration of Late Cretaceous-Cenozoic fission track and (U-Th)/He ages of the eastern Tibetan Plateau, Qinling, and Daba Shan

    Science.gov (United States)

    Yang, Zhao; Shen, Chuanbo; Ratschbacher, Lothar; Enkelmann, Eva; Jonckheere, Raymond; Wauschkuhn, Bastian; Dong, Yunpeng

    2017-06-01

    Combining 121 new fission track and (U-Th)/He ages with published thermochronologic data, we investigate the Late Cretaceous-Cenozoic exhumation/cooling history of the eastern Tibetan Plateau, Qinling, Daba Shan, and Sichuan Basin of east central China. The Qinling orogen shows terminal southwestward foreland growth in the northern Daba Shan thrust belt at 100-90 Ma and in the southern Daba Shan fold belt at 85-70 Ma. The eastern margin of Tibetan Plateau experienced major exhumation phases at 70-40 Ma (exhumation rate 0.05-0.08 mm/yr), 25-15 Ma (≤1 mm/yr in the Pengguan Massif; 0.2 mm/yr in the imbricated western Sichuan Basin), and since 11-10 Ma along the Longmen Shan ( 0.80 mm/yr) and the interior of the eastern Tibetan Plateau (Dadu River gorge, Min Shan; 0.50 mm/yr). The Sichuan Basin records two basin-wide denudation phases, likely a result of the reorganization of the upper Yangtze River drainage system. The first phase commenced at 45 Ma and probably ended before the Miocene; >1 km of rocks were eroded from the central and eastern Sichuan Basin. The second phase commenced at 12 Ma and denudated the central Sichuan Basin, Longmen Shan, and southern Daba Shan; more than 2 km of rocks were eroded after the lower Yangtze River had cut through the Three Gorges and captured the Sichuan Basin drainage. In contrast to the East Qinling, which was weakly effected by late Cenozoic exhumation, the West Qinling and Daba Shan have experienced rapid exhumation/cooling since 15-13 Ma, a result of growth of the Tibetan Plateau beyond the Sichuan Basin.

  9. Work plan for phase 1A paleochannel studies at the Cheney disposal cell, Grand Junction, Colorado: Draft

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-11-01

    This document will serve as a Work Plan for continuing paleochannel characterization activities at the Cheney disposal site near Grand Junction, Colorado. Elevated levels of nitrate were encountered in ground water from two monitor wells installed in alluvial paleochannels near the Cheney disposal cell in 1994. This triggered a series of investigations (Phase 1) designed to determine the source of nitrate and other chemical constituents in ground water at the site. A comprehensive summary of the Phase 1 field investigations (limited to passive monitoring and modeling studies) conducted by the Remedial Action Contractor (RAC) and Technical Assistance Contractor (TAC) to date is provided in Section 2.0 of this document. Results of Phase 1 were inconclusive regarding the potential interaction between the disposal cell and the paleochannels, so additional Phase 1A investigations are planned. Recommendations for Phase 1A tasks and possible future activities are discussed in Section 3.0. Detailed information on the implementation of the proposed Phase 1A tasks appears in Section 4.0 and will provide the basis for Statements of Work (SOW) for each of these tasks. A detailed sampling plan is provided to ensure quality and a consistency with previous data collection efforts.

  10. The Colorado Plateau II : Biophysical, Socioeconomic, and Cultural Research

    OpenAIRE

    Van Riper, Charles; Mattson, David J.

    2005-01-01

    Abstract from GoogleBooks: The publication of The Colorado Plateau: Cultural, Biological, and Physical Research in 2004 marked a timely summation of current research in the Four Corners states. This new volume, derived from the seventh Biennial Conference on the Colorado Plateau in 2003, complements the previous book by again focusing on the integration of science into resource management issues. The 32 chapters range in content from measuring human impacts on cultural resources, through graz...

  11. The Colorado Plateau II : Biophysical, Socioeconomic, and Cultural Research

    OpenAIRE

    Van Riper, Charles; Mattson, David J.

    2005-01-01

    Abstract from GoogleBooks: The publication of The Colorado Plateau: Cultural, Biological, and Physical Research in 2004 marked a timely summation of current research in the Four Corners states. This new volume, derived from the seventh Biennial Conference on the Colorado Plateau in 2003, complements the previous book by again focusing on the integration of science into resource management issues. The 32 chapters range in content from measuring human impacts on cultural resources, through graz...

  12. AHP 21: Pyramid Schemes on the Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Devin Gonier

    2017-09-01

    Full Text Available The unique features of pyramid shemes and certain underlying causes for their development on the Tibetan Plateau are analyzed. Research was conducted by analyzing 521 surveys, allowing estimation of pyramid scheme activity on the Plateau and an identification of related cultural and social specificities. Firsthand accounts were collected revealing details of personal involvement. Survey data and similarities in the accounts were studied to suggest how involvement in pyramid schemes might be reduced at both institutional and individual levels.

  13. Evolution of the Ordos Plateau and environmental effects

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the analysis of temporary-spatial distribution, geomorphic position, contact relationship with underlying strata and grain size of red clay, we studied the formation and environmental background of red clay. During late Miocene-Pliocene, the Ordos Block finished the transformation from the basin to the plateau, which had an obvious environmental effect on the topography, indicated by the formation of highland undergoing wind erosion and lowland receiving red clay deposits. The red clay materials were sourced from dusts carried by wind energy and covered on the initial topography. Unlike Quaternary loess dust covering the overall the Loess Plateau, red clay deposited on the highland would be transported to the lowlands by wind and fluvial process. As a result, there was no continuous "Red Clay Plateau" in the Ordos region and red clay was only preserved in former lowlands. However, red clay was discontinuously distributed through the Loess Plateau and to some extent modified the initial topography. The differential uplift in interior plateau is indicated by the uplift of northern Baiyushan, central Ziwuling and southern Weibeibeishan. The Weibeibeishan Depression formed earlier and became the sedimentary center of red clay resulting in the thicker red clay deposits in Chaona, Lingtai and Xunyi. Since Quaternary the aridity in the northern plateau enhanced and accelerated loess accumulation caused the formation of the Loess Plateau. During the late Pleistocene the rapid uplift led to the enhancement of erosion. Especially after the cut-through of Sanme Lake by the Yellow River, the decline of base level caused the falling of ground water level and at the same time the increase of drainage density resulting in the enhancement of evaporation capacity, which enhanced the aridity tendency of aridity in the Loess Plateau region.

  14. In vitro motility of cells from human epidermoid carcinomas. A study by phase-contrast and reflection-contrast cinematography.

    Science.gov (United States)

    Haemmerli, G; Sträuli, P

    1981-05-15

    The motile behavior of six cell lines derived from human squamous carcinomas (two from the larynx, four from the tongue) was studied by cinematography under phase- and reflection-contrast illumination. The recorded cell activities consist in spreading, stationary and translocation motility, and aggregate formation. Within this common pattern, quantitative modifications ("sub-pattern") are stable properties of the individual cells lines. Such modifications are particularly evident with regard to the dynamic texture of the aggregates which ranges from loose, netlike structures to compact islands with smooth borders. Accordingly, the intensity of cell traffic within and around the aggregates varies considerably. It is discussed to what extent the in vitro motility of the carcinoma cell populations reflects their behavior in the organism and thus the significance of cell movements for invasion.

  15. Real-time and non-invasive measurements of cell mechanical behaviour with optical coherence phase microscopy

    Science.gov (United States)

    Gillies, D.; Gamal, W.; Downes, A.; Reinwald, Y.; Yang, Y.; El Haj, A.; Bagnaninchi, P. O.

    2017-02-01

    There is an unmet need in tissue engineering for non-invasive, label-free monitoring of cell mechanical behaviour in their physiological environment. Here, we describe a novel optical coherence phase microscopy (OCPM) set-up which can map relative cell mechanical behaviour in monolayers and 3D systems non-invasively, and in real-time. 3T3 and MCF-7 cells were investigated, with MCF-7 demonstrating an increased response to hydrostatic stimulus indicating MCF-7 being softer than 3T3. Thus, OCPM shows the ability to provide qualitative data on cell mechanical behaviour. Quantitative measurements of 6% agarose beads have been taken with commercial Cell Scale Microsquisher system demonstrating that their mechanical properties are in the same order of magnitude of cells, indicating that this is an appropriate test sample for the novel method described.

  16. Gatifloxacin induces S and G2-phase cell cycle arrest in pancreatic cancer cells via p21/p27/p53.

    Directory of Open Access Journals (Sweden)

    Vikas Yadav

    Full Text Available Pancreatic cancer, despite being the most dreadful among gastrointestinal cancers, is poorly diagnosed, and further, the situation has been aggravated owing to acquired drug resistance against the single known drug therapy. While previous studies have highlighted the growth inhibitory effects of older generation fluoroquinolones, the current study aims to evaluate the growth inhibitory effects of newer generation fluoroquinolone, Gatifloxacin, on pancreatic cancer cell lines MIA PaCa-2 and Panc-1 as well as to elucidate the underlying molecular mechanisms. Herein, we report that Gatifloxacin suppresses the proliferation of MIA PaCa-2 and Panc-1 cells by causing S and G(2-phase cell cycle arrest without induction of apoptosis. Blockade in S-phase of the cell cycle was associated with increased TGF-β1 expression and translocation of Smad3-4 complex to the nucleus with subsequent activation of p21 in MIA PaCa-2 cells, whereas TGF-β signalling attenuated Panc-1 cells showed S-phase arrest by direct activation of p27. However, Gatifloxacin mediated G(2-phase cell cycle arrest was found to be p53 dependent in both the cell lines. Our study is of interest because fluoroquinolones have the ability to penetrate pancreatic tissue which can be very effective in combating pancreatic cancers that are usually associated with loss or downregulation of CDK inhibitors p21/p27 as well as mutational inactivation of p53. Additionally, Gatifloxacin was also found to synergize the effect of Gemcitabine, the only known drug against pancreatic cancer, as well as the broad spectrum anticancer drug cisplatin. Taken together our results suggest that Gatifloxacin possesses anticancer activities against pancreatic cancer and is a promising candidate to be repositioned from broad spectrum antibiotics to anticancer agent.

  17. Computational cell quantification in the human brain tissues based on hard x-ray phase-contrast tomograms

    Science.gov (United States)

    Hieber, Simone E.; Bikis, Christos; Khimchenko, Anna; Schulz, Georg; Deyhle, Hans; Thalmann, Peter; Chicherova, Natalia; Rack, Alexander; Zdora, Marie-Christine; Zanette, Irene; Schweighauser, Gabriel; Hench, Jürgen; Müller, Bert

    2016-10-01

    Cell visualization and counting plays a crucial role in biological and medical research including the study of neurodegenerative diseases. The neuronal cell loss is typically determined to measure the extent of the disease. Its characterization is challenging because the cell density and size already differs by more than three orders of magnitude in a healthy cerebellum. Cell visualization is commonly performed by histology and fluorescence microscopy. These techniques are limited to resolve complex microstructures in the third dimension. Phase- contrast tomography has been proven to provide sufficient contrast in the three-dimensional imaging of soft tissue down to the cell level and, therefore, offers the basis for the three-dimensional segmentation. Within this context, a human cerebellum sample was embedded in paraffin and measured in local phase-contrast mode at the beamline ID19 (ESRF, Grenoble, France) and the Diamond Manchester Imaging Branchline I13-2 (Diamond Light Source, Didcot, UK). After the application of Frangi-based filtering the data showed sufficient contrast to automatically identify the Purkinje cells and to quantify their density to 177 cells per mm3 within the volume of interest. Moreover, brain layers were segmented in a region of interest based on edge detection. Subsequently performed histological analysis validated the presence of the cells, which required a mapping from the two- dimensional histological slices to the three-dimensional tomogram. The methodology can also be applied to further tissue types and shows potential for the computational tissue analysis in health and disease.

  18. In vitro effects of imatinib on CD34+ cells of patients with chronic myeloid leukemia in the megakaryocytic crisis phase

    Science.gov (United States)

    MENG, FANKAI; ZENG, WEN; HUANG, LIFANG; QIN, SHUANG; MIAO, NINGNING; SUN, HANYING; LI, CHUNRUI

    2014-01-01

    Imatinib is a tailored drug for the treatment of chronic myeloid leukemia (CML), and has substantial activity and a favorable safety profile when used as a single agent in patients with CML in myeloid blast crisis. The megakaryocytic blast crisis in CML occurs rarely and carries a poor prognosis. The aim of the present study was to investigate the effects of imatinib on cluster of differentiation (CD)34+ cells from patients with CML in the megakaryocytic crisis phase. Bone marrow mononuclear cells (BMNCs) were isolated from patients with CML in the megakaryocytic crisis phase. CD34+ cells were selected from BMNCs by positive immunomagnetic column separation. Imatinib significantly induced G1 arrest, reduced the phosphorylation of cyclin-dependent kinase 1 and retinoblastoma proteins and inhibited the proliferation of CD34+ cells from patients with CML in the megakaryocytic crisis phase. Annexin V/propidium iodide and caspase-3 activity showed that imatinib induced apoptosis. Western blot analysis and protein tyrosine kinase activity assays showed that imatinib inhibited BCR-ABL protein tyrosine kinase activity. The in vitro data thus markedly indicate a potential clinical application of imatinib for patients with CML in the megakaryocytic crisis phase. PMID:24527087

  19. In vitro effects of imatinib on CD34(+) cells of patients with chronic myeloid leukemia in the megakaryocytic crisis phase.

    Science.gov (United States)

    Meng, Fankai; Zeng, Wen; Huang, Lifang; Qin, Shuang; Miao, Ningning; Sun, Hanying; Li, Chunrui

    2014-03-01

    Imatinib is a tailored drug for the treatment of chronic myeloid leukemia (CML), and has substantial activity and a favorable safety profile when used as a single agent in patients with CML in myeloid blast crisis. The megakaryocytic blast crisis in CML occurs rarely and carries a poor prognosis. The aim of the present study was to investigate the effects of imatinib on cluster of differentiation (CD)34(+) cells from patients with CML in the megakaryocytic crisis phase. Bone marrow mononuclear cells (BMNCs) were isolated from patients with CML in the megakaryocytic crisis phase. CD34(+) cells were selected from BMNCs by positive immunomagnetic column separation. Imatinib significantly induced G1 arrest, reduced the phosphorylation of cyclin-dependent kinase 1 and retinoblastoma proteins and inhibited the proliferation of CD34(+) cells from patients with CML in the megakaryocytic crisis phase. Annexin V/propidium iodide and caspase-3 activity showed that imatinib induced apoptosis. Western blot analysis and protein tyrosine kinase activity assays showed that imatinib inhibited BCR-ABL protein tyrosine kinase activity. The in vitro data thus markedly indicate a potential clinical application of imatinib for patients with CML in the megakaryocytic crisis phase.

  20. A van der Waals-like Transition Between Normal and Cancerous Phases in Cell Populations Dynamics of Colorectal Cancer

    Science.gov (United States)

    Qiu, Kang; Wang, Li-Fang; Shen, Jian; Yousif, Alssadig A. M.; He, Peng; Shao, Dan-Dan; Zhang, Xiao-Min; Kirunda, John B.; Jia, Ya

    2016-11-01

    Based on a deterministic continuous model of cell populations dynamics in the colonic crypt and in colorectal cancer, we propose four combinations of feedback mechanisms in the differentiations from stem cells (SCs) to transit cells (TCs) and then to differentiated cells (DCs), the four combinations include the double linear (LL), the linear and saturating (LS), the saturating and linear (SL), and the double saturating (SS) feedbacks, respectively. The relative fluctuations of the population of SCs, TCs, and DCs around equilibrium states with four feedback mechanisms are studied by using the Langevin method. With the increasing of net growth rate of TCs, it is found that the Fano factors of TCs and DCs go to a peak in a transient phase, and then increase again to infinity in the cases of LS and SS feedbacks. The “up-down-up” characteristic on the Fano factor (like the van der Waals loop) demonstrates that there exists a transient phase between the normal and cancerous phases, our novel findings suggest that the mathematical model with LS or SS feedback might be better to elucidate the dynamics of a normal and abnormal (cancerous) phases.

  1. Cabozantinib versus everolimus in advanced renal cell carcinoma (METEOR): final results from a randomised, open-label, phase 3 trial

    DEFF Research Database (Denmark)

    Choueiri, Toni K; Escudier, Bernard; Powles, Thomas

    2016-01-01

    BACKGROUND: Cabozantinib is an oral inhibitor of tyrosine kinases including MET, VEGFR, and AXL. The randomised phase 3 METEOR trial compared the efficacy and safety of cabozantinib versus the mTOR inhibitor everolimus in patients with advanced renal cell carcinoma who progressed after previous V...

  2. The effect of yeast cell wall supplementation on the physiological and acute phase responses of crossbred heifers to endotoxin challenge

    Science.gov (United States)

    A study was conducted to determine the effect of feeding yeast cell wall (YCW) products on the physiological and acute phase responses of crossbred newly-received heifers to endotoxin (lipopolysaccharide; LPS) challenge. Heifers (n=24; 218.9+/-2.4 kg) were obtained from commercial sale barns and tra...

  3. Yeast cell wall supplementation alters the physiological and acute phase responses of crossbred heifers to an endotoxin challenge

    Science.gov (United States)

    A study was conducted to determine the effect of feeding yeast cell wall (YCW) products on the physiological and acute phase responses of crossbred newly-received heifers to an endotoxin challenge. Heifers (n = 24; 219 ± 2.4 kg) were separated into treatment groups receiving a Control diet (n = 8), ...

  4. DEMONSTRATION OF FUEL CELLS TO RECOVER ENERGY FROM ANAEROBIC DIGESTER GAS - PHASE I. CONCEPTUAL DESIGN, PRELIMINARY COST, AND EVALUATION STUDY

    Science.gov (United States)

    The report discusses Phase I (a conceptual design, preliminary cost, and evaluation study) of a program to demonstrate the recovery of energy from waste methane produced by anaerobic digestion of waste water treatment sludge. The fuel cell is being used for this application becau...

  5. Clinical efficacy of zanolimumab (HuMax-CD4): two phase 2 studies in refractory cutaneous T-cell lymphoma

    DEFF Research Database (Denmark)

    Kim, Youn H; Duvic, Madeleine; Obitz, Erik

    2007-01-01

    The efficacy and safety of zanolimumab in patients with refractory cutaneous T-cell lymphoma (CTCL) have been assessed in two phase 2, multicenter, prospective, open-label, uncontrolled clinical studies. Patients with treatment refractory CD4(+) CTCL (mycosis fungoides [MF], n = 38; Sézary syndrome...